BIOLOGY
R
G

THE

CYCLOPEDIA

ANATOMY AND PHYSIOLOGY

VOL. II.
DIA INS

1836-1839

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. II.
DIA INS

1836 — 1839

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

Tb

CONTENTS OF THE SECOND VOLUME

Page |

Diaphragm Dr. Benson 1

Digestion Dr. Bostock 6

Digestive Canal Dr. Grant 27

Echinodermata Dr. Sharpey 30

Edentata T. Bell, Esq 46

Elasticity Dr. Brenan 65

Elbow, Region of the Dr. Hart 62

Elbow, Joint of, )

I Dr. Hart 65

Normal Anatomy '

Elbow, Joint of, Ab- »

{ R. Adams, Esq. .. 67
normal Anatomy .. '

Electricity, Animal .. Dr. Coldstream .. 81

Endosmosis I Dr. Dutrochet . . . . 98

Entozoa R.Owen, Esq Ill

Erectile Tissue Dr. Hart 144

Excretion Dr. Alison 147

Extremity Dr. Todd 154

Eye Dr. Jacob 171

Face R. Partridge, Esq. 207

Fascia Dr. Todd 229

Fat W. T. Brande, Esq. 231

Femoral Artery Dr. Alcock 235

Fibrine W. T. Brande, Esq. 257

Fibro-Cartilage Dr. Todd 260

Fibrous Tissue R.D.Grainger,Esq. 263

Fibular Artery Dr, Todd 267

Fifth Pair of Nerves. . Dr. Alcock 268

Foetus Dr. Montgomery.. 316

Foot, Bones and >

\Dr. Todd 338

Joints of '

Foot, Abnormal Con- )

lA.T.S.Dodd,Esq. 347
ditions of '

Foot, Regions and >

\A.T.S.Dodd,E$q. 350
Muscles of >

Fore-arm, Muscles )

, IS. Solly, Esq 361

and Regions of . . '

Fourth Pair of Nerves Dr. Alcock 370

Ganglion R.D.Grainger,Esq. 371

Gasteropoda T. Rymer Jones, Esq. 377

_

*"**"* *« ..... 5">

J f . f

'

Gelatin .......... W. T. Brande, Esq. 404

Generation, Organs > __

J T. Rymer Jones, Esq. 406

Generation ........ Dr. Allen Thomson. . 424

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

Glosso.Pharyngea! \Dr.RM .......... 49,

Nerve .......... >

Glutaeal Region ---- A. T. S. Dodd, Esq. 500

Groin, Region of the Dr. Todd .......... 503

Hxmatosine ...... Dr. Rees .......... 503

Hand, Bones of the Dr. Todd .......... 505

Hand, Abnormal

Coitions of the
Hand, Muscles of f . f ^^^ £

the ... ...... . '

Hand, Regions of the F. T. MlDaugaU, Esq. 523
Hearing, Organ of. . T. W. Jones, Esq. . . 529
Hearing .......... Dr. Todd .......... 564

Heart ............ Dr. Reid .......... 677

Heart, on the -v

Arrangement of > H.

the Fibres of the *
Heart, Abnormal >

Conditions of the >
Heat, Animal ...... Dr. W. F. Edwards . 648

Hermaphroditism . . Dr. Simpson ........ 684

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

Hibernation ...... Dr. Marshall Hall . . 764

Hip-Joint, Normal > „

} H. Hancock, Esq. . . 776
Anatomy ...... *

Hip-Joint, Abnor-

malConditions of *

Hyperaemia ...... Dr. Todd .......... 825

Hypertrophy ...... Dr. Todd .......... 826

Iliac Arteries ...... Dr. Alcock ........ 827

Innominata Artery . H. Hancock, Esq. . . 850

Iiisecta .......... G. Newport, Esq. . . 853

Insectivora ........ T. Bell, Esq. ......994

Searle, Esq ..... 619

Dr. Todd 630

R. Adams, Esq 780

373887

THE

CYCLOP J3DIA

OP

ANATOMY AND PHYSIOLOGY

DIAPHRAGM (in anatomy), (&
3ta, inter, and (pgaoTu, sepio, claudo ; Lat. dia-
phrugma ; Ital. diuframma ; Fr. diaphragme ;
Ger. Zwerchfell; Eng. midriff), the name given
to that musculo-tendmous septum by which the
cavities of the thorax ancTabdomen are separated
from each other in the Mammalia.

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

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

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

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

* C. G. Cams, Comparative Anatomy.

t Tyson.

$ Cuvier, Anat. Comp. vol. iv.

DIAPHRAGM.

orgaja~i which could exM no influence on the
external form ; nor was it to be expected in a
nnjsbte \vh:ch is not wholly v61imtary. In this
article it is in^endsd teMfoferifeis 1st, the form,
structure, and organization of the diaphragm ;
2nd, its uses ; and, 3rd, its malformations and
diseases,

Fig. 1.

Abdominal surface of the diaphragm.
Fig. 2.

Thoracic surface seen from before.
Fig. 3.

Thoracic surface seen from behind, the vertebrae being
removed.

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

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

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

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

DIAPHRAGM.

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

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

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

* Arcus tendineus exterior, Senac.
t Arcus tendineus interior, Id.

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

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

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

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

B 2

DIAPHRAGM.

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

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

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

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

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

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

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

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

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

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

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

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

DIAPHRAGM.

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

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

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

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

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

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

f In violentissima rrspiratione oranino vidi deor-
sum versus abdomen diaphragma convexum reddi.
Haller, Elfin. Phys. lib. viii. sect. 1.

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

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

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

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

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

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

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

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

'•* St-nac.

6

DIGESTION.

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

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

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

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

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

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

t The word phrenic, used with reference to the
diaphragm, as phrenic nerve, phrenic centre, &c.
has its origin in this opinion, ty>Evej, a <f>p>iv, mens,

tanquam mentis sedes.

\ Diet, dcs Sciences Med. art. Diaphragme.

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

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

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

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

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

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

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

For BIBLIOGRAPHY see that of Anatomy (INTRO-
DUCTION).

(Charles Benson.)

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

* Acad. des Sciences, Mem. 1729.

t Dublin Med. Journal, vol. ix. p. 37.

DIGESTION.

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

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

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

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

t Cullen's Physiol. $201.

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

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

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

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

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

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

DIGESTION.

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

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

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

* Linnaeus, Sys. Nat, t. i. p. 16 et alibi j
Shaw's Zool. v. i. Introd, p. vii et alibi.

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

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

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

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

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

DIGESTION.

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

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

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

t Boyer, ubi supra, supposes that the muscular
fibres are arranged in three layers. See also £1-
liotsou's Physiol. p. 78.

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

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

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

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

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

t Haller, El. Phys. xix. 4. 9,0; Boyer, Anat.
t. iv. p. 333 . . 5 ; Berlin, Mem. Acad. pour 1760,
p. 58 et scq.; this writer appears to have been one
of the first who gave us a correct description of t'ae
muscular coats of the stomach.

10

DIGESTION.

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

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

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

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

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

t Richerand, Physiol. $23. § 111, 2.

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

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

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

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

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

DIGESTION.

11

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

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

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

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

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

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

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

The other kind of stomach which we referred
to above as possessing a peculiar structure,
and acting on a different principle from that of
the human species, is the muscular stomach of
certain classes of birds. Birds are not pro-
vided with teeth, or with any apparatus which
can directly serve for the process of mastica-
tion ; yet many of them feed upon hard sub-
stances, which cannot be acted upon by the
gastric juice, until they have undergone some
process, by which they may be comminuted or
ground down into a pulpy mass. This is
effected by the ingluvies, the craw or crop, and
the ventriculus bulbosus or gizzard. The first
* Blumenbach's Comp. Anat. p. 138. note 20.
t Home, ubi supra, p. 363.

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

12

DIGESTION.

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

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

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

* Grew, ubi supra, p. 34 ; Blumenbach, ubi
supra, $ 99 ; Peyer, Anat. Ventr. Gall., in Man-
get, Bibl. Anat. t. i. p. 172; Hunter on the Ani-
mal (Economy, p. 198-9; Clift, in Phil. Trans, for
1807, pi. 5, fig. 1 ; Home's Lect. v. ii. pi. 49, 62 ;
and the art. AVES.

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

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

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

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

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

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

DIGESTION.

13

The most important of the proximate prin-
ciples employed in diet are fibrin, albumen,
oil, jelly, gluten, mucilage, farina, and sugar,
to which may be added some others of less
frequent occurrence. They are derived, more
or less, from almost all the classes of animals
and vegetables, and from nearly all their indi-
vidual parts, their employment being regulated,
in most cases, rather by the facility with which
they are procured,and reduced into a form proper
to be acted upon by the stomach, than by the
quantity of nutritive matter which they con-
tain. This is one of those subjects in which
\ve have to notice the remarkable effects of
habit and custom, both on the functions and
the sensations. VVe find whole tribes of people
living on a diet, which, to those unaccustomed
to it, would be not only in the highest degree
unpalatable, but likevvi'se altogether indiges-
tible ; while, by the various modes of preparing
food, which have been suggested, either by
luxury or by necessity, the most intractable
substances are reduced into a digestible state.*

The writers on dietetics have attempted to
include all substances that are competent to
afford nutrition under a few general principles,
of which, as they exist in nature, they are
supposed to be composed. Cullen, who may
be considered as the first who attempted to in-
troduce correct philosophical principles into
this department of physiology, reduced them
to two, the oily and the saccharine, and endea-
voured to prove that all the animal fluids may
be referred to these principles.f Magendie,
on the contrary, proceeding less upon their
chemical composition than upon the forms
under which they present themselves, classes
alimentary substances under the nine heads of
farinaceous, mucilaginous, saccharine, acidu-
lous, oily, caseous, gelatinous, albuminous,
and fibrinous.]: Dr. Prout, whose views on
this subject are marked by his characteristic
acuteness, reverts to the mode of Cullen, ad-
mitting only of the oily, the saccharine, and
the albuminous principles, which three, he
conceives, form the " groundwork of all orga-
nized bodies. "§

Of animal compounds which are employed

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

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

t Physiol. § 211, and Mat. Med. v. i. p. 1, ch.
1, p. 218 etseq.

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

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

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

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

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

* Prout, ut supra, p. 12.

f It is upon this principle, rather than to the ab-
sence of azote, that we should be disposed to account
for the results of Magendie's experiments, iu which

14

DIGESTION.

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

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

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

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

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

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

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

§ Works, p. 89 et seq.

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

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

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

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

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

DIGESTION.

15

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

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

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

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

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

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

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

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

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

16

DIGESTION.

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

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

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

In this part of our subject there are two

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

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

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

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

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

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

DIGESTION.

17

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

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

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

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

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

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

VOL. II.

of nutriment, are comparatively difficult of
digestion.*

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

* Beaumont, page 275 . . 8 et alibi.

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

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

§ In Spallanzani, § 244.

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

IT Ann. Phil. v. xiii. p. 13.

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

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

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

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

C

18

DIGESTION.

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

But in whatever way, or upon whatever
principle \ve may explain the action of the
gastric fluid upon the aliment, we are irre-
sistibly led to the conclusion, that it is the
physical agent which produces the effect, not
only from those cases, where in consequence
of a preternatural opening into the stomach
we are able to observe the actual phenomena
of digestion, but still more so, by the expe-
riments on what has been termed artificial di-
gestion, especially those of Spallanzani and
Beaumont, where the gastric juice has been
procured, and applied out of the stomach,
and where the process of chymification has
proceeded, as nearly resembling that in the
stomach itself as might reasonably be ex-
pected, considering the unavoidable imper-
fection of the experiment. This imperfection
respects both the mode of obtaining the gastric
juice itself, and the mode of applying it to
the aliment. We reduce the action of the
stomach into somewhat of an unnatural con-
dition in order to procure the secretion, and
in the application of it we are deprived of the
contractile motion of the organ; yet, not-
withstanding these unavoidable circumstances,
the substances were reduced to a state very
considerably resembling that of chyme. That
this change was not produced by a mere me-
chanical action is proved by the circumstance,
that the change in the substances operated on
bore no proportion to the hardness of their
texture or other physical properties. Thus we
find that the gastric fluid acts upon dense
membrane, and in some cases, even upon
bone, while there are other substances, of a
very delicate texture, w7hich are not affected
by it. This kind of selection of certain sub-
stances in preference to others bears so close
an analogy to the operation of chemical affinity,
that we ought not to refuse our assent to the
idea of their belonging to the same class of

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

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

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

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

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

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

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

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

DIGESTION.

10

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

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

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

* Prout, ut supra, v. xiii. p. 12 et alibi. The
difference between chyme and chyle, as well as the
different organs in which they are elaborated, was
well known to some of the older writers, although
not acknowledged ; see Juncker, Conspect. Physiol.
tab. 11 et 25; Vanhelmont, Ortus Med. p. 167, 8,
and Baglivi, Diss. 3. circa bilem.

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

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

<cO.

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

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

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

The chemical analysis of chyle was first
made by Vauquelin, who employed for this

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

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

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

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

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

c 2

20

DIGESTION.

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

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

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

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

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

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

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

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

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

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

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

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

DIGESTION.

21

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

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

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

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

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

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

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

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

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

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

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

t For an account of the doctrines maintained by
the earlier physiologists, the reader is referred to
the treatise of Kernel, De Concoctionibus, Physiol.
lib. vi. cap. 6 ; Boerhaave, Prselect. not. ad $ 86 ;
Haller, El. Phys. xix. 4 et 5 passim j and Blu-
menbach, lustit. Physiol. § 360.

22

DIGESTION.

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

The hypothesis of trituration may be consi-
dered as having originated with the mechanical
physiologists of the seventeenth century, and
was apparently supported by the curious facts,
which were, at that time, more particularly
brought into view and minutely ascertained, of
the great force exercised by the muscular sto-
machs of certain tribes of birds. The facts,
although perhaps in some instances rather ex-
aggerated, were sufficiently curious, but the
deductions from them were incorrect, first, in
extending the analogy from one class of ani-
mals to other classes, where it was altogether
inapplicable; and secondly, in conceiving of
the trituration which takes place in these mus-
cular stomachs, as constituting the proper pro-
cess of digestion, whereas it is merely a preli-
minary process, equivalent to mastication. The
aliment, after it leaves the gizzard, is in the
same state of comminution into which it is re-
duced by the teeth of those animals that are
provided with these organs, and is then sub-
jected to the action of the proper digestive
stomach, and undergoes the process of chymi-
fication. On this point the experiments of
Stevens and Spallanzani, which were referred
1o above, are quite decisive; they show clearly
how far the agency of mechanical action is in-
strumental in the process of digestion, and they
also show that some other principle is essentially
necessary for its completion.*

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

* For an account of the effects of trituration, as
given by some of the older physiologists, the rea-
der is more particularly referred to the works of
Piteairn, who was one of the most learned men of
his time j Dissert, p, 72..9S j Elem. cap, v. p. 25.. 7 :
see also Haller, El. Phys. xix. 5. 1; Hales,
Statical Essays, v. ii. p, 174,5; Cheselden's Anat.
p. 152..5; Fordyce, ut supra, p. 124.. 138 : and
Richerand, Physiol. $ 18.

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

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

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

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

DIGESTION.

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

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

* Tiedemann and Gtnelin, as the result of their
elaborate experimental researches into the nature
of the digestive process, conclude that it consists
essentially in the solution of the aliment by the
gastric juice. Water alone, they observe, at the tem-
perature of the mammalia, is capable of dissolving
many of the articles employed in diet, and'many
which are not soluble in water are so in the" acids
which are found in the stomach, and to these they
are disposed to refer a considerable part of the
operation; Recherches, t. i. p. 363.. 7. We may,
however, remark, that a solution of the alimentary
matters in water, or even in the acids that exist
in the stomach, cannot be supposed to be identical
with chyme.

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

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

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

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

24

DIGESTION.

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

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

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

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

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

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

t Some of the most eminent chemists confine the
process of fermentation to the proximate principles
derived from vegetables ; but this restriction is not
universally adopted, nor does it appear to be neces-
sary.

J Ut supra.

§ Ut supra.

DIGESTION.

25

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

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

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

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

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

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

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

* Prim. Lin. § 368 ; El. Phys. xix. 2, 12.

26

DIGESTION.

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

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

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

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

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

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

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

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

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

$ Mem. sur le vomissement, "p. 19, 2, and
Physiol. t. ii. p. 138..40.

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

DIGESTIVE CANAL.

27

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

BIBLIOGRAPHY. — Acad. del Cimento, Esper.
Fir. 1691. Adelon, in Diet. Sc. Med. t. ix., xxi.
Bagliri, Opera, Lugd. 1704. Baillie's Morbid Anat.
Works by Wardrop, Lond. 1825. Bauer, in Phil.
Trans, for 1821. Beaumont on the gastric juice,
Platts. 1833. Beccaria, in Bonon. Acad. Com.
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Bell (T.) on the teeth, Lond. 1829. Bertin, in
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1751. Borelli, De motu anim. L. B. 1710.
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Carus's Comp. Anat. by Gore, Lond. 1827. Char-
leton, CEcon. anim. Hag. 1681. Chaussier, in
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t. liii. Claussen, De Duodeno, in Sandifort's The-
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Med. Edin. 1789. Cullens Physiology, Edin.
1772. Daubenton, in Buffon, Hist. nat. t. iv. Davy's
Lecture 5 on agriculture, (2d ed.) Lond. 1814.
De Graaf, Tract. Anat. Med. L. B. 1671. Dumas,
Physiologie, Par. 1800. Duverney, in Mem. Acad.
pour 1700. Ehrenberq, in Ann. Sc. Nat. t. ii.
Emmert, in Ann. China, t. Ixxx. Fernel, Univ.
Med. Traj. 1656. Fleming's Zoology, Edin. 1822.
Flourens, in Ann. Sc. Nat. t. xxvii. Fordyce on

stomach. See also the art. " Vomissement," by
Adelon, Diet, de Med. t. xxi. p. 427 et seq. •, also
Blandin's Notes on Bichat, t. iii. p. 460.

* Haller, Prim. Lin. § 652, and El. Phys. xix.
4, 13; Simmering, Corp. Hum. Fab, t. iv. § 178;
Magendie, ut supra.

digestion, (2d ed. ) Lond. 1791. Fox on the teeth,
Lond. 1803. Gturdner, in Ed. Med. Chir. Tr.
vol. i. Hate's Statical essays, (4th ed.) Lond.
1767. Hall, in Quart. Journ. Hartley on man,
Lond. 1791. Hatchett, in Phil. Trans, for 1799.
Haviland, in Camb. Phil. Trans, vol. i. Hodgkin's
Trans, of Edwards, Lond. 1832. Hodgson's Letters
from North America. Home's Lectures on compa-
rative anatomy, Lond. 1814. Home, in Phil.
Trans, for 1806, 7, 8, 21. Hunter on th3 Animal
(Economy. Hunter, in Phil. Trans, for 1772.
Hunter on the teeth, Lond. 1803. Juncker, Con-
spect. Physiol. Kellie, in Brewster's Encyc.
Legallois, CEuvres de, Par. 1824. Leuret Sf Las-
suigne, Recherches sur la digestion, Par. 1825.
Lieutaud, in Mem. Acad. pour 1752. Linnceus,
Syst. nat. (ed. lOa) Holm. 1758. Londe, in Diet.
Med. et Chir. t. ii. Lorry, Sur les alimens, Par.
1781. Lower, De corde, Amsl. 1669. Macaire fy
F. Marcet, in Ann. China, t. ii. Magendie, in Ann.
Chim. et Phys. t. iii. Magendie, in Diet. Sc. Med.
t. ix. Ditto, Sur le Vomissement, Par. 1813.
Marcet, in Med. Chir. Tr. vol. vi. M' Bride's
Essays (2d ed.) Lond. 1767. Montegre, Exper.
sur la digestion, Par. 1824. 'Monro (Prim.),
in Ed. Med. Essays, vol. iv. Monro (Tert.) on
the gullet, Edin. 1811. O'Beirne on defaecation,
Dub. 1833. Paris on diet, Lond. 1826. Parr's
Med. Diet. Lond. 1809. Pearson's Synopsis, Lond.
1808. Peyer, Anat. Ventric., in Mangel, Bibl.
anat. Peyer, Mericologia, Basil. 1685. Philip's
Inquiry, (2d ed.) Lond. 1818. Pitcarrn, Dissert.
Edin. 1713. Pitcairn, Elem. Hags, 1718. Plenk,
Bromatologia, Vien. 1784. Prichard on the vital
principle, Lond. 1829. Pringle's Observalions,
(3d ed.) Lond. 1761. Prout's Abstracl of his
Gulstonian Lecture. Ditto, in Ann. Phil.vol. xiii.
xiv. Ditto, in Phil. Trans, for 1824. Ray's
Wisdom of God, Lond. 1717. Reaumur, in Mem.
Acad. pour 1752. Redi, Experien. d.vers. cose,
Firen. 1671. Richter, De Viet. Anim. Antiq.
Gott. 1761. Roget's Bridgewater Treatise, Lond.
1834. Rostan, Diet, de Med. I. i. Rousseau,
Anal. comp. du syst. dentaire, Par. 1827. Rullier,
Diet, de Med. t. xv. Ruysch, Opera, Amst. 1737.
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Amst. 1678. Serres, L'anat. et physiol. des dents,
Par. 1817. Serres, in Mem. Soc. d'Emul. I. viii.
Smith's Inlr. to Botany, Lond. 1807. Spallanzani's
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gestion, Gen. 1783. Stahl, Fund. Chym. Dogmat.
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1740. Vauquelin, in Ann. Chem. t. Ixxxi. Young's
Medical literature, Loud. 1813.

(J. Bostock.)

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

DIGESTIVE CANAL.

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

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

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

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

DIGESTIVE CANAL.

29

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

Fig. 4.

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

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

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

Fig. 5.

Fig. 6.

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

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

30

ECIIINODERMATA.

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

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

(For the higher forms of the alimentary canal
in all the separate classes of the animal king-
dom, see the names of the several classes from
the PORIFERA to the MAMMALIA, ANIMAL
KINGDOM, and the preceding article DIGES-
TION.)

( R. E. Grant.)

ECHINODERMATA, (e^w?, echinus—
IlittMt, corium,} Fr. Echinodermes. A class
of invertebrate animals belonging to the di-
vision Radiata or the Cycloneurose sub-king-
dom. The most familiar examples of them are
the common sea-urchin and star-fish.

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

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

Order I. ASTEROIDEA or STELLE-
RIDA.
Body depressed, divided into rays like a star,

or at least with prominent angles. Mouth

inferior, generally no anus.

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

Genus 1. ASTERIAS, (Jigs. 298 vol. i.
7-22.)

b. No grooves for the feet.

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

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

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

ECHINODERMATA.

31

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

Genus 5. ENCRINUS. Body supported
on a jointed stem. (With one ex-
ception the species are all fossil.)

Order II. ECH1MDA.
Body globular or ovoid, without rays ; skin

containing a calcareous shell ; anus distinct.

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

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

10-19.)
Genus 2. CIDARITES.

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

Genus

r

Anus on
the ventral
surface or"
the border.

3. GALERITES.

4. ECHINONEUS.

\. CASSIDULUS.
). NUCLEOLITES.

Rows of feet

not extending

^to the inferior

opening of the

shell.

Mouth and anus both ec-

Rows of feet
extending
from the anus
to the inferior
opening of the
jshell.

5. SCUTELLA.

6. CLYPEASTER.

_7.FlBULARIA.

Anus

above the
border or
dorsal. )
c. Plagyostoma.
centric.

Genus 10. ANANCHITES.
Genus 11. SPATAXGUS.
Order III. HOLOTHURLE.
Body oblong, (Jig. 34 vol. i.) coriaceous, with
the anus (/r) and mouth (a) at its opposite
extremities. Mouth surrounded with retrac-
tile, branched tentacula (o). Organ of re-
spiration a ramified tube (A,./, f), placed
within the body and opening at the anus.
Genus. HOLOTHURIA. (Jig. 34 p. 109,

vol. i. and Jig. 20.)

The genera Asterias, Echinus, and Holo-
thuria are those in which the internal struc-
ture has been most frequently and fully inves-
tigated ; they are therefore usually selected as
the leading examples in anatomical descriptions
of the Echinodermata, the peculiarities of other
genera being mentioned in so far as they have
been satisfactorily ascertained, and are of suffi-
cient importance to demand special notice.

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

a In the Asterias the integuments consist of,

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

Inferior view of Asterias rttbens: at A part of the
feet is removed.

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

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

ECHINODERMATA.

median line, and two smaller ones (6, i,)
placed laterally. On the sides of the ray the
calcareous substance is disposed, as it were, in
ribs (c, c, Jig. 9) ; these rise from the floor at
first nearly parallel with each other, and are con-
nected by cross bars, but on approaching the
upper part or roof of the ray they cross in all
directions and form an irregular network, the
intervals of which are occupied by softer inte-
gument. The ribs and bars are made up of
small pieces joined by plane but oblique sur-
faces, a mode of construction calculated to
admit of their being lengthened and shortened
upon one another, and thus to allow of the ca-
vity they surround being dilated and contracted.

Fig. 9.

Portion of a ray of Asterias rubens viewed laterally.

A broad calcareous disk is situated on the
upper surface of the body, in the angle be-
tween two of the rays, (Jigs. 12 and 16, z,) which
is connected internally with a singular organ
named by Tiedemann the sand canal, to be
afterwards described. The calcareous pieces
are of a homogeneous structure, without cells
or fibres ; they consist, according to Hatchett's
analysis, of carbonate of lime, with a smaller
proportion of phosphate of lime.

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

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

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

The appendages of the second kind are of a

very singular nature ; they have the appearance
of pincers or crabs' claws in miniature (Jig. 298,
c, 6, />, p. 615, vol. i.) and were described
by Miiller as parasitical animals under the
name of Pedicellaria. Monro gave the name
of antennae to analogous organs which are
found on the sea-urchin. They probably do
not exist in all species, for Tiedemann makes
no mention of them in his description of A.
auranliaca. In A. rubens they cover the
surface generally, and form dense groups round
the spines. Each consists of a soft stem
bearing at its summit, or (when branched) at
the point of each branch, a sort of forceps of
calcareous matter not unlike a crab's claw,
except that the two blades are equal and similar.
When the point of a fine needle is introduced
between the blades, which are for the most
part open in a fresh and vigorous specimen,
they instantly close and grasp it with consi-
derable force. The particular use of these
prehensile organs is not apparent ; their stem,
it may be remarked, is quite impervious.

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

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

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

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

ECHINODERMATA.

33

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

Fig. 10. A.

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

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

VOL. II.

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

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

Jfe.il.

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

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

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

D

34

ECHINODERMATA.

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

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

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

The principal locomotive organs of Echino-

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

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

Fig. 12.

ECHINODERMATA.

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

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

cutting it across, however, it is found to be
more complex in structure than appears exter-
nally, for it contains within, two convoluted
laminoe of the same nature as its calcareous
parietes (fig. \ 3). These laminae are rolled lon-
gitudinally; they rise conjointly or as one, from

Portion of the
canal of Asterias
rubens, magnified.

the internal surface of the
tube, pass inwardly a cer-
tain way, then separating
are rolled in opposite di-
rections; something after
the same manner as the
inferior turbinated bone of
the ox. These internal
laminae become more con-
voluted towards the upper
end, where at last they, as
well as the more external
part of the tube, join the
dorsal disk, appearing gra-
dually to become conti-
nuous with its substance.
The disk is perforated with numerous pores
which open into the tube. Tiedemann con-
ceives the function of the sand canal to be that
of secreting the earthy matter required for the
growth of the calcareous skeleton. Meek el
considered this view as very improbable, and
the description we have given does not tend to
corroborate it. We must confess ourselves
unable to offer more than mere conjecture as to
the use of this singular structure. If the fluid
contained in the feet and their vessels be sea-
vrater, (either pure or with an admixture of
organic particles,) which is probable from its
chemical composition, may it not be intro-1
duced and perhaps again discharged through
the pores of the disk and the calcareous tube,
the porous disk serving as a sort of filter to
exclude impurities ?

In the Echinus the feet are disposed in ver-
tical rows running from the anal orifice towards
the mouth; and the corresponding rows of
apertures (fig. 10, e, e,~) thus diverging from a
point have been compared to garden-walks,
and named ambulacra. In most cases the feet
extend all the way to the inferior opening of
the shell, but in some genera they stop short
before reaching this point. ' There are ten rows
disposed in five pairs. The tubular part of each
foot communicates with the interior of the shell
by two branches which pass through two aper-
tures. These branches in some species (as
E. sezatalis) communicate directly with the
canals which convey the fluid to the feet ; in
others (as E. esculentus) they open into a
plexus of vessels, by the intervention of which
they are connected with the canals. The plex-
uses of vessels alluded to are formed in leaf-
like membranes (fig. 14, d,d, representing two
of them magnified,) which are of equal num-

J%.14.

ber with the feet, and of course disposed in

D 2

36

ECHINODERMATA.

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

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

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

Fig. 15.

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

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

In Holothuriae the feet are sometimes scat-
tered over the whole surface of the body;
in other species (as H.pentactesJ they are
placed in five longitudinal and tolerably regular
rows ; while in others again they are confined
to the ventral surface, as in H. phuntapus,
where they form only three rows. The tubular
part (fig- 20, 6, &,) is in general very short,
and is connected with a simple vesicle inside.
The vessels of the feet arise from a circular
canal which surrounds the stomach near the
fore part of the body. One or sometimes two
large pyriform sacs (fig. 34, 6, p. 109, vol. i.)

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

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

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

a. In Asterias a short but dilatable gullet
leads to the stomach (figs. 16 and 22,^/J, which
occupies the central part of the animal, and
from the stomach a pair of lobulated coeca (g,
g, and i'', g', inflated,) pass into each ray.
The stou. ich is connected at various places
with the parietes of the body by ligamentous
bands; it is thin and membranous, soft and
corrugated on the internal surface, receiving
externally a covering of peritoneum, and con-
taining muscular fibres which are more obvious
towards the lower part, when it adjoins the
still more muscular oesophagus. Two or more
blind sacs (l)t branched in some species, open

ECIIINODERMATA.
Fig. 16.

37

Asterias rubens : three rays
d, d, a

—in the one, at A, caeca cut short to shew the vesicles of the feet,
one ovary, o; g, g, caeca, g' g', coeca inflated.

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

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

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

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

38

ECHINODEHMATA.

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

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

Fig. 17.

Fig. 18.

Dental apparatus of the Sea-urchin viewed
from above.

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

A, two sockets with teeth,
of Echinus esculentus.

B, single socket with
its tooth viewed on
the outside.

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

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

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

ECHINODERMATA.

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

The oesophagus (fig. 19, a,) rises through
the lantern, to which it is connected by fine
ligaments, and after a few curvatures termi-
nates in a wider part of the alimentary canal,
somewhat in the same way as the small intes-
tine joins the great in the human body. The
wider portion (6, 6,) of the canal turns twice
round the inside of the shell in a waving
manner, and terminates at the anus (c). In

. 19.

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

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

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

* Diet, des Sc. Nat. art. Owsin.

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

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

c. The alimentary canal of the Holothuria is

Fig. 20.

Holothuria tubulosa : alimentary canal and blood-
vessels.
The respiratory organ, r, c, is cut short.

40

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

ECHINODERMATA.

Fig. 21.

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

part as the stomach. In H. pentactes, the part each group the fibrous membrane forming the
immediately succeeding the oesophagus and ex-
tending nearly to the first flexure, is somewhat
cellular and at the same time wider, but thin-
ner in its coats than the rest of the canal ;
this part is considered to be the stomach by
Meckel,

It is a singular fact, which it appears was

-_j*_11 T»1- ,1 . I • /

wall of the body presents on its inside a shal-
low pit (fig. 21, a; Jig. 298, vol. i. e ; fig. \ 6, s, *,)
perforated with holes, through which the tubes
communicate with the internal cavity. The
tubes are formed externally of the superficial
layer of the skin, and are lined in the inside
by a prolongation of the peritoneal membrane.

first noticed by Redi, that several species of This membrane lines the parietes of the body,

Holothuria, on being taken from the sea and
put into a vessel of sea-water, discharge their
intestine and part of the respiratory organ
through the anus. This operation is effected
by repeated contractions of the cutaneous
muscles, and some naturalists are disposed to
regard it as a voluntary act.

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

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

and is reflected over the contained parts; at
least it covers the stomach and co2ca, and pro-
bably also the ovaries and vesicles of the feet ;
opposite the perforated pits it sends prolonga-
tions (b, 6,) through the holes into the tubes,
as may be easily seen on stripping off a portion
of it.

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

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

ECHINODERMATA.

41

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

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

c. The respiratory organ of Holothuria (fig.
34,./, fj h, p. 109, vol. i.) has some resem-
blance in form to that of air-breathing animals.
It is a very long membranous sac, placed
within the body, which opens into the cloaca
near the rectum and extends forwards from
thence nearly the whole length of the body,
either single, or (as in Holothuria tubulosa)
divided into two main branches (fig. 20, c, c,
cut short, fig. 34, J\f9 p. 109, vol. i.), which
in the vicinitv of the cloaca are joined by a

short common stem. One of these branches
is intimately connected by bloodvessels to the
intestine, the other by muscular fasciculi to
the parietes of the body. The sac, whether
single or bifid, gives off a great many lateral
branches, \vhich after successive divisions ter-
minate in shut or blind extremities. Both
stem and branches contain distinct circular and
longitudinal muscular fibres, and contract on
being irritated. In the act of respiration sea-
water is drawn into and expelled from this
organ, and its entrance and exit, which may
be readily seen at the cloaca, occur in some
species so often as once, twice, or even three
times in a minute. The alternate inhalation
and expulsion of the fluid are effected partly
by the action of the muscular parietes of the
body, but principally, it would appear, by the
muscular fibres of the organ itself, for Tiede-
mann observed the process still to go on,
though with diminished activity, when the
animal was cut open and the organ exposed.
Cuvier states that the sac in some species is
without branches.

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

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

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

42

ECHINODERMATA.

Fig. 22.

Asterias aurantiaca opened from above.

A, ray with the coeca<jr, <7,in their place. B, coeca removed ; vesicles of feet d, seen. C, vesicles of
feet removed to shew the calcareous segments of the ray. D, skin forming roof of the body
and rays A, B, C, raised j vessels seen on its inner surface with collapsed stomach, f, &c.

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

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

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

ECHIHODERMATA.

43

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

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

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

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

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

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

44

ECHINODERMATA.

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

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

Fig. 23.

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

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

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

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

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

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

* Grant's Comparative Anatomy, p. 184.
t Miiller's Archiv flic Anatomic, Physiologic,
&c, 1834. p. 577.

$ Comparative Anatomy, p. 184.

ECHINODERMATA.

45

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

a. The ovaries of Asterias seem to vary in
number according to the species. In A. rubens
and aurantiuca there are ten, two being situated
in each ray, above the vesicles of the feet.
Each of these organs consists in the former
species of an oblong cluster of ramified tubes,
(Jigs.ll and 1 6, o, and ato', cut short), proceeding
all from a single stem by which the organ is
fixed, and terminating in round vesicular dila-
tations. In A. aurantiaca the tubes are not
all connected by a single stem, but form about
twenty fasciculi, each of which has a distinct
attachment (jig. 22, o, o).

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

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

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

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

* Fauna Groenlandica, p. 368.

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

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

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

BIBLIOGRAPHY.— Kleinius, Naturalis dispositio

* Fauna Groenlandica, p. 353.
t Reaumur, Memoires pour servir a 1'histoire
des insectes, tome vi. preface, page Ix. sq.

46

EDENTATA.

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

(W. Sharpey.)

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

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

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

Fig. 24.

Skeleton of tlie Sloth.
Fig. 25.

Skeleton of the Ant-eater.

EDENTATA.

Fig. 26.

47

Skeleton of the Armadillo.
Fig. 27.

Skeleton of the Hants.
Fig. 28.

Skeleton of the Megatherium.

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

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

48

EDENTATA.

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

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

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

Fig. 29.

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

Fig. 31.

Head of the Ant-eater.

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

Fig. 32.

Head of the Sloth.

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

Fig. 30.

Head of the Armadillo.

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

EDENTATA.

49

Fig. 33.

Fig. 34.

Head of the Megatherium.

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

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

VOL. II.

Neck of the Sloth.

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

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

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

50

EDENTATA.

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

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

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

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

Fig. 35.

Hand of the Sloth.

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

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

EDENTATA.

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

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

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

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

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

Fig. 36.

Hand of the Ant-eater.

E 2

EDENTATA.

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

Fig. 37.

Hand of the Gigantic Armadillo.

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

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

derate length, but large and strong; and an
elevated crest, arising from the great trochanter,
extends nearly the whole length of the bone.
In the Ant-eaters and the Megatherium, it is
particularly broad and flattened, and the greater
and lesser trochanters are not particularly pro-
minent. In the genus Dasypus the great tro-
chanter on the contrary is of great size, and
from the middle of its outer margin arises a
large process which is directed outwards. The
tibia zndjibula in the latter genus are extremely
broad, arched, and anchylosed at both extremi-
ties. In the Ant-eaters, on the other hand, these
bones are of the ordinary form, and have no
osseous union. In the Megatherium they are
united by the superior third of their length, and
closely in contact at the lower part ; they are
both short and extremely thick, particularly the
tibia. The tarsus is composed in the two-toed
Ant-eaters of at least eight distinct bones, the
largest of which is a supernumerary
bone, situated at the inner part of the
foot, upon the scaphoid; it extends back-
wards as far as the tuberosity of the
os calcis, and thus forms a broad base
to the posterior part of the sole of the
foot. The Myrmecophaga jubata has
also a supernumerary bone, but of
smaller dimensions ; but the Armadillos
and Orycteropus have but the seven or-
dinary bones of the tarsus. The metatarsal
bones and the toes are probably invariably five
throughout the Edentata proper; the toes of
the posterior extremity offer few peculiarities of
any consequence. Both the anterior and poste-
rior feet of the Megatherium are peculiar in their
structure. In the former, those fingers which
are completely formed are the three middle
ones, the little finger being rudimentary, and
the thumb having no claw. The ungueal pha-
langes of the three former are enormously deve-
loped, principally as regards the bony enve-
lope for the base of the claw; the size and
thickness of which indicate that the claws
themselves must have been of great size and
immense strength, and have afforded powerful
implements for tearing up the suiface of the
ground in search of roots. On the hinder
foot, there is a single toe of a similar con-
struction, which is the third ; the fourth and
fifth, although of considerable size, bore no
claws. This enormous extinct animal is cer-
tainly among the most extraordinary produc-
tions of the ancient world. Of dimensions the
most unwieldy, and with a skeleton as solid as
that of the most enormous amongst the Pachy-
dennata, we find a cranium, and especially
teeth, which exhibit a very near relation to those
of the Sloth, and members which are no less
remarkably allied to the Ant-eaters and the Ar-
madillos. However the difference in bulk may
appear at first sight to interfere with the idea of
these affinities, and however difficult it may be
at once to reconcile the relation between a
small active animal like the Armadillo, or
an inhabitant of trees like the Sloth, and
this enormous and unwieldy tenant of the
earth's earlier surface, the affinities are neither
less true nor more probable than those which
subsist between the light rabbit-like hyrax

EDENTATA.

53

and the ponderous rhinoceros of the present
world.

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

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

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

38.

Skekton of the Chlamyphorus truncatus.

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

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

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

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

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

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

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

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

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

54

EDENTATA.

Fig. 39.

Stomach of the Sloth.

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

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

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

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

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

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

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

ELASTICITY

55

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

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

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

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

For BIBLIOGRAPHY, see that of MAMMALIA.

(T.Eell.)

ELASTICITY (Germ. Springkraft, Fe-
derkrcift) is that property of natural bodies in
virtue of which they admit of change either of
size or form from the application of external
force, resuming, upon the suspension of that
force, their proper shape or volume.

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

56

ELASTICITY.

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

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

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

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

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

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

ELASTICITY.

57

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

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

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

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

58

ELASTICITY.

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

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

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

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

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

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

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

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

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

ELASTICITY.

59

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

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

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

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

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

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

60

ELASTICITY.

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

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

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

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

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

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

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

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

ELASTICITY.

61

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

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

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

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

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

62

REGION OF THE ELBOW.

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

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

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

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

For the BIBLIOGRAPHY of this article, see that
of FIBROUS TISSUE and MUSCLE.

(John E. Brenan.)

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

REGION OF THE ELBOW.

63

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

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

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

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

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

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

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

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

64

REGION OF THE ELBOW.

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

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

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

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

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

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

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

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

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

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

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

ARTICULATION OF THE ELBOW.

65

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

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

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

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

(J. Hart.)

ELBOW (ARTICULATION OF THE),

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

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

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

F

66

ARTICULATION OF THE ELBOW.

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

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

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

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

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

* Handbuch der menschlichen Anatomic, band
ii.

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

The synovial capsule, having covered the ar-
ticular surface of the humerus, ascends above
this surface as high as an irregular continuous
line, including the two anterior articular fossae
in front, the posterior articular fossa behind,
and limited by the bases of the condyles late-
rally ; at the level of this line the capsule is re-
flected from the humerus, and descends on the
internal surfaces of the fibrous ligaments to be
expanded over the articular surfaces of the
radius and ulna, to the cartilaginous coverings
of which it adheres in the same intimate man-
ner as to that of the articular surface of the
humerus ; the portion of it corresponding to
the radius descends within the annular liga-
ment, below which it is reflected on the neck,
and thence continued over the head of that
bone; while it becomes attached to the ulna at
the line which circumscribes the greater and
lesser sigmoid cavities over the surfaces of
which it is extended ; this capsule, which is
rathe)1 tense where it lines the lateral ligaments,
is flaccid and sacculated anteriorly and poste-
riorly, so as not to interfere with the freedom of
flexion and extension of the elbow : below the
margin of the annular ligament and before it
is attached to the neck of the radius, it forms a
cul-de-sac so loose as to permit the rotatory
motions of that bone to be executed without
restraint.

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

ABNORMAL CONDITION OF THE ELBOW-JOINT.

67

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

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

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

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

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

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

In extension, the o'ecranon, ascending above
the level of the condoles, is received into the
posterior articular fossa, displacing the adipose
substance which previously occupied that fossa,

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

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

(J. Hart.)

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

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

68

ABNORMAL CONDITION OF THE ELBOW-JOINT.

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

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

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

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

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

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

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

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

* See plate \xv'\.Jig. 1, of Sir A. Cooper's work
on Fractures and Dislocations.

ABNORMAL CONDITION OF THE ELBOW-JOINT.

Fig. 40.

Fracture and retraction of the outer condyle of the humerus.

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

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

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

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

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

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

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

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

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

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

70

ABNORMAL CONDITION OF THE ELBOW-JOINT.

Fig. 41.

Luxation of both bones backwards,

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

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

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

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

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

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

ABNORMAL CONDITION OF THE ELBOW-JOINT.

71

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

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

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

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

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

Fig. 42.

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

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

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

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

72

ABNORMAL CONDITION OF THE ELBOW-JOINT.

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

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

3. Under the head of lateral luxations of
the elbow-joint, Sir A. Cooper has described
accidents which might perhaps be more cor-
rectly designated — a, complete luxation of the
bones of the fore-arm at the elbow backwards
and outwards; 6, complete luxation of the
bones of the fore-arm at the elbow backwards
and inwards.

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

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

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

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

5. Luxations of the upper extremity of the
radius from the humerus and ulna. — When we
look into the best books we possess for infor-
mation on this subject, we must be struck with
the remarkable discrepancy of the opinions we
find expressed by the authors. Thus, upon
the subject of luxation forwards of the radius,
we find the celebrated Boyer stating that he
doubts such a luxation can occur without being
complicated with a fracture. Sanson states that
this luxation forwards has never been observed,
and moreover advances what he considers as
anatomical and physiological explanations, to
show the impossibility of such an occurrence-
Sir A. Cooper, on the contrary, gives six
examples of the luxation of the upper extre-
mity of the radius forwards. The French
writers state of the luxation of this extremity
of the radius backwards, that although it is
rare it has been many times witnessed, while
Sir A. Cooper, alluding to this luxation back-
wards, says, " this is an accident which I have
never seen in the living," but he gives an
anatomical account of the appearances found
in a subject, the history of which was unknown,
brought into St. Thomas's Hospital for dissec-
tion. Having thus stated the different opinions
of authors upon this subject, we shall proceed
to give an account of — a, the luxation of the
upper extremity of the radius forwards ; 6, of
its luxation laterally and upwards ; c, of its
luxation backwards ; d, of its sub-luxation ;
e, of its congenital luxation backwards.

* Sec plate xxiv.yZj/. 2, in Sir A. Cooper's work.

ABNORMAL CONDITION OF THE ELBOW-JOINT.

73

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

Fig. 43.

Luxation of the radius forwards.

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

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

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

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

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

74

ABNORMAL CONDITION OF THE ELBOW-JOINT.

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

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

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

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

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

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

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

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

ABNORMAL CONDITION OF THE ELBOW-JOINT.

75

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

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

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

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

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

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

ABNORMAL CONDITION OF THE ELBOW-JOINT.

and ulna are, in their Fig. 44.

natural state, on an even

line with each other.

There is scarcely any

interosseous interval, the

bones seem so closely

connected with each other.

Indeed, from the inspec-

tion of this preparation,

we may justly infer that

the fore-arm during life

had remained much in

a state of semiflexion on

the arm, and of rigid

pronation, and that the

movement of supination

was nearly impracticable.

This defective formation,

or atrophy of the capitu-

lum and increased deve-

lopement of the trochlea

of the humerus, which

was so formed to ac-

commodate itself to the

unusual breadth acquired

by the coronoid process

and the whole of the

ulna, must not be con-

sidered unprecedented.

We find, by referring to

the beautiful work of

Sandifort, (the Museum

Anatomicum, table ciii.

fig. 3,) a case similar to

the above delineated

(Jig- 45). In referring

to it, the author states

that the bones of the

fore-arm were anchylosed,

that the form of the ca-

pitulum Was lost, tto

the head of the radius

was luxated completely

backwards, and that the

ulna alone remained in

articulation with the hu-

merus; the parallelism

between these two cases

will be still more fully

seen, when, speaking of

the lower articular extre-

mity of the humerus, we

find that he says,"Figura

ergocapituliperiit.Rotula

unica, sed major forma-

tur;" and of the ulna,

" insignem acquisivit am-

plitudinem et totam infe-

riorem ossis humeri par-

tern admittere potuit.

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

irocMta enlarged -no
capitulum.

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

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

For our part we cannot
see in these pathological ob-
servations any thing to con-
vince us that any one of the
cases alluded to was an old
luxation originally produced
by accident or disease. Sup-
pose, for argument sake, it
be admitted that, from long
disease, the form of the
, capitulum was altogether
IS K «*» the radi«s was no
it was found as longer in contact with it, and
long as the ulna, that the acquired breadth of

Fig. 46.

ABNORMAL CONDITION OF THE ELBOW-JOINT.

77

the sigmoid cavity of the ulna was the result of
a natural effort to compensate for the loss of
strength the joint suffered from the dislocation
of the radius. Still, supposing it possible that
the surface of the capitulum of the htimerus
could be so completely removed, under such
circumstances, as we find it was in the cases of
vfhichjigs. 44 and 45 are delineations, we may
ask, is it likely, from accident or disease,
that both elbow-joints should be similarly
arfected, as they were in Dupuytren's cases.
Another circumstance in our mind cannot be
accounted for, unless by supposing these cases
congenital, . namely, the alteration and great
elongation of the neck of the radius. " L'ex-
tremite superieure de chaque radius avail
abandonne sa situation naturelle, se trouvait
place derriere 1'extremite inferieure de 1'hu-
merus, et depassait cette extremite d'un
pouce ciu moins. Cette disposition etait ab-
solument la meme de chaque cote du corps."
We know of no process which could take
place in the head and neck of the radius after
it had been dislocated, which could satis-
factorily account for the elongation of the
radius, which has been remarked in these
cases. While looking on them as congenital,
we need not be surprised at it ; for we have
known the neck of the femur elongated and
atrophied, in the case of congenital luxation
of the femur, and have very frequently seen
the lower extremity of the ulna exceed in length
by half an inch the corresponding extremity
of the radius ; and these were cases in which
no doubt could be entertained that they were
congenital.

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

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

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

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

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

ABNORMAL CONDITION OF THE ELBOW-JOINT.

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

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

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

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

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

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

ABNORMAL CONDITION OF THE ELBOW-JOINT.

79

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

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

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

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

80

ABNORMAL CONDITION OF THE ELBOW-JOINT.

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

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

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

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

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

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

ANIMAL ELECTRICITY.

81

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

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

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

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

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

VOL. If.

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

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

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

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

unimaculata. Risso.

marmorata. Ditto.

Galvanii. Ditto.

Gymnotus elect ricus.

Trich iurus elect ricus.

JMalapterurus electricus.

Tetraodon electricus.

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

* Phil. Trans. 1774.

82

ANIMAL ELECTRICITY.

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

It must be regarded as an extremely interest-

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

% Kirby and Spence's Entomol. vol. i. 110.
<S Naturgesch. von Chili. S. 175.
(I Gesch. dcs Konigr. Chili. S. 63.
T Treviranns, Biologie. V. 144.

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

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

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

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

ANIMAL ELECTRICITY.

83

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

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

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

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

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

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

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

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

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

G 2

84

ANIMAL ELECTRICITY.

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

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

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

* Phil. Trans. 1775, 2.

t Phil. Trans. 1773, 467.

J Phil. Trans. 1829, 15.

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

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

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

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

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

ANIMAL ELECTRICITY.

85

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

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

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

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

* Mem. de 1'Acad. de Berlin, 1770.

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

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

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

* Biologie, v. 145.

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

86

ANIMAL ELECTRICITY.

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

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

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

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

* Pouillet, Elom. de Phys. i. 773.
t Phil. Trans. 1829.
J Phil. Trans. 1832.
$ Phil. Trans. 1834.

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

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

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

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

ANIMAL ELECTRICITY.

87

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

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

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

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

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

* Phil. Trans. 1834.

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

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

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

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

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

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

* Phil. Trans. 1816.
t Phil. Trans. 1834. 120.

t Handbuch der Physiol. des Menschen. Co-
blenz. 1833.

88

ANIMAL ELECTRICITY.

with their large nerves, are the sole means
employed in bringing this mysterious agent
under the control of the animal's volition.
They are therefore well worthy of an attentive
examination.

i. The electrical organs in the torpedo. —
The torpedo is a flat fish, possessing the same
general appearance and structure as the rays,
and classed along with them in zoological sys-
tems. The electrical organs occupy a large

coverings are discovered investing the electrical
organs. The outer one has longitudinal fibres,
which are rather loosely adherent, and, around
the margins of the organs, seem to inosculate
with the skin. The inner fascia is of consider-
able density, forms the immediate tunic of the
electric columns, and sends processes down
between them to form their partitions. Through-
out their whole extent, the essential part of the
electrical organs is formed by a whitish soft

Fig. 47.

Upper surface of electrical organ of left side.

A, common integuments. B, branchial opening. C, eye.
sected off from the electrical organ, and turned outwards.
G G, the upper surface of electrical organ.

D, situation of the gills. E E, skin dis-
F, part of the skin which covered the gills.

part of the broad expansions of the body,
which in the other allied fishes are formed
only by the lateral fins. They form two sepa-
rate masses, one on either side of the head and
gills, extending outwardly to the cartilaginous
margins of the great fins; and, posteriorly, to
the cartilage which separates the thoracic from
the abdominal cavity. Their form and the
honey-comb embossments of their surfaces can
be distinguished through the skin both of the
dorsal and ventral aspects. The common inte-
guments being removed, two strong fascial

pulp, divided into numerous pentagonal prisms
by the fascial processes just mentioned. These
lie close together, parallel with one another,
and perpendicularly between the dorsal and
ventral surfaces of the fish, so that their extre-
mities are separated from these surfaces only
by their fascial and the common integuments.
When these are removed, the columns present
something of the appearance of a honey-comb.
The columns are longest next to the head and
gills, and thence gradually diminish outwardly,
until, on the external margin, they are only

ANIMAL ELECTRICITY.

89

about one-sixth of the length of the internal
ones. In a fish described by John Hunter,*
of which the whole electrical organ was about
five inches in length, the longest column was
about one inch and a half, and the -shortest
about one-fourth of an inch in length. In the
same h'sh the average diameter of each column
was about two-tenths of an inch. In a fish
from the Mediterranean, thirteen inches and a
half in length, and about seven inches in
breadth, (which, through the kindness of Dr.
Allen Thomson, we have had an opportunity
of examining in detail,) the length of the
longest columns is one inch, and that of the
shortest about three-tenths of an inch. Most
of these columns are either irregular pentagons,
or irregular hexagons ; a few are nearly tetra-
gonal. They are united to one another by
short but strong fibres, and by a reticular
expansion of tendinous threads spread through
them. Their number varies considerably ac-
cording to the age of the fish. Hunter con-
jectured that a few new columns are added
every year to the circumference of the organ.
In one of the largest fish that has yet been
particularly examined, which was four feet and
a half in length, the number of columns in
one electrical organ was 1182. Mr. Hunter
found 470 in each organ in a fish of ordinary
size. Mr. Hunter described each column as
beinff divided into numerous distinct compart-
ments by delicate membranous partitions,
placed horizontally, at very short distances
from each other. The interstices between them
appeared to him to contain a fluid. He found
the partitions in several places adhering to one
another by bloodvessels; and all, throughout
their whole extent, attached to the inside of
the column by a fine cellular membrane. In
a column of one inch in length, he reckoned
150 partitions, and it appeared to him that
their number is the same within the same space
in all the columns.f Hence, he thought it
likely that " the increase in the length of a
column, during the growth of the animal, does
not enlarge the distance between each partition
in proportion to that growth, but that new
partitions are formed and added to the extre-
mity of the column from the fascia."

The partitions are covered with fine network
of arteries, veins, and nerves. According to
Hunter, " they are very vascular." He described
the numerous arterial branches which ramify
on the walls of the columns as " sending in-
wards from the circumference all around, on
each partition, small arteries which anastomose
upon it, and passing also from one to the other,
unite with the vessels of the adjacent parti-
tions." The partitions themselves are so deli-
cate as not to admit of being satisfactorily
examined in the fresh fish : (all Hunter's obser-
vations were made upon fish that had been
preserved in spirits, by which, doubtless, the
delicate membranes were rendered more opaque,
and therefore more easily visible.) In point

* Phil. Trans. 1773, 481.

t Desmoulins and Majendie say that they found
only seven or eight partitions in each column.
Anat. des Syst. Nerv. ii. 378.

of fact, Dr. Davy has never seen them in the
course of the numerous dissections which he
has made of the electrical organs in fish recently
taken ; whereas, in specimens sent hither by
him, preserved in spirits, Dr. Allen Thomson
and the writer of this article have satisfactorily
ascertained their existence and structure as
described by Hunter. Dr. Davy says, " when
I have examined with a single lens, which
magnifies more than 200 times, a column of
the electrical organs, it has not exhibited any
regular structure ; it has appeared as a homo-
geneous mass, with a few fibres passing into it
in irregular directions, which were probably
nervous fibres."* However, after having im-
mersed the organs in boiling water, Dr. Davy
has occasionally seen something like a lami-
nated structure within the column. Rudolphi
satisfied himself of the division of the columns
by membranous partitions, and further, that
each partition is supplied with a distinct nerve.-f-
In a memoir on the comparative anatomy of
the Torpedo, Gymnotus, and Silurus, Geoffrey
described J the columns as being filled with a
semifluid matter composed of gelatine and
albumen.

A large quantity of fluid enters into the
composition of the general mass of the elec-
trical organs. Dr. Davy has found that they
lose more by drying than any other part of the
fish— nearly 93 per cent. ; while the soft parts
in general, including the electrical organs, lose
only 84.5 per cent.§ He believes that the fluids
of the organs hold various substances in solution,
but the exact nature and proportions of them
have not been ascertained. We are indebted
to the same indefatigable observer for an ac-
count of the specific gravity of the electrical
organs. He found it to be very low compared
with that of the truly muscular parts of the
fish, — namely, 1.026, to water as 1.000, while
that of a part of the abdominal muscles of the
same full-grown fish was 1.058, and of the
dorsal muscles 1.065. In a fish eight inches
long, five inches across the widest part, and
which weighed 2065 grains entire, the electric
organs together weighed 302 grains, the liver
only 105 grains.

No contraction has ever been seen in the
electrical organs of living fish under the stimu-
lus of the strongest excitants, not even under
that of galvanism; so that, although what
appear to be tendinous threads are spread
amongst and over the columns, we have no
reason to suppose that any muscular tissue
enters into their composition. But, in all
directions, they are exposed to the pressure of

* Phil. Trans. 1832. 259.

t Abhandl. der Acad. der Wissensch. in Berlin.
1820. 224.

* Ann. du Mus. No. 5.

§ The smallest torpedo employed by Dr. Davy
in his experiments weighed 410 grains, and con-
tained only 48 grains of solid matter; its elec-
trical organs weighed 150 grains, and contained
only 14 grains of solid matter; yet this small mass
gave sharp shocks, converted needles into magnets,
affected distinctly the multiplier, and acted as a
chemical agent. " A priori, how inconceivable
that these effects could be so produced!"

90

ANIMAL ELECTRICITY.

strong muscles, such as are plainly designed to
compress them. Some of these are inserted into
the marginal cartilages of the fins; and there is a
set of very powerful ones, arranged in a cruci-
form manner on the ventral surface, so placed
as to compress the electrical organs most strongly
during their contraction. Dr. Davy remarks,
" It is only necessary to compare these muscles
as they exist in the torpedo with the same in
any other species of ray to be convinced that
they are adequate to, and designed for, the
compression of the batteries."

Some observers, as John Hunter, state that a
large proportion of blood circulates through the
electrical organs. Girardi found the torpedo
much more full of blood than the other rays.*
But Dr. Davy says, that there are very few
vessels containing red blood in the organs them-
selves; although their tegumentary coverings
and the adjoining mucous system are highly
vascular. The arteries of the organs are
branches from the arteries of the gills ; their
veins run between the gills direct to the auricle.
The temperature of the electrical organs is not
at all higher than that of other parts of the fish.

All anatomists who have examined the torpedo
have had their attention much arrested by the
great size of the nerves distributed to the electri-
cal organs. These consist of three principal
trunks, all arising immediately from the cerebro-
spinal system. The two anterior trunks are re-
garded by Desmoulins and Majendief as
portions of the fifth pair of nerves, and the third
as a branch of the eighth pair. But the first
electrical nerve seems to have an origin altogether
distinct from the root of what is unquestionably
the main portion of the fifth pair, although it
certainly is in very close proximity with it, and,
in passing out of the cranium, the two nerves
seem to be in some degree united for a short
space. Immediately beyond this point of union,
the electrical nerve sends a soft twig to a small
cavity within the adjoining cartilage, (which Dr.
Davy thinks is the ear,) and then divides into
three small branches, and two large ones. One
of the small branches goes to the gills, another
to the neighbouring muscles, and the third to
the mouth. The first of the large branches runs
along the outer margin of the electrical organ,
advancing first anteriorly, then going round to
the posterior part of its circumference, and
losing itself in the mucous glands of the tegu-
mentary system, without sending a single twig
into the electrical organ itself. The other great
branch is inferior to the former in position, but
much more voluminous ; it enters the electrical
organ, and is ramified through its anterior third
part, passing between its columns, and giving
offnumerous twigs for the supply of the walls of
the columns, and the partitions, on which it
terminates ; some of which pass even into the
gelatinous matter with which the columns are
filled. This branch, from its very origin, has
all its fibres separated, isolated, and parallel,
held together only by cellular tissue, which
also forms a kind of membranous sheath around

Mem. della Soc. Ital. iii. 553.
Anat. Comp. des Syst, nerv.

the nerve. Just as it reaches the organ, it is
divided horizontally into two portions, one of
which runs near the upper surface, the other on
the plane between the lower and middle thirds
of the thickness of the organ.

When examined with a high magnifying
power, the minute branches of the electrical
nerves present a dotted appearance, showing as
if the medullary substance were arranged within
the sheath, not in a continuous line, but in a
succession of small portions with a little space
between each.*

The second electrical nerve rises a little be-
hind the former. After leaving the cranium, it
divides into two large branches, which, with the
exception of a few twigs which go to the gills,
are wholly distributed in the middle third of
the electrical organs, in the same manner as the
first pair.

The third electrical nerve arises from the brain
close to the second, from which, however, it is
separated by a thin cartilaginous plate. The
greater portion of it goes to the electrical organ,
and is distributed through its posterior third. It
also supplies part of the gills, the gullet, the sto-
mach, and the tail. Dr. Davy says it appeared
to him that the branch of this nerve which goes
to the stomach is the principal nerve of that
organ : it is spread over its great arch.f The
same observer also points out as deserving of
particular attention, a very large plexus of nerves
formed by a union of the anterior and posterior
cervical nerves, of the former of which there are
seventeen on either side, and only fourteen of
the latter. This plexus presents itself as a
single trunk just below the transverse cartilage
that divides the thoracic from the abdominal
cavity. It sends a recurrent branch to the
muscles and skin of the under surface of the
thorax; but the larger portion is distributed
upon the pectoral fin and the neighbouring
parts. The motive and sentient powers of the
muscles and integuments connected with the
electrical organs seem to depend on this
plexus.

The only other peculiarity of structure in the
torpedo which can be supposed to be in any
way connected with its electrical power, is in
the system of mucous ducts, which is much
more fully developed in it than in any other ray
with which we are acquainted. It consists of
numerous groups of glands arranged chiefly
around the electrical organs ; and of tubes con-
nected with these, having strong and dense
coats, filled with a thick mucus secreted by the
glands. The tubes open chiefly on the dorsal
surface of the skin, and pour out the mucus,

* Dr. John Davy, Phil. Trans. 1834.

t On this subject, Dr. Davy remarks — " It is an
interesting fact that the nerves of the stomach are
derived from those supplying the electrical organs.
Perhaps superfluous electricity, when not required
for the defence of the animal, may be directed to
this organ to promote digestion. In the instance of
a fish which I had in my possession alive many days,
and which was frequently excited to give shocks, di-
gestion appeared to have been completely arrested;
when it died, a small fish was found in its stomach,
much in the same state as when it was swallowed —
no portion of it had been dissolved."

ANIMAL ELECTRICITY.
Fig. 48.

91

The right electrical organ divided horixontatty at the place where the nerves enter, the upper half

being turned outwards.

A A, The first or anterior electrical nerve.

B B, The second or middle nerve arising behind the gill.

C C, The anterior branch of the third nerve arising behind the second gill.

D D, The posterior branch of the third nerve arising behind the third giU.

which, probably, serves as a medium of com-
munication between the electrical organs ; being,
apparently, a better conductor of electricity
than either the naked skin or salt water.*

With regard to the development of the elec-
trical organs, it appears that, in the earliest
stages of foetal growth, they cannot be seen. In
a foetus of about seven-tenths of an inch in
length, Dr. Davy found neither electrical organs
nor fins. In another, more than one inch long,
the organs were beginning to appear, and the
roots of the electrical nerves were visible,
although the brain could not be seen. In this
stage, the external branchial filaments were
about six-tenths of an inch in length, and pre-

* Davy, Phil. Trans. 1832. Also Annales du
Mas. no. v., in which E. Geoffroy endeavoured to
show that the common mucous system of rays is
absent in the torpedo, and that its place is supplied
by the columns of the electrical organs, which he
believed to be analogous to the mucous ducts.

sented a very remarkable appearance. In a
foetus of two inches and a half long, the electrical
organs were distinctly formed, and the branchial
filaments still long. These filaments Dr. Davy
supposes to be destined to absorb matter for the
formation of the electrical organs, and, perhaps,
the gills and adjoining mucous glands. They
are most numerous and of greatest length while
the electrical organs are forming, appearing just
before these organs begin to be developed, and
being removed when they are tolerably com-
plete.— In no other allied fishes is there the
same " elaborate apparatus of filaments;"
where they do exist, they are less numerous and
very much shorter.

2. The electrical organs in the Gymnotus. —
This fish has a general resemblance in form to
the common eel. Its electrical organs occupy
nearly one-third of its whole bulk. They are
formed by two series of tendinous membranes ;
one of which consists of horizontal plates, run-

ANIMAL ELECTRICITY.

ning from the abdominal cavity towards the tail,
placed one above another with short distances
between them ; the other of perpendicular plates,
forming, along with the other series, small quad-
rangular cells, which are filled with a semi-gela-
tinous transparent substance. This structure is
divided longitudinally into two pairs of distinct
organs, one considerably larger than the other.
The greater pair (k k, fig. 49) lies above the
other, and immediately beneath the long mus-
cles of the tail. They are separated from one

another by part of these muscles, by the air-
bladder, and by a central membranous partition.
They occupy a large portion of the lower and
lateral parts of the body, and are covered exter-
nally only by the common integuments. The
smaller pair are covered also by the muscles of
the caudal fin. Both pairs of organs are some-
what angular in their transverse section, trun-
cated anteriorly, tapering towards the tail. In
the Gymnotus dissected by'John Hunter,* which
was about two feet four inches long, the large

Fig. 49.

The surface of the electrical organs of the Gymnotus, on the right side, after removal of the integuments.

a, the lower jaw. b, the abdomen, c, anus, d, pectoral fin. e, dorsal surface of fish. //, anal
fin. g g, skin turned back, h h, lateral muscles of the anal fin turned back with the skin, to expose
the small electrical organ, i, part of this muscle left in its place, k k, the large electrical organ. / I,
the small electrical organ, m in, the substance which divides the large organ from the small, n, a
space from which the partition is removed.

Fig. 50.

A transverse section of the Gymnotus.

a, the surface of the side of the fish, b, the anal fin. c c,
cut ends of the dorsal muscles, d, cavity of the air-bladder.
e, body of the spine, f, spinal marrow, g, aorta and vena
cava. h h, cut ends of the two large electrical organs, i i,
cut ends of the two small organs, h, partition between the
two organs.

organ of one side was about one inch
and one quarter in breadth at its
thickest part, and in this space there
were thirty-four longitudinal septa.
(In a specimen examined by Dr.
Knox, there were thirty-one of these
septa.f) The smaller organ in the
same fish was about half an inch in
breadth, and contained fourteen septa,
which were slightly waved. The per-
pendicular or transverse membranes
are placed much more closely toge-
ther than those of the other series.
John Hunter and Dr. Knox counted
two hundred and forty of them in
an inch. They are of a softer texture
than the longitudinal plates. It ap-
pears probable (as Hunter suggested)
that these septa, longitudinal and
transverse, answer the same purpose
as the columns in the torpedo. La-
cepede calculated that the discharg-
ing surface of these organs in a fish
four feet in length is, at least, one
hundred and twenty-three square feet
in extent; while in a torpedo of ordi-
nary size, the discharging surface is
only about fifty-eight feet square.

The nerves of the electrical organs
of the Gymnotus are derived from the
spinal marrow alone. They are very
large and numerous, and are divided
into very fine twigs on the cells of the
organs. Dr. Knox counted fifteen
nervous branches distributed to each
inch of the organ. He describes
them as being flattened like the ci-
liary nerves of Mammalia. Each

* Phil. Trans. Ixv. 1775.

t Edin. Journ. of Science, i. 96. 1824.

ANIMAL ELECTRICITY.

93

nerve is, for the most part, divided into five
distinct branches before entering the electrical
organs; and these are again subdivided into,
at least, as many branches as there are longi-
tudinal septa. Rudolphi describes a nerve
formed from branches of the fifth pair and
sympathetic, which runs beneath the lateral
line, over the surface of the electrical organs,
but does not enter them. This has, by some,
been supposed to be an electrical nerve, but
without sufficient reason.*

3. The electrical organs in the Silurus. —
The only organ that can be regarded as con-
nected with the electrical function in this fish
is a thick layer of dense cellular tissue, which
completely surrounds the body immediately
beneath the integuments. So compact is it
that, at first sight, it might be mistaken for a
deposit of fatty matter. But, under the mi-
croscope, it appears to be composed of ten-
dinous fibres, closely interwoven, the meshes
of which are filled with a gelatinous substance.
This organ is divided by a strong aponeurotic
membrane into t\vo circular layers, one outer,
lying immediately beneath the corion, the other
internal, placed above the muscles. Both or-
gans are isolated from the surrounding parts
by a dense fascia, excepting where the nerves
and bloodvessels enter. The cells or meshes
in the outer organ, formed by its reticulated
fibres, are rhombic in shape, and very minute,
so as to require a lens to see them well. The
component tissue of the inner organ is some-
what flaky, and also cellular.

The nerves of the outer organ are branches
of the fifth pair, which runs beneath the lateral
line and above the aponeurotic covering of the
organ. This aponeurosis is pierced by many
holes for the transmission of the nerves, which
are lost within the cellular tissue of the organ.
The intercostals supply the inner organ : their
electrical branches are numerous and remarka-
bly fine.f

The organs of the other known electrical
fishes have not yet come under the notice of
any anatomist.

In taking a general view of these interesting
organs, we are struck \vith the existence of a
certain degree of analogy amongst them, and
yet we fail to discover such resemblances as
might be expected, and such as exist between
the structures of other organs performing the
same functions in different animals. Here we
have tendinous membranes variously arranged,
yet all so as to form a series of separate cells
filled with a gelatinous matter. But how great
is the difference between the large columnar
cell in the torpedo full of delicate partitions,
and the minute rhombic cells of the Silurus !
All, however, are equally supplied with nerves
of very great size, larger than any others in the
same animals; and, indeed, we may venture
to say, larger than any nerve in any other ani-
mal of like bulk.

The organs vary in different fishes ; first, in
situation relatively to other organs. They
bound the sides of the head in the torpedo ;
run along the tail of the Gymnotus, and sur-
round the body of the Silurus ; secondly, in
having different sources of nervous energy ;
and, thirdly, in the form of the cells. No
other fishes have aponeuroses so extensive, or
such an accumulation of gelatine and albumen
in any cellular organ. Broussonet remarked
that " all the electrical fishes at present known
to us, although all belonging to different classes,
have yet certain characters in common. All,
for instance, have the skin smooth, without
scales, thick, and pierced with small holes,
most numerous about the head, and which
pour out a peculiar fluid. Their fins are
formed of soft and flexible rays, united by
means of dense membranes. Neither the
Gymnotus nor torpedo has any dorsal fin ;
the Silurus has only a small one, without rays,
situated near the tail. All have small eyes."*

X. Analogies of animal electricity. — Setting
aside the vague hypotheses of the older philo-
sophers, (some of whom attributed the phe-
nomena produced by the peculiar power of
electrical fishes entirely to the mechanical effect
of certain rapid motions of their surface, and
others to the influence of currents of minute
corpuscules flowing from the body of the fish
in the act of discharging,) we can have no dif-
ficulty in referring this very remarkable series
of phenomena to the agency of some power
very analogous to common or voltaic elec-
tricity, which seems to stand in the same rela-
tion to these as they do to electricity derived
from other sources.f

It was by Muschenbroek that the effects
of the torpedo's discharge were first referred
to electricity. He was led to imagine that
the agent producing the shock was truly
electrical from the similarity of its effects
to those of the discharge of the Leydenjar.
Succeeding observations, however, as we
have seen, have shewn that certain differences
exist between the phenomena produced by
Animal Electricity and those observed in con-
nexion with the discharge of the Leyden jar :
the chief of these are — its passage through air
only to a very small distance; its producing
only very slight igniting effects even when con-
siderably accumulated; and its manifesting
but feebly the phenomena of attraction and
repulsion. Further, it affects the multiplier
more strongly than common electricity does
under ordinary circumstances, and its chemical
effects are more distinct. From voltaic elec-
tricity it is distinguished by the comparative
feebleness of its power of decomposing water;
by the greater sharpness of the shock caused
by the discharge, and by the weakness of its
magnetizing power.

Only four of the eight experimental effects
enumerated by Dr. Faraday \ as characteristic

* Abhandl. der Acad. v. Berlin, 1820-21. 229,
and Blainville, Princ. d'Anat. Comp. i. 232.

t Rudolphi, (Abhandl. der Acad. v. Berlin.
1824.) 140.

* Mem. de 1'Acad. de Paris, 1782. 693.
f It is interesting to know that the Arabic name
of the torpedo (Rausch) means also lightning,
$ Philo?. Trans. 1833.

94

ANIMAL ELECTRICITY.

of common and voltaic electricity are pro-
duced by animal electricity; which appears
to be sufficient to prove that the latter is as
much a peculiar power distinct from these as
are the agents called magneto-electricity and
thermo-electricity. Perhaps, however, what
we at present regard as so many powers dif-
fering from one another in their natures, may
be merely modifications of the same power,
varied in its sensible properties by changes in
the circumstances under which they are mani-
fested. This latter view is that taken by Dr.
Wilson Philip, who holds that Animal Elec-
tricity is just common electricity modified in
its properties by those of life, under the in-
fluence of which it operates in the living
animal.

Sir Humphry Davy thought he saw a
stronger analogy between common and animal
electricity, than between voltaic and animal
electricity, but concluded that the latter would
be found by more extended researches than
he was able to make to be " of a distinctive
and peculiar kind."* Cavendish, on the other
hand, believed that there is a complete identity
between common electricity and that of fishes.
And this he laboured to prove by imitating
several of the peculiarities of the discharge of
the torpedo by a particular arrangement of
small Leyden jars, forming a battery, from
which the electricity was discharged in large
quantity but of low intensity .f Others, again,
have attempted to trace a certain resemblance
between the structure of the electrical organs
of the torpedo and the formation of the voltaic
pile, " inasmuch as they are formed of alter-
nate layers of moistened conductors of dif-
ferent natures, to wit, of membranous parti-
tions, and of gelatinous and albuminous fluid."
(Tiedemann.) They suppose that the nerves,
being spread over one side of the transverse
partitions of the cells, produce opposite states
of electrical tension on the two sides of the
partition. In the present imperfect state of
electrical science, all such hypotheses are un-
satisfactory.

The only conclusions which, in our opinion,
can be legitimately drawn from the accumu-
lated facts on the subject are — that the shock
given by electrical fishes is caused by an agent
closely allied in its nature to common elec-
tricity and other like powers ;\ and that the
developement and discharge of this agent are
strictly dependent on the integrity of the ner-
vous communication between certain peculiar
organs and the great nervous centres.

It is evident that the nervous system plays
a very important part in the electrical function.
But whether its influence merely stimulates
the electrical organs to do what their organic

* Philos. Trans. 1829. 16.

t Philos. Trans. 1776. 196.

J The latest experiments on the subject, with
•which we are acquainted, are those of Messrs.
Becquerel and Breschet, reported to the Academy
of Sciences in October, 1835, (Ann, des Sciences
Nat. n. s. iv. 253,) which seem to have been per-
formed with great care. The experimenters com-
pletely satisfied themselves that the shock of the
torpedo is the result of an electrical discharge.

structure renders them capable of doing, or
really supplies them with a stream of the im-
ponderable agent which they accumulate, and
then, under voluntary impulses, discharge, is
still a point for further investigation. In the
structure of the electrical organs, we do not
see any arrangement such as researches in elec-
tricity artificially developed lead us to believe
fitted either to produce or to accumulate elec-
tricity. But this is in itself no reason why
we should conclude that the organs have not
such powers. It seems more in accordance
with what we know of the actions of other
parts of the animal frame, to believe that they
do possess such powers. But — if the elec-
trical organs, by their organic structure, be
fitted to develope and to discharge electricity
under the nervous influence, just as a gland
secretes its peculiar fluid and its ducts eject it,
why (it may be asked) are the nerves going to
these organs of so very great a size compared
with the same parts in other organs of similar
bulk and very energetic action ? Is their sub-
jection to the will of the animal sufficient to
account for the difference ? or does it indicate,
as some physiologists maintain, that the ner-
vous influence does more in this case than
merely supply the vital stimulus such as is
received by all other organs in common ? In
other words — is the agent discharged by the
fish as electricity first developed in the ner-
vous centres, and only accumulated in the
electrical organs ; and is this agent identical
with common nervism ? To these questions
we cannot yet give a satisfactory reply. They
point the way to some very interesting and im-
portant fields of investigation, and cheer us
with the hope of considerably extending our
acquaintance with the physiology of the nerves,
on the supposition that the phenomena of ani-
mal electricity shall one day be proved to be
owing to an accumulation and discharge of the
very "same agent that causes contraction of
muscles, &c. Such a view appears to have
been taken of this subject by Sir H. Davy
when he remarked,* " there seems a gleam of
light worth pursuing in the peculiarities of
animal electricity, — its connexion with so large
a nervous system, — its dependence on the will
of the animal, — and the instantaneous nature
of its transfer, which may lead, when pursued by
adequate inquirers, to results very important for
physiology." Treviranus, in 1818, suggested the
likelihood of the power concerned in the ma-
nifestation of electrical phenomena by animals,
being one of those on which continuance of
life in general depends. " Perhaps," said he,f
" it is the same power which enables the tor-
pedo to give electric shocks that is the imme-
diate cause of the contraction of muscular
fibres." The same hypothesis is thus ex-
pressed by Carus.J " Numerous nerves are
distributed upon the cells of the electrical
organs, and as it is through the agency of

* Philos. Trans. 1828.
t Biologie. v. 141.

| Traite element, d'anat. oomp. 2d edit. i. 392.
(French translation by Jourdan.)

ANIMAL ELECTRICITY.

these nerves that the organs act, it is not im-
possible that the nervous influence itself is
accumulated in these cells as in condensers,
and that it is discharged at will, just as this
influence is accumulated in the muscular tissue
to produce contraction of its fibres." It was
reflection on the phenomena of animal elec-
tricity that led Dr. Wollaston to form the hy-
pothesis, which he supported with so much
ability, of secretion in general being depen-
dant on electricity, conveyed by the nerves,
and acting on the secerning organs.* Dr.
Wilson Philip, also, thinks that the circum-
stances under which electrical action is mani-
fested by fishes go to the support of his theory
of the nervous influence being identical with
common and voltaic electricity. Dr. Faraday
says that, from the time that it was shewn that
electricity could perform the functions of the
nervous influence, he has had no doubt of their
very close relation, and probably as effects of
one common cause. To the numerous list of
learned observers who have speculated on this
interesting subject, we have to add the re-
spected name of Sir John Herschel, who
imagines that the present state of electrical
science warrants the conjecture, that the brain
and spinal marrow form an electric organ,
which is spontaneously discharged along the
nerves, at brief intervals, " when the tension
of the electricity reaches a certain point."f
Meissner, again, supposes that the blood be-
comes charged with electricity in the lungs,
during the chemical process of respiration ;
that the electricity immediately traverses the
nerves of the lungs, and then the other parts
of the ganglionic system ; that hence the cen-
tral organs of the nervous system become
charged ; and that the brain, on and through
which the will acts, being charged, excites the
several organs to activity through the medium
of their respective nerves, along which electric
currents are passed.]; The facts, (in addition
to those which have chiefly engaged our atten-
tion in this article,) upon which such theories
are built are, — (1) that the muscles of an
animal recently dead contract when common
electricity passes through them, just as they do
when they are subject to the animal's will;
(2) that voltaic electricity acts upon secreting
organs, so as to enable them in some degree to
carry on their functions after their proper nerves
have been cut; and (3) that the same agent
appears to influence powerfully the capillary
circulation. But, although these facts, taken
along with what we know of the phenomena
of the electricity of fishes, certainly do appear
to favour the views to which we have just

* Phil. Mag. xxxiii. 488.

t Discourse on the Study of Nat. Phil. 343.

t Syst. der Heilkunde. Wien. 1832. If hypo-
theses such as these should hereafter be proved to
express the true state of the case, the electrical
fishes will become objects of great interest to the
physiologist, as presenting him with opportunities,
such as no other animals afford, of studying in
accumulation the properties of that wonderful agent,
•which is the moving power of the animal organiza-
tion, and a very important link in the chain of
causes and effects by which life is manifested.

alluded, there are yet other facts which are so
hostile to them as to make it probable that
they do not express the truth. For instance,
the most carefully conducted experiments have
failed to demonstrate the existence of electric
currents through muscles during their contrac-
tion; which, from all that is known of the
phenomena exhibited by electricity in other
circumstances, it may be presumed would not
have been the case had it been the immediate
stimulant of muscular contraction. M. Per-
son has applied the poles of a galvanometer to
the spinal marrow without obtaining any indi-
cations of the existence of electrical currents
through its substance. The subjects of Per-
son's experiments were cats, dogs, rabbits,
eels, and frogs. The spinal canal having been
opened, the piles of the galvanometer were
placed in communication with the anterior and
posterior columns of the cord. This was done
at different parts, after the roots of the nerves
had been cut. Small plates of platina, with
which the wires of the instrument were armed,
were thrust into the cerebellum and into several
of the largest nerves. These experiments were
repeated after the animals had been placed
under the influence of strychnia. But there
was no certain indication of electricity ob-
tained, although the most delicate instruments
were used.* Person's experiments have been
repeated by Muller with the same results.
Messrs. Prevost and Dumas, however, state
that, having armed the branches of their gal-
vanometer with two wires of platina, exactly
alike, and having plunged one of them into
the muscles of a frog's leg, while, with the
other, heated to redness, they touched its
nerves, they saw considerable deviations of the
needle of the instrument follow the contrac-
tions of the muscles.f But seeing that the
electricity made manifest in this experiment
may have been developed rather by the con-
tact of the hot wire and the nerves than by the
nervous actions, we cannot admit that it is
sufficient to prove the existence of electrical
currents in muscles during their contraction.
Dr. Faraday, also, has lately experimented on
living muscles with the very delicate galvano-
meter invented by himself, but has entirely-
failed to obtain indications of moving electri-
city. Negative results such as these, obtained
by so many practised observers, are sufficient
to induce us to withhold our assent from those
theories which make nervism identical with
electricity, until the whole subject shall have
been more fully investigated.

As in some degree illustrative of the pheno-
mena of animal electricity, properly so called,
we must here take notice of the manifestation
of common electricity in animal substances and
in living animals.

The mere contact of heterogeneous bodies is

* Journal de Physiol. x. 217. Some years ago
M. Pouillet announced that he had witnessed
electrical phenomena during the operation of the
acupuncture of muscles ; but he has since con-
fessed that he was deceived.

t Edwards, De 1'influence des agens physiques
sur la Vie, in Appendix,

96

ANIMAL ELECTRICITY.

sufficient for the development of electricity; and
animal tissues of dissimilar natures, both living
and dead, obey the same law as other sub-
stances in this respect. For instance, a kind of
voltaic pile has been formed by building up layers
of muscle and nerve placed one above the other
alternately ; (Buntzen :) also by placing one upon
another alternate layers of muscular fibre and
brain, separated by a porous substance, soaked
in salt-water. (Lagrave.) Another such has
been made with plates of one kind of metal,
fresh muscle, and salt-water, or blood, which
acted on the galvanometer. When the con-
ductors of a galvanometer (Schweigger's) are
armed with plates of platina, on one of
which a piece of muscle of a few ounces in
weight is placed, and the conductors are then
plunged in blood or in a weak solution of salt,
a deviation of the magnetic needle of the in-
strument is perceptible. (Prevost and Dumas.)
The same happens when to one conductor is
applied a plate of platina moistened with mu-
riate of antimony or nitric acid, to the other a
piece of nerve, muscle, or brain, and both are
brought into contact. (Majendie.) Dry piles
of considerable electrical power may be formed
of organic materials alone, without the interven-
tion of metals. If concentrated extracts of
organic bodies (animal or vegetable) be spread
upon thin paper, and piles be built up of discs
cut from this paper, so that two dissimilar layers
be separated by two thicknesses of the paper,
so much electricity is developed that the elec-
trometer is affected. (Kcemtz.) When two
persons, both insulated, join hands, electricity
is developed sufficiently to affect Coulomb's
electroscope. And, if the contraction of mus-
cles, the nervous connexion of which with the
living body has been destroyed, be considered
as a proof that thpy are subject to the influence
of electricity, there are numerous experiments
on record tending to prove that electricity is
evolved by the mere contact of two dissimilar
animal substances. Galvani, Volta, Humboldt,
Aldini, Kellie, and Miiller, have all found that
when the muscles and the great nerves of a
frog's limb are touched synchronously with a
piece of the muscle of a warm-blooded animal,
weak contractions of the frog's muscles ensue ;
and that, when the crural muscles are cut and
folded back so as to touch the lumbar nerves,
muscular contractions are perceived in the lower
part of the limb. Aldini excited most powerful
contractions by bringing the nerves of a warm-
blooded animal into contact with the muscles
of a cold-blooded animal, and vice versa. And
Miiller has further found that contractions are
excited by touching the moistened skin of the
leg with the nerves of the thigh dissected out
and turned down upon them ; the nerves being
held by means of an insulating rod.*

Tiedemann thus states the general results of
experiments such as these. " 1 . The nerves
of the muscles in which it is proposed to excite
convulsions must make part of the chain.
2. The nerve or portion of nerve which is to

make part of the chain must be isolated as
completely as may be, and no other conductor
must produce derivation in this portion of the
chain, so as to oblige the electric current, when
developed in the chain, to take a course through
the nerves. 3. Cceteris paribus, the convulsions
are so much stronger, and are manifested over a
greater extent, as the nervous portion, acting as
a conductor, enters into the chain. 4. The
convulsions are so much more powerful, and
last the longer, as the chain is quickly formed,
and the surface with which the parts consti-
tuting it are in contact is extensive."* And
lastly, we now know that even the evaporation
of fluids, and changes in the molecular consti-
tution of both solids and fluids are always
accompanied by electrical excitation.

Applying these facts to our knowledge of
the various processes of the animal ceconomy,
we cannot but conclude that, in the course of
the many interchanges that are constantly taking
place amongst the component particles of all
living organs, electricity (perhaps modified by
the organic forces) must be developed alto-
gether independently of nervous influence. It
is certain, however, that electricity flowing from
this source is very feebly manifested ; at least it
affects our best electrometers in a very incon-
siderable degree. Saussure frequently ex-
amined the electricity of his own body by
means of Volta's electrometer, used along with
a condenser, but always failed to perceive any
indications of free electricity while he was
entirely naked. It was also imperceptible
while he perspired freely, and when his clothing
was cold. Under other circumstances, he found
the electricity of his body sometimes positive,
and at other times negative ; but he could not
determine the causes of these variations. Simi-
lar observations were made by Hemmer of
Mannheim in 1786, both on the electricity of
his own body, and on that of many other indi-
viduals placed in various circumstances. He
obtained the following results. 1. Electricity
is developed in all men, but varies in intensity
and in nature in different individuals. 2. The
character and intensity of the electricity fre-
quently varies in the same person. In 2422
experiments, it was 1252 times positive, 771
negative, and 399 times imperceptible. 3. When
the body is at rest and warm, its electricity is
always positive. 4. When the surface is much
cooled, the electricity becomes negative. 5. It
is also negative when the muscular vigour is
diminished. More recently this subject has
been investigated by Messrs. Pfaff and Ahrens.f
They used a gold-leaf electrometer; and the
subjects of their observations were insulated.
The collecting plate screwed on the electrometer
was touched by the person experimented upon.
The upper plate of the same was placed in
communication with the ground by means of
conductors. The results which they thus pro-
cured were as follows: — 1. The electricity of
healthy men is generally positive. 2. Irritable
men of sanguine temperament have more free

* Handbuch der Physiol. tics Mcnschen. Berlin,
1833.

* Physiol. transl. by Drs. Gully and Lane, 276.
t Mcckel's Archiv. iii. 161.

ANIMAL ELECTRICITY.

97

electricity than those of a phlegmatic tempera-
ment. 3. An increased accumulation of elec-
tricity takes place in the evening. 4. Spirituous
drinks augment its intensity. 5. The elec-
tricity of women is more frequently ne<jative
than that of men. 6. In winter, while the body
is very cold, no electricity is manifested, but it
gradually reappears as the body is warmed.
7. The whole body naked, as well as every part
of it, shews the same phenomena. 8. During
the existence of rheumatism, the electricity is
greatly diminished in intensity, but as the dis-
ease declines it again increases. Gardini found
that the electricity of women during menstrua-
tion and pregnancy is negative.

Some individuals exhibit electrical pheno-
mena much more readily than others. Some
persons, for instance, hardly ever pull off articles
of dress worn next the skin without sparks and
a crackling noise being produced. It is related
of a certain monk that sparks were always
emitted from his hair when it was stroked back-
wards; and of an Italian lady that her skin,
when rubbed with a linen cloth, gave out sparks,
attended with a crackling noise. The same
phenomenon, as exhibited by the cat, and by
other animals covered with a soft fur, is daily
observed. But it has been stated that the cat's
electricity may be accumulated in its own body
and given off suddenly, so as to produce a
shock. Homer says,* " If one take a cat in his
lap, in dry weather, and apply the left hand
to its breast, while with the right he strokes
its back, at first he obtains only a few sparks
from the hair; but, after continuing to stroke
for some time, he receives a sharp shock, which
is often felt above the wrists of both arms. At
the same moment, the animal runs off with
expressions of terror, and will seldom submit
itself to a second experiment." In repeating
this experiment, we have obtained the like
result.

We are not aware of any other observer having
met with any thing resembling an accumulation
of electricity in quadrupeds, excepting Cotugno,
who asserted that, in dissecting a living mouse,
he felt an electric shock when its tail touched
his finger.-f

XI. Uses of animal electricity. — The pur-
pose which the electrical function is fitted
to serve in the animal economy is proba-
bly not single. It is very evident that the
discharge from the organs frequently strikes
terror into the enemies of their possessors, and
thus it may be regarded as a means of defence ;
while, in certain circumstances, it may be useful
in enabling the fish more easily to secure its
prey. But this, probably, is not all. It is
very likely, as Dr. Roget has suggested,} that
the electrical organs communicate to the fish
perceptions of electrical states and changes in
surrounding bodies, (very different from any
that we can feel,) in the same way as other
organs of sense convey perceptions with regard

* Gilbert's Ann. der Phys. B. xvii.
t Humboldt. Ueber die gereizte Muskel-und-
Nervenfaser. Berlin, 1793. i. 30.
$ Bridgewater Treatise, i, 31.
VOL. II.

to light and sound. Such perceptions we can
conceive to be very useful and pleasurable to
animals living in the dark abysses of the waters.

Some of Dr. John Davy's observations make
it very doubtful whether the electrical function
is ever subservient to that of prehension of food.
He kept young torpedos for a period of five
months or more, in large jars of salt water,
during which time they ate nothing, although
very small fishes, both dead and alive, were put
into the water. Yet they grew, and their elec-
trical energies and general activity increased.*
The small fishes seemed to have no dread of the
torpedos. On one occasion, however, when a
lively torpedo was placed in a small vessel
along with a smelt, and excited to discharge,
the smelt was evidently alarmed, and once or
twice, when exposed to the shock, leaped nearly
out of the vessel, but it was not injured by the
electricity. It has also been frequently ob-
served of the gymnotus that it eats very few of
the fishes that it kills by its discharge.

The electrical power of the young fish is
proportionally very much greater than that of
the old, and can be exerted without exhaus-
tion and loss of life much more frequently.
After a few shocks, most of the old fish which
Dr. Davy has endeavoured to keep alive have
become languid, and died in a few hours,
whilst young ones, from three to six inches
long, remained active during ten or fifteen days,
and sometimes lived as many weeks. Hence
Dr. Davy concludes that the chief use of the
electrical function is to guard the fish from its
enemies, rather than to enable it to destroy its
prey, and so provide itself with food. He fur-
ther conjectures that, besides its defensive use,
the electrical function may serve also to assist
in respiration by effecting the decomposition of
the surrounding water, and so supplying the
gills with air when the fish is lying covered
with mud or sand, in which it is easy to con-
ceive that pure air may be deficient. And Dr.
Davy has often imagined that he saw something
of this kind going on. After repeated dis-
charges, he has observed, all around the margin
of the pectoral fins, an appearance as if very
minute bubbles of air were generated in it and
confined. That this may be one purpose
which the electrical function is designed to
serve, is rendered still more probable by the
circumstance, that the gills (in the torpedo at
least) are largely supplied with twigs of the
electrical nerves. In fishes in which he had
cut the electrical nerves, Dr. Davy found the
secretion of the cutaneous mucus considerably
diminished or altogether arrested ; and hence
he supposes that the electricity assists in the
production of this fluid.

Lastly, it has been conjectured that the elec-
trical function is subservient to that of digestion.
This idea was started by Mr. J. Couch some
years ago.f He says, " Without denying that
the torpedo may devour that which it disables
by the shock, I conceive that the principal use
of this power has a reference to the functions of

* Phil. Trans. 1835.
t Linn. Trans, xiv. 89.

98

NDOSMOSIS.

digestion. It is well known that an effect of
lightning or the electric shock is to deprive
animated bodies very suddenly of their irrita-
bility ; and that thereby they are rendered more
readily disposed to pass into a state of disso-
lution than they would otherwise be ; in which
condition the digestive powers of the stomach
can be much more speedily and effectually
exerted on them. If any creature may seem
to require such a preparation of the food more
than another, it is the torpedo, the whole intes-
tinal canal of which is not more than half as
long as the stomach."

These views receive some support from the
fact that the nerves of the stomach are derived
from those supplying the electrical organs ; and
perhaps also from the fact, reported by Dr.
Davy regarding a torpedo, in which, after it had
been frequently excited to give shocks, diges-
tion seemed to be completely arrested.

The only conclusion to which, in the present
state of our knowledge, we can come on this
point is, that although the electrical organs form
a very efficient means of defence from their
enemies for the fishes which possess them, this
is not the only purpose they are intended to
serve ; what, however, their other uses are is at
present only matter of conjecture.

There remains yet unentered upon a large
field of enquiry connected with the physiology
of those wonderful organs, which, we doubt
not, will yield to future ages very striking
examples of that nice and close adaptation of
means to ends which so clearly proves to us the
existence and continued exercise of Wisdom
Supreme, " upholding all things by the word of
his power," making the smallest of his works
" very good," and " to be thought upon."

BIBLIOGRAPHY. — Volta, Memorie sull' elettri-
cita animali, 1782. Galvani, Dell' uso e delP at-
tivita dell' arco conduttore nelle contrazioni del
moscoli. Bologna, 1794. Ejus. Memorie sulF
elettricita animale, Bologn. 1797. Fowler, Expe-
riments and Observations relative to the influence
called animal electricity. Lond. 1793. Aldini,
Essai Thcorique et experimental sur le Galvanisme,
et in Bulletin des sciences, an xi. No. 68. Pfaff*
Ueber thierische Elettricitat und Reizburkeit.
Leipzig, 1795. Humboldt, Versuche liber die ge-
reizte Muskel und Nervenfaser. Berlin, 1797.
Treviranus, Biologie. Tiedemann, Physiologic.
Mutter, Physiologic. Carus, Anat. Comp. French
ed. t. i. Lorenzini, Osservazioni interne alle tor-
pedini, Flor. 1678. Walsh, Phil. Trans. 1774.
Prmgle on the Torpedo, Lond. 1783. Ingenhousz,
Phil. Trans. 1775. Hunter, Phil. Trans, t. Jxiii.
et Ixv. Geoffroy Saint Hilaire, Ann. du Mus. t. i.
Humboldt, Recueil d'observ. de zoologie et d'anat.
romp. Knox, Edin. Journal of Science, 1824.
Todd, Phil. Trans. 1816. Davy, Phil. Trans. 1834.
Majendie and Desmoulins, Anat. des Systemes Nerv.
t. ii. Rtidolphi, Abhandl. der A cad. der Wissen-
Schaft in Berlin, 1820. Becquerel, Tiaite d'Elec-
Incite et Galvanism, t. iv. Par. 1836.

(John Coldstream.)

ENCEPHALON. In order to lay before
the reader a connected view of the Anatomy of
the Encephalon in conjunction with that of the
Medulla Spinalis, the Anatomy of both these
organs will be given under the article " NER-
VOUS CENTRES."

ENDOSMOSIS, (ivbov, intus, uffpos, im-
pulsus). — Accident having made me acquainted
with the fact that a small animal bladder, con-
taining an organic fluid, became considerably
distended by remaining for some time plunged
in water, and that the water even expelled the
thicker fluid contained within the bladder, when
there was a hole by which it could escape, I be-
thought me of the probable cause of this pheno-
menon, and soon came to the conclusion that it
depended on the difference of density between
the included or interior fluid, and the water or
exterior fluid. I found that the coeca of fowls
filled with milk, thin syrup, &c. and secured with
a ligature, became turgid and even excessively
distended when treated in the same way. I now
discovered that the fluids contained in the creca
permeated their coats, and were diffused in the
surrounding water. I saw, further, that two
opposite currents were established through the
parietes of the coeca; the first and stronger
formed by the exterior water flowing towards
the fluid contained in the cceca; the second
and weaker, by the thick included fluid flow-
ing towards the water. To the first of these
currents I gave the name of Endosmosis, and to
the second that of Exosmosis. These titles, I
must allow, are objectionable, and perhaps
badly chosen. The first conveys the idea of an
entrance and the second of an exit. Now, the
phenomenon, regarded in its proper point of
view, consists in a double permeation of fluids,
abstracted from any idea of entrance 'or exit.
Besides, the current of endosmosis, which,
etymologically speaking, expresses an in-going
current, may nevertheless be, experimentally
speaking, an out-going current ; this, for exam-
ple, happens when a hollow membranous organ,
containing water, comes to be placed in contact
exteriorly with a fluid more dense than water.
There is then a current of endosmosis which
goes out of the bladder, and a current of exos-
mosis which enters it. Thus facts are found in
contradiction to the terms, and these I should
not have hesitated to change, if their general
adoption did not render this change very diffi-
cult, and subject to great inconvenience. I have,
therefore, resolved to retain them, wishing it to
be understood by naturalists that no attention
is here paid to their etymological signification.

To estimate the amount of endosmosis I
contrived an apparatus to which I gave the
name of endosmometer ; it consists of a small
bottle, the bottom of which is taken out, and
replaced by a piece of bladder. Into this bottle
I poursome dense fluid, and close the neck with
a cork, through which a glass tube, fixed upon
a graduated scale, is passed. I then plunge
the bottle, which I entitle the reservoir of the
endosmometer y into pure water, which, by en-
dosmosis, penetrates the bottle in various quan-
tities through the membrane closing its bottom.
The dense fluid in the bottle, increased in quan-
tity by this addition, rises in the tube fitted to
its neck, and the velocity of its ascent becomes
the measure of the velocity of the endosmosis.

To measure the strength of endosmosis, I
have made use of an endosmometer in which
the tube was twice bent upon itself, the as-

ENDOSMOSIS.

99

cending branch containing a column of mer-
cury, which was raised by the interior fluid
of the endosmometer in proportion as the en-
dosmosis increased the volume of this fluid.*
By means of these two instruments I have
found that the velocity and strength of endos-
mosis follow exactly the same law. Both are
in relation to the quantities which express, in
two comparative experiments, the excess of
density of two dense fluids contained in the
endosmometerj above the density of water,
which in these two experiments is exterior to
the instrument. Thus, for example, in putting
successively into the same endosmometer, syrup
of which the density is 1.1, and syrup of which
the density is 1.2, and in plunging in both
cases the reservoir of the endosmometer into
pure water, you obtain in the first case an en-
dosmosis, of which the strength and velocity
are represented by 1 , and in the second case an
endosmosis, of which the strength and velocity
are represented by 2 ; that is to say, by the
numbers relative to the fractionals 0.1 and 0.2,
which express the excesses of density of the
two solutions of sugar above the density of
water, which is 1 . I have ascertained by ex-
periment that the strength of endosmosis is
such that, with syrup of which the density is
1.11, and an endosmometer, the opening of
which is closed by three pieces of bladder, one
over the other, you obtain an endosmosis which
raises the mercury to 1 metre 238 millimetres,
or 4.5 inches 9 lines, which is equivalent to an
elevation of water of 16 metres 77 centimetres,
or 51 feet 8 inches. It follows from this, that
in employing syrup, of which the density was
1.33, (its ordinary density,) you would obtain
an endosmosis, the strength of which would be
capable of raising water more than 150 feet.

Fluids of a different nature have, with refer-
ence to endosmosis, properties which are in no
way in proportion to their respective densities.
Thus sugar- water and gum- water of the same
density, being put successively into the same
endosmometer, which is plunged into pure
water, the former produces the endosmosis
with a velocity as 17, and the latter with a
velocity as 8 only. I have seen, in the same
manner, a solution of hydrochlorate of soda
and a solution of sulphate of soda of the same
density, put successively in the same endosmo-
meter surrounded with pure water ; the velo-
city of the endosmosis produced by the solu-
tion of sulphate of soda is exactly double that
of the endosmosis produced by the solution of
hydrochlorate of soda. These results are inva-
riable, and I am persuaded that if 1 have ever
obtained a different result, the experiment has
been defective.

I have made several experiments since with
gelatinous and albuminous waters placed suc-
cessively in the same endosmometer, surround-
ed with pure water, which produced endos-
mosis severally in the proportion of 1 to 4 ;
so that the albumen had four times more power
of endosmosis than the gelatine. I have seen

* See my work entitled, Nouvelles Recherches sur
I'endosmose et 1'exosmose, &c. 8vo. Paris, 1828.

by another experiment that the power of eii-
dosmosis of syrup is to the power of endos-
mosis of albuminous water of the same den-
sity, as 11 is to 12.

All alkalies and soluble salts produce en-
dosmosis; so do all acids, but each with spe-
cial phenomena, which will be noticed by and
by. These chemical agents in general occasion
an endosmosis of short duration only, when the
endosmometer is closed with a portion of an
animal membrane. Organic fluids alone, which
are not very sensibly either acid or alkaline, or
salt, produce lasting endosmosis, which, in-
deed, does not stop until the fluids are altered
by putrefaction, when they become charged
with sulphuretted hydrogen. I have shown that
when an endosmometer is closed with a thin
plate of baked clay instead of the animal mem-
brane, the endosmosis which a saline solution
produces, and which would have stopped in a
few hours with the animal membrane, continues
to go on indefinitely with the baked clay.

The property of destroying endosmosis may
be considered as belonging to all chemical re-
agents, but merely on account of their sus-
ceptibility to enter into combination with the
permeable partition of the endosmometer. Thus
all acids, alkalies, soluble salts, alcohol, &c.
being disposed to combine with the elements of
organic membranes, destroy endosmosis, al-
though they had induced it before their complete
combination with the elements of the membrane
had taken place ; and it is not until this combi-
nation is complete that endosmosis ceases. Or-
ganic fluids, which have no chemical action upon
the elements of the membrane of the endosmo-
meter, ought not, consequently, to tend to the
destruction of endosmosis, unless some change
should take place which should give them a
chemical action, such as they usually acquire
by decomposition, when they usually become
charged with sulphuretted hydrogen.

My earlier experiments tended to show that
carbonate of lime (chaux carbonatee) reduced
to thin laminae, and employed to close an en-
dosmometer, is totally without the power of
producing endosmosis ; my latter experiments
have somewhat modified this conclusion. After
having vainly employed laminae of carbonate
of lime of greater or less thickness, I finished
by making use of one of white marble, two
millimetres in thickness, but with no better
success. Without carrying my experiments
further, I concluded that porous carbonate of
lime was totally unapt to excite endosmosis.
This conclusion having, notwithstanding, left
some doubts in my mind, I again took the same
plate of marble with the intention of measuring
its permeability to water, compared with the
various degrees of thickness which I could give
it, and of renewing, at the same time, my at-
tempts to make it produce endosmosis. Having
closed an endosmometer with this plate of mar-
ble, I filled the reservoir and the tube of the
instrument with pure water, and suspended it
over a vessel filled with water, in which the plate
of marble only was immersed. If the marble
had been permeable to water, the fluid con-
tained in the endosmometcr would have flowed

H 2

100

ENDOSMOSIS.

through the capillary conduits of the plate, and
this flow would have become perceptible by
the sinking of the water in the tube, the inte-
rior of which was only two millimeters in dia-
meter.

The result of this experiment was that the
plate of marble, which was four centimeters in
diameter, did not lose by filtration, in one
day, more than the small quantity of water
capable, by its subtraction, of lowering its
level one millimeter and a half in the tube.
I next tried syrup in this endosmometer, the
reservoir being plunged into pure water ; but
no endosmosis was induced. I now reduced
the thickness of the plate of marble to one
millimeter and a half; in this state it lost by
filtration, in the course of a day, eleven mil-
limeters of water measured by the tube. The
.permeability of this plate was, as may be per-
ceived, very sensibly increased : still the en-
dosmometer which it closed when filled with
syrup showed no indications of endosmosis.
1 reduced the thickness of the plate of marble
to one millimeter. In this state it lost by fil-
tration, in the space of a day, twenty-one milli-
meters of water measured in the tube. I put
into the endosmometer, which this plate of
marble closed, the same syrup which had been
used in the preceding experiments, and the
density of which was 1.12, and I now ob-
tained an endosmosis which manifested itself
by an ascension of seven millimeters in four-
and-twenty hours. This last experiment proved
to me that carbonate of lime was not, as I had
hitherto found it, totally without the power to
.produce endosmosis. I wished to compare
-this plate of marble with a piece of bladder of
the same surface under the double point of
view, of their permeability, and their respec-
tive properties of producing endosmosis. Having
therefore taken off the plate of marble which
closed the endosmometer, I replaced it by a
piece of bladder whose permeability to water I
measured in the same manner as above. I found
this permeability very nearly equal to that of
the plate of marble of on-e millimeter in thick-
ness. I then put into this endosmometer
some syrup similar in density to that which I
had used in the same endosmometer closed
with the plate of marble. The endosmosis
which I obtained raised the syrup seventy-three
millimeters in three hours. Thus the permea-
bility to water being equal in the bladder and
in the plate of marble, the endosmosis pro-
duced by the first was to the endosmosis pro-
duced by the second as 584 is to 7, a most
extraordinary difference, and difficult to be
accounted for. These experiments prove that
carbonate of lime is but very little apt to pro-
duce endosmosis, in which it differs singularly
from baked clay, thin laminae of which are
almost as apt to produce endosmosis as organic
membranes. ,

The varieties of sulphate of lime which may
be employed in endosmometrical experiments
are riot sufficiently numerous or of sufficient
variety of permeability for it to be possible to
appreciate the properties of this substance in
relation to endosmosis. I found that the sul-

phate of lime used in the manufacture of
plaster in the environs of Paris, employed in
thin plates to close an endosmometer, did not
produce endosmosis. But this mineral is per-
haps too easily permeable. In fact it is found
impossible to obtain endosmosis when the in-
terior fluid of the endosmometer flows easily
by filtration, in virtue of its weight, through
porous plates. I should say as much of plates
of freestone (gres) which I have employed
without success in these experiments, but that
I recollect to have obtained the phenomenon
in a very slight degree with a plate of freestone
very close-grained and very little permeable to
fluids.

I have tried a variety of experiments shew-
ing that an increase of temperature increases
endosmosis. This result has been confirmed
by repeated experiments.

The quantjty of the same fluid introduced
by endosmosis, and with the same sort of per-
meable partition, is generally in proportion to
the extent of surface of this partition. The
following experiment demonstrated this fact.
I took two endosmometers, the membranes of
which, taken from the same bladder, were of
diameters in the relation of one to two ; I filled
the reservoirs of these two endosmometers with
syrup of equal density, and then plunged them
into pure water. I had taken care to weigh
them previously with great exactness. After
continuing the experiment for two hours, I
weighed the instruments afresh, and found in
the large endosmometer four times as great an
increase of weight as in the small one, which
proved that the first had introduced, by endos-
mosis, four times as much water as the second.
This relation was exactly that of the extent of
surface of their respective membranes, the
diameters of which were as one is to two, and
their surfaces consequently as one is to four.

I have thus enumerated the effects; let us
now endeavour to ascertain their causes.

The first idea which presented itself to my
mind to explain the phenomenon of endosmosis
was that it was owing to electricity. We know
that effects exactly similar to those of endos-
mosis are produced by means of the electricity
of the voltaic pile in the experiment of M.
Porret, inserted in the Annales de Chimie,
vol. xi. p. 137. This naturalist having divided
a vessel into two compartments by a septum of
bladder, filled one of the compartments with
water, and put only a small quantity in the
other. Having placed the positive pole of the
pile in communication with the compartment
full of water, and the negative pole with the
compartment containing little water, the fluid
was forced through the bladder from the full
compartment into the almost empty one, and
there rose to a higher level than that to which
it was reduced in the original full compart-
ment.

I varied this experiment by applying it to my
own apparatus. I put pure water into an
endosmometer, the membrane of which was
plunged into water. I made the interior water
of the endosmometer communicate with the
negative pole of the pile, and the exterior

ENDOSMOSIS.

water with the positive pole. I soon saw the
water rise in the tube of the instrument : en-
dosmosis had taken place. The similarity of
effects led me to admit that some particular
and unknown mode or form of electricity was
the cause of the endosmosis produced by the
heterogeneous nature of fluids. It was in
vain, however, that I tried to discover signs of
this electricity with the most delicate electro-
meters.

In reflecting afterwards upon what might be
the common cause of the phenomenon pre-
sented in Porret's experiment and that of or-
dinary endosmosis, I was inclined to think
that electricity might not be the immediate
cause of the effects exhibited, and that it only
acted in the case cited by producing heteroge-
neousness of quality in the two fluids subjected
to the positive and negative poles. Experience
seems to have confirmed my doubts on this
point. I took a small endosmometer of glass,
closed by a piece of bladder, and filled its re-
servoir with water coloured blue with the co-
louring matter of violets ; I plunged the reser-
voir of this endosmometer into the same co-
loured water contained in a small glass vessel ;
I put this latter fluid in communication with
the positive pole of the voltaic pile, and the
interior fluid of the endosmometer in commu-
nication with the negative pole. The exterior
blue fluid soon became red, and consequently
acid, and the interior blue fluid became green,
and consequently alkaline. These two fluids
having thus become heterogeneous, to this may
be ascribed the endosmosis which manifested
itself, and which increased the volume of the
interior fluid at the expense of the volume of
the exterior fluid. Thus electricity would not
be in this case the immediate cause of endos-
mosis, but the remote one ; it would only act
in producing the heterogeneous quality in the
two fluids, and it would be this quality which
would produce the passage of fluids as in the
experiments on endosmosis, the discovery of
which belongs to me.

But let us now inquire in what way hetero-
geneousness of quality in two fluids, separated
by a membranous partition, occasions the phe-
nomenon of endosmosis. Upon this point
opinions are greatly divided. M. Poisson and
Mr. Power have each, in his own way, given
an analytical explanation of the phenomenon,
and ascribed it to the action of the capillary
canals of the porous septum interposed be-
tween the two fluids. In this explanation the
phenomenon of the current of exosmosis is set
aside, or regarded as occurring merely acciden-
tally. Now this is entirely opposed to the fact,
— we have constantly evidence of the simulta-
neous existence of the two opposite and une-
qual currents of endosmosis and exosmosis.

Endosmosis by others has been held to be
simply the effect of the viscidity of one of the
fluids divided by a porous septum. This visci-
dity prevents the upper fluid from permeating
the interposed septum, whilst the inferior fluid,
little or not at all viscid, filters readily through
the septum and mingles with the upper fluid,

whose volume it continently increases. ThiV
opinion, published by a man of distinction, de-
serves to be seriously investigated.

When an equal weight of gum arabic and of
sugar is dissolved in two equal weights of water,
the viscidity of the different solutions is by no
means the same, the solution of the gum is ob-
viously more viscid than that of the sugar.
Now if these two solutions be divided by a
piece of bladder, the current of endosmosis
will be found to flow from the solution of the
gum towards that of the sugar ; in other words,
from the more viscid to the less viscid fluid;
in this instance, consequently, we see the more-
viscid fluid permeating the membrane with
greater facility or in greater quantity than the
less viscid fluid. More than this, the same
phenomenon takes place if the quantity of the
gum be made double that of the sugar. 1 have,
for instance, tried a solution of two parts of
gum arabic in thirty-two parts of water, (den-
sity 1.023,) and a solution of one part of sugar
in the same quantity of the menstruum, (den-
sity 1.014,) divided by a piece of bladder, and
found that the endosmotic current was still
directed from the solution of the gum towards
that of the sugar. These facts suffice to prove
that the endosmotic current does not always
flow from the less towards the more viscid
fluid. It is not, therefore, the inequality of
vicosity in these two fluids which is, in this
instance, the cause of their unequal permeation
across the porous lamina which separates them.

In order to place these facts beyond a doubt,
the comparative viscidity of the gum-water and
the sugar-water which were made use of in the
experiments of which I have been speaking,
required to be accurately measured. Such a
comparative estimate of the viscidity of fluids
may be obtained by observing the time which
an equal quantity of each of them, at the same
temperature, takes to run through a glass capil-
lary tube. In this way I tried, 1st, pure water;
2d, a solution of one part of sugar in thirty-two
parts of water; 3d, a solution of one part of
gum-arabic in thirty-two parts of water; 4th, and
lastly, a solution of two parts of gum in thirty-
two of water. With a temperature of +7° cent.
I found that fifteen centilitres of pure water
passed through a capillary tube of glass in one
hundred and fifty-seven seconds; that fifteen
centilitres of the solution of one part of sugar
in thirty-two of water passed through the same
tube in one hundred and fifty-nine seconds and
a half; that fifteen centilitres of the solution of
one part of gum in thirty-two of water passed
through in two hundred and sixty-two seconds
and one-third ; and that the same quantity of
the solution of two parts of gum in thirty-two-
of water required three hundred and twenty-six
seconds to pass through.

From these experiments it appears that the
viscidity of the solution of sugar, in the propor-
tion of one to thirty-two of water, (density
1.014,) is very little above that of pure water;
that the viscidity of the solution of gum-arabic,
in the proportion of one to thirty-two of water,
is much greater than that of the sugared water

102

ENDOSMOSIS.

just mentioned;- and filially, that the viscidity
of the gum-water, containing two parts of gum
to thirty-two of water, (density 1.023,) is twice
as viscid as the solution of sugar employed.

It seems that nothing more is wanting to
these proofs of the fact that endosmosis does
not depend on the mere viscidity of fluids.
Nevertheless I shall cite another proof of this
truth. The very singular fact I am about to
mention will also prove that the septa employed
exert a special influence on the direction in
which endosmosis takes place.

It is well known that, in separating water
from alcohol by an organized animal or vege-
table membrane, the endosmotic current flows
from the water towards the alcohol. I employed
oil-silk (taffetas gomme) or silk covered with a
layer of caoutchouc, which may be regarded as
equivalent to a thin lamina of elastic gum, as
the medium of separation between these two
fluids. During the first thirty-six hours of the
experiment, I observed an extremely slow en-
dosmotic current from the alcohol towards the
water. After this period the endosmosis, with
the same direction, became very rapid. This
increase in the rapidity of the endosmosis I
considered due to some alteration in the caout-
chouc produced by the action of the alcohol,
and in consequence of which it became more
readily permeable. The endosmotic current,
however, let it be observed, is always from the
water towards the alcohol in this experiment,
instead of being from the alcohol towards the
water, as is constantly the case when the septum
between the spirit and the water is formed by
an organic, whether animal or vegetable, tissue.
We have thus a clear demonstration of the
great influence possessed by the septum upon
the direction of the current of endosmosis. We
have, also, in the instance just quoted, a proof
that the different degrees of viscidity of two
liquids plays no part in the production of this
phenomenon. I would remark that the endos-
motic current carrying the alcohol towards the
water athwart the septum of caoutchouc is ac-
companied by a counter-current, which carries
the water towards the alcohol through the same
septum. I assured myself that the alcohol had
received some addition of water; and yet it is
well known that caoutchouc is impermeable to
water ; which would seem to say that the latter
fluid could only have passed through the sep-
tum of caoutchouc by becoming mingled with
the alcohol occupying the molecular interstices
of that substance. Once within these intersti-
ces the alcohol attracts the water by the affinity
of mixture, (affinite, de mixtion) and enables
it to penetrate the substance of the caoutchouc,
which denies all access to water when it is
pure. It is therefore to the state of commixtion
within the capillary tubes of the septum that the
two opposed fluids proceed the one towards
the other with cross but unequal motions. The
means I took to ascertain the fact of water
having become mixed with the alcohol was
simple enough : I set fire to a quantity of the
fluid which had served for the experiment, and
found that, after all the spirit had burned out,

a considerable quantity of water remained,
whilst the alcohol, previously to being so em-
ployed, burned away entirely, leaving no water
behind it.

The theoretical views of Magnus in regard
to endosmosis have been adopted by Berzelius
in his Chemistry, and the idea upon which they
are based has been reproduced by M. Poisson.
To give a clear notion of this theory, let us sup-
pose that a measure of salt water is separated
from a measure of pure water by a permeable
septum, a piece of bladder for example ; the
current of endosmosis, in this instance, will be
from the pure water towards the salt, and for
the following reason : in the salt water there
are three attractions, namely, the attraction of
the molecules of the water for one another;
secondly, the attraction of the molecules of the
salt for one another; and thirdly, the reciprocal
attraction of the molecules of the water and of
the molecules of the salt. The pure water on
the opposite side of the septum again has no
more than a single form of attraction, to
wit, that of its particles for one another. The
salt water subjected to three attractions will be
moved, it may be imagined, with greater diffi-
culty than the pure water, the molecules of
which are obedient to but one attraction. Con-
sequently, in the reciprocal attraction of these
two fluids, the one, the molecules of which are
the least subjected to attraction among them-
selves, will make its way with greatest rapidity
athwart the capillary conduits of the dividing
membrane.

This theory has a seducing aspect, but we
shall find immediately that it is inapplicable to
certain endosmotic phenomena presented by
acids.

I have shown above that it is not always to-
wards the denser fluid that the endosmotic cur-
rent is turned. Thus alcohol and ether are
very much less dense than water, and yet it is
towards these fluids of inferior density that
water flows in endosmotic experiments. Alco-
hol and ether have this in common with dense
fluids generally, that they rise to a less height
in capillary tubes than water. From this ob-
servation I was led to imagine that the endos-
motic current was always from the fluid having
the greatest power of capillary ascension, to-
wards the fluid having the least of this capa-
city. It is true, indeed, as we have already
seen, that alcohol proceeds by endosmosis to-
wards water when the medium dividing them
is caoutchouc. This would seem to say that
alcohol would rise higher than water in capil-
lary tubes of caoutchouc; and it is certain that
caoutchouc has a greater attraction for alcohol
than for water, inasmuch as the surface of
India-rubber is much more readily wetted by
alcohol than by water, which only adheres to
it partially and imperfectly. This fact, there-
fore, would not be in contradiction to my
theory ; although I must confess that it is not
reconcilable with certain endosmotic pheno-
mena presented by the acids, as we shall imme-
diately have occasion to perceive. In spite of
this, however, I do not think I ought to pass

ENDOSMOSIS.

103

in silence all the proofs that seem to establish
this theory upon a basis of sufficient solidity;
for I cannot but perceive that it is applicable
to the most general phenomena of endosmosis,
phenomena, too, which the acids, like all other
fluid bodies, exhibit, although they also present
endosmotic phenomena in addition of a diffe-
rent nature, and which belong to them exclu-
sively.

Inequality of density being one cause of en-
dosmosis among fluids, it became a point with
me first to ascertain what differences in power
of capillary ascension resulted from determi-
nate differences of density among fluids ; and
next, to discover whether the difference in
power of capillary ascent of two fluids bore
any constant ratio to the difference of endos-
mosis as it is proclaimed by experiment.

The height to which different fluids rise in
capillary tubes depends on a variety of causes,
in appearance very different, but which must
have some fundamental analogy. Of all fluids
water is that which rises highest; and sub-
stances held dissolved in it which increase its
density, lessen its power of capillary ascent,
which is also diminished by increase of tempe-
rature : hot water ascends a less way in a capil-
lary tube than cold water. Combustible fluids,
such as alcohol and ether, are like dense fluids
in regard to power of capillary ascent ; so that
combustibility acts in the same manner as den-
sity in this respect. The matter of which ca-
pillary tubes are formed is also endowed with
the power of modifying the capillary ascent of
fluids. Thus water, at the same temperature,
will not rise to the same height in a series of
equal capillary tubes made of different mate-
rials. These multiplied elements, which enter
into the determination of the capillary ascend-
ing power of different fluids, render it an ex-
tremely complicated phenomenon. To simplify
the study of this phenomenon in the greatest
possible degree, let us confine ourselves to the
use of two fluids, namely, water and a solution
of the hydrochlorate of soda. It is easy to try
the latter fluid of different densities, and to
compare the power of capillary ascent pos-
sessed by each of these with that of pure water
at like temperatures. The same glass tube will
answer for these comparative experiments. Be-
fore detailing these experiments, however, I
have one important remark to make, which is
this; that the layer of fluid which moistens,
internally, the canal of a tube is one of the
elements of the capillary ascension which this
tube effects. Thus, water will rise to a de-
terminate height, in a tube interiorly moistened
with water ; but if the interior of the tube be
moistened by a saline solution, or by any other
watery fluid, or by alcohol, pure water will not
again rise so high in this tube as when it was
moistened by water only. It will be in vain
to attempt to cleanse the tube by passing water
repeatedly through it; water will never detach
the stratum of saline or other liquid which ad-
heres to it, and which diminishes its power of
producing capillary ascension. To detach this
stratum of fluid you must pass a filiform body
repeatedly through the tube full of water ; it is

only by the rubbing of this body that the stratum
can be detached. It must be evident after this
observation, that in making experiments on the
power of capillary ascension with various
fluids and with the same tube, it is necessary
to cleanse this tube with great care before each
experiment ; without this we should have de-
fective results. We must also take care not
to warm the tube by holding it between the
fingers, for if the temperature be increased it
will no longer exert so strong a capillary attrac-
tion. Let us now pass to the detail of these
experiments.

I prepared a solution of hydrochlorate of
soda, the density of which was 1.12, the den-
sity of the water being one. I took a part of
this solution and to it added an equal volume
of water, which gave it a density of 1.06. I
had thus two saline solutions, of which the
excess of density, above the density of water,
was 0.12 and 0.06. The excess was thus
in the relation of two to one. From my former
experiments, these two excesses ought to serve
as measures of the endosmosis produced by
each of these saline solutions, put successively
into the same endosmometer plunged in pure
water. In fact, having submitted both of the
saline solutions to experiment, I obtained from
the most dense solution an endosmosis exactly
double of that which was produced by the least
dense solution. I next inquired into the rela-
tion existing between the known density of these
two saline solutions and water, and the power of
capillary ascension possessed by the three fluids.
I took a glass tube, whose capillary action
raised water to the height of 12 lines at a
temperature of + 10 degrees R. (50 Fahrenh.)
I found that the same tube, at the same tem-
perature, raised to 6, lines the solution of
hydrochlorate of soda, the density of which
was 1.12, and that it raised to 9| lines the
solution of the same salt, the density of which
was 1.06.

1 . The capillary ascension of the water
being .... 12

The capillary ascension of the most
dense fluid being 6 {

The excess of the capillary ascension
of water is 5 $

2. The capillary ascension of water

being 12

The capillary ascension of the least
dense saline solution being 9|

The excess of the capillary ascension
of water is 2 1

Thus the two excesses of the capillary ascen-
sion of water above the capillary ascension of
each of these saline solutions are 55 and 2|, or
4f and 2f. numbers which are in the relation of
two to one, as are the two excesses 0.12 and
0.06 of the density of the two saline solutions
above the density of water. Here, then, are two
saline solutions which, put separately in relation
to pure water, produce endosmosis intherelation
of 2 to 1. Shall we refer this result to the

104

ENDOSMOSIS.

circumstance that the excesses of density of
each of these saline solutions over the density
of water are in the ratio of 2 to 1, or to this,
— that the excesses in the power of capillary
ascent of each of these saline solutions over the
power of capillary ascent of water are in the
ratio of 2 to 1 ? In other words, is it the re-
spective density of the two fluids which regu-
lates or determines their endosmosis, or is it
the respective powers of capillary ascension of
the fluids severally ?

The following experiment will solve this
question. We have seen above that a solution
of sulphate of soda and a solution of hydro-
chlorate of soda of equal densities being put
in relation to pure water, produce endosmoses
which are in the relation of two to one. Here
the difference of density does not interfere with
the regulation of the endosmosis ; we must then
see if it be regulated by the power of capillary
ascension. I prepared a solution of sulphate
of soda and one of hydrochlorate of soda, having
the same density 1.085, and tested their ca-
pillary ascension in the same tube in which we
nave seen pure water raised to a height of 12
lines at a temperature of + 10 degrees R.
I found that in the same tube and at the same
temperature the capillary ascension of the so-
lution of sulphate of soda was of 8 lines,
and that of the solution of hydrochlorate of
soda was of 1 0 lines. The excess of the capil-
lary ascension of water above that of the solu-
tion of sulphate of soda is consequently 4 ;
the excess of the capillary ascension of water
above the solution of hydrochlorate of soda is
2. These two excesses are in the relation of
two to one, a relation which also measures the
endosmosis produced with the concurrence of
water by each of these two solutions of equal
density. The result of this is that the capillary
ascension, or power of capillary ascent, of fluids
governs their endosmosis, and that their density
only intervenes in this case as the determining
cause of their capillary ascension. But how
does the capillary action operate here ? This ap-
pears to be difficult to determine. The capillary
action never carries fluids out of the canals in
which it takes place ; how then apply this action
to the phenomenon of double permeation, which
takes place in endosmosis and exosmosis ?
This double permeation, which carries two he-
terogeneous fluids towards each other, seems
as though it were the result of the reciprocal
attraction of the two fluids, of their tendency
to associate by admixture. In experiments of
endosmosis made with a dense fluid and water,
the tendency to mix is favoured by the respec-
tive positions of the two fluids; the dense
fluid is above and the water below. This dis-
position may possibly be one cause which fa-
vours the reciprocal mixture of the two fluids,
whose specific gravity would tend to place
them in an inverse situation to that given them
in the experiment. This does not take place
when experiments on endosmosis are made
with alcohol and water ; then the alcohol, spe-
cifically lighter than water, is situated above
this latter fluid, and, notwithstanding this, the
endosmosis is exceedingly energetic ; we must

then acknowledge that the specific gravity of
two fluids has not here the degree of influence
that might be supposed to belong to it at first
sight. We have consequently no means left to
explain the course of the two fluids towards each
other athwart the capillary canals of the parti-
tion which separates them, but their reciprocal
attraction or tendency to admixture. In ad-
mitting that such is the efficient cause of this
double permeation we must also necessarily
admit that this efficient cause is governed in
its operation by the capillary action of the par-
tition.

Here another question presents itself, — do
the two fluids accomplish their admixture
in the capillary canals themselves, or do they
cross the partition by different capillary canals,
so that neither fluid mixes with its opposite
fluid until the moment of its exit from the
capillary canals ? On the latter hypothesis it
were necessary to admit that the number and
diameter of the capillary canals followed sepa-
rately by each of the two fluids must be per-
fectly equal, for, without that, how would the
general result of this double permeation, a result
which is explained by the quantity of endosmo-
sis, be in exact relation with the capillary action
on the two fluids? Now it is repugnant to
reason to admit any such perfect equality among
all the capillary canals, or to suppose an equal
number especially fitted for the transmission of
each of the two fluids. It must then necessarily
be allowed that the transmission of the two op-
posite fluids takes place by the same capillary
canals, and that consequently this double
movement of transmission takes place by a
reciprocal penetration of the two fluids.

The preceding theory, with which I was at
one time inclined to rest satisfied, and which,
indeed, seemed to be based on a sufficiently
firm foundation, was however brought into jeo-
pardy by a discovery which I made subse-
quently, in regard to the phenomena of endos-
mosis exhibited by certain acids separated
from pure water by a layer of animal mem-
brane.

In the earliest experiments I made on the
endosmosis of the acids, I observed a number
of anomalous phenomena, for which I felt my-
self incompetent to assign any sufficient reason.
I had always placed the acids above the water,
from which they were separated by a layer of
animal membrane. Certain acids, such as the
hydrochloric, at very different degrees of den-
sity, and nitric acid only at pretty high degrees
of density, gave me an endosmosis, the current
of which was directed from the inferior water
towards the superior acid, so that the acid rose
gradually in the tube of the endosmometer.
On the other hand, I had always found the
sulphuric acid pretty largely diluted, and the
hydrosulphunc acid, under the same circum-
stances as the acids mentioned above, gradually
to sink in the tube of the endosmometer. I con-
cluded from this that these acids did notoccasion
any endosmosis, and that they passed mechani-
cally, and merely in virtue of their gravity,
athwart the animal membrane to mingle with
the water. I had also found that the sulphuric

ENDOSMOSIS.

105

and hydrosulphuric acids, added to gum-water,
deprived it of the faculty of producing endos-
mosis, and that this acidulated water fell in the
tube of the endosmometer, instead of rising, as
simple gum-water constantly does. The^e facts
induced me to say metaphorically that the sul-
phuric and hydrosulphuric acids were the ene-
mies of endosmosis.

More recent inquiries have enabled me to
see the above mentioned phenomena in ano-
ther light. It was the oxalic acid which led
me to the conclusions I shall now lay be-
fore the reader. Having poured a solution
of this acid into the endosmometer closed
with a piece of bladder, and placed the re-
servoir in water, I found the acid fluid sink
rapidly in the tube, and flow towards the
inferior water, making its way by filtration
through the animal membrane. I then reversed
the arrangement observed in this experi-
ment. I filled the endosmometer with water,
and plunged the reservoir into a solution of
oxalic acid. I was now surprised to find the
water making its way rapidly into the endos-
mometer, and the column rising in the tube, so
that, in opposition to all I had yet observed,
here was the current of endosmosis directed
from the acid towards the water. The follow-
ing are the particulars of this experiment.
Having poured some rain-water into the reser-
voir of the endosmometer, I plunged the reser-
voir, closed with a piece of bladder, into a so-
lution of oxalic acid of the density of 1.045,
(11.6 parts of crystallized acid in 100 of the
solution,) the temperature being + 23 cent.
The ascent of the water in the tube of the en-
dosmometer lasted for three days, becoming
gradually slower and slower. The ascent hav-
ing then become almost imperceptible, I emp-
tied the endosmometer, in the contents of
which I found water charged with oxalic acid.
The exterior fluid was reduced in density to
1.033, so that, whilst the lower acid had pene-
trated the upper water by endosmosis, the
water had penetrated the acid by exosmosis,
and thus diminished its density ; the permea-
tion of the water, however, had been less con-
siderable than that of the acid ; so that the
upper water, increased in volume, had risen in
the tube of the endosmometer. We have thus,
in the present instance, another obvious proof
of the existence of two opposite and unequal
currents. Having filled the reservoir of the en-
dosmometer anew with rain-water, I placed it in
the solution of oxalic acid already used, and of
the reduced density of 1.033. The ascent in
the tube which again occurred, having almost
ceased at the end of two days, I tested the
fluid in the endosmometer, and found it to con-
tain oxalic acid, and discovered the density of the
external fluid further reduced to 1.025. I re-
peated the same experiment a third time, filling
the reservoir of the endosmometer with rain-
water, and plunging it in the old acid solution.
Endosmosis went on as before, but with less
celerity. Having given up the experiment, after
the lapse of twenty-four hours I found the
density of the exterior fluid now reduced to
1.023, and the internal fluid to contain a por-

tion of oxalic acid as before. I reduced the
densiiy of the exterior acid solution to 1.01,
but the included water still gave evidence of a
pretty active endosmosis. I reduced the den-
sity of the acid to 1.005, (1.2 of acid to 100
of the solution,) and the endosmosis was still
very remarkable. In these experiments I found
that the endosmosis was by so much the more
rapid as the exterior acid solution was more
dense, so that the capacity of oxalic acid to
permeate an animal membrane would appear
to increase with the density of its solution in
water. In these experiments, too, we observe
a fluid, more dense than water, and having a
less power of capillary ascent than it, never-
theless forming the stronger current, or current
of endosmosis, whilst the water opposed to this
fluid forms the weaker current, or counter-cur-
rent of exosmosis. This is in opposition to all
I had observed before ; and the theory I had
raised on the different capacities of capillary
ascent possessed by two opposed fluids is con-
sequently shaken, or at all events proved to be
no longer generally applicable. What may be
the cause of this new phenomenon ? Do animal
membranes give passage more readily through
their meshes to solutions of oxalic acid than to
water ? This point I sought to determine by
the following experiments.

The filtration of a fluid, by virtue of its gra-
vity, through a porous lamina, the capillary
canals of which are very minute, is not readily
appreciable, unless the inferior or outer surface
of this porous plate is kept plunged in or
moistened by the same fluid. It is in this way
only that the filtration of fluids through animal
membranes, the texture of which is dense (a
piece of bladder for example,) becomes appre-
ciable. It is essential that the inferior aspect
of the membrane be bathed with the same fluid
as that which rests on its superior aspect, in
order that no foreign cause modify its nitration.
We know in fact that the heterogeneousness of
two fluids, by producing endosmosis, would
completely mask the effects of simple filtration.
W'ould I, then, try the filtration of water through
a membrane, I apply this membrane to an en-
dosmometer, which I fill with water to a certain
height in the tube of the instrument; I next
apply the lower surface of this membrane to
the surface of a body of water placed below it.
The water contained in the endosmometer filters
through the membrane and mingles with the
water in the vessel below ; the amount of this
filtration in a given time is indicated by the
fall of the column in the graduated tube of the
instrument. Would I essay comparatively the
filtration of any watery solution, I place this
solution in the same endosmometer, and taking
care to keep the exterior of the membranous
part of the instrument in contact with a solution
of the same nature, situated below it, I observe
the degree to which the depression of the co-
lumn in the tube takes place in a space of time
equal to that which was taken by the filtration
of the water. It is necessary to begin by
proving the filtration of water; after this the
filtration of the watery solution may be tried ;
but it is always to be borne in mind that the

106

ENDOSMOSIS.

membrane of the endosmometei: must have
been kept plunged in the watery solution about
to be experimented on for at least a quarter of
an hour, in order that it may become tho-
roughly impregnated with the solution, and to
secure that this should take the place of the
water which the membrane had formerly con-
tained in its pores. Without this measure of
precaution, the results of the second experi-
ment would be faulty. It is also indispensa-
ble that the circumstances under which the
two experiments are performed are in all re-
spects exactly alike. It was in this way that I
proceeded to ascertain comparatively the capa-
city of nitration of water to that of a watery
solution of oxalic acid through a piece of blad-
der. I found that the nitrating power of rain-
water, at the temperature of -4- 21 cent, being
denoted by 24, the nitrating power of a watery
solution of oxalic acid of no greater density
than 1.005, (1.2ofacidto lOOof solution,) was
denoted by 12. A solution of the same acid, of
thedensityof 1.01, beingtried, its filtrating power
was found to be represented by 9. By these ex-
periments it is therefore proved that water tra-
verses an animal membrane more readily than
a solution of oxalic acid. Why then does the
latter solution traverse an animal membrane
more readily and in greater quantity than water,
when it is water which is in contact with the
surface of the membrane opposite to that which
is in contact with the acid ? This is a question
which I find it impossible to answer in the
present state of our knowledge.

The discovery of this singular property of
the oxalic acid to cause the endosmotic current
to flow towards the water when separated from
the latter fluid by a lamina of animal mem-
brane, led me to imagine that all the acids
would be found to possess a similar property.
And this I ascertained, in the first instance, to
be the case in regard to the tartaric and citric
acids. Both of these acids are much more so-
luble in water than oxalic acid. The saturated
solution of oxalic acid at + 25 cent, has no
higher a density than 1.045 (11.6 acid to 100
of the solution.) But the solubility of the tar-
taric and citric acids is such that their watery
solutions may have a density of far greater
amount. I tried the endosmotic effects of the
tartaric and citric acids in watery solution of
various density, and I discovered, not without
surprise, that very dense solutions of them and
solutions of inferior density exhibited endos-
motic phenomena in inverse ratios. Thus,
when a solution of tartaric acid was of a den-
sity above 1.05, (11 crystallized acid in 100 of
solution,) and it was divided from water by an
animal membrane, the temperature being + 25
cent, the endosmotic current is directed from
the water towards the acid ; but when, under
the same circumstances, the density of the acid
solution is below 1.05, the current of endos-
mosis is directed from the acid towards the
water, just as we have found it to be with refe-
rence to the oxalic acid. Consequently, ac-
cording to its greater or less density, tartaric
acid presents the phenomenon of endosmosis in
two opposite directions. At the mean density

of 1.05, at a temperature of + 25° cent, it
exhibits no obvious endosmotic phenomena
whatever ; not that there is not reciprocal pe-
netration between the acid and the water, which
are divided by the animal membrane ; but this
reciprocal penetration takes place so equally on
either side, that there is no increase of bulk of
the one fluid at the cost of the other — there is
no endosmosis. The citric acid exhibits pre-
cisely the same phenomena; the point of mean
density, which divides its two opposed endos-
motic capacities, is also very nearly the same,
namely, 1 .05 at a temperature of -\- 25° cent.
These facts induced me to imagine that if the
oxalic acid alone presented the endosmotic cur-
rent directed from the acid towards the water,
this arose from the fact of its solution at + 25°
cent, falling short of the density necessary to
permit the acid solution to cause the endosmo-
tic current to flow from the water towards the
acid.

The preceding observations were made during
the heats of summer. The centigrade thermo-
meter was standing at •+• 25° when I determined
the mean term of density of the solution of tar-
taric acid, above and short of which the endos-
mosis happening between this solution and
water is directed towards the acid. It was of
importance to know whether a depression of
temperature would cause any modification in
these phenomena. I therefore repeated the
same experiments when the temperature was
+ 15° cent, and I was astonished to find that
the mean term of density, of which we have
spoken above, was considerably altered, being
made to move in the direction of the increase
of density of the acid solution. Thus the mean
term of density being 1.05, (11 crystallized
acid to 100 solution,) at a temperature of + 25°
cent, it came to be 1.1, (21 acid to 100 solu-
tion,) at a temperature of +15° of the same
scale ; that is to say, the solution of tartaric
acid, which now occupies the mean term, con-
tains nearly twice as much acid as the solution
which stood at the previous mean term, when
the temperature was ten degrees of the centi-
grade scale higher. This first essay was enough
to lead to the inference that the mean term of
density, which we are now discussing, would
undergo further alterations in the same sense
with further depressions of temperature; and
this was actually found to be the case. At a
temperature of 8£° cent, the solution of tarta-
ric acid, of the density 1.1, was no longer the
solution of mean density dividing the two op-
posed endosmotic currents, as it was when the
temperature was + 15° cent. This solution
then caused the endosmotic current to flow
freely towards the water. I had to increase its
density to 1.15 (30 acid to 100 solution) to
come to the new mean term, beyond which the
current of endosmosis was directed towards the
acid, and within which it was directed towards
the water. With the temperature depressed to
a quarter of a degree cent, above zero, the
solution of tartaric acid, of the density of 1.15,
no longer presented the mean term; this solution
now occasioned endosmosis towards the water,
which indicated that the mean term was to be

ENDOSMOS1S.

107

sought for in a more dense solution of tartaric
acid, and this I actually found in a solution of
the density of 1.21 (40 acid to 100 solution).
Every solution of this acid of greater density
than 1.21, at the temperature of £th of a degree
above zero cent, caused the endosmotic cur-
rent to flow from the water towards the acid,
and every solution of the same acid, under the
density of 1.21, caused the endosmotic current
from the acid towards the water. From all
these experiments it follows that a fall of tem-
perature favours the endosmosis towards the
water, and that a rise of temperature favours
the endosmosis towards the acid. In fact, the
same solution of tartaric acid occasions at one
time endosmosis towards the acid, when the
temperature is high ; at another, endosmosis
towards the water when the temperature is re-
latively low. It would appear from this, that
a depression of temperature renders the solu-
tion of tartaric acid more apt than water to
permeate animal membranes, and that there is
a certain concordance between this capacity of
permeation and the temperature and the den-
sity of the acid solution. This phenonernon,
at first sight, appears analogous to that which
M. Girard discovered,* in regard to the com-
parative flow of a solution of nitre and of pure
water through a capillary glass tube. M. Girard
found that, at a temperature of -J-100, a solu-
tion of one part of nitrate of potash in three
parts of water flows more rapidly than pure
water through a capillary glass tube, whilst the
same solution flows more slowly than water
when the temperature is above -{- 10°. To
discover whether this apparent analogy was
well founded or not, I made an experiment to
ascertain the relative duration of the flow
through a capillary glass tube of a given mea-
sure of pure water, and a like measure of a
solution of tartaric acid, the density of which
was 1.05 (21.8 parts acid, 100 solution.) The
temperature being + 7° cent. I found that
fifteen centilitres of water flowed through a ca-
pillary glass tube in 157 seconds; but the
same quantity of the solution of tartaric acid
required 301 seconds to pass through the same
capillary tube. There is consequently no ac-
tual analogy to be established between the re-
sults of the experiments of M. Girard and the
fact of the endosmosis towards the water, which
takes place when at a temperature of +7°
cent, a solution of tartaric acid of the den-
sity of 1.105, is separated from a volume of
pure water by a piece of an animal membrane.
It may be as well if I here state that when a
solution of one part of nitrate of potash in three
parts of water was separated by a piece of
bladder from pure water, I have always ob-
served the endosmotic current directed towards
the solution ; the temperature might be at
zero, or -f- 10°, or higher, the same phenome-
non always occurred. This is sufficient to
prove that endosmosis is governed by laws en-
tirely different from those that preside over
simple capillary filtration. I add, that the
solution of tartaric acid, of 1.105 density, hav-

* Mem. de 1'Acad. des Sciences, 1816.

ing a viscidity nearly the double of that of
water, and passing, nevertheless, by endosmo-
sis into the latter fluid, when it is separated
from it by an animal membrane, and the tem-
perature is + 7° cent, also proves that endos-
mosis does not generally depend on the visci-
dity of fluids.

Acid solutions are the only fluids which have
yet been found to occasion the endosmotic cur-
rent to flow towards water when separated from
this fluid by an animal membrane. The whole
of the acids, without exception, exhibit this
phenomenon, which was long overlooked by
me, from its having been confounded with
another phenomenon, namely, the abolition of
endosmosis. I have in fact shown, in a work
already before the public,* that all fluids which
act chemically on the membrane of the endos-
mometer, put an end, with greater or less cele-
rity, to the phenomenon of endosmosis, — it
goes on for some time, but it never fails to
cease at length. Sulphuric acid, above all the
other acids, has the property of putting an end
to endosmosis. This acid, poured into the en-
dosmometer, sinks by virtue of its simple gravity
towards the lower water, filtering mechanically
through the membrane placed between it and
the water. If the position of the two fluids be
reversed, the endosmometer being charged with
water, and the sulphuric acid placed externally
and on the lower level, the water still sinks to-
wards the acid, passing in its turn mechani-
cally through the membranous septum of the
instrument, rendered incapable of effecting en-
dosmosis. From these experiments I was led
at first to conclude that sulphuric acid was in-
active as regards endosmosis ; in other words,
was incapable of exhibiting or producing this
phenomenon. I have since found, however,
that the sulphuric, like all the other acids, has
the faculty of exerting endosmosis in the two
opposite directions, but always during a very
brief space of time only. Thus the tempera-
ture being + 10° cent., sulphuric acid, of the
density of 1.093, separated from water by a
piece of bladder, the endosmotic current is
directed from the water towards the acid, but
the phenomenon lasts only for a short time ;
the current soon ceases, and if the acid be on
the higher level, it then begins to sink by sim-
ple mechanical filtration towards the water.
At the same temperature of + 10° cent., the
sulphuric acid attenuated to 1.054 being placed
in the endosmometer, and the reservoir and a
part of the tube being plunged in water, en-
dosmosis is established, but in this case the
current is from the acid towards the water, so
that the acid liquor sinks in the tube ; and that
this sinking is due to endosmosis is demon-
strated by the fact of the acid continuing to
sink in the tube of the endosmometer a consi-
derable way below the level of the external
water, and not stopping short when the level is
obtained, as it does when the descent is owing
to simple mechanical filtration. In this expe-
riment, as in the one detailed immediately be-

* Nouv. Rechcrches sur 1'Kndosmose, &c. p. 25.
See also my Memoir in the 49th vol. of the Aunales
de Chiinic, p. 415.

108

ENDOSMOSIS.

fore it, the endosmosis towards the water is
abolished, and then the column in the endos-
mometer begins to rise again slowly, until the
level of the external and included fluids corre-
spond. We, therefore, see that at a tempera-
ture of + 10° cent., sulphuric acid, of the
density of 1.093, presents the current of endos-
mosis from the water towards the acid ; whilst
the density being 1.054, the endosmosis is
from the acid towards the water. Between
these two opposite endosmotic currents there
necessarily exists a mean when no phenomena
of the kind occur. This mean, the tempera-
ture continuing -\- 10°, I find to belong to sul-
phuric acid of the density of 1.07. The two
fluids, divided by the animal membrane of the
endosmometer, penetrate one another athwart
the septum reciprocally and in equal measure,
so that the contents of the endosmometer re-
main for a certain time at the same height in
the tube of the instrument ; subsequently the
contained fluid begins to sink in consequence
of the cessation of all endosmosis. These ex-
periments were necessarily undertaken when
the temperature was moderate or low ; the
phenomena detailed would not else have been
appreciable; for in a warm atmosphere the
abolition of endosmosis by sulphuric acid is
accomplished so rapidly, that it is with diffi-
culty the slight current established in the first
instance can be observed.

Sulphurous acid, of the density 1.02, sepa-
rated from water by an animal membrane, only
exhibits endosmosis towards the water ; this
endosmosis is pretty active at first ; but after
the lapse of a brief interval the current ceases,
just as it does with the sulphuric acid. These
results I came to after a number of experi-
ments, the temperature being at one time + 5°,
and at another + 25° cent.

Formerly I regarded the hydrosulphuric acid
as inactive in regard to endosmosis ; I assimi-
lated it, in this respect, with the sulphuric acid.
The fact, however, is that, like the sulphuric
acid, it has the property of producing endos-
mosis. The acid I employed was of the den-
sity of 1.00623. With a piece of bladder be-
tween this acid and water, the endosmosis was
constantly towards the water. This conclusion
was not influenced by variations of tempera-
ture between Jf 4° and +25° cent. The ac-
tion was somewhat protracted, but the endos-
mosis never failed to cease after a certain time,
as in the case of the sulphuric acid.

The nitric acid of considerable density exhi-
bits endosmosis towards the acid when sepa-
rated from water by a piece of animal mem-
brane. Thus, at a temperature of + 10° cent.
this acid (density 1.12 or higher) presents the
current flowing towards the acid. Under the
same circumstances, but of the density of 1.08,
the endosmosis is towards the water. Of the
density 1.09, the mean term between the two
opposite endosmoses is obtained. At higher
temperatures the nitric acid very speedily puts
an end to the phenomena of endosmosis, espe-
cially when its density is not very high, so that
it becomes difficult to perceive the very tran-
sient currents produced in the first instance.

The hydrochloric is the most potent of all
the mineral acids in directing the current of
endosmosis from the water towards the acid.
Its density must be considerably reduced before
it offers the direction of the current changed, or
from the acid towards the water. At a tempe-
rature of + 22° cent, for instance, the hydro-
chloric acid has to be brought, by the addition
of water, to a density no higher than 1.003,
before it presents the endosmosis flowing to-
wards the water, from which, as understood, it
is divided by a layer of animal membrane. Of
greater density the endosmosis is towards the
acid. When the temperature is lower than
+ 22°, the same acid, of greater density, ac-
quires the property of causing endosmosis to-
wards the water. Thus, with the centigrade
thermometer at -f- 10°, I found that hydro-
chloric acid of 1.017 density presented the
mean term between the two opposite endosmo-
ses. At the same temperature hydrochloric
acid, of 1.02 density, presented endosmosis to-
wards the acid, and of 1.015 density, endos-
mosis towards the water. Under a higher
temperature, however, and of the latter density
(1.015), the endosmosis was towards the water,
so that a depression of 12° cent, in tem-
perature causes the mean term of the density of
hydrochloric acid, which separates the two op-
posed endosmoses, to rise from that of about
1.003 to that of 1.027; that is to say, the
quantity of acid added to the water must be
increased almost six-fold to produce the same
effects.

In the present state of our knowledge, we
find it quite impossible to give any explanation
of the remarkable phenomenon exhibited in the
changes of direction of the endosmotic currents
according to the degree of density of the acid
and the temperature. The singularity of this
phenomenon will appear the greater when the
following observation is takon into the account.
Hitherto it was always by a layer of animal
membrane that I separated the acid from the
water. Instead of the animal membrane I
now tried the effect of one of vegetable origin.
We have seen above that oxalic acid, whatever
its density and under whatever temperature,
when separated from water by an animal mem-
brane, always exhibited endosmosis from the
acid towards the water. I filled a pod of the
colutea arborescens, which being opened at one
end only and forming a little bag, was readily
attached by means of a ligature to a glass tube^
with a solution of oxalic acid,, and having
plunged it into rain-water, endosmosis was ma-
nifested by the ascent of the contained acid
fluid in the tube ; that is to say, the current
flowed from the water towards the acid. The
lower part of the leek (allium porrum) is en-
veloped or sheathed by the tubular petioles of
the leaves. By slitting these cylindrical tubes
down one side, vegetable membranous webs, of
sufficient breadth and strength to be tied upon
the reservoir of an endosmometer, are readily
obtained. An endosmometer, fitted with one
of these vegetable membranes, having been
filled with a solution of oxalic acid, and then
plunged into rain-water, the included fluid rose

ENDOSMOSIS.

109

gradually in the tube of the endosmometer, so
that the endosmosis was from the water towards
the acid, the reverse of that which takes place
when the endosmometer is furnished with an
animal membrane. The tartaric and citric
acids of densities below 1.05, and at a tempe-
rature of + 25° cent, exhibit endosmosis to-
wards the water with an animal membrane ;
but with a vegetable membrane the case is
altered ; the endosmosis being then directed
from the water towards the acid. I have tried
solutions of tartaric acid, decreasing gradually
in density from 1.05 (11 tartaric acid to 100
solution) to a density so low as 1.0004, (1 tar-
taric acid, 1000 solution,) and always seen the
endosmosis towards the acid. A gradual fall
in the temperature from -j- 25° to near zero did
not affect the result.

Sulphuric acid of 1.0274 density and at a
temperature of + 4° centes* when separated
from water by a vegetable membrane, exhibited
endosmosis towards the acid ; separated by an
animal membrane, however, the endosmosis
was towards the water.

Hydrosulphuric acid (density 1.00628) sepa-
rated from water by an animal membrane,
always shows endosmosis towards the water j
but separated by a vegetable membrane, the
current is as uniformly towards the acid. The
experiment from which I deduce this result
was only performed at a temperature of -f- 5°.

Sulphurous acid (density 1.02) separated
from water by an animal membrane, exhibits
an active endosmosis towards the water, at
every temperature from zero up to -f- 25° centes.
(I have made no experiments on endosmosis at
higher temperatures.) When sulphurous acid,
of the density of 1.02, is separated from water
by a layer of vegetable membrane, it presents
neither endosmosis towards the acid nor endos-
mosis towards the water ; it then appears to be
under the influence of the simple laws presiding
over the flow of fluids by filtration : there is
abolition of endosmosis. I was anxious to see
what endosmotic effects it would produce with
an endosmometer closed with a layer of .baked
clay, and it was not without surprise that I saw
the current flowing vigorously towards the
water. I had put the acid into the reservoir of
the endosmometer ; and the included fluid rose
to a considerable height in the tube of the in-
strument, which I had taken care to immerse
in water to the place where the acid rose in the
tube. The acid continued to sink in the tube
of the endosmometer for four hours, and had
then fallen to about 12 centimetres below the
level of the external water ; it subsequently be-
gan to rise slowly in the tube, and finally
gained the level of the external water, where it
remained. It was obvious that the sulphurous
acid had sunk in the tube below the level of the
water, in consequence of endosmosis towards the
water, and that its subsequent rise to the level
of the water was due to simple filtration through
the membrane. Endosmosis had then ceased.
Sulphuric acid, diluted with water to the den-
sity of 1.0549, exhibits the same phenomena as
sulphurous acid when separated from water by
a lamina of baked clay : it first occasions en-

dosmosis towards the water, but after some
minutes this endosmosis ceases, and is not re-
placed by endosmosis of an opposite nature ;
simple filtration from the effect of gravity is all
that then takes place; endosmosis of each kind
is put a stop to. Hydrosulphuric acid, sepa-
rated from water by a lamina of baked clay,
gives the same results precisely as the sulphu-
ric acid. This phenomenon is rendered still
more strange by the fact of its not being general.
Thus the oxalic acid exhibits endosmosis to-
wards the acid when this is separated from
water by a lamina of baked clay. This fact I
ascerlained under a variety of temperatures
from + 4° to -h 25° centes. and with solutions
of the acid of" as great density as could be ob-
tained at each temperature, as well as with so-
lutions of very low density. The tartaric acid
also presents endosmosis towards the acid when
separated from water by a lamina of baked
clay. I had formerly found * that a little sul-
phuric or hydrosulphuric acid added to gum-
water, causes the current of endosmosis to cease
flowing from the water towards the gum-water,
so that the latter fluid, instead of rising in the
tube of the endosmometer, begins gradually to
falL I then attributed this phenomenon to the
abolition of endosmosis ; but it is evident that
in certain cases it is owing to the current of en-
dosmosis changing its direction and flowing
from the acid towards the water. Thus, with
reference to the acidulated gum-water, of which
I have just spoken, when placed above water,
from which it was separated by an animal
membrane, it fell in the stem of the endosmo-
meter and flowed towards the water, either from
the abolition of endosmosis, and in virtue of its
gravity, or in consequence of the establishment
of an endosmotic current towards the external
water. Experiment can alone determine which
of these two causes is the efficient one of the
descent of the acidulated fluid in the stem of
the endosmometer. The whole of the acids
used of such density as comports with the pro-
duction of endosmosis towards water, and in
sufficient quantity, are adequate to overcome
the disposition which any fluid may possess to
produce endosmosis in the opposite direction.
Here is a case in illustration of this point. The
power of sugar-water in causing endosmosis is
very great, as I have shown already. Water
holding no more than one-sixteenth of its
weight of sugar in solution causes rapid endos-
mosis from the water towards the solution. But
I have found that, by adding to this sweet
liquid a quantity of oxalic acid equal in weight
to that of the sugar which it holds in solution,
the direction of the endosmotic current is im-
mediately changed ; the flow is no longer from
the water towards the solution, but from the
sweet-sour solution towards the water, so that
the oxalic acid may be said to compel the sac-
charine solution to which it is added to take
the direction of the endosmotic current which
is proper to it. Here it is the viscid and dense
fluid, with little power of capillary ascent,
which traverses the animal membrane with

* Nouv. Rech. sur 1'Endosmose, p. 8.

110

ENDOSMOSIS.

greater ease and more rapidity than pure water.
This may be added to the facts set forth already
to prove, in the most decided manner, that the
greater power of permeation manifested by one
of the two fluids in experiments on endosmosis
does not follow from any greater viscidity it
may possess than the fluid opposed to it. In
sixteen parts of water I dissolved two parts of
sugar and one part of oxalic acid. In this so-
lution I plunged the reservoir of an endosmo-
meter, closed with a piece of bladder, and filled
with pure water : this did not show any diffe-
rence of level in the tube during the two hoius
that I continued the experiment. There was
consequently no endosmosis. Nevertheless, I
found that the water contained in the endosmo-
meter contained a large quantity of oxalic acid,
whether tested by the addition of lime-water
or by the palate, which last also detected the
presence of sugar. Thus the sweet-sour fluid,
exterior to the endosmometer, had penetrated
the water contained within its cavity. If this
circumstance was proclaimed by no increase in
the volume of the water, this undoubtedly was
owing to the included water having lost by the
descending counter-current an amount exactly
equal to the amount it had gained by the in-
ward or ascending current. There was no en-
dosmosis in the sense in which I use that word,
although it is certain that there were two active
antagonist currents athwart the membrane which
separated the two fluids. It must not be lost
sight of that I only give the title of endosmosis
to a stronger current opposed to a weaker
counter-current , antagonists to each other, and
proceeding simultaneously athwart the septum,
dividing the two fluids which are made the
subjects of experiment. The instant these two
antagonist currents become equal, there is no
accumulation of fluid on one side, and there is
then no longer any effort at dilatation or im-
pulsion; in a word, there is no longer any
endosmosis.

The opposite directions in which the endos-
mosis towards water, effected by acids of deter-
minate density, and the endosmosis from water
occasioned by other fluids, would lead us to
conclude that in placing such a fluid as gum-
water or sugar-water in an endosmometer fur-
nished with an animal membrane, and in con-
tact externally with an acid solution of appro-
priate density, we should have a much more
rapid endosmosis towards the included fluid
than if it were pure water in which the endos-
mometer was plunged ; and this in fact is what
I have found to be the case by experiment.
Into an endosmometer, closed with a piece of
bladder, I poured a solution of five parts of
sugar in twenty-four parts of water. Having
plunged the reservoir of the instrument into
water, I obtained in the course of an hour an
ascent of the included fluid, which may be re-
presented by the number 9. The reservoir of
the same endosmometer filled with a portion of
the same saccharine solution, having been
plunged into a solution of oxalic acid, the den-
sity of which was 1.014, (3.2 parts acid to 100
solution,) I obtained in the course of an hour
an ascent of the included fluid, which required

to be represented by the number 27. The
substitution of a solution of oxalic acid for
pure water consequently caused the amount of
endosmosis in the same interval of time to be
tripled. I obtained like results with the tarta-
ric and citric acids, employed of the densities
required to enable them to produce endosmosis
towards water. From these experiments it
would appear that water, charged with a small
proportion of one of the acids, of which men-
tion has been made, possesses a power of pene-
tration athwart animal membranes greater than
that inherent in pure water. But a direct ex-
periment, detailed in an earlier part of this
paper, proves that this is not the case ; pure
water used by itself is still the fluid that pos-
sesses the greatest power of penetrating through
animal membranes. If, consequently, in those
experiments which I have last described, the
water charged with acid passed more readily
and more copiously into the saccharine solu-
tion than pure water, this happens undoubtedly
from other causes or conditions which I cannot
take upon me to explain, but which appear to
be : 1st. A reciprocal action between the two
heterogeneous fluids, an action which modifies,
which even completely inverts the natural
power of penetration possessed by each of the
fluids when employed singly ; 2d. A particular
action of the membrane upon the two fluids
which penetrate it, an action which, with the
animal membrane, gives the stronger current
or current of endosmosis to the acid solution of
due density, and the weaker current or coun-
ter-current of exosmosis to the pure water. It
seems to me impossible to deny this peculiar
action to the animal membrane, when we see
that a vegetable membrane in the same circum-
stances produces endosmotic phenomena di-
rectly the reverse. The peculiar influence of
the membranous septum is likewise manifested
in a very striking way in the experiment in
which I have shown that the current of endos-
mosis flows from water towards alcohol when
these two fluids are divided by an animal
membrane, and, on the contrary, that the cur-
rent of endosmosis flows from alcohol towards
water when the two fluids are separated by a
membranous septum of caoutchouc.

Endosmosis, in the present order of things,
is a phenomenon restricted to the realm of or-
ganization ; it is nowhere observed in the inor-
ganic world. It is in fact only among organ-
ized beings that we observe fluids of different
density separated by thin septa and capillary
pores ; we meet with nothing of the same kind
among inorganic bodies. Endosmosis, then,
is a physical phenomenon inherent exclusively
in organic bodies, and observation teaches us
that this phenomenon plays a part of the high-
est importance in their economy. It is among
vegetables especially that the importance of the
phenomenon strikes us; I have, in fact, de-
monstrated that it is to endosmosis that are
due, in great part, the motions of the sap, and
particularly its very energetic ascending motion.
I have also shown that all the spontaneous mo-
tions of vegetables are referable to endosmosis.
The organic vegetable tissue is composed of a

ENTOZOA.

Ill

multitude of agglomerated cells mingled with
tubes. The whole of these hollow organs, the
parietes of which are extremely thin, and which
contain fluids the densities of which vary, ne-
cessarily make mutual exchanges of the4r con-
tents by way of endosmosis and exosmosis.
Nor cari we suppose but that the same pheno-
mena take place among the various cells and
cavities exhibited by the organism of animals.
But the effects of endosmosis, its influence on
the physiological phenomena presented by ani-
mals, has yet to be determined ; and here, un-
doubtedly, the physiologist has an ample field
before him for inquiry. I shall only say in
conclusion, and with reference to this very in-
teresting part of the subject, that I have satis-
fied myself that it is to endosmosis that the
motions of the well-known spiral spring tubes of
the milt of the cuttle-fish, when put into water,
are owing.

( H. Dutrochet.)

ENTOZOA, (EFTO?, intus, g«o,, animal,)
fXtut>0e? ffrgoyyvhot, ityuvSs? wXa-mat, acrxa-
£»&£?, Arist. et Antiq. Vers Intestinaux, Cuv.
Entelmintha, Splanchnelmintha, Zeder.

The term ENTOZOA, like the term Infusoria,
is indicative of a series of animals, associated
together chiefly in consequence of a similarity
of local habitation ; which in the present class
is the internal parts of animals.

In treating therefore of the organization of
these parasites, we are compelled to consider
them, not as a class of animals established
on any common, exclusive, or intelligible cha-
racters, but as the inhabitants of a peculiar dis-
trict or country.

They do not, indeed, present the types of so
many distinct groups as those into which the
naturalist finds it necessary to distribute the
subjects of a local Fauna, yet they can as little
be regarded as constituting one natural assem-
blage in the system of Animated Nature.
And it may be further observed that as the
members of no single class of animals are con-
fined to one particular country, so neither are
the different natural groups of Entozoa exclu-
sively represented by species parasitic in the
interior of animal bodies. Few zoologists, we
apprehend, would dissociate and place in sepa-
rate classes, in any system professing to set
forth the natural affinities of the animal king-
dom, the Planaria from the Trematoda, or the
Vibrionidte from the microscopic parasite of the
human muscles.

In the present article it is proposed to divide
the various animals confounded together under
the common term of Entozoa or Entelmintha
into three primary groups or classes; and, as in
speaking of the traits of organization common
to each, it becomes not only convenient but
necessary to have terms for the groups so
spoken of, they will be denominated Protel-
mintha, Sterelmintha, and Ccelelmintha respec-
tively.

It may be observed that each of these
groups, which here follow one another in the
order of their respective superiority or com-
plexity of organization, has been indicated,

and more or less accurately denned by pre-
vious zoologists. After the dismemberment
of the Infusoria of Cuvier into the classes
Polygastrica and Rotifera, which resulted
from the researches of Professor Ehrenberg
into the structure of these microscopic beings,
there remained certain families of Animalcules
which could not be definitely classed with
either: these were the Cercariadte and Vibrio-
nidte. Mr. Pritchard, in his very useful work
on Animalcules, has applied to the latter fa-
mily the term Entozoa, from the analogy of
^heir external form to the ordinary species of
intestinal worms ; and it is somewhat singular
that a species referrible to the VibrionicLe
should subsequently have been detected in the
human body itself. Premising that the tribe
Vibrionida as at present constituted is by no
means a natural group, and that some of the
higher organized genera, as Anguillula, are re-
ferrible to the highest rather than the lowest of
the classes of Entozoa, we join the lower organ-
ized genera, which have no distinct oviducts, and
which, like the parasitic Trichina, resemble the
foetal stage of the Nematoid worms, with the
Cercariad<£, in which the generative apparatus
is equally inconspicuous; and these families,
dismembered from the Infusoria of Lamarck,
constitute the class Protelmintha, the first
or earliest forms of Entozoa.

The second and third classes correspond to
the two divisions of the class Intestinalia, in
the ' Regne Animal ' of Cuvier, and which are
there respectively denominated * Vers Intesti-
naux Parenchymateux,' and * Vers Intestinaux
Cavitaires.' The characters of these classes will
be fully considered hereafter; and in the mean-
while but little apology seems necessary for in-
venting names expressive of the leading distinc-
tion of each group as Latin equivalents for the
compound French phrases by which they have
hitherto been designated. EXf-u»? appears to
have been applied by the Greeks to the in-
testinal worms generally, as Aristotle speaks
of £tyu>0£? nrXaTEtai, intestinalia lata, and
e?ye»>0E? c-r^oyyyAai, intestinalia teretia. In
framing the terms Sterelmintha and Calelmin-
tha, from styuv? o-rs^ea, a solid or parenchy-
matous worm, and iX/xtv? xo»X»j, a hollow or
cavitary worm, I follow the example of Zeder,
and omit the aspirate letter. It may be ob-
served by the way that Zeder's term Splanchnel-
mintha, besides including animals which are
developed in other parts than the viscera, is,
like the term Entozoa, open to the objection of
being applied to a series of animals which, ac-
cording to their organization, belong to distinct
classes.

The limits and object of the present article
obviously forbid an extensive or very minute
consideration of the anatomical details of each
of these classes of animals, and we are com-
pelled to confine ourselves almost exclusively
to such illustrations of their respective plans
of organization as are afforded by the species
referrible to each which inhabit the human body.

If a drop of the secretion of the testicle be
expressed from the divided vas deferens in
a recently killed mammiferous animal, which

112

EMTOZOA.

has arrived at maturity, and be diluted with
a little pure tepid water and placed in the
field of a microscope, a swarm of minute
beings resembling tadpoles will be observed
moving about with various degrees of velo-
city, and in various directions, apparently by
means of the inflexions of a filamentary caudal
appendage. These are the seminal animalcules,
Zoosperms, or Spermatozoa (Jig, 51): and, as
it is still undetermined whether they are to be
regarded as analogous to the moving filaments
of the pollen of plants, or as independent or-
ganisms, it has been deemed more convenient
to consider them zoographically in the present
article as members of the class Entozoa.

The body to which the tail is attached is
of an oval and flattened or compressed form,
so that, when viewed sideways, the Zoosperm
appears to be a moving filament like a minute
Vibrio. It is this compressed form of the
body which principally distinguishes the Sper-
matozoa or seminal Cercarits^ from the true
CercaritR of vegetable infusions, in which the
body is ovoid or cylindrical ; the caudal ap-
pendage of the Spermatozoa is also propor-
tionally longer than in the Cercaria.

In some species of the latter genus an oral
aperture and ocelliform specks of an opake
red colour have been obsprved on the anterior
part of the body, and they manifest their sen-
sibility to light by collecting towards the side
of the vessel exposed to that influence. In
the Zoosperms, which are developed exclu-
sively in the dark recesses of animal bodies,
the simplest rudiments of a visual organ would
be superfluous; they are, in fact, devoid of
ocelli, and even an oral aperture has not yet
been detected in these simplest and most mi-
nute of Entozoa. In neither the Zoosperms
nor the Cercarue has the polygastric struc-
ture been determined. On the contrary, some
of the non-parasitic species, as the Cercaria
LemnaKj are stated to have ' a true alimen-
tary canal, not polygastric.' *

The Spermatozoa are not, however, the only
examples of the present order of Protelm'mtha
which have their habitat in the interior of living
animals ; many of the Entozoa themselves have
been observed to be infested by internal para-
sites, which are referrible by their external form
to the Cercariadee.

Although no distinct organs of generation
have been detected, there is reason to suspect
that the Spermatozoa are oviparous : they are
also stated to propagate by spontaneous fission ;
the separation taking place between the disc of
the body and the caudal appendage; each of
which develope the part required to form a
perfect whole.

The Zoosperms of each genus of animals
present differences of form or proportion, and
frequently also differences of relative size as
compared to the animal in which they are deve-
loped ; thus, in the figures subjoined, which
are all magnified in the same degree, the
Zoosperm from the Rabbit is nearly as large as
that from the Bull, (jig. 51.)

* Pritchard's Animalcules, p. 184.

Fig. 51.

Bull.

Rabbit.

Silk-worm Moth.
Fig. 52.

::S& C

Developinent of Sper
matozoa, Bunting.

They appear to be
formed in the seminal
secretion under similar
laws to those which pre-
side over the develop-
ment of other Entozoa
in the mucous secretion
of the Intestines, &c.,but
are more constant in their
' existence, and must there-
fore be regarded as fulfil-
ling some more important
office in the economy of
the animal in which they
exist.

They are not found in
the seminal passages or
glands until the full pe-
riod of puberty ; and in
some cases would seem
to be periodically deve-
loped. In the Hedgehog
and Mole, which exhibit
a periodical variation in
the size of the testes in a
well-marked degree, the
Spermatozoa are not ob-
servable in those glands
during their state of
quiescence and partial
atrophy. Professor Wag-
ner* examined the testes
of different Passerine
Birds in the winter sea-
son, when those bodies
are much diminished in
size. (See vol.i. p. 354,
fig. 183.) They then con-
tained only granular sub-
stances, without a trace of
the Spermatozoa. When
the same bodies were ex-
amined in spring, they
were found to contain
spherical granules of dif-
ferent sizes and appear-
ances, (A, B, fig. 52,)
which led to the suppo-
sition that they were the
ova of the Spermatozoa in
different stages of deve-
lopment, and capsules
containing each a nume-
rous group of Sperma-
tozoa (C) were also pre-
sent; whence it would
appear that many of these
animalcules were deve-
loped from a single ovum.
In the semen contained
in the vasa deferentia the
Spermatozoa (D) were in
great numbers, having
escaped from their cap-
sules ; they exhibit a re-
markable rotation on their

* Mailer's Archiv. 1836,
p. 225.

ENTOZOA.

113

axis, which continues for five or ten minutes after
the death of the bird in which they are developed.
Some have supposed that these animalcules
were the result of a putrefactive process, but
this is disproved by their presence in testicles
which have been removed from living animals,,
and by their ceasing in fact to exist when the
seminal secretion begins to undergo a decom-
position. Their extraordinary number is such
that a drop of semen appears as a moving mass,
in which nothing can be distinguished until it
has been diluted as before-mentioned, when
the animalcules are seen to disengage them-
selves and commence their undulatory move-
ments. By means of the continual agitation
thus produced the chemical elements of the
fecundating fluid are probably kept in a due
state of admixture. By the same movements
the impregnating influence of the semen may
be carried beyond the boundary which it
reaches in the female organs from the expulsive
actions of the coitus. It has been conjectured
that from the rapid and extensive multiplication
of these animalcules they may contribute to pro-
duce the stimulus of the rut. But the con-
sideration of the part which the Zoosperms
may play in generation belongs to the Physio-
logical history of that function, and would
lead to discussions foreign to the present
article, which treats of their form and structure
simply as the parasites of animal bodies.

In the human subject the form of the Zoo-
sperm is accurately represented in fig. 51.

Among the cold-blooded Reptiles the Zoo-
sperms of the Frog (fig- 51) have been ex-
amined with most attention, and have been
the subject of interesting experiments in the
hands of Spallanzani and Dumas.

The milt or developed testicle of the osseous
Fishes abounds with moving bodies of a glo-
bular form. In the Shark and Ray the Zoo-
sperms are of a linear and spiral form.

The molluscous animals are favourable sub-
jects for the examination of the present tribe
of Entozoa on account of the great relative
size of the parasites of the seminal secretion.
They are mostly of a filamentary form, and
have long been known in the Cephalopods.
The Zoosperms of the Snail (Helix Pomatia)
present an undulated capillary body, and move
sufficiently slowly to permit their being readily
followed by the eye.

The Spermatozoa have been detected and
described in the different classes of the Arti-
culate Animals. In Insects they are of a fine
capillary form, and are generally aggregated in
bundles. They abound in the semen of the
Anellides and Cirripeds; lastly, these parasites
have been found to exist in vast numbers in the
spermatic tubes of the higher organized En-
tozoa themselves.

The second tribe of Protelmlntha includes
those cylindrical, filiform, eel-like, microscopic
Animalcules which abound in decayed vege-
table paste, stale vinegar, &c. together with
others which have attracted particular attention
by the destructive waste caused by certain spe-
cies which are parasitic on living vegetables.
These animalcules are termed Vibrionida from

VOL. II.

their darting or quivering motion. They differ
from the polygastric Infusories, not only in
the absence of internal stomachs but also of
external cilia, which is inferred by their not
exciting any currents when placed in coloured
water. They present a higher grade of organi-
zation than the Cercarian tribe in the presence
of a straight alimentary canal, which is re-
markably distinct in some of the higher forms
of the group, as the Gordioides and Oxyu-
roides of Bory St. Vincent.

The higher organized Vibriones have distinct
generative organs, and are ovo-viviparous.

In the species of Vibrio which infests the
grains of wheat and occasions the destructive
disease called Ear-cockle or Purples, Mr. Bauer
found the ova arranged between the alimentary
canal and the integument, in a chaplet or
moniliform oviduct which terminated by a
bilabiate orifice at a little distance from the
caudal extremity of the body. The ova are
discharged at this orifice in strings of five or
six, adhering to each other. Each egg is about
5^jth of an inch long, and g^th or g^th in di-
ameter: and they are sufficiently transparent
to allow of the young worm being seen within :
and the embryo, in about an hour and a half
after the egg is laid, extricates itself from the
egg-coverings. Of the numerous individuals
examined by Mr. Bauer, not any exhibited
external distinctions of sex, and he believes
them to be hermaphrodites.

In the Anguillula aceti, or common Vinegar-
eel, Bory St. Vincent has distinguished indi-
viduals in which a slender spiculum is pro-
truded from the labiate orifice corresponding
to that above described from which the ova
are extruded ; these individuals he considers
to be males ; they are much less numerous
than the females; are considerably smaller;
and the internal chaplet of ova is not dis-
cernible in them. In the female the ova are
arranged in two series on each side of the
alimentary canal, and the embryo worms are
usually seen to escape from the egg-coverings
while yet within the body of the parent, and
to be born alive. Ehrenberg figures the two
sexes of Anguillula fluviatilis in his first trea-
tise on the Infusoria (tab. vii. fig. 5.*) The
granular testis and intromittent spiculum, which
is single, are conspicuous in the male ; the ova
in the female are large and arranged as in
Anguillula aceti. Such an organization, it is
obvious, closely approximates these higher
Vibrionidae to the nematoid Entozoa, as the
Ascarides and Oxyuri, and further researches
on this interesting group will doubtless lead to
the dismemberment of the Oxyuroid family
from the more simple Vibrionida, as the
genera Bacterium, Spirillum, and Vibrio, with
which they are at present associated.

To the group composed of the three last-
named genera, the microscopic parasite of the
human muscles, termed Trichina Spiralis, is
referrible.f

* Organisation, systematik und georaphisches
Verhaltniss der Infusionthieschen, 1&30.

t Zool. Trans, vol. i. r>. 315, and Zool. Pro-
ceedings, for February, 1835.

I

114

ENTOZOA.

Fig. 53.

This singular Entozoon I discovered in a
portion of the muscles of a male subject, which
was transmitted to me for examination, at the
beginning of 1835, by Mr.Wormald, Demon-
strator of Anatomy at St. Bartholomew's Hos-
pital, on account of a peculiar speckled ap-
pearance of those parts. This state of the
muscles had been noticed by that gentleman
as an occasional but rare occurrence in subjects
dissected at St. Bartholomew's in several pre-
vious years.

The portion of muscle was beset with minute
•whitish specks, as represented in the subjoined
cut (Jig. 53) : and in fourteen subsequent
instances which have
come to my knowledge
of the presence of this
entozoon in the human
subject, the muscles
have presented very
similar appearances,
The specks are produ-
ced by the cysts con-
taining the worm, and
vary, as to their dis-
tinctness, according to
their degrees of opacity,
whiteness, and hard-
ness.

The cysts are very
readily detected by
gently compressing a
thin slice of the infect-
ed muscle between two
pieces of glass and ap-
plying a magnifying power of an inch focus.
They are of an elliptical figure, with the extremi-
ties more or less attenuated, often unequally
elongated, and always more opaque than the body
or intermediate part of the cyst, which is, in
general, sufficiently transparent to shew that
it contains a minute coiled-up worm.

The cysts are always arranged with their
long axis parallel to the course of the mus-
cular fibres, which probably results from their
yielding to the pressure of the contained worm,
and becoming elongated at the two points
where the separation of the muscular fasciculi
most readily takes place, and offers least re-
sistance ; and for the same reason one or both
of the extremities of the cyst
Fig. 54. become from repeated pressure
and irritation thicker and more
opaque than the rest. That the
adhesive process in the cellular
tissue, to which I refer the for-
mation of the cyst, was most
active at the extremities of the
cyst is also evinced by the closer
adhesion which these parts have
to the surrounding cellular tissue.
The cysts measure generally
A separateCyst about 5\jth of an inch in their
longitudinal, and -j^thof an inch
in their transverse diameters :

like other cysts which are the

tranparent resu^ OI tne adhesive inflamma-
coats, magni- i}On> tney have a rough exterior,
jied. and are of a laminated texture.

Cysts of the Trichina

Spiralis in situ, natural

site.

of the Trie hi-
na. which is

The innermost layer (Jig. 54), however, can
sometimes be detached entire, like a distinct
cyst, from the outer portion, and its contour
is generally well marked when seen by trans-
mitted light. By cutting off the extremity of the
cyst, which may be done with a cataract needle
or fine knife, and gently pressing on the opposite
extremity, the Trichina and the granular secre-
tion with which it is surrounded, will escape ;
and it frequently starts out as soon as the cyst
is opened. But this delicate operation requires
some practice and familiarity with microsco-
pical dissection, and many attempts may fail
before the dissector succeeds in liberating the
worm entire and uninjured.

When first extracted, the Trichina is usually
disposed in two or two and a half spiral coils :
when straightened out (which is to be done
with a pair of hooked needles, when the sur-
rounding moisture is so far evaporated as that
the adhesion of the middle of the worm to the
glass it rests upon shall afford a due resistance
to a pressure of the needle upon the extremi-
ties), it measures ^th of an inch in length and
T^th °f an inch in diameter, and now requires
for its satisfactory examination a magnifying
power of at least 200 linear admeasurement.
The worm (fig. 55) is cylindrical and fili-
form, terminating obtusely
Fig. 55. at both extremities, which

are of unequal sizes ; taper •
ing towards one end for
about one-fourth part of its
length, but continuing of
uniform diameter from that
point to the opposite ex-
tremity.

Until lately it was only
at the larger extremity that
Trichina spiralis I have been able to distin-
magnijied. guish an indication of an

orifice, and this is situated
in many specimens in the centre of a transverse,
bilabiate, linear mouth, («, Jig. 54.)

A recently extracted living worm, when ex-
amined by a good achromatic instrument be-
fore any evaporation of the surrounding fluid
has affected the integument, presents a smooth
transparent exterior skin, inclosing apparently
a fine granular parenchyma. It is curious to
watch the variety of deceptive appearances of
a more complex organization which result from
the wrinkling of the delicate integument. I
have sometimes perceived what seemed to be
a sacculated or spiral intestine ; and, as eva-
poration proceeds, this has apparently been
surrounded by minute tortuous tubes ; but the
fallacy of the latter appearance is easily de-
tected. A structure, which I have found in
more recent and better preserved specimens
than those which were the subjects of my first
description, is evidently real, and may pro-
bably belong to the generative system of the
Trichina ; it consists of a small rounded cluster
of granules of a darker or more opaque nature
than the rest of the body ; it is situated about
one-fifth of the length of the animal from the
larger or anterior extremity, and extends about
half-way across the body.

ENTOZOA.

115

Dr. Arthur Farre, whose powers of patient
and minute observation and practised skill
with the microscope, are well known to those
who have the pleasure of his acquaintance,
discovered, by theexamination of recent Trichinae
under favourable circumstances, that they pos-
sess an intestinal canal with distinct parietes.
He describes it as commencing at the large end
of the worm, bounded by two parallel but
slightly irregular lines for about one-fifth of
the length of the body, and then assuming a
sacculated structure which " becomes gradually
lost towards the smaller end where the canal
assumes a zig-zag or perhaps spiral course, and
at length terminates at the small end."*

In a recent examination of some Trichina
from an aged male subject at St. Bartholomew's
Hospital, I perceived a transverse slit close to
the small extremity on the concave side, which
I regard as the anus.

The muscles which are affected by the Tri-
china are those of the voluntary class ; and the
superficial ones are found to contain them in
greater numbers than those which are deep-
seated; the pectoralis major, latissimus dorsi,
and other large flat muscles usually present
them in great abundance. They have been
detected in the muscles of the eye, and even
in those belonging to the ossicles of the ear,
and of whose actions we are wholly uncon-
scious: they also occur in the diaphragm, in
the muscles of the tongue, in those of the
soft palate, in the constrictors of the pharynx,
in the levator ani, in the external sphincter ani,
and in the muscles of the urethra. But they
have not yet been detected in the muscular
tunic of the stomach and intestines-, in the
detrusor urinae, or in the heart. It is an inte-
resting fact that all the muscles infested by the
Trichina are characterized by the striated ap-
pearance of the ultimate fasciculi : while the
muscles of organic life, in which they are
absent, have, with the exception of the heart,
smooth fibres, not grouped into fasciculi, but
rcticularly united.

From the instances of this parasitical affec-
tion of the human body which have already
been recorded, and from other unpublished
cases in which I have examined the worms,
it is evident that their presence in the system
is unconnected with age, sex, or any particular
form of disease. They have been found in the
bodies of persons who have died of cancer of
the penis ; tubercles in the lungs ; exhaustion
of the vital powers by extensive external ul-
ceration of the leg ; fever combined with tu-
bercles in the lungs; aneurism of the aorta;
sudden depression of the vital powers after a
comminuted fracture of the humerus ; diar-
rhea.

The cases which had occurred before the
publication of the first description of this
Entozoon led me to conceive that, although the
species was of so minute a size, yet the num-
ber of individuals infesting the body was so
immense, and their distribution through the
muscular system so extensive, that they might

* See Medical Gazette, December, 1835.

occasion debility from the quantity of nutri-
ment required for their support; and I ob-
served " that it was satisfactory to believe, that
the Trichina are productive of no other con-
sequences than debility of the muscular system;
and it may be questioned how far they can be
considered as a primary cause of debility, since
an enfeebled state of the vital powers is the
probable condition under which they are
originally developed. No painful or incon-
venient symptoms were present in any of the
above-mentioned cases to lead the medical
attendants to suspect the condition of the mus-
cular system, which dissection afterwards dis-
closed : and it is probable that in all cases the
patient himself will be unconscious of the
presence of the microscopic parasites which
are enjoying their vitality at his expense."*
Since writing the above, a case has occurred
in which the Trichinae were met with in the
muscles of a man who was killed while in the
apparent enjoyment of robust health by a frac-
ture of the skull. I received portions of the
muscles of the larynx of this individual from
my friend Mr. Curling, Assistant-Surgeon to
the London-Hospital, who has recorded the
case in the Medical Gazette, and the worms
were similar in every respect to those occurring
in the diseased subjects. The deduction there-
fore of the development of the Trichina being
dependent on an enfeeblement of the vital
powers is invalidated by this interesting ex-
ample .f

Leaving now the consideration of Entozoa,
which from their minute size and organization
would have ranked with the vast assemblage
of animalcules which are collected under the
head Infusoria in the Regne Animal, we come
next to the consideration of the animals which
form that scarcely less heterogeneous class, the
Entozoa of Rudolphi. These are distributed by
that Naturalist into five orders, which may be
synthetically arranged and characterized as
follows.

ORDO I. CYSTICA, Rud. (KVO-TH;, vesica.)
Vermes vesiculares, Blasenwiirmer,

Cyst-worms or Hydatids.
Char. Body flattened or rounded, conti-
nued posteriorly into a cyst, which is
sometimes common to many indivi-
duals. Head provided with pits (bo-
thria two or four) or suctorious pores
(four), and with a circle of booklets
or with four unarmed or uncinated
tentacles. No discernible organs of
generation.

06s. This order is not a very natural one ;
the species composing it are closely allied to the
Tape-worms in the structure of the head, and
when this is combined with a jointed structure
of the body, as in the Cysticercus fasciolaris
common in the liver of Rats, the small caudal
vesicle forms but a slight ground for a distinc-
tion of ordinal importance. The Cystica of
Rudolphi form part of the Order Tanioidea of
Cuvier ; and may be regarded as representing

* Zoological Transactions, vol. i. p. 315.
t Zool. Trans, vol. i. p. 323.

i 2

116

ENTOZOA.

the immature states of the higher orders of
Sterelmintha.

ORDO II. CESTOIDEA, (xecrro?, cingulum,
»&}$, forma.)

Vermes taniaformes, Bandwurmer,

Tape-worms.

Char. Body elongated, flattened, soft;
continuous, or articulated. Head either
simply labiate, or provided with pits
(bothria) or suctorious orifices (oscula
suctoria) either two or four in number,
and sometimes with four retractile un-
armed or uncinated tentacles. Andro-
gynous generative organs.
Obs. In this order Rudolphi includes the
inarticulated Ligula, with simple heads un-
provided with bothria or suckers; a conjunc-
tion which detracts from the natural character
of the group. Cuvier separates the Ligula
from the T<eni<e, and they form exclusively his
Order Cestoidea ; it must be observed, however,
that the passage from the one to the other is
rendered very gradual by the traces of bothria,
and of generative organs which appear in the
higher organized Lignite found in the intestines
of Birds ; and respecting which Rudolphi
hazards the theory that they are the more simple
Lignite of Fishes, developed into a higher grade
of structure by the warmth and abundant nutri-
ment which they meet with in the intestines of
Birds which have swallowed the Fishes infested
•by them.

ORDO III. TREMATODA, (r§*jf*a, foramen,
TgJj/xaTflj&j? foraminosus.)

Vermes s-uctorii, Saugw'nrmer, Fluke-
worms.

Char. Body soft, rounded, or flattened.
Head indistinct, with a suctorious fo-
ramen ; generally one or more suctorious
cavities for adhesion in different parts of
the body. Organs of both sexes in each
individual.

Obs. This very natural order includes, in the
system of Cuvier, many species which do not
infest other animals, but are found only in
fresh waters ; these non-parasitic species form
the greater part of the genus Planaria of Muller,
(fig. 80.) Rudolphi, who seems to have sup-
posed the Planaria to be of a more simple
organization than they truly possess, approxi-
mates them to the Ligulae or inarticulated Ces-
toidea. Other naturalists, unwilling to asso-
ciate the Planaria with the Entozoa, have
placed them in the Class Anellida, but the
absence of a ganglionic abdominal nervous
chord, of a floating intestine, and of an anus,
renders such an association very arbitrary.
ORDO IV. ACANTHOCEPHALA, (axavfla,
spina, tttQctteit caput.)

Vermes uncinati, Hacken-w'rirmer,

Hooked-worms.

Char. Body elongated, round, sub-elas-
tic. Head with a retractile proboscis
armed with recurved spines, (jig- 74.)
Sexual Organs appropriated to distinct
individuals, male and female.
Obs. This natural group includes the most
noxious of the internal parasites ; fortunately
no species is known to infest the human body.

They abound in the lower animals, and present
great diversity of form, some being cylindrical
and others sacciform.

ORDO¥. NEMATOIDEA, (ynf.tx>,filu™> «^°?>
forma.)

Vermes teretes, Rund-w'urmer. Round-
worms.

Char. Body elongated, rounded, elastic.
Mouth variously organized according to
the genera. A true intestinal canal
terminating by a distinct anus. Sexes
distinct.

06s. The internal character which Rudolphi
has introduced in his definition of this Order,*
viz. that derived from the structure of the ali-
mentary canal, its free course through the body,
and its termination by a distinct anus at the
extremity opposite the mouth, is one of much
greater value than any of the external modifica-
tions of the body which characterize the four
preceding orders. It is, in fact, a trait of or-
ganization which is accompanied by corre-
sponding modifications of other important
parts, more especially the nervous system.

The Entozoa which manifest this higher type
of structure form in the syslem of Cuvier a
group equivalent to that which is constituted
by the four other orders combined. The En-
tozoa composing the first four orders above
characterized have no distinct abdominal cavity
or intestine, but the digestive function is carried
on in canals without an anal outlet excavated
in the parenchymatous substance of the body,
and Cuvier accordingly denominates them the
Vers intestinaux parenchymateux. The Ne-
matoidea, with which Cuvier rightly associates
the genus Pentastoma of Rudolphi, and also
(but less naturally) the Vers rigidules of La-
marck, or Epizoa, he denominates ' Vers intes-
tinaux cavitaires.f

With respect to the Epizoa, or the external
Lernaean parasites of Fishes, although they
agree with the Nematoidea and all inferior
Entozoa in the absence of distinct respiratory
organs, yet the ciliated natatory members which
they possess in the young state, and the exter-
nal ovarian appendages of the adult, are cha-
racters which raise them above the Entozoa as
a distinct and higher class of animals, having
intimate relations with the soft-skinned Sipho-
nostomous Crustaceans.

Limiting, then, the Cavitary Entozoa to the
Nematoidea of Rudolphi, and the Genera Lin-
guatula, Pentastoma, Porocephalus, and Syn-
gamus, which, under the habit of Cestoid or
Trematode Worms, mask a higher grade of
organization, we propose to regard them as a
group equivalent to the Sterelmintha, and to
retain for them the name of Ccdelmintha.

The class of Entozoa thus constituted em-
braces already the types of three different
orders, of which one is formed by the Nema-
toidea of Rudolphi, a second has been esta-
blished by Diesmg for the genus Pentastoma
and its congeneric forms, under the name of

* " Corpus teres elasticum, tractus intestinalis
hinc ore, illinc ano ternainatus. Alia individua
mascula, alia femiuea."— Synops. Entos. p. 3.

ENTOZOA.

117

Acanthotheca ; and the singular organization
of the Syngamtu of Siebold, presently to be
described, clearly indicates the type of a third
order of Cavitary Entozoa.

As a short description has already been
given of the species of Protelmintha which
inhabit the human body, we shall proceed to
notice those species belonging to the two di-
visions of Entozoa above defined, which have
a similar locality, before entering upon the
organization of the class generally.

The first and simplest parasite which de-
mands our attention is the common globular
Hydatid, which is frequently developed in the
substance of the liver, kidney, or other abdo-
minal viscera, and occasionally exists in prodi-
gious numbers in dropsical cysts in the human
subject.

Considerable diversity of opinion still exists
as to the nature of these ambiguous productions,
to which Laennec first gave the name of Ace-
phalocysts ; we shall nevertheless admit them
into the category of human parasites, for reasons
which are stated in the following descrip-
tion.

The Acephalocyst is an organized being,
consisting of a globular bag, which is com-
posed of condensed albuminous matter, of a
laminated texture, and contains a limpid co-
lourless fluid, with a little albuminous and a
greater proportion of gelatinous substance.

The properties by which we recognize the
Acephalocyst as an independent or individual
organized being are, first, growth, by intrinsic
power of imbibition ; and, secondly, reproduc-
tion of its species by gemmation." The young
Acephalocysts are developed between the layers
of the parent cyst, and thrown off either inter-
nally or externally according to the species.

As the best observers agree in stating that
the Acephalocyst is impassive under the appli-
cation of stimuli of any kind, and manifests
no contractile power either partial or general,
save such as evidently results from elasticity,
in short, neither feels nor moves, it cannot, as
the animal kingdom is at present characterized,
be referred to that division of organic nature.

It would then be a question how far its
chemical composition forbids us to rank the
Acephalocyst among vegetables. In this king-
dom it would obviously take place next those
simple and minute vesicles, which, in the
aggregate, constitute the green matter of
Priestly, (Protococcus viridis, Agardh;) or
those equally simple but differently coloured
Psychodiariee, wrn'ch give rise to the red
snow of the Arctic regions, (Protococcus Ker-
mesianus.) These " first-born of Flora" con-
sist in fact of a simple transparent cyst, and
propagate their kind by gemmules developed
from the external surface of the parent.

Or shall we, from the accidental circum-
stance of the Acephalocyst being developed
in the interior of animal bodies, regard it, as
Rudolphi would persuade, in the same light
as an ulcer, or pustule, — as a mere morbid pro-
duct?

The reasons assigned by the learned Pro-

Fig. 56.

fessor* do induce us to consider the Acephalo-
cyst as a being far inferior in the scale of orga-
nization to the Cysticercus; but still not the less
as an independent organized species, sharing its
place of development and sphere of existence
in common with the rest of the Entozoa.

Acephalocyst is endogena. Pill-box Hydatid
of Hunter, (Jig. 56). This species is so called
from the circum-
stance of the gem-
mules being detach-
ed from the internal
surface of the cyst,
where they grow,
and, in like man-
ner, propagate their
kind, so that the
successive genera-
tions produce the
appearance descri-
bed by Hunter and
other pathologists.
The membrane

Acephalocystis endogena.

of the cyst is thin, delicate, transparent, or
with a certain pearly semi-opacity; it tears
readily and equally in every direction, and
can, in large specimens, be separated into
laminae. The phenomenon of endosmose is
readily seen by placing the recent Acepha-
locyst in a coloured liquid, little streams of
which are gradually transmitted and mingle
with the fluid of the parasite. The vesicles or
gemmules, developed in the parietes of the
cyst, may be observed of different sizes, some
of microscopic dimensions, others of a line in
diameter before they are cast off, see fig. 56,
where a shows the laminated membrane, b the
minute Acephalocysts developed between its
layers.

The Acephalocyst of the Ox and other Ru-
minant Animals differs from that of the Hu-
man Subject in excluding the gemmule from the
external surface, whence the species is termed
Acephalocystis exogena by Kuhl. Both kinds
are contained in an adventitious cyst, com-
posed of the condensed cellular substance of
the organ in which they are developed.

The Genus Echinococcus is admitted by
Rudolphi into the Order Cystica, less on ac-
count of the external globular cyst, which,
like the Acephalocyst, is unprovided with a
head or mouth, than from the structure
of the minute bodies which it contains,
and which are described as possessing the
armed and suctorious head characteristic of
the Ccenuri and Cysticerci. It must be ob-
served that Rudolphi-f does not ascribe this

* Mihi, quidem, ea tandem hydatis animal
vivum vocatur, quae vitam propriam degit uti Cys-
ticerci, Coenuri, &c. Quae autem organismi alieni
(v. c. humani) particulum efficit animal, me
judice, dici nequit. Mortua non est, quamdiu
organismi partem sistit, uti etiam ulcus, pustula,
effiorescentia ; sed haec ideo non sunt animalia. —
Synops. Entoz. p. 551.

t Vermiculi globosi, subglobosi, obovati, obcor-
dati, etc.; pro capite plus minus vel exserto vel
retracto ; postice mox obtusissimi, mox obtusi, mox
acuti. Corona uncinulorum, uti videtur, duplex.

118

ENTOZOA.

Fig. 57.

complicated structure to the vermiculi of the
Human Echinococcus on his own authority,
and speaks doubtfully respecting the coronet
of hooklets and suctorious mouths of the ver-
miculi contained in the cyst of the Echinococcus
of the Sheep, Hog, &c.

The Echinococcus hominis, (fig. 57,) which
occurs in cysts in the
liver, spleen, omen-
turn, or mesentery, is
composed of an exter-
nal yellow coriace-
ous, sometimes crus-
taceous tunic, and an
internal transparent,
firm, gelatinous
membrane. The form
of the contained ver-

Echinococcus homini*. miculi is represented
in the magnified view

subjoined, (jig. 58,) taken from the Elminto-
grafia humana of Delle Chiaje.

Fig. 58.

Vermiculi of Echinococcus hominis, highly magnified.

Miiller* has recently described a species of
Echinococcus voided with the urine by a young
man labouring under symptoms of renal disease.
The tunic of the containing cyst was a thick
white membrane, not naturally divided into
laminae; the animalcules floating in the con-
tained fluid presented a circle of hooklets and
four obtuse processes round the head ; the pos-
terior end of the body obtuse : some of them
were inclosed in small vesicles floating in the
large one ; others presented a filamentary pro-
cess at their obtuse end, probably a connecting
pedicle which had been broken through.

Of the species entitled Echinococcus veteri-
norum we have carefully examined several in-
dividuals soon after they were extracted from
the recently-killed animal, (a sow, in which
they existed in great abundance in cysts in the
abdomen.) The containing cysts were com-
posed of two layers, artificially separable,
both of a gelatinous texture, nearly colourless
and subtransparent, the external one being the
firmest. The contained fluid was colourless
and limpid, with a few granular bodies floating

Oscula suctoria quatuor ; an hsec in omnibus ? Ipse
saltern in suis Echinococcis non vidi, sed dum Be-
rolini recens examinarem, microscopic solito et
bono destitutus eram. — Hist. Entoz.

* Archiv fur Physiol. (Jahresbericht), L83b\

in it, and immense numbers of extremely mi-
nute particles applied but not adherent to the
internal surface of the cyst. On examining
these particles with a high magnifying power,
they were seen to be living animalcules of an
ovate form, moving freely by means of superfi-
cial vibratile cilia, having an orifice at the smaller
end from which a granular and glairy substance
was occasionally discharged, and a trilobate de-
pression at the greater and anterior extremity
produced by the retraction of part of the body.
I watched attentively and for a long period a
number of these animalcules in the hope of
seeing the head completely protruded, but with-
out success. On compressing the animalculae
between plates of glass, a group of long, slen-
der, straight, sharp-pointed spines became vi-
sible within the body, at its anterior part, and
directed towards the anterior depression, pre-
cisely resembling the parts described and fi-
gured by Ehrenberg as the teeth of the Poly-
gastric Infusories ; the rest of the body was
occupied by large clear globules, the stomachs ?
and smaller granules. Animalcules thus orga-
nized, it is evident, cannot be classed with cystic
Entozoa, but must be referred to the Polygastric
Infusoria.

The globular cyst which is commonly deve-
loped in the brain of Sheep differs from the
Echinococcus in having organically attached to
it a number of small vermiform appendages, pro-
vided severally with suctorious orifices, and an
uncinated rostellum, similar to those in the head
of the Armed Tsenise. But as this cystic genus,
denominated Ccenurus, (xou/o$, communis, ovga,
cauda, from the terminal cyst being common
to many bodies and heads,) is not met with in
the human subject, a simple notice of it is here
sufficient.

When the dilated cyst forms the termina-
tion of a single Entozoon, organized as above
described, it is termed Cysticercus, (x.v<rr^,
vesica, xtpxo?, cauda), and of this genus there
are several species, distinguished for the
most part by the forms and proportions of
the neck or body intervening between the
head and the cyst ; as for example, the Cyst.
Jasciolaris, Cyst, Jistularis, Cyst, longicollis,
Cyst. tenuicollis, &c. The only species of
this genus known to infest the human body
is the Cysticercus cellulose, Rud. (the Hydatis
Finna of Blumenbach). It is developed,
like the Trichina, in the interfascicular cel-
lular tissue of the muscles, and, like it, is in-
variably surrounded by an adventitious cap-
sule of the surrounding substance condensed
by the adhesive inflammation. Fig. 59 exhi-

Fig. 59.

Portion of human muscle, with Cysticercus cdlulosce.

ENTOZOA.

119

bits a portion of muscle thus infested; a the
adventitious cyst laid open, exposing the Hy-
datid ; a' the adventitious cyst elongated by the
extension of the head and neck of the inclosed
hydatid b in the direction of the muscular fibres.
The cysticercus itself sometimes attains the size
exhibited in Jig. 60, in which a indicates the

Fig. 60.

Fig. 61,

Cysticercus
celltdosee.

Magnified head of Cysticerus celluloses.

head, b the neck or body, and c the dilated
vesicular tail. Fig. 61 exhibits the head
sufficiently magnified to show the uncinated
rostellum or proboscis d for irritation and
adhesion, and the suctorious discs e e for im-
bibing the surrounding nutriment.

The occurrence of this Entozoon in the Hu-
man Subject appears to be less common in this
country than on the Continent. In the course
of five years we have become acquainted with
only two cases, one in a subject at the Dis-
secting-Rooms of St. Bartholomew's, the other
in a subject at the Webb-street School of Ana-
tomy. Rudolphi relates that out of two hun-
dred and fifty bodies dissected annually at the
Anatomical School of Berlin, from four to five
were found through nine consecutive years to
be infested more or less copiously with the
Cysticercus cellulose; for the most part the
subjects had been of the leucophlegmatic
temperament, but not affected with ascites or
anasarca. The muscles most obnoxious to
the Entozoon in question are the glutoei, psoas,
iliacus internus, and the extensors of the thigh;
they have been found also in the muscular
tissue of the heart, and in parts not muscular,
as the brain and eye. Soemmering detected
one specimen of the Cysticercus cellulosa
in the anterior chamber of the eye of a young
woman set. 18.* The following is a more re-
cent account of a specimen which was deve-
loped in the anterior chamber of the eye of a
patient in the Glasgow Ophthalmic Infirmary.

" Case. — From the month of August, 1832,
till about the middle of January, 1833, when
she was first brought to Mr. Logan, the child
had suffered repeated attacks of inflammation
in the left eye. Mr. L. found the cornea so
nebulous, and the ophthalmia so severe, that he
dreaded a total loss of sight. He treated the
case as one of scrofulous ophthalmia; and after
the use of alterative medicines, and the appli-
cation of a blister behind the ear, the inflam-

* See Isis, 1830, p. 717, as quoted by Nord-
niann, Mikrographis^he Beitrace zurNatureescLicte
der wirbellosen thiere.

matory symptoms subsided, leaving, however,
a slight opacity of the lower part of the cornea.
After a week, the child was again brought to
Mr. L., who, on examining the eye, disco-
vered, to his great surprise, a semitransparent
body, of about two lines in diameter, floating
unattached in the anterior chamber. This
body appeared almost perfectly spherical, ex-
cept that there proceeded from its lower edge
a slender process, of a white colour, with a
slightly bulbous extremity, not unlike the pro-
boscis of a common fly. This process Mr. L.
observed to be of greater specific gravity than
the spherical or cystic portion, so that it always
turned into the most depending position. He
also remarked that it was projected or elongated
from time to time, and again retracted, so as
to be completely hid within the cystic portion ;
while this, in its turn, assumed various changes
of form, explicable only on the supposition of
the whole constituting a living hydatid.

" On the 3d April, when I examined the case,
I found the cornea slightly nebulous, the eye
free from inflammation and pain, and the ap-
pearances and movements of the animal exactly
such as described by Mr. Logan. When the
patient kept her head at rest, as she sat before
me, in a moderate light, the animal covered
the two lower thirds of the pupil. Watching
it carefully, its cystic portion was seen to be-
come more or less spherical, and then to assume
a flattened form, while its head I saw at one
moment thrust suddenly down to the bottom
of the anterior chamber, and at the next drawn
up so completely as scarcely to be visible. Mr.
Meikle turned *the child's head gently back,
and instantly the hydatid revolved through the
aqueous humour, so that the head fell to the
upper edge of the cornea, now become the
more depending part. On the child again
leaning forwards, it settled like a little balloon
in its former position, preventing the patient
from seeing objects directly before her, or
below the level of the eye, but permitting the
vision of such as were placed above. Mr.
Logan had observed no increase of size in the
animal while it was under his inspection. Mr.
Meikle had watched it carefully for three weeks
without observing any other change than a
slight increase in the opacity of the cystic
portion.

" To every one who had seen or heard of Mr.
Logan's case, the question naturally occurred,
Ought not this animal to be removed from the
eye ? Mr. Logan and Mr. Meikle appeared to
have deferred employing any means for destroy-
ing or removing it ; first, because it seemed to
be producing no mischief: and, secondly, be-
cause there was a probability that it was a
short-lived animal, and likely therefore speedily
to perish and shrink away, so as to give no
greater irritation than a shred of lenticular
capsule. Various means naturally suggested
themselves for killing the animal, such as
passing electric or galvanic shocks through the
eye, rubbing in oil of turpentine round the
orbital region, giving this medicine internally
in small doses, or putting the child on a course
of sulphate of quiua, or some other vegetable

120

ENTOZOA.

bitter known to be inimical to the life of the
Entozoa. As the patient appeared to be in
perfect health, it was natural to suppose that
the other organs were free from hydatids, and
that a change of diet would have little or no
effect upon the solitary individual in the aque-
ous humour. Had she, on the contrary, pre-
sented a cachectic constitution, with pale com-
plexion, tumid belly, debility, and fever, none
of which symptoms were present, we should
have been led to suspect that what was visible
in the eye was but a sample of innumerable
hydatids in the internal parts of the body, and
might have recommended a change of diet,
with some hopes of success. In the course of six
weeks after I saw the patient, the cysticercus
having enlarged in size, the vessels of the con-
junctiva and sclerotica became turgid, the iris
changed in colour, and less free in its motions,
while the child complained much of pain in the
eye ; it was decided that the operation of ex-
traction should be attempted, and I owe to
Dr. Robertson of Edinburgh, who operated, the
communication of the following particulars.
The incision of the cornea was performed with-
out the slightest difficulty, but no persuasion
or threats could induce the child again to open
the eye ; she became perfectly unruly, and the
muscles compressed the eye-ball so powerfully
that the lens was forced out, and the hydatid
ruptured. The patient was put to bed in this
state. In the evening Dr. R. succeeded in
getting the girl to open the eyelids, when with
the forceps he extracted from the lips of the
incision the remains of the animal in shreds,
it being so delicate as scarcely to bear the
slightest touch. A portion of the iris remained
in the wound, which nothing would induce the
girl to allow Dr. R. to attempt to return.

" After the eye healed, the cornea remained
clear, except at the cicatrice, where it was only
semitransparent; the pupil, in consequence of
adhesion to the cicatrice, was elliptical, and the
opaque capsule of the lens occupied the pu-
pillary aperture. The patient readily recog-
nized the presence of light."

The Cysticercus cellulose occurs also in
quadrupeds, and is found most commonly and
in greatest abundance in the Hog, giving rise
to that state of the muscles which is called
" measly pork."

Of the Cestoid Cider of Entozoa two species
belonging to different genera infest the Hu-
man Body. The Swiss and Russians are
troubled with the Bothriocephalus latus ; the
English, Dutch, and Germans with the Ttenta
solium: both kinds occur, but not simulta-
neously in the same individual, in the French.
It is not in our province to dwell upon the
medical remedies for these parasites, but we
may observe that the old vermifuge mentioned
by Celsus, viz. the bark of the pomegranate, is
equally efficacious and safer perhaps than the
oleum terebinthina commonly employed in
this country for the expulsion of the Tape-worm.
From the singular geographical distribution,
as it may be termed, of the above Cestoid
parasites, the Bothriocephalus latus rarely falls
under the observation of the English Entozoo-

Fig. 62.

legist. It may be readily distinguished from
the Tania solium by the form of the segments,
which are broader than they are long, and by
the position of the genital pores, which occur
in a series along the middle of one of the flat-
tened surfaces of the body, and not at the mar-
gin of each segment as in the Tania solium.
The head, which was for a long time a deside-
ratum in natural history, has at length been dis-
covered by Bremser. It is of an elongated form,
two-thirds of a line in length, and presents, in-
stead of the four round oscula
characteristic of the true Tania,
two lateral longitudinal fossa,
or bothria, (a a,^g.62, which
is a highly-magnified view of
the head of the Bothrioce-
phalus latus.)

The Tania solium (Jig. 63)
attains the length of from four
to ten feet, and has been ob-
served to extend from the pylo-
rus to within seven inches of
the anus of the human intes-
tine.* Its breadth varies from
one-fourth of a line at its an-
terior part to three or four
lines towards the posterior part
of the body, which then again
diminishes. The head is small,
and generally hemispherical,
broader than long, and often
as if truncated anteriorly : the

Fig 63.

Head of Bothrio-
ceplialus latus
magnified.

Tcenia solium, two-thirds natural size.

* See Robin, in Jjurnal dc Medecine, torn. xxv.
(1766), p. 222.

ENTOZOA.

121

four mouths, or oscula, are situated on the
anterior surface, (a, Jig. 63,) and surround
the central rostellum, which is very short, termi-
nated by a minute apical papilla, and surround-
ed by a double circle of small recurved hooks.
The segments of the neck, or anterior part of the
body, are represented by transverse rugae, the
marginal angles of which scarcely project be-
yond the lateral line; the succeeding seg-
ments are subquadrate, their length scarcely
exceeding their breadth, they then become sen-
sibly longer, narrower anteriorly, thicker and
broader at the posterior margin, which slightly
overlaps the succeeding joint ; the last series of
segments are sometimes twice or three times as
long as they are broad. The generative orifices
(b, 6) are placed near the middle of one of the
margins of each joint, and are generally alter-
nate.

The T&nia solium is subject to many varieties
of form or malformations; the head has been ob-
served to present six oscula instead of four. In
the Imperial Museum at Vienna, so celebrated
for its entozoological collection, there is a por-
tion of a T<enia solium, of which one of the
margins is single and the other double, as it
were two taeniae joined by one margin. In the
Museum of the College of Surgeons is preserved
a fragment of the Taenia solium of unusual size;
it swells out suddenly to the breadth of three-
fourths of an inch with a proportionate degree
of thickness, and then diminishes to the usual
breadth.*

The species of Taenia infesting the intestines
of other animals are extremely numerous, ne-
vertheless they are rare in Fishes, in which they
seem to be replaced by the Eothriocephali and
Ligula. The determination oLthe species in
this, as in every other natural ana circumscribed
genus, is extremely difficult and often uncer-
tain : their study is facilitated by distributing
them into the three following sections, of which
the first includes those species which are de-
prived of a proboscis, T<eni<£ inermes ; the
second those which have a proboscis, but un-
armed, T&nia rostellata; the

Fig. 64. third the Tape-worms with an
uncinated proboscis, T <eni<e ar-

Distoma hepa-
ticum, twice
natural size.

same locality. The form of this species of En-
tozoa is ovate, elongate, flattened ; the anterior
pore or true mouth (a) is round and small, the
posterior cavity (6), which is imperforate and
subservient only to adhesion and locomotion,
is large, transversely oval, and situated on the
ventral surface of the body in the anterior
moiety. Between these cavities there is a third
orifice (c) exclusively destined, like the orifice
on each joint of the Taenia, to the generative
system; and from which a small cylindrical
process, or lemniscus, is generally protruded in
the full-sized specimens.

The form of the body is so different in the
young Distomata, that Rudolphi was induced
to believe the specimens from the human gall-
bladder which were in this state, to belong to
a distinct species, which he termed lanceo-
latum ; this modification, which is wholly de-
pendent upon age, is shown in the subjoined
figure; and we shall hereafter have to notice the
more extraordinary changes, amounting to a
metamorphosis, which the Distomata infesting
the intestines of Fish undergo.

The Polystoma Pinguicola was discovered
by Treutler, in the cavity of an indurated adi-
pose tubercle, in the left ovarium of a female,
aetat. 20 ; it is represented in situ, at A,/g. 62.
Its natural size and shape
is shewn at B, the body is
depressed,subconvexabove,
concave below, subtruncate
anteriorly, a little contracted
behind the head, pointed at
the posterior extremity. On
the under side of the head
C, there are six orbicular
pores disposed in a semi-
lunar form : a larger sucto-
rious cavity occurs on the
ventral aspect at the begin-
ning of the tail (b B), and a
small orifice is situated at
the apical extremity.

A second species of Po-
lystoma (Polystoma Vena-
rum), stated by Treutler to
have been situated in the
anterior tibial vein of a Man,

The Trematode Order, which
is the most extensive division of
the Parenchymatous class of En-
tozoa, and embraces the greatest
number of generic forms, in-
cludes only two species infesting
the human body, one of which,
the liver-fluke (Distoma hepati-
cum), is extremely rare, and the
other (Polystoma Pinguicola)
somewhat problematical.

The Distoma hepaticum (Jig.
64) is found in the gall-bladder
and ducts of the liver of a variety
of quadrupeds, and very com-
monly in the Sheep. When it
occurs in the Human species, it
is generally developed in the

Polystoma
Pinguicola.

* See Catal. of Nat. Hist. No. 216.

which was accidentally ruptured while bathing,
is generally supposed to have belonged to a
species of Planaria, and to have been acci-
dentally introduced into the strange locality
above-mentioned.

The worms of the Trematode order are those
which are most frequent in the interior of the
eyes of different animals, perhaps the most
singular situation in which Entozoa have as yet
been found, and respecting which much in-
teresting information has recently been given
by Dr. Nordmann, in the first part of his
beautiful work entitled " Mikrographische
Beitrage zur Naturgeschicte der Wirbellosen
Thiere." Of the species described and figured
in that work, we have selected for illustration
the Diplostomurn volvens.

Fig. 66 exhibits a magnified view of the
vitreous humour of a Perch ( Percafluviatilis,
Linn.) containing numerous specimens of this

122

ENTOZOA.

Fig. 66.

Fig. 67.

Diplostomum volvens in the eye of a Perch.

parasite, which sometimes exists in such pro-
digious numbers, that the cavity of the eyeball
is almost exclusively filled by them. They
not only infest the vitreous but also the aqueous
humours, and have been found in the choroid
gland.

All the species of Diplostomum are very
small, seldom exceeding a sixth part of a line
in length. They resemble the genus Distoma,
and present some affinity to" the Cercaria,
which infest the fresh-water Snails ; but they
have characters peculiar to themselves which
entitle them to rank as a distinct genus ; of
these the principal external one is the addi-
tional sucker developed on the ventral aspect
of the body, as compared with Distoma,
whence Nordmann calls the genus Diplosto-
mum, though Diplo-cotylus would be the more
appropriate designation, since, as before ob-
served, the ventral depressions are simply
organs of adhesion, and have no communication
with the alimentary canal. Besides the suckers
the Diplostomum has an anterior mouth (a, jig.
81), as in the Distoma. The first or anterior
sucker (b,Jlg. 81 ) is twice the size of the mouth;
and the second (c,jig.Ql) is again double the
size of the former. As the figure shows the
vessels from the dorsal aspect, these suckers
can only be seen in outline. The animal has
great power over them and can contract the
parenchyma of the body surrounding them,
so as to make them project like rudimental
extremities from the ventral surface.

It has been already observed that no species
of the Acanthocephalous order of Entozoa has
hitherto been found in the Human body, the
illustration of this form of the Sterelmintha
will therefore be confined to the section treat-
ing of the general anatomy of the Entozoa.

The Class Calelmintha contains several
species of Entozoa which are obnoxious to
man; of these may be first mentioned the
Medina or Guinea-worm (Filaria Medinensis,
Gmel.) This species is developed in the sub-
cutaneous cellular texture, generally in the
lower extremities, especially the feet, sometimes
in the scrotum, and also, but very rarely, be-

neath the tunica conjunctiva
of the eye. It appears to be
endemic in the tropical regions
of Asia and Africa.

The length of this worm
varies from six inches, to two,
eight, or twelve feet; its thick-
ness from half to two-thirds
of a line; it is of a whitish
colour in general, but some-
times of a dark brown hue.
The body is round and sub-
equal, a little attenuated to-
wards the anterior extremity.
In a recent specimen of small
size, we have observed that the
orbicular mouth was surround-
ed by three slightly raised
swellings, which were conti-
nued a little way along the
body and gradually lost ; the
body is traversed by two lon-
gitudinal lines corresponding
to the intervals of the two well-
marked fasciculi of longitu-
dinal muscular fibres. The
caudal extremity of the male
is obtuse, and emits a single
spiculum; in the female it is
acute and suddenly inflected.

The Filaria Medinensis, as
has just been observed, is oc-
casionally located in the close
vicinity of the organ of vision ;
but another much smaller spe-
cies of the same Genus of
Nematoidea infests the cavity
of the eyeball itself.

The Filaria oculi humani
was detected by Nordmann in
the Liquor Morgagni of the
capsule of a crystalline lens of
a man who had undergone the
operation of extraction for ca-
taract under the hands of the
Baron von Grafe. In this in-
stance the capsule of the lens
had been extracted entire, and
upon a careful examination
half an hour after extraction
there were observed in the fluid
above-mentioned two minute
and delicate Filaria coiled up
in the form of a ring. One of
°

microscopically, presented a rupture in the mid-
dle of its body, probably occasioned by the ex-
tracting needle, from which rupture the intesti-
nal canal was protruding ; the other was entire
and measured three-fourths of a line in length ;
it presented a simple mouth without any appa-
rent papillae, (as are observed to characterize
the large Filaria which infests the eye of the
Horse,) and through the transparent integument
could be seen a straight intestinal canal, sur-
rounded by convolutions of the oviducts, and
terminating at an incurved anal extremity.

The third species of Filaria enumerated
among the Entozoa Hominis is the Filaria

ENTOZOA.

123

Filaria bronchialis,
magnified.

bronchialis (fig. 68); it was detected by Treut-
ler* in the enlarged
Fig. 68. bronchial glands of a

man : the length of this
worm is about an inch ;
it is slender, subatten-
uated anteriorly (a),
and emitting the male
spiculum from an in-
curved obtuse anal ex-
tremity (b).

The next Human
Entozoon of the No-
rn atoid order belongs
to the genus Tricfto-
cephalus, which, like
Filaria, is character-
ized by an orbicular
mouth, but differs from
it in the capillary form
of the anterior part of
the body, and in the
form of the sheath or
preputial covering of
the male spiculum. The species in question,
the Tricocephalus dispar, Rud. is of small size,
and the male (* fig. 69) is rather less than the
female. It occurs most commonly in the
ccecum and colon, more rarely in the small
intestines. Occasionally it is found loose in
the abdominal cavity, having perforated the
coats of the intestine. The capillary portion
of this species makes about two-thirds of its
entire length ; it is transversely striated, and
contains a simple straight intestinal canal;
the head (a) is acute, with a small simple
terminal mouth. The thick part of the body
is spirally convoluted on the same plane, and
exhibits more plainly the dilated moniliform
intestine (6) ; it terminates in an obtuse anal
extremity, from the inner side of which pro-
ject the intromittent spiculum and its sheath
(c, d). The corresponding extremity in the
female exhibits a simple foramen, which, like
the outlet of a cloaca, serves the office of both
anus and vulva.

With respect to the following parasite of the
Human body, the Spiroptera Hominis, Rud.,
considerable obscurity prevails. A poor wo-
man, who is still living in the workhouse of
the parish of St. Sepulchre, London, has been
subject, since the year 1806, (when she was
twenty-four years old,) up to the present time,
to retention of urine, accompanied with dis-
tress and pain indicative of disease of the
bladder. The catheter has been employed
from time to time during this long period to
draw off the urine, and its application has
been, and continues occasionally to be, followed
by the extraction and subsequent discharge of
worms, or vermiform substances, with nume-
rous small granular bodies. The latter are of
uniform size, resembling small grains of sand :
those which we have examined, and which were
preserved in spirit, present a subglobular, or
irregularly flattened form ; but when recently

* Opusc. Patholog. Anat. p. 10, tab. ii. fig. 3—
7. Hamularia Lymphatica.

Fig 69.

Trichocephalw dispar. (* Natural sixe.)

expelled, I am assured by my friend Dr.
Arthur Farre, that they are perfectly spherical ;
they consist of an external smooth, firm, dia-
phanous coat, including a compact mass of
brown and minutely granular substance. The
inner surface of the containing capsule pre-
sents, under the microscope, a regular, beau-
tiful, and minute reticulation, produced by
depressions or cells of a hexagonal form.
These, therefore, we regard as ova, and not as
fortuitous morbid productions.* The vermi-

* " Ovula vero sic dicta subglobosa cum arenulis

124

ENTOZOA.

form substances are elongated bodies of a
moderately firm, solid, homogeneous texture,
varying in length from four to eight inches ;
attenuated at both extremities; having the
diameter of a line half-way between the ex-
tremities and the middle part, where the body
is contracted and abruptly bent upon itself.
Some are irregularly trigonal, others tetragonal.
In the three-sided specimens one surface is
broad, convex, and smooth ; the other two are
narrow and concave, and separated by a nar-
row longitudinal groove, in which is sometimes
lodged a filamentary brown concretion. In
the tetragonal portions the broad smooth sur-
face is divided into two parts by the rising of
the middle part of the convexity into an angle.
The most remarkable appearance in these am-
biguous productions is the beautiful crenation
of one of the angles or ridges between the
convex and concave facet; which, from its
regularity and constancy, can hardly be ac-
counted for on the theory of their nature and
origin suggested by Rudolphi : * lymphamque
in canalibus fistulosis coactam passimque com-
pressam filum inaequale efformare crediderim.'*
On the other hand it is equally difficult to form
any satisfactory notion of these substances
as organized bodies growing by an inherent
and independent vitality. We have not been
able to observe a single example in which the
substance had both extremities well defined
and unbroken; these, on the contrary, are
flattened, membranous, and more or less jagged
and irregular. They present no trace of ali-
mentary or generative orifices on any part of
their exterior surface, nor any canals subser-
vient to those functions, in the interior paren-

Fig. 70.

Spiroptera honunis. (* Natural sixe.)

per catheterem ex vesica pauperculae educta, ne-
quaquam talia habenda sunt. Corpuscula sunt
plus minus globosa, tertiam lineae partem diametro
superantia, duriuscula, forcipi comprimenti reni-
tentia, dissecta solida visa, quominuspro hydatulis
haberi possint, quales primo suspicatus sum. Con-
crementae sunt lymphatica in vesica imorbosa ex
humoribus alionatis ibidem secretis, simili forsan
modo acarenulae ex lolio praecipitata." — Rudolphi,
Syiiops. Entoz. p. 251.
* Ibid. p. 252.

chyma. If subsequent observations on re-
cently expelled specimens of these most
curious and interesting productions should,
however, establish their claims to be regarded
as Entozoa, they will probably rank as a sim-
ple form of Sterelmintha*

The existence of the Spiroptera Hominis is
founded on the observation of substances very
different from the preceding productions. The
specimens so called were transmitted to Ru-
dolphi, in a separate phial, at the same time
with the ova and larger parenchymatous bodies
above described, and are presumed to have
been expelled from the same female under the
same circumstances. They consisted of six
small Nematoid worms of different sexes;
the males (Jig. 70*) were eight, the females ten
lines in length, slender, white, highly elastic.

The head (a, jig. 70) truncated, and with
one or two papillae ; the mouth orbicular, the
body attenuated at both extremities, but espe-
cially anteriorly. The tail in the female
thicker, and with a short obtuse apex ; that of
the male more slender, and emitting a small
mesial tubulus (c), probably the sheath of the
penis: a dermal aliform production near the
same extremity determines the reference of this
Entozoon to the genus Spiroptera.

There are no specimens of this Entozoon
among the substances discharged from the
urethra of the female, whose case is above
alluded to, which are preserved in the Museum
of the College of Surgeons.

The following parasite of the urinary appa-
ratus, concerning which no obscurity or doubt
prevails, is the Strongylm gigas (fig- 71), the
giant not only of its genus but of the whole
class of cavitary worms. This species is de-
veloped in the parenchyma of the kidney
itself, and occasionally attains the length of
three feet, with a diameter of half an inch.
A worm of nearly this magnitude, which oc-
cupied the entire capsule of the left kidney,
of the parenchyma of which it had occasioned
the total destruction, is preserved in the collec-
tion of the Royal College of Surgeons.

The male Slrongylus gigas is less than the
female, and is slightly attenuated at both ex-
tremities. The head («) is obtuse, the mouth
orbicular, and surrounded by six hemispherical
papillae (A); the body is slightly impressed
with circular striae, and with two longitudinal
impressions ; the tail is incurved in the male,
and terminated by a dilated pouch orbursa, from
the base of which the single intromittent spi-
culum (6) projects. In the female the caudal
extremity is less attenuated and straighter,
with the anus (c) a little below the apex : the
vulva (d,fg. 95) is situated at a short distance
from the anterior extremity.

The Strongylm gigas is not confined to the
Human Subject, but more frequently infests
the kidney of the Dog, Wolf, Otter, Raccoon,
Glutton, Horse, and Bull. It is generally of
a dark blood-colour, which seems to be owing

* These bodies are figured in the excellent ac-
count of the present anomalous case by Mr. Law-
rence, in the Medico - Chirurgical Transactions,
vol. ii. pi. 8, p. 385.

ENTOZOA.

125

St rongylus gigcu, male.

to the nature of its food, which is derived from
the vessels of the kidney, as, where suppuration
has taken place around it, the worm has been
found of a whitish hue.

The Round-worm (Ascaris Lwnbricoides,
Linn.) (Jig. 72) is the first described* and
most common of the Human Entozoa, and
is that which has been subjected to the most
repeated, minute, and successful anatomical
examinations. It is found in the intestines of
Man, the Hog, and the Ox. In the Human
subject the round worms are much more com-
mon in children than in adults, and are ex-
tremely rare in aged persons. They are most
obnoxious to individuals of the lymphatic tem-
perament, and such as use gross and indi-
gestible food, or who inhabit low and damp

* It is the ix/xivc <rrfoyyv\ot of Hippocrates.

.Fig. 72. localities. They generally occur
te in the small intestines.

The body is round, elastic, with
a smooth shining surface, of a
whitish or yellowish colour ; atte-
nuated towards both extremities,
but chiefly towards the anterior
one (a, Jig. 72), which commences
abruptly by three tubercles which
surround the mouth, and charac-
terize the genus. The posterior
extremity (6) terminates in an ob-
tuse point, at the apex of which a
small black point may frequently
be observed. In the female this
extremity is straighter and thicker
than in the male, in which it is
terminated more acutely, and is
abruptly curved towards the ventral
side of the body. The anus is
situated in both sexes close to the
extremity of the tail, in form like
a transverse fissure. In the female
the body generally presents a con-
striction at the junction of the an-
terior with the middle third (c) in
which the vulva (c?) is situated.

The body of the Ascaris lumbri-
coides is transversely furrowed with
numerous very fine striae, and is
marked with four longitudinal equi-
distant lines extending from the
head to the tail. These lines are
independent of the exterior enve-
lope, which simply covers them;
two are lateral, and are larger than
the others, which are dorsal and
ventral. The lateral lines com-
mence on each side the mouth,
but, from their extreme fineness,
can with difficulty be perceived;
they slightly enlarge as they pass
downwards to about one-third of
a line in diameter in large speci-
mens, and then gradually diminish
to the sides of the caudal extremi-
ty. They are occasionally of a red
colour, and denote the situation of
the principal vessels of the body.
The dorsal and abdominal longitu-
dinal lines (e, fig. 72) are less
marked than the preceding, and
by no means widen in the same
proportion at the middle of the
body. They correspond to the two
nervous chords, hereafter to be
described.

The last species of Human En-
tozoon which remains to be noticed
is the Ascaris vermicularis (fig. 73),
a small worm, also noticed by Hip-
pocrates under the name of acrxa^?,
and claiming the attention of all phy-
sicians since his time, as one of the
most troublesome parasites of chil-

lumb^i^ides dren> and occasionally of adults ;
in both of whom it infests the larger

intestines, especially the rectum.

The size of the Ascaris vermicularis varies

126

ENTOZOA.

Atcarisver-

according to the sex ; the males rarely equal
two lines in length ; the females attain to five
lines (*fig. 73.) They are proportionally slen-
der, white, and highly elastic. The
Fig. 73. head is obtuse, and presents, ac-
\tt cording to the repeated observa-
tions of the experienced Rudolphi,

- the three valvular papillae charac-
| v H teristic of the genus Ascaris ; but
11 I # other Helminthologists, who have
M 19 failed in detecting this organization,

refer the species to the genus
Oxyuris. Besides the papillae the
head presents a lateral, semi-obo-
vate membrane on each side, the
broader end being anterior. The
body soon begins to grow smaller,
and gradually diminishes to a su-
bulate straight extremity in the
female. In the male the posterior
extremity is thicker, and is spirally
inflected and terminates obtusely ;
the head is narrower than in the
female.

In the following tabular arrange-
ment of the internal parasites of
the Human body, they are disposed
3 classes to which they appear

^Natural resPectivety to belong according to
size of their organization.

female.)

ENTOZOA HOMINIS.

Classis PSYCHODIARIA, Bory St. Vincent.

1. Acephalocystis endogena, cui locus

Hepar, cavum Abdominis, &c.

2. Echinococcus Hominis, Hepar, Lien,

Omentum.
Classis POLYGASTRICA, Ehrenberg.

3. Animalcula Echinococci, Hepar, &c.

in Echinococco abdita.*
Classis PROTELMINTHA.

4. Cercaria Seminis, Semen virile.

5. Trichina spiralis, Musculi voluntarii.
Classis STERELMINTHA.

6. Cysticercus cellulosee, Musculi, Cere-

brum, Oculus.

7. Tffnia Solium, Intestina tenuia.

8. Bothriocepalus latus, Intestina tenuia.

9. Polystoma Pinguicola, Ovaria.

10. Distoma hepaticum, Vesica fellea.
Classis CGELELMINTHA.

11. Filaria Medinensis, Contextus cellu-

losus.

12. Filaria oculi, Cavum Oculi.

13. Filaria bronchialis, Glandulae bron-

chiales.

14. Tricocephalus dispar, Ccecum, Intes-

tina crassa.

15. Spiroptera hominis, Vesica urinaria.

16. Strongylus gigas, Ren.

17. Ascaris lumbricoides, Intestina tenuia.

18. Ascaris vermicularis, Intestinum rec-

tum.

ANATOMY OF THE ENTOZOA.
Tegumentary System. — There are few spe-

* These may be considered rather as the Para-
sites of the Echinococcus than of the human sub-
ject.

cies of the Sterelmintha in which a distinct
external tegumentary covering can be demon-
strated. In the Cystic, Cestoid, and most of
the Trematode worms, the parenchymatous
substance of the body is simply condensed at
the surface into a smooth and polished corium
of a whitish colour, without any development
of pigmental or cuticular layers. The various
wrinkles and irregularities, which the super-
ficies of these Entozoa frequently presents,
result from the action of the contractile tissue
of the corium : this substance, in the larger
Tcenitf, begins to assume a fibrous disposition,
and tears most readily in the longitudinal di-
rection ; it can be more distinctly demonstrated
as a muscular structure in the larger species
of Trematoda. By maceration in warm water
the rugae of the integument disappear; the
smooth external surface, so well adapted to
glide over the irregularities of a mucous mem-
brane, is then distinctly demonstrated; and,
when magnified, an infinite number of minute
pores, variously disposed, are seen perforating
the whole surface, especially in the Acantho-
cephalous worms. It is these pores which, in
the dead worm at least, allow a ready passage
to the surrounding fluid into the interstices of
the parenchyma, where it sometimes accumu-
lates so as to swell out the body to three or
four times its previous bulk ; and it may be
readily supposed, therefore, that the skin here
performs some share in the nutrient functions,
by absorbing a proportion of the mucous or
serous secretions in which the Entozoa are
habitually bathed.

In the Acanthocephala the skin, which is
but little extensible and friable, is united to
the subjacent muscular fibres by means of a
whitish spongy tissue which adheres to it most
strongly opposite the dorsal and ventral longi-
tudinal lines or canals. As, however, the skin
is with difficulty changed by maceration, while
the parts which it surrounds soon go into
putrefaction, it can thus be easily separated
and demonstrated as a distinct substance. It
presents no definite fibrous structure under the
microscope, and tears with equal facility in
every direction.

In a large Trematode worm, the Distoma
clavatum, Rud., which infests the intestines
of the Albicore and Bonito, the body is pro-
tected by a crisp sub-diaphanous cuticle, re-
sembling in its structure and properties that of
the Echinorhynchus.

A similar covering may be demonstrated
very readily in the genus Linguatula, among
the Calelmintha, and can be separated, but
with more difficulty, from the subjacent mus-
cles in the Ascarides. In the great Round-
worm (Ascaris lumbricoides) the integu-
ment is smooth and unctuous, is more exten-
sible in the longitudinal than the transverse
directions, tears with an unequal rupture like
a thin layer of transparent horn, and preserves
its transparency in solutions of corrosive sub-
limate, alum, and in alcohol. In this species,
in which the digestive canal is completely de-
veloped, it is worthy of remark that the mi-

croscope does
cuticle, as in

not demonstrate pores in the
the external covering of the

ENTOZOA.

127

Echinorhynchus and other sterelminthoid
worms ; but a series of extremely minute close-
set parallel transverse lines are brought into
view, which are permanent, and depend on
the texture of the epidermoid substance itself.

Although a distinct and general epidermic
covering cannot be demonstrated in the more
simple Sterelm'mtha, the soft bodies of which
entirely dissolve after a few days' maceration,
and which, in animals examined soon after
death, are often found in consequence to have
lost their natural form, and to have degenerated
into a kind of mucus,* yet in most species
traces of the epidermic system are manifested
in some limited parts of the body : thus it ap-
pears in the form of hard transparent horny
hooklets around the oral proboscis in the Cystic
genera, as in the Cysticercus celluloste (Jig. 61),
and most of the Cestoid worms. In the Flori-
ceps, Cuv., these recurved spines are arranged
along the margins of four retractile tentacles,
which thus serve to fix the worm to the
slippery membranes among which it seeks its
subsistence. In the Trematode worms epider-
mic spines are seldom developed ; the species
•which infests the human subject (Distoma
hepaticum) presents no trace of them. When
they exist in this order, they are either confined
to the head, or are at the same time spread over
a greater or less proportion of the surface of
the body. Of the first disposition we have an
example in the Gryporhynchus pusillus, (a tre-
matode worm infesting the intestines of the
Tench,) which manifests an affinity to the
Tten'us armata in its proboscis armed with six-
teen strong recurved spines arranged in a
double circular series. In the Distoma trigo-
nocephalum there are two straight spines on
each side of the head. In Distoma armatum
the head is entirely surrounded by similar
straight spines. In Distoma ferox the head
bears a circle of recurved spines. In Distoma
denticulatum the head is surrounded by a series
of large straight spines, and there is a series
of smaller spines around the neck. In Dis-
toma spimtlosa the anterior part of the body is
beset with reflected spines ; and in the Dis-
toma perUttum, Nord., the whole surface of the
body is armed with hooklets, arranged in

Fig. 74.

Proboscis of Echinorhynchus gigai, magnified.
9 Rudolphi, Hist. Entoz. i. p. 230.

transverse rows, each being supported on a
cutaneous prominence and bent backwards,
(Mt.fe.91).

For a description of the complicated horny
and cartilaginous parts of the dermo-skeleton,
which enter into the mechanism of the suckers
of the worms belonging to the genera Diplo-
zoon and Octobothrium, we are compelled from
want of space to refer the reader to Nordmann's
Mikrographische Beitrage, (Erstes Heft.)

In the Acanthocephala the head, as the name
implies, is armed with recurved spines or
hooks, which are arranged in quincunx order
around a retractile proboscis, (Jig. 74) ; and,
in addition to these, some species have smaller
and less curved spines dispersed over the neck
or body.

Among the Calelmintha the genus Lingua-
tula is remarkable for the development of four
large reflected spines, arranged two on each
side the central mouth ; and which can be par-
tially retracted within depressions of an elon-
gated semilunar figure. The worm attaches
itself so firmly by means of the horny hooks
that it will suffer its head to be torn from its
body rather than quit its hold when an attempt
is made to remove it while alive. In the
Trichocephalus uncinutus the truncated head
presents at its anterior margin a series of hard
reflected hooks continued directly from the
integument. In the Strongylus armatus, which
has sometimes a singular nidus in the me-
senteric arteries of the Horse and Ass, the
globose head is terminated anteriorly by straight
spines, but in the Strongylus dent at us with
hooklets. Lastly, we may notice the very
singular worm found by Rudolphi in the
O3sophagus of the Water-hen, and which he calls
the Strongylus horridus, where the body presents
four longitudinal rows of reflected hooklets.

The epidermic processes, when thus traced
through the different orders of Entozoa, pre-
sent but few modifications of form, and
have little variety of function ; the straight
spines at the mouth serve to irritate and in-
crease the secretion of the membrane or cyst
with which the worm is in contact; the re-
curved hooklets serve as prehensile instru-
ments to retain the proboscis and the worm
in its position; and when they are spread
over the surface of the body, they may have
the additional function of aiding in the loco-
motion of the species, analogous to the spines
which arm the segments of the (Estrus, which
passes its larva state, like an Entozoon, in the
interior of the stomach and intestines of a
higher organized animal.

Muscular system. — Although in every order
both of the Parenchymatous and Cavitary
worms, living specimens have been observed
to exhibit sufficiently conspicuous motions, yet
the muscular fibre is not always distinctly eli-
minated in them. In the Cysticerci, however,
Rudolphi describes two bundles of fibres as
arising from the inferior part of the body, and
expanding upon the upper pail of the cyst.
We have traced corresponding fibres extending
to the head in a large Cysticercus tenuicollis;
which fibres were doubtless the principal agents

128

ENTOZOA.

in retracting the head within the terminal cyst ;
and this part, in the same specimen also, pre-
sented a remarkably distinct series of transverse
striae, indicating most probably the circular
fibres which contract the cyst in the transverse
direction, and protrude the proboscis.* This
species of Hydatid, which is common in the
abdomen of Sheep, where it is either sus-
pended in a cyst to the mesentery or omen-
turn, or embedded in the liver, &c. has been
the subject of numerous observations, and is
generally selected to demonstrate the muscular
phenomena in an animal of very simple orga-
nization. When extracted from a recently
killed sheep, and placed in water at the blood-
heat, the cyst may then be observed to become
elongated, and agitated with undulatory move-
ments ; the retracted part of the body is thrust
forth, and again, perhaps, drawn in ; during
the latter action the anterior part of the cyst
becomes wrinkled and is drawn back, gliding
into the posterior part of the cyst; the anterior
part of the body is at the same time retracted,
and is received into the posterior ; and thus by
degrees the head and all the body become
concealed in the terminal cyst.

In the Cestoidea the muscular structure is
indicated slightly by impressions on the sur-
face of the body, but it is seldom that a distinct
layer of muscular fibres can be demonstrated.

To the worms of the genus Caryophylleus
both Zeder and Rudolphi agree in ascribing
longitudinal fibres, which extend along the
anterior part of the body and transverse
fibres, which are conspicuous in the pos-
terior segments. In the T&nia both trans-
verse and longitudinal strata of fibrils are stated
to exist,f obscure indeed, or almost impercep-
tible in the smaller species ; but more evident
in the larger specimens, in which, according to
Rudolphi, each segment has in general its own
strata, whence it enjoys, for some time after
being separated from the rest of the body,
distinct and peculiar motions; and such joints
have been described as distinct species of En-
tozoa, under the name of Cucur-
Fig. 75. bit'ina. In the Bothriocephalus
latus, on the other hand, the lon-
gitudinal fibres are continued from
one joint to another, whence the
segments are less readily separable,
and a common and continuous co-
vering may be dissected from off
the body of this species.

Living Taeniae placed in warm
water exhibit undulatory motions.
The body of one of these worms is
sometimes found to be tied at some
part in a complicated knot, as seen
in jig. 75, doubtless by means of
these motions. The Ttenia solium,
when recently expelled from the
body by the irritation of a vermifuge
solium. remedy, is occasionally contracted
to the length of a few inches, the

* See Preparation, No. 409 A, Physiological
Series Mus. Roy. Coll. of Surg. Catalogue, vol. i.
p. 115.

t Rudolphi, Hist. Entoz. i. p. 223.

segments appearing as close-set transverse striae ;
when placed in water, after a few hours it will
have returned to a length of as many feet.
Werner* relates an instance of a Taenia which
extended from the anus of a patient to the
length of three feet, and which returned itself
almost wholly into the intestine, the dependent
part being drawn upwards by the superior.
Other and still more extraordinary instances of
the movements of the Cestoid worms are on re-
cord ; but that the separated joints of the Ttenia
solium should be able to creep several feet up a
perpendicular wall could scarcely gain a mo-
ment's credit, if the fact were not related by
no less distinguished a naturalist than Pallas.f
In general the muscular fibres cannot be
observed in the diaphanous bodies of the
smaller Trematoda, yet every part is endowed
with active contractility : in the larger species,
however, both longitudinal and transverse strata
of fibres may be demonstrated in the tegumen-
tary muscular covering of the body ; both which
we have distinctly seen in the large Distoma
clavatum. The muscular fibres of the aceta-
bula are disposed in two series, one radiating
from the centre to the circumference, the other
in concentric circles. The muscular tissue is
also well developed around the base of the
sucker, by which the animal is enabled to pro-
trude them from the surface.

In the Planaria, in which, as in the T<zni<e,
according to our observations, the muscular
system is indicated only by striae on the super-
ficies of the apparently homogeneous paren-
chyma, the phenomena of muscularity are
strikingly displayed in the varied and energetic
actions of the living animal. They lengthen,
shorten, widen, contract, or contort the body in
various degrees and directions : their mode of
locomotion on a solid plane is by an insen-
sible undulation, or successive approximation
of small proportions of the body, producing
a gliding movement, as in the Slug; and the
same actions take place in swimming through
the water, except that the body is reversed ;
and the ventral surface turned upwards, as in
the Carinaria and other aquatic Gastropods.
When seizing a living prey, as in Jig. 76, the
contractions of the body
Fig. 76. are more vigorous and

extensive.

In the Echinorhynchus
the muscular fibres are
of a whitish colour, semi-
transparent, and of a ge-
latinous appearance; they
Planaria lactea (B), are eminently contractile,
feeding on a Nais. and readily respond to
the application of both
chemical and physical stimuli. Cloquet ob-
served them to contract under the influence of
the galvanic current six hours after the cessation

* As quoted by Rudolphi. ' Taenia ad trium
ulnarum longitudinem ex mulieris ano propen-
dens, in casu qnem Wernerus (1. c. 47) refert,
tola fere in pristinum hospitium rediit, pars pro-
pendens itaque a superiore sursum ducta : similes
oinnino casus Andryus habet.'— Ibid. p. 223.

t Also quoted by Rudolphi, p. 223.

ENTOZOA.

129

of all spontaneous movement. The general
muscles of the body are disposed in two layers,
of which the fibres of the external are trans-
verse, those of the internal longitudinal.

With respect to the disposition of the mus-
cular system of the Nematoid worms, a dif-
ference of opinion is entertained by some ex-
perienced comparative anatomists.

Professor De Blainville* describes, in the
Ascaris lumbricoides, the external stratum of
muscular fibres as being longitudinal, while
the internal, he observes, are evidently trans-
verse, and much more numerous at the an-
terior than the posterior part of the body.
M. Cloquet, on the contrary, in his elaborate
monograph on the Ascaris lumbricoides, states
that the exterior layers of muscular fibres are
transverse, and the internal longitudinal. In
a large specimen of the Strongylus gigas, Rud.,
which we have dissected and examined micro-
scopically for the muscular system, we find
that a very thin layer of transverse fibres ad-
heres strongly to the integument, the fibres
being imbedded in delicate furrows on the
internal surface of the skin ; within this layer,
and adhering to it, but less firmly than the
transverse fibres do to the integument, there
is a thicker layer of longitudinal fasciculi,
which are a little separated from one another,
and distributed, not in eight distinct series,
but pretty equally over the whole internal
circumference of the body. Each fasciculus
is seen under a high magnifying power to be
composed of many very fine fibres, but these
do not present the transverse striae which are
visible by the same power in the voluntary
muscular fibres of the higher animals. The
longitudinal fibres are covered with a soft
tissue composed of small obtuse processes,
filled with a pulpy substance, arid containing
innumerable pellucid globules, and at the an-
terior extremity of the body this tissue assumes
a disposition as of transverse fasciculi (fig. 79).
In the Ascaris lumbricoides similar internal
transverse bands are shown in Jig. 88, e, e, and
are those which Professor Blainville regards
as muscular, and Cloquet as vascular organs.
We cannot detect a tubular structure in these
parts, neither have they the texture and con-
sistence of the true fibrous parts : they are soft
pulpy substances, doubtless connected with
the nutritious functions, and probably the or-
gans of absorption.

Besides the general muscular investment of
the body, there are distinct muscles in most
of the Entozoa, developed for the movement
of particular parts, as the retractile hooks of the
Linguatula and Porocephalus, and the probo-
scides of the Cestoid and Acanthocephalous
worms. Of the latter organ the Echinorhynchus
gigas offers a good example. The proboscis in
this species (Jig. 77) is a short, firm, elastic,
cylindrical tube,buried with its appropriate mus-
cles in the neck of the animal, as in a sheath; and
having its anterior extremity (a, b} terminated

* Dictionnaire des Sciences Naturelles, torn. iii.
App. p. 40.
f Anatomic de 1'Ascaride Lombricoide, p. 17.

VOL. II.

Retracted proboscis and its muscles, Echynorhynchus
gigas. Cloquet.

by a spherical eminence armed with four rows
of recurved spines. The retractor muscles are
four in number, two superior and two inferior,
(f, g,) flattened, elongated, and of a triangular
figure. They are continuous at their base or
posterior extremity, with the longitudinal fibres
of the body ; their anterior extremity, which
is extremely delicate, is inserted into the poste-
rior part of the proboscis. The protractile mus-
cles (c, cT) are also four in number, short but
strong, and forming, as it were, a sheath to the
proboscis ; they are attached to the anterior
part of the tegumentary sheath, and pass back-
wards to be inserted into the posterior extremity
of the proboscis in the intervals left by the
retractor muscles. The motions of the pro-
boscis thus liberally supplied, are, as might be
expected, more lively than those exhibited by
any other part of the body. When it is drawn
back into its sheath by means of the retractor
muscles, the booklets seem to be drawn close
to the side of the bulbous extremity, whence
we may infer that these also have their appro-
priate muscles.

Nervous system. — The Entozoa in which
the nerves can be most easily and distinctly
demonstrated, are the Linguatula t&nioides
and the larger species of the Nematoidea,
especially the Strongylus gigas.

In the Linguatula a proportionally large
ganglion (g, fig. 78) is situated immediately
behind the mouth, and below the oesophagus,
which is turned forward in the figure, at o;
small nerves (h, i, /c) radiate from this centre to
supply the muscular apparatus of the mouth
and contiguous prehensile booklets; and two
large chords (/, /) pass backwards and extend
along the sides of the abdominal aspect of the
body to near the posterior extremity, where

1-80

ENTOZOA.

Fig. 78. they gradually become

expanded and blended
with the muscular tissue.
In the Strongylus
gigaSj a slender nervous
ring (a, a, jig. 79) sur-
rounds the beginning of
the gullet, and a single
chord is continued from
its inferior part and ex-
tends in a straight line
along the middle of the
ventral aspect (c, <f) to the
opposite extremity of the
body, where a slight
swelling is formed im-
mediately anterior to the
anus, which is surround-
ed by a loop (e) analo-
gous to that with which
the nervous chord com-
menced. The abdominal
nerve is situated internal
to the longitudinal mus-
cular fibres, and is easily
distinguishablefromthem
with the naked eye by
its whiter colour, and the
slender branches (b, b)
which it sends off on each
side. These transverse
twigs are given off at
pretty regular intervals of
about half a line, and
may be traced round to
nearly the opposite side
of the body. The entire
nervous chord in the fe-
male of this species passes
to the left side of the
vulva, and does not di-
vide to give passage to
the termination of the
vagina, as Cloquet de-
scribes the corresponding
ventral chord to do in
the Ascaris Lumbricoides.
In the latter species, arid
most other Nematoidea, a dorsal nervous chord
is continued from the oesophageal ring down the
middle line of that aspect of the body corres-
ponding to the ventral chord on the opposite
aspect; but we have not found the dorsal chord
in the Strongylus gigas. The nervous system
in the latter Entozoon obviously therefore ap-
proximates to that of the Anellides ; but it differs
in the absence of the ganglions, which in all
the red-blooded worms unite at regular inter-
vals two lateral nervous columns ; it resembles
on the other hand most closely the simple and
single ventral chord in the Sipuncidus.

Living Ascarides are sensible to different
mechanical stimuli applied to the surface of
the body, and the sudden and convulsive
movements which take place when alcohol,
Vinegar, or alum-solution are applied to the
mouth, would seem to imply that they possess
a sense of taste : to light, noise, or odour they

Nervous system and fe-
male organs of genera-
tion of Linyuatula tae-
nioides, magnified.

Commencement and termina-
tion of the nervous system,
Strongylus gigas, magnified.

Fig. 79. are, as might be ex-

pected from the
sphere of their ex-
istence, totally in-
sensible.

In those Entozoa
which infest the parts
of an animal body,
where they may be
exposed to the influ-
ence of light, as the
gills of fishes, we
should not be un-
prepared to meet
with coloured eye-
specks, or such sim-
ple forms of the or-
gan of vision as oc-
cur in Infusoria and
other invertebrate
animals of a low
grade of organiza-
tion. Nordmann de-
tected four small
round ocelli, of a
dark-brown colour,
in the Gyrodactylusauriculatu!>,a.Cestoid worm,
found in the branchial mucus of the Bream
and Carp ; the eye-specks are situated a little
way behind the head, and "yield on pressure a
blackish pigment. V. Baer observed two
small blackish ocelli behind the orifice of the
mouth in the Polystomum Integerrimum, a
Trematode species, which infests the urinary
or allantoid bladder of the Frog and Toad.
Now this large receptacle is well known to
contain almost pure water ; and as the Poly-
stomum is very closely allied to the Planarite,
which habitually live in fresh water, it is pro-
bable that the allantoid bladder may be only
its occasional and accidental habitation. With
respect to the Planaria these are almost univer-
sally provided with eye-specks, varying in num-
ber from two, as in the P lunar ia lactea, (Jig.
80, A) to forty, of a brown or black colour, the
external covering of which is tran-
Fig. 80. sparent and corneous. From the
A experiments of M. Duges* on
these non-parasitic Sterelmintha,
we learn that when the solar light
is directed to the head, they escape
from its influence by a sudden move-
ment, and they also give unequi-
vocal, though less energetic, proofs
of their subjection to the influence
of diffused and artificial light. The
temporary ocelli observed in the
Planaria young of certain species of Dis-
lactea. toma^ will be presently noticed.

* Annales des Sciences Naturelles, 1828, p. 10.

t Conf. also Rudolph!, Synops. Entoz. p. 442,
where, in the description of the Scolex polymor-
phus, a Cestoid worm infesting the intestines of
Fish and Cephalopoda, he observes, " puncta duo
volo corporis albi sanguinea, saepe iulgentia, qualia
nullis in Entozois aliis videre licuit, qua3que in
Gobii minuti Scolece vasa duo rubra parallela pone
caput incipientia et retrorsum ducta, in corpore
autem evanida, cffingere observavi."

ENTOZOA.

131

Digestive organs. — We have already alluded
to the two leading modifications of the ali-
mentary canal, on which the binary division
of the Entozoa of Rudolphi is founded, viz.
into Sterelmintha or those in which the nu-
trient tubes, without anal outlet, are simply
excavated in the general parenchyma, and into
the Cttlelmintha, in which an intestinal canal,
with proper parietes, floats in a distinct ab-
dominal cavity, and has a separate outlet for
the excrements. In both these divisions the
mouth is variously modified, so as to afford
zoological characters for the subordinate
groups; and the alimentary canal itself in
the Sterelmintha presents several important
differences of structure.

Cystica. — The Cystic worms are generally
gifted, as in the species (Cytticcmu cellulose)
which occasionally infests the human subject,
w ith an uncinated proboscis for adhering to and
irritating, and four suctorious mouths for ab-
sorbing the fluid secreted by, the adventitious
cyst in which they are lodged. In the larger
Cysticerci lateral canals may be traced from the
suctorious pores extending down the body
towards the terminal cyst, but they appear
not to terminate in that cavity, the fluid of
which is more probably the result of secretion
or endosmosis. We cannot, however, partici-
pate in the opinion of Rudolphi,* that the
retracted head derives nutriment from the
surrounding fluid of the caudal vesicle, for if
that were the case, where would be the neces-
sity for an armed rostellum in addition to
the absorbent pores ? The frequency with
which the Cysticerci are found with the head
so retracted, may be attributed to the in-
stinctive action arising from the stimulus of
diminished temperature and other changes
in the surrounding parts occasioned by the
death of the animal in which the hydatid
has been developed.

Ceatoidea. — In the Cestoidea the digestive
apparatus commences for the most part by two
or four oral apertures, to which, in many spe-
cies (the Ta-nitf armatte), a central uncinated
proboscis is superadded, as in the Cysticerci.
Sometimes the mouths are in the form of oblong
pits or fossae, as in the Bothriocephalus latus, and
the allied species grouped under the same gene-
ric name ; or they have the structure of circular
suctorious discs, as in the Taenia solium and
other true Tania.-)- In both genera two alimen-
tary canals are continued back wards in a straight
line near the lateral margins of the body (e, e,

* •' Osculis tamen canalibusque dictis omnem
aquae vim vesica caudal! collectam parari potuisse
vix credibile, sed hac parata vermem eandem
absorbere ideoqiie semper ferecaput huic immissum
offerre, longe aliam vero fluidi advehendi viam
dari, plurima suadent." — Hist. Entoz. i. p. 279.

t Many beautiful preparations, showing the
nutrient canals of the Tania solium injected with
coloured size and quicksilver, are preserved in the
Hunterian collection, (see Nos. 843, 844, 845.)
These were prepared, during the life-time of John
Hunter, and were presented to that great anato-
mist by Sir Anthony Cailisle, by whom they are
described in the ' Observations upon the Struc-
ture and (Economy of Taeniat,' in the second vo-
lume of the Linnaean Transactions, (1794).

fig. 90), and are united by transverse canals
(f\ ft /g-90) passing across the posterior margins
of the segments. These connecting canals are
relatively wider in the Teenia solium than in the
Bothriocephalus latus, their size apparently
depending on the length of the segments,
which is much greater in the former than the
latter. Neither the transverse nor the longi-
tudinal vessels undergo any partial dilatations.
The chief point at issue respecting the digestive
organs of the Tape-worms is, whether the nu-
triment is imbibed by them through the pores
which occur at the sides or margins of each
joint, or whether the entire body is dependent
for its nutriment upon the anterior mouths from
which the lateral canals commence. The re-
sults of numerous examinations, which I have
made with this view, both on Bothriocephali*
and Taeniae, have uniformly corresponded with
those of Rudolphi, and I entirely subscribe to
the opinion of that experienced helminthologist,
that the marginal or lateral orifices of the seg-
ments are exclusively the outlets of the gene-
rative organs.

In some species of Tape-worm, as the Tania
sphtenocephalus, in which no ovaria have been
detected, there has been a corresponding ab-
sence both of lateral and marginal pores, while
the lateral longitudinal canals have been pre-
sent and of the ordinary size. In the Tania
solium the generative pores being placed at
one or other of the lateral margins of the seg-
ments, the ducts of the ovary and testis (g, h,
fig. 90) cross the longitudinal canal of that
'side, and give rise to a deceptive appearance,
as if a short tube were continued from the
alimentary canal to the pore. But in the
Bothriocephalus latus and Bothriocephalus
Pythonis the generative pores open upon the
middle of one of the surfaces of each segment,
and in these it is plain that the lateral nu-
trient vessels have no communication with
the central pores. The orifices of the segments,
in short, correspond with the modifications of
the generative apparatus, while the nutrient
canals undergo no corresponding change.
Nutrition may be assisted by superficial ab-
sorption ; and, as Rudolphi suggests,! the se-
parated segments may for a short time imbibe
nutriment by the open orifices of the broken
canals ; but setting aside cutaneous absorption
and the more problematical action of the rup-

* Principally on that species which infests the
intestines of the large serpent commonly exhibited
in this country the Python Tigris, Band. And we
invite the attention of comparative anatomists
interested in this point to an injected preparation
of one of these worms in the Museum of the Royal
College of Surgeons, No. 846 A.

t " Al. Olfers (de veget. et anim. p. 35)
articulos Tteruae singulos ope absorptionis cutaneae
perparum, maxime autem ope osculi marginalis
nutriri contendit, sed osculum hoc vere ad genitalia
pertinfre in capite insequente evincam. Si cl.
vir absorptionem cutaneam minoris aestumat, hac
de re non litigabo, sed res alio modo explicari
potest. Annon enim ad vasa linearia nutnentia,
utrinque longitudinaliter decurrentia, si artituius
solufus est, in utroque ejus fine utrinque hiantia,
absorbendi officium deferri posset." — Synops. Entoz.
p. 585.

K 2

132

ENTOZOA.

tured vessels, the head of the Tape-worm is
the sole natural instrument by which it im-
bibes its nutriment, and it is to the expulsion
of this part that the attention of the physician
should be principally directed, in his attempts
to relieve a patient from these exhausting para-
sites.

Trematoda. — Four kinds of vessels or canals
are met with in the parenchymatous body of the
Trematode worms, viz. digestive, nutritive or
sanguiferous, seminal, and ovigerous. In the
genus Monostoma, the digestive canal is bifur-
cated, each branch traverses in a serpentine
direction the sides of the body, and they are
united, in some species, by a transverse com-
municating vessel at the caudal extremity ; in
others, as Monost. mutabile, they converge and
terminate in an arched vessel at the posterior
part of the body. They are of small size, and
not very clearly distinguishable from the sangui-
ferous vessels.

In the Distoma hepaticum, the digestive
organs are more distinctly developed. The
oesophagus is continued from the anterior pore,
and forms a short wide tube, shaped like an
inverted funnel. Two intestinal canals are
continued from its apex, which immediately
begin to send off from their outer sides short
and wide coacal processes, and continue thus
ramifying to the opposite end of the body,
but have no anal outlet. Rudolphi* states
that when successfully injected with mercury,
more minute vessels are continued from the
apices of the digestive canals, which form a net-
work over the superficies of the body. A similar
dendritic form of the digestive canal obtains in
the singular genus Diplozoon, discovered by
Nordmann in the gills of the Bream; the central
canal and ramified ccecal processes in this En-
tozoon are represented (Jig. 328, vol.i. p. 654,)
on that moiety, which is opposite the left hand
of the observer : on the other moiety the vascu-
lar system alone is delineated. The latter is not,
like the digestive canal, common to both halves
of the body, but consists of two closed systems
of vessels, each peculiar to its own moiety.
Two principal trunks, a, a, traverse the sides
of each moiety, preserving a uniform diameter
throughout their entire course. In the external
vessels marked a, a, Nordmann states that
the blood is conveyed forwards or towards the
head: in the internal ones, it passes back-
wards in the opposite direction. The latter
vessels commence by many minute branches
which unite in the space between the oral
suckers and the anterior extremity of the
body, and terminate between the disc and
suckers at the posterior extremity of the body.
The exterior or ascending vessels begin where
these disappear and pass towards the opposite
end of the body : both trunks freely inter-
communicate by means of superficial capil-
laries. The blood moves through them with
great rapidity, but without being influenced
by any contraction or dilatation of the vessels
themselves. The circulation continues for
three or four hours to go on uninterruptedly in

* Entoz. Synopsis, p. 583.

each moiety of the Diplozoon, after they have
been separated from one another by a division
of the connecting band. The blood itself is per-
fectly limpid. It should be observed, with refe-
rence to the above description, that the appear-
ance of circulatory movements in the vessels of
the Diplozoon paradoxum is ascribed by Ehren-
berg ( Weigmann's Archiven, 1835, th. ii.) and
Siebold ( Ibid. 1836, th. ii.) to the motion of
cilia on the inner surface of the vascular canals.

In the genus Diplostomum, in which the
nutritious and vascular systems characteristic
of the Trematoda are peculiarly well displayed,
(fig. 81,) a short and slightly dilated canal is
continued from the mouth, and soon divides
into two alimentary passages or intestines, e, e,
which diverge, and proceed in a slightly un-
dulating course, towards the hinder sacciform
appendage of the body, dilating as they de-
scend, and ultimately terminating each in a
blind extremity,/,/. The contents of this long
bifid blind alimentary canal are of a yellowish
brown colour, especially in old individuals,
and consist of a finely granular substance.
As there is no separate anal aperture, the crude
and effete particles are probably regurgitated
and cast out by the mouth, as in all other
Trematoda.

The posterior projection of the body, g,
Nordmann compares to the posterior appen-
dage in the Cercarue ; it is terminated by a
posterior aperture which seems to be the ex-
cretory outlet of some secerning organ ; since
a milky fluid is sometimes ejected from it
with force. In a species of Distoma (Distoma
clavatum, Rud.) which I recently dissected,

Fig. 81.

Digestive and nutrient canals, Diplostomum volvens,
magnified.

ENTOZOA.

133

there is a similar aperture which forms the
outlet of a vertically compressed sac situ-
ated between the chyle-receptacles (see Trans-
actions of the Zoological Society, plate 4, p. 381,
pi. 41, figs. 17, 18, d, g). In the Diplostomum
volvens Nordmann supposes the aperture in
question, h, to be the termination of a canal
continued from the oviduct. Besides this
canal the posterior appendage of the body is
occupied by a sac of a corresponding form
containing a milky fluid, i, t, and to which
the term of chyle-receptacle is given by Nord-
mann, as was previously done by Laurer to a
corresponding cavity in the Amphistoma coni-
cum. The nutritious contents of this canal
would seem to exude through the parietes of
the co3cal extremities of the intestines, as no
distinct aperture of communication is obvious.
Two vessels, k, k, are continued on each side
from the anterior and external part of the chyle
receptacle; they extend forwards to the anterior
third of the body, and are there brought in to com-
munication by a transverse vessel, /, /, which ex-
tends across the dorsal aspect of the body. From
the point of union of the transverse with the
external lateral vessels, a vessel is continued for-
ward on each side, appearing as the continuation
of the external lateral one. These vessels, m, m,
are reflected inward at the anterior angles of the
body, and unite in the middle line to form the
vessel, n, which may be regarded, according
to Nordmann, as representing the arterial
trunk, and which is continued to the posterior
extremity of the body, distributing branches on
each side throughout its whole length. Nord-
mann observed a circulation of fluid in the
vessels marked m, m, which was unaccom-
panied by any pulsation, and which may there-
fore be compared to the
cyclosis of the nutrient fluids
in the vessels of Polygas-
trica, Polypi, and other
Acrita, and is probably due
to the action of vibratile
cilia.

In a few species of Pla-
naria the mouth is terminal
and anterior, as in the
Distomata ; these form the
subgemis Prostoma of
Professor Duges.* In the
greater number of these non-
parasitic Sterelmintha the
alimentarycanal commences
from a cavity situated at the
middle of the inferior sur-
face of the body. A pro-
boscis or suctorious tube (a,
jig. 82}, varying in length
according to the species, is
contained in this cavity,
from which it can be pro-
truded, and the mouth is
situated in the form of a
round pore at the extremity
of this proboscis. The ac-
tion of this tube is well dis-

Fig. 82.

Dendritic digestive

cavity, Planaria

lactea.

* Duges, Annales des Sciences, 1828, p. 16.

played when a hungry Planaria makes an attack
upon a Nais ; it then wraps its flat body around
its prey (see Jig. 76,) and applies to it the extre-
mity of its trumpet-shaped sucker ; the red-
blood of the little Anellide is seen to dis-
appear from the part in contact with the sucker;
and if the body of the Nais be broken in the
conflict, the Planaria directs the extremity of
the proboscis to the torn and bleeding surface.
After a meal of this kind the digestive canals
of the Planaria are displayed by the red colour
of their contents, like the corresponding parts
of the Liver-fluke when filled with bile, and
they greatly resemble the latter in structure ;
instead of two canals, however, three are con-
tinued from the base of the proboscis ; one of
these is central (6), and passes upwards to the
anterior extremity of the body, distributing its
wide coeca on either side ; the other two (c, c)
descend, almost parallel to one another, and
give off their coecal processes chiefly from the
outer margin, as in the Distoma. The Plarutrue
are, equally with the parasitic Trematoda, de-
void of an anus : and the remains of Poly-
gastric infusories swallowed by them have been
seen to be regurgitated by the proboscis. Mi-
nute nutrient vessels are continued from the
extremities of the intestinal cceca, and form a
very fine cutaneous network, which communi-
cate with a mesial and dorsal canal and two
lateral vessels, as in the Diplostomum.

Some species of the Trematode Entozoa are
infested by parasitic Polt/gastrica which belong
to the Monads : Nordmann observed some
brown corpuscles by the sides of the alimen-
tary canal of a Diplostomum, which contained
minute particles in continual and lively motion.
On crushing the corpuscles between plates of
glass an immense concourse of the moving
atoms escaped : they were smaller than the
Monas atomos of Miiller, of an oval form, and
of a clear yellow colour; their movements were
very singular : they whirled rapidly round on
their axis, then darted forward in a straight
line, whirled round again, and again darted
forward. When we consider that the Diplos-
tomum itself does not exceed a quarter of a
line in length, and that the aqueous humour
of a single eye serves as the sphere of existence
to hundreds of individuals, what views does
the fact of the parasites of so minute an Ento-
zoon open of the boundless and inexhaustible
field of the animal creation !

Acanthocephala.—The worms of this order,
although in external form, in the development
of the tegumentary and muscular system, and
above all in their direcious generation, they ap-
proach very closely the Nematoid Worms, yet
preserve the distinguishing character of the
Sterelminthoid class in the structure of the
digestive organs. In the Echinorhynchus
gigas the mouth is an extremely minute pore,
situated on a projectile armed proboscis, the
structure of which we have already described.
From its posterior part are continued two long
cylindrical canals (e, e, Jigs. 83, 84) which ad-
here closely to the muscular fibres by their outer
side, and project on the opposite side into the
triangular cavity (h, jig. 84) left between the

134

ENTOZOA.

Fig. 83. ovaries in the female and
testes in the male. They
are extremely minute at
their commencement, but
increase so as to be readily
visible in the middle of
their course. They are trans-
parent and irregularly dila-
ted or sacculated at inter-
vals. Posteriorly they ter-
minate in a cul-de-sac, and
have no anal outlet. They
contain a transparent in-
odorous albuminous liquid,
give off no visible lateral
branches, and do not com-
municate together in any
part of their course. Be-
sides these canals we find
in the cavity of the body
of an Echinorhynchus two
long wavy tubes called
lemnisci, (d, d, fig. 83).
They are attached to the
lateral parts of the neck by
an extremely attenuated an-
terior extremity, float freely
in the remainder of their
extent, and terminate in an
enlarged obtuse and imper-
forate extremity. They are
of a whitish colour, tran-
sparent in the living worm,
but become opake after
death; they present consi-
derable variety of form, and
would seem to be highly
irritable parts, since they are
not unfrequently found fold-
ed into a packet, or twisted
both together, and, turned
to one side of the body.
When examined with a high
microscopic power, a tran-
sparent vessel is perceived
running through the centre
and ramifying as it descends
in the substance of the lena-
niscus, which is soft, fragile,
and granular. Cloquet com-
pares these organs to the
nutrient processes which
project into the abdominal
cavity of the Ascaris, and
they are also regarded by
Goeze, Zeder,and Rudolphi
as belonging to the organs
of nutrition.

In the Ccelelmintha or
Cavitary Entozoa, the ali-
mentary canal is single and of large size, and
extends nearly in a straight line from the mouth
to the anus, which are at opposite extremities
of the body. With regard to the existence of an
anal outlet, the parasitic Entozoon, ( Syngamus
tracftcalis, Siebold,) which infests the windpipe
of our common Gallinaceous Birds, presents an
exception. It was suppored by Montague to be
a single individual with two pedunculate mouths :

Digestive and gene-
rative organs, Echi-
norhynchus gigas,
female.

Transverse section of Echinorhynchus gigas.

and by Rudolphi was placed in the same group
as Distomafurcatum, which is a true double-
necked Trematode worm. But the digestive
system has the essential character of the ccelel-
minthic structure, the intestine floating freely
in an abdominal cavity. The orifice at the
extremity of the smaller or male branch leads
to a muscular oesophagus, which is continuous
with a somewhat broader reddish-brown intes-
tine, continued in a tortuous manner down the
neck, and terminating in a eu!-de-sac prior to
the confluence of the extremity of this branch
with the body of the female. The mouth of
the larger branch, which is the true continua-
tion of the larger and single body, leads first
to a horny basin-like cavity, which communi-
cates by an opposite pore, surrounded by six
horny hooks or teeth, with the oesophagus,
from which a similar reddish-brown intestine
is continued, but in a more tortuous manner
than in the male, through the whole body, ter-
minating in a cul-de-sac at the caudal extre-
mity. In both intestinal canals are molecules
of apparently the colouring matter of blood.
Their inner surface is reticulate.

In the freedom of these intestines from the
muscular parietes of the body, and in the cy-
lindrical form of the latter, we have a close
affinity to the Nematoid type: but the intestine
is blind — without an anal outlet. It is not,
however, bifurcate, as in the true Trematoda.

In the genus Lingua tula or Pentastoma of
Rudolphi, the intestine is a simple straight
tube, and is surrounded by the convolutions
of the oviduct : the two intestinula caca with
which Rudolphi describes the alimentary canal
as being complicated,* appertain to the gene-
rative system, and communicate exclusively
with the oviduct : the intestine terminates by
a distinct anus at the posterior extremity of
the body.

In the Nematoidea the intestine is also
frequently concealed in a part of its extent by
the coils of the genital tubes, but these are
disposed in masses by the side of the alimen-
tary canal, and not wound around it as in the
Linguatula : in most species the alimentary
canal is attached to the internal parietes of the
abdominal cavity by means of numerous small
laminated or filamentary processes.

In the Strongyha gigas the mouth (A., fig.
71) is surrounded by six papillae; the cesopha-

* Synopsis Entoz. p. 584.

ENTOZOA.

135

gus (b,fig. 95) is round and slightly contorted,
and suddenly dilates at the distance of about two
inches from the mouth into the intestinal canal;
there is no gastric portion marked off in this
canal by an inferior constriction, but it is conti-
nued of uniform structure, slightly enlarging
in diameter to the anus. The chief pecu-
liarity of the intestine in this species is that
it is a square and not a cylindrical tube, and
the mesenteric processes pass from the four
longitudinal and nearly equidistant angles
of the intestine to the abdominal parietes.
These processes, when viewed by a high mag-
nifying power, are partly composed of fibres
and partly of strings of clear globules, which
appear like moniliform vessels turning around
the fibres. The whole inner surface of the
abdominal cavity is beset with soft, short,
obtuse, pulpy processes, which probably im-
bibe the nutriment exuded from the intestine
into the general cavity of the body, and carry
it to the four longitudinal vessels, which tra-
verse at equal distances the muscular parietes.
The analogous processes are more highly de-
veloped in the Ascaris lumbricoides, in which
species we shall consider the digestive and
nutritive apparatus more in detail.

The mouth (d, fig. 87 and fig. 85) is sur-
rounded with three tubercles, of which one is
superior («, fig. 85), the others inferior (6, 6) ;
they are rounded externally, triangular inter-
nally, and slightly granulated on the opposed
surfaces which form the boundaries of the oral
aperture (c). The longitudinal muscles of the
body are attached to these tubercles; the dorsal
fasciculus converges to a point to be inserted
into the superior one ; the ventral fasciculus
contracts and then divides to be inserted into
the two which are situated below. By means of
these attachments the lon-
gitudinal muscles serve to
produce the divarication of
the tubercles and the open-
ing of the mouth ; the tu-
bercles are approximated by
the action of a sphincter
muscle.

The oesophagus (e,fig.
Head and mouth of 87) is muscular and four
Ascaris lumbricoides. or five lines in length, nar-
row, slightly dilated pos-
teriorly, and attached to the muscular pa-

Fig. 86.

Fig. 85.

Transverse sectwn of Ascaris lumbricoides,

rietes of the body by means of slender, radiated
filaments : its cavity is occupied by three lon-
gitudinal ridges, which meet in the centre and
reduce the canal to a triangular form. The
CEsophagus is separated by a well-marked con-
striction from the second part of the digestive
canal, which in the rest of its course presents
no natural division into stomach and intestine.
The anterior portion of the canal is attached
by filaments, as in the Strongylus, to the pro-
cesses and lining membrane
Fig. 87. of the abdominal cavity. Those
d which come off from the sides

of the canal (d, d) communi-
cate with the nutritious vessels
and appendages, and in pass-
ing from the intestine they
diverge and leave on each side
a triangular space, of which
the base corresponds to the
lateral line or vessel (e, Jig.
86), and the apex to the side
of the intestine. These lateral
spaces are filled with a serous
fluid, and are continuous with
the common cavity contain-
ing the alimentary and gene-
rative tubes. About the mid-
dle of the body the intestine
becomes narrower, being here
surrounded and compressed
by the aggregated loops of the
oviduct or testis, and the me-
senteric processes or filaments
diminish in number, and at
last leave the intestine quite
free, which then gradually en-
larges to within a short dis-
tance of its termination (A).

The parietes of the intestine
are thin and transparent, and
easily lacerable ; they consist
of a gelatinous membrane, the
internal surface of which is
disposed in irregular angular
meshes and transverse folds,
which gradually disappear to-
wards the lower part of the
canal.

The soft obtuse processes
(f, ft fig. 86) analogous to
those which project from the
lining membrane of the abdo-
minal cavity in the Strongylus,
acquire a considerable deve-
lopment in the Ascaris. They
arise chiefly in the dorsal and
ventral regions, and are con-
tinued from numerous trans-
verse bands (e,e,jig.88} which
pass across the body from one
lateral absorbent vessel to the
other. In the anterior third
of the body these transverse
bands (vaisseaux nourriciers,
Cloquet,) are quite concealed

Digestive and gene*? the Presses in question
rative tubes, Ascari*( aPP<™lices nuumaers, Clo-
lumbricoides, male, quet), but are very conspicu-

136

ENTOZOA.

ous at the posterior part of the body. The
nervous chord passes at a right angle to the
transverse bands between them and the longi-
tudinal muscles, and sometimes is included in
loops of the former, as at d, fig. 88. Both the
pendant processes and the transverse bands are
composed of a homogeneous spongy tissue,
without any central cavity, and appear to form
a nidus of nutrient matter like the fatty omen-
tal processes in higher animals.

The longitudinal lines (c,c,^g. 86, 88), which
extend along each side the body of the Ascaris
Lumbricoides, and which are very conspicuous

Fig. 88.

Nutritive processes and vascular canals magnified,
Ascaris lumbricoides.

externally through the transparent integument,
consist each of a narrow flattened tract of opaque
substance, by some anatomists considered as
nervous, and a very slender vessel which ad-
heres closely to the outer side of the band.
The two bands become expanded at the an-
terior extremity of the body, and unite in
forming a circle around the oasophagus : the
vessels, on the contrary, become detached from
the bands, and pass transversely below the
oesophagus to anastomose together, forming a
simple loop or arch, the convexity of which is
anterior. By pressure the reddish fluid con-
tained in these vessels may be made to tra-
verse them backwards and forwards.

With respect to the accessory glands of the
digestive system of the Entozoa, I have hi-
therto met with them in two species only of
the Nematoidea, in both of which they pre-
sented the primitive form of simple elongated

unbranched cceca. The first being developed
from the commencement of the alimentary
canal, and co-existing with a pair of rudimen-
tal jaws, must be regarded as salivary organs.
They exist in a species of worm which
infests the stomach of the Tiger, and which
I have recently described under the name
of Gnathostoma aculeatum* They consist
of four slender elongated cceca, communi-
cating with the mouth, and gradually increas-
ing in size as they extend backwards into the
abdominal cavity, where they end each in a
cul-de-sac ; they are placed at equal distances
around the alimentary canal, and have no at-
tachment except at their open anterior extre-
mity. The length of each coecum is about
one-twentieth of the entire alimentary canal.
Their parietes under a high magnifying power
present a beautiful arrangement of spirally
decussating fibres. Their contents when recent
are clear, but become opaque when immersed
in alcohol. That the Gnathostoma is not the
larva of an insect is proved by the complete
development of the generative system, which
resembles that of the Ascarides, and by the
absence of a ganglionic nervous system.

The second example of an accessory digestive
gland occurs in a species of Ascaris infesting
the stomach of the Dugong : here a single
elongated ccecum is developed from the in-
testine at a distance of half an inch from the
mouth; and is continued upwards, lying by
the side of the beginning of the intestine, with
its blind extremity close to the mouth ; from
the position where the secretion of this coecum
enters the intestine, it may be regarded as re-
presenting a rudimental liver.f

Respiratory Organs. — The Entozoa have no
distinct internal or external organs of respi-
ration. The skin in many of the Trematoda
and Acanthocephala is highly vascular,! and
the circulating fluids in these worms may be-
come oxygenated by contact with the vascular
' mucous membranes of the higher organized
animals which they infest. In the Planarits
the surrounding water is renewed upon the
vascular surface of the body by means of the
currents excited by the action of vibratile
cilia; and the young of certain species of
Distomataj which pass the first epoch of their
existence under the form of Polygastric In-
fusoria, freely moving in water, are pro-
vided with superficial vibratile cilia arranged
in longitudinal rows; but these organs of lo-
comotion and adjuncts to the respiratory pro-
cess are lost when the Distomata resume their
position as parasites in the intestines of the
Fishes from which they were originally ex-
pelled.

Excretory glands. — As an example of an
organ of excretion, we may refer to the glan-
dular sac lodged in the enlarged extremity of
the Distoma clavatum, which opens externally

* Proceedings of the Zoological Society, Nov.
1836.

t See the Preparation, No. 429 A, Mus. Coll.
Surgeons, Phys. Catalogue, p. 121.

t Conf. Echinorhynchus vasculosus,Entoz.Synop.

ENTOZOA.

137

by a small orifice in the centre of that part,*
and the corresponding cavities from which a
clear or milky fluid is ejected by the posterior
pores of some smaller species of Distomata
and Diplostomata.-\

Organs of generation. — The generative sys-
tem in the Entozoa presents great varieties
in the form, structure, and combination of
its several parts. Sometimes the female or
productive organs alone are discernible. In
many Cestoidta, and in all the Trematoda,
the male gland is present and communicates
with the oviduct, so that each individual
is sufficient for itself in the reproductive
capacity. In the Acanthocephala and Ne-
matoidea the sexes are distinct, and a con-
currence of two individuals is required for
impregnation.

No trace of a generative apparatus has hither-
to been detected in the Cystic Entozoa. They
would seem to be gemmiparous, and to have
the reproductive power diffused over the whole
cyst, at least in the Acephalocysts, in which
the young are not developed from any special
organ, or limited to any particular part of the
cyst.

The ovaries in the most simple of the Ces-
toid worms, as the Ligula, are situated in the
centre of each joint, where they open by a
transverse aperture, from which projects a
small filamentary process or lemniscus, re-
garded by Rudolphi as a male organ. In the
Bothriocephali the ovaries have a similar po-
sition, and in the Bothriocephalus latus (Jig. 89)
assume a stellated figure, with
.F/g. 89. the aperture in the centre,
R tj which is situated in the mid-

dle of each joint. In the
Bothriocephalus microcephalus
the ovary consists of one or
two rounded corpuscles in the
centre of the joints, but the
generative orifices are margi-
nal and irregularly alternate,
and the oviducts may be dis-
tinctly seen passing backwards
to them.

In the T&nia Candelabra-
ria a sacciform ovary exists
in each segment, which sends
off an oviduct to the marginal
outlet. Besides which, ac-
cording to Rudolphi, there is
a longitudinal canal, uniting
Ovarian aperture* ^different ovaries together,
and ma, Bothrio- and undergoing a partial dila-
cephalus latus. tation at the anterior part of
each joint. — May not this be
the male organ ?

The androgynous structure of the generative
apparatus is very well displayed in the Tape-
worm of this country, the Tama Solium.

In each joint of this worm there is a large
branched ovarium (i, Jig. 90) from which a
duct (h} is continued to the lateral open-

* See Zool. Trans, pt. iv. vol. i. p. 381. pi. 41.
fig. 18. See Nordmann, loc. cit. p. 38.
t See Nordmann, loc. cit. p. 140.

Fig. 90.

Generative organs magnified, Taenia tolium.

ing. The ova are crowded in the ovary ;
and in those situated in the posterior segments
of the body, they generally present a brownish
colour, which renders the form of their recep-
tacle sufficiently conspicuous.* In segments
which have been expelled separately, we have
observed the ovary to be nearly empty, and it
is in these that the male duct and gland is
most easily perceived. For this purpose it is
only necessary to place the segment between
two slips of glass, and view it by means of a
simple lens, magnifying from twenty to thirty
diameters: a well-defined line (g), more slender
and opake than the oviduct, may then be
traced extending from the termination of the
oviduct, at the lateral opening, to the middle
of the joint, and inclining in a curved or

* The dendritic ovarian receptacles can also be
injected with mercury or coloured sizo, and they
have been regarded, but erroneously, as forming
part of the nutrient apparatus.

138

ENTOZOA.

slightly wavy line to near the middle of the
posterior margin of the segment, where it ter-
minates in a small oval vesicle. This, as seen
by transmitted light, is sub-transparent in the
centre and opaque at the circumference, indi-
cating its hollow or vesicular structure. The
duct, or vas deferens, contains a grumous se-
cretion ; it is slightly dilated just before its
termination.

In this species therefore, as also in Amphis-
torna conicum, the ova are impregnated in their
passage outward. But in several species of
Distomata, as D. clavigerum, ovatum, cirrige-
runij and in the Distoma hepaticum, the ova
escape by an aperture situated near the base of
the penis, and reciprocal fecundation exists.
The concourse of two individuals must also take
place in those species of the genus Monos-
tomum, which, like the Monostomum mutabile,
are viviparous, and in which the orifices of the
male and female parts are distinct.

All the Sterelmintha of the Trematode order
are androgynous; but the generative apparatus,
instead of being divided and multiplied as in
the Tania, is individualized, and its several
parts receive a higher degree of development.
We have selected the figure which Nordmann
has given of the Distoma perlatum, on account

Fig. 91.

Generative organs, Distoma perlatum, magnified.

of the clearness with which the several parts
are delineated, but it must be observed that it
deviates in some remarkable peculiarities from
what may be regarded as the Trematode type
of the reproductive organs.

The specimen is seen from the under side,
part of the parietes of the body having been
removed ; a is the oral aperture, b the oesophagus

seen through the transparent integument, c d
the windings of the beginning of the simple
digestive cavity, e e the two intestinal prolon-
gations, //' the dilated claviform co2cal ter-
minations of the intestines, g the two internal,
and h the two external trunks of the vascular
system proceeding to the anterior part of the
body; i is the great sacciform uterus, k ap-
parently glandular bodies contained therein,
/ m the two testes, which are beset internally
with small spines or cilia; n the projecting
cirrus from which the ova are expelled, o the
terminal dilatation of the oviduct which com-
municates with the testes, p p p p convo-
lutions of the oviduct which are filled with ova,
q q the mass of ova which lies above the ovi-
duct, and occupies almost the whole cavity
of the body, r r the passages by which the
ovaries communicate with the uterus or dilated
commencement of the oviduct.

The generative organs present some varieties
in the Planarite, but are essentially the same
as in the Distomata. In the Planaria lactea
the penis and oviduct are situated below, and
the two vesicular and secerning parts of the
apparatus towards the upper part of the body.
The male organ (a, fg. 92) consists, according

Fig. 92.

to the researches of Professor Duges, of two
parts, one of which is free, smooth, semi-
transparent, contractile, and always divided
into two portions by a circular constriction ;
it is traversed by a central canal, susceptible
of being dilated into a vesicle, and is open at
its free extremity, which is turned backwards ;
the second division is thicker, more opaque,
vesicular, adherent to the contiguous paren-
chyma, and receives two flexuous spermatic
canals (6, 6). The free portion of the penis is con-
tained within a cylindrical muscular sheath (c),
which is adherent to the circumference of the
base of the intromittent organ, and serves to
protrude it externally. This sheath commu-
nicates with the terminal sac of the female
apparatus near its outlet by a projecting orifice
(of). The oviduct (e) opens into the posterior
part of the terminal sac : it is a narrow tube
which passes directly backwards, and dividing
into two equal branches, again subdivides and
ramifies amongst the branches of the dendritic
digestive organ. Besides the ovary there are
two accessory vesicles (gand//), communicating
together by a narrow duct (f), and opening
into the terminal generative sac.

M. Baer twice witnessed the copulation of

ENTOZOA.

139

P 'lunar 'KB in the species Planaria torva. Upon
separating the individuals, he perceived a long
white tube projecting from the genital pore of
each, proving the reciprocity of fecundation.

Notwithstanding the complicated apparatus
above described, the Planaria; are remark-
able for their spontaneous fissiparous gene-
ration, and the facility with which detached
or mutilated parts assume the form and func-
tions of the perfect animal. Fig. 92, o, repre-
sents a Planaria lactea, with the anterior part
of the body artificially divided in the longitu-
dinal direction ; jig. 92, E, shews the same in-
dividual having two perfect heads, the result
of the preceding operation.

The female generative orgrans of the Lingua-
tula ( Pentasloma) t&nioides present a struc-
ture in some respects analogous to that of the
Di$loma perlatum : the ovary (n, n,jig. 78)
is a part distinct from the tubular oviduct,
and is attached to the integument or pa-
rietes of the body, extending down the
middle of the dorsal aspect. It consists of
a thin stratum of minute granules ; clustered
in a ramified form to minute white tubes,
which converge and ultimately unite to form
two oviducts (o, o, Jig. 78). These tubes pro-
ceed from the anterior extremity of the ovary,
diverge, pass on each side of the alimentary
canal, and unite beneath the origins of the nerves
of the body, so as to surround the oesophagus
and these nerves as in a loop. The single tube
(p) formed by the union of the two oviducts
above described, descends, winding round the
alimentary canal in numerous coils, and ter-
minates at the anal extremity of the body. The
single oviduct, besides receiving the ova from
the two tubes (o, o), communicates at its com-
mencement with two elongated pyriform sacs
(tny m), which prepare and pour into the ovi-
duct an opaque white secretion. These bodies,
from their analogy to the impregnating glands
in the Trematoda, I was led to regard (in the
description, published in the Zoological Trans-
actions, of the only individual of this interesting
species that I have hitherto been able to pro-
cure for dissection,) as testes, and the gene-
ration of the Linguatula to be androgynous,
without reciprocal fecundation ; individuals,
however, of the male sex have since been de-
scribed in this species by Miram* and Diesing.

The male Lingiiatula is, as in dioecious
Entozoa generally, much smaller than the
female: the generative apparatus consists of
two winding seminal tubes or testes, and a
single vas deferens, which carries the semen
from the testes by a very narrow tube, and
afterwards grows wider. It communicates
anteriorly with two capillary processes, or
penes, which are connected together at their
origin by a cordiform glandular body, repre-
senting a prostate or vesicula seminalis. The
external orifices of the male apparatus, accord-
ing to Miram, are two in number, and are
situated on the dorsal aspect of the body, just
behind the head.

Diesing, however, describes the male Pen-

* Nova Acta Acad. Naturae Curios, torn. xvii.

Fig. 93.

tastoma as having only a single penis, which
perforates the interspace between the second
and first segments of the body, and protrudes
below and behind the oral aperture.

Much interest attends the consideration of
the reproductive organs of the dioecious En-
tozoa, since they are the first and most simple
forms of the animal kingdom which present
that condition of the generative function. In the
Acanthocephala the structure of the generative
apparatus has been ably elucidated by Cloquet
in the species which commonly infests the
Hog, viz. the Echinorhynchus gigas. The male
organs consist of two testes, two vasa defe-
rentia, which unite together to terminate in a
single vesicula seminalis, and a long penis
gifted with a particular muscular apparatus.
The testes (/, A, fig. 93) are cylindrical
bodies, pointed at both ex-
tremities, of nearly the same
magnitude, but situated one
a little anterior to the other.
The anterior one is attached
by a filamentary process (g)
to the posterior extremity of
the proboscis : the posterior
gland is connected by a
similar filament to the in-
ternal parietes of the body.
The vasa deferent ia (I),
after their union, form seve-
ral irregular dilatations (A:),
which together constitute a
lobulated vesicula seminalis.
This reservoir is filled with
a white grumous fluid like
that which is found in the
testes, and it is embraced
posteriorly by the retractor
muscles of the penis (r, r),
which form a kind of coni-
cal sheath for it.

A small, firm,white, and
apparently glandular body
(q} is situated at the point
of union between the vesi-
cula seminalis and the
penis.

The penis is a straight,
cylindrical, firm, white or-
gan, and in the retracted
state is terminated by a di-
lated portion (o), occupying

the posterior extremity of
^ body> but which d]Sap_

pears when the intromittent
organ is protruded. This
action is produced by the muscles s, s, when
the penis presents the form of a short broad
cone, adhering by the apex to the caudal
extremity of the body: it is retracted by the
muscles r, r, above described.

The female organs consist of two ovaries
and one oviduct. The former are long and
wide cylindrical canals, which of themselves
occupy almost the whole cavity of the body
extending from the proboscis to the tail (h, h,
jig. 83). They are situated, one at the ventral,
the other at the dorsal aspects of the body, arid

"\ t

T

Male organs of gene-
ration, Echinorhyn-
chus gigas.

140

ENTOZOA.

are separated in the greater part of their extent
by a septum : see Jig, 84, f, g, which shows
them in transverse section. They contain a
prodigious quantity of ova, and adhere by
their outer surfaces very firmly to the muscular
parietes of the body.

The dorsal ovary opens into the ventral one
by an oblique valvular aperture about an inch
distant from the extremity of the proboscis,
anterior to which the common cavity extends
forwards between the lateral lemnisci, and
terminates by a conical canal (i, fig. 83), which
is attached to the posterior portion of the pro-
boscis. The two ovaries terminate in a dif-
ferent manner posteriorly, the dorsal one end-
ing in a cul-de-sac, the ventral becoming
c-ontinued in a slender oviduct (/c), which
opens by an extremely minute pore at the
caudal extremity of the body (/). The tissue
of the ovaries is remarkable for its trans-
parency and apparent delicacy, but it pos-
sesses a moderate degree of resistance.

The generative organs in the Nematoidea
are upon the whole more simple than in the
Acanthocephala.

The testis in each of the genera is a single
tube, but differs in its mode and place of ter-
mination, and the modifications of the intro-
mittent part of the male apparatus have
afforded good generic characters.

Genitale masculum, spiculum simplex, is the
phrase employed by Rudolphi in the formula
of the genus Filaria, and this appears to be
founded on an observation made on the Filaria
papillosa, in which he once saw a slender spicu-
lum projecting from near the apex of the tail.
According to the recent observations of Dr.
Leblond,* the male-duct in the Filaria papil-

Fig. 94.

Penis of Ascaris lumbricoides.

* •' Quclques Matcriaux pour scrvir a. 1'Histoirc
des Filaircs et Strongles, 8vo. Paris, 1836."

losa terminates at the anterior extremity of
the body close to the mouth. From this
aperture the slender duct, after a slight con-
tortion, is continued straight down the body to
a dilated elongated sac, which represents the
testis.

In the Ascaris lumbricoides the penis (a, jig.
94) projects from the anterior part of the anus
in the form of a slender, conical, slightly curved
process, at the extremity of which a minute
pore may be observed with the aid of the micro-
scope. The base of the penis (6) communicates
with a seminal reservoir, and is attached to
several muscular fibres, destined for its re-
traction and protrusion : the reservoir is about
an inch in length, and gradually enlarges as it
advances forwards : the^testis or seminal tube
is continued from the middle of the anterior
truncated extremity of the reservoir; it pre-
sents the form of a long, slender, cylindrical,
whitish-coloured tube, extends to the anterior
third of the body, forming numerous convo-
lutions and loops about the intestine, and its
attenuated extremity adheres intimately to the
nutrient vessels of the dorsal region of the
body. The total length of the seminiferous
tube in an ordinary sized Axcaris lumbricoides
is from two feet and a half to three feet. Its
contents, when examined with a high micro-
scopic power, consist of a transparent viscous
fluid, in which float an innumerable quantity
of round white globules, much smaller than
the ova in the corresponding tubes of the
female. In the genus Trichocephalus the fila-
mentary testis is convoluted around the intes-
tine in the enlarged posterior part of the body.
The intromittent organ in the Trichocephalus
dispar is inclosed in a distinct sheath, which
is everted together with the penis, and then
presents the form of an elongated cone (c,
Jig. 69), adhering by its apex to the enlarged
anal extremity of the body, and having the
simple filiform spiculum or penis (d,Jig. 69)
projecting from the middle of its base.

In the Strongylus gigas the bursa or sheath
of the penis terminates the posterior extremity
of the body, and is a cutaneous production,
of a round, enlarged, truncated form, with the
spiculum projecting from its centre, as at B,
Jig. 71. In other species of Strongylus, as in
the Strongylus inflexus, the bursa penis is bifid,
and in the Strongylus armatus it is divided
into four lobes : the obvious functions of these
appendages, as of the lateral alseform cuta-
neous productions which characterize the Phy-
saloptera and Spiroptefx, is to embrace the
vulva of the female, and ensure an effective
intromission and impregnation of the ova.

In the genus Cucullanus, and in most of the
smaller species of Ascaris, the intromittent
organ consists of a double spiculum.

This is also the case in the Syngamus tra-
chealis, the parasitic worm before alluded to as
infesting the trachea of the common fowl, and
occasioning the disease termed the ' Gapes/
In this species the male individual appears as
a branch from the body of the female. The
testis begins near the middle of the oesophagus
by a slender blind extremity, and winds round

ENTOZOA.

141

the gut, as it descends, gradually enlarging, to
the lower part of the intestine, where it sud-
denly contracts and runs down, as a very slender
canal, to near the vulva. It is partly covered
by two long slender bodies of a horny sub-
stance, representing a bifurcate penis.

From this comparison of different genera
of the Nematoidea, it is seen that, althoug
there are many varieties of structure in tl
efferent and copulative part of the male gene-
rative apparatus, the essential or secerning por-
tion uniformly consists of a single tube. A
like uniformity of structure does not obtain in
the essential parts of the female organs : in a
few instances the ovary is single, correspond-
ing to the testis in the male, but in the greater
number of the Nematoid worms it consists of
two filamentary tubes.

The Strongylus gigas is an example of the
more simple structure above alluded to. The
single ovary commences by an obtuse blind
extremity close to the anal extremity of the
body, and is firmly attached to the termination
of the intestine ; it passes first in a straight line
towards the anterior extremity of the body,
and when arrived to within a short distance
from the vulva, is again
Fig. 95. attached to the parietes

of the body, and makes
a sudden turn back-
wards (f,Jig. 95); it
then forms two long
loops about the mid-
dle of the body and
returns again forwards,
suddenly dilating into
an uterus (e), which is
three inches in length,
and from the anterior
extremity of which
a slender cylindrical
tube, or vagina, about
an inch in length, (e,d,
Jig. 95) is continued,
which after forming a
small convolution ter-
minates in the vulva,
at the distance of two
inches from the ante-
rior extremity of the
body. Rudolphi was
uncertain as to the ter-
mination of the ovi-
duct in the Strongylus
gigas, and Professor
Otto, who appears to
have mistaken its blind
commencement for its
termination, believed
that the oviduct opened
into the rectum.

The theory which
had suggested itself to
Rudolphi of the corre-
lation of a simple ovi-
Anterior extremity of the duct in the female with
Strongylus gigas, showing t] spiculum simplex
the commencement of the c , r j r

digeMreand the teriina- °f the male, and of a
tion of the generative tube, double OVlUUCt With

the spiculum duplex, receives additional dis-
proof from the circumstance of the uteri and
oviducts being double in the Strongylus in-
Jie.vus and Strongylus armatus. In the former
species (which infests the bronchial tubes and
pulmonary vessels of the Porpesse, and which
I once found in the right ventricle of the heart
of that animal,) each of the two female tubular
organs may be divided into ovary, oviduct,
and uterus : the ovary is one inch in length,
commences by a point opposite the middle
of the body, and, after slightly enlarging,
abruptly contracts into a capillary duct about
two lines in length, which may be termed the
oviduct, or Fallopian tube, and this opens
into a dilated moniliform uterus three inches
in length ; the divisions here described were
constant in several individuals examined, and
cannot, therefore, be considered to result from
partial contractions. Both tubes are remark-
ably short, presenting none of the convolutions
characteristic of the oviducts of Ascaris and
Filaria, but extend, in a straight line, (with
the exception of the short twisted capillary
communication between the ovaria and uteri,)
to the vulva, which forms a slight projec-
tion below the curved anal extremity of the
body.

The reason of this situation of the vulva
seems to be the fixed condition of the head
of this species of Strongylus. In both sexes
it is commonly imbedded so tightly in a con-
densed portion of the periphery of the lung as
to be with difficulty extracted ; the anal extre-
mity, on the contrary, hangs freely in the
larger branches of the bronchi, where the
coitus, in consequence of the above dispo-
sition of the female organs, may readily take
place.

In the Strongylus armatus the two oviducts
terminate in a single dilated uterus, and the
vulva is situated at the anterior extremity of
the body, close to the mouth.

We find a similar situation of the vulva in
a species of Filaria, about thirty inches in
length, which infests the abdominal cavity of
the Rhea, or American Ostrich. The single
portion of the genital tube continued from the
vulva is one inch and a quarter in length ;
it then divides, and the two oviducts, after
forming several interlaced convolutions in the
middle third of the body, separate ; one ex-
tends to the anal, the other to the oral ex-
tremities of the body, where the capillary
portions of the oviducts respectively com-
mence.

In the Ascaris Lumbricoides the female organs
(Jjg. 96) consist of a vulva, a vagina, a uterus,
which divides into two long tortuous oviducts
gradually diminishing to a capillary tube,
which may be regarded as ovaries. All these
parts are remarkable in the recent animal
for their extreme whiteness. The vulva (</,
Jig. 72,) is situated on the ventral surface of
the body at the junction of the anterior and
middle thirds of the body, which is generally
marked at that part by a slight constriction.
The vagina is a slightly wavy canal five or six
lines in length, which passes beneath the in-

142

ENTOZOA.

Fig. 96.

Female organs,
Ascaris Iwnbricoides.

testine and dilates into the
uterus (k, fig. 96). The
division of this part soon
takes place, and the cornua
extend with an irregularly
wavy course to near the
posterior extremity of the
body, gradually diminish-
ing in size; they are then
reflected forwards and form
numerous, and apparently
inextricable, coils about
the two posterior thirds of
the intestine. Hunter has
successfully unravelled
these convolutions, and
each of the tubes may be
seen in the preparation in
the Hunterian Collection
to measure upwards of four
feet. The generative organs
contained in the female, or
longer branch of the Syn-
gamus trachealis. have a cor-
responding structure with
those of the Nematoidea.
The capillary unbranched
ovary and uterus are double,
as in Ascaris, Spiroptera,
Filaria, and most Stron-
gyli. The vulva is in the
form of a transverse slit,
and is situated at the ante-
rior third of the body, im-
mediately below the attach-
ment of the male branch.

In the Nematoidea the
male individual is always
smaller, and sometimes dis-
proportionately so, than the
female. At the season of
reproduction the anal ex-
tremity of the male is at-
tached to the vulva of the
female by the intromission
of the single or double spi-
culum, and the adhesion of
the surrounding tumid la-
bia; and, as the vulva of
the female is generally si-
tuated at a distance from
either extremity of her body,
the male has the appearance
of a branch or young indi-
vidual sent off by gemma-
tion, but attached at an
acute angle to the body of
the female.*

In the Heterouru andro-
phora of Nitzch (Hersch
and Griiber's Encyclopae-
dic, th. vi. p. 49, and th. ix.

* See Figures of Nematoid
Entozoa in copulation, in
Bremser, Icones Helminthum
tab. iii. fi^. 8. 15. ; and Guiit,
Lehrbuch der Patholog : Ana-
tornie der Haus-Saugethiere,
tab. vi. fig. 35.

taf. 3. f. 7.) the male maintains an habitual con-
nexion with the female, which has a horny pre-
hensile process for tiie purpose of retaining the
male in this position. Here there is no conflu-
ence of the substance of the bodies of the two
sexes ; the individuals are distinct in their su-
perficies as in their internal organization. But
this singular species offers the transitional grade
to that still more extraordinary Entozoon, the
Syngamus trachealisy in which the male is orga-
nically blended by its caudal extremity with the
female, immediately anterior to the slit-shaped
aperture of the vulva, which is situated as usual
near the anterior third of the body. By this
union a kind of hermaphroditism is produced ;
but the male apparatus is furnished with its
own peculiar nutrient system ; and an indivi-
dual animal is constituted distinct in every
respect, save in its terminal confluence, with
the body of the female. This condition of
animal life, which was conceived by Hunter as
within the circle of physiological possibilities,
(see Anim. (Economy, p. 46,) has hitherto been
only exemplified in this single species of Ento-
zoon ; the discovery of the true nature of which
is due to the sagacity and patient research of
Dr. Charles Theodore Von Siebold.

The Entozoa of the parenchymatous class
are chiefly oviparous, those of the cavitary class
for the most part ovoviviparous.

The germinal vesicle has not yet been dis-
covered in the vitelline substance of the ova
of the Acanthocephala, Trematoda, or Ces-
toidea; but it is distinctly discernible in the
ova of the Nematoidea ; I have also observed
and have figured it in the highly organized
ovum of the Lirjguatula ttenioides.

The ova of the Teenies present considerable
varieties of size and form in different species ;
Rudolphi has figured seven forms of these
ova in the Synopsis Entozoorum, (tab. iii.)*
Some are much elongated and pointed at both
extremities, others elliptical: the ova of the
Bothriocep/ialus Latus are of the latter form,
f C,/g 89) ; those of the Ttenia solium are sphe-
rical, as are also the ova of Tteniafiiiformis.
In some species the development of the em-
bryo Tape-worm has been observed to have
distinctly commenced in the undischarged ova,
as in tSie T<enia polymorpha. In dissecting a
Touraco infested by the Tania jUifbrmis, we
found that the segments of the Taania in which
the ova were most developed had been t.e-
tached from the rest of the body, a process
remarkably analogous to that which takes place
in the Lernete and Ent.anostraca, where the
external ovaries are cast off, when charged with
mature ova.

A few of the Trematode Entozoa, as the
Monostoma mutabile, produce the young alive ;
but these have a very different form from the
parent. It would seem that they were des-
tined to pass a transitional state of their ex-
istence in a fluid medium permeated by light,
since two coloured ocelli have been discovered
on the head, and the surface of the body is
beset with locomotive vibratile cilia. f

* Synopsis Entoz. p. 505, pi. iii. fig. 10, 11.
t See Siebold, in Weigmann's Archiv. 1835.

EUTOZOA.

143

The ova of the greater part of the Trcmatoda
are excluded prior to the full development of the
foetus ; they are generally of an oval but some-
times spherical form, and many of <hem singu-
larly resemble the seeds or capsules of certain
mosses, in having a small circular portion of
the outer covering separate from the rest, and
closing the cavity of the egg like a lid.

Nordmann has studied the development of
the young of the Distoma hians, which infest
the intestines of the perch. According to this
excellent observer the foetus raises, in its en-
deavours to slip out of the egg, the small lid,
and writhes about for some time, being still
attached to one point of the egg. In about
six hours it succeeds in freeing itself from
the egg-coverings; and at this period it differs
in every respect from the shape of the parent
animal; the body, which is of a mucous con-
sistence and perfectly transparent, is of an oval
form ; the anterior mouth forms a small square-
shaped projection, and the whole surface
of the body is beset with many longitudinal
rows of short cilia, which are in rapid and
incessant motion, and create a vortex in the
surrounding water, similar to that which the
Polygastric Infusoria produce. The little
animal having its anterior extremity diminish-
ing to a point, is well formed for swimming,
and by means of its vibratile cilia, quickly
darts out of the field of vision when under the
microscope. At the distance of one-third of
the body from the anterior extremity there is
a single coloured eye-speck, from which, when
pressed between glass plates, there escapes
a brilliant blue-coloured pigment. Thus orga-
nized, the young of the intestinal parasite just
described move to and fro in water as if this
were their natural element, and approximate
in form and structure most closely to the Poly-
gastric Infusoria of the genus Param<ecium,
Ehrenb. In this state, doubtless, they are
ejected by the Fish, in the intestines of which
they were originally developed, into the sur-
rounding water, and when again received into the
alimentary canal undergo their metamorphosis,
lose, like the Lerneae and Cirripedes, the organ
of vision which guided the movements of their
young and free life, and grow and procreate
at the expense of the nutrient secretions with
which they are now abundantly provided.

In the Ctctekmntka the young cast their in-
tegument, and would seem in some species,
as the Filaria Medinensis, to undergo a change
in the form and proportions of the extremities
of the body, but they do not possess cilia or
ocelli, as in the Trematoda above-mentioned.

The ova of the Linguatulu are of an oval
form : the germinal vesicle is situated near the
superficies half-way between the two extremi-
ties ; the vitelline membrane is surrounded
with a strong cortical membrane : the develop-
ment of the foetus takes place out of the body.
In the Stnmgyhu g'gas, Strongylus inflerus,
and a species of Tric/iosoma infesting the in-
testines of the Goatsucker, we have found the
foetus completely formed in the ova contained
in the uterus or terminal segment of the gene-
rative tube, while those in the ovary or narrow

commencement of the same part were still occu-
pied with the granular matter of the vitellus.

The mature ova of the Strongylus gigax are
of an elliptical form, and the embryo within
is plainly seen coiled up through the trans-
parent coats of the egg; the resemblance which
these bear to the Trichina when inclosed in
its inner cyst is very striking : the hypothesis
suggested by this resemblance need only be
alluded to for the purpose of exciting the at-
tention of those, who may hereafter meet with
the preceding minute muscular parasite, to the
existence of larger Nematoid Entozoa in other
parts of the body.

Cloquet describes the ova in the beginning
of the ovaries of the Ascaris Lumbricoides as
consisting of rounded linear corpuscles,
pointed at one extremity, thickened at the
other; in the middle of the ovaries they as-
sume an elongated triangular form, and one
of their angles frequently supports a small
spherical eminence; the base of the ovum
adheres to the parietes of the oviduct, the apex
projects into its cavity. In the enlarged canals,
which he terms the cornua of the uterus, the
ova are unattached and of a conoid or irre-
gularly triangular figure. In the uterus itself
they have assumed an ovoid or elliptical form,
are surrounded by a transparent glairy mucus,
and are composed of a transparent cortical
membrane, perfectly smooth on the external
surface, and filled with a transparent fluid, in
which floats a linear embryo, disposed either
in a straight line or coiled up. Cloquet never
observed the young Ascarides excluded from
the egg in the interior of the uterus, and we
equally searched in vain for free embryos in
the generative tubes of the Strongylus and
Oxyurus above-mentioned, although their de-
velopment in regard to form appeared to be
complete in the ovum ; the structure of the
embryo resembles that of the simpler Vibriones,
there being no generative tubes apparent, and
the cavity of the body being occupied by a
granular parenchyma.

With respect to the exclusion of the ova
in these and similar ovo-viviparous Nematoid
Entozoa, it would appear to be very commonly
accompanied with a rupture of the parietes
of the body and of the generative tube. Ru-
dolphi observes, with respect to the Cucullanus,
" Ovula, verme quieto, per intervalla ex vulva
pullulent ; quin eodem disrupto, quod saepe
accidit, ovula vel embryones ex ovariis pro-
lapsis parituque ruptis vi quadam et undatim
protroduntur."

The generation of the Filaria Medinemis is
of the viviparous kind, and the progeny is
countless, — " Filariae nostrae," observes Rudol-
phi, " prole quasi farctae sunt, quod si harum
longitudinem illius vero minutiem spectas,
fcetuura multa millium millia singulis tribuit."
What is most remarkable is, that these em-
bryos are not, as in the Strongylus and the
Nematoid genera above-mentioned, enveloped
in an egg-covering, nor are they included in a
special generative tube, but float freely along
with a granular substance in the common mus-
cular envelope of the cavity of the body.

144

ERECTILE TISSUE.

M. Jacobson,* who has recently published a
description and figures of the young Filaria
Medinensis, compares the body of the mother
to a tube or sheath inhabited by the young
ones ; and, after a careful examination of three
individuals, we have equally failed in detecting
either generative or digestive tubes within
the muscular sac of the body. The external
tunic of the body is a firm subtransparent
elastic integument, which, examined under a
high magnifying power, presents fine trans-
verse striae, occasioned most probably by ad-
herent muscular fibres. Within this tunic
and readily separable from it are the longitu-
dinal muscular fibres, which are arranged in
two fasciculi, separated from each other by two
well-marked intervals on opposite sides of the
body, which are indicated by an impression
(or furrow, as the worm dries by evaporation)
on the exterior surface. When from long
maceration the crisp outer integument has
become separated from the longitudinal mus-
cular bands, these might be mistaken for two
tubes contained loosely within the cavity.

1 believe that these muscular bands are the
tubes fibrineuses, described by Dr. Le Blond f
as the alimentary canal and intestine in the
fragment of Filaria Medinensis^ which he
dissected. In a small Filaria Medinensis,
containing no vermiculi, we have also failed
to discover any distinct tubes for digestion or
generation.

It is interesting to observe that the young
of the Filaria Medinensis do not resemble the
parent in form ; one extremity is obtuse, the
body slightly enlarges for about one-fourth of
its length, then gradually diminishes to within
a third of the opposite extremity, which is
capillary and terminates in the finest point.
The enlarged part of the worm contains a
granular substance, and is coiled upon itself,
and presents a distinct but minute annulation
of the integument : the capillary extremity is
smooth, transparent, and generally straight.
The Trichocephalus dispar closely resembles
in its external form the foetus, if it be such,
of the Filaria Medinensis.

BIBLIOGRAPHY. — Redl, Osservazioni intorno
agli animali viventi che si trovano negli animali
viventi, Firenze, 1684. Block, Abhand. von d.
Erzeugung Eingewerdwurmer. Berl. 1782. Goeze,
Versuch einer Naturgeschichte der Eingewerdwiir-
mer, und Nachtrag dazn. Leipz. 1782-1800. Val-
lisneri, Considerazioni ed esperienze intorno alia
generazione de vermi ordinarj del corpo umano.
Padova, 1782. Werner, Vermium intestinalium,
&c. brevis expositio. Leipz. 1782. Retzius, Lec-
tiones publicae de Vermibus intestinalibus, Holm.
1786. Schrauk, Verzeuhniss der bisherigen hin-
langlich. bekannten Eingeweidw'iirmer, Munch,
1788. Rudolphi, Observ. circa vermes intestinales,

2 fasc. Greifsw. 1793-95. Rudolphi, Entozoorum
s. vermium intestinalium historia naturalis, 2 in 3
vol. Amst. 1808-9. Rudolphi, Entozoorum Synop-
sis, Berl. 1819. Treutler, Obs. pathol. anat. ad
helminthologiam corp. humani. Leipz. 1793. Zeder,
Anleitung zur Naturgeschichte des Eingeweidwiir-

* Nouvelles Annales du Museum d'Histoire Na-
turelle, torn. iii. p. 80, pi. v.

f Quelques Materiaux pour servir a 1'Histoire
des Filaires et des Strongles, 8vo. 1836.

mer. Bamb. 1803. Olfers, De vegetativis ct ani-
matis corporibus in coi'poribus viventibus reperiun-
dis comment. Berl. 1816. Fischer, Bievis Entozo-
orum s. verm, intest. expositio. Vienna?, 1822.
Bremser, Ueber lebende Wiirmer in lebenden Mens-
chen. Wien, 1819; trad, en fran9ais, par MM.
Grundler et de Blainville, Paris, 1825. Bremser,
Icones Helminthorum Systema Rudolphii illus-
trantes, Wien. 1823. Joerdens, Entomologie und
Helminthologie des Mensch. Koerpers. 2Bde. Hof.
1801-02. Lidth de Jeude, Recueil des figures des
Vers intestinaux, Leid. 1829. Cloquet, Anatomie
des Vers intestinaux, Paris, 1824. Creplin, Observ.
de Entozois, Greifesw. 1825-29. Schmalx, De En-
tozoorum systemati nervoso, Leipz. 1827. Ejua,
Tabulae anatomicse Entozoorum, Dresd. 1831. Le
Blond, Quelques materiaux pour servir a 1'histoire
des filaires et des strongles, Paris, 1836. Mehlis,
Obs. Anat. de distomate hepatico et lanceolate,
Gbtting. 1825. Nordmann, Mikrographische Bei-
trage, 2 Bde. Berlin, 1832. Jacobson, in Nouv.
Annales du Museum d'Hist. Nat. torn. iii. Klein,
in Philos. Trans, for 1730. Carlisle, in Trans, of
the Linnean Society, vol. ii. Laennec, in Bulletin
des Sciences de 1'Ecole de Medecine, An xiii.
Home, in Philos. Trans, for 1793; Frisch, in
Miscell. Berolinensia, torn. iii. ; and for further re-
ferences to numerous papers on the natural history
of particular families and species, vide Reusss
Repertorium, &c. Scientis Naturalis, torn. i. Zoo-
logia, &c. Getting, j the first vol. of Rudolphi's
Entozoorum historia naturalis, and Wiegemann'e
Archiv fur Naturgeschichte und Vergleichende
Anatomie.

(R. Owen.)

ERECTILE TISSUE, (tela erectilis ; Fr.
tissu erectile ; Germ, das erectile, oder schwell-
bare Gewebe,) a structure composed prin-
cipally of bloodvessels, intimately interwoven
with nervous filaments. This tissue in its ordi-
nary state is soft, flaccid, and spongy ; but
when influenced by various causes of excite-
ment, whether these consist of stimuli directly
applied, or operating through the medium of
the sensorium, it exhibits the faculty of admit-
ting an influx of blood much greater in quantity
than what is sufficient for its nutrition, and in
virtue of which it suffers a state of turgescence
giving rise to a swollen condition, with more
or less of rigidity and increased sensibility of
the organs into the structure of which it enters,
and which state has been long known by the
name of erection. From the property of under-
going erection peculiar to this tissue, Dupuytren
and Rullier first applied to it the term erectile,
and the propriety of this distinguishing appel-
lation is now very generally admitted by anato-
mical authors.

The erectile tissue is developed in various
degrees in the several parts of the animal
economy in which it occurs; it is abundant
and particularly evident in the corpora caver-
nosa penis, corpus spongiosum urethrse, clitoris,
nymphse, plexus retiformis, the nipples of the
mammary glands, less marked in the red
borders of the lips, &c.; it also enters into the
structure of the papillae of the skin and the
villi of the mucous membranes which possess
the property of becoming erected in the per-
formance of their functions, as is exemplified in
the papillae of the tongue. These consist of the
pulpy terminations of nerves enveloped by this
tissue; in their unexcited state they appear

ERECTILE TISSUE.

145

small, pale, soft, and shrunken; but when
excited to erection, they become increased in
size, stiff, red, and distended with blood, at
the same time that their sensibility i§ remark-
ably exalted. The foregoing remarks apply
equally to the cutaneous papillae, particularly
those on the pulpy extremities of the ringers,
where the sense of touch is developed in its
highest degree of perfection.

Erectile tissue has also been recognised in
the callosities on the buttocks of some of the
quadrumana, in the comb and gills of the
cock, the wattles of the turkey, and in the
tongue of the chamelion.* It is not improbable
that this tissue enters into the structure of the
iris ; and Beclard seems disposed to consider
that it exists in the spleen, as well from the
appearance which that organ presents when a
section of it is made, as from the different
states in which it is found on opening the
bodies of animals ; being sometimes contracted
and corrugated on the surface, and at other
times plump, smooth, and swollen.

In some of the situations above enumerated,
the erectile tissue is enclosed in a fibrous sheath
which limits its extent and determines the form
of the organs in which it occurs ; while in other
situations it is deployed superficially, as in the
tegumentary organs.

It is in the corpora cavernosa penis and
corpus spongiosum urethras, however, that the
erectile tissue has been more especially made
the subject of anatomical and physiological
research ; and the results of the investigations
instituted in these organs have been rather
inferred from analogy than directly proved as
equally applicable to it in- all other situations
in which its existence has been indicated.

According to De Graaf, Ruysch, Duverney,
Boerhaave, Haller, and Bichat, the cavernous
bodies of the penis and urethra consist of a
loose and elastic spongy tissue formed of in-
numerable cells, into which, during erection,
blood is poured from the arteries, and from
which it is afterwards removed by an absorbing
power of the veins. Such an opinion would
accord with the appearances observed by
examining sections of this structure after having
been inflated and dried, but careful examina-
tion of it when previously prepared by injec-
tion, proves the foregoing opinion to be founded
in error.

Vesalius, who appears to have directed his
attention to the particular nature of this struc-
ture in the penis, describes it as composed of
innumerable fasciculi of arteries and veins
closely interwoven, and included in an invest-
ing sheath.

Malpighi considered it as com posed of diver-
ticula or appendices of veins.

Mascagni, who at one time believed in the
existence of cells interposed between the veins
and arteries, in consequence of subsequent
researches abandoned that opinion, and de-
monstrated the fact, that a plexus of veins with
arteries corresponding, but smaller ind less

* On the structure and mechanism of the tongue
of the chamelion, by J. Houston, in Transactions
of the Royal Irish Academy, vol. xv.
VOL. II.

numerous, formed the corpus spongiosum
urethra, glans, and plexus retiformis, and that
the arteries entering this substance terminated
in the commencement of veins.

Mr. Hunter remarked that the corpus spon-
giosum urethrae and glans penis were not
spongy or cellular, but made up of a plexus of
veins, and that this structure is discernible in
the human subject, but much more distinctly
seen in many animals, as the horse. &c.

Subsequent researches respecting the struc-
ture of the penis and clitoris of man, the horse,
elephant, ram, &c. have been instituted by
Duverney, Mascagni, Baron Cuvier, Tiede-
mann, Ribes, Moreschi, Panizza, Beclard,
Weber, &c. and the result has been a con-
firmation of the views developed by Vesalius,
Malpighi, and Hunter.

Moreschi, in particular, has shewn that the
corpora cavernosa penis, corpus spongiosum
urethrae, and glans consist of a congeries of fine
vessels in all animals, whether covered by skin,
hairs, spines, or scales ; and that these vessels,
which are principally veins, are characterized
by their abundance, tenuity, and softness,
which distinguish them from the veins in the
muscles and other parts of the body.

The annexed figure (jig. 97) from Moreschi

Fig. 97.

146

ERECTILE TISSUE.

represents the plexiform arrangement of the
veins apparent on the surface of the glans, and
which empty themselves into the superficial
veins of the penis.

Miiller having more recently investigated
the structure of the penis, has announced the
discovery of two sets of arteries in that organ,
differing from one another in their size, their
mode of termination, and their use ; the first
he calls nourishing twigs (rami nutritii), which
are distributed upon the walls of the veins and
throughout the spongy substance, differing in
no respect from the nutritive arteries of other
parts ; they anastomose with each other freely,
and end in the general capillary network.

The second set of arteries he calls arteria heli-
ciiuE. In order to see these vessels, an injection
of size and vermilion should be thrown into a
separated penis through the arteria profunda :
when the injection has become cold, the
corpora cavernosa should be cut open longitu-
dinally, and that portion of the injection which
has escaped into the cells carefully washed out.
If the tissue of the corpora caveniosa be now
examined at its posterior third with a lens, it
will be seen that, in addition to the nutritious
arteries, there is another class of vessels of
different form, size, and distribution. These
branches are short, being about a line in length
and a fifth of a millimetre in diameter; they
are given off from the larger branches as well
as from the finest twigs of the artery. Although
fine, they are still easily recognised with the
naked eye ; most of them come off at a right
angle, and projecting into the cavities of the
spongy substance, either terminate abruptly or
swell out into a club-like process without again
subdividing. These vessels appear most obvious
and are most easily examined in the penis of
man, to which the following description refers.
These. twigs branch off from place to place,
sometimes alone, and sometimes in little
bundles of from three to ten in number; these,
as well as the former, project constantly into
the cells or venous cavities of the corpora
cavernosa penis. When the arteries thus form
a bundle, they arise by a common stem.
Sometimes such a vessel, whether it proceeds
from the artery as a single branch or as part of
a cluster, divides into two or three parallel
branches, which also either terminate abruptly,
or else swell out near their extremity.

Almost all these arteries have this character,
that they are bent like a horn, so that the end
describes half a circle, or somewhat more.
When such a branch so divides itself, there
are formed doubly bent twigs inclined one to
the other.

Many of these arteries enlarge towards their
end; this enlargement is gradual, and is greatest
at some little distance from the extremity, so
that the end is somewhat conical, terminating
immediately in a rounded point without giving
off any branches. The diameter of these arte-
rial twigs, in their middle, is from one-fifth to
one-sixth of a millimetre : those which branch
off from the trunk of the arteria profunda
penis are no larger than those which arise from
its finest twigs. It is by no means unusual to

Fig. 98.

observe the finest twigs of the arteria profunda
giving off branches of this kind which seem
much thicker than the twig from which they
arose. The annexed figure (fig. 98) (from
Miiller's Archiv.) repre-
sents a portion of the
arteria profunda penis of
man, with its arterise
helicinse somewhat mag-
nified.

These remarkable arte-
ries have a great resem-
blance to the tendrils of
the vine, only that they
are so much shorter in
proportion to their thick-
ness, whence they have
received the name arterise
helicinae. Their termi-
nations may also be com-
pared to a crosier. By a
more minute examination
of these vessels either with the lens or with the
microscope, it will be seen that, although they
at all times project into the venous cavities of
the corpora cavernosa, yet they are not entirely
naked, but are covered with a delicate mem-
brane, which under the microscope appears
granular (Jig. 99).

After a more forcible in-

Fig. 99.

jection this envelope is no
longer visible. When the

arteries form a bundle, the
whole is covered by a slight
gauze-like membrane.

With respect to this in-
vesting membrane, Profes-
sor Miiller appears to con-
sider it as performing an
important part in producing
the phenomena of erection.
These tendril-like arteries have neither on
their surface nor their extremities any openings
discoverable with the aid of the microscope ;
and when the blood, as it is probable, escapes
from them in large masses into the cells of the
corpora cavernosa during erection, it must
either traverse invisible openings, or pass
through small openings which become en-
larged by the dilatation of these arteries. If
the great number of the tendril-like branches
of the arteria profunda be compared with the
very fine nutritious twigs of the same vessel,
it is evident that when the former are filled
they must take up the greater part of the blood
of the arteria profunda; the diameter of the
profunda therefore not only includes its nu-
tritious twigs, but also the tendril-like branches,
which derive their blood from it, yet pro-
bably allow none to pass except during erec-
tion ; therefore the blood in the unerected state
only traverses the nutritive branches and ar-
rives at the commencement of the venous cells
in smaller quantities, while during erection it
probably passes in considerable quantity into
the cells through these tendril-like vessels.

Professor Miiller, after pointing out the dif-
ference between the tendril-shaped vessels and
the looped vessels discovered by Weber in the

EXCRETION.

147

villi of the placenta, observes : our vessels are
simple ; they bend themselves at the end, but
do not return to their trunk as a loop, being
simply blood-containing processes of the ar-
teries which project freely into the cellular
cavities of the veins of the corpora cavernosa.
These vessels are most numerous in the pos-
terior part of the corpora cavernosa ; they
occur but seldom in the middle and anterior
parts : they are also present in the corpus
spongiosum urethra, especially in the bulb;
here also they become less frequent anteriorly,
and as yet they have not been perceived in the
glans. They are much more difficult of detection
in the corpus spongiosum urethrae than in the
corpora cavernosa, where they are very easily
exhibited, especially in the human penis. In
no other animal have they been found so dis-
tinct, or so uniform in their existence as in
man. The greater development of these arteries,
adds Professor Miiller, in the posterior parts of
the organ corresponds with the fact of erection
being always earlier evident there, as if the
blood distributed itself from thence into the
venous cells.

During erection blood is accumulated in
large quantity in the erectile tissue, but the
cause and mechanism of this accumulation are
but imperfectly known. Hebenstreit ascribes
it to a living power, named turgor vitalis,
which exists in different degrees in almost all
the textures of the animal body, but most dis-
tinctly in the erectile tissue. It still remains,
however, to be proved how far erection de-
pends on mechanical pressure affecting the
veins which convey blood from this structure,
and consequent retardation of the venous circu-
lation ; and how far it may depend upon an
increased flow of blood to its arteries accompa-
nied, or perhaps more correctly, occasioned by
an increase of sensibility,* or whether it may not
depend upon the influence of both these
causes combined.

Erectile tissue appears sometimes to be de-
veloped as a morbid production, which has
been described under the names of varicose
tumour, aneurism by anastomosis, naevus ma-
teraus, telangiectasis, &c. Its anatomical cha-
racters are of the same kind as those of the

[* Ii must be obvious that the discovery of the
artericB helicinee by Professor Miiller favours this
theory of erection, as proving the existence of ves-
sels distinct from the ordinary ones, which receive
and transmit the increased supply of blood to the
venous cells. What, in other organs, is effected
by a diminished tonicity in the arteries, and a con-
sequent enlargement of them, ultimately giving
rise to the tortuosity so striking in some cases, is
here effected by means of a very peculiar set of
arterial processes superadded to the ordinary nutri-
tious arteries of the organ. In the pregnant uterus
the increased supply of blood is provided for by the
enlargement and consequent tortuosity of its ordi-
nary arteries ; there are no sinuous veins here to
receive the new supply of blood, and consequently
erection is not present ; but in the case of the
penis this phenomenon occurs in consequence of
the existence of the sinuous veins which constitute
so large a proportion of the corpora cavernosa. It
•will be interesting to inquire whether any similar
or analogous arrangement of arterial processes
exists in other erectile organs.— ED.]

normal erectile tissue ; it varies In size, being
more or less circumscribed, sometimes sur-
rounded by a thin fibrous envelope; presenting
internally an appearance of cells or spongy
cavities, but consisting, in reality, of an in-
extricable congeries of arteries and veins which
communicate by innumerable anastomoses
like capillary vessels, but much larger, espe-
cially the veins. It is difficult to inject it from
the arteries, more easy from the neighbouring
veins, which are sometimes much enlarged.
This alteration most commonly exists in the
substance of the skin, where it sometimes re-
sembles the comb and other analogous parts
of the gallinaceae. The skin of the face, espe-
cially that of the lips, is frequently its seat.
It has been observed in the subcutaneous cel-
lular tissue in masses of various dimensions,
sometimes so large as to occupy an entire limb.
It rarely affects the internal organs ; sometimes
it extends beneath the mucous membrane of
the mouth, mostly in the vicinity of the red
borders of the lips. This production is occa-
sionally affected by a vibratory motion amount-
ing sometimes to a pulsation resembling that
of an aneurismal tumour, which is increased by
all the causes which excite the activity of the
general circulation ; it cannot be properly said
that this structure has the property of under-
going erection. It is often congenital, some-
times it appears to have been produced by
accidental causes; it sometimes remains un-
altered ; but it more usually continues to in-
crease in size until some of its cavities burst,
when haemorrhage of a troublesome description
ensues.

Beclard considers the hasmorrhoidal tumours
which occur round the anus as constituting a
variety of anormal erectile tissue.

BIBLIOGRAPHY. — Vesalius de corp. humani
fabrica, lib. v. cap. xiv. Venet. 1564. De
Graaf Regner, De virorum organis, &c. p. 99 et
seq. Lugd. Bat. 1668. Malpighi Marcelli opera
omnia, torn. ii. p. 221. London, 1686. Ruysch
Frid., Observatio, C. Amstel. 1691. Holier, Ele-
menta, lib. ii. sect. i. § 24, et lib. xxvii. sect. iii.
$ 10. Mascagni, Prodrome della grande anatomia,
Firenze, 1819. Hunter John, On certain parts of
the animal economy, Lond. 1786. Moreschi Alex.
Comment, de urethrae corporis glandisque structura,
Mediolani, 1817. Duvernay, in comment. Petro-
polit. torn. ii. p. 200. Cuvier, Le9ons d'anatomie
comparee, torn. iv. Paris, 1799 — 1805. Tiedemann,
in Journal complementaire, torn. iv. p. 282.
Hebenstreit, G. De turgore vitali in Brera Sylloge,
torn. ii. Duverney, GEuvres anatomiques, torn. ii.
Paris, 1761. Mascagni, P. Hist, vasorum lymphat.
sect. ii. Senis, 1787. Beclard, Anat. generate,
Paris, 1823. Weber, H. E. Allgemeine anatomic,
p. 415. Braunschweig, 1830. Craigie David, M.D.
Elements of general and pathological anatomy,
Edin. 1828. Muller, in Arcliiv fur Physiologie,
Jahr 1835, p. 202. The paper of Professor Muller
has been very ably translated in the London Me-
dical Gazette, No. 423.

(J. Hart.)

EXCRETION.— This term is applied to the
formation of those fluids in the animal economy,
which are destined to no useful purpose in the
system, but are intended to be discharged from
it, and the retention of which is injurious or

L 2

148

EXCRETION.

even fatal. The term used by the older phy-
siologists was excrementitious secretions. Some
general observations may be made on these ex-
cretions, with the view both of stating the pre-
sent extent of our knowledge on this mysterious
subject, and of pointing out the importance of
an arrangement and combination of facts re-
lating to it, which are usually treated, perhaps,
in too unconnected a manner, but the con-
nexion of which is already perceptible, and
can hardly fail to be satisfactorily elucidated
in the progress of physiology.

When we shall have more precise informa-
tion as to the peculiar, and hitherto obscure
principles, which regulate the chemical changes
continually taking place in living bodies, it does
not seem unreasonable to anticipate, that a dis-
covery will be made, connecting the excretions
of the body with the assimilation of the food,
and with the nourishment of the different tex-
tures, a discoveiy which may be equally as
important in illustrating the chemical phenome-
na of the living body, as that of the circulation
was in explaining those changes which come
more immediately under our observation. In
the mean time, we can point out a great deal of
contrivance, connected with the general function
of excretion, and can state what are the general
injurious results, when this contrivance fails of
its intended effect; but we are unable to explain
how the contrivance effects its purpose, or to
point out any general law, by which these in-
jurious results are determined.

I. We may state, in the first place, that the
necessity for some kind of excretion, or dis-
charge of certain matter from the organized
frame, corresponding to the acts of nutrition,
or of reception and assimilation of external
matter, is a law of vital action, applicable to all
organized beings without exception. The uni-
versality of the excretion of carbon, (whether
pure, or in the form of carbonic acid, we need
not now inquire,) has been established by the
inquiries of Mr. Ellis and others, and the poi-
sonous influence of the carbonic acid, in an un-
diluted state, to all living beings, is an equally
general fact. In all animals, which possess
organs of such size and distinctness as to make
their economy matter of observation, other excre-
tions are likewise observed; and in vegetables,
it is not only certain that various excretions,
besides the exhalation of water and of carbonic
acid, take place, but it is even believed by
De Candolle, that all the peculiar products
of vital action, excepting only gum, sugar,
starch, and lignine, (which have nearly the same
elementary composition, and are convertible
into one another,) and, perhaps, fixed oils, are
applied to no useful purpose in the economy,
and are poisonous to the plants in which they
are formed, if taken in by their roots and com-
bined with their sap ; so that, although often
long retained in individual portions of the
plants, they all possess the essential characters
of excretions.* And it appears to be well ascer-
tained by the observations of De Candolle and
of Macaire, that at least great part of the proper

* Physiol. Veget. p. 217.

juices of vegetables, which descend chiefly by
their bark, and are expelled into the soil, are
destined to excretion only, and are noxious to
plants of the same species, or even of the same
families, if growing in that soil (although often
useful to the growth of plants of different fami-
lies) ; and this principle has been happily ap-
plied by the former author to explain the neces-
sity of rotation of crops of different natural
families, to prevent deterioration of the produce.*

As this necessity of excretion appears to be
so general an accompaniment of the vital action
of all organized beings, it seems obvious that
there must be some general law, which deter-
mines the noxious quality of these products of
that action, and imposes the necessity of their
expulsion. Yet it is certain that the chemi-
cal elements which pass off in the excretions,
are the same which are found in the textures of
the animal body, and in the nourishment, which
is essential to animal life.

It would appear, therefore, that the noxious
property belongs to certain combinations only
of these elements, which are formed in the course
of the chemical changes in living beings, and
which, when once formed, must either be ex-
pelled from the body, or else laid up in cells
appropriated for the purpose, (as in the case of
the resins and volatile oils in vegetables, and of
the bile in the gall-bladder in animals,) and kept
out of the mass of the nourishing fluid.

There is one general fact, on which much
stress has been justly laid by Dr. Prout, which
is confirmed by M. Raspail, and which may,
perhaps, be concerned in determining the
noxious qualities of certain compounds, in liv-
ing beings, viz. that although the elements
which enter into the composition of organized
bodies, readily combine, in other circumstances,
so as to form crystals, yet the peculiar combi-
nations which they form in all the textures
which are essential constituents of those organic
structures are never crystalline. When a crystal
occurs in an organized body, according to Dr.
Prout,-f- it is always either the result of disease,
or of some artificial process, or it is part of an
excretion, separated from the nourishing fluid
and from the useful textures.! Every one of
these textures contains, even in its minutest
particles, saline and earthy, as well as animal
or vegetable matter ;§ but the combinations are
always so arranged, by the powers of life, that
these saline and earthy particles are always dif-
fused through membranes, fibres, or cells, never
concentrated in crystals. On the other hand,
the elements constituting the peculiar matters of
the excretions are generally in such a state of
combination as readily to assume the crystalline
form, either alone, or in the simplest farther
combinations of which they are susceptible ;
and it seems possible, that this circumstance
may be part at least of the cause which necessi-
tates their expulsion. This is only matter of

* Ibid. p. 249, and p. 1496.

f Lectures in Medical Gazette, vol. viii.

j "Jamaisje n'ai ape^u/' says Raspail, " de
cristaux dans le sein d'une cellule vivante et d'ac-
croisement," Raspail, Chimie Organique, § 1378.

§ Ibid. § 1390.

EXCRETION.

149

speculation, but that some such general prin-
ciple determines the incompatibility of the mat-
ters of the excretions with the life of the struc-
tures in which they are formed, can hardly be
doubted.

II. Although the necessity of various excre-
tions is obvious, there is a difficulty, both in
the case of animals and vegetables, in fixing on
those products of vital action which come exclu-
sively under this denomination ; and it appears
certain, that some of the organs of excretion
(such as the lungs) are at the same time de-
stined to other purposes, particularly absorption ;
and even that part of certain excreted fluids
(such as the bile) is employed likewise in the
work of assimilation. But it is certain that the
lungs or gills, the skin, the intestines, and the
kidneys, are the outlets for excreted matters in
all vertebrated animals.

1. There can be no doubt that the watery
vapour and carbonic acid which are exhaled
from the lungs, are strictly excretions, although
it is still doubted by some physiologists, whe-
ther the latter substance is truly exhaled, or
rather formed at the lungs; on the latter sup-
position we should say, that the excretions of
the lungs are water and carbon. It appears
certain, from some experiments of Dr. Cordon,
that no animal or saline matter escapes by this
outlet. The total amount of loss by this excretion
in twenty-four hours, in a middle-sized man, has
been stated by Lavoisier and Seguin as aver-
aging about fifteen ounces ; and it must be re-
membered, that as we have good evidence of
very considerable absorption at the lungs, the
whole quantity of matter excreted must consi-
derably exceed this weight. Indeed, Mr. Dai-
ton estimates the exhalation of watery vapour
only from the lungs at twenty-four ounces in
the day. Some have estimated the quantity of
carbon alone escaping in this way in the day at
eleven ounces; but this estimate is probably
exaggerated. It seems to be ascertained by the
experiments of Dr. Edwards, of Despretz, and
Collard de Martigny, that there is at times an
obvious exhalation of azote by the lungs; and
Dr. Edwards expresses an opinion that there
is probably, at all times, both an exhalation
and absorption of that gas, but that these
processes in general nearly compensate one
another. According to Dr. Prout's views, re-
cently, though briefly, announced, we may, per-
haps, state the source and cause of the forma-
tion of the carbonic acid, and assign the use of
the excretion of the water, which escapes by the
lungs, with more precision. He supposes the
acid to be evolved in the course of' the circula-
tion, by that " process of reduction," by which
the gelatin of the animal textures is formed
from the albumen of the blood ; and the water
to be given off chiefly from the weak albuminous
matters of the chyle, and to be an essential part
of the " process of completion," by which this
is converted into the strong albumen of the
blood*

2. The excretion by the skin is chiefly

* See Bridgewater Treatise, p. 524.

watery vapour; the escape of carbon, or carbonic
acid, by this outlet appears to be to a very small
amount, and to be very variable. In the sen-
sible perspiration or sweat there is an excess of
lactic acid, a small quantity of the same animal
and saline matters as are contained in the serum
of the blood, and a little oily or fatty matter,
probably from the sebaceous glands ; the whole
loss by this excretion in the human adult has
been stated as averaging about thirty ounces in
the day, but is evidently liable to very great
variety. Many experiments prove that there is
much less compensating absorption by this tex-
ture than by the lungs.

3. The excretions by the bowels are, properly
speaking, only those parts of the alvine evacua-
tions, which are secreted within the body itself,
and mixed with the residue of the food. It is
probable that part of the secretions from all
parts of the primae viae are thus excreted, but
the only one of which it has been ascertained
that it is, in part at least, destined necessarily
for excretion, is the bile. It is certain that the
peculiar animal matter of this secretion, (re-
garded by some as of pretty simple and by
others as of very complicated composition) is
never found in the healthy state in the lacteal
vessels or thoracic duct — that it is found in full
quantity along with the residue of the aliments
in the lower intestines, — that it is increased in
quantity when the excretion of urine is sup-
pressed in animals by extirpation of the kid-
neys ; and again, that when this secretion is sup-
pressed, the urine is increased and altered ; and
we can therefore have no difficulty about regard-
ing this part of the bile as strictly an excretion,
notwithstanding that we have good evidence,
that at least the alkali of the bile is of use in
the digestion and assimilation of the food. Of
the quantity of matter strictly excreted from the
intestines in the day it must of course be very
difficult to judge. The chemical elements that
escape in the biliary matter must be chiefly
carbon and hydrogen.

4. The urine is the most complex of the ex-
cretions, particularly as to saline impregnation,
containing not only the salts which are detected
in the blood, but a portion of every earthy and
saline matter that can be found in any part of
the body, besides the peculiar and highly azo-
tised animal matters, lithic acid and urea. The
average quantity of urine passed in twenty-four
hours may be about forty ounces, but is very
liable to variation, particularly by temperature,
being generally greater, as the excretion by the
skin is less. The quantity of solid matter,
animal, earthy, and saline, that passes off in
this way has been stated at about fifteen drachms
on an average, and is evidently much less liable to
change, the density of urine, in the healthy state,
always diminishing as its quantity increases, and
vice versa. The milk, and the semen, although
destined to no useful office in the system in
which they are formed, are rather to be called
recrementitious secretions than excretions. Yet
the former has this property in common with
excretions, that its retention within the body,
when the conditions of its formation exist, i&

150

EXCRETION.

hurtful. The menstrual discharge may be
regarded as strictly an excretion, though one
which is required only in the human species
and for a limited time.

Berzelius stated several distinctions, which
he thought important, between the excVemen-
titious and recrementitious secretions in the
animal body, particularly that the former are
always acid, that each of them contains more
than one animal matter, and that their salts are
more numerous and varied than those in the
blood, while the latter have an excess of alkali
from the same saline ingredients as the serum
of the blood, and each contains only a single
animal principle, substituted for the albumen
of the serum. But these distinctions are cer-
tainly inapplicable in several instances, and the
only one of them which appears to be a general
fact, is the more complex saline impregnation
of the excreted fluids.

III. It is unnecessary to dwell on the well-
known injurious effects, on the animal ceconomy,
of the suppression of any of these excretions.
It may, indeed, reasonably be doubted, whether
the rapidly fatal effects of obstructing the ex-
posure of the blood to the air at the lungs are
owing to the retention of carbon, or carbonic
acid ; it seems much more probable that the
cause which stops the circulation at the lungs
in asphyxia, is the suspension of the absorption
of free oxygen into the blood, rather than the
suspension of the evolution of carbon or car-
bonic acid. But even if the circulation could
be maintained, after the exposure of the blood to
the air is suspended, we know that the carbonic
acid which we have good reason to believe
would soon be in excess in the blood, would
then act as a narcotic poison. Of the effects of
suspension of the excretion by the skin we can-
not speak with certainty, because that is a case
which probably hardly ever occurs ; and if it
were to occur, the lungs and kidneys would
probably act as perfect succedanea. But it is
worthy of notice that at a time when the skin is
known to be nearly unfit for its usual functions
— during the desquamation that succeeds exan-
thematous diseases, and especially scarlatina, —
the lungs and the kidneys, on which an unusual
burden may thereby be supposed to be thrown,
are remarkably prone to disease. The effect of
suppression of the excretion of urine (i. e. of
ischuria renalis), whether occurring as a disease
in man, or produced by extirpation of the kid-
neys in animals, is uniformly more or less of
febrile symptoms quickly followed by coma
and death ; and in these circumstances it is
now known, that the urea may be detected in
the blood. A variety of morbid affections, and
particularly an affection of the nervous system
marked by inaptitude for muscular or mental
exertion, always follows the obstruction of the
excretion of bile, and absorption of bile into
the blood constituting jaundice.

There are a few cases of intense jaundice
which terminate in coma and death as rapidly
as the ischuria renalis does, and with as little
morbid appearance in the brain to explain this
kind of fatal termination ; and in several such

cases the remarkable phenomenon has been
observed after death, that the bile-ducts have
been pervious and empty* It is obvious, that
it is this last circumstance only, that can
make a case of jaundice analogous to cases
of the ischuria renalis. If it shall appear
to be a general fact, that the cases of jaundice
presenting this remarkable appearance on
dissection are those which terminate with
unusual rapidity in the way of coma, the
analogy will appear to be complete ; and when
such cases are compared with those, much
more frequently occurring, where the excretion
of bile is only obstructed, not suppressed, and
where months frequently elapse without any
bad symptom occurring, — it appears a reason-
able conjecture, that the retention in the blood
of matters destined for excretion, is more
rapidly and certainly injurious than the re-
absorption of matters "which have been excreted
from the blood at their ordinary outlet, but not
expelled from the body.

Although there is still much obscurity in
regard to the intention of the menstrual dis-
charge, yet it may be stated as a general fact,
that the suppression of this evacuation is more
frequently followed byinjurious effects (particu-
larly affections of the nervous system, or vica-
rious haemorrhage) than the stopping of an equal
amount of haemorrhage, going on equally
slowly, would be ; so that the general principle
applicable to other excretions is exemplified
here likewise.

IV. The next question in regard to the ex-
cretions is, in what manner they are effected ;
and on this question, although we must profess
ignorance in the last result, yet it is instructive
to observe, what seems now to be well ascer-
tained, that the large size, and apparently com-
plex structure, of several of the organs of excre-
tion, appear to be no part of the contrivance
for the formation of these fluids from the blood.

It is stated by Cuvier, as the result of a
general review of the structure of glandular
organs in different classes of animals, that pro-
ducts very nearly resembling each other, and
evidently answering the same ends, are formed
in organs where the structure, and the disposi-
tion of vessels are very various ; and again,
that substances the most widely different are
formed in organs that are in these respects ex-
tremely similar ;f and that this should be the case
will not appear surprising when we consider
the result of the most minute and accurate
observations on the ultimate structure even of
those secreting organs, which form substances
the most dissimilar to the general nourishing
fluid, either of animals or vegetables. " Chaque
cellule de la structure vegetale," says De
Candolle, " peut etre consideree comme une
vesicule organique et vivante, qui est entouree,
ou de cavites dans lesquelles abordent des
liquides, ou de cellules remplies elles-memes de

* See Marsh in Dublin Hospital Reports, vol. iii.
Two cases of exactly the same description have oc-
curred within these few years in the Edinburgh
Clinical wards.

t Lc9ons d'Anat. Comp. t. v. p. 214.

EXCRETION.

151

liquides. Cette vesicule, par sa vitalite' propre,
absorbe une partie du fluide qui 1'entoure;
ce fluide est ou de 1'eau presque pure, et alors
elle eh est simplement impregnee et lubrifiee ;
ou de 1'eau plus ou moins chargee de cette
matiere gommeuse, elaboree dans les feuilles,
et d'autres matieres alimentaires qui peuvent
se trouver portees avec la seve dans les diverses
parties. La vesicule qui Va absorbee lui J'ait
subir une action determinee d'apres sa propre
nature, et cette action modifie les materiaux
contenus dans la cellule, de maniere a en faire,
ou 1'une des matieres communes que nous
avons considerees, ou 1'une des matieres que
nous aurons bientot a examiner, telles que
les huiles volatiles, les resines, &c. Certains
vaisseaux analogues a la nature des cellules
jouent le meme role sous ce rapport. Les
matieres ainsi localement elaborees peuvent, ou
rester dans les cellules ou les vaisseaux qui
leur ont donne naissance, ou s'extravaser au
dehors et donner lieu, soit a des excretions, soit
a des transports des matieres d'une partie a
1'autre dutissu."*

The description given by Dutrochet of the
act of secretion as it may almost be detected
in the glands of the lower classes of animals,
is exactly similar. " Entre les vesicules qui
composent le tissu organique des animaux
rampent les vaisseaux sanguins,chezles animaux
a circulation : ces vesicules sont appliquees
sur les parois des vaisseaux ; et il est certain
que la cavite des vesicules ne communique
point immediatement avec la cavite des vais-
seaux, puisque le meme fluide n'existe point
dans leurs cavites. Ce fait est tres facile a
verifier, en examinant au microscope le tissu
d'un organe secretive chez uu mollusque gas-
teropode, celui de la foie par example : on
voit toutes les vesicules de cet organe remplies
par la bile, que Ton distingue a sa couleur,
tandisque les vaisseaux sanguins qui cotoient
ces vesicules n'ont que la diaphaniete que leur
donne 1'etat incolore du sang qui les remplit.
Ainsi, les vaisseaux sanguins n 'existent que
comme des moyens d'irrigation pour les vesi-
cules qu'ils cotoient, et ce n'est peut-etre que
par filtration que le fluide sanguin penetre, en
si modifiant, jusque dans ces vesicules elemen-
taires. Le systeme sanguin, considere dans
son entier, forme une cavite sans issue, dans
laquelle rien ne peut entrer, et de laquelle rien
ne peut sortir, autrement que par filtration."-^

Any one who is acquainted with the elabo-
rate " Vasorum Lymphaticorum Historia" of
Mascagni, will recognize the perfect accordance
of this statement with the result of his careful
and minute investigation of the structure of the
secreting organs in the higher animals. J

We may consider, then, the act of secretion,
'•' en derniere analyse," as consisting simply in

* Physiol. Vegetale, p. 215.

t L'agent immediat du mouvement vital devoile.
&c. p. 192.

$ It must not be considered as ascertained, that
the files or tracks of globules of blood seen under
the microscope, and usually called capillaries,
have really, in all animals, and all parts of these,
vascular coats. It seems pretty certain, that in

the passage of certain portions of a compound
fluid through a thin living membrane, and the
exclusion of others ; or, according to the for-
tunate expression of Dutrochet, as a chemical
filtration. " All that is necessary for any
kind of secretion in a living animal," says Mr.
Mayo, " is a vascular membrane, and all the
arrangements of the glands appear to be merely
contrivances for conveniently packing a great
extent of such a surface in a small compass."
And if we are asked, to what cause we can
ascribe this escape of certain matters from the
circulating fluid through one portion of mem-
brane, and of others through another, we can
only answer, in the words of this last author,
that it depends on the exercise of certain " vital
affinities" peculiar to the living state, and the
existence of which will always be an ultimate
fact in Physiology, although we may attain to
a knowledge of the laws according to which
they operate.

V. One principle may already be laid down,
almost with certainty, as to the exercise of these
powers in the present instance, viz. that the
peculiar matters characterizing the excretions
are not actually formed from the blood at the
parts where they appear, but only separated
from the blood at these parts, — their formation,
if not actually completed, having been at least
considerably advanced, in the blood itself
which reaches these parts. Of this we are
well assured, chiefly by the following facts.

1 . The experiments already mentioned, first
made by Prevost and Dumas, have proved
that within a short time after the extirpation of
the kidneys in animals, urea may be detected
in the blood, showing clearly that the existence
of these glands is not necessary to the forma-
tion of this very peculiar excrementitious matter,
and giving us reason to conjecture that the
office of the kidneys is, not to form the urea,
but to attract it out of the blood as fast as it is
formed there. The same existence of urea in
the blood has been ascertained in the human
body, both in cases of diseased kidneys, when
the excretion there was much impeded, and in
cases of malignant cholera, when the excretion
was suppressed. The cases of rapidly fatal jaun-
dice already mentioned, where the bile-ducts were
pervious and empty, would seem to have been
cases where the peculiar matter of the bile has
been in like manner formed in the blood,
without finding the usual vent at the liver.
And it will appear under the head of Respira-
tion, particularly from the experiments of Dr.
Edwards, and of Collard de Martigny, that
there is good reason to believe the carbonic acid
of expired air to be formed in the course of the
circulation, and only exchanged for oxygen at
the lungs.

2. There are various instances in disease, of
substances generally found in the secretions of
certain glands only, being deposited in situa-
tions quite unusual, and where no texture
similar to these glands exists ; e. g. cholesterine,

many cases they are only lines or membranes, or
channels in a solid parenchyma ; but still the obser-
vation in the text applies strictly to the escape of
any particles of the circulating fluid from them.

152

EXCRETION.

which in the natural state is found only in the
bile, has been found deposited in diseased
structures in the brain, kidneys, pelvis, scro-
tum, &c. ; and lithic acid, naturally existing
only in the urine, is deposited in cases of chalk-
stone in the textures immediately surrounding
the joints of the fingers and toes. It seems to
be nearly in like manner that purulent matter,
when mixed in unusual quantity with the
blood, as by inflammation of a vein, is fre-
quently deposited in individual parts of the
body, with little or none of the usual sym-
ptoms, or of the other accompaniments, of in-
flammation at these parts.

3. There are a considerable Dumber of cases
recorded on unexceptionable evidence, where
excretions have passed off per aliena cola, i. e.
by organs which in the natural state yield no
such products, and the structure of which is
widely different from that of the glands where
they are usually secreted. This has been most
frequently observed of the milk and of the
urine, and of the latter, both in cases where
the secretion at the kidneys had been sup-

rsed, and in cases where its discharge by
urinary passages has been obstructed, so
as to occasion its re-absorption. In both cases
it is obvious that the peculiar matter of this
excretion must have been first mixed generally
with the blood, and then deposited in indivi-
dual parts of the system, widely different as well
as distant from those where it usually appears.

In cases of this kind collected by Haller,*
the vicarious discharge of urine is stated to
have occurred from the skin, from the stomach,
from the intestines, and from the nipples ; and
in cases recorded by Dr. Arnold and Dr. Sen-
ter in America, it is stated to have been passed by
vomiting, by stool, from the nose and from the
mammae, as well as other parts .f Both in
cases given by Haller, and in one recorded in
Magendie's Journal de Physiologic, (vol. vii.)
milk is stated to have been evacuated in quan-
tity from pustules that formed on the thigh ;
and among the former are instances of its hav-
ing passed off" from the salivary glands, the
kidneys, and the uterus. Such statements
were formerly considered as fabulous, but since
the facts already mentioned (and particularly
the appearance of urea in the blood after ex-
tirpation of the kidneys) have been ascertained,
this scepticism seems no longer reasonable.

It must be here observed, that the healthy
blood is easily shown to contain in itself mat-
ters more nearly akin to all the solid textures
and to the other secreted fluids of the body,
than to the bile and the urine ; and hence, if
we are satisfied that the elaboration of these
latter fluids is effected in the blood itself, and
does not essentially require any special action
of the organs in which they usually appear,
there can be little hesitation about extending
this inference to other acts of secretion and
to nutrition. It appears, therefore, at least
highly probable, that the whole processes of as-
similation and elaboration of the fluids in the

* Elem. Phys. lib. vii. ch. 1.

t London Med. and Phys. Journal, 1828.

living body are carried on, as other chemical
changes on fluids are, in the interior of these
fluids themselves, and that the solids of the
body are concerned in these changes only in
two ways : Jirst, by securing the complete sub-
division and intimate intermixture of the fluids
necessary to their chemical changes ; and second-
ly, by determining the parts of the body where
peculiar matters, already existing in the blood,
shall be deposited from it, or attracted out of it.

VI. We may next enquire, what is the most
probable original source of the matters which
are thrown out of the body in the way of ex-
cretion. As it is generally believed, and on
strong grounds, that the solid textures, as well
as prepared fluids of the body, are liable to
continual decay and renovation, it has long been
the general belief, that the materials for the ex-
cretions are supplied chiefly from those sub-
stances which have formed part of the textures,
and, after fulfilling their office there, have been
taken back into the circulation with a view to
their discharge from the body. And it has
been conjectured, certainly with much probabi-
lity, by Berzelius and by Autenrieth, that the
animal matters thus mixed with the blood on
their way to the excretories, are distinguishable
from the albuminous or nutritious parts of the
blood, by their solubility both in hot and cold
water, and constitute the animal matter of the
serosity, or uncoagulable animal matter of the
blood. This is supported by the observation,
that, when the kidneys are extirpated, this
part of the blood is first observed to increase
in amount, and afterwards it is here that the
urea is detected.* And the connexion of
the excretions with absorption from all parts of
the body seems farther illustrated by the pheno-
mena of diabetes, which may be held to be the
disease in which there is the strongest evidence
of increased absorption in all parts of the body,
from the rapid digestion, the rapid recurrence
of thirst after drinking, the dryness of the sur-
face, and the progressive emaciation notwith-
standing the excessive amount of ingesta ; and
in which the quantity of the urine is often ten
times, and the solid contents of the urine often
twenty times, the average quantity in health.f

But it should not be too hastily concluded,
that all the solid constituents of the animal body
are liable to continual absorption and renova-
tion. The permanence of coloured marks on
the skin, noticed by Magendie, is sufficient
evidence, that, in some of the textures, any such
change must go on very slowly ; and some of
the best observers doubt whether any such pro-
cess of alternate deposition and absorption takes
place in vegetables, in which, nevertheless, as
we have seen, excretion is a necessary process.

* Prevost et Dumas in Ann. de Chimie, t. xxiii.
p. 97.

t The change of nature of the animal part of
this solid matter, (viz. the disappearance of part of
the urea, and substitution of an excessive quantity
of sugar,) is evidently connected with the singular
fact ascertained by Dr. Prout, that sugar differs
from urea simply in containing no azote, and a dou-
ble quantity of carbon and oxygen : a discovery
which will, probably, acquire a greatly increased
importance in the progress of organic chemistry.

EXCRETION.

153

Dr. Prout has lately stated strong reasons for
thinking, that great part of the contents of the
lymphatic vessels are not excrementitious, but
destined for useful purposes in the animal eco-
nomy; remarking particularly on the way in
which hybernating animals appear to be nou-
rished by absorption of their own fat*

And it is obviously possible, that the excre-
tions may be required to purify the blood of
matters taken in from without, or evolved in
the course of the circulation and its abundant
changes, as well as to purify it of what has
been absorbed from the system itself. Now
that we know, that great part of the ingesta into
the stomach are taken up by the veins, and pass
through the liver on their way to the heart ; and,
likewise, that the venous blood is the chief
source of the excretions of bile, it seems pro-
bable, that one important use of this excretion
is, to subject a part of the ingesta to a second
filtration, or rejection of part of their ingre-
dients, subsidiary to that which they undergo in
the primae viae. This may also be probably one
principal reason why the great mass of the chyle,
and other products of absorption in the body,
should be mixed with the blood just before its
concentration at the heart, and subsequent dif-
fusion through the lungs ; and thus participate
in a purification, by the rejection of water and
carbonic acid, before they are applied to the
purposes of nutrition. We know, that in birds,
reptiles, and fishes, there is a venous circulation
similar to that of the vena portac, through the
substance of the kidneys, of most of the blood
coming from the lower half of the body ; a
part of the ingredients of that blood will, there-
fore, be evolved with the urine; and, in the
case of the reptiles, it has been lately ascertained,
that this venous blood receives, before entering
the kidneys, the contents of numerous and large
lymphatics .-)-

At all events, if we are right in supposing,
that, in the higher animals, all the great chemi-
cal changes which are wrought on the blood,
even the formation of the excretions, are effected
during its circulation in the bloodvessels them-
selves, we can thereby acquire a general notion
of the intention of several contrivances, the use
of which is otherwise very obscure. We can
understand, that the object of the concentration
of the blood at the heart may be not merely
mechanical, but, partly, also chemical ; and we
can see the intention of the heart being so ad-
mirably adapted, by the articulated structure of
its internal surfaces, not only to receive and
propel, but also most effectually to intermix, all
the component particles of the blood, both be-
fore and after its exposure to the air ; the most
perfect illustration of which power of the heart
is afforded by the effect it produces on any com-
pressible and elastic fluid which is received in
a mass of any considerable volume into its cavi-
ties, and which is necessarily subdivided into so
many minute globules, and compressed in so
many directions, that it cannot escape from the
heart, and.so stops the circulation.

* Bridgewater Treatise, p. 515, et seq.
t M tiller, in Phil. Transactions, 1833.

Again, when we attend to the manner in
which substances foreign to the circulation are
absorbed into it, whether from the system itself,
or from without, we see a great deal of contri-
vance, evidently adapted, and probably intended,
to secure the raosi gradual introduction, and the
most perfect intermixture possible, and to allow
the escape of certain parts of the compound
fluid formed. Thus of the contents of the
primae vise, part are absorbed into the veins, and
sent through the capillaries of the liver and
those of the lungs, (both admitting of excretion,)
before they are admitted into the arteries.
What is taken up by the lacteals has already
undergone much elaboration by living fluids ;
this portion passes through the mesenteric glands,
and is, probably, so far intermixed with the
blood there, and partly received into the veins
passing from them to the liver;* and the rest is
mixed with much matter flowing from other
parts of the system by the lymphatics; and,
according to the views of Dr. Proutf as to the
nature of absorption, is so far assimilated by
this mixture also, before it is poured into the
great veins in the state of chyle, to undergo the
thorough agitation at both sides of the heart,
and to participate in the changes at the lungs.
What is absorbed from other parts of the body
seems to be partly taken up by the veins, partly
also by lymphatics which immediately convey
it into adjacent veins; the remainder passes
through lymphatic glands, and is there pretty
certainly subjected to an intermixture and an
interchange of particles with blood; after
which it has necessarily much further admix-
ture, and two thorough agitations at the heart,
as well as the exposure at the lungs, to undergo,
before arriving at the left side of the heart.

In those of the vertebrated animals which
have no lymphatic glands, the thorough inter-
mixture of the fluids contained in the lymphatic
vessels is provided for by numerous plexuses,!
and, in the case of reptiles, by distinct lympha-
tic hearts communicating with veins ;§ and we
are sure, that much of the matters absorbed in
these animals, whether by veins or lymphatics,
passes through the capillaries of the kidneys or
liver, as well as the lungs, before reaching the
arteries.

When we see so much contrivance, evidently
adapted for giving every facility to the gradual
operation of the vital affinities subsisting among
the constituents of the blood, before it reaches
the scene of any of the acts of nutrition, secre-
tion, or excretion, we cannot be surprised to
find, that these acts themselves should appear
to be so simple as the observations already
quoted would seem to indicate.

It must be admitted, that if we consider these
contrivances in the higher animals as important
agents in the elaboration of the blood, and con-
sequent formation of the textures and prepared
fluids of the body, there is a difficulty in under-
standing how these objects can be accomplished

* Tiedemann et Gmelin, Recherches, &c.
f Bfidgewater Treatise, ubi supra.
| Cuvier, Lemons, &c. t. iv. p. 98.
$ M tiller, ubi supra.

154

EXTREMITY.

in the lowest classes, particularly the insects
and zoophyta, where the nourishment of various
textures, and formation of secretions and excre-
tions, has been thought to be merely in the way
of imbibition from a central cavity.* But it is to
be observed, that in several of these tribes, in
insects, and even in the infusory animals, recent
observations have disclosed a much more com-
plex apparatus for the movement of the fluids,
than was previously suspected. And, in regard
to the lowest zoophyta, it may be said in general,
that if there is little apparent provision for the
elaboration of the fluids, there is also little
occasion for \l,— first, because there is little
variety of textures to be nourished, and
secondly, because the simplicity of their
structure is such, that all the particles of their
nourishing fluid, — admitted into a central
cavity, flowing thence towards their surface, and
acted on by the air at all parts of that surface, —
are similarly situate in regard to all the agents
by which they can be affected, and must be
equally fitted for the changes which the vital
affinities there acting on them can produce, so
that the same necessity for gradual intermixture,
and repeated agitation, of heterogeneous mate-
rials, does not probably exist in them, as in
the animals of more complex structure. The
analogy of their economy, therefore, is not a
serious objection to the inference we have
drawn from so many other facts, as to the
numerous changes which are wrought in the
blood of the higher animals, while circulating
in the vessels, and as to the function of excre-
tion being a necessary accompaniment of the
assimilation of aliment, and nutrition of tex-
tures, even independently of their renovation by
processes of ultimate deposition and absorption .
(W.P.Alison.)

EXTREMITY, (in human anatomy), mem-
brum,artus; Gr. //,eXo?, xwAov ; Fr. extremity,
membre ; Germ. Gliedmassen ; Ital. membra.
This term is used to denote certain appendages
most manifest in the vertebrated classes of
animals, employed as instruments of prehen-
sion, or support, or motion, also occasionally
employed for other purposes sufficiently in-
dicated by the habits of the animal. In fa-
miliar language we apply the word, limb,
synonymously, and the superior and inferior
limbs of man, or the anterior and posterior ones
of the Mammiferous Quadrupeds, are the best
examples by which we can illustrate our de-
finition. When these appendages exist in their
complete number, i. e. four, they are distin-
guished either by the appellatives already
mentioned, anterior and posterior, or superior
and inferior, or more precisely pectoral, and
pelvic or ventral, or again atlantal and sacral.

In Fishes we find that in most instances the
anterior limbs (pectoral fins) are larger than the
posterior (ventral fins) : and sometimes the
posterior are absent altogether, as in the com-
mon eel. In Fishes we look for the simplest
form of the skeleton of the more highly de-
veloped limbs in Man and Mammalia: and

* Cuvier, Lemons, &c. 27.

here we find, more or less obviously in differ-
ent instances, the same elements which sub-
sequently appear in a more distinct and com-
plete form. Thus, in the case of the Lophius
piscatorius, we find very distinctly the scapula
and clavicle forming the bond of connection
of the other bones of the limb to the trunk.
We can also recognize the radius and ulna,
what seems to be a very rudimentary humerus,
and the bones of the carpus, as well as the
phalanges, which generally greatly exceed in
number any arrangement that is to be found
in the higher classes. The ventral fins, how-
ever, the analogues of the posterior extremities,
are not so developed : while bones analogous to
the phalanges of the feet are found in it, we meet
no trace of the femur, tibia, or fibula.

In all the other Vertebrata we find the an-
terior and posterior extremities developed on
a plan similar to that in man, with such vari-
ations as the manner of life of the animal
requires. We must, however, notice an excep-
tion in the case of serpents and Cetacea. In
the former there are no limbs, or at least the
merest trace of them ; in the latter the pos-
terior are absent, although the anterior exhibit
very perfectly all the elements of the human
upper extremity.

We propose to devote the present article to
the detail of the descriptive anatomy of the
osseous system of the extremities in Man,
in whom, by reason of his erect attitude, the
terms superior and inferior are substituted for
anterior and posterior, as applied to the ex-
tremities of the lower animals.

Superior extremity. — The superior extremity
is connected to the trunk through the medium
of two bones, which, as being intimately con-
nected with the motions of the limb, first de-
mand attention. These bones are the clavicle
and scapula, and are commonly called the
bones of the shoulder.

Clavicle (from clavis, a key;) collar-bone ;
syn. ligula, jugulum, osfurcale; Germ. Schlus-
selbein. This bone is situated at the upper
and anterior part of the thorax, and forms the
anterior part of the shoulder: its direction is
from within outwards, so that its external end,
which is articulated with the scapula, is pos-
terior, and on a plane superior to its internal
end, which is articulated with the sternum.
It thus constitutes the key to the bony arch
formed at the shoulder, and hence its integrity
is especially necessary to the integrity of the
motions of the shoulder.

The clavicle is a long bone, cylindrical, and
so curved as to resemble the italic f placed
horizontally. Its internal extremity is thick
and rounded, while its external one is flat-
tened ; of its two curves one is internal, with
its convexity directed forwards ; the other ex-
ternal, with its convexity directed backwards.

The internal extremity, also called sternal,
is formed by a gradual expansion of the shaft
of the bone, which, however, still preserves
the general cylindrical form, but is flattened a.
little on its superior surface : in size this ex-
ceeds all other parts of the bone. The inner
surface of this extremity of the clavicle is

EXTREMITY.

155

destined for articulation with the sternum, and
accordingly we find on it a considerable arti-
cular facet, which is convex from above down-
wards, and concave from before backwards.
The outline of this surface is triangular, and
each angle is easily distinguishable by the
degree of its prominence : thus, one angle is
situated anteriorly and inferiorly, it is the least
prominent ; a second is posterior and inferior,
it is the most prominent; and the third is su-
perior, and may easily be felt under the inte-
guments in the different motions of the bone.

The external or acromial end of the clavicle
is at once distinguished by its flattened appear-
ance; it is flattened on its superior and in-
ferior surfaces. At its extremity we find an
elliptical articular surface adapted to a similar
one upon the acromion process ; this surface is
nearly plane, its long axis is directed horizon-
tally from before backwards.

The body or shaft of the bone presents se-
veral points deserving of notice. The superior
surface is smooth and rounded, expanding to-
wards the sternal end, where it affords attach-
ment to the clavicular portion of the sterno-
mastoid muscle. It expands likewise towards
the acromial end, but loses the cylindrical
form and becomes flattened : the central part
is the most contracted and the most cylindrical;
here the bone is almost subcutaneous, being co-
vered only by the common integument, some
fibres of the platysma, and crossed by the
supra-clavicular filaments from the cervical
plexus of nerves.

On the inferior surface of the clavicle we
notice towards its sternal end a rough surface
for the insertion of the costo-clavicular or rhom-
boid ligament : external to this and extending
outwards is a superficial excavation along the
inferior surface of the bone, which lodges the
subclavius muscle. This groove terminates at
the commencement of the external fourth of
the bone, where we notice a rough and promi-
nent surface for the insertion of the coraco-cla-
vicular or conoid and trapezoid ligaments; in
the articulated skeleton this surface corresponds
to the root of the coracoid process, immediately
over which it lies. On the inferior surface,
near its middle, is the orifice of the canal for
the transmission of the nutritious artery, the
direction of which is outwards.

The anterior edge is thicker and more rounded
towards the inner than towards the outer end,
where it partakes of the general flattened ap-
pearance of the bone at that part; in the former
situation it affords attachment to the pectoral is
major muscle — in the latter to the deltoid. The
two internal thirds of this edge are convex, its
external third is concave.

The posterior edge is smooth and thin upon
its two internal thirds, thicker and rougher at
its external third, where the trapezius muscle is
inserted into it; in the former situation this
edge is convex, in the latter it is concave. The
relations of the clavicle in this situation are in-
teresting : it forms the anterior boundary of a
space somewhat triangular in form, through
which a communication is formed between the
axilla and the neck. The posterior boundary

of this opening is formed by the superior
border of the scapula, and the internal by the
inferior vertebra of the cervical region of the
spine, while the first rib constitutes a sort of
floor, over which pass the various vessels, nerves,
and other parts which enter the cavity of the
axilla. The anterior third of the first rib passes
beneath the sternal end of the clavicle, but its
two posterior thirds lie on a plane superior to
it. Consequently we find that the cone of the
pleura passes up behind this end of the clavicle
so as to be on a level with it, hence the so-
noriety elicited by percussion of the clavicle,
and hence likewise the possibility in many
instances, where embonpoint does not interfere,
of hearing the respiratory murmur in the supra-
clavicular region.

The great importance of the clavicle in the
motions of the upper extremity is rendered
abundantly evident by observing how com-
pletely synchronous are its movements with
even the slightest change of position in the arm.
But this is illustrated in a more striking man-
ner by reference to the comparative anatomy of
this bone. Those animals only possess a well-
developed clavicle whose habits of life require
extensive and varied movements of the shoul-
der. Where the anterior extremity is employed
merely as an instrument of progressive motion
on a plane surface, we have no clavicle ; hence
this bone is absent from the skeletons of Pa-
chydermata, Ruminantia, Solipeda, and the mo-
tions of the shoulders are only such as are
required for the flexion and extension of the
limb. In the Carnivora, where there is a slight
increase in the range of motion of the anterior
extremities, a rudimentary clavicle exists, and in
this class we observe that the size of the bone in
the different orders bears a direct relation to the
extent of motion enjoyed by the limb. Thus
it is smallest in the Dogs and largest in the
Cats; in these animals it has no attachment to
either the sternum or the scapula, but is enclosed
in the flesh, and does not occupy much more
than half the space between the two bones last
named. " But, however imperfect," says Sir
C. Bell, " it marks a correspondence in the bones
of the shoulder to those of the arm and paw, and
the extent of the motion enjoyed. When the
bear stands up, we perceive, by his ungainly
attitude and the motion of his paws, that there
must be a wide difference in the bones of his
upper extremity from those of the ruminant or
solipede. He can take the keeper's hat from
his head and hold it; he can hug an animal to
death. The ant-bear especially, as he is defi-
cient in teeth, possesses extraordinary powers
of hugging with his great paws; and, although
harmless in disposition, he can squeeze his
enemy the jaguar to death. These actions and
the power of climbing result from the structure
of the shoulder, or from possessing a collar-bone
however imperfect."*

In those Mammalia that dig and burrow in
the ground, or whose anterior extremities are
so modified as to aid them in flight, or who
are skilful in seizing upon and holding objects

* Bridgewater Treatise, p. 48.

156

EXTREMITY.

with their paws, the clavicle is fully developed,
and extends the whole way from the scapula to
the sternum. Thus in the Rodentia this bone
is very perfect, as, for example, the Squirrel,
the Beaver, the Rabbit, the Rat, &c. The Bat
affords an example of a very strong and long
clavicle, as also the Mole and the Hedgehog
among the Insectivora.

Among the Edentata those tribes possess a
clavicle whose habits are fossorial, as the Ant-
eater, the Armadillos, and even the Gigantic
Megatherium, in which animal, however, the
clavicle presented the peculiarity of being arti-
culated with the first rib instead of with the
sternum. In the Quadrumana the clavicles are
strong and curved as in the human subject.

In Birds, the bone which is analogous to
the clavicle presents similar variations in its
developement, according to the range of motion
required in the anterior extremity, or in other
words, in proportion to the extent to which the
powers of flight are enjoyed. Thus, in some
these bones are anchylosed along the mesial
line, and constitute the furculum ; in others
they are cartilaginous internally; and in others
they do not reach the sternum.*

In women the clavicle is in general less curved
than in men ; the diminution in the incurvation
is most manifest in the external portion . Accord-
ing to Cruveilhier, the clavicles are often une-
qually developed in the same individual accord-
ing as one limb is more used than the other, and
sometimes the difference is sufficiently obvious
to enable one to ascertain from the relative size
of the clavicles, whether the individual is right
or left-handed.

Structure. — The clavicle contains a conside-
rable proportion of compact tissue in its shaft,
and a cylindrical medullary canal ; at the ex-
tremities the compact tissue greatly diminishes,
and is replaced by the reticular, which likewise
fills up the bone and obliterates the medullary
cavity.

Developement. — A strong argument as to the
great importance of this bone to the motions of
the shoulder, is derived from its precocious de-
velopement ; for although the cartilaginous nidus
of the vertebrae as well as that of the ribs appear
before that of the clavicle, yet the latter bone
begins to ossify sooner and is completed more
rapidly than any other bone in the body, ex-
cepting perhaps the lower jaw, which some-
times takes the precedence in the process of
ossification. It is remarkable too for the diver-
sity in its proportional size, which it presents
at different periods; thus, according to Meckel,
about the middle of the second month of
pregnancy, the clavicle is four times longer
than the humerus or femur, and it is not until
the fourth month that the humerus exceeds it
in length. The clavicle has but one primitive
point of ossification : a supplementary point is
developed under the form of a very thin lamella
at the anterior part of the sternal extremity.f

Scapula, scapulum, omoplata, (upo^ hume-
rus, wAaru?, latus.) Fr. omoplate; Germ, das
Schulterblatt. — This bone forms the posterior

* See Avfcs, p. 285, vol. i.

t Cruveilhier, Anat. Desc. t. i. p. 219.

and principal portion of the shoulder; it is
placed on the posterior and outer part of the
thorax, and occupies a space which extends from
the second to the seventh rib.

The scapula is very thin in the greatest part
of its extent, quite papyraceous in some places.
It is triangular in form, and anatomists com-
monly describe its sides or borders, its angles,
and its surfaces.

The borders, or costte, of the scapula are
three in number, and are named according to
the position they occupy or the relation
they bear: thus there are the superior border
or cervical, the posterior or vertebral, and the
anterior or axillary. The cervical border (also
called the coracoid) is the shortest, being some-
what less than a fourth of the length of the
vertebral border; it is connected posteriorly
with the vertebral at an angle the apex of which
is rounded off; it is slightly concave, and the bone
for some way below it is very thin, and the bor-
der itself is acute. Anteriorly it terminates in a
notch which is bounded in front by one root of the
coracoid process, (incisura semilunaris, lunulay
coracoid notch.) This notch is converted into
a foramen by a ligament which is often ossi-
fied, and thus the suprascapular nerve, which
is lodged in the notch, is separated from the
artery of the same name, which passes over
the ligament. The extent, therefore, of the
cervical border is from the posterior superior
angle to this notch. The levator anguli sca-
pulae and the omo-hyoid muscles are attached
to this border.

The vertebral border, also called the base of
the scapula, is the longest, being in an ave-
rage-sized bone from seven to eight inches in
length ; it is sharp in its whole extent, which
is limited above by the posterior superior angle,
and below by the inferior angle. At the junc-
tion of the superior fourth with the remaining
portion there is an inclined surface, triangular
in form, the base confounded with the margin
of the bone, the apex continued to the spine.
This surface is smooth, and the ascending
fibres of the trapezius muscle glide over it.
To that part of this edge, which is above the
surface, the levator anguli scapulae is attached,
and below it the rhomboidei.

The anterior or axillary border is limited
above by the glenoid cavity, and below by the
inferior angle of the scapula. It is much
thicker than either of the others, and its thick-
ness increases towards its upper extremity,
where, close to the glenoid cavity, there is a
rough surface which gives attachment to the long
head of the triceps muscle ; inferior to this, the
edge affords insertion to the teres minor muscle,
and still lower down to the teres major.

The superior and posterior angle is formed
by the junction of the cervical and vertebral bor-
ders; it is a little less than a right angle, and is
chiefly remarkable for affording insertion to the
levator anguli scapulae muscle. The inferior
angle, formed by the union of the axillary and
vertebral borders, is very acute; the bone here is
very thick and spongy ; part of the latissimus
dorsi glides over this angle, and sometimes
some of its fibres are inserted into it. It is

EXTREMITY.

157

only tliis portion of the muscle which separates
this part of the scapula from the common inte-
guments, and to this superficial position is at-
tributed the more frequent occurrence of frac-
tures from direct violence in this than in any
other portion of the bone.

The angle between the cervical and axillary
borders is truncated, and presents many points
of great interest. We here notice an articular
concavity, destined to contribute to the for-
mation of the shoulder-joint, commonly known
under the name of the glenoid cavity, (sinus
articularis.J This cavity, which is a very
superficial one, is oval; the long axis of the
oval being vertical in its direction, the acute
extremity of the oval is situated superiorly,
and here the edge of the bone is cut and
rounded off towards the posterior part, where
is inserted the tendon of the biceps. The
cavity is surrounded by a thick lip of bone,
to which in the recent state the fibro-cartilage,
called glenoid ligament, is applied. At the
internal or anterior part of this border, is a
notch for the passage of the tendon of the sub-
scapularis muscle. The aspect of the glenoid
cavity when the scapula is quiescent is outwards
and slightly upwards and forwards. This cavity
is connected with the rest of the bone by a thick
but contracted portion denominated the neck
of the scapula. The neck of the scapula is
surmounted by a remarkable curved process,
called the coracoid process, (xopa.%, corvus.)
This process, well compared to a semiflexed
finger, is directed forwards and outwards, it is
connected to the scapula by a thick portion,
which seems to arise by two roots, one posterior,
thick and rough, lying immediately in front
of the notch in the cervical border, the other
anterior and thin, and connected with the apex
of the glenoid cavity. The concave surface
of the coracoid process is directed downwards
and outwards, and in the recent state projects
over the upper and internal part of the shoul-
der-joint : its convex surface is rough, and has
inserted into it the ligaments by which the
clavicle is tied to it. The coracoid process
affords attachment by its internal edge to the
pectoralis minor muscle ; to its outer edge is
affixed the ligament which, with the acromion
process, completes the osseo-ligamentous arch
over the shoulder-joint, and by its summit it
gives insertion to the short head of the biceps
and to the coraco-brachialis.

It remains only to examine the surfaces of
this bone. The anterior surface forms in the
greatest part of its extent a shallow fossa, fossa
subscapularis, which is limited above and be-
hind by the superior and posterior margins of
the bone, and in front by a smooth and rounded
ridge, which extends from the glenoid cavity
to the inferior angle. This fossa is frequently
intersected in various directions by bony ridges.
Cruveilhier remarks, that in a well-formed per-
son, this surface ought to be exactly adapted
to the thorax; but when the chest is contracted,
as in phthisical patients, the scapula not par-
ticipating to a proportionate extent in the con-
traction, there follows such a change of re-
lation that the scapulae become very prominent

behind, and are in some degree detached from
the ribs like wings, whence the expression
scapula alata, applied to the projection of the
shoulders in phthisical patients. The whole
fossa has lodged in and inserted into it the
subscapularis muscle, whence its name. At
the superior posterior angle and the inferior
one, are rough surfaces into which are inserted
the superior and inferior fibres of the serratus
magnus muscle.

The posterior surface is remarkable for its
division into two portions by a large process
which projects from it nearly horizontally back-
wards and slightly upwards. This process, called
the spine of the scapula, is fixed to the bone
at the line of union of its superior and mid-
dle thirds ; it commences at the triangular
surface already noticed at the termination of
the superior fourth of the vertebral border of
the scapula, thence it proceeds outwards, in-
clining a little upwards, and just where the
neck of the scapula is united with the rest
of the bone, this spine ceases to be connected
with the scapula, and is continued outwards in
a slightly arched form, as a broad and flattened
process, denominated the acromion process,
(<zx£o?, summus, up,o^, humerus.} The spine
presents posteriorly a thick and rough edgey
which by its superior border gives attachment
to the trapezius muscle, and by its inferior to
the deltoid, the intervening space being covered
by the aponeurotic expansion which connects
the muscles last-named. The superior surface
of the spine looks nearly directly upwards ; it
is concave, and contributes to form the fossa
supra-spinata. The inferior surface, on the
other hand, forming part of the fossa supra-
spinata, is convex anteriorly and slightly con-
cave posteriorly, and looks downwards and
backwards ; on each surface we observe a large
nutritious foramen. The posterior edge of the
spine is quite subcutaneous, and the physician
often finds it desirable to practise percussion
upon it.

Above the spine of the scapula is the fossa
supra-spinata, which lodges the muscle of the
same name, formed in front by the scapula,
behind by the spine, both surfaces being
slightly concave. Below the spine is the fossa
supra-spinata much larger than the preceding,
slightly convex, except towards its anterior
part. This fossa is formed by the scapula
below and the inferior surface of the spine
above ; it is limited in front by a ridge which
proceeds downwards and backwards, from the
glenoid cavity to the inferior angle, and bounds
behind a surface which gives attachment to
the teres major and minor muscles. Into this
ridge itself is inserted a fibrous fascia, which
separates the attachment of the last-named
muscles from the fossa infra-spinata and the
insertion of the muscle of the same name. The
two fossae, thus separated by the spine, com-
municate through a channel formed on the
posterior part of the neck of the scapula and
bounded behind by the spine ; through this
channel pass the arterial and nervous ramifica-
tions from the superior to the inferior fossa.
The acromion process is evidently continu-

158

EXTREMITY.

ous with the posterior thick edge of the spine
of the scapula, and viewed from above ap-
pears to be merely an expansion of it. The
narrowest part of the process is where it seems
to spring from the spine, forming a sort of
pedicle. Its posterior surface is convex, rough,
covered with fibrous tissue in the recent state ;
its aspect is upwards and backwards. Here
the process is quite subcutaneous as the pos-
terior part of the spine of the scapula. The
anterior surface is concave, smooth, looks
downwards and forwards to the posterior and
superior part of the shoulder-joint. The
posterior or inferior edge of the process con-
tinuous with the corresponding edge of the
spine of the scapula forms a curve, convex
downwards and outwards, and terminates
in the pointed extremity or apex of the pro-
cess; all this edge affords attachment to the
deltoid muscle. The superior edge is con-
cave ; near the apex we observe upon it a
plane oval articular surface to which the acromial
extremity of the clavicle is articulated ; into
this edge the trapezius muscle is inserted.
The apex of the acromion, which is imme-
diately in front of the articular surface for the
clavicle, gives insertion to the apex of the liga-
ment, whose base is attached to the outer edge
of the coracoid process.

The scapula is connected to the trunk through
its articulation with the clavicle, but chiefly
through the intervention of muscles, so that
muscles are inserted into all its edges, and its
surfaces are " cushioned with muscles." It is,
then, as might be anticipated, a very moveable
bone, and its motions consist in more or less
extensive revolutions round an axis through its
centre. This bone, then, being the medium
of connexion between the pectoral extremity
and the trunk, it is evident that the great move-
ments of the former must depend upon the
movements produced in the scapula by the
muscles which pass to it from the trunk ; more-
over, when some of these muscles fix the
scapula, it becomes the point whence the others
act in producing the motions of the ribs. The
scapula, then, is an essential element in the
upper extremity, and it exists wherever we
find that limb in a perfectly developed state,
but it experiences various modifications in
position and shape according to the uses to
which the upper extremity is applied. In
quadrupeds the position of the scapula is more
forwards and on the side of the chest, for in
them the anterior extremity is employed as an
instrument of support. It is interesting to
observe the variation in the aspect of the glenoid
cavity, according to the oblique or upright
position of the scapula, indicating whether
the pectoral extremities are used chiefly as
instruments of support or as instruments of
prehension, &c. When freedom and rapidity
of motion are required conjoined with strength,
we find the scapula placed obliquely over the
ribs, and a corresponding obliquity between
the humerus and scapula. " In the horse, as
in most quadrupeds, the speed results from
the strength of the loins and hinder extremities,
for it is the muscles there which propel the

animal. But were the anterior extremities
joined to the trunk firmly and by bone, they
could not withstand the shock from the descent
of the whole weight thrown forwards; even
though they were as powerful as the posterior
extremities they would suffer fracture or dis-
location. We cannot but admire, therefore, the
provision in all quadrupeds whose speed is
great, and whose spring is extensive, that, from
the structure of their bones, they have an
elastic resistance by which the shock of descend-
ing is diminished.

" If we observe the bones of the anterior
extremity in the horse, we shall see that the
scapula is oblique to the chest, the humerus
oblique to the scapula, and the bones of the
fore-arm at an angle with the humerus. Were
these bones connected together in a straight
line, end to end, the shock of alighting would
be conveyed through a solid column, and the
bones of the foot or the joints would suffer
from the concussion. When the rider is thrown
forwards on his hands, and more certainly when
he is pitched on his shoulder, the collar-bone
is broken, because in man this bone forms a
link of connexion between the shoulder and
the trunk, so as to receive the whole shock ;
and the same would happen in the horse, the
stag, and all quadrupeds of great strength and
swiftness, were not the scapula sustained by
muscles and not by bone, and did not the
bones recoil and fold up."

" The horse-jockey runs his hand down the
horse's neck in a knowing way and says, * this
horse has got a heavy shoulder, he is a slow
horse/ He is right, but he does not under-
stand the matter; it is not possible that the
shoulder can be too much loaded with muscle,
for muscle is the source of motion and bestows
power. What the jockey feels and forms his
judgement on is the abrupt transition from the
neck to the shoulder, which, in a horse for the
turf, ought to be a smooth undulating surface.
This abruptness or prominence of the shoulder
is a consequence of the upright position of the
scapula; the sloping and light shoulder results
from its obliquity. An upright shoulder is the
mark of a stumbling horse — it does not revolve
easily to throw forward the foot."*

A comparison between the skeleton of the
anterior extremity in the elephant and in one
of the stag kind illustrates how the oblique
position of the scapula is favourable to rapidity
of motion, while the upright position is that
most calculated for supporting weight. In the
elephant the glenoid cavity of the scapula is
placed vertically over the head of the humerus,
and all the other component parts of the limb
are similarly disposed, so as to form a complete
pillar of support for the trunk. Hence the
attitude of standing in the elephant requires
but slight muscular effort, and in this position
he is in such complete repose as often to obtain
sleep. In this animal, then, the angle between
the scapula and humerus is nearly obliterated,
but in the stag it approaches closely to a right
angle, the scapula is oblique to the ribs, and

* Sir Charles Bell, Bridgewater Treatise.

EXTREMITY.

159

the humerus to the scapula. The rule seems
to be that where the pectoral extremity is chiefly
a pillar of support, the aspect of the glenoid
cavity is nearly vertically downwards. If free-
dom and rapidity of motion be required in
addition to strength as a member of support,
the trunk being lighter, the scapula is oblique,
and consequently the glenoid cavity looks
downwards and forwards ; or if the limb be
not used to support the trunk, then the aspect
of the glenoid cavity is no longer downwards
but outwards, as in man.

Structure. — The greatest part of the scapula
is composed of very thin almost papyraceous
compact substance ; but its processes, and the
enlargements at its edges and angles, contain
reticular tissue.

Developement . — This bone is developed by
six points of ossification ; one for the body,
and five supplementary ones, viz. one for the
coracoid process, two for the acromion, one
for the posterior border of the bone, and one
for its inferior angle. The ossification of the
body commences about the second month, and
the spine appears in the third month as a
growth from the posterior surface of the scapula.

The union of the several epiphyses is not
completed till late, and it is not until after the
fifteenth year that the ossification is finished.

The bones of the upper extremity, properly
so called, are the humerus, radius, ulna, and
bones of the hand.

Humerus, (os brachii; Fr. Vos du bras;
Germ, das Oberarmbein). This is the longest
bone of the upper extremity; it is situated
between the scapula and forearm, being, as it
were, suspended by muscle and ligament from
the former.

Like all long bones, the humerus consists
of a shaft and two extremities. The superior
extremity is formed by a smooth and rounded
convexity, rather less than half a sphere; a
slight depression in, or constriction of, the
bone, most manifest above, marks the limit of
this articular eminence. The eminence is
called the head of the humerus ; the constric-
tion indicates what is denominated the anato-
mical neck of the bone, being that portion
which connects the head to the shaft, and
analogous to the more developed neck of the
thigh-bone. The axis of the neck is but a
continuation of that of the head, and passes in
a direction from within outwards and down-
wards, forming an obtuse angle with the axis
of the shaft. The head of the humerus is
entirely covered by articular cartilage, and arti-
culates with the glenoid cavity of the scapula,
to which, however, it obviously does not at all
correspond in dimensions.

The inferior part of the anatomical neck of
the humerus is very slightly marked, and is
continued in a smooth declivity slightly con-
cave from above downwards, into the shaft of
the bone. Its superior part is more distinct,
and the depth of the groove here seems in a
great degree owing to the prominence of two
bony protuberances, one situated anteriorly,
called the lesser tuberosity, and the other pos-
teriorly, denominated the greater tuberosity.

The lesser tuberosity of the humerus (tuber-
culum minus) is somewhat conical in shape,
and inferiorly it ends in a smooth, rounded
bony ridge (spina tuberculi minoris), which
extends downwards and inwards, gradually
diminishing in prominence till it is lost in the
shaft of the bone at the inner part of its ante-
rior surface. The lesser tuberosity gives in-
sertion to the tendon of the subscapularis
muscle, and the ridge or spine last described
forms the anterior and internal boundary of the
bicipital groove.

The greater tuberosity (tuberculum majus,
externum s. posterius) forms a considerable
prominence on the upper and outer part of
the humerus, being the most external part in
that situation and easily to be felt under the
integuments. Superiorly the constriction cor-
responding to the anatomical neck separates it
from the head of the humerus ; inferiorly it is
continued into and gradually lost in the shaft
of the bone at its outer part. A very distinct
and prominent ridge ( spina tuberculi majoris)
is continued from its anterior extremity down-
wards and inclining very slightly inwards,
which terminates about the middle of the an-
terior surface of the bone, just internal to the
deltoid ridge. This ridge is most prominent
but smooth in its upper third, in its inferior
two-thirds it is less prominent but rough; it
forms the posterior boundary of the bicipital
groove. On the greater tuberosity three dis-
tinct surfaces are marked, to the anterior of
which the supra-spinatus muscle is attached,
to the middle the infra-spinatus, and to the
posterior the teres minor.

The bicipital groove commences above be-
tween the two tuberosities, and passes down-
wards and slightly inwards, bounded before
and behind by the spines which proceed from
those tubercles. This groove, very distinct at
its commencement, ceases to be so a little
above the termination of the superior third ;
in the recent state it is lined by the tendinous
expansion of the latissimus dorsi and teres
major muscles, and lodges the tendon of the
biceps muscle, whence its name.

From the anatomical neck the bone gra-
dually tapers down and becomes more cylin-
drical in its form ; this upper portion is, for the
convenience of description, distinguished by
the name of surgical neck of the humerus.
The middle third of the shaft of the bone
is prismatic in form ; the external spine
which commences at the greater tuberosity
is continued down, forming a prominent
ridge all down the front of the bone to the
termination of its flattened inferior third. The
outer part of the middle third of the humerus
is remarkable for the rough surface into which
the deltoid muscle is inserted, the deltoid ridge,
situated nearer the upper than the lower part
of this portion, and directed downwards and
very slightly forwards. The inner part of the
middle third presents a smooth, flattened, and
inclined surface, which is continued down in
this form to within a very short distance of the
inferior extremity of the bone. The posterior
surface is rounded and very smooth.

160

EXTREMITY.

At the junction of the middle and inferior
thirds we notice a very slight and superficial
groove passing downwards and inwards, and
very much resembling what one would ima-
gine might be produced by an attempt to twist
Die bone while yet in a yielding condition, the
inferior third having been twisted inwards and
the two superior thirds outwards. This groove
indicates the spiral course from above down-
wards and from without inwards of the musculo-
spiral or radial nerve. Below this groove is the
inferior third of the humerus, the anatomical
characters of which are very distinct from those
of the remaining parts of the bone. A pro-
minent and rounded ridge, continuous with
that already noticed in connexion with the
greater tuberosity, passes vertically down in
front of it; from each side of this ridge a
smooth surface inclines backwards, forming
an inclined plane on each side of it, the ex-
ternal being larger and more distinct than the
internal.

The posterior surface of the upper part of
this portion is flat and very smooth. As the
bone descends it expands considerably late-
rally, so as to present in front a broad surface
slightly convex from side to side, bounded on
either side by prominent edges, continued from
the edges of the inclined planes above de-
scribed. Each edge terminates in a pro-
minence, the inner one being the largest ; the
inner edge itself being thicker, more pro-
minent, and describing a slight curve as it
descends. The posterior surface is limited
below by a deep depression, to be further de-
scribed hereafter. Thus, by its gradual expan-
sion laterally, the inferior portion of the hu-
merus, being about one fifth of the entire
length of the bone, has a triangular figure, the
base being formed by the inferior articular ex-
tremity of the bone.

The whole shaft of the humerus is com-
pletely clothed with muscle. We have already
indicated the place of insertion of the deltoid
muscle on the outer surface of the bone ; all
that portion of the outer and anterior surface
below the deltoid ridge, and for a little way
on each side of its inferior extremity, is co-
vered by the brachiaeus anticus muscle. In-
ternal to the bicipital groove, on the inner
surface of the humerus, about its middle, the
ooraco-brachialis muscle is inserted. The ex-
ternal edge below the spiral groove affords
attachment to the brachiaeus anticus, supinator
longus, extensor carpi radialis longior, and the
triceps muscles.

The internal edge below the insertion of
the coraco-brachialis has the brachiaeus anticus
and triceps muscles inserted into it, and both
edges afford insertion to intermuscular apo-
neuroses, which separate the muscles con-
nected with the anterior from those on the
posterior part of the bone. The posterior sur-
face is completely covered by the triceps mus-
cle, excepting in the line which corresponds
to the groove already referred to, in which the
radial nerve and musculo-spiral artery pass.

The foramen for the nutritious artery is found
upon the internal surface at the inferior ex-

tremity of its middle third ; the direction of
the canal is downwards ; sometimes this fora-
men exists upon the external, or upon the in-
ternal surface.

The inferior extremity of the humerus is
terminated by an articular cylinder, which pro-
jects into a plane anterior to that of the shaft
of the bone, (processus cubitalis). This cy-
linder is placed transversely, but in transverse
extent it falls short of the widest part of the
inferior third of the humerus. Various de-
pressions and elevations are marked upon the
surface of this cylinder. Proceeding from
without inwards, we notice a convexity or
rounded head, limited externally by the mar-
gin of the cylinder and internally by a groove,
which passes in a curved direction from before
backwards, the concavity of the curve corres-
ponding to the rounded head. This head is
properly denominated the external condyle of
the humerus ; it articulates with a cavity on
the head of the radius ; the anatomist should
notice that the axis of this head passes in a
direction downwards and forwards. On the
anterior surface of the humerus immediately
above this head, we observe a slight and very
superficial depression which receives the edge
or lip of the cavity of the radius, when the
forearm is in a state of complete flexion.
Internal to the groove which bounds the con-
dyle on the inner side, we have a pulley-like
surface, which is destined for articulation with
the ulna. The concavity which forms the cen-
tral part of this pulley is deep, but deeper and
wider behind than before; its anterior ex-
tremity terminates in communicating with an
oval depression on the anterior surface of the
bone (fovea anterior minor), which in flexion
of the forearm receives the anterior projecting
angle of the coronoid process of the ulna;
the posterior extremity terminates in a similar
depression, (fovea posterior v. sinus maximus,)
but a much deeper one, and of greater dimen-
sions generally, occupying, in short, nearly the
whole posterior surface of the bone; this de-
pression receives the olecranon process of the
ulna, when the elbow-joint is in extension.
The trochlear concavity, in passing from before
backwards, takes a curved direction, so that its
posterior extremity is much nearer the external
part of the articular cylinder than the anterior.
This has an important influence on the direc-
tion of the motions of the forearm. These
two depressions are separated from each other
by a thin osseous lamina, almost transparent.
We sometimes meet with instances in which
this lamina is perforated in consequence of a
defect of ossification ; and Meckel states that
he has found this perforation more frequently
in the bones of Negroes and Papuas than in
those of the superior races of mankind. It is
the permanent condition of manypachydermata,
rodentia, carnivora, and quadrumana. On the
inside the trochlear concavity is bounded
by a thick and projecting lip, which, when the
bone is placed at right angles with a horizontal
plane surface, descends lower down than any
other part, so that this part comes in contact
with the plane surface, while the remaining

EXTREMITY.

161

portion of the articular cylinder is raised con-
siderably above it. This arrangement accounts
for the hollow angle manifest on the outer side of
the elbow-joint when the forearm is extended.

We have yet to describe two processes
which are connected in great measure with the
outer and inner extremities of the articular cy-
linder, and to which we have already referred,
as being the points in which the margins of
the bone terminate. The external one is trian-
gular and thick, rough upon its surface, and
projects slightly. It is improperly called the
external condyle — more correctly it should be
designated epicondyle, being applied to the
outer surface of what is properly the external
condyle. This process affords attachment to
the external lateral ligament of the elbow-
joint and to the principal supiriator and ex-
tensor muscles on the forearm, whence it has
been called condylus extenxorius. The inter-
nal process is very prominent, distinctly trian-
gular, terminating the inner edge of the hu-
merus and connected with the trochlea; it is
more correctly denominated epitrochlea. It
affords insertion to the internal lateral ligament,
and to the pronator and flexor muscles of the
forearm. Its posterior surface is slightly hol-
lowed at the line of its junction with the rest
of the bone ; the ulnar nerve passes behind it.

The humerus is the principal lever of the
pectoral extremity ; hence in all animals its
strength is proportionate to the force and power
which is required in the limb. In the ele-
phant it is a massive pillar of support; and
here we may notice a variety following the
same law which influences the difference in
the aspect of the glenoid cavity of the scapula,
already noticed ; namely, that the angle be-
tween the axes of the head and shaft of the
humerus, is at its maximum when the arm-
bone is mainly an instrument of support, and
diminishes as that bone is more used for pre-
hension and other purposes ; and as this use is
found for this bone chiefly in the human sub-
ject, we may presume that in man the angle
in question is the least removed from a right
angle. When this limb is used mainly for
support and progression, a considerable range
of motion in the shoulder-joint is not required,
the tuberosities at the upper extremity of the
bone project and limit the motions of the joint.
When, however, a considerable motion is ne-
cessary, these tubercles are depressed as in man,
so as not to interfere with these motions. The
lower extremity of the humerus likewise affords
marks indicative of the mobility of the fore-
arm and hand ; thus, in the one case one or
both of the edges of the bone which terminate
in the epitrochlea and epicondyle are promi-
nent and strong in proportion as the muscles
which arise from it are frequently called into
play, as when the pronating and supinating
motions of the forearm are extensive : in the
other case this ridge is imperfectly developed,
and the principal modification of the lower end
of the bone is to be seen in the articular cy-
linder, where greater depth is given to the
trochlea, in order to afford increased strength
and security to the elbow-joint.

VOL. n.

One of the most singular instances of the
developement of bony processes in accordance
with muscular power is in the case of the mole.
In this little animal the whole anterior ex-
tremity is constructed entirely with reference
to its burrowing habits; its short, thick, and
almost square clavicle and its elongated lever-
like scapula tend to the same end, as its amaz-
ingly strong humerus. The upper extremity
of this latter bone is extremely broad ; it pre-
sents two articular surfaces, being articulated
with the clavicle as well as with the scapula,
and the tuberosities which give insertion to
the muscles of rotation are enormously de-
veloped. The body of the bone is short, thick,
and strong ; the inferior extremity is nearly as
large as the superior ; both the epicondyle and
epitrochlea are very highly developed, especially
the latter, which is accounted for by the fact that
the muscles of pronation are those most called
into action, in order to enable the animal to
employ the accessory bone on the radial side of
the hand, in scraping up the earth. This
large size of the humerus, and great develope-
ment of its muscular eminences, is found in all
fossorial animals, as the megatherium, the pan-
golins, beavers, ant-eaters, moles, and mono-
tremata. In the two last the developement is
the most remarkable.

In the class of Birds, the humerus is de-
veloped as regards the prominence of its mus-
cular protuberances, in proportion to the
powers of flight. In birds which fly, those
eminences are strong and prominent, and the
bone itself is proportionally strong; but in those
which do not fly, the bone is weak and gene-
rally short. In the common pigeon, for ex-
ample, the enlargement of the scapular ex-
tremity of the humerus, and the developement
of the tubercles is very manifest, as well as
the strength and thickness of the shaft of the
bone.

Structure. — The structure of the humerus is
characteristic of that of long bones in general.
In a vertical section we observe that the re-
ticular texture is chiefly accumulated towards
the extremities; the shaft being mainly formed
of compact tissue. At the upper extremity we
notice the mark of union of the epiphysis of
the head, which corresponds to the line of the
anatomical neck of the bone. The canal, when
a transverse section of it is viewed, appears
somewhat quadrilateral in form. Its walls are
formed of very dense compact tissue.

Developement. — The ossification of the hu-
meius begins in its shaft, and that very early,
according to Meckel about the second month ;
the shaft goes on enlarging, but the extremities
are still cartilaginous during the whole of in-
tra-uterine life, and for the first year after birth.
The superior extremity is developed by two
points of ossification, one for the head, the
other for the great tuberosity ; about the be-
ginning of the second year the ossification of
the head of the bone commences, and from,
the four-and-twentieth to the thirtieth month
the ossification of the great tuberosity begins.
According to Beclard, a small ossific point for
the lesser tuberosity is visible in the fifth or

162

EXTREMITY.

sixth year ; from the eighth to the ninth year
the ossifie elements of the head of the hume-
rus become united and the head is com-
pleted.

The inferior extremity of the humerus, accord-
ing to Cruveilhier, begins to ossify later than the
superior. The first point of ossification noticed
in it is for the external condyle : this appears at
the age of two years and a half; at seven years
a second point of ossification commences for the
epitrochlea ; at twelve a third point appears for
the internal edge of the trochlea; and at sixteen
years a fourth point for the epicondyle. These
four points of ossification, Cruveilhier states, are
united in the following order: first, in the
second year, the two points of the trochlea are
united; and, secondly, at sixteen years the
trochlea, epicondyle, and the condyle form a
a single piece.* The union of the extremities
with the shaft of the bone takes place from the
eighteenth to the twentieth year; and all ob-
servers agree in stating that the union of the
inferior extremity -with the shaft always pre-
cedes that of the superior extremity, although
the ossification of the latter is prior.

Forearm. — The bones of the forearm are
the ulna and radius, of which the former con-
stitutes the second essential element in the
elbow-joint, the radius being chiefly an acces-
sory bone to provide for the wider range of
motion of the hand. The ulna therefore is the
principal lever of the forearm, and the motions
of flexion and extension of that segment of
the limb upon the arm depend upon it ; at its
superior extremity it forms a very firm hinge-
joint with the trochlea of the humerus, but in-
feriorly its connexion with the carpus at the
wrist-joint is very slight, and it forms by no
means an essential element of that joint On
the other hand, the radius at its inferior ex-
tremity forms a very important part of the
wrist-joint, but at its superior its connection
with the elbow-joint is due to its necessary
articulation with the outer side of the ulna.

Ulna (x.v@trov, cubitus; Fr. os du coude ;
Germ, das EUenbogenbein.-\) This bone is
situated on the inner side of the forearm. It is
the longest and the largest bone of that region,
and in the vertical position of the limb it is
directed downwards and a little outwards, the
obliquity being occasioned by the greater pro-
jection downwards of the inner lip of the
trochlea of the humerus, as already alluded to
in describing that bone.

The upper or humeral extremity of the ulna
is at once distinguished by its great size from
the inferior extremity. It consists of two pro-
cesses joined to each other at a right angle, and
so that that angle opens forwards. One of
these processes is vertical, and is continued in

* Cruveilhier, Anat. Descr. torn. i. p. 231.

t The tennfocile was aj plied to this bone as well
as to the radius by some of the ancient anatomists,
in imitation of the Arabians, who used the word
xend, sc. an instrument analogous to our tinder-box,
which consisted of two sticks, similar in appear-
ance and proportions to the bones of the forearm.
Focile majus was the ulna, focik minus the radius,
lilurmnbach, Beschreibung der Kuochen, p. 395.

the direction of the long axis of the bone, and
is little else than a continuation of the shaft ;
this is the olecranon : the other is horizontal,
anterior to the olecranon, as it were placed
upon the superior extremity of the bone, so
as to project considerably beyond the plane
of its anterior surface : this is the coronoid
process.

The olecranon, (uhtvn, cubitus, xgavov, caput,}
also called processus anconaus, may be said to
begin from the angle of junction of the coro-
noid process with it; there the bone appears
slightly constricted, for above that point it ex-
pands. We notice five surfaces upon it. The
superior surface is horizontal ; it presents pos-
teriorly a muscular impression affording inser-
tion to the triceps extensor, and anteriorly it
ends in a remarkable beak, which, in the state
of complete extension, is received into the ole-
cranon cavity of the humerus. The posterior
surface is rough with a very obviously trian-
gular outline ; this surface gives insertion
to the triceps muscle. The internal surface
is also rough, and covered by the fibrous ex-
pansion from the tendon of the triceps, and
at its anterior margin affords insertion to the
superior fibres of the internal lateral ligament.
The external surface is smooth, and also is
covered by the fibrous expansion from the ten-
don of the triceps. The anterior surface is
articular ; it presents the appearance of having
been covered by articular cartilage ; it is divided
by a rounded vertical ridge into two unequal
portions, of which the internal is larger than
the external. This surface is limited below by
a transverse depression, non-articular, in which
some fatty matter is deposited in the recent
state. The surface is convex from side to side
in the centre, and each of its lateral portions is
concave; the whole surface is concave from
above downwards. In the extended state of
the forearm this articular surface of the olecra-
non is applied to the posterior part of the
trochlea of the humerus ; it forms the posterior
part of the great sigmoid cavity of the ulna.

The coronoid process is wedge-shaped, at-
tached by its base to the anterior surface of the
ulna, the sharper edge projecting forwards and
free. This edge is convex, and sometimes
forms a point ; it is received into the coronoid
cavity of the humerus. On the external sur-
face of the coronoid process is an oval articular
facet, concave from behind forwards, whose
long axis is horizontal ; this is the lesser sigmoid
cavity, and is articulated with the inner side of
the head of the radius ; the internal surface is
rough, and has a projecting lip, which affords
attachment to the anterior fibres of the internal
lateral ligament. The anterior surface is in-
clined from above downwards and from before
backwards, so that its aspect is downwards and
forwards ; it is slightly hollowed transversely,
and is rough, the roughness being continued
down for a little way in front of the bone, thus
forming a rough surface triangular in form, the
base corresponding to the anterior edge of the
coronoid process ; this surface affords insertion
to the brachiaeus anticus muscle. The superior
surface forms the anterior portion of the great

EXTREMITY.

163

sjgmoid cavity ; like the similar surface on the
olecranon, it is divided by an obtuse ridge
directed from before backwards, into two une-
-qual portions ; these portions correspond in
shape and size with those already noticed on
,the olecranon.

The shaft of the ulna gradually tapers from
.above downwards ; it is triangular in its entire
extent, excepting for about an inch above the
inferior extremity, where the bone is distinctly
cylindrical. On the shaft anatomists commonly
describe three surfaces. The anterior surface
is broader in the middle than at its extremities;
it is slightly concave in the transverse direction
in its middle third ; on this surface, at its upper
part, we notice the orifice of the nutritious canal,
which is directed upwards towards the coro-
noid and olecranon. By its three superior
fourths this surface affords attachments to the
flexor digitorum profundus, and by its inferior
fourth to the pronator quadratus ; the place of
attachment of this latter muscle is limited above
by an oblique line which passes from without
inwards and from above downwards. The in-
ternal surface is smooth, and convex in its en-
tire extent; widest above, it gradually tapers to
the inferior extremity. In its inferior fourth it
is subcutaneous, and to its three superior
fourths is attached the deep flexor muscle of
the fingers ; the aspect of this surface is back-
wards as well as inwards.

The third surface is posterior. The two in-
ferior thirds of this surface are smooth, the mid-
dle being flat and the lowest rounded ; here
are attached the extensor muscles of the thumb
and that of the index finger. In the superior
third we distinctly notice two surfaces, easily
distinguishable by the difference of aspect; the
internal one, which is continued up on the
olecranon process, looks backwards and slightly
outwards; to it the anconaeus muscle is attached
superiorly, and inferiorly the extensor carpi
ulnaris. The external of these two surfaces
looks directly outwards, and is separated from
that last described by a line which passes ob-
liquely downwards and inwards ; to this sur-
face, which commences just below the lesser
sigmoid cavity, the supinator brevis is attached,
and below it, commences the line of attachment
of the extensor muscles already alluded to.

Three edges separate the surfaces above de-
scribed ; of these the external is at once distin-
guished by its greater prominence ; it is sharp
in nearly its two inferior thirds, and superiorly
is lost on the surface to which the supinator
brevis is attached ; all that part of this edge
which is prominent and sharp gives insertion
to the interosseous ligament. The anterior
edge commences just below the coronoid pro-
cess, and terminates, inclining a little back-
wards, in front of the styloid process of the
ulna : it is rounded and smooth in its entire
extent, and has the deep flexor of the fingers
and the pronator quadratus inserted into it.
The posterior edge commences at the apex of
the posterior surface of the olecranon, and ter-
minates insensibly towards the inferior fourth
of the bone.

The inferior or carpal extremity of the ulna

is very small; it forms a slightly rounded
head ; on its posterior and internal part is a
small process, projecting vertically downwards
and ending in a point, to which the internal
lateral ligament of the wrist-joint is attached :
this process is the styioid process ; external to this
is a depression or pit, into which is inserted
the triangular cartilage of the wrist-joint, and
external to this depression is the rounded head,
which is smooth on its inferior surface, covered
with cartilage in the recent state ; the triangular
cartilage glides upon this surface. On the
outer side of the head is an articular convexity
which articulates with a concave surface on the
inner side of the carpal extremity of the radius.
On the posterior surface of the head, imme-
diately external to the styloid process, there is
a slight channel, in which is lodged the tendon
of the extensor carpi ulriaris.

Structure. — The olecranon and coronoid
processes are completely cellular in structure,
excepting the external cortex of compact tissue.
The inferior extremity of the ulna is likewise
cellular, but the shaft is mainly composed of
compact tissue, hollowed by a medullary canal,
which commences a little below the coronoid
process, and terminates just above the inferior
extremity.

Radius, (Germ, die Speiche,) so called from
its being compared to the spoke of a wheel ; it
is the shorter of the two bones of the forearm ;
its proportion to the ulna being as 11 to 12.

The superior extremity or head of the radius
is a cylindrical head excavated on its superior
surface so as to form a superficial cavity, cavitas
glenoidea, which is articulated with the external
condyle of the humerus. The circumference of
this head consists of a deep lip of bone present-
ing a smooth surface covered by cartilage in the
recent state, the depth of which, measured verti-
cally, is greatest on the inner side, so as there to
form an oval convex articular facet which is
adapted to the lesser sigmoid cavity of the ulna ;
the remainder of the circumference is embraced
by the annular ligament of the radius. The head
of the radius is connected to the shaft by a short
and cylindrical neck, which passes obliquely
downwards and inwards; the neck of the radius
is limited inferiorly and on the ulnar side by a
rounded tubercular process, into the internal
posterior and rough partof which the biceps mus-
cle is inserted, the bicipital tuberosity or tubercle
of the radius; the anterior part of this tubercle,
over which the tendon of the biceps glides, is
smooth. For about an inch below this process
the bone retains the cylindrical form, being
here embraced by the inferior fibres of the su-
pinator brevis muscle ; but below this the bone
becomes distinctly prismatic in its form, and
begins to expand to its inferior or carpal extre-
mity. We here describe three surfaces as in
the ulna : the anterior is inclined inwards, its
aspect is forwards and inwards ; about its
middle this surface is slightly hollowed from
above downwards; at the junction of its middle
and inferior third it is convex, and in its inferior
third, where it attains its greatest lateral expan-
sion, it is concave again. At the superior third
of the bone we notice on this surface the nutri-

164

EXTREMITY.

tious foramen, the canal following the same
direction as that of the ulna, namely upwards.
The muscles attached to the anterior surface of
the radius are the flexor pollicis proprius, con-
nected with the two superior thirds of the bone,
and the pronator quadratus occupying the 'in-
ferior third. The posterior surface of the radius
is likewise inclined, and looks backwards and
inwards, very narrow in its whole extent, but
broadest at its inferior extremity, convex in its
superior and inferior thirds, and slightly con-
cave from above downwards in its middle third.
This last portion of the bone affords attachment
to the two inferior extensor muscles of the
thumb ; the superior third is embraced by the
supinator brevis, and the inferior third has
applied to it the tendon of the common extensor
of the fingers, the indicator, and the extensor
tertii internodii pollicis. The external surface
is convex in its whole extent, and like the
others expands inferiorly; about its middle we
observe a rough surface, which gives insertion
to the pronator quadratus ; in its upper portion
the surface is embraced by the supinator brevis,
and inferiorly the radial extensors of the wrist
are applied to it.

Of the three edges which separate these sur-
faces, the internal is sharp, and extends from
about an inch below the bicipital tuberosity to
about the same distance above the carpal extre-
mity of the radius; at this latter point the edge
seems to bifurcate and form a plane triangular
surface above the inferior extremity of the ra-
dius. This edge gives attachment in its entire
extent to the interosseous ligament. The an-
terior edge is rounded ; it distinctly originates
from the bicipital tuberosity, and terminates at
the outer side of the carpal extremity of the
radius in front of the styloid process. 'The su-
pinator brevis, the proper flexor of the thumb,
and the flexor sublimis of the fingers, have
attachments to this edge above, and below
the pronator quadratus and supinator longus
are inserted into it. The posterior edge is very
imperfectly defined, being distinct only in its
middle.

The inferior or carpal extremity of the radius
is the largest part of the bone ; it is irregularly
quadrilateral in form. Its inferior surface
forms an articular excavation, the outline of
which is triangular, the apex being external
and the base internal ; this surface is divided
into two by a slightly prominent line which
passes from before backwards ; the outer of
these two portions retains the triangular form,
and is articulated with the scaphoid bone of
the carpus; the internal is quadrilateral, and
articulated with the lunar bone. At its inner
margin, this surface is continuous with a slightly
excavated articular facet on the ulnar side of
the inferior extremity of the bone, which is
articulated with the convex surface on the cor-
responding part of the ulna. The inferior ex-
tremity of the radius presents, at its outer part,
a pyramidal process projecting downwards and
slightly outwards ; this is the styloid process,
which by its apex gives attachment to the ex-
ternal lateral ligament of the wrist-joint. The
anterior margin of the inferior extremity is

slightly concave from side to side ; it gives at-
tachment to the anterior ligament of the wrist-
joint, and the tendons of the flexor muscles of
the fingers pass over it into the palm of the hand.
On the posterior margin of this extremity we
observe two grooves : the internal one, wide and
very superficial, lodges the tendons of the com-
mon extensor of the fingers and the indicator ;
the exteraal, deeper and oblique, lodges the
extensor tertii internodii pollicis. Externally
we notice likewise two superficial grooves, of
which the posterior lodges the radial extensors
of the wrist, and the anterior is traversed by the
extensores primi et secundi internodii pollicis.

Structure. — The central canal extends up-
wards into the neck of the bone; it is cylin-
drical at the extremities, and prismatic in the
centre. Both extremities are composed of can-
cellated structure.

Developement of' the bones of the fore-arm. —
Both bones appear about the same time, and if
not synchronously with the humerus, at least a
very little later. With both bones the ossifi-
cation begins on the shafts, which are very
early completed ; the ossific point of the shaft
of the radius is said, by Beclard and Cruveil-
hier, to begin some days before that of the
ulna. In the radius the inferior extremity
begins to ossify before the superior, about the
end of the second year. The ossification of
the superior extremity begins between the
seventh and ninth year; it is united to the
shaft about the twelfth year, whilst the inferior
extremity, whose ossification begins earlier, is
not united till the eighteenth or twentieth year.
The progress of the ossification of the ulna is
very similar. The inferior extremity developed
by a single point of ossification begins first,
about the sixth year. A little later the olecra-
non begins to ossify; the coronoid is formed
by an extension of ossification from the
shaft. The union of the superior extremity of
the ulna with the shaft takes place about the
fifteenth or sixteenth year ; that of the inferior
about the eighteenth or twentieth.

It is important to observe that the articula-
tion of the radius with the ulna, in the manner
in which it is effected in man, has reference to
the motions of the hand. Pronation and supi-
nation of the hand are effected by the rotation
of the head of the radius within the coronary
ligament and on the lesser sigmoid cavity of
the ulna. The hand is so connected with the
radius that it follows the motions of that bone;
when, therefore, the radius rotates in such a
direction that its inferior part crosses the ulna,
the posterior edge is directed outwards, and its
anterior surface inwards and backwards; the
palm of the hand is turned backwards and the
dorsum forwards; the forearm and hand are
then said to be in pronation. On the contrary,
when the rotation is such that the ulna and ra-
dius are placed on the same plane, the dorsum
of the hand is directed backwards and the palm
forwards ; this is supination.

In the lower animals we never find this mode
of articulation of the radius with the ulna,
unless there be also present the motions of su-
pination and pronation of the hand. In such

EXTREMITY.

165

animals, evidence of the existence of these
motions is afforded by certain points in the
conformation of the radius and ulna them-
selves, such as the peculiar form of the head
of the radius, and the concave articular sur-
face on the ulnar side of its lower extremity,
as well as the lesser sigmoid cavity of the
ulna, and the convexity on the radial side of the
head of the same bone. This is found in many
of the Carnivora, but chiefly in the Quadru-
mana.

In the Ruminants and Solipeds the radius
and ulna are consolidated together so as to
form one bone ; they can, however, be distin-
guished at the humeral end, where the latter
bone is conspicuous by its elongated olecranon,
which not only affords insertion to the extensor
muscles of the arm, but also increases the secu-
rity of the elbow-joint. The radius, which is
the principal bone of the fore-arm, is so arti-
culated with the humerus as to admit of free
flexion and extension, but it is fixed in the
state of pronation. In many of the other Mam-
malia the radius and ulna are distinct through-
out, but do not admit of the rotation of the
one on the other ; this is the case in Rodentia,
many Carnivora, Pachydermata, Edentata, In-
sectivora, and Cetacea. In the Sloth, how-
ever, among the Edentata, the motions of pro-
nation and supination are conspicuous, and the
olecranon is imperfectly developed; on the
contrary, in the Edentata proper, as the Arma-
dillo, Megatherium, &c. these motions do not
exist, and the olecranon is very much deve-
loped. In the Cheiroptera the radius is the
principal bone of the fore-arm, the ulna being
developed only as to its humeral extremity
consisting sometimes of little more than its
olecranon ; and in some, as the Vespertilio vam-
pyrus, the olecranon exists in the form of a pa-
tella, connected with the upper extremity of
the ulna.

In Birds the radius and ulna are distinct
throughout, but do not admit of motion between
them; they are fixed in a state intermediate be-
tween pronation and supination.

The Hand. — The third division of the upper
extremity is the hand : for the description of
the bones which compose it, we refer to the
article HASD.

Inferior extremity. — The bones which form
the skeleton of the inferior or pelvic extremity
are the femur, tibia, fibula, and the bones of
the foot, occupying subdivisions of this mem-
ber, which correspond to the arm, forearm, and
hand in the pectoral extremity.

Femur (thigh-bone, os femoris v. cruris, os
coxa. Fr. os de la cuisse, le femur. Germ, das
Schenkelbein.) This is the largest and longest
bone of the skeleton ; it constitutes the upper part
of the inferior extremity, and is articulated with
the pelvis above and the tibia inferiorly. The
femur exhibits very obviously the characteristic
marks of the class of long bones in its elonga-
ted and cylindrical shaft, and its swollen extre-
mities.

The superior extremity of the femur consists
of a spherical head, connected to the shaft of
the bone by a neck. The head is very regu-

larly spheroidal, being nearly two-thirds of a
sphere ; it is limited towards the neck by a
waving line which passes all round, and corr£-
sponds to the margin of the acetabulum. The
whole head of the femur is incrusted in the
recent state with articular cartilage, excepting
at one point, where there is a depression or pit,
varying in depth in different subjects. The
precise situation of this depression is just infe-
rior and posterior to the point at which the axis
of the head of the femur would pass out : into
this depression the ligamentum teres is in-
serted.

From the head of the femur is prolonged
outwards and downwards to the upper end of
the shaft the neck (cervix v. collumfemoris).
This portion of bone, cylindrical where it is
connected to the head, gradually expands as it
proceeds outwards, and is flattened in front
and behind. That portion of the neck of
the femur which is connected with the shaft
may be called its base; here we observe two
lines, by which the demarcation between the
neck and shaft is indicated ; one of these lines
is anterior, being simply a rough line extending
from the great trochanter obliquely downwards,
inwards, and slightly backwards to the lesser
trochanter, and thence called the anterior inter-
trochanteric line, into which the capsular liga-
ment of the hip-joint is inserted ; the other line
may be more correctly designated a prominent
ridge ; it is situated at the posterior part of the
base of the neck, and extended also between the
trochanters, the posterior inter-trochanteric line.
The anterior surface of the neck of the femur is
for the most part plane, but slightly concave
just external to the line of junction of the head.
The superior surface of the neck is concave,
being limited on the outside by the great tro-
chanter ; the posterior surface is likewise con-
cave, being, as it were, hollowed from within
outwards. The inferior surface is slightly con-
cave from above downwards, but rounded from
before backwards : this surface inclines down-
wards and outwards, and at its termination is
connected with the trochanter minor behind,
and the inner side of the shaft of the bone in
front ; in length it exceeds all the rest ; the su-
perior surface is the shortest, and the posterior
is longer than the anterior. On all the surfaces
of the neck we observe numerous foramina for
the transmission of vessels into the substance
of the bone; these foramina are largest and
most numerous on the superior surface.

At the superior angle of the base of the neck
of the femur, and at the upper and outer part
of the shaft of the bone, we observe a large and
thick process, the trochanter major, (from
T^Q^ctu, roto,) processus exterior femor is ; it is
a prolongation upwards of the shaft of the
bone, but its most elevated point is below the
level of the head of the bone, corresponding to
the upper part of the line of junction of the
head with the neck. " This eminence," says
Cruveilhier, " whose size is considerable, and
which makes a very manifest prominence under
the skin, ought to be studied with care in its
relations as to its relative position ; first, with
the crista ilii, beyond which it projects exter-

166

EXTREMITY.

nally; secondly, with the external condyle of
the femur; thirdly, with the malleolus exter-
nus, because these relations are constantly va-
luable guides, as well in the diagnosis as in
the reduction, of the luxations of the femur and
of the fractures of the neck or shaft of the
bone."

The external surface of the great trochanter
is convex and rough, and the tendon of the
glutceus maximus muscle covers it in the recent
condition ; this surface is terminated below by
a projecting line, into which is inserted the
upper extremity of the vastus externus muscle.
The internal surface is of much less extent : it
is placed at right angles with the superior sur-
face of the neck of the bone, and at its posterior
part it is excavated so as to form a deep pit or
depression, the digital cavity orjbssa trochante-
rica, into which are inserted the tendon of the
pyriformis, the gemelli, and the obturatores
internus and externus. The anterior edge is
thick and irregular; the glutcei medius and
minimus are inserted into it, the former into
its inferior, the latter into its superior part.
Superiorly the trochanter forms a thin edge,
more or less pointed, into the interior half of
which the glutceus minimus is inserted, and
into its posterior or pointed portion the glutceus
medius; it may in general be observed, that
the size of this pointed part of the superior
edge of the great trochanter is proportionate to
the developement of the glutoeus medius mus-
cle. The posterior edge is convex and thick,
and gives attachment to the quadratus femoris
muscle.

At the inferior angle of the base of the cervix
femoris, and on the internal and posterior part,
we notice a short conical process, trochanter
minor, (processus interior femor is,) attached
to the bone by its base, its apex directed
downwards, inwards, and backwards, smooth
on its whole surface. This process affords
insertion to the tendon of the psoas and iliacus
muscles.

In the male adult, theaxisof the head and neck
of the femur passes downwards, outwards, and
slightly backwards, and forms an obtuse angle
with the shaft, an angle of about 135 degrees.
In the female this angle is somewhat smaller, and
approaches more nearly to a right angle, which
contributes with the greater lateral dimensions
of the pelvis, to increase the distance of the
trochanters of opposite sides from each other,
and to cause that projection of these processes
which forms a peculiarity of the female form.
In early age, when the neck of the femur is
imperfectly developed, the angle between the
neck and shaft is not denned ; in the earliest
condition the connexion of the head and shaft
very much resembles the permanent condition
of the corresponding parts in the humerus ; as
the neck becomes developed, the angle is ren-
dered apparent, at first, however, little removed
from a right angle, but subsequently it in-
creases up to the adult period ; after that time
we often find that the neck of the bone dimi-
nishes in its dimensions, and the angle is con-
sequently altered, so as to approximate to a
right angle.

The following may be given as the mean
measurements of the different parts of the neck
of the femur. In the centre it measures about
one inch, its posterior surface about fifteen
lines, its inferior edge about twenty lines, and
its superior about eleven lines ; its vertical
diameter, in its most contracted part, is about
seventeen lines, and its antero-posterior about
ten.

The shaft of the femur forms a slight curve
from above downwards, convex anteriorly and
concave posteriorly, the excavation thus formed
behind being filled up by the powerful muscles"
on the back of the thigh. It likewise presents
the appearance as if it had been twisted, like
that which we have noticed in the humerus,
the inferior extremity being twisted inwards,
the superior in the contrary direction. Cru-
veilhier remarks, that this curvature of torsion
is in relation with the disposition of the femoral
artery, which in its spiral course passes from
the anterior to the posterior surface of the bone.

In the greater part of its extent the shaft of
the femur is prismatic ; at the superior extre-
mity it is expanded laterally and flattened ; at
the inferior it is likewise very considerably ex-
panded.

The anterior surface of the shaft is smooth
and rounded ; at the upper part it is a little
rough: this surface is covered completely by
the triceps extensor muscle. The posterior
surface is divided along the middle into two,
which are inclined, the one forwards and in-
wards, the other forwards and outwards ; the
external surface is covered by the vastus exter-
nus, the internal by the vastus internus. In
the middle, separating these two surfaces, is a
rough ridge, linea aspera, which occupies two-
fifths of the shaft of the bone about its middle,
but is bifurcated above and below. Superiorly
the bifurcation takes place about the termina-
tion of the superior fifth ; two lines proceed,
the external, rough and prominent, to the great
trochanter ; the internal, rather indistinct, to the
lesser trochanter. The external line gives in-
sertion to the vastus externus, the adductor
magnus, and the glutceus maximus ; the pecti-
naeus and the vastus internus are inserted into
the internal line. Inferiorly, the bifurcation
takes place at a point corresponding to the
commencement of the two inferior fifths ; each
line proceeds down to the corresponding con-
dyle, and a triangular space is thus enclosed,
the base of which is formed by the posterior
extremities of the condyles, and the apex is at
the point of bifurcation of the linea aspera.
This space, which presents a smooth surface,
slightly concave in both the vertical and trans-
verse directions, forms the floor of the popliteal
region. The external line, from the inferior
bifurcation, is more prominent than the inter-
nal, and gives insertion to the vastus externus
and to the short head of the biceps. The in-
ternal is very faint superiorly where the femoral
artery passes over it, and inferiorly the vastus
internus and the adductor magnus are inserted
into it.

The nutritious foramen of the femur is found
either upon, or on one side of, the liuea aspera.

EXTREMITY.

167

The direction of the canal is upwards towards
the head of the femur.

The inferior extremity of the femur is much
more considerable than the superior. We no-
tice upon it two articular processes of large
size, united in front, but separated by a deep
depression posteriorly. These processes are the
external and internal condyles ; at the point of
union of these two condyles in front, *we ob-
serve a transversely concave surface, which ex-
tends for a little distance upwards upon the
anterior surface of the bone ; this is the trochlea
of the femur, on which the patella moves. The
deep notch which separates the condyles poste-
riorly is denominated the intercondyloid notch.

Each condyle is ovoidal in its outline and
convex. The external condyle is placed di-
rectly under the external part of the femur; it
projects more forwards than the internal con-
dyle ; its antero-posterior diameter is less than
that of the internal condyle, but its trans-
verse is greater. On the other hand, the in-
ternal condyle projects inwards out of the
plane of the internal surface of the bone;
its posterior extremity extends much further
backwards than that of the external, and if
the bone be placed at right angles with a
plane surface, it will be seen that this condyle
alone touches that surface, a circumstance
which arises from the internal condyle project-
ing downwards more than the external. It is
also worthy of notice, as resulting from this
conformation of the internal condyle, that in
order to bring both condyles in contact with a
plane surface, the bone must be made to in-
cline with the inferior extremity inwards. Above
the posterior extremity of each condyle there is
a depression for the insertion of the two heads
of the gastrocnemius muscle.

The external surface of the external condyle
is continuous with the outer surface of the
shaft; it is rough and convex, and is called by
some anatomists the external tuberosity. At its
posterior part there is a prominent tubercle to
which the external lateral ligament is attached,
and below and a little posterior to this is a de-
pression into which the tendon of the popliteus
is inserted. The internal surface of this con-
dyle forms the outer wall of the depression
which separates the condyles behind; it is
concave, and has the anterior crucial ligament
inserted into it. The inner wall of this notch
is formed by the external surface of the in-
ternal condyle, which is likewise concave, and
into it are implanted the fibres of the pos-
terior crucial ligament. The internal surface
of this condyle, or the internal tuberosity, is
rough, much more convex than the external
tuberosity; the internal lateral ligament and
tendon of the adductor raagnus are inserted
into it. Both the tuberosities are perforated
by a number of minute foramina for the trans-
mission of vessels to the cancellated texture.

Structure. — A vertical section of the femur
demonstrates its structure to be the same as
that of all the long bones, composed of can-
cellated texture at the extremities and com-
pact in the shaft, which is bored by a cylin-
drical canal. Posteriorly the compact tissue is

of great density and hardness, especially wriere
it forms the linea aspera or spine of the bone.
When the section of the femur is made so as
to divide the neck vertically in its long axis
into two equal portions, we observe how ad-
mirably the arrangement of the osseous texture
in this part is adapted to the function which it
has to perform. The head is entirely composed
of reticular texture surrounded by a thin cortex ;
this cortex gradually increases in thickness on
the upper surface of the neck till it reaches the
great trochanter. On the inferior surface of the
neck, however, the compact tissue, although
thin near the head, becomes very much in-
creased in thickness as it curves downwards
and outwards to the lesser trochanter. We
observe, moreover, that although the principal
portion of the head and neck are composed of
reticular texture, in certain parts this texture is
more loose than in others. From the upper part
of the head to the thick part of the compact tissue
on the inferior surface of the neck, a series of
parallel fibres proceed in an oblique course,
and closely applied to one another; these fibres
receive and transmit the weight to the arch of
the neck. Again, the reticular texture is loose
and rare, external to these fibres and in all the
inferior part of the head of the bone where no
stress is laid upon the bone.

Developement. — According to Beclard, the
femur begins to ossify before the humerus ; its
ossification commences about the thirtieth day
by a point for the shaft. A second point of
ossification is for the inferior extremity, and
this consists in a single osseous nucleus which
is formed within the last month of fo?tal ex-
istence, and is situated between the two con-
dyles, occupying the centre of the cartilage.
According to Cruveilhier this osseous nucleus
appears during the last fifteen days of intra-
uterine life. " The constant presence," adds
this author, " of this osseous point in the inferior
extremity of the femur is a fact of great im-
portance in legal medicine ; because from the
knowledge of this circumstance alone, namely,
that this nucleus exists in the epiphysis of the
inferior extremity of the femur of a fetus, we
can pronounce that foetus to have arrived at its
full period."

The neck of the femur is formed by an ex-
tension from the body. The head has a distinct
point of ossification which begins to form at
the end of the first year. The trochanters have
each a separate point of ossification ; that of
the great trochanter is formed about the third
or fourth year, that of the lesser from the thir-
teenth to the fourteenth year. These several
osseous points are united to the shaft about the
period of puberty in the following order; first,
the trochanter minor, next the head and trochan-
ter major, and lastly the inferior extremity.

In the skeleton the femur is articulated so
that its inferior extremity approximates the
corresponding part of the bone of the op-
posite side, while the superior extremities are
separated from each other to a considerable
extent. One object of this oblique position*'
the femora has been already referred to, namely,
to bring both condyles of each femur in con-

168

EXTREMITY.

tact with the articular surfaces of the vertical
tibise. In women, in consequence of the more
horizontal position of the neck of the femur
and the greater width of the pelvis, the ob-
liquity is more manifest, and hence they are
naturally more in-kneed than men, as from
the greater projection of the internal condyle
that surface alone would come in contact
with the tibia if the position of the femur
were vertical. The separation above is ef-
fected by the neck of the bone, and the ad-
vantage of this arrangement is to give a more
favourable insertion to the muscles of rotation ;
they thus acquire a lever power proportionate
to the length of the neck, a fact which is
abundantly manifest by comparing the relative
powers of rotation in the shoulder and hip
joints; in the former these motions are more
extensive, because, from the peculiar form of
the joint, the obstacles to extent of motion are
fewer; in the latter they are effected with greater
power at a less expense of muscular force.

In comparing the femur of man with that of
the lower mammalia, we notice the imperfect
developement or the non-developement of the
cervix in the latter, the head in some being
placed nearly vertically over the shaft of the bone,
and also the small size of the trochanters, and
the magnitude of the trochanter major in some
classes. The curved form of the shaft of the
femur is much less in the lower mammalia
than in man ; in some the femur is perfectly
straight, and as a consequence the linea aspera
or spine is indistinctly marked. The propor-
tionate length of the femur to the other bones
of the inferior extremity differs also : in man
it exceeds that of the tibia; in the inferior
mammalia, although in most cases the strongest
bone, the femur is shorter than the tibia, and
shorter even than the foot, although longer
than each segment of this portion of the limb.
The trochlea in the inferior extremity is deeper,
and the transverse dimensions of the condyles
are less than in man.

Patella, (rotula, knee-pan, os sesamoideum
maximum, Bertin ; Fr. la rotule.; Germ, die
Kniescheibe). This bone, although belonging
to the class of sesamoid bones, is yet so fully
developed in the adult human subject, and is
so essential to the integrity of the knee-joint, that
it is usual to examine its anatomical characters
along with those of the other bones of the in-
ferior extremity. Its developement in the tendon
of the rectus femoris leads to its being classed
amonejthe sesamoid bones.

The patella is of a triangular form, the apex
being directed downwards and the base up-
wards ; the former is connected with the tibia
by the continued tendon of the rectus, under
the name of ligamentum patellae; the tendon
of the rectus and die tendinous expansions of
the triceps extensor are inserted into the base,
which expansions are likewise implanted into
the margins of the bone, so that the whole
circumference and anterior surface of the pa-
tella are invested with tendinous fibres.

The anterior surface of the patella is very
slightly convex, and exhibits a fibrous ap-
pearance produced by vertical and parallel

fibres, with narrow fissures between, into
which the fibrous expansion which invests this
surface is implanted. The posterior surface
is articular and adapted to the trochlea of
the femur. A vertical ridge, which inclines a
little outwards in its descent, divides this sur-
face into two lateral portions ; each of these por-
tions is a concave articular facet for adaptation
to the anterior part of each condyle of the
femur, and consequently there is between these
surfaces the same inequality which exists be-
tween the condyles. In the recent condition
these surfaces are covered by a soft and very
elastic cartilage.

Structure and developement. — The patella
is entirely composed of cancellated texture,
the anterior surface being covered by a thin
lamella of very fibrous compact tissue already
referred to. This bone is developed by a single
point of ossification, which commences about
the second year.

The patella exists pretty generally among
Mammalia, also among Birds. It is most de-
veloped in the Pachydermata and the Solipeds,
and also in the Monotremata ; and least so in
the Carnivora and Quadrumana. It is absent in
Cheiroptera and Marsupiata.*

Leg. — The bones that form the second
segment of the inferior extremity are the
Tibia and Fibula.

Tibia, (shin-bone; Germ, das Schienbein.)
This bone is situated between the inferior ex-
tremity of the femur and the astragalus. Its
length is to that of the femur as five to six.
It forms the principal support of the leg, on
the inside of which it is placed, and its volume
is five times that of the fibula. After the
femur, it is the longest bone in the body, being
longer than the humerus.

The upper or femoral extremity of the tibia
is thicker and broader than the remaining parts
of the bone, and is properly the head of the
bone. Its transverse extent is much greater
than its antero-posterior. Its superior surface
presents two bony processes lying on the same
plane, denominated condyles of the tibia.
Each of these has upon its superior surface a
superficial concave articular facet, oval with long
axis from before backwards; to these surfaces
the term condyle has been improperly applied ;
but they are more correctly called the glenoid
cavities of the tibia, (cavitates glenoidete, ex-
terna et interna). These cavities correspond
to the condyles of the femur, having the semi-
lunar cartilages interposed; the outer cavity
approaches more to the circular form than the
internal one; it is likewise much less deep,
and at its posterior part it is even convex.
The internal one, on the other hand, is
uniformly concave, and its antero-posterior
axis greatly exceeds its transverse. These sur-
faces are separated in the centre by a pyra-
midal eminence whose apex appears bifurcated,
the subdivisions of which are separated by a
narrow rough space. This is the spine of the
tibia, (acdivitas intercondj/loidea ) ; it corres
ponds to the intercondyloid fossa of the femur

* Meckel, Anal. Compar.

EXTREMITY.

169

where the crucial ligaments are attached.
Anterior and posterior to this spine are two
rough depressions, the posterior more hollowed
than the anterior : into the former the posterior
crucial ligament is inserted, and the latter re-
ceives the anterior crucial ligament.

The circumference of the head is rough and
perforated by a vast number of minute vas-
cular foramina. Each condyle projects late-
rally beyond the plane of the corresponding
surface of the shaft, the internal to a greater
extent than the external. These lateral pro-
jections are distinguished by the name of Tu-
berosities. The internal tuberosity gives in-
sertion at its lower part to the internal lateral
ligament of the knee-joint; posteriorly this
tuberosity is grooved, and one of the tendons
of the semi-membranosus is inserted into the
groove, and separates the internal lateral ligament
from the bone in this situation. At the pos-
terior part of the external tuberosity there is a
small articular facet, nearly circular and plane,
with which the fibula is articulated.

In front of the head of the tibia there is a
rough triangular surface, the apex of which
is directed downwards and forms a promi-
nence, which is smooth at its superior part, but
rough inferiorly. The ligamentum patellae is
inserted in the latter situation; the smooth
portion indicates the position of a bursa which
intervenes between the ligament and the bone.
This prominence is called the anterior tube-
rosity, and by some anatomists the spine.
From the inferior rough portion of this tube-
rosity there passes upwards and outwards a
prominent line, most prominent at its ter-
mination, where the tibialis anticus muscle has
one of its attachments.

The shaft of the tibia has the form of a
triangular prism in almost its whole extent:
at its inferior third this form is less distinct,
in consequence of the angles being rounded off.
Of the three surfaces the anterior is that which
presents the greatest dimensions : it is smooth
and slightly convex in its entire extent, in-
clined backwards and inwards, subcutaneous,
except at its upper part, where an aponeurotic
expansion connected with the tendons of the
semi-tendinosus, sartorius, and gracilis muscles.
The inferior fourth of this surface is much
more convex than the upper portion, and looks
directly inwards. The external surface is in-
clined backwards and outwards, and is con-
cave in its three superior fifths, convex in the
rest of its extent. The depth of the superior
concave portion is proportionate to the de-
velopement of the tibialis anticus muscle, to
which it gives insertion. The inferior con-
vex portion is of less extent than the superior,
and as it descends it experiences a change of
aspect so as to look directly forwards. This
change is in accordance with the altered di-
rection of the tendons of the tibialis anticus
and extensor muscles of the toes, which lie in
contact with the bone in this situation. The
posterior surface is expanded at its extremities
and contracted in the centre. At its superior
part a triangular surface is marked off from
the rest, towards the upper extremity by an

oblique line, which proceeds from below up-
wards, and from within outwards; into this
line are inserted the poplitseus, soloeus, tibialis
posticus, and the long flexor muscle of the
toes. The space which intervenes between
this line and the posterior margin of the head
of the bone is covered by the poplitaeus muscle
and forms part of the floor of the popliteal
space. Immediately below this oblique line,
the orifice of the nutritious canal is situated,
penetrating the bone obliquely downwards;
this canal is the largest of the medullary canals
of the long bones ; and Cruveilhier states that
he has traced a nervous filament passing into
it in company with its artery. All that portion
of the posterior surface which is below the
oblique line is smooth and divided by a ver-
tical line, which is variously developed in dif-
ferent subjects; the tibialis posticus muscle
and the long flexor of the toes are attached to
this surface.

Three distinct edges separate these surfaces.
The anterior edge (crista tibia) is very promi-
nent and sharp in its three superior fourths, but
rounded off' below : in its upper part it is quite
subcutaneous, and may be felt under the skin.
The external edge forms a very distinct line of
demarcation between the internal and posterior
surfaces ; it gives attachment to the interosseous
ligament, and at its inferior extremity it bifur-
cates and encloses a concave triangular surface,
in which the fibula rests. The internal edge is
more rounded than either of the others ; more
distinct inferiorly than superiorly. At its up-
per end it gives insertion to the internal lateral
ligament of the knee-joint and the popliteus
muscle, and lower down to the solceus and the
common flexor of the toes.

The inferior or tarsal extremity of the tibia
is of larger dimensions than the shaft, although
much smaller than the superior. On its infe-
rior surface we notice a quadrilateral articular
cavity, of greater dimensions transversely than
from before backwards, concave in this latter
direction, and slightly convex transversely, in
consequence of the existence of a slight ridge in
the centre, which passes from before backwards.
This surface is for articulation with the supe-
rior part of the body of the astragalus to form
the ankle-joint.

The anterior surface of the inferior extremity
of the tibia is convex and rough ; it gives in-
sertion to the anterior ligamentous fibres of the
ankle-joint, and the tendons of the extensor
muscles pass over it. The posterior surface is
very slightly convex ; sometimes a very super-
ficial groove exists upon it for lodging the ten-
don of the flexor pollicis longus ; and internal
to that, and lying behind the internal malleolus,
a more distinct and constant groove, which
passes obliquely downwards and inwards, and
lodges the tendons of the tibialis posticus and
flexor communis.

On the inside of the inferior extremity, we
observe that the bone is prolonged downwards
and slightly inwards, forming a thick and flat-
tened process, quadrilateral in form, called
malleolus internus. The internal surface of
this process is rough and convex; it is quite

170

EXTREMITY.

subcutaneous; its external surface is smooth,
and exhibits a triangular articular facet,
which is united at a little more than a right
angle with the articular surface on the inferior
extremity of the tibia ; by this facet the internal
malleolus moves on the inner surface of the
body of the astragalus. The apex of the mal-
leolus has the internal lateral ligament of the
ankle-joint inserted into it ; the anterior edge
gives insertion to ligamentous fibres, and the
posterior edge, much thicker than the anterior,
is closely connected with the posterior surface
of the inferior extremity of the tibia, and has
upon it the oblique groove already referred to.
In comparing the position of the malleolus in-
ternus with that of the internal tuberosity of
the tibia, (which may best be done by laying
the bone on its posterior surface on a horizontal
plane,) it will be observed that the malleolus is
considerably anterior to the tuberosity, a feet
which is attributable to the same cause which
occasions the change of aspect in the inferior
part of each of the three surfaces of the shaft,
namely, a torsion of the bone similar to that
already noticed in the other long bones of the
extremities. This torsion is manifest at the
junction of the inferior and middle thirds, the
lower part having the appearance of being
twisted inwards, and the upper part outwards.
The outer side of the tarsal extremity of the
tibia is excavated so as to form a triangular
surface, rough in its entire extent, to which the
fibula is applied, and into which are implanted
the strong ligamentous fibres by which that
bone is tied to the tibia.

Structure. — The cancellated texture is accu-
mulated in large quantity at the extremities,
where, especially at the superior, a line is very
frequently apparent on the whole circumference,
indicating the place of junction of the epiphysis
and shaft. The medullary canal is large, ap-
proaching the cylindrical form, and surrounded
by a dense compact tissue.

Fibula (Fr.perone; Germ. Wadenbein). —
This bone is situated on the outer and posterior
part of the tibia. It is about the same length
as that bone, but as its upper extremity is ap-
plied to the under surface of the external tube-
rosity, its inferior extremity projects below that
of the tibia. There is a slight obliquity in its
direction, and in consequence, its inferior extre-
mity advances more forwards than its superior.

The fibula is a very slender bone in its
entire extent, however its extremities are a little
enlarged. The superior extremity or head of
the fibula (capitulum) is somewhat rounded on
its inner side, flattened on its external surface,
terminating superiorly in a point into which
the external lateral ligament of the knee-joint
is inserted, anterior and posterior to which the
edge of the bone receives the tendon of the
biceps muscle. At the upper and anterior
part of its internal surface there is a small sur-
face nearly plane, which is articulated with a
similar one on the external tuberosity of the
tibia. On the shaft of the fibula we may dis-
tinguish three surfaces, but in consequence of
the great extent to which the fibula appears to
have undergone torsion, it is at first difficult to

detect the lines of demarcation between these
surfaces* The external surface is very narrow
and convex in its upper third, gradually ex-
pands as it descends, and becomes hollowed
out in its middle third, where it receives the
peronoei muscles ; in both these portions the
aspect of this surface is outwards and slightly
forwards. In the inferior third it is quite flat,
and its aspect is outwards and backwards. The
internal surface has a longitudinal sharp ridge
upon it, which gives insertion to the interosse-
ous ligament. This crest divides the internal
surface into two portions; the anterior, very
small, in some cases not exceeding two or three
lines, gives attachment to the extensor muscles
of the toes and the peronaeus tertius ; the pos-
terior, much more considerable and slightly
concave longitudinally for about its two supe-
rior thirds, has the tibialis posticus inserted
into it. This surface, which above looks nearly
directly inwards, looks forwards in its inferior
third. The posterior surface is also very nar-
row above, and expands as it descends ; upon
it the twist in the bone is very obvious. In
its superior third this surface looks outwards
and backwards ; in its middle third, where it is
much more expanded, it looks directly back-
wards; and in its inferior third its aspect is
inwards, and here it terminates in forming a
rough surface which is adapted to the similar one
on the fibular side of the inferior extremity of
the tibia. Superiorly the posterior surface of the
tibia gives attachment to the solceus muscle, and
lower down to the flexor pollicis proprius. The
orifice of the nutritious canal, directed down-
wards and forwards, is found here.

A knowledge of the edges which separate
these surfaces will assist the student in
understanding the position of the surfaces
themselves. The anterior edge begins just
below the head, passes down in front of the
bone as far as the middle, then becomes exter-
nal and bifurcates, enclosing a triangular sur-
face on the outside of the inferior extremity of
the bone, which is quite subcutaneous. The
external edge is at first external, and about the
commencement of the inferior third it begins
to wind round so as ultimately to become
posterior. The internal edge, which is the
most acute, and is more prominent in the centre
than at its extremities, passes forwards inferiorly,
and terminates in front of the inferior extre-
mity of the bone : below it gives attachment
to the interosseous ligament.

The inferior extremity is long and flat, and
terminates in a point ; it extends entirely below
the inferior articular surface on the tibia, and,
as Cruveilhier aptly remarks, it forms exter-
nally the pendant to the malleolus internus,
which it exceeds in length and thickness ; it is
consequently called the malleolus externus.
The internal surface of the external malleolus
presents in its anterior two-thirds a plane
triangular surface for articulation with the
astragalus; behind this surface there is an
excavation, which is rough, and gives insertion
to the posterior external lateral ligament. The
external surface is convex and subcutaneous,
and the posterior surface is grooved for the

EYE.

171

passage of the tendons of the peronaei muscles.
The apex of the malleolus is directed down-
wards, and is the point of attachment of the
middle external lateral ligament.

Structure. — This bone is very light and
elastic, a property rendered necessary by the
antagonist muscles which are inserted into its
opposite surfaces. Its extremities are composed
of cancellated structure, which extends some
way to the shaft of the bone. The medullary
canal, very narrow and irregular, is found only
in its middle third.

Developement of the bones of the leg. — The
tibia begins to ossify somewhat earlier than the
fibula. Both bones begin to ossify in their
shafts ; the ossific point of the shaft of the tibia
appeal's about the middle of the second month.
According to Meckel, in the embryo of ten
weeks, the fibula is not above half the length of
the tibia; after the third month the two bones are
nearly equal. Both bones have an ossific point
for each extremity. The superior extremity of
the tibia begins to ossify towards the termination
of the first year after birth. The inferior extre-
mity is ossified in the course of the second
year : the external malleolus is a prolongation
of the inferior extremity. The union of the
extremities with the shaft commences by the
inferior, and is completed from the eighteenth
to the twenty-fifth year. The ossification of
the fibula follows nearly the same course,
excepting that the superior extremity does not
begin to ossify till the fifth year.

The tibia constitutes the principal pillar of
support to the leg. It is placed perpendicu-
larly under the femur, and as the latter bone
is inclined inwards, it follows that there must
be an angle formed between these two bones
at the knee-joint, a very obtuse one, with its
apex inwards.* It is then by the strength and
direction of the tibia that the leg firmly sup-
ports the body in the erect attitude ; the fibula
seems not to contribute at all to the solidity of
the limb, but is chiefly employed to increase the
surface of attachment for the muscles of the leg.

The developement of the tibia and fibula in
the inferior mammalia is pretty similar to that
of the radius and ulna. The tibia is always
fully developed, and, as in man, is the prin-
cipal bone of the leg, its size being pro-
portionate to the weight and strength of the
animal. Admitting the fibula to be the ana-
logue of the latter bone, we find that, as it
is rudimentary in the Solipeds and Ruminants,
so the fibula is in a similar condition in these
animals. In the former animals this bone is
applied to the external side of the head of the
tibia in the form of an elongated stilet, termi-
nating less than half way down in a fine point.
On the other hand, in Ruminants it is only the
inferior part of the fibula that is developed ; it
appears under the form of a small narrow bone,
extending a very little way upwards, and form-
ing the external malleolus.

* A preternatural obliquity of the femur causes
a corresponding divergence of the tibia from the
perpendicular. When the femur is directed un-
usually inwards, the tibia is directed downwards
and outwards.

In Pachydermata the fibula is fully deve-
loped and quite distinct from the tibia, and
very small in proportion. In Edentata the
two bones are fully developed, and in the
Sloths the inferior extremity of the fibula con-
tributes to form the articular surface for the
astragalus. In Rodentia the two bones are
united together in the inferior half, as also with
the Insectivora, particularly in the Mole. In
many Carnivora these bones are fully developed
and detached : this is particularly manifest in
the Phocidae and the Felidae. In the Dogsr
however, the fibula is attached to the posterior
part of the tibia.

For the description of the bones composing
the foot, we refer to the article under that
head; and for further details on the osseous
system of the extremities, we refer to the
articles OSSEOUS SYSTEM (Corap. Anat.) and
SKELETON.

Abnormal condition of the bones of the extre-
mities. — A congenital malformation of one or
more of the extremities is classed by Isidore
Geoffrey St. Hilaire among what he denomi-
nates " Monstres Ectromeliens," of which he
has three subdivisions: 1st, where the hands
or feet appear to exist alone, and seem to be
connected with the trunk without the inter-
vention of all or some of the intermediate
segments; these he denominates Phvcomeles,
(<puxv), Phoca, and /AE?U>?, membrum,} from their
resemblance to the permanent condition of the
aquatic mammalia : 2d, cases in which there
are one or more incomplete limbs terminating
in the form of stumps: to these he gives
the name Hemimeles: and, lastly, where the
limb or limbs are wholly absent or scarcely at
all developed. An interesting case of Phoco-
melia is recorded by Dumeril ; all the limbs-
were in this condition, owing to the absence
of the humerus, and forearm bones in the upper
extremity, and the presence of a very imperfect
femur, developed only as to the head and tro-
chanters, and a very imperfect tibia in the lower
extremity. The clavicle and scapula were pre-
sent, but presented some irregularities of form.*
The congenital absence of these last bones is-
rare excepting where the other bones of the
limb are also absent.

It would be inconsistent with the objects of
this article to prosecute this subject further ; we
therefore refer for further details to the article
MONSTROSITY.

For BIBLIOGRAPHY, see that of ANATOMY
(Introduction).

(R. B. Todd.)

EYE, (in human anatomy), opOaA/xo?, orga-
non vims ; oculus. Fr. (Eil ; Germ, das Auge ;
Ital.Orr hio. — The human eye is a hollow sphere,
about one inch in diameter, with a circular
aperture in the anterior part about one-fifth of
this sphere in breadth, filled by a transparent
convex portion called the cornea, through which
the light is transmitted. Within this hollow

* Bull, de la Soc. Philomath, t. iii., quoted in
Geoff. St. Hilaire 's Anom, de TOrganization, t. ii.
p. 211.

172

EYE.

sphere, and at a short distance behind the trans-
parent convex portion or cornea, is fixed a
double convex lens, called the crystalline lens
or crystalline humour; and between this cor-
nea and crystalline lens is interposed a parti-
tion or screen called the iris, with a circular
aperture in its centre called the pupil. The
inner surface of this hollow sphere, as well as
the back of the iris or screen, are covered or
stained with a black material. The space be-
tween the cornea and crystalline lens, in which
the iris is placed, is filled with a transparent
fluid, called the aqueous humour, and the
space between the crystalline lens and the bot-
tom of the sphere is filled with a similar fluid,
called the vitreous humour. The annexed figure
represents a section of this simple piece of opti-
cal mechanism, much larger than natural to
render the parts more distinct.

Fig. 100.

An acquaintance with the laws which regu-
late the transmission of the rays of light through
transparent bodies, and with the manner in
which the lenticular form changes the direction
of these rays, teaches that a correct image of ex-
ternal objects is formed in the bottom of the eye
in consequence of the above adjustment of its
parts. First, the rays of light acquire a con-
vergence in their passage through the cornea
and aqueous humour, then the central portion
of the pencil of rays is transmitted through the
pupil, and, finally, the rays in their passage
through the crystalline lens acquire such addi-
tional convergence, that they are brought to a
focus on the bottom as represented in the an-
nexed diagram.

Such are the essential component parts of
the eye, considered as a piece of optical me-
chanism, but viewed as a piece of anatomical
mechanism, its construction is much more com-
plicated, and the materials of which it is com-
posed are necessarily totally different from those
of any human contrivance of a similar nature.
It lives in common with the body of which it
forms a part, it grows and is repaired ; conse-
quently, the animal organisation destined for
such functions must constitute an essential
part of its construction.

The organ derives its permanent spherical
form, its external strength, and the support of
the delicate parts within it, from a strong opaque
membrane called the sclerotic coat; while
the convex portion, called cornea, in front,
equally strong, being transparent, allows the
rays of light to pass without interruption. The
interior of the portion of the sphere formed by
the sclerotic coat is lined throughout by a soft
membrane called the choroid, necessarily con-
stituting another hollow sphere, accurately
adapted and adhering to the inside of the for-
mer. This also has its circular aperture ante-
riorly, into which is fitted the screen called iris,
as the cornea is fitted into the aperture in the
sclerotic. While the external surface of this
choroid coat is comparatively rough and coarse
in its organization, as it adheres to the equally
coarse surface of the sclerotic, the interior is
exquisitely smooth and soft, being destined to
embrace the retina, another spherically dis-
posed membrane of extreme delicacy. The
screen called iris, which is fitted into the cir-
cular aperture anteriorly, is as different from
the choroid coat in its organization as the cor-
nea is from the sclerotic : it is perfectly plane,
and therefore forms with the concave surface
of the cornea a cavity of the shape of a plano-
convex lens, called the anterior chamber. In
or on the choroid coat the principal vessels and
nerves, destined to supply the interior of the
organ, are distributed, and in its texture and
upon its inner surface is deposited the black
material, which in this part of the chamber, as
well as on the back of the iris, is so essential a
provision. At the anterior margin the choroid
is more firmly united to the corresponding mar-
gin of the sclerotic by a circular band of pecu-
liar structure called the ciliary ligament, and on
its inner surface, in the same place, it is fur-

Fig. 101.

EYE.

173

nished with a circle of prominent folds called
ciliary processes, by means of which it is united
to the corresponding surface of the hyaloid
membrane of the vitreous humour. The an-
nexed figure represents a section of this hollow
sphere lodged within the sclerotic sphere. The
external circle, a «, between the two black
lines represents a section of the strong opaque
membrane called the sclerotic, which consti-
tutes the case or resisting sides of the organ ;
b is the transparent lenticular window called
cornea, which fills the aperture left in the ante-
rior part of the sclerotic for its reception ; d d is
the place of union between the sclerotic and
cornea, to which the ciliary ligament on the
outside of the anterior margin of the choroid
sphere corresponds; e e the circle bounded
by the line marking the inner surface of the
sclerotic externally, and by the shaded part in-
ternally, represents a section of the hollow
sphere called choroid. At the point d d, cor-
responding to the place of union between the
sclerotic and cornea, this choroid projects exter-
nally, encroaching upon the sclerotic in a pecu-
liar manner, to be presently described as the
ciliary ligament; while at the same point it
projects internally in the shape of a series of
folds, to be described as the ciliary processes.
The white productions extending from the same
points in a vertical direction into the chamber
of the aqueous humour, between the cornea and
crystalline lens, represent a section of the
screen called the iris, f is a section of the
crystalline lens.

Fig. 102.

ed by the cornea being very small, and that
behind bounded by the retina being very large.
This large posterior chamber is distended by a
spherical transparent mass, called the vitreous
humour, which does not, however, fill this pos-
terior chamber completely, but is discontinued
or compressed at a short distance behind the
iris, leaving a narrow space between it and that
membrane, called the posterior chamber of the
aqueous humour. This spherical mass is of ex-
tremely soft consistence, and is composed of a
delicate transparent cellular membrane called
the hyaloid membrane, the cells of which are
distended with a transparent fluid. In the
small space between the anterior part of the
vitreous humour and the back of the iris, called
the posterior chamber of the aqueous humour,
and lodged in a depression formed for its re-
ception in the vitreous humour, is placed the
double convex lens called the crystalline lens.
The relation of these parts to each other may
be seen in the last figure, and the one below
represents the optic nerve expanded in the
form of a spherical membrane over the sphere
of vitreous humour, with the crystalline lens
lodged in a depression on the anterior part of
that sphere, and surrounded by a circle of
radiating lines, which are delicate folds corres-
ponding to the folds of the choroid, called the
ciliary processes.

Fig. 103.

Through a small aperture in the sclerotic
and choroid membranes in the bottom of the
eye, the optic nerve is transmitted, and imme-
diately expands into a texture of the most ex-
quisite delicacy, called the retina. This con-
stitutes a third spherically disposed membrane,
not however of the same extent as the sclerotic
or choroid, being discontinued at a distance of
about an eighth of an inch from the anterior
margins of these membranes. This is the ner-
vous expansion endowed with the peculiar
description of sensibility which renders the ani-
mal conscious of the presence of light. The
globe of the eye, as above described, is ob-
viously divided by the iris into two chambers of
very unequal dimensions ; that in front bound-

The piece of animal optical mechanism thus
constructed is lodged in an open cavity of the
skull called the orbit, and is furnished with six
small muscles for its motions inserted into the
outside of the sclerotic coat. The transparent
cornea through which the light is transmitted is
necessarily exposed, and not being in its nature
suited to such exposure, is covered with a
membrane called conjunctiva, which also extends
over the sclerotic, where that membrane con-
stitutes the anterior part of the globe, and then
being reflected, lines the eyelids, and finally be-
comes continuous with the skin of the face.

The human eye is, as has been stated above,
probably a sphere of about one inch in diameter.
Petit, however, who appears to have first made
the attempt to determine the proportions of the
organ accurately, describes the axis to be to the
diameter as 135 to 136, and the younger Sb'm-
merring, apparently from his own observations,
as 10 to 9.5. This belief in a slight differ-
ence in dimension may, however, have been

174

EYE.

adopted from not making allowance for the
projection of the cornea, which is a portion of
a smaller sphere than the globe itself, and con-
sequently projects beyond its circumference.
From the flaccid state of the eye even shortly
after death, it must be very difficult to measure
it accurately. The question is, however, for-
tunately of little practical importance. The
eyeball of the male is generally a little larger
than that of the female; and if a close inquiry
be made into the matter, much difference in this
respect might probably be detected in different
individuals. I have seen the eyeball in an
adult of full size not larger than that of a child
of five years old ; and there is much apparent
difference in consequence of the difference in
the depth of the orbit, and in the gape of the
eyelids. Although the human eyeball is nearly
a perfect sphere, that precise form is obviously
not an essential requisite in the construction of
a perfect organ of vision. In all the vertebral
animals the bottom of the eye, where the retina
is expanded, is probably a portion of a correct
^sphere, but in many the anterior part is com-
•pressed, or in other words the sphere is trun-
cated, to adapt it to the form and dimensions of
the head, or to bring the cornea and lens nearer
4o the retina. In the mysticete whale the axis
as to the diameter as 20 to 29 ; in the swan as
7 to 10 ; in the turtle as about 8 to 10 ; and in
the cod as 14 to 17. This deviation from the
>spherical form demands a corresponding provi-
sion in the construction of the sclerotic, to be
•noticed when describing that membrane. For
;a fuller account of the comparative proportional
measurements of the eye, the student is referred
to the works of Cuvier and D. W. Sommer-
ring, as quoted at the end of this article ; the
limits of which do not admit of a greater detail
»of facts derived from comparative anatomy
than the illustration of the description of the
human organ absolutely demands.

Having attempted to give a general notion
of the mechanism of the eye in the preceding
paragraphs, it remains to consider each com-
ponent part separately, and to determine its
organization, properties, and application, as
well as the changes to which it is liable from
age, disease, or other circumstances.

Of the sclerotic membrane. — This, as has
been stated, constitutes, with the transpa-
rent cornea, the external case upon which
the integrity of the more delicate inter-
nal parts of the organ depends, otherwise in-
capable of preserving their precise relations to
each other : without such support the compo-
nent structures must fall to pieces, or be crushed
by external pressure. The name is derived
from the Greek <rxfa)qou, and it has also been
called cornea and cornea opaca in contradistinc-
tion to the true or transparent cornea, a structure
to which it bears no resemblance whatsoever ;
it is the same animal material which exists in
all parts of the body where strength with flexi-
bility is required, the material which in modern
times has been denominated fibrous mem-
brane. When carefully freed from all ex-
traneous matter by clipping with a pair of
scissors under water, it presents the brilliant
silvery-white appearance so characteristic of

the fibrous membranes. The white streaks
which give the fibrous appearance appear ar-
ranged concentrically as the lines on imper-
fectly polished metallic surfaces. It is inelastic
as other fibrous membranes, and so strong that
it does not tear or yield unless exposed to the
greatest violence. Although penetrated by the
vessels going into and returning from the in-
ternal parts of -the eye, it does not appear to
have much more red blood circulating through
its texture than other tendinous expansions
distinguished for their whiteness. The vas-
cularity of the anterior part, however, where it
is exposed in the living body, constituting the
tunica albuginea, or white of the eye, is
different from that of. the rest of the mem-
brane. The four straight muscles are pene-
trated by small branches of the ophthalmic
artery, the delicate ramifications of which con-
verge to the circumference of the cornea, for
the nutrition of which membrane they appear
to be destined. In the natural state they can
scarcely be detected, but when enlarged by in-
flammation, present a remarkable appearance,
considered by practical writers one of the most
characteristic symptoms of inflammation of the
eyeball, or, as it is called, iritis. They then
appear as numerous distinct vessels, and as they
approach the margin of the cornea, become so
minute and subdivided, that they can no longer
be distinguished as separate vessels, but merely
present a uniform red tint, described as a pink
zone. The colour of this inflammatory vascula-
rity is also characteristic. Whether from the
vessels being more arterial than venous, or
from their distribution in so white a structure,
they present a brilliant pink appearance very
different from the deep red of conjunctival in-
flammation, which often enables the practi-
tioner to pronounce an opinion as to the nature
of the disease before he makes a close examin-
ation.

The inner surface of the sclerotic where it
is in contact with the choroid, does not present
the same brilliant silver-white appearance that
it does externally, being stained with the black
colouring matter ; it is also obscured by a thin
layer of cellular membrane, by means of which
it is united to the external surface of the cho-
roid.* This layer of cellular membrane was
described by Le Cat, and more particularly by
Zinn, as a distinct membrane, and considered
to be a continuation of the pia mater ; it is, how-
ever, obviously nothing more than the connect-
ing material applied here as in other parts of
the body where union is requisite.

The thickness of the sclerotic is greater in
the bottom of the eye than at its anterior part,
where it is so thin that it allows the black colour
of the choroid to appear through it, giving to this
part of the eye a blue tint, particularly remark-
able in young persons of delicate frame. The at-
tachments of the four straight muscles, how-
ever, appear to increase the thickness in this

* [Arnold and others describe and figure a serous
membrane in this situation ( Spinnwebenhaut , arach-
noidea oculi ). See the figure of a vertical section
of the eye in Arnold liber das Auge, tab. iii. fig. 2,
and couied into Mr. Mackenzie's work on the
Eye.— ED.]

EYE.

175

situation ; but that there is no general thick-
ening in this part from this cause is proved
by the thinness of the membrane in the inter-
vals between and beneath these tendons. The
consequence of this greater thinness of the
membrane anteriorly is, that when the eyeball
is ruptured by a blow, the laceration takes
place at a short distance from the cornea. In
animals in whom the eyeball deviates much
from a true sphere, as in the horse, ox, sheep,
and above all, in the whale, the sclerotic is
much thicker posteriorly than anteriorly, being
in the latter animal from three quarters to an
inch in thickness, while it is not more than a
line at its junction with the cornea. The rea-
son for the existence of this provision is, that
the form of the perfect sphere is preserved by
the uniform resistance of the contents, but when
these contents are spherical in one part, and
flattened in another, the external case must pos-
sess strength sufficient to preserve this irregu-
larity of form. It is remarkable that this
strength is conferred in the class mammalia
by giving to the sclerotic increase of thickness,
the fibrous structure remaining nearly the same
in its nature, while in birds, reptiles, and fishes,
the requisite strength is derived from the pre-
sence of a cartilaginous cup or portion of sphere,
disposed within a very thin fibrous sclerotic.
This cartilaginous sclerotic, as it is often-
called in the books, exists, as far as 1 have been
able to ascertain, in these three classes, and is in
some individuals very remarkable. In birds it
is thin and flexible, giving a degree of elasticity,
which distinguishes the eyeball in this class.
In fishes, as has been observed by Cuvier and
others, the cartilage is always present, and is
particularly thick in the sturgeon ; it is even
osseous in some, as the sea-bream, from the
eye of which animal I have often obtained it
in the form of a hard crust by putrefactive
maceration. Among the reptiles the turtle
presents a good example of this structure.
Where the deviation from the spherical form is
very great, as in birds, additional provision is
made to sustain the form of the organ. This
consists of a series of small osseous plates ar-
ranged in a circle round the margin of the cor-
nea, lapping over each other at the edges, and
intimately connected with the fibrous and car-
tilaginous layers of the sclerotic. A similar
provision exists in the turtle, and also in the
chameleon, and m£ny other lizards, but not
perhaps so neatly and perfectly arranged as in
birds. It is found in the great fossil reptiles
Ichthyosaurus and Plesiosaurus.

The sclerotic, like other fibrous membranes,
being inelastic and unyielding, does not be-
come stretched when fluids accumulate in the
eyeball in consequence of inflammation, or in
other words, the eyeball does not become en-
larged from effusion of serum or secretion of
purulent matter into its chambers. To this
probably may be attributed the intolerable
torture and sense of tension experienced when
the eyeball suppurates, as well as the severe
pain extending to the temple in some forms of
inflammation. The pain in such cases must
not, however, be wholly attributed to this dis-
tension of an unyielding membrane. The

fibrous membranes in general, when affected by
rheumatic or arthritic inflammation, become
acutely sensible, and the cause of much suffer-
ing ; and the sclerotic, when similarly affected,
acquires the same description of painful sen-
sibility, apparently independent of distension
from effusion. In certain forms of inflam-
mation and other morbid changes of the
eyeball, the sclerotic appears to yield to
distension, as in scrofulous inflammation and
hydrophthalmia ; but this is not a mechanical
stretching, but an alteration in structure at-
tended with a thinning of the membrane, and
consequent alteration in the shape of the globe.
It appears that the cornea and sclerotic are
peculiarly, if not in many instances almost ex-
clusively, the seat of the disease in chronic
scrofulous inflammation of the eyeball. This
inference may, I think, be justly drawn from
the fact, that in such cases the sclerotic becomes
so much thinned that the dark choroid projects,
in the form of a tumour, and the eye loses its
spherical form ; yet the pupil remains regular,,
the lens transparent, and the retina sensible to
light. When the cornea is destroyed by slough
or ulceration in severe ophthalmia, allowing
the lens and more or less of the vitreous hu-
mour to escape, the sclerotic does not accom-
modate itself to the diminished contents by a
uniform contraction, but merely falls in ; and
when the eye has been completely emptied, it
is found many years after the injury folded up
into a small irregular mass in the bottom of the
orbit. When the organization of the eye is
completely destroyed by idiopathic, rheumatic,
or syphilitic inflammation, the sclerotic becomes
flaccid, and the whole eyeball soft, allowing
the contraction of the four straight muscles to
produce corresponding depressions, and thus
convert the sphere into a form somewhat cu-
bical.

Of the cornea. — This is the transparent body
which fills the circular aperture in the anterior
part of the spherical sclerotic ; it is called cornea
from its supposed resemblance to transparent
horn, and cornea transparens in contradistinction
to the sclerotic, which, as has been stated, is
called cornea opaca. It is generally described
as a transparent structure, serving to the eye the
same purpose as the crystal to the watch ; but
this is not a correct comparison : the crystal
merely transmits the light without changing
the direction of the rays ; the cornea, whether
it be considered in itself a lens, or as the sphe-
rical surface of the aqueous humour, refracts
the rays and causes them to converge to a
focus. Haller, although he does not directly
say that it is a lens, yet states that if held over
a book it magnifies the letters, which of course
results from its lenticular form; and Cuvier
and Biot distinctly call it a meniscus. On the
other hand, the Sommerrings, both father and
son, describe it as a mere segment of a sphere,
the curve of the convexity corresponding to
that of the concavity, as in the watch crystal.
I consider it to be a lens and, a meniscus. If
it be removed from the eye a short time after
death with a portion of the sclerotic, and dipped
in water to smooth its surfaces, it magnifies ob.
jects when held between them and the eye, as

176

EYE.

stated by Haller; and sections of the cornea of
the eye of the horse, ox, sheep, or other large
animals, shew that the part is much thicker in
the centre than at the circumference. It is
also to be observed that it has the same provi-
sion for the preservation of its lenticular form
in a correct state as the crystalline lens, as will
presently be explained. The statements made
by authors respecting the measurements of
the curvatures of the surface of the cornea can
be considered only as an approximation to the
truth. It is obvious that there must be much
difficulty in accurately ascertaining the matter
during life, and after death the form is so
speedily altered by evaporation that the curve
cannot remain the same as during life, hence
the measurements differ. Haller says it is a
portion of a sphere seven lines and a half
in diameter; Wintringham that the chord is
equal to 1.05 of an inch, the versed sine of
this chord 0.29, and consequently the radius is
equal to 0.620215 of an inch. Mr. Lloyd, in
his Optics, states, on the authority of Chossat,
that the surface of the cornea is not spherical
but spheroidical. He says, " the bounding
surfaces of the refracting media, however, are
not spherical but spheroidical. This remark-
able fact was long since suspected by M. Petit,
but of late has been placed on the clearest
evidence by the accurate measurements of
Chossat. This author has found that the
cornea of the eye of the ox is an ellipsoid of
revolution round the greater axis, this axis
being inclined inwards about 10°. The ratio
of the major axis to the distance between the
foci in the generating ellipse he found to be
1.3; and this agreeing very nearly with 1.337,
the index of refraction of the aqueous humour,
it follows that parallel rays will be refracted to
a focus by the surface of this humour with ma-
thematical accuracy." Whether we consider
the cornea as a distinct lens, or as constituting
the spherical surface of the aqueous humour,
there can be no doubt of its importance as an
agent in causing the convergence of the rays of
light to a focus on the retina in conjunction
with the crystalline lens. If other proof were
wanted, it is afforded by the comparatively
perfect optical mechanism of the eye after the
crystalline lens has been removed by the opera-
tion for cataract. The vision in such cases,
especially in young persons, is often so good
that individuals are satisfied with it for the
common purposes of life, and do not resort to
the use of the usual convex glasses. The cir-
cumference of the cornea is not perfectly cir-
cular externally, although it is internally; the
sclerotic laps a little over it both superiorly and
inferiorly, so that it appears a little wider than
it is deep, the vertical being to the horizontal
diameter as fifteen to sixteen.

Although the cornea is in general description
considered a simple and uniform membrane,
it is undoubtedly composed of three forms of
animal structure, as different from each other as
any other three in the animal. These are the
conjunctiva, which constitutes the exposed sur-
face; the proper cornea, upon which the
strength of the part depends ; and the elastic
cornea, which lines the inner concave surface.

The conjunctiva is evidently a continuation of
the skin, which, reflected in the form of a vas-
cular membrane, lines the eyelids, from which
it is continued as a delicate transparent mem-
brane over the anterior part of the globe, ad-
hering loosely to the sclerotic, and closely to
the cornea. The existence of conjunctiva on
the surface of the cornea proper admits of easy
demonstration, and its identity of character
with the rest of the conjunctiva and skin of
satisfactory proof. If the surface, shortly after
death, be scraped with the point of a needle,
the soft texture of the conjunctiva is easily torn
and detached, and the tough, firm, polished
surface of the cornea proper exposed; and if
the eye be allowed to remain for forty-eight
hours in water, the whole layer may by a little
care be turned off in the form of a distinct
membrane. During life, patches of the con-
junctiva are frequently scraped off by accident,
or by the point of the needle of the surgeon as
he attempts to remove foreign bodies implanted
in the cornea proper; it is also occasionally ac-
cidentally removed by lime or other escharotics.
When the vessels of the conjunctiva over the
sclerotic become enlarged, and filled with red
blood in consequence of preceding inflamma-
tion, that over the cornea at length becomes
equally red, and has its transparency greatly
impaired by the vascular ramifications. In
pustular ophthalmia, the pustules form on the
conjunctiva over the cornea as well as on that
over the sclerotic ; and in small-pox, vision is
frequently destroyed by this part of the tegu-
mentary membrane participating in the general
disease. In cases where the surface is con-
stantly exposed to the atmosphere in conse-
quence of prominent staphyloma or destruc-
tion or eversion of the eyelids, the conjunctiva
of the cornea occasionally becomes covered
with cuticle in common with the rest of the
membrane. In animals over whose eyes the
skin is continued without forming eyelids, the
continuity of it over the cornea is obvious. In
the mole-rat (Aspalax zemni.), where the skin
is uninterruptedly continued over the eye, the
hairs grow from the part over the cornea as
well as from the rest. When snakes cast their
covering, the cuticle is detached from the
cornea as well as from the rest of the body ;
and when the skin is drawn off the body of an
eel, it is detached with equal ease from the
cornea as from the rest of the eye.

The cornea proper, upon which the strength
of this part of the eye depends, is the structure
to which the appellation cornea is generally
exclusively applied ; it is, as might very rea-
sonably be expected from the office which it
performs, a material of peculiar nature and
organization, not identical with any other of
the simple membranes. During life, and
before it becomes altered by the changes which
take place after death, it is perfectly trans-
parent, colourless, and apparently homoge-
neous. This perfect transparency, however,
depends upon the peculiar relation of the
component parts of its texture, for if the eye-
ball of an animal recently dead be firmly
squeezed, the cornea is rendered completely
opaque, by altering that relation of parts, and

EYE.

177

as speedily recovers its transparency upon the
removal of the pressure. The chemical com-
position of the cornea is similar to that of the
fibrous membranes in general and the sclerotic
in particular : like the latter structure, it is con-
verted into gelatine by boiling ; but Berzelius
states that it contains also a small quantity of
fibrine or coagulated albumen, as proved by
the formation of a precipitate upon adding the
cyanuret of ferro-prussiate of potass to acetic
acid, in which the membrane has been digested.
The cornea possesses great strength, being
seldom or never ruptured by blows on the eye-
ball, which frequently tear the sclerotic exten-
sively. It does not yield to distension from
increased secretion, effusion, or suppuration
within the eyeball in consequence of inflam-
mation, but it becomes extended and altered
by growth both in shape and dimensions, as
may be observed in prominent staphyloma,
hydrophthalmia, and that peculiar alteration
called staphyloma pellucidum, in which the
spherical form of the membrane degenerates
into a cone, but retains its transparency.

The cornea is destitute of red vessels, yet it
affords a signal example of colourless and
transparent texture possessing vital powers
inferior to no other. No structure in the body
appears more capable of uniting by the first
intention. The wound inflicted in extracting a
cataract is often healed in forty-eight hours, yet
the lips are bathed internally with the aqueous
humour, and externally with the tears. Ulcers
fill up and cicatrize upon its surface ; and al-
though the vessels, under such circumstances,
frequently become so much enlarged as to
admit red blood, yet there can be no doubt
that ulcers do heal without a single red vessel
making its appearance. Abscesses form in the
cornea, and contain purulent matter of the
same appearance as elsewhere ; they are gene-
rally said to be between the layers of the
cornea, but they are evidently distinct cavities
circumscribed by the inflammatory process as
in other cases; occasionally, however, the
whole texture of the cornea becomes infil-
trated with purulent matter, as the cellular
membrane in erysipelas. The rapidity with
which this membrane is destroyed by the ul-
cerative process is another proof of its superior
vitality. In a few days a mere speck of ulce-
ration, the consequence of a pustule, extends
through the entire thickness, and permits the
iris to protrude; and in gonorrhffial and infantile
purulent ophthalmia, the process is much more
rapid and extensive. It is true that in the
latter case the destruction is attributed to gan-
grene or sloughing, and to a certain extent
correctly; but an accurate observer must admit
that the two processes co-operate in the pro-
duction of the lamentable consequences which
result from these diseases. Ulcers of the cornea
fill up by granulation and cicatrize as in other
parts of the body, but the repaired part does
not possess the original organization, and is
consequently destitute of that transparency and
regularity of surface so essential for its func-
tions; hence the various forms and decrees of

VOL. II.

opacity enumerated under the technical titles
of albugo, leucoma, margarita, nebula, &c.
which are probably never remedied, however
minute they may be, notwithstanding the ge-
neral reliance placed in the various stimulating
applications made for this purpose. Slight
opacities, or nebula; as they are called, if con-
fined to the conjunctival covering of the cornea,
gradually disappear after the inflammation sub-
sides, as does also diffused opacity of the
cornea itself, the consequence of scrofulous
inflammation; but I believe opacities from
ulceration and cicatrix are seldom if ever re-
moved. The effect of acute inflammation is
to render this, and perhaps all transparent and
colourless membranes, white and opaque with-
out producing redness; this may be seen in
wounds, where the edges speedily become
gray ; and in the white circle which frequently
occupies the margin of the cornea in the in-
flammations of the eyeball commonly called
iritis.

The cornea in a state of health is destitute
of sensibility. Of this I have frequently sa-
tisfied myself by actual experiment in cases of
injury of the eye, where the texture of the part
is exposed. When foreign bodies, such as
specks of steel or other metals, are lodged in
its structure, the surgeon experiences much dif-
ficulty in his attempts to remove them, from
the extremely painful sensibility of the con-
junctiva as he touches it with his needle ; but
the moment he strikes the point of the instru-
ment beneath the foreign body into the cornea
itself, the eye becomes steady, and he may
touch, scrape, or cut any part of the membrane
uncovered by conjunctiva without complaint.

It has already been stated that the cornea,
as it constitutes the transparent medium for
the passage of the rays of light, is composed of
three distinct forms of structure altogether dif-
ferent from each other, the conjunctiva, the
cornea proper, and the elastic cornea. The
latter membrane is now to be described. In
many of our books this membrane is vaguely
alluded to as the membrane of the aqueous
humour ; but with this it must not for a mo-
ment be confounded. It is a distinct provision
for a specific purpose, totally different from
that for which the other is provided. It was
known to and described by Duddell, Decemet,
Demours, and latterly by Mr. Sawrey ; but all
these authors having unfortunately published
their accounts in separate and probably small
treatises, not preserved in any journal, I have
not been able to consult them. It is, however,
distinctly recognized by Clemens, D. W.
Sommerring, Blainville, and Hegar ; and in a
paper on the anatomy of the eye in the Me-
dico-Chirurgical Transactions, I endeavoured to
direct attention to it without effect. The struc-
ture here alluded to is a firm, elastic, exqui-
sitely transparent membrane, exactly applied to
the inner surface of the cornea proper, and se-
parating it from the aqueous humour. When
the eye has been macerated for a week or ten
days in water, by which the cornea proper is
rendered completely opaque, this membrane re-

N

178

EYE.

tains its transparency perfectly ; it also retains
its transparency after long-continued immersion
in alcohol, or even in boiling water. When
detached, it curls up and does not fall flaccid
or float loosely in water, as other delicate mem-
branes. It also presents a peculiar sparkling
appearance in water, depending upon its greater
refractive power ; in fact it presents all the
characters of cartilage, and is evidently of pre-
cisely the same nature as the capsule of the
crystalline lens. When the cornea proper is
penetrated by ulceration, a small vesicular trans-
parent prominence has been repeatedly ob-
served in the bottom of the ulcer, confining for
a time the aqueous humour, but ultimately
giving way, and allowing that fluid to escape,
and the iris to prolapse; there can be little
doubt that it is this membrane which presents
this appearance. In syphilitic iritis, this mem-
brane becomes partially opaque, appearing
dusted or speckled over with small dots altogether
different in appearance from any form of
opacity observed on the conjunctiva or cornea
proper. When it has been touched by the
point of the needle in breaking up a cataract,
an opacity is produced closely resembling cap-
sular cataract. There is no difficulty in pre-
paring and demonstrating this membrane in the
eye of the sheep, ox, and especially the horse,
and it may with a little care be exhibited in the
human and other smaller eyes. The eye of
a horse having been macerated in water for six
or eight days, or until the cornea proper be-
comes white, should be grasped in the left hand
so as to render the anterior part plump, and
then inserting the point of a sharp knife into
the structure of the cornea at its junction with
the sclerotic, layer after layer should be gra-
dually divided by repeated touches round the
circumference, until the whole thickness is cut
through and the transparent elastic cornea ap-
pears, after which the cornea proper may be
turned off by pulling it gently with the forceps.
The use of the elastic cornea does not appear
to me doubtful. The crystalline lens is lodged
in a capsule of precisely the same nature, evi-
dently destined to preserve correctly the curva-
ture of each surface of that body, a condition
obviously necessary to secure the perfection of
the optical mechanism of the organ. The
elastic cornea in the same way, by its firmness,
resistance, and elasticity, preserves the requi-
site permanent correct curvature of the flaccid
cornea proper.

The cornea proper is closely and intimately
connected to the sclerotic at its circumference.
There does not appear to be any mechanical
adaptation resembling the fitting of a watch-glass
into the bezel, as stated in books ; but a ming-
ling of texture, as in many other instances in the
body. The two structures cannot be separated
without anatomical artifice and much vio-
lence. If the eye be macerated in water for a
month, and then plunged into boiling water,
the cornea may be torn from the sclerotic ; but
these destructive processes prove little with re-
gard to animal organization. The conjunctival
•overing of the cornea is, as has been .already

stated,continuous with the rest of the conju nctiva,
and the elastic cornea is continued for a short
distance beneath the sclerotic, as if slipped in
between it and the ciliary ligament.

The cornea, thus composed of three different
structures, varies in appearance at different
periods of life. In the foetus at birth it is
slightly cloudy, and even of a pinkish tint, as
if it contained some red particles in its blood ;
this is, however, more apparent on examination
after death than during life ; it is also thicker
in its centre. In old age it is harder, tougher,
and less transparent than in youth, and fre-
quently becomes completely opaque at its cir-
cumference, presenting the appearance denomi-
nated in the books arcus seniiis. How far the
alteration in the power of adaptation to distance,
which occurs in advanced life, is to be attri-
buted to change in curvature of the cornea, is
not settled.

If the foregoing account be correct, the ap-
parently simple transparent body which fills the
aperture in the anterior part of the sclerotic, is
composed of three distinct varieties of organic
structure, liable to changes from disease equally
distinct and varied. When the aqueous hu-
mour becomes the subject of description, I
will endeavour to shew that there is good rea-
son for believing that a fourth may be added to
these three, the membrane which lines the
chamber in which this fluid is lodged, and by
which it is secreted. Let it not be supposed
that this division of an apparently simple piece
of organization into so many distinct parts, is
merely an exhibition of minute anatomical re-
finement. The distinction is essentially neces-
sary to enable the surgeon to account for the
appearances produced by disease in this part,
and to guide him in the diagnosis and treat-
ment.

Of the choroid coat. — This membrane has
been so called from its supposed resem-
blance to the chorion of the gravid uterus;
it has also sometimes been called uvea from
its resemblance to a grape, a term, however,
which is now more frequently applied to the
iris. It has already been stated that the
spherical external case of the eye called the
sclerotic embraces another spherically disposed
membrane, called the choroid coat, accurately
fitted and adhering to it throughout. This
spherically disposed membrane has also its cir-
cular aperture anteriorly, into which is fitted
the screen or diaphragm called the iris. This
choroid membrane cannot be considered essen-
tial to the perfection of the organ considered
merely as a piece of optical mechanism, as a
spherical camera obscura, but is obviously an
important part of its anatomical organization,
and an essential provision for the perfection of
its vital functions. It appears to be destined to
secure the requisite mechanical connexion be-
tween the coarser and more rigid sclerotic case
and the parts within, as well as to secure these
delicate parts in their situation, and preserve
their form, at the same time affording a me-
dium for the distribution and support of the
vessels and nerves.

EYE.

This membrane is of a deep brown or black
colour, being stained with the colouring matter
called the black pigment; but when this is
removed, it exhibits a high degree of arterial
and venous vascularity. Its external surface
is comparatively rough, coarse, and flocculent,
and obscured by the cellular membrane which
connects it to the sclerotic. The inner surface,
which is in contact with the retina, presents a
very different appearance. It is soft and smooth,
and when minutely injected, resembles the
more delicate mucous membranes, and exhibits
a remarkable degree of minute villous vascu-
larity. The external surface being composed
of the larger branches of arteries, veins, and
nerves, may be torn away from the soft, smooth,
and more closely interwoven inner layer, or
the inner layer may be partially dissected up
from it, with some care, especially in the eyes
of the larger quadrupeds. This manoeuvre
having been executed by Ruysch, and prepara-
tions so formed displayed by him, the inner
layer has been denominated the tunica Ruys-
chiana. But this is a mere anatomical artifice.
There is no natural division into two layers,
the soft, smooth, and highly vascular inner
surface being formed by the ultimate subdivi-
sion and distribution of the larger branches of
vessels, which exhibit themselves separately on
the outside. It is a condition somewhat analo-
gous to that of the skin, where the soft, smooth,
villous external surface presents so remarkable
a contrast to the rough internal surface with its
layer of cellular membrane uniting it to the
subjacent parts.

The choroid is supplied with blood from the
ophthalmic artery by the short ciliary arteries,
which penetrate the sclerotic at a short distance
from the entrance of the optic nerve, and are
distributed to it in nearly twenty small branches.
These branches ramify and inosculate freely on
the outside of the membrane, and are visible as
distinct vessels, especially on the posterior part
of the sphere. They finally terminate on the
inner surface, forming a beautiful vascular
expansion. The long ciliary arteries give
scarcely any twig to the choroid, being distri-
buted to the iris, and the anterior branches
furnished to the sclerotic, as described in
speaking of that membrane, do not penetrate
to the choroid. The veins of the choroid pre-
sent a peculiar appearance. The ramifications
are arranged in the form of arches or portions
of a circle, bending round to a common trunk
like those of certain trees with pendulous
branches. They discharge their blood into
four or five larger branches which penetrate
the sclerotic at nearly equal distances from each
other behind the middle of the eyeball. On
account of this peculiar arrangement they have
received the name of vasa vorticosa. They lie
external to the ciliary arteries, but the ultimate
ramifications pervade the inner surface in the
same manner as the arteries ; and if the venous
system of the eye he minutely injected, the
same beautiful uniform villous vascularity is
displayed as in the arterial injections.

The annexed figure is a copy of Zinn's re-
presentation of the vasa vorticosa.

179

i. 104.

The numerous nerves which pierce the scle-
rotic and run forward between that membrane
and the choroid, called ciliary nerves, being
distributed almost exclusively to the iris, are
to be noticed when that organ is described ;
small branches of them are, however, probably
distributed to the choroid and its appendages,
and possibly even to the retina and hyaloid
membrane.

The inner villous surface of the choroid,
which in man is stained with the black pig-
ment, in several other animals presents a bril-
liant colour and metallic lustre. This is called
the tapetum. It is not a superadded material nor
dependent on any imposed or separable colour-
ing matter, but is merely a different condition
of the surface of the choroid or tunica Ruys-
ch iana, by means of which rays of light of a
certain colour only are reflected. It exists in
the form of a large irregular patch, occupying
the bottom of the eye toward the outside of
the entrance of the optic nerve. It is of a
beautiful blue, green, or yellow colour, with
splendid metallic lustre, and sometimes white
as silver. It is not obscured by the black
pigment which covers the rest of the surface
and even encroaches a little on its margin, and
consequently it acts most perfectly as a concave
reflector, causing the rays of light previously
concentrated on the bottom of the eye by the
lens to be returned, and to produce that re-
markable luminous appearance observed in the
eyes of cats and other animals when seen in
obscure situations. This provision is absent in
man, the quadrumanous animals, bats, the
insectivorous order, perhaps all the rodentia, the
sloths and many other of the class mammalia ;
while it is present in the majority if not all of
the ruminants, as well as in the horse, the
cetacea, and most of the carnivorous tribe. It
does not appear to exist in birds or reptiles,
and is absent in the osseous, although present
in the cartilaginous fishes. I must here, how-
ever, state that I am obliged to speak loosely
respecting this matter, as the subject has not
yet been thoroughly investigated. The use of
this tapetum has not been ascertained, or the
reason why it exists in some and is absent in
other animals explained. It is obvious that
where it is present the rays of light are trans-
mitted through the retina, and again when
reflected by the tapetum are returned through
the same retina, thus twice pervading that
structure.

N 2

180

EYE.

'On the outside and anterior part of the
choroid, where the margin of that membrane
corresponds to the place of union between the
sclerotic and cornea, a peculiar and distinct
formation exists apparently for the purpose of
securing a firm union between the two mem-
branes. It is commonly called the ciliary liga-
ment, also orbiculus ciliaris, circulus ciliaris,
by Lieutaud plexus ciliaris, by Zinn annulus
cellulosus, and by Sbmmerring gangliform ring.
It is a gray circle of soft cellular membrane
about two lines broad, applied like a band
round the margin of the aperture into which
the iris is fitted. It adheres closely to the
choroid, and almost equally closely to the scle-
rotic, especially in the groove where the cornea
joins that membrane. It contains few red
vessels, and is not stained by the black pig-
ment; consequently it is of a whitish colour.
The ciliary nerves penetrate it and subdivide
in its structure. Hence it has been considered
by Sommerring as a ganglion, and had been
previously described by Lieutaud as a nervous
plexus. The ciliary nerves, however, merely
pass through, and may easily be traced on to
the iris. It is evidently a mere band of cellular
membrane serving to bind the choroid and
sclerotic together at this point, and is obviously
a provision essentially necessary for the perfec-
tion of the anatomical mechanism of the eye,
as without it the aqueous humour must, from
pressure on the eyeball, be forced back be-
tween the two membranes. In man it is broader
in proportion than in the larger quadrupeds,
and in birds it is particularly large and dense,
adhering more closely to the circle of osseous
plates than to the choroid, and consequently
presents a very remarkable appearance when
the latter membrane is pulled off with the
ciliary processes and iris, an appearance to
which the attention of anatomists was first
drawn by Mr. Crampton. From its position
and appearance the ciliary ligament has often
been suspected to be a muscular organ, destined
by its contraction to alter the form of the cornea,
and thus adapt the eye to distance. There is
not, however, sufficient evidence to sustain
such an opinion. The plate introduced to
represent the ciliary nerves, as well as that
which represents the iris, exhibit this part of
the organization of the eyeball in connexion
with the choroid.

On the inside of the choroid, surrounding
the aperture into which the iris is fitted, and
corresponding in position within to the ciliary
ligament without, exists another peculiar pro-
vision destined to establish a connexion between
this part and the hyaloid membrane of the
vitreous humour, as the ciliary ligament esta-
blishes a similar connexion between the sclerotic
and choroid. This is the corpus ciliare or
ciliary processes, called sometimes incorrectly
ciliary ligament, and by Sommerring corona
ciliaris. It is composed of a number of dis-
tinct folds or productions of the choroid, having
their anterior extremities extended to the back
of the iris, while the posterior gradually dimi-
nish until lost in the membrane from which
they originate. Each fold or ciliary process is

a production or continuation of the choroid,
and cannot be separated from it unless clipped
off by the scissors. They appear to be com-
posed altogether of a remarkable interlacement
of arteries and veins derived from those of the
choroid, and exhibit no appearance whatsoever
of muscular organization, although considered
by Porterfield and others as endowed with that
function. These are sixty or seventy in num-
ber, fifty-seven being enumerated by Sommer-
ring, and seventy by Zinn. They are about
two lines in length, but are not equally so,
every alternate one being shorter than the next
to it. The free internal margin of each ciliary
process is buried in the hyaloid membrane of
the vitreous humour at its anterior part, round
the circumference of the crystalline lens, and a
corresponding production of the hyaloid mem-
brane projects into the space between these
processes so as to establish a most perfect bond
of union between the two structures. The
ciliary processes appear to be attached to the
circumference of the lens, and are often de-
scribed as having such connexion. This, how-
ever, is not the case. The anterior extremities
do not touch the circumference of the lens;
they project into the posterior chamber of the
aqueous humour up to the back of the iris,
and consequently constitute the circumferen-
tial boundary of that cavity. When the eye
becomes flaccid from evaporation after death,
the ciliary processes fall down to the margin of
the lens and appear to adhere ; but if the cornea
and iris be removed from the eye of a subject
recently dead, a circle of hyaloid membrane
may distinctly be seen occupying the space
between the ciliary processes and lens, through
which the observer can see to the bottom of
the eye. This space is represented and pointed
out in Sommerring's plates. The annexed
figure from Zinn's work represents the corpus
ciliare or circle of ciliary processes on a large
scale.

Fig. 105.

The choroid, in common with several other
parts of the eye and its appendages, is stained
by a black colouring matter secreted in and
upon different textures. In man it is of a dark-
brown colour, but in other animals is generally

EYE.

181

black, and so loosely connected with the struc-
ture in which it is deposited, that in dissecting
the eyes of our common graminivorous animals
under water it becomes diffused, and colours the
fluid as the ink of the cuttle-fish obscures the
water into which it is shed. It is not confined
to anyone particular structure, but is deposited
in every situation where it is necessary for the
purpose for which it is destined. It is found
in considerable quantity on the inner surface of
the choroid, where it appears as if laid on in
the form of a paint, and is frequently so
described ; but it is much more probable that
it is deposited in the interstices of the exqui-
sitely fine cellular membrane which connects
the choroid with the delicate covering of the
retina. In this situation it often, especially in
infants, presents the appearance of a perfectly
distinct black membrane, which may be peeled
off in flakes or allowed to remain on the retina
in patches, as noticed by Haller. It also per-
vades the structure of the choroid, at least in
the adult, and even stains the inner surface of
the sclerotic and the cellular layer which con-
nects these two membranes. It is deposited
in larger quantity in the ciliary processes and
upon the back and in the texture of the iris.
In many animals it is found forming a black
ring round the margin of the cornea and in the
edge of the third eye-lid, as well as in the
pecten or marsupium nigrum in birds. It is
even -sometimes found scattered, as if acci-
dentally, as in the texture of the sclerotic in
hogs, and within the sheaths of the optic nerve
in oxen; it is obvious that it does not require
any special form of organization for its produc-
tion, but is merely secreted into the cellular
membrane, where necessary, as the colouring
matter is secreted with cuticle on the skin.

It is darker in the earlier periods of life, and
in the infant is more confined to the inner sur-
face of the choroid and to the posterior surface
of the iris, than pervading the texture of either
of these membranes. In old age it evidently
fades, and even appears as if absorbed in
patches. It is sometimes altogether absent, as
in those animals called albinos, where all the
parts usually coloured are unstained. Its use
is obviously to prevent the rays of light from
being reflected from surfaces where they should
be absorbed, a provision as essential to the
perfection of the animal eye as to the artificial
optical instrument. It is also applied to give
complete opacity to prevent the transmission of
light, and hence is deposited in large quantity
in and on the iris, as well as in the ciliary pro-
cesses which correspond in situation to the
exposed part of the sclerotic, through which
the light might otherwise pass to the bottom of
the eye, and disturb correct vision. The layer
of black pigment on the inner surface of the
choroid has undergone a careful microscopic
investigation, especially by Mr. T. W. Jones,
the results of which are stated in a short
account of the anatomy of the eye prefixed to
the second edition of Mr. M'Kenzie's work on
Diseases of the Eye. He says that it possesses
organization and constitutes a veal membrane,
and when examined with the miscroscope " is

seen to consist of very minute flat bodies of a
hexagonal form, joined together at their edges.
These bodies, which are about -^gth of an inch
in diameter, consist of a central transparent
nucleus, surrounded by an envelope of colour-
ing matter, which is most accumulated at their
edges. The centre, indeed, of each hexa-
gonal plate is a transparent point, and appears
somewhat elevated, the elevations on the inner
surface corresponding to depressions to be
described in the membrane of Jacob. That
part of the membrane of the pigment situated
on the pars non plicata of the ciliary body
around the ciliary processes, and on the poste-
rior surface of the iris, is composed of irregu-
larly rounded bodies, analogous to the hexa-
gonal plates. In albinos the same membrane
exists, but contains no pigment. The bodies
composing it are but little deve-
Fig. 1 06. loped, being nothing but the central
nuclei separated from each other by
large intervals, and not hexagonal,
but circular, or even globular.* The
annexed figure represents this mem-
brane of the pigment as described.
Sometimes the black pigment is totally or
partially deficient, not only in inferior animals,
but also in man, constituting the variety deno-
minated albino, of which the white rabbit
affords a good example. The circumstance has
attracted considerable attention, and has been
the subject of particular observation by Mr.
Hunter, Blumenbach, and many others. Dr.
Sachs has given a curiously elaborate account
of himself and his sister, who are both albinos.
The eye in such cases appears of a beauti-
fully brilliant red, in consequence of the blood
being seen circulating through the transparent
textures unobscured by the pigment, but the
individual suffers from the defect in conse-
quence of the light being transmitted through
all the exposed part of the organ; proving
that the covering of black pigment is deposited
on the back of the iris and in the ciliary pro-
cesses to obviate this injurious consequence.
In human albinos the eyes have often a tremu-
lous oscillating motion, and the individual is
unable to bear strong light.

The colour of the black pigment does not ap-
pear to depend on the presence of carbon or
other dark material, and the minute quantity
of oxide of iron contained in it is obviously
insufficient for the production of so deep a tint.
It is insoluble in water, either hot or cold, or
in dilute sulphuric acid ; but strong nitric or
sulphuric acids decompose it, and are decom-
posed by it. Caustic potash is said to dissolve
it, though with difficulty, but as ammonia is
evolved during the process, and the nature of
the pigment necessarily altered, it cannot be
considered a case of simple solution. By
destructive distillation it affords an empyreu-
matic oil, inflammable gases, and carbonate of
ammonia. It is, therefore, obviously an ani-
mal principle sui generis, its elements being
oxygen, hydrogen, carbon, and nitrogen. One
hundred parts in a dry state leave, when
incinerated, 4.46 of a calx, consisting of chlo-
ride of calcium, carbonate of lime, phosphate

182

EYE.

of lime, and peroxide of iron. For these par-
ticulars I am indebted to Dr. Apjohn.

Of the iris. — This is the circular partition or
screen interposed between the cornea and crys-
talline lens, filling up the aperture in the ante-
rior part of the sphere of the choroid, and conse-
quently exactly fitted to the place of union of the
ciliary ligament and choroid with the sclerotic
round the cornea. It has an aperture in the
centre called the pupil, through which the central
portion of the pencil of rays incident upon the
cornea is transmitted, while the extreme rays
are intercepted; and appears to answer the
same purpose as the diaphragm or eye-stop in
the telescope, but with this advantage, that it
is enlarged or diminished according to the
quantity of light, the distance of objects, or
even the will of the individual. The iris is
frequently called uvea^ a term also applied to
the spherical choroid; or the anterior part is
called iris, and the posterior uvea. To avoid
confusion the term should be discarded alto-
gether, and that of iris alone retained to
designate this important part of the organ.

The surface of the iris is flat or plane, al-
though it appears convex when seen through
the cornea, or when in dissecting the eye it
falls on the convex surface of the crystalline
lens. It is remarkable that the aperture or
pupil is not exactly in the centre of the disc,
but a little towards the inside. The anterior
surface presents a very peculiar and remarkable
appearance, evidently not depending on or
arising from vascular ramifications or nervous
distribution. This appearance is described
with precision and accuracy both by Zinn and
Haller, although unnoticed or only briefly al-
luded to in many of the slovenly compilations
which have appeared since they wrote. It is,
however, described by Meckel, who saw what
he describes, and read what he quotes. Mailer's
words are as follow : — " In anteriori lamina
iridis eminet natura flocculenta, vane in flam-
mulas quasdam introrsum euntes disposita,
quibus aliqua est similitudo rotundorum ar-
cuum, ad centrum pupillse convexorum. Qui-
vis flocculus est serpentinarum striarum intror-
sum convergentium, et intermistarum macu-
larum fuscarum congeries : conjunct! vero
flocculenti fasciculi arcum quasi serratum, emi-
nentem, ad aliquam a pupilla distantiam effi-
ciunt, qui convexus eminet, quasi antrorsum,
supra rehquum planum pupillaeelatus. Fabricae
pulchritudinem nulla icon expressit." (Ele-
menta Physiologise, torn. v. p. 369.) Zinn's
description is equally accurate and precise.
In the 12th volume of the Medico-Chirurgical
Transactions I have noticed this structure in
the following words: " If the iris be attentively
examined in the living subject, or under water
after the cornea has been removed, a number
of irregularly shaped masses may be seen pro-
jecting from the middle space between the
circumference and the pupil. From the con-
vexities of these masses, a number of elevated
lines, equally irregular in size and number,
proceed toward the pupil, and attach them-
selves at the distance of about a twentieth
pail of an inch from its margin, and from this

point of attachment a number of much smaller
stria converge to the edge of the central open-
ing. It is quite impossible for words to give
an adequate idea of this appearance. If I
ventured to compare it with any other with
which I am acquainted, I should say that it
resembled strongly the earner columns and
corda tendinea of the heart, both in form,
arrangement, and irregularity of conformation.
This structure is more strongly marked in the
hazel than in the blue iris ; and in many cases
the fleshy projections coalesce, by which they
appear less distinct ; but the loops or cords
which, arise from them always exist, and often
project so much from the plane of the iris as
to admit of having a small probe or bristle
passed beneath them. That this appearance of
the iris does not depend on any particular
disposition of its vessels, is, I think, obvious,
from the thickness of these cords or striae being
so much greater than the vessels of the iris,
from their being arranged in a manner altogether
different from vascular inosculation, and finally,
because the iris when successfully injected and
expanded does not present that interlacement
of branches surrounding the pupil which has
so often been described from observation of its
uninjected state/' The anterior surface of the
iris is of a light blue colour in persons of fair
skin and light hair, of a blue grey in others,
sometimes of a mixture of tints called a hazel
iris ; and in negroes and others, where the skin
is stained by the usual colouring matter, the
iris is of a deep brown, and is commonly
described as a black eye, being pervaded by
the black pigment throughout its texture, as
well as coated with it on its posterior surface.
In animals altogether destitute of the usual
colouring matter on the surface, called albinos,
the iris has no other colour than that of the
blood which circulates in its vessels. The
annexed engraving is a copy of a most accu-
rately executed representation of the face of
the iris, shewing the earner columns and
cor da tendinea much magnified.

Fig. 107.

The posterior surface of the iris is as remark-
able as the anterior, but altogether different in
its nature. I have given the following des-
cription of it in the paper to which I allude in

EYE.

182

the Medico-Chirurgical Transactions. " In
order to obtain a correct view of the posterior
surface of the iris, a transverse vertical section
of the eye should be made at the distance of
about an eighth of an inch behind the cornea,
and the lens, and portion of vitreous humour
attached to it, removed : the iris now appears
covered by a thick layer of black pigment,
marked by a number of converging lines ;
these lines on close inspection are found to be
channels or hollows, as if resulting from a
puckering or folding of the membrane. The
pigment is secured from being detached, and
diffused in the aqueous humour, by a fine
transparent membrane, which is closely attached
to the margin of the pupil, from whence it is
continued over the back of the iris, and anterior
extremities of the ciliary processes, to the cir-
cumference of the lens, over the front of the
capsule of which it is also probably extended,
if it be, as may be supposed, the membrane of
the aqueous humour. This delicate membrane
may be turned down by the point of a needle ;
as it is connected to the iris by loose cellular
structure only, in the interstices of which the
black pigment is deposited. It is at first black,
but by gentle agitation in water the colouring
matter is removed, and the membrane remains
transparent. When the membrane and pig-
ment have been removed, the back of the iris
appears free from colour, and marked by a
number of delicate elevated folds, converging
from the ciliary processes to within a short
distance of the pupil ; they are permanent and
essential, and seem of the same nature as the
ciliary processes. The pupil is immediately
surrounded by a well-defined distinct circle,
about the twentieth part of an inch in diameter,
of a denser structure than the rest of the iris :
this is what has been long described as the
orbicular muscle, or constrictor of the pupil.
If the iris be treated, as I before mentioned, by
maceration and extension, this appearance still
preserves its integrity, and retains its original
character." Haller and Zinn describe these
converging radiating folds, but the former de-
nies the existence of the circular arrangement
round the margin of the pupil, of the presence
of which I do not entertain the slightest doubt,
but which is sometimes so slightly marked,
that I am not surprized to find its existence
doubted if the part has not been examined in
a variety of examples. This circle, or orbicular
muscle, is sometimes equally visible on the
anterior surface, but is generally obscured by
the converging cords above described. The
folds or elevations on the back of the iris, con-
verging toward the pupil, have been considered
the muscular agents for dilating the pupil, but
if examined in the eyes of the larger quadru-
peds, it is obvious that they are destined to give
this part of the organ the requisite degree of
opacity, and to afford an appropriate place for
the deposit of the black pigment, in this res-
pect closely resembling the ciliary processes,
and the pecten in the eye of birds, so much
so, that I think they might be appropriately
called the ciliary processes of the iris.

The iris is most plentifully supplied with

bloodvessels and nerves. Thi two long .ciliary
arteries which penetrate the sclerotic posteri-
orly advance horizontally, about the middle
of the eyeball, between that membrane and the
choriod, to the iris, where each divides into two
branches, which proceed round the circumfer-
ence and inosculate with each other, thus form-
ing an arterial circle, from which numberless
branches converge to the pupil. Much impor-
tance has been attached by anatomists to the
manner in which these radiating vessels are
disposed, in consequence of the representation
of Ruysch, who exhibited them as forming a
series of inosculations at a short distance from
the pupil, since called the lesser circle of the
iris. I do not deny that the vessels of the iris
inosculate as in other parts of the body, but I
do not believe that they present this very re-
markable appearance, and I suspect that
Ruysch exaggerated what he had seen, or de-
scribed from an iris in which the injection had
been extravasated and entangled in the tendi-
nous cords, which I have described as extend-
ing from the fleshy bodies to the margin of the
pupil. The question is fortunately of no
importance. It is sufficient to know that the
organ is amply supplied with arterial blood.

The iris is plentifully furnished with
nerves : they are derived from the third and
fifth pairs, with communications from the sym-
pathetic, and consequently having connexions
with the sixth. They penetrate the sclerotic
posteriorly, and advance towards the iris be-
tween the sclerotic and choroid, about fifteen
or twenty in number: arrived at the ciliary
ligament, they divide at acute angles, and may
be traced through this structure until they are
finally lost in the iris, as seen in the annexed
figure.

Fig. 108.

From the foregoing description, it appears
that the iris is eminently distinguished for the
perfection of its organization ; and endowed as
it is with the power of enlarging or diminishing
the aperture in its centre, there can be little
doubt that it is a beautiful application of mus-
cular structure and function to the perfection
of this most elaborately constructed organ.
The authority of Haller operates to the pre-
sent day to throw a doubt upon the muscula-
rity of the iris ; but Haller, strange as it may
appear, was not correctly informed in many
particulars respecting this structure. He de-
nies the existence of the orbicular muscle ; he
doubts the irritability of the organ, and he even

184

EYE.

considers it destitute of sensibility, and as-
sumes that the pupil is dilated after death.
Any anatomist may, however, demonstrate the
orbicular muscle; any surgeon breaking up a
cataract, may elicit the irritability, and see the
pupil contract, as the fragments of the lens or
the side of the needle touch its margin. The
pain produced by pinching or cutting the iris
in operations for cataract and artificial pupil is
no longer matter of doubt, and the assumption
that the pupil dilates when death takes place
is disproved by daily observation. The pupil
contracts to exclude light when too abundant,
and dilates to admit it when deficient in quan-
tity ; the heart contracts to expel the blood,
and dilates to receive it; the diaphragm con-
tracts to fill the lungs, and relaxes to assist in
emptying them. I can see no material differ-
ence between the phenomena exhibited by the
actions of the iris, and those displayed by the
muscular system generally. I believe that when
the pupil contracts to intercept light, that con-
traction is accomplished by the orbicular mus-
cle, which operates as any other sphincter;
and that when the pupil is dilated to admit
light, the dilatation is accomplished by the con-
traction of the structure, which I have said re-
sembles the earner columns and corda tendinea
in the heart.

During fetal life the aperture in the centre is
closed by a membrane, hence technically called
membrana pupillaris. The discovery 'of this
membrane was first announced by Wachendorf,
but was subsequently claimed by Albinus, and
still later by Dr. Hunter for a person of the
name of Sandys. It is usually described as
existing from the earliest period of fetal life to
the seventh month, when it disappears. In the
paper communicated by me to the Medico-
Chirurgical Society, I have endeavoured to
shew that this description is not correct, but that
this membrane continues to the ninth month.
The account there given is as follows : " If the
eye be examined about the fifth month, the
membrana pupillaris is found in great perfec-
tion, extended across a very large pupil ; the
vessels presenting that singular looped arrange-
ment, (with a small irregular transparent por-
tion in the centre,) well depicted by Wrisberg,
Blumenbach, Albinus, Sommerring, Cloquet,
and others. About the sixth month it is equally
perfect; the pupil is however smaller, the iris
being more developed. Subsequently to this
date the vessels begin to diminish in size and
number, and a larger transparent portion occu-
pies the centre. At the approach of the eighth
month, a few vessels cross the pupil, or ramify
through the membrane at a short distance from
the margin, without at all presenting the looped
appearance of the previous period, but ad-
mitting a free communication between the ves-
sels of the opposite side of the iris. The pupil
is now still more diminished in size, and the
iris has assumed its characteristic coloured ap-
pearance ; notwithstanding the absence of ves-
sels, the membrane still preserves its integrity,
though perfectly transparent. The period now
approaches when it is^to disappear; this occur-
rence takes place, according to my observations,

a short time previous or subsequent to birth.
In every instance where I have made the exa-
mination, I have found the membrana pupillaris
existing in a greater or less degree of perfection
in the new-born infant; frequently perfect
without the smallest breach, sometimes pre-
senting ragged apertures in seveyal places, and,
in other instances, nothing existing but a rem-
nant hanging across the pupil like a cobweb.
I have even succeeded in injecting a single ves-
sel in the membrana pupillaris of the ninth
month. Where I have examined it in subjects
who have lived for a week or fortnight after
birth, as proved by the umbilicus being healed,
I have uniformly found a few shreds still re-
maining. It is obvious from the preceding
observations, that the membrane does not dis-
appear by a rent taking place in the centre,
and retraction of the vessels to the iris, as sup-
posed by Blumenbach, but that it at first loses
its vascularity, then becomes exceedingly thin
and delicate, and is finally absorbed. The de-
monstration of what I have advanced respect-
ing this delicate part is attended with much
difficulty, and requires great patience. The
display of the membrana pupillaris of the seventh
month is comparatively easy ; but at the ninth
month, or subsequently, it can only be accom-
plished by particular management. The eye,
together with the appendages, should be care-
fully removed from the head ; it should then
be freed from all extraneous parts by the scis-
sors, under water, and a careful section made
at a short distance behind the cornea; taking
care to include the vitreous humour in the divi-
sion, in order that the lens may remain in its
proper situation. The portion to be examined
should now be removed into a shallow vessel of
water, to the bottom of which a piece of wax
has been secured. The operator should be
provided with fine dissecting forceps and nee-
dles in light handles; with one needle he
should pin the sclerotic down to the wax, and
with the other raise the lens, and portion of
vitreous humour attached to it, from the ciliary
processes, and separate the ciliary ligament
from the sclerotic. He may now expect to dis-
cover the membrana pupillaris, but its perfect
transparency renders it completely invisible;
he may, however, ascertain the existence, by
taking a minute particle of the retina and
dropping it into the centre of the pupil, where
it remains suspended if this membrane exist.
The preparation should now be taken up in
a watch-glass, and placed in a weak mix-
ture of spirit and water, and a little pow-
dered alum raised on the point of a needle
dropped upon it. After a day or two it may
be examined; and if the membrane be pre-
sent, it has become sufficiently opaque to
be visible, and may now be suspended in a
bottle of very dilute spirit." In the annexed
engravings, A represents the membrana pu-
pillaris of about the fifth month, present-
ing the peculiar looped arrangement of the
vessels. B represents the membrane about the
eighth month, not presenting the looped ar-
rangement. C represents the membrane with a
red vessel in its structure at the ninth month . D

EYE.

185

shews a few shreds of the membrane remaining
a week or more after birth.

Fig. 109.

Fig. 110.

The pupil is closed by this membrane during
foetal life in order to preserve its dimensions,
and secure a correct growth of the iris while the
organ is in darkness. If the membrane disap-
peared about the seventh month, the pupil
should become dilated and remain so during
the two succeeding months, unless the muscu-
lar power be undeveloped, which is not proba-
ble, as it may be seen to operate shortly after
birth.

Of the retina. — This is the third spheri-
cally disposed membrane entering into the
structure of the eye, and may be considered
the most essential of all, being that which
is endowed with the peculiar description of
sensibility which renders the individual con-
scious of the presence of light. It is as
exactly fitted to the inside of the choroid as
that membrane is to the sclerotic, but does
not extend to the anterior margin of the choroid
as that structure extends to the anterior margin
of the sclerotic. The retina is destined to be
penetrated by the rays of light, which, reflected
from surround ing objects, are collected to form
images on the bottom of the eye, consequently
its extension as far forward as the choroid or
sclerotic is unnecessary, and nature makes no-
thing superfluous. It is discontinued at the
posterior extremities of the ciliary processes of
the choroid, at the distance of about an eighth
of an inch from the anterior margin of that
membrane.

The retina is evidently the optic nerve ex-
panded in the bottom of the eye in the form of
a segment of a sphere. That nerve differs, in
some respects, in construction from the other
nerves of the body. In its course from the
hole in the bone through which it enters the
orbit until it enters the eye, it is of a cylindrical
form, and proceeds in a waving line to its desti-
nation. The medullary fibres are involved in a
tough strong material, not separable into cords
or bundles as in other nerves, but constituting
a cylinder of collected tubes, from the divided
extremity of which the medullary matter may be
squeezed in as soft and pulpy a form as it exists

in the brain. It is not easy to determine by
anatomical investigation, whether the medullary
material is disposed in tubes or in a cellular
structure, but as that material is universally
disposed in a fibrous form, both in brain and
nerve, it is more than probable that it is so ar-
ranged here. These cerebral fibres involved
thus in a cylindrical bundle of tubes, techni-
cally called neurilema by modern anatomists,
is covered externally by a fine transparent
membrane, adhering to it so closely that it re-
quires some care to separate it; and this is
again covered by a tube of strong fibrous mem-
brane, the sheath of the optic nerve continued
from the dura mater to the sclerotic, to which
membrane it adheres so firmly, that it cannot
be separated except by the knife. Formerly
the sclerotic was considered to be a continuation
of the dura mater, and much importance, in a
pathological point of view, was attached to the
circumstance, but although both structures are
of the fibrous class, the sclerotic is very different
in texture, and the adhesion between them is
not more remarkable than any other of the
numerous adhesions which occur between fi-
brous membranes.

Where the optic nerve enters the eye, it is
contracted in diameter, as if a string had been
tied round it, and then passes through a hole
in the sclerotic, to which it adheres. When
seen from the inside, after removing the retina
and choroid, it appears in the form of a circu-
lar spot, perforated with small holes, from
which the medullary material may be expressed.
This is the lamina cribrosa of Albinus, consi-
dered to be a part of the sclerotic, but which is
really nothing more than the terminating ex-
tremity of the nerve.

The optic nerve does not enter the eye in the
centre of the globe, but about an eighth of an
inch to the side of it, assuming the centre to
correspond to the extremity of a line passing
from the middle of the cornea, through the
centre of the eyeball to its back. The nerve
is generally described and represented as pro-
jecting in the form of a round prominence, as
it enters the eye ; but this is not, I believe, the
state of the part during life, but is produced
by the contraction of the neurilema pressing
out the medullary matter in this form. As
the nerve enters the eye, it immediately expands
into and constitutes the retina, the medullary
fibres separating and spreading out on the sphe-
rical vitreous humour. The expansion of the
nerve in separate fibres cannot be distinctly
seen in the human eye, but may be recognized
with some care in the eye of the ox, and with-
out difficulty in that of the hare and rabbit,
where it divides into two bundles, as has been
well described by Zinn in the Gottingen Com-
mentaries.

The retina does not consist of medullary or
cerebral fibrous matter alone. As the brain
has its pia mater and arachnoid membrane,
and the nerve its neurilema, this nervous struc-
ture has its appropriate provision for its sup-
port and the distribution of its vessels. This
is the vascular layer, first accurately described
by Albinus. It is a delicate transparent mem-

186

EYE.

brane, of such strength, that when detached, it
may be moved about in water, and freely ex-
amined without breaking. It adheres so firmly
to the hyaloid membrane of the vitreous hu-
mour in the fresh eye, that it cannot be sepa-
rated entire, and the medullary fibres adhere
so closely to its external surface, that they can-
not be detached at all in the form of a distinct
membrane. To demonstrate the vascular layer,
the sclerotic should be carefully removed, leav-
ing a portion of the optic nerve freed from its
sheath ; the choroid should then also be re-
moved under water, by tearing it asunder with
a pair of forceps in each hand. The vitreous
humour, covered by the retina only, should
then be allowed to remain about two days in
the water, at the end of which time the me-
dullary layer softens and separates into flakes,
which may be scraped from the vascular layer
beneath by passing the edge of a knife gently
over it, after which the vascular layer may be
detached by careful management, and sus-
pended in a bottle from the optic nerve.

The retina is supplied with blood from the
ophthalmic artery, a small branch of which
penetrates the optic nerve at a short distance
from the back of the eye, and proceeds through
its centre until it arrives at the retina. The
hole in the centre of the nerve, through which
it passes, was formerly called the porus options.
Arrived at the retina, the vessel, under the
name of the central artery of the retina, divides
into two branches, which surround the foramen
of Sommerring, and sending ramifications in
every direction, terminate by encircling the an-
terior margin. Besides the branches which
carry red blood, the central artery probably
furnishes a transparent branch to the centre of
the vitreous humour, as such a branch running
on to the back of the crystalline lens, may be
injected in the eye of the foetus, and a transpa-
rent production from the central artery into the
vitreous humour may be observed in the eyes
of oxen and other large animals. The arteries
of the retina supply the vitreousj humour with
blood, as no other source exists, except from
the ciliary processes of the choroid, which,
being buried in the hyaloid membrane, most
probably furnish vessels to the anterior part,
and in dissecting the vascular layer above de-
scribed, in which the vessels ramify, it is found
to adhere to the hyaloid membrane by points
along the course of the vessels, which points, it
is reasonable to believe, are small branches.

As the medullary or cerebral fibres of the
retina are sustained on the inside by the vascu-
lar layer above described, they are also protected
on the outside by another membrane, which
separates them from the inner surface of the
choroid. This is the membrane which I des-
cribed in a communication in the Philosophical
Transactions in 1819, and as I cannot give a
more intelligible account of it than that there
contained, 1 venture to introduce it here.

" Anatomists describe the retina as consisting
of two portions, the medullary expansion of
the nerve, and a membranous or vascular layer.
The former externally, next to the choroid coat,
and the latter internally, next to the vitreous

humour. All, however, except Albinus and
some of his disciples, agree, that the nervous
layer cannot be separated so as to present the
appearance of a distinct membrane, though it
may be scraped off, leaving the vascular layer
perfect. That the medullary expansion of the
optic nerve is supported by a vascular layer,
does not, I think, admit of doubt ; but it does
not appear that Albinus was right in supposing
that the nervous layer can be separated in form
of a distinct membrane, though shreds of a
considerable size may be detached, especially if
hardened by acid or spirit.

" Exclusive of these two layers, I find that
the retina is covered on its external surface by
a delicate transparent membrane, united to it
by cellular substance and vessels. This struc-
ture, not hitherto noticed by anatomists, I first
observed in the spring of the last year, and
have since so frequently demonstrated, as to
leave no doubt on my mind of its existence as
a distinct and perfect membrane, apparently of
the same nature as that which lines serous cavi-
ties. I cannot describe it better, than by detailing
the method to be adopted for examining and dis-
playing it. Having procured a human eye,
within forty-eight hours after death, a thread
should be passed through the layers of the cor-
nea, by which the eye may be secured under
water, by attaching it to a piece of wax, previ-
ously fastened to the bottom of the vessel, the
posterior half of the sclerotic having been first
removed. With a pair of dissecting forceps
in each hand, the choroid coat should be gently
torn open and turned down. If the exposed
surface be now carefully examined, an ex-
perienced eye may perceive, that this is not
the appearance usually presented by the retina ;
instead of the blue-white reticulated surface of
that membrane, a uniform villous structure,
more or less tinged by the black pigment, pre-
sents itself. If the extremity of the ivory
handle of a dissecting knife be pushed against
this surface, a breach is made in it, and a mem-
brane of great delicacy may be separated and
turned down in folds over the choroid coat,
presenting the most beautiful specimen of a
delicate tissue which the human body affords.
If a small opening be made in the membrane,
and the blunt end of a probe introduced be-
neath, it may be separated throughout, without
being turned down, remaining loose over the
retina ; in which state if a small particle of paper
or globule of air be introduced under it, it is
raised so as to be seen against the light, and is
thus displayed to great advantage ; or it is
sometimes so strong as to support small glo-
bules of quicksilver dropped between it and
the retina, which renders its membranous na-
ture still more evident. If a few drops of acid
be added to the water after the membrane has
been separated, it becomes opaque and much
firmer, and may thus be preserved for several
days, even without being immersed in spirit.

" That it is not the nervous layer which I de-
tach, is proved by the most superficial exa-
mination ; first, because it is impossible to
separate that part of the retina, so as to present
the appearance I mention ; and, secondly, be-

EYE.

187

cause I leave the retina uninjured, and present-
ing the appearance described by anatomists,
especially the yellow spot of Soemmerring,
which is never seen to advantage until this
membrane be removed : and hence it is that
conformation, as well as the fibrous structure
of the retina in some animals, become better
marked from remaining some time in water,
by which the membrane I speak of is de-
tached.

" The extent and connections of this mem-
brane are sufficiently explained by saying, that
it covers the retina from the optic nerve to the
ciliary processes. To enter into farther inves-
tigation on this subject would lead to a dis-
cussion respecting the structure of the optic
nerve, and the termination of the retina an-
teriorly, to which it is my intention to return at
a future period.

"The appearance of this part I find to vary
in the different classes of animals and in man,
according to age and other circumstances. In
the fetus of nine months it is exceedingly de-
licate, and with difficulty displayed. In youth
it is transparent, and scarcely tinged by the
black pigment. In the adult it is firmer, and
more deeply stained by the pigment, which
sometimes adheres to it so closely as to colour
it almost as deeply as the choroid coat itself;
and to those who have seen it in this state, it
mustappear extraordinary that it should not have
been before observed. In one subject, aged
fifty, it possessed so great a degree of strength
as to allow me to pass a probe under it, and
thus convey the vitreous humour covered by it
and the retina from one side of the basin to the
other ; and in a younger subject I have seen it
partially separated from the retina by an effused
fluid. In the sheep, ox, horse, or any other
individual of the class mammalia which I have
had an opportunity of examining, it presents
the same character as in man ; but is not so
much tinged by the black pigment, adheres
more firmly to the retina, is more uniform in its
structure, and presents a more elegant appear-
ance when turned down over the black choroid
coat. In the bird it presents a rich yellow brown
tint, and when raised, the blue retina presents it-
self beneath; in animals of this class, however, it
is difficult to separate it to any extent, though I
can detach it in small portions. In fishes, the struc-
ture of this membrane is peculiar and curious.
It has been already described as the medullary
layer of the retina by Haller and Cuvier, but
I think incorrectly, as it does not present any
of the characters of nervous structure, and the
retina is found perfect beneath it. 1 f the scle-
rotic coat be removed behind, with the choroid
coat and gland so called, the black pigment is
found resting upon, and attached to, a soft
friable thick fleecy structure, which can only
be detached in small portions, as it breaks
when turned down in large quantity. Or if the
cornea and iris be removed anteriorly, and the
vitreous humour and lens withdrawn, the retina
may be pulled from the membrane, which re-
mains attached to the choroid coat, its inner
surface not tinged by the black pigment, but

presenting a clear white, not unaptly compared
by Haller to snow.

" Besides being connected to the retina, I find
that the membrane is also attached to the cho-
roid coat, apparently by fine cellular substance
and vessels ; but its connection with the retina
being stronger, it generally remains attached
to that membrane, though small portions are
sometimes pulled off with the choroid coat.
From this fact I think it follows, that the
accounts hitherto given of the anatomy of these
parts are incorrect. The best anatomists de-
scribe the external surface of the retina as
being merely in contact with the choroid coat,
as the internal with the vitreous humour, but
both totally unconnected by cellular mem-
brane, or vessels, and even having a fluid
secreted between them : some indeed speak
loosely and generally of vessels passing from
the choroid to the retina, but obviously not
from actual observation, as I believe no one
has ever seen vessels passing from the one
membrane to the other. My observations lead
me to conclude, that wherever the different
parts of the eye are in contact, they are con-
nected to each other by cellular substance,
and, consequently, by vessels ; for I consider
the failure of injections no proof of the want
of vascularity in transparent and delicate parts,
though some anatomists lay it down as a cri-
terion. Undoubtedly the connection between
these parts is exceedingly delicate, and, hence,
is destroyed by the common method of ex-
amining this organ ; but I think it is proved
in the following way. I have before me the
eye of a sheep killed this day, the cornea
secured to a piece of wax fastened under water,
and the posterior half of the sclerotic coat
carefully removed. I thrust the point of the
blade of a pair of sharp scissors through the
choroid coat into the vitreous humour, to the
depth of about an eighth of an inch, and
divide all, so as to insulate a square portion
of each membrane, leaving the edges free, and
consequently no connection except by surface ;
yet the choroid does not recede from the mem-
brane I describe, the membrane from the
retina, nor the retina from the vitreous humour.
I take the end of the portion of choroid in the
forceps, turn it half down, and pass a pin
through the edge, the weight of which is in-
sufficient to pull it from its connection. I se-
parate the membrane in like manner, but the
retina I can scarcely detach from the vitreous
humour, so strong is the connection. The
same fact may be ascertained by making a
transverse vertical section of the eye, removing
the vitreous humour from the posterior seg-
ment, and taking the retina in the forceps,
pulling it gently from the choroid, when it will
appear beyond a doubt that there is a connec-
tion between them.

" Let us contrast this account of the matter
with the common one. The retina, a mem-
brane of such delicacy, is described as being
extended between the vitreous humour and
choroid, from the optic nerve to the ciliary
processes, being merely laid between them,

188

EYE.

without any connection, and the medullary
fibres in contact with a coloured mucus re-
tained in its situation by its consistence alone.
This account is totally at variance with the
general laws of the animal economy ; in no
instance have we parts, so dissimilar in nature,
in actual contact: wherever contact without
connection exists, each surface is covered by a
membrane, from which a fluid is secreted ;
and wherever parts are united, it is by the
medium of cellular membrane, of which se-
rous membrane may be considered as a mo-
dification. If the retina be merely in contact
with the vitreous humour and choroid, we
argue from analogy, that a cavity lined by
serous membrane exists both on its internal
and external surface : but this is not the fact.
In the eye a distinction of parts was necessary,
but to accomplish this a serous membrane was
not required ; it is only demanded where great
precision in the motion of parts was indis-
pensable, as in the head, thorax, and abdo-
men; a single membrane, with the interpo-
sition of cellular substance, answers the pur-
pose here. By this explanation we surmount
another difficulty, the unphilosophical idea
of the colouring matter being laid on the
choroid, and retained in its situation by its
viscidity, is discarded ; as it follows, if this
account be correct, that it is secreted into the
interstices of fine cellular membrane here,
as it is upon the ciliary processes, back of the
iris, and pecten, under the conjunctiva, round
the cornea, and in the edge of the membrana
nictitans and sheath of the optic nerve in many
animals. Dissections are recorded where
fluids have been found collected between the
choroid and retina, by which the structure of
the latter membrane was destroyed ; the ex-
planation here given is as sufficient to account
for the existence of this fluid, as that which
attributes it to the increased secretion of a
serous membrane."

The membrane is represented as it exists in
the eye of the sheep, in the annexed figure,
from my paper in the Medico-Chirurgical
Transactions.

Mr. Dalrymple, in his valuable work on the
anatomy of the eye, takes a different view of
the arrangement of this part of the retina:

he says : — " From observations made on the
human eye, in connection with other expe-
riments on the eyes of animal, I am induced
to consider it as a double reflected serous mem-
brane. I was first led to take up this opinion
in the year 1827, by the accidental observation
of a very delicate membrane, which lined and
was adherent to the entire choroid. Having
minutely injected the eye of a sheep, I made
a vertical transverse section through the sclero-
tic, choroid, and retina, which last membrane,
with Jacob's tunic, properly so called, and the
vitreous body I removed. I then placed the
remaining portion of the eye in dilute spirits
of wine, intending to preserve it for the ex-
hibition of the tapetum, which in this instance
was remarkably beautiful. A few minutes
after its immersion the tapetum lost to a con-
siderable extent its brilliant hue, and I re-
moved it from the glass to wash from its sur-
face some deposit, which I thought might
have obscured its polish. In doing this, how-
ever, I detached a delicate membrane, mi-
nutely filled with injection, and this membrane
it was which on being placed in the spirit,
became slightly opaque and produced the effect
alluded to ; for the tapetum thus denuded in-
stantly recovered, and still retains its bril-
liancy."

The inference that the membrane in ques-
tion is a double reflected serous membrane is
certainly more in conformity with analogy than
the assumption that it is a single layer, but this
uniformity in nature's operations has been too
much insisted upon. I have above stated my
reasons for considering it a single layer, and
not a double serous membrane ; and I should be
inclined to think that the layer which Mr. Dal-
rymple found adhering to the choroid was the
membrane itself, which had not come away
with the retina and vitreous humour, as I have
found sometimes to happen, did not Mr. Dal-
rymple further state that he has " in his pos-
session a preparation, which does most dis-
tinctly shew the double portions of this mem-
brane ; one lining the choroid, the other
reflected over the pulpy structure of the retina."
Mr. Jones, in the work formerly alluded to,
gives the annexed representation of the mem-
brane as it appears when Fi<>.ll2
highly magnified. Fig. 113
is a representation of the
membrane by Mr. Bauer,
magnified fifty diameters, from
the Philosophical Transactions
for 1822.

In the centre of the retina, and consequently
in the axis of vision, about an eighth of an
inch from the entrance of the optic nerve, a
very remarkable condition of structure exists.
This is a small point destitute of cerebral or
medullary fibres, appearing like a hole in the
membrane, and hence called the foramen of
Sommerring, from the distinguished anatomist
who discovered it. This point is surrounded
by a yellow margin, and the retina is here also
puckered into a peculiar form of fold. Som-
merring, in the Commentationes Societatis

Fig.113.

Regiae Gottingenses, gives the following
account of the discovery. " On the 27th of
January, 1791, while I examined the eyes of a
very fine and healthy young man, a few hours
previously drowned in the Rhine, being per-
fectly fresh, transparent, and full, and sup-
ported in an appropriate fluid, with the in-
tention of exhibiting a perfect specimen of the
retina to my pupils in the anatomical theatre,
I so clearly detected in the posterior part of
the retina, which was expanded without a
single fold, on account of the perfect state
of the eye, a round yellow spot, that I
was convinced it was a natural appearance,
and not a colour produced by any method of
preparation. In examining this spot more
accurately, I perceived in its centre a little
hole occupying the situation of the true centre
of the retina. With the same care I examined
the other eye and found it exactly similar.
I then communicated the discovery to my
pupils in the public demonstrations." " In this
precise spot, or in the very centre of the re-
tina, is found an actual deficiency of the me-
dullary layer, or a real hole perfectly round,
with a defined margin a fourth of a line in
diameter." " The transparent vitreous humour
and black pigment are so clearly seen through

EYE. 189

this hole, that there can be no doubt that
it is a real aperture, which being situated
in the centre of the retina may be appro-
priately termed the foramen centrule. Sur-
rounding this foramen centrale the remark-
able yellow colour resembling that of gum
guttae is so disposed that it appears much
deeper toward the margin, and totally dis-
appears at a distance of a line. This
colour varies much according to the age of
the individual, being very faint in infants,
much deeper at puberty, on account of the
thickness and whiteness of the retina at
that period, appearing of a deep yellow
brownish or crocus colour. In more ad>-
vanced age the colour is less intense, prin-
cipally on account of the diminished
whiteness of the retina, which also appears
extenuated at that period. Even the
W choroid, where it corresponds to this fora-
men, sometimes appears a little deeper-
coloured."

In the paper above alluded to, published
in the Medico-Chirurgical Transactions, I
. have given the result of some careful in-
quiries into the structure of this part, from
which the following observations are ex-
tracted. " Sommerring describes it as a
hole in the retina with a yellow margin,
mentioning as accidental a fold which
occupies the situation of this hole and
tends to conceal it, and thus accounting
for its remaining so long unnoticed. This
appearance is so constant and remarkable,,
that its existence may be very rationally
considered essential to correct vision, and
it therefore becomes an interesting object
of speculation. The circumstances which
it seems important to ascertain, are, whe-
ther it is actually a hole in the retina with
a yellow margin; whether, in addition
to this hole, the retina is folded or puckered in at
this part ; or whether the appearance of a hole
arises from a deficiency of the medullary layer of
the retina without any orifice in its vascular layer.
Both Sommerring himself and many others seem
to consider that the fold is accidental and the
consequences of changes occurring after death.
It is here necessary to call to mind what those
changes are with respect to the retina. If the
eye had become flaccid previous to dissection,
the retina on being exposed presents an irre-
gular surface, arising from a number of folds
diverging from the optic nerve as from a centre,,
and evidently produced by the loss of support
from the partial evaporation of the fluid of the
vitreous humour. These folds, however, never
observe any regular form, or preserve precise
situations, and may be obliterated by changing
the position of the eye in the water. They
disappear altogether after the part has remained
some time in water, in consequence of the
vitreous humour becoming again distended
from imbibing the fluid in which it is im-
mersed. It however requires no very great
care or experience to distinguish between those
accidental folds and the peculiar one in ques-
tion. If the examination be made from with-
out, removing the sclerotic and choroid behind,

.190

EYE.

the retina appears to be forced or drawn at this
point into the vitreous humour to the depth
of about a twelfth of an inch, the entire fold
being something more than an eighth in length.
At first there is little or no appearance of a
hole, but after the eye has remained for some
time in the water, the fold begins to give way,
and a small slit makes its appearance, which
gradually widens, and assumes the appearance
of a round hole. This hole is large in pro-
portion to the degree to which the fold has
yielded ; and when the fold totally disappears,
as it sometimes does, the transparent point
gives the appearance which Sommerring re-
presents, of a hole with a yellow margin. If,
instead of making the examination in this way
from the outside, we view this part through
the vitreous humour, the appearance of the
hole is more remarkable ; but still that part of
the retina is evidently projected forward be-
yond the level of the rest of that membrane.
In the eye of a young man, which I had an
opportunity of examining under peculiarly
favourable circumstances, within five hours
after death, I noticed the following appear-
ances. The cornea and iris having been cut
away, and the lens removed from its situation,
I placed the part in water, beneath one of the
globular glasses, and held it so as to allow the
strong light of a mid-day sun to fall directly
upon it ; when the retina to the outside of the
optic nerve presented unequivocally the ap-
pearance of being drawn or folded into the
form of a cross or star, with a dark speck in
the centre, surrounded by a pale yellow areola.
I further satisfied myself of the prominence
of the fold by holding a needle opposite to it,
while the light shone full upon it, a shadow
being thus cast upon the retina which deviated
from the straight line when passed over the
situation of the fold. To ascertain whether
there is actually a hole in the retina, or merely
a deficiency of nervous matter at this point,
I allowed the eye to remain for some days in
water, until the connexions of the parts began
to give way. I then introduced a small probe
between the retina and vitreous humour, the
part still remaining in water, and bringing the
blunt point of the instrument opposite the
transparent spot, attempted to pass it through,
but found I could not do so without force
sufficient to tear the membrane. I also re-
moved the nervous matter by maceration and
agitation in water, and on floating the vascular
layer, found that I could no longer ascertain
where the spot had originally existed, there
being no hole in the situation previously occu-
pied by the transparent speck."

It is remarkable that the foramen of Sommer-
ring has not been found in the eyes of any of
the mammalia except those of the quadrumana,
in some of whom it has been detected by Home,
Cuvier, and others, but the extent to which it
may be traced in this tribe has not been satis-
factorily ascertained. Dr. Knox, in a paper in
the Memoirs of the Wernerian Natural History
Society, announces the discovery of its existence
in certain lizards. In the lacerta superc'diosa he
says, " the retina is very thick, and somewhat

firm and opaque. Where the optic nerve enters
the interior of the eye-ball, there is a distinct
marsupiuw or black circular body, proceeding
forwards apparently through the centre of the
vitreous humour. Anteriorly, somewhat supe-
riorly and towards the mesial line or plane, we
perceive, on looking over the surface of the
retina which regards the vitreous humour, a
comparatively large transparent, nearly circular
spot, through which may be distinguished the
dark-coloured choroid. Close to this is gene-
rally placed a fold or reduplication of the retina,
which is in general remarkably distinct. This
fold or folds, (for there are more than one)
either proceed from the transparent point
towards the insertion of the optic nerve, or
close to it. Sometimes the fold seems, as it
were, to lie over the transparent point, and
partly to conceal it from view ; or the point is
formed in the edge of the fold itself, as in apes,
but in general the fold runs directly from
the insertion of the optic nerve upwards and
inwards, pressing very close to the edge of the
foramen centrale." The foramen was also
seen in the lacerta striata, lacerta calotes, and
others, while it was not to be detected in the
gecko, crocodile, and some others. It was also
subsequently discovered in the chameleon.
The annexed figures represent the foramen of
Sommerring in the human eye. A, shews the
retina expanded over the vitreous humour : on
the right is the place from which the optic
nerve was cut away, and from which the ves-
sels branch out : on the left is the foramen of
Sommerring, represented by a black dot sur-
rounded by a dark shade. B, shews the retina
with a portion of the optic nerve. The exter-
nal membrane is turned down as in the pre-
ceding representation of the same structure in
the sheep's eye, and the foramen of Sommer-
ring, instead of a distinct hole, presents the
appearance of a fold or depression with elevated
sides. The wood-engraving does not admit of
the delicacy of finish necessary to express per-
fectly this condition of the part.

Fig. 114.

A.

There is no part of the anatomy of the eye
respecting which there has been so much diver-
sity of opinion as the anterior termination of
the retina. It has already been stated that it
extends to the posterior extremities of the
ciliary processes, where it is discontinued, pre-
senting an undulating edge corresponding to
the indented margin of this part of the corpus
ciliare. Some assert that it extends to the mar-
gin of the lens, others that it is the vascular

EYE.

191

layer only which extends so far, and others that
the vascular layer extends over the lens. No
one however at present, who describes from
observation, denies the termination of the ner-
vous layer at the posterior margin of the ciliary
body, although many insist upon the extension
of the vascular layer to the circumference of the
lens. The subject has received more attention
than it deserves, as it involves no consideration
of importance, either physiological or anato-
mical ; but I am convinced from a very care-
ful scrutiny that no such layer extends between
the ciliary processes of the choroid and those of
the hyaloid membrane ; these two parts being
mutually inserted into each other, as will pre-
sently be explained. In the paper above
quoted in the Medico-Chirurgical Transactions
I have explained what appears to me to be the
arrangement of this part in the following words :
" On removing the choroid, ciliary processes,
and iris, we see the retina terminating with a
denned dentated margin, about a quarter of an
inch from the circumference of the lens : be-
tween this line of termination and the lens, the
vitreous humour retains upon its surface part
of the black pigment which covered the .ciliary
processes. If the eye be examined shortly
after death, removing the black pigment from
this part of the vitreous humour with a camel-
hair pencil, there is an appearance of, at least,
the vascular layer being continued to the lens ;
this part not being so transparent as the rest of
the hyaloid membrane, or so opaque as the retina.
From such an examination I was led to con-
clude that the vascular layer was continued to
the margin of the lens, this part not being
so transparent as the rest of the hyaloid
membrane, or so opaque as the retina. From
such an examination I was led to conclude
that the vascular layer was continued to the
margin of the lens, but I adopted a con-
trary opinion after I had witnessed the change
which took place when the part had remained
twenty-four hours in water : the retina then
separating with a slight force, and frequently
detached by the disturbance given in making
the examination. If, after removing the choroid
without disturbing the retina, the part be al-
lowed to remain in water for some days, the
medullary part of the retina begins to give
way, and may be altogether detached by agita-
tion in water, leaving the vascular layer firmly
attached at the line of termination just de-
scribed. With all the care I could bestow, I
have, however, never succeeded in separating
this layer from the vitreous humour further. If
the maceration be continued for a few days
longer, the vascular layer of the retina gives
way, the larger vessels alone remaining attached
at the original line of termination of the retina,
and appearing to enter the hyaloid membrane
at this part ; the appearance which at first so
much resembled the vascular layer proceeding
towards the lens remaining unchanged, being
in fact part of the vitreous humour itself. The
circumstance which has most strengthened the
notion of the retina being continued forward to
the lens is, that often on raising the choroid and
ciliary processes from the vitreous humour, we

find those processes covered in several places
by a fine semi-transparent membrane insinuated
between the folds ; this is supposed to be the
vascular layer of the retina, but is really the
corresponding part of the hyaloid membrane
which is torn up, being firmly united to this
part of the choroid."

After this article had been prepared for
press, I received an admirable monograph upon
the retina by B. C. R. Langenbeck, son of the
celebrated professor of that name in the Uni-
versity of Gbttingen, in which the nature,
structure, and relations of this most important
and interesting part of the organ are subjected
to a critical and elaborate inquiry. He advo-
cates the membranous nature of the black pig-
ment on the inner surface of the choroid, and
gives an engraving of its organization as ascer-
tained by the microscope, resembling that given
from the essay of Mr. Jones in the preceding
pages. He devotes several pages to the de-
scription of the membrane which I found
covering the medullary layer of the retina, and
adds the testimony of a skilful anatomist in
support of my description, sufficient to coun-
terbalance the convenient scepticism of certain
writers better skilled in making plausible books
than difficult dissections. The fibrous struc-
ture of the medullary layer of the retina is
established, and a plate given of the peculiar
nodulated condition of these fibres. The work
concludes with an account of the morbid
changes of structure observed in the retina, a
subject which, notwithstanding its manfest
importance, has not hitherto attracted the atten-
tion which it deserves. I am indebted to Dr.
Graves for the following abstract of some
recent investigations of Treviranus on the same
subject. " From microscopical examinations
Treviranus demonstrates that the cerebral mass,
both medullary and cortical, consists of hollow
cylinders containing a soft matter. These
cylinders, extremely minute in the cortical
substance, are somewhat larger in the medul-
lary, and still larger in the nerves. In the
retina he finds, that after the optic nerve has
penetrated the sclerotic and choroid, its cylin-
ders or nervous tubes spread themselves out
on every side either singly or collected into
bundles, each cylinder or collection of tubes
bending inwards through the vascular layer,
and terminating in the form of a papilla on
the vitreous humour."

Of the vitreous humour. — It has already
been stated that the globe of the eye is
divided into two chambers by the iris, the
posterior of which is distended by a spherical
transparent mass called the vitreous humour,
which does not completely fill this chamber
between the back of the iris and the hollow
sphere of the retina, but is discontinued or
compressed at a short distance from the back
of the iris, having a narrow space between
it and that membrane, called the posterior
chamber of the aqueous humour. This trans-
parent mass is composed of water containing
certain saline and animal ingredients, deposited
in exquisitely delicate and perfectly transparent
cellular membrane ; hence it is capable of sus-

192

EYE.

taining its own weight and preserving its form
when placed in water, and in air presents the
appearance of a gelatinous mass, scarcely de-
serving the name of solid. The cellular struc-
ture, in which the watery fluid is lodged, has
been called the hyaloid membrane, and the
whole mass denominated the vitreous humour.
The fluid of the vitreous humour, according
to Berzelius, is composed of water, containing
about one and a half per cent, of animal and
saline ingredients; it has a saline taste, and
acquires a slight opaline tint by being boiled. It
consists of water 98.40, chloruret of soda with
a little extractive matter 1.42, a substance solu-
ble in water 0.02, and albumen 0.16. Its
specific gravity is 1.059. When the hyaloid
membrane is examined in its natural state, its
cellular organization can scarcely be ascertained
on account of its transparency ; but if it be
suspended on the point of a pin until the fluid
is allowed to drop out, it may be inflated with
a fine blowpipe and dried, or if the whole be
placed in strong spirit or weak acid, the mem-
brane becomes opaque, and its organization
obvious. It has been supposed that the cells
in which the fluid is lodged present a determi-
nate form, and attempts have been made to
prove this by freezing the eye and examining
the frozen fragments; but any one who has
seen the hyaloid membrane rendered opaque
by acid must allow that the cells are too minute
to admit of such investigation, and that the
frozen masses, supposed to be the contents of
cells, are merely fragments of the hyaloid
membrane with their contained fluid. Although
the hyaloid membrane is perfectly transparent,
and the red particles of the blood do not circu-
late in its vessels, there can be little doubt
that its growth and nutrition are effected by
the circulation of a transparent fluid in vessels
continuous with those conveying red blood.
It is an established fact that transparent tex-
tures which in a natural state do not exhibit
a trace of coloured fluid, when excited or
inflamed, become filled with red vessels, as
may be seen in the conjunctiva. It is there-
fore reasonable to admit that the hyaloid mem-
brane does not present a deviation from this
general law. The fluid of the vitreous humour,
it is to be presumed from analogy, is secreted
by the vessels of the hyaloid membrane, and
if no red vessels can be detected, the secretion
must be accomplished by transparent ones. It
has already been stated that the vascular layer
of the retina adheres to the surface of the
vitreous humour, and that the points of adhe-
sion are stronger along the course of the vessels
than in the intermediate spaces ; it is therefore
most probable that the more superficial part of
the sphere is supplied with transparent blood
from the arteries of the retina, while a branch
directly from the central artery, as it penetrates
the porus opticus, enters behind, and extends
to the back of the lens : such a branch can be
injected in the fetus, and is found to ramify
on the back of the capsule of the lens ; and in
the eyes of large quadrupeds a transparent
production, probably vascular, has been ob-
served proceeding from the entrance of the

optic nerve into the mass of the vitreous
humour. It is also probable that the ciliary
processes of the choroid, which are buried in
the hyaloid membrane anteriorly, supply blood
to that part of the sphere. That the vitreous
humour undergoes changes analogous to those
which take place in textures supplied with red
blood, is proved by its hyaloid membrane
being found opaque and thickened in eyes
which have been destroyed by internal inflam-
mation. A total disorganization of the vitreous
humour is a frequent occurrence, the hyaloid
membrane losing its cohesion to such a degree
that the fluid escapes from the eye as freely as
the aqueous humour when the cornea is divided
in the operation of extraction ; and after the
lens and its capsule have been removed by
operations with the needle, opacity of the
hyaloid membrane is occasionally, although
rarely, observed. Allusion has frequently been
made in books to an appearance in the
eye denominated glaucoma, attributed, rather
vaguely, to opacity of the vitreous humour ; it
appears, however, to be nothing more than the
usual opacity of the lens which occurs in
advanced life, seen through a dilated pupil.
As an additional proof of the vascularity of
the vitreous humour may be adduced the fact,
that in the eyes of sheep, injured by blows in
driving to the shambles, the vitreous humour
is deeply tinged with red blood.

The spherical mass of vitreous humour, it
has already been stated, is exactly fitted into
and adheres to the inner surface of the retina.
From the anterior termination of the retina to
the posterior chamber of the aqueous humour,
it is in contact with, and adhering to, the
ciliary processes of the choroid. Where it is
truncated or compressed on its anterior part to
form the posterior chamber of the aqueous
humour, it has the crystalline lens fitted into a
depression in its centre, while a narrow circle
of it appears between the circumference of the
lens and the anterior extremities of the ciliary
processes of the choroid, forming part of the
boundaries of this chamber of aqueous humour.

If the eye be allowed to remain for a day or
two in water in order to destroy by maceration
the delicate connexions between the hyaloid
membrane and the choroid, and then the
vitreous humour with the lens attached care-
fully separated, the point of a fine blowpipe
may be introduced under the surface of the
hyaloid membrane at the circumference of the
lens, and a series of cells encircling the lens
inflated. This is the canal of Petit, or canal
godronne. It is thus described by the dis-
coverer in the Histoire de 1'Academie des
Sciences for 1726. " I have discovered a small
canal surrounding the crystalline, which I call
the circular canal godronne; it can be seen
only by inflating it, and when filled with air it
forms itself into folds similar to the ornaments
on silver plate, called for this reason Vaiselle
godronne. It is formed by the doubling of the
hyaloid membrane, which is contracted into
cells at equal distances by little canals which
traverse it, and which do not admit of the
same degree of extension as the membrane,

EYE.

193

which is very feeble; it thus becomes godronne.
If the crystalline be removed from its capsule
without injuring the membrane which forms
this canal, these godronne folds are not formed by
inflation or only in a very slight degree, but the
canal becomes larger. It is in man commonly
a line and a quarter, a line and a half or two lines
in breadth, and not larger in the ox." An-
nexed is a representation of this canal of Petit
on a large scale.

Ji. 115.

Fig. 116.

As the nature of the connection between
the choroid and the hyaloid membrane, the
formation of the posterior chamber of the
aqueous humour, and the structure of this
canal of Petit, have been the subject of contro-
versy, I venture to introduce here an extract
on this subject from the paper published by
me in the Medico-Chirurgical Transactions.

" If the sclerotic, choroid, iris, and retina
be removed one or two days after death, leaving
the vitreous humour with the lens embedded
on its anterior part, we observe a number of
stria on the vitreous humour, converging
towards the circumference of the lens, cor-
responding in number, size, and form to the
ciliary processes, giving the same appearance
collectively that the circle of ciliary processes
or corpus ciliare does on the choroid, and nar-
rowed towards the nasal side as the corpus
ciliare is. This appearance has been noticed
by most authors, but some describe it as
arising merely from the marks left by the
ciliary processes, while others consider these
stria of the same nature as those productions
of the choroid, and call them the ciliary pro-
cesses of the vitreous humour ; it is the corona
cifiaris of Camper and Zinn. If we remove
the black pigment with a camel-hair pencil, we
leave those productions on the vitreous humour
more distinctly marked than when covered by
the colouring matter, and presenting all the
characters above stated, commencing behind
with a well-defined margin, and terminating
anteriorly by attachment to the capsule of the
lens, the furrows between them capable of
receiving the ciliary processes of the choroid,
and the folds calculated to be lodged in the
corresponding furrows of these processes. The
annexed figure is a representation of the vitreous
humour of the human eye thus treated.

" If the cornea and iris be removed from a
human eye within a few hours after death, a
dark circle surrounding the lens, between it
and the anterior extremities of the ciliary pro-
cesses, may be observed : this is the part of
the corona ciliaris of the vitreous humour to
which the ciliary processes of the choroid do
not extend, which appears dark on account of
its perfect transparency ; the converging stria
are evident, even on this part where the ciliary
processes are not insinuated, interrupting the
view if we attempt to look into the bottom of
the eye by the side of the lens. It is, in my
opinion, therefore certain, that part of the
vitreous humour enters into the formation of
the posterior chamber of the aqueous humour.
The demonstration of this fact is, however,
attended with difficulty, because the flaccidity
arising from even slight evaporation of the
fluids of the eye permits the ends of the ciliary
processes which present themselves in the
posterior chamber of the aqueous humour to
fall towards the circumference of the lens, and
appear attached there. For myself I can say
that having made the dissection in the way just
pointed out, the eye of course in water, and
beneath one of those globular vessels which
I formerly described, I could see to the bottom
of the eye through the space in front of the
vitreous humour, between the ciliary processes
and the margin of the lens ; this space is,
however, perhaps larger in some individuals
than in others. Each fold of the corona ciliaris
of the vitreous humour seems to consist of two
layers of hyaloid membrane, capable of being
separated one from the other byinflation, and ad-
mitting of communication with each other round
the lens. It appears to me that the canal of Petit
or canal godronne is formed in consequence of
these folds receiving the injected air one from
the other ; it is, however, generally described
as being formed by the membrane of the
vitreous humour splitting at the circumference
of the lens, one layer going before and the
other behind that body, the canal existing
between these two layers and the capsule of
the lens. That the capsule of the lens has no
share in the formation of the canal of Petit, I
conclude from filling this canal with air, and
allowing the part to remain for some days in
water, and then with great care removing the
lens included in its capsule ; this I do not find,
however, causes the air to escape from the cells,
but leaves them presenting nearly the original
appearance ; and after the air has escaped, I
can pass a small probe all round in this canal,

o

194

EYE.

raising by this means the folds from the hyaloid
membrane. It is difficult, however, to pre-
serve the air in these folds for any length of
time under water, because the tendency of
the air to ascend causes the rupture of the
membrane, by which it is allowed to escape.
After the lens, included in its proper capsule,
has been detached from its situation on the
vitreous humour, the space it occupied pre-
sents the appearance of a circular depression,
surrounded by those productions of the hyaloid
membrane of which I have just spoken ; the
vitreous humour remaining in every respect
perfect, notwithstanding this abstraction of the
lens." '

M. Ribes, in the Memoires de la Socie"te
Medicale d'Emulation for 1816, describes the
ciliary processes of the vitreous humour as
follows. " At the anterior part of the vitreous
humour, and at a short distance from the cir-
cumference of the crystalline, may be seen a
ciliary body almost altogether similar to that
of the choroid, and which has been named by
anatomists corona ciliaris, but no writer has
hitherto pointed out its structure, or the impor-
tant office it appears to perform. Each of
these processes has a margin adherent to the
vitreous humour, and encroaches a little on the
circumference of the lens. It appears to me
impossible to ascertain whether the surfaces are
reticulated, but they are villous. The free
margin is obviously fringed, and presents
nearly the variety of appearance observed in
the fringes of ciliary processes (of the choroid)
of different animals examined by me, except
that the summits are black ; the interval which
separates each process of the vitreous humour
is a species of depressed transparent gutter.
The black colour of the free margins and the
transparency of the space which separates each
ciliary process adorns the anterior part of the
vitreous humour with a circle remarkable for
its agreeable effect, and which has been com-
pared to the disc of a radiated flower." Dr.
Knox, in a communication made to the Royal
Society of Edinburgh, at the same time that
mine was made to the Medico-Chirurgical
Society, describes the ciliary processes of the
choroid as follows : u In whatever way, the
membrane or assemblage of membranes pro-
ceeds forwards to be inserted into the circum-
ference of the capsule of the lens, forming in
its passage numerous longitudinal folds, and
small projecting fimbriated bodies, by which,
in a natural state, the transparent humours are
connected with the superjacent ciliary body (of
the choroid) ; when examined with a good
glass, these folds are remarkably distinct, and
the whole bears the closest resemblance in its
distribution to the true ciliary body and pro-
cesses. I have, therefore, ventured to call
them the internal or transparent ciliary body,
or the ciliary body of the hyaloid membrane,
in contradistinction to that of the choroid." It
must not be forgotten that these ciliary pro-
cesses of the hyaloid membrane were described
by Monro in his Treatise on the Eye, and are
strongly marked in a coarsely executed plate.
lie considered that the retina was continued, to

the lens, and describes its course under the
ciliary processes of the choroid ; thus " on ex-
amining the retina with still greater accuracy,
it appears that it has exactly the same number
of folds or doublings that the choroid coat has;
for it enters double between the ciliary pro-
cesses, nearly in the same way that the pia
mater enters into the coats of the brain. The
furrows and doublings of the retina, which, if
we are to use the favourite term ciliary, may
be called its ciliary processes, make an impres-
sion on the anterior part of the vitreous hu-
mour." The structure alluded to was also
observed by Hovius nearly an hundred years
before.

From the preceding observations respecting
the ciliary processes of the vitreous humour, it
may justly be inferred that the ciliary pro-
cesses of the choroid, and these ciliary pro-
cesses of the vitreous humour, are of the same
nature, differing only in those of the choroid
receiving red blood, while those of the vitreous
humour receive a transparent fluid by their
bloodvessels. The adaptation of these two
circles of folds to each other appears to be a
most beautiful example of mechanical con-
struction occurring in soft parts : it is a species
of dovetailing of the one structure into the
other, by which an intimate union is secured
between one part of considerable strength and
another of extreme delicacy. A connexion
equally perfect is established between the ex-
ternal surface of the choroid at its margin, and
the corresponding margin of the sclerotic, by
means of the ciliary ligament; in fact, with-
out these two provisions of ciliary ligament
and ciliary processes, and their application
between the sclerotic, choroid, and vitreous
humour, the chambers of the eye must be
imperfectly constructed, and the optical me-
chanism of the organ defective. It is the
mechanical bond between these dissimilar parts
which perfects the chamber of aqueous humour,
and prevents that fluid from escaping, either
between the sclerotic and choroid, or between
the choroid and vitreous humour.

Of the crystalline lens. — It has been al-
read*y stated, that there is a double convex
lens within the sphere of the eye, at a short
distance behind the external lens or cornea.
This is the crystalline lens or crystalline
humour, which gives additional convergence
to the rays of light transmitted through the
pupil. It is placed in a depression, formed for
its reception on the anterior, compressed, or
truncated portion of the vitreous humour,
where that body approaches the back of the
iris, and constitutes part of the boundaries of
the posterior chamber of the aqueous humour.
In this depression it adheres firmly to the hya-
loid membrane, and from the vessels of that
structure derives its nutriment.

This double convex lens does not present the
same curvature on both surfaces, the anterior
being less curved than the posterior, in the
ratio of about 4 to 3. Attempts have been made
to determine with accuracy the nature of these
curvatures, first by Petit, and subsequently by
Wintringham, Chossat, ana! others. The re-

EYE.

195

suits of the numerous experiments of Petit lead
to the conclusion, that the anterior curvature is
that of a portion of a sphere from six to seven
lines and a half in diameter, the posterior that of
a sphere of from five to six lines and a quarter.
From the same source it appears that the dia-
meter is from four lines to four lines and a half,
the axis or thickness about two lines, and the
weight three or four grains. I am, however,
inclined to agree with the observation of Porter-
field, that, " as it is scarce possible to measure
the crystalline and the other parts of the eye
with that exactness that may be depended on,
all nice calculations founded" on such measures
must be fallacious and uncertain, and, therefore,
should, for the most part, be looked on rather
as illustrations than strict demonstrations of the
points in question." The method by which
Petit arrived at these results must render them
of doubtful value, the curvatures having been
determined by the application of brass plates
cut to the requisite form. The results of
Chossat's experiments, conducted with great
care, and with the assistance of the megascope,
are thus stated by Mr. Lloyd in his Treatise on
Optics : " This author has found that the cornea
of the eye of the ox is an ellipsoid of revolution
round the greater axis, this axis being inclined
inwards about 10°. The ratio of the major
axis to the distance between the foci in the
generating ellipse he found to be 1.3 ; and this
agreeing very nearly with 1.337, the index of
refraction of the aqueous humour, it follows
that parallel rays will be refracted to a focus, by
the surface of this humour, with mathemathical
accuracy. The same author found likewise that
the two surfaces of the crystalline lens are ellip-
soids of revolution round the lesser axis ; and it is
somewhat remarkable that the axes of these sur-
faces do not coincide in direction either with each
other, or with the axis of the cornea, these axes
being both inclined outwards, and containing
with each other, in the horizontal section in
which they lie, an angle of about 5°." It must
not be forgotten that these observations apply
to the crystalline of the ox, not to that of nun,
and also that, as Chossat himself admits, the
evaporation of the fluid part of the lens, or the
absorption or imbibition of the water in which
it is immersed, may materially alter the curva-
ture. I cannot myself believe it possible to
separate a fresh lens in its capsule perfectly
from the hyaloid membrane without injuring
its structure, and endangering an alteration in
its form. Haller states that Kepler considered
the anterior convexity to approach to a sphe-
roid, and the posterior to a hyperbolic cone.
Wintringham states the results of his inquiries
as to this matter as follows : — " In order to
take the dimensions of the eye of an ox, I
placed it on a horizontal board and applied
three moveable silks, which were kept extended
by small plummets, so as to be exact tangents
to the arch of the cornea, as well at each can-
thus, as at the vertex ; then applying a very
exactly divided scale, I found that the chord of
the cornea was equal to 1.05 of an inch, the
versed sine of this chord to be 0.29, and con-
sequently the radius of the cornea was equal to
0.620215 of an inch. I then carefullv took off

the cornea, and replaced the eye as before, and
found, by applying one of the threads as a tan-
gent to the vertex of the crystalline, that the
distance between this and the vertex of the cor-
nea was 0.355 of an inch. Afterwards I took
the crystalline out without injuring its figure,
or displacing the capsula, and then applying
the threads to each surface of this humour, as
was done before to the arch of the cornea, I
found that the chord of the crystalline was 0.74
of an inch, and its versed sine, with respect to
the anterior surface, to be 0.1 89 of an inch, and
consequently the radius of this surface was
0.45665 of the same. In like manner the
versed sine to the same chord, with respect to
the posterior surface of the crystalline, I found
to be equal to 0.38845 of an inch. Lastly, I
found the axis of the crystalline and that of the
whole eye from the cornea to the retina to be
0.574, 2.21 respectively ." Whatever doubts
may be entertained respecting the accuracy of
the measurements of the lens, there can be none
that the form is different at different periods of
life, in the human subject. It also appears to
differ in different individuals at the same period
of life, and probably the curvature is not the
same in both eyes. In other animals the dif-
ference in form is most remarkable. In the
human foetus, even up to the ninth month, it is
almost spherical. Petit states that he found
the anterior curvature in a fcetus of seven
months, a portion of a sphere of three lines
diameter, and the posterior of two and a half,
and the same in a new-born infant. In an in-
fant eight days old, the anterior convexity was
a portion of a sphere of four lines, and the
posterior of three. All anatomists concur in
considering the lens to approach more to a
sphere at this period. In childhood the curva-
tures still continue much greater than in ad-
vanced life ; from ten to twenty probably de-
crease, and from that period to forty, forty-five,
or fifty, remain stationary, when they become
much less ; being, according to the tables of
Petit, portions of spheres from seven to even
twelve lines in diameter, and on the posterior
of six or eight. Every day's observation proves
that the lens becomes flattened, and its curva-
tures diminished as persons advance in life. It
is seen in dissection, when extracted by opera-
tion, and even during life; the distance between
its anterior surface and the back of the iris be-
ing so great in some old persons, that the sha-
dow of the pupil may be seen upon it, while at
an earlier period it actually touches that part of
the membrane. This diminution of the curva-
tures of the lens commences about the age of
forty-five. Petit found the anterior convexity
varying from a sphere of about seven to twelve
lines diameter, and the posterior from five to
eight in persons from fifty to sixty-five years of
age. The alteration in power of adaptation,
and the indistinctness of vision of near objects
which takes place at this period, is probably to
be attributed to this cause, although a diminu-
tion of the muscular power of the iris, and con-
sequent inactivity of the pupil, may contribute
to the defect. It is also to be recollected that
the density of the lens is much increased at this
period, and that the young person whose lens

o2

196

EYE.

presents greater curvatures does not require
concave glasses, as the old person requires con-
vex ones. The state of the eye, after the re-
moval of the lens by operation for cataract,
proves that it is a part of the organ essentially
necessary for correct vision. When the eye is
in other respects perfect, without any shred of
opaque capsule, any irregularity or adhesion of
the pupil, or any alteration in the curvature of
the cornea, as in young persons who have had
the lens properly broken up with a fine needle
through the cornea, vision is so good for distant
objects, that such persons are able to pursue
their common occupations, and walk with safety
through crowded streets, but they require the
use of a convex lens, of from three and a half to
five inches focus, for reading or vision of near;
old persons, however, generally require convex
glasses on all occasions after the removal of the
lens. That the curvatures of the lens are fre-
quently different in different individuals may
be inferred from the frequency of short sight,
or defective power of adaptation, not attributa-
ble to any peculiarity of the cornea. Petit
states that he found lenses of which the two
convexities were equal, and others of which the
anterior was greater than the posterior, and
more than once, one more convex on its ante-
rior surface in one eye, while that in the other
eye was in a natural state. He also occasion-
ally found the lens as convex in the advanced
period of life as in youth. I have repeatedly
observed the perfection of vision and power of
adaptation much greater in one eye than the
other in the same individual, without any defect
of the cornea, pupil, or retina ; and occasionally
have found young persons requiring the com-
mon convex glasses used by persons advanced
in life, and old persons becoming near-sighted,
and requiring concaves. The annexed letters
shew the difference of curvature at the different
periods of life, as represented by Sbmmerring.
A is the lens of the foetus; B, that of a child of
six years of age ; and C, that of an adult.

The colour of the lens is also different at
different periods of life. In the foetus it is
often of a reddish colour; at birth and in in-
fancy it appears slightly opaque or opaline ; in
youth it is perfectly transparent; and in the
more advanced periods of life acquires a yel-
lowish or amber tint. These varieties in colour
are not visible, unless the lens be removed
from the eye, until the colour becomes so deep
an old age as to diminish the transparency,
when it appears opaque or milky, or resembling
the semi transparent horn used for lanterns. The
hard lenticular cataract of advanced life appears
to be nothing more than the extreme of this
change of colour, at least when extracted and
placed on white paper it presents no other
disorganization ; but the lens of old persons,
when seen in a good light and with a dilated
pupil, always appears more or less opaque, al-

though vision remains perfect. The depth of
colour is sometimes so great, without any
milkiness or opacity, that the pupil appears
quite transparent although vision is lost. This
is perhaps the state of lens vaguely alluded to
by authors under the name of black cataract.

The consistence of the lens varies as much
as its colour. In infancy it is soft and pulpy,
in youth firmer, but still so soft that it may be
crushed between the finger and thumb, and in
old age becomes tough and firm. Hence it is
that in the earlier periods of life cataracts may
be broken up completely into a pulp, and
absorbed with certainty, while in old persons
they adhere to the needle, unless very deli-
cately touched, and are very liable to be de-
tached from the capsule and thrown upon the
iris, causing the destruction of the organ. On
this account, therefore, the operation of extrac-
tion must generally be resorted to in old per-
sons labouring under this form of cataract,
while the complete division of it with the
needle and exposure of the fragments to the
contact of the aqueous humour secures its
removal by absorption in young persons. It
must not, however, be forgotten that the softer
lenticular cataract occasionally occurs in ad*
vanced life.

The crystalline lens is a little heavier than
water. Porterfield, from the experiments of
Bryan Robinson, infers that the specific gra-
vity of the human lens is to that of the other
humours as eleven to ten, the latter being
nearly the same as water; and Wintringham,
from his experiments, concludes that the den-
sity of the crystalline is to that of the vitreous
humour in the ratio of nine to ten; the spe-
cific gravity of the latter being to water as
10024 to 10000. The density of the lens is
not the same throughout, the surface being
nearly fluid, while the centre scarcely yields to
the pressure of the finger and thumb, especially
in advanced life. Wintringham found the spe-
cific gravity of the centre of the lens of the ox
to exceed that of the entire lens in the propor-
tion of twenty-seven to twenty-six. The re-
fractive power is consequently greater than that
of the other humours. On this head Mr.
Lloyd, in his Optics, says, " In their refrac-
tive power, the aqueous and vitreous humours
differ very little from that of water. The re-
fractive index of the aqueous humour is 1.337,
and that of the vitreous humour 1.339; that of
water being 1.336. The refractive power of
the crystalline is greater, its mean refracting
index being 1.384. The density of the crystal-
line, however, is not uniform, but increases
gradually from the outside to the centre. This
increase of density serves to correct the aber-
ration by increasing the convergence of the
central rays more than that of the extreme parts
of the pencil." Dr. Brewster, in his Treatise
on Optics, says, a I have found the following
to be the refractive powers of the different
humours of the eye, the ray of light being
incident upon them from the eye : aqueous
humour 1.336; crystalline, surface 1.3767,
centre 1.3990, mean 1.3839; vitreous humour
1.3394. But as the rays refracted by the
aqueous humour pass into the crystalline, and

EYE.

those from the crystalline into the vitreous
humour, the indices of refraction of the sepa-
rating surface of these humours will be, from
the aqueous humour to the outer coat of the
crystalline 1.0466, from the aqueous humour
to the crystalline, using the mean index, 1.0353,
from the vitreous to the outer coat of the cry-
stalline 1.0445, from the vitreous to the crystal-
line, using the mean index, 1.0332." Dr.
Young says, " On the whole it is probable
that the refractive power of the centre of the
human crystalline, in its living state, is to that
of water nearly as 18 to 7; that the water im-
bibed after death reduces it to the ratio of 21 to
20 ; but that on account of the unequable den-
sity, ks effect in the eye is equivalent to a
refraction of 14 to 13 for its whole size/*

Respecting the chemical composition of the
lens, Berzelius observes, that " the liquid in
its cells is more concentrated than any other
in the body. It is completely diaphanous and
colourless, holding in solution a particular
animal matter belonging evidently to the class
of albuminous substances, but differing from
fibrine in not coagulating spontaneously, and
from albumen, inasmuch as the concentrated
solution, instead of becoming a coherent mass
on the application of heat, becomes granulated
exactly as the colouring matter of the blood
when coagulated, from which it only differs in
the absence of colour. All those chemical
properties are the same as those of the co-
louring matter of the blood. The following
are the principles of which the lens is com-
posed : peculiar coagulable albuminous matter
35.9, alcoholic extract with salts 2.4, watery
extract with traces of salts 1.3, membrane form-
ing the cells 2.4, water 58.0.

From the preceding observations it might
reasonably be supposed that the lens is com-
posed of a homogeneous material, such as al-
bumen or gelatine, more consolidated in the
centre than at the circumference; but this is
not the case; on the contrary, it exhibits as
much of elaborate organization as any other
structure in the animal economy. It consists
of an outer case or capsule, so totally different
from the solid body contained within it, that
they must be separately investigated and de-
scribed. The body of the lens, it has been
already stated, consists of certain saline and
animal ingredients combined with more than
their weight of water, and when perfectly
transparent presents the appearance of a tena-
cious unorganized mass; but when rendered
opaque by disease, loss of vitality, heat, or im-
mersion in certain fluids, its intimate structure
becomes visible. If the lens with the capsule
attached to the hyaloid membrane be removed
from the eye and placed in water, the following
day it is found slightly opaque or opaline, and
split into several portions by fissures extending
from the centre to the circumference, as seen
in Jig. 118. This appearance is rendered
still more obvious by immersion in spirit, or
the addition of a few drops of acid to the
water. If a lens thus circumstanced be al-
lowed to remain some days in water, it con-
tinues to expand and unfold itself, and if
delicately touched and opened by the point of

a needle, and carefully transferred to spirit,
and as it hardens is still more unravelled by
dissection, it ultimately presents a remarkable
fibrous or tufted appearance, as represented in
the figure below, drawn by me some years ago
from a preparation of the lens of a fish thus
treated (the Lophius piscatorius). The three
annexed figures represent the structure of the
lens above alluded to : A is the human crystal-
line in its natural state; B, the same split up into
its component plates ; and C, unravelled in
the fish.

Fig. 118.

B

This very remarkable structure of the body
of the lens appears to have been first accu-
rately described by Leeuwenhoek, subse-
quently by Dr. Young, and still more recently
by Sir David Brewster. Leeuwenhoek says,
" It may be compared to a small globe or
sphere, made up of thin pieces of paper laid
one on another, and supposing each paper to
be composed of particles or lines placed some-
what in the position of the meridian lines on a
globe, extending from one pole to the other."
Again he says, " With regard to the before-
mentioned scales or coats, I found them so
exceedingly thin, that, measuring them by my
eye, I must say that there were more than two
thousand of them lying one upon another."
" And, lastly, I saw that each of these coats
or scales was formed of filaments or threads
placed in regular order, side by side, each coat
being the thickness of one such filament." The
peculiar arrangement of these fibres he describes
as follows : " Hence we may collect how ex-
cessively thin these filaments are; and we shall
be struck with admiration in viewing the won-
derful manner they take their course, not in a
regular circle round the ball of the crystalline
humour, as I first thought, but by three dif-
ferent circuits proceeding from the point L,
which point I will call their axis or centre.
They do not on the other side of the sphere
approach each other in a centre like this at L,
but return in a short or sudden turn or bend,
where they are the shortest, so that the filaments
of which each coat is composed have not in reality
any termination or end. To explain this rnore
particularly, the shortest filaments, M K, H N,
and O F, which fill the space on the other
side of the sphere, constitute a kind of axis or
centre, similar to this at L, so that the fila-
ments M K, having gone their extent, and filled
up the space on the other side, in like manner
as is here shewn by the lines ELI, return
back and become the shortest filaments H N.
These filaments H N, passing on the other side

198

EYE.

of the sphere, again form another axis or centre,
and return in the direction O F, and the fila-
ments O F, again on the other side of the
sphere, collect round a third centre, and thence
return in the direction K M ; so that the fila-
ments which are on this side of the sphere
collect round a third centre, and thence return
in the direction K M; so that the filaments
which are on this side the shortest, on the other
side are the longest, and those which there are
the shortest are here the longest/* Annexed is
Leeuwenhoek's representation (Jig. 1 19).

Fig. 119.

Sir Pavid Brewster says that the direction of
the fibres is different in different animals; the
simplest arrangement being that of birds, and
the cod, haddock, and several other fishes. In
it the fibres, like the meridians of a globe, con-
verge to two opposite points of a spheroidal or
lenticular solid, as in the annexed figure.

Fig. 121.

Dr. Young differs from Leeuwenhoek as to
the arrangement of the fibres and other parti-
culars, and in his last paper corrects the de-
scription given by himself in a former one ; he
says, " The number of radiations (of the fibres)
is of little consequence , but I find that in the
human crystalline there are ten on each side,
not three, as I once from a hasty observation
concluded." " In quadrupeds the fibres at
their angular meeting are certainly not conti-
nued as Leeuwenhoek imagined." Beneath is
Dr. Young's last view of the arrangement of
the fibres, which Dr. Brewster has shown to be
incorrect, but the introduction of which is jus-
tified by the source from which it is derived.

Fig. 120.

The second or next simplest structure he
detected in the salmon, shark, trout, and other
fishes ; as well as in the hare, rabbit, and por-
poise among the mammalia; and in the alli-
gator, gecko, and others among reptiles. Such
lenses have two septa at each pole, as in the
annexed figure.

Fig. 122.

The third or more complex structure exists
in mammalia in general, " in which three septa
diverge from each pole of the lens, at angles of
1 20°, the septa of the posterior surface bisect-
ing the angles formed by the septa of the ante-
rior surface, as in the annexed figure (fig. 12 3).

Fig. 123.

The mode in which these fibres are laterally
united to each other is equally curious. Sir
David Brewster says that he ascertained this in
looking at a bright light through a thin lamina
of the lens of a cod, when he observed two
faint and broad prismatic images, situated in a
line exactly perpendicular to that which joined
the common coloured images. Their angular
distance from the central image was nearly five
times greater than that of the first ordinary
prismatic images, and no doubt whatsoever
could be entertained that they were owing to a
number of minute lines perpendicular to the
direction of the fibres, and whose distance did
not exceed the ^dth of an inch. Upon ap-
plying a good microscope to a well-prepared
lamina, the two fibres were found united by a
series of teeth exactly like those of rack work,
the projecting teeth "of one fibre entering into
the hollows between the teeth of the adjacent
one, as in Jig. 124.

Fig. 124.

I have said that the lens consists of an outer
ease or capsule totally different from the solid

EYE. 199

body contained within it. This capsule is
strong, elastic, and perfectly transparent. In
the paper to which I have alluded in the Me-
dico-Chirurgical Transactions, I gave the fol-
lowing detailed description of its nature and
properties : —

" The real nature of the capsule of the lens
has not, I think, been sufficiently attended to;
its thickness, strength, and elasticity, have cer-
tainly been noticed, but have not attracted that
attention which a fact so interesting, both in a
physiological and pathological point of view,
deserves. That its structure is cartilaginous, I
should conclude, first, from its elasticity, which
causes it to assume a peculiar appearance when
the lens has been removed, not falling loose
into folds as other membranes, but coiled in
different directions ; or if the lens be removed
by opening the capsule behind, and with-
drawing it through the vitreous humour, allow-
ing the water in which the part is immersed to
replace the lens, the capsule preserves in a
great degree its original form, especially in the
eye of the fish; secondly, from the density and
firmness of its texture, which may be ascer-
tained by attempting to wound it by a cataract
needle, by cutting it upon a solid body, or
compressing it between the teeth; thirdly, from
its permanent transparency, which it does not
lose except on the application of very strong
acid or boiling water, and then only in a slight
degree ; maceration in water for some months,
or immersion in spirit of strength sufficient to
preserve anatomical preparations, having little
or no effect upon it. If the lens be removed
from the eye of a fish dressed for the table, the
capsule may be raised by the point of a pin,
and be still found almost perfectly transparent.
This combination of density and transparency
gives the capsule a peculiar sparkling appear-
ance in water, in consequence of the reflection
of light from its surface, resembling a portion
of thin glass which had assumed an irregular
form while soft ; this sparkling I consider very
characteristic of this structure. The properties
just enumerated appear to me to distinguish it
from every other texture but cartilage; still,
however, it may be said that cartilage is not
transparent, but even the cartilage of the joints
is semi-transparent, and, if divided into very
thin portions, is sufficiently pellucid to permit
the perception of dark objects placed behind
it, and we obtain it almost perfectly transparent
where it gives form to the globe of the eye, as
in the sclerotic of birds and fishes. If the soft
consistence, almost approaching to fluidity, of
the external part of the lens, be considered, the
necessity of a capsule capable itself of pre-
serving a determinate form is obvious. If the
lens were enclosed in a capsule such as that
which envelopes the vitreous humour, its sur-
face could not be expected to present the ne-
cessary regular and permanent curvature ; nor
could we expect that if the form of the lens
were changed, it could be restored without this
provision of an elastic capsule."

The capsule is liable to become opaque and
constitute cataract, as the body of the lens is.
These capsular cataracts are easily distinguished

200

EYE.

from the lenticular. They never present the
stellated appearance frequently observed when
the texture of the opaque lens opens in the cap-
sule as it does when macerated in water, nor the
uniform horny or the milky blue appearance of
common lenticular cataract. The opacity in
capsular cataract exists in the shape of irregular
dots or patches, of an opaque paper-white ap-
pearance, and when touched with the needle are
found hard and elastic, like indurated cartilage,
the spaces between the specks of opacity fre-
quently remaining perfectly transparent.

It appears to be generally assumed by writers
on anatomy that a watery fluid is interposed
between the body of the lens and its capsule,
from an incidental observation of Morgagni
when discussing the difference in density be-
tween the surface and centre of the lens; hence
it has been called the aqua Morgagni. The
observation of this celebrated anatomist, in his
Adversaria Anatomica, which has led to the
universal adoption of this notion, is, however,
merely that upon opening the capsule he had
frequently found a fluid to escape. " Deinde
eadem tunica in vitulis etiam, bobusque sive
recens, sive non ita recens occisis perforata,
pluries animadverti, illico humorem quendam
aqueum prodire : quod et in homine observare
visus sum, atque adeo credidi, hujus humoris
secretione prohibita, crystallinum siccum, et
opacum fieri fere ut in extracto exsiccatoque
crystalline contingit." He does not, however,
subsequently dwell upon or insist upon the
point. I do not believe that any such fluid
exists in a natural state, but that its accumula-
tion is a consequence of loss of vitality ; the
water combined with the solid parts of the lens
escaping to the surface and being detained by
the capsule, as occurs in the pericardium and
other parts of the body. In the eyes of sheep
and oxen, when examined a few hours after
death, not a trace of any such fluid can be
detected, but after about twenty-four hours it
is found in considerable quantity. In the
human eye a fluid sometimes accumulates in
the capsule, constituting a particular form of
cataract, which presses against the iris, and
almost touches the cornea ; but such eyes are,
I believe, always unsound. From this erro-
neous notion of an interposed fluid between
the lens and its capsule has arisen the adop-
tion of an unsustained and improbable conclu-
sion, that the lens has no vital connexion with
its capsule, and consequently must be produced
and preserved by some process analogous to
secretion. Respecting this matter I have ob-
served, in the paper above alluded to, " The
lens has been considered by some as having no
connexion with its capsule, and consequently
that its formation and growth is accomplished
without the assistance of vessels; such a notion
is so completely at variance with the known
laws of the animal economy, that we are justi-
fied in rejecting it, unless supported by un-
questionable proof. The only reasons which
have been advanced in support of this conclu-
sion are, the failure of attempts to inject its
vessels, and the ease with which it may be
separated from its capsule when that mem-

brane is opened. These reasons are far from
being satisfactory; it does not necessarily
follow that parts do not contain vessels, be-
cause we cannot inject them; we frequently
fail when theie can be no doubt of their exist-
ence, especially where they do not carry red
blood. I have not myself succeeded in in-
jecting the vessels of the lens, but I have not
repeated the trial so often as to make me
despair of accomplishing it, more especially
as Albinus, an anatomist whose accuracy is
universally acknowledged, asserts, that after a
successful injection of the capsule of the lens,
he could see a vessel passing into the centre of
the lens itself. Lobe, who was his pupil,
bears testimony to this. The assertion that
the lens is not connected with its capsule, I
think I can show to be incorrect; it has been
made from want of care in pursuing the inves-
tigation, and from a notion that a fluid exists
throughout between the lens and its capsule.
When the capsule is opened, its elasticity
causes it to separate from the lens ; especially
if the eye be examined some days after death,
or has been kept in water, as then the lens
swells, and often even bursts the capsule and
protrudes through the opening, by which the
connexion is destroyed. I have however satis-
fied myself that the lens is connected with its
capsule (and that connexion by no means
slight) by the following method. I remove
the cornea and iris from an eye, within a few
hours after death, and place it in water, then
with a pair of sharp-pointed scissors I divide
the capsule all round at the circumference of
the lens, taking care that the division is made
behind the anterior convexity, so that the lens
cannot be retained by any portion of the cap-
sule supporting it in front. I next invert the
eye, holding it by the optic nerve, when I find
that the lens cannot be displaced by agitation,
if the eye be sufficiently fresh. In the eye of
a young man about six hours dead, I found
that, on pushing a cataract needle into the lens,
after the anterior part of the capsule had been
removed, I could raise the eye from the bottom
of the vessel, and even half way out of the
water, by the connexion between the lens and
its capsule. It afterwards required consider-
able force to separate them, by passing the
needle beneath the lens, and raising it from its
situation. I believe those who have been in
the habit of performing the operation of ex-
traction, have occasionally encountered consi-
derable difficulty in detaching the lens from
its situation after the capsule had been freely
opened, this difficulty I consider fairly refer-
able to the natural connexion just noticed."
When the lens enclosed in its capsule is de-
tached from the hyaloid membrane, the con-
nexion between it and the capsule is destroyed
by the handling, and, in consequence, it moves
freely within that covering, affording to those
who believe that there is no union between the
two surfaces fallacious evidence in support of
that opinion, which, if not sustained by better
proof, should be abandoned. Dr. Young in-
sists upon the existence of the natural con-
nexion by vessels and even by nerves between

EYE,

201

the lens and its capsule ; he says, " The cap-
sule adheres to the ciliary substance, and the
lens to the capsule, principally in two or three
points ; but I confess I have not been able to
observe that these points are exactly opposite
to the trunks of nerves; so that probably the
adhesion is chiefly caused by those vessels
which are sometimes seen passing to the cap-
sule in injected eyes. We may, however, dis-
cover ramifications from some of these points
upon and within the substance of the lens,
generally following a direction near to that of
the fibres, and sometimes proceeding from a
point opposite to one of the radiating lines of
the same surface. But the principal vessels of
the lens appear to be derived from the central
artery, by two or three branches at some little
distance from the posterior vortex, which I
conceive to be the cause of the frequent adhe-
sion of a portion of a cataract to the capsule
about this point ; they follow nearly the course
of the radiations and then of the fibres ; but
there is often a superficial subdivision of one
of the radii at the spot where one of them
enters." The great size of the vessels distri-
buted on the back of the capsule in the foetus
strengthens the conclusion that the lens is fur-
nished with vessels as the rest of the body.
When the eye of a foetus of seven or eight
months is finely injected, a branch from the
central artery of the retina is filled and may be
traced through the centre of the vitreous hu-
mour to the back of the capsule, where it
ramifies in a remarkably beautiful manner,
assuming, according to Sommerring, a stellated
or radiating arrangement. Zinn declares that
he found branches from this vessel penetrating
the lens : " Optime autem placet observatio
arteriolae lentis, in oculo infantis, cujus vasa
cera optime erant repleta, summa voluptate
mihi visae, quam prope marginem ad convexi-
tatem posteriorem dilatam, duobus ramulis
perforata capsula in ipsam substantiam lentis
profunde se immergentem cortissime con-
spexi." He also quotes the authority of
Ruysch, Moeller, Albinus, and Winslow, as
favouring the same view. Against such au-
thority I find that of the French systematic
writer Bichat advanced ; but on such a point
his opinion is of little

Fig. 125.

value. Annexed is
Zinn's representa-
tion of the distribu-
tion of the branch
of the central artery
on the back of
the capsule, from
a preparation in
Lieberkuhn's mu-
seum. Similar fi-
gures have been
given by Albinus,
Sommerring, and
Sir Charles Bell.

Of the aqueous humour. — In the preliminary
observations at the commencement of this
article, I stated that a cavity or space filled
with water exists between the cornea and crys-
talline lens, in which space the iris is extended,
with its aperture or pupil, to moderate the

quantity of light, and interrupt the passage of
the extreme rays. It is bounded anteriorly by
the concave inner surface of the cornea, and
posteriorly by the crystalline lens and other
parts, and is necessarily divided into two
spaces or chambers by the iris. That in front
of the iris, called the anterior chamber, 19
bounded by the concare inner surface of the
cornea anteriorly, and by the flat surface of the
iris posteriorly, which, I have already stated,
is a plane, not a convex surface, as represented
in the plates of Zinn and others. The size of
this space is necessarily small, and varies in
different individuals according to the convexity
of the cornea, which also frequently varies.
It is always, however, sufficiently large to allow
the surgeon to introduce a needle to break up
a cataract without wounding the iris or cornea.
The posterior chamber is bounded in front by
the back of the iris, and behind by the crys-
talline lens ; with that portion of the hyaloid
membrane of the vitreous humour, which is
between the anterior termination of the ciliary
processes of the choroid and the circumference
of the lens. The circumference of the pos-
terior chamber is bounded by the anterior ex-
tremities of the ciliary processes of the choroid,
as they extend from the vitreous humour to the
back of the iris. It does not appear to be
generally admitted or well understood that any
part of the hyaloid membrane of the vitreous
humour enters into the composition of the
posterior chamber of the aqueous hu-
mour, notwithstanding the decisive opinion
and accurate representation of the celebrated
Sommerring, in which I entirely concur, as I
have stated above in describing the vitreous
humour.

The size of the posterior chamber has been
the subject of much discussion and contro-
versy, and various attempts have been made
by freezing the eye and other means to deter-
mine the matter. Petit, after a careful inves-
tigation, considered that the distance between
the lens and iris was less than a quarter or half
a line, in which Haller appears to concur.
Winslow, in the Memoirs of the French Aca-
demy for 1721, insists that the iris is in contact
with the lens. Lieutaud, in his Essais Ana-
tomiques, is equally positive on this point,
and even denies altogether the existence of a
posterior chamber. The question is not an
indifferent one, inasmuch as it involves impor-
tant considerations as to operations for cataract
and inflammations of the iris. Modern ana-
tomists appear, generally, to consider the dis-
tance between the lens and iris to be greater
than it really is. Although I cannot agree
with Winslow and Lieutaud that the margin
of the pupil is always in contact with the lens,
I believe it frequently is so, especially in the
earlier periods of life, when the curvatures of
the lens are considerable. In iritis adhesions
generally take place between the margin of the
pupil and the capsule of the lens, a conse-
quence not easily accounted for, if the parts
be not in contact. In old age the lens be-
comes much flattened, and therefore retreats
from the pupil, to such a degree that the sha-

202 EVE.

dow of the iris may often be seen in a crescentic
form on a cataract ; and in such persons, whe-
ther from tins cause or from the inflammation
not being of the adhesive character, blindness
is more frequently attended with dilated pupil.
In breaking up cataracts through the cornea,
I have repeatedly satisfied myself of the con-
tact or close vicinity of the two surfaces by
placing the needle between them. The an-
nexed outline section, from the work of S6m-
merring, shews how
Fig. 1 26. sman he considered the

space between the iris
and lens, and displays
accurately how the
posterior chamber is
formed by the iris an*
teriorly, the lens pos-
teriorly, and the cili-
ary processes at the
circumference, with the
small circular portion
of the hyaloid mem-
brane of the vitreous
humour between the
ciiliary processes of
the choroid and the
circumference of the
lens.

It appears to me unaccountable why sur-
geons, with these anatomical facts before them,
still continue to introduce the needle into the
posterior chamber, to break up cataracts, in-
stead of passing it through the cornea into the
anterior chamber, where ample space exists,
and a full view is obtained of all the steps of
the operation. In doing so the needle is thrust
through opaque parts among delicate structures,
into a narrow cavity, where, hidden by the iris,
it can be used with little certainty of correct
application. At the same time, instead of
penetrating the simple structure of the cornea,
which bears injury as well as any other struc-
ture of the body, the instrument pervades the
fibrous sclerotic, a structure impatient of in-
jury and prone to inflammation, punctures the
ciliary ligament at the imminent risk of in-
juring one of the ciliary nerves or even wound-
ing the long ciliary artery, and finally passes
through one of the most vascular parts in the
body, the corpus ciliare. The practice appears
a signal instance of the influence of education,
habit, and authority in setting improvement at
defiance. The proofs afforded of the close
vicinity of the margin of the pupil to the cap-
sule of the lens, should remind the surgeon
that one of the greatest dangers to be ap-
prehended in iritis is the adhesion of these two
parts, and that one of the first steps in the
treatment should be to separate them by the
application of belladonna, which, by its pecu-
liar influence on the pupil, dilates that aper-
ture, and, consequently, brings its margin
more opposite the circumference of the lens
and at a greater distance from the prominent
central portion.

The aqueous humour, although constituting
so essential a part of the optical mechanism of
the eye, is but small in quantity ; according to

Petit not more than four or five grains. Its
specific gravity and refractive power scarcely
differ from that of water; and according to
Berzelius, 100 parts contain 98.10 of water,
1.15 of chloruret of soda with a slight trace
of alcoholic extract, 0.75 of extractive matter
soluble in water only, and a mere trace of
albumen. It is perfectly transparent, but is
said to be milky in the foetus.

The source from which this fluid is derived
has been the subject of controversy in con-
sequence of Nuck, a professor of anatomy at
Leyden, having asserted that he had discovered
certain ducts through which it was transmitted*
and published a small treatise to that effect,
which ducts were proved to be vesssels by a
cotemporary writer, Chrouet, in which deci-
sion subsequent authors have concurred. In
the present day this fluid is generally believed
to be secreted by a membrane lining the cavity,
as the fluid which lubricates the serous cavities
is secreted by their lining membranes. Al-
though this is in all probability the fact, the
circumstances are not exactly the same in both
cases. In the serous cavities, merely as much
fluid as moistens the surface is poured out,
while in the chamber of the aqueous humour
sufficient to distend the cavity is secreted. In
the serous cavities the membrane from which
they derive their name can be demonstrated ;
in the chamber of aqueous humour this can
scarcely be accomplished. I have resorted to
various methods to enable me to demonstrate
the existence of the membrane of the aqueous
humour on the back of the elastic cornea,
such as maceration, immersion in hot water,
soaking in alcohol, and treating with acids,
alkalis, and various salts, but without effect.
In describing the structure of the cornea, I
have shewn that the elastic cornea itself can-
not for a moment be considered the membrane
in question, on account of its strength, thick-
ness, elasticity, and abrupt termination; and
I do not think that the demonstration of a
serous membrane expanded on such a struc-
ture as transparent cartilage is to be expected,
inasmuch as the demonstration of the synovial
membrane on the cartilages of incrustation in
the joints is attended with much difficulty.
The pathological fact which tends most to
prove the existence of such a membrane here,
is, that in iritis, especially that of a syphilitic
character, the aqueous humour appears often
very muddy, especially in the inferior half of
the chamber ; this, however, in the latter stages
may be found to arise from a delicate speckled
opacity on the back of the cornea, which re-
mains permanently, and injures vision con-
siderably. Analogy also favours the inference
that the whole cavity of the chamber must be
lined by serous membrane, inasmuch as all
structures, of whatsoever nature they may be,
in the serous or synovial cavities, are so covered
or lined. This provision is so universal, that
if such various structure, as the elastic cornea,
iris, capsule of the lens, ciliary processes, and
hyaloid membrane, which enter into the con-
struction of the chamber of aqueous humour,
be exposed to the contact of the fluid without

EYfi.

any intervening membrane, it constitutes an
unexpected anomaly in the animal ceconomy.
The consequences of inflammation greatly
strengthen the conclusion that the cavity is
lined by a membrane of the serous character.
The slightest injuries or even small ulcers of
the cornea are frequently accompanied by effu-
sion of purulent matter into the anterior
chamber, from the extension of the inflam-
mation into that cavity, constituting the hy-
popion or onyx of the books ; and the yellow
masses which appear on the iris in syphilitic
iritis, whether they are abscesses, or as they
are called, globules of lymph, are effusions
beneath a delicate membrane, as vessels may
be seen with a magnifying glass, ramifying
over them. In iritis the rapidity with which
adhesions are formed between the margin of
the pupil and the capsule, proves that these
two structures are covered by a membrane of
this nature. In addition to all these facts the
still more conclusive one is to be adduced,
namely, that the membrane can without diffi-
culty be demonstrated on
the back of the iris, as
I have stated in speaking
of that part of the organ,
and as it is represented
in fig. 127, where the
fold of membrane stained
with black pigment is seen
turned down from that
structure.

In the preceding pages I have availed my-
self of whatever valuable and appropriate facts
in comparative anatomy I found calculated to
illustrate or explain the structure of the human
eye. There are, however, two organs in other
animals which do not exist even in the most
imperfect or rudimental state in the human
subject — the pecten or marsupium nigrum in
birds, and the choroid gland or choroid muscle
in fishes.

Of the pecten. — This organ is called pecten

from its folded form bearing some resemblance
to a comb, and mai^supium nigrum from its
resemblance in the eye of the ostrich to a black
purse, according to the anatomists of the
French Academy, who compiled the collection
of memoirs on comparative anatomy. The
organ is obviously a screen projected from
the bottom of the eye forward toward the crys-
talline lens, and, consequently, received into
a corresponding notch or wedge-shaped hollow
in the vitreous humour; it appears to be of
the same vascular structure as the choroid, and
is deeply stained with the black pigment,
which renders it perfectly opaque and imper-
vious to light. The annexed figure, from the
work of D. W. Sommerring, represents it in
the eye of the golden eagle.

Fig. 128.

Fig 127.

It is composed of a delicate membrane, highly
vascular, folded exactly like the plaits of a fan,
and when removed with sharp scissors from
the bottom of the eye, and its free margin cut
along the edge so as to allow the folds to be
pulled open, it may be spread out into a strip
of continuous riband-shaped membrane, as
seen in Jig. 129, from a paper of Sir E.
Home's in the Philosophical Transactions for
1822.

Fig. 129.

The first account I find of it is by Petit in
the M£m. de I'Acad. Roy. 1735. He says it
is a trapezium or trapezoid, five lines long at
the base, and three lines and a half deep, com-
posed of parallel fibres, and that a fine trans-
parent filament runs from the anterior superior
an^le to the capsule of the crystalline lens,
not easily seen on account of its transparency,
and that sometimes the angle itself is attached
to the capsule near its margin. Haller, in his
work " Sur la formation du cceur dans le

poulet," describes it as follows: — " It is a
black membrane folded at very acute angles, as
the paper of a fan, upon which transparent
vessels are expanded; it generally resembles
the ciliary processes. It originates from the
sclerotic in the posterior part of the eye by a
serrated line, pierces the choroid, retina, and
vitreous humour to attach itself to the side of
the capsule of the crystalline, very near the
corona ciliaris. The posterior extremity is
broad, and the anterior narrows till it becomes

204

EYE.

adherent to the capsule of the lens by an inser-
tion a little narrower. This insertion appears
to be effected by the intervention of the hyaloid
membrane, to which this fan is attached. I
have not had time to establish this con-
nexion to my satisfaction, and I still entertain
doubts respecting it. I have seen a red artery
accompany this feather-like production and run
to the crystalline. It would be very convenient
for physiology that this folded membrane
should prove muscular ; we should then have
the organ sought after, which would retract the
crystalline to the bottom of the eye." In the
Elementa Physiologiae, t. v. p. 390, he says it
originates from the entrance of the optic nerve,
but that you may remove the retina and leave
the pecten. He says again, " it advances for-
ward to the posterior part of the capsule, to
which it sometimes adheres by a thread, and
sometimes the lens is merely drawn toward it."
An artery and vein is supplied to each fold,
and perhaps to the capsule of the lens. In
the Opera Minora he says that there are two
red vessels to each fold in the kite, and no cord
runs to the lens ; that in the heron a branch of
artery runs to each fold, and it adheres so
closely to the lens that it cannot be ascertained
whether a red vessel runs from it to the lens
or not; that in the duck it is contracted toward
the lens, and adheres to it by a thread contain-
ing a red vessel. He also says that in the
wild duck it arises from the margin of the
linea alba, which terminates the entrance of
the optic nerve, contains numerous vessels,
and adheres to the lens ; and in the pie it is
large and adheres to the lens, so as to pull it.
D. W. Sommerring says, that in the pecten
of the golden eagle, of which jig. 128 is
a representation, there are fourteen folds like
ciliary processes, and that it adheres by a
transparent filament to the capsule of the lens ;
that in the great horned owl it is short and
thick, with eight folds, and adhering to the lens
by an hyaloid filament, although at a great
distance from it; and that in the macaw it is
longer than broad, has seven folds, and adheres
to the lens. In the ostrich he says it is shaped
like a patella at its base, which is white, oval,
and thick; eight lines long and five broad,
distinctly separate from the choroid, above
which it rises, the retina being interposed.
From the longer diameter of this patella (or
base) a white plane or lamina projects even up
to the lens, and sends out on each side seven
small plaits, the lower ones partly double, the
upper ones simple, black, and delicate. This
conical body, something like a black purse,
tapers toward the lens, and by its apex is
attached to the capsule by a short semi-pellucid
ligament. The white substance of the base
and partition of the pecten should not be con-
founded with the medullary part of the optic
nerve, which, emerging on all sides from be-
neath the base, expands into a great, ample,
and tender retina, terminating behind the
ciliary processes with a defined margin. Cuvier,
in his Lectures on Comparative Anatomy, says,
« It appears of the same nature as the choroid,
although it has no connexion with it ; it is like-

wise very delicate, very vascular, and imbued
with black pigment. Its vessels are derived
from a particular branch of the ophthalmic
artery, different from two which belong to the
choroid ; they descend on the folds of the
black membrane and form ramifications there
of great beauty when injected. This mem-
brane penetrates directly into the vitreous
humour, as if a wedge had been driven into
it ; it is in a vertical plane directed obliquely
forward. The angle nearest the cornea in those
species in which it is very broad, and all its
anterior margin in those in which it is narrow,
comes nearly to the inferior boundary of the
capsule of the crystalline. In some species it
approaches so near that it is difficult to say
whether or not it is attached to it ; such is the
case in the swan, the heron, the turkey, &c.
according to Petit ; but there are other birds
in which it remains at some distance, and in
which it does not appear to attach itself except
to some of the numerous plates which divide
the vitreous humour into cells. In the swan,
heron, and turkey, this membrane is broader
in the direction parallel to the produced extre-
mity of the optic nerve than in the contrary
direction. In the ostrich, cassowary, and owl
the reverse is observed. It is folded like a
sleeve in a direction perpendicular to the caudal
termination of the optic nerve. The folds are
rounded in most species ; in the ostrich and
cassowary they are compressed and sharp, and
so high perpendicular to the plane of the
membrane that at first sight it resembles a
black purse. The folds vary in number, there
being sixteen in the swan, ten or twelve in the
duck and vulture, fifteen in the ostrich, and
seven in the grand duke or great horned owl.

The purpose for which the pecten exists in
the eyes of birds does not appear to be fully
ascertained. Petit says, " when a bird views
an object with both eyes, the rays enter oblique-
ly in consequence of the situation of the cornea
and crystalline lens, and proceed to the bottom
of the eye ; but as they enter in lines parallel
to the membrane, they do not encounter it.
The rays which enter the eye in lines perpen-
dicular to the plane of the cornea encounter
this membrane, and are absorbed by it as well
as those which come from the posterior side ;
the subject is, however, a difficult one." Haller
supposed that it was merely destined to afford
a medium through which vessels might pass to
carry blood to the crystalline. Cuvier says,
" It is difficult to assign the real use of this
membrane. Its position should cause part of
the rays which come from objects at the side
of the bird to fall upon it. Petit believed
that it was destined to absorb these rays and
prevent their disturbing distinct vision of objects
placed in front. Others thought, and the
opinion has been lately reiterated by Home,
that it possesses muscular power, and that its
use is to approach the lens to the retina when
the bird wishes to see distant objects. Never-
theless, muscular fibre cannot be detected in
it, and the experiments intended to prove its
muscularity after death are not absolutely con-
clusive ; moreover, as it is attached to the side

EYE.

205

of the crystalline, it could move it only
obliquely." The experiments and inferences
contained in Sir E. Home's paper in the Phi-
losophical Transactions for 1796, do not appear
to me worthy of any attention. A pecten in
an imperfect or rudimentary state appears to
exist in fishes and reptiles, and has been noticed
by Haller, W. Sommerring, and Dr. Knox.
In the article AVES of this work Mr. Oweo
has also described the pecten, and to that arti-
cle I refer the reader for additional information.

Of the choroid gland or choroid muscle. —
The eyes of fishes present several remarkable
peculiarities, to be accounted for perhaps from
their occasional residence in the obscurity of
the deep, and at other times near the surface,
exposed to the full blaze of sunshine; they
must also be frequently exposed to great pres-
sure at considerable depths. The sclerotic is
not merely a fibrous membrane, but is strength-
ened by a cartilaginous cup, and sometimes
even by one composed of bone ; the cornea is
generally flat or presenting little of lenticular
character; the crystalline lens is spherical, and
so dense that its "central part is a hard solid;
and the choroid presents the remarkable pecu-
liarity which I have now to describe.

On cutting through the cartilaginous sclerotic,
a fluid is found generally interposed between
this and the choroid: at least it is so in the
genus gadus, (cod, haddock, &c.) The external
part of the choroid is formed by a most beau-
tiful membrane of a brilliant silver aspect,
scarcely to be distinguished from that metal
when rough and recently cleaned. On tearing
this membrane away, the vascular choroid is
exposed, and a red horse-shoe-shaped promi-
nent mass, encircling the entrance of the optic
nerve, appears. This is the choroid gland or
choroid muscle. The veins of the choroid,
apparently commencing from the iris, ascend
in tortuous inosculating branches, of enormous
size compared with the dimensions of the part,
and appear to terminate by entering this horse-
shoe-shaped organ, but this is not their distri-
bution, as it is not hollow. The area enclosed
by the organ round the optic nerve does not
exhibit the same extreme vascularity. On
pulling away a delicate film which covers the
organ, it appears composed of lamina or plates
divisible into fibres, which run transversely
from within outwards, confined into a compact
body by the delicate film just spoken of, and
a concave depression in the structure beneath.
The annexed plate, made from an accurate
drawing of a careful dissection, represents the
general form and vascularity remarkably well.

Fig. 130.

Haller, speaking of the choroid iu fishes,
says, " this organ is a fleshy pulp, composed of
short columns densely consolidated, resembling
red gelatine." Cuvier says, " its colour is com-
monly a vivid red, its substance is soft and
more glandular than muscular ; at least fibres
cannot be distinguished on it, although the
bloodvessels form more deeply coloured pa-
rallel lines on its surface. Its form is com-
monly that of a small cylinder bent like a ring
round the nerve, which ring is not, however,
complete; a segment of greater or less length is
always deficient. Sometimes, as in the Perca
labrax, it is composed of two pieces, one on
each side of the optic nerve. In other cases it
is not in a circle but an irregular curve, as in
the Salmon, Tetradon mola, and Cod ; but in
the carps and most other fishes it approaches to
to a circle. Those who suppose that the eye
changes its figure according to the distance of
objects, think that this muscle is destined to
produce this effect by contracting the choroid ;
but it appears to me that the numerous vessels
passing out of it should rather lead to its being
considered a gland destined to secrete some of
the humours of the eye. These vessels are white,
fine, very tortuous, and appear to traverse the
tunica Ruyschiana; they are well seen in the Te-
tradon mola and Perca labrax. In the Cod they
are very large, anastomose together, and are
covered by a white and opaque mucus. This
gland does not exist in the cartilaginous fishes,
as the Rays and Sharks, in which it approaches
more to the character of the eye iu the Mam-
malia, as has already been observed in speak-
ing of the tapetum and ciliary processes." D.
W. Summering says, " Around the insertion of
the nerve is seen a peculiar red, thick, soft
body of a horse-shoe shape, respecting which
it is doubted whether it be muscular, glandular,
or merely vascular. It is undoubtedly ex-
tremely vascular, and contains many large,
branching, inosculating vessels, forming a
proper membrane gradually becoming thin,
and terminating at the iris. This vascular
membrane constitutes the second or middle
layer of the choroid." This description applies
to the eye of the Cod. Sir E. Home, in a
Croonian lecture published in the Philoso-
phical Transactions for 1796, says that Mr.
Hunter considered the organ in question to
be muscular, and proceeds to state that " this
muscle has a tendinous centre round the optic
nerve, at which part it is attached to the scle-
rotic coat; the muscular fibres are short, and
go off from the central tendon in all directions:
the shape of the muscle is nearly that of a
horse-shoe; anteriorly it is attached to the
choroid coat, and by means of that to the
sclerotic. Its action tends evidently to bring
the retina forwards ; and in general the optic
nerve in fishes makes a bend where it enters
the eye, to admit of this motion without the
nerve being stretched. In those fishes that
have the sclerotic coat completely covered
with bone, the whole adjustment to great dis-
tances must be produced by the action of the
choroid muscle; but in the others, which are
by far the greater number, this effect will be

206

EYE.

much assisted by the action of the straight
muscles pulling the eye-ball against the socket,
and compressing the posterior part, which, as
it is the only membranous part in many fishes,
would appear to be formed so for that pur-
pose." Although it must be admitted that
these conclusions of Sir E. Home are derived
from insufficient data, and are probably incor-
rect in many particulars, yet it is not very im-
probable that the part in question may be mus-
cular, and, if so, may be instrumental in adapt-
ing the eye to distance by pushing up the
retina toward the lens. The organization of
the part is certainly not merely vascular, as
stated by Cuvier, and undoubtedly bears a
stronger resemblance to muscular than any
other structure; it also retains the peculiar
colour of red muscle after all the rest of the
eye has been blanched by continued macera-
tion in water. I think, however, Sir E. Home
goes too far when he describes a central tendon
without reservation.

For further information on the subject of
this article, see VISION, and VISION, ORGAN
OF.

BIBLIOGRAPHY. — In pursuit of information re-
specting the anatomy of the eye, the student need
scarcely go farther back than Zinn's work, or the
article on the same subject in Haller's Elementa
Physiologiae. The older anatomical writers were,
generally speaking, uninformed on the subject.
Ruysch's works contain some observations worthy
of attention at the time he wrote, but now scarcely
worth recording ; especially as he was a vain man,
and wrote for present fame and character rather
than truth. In Albinus's Annotationes Academicee
a few facts are recorded, upon the accuracy of
which the student may place reliance, as he was
an anatomist. Morgagni also added to the existing
information of the period at which he wrote, but
has left little more than notes or cursory remarks.
Petit's papers in the Memoires de I Academic
Royale des Sciences contain much original and
valuable matter. In this earlier period the con-
tributions of Nuck, Hovius, Briggs, and Leeuwen-
hoek should not be overlooked. Cotemporary with
or immediately following Haller and Zinn, Porter-
field, Le Cat, Lieutaud, the second Monro, Blu-
menbach, Sommerring, and many others made
valuable additions to our information on this subject.
The annexed list contains the titles of those works
which I have consulted ; some of the more modern
German monographs I have been obliged to quote
or consult from those who copied from them,
having endeavoured in vain to procure them : such
are those of Db'llenger, Chelius, Huschke, Jacob-
son, Kieser, Weber, and some others.

Nuck, Lialographia et ductuum aquosorura ana-
tome nova, Lugd. Bat. 1695. Warner Chrouet,
De tribns humoribus oculi, 1691 . Hovius, De circu-
lari humorum motu in oculis, Ludg. Bat. 1716.
Briggs, Ophthalmographia, Lugd. Bat. 1686.
Leuwenhoek, Arcana naturae detecta, Delphis, 1695 ;
or in the Philosophical Transactions, or in the
translation of his select works by Hoole, Lond.
1816. Ruyschii Thesaurus, Amstel. 1729. Al-
binus, Annotationes academics. Morgagni, Ad-
versaria anatomica, Ludg. Bat. 1723, and Epistolas,
Venetiis, 1750. Haller, Elementa physiologic
corporis humani, torn. v. Lausanne, 1763 ; also
in Opera minora, and Formation du coeur dans le
poulet. Zinn, Descriptio anatomira ocu'i humani,
Gottiug. 1780, and also in Comme.ntarii Societatis
Regiae Scientiartim Gottina;enses, t. iv. 1754. Petit,
in Memoires de 1'Academie Royale des Sciences,
1723, 25, 26, &c. Winslow, Mem. de 1'Acad.

1721. Moeller, Observationes circa retinam, in
Hallcri Disputationes anatomicae select, t. vii.
Camper, De quibusdam oculi partibus, in Halleri
Disp. anat. Lobe, De oculo humano, in same.
Wintringham, On animal structure, London, 1740.
LeCat, Traite des Sens, Rouen, 1740. Bertrandi,
Dissertatio de oculo, in Opere anatomische e
cerusiche. Porterfield, On the eye, Edinburgh, 1759.
Lieutaud, Essais anatomiques, Paris, 1766. Dud-
dell, Treatise on the diseases of the horny coat in
the eye, Lond. 1729. Descemet, An sola lens
crystallina cataractae sedes, Paris, 1758. Demours,
Lettre a M. Petit, Paris, 1767. Brendel, De fabrica
oculi in foetibus abortivis, Got. 1752. Blumenbach,
De oculis Ieuco3thiopum et iridis motu, Gott. 1786.
Wachendorf, Commercium litterarinm, 1744. Fon-
tana, Traite sur le venin de la vipere, Florence,
1781. Walther, J. G. Epistola anat. ad Wilhelm
Hunter, Berolin, 1758. Sommering, Abbildungendes
menschlichen Auges, or Icones oculi humani ; or
translated into French by Demours. Sommering, also
in Commentarii Soc. Reg. Gotting. Monro, On the
brain, the eye, and the ear, Edin. 1797. Camparetti,
Observationes dioptricae et anatomicae de coloribus,
visu et oculo, Patavii, 1798. Sattig, Lentia crys-
tallinae structura fibrosa, Halae, 1794. Mauchart,
De cornea, in Haller's Disputationes chirurgicae,
or in. Reuss Dissertationes Tubingenses. Dr.
Young, in the Philosophical Tansactions, 1793 et
seq. Home, in several papers in the Philosophical
Tiansactions, see Index. Reil, De structura ner-
vorum, Halae, 1796. Rosenthal, De oculi quibus-
dam partibus, 1801. Angely, De oculo organisque
lachrymalibus, Erlang. 1803 ; or, again, Schreger
vergleichenden Anatomie des Auges, Leipzig, 1810.
Baerens, Systematis lentis crystallina monographia,
Tubingae, 1819, and in Radius Scriptores oph-
thalmologici minores. Clemens, Tunicae corneae et
humoris aquei monographia, Gott. 1816, and in
Radius, S. O. M. Sachs, Historia duorum leu-
coethiopum, Solisbaci, 1812. Maunoir, Sur 1'or-
ganisation de 1'iris, Paris, 1812. Ribes, in Me-
moires de la Societe Med. d'Emulation, an 8ieme,
Paris, 1817. Chelius, Ueber die durchsichtige
Hornhaut des auges, Carlsruhe, 1818. Voit, Oculi
humani anatomia et pathologia, Norimbergae, 1810.
Hegar, De oculi partibus quibusdam, Gott. 1818.
Cuvier, Le9ons d'anat. comp. Bell's Anatomy.
Meckel's Handbuch d. menschl. anatomic, or the
French translation. Sommering, D.W. De oculorum
hominis animaliumque sectione horizontale, Gott.

1818. Knox, Comparative anatomy of the eye,
Trans. Royal Society of Edinburgh, 1823. Cloquet,
J. Sur la .membrane pupillaire, Paris, 1818.
«7ac0&so»,Supplementa ad ophthalmiatriam.Havniae,
1821. D'ollenger, Illustratio ichnographica oculi,
Werceburg, 1817. Weber, De motu iridis, Lipsiae,
1828. Jacob, in Philosophical Transactions, 1819.
Martegiani, Novae Observationes de oculo human.,
Napoli, 1812. Sawrey, An account of a newly -
discovered membrane in the human eye, Lond.
1807. Husche, Commentatio de pectinis in oculo
avium potestate, Jenae, 1827. Schneider, Das ende
der nervenhaut in menslichen auges, Munchen,
1827. Kieser, De anamorphosi oculi, Gott. 1804.
Jacob, in Medico-Chirurgical Transactions, vol. xii.
Lond. 1823. F. A, ab Amman, De genesi et usu
maculae lutrae, Vinariae, 1830. Dieterich, F. C.
Uber die verwundengen des linsensystems, Tubing.
1824. D'ollenger, Ubor das Strahlenblaitchen im
menschlichen auges in Acta Ph. Med. Acad. Caesar-
Leop. Car. nat. cur. t. ix. Horrebow, M. Tractatus
de oculo humano, Havniae, 1792. Jacob Imans,
Dissertatio inaug. de oculo, Lugd. Bat. 1820.
Lieblien, V. Bemerkungen iibcr das system der
krystalliense bei Saugthieren und. vogeln. Wurz-
burg, 1821. Mutter , F. Anatomische und physio-
logist-he darstellung des menschlichen auges, Wien.

1819. J. M'uller, Zur vergliechendcu physiologic
des gesichtssines des menschen und der Thiere,
Leipsig, 1826. G. R. Treviranus, Beitrage znr
anatomic und physiologie der Sinneswerkezeuge des

FACE.

207

Mcnschen und dcr Thiere, 1 Heft. Bremen, 1828.
Wardrop's Morbid anatomy of the eye. Dalrymple's
Anatomy of the eye, Lond. 1834. Mackenzie, On
diseases of the eye, Lond. 1834. Lloyd, On light
and vision, Lond. 1831. Riot, Precis elementaire
de physique, Paris, 1824. Langenbeck, B. C. R.
De retina, Gott. 1836. Berzelius, Traite de chimie,
Paris, 1833. Ammon, Zeitschrift fur die oph-
thalmologie. Radius, Scriptores ophthalmologici
minores. Reils, Archiv. fur die physiologic.
Meckel's Archiv. F, Arnold, Untersuchungen iiber
das auge des menschen, Heidelberg, 1832. Giralde,
Sur 1'organization de 1'oeil, Paris, 1836. For the
latest observations on the retina, see Ehrenberg,
Eeobachtung iiber Structur des Seelenorgans, Ber-
lin, 1836.

For the comparative anatomy of the eye, which
is still imperfect, I refer the student to the paper
of Zinn in the Gottingen Commentaries, as above
quoted ; Bidloo, De oculis et visu ; the article on
the eye in Mailer's Elemcnta Physiologiae ; Cam-

sinnes ; and, above all, to D. W. Sommering's
book. For perfect systematic treatises on the
anatomy of the eye, the student is referred to
/inn's well-known and highly valuable work,
Arnold's work just quoted, *nd, in English,
Mr. Dalrymple's treatise.

(Arthur Jacob.)

FACE (in anatomy) (Gr. ^oa-uvov ; Lat.
fades, vultus, os ; Fr. face ; Germ. Ant lit z,
Gesicht ; Ifa\.faccia). — In vertebrated animals
this term is applied to denote the anterior part
of the head, with which most of the organs
of the senses are connected ; while the cranium
is destined to contain and protect the encephalic
organs, the face is the seat of the organs cf
sight, smell, and taste, and in some animals
of a special organ of touch. The relative
sizes of cranium and face depend, therefore,
in a great measure on the relative development
of those important organs which belong to
each. For the characters of the face in the
different classes of animals, we refer to the
articles devoted to the anatomy of them, and
to the article OSSEOUS SYSTEM.

FACE (in human anatomy). The face is
situated before and below the cranium, which
bounds it above ; on the sides, it is limited by
the zygomatic arches, behind by the ears and
the depression which corresponds to the upper
region of the pharynx, and below by the base
of the lower jaw and the chin. The disposition
of the face is symmetrical ; its anterior surface
is trapezoidal, the largest side being above ;
and its vertical section is triangular. It pre-
sents an assemblage of organs which serve dif-
ferent purposes, and which by their configura-
tion and proportions constitute what are called
the features ; individually the face presents
many varieties, not only in the form and degree
of development of its several parts, as the nose,
mouth, &c., but also in the condition of its
bones, muscles, skin, and adipose tissue. The
varieties of form presented by the face afford
some of the most distinctive characters of the
different races of mankind. It differs also ac-
cording to the age and sex of the individual ;
in the infant, the peculiarities depend princi-
pally upon the disposition of the bones, and in
particular on the absence of the teeth ; but the

soft parts have also their distinctions at this
age, for while the fat is abundant, the muscles
are but little developed, and hence the slightly
marked features and the plump cheeks of
infancy.

In old age, again, the aspect of the face is
the reverse of this, for not only do its thinness
and the predominance of the muscles throw
out the features, but the skin is covered with
folds and wrinkles, from its own relaxation
and the absence of fat, aided perhaps by the
action of the muscles. The loss of the teeth,
moreover, allows the lower jaw (when the
mouth is closed) to be thrown in front of the
upper, and thus the length of the face is dimi-
nished, and a peculiar expression is imparted
to the countenance.

In women, (from the delicacy of the features
and the abundance of the cellular tissue,) the
face preserves the roundness of form, and
something of the characteristics of childhood.

BONES OF THE FACE. — The bones of the
face comprise all those of the skull which do
not contribute to form the cavity for the brain ;
they inclose, either by themselves or in con-
junction with the adjacent bones of the cranium,
1. the organs of three senses, viz. sight,
smelling, and taste ; 2. the organs of mastica-
tion and the orifices of the respiratory and
digestive canals ; 3. they give attachment to
most of the muscles of expression.

The face is divided into the upper or the
fixed, and the lower or the moveable jaw,
both of which are provided with teeth. The
lower jaw is a single and symmetrical bone ;
the upper jaw, though formed of thirteen
bones, consists principally of two, viz. the
ossa maxillaria superiora, to which the others
may be considered as additions, being attached
to them immoveably, and forming altogether
one large, irregular, and symmetrical piece,
which constitutes the upper jaw.

Of the fourteen bones which contribute to
the face, two only are single or median ; the
others are double, and form six pairs, viz.
2 ossa maxilla superioris ; 2 ossa pulati ;
2 ossa nasi ; 2 ossa mala ; 2 ossa lachrt/malia ;
2 ossa turbinata inferiora. The two single
bones are, the vomer and the os maxilla in-
serioris.

The superior maxillary bones, (ossa maxil-
laria superiora ; Germ, die Obern Kinnbacken-
beine oder Oberkiefer.) These bones, situated
in the middle and front of the face, are of
a very irregular figure ; they are united below
along the median line, and form together, the
greater part of the upper jaw. Each has four
surfaces, viz. 1. a facial or anterior; 2. a
posterior or zygomatic ; 3. an internal or naso-
palatine; 4. a superior or orbitar. The borders
are three; 1. an anterior or naso-m axillary ;
2. a posterior or pterygoid; 3. an inferior or
alveolar.

The facial surface presents from before
backwards, 1. the fossa myrtiformis, a depres-
sion situated above the incisor teeth, which
gives attachment to the depressor labii superi-
oris; 2. the canine ridge, which corresponds to
the socket of the canine tooth, and which sepa-
rates the myrtiform from, 3. the canine (or the

208

FACE.

infra-orbitar) /cMset, which gives attachment to
the levator anguli oris, and at the upper part of
which is seen the infra-orbitar foramen, giving
exit to the vessels and nerves of the same
name ; 4. the malar ridge, a semicircular crest
which descends vertically from the malar pro-
cess to the alveolar border of the bone, and
divides its facial from its zygomatic surface,
which is prominent behind, where it forms the
maxillary tuberosity, most conspicuous before
the exit of the last molar tooth, which in the
child is lodged within it. On this surface are
several small holes, (posterior dental fora-
mina,) which are the orifices of canals for the
posterior and superior dental vessels and
nerves.

From the upper and front part of the ante-
rior surface of the bone a long vertical process
(the nasal process) ascends between the nasal
and lachrymal bones to be united with the
frontal ; its external surface is rough, presenting
small irregular holes, which transmit vessels to
the cancellous interior of the bone and to the
nose, and giving attachment to the levator labii
superioris alaeque nasi muscle. The internal sur-
face of this process is marked with some minute
grooves and holes for vessels, and, tracing it
from below upwards, by a transverse ridge or
crest (the inferior turbinated ridge) for the
lower spongy bone ; above this by a depres-
sion corresponding to the middle meatus ; next
by a crest (the superior turbinated ridge)
for the upper spongy bone of the ethmoid;
and above this by a surface which receives
and completes some of the anterior ethmoid
cells. The nasal process has three borders:
1. an anterior, thin and inclined from
above downwards and forwards; above, it is
cut obliquely from the internal towards the
external surface of the bone, and below in the
contrary direction, so that this edge of the
nasal process and the corresponding border of
the nasal bone with which it is united, mutu-
ally overlap each other. 2. A poster tor border,
or surface, thick and divided into two margins
by a deep vertical groove (the lachry mo-nasal
canal) which contributes to lodge the lachrymal
sac above, and the nasal duct below. The
direction of the lachrymo-nasal canal is curved
from above downwards and outwards ; so that
its convexity looks forwards and inwards, and
its concavity in the contrary direction. The
inner margin of this groove is thin, and is
united above to the anterior border of the os
unguis, and below to the inferior spongy bone.
The outer margin is bounded and gives attach-
ment to the tendon and to some of the fibres of
the orbicularis palpebrarum ; it commonly ter-
minates below in a little tubercle (the lachrymal
tubercle). 3. The upper border of the nasal
process, which is short, thick, and irregular, is
articulated with the internal angular process of
the frontal bone.

The orbitar surface of the bone is the small-
est; it is quadrilateral, smooth, and slightly
concave, with an inclination from above down-
wards and from within outwards ; it forms the
greater part of the floor of the orbit. Along
the middle of its posterior half runs, in a direc-
tion forwards and outwards, the infra-orbitar

groove, which anteriorly becomes a complete
canal (the infra-orbitar canal), and finally
divides into an internal or larger canal, which
terminates at the infra-orbitar hole in the
canine fossa, and into an external or small
conduit, which runs in the anterior wall of the
antrum, and conveys the superior anterior den-
tal nerves to the incisor and canine teeth ; this
outer subdivision of the canal presents several
varieties in different individuals. The orbitar
surface (or plate) has four borders: 1. The
posterior, which, free and notched in the mid-
dle by the commencement of the infra-orbitar
canal, forms with the orbitar plate of the sphe-
noid and palate bones the inferior orbitar or
the spheno-maxillary fissure. 2. The internal,
which articulates from behind forwards succes-
sively with the palate, the ethmoid, and the
lachrymal bones. 3. The anterior, short and
smooth, separates the orbitar from the facial
surfaces of the bone; at its inner extremity is
the nasal process already described. 4. The
external is united to the malar bone ; on the
outer side of this border is a rough triangular
projecting surface (the malar process) which
receives the os malae, and which forms an
angle of union between the anterior, posterior,
and superior surfaces of the upper maxillary
bone.

The internal or naso-palatine surface is di-
vided along the anterior three-fourths into two
unequal parts by an horizontal plate of bone
(the palatine process) : above this is the nasal
portion forming the upper three-fourths of
this surface, and below it, is the palatine
part which forms the remaining fourth. The
palatine process forms the anterior three-
fourths of the floor of the nose, and roof of the
mouth; it presents a smooth upper surface,
concave transversely, and nearly flat in the op-
posite direction : it is broad behind and narrow
in front, where there is placed the orifice of the
anterior palatine canal, which takes a direction
downwards, forwards, and inwards, unites with
the corresponding canal in the opposite bone
at the median plane, and forms a common
canal (the canalis incisivus), which opens below
by a hole (the foramen incisivum) on the roof
of the mouth, immediately behind the middle
incisor teeth. The anterior palatine canals and
the incisive canal, which are often included to-
gether under a common name, form a tube re-
sembling the letter Y, being bifid above and
single below. The inferior surface of the pa-
latine process is rough and concave, and forms
the anterior and larger part of the roof of the
mouth ; its internal border is long and rough,
thick in front, narrow behind, and united with
the corresponding border of the opposite bone
forms the maxillary suture : this border is sur-
mounted by a half-furrow which, with that of its
fellow bone, forms a groove for the reception of
a part of the vomer. The posterior border is short
and cut obliquely at the expense of the upper
surface ; it supports the anterior margin of the
horizontal part of the palate-bone. The pala-
tine division of the internal surface of the upper
maxillary bone is narrow, and forms part of
the arched roof of the mouth ; along its junc-
tion with the palatine process is a broad shal-

FACE.

low groove for lodging the posterior palatine
nerves and vessels. The nasal portion of the
internal surface is placed above the palatine
process, and is lined on its anterior three-fourths
by the pituitary membrane. Tracing this sur-
face from before backwards we observe, 1 . the
lower aperture of the naso-lachrymal canal,
situate just behind the inferior turbinated crest
of the nasal process ; 2. posterior to this, the
orifice of the maxillary sinus, or ant rum of
Highmore, which in the sepaiated bone is a
large opening, but is contracted in the united
face by the lachrymal, the ethmoid, the palate,
and the inferior turbinated bones, which are
attached around its margin. Above this aper-
ture are seen some cells which unite with those
of the ethmoid, and its lower edge presents a
fissure in which is received the maxillary pro-
cess of the palate-bone. Below the inferior
turbinated crest, the naso-lachrymal canal and
the orifice of the antrum, the bone is concave
and smooth, and forms a part of the inferior
meatus of the nose; behind this smooth surface
and the orifice of the antrum, the bone is
rough for the attachment of the vertical plate
of the os palati, and it presents a groove, which,
descending obliquely forwards to the palatine
division of this surface, forms a part of the
posterior palatine canal.

The maxillary sinus (sinus maxillaris, antrum
Hig/tmori ; Germ, die Oberkieferhohle) oc-
cupies in the adult the whole body of the
bone : its form is triangular, with the base
directed internally towards the orifice which
has been already described, and the apex out-
wards towards the malar process. Its superior
wall is formed by the orbitar plate; the pos-
terior corresponds to the maxillary tuberosity ;
and the anterior to the canine fossa. All
these walls present ridges or crests, which
lodge canals for the passage of nerves. The
posterior and anterior walls contain the su-
perior, anterior, and posterior dental canals,
which lodge nerves of the same name. The
upper wall contains the infra-orbitar groove
and canal, which gives passage to the upper
maxillary nerve.

Borders. — 1 . The anterior or naso-maxillary
border is united above along the nasal process
to the nasal bone. Below this it is thin and
presents a deep semicircular notch, which forms
the lateral and inferior portions of the anterior
aperture of the nose. At the lower extremity
of this notch the bone projects, and forms
with its fellow of the opposite side the anterior
nasal spine. The remainder of this border
proceeds downwards and a little forwards to
terminate on the alveolar border of the bone
between the two middle incisor teeth.

2. The posterior or pterygo-palathie border,
thick, rounded, and vertical, is united below
to the palate bone, and above it forms, with
the palate bone, the anterior border of the
ptery go-maxillary fissure.

3. The inferior or alveolar border is thick
and broad, especially behind, and forms about
the fourth of an oval. It is perforated with
conical cavities (alveoli) for the reception of
the roots of eight teeth. These cavities are

VOL. n.

separated by thin transverse lamina. Tracing
them backwards from the anterior extremity
of the border, the orifices of the two first
are nearly circular, and receive the incisors ;
they are the largest, and are placed below the
nasal notch. The third, in form transversely
oval, receives the canine tooth, is of great
depth, and ascends in front of the canine fossa.
The fourth and fifth, also transversely oval,
but not so deep, receive the lesser molar
teeth; they generally present ridges in their
septa which correspond to grooves in the fangs
of the teeth which are implanted into them.

The orifices of the three last cavities are
quadrilateral, and receive the molar teeth.
The sixth and seventh are subdivided into
three lesser cavities, of which the two external
are smaller than the inner one. Sometimes
one of the molar teeth has four fangs, and
then we find its socket subdivided into a cor-
responding number of cavities. The eighth
alveolus, which receives the last molar tooth
or dens sapientiae, is not so distinctly divided
into subordinate cavities, but presents ridges
like the lesser molar. The outline of the
alveolar border is waving, convex where it
corresponds to the alveoli, and depressed op-
posite their septa. The whole of this border
is covered by the gums, and presents innu-
merable pores for the nutritious vessels. The
surfaces of the alveoli are also similarly
marked.

Connexions. — The upper maxillary articu-
lates with two bones of the cranium, viz. the
ethmoid and frontal, and sometimes with the
sphenoid by its pterygoid processes, or by an
union of the orbitar plates of both bones at
the outer extremity of the spheno-maxillary
fissure. In this case the malar bone does not
enter into the formation of this fissure. The
upper maxillary articulates with its fellow
and with all the bones of the face. The me-
dian and lateral cartilages of the nose are at-
tached to it. It receives the upper teeth, and
gives attachment to eight muscles, viz. the
orbicularis palpebrarum, the inferior oblique
of the eye, the levator labii superioris alaeque
nasi, the levator labii proprius, the depressor
alae nasi, the compressor narium, the levator
anguli oris, and the buccinator; often also
to some of the fibres of the temporal and
the external pterygoid muscles. It lodges the
naso-palatine ganglion, and gives passage to
the infra-orbitar and to the anterior and pos-
terior palatine and dental vessels and nerves.
It forms the greater part of the sides of the
nose, and of the floor of that cavity, and
of the orbit, as well as of the roof of the
mouth. It contains the maxillary sinus and the
nasal duct.

Structure. — This bone is lighter than might
be expected from its size, being occupied by the
large antrum maxillare. It is cancellous only
at the tuberosity, along the alveolar border,
and at the malar and palatine processes.

Developeinent. — The ossification of this bone
commences as early as the thirtieth or thirty-
fifth day of foetal life, near its alveolar border,
and it is complete at birth. It presents at

210

FACE.

this period, and often much later, two remark-
able fissures. 1. The incisive fissure, which
may be traced from the alveolar border be-
tween the canine and lateral incisor tooth
backwards and upwards, along the incisive
canal towards the nasal process: it is sel-
dom observable on the facial surface of the
bone. The part of the bone circumscribed by
this fissure appears to correspond to the inter-
maxillary bone of animals, and is probably
developed as a separate piece : it supports the
incisor teeth. 2. A fissure is often found ex-
tending from the infra-orbitar groove forwards
to the orifice of the canal. The existence of
these fissures has led some anatomists to sup-
pose that the bone is developed by these ossific
points.

At birth and in infancy the bone presents a
much greater proportion from before back-
wards than vertically : its nasal process is long,
its orbitar plate large, the antrum is already
distinct, the tuberosity prominent, and there
are some remarkable holes behind the incisor
teeth, which are said to have an important
connexion with the development of the second
set of teeth.

In the adult the increase in the vertical di-
mensions corresponds with the developement
of the antrum and alveolar border. In old
age the alveoli are obliterated, the border con-
tracts, and the jaw diminishes in height. In
the small vertical diameter the senile and in-
fantilft upper jaw bear a resemblance to each
other.

In the inferior mammalia, the maxillary
bones are separated anteriorly in the middle
line by a bone called os intermaxillure or
incisivum, which contains the superior incisor
teeth when they are present; sometimes this
bone is distinctly divisible into two by suture.
This bone is present, although the superior
incisors be absent, as in Ruminants and Eden-
tata, but in such cases is very small: on the
other hand, when the incisor teeth are largely
developed, it is of considerable size, as in the
Rodentia. In the mature human foatus no sign
of this bone exists, but in examining the skulls
of foetuses about the third or fourth month of
pregnancy, we observe it perfectly distinct from
the maxillary bone. It sometimes happens
that at more advanced periods, whether of in-
tra or extra-uterine life, evidence of the separa-
tion of the intermaxillary bone exists, and as
Meckel says, we often find a transverse narrow
" lacuna" on the vault of the palate, extending
from the external incisor tooth to the anterior
palatine foramen. According to Weber, how-
ever, who examined the extensive collection of
fcetal skeletons belonging to Professor Ilg in
Prague, the intermaxillary bone was distinct
only in those that had a double hare-lip. He
considers, however, that the intermaxillary bone
readily separates when the skull of a child of
one or two years old is placed for some time
in dilute muriatic acid.*

The palate bones, (ossa palatina ; Germ.

* See Weber in Froriep's Notizen, 1820, quoted
in Hildebrandt's Anatomic, B. ii. S. 95.

die Saumenbeine,) situated at the back part of
the nose and roof of the mouth, locked be-
tween the maxillary bones and pterygoid pro-
cesses of the sphenoid, consist of two thin
plates, one short and horizontal, the palatine ;
the other long and vertical, the nasal. The
palatine process, or plate, has two surfaces and
four borders. The upper surface, or the nasal,
is smooth and concave, and forms the posterior
fourth of the floor of the nose. The lower sur-
face, the palatine, rough, and slightly concave
anteriorly, has on its posterior and outer part a
transverse crest with a depression behind it for
the attachment of the circumflexus palati muscle.
In front and to the outer side of this is the
inferior orifice of the posterior palatine canal,
behind which are two or three small openings
called accessory palatine holes, and in front of
it is the commencement of the groove which
lodges the posterior palatine vessels and nerves.

The anterior border is cut obliquely from
below upwards and forwards, and rests on the
posterior border of the palatine plate of the
upper maxillary bone, forming with it the
transverse palato-maxillary suture. The pos-
terior border, thin and concave, gives attach-
ment to the soft palate.

The internal border, rough and thick, is
united to its fellow of the opposite side ;
above, it forms a grooved crest, which receives
a part of the vomer, and is continuous with a
similar crest formed on the internal border of
the palatine plate of the upper maxillary bone.
Behind, this border terminates in a sharp
point, which, in conjunction with the corres-
ponding projection of the opposite bone, forms
the posterior nasal spine, to which the levator
uvulae muscle is attached. The external border
is continuous with the vertical plate.

The nasal process, or plate, has two surfaces
and four borders. The internal or nasal pre-
sents, tracing it from below upwards, 1. a
smooth concave surface, which forms part
of the inferior meatus: 2. a horizontal crest,
the inferior turbinated crest, for the attach-
ment of the inferior turbinated bone : 3. ano-
ther concave surface forming part of the mid-
dle meatus : 4. another horizontal crest (the
superior turbinated crest), shorter than the
former, for the attachment of the middle tur-
binated bone of the ethmoid. This surface is
covered with the pituitary membrane.

The external or zygomata-maxillary surface
is rough in front, where it rests against the
upper maxillary bone ; behind this the lower
two-thirds are marked by a groove, which, in
conjunction with one on the upper maxillary
bone, forms the posterior palatine canal.
Above this, the bone is smooth, and forms the
inner and deep part of the pterygo-maxillary
fissure.

The anterior border, thin and projecting,
forms a process (the maxillary) which is re-
ceived into the fissure in the lower edge of the
orifice of the maxillary sinus.

The posterior or pterygoid border is united
to the anterior border of the pterygoid process
of the sphenoid : below, it becomes broad
and is continued along a process which stands

FACE.

211

downwards, outwards, and backwards, from
the angle of union of the posterior borders of
the vertical and horizontal plates of the bone.
This process is the pterygoid or pyramifUU, and
presents three grooves behind, viz. one internal
and one external, (of which the inner is the
deeper,) for the reception of the anterior borders
of the lower extremity of the pterygoid plates ;
and a middle triangular groove extending high
up, and which forms a part of the pterygoid fossa.
The outer surface of this process is rough,
and is articulated with the upper maxillary
bone : its apex is continuous with the external
pterygoid plate.

The inferior border is united to the horizon-
tal plate.

The superior border presents a deep semi-
circular notch (sometimes a hole), which with
the sphenoid bone above forms the spheno-
palutine foramen. This notch divides the upper
border into two processes, 1. the posterior (the
sphenoidal); 2. the anterior (the orbitar). The
sphenoidal process is curved inwards and back-
wards, and has three surfaces, 1. an internal or
nasal, forming part of the cavity of the nose;
2. an external, which forms below the spheno-
palatine foramen the deep wall of the pterygo-
maxillary fissure ; 3. an upper, which is con-
cave and rests against the body of the sphenoid
bone, and contributes to the pterygo-palatine
canal.

The orbitar process stands upwards and
outwards on a narrow neck, and presents five
surfaces. 1. The anterior (or maxillary) arti-
culates with the upper maxillary bone. 2. The
internal (or ethmoidal) forms a cell which unites
with those of the ethmoid. 3. A posterior
(or sphenoidal) presents a cell uniting with the
sphenoid, and communicating with its sinuses.
4. The superior (or orbitar), which is smooth
and contributes to form the floor of the orbit :
its posterior border forms a part of the spheno-
maxillary fissure, and separates the orbitar sur-
face from, 5. the external or zjgomatic, which
looks into the pterygo-maxillary fissure.

Connexions. — Each palate bone articulates
with five bones, viz. two of the cranium, the
sphenoid and the ethmoid ; and with three of
the face, the upper maxillary, the inferior turbi-
nated, and the vomer, besides its fellow bone of
the opposite side. It is lined with the buccal
and pituitary membrane. It contributes to form
the cavities of the mouth, nose, and orbit ; the
pterygo-maxillary fissure, and the zygomatic and
pterygoid fossae. It gives attachment to the
soft palate, and passage to the spheno-palatine,
pterygo-palatine, and posterior palatine vessels
and nerves ; also to the two pterygoid muscles,
the circumflexus palati, the levalor uvulae, the
palato-glossus, and the palato-pharyngeus.

The structure is compact, except at its pte-
rygoid process, where it is cancellous.

Developement. — It is complete at birth, ex-
cept that the vertical plate is short to corre-
spond with the short vertical diameter of the
upper maxillary. About the third month
ossification appears in a single point, at the
junction of the two plates with the pyramidal
process.

Jllalar bones (ossa rnalee v. malaria v. zygi^
matica ; Fr. os de la pommette ; Germ, die
Jochbeine oder Backenbetne). — These bones,
corresponding in situation to the prominence of
the cheeks, are somewhat of a quadrilateral
figure. Each presents three surfaces; 1. an
external or facial; 2. an internal or temporo-
zygomatic; 3. a superior or orbitar. There
are besides four borders and four angles.

The facial surface forms the eminence of the
cheek, looks outwards and forwards, is smooth
and slightly convex in front, and is marked by
one or more small holes f malar foramina),
which give passage to vessels and nerves. It is
covered above by the integuments and the orbi-
cularis palpebrarum, and below and externally
it gives attachment to the zygomatic muscles.

The temporo-zygomatic surface is smooth
and concave below ; and internally there is a
rough surface which rests on the malar process
of the upper maxillary : about the centre or to-
wards the upper part of this surface is observed
the internal orifice of a malar canal or a malar
hole. The temporal muscle is attached to this
surface.

The orbitar surface is smooth, concave, and
is formed upon a plate of bone (the orbitar
process), which stands inwards, and contributes
to the outer wall and floor of the orbit : its op-
posite surface above makes part of the tempo-
ral fossa. On the orbitar surface we observe
the orifice of a malar canal. The orbitar pro-
cess has an irregular summit, which receives
the frontal bone ; below, it is articulated with
the outer border of the orbitar plate of the
sphenoid ; in the middle it corresponds to the
extremity of the spheno-maxillary fissure ; and
inferiorly it is united to the outer border of the
orbitar plate of the upper maxillary bone.

Of the four borders two are anterior and two
posterior. The anterior superior, or the orbi-
tar, is smooth, concave, and forms the outer
and lower third of the base of the orbit. The
anterior inferior, or the maxillary, rests upon
the malar process of the upper maxilla from its
extremity to the inferior orbitar foramen. The
posterior superior, or temporal border, is waved
like the letter S, and gives attachment to the
temporal fascia. The posterior inferior, or
masseteric border, is thick, and gives attach-
ment to a muscle of the same name. The four
angles are, 1. thick, rough, superior or frontal,
which receives the external angular process of
the frontal bone; 2. the interior or orbitar,
which is pointed ; and, 3. the inferior or malar,
which is round, and forms the extremities of
the maxillary border, and which rests on the
malar process of that bone. The posterior or
zygomatic is cut obliquely from above down-
wards and backwards, and supports the zygo-
matic process of the temporal bone.

Connexions. — The malar is connected with
and locked between four bones, viz. the frontal,
the sphenoid, the upper maxillary, and the
temporal. It contributes to form the orbit, the
temporal, and the zygomatic fossse. It gives
attachment to four muscles, viz. the temporal,
the masseter, and the two zygomatic ; and it
gives passage to malar vessels and nerves.

P2

212

FACE.

The structure is compact, except near its
upper and lower angles, where there is some
cancellous tissue.

Developement. — Its ossification commences
in one piece about the fiftieth day, and is com-
pleted at birth, when the bone appears thicker,
and its orbitar plate larger in proportion than
in the adult : its vertical diameter is, however,
narrow, and the malar holes are large.

The nasal bones (ossa nasi ; Germ, die
Nasenbeine) form the upper part of the
nose, and are placed between the nasal pro-
cesses of the upper maxillary and below the
frontal bones, inclining from above downwards
and forwards. They have two surfaces, and
their form is quadrilateral, the vertical exceed-
ing the transverse diameter. They are stout
and narrow above, and thin and broader below.
The anterior or cutaneous surface is smooth,
covered by the integuments and pyramidalis
muscle, concave from above downwards, con-
vex transversely. An oblique hole for the
passage of vessels is usually found above the
centre of one or both nasal bones, and some
smaller foramina are scattered over the surface.
The posterior or pituitary surface is concave,
narrow, especially above, and lined by the
olfactory membrane, presenting grooves for
vessels and the internal orifice of the canal (or
hole) mentioned above.

The borders are four : a superior, short,
thick, dentated, inclined from above down-
wards and backwards, and resting on the nasal
notch of the frontal bone between its two in-
ternal angular processes : the inferior border,
longer than the preceding, thin, jagged, in-
clining from the median line downwards and
outwards, and generally presenting about its
centre a slight notch for the passage for a fila-
ment of the nasal nerve. This border forms
the upper and front part of the anterior opening
of the nasal fossae, and gives attachment to the
lateral cartilages of the nose. The external
border is the longest, and is cut obliquely for
its articulation with the nasal process of the
upper maxillary bone. The internal border is
shorter, thick and rough above, and thin be-
low : it forms, on the inner aspect of the bone,
in conjunction with the corresponding part of
the bone of the opposite side, a ridge and
groove for the reception of the nasal process or
spine of the frontal bone, and for the upper and
anterior border of the perpendicular plate of
the ethmoid.

Connexions. — The nasal bones articulate
with each other, with the frontal, ethmoid, and
upper maxillary bones, and with the lateral
cartilages of the nose : they form a part of the
cavity of the nose.

Their structure is cancellous and thick above,
thin and compact below.

Developement. — They are perfectly ossified
at birth, when they are proportionally longer
than in the adult, corresponding in this respect
with the depth of the orbit and the smallness of
the anterior aperture of the nose. The ossifica-
tion of each nasal bone commences by a single
point about the beginning of the third month.
The lachrymal bones (ossa unguis v. lachry-

malia ; Germ, die Thr'dnenbeine) are qua-
drilateral in form, thin, semitransparent, and
are situated on the anterior part of the inner
wall of the orbit between the ethmoid, frontal,
and upper maxillary bones ; they derive one
of their names from the resemblance which
they bear to a finger-nail. Each bone presents
two surfaces and four borders.

The external or orbitar surface is divided at
its anterior third by a vertical crest, terminating
below in a little curved process which forms
the outer wall of the upper orifice of the nasal
canal ; in front of this crest the bone is per-
forated with numerous little holes, and its sur-
face is concave and forms with that of the
nasal process of the upper maxilla the canal
for the lachrymal sac. The posterior part of
this surface is smooth, nearly flat, and is
continuous with that of the os planum of the
ethmoid, which lies immediately behind it.

The internal or ethmoidal surface is rough,
and is divided by a vertical groove, which
corresponds to the crest on the orbitar aspect
of the bone; the anterior division is convex
and forms part of the middle meatus; the pos-
terior division is in contact with the ethmoid
and contributes to close its cells.

Of the four borders, the superior is the
shortest and thickest ; it is irregular and arti-
culates with the inner border of the orbitar
plate of the os frontis. The inferior is divided
into two parts by the lower extremity of the
crest already described on the anterior surface
of the bone ; in front of this the border de-
scends along a thin process or angle of the
bone, which is articulated with the inferior
turbinated bone, and contributes to form the
inner wall of the canal for the nasal duct ;
behind, this border is broad, and rests on the
inner margin of the orbitar plate of the upper
maxillary bone. The anterior border is slightly
grooved for the reception of the inner margin
of the posterior border of the nasal process
belonging to the upper maxilla. The posterior
border is thin and articulates with the anterior
edge of the os planum. The os unguis has
four angles, of which the anterior inferior is
remarkable for its length.

Connexions. — This bone articulates with the
frontal, the upper maxillary, the ethmoid, and
the inferior turbinated ; it contributes to form
part of the orbit of the cavity of the nose and
of the groove for the lachrymo-nasal duct.
It gives attachment to the reflected portion of
the tendon of the orbicularis palpebrarum,
and to the tendon of the tensor tarsi muscles.
In structure it is thin and compact.
Development. — It is complete at birth, ex-
cept at its posterior superior angle, where there
is a deficiency between it and the frontal and
ethmoid bones, and where a separate piece is
sometimes formed. It is broader from back
to front in proportion, at this period of life,
than in the adult, and its lachrymal groove is
larger. Its ossification commences by a single
point between the third and sixth months.

A small lachrymal bone has been described
as sometimes found at the lower part of the
os unguis; and not unfrequently some separate

FACE.

2.13

pieces are found at its angles, formed either
from the ethmoid or from the orbitar plate of
the upper maxillary bone.

The inferior turbinuted bones, (oss&spongiosa
v. turbinata injima; Germ, die untern Muscliel-
beine) of an oval form, thin and spongy in their
appearance, are placed horizontally along the
lower part of the outer wall of the nasal cavities,
separating the middle from the inferior meatus,
and contributing to increase the surface of the
nose. Each bone presents two surfaces, two
borders, and two extremities. The internal
surface is rough, convex, and looks towards the
septum of the nose, which it sometimes touches
on one side when that partition inclines more
than usually to the right or left. The external
surface is concave, exhibiting many small
fossae or pits ; it looks towards the upper
maxilla and forms a part of the inferior meatus.
Both surfaces are very irregular or spongy and
are pitted by vessels, but especially by veins,
which ramify abundantly upon them. The
inferior border is convex and thick, particu-
larly at its centre, where it descends towards
the floor of the nose. The upper border is
thin and irregular, and presents from before
backwards, 1 . a thin edge, which is attached
to the inferior turbinated crest on the nasal
process of the upper maxilla; 2. a process
(the lachrymal) which ascends towards the
curved process of the os unguis, with which and
with the adjacent part of the upper jaw-bone it
unites to complete the canal for the nasal duct;
3. some irregular projections (ethmoidal pro-
cesses) which ascend and unite with the
ethmoid ; 4. a thin, curled, dog's-ear-looking
process (the auricular or maxillary), which,
descending and overhanging the internal sur-
face of the bone, is attached to the lower part
of the opening of the antrum, which it con-
tributes to circumscribe; 5. an edge which is
articulated with the inferior turbinated crest
of the palate-bone. The orifice of the antrura
is situated just above the centre of this border,
and opens consequently into the middle mea-
tus.

The extremities or angles are formed by the
union of the two borders ; the posttrior extre-
mity is more pointed than the anterior.

Connexions. — Each inferior turbinated is
united with four other bone>, viz. the upper
maxillary, the lachrymal, the ethmoid, and the
palate. It is covered with the pituitary mem-
brane ; it contributes to enlarge the surface of
the nasal cavity, and to form a part of the
nasal canal and middle and lower meatus.

Its structure is compact.

Its development commences at the fifth month
by a single point of ossification.

The vomer (Germ, das PJlugscharbein ) is
of a quadrilateral figure, and resembles a
ploughshare ; it is a single and symmetrical
bone, situated in the median plane, and forming
the posterior and inferior part of the septum
nasi. It has two lateral surfaces and four
borders. The surfaces, which are right and
left, are smooth, flat, and lined by the pitui-
tary membrane; sometimes, when the bone
inclines much to either side of the nose,

one of these surfaces is convex and the other
concave ; they present an oblique groove or
grooves for the naso-palatine nerves and
vessels.

The superior border (or surface) is broad,
and may be termed the base of the bone ; it
presents a deep groove in the middle, which
receives the rostrum of the sphenoid, and on
each side of this are two plates or laminae
(sometimes called the alae) which are received
into fissures of the sphenoid on each side
of the rostrum, and which contribute to form a
longitudinal canal for the ethmoidal vessels.

The anterior border is oblique from above
downwards and forwards ; above it presents a
deep groove, which is a continuation of that
on the upper border, and which receives the
perpendicular plate of the ethmoid: below,
this border is nearly flat, where it is united to
the middle cartilage of the nose.

The inferior border is the longest, and is
received into the grooved crest formed by the
united palatine plates of the superior maxillary
and palate bones ; in front this border extends
as far as the anterior nasal spine.

The posterior border, thick above, thin be-
low, is oblique, slightly curved, and forms the
partition between the two posterior openings
of the nose.

Connexions. — The vomer is connected with
four bones, viz. the sphenoid and ethmoid
above, the superior maxillary and palate below :
it is covered with the pituitary membrane, and
forms, with the perpendicular plate of the
ethmoid and the middle cartilage, the septum
of the nose.

Its structure is compact, and it is formed
of two thin lateral plates, which are distinct
above, but united inferiorly.

Its development occurs by a single ossific
point about the third month, and at birth it is
completely ossified.

The os maxillare inferius (Germ, das untere.
Kinnbackenbein, oder der Unterkiefer ) . This
single bone, which alone forms the lower jaw,
occupies the lower and lateral parts of the face ;
it is a flat, symmetrical bone, and bears some
resemblance in shape to a horse-shoe. It con-
sists of a middle or horizontal portion (the body),
and of two lateral ascending branches (the rami),
which are connected with the body nearly at
right angles.

The body is curved, nearly horizontal, in-
clining from before backwards, and a little
upwards, and presents two surfaces and two
borders.

The anterior surface is convex, and has in
the centre a vertical line (crista mentalis ex-
terna), which marks the union of the two
halves of which the bone consists in the young
subject: this line terminates below in a tri-
angular eminence (the mental process). The
vertical direction of the lower jaw at the sym-
physis, and its curved figure anteriorly, form-
ing what is termed the chin, are both charac-
teristic of the human race. From the angles
of the mental process arises on each side the
external oblique line, faintly marked in front,
but becoming distinct as it ascends diagonally

214

FACE.

along this surface of the bone to terminate at
the anterior border of the ramus of the jaw;
it gives attachment to muscles and separates
the external surface of the bone into two parts,
viz. an anterior superior, which presents, ex-
ternal to the symphysis, 1. a depression (the
fossa mentalis) for the attachment of a muscle;
2. to the outer side of this the mental foramen,
which is directed obliquely upwards and out-
wards; it is the lower orifice of the inferior
dental canal, which conveys nerves and vessels
to the teeth of the lower jaw; 3. a number of
ridges and grooves near the alveolar border of
the jaw, which correspond to the sockets of the
teeth and to the septa which divide them :
this part of the bone is covered by the gums.
The surface below and behind the oblique line
is smooth, or only faintly marked with irre-
gular lines for the attachment of the platysma
myoides.

The internal surface of the body of the
lower jaw is concave, and presents in the
median line, at the symphysis, a vertical crest
(crista mentalis interna), which is not so
distinct as the corresponding ridge on the outer
surface of the bone : at its lower extremity is
a tubercle having four summits (the genial
processes, yeveiov, chin, spina interna,) which
give attachment to two pairs of muscles, viz.
the two superior genial processes to the genio-
hyo-glossi, the two inferior to the genio-
hyoidei : below and to the outer side of these
processes, on the lower border of the bone,
are two oval rough depressions, one on each
side of the symphysis, for the attachment of
the anterior bellies of the digastric muscles.
From the genial processes proceeds obliquely
upwards and backwards, to join the anterior
border of the ramus of the jaw, the internal
oblique line, or the mylo-hyoid ridge. It is
distinctly marked and very prominent oppo-
site the last molar tooth; like the external
oblique line it divides the bone diagonally into
two triangular portions, the anterior of which,
situated above and in front of the ridge,
is smooth, concave, and to the outer side of
the genial processes presents a depression
(sublingualfosm) for the reception of the sub-
lingual gland : elsewhere this surface is lined
by the gums, and forms the inner wall of the
alveolar cavities; but it is destitute of the
ridges and depressions which are seen on the
outer surface ot the bone. The triangular
surface below the oblique line is marked by
numerous small holes for the passage of nu-
tritious vessels, and by a large depression
(the submaxillary fossa) for the reception
of the submaxillary gland. The two oblique
maxillary lines which have been just described
divide the body of the jaw into two portions,
one superior or alveolar, the other inferior or
basilar : in the foetus the former predominates
considerably; in the adult they are nearly
equal, and in the edentulous jaw of old age
the body almost entirely consists of the basilar
portion.

The upper or alveolar border forms a lesser
curve than that of the alveolar border of the
superior maxilla : like it, however, it presents

sockets for the reception of sixteen teeth, which
vary also in form and depth in correspondence
with the fangs of the teeth which they lodge.
The orifices of the sockets, however, take a
direction different from those of the upper jaw,
for while the sockets of the upper incisors look
downwards and forwards, those of the lower
are directed upwards and backwards; and
again the alveoli of the upper canine and
molar teeth look downwards and outwards,
whereas those of the lower are directed up-
wards and inwards : hence, from this different
inclination of the teeth in the two jaws, and
from the larger curve described by the alveolar
border of the superior maxilla, we find that
when the mouth is closed the upper front teeth
cover the lower and at the sides overhang
them a little. This arrangement is favourable
to the division and mastication of the food.

The lower border or base is smooth and
thick, and forms a larger curve than the upper,
so that the surfaces of this jaw have an in-
clination from above downwards and forwards:
it forms the oval border of the lower part
of the face, and is the strongest portion of the
bone.

The rami are flat, quadrilateral processes,
which stand up from the body of the jaw at
almost a right angle: in the child and old
person this angle is much more obtuse. Each
ramus presents two surfaces and four borders.
The external or masseteric surface has an
inclination from above downwards and more
or less outwards : it is rough, especially below,
where it presents some irregular oblique ridges
and depressions for the attachment of the
masseter: in front of these marks, near the
lower border of the bone, there is often a
slight groove, which indicates the course of
the facial vessels.

The internal or pterygoid surface is also
rough below for the attachment of the internal
pterygoid muscle. In its centre is the spreading
superior orifice (superior dental foramen) of
the lower denial canal, marked and partly
hidden internally by a spine, which gives
attachment to the internal lateral ligament of
the temporo-maxillary articulation : from this
hole, taking a direction downwards and for-
wards is a groove (the mylo-hyoid groove),
which lodges the branch of the inferior dental
artery and nerve.

The borders of the rami are, an anterior
or buccal, grooved below, where it corre-
sponds with the alveolar border of the bone ;
the margins of this groove, which are con-
tinuous with the oblique lines of the bone,
unite above and form a sharp convex edge.
The posterior or parotid border is round and
thick above, and narrow below, and is em-
braced by the parotid gland : inferiorly and
internally it gives attachment to the stylo-
maxillary ligament. The superior or zygomatic
border is sharp and concave, forming a notch
(the sigmoid notch), which looks upwards.
The inferior border is rounded, and is con-
tinuous with the lower border of the body.

The angles of the lower jaw are formed
by the union of the body and rami; each

FACE.

215

is turned a little outwards, and in the adult
forms nearly a right angle ; in the infant and
in the old person it is obtuse. This part of
the bone, is prominent and separates the in-
sertion of the masseter and internal pterygoid
muscles.

On the upper part of each ram us stand
two processes, which are separated by the
sigmoid notch; the anterior is the coronoid,
which is of a triangular form, flattened laterally,
and sharp in front and behind ; its summit
is somewhat rounded : this process gives at-
tachment to the temporal muscles. The con-
dyloid process is situated behind the sigmoid
notch, and arises from the ramus by a narrow
neck, which is directed upwards and a little
inwards, swelling above into an oval head
or condyle, that has an articular surface on
its summit. This articular surface is trans-
versely oval, convex, covered in the recent
subject with cartilage, and inclines from within
outwards and a little forwards. The condyle,
from the direction of its neck, somewhat over-
hangs the internal surface of the ramus; it
is articulated with the anterior division of the
glenoid cavity of the temporal bone. The
direction and form of its articular surfaces
are calculated to facilitate the rotatory move-
ments of the lower jaw during mastication.
In front the neck of the condyle presents a
depression for the attachment of the external
pterygoid muscle.

Structure. — The lower jaw is formed of two
complete plates, united by cancellous tissue,
which is traversed by a long curved canal (the
inferior dental canal), which conveys the
vessels and nerves that supply the teeth. This
canal commences in a groove just above the
superior dental foramen, which is situated on
the internal surface of the ramus; it then
enters the substance of the bone, taking the
course of the internal oblique line below, and
parallel to which it runs as far as the second
bicuspid tooth, where it divides into two
canals, one short and wide, which terminates
on the external surface of the bone at the
inferior dental foramen ; and another smaller
one, which continues onwards as far as the
middle incisor tooth, where it ceases. From
the upper side of this dental canal small tubes
arise, which proceed to the alveoli ; they
convey vessels and nerves to the fangs of the
teeth. The situation and size of the dental
canal vary according to the age of the individual.
At birth it runs near the lower border of the
bone, and is of considerable magnitude; after the
second dentition it becomes placed just below
the mylo-hyoid ridge ; in the edentulous jaw
it runs along the alveolar border of the bone,
its size is much diminished, and the mental
foramen is found close upon the upper border
of the bone.

Connexions and uses. — The lower jaw is arti-
culated with the temporal bones, and receives
the sixteen inferior teeth. It gives attachment
to fourteen pairs of muscles, viz. the temporal,
the masseter, the two ptery golds, the bucci-
nator, the superior constrictor of the pharynx,
the depressor anguli oris, the depressor labii

inferioris, the levator menti, the platysma,
the genio-hyo-glossus, the genio-hyoideus, the
mylo-hyoideus, and the digastric. Four pairs
of ligaments are attached to it, viz. the external
and the internal lateral ligaments of the tem-
poro-maxillary articulation, the pterygo-maxil-
lary (or intermaxillary) ligament, and the stylo-
maxillary ligament. It forms the lower part
of the face and the cavity of the mouth ; it
protects the tongue, salivary gland, and pharynx ;
it differs from the upper jaw and from all the
other bones of the head in its remarkable
mobility ; and it contributes essentially to
mastication as well as to deglutition and
articulation.

Development.- — The lower jaw at birth con-
sists of two lateral halves, which are united
vertically in front along the median line by
a piece of cartilage, forming what has been
improperly called a symphysis. A few months
after birth the removal of this cartilage com-
mences, and the two halves of the bone
become united below; but not unfrequently
a fissure remains above for several months.
At this period the alveolar border is, like that
of the upper jaw, very thick, and contains
some large irregular cavities which lodge the
first set of teeth. Besides the superior dental
foramen there is found in the foetus another,
which leads to a temporary canal that supplies
the first set of teeth, and behind the alveoli
of the incisors may be observed a row of holes
which are said to be connected with the de-
velopment of the second set of teeth. Some
authors maintain that each side of the lower
jaw is developed by four separate points of
ossification ; but this assertion wants confirma-
tion. It is certain that this bone is among
those which are the most early developed, and
in the embryo of two months it is already
of considerable size. Its alveolar border is
at first a mere groove, of which the internal
margin is defective, and which gradually be-
comes hollowed into separate sockets as the
teeth are developed. The changes of form
which the lower jaw undergoes from birth till
old age depend chiefly upon the development
and decay of the teeth. Some of these changes
have been already noticed, and will be found
to correspond with those which occur in the
alveolar border of the upper maxilla ; the
varying form and direction of the rami and
angles of the lower jaw we have noticed,
and for the more detailed account of the de-
velopment of this bone as connected with
dentition, we refer to the article TEETH.

Of the face in general. — Dimensions. — The
vertical diameter of the face is the greatest,
and extends in front from the nasal eminences
of the frontal bone to the lower border of the
symphysis menti; this diameter decreases as
we trace it backwards. The transverse dia-
meter is next in length if measured at the
level of the malar bone, where it is most con-
siderable; below and above this it gradually
diminishes. The antero-posterior diameter is
greatest at the level of the cheek-bones, where it
extends from the cuneiform process of the occi-
pital bone to the anterior nasal spine of the upper

FACE.

maxilla ; this diameter also diminishes both
above and below, but more especially below,
where it comprises merely the thickness of
the mental portion of the lower jaw.

The bones which form the upper jaw are
united with those of the cranium above by a
very irregular surface; below they are on a
level with the occ-ipital foramen, and hence
that part of the face which descends below
the cranium is formed exclusively by the lower
jaw.

The area of the face, as presented by a
vertical longitudinal section of the skull, is
of a triangular figure, and forms (the lower
jaw excepted) in the European about one-
fifth of the whole area of the skull ; in the
Negro the area of the face increases in propor-
tion, and forms two-fifths of the whole.

The bones of the face form, when united,
a pyramid with four irregular surfaces or
regions, and presenting a base above, which
is connected with the cranium, an apex below
at the chin.

The anterior surface or facial region presents
many varieties of form and proportion in
different individuals, as well as others more
important, which characterise the various races of
mankind : (see the article MAN.) This region
is bounded above by the lower border of the
frontal bone, extended between its two external
angular processes : laterally it is limited by
lines drawn from these processes to the anterior
inferior angles of the malar bones : below this
it follows the curve of the malar ridge of the
upper maxilla, and it terminates at the outer
extremity of the base of the lower jaw. This
surface presents from above downwards along
the median line, the fronto-nasal suture, which
is continued laterally into the fronto-maxillary
and fronto-ethmoidal sutures, all contributing
to form the common transverse facial suture
which unites the bones of the cranium and
face. Below the fronto-nasal suture the nasal
bones, united by the nasal suture, form the
prominent arch of the nose in conjunction
with the nasal processes of the upper maxillary
bones, with which the ossa nasi articulate on
each side by the naso-maxillary suture. Below
the nasal bones is the anterior orifice of the
nasal fossae, of a pyriform shape, narrow above,
broad inferiorly, where it terminates in the
projecting anterior nasal spine : the margins
of this orifice are sharp, and are formed by
the nasal and upper maxillary bones. Below
the nasal spine is the intermaxillary suture,
which terminates on the alveolar border of the
upper jaw between the middle incisor teeth :
on each side of this suture is the myrtiform
fossa. On the lower jaw is observed, in the
median line, the mental ridge and process,
and on each side of it a depression for muscles.

The facial region presents from above down-
wards, on each side, the aperture or base
of the orbit, of a quadilateral form, and in-
clining from within outwards and a little back-
wards. The margin of this opening is formed
above by the supra-ciliary ridge of the frontal
bone, in which is observed the supra-orbitar
notch or foramen. At the outer extremity of

this ridge is the fronto-jugal suture, uniting
the external angular process of the frontal
bone with the frontal process of the malar :
below this is the prominence of the cheek
and the curved orbitar border of the malar
bone, forming the outer and lower part of
the margin of the orbit. Internal to this we
find the short orbitar border of the upper
maxillary bone, which presents at its nasal
end the groove for the lachrymal sac. Below
the inferior border of the orbit is the infra-
orbitar foramen, to the outer side of which
is the oblique jngo-maxillary suture, and
below it the canine fossa, bounded exter-
nally by the malar ridge, in front by the
canine ridge and the anterior orifice of the
nose, and below by the alveolar border of
the jaw and by the teeth. On the lower jaw
we find the teeth, the alveolar ridges and
depressions, the mental foramen, and the ex-
ternal oblique line.

The posterior or guttural surface consists
of three parts, two of which, the upper and
lower, are vertical ; the middle is horizontal.
The upper vertical portion presents along the
median line the oblique posterior border of
the vomer, which divides the posterior apertures
of the nasal fossae; above is the articulation
formed by the base of the vomer and the
sphenoid ; below is the posterior nasal spine
formed by the united palate bones. At the
sides of the vomer are the oval posterior
orifices of the nose, greatest in their vertical
diameter, and bounded superiorly by the
sphenoid and sphenoidal processes of the
palate bones, inferiorly by the palatine plates
of the same bones, internally by the vomer,
and externally by the pterygoid processes. On
the outside of these apertures are placed the
pterygoid fossae, formed by the pterygoid plates
of the sphenoid and by the pyramidal process
of the palate bone. External to these are the
large zygomatic fossae or spaces, which belong
to the lateral regions of the face.

The horizontal portion of this surface is
oval, concave, rough, and forms the roof of
the mouth, consisting of the palatine plates
of the palate and upper maxillary bones, on
which is seen a crucial suture, formed by the
longitudinal and transverse palatine sutures.
At the posterior and outer angles of this hori-
zontal portion are situated the posterior palatine
canals and the grooves which proceed from
them along the roof of the mouth ; on the
inferior surface of the palate bones are ridges
and depressions for the attachment of muscles,
while behind the middle incisor teeth is placed
the anterior palatine foramen. At the sides
and in front the palatine arch is bounded by
the alveolar border and teeth of the upper
jaw, behind which descend the pterygoid pro-
cesses of the sphenoid and palate bones.

The inferior vertical division of this region
is formed by the inner surface of the lower^jaw
and teeth ; it presents in front, along the
median line, the inner mental ridge, and the
genial processes ; external to these the internal
oblique lines, the sublingual and submaxillary
fossae, the superior dental foramen, its groove

FACE.

217

and process ; the condyles and angles of the
jaw, its alveolar border and its base, which
terminates it below, and near which, at the
chin, are seen the depressions for the .digastric
muscles.

The lateral or zygomatic surfaces on each
side are bounded above by the temporal border
of the malar bone and by the zygomatic arch ;
in front by a line extended vertically from the
external angular process of the frontal bone to
the base of the lower jaw, and behind and
below by the free border of the body and ramus
of the inferior maxilla.

This region presents a superficial and a deep
portion : the former comprises the lateral aspect
of the malar bone, the zygomatic arch, and
the external surface of the ramus of the jaw.
On it we may remark, proceeding from above
downwards, the temporal border of the malar
bone and zygoma, forming the outer boundary
of the temporal fossa; the external malar holes,
the zygoma and its suture, which unites the
malar and temporal bones ; the inferior or
masseteric border of the zygoma, the sigmoid
notch of the lower jaw and the outer surface of
its ramus, coronoid and condyloid processes
and angle. The deeper division of this region
presents the large zygomatic fossa, and is
situated internal to the ramus of the jaw, which
forms its outer boundary, and which must be
removed to expose it completely : this done,
the fossa is brought into view, bounded in
front by the posterior surface of the upper jaw
and part of the malar bone ; superiorly by the
inferior surface of the great wing of the sphe-
noid below its temporal ridge; at this part of
the fossa are seen the spheno-temporal suture,
the spinous process, and the spinous and oval
foramina of the sphenoid bone. The narrow
inner boundary is formed by the external ptery-
goid plate of the sphenoid; behind and below
the fossa is open. At the bottom of the zygo-
matic fossa is situated the pterygo-maxillary
fissure, forming the external orifice of the
spheno-maxillary fossa, which is a cavity
situated between the tuberosity of the upper
jaw in front, and the pterygoid process and
palate bone behind : in this fossa are five holes,
viz. three which open into it from behind, the
foramen rotundum, the vidian or pterygoid,
and the pterygo-palatine ; one opening inter-
nally at the upper part; the spheno-palatine ;
one below, the upper orifice of the posterior
palatine canal. The zygomatic fossa presents
also at its upper and anterior part, the spheno-
maxillary fissure, which is directed from within
outw^ards and forwards, and is formed inter-
nally by the orbitar processes of the palate and
upper maxillary bones, externally by the orbitar
plate of the sphenoid, and at its outer extremity,
which is large, by the malar bone ; it forms a
communication between the orbit and the zygo-
matic fossa. Its inner end joins the spheuoidal
and the pterygo-maxillary fissures, with the
former of which it forms an acute, and with
the latter, a right angle: thus these three
fissures may be considered as branching from
a common centre at the back of the orbit; they
give passage to a number of vessels and nerves,

and establish communications between the cavL
ties of the face and cranium.

The superior or cranial region is very irregu-
lar, and is immoveably united to the cranium.
It presents along the median line, from before
backwards, the articulation of the nasal bone,
with the nasal spine of the frontal, the union
of this spine with the perpendicular plate of
the ethmoid, the articulation of this plate with
the vomer, the articulation of the vomer with
the sphenoid.

Along the sides, from within outwards, are
seen the arched roof of the nasal fossae formed
in front of the nasal bones, in the middle by
the cribriform plate of the ethmoid, and behind
by the body of the sphenoid. External to these
parts are found the base of the pterygoid process,
the articulation of the palate with the body of
the sphenoid bone, the pterygo-palatine canal,
the spheno-palatine foramen ; next the spongy
masses of the ethmoid united behind with the
sphenoid, and anteriorly with the os frontis;
and still more forwards are seen the articula-
tions of this bone with the lachrymal, upper
maxillary, and nasal. To the outer side of
these articulations is the triangular roof of the
orbit, limited externally by the sphenoid and
malar bones and by the sphenoidal fissure.
Next may be observed the orbitar plates of the
sphenoid, forming the greater part of the outer
wall of the orbit, and lastly the zygoma. The
inner border of the orbitar plate of the frontal
bone presents the fronto-lachrymal and the
frontal-ethmoidal sutures ; the outer border the
spheno-frontal and fronto-jugal sutures.

The internal structure of the face appears
to be very complex, presenting several cavities
and divisions which give it at the same time
strength and lightness. The arrangement of
these parts may be understood by observing,
1. the perpendicular septum formed by the
ethmoid and vomer, which divides the upper
part of the face into two equal halves ; 2. in
each half three horizontal divisions, viz. an
upper or frontal, which separates the cranium
from the orbit ; a middle or maxillary, placed
between the orbit and the cavity of the nose,
and an inferior or palatine situated between the
nose and mouth; 3. three outer divisions, viz.
an upper or spheno-jugal, forming the outer
wall of the orbit, and separating that cavity
from the temporal fossa; a middle, formed by
the maxillary tuberosity which separates the
cavity of the nose from the spheno-maxillary
and zygomatic fossae ; an inferior, formed by
the raraus of the jaw; 4. above and at the
centre the ethmoid and lachrymal bones sepa-
rate the orbits from each other and from the
cavities of the nose.

The principal cavities of the face are the
orbits, the nasal fossae, and the mouth ; and
with these all the rest are more or less con-
nected. These cavities will be described under
the several articles, ORBIT, NOSE, MOUTH.

Mechanism of the face. — The face forms a
structure which combines both strength and
lightness ; the former quality is owing to the
arched form of its exterior and to the strong
pillars of supports (to be presently described;

218

FACE.

which connect its different parts to each other
and to the cranium. The lightness of the face
depends upon the thinness of some of its
bones, and the large cavities which it com-
prises. The two upper maxillary bones form
by their alveolar border and palatine arch a
strong platform, from which ascend five osseous
pillars; one median, formed by the vomer and
the perpendicular plate of the ethmoid; two
at the sides of the nose, formed by the nasal
process of the superior maxilla ; and at
the lateral parts of the face two others,
formed by the malar processes of the upper
jaw and the malar bones. All these pillars
connect the upper jaw with the bones of the
cranium, and contribute by their form, strength,
or extent of articulation to resist or diffuse the
concussion of violent blows applied to the face.
The strength of the lower jaw depends upon
its arched form and upon its mobility, but,
from its exposed situation, it is notwithstand-
ing frequently broken.

Development of the face. — The development
of the face consists not merely in its general
increase, but in the relative proportion of its
several parts at different periods of life. As
the face contains the organs of sight, smell,
and taste, together with those of mastication,
we shall not expect to find it much deve-
loped in the foetus and infant while these
parts are scarcely called into action ; accord-
ingly, we observe the vertical diameter of the
face (strictly so called) to be very short, which
is owing to the slight elevation of the ethmoid,
the lachrymal, the upper and the lower maxil-
lary bones, consequent on the imperfect deve-
lopment of the nasal cavities, the maxillary
sinuses, and the teeth; see Jig. 131. The

orbits, indeed, are remarkably large, but this
depends upon the great development of the
cranium and the breadth of the orbitar plates
of the frontal bones, for in their vertical dia-
meters the orbits are not remarkable at this
period of life.

The transverse diameter of the face in the
fetus is considerable across the orbits, but
below these it is narrower in proportion than in
the adult. The other chief peculiarities of the
foetal face are, the small size of the nasal cavi-
ties, the absence of the canine fossae, depend-
ing partly on the small vertical diameter of the
upper jaw, and partly upon the teeth being
still lodged within it; the prominence and
shortness of the alveolar borders of both jaws,
the vertical direction of the symphysis menti,
which even inclines from above downwards
and a little backwards; the remarkable con-

vexity of the maxillary tuberosities, owing to
the teeth being lodged within them ; and the
great obliquity from above downwards and
forwards of the posterior apertures of the nose,
arising from the smallness of the maxillary
sinuses ; the small antero-posterior diameter of
the palatine arch, which depends upon the
same cause; and, finally, the oblique direction
of the rami of the lower jaw: see Jig. 377,
vol. i. p. 742.

In the adult, as the ethmoid and turbinated
bones together with the maxillary sinuses
become developed, the nasal cavities enlarge,
especially in their vertical diameter; above,
they communicate with the frontal sinuses,
which are now fully formed and projecting ;
the jaws have become deeper from the protru-

Fig. 132.

sion of the teeth, which cause a considerable
addition to the vertical diameter of the face ;
below, the palatine arch has extended back-
wards with the development of the maxillary
sinuses, and the posterior apertures of the nose
have become in consequence nearly vertical :
the rami of the lower jaw form also nearly
a right angle with its body.

In old age the vertical diameter of the face
decreases in consequence of the loss of the
teeth and the contraction of the alveolar borders
of the jaws, which touch each other when the
mouth is closed ; the rami of the jaw resume
the oblique direction of childhood, (Jig. 133;)

Fig. 133.

FACE.

219

and the symphysis inclines from the shrunken
alveolar border downwards and forwards to the
base of the bone, and gives to the chin the
projecting appearance which is so character-
istic of this period of life.

The articulations of the face comprise those
of the upper and that of the lower jaw.

The articulations of the bones of the upper
jaw with each other and with those of the cra-
nium are all of the kind called suture, but they
present considerable variety in the extent, form,
and adaptation of their articular surfaces.
Those bones of the face which contribute to
form its columns of support, and to which this
part of the head owes its strength and resistance
to violence, have their articular surfaces for the
most part broad and rough, presenting emi-
nences and depressions which are adapted to
those of the contiguous bone; examples of this
firm articulation are seen, 1. at the anterior
part of the intermaxillary suture, where the two
palatine plates unite and form the horizontal
column or base of the upper jaw; 2. at the
nasal columns, where the nasal bones and the
nasal processes of the upper maxillae unite with
the frontal; 3. on the sides of the face, or
where the bones form their lateral or malar
columns, viz. at the jugo-maxillary and jugo-
frontal articulations. The spheno-jugal articu-
lation, seen within the orbit, and the zygomatic
or temporo-jugal, though formed by the union
of comparatively narrow surfaces or borders,
derive strength from their irregularity, and, in
the case of the zygomatic suture, from its in-
dented form, which maintains its security from
vertical blows, as the curved direction of the
zygoma protects it from lateral injury.

Those sutures of the face which are, strictly
speaking, harmonic, are such as are not exposed
to any considerable pressure; they present,
nevertheless, some varieties in their mode of
juxta-position. In some the adaptation is
direct, as in the pterygo-palatine. In others
one border or surface is received by another
(schindylesis), as in the articulations of the
vomer with the sphenoid above, and with the
groove in the palatine plates of the upper max-
illary and palate bone inferiorly. Sometimes
the surfaces are simply applied against each
other, as the nasal plate of the palate bone on
the nasal surface of the upper maxillary.
Lastly, the edges may alternately overlap each
other, as those of the nasal and upper maxillary
bones.

In all the sutures of the face, whatever may
be the adaptation of the osseous surfaces, we
find interposed a thin layer of cartilage uniting
the contiguous surfaces of the bones. This is
easily shown in some of the sutures by mace-
ration, and only disappears in places as some
of the bones become united with advancing
age.

The great number of pieces of which the
upper jaw consists, and the varying form and
direction of the sutures, all contribute, with the
figure of the bones themselves, to give strength
to this part of the skull, and to break the force
of blows by diffusing them over a widely ex-
tended surface.

The sutures of the face derive their names
from the bones which contribute to form them;
thus we have between the orbits the fronto-
nasal, fronto-maxillary, and fronto-lachrymai
sutures, all contributing to form part of the
transverse suture. (See CRANIUM.) Lower
down we find the nasal, the naso-maxillary,
and the lachrymo-maxillary, which turns at
right angles backwards along the inner wall of
the orbit into the ethmoido-maxillary and pa-
lato-orbitar sutures. On the outer side of the
orbit may be observed the fronto-jugal and
spheno-jugal sutures; on the zygomatic arch
the temporo-jugal suture ; and below the pro-
minence of the cheek, the jugo-maxillary
suture, which is seen both on the anterior and
posterior surface of the upper jaw. On the
roof of the mouth are seen the longitudinal and
the transverse palatine sutures, the former
formed by the intermaxillary in front, and by
the inter-palatine suture behind : the latter is
often termed the transverse or horizontal palato-
maxillary suture. There are some other sutures
within the nose which it is unnecessary to enu-
merate.

The lower jaw articulates with the cranium
by diarthrosis : this important joint will be
particularly described in the article TEMPORO-

MAXILLARY ARTICULATION.

The bones of the face are invested with
periosteum or a fibrous membrane, which is
variously modified and arranged in the orbits,
nose and mouth, &c.

ABNORMAL CONDITIONS OF THE BONES OF
THE FACE.

In the true acephalous foetus the bones
of the face as well as those of the cranium
are of course wanting, but the former are
generally found in what are termed the false
Acephalia (see ABNORMAL CONDITIONS OF
THE CRANIUM) ; it sometimes happens, not-
withstanding, that the bones of the face are but
imperfectly developed, presenting a variety of
conformations which it is unnecessary to parti-
cularise. The bones of the face, in some cases
alone, and in others in conjunction with those
of the cranium, not unfrequently acquire a de-
gree of development quite disproportionate with
the rest of the skeleton. In Corvisart's Journal
de Medecine the case of a Moor is cited, whose
head and face were so enormous that he could
not stir abroad without being followed by the
populace. It is related that the nose of this
man, who was half an idiot, was four inches
long, and his mouth so large that he would bite
a melon in the proportion that an ordinary per-
son would eat an apple. I have now before
me the skull of a native of Shields, who was
remarkable during life for the length of his
face ; the entire head is large, but the bones of
the face, and particularly the lower jaw, are
enormously long. The abnormal development
of the facial bones generally affects one jaw
only, and more frequently the lower, as in the
example just mentioned. Other cases, but they
are much more rare, have been related in
which the lower jaw was disproportionately
small. When, from either of the circumstances

220

FACE.

which have been just mentioned, the develop-
ment of the two jaws is unequal, the corre-
spondence of their alveolar borders is lost, and
mastication becomes in proportion imperfect :
in mammiferous animals the unequal size of
the lower jaw, by preventing suckling, is often
a cause of death. The bones of the face are
much more symmetrical than those of the cra-
nium, and rarely present the disproportion in
their lateral development which is observed in
the latter.

Under the head of defect or arrest of deve-
lopment may be noticed, 1. the occasional ab-
sence of some of the bones, as for example, the
lachrymal or the vomer; 2. the existence of
fissures, or non-union of the upper maxillary
bones, and, as a more rare case, the separation
of the two halves of the lower jaw. Fissures
of the upper jaw may exist in various degrees,
and may occur with or without a corresponding
cleft in the soft palate and lip ; it may appear
as a mere slit along the middle of the roof of
the mouth, forming a narrow communication
between that cavity and one side of the nose ;
or it may extend along the whole of the pala-
tine arch, and be continuous behind with a
similar division of the soft palate, without, at
the same time, being accompanied with hare-
lip. Sometimes the aperture is very wide, and
the palatine plates of the upper maxillary and
palate bones are almost entirely wanting ; in
this case the vomervand middle cartilage of the
nose are also partially or entirely absent ; and
there is both hare-lip and cleft of the soft
palate, so that the mouth, both sides of the
nose, and the pharynx are laid into one great
cavity. When the fissure exists at the anterior
part of the palate only, it almost invariably
occurs at the suture which has been described
between the maxillary and intermaxillary bones,
so that the cleft separates the canine from the
lateral incisor tooth ; when the fissure occurs
on both sides of the face, the four incisor teeth
are separated from the others and lodged in an
alveolar border, which usually in this case
projects more or less towards the lip, in which
there is also commonly a single or double cleft
or hare-lip. Sometimes the fissure occurs in
the intermaxillary bone itself between the lateral
and middle incisor teeth, and then we find a
single incisor on one side and three on the op-
posite : it is very rarely that the cleft exists in
the median line between the two intermaxillary
bones.

Among the arrests of development which
occur in the bones of the face may be enume-
rated a fissure which occasionally extends
across the lower border of the orbit, and a
suture which sometimes divides the os jugum
into two pieces.

The union which not unfrequently takes
place between the bones of the upper jaw by
the obliteration of their sutures, is commonly
the effect of age, and usually occurs between
the bones of the nose, between the vomer and
sphenoid, and between the inferior turbinated
and upper maxillary bones. Wounds and frac-
tures of the bones of the face readily unite.
Those most subject to these injuries are such

as are the most prominent, viz. those of the
nose, cheek, and lower jaw ; the last is the
most frequently broken. The alveolar pro-
cesses and the delicate bones in the orbit and
nose are also liable to injury. The bones of
the face are subject, like the rest, (though not
so commonly as those of the cranium,) to hy-
pertrophy and atrophy. Exostosis appears most
frequently on the upper jaw, in the orbit, or
along the alveolar border on the outer surface
of the bones ; on the lower jaw it is situated
usually along the alveolar border, at the angle
or on the body of the bone. Inflammation of
the periosteum and bones of the face occurs
spontaneously or as the result of injuries or
disease, and presents the usual phenomena.
Abscesses also take place either within the
cancellous structure of the more solid bones,
or in the cavities which they contain ; when
matter forms within the antrum, it may be
evacuated by extracting the canine or the large
molar tooth, which often projects into this ca-
vity, and then piercing through the bottom of
their sockets. When necrosis affects the bones
of the face, its ravages are seldom repaired (as
in the case of cylindrical bones) by the pro-
duction of new osseous matter ; some attempts
at reparation after the separation of a seques-
trum have been, however, observed in the lower
jaw. Caries, either simple or connected with
syphilitic or strumous disease, may attack
nearly all the bones of the face, but it more
particularly affects the alveolar borders of the
jaws and the delicate bones about the nose and
palate ; it is often attended with partial ne-
crosis. Caries of the face may occur as the re-
sult of malignant ulcerations, of lupus, or of the
various forms of cancer which affect the soft
parts. Both the upper and lower jaw are sub-
ject to osteo-sarcoma, commencing either on the
surface or in the interior of the bones, and ac-
quiring sometimes an enormous size, so as to
encroach on the orbit, nose, and mouth, and
materially to impede the motions of the lower
jaw. For these growths and others more sim-
ple, of & fibrous OY jibro-cartilaginous structure,
large portions (sometimes amounting to nearly
the whole) of the upper or lower jaw have been
removed with success. Cyst-Like tumours, con-
taining a serous rluid, have been found in the
lower jaw. The more intractable diseases of
medullary sarcoma and fungous growths of va-
rious kinds also attack the bones of the face.
A few cases of hydatids (the acephalo-cystus)
have been met with in the upper jaw.

THE MUSCLES OF THE FACE

are arranged around the orifices of the eyelids,
the nose, and the mouth, and may be divided
into constrictors and dilators of these apertures.
The nostrils, however, undergo but little vari-
ation in their dimensions, being maintained
permanently open by the elastic cartilages
which form them. The eyelids also contain
elastic cartilages, which are moulded upon
the front of the globe over which they glide in
obedience to the muscles which dilate or con-
tract the orifice between them. The mouth,
which is the most mobile of the facial aper-

FACE.

221

tures, is also furnished with its contractor or
sphincter muscle, and with many dilators
which radiate from it at various angles.

All the muscles of the face are superficially
situated, and most of them are subcutaneous.

In the palpebral regions, or about the eye-
lids on each side, are placed, 1. a constrictor,-
or the orbicularis palpebrarum, of which the
corrugator supercilii is an associate; 2. the
levator palpebrte and the occipito-frontalis,
which are dilators, and antagonists of the two
former muscles.

The orbicularis palpebrarum, (naso-palpebral,
Chauss.) is a flat oval muscle, situated im-
mediately underneath the skin, to which it
adheres, and covering the base of the orbit
and the superficial surface of the eyelids ; in
the middle it presents a transverse aperture,
which is the orifice of the palpebra, varying
in size according to the individual, and giving
apparently a greater or less magnitude to the
globe itself, which, however, is of nearly uni-
form dimensions in different persons. The
orbicularis, like the other sphincter muscles,
consists of concentric fibres, but it is peculiar
in having a fixed tendon on one side, from
which a great part of the fibres arise; this
tendon of the orbicularis, or ligamentum pal-
pebrse, which is situated horizontally at the
inner corner of the eye, is about two and a
half lines in length, and half a line in breadth;
it arises from the anterior border of the lachry-
mal groove in the nasal process of the upper
maxillary bone, and passing horizontally out-
wards in front of the lachrymal sac, divides
into a superior and an inferior slip, which are
attached to the inner extremities of the corres-
ponding eyelids. The tendon at first is flat-
tened anteriorly and posteriorly, but afterwards
becomes twisted so as to present horizontal
surfaces. From its posterior part is detached
a slip of fibres (the reflected tendon of the
orbicularis), which proceeds backwards to-
wards the os unguis, and forms the outer wall
of the lachrymal canal.

The orbicularis arises, 1. from the borders
and surfaces of this tendon and from its
reflected slip; 2. from the internal angular
process of the frontal bone and from the fronto-
maxillary suture; 3. from the nasal process of
the upper maxillary bone ; and, 4. by short
tendinous slips from the inner third of the lower
border of the orbit. From these origins the
upper and lower fibres of the muscle take a
curved direction outwards, their concavity look-
ing towards the aperture of the lids, and fol-
lowing the course of the upper and lower
borders of the orbit, which they overlap.
They unite at the outer side ; not, however, by
a tendinous raphe or septum, as some have
described, but simply by the mingling of their
fibres. Each half (the upper and lower) of
the orbicularis consists really of two sets of
fibres ; one, which covers the margins of the
orbits, and forms the circumference of the
muscles, is strong, tense, and of the usual
reddish colour ; it arises from the direct ten-
don, and from the frontal or upper maxillary
bone. These form the orbicularis properly so

called. The other set, which is pale and thin,
covers the lids and proceeds almost in a hori-
zontal direction outwards from the palpebral
bifurcation of the orbicular tendon : this forms
the ciliary or palpebrales. These two sets of
fibres, as we shall presently see, are distin-
guished as much by their functions as by their
appearance.

Relations. — The superficial surface of that
part of the muscle which covers the lids
(the palpebrales) is connected to the skin by
delicate loose cellular tissue entirely destitute
of fat. The stronger fibres which form the
outer part of the muscles are closely adherent
to the integument by cellular tissue more
densely woven, and presenting more or less
fat. The posterior surface covers, above, the
lower part of the frontalis and the corrugator
supercilii, with whose fibres it is connected ;
internally the corresponding part of the fibro-
cartilages of the lids, the lachrymal sac, and
the inner border of the orbit externally, the
outer border of the orbit and part of the tem-
poral fascia inferiorly, the upper part of the
malar bone, the origins of the levator labii
superioris proprius, the part of the levator
labii superioris alaeque nasi, and the inferior
border of the orbit. At its circumference this
muscle corresponds, by its upper half, to the
frontal, which it slightly overlaps, and inter-
nally to the border of the pyramidalis, with
which it is connected; externally it is free.
Below its border is free, covering the origin,
and giving some fibres to the lesser zygomatic ;
and internally it is separated from the levator
labii superioris alaeque nasi by cellular tissue,
in which runs the facial vein. The central
fibres cover the palpebral fascia and the lids,
which separate them from the conjunctiva.

Action. — The action of this muscle resem-
bles that of other sphincters, the curved fibres
in contraction approaching the centre ; but as
in the orbicularis palpebrarum these fibres are
fixed at the inner side, it follows that the skin
to which the muscle is attached by its anterior
surface is drawn towards the nose, and when
the muscle is in strong action, becomes cor-
rugated, presenting folds which converge to-
wards the inner angle of the eye ; above, where
the effect of the muscle on the skin is most
marked in consequence of its closer connec-
tion with the integuments, the brow and the
skin of the forehead are drawn down by it
and its associate the corrugator; the lower
fibres when in strong action, draw the cheeks
upwards and inwards. Like the other sphinc-
ters, also, this is a mixed muscle. Those
fibres which may be supposed to be voluntary,
are the larger and outer ones, which corres-
pond to the border of the orbit, and are of a
red colour. The iuvoluntary fibres are those
thin ones which cover the lids, are of a pale
colour, like the muscles of organic life, and
arise from the palpebral subdivisions of the
horizontal tendon. They contract involuntarily
while we are awake, in the action of winking,
and during sleep in maintaining the lids closed;
they also act under the will in closing the
lids, particularly the upper. It appears then

222

FACE.

that the orbicularis may be divided both ana-
tomically and physiologically into two sets of
fibres; an outer, or orbicularis proper, which is
entirely a voluntary muscle, and an inner
(the palpebralis) which is both voluntary and
involuntary in its action. These fibres may
act independently of each other, for in wink-
ing and during sleep the palpebralis contracts,
while the orbicularis is quiescent ; and the
orbicularis may contract even strongly, as when
we peer with the eyes under the influence of a
strong light, while the fibres of the pal-
pebrales are relaxed. It has been supposed,
however, by some, that during sleep the lid
is closed simply by the weight of the upper
palpebra, and the relaxation of its proper
elevator muscle, but this seems in contra-
diction to the fact that we meet with resistance
in endeavouring to unclose the lids of a sleep-
ing person.

Corrugator supercilii, which is the associate
of the orbicularis palpebrarum, has been al-
ready described, together with the occipito-
frontalis, which is the antagonist of those
muscles. See CRANIUM, MUSCLES OF THE,
vol. i. p. 747.

Levator palpebra superioris ( orbito-palpe-
bral), though situated within the orbit, is
nevertheless the direct antagonist of the palbe-
bralis, and is therefore properly described with
these muscles of the face. It is a thin trian-
gular .muscle, which arises by a narrow slen-
der tendon at the back of the orbit from the
inferior surface of the lesser wing of the sphe-
noid bone, above and in front of the optic
foramen ; from this origin the fibres proceed
almost horizontally forwards under the roof of
the orbit, and gradually spreading and be-
coming thinner as they advance, curve over
the globe of the eye, and are inserted into the
upper border and anterior surface of the upper
lid.

Relations, — Its upper surface is in contact,
behind, with the frontal branch of the ophthal-
mic nerve, which with some cellular tissue
alone separates it from the periosteum of the
roof of the orbit ; anteriorly with cellular tissue
and the palpebral fascia, which separate it from
the orbicularis. The lower surface behind rests
upon the superior rectus oculi, with which it
is connected by cellular tissue, and anteriorly
on the conjunctiva and upper lid.

Its action is to raise the upper lid, and to
draw it backwards over the globe and under
the supra-ciliary ridge. There is no separate
muscle to effect the depression of the lower
lid, that action being occasioned, as Sir C.
Bell ingeniously suggested, by the protrusion
of the eyeball.

Nasal region. — The muscles of this region,
some of which are common to the upper lip,
are, \. the pyramidalis; 2. the levator labii
superior is alaque nasi; 3. the triangularis
nasi ; 4. the depressor al<e nasi.

Pyramidalis is situated between the brows,
and may be considered as a prolongation of
the inner fibres of the frontalis : it is of a
triangular form ; its base above is continuous
with the fibres of the frontalis ; below it con-

tracts and is inserted into the aponeurotic ex-
pansion of the triangularis nasi. It is sepa-
rated from its fellow slip of the opposite side
by a groove of cellular tissue.

Relations. — Its superficial surface adheres
to the skin; its deep one rests on the nasal
eminence of the frontal bone, the nasal bones,
and part of the lateral cartilage of the nose.

Use. — If this muscle acts at all on the nose,
it is by drawing up the skin when the occipito-
frontalis is in action. Its more probable use
is to give a fixed point to the frontalis, and to
draw down the inner extremity of the brows
and the skin between them.

Levator labii superioris al&que nasi. — (T,
Jig. 134.) This is a thin, long, triangular

Fig. 134.

muscle, placed nearly vertically on each side
of the nose. It arises narrow from the outer
surface of the nasal process of the upper max-
illary bone, immediately beneath the tendon
of the orbicularis palpebrarum. It descends
obliquely outwards, becoming broader, arid
terminates inferiorly by two slips, an internal
short one, which is attached to the cartilage
of the ala nasi, or to the fibrous membrane
which invests it; and an outer longer slip,
which is attached to the skin of the upper lip
near the nose, and mingles its fibres with the
transversalis nasi, the levator labii superioris
proprius, and the orbicularis oris.

Relations. — Covered by the skin, and over-
lapped a little above by the orbicularis pal-
pebrarum, this muscle covers the nasal process
of the upper maxillary bone, the triangularis
nasi, and the depressor alee nasi. Its inner
border above corresponds to the pyramidalis.

Its action is to raise the ala of the nose and
the adjacent part of the upper lip; in so doing
it dilates also the nostril and becomes a muscle
of inspiration. When strongly thrown into
action, it corrugates the skin of the nose trans-
versely.

FACE.

Tr'mngularis nasi ( (ransversalis was*, com-
pressor naris, Albin.) (n, Jig. 134), is a very
thin triangular muscle, placed transversely on
the middle of the side of the nose. To expose
its origin, the levators of the upper lip must
be turned aside, and the skin of the nose very
carefully dissected off. Its origin is then seen
as a narrow slip from the inner part of the
canine fossa, below the ala nasi ; from this
point the fibres radiate inwards and upwards,
and expand into a very thin aponeurosis,
which crosses the ala nasi and the lateral car-
tilage of the nose to be confounded along the
median line with that of the opposite muscle,
and with the pyramidalis. Bourgeiy describes
two other origins, one superficial, attached to
the skin below and to the outside of the ala
nasi, and a middle one crossing and connected
with the fibres of the levator of the upper lip.

Relations. — It is covered at its origin by the
levator labii superioris alaeque nasi, and inter-
nally by the integuments to which it super-
ficially adheres ; it rests on part of the upper
jaw, on the cartilages of the ala, and on the
lateral cartilage.

Its action is yet undetermined by anato-
mists, some considering it a compressor or
constrictor of the nose, others as a dilator or
elevator. Cruveilhier thinks that its action
varies with the form of the ala, which, when
convex, makes it a compressor, when concave
a dilator. Perhaps, as M. Bourgeiy suggests,
its action depends upon which extremity is
fixed, and that, when its base is fixed, its
superficial fibres dilate the nostrils and draw
the lip upwards and inwards, and that, when
the muscle acts towards its maxillary attach-
ment, it compresses the nostril.

Depressor ala nasi (mmculus my rt if or mis),
(Jig. 134.) To expose this muscle the upper
lip should be reversed, and the mucous mem-
brane divided on each side of the fraenum labii.
It is a short flat muscle, radiating upwards
from the myrtiform fossa of the upper jaw,
where it arises towards the ala of the nose,
into the posterior part of which it is inserted
below and internal to the dilator nasi. This
muscle really consists of two sets of fibres,
one which has been just described, the other
which is in front of this and is attached above
to the ala and septum of the nose, below to
the inner surface of the orbicular fibres. The
first set, or the naso-maxillary fibres, are de-
pressors of the alae and contractors of the
nostrils ; the second, or naso-labial fibres, are
elevators of the upper lip.

Relations. — It is covered by the mucous
membrane of the upper lip, by the orbicularis
oris, and by the levator labii superioris alaeque
nasi; it covers the myrtiform fossa of the
upper jaw : its inner border is separated from
its fellow by the fraenum.

A dilator al& nasi is described by Bourgery
as a little triangular muscle, consisting of
fibres placed underneath the skin lying on the
outside of the ala nasi, from the posterior part
of whose cartilages the fibres arise by a narrow
point, and then radiate upwards, outwards,

135.

and downwards, to be mingled with the fibres
of the elevators of the lip, the orbicularis, and
the naso-labial, all being attached to the skin.
This muscle, according to Bourgery, directly
draws the ala outwards, and is consequently a
dilator of the nostril.

The labial region presents in the centre, 1 .
a sphincter (the orbicularis oris), with which
are associated two muscles on each side, the
depressor labii superioris and the levator labii
inferioris: all these are contractors or com-
pressors of the lips : 2. a number of anta-
gonist muscles or dilators, which comprise
many muscles, which on each side radiate
from the lips, or from their commissure at
different angles. They are, above, the levator
labii superioris proprius and the zygomaticus
minor; below, the depressor labii inferioris at
the commissure, the buccinator, the levator
anguli oris, and the depressor anguli oris. By
some anatomists the muscles of this region of
the face are divided into, 1. the sphincter,
and, 2. the elevators and depressors of the
lips.

Orbicularis or sphincter oris (labial, Chauss.
and Dum.) (o o, Jig. 134) is a thick oval
muscle, placed transversely around the aper-
ture of the mouth, which varies in size in dif-
ferent persons, but bears no relation to the size
of the buccal cavity. It extends above from
the free border of the upper lip to the nostrils,
and inferiorly from the free border of the lower
lip to the depression above the chin. Its
fibres, arranged in successive layers, consist
of two semi-elliptical halves, one superior, the
other inferior, which are on each side united
externally to the commissure of the lips by
decussating each other, and mingle also at
their circumference with the dilators which are
attached to it. These fibres are concentric,
with their curve towards the lips ; the most
central run nearly in a horizontal direction
along the borders of the lips, and take a di-
rection forwards, which gives the prominence
to the lips which is so remarkable in the
Negro. The outer fibres are more curved,
and receive between their layers the extensors
of the lips, which are attached around them.
This is the only muscle of the face which has
no attachment to bone.

Relations. — The anterior surface is closely

224

FACE.

connected with the thick skin which covers it.
The posterior surface and free border is covered
with the mucous membrane of the mouth, from
which it is only separated in places by the
labial glands, by the coronary vessels, arid by
numerous nerves. Its outer border or circum-
ference receives the antagonist muscles which
are attached around it.

Actions. — The orbicularis enjoys a very va-
ried and extensive motion, and possesses the
remarkable power of either acting as a whole
or in parts. Its simple use is to close the
mouth, in correspondence with the elevation
of the lower jaw, by bringing the red borders
of the lips in contact, or by pressing them to-
gether firmly. But the upper or lower labial
fibres can act separately, or the fibres at either
commissure, or the fibres of one side may con-
tract, while the others are quiescent, so that
different parts of the lips may be moved by
different portions of the muscle, which is made
in this way to antagonize in turn the different
muscles which are attached around.

The lips may be thrown forward by the con-
traction of the labial and commissural fibres
forming in strong action a circular projection,
as in the action of whistling, or, when more
relaxed, in blowing. By the contraction of the
inner labial fibres the lips may, on the contrary,
be turned inwards so as to cover the teeth. The
play of the mouth, however, which contributes
in so eminent a degree to the expression of the
face, depends not only on the orbicularis, but
upon its association with the different muscles
which are attached around it.

Naso-labialis is a small subcutaneous slip of
fibres, only distinctly seen in strong muscular
lips. It is situated on each side of the median
depression of the upper lip, and arises from
the lower septum of the nose at the back part
of the nostril ; it proceeds downwards and out-
wards, and is soon lost in the fibres of the or-
bicularis. It is an elevator of the middle part
of the upper lip, and is considered by some as
an attachment of the orbicularis.

Levator labii superioris (lr, Jig. 134) is a
thin, flat, quadrilateral muscle, situated about
the middle of the face, and nearly on the same
plane with the levator labii superioris alaeque
nasi. It arises from the malar and upper
maxillary bones where they form three-fourths
of the lower border of the orbit, by short ten-
dinous slips ; from this origin the fibres, con-
verging a little, take a direction downwards
and inwards, and are inserted partly super-
ficially into the skin of the upper lip, and
partly into the fibres of the orbicularis, between
the insertion of the levator labii superioris
alaeque nasi and the lesser zygomatic, with
which its fibres are partly covered and con-
founded.

Relations. — Its anterior surface is covered
above by the orbicularis palpebrarum, below
by the skin and by the muscles with which its
fibres are mingled at its insertion. Its posterior
surface covers the infra-orbitar vessels and
nerves at their exit from the infra-orbitar fo-
ramen, which, with some fat and cellular tissue,

separates it from the upper part of the levator
anguli oris. It covers also part of the trian-
gularis nasi.

Its action is to raise and draw a little out-
wards the upper lip.

Zygomaticus minor (3', fig. 134) is a narrow
rounded muscle, often wanting It arises from
the external surface of the os malae, and fre-
quently also from the deep fibres of the orbicu-
laris palpebrarum, by which its origin is co-
vered ; it proceeds downwards and inwards,
and is attached to the skin and orbicuiaris pal-
pebrarum above the commissure of the lips,
where its fibres are also confounded with those
of the levator labii superioris proprius.

Relations. — This muscle is covered in front
by the orbicularis palpebrarum and skin ; its
posterior surface conceals a part of the levator
anguli oris and of the labial vein.

Action. — It is an associate of the levator
labii superioris, and contributes to raise the
upper lip and draw it a little outwards.

Zygomaticus major (3, Jig. 134), placed to
the outer side and 'a little below the preceding
muscle, is of a rounded form, and arises by
short tendinous slips from a depression on the
posterior part of the outer surface of the os
malse, near its lower border. Its fibres proceed
downwards and inwards, nearly parallel with
those of the lesser zygomatic, but much longer;
and expanding a little below, they become con-
founded with the fibres of the orbicularis oris
at their commissure, and with those of the
levator labii superioris, levator anguli oris, and
depiessor anguli oris. Its superficial fibres are
attached to the skin.

Relations. — This muscle is surrounded by
fat, which separates it from the skin. By its
deep surface it rests above on the os mala and
the masseter; below, it is separated by fat
from the buccinator and the levator labii supe-
rioris : it crosses also the labial vein.

Its action carries the commissure of the lips
upwards and outwards, and is intermediate
between the action of the levator and the buc-
cinator : it is the antagonist of the levator an-
guli oris in drawing the lip outwards; its
associate in raising it. When both these mus-
cles act, the commissure of the lips is directly
raised .

Levator anguli oris (musculus caninus) : (c,
fig. 136). — To expose this, the levator labii
superioris must be removed. It is a flat qua-
drilateral muscle, which arises from the middle
of the canine fossa of the upper jaw, and be-
coming somewhat narrower takes a direction
downwards and a little outwards and forwards,
to terminate at the commissure of the lips,
where its fibres mingle with those of the orbi-
cularis, the buccinator, and the depressor
anguli oris.

Relations. — Deeply placed above, its ante-
rior surface is covered by the infra-orbitar ves-
sels and nerves, and by fat, which separate it
from the levator labii superioris and the lesser
zygomatic. Below it is covered by the zygo-
maticus major and the integument. The pos-
terior surface of this muscle rests on the upper

FACE.

maxillary bone, on the mucous membrane of
the mouth, and on the buccinator. Its action
is to raise the commissure of the lips, and
draw it a little inwards. Its action ^vhen as-
sociated with that of the zygomatics has been
already explained.

Depressor anguli oris (triangularis orls) (ty
Jig. 134) is a thin, triangular, subcutaneous
muscle, situated at the lower part of the face.
It arises by a broad base from the lower border
of the inferior maxilla, and from the surface of
the bone between this border and the external
oblique line, extending from the chin to within
half an inch of the masseter. The fibres con-
verge and ascend towards the commissure of
the lips, the posterior fibres taking a direction
upwards and forwards, the middle nearly ver-
tical, and the anterior describing a curve up-
wards and backwards: they all terminate at the
commissure of the lips, where they become
united with those of the orbicubris and of the
buccinator, and more superficially with the
great zygomatic and levator anguli oris.

Relations. — Its superficial surface is covered
by the skin and by the fibres of the platysma,
with which it is mingled. Its deep surface
rests upon part of the depressor labii inferioris
and buccinator : above it is connected with all
the muscles of the commissure and with the
skin.

Action. — This muscle draws down the angle
of the mouth, and in this respect is the anta-
gonist of the great zygomatic and levator an-
guli oris.

Depressor labii inferioris (quadratus menti),
(d, Jig. 136, 137) flat and of a square form, is
placed internal to the preceding, which partly
conceals it. It arises from the inner half of
the external oblique line of the lower jaw, and
also from the platysma, with whose fibres it is
continuous. Its fibres, which are parallel, pro-
ceed upwards and inwards to be attached to
the lip ; the deep fibres mingle with those of
the orbicularis; the superficial pass in front of
that muscle, and are fixed in the skin of the
lip. The inner fibres decussate above with
those of the muscle on the opposite side;
below, with those of the levator menti.

Fig. 136.

Relations. — At its origin this muscle is co-
vered by the triangularis, and elsewhere by the
skin, to which it adheres intimately above. Its
deep surface covers part of the lower jaw, the
mental vessels and nerves, part of the orbicu-
laris oris and levator menti. Through the an-
gular interval between the two depressors of
the lower lip, the levatores menti pass to their
insertion.

Its action is to draw downwards and out-
wards one side of the lower lip; if the muscles
on both sides act, the lip is drawn downwards
and extended transversely. The stronger ac-
tions of this muscle are usually accompanied
by those of the platysma, with whose fibres,
as we have seen, it is continuous.

Levator menti (houppe du menton) (e, fig.
136,137) may be exposed by everting the lip and
dividing the mucous membrane : it is a small
round muscle, situated at the lower part of the
face, and forming on each side a great part of
the prominence of the chin. It arises in the
incisive fossa below the incisor teeth of the
lower jaw, external to the symphysis, and pro-
ceeds downwards and forwards : it passes under
the lower border of the orbicularis oris, and
emerging between the depressor labii inferioris,
expands a little to be inserted into the skin of
the chin. Its fibres below are mingled with
fat ; internally they are confounded with those
of the fellow muscle, and externally with the
fibres of the quadratus menti.

In its action this muscle raises and corru-
gates the chin, and by so doing raises also the
lower lip and throws it forward.

Fig. 137.

VOL. II,

Buccinator (b,fg. 136, 137). This muscle
is situated on the side of the cheek, and to ex-
pose it completely it is necessary to divide the
muscles attached to the angle of the mouth,
and to remove the ramus of the jaw and the
muscle attached to it. The buccinator is a
broad flat muscle, and arises, 1. behind and
in the middle from an aponeurotic line, the
pterygo-maxillary ligament or inter-maxillary
ligament, which is common to it aad the su-
perior constrictor of the pharynx, and which is

Q

226

FACE.

extended between the lower extremity of the
internal pterygoid plate of the sphenoid bone
and the posterior extremity of the internal ob-
lique line of the lower. Above, the buccinator
arises, 2. from the outer surface of the upper
alveolar process, between the first malar tooth
and the tuberosity; 3. below from the outer
side of the alveolar border opposite the three
last malar teeth. From these three origins the
fibres proceed forwards, the superior curving a
little downwards, the inferior upwards, and
the middle passing horizontally towards the
angle of the mouth, where they mingle with
the fibres of the orbicularis and the elevators
and depressors of the commissure. The infe-
rior and superior fibres become shorter as we
trace them forwards, and some of them decus-
sate at the angle of the mouth to unite with
the opposite labial half of the orbicularis.

The fibres of the buccinator are wavy, over-
lapping each other, so that they admit of great
distention, which is, however, limited by a
buccal fascia, which is given off from the
pterygo-maxillary ligament.

Relations. — The buccinator is deeply situated
behind, where it is covered by the ramus of
the jaw and the edge of the masseter, from
which it is separated by a quantity of fat,
which projects beyond the mass, fills up the
hollow in front of the masseter, and is always
found even in thin subjects. In the middle
it corresponds to the buccal vessels and nerves
and to the transverse facial artery, which runs
nearly parallel to its fibres, and to the duct
of the parotid gland, which, resting at first
upon its fibres, pierces them opposite the
second molar tooth of the upper jaw, and
opens obliquely into the mouth. A buccal
fascia covers the posterior half of the muscle.
At the commissure the buccinator is covered
by the muscles which are attached to the angle
of the mouth, and is crossed at right angles
by the external maxillary artery and vein. By
its internal surface this muscle covers the
mucous membrane of the mouth, from which
it is only separated by a layer of buccal
glands.

Action. — This muscle, being fixed behind,
above, and below, acts principally in front on
the commissure of the lips, which it draws
horizontally backwards, elongating the aperture
of the mouth transversely, and throwing the
cheek into the vertical folds which are so re-
markable in old age. In this respect it is
the direct antagonist of the orbicularis oris :
if both these muscles act together, the lips are
extended and pressed against the teeth. When
the cavity of the mouth is distended" with air
or liquids, this muscle is protruded at the
cheeks, and its fibres become separated and
curved. If now the muscle acts, the fibres
become straightened, and the fluid is expelled
from the mouth either abruptly or gradually
according to the resistance of the orbicularis.
This action of the orbicularis is exemplified
either in spirting fluids from the mouth, or
in playing on wind instruments. In mastica-
tion the buccinator presses the food from
between the cheek and gums into the cavity

of the mouth. It assists also in deglutition
when the mouth is closed, by pressing the
food backwards towards the pharynx.

Among the muscles of the face, it is ne-
cessary to allude to some parts of the platysma,
which are not only seen in this region, but
which contribute materially to the motion and
expression of the face. The platysma (p,p,p,
fig. 138) is a large, broad, membranous layer of
fibres, which extend from the upper and an-
terior part of the chest, where they commence
in the subcutaneous tissue, upwards over the
anterior and lateral part of the neck, to the
jaw and lower part of the face, where they
are inserted above. The whole superficial
surface of the muscle is subcutaneous, but
less firmly attached to the integument just
under the jaw than elsewhere. The under
surface of its cervical portion is in relation
with numerous important parts on the faces
it covers from before backwards the lower
part of the chin, the quadratus menti, the
triangularis oris, the base of the lower jaw,
the facial vessels, and part of the masseter.
The arrangement of its facial portion is all
that need be described here.

Fig. 138.

As the fibres of the muscle incline upwards
towards the median line, they meet below the
symphysis of the chin, and some ascend as
high as the levator rnenti. Externally the
fibres seem to split to enclose the depressor
anguli oris, and to proceed upwards and for-
wards with that muscle and the quadratus
menti to the lower lip and its angle. The
middle fibres are attached to the base of the
jaw, and posteriorly they mount over the

FACE.

227

angle, and are lost on the fascia of the masseter.
A curious slip crosses these transversely, de-
scending a little from the fascia covering the
parotid gland towards the angle of -the mouth.
It is the risorius Santorini, which is, however,
often wanting. The platysma draws down
the whole of the lower -part of the face, or,
acting more slightly, depresses the lower lip
and the commissure in conjunction with their
proper depressors. The slip called risorius,
on the contrary, raises the angle of the mouth.

The only fasciae of the face are, 1. a pal-
pebral fascia, which connects the convex edges
of the tarsal cartilages to the border of the
orbit; and, 2. a buccal fascia, which, ex-
tending forward from the intermaxillary liga-
ment, covers the posterior half of the buccinator
muscle : anterior to this it becomes lost in the
surrounding cellular tissue.

General review of the muscles of the face. —
With one exception, all the muscles of the
face are attached at one part to bone, and at
another either to the skin or to some other
muscle : their fibres are also red and firm at
their fixed attachment, pale and thinner at
their moveable extremity. With the exception
of the orbicularis oris, which is a symmetrical
muscle, all the others are arranged in pairs,
one on each side of the face. The mouth
being the most moveable, has by far the
greatest number grouped around it. It pos-
sesses, 1. a sphincter, the orbicularis oris,
the important action of which on the lips in
suction, respiration, whistling, blowing, and
playing on wind instruments, in speech and in
expression, has already been partly spoken of.
The associate of this muscle is' the levator
menti. 2. The antagonist of this are, a, the
naso-labialis, the transversalis nasi, the levator
labii snperioris, both proper and common to
it and the nose, and which raise the upper
lip ; 6, the depressor labii inferioris and pla-
tysma, which draw down the lower lip; c,
the buccinator, which extends the aperture of
the mouth transversely ; d, the zygomatics, the
risorius Santorini, and the levator anguli oris,
which draw the commissure upwards ; and, e,
the depressor anguli oris and platysma, which
draw it downwards.

About the eyes there are on each side, 1.
a sphincter, the orbicularis palpebrse and pal-
pebralis, with the associate, the corrugator
supercilii; 2, the dilators, the. occipato frontal is
and levator palpebrae. About the nose there
are, 1, a constrictor, the depressor alae nasi;
2. the dilators, levator labii superioris alseque
nasi and the dilator nasi ; 3. the triangularis
nasi, which probably both dilates and contracts
the orifice of the nostrils according to the
attachment, which is fixed.

The muscles of the face, including the
pyramidalis, the levator palpebrse, the naso-
labialis, and the dilator alae nasi, are sixteen
pairs in number; if we add the occipito-
frontalis, the corrugator supercilii, and the
platysma, nineteen pairs, and one symmetrical,
the orbicularis oris. Of these, four pairs
belong to the eye, three pairs to the nose, ten
pairs and one single one to the mouth : two

pairs are common to the mouth and the
nose.

The use of the muscles of the face with
respect to expression is a subject of so much
interest, and involves so many collateral facts,
that it will be better considered under the
separate article PHYSIOGNOMY. It will be
sufficient to observe here that the muscles which
express lively feeling and the gay passions,
such as the occipito-frontalis, the levator pal-
pebrarum, the levators and dilators of" the lips
and their commissure, do for the most part
either raise or draw the parts from the median
line; and that those muscles which manifest
the sadder feelings and the darker passions,
as the corrugator supercilii, the pyramidalis,
the levator menti, the depressors of the lower
lip and its commissure, either depress the
parts or draw them from the median line.
The constant and habitual exercise of either
of these sets of muscles leaves corresponding
permanent folds in the skin, which are in-
dicative of the habitual feelings and passions
of the individual.

The integuments of the face.— The skin of
the face is, with the exception of some parts,
remarkable for its tenuity, for its abundant
supply of vessels, nerves, and follicles ; for
the growth of hair, which covers some parts
of it; and for its attachment to the subjacent
muscles. The vascularity of the skin in some
parts is even beautiful, tinting the cheek and
lips, as in the act of blushing, assisting in the
expression of the feelings and passions. The
subcutaneous cellular tissue is, in general, very
dense in this region, and is mingled with more
or less fat, except on the eyelids, where it is
loose, delicate, and quite destitute of adipose
tissue. Generally speaking, the skin of the
face is more adherent, and the subjacent cel-
lular tissue is more dense and less fatty, along
the median line than at the lateral parts ; the
nose and lips offer examples of this fact. At
the sides the cellular tissue is looser below,
near the base of the jaw, than higher up on
the cheeks. Most of the muscles are more or
less surrounded with fat, which, however, par-
ticularly abounds on the cheeks and between
the masseter and buccinator muscles.

Vessels of the face. — The arteries are de-
rived chiefly from the external carotid, viz.
1. the external maxillary or the facial artery,
and its branches; 2. branches from the tem-
poral, particularly the transverse facial artery ;
3. branches from the internal maxillary, more
particularly the infra-orbitar, the buccal, and
the superior and inferior dental arteries; 4.
some arteries which emerge from the orbit and
are derived from the ophthalmic branch of the
internal carotid. These vessels communicate
very freely with each other, and form with
their accompanying veins an intricate vascular
network over the face. See CAROTID AR-
TERY.

The veins are principally branches of the
external jugular, viz. 1 . the facial vein with
its branches, which correspond generally to the
trunk and branches of the facial artery, except
that the facial vein is rather more superficial

Q2

228

FACE.

and further from the median line than the
artery; 2. the transverse facial vein and some
other small branches of the temporal; 3. veins
corresponding to the branches of the internal
maxillary artery already mentioned ; and,
lastly, some veins about the nose and brow,
which are connected with the ophthalmic vein
within the orbit. Both arteries and veins are
imbedded in the adipose tissue, and are often
remarkably tortuous, more especially the ar-
teries, in old persons. Their trunks and
branches open in a direction towards the me-
dian line, particularly at the upper part of the
face.

The lymphatics are much more numerous
than those of the cranium, and follow prin-
cipally the course of the bloodvessels, and
terminate in the submaxillary and parotid lym-
phatic ganglions ; in their course they traverse
some ganglions, which are situated on the buc-
cinator.

The superficial lymphatics arise from all
parts of the face, and, accompanying the su-
perficial vessels, end in the submaxillary gan-
glions; some of them traverse the smaller
buccal ganglions.

The deep lymphatics are situated in the zy-
gomatic and pterygo-maxillary fossae ; they
also accompany the bloodvessels, and ter-
minate in the deep parotid and submaxillary
ganglions.

The lymphatic ganglions of the face are prin-
cipally situated along the base of the jaw, and
are termed the submaxillary ganglions. Others
are placed on the jaw and buccinator, in front
of the masseter (the buccal ganglions), and
follow the facial vessels. Some" lymphatic
ganglions are situated underneath the zygoma
(the zygomatic ganglions) ; and others, more
numerous, are placed upon, within, or under-
neath the parotid gland, and are termed the
parotid ganglions. The deep lymphatics of
the orbits, nose, and mouth, will be described
with those cavities.

The nerves of the face are derived from the
three divisions of the fifth and from the portio
dura of the seventh cerebral nerves. The
branches from the fifth emerge on the face,
1. from the orbit; these come from the oph-
thalmic or first division of the fifth, and are
the frontal, the supra-trochlear, the infra-
trochlear, and the lachrymal : 2. from the
infra-orbitar foramen escape the infra-orbitar
nerve, from the second division of the fifth or
superior maxillary, and from the same source,
emerging from underneath the ramus of the
jaw, the buccal nerves : 8. from the mental
foramen emerge branches of the inferior den-
tal nerve, derived from the third division of
the fifth or the inferior maxillary ; and from
the same source, piercing the masseter, the
masseteric nerves. The portio dura, after turn-
ing over the posterior border of the lower jaw,
forms a plexus (the pes anserinus) within the
parotid gland, and divides into a great num-
ber of branches, which are distributed on the
face, and which have received various names
corresponding to the regions where they run.
The branches of the fifth nerve which are dis-

tributed to the face principally supply the in-
teguments, and those of the portio dura the
muscles. Some filaments, however, of the
fifth, such as the buccal branch, derived from
the ganglionous portion, supply muscles ; and,
on the other hand, some cutaneous twigs are
sent from the portio dura of the seventh to the
commissure of the .lips. Both nerves freely
anastomose with each other on the face. For a
more particular account of these nerves and of
their functions, see FIFTH PAIR OF NERVES,
SEVENTH PAIR OF CEREBRAL NERVES, and
PHYSIOGNOMY.

Abnormal conditions of the soft parts of the
face. — The muscles of the face offer nothing
very remarkable in their abnormal conditions ;
like others, they become much developed by
constant exercise, and on the other hand, when
paralytic, they waste and lose both their colour
and consistence; their fibres have been ob-
served occasionally to have degenerated into a
fatty substance, and the trichina spiralis has
also been found among them as among those
of other voluntary muscles.

The bloodvessels of the face are subject to no
anomalies in their course which call for notice
in this place. It may be remarked, however,
that they vary in size in different individuals,
and are sometimes superficially and sometimes
more deeply situated among the soft parts
around ; their tortuosity in old age has already
been adverted to.

Vascular ncevi are not unfrequently found on
the face, in some cases deeply situated within
the cavities or underneath the bones; in others,
and more commonly, they lie superficially in
the skin and subcutaneous tissues. They occur
of the venous, arterial, or mixed kinds. The
first sometimes attain a considerable magni-
tude, as I have witnessed in the case of an old
woman, in whom such a naevus grew on one
cheek and lip, and exceeded in size the whole
face. Such swellings are easily compressed,
and often produce no other inconvenience than
that of their deformity and weight. The arte-
rial naevus, however, and more especially when
deeply seated, is sometimes a formidable dis-
ease, which may involve all the surrounding
structures and ultimately prove fatal. The cu-
taneous capillaries of the cheeks, and about the
tip and alae of the nose, often become enlarged
and varicose, presenting a peculiar appearance,
which is not uncommon in hard drinkers.

The lymphatic glands of the face are particu-
larly liable to inflammation, enlargement, and
suppuration. In scrofula they often form im-
mense swellings along the base of the jaw and
about the parotid gland, sometimes remaining
permanently enlarged, and sometimes suppura-
ting and terminating in abscesses difficult to
heal.

The nerves of the face are liable to be pressed
upon and irritated by the enlarged glands and
by the tumours in this part of the body. The
face is also subject to a most distressing com-
plaint, termed tic doulouroux, which may arise
spontaneously or from injury, and which ap-
pears to affect particularly, if not exclusively,
the branches of the fifth pair of nerves, and

FASCIA.

229

more especially the iufra-orbitar. Neuralgia
of the lower part of the face seems, however, in
some instances to follow the course of those
branches of the cervical plexus which proceed
toward this region. Division of the nerves,
though it sometimes checks, seldom cures this
painful affection, for the divided nerves spee-
dily reunite, and the complaint returns ; and
this takes place even after a portion of the
nerve has been removed. Spasmodic affections
of the face are connected with the branches of
the portio dura : both nerves are of course sub-
ject to palsy.

The cellular tissue of the face is abundant,
vascular, mingled generally with more or less
fat, and in some places, as on the eyelids, is so
lax as to be peculiarly liable to infiltration
with fluids. Sometimes it becomes emphyse-
matous, in cases of wounds of the frontal sinuses
and larynx. It is easily affected by erysipelas,
and is the common seat of abscesses, which,
however, as there is no fascia to confine the
matter, rarely attain any considerable size, but
soon make their way towards the surface of the
skin. When, indeed, the pus forms on the
forehead between the muscles and the pericra-
nium, or beneath the fascia covering the parotid
gland, or beneath that investing the masseter
and posterior part of the buccinator muscles,
the matter being more confined is longer in
arriving at the surface, and is productive of
more pain than in the former instance. En-
cysted tumours are not unfrequently formed in
this structure of the face.

The skin of the face, from its vascularity and
the almost homogeneous mass which it forms
with the subjacent tissues, readily unites after
incised wounds, and hence the success which
has attended the attempts at reparation of some
parts of this region, such as the nose, cheek,
and lips ; the extensibility of the skin also
favours such operations. Punctured and con-
tused wounds of the face are apt to produce
erysipelas when they affect those parts where
the cellular tissue is most dense, as on the nose
and the prominence of the cheek. Abscesses
are the more common result where the cellular
tissue is looser. The skin of the face becomes
swollen and thickened in some complaints
which attack it, such as scrofula, which produ-
ces enlargement of the lips and nose, and ele-
phantiasis, cancer, and a few other diseases
which affect it more permanently. It is sub-
ject also to freckles, stains, and discolorations
of various kinds, enlargement, inflammation,
and induration of its follicles; to a variety of
cutaneous eruptions ; to ulcerations from scro-
fula, scirrhus, lupus, &c. which frequently
make great ravages not only in the soft parts of
the face, but even in the bones ; to tubercles,
warts, tumours, and anomalous growths of
various kinds ; and finally to boils. Its vas-
cularity renders it more liable than in other
parts of the body to receive the impression of
small-pox pustules. Like the bones, the soft
parts of the face are subject to congenital mal-
formation. 1. Its apertures may be closed
more or less firmly ; this happens with the eye-
lids, nostrils, and lips. 2. There may be de-

fects of growth, as fissures in the lips, or hare-
lip, which may be single or double, and exist
alone or in combination with fissures of the
palate. The fissure may vary in depth, some-
times, in the upper lip, extending into one of
the nostrils, and at others only affecting the
border of the lip. Congenital cleft of the lower
lip is very rare, and is never combined with
fissure of the bone. The nose is sometimes
fissured, presenting no cartilaginous septum,
and but one large orifice or nostril. Occasion-
ally a congenital fissure has been observed in
the cheek. The abnormal conditions of the
teeth, the orbits and their contents, of the
lachrymal apparatus, and of the cavities of the
nose and mouth, will be found under the seve-
ral articles on these subjects.

For the BIBLIOGRAPHY of thia article, tsee
ANATOMY (INTRODUCTION).

(R. Partridge.)

FASCIA, (in general anatomy,) (Binde,
sehinge Scheide, Flechsenh'dute, Germ.) This
term is applied to certain membranous expan-
sions, existing in various regions of the body,
and forming coverings to particular parts.
These expansions are composed either of cellu-
lar tissue, more or less condensed, or of fibrous
tissue, the former being the cellular fascia, the
latter the aponeuroses or aponeurotic fascia.
The structure and connexions of a considerable
number of the fasciae are highly interesting, as
well with reference to correct diagnosis and
prognosis in surgical disease, as in regard to
the mode of proceeding in various operations.

1. Cellular fascia. — These are lamellae of
cellular membrane of variable density, some-
times loaded with fat, at other times totally
devoid of it, The best example of this form of
fascia is the layer of cellular membrane which
is immediately subjacent to the subcutaneous
cellular tissue all over the body, and in most
places so intimately connected with it as to be
inseparable ; these in fact form but one mem-
brane, which, although essentially the same
everywhere, yet exhibits characters peculiar
almost to each region of the body; it is gene-
rally known under the name of the superficial
J'ascia. Although this fascia is universal, there
are, nevertheless, certain regions where, from
its greater importance, it has been more care-
fully examined than in others, and to which we
may best refer in order to investigate its pecu-
liar characters. Of these regions those of the
abdomen and the neck stand pre-eminent; here
this fascia constitutes a distinct membraniform
expansion, and the principal variety it pre-
sents in different subjects is as regards the
greater or less quantity of fat deposited in it.
Where a tendinous or fibrous expansion does
not lie immediately under it, this fascia sends
processes from its deep surface to invest the
subjacent muscles and other parts; this is very
manifest in the case of the fascia of the neck ;
and in general it may be stated that the super-
ficial fascia has a more or less intimate connec-
tion with the proper cellular covering of sub-
jacent organs, whether muscles or tendons.

230

FASCIA.

The arrangement to which we allude in the
fascia of the neck may be satisfactorily traced
from the median line on the anterior surface of
the neck, proceeding outwards on each side.
On the median line the fasciae of opposite sides
are intimately united so as to form a dense line,
called by some anatomists linea alba cervicalis;
thence on each side the fascia divides into
laminae, investing the sterno-hyoid and thyroid
muscles, the carotid artery and jugular vein,
the sterno-mastoid, and other muscles; and
thus anatomists come to describe a superficial
and a deep layer of the cervical fascia; the
former being continuous with the superficial
fascia covering the muscles on the anterior
part of the thorax, the latter, intimately con-
nected with all the deep-seated structures in
the neck, may be traced outwards behind the
sterno-mastoid muscle, along the posterior edge
of which it becomes again united with the su-
perficial layer ; the fascia, thus re-constructed,
passes through the triangular space which in-
tervenes between the muscle last-named and
the trapezius, and may be traced over that
muscle to become continuous with the superfi-
cial fascia on the back. It is the deep layer
of this fascia which was described by Godman
of Philadelphia* as passing downwards behind
the sternum to be continuous with the fibrous
pericardium. This description has been sub-
sequently confirmed by more than one anato-
mist in France, although denied by Cru-
veilhier, and in this country by Sir Astley
Cooper, f who has described it in the same
manner, apparently without being acquainted
with the previously recorded statements of the
anatomists above referred to ; I may add that
I have myself in many instances proved the
accuracy of Godman's description. The cer-
vical fascia is continuous superiorly with the
superficial fascia on the face; and inferiorly,
besides tracing it into the pectoral region, we
can follow it over the shoulder into the arm.
The cervical fascia, in a great part of its extent,
is not, as the superficial fascia elsewhere, in
intimate connexion with the subcutaneous cel-
lular tissue, but is separated from it on each
side of the neck by the fibres of the platysma
myoides. From this brief account of the cervi-
cal fascia, (we refer for the more particular
description to the article on the surgical ana-
tomy of the NECK,) we learn one characteristic
of the superficial fascia, namely, its continuity
all over the body.

The superficial fascia of the abdomen has
attracted the attention of anatomists and sur-
geons from its connexion with all herniary
tumours in that region. In its arrangement it is
much less complex than the cervical fascia,
being a uniform membranous expansion spread
over the superficial muscular and aponeurotic
structures of the abomen, continuous on either
side and posteriorly with the superficial fascia
of the lumbar regions, and inferiorly with that
of the inferior extremities. See the description
of it in the article ABDOMEN.

* Anatomical Investigations, Philadelph. 1824.
t On the thymus gland.

The superficial fascia of the limbs is com-
pletely confounded with the subcutaneous cel-
lular tissue, and wants that condensation by
which on the trunk generally, but particularly
in the neck and abdomen, it is distinguished.

There can be no doubt that the superficial
fascia is no more than condensed cellular mem-
brane, and its variety of appearance in different
regions depends in a great measure upon pecu-
liarities in the motions and arrangement of the
parts contained in those regions, e.g. wherever
the muscles of a part are in very frequent ac-
tion, and at the same time the fascia is com-
pressed between the integument and the mus-
cles, it suffers condensation ; this is conspicuous
in the abdomen, where there is almost incessant
muscular action in consequence of the respi-
ratory movements, and where the weight of the
viscera, thrown forwards in the erect posture,
occasions a considerable pressure upon the an-
terior and lateral portions of the abdominal
parietes. The deposition of adeps to any great
extent is unfavourable to the existence of a
distinct fascia superficial is, which is thereby, as
it were, decomposed, and hence this fascia is
not distinct from the subcutaneous cellular
tissue in those regions where, either habitually
or preternaturally, this substance is largely de-
posited.

The superficial fascia is identified with the
subcutaneous cellular membrane in the cranial
regions, a circumstance which seems attributa-
ble to the firm adhesion of the aponeurotic ex-
pansion of the occipito-frontalis muscle to the
subcutaneous tissue, and also the cutaneous
insertion of other muscles ; to a similar cause
we may ascribe the indistinctness of this fascia
in the face also, as likewise to the great depo-
sition of fat in some parts of this region. In
the pectoral region it is attenuated, and is
more intimately connected with the proper
cellular covering of the great muscles than
with the subcutaneous cellular tissue.

Where the superficial fascia has suffered
condensation to a considerable extent, and
there is a complete absence of adipose sub-
stance, it assumes an appearance which has
given rise to the designation " fibro-cellular,"
in consequence of the existence of thick, white,
and opaque bundles intersecting the membrane
in various directions; these bundles seem to
be produced by the close application of the
walls of the cells to each other, and the conse-
quent obliteration of their cavities. This, how-
ever, I believe is the nearest approach that the
superficial fascia makes to fibrous membrane ;
and I am strongly disposed to question the
accuracy of Velpeau's assertion, that it is some-
times transformed into the yellow fibrous or into
muscular tissue. The elastic abdominal ex-
pansion, described by Girard, is certainly not
a conversion of the superficial fascia, but of
the muscular aponeurosis.

Among the cellular fasciae, Velpeau* de-
scribes a layer of cellular membrane, pretty
uniform in its characters, and in some localities
of great practical importance, and gives it the

* Anat. Chiiurg. t. i. p. 42.

FAT.

231

name fascia superjicialis interna. It is in
contact with the serous membranes of the prin-
cipal cavities in the body, with those of the
abdomen, thorax, and pelvis in particular; in
the former of which it has attracted most atten-
tion under the denomination of ihejascia pro-
pria. This cellular layer lies between the
serous membrane and the fibrous layer which
lines the parietes of the cavities, as for instance
the fascia transversalis in the abdomen; and
consequently in this last cavity, when any
viscus is protruded, carrying a peritoneal sac
before it, this cellular layer uniformly forms the
immediate investment of the sac, and is there-
fore called fascia propria, a hernial covering
which every practical surgeon well knows is
often of considerable density and thickness,
and to which indeed is attributable the so-called
thickening of the sac itself.

2. Aponeuroses or aponeurotic fascia. — This
appellation should be confined to those textures
which are purely fibrous, and belong to either
the white fibrous tissue or the yellow. In man,
they belong entirely to the former class, but we
see some interesting examples among the lower
animals, where, while the same characters as to
intimate texture are preserved, they assume a
yellow colour, and exhibit most manifestly the
property of elasticity.

The greatest number of the fibrous aponeu-
roses are connected with muscular fibres, and
in fact serve as tendons to them, and are de-
scribed as such. Of these we have the best
examples in the fibrous aponeuroses of the ab-
dominal muscles, by which a considerable por-
tion of the paries of this cavity is constructed
of a resisting inelastic material, which is at the
same time under the control and regulation of
muscular fibre. These expansions are com-
posed of silvery white parallel fibres, in many
places strengthened by bundles which cross
and interlace with the fibres last named, e. g.
the intercolumnar bands at the apex of the ex-
ternal abdominal ring. It is interesting to
notice that in the larger quadrupeds, when the
weight of the viscera is imposed on these
aponeuroses, they are composed of the yellow
elastic fibrous tissue. I have also seen the
fascia lata thus converted.

A second class of these aponeuroses consists
of those which cover the soft parts in particular
regions. In general we find that where there
are many muscles covered, the aponeurosis
sends in processes by which each muscle is
separately invested, these processes being ulti-
mately inserted into the periosteum of the bone.
Thus the fascia lata of the thigh separates by
means of processes prolonged from its deep
surface, the various muscles to which it forms
an external envelope, in such a manner that, if
the muscles be carefully dissected away from a
thigh, without opening the fascia more than is
sufficient for their removal, it will appear to
form a series of channels in which the muscles
are lodged. A similar arrangement is found in
the leg and foot, and in each of the segments
of the upper extremity. The fascia lata has the
peculiarity of being in a great degree influenced
in its tension by a muscle, called from that

office, tensor vagina femoris, and the fascia
which covers the palm of the hand is likewise
governed by the palmaris longus, the connec-
tion of which, however, with the fascia seems
to have reference, not to the functions of the
fascia, but to the power of the muscle, in aid
of the other flexors of the wrist ; the fasciae of
the leg and arm too receive the terminal expan-
sion of the tendons of muscles. The strength
of these aponeurotic sheaths is proportionate to
the strength of the muscles they cover ; this is
apparent, by comparing the fasciae of the arm
and of the thigh ; the strength of the latter
greatly exceeds that of the former, and in the
thigh itself the vastus externus muscle is covered
by a portion of the fascia lata, much stronger
than those which cover the muscles on its
posterior and inner aspects.

In a third class of aponeuroses are enume-
rated simple lamellae of fibrous membrane,
which are found for the most part in connexion
with the walls of cavities : such are the fascia
transversalis, connected with the abdomen; the
fascia iliaca and pelvica, connected with the
pelvis; and the fibrous expansion lining the
thorax, which has not received a name.

The aponeurotic fasciae are most valuable in
their power of resistance, and thus efficacious
in maintaining organs in their proper situa-
tions ; that they exert a considerable degree of
compression upon the muscles is rendered
evident by the hernia of the muscular fibres
which takes place when an incision is made
into the fascia lata of the thigh ; they thus re-
gulate the combined action of muscles and
render more complete their isolated action. It
is incumbent on the surgeon to remember how
they confine purulent collections and oppose
their progress to the surface, a property which
is likewise observable in the cellular fasciae,
whose power of resistance is, however, much
less, but their elasticity much greater.

Such is a brief notice of the generalities con-
nected with the fasciae of the body : the situa-
tion, connections, and structure of many of
them are of great interest to the surgical anato-
mist, and will be found fully detailed in the
articles devoted to the surgical anatomy of
the regions. The subject is also very com-
prehensively treated in the following works,
God/nan, Anatomical Investigations, Phila-
delph. 1824 ; Velpeau, Anat. Chirurgicale, t. i.
ed. 2de ; Paillard, Description complete des
Membranes fibreuses, Par. 1827; Cruveilhier,
Anat. Descript. t. ii. Aponeurologie, Par.
1834 ; Bourgery, Anatomic de 1'homme, t. ii.
(R. B. Todd.)

FAT. (<7T£a£, 9rt/x£X»j, adeps, pinguedo;
Fr. graisse ; Germ.Fett; Itzl.grasso.) Under
this term we include a variety of animal pro-
ducts which bear a general resemblance to
each other, and to a series of corresponding
substances in the vegetable kingdom ; the fats
of animals being, like the vegetable oils, ternary
compounds of carbon, hydrogen, and oxygen,
and not, apparently in any instance, containing
nitrogen, except as an adventitious or acciden"
tal ingredient.

232

FAT.

Fat is a deposition in the cellular membrane
of certain parts of the body, especially under
the skin, in the omentum, in the region of the
kidneys, and within the cylindrical bones : it
also occurs here and there among the muscles,
and sometimes is accumulated to an extent so
unnatural as to form a species of disease. In
birds it is chiefly seated immediately below the
skin, and in water-fowl it is largely secreted by
the glands of the rump : in the whale and other
warm-blooded inhabitants of the deep, it is
chiefly contained in the head and jaw-bones,
and abundantly interposed between the skin and
the flesh ; in fish it abounds in the liver, as in
the shark, cod, and ling, or is distributed over
the whole body, as in the pilchard, herring, and
sprat.

Various opinions have been entertained re-
specting the formation of fat, and its insolu-
bility in water has led to the idea of its produc-
tion in the places in which it occurs ; but as it
is found in the blood and in some other of the
fluids of the body, it is probably partly received
with the food, and partly formed by the process
of secretion. Its remarkable absorption in cer-
tain cases of disease of the chylopoietic viscera,
and of deficiency of proper food, seems to point
it out as a source of nutriment of which the ani-
mal economy may avail itself on emergency ;
and accordingly in cases of emaciation or atro-
phy, it is the first substance which disappears. It
varies in consistency and characters in the diffe-
rent tribes of animals, and in the greater num-
ber of amphibia and fishes it is usually liquid at
ordinary temperatures. (See ADIPOSETISSUE.)

The general chemical characters of fat have
been long known, as well as its important pro-
perty of saponification by means of the alkalis ;
but the real nature of the changes which it un-
dergoes in this process, and the essential dis-
tinctive characters of its varieties, were first
satisfactorily investigated by Chevreul,* whose
essay upon the subject has been justly cited as
a model of chemical research. It is chiefly
from this source, and from the abstract of its
contents given by Berzelius,f that we have
taken the following details.

All the varieties of fat are resolvable into
mixtures of stearin and elain, (from <rr£x%, suet,
and ehcuov, oil,) that is, into a solid and
liquid ; but there are peculiar differences be-
longing to these products in each individual
species, which sometimes seem to depend upon
very trifling causes, and at others to be con-
nected with distinct ultimate composition.

There are two modes by which the stearin and
elain of fat may be separated : the one consists
in subjecting it to pressure, (having previously
softened it by heat, if necessary;) and the other,
by the action of boiling alcohol, which, on
cooling, deposits the stearin, and retains the
elain in solution; the latter separates on the
addition of water, still however retaining a
little stearin ; they may be ultimately separated
by digestion in cold alcohol, sp. gr. .835, which

* Recherches chimiques sur les corps gras d'ori-
gine animate. Paris, 1823.

t Lehrbuch der Chemie. B. 3 and 4. Dresden,
1827.

takes up the elain, and leaves it after careful
distillation ; the stearin remains undissolved.

Fat may be separated from its associated
cellular texture, by cutting it into small pieces
and melting it in boiling water; it collects upon
the surface, and when cold is removed, and
again fused in a water-bath, and strained
through fine cambric. Many varieties of fat,
when dissolved in boiling alcohol and precipi-
tated by water, leave a peculiar and slightly
acid and saline extract in solution, apparently
derived from the enveloping membranes.

1. The softer kinds of fat are termed lard, of
which hog's-lard furnishes a good example: it is
white, fusible at a temperature between 75°
and 85°, and of a specific gravity = about 0.938.
When cooled to 32°, and pressed between folds
of bibulous paper, it gives out 62 per cent, of
colourless elain, which remains fluid at very
low temperatures, has a sp. gr. =.915, and is
soluble in less than its weight of boiling alco-
hol, the solution becoming turbid when cooled
to about 140°. The residuary stearin is ino-
dorous, hard, and granular: when fused, it
remains liquid at the temperature of 100°, but,
on congealing, it rises to 130°, and assumes a
crystalline appearance.

When hog's-lard becomes rancid, a pecu-
liar volatile acid forms in it, which has not been
examined. 100 parts of hog's-lard yield, when
saponified, 94.65 margaric and oleic acid,
which when fused concrete at 150°; and 9. of
glycerine. According to Chevreul's analysis, the
ultimate elements of hog's-lard are —

Carbon 79.098

Hydrogen 11. 146

Oxygen 9.756

100.000

2. Human fat is another species of lard ;
but it differs in different parts of the body. The
fat from the kidney, when melted, is yellow,
inodorous, begins to concrete at 77°, and is
solid at about 60°. It requires 40 parts of
boiling alcohol of 0.841 for solution, and this
deposits stearin as it cools, which, when puri-
fied by pressure between folds of filtering
paper at 77°, is colourless, fusible at 122°, and
may then be cooled down to 105°, before it
concretes; in the act of concreting its tempera-
ture rises to 120°, and it becomes crystalline,
and soluble in about four parts of boiling alco-
hol, the greater part being deposited in acicular
crystals as the solution cools. The elain of
human fat, obtained by the action of hot water
upon the paper by which it had been absorbed,
is colourless, remains fluid at 40°, and con-
cretes at a lower temperature. Its specific
gravity at 60° is .913; it is inodorous, and has
a sweetish taste. It is soluble in less than its
weight of boiling alcohol, and the solution be-
comes turbid when cooled to about 62°. 100
parts of human fat yield, when saponified, about
96 of margaric and oleic acids fusible at about
90°, and from 9 to 10 of glycerin.

According to Chevreul, human fat aud its
elain are composed as follows : —

FAT.

233

FAT. ELAIN.

Carbon........ 79.000 78.566

Hydrogen 11.416 11.447

Oxygen 9.584 9.Q87

100.000 100.000

3. The fat of beef when melted begins to
concrete at 100°: it requires for solution 40
parts of boiling alcohol, and contains about
three-fourths its weight of stearin, which is
obtained by stirring the melted fat whilst it is
concreting, and then pressing it in woollen
cloths at a temperature of about 95°, by which
the elain is squeezed out, together with a por-
tion of stearin, which is deposited at a lower
temperature, for the elain does not congeal at
32°. The stearin is white, granularly crystal-
line, fusible at 112°, and may be cooled to 100°
before it congeals, when its temperature rises to
112°. It looks and burns like wax. 100 parts
of alcohol dissolve 15 of this stearin : when
saponified, it yields 0.95 of fat acids, which
fuse at 130°. The elain of beef fat is colour-
less and almost inodorous, and soluble in less
than its weight of boiling alcohol. Candles
made of the stearin of this fat, with a small
addition of wax to destroy its brittle and crys-
talline texture, are little inferior to wax candles.

4. Neat's foot oil is obtained by boiling the
lower ends of the shin-bones of the ox, after the
removal of the hair and hoofs, in water. This
oil remains fluid below 32°, and after the sepa-
ration of the stearin, is used for greasing turret-
clocks, which are often so exposed to cold as to
freeze other oils.

5. Goafs fat is characterized by its peculiar
colour, which seems to depend upon the pre-
sence of a distinct fatty matter, which, in the
separation of the stearin and elain, is asso-
ciated with the latter, and which Chevreul has
called hircin. When the elain is saponified,
a liquid volatile acid is formed, which may be
separated as follows : four parts of the fat are
made into soap with one of hydrate of potassa
dissolved in four of water : the soap is after-
wards diluted, and decomposed by phosphoric
or tartaric acid, by which the fat acids are sepa-
rated : these are distilled with water, taking
care that the contents of the retort do not boil
over : the distilled liquid is saturated with
hydrate of baryta, evaporated to dryness, and
decomposed by distillation with sulphuric acid
diluted with its weight of water : the acid is
separated in the form of a colourless volatile
oil which floats upon the distilled liquid ;
Chevreul terms it hircic acid: it congeals at
32°: it has the odour of the goat, blended
with that of acetic acid ; it reddens litmus,
dissolves difficultly in water, and readily in
alcohol : it forms distinct salts with the bases :
the salt of ammonia has a strong hircine
odour : that of potassa is deliquescent, and that
of baryta difficultly soluble in water.

6. Mutton fat is whiter than that of beef,
and acquires a peculiar odour by exposure to
air ; when melted it begins to concrete at about
100°. It requires 44 parts of boiling alcohol
for solution. Its stearin, when fused, begins

to congeal at 100°, and its temperature rises on
solidification to 113°. 100 parts of alcohol
dissolve 16 of it. Its elain is colourless,
slightly odorous, sp. gr. 0.913, and 80 parts of
it are soluble in 100 of boiling alcohol. When
saponified, it yields a very small quantity of
hircic acid. This species of fat, together with
its stearin and elain, are composed as fol-
lows : —

FAT. STEARIN. ELAIN.

Carbon 78.996 78.776 79.354

Hydrogen ».l 1.700 11.770 11.090
Oxygen .... 9.304 9.454 9.556

100.000 100.000 100.000

7. Whale oil, or train oil, (from whale blub-
ber,) sp. gr. .927, when cooled to 32°, deposits
stearin ; the filtered oil is then soluble in 0.82
of boiling alcohol. Aided by heat it dissolves
arsenious acid, oxide of copper, and oxide of
lead ; sulphuric and muriatic acids render the
latter combination turbid, nitric acid tinges it
dark brown with effervescence ; and it is coa-
gulated by potassa and soda. This oil is easily
saponified when mixed with 0.6 its weight of
hydrated potassa, and five parts of water ; the
soap is brown, soluble in water, and when de-
composed by tartaric acid and the sour liquid
distilled, it yields traces of phocenic acid, also
glycerine, and oleic and margaric, but no
stearic acid : these acids are accompanied by a
greasy substance which has the odour of the
oil. The stearic portion of train oil, when
freed from adhering elain by washing with
weak alcohol, concretes, after having been fused,
at a temperature between 70° and 80°; it is
soluble in 1.8 parts of boiling alcohol, and is
deposited in crystals as it cools, leaving a dark
thick mother-liquor. When saponified, 100
parts yield 85 of margaric and oleic acids, 4 of
a brown substance infusible at 212°, and per-
fectly soluble in boiling alcohol, 7 of bitterish
glycerine, and traces of phocenic acid.

8. Spermaceti oil, the produce of the sper-
maceti whale,* is lodged in the cartilaginous
cells of a bony cavity on the upper part of the
head ; as it cools, it deposits its peculiar stearic
portion in the form of spermaceti; this sub-
stance is further separated by pressure in wool-
len bags from the oil, and is then washed with
a weak solution of caustic potassa, melted in
boiling water, and strained; it is commonly
cast into oblong blocks, and if the interior
liquid portion is drawn off when the exterior
has concreted, the cavity exhibits upon its sur-
faces a beautiful crystalline texture. Sperma-
ceti, as it occurs in commerce, is in semi-trans-
parent brittle masses of a foliated fracture, and
soapy to the touch ; it has a slight odour and a
greasy taste, and when long kept becomes yel-
lowish and rancid. Its specific gravity is .943 ;
it fuses at about 114°. 100 parts of boiling
alcohol, sp.gr. .823, dissolve 3.5 spermaceti,
and about 0.9 is deposited on cooling. Warm
ether dissolves it so copiously, that the solution
concretes on cooling; by the aid of heat, it

* Physeter macroccphalus, or Cachalot.

234

FAT.

dissolves in the fat and volatile oils, and is in
part deposited as the solution cools. Alcohol
always extracts a small portion of oil from the
spermaceti of commerce ; as the boiling alco-
holic solution cools, it deposits the purified
spermaceti in white crystalline scales, and in
this state, Chevreul terms it cetine. Cetine
does not fuse under 120°; it forms, on cooling,
a lamellar, shining, inodorous, and insipid
mass, which is volatile at high temperatures,
and may be distilled without decomposition.
It burns with a brilliant white flame, and dis-
solves in about four parts of absolute alcohol ;
it is very difficultly saponified ; digested for
several days at a temperature between 120° and
1 90°, with its weight of caustic potassa and two
parts of water, it yields margarate and oleate of
potassa, and a peculiar fatty matter, which
Chevreul calls ethal* and which amounts to
about 40 per cent, of the cetine used. To ob-
tain it in an insulated state the results of
the saponifi cation of cetine are decomposed by
tartaric acid, which separates the margaric and
oleic acid, together with the ethal ; the fat
acids are saturated with hydrate of baryta, and
the resulting mixture well washed with water
to separate all excess of base ; it is then well
dried, and digested in cold alcohol or ether,
which takes up the ethal and leaves the barytic
salts ; the former is then obtained by evapora-
tion of the solvent. Ethal is a solid, transpa-
rent, crystalline, fatty matter, without smell or
taste; when melted alone it congeals at 120°
into a crystalline cake ; it is so volatile that it
passes over in vapour when distilled with water.
It burns like wax, and is soluble in all propor-
tions in pure alcohol at a temperature below
140°. It readily unites by fusion with fat and
the fat acids, and when pure is not acted upon
by a solution of caustic potassa; but if mixed
with a little soap it then forms a flexible yel-
lowish compound, fusible at about 145°, and
yielding an emulsive hydrate with boiling
•water.

The ultimate composition of train oil, sper-
maceti oil, spermaceti, cetine, and ethal, are
shewn in the following tables : —

TRAIN OIL. SPERMACETI OIL.

Berard. Ure.

Carbon 76.1 79.0

Hydrogen.. 12.4 10.5

Oxygen.... 11.5 10.5

100.0 100.0

SPERMACETI. CETINE.

Berard. Chevreul.

Carbon 79.5 81.660

Hydrogen.. 11.6 12.862

Oxygen.... 8.9 5.478

100.0 100.000

* From the first syllables of the words ether and
alcohol, in consequence of a resemblance in ultimate
composition to those liquids.

ETHAt. (" Chevreul.)

Atoms.

Carbon., 17

Equivalents.
102

Theory.

79.69

Experiment.
79.766

Hydrogen 18

18

14.06

13.945

Oxygen. . 1

8

6.25

6.289

1 128 100.00 100.000

9. Phocenine is a peculiar fatty substance
contained in the oil of certain species of por-
poise (Delphinus phocena and globiceps).
When this oil is saponified, it yields margaric
and oleic acid and cetine, and a peculiar vola-
tile acid obtained by a process similar to that
for separating hircic acid, and which has been
termed phocenic acid* It is a thin, colourless,
strong-smelling oil, of a peculiar acrid, acid,
and aromatic taste; its specific gravity is .932 ;
it does not congeal when cooled down to 14°.
Its boiling point is above 212°. In this state
it is an hydrate, containing 9 per cent, of water,
from which it has not been freed. It is solu-
ble in all proportions in pure alcohol.

The neutral salts of this acid (phocenates)
are inodorous, but any free acid, even the car-
bonic, in a gentle heat, evolves the odour of the
phocenic acid. Heated in the air they exhale
an aromatic odour, dependent upon the forma-
tion of a peculiar product. By dry distillation
they blacken, evolve olefiant gas and carbonic
acid, and a thin, odorous, yellow oil, insoluble
in potassa. The phocenates of potassa, soda,
and ammonia, are deliquescent ; the phocenate
of baryta forms efflorescent prismatic crystals ;
and that of lime, small acicular prisms. The
neutral phocenate of lead, evaporated in vacuo,
yields flexible lamellar crystals, which are
fusible and easily become basic when heated ;
the subphocenate of lead is difficultly soluble
and crystallisable, and decomposed by the car-
bonic acid of the air.

According to Chevreul, the anhydrous pho-
cenic acid (as existing in its anhydrous salts)
consists of

Experiment.
65.00

Atoms. Equivalents. Theory.

Carbon.. 10 60 65.93

Hydrogen 7 7 7.69 825

Oxygen.. 3 24 26.38 26.75

91 100.00 100.00

And the oily hydrated acid is a compound of
1 atom of dry acid and 1 atom of water, or
91 4- 9 = 100.

10. The fat of birds has been but little exa-
mined ; Chevreul states that the fat of geese
concretes after fusion at about 80° into a gra-
nular mass of the consistency of butter. Ac-
cording to Braconnot it yields by pressure at
32°, 0.68 of yellowish elain, having the odour
and taste peculiar to this kind of fat, and 0.32
of stearin, fusible at 110°, and soluble in rather
more than three parts of anhydrous alcohol.
When saponified, it yields margaric and oleic
acid and glycerine.

* The same acid is contained, according to
Chevreul, in the ripe berries of the Viburnum opulus.

FEMORAL ARTERY.

235

The fat of the duck and the turkey nearly
resembles the above.

11. Among insects, peculiar kinds of fat
have been obtained from ants, and from the
cochineal insect. The latter has been examined
by Pelletier and Caventou. (Ann. de Ch. et
Phys. viii. 271.) It is obtained by digesting
bruised cochineal in ether, evaporating and re-
dissolving the residue in alcohol, till it remains
upon evaporation in the form of colourless
pearly scales, insipid and inodorous, and fusible
at 104°.

12. Under the term adipocere, we have else-
where described a species of fatty matter which
appears to result from the slow decomposition
of fibrine; and in some diseased states of the
body, a large proportion of the flesh occasion-
ally puts on the appearance of fat. In the
former case, it has been supposed that the pro-
duct is the fat originally existing in the body,
which, during the putrefaction of the other
parts, has become acidified, that is, converted
into margaric, stearic, and oleic acids; and
that these acids are more or less saturated by
the ammonia which is at the same time gene-
rated, and by small quantities of lime and
magnesia resulting from the decomposition of
certain salts of those earths pre-existing in the
animal matter. This view of the nature of adi-
pocere appears so far correct ; but the quantity
of the altered fatty matter which was found in
the cases alluded to, and in others where heaps
of refuse flesh have been exposed to humid pu-
trefaction, is sometimes such as to render it
highly probable that a portion of the fatty
matter is an actual product of the decay, and
not merely an educt or residue.

In regard to the apparent morbid conver-
sion of muscle into fat in the living body,
Berzelius observes that, because the muscles
become white, it has been assumed that they
are actually converted into fat, but that the
appearance depends solely upon the absence
of red blood, for the muscles under such
circumstances do not lose their power of mo-
tion. The truth is that, in these cases, the
accumulation of fat goes on to such an extent
in the interstitial cellular membrane of the
muscular fibre, as gradually to occasion its
almost entire absorption, and such of the mus-
cles as undergo this change gradually lose
their contractile powers. Two mutton-chops,
which have undergone this change, and in
which the altered muscle and the ordinary ex-
ternal layer of adipose membrane are quite dis-
tinct, are preserved in the Museum of the
College of Surgeons, and there is a printed
pamphlet giving an account of the symptoms
under which the sheep laboured. What may
be the chemical peculiarities of the fat depo-
sited among the fibres, as compared with the
ordinary fat, has not been ascertained.

The above is an enumeration of such of the
varieties of animal fat as have been chemically
examined. In their general characters they
closely resemble the corresponding compounds
of the vegetable kingdom ; and, with the excep-
tions specified, the process of saponification
effects upon them very similar changes : they

are also similarly acted on by the acids. Some
of them seem to afford distinct products when
subjected to destructive distillation, and during
the decomposition of whale oil for the produc-
tion of carburetted hydrogen for the purposes
of gas illumination, a variety of binary com-
pounds of hydrogen and carbon, with some
other products, are obtained, the nature of
which has been ably investigated by Professor
Faraday.*

( W. T. Erande.)

FEMORAL ARTERY (arteria cruralis;
Germ, die Schenkelarterie). The femoral ar-
tery is the main channel through which the
lower extremity is supplied with blood : in an
extended sense it might, with propriety, be
understood to comprehend so much of the
artery of the extremity as is contained within,
the thigh, intermediate to those of the abdo-
men and the leg; but the variety in the situ-
ation and relations of that vessel in different
stages of its course is so great that it has been
distinguished into two, the proper femoral
and the popliteal ; the former appellation being
applied to so much of the vessel as is situate
in the superior part of the limb, and the latter
to that portion which is contained in the lower,
in the popliteal region. The comparative ex-
tent of the two divisions of the artery differs
considerably, the femoral predominating much
in this respect, and occupying two-thirds of
the thigh, while the popliteal occupies but one;
hence the particular extent of each may be
exactly defined by dividing the thigh, longi-
tudinally, into three equal parts, of which the
two superior will appertain to the former, and
the inferior to the latter.

The proper femoral artery, then, engages
the two superior thirds of the main artery of
the thigh, continued from the external iliac
artery above, and into the popliteal below. It
emerges from beneath Poupart's ligament into
the thigh, external to the femoral vein, and on
the outside of the ilio-pectineal eminence of
the os innominatum, and it passes into the
popliteal region below through an aperture cir-
cumscribed by the tendons of the adductor
magnus and vastus internus muscles. Its
course is oblique from above downward, and
from before backward, corresponding to a line
reaching from a point midway between the
anterior superior spinous process of the ilium,
and the symphysis pubis upon the front of the
limb above, to another midway between the
two condyles of the femur, on the posterior
aspect of the bone below. Its mean direction
is straight, or nearly so, corresponding to the
line which has been mentioned, or, according
to Harrison,f to a line drawn from the centre
of Poupart's ligament to the inner edge of the
patella; but its course is, for the most part,
more or less serpentine, the vessel forming as
it descends curvatures directed inward and
outward. The presence and degree of these
curvatures, however, are influenced very much

* Phil. Trans. 1825.

t Surgical Anatomy of the Arteries, vol. ii.
p. 137.

236

FEMORAL ARTERY.

by the state of the vessel and by the position of
the limb ; when the artery is empty, they are
less marked than when it is full ; and when
the limb is extended, they are removed ; when
flexed, they are reproduced ; while in some
subjects again, they appear to be absent, the
line of the vessel's course being almost direct.
The degree to which the artery passes back-
ward is not equally great at all parts of its
course : in its upper half, i. e. from Poupart's
ligament until it lies upon the adductor longus
muscle, the vessel inclines much more back-
ward than in the remainder, and at the same
time describes a curve concave forward, but
both the latter particulars are more remarkable
when the thigh is flexed, and in thin subjects,
than when the limb is extended and in sub-
jects which are in good condition ; in the last
case the vessel is supported and held forward
by the deep fat of the groin situate behind it.
In its lower half the artery inclines less back-
ward, being supported by the muscles against
which it rests.

The femoral artery is also described as in-
clining inward * during its descent ; but this
statement requires correction, or at least ex-
planation. The vessel certainly does incline
inward at some parts of its course, and for the
most part it does so as it descends from the
os innominatum into the inguinal space, form-
ing thereby the curvatures which have been
mentioned ; but the general direction of it is
either slightly outward, or at the most directly
downward, not inward : the opinion that it is
inward has arisen, it is to be supposed, from
a partial view of its course, which, in conse-
quence of its serpentine direction, is likely to
mislead, and is at variance with that of the
popliteal artery, (the lower part of the same
vessel,) which is decidedly outward. In order
to be assured of the true direction of the
vessel, the writer has tested it carefully by
means of the plumb-line, and he has always
found that it inclined somewhat outward from
the perpendicular: the degree, however, to
which the proper femoral artery does so, is not
considerable, though sufficient to place the
matter beyond doubt.

It is to be borne in mind that, in determin-
ing the direction of the vessel's course, the
limb must be placed in the bearing which it
holds naturally in the erect posture, inasmuch
as an inclination to either side will influence
materially the direction of the artery: thus an
inclination of the limb inward will at once
give it the same tendency, and render it spiral,
both which conditions are removed by placing
the limb in its ordinary position.

In consequence of the course which the
vessel pursues, and of the oblique position of
the femur conjointly, the femoral and popliteal
arteries hold very different relations to the shaft
of that bone ; the former, in the first stage of
its course, being in a plane anterior to the
femur, and in the middle of the limb being
upon its inside ; while the latter is situate be-
hind the bone, and at the inferior part of the

* Boyer, Cloquct, Harrison.

popliteal region corresponds to the axis of its
shaft : hence the artery is said * to pass some-
what in a spiral manner in reference to the
thigh bone; but this is incorrect, the spiral
course being only apparent and resulting from
the combined effect of the obliquity of the
artery itself backward and outward, and of the
shaft of the femur inward and forward : that
this is so may be satisfactorily shewn by the
application of the plumb-line to the course of
the artery, upon the different aspects of the
limb ; from which it will appear that, allow-
ance being made for the serpentine deviations
already adverted to, the general course of the
vessel is, quam proximc, straight, and that it
cannot, at all with propriety, be said to be
spiral, this being not a real but an apparent
direction, the result of the circumstances which
have been mentioned.

The point at which the femoral artery com-
mences is referred by most writers to Poupart's
ligament; this method of demarcation is at-
tended with the inconvenience, that during life
the exact situation of the ligament is difficult
to determine, inasmuch as it does not run
direct from one attachment to the other, and
that in dissection its position is immediately
altered on the division of its connections with
the adjoining fascise : hence the student, not
having a fixed point of reference, is often at a
loss to distinguish between the iliac and femo-
ral arteries, and mistakes affecting the relations
of the most important branches of those vessels
are liable to be made. For those reasons it
appears to me that it would be much pre-
ferable to select some fixed and unchanging
point to which to refer the commencement of
the artery; and for this purpose I would
suggest the ilio-pectineal eminence of the os
innominatum, which, to the student at least,
if not to the practical surgeon, will afford an
unerring guide to the distinction of the one
vessel from the other; the femoral artery, at
its entrance into the thigh, being situate im-
mediately external to the inferior part of that
prominence,! with which point the middle of
the line connecting the anterior superior spi-
nous process of the ilium and the symphysis
of the pubis will also be found to correspond.
The precise situation of the vessel is referred
by some to the centre of Poupart's ligament,
or a point midway between the anterior supe-
rior spinous process of the ilium and the
spinous process of the pubes ; by others to a
point midway between the spinous process of
the ilium and the symphysis of the pubes.
With regard to this question it is to be ob-
served that the relation of the artery to the
points between which it is situate is not strictly
the same in all instances ; that in some it will
be found to correspond to the former, and in
others to the latter account; but that the latter
relation appears to prevail in so much the
greater number, that it ought to be adopted as
the rule. According to Velpeau it is distant
two inches and a quarter from the spinous pro-

* Harrison, op. cit. p. 137.

t This point will be discussed again.

FEMORAL ARTERY.

237

cess of the pubes, and from two and a half to
two and three quarters from the superior an-
terior spinous process of the ilium.

The femoral artery is attended through its
entire course by the femoral vein, the two
vessels lying in apposition and inclosed within
a fibre-cellular investment, to which the ap-
pellation femoral sheath will be applied. It
is also related to the crural nerve or its branches,
and it is contained, together with the vein, in
a canal of fascia, which will be denominated
the femoral canal.

It is necessary to dwell here, for a little,
upon the distinction between the two appel-
lations femoral canal and femoral sheath, that
a confusion of the one with the other may not
arise. The vessels have in fact, throughout
their course, two distinct sheaths, which may
be considered peculiar to them, contained the
one within the other : the external is formed
by the fascia lata in a manner to be presently
explained, and is in all respects analogous to
the canal furnished by the cervical fascia to
the carotid artery and jugular vein. This outer
sheath, which many may regard as the sheath
of the vessels, extends from Poupart's liga-
ment to the aperture by which they escape into
the popliteal region, and will, for reasons
•which will appear more fully by-and-bye, be
here called t lie femoral canal. The second or
internal sheath is situate within the former,
is of variable thickness, according to the point
at which it may be examined, being for the
most part very thin; adheres in general closely
to the vessels, in which particular it differs from
the outer one, within which they are com-
paratively free ; and not only covers, but also
separates them by a thin internal process,
which by its density and intimate adhesion to
the vessels connects them straitly to each
other; it is further not confined, as the other is,
to the vessels, while called femoral, but is
prolonged upon them into the popliteal region,
•where in like manner it invests and connects
them: to this investment the denomination
femoral sheath will be applied. A distinction
between the two structures is necessary in a
description of the relations of the femoral
artery, were it only to mark their existence,
but that which I have adopted is rendered
imperative by the use already made of the
latter appellation with reference to the anatomy
of hernia, in the history of which it is ap-
plied not to the canal as formed by the
fascia lata, but to that, through which the
femoral vessels escape from the abdomen, and
as formed by the fasciae transversalis and
iliaca; and the prolongation of the former of
these two fasciae being, in my opinion, con-
tinued into the internal and immediate in-
vestment of the vessels, it has appeared to me
justifiable to extend the signification of the
title femoral sheath, and to apply it to that
investment throughout their entire course, as
well below as above the saphenic opening of
the fascia lata; while his application of the
former appellation, femoral canal, is sanc-
tioned by Cloquet, by whom it is used in the
same sense.

Beside those which have been already
mentioned, the femoral artery has also,
during its course, the following general re-
lations : — posteriorly it corresponds in suc-
cession to the psoas magnus, the pectinalis,
the adductor brevis, adductor longus and ad-
ductor magnus muscles; anteriorly it is, in
the first part of its course, not covered by
any muscle and is comparatively superficial ;
and through the remainder and more exten-
sive portion it is covered by the sartorius.
Externally it corresponds to the psoas and
iliacus, to the sartorius, the rectus, and lastly
to the vastus internus muscles; the latter of
which is interposed between it and the inside
of the femur: internally it corresponds to
the pectinalis and the adductor longus mus-
cles ; and lastly it is overlapped by the sar-
torius.

It is contained, through its upper half, in
the inguinal region. This region is of a
triangular prismatic form, the base of the
triangle represented by it being above formed
by Poupart's ligament, or by a line connecting
the anterior superior spinous process of the
ilium and the symphysis pubis; its apex
below by the meeting of the sartorius and
the adductor longus muscles. The sides of
the prism are external and internal, inclined,
the former backward and inward, the latter
backward and outward, and meeting each
other along the internal and posterior side
of the femur; they are formed, the external
by the iliacus and psoas, the rectus, the vastus
internus and the sartorius muscles, and the
internal by the pectinalis and the adductors.
The base of the prism is in front, consisting
of the coverings of the space. During its
descent from the os innominatum into the
inguinal region, the artery generally inclines
inward, describing a curve convex out-
ward ; and hence, as it seems to me, the
entire course of the vessel has been assumed
to be inward ; but this first curve, when
present, is soon compensated by another in
the opposite direction. In its lower half the
artery is enclosed between muscles, the vastus
internus upon its outside, the adductors longus
and magnus behind it, and the sartorius in
front.

The course of the femoral artery may be
advantageously divided into three parts or
stages, to be distinguished as first, second,
and third, or as superior, middle, and inferior
thirds ; in each of which will be found such
peculiarities in the relations of the vessel as
will justify the number of subdivisions. They
may be defined with sufficient precision by
dividing the two superior thirds of the thigh
into three equal parts, and they will occupy
each, according to the stature, from three to
five inches.

The superior stage reaches from Poupart's
ligament to the point at which the artery
is first covered by the sartorius : during this,
its upper third, the vessel is not covered by
muscle, except at its termination, where it
is overlapped by the inner margin of the
sartorius : it is therefore comparatively super-

238

FEMORAL ARTERY.

ficial, and its pulsations can be felt during
life with greater or less facility according to
circumstances, to be explained. It has, how-
ever, four structures interposed between it and
the surface, and forming its coverings ; viz.
the skin, the subcutaneous cellular stratum,
the anterior wall of the femoral canal, and the
prolongation of the fascia transversalis or the
femoral sheath.

The subcutaneous cellular structure pre-
sents a remarkable difference according to the
condition of the subject or certain other cir-
cumstances. When the body is devoid of
fat or emaciated, this structure appears a thin,
condensed, dry and lamelliform stratum, con-
tinued from the abdomen downward upon the
lower extremity, and generally denominated
the superficial fascia of the thigh ; but when,
on the contrary, the body is in good condition,
and the quantity of superficial adeps is con-
siderable, the appearance of a membranous
expansion is removed, and in its stead a
thick and uniform stratum of fat is found in-
terposed between the skin and the fascia lata.
In other cases presenting a medium condition,
the stratum of fat and the membranous expan-
sion may be both observed : in such case the
former is generally superficial, and the latter
underneath; but when the accumulation of
adeps in the subcutaneous structure is more
considerable, e. g. in the healthy infant or in
many adults, particularly among females, no
trace of superficial fascia is to be found. So
much for the varieties which the subcutaneous
cellular structure presents naturally. It is
also found frequently in abnormal conditions
deserving of attention : at times it is divisible
to a greater or less extent into a succession of
expansions, having each the appearances of
fasciae and being of indeterminate number :
this disposition, which occurs not unfrequently,
and is of considerable importance in a practical
point of view, appears due to the influence
of pressure exerted by tumours, e. g. that of
hernia. Again, in anasarca the subcutaneous
structure becomes greatly increased in depth,
and loses all appearance of membrane, seeming
then a deep gelatinous stratum, consisting of
the cellular structure and the effused serum.

The depth, therefore, of the femoral artery
from the surface, and the number of coverings
which it may have in individual cases, must
be materially influenced by those several con-
ditions of the subcutaneous cellular structure
when present, and they should never be lost
sight of; else uncertainty and embarrassment
must arise in the conduct of operations. It
is further to be borne in mind that the account
of the coverings of the artery given in this
description has reference to the natural and
most simple arrangement of those structures.
The subcutaneous structure also encloses within
it the superficial vessels, nerves, and glands,
the relation of some of which to the artery
requires notice. The superficial vessels are
the saphena vein, the superficial femoral veins,
and those veins and arteries by which the
inguinal glands are supplied.

The saphena vein ascends, from the inner and

back part of the knee, along the inner and an-
terior aspects of the thigh to its upper extre-
mity, where it joins the femoral vein upon
its anterior and internal side, at the distance
of from one inch to an inch and a half below
Poupart's ligament. During its ascent the
vein passes forward and outward, and is situate
internal to the femoral artery: at the lower
extremity of the middle third of the thigh,
(the point at which the artery is about to pass
into the ham,) it is placed superficial to the
vessel, between it and the internal surface of
the limb, near to the inner, or at this part the
posterior margin of the sartorius muscle ; but
as the vein ascends, the distance between the
vessels increases, partly because of the greater
width of the thigh at its upper part, and
partly because the course of the vein describes
a curve convex inward ; and at the termination
of the latter it amounts to the width of the
femoral vein or somewhat more ; lower down
it is still greater in consequence of the curve
formed by the saphena. Hence, in operations
upon the superior part of the artery, the
saphena ought to be exempt from danger;
while at the lower part it must be very much
exposed, if the inner margin of the sartorius
be cut upon as the guide to the vessel.

The superficial femoral veins next claim
attention: they are very irregular in their
course and destination, and therefore are the
more likely to prove a source of embarrass-
ment in operation. They are smaller than the
saphena, but yet are in many cases of con-
siderable size : they present, according to the
subject, two dispositions; either they join
the saphena during its ascent at variable points
in the course of the thigh, and in such case
cross the limb and the artery obliquely from
without inward, at different heights ; or they
form one or two considerable vessels, which
ascend external to the saphena, and open into
the femoral vein in front, at the same time
with the former vessel, passing through the
superficial lamina of the fascia lata in the
same manner as it does. When there are
two such veins, the inner one is generally
situate internal to the artery, between it and
the saphena, and consequently very near to
it ; while the external one, or the vein, if
there be but one, runs upward and inward,
and crosses the artery in its upper third,
between the point at which the saphena joins
the femoral vein and that at which the artery
is overlapped by the sartorius: the last-de-
scribed vein, when present, must obviously
be much endangered in exposing the femoral
artery at this part of its course, and perhaps
is the vessel which has given rise to the idea
that the saphena itself may be encountered in
cutting upon the artery in this situation.

The superficial inguinal glands are distin-
guished into two sets, a superior and an in-
ferior : those of the former are more numerous,
and nearer to the integuments than the latter.
They are ranged immediately below Poupart's
ligament, having their longer diameter parallel
to it, and in greatest number superficial to
that part of the iliac portion of the fascia lata,

FEMORAL ARTERY.

239

which is called its cribriform portion, and
over the course of the femoral artery, across
which they are placed obliquely : they are
separated from the vessel by the superficial
lamina of the iliac portion of the fascia, and
by the prolongation of the fascia transversalis,
with the interposed cellular structure; and
they derive numerous arterial and venous
branches from the main trunks beneath : those
branches, which are given off partly by the
vessels themselves, and partly by their super-
ficial pudic, superficial epigastric, and su-
perficial anterior iliac branches, pass through
the interposed structures in order to reach
the glands ; in doing so they carry with them
sheaths from the fascia lata, which is prolonged
upon each as it escapes, and thus they become
the means of establishing that connection be-
tween the fascia in the groin and the subcu-
taneous stratum, in which the glands are
enveloped, which is considered to influence
so remarkably the course of femoral hernia.
The glands of the second set are less nu-
merous, are situate farther from Poupart's
ligament than the former, being below the
entrance of the saphena ; they are also deeper
seated, lying upon the fascia lata, and they
are placed with their longer diameter parallel,
or nearly so, to the femur and to the course
of the artery. Their relation to the artery is
not in all cases the same, inasmuch as the
disposition of neither part is strictly uniform,
but usually one or two of them lie over the
vessel, or immediately on either side of its
course; their relation to it, however, is, in
the natural condition of the parts, not of great
consequence; for in such case they may be
easily held aside during operation if necessary,
and thus both they and their lymphatic vessels
be saved from injury.

The relation of the inguinal glands, more
particularly the superior, to the femoral artery
suggests several inferences. 1st, That the
very commencement of the artery's course,
although the situation in which the vessel is
nearest to the surface, and that in which it
can be most easily distinguished by its pulsa-
tion, is yet not the most eligible part at which
to expose it, since the glands and their vessels
cannot, by any precaution of the surgeon, be
protected certainly from injury. 2dly, That
phagedenic ulceration of the glands of the
groin must be attended with great danger from
the vicinity of the great vessels. 3dly, That
hemorrhage consequent upon such ulceration
does not necessarily proceed from those vessels
themselves ; but that it may, and in the ma-
jority of cases in the first instance probably
does arise from the branches supplying the
glands ; and, 4th, That the groin is likely to be
the seat of pulsating tumours requiring to be
distinguished from aneurism.

The third covering of the artery is the
superficial lamina of the iliac portion of the
fascia lata. This portion having covered the an-
terior surface of the iliacus and psoas muscles
as far as the middle of Poupart's ligament,
along which it is attached from without inward,
divides at that point into two laminae, a deep

one and a superficial one ; the former passes
inward and backward from the ligament, upon
the psoas muscle, to the ilio-pectineal eminence
of the os innominatum, into which it is in-
serted, continued thence upward, upon the
inside of the muscle, along the brim of the
pelvis into the fascia iliaca, and downward
across the capsule of the ilio-femoral articula-
tion, to which it is also attached : it is in
fact that part of the fascia iliaca, (for the fascia
iliaca and the iliac portion of the fascia lata
are one and the same expansion, distinguished
from each other only by Poupart's ligament,)
which is situate upon the inside of the psoas
magnus, and which forms the outer wall of
the femoral canal, being interposed between the
femoral artery and the muscle. At the ilio-
pectineal eminence it also meets and is iden-
tified with the pubic portion of the fascia
lata, which is attached to the pectineal line
of the pubis, in continuation with this deep
lamina of the iliac portion, covers the pectinalis
muscle, and is situated immediately behind
the vessels. When that part of the deep
lamina of the iliac portion of the fascia lata
which extends from Poupart's ligament to the
ilio-pectineal eminence has had the prolonga-
tion of the fascia downward detached from it,
it appears as an oblique partition dividing
the crural arch into two parts, an external
containing the iliacus and psoas muscles with
the crural nerve, and an internal containing
the femoral vessels.

The second lamina of the iliac portion of
the fascia lata — the superficial one — passes
inward across the femoral vessels, superficial
to them and to the prolongation of the fascia
transversalis, until it has reached the inside
of the vessels : it is at the same time attached
above, in front of the vessels, and in con-
tinuation with the iliac portion itself, to the
inferior margin of Poupart's ligament, from
its middle to the base of its third insertion —
Gimbernat's ligament, and upon their inside
along the base of the latter ligament as far
as the pectineal line of the pubis, into which
it is finally inserted, external to the base of
Gimbernat, between it and the insertion of
the fascia transversalis upon the inside of the
aperture of the femoral sheath, and where
it is also identified with the pubic portion
of the fascia attached along the same line :
from thence it is united to the anterior surface
of the pubic portion of the fascia lata, down-
ward along the inside of the vessels. The
superficial lamina of the iliac portion is thus
thrown across the front of the vessels, and
by the disposition, which has been detailed,
the fascia lata encloses the vessels between the
two laminae, and forms, by means of them
and their connection at either side, a canal,
within which are contained the vessels and
the prolongation of the fascia transversalis
covering them in front. The constitution of
the canal, as described, may be considered
to extend from Poupart's ligament until the
artery is about to be covered by the sartorius,
from whence its anterior wall is formed, through
the remainder of the vessel's course, by another

240

FEMORAL ARTERY.

and deeper layer of the fascia. The canal
thus formed, to which the author would apply,
with Cloquet, the term femoral canal, is
widest at its upper extremity, i. e. at Poupart's
ligament; from whence, as it descends, it
contracts in width until it has passed the
entrance of the saphena, beyond which it
continues of nearly uniform capacity to its
termination. The diminution in the transverse
extent of the canal is due to the direction
of the line of union between the superficial
lamina of the iliac portion and the pubic
portion of the fascia, which, as has been
already stated, inclines outward as it descends
from the pectineal line of the pubis to the
point at which the saphena joins the femoral
vein. In the interval between Poupart's
ligament and the junction of the two veins
the superficial lamina is thinner, less aponeu-
rotic, and more of a cellular character than
other parts of the fascia ; but it is subject to
much variety in this respect : in all cases it
is thinner and weaker internally than externally,
but in some it is throughout distinct and un-
broken, unless by the passage of vessels, and
presents aponeurotic characters as decidedly as
many other parts of the expansion ; while in
others it is cellular, indistinct, and even fatty,
not easily distinguishable from the subcuta-
neous structure, and so thin as to seem de-
ficient toward its inner part, or to have its
line of union with the pubic portion inter-
rupted at one or more points. The extent
and connections of this portion of the fascia
will be most satisfactorily displayed by first
detaching Poupart's ligament, upon its abdo-
minal side, from the fascia trans versalis as it
descends beneath the ligament, and then care-
fully insinuating the handle of a knife down-
ward beneath the ligament and the superficial
lamina of the iliac portion of the fascia lata,
between them and the prolongation of the
fascia transversalis : this done, the superficial
lamina may, with the guidance of the instru-
ment beneath it, be satisfactorily traced.

The fourth structure, by which the femoral
artery is covered in the first stage of its course,
is the prolongation of the fascia transversalis.
The two abdominal fasciae, the transversalis
and the iliaca, which are, at every other part
of the crural arch, either identified and united,
or inserted into bone, are separated in the in-
terval between the middle of Poupart's and
the base of Gimbernat's ligament, and de-
scend into the thigh, the former in front of or
superficial to the femoral vessels, beneath Pou-
part's ligament and the superficial lamina of
the iliac portion of the fascia lata ; the latter
behind or deeper than the vessels, between
them and the psoas and pectinalis muscles,
constituting or continued into the pubic or
deep portion of the fascia lata. The two fasciae
thus leave an aperture beneath Poupart's liga-
ment, through which the vessels escape from
the abdomen, and at the same time inclose
them between them ; the prolongation of the
transversalis covering them in front, the iliac
and pubic portion of the fascia lata situate
behind them. As it descends upon the vessels,

the prolongation from the transversalis is united
to the fascia iliaca and iliac portion of the
fascia lata upon their outside; and to the pubic
portion upon their inside, in the same manner
as the superficial lamina of the iliac portion,
and within it in reference to the femoral canal :
it may therefore be viewed in one of two lights
with regard to that canal, viz. either as de-
scending into it superficial to the vessels, and
entering into the constitution of its anterior
wall, or as concurring with the other fasciae to
form, beneath the superficial lamina of the
iliac portion of the fascia lata, a sheath, in
which the vessels are immediately contained.
The latter is the view which has been adopted
by anatomists, and the appellation femoral has
been given to the sheath so formed. Like the
superficial lamina of the iliac portion of the
fascia lata, the prolongation of the fascia trans-
versalis is wider at Poupart's ligament, and
diminishes in width as it descends to the junc-
tion of the saphena and femoral veins : hence
the femoral sheath is considerably larger supe-
riorly than inferiorly, does not embrace the
vessels closely at their entrance into the thigh,
and but for the aponeurotic expansion described
by Colles, and termed by Cloquet the crural
septum, would be open toward the abdomen ;
but in proportion as they descend, it invests
them more closely until it reaches the entrance
of the saphena, at which point its connection to
them is intimate, and from whence the prolon-
gation seems to the author to be continued down-
ward into the dense thin cellular or nbro-cellular
investment, by which the artery and vein are
surrounded and connected together within the
femoral canal during the remainder of their
course through the thigh. From Sir A. Coo-
per's account of the prolongation it would
appear that it terminated, or cannot be traced
further than two inches below Poupart's liga-
ment. Sir Astley says, " these vessels pass
down within the sheath for about two inches,
after which they carry with them a closely
investing fascia derived from the fascia lata."
By the " closely investing fascia," the author
understands the proper sheath of the vessels,
which has been adverted to, and with which
the prolongation of the fascia transversalis
appears to him to be identified. According to
Professor Harrison,* " it soon becomes thin
and indistinct, and is lost in the cribriform
part of the fascia lata;'7 but in this view of its
termination the author cannot concur ; the pro-
longation is doubtless connected to the cribri-
form fascia (the superficial lamina of the iliac
portion of the fascia lata) by the vessels, which
traverse both structures, but it is notwith-
standing separable, without much difficulty,
from it, by means of the proceeding already
recommended for the display of that part —
a proceeding equally applicable to that of the
distinct existence and the connections of the
expansion in question ; the superficial lamina
being at the same time, as directed by Colles,
divided from above downward, and its parts
held to either side, inasmuch as a thin cellular

* Dublin Dissector, p. 153.

FEMORAL ARTERY.

241

or adipose stratum is interposed between them.
The last particular in the disposition of the
prolongation of the fascia trans versalis, having
reference to the femoral artery, is, that it is
connected to the back of the femoral canal
(the pubic portion of the fascia lata posterior
to the vessels) by two septa or partitions,
placed, one between the artery and vein, upon
the inside of the former ; the other internal to
the latter, between it and the femoral ring:
by those the abdominal aperture of the femoral
sheath is divided into three compartments:
an external one occupied by the artery, a mid-
dle one by the vein, and an internal by the
lymphatics, and at times by a gland. The
two former are so protected that the occurrence
of hernia through them is rare ; in the case of
the first probably impossible; but the internal,
whether from weakness or deficiency of pro-
tecting provisions, allows its protrusion, and
hence the relation of the femoral vessels, and
more particularly of the artery to the neck of
the sac of femoral hernia, upon the outer side
of which it is always situate, separated from it
by the vein.

At the lower part of the first stage the artery
is crossed obliquely by the most internal of the
deep branches of the crural nerve, which for
distinction sake might be called internal geni-
cular : it enters the femoral canal on the out-
side of the vessels above, at a variable distance
from Poupart's ligament; descends from
without inward upon the front of the artery
within the canal ; and escapes from it below
on the inside of the vessel under cover of the
sartorius. Situate, as the nerve is, within the
femoral canal, upon the front of the artery,
and closely connected to it by the femoral
sheath, it is very likely, unless care be taken
to avoid it, to be included in a ligature at the
same time with the vessel : it will not, how-
ever, be always encountered, inasmuch as it
crosses the artery, and at a point higher or
lower in different subjects.

At times a second branch of the crural
nerve crosses the artery in like manner as the
former and lower down, but it is not to be
always observed.

Posteriorly in its first stage the artery rests, first
upon the inner margin of the psoas magnus,
from which it is separated by the deep lamina
of the iliac portion of the fascia lata: while
so related, it is situate over the anterior surface of
the os innominatum, external to the iliopec-
tineal eminence, having the two structures,
already mentioned, interposed.* Below the

* In this the author has ventured to differ from
the account usually given of the relation of the
artery to the os innominatum, according to which
(Boyer, Cloquet,) the vessel must be understood
to be situate internal to the point mentioned, being
said to lie upon the os pubis ; but in his opinion
this is not correct. The artery lies on the psoas,
which is not internal to the eminence, and upon
the deep lamina of the iliac portion of the fascia
lata covering the muscle, which at its most internal
part is inserted into the eminence ; consequently
the vessel, which lies on the lamina, must be ex-
ternal to that point of bone, and observation will
be found to confirm this view.
VOL. II.

os innominatum it is placed over the head of
the femur, from which it is separated by the
same parts, and also by the capsular ligament
of the articulation, and the synovial bursa,
which exists between the front of the capsule,
and the psoas and iliacus muscles. There are
then in this situation two resisting surfaces
against which compression of the vessel may
be effected; and here also, as observed by
Harrison, a tumour with pulsation may occur
in case of effusion either into the bursa simply,
or into the joint, when a communication exists
between the former and the synovial membrane
of the latter.

Having passed the margin of the psoas and
the head of the femur, the artery corresponds
to the tendon of the psoas and iliacus, to the
pectinalis, and to a small portion of the ad-
ductor brevis, which parts it crosses obliquely
in its descent : it is not, however, in contact
with them, but is separated from them by a
space of some depth occupied by cellular
structure and vessels. The distance of the
artery from the muscles varies according to
circumstances : when the thigh is extended or
rotated inward, it is increased; when, on the
other hand, it is flexed or rotated outward,*
it is diminished : in the former case, the artery
is brought nearer to the anterior surface of the
thigh by the extension, and by the rotation
the lesser trochanter, which is in the middle
and deepest part of the space, is carried back-
ward from that surface.

The vessels which occupy the interval be-
tween the artery and the muscles are the pro-
funda vein, the circumflex veins, and the
femoral vein in part, they being next to the
artery and immediately behind it ; posterior to
them are, at times, the profunda artery, and
at the upper part, according to circumstances,
one or other of the circumflex arteries, when
arising, as in ordinary, from it.

External to the artery in its first stage are
the psoas and iliacus muscles, the sartorius,
the rectus, and the upper extremity of the
vastus internus muscles ; from all which it is
separated by the wall of the femoral canal.
At the entrance of the artery into the thigh,
and for about an inch below Poupart's liga-
ment, the crural portion of the genito-crural
nerve is contained within the femoral canal in
immediate apposition with the vessel upon its
outer side. External to it are situate also the
crural nerve above, and itssaphena branch below.
Except in rare instances, the profunda artery
lies on the outer side of the femoral during a
greater or less extent of its first stage; but it
is, unless occasionally near to its origin, at the
same time posterior to it, and is subject to
varieties in its relation which will be more
particularly detailed in the description of that
vessel.

Internally the artery corresponds, though at
a distance, to the pectinalis and adductor mus-
cles. The femoral vein at the upper part is
very nearly upon the same level ; the artery,
however, is somewhat anterior to it, probably

* Harrison.

242

FEMORAL ARTERY.

from resting upon the psoas, while the vein
corresponds to the pubes between that muscle
and the pectinalis: hence the two vessels at
their entrance into the thigh, allowance being
made for the trifling difference which has been
mentioned, lie side by side, the vein internal
to the artery ; but as the former descends from
the pubes, it recedes from the surface more
than the artery, and at the same time inclines
outward, and thus it becomes posterior to it
at the lower part of the stage, so as to be con-
cealed by the artery by the time it has reached
its termination. It is included with the artery
in the femoral sheath, and is separated from it
by the external of the two septa, which have
been described.

In its second stage the relations of the artery
differ considerably from those in its first. In
the first place it is covered throughout by the
sartorius, the muscle crossing it obliquely from
without inward, and thence first overlapping it
by its inner edge, and gradually extending over
it until the vessel is directly covered by it.
Secondly, it is in consequence covered by two
laminae of the fascia lata enclosing the muscle;
one superficial to it, the other beneath it, form-
ing the front of the femoral canal ; it has then
two new coverings, the muscle and the second
lamina of the fascia. Thirdly, the femoral vein,
which is very closely connected to the artery,
is directly behind it, between it and the adduc-
tor longus muscle, to which the artery corre-
sponds posteriorly. Fourthly, it has no part
deserving of attention upon its inside; and,
lastly, the saphenus nerve is within the femoral
canal, along the outer side of the artery and
anterior to it.

The inferior third of the artery also presents
some peculiarities of relation. The vessel is
still covered by the sartorius; but here the
muscle is more to the inner, as in the second
stage it is more to the outer side of the vessel,
not only connecting it in front, but also lying
against its inner side, and the more so the
nearer we approach the termination of the
stage ; so much so indeed, that at its termina-
tion, the artery, when injected, may be felt
beneath the outer margin of the muscle ; and
hence the difference between the mode of pro-
ceeding with regard to the sartorius recom-
mended generally to be adopted, when occasion
arises for seeking the artery in its inferior third,
and that to be pursued when the vessel is to
be exposed in its second stage ; it being ad-
vised, in the latter case, to displace the inner
edge of the muscle outward, and in the former
the outer inward, in order to reach the vessel
with the greatest ease and certainty. The ves-
sel is also covered by the same two laminae of
the fascia ; but the deep one presents at this
part remarkable features : it increases in thick-
ness and is more aponeurotic in proportion as
it descends, and hence it is stronger the nearer
we approach the termination of the course of
the artery ; but in the inferior third its thick-
ness is still further augmented by numerous
tendinous fibres, which pass from the tendons
of the adductors longus and magnus to that of
the vastus internus, add very much to the

thickness of the fascia, and give to It the ap-
pearance of a tendinous expansion of great
strength, connecting the tendons of the mus-
cles, which have been mentioned, and covering
the artery upon its anterior and internal sides.
It is also to be observed that this accession of
fibres from the tendons exists only in the infe-
rior third of the artery's course, and not in its
middle stage, and hence the covering of the
vessel beneath the sartorius, or the anterior
wall of the canal, is much thicker and stronger
in the former than in the latter ; and hence
also one of the difficulties encountered in
getting at the vessel in the third stage. The
artery in this third stage is situate upon the
inside of the shaft of the femur, crossing it ob-
liquely from before backward : it is not, how-
ever, in contact with the bone, but is separated
from it by the vastus internus muscle : it is
enclosed, as before stated, between muscles ;
the sartorius before and internal to it, the ad-
ductors longus and magnus behind it, and the
vastus internus on its outside.

The other relations of the vessel in this stage
are to the saphena vein, the saphenus nerve,
the femoral vein, and the superficial superior
internal articular artery. The first is situate
between the femoral artery and the internal
face of the thigh, for the most part along the
inner margin of the sartorius, but varying some-
what in this respect, lying at times upon the
muscle, from its middle to its inner edge, and
at others posterior to it. The saphenus nerve
is placed at first, as in the second stage, exter-
nal and anterior to the artery, but it crosses it
at its termination and escapes from the canal,
upon its inside, in company with the superficial
articular artery, as the vessel is about to pass
into the popliteal space. The femoral vein is
behind the artery and somewhat external to it :
the latter relation of the vein is expressly de-
nied by Velpeau,* but after careful examina-
tion the author does not hesitate to affirm it.

The superficial superior internal articular
artery, a branch of the femoral, is given off by
the artery immediately before its termination ;
it arises from the front of the vessel, descends
nearly in the course of it, escapes from the
femoral canal in company with the saphenus
nerve, and, holding generally the same relation
to that nerve which the femoral itself does, may
hence be mistaken for that artery at the inferior
part of its course.

Thus the relations of the vessel are here in
several particulars the reverse of those in its
former stages, and the methods most eligible
for adoption in operation ought to be varied
accordingly. Operation in its last stage is
seldom required, but it may be necessary, as
in wounds of the artery at that part, in which
case the mode of proceeding with regard to the
sartorius and to the artery should be the reverse
of that recommended for the upper stage, the
muscle being to be displaced inward in order
to expose the artery, and the separation of the
latter from the vein to be effected in the same
direction.

* Anatomic des Regions, t. ii. p. 485. ed. 1.

FEMORAL ARTERY.

243

At the termination of its third stage the
artery passes into the ham and there receives
the name of popliteal : it enters the popliteal
region through an elliptical aperture situate to
the inside of the femur at the junction of its
middle and inferior thirds, and upon a plane
with its posterior face, the longer diameter of
which corresponds to the course of the artery,
and which is circumscribed by the lower mar-
gin of the united tendons of the adductor
longus and the adductor inagnus above, by the
connection between the tendon of the adductor
magnus and that of the vastus internus below ;
by the tendon of the adductor magnus inter-
nally, and by that of the vastus internus exter-
nally : in passing through, the artery carries
with it a prolongation of the femoral sheath, by
which the popliteal vessels become invested
and connected.

Varieties. — The superficial femoral artery sel-
dom presents a variation from its accustomed dis-
position,so much so that it may almost be held to
be uniform in this respect : however two forms
of deviation have been observed, rare in occur-
rence, but of great importance in a practical
point of view. Two instances of the first ab-
normal arrangement are recorded, one of which
occurred to Sir Charles Bell, and has been pub-
lished by him in Anderson's Quarterly Journal
for the year 1826: the second is preserved in
the Museum of the College of Surgeons, and
has been described in the fourth volume of the
Dublin Hospital Reports by Dr. Houston,
Conservator to the Museum. In these cases
the femoral artery divided into two vessels of
nearly equal size, which pursued the usual
course of the artery side by side and very close
together, not, however, in contact, but contained
in distinct compartments of the sheath and
separated by a septum : hence the existence of
the second artery might in operation easily pass
unobserved, it not being brought into view by
opening the sheath of the other. One was
also larger than the other, and situate internal
and on a plane posterior to it. In Bell's case
the discovery was the consequence of the un-
fortunate event of an operation for popliteal
aneurism ; the operation was performed in the
middle third of the thigh. The pulsation of
the aneurism, which was arrested on the appli-
cation of the ligature, returned after an interval
of some seconds, and became nearly as distinct
as before : it ceased again upon the third day,
but the patient was carried off on the sixth day
by an erysipelatous inflammation of the thigh.
On examination after death, it was ascertained
that the disposition, which has been described,
was present, and that but one of the two vessels
had been tied.

The second form of deviation is a high
bifurcation into the posterior tibial and peroneal
arteries : of this an instance* has been recorded
by Sandifort, in which the division took place
immediately below Poupart's ligament ; and
Portalf states that the crural artery has been
seen to divide into two large branches shortly

* Green on the Varieties in the Arterial System,
and Sandifort, Observ. Anat. Pathol. iv. 97.
t Anatomie Medicale, t. iii. p. 326.

after its escape from the abdomen, and then
there were two popliteal arteries: he further
states that among individuals, in which the
brachial artery was bifurcated higher than usual,
the crural artery was so also in a remarkable
proportion.*

A division of the femoral artery into two
trunks of equal size, running parallel and so
near together, that they might be conveniently
included in one ligature, is recorded by Gooch
in the Philosophical Transactions for the year
1775, it being the third instance in amputations
of the thigh, in which he had observed such a
lusus nature in the arterial system ; but it is
not mentioned whether they were instances of
the first or of the second kind of variety : he
himself, whether from examination or from in-
ference, appears to have concluded that both
trunks were prolonged into the lower part of
the limb.

Those deviations have been accounted repe-
titions of similar irregularities in the brachial
artery, than which, however, they are far less
frequent. It is a matter to be regretted that
neither in the case of Bell, nor in that of
Houston, has any account been given of the
disposition of the artery of the upper extremi-
ties or of the other thigh.

Branches of the femoral artery. — The
branches given off by the femoral artery are
numerous ; but the trunk of the vessel being
itself intended for the supply of the leg and
foot, the branches which it gives to the thigh
are, with the exception of one intended speci-
ally for the nutrition of that part, inconsider-
able in size. The artery gives branches to the
integuments of the abdomen, to the glands and
other structures in the groin, to the external
organs of generation, to the muscles in the
vicinity of which it passes, to the inner side of
the knee ; and, lastly, it gives the large branch,
adverted to, for the supply of the thigh, and by
which those inosculations with other arteries
are formed, by means of which chiefly an in-
terruption in the course of the main vessel is
compensated. Those which have received
names are five, viz. \. the superficial epigas-
tric ; 2. the superficial or external pudic ; 3.
the superficial anterior iliac; 4. the profunda;
and 5. the superficial superior internal articular
arteries.

Of those the first four arise from the artery
within its first stage ; the epigastric, iliac, and
pudic being given off immediately or at a very
short distance below Poupart's ligament; and
the profunda at a greater although a variable
distance from that part.

1 . The superficial epigastric artery (artere
sous-cutanie abdominale, Cloquet ; inguinale,
Chaussier;) ordinarily arises from the front of
the femoral, immediately below Poupart's liga-
ment. Sometimes it is given off from a branch
common to it and either one or both the ex-
ternal pudics ; or it may proceed from the pro-
funda.f It first comes forward through the
fascia lata, and then ascends over Poupart's

* Ibid. p. 239.
t Boyer.

R 2

244

FEMORAL ARTERY.

Hgament upon the inferior part of the abdomen,
superficial to the aponeurosis of the external
oblique muscle, and enclosed in the subcuta-
neous cellular stratum. Its course is irregular,
at times nearly parallel* to that of the deep
epigastric within the abdominal wall ; at others
ascending directly upon the abdomen ; in ge-
neral it pursues the latter course. It is consi-
derably smaller than the deep epigastric artery,
and is concerned altogether in the supply of
superficial parts, and in establishing commu-
nications with other vessels. Its first branches
are distributed to the inguinal glands and co-
verings : during its ascent upon the abdomen
it gives to either side branches which supply
the superficial structures, and inosculate through
the ventral foramina with branches of the inter-
nal epigastric from within ; and it terminates
by communicating with the same and with
those of the internal mammary, and of the
inferior intercostals. It is, unless in case of
disease, a small vessel, and of consequence
only from being exposed to be divided in cer-
tain operations, viz. that for inguinal hernia,
or that for tying the external iliac artery.

2. The superficial or external pudic arteries
(scrotales ou vulvaires, Chauss.) are generally
two, distinguished into superficial^ and deep,
or superior \ and inferior: of those distinc-
tions the latter seems preferable, inasmuch as
they are both equally superficial in their dis-
tribution, and the difference between them in
this particular amounts to no more than that
the second continues longer beneath the fascia
lata than the first. They arise in general either
directly from the femoral, or from a trunk com-
mon to them with the superficial epigastric,
with which they are of nearly equal size.

The superior is given off' immediately below
Poupait's ligament; comes through the fascia
lata, and at the same time gives branches to the
inguinal glands ; runs, superficial to the fascia,
inward and also upward toward the pubes;
and either divides into two, one of which as-
cends above, the other, the more considerable,
continues below that part; or, as it proceeds,
it gives off small branches which ascend above
the pubis, and supply the superficial struc-
tures upon the inferior middle part of the ab-
dominal wall; while it is itself continued to the
scrotum and side of the penis, the coverings
of which it supplies; or into the labium in the
female. Its branches communicate with those,
which the external organs of generation receive
also from the internal pudic artery, and with
branches of the epigastric arteries. This branch
is usually divided in the operations for either
inguinal or femoral hernia.

The inferior external pudic artery arises from
the femoral at a greater distance from Poupart's
ligament than the former: at times it is given
oft' by the profunda§ artery, or from the in-
ternal circumflex,||or from the superior branch :lf
at others it is absent.** It is situate beneath the

Harrison. f Cloquet. $ Harrison.
Boyer, Cloquct, Tiedemann.
Harrison.
Ibid. ** Ibid.

fascia lata through a greater extent of its course
than the superior; runs inward across the pec-
tinalis muscle, covered by the fascia; passes
then through the fascia, and gains the scrotum
or the labium and the perineum, in which it is
distributed, communicating with the inferior
branch of the former and with the perineal
artery. Its course is at times so far from Pou-
part's ligament that it crosses behind the sa-
phena vein.

Occasionally a third* external pudic artery
is present, arising either from the femoral itself,
the profunda, or the internal circumflex artery.

3. The superficial anterior iliac artery (ar-
teria circumjiexa ilii superficialis, Harrison ;
external cutaneous, Scarpa ; artcre musculaire
superficielle, Cloquet ;) arises from the outer
side of the femoral artery, or at times from the
profunda :f it runs outward in front of the
crural nerve, and after a short course divides
into three branches. Its first comes from within
the fascia lata and is distributed to the superfi-
cial inguinal glands : its second branch also
comes through the fascia, runs round the ante-
rior and outer side of the thigh, below the
spinous process of the ilium, and is distri-
buted superficially: and its third runs outward
and upward, beneath the fascia lata, toward
the superior anterior spinous process of the
ilium ; supplies the sartorius and tensor vaginae
muscles at their origin, and also gives branches
to the iliacus interims. This artery communi-
cates with branches of the gluteal, the deep
anterior iliac, and the external circumflex
arteries.

4. The profunda artery (arteria profunda
femoris; intermusculaire, Chauss.) is the vessel

by which the muscles and other structures of
the thigh are for the greater part supplied,
whence it may be regarded as in strictness the
femoral artery, the trunk of the femoral, in its
general acceptation, being distributed to the
leg and foot : it is also the channel through
which the communications between the femoral
artery and the main arteries of the trunk on the
one hand, and of the lower part of the limb
on the other, are established, and by which, in
case of interruption of the first vessel, either
below or above the origin of the profunda, the
circulation is to be restored : it is therefore an
artery of great importance, and also of great
size, being nearly equal to, though for the most
part somewhat smaller than, the femoral itself,
while in many cases it is fully equal to it. Hence,
probably, it has received the name profunda
femoris, deep femoral artery; and by many the
femoral artery is distinguished into the common
femoral and the superficial and deep femorals;
the first extending from the entrance of the
vessel into the thigh to the origin of the pro-
funda ; the second being the vessel from the
point last mentioned to that at which it becomes
popliteal ; and the third the artery which is at
present under consideration.

The profunda artery for the most part arises
from the posterior and outer side of the femoral

* Scarpa, Boyer.
f Cloquet, Scarpa.

FEMORAL ARTERY.

245

at a distance, varying from one to two inches,
below Poupart's ligament : it descends thence
backward into the inguinal region, posterior
to the femoral artery, and correspondrng to
the muscles situate behind them in the same
order as the femoral itself until it reaches the
adductor longus : it then passes behind that
muscle and continues its descent between it
and the adductor magnus, until after it has
given off its last perforating branch, when it
also perforates the magnus at the lower part of
the middle third of the thigh, and finally is
distributed to the short head of the biceps and
the vastus externus, gives to the femur its in-
ferior nutritious artery, and anastomoses with
the descending branches of the external cir-
cumflex artery, and with branches of the pop-
liteal. During its descent the profunda recedes
from the surface more than the femoral artery,
so that it lies nearer to the bottom of the in-
guinal space, and when placed directly behind
it, is separated from that vessel by an interval,
which is occupied by the femoral, the pro-
funda, and the circumflex veins. It is accom-
panied by a corresponding single vein of con-
siderable size, the profunda vein, which in the
upper rjart of the thigh is situate before the
artery, intervening, as has been mentioned,
between it and the femoral artery. It is con-
tained at first within the same sheath with the
femoral; but it is presently received into a
proper sheath, an offset from the back of that
which encloses the other vessel. It has not an
immediate relation to any nerve.

Such are the general relations of the pro-
funda artery ; but it presents frequent varieties,
which derive importance from the practical
connections of the femoral vessels. The par-
ticulars, in which it is subject to diversity, are
the precise situation and relation of its point
of origin, and the relation of its course to that
of the femoral artery.

The profunda arises generally, as has been
stated, from the posterior and outer side of the
femoral ; but at times its origin is directly
behind that vessel, at others directly from its
outer side, and occasionally again from its
inner side, as may be seen from fig. 3, tab.
xxxiii. of Tiedemann. The situation of its
origin also is variable, at times being close to
Poupart's ligament, at others at some distance
from it. According to Boyer* it corresponds
to " the middle of the space comprised be-
tween the pubis and the little trochanter ;
sometimes higher, but rarely lower." Accord-
ing to Scarpa,f the division of the femoral
artery takes place " at the distance of one
inch, or one and a half, very rarely two inches,
below the crural arch in a well-formed adult,
of the ordinary stature." According to Har-
rison,]; the profunda arises " in general about
two inches below Poupart's ligament, some-
times an inch or two lower down, and some-
times much nearer to this ligament." Of those

Traite complet d'Anatomie, torn. iii. p. 150.
t Treatise on Aneurism, Wishart's translation,
p. 3.

J Op.cit. vol. ii. p. 144.

three accounts that of Scarpa appears pre-
ferable : the. " distance between the pubis and
the lesser trochanter" is variable, and affords
no guide for the living subject, and the author
has never witnessed the origin of the vessel
by any means so far from Poupart's ligament
as the statement of Harrison would imply:
a distance of four inches, which may be un-
derstood from it sometimes to occur, would
bring the origin down to the point at which the
sartorius generally commences to overlap the
femoral artery, and this is manifestly alto-
gether too low; while on the other hand

Scarpa* stales expressly that it is never below
the maximum point which he has laid down,
viz. two inches from the ligament, and Hodg-
son f asserts that " it very rarely arises so low
as two inches." The maximum distance im-
plied in the description of Harrison is that
which has been laid down by Bell as the me-
dium point of origin, on which Burns J re-
marks, " I infer that Mr. Bell has described
this artery from dried preparations, in which,
from the retraction of Poupart's ligament, the
origin of the profunda seems to take place
lower than on the recent subject." The only
objection which can be made to the view of
Scarpa, is that the vessel not unfrequently
arises nearer to the ligament than one inch
from it, its origin being at times abso-
lutely at it, and having been in some few
instances observed even above the ligament,
before the femoral had escaped from the ab-
domen, or more properly from the external
iliac artery : of this extraordinarily high origin
four instances have been recorded by Burns,§
and Tiedemann || has met with it in a female,
upon both sides. Tiedemann^ has also in-
ferred from his researches that the profunda
arises nearer than usual to Poupart's ligament
more frequently in females and in subjects of
small stature than in others.

The relation of the course of the profunda
to that of the femoral is the next point of
variety.

The main course of the former is external to
that of the latter; in arriving at its destination,
however, it does not at all times pursue an
uniform course, but presents diversities in this
respect, which affect very much its relation to
the femoral artery. Its general direction is
downward, backward, and outward; still more
outward than the femoral : it is seldom how-
ever direct, but describes one or more inflec-
tions, by which its course is made at times to
cross once or oftener that of the other vessel ;
and hence the diversities in its relation to the
femoral which have been adverted to. When
the course of the vessel is direct or little tor-
tuous, the profunda is situate throughout,
external to the femoral, and this relation would
appear to prevail at least as frequently as any

* Op. cit. p. 328.

t Treatise on Diseases of Arteries and Veins
p. 434.

J On Diseases of the Heart, &c. p. 319, 20.
$ Ibid.

jj ExplicatioTabularum Arteriarum, p. 323.
1 Ibid.

246

FEMORAL ARTERY.

other, or to be the most prevalent, for such is
the view of the course of the artery given by
Haller,* in two of three views in which the
relative course of the two vessels is repre-
sented, and by Tiedemannf in two of four
views. But at other times, when the artery is
more tortuous, after descending for a little
way external to the femoral, it makes a turn,
and passes inward behind it, and thus fre-
quently gains the inner side of that vessel
before it reaches the adductor longus, after
which it again inclines outward toward its
destination. Such is the view given of its
course by Scarpa,J with which the description
of Harrison coincides : it is similarly repre-
sented by Tiedemann in fig. 4, tab. xxxiii.,
and also by Haller§ in one instance ; but the
author is disposed to regard this as a less
common disposition, as well from the fre-
quency with which he has observed the former
one to occur, as from the weight of the autho-
rities which have been adduced in favour of
that opinion. In other but rare instances the
profunda, arising from the inside of the femo-
ral, inclines at first inward and becomes in-
ternal to it, and then bending outward crosses
behind the femoral to its outer side : of this
arrangement an instance is furnished by Tiede-
mann in fig. 3, tab. xxxiii. And in others
the artery does not in the first instance incline
sensibly to either side; but arising from the
back of the femoral it descends behind that
vessel, and does not gain its outer side until
it has reached the lower part of the inguinal
region.

When the profunda artery arises very near
to or above Poupart's ligament, and from the
outer side of the femoral, is large and pursues
its ordinary course, two arteries of equal or
nearly equal size may be found, at the upper
part of the inguinal region, side by side, and
upon the same level, and thence liable to be
taken, either of them, for the femoral artery.
When such an arrangement occurs, the ex-
ternal|| of the two vessels will almost certainly
be found to be the profunda, for if that artery
have once passed inward behind the femoral,
it cannot afterward gain the same level with it,
so as to be situate at the same time internal to
and on the same plane with it : further, as the
profunda descends, it recedes from the an-
terior surface more than the femoral, in order
to pass behind the adductor longus, and thus
it gains at the lower part of the region a deeper
situation than the other. But inasmuch as the
profunda occasionally arises from the inside of
the femoral artery, it may be possible for it,
in case of high origin, to be the inner of the
two vessels adverted to. Such a circumstance,
however, if it ever occur, must be extremely
rare, but in order to guard against it, the pre-

* Icones Anatomicae.

t Tabulae Arteriarum. Tab. xxxi. and fig. 2.
tab. xxxiii.

\ Reflexions et Observations Anatomico-chirur-
gicales sur 1'Aneurisme, tab. lere.

$ Op. cit.

\\ Harrison, op. cit. vol. ii. p. 165. Hargrave,
System of Operative Surgery.

caution recommended of alternately compres-
sing the vessels and ascertaining the effect
previous to the application of a ligature, should
never be neglected.

Branches of the profunda artery. — The pro-
funda gives off a considerable number of
branches, some of which being distributed to
the muscles, by which the artery passes, and
not being remarkable either for their size or
their communications, have not received par-
ticular names. Those which are most de-
serving of attention, whether for their size,
the extent and peculiarity of their course, or
the anastomoses which they form with other
arteries, are five or six in number, viz. two
circumflex arteries, and three or at times four
perforating arteries. The circumflex arteries
are so named because they wind round the
upper extremity of the femur, and form an
arterial circle around it : they are distinguished
by the epithets external and internal, being
destined, one to the outer, the other to the
inner side of the limb : they are vessels of
considerable size and importance because both
of the extent of parts which they supply, and
of the communications which are established
through them between the femoral, the arteries
of the pelvis, and those of the lower parts of
the limb.

1. The external circumflex artery at times
is the first branch of the profunda; at others
it is preceded by the internal circumflex : it is
given off from the profunda while it lies on
the outside of the femoral at a variable dis-
tance from Poupart's ligament, and arises from
the outer side of the artery : occasionally it is
given off by the femoral itself; it runs directly
outward, or outward and downward, in front
of the psoas and iliacus muscles; beneath the
sartorius and rectus, and either between or
behind the divisions of the crural nerve ; and
divides after a short course into three branches,
viz. an ascending, a descending, and a circum-
flex.

«. The first, the ascending branch, runs up-
ward and outward toward the superior anterior
spinous process of the ilium, between the
iliacus internus and the glutceus medius mus-
cles, and concealed by the tensor vaginae
fernoris: as it proceeds, it gives branches to
those muscles; and having reached the outer
and back part of the spinous process, it ter-
minates in an anastomosis with a branch of
the glutreal, and also with the deep cir-
cumflex ilii arteries. The anastomosis with
the glutceal artery becomes remarkably en-
larged when the main vessel is interrupted
above the origin of the profunda, as may be
seen from Sir A. Cooper's case of femoral
aneurism.*

b. The second, the descending branch, runs
downward and outward beneath the rectus
muscle, between it and the triceps crural, and
divides after a short course for the most part into
several branches of considerable size and great
length for the supply of those muscles and for
establishing communications : the branches are

* Guy's Hospital Reports, Jan. 1836, pi. 1.

FEMORAL ARTERY.

247

at times so many as five or six, and are dis-
tributed one or more to the rectus, entering
the muscle upon its deep surface, and pro-
longed to a great length within its substance ;
one to the vastus internus, one to the cruraeus,
and one or two to the vastus externus : they
are accompanied, several of them, by branches
of the crural nerve, and they run for a con-
siderable distance, particularly the infe-
rior branch to the vastus externus, between
the divisions of the triceps crural muscle,
before entering their substance : they are pro-
longed very low down, and may be followed
some of them to near the knee, where they
anastomose with branches of the femoral in
the vastus internus, and with the superior
articular arteries. But the branches of the
descending division of the external circum-
flex artery are by no means uniform in number
or destination, more or fewer of the arteries
just described being at times branches of the
profunda itself; thus, at times that to the
vastus internus, that to the cruraeus, and that
to the rectus, arise from the profunda below
the circumflex, and in such case the descend-
ing branch of the latter consists solely of the
branch or branches destined to the vastus ex-
ternus muscle.

c. The third, the circumflex branch, pursues
at first the course of the original vessel, and
runs outward across the upper extremity of the
shaft of the femur below the great trochanter,
beneath the rectus and tensor vagina? muscles,
and superficial to the cruraeus. It gives, in
this situation, branches to the cruraeus, the
iliacus, the rectus and tensor muscles. It
then passes backward upon the outside of the
femur to its posterior part, and thus surrounds
the bone upon its anterior and external sides.
In the latter part of its course it traverses the
upper extremity of the vastus externus, and
gives off, 1. branches upward and downward
into the muscle; 2. a branch or branches which
run between the vastus and the bone, and
supply the periosteum ; 3. a branch to the
glutceus maximus at its insertion, which, after
furnishing it branches, perforates the muscle
and becomes superficial. The circumflex divi-
sion of the external circumflex anastomoses
with the internal circumflex, the glutceal, the
sciatic, and the perforating arteries. The ex-
ternal circumflex artery is accompanied by a
large vein, which crosses between the femoral
and profunda arteries, superficial to the latter,
in order to join the femoral or the profunda
vein.

2. The internal circumflex artery is a larger
vessel than the external : it is given off by the
profunda usually after the external, and arises
from the inner side of the artery, but at times
it arises before the external. According to
Harrison it " very frequently proceeds from the
femoral artery, prior to the origin of the pro-
funda ;" it has been found by Burns* arising
from the external iliac artery, and also from the
femoral artery a little below the crural arch.
In the former case " it ran along the front of

the lymphatic sheath ;" and in the second " it
traversed the front of the common sheath of
the great vein and also of the lymphatics ;" and
in either case, as observed by Burns, it must
be exposed to great danger in operation for
femoral hernia. According to Green,* both
circumflex arteries sometimes are furnished
from a common trunk. It runs inward, back-
ward, and downward toward the lesser tro-
chanter into the deepest part of the inguinal
region, and escapes from that space posteriorly
between the tendon of the psoas and the pecti-
nalis muscles ; continues its course backward,
on the inside of the neck of the femur and the
capsular ligament, below the obturator exter-
nus, behind the pectinalis, and anterior to the
adductor magnus and the quadratus muscles,
until it has got behind the neck of the bone ;
and lastly, it passes through the internal, which
separates the inferior margin of the quadratus
femoris from the upper margin of the adductor
magnus, and thus gains the posterior region of
the thigh, where it terminates as will be de-
scribed.

The internal circumflex artery is the vessel
which gains the deepest situation in the groin :
it is internal and posterior to the profunda, and
when it arises from that artery, while external
to the femoral, it crosses the latter vessel poste-
riorly in its course. While within the inguinal
region the internal circumflex artery gives off
first a branch to the iliacus and psoas muscles :
then a considerable branch, denominated by
Tiedemann superficial circumflex branch, which
contributes to supply the pectinalis, the adduc-
tor longus, and the adductor brevis : it runs
upward and inward upon the pectinalis, at the
same time giving branches to it and to the ad-
ductor longus, until it reaches the interval be-
tween these muscles : it then divides into two,
of which one ascends in the course of the
original branch, between the muscles men-
tioned, toward the origin of the adductor longus,
supplying the two muscles, and ultimately
anastomosing with branches of the obturator
artery : small branches of it traverse the adduc-
tor, and become cutaneous upon the upper and
inner part of the thigh. The second branch
passes downward and backward, also between
the pectinalis and the adductor longus, gains
the anterior surface of the adductor brevis, and
there meets the obturator vessels and nerves :
it divides into several branches, of which some
are distributed to the last muscle, some anas-
tomose with the obturator artery, and others
with the upper perforating artery.

Behind the pectinalis the internal circumflex
artery gives several branches. Downward it
gives a considerable one to the adductor mag-
nus, which descends into that muscle, supplies
it and anastomoses with the perforating arteries.
Upward and forward it gives to the adductor
brevis and the obturator externus branches
which communicate freely with the obturator
artery after its escape from the pelvis. Out-
ward it gives the articular artery of the hip a
branch, small, but remarkable for its course and

* Op. cit. p. 319.

* Op. cit. p. 31.

248

FEMORAL ARTERY.

destination; it enters the articulation beneath
the transverse ligament, through the notch at
the internal and inferior part of the margin of
the acetabulum, over which the ligament is
thrown ; supplies the adipose structure which
occupies the bottom of the socket, and is con-
ducted by the ligamentum teres to the head of
the femur, in which it is ultimately distributed.
That part of the artery which reaches the head
of the femur is of very inconsiderable size, and
is the source upon which the nutrition of that
part depends in fracture of the neck of the bone
within the capsule. Lastly, upward and back-
ward the artery sends off a considerable and
regular branch which is usually described as
one of its terminating branches, but which, in
the opinion of the author, may with more pro-
priety be considered as belonging to its middle
stage. It passes upward and outward between
the obturator externus and the quadratus mus-
cles to the trochanteric fossa, where it is dis-
tributed to the muscles inserted behind the
trochanter, viz. to those which have been just
mentioned; to the obturator internus, the
gemelli, the pyriformis, the glutcei medius and
minimus, and to the back of the ilio-femoral
articulation, and where it inosculates with the
glutceal, sciatic, and external circumflex arte-
ries. Jt may be appropriately called the poste-
rior trochanteric* branch.

After its passage between the quadratus and
the adductor magnus, the circumflex artery
divides, in the posterior region of the thigh,
into an ascending and a descending branch.
The former passes upward to the origin of the
biceps, semi - membranosus and tendinosus
muscles, and to the glutceus maximus ; the
latter downward to the former muscles, to the
adductor magnus, and to the sciatic nerve.
They communicate with the sciatic, the exter-
nal circumflex, and superior perforating arte-
ries.

The perforating arteries are three or four in
number. They are given off backward by the
profunda, below the origin of the circumflex
arteries, and are denominated numerically first,
second, third, &c. They all pass from the an-
terior to the posterior region of the thigh by
perforating the adductor magnus, and at times
also the adductor brevis, whence their name ;
they divide for the most part into ascending
and descending branches, and are consumed
partly in the supply of that region, and partly
in establishing a chain of communications be-
tween the arteries of the trunk and the main
artery at the upper and the lower parts of the
thigh.

3. The first perforating artery arises from the
profunda immediately below the lesser trochan-
ter, nearly opposite the lower margin of the
pectinalis : it passes backward, descending a
little below the lower margin of the pectinalis,
either between it and the upper one of the ad-
ductor brevis, or through an aperture in the
latter muscle : it next perforates the adductor
magnus close to the linea aspera, and so gains
the posterior region of the thigh, where it

* Scarpa, op. cit.

divides into two or three large branches, of
which one ascends and is distributed to the
glutceus maximus, communicating with the
glutceal, sciatic, and circumflex arteries; ano-
ther descends, supplies the long head of the
biceps, the semi-membranosus and semi-tendi-
nosus, and communicates with the inferior per-
forating arteries ; and the third runs downward
and outward into the vastus externus, through
which it descends, communicating at the same
time with the external circumflex artery. The
artery also gives branches to the sciatic nerve,
and, during its passage from the front to the
back of the thigh, to the pectinalis and the ad-
ductors. According to Harrison, " this artery
is sometimes a branch of the internal circum-
flex ; its course is nearly parallel to that vessel,
and is separated from it by the tendon of the
pectinaeus muscle, the first perforating artery
passing below that tendon, while the circumflex
artery runs superior to it."

4. The second perforating artery is generally
the largest of those vessels: it arises a short
distance below the first, and passes through
both the adductors brevis and magnus ; it then
divides, like the former, into ascending and de-
scending branches : the former are distributed
to the glutreus maximus, the vastus externus,
and the tensor vaginae, likewise anastomosing
with the first perforating, the glutceal, sciatic,
and circumflex arteries: the latter are distri-
buted to the biceps, semi-membranosus, and
semi-tendinosus, the vastus externus, and the
integuments of the back of the thigh, and in-
osculate with the inferior perforating and with
branches of the popliteal artery. The artery
also gives branches to the adductor muscles
and to the sciatic nerve and the nutritious artery
of the femur, which enters a canal to be ob-
served in the linea aspera, at the junction of
the first and second thirds of the thigh, leading
obliquely upward into the bone. The second
perforating artery at times does not pass
through the adductor brevis, but when the first
does so, it generally runs inferior to it, perfora-
ting the adductor magnus only.

5. The third perforating artery is smaller
than either of the former, and arises lower
down ; according to Harrison, at the upper
edge of the adductor longus muscles, it passes
through the adductor magnus, and divides in
the same manner as the others : its branches
are also similarly distributed, and anastomose
with the second perforating artery from above,
and with branches of the popliteal from below.

When a fourth perforating artery exists, it
pursues a similar course and is distributed
similarly to the last. The perforating branches
of the profunda are subject to much variety
with regard to number, size, and precise course
and distribution ; so much so that they hardly
admit a definite description : the preceding ac-
count has been taken from a comparison of the
most approved authorities with the subject, in
order, as far as possible, to embrace their nu-
merous irregularities.

Beside those branches, which have been
enumerated, to which proper name have Keen
given, the profunda artery gives off during its

FEMORAL ARTERY.

249

course others less regular and less considerable,
which are distributed to the muscles in its
vicinity. Those are a branch to the pectinalis
and adductor muscles, and one or more to the
vastus internus and cruraeus muscles : it has
been elsewhere stated that the descending
branches of the external circumflex, destined
to the last-named muscles, and one of those to
the vastus externus, at times also arise from the
profunda itself. After having given off the last
perforating artery, the profunda, very much
reduced in size, continues its descent behind
the adductor longus muscle, inclining at the
same time outward, and external to the femoral
artery : it passes through the adductor magnus
a little above the passage of the femoral into
the ham, giving it small branches; then tra-
verses the origin of the short head of the biceps,
giving it also branches ; and, lastly, enters into
the outer part of the vastus externus, through
which it descends frequently to near the knee,
distributing branches to the muscle, and anasto-
mosing with the descending branches of the
external circumflex and with the external arti-
cular artery. The termination of the profunda
is by some* called the fourth perforating
artery.

The profunda resembles very much in its
course and termination the superior profunda
or musculo-spiral branch of the brachial artery,
to which it may be considered analogous.

Immediately before the femoral artery passes
into the popliteal space, it gives off its fifth and
lowest branch. This is usually called the
anastomotica magna artery, but there being no
more reason to apply the epithet anastomotic
to it than to the other branches of the femora,
and the great anastomotic artery of the thigh
being in reality the profunda, the name given
to it by Tiedemann seems much to be preferred,
viz. superficial superior internal articular.
It arises from the front of the femoral at the
inferior part of its last stage, and immediately
escapes from within the femoral canal, passing
through its anterior wall at the same time with
the saphenus nerve, as the femoral itself is
about to pass into the ham. Having come
through the aponeurosis forming the wall of the
canal, it descends for some distance toward the
inside of the knee parallel to the tendon of the
adductor magnus and anterior to it in company
with the saphenus nerve, and covered by the
sartorius muscle. After a short course it divides
into two branches. One of these runs down-
ward and forward, in front of the adductor
magnus, toward the patella ; enters the vastus
internus and traverses it in its course ; divides
within it into two branches, of which one runs
between the muscle and the bone, and supplies
the periosteum of the femur and the capsule of
the articulation, anastomosing at the same time
with the deep articulars ; the other continues
its course through the vastus, supplying the
muscle, until it reaches the side of the tendon
of the extensors : it then becomes superficial to
the tendon, and descends upon the front of the
patella, ramifying freely upon it, supplies the

* Scarpa, op. cit. p. 17, 18.

integuments and other superficial structures of
the articulation on its anterior part, and com-
municates freely with the other articular arte-
ries.

The second branch, into which the superfi-
cial articular divides, descends posterior to the
tendon of the adductor, in company with the
saphenus nerve, and covered by the sartorius :
as it descends, it gives branches to the ham-
string muscles, the semi-membranosusandsemi-
tendinosus, and also to the sartorius : when it
has reached the inner side of the knee, it divides
into two, of which one passes forward beneath
the aponeurosis, upon the internal condyle of
the femur, divides into branches which supply
the superficial structures of the joint upon its
inside, can be traced forward beneath the pa-
tella, and form free communications with the
other articular arteries, more particularly with
the inferior internal one : the second descends
to the leg, escapes from beneath the tendon of
the sartorius, and then, turning forward, rami-
fies over the internal surface of the tibia below
its tubercle, supplies the insertions of the mus-
cles and the coverings, and communicates with
branches of the internal articular and of the
tibial recurrent arteries. The superficial supe-
rior internal articular artery is variable in size :
at times it is of very considerable magnitude ;
at others it is small, or even absent altogether,
its place being supplied by a branch of the
popliteal artery. Its distribution also varies
with its size, the extent of the former being
proportioned to the latter.

The course of the artery diverges but little
from that of the femoral, and the relation of the
saphenus nerve to it is almost the same as that
which the nerve holds to the latter vessel :
hence, when the branch is large, it is liable to
be mistaken in the operation of tying the main
vessel, particularly in case of wound of the
arteiy, for the femoral itself. The description
of the articular artery here given has been
taken from the plate of Tiedemann, in which
the vessel is represented with its most extended
distribution.

The femoral artery also gives off, during its
descent through the thigh, beside the branches
which have been described, several others to
the muscles which are in its vicinity ; above, it
sends branches to the sartorius, iliacus, and
pectinalis ; and in the middle of the thigh to
the vastus internus on the one hand, and to the
adductor muscles on the other. Those branches
are for the most part inconsiderable in size,
and have not received names, but they are de-
serving of attention, inasmuch as they coope-
rate in the collateral circulation, more particu-
larly the second set, through which the femoral
artery is generally preserved pervious, after
ligature below the origin of the profunda, during
a greater or less extent of the interval between
the ligature and the popliteal artery, by means
of the anastomoses between the branches in
question and the circumflex arteries.

The adequacy of the collateral circulation in
the thigh to the maintenance and nutrition of
the limb after the interruption of the femoral
artery, has been so long established that it is

250

FEMORAL ARTERY.

at present unnecessary to insist upon it. But
the channels through which the circulation of
the blood becomes in such cases restored, as
well as the relations of the new circulation, are
deserving of attention.

The collateral connections of the femoral
artery are distinguishable into those between it
and the arteries of the trunk, those between it
and the popliteal and arteries of the leg, and
those between different parts of its own course.

The communication of the femoral artery
with the arteries of the trunk are established
between it and both the internal and the external
iliacs.

Those with the internal iliac are formed, 1 .
by means of the inosculations of the branches
of the profunda, the circumflex and perforating
arteries with the obturator, glutoeal, and sciatic
arteries, all branches of the latter; 2. by those
between the internal and external pudics ; and,
3. by the communications of the ilio-lumbar
artery with the deep anterior iliac, by which the
blood may be transferred to the superficial an-
terior iliac or the external circumflex.

From the obturator artery the blood is transmit-
ted through theascending branches of the internal
circumflex : this channel of communication be-
comes, in cases of interruption of the external
iliac artery, remarkably free, the branches esta-
blishing it being much enlarged and tortuous :
instances and representations of it may be
found in the Medico-Chirurgical Transactions,
vol. iv. and in Guy's Hospital Reports, IV o. 1,
Jan. 1836, from the experience of Sir Astley
Cooper.

Through the glutoeal artery the femoral com-
municates with the internal iliac by the inoscu-
lations between that vessel, the posterior tro-
chanteric and the ascending terminal branches
of the internal circumflex, and by those between
it and the ascending and circumflex branches
of the external circumflex artery : those connec-
tions are displayed also in the works just
referred to.

The communication of the femoral with the
internal iliac through the sciatic artery is esta-
blished by the anastomosis of that vessel with
the internal circumflex and the perforating arte-
ries, for which also see the same works.

The alteration in the condition of the sciatic
artery or its branches caused by ligature of the
femoral or of the external iliac artery presents
one of the most remarkable results of that cir-
cumstance : its branch to the sciatic nerve be-
comes greatly enlarged, very tortuous, and so
much elongated as to form at times a commu-
nication between the sciatic artery and the
posterior tibial. The connections established
through the pudic and ilio-lumbar arteries are
set forth, in the event of a case of ligature of the
external iliac artery published in the Medico-
Chirurgical Transactions, vol. xx. by Mr.
Norman.

The femoral artery communicates with the
external iliac through means of the anastomoses
between the anterior iliac arteries, internal and
external, between the internal anterior iliac and
the external circumflex ; and also by those be-
tween the superficial and internal epigastrics.

By the communications, which have been
mentioned, the transmission of blood through
the femoral artery may be restored, after the
interruption of the external iliac artery, or of
the femoral above the origin of the profunda,
with sufficient freedom for the perfect nutrition
of the limb ; of which numerous instances have
been observed by different writers.

The upper and lower parts of the femoral
artery are also connected by collateral channels.
Those are established by the communications
which exist between the branches of the pro-
funda artery arising from the upper extremity
of the femoral, and branches of the latter given
off during its course or from its lower extre-
mity ; thus the blood may pass from the femo-
ral artery above into the middle part of the
vessel through the anastomosis existing between
the descending branches of the external circum-
flex artery, and the branches given by the femo-
ral to the vastus internus muscle about the
middle of the thigh.

A similar communication exists upon the
internal side of the femoral by means of the
anastomoses by which descending branches of
the internal circumflex are connected with those
given by the femoral itself to the adductors.

The collateral connection of the femoral with
the popliteal artery is established through two
channels: 1. through the anastomoses between
the branches of the profunda, as well the ex-
ternal circumflex as the perforating arteries,
with the branches of the popliteal; whence
the femoral may be interrupted at any part
below the origin of the profunda, and the
blood thus find a ready passage from it into
the popliteal : 2. through those of the branches
given by the femoral to the vastus internus and
the superficial superior internal articular with
the same.

To the channels of communication which
have been described are to be added, as
pointed out by Scarpa, those established, by
the arteries of the periosteum and of the in-
ternal structure of the femur, between the
main arteries above and below. The former
are well represented by Scarpa,* and are formed
by anastomoses between branches of the external
circumflex, the profunda, the femoral and the
popliteal distributed to the periosteum.

Upon a review of the anastomotic con-
nections of the femoral artery, its course pre-
sents two stations at which communications
are established, on the one hand with the
main artery above, and on the other with that
below, while in the interval they are connected
the one with the other. Those are, 1. the first
part of the vessel's course from its commence-
ment to below the origin of the profunda;
and, 2. its lower part for so much of it as
includes the origins of the branches to the
triceps crural and adductor muscles, and the
superficial superior internal articular.

Again, it appears that through the first
station, not only is the femoral connected with
the arteries of the trunk and with the lower
part of the vessel, but also it is connected

* Reflexions sur I'Aneurisme, tab. ii.

FEMORAL ARTERY.

251

without the intermedium of the second with
the popliteal artery, the latter forming by much
the more free channel of communication be-
tween the two vessels, whence the circulation
of the lower part of the limb may be pre-
served independent of the communication be-
tween the upper and lower parts of the femoral
artery, as has been exemplified in the case of
Sir A. Cooper given in the Medico-Chirur-
gical Transactions, vol. ii.; and, lastly, a com-
munication exists by which the blood may be
conveyed from the arteries of the trunk into
the popliteal artery and the arteries of the leg,
independent of the femoral and without trans-
mission through any part of its canal.

Hence varieties may be expected in the con-
dition of the femoral artery in cases of inter-
ruption, according to the situation of the
interruption, and the influence of it or other
circumstances in determining the course which
the circulation is to take.

When the artery is obstructed above the
origin of the profunda independent of aneu-
rism, the origin of that vessel being free from
disease, it would appear that the trunk of the
femoral does not undergo any alteration in its
capacity, at least from the origin of the pro-
funda downward : when an interval exists
between the point of interruption and the
origin of that vessel, the trunk may be di-
minished for so much, while again it may
continue unaltered ; thus in Sir A. Cooper's
case* already referred to, the vessel was found
reduced to about half its natural size between
the origins of the epigastric and circumflex
ilii arteries and that of the profunda, and from
the latter it preserved its ordinary size through
the remainder of its course : in Mr. Norman's
casef on the other hand, it was of its natural
size in the interval adverted to, but inasmuch
as the origin of the profunda was obstructed
in the latter case, it cannot be considered so
fair an instance of the influence of the simple
interruption at the part specified as the former,
in which the femoral artery remained pervious
after the cure of the aneurism. It is hence to
be inferred, 1. that interruption of the femoral
above the origin of the profunda or of the
external iliac artery is not necessarily followed
by obliteration of the former, unless it be of
so much of the femoral as might intervene
between the interruption and the origin of the
profunda, where the ligature has been applied
to the former: 2. that in such case the internal
iliac is thenceforward the principal source from
which the supply of blood to the lower extremity
is to be derived ; and that the profunda artery
through its inosculations with the branches of
the internal iliac, constitutes the chief channel
through which the transmission of the blood
to the trunk of the femoral and the limb takes
place: 3. that the external iliac artery con-
tributes, but in an inferior degree, to the sup-
ply of the limb, when the interruption is in
the femoral itself: 4. that the femoral artery
and its branches thenceforward are to be con-

* Guy's Hospital Reports,
t Med.-Chir. Trans, vol. xx.

sidered branches of the iliac arteries, rather of
the internal than of the external, the trunk of
the femoral itself being secondary to its own
branches, by which the blood is transmitted
into it from the iliacs.

When the interruption of the femoral occurs
below the origin of the profunda, the oblitera-
tion of the trunk is no farther necessary than
between the interruption and the origin of the
profunda on, the one hand, if no other branch
intervene, and that of the next considerable
branch upon the other. In such case the pro-
funda artery becomes the main channel of the
circulation through the lower extremity from its
origin downward, and the femoral with its
branches thenceforth are to be regarded as
branches of it.

But when the interruption arises from aneu-
rism and the operation necessary for its cure,
obliteration of the femoral, to a greater or less
extent according to the case, for the most part
ensues : this appears to depend upon the in-
fluence, which the mode of cure of the disease
exerts upon the circulation through the vessel,
for the coagulation of the contents of the sac
being generally produced by the interruption
of the current of blood, the passage through
the sac becomes obstructed, and along with it
an extent of the artery upon both sides of the
seat of the aneurism greater or less according
to the disposition of the adjoining branches.
The extent to which the obliteration of the
artery has been found to proceed, has been
different in different cases, but the varieties
observed have been the following: 1. As re-
gards that part of the vessel which is above the
ligature, when the femoral artery has been
lied below the origin of the profunda for po-
pliteal aneurism, the vessel has been found,
when the ligature has been applied to the
lower part of the artery, either obliterated
from the ligature to the origin of the pro-
funda, as occurred in the first subject upon
whom Mr. Hunter* operated for popliteal aneu-
rism according to his method, or obliterated
upward only as far as the origin of those mus-
cular branches of the artery, which arise below
the profunda and anastomose with the articular
arteries. 2. When the ligature has been ap-
plied near to the origin of the profunda, as in
the operation of Scarpa, between it and the
origin of the branches alluded to, the artery
has been found obliterated from the point of
interruption to the origin of the profunda.

The condition of the artery below the seat
of the ligature is equally subject to variety
according to circumstances, and is still more
deserving of attention than the former : it has
been found in one of three states, either ob-
literated throughout from the origin of the
profunda down to the extremity of the popli-
teal artery, as occurred in the case reported
by Sir A. Cooper in the Medico-Chirursical
Transactions, vol. ii., or pervious throughout
from the point of application of the ligature
to the seat of the aneurism, where it was

* Transactions of a Society for the improve-
ment of Medical and Chirurgical Knowledge,
vol. i.

252

FEMORAL ARTERY.

obliterated. Of this condition several in-
stances are cited by Hodgson,* and a most
remarkable one is in the possession of Mr.
Adams of this city, through whose liberality
the author is permitted to introduce a notice
of it. It was obtained from a patient who had
been operated on by the late Professor Todd,
and is remarkable, 1. because the operation
had been performed upon both limbs, and the
condition of both is, as nearly as may be, the
same ; 2. because the obliteration at the seat
of the ligature does not on either side exceed
an inch, on one not being more than half that
length ; and, 3. because the artery is pervious
on both sides from the obliteration of the
ligature to the lower part of the popliteal
artery, the obliteration at the seat of the dis-
ease appearing not to have extended beyond it;
and being, on both sides, about two inches
long. Thirdly, the artery has been found par-
tially and irregularly obliterated, the vessel
being closed at and for some distance below
the seat of the ligature ; being then pervious,
the blood being conveyed into it by the in-
osculations between the minor branches of the
artery arising below the interruption and those
of the profunda from above ; and again im-
pervious below, the blood being conveyed
from it by similar branches anastomosing with
the articular arteries.

The effect of ligature of the external iliac
upon the femoral artery, independent of the
influence of aneurism, has been already ad-
verted to. That effect is liable to be modified
by the presence of the disease ; thus in a case
related by Sir A. Cooper in the fourth volume
of the Medico-Chirurgical Transactions, in
which the iliac was tied for aneurism of the
femoral artery at the middle of the thigh, the
latter vessel was obliterated from the origin
of the profunda downward. The case, re-
corded by Mr. Norman, already referred to,
in which the external iliac was also tied,
presents another remarkable modification : in
it the femoral remained pervious, but the root
of the profunda was obliterated, while its
branches were open.

Operative relations of the femoral artery. —
The femoral artery may be the subject of ope-
ration at any part of its course, there being
nothing either in its situation or relations to
forbid the exposure of it at any point, if cir-
cumstances should require it. All parts, how-
ever, are not equally eligible, the vessel being
in some situations more deeply situate, covered
by a greater number and depth of parts, and
its relations more complicated than at others.
It has been taken up in each of the three
stages into which its course has been divided,
and the operations, which may according to
circumstances be performed upon it, may with
advantage be referred to those. The propriety
of thus distinguishing them will appear in a
strong light, when those modifications, which
the anatomical relations of the vessel may
justify, shall have been discussed, as also from
the history of the operations, which have been

* Op. cit. 278, 9.

and are proposed to be performed upon the
femoral artery.

In its first stage the vessel may be tied
at two points, viz. either above or below the
origin of the profunda artery : the operation
at the former point, being performed under
circumstances different from those in which
that at the latter is admissible, may be con-
sidered apart from the others, and the de-
tail of it be postponed until they have been
disposed of; while the operation in the second
case, and those in the second and third stages
have been at different times performed for the
same purpose — the cure of popliteal aneurism
— and therefore a comparison of their several
details and advantages merits attention. The
situation in which the femoral artery was first
taken up for popliteal aneurism is the third
stage of its course : here it was tied, as is
generally known, by J. Hunter. In his ope-
ration Hunter made " an incision on the an-
terior and inner part of the thigh rather below
its middle ;" i. e. in the third stage ; " which in-
cision was continued obliquely across the inner
edge of the sartorius muscle and made large :"
the other steps of his operation it is not neces-
sary at present to particularize ; the author
would only remark, as a matter of history, that
Hunter's application of ligatures has been mis-
understood : he applied in his first operation
four ligatures to the artery, and it is com-
monly, if not generally, said that they were
drawn with various degrees of tightness ; but
such was not the case, they were tied all
equally tight : the account given in the report
of the operation being, " the artery was now
tied by both these ligatures/7 viz. the two upper,
" but so slightly as only to compress the sides
together. A similar application of ligatures
was made a little lower. The reason for hav-
ing four ligatures was to compress such a
length of artery, as might make up for the
want of tightness, it being wished to avoid
great pressure on the vessel at any one part."

The artery may be and has been frequently
taken up in the middle stage, and the ope-
ration, as described in several surgical works,
will be found to belong to, if not to be in-
tended for, that stage. During its two latter
stages the artery is covered by the sartorius :
in its uppermost it is not covered by the muscle,
and consequently if it be necessary to displace
the muscle to bring the artery into view above
the last stage, it must be in the middle one,
and in the account of the operation given by
some of the highest authorities, the displace-
ment of the sartorius is stated as one of the
steps. This the author refers to not in a spirit
of criticism, but in order to mark more
strongly the distinction between the operations
at the several stages, and to direct attention to
the advantages possessed by that in the first
over the others ; more particularly since de-
scriptions, which in strictness apply to the
operation in the middle stage, and at a part
of the aitery's course below the first, may be
found so put forward that the operations at the
two points must be confounded ; and thus the
advantages contemplated by the proposer of

FEMORAL ARTERY.

253

the latter be lost. It will be recollected that
in the two inferior stages the artery is covered
by the sartorius and by two laminae of the
fascia lata, between which the muscle is
situate : the vessel is, therefore, similarly cir-
cumstanced in this particular throughout both,
but in some other important respects the re-
lations of the artery are different, l. In its
middle stage the vessel is nearer to the anterior
plane of the limb. 2. The deep layer of fascia,
by which it is covered, is far less thick and
strong, particularly at its upper part. 3. The
artery is not so completely covered by the sar-
torius; and for those reasons the vessel may
be more easily reached from before. These
constitute the principal anatomical conside-
rations why the middle stage should be pre-
ferred to the lower for operation, but, since it
is at times requisite to tie the vessel in its last
stage, it is necessary to examine the influence
which its anatomical relations may have upon
the conduct of the operation at that part.
1. The greater depth of the artery from the
anterior surface of the limb renders a more
extended incision necessary : in cutting upon
arteries " the centre of the incision should be,"
as directed by Guthrie, " if possible directly
over that part of the artery on which it is in-
tended to apply the ligature." In the case of
the femoral artery in its third stage, the length
of the incision should not be less than from
four to five inches according to the volume of
the limb; its direction should correspond to
that of the sartorius, but it must be varied
somewhat according to the side of the muscle
upon which the operator may purpose to seek
the vessel. It should commence somewhat
below the middle of the thigh, and be con-
tinued as much upon the lower as upon the
middle third of the limb. 2. The artery is
situate, in its third stage, nearer to the outer
than the inner margin of the sartorius, and the
more so the nearer to its termination ; hence it
may be exposed with greater ease and cer-
tainty by cutting upon the outer edge of the
muscle and displacing it inward. Hunter, in
his operations, selected the inner margin, and
displaced it forward and outward; but this
proceeding is attended with disadvantages.
1. The sapher.a vein is more in the way and
exposed to danger of being divided since it
lies at this part, along or near the inner mar-
gin of the sartorius. 2. The muscle lying more
to the inner than the outer side of the artery
must be more displaced, and the depth of the
wound for the same reason greater when the
vessel is sought from its inside.* 3. The ope-
ration must be more inconvenient and em-
barrassing, as well because of the former
difficulties as because it must be performed
more from the inside of the limb, and from
within outward, than in the method by the

* The contrary is maintained by Lisfranc and
others ; but, according to the experience of the
author, without sufficient reason. He has care-
fully compared the depth of the wounds as made
upon the opposite sides of the muscle, and in the
subjects of examination that by the inside appeared
to him the deeper.

outer margin of the sartorius. Those objec-
tions are avoided by cutting upon the outer
edge of the muscle, against which, however,
it has been advanced that in that method the
vastus internus may be mistaken for the sar-
torius, and that the wound being made from
before, there is not a depending and ready
outlet afforded to matter should it form, while
by the other there is. The former of these
objections cannot carry much weight, and for
the second the best plan for obviating the
dangers of inflammation and suppuration is,
as much as possible, to render them unneces-
sary, which is best accomplished by selecting
that method by which the artery may be ex-
posed most easily, and with least disturbance
to the parts in its vicinity. To the writer,
therefore, it seems that the method by the
outer margin of the sartorius, which appears
to have been suggested by Hutchison, is the
more eligible in the operation for taking up
the femoral in its third stage. 2. The great
thickness and strength of the anterior wall
of the femoral canal both increase the dif-
ficulty of opening the canal, and render it
desirable that that structure should be freely
divided for the double purpose of facilitating
the taking up of the artery, and preventing
the injurious effect which must be produced
by the confinement caused by the structure in
question in the event of inflammation extend-
ing along the vessel. 3. The relation of the
vein to the artery at this part, viz. posterior
and external, will make it more safe to pass
the needle round the latter from without than
from the outside ; this, however, is a rule
which cannot be strictly adhered to, for the
direction in which the instrument shall be
passed must be varied according to circum-
stances; it would be difficult to pass it from
the outside in case the artery were exposed
from the inside of the sartorius ; but attention
to the caution demanded by the position of
the vein is, for this reason, only the more
necessary. 4. The saphenus nerve being here
within the femoral canal is to be carefully
avoided ; it will be so with certainty, if the
needle be earned from the outside. 5. The
mistake of confounding the superficial supe-
rior internal articular artery with the femoral
must be also avoided.* This mistake, which
has occurred, ought not however to occur
again in the hands of a well-informed surgeon,
for the possibility of it ought not to be lost
sight of in operations at the lower part of the
thigh ; and it may be easily avoided by re-
collecting, first, that the femoral itself is
within the femoral canal, and therefore that
any vessel, which presents before the division
of the anterior wall of the canal, which is so
remarkably thick in this situation that it can
hardly be overlooked, cannot be the one which
is sought for; and, secondly, that the course of
the branch within the canal, after its origin, is
very short, and therefore that in case of doubt
the vessel which presents, must, if the arti-
cular, conduct us directly to the trunk itself,

* See that vessel.

254

FEMORAL ARTERY.

when followed upward for a very short dis-
tance.

Lastly, the structures to be divided or put
aside in order to expose the artery are, — 1 . the
skin; 2. the subcutaneous cellular stratum;
3. the superficial lamina of the fascia lata,
forming the anterior wall of the sheath of the
sartorius ; 4. the sartorius itself; 5. the deep
lamina of the fascia forming the posterior wall
of the sheath of the sartorius, and the anterior
wall of the femoral canal ; and, 6. the proper
sheath of the vessels.

The difference between the anatomical re-
lations of the operation in the middle and
inferior stages of the artery depends upon the
modifications to be observed in the relations
of the vessel at the two points, and also in
some of the parts concerned. The number
and order of the structures interposed between
the surface and the artery are the same as in
the third, but their disposition and relations
differ in some important particulars so much
as to authorize a difference in the proceedings
to be adopted, and to justify a preference in
favour of the former. 1 . The artery is nearer
to the anterior surface of the limb, and the
more so the nearer to the commencement of
the stage : it is therefore more easily reached
and in the same proportion. 2. It is nearer
to the inner than the outer margin of the sar-
torius, and, in like manner, the more so, the
nearer to its upper extremity ; and hence it
may be brought into view with more ease and
with less disturbance of the muscle by dis-
placing its inner margin outward, than its
outer inward.

The latter proceeding is advocated by Hut-
chison for the purpose of avoiding the sa-
phena vein and the lymphatics. That the
vein will be effectually secured from danger
by cutting upon the outside of the sartorius
will be at once admitted ; but it appears to the
author that the advantage contemplated will
be more than counterbalanced by the dis-
advantages attending it, and on the other hand
that the proceeding is not necessary: for, 1.
if the outer margin of the muscle be cut upon
in the middle of the vessel, the incision must
be made considerably external to the line of
the artery's course, and thereby the guide to
the vessel otherwise afforded by that line must
be lost, and uncertainty and consequently
embarrassment be likely to ensue in seeking
for the artery after having displaced the muscle.
2. Much more disturbance and violence are
likely to be inflicted upon the artery and the
adjoining parts by the plan in question, in-
asmuch as the vessel is so much nearer to the
inner than the outer margin of the muscle ;
in consequence of which the muscle must be
displaced to a much greater extent in proceed-
ing from without inward, and the obstruction
offered by it to the performance of the other
steps of the operation must lead to greater
violence either to the artery or to the muscle ;
and afterward a valvular wound must be left,
a circumstance very unfavourable in the event
of the occurrence of inflammation and sup-
puration in the vicinity of the track of the

vessel, and those objections are the stronger
because the artery is usually sought at the
upper part of the stage, where it is but little
overlapped by the muscle. On the other hand
the saphena vein ought not to be endangered
in the operation, for it is situate so far internal
to the artery that the incision ought not to fall
upon it. The case is different from that of cut-
ting upon the inner margin of the sartorius
during the third stage of the vessel ; for there
the vein is for the most part close to the edge
of the muscle, and the wound must be in-
clined in depth from within outward, by which
direction the vein is interposed between the
surface and the artery ; whereas, in the second
stage, whether the operator, in proceeding by
the inner margin of the muscle, cut directly
upon the artery's course or upon the edge of
the sartorius, there is sufficient space between
it and the vein to leave the latter safe. The
course of the artery may be crossed at any part
by the superficial femoral veins, as has been
explained, and they, if they present, will be
in danger of division ; but this inconvenience
would not be removed by the plan in question,
whereas both it and the danger to the saphena
may be avoided by an easier and less ob-
jectionable proceeding than that of cutting
upon the outer edge of the sartorius, viz. 1.
by ascertaining, through means of pressure,
the situation and course of the veins ; and, 2.
by proceeding with somewhat more caution,
where there is reason to expect their presence,
dividing first only the skin and continuing the
incision through the subcutaneous structure,
not by a single stroke, by which the vein if in
the way must necessarily be divided, but gra-
dually, until the vessel has been exposed and
drawn aside. It seems therefore to the author
not only unnecessary, but very objectionable
to cut upon the outer margin of the sartorius,
in exposing the femoral artery above the mid-
dle of the thigh. 3. The anterior wall of the
femoral canal is much thinner than in the
third stage, and therefore more easily ma-
naged. 4. The vein is directly behind the
artery, and therefore the needle may be passed
with equal safety from either side, according
to circumstances : in operating by the inner
margin of the sartorius it will be more easily
done from the inside : the position of the vein
and its close connection to the artery render
it especially necessary that the extremity of
the needle be kept in contact with the artery
in being carried behind it. The saphenus
nerve requires the same attention as in the
third stage.

But the situation in which it is at present
generally considered most eligible to expose
the artery for the application of a ligature, when
circumstances do not forbid a choice, is that
recommended by Scarpa, viz. in the upper
third of the thigh, and in the first stage of the
artery's course as described in the account of
the anatomical relations of the vessel. In his
description of the details of the operation,
Scarpa directs thus : " The surgeon pressing
with his fore-finger will explore the course of
the superficial femoral artery, from the crural

FEMORAL ARTERY.

255

arch downward, and when he comes to the
place where he does not feel any more, or very
confusedly, the vibration of the artery, he will
there fix with his eye the inferior angle or ex-
tremity of the incision which he proposes to
make "for bringing the artery into view. This
lower angle of the incision will fall nearly on
the internal margin of the sartorius muscle,
just where this muscle crosses the course of the
femoral artery. A little more than three inches
above the place pointed out, the surgeon will
begin his incision and carry it along the thigh
in a slightly oblique line from without inwards,
following the course of the femoral artery as
far as the point fixed with the eye." By this
incision the skin and cellular substance are to
be divided, and the fascia lata exposed, " then
with another stroke of the bistoury, with his
hand free and unsupported, or upon a furrowed
probe, he will divide along the thigh, and in the
same direction as the external wound the fascia,
and introducing the fore-finger of his left hand
into the bottom of the incision, he will imme-
diately feel the strong beating of the artery, and
this without the necessity of removing the in-
ternal margin of the sartorius from its position,
or at least very little. With the point of the
fore-finger of the left hand already touching the
artery, the surgeon will separate it from its
lateral connexions and from the vein;" after
which the ligature is to be carried round it by
means of a blunt aneurism-needle. The author
has introduced the preceding account in order
to fix the precise situation of the operation as
performed by Scarpa, because it appears to him
that it has been to a certain degree lost sight of,
and also to direct attention more strongly
to the advantage proposed by that distin-
guished surgeon in the adoption of the method
which he has recommended. A very brief
consideration of the descriptions given by se-
veral writers* of the proceedings to be adopted
in the operation of taking up the artery in the
upper part of the thigh will suffice to shew
either that Scarpa's method has been con-
founded more or less with the operation at a
lower point, or that its advantages have been
disregarded: thus, while it is stated that the
part of the limb in which the femoral artery
can be tied with the greatest facility is between
four and five inches below Poupart's ligament,
and which is Scarpa's point,-)- the displacement
of the sartorius is accounted a part of the ope-
ration, and it has even been debated whether
the incision should not be made on the outer
edge of the sartorius, and the artery exposed
by drawing the muscle inward ; but the dis-
placement of the sartorius is not only not a
necessary part of Scarpa's plan, but is that
particular the avoidance of which he proposed
to himself by the method he selected ; from
whence it will appear that the operation, as
described in the accounts alluded to, refers,
strictly speaking, to the second and not to the
first third of the vessel's course, within the
latter of which it must be performed in order

* Hodgson, &c.

t The distance at which the sartorius crosses the
artery varies according to the stature.

to avoid the sartorius. The structures to be
divided in this operation are, 1. the skin, 2.
the subcutaneous cellular structure, 3. the
fascia lata, forming the anterior wall of the
femoral canal. The extent of the superficial
incisions need not exceed three inches, com-
mencing above either according to the rule of
Scarpa or about two inches below Poupart's
ligament : the direction in which they should
be made ought to correspond as nearly as pos-
sible with the course of the artery. The extent
to which the fascia lata is to be divided is
stated differently by different writers : by some
it is directed to be divided to the extent of
about an inch : the direction of Scarpa is not
precise upon the point in the text, though it is
plain that he intended it should be divided to
a much greater length than an inch, but in a
note it is strongly insisted that the division of
the fascia should correspond in extent to that
of the external wound. Two reasons present
for this : 1. greater facility in the performance
of the operation, and less disturbance in con-
sequence to the artery; 2. the avoiding the
injurious effects which must be produced by
the confinement consequent upon too limited
a division of the fascia in the event of the
supervention of inflammation. It cannot be
doubted that a division of an inch is altogether
too short to meet those considerations, and that
the fascia ought to be divided to a greater ex-
tent ; on the other hand it does not appear that
advantage would be gained by so free a divi-
sion as that recommended by Scarpa ; and the
rule of Guthrie seems the best calculated to ac-
complish the ends in view : he advises the fascia
to be divided for the space of two inches. The
division may be effected either with or without
the assistance of the director. It will be well
to recollect here that, at the point at which the
sartorius is about to overlap the artery, a du-
plicature of the fascia takes place in order to
enclose the muscle, and hence that, if the
opening of the canal be attempted at the lower
extremity of the stage, and close to the muscle,
two layers of the fascia may require to be di-
vided before this purpose can be accomplished.
The femoral canal having been opened by the
division of the fascia lata, the next step in the
operation is the division of the proper sheath
of the vessels and the insulation of the artery.
Previous to this, should the internal genicular
nerve be found to cross the canal superficial to
the artery at the part, at which the vessel is
to be detached from the contiguous parts, it
should be separated and drawn outward. The
insulation of the artery Scarpa recommends to
be effected with the finger, raising the vessel
from the wound even along with the vein if
necessary; such a proceeding, however, must
be very objectionable, as inflicting great dis-
turbance and violence upon the artery. It is
to be recollected that in order to insulate the
artery it is necessary to divide or lacerate the
investment, which immediately encloses the
two vessels and connects them to each other,
and which has been elsewhere denominated
the femoral sheath ; this, though thin, is dense,
and is to be expected to offer resistance to the

256

FEMORAL ARTERY.

separation of the artery from the vein : the best
method of effecting this, as it seems to the
author, will be, after having opened the sheath
directly over the centre of the artery either by
a touch of the knife or first nipping up a part
of it with the forceps ; making an aperture
into it with the blade of the knife held horizon-
tally, and extending the opening upon a di-
rector to the length of " three-quarters or an
inch," as recommended by Guthrie ; then with
the forceps to take hold of each portion of the
sheath in turn and drawing it to its own side,
outward or inward as the case may be, to de-
tach the artery from it with the extremity of a
director or of the aneurism-needle, moving the
extremity of the instrument gently upward and
downward at the same time that the vessel is
carried, by means of it, in the opposite direc-
tion from the side of the sheath which is in
the forceps ; by this proceeding the artery may
be easily and safely insulated almost, if not
quite, round, and with little if any disturbance
to it. That done, the needle and ligature may
be carried round the artery: the performance
of this, which is the most delicate step in the
operation, will be found much facilitated by
the separation of the artery as recommended ;
in fact, little more will then remain than to
pass the needle, the passage having been al-
ready opened. In doing so it will be well to
hold the inner portion of the sheath, with the
forceps, inward and backward, by which the
vein will be drawn away from the artery, and
at the same time to insinuate the blunt extre-
mity of the aneurism-needle round the artery
from within outward, because of the situation
of the vein, moving it, if any obstruction be
encountered, upward and downward, while it
is also carried forward, and bearing the artery
somewhat outward with it at the same time ;
when the extremity of the needle has appeared
on the outside of the artery it may be liberated,
if necessary, by a touch of the scalpel upon it.
In the execution of this manreuvre two acci-
dents are to be avoided, viz. injury of the
vein, and inclusion of the saphenus nerve :
the close juxta-position and attachment of the
former to the artery render much care neces-
sary to leave it uninjured ; but the proceeding
recommended will, if carefully executed, cer-
tainly preserve it from being wounded. The
saphenus nerve is here on the outside of the
artery, and might be included within the liga-
ture if the extremity of the needle were carried
too far outward ; the operator should therefore
assure himself, before tying the ligature, that
the nerve has not been included ; but the risk
of this accident ought not to be great at this
part of the artery's course, certainly not so
much so as at a lower point, inasmuch as the
nerve has as yet hardly entered the femoral
canal, and is therefore separated from the ar-
tery by more or less of its outer wall; and with
the precautions recommended in insulating the
vessel and passing the ligature it will almost
certainly be excluded at every part : the possi-
bility of the accident is, however, not to be
lost sight of. The needle having been carried
round the artery, the ligature is to be taken

hold of with the forceps, and one end drawn
out, after which the needle is to be withdrawn.
The advantages of the part chosen by Scarpa
for this operation are numerous and obvious :
1. the artery is nearer to the surface and has
fewer coverings; there is therefore less to be
divided in order to bring it into view; 2. the
vessel being more superficial, its pulsations can
be more distinctly felt and its course ascer-
tained previous to operation, a guide wanting
in the lower parts of the thigh ; 3. " the ope-
ration is done/' as Guthrie observes, " on that
part of the artery which is not covered by
muscle, and all interference with the sartorius
is avoided : this method obviates all discussion
as to placing the ligature on the outside of the
muscle." The plan of cutting upon the out-
side of the sartorius in the upper stage of the
artery must be, if contemplated by any, a pro-
ceeding hardly defensible in the ordinary dis-
position of the muscle, for all the reasons ad-
vanced already against its use in the second
stage apply with much greater force to it in the
former case ; but it is at the same time to be
observed that the distance of the point at which
the muscle crosses the femoral artery is not ab-
solutely regular, and that great deviation in
this respect might render it necessary even to
cut upon the outer margin of the muscle in
order to expose the artery in the first third of
its course. The distance from Poupart's liga-
ment at which the muscle ordinarily crosses is,
according to the stature, from three and a half
to five inches, but it may in certain cases be
found to cross so much sooner that the artery
could not be exposed below the origin of the
profunda without displacing the muscle ; thus
Burns* mentions that he has seen, in conse-
quence of malformation of the pelvis, the artery
covered by the muscle, before it had reached
two inches below the ligament, and the author
has witnessed the same from retraction of the
thighs, consequent apparently upon long con-
finement to bed ; in the latter case it would
certainly have been more easy to expose the
vessel from the outer than from the inner side
of the muscle ; but such cases are to be re-
garded only as exceptions to be borne in mind,
but not to influence our general conduct.

4. The performance of the last and most deli-
cate parts of the operation must be much more
easy and less embarrassed, the interference of
the sartorius being avoided; while, on the other
hand, all apprehension on account of the pro-
funda is removed, since that vessel seldom, if
ever, arises farther than two inches from Pou-
part's ligament, and the course of the case after
operation is more likely to be favourable and
exempt from untoward occurrences, since much
less violence must be done, and the superven-
tion of injurious inflammation or its conse-
quences thereby prevented.

The operation for taking up the femoral ar-
tery above the origin of the profunda is not often
required, and, except in case of wound, may pro-
bably give place altogether to that of tying the
external iliac : it presents no advantage over

* Op. cit. p. 321.

FIBRINE.

257

the latter, it does not promise more successful
results : should secondary hemorrhage succeed
to it, there is little prospect that the ligature of
the iliac would afterward succeed, and the
uncertainty existing with regard to the point of
origin of the profunda raises a very strong ob-
jection against it, inasmuch as we cannot know
whether the origin of that vessel be above,
below, or at the point at which the ligature is
to be applied : it is further exposed to the
difficulty, before adverted to, which is likely
to arise in cases of high origin of the profunda,
in which that vessel may be taken for the
femoral, and thus another source of embar-
rassment be encountered.

In the performance of it the following struc-
tures will present : 1. the skin ; 2. the subcu-
taneous cellular stratum along with the inguinal
glands and the superficial inguinal vessels of
the latter : those which are most exposed to be
divided are the superficial epigastric and its
branches ; the superficial anterior iliac and the
superficial pudics may be encountered, but
they are less likely; 3. the superficial lamina
of the iliac portion of the fascia lata; and 4.
the prolongation of the fascia transversalis,
which forms the front of the femoral sheath.

An incision three inches long will suffice ; it
should commence above Poupart's ligament,
and be continued in the line of the vessel for
two inches below it.

If the superficial vessels bleed, on division,
so much as to interfere with the course of the
operation, they should be at once secured;
otherwise they will probably cease themselves,
and give no further trouble.

The lymphatic glands, if in the way of the
incisions, may be either held aside or removed.
The fascia lata and sheath may be treated in
the same manner as in the other operations
described ; they can be easily distinguished in
consequence of the thin stratum of fat which is
usually interposed.

The insulation of the artery and the passage
of the needle require the same precautions as
in the operations at other parts of the vessel's
course. The vein being placed along the inside
of the artery the needle should be passed from
that side.

The crural nerve and its branches are here
altogether safe, as they lie without the femoral
canal, but, as has been before pointed out, the
crural branch of the genito-crural nerve may
be included in the ligature ; it will be most
certainly avoided by the careful insulation of
the artery: the operator should also assure
himself, before tying the ligature, that no fila-
ment is enclosed.

Should two arteries present, as described in
the anatomy of the profunda, and a question
arise as to which is the femoral, the criteria
pointed out will enable the operator to decide
(see profunda artery ) ; and the difficulty will,
almost certainly, be altogether avoided by cut-
ting directly upon the centre line of the femoral
as ascertained by its pulsations.

Operation on the profunda artery. — From
the anatomical details it follows that in the ma-
jority of cases the profunda is situate, in the

VOL. II.

first stage of its course at least, at the outer or
iliac side of the femoral artery, though upon
a plane posterior to that vessel : it has also, at
the same time, the same coverings, differing
only in being contained in a sheath proper to
itself; and hence, if necessary, the profunda
might be reached in that situation by an opera-
tion similar to that for exposing the femoral
itself at the same place, in which much advan-
tage would be obtained by first exposing the
latter vessel, and following it as a guide to
the origin of the former ; which, if in its usual
situation, will be exposed by displacing the
femoral inward, and then the proper sheath of
the profunda should be opened to a certain ex-
tent, in order to allow the application of the
ligature at a sufficient distance from the origin
of the vessel. But in the inferior stages of its
course it may be laid down, as a general rule,
that it cannot be reached from the front of the
thigh, inasmuch as, with the exception of those
cases in which it is throughout external to the
femoral, and in which, from its deep position
and the want of a guide to its exact situation,
the rule will yet equally apply, it is not only
more deeply seated, but it is separated from
the anterior surface of the limb by the super-
ficial femoral artery, and by the femoral, pro-
funda, and circumflex veins, as well as by the
coverings of the femoral vessels, and lastly by
the adductor longus muscle. In any case, did
circumstances render necessary the attempt to
tie the profunda, it would be an operation in
which much uncertainty and difficulty must be
anticipated, in consequence of the varieties
presented by that artery in its origin and
course.

For Bibliography see ANATOMY (INTRODUC-
TION), and ARTERY.

(B. Alcock.)

FIBRINE, (Yr.fibrine; Germ. Faserstoff.)
Under this name physiologists and chemists
have generally described the animal proximate
principle constituting that part of muscular
fibre which is insoluble in cold water, and that
portion of the coagulum of blood which re-
mains after the removal of its colouring matter.

The fibrine of blood is best obtained by
stirring a quantity of fresh-drawn blood with a
piece of wood, to which the coagulum adheres,
and may afterwards be washed in large and
repeated portions of water till it loses its co-
louring particles, and remains in the form of
a buff-coloured, fibrous, and somewhat elastic
substance ; this may then be partially dried by
pressure between folds of blotting-paper, di-
gested in alcohol to remove fat, and then care-
fully dried, during which process it loses about
three-fourths of its weight, and becomes brittle
and of a yellowish colour: it is insipid and in-
odorous. In cold water it slowly resumes its
original appearance but does not dissolve:
when, however, it is subjected to the long-
continued action of boiling water it shrinks
and becomes friable, and a portion of a newly-
formed substance is at the same time taken up
by the water, which gives it a yellowish colour
and the smell and taste of boiled meat, and

s

258

FIBRINE.

which, when obtained by evaporation, is brittle,
yellow, and again soluble in water: this solu-
tion is rendered turbid by infusion of galls,
but the precipitate differs from that yielded by
gelatin, and appears to be a distinct product.
The insoluble residue has lost its original cha-
racters; it no longer gelatinises with acids or
alkalies, and is insoluble in acetic acid and in
caustic ammonia.

The action of acids and alkalies upon the
fibrine of blood has been studied in detail by
Berzelius and others ; the following is an ab-
stract of their results.*

All the acids, except the nitric, render fibrine
transparent and gelatinous : the diluted acids
cause it to shrink up. In sulphuric acid it
acquires the appearance of a bulky yellow jelly,
which immediately shrinks upon the addition
of water, and is a combination of the acid and
fibrine ; when well washed upon a filter it gra-
dually becomes transparent and soluble, and
in that state is a neutral sulphate of fibrine. It
is again rendered opaque by dilute sulphuric
acid, and is precipitated from its aqueous solu-
tion by that acid in the form of white flakes,
which appear to be a supersulphate. When
fibrine is heated in sulphuric acid, both are
decomposed, the mass blackens, and sulphu-
rous acid is evolved. If the colouring matter
has not been entirely washed out of the fibrine,
the sulphuric solution is of a brown or purple
colour.

Nitric acid communicates a yellow colour to
fibrine, and, if cold and dilute, combines with
it to form a neutral nitrate, analogous to the
sulphate When fibrine is digested in nitric
acid, nitrogen is evolved, and its composition
considerably changed, as we shall more parti-
cularly mention in describing the action of this
acid on muscular fibre.

Muriatic acid gelatinises fibrine and then
gradually dissolves it, forming a dark blue
liquid, or purple and violet, if retaining any
haematosin. This solution, when diluted with
water, deposits a white muriate of fibrine,
which, like the sulphate, gelatinises when the
excess of acid is washed away, and becomes
soluble, and is again thrown down from its
aqueous solution by excess of acid. The blue
liquid, after the separation of the precipitate by
dilution, retains its colour, but loses it when
saturated with ammonia, and with excess of
ammonia becomes yellow. Fibrine digested
in dilute muriatic acid is converted into the
same white compound as that precipitated
by water from the concentrated muriatic solu-
tion. Wrhen boiled in the acid, nitrogen is
evolved, and a solution is obtained, which, after
4he saturation of the acid, is precipitated by
infusion of galls, but not by alkali or ferrocy-
anuret of potassium ; on evaporating the solution
to dryness a dark brown saline mass remains,
so that the fibrine appears to have undergone
some decomposition.

* Berzelius, Lehrbuch der Thier-Chemie, Wbh-
ler's German translation. Dresden, 1831. See
also Medico-Chirurgical Transactions, vol. iii.
p. 201.

A solution of recently-fused phosphoric acid
acts upon fibrine in the same way as the sul-
phuric acid ; but if the acid solution has been
kept for some weeks, the fibrine then forms
with it a soluble jelly, which is not precipitated
by excess of acid.

Concentrated acetic acid converts fibrine into
a jelly easily soluble in warm water. When
this solution is boiled, a little nitrogen is evolved,
but nothing is precipitated ; when gently eva-
porated, it gelatinises, and leaves, on desic-
cation, an opaque insoluble residue. The other
acids added to this acetic solution produce
precipitates which are compounds of fibrine
with the added acid. Fibrine is also preci-
pitated from the acetic solution by caustic pot-
assa, but is redissolved by excess of alkali.

The acetic solution of fibrine is precipitated
in white flakes by ferrocyanuret of potassium :
this precipitate, when dried, appears to be a
compound of fibrine with cyanuret of iron
and hydrocyanic acid ; it is insoluble in dilute
acids, but is decomposed by caustic alkalis,
which abstract the cyanuret of iron and hydro-
cyanic acid, and the remaining fibrine first
gelatinises and then dissolves. 100 parts of
this compound, carefully dried at 167°, and
then incinerated in a weighed platinum cru-
cible, gave 2.8 red oxide of iron,=7.8 of the
combination of cyanuret of iron with hydro-
cyanic acid; whence it follows that 92.2 of
fibrine were contained in the white precipitated
compound.

Caustic potassa, even much diluted, dissolves
fibrine. If the solution is very dilute, the
fibrine gradually forms a bulky jelly, which,
heated in a close vessel to about 130°, dissolves
into a pale yellow liquid, not quite transparent,
and which soon clogs a filter. The yellow tint
appears to arise from the presence of a small
portion of adhering haematosin. When this
alkaline solution is saturated by muriatic or
acetic acid, it exhales a peculiar fetid odour and
blackens silver, announcing the presence of
sulphur, so that the animal matter seems to
have suffered some slight change. It is stated
by Berzelius that fibrine is capable of neutral-
izing the alkali, and that such neutral com-
pound may be obtained by dissolving the
fibrine in the alkaline solution, and adding
acetic acid till it begins to occasion a precipi-
tate ; the filtered liquid is then perfectly neu-
tral, but the potassa bears a very small propor-
tion to the fibrine. This neutral solution, he
says, much resembles white of egg, and is,
coagulated by alcohol and acids, though not by
heat. Gently evaporated, it gelatinises, and,
when dry, assumes the appearance of albumen
dried without coagulation. In this state it
dissolves in warm water, and is first thrown
down, and then redissolved by the acids when
added in excess. Alcohol throws down nearly
the whole of the fibrine from its neutral alkaline
solution : if there be excess of alkali, much of
the fibrine is retained. Mr. Hatchett found that
fibrine, when digested in strong caustic potassa,
evolved ammonia and yielded a species of soap;
acids occasion a precipitate in this solution
which is altered fibrine, for it neither gelati-

FIBRINE.

259

nises nor dissolves in acetic acid: ammonia acts
as potassa, but less energetically.

When fibrine is digested in solution of per-
sulphate of iron, or of copper, or of perchlo-
ride of mercury, it combines with those salts,
shrinks up, and loses all tendency to putre-
faction. When the alkaline solution of fibrine
is decomposed by metallic salts, the precipitate
consists of the fibrine in combination with the
metallic oxide; some of these compounds are
soluble in caustic potassa.

Tannin combines with fibrine, and occasions
a precipitate both in its alkaline and acid solu-
tions : the tanned fibrine resists putrefaction.

The ultimate composition of fibrine has been
determined by Gay Lussac and Thenard, and
by Michaelis, who made a comparative ana-
lysis of that of arterial and venous blood : the
following are their results: —

Gay Lussac Michaelis.
and Thenard. Arterial. Venous.
Nitrosen ..19.934...
Carbon ..53.360...
Hydrogen 7-021...
Oxygen . .19.685 23.785 24.065

.17.587 17.267

.51.374 50.440

7.254 8.228

100.000 100.000 100.000

The mean of these results gives nearly the fol-
lowing atomic composition: —

Atoms. Equivalents.

Nitrogen 1 14 ....

Carbon 6 36....

Hydrogen 5 5

Theory.
..19.72
..50.70
7.04

Oxygen 2 16 22.54

1 71 100.00

In reference to this atomic estimate, which
is suggested by Leopold Gmelin,* Berzelius
observes, that from the feeble saturating power
of fibrine, its equivalent number is probably
very high, that is, that it includes a larger
number of simple atoms; but as we have at
present no accurate means of determining its
combining proportion or saturating power, its
atomic constitution cannot be satisfactorily
determined. Moreover, it appears that in the
above analyses the fat was not separated, nor is
any notice taken of the minute portion of sul-
phur, the presence of which has been above
adverted to.

When Berzelius first obtained fat from fibrine
by digesting it in alcohol and in ether, he con-
cluded that it arose from the decomposition of
a portion of the fibrine by those agents ; that it
was a product and not an educt ; but the sub-
sequent experiments of Chevreul leave no
doubt that the fat exists ready formed in the
blood. This fat is very soluble in alcohol, and
the solution is slightly acid ; when it is burned,
the ash, instead of being acid, like that of the
fatty matter of the brain, is alkaline, whence
it appears that it existed saponified, or partly
so, in the blood.

Another important variety of fibrine is that
which constitutes muscular fibre, but it is so
interwoven with the nerves and vessels and
cellular and adipose membrane, that its pro-
perties are probably always more or less modi-

* Handbuch der Theoretischen Chemie.

fied by foreign matters. The colour of muscles
appears to depend upon that of the blood in
their capillary vessels; and their moisture is
referable to water, which may be expelled by
drying them upon a water-bath, when they lose
upon an average 75 per cent. If muscular
fibre in thin slices is washed with water till
all soluble matters are removed, the residue,
when carefully dried, does not exceed 17 or 18
per cent, of the original weight.

To obtain the fibrine of a muscle, it must be
finely minced and washed in repeated portions
of water at 60° or 70°, till all colouring and
soluble substances are withdrawn, and till the
residue is colourless, insipid, and inodorous;
it is then strongly pressed between folds of
linen, which renders it semitransparent and
pulverulent. Berzelius observes that in this
state it becomes so strongly electro-positive
when triturated, that the particles repel each
other and adhere to the mortar, and that it stil
retains fat which is separable by alcohol or
ether. When long boiled in water, it shrinks,
hardens, and yields a portion of gelatine de-
rived from the insterstitial cellular membrane;
the fibrine itself is also modified by the con-
tinued action of boiling water, and loses its
solubility in acetic acid, which, when digested
with it in its previous state, forms a gelatinous
mass soluble in water, but slightly turbid from
the presence of fat and a portion of insoluble
membrane, derived apparently from the vessels
which pervaded the original muscle. It is
soluble in diluted caustic potassa, and precipi-
tated by excess of muriatic acid, the precipitate
being a compound of fibrine with excess of
muriatic acid, and which, when washed with
distilled water, becomes gelatinous and soluble,
being reduced to the state of a neutral muriate
of fibrine.*

When the fibrine of muscle is mixed with
its weight of sulphuric acid, it swells and dis-
solves, and, when gently heated, a little fat
rises to the surface and may be separated : if
the mass is then diluted with twice its weight
of water and boiled for nine hours, (occasion-
ally replacing the loss by evaporation,) am-
monia is formed, which combines with the
acid, and on saturating it with carbonate of
lime, filtering, and evaporating to dryness, a
yellow residue remains, consisting of three
distinct products : two of these are taken up
by digestion in boiling alcohol of the specific
gravity of .845, and are obtained upon evapo-
ration ; this residue, treated with alcohol of the
specific gravity of .830, communicates to it (1)
a portion of a peculiar extractive matter, and
the insoluble remainder (2) is white, soluble in
water and crystallisable, and has been called
by Braconnot kucine.\ It fuses at 212°, ex-

* It will be observed, by reference to the article
ALBUMEN, that that principle and Jibrine, if not
identical, are very closely allied, and appear rather
to differ in organization than in essential chemical
characters : accordingly the fibrine of the blood may
be considered as a modification of seralbumen, and
that of muscular fibre as little differing from the
fibrine of the blood.

t Ann. de Chim. et Phys. xiii. 119.

S 2

260

FIBRO-CARTILAGE.

haling the odour of roasted meat, and partly
sublimes : it is difficultly soluble in alcohol.
It dissolves in nitric acid, and yields on eva-
poration a white crystalline compound, the
nitro-leucic acid. The portion of the original
residue which is insoluble in alcohol (3) is
yellow, and its aqueous solution is precipi-
tated by infusion of galls, subacetate of lead,
nitrate of mercury, and persulphate of iron.
It appears therefore that the products of the
action of sulphuric acid upon the fibrine of
muscle, are, 1, an extractive matter soluble in
alcohol; 2. leucine; and 3. extractive, inso-
luble in alcohol but soluble in water.

(W. T. Erande.)

FIBRO-CARTILAGE, (Cartilago liga-
mentosa \.fibrosa ; Fr. Tissu fibrocartilagineux ;
Germ. Faser-Knorpel oder Band-Knorpel). —
As early as the time of Galen we find certain
organs distinguished by the appellation vtvgo-
Xovfyu&s o-fv^o-jLtot, and Fallopius uses a
similar term, namely, chondrosyndesmos, as
denoting a substance distinct from true carti-
lage. Haase* also, who wrote in 1747, speaks
of two structures different from true cartilage,
under the names of cartilagines ligamentosee
and cartilagines mixt<c. Bichat likewise recog-
nised a class of tissues distinct from pure
cartilage, and by him it would appear that the
namejibro-cartilage was first employed.

It is evident that no organ should be classed
under the head of fibro-cartiluge unless it con-
sist distinctly of fibrous tissue and cartilage
intermixed, and thus combine not only the
structure but the properties of both, the strength
and power of resistance of the one, and the elas-
ticity of the other ; nevertheless, we shall find,
in examining the various structures which are
admitted by anatomists to be fibro-cartilaginous,
that the fibrous tissue predominates in such a
manner as to justify Beclard in regarding fibro-
cartilage as a portion of the ligamentous struc-
ture, which might be designated cartilaginiform
ligamentous organs. The distinction was fully
admitted too by Mr. Hunter in reference to
the texture of the so-called inter-articular car-
tilages. Speaking of that of the temporo-
maxillary articulation, he says, " its texture is
ligamento-cartilaginous."f

The classification of fibro-cartilages adopted
by Meckel seems to me to be the best; he
arranges them under three classes: — 1. Those
whose two surfaces are free wholly or at least
in great part, and whose edges are united to
the synovial capsules, the moveable fibro-car-
tilages of articulation. 2. Those which are
free by one of their surfaces, and which adhere
to bone or tendon by the other : these are
the fibro-cartilages of tendinous sheaths, or
those which limit the articular cavities, and may
Tse called jibro-cartilages of circumference or
cylindrical fibro-cartilages. 3. Those whose two
surfaces are adherent in their entire extent to
the bones between which they are placed.

* De fabrica cartilaginum, Lipsise, 1747.
t Hunter on the Teeth.

Of these classes the first and third and some
of those which come under the second belong
to the articulations. Their forms and structure
have already been described in the article
ARTICULATION. I may here, however, notice
the statement of Weber* in regard to the discs
interposed between the vertebrae, which have
been generally regarded as fibro-cartilaginous.
This anatomist denies that they exhibit any
intermixture of cartilaginous substance, and
considers that this is rendered manifest by
stretching the intervertebral substance, by which
it becomes reduced to a fibrous expansion
( sehnighautige Masse) ; he consequently places
these intervertebral discs among the fibrous
tissues. There can be no doubt that the cir-
cumference of each disc is purely fibrous, and
that the concentric vertical lamellae of fibrous
tissue extend for some distance towards the
centre of the disc ; but I am at a loss to per-
ceive any resemblance to fibrous tissues in the
soft and elastic, and yielding substance which
forms the centre. It seems to me that this
texture can only be regarded as a modified
form of cartilage, differing in its want of
density from the ordinary cartilage, whether
permanent or temporary. The intervertebral
substance, however, to whatever texture it may
ultimately be decided to belong, does present
very striking differences from the other organs
which are placed among the fibro-cartilages.

It is in the fibro-cartilages of the second
class that we see most uniformly the inter-
mixture of the fibrous and cartilaginous texture,
although here, likewise, the fibrous tissue pre-
dominates over the cartilaginous.

The fibro-cartilages are remarkable for their
great flexibility, in virtue of which they are
enabled to resist fracture, and this property is
no doubt owing to the intermixture of fibrous
tissue; cartilaginous laminae, on the other hand,
are easily broken by bending, and many of
them exhibit a fibrous appearance on the surface
of the fracture, which, however, arises from
the irregular fracture and not from the existence
of fibres. Fibro-cartilages are of a dull white
colour and quite opaque; they have no perichon-
drium, but are either in immediate connexion
with bone, being inserted into it by their fibrous
bundles, or are covered by the synovial mem-
brane of the joint in which they are enclosed.
Their physical and vital properties are those
which belong to pure cartilage and to fibrous
tissue. Their force of cohesion is very great
and surpasses even that of bones. They are
more vascular than pure cartilage, but in the
natural state they admit very few vessels carry-
ing red blood. Bichat examined the fibro-
cartilages in an animal which died asphyxiated,
and found these organs not injected. The
remarkable manner in which fibro-cartilages
resist the influence of a compressing tumour, as
a pulsating aneurism, is well known; while by
such means the bodies of the vertebrae are
completely destroyed, the intervertebral discs
will remain quite uninjured.

* Einige Beobachtungen iiber das Structur der
Knorpel und Faser-Knorpel, in Meckel's Archiv
for 1827.

FIBRO-CARTILAGE.

261

Fibro-cartilages dry readily when exposed
loathe air and become of a deep yellow colour ;
they resist for a very long time, many months,
the influence of maceration, and by Long-con-
tinued boiling they become converted into a
gelatinous substance. Their chemical compo-
sition is said to be made up of albumen, phos-
phate of lime, chlorurets of sodium and of
potassium, sulphate of lime and other salts,
usually found in animal textures.

The microscopic characters of nbro-cartilage
do not seem to have been investigated with the
same care as those of many other textures. I
have examined by transmitted light very thin
slices of the fibro-cartilages in the knee and
temporo-maxillary joint, and the appearance
presented was uniformly that of a very compli-
cated cellular structure, composed of minute
meshes, very irregular in size and shape. In
examining the intervertebral substance I have
distinctly seen, towards the circumference of
the disc, those fine and uniform cylindrical
fibres with wave-like bendings described and
figured by Jordan ;* but towards the centre the
texture exhibited the cellular appearance with
larger meshes, similar to that seen in the fibro-
cartilages of the knee and joint of the lower
jaw.f

Of the structures placed by Bichat among
the fibro-cartilages, some have been considered
by Meckel, Beclard, Weber, and other anato-
mists to be pure cartilage, and as it seems to
me with much justice. These are the membra-
niform cartilages of the external ear, Eustachian
tube, nose, larynx, trachea, and eyelids. The
cartilaginous nature of most of these textures
is very apparent upon carefully dissecting off
the dense perichondrium which invests them,
and to which, doubtless, they owe their flexi-
bility, or more correctly, by which they are
prevented from being fractured under the
influence of a bending force. Careful micro-
scopic observation may assist materially in
affording marks indicative of pure cartilage ;
and as the observations of Purkinje, Miiller,
and Miescher approach in some degree to this
object, I have thought it not foreign to the
subject of this article to introduce here some
account of these researches. The results of
Purkinje's examinations of the minute structure
of bone as well as cartilage were published in
the year 1834 in an inaugural dissertation by
Deutsch.t Miiller and Miescher have further
investigated the subject and confirmed the
statements of Purkinje.§

In examining thin slices of cartilage under

* Uber das Gewebe der Tunica Dartos, &c.
Mullet's Archiv, 1834.

t Miescher states that in infants this part of the
intervertebral substance is composed of a pellucid
mucus, vrhich, under the microscope, sometimes
exhibits some of the cartilaginous corpuscles to be
noticed in a subsequent part of this article, but in
adults it is composed of adipose tissue!

$ De penitiori ossium structura. Diss. inaug.
Vratisl. 1834.

§ Vid. Miiller, Vergleichende Anatomic der
Myxinoiden, Berlin, 1835, and Miescher, de ossium
genes , structura, et vita. Diss. inaug. Berol.

Fig. 139.

the microscope by transmitted light, Purkinje
observed numerous little bodies irregularly dis-
persed through its texture, of a round or oval
form, and somewhat less transparent than the
intervening substance. The annexed figure,
taken from Miiller's work
already referred to, gives
a representation of these
bodies : they are deno-
minated by Purkinje
cartilaginous corpuscles
( Knorpel Korperchen}.
In some cases, as in tem-
porary cartilage, they ap-
peared to consist of mi-
nute granules ; they pre-
sented this appearance
likewise in the cartilagi-
nous part of the cranium
of a frog. In the costal
cartilages they were solid,
and in the cartilaginous
fishes, as in the lamprey,
their contents were of a
soft or fluid consistence. According to Purkinje,
these corpuscles are found in the temporary
cartilages, in permanent cartilage, in cartilage
which becomes ossified in old age, as that of
the ribs and larynx, in the cartilages of the
nose and septum narium.

According to Miescher there are two kinds
of permanent cartilage, differing from each
other as well by external characters as by in-
ternal structure ; one of these scarcely differs
at all from the temporary cartilage, the other
is very dissimilar in structure. The first class
is at once distinguished by its azure whiteness
and by its pellucid brightness, not unlike that
of mother-of-pearl, from the second, which is
yellowish in colour, not pellucid, and spongy
in texture. To the former class belong all
articular cartilages, those of the ribs,* that of
the ensiform cartilage of the sternum, the thy-
roid, cricoid, and arytenoid cartilages, and
those of the septum narium and alae nasi.
All the cartilages of this class are characterized
by containing the microscopic corpuscles above
described, variously arranged in each form of
cartilage, in some placed in clusters, in others
closely aggregated together in one part and
separated in another. It is interesting to ob-
serve that the temporary cartilage universally
contains these corpuscles, and as all the carti-
lages we have described are more or less prone
to ossification in advanced age, we are led to
the inference, that these corpuscles thus de-
posited are characteristic of cartilage which
admits of becoming ossified.f

* Sic Miescher.

t The cartilages most liable to ossify by the pro-
gress of age in man, are those which most fre-
quently exhibit, after a certain period, a per-
manently ossified condition in some of the inferior
classes of animals. Thus, in birds, and among
mammals, inmonotremata,cheiroptera,and cetacea,
the cartilages of the ribs show a very early dis-
position to ossify. In birds the laryngeal cartilages
are very apt to ossify, and in swine and oxen par-
tial ossifications of the same cartilages are not

262

FIBRO-CARTILAGE.

To the second class of cartilages belong
those of the external ear, of the epiglottis, and
the capitula of Santorini, connected with the
apices of the arytenoid cartilages, which in the
ruminants, the hog tribe, and others, are of con-
siderable size. Besides the characters already
mentioned which distinguish this class of car-
tilage from the former, the microscope dis-
closes some further differences. " Placed
under the microscope," says Miescher, " the
cartilages of this class present a very delicate
network, opaque, composed of small round
meshes which are filled by a uniform, pellucid
substance, and each generally contains a single
corpuscle somewhat roundish or oblong/' The
cartilages that belong to this class are con-
trasted with those of the former, as being never
transformed into bone.

I may add, that in my own examinations of
pure cartilage, from the skeletons of cartila-

r'nous fishes, and from the human subject,
have found the foregoing descriptions correct.
The cartilaginous corpuscles may be always
seen under the compound microscope, with an
object glass of a quarter of an inch or an eighth
of an inch focus.

In man and the mammalia, the following
structures may be enumerated as belonging to
the class of fibro-cartilages: 1. The so-called
inter-articular cartilages in the knee, sterno-
clavicular, and temporo-maxillary joints; that
in the wrist-joint seems to me to be purely
cartilaginous. 2. The fibro-cartilages of cir-
cumference, as in the hip and shoulder-joints.
3. The fibro-cartilages of tendons, which ulti-
timately form sesamoid bones, and those of
tendinous sheaths. 4. According to Miescher,
the tarsal cartilages. 5. The inter-osseous
laminae, as those between the pubes, pieces of
the sacrum and coccyx, and, in a modified form,
the intervertebral substance.

In the inferior vertebrata and in the inver-
tebrata fibro-cartilage gradually disappears :
in the former, the intervertebral substance
seems to be the only remnant of it, excepting
perhaps the sclerotic coat of the eye in some
fishes. In the invertebrata, Blainville considers
the three tubercular teeth of the leech as being
fibro-cartil agin ous .

Morbid conditions of ^fibro-cartilage. — As
fibro-cartilage in its physical and vital pro-
perties so nearly approaches pure cartilage, it is
reasonable to expect a great similarity in the
phenomena of disease as they are manifested
in the two tissues. Fibro-cartilage appears to
be susceptible of reparation in the same man-
ner as pure cartilage. (See CARTILAGE.) A
substance bearing some resemblance to fibro-
cartilage sometimes forms the connecting me-
dium between the fractured portions of a bone,
where bony union cannot be obtained.

The phenomena of inflammation and ulce-
ration in fibro-cartilages are very similar to

unfrequently found. Ossification of the nasal
cartilages is extremely rare, but in the hog tribe
two bones extend from the intermaxillary bone into
the cartilage of the proboscis. — Vide Miescher,
loc. cit. p. 27.

those in pure cartilage : in the joints these
morbid changes are generally complicated with
similar diseased conditions of the other tex-
tures, either cartilages or bones, whence they
are propagated to the fibro-cartilages. It is
well known that a condition of the interverte-
bral discs, which is commonly spoken of under
the name of ulceration, is frequently coin-
cident with caries of the vertebrae, having in
some instances preceded the vertebral disease,
and in others followed it. To Sir Benjamin
Brodie we are indebted for the observation that
the diseased state of the intervertebral substance
has sometimes the precedence of that of the
bones; in one case, related by him, where
ulceration of the articular cartilages had begun
in several other parts, those between the bodies
of some of the dorsal vertebrae were found to
have been very much altered from their natural
structure. He adds, " I had an opportunity
of noticing a similar morbid condition of two
of the intervertebral cartilages in a patient who,
some time after having received a blow on the
loins, was affected with such symptoms as in-
duced Mr. Keate to consider this case as one
of incipient caries of the spine, and to treat it,
accordingly, with caustic issues; and who
under these circumstances died of another
complaint. Opportunities of examining the
morbid appearances in this very early stage of
disease in the spine are of very rare occur-
rence, but they are sufficiently frequent when
the disease has made a greater progress ; and
in such cases I have, in some instances, found
the intervertebral cartilages in a state of ulce-
ration while the bones were either in a perfectly
healthy state, or merely affected with chronic
inflammation, without having lost their natural
texture and hardness.'7* Otto mentions that
he has several times satisfied himself that the
destruction of the spine may originally spring
from the intervertebral substance ; but he has
never found suppuration, unless when at the
same time the bones and neighbouring cellular
tissue were inflamed.f The anatomical cha-
racters of this condition to which we have
been alluding consist in an erosion and soften-
ing of the fibro-cartilage, frequently attended
with the effusion on the surface of a dirty
puriform and often fetid fluid.

Fibro-cartilage is not prone to become ossi-
fied; in very old subjects the superficial portion
of the intervertebral substances is often ossi-
fied, but this is an extension of ossification
from the bone or from the anterior common
ligament : it is very rare to find any of the
inter-articular fibro-cartilages ossified. The
ossification of the interpubic fibro-cartilage in
advanced age seems to be of a similar nature
to that of the intervertebral substances.

Masses of a substance very similar to fibro-
cartilage are sometimes met with accidentally
developed ; we find them in or connected with
the uterus, in tumours, and in serous or sy-
novial membranes.

( R. B. Todd.)

* Brodie on the Joints, edit. 2d, p. 231.
t Pathol. Anat. by South.

FIBROUS TISSUE.

263

FIBROUS TISSUE,* telafbrosa, vel ten-
dinea ; Germ, das sehnige Gewebe.

The parts comprised in the fibrous system
may with propriety be referred to twd separate
and distinct classes.

I. WHITE FIBROUS ORGANS. — Under this
head the following structures, distinguished by
their whitish colour, their fibrous organization,
and their great power of resistance, are in-
cluded : — «, the periosteum and perichondrium ;
6, fasciae or muscular aponeuroses ; c, sheaths of
the tendons ; d, fibrous coverings of certain
organs ; e, ligaments; J\ tendons.

II. YELLOW ELASTIC FIBROUS ORGANS. —
There are certain organs, ex. gr. the yellow
ligaments (ligamenta sub/lava) of the spine,
which resemble those of the former class by
their fibrous structure, but which present so
many important peculiarities in their texture
and properties, that it is necessary to consider
them apart from the preceding. All these
organs resemble each other by possessing more
or less a yellow colour, and a remarkable de-
gree of elasticity.

I. WHITE FIBROUS ORGANS. — Organiza-
tion. This consists of a union of white
or grayish fibres more or less distinct accord-
ing to the part in which they are examined ;
thus they are very apparent in most of the
ligaments, in the fasciae, in the periosteum, and
in many tendons, as in those of the obliquus
abdominis externus, pectoralis major, &c. In
other structures, on the contrary, as in the
greater number of tendons, the fibres are so
small and so closely united that they cannot be
perceived but with difficulty, although they be-
come more evident on maceration. In most
parts of the body they observe a parallel direc-
tion, whilst in other places they pass in an irre-
gular manner, so as to cross and interlace with
each other, occasionally constituting, as in the
instance of the dura mater and of the tendinous
centre of the diaphragm, a very intricate net-
work of fibres.

The result of a careful examination proves
that the remarkably firm and resisting threads
which constitute the basis of the various fibrous
organs, are composed of condensed cellular
tissue. In certain regions we may perceive
the gradual transformation of the cellular tissue
into a fibrous organ, as in the formation of the
superficial fascia of the abdomen; whilst by
prolonged maceration the most dense tendon
or ligament may be reduced into a pulpy cellu-
lar substance : this opinion is corroborated by
Isenflamm, who conceives that this tissue is
formed by cellular fibres impregnated with
gluten and albumen ; and also by Beclard, who
regards it as being composed of cellular texture
very much condensed. We may therefore
conclude that the ideas of Professor Chaussier,

* The expression fibrous tissue is by no means
well chosen, as it is equally applicable to other and
dissimilar organs, such as muscles, nerves, &c. all
of which are eminently distinguished by a fibrous
structure. It is, however, preferable to retain a
received though inaccurate term, than to add to
that multitude of names which already so much
encumbers the science of anatomy.

as to the existence of an elementary organic
solid, called by him the albugineous fibre, and
which is supposed to form the basis of all the
ligamentous and tendinous parts of the body,
are erroneous.

The individual fibres are surrounded by pro-
cesses of a more lax membrane, which pene-
trates between them, and which is rendered
particularly apparent by maceration and in cer-
tain diseases. The differences that are observed
in contrasting the various fibrous organs with
each other, a ligament for example with a ten-
don, seem principally to result from the larger
or smaller proportion of the interfibrous cellu-
lar substance and on the degree of its conden-
sation. This combination of the common cel-
lular tissue with the ligamentous fibres allows
the fibrous organs to yield in a very slight de-
gree when extended by the elasticity which is
thus bestowed, and also slightly to contract on
themselves on the removal of the extending
force.

Bloodvessels. — The proper fibrous tissue re-
ceives but a small quantity of blood, the arteries
being minute in size, and principally carrying
a colourless fluid. The great vascularity of the
dura mater and periosteum is no exception
to this remark, because the vessels of these
membranes are not proper to them, but to the
veins they cover.

Absorbents. — The ravages of disease in the
neighbourhood of joints, involving the liga-
ments in ulceration ; the sloughing of tendons,
the destruction of the periosteum by the pres-
sure of aneurism, of the tunica albuginea in
scrofulous or malignant fungus of the testis,
are abundant proofs of the existence of absor-
bent vessels.

Nerves. — According to Monro, nervous fila-
ments may be traced to some of the fibrous
organs ; and other anatomists, Cruveilhier for
instance, speak of nerves being furnished to
the joints ; in general, however, none are to be
seen ; but as sensibility becomes developed in
disease, we must presume that communications
do exist with the encephalon.

Chemical properties. — The principal sub-
stances that have been detected in the fibrous
as in the cellular tissue consist of coagulated
albumen and gelatine; a small quantity of
mucus and saline matter has also been disco-
vered. The effects of desiccation are well
known, tendons and ligaments becoming hard,
transparent, yellowish, and fragile. This tissue
resists maceration for a long time, but at length
it is rendered soft and flocculent, so that the
fibres can be separated and unravelled ; ulti-
mately it is converted into a pulpy and fila-
mentous cellular mass.

Properties. — The offices which these organs
are designed to fulfil in the economy being,
with the exception of the periosteum and its
analogous membrane the dura mater, of a me-
chanical character, the properties by which
they are distinguished are almost entirely of a
physical nature. They offer great resistance to
rupture, and thus the ligaments are capable of
opposing the shocks to which, in the violent
movements of the joints, they are so frequently

264

FIBROUS TISSUE.

exposed; whilst the same cohesive property
enables the tendons, under all ordinary circum-
stances, to bear the immense force of muscular
contraction.

Having considered the general characters of
these organs, I shall proceed to describe the
most essential properties of each individual
class.

1. Of the periosteum. — This may be regard-
ed as the most important of the fibrous tissues;
indeed so universal are its connexions, that if
any common centre of this system were sought
for, we should certainly coincide with Bichat
in considering this to be the periosteum. Dis-
carding the erroneous ideas of the ancients and
Arabian physicians, who imagined that the
membranes of the body were all continued
from those of the head, we shall find that, with
the exception of the perichondrium of the larynx
and the fibrous tunics of some glandular bodies,
all the fibrous organs are in connexion with the
periosteum.

The inner surface of the periosteum firmly
adheres to the several bones by a multitude of
delicate processes passing into the openings
observed on their external surface. These pro-
cesses convey into the bones an amazing num-
ber of fine arteries and veins, called therefore
periosteal, and which may be regarded as the
principal, or as some anatomists contend, the
only proper vessels of the osseous tissue.

The outer surface is rough, and is united by
the cellular tissue to the surrounding muscles,
tendons, ligaments, and fasciae ; in the nostrils,
sinuses, and tympanum, the periosteum is,
however, joined to the mucous membranes,
and in the skull the surface unattached to the
bones is lined by the arachnoid.

The periosteum constitutes the nutrient
membrane of the bones, and thus bears an im-
portant part in the process of ossification and
in the reparation of fractured and diseased
bones ; it also serves as a medium for the
attachment of the ligaments, tendons, and
fasciae to the skeleton.

2. Fascia. — The fibrous fasciae or aponeu-
roses not only invest the surface of the limbs,
but also furnish a number of processes, which,
penetrating deeply among the several muscles,
form sheaths to those organs, by which they as
well as the bloodvessels and nerves are main-
tained in their proper situation. It is evident
that these partitions must exert a great influence
on the growth of various kinds of tumours, on
effusion of blood, on the extravasation of urine,
and on the formation of matter; so that their
relations form an important branch of surgical
anatomy.

In order to give to these muscular envelopes
the necessary degree of tension, they are either
provided with special muscles, as in the case
of the tensor vaginae femoris and the palmaris
longus, or they receive processes from the
neighbouring tendons, as from the biceps cubiti,
semi-tendinosus, and so forth.

The aponeuroses thus braced afford a firm
support to the parts they cover, and in this
manner they increase the powers of the muscu-
lar system ; whilst by their resistance they

efficiently protect the vessels and nerves from
external violence, and at the same time proba-
bly assist in the circulation of the blood and
lymph, and so prevent varicose enlargement of
the deep-seated veins and oedema of the extre-
mities. See FASCIA.

3. Tendinous sheaths. — These are in their
office analogous with the last, excepting that,
instead of fixing the muscles, they secure the
tendons during muscular action. The thecal
ligaments of the hand and foot, the annular
ligaments of the wrist and ankle, and the fascial
sheaths around the knee are of this character.
They are distinguished by their great strength,
and as they are internally lined by synovial
membrane, they facilitate the play of the ten-
dons ; and in many instances, as in the trochlea
of the os frontis and the sulci of the carpal extre-
mity of the radius, they also modify the action
of the muscles whose tendons they transmit.

4. Fibrous coverings. — Certain organs are
provided, for the purpose of protection, with
dense ligamentous coverings ; of this order are
the dura mater, the sclerotic coat of the eye,
the loose portion of the pericardium, the proper
covering of the kidney, of the salivary glands,
mamma, spleen, thyroid gland, thymus, lym-
phatic glands, of the prostate, testicle and
ovary ; probably the exterior investment of the
nervous ganglia is of the same character. Some
of these envelopes, as the dura mater, pericar-
dium, and tunica albuginea testis, are lined on
one surface by a serous membrane, and thus
constitute fibro-serous membranes, or as they
are called by Beclard, compound fibrous mem-
branes.

5. Ligaments. — These bodies possess in an
eminent degree those properties by which the
whole fibrous system is distinguished ; and
consequently the term ligamentous is often em-
ployed to designate the whole of the fibrous
organs.

The ligaments fulfil a very important office
in the animal economy by binding together the
various bones of the skeleton, an object which
they are enabled to effect in consequence of
their fibres being very firmly attached, and as
it were consolidated with the osseous system
through the medium of the periosteum. It is
stated by Portal, that after the bones have been
softened by the influence of an acid, the liga-
ments are observed to send processes into their
substance, which cause the ligaments to adhere
so firmly that, although by very great force
they may be torn, yet they cannot be separated
from the bones.

Although these organs are dissimilar in
shape, yet there are three forms among them
which predominate: 1. the capsular, 2. the
funicular, 3. what, for want of a better ex-
pression, may be called laminated. The true
fibrous capsules which consist of cylindrical
bags lined internally by synovial membrane,
are confined to the shoulder and hip-joints,
although imperfect capsules exist in many
other articulations. The funicular and la-
minated ligaments are much more universally
diffused, assisting in fact in the formation of
every joint in the skeleton.

FIBROUS TISSUE.

265

6. Tendons. — These organs, which serve to
connect the muscles to the osseous system,
are composed of fibres so closely disposed
that some anatomists, but erroneously, doubt
their identity with the other fibrous organs.
This compactness is owing to the extreme con-
densation of the intervening cellular tissue,
which is also the cause of these bodies re-
sisting for a longer period than the ligamen-
tous or fascial structures, the influence of ma-
ceration.

Every tendon is united by one of its ex-
tremities to the fibres of the muscle to which
it belongs, and by the other it is connected
with the bone or other part on which the
muscle is destined to act. The exact mode
of connexion between the tendinous and mus-
cular tissues is difficult to determine. Ocular
and microscopical inspection seem to prove
that the tendinous fibres result from the con-
tinuation and condensation of those cellular
sheaths, which inclose and in part form the
muscular fibrils. It has, however, been stated
that there is an intermediate substance between
the muscle and the tendon, different from
both of them, and serving to connect them
together. The details relative to the mecha-
nical disposition of these organs belong to the
consideration of the muscular system. — See
MUSCLE.

II. YELLOW ELASTIC FIBROUS ORGANS. —
( Tela elasticu. ) It was justly observed by
Bichat that the ligaments placed between the
arches of the vertebrae differ in their nature
from the other ligaments of the body; and
modern anatomists, admitting this distinction,
have enumerated the following structures as a
separate class of the fibrous organs : the yellow
ligaments of the spine; the external and espe-
cially the middle or proper membrane of the
arteries, the fibrous covering of the excretory
ducts ; the ligamentous tissue joining the carti-
lages of the air-passages ; the fibrous envelope
of the cavernous bodies of the penis and clitoris,
and of the vesiculae seminales.

Although the highest authorities consider
that the middle tunic of the arteries is com-
posed of this tissue, yet the correctness of this
opinion is very doubtful. It is true that, as
far as colour is concerned, the similarity is
well founded ; but the arterial fibrous coat is
endowed with a power of contraction, evi-
dently distinct from mere elastic contraction,
which is totally wanting in the true yellow
fibrous tissue.

In addition to the parts above named, it is
necessary to add that in certain organs where
great elasticity is requisite there is a peculiar
yellow cellular substance, which, although it
does not present the dense and fibrous cha-
racter, appears to belong essentially to the
organs under consideration. This texture is
particularly distinct in the mucous folds
which constitute the superior boundary of the
glottis, a part that is remarkable for its extra-
ordinary elasticity.*

* It is stated by Sir E. Home (Lect. on Comp.
Anat. vol. ii. p. 49,) that this tissue enters into the

It occasionally happens, as in the forma-
tion of the intervertebral substance, that the
yellow fibrous tissue and the common liga-
mentous are combined. A more striking
instance of this combination is seen in the
construction of the connecting ligament which
forms the hinge in bivalve shells, in which one
part, the external, is composed of ligamentous
matter, whilst another, the internal, consists
of a highly elastic fibrous tissue.

Organization and properties. — If the yellow
ligament of the spine or the ligamentum nu-
chae in ruminants be examined, it will be seen
that each is smooth on its surface, and is made
up of a great number of longitudinal and
highly elastic fibres, which, in the latter in-
stance, are readily separated and unravelled
by the finger. This texture is, I believe, sui
generis, and is altogether distinct from the
common ligamentous structures. In a recent
publication,* M. Laurent conceives that this
tissue is intermediate in its characters to the
tissus sclireux (under which term he proposes
to class the white fibrous organs, the cartilages
and bones,) and the muscular tissue ; he there-
fore calls it tissu sclero-sarceux. Although it
is very doubtful if the elastic fibrous structures
have any thing in their organization similar to
the muscular fibre, yet it is certain that in
function they are intermediate between the
common ligaments and the muscles, a fact
which is kept in view in theHunterian Museum,
in which the elastic ligaments are placed next to
the muscles.

The resistance and elasticity of these organs
enable them firmly to connect together the
parts to which they are attached, and at the
same time allow them to yield to double their
length on the application of an extending
force. In this manner they economise mus-
cular action, by substituting for that force the
power of elasticity.

This employment of an elastic rather than
a muscular power is evinced in the yellow
ligaments of the spine, which pull the vertebrae
towards each other, and thus assist the muscles
in maintaining the upright posture. The same
thing is also seen in many of the lower ani-
mals ; as in the support of the head by the
ligamentum nuchse — the retraction of the claws
in the feline carnivora by an elastic ligament —
and the support of the abdominal organs in
many large quadrupeds by the elastic super-
ficial fascia. But the most interesting ex-
ample of this economy of muscular action
is displayed in the bivalve shell of the oyster
and other acephalous mollusca, in which in-
stance not only is the shell kept open by the
elastic ligament of the hinge for the purpose
of admitting the nutriment of the animal; but

formation of muscle ; but this is probably erro-
neous, as the elasticity of muscles depends on the
large proportion of elastic cellular membrane which
they contain. Lobstein has also published some
observations in the Jour. Univer. des Sc. Med. on
the tissue of the uterus, which he regards as ana-
logous to the so-called yellow tissue of the middle
arterial coat.

* Annales Franchises et Etrangcres d'.Anat. et de
Physiol. Jan. 1837. P. 59.

266

FIBROUS TISSUE.

as the valves are designed by nature to be
separated only to a limited extent, an elastic
ligamentous structure is placed between them
towards their centre, and in this manner all
undue separation is prevented without any
demand being made on the force of the ad-
ductor muscle.*

MORBID ANATOMY. I. Inflammation. —
The low degree of organization possessed by
this tissue modifies the inflammatory process,
which is usually chronic in its nature, and
often extremely insidious in its progress ; occa-
sionally, however, as in sprains, acute rheu-
matism, &c., the fibrous organs are the seat
of very active disease. Owing to their great
density, but little swelling takes place unless
there be chronic and prolonged inflammation ;
in which case, as is particularly observed in
disease of the joints, a quantity of jelly-like
fluid is poured into the interstitial cellular
tissue, the proper fibres become massed toge-
ther and with the surrounding parts, till in the
advanced stage all traces of the original for-
mation being lost in the diseased mass, it be-
comes reduced to the pulpy consistence of
diseased cellular membrane, of which the
healthy structure is a modification.

This deposit and thickening are the most
common products of inflammation in liga-
mentous parts ; but it occasionally happens
that a true abscess is formed, as when pus is
thrown out between the dura mater and cra-
nium. I have known one case connected with
disease of the bone, in which matter was de-
posited in the substance of the dura mater,
and in which the operation of trephining was
ultimately required for the relief of the patient.

Ulceration is a frequent result of scrophu-
lous disease of the joints, causing great ravages
in the ligaments and neighbouring parts.

Mortification of ligament is not a common
occurrence, whilst in the acute inflammation
of tendon, especially in neglected thecal ab-
scess, and of fascia in consequence of large
abscess under it, sloughing is not unfrequently
witnessed.

There are of course certain modifications in
the effects of inflammation according to the
part attacked. Thus, in ligament, there is a
great tendency to ulceration ; in tendon to
mortification ; in the periosteum to great in-
duration ; and, as we see in the formation of a
node and of callus, to a transformation into
cartilage and even bone. When fascia is the
seat of disease, the consolidation arising from
effusion often gives rise to a retraction of the
affected part; a result which has been observed,
for example, in inflammation of the aponeu-

* Leach, Bullet, des Sciences, 1818. P. 14.
[Mr. Hunter fully recognised the value of this
elastic tissue, and in his Museum he set apart a
series for its illustration under two classes — 1st, as
an antagonist to muscle, and 2d, in aid of mus-
cular action. In the former class he places such
examples as that of the oyster alluded to in the
text, in the latter the ligamenta nuchae and the
elastic fibrous expansion on the abdomen of the
elephant and other larger quadrupeds. See the
Descriptive and Illustrated Catalogue of the Hun-
terian Museum, vol. i. — ED.]

rosis of the fore-arm, and in that affection of
the palmar fascia called by Boyer and other
writers crispatura tendinum*

II. Cartilaginous transformation and ossi-
fication.— Many parts of the fibrous system

not unfrequently become cartilaginous or even
osseous. The cartilaginous transformation is
often observed in the ligaments of diseased
and anchylosed joints; in the periosteum after
fractures and in the formation of nodes; in
tendons, especially those which are exposed to
great friction in the fibrous covering of the
spleen. I have had opportunities of seeing
many specimens of cartilaginous deposit taking
place between the periosteum and the bone,
and evidently arising from the former. The
valuable collection of my friend Mr. Liston
contains a very fine specimen of a large carti-
laginous tumour proceeding from the peri-
osteum.

Ossification, although extremely common,
occurs much more frequently in some than in
other classes of these organs : thus it is often
met with in the dura mater, in which structure,
as far as I have observed, the bony excres-
cence always proceeds from the inner layer or
that towards the arachnoid, and consequently
presses against the brain. In one very re-
markable specimen in my possession, nearly
the whole of the falx, and a large extent of the
membrane attached to the vault of the cranium,
are completely ossified. In an instance, ob-
served I believe by Dr. Barlow (Southwark),
the heart was completely encased in bone,
owing to the entire ossification of the peri-
cardium. The cicatrix of a wounded tendon
is often osseous.

III. Fungus. — The dura mater, the peri-
osteum, the fascia, &c., are subject to excres-
cences having a fungoid appearance, which
vary in their nature, often consisting of a
chronic, indolent growth, whilst at other times
they are evidently scrophulous, and occasion-
ally they are malignant.

In the progress of those cases where the
disease is situated near the bones, these organs
are implicated, and some doubt has conse-
quently arisen concerning the first seat of the
disease ; it is, however, proved by examination
that in the fungus of the dura mater and other
fibrous parts, the bones are only secondarily
affected. A good illustration of this fact is
afforded by a preparation consisting of an
extensive fungus arising from the periosteum
covering the tibia, in which it is evident, al-

* Boyer, Traite des Malad. Chir. torn. v. p. 55.
This peculiar affection was so'me years since pointed
out by Sir A. Cooper, and has since been more fully
described by Baron Dupuytren, (Le9on« Orales de
Chir. Clin. torn. i. p. 2). The tension and contrac-
tion of the palmar fascia, which are usually caused
by continued pressure, give rise to aretraction of one
or more of the fingers, and may be removed by
transversely and freely dividing the aponeurosis
opposite to the metacarpo-phalangean joint. I
have known one case of similar induration of the
fibrous sheath of the corpus cavernosum penis ;
and I have learnt from Sir A. Cooper that he has
seen several such cases, occurring in persons who
had freely indulged in sexual intercourse. Boyer
has made a similar observation.

FIBULAR ARTERY.

267

though the subjacent bone has been partly
absorbed, that the fungoid disease entirely
originated from the periosteum.*

Malignant fungus occasionally arises from
the periosteum. I have seen one case of this
disease connectea with the tibia, in which
amputation was performed, but with an un-
favourable result, the patient sinking rapidly
from mortification. In medullary sarcoma
that membrane is often involved.

Osteo - sarcoma, according to Howship,
Craigie, and Meckel, occasionally has its ori-
gin in the periosteum.

(R. D. Grainger.)

FIBULAR ARTERY, (arteria peronxa ;
Fr. arttre peroniere ; Germ, die Wadenbein-
arterie). — This artery is commonly described
as a branch of the posterior tibial, or it may
be said to be one of the branches resulting
from the bifurcation of a short trunk which has
its origin immediately from the popliteal, and
which has been described under the name of
the tibio-peroneal artery, the other branch of the
bifurcation being what is ordinarily considered
as the continued posterior tibial trunk.

The origin of the fibular artery is situated
about an inch below the inferior margin of the
popliteus muscle, thence the artery extends
downwards and with a very gradual inclination
outwards, and terminates in the region of the
external ankle, just above the os calcis and
behind the fibula. It is a vessel of smaller
size than the posterior tibial, and about equal to
the anterior tibial, and it is interesting to ob-
serve that the varieties in its calibre are in the
inverse ratio of the calibre of the anterior and
posterior tibial, but more especially of the
former.

To expose the fibular artery in dissection the
gastrocnemius and soleus muscles must be
raised, and the deep fascia of the leg dissected
away. The artery is then seen resting at first
for a very short distance upon the tibialis posti-
cus muscle, and from it getting upon the pos-
terior surface of the fibula near its tibial edge,
where the vessel is imbedded in the flexor pol-
licis proprius and encased between that muscle
and the bone. Inferiorly it passes between the
flexor pollicis proprius and tibialis posticus,
and is applied to the posterior surface of the
interosseous ligament.

The fibular artery is sometimes altogether
absent, and then its place is supplied by rami-
fications of the posterior tibial. Sometimes
the fibular artery takes its rise higher up than the
point we have indicated ; but more frequently
it has a lower origin, in which case it presents
a calibre smaller than that which may be con-
sidered as usual ; the vessel, indeed, is found to
be smaller the lower down its origin is. It is
in these cases that the anterior tibial especially
and the posterior tibial occur of a larger size than

* The result of dissection induces me to suppose
that in many old and intractable ulcers, the fun-
goid excrescences seen on the surface aiise either
from the fascia of the leg or from the periosteum,
according as they are placed on the outc r or inner
part of the limb.

natural, as it were to compensate for the de-
ficiency of the fibular.

Branches. — The first branches the fibular
artery gives off are small muscular ones on
either side to the soleus, tibialis posticus, flexor
pollicis proprius, to which in its whole course
it gives a liberal supply; also to the fibula and
the peronaei muscles. From its inner side,
according to Cruveilhier, it gives an anasto-
motic branch to the posterior tibial, which
passes transversely or obliquely from one artery
to the other. This branch sometimes attains a
considerable size, and in such cases after its
communication with the posterior tibial, that
artery also becomes considerably enlarged.

The fibular artery divides into its two termi-
nal arteries in the inferior third of the leg;
these are the anterior and posterior peronaeal
arteries.

Anterior peroneal artery, (arteria peronaa
anterior and perforans peronaa.) This branch
gains the anterior surface of the leg by piercing
the interosseous ligament, where it is covered
by the peronaeus tertius muscle. The situation
at which this perforation takes place is stated
by Harrison to be about two inches above the
external ankle; it then inclines downwards
upon the outer side of the tibia, anastomoses
by a transverse branch with the anti-tibial, com-
municates with the external malleolar artery
from the anterior tibial, giving off numerous
branches both before and after the anastomosis,
which pass down to the tarsus and communi-
cate with the tarsal arteries. This artery is
generally smaller than the posterior, some-
times so small that the ordinary injection fails
to penetrate it. If there be any anomaly in the
size of the anterior tibial artery, this branch is
generally large in proportion as that artery is
small, and in such a case it might exceed the
posterior peroneal in calibre. The arteries of
the dorsum of the foot spring from the anterior
peroneal when the anterior tibial exhibits this
deficiency.

Posterior peroneal artery, (A. peronaa pos-
terior; calcanienne externe, Cruveilhier). This
branch continues the course of the fibular artery
behind the external malleolus to the outer side
of the os calcis; it runs parallel to the outer edge
of the tendo Achillis, being immediately covered
by the continuation of the fascia of the leg.
A transverse branch from the inner side of this
artery establishes its communication with the
posterior tibial, and inferiorly it distributes its
terminal branches to the muscles and other
parts on the outside of the os calcis to anasto-
mose with the external tarsal and plantar
arteries ; some small vessels proceed round the
tendo Achillis to effect a further communication
with the posterior tibial.

This may be considered as the terminal
branch of the fibular artery ; it is absent only
when the fibular artery passes entirely forwards,
or when it directly opens into the posterior
tibial without having any further communica-
tion with the arteries of the ankle.

The fibular artery is evidently a valuable
anastomotic trunk to both the tibial arteries, a
deficiency in either of which it is prepared to

268

FIFTH PAIR OF NERVES.

supply. Deriving its origin from the same
source, and anastomosing freely with both in
all parts of their respective courses, it is pre-
pared to take the place of either, one might say,
at a moment's warning, and the freedom of
this communication affords a sufficient indica-
tion to surgeons how ineffectual in cases of
wounds a single ligature would be ; in short,
here as in other places where arterial communi-
cations are so free, the rule of practice is so
clearly pointed out by the anatomy as almost
to render it superfluous to appeal to experience.
The relations of this artery to operations being
very similar to those of the posterior tibial, we
refer on this head to the article TIBIAL AR-

TERIES.

(R. B. Todd.)

FIFTH PAIR OF NERVES.— This title
is derived from the relation which the nerve
bears numerically to the other encephalic pairs;
it is the fifth nerve met with on the base of the
brain counting from before backwards. The
fifth is also called the trigeminal (Winslow)
and the trifacial (Chaussier) nerve. It is the
nerve upon which the general and tactile sensi-
bility of the face and its cavities, as well as the
voluntary power of certain muscles of these
parts, depends.

The following account of this nerve is meant
to apply especially to the human subject; but
as a knowledge of its structure and distribution
in other animals must contribute very much to
enlighten us in regard to its true character and
properties in man, occasion has been taken to
mention those particulars by which it is dis-
tinguished throughout the animal series.

The fifth nerve is connected at its one ex-
tremity with the medulla oblongata, whilst
its other end is distributed to the eye and its
appendages, to the nostrils, to the palate, the
mouth and tongue, to the salivary glands, to
the ear, to the integuments and muscles of
the face, forehead, and temple, and to the
muscles which move the lower jaw in mas-
tication, the temporal, pterygoid, and mas-
seter muscles. The general distribution of the
nerve throughout the animal series corres-
ponds to that in man ; but, in certain animals
and classes, varieties are presented, which
claim our attention equally, whether as matters
of curiosity or of physiological interest. In
some individuals of the class Mammalia, the
eyes possess a very inferior degree of develop-
ment; a distinct optic nerve either does not
exist or its existence is a matter of doubt,
and its place is supplied, in part or alto-
gether, by a branch of the second division
of the fifth nerve: thus, in the Mole, accord-
ing to M. Serres,* the optic is altogether
absent, and its place is supplied by a branch
of the fifth ; but, according to Treviranus,f
that animal is provided with an optic nerve,
as large as a human hair, and according to
CarusJ it joins an optic branch from the fifth,
and the two concur to form the retina. In

* Anatomie Comparee du Cerveau, &c.
t Journal Complemeritaire.
J Journal Compl.

other animals of the same class the optic seems
decidedly absent, and its place is supplied al-
together by the fifth. Among Reptiles also in-
stances occur, in which the optic nerve is
wanting. According to botji Treviranus* and
Serres, f the fifth nerve takes the place of
the optic in the Proteus Anguinus. A va-
riety in distribution, still more remarkable,
is presented in the disposition of the fifth
nerve in Fishes. Among the Rays the audi-
tory appears to be, not a distinct nerve, but
a branch of the fifth : J the special organs,
with which they are provided, likewise, in
many instances, derive their nerves from the
fifth pair; thus, in some the electrical § organs
are supplied by that nerve, and also the albu-
mino-gelatinous organs: lastly, in many the
nerve is distributed || in a manner and to an
extent for which there is no analogy among
other animals, the fins being throughout fur-
nished with branches from the fifth. Hence
in Fish, in which the distribution of the
nerve is so much more extended than in
other animals, both the size of it is propor-
tionally greater, and it consists of a greaterlf
number of divisions ; these, which in the three
other classes of vertebrate animals are only
three, amounting with them to from three to
six. See sketch of nerves in the Ray and Cod.
(Figs. 144, 145.)

The size of the fifth nerve is very great, it
being by far the largest of those proceeding from
the medulla oblongata. In this respect it pre-
sents much variety according to the animal or its
class. M. Serres states that, the nerves being
proportioned always to the volume of the
organs from whence they proceed, the extent
of the face and of the organs of the senses
taken together gives the size of this nerve in
the different classes of vertebrate animals.
Among the Mammalia the extent of the face
and of the organs of the senses increases pro-
gressively from Man to Apes, the Carnivora,
the Ruminantia, and the Rodentia, and, ac-
cording to him, the size of the fifth nerves
follows in a general manner the same pro-
gression. Birds are remarkable for the atrophy
of the muscles of the face and of several of
the organs of the senses, and their fifth nerve
is far from presenting the developement to be
observed in the inferior Mammalia. Reptiles
are still lower than Birds with regard to the
dimensions of the nerves of the fifth pair;
while in Fish** the size of the nerve is very
great, and even surpasses in some the volume
it presents in the other classes.ft However just
the estimate of the comparative volume of the
nerve in different animals, as here stated, may

* Op. cit.

t Op. cit.

j Desmoulins, Journal de Physiologic, t. ii.
Serres, op. cit.

§ Desmoulins, Anatomie des Systemes Nerveux,
&c. Carus, Rudolplii.

|| riesmoulins, op. cit.

l" Desmoulins, op. cit.

** See Sketches of Nerve in the Ray and Cod,
figs. 144, 145.

tt Serres, Anatomic Comparee du Cerveau,
dans les quatre classes dcs Animaux Vertebres.

FIFTH PAIR OF NERVES.

2C9

be, the data, from which it is professedly
drawn, may be reasonably objected to. In
the first place the volume of the organ cannot
be assumed as being alone the measure of that
of the nerve supplying it • the degree of ner-
vous endowment, whether general or special,
which the organ enjoys, must be also taken
into account ; and in the second, the extent
of the organs of the senses cannot be admitted
as a measure of the volume of the fifth nerve,
which is not connected with them all ; thus
the greater part of the organs of touch is inde-
pendent of that nerve. It appears to me
that the extent of distribution and amount of
endowment conjointly determine the volume
of the nerve, and that the latter cannot be
inferred a priori.

Each nerve is composed of two portions,
which are remarkable for particular characters,
and have received distinct names ; they differ
from each other in size, in anatomical disposi-
tion, and in function ; one of them, larger than
the other, is provided with a ganglion, and dif-
fers in its distribution ; it also differs in proper-
ties, being subservient to sensation ; the other
is small, has no ganglion, and is destined to
volition ; they are hence denominated, the
former the larger, the ganglionic or the sentient
portion, the latter the smaller, the non-ganglio-
nic or the voluntary portion.

The distinction of the nerve into two por-
tions appears to prevail uniformly throughout
the animal series. According to M. Serres, it
is to be observed in all the classes of the ver-
tebrate animals except the Reptiles ; but in
them, according to him, the lateral fasciculi*
are wanting. The latter assertion, however, is
incorrect, the distinction being to be observed
as satisfactorily in that class as in any other.f
Again, the distinction is not equally remarkable
in all ; in some it is still more so than in man ;
in others it is less ; and according to the same
authority, it is to be observed among Mam-
malia the more easily as we pass from Man to
the Rodentia. Among the Cetacea it is divi-
ded throughout into two separate fasciculi. J

Each of the two portions of which the nerve
consists is a packet containing numerous fas-
ciculi, which are again divisible into filaments.
The fasciculi, of which the packets are com-
posed, are differently circumstanced in different
stages of the course of the nerve ; in one part
they are bound up so closely together that they
cannot without difficulty be separated from each
other and disentangled, while in another they
are but loosely connected and are easily sepa-
rated.

The two packets are associated together more
or less intimately throughout their course ; but
inasmuch as they present remarkable varieties
in their disposition and mutual relations at dif-
ferent parts, it may be advantageous to divide
the nerve, through its course, into three por-
tions or stages ; one from the ganglion to the
connexion of the nerve with the brain, which

* The uame by which he designates the lesser
portion of the nerve.

-f See sketch of fifth nerve in the Turtle,^. 143.
j Op. cit.

may be denominated its internal or encephalic
portion; a second from the ganglion to its ulti-
mate distribution, its external or peripheric
portion ; and, thirdly, its ganglion. Such a
distinction may not be free from objection, but
being adopted for the convenience of descrip-
tion, it possesses at least the recommendation
that there exist well-defined points of demar-
cation, whether there exist or not any difference
in the properties of those several portions. The
nerve, in its encephalic portion, is partly within
and partly superficial to the substance of the
brain. The superficial part is from one-half
to three-fourths of an inch in length, of a
flattened form, and of very considerable size.
It presents a loose fascicular texture, and is
enclosed within a prolongation of the arachnoid
membrane sent off upon it from the surface of
the brain ; this prolongation is, as in the case
of all those sent upon the vessels or nerves, in
their passage from that organ to the parietes of
the cranium, a cylindrical sheath, within which
the nerve is enclosed ; it is at first remarkably
loose, but as the nerve recedes from the brain,
the membrane invests it more closely, and is
continued upon it as far as the ganglion, from
which it is reflected to the surface of the canal
in which the nerve is contained. In the last
particular the disposition of the membrane is
subject to variety, for it is at times continued
beneath the ganglion, and partially invests the
trunks proceeding from this body before it is
reflected to line the canal.

Throughout this part of the nerve the two
packets composing it are connected by cellular
structure and vessels, and are enclosed within
the prolongation of arachnoid membrane just
described ; but there does not appear to be any
interchange of nervous filaments between them,
and they are connected so loosely that they can
be separated from each other with great facility.
They "consist each of numerous fasciculi held
together, like the packets themselves, so loosely
that the latter can be easily opened out and
decomposed. The fasciculi of both packets
are irregular in size, some large, others small ;
those of the larger are for the most part some-
what smaller than those of the lesser, but they
are much more numerous, amounting, accord-
ing to J. F. Meckel,* to thirty or forty; while
those of the lesser amount, according to the same
authority, only to from nine to fourteen. The
fasciculi again are composed of numerous and
delicate filaments. The number of the fila-
ments is very great, but differently estimated
by different authorities; according to Meckel
those of the greater packet amount to about
one hundred, collected into thirty or forty
fasciculi ; while, according to Cloquet,f the
total number of filaments contained by both
packets varies from seventy to one hundred,
of which he allots five or six to the smaller,
and the remainder to the larger packet. This
difference of opinion Meckel explains by sup-
posing that fasciculi have been taken for fila-
ments and not decomposed, and this appears

* Manuel d'Anatomie.
t Anatomic Descriptive.

270

FIFTH PAIR OF NERVES.

very probable, inasmuch as Cloquet takes no
account of fasciculi, and in his description of
the smaller packet it is manifest that he has
assumed the fasciculi, of which it is composed,
to be filaments, for he does not attribute to it
a greater number of filaments than it contains
of fasciculi. But if Cloquet have underrated
the filaments of the larger packet, Meckel
junior has certainly overrated the fasciculi of
the smaller one. From his account of the
latter, it is to be concluded that it contains
from three to fourteen fasciculi, but either of
those numbers is too great, as will be seen
from an examination of the subject, from which
it will appear that they do not exceed the
number attributed to them by Cloquet. The
ultimate number of filaments, however, would
seem to be somewhat uncertain, for it appears
to depend very much upon the delicacy with
which the separation of them may be effected ;
and after all it is not a matter of any great
importance. According to Wrisberg* and
Scemmerring-f the number of fibres contained in
the greater packet is always less in the foetus
than in the adult. The filaments of the smaller
are stated by Cloquet to be larger, softer, and
whiter than those of the other; but with regard
to the difference of size it is probable that
this opinion has arisen also from his having
assumed the fasciculi to be filaments, inas-
much as, when the fasciculi have been decom-
posed, the filaments seem to be equally fine in
both packets ; and for the other points of sup-
posed difference the author has not been able
satisfactorily to observe any in man. In other
animals, however, — in some fish at least — a
remarkable difference may be observed between
the characters of the ganglionic and non-gan-
glionic portions, the latter of which, in the
Cod, is much softer, and of a darker, not
whiter, colour than the other.

The fascicular and filamentous disposition
which has been described, is not, however,
presented by the encephalic portion of the
nerve through its entire extent, but only in
that part of it which is superficial to the brain ;
nor is it acquired by it until after it has emerged
one or two lines from the substance of the
organ, and then it does not assume it through-
out at once, but at first superficially and later
internally. The appearance of distinct fila-
ments and fasciculi in one part and their ab-
sence in the other appears owing to the exist-
ence of neurilema in the former, for in one
as in the other the nervous matter appears to
be arranged in longitudinal tracts, which pre-
sent in one case the form of expansions, and
in the other are divided by the neurilema
into separate cords ; and again the occurrence
of the filamentous disposition earlier upon the
surface than internally, is attributed to the
superficial substance of the nerve being pro-
vided with neurilema sooner than the inter-
nal ; hence the length of the substance of the
nerve without neurilema is greater internally

* Observations Anatomies de quinto pari ner-
vorum, &c.

t In Lmdvvig, Script, Ncurol. Min. Ueber das
Organ der Seele.

than externally, and when the nerve has been
pulled away from its attachment to the brain,
the rupture occurring at the point at which the
neurilema commences, the part which is left
projects in the middle, and presents a conical
eminence of white matter: this, as Cloquet
justly remarks, is but an incidental appearance,
and not entitled to be considered, as it was by
Bichat,* a real tubercle, from which the nerve
arose. In neither packet are the fasciculi
laid simply in apposition ; in both, but more
remarkably in the larger, they are connected
by frequent interchanges of filaments, and
that to such a degree that the nerve when
opened out appears to form an inextricable
plexus, in which it is not improbable that every
filament of it is connected directly or indirectly
with all the others; this plexiform arrangement
diminishes as the nerve approaches the gan-
glion, before reaching which the fasciculi be-
come more distinct.

The fifth nerve is attached to the surface of
the brain on either side of the pons Varolii, at
a distance of three-fourths of an inch from its
middle line. It is attached to the middle
cms of the cerebellum, on its anterior inferior
surface, about one-fourth of an inch from its
superior, and half an inch from its inferior
margin.

The place of the attachment of the nerve to
the exterior of the brain varies greatly in dif-
ferent classes of animals ; in man, it is, as has
been mentioned, the crus cerebelli on either
side of the pons; in the other orders of the
Mammalia it is either, as in the human sub-
ject, the crus cerebelli, or, when the pons is
less developed than in man, the nerve is at-
tached behind that part between it and the
trapezium of the medulla oblongata; in the
other three classes of vertebrate animals, in
which the pons and trapezium are both want-
ing, the nerve is uniformly attached to the la-
teral parts of the spinal bulb. This contrast
is equally curious and important ; it affords us
a natural analysis, which will throw much light
on the next step in our inquiry, viz. the origin
of the nerve, or its ultimate connexion with
the brain. It furnishes also, as has been sug-
gested by Gall and Spurzheim,f an explana-
tion of the complication which exists in the
human being, in whom the great developement
and the situation of the pons render it neces-
sary that the nerve should traverse it, in order
to reach the surface of the brain.

At the attachment of the nerve to the crus
cerebelli in the human subject, the non-gan-
glionic portion or lesser packet is situate above
and to the inner side of the greater. At that
place it is separated or separable into two
parts, while the greater continues undivided,
and hence the nerve is described as having
three roots, one for the greater and two for
the lesser packet. The existence of two roots
for the lesser packet had been announced by
Santorini^J but they have been more parti-

* Anatomie Descriptive.

t Anatomie et Physiologic du Systeme Nerveux.

J Observationes Anatomicae.

FIFTH PAIR OF NERVES.

271

eularly and accurately described by Palletta.*
They are distinguished by the latter into supe-
rior and inferior, being attached to the crus
cerebelli, one above and behind the other, and
they are frequently separated from each other
at their attachment by an interval of one or
two lines or more. In such case the superior
root is superior and parallel to the inner side
of the greater packet, while the inferior is in-
ternal to it, and, it may be, on a level with its
inferior surface; hence, in such instances, the
greater packet corresponds to the interval be-
tween the roots of the lesser, and the inferior
root of the lesser, in its course from the brain,
is placed at first along the inner side of the
greater packet, while the superior descends
internal to the greater packet, and joins the
inferior beneath it to constitute the lesser
packet. This is not, however, uniformly the
relation of the roots of the nerve at their at-
tachment to the crus, for the distance at which
they are placed from each other varies very
much; in some instances the roots of the lesser
packet are perfectly distinct and separated by
the interval mentioned, the inferior being either
in immediate contact with the greater packet,
and even entering the crus through the same
aperture, or being separated from it by an
interval varying, according to J. F. Meckel,
from a quarter of a line to a line; while in
others the roots of the lesser packet are not
manifestly distinct, but the fasciculi of which
they consist are attached to the crus in an un-
interrupted series reaching, from the attachment
of the greater packet, to within a line or less of
the posterior face of the crus, and separated
the one from the other by trifling intervals ; in
the latter case the lesser packet is, for the most
part, altogether superior to the greater at their
attachment. But even in this the lesser is still
distinguishable into two sets of fasciculi, which
take different routes through the substance of
the crus, one traversing it nearer to its ante-
rior, the other to its posterior surface. It has
been already stated that the lesser packet of
the nerve is characterized by the absence of a
ganglion ; it also has no connexion with the
ganglion of the larger packet, but passes it
without entering into it, and then becomes
attached to one of the trunks proceeding from
it; it is further maintained to be distributed
ultimately into those branches which are given
by the third division of the fifth to the muscles
of mastication. Pallettaf concluded from these
circumstances that it was a nerve distinct from
the remainder of the fifth ; and observing that
the superior root was principally consumed in
the temporal muscle, and the inferior in the
buccinator, forming the long buccal nerve,
he called the former the " crotaphitic," and the
latter the " buccinator" nerves. The distri-
bution of the lesser packet to the muscles of
mastication has been confirmed by Mayo J from

* Pallet'.a, De Nervis crotaphitico et buccina-
torio, an. 1784. Script. Neurol. Min. Select. Lud-
wig.

t Op. cit.

j Commentaries, and Physiology.

the dissection of the nerve in the ass. He
differs, however, from Palletta with regard to
its distribution to the buccinator, which he
denies : this point will come under considera-
tion again. It has been proposed by Eschricht*
to denominate it the masticatory nerve.

The place at which the nerve is attached to
the surface of the brain in the human subject
is to be regarded only as the point at which it
enters or emerges from the substance of the
organ, inasmuch as it can be, without difficulty,
followed to a much deeper part, and the fibres
of the crus, which are transverse to those of the
nerve, manifestly separate from each other, at
the entrance of the nerve, to allow it a passage.
The larger packet of the nerve is that whose
course into the brain can be most easily traced;
this circumstance depends partly upon the
greater size of the packet, and partly upon the
fact that, for the most part, its tracts are not
separated from each other by those of the crus,
but traverse that part in a body, the fibres of
the crus seeming to be simply laid in apposi-
tion with it, and connected to it by some deli-
cate medium ; while those of the lesser are, in
the greater number of instances, separated from
each other, or even interlaced with those of the
crus ; hence the fibres of the crus may be easily
raised, without injury to the nerve, from the
larger packet, and its course be displayed,
while the lesser cannot be followed but with
difficulty. The larger is, however, subject to
variety in the latter respect ; in many instances
the fasciculi of the crus do traverse and divide
it, and very frequently near its ultimate attach-
ment, and this circumstance, when it occurs,
renders the pursuit of its course more difficult ;
but even here the fasciculus merely traverses
it, and its tracts are not permanently separated,
but reunite after the fasciculus has passed.
The course of the packet may be exposed to a
considerable extent even in the recent brain ;
but for the satisfactory determination of the
point, it is necessary that the brain be prepared
by some of the methods recommended for that
purpose, of which immersion in strong spirit is
by far the best, nor does it require much time,
for the substance will be found to separate
more easily when it has acquired only a certain
degree of firmness, than when hardened to the
degree which long immersion produces; the
plan which the author has found most success-
ful has been to commence the dissection early,
to return to it frequently, and at each time to
pursue it so far and so far only as it was satis-
factory. The course of the larger packet is
also beneath and before that of the lesser, and
hence, in the usual mode of dissection, in which
the brain is reversed, it presents itself first.
Its direction is backward, downward, and in-
ward, toward the upper extremity of the spinal
bulb ; in its course the packet first traverses
the middle crus of the cerebellum from its an-
terior toward its posterior surface, and from its
superior toward its inferior margin ; it pursues
this course until it has reached the back of the
crus, and descended so low as its inferior mar-

* Journal de Physiologic, t. vi.

272

FIFTH PAIR OF NERVES.

gin ; it is then situate in the angle formed by
the three peduncles of the cerebellum at their
junction with the hemisphere; behind the
middle, beneath the superior and above the in-
ferior, and before, or in common language, be-
neath the floor of the fourth ventricle. Thus
far the course of the nerve may be ascertained
without much difficulty; it is probably the
same point to which Santorini had traced it,
as described in his ' Observationes Anatomicae,'
in 1724, and from which Soemmerring has
more expressly stated it to be derived, in his
work * De corporis human! fabrica/ pub-
lished 1798, in which he states "that it ap-
pears to arise almost from the very floor of the
fourth ventricle." * At the point last described

Fig. 140.

Lateral view of the pans, spinal bulb, and course of
the Fifth Nerve in man.

1 Pons Varolii.

2 Spinal bulb.

3 Olivary body.

4 Spinal cord.

5 Superior peduncle of cerebellum.

6 Cut surfaces of middle ditto.

7 Inferior peduncle of cerebellum.

8 Cut surface of crus cerebri.

9 Ganglion of Fifth Nerve reversed.

10 Ganglionic portion of the nerve.

1 Non-ganglionic portion of Fifth Nerve.

11 Roots of non-ganglionic portion.

12 Eminence at the insertion of both portions of

the Fifth Nerve.

13 Fasciculus to anterior column of spinal cord,

14 Fasciculus to posterior column.

15 Auditory nerve.

16 Portio dura.

17 Posterior roots of superior cervical nerves.

* Santorini, however, appears to have followed
the nerve out into the spinal bulb, though, as will
be seen, he did not succeed in determining its real
and ultimate connection.

the greater packet is attached to the side of the
medulla oblongata. The point of attachment
is very close to the interior of the fourth ven-
tricle, being separated from it only by a thin
lamina, which is little, if any thing, more than
the " epithelium" of Reil : it is situate in the
angle formed by the peduncles of the cerebel-
lum, behind the middle one, by the outer
margin of the pons, and posterior to it, and
above its lower one : it is also superior to the
attachment of the auditory nerve, separated
from it by an interval of some lines.

We shall, in the next place, direct attention
to the course and connection of the lesser
packet of the nerve.

In none of the authorities which the author
has had an opportunity of consulting, has he
found a particular origin assigned to the lesser
packet. By most anatomical writers it is over-
looked; J. F. Meckel states that it can be
traced a certain way into the crus, but he
goes no further; Mayo asserts that the lesser
portion arises close upon the greater, and, in a
sketch of the origins of the nerves given by him
in his Physiology, it is represented traversing
the crus cerebelli, as a single fasciculus, above
and behind the greater, and attached to some
part above that from which the greater is re-
presented to arise : but still the origin is not
defined, and it is manifestly intended to be
distinct from that of the greater packet.

The author has succeeded, as it appears to
him, satisfactorily in tracing both the roots of
the lesser packet to a destination for which he
was not prepared ; at setting out he expected
to have found the origin of the lesser different
from that of the greater packet, and to have
followed it to a prolongation of the anterior
columns of the spinal cord, as has been stated
by Harrison ;* it was therefore with surprise
that, after a patient dissection, he succeeded in
tracing both its roots to the same point, to
which the greater packet is attached, behind
the middle crus of the cerebellum (see Jig. 140,
12); both the roots traverse the crus, as the
greater does, the inferior very frequently in
company with and internal to the greater
packet, or separated from it by a very thin
stratum of the substance of the crus, the
superior near to the superior surface of that
part, and separated from the greater packet by
an interposed stratum of two or more lines;
the course of the latter is so near to the surface
of the crus, that it can frequently be traced for a
considerable way by the eye without dissec-
tion : they present, in their mode of traversing
the crus, two remarkable varieties ; in some in-
stances the fasciculi, of which they are com-
posed, are separated from each other and even
interlaced with those of the crus, and in such
the pursuit of them is intricate and difficult;
in others they pass in two distinct packets, and
in these they are more easily followed. As
they proceed they approach the greater packet,
so that the interval between them and it gradu-
ally diminishes, and having traversed the crus,
they are both attached below and behind it to

* Dublin Dissector.

FIFTH PAIR OF NERVES.

273

the same part as the greater packet, and poste-
rior to it. (See jig. 140). This view of the con-
nection of the lesser packet, if confirmed, must
lead to interesting results with regard to the rela-
tions of the two portions of the fifth nerve at least;
it will at all events decide the question as yet in
dispute, whether they are to be regarded as
distinct nerves, or parts of the same ; upon
this point further light will be thrown by the
disposition of the same part in fish, in which
the source of the uncertainty prevailing with
regard to the nerve in the higher classes does
not exist to the same amount ; inasmuch as the
ganglionic and non-ganglionic divisions of the
nerve seem for the greater part associated in
their distribution.

Fig. 141.

Back view ofpons, bulb, and course of the Fifth
Nerre in man.

18 Tubercula quadrigemina.

19 Continuation upward of the tract from which

the Fifth Nerve arises.

The other references indicate the same parts as
in the preceding figure.

"When the adjoining matter has been care-
fully cleared away from the part to which the
packets of the nerve are attached, that part ap-
pears to be a longitudinal tract of a yellowish-
white colour, composed of fibres running in the
same direction, and capable of being followed
both upward and downward : upward this tract
seems continued beneath the superior peduncle
of the cerebellum;* downward it descends from

* Of the nature of the structure continued up-
ward from the attachment of the nerve the author
is not satisfied : it presents, when cleared, the ap-
pearance given to it in fig. 141 , 19, but it is very cine-
ritious in character, and he is not prepared to say
whether it be a continuation of the tract from which
the nerve appears to arise, or a part of the floor of
the fourth ventricle at its upper extremity, con-
nected to the attachment of the nenre : the mode
in which the nerve arises in the bird and the turtle
appears to the author opposed to the opinion that
the tract to which the nerve is attached is, in them
at least, any thing more than a continuation or
VOL. II.

behind the pons into the spinal bulb, and after
a short course divides into two cords, one for
each column of the spinal marrow (see Jigs.
140, 141). At the entrance of the tract into
the bulb it is situate deep, before the floor of
the fourth ventricle and behind the superficial
attachment of the two portions of the seventh
pair, which must be separated from each other
and displaced in order that it may be ex-
posed : externally the tract corresponds to the
peduncles of the cerebellum, and is united in-
ternally to the cineritious matter of the floor
of the ventricle. At the point of attachment
the tract presents a somewhat prominent en-
largement, (figs. 140, 141, 12,) which the au-
thor will venture to call an eminence, though
with hesitation, lest it be considered an ex-
aggeration, from which the nerve may be held
to arise.

It is said that the nerve may be held to arise
from this tract, because, though it be certainly
not its ultimate connection with the brain, and
though cords can be traced from it to more
remote parts, yet the union of the cords at the
point, and the attachment of both portions of
the nerve to it, seem to mark it as the origin
of the nerve ; the change of character too which
will be described as occurring at the attach-
ment of the nerve, countenances the opinion
that the tract is not simply a continuation of
the nerve.

It may be doubted whether the eminence
really exist, or whether it be not merely the
result of dissection : the author will not insist
upon it, but several considerations induce him
to consider it real : in the first place, he almost
uniformly finds it,* and secondly, it seems to
be a common point to the two portions of the
nerve and to the other cords, which form part
of its encephalic connections ; and lastly, this
view is corroborated by the disposition of the
same part in other animals ; for a similar ap-
pearance will be found, at the attachment of
the nerve behind the pons, in other mammalia
as well as in man after the separation of the
adjoining matter, e.g. in the horse; and it is
even asserted by Desmoulins that an eminence
may be observed naturally upon the floor of
the fourth ventricle, in some animals, at the
attachment of the nerve. His statement is :
" on observe meme dans les rongeurs, les
taupes, et les herissons, un petit mamelon ou
tubercle sur 1'extremite anterieure du bord du
ventricule ; mamelon, dans lequel se continuent
les fibres posterieures de la cinquieme paire, et
de 1'acoustique." When the tract has reached
the point at which the inferior peduncle of the
cerebellum first inclines outward toward the
hemisphere, it separates, as has been stated, into
two parts or cords, (seejigs. 140, 141,) destined,
one, as is already known, to the posterior, the
other, according to the author's belief, to the an-
terior column of the spinal cord. The course and
disposition of these cords are remarkable and

root of the nerve, but admitting this, he cannot
satisfy himself that it is to be regarded in the same
light in the Mammalia.

* The attachment of both the packets must be
made out, else the enlargement will not appear.

I

274

FIFTH PAIR OF NERVES.

apparently contrary to analogy ; they are dis-
tinguishable into anterior and posterior, but
they descend, the anterior to the posterior, and
the posterior to the anterior columns. The an-
terior cord is by much the larger, and is pro-
longed through the inferior peduncle of the
cerebellum, until at the inferior extremity of
the bulb it is continued into the longitudinal
fasciculi of the corresponding posterior column
of the spinal marrow ; it is situate along the
outer side of the olivary body, but separated
from it by a slight interval, nor does it seem
to have any connection with that body : it is
imbedded in the substance of the superior part
of the peduncle, situate, however, nearer to its
anterior than its posterior surface, and laid
obliquely across its fibres as they pass outward
toward the hemisphere of the cerebellum ; but
as it proceeds it becomes gradually more super-
ficial, gains the outer side of the peduncle, and
at the lower extremity of the bulb is actually at
its surface almost immediately behind the lateral
fissure of the cord and the posterior roots of the
superior cervical nerves. The existence and
course of this cord have been first established
and described by Rolando in his "Saggio sopra
la vera Struttura del Cervello," and also in a
memoir upon the Anatomy of the Medulla
oblongata, published in the fourth volume of
the Journal of Physiology.

The posterior cord is much smaller than the
former ; it descends behind the inferior pedun-
cle of the cerebellum, as it passes outward
into the hemisphere, and upon the posterior
aspect of the spinal bulb ; enters the posterior
fissure of the bulb, between the posterior py-
ramids, and can be traced some way down-
ward, in the bottom of the fissure, along the
back of the anterior column of the same side,
into which it appears to be ultimately con-
tinued. (Figs. 140, 141, 13.)

The preceding account of the encephalic
connections of the fifth nerve differs very much
from that adopted by some of the highest
modern authorities. It is not necessary to
allude to the opinions entertained upon the
point, before the course of the nerve had
been particularly inquired into; but, accord-
ing to some of the most recent, the nerve
arises from the groove between the restiform
and olivary bodies, and from the olivary bodies
themselves. Such is the view given of the
origin of the nerve by Gall and Spurzheim
in their fifth plate of the brain, in which the
nerve is represented breaking up, on the out-
side of the olivary body, into several fasciculi,
which plunge obliquely into it. In their
account* of the course of the nerve into the
brain they state, " on peut ai semen t suivre son
cours entier jusq'au dessous du cote exterieur
des corps olivaires ;" this might be, perhaps,
interpreted to mean beyond the olivaries,
reference being had to the relations of those
bodies in the erect posture ; but from the
representation given it is obvious that the in-
tended meaning is, that the nerve can be fol-

* Anatomic et Physiologie du Systeme Ner-
venx, torn. i. p. 107.

lowed to beneath, i. e. underneath, their outer
side, the brain being placed in the manner
ordinarily adopted for dissection, in which
the anterior aspect of the olivaries is rendered
superior; indeed their representation is alto-
gether incompatible with the opinion that they
had traced the nerve beyond the bodies.

Such also is the opinion of J. F. Meckel,*
according to whom the nerve " passes under
the posterior peduncle of the cerebellum,
along the outer side of the pons, toward the
groove between the olivary and restiform bo-
dies, where it arises in part from the groove
and in part from the olivary eminences."
Cloquetf likewise states the nerve to arise
between the olivary and restiform bodies, and
has adopted and copied, in his late work,f
the view given of its origin by Gall and Spurz-
heim. Further, the discovery of this origin of
the nerve has been attributed by Meckel § and
others to Santorini.

It is a hardy thing to contradict such au-
thorities as have been quoted, and the influence
which they justly carry with them has made
the author" hesitate before adopting a contrary
opinion ; but if reference be made to the workj)
of Santorini on the point, it will be found that
he nowhere, in his account of the origin of the
nerve, assigns the groove between the restiform
and olivary bodies as its situation in the spinal
bulb, as will appear from the following extract,
the only paragraph of his account in which he
particularizes it, and in which he supposes it
to be situate between the olivary and pyramidal
bodies : " Unde in interiorem medullae ob-
longatae caudicem conjectus, fere inter olivaria
et pyramidalia corpora locatus, quo demum
pergat, cum tenuium fibrarum implexus, turn
earumdem mollitudo, ne consequerer, omnino
prohibuere ;" from which it is plain, as has
been stated, that he supposed the nerve to be
between the two latter bodies ; and also that
he had not been able to trace it to any particular
destination, although, in a succeeding para-
graph, he conjectures the olivary body to be
its source : hence there is reason to conclude
that succeeding anatomists have assumed his
conjecture to be an established fact, and have
modelled their accounts and representations
accordingly. Moreover, since the olivary bodies
do not exist in the lower classes of animals,
it is not likely that they should be points of
origin or attachment for nerves ; in fine, the
author has so uniformly succeeded in tracing
the nerve to the destination which has been
described, that he is satisfied of the accuracy
of it, in which he is confirmed by the fact that
the account here given accords with the opinions
of Santorini, Soemmerring, and Rolando, so
far as that of the first has been determined to
be accurate, or as those of the others extend :
the particulars in which it differs from, or rather
in which it goes beyond these, rest upon the
author's authority and remain to be confirmed,

* Manuel d'Anatomie, French edit,
t Traite d'Anatomie descriptive.
| Anatomie de 1'Homme.
§ See note 5, p. 82, op. cit. vol. ii.
[| Observationes Anatomic*. •

FIFTH PAIR OF NERVES.

275

viz the attachment of the two packets to the same
point, the existence of the eminence at the inser-
tion, and that of a cord of communication with
the anterior column of the spinal marrow.

The encephalic connections of the nerve,
as detailed, are corroborated by those to be
observed in inferior animals. In those Mam-
malia in which the pons is but little deve-
loped, the nerve is attached between that part
and the trapezium; in those instances in which
the pons is more so, the nerve is attached,
superficially, not actually behind that part,
but near to its posterior margin; with little
trouble it can be followed to the back of the
pons, where it is attached, as in Man, to the
medulla oblongata, the point of attachment
presenting here also, after the separation of the
adjoining matter, the appearance of an emi-
nence or tubercle, from whence a cord de-
scends beneath the trapezium into the lateral
column of the spinal bulb. This cord is of
great size in many animals ; and in some can
be seen distinctly, without dissection, upon
the surface of the spinal bulb, in consequence
of the degree to which it projects : it is well
expressed in the delineation of the brain of the
calf in the third plate of Gall and Spurzheim,
and in that of the brain of the horse in fig. 275
of M. Serres' Illustrations of the Comparative
Anatomy of the Brain.

In Birds, Reptiles, and Fish, neither pons,
trapezium, nor olivary bodies exist, and the
nerve is attached to the lateral part of the
spinal bulb at its superior or anterior extremity,
and to its lateral column — the prolongation of
the superior column of the spinal cord. In
all three the point of attachment is situate a
little way from the back of the bulb and be-
neath the floor of the ventricle, the cineritious
stratum, of which the latter consists, being
directly connected to the back of the nerve.
In Birds (Jig. 142) the continuation of the nerve

Fig. 142.

can be traced downward along the side of the
bulb toward the spinal cord, and without diffi-
culty, inasmuch as it is superficial and is not
crossed by a trapezium, as in the Mammalia.

In the Turtle the nerve can be traced in like
manner from the point of attachment down-
ward into the lateral column ; and in Fish the

Fig. 143.

Brain and Fifth Nerves of the Goose.

1 Inferior surface of cerebrum.

2 Spinal bulb. 3 Ganglia of fifth nerves.

4 Root of nerve from lateral column of the bulb
exposed by turning aside the superficial stratum of
that part.

5 First division of the fifth. 6 Second do.
7 Third do. 8 Auditory nerve.
On one side (the reader's right) the non-gan-

glionic fasciculus has been traced beneath the gan-
glion into the third division of the nerve.

Origin of nerve in Turtle.

1 Spinal bulb.

2 Fifth nerves.

The pin is passed between the ganglionic and
non-ganglionic fasciculi, the latter being continued
into the third division.

3 Ganglion.

4 First division of the nerve.

5 Second do.

6 Third do.

attachment is in all essentials similar : the com-
parative small ness of the bulb and the direc-
tion which the nerve takes in its course out-
ward, make it resemble the spinal nerves more
than in the other classes ; but its encephalic
connection is strictly the same, namely, to the
lateral column of the bulb beneath the floor of
the ventricle. In the Cod, after the removal of
the floor of the ventricle from the back of the
nerve, the latter may be followed for some way
into the column, though neither to the same
extent nor so satisfactorily as in the bird or the
Turtle; and in the Ray, while the two inferior
fasciculi of the nerve — for in this fish it consists
originally of three — are connected in the usual
mode to the lateral column, the superior is
attached to a convolution formed by the floor,
in consequence of a greater developement of its
margin. In the Cod the convolution adverted
to does not exist, but the floor of the ventricle
cannot be raised from the nerve without destroy-
ing a connection of some kind between them.
In the latter fish the fifth nerve is attached
before and rather superior to the auditory nerve,
and the two nerves are quite distinct as far as
the point of attachment, but there they are in

T2

276

FIFTH PAIR OF NERVES.

Fig. 144.

'Brainand Fifth Nerves of the Cod.

1 Non-gangl ionic portions (on the reader's left
side) separated from the gang! ionic and thrown
back.

2 Ganglionic portion.

a First branches of both portions.
b Second do. 't

immediate apposition and appear to have the
same source. In the Ray it is different; in it
the auditory seems merely a branch of the
fifth (Jig. 145, 7) given off from its posterior

c Third do.

d Fourth branch derived from both.
e Fifth branch derived only from the ganglionic.
The third division has been removed on the left
side.

ganglionic fasciculus about three lines from its
attachment to the spinal bulb, and before the
formation of its ganglion.

After the preceding details it must seem

Fig. 14.5.

Brain and Fifth Nerves of the Ray.

a Anterior ganglionic portion of the fifth nerve. posterior ganglionic ; on the right it is in situ.
6 Posterior do. e First branches of the two portions.

c Non-ganglionie portion. On the reader's left f Second do.

it is laid back to display its connexion with the

Auditory nerves.

extraordinary if the nerve in the higher ani- the brain, so very much from that in the in-
mate differed, in its ultimate connection with ferior, as it is represented by some to do.

FIFTH PAIR OF NERVES.

277

Yet it is asserted by M. Serres,* who has
founded his opinion upon the observations
which he has made upon the successive de-
velopement of the brain and nerves in the
embryo of vertebrate animals, that in the
Mammalia the nerve is implanted upon the
trapezium. Such is the form of expression by
which he intends, as the author understands,
the ultimate connection of the nerve with the
brain. Now, in the first place, we hare al-
ready seen where that connection is in those
animals in which the trapezium does not exist,
and it appears to the author reasonable to con-
clude that similar nerves have similar or ana-
logous attachments in the several classes of
animals, however the parts with which they
are connected may be complicated or ob-
scured by superadded structures. In the second
place the trapezium can be regarded only as a
superadded structure, and is not among those
parts from which nerves are likely to arise,
being itself but a commissure : and, thirdly,
the situation and connections of the part to
which the nerve is attached, are altogether in-
compatible with the opinion that it is the tra-
pezium, inasmuch as the latter is situate be-
fore the cords, which ascend from the anterior
columns of the spinal cord to the crura cerebri,
while the structure with which the nerve is
connected is posterior to them. For these
reasons the author concludes that M. Serres
has mistaken the place of the nerve's attach-
ment in the Mammalia.

In conclusion, the representation of the ori-
gin of the nerve, which appears to the writer to
be the most remote of all from the real one, is
that given by Swan, in his plates of the nerves
lately published, in which the fifth is re-
flected into the auditory nerve : such a con-
nection is merely artificial and does not really
exist ; it can be produced only by stopping short
in the pursuit of the fifth nerve, and mould-
ing it into the anterior root of the auditory,
which is in contact with it.

This view of its encephalic attachment has
probably originated in the intimate connection
known to exist between the two nerves in in-
ferior animals. The complication of the cere-
bral connection of the nerve in the higher
animals may be now better understood. In
those, in which the pons and trapezium do not
exist, the nerve emerges directly from the
spinal bulb, in a manner similar to the ad-
joining nerves ; but in those, in which the
bodies alluded to are present, inasmuch as the
attachment of the nerve is behind them, it can
reach the surface only by either passing be-
tween them, or traversing their substance.
Hence, if the nerve simply traverse them, it
ought not to receive any accession of fibres from
them, and such, according to the writer's
experience, is the case. As it emerges from
the pons, the lesser packet receives an epithe-
lium from its surface; but he has not been
able to detect any fibres originating within the
substance of that part.

The structural arrangement, which the ence-

* Op. cit.

phalic portion of the nerve presents within the
brain, is different from that, for which it is
remarkable, while superficial to it. Exter-
nally it is, as has been stated, of a fascicular
texture ; but, within, that appearance is not to
be observed: there the larger portion- is a
white, soft, homogeneous, flattened cord, the
delicacy of which, in the natural state, forbids
the separation of it into distinct parts ; but
when sufficiently hardened, it may be divided
into numerous thin strata, and these again into
delicate fibrils. That such an arrangement is
a natural, and not an artificial appearance, is
manifest from the circumstance, that the sepa-
ration into fibrils can be effected only in one
direction, the length of the nerve, and that
they break off when it is attempted in the
other. The nerve retains those characters as
far as its attachment behind the eras, but there
they cease ; the pure white colour suddenly
disappears ; the point of attachment and the
cords descending from it present a cineritious
tint ; and they are not absolutely distinct from
the surrounding substance, as the nerve had
previously been, but immersed in it ; they are,
however, still manifestly composed of fila-
ments, which may be rent either toward or
from the point of attachment ; and after im-
mersion in spirit they become nearly white.
The course of the nerve, from its attachment
to the surface of the brain, is forward and out-
ward toward the internal anterior extremity of
the petrous portion of the temporal bone ; it
next passes over the superior margin of thai
portion, and descends upon its anterior surface
into the middle fossa of the base of the cra-
nium, where it reaches the Gasserian ganglion..
During its short course, from its attachment to
the brain, to the ganglion, it is at first contained
within the proper cerebral cavity, by the side
of the pons Varolii, and beneath the internal,
anterior angle of the terrtorium cerebelli ; in
the second place, in the middle fossa, it is-
not within the cerebral cavity of the cranium,
but beneath it, separated fro-n it by a lamina
of dura mater ; it is there contained in a canal1
or chamber, formed by a separation of the
dura mater into two layers, between which the
nerve and its ganglion are inclosed, one be-
neath them attached to the bone, another above
separating them from the brain. This chamber
is situate immediately external to, and lower
than the cavernous sinus, but separated from
it by the inferior lamina of the dura mater just
described, which ascends from the bone to
join the superior, and in so doing forms a
septum between the two chambers ; it is about
three-fourths of an inch long, reaching from
the superior margin of the petrous bone to the
anterior margin of the depression upon its
anterior surface, in which the ganglion rests.
In front this chamber is wide, containing at that
part the ganglion, and sends fibrous offsets upon
the nervous trunks proceeding from it; poste-
riorly it is narrow, and presents an oval aperture,
about one-third of an inch long, situate ex-
ternal and inferior to the posterior clinoid pro-
cess of the sphenoid bone beneath the attach-
ment of the tentorium cerebelli to that

278

FIFTH PAIR OF NERVES.

and also beneath the superior petrous sinus :
by this aperture the chamber communicates
with the cerebral cavity and the nerve enters.
The chamber is lined by the arachnoid mem-
brane, as far as the posterior margin of the gan-
glion, but along this the membrane is reflected
from the interior of the chamber to the nerve,
and returns upon it into the cranium: hence
the nerve is free within the chamber, while
the dura mater is attached to the surfaces of
the ganglion, and so closely that it requires
care to separate it from them. The cham-
ber presents a remarkable variety in its con-
struction in some animals: in the horse, for
instance, its parietes are not simply fibrous,
as in man, but, frequently at least, in great
part ossecus, being at the same time lined by
the membrane.

The passage of the nerve over the margin
of the petrous bone is marked by an inter-
ruption in the sharp edge, which the bone
presents external to that point, and its site
upon its anterior surface, as also that of the
ganglion by a corresponding shallow depres-
sion.

Throughout the course of this portion of
the nerve, the relation of the two packets
to each other varies ; at the attachment of the
nerve to the crus cerebelli, the smaller packet,
allowance being made for those varieties pre-
sented by it in its mode of attachment, is
superior and internal to the larger ; in the in-
terval between the crus and the margin of the
petrous bone, the smaller packet gradually
descends along the inner side of the larger,
until it has reached the same level, so that the
two packets are placed immediately side by
side upon the margin of the bone, the lesser
internal to the greater ; but as the nerve pro-
ceeds into the middle fossa, the smaller, at
the same time, passes from within outward
beneath the larger, and also beneath the gan-
glion, toward its outer and posterior extremity;
during this course it has no communication
with the ganglion, but is quite distinct from
it, though inclosed in common in the chamber
formed by the dura mater, and connected with
it by a dense cellular or fibrous structure; but
having thus passed the ganglion, the lesser
packet is united to the third trunk proceeding
from that body, and with it constitutes the third
division of the nerve.

The larger packet, on the contrary, is at-
tached to the ganglion. It has been before
stated that the plexiform arrangement, which
it presents, becomes less, as it approaches that
body; its fasciculi become more distinct; they
separate from each other, so that the width of
the packet is greatly increased, and having
reached the posterior margin of the ganglion
they are received into the channel which it
presents ; in which they are ranged, in series,
from one extremity of the body to the other,
overlapped by its edges, and enter abruptly into
the substance of the ganglion.

External portion of the nerve. — The external
orperipheric portion of the nerve consists of three
large trunks or divisions, which are connected,
on the one hand by their ramifications, with the

organs to which the nerve is distributed, and
on the other, with the ganglion and the brain.
They are distributed, generally speaking, to
three different regions of the head and face,
one to the uppermost, another to the middle
or superior maxillary, and the third to the
lowest or inferior maxillary regions, and they
are denominated, either numerically, first,
second, and third, as by the first Meckel; or,
according to the parts to which they are dis-
tributed, the first the ophthalmic, by Willis;
the second the superior maxillary, and the
third the inferior maxillary, by Winslow.
These methods of distinction have their several
advantages. Could we select names which
would give adequate ideas of the distribution
of the "trunks, the latter would certainly be
preferable; but inasmuch as those which have
been selected do not at all adequately express
that distribution, and are attended, therefore,
with the inconvenience of not giving a suffi-
ciently enlarged idea thereof, it would probably
have been better, had the former been from
the first adopted and adhered to, for such
names could not create any incorrect impression
with regard to the distribution of the several
divisions of the nerve; in fact, the epithets
ophthalmic, superior, and inferior maxillaries
ought to be altogether discarded, for, beside
the objection to their use already stated, it will
be found, upon reference to the anatomy of
other animals, that they are by no means dis-
tinctly appropriate, and that the circumstances
upon which they are founded are purely inci-
dental, associated with the peculiarities of the
animal ; for the proof of which, see the com-
parative disposition of the fifth nerve in the
several classes.

The three trunks differ from each other in
size. The first, the ophthalmic, is the smallest;
the second, the superior maxillary, is inter-
mediate in size; and the third, the inferior
maxillary, is by much the largest. They are
connected to the anterior convex margin of the
ganglion, — the first to its superior internal
extremity, the second to its middle, and the
third to its inferior external extremity. At their
attachment they are wide, flattened, and of a
cineritious tint; but as they proceed they
become contracted in width, cylindrical or oval
in form, and of a white colour. Their texture
is fascicular and compact, the fasciculi of which
they are composed being bound up closely
together, and they differ remarkably in com-
position, the two first, the ophthalmic and
superior maxillary, being derived altogether
from the ganglion, and thus being, in anato-
mical constitution, simple ; whereas the third
is composed of two parts, one derived from
the ganglion, and another formed by the lesser
packet of the nerve, which does not join that
body, and hence that division is compound.

The trunks rest partly against the outer side
of the cavernous sinus and in part upon the
base of the cranium in its middle fossa, and
they are enclosed in offsets from the fibrous
chamber, in which the ganglion is contained.
Their relative position corresponds to the posi-
tion of the ganglion; the' first is superior and

FIFTH PAIR OF NERVES.

279

internal to the other two, the second is inferior
and external to the first, and the third is exter-
nal, posterior, and inferior to both the others.
They go off from the ganglion at different
inclinations, the first forward and slightly
upward, the second directly forward, and the
third almost directly downward; hence the
first and second form a very acute angle with
each other, while that between the second and
third is much greater.

First or ophthalmic division. — This division
is distributed to the eye and its appendages,
to the nostril, and to the forehead. It is the
smallest of the three trunks proceeding from
the ganglion, and is situate superior and inter-
nal to the other two. It is about three-fourths
of an inch long from the ganglion to its division
into branches, and is contained thus far within
the cranium. Its course is forward, upward,
and slightly outward toward the upper part of
the foramen lacerum of the orbit. It is laid
against the outer side of the cavernous sinus,
in company with the third and fourth nerves,
and is contained in the external wall of the
sinus, being separated from the interior of that
chamber by a thin septum, which is a prolon-
gation of the inferior internal wall of the canal
in which the nerve and ganglion are contained.
The septum is dense, but at the same time so
thin and transparent that the nerve can be seen
through it from the side of the sinus, while the
lamina of the dura mater, by which it is sepa-
rated from the interior of the cranium, is so
thick and opaque, that the course of the nerve
is altogether concealed from that side. At its
outset the nerve is beneath, and external to the
third and fourth nerves, and external and some-
what superior to the sixth, which is within the
sinus; but ascending as it proceeds, it gains,
about the middle of the sinus, the same level
with the third, placed still at its outer side,
and inferior to the fourth, and then terminates
by dividing into branches.

Presently after its origin from the ganglion
the nerve is joined by one or more very fine
filaments from the sympathetic: this is ex-
pressly denied by the first Meckel, but he was
certainly mistaken; they are very faithfully
represented by Arnold. In order to display
them the sixth nerve may be separated carefully
from the carotid artery in the cavernous sinus,
after which it will be found that branches of
the sympathetic ascend upon the artery internal
to that nerve, and distinct from those which
are connected with it. Having surmounted it
they branch off, some upon the artery as it
passes to the brain, others to other destinations,
and of the latter some incline outward above
the sixth nerve and are connected to the first
division of the fifth : they are short and very
delicate.

The first division of the fifth gives off no
branch from its outset to its final division,
except an extraordinary filament described by
Arnold, and denominated by him the recurrent
branch of thefrst division of the fifth . It arises
from the upper side of the trunk immediately
after it leaves the ganglion^ runs backward above
this body at a very acute angle, enters the struc-

ture of the teutorium cerebelli, and divides be-
tween its laminae into several very delicate fila-
ments.

The branches into which the first division of
the fifth ultimately divides are either two or three;
according to the elder Meckel and the greater
number of authorities they are three ; according
to others they are sometimes three, but are more
frequently only two. The three branches are
the frontal, the nasal, and the lachrymal.
When the branches are but two, they are,
according to J. F. Meckel, the nasal and the
frontal, the latter in such case giving off that,
which in the other mode of distribution is the
third, the lachrymal. The elder Meckel attributes
the difference of opinion which prevails with re-
gard to this point to the fact that the lachrymal
nerve frequently has a second root derived
from the frontal, which in such cases has been
assumed to be the origin of the nerve. The
names which have been applied to those
branches have been taken either from their
destination or from their relative course ; thus
the frontal, so called from its distribution to
the forehead, is also called the superior or
middle branch; the nasal, so called because
finally distributed to the nostril, the internal
or inferior, and the lachrymal, which derives
its name from the lachrymal gland, the external.
The three branches differ in size ; the frontal is
considerably larger than either of the others,
the nasal is second, and the lachrymal is much
the smallest. They all three traverse the orbit,
but they pursue different routes, and have, at
entering, very different relations.

1. The frontal nerve appears in the human
subject, both from its size and its direction, to be
the continuation of the original trunk. In other
animals, however, it is otherwise : in them the
predominance of the frontal nerve diminishes
along with that of the superior region of the
face, until in some it ceases to exist as a pri-
mary branch of the first division of the fifth,
and its place is supplied by a secondary branch
of another, while the nasal branch increases
in the same proportion, and seems ultimately
to constitute itself the first division of the fifth.*
The frontal nerve passes upward and forward
toward the highest part of the foramen lacerum
of the orbit, and enters that region through it.
It then continues its course through the orbit
to the superciliary foramen and escapes through
it to the forehead. During this course it is
placed, before it has entered the orbit, at the
outer side of the third nerve; it then rises
above the third and crosses over it to its inner
side. In doing so it is accompanied by the
fourth nerve, to which it is external and in-
ferior; it enters the orbit in company with
the fourth and nearly on the same level, but
still external to and somewhat beneath it. In
entering, it passes above the origin of the
superior rectus muscle, and all the other parts
transmitted through the foramen lacerum, with
the exception of the fourth nerve. At the en-
trance of the frontal nerve into the orbit and
during its course from its origin thereto it is

* See comparative distribution of the fifth ucivc.

280

FIFTH PAIR OF NERVES.

closely attached to the fourth nerve, but pre-
sently after separates from it, the fourth in-
clining inward, is continued forward to the
superciliary foramen, lying upon the superior
surface of the superior rectus and levator palpe-
brae muscles, being through its whole course
within the orbit immediately beneath its roof.
Having reached the foramen it passes through
it, and changing its direction, ascends round
the superciliary arch, upon the forehead, be-
neath the orbicularis palpebrarum and frontalis
muscles, and is thenceforth called by some the
external frontal nerve in contradistinction to a
branch from itself, the supra-trochlear,or internal
frontal. In its mode of escape from the orbit
the frontal nerve is subject to some variety,
consequent in part upon the mode in which
the superciliary foramen is formed, that being
in some instances altogether osseous, in others
osseous only at its superior part and completed
by ligament below; in this case the nerve
escapes through an osseous notch, and not a
foramen. In other instances, again, when the
nerve divides previous to its escape it is some-
times transmitted through two apertures.

The distribution of the frontal nerve, as well
as that of most of the secondary branches, is
subject to varieties, which the author has en-
deavoured to embrace in the following account.
In the first place the frontal, at its entrance
into the orbit, anastomoses with the fourth
nerve. Next it gives off, some time after its
entrance and previous to its division, a long and
slender branch, which runs forward and inward
toward the trochlea of the superior oblique.
Then it divides into two branches, a larger
one, the continuation of the nerve, which
escapes through the superciliary foramen, and
a smaller, the supra-trochlear or internal
frontal. The latter passes forward and at the
same time inward toward the trochlea of the
oblique muscle, escapes from the orbit internal
to the continued trunk of the frontal nerve,
and ascending upon the forehead beneath the
corrugator supercilii, orbicularis, and frontalis
muscles, it has received the name of internal
frontal, in contradistinction to the continued
trunk, which is at the same time called external
frontal. The point at which the frontal divides
is variable; for the most part the division takes
place about midway in the orbit. In some
instances it occurs before the nerve has reached
that point, and in others, again, not until it
has approached nearer to the anterior margin of
the orbit. The distance of the division from
the margin of the orbit appears to modify the
course of the internal branch : when it is far
back, the nerve escapes from the orbit above
the trochlea, and hence the name supra-tro-
chlear, given to it by Meckel ; and when near the
margin it escapes external to the trochlea, be-
tween it and the superciliary foramen ; while in
the latter case a branch of the nerve is transmitted
above the trochlea, in the usual course of the
nerve itself. Nor is the size of the two branches
into which the frontal divides equal or uni-
form ; for the most part the external branch is
the larger, but in some instances the two are
of equal size. In its course forward the supra-

trochlear nerve gives off first, occasionally a
delicate branch, which frequently arises from
the frontal itself prior to its division, the course
and destination of which have been already
described. Next it gives off, in some instances
before, in others not till after it has escaped
from the orbit, a branch which passes inward
toward the internal canthus, and, uniting with
either the infra-trochlear itself or a branch of
it, concurs in forming a small plexus, from
which filaments are distributed to the structures
of the upper eyelid, toward its internal part,
and to the eyebrow. Having escaped from
the orbit, the supra-trochlear nerve divides into
two sets of branches, denominated pulpcbral
and frontal ; the first descend into the superior
eyelid, and are distributed to the structures of
that part ; the filaments communicating exter-
nally with those of the frontal, and internally
with those of the infra-trochlear. The frontal
branches ascend round the superciliary arch,
beneath the orbicularis palpebrarum and the
corrugator supercilii muscles, upon the fore-
head, and these are disposed of in a manner
similar to that in which the branches of the
proper or external frontal are. Some are dis-
tributed to the orbicularis, corrugator, and fron-
talis muscles; other, long branches, ascend
beneath the frontalis, traverse it, and become
subcutaneous, and are distributed to the inte-
guments of the scalp upon the forehead. Of
these the external unites with the internal
branch of the external frontal, and forms with
it a common branch, which has the same
destination as the others.

The external larger branch of the frontal,
called, in contrast with the last, the external
frontal nerve, also divides into two sets of
branches, palpebral and frontal.

The nerve in some instances emerges from
the orbit a single trunk, in others it divides be-
fore it escapes from that region, for the most
part into two branches, which are transmitted
sometimes through the same, at others through
distinct apertures, and from which the several
ramifications arise, they themselves becoming
ultimately the long frontal branches.

Immediately after their escape the frontal
branches give off externally slender filaments,
which run outward toward the external can-
thus, one beneath the eyebrow, through the
upper eyelid, and one or more through the
brow itself; these ramify as they proceed, sup-
ply the lid and brow at their outer part, and
anastomose with filaments of the portio dura,
and of the superficial temporal nerve.

The frontal branches are arranged into super-
ficial and deep ; those epithets have been diffe-
rently applied by different writers ; thus those
which the elder Meckel terms the superficial,
Boyer and Cloquet denominate the deep
branches ; nor is this to be wondered at, inas-
much as both sets become ultimately superficial;
it were better, perhaps, to arrange them into
short and long branches. The short branches
are distributed to the orbicularis muscle, the
corrugator, and the frontalis, and having sup-
plied those muscles, they or others of them be-
come subcutaneous, and terminate in the inte-

FIFTH PAIR OF NERVES.

281

guments of the eyebrow and forehead : one
of these branches, as described by Meckel,
runs outward, through the orbicularis, toward
the external canthus, and establishes anasto-
moses with filaments of the facial portio dura
nerve. The long branches are two, an external
and an internal ; of those the external is, for
the most part, the larger ; they ascend beneath
the frontalis and the frontal aponeurosis, the
former inclining outward, the latter inward, as
they ascend ; they distribute in their course
ramifications to the muscle, and to the deeper
structures of the scalp, as well as some-
times, according to Meckel, to the pericra-
nium, and traversing the frontal aponeurosis,
they become subcutaneous, and terminate in
the structure and integument of the scalp. The
external communicates with the superficial
temporal nerves ; the internal with the internal
frontal, the supra-trochlear. They are said both
to anastomose with the branches of the sub-
occipital nerve; but Meckel states that he
has pursued them until they have escaped
his sight, and yet he could not discover any
anastomoses between them and the branches of
that nerve.

2. The nasal nerve is in size the second
branch of the first division of the fifth, and arises
always separately from the original trunk. Its
course is inferior and internal to those of the
other two, and hence the nerve is called by
some the inferior, by others the internal branch.
It is distributed partly to the eye and its appen-
dages and partly to the nostril, arid hence it is
also called naso-ocular by Soemmerring. The
direction of its course is forward and very
much inward ; it passes through the foramen
lacerum into the orbit ; then traverses that re-
gion from without inward toward its internal
wall, and having reached it at the foramen or-
bitarium internum anterius, it escapes from the
orbit through that foramen, and passes into the
cranium ; it emerges into the cranium from
beneath the margin of the orbitar process of the
frontal bone, and crosses the cribriform plate of
the ethmoid obliquely forward and inward,
contained in a channel in the bone, and in-
vested by the dura mater, until it reaches the
crista galli ; it then descends from the cranium
into the nostril, through the cleft, which exists
at either side of the crista galli at the anterior
part of the cribriform plate, and having reached
the roof of the nostril, it divides into its final
branches.*

The nasal branch is concealed at its origin
by the frontal, which is situate external and
superior to it. Before its entrance into the orbit
it is placed by the outer side of and closely ap-
plied to the third nerve. In entering the orbit

* The nasal is usually described as terminating
by dividing within the orbit into two branches, the
ethmoidal or internal nasal, and the infra-trochlear or
external nasal : the author has preferred considering
the former as the continuation of the nerve, be-
cause in inferior animals both the nasal is the prin-
cipal portion of the first division of the fifth, or
alone constitutes it, and it is manifestly prolonged,
as such, into the nostril and the beak. See Com-
parative Distribution.

it passes between the two posterior attachments
of the external rectus muscle, in company with
the third and sixth nerves, external to the
former and between its two divisions, and
internal and somewhat superior to the latter.
In its course across the orbit the nasal nerve
passes above the optic nerve, immersed in fat,
and accompanied by the ophthalmic artery,
being at the same time beneath the levator
palpebrs, the superior oblique, and superior
rectus muscles, and in crossing the optic
nerve, it is placed between it and the last
mentioned muscle. Through the foramen or-
bitarium the nerve is accompanied by the an-
terior ethmoidal artery, and within the cra-
nium is situate beneath but not in contact
with the olfactory bulb, being separated from
it by the dura mater. The course of the nerve
from the orbit to the nostril is liable to be
modified by the developement of the frontal
sinuses ; when they are very large, and extend,
as they not unfrequently do, into the orbitar
processes of the frontal bone and the horizontal
plate of the ethmoid, the nerve may cross to
the side of the crista galli without entering the
cranium, being contained in a lamella of the
ethmoidal bone. The nasal branch, before
entering the orbit, receives, according to Bock,
J. F. Meckel, and Cloquet, a filament from
the sympathetic. The branches which the nasal
gives off, are the lenticular, the ciliary, the
infra-trochlear, and the nasal.

The lenticular branch is given off as the nasal
enters the orbit, and on the outer side of the
optic nerve ; it is a delicate branch, about half
an inch long; it first anastomoses with the supe-
rior division of the third nerve ; then runs for-
ward along the outer side of the optic nerve,
and terminates by joining the superior and pos-
terior part of the lenticular ganglion. Accord-
ing to Bock and Meckel junior, it occasionally
gives off a ciliary nerve, and according to
Meckel senior it is, in rare instances, derived
from the third nerve. To the latter statement,
however, the author hesitates to assent : it ap-
pears to him, that it should rather be said in
such cases to be wanting.

The ophthalmic, lenticular or ciliary ganglion,
according to Cloquet, is of an oblong form —
its greater length from behind forward; it is
one of the smallest ganglia of the body,
being, however, variable in size ; its colour is
reddish, at times white; it exists constantly in
the human subject : it is situate between the
external rectus muscle and the optic nerve, laid
against the outer side of the nerve, at a little
distance from its entrance into the orbit ; its
external surface convex, corresponding to the
muscle ; its internal, concave, to the nerve ; to
its superior posterior angle is attached the len-
ticular twig of the nasal branch of the first
division of the fifth ; this filament constituting
its long root ; to its inferior posterior angle a
filament from the inferior division of the third
nerve is attached, constituting its short root.
To the posterior part of the ganglion are also
attached two filaments derived, one from the
cavernous ganglion or the carotid plexus ; the
other, the constant existence of which has not

282

FIFTH PAIR OF NERVES.

been yet established, from the spheno-palatine
ganglion.

The ganglion gives off from its anterior ex-
tremity a considerable number of very delicate
filaments, denominated from their distribution
ciliary : they amount to from twelve to sixteen ;
are reddish and tortuous; and run forward
along the optic nerve to the back of the eye,
which they enter at a short distance from the
nerve. They are distinguished into two fasci-
culi, superior and inferior ; which are attached,
one to the superior anterior, the other to the
inferior anterior angles of the ganglion : the
former is the smaller ; contains at first but three
filaments, which, as they proceed, divide so as
to produce six, and run parallel to each other
above the optic nerve : the second fasciculus is
situate on the outside of and beneath the optic
nerve, and contains from six to ten filaments col-
lected at their origin into six branches: they pass
beneath the nerve and incline inward, so as
to gain, some of them, its inner side : one of
them runs outward and joins one of the ciliary
branches of the nasal nerve. The ciliary nerves
all penetrate the sclerotic coat of the eye sepa-
rately and obliquely ; then run forward between
the sclerotic and choroid coats, without giving
filaments to either, lodged in channels upon
the inner surface of the former: as they ap-
proach the ciliary circle they divide, each into
two or three filaments, which enter the circle
and are lost in it : some of them pierce the
choroid at the anterior part of the eye, and go
to the ciliary processes.

The ciliary branches are two or three in
number ; they are very delicate, and are given
off, while the nasal is crossing the optic nerve ;
they run forward along the optic, imbedded in
fat, penetrate the sclerotic coat of the eye pos-
teriorly, and then continue forward between
the sclerotic and choroid coats, in like manner
as the other ciliary nerves, to the ciliary circle.

The infra-trochlear branch, so called by the
elder Meckel, because it escapes from the
orbit beneath the trochlea of the oblique mus-
cle, is also called external nasal. It is given
off when the nasal has reached the inner wall
of the orbit, and as it is about to enter the fora-
men orbitarium ; it is a branch comparatively
considerable, at times longer, at others smaller
decidedly than the continuation of the nasal ;
it runs directly forward along the inner wall,
beneath the superior oblique muscle, toward
its trochlea, and having reached that, escapes
from the orbit beneath it. It then divides, in
the internal can thus of the eye, into two
branches, a superior and an inferior.

The infra-trochlear, while within the orbit,
gives off occasionally, soon after its origin,
a small branch, which returns and joins the
nasal before it enters the foramen orbitarium ;*
also a delicate branch, which joins a corre-
sponding branch given off either by the supra-
trochlear or the frontal. The distribution of the
nerve resulting from their junction has been
already described under the frontal nerve. Of
its ultimate branches, the superior joins and

forms a plexus with a branch of the supra-ti'o-
chlear nerve, already described, given off either
immediately before or after that nerve has
escaped from the orbit. From the junction of
the two, numerous delicate ramifications are
distributed to the upper eyelid and to the eye-
brow. The inferiorgives off several ramifications,
which are distributed to the origin of the cor-
rugator, the orbicularis, and the pyramidalis
nasi muscles ; to the conjunctiva, at the inter-
nal canthus ; the carunculalachrymalis and the
lachrymal sac. Of those ramifications, one de-
scends before the tendon of the orbicularis, and
communicates with a branch of the portio
dura: another communicates with a branch of
the infra-orbital ; but the latter anastomosis is
uncertain.*

The nasal nerve having entered the nostril di-
vides at the roof of the cavity into two branches,
an external and an internal: of these the former
descends behind the nasal process of the frontal
and the corresponding nasal bones, contained
in the groove or canal observable upon their
posterior surface. It escapes from beneath
them at their inferior margin, emerging between
it and the lateral cartilage of the nose, and then
descends along the corresponding ala, superfi-
cial to the cartilage, and covered by the mus-
cles of the ala, toward the tip : as it approaches
the tip, it divides into two filaments, one of
which is distributed to that part, and the other
to the ala. During its descent along the side
of the nose it also gives off some delicate fila-
ments, and anastomoses with the ramifications
of the nasal branches of the infra-orbital nerve
and with the portio dura. It is called by
Chaussier the naso-lobar : it is also generally
known as the nerve of Cotunnius. The second
branch, as it proceeds, divides presently into
two, of which one attaches itself to the septum,
and descends, between the pituitary membrane
and the periosteum, parallel and near to its an-
terior margin, as the naso-palatine of Scarpa
does to its posterior : as it proceeds, it furnishes
ramifications to the membrane of the septum.
The second attaches itself to the outer wall of
the nostril, and descends, in like manner be-
tween the mucous membrane and the perios-
teum, along its anterior part, in front of the
middle turbinate bone, until it reaches the an-
terior extremity of the inferior one : it then
breaks up into branches, of which some are
distributed to the convex surface of the latter
bone in front, and others beneath it to the an-
terior part of the inferior meatus. The distri-
bution of the branch is very happily represented
in Arnold's Icones.

The nasal nerve is described as giving also,
in some instances, but not uniformly, a branch
to the membrane of the superior turbinate
bone, at the superior part of the nostril.

3. The third branch of the first division of the
fifth is the lachrymal: it has been so called by
Winslow from its distribution to the lachrymal
gland : it is the smallest of the three branches :
its course is external to that of the others, and
hence it is also called the external branch. It

* J. F. Mcckcl.

* The elder Meckel.

FIFTH PAIR OF NERVES.

283

• arises, for the most part, from the ophthalmic
at the same time with its other branches ;
J. F. Meckel asserts that it arises more fre-
quently from a trunk common to rt and the
frontal ; but the contrary is maintained by
the elder Meckel ; he, however, states that it
arises frequently by two roots, one from the
ophthalmic, and a second from the frontal, and
once he has seen it derive a root from the tem-
poro-malar branch of the superior maxillary
nerve.* When it arises from the ophthalmic, it
is at its origin, inferior to the frontal, and exter-
nal to the nasal. Its course is forward and
outward at a very acute angle with the frontal ;
it enters the orbit through the foramen lacerum,
and from its origin until its entrance it is con-
tained in the dura mater lining the inner side
of the middle fossa of the base of the cranium,
beneath the lesser wing of the sphenoid bone :
in entering it passes above the origins of the
external rectus muscle, between it and the pe-
riosteum, and pursues its course along the
outer wall of the orbit, external to the superior
rectus and superior to the external, until it
reaches the lachrymal gland : it then passes
between the gland and the eyeball, and then
divides into branches. It is accompanied
through its course by the lachrymal artery.
The branches into which it divides are, for the
most part, three ; they enter the gland on its
ocular surface, traverse it and again escape
from it on its external aspect ; in their course
through the gland they divide and commu-
nicate with each other, and thus form within
it a plexus, from which numerous ramifications
are distributed to its substance. After having
supplied the gland the branches of the lachry-
mal emerge from it, and pursue two destina-
tions : one of them, which is for the most part
the first branch of the nerve, and is frequently
given off before it has reached the gland, de-
scends backward toward the spheno-maxillary
cleft, and joins the temporal branch of the
temporo-malar branch of the second division of
the fifth. In its course this branch passes first
between the external rectus muscle and the
outer wall of the orbit, then becomes attached
to the wall, and is either simply inclosed in the
periosteum, or contained in a groove or canal
m the orbitar process of the malar, or some-
times of the sphenoid bone; in this canal it meets
the branch of the temporo-malar, and from the
junction of the two results a filament, the des-
tination of which will be described under that
of the temporo-malar. This branch of the
lachrymal nerve is called the posterior or sphe-
no-majcillary : it might from its destination be
appropriately termed temporal: it frequently
gives off in its descent a filament, which passes
forward, escapes from the orbit beneath the ex-
ternal canthus, and is distributed as the other
branches of the lachrymal are. The remaining
branches of the lachrymal escape from the
orbit into the upper eyelid, beneath the exter-

* [According to Cruveilhier the lachrymal nerve
very often arises by two filaments, one from the
ophthalmic, the other from the fourth nerve, and
Swan describes this as the normal condition. —
Cruveilhier, Anat. Deter, t. iv. p. 911.— ED.]

nal part of the superciliary arch. They give
off numerous filaments, which are distributed
to the structures of the lid, the conjunctiva, the
orbicular muscle, and the integument : the ex-
ternal of them, which are the largest, not only
supply brandies to the upper, but descend be-
hind the external commissure of the lids into
the lower one, which they supply at its outer
part; they are also distributed to the superfi-
cial parts on the malar region. They anasto-
mose with the frontal nerve, the superficial
temporal, the facial, the temporo-malar, and
the infra-orbital nerves.

The second division of the fifth. — This has
been called also by Winslow, in consequence
of its distribution, the superior maxillary nerve.
It is the second trunk connected with the
Gasserian ganglion, and is intermediate to the
others, both in size and situation ; larger than
the first, and placed beneath and external to it;
smaller than the third, and situate internal,
superior and anterior to it ; it is attached to the
middle of the anterior convex margin of the
ganglion; at first it is flattened, wide, and of a
cineritious tint ; but, as it proceeds, it becomes
contracted in width, of a cylindrical form, and
presents a white colour. At leaving the gan-
glion it is joined by a filament of the sympa-
thetic. This has been seen by Munniks* and
Laumonier,f and is stated by Meckel junior,
on the authority of the latter. The communi-
cation between the sympathetic and the second
and third divisions is called in question by
Arnold.^ That with the third the author has
not yet made out, but that with the second he
has found satisfactorily established by a fila-
ment from the branch of the sympathetic which
joins the sixth nerve : this filament connects the
sixth to the second division of the fifth, and is
short, but grosser than those which join the first :
in consequence of the irregularity which pre-
vails in the arrangement of the sympathetic
system, the description here given may not
apply in other instances.

The course of the second division of the fifth
within the cranium is short; it is directed for-
ward, slightly outward and downward, toward
the superior maxillary or the foramen rotundum
of the sphenoid bone; having reached that
foramen it enters the canal, of which it is the
aperture, and escapes through it from the
cranium. While within the latter the nerve
is contained in a sheath of dura mater, and
rests in a shallow channel on the body of
the sphenoid bone, at its junction with the
great ala. From the cranium it enters the
spheno-maxillary fossa, and crosses that fossa
at its superior extremity, from behind forward,
inclining still downward and outward, though
but slightly ; its course across the fossa is also
very short, extended between the root of the
pterygoid process behind and the highest part
of the posterior wall of the maxillary antrum
before; having traversed the superior part of
the fossa it enters the infra-orbital canal, through

* De Orisrine nervi intercostalis.
t Roux, Journ. de Med. t. xciii.
t Journ. Cornp. t. xxiv.

284

FIFTH PAIR OF NERVES.

which it is transmitted, in company with the in-
fra-orbital artery, to the face. In the canal it is
situate in the floor of the orbit or the roof of the
antrum, separated from each cavity, more or
less perfectly, by a thin lamina of bone ; its
course within the canal is by much its longest
stage; as the nerve approaches the anterior
extremity of the canal, it inclines inward, and
thus its course is rendered a curve, convex
outward. In this respect, however, it pre-
sents varieties, dependant upon the transverse
dimensions of the face, which being great,
the course of the nerve is more curved and
vice versa, it being sometimes nearly straight.
From the time that the nerve enters the canal,
it has been called infra-orbital; but, inasmuch
as that part of it is manifestly but the con-
tinuation of the trunk, and names are already
rather too numerous than otherwise, it would
be better if that one were discarded. From
the infra-orbital canal the nerve escapes through
its anterior aperture into the face ; that aperture
corresponds, for the most part, to the point of
junction of the two external with the internal
third of the inferior margin of the orbit, and is
from a quarter to half an inch below it; its
situation, however, is not uniform; in some
skeletons it will be found to correspond nearly
to the middle of the margin, and this circum-
stance is worthy of attention, in consequence
of its relation to the operation for the division
of the nerve.

At its escape from the canal the nerve is
concealed by the lower margin of the orbicu-
laris palpebrarum and by the levator labii supe-
rioris muscle, beneath which it is placed, and
it is above the upper extremity of the origin of
the levator anguli oris : immediately after its
escape it separates into a number of branches,
which go off in different directions to their
several destinations, but principally downward.

The branches which the second division
gives off are the temporo-malar, the spheno-
palatine, the posterior superior dental, the an-
terior superior dental, and the facial branches.
While within the cranium the nerve gives off
no branch.

1. The first branch given off by the second
division, the temporo-malar, has been called
cutaneous malar by the elder Meckel ; it has
been also called orbitar, but without good
reason ; the name temporo-malar fully expresses
its distribution. This branch is given off by
the nerve, either while yet within the canal,
through which it escapes from the cranium, or
after it has entered the spheno-maxillary fossa ;
it is one of its smallest branches ; it passes for-
ward through the fossa, toward the spheno-
maxillary cleft, enters the orbit through the
cleft, and then pursues its course forward and
outward, along the floor of that region, beneath
the inferior rectus muscle, and about the mid-
dle of it divides into two branches ; an exter-
nal, the temporal, and an anterior, the malar.

Before entering the orbit it sometimes gives
off a small branch, which enters that cavity
through the periosteum of the posterior part of
the orbitar process of the sphenoid bone, and
joins the lachrymal branch of the first division,

presenting one of the instances of a second root
to that branch, as described by the elder Meckel.

The external temporal branch passes toward
the outer wall of the orbit, ascends between it
and the external rectus muscle ; then becomes
attached to the wall, and continues its course
either through the periosteum, or in a groove,
or at times through a canal in the orbitar pro-
cess of the malar, or occasionally of the sphe-
noid bone ; here it is joined by the posterior
temporal branch of the lachrymal nerve, the
third branch of the first division : the conjoined
branch is then transmitted into the temporal
fossa, through an aperture on the temporal sur-
face of the orbitar process of the malar bone ;
there it is joined by a small branch of the an-
terior deep temporal branch of the inferior
maxillary or third division of the fifth, and
plunging among the fibres of the temporal
muscle, it is distributed to them in common
with the filaments of the deep temporal ; a
filament or filaments of it gain the superficial
surface of the muscle, perforate its aponeurosia,
become subcutaneous, and are distributed su«-
perficially upon the temple, communicating
with filaments of the portio dura, and of the
superficial temporal branch of the third divi-
sion. The temporal branch of the temporo-
malar is sometimes double, or divides into two,
one communicating with the branch of the
lachrymal, the other transmitted to the temple.

The malar branch pursues the course of the
original nerve, until it has reached nearly to
the anterior margin of the orbit, at its inferior
external angle ; then it enters, either single or
divided into two, the corresponding canal or
canals, by which the malar bone is perforated,
and through them is transmitted outward and
forward to the malar region of the face. Its
ramifications are distributed to the inferior ex-
ternal part of the orbicularis palpebrarum, and
to the integuments of the malar region ; they
communicate with those of the portio dura, of
the superficial temporal and lachrymal nerves,
and of the palpebral branches of the second
division. Before reaching the malar canals,
the malar branch frequently gives off one or
more filaments, which ascend to the lachrymal
gland, unite with those of the lachrymal nerve,,
and follow a similar distribution.

2. The branches, which are given off next by
the second division of the fifth, are those by
which the nerve is connected to the spheno-
palatine ganglion ; they are hence denominated
the spheno-palatine ; the ramifications derived
from them, or from the ganglion with which
they are connected, are distributed to the nos-
tril and the palate, and they may hence with
more propriety be termed the naso-palatine,
an appellation which is the more appropriate,
since it is already applied to the corresponding
branch of the second division of the fifth in
other animals. It is at the same time to be
borne in mind that a difficulty has been created
in this matter by the application of the epithet
in question to certain secondary branches, to be
mentioned by and-by ; but the latter use of the
term oupht to be discarded. They are irregular
in number, there being sometimes but one, a-t

FIFTH PAIR OF NERVES.

285

others ivr o or three : they are short and of con-
siderable size, and arise from the inferior side
of the nerve, immediately after it has entered
the spheno-maxillary fossa ; they descend from
it, almost perpendicularly, into the fossa, pos-
terior to the internal maxillary artery, and im-
mersed in fat, and after a very short course
they are connected to the ganglion, from which
they may seem to ascend to the nerve. They
are thus described by Cloquet, but this view is
not sanctioned either by comparative anatomy,
or by the result of experiments, both which
prove that they are to be considered branches
of the nerve, with which the ganglion is con-
nected.

The ganglion has been first described by
the elder Meckel,* and hence has also received
the title of Meckel's ganglion ; it is very small,
of a grey colour, and firm consistence ; its
shape is triangular or cordiform, one surface
directed outward, the other inward; it is situate
immediately external to the spheno-palatine
foramen, its internal surface, which is flat, cor-
responding to the foramen, its external, which
is convex, to the zygomatic fossa. It is subject
to variety ; in some instances it is wanting,
and then the spheno-palatine nerve gives off
those branches which otherwise arise from the
ganglion : in other rare cases, according to
Meckel, the two principal branches, which
arise from the ganglion when present, or
from the spheno-palatine when single, viz. the
Vidian and the palatine, proceed separately from
the trunk of the second division of the fifth ; in
others again the author has observed a cineri-
tious soft enlargement upon the Vidian nerve
at its junction with the spheno-palatine, but
not involving that nerve or the branches pro-
ceeding from it ; and this, it is worth remark-
ing, is precisely the disposition of the ganglion
in the dog and some other animals. Different
views have been taken of the nature and rela-
tions of this ganglion: the Meckels, by the
elder of whom it was discovered, Bichat, Boyer,
and others, have regarded it as belonging pro-
perly to the fifth nerve, and formed by the
branches which have been mentioned : Cloquet,
on the other hand, considers and describes it
as a pail of the ganglionic or sympathetic
system, and all the nerves connected with it,
as well the original spheno-palatine branches
as the others, to be branches from it : Cruveil-
hier again, while he admits the existence of
ganglionic structure, yet leaves it uncertain
whether he regards it as a sympathetic or a
cerebro-spinal ganglion, but he differs from
Cloquet in maintaining that " the nerves,"
which seem to arise from it, " are not detached
from the ganglion itself, and come directly
from the superior maxillary." The opinions of
Cloquet and Cruveilhier appear to the author
to be both, to a certain degree, well-founded.
The ganglion would seem not to be properly a
part of the fifth nerve, because, 1 . it is not, as
he believes, present in animals below the mam-
malia ; 2. it is not always present even in them,
and in neither case is the general distribution

* Mem. de 1'Acad. de Berlin, 1794.

of the part of the fifth nerve, with which it is
connected, influenced by its absence ; 3. it is
manifestly different in its characters from the
fifth nerve and from the branches of the nerve
to which it is attached, nor does it resemble
the cerebro-spinal ganglia, the peculiar appear-
ance of these bodies, viz. white filaments enter-
ing and emerging, their continuity being appa-
rently interrupted by an interposed mass of
cineritious matter, not being observable; while,
on the other hand, it resembles the ganglia of
the sympathetic, and is actually connected with
that nerve by a branch having precisely the
same qualities with those which proceed from
it, viz. by the inferior branch of the Vidian
nerve: for those reasons the author would
adopt the opinion of Cloquet, that the ganglion
is properly a part of the ganglionic system, and
that it is only accessory to the fifth nerve. On
the other hand, it appears to him that Cloquet
is mistaken in considering the ganglion as the
source of all the nervous filaments connected
with it, and more particularly of the spheno-
palatine branches of the second division of the
fifth, to which in man the ganglion is attached,
for, as has been already stated, the general dis-
tribution and existence of these branches are
not at all influenced by the absence of the gan-
glion, and when present it allows in general, as
Cruveilhier has observed, the nerves to be fol-
lowed up and down from the swelling, and
lastly, any obscurity existing with regard to
this point in the human subject will be at once
removed by reference to the disposition of the
ganglion in other animals, in none of which
that the author has examined does it involve
the nerve, but is merely connected to it either
by filaments or by one extremity, the continuity
of the nerve being altogether uninterrupted,
and a marked contrast being to be observed
between the characters of the two parts : thus
in the dog, the ganglion is an oblong dark-
grey swelling, with the posterior extremity of
which the Vidian nerve is united, while its an-
terior is attached to the naso-palatine nerve.
The author, therefore, concurs in the opinion of
Cruveilhier, so far as to regard the nerves con-
nected with the ganglion, for the greater part,
as branches of the fifth nerve and not of the
ganglion; but he would exclude from this view
the Vidian nerve, or at least its carotidean
branch, which appears to him to belong to the
sympathetic system. (See posterior branch of
ganglion.)

The disposition of this ganglion throughout
the animal series is an object of interest. The
author cannot assert its existence in the mam-
malia universally, but from indirect considera-
tions it appears to him likely that it does exist,
generally at least, in animals of that class. Jt
is asserted in the work* of Desmoulins and
Majendie on the Anatomy of the Nervous Sys-
tem in vertebrate Animals, that " there does
not exist any trace of it in cats, dogs, the rumi-
nantia, the rodentia, the horse, &c. ;" and it is
reasonable to infer that they had found it in
others. Now their statement with regard to

* Tom. ii. p. 396.

286

FIFTH PAIR OF NERVES.

its absence is, in the majority of the instances
which they have selected, positively incorrect,
for the author has ascertained its existence
most satisfactorily in the dog, the horse, the
cat, the cow, and the rabbit. Nor is any ex-
ception to its existence mentioned by Cuvier,
and hence he thinks it likely that it does exist
generally, if not universally, throughout the
class. It is not however similarly disposed in
all ; in some it is connected with the primitive
naso-palatine nerve; in others with its nasal;
and in others again with its palatine division :
in some it gives off few filaments ; in others,
the horse, e. g. they are numerous beyond de-
scription. The ganglion does not appear to
exist in the inferior classes.

From the spheno-palatine ganglion or nerve,
according to the view of their source adopted,
there is given off a considerable number of
branches, which run in different directions and
have different destinations : they have been
distinguished into four sets, viz. superior, infe-
rior, internal, and posterior. The superior
branches are very delicate and, in some in-
stances at least, numerous. Among them are
described and represented by Arnold two long
slender filaments, which join the optic : ano-
ther is also mentioned by him to be sometimes
found connected with the ophthalmic ganglion.
The discovery of this connection between the
two ganglia is due to Tiedemann, who found,
upon the left side of a man, an anastomosis
between them, established by a filament, of
tolerable size, which, arising from the inner face
of the spheno-palatine, entered the orbit and
passing above the inferior branch of the motor-
oculi nerve, where it gives off the short root,
went in company with the last to gain the in-
ferior and posterior part of the ophthalmic gan-
glion ;* and beside those there may be found,
in favourable subjects, others, which seem
destined to the posterior ethmoidal cells. The
inferior branch is the largest given off by the
ganglion; it is distributed principally to the
palate, and hence is called " the palatine ;"
but it supplies the nostril also in part, and
hence it has been suggested by J. F. Meckel,
that it might be appropriately called the
" naso-palatine:" this appellation has, however,
been applied by Scarpa to one of the internal
branches, and it has been already explained
that it belongs more properly to the original
branch before its junction with the ganglion.
The palatine nerve descends from the ganglion
into the spheno-maxillary fossa, posterior to
the internal maxillary artery and toward the
ptery go- palatine canals, and after a short course
divides into three branches ; an anterior, larger
one, denominated " the great palatine," and
two posterior smaller branches, " the lesser
palatine nerves."

These branches continue to descend in com-
pany until they reach the superior apertures of
the canals ; they then enter the canals and are
transmitted downward through them to the
palate and fauces. The great palatine descends
through the anterior pterygo-palatine canal,

* Journal Cpmpl. vol. xxiv. Arnold.

in company with a branch of the palatine
artery, at the same time inclining forward :
during its descent it gives off, in some in-
stances before, in others after it has entered
the canal, either one or two filaments, which
descend inward, pass through the nasal process
of the palate bone, and enter the nostril at the
back part of the middle meatus, between the
posterior extremities of the middle and in-
ferior turbinate bones : one of them is dis-
tributed to the membrane of the middle bone
and of the middle meatus ; the other to that
of the convex surface of the inferior bone :
when a single branch arises from the palatine
it divides into two, which follow a similar*
distribution; these branches are denominated
by the elder Meckel inferior nasal nerves in con-
tradistinction to the superior nasal, to be de-
scribed, given off by the ganglion and by the
Vidian nerve. Another filament is described
by Cloquet arising from the palatine shortly
before it escapes from the canal, entering the
nostril through the perpendicular plate of the
palate bone, running along the margin of the
inferior turbinate bone, and lost upon the
ascending process of the superior maxillary
bone, often also contained in an osseous canal.

The great palatine nerve, then, for the most
part divides into three branches, of which one,
the smallest, descends through an accessory
canal, in the pterygoid process of the palate-
bone, leading from the anterior, and escapes
from it inferiorly into the soft palate in which
it is consumed.

The other two escape from the pterygo-
palatine canal, through the posterior palatine
foramen, into the palate : at emerging from
the foramen they are situate very far back,
in the posterior angle of the hard palate on
either side, and behind the last molar tooth
of the upper jaw; they are immediately super-
ficial to the periosteum, and above the other
structures of the palate ; they are lodged,
along with the branches of the accompanying
artery, in channels upon the inferior surface
of the palatine processes of the palate and the
superior maxillary bones; they pass forward,
one along the alveolar arch, the other toward
the middle line of the palate, and subdivide,
each, into several branches, which are dis-
tributed to the structures of the hard palate,
the mucous glands and membrane, and to the
gums, and communicate in front with branches
of the naso-palatine ganglion.

In some instances the palatine nerve does
not divide into those ultimate branches until
after it has escaped from the palatine canal ;
but their disposition in such cases is in other
respects the same.

The lesser palatine nerves are posterior to
the greater; they are transmitted also through
the pterygo-palatine canals, the first through the
posterior, the second through the external.

The first, the larger of the two, and called
middle palatine nerve, escapes from the canal
inferiorly in front of the hamular process of the
sphenoid bone, and divides into filaments',
which are distributed to the soft palate and its
muscles.

FIFTH PAIR OF NERVES.

287

The second, the posterior, little palatine
nerve, descends at first between the external
pterygoid muscle and the posterior wall of the
antrum, then enters the canal, and escapes
inferiorly external to the former; it divides
into two filaments, one of which is distributed
to the soft palate, the other to the tonsils and
arches of the palate.

Those branches are accompanied by minute
branches of the palatine artery.

The internal branches vary in number from
three to five; they arise from the inner surface
of the ganglion, run directly inward, posterior
to the nasal branch of the internal maxillary
artery, toward the spheno-palatine foramen,
which they immediately reach ; pass through
the foramen, perforating the structure by which
it is closed, and enter the nostril, and thus
attach the ganglion closely to the foramen :
at their entrance into the nostril they are situate
before and beneath the anterior wall of the
sphenoidal sinus, at the back part of the su-
perior meatus, and immediately above the
posterior extremity of the middle turbinate
bone.

They are distinguishable, according to the
majority of descriptions, into two sets; one
destined to the outer wall of the nostril and
denominated by Meckel anterior superior
nasal, in contradistinction to branches of
the Vidian nerve, which he has designated
" posterior superior nasal," and another con-
nected with the septum. A third destination
has been assigned to them by Arnold, accord-
ing to whom a branch derived either from one
of the nerves of the septum, or originally from
the ganglion itself, is distributed to the supe-
rior part of the pharynx, corresponding to the
pharyngeal branch of Bock.

The anterior superior nasal branches are
either one or two in number ; when but one,
it divides into branches corresponding to the
two ; it is so expressed in Arnold's fifth plate ;
one of the two divides into filaments, which
are distributed to the posterior ethmoidal cells,
to the posterior part of the superior turbinate
bone, arid to the superior meatus, to the mem-
brane of those parts. The second distributes
its filaments to the convex surface of the mid-
dle turbinate bone ; according to Cloquet they
in part perforate the bone, and thus gain its
concave surface : they all run between the
periosteum and the mucous membrane, and
are distributed finally to the latter.

The branches connected with the septum are
two, a short and a long one ; they both pass
across the anterior wall of the sphenoidal
sinus from without inward, and thus reach
the posterior part of the septum nasi, become
attached to it, and changing their direction
descend forward along it, between the perios-
teum and mucous membrane.

The short, lesser, branch is situate very near
to the posterior margin of the septum, to
which it is parallel in its course, and distri-
butes its filaments to the membrane of the
posterior part of it: one of them is repre-
sented by Arnold as constituting the phar
geal branch.

The long branch descends to the superior
aperture of the anterior palatine canal, enters
the canal, and in it the nerves of the two sides
are united to a small ganglion denominated
the naso-palatine ; from it filaments descend
to the anterior part of the palate, in which
they are distributed and communicate with
filaments of the palatine nerves. Each nerve,
during its course along the septum, is situate
nearer to its position inferior than to its supe-
rior anterior margins : it is said not to give
any filaments during its descent, but this is
incorrect, as is well represented by Arnold ;
those, which it gives off, are distributed to the
membrane of the septum about its middle;
at times also it divides into two filaments,
which are afterwards reunited. Each nerve is
received inferiorly in a separate canal, which
inclining inward is soon united to the other
in the palatine, and in it the nerve or the
naso-palatine ganglion receives a filament of
communication from the anterior superior den-
tal branch of the second division of the fifth,
as described by Cloquet.

This branch has been particularly described,
first by Scarpa,* and by him denominated
the naso-palutine ; it has been also described
by J. Hunter,t between whom and Scarpa
appears to lie the merit of having first ob-
served it ; it is also known as " the nerve of
the septum," but the latter appellation is ma-
nifestly incorrect ; nor is the former free from
objection, inasmuch as the same title has been
applied, and with reason, in the inferior Mam-
malia, to the original branch given off by the
second division of the fifth for the supply of
the nostril and palate, with which the spheno-
palatine ganglion is connected, and which in
man has received the name of spheno-palatine
branch. The branch of the ganglion in ques-
tion is called by some the nerve of Cotunnius,
but incorrectly ; having been first described by
Scarpa, it cannot with justice be attributed to
the former.

The posterior branch of the ganglion is de-
scribed and represented by the majority of
authorities as arising single and in its course
dividing into two filaments; but Bock, J. F.
Meckel, and Hirzel state that the two fila-
ments at times are throughout distinct and
connected separately to the ganglion ; and
Arnold represents, in like manner, two fila-
ments arising from the ganglion, corresponding
to the two into which the single nerve divides.
The posterior branch arises from the back of
the ganglion, passes directly backward from it,
and is received immediately into the pterygoid
or Vidian canal, along with the corresponding
branch of the internal maxillary artery: it
is transmitted through the canal backward
and slightly outward, beneath the course of
the second division of the fifth itself, and
external to, or in many instances beneath the
sphenoidal sinus ; having traversed the canal,

* Annotations Academics, in which is also con^
tained a good representation of the nerve as a
single branch.

* Animal (Economy.

288

FIFTH PAIR OF NERVES.

it escapes from its posterior aperture into the
foramen lacerum anterius basis cranii : in this
it is contained in the fibrous structure by
which the foramen is closed, and is situate
at the outer side of and beneath the internal
carotid artery, as that vessel ascends, from
the aperture of its canal in the petrous bone,
into the cavernous sinus. Here also, or even
before it has escaped from the Vidian canal,
it receives, when single, a filament of com-
munication from the superior cervical ganglion
of the sympathetic: this filament had been
long regarded as arising from the posterior
branch itself, and — though at present gene-
rally* considered a branch from the sympa-
thetic— it has been for the most part described,
in systematic works, as such under the name
of the inferior, deep, sympathic, or carotidean
branch of the Vidian nerve. In its direction
it certainly resembles a branch of that nerve ;
but in that particular it is equally entitled to
be regarded one from the sympathetic to the
spheno-palatine ganglion, it being either from
before backward and from above downward,
or from behind forward and from below up-
ward. Further, in sensible qualities it strictly
resembles other branches of the latter nerve ;
it is, as has been stated, at times separate from
the proper Vidian, and connected directly with
the spheno-palatine ganglion ; and it is, in fact,
but one of the branches which ascend into the
cranium from the superior cervical ganglion
along the internal carotid artery, so that it
would be equally correct to describe that fila-
ment which is connected with the sixth nerve
as a branch of that nerve, as to style the fila-
ment in question a branch of the Vidian nerve.

The view of the nature of this filament here
advanced is, however, not universally admitted.
Cruveilhier objects to it because the cranial
branch of the Vidian nerve appears to him to
resemble in all respects the carotidean : this,
however, cannot be considered a valid objec-
tion, it can only prove that one branch may be
as much allied to the ganglionic system as the
other, but the validity of the assertion may be
questioned; however it may be in man, the
characters of the two branches in the larger
quadrupeds, the horse e. g. are sufficiently
distinct, the cranial branch being of a pure
white colour, and the carotidean having a gan-
glionic enlargement upon it at its junction with
the cranial.

While traversing the pterygoid canal, soon
after it has entered that canal, and in some cases
even before, the posterior branch of the gan-
glion gives off from its inner side two or three
filaments, denominated by the elder Meckel
posterior superior nasal : these enter the poste-
rior superior part of the nostril, in one case by
passing through the spheno-palatine foramen,
in the other by perforating the inner wall of
the pterygoid canal, and are distributed to the
posterior part of the lateral wall of the nostril,
to the root of the septum, to the sphenoidal
sinus and to the lateral wall of the pharynx
in the vicinity of the orifice of the Eustachian

* Bock, Cloquet, Hirzel, J. F. Meckel.

tube. These branches frequently arise from
the ganglion itself by a single filament, de-
nominated by Bock the pharyngeal nerve, and
represented by Arnold among the internal
branches of the ganglion : it divides into fila-
ments distributed to the several parts men-
tioned.

After the junction of the sympathetic fila-
ment, the posterior branch is continued through
the fibrous structure already mentioned, ex-
ternal to the internal carotid artery, and
thus enters the cranium. It then passes out-
ward, backward, and upward, upon the ante-
rior surface of the petrous bone, beneath
the third division of the fifth, very near
its attachment to the Gasserian ganglion,
and enclosed in the dura mater : it is at the
same time lodged in a channel upon the sur-
face of the bone. It is stated by Cloquet that
it here sends into the cavity of the tympanum
by two canals, the orifices of which are to be
seen in the channel one above the other, two
filaments of extreme delicacy, which go to
anastomose together upon the promontory, and
to communicate with a filament of the supe-
rior cervical ganglion, and with the glosso-
pharyngeal nerve. According to Hirzel,* this
connection between the superficial branch of
the Vidian and the tympanic branch of the
glosso-pharyngeal nerve on the nerve of Jacob-
son, takes place in the vicinity of the junction
of the former with the facial nerve. Accord-
ing to Arnold,f the superficial branch of the
Vidian nerve is, as proved by the researches of
others and his own, not simple, but composed
of two or of several filaments, and is accom-
panied by one or more very delicate filaments
from the carotid plexus. In one instance he
found the petrous nerve composed of four
filaments on the right, and three on the left.
The existence of several distinct filaments in
the Vidian nerve may be easily observed in the
larger animals. It pursues the course men-
tioned, until it has reached the hiatus Fallopii,
through which it is transmitted to the aqueduct
of Fallopius, where it meets and becomes in-
timately connected with the facial portio dura
nerve. At their junction the facial nerve pre-
sents a gangliform swelling, from which two
very delicate filaments proceed to the auditory
nerve. %

From the time that the posterior branch of
the ganglion enters the cranium until it has
joined the facial nerve, it is called the cranial
or superficial petrous branch of the Vidian
nerve ; by Arnold petrosus superficial major
in contradistinction to another nervous filament,
which connects his t otic' ganglion to the tym-
panic branch of the glosso-pharyngeal nerve ;
but the application of either of these epithets
would be rendered unnecessary by ceasing to
consider the filament by which the posterior
branch of the ganglion is connected to the
sympathetic, a branch of the former.

The posterior branch is also known by other

* Journ. Compl. t. xxii.
t Journ. Compl. t. xxiv.

$ Arnold. See lingual branch of third divisioa
and chorda tympani.

FIFTH PAIR OF NERVES.

289

names, viz. the recurrent, the pterygoid, the
Vidian, the anastomotic, or sy input hie.

3. The next branch or branches of the su-
perior maxillary nerve are the posterior supe-
rior dent ul. These arise from the nerve in
front of the internal maxillary artery, between
it and the back of the antrum, and are sepa-
rated from the artery by the spheno-palatine ;
they are very irregular as to their number and
precise place of origin ; at times there is but
one branch, at others there are two or three :
they are distributed to the buccinator muscle
and the mucous membrane of the posterior
lateral part of the mouth, to the roots of the
posterior teeth, the membrane of the maxil-
lary antrum, and the gum of the upper jaw.
When but one branch is present, its sub-
divisions supply the place of the others. It
descends into the fossa, behind the superior
maxillary bone, and before the internal maxil-
lary artery, and after a certain way divides
into two branches or sets of branches, posterior
and anterior.

The posterior consists of several long slen-
der filaments, which continue to descend im-
mersed in the fat of the zygomatic fossa, until
they reach the surface of the buccinator muscle;
they then in part are distributed to it, but in
greater number pass between the fibres of the
muscle and are lost in the mucous membrane
of the mouth.

The anterior branch descends for some time,
until it reaches the back of the maxilla ; it
then enters a canal in the bone, within which
it is transmitted forward through the wall of
the antrum ; after a short way it escapes from
the canal and continues its course forward
within the wall, between it and the lining
membrane, describing a curve convex down-
ward ; having reached the front of the antrum
it ascends and terminates by joining either the
anterior superior dental or a branch of that
nerve.

During its course around the antrum the
anterior branch of the nerve gives off down-
ward numerous delicate filaments, which de-
scend towrard the teeth, traverse the structure
of the alveolar arch, and in part are distributed
to the roots of the posterior superior teeth in
a manner analogous to that of the inferior
dental nerves : in part they escape inferiorly
from the alveolar arch between the sockets of
the teeth, and are consumed in the gums.
The nerve is also stated to give filaments to the
membrane of the maxillary antrum.

4. Shortly before its escape from the infra-
orbital canal, but at a distance somewhat
variable from it, the second division of the
fifth gives off its next regular branch, the
anterior superior dental : this descends, from
the infraorbital canal, through one of its own
name in the anterior wall of the antrum to-
ward the canine tooth ; it next runs inward
above the root of that tooth, and then again
descends through the perpendicular process
of the maxillary bone, until it reaches the floor
of the nostril, and is continued inward through
the horizontal process of the bone above the
roots of the incisor teeth.

VOL. ir.

While descending through the wall of the
antrum the anterior superior dental nerve
either is joined by the termination of the anterior
branch of the posterior dental, or it divides into
two, one of which inclines outward and joins
that branch, the other pursues the course of
the nerve. It supplies the anterior teeth of
the upper jaw in the same manner as the pos-
terior nerve does the posterior teeth ; it also
gives at its termination filaments to the mem-
brane of the nostril, and one to the naso-
palatine ganglion or nerve.

Besides the regular dental nerves, others at
times arise from the second division of the
fifth within the infraorbital canal, and take the
place of branches of the regular nerves.

5. The facial branches of the second division
of the fifth are from five to seven in number ;
they differ from each other in size, and branch
off in different directions; they are distin-
guished, according to the direction in which
they run and their destination, into three sets ;
a superior or palpebral, an inferior or labial,
and an internal or nasal.

For the most part there is but one superior
or palpebral branch, though sometimes there
are two. This branch is destined to supply the
lower eyelid, and is denominated the inferior
palpebral nerve ; it presents some variety in its
mode of origin and its course ; most frequently
it does not separate from the trunk till after the
latter has escaped from the infraorbital foramen;
but in some instances it does so within the in-
fraorbital canal, is transmitted through a dis-
tinct canal, and escapes into the face through a
separate foramen, situate internal to the infra-
orbital; it ascends inward toward the lower
lid, in front of the inferior margin of the orbit;
in its ascent it is situate beneath the orbicularis
palpebrarum, to which it gives filaments, which
after supplying the muscle become cutaneous,
and it is frequently contained in a superficial
groove on the superior maxilla ; having reached
the lid it divides into two branches, an external
and an internal. The external runs outward,
through the lid, toward the external angle,
supplies its structures on that side, and anasto-
moses with filaments of the portio dura, and of
the inferior palpebral branches of the lachrymal
nerve. The internal ascends in the course of the
original nerve toward the internal canthus of
the eye, gives a filament to the side of the nose,
which communicates with the naso-lobar branch
of the nasal nerve, supplies the lower lid at its
internal part, is also distributed to the carun-
cula and lachrymal sac, and anastomoses with
a filament of the inferior branch of the infra-
trochlear nerve described in the account of that
nerve. It sometimes anastomoses also with
the portio dura.

When there is a second palpebral branch, it
takes the place of the external branch of the
former, which in such case is denominated the
internal inferior palpebral, and the second the
external. It perforates the levator labii supe-
rioris muscle ; ascends toward the external
angle of the eye, beneath the orbicularis palpe-
brarum ; and, like the external branch of the
inferior palpebral, already described, supplies

290

FIFTH PAIR OF NERVES.

the structure of the lid, and anastomoses with
the portio dura, lachrymal, and malar nerves,
as also with the internal palpebral.

The descending or labial branches are the
largest and the most numerous ; for the most
part they are three, at times four. They de-
scend to the upper lip, one toward its middle,
the second toward its intermediate, and the
third toward its outer part, the commissure of
the lips, and are denominated internal, mid-
dle, and external; they are situate, all at first,
beneath the levator labii superioris, between it
and the levator anguli oris or canine muscle;
as they descend, they give filaments to these
muscles and to the parts superficial to them ;
and they pass to their several destinations, the
internal between the levator labii and the de-
pressor alae nasi ; the middle between the same
muscles ; and the external superficial to the
levator anguli, and uncovered by the levator
labii ; as they approach the lip they divide
each into branches, which are distributed to
the structures of the part at their several situa-
tions ; to the orbicularis oris, and the insertions
of the other muscles of the lip, to the integu-
ment of the lip, internal and external, and also
to the labial glands ; they all communicate to-
gether, and with branches of the portio dura ;
the external more particularly with the latter,
as also with the neighbouring branches of the
fifth ; the internal with the inferior nasal ; the
external with the inferior labial and buccal
nerves. In the infraorbital region, the branches
of the superior maxillary are crossed by and
interlaced with those of the portio dura; the
latter running from without inward, and for the
most part superficial to the former ; but also
beneath and among them, and even forming
loops about them ; while the former run from
above downward, and are principally deeply
seated. In consequence of this diversity in
their directions and the numerous anastomoses
which they hold with each other, the branches
of the two nerves form a very intricate mesh in
that region.

In some Carnivora filaments of the facial
branches of the fifth nerve have been traced
into the bulbs of the hairs of the whiskers and
the tufts with which they are furnished ; this
is remarkably so in the seal, as described by
Andral : they are strongly expressed by Rapp.*

The internal or nasal branches are, for the most
part, two ; they are termed superficial nasal by
the elder Meckel, and distinguished into supe-
rior and inferior; they pass, both, inward toward
the nose, beneath the levator labii superioris,
the inferior at the same time descending, and
having reached the side of the nostril they sub-
divide.

The superior is the smaller of the two, and
arises frequently from a branch common to it
and the internal inferior palpebral ; it divides
into three, of which the first, the uppermost, is
distributed to the origin of the levator labii
alaeque nasi, to the compressor naris, and to the
integuments on the dorsum of the nose; the

* Die Verrichtungen des flinftcn Hirnnerven-
paars.

second, the middle, to the compressor naris
and also to the integuments of the nostril, and
the third, the inferior, to the compressor naris,
to the depressor alae nasi, and to the integu-
ments of the ala.

The inferior superficial nasal, the larger of
the two, first gives occasionally a branch, which
ascends to the eyelid ; then communicates with
the superior, and having reached the ala of the
nose, it gives off numerous ramifications which
are distributed to the levator and depressor alae,
to the integuments of the inferior part of the
ala,' of the tip, and of the septum, and also to
the upper lip ; it communicates with the rami-
fications of the naso-lobar branch of the nasal
nerve, of the internal labial, and of the portio
dura.

The third division of theffth. — This trunk
has been denominated by Winslow, on account
of its general distribution, the inferior maxillary
nerve, and it is generally known by that appel-
lation ; yet it appears to the writer that it
would have been much better had that title
been applied only to that portion of the nerve
which enters the lower jaw. Such is the
opinion of the elder Meckel, who observes that
this use of the epithet leads to the inconveni-
ence that the branch alluded to and the trunk
of the nerve may be easily confounded. It is
much the largest of the three divisions, and
differs remarkably from the other two in its
composition ; they are both single, and derived
altogether from the Gasserian ganglion ; it on
the contrary is composed and made up of two
portions, one derived from the ganglion, the
other not connected with it ; the former is the
largest of the three trunks connected with the
ganglion ; it is attached to its posterior external
extremity ; at its attachment it is cineritious
and very wide, but as it proceeds it loses that
tint, and acquires a compressed cylindrical
form. It is situate external, posterior, and in-
ferior to the others, and its course within the
cranium is very short or none, for from the
ganglion it enters at once the inferior maxillary
or foramen ovale of the sphenoid bone, and
escapes from the cavity, passing downward, for-
ward, and outward, nearly at right angles with
the second division of the fifth. Before leaving
the cranium it is joined, as the first and second
divisions are, by a filament from the sympa-
thetic, according to Munniks, Laumonier, and
Bock.*

The second portion, of which the third
division is composed, is the lesser packet of
the fifth itself; this, it has been already stated,
does not join the ganglion, but passing out-
ward, beneath that body, is united to the former
portion posteriorly, in the foramen ovale ; it
forms, however, but a small proportion of the
nerve, that part which is attached to the gan-
glion exceeding it very much in size. At its
junction, it is placed posterior to the other,
but it immediately spreads out, and increases
very much in width, and at the same time is
lapped round the inner side of the ganglionic
portion so as to get before it, and to form the

* Op. cit. and Journ. Compl.

FIFTH PAIR OF NERVES.

291

anterior part of the nerve by the time it has
escaped from the cranium.

The third division of the fifth nerve, after its
escape from the cranium, is situate in the
superior, posterior, and internal part of the
zygomatic fossa ; it is placed immediately be-
hind the external pterygoid muscle, before and
somewhat internal to the styloid process of the
sphenoid bone, internal to and on a line with
the anterior margin of the temporo-maxillary
articulation, and external to the Eustachian
tube. So soon as the inferior maxillary nerve
has entered the fossa, it gives off, immediately
beneath the superior wall of that fossa, a set
of branches remarkable for their source and
destination ; they proceed from the front of the
nerve; their regular number is five, but they
present variety in this respect, being in some
instances not so many at their origin, in others
amounting to six ; they vary also in the mode
in which they arise; for the most part they
are given off separately and branch off, as
rays, from the nerve, but at times the nerve
divides into two branches, a smaller anterior
one, and a larger posterior ; in such case the
anterior divides immediately into the branches,
which otherwise arise from the nerve itself.
These branches are the masseteric, the deep
temporals, the buccal, and the pterygoid nerves,
and they are ranged in succession from behind
forward, and from without inward ; the first is
external and posterior; to it succeed the tempo-
rals, then the buccal, and lastly the pterygoid.

1 . The masseteric branch proceeds from the
anterior and outer part of the nerve; it passes out-
ward, nearly transversely, beneath the superior
wall of the temporal fossa, and in front of the
articular surface of the temporal bone ; it crosses
obliquely over the external pterygoid muscle,
at its outer extremity, between the muscle and
the wall of the fossa, and then inclines down-
ward through the sigmoid notch of the lower
jaw, in front of its neck, and of the insertion of
the external pterygoid muscle, and posterior to
the coronoid process and the tendon of the
temporal muscle. Having traversed the notch
it descends forward, external to the ramus of
the jaw, and passing between the two portions
of the masseter, divides into numerous ramifica-
tions, which are distributed altogether to that
muscle : while between the portions of the
masseter, it inclines from its posterior toward
its anterior margin, and its terminating filament
can be traced to the latter at the inferior part
of the muscle. This branch gives off, during
its course, some minor branches ; while in front
of the articulation of the jaw it gives one or
more filaments to the articulation ; in the next
place it gives a small branch to the posterior
part of the temporal muscle, and lastly it fre-
quently gives off the external or posterior deep
temporal nerve.

2. The deep temporal branches are two; they
are distinguished into posterior and anterior or
external and internal. The anterior is the
larger. They present varieties in their num-
ber and mode of origin ; at times there is but
one, at others there are three ; in some instances

they arise by a common origin ; in others, and
for the most part, separately, and in others
again the posterior or lesser branch is given off
either by the masseteric or the buccal nerve.
They both pass outward, in front of the tem-
poro-maxillary articulation, between the exter-
nal pterygoid muscle and the superior wall of
the zygomatic fossa; they then change their
direction and ascend in the temporal fossa, be-
tween the muscle and the surface of the fossa,
and divide into branches, which attach them-
selves to the temporal muscle, on its deep sur-
face, and are distributed, those of the posterior
to its posterior, and those of the anterior to its
middle and anterior parts. The two branches
frequently anastomose with each other as they
leave the zygomatic fossa. The anterior also
frequently communicates with or receives a
branch from the buccal nerve, and by one of
its anterior filaments it anastomoses with the
nerve resulting from the junction of the tempo-
ral branches of the lachrymal nerve and the
temporo-malar branch of the second division of
the fifth. This communication between the
three divisions of the fifth is however, accord-
ing to the elder Meek el, subject to variety; he
states that he has seen the communicating
branch of the anterior deep temporal at times
enter the orbit either through the malar bone,
or through the spheno-m axillary fissure, and
there unite with the conjoined branch of the
other two.

3. The buccal nerve is the largest and the
principal of these branches ; it arises from the
front of the inferior maxillary nerve, next in or-
der after the anterior deep temporal, for the most
part a distinct and single branch ; but it is not
unusual to find the buccal nerve give off one or
both of the deep temporals, or in rare cases all
the three former branches: in some instances
also it arises double, the two filaments, of
which it is then composed, being separated by
a portion of the external pterygoid muscle. It
runs downward and forward, passing at first
either and for the most part through the exter-
nal or between the two pterygoid muscles, be-
neath the external and external to the internal ;
having traversed the pterygoid it descends in
front of its inferior part, internal to the coronoid
process of the lower jaw, and the inferior part
of the temporal muscle, next between the ten-
don of the temporal and the buccinator, then
between the anterior margin of the masseter
and the latter muscle, and finally emerging
from between them it inclines toward the angle
of the mouth, superficial to the buccinator and
beneath the dense expansion by which that
muscle is covered. During its descent it is
immersed in the fat which occupies the lower
part of the zygomatic fossa. The ramifications
which it gives off are numerous; first while
traversing and immediately after escaping
from the pterygoid it gives branches to the
muscle ; at the same time it gives off a
fasciculus of branches which pass outsvard, in
front of the external pterygoid to the internal
surface of the temporal muscle, at its inferior
part ; some of these descend with the muscle

ti 2

292

FIFTH PAIR OF NERVES.

toward its insertion, and are distributed to it at
that point, others ascend in the temporal fossa,
between the muscle and the bone, penetrate the
muscle, and are distributed, along with the
branches of the anterior deep temporal, with
which they anastomose freely, to the muscle at
its inferior anterior part. In the next place,
while between the masseter and the buccinator,
the nerve gives off backward several branches,
three or four, which are distributed to the buc-
cinator at its origin, to the buccal glands, and
to the membrane of the mouth ; as it lies upon
the last-named muscle, between the ramus of
the jaw and the angle of the mouth, it gives
filaments to it at its middle and anterior part,
which, like the former, both supply the muscle,
pass through its fibres, and are distributed also
to the buccal glands and membrane. Finally,
as the nerve approaches the angle of the mouth,
it divides into two, occasionally three, branches;
these two branches pursue the direction of the
nerve toward the angle, passing beneath the
facial vein and inclining, one upward, the other
downward; after a short course they are united
both to branches of the portio dura, the inferior
to a branch of the inferior or cervico-facial divi-
sion, the superior to one of the superior or tem-
poro-facial division of that nerve. By their
union they form conjoined branches or loops,
from each of which are given off several fila-
ments to the muscles of the mouth at their in-
sertion into the angle ; from the superior, more
particularly, to the buccinator, the zygomatic,
and levator anguli; and from the inferior to the
buccinator and depressor anguli oris.

4. The fifth and last of these branches is the
plerygoid ; it is the smallest of them, and
arises from the anterior internal part of the
trunk ; it passes inward and downward, be-
hind the external pterygoid, and then between
the internal pterygoid and circumflexus palati
muscles ; it gives a filament of some size to
the latter muscle, and then entering into the
internal pterygoid at its upper extremity, it is
consumed altogether in that muscle.

The external pterygoid also, at times, but
not uniformly, receives a distinct filament from
the trunk; when present it arises from the
front of the nerve, beneath the buccal branch,
and passes forward directly to the muscle, in
which it is consumed. The constitution of
these branches is peculiar, and is a matter
of much interest: involving physiological ques-
tions, this subject is deferred to another oc-
casion.

In consequence of its connection with the
third division of the fifth, and more particularly
with the lesser packet of the nerve, this seems
a fit place to advert to the ganglion discovered
by Arnold, and by him denominated Otic
or auricular, of which the following sketch
has been taken from his own account. It
is situate at the inner side of the third branch
of the fifth, some lines beneath the foramen
ovale, at the part where the deep temporal,
the masseteric, and the buccal nerves are de-
tached from the same side, and a little above
the origin of the superficial temporal nerve:

its posterior part touches the middle meningeal
artery, and the internal the internal pterygoid
muscle : an abundant adipose tissue surrounds
it : its form is not altogether regular, however
it approaches to an oval, flattened internally
and externally. It is united to the trunk
of the third division not merely by cellular
tissue, but by many filaments, which enter
into the formation of the ganglion ; these
filaments, which come solely from the lesser
portion of the nerve, are mostly extremely
short, and can only be observed when we
try to separate the ganglion from the trunk;
but in cases where the ganglion is situate
rather distant from the nerve, the filaments
are of course longer and can be more easily
observed. With regard to the branches of
the third division, the pterygoid nerve espe-
cially is in very intimate connection with the
otic ganglion, so that in a superficial examina-
tion it appears as if it arose from it; but,
in a more accurate investigation, it is clear
that this nerve soon after its origin penetrates
through a part of the substance of the ganglion
and takes up some of it : the slender branch,
which ramifies in the tensor palati, is likewise
in very intimate relation with this ganglion,
and distinguishes itself from the other branches
by its reddish appearance. The ganglion thus
communicates with the lesser packet of the
fifth : it also communicates with the glosso-
pharyngeal and with the facial* and auditory
nerves by means of the nervus tympanicus.
But, the ganglion being a body which is to
be regarded as distinct from the fifth nerve,
and not part of it, a further pursuit of its
connections and properties would be here out
of place. See SYMPATHETIC NERVE.

The third division of the fifth descends from
the foramen ovale, outward into the zygomatic
fossa, posterior to the external pterygoid muscle,
before the superior part of the levator palati,
and internal and parallel to the middle me-
ningeal artery. After a course of half an inch
from the foramen, it divides for the most part
into two large branches, an anterior internal
one destined to the tongue, denominated the
lingual branch, and an external posterior one,
which is transmitted through the inferior max-
illary canal, and, escaping from this, through
the mental foramen, is distributed finally to
the muscles and integuments of the chin; this
second branch is called inferior dental, or
inferior maxillary nerve ; the latter, as has
been already intimated, appears much the
more appropriate appellation.

The first branch bears, very generally, the
name of gustatory nerve from its presumed
connection with the sense of taste; but, since
the opinion that it is the nerve in which the
sense of taste resides has been brought into
question, and since, as will appear by-and-
bye, it is at least certainly not the sole nerve
of that sense, it is obvious that that name
should be discontinued.

The manner in which the third division
finally divides is not always such as has been
described : in some instances it separates fairly

FIFTH PAIR OF NERVES.

293

into three branches, viz. the lingual, the inferior
maxillary, and the superficial temporal, and
such is the mode of division mentioned by
the elder Meckel. The writer has before him
an instance of another mode ; the inferior
maxillary arises by two roots, and the original
trunk divides into two parts; one common to
the lingual, and one root of the maxillary;
the other to the superficial temporal and the
other root: the superficial temporal is thus,
in this instance, equally an original branch
as the others, and is connected to the maxillary
by a filament, which it gives off soon after
its origin, while the maxillary is also connected
in the usual mode to the lingual : the maxillary
artery, however, passes through the loop formed
by the two roots of the former nerve.

The length of the third division from the
ganglion to its bifurcation is about three fourths
of an inch, one fourth contained within the
bone during its escape from the cranium, and
the other two between the aperture externally
and the division. When it divides into two,
the branches are, at times, of the same size,
but for the most part the inferior maxillary
is the larger; they descend at first in close
apposition with each other, but as they proceed
they gradually separate, the lingual branch
inclining inward and forward, the inferior
maxillary outward, in the course of the original
nerve, in order to gain the aperture of the
dental canal ; they thus leave between them
an angular interval, acute above, through
which the internal maxillary artery for the most
part passes. In their descent they cross, at
right angles, the artery internal to the origin
of the middle meningeal branch : in doing so
either they pass both behind the vessel, or the
lingual branch passes before, and the inferior
maxillary behind it. The two nerves are most
frequently connected, soon after their origin,
by a short and delicate branch, which passes
from the inferior maxillary to the lingual, and
forms, with the nerves, a triangle, through
which the artery passes in those instances in
which the lingual descends before it.

The nerves are situate internal to the neck
and ramus of the jaw, between the pterygoid
muscles, posterior and inferior to the external,
external and anterior to the internal ; and they
are contained in a triangular space included
between the two muscles and the jaw, bounded
superiorly by the external, beneath and in-
ternally by the internal pterygoid, and externally
by the jaw ; through this space they pass from
above downward, the lingual from behind
forward, and from without inward, the maxil-
lary from within outward, toward the aperture
of the dental canal, and holding the mutual
relation already indicated, — the lingual anterior
and internal, the maxillary posterior and ex-
ternal.

Before pursuing these branches of the third
division further, it will be well to describe
the superficial temporal nerve. This branch
has been viewed differently by different autho-
rities; by some it is accounted one of the
former set, the superior anterior branches of
the third division ; by Meckel it is described

as one of three, into which the continuation
of the nerve divides. It arises for the most
part by two, and in some instances by three,
roots ; a larger one from the inferior dental
nerve, and a smaller from the trunk of the
third division itself, given off at the same
time with its superior branches, and deri-
ved from the same source; the two roots
forming together a loop, through which the
middle meningeal artery ascends: in conse-
quence of this mode of origin it appears better
to describe it thus separately, and not to refer
it to either of the sets described. It has,
however, been already explained that in some
cases it appears to be an original branch of
the third division, one of three into which it
finally divides.

The nerve runs outward, backward, and
somewhat upward, behind the external ptery-
goid muscle, toward the back of the neck of
the lower jaw; it then passes behind it and
the condyle, between them and the auditory
canal, traversing tlie posterior part of the
glenoidal cavity of the temporal bone, and
imbedded in the process of the parotid gland,
which occupies it.

The superficial temporal nerve, while within
the ramus of the jaw, pursues a course nearly
the reverse of that of the trunk of the internal
maxillary artery in the first part of its course.
At first it is situate before the tensor palati
muscle, between it and the external pterygoid ;
then it passes between the internal lateral
ligament of the maxillary articulation and the
neck of the jaw, situate at the same time
above and in contact with the artery ; and
lastly, it is situate behind the condyle of the
jaw, between it and the meatus auditorius,
and involved in the parotid.

The nerve gives off numerous branches;
when it has reached the situation last described,
it breaks up at once into a leash of branches,
which pass off in different directions : of these
two, at times only one, are destined for the
interior of the meatus auditorius ; they ascend
toward the canal, become attached to its ex-
terior, and pass through the fibrous structure of
the tube, close to its connection with the osseous
portion : having thus gained its interior, they
are distributed to its lining membrane, its
sebaceous follicles, and the membrane of the
tympanum. Before entering the tube they give
some delicate filaments to its exterior; these
branches may be called the internal auricular.

Others, the smallest which the nerve gives
off, descend along the external carotid artery,
are in part distributed to the parotid gland,
and establish upon the artery a manifest com-
munication with branches of the sympathetic.
Its next branches, two in number, pass out-
ward through the substance of the parotid,
behind the neck of the jaw ; one external or
superficial, the other internal to the temporal
artery; and turning forward round the posterior
margin of the jaw, either they both, having
given some fine ramifications to the gland,
join the tern poro- facial branch of the portio
dura, immediately before its division, or one
of them joins the facial branch of the tern-

294

FIFTH PAIR OF NERVES.

poro-facial, while the other continues forward,
upon the face, below the zygoma, and deeper
than the branches of the temporo-facial : it
divides into numerous long filaments, of which
some join both branches of the temporo-facial ;
others are distributed superficially upon the
side of the face beneath the zygoma and upon
the malar region, and, ascending over the
former part, to the inferior anterior part of
the temple, as far forward as the margin of
the orbit. These may be called the commu-
nicating branches, in consequence of the re-
markable and important communication which
they establish with the portio dura.

The next may be called external auricular ;
they ascend to the anterior part of the car-
tilaginous tube of the ear, concealed by the
temporal artery, attach themselves to the tube
in front, and are distributed to the integuments
of the concha.

Lastly, the superficial temporal nerve
emerges from the parotid gland, beneath the
root of the zygoma, between the condyle of
the jaw and the cartilaginous tube of the ear,
in company with the temporal artery, and
concealed by it : it then changes its course
and ascends with the artery behind the zygoma
and in front of the ear, upon the temple : there
it emerges from beneath the artery, posterior
to it, and divides into branches, which become
subcutaneous, run superficial to the fascia and
the artery beneath the subcutaneous cellular
structure, and are ultimately distributed to the
integument of the temple : their number is
two or three ; they may be distinguished into
anterior, middle, and posterior, and they are
destined to the corresponding parts of the
temple : they correspond in their course, but
by no means regularly or strictly so, to the
branches of the temporal artery, from which
they are separated by the fascia.

Of the two terminal branches of the third
division, the larger one, the inferior maxil-
lary or dental, descends outward to the upper
orifice of the inferior maxillary canal. In
its course it passes always behind the inter-
nal maxillary artery, and soon glides between
the internal lateral ligament of the temporo-
maxillary articulation, and the ramus of the
jaw, descending in front of the anterior margin
of the ligament, which thus becomes interposed
between it and the lingual branch, and also be-
tween it and the internal pterygoid muscle, from
the pressure of which the ligament is considered
to protect it. In that situation it is joined by the
inferior dental artery, a branch of the internal
maxillary given off between the ligament and
the jaw, which accompanies it through its further
course. It next enters the canal, and is trans-
mitted through it downward, forward, and
inward toward the chin, beneath the sockets of
the teeth; having reached the termination of
the canal, it is reflected upward and outward
through the mental foramen, and escapes from
the canal upon the lateral and superficial surface
of the jaw, at either side of the chin ; at its
exit it is beneath the second bicuspid tooth of
the lower jaw, and covered by the muscles of
the lip : it then terminates by dividing into two

branches, called inferior labial nerves, external
and internal. The branches of the inferior
maxillary are as follow : — presently after its
origin it gives off the branch by which the
lingual branch and the inferior maxillary are
connected, and which completes the loop
through which the internal maxillary artery
passes ; also the branch which forms a root of
the superficial temporal nerve. Next, imme-
diately before entering the dental canal, it gives
off a long slender branch, denominated mylo-
hyoid nerve; this branch descends forward and
inward along the inside of the ramus of the
jaw, between it and the internal pterygoid
muscle, and lodged in a groove upon the sur-
face of the bone, which leads in the same
direction, and is occasionally in part a bony
canal ; it is covered in the groove by a prolon-
gation of the internal lateral ligament, and
escapes from it inferiorly in front of the insertion
of the internal pterygoid muscle and beneath
the lingual branch ; it then passes beneath or
external to the mylohyoid muscle, between the
submaxillary gland and the internal surface of
the jaw, gains the surface of the muscle itself
and runs forward and inward above the super-
ficial portion of the gland, between it and the
muscle, and accompanied by the submental
artery ; finally, it divides into a leash of branches.
Of these one is sometimes destined to the sub-
maxillary gland ; two or three are distributed
to the mylohyoid muscle; another to the anterior
belly of the digastric, and the last passes first
between the anterior belly of the digastric and
the mylohyoid, gives filaments to the muscles
in its passage, then ascends upon the chin
internal to the belly of the digastric, and is
consumed in the depressor labii muscle.

The next branches of the nerve are those
which are given off by it while within the
inferior maxillary canal : they have two desti-
nations, viz. the roots and periosteum of the
teeth and the gum of the lower jaw. During
its course through the canal the nerve gives off
several long, slender branches, which run for
some distance within the canal, ascend thence
through the bone beneath and on either side of
the roots of the teeth, ramify as they proceed,
and distribute their ramifications to the desti-
nations which have been mentioned. The
author has never found these branches as they
are for the most part represented, viz. short
single filaments ascending almost directly into
the several fangs of the teeth : they are deci-
dedly less remarkable and less numerous in the
old subject after the fall of the teeth than in
the young. Again, at the mental foramen, and
immediately before its escape from the canal,
the nerve gives off a more considerable branch,
denominated by Cruveilhier dentaire incisif,
which is continued through the jaw toward the
symphysis beneath the canine and incisor
teeth, and distributed to them. The former
set supplies the posterior molar teeth. Accord-
ing to the general opinion the nerves of the
teeth enter the fangs through the apertures
in their extremities, and are transmitted through
them into the bodies of the teeth, to be con-
sumed in the pulp and the structure of the

FIFTH PAIR OF NERVES.

295

teeth themselves. J. Hunter, however, has
stated in his work on the teeth, that he has
never succeeded in tracing nerves into the fangs,
and the experience of the writer, sa far as it
extends, tends to confirm the doubt thus ex-
pressed; he has frequently traced the filaments
to the structure at the root of the fang, but
never into the fang, and in the jaw of the foetal
calf they may be found distributed in number
upon the membrane of the pulp, but he has
not been able to follow them into the pulp
itself.

The filaments sent into the gums from the
dental nerves, superior as well as inferior,
traverse the alveolar arch, escape from the bone
upon its gingival aspect, and at once enter the
gum : they are well represented by Arnold.

The final branches of the inferior maxillary
nerve are the inferior labial, internal and exter-
nal. Of these the internal is the larger; it
ascends toward the mouth, inclining inward,
and breaks up into a great number of ramifica-
tions, which are distributed to the depressor
labii inferioris, the depressor anguli oris, the
orbicularis, and the levator menti, also to the
integument and internal membrane of the lip,
and to the labial glands; they anastomose with
branches of the inferior division of the portio
dura. The external inclines toward the angle
of the mouth ; it also gives off a great number
of ramifications, distributed to the depressor
anguli, the orbicularis, and the insertion of the
muscles at the angle, the integument, and
internal membrane of the lip, and the labial
glands; it also anastomoses with branches of
the portio dura.

The lingual branch of the third division. —
The situation and relative size and position of
the lingual and inferior maxillary branches in
the first part of their course, have been already
described. Having crossed the internal maxil-
lary artery, the lingual branch pursues its course
downward, forward, and inward, passing first
between the pterygoid muscles in the manner
described, and then between the internal ptery-
goid and the ramus of the jaw, until it has
reached the anterior margin of that muscle;
during this part of its course it is at first
separated from the inferior maxillary nerve by
the internal lateral ligament, which is placed
between them, the lingual branch internal, the
maxillary external to it, and afterward it is
situate anterior and superior to the mylohyoid
branch of the maxillary. Having reached the
margin of the pterygoid it emerges from between
the muscle and the jaw, immediately behind
the posterior extremity of the mylohyoid ridge,
and enters into the digastric or submaxillary
space, in which it is among the parts most
deeply situate; within this space it continues to
run forward and inward, until, at the anterior
extremity, it attaches itself to the under surface
of the tongue, and is prolonged by one of its
branches to the extremity of that organ. During
its course through the digastric space, it is at
first left uncovered by the muscles inferiorly,
and in the interval between the margin of the
pterygoid and that of the mylohyoid, where it
is situate between the mucous membrane of

the mouth and the posterior extremity of the
submaxillary gland ; it then passes internal to
the mylohyoid muscle, between it and the
stylo-glossus, hyo-glossus, and genio-glossus,
and is at the same time contained in a triangu-
lar or wedge-shaped space, the base of which
is above and the apex below; this space is
bounded above by the mucous membrane of
the mouth, externally by the mylohyoid muscle,
and internally by the hyo-glossus, stylo-glossus,
and genio-glossus muscles. In it are contained
the sublingual gland, the deep process of the
submaxillary and the duct of that gland with
the lingual branch of the fifth and the ninth
nerves; in the anterior part and superiorly,
immediately beneath the mucous membrane,
is situate the sublingual gland ; at the posterior
and rather inferiorly the deep process of the
submaxillary; while the nerves and the duct
are placed at the posterior or external part of
the lingual branch of the fifth above, imme-
diately beneath the mucous membrane ; the
ninth below, along, and above the cornu of
the os hyoides, and the duct between the
nerves; but as the three parts pass forward,
the duct and lingual branch cross each other,
the nerve descending, the duct ascending be-
tween the nerve and the hyo-glossus, and in
consequence of this circumstance, at the ante-
rior part of the space, the duct is superior, the
lingual branch is intermediate, and the ninth
nerve is below. At first the lingual branch is
above the deep process of the submaxillary
gland, then it is situate internal and superior to
it, external and inferior to the duct ; as it pro-
ceeds, it is beneath the sublingual gland, and,
lastly, it ascends internal to that gland, between
it and the genio-glossus, in order to reach the
tongue.

At the posterior part of the space, the nerve
is immediately beneath the mucous membrane ;
as it proceeds it descends from, but toward
the anterior part again ascends, and is in con-
tact with the membrane as it becomes attached
to the tongue.

Having reached the anterior margin of the
hyo-glossus the nerve breaks up into three
branches, posterior, middle, and anterior. Of
these the posterior is the shortest, and ascends
almost directly; the middle runs upward and
forward, and the anterior, which is much
longer than, and at the same time inferior to
the others, almost directly forward, along the
under surface of the tongue, between the genio-
glossus and the stylo-glossus; the former
muscle internal, the latter external -to it. In
its course beneath the tongue it is accompanied
by the ranine artery, which joins it at the
anterior margin of the hyo-glossus, and is
situate inferior to it, immediately above the
mucous membrane.

The lingual nerve does not give off many
branches in the first part of its course : soon
after its origin it receives the branch of com-
munication, by which the inferior dental nerve
is connected to it. About the same point or
presently after it is also joined by the chorda
tympani. The uncertainty which has prevailed
with regard to the source of this nerve renders

296

FIFTH PAIR OF NERVES.

a more particular account of it necessary than
would otherwise be required. The chorda tym-
pani — a delicate filament — is given off from the
portio dura shortly before that nerve escapes
from the aqueduct of Fallopius, behind and be-
low the tympanum : it passes upward and for-
ward toward the tympanum, contained in a spe-
cial canal of the bone, and having reached the
back of the chamber it emerges from its posterior
wall through a small aperture beneath the base
of the pyramid ; it then attaches itself to the
outer wall of the tympanum and crosses it
toward the anterior, having first received* a
delicate filament from the sympathetic, and
running forward, upward, and outward. During
its course from the posterior to the anterior
wall it is situate at first beneath the short crus
of the incus, theu between the long crus of
the incus and the superior part of the handle
of the malleus, to which it is connected by the
lining membrane of the tympanum. Having
ascended above the internal muscle of the
malleus it changes its direction and runs down-
ward, forward, and inward along the superior
anterior part of the circumference of the mem-
brana tympani, until it has reached the anterior
wall of the chamber, from which it goes out
through the Glaserian fissure, along the tendon
of the anterior muscle of the malleus. It is
throughout excluded from the interior of the
tympanum by the lining membrane, which is
connected to it upon that side ; it is therefore
incorrect to say that it crosses the chamber.
After its escape from the tympanum the nerve
continues to descend forward and inward in
front of the levator palati muscle, and after a
course from three-fourths of an inch to an inch
long it is attached at a very acute angle to the
back of the lingual branch, becomes inclosed
in the same sheath with the nerve, and con-
tinues connected with it altogether until the
nerve has reached the posterior extremity of
the submaxillary gland: at that point the
chorda tympani divides into two parts, one of
which is despatched to the submaxillary gan-
glion, and the other continued along with the
lingual branch. By somef it is stated that it
separates from the nerve at the ganglion, and
is altogether un united to it; this, however, is
incorrect. During its descent in company with
the lingual branch there may be observed,
upon particular examination of the conjoined
trunk, a communication and identification be-
tween the nervous matter of the two nerves.

Originally the chorda tympani was regarded
as either a recurrent filament of the lingual
branch of the fifth or a branch of the portio
dura : afterwards the opinion was adopted that
it was not a branch of the portio dura, but the
cranial superficial petrous branch of the Vidian
nerve, which, instead of uniting and being iden-
tified with the portio dura, descended through
the aqueduct merely in apposition with it or
within the same sheath, separated from it again
before the nerve escaped from the aqueduct,
and constituted the chorda tympani. This view

* Bock, Meckel junior, Cloquet.
t Cloquet.

of the nature of the chord, suggested first, as it
would appear, by J. Hunter, has been advo-
cated also by Cloquet and Hirzel, and is at
present entertained by many in this country at
least; it has been objected to by Arnold, and
another has been advanced by him from obser-
vations made upon the calf and the human
subject. Hunter's account of the connection
of the nerves is as follows : " This nerve com-
posed of portio dura and the branch of the fifth
pair sends off, in the adult, the chorda tympani
before its exit from the skull, and in the foetus,
immediately after. The termination of the
branch called chorda tympani I shall not de-
scribe, yet I am almost certain it is not a
branch of the seventh pair of nerves, but the
last-described branch from the fifth pair," i. e.
the Vidian, " for I think I have been able to
separate this branch from the portio dura, and
have found it lead to the chorda tympani ; per-
haps is continued into it ; but this is a point
very difficult to determine, as the portio dura
is a compact nerve, and not so fasciculated as
some others are."* According to Arnold, nei-
ther of the previous opinions is correct ; but
the petrous nerve anastomoses with filaments
of the facial nerve, principally the external,
with which it forms a gangliform swelling at
the place at which the nerve receives it ; and
the branch which forms the corda tympani
arises from the gangliform swelling of the facial
nerve, and holds in an intimate manner to the
petrous nerve ; however it is not to be consi-
dered a continuation of the latter: it is united,
during its course, to the facial nerve by several
filaments, and consequently the chorda tympani
ought to be regarded neither as a branch of the
facial nerve nor as a continuation of the petrous
nerve, but as one composed of both.f Cru-
veilhierj: maintains that the chorda tympani is
not a prolongation of the Vidian nerve, but he
assigns no reason for his opinion. The ques-
tion at issue probably cannot be decided from
the human subject: the impediment opposed
to its satisfactory determination by the density
of the facial nerve, as admitted by Hunter, and
by the manner in which the facial and the
Vidian nerves are in it blended together at their
junction, will hardly permit the point being
accurately ascertained ; but the same diffi-
culty does not exist in other animals, and
if the disposition of the Vidian nerve at its
junction with the facial be examined, in the
horse e. g., no doubt will remain that, 1 . the
Vidian nerve certainly does not run simply in
apposition with the facial nerve, and, 2. the
chorda tympani is certainly not a mere conti-
nuation of the Vidian nerve. In the horse the
facial nerve is much less dense, and more easily
analyzed than in man, and at the point of junc-
tion with the Vidian its filaments are so free
and so loosely connected, that little more is re-
quired than to open the packet without violence
in order to display satisfactorily the disposition
of the Vidian at its junction with the facial : the

* Animal (Economy, p. 267.

t Journ. Compl. t. xxiv. p. 339, 341.

i Anatomie Descriptive.

FIFTH PAIR OF NERVES.

297

Vidian passes into the interior of the packet,
crossing its fasciculi nearly at right angles, but
rather in a reflex direction, and then spreads out
and breaks up into a number of very delicate fila-
ments with which cineritious matter is inter-
mixed, and thus a ganglionic structure is pro-
duced, which is in some instances more mani-
fest than in others, and is at the same time
connected with fasciculi of the facial nerve.
The filaments into which the Vidian separates
can be followed in both directions, some re-
trograde, and some along with the facial :
the former appear to pass partly to the auditory
nerve, as stated by Arnold, and partly to the
facial between the point at which the Vidian
joins it and the brain : they can be rent from
the one into the other, and indeed look more
like filaments from the facial to the Vidian than
from the latter to the former. The latter fila-
ments of the Vidian are dispersed among the
fasciculi of the facial, with which they become
united, and can be followed by means of a
careful dissection for some distance : their
number the writer is not prepared to state : the
fasciculus of the facial from which the chorda
tympani more particularly arises, appears deci-
dedly to receive one or it may be more. Fur-
ther, the chorda tympani does not arise by a
single root, but is formed by two or three de-
rived from different parts of the facial. The
opinion that the chorda tympani is a continu-
ation of the Vidian nerve appears, therefore, to
the writer altogether unfounded, and while he
admits that the conclusion of Arnold may proba-
bly be well-founded, with regard to its compound
nature, he yet must dissent from the opinion that
the branch which forms it arises immediately
from the gangliform swelling of the facial • the
fasciculus, from which its principal root pro-
ceeds, existing distinctly upon both sides of,
and consequently not arising from the swelling,
however it may receive an accession from, or be
affected by its connection with this part. The
author cannot refrain from regarding the chord
as a branch of the facial nerve in the same sense
with any other branch arising within the limits
of the influence of the Vidian nerve. Magendie
maintains that the chord is a continuation of
the Vidian, because the section of the fifth nerve
itself deprives the ear of all sensibility, but
whatever part the chord may play in the sensi-
bility of the ear, and it is doubtful that it plays
any, the result of the experiment will be easily
explained by the doctrine of Eschricht, that
the facial nerve owes its sensibility to the fifth
nerve, the division of which must in such case
influence through the Vidian nerve any branch
of the facial arising within the range of its in-
fluence.

After the junction of the chorda tympani
with the lingual branch, the latter gives at times
a small branch to the internal pterygoid mus-
cle : during its descent along the ramus of the
jaw, it also^ gives filaments to the arches of the
palate, to the mucous membrane of the cheek,
and to the gum of the lower jaw. While the
nerve is situate between the mucous membrane
of the mouth and the submaxillary gland, it is
connected by means of two, three, or four fila-

ments with the submaxillary ganglion. This
ganglion is a small reddish body resembling the
spheno-palatme ganglion in size, colour, and
consistence, situate above the posterior extre-
mity of the submaxillary gland, and connected
superiorly with the lingual branch by the fila-
ments mentioned ; inferiorly there arises from
it a considerable number of very delicate nerves,
which descend through the divisions of the
gland, anastomose with each other, and are
distributed for the most part to the substance
of the gland ; one of them descends upon the
hyoglossus, anastomoses with a filament from
the ninth, and enters into the genioglossus
muscle, and another long one accompanies the
duct of the gland. A filament of communi-
cation also from the superior cervical ganglion
of the sympathetic reaches the submaxillary
ganglion by following the course of the facial
artery, and is represented by Arnold.

The filaments by which the ganglion is con-
nected to the lingual branch, are, as has been
stated, two, three, or four ; they are not attached
to the nerve all together, but one or two some
lines before the others, and they are remarkable
for the circumstance, that the posterior descend
forward, while the anterior descend backward ;
on attentive examination it is found that the
posterior are derived one from the chorda tym-
pani, and the other from the lingual branch
itself; it also appears that the filament derived
from the former source is but a part of the cord,
the remainder being continued on with the
trunk of the lingual, and again that the anterior
filament or filaments, which descend backward
to the ganglion, are continuations of the poste-
rior, which, after having been connected to the
ganglion, ascend forward from it again to the
trunk of the nerve. The course of those fila-
ments of connection is well described and re-
presented by the elder Meckel, and a very accu-
rate delineation of them is given by Treviranus
and Arnold. To this connection probably it
is, that we are to attribute the influence which
impressions on the organs of taste, or even
sounds exert upon the salivary apparatus ; let
us, when hungry, only hear a sound associated
in our minds, in any way, with the gratification
of our appetite, and at once that apparatus is
roused into activity.

Next, while lying between the mylohyoid and
the hyoglossus muscles, the lingual nerve sends
off from its inferior side some branches, which
descend upon the hyoglossus, and anastomose
with filaments ascending from the ninth nerve.
At the same time, from its superior side, it
gives filaments ; some of which, the posterior,
are distributed to the mucous membrane and
to the gum of the lower jaw ; others, the ante-
rior, to the sublingual gland, and by some of
their ramifications to the membrane and the
gum. Lastly, the nerve divides at the anterior
margin of the hyoglossus into its lingual
branches ; these are, at first, three, poste-
rior, middle, and anterior ; they pass up-
ward and forward^ and divide, each into
two or three branches, which altogether di-
verge from the nerve, and are ranged in suc-
cession from behind forward, along the line

298

FIFTH PAIR OF NERVES.

of separation between the stylo-glossus and the
genio-glossus ; they traverse the substance of
the tongue toward its superior surface and mar-
gin, and run along its inferior surface, above
the mucous membrane, toward its extremity ;
as they proceed they subdivide, and thus re-
sults a great number of filaments, the course
of which through the tongue is remarkable;
they appear not to terminate, any of them, in
the substance of it, but they traverse it as long,
slender, single filaments, unconnected with its
structure until they approach its superior sur-
face, when they break up into pencils (to
adopt the phrase used) of still more delicate
filaments, which may be followed into the mu-
cous membrane ; the posterior filaments of the
posterior branch insinuate themselves internal
to the hyoglossus, and reach as far back as the
foramen coecum ; the filaments of the anterior
are distributed to the extremity of the tongue,
and are continued between the under surface
of it and the mucous membrane very near to
the tip, the substance of which they then tra-
verse in order to reach its superior aspect and
margin : they thus supply the mucous mem-
brane of the organ upon its superior and lateral
parts, from the foramen ccecum to its point.

Ganglion of the fijth nerve (Ganglion
semilunare Gasseri). See Jig. 140, 9. — The
ganglion of the fifth nerve is a body of crescentic
form, a cineritious colour, and firm consistence.
It presents two surfaces, two margins, and two
extremities : its surfaces are both slightly pro-
minent, and are directed one upward, outward,
and forward, the other downward, inward,
and backward ; they are also, the former con-
cave and the latter convex longitudinally, the
ganglion being somewhat curved upon itself in
the same direction : they are both for the most
part adherent to the laminae of dura mater,
which form the chamber in which the gan-
glion is contained ; but it is not uncommon
to find the arachnoid membrane prolonged
beneath it, so that its inferior surface in such
instances is free ; the superior corresponds to
the cranial cavity in its middle fossa, being
excluded from it only by the dura mater ; the
inferior rests, with the intervention of dura
mater also, upon the petrous portion of the
temporal bone, the great ala of the sphenoid,
and against the outer side of the cavernous
sinus. The margins of the ganglion are di-
rected one forward and downward, the other
backward and upward ; the anterior is convex,
and to it are attached the three great trunks,
which compose the ganglionic portion of the
nerve in its third stage ; the posterior is con-
cave and presents through its entire length a
deep groove, into which the fasciculi of the
ganglionic packet of the nerve are received.
The extremities are obtuse, and project beyond
the packet at either side; they are situate re-
latively, one superior, internal, and anterior to
the other. When the ganglion is in situ, the
chord of the arch which it forms is six or
seven lines long ; Niemeyer has sometimes
found it amount to from nine to ten:* its width

* De origine pans quinti nervorum ccrebri mono-
graphia, Halae, 1812.

is about two lines, and its thickness, according
to the part, from half a line to a line. Its
colour and appearance vary much according
to the subject : the former is always of a cine-
ritious tint of different degrees of intensity ;
when the subject is wasted, flabby, or anasar-
cous, it is pale or grey, while, if the subject
have been robust and corpulent, it is of a deep
brown colour : in the former case also a plexi-
form arrangement is more perceptible, whereas
in the latter the ganglion seems composed of
two concentric arcs, an anterior of lighter
colour and manifestly plexiform character, and
a posterior of very deep colour and apparently
homogeneous indeterminate texture, devoid al-
together of the plexiform appearance.

A particular inquiry into the structure and
probable function of the ganglion of the fifth
nerve would involve that of the cerebro-spinal
ganglia in general, and will be better post-
poned to another occasion : it will suffice for
the present to state that according to both
Monro and Scarpa, they are composed in
part of nervous chords, and in part by a
soft grey or brown substance, which fills
the intervals between the nervous filaments,
and which according to the former resembles
the cortical matter of the brain, while in the
opinion of the latter it is a cellular texture
filled by a matter, which varies in character
according to the subject; thus he states that he
has found it fatty in fat and watery in anasar-
cous subjects. 2. That nervous filaments can
be traced through them without interruption
from the nerves situate above to those situate
below the ganglion, which opinion is objected
to by Niemeyer, who compares the connection
of the former with the ganglion to that of the
foetal and maternal portions of the placenta ;
but inspection suffices to satisfy one that this
idea of Niemeyer is incorrect; for whether
additional filaments be furnished or not by the
ganglion, the continuity of filaments above
and below it is evident even in the human
subject, and is still more manifest in other
animals : in the horse it is easily seen, par-
ticularly after a section of the ganglion.

The question whether the ganglion receives
filaments from the sympathetic system has
been a subject of dispute among anatomists.
The elder Meckel* denies the existence of any
filaments of connection between the sympa-
thetic and the fifth nerve, while within the
fibrous chamber or while situate by the cavern-
ous sinus ; and others also, among whom are
Eustachius, Haller, Albinus, and Morgagni,
are of the same opinion ; but later investiga-
tions have put it beyond doubt that such a
communication does exist. Bockf has de-
scribed filaments of the sympathetic united to
the trunk of the fifth, before the formation of
the Gasserian ganglion, and which join chiefly
the fasciculi of the trunk, from which the
ophthalmic nerve originates. And Arnold

* Scriptores Neurologici Minores, torn. i.

t Beschreibung des funften Nervenpaares und
seiner Verbindung mit andern Nerven, vorzliglich
mit dcm Gangliensystem, 1817.

FIFTH PAIR OF NERVES.

299

states " that several very delicate filaments go
from the carotid plexus to the semilunar gan-
glion, particularly to the first and third branches
of the nerve, and upon those points the gan-
glionic matter is accumulated in greater abun-
dance."* Besides this connection between the
sympathetic and the ganglion, others exist
between it and the branches of the ganglion.

The ganglion appears to constitute an essen-
tial part of the fifth nerve throughout verte-
brate animals, and to be uniformly present.
It also presents in all the common character
of being composed both of white and cineri-
tious matter, though the comparative amount
of the two constituents varies according to
the class, the order, or even the individual.
The presence of the two structures the author
would regard as essential to the constitution
of cerebro-spinal ganglia, and he would ex-
clude from such those enlargements presented
by nerves in certain situations, but from which
cmeritious matter appears to be absent. In
Mammalia, Birds, and Reptiles, the fifth nerve
is provided with a single ganglion, but in Fish
and in both orders of that class it possesses
for the most part two ganglia and two gan-
glionic fasciculi; this however is not uniformly
so, for in some, e. g. the lophius piscatorius,
the ganglion is single.

VITAL PROPERTIES OF THE FIFTH PAIR
OF NERVES. — The discussion of the vital
properties of the fifth nerve the writer pro-
poses may be fitly arranged under the following
heads: 1. its sensibility; 2. its influence upon
the faculties of sensation and volition, as also
upon the ordinary sensibility of the parts to
which it is distributed; 3. its relation to the
special senses and connection with the function
of nutrition.

1. Sensibility. — Numerous experiments per-
formed and repeated by different physiologists
have established the fact, that the fifth nerve
enjoys exquisite sensibility. Bell appears to
have been the first who directed attention
particularly to this point : in his paper, pub-
lished in the Philosophical Transactions for the
year 1821, it is stated that, touching the su-
perior maxillary branch of the fifth nerve,
when exposed in an ass, " gave acute pain."
In the first of Mayo's experiments upon the
fifth nerve, published in his Commentaries
in 1822, it was also found that " on pinching
the opposite extremities" (those connected with
the brain) " of the infraorbital and inferior
maxillary nerves in an ass, the animal struggled
violently as^ at the moment of dividing the
nerves: these latter results uniformly attend
the division of the nerves above-mentioned, and
of that branch of the fifth which joins the
portio dura."f Similar results were obtained
by the writer last quoted from experiments
of the same description upon the dog and the
rabbit, and upon the pigeon, in regard to the
first division of the fifth. He also found
" that on pinching the gustatory nerves in
living rabbits pain was evinced." Magendie

* Journ. Compl. torn. xxiv.

t Commentaries, No. 1, p. 110.

carried the inquiry farther, and in the fourth
volume* of the Journal of Physiology, has
related an experiment in which he exposed
the fifth nerve within the cranium in the rabbit
and dog, and found that the slightest touch
produced signs of acute sensibility. From
the preceding facts we infer that the ganglionic
portion of the nerve at least is exquisitely
sensitive, and that it is endowed with sen-
sibility through its entire extent: further, the
experiment of Magendie indicates that the sen-
sibility of the nerve is proper and independent
of the influence of other nerves, he having ex-
perimented upon it at a point prior to its
junction with any other.

With regard to the non-ganglionic portion
of the nerve, our data are at present altogether
analogical: it is so situated that satisfactory
experiments upon it separately are hardly to
be accomplished, so that we are left to infer
of it as probable what has been ascertained
of other non-ganglionic nervous cords, yiz. the
anterior roots of the spinal nerves. The
question in regard to the functions of the
different portions of the spinal nerves has been
inquired into by Magendie, by whom the
endowments of both sets of roots have been
tested in various modes, and who has inferred
that the anterior roots are not devoid of sen-
sibility, and if they be sensitive it is probable
that the lesser packet of the fifth is sensitive
also.t

2. Influence of the fifth nerve upon sensation
and volition. — It is hardly necessary to remark
that this point has been the subject of much
dispute, as well with regard to the fact itself
as to the relative claims of the several inquirers
to whom we are indebted for the investigation
of the matter: however, physiologists now
seem to be generally agreed that the nerve
is one of compound function, being subservient
to both the faculties of sensation and volition,
and that the faculty of sensation is dependent
upon its ganglionic, that of voluntary motion
upon its non-ganglionic portion, and that it
thus resembles the spinal nerves. That the
nerve is one of compound function, and sub-
servient to the two faculties, was announced
by Bell in the paper already alluded to. He
there distinguishes the nerves into two classes ;
one original and symmetrical, the other super-
added and irregular. To the former class he
refers the spinal nerves, the suboccipital, and
the fifth nerve, and assigns to them the fol-
lowing characters, namely, they have all double
origins; they have all ganglia on one of their
roots ; they go out laterally to certain divisions
of the body ; they do not interfere to unite
the divisions of the frame ; they are all mus-
cular nerves, ordering the voluntary motions
of the frame ; they are all exquisitely sensible,
and the source of the common sensibility of
the surfaces of the body : to it he refers the
nerves of the spine, the suboccipital, and the
Jiflhnerve.l It has been already stated that

* P. 314.

t Journal de Physiologie, t. ii. p. 368.

$ Philosophical Transactions, 1821, p. 404.

300

FIFTH PAIR OF .NERVES.

he had ascertained by experiment that the fifth
nerve was exquisitely sensitive ; that it is the
source of the sensibility of the parts to which
it is distributed, he has also determined, for
in allusion to the fifth he says, " if the nerve
of this original class be divided, the skin and
common substance is deprived of sensibility;"*
and " by an experiment made on the 16th
of March, it was found that, on cutting the
infra-orbitary branch of the fifth on the left
side, the sensibility of that side was completely
destroyed." f The experiments of Bell were
repeated by Magendie, and a similar result,
so far as regards the sentient properties of the
fifth, obtained, as mentioned in the Journal
de Physiologic, Octobre 1821. A similar
result has been obtained also by Mayo in his
experiments upon the fifth nerve, as detailed
in his Commentaries for August 1822, more
than a year after the publication of Bell's
paper. In his first experiment the infra-orbital
and inferior maxillary branches were divided
on either side in an ass, where they emerge
from their canals, and the sensibility of the
lips seemed to be destroyed : and, in a second
experiment, the frontal nerve was divided on
one side of the forehead of an ass, when the
neighbouring surface appeared to lose its sen-
sibility : the same effect was produced by the
division of that branch of the fifth which joins
the portio dura, inasmuch as the cheek loses
sensation upon its division. From these ex-
periments Mayo concluded that the facial
branches of the fifth are nerves of sensation.
The experiments upon the influence of the
nerve on sensation have been carried still
further by Magendie; he divided the nerves
within the cranium, where they lie against
the cavernous sinus, and also between the pons
Varolii and the petrous portion of the temporal
bone, and in both instances he obtained the
same result with regard to the sensibility of
the parts to which the nerves are distributed,
viz. total loss of sensibility on one or both
sides of the face, according as one or both nerves
were divided ; this extended not only to the
integuments as in the former trials, but also
to the lining membrane of the nostrils, to the
conjunctiva, to the tongue and the interior
of the mouth. The effect upon the nostril was
so remarkable that the most active effluvia,
even those of ammonia and acetic acid, pro-
duced no impression upon it: in like manner
neither piercing instruments nor ammonia ex-
cited any sensation when applied to the con-
junctiva, and the tongue was insensible to the
action of sapid bodies at its anterior part.

From such accumulated evidence but one
conclusion can be drawn, viz. that the fifth
is the nerve of general and tactile sensation
to the face and its cavities, or to the parts
upon which it is distributed.

With regard to the influence of the fifth
nerve upon volition, it has been already stated
that Bell had announced it, as one of his regular
or symmetrical nerves, to be " a muscular

* Philosophical Transactions, 1821, p. 405.
t Ibid. p. 417.

nerve ordering the voluntary motions." This
conclusion with regard to the fifth nerve he
adopted in consequence of the following ex-
periment, and of the result, which, as he
conceived, he obtained from it. " An ass being
tied and thrown, the superior maxillary branch
of the fifth nerve was exposed. Touching
this nerve gave acute pain. It was divided,
but no change took place in the motion of
the nostril ; the cartilages continued to expand
regularly in time with the other parts which
combine in the act of respiration; but the
side of the lip was observed to hang low, and
it was dragged to the other side. The same
branch of the fifth was divided on the opposite
side, and the animal let loose. He could no
longer pick up his corn; the power of elevating
and projecting the lip, as in gathering food,
was lost. To open the lips the animal pressed
the mouth against the ground, and at length
licked the oats from the ground with his tongue.
The loss of motion of the lips in eating was
so obvious, that it was thought a useless cruelty
to cut the other branches of the fifth." The
inference here indicated is obvious, viz. that
the motion of the lips in eating depends upon
the superior maxillary branches of the fifth
pair, so far at least as the distribution of those
branches extends; and what he conceived he
had thus established with regard to one branch
he inferred analogically of the rest. The
opinion that the fifth is a muscular nerve as
well as one of sensibility Bell also maintains
in later writings, and supports by additional
experiments : thus, in his Exposition of the
Natural System of the Nerves, published in
1824, he says, " to confirm this opinion by
experiment, the nerve of the fifth pair was
exposed at its root, in an ass, the moment
the animal was killed ; and on irritating the
nerve the muscles of the jaw acted, and the
jaw was closed with a snap. On dividing the
root of the nerve in a living animal, the jaw
fell relaxed." That the fifth is to a certain
extent a nerve of voluntary motion is univer-
sally admitted, but then a question arises of
equal interest and delicacy ; of interest for
its own nature, and of delicacy because of the
personal claims and feelings involved in it.
The question is, — it being admitted that the
nerve is one of double function, — is such
function enjoyed equally by all its branches
and by both its portions ; and if otherwise,
upon which do they severally depend ? From
the extracts quoted it is evident that no dis-
tinction in function between the different
branches of the nerve was contemplated by
Bell at the time the first was written, in 1821,
and that he regarded them as being all alike
nerves of compound function, — nerves both
of voluntary motion and sensation ; and, such
being the case, either that he had not recognised
a difference between the properties of the gan-
glionic and the non-ganglionic portions of the
nerve, or that he was then not aware of the
peculiar distribution of the latter ; nor is any
express information afforded us upon the subject
in his earlier writings, or antecedent to 1823.
The conclusion to which he had arrived with

FIFTH PAIR OF NERVES.

301

regard to the nerve generally and its superior
maxillary branch in particular, in the year
1821, has been stated ; in his communication
to the Royal Society in 1823, he adds, " all
the nerves, without a single exception, which
bestow sensibility from the top of the head
to the toe have ganglia on their roots ; and
those which have no ganglia are not nerves
of sensation, but are for the purpose of or-
dering the muscular frame:" from this, when
applied to the fifth nerve, it might be inferred
that sensation depended upon its ganglionic,
and muscular action upon its non-ganglionic
portion. But between the years 1821 and
1823 additions had been made by others to
the knowledge of the functions of the fifth
nerve which require notice. It is to be borne
in mind that Bell inferred from his first ex-
periment, published in 1821, that the superior
maxillary nerve is one both of sensation and
voluntary motion to the lips (see the preceding
page) : to this conclusion Magendie was the first
to object, for in the Journal of Physiology for
October of the same year (1821), he says,
" we have repeated these experiments along
with Messrs. Shaw and Dupuy, and the result
which we have obtained agrees perfectly with
that which we have just related, with the ex-
ception always of the influence of the section
of the infra-orbital upon mastication, an in-
fluence which I have never been able to perceive."
In August 1822 Mayo published, in his Com-
mentaries, his " experiments to determine the
influence of the portio dura of the seventh,
and of the facial branches of the fifth pair
of nerves." Those relating to the latter point,
which have been already alluded to, are as
follow. 1 . The infra-orbital and inferior max-
illary branches of the fifth were divided on
either side, where they emerge from their re-
spective canals ; the lips did not lose their
tone or customary apposition to each other
and to the teeth ; but their sensibility seemed
destroyed : when oats were offered it, the
animal pressed its lips against the vessel which
contained the food, and finally raised the latter
with its tongue and teeth. On pinching with
a forceps the extremities nearest the lips of
the divided nerves, no movement whatever
of the lips ensued : on pinching the opposite
extremities of the nerves, the animal struggled
violently, as at the moment of dividing the
nerves. Some days afterwards, though the
animal did not raise its food with its lips,
the latter seemed to be moved during mastica-
tion by their own muscles."

2. " Some days after, the frontal nerve was
divided on one side of the forehead of the
same ass, when the neighbouring surface
appeared to have lost sensation, but its muscles
were not paralysed." 4, 5, and 6. The branch
of the fifth, that joins the portio dura, was
divided on either side : in the fourth experi-
ment, the under lip at first appeared to fall
away from the teeth ; at times the lips were
just closed : in the fifth and sixth, the under
lip did not hang down, and no difference was
observed between the action of the muscles of
either side ; but, he observes in a later publi-

cation, " the cheek loses sensation upon its
division." The results of these experiments,
while they confirm fully the inference drawn
by Bell with regard to the influence of the
nerve over sensation, are altogether at variance
with that of his experiment relating to the con-
trol of the superior maxillary nerve over mus-
cular motion, and are equally incompatible
with the doctrine that the branches of the nerve,
which were the subjects of experiment, have
any direct connexion with muscular contrac-
tion ; for while, on the one hand, the division
of the nerves was followed by total loss of
sensibility in the lips, on the other, the latter
did not fall away either from each other or
from the teeth, nor did irritation of the portions
of the nerves connected with the lips excite
any movement whatever of those parts, but
they seemed afterwards to be moved during
mastication by their own muscles. Mayo in-
ferred accordingly from his experiments, " that
the frontal, infra-orbital, and inferior maxillary
are nerves of sensation only, to which office
that branch of the fifth which joins the portio
dura probably contributes." A circumstance
in the first experiment doubtless seems at
variance with the conclusion which Mayo has
drawn, and demands consideration here, be-
cause, unless unexplained, the fact is inconsis-
tent with the inference. It has been stated
that both in Bell's and Mayo's experiment, the
animal ceased to take up its food with its lips
after the division of the facial branches of the
fifth, and from that circumstance chiefly the
former appears to have inferred that the motions
of the lips in eating depended on these nerves ;
but the inference is objected to by Mayo as
" a theoretical account of the fact that the
animal did not elevate and project its lip ; this
fact," he says, " was noticed in my own expe-
riments, but appeared to me from the first
equally consistent with the hypothesis, that the
lip had merely lost its sensibility, as with Mr.
Bell's explanation," that it had lost its muscu-
lar power. The fact may be obviously ex-
plained by either of the two suppositions, and
it is very remarkable that it should occur
equally in one case as in the other. In the
one, the muscles of the lips having been de-
prived of their power of voluntary contraction,
the lips themselves cannot, of course, be made
use of to take hold of an object ; and in the
other, the animal not being made aware of the
contact of the food in consequence of the loss
of sensation, volition is not exerted, nor are
the muscles called into action in order to take
hold of it. To the latter cause it is attributed
by Mayo, after the division of the branches of
the fifth, and he confirms this view of its pro-
duction by reference to the effect of anaesthesia
in the human subject : " in that dfsease the
sensation of the extremities is wholly lost,
while their muscular power remains. Now it
is remarkable that in persons thus affected the
muscles of the insensible part can only be
exerted efficiently when another sense is em-
ployed to guide them, and to supply the place
of that which has been lost : a person afflicted
with anaesthesia is described in a case quoted

303

FIFTH PAJH OF NERVES.

by Dr. Yelloly, as liable on turning her eyes
aside to drop glasses, plates, &c. which she
held in safety so long as she looked at them ; "
but that the absence of motion in the lips on
the division of the fifth is due to the loss of
sensation merely, and not of voluntary power,
is positively proved by the effect of the division
of the portio dura on the two sides, an experi-
ment performed for the first time by Mayo : in
it the voluntary motion of the lips is altogether
lost, while sensation continues unaffected,* and
hence the division of the fifth cannot deprive
them of voluntary power, but only of sensation.
The explanation of Mayo has been admitted
and adopted by Bell himself in his " Exposi-
tion," 1824, in which he has added to the
detail of his experiment, as already related,
the following note : " what I attributed to the
effect of the loss of motion by the division of
the fifth, was in fact produced by loss of sen-
sation ; " and he corroborates this by the case
of a gentleman in whom loss of sensation in
the lip had been produced by extraction of a
tooth. " On putting a tumbler of water to his
lips, he said, ' Why, you have given me a
broken glass : ' he thought that he put half a
glass to his lips, because the lip had been de-
prived of sensation in one half of its extent ;
he retained the power of moving the lip, but
not of feeling with the lip." The last particu-
lar noted is of great value, as demonstrating
satisfactorily the separation of the two facilities,
and, taken in connexion with anatomical con-
siderations, renders it necessary to refer them
to separate sources. It is manifest, then, that
the circumstance of the animal not taking up
the food by means of the lips, after the divi-
sion of the fifth nerve, is not proof that it had
lost the voluntary muscular power of them,
but only that it did exert it, not having been,
as it were, apprised of the necessity of doing
so. It is also stated by Bell, that on the
division of the nerve upon one side, " the side
of the lip was observed to hang low, and it
was dragged to the other side." This result
also is objected to by Mayo, first, as contrary
to his observation, for in his first experiment,
after the division of the infra-orbital and inferior
maxillary nerves, " the lips did not lose their
tone or customary apposition to each other and
to the teeth;" and secondly, as being the
effect of an extensive division of the muscular
fibres, a cause quite adequate certainly to
explain the fall of the lip, independent of the
influence of the nerves. The difficulty, there-
fore, which these circumstances appear at first
to present is removed, and we are left to deter-

* It will be satisfactory to those interested in
this question to know, that the result of Mayo's
experiment has received full confirmation from
those of others; and first from Shaw, who has
bestowed so much labour to establish the respiratory
connexion of the portio dura. In the Medical and
Physical Journal for December, 1822, he writes,
" immediately on cutting the nerve (the portio
dura) on both sides, the lips became so paralyzed
that the animal could no longer use them in raising
its food." The same result has been obtained by
Mr. Broughton in experiments upon the horse, as
detailed in the same Journal, June, 1823.

mine the question by other means, and they
are abundantly furnished from other sources.
In the first place, the division of the nerves
completely destroys the sensation of the parts
to which they are distributed, without pro-
ducing any effect upon the tone or contractile
power of those parts, nor does irritation of the
divided nerves excite muscular contractions.
Secondly, were these nerves the source of the
voluntary powers of the parts they supply, the
division of every other nerve must fail to affect
that power while the former remain entire;
but Mayo, in several instances, divided the
portio dura alone on both sides, and the
result was, that " the lips immediately fell
away from the teeth, and hung flaccid," and
could not be used by the animal to take hold
of food, and consequently had lost ail volun-
tary power ; while, " when the extremity,
nearest the lips, of either divided nerve was
pinched, the muscles of the lips and nostrils
on that side were convulsed." Bell doubtless
asserts that after the division of the portio dura
nerve on one side, the animal " ate without
the slightest impediment;" to this Mayo
objects that " the experiment is inconclusive,
because the nerve was not divided on both
sides ;" but in truth the experiment is quite
conclusive, for though the animal can eat, and
without impediment, his eating is far from
perfect, and the imperfection is not the less
obvious because confined to one side.

When an animal which has had the portio
dura divided upon one side only takes food,
the lips remain motionless upon that side; and
when it masticates, the lips continue in the
same state, while on the other side they ac-
tively co-operate, the food and saliva escaping
on the side at which the nerve has been cut,
and on the other being confined within the
mouth. Now, if any action of the lips be
voluntary, it is assuredly that by which they
co-operate in the prehension and mastication
of food ; and since no action of their muscles
can be excited by irritation of the branches of
the fifth nerve, while such action can be ex-
cited by that of the portio dura, and all volun-
tary action is destroyed by the division of that
nerve, but one inference remains, that of Mayo
already adverted to, viz. — that those branches
of the fifth in question possess no influence
upon the voluntary faculty of the muscles ;
that they are exclusively sentient ; and that the
contractile power of the muscles of the face,
whether voluntary or involuntary, is to be attri-
buted to another source.

After what has been stated, we must admit
that Mayo has been the first expressly to an-
nounce that the function of these nerves is
restricted to sensation. Beyond that, however,
he has not gone, in reference to the question
of sensation, in the publication alluded to,
though it must be admitted that little remained
to be added in order to complete the conclu-
sion, that the ganglionic portion of the nerve is
exclusively sentient. At the same time he
inferred, " from the preceding anatomical
details," — viz. their exclusive distribution to
muscles, — " that other branches of the third

FIFTH PAIR OF NERVES.

303

division of the fifth are voluntary nerves to the
pterygoid, the masseter, the temporal, and
buccinator muscles." Here again he has not
reached the conclusion, though he has fallen
but little short of it, and though, as in the
former instance with regard to sensation, he
has been the first to announce a restriction of
the motor properties of the nerve to particular
branches. The opinion expressed by Bell, in
June 1823, has been already quoted, and
from it we are bound to admit, that then at least
he recognised the distinction at present acknow-
ledged with reference to the appropriate function
of the ganglion ic and non-ganglionic portions.
But in Mayo's Commentaries for July 1823, the
conclusion is for the first time expressly stated
thus : — " In the last paper of the preceding
number, I mentioned that the division of the
supra-orbital, infra-orbital, and inferior max-
illary nerves, at the points where they emerge
from their canals upon the face, produces loss
of sensation, and of that alone, in the corres-
ponding parts or the face. I have since, after
the division of the fourth branch which emerges
on the face, — namely, that which joins the
portio dura, — ascertained that this branch like-
wise is a nerve of sensation, inasmuch as the
cheek loses sensation upon its division. I
mentioned in addition that I concluded that
other branches of the fifth nerve, from their
distribution, are voluntary nerves. Now it is
well known that the fifth nerve at its origin
consists of two portions ; a larger part, which
alone enters the Gasserian ganglion, and ano-
ther smaller, which does not enter, but passes
below the ganglion to join itself with the third
division of the fifth. Towards the close of
last summer I endeavoured to trace the final
distribution of this small portion in the ass,
and succeeded in making out that it furnishes
those branches, which are distributed exclu-
sively to muscles : I have since ascertained
that in the human body precisely the same
distribution exists. But the lemaining branches
of the fifth are proved to be nerves of sensation ;
thus it appears that the fifth nerve consists of
two portions, one of which has no ganglion,
and is a nerve of voluntary motion (and pro-
bably of muscular sensation); and another,
which passes through a ganglion, and furnishes
branches, which are exclusively nerves of the
special senses."

We return now to the question of the pro-
perties of the non-ganglionic portion of the
fifth nerve. It has been stated that Mayo was
the first to announce the restriction of the
voluntary influence of the fifth to certain
branches, and that he was led to this conclu-
sion from the observation of the fact that certain
branches of the nerve are distributed exclusively
to muscles. These muscles he has stated, in
the first part of his Commentaries, to be the
pterygoid, the masseter, the temporal, and
buccinator; to which he has added, in his
second part, the circumflexus palati ; by dis-
section he ascertained that as well in man as
in the ass, the lesser portion of the nerve " fur-
nishes those branches which are distributed ex-
clusively to muscles;" and having already

determined that the ganglionic portions of the
nerve are destined exclusively to sensation, he
came to the conclusion that the non-ganglionic
portion is a nerve of voluntary motion. His
first conclusion upon this point he himself
states to have " involved a trifling error : the
pterygoid, masseter, and temporal muscles are
indeed exclusively supplied by the fifth, and
therefore, without doubt, the branches so dis-
tributed are voluntary nerves, but the bucci-
nator receives branches from the portio dura as
well, and I have found subsequently, that
pinching the branch of the fifth that perforates
the muscle, produces no action in it : and in
accordance with this view he writes in his
Physiology,* " I was led to observe that there
were muscles which received no branches from
any nerve but the fifth ; these muscles are the
masseter, the temporal, the two pterygoids,
and the circumflexus palati. After some care-
ful dissection, I made out that the smaller
fasciculus of the fifth is entirely consumed
upon the supply of the muscles 1 have named."
The determination of the constitution and
function of the bucral branch of the inferior
maxillary nerve has become a matter of greater
importance since the publication of Bell's
work on the Nervous System in 1830. In it
he says, " I am particular in re-stating this,
because from time to time it has been reported
that I had abandoned my original opinions,
whereas every thing has tended to confirm
them." Now, it will be remembered that
Bell's original opinion is, that the muscles of
the face are endowed with two powers, a volun-
tary one, dependent on the fifth nerve, and an
involuntary respiratory one, dependent on the
portio dura ; also, that in the first instance he
attributed the voluntary power of these muscles
to the facial branches of the fifth, but that he
had abandoned that idea, and acknowledged
that what he had attributed to loss of motion
was in fact due to loss of sensation. In the
work adverted to he has taken new ground,
and at the same time reiterates his first opinion
with regard to the existence of the two distinct
contractile powers in the muscles of the face,
and attributes to the buccal nerve that influence
over their voluntary motion which he had
before referred to the infra-orbital, &c. Thus,
" but finding that the connexion between the
motor root and the superior maxillary nerve
proved to be only by cellular texture, and con-
sidering the affirmation of M. Magendie and
those who followed him, that the infra-orbitary
branch had no influence upon the lips, I pro-
secuted with more interest the ramus buccinalis
labialis," — the buccal nerve, — " and nobody,
I presume, will doubt that the distribution of
this division confirms the notions drawn from
the anatomy of the trunk, not only that the fifth
nerve is the manducatory nerve as it belongs
to the muscles of the jaws, but also that it is
distributed to the muscles of the cheek and
lips to bring them into correspondence with
the motions of the jaws." To the point at
issue the writer has directed particular atten-

* 1833, p. 261.

304

FIFTH PAIR OF NERVES.

tion : he has made repeated dissections of the
distribution of the lesser packet of the nerve
both in the horse and in man, and after a care-
ful examination, it appears to him that Mayo
is essentially right, though the view given by
him does not exactly agree with the^arrange-
ment of the nerve as found by the author
either in the horse or in man. In the former the
masseteric branch arises from the lesser packet
by two fasciculi, one of which runs round the
ganglionic portion of the third division of the
nerve, and joins the other and larger fasciculus
before it : the facial portion of the buccal
nerve appears to the author to be purely gan-
glionic, but the root of the nerve in part
appears to be derived from the non-ganglionic
portion and is not ; and in part may or may
not be considered to proceed from it. It is
entangled at its origin with fasciculi of that por-
tion, more or fewer of the filaments which it
derives from the ganglionic packet passing be-
tween and even interlacing with fasciculi of the
non-ganglionic ; but by a patient proceeding
these may be traced to their proper source, and
the nerve be extricated from this connexion. It
is, however, difficult to accomplish it at times,
at others it is sufficiently easy. Again, one or
more branches of the non-ganglionic portion
accompany the buccal nerve for some distance,
connected to it more or less intimately, but
apparently not enclosed within the same sheath,
though communicating with the nerve by fila-
ments from a ganglionic fasciculus and separa-
ble without injury to either. These branches,
however, separate from the nerve again for dis-
tribution before it leaves the zygomatic fossa ;
they may be considered, or not, to belong to
the nerve, but they do not affect the question
with regard to its facial portion ; and the author
believes that the arrangement described is not
uniform, the branches adverted to not always
accompanying the buccal nerve.

Again, on the one hand it has been already
shewn that division of the portio dura on both
sides deprives the facial muscles of all inde-
pendent* contractile power, whether voluntary
or involuntary ; and on the other, Mayo has
found that irritation of the buccal nerve does
not excite contraction in those muscles : the
author has taken occasion several times to
repeat the experiment of Mayo upon the latter
nerve after it had emerged upon the face, and
he has not succeeded in obtaining contraction
of the facial muscles thereby, while the strug-
gles of the animal, excited by the irritation of
the nerve, proved it to be one of exquisite sen-
sibility. It appears then to the author impos-
sible to admit that the facial muscles either
possess two contractile powers dependent on
distinct nerves, or that they derive any volun-
tary power from the fifth.

It is extraordinary that Magendie, who was
the first to detect the error into which Bell had
fallen with regard to the influence of the infra-
orbital nerve over the motions of the muscles

* This expression has been used because the
muscles may be still excited to contraction by irri-
tation of the portion of the nerve connected with
them.

of the face, and has, according to his own
report, divided the portio dura on animals,
should, notwithstanding all that has been
written upon the subject, have adopted the
opinion that the muscles of the face are en-
dowed with the two distinct faculties of motion,
one of which is derived from the fifth. His view
will be found at page 703-4, Anatomic des
Systemes Nerveux, &c., and the opinion there
expressed is implied in a note at page 191,
Journal de Physiologic, t. x. In the former
he says, " Now Mr. Charles Bell in England
and M. Magendie in France by cutting the
facial nerve have paralyzed the respiratory
motions of all the side of the face correspond-
ing to the nerve cut. But the muscles which
receive at once filaments from the facial nerve
and from the fifth pair were paralyzed only in
their action relative to respiration and to the
expression of the physiognomy."

The influence of the fifth nerve upon the tac-
tile sensibility of the parts with which it is con-
nected has been discussed : its influence upon
their ordinary sensibility also requires notice.
From the preceding details it appears esta-
blished that it is to the same nerve that this
property also of the parts in general is due;
but there is reason to believe that the nerve
exerts a more extended control over this faculty
than was at first supposed. At the commence-
ment of the inquiries into the functions of the
nerves of the face, the opinion generally held
was that the facial nerve — portio dura of the
seventh pair — was devoid of sensibility. Fur-
ther observations, however, showed that this
conclusion was erroneous, and that the insen-
sibility to any injury done to the nerve in
question manifested by the subjects of experi-
ment, and from which the inference had been
drawn, was only apparent, and to be referred
to the constitution of the individual animal or
of its species. The sensibility of the facial
nerve having been established, a question arose,
whether that property was independent and
proper to it, or whether it was conferred by
another ? Those who first observed the sensi-
bility of the nerve adopted the former opinion ;
but considerations entitled certainly to much
weight led Eschricht to suspect that the facial
nerve is not endowed with independent sensi-
bility, and that the sensibility which is manifested
when it is injured is conferred on it by the fifth
nerve. In order to determine the question he
performed a series of experiments in which he
divided the fifth nerve within the cranium upon
one side after having opened the cavity and
removed so much of the corresponding hemi-
sphere of the brain as was necessary for the
accomplishment of his purpose : the facial
nerve of the same side was then exposed, and
its properties tested. The faculties of the
animal are so little affected by the removal of
the brain, that the result of the experiment
seems free from objection, while all influence
of the fifth nerve upon the sensibility of the
facial or other parts must be destroyed. In his
first successful experiment irritation of the
facial excited spasms of the lips, and also in-
dications of suffering so decided that a doubt

FIFTH PAIR OF NERVES.

305

could not be entertained : the fifth nerve had
also been fairly divided : thus far, therefore,
his conjecture was disproved. Pursuing his
inquiry still further, he found in his next
experiment that no indication whatever of pain
was manifested by the animal on irritation of
the facial on the side on which the fifth nerve
had been cut ; but in two succeeding experi-
ments he ascertained that while irritation of the
nerve anterior to the meatus auditorius pro-
duced no other effect but spasms of the nasal
and labial muscles, when exerted posterior to
that point it excited manifest evidence of suf-
fering : this latter circumstance he accounts for
by the communications of the posterior part of
the facial with other sentient nerves besides the
fifth, and he has come to the conclusion that the
former nerve is not endowed with independent
sensibility, but that it derives the property from
the fifth and other sentient nerves : this ques-
tion, however, requires further investigation.*

Relation of the fy'th pair of nerves to the
special senses. — The organs of the special senses
are in the higher classes and in the case of
smell, sight, and hearing, each supplied with
nerves from at least two sources. Besides the
particular nerves, which are generally consi-
dered to be the source or medium of the spe-
cial sense, they are furnished with branches
from the fifth pair; and a question must, at the
outset, be asked in regard to the two nerves
derived from these different sources, as to
which is to be considered the proper nerve of
the peculiar sense enjoyed? In connexion
with the two separate nervous supplies, it is
also to be observed that each organ enjoys two
kinds of sensibility, viz. the special sensibility,
through which sensations of the particular sense
are received, and the general sensibility, in
which the several organs of the body partici-
pate, and which is the medium through which
impressions of contact are conveyed. The exis-
tence of the special sense, the coincidence of
the particular nerve, the impairment or loss
of the special function uniformly consequent
upon the injury or destruction, whether by
disease or otherwise, of that nerve ; and the
community bo^i of function and distribution,
displayed by the nerve from which the organs
of the senses are in common supplied, have
led physiologists generally to the conclusion
that in each case the particular nerve is the
medium of the special sense, and that the
fifth nerve confers upon the organs of the spe-
cial senses general sensibility only. The con-
clusion thus commonly adopted has been at
different times called in question : thus Mery
and Brunet, in 1697, denied to the nerves of
the first pair the function of smell, and attri-

* Eschricht, de functionibus nervorum facici et
olfactus organi, Hafn. 1825, [The superficial tem-
poral nerve doubtless contributes mainly to supply
sensibility to the posterior twigs of the facial : but
so much difficulty do some see in satisfactorily
accounting for the sensibility of the portio dura,
that they find it convenient to discover two roots of
origin, and a ganglion on one, thus reducing it to
the class of compound nerves. See Arnold, Icones
capitis nervorum ; also Gaedechens, nervi facialis
physiologia et pathologia. — ED.]
VOL. II.

buted this sense to the fifth nerve.* The ques-
tion of the connexion between the fifth nerve
and the special senses is one of much difficulty,
and probably we are not as yet in possession of
sufficient data from which to draw a positive
conclusion upon it when viewed in all its bear-
ings. It resolves itself into three: 1. how far
the nerve may be concerned in the perception
of special sensations in those cases in which
nerves, considered to be specially intended for
their perception, exist: 2. how far its co-
operation or influence may be necessary to
enable the special nerves to fulfil their func-
tions: 3. how far it may be capable of taking
the place of those special nerves, and of be-
coming, under certain conditions, media of
perception to sensations, for which, in other
cases, peculiar nerves are conferred. We shall
review the relation of the nerve to the several
senses in succession, bearing in mind the three
points to which our attention is to be directed.
That it is a medium of perception in the case
of two senses, viz. touch and taste, is already
so universally acknowledged that it is unneces-
sary to dwell upon the point.

The importance of the fifth nerve in the
three other senses of smell, sight, and hearing,
has been advocated by several physiologists,
and more particularly by Magendie, who ap-
pears disposed to view the fifth nerve as the
source or medium of all the three. His appli-
cation of this doctrine, however, has reference
more particularly to the sense of smelling,
upon which he has performed a series of expe-
riments, of which the following is a summary :
he destroyed entirely the olfactory nerves within
the cranium, and he found the animal still
sensible to strong odours, such as ammonia,
acetic acid, essential oil of lavender. The sen-
sibility of the interior of the nasal cavity had
lost nothing of its energy ; the introduction of
a stylet had the same effect as upon a dog
which had not been touched. This experiment
he performed several times, and always with
the same results. He next divided the fifth
nerves within the cranium, of course before
they had given branches to the nostrils,
and found all trace of the action of strong
odours to disappear. He hence concluded that
smell, in so far as pungent smells are con-
cerned, is exercised by the branches of the
fifth pair, and that the first is not concerned in
the function. To this conclusion he himself
starts the objection that the agents used are not
odours, properly speaking, but chemical, pun-
gent, irritating vapours, and that by the section
of the fifth we destroy not the sense of smell,
but only the sensibility of the membrane of the
nose to these irritating vapours, and he admits
the force of the objection with respect to some
of the vapours alluded to ; but he denies that
it will apply to the oil of lavender or that of
Dippel, the effect of which in the experiments
is the same. In order to remove the difficulty
he destroyed the olfactory nerves of a dog of
particularly fine nose, and then enclosing por-
tions of food of various kinds in paper, he

* See Journal Complementaire, v. 20.
x

306

FIFTH PAIR OF NERVES.

presented them to the animal, and it always
undid the paper and possessed itself of the
food ; but, he adds, " I do not regard this ex-
periment as satisfactory, because in other cir-
cumstances it appeared to me to want smell to
discover food which I put near him without
his knowledge" (a son insu). However, the
latter circumstance is overlooked by Magendie,
and his conclusion is, " une fois le nerf trifa-
cial coupe, toute trace de sensibilite disparait,
aucun corps odorant a distance ou en contact,
les corrosifs memes n'affectent plus en aucune
facon la pituitaire."* Doubtless this conclu-
sion is qualified by another immediately suc-
ceeding, " that does not prove that the seat of
smell is in the branches of the fifth pair ; but
it proves at least that the olfactory nerve has an
indispensable need of the branches of the fifth
pair to be able to enter into action ; that it is
devoid of general sensibility, and that it can
have only a special sensibility relative to
odorous bodies."f The latter must be ad-
mitted to come, if not quite, at least very near
to the general opinion, but it is altogether at
variance with the former, and one is rather at
fault for the author's precise meaning. Refe-
rence to later writings, however, leaves no
doubt upon that point. In the conjoint work
of Desmoulins and Magendie (1825) upon the
nervous system of the vertebrata, besides other
similar passages, will be found the following :
" La cinquieme paire, par ses branches nasales
dans les mammiferes, et par ses branches pro-
pres a la cavite pre-oculaire des trigonocephales
et des serpents a sonnettes, est done 1'organe
de Fodorat."J Notwithstanding the weight of
Magendie's authority, a careful review of the
matter will not permit us to assent to this con-
clusion, and compels us to avow not only that
it is not proved, but that the premises justify
a contrary one. [n the first place it is not war-
rantable to call the effluvia of ammonia or
acetic acid odours : they are no more odours
than the fumes of muriatic or nitric acid ; and,
though aware of the objection, he still calls
them odeurs fortes, and bases his inference
upon their operation. But he says the objec-
tion does not apply to oil of lavender or the
animal oil of Dippel : this, however, is but an
assumption at variance with fact; in the human
subject these agents may act feebly upon the
sensibility of the membrane of the nostrils, and
may not appear to possess irritating properties ;
but this will not prove that they act similarly
upon animals, whose organ of smell is more
sensitive than that of man, and accordingly
Dr. Eschricht,§ who combats the opinion of
Magendie, has found that, on application to
the nostrils of those animals upon which the
experiments of Magendie have been performed,
they produce all the same effects which am-
monia or nitric acid does. In the second place
his experiment of presenting food to a dog,
whose olfactories had been destroyed, enclosed

* Journal de Physiologic, t. iv. p. 306.

t Ibid.

J T. ii. p. 712.

$ Journal de Physiologic, t. vi. p. 350.

in paper, and in which the animal undid the
paper, upon his own showing not only does
not justify his inference, but, so far as it
reaches, proves the contrary. To establish his
position the animal must have discovered the
food by smell, without knowing that it was in
the paper ; but it is manifest, from Magendie's
own relation, that when the animal undid the
paper, it knew, or was led by some circum-
stance to expect the food to be in it ; but that
when it was not already aware or in expecta-
tion that the food was near it, it did not dis-
cover it. To the writer it seems that the na-
tural inference from the experiment, as related,
is that the animal's proper sense of smell de-
pended upon the olfactory nerves, inasmuch as
it did not display fair evidence of its presence
after their destruction, and that the sensibility
displayed by the membrane of the nostrils after
the destruction of these nerves, and dependent
upon the fifth, has reference only to those im-
pressions which are objects of tactile or general
sensation, but not of the special sense.

At the same time, however, that we express
our dissent from Magendie with regard to the
nervous connexion of the proper sense of smell,
it must be admitted that his researches posi-
tively indicate a distinction between the media
of perception in the case of different agents
operating on the olfactory organ, which it has
been too much the habit to regard as pro-
ducing their impressions all through the olfac-
tory nerves : they have gone a considerable way
in demonstrating the separation of those media;
a result which is made complete by the conti-
nuance of the simple sense after the loss of the
influence of the fifth nerve consequent upon
disease : further, they indicate that sensations
derived through the organ of smell are less
simple than they are usually accounted ; that
they may be, and probably are for the most
part, compound, resulting from the combina-
tion of impressions made upon the two senses
thus shewn to be enjoyed by the organ.

Magendie's view has been adopted, and an
endeavour made to corroborate and establish it
by Desmoulins in * Reflexions' upon a case
communicated by Beclard, an<t published in
the fifth volume of the Journal of Physiology.
The case is that of a patient, in whom the
olfactory nerves and their bulbs were de-
stroyed by the growth of a tubercular disease
from the anterior lobes of the brain ; " yet he
took snuff with pleasure, appeared to distin-
guish its different qualities, and was affected
disagreeably by the smell of the suppuration of
an abscess with which one of his neighbours
was afflicted." From this case, from that of
Serres, related elsewhere, and the experiments
of Magendie viewed in connexion, Desmoulins
has adopted the opinion that " the nerves and
lobes called olfactory are alien to the sense of
smell, or at all events co-operate so little in it,
that the sense continues to be exerted without
them ; that, on the contrary, this sense resides
essentially in the branches of the fifth pair,
which are distributed to the nostrils." Serres'
case has been discussed elsewhere; that of
Beclard appears at first unanswerable; but

FIFTH PAIR OF NERVES.

307

how will it appear after the qualification by
which it is followed has been perused ? " I
owe it to truth," he says, " to add that these
last statements were not collected till after the
dissection, and that they were gathered from
the patients of the ward." Such an admission
manifestly destroys the value of the case : evi-
dence obtained only after the individual's death,
so little marked as during his lifetime to have
been overlooked, and relating to a question at
once so obscure and delicate, can hardly fail to
be imperfect; but admitting that the patient
did relish and distinguish between different
kinds of snuff, and that he was disagreeably
affected by his neighbour's ailment, what then ?
The chief property of common, if not of every
snuff, is pungency and not odour, and the per-
ception of pungency is not the function of the
olfactory nerve; and one may be as disagree-
ably affected by a disgusting sight as by a dis-
gusting smell, and the patients of the ward not
make any distinction between the senses af-
fected, until taught by the inquiries made that
it must have been that of smell. And if the
case just quoted prove the existence in the
organ of smell of a sensibility to the impres-
sion of volatile agents independent of the ol-
factory, and conferred by the fifth nerve, the
existence of another equally independent of
the latter is satisfactorily established by the
continuance of smell in those cases in which
the faculty conferred by the fifth nerve has been
lost through disease. This may be seen from
reference to the case furnished by Beclard, and
advanced by the very advocates of Magendie's
doctrine in support of it; but the fact is still
more strongly established by the case some
time since published by Mr. Bishop, in which,
though the fifth nerve was completely destroyed
by the pressure of a tumour within the cra-
nium, and both the ordinary and tactile sensi-
bility of the same side of the face and its cavi-
ties was in consequence altogether lost, the
sense of smell continued unimpaired. In a
case of disease of the fifth nerve which the
writer has witnessed, the patient did acknow-
ledge the perception of certain odoriferous
agents ; but judging from it alone, he could
not say that smell was not impaired; on the
contrary it seemed very much so, inasmuch as
the patient denied at first any perception of
the impression of several agents accounted
odorous, and when he did say that he smelt
these, it was not of himself, nor until he had
b^en particularly questioned, and then he said
it was « up in his head' that he felt the sensa-
tion, and positive must take precedence of nega-
tive evidence. Further, it is very likely that in
the case of sensations, themselves neither dis-
agreeable nor acute, the vividness of which
may depend very much upon association with
other and more acute ones, the former may be
disregarded where the latter have been lost,
and hence the rashness of inferring that brutes
have lost certain faculties, because in the course
of experiments they do not by the exercise of
these give evidence of their existence. The
fact of the absence of olfactory nerves in the
Cetacea as established by Cuvier, has also led

some to the conclusion that the proper faculty
of smell may be capable of being transferred
at least to the fifth ; but until the faculty has
been proved to exist in such case, the inference
is manifestly not warranted by the premises.

It appears then that there is a distinct per-
ceptive faculty enjoyed by the nostrils, inde-
pendent of the fifth and dependent on the
olfactory nerve; that we possess no positive
evidence of the latter nerves being in any case
the media by which this peculiar perception is
recognized, but that they serve for the recogni-
tion only of impressions of contact, pungency,
or irritation.

2. Relation of the fifth nerves to vision. —
That in all animals having at once the faculty
of vision and an optic nerve, the latter is in-
dispensably necessary to the exercise of the
former cannot be denied : — disease or division
of the nerve is uniformly attended by loss of
the function ; but some circumstances coun-
tenance the opinion that the fifth nerve pos-
sesses a more important connection with vision
than may at first appear. 1. Injury of the
frontal and certain other branches of the fifth
nerve has been long accounted among the
causes of amaurosis. 2. Magendie has found
that " on division of the two ' fifth ' nerves
upon an animal it seems blind." 3. The fact
which countenances most strongly the opinion
that the fifth nerve is concerned directly in
the function of vision is derived from com-
parative anatomy. It has been stated that in
certain animals a special optic nerve is wanting,
and the ocular nerve is derived from the fifth
pair. Of this it appears universally admitted
that the proteus anguinus is an instance ; its
eyes are situate immediately beneath the epi-
dermis, which is transparent* in front of them ;
the optic nerve is wanting,f and the only nerve
received by the eye is a branch of the second
division of the fifth.J Whatever vision, there-
fore, may be enjoyed by this animal, and
according to Carus§ it is considerable, must
be exerted through the medium of the fifth
nerve. Among the mammalia also are several
animals which appear to be in the same, or
nearly the same state ; but anatomists are not
agreed on the point : the absence of a special
optic nerve in the mole was announced by
Zinn, || who shewed that its place was taken by
a branch of the fifth. Carus and Treviranus,
however, maintain that the optic does exist
in the animal, but that it is very minute, grey,
and capillary ; that in the same proportion
the fifth nerve is large, and that its second
division at its exit from the cranium gives
off a branch, which enters the globe of the
eye, and according to the former concurs in
forming the retina.ir Serres again positively
denies the existence of the optic nerve in the
mole, and maintains that these anatomists are
mistaken ; he states that he has sought the

* Serres.

t Treviranus, Serres.
$ Ibid.

$ Comparative Anatomy.

\\ De differentia fabrics octili human! et brutorum.
f Journal Complementaire, vol. xv.

x 2

308

FIFTH PAIR OF NERVES.

nerve with the greatest care in thirty or forty
of these animals, and never succeeded in
finding it; and also in confirmation thereof
that the optic foramen is wanting in the
sphenoid bone. According to him several
other of the mammalia are similarly constituted,
viz. the mus typhlus, the mus capensis, the
chrysochlore, and the sorex araneus. Of these
the mole, the mus capensis, and the sorex
arensis decidedly enjoy vision, the first ac-
cording to the observations of Geoffroy St.
Hilaire and Cuvier ; the second according to
those of Delalande, and the third according
to Serres himself; and if his view of the
anatomical disposition of their ocular nerve
be correct, the fifth nerve must in them also
take the place of the optic and serve as the
medium of sight. Treviranus, though he
maintains the existence of a special nerve in
the mole, yet says, from the disproportion
of the optic and the ocular branch of the
fifth, that in that animal the latter ought or
must have to fulfil in vision more important
functions than the optic nerve.* When to
these facts we add the view of the nervous
connections of the senses in invertebrate animals
advocated by Treviranus, viz. that the nerves of
the senses in them are all branches of the fifth
pair, the general proposition seems sufficiently
.probable, viz. that the fifth nerve is capable of
acting as a medium of perception to impressions
of light. But on the one hand, until it be
proved what the exact nature of the optic
faculty is which animals devoid of a special
optic nerve possess, the question must be held
to be undecided. It may be that the faculty
is different in the two cases ; that where the
special nerve is absent, the faculty may amount,
as suggested by Treviranus, to no more than
a mere perception of light, and that the im-
pression is then not visual, but only one. of
ordinary sensibility. Such a distinction, in
the sense in which that term is understood
in reference to the higher animals, is easily
conceived, and indeed is demonstrable from
the influence of light upon an inflamed or
irritable eye, and if such a distinction do
naturally exist, the apparent anomaly presented
by animals being sensible of light and seeming
to enjoy vision without a special optic nerve
will be removed, while such a faculty may
suffice fully for the condition of the animal.
Again, the evidence in favour of the opinion
that the fifth is directly concerned in vision
where a special nerve exists, seems altogether
insufficient. In the first place, though in-
juries involving the frontal or other branches
of the fifth nerve may induce amaurosis, it
remains to be proved that the injury of the
nerve is the cause of the disease, and that
this did not rather arise from the effect of the
injury upon other parts concerned in vision;
a view which is greatly confirmed by the fact
that the mere section of the nerve has not
been found to occasion any such affection of
vision. In the second place the experiments
of Magendie are far from satisfactory. In

* Ibid. vol. xv. p. 210.

order to determine the influence of the fifth
nerve upon vision, he performed the following
experiments, from which he inferred that the
section of the fifth nerve destroys sight without
abolishing entirely all sensibility of the eye
for light, and suggests in explanation either
that the fifth is the medium of perception, or
that it is necessary to enable the optic to act.
After having divided the fifth pair on one
side in rabbits, he threw suddenly upon the
eye the light of a wax candle, and no effect
was produced ; the same being tried upon the
sound eye, the only effect produced was move-
ments of the iris. Under the impression that
this was not sufficiently intense, he tried that
of a powerful lamp, but, even with the as-
sistance of a lens, the result was the same.
He then tried the experiment with solar light,
and by making the eye pass suddenly from
the shade to the direct light of the sun, an
impression was produced and the animal im-
mediately closed its eyelids. Such data cannot
be admitted as sufficient to justify the inference
that vision is destroyed by the section of the fifth
nerve. In the first place it is to be recollected
that the experiment was made upon rabbits, in
which Magendie has elsewhere told us that
section of the fifth nerve produces strong con-
traction of the iris, consequently great dimi-
nution of the size of the pupil : and of what
value, then, is the result that, under the in-
fluence of the light of a candle or a lamp, an
impression was not made sufficiently powerful
to cause the animal to give evidence of it?
In the second place the animal did, under all
the disadvantages, give sufficient evidence that
its vision was not destroyed ; there is, therefore,
no reason for the conclusion drawn from the
experiment related.

On the other hand. Mayo has found that
the fifth nerve may be divided within the
cranium in the cat and pigeon, and vision
continue unaffected ; which circumstance shows
that the apparent loss of vision in the rabbit
was owing to the great contraction of the pupil,
while according to Magendie's statement there
does not remain any trace whatever of sensi-
bility to the impression of light in the eye
after the section of the optic nerve. We must,
then, conclude that the optic nerve is the
proper medium of perception to visual im-
pressions, and that the co-operation of the fifth
nerve is not even necessary to enable the optic
nerve to fulfil its function. As the instrument
of the general sensibility of the structures of
the eye, however, the fifth nerve may be the
channel through which impressions not visual,
though perhaps excited by an agent of vision,
viz. light, may be conveyed.

The conclusion thus drawn from experimental
physiology is fully confirmed in man by -the
history of those cases in which the influence
of the fifth nerve has been lost from disease :
of these two have been adduced by Bell in
the Philosophical Transactions for 1823, one
from the observation of Mr. Crampton, the
other from that of Dr. Macmichael, in which
the surface of the eye was totally insensible,
whilst vision was entire ; and another, still

FIFTH PAIR OF NERVES.

309

more remarkable, has been reported by Mr.
Bishop,* in which the functions of the fifth
nerve seemed altogether obliterated by the
pressure of a diseased growth within the
cranium, and yet the patient saw distinctly
to the last, the only derangement which oc-
curred in the function of vision being the loss
of the power of distinguishing colours, which
appears sufficiently accounted for by a certain
degree of pressure exerted by the tumour upon
the optic nerve. Magendie endeavours to
support his views upon this and other points
connected with the properties of the nerve by
reference to a case reported by Serres, which
appears very inadequate, and will be discussed
by-and-bye.

Influence of the fifth nerve on hearing. —
The great affinity between the sense of hearing
and that of touch renders it more easy to
conceive how hearing might be excited through
the medium of the fifth nerve. As we have
seen that the ocular nerve in certain animals is
a branch of the fifth nerve, so is the auditory.
Among the cartilaginous fishes there are several
instances in which this occurs. The origin of
the auditory nerve from the fifth in fishes was
first announced by Scarpa,f and by him sup-
posed to apply to fish generally. This view
is combated by Treviranus :J it is admitted
in part by Serres; he states that in osseous
fishes the auditory nerve is united at its in-
sertion with the fifth; in cartilaginous fishes,
that the auditory is sometimes confounded
with the fifth, sometimes separated distinctly
enough, as in the raia clavata. From his own
observations the writer would say, that in the
bony fishes the two nerves cannot be said to
be united or to arise the one from the other,
but only to have a common superficial attach-
ment to the medulla oblongata ; and from the
analogy of the same nerves in the higher classes
of animals, he would not admit, without
further proof, a common superficial attachment
as establishing identity of ultimate connection
with the encephalon. As to the cartilaginous
fishes, it appears to him that Serres has fallen
into an error with regard to the connection of
the auditory nerve. It appears to the writer
that the fifth and the auditory are con-
founded in the raia clavata as plainly as in
any other individual of the class ; the posterior
ganglionic fasciculus of the fifth and the
auditoiy nerve form one trunk for a distance
of some lines after leaving the medulla ob-
longata ; they are at all events enclosed within
the same sheath : § but whether they are to be
regarded as branches of a common trunk or
not, it is difficult to decide. The weight of
naalogy is certainly opposed to a conclusion

* Medical Gazette, vol. xvii.

t De Auditu et Olfactu.

$ Journ. Compl.

§ Serres seems to have overlooked the fact that
there exist two ganglionic fasciculi in the raia
clavata ; that he has assumed the anterior fasci-
culus to be the fifth, and described the posterior,
with which the auditory is connected, as the auditory
and facial nerves : the error will be manifest upon
tracing the distribution of the fasciculus.

in the affirmative ; and, though this were ad-
mitted, a difference between the auditory and
the other branches of the fifth (as supposed)
must still be admitted, inasmuch as the auditory
separates from the nerve before the occurrence
of the ganglion, and has not itself a ganglion.
On the other hand the auditory may be se-
parated from the rest of the nerve, after the
division of the common investing membrane,
with little or no laceration of fibres. Still it
may be asked why, if they be distinct nerves,
are they united into one trunk? The opinion
that the fifth nerve holds an important in-
fluence over the sense of hearing derives support
from the circumstance, that in most, if not
all, the cases of disease of the nerve, the
sense of hearing becomes impaired, though
not obliterated.

The last question proposed to be considered
with reference to the functions of the fifth
nerve is its connection with nutrition.

The opinion that the nerve controls the
nutrition of the parts which it supplies has
been advocated by Magendie, more particularly
with regard to the eye. It has been already
stated that we are indebted to this writer for
information in regard to results of the division
of the entire trunk of the nerve within the
cranium. Of these the most prominent is
the entire loss of sensibility on the same
side of the face, and in regard to the eye
especially, loss of sensibility in the conjunc-
tiva, upon which the most irritating chemical
agents then produce no impression. These
immediate effects of the section were followed
by others not less remarkable: on the next
day the sound eye was found inflamed by
the ammonia, which had been applied to it,
while the other presented no trace of inflam-
mation. Other changes, however, supervene.
The cornea of the eye of the side on which
the section is made, twenty-four hours after-
wards begins to become opaque ; after seventy-
two it is much more so ; and five or six days
after it is as white as alabaster. On the second
day the conjunctiva becomes red, inflames,
and secretes a puriform matter. About the
second day the iris also becomes red and in-
flames, and false membranes are formed upon
its surface. Finally the cornea ulcerates, the
humours of the eye escape, and the globe
contracts into a small tubercle. In endeavouring
to ascertain the cause of these changes, Ma-
gendie, on the supposition that they might
be owing either to the continued exposure of
the eye to the air or to the want of the
lachrymal secretion, divided the portio dura
in one rabbit, the effect of which is to destroy
the power of closing the eyelids; and from
others he cut out the lachrymal gland; but
in neither case did opacity of the cornea suc-
ceed. The sequence of the effects mentioned
after the section of the nerve might naturally
lead us to infer that the loss of nervous in-
fluence gives rise to them. But such is not
the inference drawn by Magendie, nor indeed
can it be admitted : absence or subtraction
of an influence cannot be directly the cause
of an alteration in the condition of an object

310

FIFTH PAIR OF NERVES.

otherwise than by allowing it to come or return
to a state from which it is preserved by the
presence of the influence; and there is no
good reason, either theoretical or experimental,
for believing that the state induced in the
case under consideration is one in which the
eye would necessarily be, which, in fact,
would be natural to the organ but for the
restraining influence exerted through the fifth
nerve.

It is easy to imagine that the absence of
such an influence should render a part slow to
take on any vital action ; though even this,
until proved, is an assumption — an assumption
which we are induced to adopt from the fre-
quency with which sensation and pain are
found associated with the establishment of cer-
tain vital processes, more particularly inflam-
mation, but which is, on the other hand, con-
tradicted by the readiness with which inflam-
mation and its consequences are excited in
parts whose nervous faculties are impaired or
destroyed by agencies which make little or no
impression when those faculties are retained,
and which must be demonstrated before admit-
ted, since it is manifest from the occurrence of
that process after the destruction of all trans-
mitted influence at least, that the principle —
the main-spring of it must reside elsewhere;
and hence that, if in the natural state the nerve
influence the process at all by means of such a
property, it can be only in the character of a
secondary and controlling power. It does,
however, seem proved by the result of Magen-
die's experiment, that the interruption of the
influence did retard the inflammatory process,
inasmuch as the eye, on the side of the undi-
vided nerve, was very actively inflamed the day
after the application of ammonia to it, whilst
the other eye did not present any trace of in-
flammation ; a circumstance by the way diffi-
cult, if not impossible, to reconcile with the
doctrine that the process of inflammation is
directly influenced in either way, whether posi-
tively or negatively, by the power of the nerve ;
and further, that the division of the nerve
should diminish the vital powers of the eye,
and thereby render it less able to resist the
effects which inflammatory action tends to pro-
duce. But indeed there does not appear any
reason for admitting that the alterations which
took place in the condition of the eye were
produced directly by the loss of nervous influ-
ence. Having, as he conceived, disproved, by
the experiment related, the idea that the alte-
rations were owing to the continued exposure
of the eye to the air, or to the want of the
lachrymal secretion, — the only other causes
which appear to have occurred to him, — Ma-
gendie arrived at a conclusion the opposite of
that just mentioned, and adopted the opinion
that the phenomena " depend upon an influ-
ence purely nervous"* exerted by the fifth nerve
upon the eye, — " an influence independent of
the connection of the nerve with the spinal mar-
row," f — an influence " proper to the nerve,

* Anatomic dcs Systemes ncrvcux, £c. t. ii.
p. 716.

t Journal <le Physiologic, p. 304.

which has not its source in the cerebro-spinal
system, and which is even the more energetic,
the farther we remove from that system to a
certain distance," of which the following is his
proof. " Alterations of nutrition in the eye are
the less complete, the less rapid, as we remove
farther from the point of branching of the nerves
of the fifth pair, and as we cut, within the cra-
nium, the fasciculus of origin the nearer to its
insertion ; finally, the section of the nerve on
the margin of the fourth ventricle no longer
produces any alteration in the state of the
eye." * In this view there are plainly two posi-
tions advanced, viz. that the nerve does itself
exert a proper and independent influence upon
the nutrition of the eye, and that it is the sec-
tion of the nerve which causes the exercise of
that influence, or, to use his own words, which
is the cause of the inflammation, &c. That
the occurrence of the alterations in the eye, in
the case in question, is not due to an influence
exerted by the brain through the nerve, and
that it must proceed from another cause, and
that not dependent upon the connection be-
tween them, is manifest, since it is consequent
upon the interruption of that connection ; and
therefore, if the nerve do possess the supposed
influence, it must be a proper and independent
one : but are we, therefore, to infer that the nerve
does exert such an influence upon the organ ?
It appears to the writer that we cannot : for can
we suppose that the nerve is endowed with a
property to be displayed expressly under cir-
cumstances, which it is fair to say were not
contemplated in the establishment of natural
laws, viz. in cases of mutilation? or is it possi-
ble that a separate influence can exist in the
nerve and increase in energy in proportion as
the nerve is curtailed ; for the nearer the section
is made to the eye, the more remarkable are
the effects ; or if any other proof that the nerve
does not possess such an influence be wanting,
can we suppose that it is possessed for the eye
and not for the other parts to which the branches
of the nerve are distributed ? Why does not
inflammation forthwith assail the nostrils, the
mouth, and cheeks upon the mere section of
the nerve,f as well as the eye ? Manifestly be-

* Op. cit. ibid.

t It is stated by Professor Alison, Outlines of
Physiology, p. 147, that inflammation, ulceration,
and sloughing are produced sometimes on the mem-
brane of the nose and on the gums by section of the
fifth nerve, " as was first ascertained by Magendie."
The only passages approaching at all to this state-
ment, which the author has found in Magendie's
writings, are at page 181, Journal de Physiologic,
t. iv, and page 717, Anatomic des Systemes Ner-
veux, &c. Desmoulins et Magendie, t. ii. In the
first he says, " when a single nerve is cut, there
appear alterations in the nostrils, the mouth, the
surface of the tongue on that side ; the half of the
tongue becomes whitish, its epidermis is thickened,
the gums quit the teeth ; the alimentary matters
sink into the intervals which are formed ; probably
because the animals having no longer their atten-
tion attracted by the sensation of the tendency of
the matters to pass between the teeth and the
gums, push them thither without perceiving it •/'
and in the second, " a part of the broken food re-
mains on that side, between the teeth and the
cheek, and its contact terminates by ulcerating the

FIFTH PAIR OF NERVES.

311

cause no such influence exists; and indeed the
data upon which it has been assumed, instead
of proving the position, leave it precisely as it
was ; for insomuch as the occurrence of the
phenomena upon the section prove the exist-
ence of the influence of the nerve, in the same
degree does the absence of the phenomena
upon the section of the nerve disprove it.

But was the inflammation caused by the
section of the nerve ? This question, which cer-
tainly ought to have been determined satisfac-
torily before a theory had been founded upon
the assumption, appears to the writer to have
been decided too hastily in the affirmative. If
the section were the cause, no sufficient reason
can be assigned why it should occasion inflam-
mation in one part, to which the nerve is distri-
buted, and not in another, yet such is the case;
the eye is the only part in which inflammation
supervenes, either so uniformly or so quickly
as to afford any ground for attributing the pro-
cess to the section. In the second place, were
the section the real and essential cause, it can-
not be supposed either on the one hand that
non-essential circumstances could influence, or
at all events prevent the effect, or on the other,
that they could produce it. Now it will pre-
sently appear that both the one and the other
may take place ; and a comparison of Magen-
die's experiments and their results would alone
suffice to shew that the real cause is to be
sought elsewhere than in the section of the
nerve. Magendie divided the nerve in three
different situations; first, through the temporal
fossa ; secondly, within the cranium, between
the Gasserian ganglion and the pons Varolii ;
and thirdly, at the margin of the fourth ventri-
cle ; and his own general account of the results,
which has been already cited, is as follows :
" those alterations in the nutrition of the eye are
the less complete, the less rapid, as we recede
more from the point of branching of the nerves
of the fifth pair, and as we cut, within the cra-
nium, its fasciculus of origin the nearer to its
insertion ; finally, the section on the margin of
the fourth ventricle no longer produces any
alteration." It is plain, then, that the nerve
may be cut, and the changes in the eye ensue
or not, according to circumstances to be yet
explained. On the other hand, that effects
similar in kind, if not equal in degree, may be
produced by circumstances not essential to their
production, — according to the doctrine main-
tained, but incidentally associated with the
supposed cause, — that such effects may be pro-

buccal membrane." In neither of those extracts is
there mention of inflammation or sloughing ; and
the ulceration which is mentioned, is attributed to
another cause than the section of the nerve. On
the other hand, the writer has frequently divided
the lingual branches of the fifth nerve and pre-
served the animals for months afterward, and he
has been unable to detect any change in the condi-
tion of the tongue, except this, that in some the tip
of the organ, from being allowed to remain between
the teeth, and thus to be exposed to injury, ulce-
rated, and this continued until the tip was re-
moved, when the extremity of the organ healed,
and it appeared to be in all other respects as
before.

duced by such circumstances, when dissociated
from the other and operating separately, the
author feels justified in asserting, from the re-
sult of some experiments lately made by him-
self, which lead to the conclusion that similar
effects may be produced without the section of
the nerve at all, and that an injury in the vici-
nity of the orbit may excite them though nei-
ther the trunk of the fifth itself, nor its ophthal-
mic division have been divided. In an endea-
vour to determine the nerves of taste, he under-
took the removal of the ganglion of Meckel
from the dog ; in order to accomplish this it was
necessary to displace the zygoma and the coro-
noid process of the jaw ; he attempted it seve-
ral times before he succeeded, and failed at
different stages of the operation ; but in almost
every instance the eye of the same side became
bleared within the next two days. The animal
kept it nearly closed : a whitish puriform mat-
ter was discharged from it, in quantity propor-
tioned to the case, which concreted between
the lids ; and the animal made no attempt to
remove the matter or cleanse the eye : the affec-
tion of the eye was always proportioned to the
violence done, and abated with the inflamma-
tion of the wound ; and in one of the instances
in which the ganglion was removed, it actually
produced opacity of the cornea, and ulceration
in that structure, which continued after the
lapse of more than a month from the operation ;
yet most assuredly neither infra-orbital nor
ophthalmic nerves had been divided. Thus,
if, on the one hand, the nerve may be cut and
the changes not ensue, on the other it may be
left uncut, and the changes may occur.

It may be objected that the effects here de-
scribed fall very far short of those which took
place in the experiments of Magendie. That
they fall short of those which occurred on the
division of the nerve in the temporal fossa is
quite true, but it is equally so that they far ex-
ceed those consequent upon the section at the
margin of the fourth ventricle. The objection,
therefore, would be devoid of weight, and if
we suppose superadded to the violence already
done when the nerves are not divided, the ad-
ditional violence necessarily inflicted in the
division of them, we shall have a ready expla-
nation furnished of the higher degree to which
the effects produced amount in one case than
in the other.

From the preceding considerations it appears
to the author necessary to infer, that the changes
which supervene in the eye after the section of
the fifth nerve in certain cases, take place inde-
pendently of the section, as the primary, imme-
diate, or proper cause ; for were it otherwise,
it cannot be supposed either that the difference
of half an inch to one side or the other, as re-
gards the point of section, could so influence the
cause as to prevent or allow these changes, or
that they could occur, even in degree, without it.

How, then, are the phenomena to be ex-
plained? It has been said by Magendie that
they are less marked the more we recede from
the point of branching of the nerve; but it is
to be further observed, that, as we recede from
the point of branching of the nerve, we recede

312

FIFTH PAIR OF NERVES.

also from the orbit, the eye and its appendages,
and in our operation for the division of the
nerve we do less violence either in their vicinity
or actually to them, until the operation is per-
formed at such a distance from those parts,
that they are not involved in the injury inflicted.
Thus the nerve cannot be divided through the
temporal fossa without great violence done to
the parts in the vicinity of the orbit, and con-
nected with the eye as well as the fifth nerve,
as is evident from the result, and as has been
explained elsewhere.* In the section be-
tween the ganglion and the pons, the violence
is inflicted at a part more remote than the
former, from the orbit, &c., and here, according
to his own account, the effect upon the eye
was much less considerable. But the most re-
markable fact is, that the alterations of nutrition
are much less marked than in the former mode
of experiment ; there forms only a partial in-
flammation at the superior part of the eye, and
the opacity which ensues occupies but a small
segment upon the circumference of the cornea
at the superior part ; and in the third case the
parts injured are so far removed from the eye, —
(in dividing the nerve on the margin of the
fourth ventricle, Magendie exposed the parts by
" opening the spinal envelopes between the
occiput and the first vertebra,") — that the effects
of the injury could not, under ordinary circum-
stances, extend to it, and accordingly in it no
alteration occurred. It would seem, then, that
the great violencef inflicted, either in the vici-
nity of the eye or actually to its appendages,
constitutes the primary and immediate cause of
the alterations which took place in the eye in
the experiments under consideration. But it is
likely they were the result of more causes than
one, for there were also engaged in the experi-
ments other agencies, the influence of which
must have enhanced greatly that of the violence
inflicted by the operation; thus, in the first
place, in some of the instances at least, — and
we have no evidence that it was not so in all, — .

* It is hardly possible to conceive the section
effected at the point and in the mode adopted,
without a division of most of the nerves and vessels
supplying the eye and its appendages.

t A better idea of the injury likely to be inflicted
in the experiment will be formed from a brief ac-
count of the mode of conducting it. A lancet-
pointed style is driven into the cranium through
the temporal fossa and through its base, and when
carried in to such depth as the experience of the
operator teaches him to be sufficient, its point is
moved upward and downward, until the loss of sensa-
tion in the superficial paits assures him that the filth
nerve has been divided. After such a proceeding the
question should rather be, what mischief has not
been done than what has. There cannot be any
assurance that, in the division of the fifth, the third,
fourth, and sixth nerves with the branches of the
sympathetic — nay, the optic itself — have not been
involved : and if to this be added the almost cer-
tainty of dividing the internal carotid artery, from
which the supply of blood to the internal structures
of the eye is directly derived, and the division of
which causes the death of the greater number of
the subjects of experiment, an amount of injury
will be made out, quite adequate to account for the
total loss of the eye, and which must reduce the
influence of the fifth in producing it to a low degree
indeed.

a highly irritating agent was introduced, and,
in consequence of the insensibility of the organ,
probably in considerable quantity, into the eye;
and in the second the eye was left under cir-
cumstances more than enough to excite inflam-
mation and to produce serious injury to it,
though the organ had remained in full posses-
sion of all those safeguards with which its sen-
sibility and the sympathetic action established
thereby between its several protecting appen-
dages naturally endow it ; for " the eye was
dry;" and " the eyelids were either widely
open and immoveable, or else they were glued
together by the puriform matters, which were
dried between their margins;" and an organ so
circumstanced has abundant cause for inflamma-
tion, independently either of nervous influence
or of its absence. It may be said that Magen-
die has proved that neither the open state of
the eyelids nor the want of the lachrymal secre-
tion is adequate to the effect. Admitting for a
moment that he has, he certainly has not shewn
that the combined influence of the two is inad-
equate to produce it ; but the first position is
by no means satisfactorily established: his
mode of determining the question, whether the
inflammation was excited by the eye remaining
constantly open or not, was by the division of
the portio dura, and his experiment has certainly
proved that the effect of the section of that
nerve will not excite inflammation in the eye,
but no more; inasmuch as such section does
not produce a permanently open state of the
eye : an eye so circumstanced will be closed
during sleep, and even during the waking state
it requires attention and experience in such
observations to discover that the animal has
lost the power of closing the lids by a muscular
effort of those parts themselves ; for by the sud-
den exertion of the power of retracting the eye,
which inferior animals possess to a remarkable
degree, the lids become nearly, if not quite,
closed, and the animal appears to wink as well
as before, while by rolling the eye the different
parts of its surface are in turn brought beneath
the lids, and thus no one part is ever left long
absolutely uncovered. So great indeed is the
power which brutes possess in this respect, that
the author has seen a dog in which the portio
dura had been divided on one side, presented
for observation, and persons aware that the
nerve had been divided, yet not able to disco-
ver on which side it had been done, and even
deny that the lids were paralyzed on either side,
until something was approximated to each eye
successively, when the uninjured eye was at
once closed, but the other remained open, aiuT
the animal appeared looking at the object,
which it was unable to exclude. It is obvious,
then, that the question has not been and cannot
be determined in this way.

To the causes already enumerated must be
added the loss of the nervous influence, for it
is not intended, in what has preceded, to assert
that the section of the fifth has no share in the
production of the changes in the eye, but only
that it is not the primary or essential cause of
them. Indirectly it must contribute powerfully
to produce and aggravate, or it may even excite

FIFTH PAIR OF NERVES.

313

them ; for by destroying the sensation of the
organ, it must leave it exposed to the unin-
terrupted influence of many irritating agents,
which naturally would excite inflammation,
were it not that we are warned through the
sensibility of the organ to avoid or to remove
them, but in every such case they are the im-
mediate, and the insensibility only the mediate
cause of the effects produced, and such, it ap-
pears to the author, is the part played by the
section of the fifth in giving rise to inflamma-
tion in the eye. It is further to be observed
that the occurrence of inflammation in the
eye in cases in which the influence of the fifth
nerve upon it had been lost, had been noticed
and given to the public by Bell prior to the
publication of it by Magendie. In the Philo-
sophical Transactions for 1823, (Magendie's
memoir dates 1824,) Sir C. Bell reports the
case of a patient under the care of his colleague
Dr. Macmichael, in which the surface of the
eye was totally insensible, and the eye re-
mained fixed and directed straightforward,
while the vision was entire. " The outward
apparatus being without sensibility and mo-
tion, and the surface not cleared of irritating
particles, inflammation has taken place, and
the cornea is becoming opaque ; thus proving
the necessity of the motions of the eye to the
preservation of the organ." And in the same
volume he reports also a case from the expe-
rience of Mr. Crampton of Dublin, bearing
strongly upon the question, because it shews
satisfactorily that the sensation of the organ,
and consequently the influence of the nerve,
may be obliterated, and inflammation not
ensue until a stimulus have been applied,
though the conjunctiva manifestly retained its
susceptibility to the impression of that sti-
mulus. Mr. Crampton's account of the case
is as follows: " When she told me her eye was
dead, as she expressed it, to be certain I drew
my finger over its surface, and so far was this
from giving her pain, that she assured me she
could not feel that I was touching it at all. The
eyelids made no effort to close, while I was
doing this; but the conjunctiva appeared sen-
sible to the stimulus, as a number of vessels on
the surface of the eye became immediately in-
jected with blood."

Another circumstance may be advanced in fa-
vour of the opinion that the nerve influences the
nutrition of the parts, to which it is necessary to
allude, viz. the wasting of the muscles of masti-
cation in cases of the loss of the nerve's influence.
This fact may be otherwise explained ; the de-
velopment of muscles is always influenced by
their exercise, which being lost they waste, and
it is neutralized by the counter-fact that, though
these masticatory muscles waste, the muscles
of the face and its other structures do not. In
fine there appears to the writer to be no good
reason for attributing to the fifth nerve a direct
influence upon the nutrition of the structures
to which it is distributed; the existence of such
an influence would be incompatible with the
simplicity of natural laws, for in such case
there must be two such influences in existence,
one in the nerve directing the nutrition of the

parts with which it is connected, and another
elsewhere to direct that of the nerve.

Magendie confirms his view of the influence
exerted by the fifth nerve upon the functions
and nutrition of the eye, by reference to a case
published by Serres in the* fifth volume of the
Journal of Physiology, which " presented all
the phenomena attending section of the fifth
pair," and in which there existed complete
alteration of the trunk of the nerve in its sen-
sible portion ; " followed by loss of sight, of
smell, of hearing, and of taste on the same
side." Before detailing this case, the writer
cannot refra.n from observing that in such
cases none but unquestionable evidence can be
admitted if we would arrive at a certain and
unquestionable conclusion. Whether the case
of Serres be such, it rests with the reader to
decide; and first, what was the condition of
the patient in other respects? Serres replies :
" His air was dull; his physiognomy gave, at
first sight, the idea of imbecility; he seemed
to conceive slowly and to comprehend with
difficulty, the questions which were put to
him. When he wished to reply, it was evi-
dent that he experienced difficulty in express-
ing himself; he pronounced with difficulty,
and the little that he said seemed to require,
on his part, a considerable effort : his cranium
was voluminous compared to the rest of his
body; some pupils suspecting a commencing
hydrocephalus, thought that they observed a
separation between the parietal and temporal
bones, but the prominence of the eyes made
me reject that conjecture; the maxillary and
malar bones were a little separated, which
had produced a flattening of the nose ; the pa-
tient had some difficulty in moving the tongue;
the motions and sensibility of the limbs were
not affected, only he moved the lower extre-
mities less freely than the upper ; he had been
for some time subject to epilepsy; he had a
sister deaf and dumb." A case so complicated
as this, in which there manifestly existed ex-
tended disease of the encephalon, must be
rejected as altogether inconclusive. But to
proceed, the patient was admitted into hospital
in September 1823: at his admission he had a
chronic ophthalmia of his right eye, which was
considered scrofulous. In the course of De-
cember he was attacked by an acute ophthalmia
of the same eye, attended by adema of the lids,
and commencing opacity of the cornea; the
ophthalmia was dispersed after ten or twelve
-•days ; but the cornea was rendered altogether
opaque throughout its whole extent; of course
the loss of vision on that side was the neces-
sary result. In the course of January 1824 it
was observed that the right eye was insensible,
and soon after that the eyelid and nostril of the
same side were also insensible, and likewise
the tongue on that side, while all was natural
on the other; soon after the gums inflamed
upon the right; they were red, some white
places existed here and there, they were swollen
at the circumference of the sockets ; the tongue
moved always with difficulty; the hearing was
not then affected ; in July the affection of the
gums extended to the left side, but the right

314

FIFTH PAIR OF NERVES.

was always more affected than the left. During
August the gums became separated on the
right from the necks of the teeth ; there existed
between the latter and the gums spaces into
which tartar and portions of food had pene-
trated ; the patient suffered from the epileptic
paroxysms with variable degrees of severity :
he next fell into a general cachexy, with extreme
debility, impeded respiration, small frequent
pulse, great alteration of countenance, and un-
usual taciturnity. It is stated that in August
he acknowledged deafness on the right, which
diminished and again increased; the sensibility
was perfectly preserved in all the extent of the
right side of the face ; the patient died on the
12th of August. Both the brain and the fifth
nerve were found after death much diseased,
the brain on the left and the nerve on the right
side.

The details of the case have been given more
at length than may perhaps seem necessary, but
the question is interesting, and as the bearing
of the case upon it could not be determined
otherwise, the writer has endeavoured to
give them faithfully. The difficulty of obtain-
ing precise knowledge from so complicated a
case has been already adverted to. We come
next to inquire how far it substantiates the
writer's views, or how far it can be considered
to establish the opinion of Magendie. Serres,
as has been already stated, announces it as an
instance of disease of the fifth nerve followed
by loss of smell, sight, hearing, &c. Surely
the loss of these several functions, thus an-
nounced, should have been satisfactorily esta-
blished, before asserted ; but such does not
appear to have been the case. For the first,
notwithstanding the announcement, we find
Serres himself, after the patient's death, ac-
knowledging, " toutefois 1'odorat n'avait pas
completement disparu, puisque,"* &c. The
sense of smell then plainly was not lost. In
the next place there was loss of vision, but
from what cause ? from opacity of the cornea,
and, so far as we have data for forming a
judgment, from it alone. We have no reason
to think that any alteration had been pro-
duced in the power of the eye to receive
sensations of light, any disturbance in the
function of the retina, or any other change
than the occurrence of a physical impediment
to the exercise of a function, which the organ
may have retained in full vigour, had it only
been allowed to exert it: the evidence, there-
fore, afforded by the case, is too imperfect to
be of value.

Let us next inquire how far it bears out the
opinion that the fifth nerve possesses a proper
and direct influence upon the nutrition of the
eye : here we shall find ourselves equally at
fault for the resemblance which it has been
sought to establish. In Magendie's experi-
ments the section of the nerve preceded the
occurrence of the phenomena, and it is reason-
able to expect, that, here, the loss of sensibi-
lity, which we are to regard as the analogue
of the section, should have preceded the oc-

* Journ. de Phys. t. v. p. 245.

currence of the inflammation of the eye ; but
no. The patient had a chronic ophthalmia, con-
sidered scrofulous at the time of his admission;
(he was admitted in September, and in De-
cember he was attacked by acute ophthalmia,
attended by oedema of the lids ; a circumstance
not noticed in any of Magendie's experiments;)
the inflammation was dispersed, and in the
course of January, and not till then, (i. e. four
months after his admission and about one after
the occurrence of the second inflammation,)
the insensibility of the eye was for the first
time observed. Surely we have no reasonable
grounds here for attributing the inflammation
of the eye and the opacity of the cornea to the
disease of the nerve, or for supposing that there
existed any connexion, in the relation of cause
and effect, between them. If we seek for a
resemblance in other points, we shall be equally
disappointed. It has been already remarked
that cedema of the eyelids, which occurred in
this case, is not one of the phenomena of
Magendie's experiments. Again, the affection
of the gums related is altogether unlike : in
Serres' case they are stated to have become
inflamed, and to have been affected on both
sides, only more on the right than on the left ;
in Magendie's it is simply stated that they
separated from the teeth and only on the side
on which the nerve had been divided ; and,
lastly, the continuance of sensibility upon the
right side of the face throughout casts an im-
pervious obscurity over the entire.

Besides those effects of the section of the
trunk of the nerve which have been discus-
sed, there are others, for which we are in-
debted also to Magendie, and which deserve
notice.

He found after the section of the nerve that
the eye was dry, and the motion of winking
had ceased ; the globe of the eye itself seemed
to have lost all its motions ; the iris was
strongly contracted and immoveable. The loss
of sensibility in the conjunctiva, and the sus-
pension of the secretion of the tears, he refers
to the loss of the influence of the fifth nerve
upon the former part and upon the lachrymal
gland : the explanation of the first is in accor-
dance with the previously established proper-
ties of the nerve as already ascertained by Mayo,
but it is not equally so that the secretion of
the lachrymal gland is directly controlled by
the same influence, and it remains to be deter-
mined whether the effect in this case was not
an indirect one, consequent upon the previous
insensibility of the conjunctiva. The other re-
sults of the section — the immobility of the
eyelids, that of the eye, and the permanent
contraction of the pupil — he has not satisfac-
torily explained : the immobility of the lids
may, it appears to the author, be attributed
with much probability to the insensibility of
the conjunctiva or of the internal structures of
the eye, and seems a likely consequence there-
of: the ordinary action of winking would seem
to be called into play through the sensations of
those structures, and the cessation of that
action upon the loss of their sensibility is as
natural an effect as the immobility of the lips

FIFTH PAIR OF NERVES.

315

on the contact of food consequent upon the
division of the infra-orbital and inferior maxil-
lary nerves : and this view derives confirmation
from the circumstance that in the instance
under consideration the immobility of the lids
is not the consequence of paralysis, for on the
sudden admission of solar light into the eye,
the action of the muscle was excited, and the
eyelids were closed. The immobility of the
eye itself the author cannot but regard as an
incidental circumstance, caused by the com-
plication to which Magendie himself refers,
viz. the division of the motor nerves of the
eye along with the fifth, and this explanation
is rendered more likely, if not confirmed, by
the effect of the section when made between
the ganglion and the brain, in which case the
motor nerves are not involved, nor the motion
of the eye affected. It is to be regretted that
Magendie has not given a report of a dissec-
tion after death of some of the animals upon
which the former experiment had been per-
formed, by which the question might have
been determined. The permanent contraction
of the iris is an extraordinary and as yet unex-
plained effect : it occurred only when the
experiment was made upon rabbits, and is
at variance with the results of similar experi-
ments upon other animals, performed both by
Mayo and by Magendie himself. In Mayo's*
experiments, which were done upon pigeons,
in no instance was contraction of the pupil
caused by division of the nerves connected
with the eye or its appendages. When the
optic nerve was divided, the pupil became fully
dilated. When the third nerve was divided,
the same result ensued ; and when the fifth
was divided, the iris contracted as usual on the
admission of light; in Magendie's experiments
again upon cats and dogs the pupil was en-
larged.-f The fact is, however, confirmed by
Mayo, who found that when the fifth nerve
was compressed in a rabbit after death, the
pupil became contracted slowly and gradually,
and then slowly dilated ; and when the nerve
was divided, the pupil became contracted to
the utmost, and remained so. A correspond-
ing difference between the conditions of the
pupil after death in the subjects of experi-
ment has been observed by Mayo, according
to whom in the pigeon and cat it is naturally
dilated, but in the rabbit, on the contrary,
contracted.};

It has been already stated that Magendie
divided the nerve within the cranium both
after and before the occurrence of the ganglion :
in the latter case — when the section is made
between the ganglion and the brain — the re-
sults are different in some remarkable respects
from those attending the section in the former :
the effect upon the senses is equally marked ;
but the motions of the globe of the eye are
preserved almost always, from which the author
would infer that the loss of those motions in
the former must have been caused by the divi-

* Comment, part ii,
t Journal, t. iv. p.
$ Physiology.

. 4, 5.

sion of the motor nerves along with the fifth,
by the side of the cavernous sinus ; and also
the changes which occur in the tissues of the
eye are much less considerable ; the inflamma-
tion and opacity ensue, but not to the same
extent.

Another very remarkable result of the sec-
tion is displayed in the animal's mode of pro-
gression as related by Magendie : " when the
two nerves are cut upon an animal it seems
blind, and its mode of progression is most sin-
gular ; it advances only with the chin leant
strongly upon the ground, pushing thus its
head before it, and using it as a guide as the
blind does his staff: the progression of an
animal in this state differs altogether from that
of an animal simply deprived of sight ; the
latter guides itself easily by means of its
whiskers, and by the sensibility of the skin of
its face ; it stops at hollows, feels obstacles,
and, in fine, it would be difficult to know
whether it is blind or not ; while the animal
whose fifth nerves have been cut has but one
mode of moving, and instead of avoiding
obstacles, it persists often in pushing against
them for several hours, so as finally to exco-
riate the skin of the anterior part of the
head."*

This account, which is well calculated to
excite at first extreme surprise, is after all
strictly consistent, and illustrates strongly the
importance of the nerves in question : in fact
to the animal so circumstanced the head and
face must be as a part which it does not possess,
or rather of which it has been suddenly deprived,
and which it yet believes itself to retain ; it can
have no consciousness of their existence, while
from habit, memory, and ignorance of the real
condition of the parts, it yet believes them to
be present, and to exercise all their usual func-
tions. Thus the human being whose limb has
been removed without any knowledge of what
has actually occurred believes that he still pos-
sesses it, acts as if he did, and is only con-
vinced of his loss by the evidence of the senses
of sight and touch. In like manner the ani-
mal acts under the impression that it still
possesses its ordinary faculties, and being
altogether unconscious of the contact of ob-
stacles in consequence of its loss of sensation in
the part which encounters them, it acts as if it
were not in contact with them, and endeavours
still to advance, while it is unable to make
use of sight, if this faculty be retained, as a
a guide, because it has lost the correcting and
regulating assistance of the sensation of its
face as exercised through its whiskers ; and
hence it does not appear to the author that the
apparent blindness of the animal proves real
blindness. Unassisted sight cannot teach us
the distance of objects ; and the animal sud-
denly deprived of the faculty of sensation may
see the object, but not being made aware of its
contact, must suppose that it has not reached
it, inasmuch as the usual notice of its presence
is not given by the sensibility of the face.

Lastly, when the nerves have been divided

* Journ. de Phys. t. iv. p. 181.

316

FOETUS.

upon both sides, the lower jaw ceases to be
supported by its muscles, and falls.*

Influence of disease on the functions of the
nerve. — The inferences drawn from the anatomy
of the nerve and from physiological experiment
conjointly have been confirmed in a remarkable
manner by the effect of disease of the nerve
upon the functions of the parts to which it is
distributed: several instances have been pub-
lished exemplifying either partially or com-
pletely that effect, when, whether from disease
of the trunk of the nerve itself or from pressure
upon it, its office has been interrupted, all the
parts supplied by it are deprived altogether of
both their tactile and ordinary sensibility : this
loss of sensibility extends to the whole of the
corresponding side of the head so far as the
distribution of the nerve reaches to the fore-
head, temple, ear, surface of the eye and its
appendages, cheek, nostril externally and inter-
nally, lower part of the face, lips, and mouth,
the corresponding half of the tongue, of the
palate, and the fauces ; upon all these parts the
roughest contact produces no perceptible im-
pression ; inflammation is not attended by
pain, the most pungent or irritating effluvia do
not affect the nostril or the conjunctiva, and
the sense of taste is altogether lost in the ante-
rior part of the same side of the tongue : at the
same time the muscles of mastication — the ex-
ternal ones at least — lose their contractile power,
remain inactive during the process and waste,
whence are produced a flattening and depres-
sion in the site of the temporal and masseter,
with prominence of the adjoining points of
bone : however the special senses continue un-
affected apparently, unless in so far as the sense
of contact may be necessary to the perfect or
ordinary fulfilment of their function, the olfac-
tory function seems much impaired ; the pa-
tient is insensible to the impression of ammo-
nia, snuff, or other pungent agent, but still ac-
knowledges a perception of odour. Vision
continues throughout, and appears unaf-
fected, unless from the supervention of in-
flammation, by which the eye may be spoiled,
or from the extension of the disease to the optic
nerve or the brain : in the case before alluded
to, which the author has witnessed, vision re-
mained perfect for a considerable time ; amau-
rotic symptoms supervened during the course
of the disease ; but even after the occurrence
of opacity of the cornea in consequence of in-
flammation, the patient could still distinguish
light. Hearing appears to have been affected
in most, if not all the cases, in which the dis-
ease had attained a considerable degree ; it was
so in the case seen by the author ; the sense of
contact would seem associated with the perfect
exercise of the sense. The facial muscles re-
tain their contractile power; in the instance
alluded to, though the temporal and masseter
seemed quite paralyzed, the buccinator acted
with energy as ascertained by holding the cheek
between the finger and thumb during its con-
tractions ; the slight want of adjustment, which
may occur about the mouth, seems caused by

* Magendic, Bell.

the want of sensation in the lips. Lastly, in
all such cases the eye of the affected side is
liable to have inflammation excited in it by
incidental causes ; for the most part this occurs
at an advanced stage of the disease, and can be
referred to some exciting cause ; it is attended
by but little, if any pain, and opacity of the
cornea is an usual result.*

(For the BIBLIOGRAPHY see NERVE.)

( B. Alcock.)

FOETUS, Gr. KV^OC.', Fr. foetus; Germ.
die Frucht ; (normal anatomy).' See OVUM.

FCETUS (abnormal anatomy). Considering
the peculiar circumstances of the foetus in utero,
we would, at first sight, be inclined to suppose
that, although of course exposed to the risk of
injury from accidents or diseases occurring to
the mother, it would not be liable to many or
serious accidents of its own ; nevertheless, ob-
servation and experience soon reveal to us a
very different state of facts, and force upon us
the sad truth that the seeds of life are often
sown adulterated with those of infirmity and
decay, that disease may mutilate, and death
destroy, even before our entrance into life ; for
as far as investigation has enabled us to reach,
we have reason to believe that the child before
birth is not only liable to certain affections
which may be considered peculiarly its own,
but is also subject to almost all those which
affect the adult.

Of these affections some appear to be, 1.
strictly innate in the constitution of the foetus;
2. some communicated by infection from the
mother's system ; 3. some from the father's sys-
tem, or perhaps through that of the mother,
she herself not being the subject of the affection
entailed, as in certain forms of syphilis, scrofula,
and small-pox ; 4. some, from strong mental
impressions on the mother; 5. some, arising
from morbid alterations in the envelopes of the
ovum, the placenta, and cord, or in the uterus
itself; 6. some, from the influence of external
agents, as falls, blows, pressure, &c.

The investigation of these abnormal con-
ditions is invested with a deep interest, not
only as an important pathological inquiry,
but as conducive to the adoption of mea-
sures calculated to be beneficial to both mo-
ther and child; to the child, by suggesting
the strong necessity for preventing the exposure
of the mother to influences likely to affect the
welfare of her unborn offspring, as well as for
removing their effects by proper remedial
means : and to the mother, by affording us
occasionally information of the existence of
diseased taints in her system, of which we
might otherwise long remain ignorant ; or by
guarding her against the ill effects of unhealthy
states of the child ; for, although each indivi-
dual has a separate existence, there is at the

* Mayo, Commentaries and Physiology ; Bell,
Philosoph. Transactions and on Nerves, 1830 ;
Serres, Journal de Physiologic, t. viii ; Noble,
Medical Gazette ; Bishop, Medical Gazette, vol.

FCETUS.

317

same time a very close and intimate mutual
dependence of the one on the other ; and, con-
trary to what we would at first expect, the
health of the mother is more apt to suffer from
morbid conditions of the fetus in utero than is
the latter to be injured in its developement by
the state of the mother's system. Thus we see
how great a disturbance is often caused in the
maternal system by a blighted ovum, or a dead
and putrid fetus ; while, on the other hand,
we frequently observe that women in states of
the most infirm health,* both mental and bo-
dily, nay even when sinking under the ravages
of some wasting disease, or depressed and worn
out by mental suffering, by want of food or ex-
cessive fatigue, give birth to full-grown and
well-thriven children.

The affections to which the fetus is liable
vary not a little according to the period of its
existence at which we consider it ; during the
earlier periods, when the formative process is
in most active operation, and the developement
of the different organs is proceeding rapidly,
many important and remarkable organic altera-
tions take place ; some from arrest of develop-
ment caused by imperfection in or morbid
alteration of the structures of the ovum ; some
by destruction of parts already formed, by
atrophy or inflammation, or both conjoined ;
some by the effects of excessive secretion and
the consequent unnatural distension, &c. ;
while those affections, to which more strictly
belong the name of diseases, affect the more
matured fetus, whose organization approaches
more closely that of the new-born child.

In order to give a full account of the morbid
and abnormal conditions of the fetus, we
should embrace also those of its appendages
or surrounding structures of the ovum ; these,
however, will be alluded to at present only so
far as is absolutely unavoidable, as they will
receive full consideration in the articles OVUM
and PLACENTA : and in like manner several
varieties of malformation will be with more
propriety described under the head of MON-
STROSITY, while others will be found under the
account of the different organs concerned.

The germ, even before its vivification in the
ovary, may have a morbid taint communicated
to it from the system of the female in whom it
resides, or from that of the man with whom she
cohabits, so that the tendency to disease or
malformation sometimes precedes the first im-
pulse that leads to the establishment of life.
Another source of abnormal conditions in the
fetus occurs in the cohesion or intus-susception
of germs, in consequence of more than one
ovulum being contained within the same vesi-
cle ; under which circumstances unnatural
union may take place between two fetuses,
and give rise to the production of such anoma-
lies in organization as the Siamese twins, or to
other forms of fetal duplicity, more or less re-
sembling the remarkable instance represented
in the annexed sketch of two children born a

* See several instances recorded by Mauriceau,
Malad. des femmes grosses, vol. ii. obs. 439, 497,
530, 622, 629, 656.

few years since at Boyle, in the county of Ros-
common.

Fig. 146.

They were born alive, and lived for more
than a week ; after death they were sold to the
College of Surgeons in Dublin, in whose mag-
nificent Museum a preparation of their skeleton
is preserved.* The writer lately received from
the President of the College of Physicians, Dr.
Croker, two hen's eggs united at their end by
a connecting stalk as thick as one's little finger,
which, in common with the two eggs, was
covered by a tough white membrane.

From intus-susception of one germ within
another, arise also some very singular pheno-
mena, such as the existence of perfect teeth set
in bony sockets, long hair, &c. in situations
far remote from those in which such structures
are naturally formed ; and the still more extra-
ordinary fact of fetuses being found within the
bodies of males ;f facts which, in the opinion
of the writer, can be explained only on the
supposition of original intus-susception of
germs, constituting that abnormal condition
which has been called monstrosity by inclu-
sion ;J an accident which appears to be by no
means confined to the germs of the mammalia
nor even of the animal kingdom. The writer
has in his museum a small egg about as large
as a gooseberry, which was found within ano-
ther egg of the common hen, which also oc-
curred to Harvey ,§ who says, " I have seen an
exceeding small egge, which had a shell of its
own, and yet was contained within another
egge, greater and fairer than it, which egge also
had a shell too. And this egge I shewed King
Charles my most gracious master in presence

* See also case by Dr. Alcock in Dublin Medical
Essays, vol. ii. p. 33, and Hall on the Czesarean
operation, p. 470.

t Med. Chir. Trans, vol. i. p. 234, case of a
fffitus found in a young man, by Nathaniel High-
more, 1815.

{ See Archives Generates de Medecine, torn. vii.
p. 355.

§ Exercitation xi. pp. 50, 51 • Ent's translation.

318

FCETUS.

of many others ; and that very year cutting up
a large lemon, I found another, small, but yet
a perfect lemon in it, which had also a yellow
rind."

Many other instances of anomalies resulting
from cohesion and intus-susception,* might be
referred to, but they will find their place with
more propriety under the article MONSTROSITY.

Mislocation of the germ during its growtli
and development is well known to be produc-
tive of serious consequences, not only to the
foetus, but unfortunately involves great danger
to the mother also, as in those instances in
which it has been developed in the ovary ,f the
Fallopian tube, the cavity of the abdomen, or
in the substance of the uterus constituting in-
terstitial pregnancy.^

Atrophy, — A very common occurrence to
the foetus in utero is atrophy, or a complete
arrest of growth from disease attacking its en-
velopes, especially the placenta or cord; in
which case, a deficient and unhealthy supply
of nutrition is furnished to the child, which
either perishes completely or has its develop-
ment retarded to such a degree, as not to pre-
sent dimensions or characters corresponding to
perhaps half the period that has really elapsed
since conception ; as happened in the follow-
ing case : a lady who menstruated in the last
week of July, began about the middle of
August to exhibit unequivocal symptoms of
pregnancy, which proceeded regularly till the
middle of October, when indications of threat-
ened abortion appeared, with pain, and the re-
peated expulsion of large coagula and sub-
stances of various appearances. After this, the
previously existing symptoms of pregnancy en-
tirely disappeared, and it was supposed that
miscarriage had occurred and that the ovum
had escaped, unnoticed, amidst the masses of
coagula. The lady resumed her ordinary habits
and went into society as usual, without expe-
riencing any uneasiness or unhealthy symptom,
except irregular uterine discharges, which were
supposed to be menstrual : so matters proceed-
ed until the 7th January, when, after a long
drive, she was seized with periodical pains ac-
companied by smart uterine haemorrhage, in
consequence of which I was sent for. I found
the os uteri open and an ovum partly protruded
through it, this I succeeded in disengaging and
bringing away ; on examination it presented
the general appearances as to size, form, and
growth of the foetus, of an ovum of less than
two months, but the placenta was as large and
as much formed as it should be at three months,
and was moreover quite unhealthy, being
throughout affected with what is usually called
the tubercular state of that organ ; the foetus
seemed perfectly healthy, but very small ; and
the umbilical cord was only about half an inch
in length, much hypertrophied, being sud-
denly enlarged on leaving the placenta, to three

* See l)ublin Journal of Medical Science, vol. iv.
p. 294, and as before note f«

t See Dub. Med. Journ. vol. ii. p. 195.

\ See a full account of this subject in Memoires
by Breschet and Geoffrov St. Hilaire ; Repertoire
Generale d'Anatomie, &c." No. 1. pp. 72, 75, 91.

or four times its natural diameter, and a^ain as
suddenly contracted almost to a thread, where
it joined the abdomen of the foetus. See sub-
joined sketch, of the natural size.

Fig. 147.

Cruveilhier * relates the particulars of a case
in which the effect of disease of the placenta in
producing atrophy of the foetus was strikingly
shewn in twins at the sixth month, one of whom
possessed the full development and characters
belonging to that period, but the other, whose
portion of the joined placentae was thin and un-
vascular, presented a size corresponding to not
more than three months, as shewn in Jig. 148.

In another case, formerly under the writer's
care, the foetus expelled at the ninth month had
only grown during the first three.f

Such cases as the above possess an interest
and a demand on our attention of a very im-
portant kind, as illustrative of the necessity for
carefully examining into the state of the foetal
appendages as to their healthy condition or
otherwise, before we venture to pronounce an
opinion on the time that has elapsed since con-
ception, merely from the size or general ap-
pearance of an ovum or foetus shewn to us ;
for here we have, in one instance, an ovum, the
size of which and that of the contained foetus,
would indicate a period of two months' preg-
nancy only, whereas jive months had really
elapsed from the time of conception, for the
parties had not cohabited since the time of the
threatened abortion ; and in the other case an
ovum of three months' growth is expelled nine
months after conception. Now, in either case,
had the husband happened to die, or to have

* Anatomic Pathologique, liv. vi. pi. vi ; see
also Graetzer, die Krankheiten des foetus, p. 83.

t See my Exposition of the Signs of Pregnancy,
&c. pp. 96, 7, and also PP. 210, 11, and 259, 60,
of same work.

FCETUS.

319

Fig. 148.

gone from home, shortly after the time of con-
ception, and the accident to have occurred in
the same way, the female might have sustained,
though most unjustly, a severe injury to her
reputation.

Hernia. — Hernia is a very frequent occur-
rence in the foetus, especially at the umbilicus,
where, in the earlier periods of foetal life, the
anterior wall of the abdomen is deficient and
the intestines covered by the expansion of the
sheath of the cord, into which they project, in
some instances considerably; of this there are
several specimens in the writer's museum ; not
unfrequently this natural deficiency remains
up to the time of birth, and congenital umbi-
lical hernia is found in the child.

In the simpler forms of this affection the her-
nial sac contains intestine only, but in other
instances which have occurred to the writer,
some of which also he has preserved, it con-
tains the liver and stomach in addition to
almost the whole tract of intestines : such ag-
gravated forms are in general connected with
other malformations, such as spina bifida, spon-
taneous amputation, &c. which combinations
are noticed under their respective heads in the
present article. In a specimen which occurred
recently in the writer's practice the liver was
protruded into the sheath of the cord, but all
the rest of the abdominal viscera were con-
tained in the natural cavity. Inguinal hernia
sometimes exists before birth, but is rare. Her-
nia cerebri is noticed elsewhere.

Diaphragmatic hernia, or protrusion of the
intestines through the diaphragm into the ca-

vity of the thorax is of rather rare occurrence,
or perhaps, more properly speaking, is less
frequently observed, because it presents no
external physical alteration of form to attract
attention.

Like umbilical hernia in the foetus, it is the
result of incomplete developement, because in
the earlier periods of foetal life the diaphragm
does not exist, and the thoracic and abdominal
cavities are one ; and as the muscle afterwards
becomes developed from its circumference to-
wards the centre, there occurs occasionally an
arrest of formation, and in consequence an
aperture is left, through which the intestines
and other abdominal viscera, as they increase
in size, pass into the cavity of the thorax, dis-
placing the heart and lungs, the latter of which
organs are thereby frequently so pressed upon
that their developement is prevented, and there
is sometimes but a very small portion of them
discoverable, especially of the one at the side
where the hernia principally exists ; which, in
a vast majority of the cases which have been
met with, has been the left, and then the heart
has been pushed over to the right side, where
its pulsations in children bom alive have some-
times given the first intimation of the existence
of the lesion under consideration. In general,
children so affected in utero have been either
still-born, or have died very soon after birth, a
consequence which it appears reasonable to
suppose results from the state of the lungs.
But in some instances the children have sur-
vived under such circumstances. Becker saw
one that lived five years; and in a case re-
corded by Diemerbroeck, where the diaphragm
was entirely absent, the child lived seven years,
annoyed only with a frequent cough. Riviere
and J. L. Petit mention instances of life much
more prolonged, in the same condition.

The writer has before him a beautiful speci-
men of this abnormal condition, for the oppor-
tunity of examining which he is indebted to
Dr. E.W. Murphy, as well as for permission
to have a drawing taken from the preparation
in his possession. (See fig. 149.)

The opening in the diaphragm in this case is
at the left side, rather anterior to and to the
left of that which naturally transmits the
oesophagus, and appears to arise in this case
from separation of the fibres of the muscle ; a
very large quantity of the small intestine is
lodged in the left side of the thorax, from
which the heart is pushed away over to the
right; the right lung, which lies behind the
heart, is natural in structure, but the left does
not equal in size half the kernel of an almond,
and does not possess the natural pulmonary
structure, but appears nearly as solid as the
liver. The stomach, spleen, and liver were in
their natural situation. The child had also a
spina bifida tumour which covered the whole
of the sacrum, and deformity of cne hand,
the thumb of which was attached by a small
pedicle to the side of the index finger. In a
case related by M. le Docteur Anthony,* which
occurred in his practice, the child, which lived

* See Journal Hebdomadaire. Fevrier, 1835.

3*20

I'CETUS.

Fig. 149.

Diaphragmatic Hernia.

a. The heart, b, b. The intestines which had
passed through the diaphragm and occupy the left
side of the thorax, displacing the heart, c, c. Por-
tions of intestine below the diaphragm, d. The
stomach, e. The liver.

half an hour, had no external appearance of
any thing abnormal ; but, on examination after
death, the left side of the diaphragm was
found not to exist, and the small intestines
and spleen were contained in the thorax ; in all
other respects the condition of the child exactly
resembled that described above.*

Hernia cerebri or encephalocele. — The af-
fection to which these names are applied is not
of unfrequent occurrence in the foetus. It con-
sists of a tumour protruding from the cavity of
the cranium through an aperture in the bony
structure, covered externally by the integuments,
lined internally by the dura mater and arach-
noid, and containing portions of the cerebrum
or cerebellum, together with serous fluid, with
which the cerebral structure is in general infil-
trated and softened down ; sometimes the con-
tents of the tumour appear to be completely
fluid.

This affection is most frequently situated on
some point of the central line of the head,
commencing at the root of the nose and ter-
minating at the foramen magnum of the occi-
pital bone ; these being the situations in which
the foetal head, during a considerable period,
consists only of membrane; the writer has seen
it in the centre of the forehead at the anterior
and posterior fontanelle and in the centre of
the occipital bone. According to the observa-
tions of Mr. Adams,t the tumour is most fre-
quently situated at some point in the middle
line of the proper occipital portion of the os

* For other instances of this affection, see Ar-
chives Generates, torn. vii. p. 142. Transactions
Medicales, torn. xii. p. 359.

t See an excellent paper by him in the Dublin
Medical Journal, vol. ii. p. 321.

occipitis, as in Dr. Collins's case, to be noticed
presently ; but it has happened to the writer to
observe it more frequently in the other situa-
tions above mentioned. In one of the cases
related by Mr. Adams, it occurred just over
the right eye, and the subject of it had reached
his twentieth year when the account of his case
was published. (See/g. 150.)

Fig. 150.

In such instances the bony vault of the head
is usually much smaller than in ordinary cases,
being proportioned to the diminished quantity
of its contents, and the sutures and fontanelles
are found closed.

In the first case of this affection which came
under the writer's notice, a tumour, about the
size and somewhat of the shape of a fresh fig,
hung from the centre of the child's forehead
down over the face ; it was only partially filled,
and apparently with a gelatinous fluid ; when
compressed towards the forehead the contents
were diminished, but, in the same proportion,
the child appeared distressed, and the features
began to be distorted, the vault of the cra-
nium was in a great measure deficient of its
proper developement, the parietal and frontal
bones rising very little above the base of the
cranium, when they turned over to form the
roof of the skull. The child did not present
any other external deviation in form ; it lived
ten days, taking food, digesting, and perform-
ing the other common functions like other chil-
dren, but then pined away and died. On exa-
mination after death, it was found that the
bag which had protruded and hung over the
face was lined by the dura mater and arachnoid,
that the cerebrum was entirely absent, as was
also part of one side of the cerebellum ; the
aperture in the frontal bone, through which the
hernia passed, was situated just over the root
of the nose, in the line of 'the suture, was about
three-sixteenths of an inch in diameter, and
with smoothly rounded edges; the sutures and
fontanelles were quite closed up. M. Moreau,

F(ETUS.

not long since, presented a nearly similar case
to the Academy of Surgery at Paris.

In another case, the cast of which was sent
to the writer by Dr. Gason of Enniskerry, the
hernia appears to have taken place at the ante-
rior forxtanelle. J. Cloquet met with a case
where it protruded through the posterior fonta-
nelle.* A remarkable case of this affection,
occurring in a very unusual situation, was ob-
served at the Hotel Dieu at Paris : a child of
about a year and a half old was admitted on
account of a small tumour, supposed to be a
ganglion, about as large as a nut, and situated
at the root of the nose, exactly under the nasal
process of the frontal bone. At birth it had
been only as large as a pea ; it was increased in
size, and became redder when the child cried;
the child was very irritable; pressure on the
tumour gave pain, and produced a general
agitation. Dupuytren suspected that the tu-
mour was formed by a prolongation of the
brain through some congenital opening in the
base of the skull, and on consulting with M.
Breschet, the latter declared that he had met
with a precisely similar case, in which, on
dissection, he had found that the tumour was
formed by a portion of one of the anterior lobes
of the brain, which was prolonged through a
slit in the centre of the ethmoid and sphenoid
bones down to the root of the nose.t

As tumours of a very different character
are frequently observed on the foetal head at
birth, it is of consequence to be satisfied of
the diagnostic characters of the encephalocele,
which is at first a rather tense, smooth, and
semitransparent tumour, giving generally a
more or less distinct sense of fluctuation; it
afterwards collapses and becomes wrinkled and
smaller in dimension ; the integument over it
is thin but not discoloured, not unfrequently
pale : in shape the tumour is globular or oval,
and frequently tapers to a neck where it issues
from the head, (see Jig. 151,) at which point a
circular aperture can be detected in the bone,
the edges of which are in general smoothly
rounded off; the tumour is not painful, but, if
it be compressed by the hand, so as to cause a

Fig. 151.

* Diet, de Med. torn. viii. p. 52.
+ La Lancette Fransaise, Mars, 1835.
VOL. II.

considerable diminution in its volume, the child
appears to suffer much distress, sometimes
has the features slightly convulsed for the mo-
ment, and is rendered stupid and paralytic, as
under other circumstances of cerebral oppres-
sion; pulsations are to be felt in the tumour
synchronous with those of the heart; and,
lastly, the volume of the tumour is suddenly
increased by any effort on the part of the child,
as by coughing, straining, crying, &c.

Most children so affected are either still-
bora or live but a very short time; to this,
however, there are exceptions; one has already
been mentioned, another has been related on
the same authority,* and Guyenot brought
before the Royal Academy of Surgery in 1774,
a man of thirty-three years of age, with ence-
phalocele in the forehead, who had never ex-
perienced any disturbance of his intellectual
faculties. Lallemand attempted to remove a
tumour from the occipital region of a young
woman of twenty-three, under the idea that it
was a wen ; but unfortunately, on attempting
to operate, he found that it was an encephalo-
cele; inflammation ensued, and the patient
died.

Spina bijida. — An affection in many respects
analogous to that just described to which the
foetus is liable, is that which has received the
name of spina bifida, and consists of a tumour
situated on some part of the spinal column,
most frequently over the lumbar vertebrae, but
it may be found at any point along the whole
length of that column. The writer lately saw a
case of it in which the tumour was situated so
high on the cervical vertebrae, that it was diffi-
cult to determine whether it arose there, or from
the base of the occipital bone. A similar case
is recorded by Dr. Collins, in which a child
was born with a tumour projecting from the
back of the head nearly as large as the head
itself; it burst, and the child died in ten hours:
" The tumour to a considerable extent was
covered with hair, the remainder being bare
skin of a thin texture, with a blueish tinge ;
with the exception of one spot the size of a
shilling, which had almost the appearance of
serous membrane.

" The ventricles of the brain were much dila-
ted and communicated freely with the sac. The
membranes were extremely vascular, and the
whole contents of the cranium in a dark con-
gested state. The opening through which the
tumour had formed was about three-eighths of
an inch in diameter, and half an inch behind
the foramen magnum. The bones of the head
generally were very imperfect as to ossifi-
cation.'^

The most unusual form of it is that in which
the tumour appears at the very extremity of the
sacrum, where it joins the coccyx. Ruysch,
however, met with an instance of the kind, and
Genga with another, in which there was also
hydrocephalus, the fluid of which was eva-
cuated by opening the tumour on the spine.}

* Loc. jam cit. p. 341.

t Practical Treatise on Midwifery, p. 511.

$ Vide Morgagni, epist. xii. art. 9.

322

FCETUS.

A case occurred not long since in this city,
under the observation of Dr. Murphy, in which
at the time of the birth of the child, which
presented the breech, a membranous bag
protruded before it, and was supposed at the
moment to be the membranes of the ovum,
but it was found to be the covering of a spina
bifida tumour, over which the integuments were
deficient: it was of considerable size, nearly
equalling that of the child's head, and sprung
from the very lowest point of the sacrum, as
represented in the subjoined sketch : —

In another instance, for the observation of
which the writer is also indebted to Dr. Mur-
phy, the tumour occupied the whole length of
the sacrum, and was conjoined with diaphrag-
matic hernia. In some rare instances there have
been more than one tumour : in size these
tumours vary from the volume of a small nut
to that of a child's head at birth ; and in their
form there is also considerable variety, some
being very exactly globular, while others are of
the long oval, some pyriform with the tapering
pedicle next the spine, and others broader in
that situation than externally, and so rather
representing the form of a cone. As a general
description of the affection, its pathological
anatomy is this : there is a deficiency in the
posterior arch of one or more vertebrae, arising
either from imperfect development of these bones,
or their division ; through the opening thus
caused, protrudes a sac consisting of the in-
vesting membrane of the spinal marrow, which
sac is in general covered externally by the
common integuments, which are sometimes in
a healthy state, but more frequently diseased,
being sometimes extremely attenuated, either
wholly or partially and sometimes in a state of
ulceration, or approaching to a state of gangrene;
occasionally the integuments are altogether ab-
sent, and the membranes form the covering of
the tumour ; the contents are a fluid of various
characters in different cases ; appearing some-
times bloody, puriform, and otherwise con-

taminated, but when presenting its more natural
serous condition, it is found, like that of hy-
drocephalus, to contain a smaller proportion of
albumen than the fluid of other dropsies.
Sometimes the fluid contained in the tumour
can be made, merely by pressure on the latter,
to retreat and pass along the spinal canal into
the ventricles of the brain, producing the sym-
ptoms of cerebral compression ; and in such
cases also, as in encephalocele, efforts, as of
crying, coughing, &c. produce an immediate
increase in the size of the tumour : and in the
case mentioned by Morgagni, the enlargement
of the head from hydrocephalus was diminished,
when the spina bifida tumour was opened and
its contents allowed to flow out.*

Spina bifida has been found engaging the
whole length of the spinal column, which
is, however, very rare, and sometimes it has
passed, not through a divided or imperfect
vertebra, but through a space accidentally ex-
isting between the last lumbar vertebra and the
first piece of the sacrum. f

This affection of the foetus, though some-
times found unaccompanied by any other, is in
many instances complicated with morbid lesions
of an important kind, such as hydrocephalus,
malformation of the lower extremities, which
are apt to be curved inwards, or otherwise
distorted, deficiency in the coverings of the
abdomen, and umbilical hernia, hare-lip, &c. :
in one instance in the writer's museum, in
which there was adhesion between the foetus
and the amnion, spina bifida is accompanied by
malformation of the lower limbs, and an enor-
mous umbilical hernia, in which are contained
almost all the abdominal viscera.J (See Jig.
153.)

Fig. 153.

b, a membranous pouch, which contained the
abdominal viscera during uterine existence.

d, the placenta and its membranes.

e, the liver, f, intestines.

g, external opening of vagina.
h, an aperture in the situation of the meatus
urinarius.

/, spina bifida tumour.

* Epist. xii. art. 9.

t Andral, Mohrenheim, Portal.

$ [Some time ago the Editor was favoured by his
friend Mr. Hale Thomson, Surgeon to the West-
minster Hospital, with an opportunity of examining
a remarkable case of double spina bifida. There

FCETUS.

323

The spinal marrow is sometimes healthy,
but more frequently it is morbidly affected and
sometimes deficient ; it is sometimes displaced
from the spinal canal and lodged in the cavity
of the tumour, especially when the latter occurs
over the lumbar vertebrae ; sometimes the cauda
equina has been contained in the tumour, and
its component nerves found separated and
floating in the fluid, or spread over the walls of
the tumour.

Children thus affected seldom survive, what-
ever treatment may be adopted ; some rare
exceptions have, however, been met with, in
which life has been continued even up to
adult age; as in the case related by Mr.
Jukes,* in which the woman had arrived at the
age of twenty at the time of writing the ac-
count; the tumour, which had been at birth
about the size of a pigeon's egg, had acquired
dimensions much greater than those of the
head ; after birth, the limbs, which had been
well formed, became in a few years curved
inwards, and the woman was gradually reduced
to a most miserable condition. A similar case
of survival to the age of twenty is mentioned
by Warner. f

A case has been recently recorded in which
an enormous tumour of this kind delayed the
delivery of the body of the child for two hours
after the birth of the head, which it equalled
in size, extending from the third cervical verte-
bra to the eighth rib, and containing a quart of
fluid, which communicated with the ventricles
of the brain 4

were two tumours, the lower one of very consider-
able size, and on its posterior wall constricted
along the mesial line ; this tumour occupied the
whole sacral region. It was distended by a clear
straw-coloured fluid ; and an imperfect septum,
corresponding in situation to the constriction already
mentioned, projected into its cavity. The second
tumour was in the lumbar region, and seemed to
be a hernia of the spinal meninges, occasioned by
a deficiency in the laminae on one side of only two
lumbar vertebra ; it was consequently small, and
communicated with the canal by a narrow neck.
The lining membrane of this tumour was over-
spread by an intricate plexiform arrangement of
nerves. In this case there were several malforma-
tions ; one ankle-joint was in a state of luxation
occasioned by the non-developement of the articular
extremities of the bones. The intestinal canal was
very imperfect, the small intestine composed of a
very few coils, and only the coecal extremity of the
large existing, which opened on the pubic region
of the abdominal parietes. The bladder was absent,
each ureter terminating in a small sac, which
opened on either side of the misplaced anus just
mentioned. For a space about an inch and a half
in diameter, immediately around where the ureters
and intestine opened, the skin of the abdomen was
raw, very red, and resembled greatly the exposed
mucous membrane of the bladder in cases of
extrophy of that viscus. The left kidney had its
hilus directed outwards instead of towards the
spine ; the ureter consequently turned in behind
the kidney in order to reach its destination. The
uterus and vagina were natural. This case has
already been alluded to in a note at page 390, vol. i.
of this work. ED.]
* See Lond. Med. and Phys. Journ. vol. xlvii.

t Cases in Surgery, 4th edit. p. 134.
t See Lancet, No. 261, p. 698.

Cranial tumours. — It has been already sug-
gested that there were other tumours observable
on the head of the child at birth of a totally
different character from the encephalocele, but
which might be mistaken for it ; an error into
which it is said that the celebrated Ledran fell :
these tumours are generally the result of pres-
sure during labour, producing ecchymosis and
sometimes bloody effusion between the scalp
and the cranial bones ; they differ in all respects
from the encephalocele ; they are darker co-
loured, without any pulsation, situated over
the solid part of the bones, especially over the
parietal of one or other side ; they cannot be
diminished at the instant by pressure, nor does
pressure cause the internal distress which results
from it when applied to the hernia cerebri ; and
lastly, no opening can be ascertained in the
bone; but with regard to this last point of
diagnosis, I wish to direct attention to a cir-
cumstance calculated to embarrass the examiner
and lead him into error; in examining tumours
of this kind, it is not unusual to find around
their base a defined and slightly elevated cir-
cular margin, which at first one would be al-
most certain was the circumference of an aper-
ture in the bone, but on further examination it
will be found, that if the point of the finger be
pressed within this circular margin, it will
there meet with as decided and firm a resistance
as it did outside of the base of the tumour. I
have known this peculiarity lead to the pro-
nouncing of a very erroneous opinion as to the
nature and prognosis of such a tumour.

These tumours have been found to contain
bloody serum, or pure blood, either fluid or
coagulated, and sometimes both ; the effusion
takes place either between the bone and the
pericranium, or external to the latter and
under the integuments : the former variety has
been called cephalaematome by Naegele,* who,
as well as Schmitt, has given an account of it.

Having stated that these bloody tumours are
generally the result of pressure during labour,
I should add that I have reason to believe that
they are formed occasionally quite indepen-
dently of any such cause. I very lately at-
tended a patient who gave birth to a child
which had hardly arrived at seven months, with
an easy and expeditious labour, yet the infant
had a very large tumour covering the greater
part of the right parietal bone, having all the
characters of the cephalaematome, and was not
removed till the termination of a month.

Injuries of the cranial bones. — The same
causes which give rise to the formation
of the bloody tumours just described, not
unfrequently produce fractures or depres-
sions of the flat bones of the cranium, espe-
cially of the parietals ; more particularly in
cases of contracted pelvis, where the promon-
tory of the sacrum projects considerably in-
wards ; though I have known such accidents
happen without the concurrence of any such
state of the pelvis, but from the interposition
of an arm between the head and the bony wall

* Zeller, Comment, de Cephalematomate, &e.
Heidelberg, 1822.

Y 2

324

FCETUS.

of the pelvis : in one case where the labour
required version of the child, the arm got be-
tween the side of the head and the pubes and
produced so much difficulty in the delivery,
that the left parietal bone was completely
depressed. Siebold has reported a case in his
journal, in which the labour was painful and
tedious, and the child was born dead : a large
bloody tumour was found over the right parietal
bone ; and on exposing the bone, it was tra-
versed by three distinct fissures passing in
different directions : no instruments had been
used.* But I have reason to know that these
injuries of the cranial bones may occur, not
only independently of contracted pelvis, but
even of slow or difficult labour. I some time
since attended a lady in her second labour, and
after about three hours from its commencement,
she gave birth to a healthy boy, but with a
depression in the left temporal bone which
would readily have contained an almond in its
shell ; by degrees the depression disappeared,
and at the end of a few months no trace of it
remained ; the lady's first labour was easy, as
were also those that succeeded the birth of this
child, and no such injury was observable in
any other of the children. More recently I
was informed by Mr. Mulock, of a case in
which, on the subsidence of a cranial tumour,
a spicula of bone was felt distinctly projecting
under the integuments; the labour had been
slow but natural. When these injuries of the
foetal head were first observed, they were attri-
buted to violence by Haller, Rosa, and others,
the error of which opinion was first perceived
by Rcederer and Baudelocque, and it is need-
less to say how important is the distinction,
especially in a medico-legal point of view.

Fractures of the long bones have been ob-
served sometimes as the result of injuries
sustained by the mother, but in other instances
independent of any such cause, and apparently
depending on some defect in their composition.
I saw an instance in which a woman, when
eight months pregnant, was precipitated from
the second slory of a house into the street, by
which the hip-joint was dislocated, and she was
otherwise much injured; she fell on her face,
yet the uterus was not ruptured ; labour came
on that night, and the child was born dead
with several of its bones broken : the woman
recovered well. A case is quoted by Duges on
the authority of Carus, in which a woman fell
on her belly and caused a fracture in the leg of
the child, which was born with the fracture
complicated with wounds in the soft parts ;
gangrene supervened and detached entirely the
fractured limb.f MarcJ relates a case, in
which all the bones of the limbs and several
others were found fractured, the mother not
having met with any accident, and having had
an easy and quick labour ; the child was born
alive and lived for some days : on examination
after death the number of fractures were found

* See Med. Chir. Review, No. 37, July 1833,
p. 211.

t Diet, de Med. et de Chirurgie Prat. torn. viii.
p. 293.

J Diet, dee Sc. Med. torn. xvi. p. 63.

to amount to forty-three, some of them just
beginning to unite, and others almost com-
pletely consolidated.

In a case which occurred to Chaussier, in
which also the labour was quick and easy, and
the mother had not sustained any previous acci-
dent, the child was born alive and survived
twenty-four hours ; its limbs were malformed,
and after death no less than one hundred and
thirteen fractures were discovered in different
conditions, some of them being already quite
consolidated, while others were apparently
quite recent.*

Fractures independent of any external injury
or defect of nutrition are supposed by some to
be produced by violent spasmodic contractions
of the foetal muscles, which are capable of very
energetic efforts, at a time when the foetal bones
have very little power of resistance. It appears
reasonable to believe, that such spasmodic
action of the muscles might be induced by
causes violently disturbing the nervous system
of the mother, since we know that such in-
fluences acting on a nurse will cause spasmodic
and convulsive affections in the child at her
breast ; and we further know, that even in the
adult a quick muscular effort has been followed
by fracture of a bone, but how far such analo-
gies are applicable to explain the lesion in
question I would not pretend to determine.

A similar explanation has been supposed
applicable to the instances of dislocations which
have been discovered in the foetus, and one in
particular related by Chaussier appears to
correspond to such a supposition. A young,
delicate, and nervous lady, in the ninth month
of pregnancy, suddenly felt such violent and
rapid movements of the child that she was near
fainting; these tumultuous motions were three
times repeated in the course of ten minutes,
and then there succeeded a perfect calm ; the
remainder of the pregnancy passed on well,
the labour was easy, the child was pale and
weak, and had a complete dislocation of the
left fore-arm .f In another instance mentioned
by MarcJ there were found, in addition to
congenital dislocation of both hip-joints, no
less than seven other luxations.

But by far the most remarkable pathological
lesion to which the foetus in utero is subject, is
that in which portions of its limbs are removed
by a process which has been with propriety
denominated spontaneous amputation.

This singular fact has been mentioned by
several authors of credit, as Richerand,§ Desor-
raeaux,|| Billard,^ and Murat,** though none
of them appear to have witnessed any case of
the kind themselves; but they all agree in

* For a full account of the dissection, see
Bullet, de la Fac. de la Soc. de Med. de Paris,
1813, No. 3.

t Discours prononce a la Maternite, Juin 1812.

J Diet, des Sci. Med. t. xvi. p. 66. See also
une Memoire sur un deplacement originel ou con-
genital de la tete des femurs, par M. le Baron Du-
puytren; Repertoire d'Anatomie, t. ii. partie 1.

§ Elemens de Physiologic, p. 477.

\\ Diet, de Med. t. xv. p. 404.

1 Maladies des Enfans, p. 623.

** Diet, dea Sci. Med. t. xvi. p. 70.

FCETUS.

325

regarding it as simply the result of inflamma-
tion and gangrene. Haller evidently was not
aware of any such case, for although he gives
a long list of extraordinary mutilations of the
foetus, he considers them as the result of im-
perfect development or malformation, and not
of separation or removal exports already formed;
for he expressly objects to the authors who have
furnished such descriptions, that they cannot
even quote one instance in which " manus
truncata, aliusve artus, in membranis foetus
seorsim a corpore, repertus sit."* Having
sought with diligence through authors, the only
cases which I have been able to find are those
which I shall now briefly mention.

In the 54th volume of the Lond. Med.
Phys. Journ. Mr. Watkinson states, that being
in attendance on a lady twenty years of age in
her first labour, which was natural and easy,
he discovered, on the birth of the child, that
the left foot had been amputated a little above
the ankle, and the part was nearly but not
quite healed, the bones protruding a little.
The child was alive, but survived only a few
minutes ; on making further search the ampu-
tated foot was found in utero, and it, also, was
nearly healed. There did not appear to have
been any haemorrhage from the limb ; the sepa-
rated foot was much smaller than the other; it
shewed no mark of putrefaction, but appeared
to be in a state of perfect preservation, not
being even discoloured. The mother had not
met with any accident nor any particular mental
emotion, and she was sufficiently independent
to render unnecessary any over-exertion on her
part. Mr. Watkinson offers no opinion on the
nature or cause of the accident. The annexed
sketch represents the condition of the parts.

Fig. 154.

Chaussierf mentions having examined two
cases in which separation of a part of the fore-
arm had taken place before birth, and in a
third case he found the separated portion of the
arm and hand lying apart, and the stump of the
limb healed.

Chaussier also attributes the accident to gan-
grene as the cause which would most obviously
account for its production, though it does not
appear from his account that there were present
any of the pathological evidences of that con-
dition ; and in the case first related the child
was born alive, and it is expressly mentioned
that neither the stump of the limb nor the part
amputated shewed any symptom of disorganiza-
tion or disease, not being even discoloured.

The next case was one occurring in my own
practice, and appears to me of great importance
as exhibiting the amputation absolutely in pro-
gress, under the influence of the agent which
I believe to be the general, and, most probably,
the invariable cause of its occurrence.

About eight years since I attended a patient
under circumstances of considerable danger
from haemorrhage attending abortion in the fifth
month, and on the expulsion of the foetus its
singular conformation fortunately attracted my
attention strongly, and induced me to examine
it with care. The head was mis-shapen and
monstrous, the brain covered only by integu-
ment, and towering upwards like a helmet
over the head ; but the circumstance deserving
of especial notice was the appearance of com-
plete ligaments surrounding the limbs, and on
examining them closely I found that they con-
sisted of distinct threads, passingfrom both hands
downwards to the legs (see/g. 155) ; at one end,

Fig. 155.

* Elementa Physiologiae, t. viii. p. 1!
t Discours prononce a 1'Hospice de la
1812.

135.

Maternitc,

each of these threads or fine cords had formed
a complete ligature round the middle of each
hand, causing a distinct depression where it
passed, the part of the hand below it being
almost completely undeveloped. From the
hands these cords descended towards the legs,
which were crossed, and surrounding them "in
this position just above the ankles, compressed
them so tightly that fully two-thirds of their
whole thickness were thereby divided, without,
however, causing any breach in the skin; nor

326

FCETUS.

was there the slightest appearance of disease
or even discolouration of any of the parts, but
the feet were, like the hands, imperfectly deve-
loped and mis-shapen. The mother was about
twenty-five years of age, and was at the time
labouring under fever, but had been previously
in perfectly good health, and had not met with
any accident either in the way of bodily injury
or mental agitation.

About four years after the occurrence of the
case just detailed, another was brought under
my observation through the kindness of Dr. J.
Labatt.

A healthy woman gave birth to a still-born
child in the eighth month of gestation ; it was
affected with an umbilical hernia of great size,
formed by the protrusion of the liver, stomach,
and small intestines, but the state of the limbs
is the point of interest connected with our
inquiry: both were mis-shapen, and, as hap-
pened in Mr. Watkinson's case, the left exhibits
this remarkable pathological lesion, and exactly
hi the same situation. Just above the ankle
there is a deep depression all around the limb,
and sinking to such a depth as to leave only
the bones and skin unaffected by it, the
diameter of the undivided part being less than
half an inch, while that of the leg, just above
the depression, is an inch and a quarter. The
appearance of the groove is exactly such as
would be made by tying a string very tight
round the plump limb of a child, and in my
opinion could not have been produced in any
other way. The part had been very much
handled and examined by several before I saw
it, so that I was not surprised at not finding
any ligature on the limb, but the mark of it
was so distinct in the bottom of the depression
as to leave no doubt of its previous existence
there having produced the constriction of the
part. It is important also to observe, as con-

Fig. 156.

firmatory of this view of this matter, that the
integuments are not at all broken or divided,
but are merely carried inwards with the con-
stricting agent, so that, had the separation of
the limb been completed, each stump would
appear skinned over, except at the ends of the
bones, and so present the appearance of being
partially healed, as described by both Watkin-

son and Chaussier: the foot was a little swollen
and somewhat discoloured; it seemed turgid
with blood, but was without any appearance
whatever of gangrene.

In both the instances here before us, from
the condition of the limbs and the impossibility
of the parts under the ligatures continuing their
growth under such circumstances, it could
scarcely be made subject of doubt that had the
children continued to live and grow, the parts
of the limbs below the constriction would have
separated, and so undergone spontaneous am-
putation.

The next case to which my attention was
drawn was one very politely communicated to
me by Dr. Tyson West, of Alford, Lincolnshire,
in consequence of his becoming acquainted
with my account of this matter. Dr. West
attended a patient at the Westminster Lying-in
Hospital in 1805, who, after a natural and
easy labour, gave birth to a still-born child
which had but one leg, the other limb exhibit-
ing positive proof of having been spontaneously
amputated some time before, the stump being
partially healed and nicdy rounded, about an
inch and a half below the knee : the unhealed
portion of the stump was about this size.
He accounts for the amputated portion
of the limb not being found in conse-
quence of the occurrence of a m
dangerous accident which threw all the parties
concerned into great alarm and confusion ; but
he adds that it struck him at the time, and he
is still of the same opinion, that the division
of the limb was effected by some stricture
round it*

When first announcing the discovery of this
fact, in 1832,f I stated that the origin of these
ligatures, and still more their application so as
to stricture the limbs, were circumstances on
which I did not feel prepared to pronounce
an opinion with any reasonable probability of
its being satisfactory, and I am sorry that five
years' additional consideration of the matter has
not enabled me to solve the difficulty com-
pletely; but I am happy to find that, so
far as I have ventured to point out a proximate
cause of this singular phenomenon, my views
have been assented to, and my explanation
adopted, by all who have subsequently ex-
pressed their opinions on the subject, and
especially by Professor Gurlt, of the Royal
School of Medicine at Berlin, author of a
work on pathological anatomy, (whose investi-
gations render him peculiarly qualified to form
an opinion on such a subject,) who has written
a commentary on my original paper,J in which
he adopts, as correct, my explanation of this
curious fact, and, in addition, undertakes to
account for the formation and application of
the ligatures.

He commences his observations by rejecting
in toto the notion of the agency of gangrene :
his words are : " To explain this most re-

* A notice of this case was inserted by Dr. West
in the Lond. Med. and Surg. Journ. for 1832, vol. i.
p. 741.

t See Dublin Medical Journal, vol. i. p. 140.

f See Mediciuische Zeitnng, 1833, N. 3, p. 13.

FCETUS.

327

markable phenomenon, the utterly unfounded
hypothesis has been formed, that these spon-
taneous separations are the result of gangrene,
although there are no traces of it to be dis-
covered on the stump, it being actually, to
a certain extent, healed, and no change of
colour to be seen :" and he immediately adds,
" a case lately observed by Montgomery of
Dublin appears to contribute a natural explana-
tion of this remarkable fact, inasmuch as it
indicates the cause of this separation." He
then repeats the details of my first case, and
proceeds to say he " believes that both the
formation of these threads, and the amputation
of the limbs, which are most probably in all
cases produced by them, may be explained
by the history of the formation of the fetus."
He then enters into a minute detail of facts
well known to all who are acquainted with
the mode in which the development of the
fetus takes place, and observes, " I look upon
these threads as prolongations of the egg mem-
brane from which the foetus grows, whether
this skin (or membrane) be taken as the navel
bladder or the amnion :" and he subsequently
objects to their being considered as formed by
organized lymph, which I considered them
to be, and still remain of the same opinion.

The prolongations of the membrane, Gurlt
thinks, are afterwards, by the constant motions
of the fetus, twisted into slight but firm cords
or threads, which may involve different portions
of the fetal limbs, (as we sometimes find the
umbilical cord several times round the neck,
or other parts of the child's body,) so as to
stricture them and cause their separation ; and
in this way Professor Gurlt explains the
presence of the ligatures concerned in the pro-
duction of spontaneous amputation. I dissent
from this as a general explanation, for a reason
presently to be stated ; but it is only justice
to the author to mention that the condition
of both the children which I examined was
in other respects such as favours his theory,
for whenever such unnatural adhesions take
place between the amnion and the fetus, they
give rise to a monstrosity of a peculiar kind,
and this is observable in both these cases, and
in others also : in one there is protrusion of
the brain and monstrous formation of the head
in other respects ; and in the other the liver,
stomach, and great part of the intestines were
contained in a hernial sac, external to the body.
But notwithstanding the support thus derived
from analogy, there is one circumstance which
appears fatal to the explanation when applied
to the first case described by me, which is,
that in all cases where these membranous con-
nections have been observed giving rise to
monstrosity, one end of the cord or thread-
like band has always been found attached to
the amnion, and the other to the fetus, but
here both ends of the cords are attached to
the limbs, and afford no evidence of having
been connected with the amnion ; and it was
for this reason that I abstained at first from
offering the explanation now proposed by Pro-
fessor Gurlt, which I then thought, and still
consider inapplicable to the specimen which

I was then describing, and equally, or perhaps
still more so, to that described by Zagorsky,
to be mentioned presently, seefg. 159 ; though,
at the same time, I am quite ready to admit
that ligamentous bands so formed would be
fully adequate to the accomplishment of such
an effect : and I now know also that strictures
from another source, and which from their
nature must possess very little constricting
force indeed, are in some instances found
sufficient so completely to act on and indent
the limb, that, could their action be con-
tinued, which, however, is scarcely possible,
they might ultimately induce a similar mutila-
tion. While I was engaged in committing
these observations to writing, I received a most
interesting preparation from Dr. W. O'B.
Adams, in which the coiling of the umbilical
cord round the left leg of the fetus at three
months had deeply indented it, as represented
in the subjoined Jig. 157. Here, it will be

Fig. 157.

observed, at least three-fourths of the thick-
ness of the limb are divided by the pressure
of the umbilical cord, which was coiled around
it, and which, both in this and fg. 158, is
removed from the strictured part where it
originally lay, in order to show more distinctly
the effect produced by it.

Within the last few months another instance
of the same effect produced by the same agent
just above the left knee of a fetus at about
the same period of growth, occurred with a
patient of the writer's, and under his imme-

328 Fd

diate observation, as shewn in the annexed
fgure, 158.

FCETUS.

Fig. 158.

J am very much disposed to believe that
Morgagni witnessed a fact of this kind; at
least his description of the appearance in a
monstrous fetus between the fifth and sixth
month, greatly resembles it, of which he says,
" All the limbs were in a very bad state, the
upper limbs from the elbows downwards ;
for to the arms, which were very short and
distorted, distorted hands were likewise added.
And the inferior limbs terminated, likewise, in
distorted feet, but the left leg was either broken
from the funiculus umbilicalis having been ap-
plied round it, or was more distorted than
the other parts:"* and he afterwards, with
great reason, conjectures that the binding of
the cord round the leg may have been the
cause of the child's death, by interrupting
the circulation through it. It is a very ex-
traordinary fact, that in every one of these
cases, as well as in several others, the injury
was sustained by the left extremity.^

In the course of the last year Dr. Simpson
of Edinburgh published an excellent paper on
this subject;]; into which he has collected a
vast quantity of curious information and many
most important cases from authors, to which

* Epistle xlviii. art. 53, vol. ii. p. 758, of
Alexander's translation.

t For other instances of impressions made on
the fcetal limbs, &c. see Van de Laar, Obs. Obstet.
Mecl. p. 41, and tab. 11 ; Meckel, Patholog. Anat.
Bd. ii. s. 137; Sandifort, Thesaurus, torn. iii.
p. 235, tab. 11, fig. 5.

| See Dublin Medical Journal for November.
1836, vol. x. p. 220.

he has added not a few from his own obser-
vation, together with several highly apposite
remarks ; and I am happy to find that he also
assents to, and, indeed, strongly confirms my
view both as to the agent which produces the
change and its consisting of organized lymph,
such as is usually elaborated under the influence
of inflammatory action, from which it is well
known that several varieties of fetal deformities
arise;* and it is a matter of every day ob-
servation how completely lymph so effused
will be converted into distinct firm threads,
uniting opposite serous surfaces, especially
those which move freely on each other, as the
pleurae and the peritoneal coverings of the ab-
dominal viscera.f

From the cases referred to by Dr. Simpson,
I shall now notice three which appear more
particularly illustrative of the true nature of
this remarkable lesion, and confirmatory of my
original account of it.

Zagorsky has described J a malformed fetus
of the fifth month, which, in addition to several
other deformities, was deficient of the right
leg, the thigh ending in a rounded and cicatrized
stump, in the centre of which was a small
projecting point: from this was prolonged a
slender thread-like membrane, strong in pro-
portion to its size, that ran directly across to
the left leg, which it encircled, a little above
the ankle, like a tightened ligature, see^g. 159,
and formed in it a depression of considerable
depth, while the portion of the extremity
below the ligature was, as well as the appended
foot, rather tumefied. From about the middle
of the transverse thread-like membrane a small
body of an oblong form was suspended, which,
on examination, proved to be the right foot
perfectly formed, as its general outline and
five toes demonstrated, but not larger in size
than the foot of a fetus of the tenth or twelfth
week.

Beclard mentions § the case of a very de-
formed hydrocephalic fetus, whose left leg was
divided by a transverse depression that pene-
trated as deep as the bones, and resembled that
which would have been produced by a tight
ligature. The two opposite surfaces of this
indentation were both cicatrized, and almost
touching one another. " It is evident," says
Beclard, " that if this fetus had remained in
utero for some time longer, it would have been
born with an amputated and cicatrized leg, the
remains of which might have been found in the
liquor amnii."

* See Geoffrey St. Hilaire's investigations in his
work on " Monstruosites Humaines;" Meckel's
Handbuch der Pathologischen Anatomic, Bd. ii.
s. 138; and a paper on the diseases of the placenta,
by Dr. Simpson, in the Edin. Med. and Surg.
Journ. vol. xlv. p. 305 et seq.

t Dr. Hildebrand of Berlin has also noticed my
cases with some remarks : see Grafe, und Walthers
Journal der Chirurgie, Bd. 18, 11, p. 325 : 1832.
The latest author on the subject is Graetzer, die
Krankheiten des foetus, Breslau, 1837, p. 69.

\ Memoirs of the Imperial Academy of Sciences
of St. Petersburgh for 1834, sixth scries, vol. iii.
p. 3, 7.

§ Bulletins de la Faculte, &c. for 1817, torn. v.
p. 213.

FOETUS.

329

Fig. 159.

Albert F. Veiel quotes a case from Froriep's
Notizen, Bd.xii. p. 26, of a foetus " whose left
foot was separated, during pregnancy, from
"the bone, and the fore foot was born by itself,
quite healed."*

The following case was recently published in
the American Journal of Medical Science, by
Dr. F. P. Fitch of New Boston. On the 17th
March a healthy woman, then in the seventh
month of pregnancy, suddenly discharged the
liquor amnii. On the 21st a substance escaped
from the vagina, which proved to be a perfectly
well-formed fioetal foot, apparently separated at
the ankle-joint, and in a complete state of pre-
servation. On the oth April she was delivered
of a seven-months' child, which lived about
half an hour. At the left side of the centre of
the forehead there was a horny protuberance of
the size of the middle finger ; the face, also,
was greatly deformed. Upon the foot, the
place of separation was contracted to the size
of a small pin's head, and the healing process
had apparently been as perfect, and progressed
very nearly as far as that on the lower extre-
mity of the limb.\

Within the last few months a child of a
month old was brought to me from the county
of Westmeath, in consequence of its having
been born deprived of the left hand. On exa-
mination I found the forearm of that side pre-
senting, a little above the wrist, the appearance
of a perfectly well-formed stump, as it would
be -found after amputation by the surgeon's
knife; with this difference, however, that the
mark of cicatrix did not extend across the
stump, but was confined to a small circular

* " Der linke Fuss wahrend der Schwangerschaft
sich von dem Beine ablbste, und der Vorderfuss
fur sich, bereits geheilt, geborcn wurde."

t American Journal of the Medical Sciences,
No. xxxv. for May 1836, p. 90.

depression in its centre; the child was other-
wise quite perfect and healthy. Unfortunately
I could not obtain any information as to whe-
ther the hand had been found at the time of
delivery or not, the poor woman having been
attended only by an ignorant country midwife.
Three cases, very similar to the above, are de-
scribed by Dr. Simpson.*

I feel almost convinced that the removal of
limbs in this way is by no means so uncommon
an occurrence as the paucity of cases hitherto
recorded would, at first sight, lead us to con-
clude ; but the reason appears to me to be this,
when the separated portion of limb was not
accidentally discovered, the imperfection seems
to have been considered quite as a matter of
course, and without further examination, as
arising from imperfect development or monstro-
sity, and, consequently, no search was made
for the deficient part ; and, even if search was
made, the amputated member might have been
so small as to escape undiscovered, involved in
the membranes, or buried in coagula ; even
though the child to which it belonged had at-
tained considerable size, because its separation
may, as we have seen, take place a consider-
able time previous to birth ; this is noticed in
Mr. Watkinson's case, and is still more stri-
kingly exemplified in that described by Zagors-
ky, see Jig. 159.

With regard to the theories which have been
advanced to account for such accidents as that
which we have been considering, some, regard-
ing them as the effects of mental emotions in
the mother, or of accidents encountered by
her, have attempted to support their views by
details which Haller truly designates as " adeo
fabulosa ut fi dem auferant ; " those who attri-
buted this phenomenon to gangrene did so
from theory, and have received no support for
their opinions even from the facts which they
have themselves recorded; for it is expressly
mentioned that the parts which were the seat
of the injury seemed otherwise healthy, were
not discoloured, and at the point of division
were either partially or entirely healed over.
The explanation which facts fortunately enabled
me to offer does not depend on conjectural
reasoning or theoretical speculation for its
support, but its proof may be " oculis subjects
fidelibus" by the mere inspection of the parts>
which are preserved in my museum ; and with
regard to the nature of the process by which
the solution of continuity is effected, and the
foot, or other part amputated, it appears to be
strictly that of disjunctive atrophy, and in a
great degree similar to that by which the sepa-
ration of the funis from the umbilicus is accom-
plished.

Convulsive affections. — Having alluded to
convulsive movements of the child in another
place as the occasional cause of certain phy-
sical injuries to it, such as fractures and dislo-
cations, a few words on the subject will hardly
be misplaced here, although the affection itself
may perhaps not come exactly within the scope
of this article. The variety in the activity of

* Dublin Medical Journal, vol. x. p. 226.

330

FCETUS.

foetal motion is a matter of common observa-
tion, for, while some women suffer much and
almost constant annoyance from the excessive
restlessness of the child, others are hardly con-
scious of its movements.* That this is not
altogether dependent on a real difference in the
quality of the foetal motions, but in a great
degree the result of the greater or less nervous
irritability of the mother's system, must be ac-
knowledged; but, on the other hand, I think
we can hardly doubt that some of those pa-
roxysms of excessive turbulence are true con-
vulsions, and that the child sometimes thus
dies before birth, either under their influence
or by so entangling the cord as to compress
it, and put an end to the circulation through
it. The writer feels persuaded that he has met
with such cases, and he has read of others in
which, after a violent convulsive motion of this
kind, which had nearly caused the mother to
faint, all motion of the child has ceased to be
felt, and, after the lapse of a few days, delivery
has taken place, and the dead-born child has
exhibited appearances perfectly corresponding
with the belief of its having died at the time of
the convulsive struggle. In October 1834 the
writer attended a very nervous lady with her
second child, which, after about two hours of
easy labour, was born completely dead, al-
though full-sized and well thriven ; the cord
was twisted round the neck and also round one
of the arms. She told me that three days
before she was suddenly startled by the exces-
sive motion of the child "as if it was struggling
in convulsions;" this continued for a minute
or two, and was so violent and distressing as
to force her to exclaim, and nearly to produce
fainting ; from that moment she never felt the
child move.f

Effects of mental impressions on the mother.
— In the enumeration of the different causes
or sources of abnormal alterations in the foetus
we should not omit to include powerful im-
pressions made on the mind or nervous system
of the mother ; for although the writer would
be very far from wishing to advocate or coun-
tenance either the indiscriminate doctrine of
effects produced by the mother's imagination,
or the ridiculously absurd fabrications by which
it has been attempted to maintain it, he cannot
help thinking it quite consistent with reason
and the present state of our knowledge, to be-
lieve that such impressions may injuriously
affect the foetus, and it will at least be always
safe and prudent to act on such a presump-
tion; for " although," to use the words of
Morgagni,f " I do not approve these things,

* See some observations on this subject in the
writer's Exposition of the Signs of Pregnancy,
chapter v. p. 87.

t See Desormeaux, Diet, de Med. torn. xv.
p. 398. Duges, Diet, de Med. et de Chir. Pra-
tique, torn. viii. p. 295. A slight spasmodic sen-
sation communicated from the child to the mo-
ther, and sometimes repeated several times at
pretty regular intervals, like the efforts of hiccup,
has been by some attributed to the existence of
that affection in the child ; but with what degree
of reason the writer is not prepared to venture an
opinion.

| Epist. xlviii. art. 54.

(that is, the absurd stories,) there are cases
wherein it seems to me to be very hard to
depart totally and altogether from that opinion
which is common to the greatest men."* In a
case related by this celebrated writer, a mental
impression was quickly followed by the death of
the child ;f and if such an influence can thus
destroy its life, it is surely not unreasonable to
admit that it may have the power of modifying
organization.} An instance of this kind oc-
curred under my own observation about three
years ago, so remarkable that I trust I shall be
excused if I think it presents something more
than a mere though striking coincidence.

A lady, pregnant for the first time, to whom
I recommended frequent exercise in the open
air, declined going out as often as was thought
necessary, assigning as her reason, that she was
afraid of seeing a man whose appearance had
greatly shocked and disgusted her ; he used to
crawl along the flag-way on his hands and
knees, with his feet turned up behind him,
which latter were malformed and imperfect,
appearing as if they had been cut off at the
instep, and he exhibited them thus and unco-
vered in order to excite commiseration. I af-
terwards attended this lady in her lying-in, and
her child, which was born a month before its
time, and lived but a few minutes, although in
every other respect perfect, had the feet mal-
formed and defective precisely in the same way
as those of the cripple who had alarmed her,
and whom I had often seen. Now here was an
obvious and recognized object making a pow-
erful impression of a disagreeable kind, com-
plained of at the time, and followed by an
effect in perfect correspondence with the pre-
vious cause, there being between the two a
similarity so perfect that, with the distinguished
author above referred to, I " will not easily
suppose that chance could have been so inge-
nious, if I may be allowed to speak thus, and
so exact an imitator ;"§ and though I must ac-
knowledge in the words of Van Swieten " that
I do not understand the connexion of the cause
acting upon the mother with the effect observed
in the foetus," || I also agree with him, that it
must not therefore be denied that such a thing
has really happened. For some other observa-
tions on this subject the writer begs to refer to
a workf of his recently published.

Effects of inflammation, SfC. — The foetus in
utero, even at early periods of its developement,
is liable to a large number of organic altera-
tions, and even to lose its life, in consequence
of inflammation attacking the uterus of the
mother, the foetal appendages, or its own sys-
tem. From such causes arise a variety of pa-

* He refers to Boerhaave, Praelect. ad Instit.
§ 694, and to Van Swieten.

t Epist. xlviii. art. 18.

t A celebrated writer of the present day, Es-
quirol, is led from observation and experience to
refer one of the species of congenital predisposi-
tion to insanity, to the impression of terror on the
mind of the mother while pregnant.

§ Epist. xlviii. art. 54. Vide epist. Ixvii. art. 16.

|| Commentaries, sect. 1075.

^[ An Exposition of the Signs and Symptoms of
Pregnancy, chap. i. pp. 14 et seq.

FCETUS.

331

thological changes in the foetus, as atrophy,
arrest of developement, amputation of limbs,
and many other affections, as detailed in the
different sections of the present article.

With respect to those which seem distinctly
referrible to inflammation arising in the foetal
system and invading particular organs, the in-
stances are very numerous indeed; especially
in the thoracic and abdominal cavities, in which
striking indications of violent inflammatory ac-
tion have been frequently observed, both by
the writer and by others.

During the investigations made conjointly
by Madame Boivin and M. Chaussier, they
met with several cases of well-marked perito-
nitis, some of which were accompanied by con-
siderable effusion, which, however, did not exist
in others ; but in all there were found nume-
rous adhesions between the intestines.* Desor-
meaux records a case in which a child at birth
displayed all the evidences of violent enteritis,f
but afterwards recovered. In a case related by
Duges, all the abdominal viscera were found
agglutinated by a yellow coloured and firm
lymph ; there were false membranes on the
liver, the spleen, the bladder, &c.; the epiploon
was adherent to the intestines, which were ag-
glutinated into a lump, and were yellow, hard,
and thick. J Other instances of this form of in-
flammation are detailed by Billard,§ Carus,||
Cruveilhier,ir and others.

The stomach and intestinal canal have fre-
quently been found much diseased at birth.
In one instance of a still-bom child I found
the stomach in a state of intense inflammation,
and on its internal surface there were no less
than twenty-five patches of ulceration. Dr. C.
Johnson of this city found a similar condition
existing in the colon : the specimen is depo-
sited in the Museum of the College of Sur-
geons, Dublin. Cases of this kind are also de-
scribed by Billard,** who mentions an instance
in which he found in the duodenum a pedicu-
lated excrescence of a red colour and uneven
like a strawberry ; it was as large as a bean,
and in its structure, &c. resembled the vascular
tumours found in the intestines of adults. In
the same child there was also evidence of
chronic inflammation of the lower portion of
the ilium, with thickening of the mucous mem-
brane, which was of a slate colour .ff In ano-
ther case examined by the same writer, the
ilium and all the colon were found presenting
the characters of the disease named by Laennec
sclerosis, and consisting in a scirrhous indura-
tion of the submucous cellular tissue of the in-
testine. In a case observed by Cruveilhier the

* Recherchcs sur 1'Avortement, &c. p. 56, note ;
sec also Bulletin de la Fac. de Med. 1821, and
Proces verbal de la Maternite, Jan. 1812.

t Diet, de Med. art. (Euf, torn. xv. p. 403.

+ Recherches sur les Maladies les plus impor-
tantes et les moins connues des enfans nouveaux-
nes, par Ant. Duges, D.M. Paris, 1821.

S Maladies des Enfans, p. 444.

jl Gynskologia, ii. p. 251.

11 Livraison xv. pi. xi. p. 2, ob. 2.

'* Op. jam cit. p. 296 et seq. Atlas, pi. v. and
also p. 372.

tt Ibid. p. 373, 4.

small intestines presented several patches of
ulceration, and the coats so thickened that their
calibre was quite effaced.* Desormeaux thinks,
and apparently with good reason, that several
of the strictures and obliterations of hollow
canals, such as closing of the oesophagus, intes-
tinal canal, anus, urethra, &c. ought to be re-
ferred to the influence of former inflammation,
to which cause also there is great reason to
ascribe many instances of congenital blindness,
and especially those in which there is opacity
of the cornea.

The liver is not unfrequently the seat of in-
flammatory and other lesions before birth, a
variety of which have been noticed by different
writers; intense sanguineous congestion has
been often met with. Billard mentions two
instances in which the organ was found soft-
ened and giving out an odour of sulphuretted
hydrogen. It has also been found with tuber-
cles scattered through its substance at birth.f
Hoogeveen describes a tumour which was found
attached to the liver of a foetus of six and a
half months : it was hard and unequal, and as
if composed of particles of soft stone or cherry
kernels.^ Considerable serous effusion in the
abdominal cavity has been often observed.

The organs contained in the thoracic cavity
appear to be peculiarly liable to the invasion
of inflammatory action, and frequently exhi-
bit other abnormal conditions also. Cruveil-
hier goes so far as to say, that lesions of the
lungs are so frequent in the foetus, that in his
opinion disease of the lungs carries off as many
new-born children as adults.§

The lungs have been found hepatized in
still-born children, two instances of which oc-
curred to Andral,|| who says he found in ano-
ther case numerous abscesses in one lung.

M. Husson examined two children, one of
which was dead-born in the seventh month,
and had tubercles softened and in a state of
suppuration in the lungs, the mother being
healthy. I have met with instances of tuber-
cles in the lungs at birth, but in the cases
which came under my observation, the mothers
were affected with consumption ; under which
circumstances I have, in several instances,
found in the placenta a deposit of what appeared
to be perfect tubercular matter.

CruveilhierU has noticed instances of tuber-
cular induration, grey consolidation, scattered
masses of tubercular character containing pus,
and, in one case, there was serous infiltration
of the pulmonary tissue, which was of an olive
green colour. Billard ** relates similar cases of
pulmonary lesion, as does also Lobsteiu,t|- who

* Anat. Pathol. liv. xv. pi. ii. p. 4, ob. 7.
t See Billard ut supra, p. 421, and Meissner,
Kiiiderkrankhc'iten, i. s. p. 92.

| Tract de Morb. fretus humani, p. 63; see also
Bonetus, Sepulch. Anat. torn. iii. p. 104, Orfila,
Lemons de Med. Leg. Paris, 1828, i. p. 292, and
Andral's Pathol. Anat. translated by Townsend
and West, vol. ii. p. 704.
Liv. xv. pi. xi. p. 5.
Op. jam cit. p. 703.
Op. jam cit. liv. xv. pi. xi. pp.4, 6.
** Malad. des Enfans, pp. 499, 648.
tt Pathologischcn Anatomic, i. p. 321.

332

FOETUS.

found in the foetal lungs a calcareous concre-
tion.

Pleuritis. — The effects of inflammation at-
tacking the pleura before birth are not unfre-
quently seen. Billard relates the case of a
child which died on the fourth day after birth,
in whom the pleura was found greatly thick-
ened, and there were existing between its oppo-
site surfaces bands of adhesion as firmly orga-
nized as those found in an adult, eight or ten
years after a pleurisy.*

In a case described by Cruveilhier, the child
died thirty-six hours after birth, and there was
found double pleurisy with effusion of a sero-
lactescent pseudo-membranous fluid; and in
another instance described by the same writer,
in addition to anasarca, ascites, and purpura,
there existed hydrothorax, in a seven months'
child, which had lived only twelve hours :f
other instances are related by Veron, Orfila,
and others.

Purulent effusion. — The formation of pus
has been frequently observed in the foetus, both
in the form of secretion from the lining mem-
branes of cavities, and in distinct circumscribed
abscesses.

In cases of pleuritis and peritonitis, as alrea-
dy noticed,}; the abdominal and thoracic cavi-
ties have contained sero-purulent fluid. Cru-
veilhier found pus between the dura mater and
skull in a still-born child.§

Abscesses have been found in the thymus
and thyroid glands and in the supra-renal cap-
sules, see p. 334 ; and Andral found several in
one lung.||

Ollivier (d'Angers) has given an account of
the examination of a foetus of three months and
a half, under the skin of whose neck an abscess
was found .1[

I have very often seen small superficial ab-
scesses or pustules existing at birth, especially
about the neck, face, and head.

Dropsical effusions. — Several forms of serous
effusion have been already mentioned as taking
place during foetal life, and affecting either the
cellular tissue, the great cavities of the abdo-
men and thorax, those of the brain, or confined
to particular organs and their appendages.

Thus notice has been taken of the occurrence
of general anasarca, ascites, hydrothorax, hydrops
pericardii, serous infiltration of the lung, hydro-
cephalus, and hydro-rachitis or spina bifida.
In one instance which I examined some years
since there was general anasarca and serous
effusion into every one of the cavities ; the mo-
ther was healthy, but was in the habit of drink-
ing enormous quantities of ardent spirits.

The degree to which the head sometimes be-
comes enlarged in utero by dropsy is as extraor-
dinary as it is well known, and the difficulty of
delivery thus produced is equally a matter of
frequent observation with practitioners in mid-

* Op. jam cit. p. 501.

t Anat. Pathol. )iv. xv. pi. xi. p. 2, obs. 4.
j See Billard, Malad. des Enfans, p. 445.
$ Liv. xv. pi. xi. p. 6, obs. 10.
II Anat. Pathol. by Townsend and West, vol. ii.
p. 703.
f Arch. Gen. de Med. Mai 1834.

wifery. In one specimen in my possession, the
long diameter of the head is six inches, the trans-
verse five and five-eighths, and the circumference
nineteen inches : this case gave rise to the ne-
cessity of performing cephalotomy. In another
instance of twins I was called in, in conse-
quence of delivery of the first child being found
impracticable, the head being firmly retained
after the expulsion of the rest of the body. I
succeeded in extricating it, without perforation
or instruments of any kind ; it measured eight-
een inches and a half in circumference.* In a
case related by Perfect, f the head, when extri-
cated from the pelvis, measured more than
twenty-four inches in circumference. In an
instance of an hydrocephalic twin, described by
Dr. Patterson,^ the circumference of the head
was nearly twenty-one inches.

Cases have also occurred in which enlarge-
ment of the foetal belly from ascites has been
sufficient to impede delivery ; no such case has
come under the writer's observation, but others
have met with them.§ In another section of
this article a case is noticed, in which immense
distension of the foetal bladder produced great
difficulty in effecting the delivery. See p. 335.
In such cases hydrocele has been sometimes
observed at birth, and in other instances also.||

Ollivier (d'Angers) has described a case of
dropsy confined to the cavity of the great epi-
ploon in a well-formed child dead-born at the
eighth month : the laminae of the peritoneum
were separated by a serous fluid of a yellow
colour, and perfectly limpid, in which were
floating flakes of albumen : the posterior layer
of the epiploon was slightly opaque. The
tumour distended the abdomen enormously,
and there was fluctuation as in ascites : there
were present all the characters of circumscribed
inflammation of the epiploon. U"

Induration of the cellular tissue. — This pe-
culiar affection, in the great majority of
instances, does not invade the system for some
days after birth, and even then it is of rare
occurrence. My experience has not afforded
me an opportunity of examining more than
two cases, which were not congenital.

It has been already described in this work
(see CELLULAR TISSUE, p. 516), and it ap-
pears only necessary to add here that the
affection is sometimes found fully established
at birth. " Many children," says Andral,**
" come into the world with this affection," and
we have the testimony of Billardff and others
to the same effect. Jaundice has been more
frequently found than any other affection in

* An accurate cast of it is preserved in the wri-
ter's museum.

t Cases in Midwifery, vol. ii. p. 525.

j Lond. Med. and Surg. Journ. Sept. 17, 1836,
p. 86.

§ See Gardien, Traite complet d'Accouchemens,
torn. iii. p. 106 ; Duges, Diet, de Med. et de Chir,
Pratique, torn. viii. p. 303.

|| Graetzer, Die Krankheiten des Foetus, p. 159 ;
Billard, Malad. des Enfans, p. 630.

1[ Archives Generates de Med. Mai 1834.

** Anat. Pathol. by Townsend and West, vol. ii.
p. 580.

ft Malad. des Enfans, p. 178.

FCETUS.

333

conjunction with this oedema of the cellular
tissue. Of seventy-seven cases examined by
Billard, thirty were affected with jaundice.*

For a very full account of this subject see
Graetzer, die Krankheiten des Foetus : section
tderoderma.

Cutaneous affections. — Lesions of the skin
are probably the most numerous class of affec-
tions to which the foetus in utero is liable.

Some of these appear to be in a great mea-
sure mechanically produced in consequence
of the occurrence of other diseases, as in cases
of spina bifida, encephalocele, and other tu-
mours of the head. In these instances the
skin covering the tumour is first attenuated
as it is distended, and subsequently it disap-
pears altogether, and not unfrequently becomes
ulcerated. In some instances the injury
observed on the skin is the result of inflamma-
tion either attacking the skin itself or the mem-
branes of the ovum; in the former case abscesses
may form and ulceration be produced. I have
frequently seen instances of both, and also
very distinct cicatrices, which must have been
a considerable time in existence. Ollivier
(d'Angers) describes a remarkable case of ulce-
ration on the legs of a child bora with clubbed
feet.f I have more than one instance in my
museum of destruction of the skin from adhe-
sion having taken place between the foetus and
the membranes. Excrescences from the skin
have been observed by the last-named author,
Billard,| and others. The writer once attended
a lady who gave birth to a very fine healthy
child with two excrescences attached by pe-
dicles over the third phalanx of each little
finger. Naevi of different kinds existing at
birth are matters of common observation, and
in not a few instances petechiac have been
observed in the form usually denominated pur-
pura haemorrhagica.§

Very many instances of the eruptive diseases
have been noticed in the immature foetus and
child at birth. Vogel and Rosen mention in-
stances of chilbren born with the traces of
measles, and Guersent says|| he saw an infant
born with the eruption on it, having taken the
disease from the mother.

In the course of the last year I attended a
patient who was delivered a month before her
time, when just recovering from an attack of
scarlatina ; the child's skin exhibited the erup-
tion in several places : it recovered.

* Ibid, p. 179. See also Deutschberg, Dissert,
de tumor, nonnul. congenitis,Vratislav, 1822, p. 21 j
and Abbild. t. ii. Leger, Considerations sur Tin-
durcissement du tissu cellulaire chez les nouveaux-
nes. Denis, Theses de Paris, n. 159, annee 1824,
de Tindurcissement du tissu cellulaire, &c. and
Recherches d'Anat. et de Physiol. Pathol. sur plu-
sieurs Maladies des Enfans nouveaux-nes, Paris,
1826, p. 145. Orfila, Le5ons de Med. Leg. p. 375.
Alibert, Nosol. Naturelle, p. 495-499.

t Arch. Gen. de Med. Mai 1834.

; Maladies des Enfans, p. 79.

§ See Billard, op. jam cit. p. 92, 3. Graetzer,
p. 60. Cruveilhier, liv. xv. pi. ii. p. 2, 3, obs.
4 and 5.

|| Diet, de Med. t. xviii. p. 513. For several
other references see Graetzer, die Krankheiten
des Foetus, p. 49.

Small-pox has been observed on the child at
birth and under remarkable circumstances, as
in cases where the mother had not been affected
with the disease during gestation. See cases
by Jenner, Med. Chir. Trans, vol. i. p. 269 ;
and a very remarkable one by Mead, in which
" a certain woman who had formerly had the
small-pox, and was now near her reckoning,
attended her husband in the distemper. She
went her full time and was delivered of a dead
child. It may be needless to observe that she
did not catch it on this occasion, but the dead
body of the infant was a horrid sight, being
all over covered with the pustules ; a manifest
sign that it died of the disease before it was
brought into the world." Works, edit. 1767,
p. 253.

Billard* mentions having seen in theMuseum
of Guy's Hospital a foetus of six months covered
with pustules of small-pox, which was born
when the mother was just recovering from the
disease.

" Mary Gatton had confluent small-pox in
the seventh month of her pregnancy ; eighteen
days from the first attack of the eruptive fever
she was taken in labour and delivered of a
child, which seemed to have been dead five or
six days. Its body was covered with confluent
small-pox. The pustules were white and full
of matter, and from their size seemed to have
nearly attained their maturity /'f

" A lady was inoculated in the seventh
month of her pregnancy, and on the ninth day
from the accession of the eruption, which was
moderate, she received a fall ; from that period
the motions of the child were no longer per-
ceptible : in eight days after she was taken in
labour, and delivered of a dead child covered
with a great quantity of variolous pustules,
which were prominent and in a state of suppu-
ration."];

Pemphigus has been observed on the child
at birth by Lobstein,§ Joerg,|| and others.

When the system of either parent retains a
taint of syphilis, the child very frequently exhi-
bits at the time of birth unequivocal evidence
of being contaminated by the disease, and
sometimes of having already fallen a victim to
its ravages; though in the majority of such
cases the children are born alive, often appa-
rently healthy, and do not exhibit any appear-
ance of disease for a few weeks.

In many instances children so tainted are
born in a state of complete putridity, and with
the skin either already stripped off or quite
loose and detached ; in other instances, which
are much more rare, the children have been
born alive, with a well-marked syphilitic erup-

* Op. jam cit. p. 97. See also Graetzer, op.
cit p. 27.

t Paper by Dr. Bland in Simmons' Lond. Med.
Journ. vol. ii. p. 204.

$ Mem. Lond. Med. Soc. vol. iv. p. 364.

$ Journ Complem. du Diet, des Sci. Med. t. vi.
p. 1.

|| Handbuch der Kinderkrank. 1826, p. 310.
See also Siebold, Journal fur Geburtshiilte, &c. iv.
Bd. 1, St. 1823, s. 17. Meissner, Kinderkrank-
heiten 1. p. 406, 410. Wichmann, Beitrag zur
Kenntniss von Pemphigus, p. 15.

334

FOETUS.

tion on the skin, as in the cases recorded by
Cruveilhier,* Dr. Collins,f and others. I
am indebted to Dr. Collins for a very accurate
drawing of one of his cases; the skin of the
child generally was of a very dark hue ; scat-
tered over different parts of the body were
brownish or copper-coloured blotches, inter-
mingled with pustules and with large vesicular
patches containing a straw-coloured purulent
fluid, along with which there were also nume-
rous superficial ulcerations of a bright red
colour.

Affections of the heart and pericardium. —
Independently of the innumerable irregularities
of structure and malformation to which the
heart is liable, experience has shewn that both
it and its pericardium are sometimes attacked
by disease in utero.

Denis gives an account of a case of hyper-
trophy of the heart at birth.]: The following
case of scirrhous tumours in the heart is
described by Billard.§ On opening the body
of a child of three days old he found on the
anterior surface of the heart along the inter-
ventricular line three projections of a whitish
colour ; they were buried in the substance of
the wall of the left ventricle and the inter-
veritricular septum, projecting a little into the
cavity of the organ. When cut into, they
creaked under the scalpel, and the cut surface
exhibited closely interlaced fibres, perfectly
resembling, both in appearance and form, those
of scirrhus. Cruveilhier details a highly
interesting case of aneurism of the right auricle
and ventricle in consequence of the obliteration
of the orifice of the pulmonary artery. The
child was born at eight months and a half in a
state of extreme debility, and lived only five
days, all which time the respiration was im-
perfect, embarrassed, and almost convulsive.
On examination the heart was found enor-
mously enlarged, filling more than half the
thorax, and pushing back the lungs, which were
of small size. The right cavities were so en-
larged as to constitute seven-eighths of the
whole organ ; the valve of the right auriculo-
ventricular opening was attached and fixed in
such a way that the blood passed as freely
from the ventricle into the auricle as in the
opposite direction, and there were floating
granulations on the free edge of the valve.
The orifice of the pulmonary artery was com-
pletely obliterated, but otherwise the artery
and its divisions were healthy .|| " How could
life," asks Cruveilhier, " be maintained for five

* Anatomie Pathol. liv. xv. pi. 11, p. 6, obs.

t Practical Treatise on Midwifery, &c. p. 608, 11.
On this subject see Doublet, Memoire sur la Verole
des Enfans nouveaux-nes, Paris, 1781. Dr. Beatty,
Trans. Assoc. Coll. Phys. in Ireland, vol. iv. p. 31.
Haase, de Syphilidis recens natorum pathogenia,
Lipsi*, 1828. J. F. H. Albers, Ueber die Er-
kenntniss und fiir der Syphilischen Hautkrank-
heiten, 1832. Wendt, Kinderkrankheiten iii. Aufl.
p. 109. Duges, Diet, de Med. et de Chir. Pra-
tique, vol. viii. p. 298. Colles, Practical Obser-
vations on the Venereal Disease, 1837, p. 262.

\ Recherches d'Anat. et de Phys. Pathol. &c.
des Enfans, p. 353, Paris, 1826.

$ Maladies des Enfans, p. 647.

\\ Anat. Pathol. liv. xv. pi. ii. p. 4, obs. 8.

days ? there did not pass a drop of blood into
the lungs from the right ventricle. I think
that the entrance of the blood into the lungs
was partially accomplished through the ductus
arteriosus ; it is probable that life would have
been maintained if the foramen ovale had
remained free and open." It appears to me
that the explanation here offered by the author
is probably correct, as I once saw an instance
in which a child affected with the morbus
cceruleus lived a year and a half, and on exa-
mination we found that the aperture of the
pulmonary artery was completely obliterated
where it should have joined the right ventricle,
but the aorta had an opening into it from both
ventricles, and the ductus arteriosus was quite
open and free ; and my opinion then was that in
this way sufficient blood was transmitted to the
lungs and revivified for the imperfect support of
life ; the foramen ovale was open. Billard also
met with an instance of aneurism of the ductus
arteriosus in a new-born child : the heart was
larger than usual, the duct was of the form of a
large cherry-kernel and filled with fibrinous co-
agula disposed in layers, as they are found in
the aneurisms of adults.* How far this affection
truly deserves the name of aneurism seems
somewhat doubtful; but the writer, not long
since, met with a similar condition of the
ductus arteriosus when examining the body of
an infant which died suddenly.

Pericarditis. — Evidences of the existence of
this disease have also been frequently met with.
In a child only two days old Billard found
between the opposite surfaces of the pericar-
dium adhesions so firm as to lead to the con-
clusion that they must have been formed during
foetal life ;f and in the case of a child which
lived only an hour Cruveilhier found, in addi-
tion to anasarca, ascites, and purpura, effusion
in the sac of the pleura and a great quantity of
fluid in the pericardium.]: Speaking of this
affection, Andral says, " It is a fact which one
would never imagine, a priori, that irritation
of the pericardium terminating in the formation
of false membranes or purulent effusion into
its cavity is a common enough disease in the
foetus, even more so, perhaps, than in the
adult."§

The thy mm gland. — Considering the num-
ber of pathological lesions to which we have
just seen that the lungs are liable, although
being organs in a state of complete quiescence
during foetal life, we cannot be surprised that
the thymus, which attains so great a degree of
development (if not its greatest) before birth,
should frequently exhibit evidences of morbid
over-action, and accordingly several instances
of the kind have been recorded.

Cruveilhier relates a case of a child which
lived only a few minutes, and under whose
sternum there was a large collection of pus
which was lodged partly in the thymus and
partly in the anterior mediastinum; the thymus

* Op. jam cit. p. 567, and atlas pi. 8.
t Ibid, p. 571.

j Anat. Pathol. liv. xv. pi. ii. p. 3, obs. 5.
§ Pathol. Anat. by Townsend and West, vol. ii.
p. 702, 3.

FCETUS.

335

was much enlarged, contained several tuber-
culated cells rilled with pus. He considers it
a tubercular affection of the thymus, or in
other words, a chronic inflammation of that
organ.*

Veronf found the thymus at birth very volu-
minous, much inflamed, and containing a
quantity of pus.

The thyroid gland. — This organ has been
found exhibiting similar lesions to those just
described, instances of which are recorded by
Francus,! Carus,§ Hufeland,|| and others.

Abnormal conditions of the fatal bladder.—'
The consideration of this subject necessarily in-
volves the disputed question, whether urine
be secreted by the child before birth, of which,
however, the writer feels fully convinced by
facts within his own observation.

In the year 1824 I attended a patient who
was delivered of a still-born child, which had
an unusual prominence of the lower part of the
abdomen ; on laying my hand over the part, I
ascertained the existence of a tumour of extra-
ordinary firmness, which, on opening, I found
to be the bladder, distended to the size of a
large orange, remarkably tense, and containing
a fluid having the appearance of urine : it was
not, however, chemically examined ; the ure-
ters were so distended that their coats were
diaphanous, the diameter of those canals being
nearly an inch, and they were very much con-
voluted in their length, which greatly exceeded
what is usual : the pelves of the kidneys were
in a similar state of distension ; the urethra,
where it joined the bladder, was completely
impervious.

In the course of the last year I was in
attendance on a lady who had in her former
labours suffered frightfully from haemorrhage
coming on after the birth of the child; as a means
of preventing the recurrence of so dangerous
an accident, I conducted the delivery with the
greatest caution, and allowed the uterine con-
traction to effect the expulsion of the child,
even to the feet : but while it was lying with
the legs and thighs still within the vagina, the
penis became partially erected, and a stream
of urine was expelled in an arch, to the amount
of at least six or seven ounces.

The following case, related by Mr. Fearn,1[
is a striking example of the degree to which
the bladder may be affected before birth. After
the expulsion of the child's head, the extrac-
tion of the body was found impracticable, even
after mutilation of the upper extremities, and
evisceration of the thorax. An elastic tumour
was now felt in the situation of the diaphragm ;
this was punctured, and immediately an im-
mense quantity of reddish watery fluid escaped,
and the delivery was easily completed. On

* Anat. Pathol. liv. xv. pi. ii. fig. 2.

f Mem. dans la seance de 1'Acad. Royale de
Med. 26 Aout, 1825.

$ Eph. N. C. Dec. 11, an. v. obs. 223.

$ Leipz. Lit. Zeit. 1816, p. 238 ; 1817, p. 301 ;
1819, p. 452 : 1820, p. 241, and Gynskologia ii.
p. 253.

|| Journal, 1827, Bd. 64, p. 26.

^ See Lancet, vol. ii. for 1834-35, p. 178.

examination, the child appeared to have arrived
at the seventh or eighth month ; the parietes of
the abdomen were large and flaccid, and in its
cavity was an immense sac, the coats of which
were three or four lines in thickness, and tra-
versed in every direction by numerous large
vessels gorged with blood. This sac was, after
careful dissection, distinctly made out to be
the urinary bladder which had been enormously
distended by the secretion from the kidneys ; its
muscular fibres were much hypertrophied ; it
had no communication with the urethra; the
penis was well developed, but the urethra passed
down along it only as far as its membranous
portion. The kidneys were flabby, and their
secreting and tubular portions much attenuated,
owing to the distension the pelvis of each had
undergone; the ureter on each side, when
inflated, was nearly an inch in diameter, and at
one side the valvular opening into the bladder
was large enough to admit readily the point of
the little finger. The bladder when filled with
water contained upwards of two quarts. The
rectum terminated in a blind pouch in the pelvic
cavity, and there was, consequently, no anal
opening.* There was besides an arrest of de-
velopment of the right lower extremity, the
limb becoming suddenly wasted immediately
below the knee, and having attached to it a
foot no larger than, and in every way resem-
bling that of an embryo of the tenth or twelfth
week. The body appeared in other respects to
have been tolerably well nourished.

In a case mentioned by Dr. Lee,-f- which
occurred to Mr. Hay of Osnaburg-street, the
child's abdomen was so large at birth in the
eighth month that it passed with difficulty
through the pelvis, and the enlargement was
found to arise from an accumulation of fluid
within the kidneys, produced by an impervious
state of the ureters. The right kidney, which
resembled a thin cyst filled with a watery fluid,
was larger than the head of the child ; the left
did not exceed half this bulk ; it contained four
ounces, and the other nine, of a fluid resem-
bling urine, and which, when examined by Dr.
Prout, was found to contain the chemical con-
stituents of that fluid. The child had also a
double hare-lip and clubbed feet.

Mr. Howship examined the body of a child
which died a few hours after birth in the eighth
month ; it had distorted feet, imperforate anus,
and the lower part of the abdomen was occupied
by a large circumscribed tumour, which proved
to be the bladder, the coats of which had ac-
quired a very extraordinary degree of strength
and thickness ; the ureters were thin and mem-
branous from distension and curiously con-
torted, and terminated in what appeared like a
congeries of small hydatids no larger than garden
peas, loosely connected together by a cellular
texture ; these were the kidneys in a morbid state :
the urethra was impervious. Mr. Howship
alludes to two other nearly similar cases.J

* The writer had lately an opportunity of ex-
amining a specimen of this peculiarity in Dr. Mur-
phy's collection.

t Med. Chir. Trans, vol. xix. p. 238.

j Treatise on the Urine, &c. 1823, p. 374, 6.

336

FCETUS.

Other instances of this condition of the
urinary apparatus are recorded by other writers,*
and in particular Meckel has related a case in
which it was conjoined with several other very
remarkable deviations.f

Urinary deposits. — It is no slight confirma-
tory proof of the secretion of urine by the foetus,
that urinary deposits have been discovered in
the kidneys, ureters, and bladder. Brendelius
mentions two cases, in one of which a child
only two days old, and in the other one of
eight days old, passed calculi before^leath; and
calculi were also found in their bladders. J

Loeseke found a calculus in the kidney of a
new-born child.§ Hoffman relates the case
of a German princess who was afflicted with
renal calculus, and gave birth to a daughter,
who from the hour of birth suffered excru-
ciating pain when passing water; the child
died when three weeks old, and on examin-
ing the body a calculus as large as a peach
kernel was found in the bladder.j) Orfila
saw two cases in which there were calculi in
the bladder and in the kidneys at birth.^f

Premature developement of teeth. — It is
hardly necessary to remark that at an early
period of fatal existence the teeth begin to be
developed, and it is equally a matter of com-
mon observation that they do not in general
emerge from their alveoli and pass through the
gums until several months afterbirth. But many
instances have been observed in which some of
them have been found developed and projecting
above the gums at birth.

I have before me at this moment four teeth
of this kind taken from the gums of the only
two children of a patient of mine; in each
child the two middle incisors of the lower jaw
were found projecting at birth, and in each
instance it was found necessary to extract them
after a few days, in consequence of their cut-
ting the child's tongue and preventing it from
sucking.

Louis XIV. and Mirabeau are well-known
instances of this premature developement of
teeth, and many other cases are recorded by
different authors; for several references see
Graetzer.**

This abnormal condition of the teeth has
been frequently found accompanying certain
deformities of the face, especially hare-lip and
cleft palate.

Intestinal worms. — However repugnant to
our ideas of probability the existence of worms
in the intestines of the foetus in utero may at

* See Billard, Maladies des Enfans Nouveaux-
nes, &c. p. 431 et seq. ; Ollivier d' Angers. Archiv.
Gen. de Med. t. xv. p. 371 ; Mr. Wilson, Med.
Chir. Trans, vol. xix. p. 248. ; Ruysch, Sandifort,
Wrisberg, Chausster, and Vrolik have described
such cases.

t Joum. Complem. des Sciences Med. t. xiii.
p. 335.

t Program, de Calcul. Vesic. et ceteris Natal. :
also Obs. Anat. Dec. iii. ob. 1.

$ Obs. Anat. Chir. Med. p. 39.

|| Dissert, inaug. de morbis foetus in utero ma-
terno, Halae Magdeb. 1702.

U Lemons de Med. Leg. Paris, 1828, t. i. p. 297.
* Die Krankheiten des Foetus, p. 141.

first sight appear, too many instances of the
fact have been observed by authors of credit to
allow of any doubt remaining on the subject;
I must, however, add that no case of the kind
has come under my own observation. So far
back as the writings of Hippocrates, we have
an account of a tapeworm found in a fetus ;
and it seems very probable that in the instance
mentioned by Hufeland,* in which he found a
tapeworm thirty ells long in a child of six months
old, the animal must have existed in the child
before birth. Kerkringiusf found in a foetus of
six months and a half, whose abdomen was
much enlarged, worms of the kind usually met
with in children (ascaris lumbricoides or vermi-
cularis). DolaeusJ speaks of a dead-born
child in whose intestines he found a knot of
worms; and similar observations have been
made by Schroster and others. According to
Roederer and Wagner the whipworm (trichuris)
was found in a case in which the fetus partici-
pated in the disease (morbus mucosus), under
which the mother was labouring at the time.
Other instances are noticed by Brendel,§
Bloch,|| lludolphi,1T and Graetzer.**

ImpcrJ orate anus. — Cases of imperforate
anus, of the ordinary kind, are too numerous
and too well known to require any particular
observation ; but this imperfection has been
occasionally accompanied by other peculiarities
deserving to be noticed ; one or two are,
therefore, subjoined in addition to the full
account of congenital malformations of this
part given in the article ANUS.

Dr Steel has recently recorded the particu-
lars of a case of a new-born infant, who was
observed, one or two days after birth, to have
feculent matter, mingled with the urine, dis-
charged by the urethra. The parts behind the
scrotum were perfectly natural in every respect,
except the want of an anus, of which there
was not the slightest vestige ; the spot where it
should have been was smooth, and of a uni-
form colour with the adjacent parts; the
sphincter muscle was evidently wanting, and
there was nothing to indicate an accumulation
of faeces in the vicinity.

For the first three or four weeks the child
continued fretful, and was evidently declining
in vigour and growth ; but from that period to
a short time before its decease it apparently
suffered but little, nor did its growth or
strength seem to be at all impeded. It was
born on the 13th of April, and in the latter
part of the ensuing March its bowels became
obstinately obstructed, the scrotum enlarged,
and became extremely tender; and on the 30th
of the same month it died.

On dissection, two apple-seeds of a large

* Journal Bd. 18, st. i. p. 3, quoted by Brem-
ser; Traite des Vers intestinaux, p. 181.

t Specilegium Anatomicum, Amstel. 1670, obs.
79, p. 154.

Encyclop. Med. lib. vi. cap. 10, p. 1011.
Pallas, dissert, de inf. viv. p. 59.
Preisschrift liber die Erzeugung Eingeweide-
wurmer, Berlin, 1782, p. 38.

IT Entozoa i. p. 387 ; Pallas, p. 43.
** Die Krankheiten des foetus, Breslau, 1837,
p. 10V.

FCETUS.

337

size, together with a portion of the capsule or
hull which surrounds them, were found lodged
in the urethra, about three-fourths of an inch
from its termination ; they were so situated as
completely to obstruct the passage, and a
small opening had been formed immediately
behind them in the urethra, through which
some of the contents of the bladder had been
infused into the cellular tissue, and extended
to the scrotum, producing inflammation and
gangrene, and so causing the child's death.

The contents of the abdomen appeared
perfectly natural, except the colon sinistrum
or descending colon, which was found to be
entirely destitute of the sigmoid flexure ; the
gut passed along the left lumbar and through
the iliac regions in nearly a straight line to the
neck of the bladder, into which, after making
an abrupt but imperfect curve, and being sud-
denly contracted in its dimensions, it was in-
serted just behind the base of the prostate
gland. The aperture which united the gut and
bladder into one common receptacle for their
respective contents was of sufficient capacity
to admit a large-sized goose-quill ; through
this aperture the urine found a ready egress
into the intestine, where, becoming united with
the contents of that receptacle, it was forced
back into the bladder, and finally excluded
through the urethra. The space between the
perineum and the termination of the intestine
was occupied by a soft fatty substance, but there
was not the slightest vestige of a gut.*

The subjoined woodcut represents the parts
of one half the natural size when merely in-
flated.

Fig. 160.

a, the penis, b, the bladder, c, the colon.

We have given the above in detail, not
merely on account of the remarkable nature of
the anatomical deviation, but as connected
with the still more interesting fact, that life
was under such circumstances sustained, and
healthy defsecation accomplished for nearly a
year after birth.

M. Roux of Brignolles operated success-
fully in May, 1833, on a new-born child, in
whom the same malformation appears to have
existed ; no trace of anus could be discovered

* American Journal of the Medical Sciences,
No. xxx. p. 404.
VOL. II.

in the perineum, and the rectum terminated at
the urethra, through which some faecal matter
was discharged ; the infant lived, and enjoyed
good health.*

Rickets. — Deformities of the bones arising
from rickets have been occasionally observed
both in the child at birth and in the immature
foetus ; but the instances have been few in
number ; the writer has never had an opportu-
nity of examining a case of the kind, but they
have been described by authors of credit.
Pinel has given an account of a ricketty foetus
of eight months, in which the deformity was
chiefly confined to the lower extremities. f
ChaussierJ examined another at the Maternite
at Paris, in which there was distortion of the
back and thorax, with softness and flexibility
of the bones. Several other writers of respect-
ability have described this aflTection.§

Jaundice. — The foetus in utero, as well as
the child at birth, has been found exhibiting
all the characters of true jaundice. In the case
of a lady, related by Duges,|| who was herself
liable to frequent attacks of this disease, and
had biliary calculi, all her children were born
dead, and strongly coloured by jaundice. It
is not, however, always fatal to the child affected
with it before birth.

Cirronosis. — Under this namelf Professor
Lobstein of Strasburg has described** an affec-
tion of the foetus in which the serous or trans-
parent membranes, as the peritoneum, pleura,
pericardium, and arachnoid, were stained of a
strong yellow colour, which in some instances
was found to pervade also the brain, spinal
marrow, and the great sympathetic nerves.
The cause of this peculiar colour is altogether
a matter of doubt, but it differs from jaundice
in not affecting the parenchymatous cellular
tissue of internal organs, the subcutaneous
cellular tissue, nor the skin, and it is found so
early as the third and fourth months, a period
at which the bile is not as yet secreted. For a
more ample account of this affection see the
article CIRRONOSIS.

Accidental morbid tissues observed in the
foetus. — Some of these have been already inci-
dentally noticed under different heads in the
present article, but it appears desirable to

* See Medical Gazette for June 28th, 1834 ; or
the American Medical Journal, No. xxx. p. 531,
where there is an account of the mode in which the
operation was performed.

t La Medecine eclairee par les Sciences Phy-
siques, torn. i. p. 111.

$ Diet, des Sci. Med. torn. xvi. p. 67.

§ Loder, Index Preparator. &c. Mosquae, 1823,
sec. ii. D; Sartorius, Rachit. Congenit. Obs. 4to.
Lipsiae, 1826, cum tabulis ; Romberg, De Rachit.
Congenit. Berolinae, 1817, cum tabulis ; Otto,
Seltene Beobachtung, 1 Sam. tab. i. fig. 1. ; Seem-
mering, Abbildung. u. Beschreib. einiger Missge-
burten, p. 30. pi. xi ; Bordenave, Mem. de Mathem.
et Phys. torn. iv. p. 545 ; Lepelletier, Maladie
Scrofuleuse, Paris, 1830; flenckel, Abhandl. Chi-
rurg. Oper. Th. ii. p. 14 ; Glisson de Rachitide,
p. 178.

|| Diet, de Med. et de Chir. Prat. t. viii. p. 301.

^f From xjppof, yellow, and votroe, a disease.

** In the Repertoire Generale d'Anatomie, &c»
No. i. p. 141, and plate iv.

7.

338

BONES OF THE FOOT.

advert to them here as a group for the sake of
distinction.

Tubercles have been found by the writer and
others, as already referred to, in the lungs,
liver, brain, spleen, peritoneum, and mesen-
tery, the glands of which have been found by
(Ehler in a state of complete scrofulous dege-
neration, not only in children born of a scro-
fulous mother, but in others also : in some
instances the tubercular formations were found
in a state of suppuration.*

Scirrhous tumours have been already des-
cribed as found in the heart.

The only instance of fungus haematodes in
the fetus of which the writer is aware, is one
which he had, not long since, an opportunity
of observing f with Dr. Alcock and Dr. Evan-
son in a child which lived only nine weeks ; at
birth an unusual fulness was observed about
the perineum and anus, which increased ra-
pidly until these parts became greatly pro-
truded, and a tumour was formed of the size
of a very large orange ; convulsions came on,
and the child died after much suffering : on
examination, the tumour was found to be a
perfect specimen of fungus haematodes.

BIBLIOGRAPHY. — Licetus ( Fortun.) De perfecta
constitutione hominis in utero, &c. 4to. Patavii,
1616'. Alsaro delta Croce, (Vincent), Disquisitio
generalu ad historiam foetus emortui nonimestris,
&c. 4to. Romae, 1627. Riolanus ( Joan. ) Foetus histo-
ria, 8vo. Parisiis, 1628. Fridericus (Joan. Arnoud.)
Tvfj.va.o- pa. ia.Tp.xov foetum quoad principia, partes
communes et proprias, differentias, morbos et sym-
ptornata, eorumdemque curationem offerens atque
exponens, 4to. lenae, 1658. Frank de Frankenau,
(Gcorg.) De impuberibus generantibus et parien-
tibus, foetu in foetu, embryo in embryo, et foetu ex
mortua matre, &c. Duettel, (Phil. Jac.) De
morbis foetus in utero materno, 4to. Halae Magdeb.
1702. Valentini, De morbis embryonum, Giessse,
1704. Storch, Kinderkrankheiten, Eisenach, 1750.
Socin (Joan. Abel.) De foetu hydropico, 4to. Basils,
1751. Jaeger, Observationes de feetibus recens
natis jam in utero mortuis, &c. 4to. Tubings, 1767.
Raulin, Traite des Maladies des Enfans, Paris,
1768. Gruner, De Naevorum Originibus, Jenas,
1778. Zierhold, De notabilibus quibusdam quae
fcetui in utero contingere possunt, Halas, 1778.
Hooyeveen, Tractatus de foetus humani morbis, 8vo.
Lugduni Bat. 1784. Engelhart, Dissertatio inaug.
Med. sistens morhos hominum a prima conforrna-
tione usque ad partum, 4 to. Jenae, 1792. Chaus-
sier. Discours prononce a 1'hospice de la Maternite,
Juin 1810 et Juin 1812. Ej. Proces Verbal de la
distribution des prix, 1812. Ej. Bulletins de la
Faculte de Medecine. Paris, 1813 et 1821. Murat,
Diet, des Sciences Med. art. Foetus, Paris, 1812.
Feller, Padiatrik, Subzbach, 1814. Oehler, Pro-
legomena in embryonis humani pathologiam, Diss.
inaug. Lipsiae, 1815. Joerg, Zur Physiologic und
Patbologie des Embryo, Lipsiae, 1818. F. B.
Osiander, Handbuch der Entb'indungskunst, Tubin-
gae, 1819. Seeligmann, Dissertatio de morbis
foetus humani, Erlangae, 1820. Zuccarini, Zur
Beleuchung der Krankheiten der menschlichen
Frucht, Erlangen, 1824. Desormeaujc, Diet, de
Med. torn. xv. art. (Euf; Paris, 1826. Prosper, S.
Denis, Recherches d'Anat. et de Physiol. patholo-
gique sur plusieurs maladies des Enfans nouveaux
nes. Paris, 1826. Hufeland, Die Krankheiten der

* See section on the state of the Lungs, and
Billard, p. 648.

t See his Exposition of the Signs and Symptoms
of Pregnancy, &c. p. 152.

Ungebornen und die Vorsorge, &c. Journal der
praktischen Heilkunde, 1827. Meismer, Kinder-
krankheiten, Leipzig, 1828. Hardegg, De Morbis
foetus humani, Tubing*, 1828. Billard, Traite
des Maladies des Enfans nouveaux-nes et a la
mammelle, Paris, 1828. Bergk, De Morbis foetus
humani, Lipsiae, 1829. Cruveilhier, Anatomic
Pathologique du coi%ps humain, Paris, 1829.
Andry, Memoire sur les Maladies du foetus, &c.
Journal des Progres, 1830. Zairmeyer, De Mor-
bis foetus, Bonnae, 1832. Graetzer, Die Krankhei-
ten des foetus, Breslau, 1837.

( W. F. Montgomery.)

FOOT, BONES OF THE (in human ana-
tomy).— The foot (pes ; Gr. Trovq; Fr. le pied ;
Germ, der Fuss) forms the inferior segment of
the lower extremity, being united to the leg at
the ankle-joint nearly at a right angle, so that
in the erect position on a plane surface the foot
is horizontal. The outline of the foot circum-
scribes an ovoidal figure, the long axis of which
is directed from before backwards ; and in the
same direction the foot is divided into three
segments, the anterior one surpassing that
behind it in mobility, but falling short of it in
solidity. These divisions are the tarsus, meta-
tarsus, and the toes.

The size of the foot, taken as a whole, varies
in different individuals : it always exceeds that
of the hand, chiefly, however, in length and
thickness, its breadth being less than that of
the hand. In the hand we find divisions pre-
cisely analogous to those of the foot above
mentioned and similarly constructed, with this
difference, that the solid part of the foot is
more solid and more developed in every way
than the corresponding part of the hand, but
the moveable parts possess less mobility than
the analogous segments of the hand. The
parts of the foot and hand, as Mr. Lawrence
observes, are disposed inversely in respect to
their importance. The posterior portion of the
former and the anterior of the latter are of the
most consequence and possess the most remark-
able characters. In short, the foot is nothing
more than the hand so modified as to afford a
firm basis of support to the inferior extremity
in the erect posture. One of the most remark-
able of these modifications is that manifest in
the metatarsal bone of the great toe, which
corresponds to the metacarpal bone of the
thumb. The latter bone is connected with the
carpus so that it forms an acute angle with the
second metacarpal bone. It enjoys at its arti-
culation with the carpus a considerable degree
of mobility, in virtue of which exists the
opposable faculty of the thumb. On the other
hand, the metatarsal bone of the great toe
enjoys but a very limited degree of mobility at
its articulation with the tarsus : it lies parallel
to the adjacent bone and possesses considerable
strength. These remarkable differences, says
Mr. Lawrence, are easily understood when we
consider that the great toe, as one of the points
on which the body is supported, requires
solidity; while the thumb, being concerned in
all the numerous and varied motions of the
hand, must be organised for mobility. Those
animals in which the inferior segments of both
anterior and posterior extremities are eminently

BONES OF THE FOOT.

339

required for prehension have the inferior seg-
ments of all four extremities organised as hands,
and are thence denominated Quadrumanous.

The most elevated part of the foot is at its
posterior part, where it contributes to form the
ankle-joint; thence it inclines forwards, gra-
dually expanding transversely, and presenting
a more or less convex surface from behind
forwards. This is the dorsum pedis, the instep.
The inferior surface likewise expands as it
proceeds forwards. It is slightly concave in
the transverse direction, and more manifestly
so in the antero-posterior one ; this latter, how-
ever, varies in a degree proportionate to the
convexity of the dorsum. This is the plant a
pedis, the sole.

The internal edge of the foot corresponds to
the great toe, the external edge to the little toe,
the anterior to the ends of the toes, and the
posterior extremity of the foot is formed by the
os calcis.

I. Tarsus (Germ, die Fusswurzel). — Nearly
the posterior half of the foot is occupied by
the tarsus, which is arranged in the form of an
arch, convex superiorly, on the highest point
of which rests the weight of the leg. Seven
bones enter into the formation of the tarsus ;
they are arranged in two sets or rows. The
posterior row is formed by the astragalus and
os calcis, the anterior row by the os naviculare,
the os cuboidcutjii and the three cuneiform
bones. Through the medium of the first two
bones of the anterior row that row is articulated
with the posterior.

1 . Astragalus (ac-r^aya^o?, Ttrgugoq, os ba-
listfE, talus; Fr. Vastragale ; Germ, das Knoc/i-
elbe.in oder Sprungbein). — This bone is situated
between the tibia and the os calcis, and has
the navicular bone in front of it. In point of
size it ranks second among the tarsal bones,
the os calcis being first.

The astragalus is commonly divided into
three parts for the purposes of description, viz.
the head, neck, and body. The head is that
convex portion which forms the anterior part of
the bone, and which is entirely articular. This
smooth, oval, articular head is adapted to the
posterior concavity of the navicular bone. The
aspect of this surface is forwards, inwards, and
slightly downwards. On the inferior part of
the head we notice another articular facet,
planiform, situated internally, and generally con-
tinuous with the articular surface last described.
By means of this facet the astragalus moves
on a corresponding surface on the upper and
anterior part of the os calcis.

The head of the astragalus is connected to
the body by a narrow contracted portion called
the neck, which is rough on all its surfaces,
giving insertion to ligaments and perforated by
numerous foramina for the transmission of
vessels. The external side of the neck pre-
sents a remarkable excavation, which affords
insertion to and contributes to bound a space
fur the lodgement of a strong ligament which
passes between the astragalus and os calcis.

All that portion which is behind the neck
constitutes what is called the body, on which
we notice five surfaces, a. The superior sur-

face forms an articular trochlea, convex from
before backwards, and slightly concave trans-
versely; it articulates with the inferior extremity
of the tibia :* immediately in front of it there
is a roughness of very limited extent, which
affords insertion to ligamentous fibres, b. The
posterior surface is almost wholly occupied by
a well-marked groove, which passes obliquely
downwards and in wards, and is destined to lodge
the tendon of the flexor pollicis longus. c. The
external surface is occupied by a triangular
facet, whose base is direct upwards and is con-
tinuous with the articular part of the superior
surface of the body ; this facet articulates with
the fibula. It is bounded below and behind
by a rough portion for ligamentous insertion.
d. The internal surface is also articular in its
upper half for the adaptation of the inner
malleolus : it, too, is triangular, and by its
base is continuous with the superior surface.
Below this internal malleolar facet the bone is
rough and irregular, and here the internal
lateral ligament of the ankle-joint is inserted.
Lastly, the inferior surface is occupied almost
entirely by a concave articular facet, oval, with
its long axis directed from within outwards and
forwards ; this facet is articulated with a corre-
sponding one upon th» os calcis. Immediately
in front of it there is a deep and narrow depres-
sion which separates it from an oval planiform
facet for articulation with the sustentaculum of
the os calcis.

2. Os calcis (wrtqva, o-xeXi? ; Fr. le calca-
neum, os du talon; Germ, das Fersenbein ; the
heel-bone). — This is the largest bone of the
tarsus ; it occupies the most posterior part of
the foot, and is situated immediately under-
neath the astragalus, of which it constitutes the
principal support. Its greatest extent is from
before backwards. It is somewhat flattened on
the sides : its direction is horizontal, the foot
in standing resting upon the most posterior part
of its inferior surface. This horizontal direc-
tion of the heel-bone is one of the arguments
which anatomy affords in support of the asser-
tion that the erect posture is natural to man.

We notice six surfaces upon this bone.

a. The superior surface, or that upon which
the astralagus rests. On it we observe in front
three articular facets, separated from each other
by distinct intervals: the first or smallest is
situated at the anterior edge of the surface and
at its internal angle, and is articulated with the
facet on the inferior part of the head of the
astragalus ; it is not constant. The second is
posterior and internal to the last, separated
from it by a rough-depression about a quarter
of an inch in extent. This is oval, slightly con-
cave, and is marked upon a projecting portion
of the bone which overhangs the anterior part
of the internal surface, and which is known
under the name of processus interims, or sus-
tentaculum cervicis tali of Albinus ; it supports
and is articulated with a corresponding facet
on the under surface of the neck of the astra-
galus. A narrow groove on the outside of the

* See further description in the article ANKLK-
JOIKT.

z 2

340

BONES OF THE FOOT.

facet last named separates it from the third and
largest one ; this is articulated with the facet
\vhich is on the inferior surface of the body of
the astragalus ; it is oval, convex, and its long
axis directed forwards and outwards. Imme-
diately in front of this articular facet there is a
hollow, rough, non-articular surface for the
insertion of the ligament which connects the
astragalus to the os calcis, and behind the facet
the remaining portion of the superior surface
of the bone is also non-articular, slightly exca-
vated from before backwards, varying in length
in different subjects, and on this variety de-
pends the diversity in the length of the heel.
b. The posterior surface, oval in its outline,
rough and fibrous in its inferior half, where the
tendo Achillis is inserted, smooth in its supe-
rior half where a bursa is placed, over which
the tendon glides, c. The inferior or plantar
surface, nearly equal in extent to the superior,
and in the natural position directed obliquely
upward and forwards. Here we find, in ex-
amining the parts from behind forwards, first,
two tubercles, upon which the heel rests in
standing, and which seem peculiarly to cha-
racterize the human heel-bone. These tuber-
cles are separated from each other by a depres-
sion; the internal one is greatly the larger — it
affords attachment to the short flexor of the toes ;
the external one is small and pointed, and to it
are attached the abductor minimi digiti muscle
and the plantar fascia. Secondly, in front of
these tubercles the bone is very rough and flat to
within half an inch of its anterior margin,
where it is slightly grooved transversely. The
whole of this portion gives insertion to the
strong calcaneo-cuboid ligament, d. The ante-
rior or cuboid surface, which is entirely articu-
lar, triangular, with its base upwards, slightly
concave, and articulated with the cuboid bone.
e. The external surface, quite subcutaneous,
so that here the bone is greatly exposed to
injury, and may be easily got at for surgical
operation. It is slightly convex, its posterior
half being double the size of the anterior in ver-
tical measurement; at the anterior part of the
former there are two superficial grooves directed
obliquely forwards and downwards, separated
by a slightly prominent tubercle. The anterior
of these grooves gives passage to the tendon of
the peroneus brevis, the posterior to that of
the peroneus longus. f. The internal surface,
excavated in its whole extent, lodges the ten-
dons and nerves which are passing from the
back of the leg to the sole of the foot ; at the
junction of its anterior and posterior halves it
is overlapped by the sustentaculum, the inferior
surface of which is grooved by the tendon of
the long flexor of the great toe.

3. Os cuboideum, (os cubiforme, Fr. le cu-
boide, Germ, das Wurfelbein.)—T\ns bone
forms the external one of the second row of
tarsal bones ; it is situated between the os
calcis behind and the fourth and fifth meta-
tarsal bones in front ; in point of size it ranks
next to the astragalus. Six surfaces may be
described upon it. a. The superior or dorsal
surface, forming an inclined plane, directed
downwards and outwards ; it is rough for liga-

mentous insertion, b. The external surface,
more properly an edge, very limited in extent,
chiefly occupied by the commencement of the
groove for the peroneus longus muscle, c. The
inferior or plantar surface, which in front pre-
sents a deep groove directed obliquely forwards
and inwards, parallel to the anterior edge, and
destined to lodge the tendon of the peroneus
longus. The posterior edge of this groove is
very prominent, and with the remainder of this
surface, which is rough, affords insertion to
the calcaneo-cuboid ligament, d. The internal
surface has at its upper and posterior part a
triangular plane articular facet for articulation
with the external cuneiform bone, and some-
times a smaller one for articulation with the
navicular; the rest of this surface is irregular
and rough for ligamentous insertion, e. The
anterior or metatarsal surface is wholly arti-
cular, and is divided by a vertical line into two
facets, an outer one triangular and plane for
the fifth,- and an inner one quadrilateral and
very slightly concave for the fourth metatarsal
bone. The external of these facets is inclined
obliquely outwards and backwards, f. The
posterior surface is oval, with its long axis
directed downwards and outwards; it is wholly
articular and adapted to the anterior surface of
the os calcis.

4. Os scaphoideum (from 0->eap*j, navis, os
naviculare, Fr. le teapholde, Germ, das Kahnbein,
oder Sc/iiffbrrnige KnochenJ) forms the posterior
and internal bone of the second tarsal row, and
is placed between the three cuneiform bones in
front and the astragalus behind. It is oval in
shape, with its long axis directed obliquely
downwards and inwards; the small end of the
oval is situated internally and inferiorly, and
presents a distinct prominence or process (tuber
ossis navicularis), which gives insertion to some
fibres of the tendon of the tibialis posticus.

Four surfaces may be described upon this
bone. «. The superior or dorsal surface, of
great extent, convex, very rough for the inser-
tion of ligaments, and perforated by foramina.
b. The inferior surface, irregularly concave,
and very rough, also affording insertion to
ligaments, c. The posterior surface, entirely
articular, oval and concave, adapted to the
head of the astragalus, although considerably
less in extent than it. This constitutes what is
called the glenoid cavity, d. The anterior sur-
face, also articular and convex, divided by two
lines which converge from above downwards,
into three triangular surfaces for articulation
with the three cuneiform bones.

5. Ossa cuneiform ia (Fr. les os cuneiformes,
Germ, die Keilformigen Knoc/ten.) These
bones are interposed between the navicular
bone behind and the three internal metatarsal
bones in front ; they are arranged in the form
of an arch, of which the middle cuneiform is
the central or key-bone. Each is very distinctly
wedge-shaped; the two outer ones have the
acute edge directed downwards, but the inter-
nal one has it directed upwards.

The internal cuneiform bone is at once dis-
tinguishable from the others by its great size.
By means of an oval concave articular surface,

BONES OF THE FOOT.

341

whose long axis is vertical, it is articulated
with the anterior and internal part of the navi-
cular bone, and in front a large and irregular,
slightly concave articular facet adapts it to the
posterior extremity of the metatarsal bone of
the great toe. Its inner surface is convex and
rough for ligamentous insertion ; on it, towards
its anterior part, we observe an impression,
sometimes an eminence, for the insertion of
the tibialis anticus tendon; and its plantar
surface, the base of the wedge, is thick and
prominent, and affords insertion to ligamentous
fibres as well as to those of the tibialis posticus
tendon. The external surface is articulated in
front with the second metatarsal bone, and
behind with the middle cuneiform, by means
of an oblong articular facet, which extends
along the upper part of this surface from before
backwards parallel to the acute edge. The
remainder of the external surface is rough for
ligamentous insertion, excepting a small por-
tion about the sixth of an inch broad, which,
extending along the posterior edge, is articular
and continuous with the posterior surface of
the bone.

The middle or second cuneiform bone is the
smallest of the three ; its base is uppermost,
rough and convex ; its posterior surface is tri-
angular with the base superior; it is articular
and adapted to the middle facet on the anterior
surface of the navicular; its anterior surface is
also triangular and articulated with the second
metatarsal bone ; its inner surface is articular
along its upper and posterior edges, and rough
in the remainder of its extent; this surface is
in contact with the inner cuneiform. The outer
surface is articular along half of its upper edge
and the whole of its posterior, but rough in
the remainder, and by means of the articular
portions is connected with the external cunei-
form bone.

The external or third cuneiform bone is
second in point of size ; it is bounded on the
outside by the cuboid, behind by the navicular,
on the inside by the middle cuneiform, and in
front by the third metatarsal bone. Its pos-
terior and anterior surfaces are both plane and
articular, the one for the navicular, the other
for the third metatarsal bone. The base of the
wedge is situated on the dorsal surface of the
foot, and is rough. The internal surface
presents at its posterior edge a facet for arti-
culation with the middle cuneiform, and in
front another for the second metatarsal ; the re-
mainder is non-articular. The external surface
presents, towards its upper and posterior angle,
a plane triangular facet, which is adapted to a
similar one on the inner surface of the cuboid,
but in the rest of its extent it is rough and non-
articular.

Structure of the tarsal bones. — Like all the
short bones, those of the tarsus are composed
of a mass of spongy tissue surrounded by a
thin and papyraceous layer of compact. Hence
these bones are remarkable for their extreme
lightness.

Developement. — In the third month the
cartilaginous framework of these bones is
already apparent. The largest two begin to

ossify before birth ; the os calcis commences at
from the fifth to the seventh month, by a single
point of ossification situate about the middle of
the bone rather nearer to its anterior part, and the
ossification is not completed till eight or ten years
after birth, when another point appeal's in the
posterior part of the bone, and by the extension
of it to the first point, which is finished about
the fifteenth year, the process is completed.
The ossification of the astragalus commences
about the sixth month. The cuboid and navi-
cular begin to ossify immediately after birth
by one point each, and the three cuneiform
bones are ossified, the internal about the end
of the first year, die middle and external about
the fourth year.

II. Metatarsus (der Mittelfuss). — This seg-
ment of the foot is composed of five bones
placed parallel to each other in front of the
tarsus, with which their posterior extremities
are articulated. These bones are distinguished
numerically, counting from within outwards ;
a distinct interosseous space intervenes between
each pair of bones, which in the recent state is
filled by muscle. From the arched form of
the tarsus, the metatarsus naturally takes a
similar arrangement by reason of its articula-
tion with it, and consequently we observe that
it is convex on its dorsal surface and concave
on its plantar.

The raetatarsal bones possess certain general
characters in common; they belong to the class
of long bones, and consequently each has its
shaft and two extremities. The shaft in all is
prismatic, slightly curved, convex on the dor-
sal, concave on the plantar surface; two of the
surfaces of the shaft are lateral, and correspond
to interosseous spaces ; the third is superior,
and corresponds to the dorsum of the foot.

The posterior or tarsal extremity of each
metatarsal bone is wedge-shaped, the base of
the w:edge being on the dorsal aspect. Three
articular facets may be noticed on each, ex-
cepting the first and fifth. The posterior of
these is triangular and plane, articulated with
the tarsal bones ; the remaining two are lateral,
and adapted to corresponding ones on the
metatarsal bones on each side.

The anterior or digital extremity of each
metatarsal bone presents an articular head or
condyle, flattened upon the sides, oblong from
above downwards, and much more extended
inferiorly or in the direction of flexion than
superiorly or in that of extension. This is
articulated with the posterior extremity of the
metatarsal phalanx. On each side of the con-
dyle there is a depression, and behind that
an eminence to which the lateral ligament of
the metatarso-phalangeal joint is attached.

In addition to the characters above men-
tioned, there are certain special characters
belonging to particular metatarsal bones which
enable us to distinguish them from each
other.

The first, or metatarsal of the great toe, is
distinguished, 1. by its considerable size and
its being the shortest of the five bones; 2. its
tarsal extremity is semilunar and concave, and
has no lateral articular facet; 3. its digital

342

BONES OF THE FOOT.

extremity has on its plantar portion two con-
cavities separated by a ridge, with which the
sesamoid bones articulate. The second cha-
racteristic is one which peculiarly distinguishes
this bone.

The second is the longest ; it extends farther
backwards than any of the others, and is
lodged in a mortise-shaped cavity formed by
the three cuneiform bones.

The fifth has the following characters : — 1.
it is shorter than the second, third, and fourth ;
2. it has no lateral articular facet on the outer
side of its tarsal extremity ; 3. on this same side
it is prolonged backwards and outwards into
a long pyramidal process, which gives insertion
to the tendon of the peroneus brevis. This
process being quite subcutaneous, it is a useful
guide to surgeons in the partial amputation
of the foot at the tarso-metatarsal articulation.

The third and fourth resemble each other
very closely; the thud, however, is a little
longer than the fourth, and the posterior ar-
ticular facet on the fourth is more quadrangular
than triangular.

The structure of the metatarsal bones is that
of the long bones in general.

Developement • — Each metatarsal bone has
two points of ossification ; one for the body,
the other for the anterior extremity, except
in the case of the first, in which the second
ossific point is for the tarsal extremity. Be-
tween the third and fourth months the osseous
point of the body commences, and in the
full-developed fcetus the body is completely
ossified. In the course of the second year
the point for the extremity appears ; the epi-
physis of the first metatarsal bone is united
first, about the eighteenth year, and this union
precedes that of the others by about twelve
months.

Toes(Digiti pedis; Fr. les orteils ; Germ.
die Zehen). — The toes are numbered from the
inner or great toe; they gradually diminish in
length from the first to the fifth : the four
outer ones consist each of three portions or
phalanges; the great toe has only two. The
phalanges are best named from their relations,
viz. metatarsal, middle, and ungual.

The metatarsal phalanges are considerably
the longest. 1'he shaft in each is prismatic, like
that of the metatarsal bones, convex on the dor-
sal, concave on the plantar surface. On the pos-
terior extremity is a concave facet, articulated
with the anterior head or condyle of the cor-
responding metatarsal bone. The anterior ex-
tremity is less swollen than the posterior: it
is marked by an articular surface, which ex-
tends much more on the inferior surface than
the superior; this is concave transversely, but
convex from above downwards, and is arti-
culated with the posterior extremity of the
middle phalanx. All the metatarsal phalanges
possess these general characters: that of the
great toe is very considerably thicker than the
others, and is slightly longer; the remaining
ones differ but little in size : they progressively
diminish towards the fifth.

The middle phalanges are very short, but
possess pretty nearly the same general characters

as the metatarsal. The posterior extremities
are articulated with the last-named phalanges
by means of an articular surface, concave
from before backwards and convex transversely.
The articular surface on the anterior extremity
is convex. The great toe is deficient in the
middle phalanx; they diminish in size from
within and outwards. They have been com-
pared to the pieces of the coccyx, but may
be easily distinguished by the articular surfaces.

The ungual phalanges (so called from being
next the nail, unguis) are five in number,
and decrease in size from the first to the fifth ;
that belonging to the first very much exceeding
the rest in size. The posterior extremity of
each is expanded, and has an articular facet
for articulation with the middle phalanx. The
central part or shaft is flattened, slightly
convex on its dorsal surface : its anterior ex-
tremity is still more flattened and slightly
expanded, presenting a thin convex margin.
It is rough on its inferior surface where the
dense and adipose cellular tissue constituting
the pulp of the toe is connected with it, and
on its superior surface it is smooth, where
the nail is applied upon it.

The structure and mode of developement
of the phalanges are pretty much the same
as those of the metatarsal bones : their complete
ossification, however, takes place at a much
later period.

For the modifications in the number, forms,
and arrangement of the bones cf the foot in
the animal series, see OSSEOUS SYSTEM (Comp.
Anat.) and the articles on the various classes.

JOINTS OF THE FOOT. — These may be classed
as the joints of the tarsus, metatarsus, and
toes.

Joints of the tarsus. — The bones constituting
the first row of the tarsus are connected to-
gether by means of two articulations, one
posterior, the other anterior. The first (pos-
terior astragalo - calcanien articulation) is
formed by a convex oval surface on the os
calcis, which is received into a deep concavity
on the astragalus. A synovial sac lines these
surfaces; the posterior part of this sac is
covered by the fatty substance which is placed
between the back of the ankle-joint and the
tendo Achillis, and on the removal of the fat
the sac is observed to be strengthened, especially
in its centre, by a few ligamentous fibres.
On the inner side this sac is strengthened by
the tendon of the flexor pollicis proprius and
its sheath behind, and by the internal lateral
ligament of the ankle-joint in front ; both of
which very much protect the articulation and
strengthen the union of the bones. Anteriorly
there are no proper fibres applied upon the
synovial membrane; but the interosseous liga-
ment to be described presently, amply supplies
the want of them. On the outside a few
ligamentous fibres are applied to the synovial
membrane.

The anterior astragalo-calcanien articulation
is formed by a slightly convex surface on the
astragalus, which is received by a concavity
on the upper surface of the sustentaculum of
the os calcis. This articulation is furnished

BONES OF THE FOOT.

343

with a synovial membrane, which is only a
prolongation from that of the joint between
the astragalus and scaphoid.

The chief bond of union between the as-
tragalus and os calcis is by means of the
interusseous ligament (apparatus ligamentosus
cuvitatis sinuoste, Weitbr.): this ligament oc-
cupies the hollow which is manifest on the
outside between the os calcis and the neck
of the astragalus. It consists of a series
of strong ligamentous fibres, which arise all
along the inner part of the depression on the
astragalus in a curved course, and descend
vertically, or nearly so, to be inserted into
the corresponding depression between the two
articular surfaces on the os calcis. A con-
siderable quantity of fat occupies this space,
and covers this ligament, and is intermixed
with its fibres.

The bones forming the second row of the
tarsus are articulated as follows : —

The scaphoid or navicular bone is articulated
with the three cuneiform, by means of the
triple surface already described on the former
bone ; to each division of which one cuneiform
is adapted (cuneo-scaphoid articulation). A
common synovial membrane lines the surface on
the scaphoid, the surfaces of the cuneiform bones,
and passes in between them to line the lateral
articular facets on the latter bones. The three
cuneiform bones are connected to the navicular
by means of six ligaments, which pass from
the former to the latter; three on the dorsal
surface and three on the plantar. The dorsal
ligament of the internal cuneiform extends
directly from behind forwards, those of the
others proceed obliquely forwards and out-
wards. The internal cuneiform has likewise
an internal ligament, which proceeds from its
internal part directly backwards to the navi-
cular; it lies above" the tendon of the tibialis
posticus. As to the plantar ligaments, that
of the internal cuneiform is the strongest : it
is extended between the tubercle on the na-
vicular bone and that on the cuneiform, and
is in part confounded with the tendon of the
tibialis posticus, which sends a process out-
wards to the other cuneiform bones, and
strengthens the ligamentous fibres which belong
to them.

The cuneiform bones are articulated to each
other by means of the lateral facets, which
are lined by synovial membrane prolonged
from that of the cuneo-scaphoid articulation.
Each joint is strengthened by a dorsal, a
plantar, and an interosseous ligament. The two
former are extended transversely from one
cuneiform bone to the other, the dorsal being
considerably the stronger. The principal bond
of union, however, is by the interosseous liga-
ment, which is extended between the non-
articular parts of the lateral surfaces of each
cuneiform bone.

The cuboid bone is articulated with the
external cuneiform (cuboido-cuneen articula-
tion) in a manner so similar to that by which
the cuneiform bones are articulated with each
other as to render a separate description super-
fluous. Its synovial membrane is continuous

with that of the cuneo-scaphoid, and its liga-
ments are precisely similar to those of the
cuneiform articulations.

The cuboid bone is united to the scaphoid
by means of ligaments. The outer extremity
of the latter bone is in contact with a small
portion of the inner surface of the former, near
its posterior superior angle, and sometimes a
small articular facet indicates the point of each
bone where contact is established. The liga-
ments which pass between these bones under
all circumstances are & dorsal ligament, directed
obliquely from without inwards, a plantar
ligament, transverse and very thick, and an in-
terosseous ligament extended between the cor-
responding surfaces of the two bones, excepting
where the facets are found, when they exist.

Articulation of the two rows of tarsal bones
to each other. — This is effected by means of the
astragalus and os calcis behind, and the scaphoid
and cuboid in front.

Astragalo-scaphoid articulation. — The head
of the astragalus is received into a cavity which
is in greatest part formed by the glenoid cavity
of the scaphoid bone, and is completed infe-
riorly and internally by a ligament (the inferior
calcaneo-scaphoid), which extends from the
sustentaculum of the os calcis to the inner part
of the inferior surface of the scaphoid. On
the outer side and inferiorly the head of the
astragalus is supported by a short ligament
(the external calcaneo-scaphoid) which is at-
tached posteriorly to the inner part of the os
calcis, and in front to the external extremity of
the scaphoid. The extension of the recipient
cavity for the head of the astragalus by means
of the ligaments just named was rendered
necessary by the considerable excess in the size
of the head of the astragalus over the glenoid
cavity of the scaphoid. By means of these
ligaments, too, the os calcis is connected with
the scaphoid, although there is no articulation
between them.

The astragalo-scaphoid articulation is strength-
ened by but one proper ligament, and that is
situated in the dorsal aspect; it is the superior
astragalo-scaphoid ligament, and is attached
posteriorly to the neck of the astragalus, and in
front to the margin of the glenoid cavity; the
transverse extent of this ligament is equal to
that of the scaphoid bone on its dorsal surface;
the direction of its fibres is forwards and out-
wards. It is a thin fibrous expansion, covered
superiorly by the extensor brevis digitorum
muscle, and on its inferior surface lined by the
synovial membrane of the joint.

Calcaneo-cuboid articulation. — The articular
surface on the os calcis is slightly concave in
the direction from above downwards; that on
the cuboid is convex in the same direction.
The two surfaces are closely adapted to each
other, and their union maintained by the fol-
lowing ligaments : — 1 . The superior or dorsal
Cfilcaneo-cuboid ligament, which consists of but
a few fibres extending from the superior and
anterior part of the os calcis to the cuboid.
2. The internal calcaneo-cuboid ligament, a
short, strong, quadrilateral ligament from three
to four lines in breadth, placed m great part

344

BONES OF THE FOOT.

over the superior aspect of the joint; the fibres
pass with a slight obliquity inwards from the os
calcis to the cuboid. 3. The plantar or inferior
calcaneo-cuboid ligament, the strongest and
largest of the foot ligaments, seems destined
not alone for the articulation under considera-
tion, but also to strengthen the arch of the
tarsus generally on its plantar surface. It is
attached behind to the inferior surface of the
os calcis, commencing from the angular depres-
sion between the two tubercles. After leaving
the os calcis a distinction between its superficial
and deep fibres becomes very manifest; the
former proceed forwards and inwards, pass
under the cuboid bone, forming an adhesion to
the posterior lip of its groove, then pass under
that groove and its contained tendon, and are
ultimately inserted into the posterior extremities
of the third and fourth metatarsal bones. The
deep fibres diverge immediately after they have
left the os calcis, and are inserted into the whole
inferior surface of the cuboid posterior to the
groove.

It will be observed that the two joints last
described lie beside each other in the same
line, a circumstance which favours the surgical
operation of partial amputation of the foot in
that line. Each joint, however, has its proper
synovial membrane lining the cartilaginous
incrustations of the bones and the articular
surfaces of the ligaments; that of the astragalo-
scaphoid is the more lax, and indicates the
existence of a considerable range of motion in
that joint.

Motions of the tarsal joints. — All these
joints belong to the class Arthrodia, some of
them being planiform. The motion in all is
that of simple gliding, limited by the strength,
number, and position of the ligaments. The
close inspection of the bones of the meta-
tarsal row, and the firm ligamentous bands
which pass between them, occasion a very
limited mobility of the bones of that row.
Between the astragalus and os calcis, on the
other hand, the motions are much more mani-
fest; these are gliding motions in the direction
from before backwards and vice versa, or from
side to side. \\ hen the foot is turned inwards
or outwards the latter motion is called into
play, and the gliding in the antero-posterior
direction takes place when the weight of the
body presses on the foot, causing its elongation
and the diminution of the curvature of its
antero-posterior arch. When the weight presses,
the astragalus glides forward upon the os calcis;
when the weight is removed, the bone returns
to its firmer condition by gliding backwards.

But the greatest mobility exists in the articu-
lation between the two rows of tarsal bones.
There, indeed, the principal motions of the
tarsus take place. The motions of the foot,
which many have erroneously attributed to a
supposed power of lateral motion in the ankle-
joint, really take place in this line of articula-
tion. When the foot is turned so that its sole
is directed outwards, the scaphoid glides from
above downwards on the head of the astragalus,
the astragalus glides from within outwards on
the os calcis, in consequence of which the

hollow space between the last-named bone and
the neck of the astragalus is diminished, the
interosseous ligament relaxed, the external
lateral ligament of the ankle-joint likewise
relaxed, and the internal lateral ligament ren-
dered tense. On the other hand, when the
sole of the foot is turned inwards, which may
be done much more completely than in the
opposite direction, the scaphoid glides from
below upwards upon the head of the astragalus,
the inferior surface of the os calcis is turned
inwards, the astragalus glides upon the last-
named bone from without inwards, enlarging
the interosseous space, stretching the ligament
which occupies that space, arid also rendering
tense the external lateral ligaments of the ankle-
joint. It is therefore natural to expect, as
Bichat has remarked, that in those sprains
which result from too great inversion or eversion
of the foot, the ligaments of the articulations
between the tarsal rows should suffer most.

Tarso-metatarsal articulations. — The plane
surface on the wedge-shaped tarsal extremity of
each metatarsal bone is applied to correspond-
ing plane surfaces on the cuneiform bones and
the cuboid. The first, second, and third meta-
tarsal bones, counting from within outwards,
are articulated with the first, second, and third
cuneiforms, and the fourth and fifth with the
cuboid; the second metatarsal, however, is
additionally articulated with the first and third
cuneiforms, by its lateral surfaces being, as it
were, mortised into a cavity formed by these
three bones, and each of the other metatarsal
bones is articulated with its fellow on each side
of it. These articulations have the following
common characters : they are planiform arthro-
dise, each articular surface is covered by a thin
layer of cartilage, and they all have ligaments
similarly arranged in two sets, dorsal and
plantar.

The first tarso-metatarsal articulation has a
greater extent of its articular surfaces than those
of the others. Its plantar ligament is of great
strength and extends from the great cuneiform,
directed obliquely forwards and outwards to
the first metatarsal bone, continuous posteriorly
with the cuneo-scaphoid ligament, and strength-
ened by fibres from the tendon of the tibialis
posticus, and on the outside by fibres from the
tendon of the peroneus longus. The dorsal
ligament consists of short and parallel fibres ; its
breadth is equal to that of the cuneiform bone ;
it is a weak and membranous ligament. This
articulation has a synovial membrane distinct
from that of the other tarso-metatarsal joints.

The second tarso-metatarsal articulation is
the most solid of all, from the fact of the pos-
terior extremity of the metatarsal bone being
fitted into the mortise-shaped cavity formed by
the cuneiform bones. Its ligaments, it may
naturally be expected, are more complicated
than those of the other joints of this row ; thus
it has three dorsal ligaments, a middle one,
possessing common characters with those of the
other joints, proceeding directly from behind
forwards from the second cuneiform to the
second metatarsal bone; the others are ex-
tended, one from the internal cuneiform

BONES OF THE FOOT.

345

obliquely outwards to the second metatarsal,
the other from the third cuneiform obliquely
inwards to the same bone. We find, moreover.
two plantar ligaments, one short *nd direct,
passing from the second cuneiform bone to the
second metatarsal, the other much longer and
more oblique, coming from the first cuneiform.
Lastly, this articulation has an interosseous liga-
ment, which is extended from the lateral facet
on the external surface of the first cuneiform to
a corresponding one on the internal surface of
the second cuneiform.

Each of the remaining tarso-metatarsal arti-
culations has its dorsal ligaments, of which
those of the third and fourth are direct, and that
of the fifth is extended obliquely outwards
from the cuboid to the fifth metatarsal bone.
In all three, the place of plantar ligament is
supplied by the sheath of the long peroneal
tendon, and the fifth receives additional strength
from fibres given off from the tendon of the
peroneus brevis. In the third there is an
interosseous ligament between the third and
fourth metatarsal bones, and from the anterior
part of the external surface of the third cunei-
form to the fourth metatarsal.

The five tarso-metatarsal articulations have
four synovial membranes amongst them : the
first, as has already been mentioned, has a
distinct one ; the second lines the contiguous
surfaces of the first and second cuneiform bones,
and is prolonged over the mortise-shaped cavity
and the articular portions of the second meta-
tarsal. The third lines the articular portions
of the third cuneiform and third metatarsal,
and is prolonged on either side of the latter in
the form of two culs-de-sac into the space
between the latter bone and the second meta-
tarsal on the inside, and the fourth on the
outside. In fine, the fourth synovial membrane
is common to the fourth and fifth tarso-meta-
tarsal joints.

Mttatarsal articulations. — The four external
metatarsal bones are articulated with each other
by means of the contiguous articular facets on
the lateral surfaces of their posterior extremi-
ties. They are maintained in apposition by
interosseous ligaments which pass from one
metatarsal bone to the other, being inserted
into rough surfaces immediately above the
articular portion of each bone. Moreover,
these joints have dorsal and plantar ligaments,
which consist of ligamentous fibres directed
transversely from one bone to the other. The
plantar ligaments are considerably stronger and
thicker than the dorsal.

The anterior extremities of the five meta-
tarsal bones, although not articulated together
by surfaces which play upon each other, are
yet connected by a common transverse ligament
which passes from one bone to the other, being
attached to the plantar surface of each bone,
and covered by the sheaths of the flexor ten-
dons.

Metatarso-phalangeal articulations. — The
convex articular surface of the anterior extre-
mity of each metatarsal bone is adapted to the
concave surface on the posterior extremity of
each posterior or metatar^a! phalanx. A sepa-

rate synovial membrane lines the articular sur-
faces of each joint ; and two lateral ligaments,
one on either side, maintain the surfaces in
apposition. On the dorsal aspect each joint is
strengthened and protected by the extensor
tendons ; and on the plantar a strong, thick,
almost cartilaginous substance is extended
from the metatarsal bone to the phalanx. This
substance protects the joint inferiorly ; it is
grooved on its inferior surface, and contributes
to form the sheath for the flexor tendon, which
runs along the plantar surface of each toe.

The metatarso-phalangeal articulation of the
great toe presents some points of difference
from the others ; its surfaces are more exten-
sive, and on the plantar aspect the head of the
metatarsal bone has a pulley-like form, from
the existence of a ridge in its centre, on either
side of which there is a superficial depression :
each depression receives a sesamoid bone,
which, being formed in the substance of the
inferior ligament, thus contributes greatly to
strengthen the joint in this situation.

Articulations of the toes. — These are gin-
glymoid joints, all closely resembling each
other both in the forms of the articular surfaces,
and also in the bonds of union by which the
contiguity of these surfaces is maintained.
The articular surfaces are pulley-like ; an in-
ternal and an external lateral ligament belong to
each joint ; and the plantar aspect of each is
protected by a ligamentous structure similar to
that a'ready described in the metatarso-phalan-
geal joints'.

Motions of the metatarsal joints. — At the
tarsal extremities the metatarsal bones enjoy
but a very limited mobility in consequence of
the strong and compact manner in which they
are articulated with the tarsus ; their motions
consist in a very limited and scarcely percepti-
ble gliding upwards and downwards. At their
phalangeal extremities, however, the metatar-
sal bones are capable of a greater, although
still a very limited, degree of motion.

Motions of the metatarso-phalangeal joints.
— These are flexion and extension, with a slight
degree of lateral inclination or abduction and
adduction, and also, of course, circumduction
or the rapid succession of the preceding four.
The lateral motions are very limited, being
most manifest in the joint of the great toe.
Flexion is limited by the extensor tendon and
the superior fibres of the lateral ligaments ;
extension by the inferior fibres of the lateral
ligaments, by the inferior ligament, and by
the flexor tendon.

Motions of the phalangeal joints. — Flexion
and extension only are enjoyed by these joints,
the extent of which is principally controlled
by the lateral ligaments and by the due anta-
gonism of the flexor and extensor muscles.

Viewing the human foot as a whole, we
cannot fail to notice how admirably it is
adapted as an instrument of support, and for
the purposes of progression. For the former
end the solid and yet elastic mechanism of
the tarsus is mainly useful ; this part is placed
immediately under the tibia, which transmits
the weight of the body to the astragalus, the

346

BONES OF THE FOOT.

highest bone of the tarsus; from this bone,
again, the weight is transmitted to the os
calcis in the backward direction, and to the
anterior row of tarsal bones in front, where
the transverse extent of the tarsus is consider-
ably increased, in order to enlarge the basis of
support. It is worthy of remark that the
solidity of the anterior part of the tarsus is less
on its inner than on its outer side, the effect of
which is to increase the elasticity of the former
part without materially diminishing its strength.
The object of this arrangement appears to be ex-
plained by the observation that the weight of the
body is transmitted by the astragalus principally
to the inner side of the tarsus. It is toward the
inner side also that the concavity of the under
surface of the tarsus is most evident, by which
not only can the sole of the foot adapt itself
to the irregularities of surface to which it is
applied, but it is enabled to yield under the
superincumbent weight, and so to counteract
the effects of sudden concussion in walking,
leaping, &c.

In the foot anatomists have described two
arches as connected with its mechanical arrange-
ments. The first is best seen in a profile view
of the foot ; it is termed the antero-posterior
arch ; upon this arch we rest when the toes are
applied to the ground, the posterior extremity
of it being the heel, the anterior the balls of the
toes, and the astragalus resembling the key-
stone of the arch. The second is the transverse
arch, which may be most satisfactorily demon-
strated by a transverse section made along the
line of the cuneiform bones. The effect of the
constant and violent exercises of the foot to
which public dancers are accustomed is to in-
crease the mobility of the different parts of the
foot, to an extent which unfits it, in a great
measure, for its office as an instrument of sup-
port in standing or walking, as may be ob-
served, says Sir C. Bell, in any of the retired
dancers and old figurantes. By standing so
much on the toes, he adds, the human foot is
converted to something more resembling that
of a quadruped, where the heel never reaches
the ground, and where the paw is nothing more
than the phalanges of the toes.

The following considerations connected with
the human foot may be quoted as so many in-
dications that the erect attitude is natural to
man: 1. the articulation of the foot at right
angles with the leg; 2. the great comparative
size of the foot, contrasted with that of other
animals; 3. the great transverse extent of the
foot ; 4. the predominance of its solid parts,
the tarsus and metatarsus, over its moveable
part, the phalanges ; 5. the direction of the me-
tatarsal bone supporting the great toe ; its situa-
tion and want of mobility ; 6. the limited mo-
bility of the phalanges of the foot as compared
with those of the fingers ; 7. the horizontal po-
sition of the os calcis ;* the excess of its trans-

* " Even the Simiae and the bear," says Mr.
Lawrence, " have the end of the os calcis raised,
so that this bone begins to form an acute angle with
the leg; the dog, the cat, and other digitated
quadrupeds, even the elephant himself, do not rest
on the tarsus or carpus, but merely on the toes ;

verse extent at its posterior over that of its an-
terior part, and the developement of its tuber-
cles ; 8. the great strength and developement
of the calcaneo-cuboid ligament; 9. the early
ossification of the bones of the foot as compared
with those of the hand.

The extraordinary extent to which art can
modify the positions of the several bones, and
the form of the whole foot, is remarkably ex-
emplified in the case of the Chinese foot. It
is well known that, among other barbarities
practised on Chinese females, their feet are
from an early period subjected to the most
violent pressure, with the view of reducing them
to that diminutive size which is esteemed a
point of great beauty. Hence the anatomical
examination of a foot thus compressed is a
point of great interest, not alone to the physio-
logist, but also to the surgeon, as indicating
what properly applied force may do when em-
ployed at a sufficiently early period. An inte-
resting account of such an examination was
communicated in the year 1829 to the Royal
Society by Mr. Bransby Cooper, from whose
paper we extract the following statements.

The foot at first view had the appearance of
being congenitally deformed ; it was remarka-
bly short; from the heel to the great toe its
measurement did not exceed five inches ; it was
very much contracted in its transverse dimen-
sions, and the instep extremely high, being un-
usually convex not only from before backwards,
but also from side to side.

" The position of the os calcis," to use Mr.
B. Cooper's words, " is very remarkably altered:
instead of the posterior projection which usually
forms the heel, a straight line is preserved in
this direction, not deviating from the line of the
tibia; and the projecting point which forms in
an ordinary foot the most posterior process into
which the tendo Achillis is inserted, touches
the ground, and becomes the point d'appui for
sustaining the whole weight of the body. The
articular surface of the os calcis in connexion
with the cuboid bone is about half an inch an-
terior to and two inches above this point ;
while the astragalar joint is behind and some-
what below the calco-cuboidal articulation ;
consequently the direction of the os calcis, (in
its long axis,) instead of being from behind for-
wards, is from below upwards, with the slightest
possible inclination forwards. The most pro-
minent parts of the instep are the round head
of the astragalus and the cuboidal articulation
of the os calcis. From this the remaining
tarsal bones slope downwards at nearly a right-
angular inclination to join the metatarsal bones,
whose obliquity is still downwards, until they
rest on their phalangeal extremities."

The points of support are the os calcis, the
anterior extremity of the metatarsal bone of the
great toe, and the dorsal surface of the fourth
and fifth toes, which are bent under the foot so
as to press the ground at this part.

(R. B. Todd.)

the cloven-hoofed ruminants and the Solipeda touch
the ground merely with the extremities of the third
phalanges, and the os calcis is raised nearly into a
perpendicular position."

ABNORMAL CONDITIONS OF THE FOOT.

347

FOOT, ABNORMAL CONDITIONS OF
THE. — The dislocation of any of the bones of
the foot is an accident of.unfrequent occur-
rence, particularly of the tarsus and metatarsus,
where the ligaments are powerful, and the joints
very limited in their motions. \Vhen a dis-
placement does occur here, the violence neces-
sary to produce it is often so great, that the
foot is destroyed . Cases, however, are met with
where a dislocation of one or more of these
bones has been successfully treated without loss
of the limb. Sir A. Cooper mentions several
instances. The astragalus alone, without the
other bones of the foot, is never thrown back-
wards, nor is it ever thrown directly inwards
nor directly outwards, but it may be dislocated
forwards on the instep and then may incline
inwards, so as to be situated below and in front
of the inner malleolus, or it may incline out-
wards and be placed below and in front of the
outer malleolus ; the rest of the foot in the
latter case is thrown inwards, and in the former
outwards.

In these cases there is what Boyer calls a
double luxation of the astragalus, for this bone
is not only expelled by violence from the mor-
tise-shaped cavity formed for it by the bones
of the leg, but is at the same time driven from
the space formed between the os calcis and os
naviculare, where it naturally rests or plays in
standing or progression.

Most of the ligamenlary ties which bind it
to the other bones of the foot and leg are vio-
lently ruptured, yet in these cases the surgeon
almost invariably finds great difficulty in ex-
tracting the bone from its new situation, and to
return it back to its original space in general is
quite impracticable.

One reason for the difficulty the surgeon
experiences in replacing the luxated astragalus
may, we imagine, be found in this, that the
bones once expelled by violence, the muscles
attached to the tendo Achillis, and, indeed,
all those of the leg before and behind, act so
on the foot as to have a powerful and effective
influence in effacing the interspace between the
os calcis and articulating surfaces of the tibia
and fibula, so that there is now no room for
its return.

Moreover, it should be recollected that the
astragalus is sometimes only partially luxated,
and perhaps at the same time has revolved on
its long axis in such a way that it shall be
placed as it were on its side, as we have known
an example, in which the pulley-shaped sur-
face of the astragalus looked outwards, the
peroneal articular surface looked downwards
towards the os calcis, and the facet for arti-
culation with the tibial malleolus was placed
upwards in contact with that part of the tibia
which was naturally shaped for articulation with
the upper part of the trochlea of the astra-
galus : when the astragalus is thus rotated on
its longitudinal axis, a broader part of the bone
is wedged in between the tibia and os calcis
than the vertical height of the astragalus would
measure, and hence there is difficulty in re-
storing the bone or removing it. Fig. 161 re-
presents the simple dislocation. More than

Fig. 161.

one example is mentioned by Sir A. Cooper
in which this bone was removed entire after a
compound dislocation of it, and yet a very
tolerable use of the foot was regained.

A heavy weight falling upon the foot will
sometimes displace the double articulation be-
tween the first and second row of tarsal bones.
When this accident has occurred, the appear-
ance which the limb assumes bears a striking
resemblance to the internal variety of the club-
foot. In fact this state of the parts really con-
stitutes neither more nor less than the pied-bot,
with the exception of the difference of the
cause, the state of ligamentous connections,
and the facility of reduction.

Dislocation of the other tarsal bones is very
rare, yet Sir A. Cooper has seen the inner
cuneiform bone displaced in two instances, in
neither of which could the bones be reduced.
See also Diet, des Sciences Medicales, art.
Pied.

The joints of the toes, as they are more
moveable and their ligaments more lax, are
more easily dislocated than the other joints of
the foot, and especially the great toe, which
has more extent of motion than the rest, and is
more exposed to the influence of accident.

Congenital displacement of the bones of the

348

ABNORMAL CONDITIONS OF THE FOOT.

foot is by no means an uncommon occurrence,
and though in our English systematic works
on surgery this case has met with little notice,
yet, as a subject of great importance to the
comfort and well-being of a numerous class of
sufferers, it is by no means undeserving of a

Elace in a professed work on surgery. As,
owever, the scope of the present is not strictly
surgical, we shall, in this article, content our-
selves with a pathological description of the
principal varieties of these deformities, and in
doing this we shall freely avail ourselves of the
assistance of an able article on the " Pied-bot,"
by Bouvier, in the Diet, de Medecine et de
Chirurgie Pratiques.

The ankle-joint is not generally implicated
in congenital deformities of the foot ; displace-
ment of the bones may occur to an extreme
degree, and yet the natural form and functions

of the ankle remain. But this rule is by no
means universal. The ankle-joint may be the
sole seat of the unnatural condition, or it may
share it in common with the bones of the foot;
but these cases are rare, they form only the ex-
ception to the general rule. There are three
principal forms of distortion to which the foot
is congenitally subject : 1. when the foot is
turned inwards, which has been termed varus:

2. when it is turned outwards, called valgus:

3. when the foot is permanently extended,
and the patient can only put the toes to the
ground, termed pes equinus. Almost all the
varieties of club-foot may be referred to one of
these species.

1. When the foot is turned inwards, (varus,)
the following modifications in the form of the
parts present themselves. (See Jigs. 162, 163.)
The dorsum faces forwards, the sole is turned

Fig. 162, 163.

backwards, and very considerably curved upon
itself. The inner side of the foot is uppermost,
the outer side rests upon the ground, the heel
is more or less turned inwards and upwards.
The integuments of the outer side are thickened
by pressure, and there is a sort of provisional
cushion, of a somewhat elastic nature, formed
under it, while the thickness and hardness of
the integuments of the sole are not found to
the usual degree. The joints that suffer most
in this malformation are, as might be expected
from a review of their natural structure, the
double articulations between the first and second
row of tarsal bones. The scaphoid bone is
twisted inwards in such a manner, that the
dorsum of it presents forwards and its apex
backwards, and the navicular cavity is brought
to the inner edge of the astragalus. The cuboid
bone generally preserves its relation to the
scaphoid, being more or less displaced from
the os calcis, and turned under the foot. The
cuneiform bones, the metatarsus, and toes, are
little altered in their relation to those tarsal
bones to which they join, the peculiarity of
their position and direction being entirely the
result of the alterations in the scaphoid and

cuboid, just mentioned. The os calcis is
turned, so that its outer side is inclined to-
wards the ground, and further than natural
from the outer malleolus; the inner hollow side
is inclined upwards and inwards, and nearer to
the inner malleolus than natural, and the heel
itself is elevated. By this means the articula-
tions between this bone and the astragalus are
altered somewhat, particularly if the ankle-joint
itself remains natural, the astragalus not having
partaken of the general malposition ; this bone
is then thrown in some degree upon the outer
side of the os calcis. The astragalus, we have
said, rarely shares in the general deformity ;
when it does it is tilted outwards, so that its
upper surface inclines towards the external
malleolus, and the articular portion itself be-
comes altered in form, as is also the corre-
sponding portion of the tibia ; in one instance re-
lated by Bouvier, the astragalus, by the pressure
of the inner side of the tibia above and of the
calcis below, was reduced to a mere thin edge
on this side, the whole bone being something
in form of a wedge between them.

2. In the valgus, (see Jig. 164), where the
foot is turned in the opposite direction to that

ABNORMAL CONDITIONS OF THE FOOT.

349

Fig. 164.

which has been just described, the whole state
of the foot seems to be pretty nearly the exact
converse of every thing there mentioned. The
same bones are affected, and in the same rela-
tive degree ; and the same analogy which exists
between the one condition and the phenomena
of adduction, is found between the other and
those of abduction. The dorsura faces more
or less directly forwards, the plantar surface
backwards, the inner side of the foot rests upon
the ground, the outer is uppermost. The tibia
frequently here participates in the deformity so
far as to have a curve inwards, and the inner
ankle consequently approaches to the ground.
The double articulation between the first and
second row of bones in this case also suffers
the most. The astragalus sometimes projects
in front, and lower than in the varus. The
distortion is sometimes carried to such an ex-
tent that the foot is

Fig. 165.

turned nearly upwards
and at the side of the
fibula. The os calcis
is twisted outwards,
with the heel elevated,
its hollow inclining to-
wards the ground. The
scaphoid and cuboid
bones are, as we have
said, most displaced;
the first being nearest
the ground, the last
placed uppermost, and
near the outer malleo-
lus. The cuneiform
bones, and the other
bones of the foot, retain
their relation to the
bones to which they
are articulated, their
unnatural situation be-
ing the result of the
displacement of these.
3. The pes equinus,
(see^g.165,) so named
from the resemblance in
the position of the tar-
sus to that of the horse,

differs from either of the others in its anato-
mical characters. When it has arrived at a con-
siderable pitch, the tibia is found partially dislo-
cated backwards upon the os calcis ; the sca-
phoid and cuboid are carried backwards, to-
wards the sole of the foot, leaving the upper
part of the head of the astragalus and cuboides
projecting; the cuneiform and metatarsal bones
are displaced sometimes in a similar manner.
Thus the whole foot is more arched than
natural, independently of its altered position ;
the sole is shortened and hollowed, the dorsum
is elongated and projecting.

A very interesting history of yet another form
of this disease by M. Holz of Strasburg, is
given in the 13th vol. of the Lancet, in which
the foot was turned completely back, having
the dorsum resting on the ground, the plantar
surface being uppermost. The deformity was in
both feet. Walking was not painful ; the patient
rested his weight on the tarsus ; the metatarsus
and toes did not touch the ground. He wore
common half-boots, the toes of which pointed
backwards and the heels forwards. The man
died, and upon examination of his feet the fol-
lowing state of parts was found. The skin of
the dorsum upon which he trod was hard and
callous. The bones of the leg were well
formed ; the astragalus was dislocated forwards;
the calcaneum forwards and outwards, and the
cuboid downwards on the calcaneum. The
dorsal surface of the foot was very convex, ex-
cepting at the spot which touched the ground ;
the plantar surface very concave. The supe-
rior articular surface of the astragalus was
turned directly forward and a little downward ;
its posterior surface also looked forward, and
the tibia rested on the inferior, in a great de-
gree, and on the small process of the calca-
neum. The connexion of the scaphoid with
the astragalus was more natural ; the scaphoid
was, however, turned a little backward. The
cuboid rested by its posterior part on the inferior
surface of the os calcis. The articular surfaces
of the astragalus and os calcis gave attachment
to ligamentous fibres. The three cuneiform
bones, the metatarsal bones, and the toes had
not experienced any sensible change in their
position.

The descriptions now given are of extreme
cases in each of the species of deformity. Of
course the degree of departure from the natural
form varies in every case. In the varus, every
intermediate shade between the extreme men-
tioned and the mere state of permanent adduc-
tion occurs. The state of fixed abduction may,
in the same way, be called the milder extreme
of the valgus, while the pes equinus shows its
simplest form in the mere fixed extension of
the foot.

We also find in some instances a combina-
tion of more than one form of the deformity in
the same foot. The most frequent of these is the
state of permanent extension, of the pes equinus,
with the adduction of the metatarsal bones and
phalanges, constituting a variety of the varus.
(Fig. 166.) The same complication of the
pes equinus with the valgus is rare, but does
sometimes occur, A congenital deformity, so

350

ABNORMAL CONDITIONS OF THE FOOT.

not

far as we know
mentioned, has once
fallen under our no-
tice, namely, a dislo-
cation of the tibia back-
wards upon the upper
and posterior part of
the os calcis, so that the
prominence of the heel
was entirely lost, and
the foot flexed to such
a degree, as that the
dorsum lay in contact
with the anterior part
of the leg.

The alterations from
the normal state of the
ligaments, bones, mus-
cles, and articular sur-
faces, in these cases of
deformity, are easily
comprehended. The
ligaments are of course
elongated on the one
side of the dislocated
joint, and shortened on

the other side ; the bones are altered in shape,
occasionally, where pressure is produced by a
neighbouring bone, and sometimes a portion of
the bone is twisted, and drawn towards the unna-
tural situation of that one with which it articulates.
The muscles are elongated or shortened, accord-
ing as their points of attachment are, by the
deformity, approximated or further separated.
The articular surfaces undergo great alterations :
they are altered in shape and situation by the
friction of the parts in contact producing a new
synovial surface upon its new situation, while a
part, or the whole of the natural joint loses its
polished surface, and becomes adherent to the
integuments, while, in many instances, the
altered position of a bone brings it into contact
with another, with which naturally it had no
such relation, and here again a preternatural
synovial articulation will form, in accordance
with the same law of the animal economy, by
which long-continued pressure will produce a
synovial bursa. As a general observation, we
may state, that the whole limb is smaller,
shorter, and feebler than the sound one, and
that this defect increases by comparison with
the sound one, as the child grows. M. Cru-
veilhier has also found that individual bones
are sometimes singly defective in their growth,
while occasionally only the portion of a bone
which is subjected to pressure is checked in
its developement.

The deformities described above are gene-
rally congenital, but they are also occasionally
produced after birth by accidental causes;
though/in this case there is no difference in the
nature of the distortion or in the anatomical
condition of the parts, yet they are less fre-
quently cured, because the same carelessness
or bad management which has too often occa-
sioned the accidental form of the disease to
creep on unheeded, makes the parents indiffe-
rent as to the cure, while the deformity, which
has not mismanagement for its cause, is imme-

diately remarked on the birth of the child,
excites alarm in the mind of the parent, and
means are early adopted for its removal.

This part of our subject leads us to notice a
deformity, of not uncommon occurrence, but
one which has met with little notice from
writers, although the inconvenience and suffer-
ing occasioned by it, great in degree, and, as
far as we have known, permanent in duration,
will entitle it to the consideration of the sur-
geon. We allude to that state of the foot
wherein the arch is lost, and the foot rests flat
upon the ground. It is met with generally,
but not always, in those children of the lower
classes who are obliged, in their early youth,
to engage in laborious occupations, and parti-
cularly in lifting heavy weights, before the
powers of the system are developed, though
we have known it to occur where none of these
causes could be traced. It happens generally,
not in the very weak, nor in the firm and robust
children, but in those who have the promise of
developement on a large scale, and are rapidly
growing. It comes on insidiously, and is
rarely detected until too far gone to admit of a
complete cure. The marks of this disease are
an evident alteration in the shape of the foot.
The dorsum has comparatively lost its con-
vexity, the concavity of the sole is entirely
gone ; the scaphoid bone projecting below un-
naturally, and the inner malleolus falling con-
siderably inwards. The relative position of all
the rest of the foot appears natural. The pa-
tient complains of pain and tightness at the
upper part of the instep passing through to the
sole upon attempting to elevate the heel while
standing. Indeed, in aggravated cases, he
cannot lift himself at all upon the metatarsus,
while every step upon an uneven surface is
accompanied with pain. The anatomical cha-
racters of this distressing disease consist, as far
as a close examination of the living parts can
detect, for we have had no opportunity of dis-
secting them, in a relaxation of that ligament
which passes between the os calcis and navicu-
lar bone, and on which the fore part of the
astragalus rests and moves. It will be quite
evident, from an examination of these parts
and their connexions, that this supposition is
sufficient, to account for the symptoms that are
apparent, and the idea is borne out by the fact
of the point of the scaphoid being further sepa-
rated than natural from the tubercle of the os
calcis, which may be readily ascertained by the
touch. We conceive the remote cause to be a
certain degree of inflammatory action in the
elastic ligament just mentioned, produced by
over-exertion, before the part had acquired its
full developement and strength. The morbid
action being continued by the continuance of
the irritation, the elasticity of the ligament is
impaired, and it can no more support the
weight laid upon it; it consequently yields,
and is stretched. This view receives some
support from the fact of the tenderness upon
pressure constantly found in this precise spot,
and from the relief afforded to the more dis-
tressing symptoms by the application of leeches
and counter-irritations.

REGIONS OF THE FOOT.

351

Another deformity of the foot occasionally
met with is exactly the reverse of the prece-
ding; this is too great a convexity of the arch,
by which the foot is considerably shortened,
and the bearing, anteriorly, taken from the
under side of the heads of the metatarsal bones,
and thrown partly upon the bases of the first
phalanges and upon the metatarso-phalangeal
joint itself. From the tense state of the plantar
fascia we must suppose that this structure is
shortened, and indeed we have been inclined
to consider this contraction of the fascia as in
some degree a cause of the deformity, which
Dupuytren has proved to be the fact in the
parallel case of contraction of the fingers, by
shortening of the palmar fascia. With this
view, in a case of deformed foot which lately
came under our notice, we divided the fascia
plantaris, and certainly with considerable tem-
porary benefit. We 'have not been able to
ascertain why the relief was not permanent, as
the patient lives at a distance; but it might not
improbably arise from his returning to work
too soon, and leaving off the extension of the
foot which had been adopted.

(A.T.S Dodd.J

FOOT, REGIONS OF THE.— The sur-
gical anatomy of the ankle having already been
given, (see ANKLE, REGIONS OF,) it remains
for us, in this article, to describe the foot pro-
perly so called, that is, all of the lower extremity
beyond the ankle. This part comprises much
that is practically interesting and important,
both in its pathology and surgery, which must
be evident when we consider the vast number
of ills which are endured in the feet. The
foot, considered as an entire region, is na-
turally and obviously subdivided into dorsal
and plantar regions. In the first of these
we observe, 1st, the dorsum, or instep, ex-
tending from the front of the ankle to the
heads of the metatarsal bones ; 2d, the toes
themselves.

I. Region of the dorsum. — We see the instep
falling, with a gentle curve, forwards from the
ankle, and forming the anterior portion of that
arch, which posteriorly runs through the ankle-
joint to the heel, and the crown of which, formed
by the astragalus, bears the weight of the whole
body. This most remarkable provision for
the safety and efficiency of the body is well
deserving of particular examination, and we
shall return to it when describing the plantar
region. The curve of the dorsum just men-
tioned is running forwards to the head of the
metatarsal bone of the great toe; there is
another arch, a lateral one, running across the
foot, of which the inner end is abrupt, as it
bends over the inner side of the ossa naviculare
and cuneiforme interna ; the outer end slopes
off more gradually to the os cuboides and
metatarsal bone of the little toe. The use
of this arch is best seen also in the sole,
though it presents itself to the view most
strikingly on the dorsum.

The principal points which claim our atten-
tion in this region are : —

1. The integuments, which are here rather

thinner and softer than in other parts of the
limb, but varying considerably in texture ac-
cording to age, sex, and habit: they are also
rather thinner on the outer than on the inner
side. 2. The subcutaneous cellular tissue.
This is rather loose, and freer from fat than
in other parts of the body, permitting free
movement of the superficial parts upon those
beneath. This laxity of the cellular tissue is
greatest on the middle of the instep ; and
accordingly we see in children and females,
where there is a large quantity of superficial fat,
and in effusions of water or other fluids, that
the skin of this part rises most, while across
the ankle and the roots of the toes there is
an appearance like a ligature arising from the
comparative closeness and shortness of this
cellular web. In this layer also we find
several large veins and some branches of
nerves. The dorsal veins of the foot run in
very irregular directions, varying in size in
different subjects, but mostly collected into
two plexuses, which form in front of the inner
and outer ankles, the saphena major and minor
veins. The course of these veins, though
various, is generally as follows : — The saphena
major begins to shew itself pretty conspicuously
on the middle and inner side of the instep,
and running to the inner ankle receives in its
course numerous additions, and then passes
over the internal malleolus. The saphena
minor is seldom found in a notable trunk
on the fool ; we see only on the outer side
of the dorsum several small branches commu-
nicating with the inner plexus, and taking
their course towards the outer ankle ; there
they form sometimes one, but generally
two branches, which pass sometimes over,
generally behind the outer malleolus. It is
the first of these veins that is principally im-
portant in s'urgery, as it occasionally, and we
think it might with advantage be more fre-
quently, opened for the detraction of blood.
It is immediately brought into view by a
ligature placed above the ankle, and in opening
it we must bear in mind that, from its super-
ficial situation, from the looseness of the en-
veloping tissue, and from the greater distance
of the ligature from the point to be punctured,
the vein is much more liable to roll and to
foil our attempts than the vein at the elbow :
we must, therefore, take the precaution of
putting the fore-finger above, and the thumb
below the spot where the lancet is to enter,
which will retain with facility the vein in its
place.

The varicose distention to which the trunks
of the saphena veins in the leg are peculiarly
liable, is often found extending to their minute
commencing branches on the dorsum of the
foot ; so much so that the whole of this region
is irregularly distended, and covered with the
knots and ramifications of the distended veins.
This morbid state is dependent upon the same
causes as the varicose affection of the veins
of the leg, and can be remedied only by the
same means, but with this additional disad-
vantage, that the mechanical means adopted
for their relief by pressure, owing to the more

352

REGIONS OF THE FOOT.

conical form of the foot, can with greater
difficulty be retained.

Besides the veins, we find imbedded in this
same layer of cellular tissue a number of
nervous filaments, which should be remem-
bered as occasionally interfering with operations
on this part. The last portion of the saphenus
or long cutaneous nerve runs so near to the
saphena major vein that some of its twigs
pass in front of and some behind it, and
have been occasionally punctured in opening
this vein ; but this should form no stronger
an objection to this operation than a similar
arrangement of the nerves, and a similar
accident in bleeding, which occasionally hap-
pens, should be allowed as an objection to
venesection at the bend of the arm.

3. The next layer brought into view by
dissection is a thin expansion of fascia, con-
tinuous with the anterior annular ligament of
the ankle, and formed of fibres running in
various directions, principally transverse and
spreading over the whole of the dorsal region,
but principally at the upper part. The ob-
servations which have been made on this same
fascia when covering the ankle may be applied
also to the part just described, (see ANKLE-
JOINT, REGION OF,) with this exception, that
as the dorsal fascia is much thinner and more
incomplete than that over the ankle, matter
would here not be so tightly bound down, nor
would it present so strong an obstacle to the
pointing of it outward.

4. On removing the layer of aponeurosis
a muscular and tendinous stratum is exposed,
comprehending the entire muscle of the ex-
tensor brevis digitorum and the tendons of
several of the long muscles situated on the
leg. The first of these has a thick fleshy
belly, and occupies the outer part of the
dorsum of the foot, sending its tendons down,
like so many rays, to the bases of the toes.
The tendons are spread over the foot in the
following order : — on the inner side the tibialis
anticus passing to be inserted, by a broad
attachment, into the internal cuneiform bone
and base of the first metatarsal bone ; next
the extensor proprius pollicis runs forwards
and inwards, along the fibular edge of the
first metatarsal bone; then the tendons of the
extensor longus digitorum run diverging to-
wards the bases of the four outer toes, crossing
over the tendons of the extensor brevis ; and
lastly, the tendon of the peroneus tertius,
diverging from the extensor longus, sends its
small flat tendon to the base of the fifth me-
tatarsal bone. Each of these tendons runs
in its own synovial sheath, and these are,
from their superficial situation and from their
proximity to the bones over which they pass,
peculiarly liable to be affected by pressure,
as from tight boots. The consequence of this
is not unfrequently seen in a small round
swelling, situated generally over the tarsal
bones, and upon one of the tendons of the
extensor digitorum longus. It is first dis-
covered generally by its tenderness, and when
this is relieved by taking off the pressure
which was its first cause, the swelling itself

still remains, soft and elastic to the touch,
and having all the characters of an enlarged
bursa, and which has received the name of
ganglion. The cure may generally be accom-
plished easily and expeditiously : a smart blow
with some hard body, as the back of a book,
while the swelling is rendered tense by the
forcible extension of the foot, will be all that
is necessary; the cyst is thus burst, and its
synovial contents, when extravasated among
the adjacent cellular tissue, soon become ab-
sorbed, while the empty cyst itself shrinks
and contracts to its natural size. Should,
however, this plan not be approved, or, which
may happen, not succeed, the introduction of
a cataract needle in an oblique direction under
the skin, and the puncture of the cyst, will
evacuate the fluid into the surrounding cellular
tissue, and thus effect a cure.*

A tumour is sometimes formed upon the
instep, which is also the result of pressure,
and which bears a near relation to a corn.
It is met with in young men who wear tight
boots, and the usual situation of it is over
the articulation between the internal cuneiform
bone and the metatarsal bone of the great toe.
The tumour is under the skin, hard and im-
movable ; so that it seems to a superficial
observer to be an enlargement of the bone
itself. The skin over it is in a natural state,
except in cases of long standing, in which
the cuticle becomes thickened. This swelling
is described by Sir B. Brodie in a clinical
lecture in the Medical Gazette, vol. xvii.
He is uncertain in what precise situation this
tumour exists, whether in the ligaments of the
joint, or periosteum, or in the ultimate fibres
of the tendon of the tibialis anticus muscle,
not having had an opportunity of dissecting it.

In this view also are exposed the course and
situation of the dorsal artery of the foot. This,
which is merely the continuation of the anterior
tibial artery, commences its course from the
anterior annular ligament of the ankle, a little
to the inner side of the middle of the foot;
from thence it runs obliquely towards the
first interosseal space of the metatarsal bones,
at the commencement of which it dips into
the sole of the foot, leaving only a branch to
continue its course to the great toe. In the
course just mentioned this artery rests upon
the bones of the tarsus, separated from them
and their ligaments only by a small quantity
of cellular tissue. It is accompanied by its
vein and a branch of a nerve, and will readily
be found running along the outer or fibular
edge of the tendon of the extensor proprius
pollicis, which partly overlaps it. Notwith-
standing the superficial situation of this artery,
its close connexion with the above-mentioned
tendon renders it peculiarly ineligible for the
application of a ligature, and fortunately it is
very rarely that we are called upon to perform
an operation upon it; but its course and
situation are important to the surgeon, as afford-
ing a valuable diagnostic mark, negative at

* See a paper on Ganglion by C. A. Key, Esq.
in the 1st vol. of Guy's Hospital Reports.

REGIONS OF THE FOOT.

853

least, if not positive, in the examination of
an injury to some of the larger vessels, as the
femoral or the anterior tibial. For though,
owing to occasional varieties in the course and
distribution of the dorsal arteries of the foot,
the absence of pulsation in the situation of
the arteria dorsalis pedis, just indicated, would
not be a positive proof of injury to the larger
vessels, (though even this might be received
as valuable corroborative evidence,) yet the
clear and full pulsation of this vessel would
of course be undoubted evidence that the
larger arteries were safe and sound. (See
TIBIAL ARTERIES.)

II. Region of the toes. — In the natural state
the toes are covered by a skin, soft and pliable,
except the extreme phalanx, the dorsal surface
of which is defended by the nail, for the struc-
ture and arrangement of which we refer to
the article TEGUMENTARY SYSTEM. Under
the skin and subcutaneous tissue we find the
tendon of the long extensor, lying close upon
the bone adhering to it and to the synovial
membranes of the joints, by short but free
cellular tissue, sufficiently loose to allow of
the free movements of the subjacent joints.
We observe that the length of the toes, by
the construction of the bones, much shorter
and smaller than the fingers, appears shorter
still in the metatarsal phalanx by the greater
depth of the integu mental web between the
toes. The operator will do well to remember
this in amputating at the metatarso-phalangeal
joint, or he will surely be foiled in his attempt
to open it, particularly as this joint, lying
deeper and being composed of smaller bones
than the corresponding joint of the hand, is
much less readily perceptible, even to the
touch. Lastly, these organs, the toes, more
universally, and in greater degree perhaps than
any other part of the body, pay the penalty
of hyper-refinement and civilization in the
distortion and disfigurement of their entire
structure from pressure. The skin suffers most
acutely; it becomes entirely altered in struc-
ture. The soft cuticle which covered it is,
by the irritation of pressure, increased in thick-
ness by successive additional layers. This
increase is greatest just at the point where
there is most pressure, namely, at the upper
and lateral parts of the projecting joints ;
nature thus providing a defence for the tender
cutis, pressed between the bone and the shoe.
The cause of irritation being still continued,
the defence itself is converted into an ad-
ditional enemy ; the accumulated layers of
hardened cuticle form a hard corn, and irritate
and inflame the subjacent cutis. Another
effort of nature is made to relieve the suffering
parts ; a small bursa is formed under the
most prominent part of the corn, and this
again is made an additional cause of suffering
by this part also becoming inflamed, the original
source of evil not being removed. The same
process taking place between the toes by the
pressure of one toe against the other, produces
the soft corn by the moisture of this part not
allowing the thickened cuticle to become hard
and dry. The same process on a larger scale

VOL. ir.

over the joints of the great toe occasions the
bunion,* the bursal cysts of which form a
beautiful illustration of the powers of nature
in accommodating herself to accidental circum-
stances.

Nor is the mischief arising from this oppo-
sition to nature confined to the results now
mentioned. The toes, from being constantly
kept in a distorted position, acquire perma-
nently an unnatural form, sometimes being
bent laterally under or over each other, the
ligaments become stretched, the articular car-
tilages absorbed, the ends of the bones altered
in form, and anchylosis is not unfrequently
the result. If the shoe be too short, a per-
manent contraction of the joint of the toe is
produced, which is sometimes so distressing
in walking as to be a serious impediment to
this exercise, and even to demand amputation
of the toe as the only means of deliverance.
This, when it does occur, is almost always
found in the second toe, because it projects
beyond the others.

Plantar region. — The plantar region, like
the dorsal, may be divided into the plantar
region, strictly so called, and the region of
the toes.

I. Proper plantar region. — The skin upon
the sole of the foot is covered by a cuticle
remarkable both for its general density and for
the great difference of its density in different
parts. In the hollow of the sole it is thinnest,
next along the outer side, and thickest of all
under the heel and heads of the metatarsal
bones. This great thickness of the cuticle,
though partly arising from pressure, is yet
partly natural, being found in some degree
even in the foetus, and is one of those marks
of Provident Wisdom of which every part of
our structure furnishes instances. The cutis
itself is still more striking for the strength and
density of its structure, which we observe
particularly in dissecting this part. The scal-
pel must be sharp indeed to cut through it
with ease. This, in fact, with its horny
cuticle is nature's provision against the injuries
to which the important parts of the sole are
exposed, and the only defence, the only sandal
worn to this day by multitudes. Its structure,
as shewn by removing carefully the cellular
tissue from its inner surface, is composed of a
number of whitish glistening fibres crossing
each other in every direction, and enclosing
in their meshes portions of that granular fat
which forms the layer immediately subjacent
to the skin. These meshes are closer and
smaller as we approach the outer surface,
where the cells entirely disappear. When the
cuticle is separated from it, the cutis exhibits
a vast number of exhalent pores, the source of
that profuse perspiration which is given off
from this part of the feet under exercise ; these
are pretty equally distributed over the sole, but
the great thickness of the epidermis at the
heel must impede the transpiration through it

* See an excellent paper by Mr. Key in Guy's
Hospital Reports. Vide Clinical Lecture on Corns
and Bunions, by Sir B. C. Brodie, Bart, in the
Med. Gazette, vol. xvii.

354

REGIONS OF THE FOOT.

to a considerable degree. The sensibility of
this part of the integuments is not at all in
relation to its apparent want of delicacy in
structure ; no part of the body possesses a
covering more acutely sensitive. The effects
of pricking, of titillation, of cold or heat
applied to the sole of the foot, exemplify this.
Its sympathies also are as remarkable for their
liveliness as for their extent. Not even the
arm-pits or sides of the ribs are at all equal to
it in this respect. The bladder, the urethra,
the stomach and intestines, in fact almost all the
mucous membranes, together with the whole
voluntary system of nerves, and through them
the whole system of voluntary muscles, may
be said especially to sympathize with and to
be influenced by this one part. Of this no
one can doubt when we see the effects of
sudden cold applied to it in relaxing spasm of
the urethra or bowels, in checking vomiting,
or in rousing the whole nervous and muscular
system during fainting, &c. The effect also of
hot applications of stimulants and irritants
applied to this part familiarly illustrate its ex-
tensive sympathies. The most sensitive part
of the sole is the hollow, that part where the
cuticle is least dense.

When the cutis is removed, we expose a
stratum of cellular tissue remarkable for its
density and toughness, and for the granular
fat with which its cells are rilled ; it lies imme-
diately under the true skin, and over the
plantar fascia. We may here observe that a
similar integument, and the same kind of cel-
lular web under it, is spread over the heel,
and, from the peculiarity of its texture, is
probably more likely to inflame under the
effects of pressure than the skin of other parts
of the body ; at any rate, it very frequently
does inflame, and even slough, when long
subjected to pressure ; and inattention to this
point is often the source of great misery in
the treatment of fractures and dislocations of
the lower extremity. The heel resting upon
some hard portion of the apparatus often so
torments the patient as to be a serious impedi-
ment to the successful treatment of the case.

The fascia plantaris demands our particular
attention. It is a strong tendinous structure
forming a covering to the muscles and impor-
tant structures of the sole. It is very thick
and dense at its posterior part, and becomes
thinner, though still of the same consistence,
at the anterior part. The cellular web just
mentioned strongly adheres to it externally,
while the muscles which it covers are not only
adherent to its inner side, but many of their
fibres arise directly from it. It not only forms
a layer of separation between these muscles
and the more external parts, but it sends pro-
cesses of a similar tendinous structure between
the principal muscles, which also afford origin
to many of their fibres. It divides itself into
three portions, one covering each of the three
principal groups of muscles found here. These
three portions are, however, united behind
where they arise in common from the under
projecting part of the os ealcis, while ante-
riorly the layer becomes quite incomplete from

the subdivision into five slips, each of these
again splitting to pass to be fixed into each
side of the heads of the metatarsal bones. The
situation, structure, and connexions of this
fascia, of the dense stratum of cellular tissue,
and of the peculiar skin covering this, are
highly important to the surgeon. The know-
ledge of these points teaches why phlegmonous
inflammation must be difficult of treatment,
and often dangerous in its results, whether it
occurs immediately under the skin or under
the fascia, but particularly in the latter situa-
tion, the dense unyielding structure of which
prevents the swelling from pressing outward,
thus greatly aggravating the pain and irritation,
and when matter has formed, equally prevents
its pointing outwards, and calls for the early
application of the lancet to give it free vent,
and thus prevent its spreading along the foot.
The structure of the parts just described is, as
far as it goes, an objection to the partial ampu-
tation of the foot recommended by Chopart,
wherein the flap is formed from these parts in
the sole, together with the muscles and tendons
found there. But this objection is by no
means fatal to operations upon these parts,
which have often been successfully performed,
and when they are so, often give a limb much
more useful than a wooden one.

We now come to the deep-seated parts of
the foot. These consist, 1. of the muscles
and tendons; 2. of veins and arteries; 3. of
nerves ; 4. of absorbents. The muscles and
tendons compose three principal groups des-
tined to accomplish the movements of the
great toe, of the three middle toes, and of the
little toe, and according to their destination
and use, so is their situation in the sole. On
the inner side the abductor, the adductor, the
flexor brevis, and tendon of the flexor longus
pollicis form a pretty considerable mass, and
have a separate slip of the fascia plantaris
lying under them, in contact with the most
superficial of them, viz. the abductor. On the
outer or fibular side of the sole, a similar mass
of muscles, but smaller, lie underneath the
metatarsal bone of the little toe, composed
also of an abductor and a short flexor, while
one slip both from the long and short common
flexors joins them anteriorly. The space be-
tween these two masses of muscles is occupied,
most superficially, and immediately in contact
with the plantar fascia, by the flexor brevis
digitorum, next by the tendons of the flexor
longus digitorum, accompanied by their acces-
sories ; posteriorly, the accessories or massa
carnea Jacobi Sylvii ; and anteriorly, the lum-
bricales, while deeper still than all there are
the interossei interni.

Amidst this number of small muscles, the
plantar arteries take their course in the follow-
ing manner. The posterior tibial artery, as
we have elsewhere seen (vide ANKLE-JOINT,
REGIONS OF), passing down behind the inner
malleolus, gets into the hollow of the os
ealcis, lying pretty close to this bone, and
covered only by the integuments, cellular
tissue, and fascia. It now passes between the
origins of the adductor pollicis, and in doing

REGIONS OF THE FOOT.

355

so divides into external and internal plantar.
The first of these, which is much the larger
of the two, runs in a somewhat semicircular
course, first forwards and outwards till it has
reached the base of the metatarsal bone of the
little toe, and then winds round across the
other metatarsal bones, till at that of the great
toe it terminates by uniting with the anterior
tibial. In this course it runs first between the
superficial and deep muscles, viz. first covered
by the abductor pollicis, then between the
flexor brevis digitorum and the long flexor
tendons ; it then becomes more superficial,
King between the flexor digitorum brevis and
the abductor minimi digiti ; then in crossing
back to the inner side of the foot, it runs deep
under all the muscles and tendons, except the
interossei. Thus this artery forms an arch,
called the plantar arch, having its convexity
forwards and outwards, its concavity inwards
and backwards. The branches which it sup-
plies in this course are, first, a number of large
muscular branches before it reaches the outer
side of the foot ; then from the convexity of
the arch itself, the digital arteries, one to each
metatarsal space, which, dividing at the first
joint of the toes, run one on each side of the
toe to its termination ; and lastly, those from
the upper and inner sides, being generally very
insignificant muscular branches and communi-
cating branches, these last going upwards
between the metatarsal bones to anastomose
with the metatarsal branches of the anterior
tibial artery. It is right, however, to state
that in this, as in every other part of the
arterial system, great variety is occasionally
found. The internal plantar artery is a com-
paratively small artery, merely going to supply
the muscles and integuments of the great toe,
and for this purpose passes forwards along the
under and inner side of the tarsus, covered by
the abductor pollicis as far as the first phalanx
of the great toe, where it divides into several
branches, supplying both sides of the great toe,
and the inner side of the second. The veins
which accompany the plantar arteries are, like
all deep-seated veins, two in number, one on
each side of the artery, and they terminate in
the hollow of the os calcis by forming the
posterior tibial veins. The plantar arteries are
accompanied also in their course by corre-
sponding nerves, the termination of the poste-
rior tibial nerve, which divides in the hollow
of the os calcis. The internal plantar nerve,
contrary to the order of the arteries, is the
larger of the two ; it runs in company with the
inner plantar artery, and sends branches to the
three inner toes, and to the inner side of the
fourth, while the external plantar nerve running
the course of the corresponding artery is dis-
tributed only to the fifth toe and outer side of
the fourth. The lymphatics of the sole of
the foot, like the rest of this system, are com-
posed of a superficial and a deep set, the
former collecting from all parts towards the
inner ankle; the latter accompanying the plan-
tar arteries and veins, and passing up also with
them behind the inner ankle, go with the tibial
veins to the ham. There are several synovial

bursae in this region which it is necessary here
to mention. They are surrounding the tendons
as they pass into the sole along the hollow of
the os calcis, viz. the flexor longus pollicis and
flexor longus digitorum. Their anatomical
description has been already given (see ANKLE,
REGION OF). Another synovial sheath is
surrounding the tendon of the peroneus longus
as it obliquely crosses the sole to its insertion.
This bursal cavity is situated close upon the
bone, and under the principal ligaments.

II. Plantar region of the toes. — Of the
toes we observe that the integuments of the
under part are always soft and pliable, com-
pared with the rest of the integument of the
sole, and possessing peculiarly the sense of
touch ; that under the skin at the extremity
of the toes there is a soft elastic cushion of
cellular tissue, analogous to that at the tip of
the fingers, and in this and in the cutis the
extremity of the digital arteries and nerves is
minutely ramified. The digital arteries them-
selves, with their accompanying nerves and
veins and absorbents, are running along the
edges of this under surface of the toes.
Lastly, the tendinous thecae, in which the
flexor tendons are lying, are situated along
the under surface of the phalanges of the
toes, and are particularly attached to the sharp
edges of these bones (see FOOT, JOINTS
OF). They have a smooth synovial lining
which prevents the effects of friction upon the
tendons, and facilitates their movements.

From the description which has now been
given of the organization of the plantar region
of the foot, we readily perceive, 1st, Why
deep wounds of this part are both followed by
considerable haemorrhage, and why this is at
the same time very difficult to stop. The
arterial branches are numerous and lie deep.
Before we can get at them either to press upon
or to tie them, we must do so through a thick
integument, a dense tendinous fascia, and
deep-seated layer of muscles. If we dilate
the opening in all these parts we wound many
more branches, while it is impossible at such a
depth, and through such part, to discover the
bleeding vessel, if the opening is small. We
are, therefore, compelled in such a case, if
pressure will not stop the haemorrhage, to tie the
posterior tibia! artery, either behind the ankle^
or at the lower third of the leg. But even this
is sometimes not sufficient to stop the haemor-
rhage, owing to the free anastomosis of the
arteria dorsalis pedis with the plantar arteries ;
and we are then compelled also to tie the
anterior tibial. 2d, We see why inflammation
and suppuration in these parts, whose parietes
as well as contents are in great measure ten-
dinous, are threatening both in their present
symptoms and in their consequences. Not
only is the ready detection of suppuration pre-
vented, but the efforts of nature to bring it to
the surface are resisted. The inflamed parts
are bound tight; if matter has formed, it is
obliged to burrow laterally, in contact with
nerves, arteries, tendons, &c. The inflamma-
tion spreading to the synovial sheaths either
impairs or destroys the movements of the
2 A 2

356

REGIONS OF THE FOOT.

tendons in them, or, going still further, com-
municates the inflammation to the tendon,
and occasions it to slough. Moreover, the
tendinous structure which envelopes some of
these bursal cavities is the cause of those
violent and alarming symptoms of constitu-
tional irritation, by no means uncommon when
only a very small quantity of matter has formed
within them, a state sometimes almost instan-
taneously relieved by a judicious opening made
with the lancet, and giving exit to even so small
a quantity of pus. 3d, Why severe contusions
or lacerations are here so often followed by bad
consequences, the power of repair in tendinous
structures, which so largely enter into the
composition of the parts about the foot, being
small, and consequently the inflammation fre-
quently proving the destruction either of the
structure or the functions of the parts affected.
The study of the nature and position of these
joints of the foot is of great interest and im-
portance to the surgeon, and it will not be in-
appropriate in this article to offer some obser-
vations upon some of the operations in which
they are concerned. Modern surgery, whose
greatest triumphs have been in the saving of
limbs, not in removing them, in discovering the
least possible quantity of loss by which the
disease might be eradicated, rather than the
readiest method of taking off the entire limb,
has taught us not to be deterred by the intrica-
cies of the numerous joints of the foot, but
fearlessly to lead the knife through any part of
them, so that we may only save a serviceable
portion, which may be more convenient than a
wooden substitute. The removal of the toes at
their joints is comparatively easy, though it
should be remembered, in amputating at the
metatarso-phalangeal joint, that this articulation
is situated much deeper than the corresponding
one of the hand, owing to the greater length of
the web and greater thickness of the member
itself. The metatarsal bones may be removed
separately or altogether from their junction with
the tarsus, as first done by Iley of Leeds, and
described in his Surgical Observations. The
removal of a single bone is, except it be either
the first or the fifth, more difficult and even
more dangerous, in regard to the liability to
after inflammation, than the removal of the
whole metatarsus. In performing this last
operation, the guide for entering the whole row
of joints is the projecting tubercle of the fifth
metatarsal bone, immediately behind which the
joint may be opened, and on coming to the
projection of the inner cuneiform bone, (see
Jig. 1 67,) most surgeons recommend the cutting

Fig. 167.

extracted, both with and without the attached
metatarsal bones. Of the former kind a very
remarkable instance is given by Mr. Key in the
second number of Guy's Hospital Reports, in
which the only bones of the tarsus left were the
os calcis, astragalus, scaphoid, and internal
cuneiform bones as a support to the great toe.
(See Jigs. 167 and 168, in the first of which the
dotted line represents the portion of the bones
of the foot which was removed in Jig. 168.)

Fig. 168.

off its projecting part, rather than to finish by
opening the joint. The tarsal bones have been

Should disease or accident have destroyed
all, or most of the bones in the front row of the
tarsus, they may all be readily removed by
amputation at the astragalo-scaphoid and calca-
neo-cuboid joints, an operation generally known
as that of Chopart, who first practised it. How
far, however, such a portion of the foot pre-
served is preferable to the use of a short wooden
leg applied to the end of the limb, amputated
a little above the ankle, (a plan which we have
used with perfect success,) certainly admits of
a doubt. At any rate its advantages cannot be
put in competition with the principle so admi-
rably illustrated by Mr. Key in the before
mentioned case, of saving, if possible, a portion
of the metatarsus and toes, though at the risk
of a more painful, and perhaps more dangerous
operation.

Upon a general survey of the structure and
form of the foot, we are struck with the differ-
ence between this organ in man and in all other
animals. The most striking peculiarities con-
sist in the great breadth of the foot, its short-
ness in proportion to the leg, the large size of
the bones of the tarsus, the relative shortness
and smallness of the four outer toes, and the
great size of the inner one, the great strength
of the calcaneum, and lastly, in those arches
produced by the arrangement and form of the
tarsal and metatarsal bones. The only animal
that nearly approaches to the form of man,
the monkey, yet differs from him in all these
points. Its foot is narrower and longer in
proportion to the leg, its tarsal bones are
smaller, its four outer toes are long like the
fingers, while the first is small, and separated
from the rest. The calcaneum is relatively
small, arid inclines upwards at its posterior
projection, while the peculiarities already spe-
cified necessarily occasion that the arches of
the foot are much less distinct than in man.
Indeed, in supporting itself erect, the monkey
rests very much on the outer side of the foot,
probably on this account. In all other animals
these differences are still more marked. What

MUSCLES OF THE FOOT.

357

now can be more evident or more beautiful
than the design manifested in this simple
arrangement of the foot! Man is physically
as well as morally intended to carry him-
self erect. The breadth of his base was ne-
cessary for his continued support ; the strength
of it is called for on account of the great
weight which erect progression throws upon
it. Its arches were essential not only to give
lodgment and defence to the vessels and nerves
of the plantar region, but, by the peculiarity
of their construction, to admit of a certain
degree of elastic yielding, which greatly dimi-
nishes the shocks from violent efforts in leaping,
running, &c. The shortness of the toes, aug-
mented by the depth of the webs, shows that pre-
hension forms no part of the design of the foot,
while the size of the first toe, and its connexion
with the others, points it out as the principal
instrument of progression, to which the rest
are auxiliary. The analogies between the foot
and the hand are striking; they have the same
general arrangement of bones and muscles,
and even the arteries and nerves, the joints
and ligaments, are in many respects similar,
but in the particulars just mentioned the dif-
ference is strikingly obvious and important,
and just in these respects it is that the feet of
the Quadrumana also differ from those of man,
showing a difference in their intended action,
the erect position, at the utmost being only
occasional, not being the natural habit, but the
foot being prepared and adapted for grasping
and clinging, for which the human foot is
quite unfit.

The construction of the arches of the foot
requires a few words. They are two in number,
a transverse and a longitudinal one. The latter
of these is principally found along the inner
edge of the foot, and as we pass towards the
outer side the longitudinal arch gradually
shortens and becomes more flattened, until at
the outer side the arch is entirely lost, the
bones of the tarsus and metatarsus resting
through their whole length upon the ground.
This is to a certain degree necessary from the
construction of the toes, these being weaker
and shorter, as well as their metatarsal bones,
as they are further from the great toe ; as their
strength therefore diminishes, the corresponding
part of the arch is shortened and flattened, and,
consequently, less strain is thrown upon them,
until, at the line of the little toe, the arch is
ob'itei-ated, and what weight is resting here
comes at once upon the ground. But from
this construction it follows that the longest and
the highest line of this arch falls upon the
strongest metatarsal bone and longest toe, and
that whatever yielding there is occurring in the
entire longitudinal arch is greatest in this part
of it. This is, indeed, proved by the fact that
the length of the foot in a sound state is in-
creased in the line of the great toe to the extent
of several lines, by resting the weight of the
body upon the foot, whereas it is not at all
increased in the line of the little toe. When,
therefore, the arch yields to the superincumbent
pressure, it does so chiefly along the inner side,
and the foot is thus, lo a certain degree, twisted.

the inner malleolus approached nearer to the
ground, while the outer is very little, if at all,
lowered. This explains to us the reason of the
scaphoid and inner cuneiform bones projecting
as they do in the flat foot, and of the pain ex-
perienced on the inner side of the foot in the
same deformity in all efforts to raise the heel in
walking. It may also in some degree account
for the fact of the more frequent occurrence of
dislocation of the tibia at the ankle-joint in-
wards than outwards, the arch of the foot
yielding first to the force of the accident on the
inner side, and thus tilting the whole ankle-
joint inwards. The utility in walking of the
'form and relation of the various parts of the
foot now mentioned is readily seen when we
unite the consideration of the structure of this
arch with the combined action of the gastro-
cnemii upon the heel, and of the peroneus
longus upon the outer side of the foot. The
united action of these muscles throws and
sustains the whole weight upon the strongest
and most elastic part.

Whatever has been said of the utility of the
longitudinal arch applies equally to the trans-
verse arch, which is supplementary and auxiliary
to the former in all its uses.

( A. T. S. Dodd.)

FOOT, MUSCLES OF THE.— In speaking
of the muscles of the foot we necessarily under-
stand not merely those muscles which are si-
tuated upon the foot, but those muscles pecu-
liarly belonging to it, which are concerned in
producing its motions wherever situated. The
muscles of the foot, in this sense, are partly
situated upon the leg and partly upon the foot,
and should, in a physiological view, be consi-
dered together, that we may the better under-
stand their separate and combined functions.
We shall therefore, in this, as in other ana-
tomical articles, first give the descriptive
anatomy of the muscles situated upon the foot,
and then examine their functions in connexion
with those others whose action is upon the
joints of the foot, and which are therefore
strictly muscles of the foot, but which are
anatomically described elsewhere. (See LEG,
MUSCLES OF THE.)

The proper muscles of the foot are, 1. those
on the dorsum ; 2. those on the sole.

The muscles on the dorsum pedis are the ex-
tensor brevis digitorum and the dorsal interossei.

1. The extensor brevis digitorum (Fr. pe-
dieiuc). — This is a short flat muscle, situated
upon the outer side of the tarsus and meta-
tarsus. It arises by fleshy and tendinous
fibres from the upper and anterior part of the
os calcis, in the hollow between that bone and
the astragalus (creux astragalo-calcanien), also
partly from the os cuboides. It immediately
forms a broad fleshy belly, the fibres of which
pass forwards and inwards, and divide into
four portions, from each of which proceeds a
slender tendon. These four tendons, of which
the two internal are the strongest, cross under
those of the long extensor of the toes, opposite
the heads of the metatarsal bones. Of the^e
tendons the internal is inserted into the base of

358

MUSCLES OF THE FOOT.

the first phalanx of the great toe, the others
are united to the outer edge of the long ten-
dons, with which they form the aponeurosis
which covers the dorsum of each toe. The
obliquity of this short muscle counteracts the
obliquity of the long extensor, ^nd it serves to
extend and to spread the toes, and to pull
them away from the great toe.

2. Interossei dorsales vel externi. — These are
four in number, and arise by double heads,
that is, they arise from both the contiguous
metatarsal bones, here occupying the whole of
the interosseal space, and thus concealing the
internal interossei, which are seen only in the
sole. Their flat tendon unites with that of the
long and short extensors, and is inserted into
the side of the bases of the first phalanges of
the toes in such a manner that, with internal
interossei, every toe has one of these little
muscles on each side of it, except the first toe,
which has two distinct muscles of its own for
the same action, and the little toe, which is
provided with a separate abductor. Their use
is to separate the toes, and perhaps to assist in
extending them.

In the sole of the foot the inner side is
occupied by the muscles of the great toe, con-
stituting what some French writers call the
thenar eminence. These muscles are as fol-
lows:—

1. Abductor pollicis pedis. — This commences,
by a tendinous and fleshy origin, from the tu-
bercle on the under and fore part of the os
calcis, from the ligament extending between
the os calcis and os naviculare, and from the
fascia plantaris. Its tendon unites with the
flexor brevis pollicis, and is inserted into the
internal sesamoid bone, and inner side of the
base of the first phalanx of the great toe. It
draws the great toe from the others.

2. Flexor brevis pollicis. — Lies between the
abductor and adductor, in contact with the me-
tatarsal bone. It arises, by two portions, from
the under and fore part of the os calcis, and
from the external cuneiform bone. It is united,
on each side, to the abductor and the adductor,
and is inserted with these, by a union of ten-
dons, into the two sesamoid bones and base of
the first phalanx of the great toe, having the
tendon of the long iiexor passing between the
two insertions.

3. Adductor pollicis. — This muscle, which is si-
tuated the most externally, or fibulad, of the mus-
cles of the great toe, commences by a tendinous
origin, from the calcaneo-cuboid ligament, and
from one or two of the metatarsal bones. It is
double at first, and then uniting, sends a tendon
to be fixed into the external sesamoid bone and
outer or fibular side of the base of the first pha-
lanx of the great toe, in close connexion with
the flexor brevis. It draws the toe towards the
others. The muscles of the little toe are situ-
ated on the outer edge of the foot, and form, in
that situation, a corresponding eminence, which
has been called the hypothenar eminence.

1. Abductor minimi digiti. — This arises from
the outer, under, and fore part of the os calcis,
and from the fascia plantaris. It forms a long
slender belly, and is fixed by its tendon into

the base of the first phalanx of the little toe,
and head of its metatarsal bone. It flexes and
abducts the little toe, and, by its attachment
to the metatarsal bone, it strengthens the arch
of the foot, which indeed may be said of almost
all the muscles of the foot.

2. flexor brevis minimi digiti commences
from the os cuboides and base of the metatarsal
bone of the little toe, and lying close to this
bone, it is inserted into the base of the first
phalanx. It is a very small muscle, and its
use is to flex the toe.

The middle of the plantar region is occupied
by six muscles common to all the smaller toes.

1. Flexor brevis digitorum, called also per-
Jbratus. — This muscle arises, fleshy, from the

anterior part of the protuberance of the os
calcis, also from the inner surface of the plantar
fascia, both from its central thick portion and
from the septa, which run between this muscle
and those of the great and little toes. Under
the metatarsus it sends off four small tendons,
which, entering the sheath on the under side
of the four outer toes, are inserted into their
second phalanx. Before these tendons arrive
at the point of insertion each of them splits, to
allow the passage of the tendon of the long
flexor, in a manner similar to what takes place
in the hand, and they thus have a double inser-
tion into the toe. The action of this muscle is
to flex the second joint of the four lesser toes.

2. Flexor digitorum accessorius, or massa
carnca Jacobi Sylvii. — This is a short muscle,
somewhat square in form, covered by the flexor
brevis digitorum. It arises, fleshy, from the
sinuosity of the os calcis, and tendinous from
the outer side of the same part; it is attached
anteriorly to the tendon of the flexor longus
digitorum, just before it divides. Its use is, evi-
dently, to assist the action of the long flexor.

3. Lumbricales. — These slender round mus-
cles are found between the tendons of the
long flexor of the toes ; they arise from these
tendons just after their division, and fix their
own tendon into the inner or tibial side of the
first phalanges of the four outer toes ; they act
by bending the first joint of these toes.

4. Interossei plantar es vel interni. — These
are three in number, smaller than the external,
and having their origin each from only one me-
tatarsal bone. Their insertion and action have
been mentioned when speaking of the external
interossei.

5. Transversulis pedis. — This little muscle
is situated across the heads of the metatarsal
bones, passing from the fibular side of the great
toe to the tibial side of the little one, and at-
tached to them all as it passes over them. It
goes under the tendons of the long flexors and
the lumbricales, or rather between them and
the bones. Its action is to draw the metatarsal
bones together, thus to consolidate, as it were,
and strengthen that an tero-posterior arch, which,
were its parallel portions allowed to spread out
unchecked, would be materially weakened, and
be less able to encounter the violent movements
to which the foot is liable in leaping, running,
&c.

We shall now enumerate the muscles which

MUSCLES OF THE FOOT.

359

are employed in the movements of the foot
and its several portions, and classify them ac-

The motions of the ankle-
joint are •

"1. Flexion accomplished^
bv 1

1. T
2. P
3 E

2 Extension performed
bv "*

4. E
rl. G
2. G
3. P

4. I
5 F

6. T
7. F
8. F
I I- 1

The motions between the
first and second row of«
tarsal bones* are .

The motions of the toes arex

'1. Downwards and in- I 2.
wards accomplished by . j 3.

f1'

2. Upwards and outwards J 2.

by Is.

I 4.

1.

2.
3.

1 . Flexion performed by .^ 4.
5.

6.
7.

2. Extension by

3. Abduction by

4. Adduction by

In this table we are struck with the propor-
tion which the antagonist muscles bear to each
other, both in numbers and in individual as
well as collective power. This proportion is of
course regulated by the demand for muscular
force in the ordinaiy movements of the joints.
The extension of the ankle, in the most ordi-
nary mode of its performance, implies the lift-
ing of the whole weight of the body by the
elevation of the heel, the toes resting upon the
ground. This, owing to the unequal length
of the two levers, requires an immense power,
while the shortness of the moveable lever allows
of very little extent of motion. The gastro-

* It is remarkable that so original and accurate
an observer as Dr. Barclay should attribute this
motion to the ankle-joint, and should deny any
motion, more than a mere yielding, to any of the
tarsal bones. But it is still more surprising that
he should make the same observation of the carpus,
when so very considerable a part of the ordinary
motion at the wrist is obviously between the two
rows of carj al bones. See Barclay on Muscular
Motion, pp. 404, 447.

cording to the joints upon which they act and
the movements they produce.

Tibialis anticus.
Peroneus tertius.
Extensor longus digitorum.
Extensor proprius pollicis.
Gastrocnemius externus.
Gastrocnemius internus.
Plantaris.

I lexor longus digitorum.
Flexor longus pollicis.
Tibialis posticus.
Peroneus longus.
Peroneus brevis.
Tibialis posticus.
Extensor proprius pollicis.
Flexor longus digitorum.
Flexor longus pollicis.
Peroneus Longus.
Peroneus brevis.
Peroneus tertius.
Extensor longus digitorum.
Flexor longus pollicis.
Flexor brevis pollicis.
Flexor longus digitorum.
Flexor brevis digitorum.
Flexor accessorius digitorum .
Lumbricales.

Flexor brevis minimi digiti.
Extensor proprius pollicis.
Extensor longus digitorum.
Extensor brevis digitorum.
Abductor pollicis.
Abductor minimi digiti.

f Prior indicis.
Interossei< Prior medii digiti.

L Prior tertii digiti.
Adductor pollicis.
Transversalis.

f Prior minimi digiti.
. 1 Posterior indicis.
Interossei1 Posterior medii digiti.

l^ Posterior tertii digiti.

cnemii are accordingly thick short muscles,
with a Ions: and powerful tendon. These are
assisted by the plantaris and five other muscles.
Flexion, on the contrary, which generally im-
plies merely the elevation of the foot, without
any other force to overcome, is adequately
provided for by only four muscles, and these
not large, indeed one of them very small.
The assistance rendered by the five auxiliary
muscles, which pass behind the malleoli,
though considerable on the whole, yet is small
individually in proportion to their size, owing
to the disadvantageous situation which their
tendons occupy at so very short a distance from
the centre of motion ; for this reason, — when
the tendo Achillis is ruptured, the patient is
as incapable of walking as if all the extensor
muscles were divided, yet when the body is
resting ihe antagonism of the extensors is not
entirely lost. The foot is not permanently bent
upwards, and the simple act of extension can
be accomplished without great difficulty. One
of the most remarkable of all the extensor
muscles, both as to its course and its function,

(1:

{:

i:

360

MUSCLES OF THE FOOT.

is the peroneous externus. (See LEG, MUS-
CLES OF.) The tendon of this muscle passes
behind the outer malleolus, then, running
downwards and forwards, it enters a groove
formed in the os calcis, close behind the pro-
minence of the base of the fifth metatarsal
bone. It then runs across the sole of the foot,
in contact with the bones, to be fixed to the
inner cuneiform bone and metatarsal bone of
the great .toe. The course and situation of the
tendon well deserve particular attention in the
dissection of the foot. Without some study, it
is impossible fully to understand its office, or
how essential its action is to the mechanism of
progression. If we examine the general form
of the foot, we see that the anterior end of it is
not square, owing to the comparative length of
the toes. These are not of equal length, but
are each shorter than the other as we proceed
outwards, the outermost of all being the short-
est. This part of the foot then is like the end of
an oblong, with one angle greatly rounded off.
When, therefore, the weight of the body is, by
the elevation of the heel, thrown forwards upon
the toes, there is necessarily a tendency, in this
shape of the foot, to tilt the pressing force out-
wards, whereas if all the toes had been of equal
length, the elevation of the heel would simply
have thrown the weight directly forwards, the
support being equal on both sides of the foot.
This tendency outwards, occasioned by the
difference in length of the toes, is still further
increased by the difference in strength, the
largest, the most unyielding support, being on
the inner side of the foot, the smallest and the
most yielding being on the outer. This then
being the construction of the basis of support,
some means of counteracting this tendency was
necessary to enable us to carry the body directly
forwards, even in the simple act of walking,
and still more in the more violent exertions.
This is accomplished by the peroneus longus,
whose tendon, like a girt, passes under the
outer edge of the sole, and thus, lifting this,
and in some degree turning the sole outwards,
throws the weight of the body upon the great
toe. This action of the muscle is particularly
exemplified in the movements of skaiting.

The movements of the bones of the tarsus
are so distinct and constant that we have clas-
sified the muscles which act upon them sepa-
rately from those of the ankle. (See FOOT,
JOINTS OF.)

The muscles of the great toe are remarkable,
as might be expected, for their size and strength.
The long flexor is considerably larger than that
common to the other toes, and gives to this a
slip of its tendon, so that the flexor longus pol-
licis does in fact assist in flexing all the toes.

The general arrangement of all the muscles
and tendons in the sole is very curious, and
has a further object than the mere flexion of the
toes. The great toe is, as we see, well provided,
and it needs this, since it bears the greatest
share of the burden of the body in walking,
&c. The muscular provision for the other toes
is as considerable, and indeed more so, in pro-
portion to the size of the toes. There is, 1st,
the llexor brevis digitorum; 2cl, the flexor longus

Fig. 169.

1 Flexor accessorius.

2 Flexor pollicis longus.

3 Flexor digitorum longus.

4 Slip from the flexor pollicis longus to the flexor

digitorum longus.

5 Lumbricales.

6 Tendon of long flexor.

digitorum ; 3d, this tendon receives an aux-
iliary tendon from the long flexor of the great
toe ; 4th, the massa carnea; 5th, the lumbricales.
There can be little doubt that the use of all
these muscles is to give a powerful support to
the antero-posterior arch of the foot, to which
purpose the mere ligaments would be little
equal. But we must admire not only the
number and force but the arrangement of these
muscles, which are so placed as to act, almost
all of them, from the same centre, and there-
fore with greater advantage for the object of
strengthening the arch. Thus the flexor brevis
digitorum lies pretty nearly central in this region,
while immediately under it the flexor longus
digitorum, running from within outwards, is
crossed in the opposite oblique direction by the
flexor longus pollicis, and these again are still
further checked outwards by the flexor accesso-
rius, so that the centre of action of all these mus-
cles and of the lumbricales also, which arise from
the long flexor tendon, is in the same line as the
flexor brevis, which lies over them, and as a
support to the great arch of the foot this arrange-
ment of the muscular chords must have a pecu-
liarly advantageous effect.

(A. T. S. Dodd.)

For the BIBLIOGRAPHY, see ANATOMY (INTRO-
DUCTION).

FORE-ARM.

361

FORE-ARM, (Surgical anatomy), (Anti-
brachium ; Fr. Avant-bras ; Germ, der V order-
arm). This term is applied to that portion
of the upper extremity which is situated be-
tween the elbow and wrist-joint.

In the well-formed male all the muscles of
this region, but especially the supinators, from
the fascia which covers them being extremely
thin, when thrown into action stand out in
strong relief, giving an appearance of great
power concentrated within a small space. In
the female, on the contrary, the fore-arm, from
the great preponderance of adipose tissue,
presents a swelling outline and rounded form,
not the less beautiful, perhaps, from indicating
deficiency of muscular energy, and conveying
the idea of softness and dependence.

The usual and least constrained position of
the fore-arm is with the hand between prona-
tion and supination, that is, with the palm
of the hand inwards and the dorsum outwards;
but for the purpose of anatomical description
the palm of the hand is supposed to face for-
wards and the dorsum backwards, the fore-arm
being extended. In this position the fore-
arm obviously differs from the arm in being
wider from side to side than from before back-
wards. Superiorly it presents in front a very
slightly convex surface, but inferiorly there is
formed by the flexor tendon a distinct central
projection, which is bounded by the flexor carpi
radiahs on the radial side, and by the flexor carpi
ulnaris on the ulnar.

The posterior surface of the fore-arm is more
irregularly convex than the anterior; the greatest
convexity is nearer the ulnar than the radial
edge, and is formed by the olecranon above
and the shaft of the ulna below, which is
covered only by the skin superiorly. A con-
siderable depression may be observed, bounded
on the inner side by the olecranon, and on
the outer by the supinators ; in this depression
the outer condyle may be felt. To the inner
side of the olecranon there is a corresponding
but much smaller depression, in which the
inner condyle is situated. For about three
inches above the wrist-joint the fore-arm pos-
teriorly is slightly concave in the centre in
consequence of the marked projection of the
ulna and radius on either side. In the motions
of pronation and supination the shape of the
fore-arm is considerably changed; but as no
practical advantage can attend a detailed ac-
count of the changes undergone, we shall not
dwell upon them here.

The parts composing the fore- arm are as fol-
low : the radius and ulna, the muscles of the hand
and fingers, the radial and ulnar arteries with
their branches, the venae satellites of these
arteries and the subcutaneous veins, the radial,
ulnar, median, and cutaneous nerves, the ab-
sorbent vessels, a quantity of cellular and
adipose tissue, various aponeuroses, and the
common : 'eguments.

The t.^guration, relative position, and
connection of the bones of the fore-arm have
been described in the article EXTREMITY.
They \. ve together in the flexion and exten-

sion of the fore-arm on the os humeri at the
elbow-joint, under the influence of the biceps
flexor cubiti and brachialis anticus, and the
triceps extensor cubiti and anconeus.

In the motions of supination and pronation
the radius is always rolled upon the ulna,
the latter remaining perfectly fixed, though
this fact has been disputed in consequence of
the thick sacciform ligament of the wrist and
the tendon of the extensor carpi ulnaris being
felt to roll under the finger when placed on
the inferior extremity of the ulna during the
motion of rotation and supination, and thus
communicating the sensation of a motiou in
the ulna itself.

The skin of the fore-arm differs considerably
on the dorsal and anterior aspects. On the
former it is coarse and comparatively rough,
containing numerous small hairs ; on the latter
it is smooth and more delicate, and the adipose
tissue being more abundant on the anterior,
the whole surface is more even, while on the
posterior the extensor muscles of the hand
and fingers, being slightly covered, project
considerably. Neither of the regions, however,
contain so much fat as most other parts of the
body.

The superficial veins which are subject to
the greatest variety, are usually more distinct
and numerous on the dorsal aspect, particularly
at the lower part.

The subcutaneous nerves, which are very
numerous, are derived from the following
sources : 1st, the internal cutaneous nerve,
which is one of the divisions of the axillary
plexus; 2dly, the cutaneous branch of the
radial ; 3dly, the musculo-cutaneous.

The internal cutaneous nerve divides into
two branches in the upper arm, in which
region it accompanies the basilic vein. These
two branches penetrate the fascia separately
above the elbow-joint, and the one, the an-
terior branch, descends on the front of the
fore-arm, the other, the posterior, on the back
of it. The anterior branch usually passes
behind the basilic vein, sending a small twig
or two anterior to it. Its course is continued
to the wrist-joint, supplying the skin on the
anterior and inner side throughout; the pos-
terior division accompanies the basilic vein,
and may be always traced to the back part
of the wrist.

The small branches of this nerve, which
cross in front of the basilic or median basilic
vein, are occasionally wounded in the opera-
tion of venesection ; an accident which gene-
rally excites considerable inflammation, with
severe constitutional irritation, symptoms which
are sometimes erroneously attributed to the
action of a foul lancet.

The skin on the anterior surface of the outer
half of the fore-arm is supplied with nerves
by the external cutaneous nerve, a division of
the axillary plexus : it is a deep-seated mus-
cular nerve in the upper arm and penetrates
the fascia, becoming subcutaneous anterior
and a little below the elbow-joint. In this
situation it is posterior to the median cephalic

363

FORE-ARM.

vein ; its branches are numerous throughout
its course, which terminates at the wrist-joint
in the supply of branches to the skin on the
dorsum and ball of the thumb, which inosculate
with the cutaneous of the radial.

This last-mentioned branch, the cutaneous of
the radial, is derived from its trunk on the
outer side of the middle of the arm ; imme-
diately after that nerve has emerged from
between the triceps extensor and the bone, a
series of branches is distributed to the skin
of the arm. The remainder of the nerve,
which is a descending branch of some size,
passes down behind the elbow-joint, and be-
coming subcutaneous supplies the skin of the
posterior surface of the outer half of the fore-
arm, and corresponds to the musculo-cutaneous
on the anterior. Thus it will be seen that
the skin on the inner side of the fore-arm,
both anteriorly and posteriorly, is supplied by
the internal cutaneous, while that on the outer
side is supplied in front by the musculo-cu-
taneous, and behind by the radial nerve.

The superficial veins of the fore-arm, though
subject to the greatest variety, are usually
distinguished by the names of the cephalic,
basilic, and median. The two first commence
on the back of the hand ; the cephalic on the
external, and the basilic on the internal side.
They freely anastomose at the lower part of
the fore-arm, after which they separate, and
reaching the anterior surface below the elbow,
are joined by the median vein, as described
in the article ELBOW.

The superficial absorbents take nearly the
same course as the veins, though they are
far more numerous, and on the whole pursue
a straighter direction. The course of these
vessels is occasionally demonstrated in the living
subject by active inflammation of their coats
following the absorption of irritating matter.

Aponeurosis. — The aponeurosis of the fore-
arm is simply a continuation of the same
structure, which surrounds and supports the
muscles of the upper arm ; it varies very much
in density and appearance in different situa-
tions ; this difference arises from the fact that
both the triceps extensor and biceps flexor
cubiti send to it many fibres, which not merely
give additional strength to its texture, but also
act as a medium through which these muscles
possess the power of making tense the fascia.
Phis provision for tightening and supporting
the fascia of the fore-arm is analogous to those
arrangements which we meet with in the thigh
and leg.

The fascia of the fore-arm is strongest at the
posterior part of the limb, on each side of the
olecranon. The fibres derived from the tendon
of the triceps on the external side pass trans-
versely outwards to be inserted into the outer
condyle, intermingling with the radial exten-
sors at their origin, at the same time firmly
connected to the olecranon process, posteriorand
internal edge of the ulna, thus forming a dense
and firm covering to the anconeus, between
which muscle and the extensor carpi ulnaris a
process of fascia is met with which forms a

dense septum between the two. The fibres
from the internal edge of the triceps at the
upper part also pass transversely, reaching the
inner condyle, intermingle with the origin of
the flexor muscles ; others again, descending at
the back part of the arm, form an aponeurosis
over the flexor carpi ulnaris; while those which
pass forwards intermingle with the aponeurotic
fibres of the biceps. These fibres from the
biceps are uniformly strong and distinct, and
give a great firmness and density to the fascia
on the inner side of the arm covering the flexor
muscles, which is not met with on the outer
side of the arm supporting the supinators.
The fascia in front of the fore-arm which covers
the supinators receives its last fibrous connexion
from the tendon of the deltoid. The fascia of
the fore-arm on reaching the posterior part of
the wrist-joint has interwoven with its texture
many beautifully distinct fibres, taking a
slightly oblique course from without to within,
and from above to below ; these fibres, which
are firmly attached to the radius on the outer
side and the ulna on the inner, become insen-
sibly lost in the fascia on the back part of the
hand, • which resembles in its homogeneous
appearance the fascia on the lower part of the
fore-arm; these supplementary fibres to the
fascia, though presenting a distinct edge neither
above nor below, act as a ligament to the exten-
sor tendons in their passage behind the wrist-
joint, which has been called by some anatomists
the posterior annular ligament ; between these
tendons and the ligament there is a large and
distinct bursa, not unfrequeritly the seat of
inflammation. The fascia on the lower and
fore part of the fore-arm, consisting principally
of transverse fibres, becomes gradually thinner,
and in front of the wrist-joint is inseparably in-
terwoven with the fibres of the annular ligament.
The aponeurosis of the fore-arm forms many
septa between the muscles. Commencing with
the description of the septa in the back part of
the arm, we find a dense and strong one sepa-
rating the anconeus from the extensor carpi
ulnaris, and from which the latter muscle takes
part of its origin. A second dips between the
extensor carpi ulnaris and extensor communis
digitorum, giving origin to both. A third is
found between the common extensors of the fin-
gers and radial extensors. The radial extensors
and supinators are not thus separated from each
other. A fourth process, distinct though com-
paratively thin, separates the supinator radii
longus from the brachialis anticus, the tendon
of the biceps, pronator radii teres, and flexor
carpi radialis. There is also another process
which unites the tendon of the supinator radii
longus on the outer side to the flexor carpi
ulnaris on the inner side, and forms a firm and
dense covering to the radial artery. The pro-
nator radii teres is scarcely separated from the
flexor carpi radialis by a distinct septum,
though the last-mentioned muscle is completely
separated from the palmaris longus by a dipping
in of the fascia. Between the flexor communis
digitorum sublimis and flexor carpi ulnaris
there is a very perfect and distinct septum.

FORE- ARM.

363

Of the different morbid growths which arise
in the cellular tissue of the fore-arm, those
which are superficial and those, which are
beneath the fascia require careful distinction,
the removal of the former being easily effected,
while all operations on the latter require great
consideration and care.

The superficial tumour projects under the
skin, creating some deformity ; it may be
moved with facility, for its attachments are
loose ; while, on the other hand, the deep-
seated or sub-fascial tumour has frequently a flat-
tened surface, and often appears, on superficial
examination, insignificant and of small extent,
while in fact its mass is considerable, bur-
rouing deeply between the muscles. It is to
be distinguished from the supra-fascial tumour
by its comparative immobility, by the various
effects produced upon it by the fascia when
in a state of tension or relaxation, by the pain
produced by pressure on nerves, or impediment
to the circulation from pressure on the vessels.
In the removal of the sub-fascial tumour the
operator must call to mind the direction and
relative position of the muscles in the neigh-
bourhood of it, as the roots or under surface
of these generally follow the interspace between
the muscles, and are thus guided to a great depth
among the vessels and nerves of the^fore-arm.

The same principles apply to the diagnosis
and treatment of superficial and deep-seated
abscesses. The superficial abscess is less cir-
cumscribed ; the matter is diffused without
limit through the subcutaneous tissue; from
its position the absorption of the superincum-
bent tissues takes place rapidly, the skin either
giving way entirely without the aid of the
surgeon, or else pointing at some particular
spot indicates where the abscess lancet may be
employed with advantage.

The sub-fascial abscess, on the contrary, pro-
ceeds slowly in many cases, and even insidiously,
bound down by the unyielding fascia ; it tells
us of its presence, in the first instance, rather
by the constitutional disturbance which it
rouses than any striking indications of local
mischief. These abscesses are occasionally the
consequence of inflammation commencing in
the theca of the flexor tendons, and the bur-
rowing of the matter upwards in the course of
the tendons. The septa of the fascia, which
have been described passing down between the
muscles to the bone, limit the passage of the
pus in different directions.

The fascia itself is not much subject to
disease, though it seems peculiarly disposed to
slough as a consequence of phlegmonous ery-
sipelas.

Vessels. — The main arteries of the fore-arm are
the radial and ulnar, into which the brachial
artery divides just below the bend of the elbow.
The brachial artery at this spot has on its outer
side the tendon of the biceps ; on its innpr
side, one of the venae comites, the median
nerve, and the pronator radii teres muscle.
Behind the brachial artery is the brachialis
anticus muscle, and in front of it the fascial
insertion of the biceps muscle.

The radial artery, which is the smaller of
the two divisions, pursues nearly the same
direction as the brachial, and in the lower part
of the upper third of the fore-arm is found
exactly midway between the radial and ulnar
surfaces, overlapped by the supinator radii
longus, and lying upon the tendon of the
pronator radii teres muscle, with the radial
nerve about a quarter of an inch to its outer
side, and separated by fat and cellular mem-
brane. From this point the radial artery
descends towards the wrist-joint, and at the
lower part of the upper half of the fore-arm
quits the pronator radii teres, and passes on to
the anterior surface of the flexor longus pollicis,
having the flexor carpi radialis to its inner side.
A little lower down, that is, at the upper part
of the lower third, the vessel emerges from
beneath the supinator radii longus muscle, and
is covered only by the fascia. In its further
course to the wrist-joint the flexor carpi radialis
maintains its position on the inner side, to
which the tendon of the supinator radii longus
corresponds on the outer. The radial nerve
no longer accompanies the vessel, for it has
now slid under the supinator radii longus, and
reached the posterior face of the arm. As the
radial artery just above the wrist-joint is
covered only by the fascia, and lies upon the
bone, its pulsations are easily felt, and in con-
sequence of its convenient situation is generally
selected by the medical practitioner to ascertain
the general state of the circulation. We should,
however, always bear in mind the great variety
both in size and distribution to which this
vessel is liable, and take the precaution of at
least examining the radial artery in both
arms.

The inner edge of the supinator radii muscle
is a certain guide to the situation of this artery
should the surgeon be required to secure it,
and this should always be effected by two
ligatures, as its free anastomosis below will
certainly produce secondary hemorrhage if this
precaution is neglected. As the nerve lies
on the outer side of the artery, the needle
must be passed from without inwards.

The ulnar artery has a deep course, first
passing beneath the median nerve, which se-
parates it from the pronator radii teres muscle,,
next beneath the flexor digitorum sublimis,
the two last muscles separating it from the
flexor carpi radialis and palmaris longus, and
upon the flexor digitorum profundus, and when
it reaches the tendon of this muscle midway
between the wrist and elbow-joints, it comes
into contact with the ulnar nerve, by which
it is separated from the flexor carpi ulnaris
muscle on its inner side. In its further descent
to the wrist-joint it is situated between the
flexor communis digitorum sublimis and flexor
carpi ulnaris. Gradually sliding behind, the
tendon of the latter remains covered by it
for about two inches above the annular liga-
ment of the wrist, in front of which it passes
into the palm of the hand. The third branch
worthy of mention in this division of the fore-
arm is the anterior interosseal. This vessel

364

FORE- ARM.

is a branch of the ulnar artery, and not unfre-
quently is of large size, though usually of a
calibre about intermediate to the two last men-
tioned. It arises from the ulnar artery where
that vessel is covered by the pronator radii
teres, and descending towards the interosseal
ligament reaches that structure a little below
the tendon of the biceps. It is accompanied
by a branch of the median nerve in its course
downwards ; lies between the interosseous liga-
ments and the external edge of the flexor com-
munis digitorum profundus ; it terminates by
dividing into two branches, of which one
passes backwards through the interosseal liga-
ment, anastomosing with the posterior inter-
osseal, and the other, a small branch , descends
over the wrist-joint into the palm of the hand,
where it anastomoses with the deep palmar arch.
In the posterior region of the fore-arm we
meet with only one vessel of any size ; this
is the posterior interosseal artery, a branch
from the anterior interosseal, which passes
through the interosseal ligament opposite the
tubercle of the radius; its course is not so
straight and uniform as the anterior, its distri-
buent branches are larger and more numerous,
and it may be said to ramble down between
the extensor muscles and the interosseal liga-
ment, though it does not lie so immediately in
contact with the ligament as the anterior inter-
osseal. It terminates by anastomosis with the
vessels about the wrist-joint.

Such is the usual distribution of these ves-
sels ; they are, nevertheless, subject to every
kind of variety, and the operator previously to the
commencement of an operation ought always
carefully to examine the course of these vessels
in order to detect any anormal arrangement
either in relation to their size or distribution.

The arteries of the fore-arm are more ex-
posed to accidents from cutting instruments
than most other vessels in the body ; and the
usual plan of securing the vessel in these cases
is to apply two ligatures on the wounded
trunk, one above and the other below the orifice,
the latter being required in consequence of the
free anastomosis of the vessels in the hand.

But the fore-arm is occasionally wounded by
sharp penetrating instruments, which passing
deeply into the fleshy mass, the vessel which
has been wounded is not immediately indicated,
and the surgeon is consequently at a loss to
discover which of the three main trunks requires
the application of a ligature.

An examination through the wound would
tend to aggravate the mischief, and besides,
the search is often attended with difficulty, and
often unsatisfactory.

In such cases it will be found far more
advantageous to arrest the hemorrhage by pres-
sure on the brachial artery, at the same time
allaying the local inflammation by due attention
to the position of the arm, and the usual
antiphlogistic remedies, a plan which I have
seen adopted with great success by Mr. Tyrrell,
at St. Thomas's Hospital.*

* Sec St. Thomas's Hospital Reports, edited by
John F. South, No. i. p. 25.

There are some cases, however, which im-
peratively require the application of ligatures,
as for instance, when either of these vessels is
opened by sloughing of the tissues from phleg-
monous inflammation, or from aneurism in the
fore-arm or hand. In the first of these cases,
patients have frequently been lost from the
temporary suspension of the hemorrhage by
the use of cold applications or accidental
circumstance, and its occurring again suddenly
during the absence of the surgeon.

In the performance of the operation of tying
the radial artery the supinator radii longus
muscle affords an unerring guide throughout
the fore-arm, but the surgeon must remember
that the inner edge of this muscle is not on the
outer side of the fore-arm, but as nearly in the
centre as possible. The needle must be passed
from without inwards, in order to avoid wound-
ing the nerve.

The ulnar artery cannot be secured in the
upper third of the arm, it lies so completely
covered by most of the flexors arising from the
inner condyle ; as soon as the vessel has gained
its position between the flexor carpi ulnaris
and the flexor digitorum communis, it may be
easily reached, the former muscle overlapping
it, and therefore forming an excellent guide.
The needle in this operation must be passed
from within outwards, as the nerve lies to the
ulnar side of the artery.

The bones of the fore-arm are not unfre-
quently fractured, either singly or together, but
the radius, from its external position and strong
connection with the bones of the hand, is more
frequently fractured than the ulna. The injury
generally takes place a little above the middle
of the bone.

When both bones are fractured, the accident
is frequently occasioned by the passage of a
heavy weight over the limb, the violence acting
immediately on the injured portions. In child-
hood these bones are sometimes bent instead of
being broken, and as the deformity is slight,
though the effect altogether very serious, the
nature of the accident is not very readily de-
tected.

" When these bones are fractured near their
inferior extremities," says M. Boyer,* " the in-
flammatory swelling might render the diagnosis
difficult, and cause the fracture to be mistaken
for a luxation of the hand. But the two cases
may be distinguished by simply moving the
hand ; by the motion, if there be luxation with-
out fracture, the styloid processes of the radius
and ulna will not change their situation ; but
if a fracture do exist, these processes will follow
the motion of the hand."

If the radius be fractured a little below the
head and above the tubercle, that is, through
the neck, and the annular ligament remain en-
tire, the deformity is so slight that there is great
difficulty in detecting the nature of the injury,
especially if there be much swelling and effu-

* Lectures of Boyer upon Diseases of the Bones,
arranged by M. Richerand. translated by M. Far-
rell, vol.i. p. 161.

MUSCLES OF THE FORE-ARM.

365

sion. Unless the surgeon can distinctly feel
the head of the radius, so that he can clearly
ascertain on rotating the lower portion with the
hand, that the upper does follow but remains
perfectly unmoved, he has ncsequivocal guide
as to the real nature of the injury.

If the ulna is fractured separately from the
radius, which seldom occurs, the injury gene-
rally happens to the lower third of the bone,
which is much smaller and more exposed than
the upper ; the accident is easily detected by
running the finger down the posterior edge of
the bone. When the radius is fractured near
its centre, the pronator quadratus muscle ob-
tains entire power over the bone, and drawing
the lower portion across towards the ulna,
causes a considerable projection in the anterior
interosseous space. If this be not corrected by
the use of a pad, as recommended a little fur-
ther on, the two bones will unite, and all mo-
tion of pronation and supination be entirely
lost.

In all these cases of fracture of the bones of
the fore-arm, nearly the same plan of treatment
is required, namely, 1st, two pads, increasing in
thickness from the elbow to the wrist, and not
wider in any place than the arm itself, suffi-
ciently soft to be pushed well into the interos-
seal spaces, applied anteriorly and posteriorly ;
a long linen roller enveloping the hand and the
whole of the fore-arm, and pressing the pads
between the two bones, so as to counteract the
action of the two pronator muscles which have
a tendency to bring them together. Splints ex-
tending from the elbow to the hand.

When the radius alone is fractured, it is ad-
visable not to support the hand, but to allow it
to hang down, and by this plan the hand acting
as a weight, will draw the lower fractured por-
tion, which has a tendency to overlap the
upper, downwards, and thus bring them into
apposition.

(Samuel Solly.)

FORE-ARM, MUSCLES OF THE.—

When we consider how varied and complex are
the motions of the arm and hand, it is no matter
of surprize that so many as nineteen muscles
should be found composing the fleshy mass of
the fore-arm.

These muscles may be classified in reference
to their action, and are briefly enumerated as
follows: —

In the first place there is one muscle physio-
logically belonging to the upper arm, the anco-
neus; the rest are connected with the hand;
for instance, there are three flexors of the hand;
flexor carpi radialis, flexor carpi ulnaris, pal-
mar is longus. Three extensors of the hand,
extensor carpi radialis longior, extensor carpi
radialis brevior, extensor carpi ulnaris. Three
long flexors of the thumb and fingers ; flexor
communis digitorum sublimis, flexor communis
digitorum prqf'undus, flexor longus proprius
pollicis. Five extensors of the thumb and
fingers, extensor ossis metacarpi pollicis, exten-
sor primi internodii, extensor secundi internodii,
extensor communis digitorum, extensor indicis.

Two supinators, supinator radii longus, supina-
tor radii brevis. Two pronators, pronator ra-
dii feres, pronator quadratus.

In proceeding to describe the attachments
and relations of the foregoing muscles, it will
be found convenient to examine them as they
are met with in the following regions of the
fore-arm. 1. The anterior region, which con-
tains a superficial and a deep set of muscles.
2. The posterior region, which likewise has its
superficial and its deep layers of muscles.
These regions again may be conveniently sub-
divided into radial and ulnar sections, between
which a very natural line of demarcation is
observable after the skin and adipose tissue
have been removed.

Exactly on this line, and one-thiid from the
elbow and two-thirds from the wrist-joint, two
long muscles will be found in contact, the supi-
nator radii longus in the radial section, the
flexor carpi radialis in the ulnar. Above and
below this point these muscles diverge. The
flexor carpi radialis, at its origin from the inter-
nal condyle, is distant, from the boundary line
referred to, at least one-third of the transverse
diameter of the arm, and the space thus left,
triangular in its figure, contains a large portion
of the pronator radii teres. The radial edge of
the pronator radii teres is in contact with the
supinator radii longus to the extent of about
an inch and a half; this muscle descending in
like manner obliquely from its origin in the
ulnar section towards the radial leaves above a
similar though small triangular space, in which
the tendon of the biceps flexor cubiti is lodged.
Below the point referred to above, between the
elbow and wrist, the flexor carpi radialis runs
in contact with and on the ulnar side of the
boundary line till within an inch and a half of
the wrist-joint, where it gradually slides into
the radial section, so that at the annular liga-
ment the tendon of the flexor carpi radialis
will be found entirely in the radial region with
its internal edge in contact with the boundary
line.

Thus it will be seen that a line drawn from
the elbow to the wrist and dividing the fore-
arm into two portions, of which the internal
or ulnar section is exactly two-thirds, while the
external or radial section is only one-third of
the transverse width, not merely forms an arti-
ficial division into radial and ulnar sections,
but also points out the exact situation of the
tendon of the biceps, the outer edge of the
pronator radii teres, and the flexor carpi radi-
alis, and in addition, as we shall presently see,
the supinator radii longus. The fleshy belly
of this muscle lies exactly parallel with this
boundary line in the upper half of the arm.

In consequence of the supinator radii longus
becoming tendinous about the middle of the
fore-arm, and the tendon being narrower in its
transverse diameter than the muscle, a space is
left at the lower part of the arm between it and
the flexor carpi radialis, and the supinator radii
longus is no longer met in contact with the
boundary line. In this space is lodged the
radial artery, lying midway between these two

366

MUSCLES OF THE FORE-ARM.

tendons, separated from the flexor longus pol-
licis by a deep layer of fascia, which is united
to the edge of the supinator radii longus on the
outer side, and the flexor carpi ulnaris on the
inner side

MUSCLES IN THE ANTERIOR REGION OF THE
FORE-ARM. — a. Superficial layer of muscles. —
On the radial side we observe two, supinator
radii longus and extensor carpi radialis lon-
gior.

1. Supinator radii longus, (grand supina-
teur, Cloq., brachio-radialis, Soemm.,) arises
by a broad, flat, fleshy origin from the rough
ridge, on the outer side of the lower extremity
of the os humeri, which gradually terminates in
the outer condyle; it is connected at the apex of
its origin with the deltoid : it arises likewise
from the intermuscular ligaments of the upper
arm ; passing over the elbow-joint, its surfaces,
which in the upper arm face outwards and in-
wards, are converted into anterior and posterior
in the fore-arm ; opposite the tubercle of the
radius it becomes tendinous on its under sur-
face, and the fleshy fibres on its anterior face
entirely disappear about, the middle of the fore-
arm in a flat tendon, which, narrowing as it
descends, is inserted into the external edge of
the base of the radius.

This muscle at its origin has to the inner
side of it the brachialis anticus muscle and the
radial nerve and superior profunda artery ; to
its outer side and posteriorly the triceps ex-
tensor cubiti ; a little lower down and just
above the elbow-joint it has the extensor carpi
radialis longior to its outer side, which maintains
a uniform relation to it in its whole course ; in
passing over the elbow-joint the tendon of the
biceps flexor cubiti separates it from the bra-
chialis anticus; below the tendon of the biceps
muscle, we meet with, first, the pronator radii
teres in apposition with its internal edge ; and,
next, the flexor carpi radialis. In contact with
its posterior face superiorly is the supinator
radii brevis ; below this muscle the tendon of
the pronator radii teres ; and still lower down
the flexor longus pollicis.

The supinator radii longus, in addition to its
action as a supinator of the hand, is a flexor
of the fore-arm upon the arm.

2. Extensor carpi radialis longior, (radi-
alis externus longior, Soe'mm., humero sus-me-
tacarpien, Chauss., Dumas,) arises from the
lower extremity of the ridge above referred to,
and from the 'outer condyle. Advancing for-
ward it passes over the front of the elbow-
joint, and soon becoming tendinous on its an-
terior surface descends on the anterior part of
the fore-arm, partly overlapped by the tendon
of the supinator radii longus — its tendon gra-
dually seeks the posterior part of the arm, and
running through a broad shallow depression
appropriated to it and the second radial exten-
sor, finishes its course by being inserted into the
back part of the metacarpal bone supporting
the index finger. This muscle, as its name
implies, is an extensor of the hand, possessing
also a slight power in effecting its abduction.

In the ulnar section of the anterior super-

ficial antibrachial region we find five mus-
cles.

1. Pronator radii teres arises tendinous,
above the elbow-joint from the intermuscular
ligament of the upper arm, from the front part
of the internal condyle of the os humeri, from,
the process of fascia separating it from the flexor
carpi radialis, and from the ulna close to the
insertion of the brachialis anticus. This muscle,
though tendinous at its origin, soon becomes
fleshy, and from its rounded form, which causes
a distinct projection beneath the skin at the front
and upper part of the fore-arm, derives its name.
Its fleshy fibres terminate in a tendon as it
enters the radial section, which gradually be-
comes wider as it descends, and sliding behind
the supinator radii longus and extensor carpi
radialis and in front of the radius, is inserted
into the outer and back part of that bone. The
pronator radii teres has to its outer side, supe-
riorly, the tendon of the biceps muscle; below the
tubercle of the radius it has the internal edge of
the supinator radii longus in apposition with
it, and as it slides in a spiral direction round
the radius, and behind this muscle, it has the
supinator radii brevis superior and external to
it ; to its inner side it has throughout its course
the flexor carpi radialis.

In the ulnar section the anterior surface of this
muscle is in contact with the fascia; in the
radial it is covered by the supinator radii
longus, the two radial extensors, and crossed
by the radial artery and nerve. The posterior
surface of this muscle is in contact with the
anterior ligament of the elbow-joint, the bra-
chialis anticus, the median nerve, ulnar artery,
the flexor communis digitorum sublimis and
radius. This muscle, while presenting a smooth
and tendinous face to the under surface of the
supinator longus and radial extensors, conti-
nues fleshy on its under surface to the very
point of its connexion with the radius, the
muscle beneath, whose surface is in contact
with its fleshy fibres, being clothed in a similar
manner with tendon; this admirable contri-
vance for preventing friction is by no means
peculiar to this situation, though its utility is
frequently overlooked.

The name of this muscle indicates its action
as a pronator of the hand, and when that
effect has been produced, if its contractile
power be still further excited, it will flex the
fore-arm upon the upper. In case of fracture
of the radius, this power is excited injuriously
in bringing the radius across the ulna, and thus
obliterating the interosseal space, and if not
corrected by the surgeon, causing unnatural
union of the two bones.

2. Flexor carpi radialis ( M. radialis internus,
Winslow, Albinus, Lieutaud, Sabatier, Soe'mm. ;
grand palmaire, or radial anterieur, Cloquet;)
arises from the internal condyle of the humerus
in common with the last-mentioned muscle; at
the point where these two muscles are con-
nected with the humerus there exists no na-
tural separation between them. About an inch
and a half from their origin a separation is
effected by the dipping in of the fascia forming

MUSCLES OF THE FORE-ARM.

367

one of the muscular septa previously referred to.
At the lower part of the upper third of the fore-
arm their separation is complete. The flexor
carpi radialis first changes its muscular fibres
for tendinous on its anterior face, and a rounded
tendon is the result at the upper part of the
lower third of the arm. This tendon passes in
front of the wrist-joint and through a groove in
the os trapezium, is ultimately inserted into the
base of the metacarpal bone supporting the
fore-finger.

This muscle has on its outer edge, in the
superior third of the fore-arm, the pronator
radii teres, in the two inferior thirds the supi-
nator radii longus; the palmaris longus to its
inner edge, both at its origin and throughout
its whole course in the fore-arm. Anterior to
it there is simply the fascia, its posterior face
is in contact with the superficial flexor of the
fingers above and the long flexor of the thumb
below. The tendon of this muscle projects
distinctly through the skin at the lower part of
the arm.

The flexor carpi radialis, besides flexing the
whole hand on the fore-arm, bends the second
row of carpal bones upon the first. It will also
act as an abductor of the hand, in consequence
of its being fixed on the outer side of the hand
in the pulley-like groove of the trapezium
through which it passes. It slightly assists the
pronator muscles in their influence over the hand.

3. The palmaris longus, Soe'mm., epitrochlo-
palmaire, Chauss. The origin of this muscle,
which is in common with the other flexors, is
from the inner condyle, also from a tendinous
intermuscular septum which separates it from
the flexor carpi radialis on the outer side and
the flexor communis digitorum on the inner.
This muscle, the smallest of those situated in
the fore-arm, becomes tendinous midway be-
tween the elbow and wrist-joint. This tendon,
which is narrow and slender, descends to the
annular ligament, and is ultimately connected
with the palmar fascia. This fascia has some-
times been considered as a mere expansion of
the tendon of the palmaris longus, but as the
muscle is occasionally wanting and the fascia
never, we regard it rather as another instance
of that useful connexion of muscles with fascia?
which we have already had occasion to admire.
This muscle, except at its origin where it has
the flexor carpi radialis to its inner side and the
flexor communis to the outer, maintains a posi-
tion completely superficial to the other muscles,
its posterior face lying upon the flexor communis
sublimis.

This muscle flexes the hand, and makes
tense the palmar fascia and annular ligament,
and thus takes off from the palmar vessels and
nerves and the tendons of the digital flexors the
pressure to which they are exposed when the
hand grasps a solid body firmly; as, for in-
stance, when the whole weight of the body is
sustained, as in the case of the sailor climbing
the rigging of a vessel, by the power of the
flexors of the fingers and hand.

4. Flexor communis digitorum sublimis per-
foratus. ( Musculus perforatus, Soe'mm., epi-

trochlo-phalanginien commun, Chauss.) This
muscle also arises from the inner condyle in
common with the other muscles, and from a
strong tendinous septum separating it from the
flexor carpi ulnaris. About the middle of the
fore-arm this portion of the muscle is joined by
muscular fibres which arise from the radius im-
mediately below the insertion of the supinator
radii brevis, and on the inner side of the pro-
nator radii teres. Between these two origins
of the flexor communis digitorum is placed the
median nerve. The tendinous fibres, into which
the muscle is gradually transformed, become
first apparent on the anterior surface, and next
being collected ultimately split into four cords,
which passing behind the annular ligament of
the wrist, enter the palm of the hand ; oppo-
site the first phalanx of the four fingers these
cords, splitting into two portions and allowing
the passage of the deep flexors, terminate by
being inserted in the rough edge on the sides
of the second phalanges. The tendons of this
muscle as well as the deep flexor are bound
down to the phalanges by smooth tendinous
sheaths or thecae which are dense and firm be-
tween the articulations, but insensibly disap-
pearing opposite the joint, where their presence
would interfere with the motion of the parts ;
they are lined by synovial membrane to prevent
unnecessary friction.

Although the lateral width of this muscle is
considerable, only a very narrow edge is in
contact with the fascia, the remainder being
covered by the last-mentioned muscles, so that
some anatomists have described it as constitu-
ting a middle layer.

On the internal edge is placed the flexor
carpi ulnaris, which maintains the same relative
position to it throughout the fore-arm. In
contact with its posterior face we have the
flexor digitorum profundus, the flexor longus
pollicis, and the ulnar artery, vein, and nerve.

This muscle flexes the second phalanx on
the first, and the first on the metacarpus, and
the whole hand on the fore-arm.

5. Flexor carpi ulnaris, (musculus ulnaris
internus, Soe'mm, cubital interne, Portal, cu-
bito-carpien, Chauss.) This muscle arises from
the internal extremity of the internal condyle
of the humerus from the tendinous intermuscu-
lar septum, between it and the flexor carpi digi-
torum sublimis, and from the olecranon process
of the ulna; between these two heads the ulnar
nerve is situated ; its origin from the ulna is
not limited to the olecranon process, for it con-
tinues its connexion with that bone nearly as
low down as the origin of the pronator quad-
ratus. This muscle, which arises tendinous
and fleshy, merges into tendinous fibres on its
anterior surface at the upper part of the lower
third of the fore-arm. The tendon by degrees
becomes more rounded, but does not cease to
receive fleshy fibres until it terminates by be-
coming inserted into the annular ligament and
os pisiforme.

The flexor carpi ulnaris, forming the inner
margin of the muscles of the fore-arm, is in
contact with the fascia : its external edge touches

368

MUSCLES OF THE FORE-ARM.

the flexor communis digitorum sublimis. The
relation of this muscle to the ulnar artery has
induced some anatomists to denominate it
muscle satellite de Varttre cubitale.

In addition to its power as a flexor of the
hand on the fore-arm, this muscle adducts the
hand, drawing it towards the mesial line.

b. The deep layer of muscles. — These are
three in number, the flexor longus proprius
pollicis, flexor communis digitorum profundus
perforans, and the pronator quadratus. A por-
tion of the supinator radii brevis is also found
in it.

1. The flexor longus proprius pollicis,
Sffimm. ( Radio -phalangettien du pouce,
Chauss.) This muscle, situated most exter-
nally, arises by two heads ; one, narrow, rounded,
tendinous, and fleshy, from the inner condyle
of the humerus; the other, broad and fleshy,
from the front of the radius, below the insertion
of the biceps and supinator radii brevis, and
from the interosseal ligament, extending as low
down as the insertion of the pronator quadratus.
Its tendon, first formed on its internal and
anterior edge, descends behind the annular
ligament of the wrist-joint, and taking its
course between the two heads of the flexor
brevis pollicis, is inserted into the last phalanx
of the thumb.

This muscle is covered anteriorly by the
supinator radii longus and extensor carpi radialis
longior, except at the lower part, where it is
simply covered by the deep fascia on which
the radial artery lies. To its inner side is the
flexor digitorum profundus.

This muscle is a flexor of the last phalanx
of the thumb, a powerful and important muscle
in grasping objects.

2. Flexor communis digitorum profundus
perforans. (M. perforans, Soemm. M. cubito-
phalangettien commun, Chauss.) arises tendi-
nous from the front of the ulna immediately
below the insertion of the brachialis anticus
into the tubercle of that bone, and from the
same as low down as the pronator quadratus ;
also from the interosseous ligament. It becomes
tendinous on its anterior face about the middle
of the fore-arm, thus presenting a smooth and
polished surface to the muscles in front of it :
like the superficial flexor, it forms its four
tendons, which, after traversing the palm of
the hand and piercing the split tendons of the
superficial flexor, are ultimately inserted into
the third phalanx of each of the fingers.

This muscle has the flexor longus pollicis
to its outer side ; the flexor carpi ulnaris to its
innei ; and the flexor carpi radialis, flexor com-
munis digitorum sublimis and palmaris longus,
anterior to it.

To flex the fingers on the hand, commencing
with the flexion of the last phalanx on the
others, and the whole hand on the fore-arm,
constitutes the principal action of this muscle.

3. Pronator quadratus, Scemm. (Cubito-
radial, Chauss.) This muscle, entirely covered
by those mentioned above, presents a beauti-
ful appearance on their removal, from the ten-
dinous surface admitting by its transparency

the colour of the muscle to shine, as it were,
through it.

It arises from the ulna about an inch and a
half above the wrist-joint, occupying exactly
that extent of the surface of the bone with its
attachments : it is inserted fleshy into the lower
part of the radius.

This muscle, simple as its action appears,
that of rolling the radius over the ulna, per-
forms a most important part in those easy mo-
tions of the hand which the artist uncon-
sciously produces when he is engaged sketching
in bold and flowing lines the subject of his
picture.

To the surgeon a knowledge of the attach-
ments of this muscle is peculiarly important,
for in those cases in which the radius is frac-
tured near its lower extremity it draws the
injured bone into the field of the flexor tendons,
and by bringing it into close contact with the
ulna, produces a deformity which great care
will alone obviate.

Posterior antibrachial region. — If we now
look to the posterior part of the fore-arm, we shall
find that though it may be divided into radial
and ulnar sections like the anterior, the propor-
tions between them will be very different ; for one-
fifth of the transverse diameter of the arm alone
can be correctly allotted to the radial region in
the upper part, and two-fifths close to the wrist-
joint. The line of demarcation between these
two regions is accurately formed in the dissected
arm by the radial edge of the extensor com-
munis digitorum. This muscle, like those on
the anterior surface of the arm, is wide and
muscular above, tendinous and comparatively
narrow below ; and hence we find the radial
section wider below than it is above. In the
ulnar section, we have the extensor communis
digitorum to the outer side ; in contact with
this muscle, on its ulnar side, is the extensor
carpi ulnaris. This muscle, at its origin at
the upper part of the arm, is narrow, and the
space, thus yielded as it were by its form, is
occupied by the anconeus, which forms the
boundary of this region on the ulnar side.
The space left at the lower part of the arm,
from the divergence of the tendons of the
extensor carpi ulnaris and extensor communis
digitorum, permits a view of the indicator.
The radial section contains at its upper part
solely the extensor carpi radialis brevior ; but
at the upper part of the middle of the arm, we
have sliding into it from behind the extensor
communis digitorum, the extensor ossis meta-
carpi pollicis, and extensor primi internodii
pollicis. These pursue their course obliquely
across the radial section till they reach the outer
edge of the arm. Lower down than these
muscles and scarcely in contact with their
inferior edges, we discover the tendon of the
extensor secundi internodii pollicis likewise
emerging from beneath the extensor communis
digitorum.

a. Superficial muscles of the posterior anti-
brachial region. — 1. Anconeus (epicondylo-
cubital, Chauss.) though usually described as
a distinct muscle, is, in reality, a continuation

MUSCLES OF THE FORE-ARM.

369

of the triceps extensor cubiti : the fibres of each
are perfectly continuous, and there is no line
of demarcation between them. An artificial
boundary may be made by drawing a line
horizontally inwards when the fore-arm is ex-
tended on the upper arm, between the outer
condyle of the os humeri and the olecranon
process of the ulna. With this view of the limit
of the upper edge of the anconeus, it may be
described as a triangular muscle, the base above
and the apex below. This muscle arises ten-
dinous from the back part of the outer condyle,
its external and anterior edge continuing ten-
dinous almost to its insertion; its superior
fleshy fibres pass transversely inwards and
backwards, to be inserted into the fascia of the
fore-arm and also into the olecranon ; the middle
and inferior fibres pass backwards to the ulna
with various degrees of obliquity, and occupy
by their insertion about one-third of the bone
from its superior extremity.

This muscle is a simple extensor of the
fore-arm.

2. Extensor carpi ulnaris, (ulnaris exter-
nus, So2mm. ; cubito sus-metacarpien, Chauss.)
arises from the back part of the outer con-
dyle between the anconeus and the extensor
communis digitorum, with which latter muscle
it is so intimately connected that, more strictly
speaking, it ought to be said to arise in a
common tendon. Connected by a narrow
origin to the humerus it gradually expands,
and about the middle of the fore-arm, a tendon
being formed in the centre, it exhibits in its
further course a well-marked specimen of the
double penniform muscle. The tendon of this
muscle, in its passage towards the wrist-joint,
runs in an especial groove appropriated for its
reception in the back part of the ulna ; it ter-
minates by being inserted in the metacarpal
bone supporting the little finger. The extensor
carpi ulnaris is more or less connected with the
fascia throughout the whole of the upper arm.

This muscle extends the first row of carpal
bones on the second and the whole hand on
the fore-arm ; it is likewise an adductor of the
hand.

3. JEj tensor communis digitorvm (epicondulo
sus-phalangettien commun, Chauss. Dumas)
arises from the back part of the outer condyle
in common with the extensor carpi ulnaris on
its outer side, and the extensor carpi radialis
brevior on its inner side. The connexion of
this muscle to the os humeri is extremely
narrow in comparison with the width of the
muscle in the centre of the fore-arm. In its
ample attachment to the fascia it resembles the
flexor ulnaris, and, like it, is a penniform
muscle. We not unfrequenly find a portion
of this muscle so entirely distinct from the
rest that anatomists have occasionally described
it as a separate muscle, under the name of the
extensor proprius minimi digiti ; for being
inserted into the little finger, it possesses the
power of extending that portion of the hand.
It passes behind the posterior annular ligament
of the wrist-joint, splits into four tendons,
which, expanding on the back part of the
phalanges of the four fingers, convey the power

VOL. II.

of the muscle to each phalanx in an equal
degree. The tendons of this muscle in their
passage behind the annular ligament of the
wrist-joint are clothed by a synovial membrane
(reflected like all other synovial membranes) so
as to form a perfect purse or bursa. Both
these muscles are intimately connected upon
their under surface at the upper part of the
arm, with the aponeurosis covering the supi-
nator radii brevis.

This muscle is an extensor of the fingers and
the hand on the fore-arm.

4. Extensor carpi radialis brevior, (radialis
extemus brevior, Scemm. Epicondylo sus-
metacarpien, Chauss. Dumas), with a small
portion of the extensor carpi radialis longior,
occupies the radial division of the poste-
rior superficial antibrachial region. This
muscle arises from the outer condyle by a
flattened narrow origin, in common with the
extensor communis digitorum, being overlapped
on its outer side by the extensor carpi radialis
longior. This muscle, like most we have
described in the fore-arm, swells out towards
the centre, where, gradually becoming tendi-
nous, it again diminishes in size. It passes the
same groove in the radius as the extensor carpi
radialis longior, and terminates by an insertion
into the metacarpal bone of the middle finger.
The under surface of this muscle is tendinous
at the upper part of the arm, which permits it
to play without friction upon the smooth and
tendinous face of the supinator radii brevis
with which it is in contact.

This muscle acts as an extensor of the hand
on the fore-arm and an abductor.

b. Deep muscles of the posterior antibrachial
region. — The muscles in this region com-
mencing above, are the supinator radii brevity
the extensor ossis metacarpi pollicis, the exten-
sor primi internodii pollicis, the extensor
setundi internodii, and the indicator.

1 . Supinator radii brevis, ( epicondylo-radial,
Chauss.) arises tendinous from that portion of
the outer and back part of the ulna, unoccupied
by the insertion of the anconeus ; it arises also
from the back part of the outer condyle, covered
at its origin from the outer condyle by the
extensor communis digitorum and by the exten-
sor carpi radialis brevior. Its posterior and
external surface is tendinous, its internal fleshy,
and it embraces so much of the upper extremity
of the radius, as to form an imperfect tube.
Anteriorly we find it partly overlapping the
tubercle of that bone, with the tendon of the
biceps which is inserted into it. Bet weerr' these
and the under surface of the muscle is a large
and distinct bursa mucosa ; it covers rather
more than the upper third of the radius by its
insertion, extending as low down as the pro-
nator radii teres.

This muscle is the main agent in effecting
the supination of the hand.

2. Extensor ossis metacarpi pollicis, (ab-
ductor longus pollicis manus, Soeram. cubito-
radi sus-metacarpien, Dumas,) arises from the
ulna, interosseous ligament, and the back part of
the radius, opposite the insertion of the pronator
radii teres, having to its outer side the supi-

2 B

370

FOURTH PAIR OF NERVES.

water radii brevis, to its inner the extensor primi
internodii pollicis. It is covered posteriorly by
the extensor communis digitorum and extensor
carpi ulnaris. Gliding downwards and out-
wards from beneath these muscles and becoming
tendinous on its under surface, it slips over the
lower third of the posterior face of the radius,
and then running in a groove on the outer side
of that bone, common to it and the next men-
tioned muscle, is ultimately inserted into the
metacarpal bone of the thumb.

The action of this muscle is to extend the
metacarpal bone of the thumb, which corre-
sponds as regards its capacity for motion, with
the phalanges of the fingers.

3. Extensor primi internodii (extensor
minor pollicis manus, Soemm.; cubito sus-
phalangettien du pouce, Chauss.) is a very small
muscle compared with the last, though varying
much in size in different subjects. It lies
between the extensor ossis metacarpi pollicis
and the extensor secundi internodii, passing
through the same groove in the radius as the
extensor ossis metacarpi pollicis, it becomes
inserted into the first phalanx of the thumb.

4. The extensor secundi internodii pollicis
(extensor major pollicis manus, Soemm. ; cubito
sus-phalangettien du pouce, Chauss.) — This
muscle is usually larger than the former ; it
arises fleshy from the ulna and interosseous
ligament ; becoming tendinous in its centre, it
presents the same penniform appearance referred
to above. The groove in the radius which is
narrow and deep, this tendon alone being
lodged in it. It is situated between that for
the two radial extensors and the broad and
hollow one for the common extensors and
indicator. Crossing on the back of the wrist
the radial extensors it is finally inserted into
the second phalanx of the thumb. This mus-
cle is entirely covered in the fore-arm by the
common extensors of the fingers.

5. The indicator (cubito sus-phalangettien
de I'index) occupies the remaining portion of
the posterior interosseal space. Like the three
last described muscles it is penniform, and
tirises fleshy from the ulna and interosseous
ligament, it descends to the hand and passes
through the same groove at the back of the
radius as that of the extensor communis digi-
torum, it is inserted into the posterior surface
of the three phalanges of the index finger.
This muscle is entirely concealed by the exten-
sor carpi ulnaris and extensor communis digi-
torum.

The names of this and the two preceding
muscles indicate their actions.

For BIBLIOGRAPHY, see ANATOMY, (INTRO-
DUCTION.)

(Samuel Solly.)

FOURTH PAIR OF NERVES (nervus
trochlearis, s. patheticus). — The fourth pair is
the most slender of the encephalic nerves. They
are intermediate in the order of succession to
the third or motor oculi and the fifth nerves, and
hence the name. Each nerve is attached at its
encephalic extremity to the lateral part of the

superior surface of the anterior medullary
velum or valve of Vieussens, immediately behind
the testes or the posterior of the tubercula
quadrigemina. It is divided at its attachment,
for the most part, into two roots, inserted at a
little distance from each other, one close to the
testes, the other posterior to it. Occasionally it
has but one root and sometimes even three.
Gall and Spurzheim* are of opinion that the
nerve might be traced to a more remote point,
and according to May of " its fibrils appear to
pass through the filaments of the pillar of the
valve, and in part to arise from the back part
of the medulla oblongata."

The nerve is concealed at its insertion by the
superior vermiform process of the cerebellum,
and it is not immediately provided with neu-
rilemma, and hence, as also because of its
delicacy, it is very easily broken off.

Its course within the cranium is circuitous
and long, longer than that of the other nerves.
It passes outward, downward, and forward :
it first descends external to the superior peduncle
of the cerebellum (the processus a cerebello ad
testes), between it and the vermiform process,
then becomes invested with arachnoid mem-
brane and free, and runs round the lateral part
of the crus cerebri, above the superior margin
of the pons Varolii, and beneath the free edge
of the tentorium cerebelli, until it reaches the
posterior clinoid process of the sphenoid bone ;
it then enters the outer wall of the cavernous
sinus between the points of attachment of the
tentorium, and is transmitted through a canal
in the dura mater, by which the wall is formed,
forward to the foramen lacerum of the orbit.
It does not enter the sinus, being contained in
a canal in its outer wall.

At the posterior part of the sinus the nerve
is situate beneath the third, between it and the
first division of the fifth nerve; but at the
anterior, and as they are about to pass into the
orbit, the fourth and frontal branch of the fifth
are both above the third, the fourth internal
and a little superior to the frontal.

The nerve lastly enters the orbit through the
superior part of the foramen lacerum in com-
pany with the frontal, above the levator palpebne
muscle, and immediately beneath the roof of
the region. Having entered, it runs forward
and inward, gains the surface of the superior
oblique muscle, and attaching itself to it upon
its superior aspect, about its middle, it divides
into filaments, which are all distributed to the
muscle.

The fourth nerve does not give off any branch
during its course to the oblique muscle, unless,
at times, first a filament described by Cruveilhier,
and, according to him,distributed to the tentorium
cerebelli. This filament arises from the nerve
while traversing the wall of the cavernous sinus,
runs backward into the substance of the ten-
torium, and divides into two or three branches:
Cruveilhier calls it " the branch of the tento-
rium." Secondly, according to both Swan and
Cruveilhier, the fourth nerve gives off a fila-

* Anatomic du Systeme nerveux.
t Physiology.

GANGLIONS

371

ment to the lachrymal branch of the fifth.
Before its entrance into the orbit the nerve
receives a filament from the sympathetic,* and
at or immediately after entering, it receives one
also from the frontal branch of the fifth, by the
accession of which it is sensibly increased in
size. It is very closely connected to the frontal
itself at the back of the orbit.

Upon the fourth nerve the power of the
superior oblique muscle is considered to depend.
It is remarkable that this muscle should be
provided with an especial nerve, differing,
apparently, so much in its encephalic relations
from those by which the others are supplied ;
but the theories which have been advanced
upon the subject are as yet so unsubstantial,
that we think it better to leave them untouched.
(See ORBIT, MUSCLES OF THE).

The nerve exists with similar relations in all
the vertebrata.

For the BIBLIOGRAPHY, see NERVE.

(B.Alcock.)

GANGLION, (Gr. yayyXto* ; Germ. Nerven
Knoten.) — This term is applied to several dis-
tinct structures : to the nodules placed on cer-
tain nerves, to the lymphatic glands or gan-
glions, to certain bodies, as the thyroid, the
thymus, 8cc., which have been called by some
anatomists vascular ganglions, and iastly, in
surgical language, to the enlargement of the
synovial bursae. It is, however, most gene-
rally applied to the ganglions of the nerves ;
but of late years many anatomists, who con-
ceive that the various masses of grey matter
met with in the encephalon and spinal chord
are, together with the ganglia of the nerves,
sources of nervous power, have extended to
those masses the general term of ganglion.
Although there can be no doubt that the
analogy has a real foundation, and that this
application of the word is both convtrcient and
correct, it is nevertheless proposed, in obe-
dience to custom, to retain the old and more
limited sense of the term ganglion, and to
devote tto present article to the structure of
the ganglions of the spinal and sympathetic
nerves, referring the reader for an account of
the functions of these bodies to the articles
NERVOUS SYSTEM and SYMPATHETIC NERVE.

The nervous ganglions consist of a number
of oval or roundish organs connected with
certain nerves, and placed deeply in the trunk
of the body, to whkh they are confined, being
situated, with the exception of those of the
head, in the immediate vicinity of the vertebral
column. Their number and size are subject to
variation, not only in different persons, but even
on the two sides of the same individual ; the
following is the enumeration which approaches
nearest to the truth : thirty on each side of
the body, placed on the posterior roots of the
spinal nerves ; one on each side, situated on
the larger origin of the fifth pair; the ganglions
of the great sympathetic consisting of the follow-
ing, connected on each side of the body with what

* See Pauli in MUller's Archiv. for 1834.

is regarded as the trunk of this nerve, vkt. thcee
cervical, twelve dorsal, three to four or five
lumbar, three to five sacral ; to these we must
add some large masses placed near the mesial
plane, viz. two semilunar, three or four coeliac
ganglions, and one cardiac ganglion, first de-
scribed by Wrisberg, but which is occasionally
deficient ; and lastly, forming a part of the great
sympathetic, the ophthalmic, the spheno-pala-
tine, the otic, and the submaxillary ganglions,
and a small body usually met with in the caver
nous sinus, the cavernous ganglion. M. Hip.
Cloquet has described in rather vague terms a
small reddish mass placed in the anterior
palatine canal, which he calls the naso-palatine
ganglion ; but Arnold, Cruveilhier, and others
deny, and with good reason, the existence of
this body. A gangliform enlargement is con-
stantly seen on the commencement of the ner-
vus vagus, and a second lower down ; a
similar swelling is also placed on the glosso-
pharyngeal nerve (g. petrosum).

Professor Miiller of Berlin has discovered
above this enlargement a true ganglion on the
the glosso-pharyngeal (ganglion jugulare nervi
glosso-pharyngei), occupying half or two-thirds
of the trunk of the nervt, and being precisely
to that nerve what the intervertebral ganglion
and the Gasserian are to the spinal nerves and
the fifth pair. My colleague Mr. Walker has
shown me this ganglion, which is placed in the
upper part of the foramen lacerum basis cranii
posterius, and corresponds to the above descrip-
tion.*

Arnold has further noticed that at the junc-
tion of the superior twig of the Vidian nerve,
or nervus innominatus, with the facial nerve,
there is a gangliform swelling.f

Mayer has discovered a minute posterior
root of the sublingual nerve, with a ganglion
on it, in some mammalia (ox, dog, pig), and
in one instance in man.

Thus the total number of ganglions in the
human body amounts to about one hundred
and twenty-seven, exclusive of the gangliform
enlargements on the pneurno-gastric, glosso-
pharyngeal, and the facial nerves.

These bodies have been variously arranged
by writers on this subject ; thus by WeberJ
they are divided into ganglions of reinforce-
ment, such as those on the spinal nerves, and
into ganglions of origin, of which those of the
sympathetic, the ophthalmic, and the spheno-
palatineare examples; whilst Wutzer,§ classing
them according to their situation and relations,
considers that there are three orders, 1. the
cerebral ; 2. the spinal ; 3. the vegetative :
the first comprises the Gasserian ganglion, the
ophthalmic, and the ganglion of Meckel, to
which must be added the otic ganglion of Ar-

* This very interesting discovery confirms the
opinion that the glosso-pharyngeal is, like the spi-
nal and the fifth, a compound nerve of motion and
sensation. See Medizinische Vereins-Zeitnng.
Berlin, 1833.

t Icones Nerv. Corp. p. 2. tab. ii. and vii.

J Anat. Compar. nervi sympath.

$ De corp. hum. ganglior. fabrica atquc usu,
p. 52.

372

GANGLION.

nold ; in the second order are enumerated the
thirty spinal ganglions and the ganglionic en-
largement of the nervus va^us and glosso-pha-
ryngeus ; in the third division are included the
ganglions of the sympathetic nerve.

The former of these arrangements is objec-
tionable, because offices are assigned to the
ganglions the existence of which has not been
ascertained ; and the latter is so far erroneous
that in this classification the ganglion of the
fifth pair is separated from the spinal, to which
it is undoubtedly similar; whilst the ophthalmic
and spheno-palatine are as incorrectly divided
from the system of the sympathetic.*

In endeavouring to detect that which con-
stitutes the essential difference among these
numerous bodies, we ought to pay special
attention to the character of the nerves which
are attached to the ganglions. Taking this as
the only rational guide, I should refer them to
two classes. 1. Those which are placed on
sentient nerves, comprising the Gasserian, the
ganglion of the glosso-pharyngeus, and the
spinal ganglions The gangliform enlargement
of the nervus vagus should be referred to this
order, inasmuch as there can be little doubt,
although this at present is not proved, that this
nerve is compounded, like the spinal nerves, of
motor and sentient fibrils, a surmise supported
by the distribution of the vagus, and still more
by the interesting discovery of my friend
Mr. Solly, of the existence of certain motor
fibrils in the exact part of the medulla oblon-
gata, whence this nerve arises.f

2. Those which have connected with them
both motor and sentient nerves, and are, as I
believe, always in relation with contractile and
sensitive structures :J those, namely, of the
great sympathetic nerve, comprising the cer-
vical, the dorsal, lumbar, and sacral, together
with the cardiac, the semilunar and coeliac,
also the ophthalmic, the spheno-palatine, the
otic, submaxillary, and cavernous.

These classes nearly correspond with the

* The following is the classification of Mailer :
1. Ganglia of the posterior roots of the spinal
nerves, of the larger portioa of the nexvus trige-
minus, of the nervus vagus, and ganglion jugulare
nervi glosso-pharyngei. 2. Ganglia of the great
sympathetic. 3. Ganglia which occur at the points
of junction of the cerebro-spinal nerves with the
branches of the sympathetic, comprising ganglion
petrosum nervi glosso-pharyngei, intumescentia
gangliformis nervi facialis, ganglion spheno-pala-
tinum, ciliare, oticum (probably). To which should
h.e added ganglion submaxillare. Handbuch der
Physiol. der Menschen. Erster Hand. p. 588.

t According to the present opinion, the whole of
the fibres belonging to the nervus vagus enter into
the ganglion j and Bischoff imagines that this nerve
derives its motor portion from the spinal accessory.
The intimate relations between these two nerves
require further investigation.

$ It cannot be too often repeated that sensibility,
or, to speak more correctly, the capability of being
excited by the contact of a physical agent, may
exist without being accompanied wiih conscious-
ness : the inner surface of the heart, of the blood-
vessels, and intestine are as capable of being ex-
cited as the skin or the retina ; but the impressions
which they receive are not usually perceived by the
mind*

simple and compound ganglions of Scarpa* and
Meckel.f

There are occasionally found ganglia on
other nerves ; thus, Mr. Swan J has noticed one
on the posterior spinal nerve, where it is
placed under the extensor tendons of the
wrist. My friend Mr. Pilcher has also found
in two subjects a gangliform enlargement on
the internal nasal nerve, where it is lodged on
the aethmoidal bone.

It is necessary to remark that although the
ganglia of the first class are placed on certain
of those nerves which are commonly regarded
as being subordinate simply to sensation, yet
the highly important observations of Dr. M.
Hall,§ which have, I conceive, opened an en-
tirely new field in physiology, render it doubt-
ful that those bodies are essential to the exer-
cise of sensation.

Organization. — Although the cerebro-spinal
and sympathetic ganglia present some impor-
tant peculiarities when contrasted with each
other, particularly as regards the proportions
of the grey and fibrous substances, still as
both classes possess essentially the same struc-
ture, they may with propriety be considered in
a collective manner.

Every ganglion contains two totally distinct
substances which have a close relation to, and
are, I believe, identical with the grey and
fibrous matters, constituting the encephalon
and other parts of the nervous system. It is
true that the appearance of these bodies is in
many respects dissimilar to that of the brain ;
but at length it is universally admitted that
differences in mere physical properties are
unimportant, and do not constitute any test as
to the essential structure of an organ. In the
present instance the diversity may very readily
be understood when the difference of situation
is considered. The cerebral organ is enclosed
in a cavity, the cranium, formed of some of
the strongest bones of the skeleton, and hence,
being effectually defended from the effects of
motion and external pressure, all its parts are
soft and delicate; whilst the ganglia, placed
on bones which move on each other, slightly it
is true, are exposed to external compression,
and consequently a much firmer texture is
required. It is for this reason that these
bodies are invested in a dense fibrous capsule,
which is to them what the cranium is to the
encephalon, and which famishes in addition a
number of internal processes surrounding each
fibril, and sustaining the spherical masses
of grey matter. The difficulty of detecting
the intimate texture is by these means greatly
increased ; but as it is so similar to that of the
cerebrum, it is desirable to examine the con-
stituent parts according to the order observed
in investigating that organ.

I. Reddish grey matter. — The quantity of
this substance, often called the peculiar matter
of the ganglions, but which, as I have stated,

* Anat. Annotat. liber primus. De nerv. gang,
et plex. p. 9.

t Man. d'Anat. t. i. p. 231.

J On the Nerves, pi. xxii. fig. 3.

§ Lcct. on the Ncrv. Sys. 1836.

GANGLION.

373

is possessed by those bodies in common with
the brain and spinal chord, is very considerable,
constituting apparently the largest, and cer-
tainly the most essential part of the ganglion.
It is so intimately connected with the fibres
that these latter appear as if they were incrusted,
being surrounded in every direction by this
greyish matter; but although this intimate
intermixture is very evident, no fibrils can be
perceived actually terminating in or arising
from the grey matter. A section of one of the
sympathetic ganglia, the first cervical for ex-
ample, displays this incrustation of the fibres
and the interposition between them of rounded
masses of the grey matter ; but the Gasserian
is in many respects the most favourable for ex-
amination.

Much difference of opinion exists concerning
the true nature of this substance. Scarpa con-
tends that it is not analogous with the grey matter
of the brain, but that it consists of a rlocculent

tissue loaded with a mucilaginous fluid, which
becomes oily in obesity, and watery and abun-
dant in anasarca. The accumulation of fat in
the true gangl ionic tissue has, however, been
denied by Beclard, Wutzer, and others. Ac-
cording to Bichat, whose opinions must always
command our respect, " the ganglions have* a
colour very different from that of the nerves.
They present a soft spongy tissue, somewhat
similar to the lymphatic glands, but which has
nothing in common either with the cerebral
substance or with that of the nerves." It is
staled by Lobslein, who has published one of
the latest and most minute accounts of the
structure and diseases of the sympathetic
nerve,* that he has observed lying contiguous
to the white and filamentous tissue another
substance presenting a flocculent appearance,
with globules interspersed (materies vel sub-
stantia orbicularis tomentosa), and which he
regards as the second material of the ganglia.

Fig. 170.

Semilunar ganglion, twice the rtatural sixe.

a, a, Fasciculi of splanchnic nerve,
e, b, Fibres running through the ganglion.
cf c, Branches collected from the former,
emerging.

and

This juicy or gelatinous substance, which is
met with in the spinal as well as in the sympa-
thetic ganglia, does not, however, according
to Lobstein, appear to be an essential part of
the organization, as it varies in its proportion
in different ganglia, and may even be absent ;
nor, it is said, can it be assimilated with the
grey matter of the brain.

Ehrenberg also controverts the opinion that
the ganglia resemble the grey part of the brain ;
but although he has found by microscopical
inspection, that these bodies contain an over-

d, d, Flocculent or orbicular substance placed be-

tween and applied to fibres.

e, e, Foramina perforating the ganglion.

whelming proportion of large varicose tubes,
similar to those of the fibrous portion of the
brain, yet he has also shewn that they possess
minute varicose fibres like those of the grey
substance ; and what particularly is deserving
of notice, he has detected in the muscles of
the fibres granules similar to those which are
found in the cervical portion of

* De Nervi Sympath. Humani, fabrica, usu, et
morbis, p. 66.

t Structur des Seelenorgans bei Menschen und
Thieren, Berlin, 1836, p. 31.

374

GANGLION.

Notwithstanding these and other high au-
thorities, the researches of many recent writers,
which have thrown so much new and valuable
light on the mutual relations of the component
parts of the nervous system, leave little room
for doubting the identity of these two sub-
stances. The analogy of the whole nervous
system tends to prove that this peculiar matter
is nothing else than the grey substance ; in the
Gasseriari ganglion, indeed, the resemblance is
so striking that no doubt of their identity can
be entertained. This view of the subject was
taken by Winslow, Johnstone, and others ;
and lately the existence of grey matter has
been admitted by Dr. Fletcher, an assumption,
indeed, which is the basis of his hypothesis,
that the ganglionic system of nerves is the im-
mediate seat of irritability.*

II. Fibres. — This is a most important branch
of the present inquiry, because a knowledge
of the connexions of these bodies with the other
parts of the nervous system and with each
other, as well as of the internal disposition of
their fibres, is indispensable to the investigation
of their functions. The subject may be re-
solved into two questions, a. What is the
arrangement of the fibres in the ganglia ?
b. What is the nature of the fibres which are
connected with the ganglia ?

a. The internal disposition of the nervous
filaments, owing to the very intimate relations
subsisting between them and the grey matter,
is difficult to determine; and hence it has
happened that great difference of opinion pre-
vails on this point. I shall in the first place
describe the arrangement in the most simple
of these organs, and for that purpose shall
select that of the portio major of the fifth pair.
On inspection it is seen that the large coarse
fibrils of the nerve on approaching the ganglion
begin to spread out from each other, and although
in its interior they are, as we have already
observed, encrusted by the grey matter, yet,
on scraping this away, the fibres may be seen
still passing on uninterruptedly, but becoming
more and more separated from each other.
It is this disposition which Scarpa has aptly
enough compared to a rope the two ends of
which remain twisted, whilst in the middle
the component threads are unfolded and pulled
asunder. A similar, but less distinct arrange-
ment exists in the spinal ganglia.

Although the continuity of the fibres through
the ganglion is easily demonstrated, yet it
would be wrong to conclude that this passage
is all that happens ; for in the first place the
three branches of the trigeminal nerve which
emerge from, are decidedly larger than the
trunk of the same nerve which passes into
the ganglion. Their physical qualities are also
altered, especially as relates to their colour,
which, instead of having the whitish aspect
common to the proper fibres of the cerebro-
spinal axis, is for some distance of the reddish
hue proper to the ganglionic system ; and
again it would be in opposition to all our
notions of the properties of the grey matter

* Rudiments of Physiol. st. ii. a. p. 87.

to imagine that the fibres do not maintain
intimate connexions with that substance, by
which means its influence, whatever it may be,
is communicated to those threads.

In the sympathetic ganglions the internal
formation is much more intricate ; and it is
especially in reference to these bodies that so
much diversity of opinion prevails among
anatomists. The researches of Monro,* Scarpa,f
and Lobstein, J as well as ocular inspection,
prove that gome fibres undoubtedly pass without
interruption through the ganglion.

On making a section of the first cervical
ganglion, previously hardened by alcohol,
fibres will be perceived, which, although se-
parated from each other by irregular interstices
filled with grey matter, are still continued
uninterruptedly from one to the other ex-
tremity. There are, however, besides these,
other fibres, which are so complex that it is
almost impossible to demonstrate their exact
disposition. I believe, however, that, inde-
pendently of those fibrils which run through
the ganglion, there are some which terminate
in, and others which arise from the grey matter
in its interior.

Fig. 171.

Superior cervical ganglion of the great intercostal
nerve of the right side.

a, Trunk of the great intercostal nerve a little
below the foramen caroticum. b, Trunk of the
nerve below the superior cervical ganglion.
c, c, c, c, The branches which from the three
superior cervico-spinal nerves run to join the su-
perior cervical ganglion of the great intercostal
nerve, d, d, d, Nerves issuing from the superior
cervical ganglion, e, Nervous fibriform stratum of
the ganglion, f, Reticulated plexus produced by
the mingling of the nervous fibres, g, Reticulated
or plexiform nervous filaments. h, Nervous
filaments variously mingled with others connected
with the neighbouring cerebral and spinal nerves.
i, The nervous filaments of which the trunk of
the intercostal nerve below the superior cervical
ganglion is composed.

* Obs. on Nerv. Sys. p. 54.

t L. c. p. 14, Tab. 1. fig. 1, 2,3, 4.

± L. c. Tab. tcrtia.

GANGLION.

375

b. What is the nature of the fibres which
are connected with the ganglia? The very
interesting inquiries of Brown, Danvall, Teale,
Stanley, and others into the nature of those
frequent affections now generally known under
the term of neuralgic diseases, by which a
new and unexpected light lias been thrown
on a most obscure branch of pathology,
render this part of the present investigation
of pre-eminent importance. The mutual in-
fluence exerted by the cerebro-spinal axis
and the great sympathetic on each other,
in consequence of which disease of the brain
and spinal chord may cause morbid actions
and conditions of the organs of digestion,
circulation, and secretion, and vice versa, can
only be experienced by a reference to the
relations which exist between these two great
divisions of the nervous system. Unfortu-
nately, however, this question, so important
both as regards physiology and pathology, is
not easily resolved on account of the difficulty
in the present state of our knowledge of dis-
tinguishing from each other the different species
of fibres which enter into these organs. I
shall in the first place speak of the fibres
which are perceptible to the naked eye, and
afterwards point out the information that has
been afforded by microscopical examination.

The intervertebral ganglia (and these ob-
servations may be applied to those of the
fifth pair, of the glosso-pharyngeal, and of
.the pneumo-gastric) receive fibres only from
the posterior roots of the spinal nerves, "which,
since the researches of Bell, Magendie, and
Mayo, have been regarded as being subordinate
to sensation. But if the important principles
announced by Dr. M. Hall be susceptible, as
I believe they are, of that confirmation from
anatomical examination of which at present
.they stand in need, then to the true sensiferous
fibrils which enter these ganglia we must add
what are called by Dr. Hall incident filaments.
It is also a question which yet remains to
be decided, whether the twigs that are known
to run between the posterior roots of the spinal
nerves and the sympathetic ganglions pass in
reality from the former to the latter or from
the latter to the former; if, as appears most
probable, these threads are furnished by the
sympathetic, then it is to be presumed they
are subsequently continued to the intervertebral
ganglions.

With respect to the sympathetic ganglions,
the following are the only facts that are at this
time established,

1. There are longitudinal commissural fila-
ments by which the ganglia are joined to each
other, and by which they are formed, however
remote they may be from one another, into
one great and extensive system.

2. There are fibrils which extend between
the motiferous part of the cerebro-spinal axis
and the sympathetic, but whether they are
derived from the former or the latter is not de-
cided.

3. There are sentient fibrils observing a
similar disposition.

As the anatomical facts by which these facts

are established will be found under the head
SYMPATHETIC NERVE, only a few remarks are
required in this place.

1. With respect to the longitudinal com-
missural fibres, they are as necessary here as
in other parts of the nervous system ; and
although Bichat speaks of this connexion of
the ganglions being occasionally absent, such
deficiencies are extremely rare, and if they
do really exist, must be regarded as an ab-
normal state. The importance of this con-
nexion is rendered apparent by the union of
the several nodules placed on the trunk of the
sympathetic, which is so constant that anato-
mists were for a long time so far misled by
it as to compare this gangliated cord with the
common nerves of the body ; but it is perhaps
still more striking in the commissural fibres,
which are so invariably noticed passing from
the sympathetic to the small ganglia of the
head.

2 and 3. In consequence of the motor and
sentient nerves of the head usually forming
distinct trunks, the ophthalmic ganglion offers
a natural analysis, as it were, of the connexion
between the great sympathetic and the cerebro-
spinal axis. One twig passes between this
small body and the nasal nerve of the fifth pair
(sentient); a second extends between it and
the lower division of the third pair (motor).
The dissections of Arnold prove that a similar
connexion exists in the spheno-palatine, the
otic, and the submaxillary ganglia.* Mayo
has also ascertained that the branches placed
between the ganglia of the great sympathetic
and the compound nerves of the spine are
of a twofold character, one set being attached
to the sentient and the other to the motor root.
The adjoining figure (fig. 172), copied from a
dissection I made for this purpose, shows the
mode of communication in the thorax.

Fig. 172.

a, Anterior root. c, Ditto. b, Posterior root
entering the ganglion, d, Sympathetic ganglion.

e, Filament of communication to posterior root.

f, Filament of communication to anterior root.

* These connexions are very beautifully repre-
sented in his work, Icones Nerv. Capit. Tab. 5, 6,
7, and 8. On some points relative to the otic
ganglion it has been proved by the dissections of
Schlemm that Arnold was in error, especially as
relates to the branch supposed to be furnished from
the ganglion to the tarsor tympani.

37(5

GANGLION.

Notwithstanding «o many important points
have been established, it must be confessed
that much remains to be decided. Thus, for
example, we perceive that the ganglion of
Meckel, like the ganglions of the sympathetic
in the neck, has connected with it a motor
fibril ; but this fibril, as Arnold has observed,
presents the whitish character and firm texture
common to the cerebro-spinal nerves, and
therefore, it must be presumed, passes from
the portio dura to the ganglion, whilst the
twigs uniting the cervical nerves and tine
sympathetic are reddish and soft, rendering
it probable, as Fletcher supposes, that they
are furnished by the ganglia.

Such being the imperfect results of ocular
inspection, we are naturally anxious to obtain
more exact information, especially in reference
to the character of the different orders of fibres
which are connected with the ganglia. The
microscopical observations which are being car-
ried on at this time with so much zeal in Ger-
many, and from the prosecution of which the
most valuable evidence may be anticipated
respecting the undecided points of minute
anatomy, have already thrown some light on this
interesting question. Thus Ehrenberg* has de-
tected in the sympathetic not only the varicose
fibres which some imagine are proper to that
system, but also some of the cylindrical fibres of
which the cerebro-spinal nerves are principally
composed. According to Lauth and Remark,
the nerves of organic life (i. e. of the sympa-
thetic) consist for the most part of varicose
fibres mixed up with a small proportion of
cylindrical ; whilst those of animal life consist
principally of cylindrical mingled with a few
varicose fibres. This is the exact appearance
which must have been anticipated, if the mu-
tual interchange of fibres described by Bichat,f
W. Philip,! Mayo,§ Fletcher,|| and others,
really exist.

It may here be remarked that although the
accuracy of Ehrenberg's researches, confirmed
as they have been by Miiller, Purkinje, Valen-
tin and others, is called in question by Krause,
Berres, and Treviranus, yet the essential fact
of there being a decided difference in the phy-
sical character of different orders of nervous
fibres, and, consequently, a test for their suc-
cessful analysis, is universally admitted.^

Lastly, it is a question of great interest whether
there are not, independently of the relations
which exist between the sympathetic and the
cerebro-spinal axis, fibres proper to the former,

* L. c. p. 31.

t An. Gen. i. p. 220. " The ganglions (of the
sympathetic) like the brain furnish and receive their
particular nerves."

J On Vital Functions, and Gulstonian Lect.

$ Out. of Phy. 4th edit. p. 259.

|| Rud. of Phy. part ii. a. p. 76.

<|I Since the above was written I have leamt that
the doubts expressed by Treviranus, Arnold, and
others, as to the correctness of the views of Ehren-
berg, have been confirmed. Professor Miiller
attributes the appearance of the varicose fibres to
artificial causes ; and it is said that Ehrenberg
himself doubts if such fibres exist in the normal
condition.

which establish between them and the organs
they supply with nerves most important con-
nexions. Our present knowledge does not
afford the means of solving this question ; and,
although my attention has been particularly
directed to this subject, still, as my observa-
tions are as yet incomplete, I shall satisfy
myself by expressing my conviction that such
a system of nervous fibres does exist.

Covering. — Every ganglion possesses two
coverings : the outer one in the spinal ganglions
is very firm, being derived from the vertebral
dura mater, whilst in the sympathetic gan-
glions it is composed of condensed cellular
tissue. On raising very carefully the external
capsule, a more delicate tunic is exposed,
which adheres to the proper ganglionic tissue.

Bloodvessels. — These bodies, like all other
parts of the nervous system, are amply sup-
plied with arterial blood. After a successful
injection, two, three, or more arteries, derived
from the neighbouring vessels, may be readily
observed running to the ganglion. Each vessel,
having perforated the coverings of the ganglion,
forms according to Wutzer a plexus on the inner
surface of the capsule, and at length sends de-
licate branches into the pulpy matter, which,
with the aid of the microscope, may be ob-
served to run in the same direction with the
nervous filaments. The exact mode in which
these vessels terminate is unknown, but it is
probable, as in the cerebro-spinal system, that
each nervous fibre is accompanied by a mi-
nute artery and vein. No lymphatics have
been demonstrated, but analogy tends to prove
their existence, and Lobstein states that he
has often seen them forming networks around
the ganglions.

Chemical composition. — The experiments
performed by Bichat* and Wutzerf would tend
to show that the substance of the ganglions is
distinct in its qualities from the cerebral matter
and also from that of the nerves. By boiling, it
is at first hardened, but soon becomes softened ;
maceration in cold water renders it more soft
and pulpy, and if sufficiently prolonged, the
water being frequently changed, it is converted
into adipocire. It is liquefied by the alkalies,
and is rendered crisp and hard by the acids
and alcohol.

BIBLIOGRAPHY. — Haase, De gangliis nervor.
Scarpa, Anat. Annot. Liber i. de nerv. gang, et
plexibus. Monro, Obs. on nerv. system. Soem-
mering, De corp. hum. fabric, t. iv. Bichat, Anat.
gen. Wutzer, De corp. hum. ganglior. fabrica
atque usu. This work contains an elaborate list
of the various authors who have treated of the
ganglions, and an epitome of their opinions.
Lobstein, De nervi sympath. humani, fabrica, usu
et morbis. F. Arnold, Kopfthiel des Vegetativen
nervensystem, beim Menschen. J, Muller, Hand-
buch der Physiol. des Menschen, 1834. C. J. Eh-
renberg, Structur des Seelenorgans bei Menschen
und Thieren, Berlin, 1836 ; Anat. der Microsko-
pischen Gebilde der Menschlichen Kbrpers. Wien.

(R. D. Grainger.)

* Anat. Gen. t. i. p. 226.

t De Corp. Hum. Gang. Fabrica atque Usu,
$55. The reader will find in this work many* de-
tails relative to the above subject.

GASTEROPODA.

377

GASTEROPODA, (yeurnp, venter, wov<;,
pes; Eng. Gasteropotk; Fr. Gasteropodes ;
Germ. Bauc/i/'itsser ; Mollu&ca Repent ia,
Poli.)

Definition. — An extensive class of the Mol-
luscous division of the animal kingdom dis-
tinguished by the structure and position of their
locomotive apparatus, which consists of a mus-
cular disc attached to the ventral surface of the
body, serving either as an instrument by means
of which the animal can crawl, or in rarer
instances compressed into a muscular mem-
brane useful in swimming.

Characters of the class. — Body soft, enclosed
in a muscular covering, which, from its contrac-
tility in every direction, produces great variety
in the external form of the animal : the back is
covered with a mantle of greater or less extent,
which in most of the genera secretes a shell
either enclosed within its substance, or, as is
more frequently the case, external and suffi-
ciently large to conceal and protect the whole
body, in which case it is often provided with
an operculum capable of closing its orifice
when the animal is lodged within it. The head
is anterior, distinct, and generally furnished
with two, four, or six tentacles, which are
placed above the oral aperture, and merely
serve as instruments of touch. The eyes are
two in number, and are placed sometimes on
the head itself, but more generally at the base,
at the side or at the extremity of the tentacles ;
they are always very small, and not unfre-
quently wanting. The muscular disc which is
subservient to locomotion is called the foot,
and is generally broad and fleshy, formmg a
powerful sucker, bnt in some instances it takes
the shape of a deep furrow, or is compressed
into a vertical lamella. The respiratory appa-
ratus varies in structure ; in some genera it is
composed of vascular ramifications which line
a cavity into which the respired medium is
freely admitted. Others are provided with
branchiae, adapted to the respiration of water,
variously disposed upon the exterior of the
body, or concealed internally. The heart
generally consists of an auricle and ventricle,
and is systemic, or, in other words, receives
the blood from the organs of respiration, and
propels it through the body. The sezual
organs vary in their structure in different
orders ; in the greater number each individual
is possessed both of an ovigerous and impreg-
nating apparatus, but copulation is essential to
fecundity : in many the sexes are distinct,
and some are hermaphrodite and self-impreg-
nating. Some species are terrestrial and others
aquatic.

In separating the Gasteropoda into orders, the
naturalist finds in the position and structure
of the branchial apparatus a character suffi-
ciently obvious ; and as the arrangement of
these organs is modified by the circumstances
of each individual, and is generally in relation
with the peculiarities met with in the internal
organization of the animal, the branchiae are at
present universally referred to as affording a
convenient basis of classification. We shall
in this article follow the arrangement adopted

VOL. II.

by Ferussac, of which, as well as of the
systems of other zoologists, an outline is con-
tained in the following table.

Order I. NUDIBRANCHIATA + (Cuy.)

Syn. Polybranchiatafi and genus Doris,
Blainville ; Gasteropodes Dermobranches,l Du-
meril ; Gasteropodes Tritoniens, Lamarck.

In these the branchiae are symmetrical, as-
suming a variety of forms, but always placed
upon some part of the back, where they are
unprotected by any covering ; the animals may
be provided with a shell or naked, but they
are all hermaphrodite with mutual copulation,
and marine.

1st Sub-order, Anthobranchiata,§ Goldfuss;
Cyclobranchiata,\\ Blainville.

1st Fam. Doris.
2d Sub-order, Polybranchiata, Blainville.

2d Fam. Tritonia, Jig. 173.

3d Fam. Glaucus,fg. 174.

Fig. 173.

Fig. 174.

Order II. INFEROBRANCHIATA,

(Cuv. and Blain.)

Syn. Gust. DermobrancheSj Dumeril; Gast.
Phyllidiens, Lamarck.

In the Inferobranchiate Gasteropoda the
branchiae are arranged under the inferior border
of the mantle on both sides of the body, or
upon one side only : the mantle sometimes
contains a calcareous lamella. All the genera

* Nudus, naked-, branchiae, gills.
t IIoXu? , many ; branchiae.
$ Asp/ua, shin.
§ Avflsf, a flower.
|| KuxXo?, a circle.

2 c

378

GASTEROPODA.

are hermaphrodite with reciprocal impregnation,

and marine.

1st Sub-order, Phyllidiada, Cuv.

1st Fam. Phyllidia, Jig. 175.
2d Sub-order, Semi-phylUdiad*, Lam.

2d Fam. Gastroplax, Blainville.

3d Fam. Pleurobranchus, Cuv.

Fig. 175.

Order III. TECTIBRANCHIATA*

(Cuv.)

Syn. Chismobranches, Blainville ; Gust.
Adelobr cinches, -\ Dumeril; Gast. Phyllidiens
and Laplysieris, Lamarck.

In this order the branchiae are placed upon
the dorsal aspect of the body, but are pro-
tected by a fold of the mantle which almost
always contains a shell presenting a rudimen-
tary spire. They are all hermaphrodite like
the preceding, and marine.

1st Fam. Dikera.

2d Fam. Akera.

Order IV. PULMONALIA INOPER-
CULATA, (Ferussac)

Syn. Pulmones, Cuv.;J Pulmobranches,
Blainville; Gast. Trachelipodes,§ Lamarck.

The respiratory apparatus is here adapted to
the respiration of atmospheric air, and instead
of being composed of branchial tufts or la-
minae, consists of a cavity lined by the rami-
fications of the pulmonary vessels, the entrance
to which can be opened or closed at the plea-
sure of the animal. Almost all the species
are provided with a shell either turbinated or
concealed within the mantle, but are never
furnished with a calcareous operculum. Every

* Tectus, covered.

t A&r,Xof, concealed.

$ Pulmo, lunqs.

$ Tpa^»X«f, the neck ; irw<;, foot.

individual is hermaphrodite, but mutual copu-
lation is essential to fertility. Some are terres-
trial, others inhabit fresh water, and some are
marine.
1st Sub-order, Geophilida,* Ferussac.

1st Fam. Limax.

2d Fam. Helix.
2d Sub-order, Gehydrophilidarf Ferussac.

3d Fam. Auricula.
3d Sub-order, Hygrophilid<E,\ Ferussac.

4th Fam. Limn&us.

Order V. PULMONALIA OPERCU-
LATA, (Ferussac.)

Syn. Pectinibranchiata,^ Cuv. ; Siphoni-
branchiata,\\ Blain.

The respiratory organs of the animals form-
ing this order are similar in structure to those
found in the last, but they differ materially in
other points. In all the operculated division
the shell is closed by a calcareous operculum
not found in the last, and instead of that
hermaphrodite condition of the sexual organs
common to the inoperculated order, the sexes
are distinct, the male and female parts existing
in different individuals. They are all terres-
trial.

1st Fam. Helicina.

2d Fam. Turbicina.

Order VI. PECTIN1BRANCHIATA,

(Cuv.)

Syn. Trachelipodes, Lamarck ; Monopleuri-
branches, Blain. ; Gast. Adelobranches and
Siphonibranches, Dumeril.

This extensive order, which comprises most
of the univalve mollusks whose shells enrich
our cabinets, is characterized by a respira-
tory apparatus adapted to an aquatic medium.
The branchiae are pectinated, consisting of
ranges of fringes disposed like the teeth of a
comb, and generally enclosed in a dorsal cavity
which opens externally at the side of the body
or above the head. The shell is always turbi-
nated, and sometimes provided with an oper-
culum. The sexes are separate, and the ani-
mals fluviatile or marine.
1st Sub-order, Pomastomid&ft Ferussac ; Chis-
mobranches, Blainville.

1st Fam. Turbo, Lin.

2d Fain. Trochus, Lin.
2d Sub-order, Hemipomastomid<z, Ferussac.

3d Fam. Cerithium, Adanson.

4th Fam. Buccinum, Lin.

5th Fam. Murex, Lin.

6th Fam. Strombus, Lin.

7th Fam. Conus, Lin.
3d Sub-order, Apomastomid<z, Ferussac.

8th Fam.

9th Fam. Valuta, Lin.

10th Fam.
4th Sub-order, Addodermidte, Ferussac.

llth Fain. Sigarelus, Adanson.

* r»j, the earth ; <$>i*i<a, to love.

t IX the earth ; vtioop, the water ; <{nXs<».

t Typ«f, moist ; <$I\EOO.

§ Pecten, -inis, a comb.

|| 2»<f>ajy, a canal.

^ Uupa., operculum; <rro/ota, mouth.

GASTEROPODA.

379

Order VII. SCUTIKRANCHIATA*

(Cuv.)

Syn* Cervicobranches, Blain. ; Ckisjno-
branches, Blain. ; Gast. Dermobranches, Dum.;
G. Trachelipodes, Lam.

Fig. 176.

In this order the structure of the branchiae
is analogous to what has been described in the
Pectinibranchiata ; but the shell, which in the
latter was always turbinated, in the Scutibran-
chiata is a mere shield, in which the indications
of a spire are very slight or totally deficient.
There is never an operculum. The organs of
both sexes are united in every individual, but
there is no necessity for copulation, each ani-
mal being self-impregnating. The species are
all aquatic.
1st Sub-order, Anthopliora.\

1st Fam. Haliotis, jig. 176.
2d Sub-order, CalyptracidtP,\ Lam.

* Scutum, a shield.
t Avfloj, a flower ; $1?*
a covering.

to carry.

2d Fam. Capulus*
3d Sub-order, Heteropoda\ Nucleobranches,

Blainville.
3d Fam. Pterotrachea, Jig. 177.

Order VIII. CYCLOBRANCHIATA,

(Cur.)

Syn. Dermobranches, Dum. ; Gast . Phylli-
diens, Lam. ; Gast. Chismobranches, Blain.

In this order the branchiae are arranged
under the margin of the mantle around the
circumference of the body ; the shell is a
simple shield, either composed of one piece,
which is never turbinated, or else made up of
several divisions. They are all hermaphrodite
and self-impregnating.

1st Sub-order, Chismobranchiata, Blain.; Cy-
clobranchiata, Goldfuss.

1st Fam. Patella.
2d Sub-order, Polyplaxiphora,\ Blain.

2d Fara. Oscabrion.

Cuvier detaches the genera Vermetus, Magi-
lus, and Siliquaria from the Pectinibranchiata
on account of the irregular form of their shell,
which is only spiral at its commencement, and
is usually firmly attached to some foreign body,
a circumstance which involves as a necessary
consequence the hermaphrodite type of the
sexual organs, so that these genera are self-
impregnating. He has, therefore, arranged
them in a separate order, to which he applies
the name of Tubulibranchiata.

Tegumentary system. — The skin which in-
vests the Gasteropoda varies exceedingly in
texture, not only in different species but in dif-
ferent parts of the same animal ; its structure
being modified by a variety of circumstances
connected with the habits of the creature, the
presence or absence of a calcareous covering, or
the mode of respiration. In the naked Gaste-
ropods, especially in the terrestrial species, it is
thick and rugose, serving as a protection against
the vicissitudes consequent upon the changeable
medium which they inhabit. In such as are
aquatic the integument is proportionably thin-
ner, and its surface more smooth and even ; in
both, however, it differs much in texture in dif-
ferent parts of the body ; thus in the dermo-
branchiate species it becomes attenuated into a
thin film, where it invests the vascular appen-
dages subservient to respiration, and such por-
tions as cover the organs of sense assume a
transparency and delicacy adapted to the sen-
sibility of the parts beneath. In those orders
which are provided with shells, the integument
which protects such parts of the body as are
exposed when the animal partially emerges
from its abode, is thick and spongy, and very
different from the thin fibrous membrane which
invests the mass of viscera contained within
the shell. We are led by various circum-
stances to presume that the skin of all the
Gasteropods is in structure essentially ana-
logous to that of higher animals, and in de-

* Many of the Capuloid Gasteropods are thought
by Cuvier to be diacious.

t ETtpoc, different; irovf, foot.
$ n»Xuf, many; wXa£, a scale ; <J*?», to carry.
2 c 2

380

GASTEROPODA.

scribing it we shall avoid obscurity by applying
to its different parts the names ordinarily made
use of by anatomists to distinguish the tissues
enumerated as composing the human integu-
ment.

The derwis is an extremely lax and cellular
texture, eminently elastic, and so intimately
blended with the contractile layers beneath it,
that it is difficult to recognise it as a distinct
structure : its great peculiarity consists in the
power which it possesses of secreting calcareous
matter, which being deposited either in a cavity
within its substance, or as is more frequently
the case, upon its outer surface, forms a con-
cealed or external shell : from this circum-
stance, and from the abundant quantity of
mucus which it constantly furnishes, we may
infer its great vascularity, while the high degree
of sensibility which it evidently possesses une-
quivocally demonstrates that it is plentifully
supplied with nerves, although the existence of
a true papillary structure cannot be satisfac-
torily distinguished. The colouring pigment
likewise exists, as is evident from the brilliant
markings which are often met with in some of
the more highly coloured species ; but there is
a circumstance in connection with this rete
mucosum which requires particular mention, as
it will enable us afterwards more clearly to ex-
plain the formation of shells ; the pigment is
not merely a layer which serves to paint the
surface of the body generally, but appears ra-
ther to be an infiltration of the lax tissue of the
ciitis with coloured fluid, which is poured out
in great abundance at particular points, espe-
cially around the margin of the shell, and there
being mixed up with the calcareous matter se-
creted by the collar, its tints are transferred to
tlit; exterior of the shell itself, tinging it with
similar hues. The epidermis is evidently defi-
cient, its place being supplied by the viscid
matter with which the surface of the body is
continually lubricated. The muciparous crypts
destined to furnish the copious supply of glairy
fluid with which the skin is so largely moist-
ened, have not been detected, but the pores
through which it exudes are sufficiently distinct.
It is> in connexion with the needful diffusion of
this secretion over the entire animal, that the
skin of the terrestrial species, as the Slugs and
Snails, is observed to be deeply furrowed by
large anastomosing channels, formed by the
rugae of the surface, and serving as canals for
its conveyance by a species of irrigation to
every point. No pilous system, properly so
called, exists in any of the Gasteropods, the
hairy covering of many shells being, as we shall
presently see, of a widely different nature.

From the modifications observable in the
structure of the integument, it is not to be won-
dered at that names have been applied to diffe-
rent portions, which it will be useful to notice,
especially as they are not unfrequently used in
a confused and unprecise manner. That por-
tion of the skin which is more immediately
connected with the secretion of the shell, in
such Gasteropoda as are provided with a de-
fence of that description, has been termed the
mantle, and in certain instances, from the mode

in which it seems to form a special co\ ering to
a part of the body, it has some claim to the
name ; the mantle is, however, extremely varia
ble, both in position and arrangement. In the
Nudibranchiata, which have no shell, it cannot
be said to exist, as no fold of the integument or
defined margin indicating a portion deserving
of a distinct appellation can be detected. In
the Tectibrunchiata the mantle is a small trian-
gular fold of the integument on the right side of
the body, inclosing a rudimentary shell, and
serving as a covering to the subjacent branchiae.
In the Inferobranchiata it invests the whole of
the back, and forms a fold around the margins
of the body, beneath which the branchiae are
found ; whilst in all the conchiferous Gastero-
pods it lines the interior of the shell, whatever
its shape, forming a distinct fold or thickened
rim around its aperture, to which when much
developed, as in Helix, the name of collar is
not improperly applied.

In the naked terrestrial species the mantle
consists of a thickened portion, occupying a
variable position on the back, and more or less
defined by a distinct margin ; it is here not un-
frequently termed the corselet, and generally
contains a calcareous plate. In Vaginula it
covers the whole of the back ; in Limax it occu-
pies only its anterior portion ; in Parmacella it
is found in the middle of the dorsal region,
whilst in Testacella it is placed quite poste-
riorly in the vicinity of the tail ; yet whatever its
situation, shape, or size, it is the immediate
agent in the formation of the shell, and as such
we have deemed it necessary to be thus precise
in describing the different aspects which it
assumes.

Growth of shell. — The varied and beautiful
shells that form so important a part of the inte-
gument of many individuals belonging to this
order, however they may differ in external form
and apparent complication, are essentially simi-
lar in composition and in the manner of their
growth. These calcareous defences, although
serving in many cases as a support to the ani-
mal, from which important muscles take their
origin, differ widely from the internal skeletons
of vertebrate animals, being mere excretions
from the surface of the body, absolutely extra-
vital and extra-vascular, their growth being en-
tirely carried on by the addition of calcareous
particles deposited in consecutive layers. The
derm is or vascular portion of the integument is
the secreting organ which furnishes the earthy
matter, pouring it out apparently from any part
of the surface of the body, although the thicker
portion, distinguished by the appellation of the
mantle, is more especially adapted to its pro-
duction. The calcareous matter is never depo-
sited in the areolae of the dermis itself, but ex-
udes from the surface, suspended in the mucus
which is so copiously poured out from the mu-
ciparous pores, and gradually hardening by ex-
posure; this calciferous fluid forms a layer of
shell, coating the inner surface of the pre-exist-
ent layers to increase the size of the original
shell, or else is furnished at particular points
for the reparation of injuries which accident
may have occasioned. It is to the investigae.

GASTEROPODA.

381

tions of Reaumur that we are indebted for our
knowledge concerning this interesting process,
and subsequent writers have added little to the
information derived from his researches; in
order, however, to lay before the reader the
principal facts connected with this subject, we
shall commence with the simplest forms of the
process, and gradually advance towards such as
are more complicated and less easily under-
stood.

The shells of the Gasteropoda are of two
kinds, some being entirely concealed within
the substance of the mantle, and consequently
internal, whilst others are placed upon the sur-
face of the body external to the soft integument.
In the former case the shell is uniform in tex-
ture and colourless ; in the latter, its develope-
ment is much more elaborate, and it is not un-
frequently moulded into a great diversity of
forms, and painted with various tints, which are
sometimes of great brilliancy. The internal or
dermic shells are found in many of the pulmo-
nary and tectlbranchiate orders, and possess
but little solidity ; although inclosed in the
substance of the mantle, they are so little adhe-
rent, that when exposed by an incision they
readily fall out of the cavity in which they are
lodged, and from which they are apparently
quite detached. Their substance is generally
calcareous, but in many instances, as in Aplysia,
the shell is of a homy texture, being transpa-
rent, flexible, and elastic, as is the gladius of
many of the Cephalopod Molkuca. In all
cases horny or calcareous plates of this descrip-
tion are found to be composed of superposed
lamellae, which are successively secreted by the
floor of the cavity in which they are contained,
the inferior layer being always the largest and
most recent. These shells, therefore, may be con-
sidered as merely formed by the deposition of
successive coats of varnish, which become indu-
rated, and the simple manner of their growth will
best exemplify the mode in which more compli-
cated shells, whatever be their form, are con-
structed. External shells present an endless di-
versity of figure, and some classification of their
principal forms will facilitate our contemplation
of the peculiarity observable in each. The con-
cealed shells, which are merely the rudiments of
whatwearenow considering,are so small in com-
parison with the size of the body, that they can
only be looked upon as serving for the protec-
tion of the more important organs, namely, the
heart arid respiratory apparatus, which are placed
beneath them, but the external shells, from
their great developement, are not merely a partial
protection to the animal, but in most cases
constitute an abode into which the creature
can retract its whole body. The external shell
consists generally of one piece, the form of
which may be symmetrical, in which case it is
a cone or disc simply covering the back of the
animal ; or, as is generally the case, the shell
may be more or less twisted around a central
axis, forming a convoluted, turbinated, or spiri-
valve shell. In one genus only, Chiton, Lin.,
the shell is formed of several pieces articulated
with each other, and covering the surface of the
back.

The shell of the Patella, a section of which
is represented in jig. \ 78, is a simple cone placed
upon the back of the creature, which it com-
pletely covers, and upon which it is evidently
moulded. On making a section of the animal,
as in the figure, the shell is found to be entirely
lined by the mantle a, 6, by which it is secreted.

Fig. 178.

That the whole surface of the mantle is capable
of secreting the calcifying fluid from which the
shell is formed, is distinctly proved by the
manner in which a fracture or perforation in-
any part is speedily repaired by the deposition
of a patch of calcareous matter beneath it, but
in the ordinary growth of the animal the differ-
ent portions of the mantle execute different
functions. It is obvious that the enlargement
of the body of the patella, as its age increases,
must necessitate a corresponding enlargement
of its habitation, and this is principally effected
by additions of calcareous matter in succes-
sively larger rings around the mouth of the
shell only; the great agent therefore in forming
the shell is the margin of the man tie,. 6, b. This-
hangs loostly as a fringe near the mouth of the
shell, and being moveable at the will of the
animal, the calcareous matter which it pre-
eminently furnishes may be laid on in succes-
sive layers to extend the mouth of its abode ;
and these consecutive additions are indicated
externally by concentric lines running parallel
with the circumference of the shell, the num-
ber of which necessarily increases with age.
Whilst the abode of the creature is thus en-
larged by the deposition of shell from the vas-
cular and spongy margins of the mantle, the
office of the rest of that membrane is reduced to
the increase of its thickness, depositing succes-
sive coatings of calcareous particles, which are
laid on to its inner surface, and when a section
of the shell is made (J'J, these last-formed strata
are readily distinguishable by their whiteness
and different arrangement. So far the produc-
tion of an external shell is entirely similar to
what we have met with in the formation of the
internal defences of the naked Gasteropoda, yet
in other respects the former are much more ela-
borately organised. In the first place many of
them are adorned externally with colours, not
unfrequently arranged with great regularity and
beauty ; these tints belong exclusively to the
outer layers of the shell, that is, to those formed
by the margins of the mantle, and are produced
by a glandular structure appropriated to the
secretion of the colouring matter, which only
exists in the vascular circumference of the cal-

382

GASTEROPODA.

ciferous membrane. The colouring matter
becomes thus incorporated at definite points,
with the cement by which the shell is extended,
and is arranged in various manners according
to the position of the secreting organs which
furnish it. Another peculiarity which distin-
guishes external shells is that their outer sur-
face is often invested with a membranous layer,
called the epidermis, which having been re-
garded by some authors as a part of the true
integument of the body, has given rise to the
supposition that all shells being placed between
two layers of the skin were in fact internal, the
difference between the one and the other con-
sisting merely in the extent of development.
In support of this opinion reference has been
made to the great thickness of this epidermic
coat, which not unfrequently is such as to give
to the surface of the shell a felted or pilous ap-
pearance ; but if such an idea were correct, it
is evident that the epidermis must be formed
prior to the deposit of calcareous matter be-
neath it, which observation has disproved, in-
asmuch as those shells in which the epidermic
covering is most dense and shaggy are found
whilst in ovo to be without such an investment.
The so-called epidermis, therefore, whatever
may be the aspect which it presents, whether it
be, as is usually the case, a brittle lamella en-
crusting the shell, or a flocculent and pilous
covering, is evidently inorganic, being merely a
crust of inspissated mucus, originally secreted
with the calcareous particles, and forming when
dry a layer encrusting the surface of the shell.

There is yet another structure common to
shells of this class, of which it remains to speak,
namely, the enamel or pearl, which lines such por-
tions of them as are immediately in contact with
the body of the animal ; this polished material
may be likened to the glazing of an earthen-
ware vessel, and is a varnish produced from
the general surface of the mantle, by some mo-
dification of its secretion the nature of which
is unknown, and spread in successive coatings
over the more coarse calcareous matter, where-
ever such a polish becomes needful.

Having thus briefly described the origin of the
different parts of a shell in the simple form which
we have chosen as an example, we shall now
proceed to examine the structure and mode of

frowth in others of a more complicated aspect,
'he majority of the Gasteropoda are furnished
with a shell which has been denominated spiri-
valve. Let the reader imagine the shell of the
Patella to be lengthened into a long cone, which,
instead of preserving its symmetrical form, is
twisted around a central axis, and he will imme-
diately understand the general arrangement of
the parts in shells of this description. The cause
of such an arrangement is owing to the shape
of the body of the animal inhabiting the shell,
which, as it grows, principally enlarges its shell
in one direction, thus of course making it form
a spire modified in shape according to the de-
gree in which each successive turn surpasses in
bulk that which preceded it. The axis around
which the spire revolves is called the coktmeUa,
and the mode of revolution around this centre
gives rise to endless diversity in the external

form. In the spirivalve-shelled Gasteropoda,
as in those last described, we find a difference in
structure between that part of the mantle which
envelopes the viscera, and is always concealed
within the cavity of the shell, and the more
vascular portion placed around its aperture :
the former is thin and membranous, its office
being merely that of thickening the shell by
the deposition of successive calcareous strata
applied to its inner side, and of producing the
pearly lining which smooths and polishes the
interior ; the latter part of the mantle is thick,
spongy, and coloured, secreting largely the cal-
careous particles with which the progressive
amplification of the shell is effected : this por-
tion (Jig. 179, c,J from its thickness, and the

Fig. 179.

manner in which it usually surrounds the en-
trance to the shell, is generally termed the col-
lar. In such species as inhabit coloured shells
we may observe upon the surface of the collar
(Jig. 179, d,) patches of different colours corres-
ponding in tint with the various hues seen upon
the exterior. These spots supply the pigment,
which being mixed up with the earthy cement
serving for the enlargement of the shell stains
it with a corresponding tint. In many instances,
as in the figure, the colours are continually
secreted by the dark spaces, d, causing the
painted bands which they produce to wind un-
interruptedly in the direction of the convolu-
tions of the spire, and they may be seen gra-
dually to increase in breadth as the size of the
animal enlarges : but more frequently it happens
that the colouring matter is only furnished at
stated periods, and in such cases of course the
shell will be marked with spots, the intervals be-
tween which will be regulated by the frequency
of the supply. It will be seen that by a combina-
tion of these circumstances it is easy to explain
how every variety of marking may be produced.)
The most conspicuous exception to the gene-
ral process by which shells are painted, is met
with in the porcellaneous Couries ( Cyprcea),
which at various periods of their growth could
scarcely be recognised as belonging to the same
genus. In the young animal the enlargement
of the shell is effected in the ordinary manner,
and its colours are supplied from the surface of
the collar : in the mature state, however, these
shells are coloured in a very different manner,
and acquire at the same time a great increase of
thickness ; this is effected by the enormous de-
velopment of the alae of the mantle, which in
the full-grown animal become so much ex-
tended, that when the creature is in motion they
are laid over the external surface of the shell so
as entirely to conceal it. These alae contain
patches of pigment which secrete colours en-
tirely different from those contained in the
collar, arid from their whole surface exudes a

GASTEROPODA.

383

calcareous varnish, which being laid over the
exterior of the old shell completely conceals
the original markings ; these, however, may be
again exposed on removing with a file the outer
crust: a line, which is generally very distinctly
seen running longitudinally along the back of
the shell, indicates the spot where the edges of
the two alae of the mantle met during the com-
pletion of this singular process. Such shells
are therefore remarkable from the circumstance
of having their thickness increased by additions
to the outer as well as to the internal surface.

In terrestrial shells it is only when they have
arrived at their full growth that a rim or margin
is formed around the aperture, which serves to
strengthen the whole fabric; but in marine
shells, which attain to much larger dimensions,
the growth is effected at distinct periods, each
of which is indicated by a well-defined margin,
and these ridges remaining permanent, the suc-
cessive stages of increase may be readily seen.
At each suspension of development, it is not
unusual to find spines or fringes, sometimes
differently coloured from the rest of the shell,
and not unfrequently of considerable length.
In Jig. 180, which represents the shell of Murex

Fig. 180.

cornutus, the nature and arrangement of such
spines is well exemplified. They are all formed
by the margin of the mantle which shoots out
into long fringes, encrusting themselves with a
shelly covering ; each spine therefore is at first
hollow, and if in many species they are found
solid, it is because the original cavity has been
gradually filled up by the deposition of earthy
matter within it. The syphon with which many
Conchiferous Gasteropoda are provided is pro-
duced in precisely the same manner, and its
identity in form with the other spines covering
the surface of the shell is in the annexed figure
sufficiently obvious. In many species, as in
the beautiful Turbo scalaris, (Jig- 181,) the
epocha of growth are only indicated by ridges
surrounding the shell at regular intervals, each
of which originally terminated a fresh augmen-
tation of its size. It is difficult to imagine by
what influence these creatures are induced to
enlarge their habitations at such regular inter-
vals, terminating each operation by a similar
margin ; some authors imagine that each time
the creature emerges from its abode a fresh
addition is made ; others that it is dependent
upon the temperature or state of the seasons,
but without sufficient grounds for either of these
assertions ; it seems more probable therefore
that the growth of the body gradually rendering
the former dimensions of the shell incommo-

dious from time to Fig. 181.

time renders these pe-
riodical enlargements
necessary.

Although shells
are evidently inorga-
nic and extra-vascu-
lar structures, it is
now universally con-
ceded that their in-
habitants have the
power of removing
portions which may
obstruct their growth,
or needlessly infringe
upon the limits of
their abode. In the
Murices we have in-
disputable evidence
of this fact in the
removal of such spines as would interfere
with the revolutions of the shell around the
columella, and in Conus and similar genera
a like faculty enables the animals to thin
the walls which bound the inner whirls
when their original thickness is rendered un-
necessary by the accession of new turns. Such
a solvent power indeed is not only exer-
cised upon their own habitations, but many
Gasteropods are able gradually to bore holes in
other shells, or perforate the rocks upon
which they reside to a considerable depth.
The mode in which this is effected is, however,
still a mystery ; some authors ascribe it to a
power of absorbing their shells, an expression
the vagueness of which is sufficiently evident ;
others ascribe it to some acid secretion at the
disposal of the animal ; yet although this ex-
planation is certainly plausible, when we reflect
that the very structure which secretes this sup-
posed acid is itself the matrix of such abundant
alkaline products, it is not easy to imagine how
the same structure can at the same time furnish
such opposite materials.

As we should expect from the mode of its
growth, the shell throughout all the Conchi-
ferous class is composed of earthy matter,
cemented together by an animal substance
easily separable by the action of acids. In the
porcellaneous shells the animal matter exists in
much less quantity than in those of a fibrous
texture ; in the former, indeed, Mr. Hatchett
found that when the carbonate of lime, of
which the earthy portion is almost entirely
formed, is dissolved even by very feeble acids,
little or no vestige of any membranous struc-
ture could be perceived, nor indeed could any
be detected, but by the small portion of animal
coal which was formed when these shells had
been exposed for a short time to a low red
heat ; in others however, as the Patellae, a sub-
stance was left untouched by the acids which
had the appearance of a yellowish transparent
jelly, by means of which the earthy matter
had been, as it were, cemented together.

On examining minutely the mechanical ar-
rangement of the layers of which these shells
are composed, it is found to vary in different
kinds, and from this circumstance the fossil

384

GASTEROPODA.

conchologist may derive important information
in examining mutilated remnants sometimes so
plentifully met with in calcareous strata. The
simpler shells (Patella, Fissurella) are formed
of very thin, compact, and parallel layers,
whilst in others three distinct strata of fibres,
each of which assumes a different direction,
may be observed. The fibres composing the
external layer are disposed perpendicularly to
the axis of the shell. In the middle stratum
the fibres are placed obliquely and are slightly
twisted, but so arranged that each meets at an
obtuse angle the extremity of one of the fibres
composing the outer layer, and in the internal
stratum they again assume a perpendicular
direction. Such a disposition of the fibres,
which is met with in all Siphonibranchiate
shells, is eminently calculated to resist ex-
ternal violence in whatever direction it may
act, and greatly contributes to the solidity of
the whole fabric.

Operculum. — Many of the spirivalve Gaste-
ropoda, especially such as are aquatic, are
provided with a calcareous plate, which is
placed upon the posterior surface of the body,
and closes accurately the mouth of the shell,
when the animal is retracted within it. The
texture of the operculum is sometimes horny,
but it is more frequently calcareous and of a
stony hardness, its contour being accurately
adapted to the orifice. It is composed of
parallel fibres disposed perpendicularly to the
base of the shell, and deposited in successive
layers around an axis, so as to give to the
whole structure the appearance of a solid
spirivalve, as may readily be seen on removing
it from the animal and examining its inner
surface. This has been looked upon by some
zoologists as analogous to the second valve of
bivalve Mollusca, to which, but for its want
of a ligamentous attachment, it certainly bears
a distant resemblance.

The deciduous operculum of terrestrial
Gasteropoda, or epiphragma, as it is usually
called, is a widely different structure, being
merely an inspissated secretion, with which,
during the period of hybernation, the entrance
to the shell is closed ; and on removing the
outer plate, not unfrequently a second or even
a third similar membrane will be found within,
forming additional safeguards against intrusion
or the vicissitudes of temperature.

During the progressive growth of the shell
the animal contained within it necessarily
changes its original position, advancing gra-
dually as the body enlarges from the earliest
formed spires towards the aperture, as may
easily be proved by sawing off the apex of a
spirivalve shell containing the living animal.
This circumstance is remarkably conspicuous
in some of the Bulimi (Bulimus decollatus),
enabling the occupant, as it grows, to break
off the turns of its spire which first contained
it, so that at the latter period of its life it does
not retain any part of its original shell. The
mode in which this advancement is effected is
a subject of much curiosity, as it involves a
power of detaching the muscles connecting
the creature with its abode, from the place

where they were originally fixed, and forming
a new connexion with the shell ; but whether
this is effected by the removal of the original
fibres and the production of others more ante-
riorly, as is believed by some, or whether, as is
more probably the case, the creature has a
power of changing the attachment of its re-
tractor muscle at pleasure, is still a matter of
uncertainty.

Organs of digestion. — We shall not be sur-
prised to find that in a class so extensive, and
composed of individuals living in such diver-
sified circumstances, the alimentary organs are
much modified in form in different species,
according to the nature of the food with which
they are nourished.

Mouth. — In most instances the mouth pre-
sents the appearance of a retractile proboscis,
which can be protruded or shortened at the
will of the animal, but unprovided with jaws
or any apparatus for mastication ; it is in such
cases a muscular tube, formed of longitudinal
fibres prolonged from the common parietes of
the body, and of circular muscles, the former
serving for the retraction of the organ, the
latter causing its elongation by their successive
action; by means of this simple structure
every movement requisite for the prehension
of food is effected. At the bottom of the tube
is a narrow vertical aperture, the edges of which
are slightly cartilaginous, and behind this is
the tongue armed with spines variously dis-
posed ; the aliment therefore, having been
forced by the contractions of the proboscis
through the aperture at its termination, is re-
ceived by the tongue, and by the aid of the
latter organ is propelled into the oesophagus
without mastication or any preparatory change.

In Buccinum and other syphoniferous ge-
nera, the structure of the proboscis is much
more complicated and curious, (jig. 182.)
" The proboscis, which carries with it the
oesophagus in its different states of protrusion,
is organised with wonderful artifice, being not
only capable of flexion in every direction com-
bined with limited power of retraction or
elongation, but it can be entirely lodged in the
interior of the body, folded within itself, so
that that half which is nearest the. base en-
closes the other portion : from this position it
is protruded by unfolding itself like the finger
of a glove or the tentacle of a snail, only it is
never completely inverted. We may repre-
sent it as composed of two flexible cylinders
(Jig. 182, a, 6,) one inclosed within the other,
the upper borders of which join, so that by
drawing outwards the inner cylinder, it is
elongated at the expense of the other, and
on the contrary, by pushing it back, the internal
cylinder becomes lengthened by its shortening.
These cylinders are acted upon by a number
of longitudinal muscles (c, c), all very much
divided at each extremity, the internal or su-
perior divisions being fixed to the parietes of
the body, whilst at the other end they are
attached to the inner wall of the internal tube
(«) of the proboscis, along its whole length,
extending even to its extremity ; their action is
obviously to draw the inner cylinder, and con-

GASTEROPODA.

385

Fig. 182. sequently the entire

proboscis inward. This
being done, a great
part of the inner sur-
face of the inner cy-
linder becomes a part
of the external surface
of the outer cylinder,
whilst the contrary oc-
curs when the pro-
boscis is elongated and
protruded.

The elongation of
the inner cylinder by
the unfolding of the
outer, or what is the
same thing, the pro-
trusion of the probos-
cis, is effected by the
intrinsic annular mus-
cles which assist in
forming the organ ;
they surround it
throughout its whole length, and by their suc-
cessive contractions force it outwards; one espe-
cially, seen at b, placed near the junction of the
extremity of the outer cylinder with the inte-
guments of the head, which is stronger than
the rest. When the proboscis is protruded,
its retractor muscles acting separately, bend it
in every direction, being in this case antago-
nists to each other. The internal cylinder
incloses the tongue (f), the salivary canals (<?),
and the greater part of the oesophagus (d), but
its principal use is to apply the extremity of
the tongue to such objects as the animal would
suck or erode by its armed surface.

In Aplysia, Akera, and others, the mouth,
consists of a fleshy mass of considerable
strength, to which are attached muscular bands
proceeding from the sides of the body, serving
for its movements, some drawing it forwards
whilst others retract it, but there are no jaws
nor anything equivalent to them, except the
cartilaginous hardness of the lips.

But in such of the Gasteropoda as devour
vegetable matter, the mouth, instead of being
a proboscis, consists of a strong muscular
cavity, inclosing a dental apparatus adapted to
the division of the food. In the Snail, Slug,
Limnaeus, Planorbis, &c., this is a single cres-
cent-shaped horny tooth, attached to the upper
surface, and furnished along its opposite edge
with sharp points, separated by semicircular
cutting spaces, admirably adapted for the di-
vision of vegetable food.

The dental organs of Tritonia and Scylloea
are, however, still more perfectly contrived for
such a purpose. The muscular mass of the
mouth is strong and powerful, but instead of
the single tooth of the Snail, it is armed with
two cutting blades (fig- 183, b, 6), horny in
their texture and exceedingly sharp, resembling
in every respect a pair of strong curved shears,
from which in fact they only differ in the mode
of their union, the spring of the one being
replaced by an articulation (c) inclosed in a
synovial capsule. These blades are approx-
imated by strong muscular fibres, and few

Fig. 183.

animal structures can resist their edge. The
lips (A), which are placed in front of these
teeth, are strong and very flexible, forming
a muscular tube, by means of which the food
is seized and brought within the power of its
formidable jaws, and then the divided morsels,
being seized by the horny teeth which invest
the tongue (d), are conveyed into the oesopha-
gus.

Tongue. — The tongue in these Mollusca is
generally a very important organ, serving not
only as a necessary auxiliary in deglutition, but
often as a means of eroding the food : in fact,
in one tribe only, T/iet/iys, is it found to be
deficient. In most of the proboscidean spe-
cies the tongue is short, and covered with
sharp, horny, and recurved spines, which,
seizing the morsels of food taken into the
mouth by a sort of peristaltic motion, push it
backwards into the oesophagus. In some ge-
nera which have no proboscis, the tongue is
of extraordinary length ; thus in Haliotis it
is half as long as the body, and in Patella,
Turbo, Pica, and others, it much exceeds in
length the entire animal. The tongue of Pa-
tella, which is three times the length of the
body, is represented at fg. 184 ; it is supported
by two cartilaginous pieces (6, ft) placed on each

Fig. 184.

side of its root; from these arise strong and
short muscular bands, which wield the or-
gan. The surface of this singular tongue,
a magnified view of which is given at B,
is armed with minute though strong teeth,
placed in transverse rows and arranged in
three series; each central group consists
of four spines, while those on the sides con-
tain but two a-piece. It is only at its an-
terior extremity, however, that the tongue so
armed presents that horny hardness needful
for the performance of its functions, the posterior

386

GASTEROPODA.

part being comparatively soft ; it would seem,
therefore, that in proportion as the anterior part
is worn away, the parts behind it assume
gradually the necessary firmness and advance
to supply its place. The action of this curious
instrument is as follows : — in the upper part
of the circumference of the mouth we find a
semicircular horny plate, resembling an upper
jaw, and the tongue, by triturating the food
against this, gradually reduces substances how-
ever hard. On opening the Patella, the tongue
is found doubled upon itself, and folded in a
spiral manner beneath the viscera.

The tongue of Oscabrio resembles that of
the Patella, except in its armature, being fur-
nished on each side with a series of hooked and
three-pointed scales, and another set of long,
sharp, and recurved spines, whilst its centre is
simply studded with tubercles. In Turbo pica
the scales, which are cutting and denticulated,
are arranged transversely along its surface.

The tongue of Buccinum (Jig. 182, f), is
placed at the extremity of the proboscis, form-
ing a most extraordinary apparatus, capable of
destroying by its constant action the hardest
shells ; externally it resembles rather a mouth
than a tongue, being divided into two lips,
each of which is studded with sharp horny
teeth. These lips are supported upon two
cartilages which occupy the anterior half of the
proboscis, and are moved upon each other by
strong muscular fasciculi (A) in such a manner
that the spines which arm the surface of the
organ are alternately erected and depressed by
their action, a movement the constant repe-
tition of which soon wears away the substances
upon which it is made to act. This spiny
tongue is situated just within the entrance to
the oesophagus (cT), and besides acting upon
foreign bodies will materially assist in pro-
pelling the food into that tube.

In other Gasteropods the tongue is short
and merely an organ of deglutition : thus, in
Aplysia it is broad, heart-shaped, and studded
with sharp points. In Onchidium and Doris,
the surface is marked with transverse grooves,
which are crossed at right angles by others of
great fineness. And in the Snail and Slug, in
which the surface of the tongue is similarly
marked, the striae are so delicate that they can
only be seen with a microscope.

Alimentary canal. — We shall commence
our description of the intestinal canal of the
Gasteropod Mollusca by the examination of
the simpler forms which it presents. In the
Snail (jig. 190), the whole alimentary tube
(e, /, g, k) is thin and membranous. The
stomach, which is merely a dilatation of the
oesophagus, is semitransparent, but studded
with opaque points and internally folded into
delicate longitudinal plicae. From this arises
an intestine, of considerable length, without
coeca, valves, or remarkable appearance inter-
nally, except near its termination, where the
orifices of minute follicles may be detected ;
the intestine having performed several con-
volutions enveloped in the masses of the liver,
with which it is connected by cellulosity
and numerous vessels, at last runs along the

margin of the pulmonary cavity, close to the
orifice of which it terminates. In Vaginulus
the arrangement is nearly similar (Jig. 189,
g, A, z.) In Tritonia and Doris the structure
of the digestive tube is equally simple, and in
these as well as in the majority of the Gaste-
ropoda the only remarkable differences are
found in the proportional size of the stomach
and the length of the intestinal convolutions.
In Doris we find near the orifices by which
the bile is poured into the stomach, an aper-
ture communicating with a round vesicle or
coecum, the inner surface of which is evidently
glandular, and from its large supply of blood
derived from one of the hepatic arteries, pro-
bably furnishing an abundant secretion ana-
logous to that of the pancreas. In Phasia-
nella the stomach is very voluminous and
sacculated internally. In Buccinum the di-
gestive apparatus is more complicated in its
structure. The oasophagus commences, as we
have already seen, at the extremity of the pro-
boscis, and of course follows all the motions
of that organ ; when the proboscis is protruded
in search of prey, the gullet is straight and
adapted to the reception of food ; but when the
proboscis is retracted within the body, the
oesophagus is bent upon itself, so as to be
partially contained within the proboscis, whilst
the greater portion is folded beneath that organ
in its retroverted state. After making another
fold it dilates into a small crop, the lining of
which is plicated in the direction of its axis,
and to this succeeds the stomach, which is a
moderately sized round cavity, irregularly ru-
gose internally. The intestine is very short,
and has a small coacum appended to its side ;
it terminates in a capacious rectum, placed,
as is invariably the case, in the vicinity of the
respiratory cavity, and having its lining mem-
brane gathered into prominent longitudinal
rugse. Many of the Gasteropoda are provided
with several digestive cavities, resembling in
some degree the stomachs of ruminating Mam-
malia. In Janthina, which is furnished with
a proboscis like that of the Buccinum, the
oesophagus arising from this terminates by a
narrow slit in a membranous cavity or first
stomach, to which succeeds a second, having
thicker walls and plicated internally. The in-
testine is extremely short, terminating as usual
in the neighbourhood of the respiratory cavity.
In Pleurobranchus the resemblance of the
stomachs to those of a ruminating quadruped
is very striking. The first stomach (fig. 185,
a), which is membranous, receives the bile by
a large orifice (6) placed near its communi-
cation with the second digestive cavity (c),
which is smaller and more muscular ; to this
succeeds a third (d\ the sides of which are
gathered into broad longitudinal lamellae, pre-
cisely similar to those of a ruminant ; and
to render the analogy still more perfect, a
groove is found running along the walls of the
second cavity from one orifice to the other,
apparently subservient to rumination. The
fourth stomach (e) is thin, and its walls smooth.
This animal lives on Alcyonia and small Zoo-
phytes.

GASTEROPODA.

387

Fig. 185.

similar

that

Many Gasteropoda which
devour shell-fish and other
hard materials have a true
gizzard adapted to break in
pieces such food ; this is the
case with Thethys, an animal
whose mouth is' totally desti-
tute of dental organs, but
their want is supplied by a
fleshy gizzard resembling that
of a bird, having its interior
lined with a dense cartilagi-
nous membrane, like that
which lines the gizzard of
graminivorous fowls, and in
its cavity shells of Mollusca
and Crustaceans are found
comminuted by its action.
In Limn<Eus we find a gizzard
strictly analogous in structure
to that of a granivorous bird :
it presents two dilatations,
one at the cardiac, the other
at the pyloric extremity,
whilst the middle portion is
occupied by two strong mus-
cles, united at the sides by
tendinous bands. The gizzard
of Planorbis is precisely
of Limnaeus. In Onchidium
the muscular gizzard is followed by two other
stomachs, the lining membrane of that which
immediately succeeds it being gathered into
large folds, which must greatly retard the pas-
sage of the aliment; while the third cavity,
which is short and cylindrical, is likewise lined
with a membrane folded into more delicate
plicae, affecting a longitudinal direction.

There are some families in this class which
are provided with a still more elaborate appa-
ratus for the preparation of their food, their
stomachs being armed internally with teeth
variously disposed, and on many accounts
extremely curious. In all the Bullae (Akera)
the gizzard contains three plates of stony hard-
ness attached to its walls, and so disposed that
they are evidently powerful agents in the tritu-
ration of the food. In Eulla lignaria (jig. 186)
Fig. 186. two of these teeth are placej
on either side of the gizzard,
into the cavity of which they
project, and are united to
each other by strong muscular
bands ; the third piece is
smaller than the other two,
but similarly imbedded in
radiating muscles, whose
action must powerfully gr.nd
down the substances which
come under the influence of
this singular mill. In the other BuHa the
structure of the gizzard is the same, but the
bony plates differ slightly in form and arrange-
ment. In all, however, the fragments of shells
and other hard substances found in it attest the
efficacy of the apparatus.

The gizzard of Scyllaa (jig. 187, e) is, ex-
ternally, a strong fleshy cylinder, and when
this is opened there are iband, firmly im-

bedded in its muscular walls, twelve horny
plates, which are extremely hard and as sharp
as the blades of a knife ; their edges are dis-

posed in the direction of the axis of the organ,
and as they project considerably into its cavity,
their action upon the contents of the gizzard
must be sufficiently evident.

Aplysia, however, furnishes us with the
most curious form of these stomachal teeth.
The oesophagus, which is comparatively narrow
at its commencement, soon dilates into a capa-
cious crop, which is generally found filled with
pieces of fucus and the fragments of shells. To
this crop succeeds a short cylindrical gizzard with
strong and muscular walls, and after the gizzard
we find a third stomach which leads to the
intestine. On opening the gizzard and third
stomach (jig. 188) they are found to have their

Fig. 188.

388

GASTEROPODA.

interior armed in a manner which is probably
unique. The sides of the gizzard (b) are
covered with pyramidal plates of a rhomboidal
figure, the apices of which resemble the
tubercles found upon the grinding surfaces of
the human molar teeth. Of these there are
twelve larger plates arranged in quincunx,
besides several smaller ones placed near the
entrance of the organ. These teeth are of a
horny nature and formed of laminae parallel to
their bases : their adhesion to the surface of
the lining membrane is so slight that they are
detached by the slightest effort, without leaving
any trace of membrane or other bond of union,
the place of their attachment being only indi-
cated by a smooth and prominent surface,
corresponding in shape to the base of each
tooth. The apices of all these teeth meet in the
centre of the gizzard, and whatever passes
through that cavity must be bruised by their
action.

The third stomach (d) is armed with teeth of
a totally different nature. These are little
conical hooks (c) attached to one side of the
organ only, and as little adherent in the dead
animal as are the pyramids of the gizzard
towards which their points are directed. In
the figure many have fallen off, leaving slightly
elevated spots indicative of the place of their
attachment. Near the pylorus is a large aper-
ture communicating with a ccecum of consider-
able size (y), evidently identical with the
spiral cfficum of the Cephalopoda both in its
position and relation to the insertion of the
biliary canals (e\ forming, as in Fishes, the
rudiment of a pancreas. From the orifice of
the ccecum a ridge is prolonged into the com-
mencement of the intestine (g).

Accessory glands. — The auxiliary chylopoietic
secretions found in the Gasteropoda are gene-
rally only two, the salivary and the hepatic.
In some rare instances already adverted to, as
in Doris and Aplysia, we may likewise add
the pancreatic furnished by the cceca, which in
those genera terminate in close vicinity with
the ducts issuing from the liver, and which,
from every analogy, represent the pancreas of
vertebrate animals.

The salivary glands are constantly present
and seem to present a size and importance
corresponding with the mode in which the
mastication of the food is accomplished. In
those genera which are provided with a cutting
apparatus placed in the mouth, they are very
largely developed, as also in most of the
pioboscidean species, and it is only in the
Cyclobranchiate order, where the long spiral
tongue is used rather for the abrasion than the
mastication of the food, that they become small,
and, in a very few instances, undistinguishable.
In^/rg. 190, which represents the viscera of the
Snail, these glands are marked with the letters
« *, and this engraving will give a good idea of
the general structure which they present, and of
the ordinary termination of the ducts which pour
the saliva into the oral cavity. The glands
are placed along the sides of the stomach,
which they partially invest, and sometimes
those of the opposite sides are intimately united

with each other; their colour is whitish and
semi-transparent, and they are formed of small
lobes, which, in many species where their
texture is less compact, may be distinctly seen
to be formed of the ramifications of their
arborescent ducts, each ultimate division of
which is term mated by a secreting granule.
In Vaginulus (Jig. 189) the salivary glands are
small, but in addition to the ordinary struc-
ture (J') we find an additional tube or slender
ccecum (*/'), which, lying at first upon the
stomach, passes through the nervous collar to
join the duct by which the saliva is discharged.
The secondary divisions of the ducts gradually
unite to form an excretory canal for each of the
two glands, which invariably pour the salivary
secretion into the mouth in the vicinity of the
tongue. When very small, as in Testacella,
Onchidium, and Haliotis, they are found to be
merely arborescent tufts placed on each side of
the oral mass. In all the Pectinibranchiate order,
where the mouth is converted into a protrusible
proboscis, the glands themselves (Jig. 182, i)
are found within the visceral cavity, and their
ducts (e, e) are very long and tortuous so as to
follow the movements of the proboscis in which
they are lodged, running in contact with the
oesophagus to open at the extremity of that
tube on each side of the spiny tongue ; it is
even probable that the secretion which they
furnish at that point may assist, in some mea-
sure, in the destruction of the shells and other
hard bodies, which are submitted to the con-
tinued action of this organ.

In Darin and P leu.ro branch us a glandular
structure of considerable size is found near the
commencement of the oesophagus, which is of
a brownish colour and plentifully furnished
with bloodvessels. This has been looked upon
as an auxiliary salivary organ, but as its duct
has not been as yet satisfactorily traced, its real
nature is unknown : but in Junthma there are
distinctly four salivary glands, each furnishing
a distinct duct; two of these run, as in Bucci-
num, to the extremity of the proboscis, whilst
the other pair empties the secretion of the
corresponding glands into the commencement
of the oesophagus.

Biliary system. — The liver throughout the
whole class is of great comparative size, en-
veloping the convolutions of the intestines and
filling a large portion of the visceral cavity.
That of the Snail consists of four large lobes
(fig- 190, h), each divisible into lobules, and
these again into secreting granules, from each
of which issues an excretory duct. The ducts
gradually unite into larger trunks, so that the
whole organ, when unfolded, accurately repre-
sents a bunch of grapes, the stem of which would
be the common biliary duct. In the same ani-
mal the excretory ducts from each of the divisions
of the liver unite into one canal, which opens into
the pyloric extremity of the stomach (g) in
such a manner that as much bile must be
poured into the stomach itself as into the com-
mencement of the intestine. In the Slug the
liver consists of five lobes, and from these are
derived two distinct biliary canals, which open
separately into the intestine, one on each side

GASTEROPODA.

389

of the pylorus. A similar disposition occurs
in Faguwlta (fig. 189, /, ti ).

Fig. 189.

In Scylltfa the liver (fig. 187, d) is divided
into six small and detached round masses, the
excretory ducts of which open above the point
where the oesophagus joins the singularly armed
gizzard (c). The liver of Aplysia is very large
and forms three principal masses, among which
are seen the convolutions of the intestine. The
biliary canals are very wide and open into the
third stomach near the aperture communicating
with the rudimentary pancreas (Jig. 188, e).
In Testacella Haliotoidea there are two livers
perfectly distinct from each other, and from
each arises a proper duct, which opens sepa-
rately into the commencement of the intestine
near its origin. Onchidinm furnishes us with
a still more curious arrangement, being pro-
vided with three distinct livers, pouring their
secretions by separate canals into different parts
of the alimentary tube. Each portion perfectly
resembles the others in external appearance,
and in structure as well as in the nature of
their respective secretions. The excretory canal
which proceeds from the largest mass enters
the oesophagus, discharging itself near to its
cardiac termination ; the duct of the second
terminates near the same point, whilst the bile
produced by the third is poured into the
gizzard itself. The insertion of the two former
above the gizzard would seem intended for the
same purpose as the abundant secretion which
is poured into the ventriculus succenturiatus of
Birds, namely, to moisten the food before its in-
troduction into the gizzard ; it is, however, sin-
gular to find the biliary fluid employed for this
purpose ; nor is the insertion of the third duct
into the first of the three stomachs of this animal
less extraordinary, a similar arrangement occur-

ring only in a few fishes, as in the Diodon
Mola.

The liver of Doris is very large, and not
only is the bile which it secretes discharged by
large and numerous ducts into the stomach, so
wide, indeed, that it is difficult to conceive
how the food is prevented from entering them,
but moreover the liver furnishes a second duct
of large calibre, which opens externally in the
vicinity of the anus. A part of the bile in this
case is evidently excrementitious, as there is
no doubt that the second canal takes its origin
from the substance of the liver. " This," says
Cuvier speaking upon this subject, " is the
first instance of the kind which I have met
with, and the fact was sufficiently singular to
make me hesitate long and examine the matter
with all possible precaution before admitting
it. It is only by one supposition that it can
be explained otherwise, — namely, that the lobes
of two different glands are so interwoven that
they are not to be distinguished from each
other, one portion producing bile used in the
process of digestion, and the other secreting a
fluid which escapes by the canal in question."
Before its termination externally, the secondary
duct communicates by a short canal with a
lateral receptacle, which forms a kind of gall-
bladder, having its lining membrane much
corrugated and its walls apparently muscular ;
this is probably a reservoir for the excremen-
titious fluid, in which it may be retained until
the animal feels its discharge necessary. There
is reason to suspect that the fluid thus furnished
is a colouring matter, used as a means of de-
fence, and expelled like the ink of the cuttle-fish
on the approach of danger, but the matter is
undecided.

The bile is in all cases produced from arte-
rial blood, and the liver is provided with but
one system of veins answering to the hepatic.

Organs of respiration. — The respiratory or-
gans of the Gasteropoda are found to be con-
structed upon very various principles, adapted
to the medium which they inhabit, or the pecu-
liar exigencies of the individuals composing
each order. Nevertheless in different groups
allied by the generalities of their organization,
the respiratory system is, in most instances,
found to be constructed upon the same plan,
and this circumstance more than any other has
rendered the position and nature of the respira-
tory organs the most eligible basis of classifica-
t.on. On looking over the table which we
have given at the commencement of this ar-
ticle, the reader will perceive at once that the
names by which the different orders are desig-
nated indicate the general disposition of the
pulmonary or branchial appendages, and we
shall therefore follow the arrangement there
adopted in considering more minutely the pe-
culiarities belonging to each.

The first or Nudibranchiate order is distin-
guished by having the breathing apparatus per-
fectly exposed to the influence of the surround-
ing medium, which in all the genera belonging
to this division is the water of the ocean ; the
branchiae constantly assume the shape of arbo-
rescent tufts, placed in different situations upon
the dorsal aspect of the animal. In Doris (see

390

GASTEROPODA.

article CIRCULATION, fg. 321, vol. i. p. 649,)
they form a circle around the anus. In Trito-
nia they are disposed in two rows along the
sides of the animal, extending from one extre-
mity of the body to the other. In Scylltea they
consist of little tufts irregularly disseminated
over the surface of the back and upon the fleshy
alae projecting therefrom. In Glaucus they form
on each side three large and palmated fins,
being used as agents of progression as well as
instruments for the purification of the blood.
In (Eolisthe branchiae assume the shape of long
riband-like lamella disposed in imbricated
rows ; but whatever their form their structure
is essentially the same, each tuft or lamella
containing the ramifications of the branchial
vessels, and effecting the oxygenisation of the
blood by the extent of surface which they ex-
pose to the action of the surrounding water.

In the Infero-branchiata the respiratory tufts
or plates are arranged around the circumference
of the body, lodged in a deep groove between
the margin of the foot and the edge of the man-
tle which covers the back. The Tectibran-
chinta have the branchiae covered by a little
fold or operculum formed by a duplicature of
the skin, and generally containing a horny or
calcareous plate ; beneath this are seen the re-
spiratory leaflets arranged in rows upon the
two sides ofasemi-crescentic membrane : their
structure in Aplysia is represented in Jig, 191.
Each branchial lamella (a, a} divides dichoto-
mously into smaller plates until the divisions
become extremely minute; the ramifications of
the arteries and veins within them being dis-
tributed to each are spread over an extent of
surface adequate to the efficient aeration of the
circulating fluid which they contain. The
principal trunk of the branchial artery (c) runs
along the concave margin of the crescentic
membrane, while the large venous trunk occu-
pies the opposite or convex border ; the veins
from the branchiae all terminate in this great
vein, their orifices being disposed in circles, as
seen at d.

The Pectinibranchiate order includes that
large family of aquatic Gasteropods which are
enclosed in shells, and the arrangement of the
whole of their breathing apparatus is adapted
to the respiration of w.iter. The branchiae re-
semble in structure those of fishes, and are pec-
tinated or composed of parallel laminae disposed
like the beards of a feather, and attached in two
or three rows to the roof of a large cavity placed
under the integuments of the back ; or else in
some rare cases, as in the Valvata cristata, the
branchia is single, resembling a pen, and floats
externally.* A very material difference is ob-
servable between the truly aquatic species and
the pulmonary Gasteropods which inhabit the
water, but breathe air ; in the latter, which are
compelled to come to the surface to respire, the
aperture leading into the pulmonary cavity is
small and furnished with a powerful sphincter,
so that the air taken in is retained at the plea-

* For a figure of the branchial chamber of the
Buccinum undatum, and an account of the ciliary
movements which have been observed in many
orders of Gasteropoda to be connected with respi-
ration, the reader is referred to the article CILIA.

sure of the animal ; but in those which are pro-
vided with pectinated branchiae, the entrance to
the branchial chamber is a wide fissure, always
allowing free ingress and egress to the circum-
ambient fluid. Many genera of this order are
provided with a special apparatus called the sy-
phon, for conveying the water freely into the re-
spiratory chamber ; this is a semi-canal formed
by a fold of the right side of the mantle, and
lodged in a groove projecting from the mouth
of the shell ; through this channel the water at
all times has free admission to the gills. The
respiratory organs of the Scutibranchiata re-
semble those of the last order, and are contained
in a similar cavity, to which the water is con-
stantly admitted ; but in the Cyclobranchiata
the branchiae consist of a series of lamellae
placed external to the body, around the border
of the mantle, by the edge of which they are
overlapped.

Respiration is effected in the Pulmonary
Gasteropoda, whether they be terrestrial or
aquatic, by an apparatus fitted for breathing the
air of the atmosphere ; the lung or pulmo-bran-
chia, as we may call this singular organ, con-
sists of a large cavity placed beneath the man-
tle, over the surface of which the vessels return-
ing the blood from the system spread in beau-
tiful ramifications, and from these the pulmo-
nary veins take their origin, collecting the blood
which has been exposed to the action of the
air, and conveying it to the heart. A large
orifice admits the air freely into this chamber,
the walls of which alternately contracting, draw-
in and expel it at regular intervals by an action
precisely similar to that of the human dia-
phragm. In the Slugs (Limax) the cavity is
small, but the network of the vessels spreads
over its whole surface. In the Snail (Helix),
on the contrary, the organ is much larger, but
its floor only is covered with the respiratory
ramifications. In Jig. 322, of the article CIR-
CULATION, vol. i. p. 649, a diagram is given
of this structure, and in jig. 190, (m, w,) the
details of its arrangement are more minutely
shewn; yet even in the beautiful drawing
of Cuvier, from which our plate is copied,
the minute divisions of this superb plexus
are but inadequately shewn. The order which
has been established by Ferussac, under the
name of Pulmonalia operculata, is composed
of individuals classed by Cuvier among the
Pectinibranchiata, to which in every cir-
cumstance, with the exception of the struc-
ture of the respiratory system, they are closely
allied ; these, however, breathe the air in a
cavity analogous to that which we have just
described, only differing in the position and
nature of the aperture leading to it, which here,
instead of being a rounded orifice in the margin
of the collar, opened and closed at the will of
the animal, is a large fissure placed above the
head, exactly as in the Pectinibranchiate order.

Organs of circulation. — Having thus de-
scribed the different arrangements of the
branchiae, we shall be enabled more readily
to investigate those modifications in the dis-
position of the organs subservient to the cir-
culation of the blood which are dependent
thereupon. Throughout the whole class, with

GASTEROPODA.
Fig. 190.

391

the exception of the Scutibrauchiate and some
of the Cyclobranchiate orders, the heart is
single, consisting of an auricular and ventri-
cular cavity, and is interposed between the
branchial or pulmonary vessels and the system,
receiving the aerated blood from the respiratory
organs, and propelling it through the body.
The heart of Aplysia (jig. 191, e, g) or of the
Snail, (Jig. 190, o, p) will exemplify its ordi-
nary structure. The auricle varies slightly in
shape in different genera, but is always ex-
tremely thin and pellucid, containing in its
coats muscular bands of great delicacy. The
ventricle is provided with stronger walls, and
is generally separated from the auricle by a
valve, formed of two pieces. The heart is en-
closed in a pericardium, but its position is re-
gulated by that of the branchiae ; and from the
great diversity of arrangement which we have
found the latter to present, a corresponding
want of uniformity in the locality which the
heart occupies may be readily expected. We
shall select two forms of the respiratory organ
as examples of the variable position of the
heart, and as illustrations of the usual distribu-
tion of the bloodvessels, viz. the Snail, (vide
CIRCULATION, Jig. 322, and the Doris, fg.
321,) and afterwards notice the principal aber-
rations from the ordinary disposition, fn the
Snail, the blood derived from the whole body
is brought by great veins, performing the func-

tions both of the vena cava and of a pulmonary
artery, to the plexus of vessels lining the floor
of the respiratory cavity ; after here undergoing
the needful aeration, it enters the heart, from
whence it is driven into the aorta. The aorta
immediately divides into two trunks, one dis-
tributed to the liver, the intestine, and the
ovary; the other supplying the stomach, the
oral apparatus, the organs of generation, and
the foot. In the Slug the arteries are perfectly
white and opaque, and their ramifications,
which may be traced with great readiness, are
extremely beautiful.

In Doris (Jig. 321) the heart is, in conse-
quence of the position of the branchiae around
the anus, removed quite to the posterior extre-
mity of the body. The blood derived from all
parts of the body is conducted by large veins
to the respiratory organs ; the pulmonary arte-
ries which return it from thence unite into a
circular vessel (6, 6), surrounding the anus,
and from this arise two vessels, emptying them-
selves into the auricle. The aorta, on issuing
from the heart, divides into two large vessels,
the first supplying the intestinal canal, stomach,
and duodenum, the organs of generation, the
foot, and the mouth; whilst the other large
trunk is entirely distributed to the liver.

In Tritonia the heart is placed near the
centre of the body, and the auricle itself resem-
bles a cylindrical vessel placed transversely

392

GASTEROPODA.

across the other riscera, and communicating
with the ventricle near its middle. The blood
arrives at the heart through four vessels from
the long fringe of branchiae, two coming from
the anterior and two from the posterior parts.
We have already described the disposition of
the branchiae in the Tectibranchiate order, but
in following the course of the circulating fluid,
we shall find in some of the individuals in-
cluded in this division circumstances requiring
special notice, as being of extreme interest to
th° physiologist. In Aplysia, the blood re-
tuiried from the system is brought by two large
ve~>HS trunks to the vena cava or pulmonary
artery (fig. 191, % for in this case the same

vessel performs the functions of both ; these
large veins turn round in the vicinity of the
operculum, and unite into one trunk prior to
their dispersion over the branchial plates, but
on opening them at this point so as to display
their interior, a most singular arrangement is
brought to light; the sides of the veins are found
to be formed of muscular bands (c) crossing each
other in various directions, and leaving spaces
between them ; these intervals are seen even
by the naked eye to be apertures establishing a
free communication between the interior of the
vein and the abdominal cavity, and allowing
injection to pass with facility from the vein
into the visceral cavity, or from the abdomen
into the vein : the anterior portion of each of
these vessels may indeed be said to be literally
confounded with the general cavity of the
the body, a few muscular bands, forming no
obstacle to a perfect communication, being the
only separation between the two. It is there-
fore evident that the fluids contained in the
abdominal cavity may in this manner have
free access to the mass of the blood as it
approaches the respiratory organ, and that the
veins can thus perform the office of the ab-
sorbent system ; but in what mariner the blood

is prevented from escaping through the same
channels is not at all obvious, although pro-
bably during life the contraction of the fasci-
culi which bound these apertures may in some
measure obstruct the intercourse. It is from
this circumstance, and the analogous commu-
nication which exists in the Cephalopoda by
the intervention of the spongy appendages to
the venae cavse found in those Mollusks, that
Cuvier was led to the conclusion that in all the
class the veins are the immediate agents of
absorption, and that an absorbent system does
not exist in any but the vertebrate division of
the animal kingdom. We meet, moreover,
in Aplysia with another peculiarity in the cir-
culating vessels; the aorta, shortly after its
commencement, divides into two large arteries
(h h'\ one of which presents nothing peculiar
in its distribution ; but to the larger of the two,
whilst still enclosed in the pericardium, we
find appended a remarkable structure, the use
of which has been hitherto perfectly inexpli-
cable : projecting from the opposite sides of
the vessel are two vascular crests, represented
in i, formed of a plexus of vessels issuing
from the aorta itself, and ramifying in an ex-
ceedingly beautiful manner through the sub-
stance of these extraordinary organs; in other
respects the arteries are distributed in the usual
manner. The Cyclobranchiate and Scutibran-
chiate Gasteropods approximate the testaceous
class in many points of their organization, but
in none more so than in the position which the
heart is found to occupy, and the arrangement
of its cavities. In Patella, indeed, the heart
is placed in the anterior part of the body, and
still conforms in its general structure to the
description which we have given above ; but
in Oscabrio the auricle is divided into two
distinct portions, one receiving the blood from
each range of branchial plates; and in Haliotis,
Fissurella, Emargenula, and Parmophorus, not
only is this division of the auricle met with,
but the ventricle, as in many of the testaceous
Mollusks, is perforated by the rectum, and
the similarity of arrangement which is here
presented with what is met with in the Con-
chifera will be readily appreciated by a refer-
ence to the article which treats of the anatomy
of that division of the Mollusca.

Nervous system. — The nervous system of
the Gasteropoda furnishes us with the most
perfect form of the heterogangliate, or as it has
been less happily denominated, cyclo-gangliated
type. It consists of a variable number of
ganglia or nervous centres disposed in different
parts of the body, but connected with each
other by cords of communication, and from
these ganglia the nerves appropriated to dif-
ferent parts proceed. Each ganglion,, therefore,
is a distinct brain; and were the preponderance
in size to be regarded as the criterion of rela-
tive importance, it would not unfrequently be
hard to say to which the pre-eminence is due.
There is, however, as we shall soon perceive,
an uniformity in the arrangement of certain
masses, and a regularity in the appropriation
of the nerves proceeding from them to parti-
cular organs, which leave us little room for

GASTEROPODA.

393

hesitation upon this point ; before, however,
entering upon a more detailed account, we
will offer a few general observations upon this
system, applicable to the whole class. The
nervous centres are obviously of a different
nature from the cords by means of which they
are connected into one system, and from the
nerves arising from them ; the nervous mass
of the ganglion itself is generally granular in
its appearance, whilst the texture of the nerves
is homogeneous and smooth ; the distinction
is, however, in a few instances, rendered still
more remarkable by a striking difference in
colour; thus in Aplysia, whilst the nerves are
of a pure white, the ganglionic centres are of
a beautiful red tint; the same circumstance is
met with in the Bulimus Stagna'is, and has
also been remarked in many of the conchi-
ferous Mollusca. A second peculiarity may
be noticed in the mode in which the nerves
and ganglia are invested with a neurilema or
sheath, so loosely connected with them that it
may be inflated or injected with great facility,
and for this reason the nerves have been mis-
taken for vessels by some authors.

As an example of the most perfectly dis-
persed arrangement of the nervous centres we
shall select Aplysia, in which the ganglia are
more numerous than in the generality of the
Gasteropod Mollusks. In this animal we find
a ganglion placed above the oesophagus to
which the name of the brain is universally
allowed, not so much on account of its size
as because throughout the class it constantly
occupies the same position, and as invariably
supplies those nerves which are distributed to
the most important organs of sense ; in this
case its branches run to the muscles of the
head and to the male organ of generation ; it
likewise sends on either side a large branch to
each of the great tentacles, which as they
approach those organs give origin to the optic
nerves.

On each side of the oesophagus is found
another ganglion equalling the brain in size,
and constituting two other nervous centres,
which are united to each other and to the brain
by cords so disposed as to form a collar around
the oesophagus; each of these gives off a
number of nervous filaments, which are lost
in the muscular envelope of the body ; a
fourth ganglion joined to the brain by two
cords is found under the fleshy mass of the
mouth ; this supplies the oesophagus, the
muscles of the mouth, and the salivary glands.
At a considerable distance from these, and
placed near the posterior portion of the body
in the vicinity of the female generative organs
and the respiratory apparatus, is a fifth gan-
glion communicating with the second and third
by means of two long nerves, and giving
branches to the liver, the alimentary canal,
the female generative system, as also to the
branchiae and the muscles of the operculum.
From this account it will be seen that none of
these ganglia can be said to preside exclusively
over any particular apparatus, branches from
each being distributed to very different struc-
tures ; but yet, speaking generally, there ap-

VOL. II.

pears to be some reason for classifying their
functions. Thus the brain is exclusively the
centre of the principal senses : the two great
lateral ganglia supply the bulk of the muscu-
lar system ; the sub-oral ganglion is particularly
subservient to mastication and deglutition, and
the fifth or posterior nucleus being almost
entirely appropriated to the supply of the
digestive, respiratory, circulatory, and gene-
rative viscera, might be regarded as analogous
to the sympathetic. There are, however, but
few of the Gasteropoda in which the ganglia
are so distinct in position and function as in
Aplysia. In the inoperculate pulmonary Gas-
teropods, as in the Snail and Slug, the nervous
centres are only two in number, namely, the
brain, placed in its usual position above the
oesophagus, and a large sub-oesophageal gan-
glion connected with it by two cords embracing
the oesophageal tube. The brain in this case
supplies nerves to the muscles of the mouth
and lips, as well as to the skin in their vici-
nity ; it likewise furnishes the nerves of touch
and of vision, besides those distributed to the
generative organs, and from the sub-oesopha-
geal ganglion, which fully equals the brain in
size, arise those nerves which supply the
muscles of the body and the viscera. There is,
however, placed under the oesophagus a very
minute nervous mass, which from the con-
stancy of its occurrence is worthy of notice ;
it is formed by the union of two minute nerves
arising from the brain, and the little filaments
which it gives off are lost in the oesophagus
itself.

One remarkable circumstance may be men-
tioned as being probably peculiar to the class
under consideration, namely, the changes of
position to which their nervous centres are
subject ; obeying the movements of the mass
of the mouth, with which they are inti-
mately connected, they are pulled backwards
and forwards by the muscles serving for the
protrusion and retraction of the oral appa-
ratus, and are thus constantly changing their
relations with the surrounding parts. In the
Snail it would seem that the great size of the
nervous collar which embraces the oesophagus
will in some circumstances permit the mass
of the mouth to pass entirely through it, so
that sometimes the brain rests upon the oeso-
phagus, and at others is placed upon the in-
verted lips.

In most of the Pectinibranchiata, the brain
consists of two ganglia united by a transverse
cord ; from these two centres arise the principal
nerves, two of which unite to form a small
ganglion beneath the oesophagus, from which
that tube derives its peculiar supply.

It is in the Nudibranchiate division, how-
ever, that the nervous centres exist in their
most concentrated form, and in these it is
doubtful whether there are any ganglia, except
the large supra-cesophageal brain. We may
take Tritonia as an example of this form of the
nervous system. In this beautiful Gasteropod
the brain consists of four tubercles placed
across the commencement of the oesophagus,
the nervous collar being completed by a simple

2 D

394

GASTEROPODA.

cord; all the nerves which supply the skin,
the muscular integument, the tentacles, the
eye, and the muscles of the mouth arise from
the brain, and anatomists have not hitherto
detected any other source of nervous supply,
although Cuvier suspected two minute bodies,
which he found beneath the oesophagus appa-
rently connected with the brain, to be of a
ganglion ic nature.

The slow-moving and repent tribes of which
we are now speaking have their powers of sense
almost entirely limited to the perception of
objects in actual contact with their bodies,
and instruments adapted to touch and vision
are the only organs of sense which the anato-
mist has been able to distinguish. The utter
want of an internal skeleton or of an external ar-
ticulated crust forbids us to expect that any of
them are provided with an apparatus specially
calculated to appreciate sonorous undulations.
Their tongue, coated as it is with horny plates,
studded with spines, or absolutely corneous in
texture, is obviously rather an instrument of
deglutition than an organ of taste. No re-
searches have hitherto detected any part of the
body which could be looked upon as devoted
to smell ; the eye is generally a mere point,
rather inferred to be such by analogy than
clearly adapted to vision; and the sense of
touch in fact is the only one which anatomical
evidence would intimate to be perfectly deve-
loped. Yet in spite of these apparent defi-
ciencies, observation teaches us that many genera
are not utterly deprived of the power of appre-
ciating intimations from without connected with
the perception of odours ; it has been found
by direct experiment that some of them are pe-
culiarly sensible of the approach of scented
bodies ; thus the snail, although at rest within
the shelly covering which forms its habitation,
will with great quickness perceive the proximity
of scented plants which are agreeable articles of
food, and promptly issue from its concealment
to devour them. Some anatomists have sup-
posed that it is at the entrance of the respiratory
cavity that we are to look for the special seat of
smell, where, as the air alternately enters and is
expelled by the movements of respiration, the
odorous particles with which it may be impreg-
nated are rendered sensible. Others with
scarcely less probability conceive that the whole
surface of the body which is exposed to the at-
mosphere may be endowed with a power of
smelling, the quantity of nerves which are dis-
tributed to the integument, and the moisture
with which it is constantly lubricated, seeming
to adapt it perfectly to the performance of this
function, giving it all the characters of a
Schneiderian membrane. It is not impossible
that sounds may be perceived in a somewhat
analogous manner, although no proof has yet
been adduced that any of the Gasteropoda are
sensible to impressions of this nature. The
sense of touch is exquisitely delicate over the
whole surface of the animal, but more especially
so in the foot, which is extremely vascular and
abundantly supplied with nerves ; yet in spite
of this delicacy in the organisation of the skin
which makes it so sensible of contact, it appears

to have been beneficently ordered that animals
so helpless and exposed to injury from every
quarter, are but little sensible to pain, and that
such is the case, M. Ferussac, a diligent ob-
server of their economy, bears ample testimony.
" I have seen," says he, " the terrestrial gaste-
ropods allow their skin to be eaten by others,
and in spite of large wounds thus produced,
shew no sign of pain." But besides the sen-
sation generally distributed over the skin, we
may observe in most instances organs of variable
form which seem peculiarly appropriated to
touch. These are the tentacles, or horns as
they are usually termed, which occupy a va-
riable position upon the anterior part of the
animal.

The tentacles vary in number in different
genera : thus in Planorbis we find two, in the
generality of cases four ; in a few, as some spe-
cies of (Eolis, six; and in Polycera even eight of
these appendages are met with. The structure
of the tentacles is by no means the same in all
the individuals belonging to this class. In the
aquatic species they are to a greater or less ex-
tent retractile, but can in no case be entirely
concealed within the body, as is usual in the
terrestrial division ; they are therefore not hol-
low, but composed of various strata of circular,
oblique, and longitudinal muscular fibres, by
means of which they are moved in every direc-
tion, and applied with facility to the objects
submitted to their examination. In all instances
they are plentifully supplied with nerves
arising immediately from the brain. Their
shape is subject to great variation ; they are
usually simple processes from the surface of the
body more or less elongated, and in some cases
even filiform, as in Planorbis. In Murex
(Jig. 193) each tentacle is a thick and fleshy
stem, near the extremity of which a smaller one
is appended. In Tritonia each tentacle is com-
posed of five feathery leaflets, and is enclosed
in a kind of sheath which surrounds its base.
In Doris the two inferior are broad, flat, and
fleshy, while the superior are thick and club-
shaped. In Scyllcea they consist of broad
fleshy expansions attached by thin pedicles to
the anterior part of the body. In Thethys
they are placed at the base of the veil which
characterises the animal, but in all cases they
are solid and incapable of entire retraction. In
the terrestrial Gasteropoda, in which from many
causes the tentacles are more exposed to injury,
a much more complicated structure is needed,
by which these important organs are not only
moved with facility in different directions, but
which allows them to be perfectly withdrawn
into the interior of the body, from which posi-
tion they may be made to emerge at the will of
the animal : the mechanism by which this is
effected will be understood by referring to^g.
192, representing a dissection of the common
snail, and exhibiting the tentacles in different
states of protrusion. Each tentacle (c, d,) is here
seen to be a hollow tube, the walls of which are
composed of circular bands of muscle, and
capable of being inverted like the finger of a
glove; it is in fact, when not in use, drawn with-
in itself by an extremely simple arrangement,

GASTEROPODA.

395

Fig. 192.

Structure of the tentacles in the Garden- Snail
(Hel'uc Pomatia).

From the common retractor muscles of the
foot four long muscular slips are detached,
one for each horn ; these run in company with
the nerve to each tentacle, passing within its
tube when protruded, quite to the extremity
(g)- The contraction of this muscle dragging
the apex of the organ inwards, as seen at c, of
course causes its complete inversion, whilst its
protrusion is effected by the alternate contrac-
tions of the circular bands of muscle of which
the walls of each tentacle are composed. There
is, however, another peculiarity rendered neces-
sary by this singular mechanism, by which the
nerves supplying the sense of touch may be
enabled to accommodate themselves to such
sudden and extensive changes of position ; for
this purpose the nerves supplying these organs
are of great length, reaching with facility to the
end of the tubes when protruded, and in their
retracted state the nerves are seen folded up
within the body in large convolutions. In the
figure, a a indicates the origins of the retractor
muscles of the foot from the columella; b, the
right superior tentacle fully protruded ; c, the
left superior tentacle partially retracted ; d, the
left inferior tentacle extended, and e, the right
inferior tentacle fully retracted and concealed
within the body ; J\ the nerve supplying the
superior tentacle elongated by its extension ;
g, the retractor muscle of the same tentacle
arising from the common retractor muscle of
the foot and inserted into the extremity of the
tube ; h, the nerve of the opposite side thrown
into folds ; i, the retractor muscle of the same
tentacle contracted ; k, the aperture through
which the nerve and retractor muscle enter the
tentacle d ; I, the brain ; m, the subcesophageal
ganglion ; n, the eye.

Vision. — The eyes of Gasteropoda are ex-
tremely small in comparison with the bulk of
the animals, and seem more to represent the
rudiments of an organ of sight than to be
adapted to distinct vision. In many species
indeed they appear to be absolutely wanting.
When found, they resemble minute black points,

by far too small to admit of any satisfactory
examination of their internal structure; and even
in the largest forms of the organ which are met
with in the more bulky marine genera, it is with
difficulty that their organisation can be explored.
In Jig. 193 we have delineated the position
and structure of the eye in a large Murex.
Fig. 193.

Tentacles and eye of Murex.

The natural size of the organ is seen in the
upper figure, in which on the right side the organ
is represented untouched, while on the left a
section has been made to exhibit its interior.
This section when magnified, as in the lower
figure, shews us that it consists of a spherical
cavity lined posteriorly with a dark choroidal
membrane, and containing a large spherical lens;
the position and structure of the retina we have
been unable satisfactorily to determine, although
the visual nerve may be readily traced to the
back of the choroid, where it seems to expand ;
but whether, as in the Cephalopods, its sentient
portion is spread out behind the pigment
which lines the eye-ball, or whether, as in the
forms of the organ common to the vertebrate
orders, the retina is placed anterior to the
choroid, is a question which we are at present
unable to solve. But however this may be, we
see anteriorly a distinct pupil surrounded by a
dark radiating zone, apparently an iris, to which
it corresponds at least in position, although
that it is really capable of contracting or en-
larging the pupillary aperture is more than our
observations warrant us in affirming. Finding,
therefore, the eye of the Murex to offer a struc-
ture which indubitably entitles it to be regarded
as an organ of sight, we are justified in consi-
dering the more minute specks of smaller Gas-
teropoda as similarly formed and subservient to
the same office. In the aquatic species the
eyes are generally placed at the base of the su-
perior or larger tentacles, although not unfre-
quently they are supported upon short pedicles
appropriated to them, as is the case in Huliotis
and others. In Murex we have seen that the
tentacles which support them are large and
2 D 2

396

GASTEROPODA.

fleshy, and by the position of the eyes at the
extremity of so long a stem these can be readily
directed to different objects. In no case, how-
ever, can they be retracted within the body so
as to be quite enclosed in the visceral cavity. In
the terrestrial Gasteropods the eyes are gene-
rally placed at the extremity of the superior
horns, a position which manifestly extends the
range of vision, and moreover, in consequence
of the structure which we have described when
speaking of the organs of touch, may be com-
pletely drawn within the body. In Jig. 189, 6,
the eye of Vaginulus is seen at the extremity of
the upper tentacle, and the origin of the optic
nerve (c) from the brain (d), as well as the
convolutions which it makes to allow of its
adaptation to the varying length of the tentacle,
and the bulb in which it terminates behind the
eyeball (b*),a.re sufficiently displayed. ~Lnjig.
192, 6, the eye of the snail exhibiting the same
circumstances has been represented, and the
apparatus by which the movements of the whole
organ are effected is so clearly shewn as to
render further description superfluous.

Generative system. — The description of the
generative apparatus of the Gasteropoda forms
one of the most remarkable parts of their
history, and the complication which it presents
in some orders is probably unique in the ani-
mal kingdom. The class may be divided, as
far as relates to this function, into three great
divisions: — 1st. Hermaphrodite and self-im-
pregnating ; 2d. Hermaphrodite, but recipro-
cally impregnating each other by mutual
copulation ; 3d. Sexes distinct, the female
being impregnated by copulation with the
male. We shall consider each of these divi-
sions in the order in which they have been
enumerated. The lowest orders approximate
the Conchifera in most parts of their organisa-
tion, and in the arrangement of their generative
system we need not be surprised to see a
manifest resemblance. The Scutibranchiate
and Cydobranchiute orders, therefore, present
this great distinguishing character, which more
than any other detaches them from the others,
namely, that every individual being furnished
both with ovigerous and impregnating organs
is sufficient to the impregnation of its own
ova. Nothing, in truth, can be more simple
than such an arrangement. The ovary is found,
•when empty, embedded in the substance of
the liver, but at certain epochs it becomes so
much distended with ova as to cover in great
part the rest of the viscera ; from this ovary
arises a simple canal or oviduct, which termi-
nates after a short course in the neighbourhood
of the anus. No trace of accessory apparatus
has been found, and the only part to which
the office of a testis is assignable is the tube
through which the ova are discharged, which
probably furnishes a secretion subservient to
the impregnation of the eggs. Such is the
structure of the generative system in Haliotis,
Patella, and others of the orders to which
these respectively belong, exhibiting a simpli-
city of parts widely different from what is
found in the division which next presents itself
to our notice. The second type of the genera-

tive apparatus is common to the Nudibran-
chiate, Infer abranchiate, Tectibranchiate, and
Inoperculated pulmonary orders; in all of which
every individual is provided with both male and
female organs of copulation, and, accordingly,
mutual impregnation is effected by the congress
of two individuals, or in a few instances by
the combination of several. We shall select
the common snail ( Helix pomatia ) as the most
familiar illustration of the general arrangement
of the parts composing this double apparatus,
leaving the varieties which it presents to sub-
sequent notice. The admirable plate of Cuvier,
of which fig. 190 is a copy, represents the
whole system with that clearness and fidelity
so characteristic of all the laborious contribu-
tions to science which we owe to his indefati-
gable industry. The female portion consists
of the ovary, the oviduct, and an enlarged
portion of the oviduct which forms a receptacle
for the ova, and is called by Cuvier the womb
(la ma trice). The ovary (q) is a racemose
mass embedded in that portion of the liver
which is enclosed in the last spire of the body,
i. e. that part which is placed nearest to the
apex of the shell ; from this proceeds a slender
oviduct (r), folded in zigzag curves, and vari-
ously convoluted : it commences by many
small branches derived from the ovary, and
terminates in a mass (*), regarded by Cuvier
as the testis, in which it becomes so attenuated
that it is difficult to trace it ; emerging, how-
ever, from this mass, it expands into the
womb (£), which is a long, capacious, and
sacculated canal, and capable of much dis-
tension, in which the eggs are retained until
they have acquired their full development :
this viscus opens into the common generative
cavity at e, Jig. 194.

The male organs consist of a testicle, vas
deferens, and penis. The testicle (s,Jig. 190)
appears to be composed of two distinct portions,
the larger of which is soft and homogeneous in
texture, but the smaller has a granulated ap-
pearance ; the latter (M) runs along the womb
like a mesentery, connecting its folds as far as
the termination of that viscus. The testicle
varies much in size at different periods, being
generally very small, but during the season of
love it dilates so as to fill nearly half of the
visceral cavity, at which time the womb like-
wise is much enlarged. From the testicle
arises its vas deferens or excretory duct, which
terminates in the penis near the base of that
organ. The penis (fig. 194, n) is a most sin-
gular instrument, resembling a long hollow
whip-lash, formed of circular fibres, and, like
the tentacles, capable of complete inversion,
which in fact occurs whenever it is protruded
from the body ; it is also furnished with a re-
tractor muscle (Jig. 190, w), serving to draw it
back again after copulation is accomplished.
The penis is not perforated at its extremity,
but the vas deferens terminates within it by a
small aperture, which of course during the
inversion of the organ opens externally at
about one-third of the length of the penis from
its root ; the aperture by which the vas defe-
rens thus opens upon the exterior of the penis,

GASTEROPODA.

397

when that organ is protruded, is sufficiently
distinct, admitting with facility an ordinary
bristle (^/zg.194, I). On slitting up the penis
as it usually lies retracted into the visceral
cavity, its inner membrane is found gathered
into longitudinal folds, and this provision is
needful to allow of that distension which must
occur during its erection, at which time this
lining membrane becomes the external integu-
ment of the protruded organ.

These parts would seem sufficient in them-
selves to fulfil the functions belonging to the
organs of both sexes, nevertheless we find
others superadded, the uses of which are not
so readily assignable; these are the bladder,
as it is called by Cuvier, the multifid vesicles,
and the sac of the dart.

The sac ^Ahich has been called the bladder
(fig- 190, z, Jig. 194, o) is invariably present;
it consists of a round vesicle, variable in size,
communicating by means of a canal, generally
of considerable length and diameter, with the
termination of the matrix : it is usually found
filled with a thick and viscid brownish matter,
and is generally supposed to furnish an enve-
lope to the eggs as they escape from the con-
voluted oviduct, an opinion, however, as we
shall afterwards see, which is not without op-
ponents.

The multifid vesicles (fig. 190, x, fig. 194,
c) are much less constantly met with, and are
in fact almost peculiar to the snail ; they are
two groups of cceca, each composed of about
thirty blind tubes, which after uniting into
larger canals ultimately form a principal duct
on each side, through which the secretion
which they furnish is poured at a little distance
below the orifice leading to the bladder into
the passage by which the ova are expelled.
The fluid furnished by these curious glandular
appendages is white and milky, but as this
secretion is almost peculiar to the genus Helir,
its use is extremely problematic.

The sac of the dart (Jig. 190, y, fig. 194, b)
is another part of the generative apparatus only
found in the snail, and from the extraordinary
instrument which it conceals is perhaps the
most singular appendage to the generative sys-
tem met with in any class of animals. It is
an oblong sac with strong muscular walls
opening by a special aperture into the common
generative cavity, like which it is capable of
complete inversion. On opening it, its cavity
is seen to be quadrangular, and at its bottom
projects a four-sided fleshy tubercle, which
secretes the curious weapon that this sac is
destined to conceal. This (fig. 194, b) con-
sists of a four-sided calcareous and apparently
crystalline spike, about five lines in length,
which grows by successive layers deposited at
its base from the surface of the fleshy tubercle
to which it is attached : it will be evident that
when the sac is everted, the dart contained
within it will be protruded externally. This
dart, if broken off from its place of attachment,
is speedily renewed.

To complete our description of the parts
composing this complex organisation, it remains
only to mention the common generative cavity

Fig. 194.

Generative organs of Helix Pomatia.

(Jig. 194, a), into which the others open; this,
when in its ordinary position, is a muscular
bag, opening externally by a large aperture
near the upper tentacle on the right side of the
neck, whilst at its bottom are seen the orifices
of three distinct passages, one leading to the
penis, one to the female organs, and a third
to the sac of the dart. This cavity, like that
of the dart, is capable of inversion, which is
effected partly by the action of its muscular
walls, aided in all probability by a kind of
temporary erection, and when thus turned in-
side out, the orifices leading to the penis, the
womb, and the sac of the dart of course
become external.

In order to understand the functions of these
various parts it will be necessary to describe at
length the singular mode hi which copulation
is effected. When two snails, amorously dis-
posed, approach each other, they begin their
blandishments by rubbing the surfaces of their
bodies together, touching successively every
part. This preliminary testimony of affection
lasts for several hours, gradually exciting the
animals to more effective demonstrations. At
the end of this time the generative orifice,
placed on the right side of the neck, is
seen to dilate, and the common generative
cavity becoming gradually inverted displays ex-
ternally the three apertures which open into it.
This being effected, an encounter of a truly
unique character commences; the opening
leading to the sac of the dart next expands,
and that organ undergoing a similar inversion
displays the dart affixed to its bottom. A
series of manoeuvres may then be witnessed of
an unaccountable description ; each snail, in
turn, inspired with an alacrity perfectly foreign
to its ordinary sluggish movements, striving
with his dart to prick the body of his associate,
which with equal promptitude endeavours to

398

GASTEROPODA.

avoid the wound, retreating into his shell, and
performing a variety of evolutions to get out of
reach. At length, however, the assailant suc-
ceeds, and strikes the point of his weapon
into the skin of his paramour at any vulnerable
point which may be found. The dart is gene-
rally broken off by this encounter, sometimes
sticking in the skin, but more frequently
dropping to the ground. The reptile Cupid
having thus exhausted his quiver, becomes in
turn the object of a similar attack, exhibiting
apparently an equal anxiety to avoid the threat-

ening point of the weapon bared against him.
At last he receives the love-inspiring wound,
and the preliminaries thus completed, each
prepares for the completion of their embraces.
The other two apertures next dilate, and from
one of them issues the long and whip-like penis,
unrolling itself like the finger of a glove ; this
being fully developed is introduced into the
vaginal orifice of the other snail, which in the
same manner inserting its penis into the female
aperture of the former, both mutually impreg-
nate and are impregnated. See jig' 195.

Fig. 195.

It is difficult to conceive what can be the
use of the dart so singularly employed; it
would seem to be an instrument for stimulating
the sleeping energies of the creatures to a
needful pitch of excitement ; yet why it should
be peculiar to the snail is not obvious, for in
the slug and other Mollusca certainly not less
apathetic, no such structure has been detected.

In Vaginulus (fig' 189) a similar arrange-
ment of the principal organs is observable,
although some modifications are met with
which deserve our notice. No sac of the dart
is found in this animal, but a fasciculus of
cceca, analogous to the multifid vesicles as far
as their structure is concerned, is connected,
not with the female apparatus, as in the snail,
but with the male organs. The orifices of the
two sexual systems are here separated by a
considerable interval, the penis emerging at
the side of the neck, near the right superior
tentacle at z, while the orifice of the female
parts is placed between the cuirass and the
mantle, considerably further back. The ovary
(ni) is similar in structure to that of the snail ;
and its duct, in like manner, forms many
convolutions in the substance of the testicle
(p), from which it issues, much increased in
size, to expand into a large membranous re-
ceptacle (<?), corresponding in function with
the tortuous matrix of the Helices; this part
of the oviduct is filled with an albuminous
fluid, and from it runs the narrower canal (r),
which may be regarded as the vagina, and
which before its termination communicates
with a lateral pouch, identical with what has
been called the bladder. The testicle (p) ap-
pears to consist of two portions, from which

arises the vas deferens (o). On tracing this
tube it is seen to divide into two branches, one
opening into the bladder (s), an arrangement
to which we shall again have occasion to revert,
whilst the other runs fonvard to the root of the
penis (w). The latter organ presents two por-
tions, a long tubular coecum (u), resembling
the corresponding part in the snail, and a
thick muscular cavity, from which the former
arises as a kind of appendage ; on opening the
thicker portion its interior is seen to be rugose,
and to enclose a small body, something like
the caput gallinaginis in the human urethra.
The multijid vesicles (j/) open near the exterior
orifice, through which the whole apparatus, by
a process of inversion already described, is
protruded so as to form the male organ of ex-
citement.

In many of the Tectibranchiata a remark-
able arrangement of the generative organs is
found, as the male viscera are divided into two
distinct portions, the exciting organ being at
one extremity of the body, while the testis is
found connected with the female apparatus in
a distant part of the system. This will be
seen in Doridium Meckelii (Jig- 196); the
penis (/), seen retracted in the figure, issues
from the side of the neck, and has appended
to its root a zig-zag tube, inclosed in a mem-
branous canal, the nature of which is un-
known. Quite detached from these, and
placed near the anus, we have the matrix (f)9
the testis (g), and the bladder (i), occupying
their usual relative position as regards each
other, and terminating in the vulva or sac of
generation (//).

In Aplysia the organ of excitement is found

GASTEROPODA.

399

Fig. 196.

near the right tentacle, where it protrudes, as
in the Snail, for the purpose of copulation,
by the inversion of its walls ; it is, however,
absolutely imperforate, and receives no duct
by which it can communicate with the testis
so as to become instrumental in immission;
but externally a deep groove is seen upon its
surface when in a state of protrusion, which is
continuous with a long furrow seen upon the
surface of the body, continued from the base
of the penis to the orifice of the female ap-
paratus. Fig. 197 represents the secreting

Fig. 197.

portions of this system removed from the body,
and displayed so as to expose the internal
structure of the parts composing it. The
ovary (h) is a large oval, whitish, and granular
mass, from which the oviduct arises by several
distinct tubes which emerge from different
parts of its substance : this oviduct opens into
the common tube (e\ which may be called the
vagina. The mass (f,g\ called by Cuvier
the testis, and supposed by him to be solid
and homogeneous in its texture, is found, when
opened, to be divided by spiral septa, resem-
bling the scala cochleae in the ears of Mam-
malia (g), and thus forms a long spiral cavity
communicating with the commencement of the
vagina, in which latter tube we also find aper-
tures by which the vesicle (p) and the larger
sacculus (o) communicate with the common
passage.

In Onchidium, an aquatic species belonging
to the inoperculate pulmonary order, the male
and female parts are in a similar manner
placed at opposite extremities of the body,
but the former assume a more complicated
structure than in the Tectibranchiata, which
we have described. The ovary (Jig. 198, A, a, a)

Fig. 198.

Generative organs of Aplysia.

Generative organs of Onchidium,

consists of two masses replete with ova, each
of which furnishes a short duct ; the two thus
formed unite into a convoluted tube (6), which
is the common oviduct : arriving at the mass
always regarded by Cuvier as the testis, it
enlarges and forms within the substance of
that organ many convolutions, on emerging
from which it runs directly in the shape of a
narrow canal (d), to the external orifice (h).
The bladder (f) receives a large duct (e) from
the mass here assumed to be the testis, and
gives off another of equal size, which joins the
oviduct (d) prior to its termination. This

400

GASTEROPODA.

would seem to form a complete system in
itself; yet, on examining the male organ
of excitement, we find it connected with
considerable appendages, the nature of
which it is difficult to conjecture. The sac
(w) is muscular, and resembles the mus-
cular root of the penis in the genera already
described, being, as in them, capable of in-
version : at its base are seen two cul-de-sacs,
into each of which opens a long and flexuous
canal (/, n). The canal marked n is very
slender, and when unfolded is four times the
length of the body of the animal ; its termi-
nation at the point most remote from the mus-
cular sac into which it opens is apparently
closed. The other tube marked / is much
wider and of extraordinary length; its com-
mencement (i) is extremely convoluted and fully
eight times as long as the body ; its walls are
thin, but it is supplied plentifully with blood
by means of a large artery interlaced with its
convolutions ; at k it becomes enveloped in a
fleshy mass of considerable thickness, after
which, assuming its original appearance, it
proceeds to the cul-de-sac, at the bottom of
which it terminates. In/g. B, 1 98, the muscular
cavity (m} has been laid open, and the mode
in which the above tubes enter it has been
displayed ; the smaller one (n) ends in a little
horny papilla (9) seen in the engraving ; the
larger tube (/) terminates by a kind of glans
penis, perforated by a large aperture and sur-
rounded by a kind of prepuce (p) : on open-
ing the vessel a little before its entrance into
the muscular sac, it is found to conceal a
sharp horny dart (o), supported upon a fleshy
pedicle, and readily protrusible through the
aperture p; the analogy between this singular
instrument and the dart of the Snail is ob-
vious, for when the muscular sac (/«) is
everted, the papillae (p, q) become external,
and the horny point being pushed out of the
former will probably form a stimulus of the
same description.

We have hitherto abstained entirely from
mixing up with our description of these prin-
cipal forms which the generative system of the
mutually impregnating Gasteropoda presents,
the discussions which have arisen concerning
the real nature of the different organs which
have been described, and have designated them
by the terms usually applied to the respective
parts,without reference to their individual func-
tions. It now, however, becomes necessary
to lay before our readers the principal opinions
which are recorded upon this subject. The chief
points of debate have been the bladder, and
the organ which we have described under the
appellation of testicle. The bladder is, from
its constant occurrence, evidently an organ of
some essential use : it was regarded by
Swammerdam as the secreting structure from
which the colouring fluid peculiar to some
species is produced, especially in the Murices
and others of the marine genera ; it was there-
fore named by him sac of the purple; but we
shall afterwards find that this fluid is derived
from another source. Blainville, on the other

hand, considers this vesicle as analogous to the
urinary bladder of Vertebrata ; in reference to
this hypothesis, however, we should be inclined
to ask, with Cuvier, where are the kidneys ? and
even upon the supposition that the secretion of
the bladder itself was analogous to the urinary
fluid, we are not aware of any chemical proofs
of its nature which are sufficient to establish
the identity. Delle Chiaje again sustains that
the sac of the purple is, in fact, the testis, and
that its secretion, poured as it constantly is
into the termination of the oviduct, is in re-
ality the fecundating fluid ; yet against this we
must urge the distribution of the vas deferens
met with in the Helices, which from its entire
arrangement converts the organ of excitement
in these animals into an apparatus of immis-
sion, whose nature cannot be mistaken. The
opinion which we consider most consonant
with all the circumstances of its position, is
that it is a reservoir for the seminal fluid
analogous to the spermotheca of certain insects.
Cuvier expressly notices the constant relation
which exists between the length of the penis
and that of the canal which leads to this sac-
culus, and when we remark the long chains of
ova which are slowly extruded in most of the
Gasteropoda, we are readily disposed to admit
of the necessity of such a reservoir, which,
treasuring up the semen until the eggs are
about to be expelled, applies it efficiently to
the ova as they successively pass the orifice of
its duct. This supposition derives additional
weight from what we have found to be the
arrangement of the seminal ducts in Vaginulus
and Onchidium. In the former we observed
that, besides the canal, which, as in the Snail,
perforates the root of the penis arid thus be-
comes subservient to copulation, the vas de-
ferens actually pours a part of its contents by
a separate canal into the bladder itself, which,
as in all cases, communicates with the egg-
passage. In Onchidium the connexion be-
tween the testis and this receptacle is equally
striking, as will be obvious on reference to the
drawing given above. In Aplysia, Delle Chiaje
considers the testicle as described by Cuvier
to be in reality the matrix or receptacle for the
ova, in which they attain their full development
prior to expulsion, basing his opinion upon
the disposition of the spiral cavity which it
contains.

We are entirely left to conjecture as to the
uses of the other appendages found in par-
ticular species, and the multifid vesicles of the
Snail, which are wanting even in the Slug, the
tortuous canal connected with the penis of
Doridium, and the still more singular organs
belonging to the male apparatus of Onchidium,
must still remain the subjects of observation
and experiment.

The third form of the generative system in
which the sexes are distinct, is met with in
all the Pectinibranchiate order, and in the
operculated Pulmonalia of Ferussac. In Buc-
cinum, which we shall select as an example
of the general arrangement of the sexual organs
in the former, the male is at once distinguish-

GASTEROPODA.

401

Fig. 199.

Mule organs of Buccinum.

able by the enormous penis attached to the
right side of the neck (jig. 199), which is not,
as in the last division, capable of retraction
within the body, but remains permanently ex-
ternal, being, when not in use, folded back and
lodged within the branchial cavity, from which
however it is frequently protruded without any
apparent object.

In the female there is no rudiment of such
a structure, but the generative aperture is seen
to be situated a little within the edge of the
pulmonary cavity, being a simple hole leading
to the oviduct. The internal organs of the
male, represented in the annexed figure, con-
sist simply of a testicle and its excretory canal.
The testis is of considerable size, sharing with
the liver the smaller convolutions of the shell ;
from this arises the vas deferens, which forms
by its convolutions a kind of epididymis
(jig. 199, 6), and then increasing in diameter
enters the root of the penis, through which it
passes by a tortuous course (d) to the tubercle at
the extremity of this organ, where it opens
externally. The penis when opened, as re-
presented in the engraving, is seen to contain
strong transverse fasciculi of muscle, which
probably cause the erection of this organ ; they
will at the same time lengthen it, so as to
destroy in a great measure the zig-zag turns
into which the vas deferens is thrown in its
usual relaxed state.

In the female the position of the testicle is
occupied by the ovary, while the vas deferens
is represented by a thick and glandular oviduct.

In Murex the penis of the male is pro-
portionally smaller ; and, instead of a com-
plete vas deferens, penetrating to its extremity,
there is merely a groove along its surface, along
which the semen flows. In Valuta the ex-
terior groove only runs to the base of the penis,
and in Strombus the male organ is a mere
tubercle.

In the Pulmonalia operculata the organs of
both sexes are in every respect similar to those
of the Pectinibranchiate order. In Paludina
alone (Helix vivipara, Lin.) the penis is retrac-

tile,issuingfrom ahole found in the right tentacle,
and from the disparity in size between the
tentacles, arising from this cause, the male is
readily distinguished. The females of this
genus are not unfrequently ovo-viviparous,
the ova remaining in their capacious oviduct
until they are hatched.

Spallanzani asserts that, if the young of
Paludina are taken at the moment of their
birth, and kept entirely separate from others of
their species, they can reproduce without im-
pregnation, like the Aphides and Monoculi,
in which the same connexion with the male
is found to fecundate not only the female
herself, but her offspring for several generations.
Nevertheless, whether Spallanzani's observa-
tions be correct or not, the males are fully as
numerous as the females, so that it would be
difficult to imagine the object of such a de-
viation from the ordinary proceedings of na-
ture.

Ova. — The spawn of the Gasteropod Mol-
lusca is found under diverse forms ; it is
usually in the marine species attached to the
surface of stones, shells, or sea-weed, the ova
being connected with each other in long ri-
bands or delicate festoons, which are some-
times extremely beautiful and curious. The
Doris and Tritonia deposit their ova in this
manner, and the mass of eggs deposited by
them resembles a frill of lace of extreme
beauty. In Aplysia the spawn is found to
resemble long gelatinous threads, in the centre
of which the ova are seen, varying in tint, so
as to give different colours to different parts of
the thread; the whole strikingly resembles
strings of vermicelli, and the Italians in fact
have applied to them the name of vermicelli
marini. In Helix and Bulimus the eggs are
naked and protected by a hard shell, whilst in
Buccinum, Voluta, Murex, and other marine
species, the ova are enveloped in membranous
sacs agglomerated together in large bunches ;
these sacs have been erroneously regarded as
the eggs themselves; they are, however, merely
coriaceous envelopes, answering the purpose
of the gelatinous coating enclosing the eggs of
other species, several eggs being contained in
each bag, in which, when mature, the young are
easily seen. It would seem that extraordinary
provisions have been made by nature for the
multiplication of these creatures, in spite of
the numerous enemies which devour them, or
the vicissitudes of temperature to which, espe-
cially in the terrestrial species, their eggs are
necessarily subject. We are indebted to M.
Leuchs for several interesting observations
concerning the ova of slugs, which explain in
a great degree the quantities of them \vhich in
some seasons infest gardens and vineyards,
becoming, from the devastation which they
cause, serious plagues to the agriculturist.
The number of eggs varies with the healthiness
of the animal, the supply* of food, or the tem-
perature of the season ; yet it is probable
that a single slug will lay five hundred, under
ordinary circumstances: thus, supposing a
thousand of these creatures to be collected in

402

GASTEROPODA.

a given space, they will give birth in a few
weeks to five hundred thousand young slugs,
which multiplying in their turn would pro-
duce at the second laying two hundred and
fifty millions of eggs. This fact is well worth
the notice of the farmer, who, instead of dri-
ving away with so much assiduity crows and
other birds which live upon these destructive,
though apparently insignificant, animals, would
do well occasionally to cherish them as fellow-
labourers in his grounds. The Terrestrial Mol-
lusca, helpless and incapable of defence,
afford food to numberless indefatigable assail-
ants, and their preservation is provided for,
not only by the number of their eggs, but by
a peculiar tenacity of vitality which these ex-
hibit under circumstances which would be
thought sufficient to destroy the young before
they were hatched. The skin of the eggs of
the slug is coriaceous and very elastic, so that
when compressed they soon resume their
shape : exposure to intense cold does not de-
stroy their fertility, and they have been known
to resist a temperature of 40° without ap-
parent injury. When dried by artificial heat,
they shrivel up to minute points only distin-
guishable by the microscope, yet in this state,
if they be put into water, they readily absorb it
and are restored to their former plumpness.
The same thing happens to those which are
dried by the action of the sun and apparently
destroyed; a shower of rain is sufficient to
supply them with the fluid which they had lost
and to restore their fertility. This drying ap-
pears not to injure them. M. Leuchs found
that after being eight times treated in this
manner, they were hatched on being placed in
favourable circumstances, and even eggs in
which the embryo was distinctly formed, sur-
vived such treatment without damage.

Reproduction of lost parts. — Not less won-
derful is the power which snails possess of repro-
ducing lost parts, after mutilation by accident
or design. The results of the experiments of
Spallanzani upon this subject are very curious ;
he found that if the large tentacle of a snail
were amputated, the extremity of the stump
heals, forming a small swelling of a lighter
colour than the rest of the horn ; in this swel-
ling a black point soon becomes visible, which
is a new eye, and the mutilated member, in-
creasing in length, shortly equals its original
size, although it is for some time of a lighter
colour than its uninjured fellow, which in other
respects it perfectly resembles. The process
sometimes varies a little; it frequently happens
that the end of the stump, instead of becom-
ing round, is elongated and tapers to a point,
from the apex of which the new eye is seen to
" squeeze out ;" the end of the tentacle then
assumes a globular shape, and the most accu-
rate dissection cannot distinguish the newly
formed eye from the original. If, instead of
the horn, the head is cut quite off, a new one
will succeed : the new head, however, does not
at first contain all the parts of the old one,
but they are gradually developed, piece by
piece, at different intervals, until at length a

head differing little, if at all, from the original
pattern is completed. In some cases the ob-
ject is effected by a different proceeding, the
new part appearing like a round tubercle, con-
taining the rudiments of the lips and of the
smaller horns, which is united to the mouth
and the new-formed tooth, the other parts,
as the larger horns and the anterior part of the
foot, being totally deficient. In another snail
the larger tentacle on the right side first ap-
peared, not more than one-tenth of an inch
in length, but already provided with its eye,
and at a short distance beneath this the linea-
ments of the lips separately developed them-
selves. In a third snail a group of three horns
is seen, two of which will acquire their full
developement, while the third is just above the
level of the skin. These and many other
varieties have been observed; but in most
instances there is no perceptible difference
between the new head and the one cut off,
the exact line of separation being indicated
by an ash-coloured mark distinguishable two
years after the experiment. The same effects
follow, whether the head be removed above or
below the brain, and in the latter case a new
brain, with all its nerves, is speedily con-
structed. The collar and foot are also per-
fectly restored after their removal.

Slugs reproduce their horns as well as snails,
but their power of manufacturing a new head
is much inferior.

Muscular integument. — None of the Gaste-
ropoda have any thing analogous to an endo-
skeleton, a circumstance which sufficiently ac-
counts for the varied forms which the same in-
dividual assumes under different circumstances,
for the body being unsupported by any re-
sisting framework, readily yields to the con-
tractions of the muscular integument with
which it is covered. It is from this circum-
stance that the zoologist finds the preservation
of the natural forms of the recent animals a
task of such extreme difficulty, owing to the
corrugation and distortion produced by the or-
dinary modes of preservation; it is scarcely
possible indeed, in many cases, to recognise
with tolerable accuracy the natural appearance
of these creatures in the shrunken specimens
generally preserved in our cabinets, and the
collector of these objects would do well never
to omit, when circumstances allow him the op-
portunity, to preserve some sketch of the living
forms of such exotic species as may come into
his possession.

Body. — In the naked Gasteropods the whole
body is found to be inclosed in a muscular in-
tegument, the basis of which is a cellular web
of extraordinarily extensible character, in which
the muscular fibres may be seen to cross each
other in various directions, some passing longi-
tudinally from one extremity of the animal to-
wards the opposite end, while others, assuming
different degrees of obliquity, are interwoven
with the rest, so as to occasion the elongation
or contraction of the body in every assignable
direction. Within this muscular bag the vis-
cera are contained, as well as the organs sub-

GASTEROPODA.

403

servient to mastication, the apparatus of the
external senses, and of the organs employed in
copulation, which are, when unemployed, re-
tracted within its cavity by special muscular
fasciculi spoken of elsewhere.

Retractile muscles. — In the spirivalve genera
the muscular walls which inclose the body only
exist in such parts as, during the extended state
of the animal, are protruded from the shell ;
that part of the body which is concealed within
its cavity being provided with a much more
delicate and membranous envelope ; in such,
however, a necessity exists for an additional
muscular apparatus, serving to retract the body
and foot within the cavity of its calcareous
abode, and of course exhibiting various modifi-
cations of arrangement in conformity with the
shape of the shell itself. In the turbinated
shells, the retracting muscles consist of strong
fasciculi of fibres arising from the columella
or axis of the shell, and diverging from this
point, spread in several slips, which become
interlaced with the fibres composing the foot
and muscular investment. In the flattened
forms of Patella and Chiton, the muscular
fibres arise all around the margin of- the shell,
excepting at its anterior part; these penetrating
the mantle are intimately interwoven with the
muscles forming the circumference of the foot.
The animal of the Haliotis is fixed to its ex-
panded and semi-turbinated shell by a single
large and ovoid muscle, which takes its origin
from near the middle of the last spire ; what-
ever the disposition of these muscles, however,
their action is obviously of two kinds; and not
only are they the agents by which the creature
retires within its covering, but by raising the
central portion of the disc of the foot, whilst its
margins are in apposition with the plane of
progression, they will, by producing a vacuum
beneath, convert the whole apparatus into a
sucker, the adhesive power of which will be
proportioned to the extent of its surface.

Foot. — The foot of the Gasteropoda is their
principal agent of progression. It is generally
a fleshy disc, of variable size and shape, attached
to the ventral surface, and forming when ex-
panded an organ by means of which the animal
can adhere to surrounding objects. In the
naked genera it is small, but in the conchife-
rous species, especially in such as are provided
with dense and weighty shells, its dimensions
and force are proportionally increased. In its
internal structure it resembles the muscular in-
vestment of the body, of which in fact it is
merely an expansion, consisting of muscular
fibres interlacing each other in every possible
direction, as may be developed by continued
maceration. In the Slug, when opened from
the back, the superior layer of fibres is found to
run transversely, arising apparently from two
tendinous lines which run longitudinally near
the centre of the organ, and terminating near
the margins of the disc ; beneath these, longi-
tudinal fasciculi may be detected, but so inter-
laced with other fibres assuming every degree
of obliquity, that it is impossible to unravel the
complicated structure which they form. In the
Limpet (Patella) the lower fibres of the foot

are transverse, but near the circumference they
become distinctly interwoven with circular fas-
ciculi ; the superior stratum viewed from above
consists of two series of oblique fibres, which
meet at an acute angle on the middle line,
whilst the substance of the organ is composed
of muscular bands variously disposed : from
such a structure the movements of the foot are
readily understood ; the transverse fibres by
their contraction will elongate the ellipsis of
the foot by diminishing its breadth, whilst the
longitudinal, having a contrary action, will, by
the combination of their effects, produce every
movement needful for the progression of the
creature. On minutely inspecting the foot of
a terrestrial Gasteropod, as it crawls upon a
transparent surface, it will be found to be
divided into a certain number of transverse seg-
ments of variable size by a particular arrange-
ment of the longitudinal muscular fibres, which
seem to form, when the creature advances, un-
dulations limited by the points of contact.
These sections appear alternately to form a
vacuum upon the surface where the animal is
placed, that which follows advancing to take
the place of that which precedes it, the trans-
mission of movement occurring from behind
forwards, a mechanism which causes the animal
to advance by a slow and uniform progression.
The above structure of the foot, and conse-
quent mode of locomotion, although the most
usual, is susceptible of considerable modifica-
tion. Thus in Scyllaa, we find it only adapted
for grasping the thin steins of fuci and other
submarine plants, being for that purpose com-
pressed and grooved inferiorly into a deep sul-
cus. In the Tornatellafasciata, Lam. the struc-
ture of the foot is remarkable : beaten incessantly
by the waves, in the cavities of rocks which it
frequents, nearly on a level with the surface of
the sea, to the violence of which it is always
exposed, it has need of additional powers of
retaining its hold; its foot is therefore divided
into two adhering portions, placed at each
extremity, and separated by a wide interval ;
when it crawls it fixes the posterior disc and
advances the other, which it attaches firmly to
the plane of progression, and this being effected,
the hinder sucker is detached and drawn for-
wards, locomotion being accomplished by the
alternate adhesion of these two prehensile discs.
In Cyclostoma the foot is likewise furnished
with two longitudinal adhering lobes, which
are advanced alternately. But the foot is not
merely an instrument of progression on a solid
surface, in many species being convertible, at
the will of the animal, into a boat, by means of
which the creature can suspend itself in an in-
verted position at the surface of the water,
where by the aid of its mantle and tentacles, it
can row itself from place to place. The Buli-
mus stagnalis, so common in our pools of fresh
water, is a good example of this mode of sail-
ing ; and in the marine species, Aplysia and
Gastropteron may be enumerated as exhibiting
a similar structure.

Some of the naked Gasteropods, as Aplysia
and Thethys, are able to move through the
water in the same manner as the leech by an

404

GELATIN.

undulatory movement of the whole body, a
mode of progression which in Thethys is mate-
rially assisted by the membranous expansion of
the mantle placed around the anterior part of
the body, which forms a broad veil, and from
the muscular fibres contained within it, must
necessarily be an important agent in swim-
ming.

Particular secretions. — Many of the Gaste-
ropoda, in addition to the secretions which
have been mentioned, furnish others adapted
to peculiar circumstances, and produced from
special organs.

In the Snail and the Slug tribes a slimy
mucus is furnished in great abundance from an
organ which has been denominated the " sac
of the viscosity ;" this is a membranous bag sur-
rounding the pericardium, which when opened
is found to be divided internally by delicate
septa arising from its walls ; from this proceeds
a capacious duct, which follows the course of
the rectum, to which it is intimately united, to
open externally in the neighbourhood of the
respiratory aperture. The viscid secretion of
this gland spreading over the surface of the
foot is most probably an assistant in progres-
sion, causing it to adhere more intimately to
the surfaces over which the animal crawls.

Aplysia furnishes three distinct fluids issuing
from different parts of the body. The first is a
glairy mucus, which exudes in considerable
quantities from the surface of the mantle, espe-
cially when the creature is irritated. The se-
cond is a whitish liquor, which is thick and
acrid, and has been reputed venomous; it is
emitted in very small quantities, but its smell
is strong and highly nauseous: the gland which
produces it is a little reniform mass placed near
the vulva, close to which is the orifice of its
excretory canal. Blainville looks upon this as
the representative of a urinary apparatus, but it
does not appear to exist in all the species, and
is never emitted except when the animal is tor-
mented.

The third secretion is much more abundant
than the other two, and is generally of a beau-
tiful lake colour, except in Aplysia citrina, in
which it is yellow. It is contained in a spongy
substance, which occupies all those portions of
the little mantle or operculum to which the
shell does not extend. All the areolae of this
tissue are filled with a purple matter, the colour
of which is so intense, that when it is expressed
it has a black violet hue, but when mixed with
a large quantity of water, imparts to it the co-
lour of port wine. This colouring fluid seems
to exude through the skin of the mantle, no ex-
cretory duct having been found specially ap-
propriated to its escape : it is apparently pro-
duced from a triangular glandular mass situated
in the base of the mantle.

Several species of Murex secrete a similar
fluid, which, like the ink of the cuttle-fish,
serves as a defence from attack ; in all cases it
is expelled with force, and in such abundance
as to colour the water around to a considerable
distance.

There is a species of Limax, (Limax nocti-
lucus,) described by M . Orbigny, which produces

a phosphorescent secretion capable of emitting
a light of considerable brilliancy. The luminous
organ is a small disc of a greenish colour by
day-light, soft in texture, and slightly contractile.
The light is only visible when the creature is
expanded and in motion. The disc is always
covered with a greenish mucus, which, if wiped
off, is speedily renewed. It is found to be
connected with the generative organs, and ap-
pears to be principally useful during the season
of love.

BIBLIOGRAPHY. — Swammerdam, Biblia Naturae
seu Historia Jnsectorum, fol. 1737. Cuvier, G.
Le9ons d'Anatomie Comparee, 8vo. 1799. Ibid.
Memoires pour servir a 1'Jiistoire et 1'Anatomie des
Mollusques, 4to. 1817. De Blainville, de 1'Orga-
nization des Animaux, ou Principes d'Anatomie
Comparee, 8vo. 1822. Delle Chiaje, Memorie sulla
storia e notomia degli animali senza vertebre del
Regno di Napoli. Ferussac, Histoire des Mollus-
ques terrestres et fluviatiles, fol. Spallanzani,
Opuscoli di Fisica animale e vegetabile, 1776.
Reaumur, De la formation et de 1'accroisse-
ment des coquilles des animaux tant terrestres
qu'aquatiques, in the Memoires de 1'Acad. des
Sciences, 1709. He continued the subject in the
same work for 1716, under the title of Eclaircisse-
mens des quelques difficultes sur la formation et
1'accroissement des coquilles. Hatchett, on the
chemical Composition of Shells, Phil. Trans. 1799-
1800. Beaudant, Memoire sur la structure des
parties solides des Mollusques, Annales du Museum,
torn. xvi. p. 66. Weiss, M. Sur la progression des
Gasteropodes Terrestres, Journ. de Physique de
Rozier, An. i. p. 410. Lamarck, Systeme des Ani-
maux sans Vertebres, 7 vol. 8vo. 1815-1822. Har-
derus, Examen Anatomicum cochleae terrestris do-
miportae, Basileae, 1679.

( T. Rymer Jones.)

GELATIN (Fr. gelatine; Germ. Leim.
Gallerte). This term is applied to an im-
portant principle obtained by boiling certain
animal substances in water, and filtering or
straining the solution, which, if sufficiently
concentrated, gelatinises, or concretes into a
translucent tremulous mass on cooling, which
may be again liquefied and gelatinised by
heat and cold. Many varieties of gelatin
occur in commerce, of which glue is perhaps
the most important : it is obtained by boiling
the refuse pieces of skin and hide, and the
scrapings and clippings from the tan-yard, in
a sufficient quantity of water, till a sample
taken out of the boiler forms, on cooling, a
stiff jelly; the solution is then strained whilst
hot, and run into coolers, where it concretes, and
is afterwards cut by a wire into slices, which
are dried upon nets. Membranes, tendons,
cartilage, horn-shavings, and other similar sub-
stances also yield a jelly, which, however, is
less stiff and binding than the former, espe-
cially when obtained from young animals :
size is a jelly of this description. Isinglass,
which consists of several parts of the entrails
of fish, and especially the sound, &c. of the
sturgeon, yields a very pure and tasteless jelly,
which is chiefly used for the table; the jelly
of calves' feet and hartshorn-shavings is some-
what similar.

As jelly cannot be extracted by cold water,
and as we have no direct evidence of its
existence in the various substances from which

GELATIN.

405

it is obtained previous to the action of boiling
water, and, moreover, as it does not occur
in any of the animal fluids or secretions, it
has been regarded by some chemists, and
especially by Berzelius, as a product of the
action of water and heat, and not as a mere
educt. He compares its formation to the
conversion of starch into gum and sugar, and
remarks that in both cases the change is ac-
celerated by the presence of dilute acids.

Pure gelatin is colourless, transparent, in-
odorous, insipid, and neither acid nor alkaline ;
heat softens it and exhales a peculiar odour,
and it burns with smoke and flame, leaving
a bulky coal, difficult of incineration and
containing phosphate of lime : it yields much
ammonia, and the other ordinary products of
analogous animal compounds, when subjected
to destructive distillation.

In cold water dry gelatin swells and be-
comes opaque, and when gently heated it
dissolves and forms a clear colourless solution,
which gelatinises when cold. According to
Dr. Bostock, one part of isinglass to 100
parts of water yields a perfect jelly, but with
180 of water it does not concrete.* Those
modifications of gelatin which are the least
soluble in hot water yield the strongest jelly.
When the same portion of jelly is repeatedly
liquefied and cooled, it gradually loses the
property of gelatinising, and becomes so far
modified as to leave a brownish gummy residue
when evaporated, which readily dissolves in
cold water. L. Gmelin kept a solution of
isinglass in a sealed tube for several weeks
at the temperature of 212° : it was thus
changed to the consistency of turpentine, was
deliquescent, soluble in cold water, and par-
tially so in alcohol.

An aqueous solution of gelatin exposed for
some time to the air at the temperature of
60° to 70° becomes at first thinner and sour,
and afterwards ammoniacal and fetid : the
addition of acetic acid prevents the putrefac-
tion without impairing the adhesive power of
the gelatin.

Gelatin is insoluble in alcohol and ether,
and in the fixed and volatile oils. When a
strong aqueous solution of gelatin is dropped
into alcohol, it forms a white adhesive and
elastic mass, which adheres strongly to the
glass, and which, like dry gelatin, softens, but
does not dissolve in cold water.

When chlorine is passed through a warm
and somewhat concentrated solution of gelatin,
each bubble becomes covered with an elastic
film, and deposits, on bursting, a white, tough
viscid matter ; the whole of the gelatin is thus
precipitated, and free muriatic acid is formed.
This chloride of gelatin is insoluble in water
and alcohol, and remains acid, and smells
of chlorine, even after it has been kneaded
in warm water. Dissolved in caustic am-
monia in a tube over mercury, it evolves
nitrogen and becomes mucilaginous. It is
soluble in acetic acid; but the solution, though
rendered turbid by dilution, gives no preci-

* Nicholson's Journal, xi. 244.

pitate by ferro-cyanuret of potassium, so that
the gelatin is not thus converted into albumen,
No analogous compound is produced either
by iodine or bromine.

The action of sulphuric acid on gelatin
has been studied by Braconnot.* When one
part of glue and two of sulphuric acid are
mixed, they form in twenty-four hours a clear
fluid, which, when diluted with eight parts
of water, boiled for eight hours, (the loss by
evaporation being replaced by fresh portions
of water,) and then neutralised by chalk,
filtered, evaporated to the consistency of syrup,
and set aside for a month, yields a crystalline
crust of a peculiar saccharine substance, which
is insoluble in alcohol and ether, unsusceptible
of vinous fermentation, and gives ammonia
by destructive distillation. It combines and
forms a peculiar crystallisable compound with
nitric acid, which he calls the nitro-saccharic
acid, and which combines with the salifiable
bases and forms distinct salts, the properties
of which closely resemble the carbazotates.

Dilute nitric acid dissolves gelatin without
the evolution of nitrous gas, and forms a yellow
solution, which, by evaporation, (or the ad-
dition of an alkali,) becomes darker, and at
last evolves nitrous gas, and passes (often with
ignition) into a spongy coal.f By concen-
trated nitric acid gelatin is converted into
malic and oxalic acids, a fatty substance, and
artificial tan.]:

Acetic acid dissolves gelatin and the solution
does not gelatinise, but upon drying, the ad-
hesive power of the gelatin is unimpaired:
the dilute acids do not generally prevent ge-
latinisation.

Neither the dilute caustic alkalis nor am-
monia prevent the concretion of a solution of
gelatin, but they render it turbid by precipi-
tating its phosphate of lime. Gelatin is soluble
in strong caustic potash, with the exception
of a residue of phosphate of lime. The solu-
tion, when neutralised by acetic acid, does
not gelatinise, and yields on evaporation a
compound of gelatine with acetate of potash,
which is soluble in alcohol. Sulphuric acid
precipitates sulphate of potash from this acetic
solution, in combination with gelatin ; and
this compound precipitate, dissolved in water,
crystallizes by spontaneous evaporation to the
last drop.§

Hydrate of lime does not affect a solution
of gelatin, but much lime is dissolved by it :
it also takes up a considerable quantity of
recently precipitated phosphate of lime.

Gelatin is not precipitated by solution of
alum, but when an alkali is added the alumine
falls in combination with gelatin. The alu-
minous solution of gelatin is used for sizing
paper, and for communicating to woollen
cloth a certain degree of impenetrability to
water.

The acetates of lead do not precipitate pure
gelatin; by corrosive sublimate its solution is

* Annales de China, et Phys. xiii.

t Hatchett, Phil. Trans. 1800, p. 369.

\ Ibid.

6 Berzelius.

406

ORGANS OF GENERATION.

rendered at first turbid, and when excess is
added a white adhesive compound falls : nitrate
and per-nitrate of mercury and chloride of tin
occasion nearly similar changes. But the me-
tallic salt which is the most decided precipitant
of gelatin, and which does not affect albumen,
is sulphate of platinum ; it throws it down
even from very dilute solutions, in the form
of brown flocculi, which, when collected and
dried, become black and brittle, and which,
according to Mr. Edmund Davy, to whom we
owe this effective test, consist of about 76 per
cent, of sulphate of platinum and 24 per cent,
of gelatin and water.

We now come to the most important and
characteristic property of gelatin, which is,
that of combining with tannin, and upon
which the art of tanning, or the conversion
of skin into leather, essentially depends, for
the true skin (cittis) of animals consists of
a condensed and fibrous form of organised
gelatin, and, when properly prepared and im-
mersed in a solution of vegetable astringent
matter or tannin, it becomes gradually pene-
trated by and combined with it, and when
dried is rendered insoluble and durable. The
tannin of the gall-nut is perhaps that which
forms the most insoluble precipitate in gelati-
nous solutions, and is therefore the most de-
licate test of the presence of gelatin ; but, as
albumen is also thrown down by it, the absence
of the latter must have been previously ascer-
tained. (See ALBUMEN.) A strong infusion
of galls occasions a precipitate in water holding
less than a five-thousandth part of gelatin in
solution, and, if added to a strong solution
of gelatin, it throws it down in the form of
a curdy precipitate, more or less dense and
coloured according to the greater or less excess
of the precipitant. The precipitated compound
is insoluble in water, dilute acids, and alcohol,
and when dried becomes hard and brittle, but
again softens and acquires its former appear-
ance when soaked in water : it may be termed
tanno-gelatin. When tannin is added to a
solution of gelatin, the latter being in excess,
and especially if it be warm, no precipitate
is immediately formed, for tanno-gelatin, when
recently precipitated, is to a certain extent
soluble in liquid gelatin. Tanno-gelatin does
not appear to be a definite compound ; at least
it is difficult to obtain it as such : the preci-
pitate by infusion of galls consists, when care-
fully dried, of about 40 per cent, of tan and 60
of gelatin. When obtained by other astringents,
such as oak-bark, catechu, and kino, it differs
in the relative proportion of its components
and in its other characters, and often contains
extractive matter. According to Sir H. Davy,*
100 parts of calf-skin thoroughly tanned by
infusion of galls increase in weight 64 parts ;
by strong infusion of oak-bark 34, and by
weak 17; by concentrated infusion of willow-
bark 34, and by dilute 15; and by infusion
of catechu 19.

Mr. Hatchett's researches have shewn that
gelatin is also precipitated by the varieties

* Philos. Trans.

of artificial tan, and that the compound thrown
down resembles in its leading characters the
tanno-gelatin of natural tan. The ultimate
composition of gelatin (pure isinglass) has
been quantitatively determined by Gay Lussac
and Thenard, with the following results : —

Atoms. Equiv. Theory. Experiment.

Nitrogen . 1 14 16.09 16.998

Carbon . 7 4t 48.28 47.881

Hydrogen . 7 7 8.04 7.914

Oxygen . 3 24 27.59 27.207

1 87 100.00 100.000

As the combining proportion of gelatin has
not been accurately ascertained, its equivalent
number, as above given, is open to doubt,
but it is probably correct, and the theoretical
and experimental results closely correspond.

(W. T. Brande.)

GENERATION, ORGANS OF, (Com-
parative Anatomy). — Few subjects connected
with physiology have been investigated more
assiduously than that of the generation of ani-
mals ; and in none, perhaps, has the poverty of
our knowledge of the operations of nature been
more conspicuously exemplified. In studying
many functions of the animal economy, the
laws of chemistry and mechanics have been suc-
cessfully appealed to by the philosopher, and
their application to the operations of the animal
frame satisfactorily substantiated ; but in at-
tempting to explain the wonderful process by
which organized bodies are perpetuated, all the
resources of modern science have been found
totally inadequate to the task, and we are still
left to record facts and observations concerning
the structure of the organs appropriated to the
propagation of animals, without being in any
degree able to connect them with the results so
continually offered to our contemplation. In
taking a general survey of the animal kingdom,
we are at once struck with the infinite variety
of forms which it presents, adapted to an end-
less diversity of circumstances, and might expect
to meet with a corresponding dissimilarity in the
organization of the generative apparatus pecu-
liar to each : no such dissimilarity, however,
exists in nature, the modes of reproduction
conform to a few grand types, and the increasing
complexity of parts, apparent as we ascend to
higher classes, which it will be our business to
trace in this article, will be seen to depend
rather upon modifications in the arrangement
of secondary structures than upon any deviation
from the fundamental organization of the more
immediate agents.

Without entering upon any discussion con-
cerning the theories which have from time to
time been advocated relative to spontaneous
generation, we shall divide all animals as re-
lates to the generative function into three great
classes, grouping together such as are

1st. Fissiparous, in which the propagation of
the species is effected by the spontaneous divi-
sion of one individual into two or more, pre-
cisely resembling the original being.

ORGANS OF GENERATION.

407

2nd. Gemmiparous, in which the young
sprout as it were from the substance of the
parent.

3rd. Oviparous, producing their offspring
from ova or germs developed in special organs
adapted to their formation.

Of these modes of reproduction the two first
are confined to the lowest or acrite division of
the animal kingdom, whilst the third or ovipa-
rous type is common to all other classes.

Fissiparous generation is the simplest possi-
ble, and presupposes a corresponding simpli-
city of structure in the animals which propa-
gate in this manner. It is principally confined
to the Polygastric animalcules, most of which
are multiplied by the spontaneous separation of
an individual into two portions precisely resem-
bling each other, and capable of performing all
the functions which originally belonged to the
undivided creature. Some of the larger species
ofTrichoda are well calculated to exhibit to
the microscopic observer the steps by which
this process is accomplished : the animalcule,
prior to its division, is seen to become slightly
elongated, and a transparent line is gradually
distinguishable, indicating the course of the in-
tended fissure ; at each extremity of this line a
contraction of the body is speedily observable,
and the lateral indentations become deeper
and deeper, till at length a perfect separation
is effected. The direction in which this divi-
sion occurs is not always the same even in
the same species ; thus, instead of traversing
the shorter axis of the body it not unfrequently
assumes a longitudinal or oblique direction,
and from this cause it is not unusual to find the
newly divided creatures differing materially in
appearance from their adult or rather conjoined
form ; for in this process the old animalcules
literally become converted into young ones.

In some of the more complex forms of Poly-
gastrica the fissiparous mode of generation exhi-
bits modifications which are extremely curious.
In the beautiful Vorticelte, whose bell-shaped
bodies are supported on long and exquisitely
irritable stems, the division commences at the
large ciliated extremity of the animalcule, from
which point it gradually extends in a longitudi-
nal direction towards the insertion of the stem,
dividing the body into two equal portions, one
or both of which becoming speedily detached
from the pedicle, might easily in this state be
mistaken for creatures of a different genus, and
have in fact been described as such by many
authors. The new animalcule, when thus
deprived of its pedicle, is seen to be fur-
nished with cilia at the opposite extremity to
that on which they were previously found, while
from the other end, originally the mouth, a new
foot-stalk becomes gradually developed, and the
creature assumes the shape proper to its species.
If one of the bells remain attached to the pedi-
cle, it continues to perform the same movements
as before the separation of the new animalcule ;
but if both become detached, the foot-stalk
perishes.

In the strangely compound symmetrical bo-
dies of Gonium a provision for separation
appears to be made in the detached portions of

which each perfect animal is apparently com-
posed. The body of Gonium pectorale con-
sists of sixteen minute transparent globes of
unequal size, arranged in the same plane.
This beautiful animalcule is propagated by
a separation of its integrant spherules, the
creature dividing into four portions precisely
similar to each other, and composed individually
of one of the central globules united to three
of the smaller marginal ones ; and no sooner is
the division accomplished than the component
globes of each portion increasing in number,
the new animalcules assume the dimensions
and appearance of that of which they originally
formed parts.

In the Gonium pulvinatum the fissiparous
mode of generation gives origin to a still more
numerous progeny. The young animalcule is
a minute, flat, diaphanous and quadrangular
membrane, which swims through the fluid in
which it is found by movements sufficiently in-
dicative of its animal nature : as it enlarges, the
surface is seen to become marked by two series of
parallel lines which cross each other at right an-
gles and divide the creature into smaller squares,
which ultimately separate and become distinct
representations of the original animalcule.

Some of the Nematoid worms, as the Nais,
are likewise said to propagate by spontaneous
division.

Gemmipurous generation. — This mode of re-
production, like the fissiparous, is confined to
the lowest tribes of animal existence, and the
creatures which propagate in this manner are
unprovided with any apparatus specially appro-
priated to generation. The young appear as
gemmae or buds, which at certain periods sprout
from the homogeneous parenchyma which com-
poses the body of the parent, and these buds gra-
dually assuming the form of the original by a
kind of vegetative growth, become in a short
time capable of an independent existence. The
gemmiparous type of the generative function
is met with through a wider range of the animal
kingdom than the last, existing under modified
forms in many species of Polygastric Infusoria,
and of Polyps, as well as in Sponges, the Cys-
tiform Entozoa, and probably in some Acale-
phse.

It is in the Cystoid Entozoa that we find it in
its simplest form. In the Cysticercus and like-
wise in the Ccenurus, the transparent membra-
nous bag of which the animal consists is filled
with a glairy fluid, in which occasionally young
hydatids are seen floating about. These young
Cysticerci in the earliest period of their forma-
tion are seen to pullulate from the parietes of
the parent sac, and gradually enlarging they
ultimately separate from their connexions, be-
coming detached and perfect animals.

Many of the Polygastrica are multiplied by
a similar process, of which the Volvox globator
may serve as an illustration. This beautiful ani-
malcule is a minute diaphanous globe, which
under the microscope is generally seen to con-
tain a variable number of smaller globules, which
are the young : these, when first discoverable,
are attached to the inner surface of the parent,
but speedily detaching themselves they are

408

ORGANS OF GENERATION.

found rolling loosely within the body of the
larger animalcule, effecting their rotatory move-
ments by the agency of cilia of extreme minute-
ness, which under a good microscope are seen
to cover their external surface. The contained
globules having attained a sufficient maturity,
the parent volvox bursts, and thus by its own
destruction allows its progeny to escape from
their imprisonment. The multiplication of
these animalcules is effected with considerable
rapidity, and it not unfrequently happens that
even before the escape of the second generation
the gemmules of a third may be observed within
their bodies, which in like manner advancing
through similar stages of development will ter-
minate by their birth the existence of their
parent.*

It would appear from the observations of
Professor Grant, that in the sponges, notwith-
standing their different form, the process of re-
production is entirely similar. In these curious
animals the gemmules are developed in the
substance of that living parenchyma which
coats their porous skeletons, and when mature
are expelled through the foecal orifices to com-
mence an independent existence. When sepa-
rated from the parent sponge, these gemmules,
like those of the volvox, are ciliated over a great
portion of their surface, and being thus endowed
with a power of locomotion, are enabled to
swim to a considerable distance in search of a
situation adapted to their future growth, until
having at length selected a permanent support,
they become attached, and developing within
themselves the spicular or horny skeleton pecu-
liar to their species, they gradually assume the
porous texture and particular character of the
sponge from which they were produced.

But it is in the gelatinous Polypes that we
meet with the most perfect forms of gemmi-
ferous propagation : of this the Hydra viridis,
or fresh-water polype, affordsan interesting illus-
tration, and from the facility with which it may
be procured and examined by glasses of very
ordinary powers, it is well calculated to illus-
trate the mode of generation which we are at
present considering. The body of this simple
polype is transparent, and under the microscope
appears to be entirely made up of translucent
granules, without any trace of internal appara-
tus appropriated to reproduction. The gem-
mules by which it is propagated sprout from
some part of the surface, appearing first as mere
gelatinous excrescences, but gradually enlarging
they assume the form of their parent, acquiring
similar filamentary tentacles and a gastric
cavity of the same simple structure. As long
as the junction between the polype and its off-
spring continues, both seem to enjoy a commu-
nity of being, the food caught by the original one
being destined for the nourishment of both ; but
at length, the newly-formed animal having at-
tained a certain bulk, and become capable of
employing its own tentacles for the prehension
of food, detaches itself with an effort, and as-

* [Some physiologists, however, refer the genera-
tion of this creature to the fissiparous mode. See
the succeeding article.— ED.]

sumes an independent existence. This mode
of multiplication is exceedingly rapid, a few
hours sufficing for the perfect developement of
the young creature; and not unfrequently even
before its separation, another gemmule may be
observed emerging from the newly-formed
polype, soon to exhibit the same form and ex-
ercise the same functions as the parent from
which it sprouts'?

The propagation of some of the lithophytous
polypes resembles that of the hydra, the young
being produced from buds or gemmules, which
sprout from the living investment of their cal-
careous skeleton. Such are the Fungia, in
which the young are at first pedunculated, and
fixed to the laminse upon the upper surface of
the mass from which they spring ; in this state
they might readily be mistaken for solitary
Caryophyllia, but in time they separate from
the parent stock, and loosing the pedicle which
originally supported them, they assume the
form of their species.

Oviferous generation. — In the third, and by
far the most numerous division of the animal
kingdom, the young are derived from ova or
eggs, in which the germ of the future being is
evolved, and from which the young animals
escape in a more or less perfect state.

It will be seen that the ovum which gives
birth to all the higher animals differs essentially
from the gemma furnished by the gemmiferous
classes ; in the gemmiferous type the bud or
offshoot of the parent appears by a kind of
vegetative evolution to assume the proportions
and functions of the original from which it
sprang. The ovum we would define as a
nidus, containing not only the germ of the
future animal, but a sufficient quantity of nu-
tritious matter, serving as a pabulum to the
embryo during its earliest state of existence,
and supplying the materials for its growth until
sufficiently mature to derive them from other
sources. We have already shewn that in the
fissiparous and gemmiferous animals there is
no necessity for any special generative appa-
ratus, but in the oviferous classes we find, for
the most part, a distinct system, more or less
complicated in structure, in which the repro-
ductive ova are developed and matured. It
must be confessed, however, that in the present
state of our knowledge upon this subject we
are not prepared to state how far the existence
of a generative system is exclusively confined
to the ovigerous type. We are well aware
that many authors describe generative canals
to exist in several of the polypiferous tribes,
although the reproductive germs produced from
them resemble in their ciliated organs of pro-
gression and mode of development the gem-
mules of less elaborately organized polypes ;
yet, on the other hand, as we have abundant
evidence to prove that such polypes as have the
ovigerous canals most distinctly formed, as the
Actiniae for instance, produce their young per-
fectly organized and evidently developed from
true ova, we are content, in the present state of
our knowledge upon this subject, to regard the
presence of generative canals as co-existent
with ovigerous generation, andv shall leave

ORGANS OF GENERATION.

409

future observations to determine more accu-
rately the mode of reproduction in the corti-
ciferous polypes, which is a subject at present
involved in much contradiction and obscurity.
Taking this view of the subject, we find,
upon cursorily glancing over the ovigerous
classes of animals, that important modifications
of structure in the generative system render
further classification necessary, "in the lower
forms, ovigerous organs only have been dis-
covered, in which the ova are secreted, and
when matured, escape from the body, fit in
every respect for the production of a new
animal. In other instances, in addition to the
apparatus immediately appropriated to the de-
velopement of the ova, we find a superadded
portion destined to furnish a secretion which is
essential to their fertility, forming an apparatus
of impregnation. Sometimes the impregnating
organs are found in every individual, appended
to the ovigerous parts, rendering each creature
sufficient for the impregnation of its own ova :
in other instances, although each animal pos-
sesses both ovigerous and impregnating or-
gans, the cooperation of two individuals or more
is necessary to fertility; and in other cases
again, the apparatus which furnishes the ova,
and that destined to the production of the im-
pregnating fluid, are found in distinct indivi-
duals, distinguished by the appellations of
male and female: we shall accordingly di-
vide all oviparous animals into the following
groups : —

1. Such as are provided with ovigerous
organs only.

2. Animals having, in addition to the ovige-
rous apparatus, a glandular structure, the
secretion of which is probably subservient to
the fertility of the ova.

3. Ovigerous and impregnating organs, co-
existent in each individual, but the cooperation
of two or more needful for mutual impregna-
tion.

4. The ovigerous and impregnating appa-
ratus existing in distinct individuals.

FIRST DIVISION.— Animals in which ovigerous
organs only have been distinctly recognized.

It would seem from the observations of
Ehrenberg that some of the Polygastrica be-
long to this division, although the exact nature
of the generative system in such species remains
still a matter of uncertainty. In the Kolpoda
Cucullus the spawn consists of a loose mass
of ova, connected by delicate filaments, from
which the young are gradually evolved after
their extrusion from the parent animalcule, and
some of the parenchymatous Entozoa appear
to be similarly circumstanced.

In the Acalephae, at least in such as have
been most attentively examined, the generative
system conforms to the type at present under
consideration. From the researches of Gaede
and Eysenhardt it appears that the ovaria are
four in number, disposed in a cruciform manner
upon the dorsal aspect of the body or that
which is opposite to the mouth. These ovaria,
which at certain seasons of the year are re-
markably distended and often beautifully

VOL. ii.

Coloured, open into the interior of the stomach.
The young Medusae are hatched in the ovaria,
and afterwards escaping into the alimentary
canals excavated in the substance of the body,
acquire in that situation a very perfect state
of development, and are ultimately excluded
through the oral aperture, or in the Rhizosto-
matous species through the ramified canals of
the pedicle.

In the fleshy polypes (Actiniae) the ovigerous
system consists of long, convoluted filiform,
tubes, contained between the stomach and the
parietes of the body, and separated by partitions
which divide that space into compartments.
These tubes are attached by a delicate mesen-
tery, and according to Spix open in an irregular
manner into the digestive cavity, into which
the ova escape. The period or mode in which
the eggs are hatched is unknown, but that the
young escape fully formed and in every point
resembling their parent through the stomachal
orifice is attested both by Dicquemare and
Blainville.*

The different forms of Echinodermata pre-
sent a similar simple arrangement of the gene-
rative apparatus. In the Asteriadae each ray
is furnished with two clusters of short ovigerous
tubes, which are closed at one extremity, but
open at the other into a cavity common to each
group. These organs open by a series of aper-
tures placed around the circumference of the
mouth at the base of each ray. In the spring
these ovaria are distended with eggs of a
reddish-brown colour, which are expelled in
clusters and left upon the beach exposed to
the influence of the sun, where they are ulti-
mately hatched .f

The radiated type of structure is likewise
manifest in the disposition of the generative
organs of the Echinidse : in these the ovaria
are never single or simply bilobed, but are at
least four in number, or, as is generally the
case, five. Each ovigerous organ consists of
a simple dilated sacculus, which at certain
seasons is distended with ova, and at such
times in some species, as in the edible Echinus,
the eggs are sought after as an article of food.
The ovaria open externally by a corresponding
number of simple apertures, which are placed
around the anal orifice when it is central, but
otherwise are considerably removed from this
point. Nothing analogous to a male apparatus
has been detected in the Echinida. The eggs
are deposited in spring in the recesses of rocks
or among the fucus which covers them ; and
before they are hatched the young may be dis-
covered in the interior partially covered with a
calcareous shell, the rest of the integument
still remaining membranous.

* Spix and Delle Chiaje assert that there are
other filiform tubes mixed up with the ovarian ducts,
which they regard as the testes, but neither the
observations of other authors nor our own exami-
nations confirm this view of the subject.

t Tischer and Spix describe a singular flexuous
intestiniform organ which is found upon the dorsal
aspect of the stomach as a male apparatus, and
Blainville considers this part as in some degree
connected with generation.

2 E

410

ORGANS OF GENERATION.

The Holothurldse present in the elongated
form of their bodies an evident approximation
to the annul ose type of structure, and a propor-
tionate concentration of the generative system ;
in these we find but one ovary floating loosely
in the visceral cavity, and composed of numerous
very long cceca, which terminate by a single
orifice placed on the median line, near the oral
extremity of the animal.* The eggs when dis-
charged are connected into masses composed
of long strings of ova, but the mode of their
development is but little known.

Although from the relations of the Mollus-
cous division of the animal kingdom we might
infer that a more elevated type of structure
would characterize their organs of reproduction,
the present state of our knowledge of the
anatomy of these creatures compels us to arrange
the lowest orders of that extensive class with
those tribes which only possess an ovigerous
system; for although an androgynous confor-
mation is presumed by many to exist in all
Bivalves, the presence of any superadded im-
pregnating portion has not yet been pointed
out, and even the course of the ova in their
passage from the ovarian cavity remains a mat-
ter of speculation. In the Conchiferous order,
from causes sufficiently obvious when we con-
sider the peculiar structure of the animals
which compose it, the full development of
their numerous ova could not be accom-
plished in the ovary itself, which occupies a
large portion of the body, as any material in-
crease of bulk produced from this cause would
materially interfere with the closing of the
shell; at an early period, therefore, the ova
are transferred from the nidus in which they
were formed to the branchial fringes, between
the laminae of which they perfect their growth,
and are fully exposed to the influence of the
element around them. Oken traced a canal
through which he supposed the ova to be con-
veyed directly from the ovaria to the gills ;f
but notwithstanding his observations Carus
contends J that the eggs pass into the stomach
through one of the openings hitherto considered
as belonging exclusively to the biliary ducts,
whence they are evacuated through the mouth
and conveyed into the openings of the gills
by the water which flows between the pallial
laminae from before backwards, and ultimately
escape by two canals which open below the anal
tubes.

In the Tunicata, and also in those forms of
the Gasteropodous Mollusca which most nearly
approximate the Conchifera in the details of
their organization, the ovary is imbedded in
the substance of the liver, and the ova are dis-

* Here, also, Blainville conjectures that there is
a supplementary impregnating portion, but it is
evident that in a treatise like the present it
would be worse than useless to recapitulate the
surmises of authors upon subjects only capable of
solution by positive demonstration, and we shall
therefore endeavour rather to adhere strictly to the
narration of what is clearly established by observa-
tion, than to indicate what theory or analogy would
lead us to suspect.

f Goetting, gel. Anzeigen, 180(5.

J Introduct. to Comp. Anat.

charged through a simple duct, unprovided
with any appendage which can be looked upon
as a male apparatus. It is true, indeed, that
in all these cases the walls of the oviduct may
themselves furnish a fertilizing fluid, and by
many physiologists they are supposed thus to
supply the want of male parts ; such an hypo-
thesis, however, is, to say the least of it,
entirely gratuitous ; but as it is more our busi-
ness to trace the development of organs than
the modes in which their deficiency may be
supplied, we are content to leave the question
without further discussion in this place.

SECOND DIVISION. — Animals provided with
ovigerous organs combined with an addi-
tional secreting structure, probably sub-
servient to the fertilization of the ova.

In this type of the generative system it must
be obvious that the function attributed to the
superadded portion is by no means indubitably
substantiated, the opinions of physiologists
relating to its office being rather based upon
analogical reasoning than supported by direct
evidence; and, in fact, some authors deny
entirely that a necessity for the impregnation
of the ova is more evident in this division than
in the last. Nevertheless, although it is im-
possible distinctly to prove the identity in
function between the appended portion and
the testis of higher forms of organization, the
evidence afforded from the position which it
invariably occupies, and from the considera-
tion of the parts connected with generation in
difficious animals to which we are insensibly
conducted by this species of Hermaphrodism,
is sufficiently cogent to warrant our application
of the term ovarium to the nidus wherein the
ova are produced, and to justify us in designa-
ting the accessory organ as a testis or apparatus
for impregnation.

The Taenioid Sterelmintha furnish us with
one of the simplest examples of this arrange-
ment of the generative organs. In the long
and tape-like bodies of these Entozoa each
segment, with the exception of the smaller ones
near the head, possesses distinct ovigerous and
impregnating structures. The female part of
the apparatus occupies the centre of the joint,
and consists of lateral tubes ramifying from a
central canal, which at times may be seen to
be full of minute granular ova. From these
ovigerous canals a duct issues, which commu-
nicates with the lateral pore and receives before
its termination two delicate tubes, recognizable
under the microscope as dark lines imbedded
in the pulpy segment, and which may be pre-
sumed to furnish an impregnating secretion.

In the Rot if era, or wheel-animalcules, the
female apparatus consists of two long and
comparatively wide sacculi, in which the ova
are developed ; these open at the anal orifice,
and receive near this point two narrow coeca,
which, as in the last case, may secrete a fer-
tilizing fluid, serving to impregnate the eggs
prior to their expulsion. The ova of these
minute creatures, before the escape of the
young, are exceedingly beautiful subjects for
the microscope, the wheels of the embryo

ORGANS OF GENERATION.

411

being easily distinguished in rapid action
through the pellucid coverings of the egg.

In the Cirrhopoda we have most probably
an example of this mode of generation, pre-
suming, that is, that the opinions of Cuvier
upon this subject are correct. These opinions,
it is true, have been disputed by various
authorities, as will be evident on reference
to the article CIRRHOPODA ; but their correct-
ness has been so fully supported by the
dissections of John Hunter, recently given
to the world,* that it seems best at least to
pause before repudiating the conclusions to
which these great anatomists, unacquainted
with the labours of each other, were indivi-
dually conducted. In the Cirripeds the ovaria
are two in number, placed on each side of
the stomach ; the two oviducts which proceed
from these unite to form a single elongated
tube, the parietes of which are thick and
apparently glandular. It is evident that in this
case the walls of the common canal, or ovipo-
sitor as it is usually termed, may serve to
secrete a seminal fluid, impregnating the eggs
at the period of their extrusion ; and such,
in the opinion of the authors above mentioned,
is a part of its office.

THIRD DIVISION. — Ovigerous and impreg-
nating organs co-existent, but the co-
operation of two individuals necessary
for mutual impregnation.

This arrangement of the generative system
occurs in some of the Parenchymatous Entozoa,
in the Annelida, and also in the Pteropod and
some Gasteropod Mollusca. Some of the
Entozoa, as Fasciola and Planaria, furnish
the simplest examples of this hermaphrodite
condition. In these creatures the male organs
consist of spermatic cceca, communicating with
a minute extensible penis, which is placed
behind the oral sucker. Near the penis a
small orifice is seen, leading to the ovigerous
canals, which have no communication with
the impregnating apparatus ; and the copula-
tion of two individuals is thus indispensable
to a reciprocal fertilization of the ova.

Those of the Annelida in which the gene-
rative system is best understood are androgy-
nous, and mutually impregnate each other,
although it is probable that in the tubicolous
genera, which are immoveably fixed to the
same spot, and almost deprived of locomotion,
each individual may in itself be sufficient for
reproduction.

In the Abranchiate and Dorsibranchiate
Annelida the male apparatus is composed of
several pairs of secreting bodies, arranged on
each side of the mesial plane, those of the
same side communicating with each other by
a common vas deferens. In the Leech the
vasa deferentia, which convey the secretion of
the numerous testicular masses, terminate in
a long protractile tubular penis, and at a short
distance behind this the opening which leads

* Catalogue of the Physiological Series of Com-
parative Anatomy contained in the Hunterian
Collection, vol. i.

to the female parts may be discovered. These
latter consist of a simple uterine sacculus, or
receptacle for the ova, to which two minute
ovaries are appended. The congress of two
individuals is effected by the reciprocal in-
troduction of the organs of intromission into
the vulvse. In the Earthworm and Nais the
intromittent apparatus is deficient, so that
some authors have even doubted that the
process of copulation, which is undeniably
essential to fecundity, does more than stimulate
each individual to self-impregnation. In the
Earth-worm, as well as in Arenicola and
Aphrodita, the ova, after escaping from the
ovaria, are retained in the cellular meshes
which surround the alimentary canal, in which
they are not unfrequently hatched, the young
being most probably expelled through a tubular
aperture at the posterior extremity of the body.
As regards the generative system, the Pte-
ropod Mollusca approximate the more complex
type seen in the Gasteropoda. In Clio lorealis,
the ovary, which is partially enveloped by the
liver, gives off a slender duct, which, after
a short course, plunges into a glandular tube ;
this, becoming gradually narrower, terminates
in a round sac placed on the left side of the
head, where it opens externally : near this
point is the penis, or organ of intromission,
communicating with a small sacculus, by
which the male secretion is probably furnished.

Fig. 200.

Testia of Helix.

The most complicated forms of this species
of hermaphrodism are met with in the Gas-
teropod division of Mollusca, existing through-
out the Nudibranchiate, Tectibranchiate, In-
ferobranchiate, and Heteropod orders, as well
as in those pulmonary genera which are un-
provided with a calcareous operculum. In
all these cases the testis is single and divided
into lobuli, connected together by the divisions
of the vas deferens so as to exhibit a racemose
arrangement, and each lobule, on minute in-
spection, is found to consist of little peduncu-
lated vesicles (Jig. 200). A slender vas defe-
rens conducts the secretion of this testicle to
the base of an intromittent organ of a most sin-
gular description ; this is a muscular tube of
great length, which, when not in use, is in-
verted and concealed within the body, but ca-
pable of protrusion at the will of the animal.
The female portion of this system is composed
of one ovary, provided with an ample and
tortuous oviduct, which serves, indeed, as a
kind of uterus or egg receptacle, wherein the
2 E 2

412

ORGANS OF GENERATION.

ova are retained until ripe for extrusion.
Near the termination of this oviduct are placed
several additional appendages, some of which
are apparently destined to furnish an invest-
ment for the ova, whilst one, which is con-
stantly present, is probably a reservoir for the
seminal fluid required to fertilize the eggs
as they are expelled. (See GASTEROPODA.)"

The external parts are so disposed that
during the copulation of two individuals the
male organ of each is introduced into the
orifice leading to the female apparatus of the
other, both thus impregnating and being im-
pregnated at the same time.

In Lymnata stngnalis we have a curious
exception to this mode of copulation, for in
this animal the sexual organs are so placed
that mutual impregnation is impossible, and
accordingly fecundation is accomplished by a
combination of individuals, each of which
performs the office of a male to another, while
to a third it acts the part of a female, and long
strings of them are often seen thus united.

FOURTH DIVISION. — Sexes distinct, that is,
the ovigerous and impregnating organs
placed in separate individuals.
This type of the reproductive apparatus
extends through a wide range of animals, and
is found in a great number of classes utterly
dissimilar in outward form and internal struc-
ture ; so that, in order to give a connected view
of the comparative organization of the parts
of generation, we shall be unavoidably com-
pelled to group together animals widely sepa-
rated by the laws of zoological arrangement.
Feeling, however, that by so doing we shall
lay before our readers a much more easily
intelligible comparison of the organs belonging
to our subject, we shall not scruple to bring
together, in one view, analogous forms of the
generative apparatus, in whatever classes they
may be found. Animals in which the sexes
are distinct may be divided into three classes;
the first including such as are oviparous, the
second embracing the ovo-viviparous orders,
while the third will comprehend the strictly
viviparous animals. It will be seen that
the terms here employed have been used
from time immemorial, but nevertheless in a
widely different sense to that in which the
present state of our knowledge sanctions
their application. To us it appears that we
ought to regard all creatures as ovipa-
rous whose offspring, at the period of their
escape from the ovum, are sufficiently mature
to admit of their independent existence. In
the ovo-viviparous division, on the contrary,
the ova are hatched and the embryo expelled
at an early period of its formation ; the embryo
is thus born in an extremely imperfect state,
the materials for its future developement being
supplied by the mammary secretion of the
parent ; such is the case with all the marsupial
orders. In the vivipara the earliest stages of
growth are precisely similar to those which
mark the progress of evolution in the ovi-
parous type, and the provisions made for
the nourishment of the rudimentary being in

every respect analogous ; the great distinction
consists in the subsequent maturation of the
embryo within a uterine cavity, and the forma-
tion of a placenta, which characterizes the
highest form of mainmiferous animals.

The oviparous classes, which form by far
the most numerous division, produce their
young from ova, in which the germs of the
future beings are developed for the most part
subsequent to the expulsion of the egg from
the body of the parent. In this case the
ovum necessarily contains a sufficient store of
nourishment for the support of the embryo
during the whole period of foetal life, at the
termination of which it is produced in a suffi-
ciently advanced stage of its growth to render
it capable of independent existence. It will
readily be perceived that under this division
we include many animals which, according
to the old meaning of the terms, were looked
upon as ovo-viviparous or viviparous in their
mode of reproduction ; a distinction which, as
the words have been hitherto applied, appears
to the writer by no means sufficiently grounded
upon physiological views to admit of its conti-
nuance. It is certainly very true that some ani-
mals included in this division are found to pro-
duce their young in a living state ; but the mere
hatching of the egg within the oviductus of
the mother, instead of subsequent to its ex-
pulsion, is not a circumstance of sufficient
importance to be regarded as constituting
another type of the generative process, more
especially as such an occurrence is entirely
fortuitous, observation having proved that the
same animal at one time produces its young alive
and at another in the egg state, in obedience
to circumstances connected with food, tem-
perature, or confinement. With this extension
of the term, oviparous animals in which the
sexes are distinct will be found in many classes
belonging to the diploneurose, cyclogangliate,
and vertebrate divisions of the animal kingdom,
combined with modifications in the structure
and arrangement of the generative apparatus,
which it will be our business to trace.

The earliest appearance of this type is found
in the cavitary Entozoa (Ccelelmintha), and the
sexual organs, both in the male and female
of these creatures, may be regarded as ex-
hibiting the greatest possible simplicity of
structure, consisting merely of secreting tubes,
which in one sex produce the seminal fluid,
in the other develope the ova. The seminal
organ, or testis of the male, is generally a
single tube of extreme length and tenuity,
winding in large folds around the alimentary
canal, and occupying a large portion of the
abdominal cavity ; when unravelled, its length
is found to be many times that of the animal ;
at one extremity it dwindles down to a filament
of the utmost tenuity, which floats loosely
in the juices of the body, whilst at the op-
posite end it terminates in a prolonged tubular
penis, or organ of intromission, placed near
the anal orifice. In the females of some
species, as in Ascaris, the ovigerous system
is composed of two tubes, each exceeding in
length and tortuosity the seminal vessel of the

ORGANS OF GENERATION.

413

male, and measuring in some cases upwards
of six feet. These tubes, after becoming con-
siderably increased in size so as to form a
kind of receptacle for the ova which they
generate, unite prior to their termination in
the vulva, the aperture of which is found upon
the ventral surface of the body at about one
third of its length from the anterior extremity.
In Strongylus the ovarian tube is single, and
its orifice nearer to the mouth. In many
species, as Filaria, the young are produced
alive, the ova being hatched in the oviduct,
a sufficient proof of internal impregnation
having been accomplished.

The Myriapoda, in every part of their struc-
ture, form the transition from the Annelida to
the articulated classes properly so called. They
are divided by entomologists into two classes,
the lulidtf or Chilog7iatha, and the Sculopen-
drldiE or Chilopoda, a division strictly in con-
formity with their internal structure; the former
i»i fact represent the Annelida; like the Abran-
chiate division of that class, they breathe by
air-sacs, communicating with spiracles seen
upon the exterior of their bodies. The Scolo-
pendrae, on the contrary, respire by tracheae,
which permeate their viscera, as in the insect
classes. In the generative system of these
creatures a similar relationship is evident. In
luluSf the generative system occupies the ante-
rior segments of the body, the sexual apertures
being found upon the rings near the cephalic
extremity, whilst in Scolopendra they are placed,
as in insects, near the anal orifice. As regards
the internal sexual organs of lulus, but little is
known conclusively, and our own researches
upon this point have not been sufficiently satis-
factory to enable us to speak positively con-
cerning them, although the result leads us to
suspect that in these creatures not only are the
sexual parts analogous to those of the Anne-
lida, but that, as in many of that class, the ova
are retained in cellular interstices surrounding
the intestinal canal for some time prior to their
expulsion.

In the Scolopendra the generative organs are
more easily distinguishable, and much resem-
ble those of insects ; they are, however, exceed-
ingly curious. Inj^f. 201 we have represented
the male apparatus of the Scolopendra mnrsi-
tans. The testes (o, a, a) are seven in number,
and closely packed in parallel lines; each testis
is composed of two parts, precisely similar to
each other, which are seen separate at b ; from
each extremity of the fusiform testis arises a
narrow duct, so that there are fourteen pairs of
ducts arising from the fourteen secreting organs.
Each of the testicular bodies is hollow inter-
nally. The ducts ultimately end in a common
tube (c), which soon becomes enlarged and
tortuous, terminating by a simple aperture near
the anus. Just prior to its termination, the en-
larged canal receives five accessory glands, four
of which (rf, rf, d, d) are intimately united, until
unravelled, as seen in the figure, while the fifth
(e} is a simple caecum of considerable length.

The ovarian system of the female Scolopen-
dra is a single tube, apparently without secon-
dary ramifications.

Male generative organs of the Scolopendra motsttans.

Insects. — In the numerous and diversified
tribes of the insect world a great uniformity is
observable in the general arrangement of the
generative apparatus. The sexes are invariably
separate, but while the internal organs are con-
stantly double and symmetrically disposed on
both sides of the mesial plane, the external
parts which are subservient to copulation are
removed to the posterior extremity of the body,
and are single. Throughout the whole class
the sexual system only arrives at that state of
perfection which is compatible with reproduc-
tion in the perfect or imago state of the animal,
although it may be detected in a rudimentary
form even in the larva, being gradually more
and more perfected during the developement
of the pupa. The business of procreation in
insects thus exclusively belonging to the per-
fectly formed creature, is accomplished only at
the termination of their existence, and the whole
tribe is remarkable from this circumstance.

The internal generative organs in male in-
sects are described as consisting of three por-
tions, the testes with their rasa deferentia, the
vesiculae seminales, and the canalis excretorius.
The testes, or, in other words, those portions of
the apparatus which are supposed to furnish
the essential part of the fecundating fluid, like
the rest of the glandular system, consist of coeca
or utricles floating loosely in the abdominal

414

ORGANS OF GENERATION.

cavity, immersed in the juices of the body,
from which they derive their secretion. Never-
theless, although essentially constructed upon
similar principles, the testicular coeca present a
singular diversity of form in different genera,
and some of the modifications are sufficiently
curious, although in the present state of our
knowledge it would be hopeless to attempt to
explain the reason of their existence. Miiller,
from a comparison of the researches of various
authors upon this subject, has given the follow-
ing summary of the principal forms of the
sperm-secreting organs, and although the cata-
logue of varieties might doubtless be considera-
bly extended, those given will abundantly an-
swer our present purpose. Beginning from the
tubular vessel, which is the simplest form of
the testis, he traces it through the various com-
plications here enumerated.

1. Simple tubes not branched, but more or

less convoluted and closed at one extre-
mity.

2. Spiral tubes similarly closed, as in Spho-

drus terricola.

3. Spiral tubes rolled up into little balls, as

in Carabus auratus, Aptinus duplotor,
Dytiscus, &c.

4. Simple tubes irregularly branched, each

branch vesicular near its extremity, as
in Prionus coriarius.

5. Simple tubes, divided in a verticillate

manner, each division being terminated
by a capsule ; Searabaut nasicornis,
(Swammerdam.)

6. Simple tubes, divided as the last, but

each division ending in a vesicle, as in
Trich iusfasciatus.

7. Simple tubes ending in stellated capsules,

the apices of which are produced into
slender tubes; Nepa cinerca, (Swam-
merdam.)

8. Simple tubes giving off a series of canals,

each of which is terminated by a disc-
shaped capsule ; Cetonia uurata.

9. Simple tubes, ending in flower-shaped

capsules, i. e. each capsule consisting
of a central vesicle, with other smaller
ones placed around it, as in Asida gigas,
(Edemera calcaratu, Diaperis violacea,
Tenebrio obscurus, (Edemera carulea,
&c.

10. Simple tubes, each terminated by a trans-

verse capsule, resembling the anther of
a flower, as in Apis, Bombyjc, Scaris,
Calvinia, Sac.

11. Simple tubes, dividing into minute radia-

ting utricles ; Bostrichus capucinus.

12. Simple tubes, each terminated by a cap-

sule, which is covered externally with
innumerable little vesicles or utricles, as
in Musca asilus, Elater murinus, Blaps
g'gtts, Telephones J'uscus.

13. Simple tubes, ending in an elongated sac-

culus,to the sides of which are appended
small vesicles arranged in longitudinal
rows, as in Semblis bicuuduta.

14. Simple lubes terminating in verticillate

utricles, as in Clerus ulveolarins.
15. Simple tubes, from which arise utricles

18.

19.

Fig. 202.

arranged like the teeth of a comb, as in
HydrophUw piceus.

16. Simple tubes, terminated by a simple sac-

culus ; Gyrinus natutor.

17. Simple tubes, terminated by a bunch of

vesicles.

Simple tubes, dividing into minute canals,
forming a kind of cauda equina ; Tri-
chodes apiarius.

Branched tubes, each branch being termi-
nated by a vesicle, as in Staphilinus
maxillosits. ( Fig. 202 .)

20. Tubes very much branched, some of the

ramusculi ending in bunches of leaf-
like utricles, others dilating into pe-
dunculated vesicles ; Sulpha obscura.
(Fig. 203.)

21. Simple loculated utricles, as in Ephe-

mera.

It is manifest from this sur-
vey that, although the secern-
ing organs differ so much in
form, the canals composing
them invariably terminate in
blind extremities ; nor is it
less obvious that the nature
of the testis does not depend
upon any peculiar arrange-
ment of the seminal tubes, but
upon the increase of surface
obtained by the various ar-
rangement of the vessels. Se-
cretion, therefore, here, as in
every other case, is effected by
the internal surface of tubes,
utricles, sacculi, &c. the same
end being accomplished in
some cases by means of very
long simple canals, which in
others is effected by smaller Testicle of Staphy.
branches, tubes, or agglome- linus maxillosus.
rated vesicles.

Fig. 203.

Testicle of Silpha obscura.

Appended to the excretory ducts of the testi-
cular organs, near their termination, is found a
group of ccecal tubes, evidently destined to
provide an accessory secretion; these have been
named from analogy vesicula scminales. They

ORGANS OF GENERATION.

vary much in their form, being sometimes elon-
gated, tortuous, convoluted, or ventricose, or at
others short and straight. The seminal vesicles are
generally two in number, even in those Lepi-
doptera in which the testis is single. In some
insects, as Tenebrio molitor and Hydrophilus
j>iccus, there are four; in others, as Dytucut
rnarginalis, six ; and in Locusta and Blatta,
they are very numerous. In some insects these
tubes are found to be of surprising length;
thus in On/ctes nasicurnis they are twenty
times as long as the body, and in Cetonia aurata
even sixty times the length of the animal. The
vasa deferentia and vesiculae seminales ulti-
mately terminate in one common tube, the ca-
nal is excretorius, which communicates with the
root of the penis; this canal is composed of
muscular walls largely supplied with tracheal
vessels, serving as a receptacle for the genital
secretions, and no doubt is the agent by which,
during coition, their expulsion is effected. The
penis of insects is a hollow tube, capable of
being protruded from the anal extremity of the
body : its texture is generally membranous,
but sometimes horny, and its shape exhibits
considerable variety ; it is usually cylindrical
or nearly so, becoming more slender towards
its termination. In Chermis pyms, however,
the end is enlarged ; in the common wasp
it is spoon-shaped; in Crabro bilobed, and in
some l"csp<e curved and bifid at its extremity.
In Musca vivipara its apex is covered with
spines ; in Tyrophaga putris and some other
Muscidae it is spiral. The penis of Coleoptera
is furnished with a bivalve sheath, destined to
open the vulva of the female prior to its inser-
tion. In some Diptera (Muscidae) a remark-
able inversion of the usual arrangement of the
organs of copulation is observable ; in these the
females are provided with a retractile penis,
whilst in the males the generative apparatus
terminates by a simple aperture. During coi-
tion in this case, it is the penis of the female
which is introduced into the genital opening of
the male, and thus becomes the recipient of the
fecundating fluid. The Dragon-flies (Libel-
lula) are remarkable from the position which
the male organ is found to occupy, being placed
under the anterior part of the elongated abdo-
men, but in the female the sexual aperture
occupies the usual situation near the anus.
This arrangement accounts for the singular
position which these insects assume during
copulation.

In addition to the organs above enumerated
as composing the male system in insects, we
may notice appendages which are found in
some tribes which materially assist in effecting
the intercourse of the sexes : these are named
prehensores, and serve to seize and secure the
female during coitus. These holders assume a
great variety of shapes, and likewise are diffe-
rently disposed according to circumstances.
They generally surround the aperture through
which the penis is extruded, but in Libellula
the mode in which the sexes embrace each
other renders additional security indispensable;
in tins tribe, therefore, besides the anal prchcn-
sores, an additional pair of forceps is placed

under the second abdominal segment. The
prehensores are generally two in number ; but
in many Lepidoptera, Conopis and Libellula,
three are placed around the anus. In Culex
there are two pairs. In Locusta morbUluste
there are five, and in Formica six holders. In
some tribes, as Megachilis, Agrionidas, and
Locusta, they are retracted within the abdomen
when not employed.

In insects the ovigerous or female generative
apparatus consists likewise essentially of tubes
or cceca, the arrangement of which is tolerably
uniform. They may be divided into the ovaria,
the oviducts, the spermotheca, or receptacle
for the seminal fluid of the male, the accessory
glands, and the ovipositor, which latter is, in
many insects, an instrument adapted to intro-
duce the eggs at the period of their extrusion
into situations suited to their developement.

The ovaria are double throughout the whole
class, each being composed of a variable num-
ber of membranous tubes arising from the
oviduct. Rifferschweils considers the ovaries
to be formed upon two primary types, being
either Jlagelliform, that is, composed of conical
tubes of equal length, which are inserted at the
same place at the extremity of the oviduct, as
in the Lepidoptera, the Bee, &c. ; or racemose,
consisting of short conical tubes, so proceeding
from the primary branches as to render the
ovary racemose or pinnated, such as they are
in many Neuroptera, Coleoptera, and Diptera.
The number of tubes composing each ovary
varies in different genera and species ; some-
times there are but two, at others four, five,
six, eight, or twelve, and in the more prolific
insects this number is much increased ; thus, in
Acrida viridissima there are thirty, and in the
hive-bee not fewer than a hundred and fifty
crcca in each ovarian packet. The number of
eggs will of course depend upon the number
and divisions of these ovarian tubes, and thus
while some insects only lay two, four, or six
eggs, others will produce sixty or seventy, arid
some gregarious insects a much greater num-
ber : thus the hive-bee will probably give birth
to many thousand young> and in the Termite
ant (Termes bellicosus) the fecundity of the
female is absolutely incalculable. This extra-
ordinary fertility renders indispensable certain
restrictions which we find imposed upon this
numerous class, tending materially to limit
their exce-sive multiplication. Thus, through^
out the whole race one generation only is pro-
duced from the same insect, the business of
reproduction being usually the termination of
its existence ; and in the most prolific tribes,
namely, those which live in society, as the Bee
and the Termite, one female only in each com-
munity is found to be fertile, the sexual organs
of all the rest remaining in a rudimentary or
undeveloped state, although capable of de-
velopement, should the destruction of the
queen render such a provision for the preserva-
tion of the race indispensably necessary. (See
IXSECTA.)

The uviductus or excretory canal common
to the ovarian tubes of the corresponding side
of the body, sometimes opens into the cloaca.

416

ORGANS OF GENERATION.

the eggs escaping by the anal passage ; but in
other cases, having joined that of the opposite
side, it terminates externally by a distinct
aperture ; near its extremity, however, it re-
ceives the auxiliary tubes or coeca, namely,
the spermotheca and the accessory glands.

The spermotheca is a membranous saccu-
lus of varying size and shape, regarded by
Herold and Malpighi as a receptacle in
which the seminal fluid of the male is de-
posited and retained, — an opinion which has
been sanctioned by subsequent anatomists ; it
is found only in such insects as deposit their
eggs in slow succession, and is presumed to
be a provision for the gradual fertilization of
the ova during their transit through the ovi-
duct. It is only upon this supposition that it
is possible to account for the impregnation of
some insects which are employed for a long
period in the business of oviposition, as is the
case, for instance, with the hive-bee, in which a
single coitus fertilizes all the eggs that are laid
for a space of two years, amounting some-
times to twenty or thirty thousand in number ;
and yet, in this case, it is difficult to conceive
how so small a reservoir, scarcely larger in-
deed than the head of a pin, can retain a
sufficiency of this fluid for such a purpose, a
difficulty which is scarcely lessened by admit-
ting the hypothesis of Dr. Ilaighton, who refers
the act of impregnation ralher to some pene-
trating effluvium or aura seminalis, which the
seminal liquor may emit during a long period,
than to actual contact between the semen arid
the ova.

The auxiliary glands (glandule succentu-
riatte), which are appended to the oviduct of
insects, perform an office which is by no means
satisfactorily determined; the most usual sup-
position is that they furnish some secretion
connected with the investment of the ova,
either for the completion of the shell, or, as is
more probably the case, for the purpose of
uniting them together by a tenacious mucus
into the long strings or masses in which they
are not unfrequently extruded. The structure
of these secerning ccjeca differs in different
insects, but will be found to conform in most
cases to one or other of the following types ; —

1. Most frequently they are merely elon-
gated tubes closed at one extremity while the
other opens into the oviduct.

2. In some cases the primary cceca give off
secondary branches.

3. In others, as in ffippobotca, they are
ramified tubes terminated by blind canals.

4. In Etater Murinus they present a very
remarkable structure, being composed of a
number of triangular capsules united by canals
arising from each angle until the terminal vessels
are reduced to simple cceca.

The ovipositor is the last part of the female
generative apparatus of insects which we have
to notice. This singular appendage to the
oviduct presents many varieties in its structure,
being adapted to the introduction of the ova into
certain localities either fitted for their matu-
ration, or, as is more frequently the case,
suited to the necessities of the larva after its

escape from the egg ; but a detailed account
of the forms which this organ assumes in dif-
ferent tribes would necessarily be incompatible
with the limits of this article, and the reader is
therefore referred for further information to the
article INSECTA.

Some insects are ovo-viviparous in a mo-
dified sense, and their offspring are produced
in the larva or even in the pupa state, the eggs
being hatched in the body of the parent, and
the young matured to a certain extent before
they are expelled. In such cases the oviducts
unite to form a capacious matrix, in which at
certain seasons the larvae are contained either
agglomerated in masses, or arranged parallel
with each other in flat bands. In this state
each larva is invested in a delicate membra-
nous bag. It is remarkable that all these larvae
are carnivorous, their office being to remove
putrifying flesh ; hence the necessity of their
being produced in such a state as immediately
to commence the work to which they are des-
tined.

Some Aphides, or plant-lice, are ovo-vivi-
parous in the early part of the year, but ovi-
parous as winter approaches, — a provision evi-
dently intended to secure the preservation of
the embryo during the inclement season, the
eggs remaining unhatched until the return of
spring.

The Aphides likewise in their mode of gene-
ration furnish the physiologist with one of the
most extraordinary anomalies met with in the
animal kingdom. From an accurate series of
observations, first instituted by Bonnet, and
subsequently confirmed by the indefatigable
Lyonnet, it is now received as an established
fact that the females of these insects have the
faculty of giving birth to young ones without
having had any intercourse with the other sex.
From the experiments of these naturalists it
appears to have been incontestably proved that
if a female Aphis at the moment of its birth
be rigorously kept from communication with
others of its species, it will, if supplied with
proper food, give birth to a brood of young
ones, and not only so, but if one of the off-
spring so produced be similarly treated, it like-
wise will prove fruitful, and so on to the fifth
generation, according to Bonnet, or even still
further, as Lyonnet afterwards ascertained.
Bonnet supposed, in explanation of this cir-
cumstance, that the Aphides are truly andro-
gynous, each being possessed both of ovige-
rous and impregnating organs ; yet this sup-
position is incompatible with the fact, that the
male insect is almost as common as the female,
and that the sexes copulate in the usual manner
during the termination of the summer season.
The only solution of this phenomenon appears
to be that one intercourse with the male suf-
fices for the impregnation of all the females
which in one season spring from the same
union. But the Aphides are not the only ex-
amples of this curious fact, as some of the
Branchiopod Crustaceans, as Daphnia pennata,
Mull. (Monoculus pulex, L.) are equally ca-
pable of producing fertile females through
several successive generations; nevertheless

ORGANS OF GENERATION.

417

both Bonnet and J urine observed that the fe-
male Aphides and Branchiopods that were
fertile without the usual intercourse of the
sexes were less fruitful than their mother, and
those of the last generation less so than the
first.

Arachnida. — In the Arachnida the gene-
rative system, both in the male and female,
is even more simple than that of insects. The
testes of the male are two in number, each
being an elongated membranous bag, closed at
one extremity, whilst the opposite is conti-
nuous with a slender and tortuous vas deferens,
the terminations of which are indicated ex-
ternally by two very small orifices distinguish-
able on the under surface of the abdomen near
its junction with the thorax. The apertures
through which the seminal fluid is discharged
are totally unprovided with any apparatus of
intromission or excitement; in lieu of which
many genera are provided with a singular sub-
stitute, or at least with an organ supposed by
some authors to be an exciting organ. This is
found at the extremity of the maxillary palpus,
but for a detailed account of its structure and
presumed functions the reader is referred to the
article ARACHNIDA.

The female organs of the Araneidae are
equally devoid of complication. The ovaries
are simple membranous bags, which occupy
when distended a considerable portion of the
abdomen, and are found to contain ova ag-
gregated together in considerable numbers.
From each of these ovigerous sacs a short
canal leads to an aperture situated near the
base of the abdomen, through which, when
mature, the ova are discharged. The most re-
markable circumstance observable in this form
of the generative system is the complete sepa-
ration which exists between the sexual organs
of the two sides of the body, which, both in
the male and female, not only do not com-
municate internally, but open upon the exterior
by distinct apertures; the insulation is, in fact,
so perfect that in some cases the eggs gene-
rated in the two ovaria are laid at distinct and
distant periods. According to Audebert some
spiders are rendered fertile for several years by
one intercourse with the male.

In the Scorpions the male generative ap-
paratus consists of a testis composed of nu-
merous tubes united together, so as to form a
series of loops, the secretion of which is dis-
charged externally by a double penis resembling
that of some reptiles, which is protruded
through a valvular aperture seen upon the
ventral surface of the thorax.

The female organs of the Scorpion, like
those of the male, are composed of loops of
tubes, uniting together at different points, and
when distended with ova resembling a neck-
lace of beads : they open by two canals, (vol. i.
Jig. 84, c, p. 205), at the same point which the
sexual aperture of the male has been seen to oc-
cupy, each having a small crecum or succentu-
riate gland appended near its termination. The
eggs of Scorpions are hatched in the oviducts,
and the progress of the developement of the
embryo maybe easily distinguished through the

transparent coats of the ovum? resembling most
accurately that observed by lierold in the evo-
lution of the young spiders, figures of which
are given elsewhere.*

Crustacea. — As in the Arachnida, the gene-
rative system of Crustaceans is for the most
part double, the parts belonging to the two
sides of the body being generally completely
distinct from each other, not only internally
but at their termination. In the higher orders
the testes of the male and the ovaries of the
other sex are found to be situated in the dorsal
region of the thorax ; in both cases these
organs appear at first sight to be of a dense
glandular structure, but, on examination, are
found to be essentially composed of tubular
convolutions. In both the male and the fe-
male, the excretory canals are simple tubes,
which, after some convolutions, terminate in the
male by prominent apertures, found upon the
coxal portion of the fifth or posterior pair of
true legs, and in the female by similar open-
ings at the base of the third pair.

As in Insects, the female organs have in
many genera a sacculated appendage, or copu-
latory pouch as it is termed, which is, in fact,
analogous in function to the spermotheca of
insects, serving as a reservoir in which the
male semen is detained for the purpose of im-
pregnating the eggs as they successively escape
from the body. After their exclusion from the
oviduct the eggs of Crustaceans are generally
carried about by the female. In the Decapoda
they are appended by a glutinous material to
the false feet situated under the tail. In the
Isopodn and others they are retained in recep-
tacles formed by scales placed under the ab-
domen, whilst in the Entoraostracous forms,
as well as in many Epizoa approximating the
Crustacea in structure, a remarkable provision
is made for perfecting the eggs external to the
bodies of these minute creatures, the females
being provided with one or two membranous
sacs appended to the posterior part of the
abdomen, into which the oviducts open, and in
which the ova are retained until they arrive at
maturity.

Mollusca. — Several of the more perfectly
organised Mollusca come likewise under this
division of our subject. Such are the Pectini-
branchiate Gasteropoda, in which the structure
of the generative apparatus is sufficiently sim-
ple. In the male a large testis, composed of
racemose follicles, shares with the liver the
convolutions of the shell : from this the seminal
secretion passes by a long and tortuous vas
deferens to the extremity of the penis, which
is in these creatures an extensile and veiy
muscular organ, situated on the right side of
the neck, and not unfrequently of enormous
size when compared with the bulk of the
animal.

The ovarium in the female Pectinibranchiate
Gasteropods corresponds in position with the
male testis; the oviduct arising from it is
capacious, glandular, and convoluted, serving
in some genera, as in Turbo, as a receptacle

* Vide Article ARACHNIDA.

418

ORGANS OF GENERATION.

in which the eggs are frequently hatched.
Near its termination the oviduct communicates
with a glandular apparatus supposed to furnish
the viscid envelope by means of which the
eggs are generally agglutinated together.

In the Cephalopoda likewise, as in the Mol-
lusca generally, the generative system is single.
In this class the testis is an azygos viscus,
composed of elongated branched coeca, in-
closed in a membranous capsule, into which
apparently the seminal fluid escapes. The vas
deferens is narrow, and convoluted at first,
but afterwards it enlarges and becomes mus-
cular in its structure, serving doubtless as an
instrument for the expulsion of the semen.
This seminal canal receives the duct of a large
glandular mass, and dilating into a pouch,
ultimately terminates at the root of a rudi-
mentary penis, apparently adapted to intro-
mission, although it has not yet been ascer-
tained whether actual copulation takes place,
or whether the ova are fecundated after their
extrusion, as is the case with fishes.

In the female Cephalopoda the ovarium, like
the testis of the male, is azygos, and placed
in the same situation. Its structure is remark-
able, being a strong capsule, to the interior of
which adheres a cluster of vesicular bodies
denominated ovisacs, from which, at certain
seasons, the ova escape. From the ovarian
capsule arises the oviduct; this is in some
instances a single tube, but in others divides
into two canals ; in either case, before its ter-
mination behind the base of the syphon, it
passes through a thick laminated glandular
structure, which secretes the dense coriaceous
investment enclosing the ova, and the material
which unites them into the racemose clusters in
which they are usually found.

Vertebrata Ovipara. — In the vertebrate divi-
sion of the animal kingdom the generative
system presents great varieties, although from
the lower to the higher orders we may distinctly
trace a series of gradations which, in a physio-
logical point of view, are of the highest interest.

In Fishes the ovaria are formed upon two
distinct types. In the osseous fishes they are
for the most part two large membranous sacs,
which, when distended, occupy a considerable
share of the abdominal cavity ; these open by a
short canal in the vicinity of the anus. In these
capacious sacs the ova are developed : they are
found united together by a delicate membrane,
and attached in numerous festoons to the walls
of the ovary until sufficiently mature for expul-
sion, when, breaking loose from their con-
nexions, they escape into the ovarian cavity
and are discharged through its excretory duct.
In this case the Fallopian tubes found in other
vertebrata do not exist, the oviduct being pro-
longed from the ovary itself in the same manner
as the duct of a secreting gland, and the whole
apparatus, in fact, strongly resembles what we
have found in the Conchifera and other Mol-
lusks, the great distinction consisting in the
necessity which here exists for the impregnation
of the ova by the agency of the male. The
fecundation of the eggs is effected externally,
after their expulsion, and, in fact, it is the

spawn rather than the female, which forms the
object of the pursuit of the male, as in most
instances both sexes appear as careless con-
cerning each other as they are of the off-
spring which they produce. The ova, which
are incalculably numerous, are deposited in
shallow water, where they may receive the
influence of the solar beams, and in this situa-
tion are eagerly sought after by the males
destined to make them fertile ; these, urged
apparently by the necessity of ridding them-
selves of an inconvenient load, discharge the
secretion of their voluminous testes into the
water, which, becoming diffused in the vicinity
of the ova, is sufficient for their impregnation.
In the males of this class of fishes the tesles
are of enormous size, equalling in bulk the
ovaria of the other sex, and occupying a corres-
ponding situation in the abdomen. Each testis
is made up of a congeries of seminal canals,
which, when inflated through the excretory
duct, distend the whole organ. The seminal
tubes are in most instances arranged parallel to
each other, and are closed at one extremity
while the other terminates in the common canal
or vas deferens, which in every respect resem-
bles the oviduct of the female.

This is the most usual structure of the male
apparatus of fishes, but in some, as in the Shad
(Clupea Alosa), the seminiferous tubes form
innumerable ramifications and anastomoses in
the substance of the testicle, easily discernible
by the naked eye ; and from the plexus thus
produced coecal tubes are prolonged to the sur-
face of the organ, where they terminate by
rounded extremities, giving the whole viscus,
externally, a granulated appearance. (Fig-
204.)

A few of the osseous fishes form remarkable
exceptions to the usual mode of impregnation,
the ova of the female being in such fecundated
prior to their expulsion by actual copulation
with the male ; and in some rare instances, as
in the Blennius viviparus, the young are even
produced alive, the ova being retained within
the oviduct until they are hatched. In such
cases the termination of the vas deferens swells
into an external projection resembling a rudi-
mentary penis, and, indeed, actually performing
the office of an organ of intromission.

In the more highly organized cartilaginous
fishes, and even in some osseous genera, the
structure of the generative system is entirely
different, commencing that type which charac-
terizes tiie reproductive organs of all the other
vertebrate classes. In these the ovaria are not
hollow sacs which have their cavity prolonged
to the exterior of the body, but the ova are
developed between layers of membrane sus-
pended in the abdomen, which are unprovided
with any canal immediately communicating
with them. Such are the ovaria of the Eel
and the Lamprey, which are formed of nume-
rous festoons of delicate and vascular membrane
suspended in front of the spine. The ova pro-
duced between these membranous layers when
mature break loose into the cavity of the
abdomen, and are discharged through a simple
orifice in the neighbourhood of the anus. In

ORGANS OF GENERATION.

419

Fig. 204.

Structure of the Testes m Clupea Alosa.

this arrangement we have, therefore, the simplest
form of the isolated ovaria of Reptiles, Birds,
and Mammalia, in all of which the ova escape
from the surface of the ovary, not from its
interior; and in the orifice through which the
eggs are ultimately expelled from the abdomen
we see the first rudiment of a Fallopian tube.
In the Lamprey this orifice is prolonged into
a short canal, and in Rays and Sharks assumes
the form of an oviduct with which we shall
afterwards see the Fallopian tubes of Mammals
are identical; for whatever the complication
which it afterwards assumes, the oviduct or
Fallopian tube (for the two are the same in
function) only receives the ova after their escape
into the cavity of the abdomen to facilitate
their ultimate expulsion. In Kays and Sharks
the oviduct is double, commencing, however,
by a fimbriated aperture common to both,
which receives the eggs from the ovaria ; each
oviduct is at first narrow and membranous,
having its lining membrane longitudinally
plicated, but before its termination the walls
suddenly increase in thickness, developing in
their interior a large gland destined to furnish
the horny covering which invests the eggs of
these creatures. Beyond the gland the oviduct
expands into a capacious bag, which communi-
cates with the cloaca.

In this class of fishes the testis, like the
ovary, is not hollow. In the Eel and Lamprey
the secretion of the testis escapes from the
external surface of the organ into the abdomi-
nal cavity, whence, like the eggs in the females
of the same tribes, it is expelled through a
simple orifice provided for its egress. In these
creatures the testis and ovarium are so entirely
similar that they have been confounded by
authors, the secreting granules in the one sex
and the ova in the other being both disposed

in regular laminae, and only differing inas-
much as the testicular granules are smaller
than the mature ova.

The structure of the testis in Rays and
Sharks is peculiar, these animals being appa-
rently provided with both the kinds of testis
above described. Each testicle consists of two
portions quite detached from each other; the
one is formed of an aggregation of globular
masses as large as peas, from which no excre-
tory duct has been found to issue ; the other is
made up of convoluted canals, which, gradually
uniting together, terminate in a capacious tube.
The tuberculated mass has been described as
the testis, while the convoluted tubes of the
other portion were regarded as an epididymus,
whence the vas deferens took its origin. There
is, however, no communication between the
granular part and that whence the vas deferens
issues ; it is, therefore, probable that the former
is analogous to the solid testis of the Eel and
Lamprey, pouring its secretion into the abdo-
minal cavity, whence it is emitted through the
apertures well known to communicate in these
creatures between the peritoneal bag and the
exterior, while the latter is identical with the
usual form of the testis in osseous fishes.

TheBatrachian Reptiles in their mode of gene-
ration, as well in so many other points of their
economy, form the transition from the branchi-
ferous to the pulmonary forms of theVertebrata,
and hence the study of their sexual organs is ex-
ceedingly interesting. The ovaria of these ani-
mals in their entire organization resemble those
of the Lamprey. Their size, however, is much in-
ferior, and the whole organ exhibits a more con-
centrated arrangement. The vascular membrane
which forms each ovary is arranged in large
folds on the sides of the spine, and the ova
are deposited in great numbers between the
lamellae of which it consists. The oviducts
are long and tortuous, each commencing by a
fimbriated aperture which is found to be situated
at the side of the pericardium, and so bound
down in that position by its peritoneal attach-
ments that when the interval which separates this
point from the ovaria is considered, it is difficult
to conceive how the ova, when dislodged from
the nidus in which they were formed, can be
brought into the oviduct ; the only supposition,
in fact, which will account for it is, that the
eggs break loose into the abdominal cavity and
thus make their way to the extremities of the
oviducts. Before terminating in the cloaca
the oviducts expand into capacious recepta-
cles, in which the ova are collected prior to
their expulsion, and glued together by a glairy
secretion into masses which distend the whole
of the abdomen.

The ovaria of the Salamanders resemble
those of the frog, as do the oviducts, but the
membranous sacs which retain the ova are less
considerable than in the Anourous Batrachia :
the same observations apply to the perenni-
branchiate orders.

The structure of the testis in frogs is almost
the same as that of the same organ in the
cuttle-fish. If the investing tunic be removed,
the whole substance of the organ appears com-
posed of globules; but if these are gently sepa-

420

ORGANS OF GENERATION.

rated, they are found to be merely the blind
terminations of as many seminal tubes which
run from the centre to the circumference of the
testicle. The seminiferous ducts arising from

Fig. 205.

Testis of Frog.

these perforate the investing tunic of the kidney,
upon which the testis is placed, and, according
to Swammerdam, terminate in the ureters,
which thus perform likewise the office of the
vas deferens.

We have carefully repeated Swammerdam's
dissection of these parts, which are represented
at/g. 206.

Fig. 206.

Generative organs of Male Frog.

a, Cloaca ; b, opening of genito-urinary canal ;
, opening of bladder into cloaca ; d, rectum ;
, bladder ; f, testes, that of the right side in

'

situ i g, kidneys ; h, seminiferous tubes ; ;',
tube serving both as ureter and vas deferens ;
k, vesiculae seminalcs j lt fatty appendages to
the kidney. ,

In other Amphibia the organization of the
testis is essentially the same, but the seminal
coeca, owing to their greater length, are tortuous
and convoluted.

The ova are impregnated in exitu by the
aspersion of the seminal secretion of the male,
who, firmly fixed upon the back of his mate,
assists by his embraces the expulsion of the
gelatinous masses in which the eggs are im-

bedded. No organ of intromission, therefore,
is required, and the generative ducts, both in
the male and female, open by simple apertures
into the cloaca. Nevertheless, in a few instances
internal impregnation is effected; such is the
case with Triton, Laurent, in which, although
no copulation takes place, the male fluid dif-
fused through the surrounding water finds its
way into the genitals of the female in sufficient
quantities to secure fecundation. Moreover,
in the Salamander ( ' Lacerta Salamandra) an
intromission is accomplished, the male pos-
sessing a rudimentary organ for that purpose ;
in this latter case the eggs are even hatched in
the oviduct and the young produced in the
tadpole state.

In the other reptiles the structure and
arrangement of the generative organs is very
similar; the same organization, in fact, exists
through the whole class with slight modifica-
tions adapted to the different forms or habits of
different orders.

Fig. 207.

The testes are invariably double, placed
symmetrically on the two sides of the body,
and attached by membranous connexions to the
vertebral column. On unravelling their inter-
nal structure they are found to consist entirely
of blind tubes enclosed in a membranous cap-
sule ; these seminiferous canals are much longer
than in the amphibious tribes, and, conse-
quently, present a tortuous arrangement, readily
seen through the transparent covering of the
testes. (Fig. 207.) From these tubes a variable
number of efferent canals proceed, which, after
remaining for a short distance enclosed in a pro-
longation of the tunics of the testicle, unite into
a vas deferens, which is prolonged on each side
to the cloaca, and there terminates at the root of
the rudimentary penis.

In the higher Reptilia impregnation is always
effected internally, and the males are conse-
quently provided with an organ of excitement,
differing much in form, but invariably imper-
forate, being merely grooved upon its surface
by a channel, along which the semen flows
into the cloaca of the female, but without any
provision for its forcible expulsion.

This kind of penis consists entirely of the
corpora cavemosa, arising by two crura,

ORGANS OF GENERATION,

421

which unite intimately along the upper aspect
of the organ, but leave inferiorly a deep fissure
which is continued to the extremity. In the
Chelonia this organ of excitement is very large,
and terminates in a single point, but in many
Saurian and Ophidian species its extremity is
birkl, each division being covered with sharp
and recurved spines, an arrangement which, in
creatures so deficient in organs of prehension,
is evidently adapted to ensure efficient copu-
lation.

In the females of these reptiles the structure
of the ovaria is interesting, gradually leading us
from the folds of vascular membrane, between
which the numerous eggs of the Batrachia are
generated, to the form which they present in
Birds. Each ovary assumes a racemose ap-
pearance, and consists of a number of ova in
various states of perfection, which are loosely
attached to the sides of the vertebral column by
folds of peritoneum. Their structure, however,
is essentially that which has been already de-
scribed, and the ova, when matured between
the vascular laminae of the ovarian investments,
escape, as in frogs, from the surface of these
viscera by a laceration of the investing mem-
brane, and would break loose into the abdo-
minal cavity did not the more perfect develope-
ment of the oviducts, which here have their
patulous extremities so disposed that they can
grasp the ovaria during excitement, prevent such
an occurrence, by receiving the germs imme-
diately from the ruptured ovary. The oviducts
are two in number, membranous at first, but
glandular as they approach their termination
in the cloaca. In these the eggs receive an
albuminous investment which they absorb in
the first portion of the canal, and prior to their
expulsion are furnished with a coriaceous or cal-
careous covering produced from the thicker
portion of the oviferous tube.

The females of the Chelonia have a clitoris,
or rudiment of the male penis, which is in a
similar manner provided with muscles for its
retraction into the cloaca after extrusion. In
other Reptiles the clitoris is deficient.

Birds form a remarkable exception to the
usual arrangement of the internal sexual organs
in oviparous vertebrata,the ovarium and oviduct
being single throughout the class, an organi-
zation which is evidently in relation with that
lightness and activity essential to their habits.
This deviation from the usual type, however,
is only apparent, arising from the non-develop-
ment of the ovary and its duct on one side of
the body, although both exist in a rudimentaiy
state.

The ovarium, as in Reptiles, is racemose,
consisting of ova in different stages of growth,
each enclosed in a vascular membrane, which
forms a pedicle attaching it to the general
cluster, and is ruptured by the escape of the
germ enclosed within it. The oviduct is short in
comparison with that of many reptiles, and the
structure of its lining membrane indicates the
offices performed by different portions of the
canal, being smooth and vascular in its upper
portion, where the yolk receives its albuminous
covering, but becoming villous and plicated
where it secretes the shell.

Male birds, like reptiles, are furnished with
two testes, which, from their comparatively in-
significant size, do not materially interfere with
the bulk of the viscera; yet even these only as-
sume their full proportions at stated times,
namely, at that period of the year when their
office is required.

The lestes are constantly situated in the ab-
dominal cavity immediately behind the lungs
and under the anterior extremity of the kidney :
as in all cases, they consist of sperm-secreting
tubes, but of such extreme tenuity that their
diameter was estimated by Miiller as not
greater than the 0-00528 of a Parisian inch.
These canals are enclosed in a proper capsule,
which sends septa into the interior of the organ ;
they unite to form a slightly flexuous vas defe-
rens, which accompanies the ureter of the cor-
responding side. The vasa deferentia termi-
nate by separate orifices in the cloacal cavity
near the root of the rudimentary penis when
such exists, but even in its most perfect forms
the male organ is merely an instrument serv-
ing for the conveyance of the seminal liquor
along a groove seen upon its surface, there
being as yet no corpus spongiosum or inclosed
urethra as in the Mammiferous classes, adapted
to an efficient injection of the semen into the
female parts, nor any auxiliary secretions sub-
servient to the same purpose. In the females
of those genera in which the penis is most de-
veloped, a clitoris is found to occupy a similar
position.

The Mammalia differ remarkably from the
other vertebrate classes in the elaborate deve-
lopement of the sexual organs in both sexes.
The increased complication of these parts is attri-
butable in the male to the necessity for a much
more efficient intromission of the spermatic
secretions during coitus, and in the female to
the superadded function of gestation which
characterizes the class.

On comparing the male organs of Mammi-
fera with those of the oviparous vertebrata,
several circumstances demand our notice, the
most striking of which is the separation of the
canals provided for excretion into two distinct
systems, each terminating externally by an
appropriate orifice, thus detaching entirely the
digestive emunctory from the genito-urinary
apparatus, which hitherto we have found to dis-
charge themselves by one common orifice com-
municating with a cloacal cavity. With one
interesting exception furnished by the Mono-
tremata, such a separation exists throughout all
the Mammiferous orders. Internally a still
further isolation is evident in the separation of
the urinary and generative organs by the pro-
vision of a urinary bladder, in which the secre-
tion of the kidneys is stored up until its expul-
sion becomes necessary ; the same excretory
canal, however, is still common to both these
systems. In the ovipara the penis was merely
furrowed with a sulcus, along which the semen
trickled during the union of the sexes without
being impelled by any expulsive apparatus ;
but in the class of which we are now speaking
the urethral canal becomes surrounded by vas-
cular erectile tissue, forming a complete tube
through which the seminal liquor is powerfully

422

ORGANS OF GENERATION.

ejaculated during copulation by a muscular
arrangement provided for that purpose ; and in
the last place the emission of the fecundating
fluid is further provided for by the addition of
secondary secretions, which from augmenting
its quantity facilitates its ejection.

We shall proceed to speak of these circum-
stances seriatim, examining first, the structure
and position of the testis and its duct; secondly,
auxiliary glands which add their secretions to
the seminal liquor; thirdly, the structure of the
penis, and arrangement of the organs of intro-
mission.

We have found in all the classes of verte-
brata of which we have hitherto treated, that
the testes consisted essentially of blind tubes.
In Frogs these sperm-secreting canals were ex-
ceedingly short; in other Amphibia they become
elongated and flexuous. In Reptiles their
length and convolution was still further in-
creased, until at length in Birds and Mamma-
lia their length is so great, and their delicacy
so excessive, that they are with difficulty unra-
velled. In all animals the terminations of the
seminal tubes are found to be closed, neither is
any increase or diminution perceptible in the
diameter of one of these vessels throughout its
whole course. Another circumstance which,
with one or two exceptions, is common to all
Mammals, is that they never ramify or divide.*

Mammalia differ much amongst each other
as regards the length, number, convolutions,
and general arrange m en t of these secerning
vessels of the testis. In the Ass they are very
delicate; of greater diameter in the Cynoce-
phalus and larger Carnivora, as well as in the
Hog and Rhinoceros. They are very large in
the Glires, and in Sciurus their diameter
reaches -0-01453 inch (Paris), whilst in the
Hedgehog they are only 0'00970 inch.

The tenuity of the walls of these seminal
vessels is extreme, and scarcely applicable by
the micrometer ; they are united together by a
most delicate tissue of capillary bloodvessels,
serving to imbue them with that blood from
which the semen is separated, which when se-
creted accumulates in the cavities of these tubes
in readiness for expulsion.

The testes are very variously situated in the
adult state of different mammals. Sometimes
they are contained within the abdominal cavity,
attached on each side of the spinal column by
folds of the peritoneum, as in the ovipara ; at
other times they descend into the skin of the
groin through the inguinal canal, and not un-
frequently are contained in a scrotal pouch
formed by the integument behind the pubic
arch; and in the Marsupial division, which,
when describing the female sexual organs, we
shall find to constitute a distinct type of the
generative system, they are suspended in front
of the pelvis.

The excretory duct of each testis or vas de-
ferens is formed by the junction of the seminal
canals of the testis ; it is at first much convo-
luted, forming a mass appended to the testicle,
denominated the epididymus; and whatever

In Sciurus they have been observed to divide
dichotomously.

may be the position of the testicle, it runs to
discharge itself into the canal of the urethra
near the commencement of that tube.

The prostate gland is a secreting body of pe-
culiar structure, which, in man, embraces the
neck of the bladder, and opens by ten or twelve
ducts into the urethra near its commencement.
It is very constant in its existence, being found
in all orders of Mammalia, excepting, perhaps,
the greater number of the Rodentia, the Mole,
and the Hedgehog, in which it is apparently
replaced by secerning organs of a widely dif-
ferent structure; otherwise, the internal organi-
zation of this gland is nearly the same in all
animals that possess it, consisting essentially
of cells, each of which is subdivided into others
of extreme minuteness. From these cells the
excretory ducts take their rise, and the whole
organ may be readily inflated by forcing air into
the canals which issue from it : the whole is
enclosed in a dense fibrous capsule. In some
animals, as the Elephant and Solipeds, the
prostate is double or even quadruple, and in
this case the centre of each portion has within
it a large cavity which communicates with the
smaller cells, and gives origin to the excretory
tube.

Coivper's glands. — These glands in the hu-
man subject are two very small bodies situated
behind the bulb of the urethra, which furnish
minute canals, opening obliquely into the urino-
generative canal near its posterior portion ; but
minute as they are in man, they are found in
other creatures to be much more voluminous,
not unfrequently equalling the prostate in size,
and in some cases, especially in the Marsupial
division, they are increased in number; thus
in the Opossums and Kangaroo-rat there are
four, while in the Wombat (Phascolomys),
the Kangaroo, and others, even six are found :
nevertheless in most of the Carnivora, except
the Felidse and Hyenas, and in the greater
number of Ruminants, Solipeds, Amphibia,
and Cetacea, they are deficient.

The internal structure of Cowper's glands
varies. In man and many others they are
composed of simple follicles ; in other cases,
as in Sciurus, the Marmot and the Hog, they
consist of conical sacculi, which exhibit in-
ternally a cellular appearance. In the Beaver
(Cantor Fiber) their texture is spongy, being
formed of large cells, divided by septa into
smaller ones of extreme minuteness ; those of
the Mole are similarly constructed. In Vi-
verra Zibetha, the feline tribes and the Hyena,
they are made up of separate lobules; and
in the Ichneumon these glands are composed
of vesicles united by a common duct. In
the Hedgehog ( Erinaceus Europaus) they are
found in a very singular position, being partly
situated beneath the rami of the pubis and
ischium, and partly beneath the skin on the
inner side of the thigh, being so remote from
the other glands that their existence was over-
looked by Cuvier. Each gland consists of
pyramidal lobules, which, by their apices,
give rise to the excretory canals,

In some of the Marsupiata their minute
structure resembles what is found in the Hedge-
hog; and each of them is surrounded by a

ORGANS OF GENERATION.

423

powerful muscular sheath, calculated to en-
sure the expulsion of the fluid which they
elaborate.

The most remarkable arrangement of Cow-
per's glands is seen in the Ichneumon ( Her-
pestes Ichneumon, Illiger): in this animal they
are very large and occupy their usual position,
being invested with a strong muscular coat;
but their excretory ducts, instead of termi-
nating as usual in the bulbous portion of the
urethra, are prolonged beneath the penis nearly
to the extremity of that organ, where they
open into a cul-de-sac common to them and
the canal of the urethra.

Accessory vesicles. — These are auxiliary
glands, which pour their secretions into the
canal of the urethra. They appear, when
present, to take the place of the prostate,
being only found where that organ is deficient,
and accordingly, although of a totally different
structure from that body, they have been called
prostates by various authors. They are usually
packets of membranous cceca, more or less ra-
mified, and in the season of sexual excitement
are filled with a fluid resembling that contained
in the vesiculae seminales. These organs exist
in all Rodents except Squirrels, Marmots, and
Hares, and also in the Hedgehog and the
Mole, but have not been found in any other
mammalia. They are invariably composed
of intestinules or branched coeca, arranged in
packets, the number of which varies much.
Thus in the Mole there are five such bundles,
forming a mass of ramified tubes larger than
the bladder ; in the Hedgehog there are four,
and in Cricetus vulgaris and Dasyprocta
Aguti two fasciculi.

But besides the secreting structures above
enumerated as forming the ordinary appendages
to the male generative system of Mammifers,
additional ones are occasionally found, placed
out of the positions in which the succenturiate
glands usually exist. Thus in Solipeds a long
coecum containing a glairy fluid is placed be-
tween the insertions of the vasa deferentia,
which communicates with the urethra by an
appropriate orifice ; and in Cricetus and many
of the JMuridtE the ends of the deferent canals
before their termination are provided with
bunches of small glandular follicles, which in
the former resemble small bunches of grapes.

Fig. 208.

The annexed figure, (fig. 208,) representing
the male generative viscera of the Rat ( Mus
Ruttus) exhibits an example of the greatest com-
plication of these parts, and will serve to illus-
trate the situation of the organs above described.
A represents the bladder turned forwards, B the
rectum, and C the testis of the left side. The
succenturiate glands here found are «, a, the
vesicu/te seminales ; 6, the anterior fasciculus of
the accessory vesicles or anterior prostate of
some authors, which on the opposite side is un-
ravelled to display the cceca which compose it ;
c, the middle prostatic coeca; d, the anterior
prostatic coeca. These all communicate with
the urethra, and in addition to these we have
on each side the racemose bunch of follicles (e)
which is appended to the termination of the
vas deferens (./").

Structure of the penis. — The great difference
between the penis of Mammifers and that which
has been described as existing in the oviparous
vertebrata, consists in theinclosure of the canal
of the urethra, which is no longer a simple
groove formed by the junction of the corpora
cavemosa, but becomes surrounded with a cy-
linder of erectile tissue usually denominated
the corpus spongiosnm urethra. The corpus
cavernosum, which generally forms the great
bulk of the organ, arises by two crura, which are
firmly attached to the rami of the ischium in
the males of all placental Mammalia; and even
in the Cetacea, where there is no pelvis, two
bones placed on each side of the corpus caver-
nosum give a support to the penis, which is
attached to them by fibrous ligaments; never-
theless, in the Marsupiata the crura of the
corpus cavernosum are quite free, or only
loosely attached to the ischiadic bones by
the muscular sheaths in which they are en-
veloped. The crura of the corpora cavernosa
unite to form the body of the penis, their
union being generally marked by a strong
septum, which more or less completely divides
the organ into two lateral halves. In some
animals, as in the Dog, this septum is very
distinct ; but in other cases, especially in many
of the Plantigrade Carnivora and in most of the
Pachydermatous and Cetaceous tribes such a
partition is entirely wanting; in such cases the
fibrous lamellae, which arise from the dense
capsule surrounding this portion of the penis,
and traverse the vascular tissue which is con-
tained in its interior, unite at a central part in
a kind of cord formed by their union. In
some animals the organ is supported by a bone
developed in its interior: this arrangement
exists in the Quadnmuma, Cheiroptera, the
Plantigrade and Digitigrade Carnivora (ex-
cept the Hyaena), and in the Rodentia, also in
Seals and Cetaceans. In a few instances it is
so large as to form a large portion of the penis,
as in Whales ; in others, as in many Carnivora
and Rodentia, it is extremely small, but what-
ever its form or size it is invariably found in-
timately connected with the corpus caverno-
sum.

The urethra, as in man, consists of a mus-
cular and of a vascular portion, the former
receiving the ducts of the succenturiate and

424

GENERATION.

seminal glands, the latter embedded in the
erectile tissue of the corpus spongiosum. The
muscular portion does not always join the vas-
cular part in a straight line ; but, on the con-
trary, in some animals, as in Ruminants gene-
rally and in the Boar, the former opens by an
orifice perforated in the upper wall of the
latter, at a little distance from its commence-
ment, so that a cul-de-sac is left excavated in
the bulb of the urethra or commencement of
the spongy portion, in which the fluids poured
into the muscular part are mixed with the se-
cretion of Cowper's glands, which enters the
sides of the excavation.

In Squirrels and Marmots a similar cul-de-
sac exists, which only receives the secretion of
Cowper's glands, arid is continued forwards
as a narrow tube surrounded by vascular tissue,
beneath the urethra, as far as the middle of the
penis, where the two canals unite.

The course of the urethra in the great Kan-
garoo ( Macropus major) is peculiar ; instead
of passing, as is usually the case, beneath the
corpus cavernosum, it is inclosed in a canal
passing through the centre of the penis, from
which it only emerges at the extremity of the
glans ; owing to this arrangement, the spongy
investment of the canal is in this animal con-
founded with the vascular tissue of the corpus
cavernosum.

In others of the Marsupiata the corpus spon-
giosum, like the cavernous body, arises by two
crura, which are quite unattached, each being
invested with a strong muscular sheath, and
even in some placental Mammals, as the Water-
rat and the Camel, rudiments of this division
are distinguishable.

The glans penis, or extremity of the intro-
mittent organ, presents many modifications in
form and in the nature of its surface. It is
frequently smooth and highly sensible, as in
man, being only covered by a delicate skin ;
yet in other instances, as in the feline Carni-
vora, it is armed with stiff recurved bristles ;
sometimes the armature represents horny scales
or strong spines, and in not a few genera we
find horny serrated plates projecting from its
surface; and, as though these formidable saws
were insufficient, they are occasionally com-
bined with horny prongs protruded from the
extremity of the penis during its erection.
These last appendages are found in various
families of the Rodentia, as in Guinea-pigs
and Agoutis. The limits of this article will
not permit us to expatiate further on this part
of our subject; we must therefore refer the
reader for a description of the various forms of
the penis and of the muscles belonging to that
organ to the articles which treat of the Mam-
miferous orders individually.

The female Mammalia exhibit in their gene-
rative system a beautiful gradation of struc-
ture. They naturally divide themselves in
conformity with their mode of gestation into
two classes, viz. the Ovo-vivipara or Marsu-
piata, and the Vivipara, properly so called,
comprising the placental orders.

The former division approximates in every
particular to the oviparous type of structure :

the ovaria are racemose, as in birds; the ovi-
ducts, which now assume the name of uteri, are
still double, opening by distinct orifices into
the vagina, which also is not unfrequently di-
vided. But the great feature which distin-
guishes the ovo-viviparous mammals is the
peculiar apparatus in which gestation is com •
pleted, the embryo being expelled from the
uterus at a very early period, without ever con-
tracting any vascular connexion with that organ,
to be lodged in a marsupium or pouch con-
nected with the abdomen of the mother, in
which the nipples are contained. In this situ-
ation it becomes attached by its mouth to one
of the teats, and thus derives from the mam-
mary secretion the nourishment essential to its
growth. — See MARSUPIATA.

In the Placental division gestation is com-
pleted within the uterine cavity by the deve-
lopment of a vascular mass of different con-
struction in different classes, called the Pla-
centa. The ovaria here gradually lose their
racemose appearance, and are converted into
small and solid masses, in which the ova or
Graafian vesicles are evolved. The uterus, at
first completely divided, as in some of the
Rodentia, in which the two cornua open se-
parately into a single vaginal canal, by degrees
unites, and by a progressive coalescence attains
that concentration most perfectly exhibited in
the human female.

To enter more largely into details connected
with the generative organs of the Mammiferous
classes would needlessly swell the bulk of this
article, in which our object has been to lay
before the reader a connected view of the mo-
difications met with in the reproductive system
throughout the animal kingdom, and thus to
connect with each other the numerous facts
relating to this subject which are elsewhere
more minutely recorded in this work.

For the anatomy of the Organs of Generation in
Man, see PENIS, PROSTATE, TESTIS, VESICULJE

SEMINALES.

(T. Rymer Jones.)

GENERATION (in Physiology) generatio;
Fr. generation; Germ. Zeugung; Ital. gene-
razione ;) is the process by which the young
of living bodies are produced, and their spe-
cies continued. In common language the
term is frequently confined to the mere act of
union of the sexes of animals ; but in general
and animal physiology it is generally employed
in the more extended signification given to it
in the following article, viz. to denote the assem-
blage of all the functions of animals concerned
in the formation of their young, and as syno-
nymous, therefore, with the function of Repro-
duction.

In directing our attention to the mode in
which the function of reproduction is effected
in various classes of animals, so many striking
differences present themselves, that we find it
difficult if not impossible to point out any
general circumstances in respect to which they
all agree. Some animals, for example, are
propagated by the division of their whole
bodies into pieces, each of which by a pecu-

GENERATION.

425

liar change becomes an independent individual
entering upon a new life. Others arise like
the parts of a tree by buds which remain for
a time attached to the parent stem, and being
afterwards separated from it assume an inde-
pendent existence. A third class of animals
have the power of forming and throwing off
from their bodies a small portion of organized
matter, which, though at the time of its sepa-
ration from the parent, not resembling it either
in form or organization, is yet possessed of the
power of living for itselfj and, after passing
through a variety of successive changes of
growth and evolution, of at last acquiring the
exact semblance of the parent by which it was
produced. In a fourth and last class, com-
prehending much the greatest number of ani-
mals, the function of reproduction involves a
greater complication of vital processes than in
the three other classes above alluded to. The
union of two individuals of different sex be-
comes necessary, and the young owe their
origin to the evolution of a more complex
organized structure termed the egg, which is
formed in and separated from the body of the
female parent, and is the product of the union
of the male and female of all animals in which
the distinction of sex exists. The ovum or egg
is most familiarly known to us in the eggs of
domestic birds, to which the product of sexual
union in all animals belonging to this fourth
class bears a strict analogy in every essential
particular.

It may be stated as a general fact, that the
reproductive function involves a greater num-
ber of vital processes in the higher and more
complicated than in the lower and simpler
kinds of animals. Yet there are exceptions
to this rule, and we do not always trace a
correspondence between the degree of com-
plication of the generative process of any
animal and the place which that animal holds
in the scale of being ; for there are some tribes
of animals which are propagated in more than
one of the ways above mentioned, and there
are some, to which, from the simplicity of their
other functions and organization, a low place
in the zoological scale has been assigned, and
which nevertheless resemble the higher animals
in respect to their mode of reproduction.

A veiy superficial view, however, of the vari-
eties of the form obvious in the reproductive
process of different animals demonstrates the
importance of the reproductive functions in the
economy of life, as it points out the intimate
relation which these functions bear to the
habits, mode of life, and organization of each
animal, and shews the infinite care and fore-
sight with which nature, in every variety of
circumstance, has provided for the regular and
undisturbed performance of those acts by
which the species of organize I beings are con-
tinued from age to age, in an undeviating suc-
cession of generations. These facts also fully
justify our regarding, along with Cuvier, the
reproductive function as constituting one of
the fundamental divisions in a classification of
the processes of the animal economy.

\\ hile, therefore, the principal object of the

VOL. If.

present article is to describe the process of
generation in Man and the higher Vertebrated
animals, it will be necessary and proper for us
to allude also to the reproductive function as
it is performed in all the various members of
the animal series; for in this, as in other de-
partments of Physiology, the more complicated
forms of the process derive much illustration
from the study of the more simple, and we
may hope thus more fully to point out the
general importance of the functions now under
consideration.

We purpose to follow an arrangement
adapted chiefly to the consideration of Human
Generation. In all the animals in which dis-
tinction of sex subsists, the male and female
organs subservient to reproduction must co-
operate for the completion of the generative
process; and in the greater number of the more
perfect animals, as also in Man, the two kinds
of sexual organs being placed on separate in-
dividuals of the same species, the concurrence
of both these individuals, or of both male
and female parents, is necessary for the for-
mation of the fruitful products from which
the offspring proceeds. The circumstances,
then, which give rise to the union of the sexes,
and the phenomena which accompany that
union, form some of the topics of the present
article. The product of fruitful sexual union
in all animals is one or more eggs, from each of
which, under the influence of certain favourable
circumstances, different in different tribes, the
young animal is produced by an intricate pro-
cess of vital growth. The greater part of the
substance composing the egg is furnished by
the female parent : but this egg of the female
would be wholly barren, or would not undergo
any of those changes by which the young
animal is formed, unless it received in some
way or other the influence of the product of
the generative organs of the male ; and the egg
formed by the female may be regarded as im-
perfect until the change now alluded to has
been effected in it. It is then said to be
fecundated or rendered fruitful by the semen
of the male. The mode of formation of the
egg and seminal matter, the mode of their
separation from the place of their formation,
the structure and properties of each of these
products, the manner in which they are
brought together, the influence which they
exert upon one another, and the consequent
result in the production of the young, con-
stitute the principal remaining topics which
fall to be discussed by us at present. In this
article our attention must chiefly be confined
to such operations or functions of the male
and female parents as are preliminary to or
necessary for the formation of a ripe and fruit-
ful ovum, — that is, an egg capable of giving
birth to a new animal the same as either of its
parents, when placed in those circumstances
which are favourable to its evolution. It is
not intended to speak in this place of the
changes of the ovum itself in which the for-
mation of the young animal consists : the
consideration of these is reserved for the article
Ovi M.

2 F

426

GENERATION.

Before treating in detail of Human Gene-
ration, we introduce some remarks on the
nature of the reproductive function in general,
and a sketch of the principal varieties of the
forms it assumes in different classes of ani-
mals.

I. THE FUNCTION OF REPRODUCTION GENE-
RALLY CONSIDERED.

1. Introductory remarks. — The process by
which the young of animals are formed has,
from the earliest periods of science, always
been an object of peculiar interest and atten-
tion to inquirers into the functions of animated
beings. Scientific men as well as the more
ignorant have looked with a mixed feeling of
wonder and admiration upon the intricate
changes which precede and accompany the
first appearance and gradual formation of all
the different textures and organs belonging to
animal bodies. The gradual construction or
building up of the whole frame-work of the
animal body, and its various important organs,
— the formation of the nerves and brain that
feel and think, the muscles that move, the
blood with its containing organs that propel it
and apply it to the purposes of nutrition, —
the appearance step by step of all the remark-
able structures out of which the different
organs are formed, — the development of the
appropriate vital powers of each of them, —
the comparatively simple structure of the sub-
stance of the egg, and the impossibility of
detecting in it by the most exact scrutiny,
before the commencement of the formative
process, any appearance of the parts after-
wards arising there — have naturally led phy-
siologists to inquire minutely into the pro-
perties of that egg, and the process by which
so remarkable a production is generated. The
ascertained fact that the egg possesses vital
powers belonging to itself, and that its life is
in a great measure independent of that of its
parents, — that the vital powers of the egg are
capable of being called into operation and in-
fluenced in many animals by determinate
external physical agents, such as heat, air,
light, and electricity, — the obscure nature of
the influence exerted by the male upon the
female product in the perfecting of the egg, —
the preservation of the specific distinctions of
animals from one generation to another in un-
deviating succession, — the transmission of oc-
casional varieties or peculiarities of form and
of hereditary resemblances from parent to
offspring, — and, in fine, the important relation
which the generative process bears to other
functions of the animal economy, are among
the more prominent circumstances which,
while they throw a certain air of mystery over
the functions of reproduction, have at the same
time given them an interest in the eyes of the
physiologist, which increases as his acquaint-
ance with their details becomes more ex-
tended.

It is a common remark that generation is at
once the most obscure and the most wonderful
cf the processes occurring in organized bodies.
Hence, perhaps, it has happened that, while there

are few subjects of physiological inquiry upon
which so many authors have written, there is none
upon which so many have freely indulged their
fancies in framing unwarranted hypotheses and
absurd speculations. This is an error which
belongs to the early stage of investigation in
most branches of natural knowledge, and
which in the instance before us may be traced
very directly to the comparative want of cor-
rect information which for a long time pre-
vailed regarding the phenomena of the gene-
rative processes. For, if we except the re-
markable investigations of Aristotle, Fabricius,
Harvey, Malpighi, Wolff, and Ilaller, it may
be said that it is only towards the conclusion
of the last or the commencement of the pre-
sent century that our subject has been
studied with that accuracy of observation and
freedom from hypothesis which are calcu-
lated to insure steady progress in the attain-
ment of physical knowledge. When ex-
tended observation shall have rendered more
familiar to the physiologist the different steps
of the intricate processes by which an egg is
formed and the young animal is developed
from it, although he may not cease to admire
the changes in which these processes consist,
the feeling of wonder will be in a great mea-
sure lost to him ; and he will not be inclined
to look upon the gradual formation and growth
of the child as more extraordinary than the
constant and regular nutrition of the fully
formed body. Are the inscrutable workings
of the brain and nerves, the constant energy
of the beating heart, the unwearied and pow-
erful exertions of the voluntary muscles, the
secretion of different fluids from the glands,
and the regular supply of suitable organic
materials to all parts of the body, so as to
maintain the healthy structure of each and fit
them for the performance of their respective
offices, less remarkable and astonishing, or,
in other words, less far removed from our
accurate knowledge and comprehension, than
the first origin and early growth of the same
organs at a time when both their structure and
functions are greatly more simple ? Certainly
not. These remarkable changes are all objects
of wonder to the vulgar in proportion as they
are unknown. The man of science regards the
ultimate cause of all vital processes as equally
inexplicable, and, aware of the bounds set to
his knowledge of life, limits his inquiries con-
cerning its various processes to the investigation
of their phenomena.

At the same time it may be allowed that the
fact that the mere contact of the male seminal
fluid seems to awaken and call forth from the
otherwise inanimate egg all those vital powers
which are afterwards concerned in sustaining
the life of the new being, is one of the most
striking and simple examples of vital agency,
and one less suited than most others to be
observed or experimentally investigated. The
theoretical physiologist, in contemplating this
fact, is apt to conceive that here he has ar-
rived at one of the primitive causes or foun-
dations of animal life, and that he has here
obtained the key to many of its hidden won-

GENERATION.

427

ders : lie passes the limits which ought to
bound his inquiries, and in most instances
invents fanciful and curious speculations rather
than makes sound generalizations of ascer-
tained facts.

2. Theories of generation. — The vast num-
ber of the theories of generation renders it
impossible to mention even the more im-
portant in this place. Drelincourt, an author
of the last century, brought together so many
as two hundred and sixty-two " groundless
hypotheses" concerning generation from the
writings of his predecessors, " and nothing is
more certain," quaintly remarks Blumenbach,
" than that Drelincourt's own theory formed
the two hundred and sixty-third."*

Of these theories two principal classes may
be distinguished, according as they more di-
rectly relate, 1st, to the action of the parent
organs, or 2d, to the changes in the egg
belonging to the formation of the new animal.
Of the first of these classes of theories Haller
made three divisions, according as the offspring
is supposed to proceed, 1st, exclusively from
the organs of the male parent, 2d, entirely from
those of the female, or 3d, from the union of
the male and female products. The second
class of these theories, that, viz. which relates
more particularly to the formation of the new
animal, may be arranged under two heads,
according: as the new animal is supposed, 1st,
to be newly formed from amorphous materials
at the time when it makes its appearance in
the egg, or 2d, to have its parts rendered
visible, by their being expanded, unfolded, or
evolved from a previously existing though in-
visible condition in the germ.

The greater number of the older theories of
generation may then be brought under one or
other of the above-mentioned divisions, viz.
the theory of the Ovists, of the Spermatists,
that of Combination, Evolution or Epigenesis.

According to the first-mentioned of these
hypotheses, or that of the Ovists, the female
parent is held to afford all the materials neces-
sary for the formation of the offspring, the
male doing no more than awakening the forma-
tive powers possessed by, and lying dormant
in, the female product. This was the theory
of Pythagoras, adopted in a modified form by
Aristotle ; and we shall afterwards see that it
resembles most closely the prevailing opinion
of more modern times. The terms, however,
in which some of the older authors expressed
this theory are very vague, as, for example, in
the notion that the embryo or new product
" is formed from the menstrual blood of the
female, assisted by a sort of moisture descend-
ing from the brain during sexual union."

According to the second theory, or that of
the Spermatists, among the early supporters of
which Galen may be reckoned, it was supposed
that the male semen alone furnished all the
vital parts of the new animal, the female
organs merely affording the offspring a fit place
and suitable materials for its nourishment.

* See Blumenbach iiber den Bildungstrieb,12mo.
Getting. 1791. Anglice by A. Crichton : An Essay
on Generation, 12mo. Lond. 1792.

Immediately upon the discovery of the S€minal
animalcules, these minute moving particles
were regarded by some as the rudiments of the
new animal. They were said to be miniature
representations of men, and were styled ho-
munculi, one author going so far as to delineate
in the seminal animalcule the body, limbs,
features, and all the parts of the grown human
body. The microscopic animalcules were held
by others to be of different sexes, to copulate,
and thus to engender male and female off-
spring; and the celebrated Leeuwenhoek, who
was among the first to observe these animal-
cules, described minutely the manner in which
they gained the interior of the egg, and held
that after their entrance they were retained
there by a valvular apparatus.

The theory of Syngenesis or Combination
seems to have been applied principally to the
explanation of reproduction of quadrupeds and
man, the existence and nature of the ova of which
were involved in doubt. This hypothesis con-
sists in the supposition that male and female
parents both furnish simultaneously some semen
or product ; that these products, after sexual
union, combine with one another in the uterus,
and thus give rise to the egg or structure from
which the foetus is formed. In connexion with
this theory we may also mention that of Meta-
morphosis, according to which a formative
substance is held to exist, but is allowed to
change its form in order to be converted into
the new being ; as also the notion of Buffon
that organic molecules universally pervade
plants and animals, that these are all endowed
with productive powers, that a certain number
are employed in the construction of the textures
of organized bodies, and that in the process of
generation the superabundant quantity of them
proceeds to the sexual organs and there consti-
tutes the rudiments of the offspring.

The theories of generation proposed before
the commencement of the seventeenth century
are either unsatisfactory or erroneous from the
entire want of accurate knowledge prevailing
before that time regarding the relation of the
egg to reproduction. The conversion of one
animal into another, constituting equivocal or
spontaneous generations, was very generally
believed in ; and the process of the formation
of the egg was equally ill understood in the
lowor and higher classes of animals. It was in
the course of the seventeenth century that the
labours, first of Harvey, and afterwards of
Swammerdam, Redi, Malpighi, De Graaf, and
Vallisneri, gave rise to greater precision of
knowledge and opinions regarding this subject,
and finally established the Harveyan dictum,
" omne vivum ex ovo," which may be regarded
as the starting - point or basis of modern
researches.

The theories of generation seem after the
period of Harvey to have changed somewhat
their object, and to have been directed more
exclusively to the explanation of the formative
process, or the manner in which the parts of
the foetus are first formed in the egg and after-
wards attain their ultimate structure and con-
figuration.

2 r 2

428

GENERATION.

It was then that the foundation was laid for
the discussion between Epigenesis and Evolu-
tion, the two theories of generation which have
more recently occupied the attention of men
of science, and which, as has already been
remarked, relate principally to the nature of
the formative process. Harvey and Malpighi
may be regarded as the first who endea-
voured, from the observation of facts, to
establish the general law of Epigenesis as
opposed to the older views of Preformation
entertained by the Ovists or Spermatists ; but
it was not till near the middle of the last
century that these opinions were opposed to one
another in a decidedly controversial manner.

At that time Caspar Frederick Wolff* sup-
ported the system of Epigenesis by a reference
to observations on the minute changes of the
egg of the fowl during the early stages of
formation of the chick, while Haller and Bonnet
advocated the opposite opinion of Evolution.

Wolff and those who followed his system
held that no appearance of the new animal is
to be found in the perfect impregnated egg
before the commencement of incubation, but
that when the formative process is established
by the influence of heat, air, and other circum-
stances necessary to induce it, the parts of the
foetus are gradually put together or built up by
the apposition of their constituent molecules.
Hallerf referred both to his own observations
on the chick and to a variety of collateral
arguments in support of the system of Evolu-
tion, holding that when the foetus makes its
appearance in the egg, it does so merely in
consequence of the enlargement or evolution
of its parts which pre-exist, though in an
invisible condition, in the egg. Bonnet]: carried
this theory further than any one else, but
trusting mainly to the observations of Haller
on the formation of the fcetus, he supported his
overdrawn views on highly hypothetical reason-
ing. Bonnet, in what is termed the theory of
Emboitement, held not only that the whole of
the parts of the foetus pre-exist in the egg
before the time of their appearance, but also
that the germs of all the animals which have
been or are to be born pre-exist from the begin-
ning in the ovaries of the female ; that the
genital organs of the first parents of any species,
therefore, contain the germs of all their pos-
terity; that these germs lie dormant in their
abode until one or more are aroused by the
exciting influence of the male; and that con-
sequently there is not in nature the new forma-
tion of any animal.

We shall have occasion to shew in the article
OVUM that the most recent researches concern-
ing the mode of formation of the foetus in
birds, quadrupeds, and other animals, and
more particularly the microscopic observations

* Theoria Generations, published as an Inaugu-
ral Dissertation at Berlin in 1759, and republished
in 8vo. in 1774.

t Elementa Physiologiae, &c. torn. vii. Mem.
sur la formation du Cceur dans le Poulet. Lau-
sanne, 1753. Opera Minora, torn. ii.

t Palingenesie Philosophique, Geneve, 1769 ;
also in his Considerations stir les Corps Organises.

of Meckel, Pander, Baer, and Rathke,* have
shewn the theory of Epigenesis or super-
formation of parts to be much more consistent
with what is known from observation than the
theory of Evolution. In modern writings,
however, the term Development is, without
reference to theory, employed to denote the
mode of growth of the fcetus more frequently
than any other.

We would further remark in relation to our
present subject that various names have at
different times been given by authors gene-
ralizing the phenomena of development to the
powers supposed to operate in the formation of
the young; as, for example, the Anima vege-
tativa, Nistis format ivus, Vis plastica, Vis
essential'iSj expansive, resisting, and vegeta-
tive forces. These terms can be considered
as little else than general expressions of the
fact that the foetus is formed and grows in the
egg, and are not more satisfactory expla-
nations of the cause of its formation than the
hypothesis of organic affinity is of the process
of assimilation in the adult animal. As the
knowledge of minute anatomy and physiology
has increased, and the accurate observation of
the process of developement has been more
extended, the number of such hypotheses has
gradually diminished.

Thus the somewhat vague discussion as to
the relative probability of Epigenesis and Evo-
lution has led to the laborious and accurate
investigation of the various steps of the forma-
tive process or developement of the foetus, and
the conjectures as to the forces or causes which
give rise to the growth of the new animal have
fallen into comparative neglect; the erroneous
notions respecting the source of the germs of
male or female offsprings from one or other
ovary or testicle have been replaced by a more
satisfactory examination of the mode of deve-
lopment of the sexual organs in the early stages
of their advancement; and the inquiry as to
the share taken by one or other parent in the
process of generation has been pursued in more
modern times by the attentive investigation of
the functions of the male and female organs of
reproduction, upon the same principles that
guide the physiologist in his attempts to explain
any other class of functions of the economy.

Recent writings on our subject are not, how-
ever, altogether free from vague hypotheses of
the same nature as the older theories of gene-
ration above mentioned. The mechanical
explanation of fecundation by the entrance of
the seminal animalcule into the egg has been
revived by one author; a second considers
all the changes of development as under the
influence of electro-magnetic currents ; and a
third explains the same changes by attributing
them to a spontaneous motive power and
organic affinitive properties of the molecules
of the ovum.

It has been well remarked by Professor

* After these observers may be mentioned Serres,
Prevost and Dumas, Dutrochet, Rolando, Purkinje
and Valentin, Coste, and others, as contributing
materially to the knowledge of this subject.

GENERATION.

429

Burdach that the generative function, com-
prising the production of a fruitful egg and the
formation of the young animal from it, are
natural phenomena not more secret in their
essence than others occurring in organized
bodies, and which, therefore, ought to be
investigated by obtaining a knowledge of the
conditions in which they take place, and of the
operations and changes in which they consist.

The illustrious Harvey in his 51st Exercita-
tion expresses himself thus decidedly a sup-
porter of the theory of Epigenesis, — " it is
plain that the chicken is built up by Epigenesis
or the additament of parts budding one out of
another;" but he does not admit that separate
powers, such as the "alterative or immutative,
formative, attractive, retentive, digestive, and
expulsive faculties, or those of apposition,
agglutination, and assimilative nutrition de-
scribed by Fabricius," can be distinguished in
the production of the chicken. He thus limits
our knowledge of the subject in the 54th
Exercitation : " But as in the greater world
we say Jovis omnia plena, all things are full of
the Deity, so also in the little edifice of a
chicken, and all its actions and operations,
digilus Dei, the finger of God or the God of
nature doth reveale himself." " A more sub-
lime and diviner artificer (than Man is) seems
to make and preserve man ; and a nobler agent
than a cock doth produce a chicken out of the
egge. For we acknowledge our omnipotent
God and most high Creator to be every where
present in the structure of all creatures living,
and to point himself out by his workes ; whose
instruments the cock and hen are in the gene-
ration of the chicken. For it is most apparent,
that in the generation of the chicken out of the
egge, all things are set up and formed, with a
most singular providence, divine wisdom, and
an admirable and incomprehensible artifice."
" Nor can these attributes appertain to any but
to the Omnipotent Maker of all things, under
what name soever we cloud him ; whether it
be the mens divina, the divine mind with
Aristotle, or anirna mundi, the soul of the
universe with Plato; or with others natura
naturans, Nature of nature herself; or else
Saturnus or Jupiter with the heathen, or rather
as befits us, the Creatour and Father of all
things in heaven and earth ; upon whom all
animals and their births depend : and at whose
beck or mandat, all things are created and
begotten."*

3. Spontaneous generation of animals. — In
this introductory view of the function of gene-
ration, it may "be proper shortly to inquire
whether a regular affiliation from parent to
offspring be an indispensable condition for the
continuation of the species of every kind of
animal, — a question somewhat speculative in
its nature, but of considerable interest in rela-
tion to some of the general doctrines of physio-
logy, as well as closely connected with our
present subject. It has already been stated in

* Anatomical Exercitations concerning the Ge-
neration of Living Creatures. London, 1653,
p. 310 et seq.

general terms that origin by generation and the
power of reproduction are characteristics be-
longing to all organized bodies whether of the
vegetable or animal kingdoms. The existence
of life implies the sequence of decay and death,
or in other words, those varied operations and
changes which together constitute the living
state continue to occur in each organized body
for a limited period only : they sooner or later
undergo a gradual alteration, are less regularly
performed, and ultimately entirely cease in
death. But although every individual belong-
ing to the organized kingdom of nature is
necessarily subject to death, the species of each
plant and animal never becomes extinct, but
is continued upon earth in an undeviating suc-
cession of generations. The origin of a mineral,
on the other hand, is wholly independent of
any pre-existing body of its own kind ; and,
in the mineral kingdom, all those bodies are
held to belong to the same species which agree
in external form, physical properties, and
chemical constitution. The mineral owes its
first origin, as its subsequent increase, to the
simple union of its component particles ; but
the successive generations of every species of
organized bodies constitute an uninterrupted
chain extending from the time of their first
creation, and in which the formation of every
new link that is added depends on its tem-
porary attachment to that which preceded it.
So fixed, indeed, is the law of continued
reproduction of organized bodies, that many
naturalists have, in the absence of more definite
distinctive characters, adopted the circumstance
of reproduction as the only certain means of
determining what individuals ought to be
regarded as belonging to one species.

While most naturalists readily admit the
correctness of the above-mentioned general
law, some are inclined to hold that it is not
universally applicable, and that there are excep-
tions to it both in the vegetable and animal
kingdoms of organized nature. It is among
the simplest kinds of plants and animals that
these exceptions are conceived to exist, and
more particularly among cryptogamic plants
of the nature of mould, small microscopic
animalcules formed in infusions of decaying
organic matters, and the Entozoa which live in
the bodies of other animals. These living
productions are supposed by some to arise in-
dependently of others of the same kind, nearly
in the manner of minerals, by the aggregation
of their component molecules, with this diffe-
rence, that these molecules are of an organic
kind. This sort of production without parents
has been termed Spontaneous Generation. It
has also received at different times various
other appellations, such as equivocal, doubtful,
primitive, original, and heterogeneous gene-
ration.

At one time it was a common belief among
scientific men as well as the vulgar that
many animals might be produced by sponta-
neous generation, as for example, the numerous
insects or their larvae infesting putrid sub-
stances, various kinds of 'worms (Annelida),
and Molluscous animals, as well as even

430

GENERATION.

some fishes and reptiles ; but the increased
knowledge of the structure and habits of these
animals, and in particular the observations of
Redi* and others, demonstrated the error of
this opinion, and shewed it to have arisen
merely from the circumstance of their real
mode of generation not having been observed.
After this many felt inclined to reject entirely
the occurrence of spontaneous generation in
any class of organized beings, and at the present
day the question cannot be regarded as by any
means entirely set at rest. From the nature
of the observations and experiments required in
an investigation of this nature, there is almost
an impossibility of arriving at a perfectly satis-
factory conclusion ; but so far as the facts at
present entitle us to form an opinion, it may be
stated that spontaneous generation, if it occurs,
takes place in the simplest kinds of organized
beings only ; that in most of them it is only
occasional ; and that therefore this form of ge-
neration is to be looked upon as a rare excep-
tion to the usual and almost universal mode of
reproduction by the separation of a living por-
tion from a parent body.

Minute animalcules, the greater number of
which are so small as to be visible only with
the microscope, are formed in the infusions of
almost all kinds of organic matter, such as
starch, sugar, gum, seeds, and different animal
substances, when these infusions enter into pu-
trefaction. The kinds of these animalcules are
very numerous, and the circumstances which
seem to determine the formation of one or other
sort are infinitely varied. Thus the nature of
the substance suspended in the infusion ; and,
in the same infusions, the degree of heat, the
extent of the decomposition, the quantity and
nature of the air admitted, the rapidity with
which it is renewed, and the strength of the in-
fusion or the relative proportion of water and
organic matter in it, all appear to exert a certain
influence in determining the formation of one
or other of the kinds of animalcule.

Two suppositions may be entertained regard-
ing the first origin of Infusoria ; the one, that
of their spontaneous generation ; the other, that
of their developement or evolution from some
pre-existing egg or germ. Those who disbe-
lieve in the first and adopt the second hypo-
thesis hold that the ova of the animalcules exist
in the substances of the infusions, or are float-
ing every where in the atmospheric air ; that
these ova become developed in that species of
infusion only which is suited to serve as
their proper nidus or matrix ; and that all the
varieties of animalculse in different infusions
depend upon the infusions being suited, from
their composition or the external agencies to
which they are subjected, to cause the develop-
ment of different sorts of ova. The supporters
of the hypothesis of Spontaneous Generation
hold, on the other hand, that certain changes
of composition of the organic molecules in the
infusions, in whatever way induced, are the sole
cause of the formation of one or other kind of
animalcule.

* De Generatione Fnsectorum. Amst. 1686.

Spallanzani,* one of the most strenuous op-
ponents of the hypothesis of spontaneous gene-
ration, shewed by very accurate experiments
that no animalcules are formed when the access
of air to the infusion is completely prevented, as
for example, when it is covered with a little oil, or
the vessel containing it is closely sealed ; and
he thence concluded that the germs of the ani-
malcules must exist in the atmosphere ; but the
supporters of the hypothesis consider them-
selves as entitled to hold that no production of
animalcules takes place in these circumstances,
merely because the exclusion of the air has the
effect of preventing that species of decomposi-
tion which they regard as necessary for the
formation of the Infusoria.

It is stated by some experimenters that ani-
malcules are produced when the infusions are
exposed to hydrogen and nitrogen gases, or to
atmospheric air artificially prepared ; in which
it is held that there can be no living ova of
animalcules. Again, it appears from numerous
experiments, that when the infusions have been
exposed to a boiling temperature, which is ge-
nerally believed to have the effect of destroying
the life of all organized productions, the quan-
tity of animalcules formed is not diminished.
Some air, it has already been stated, must always
be present ; but so far as we are aware, the ex-
periments on this point have not been per-
formed in such a manner as to ascertain, whe-
ther or not, when an infusion is allowed to come
in contact with a considerable portion of con-
fined air, and the whole apparatus is exposed
to a temperature above that of boiling water,
the production of Infusoria may still take place;
and we are consequently obliged, in the absence
of more direct experiment, to have recourse to
analogical reasoning.

The following considerations appear to us to
throw the balance of evidence in favour of the
spontaneous production of Infusoria, mould,
and the like.

Firstly, those organic matters which are most
soluble in water, and at the same time most
prone to decomposition, give rise to the greatest
quantity of animalcules or cryptogamic plants.

Secondly, the nature of the animalcule or
vegetable production bears a constant relation
to the state of the infusion, so that, in similar
circumstances, the same are always produced
without this being influenced by the atmo-
sphere. There seems also to be a certain pro-
gressive advance in the productive powers of
the infusion, for at the first the animalcules are
only of the smallest kinds or Monades, and after-
wards they become gradually larger and more
complicated in their structure ; after a time the
production ceases, although the materials are
by no means exhausted. When the quantity
of water is very small and the organic matter
abundant, the production is usually of a vege-
table nature; when there is much water, animal-
cules are more frequently produced.

Thirdly, on the supposition that infusory ani-
malcules are developed from ova, it is neces-

* Tracts on the Nature of Animals and Vegeta-
bles. Edin. 1799, (transl.)

GENERATION.

431

sary to conclude, from the experiments already
referred to, that these ova are in some instances
derived from the atmosphere, but yet the num-
ber of Infusoria is by no means indirect pro-
portion \vith the quantity of air. We are also
reduced to the necessity of holding that every
portion of the atmospheric air is equally im-
pregnated with infusorial germs or ova, and
that these bodies may remain for years dis-
solved, as it were, or invisibly suspended in the
atmosphere, and in a perfectly dry state — a
supposition contrary to analogy, and not fully
warranted by the fact that Vibriones may be
resuscitated by means of moisture after they
have been kept in a dry state for long periods.

Fourthly, it may be remarked that the exist-
ence of ova, as belonging to many of the Infu-
soria, is entirely hypothetical, since most of
these animals are known, when once formed, to
propagate by other means, as by the division of
their whole bodies or by budding.

The production of infusorial animalcules
from solutions of granite, silex, &c. recently
described by Mr. Crosse, we have no hesitation
in pronouncing to be either a mistake, or the
result of changes occurring in admixed particles
of organic matter.

The Entozoa, or that class of animals which
live only in the bodies of others, afford proofs
of spontaneous generation still more convincing
than those already mentioned. These remark-
able animal productions are capable of existing
no where but in the bodies of those animals
which they naturally inhabit : they live either
loose or attached, within cavities or imbedded
in the substance of the textures ; sometimes in
places, such as the alimentary canal or respira-
tory passages, to which the external air has
access, and at other times in close cavities of
the body, into which there is no opening from
without, such as the chambers of the eye, the
serous sacs, cysts, and other cavities, in the
parenchyma of organs, the bloodvessels, &c.
Entozoa do not live for any length of time after
being discharged from the natural places of
their abode ; and they survive a very short time
only after the death of the animals in which
they live.

If Entozoa are not admitted to be the pro-
duct of spontaneous generation, in order to ac-
count for their origin, it becomes necessary to
suppose either that these creatures themselves
or their ova pass directly from one animal to
another, or that they are introduced through the
medium of air or water. Upon the first sup-
position, carnivorous animals ought to be
affected with entozoa, at least in greatest quan-
tity, if not in some instances exclusively ; and
the entozoa infesting any particular animal
ought to be of the same kind as those which
exist in the animal serving it for food. But
such is by no means the case. Herbivorous as
well as carnivorous animals have entozoa, and
in no less quantity, and each animal is the
abode of its own peculiar kind. The same en-
tozoa infest the same animals in all localities
and climates; thus all the human entozoa, with
the exception of the Dracunculus or Guinea-
worm, which is an external parasite rather

than a true entozoon, are the same in all races
of men. Neither do we recognise any simi-
larity between the entozoa infesting animals of
a particular district and allied tribes of animals
living in the neighbouring waters.

In adopting the second supposition that the
eggs or germs of Entozoa may gain the bodies
of animals by circuitous routes, we are met by
many difficulties in addition to those already
stated in reference to a similar explanation of
the origin of Infusoria. Many Entozoa reside
only in particular organs of the body, and in
the very interior of these organs, as the human
Cysticercus cellulosus in the choroid plexus of
the brain, in the substance of the brain itself,
in the chambers of the eye, &c. so that it is
necessary to suppose the ova of Entozoa to have
been introduced into the circulation, carried
through the smallest bloodvessels, and depo-
sited in the places in which they are developed.
Animals living in the same situations and feed-
ing on the same substances have different kinds
of Entozoa. The ova of some of the Entozoa,
as for example, those of the common round
worm, (Ascaris lumbricoides,) are so large that
they could not pass through the largest even of
the capillary bloodvessels : the ova are so heavy
that they could not be transmitted through the
atmosphere ; and the supposition of the passage
of the ova from parent to offspring is opposed
by the mechanical difficulty of the transmission,
as well as by the facts that parent and child
are not always affected with the same kinds of
worms, and that though the complaint of worms
may be said to run in families, yet many escape,
and one or more generations in the hereditary
succession are frequently exempt from it. En-
tozoa have been observed in the foetus of ani-
mals, and supposing them to be introduced from
without, it would be necessary to hold that the
entozoa themselves or their ova have passed
directly from the mother to the child in the
uterus, or to have traversed a route through
which the globules of the blood are not trans-
mitted.

Some of the Entozoa, we may further remark,
when once formed, are viviparous or bear their
young alive ; and with regard to these kinds it
would be necessary to suppose that they may
arise by invisible ova or germs as well as pro-
pagate in the viviparous mode.

These facts appear to us to speak strongly in
favour of the occasional occurrence of sponta-
neous generation, — " a doctrine which, had it
not been applied in many instances where it
was manifestly untrue, would have met with
less ridicule and a more just appreciation than
it has usually obtained." The epithet " spon-
taneous," which we have retained as the most
common, is equally inappropriate as applied to
this or to any other of the processes of nature ;
and the analogy of by far the greater number of
plants and animals militates against the proba-
bility of the hypothesis ; but it must at the
same time be held in mind that the organized
bodies in which spontaneous production has
been said to occur differ widely in their general
structure and functions from those which are
reproduced by means of ova; and we are

432

GENERATION.

scarcely entitled to reject the hypothesis of their
spontaneous generation, merely on the ground
that, in this respect, they do not agree with the
rest of the animal kingdom. IJarvey even,
who established the proposition ornne vivum ex
ovo, seems yet to have acknowledged the ne-
cessity of admitting some difference between
the more ordinary form of generation by means
of an egg and that which he called of the spon-
taneous kind.*

In conclusion, we may remark, that while
we feel inclined to admit the existence of spon-
taneous generation among some species of cryp-
togamic plants, infusorial animalcules, and en-
tozoa, it must be held in recollection that many
of these productions, after their first origin,
propagate their species as parents, — that the so-
called spontaneous kind of generation is to be
looked upon as no more than an exception to
the general law of reproduction, — and that
therefore extreme caution is necessary in admit-
ting any organized body to be the product of
spontaneous generation upon the mere negative
evidence of the absence of its seeds or ova.

II. SKETCH OF THE PRINCIPAL FORMS OF
THE REPRODUCTIVE FUNCTION IN DIFFE-
RENT ANIMALS.

Before proceeding to detail the different steps
of Human Generation, which forms the more
immediate subject of consideration in this arti-
cle, we shall endeavour to present a short pre-
liminary sketch of the various forms which the
reproductive function assumes in different classes
of animals.

Reproduction may be divided into non-sexual
and sexual, according as the whole process is
accomplished by one class of organs in a single
individual, or by the concurrence of two diffe-
rent kinds of organs placed either upon one or
upon two separate individuals of the same
species ; the first form occurring among the
simplest kinds of animals only, the second be-
longing to all the vertebrated and the higher
classes of invertebrated animals.

1. Non-sexual rtproduction. — Of the non-
sexual mode of reproduction three principal
kinds may be distinguished, viz. first, by divi-
sion ; second, by attached buds ; and third, by
separated gemmae.

Fissiparous generation. — The most common
form of the fissiparous generation, as the first
of these varieties has been called, is met with
in some of the simpler Infusoria ; but it also
occurs occasionally in animals higher in the
scale. It consists essentially in the division of
the parent animal body into a certain number
of subordinate masses, each of which, being
endowed with independent life, becomes a new
individual similar to that of which it originally
formed a part. In some of the Infusoria in
which the process of subdivision has been mi-
nutely observed, fissures are seen to form in the
sides of the animal which is about to be repro-
duced; these fissures gradually enlarge, and
meeting with one another, completely separate

* Sre his Exercitations, as before quoted,
pp. 327 and 343.

the parts. In one kind of fissiparous genera-
tion the parent body is split into irregularly
shaped masses, in some two in number, in dif-
ferent others, four, six, eight, or twelve, and in
one, the Gonium pectorale, into as many as six-
teen. Each of the subordinate masses, when
first separated from its fellow, has an irregular
shape, from which it gradually passes into the
form and size of its parent.

In a second form of the fissiparous genera-
tion, the infusorial animal is divided into two
equal and symmetrical halves ; in some in-
stances in a longitudinal direction, as in Bac-
cillaria and some Vorticellse ; in others in a
transverse direction, as in Paramoecium, Cycli-
dium, and Trichoda.

The propagation of the Volvox globator, a
remarkable infusorial animalcule, may perhaps
be considered as belonging to the first of the
above-mentioned varieties of fissiparous genera-
tion.* This animal consists of an external
vesicle of a lenticular shape, moving rapidly
through the water by means of cilia in a whirl-
ing manner. Within this outer vesicle there
are smaller ones of the same kind, in the inte-
rior of each of which still smaller ones may be
distinguished by the aid of a high magnifying
lens. The outer vesicle may be regarded as
the parent, and the inclosed vesicles as its
young, for in propagation the outer vesicle
bursts and is torn into shreds, while the inclosed
ones are set free, each of them to execute its
independent motions in the water, and in its
turn to burst, and thus propagate its like in
discharging those which it contains.

A fissiparous kind of generation is not, how-
ever, confined to the Infusoria, but occurs also
in some of the Cestoidea and Annelida. The
most remarkable example is met with in the
Nais and Nereis. In the first of these genera,
a small portion separated from the tail becomes
the new animal. Before the actual separation
of this caudal portion, it is marked off from the
rest by a notch, and there are gradually formed
on its sides the joints, hairs, and other indica-
tions of the organs of the complete animal in
miniature. The notch enlarges, and the part at
last drops off capable of independent existence.
In the Nais, that part of the offspring by which
it is attached to the parent becomes the head,
and in this way, according to the singular
notion of Gruithuisen, who observed this sort
of reproduction with attention,-]- the tail of a
Nais may be considered as gifted with perpe-
tual life, since this part is extended into each
of the new descendants.]:

We may regard as somewhat analogous to
this kind of propagation the multiplication of
individuals by division, which happens occa-
sionally only or from accident in several of the
lower animals which are usually reproduced

* Another view taken of the reproduction of the
Volvox globator is, that the young are formed in
the manner of internal buds.

t Nov. Act. Nat. Curios, torn. xi.

f The segments of the infusorial animalcule
that is propagating in the fissiparous mode are
united by the parts which afterwards become the
tails of the new individuals.

GENERATION.

433

in another manner. The most remarkable ex-
amples of this are met with in Polypi, Entozoa,
and Annelida. When the Hydra viridis is cut.
through either longitudinally or transversely,
each segment continues to live and grow, and
is gradually furnished with those parts of the
body of which it was deprived by the division.
Thus, when the polype is divided across the
body, the part with the head and tentacula is
gradually furnished with a body, while ten-
tacula grow on the elongated extremity of the
other part. When, again, the animal has been
divided in a longitudinal direction, and four
tentacula are left on each part, the opposite
edges of each segment turn round and unite
so as to complete the tube of the stomach,
and four additional tentacula are formed upon
each.

Segments of the Tape-worm, Filaria, and
also of some other Entozoa, are capable of
living after separation and being converted in-
to independent animals. In the Leech and
Earth-worm, as well as some other Annelida,
the division of the body into two or more seg-
ments is not invariably followed by death, but
some or all of the portions continue alive, and,
acquiring the deficient organs, become con-
verted into more or less perfect animals.

Gemmiparous generation. — The second form
of non-sexual propagation that deserves our
attention is that in which the new individual
grows upon the parent as a bud or sprout, at
first exhibiting little appearance of the form or
structure of the perfect animal ; gradually as-
suming its form while still attached to the
parent stem ; and being afterwards separated to
enjoy independent existence.

The best known examples of this kind of
generation occur in the polypine and coralline
animals, and the process has been observed
with great attention by Trembley in the Hydra
viridis.* In this animal the young polype
makes its first appearance as a small conical
eminence on the body of the parent : this gra-
dually enlarges and becomes cylindrical ; a
cavity is formed in its interior, which at first is
separate, but afterwards comes to communicate
with the stomach of the parent, so that aliments
taken by the parent penetrate into the stomach
of the offspring. As the new polype enlarges,
the internal cavity opens at the free extremity,
where a mouth, provided with tentacula, is
formed. The young animal then catches and
swallows food for itself : this food at first finds
its way into the stomach of the parent, but after
some time all communication between the two
stomachs is prevented by the closure of the root
of the stem of the small polype ; and afterwards
the offspring is detached from the parent, be-
comes a separate individual, and in its turn
propagates new ones from its sides. The time
at which the separation takes place seems to
depend in some measure on the quantity of
food within the reach of the parent ; this occur-
ring at an early period when the supply is small,
and when there may be supposed to be a ne-

* Mem. pour servir a 1'Hist. des Polypes d'eau
douce. Leyden, 1744.

cessity for the young to move about from place
to place in search of sustenance. Sometimes
indeed the separation is much retarded, and the
young ones also propagate while remaining on
the parent stem ; so that the polype assumes a
bmnched form, the parent stem bearing families
of several generations.

The Sertularia, Vorticella, Zoantha Ellisii,
and Cornularia Cornucopias, also propagate by
shoots somewhat in the same manner as the
Hydra.*

Reproduction by separated buds orsporules. —
The last form of the non-sexual reproduction is
that in which the young are formed from small
detached masses after they are separated from
the body of the parent . These bod i es, general ly
of a rounded form, maybe regarded as buds
formed in the parent body, as those of polypes
are, but detached from it before the evolution
of the new animal begins. They bear the same
relation to the offspring as the egg of higher
animals to their foetus or embryo, and might
be regarded as ova but for an important dif-
ference of structure to which we shall after-
wards advert. They are called sporae, germina
granulosa, and gemmae, or germs : they are
homogeneous in their structure, and the whole
of the substance of which they are composed is
converted in the process of their development
into the new animal.

In some animals these sporules are formed
in all parts of the body indiscriminately, and
are therefore found dispersed through it ; in
others there is present a peculiar organ in which
they are formed, constituting the simplest form
of a reproductive organ. The Actinia, Me-
dusae, and some of the lower tribes of Mollusca
belong to the first of these sets. In the Aphro-
dita the sporules lie in the interstices between
the different organs of the animal. In those
animals in which a particular organ is provided
for the formation of the sporules, the name of
ovary is given to that organ, — an application of
the term not strictly correct, as it belongs more
properly to the organ in which complete ova are
produced. The production of sporules from a
particular generative organ is much the most
frequent mode of their formation, and it ob-
tains in the greater number of the lower tribes
of Mollusca.

It is a fact worthy of notice that the spo-
rules of some Zoophytes, as those of the Sponge
observed by Dr. Grant, are endowed with a
faculty of moving, sometimes darting with ra-
pidity in various directions through the fluids
in which they are produced. These motions
seem to depend on Cilia: the sporules are also
provided with a hook, by which they become
attached to other objects when they settle,

* According to Burdach the propagation of the
Volvox globator, already mentioned, and of the
Vibrio, Cercaria, and Cysticercus, is effected by the
formation of buds, and differs from that of the
polype merely in the buds being formed and dis-
charged inwardly. We might, perhaps, consider
the regeneration of lost parts which takes place in
some animals higher in the scale than those pro-
pagating by buds as a manifestation in them of a
similar power.

434

GENERATION.

preparatory to their growth and conversion into
the fixed and immoveable Zoophyte.

We may here recal to the recollection of the
reader that the different forms of non-sexual
reproduction which we have now attempted to
sketch are not confined respectively to par-
ticular classes of animals, for several of these
animals are reproduced in more than one
manner.

The alleged instances of non-sexual propa-
gation occurring in animals higher in the scale
than those already mentioned are very doubt-
ful, and ought to be regarded either as founded
in imperfect knowledge of their reproductive
organs, or as rare exceptions to the general law
of their propagation by the sexual mode. *

2. Sexual reproduction. — The existence in
animals of generative organs of two kinds, and
the necessity of the co-operation of both these
organs in reproduction constitute the distinc-
tion of sex, or of male and female. In sexual
reproduction both kinds of organs produce a
substance essentially concerned in the process.
The product of the female organ, or ovarium,
as it is called, is the ovum or egg, a consistent
organised body of a regular and determinate
shape, in which the new animal is first formed
and resides during its early growth. A whitish
fluid is almost always the product of the male
organ or testicle, — termed semen, or the semi-
nal fluid, from a belief formerly prevailing that
it constituted, like the seed, the greater part of
the new being.

Nature of the ovum. — The egg is naturally
produced by the female without the concur-
rence of the male, that is, the whole substance
is apparently formed by the female organ, but

* In many of those instances in which female
animals have been supposed to give rise to produc-
tive ova, the males have at first escaped notice from
the smallness of their number or other causes ; and
with regard to others of the lower animals, it may
very reasonably be doubted whether the products
called ova have not been rather of the nature of
gemmae or sporules, such as those formed in the
Actinia and other animals naturally propagating in
the non-sexual manner. As in this predicament
may be mentioned, according to Burdach, Oxyuris,
Filaria, Ligula, Tricuspidaria, and others of the
Entozoa ; Serpula, Sabella, and other Tubicola ;
Cirrhopoda, and Mussels, and Scutibranchiata and
Cyclobranchiata, The Syngnathus was erroneously
regarded by Pallas, and the Perca Marina by
Cavolini, as propagating without sex. It is, how-
ever, probable that some animals provided with
both sexual organs, and which usually propagate
in the sexual mode, are occasionally reproduced
without the immediate concurrence of the male.
Thus the female Aphis, after being once impreg-
nated by the male, bears, for a certain portion of
the year, female young only, which are capable of
being reproduced for nine generations without any
of these female animals receiving any new influence
from the male. In the last of these generations
occurring in autumn, males also are produced which
impregnate the females destined to carry on the same
succession of generations during the next season.
According to some this extension of the fecun-
dating influence of the male through more than one
generation is not confined to the animals just men-
tioned ; but without doubt the instances in which
this has been supposed to be the case have been
greatly over-reckoned.

the egg so formed is incapable of giving birth
to a new animal unless it receive a certain por-
tion of, or influence from, the seminal sub-
stance of the male. This addition of seminal
fluid to the egg makes no immediate percep-
tible alteration in its structure or appearance,
but awakens in it the power of reproduction,
fructifies or fecundates it by causing a physical
or vital change, the essential nature of which is
not fully understood.

In the egg immediately after its fecundation,
none of the parts of the new animal are
visible. A certain time must elapse during
which the egg is exposed to certain favourable
influences of heat, air, &c. before the com-
mencement of those changes of development
and growth in which the formative process of
the new animal consists. The great mass of
the substance composing the egg consists of a
fluid, holding in suspension granules of animal,
albuminous, and oily matter. The form of the
egg is given by the external coverings, and
there is in every egg a determinate part or re-
gion, corresponding in all animals, at which
the small rudimentary parts of the embryo first
make their appearance. To this part of the
egg, which might be called its germ, the power
of independent life and reproduction appears
more immediately to belong; the granular fluid
serves but to afford nourishment to the young
being for a certain period. A gemma or spo-
rule, on the other hand, is generally held to
differ from the ovum in being homogeneous in
its structure, having no investing membranes,
and being entirely converted into the substance
of the new animal produced from it. In the
present state of our knowledge, however, the
distinction between an ovum and a sporule
must be admitted to be somewhat arbitrary.

The position of the male and female genera-
tive organs upon the same or upon different
individuals, and the place or manner of the
development of the young animal from an egg,
are the two most prominent circumstances in
regard to which the forms of sexual reproduc-
tion differ from one another in various animals.
The principal processes in which sexual re-
production essentially consists, are, 1st, the
formation of an egg by the female organs ;
2nd, the secretion of the seminal fluid by the
male organ ; and 3rd, the union of the sexes,
and means by which the seminal fluid is ap-
plied to the egg so as to confer fecundity
upon it.

Hermaphrodite generation. — In some of the
lower tribes of animals belonging chiefly to
the Annelida, Acephala, and Gasteropoda, the
male and female sexual organs are placed on
one individual, an arrangement of the sexual
organs termed Hermaphrodite, and all the indi-
viduals belonging to one species are consequently
similarly formed In Insects, Crustacea, some
of the Mollusca, and all the Vertebrata, the dif-
ferent sexual organs are placed on two distinct
individuals, which are thus constituted respec-
tively male and female. In the greater number
of those animals in which the last-mentioned
arrangement exists, besides the sexual pecu-
liarities, there are in each certain general differ-

GENERATION.

435

ences in the structure of the other parts of the
body.

In Hermaphrodite animals there are two
modes in \vhich fecundation takes ^place. In
some of the Acephala, and in the Holothuriae,
the union of the sexual organs necessary for
fecundation takes place in a single individual;
while in others, as Helix and Lymneus among
the Gasteropoda, copulation, or the union of
two individuals, is required, and there is mutual
impregnation, the female organ of each animal
being fecundated by the male of the other, —
a mode of impregnation which also exists in
the common Earth-worm, Leech, and some
other animals. Occasionally we find that three
or more individuals engage in this sort of mu-
tual fecundation, being arranged in a chain or
circle.* (See HERM APHRODITE.)

Dioecious reproduction, or ivit/i distinct in-
dividuals of different sexes. Oviparous and
viviparous generation. — In those animals again
in which the position of the sexual organs on
separate individuals renders copulation neces-
sary, the mode of production of the new animal
from the egg seems to be the most prominent
circumstance according to which the reproduc-
tive process is modified. Thus, while in a
certain number of them the young are born
alive, in others they are hatched from eggs laid
by the female parent. This constitutes the
difference between Viviparous and Oviparous
animals ; to the first of which classes Mam-
malia belong, to the second Birds, and most
Reptiles and Fishes. A short comparison of
the more important steps of the generative
process in the Mammiferous animal and the
Bird will most readily explain the difference
between viviparous and oviparous generation.!

* In the Cyclostoma viviparum the sexes are
distinct.

t Harvey in the Sixty-third Exercitation thus
enforces the analogy between the oviparous and
viviparous modes of reproduction. " I have
already given you the reason why I have drawn
out documents concerning all other egges from
the egges of Hens ; namely, because they are
cheap and every man's purchase. " — " But there
is more difficulty in the search into the gene-
ration of viviparous animals ; for we are almost
quite debarred of dissecting the humane uterus :
and to make any inquiry concerning this matter in
Horses, Oxen, Goats, and other Cattel, cannot be
•without a great deal of pains and expense. But
those who are desirous to make tryal whether we
deliver the truth or not, may essay the business in
Doggs, Conies, Cats, and the like." — " But we in
the entrance of these our observations have con-
cluded that all animals are in some sort produced
out of an egg : For the fo2tus of viviparous creatures
is produced after the same manner and order out of
a pre-existent conception, as the chicken is formed
and constituted out of an egge. There being one
and the same species of generation in them all,
and the exordium or first principle of them all is
either called an egge, or at lest something answer-
able and proportionable to it. For an Egge is an
exposed conception from which a Chicken is pro-
duced ; but a conception is an egge retained within,
untill the fcetus have attained its just bulk and
magnitude : in other matters it squares with an
egge," &c. " Besides, as a Chicken is hatched out
of an Egg, by the fostering heat of the sitting Hen,
or some other ascititious hospitable patronage, so
also the foetus is produced out of the conception in

In both these classes of animals ova are
formed from the ovary, and in both the ova
are fecundated within the body of the female
parent. The process by which the egg is sepa-
rated from the place of its formation, and the
changes it undergoes in being perfected after
this separation, are the same in both : but after
the fecundation and completion of the egg, it is
differently placed in the two classes of animals ;
for in birds the egg passes through the oviduct
and leaves the body of the female parent, to be
hatched into life under the influence of favour-
able external agents ; while in the mammiferous
quadruped, the egg remains within the uterus
of the female generative organs, becomes at-
tached to it, and has there formed from it the
young animal, which does not quit the body of
the parent until it is capable of independent
life. The egg of the bird leaves the body of
the mother provided with a considerable quan-
tity of organic matter, by which alone, under
the influence of heat and air, the embryo is
nourished during incubation. The egg of the
mammiferous animal is extremely small com-
pared to the size of the young animal at birth,
and the fcetus consequently draws a continual
supply of the materials of its nourishment from
the uterus of the mother, with which it is more
or less intimately connected. The residence of
the child or young animal in the body of the
mother during its formation and growth is
termed pregnancy, or utero-gestation.*

Ovo-viviparous generation. — There are other
animals, however, besides Mammalia, which
bear their young alive, as is the case in many
cartilaginous and a few osseous fishes, in
several Batrachia, Sauria, and Ophidia, and
also in some Gasteropodous Mollusca, Insects,
Annelida, and Entozoa. But there is an im-
portant difference to be pointed out between
the viviparous form of generation occurring in
these animals and that which belongs to the
Mammalia. For the female generative organs
of the above-mentioned animals, as well as
the eggs they produce, resemble much more
closely in their structure those of oviparous
than those of strictly viviparous animals. As,
in the animals now under consideration, the

the egge, by the soft and most natural warmth of
the parent. — " And then, concerning that which
relates to procreation, the foetus is produced out of
the conception in the selfe same manner and order
as the chicken out of the Egg ; with this only dif-
ference, that in an egge, whatever relates to the
constitution and nutrition of the Chicken, is at once
contained in it ; but the conception ( after the foetus is
now formed out of it) doth attract more nourishment
out of his parent's womb j whereupon the nourish-
ment increases with the foetus." — " The first Con-
ception, or Rudiment, therefore, of all Animals is
in the uterus," (this applies to Quadrupeds,)
" which, according to Aristotle, is like an egg co-
vered over with a membrane when the shell is
pilled off." And Harvey finally concludes with
Aristotle : "All animals, whether they be swimming,
walking, or flying animals ; and whether they be
born in the form of an Animal or of an Egge ; are
all generated after the same manner."

* The nature of the egg of viviparous animals,
which has only recently been fully understood,
will be described in a subsequent part of this paper,
and more in detail in the article OVUM.

436

GENERATION.

egg is proportionally large, the foetus grows
principally by the assimilation of materials
procured from it, and there is not that intimate
connection of structure nor interchange of
substance between the mother and fetus which
occurs in Mammalia. The term ovo-viviparous
is applied to the variety of reproduction now
under consideration; as expressing that in it,
although the foetus is produced fully formed
and alive, the ovum is merely hatched within
the parent body. We find, accordingly, that
this form of generation is liable to vary, and
occasionally to run into the truly oviparous
kind. Thus, some animals which bear live
young at one season lay eggs at another season
of the year, as occurs in some Insects ; and
in others, as Lacerta agilis, the ova remain
within the mother's body for a part only of the
time employed in the development of the young;
the process of hatching beginning and going
on for a longer or shorter time within the
female parent, and being completed as in the
bird without.

In all truly viviparous, in most ovo-vivi-
parous, and also in many oviparous animals,
the ova are fecundated within the parent's
body ; and we find provided for the purpose
of introducing the seminal fluid into the female
genital organs, a more or less complicated ap-
paratus in both male and female, by which
the union of the sexes is brought about. In
the greater number of strictly oviparous ani-
mals, and particularly those that are aquatic,
as osseous fishes and Batrachian Reptiles,
fecundation is operated externally to the pa-
rent body ; that is, there is no union of the
sexual organs of the male and female, but the
ova laid by the female are covered with a
certain quantity of seminal fluid shed by the
male.*

Utero-gestation in the Mammalia is termi-
nated by parturition or the birth of the young ;
while in the bird or oviparous animal birth con-
sists in the exclusion of the young from the egg.
At this period in Mammalia, the organic con-
nection between mother arid offspring is dis-
solved, and in both viviparous and oviparous
animals the birth is accompanied by important
structural changes, which fit the offspring for
independent life and aerial or aquatic respira-
tion. The young of Mammalia after birth,
though they cease to be organically connected
with the mother, continue to derive a certain
quantity of support from her, feeding on the
milk secreted by the mammae. But in all
other classes of animals, the young are at birth
capable of feeding on external aliment.

Varieties in respect to utero-gestation and
the developement of the young. — There is con-
siderable variety among different animals in
the degree of perfection at which the young
have arrived at the period of birth. Thus,
Insects, Batrachian Reptiles, and some other

* In the land Salamander, which is ovo-viviparous
and breeds in the water, although there is no sexual
union of the male and female, there is yet internal
fecundation, the seminal fluid being carried into
the oviduct of the female along with the water in
which it is effused.

animals leave the egg at a very early period ;
differing widely from their parents in struc-
ture and functions, they live for a time in a
masked or larva condition, and undergo after-
wards various changes or so-called metamor-
phoses before attaining the mature condition.
Fishes leave the egg while their structure is
yet very incomplete ; and even in the higher
animals we observe varieties in this respect :
thus, some birds, more especially those build-
ing on trees, are unfledged, blind, and help-
less when the shell is broken; and some
quadrupeds, among which may be mentioned
the Rodentia, Feline, and Canine species,
are at birth blind and weak, and with little
power of supporting their natural high tem-
perature.* The most remarkable instance
of variety of the kind now alluded to, how-
ever, occurs in the Kangaroo and other Mar-
supial animals, the generation of which de-
serves more particular mention in this place
as it exhibits a considerable deviation from the
more ordinary reproductive process in Mam-
malia, and is attended with some important
modifications in the structure of the generative
organs.

In the Mammalia generally, it has already
been stated that there is an intimate organic
connection between the foetus and mother, by
means of which the former is supplied with
the materials of its growth. The intimacy of
this union (as we shall explain more fully else-
where) varies much in different tribes of ani-
mals. It is greatest in the placenta of the
human female, and from this there may be
traced a series of animals in which it becomes
more and more loose. According to recent
researches in Comparative Anatomy, there is
also observable in the descending series of
these animals a nearer and nearer approach in
the general structure of the body, and in the
conformation of the generative organs to the
oviparous type. This approach to the ovipa-
rous structure is most strongly marked in the
Marsupiata, as the Opossum, Kangaroo, &c.
and in the Monotremata, as the Ornithorynchus
and Echidna.f

Marsupiate generation. — The foetus of the
marsupiate animal leaves the uterine system of
the mother or is born at an early period of its
formation, while it is yet of a very small size,
and its organs are comparatively imperfectly
formed. On being born it is introduced by
the mother into the pouch or marsupium
formed by a reduplication of the integuments
of the lower part of the belly, and a short time
after it gets there, the foetus is found attached
by its mouth to one of the nipples of the
mammae, which are concealed within the mar-
supium. The young of the marsupiate animal

* Under the head of OVUM we shall shew that
all animals undergo changes which constitute me-
tamorphoses of one kind or other during their for-
mation or development.

t See the interesting papers by Mr. Owen on
the Generation of the Kangaroo and Ornithoryn-
chus in the Philosophical Transactions, part ii.
for 1834, p. 333, and in the Transactions of the
Zoological Society, vol. i. p. 221.

GENERATION.

437

there receives its food by the mouth and is
nourished by digestion at an early period of its
advancement; and, although its external form
and organization very much resemble that of
the foetus of other mammiferous animals at a
similar stage of their advancement when they are
still confined to the uterus of the mother, their
internal organization undergoes at the time of
their exclusion the same remarkable changes
which occur at birth, and which are connected
with aerial respiration and the independence of
the vital functions.*

Monotrematous generation. — The generation
of the Ornithorynchus and other monotrema-
tous animals deserves also to be noticed here
as differing in some respects from that of other
Mammalia; but, unfortunately, this subject,
which has been involved in obscurity ever since
the first discovery of these remarkable animals,
notwithstanding that several important facts
have been recently ascertained, cannot be con-
sidered as completely understood. The Orni-
thorynchus and Echidna were long regarded as
holding an intermediate place in respect to
their organization between Mammalia and
Birds. The existence of mammary glands was
denied by the first dissectors of these animals ;
and from this circumstance principally, toge-
ther with the analogy in general structure al-
ready alluded to, the Ornithorynchus was be-
lieved by many to be oviparous. The recent
investigations of Owen have proved the ex-
istence of mammary glands as well as the
suckling of the young, while they at the same
time shew that the generative organs and the
ova within the ovaries partake in a great degree
of the oviparous structure.t In this approach
to the oviparous type, however, it has been
satisfactorily shewn that the Ornithorynchus
resembles the class of Reptiles rather than that
of Birds. The ova of this animal have not, how-
ever, been found in any of its haunts ; and,
although no one has yet had an opportunity
of dissecting the gravid uterus, naturalists are
now inclined to hold the opinion that it bears
its young alive. Should this be fully proved
to be the case, the Ornithorynchus may with
justice be considered as an example among
mammiferous animals of the ovo-viviparous
form of generation, most analogous to that
occurring in the Slow-worm or Adder; the
ovum being, at the time of its descent into the
oviduct, of proportionally large size, and there
being no proper placenta or intimate organic
union between the mother and foetus.

Comparison of animal and vegetable repro-

9 For the details respecting the structure and
functions of the generative organs of the Marsu-
piata, the mode of passage of the embryo from the
uterus to the pouch, see the article upon the Com-

Farative Anatomy of these animals, MARSUPIATA.
t is curious to note that until the discovery of
the uterus of these animals by Tyson, the vaguest
conjectures prevailed respecting their mode of
reproduction, it being even supposed by some that
the foetus grew from the first attached to the nipple,
and consequently originated as a bud.

t The name of Monotremata applied to these
animals, it may be remarked, means with cnievent,
they having a cloaca.

duction. — In concluding this rapid sketch, it
may not be out of place to introduce here a
few remarks upon the analogies existing be-
tween animal and vegetable reproduction.

The seed of plants is generally regarded as
corresponding to the egg of animals. The
seed and egg correspond in being both the
residence of the germ or living part from
which the new organized body springs, and
also in both containing a certain quantity of
matter destined for the temporary nourishment
of the growing embryo ; but the germ is in a
different state in the seed and egg ; for while
in the egg none of the parts of the new being
are visible at the time of its separation from
the parent, the rudiments of the embryo are fre-
quently to be found, small but simulating in some
degree the plant, in the germ of the seed when
it is perfected, and before the commencement
of germination. The circumstances favourable
to evolution give rise to the development of
the embryo in both, but in the animal the
influence of the male conferring fecundity on
the egg makes no perceptible alteration in the
germ, while in the plant no part of the seed,
neither cotyledon nor germ, is formed unless
fecundation by the pollen of the male takes
place ; and the seed is not separated from the
ovary or place of its production until the
rudimentary parts of the embryo are already
sketched out.

We have examples of non-sexual repro-
duction of plants among the Cryptogamia, in
which the new plant springs from sporules or
granules endowed with the independent vital
properties of the seed.

The greater number of monocotyledonous
and dicotyledonous plants may be regarded as
hermaphrodite, as both the seeds and pollen
are formed on the same individual, while in
others the position of the sexual organs on
distinct individuals corresponds with the more
common arrangement in the animal king-
dom.*

In different tribes of plants we also observe
examples of occasional propagation in a man-
ner different from the more common one by
seeds or sporules. Thus the buds and branches,
which are the means of their ordinary growth
and increase, may,when removed, be capable of
independent existence and give rise to distinct
plants, or even when still on the parent stock
may take root and grow anew. Some buds
separate naturally and are evolved in the man-
ner of seeds when placed in favourable circum-
stances ; and in a third class of instances sepa-
rated buds are preserved in the collections of
nutrient matter constituting the tuberous and
bulbous roots by which many plants are pro-
pagated.

To complete the enumeration of the points
of analogy between animal and vegetabl-e re-
production, it may be stated that there is the
same reason for believing in the spontaneous
generation of some of the Cryptogamic plants
as in that of Infusorial animals.

* As in strictly Hermaphrodite, Monoecious, and
Dioecious plants.

438

GENERATION.

The following table is intended to exhibit a
synoptical view of the various forms of the

reproductive process
classes of animals.

occurring in different

Non-sexual . . .

Fissiparous . . .

Gemmiparous .

{

Hermaphrodite.

Sexual

Dioecious.

III. REPRODUCTIVE FUNCTION IN MAN AND
THE HIGHER ANIMALS.

1. Sketch of this function in man. — In now
proceeding to a more detailed account of the
function of generation, our description must be
confined to the process of reproduction in the
human species and in those animals which are
most nearly allied to man.

The following may be mentioned as the
principal steps of the reproductive process in
the female of the human species.

The human offspring is derived from an egg
like that of all the more perfect animals. The
egg is gradually formed in the Graafian vesicle
of the ovary at the period of maturity. In
productive sexual union the vagina and uterus
receive a certain quantity of the male seminal
fluid, and a series of changes are induced in
the female generative system which have the
effect of dislodging one or more ova from their
residence in the ovary, and of bringing these
ova into contact with the seminal fluid, in
order that they may be fecundated or rendered
fruitful. The mechanism of the discharge of
the ova is the following. The Graafian vesicle
swells, and bursts at its most prominent part.
The ovum escaping from its interior is received
by the fimbriated cavity at the commencement
of the Fallopian tube, along which tube it
gradually passes until it reaches the interior of
the uterus, where it arrives probably in ten or
twelve days after sexual union. There is every
reason to believe that before the ovum reaches
the uterus it has already been exposed in some
part of the genital organs to the influence of
the male semen, and that it is consequently
fecundated. \\e shall have occasion after-
wards to inquire more minutely into the place
and manner of this fecundation. The female
is now said to have conceived or to be impreg-
nated, and the ovum to be fecundated. We
shall endeavour, for the sake of clearness, to
bring the history of the steps of this process

Parent splits, each part a new animal.

1. Transverse.

2. Longitudinal.

3. Irregular.

Parent splits and discharges the young.
Budding upon the parent stock.
Separated buds. Gemmae or sporules.

1. On all parts of the body.

2. On one part or organ only.
Both sexual organs on one individual.

1. Self-impregnation.

2. Mutual impregnation.
Oviparous, laying eggs which are hatched.

1. External fecundation.

2. Internal fecundation.
Ovo-viviparous. Eggs hatched within the

maternal body.
Mammiferous, suckling the young.

1 . Monotrematous.

2. Marsupial.

3. Placental or strictly vivi-

parous.

under the three distinct heads of, first, the
changes of conception as regards the female,
secondly, the process of fecundation as relating
to the male, and thirdly, the effects of the union
of the male and female product.

Before the ovum reaches the uterus a change
has already commenced in the interior of that
organ, which in its farther progress has for its
object to bring about an organic union between
the uterus and the foetus with its coverings. The
minute embryo soon becomes visible in the
ovum, has envelopes formed over it which
become connected with the lining membrane
of the uterus, and as it advances in growth
continually receives a supply of nourishment
from the bloodvessels of the uterus. It is
nourished in this way during the whole of its
intra-uterine life, at the termination of which
the child is brought into the world or born,
being expelled from the uterus by those pain-
ful efforts and contractions of the uterus con-
stituting parturition or labour. The child is
now capable of being nourished by digestion
of food in the stomach, independently of
any organic connexion with the mother, and
breathes air by its lungs. Although all or-
ganic connexion, however, between the mother
and child is now dissolved, yet the infant is
for a time dependent on the mother for nou-
rishment, receiving by sucking from the mam-
ma; the milk, which it assimilates by its own
independent powers. In the present article
our object is to describe only the processes of
conception and fecundation, referring to the
article OVUM for an account of the growth of
the foetus, and to the articles UTERUS, OVARY,
&c. for the more minute anatomical and
functional relations of these organs in the
unimpregnated and impregnated states.

Organs of reproduction. — The organs of
reproduction in both sexes are frequently divi-
ded by anatomists into external and internal,
according as they are situated more or less near

GENERATION.

439

the surface of the body ; hut a more suitable
arrangement of these organs in a functional
point of view is that which is founded on the
part which each of them is destined to perform
in the generative act. The male organs consist
of the penis and urethra, testicles, seminal vesi-
cles, seminal ducts, prostatic body , and Cowper's
glands: the female organs, of the vulva, clitoris
and nymphse, vagina, uterus, Fallopian tubes,
and ovaries. The testicles in the male and the
ovaries in the female are the productive organs,
secreting or forming by an organic process the
product of each respective sex ; the vasa defe-
rentia and vesiculae seminales conduct and
retain for a time the seminal fluid ; the Fallo-
pian tubes conduct downwards the ovum from
the ovary to the uterus ; the uterus receives
and retains the ovum during pregnancy or the
formation of the child. These constitute the
internal organs ; the remaining parts are the
external organs, and are chiefly connected with
sexual union or the expulsion of the products
from the body. The glans penis, the clitoris,
and the neighbouring parts are the seat of that
feeling which accompanies the venereal act:
the penis, with its urethra, serves to conduct
the seminal fluid into the vagina and uterus of
the female : the vagina, besides receiving the
seminal fluid, is the issue for the child when
it is expelled from the uterus in parturition.

Puberty. — It is only during a stated period
of life that animals are capable of reproduction.
In infancy, youth, and old age the functions
of the sexual organs are in abeyance. The
name of puberty is given to that period of life
at which either sex first becomes capable of re-
production, at which time various important
structural and functional changes occur both
in the sexual organs and in the whole eco-
nomy.

These changes are upon the whole more
marked in the female than in the male, a cir-
cumstance which may be attributed to the
longer and more intimate connexion of the
female with the product ; the maternal parent
affording a supply of nourishment to the child
during the whole of its intra-uterine life, while
the male does no more than furnish momenta-
rily a small quantity of the seminal fluid
necessary for fecundation.

Structural differences of the sexes. — In in-
fancy and youth the two sexes do not differ
materially in the general shape of the body,
nor in physical powers ; but as the age of
puberty approaches, and the sexual organs
undergo those changes which fit them for the
performance of their appropriate functions, the
male and female bodies become altered in
form, and acquire a more marked difference,
while the mental and physical powers also par-
take of this discrepancy.

We shall do no more than mention here the
most striking of these peculiarities, as a more
detailed account of them belongs to another
place.

Besides these differences which belong im-
mediately to the sexual conformation, the com-
paratively broader shoulders and wider chest
of the male, and the larger pelvis and ab-

domen of the female, are universally known
as constituting the chief peculiarities in the
general contour of the body. The smaller size
of the whole body in the female, amounting
in general to a tenth of the whole height, the
greater slenderness of the female frame, the less
prominence of the muscles, the more tapering
and rounded shape of the limbs, the greater
quantity of fat under the skin and elsewhere,
the smaller, smoother, and finer bones, and
the more delicate texture of some other parts
of the body, are all peculiarities of female
conformation contrasting with the opposite
qualities in the male body. As belonging
to the male may be mentioned the low and
rough voice from the larger size of the larynx
and longer vocal cords,* the occurrence of
hair on the chin, upper lip, and cheeks, as
well as over the body and limbs, in which
situations it is rarely met with in the female,
the greater physical power and activity, capa-
bility of enduring fatigue and daring, &c.

As these changes in either sex are gradually
developed, hair grows on the skin covering the
symphysis pubis, in the neighbourhood of the
genital organs, t and later under the axillae.

The local changes attendant upon puberty
in the male are the enlargement of the penis,
its more frequent erection, and accompaniment
of this by the sexual feeling ; the enlargement
of the testicles, vesiculae seminales, prostatic
gland, and other accessory parts; the more
depending condition of the testicles in the
scrotum ; the secretion of a certain quantity
of the seminal and prostatic fluids ; and, after
the attainment of the full sexual powers, the
occasional spontaneous emission of some of
the seminal fluid, occurring in general at night
during sleep, and being accompanied by some
sexual feeling in dreams.

In the female at this period, both external
and internal organs undergo a considerable
and rapid enlargement ; the mons veneris and
external labia become more full ; the clitoris
and nymphae in many, but not in all, become
susceptible of a certain degree of swelling or
erection ; the breasts enlarge, the vesicles in
the ovaries become dilated, and some of them
more prominent, and there is established a
periodical discharge of a certain quantity of a
sanguineous fluid from the internal genital
organs.

Menstruation. — This periodical loss of blood
demands the attention of the physiologist as
one of the most remarkable of the sexual pecu-
liarities of the human female, and as bearing
an intimate relation not only to the generative
process, but to most of the other functions of
the economy.

The periodical recurrence of the discharge of
blood every lunar month or twenty-eight days

* Comparative measurements have been made
of the length of the vocal cords in boys imme-
diately before and after puberty, and those of the
young men liave been found to be nearly double the
length of those of the boy.

t Hence the name of this bone and of the period
of Hie of which we are now speaking — pubes and
puberty.

440

GENERATION.

has given to it the name of menses or men-
struation : the Greek word catamenia is also
employed to denote it by medical men, and
the English expressions of " the illness" or
" the courses" are those in most common use
among the vulgar.

The menstrual flow of blood lasts usually
for about five days, beginning and leaving
off gradually, and being in greatest quantity
towards the middle of the period. The in-
terval is thus generally about twenty-three days.
The discharge in general takes place slowly, or
drop by drop.

The menstrual flow of blood is preceded in
most women by some symptoms of fever, a
quicker and fuller pulse than usual, languor,
headach, pains in the back, and frequently in
the hypogastria or region of the ovaries, and
by many other symptoms of general derange-
ment of the functions, particularly in weak or
unhealthy women. In young women upon
the occasion of the first appearance of the
menses all these symptoms are frequently more
strongly marked.

Menstruation may be regarded as the most
certain sign of the arrival of puberty, and of
the fitness of the human female for marriage,
as there are very few instances on record in
which conception has taken place before the
occurrence of the menstrual discharge. It
continues for the whole of that period of life
during which women are capable of bearing
children; and after this, when it ceases, a
considerable change in the female constitution
ensues : the " change of life " or " critical
period " is said to have arrived, from the liabi-
lity there then is to the conversion of the
plethoric state, previously relieved by men-
struation, into some morbid affection either of
the sexual or other organs of the body.

During menstruation, the uterus, vagina,
ovaries, and other parts of the genital organs
are usually more vascular and turgid with
blood than in the interval; the mamma, which
exhibit at all times a remarkable sympathy
with the condition of the uterus, frequently
participate in this increased activity at the
menstrual period, as they then swell and be-
come hard.

Menstruation consists essentially in the
exudation of a fluid resembling blood from
the female genital organs, and principally from
the uterus. Haller states that the blood has
actually been observed to proceed from the
uterus in women labouring under prolapsus
of that organ, and John Hunter as well as
others have found the cavity of the uterus filled
with the fluid in women who have died during
menstruation.

Menstruation usually ceases during pregnancy,
and in the majority of women during lactation
also. In those instances in which the monthly
flow has continued to take place during preg-
nancy, there is reason to believe, according to
Haller, that it may have proceeded from the
upper part of the vagina, as the first changes
attendant upon utero-gestation usually close
firmly the neck of the uterus.

The quantity of fluid which exudes during

one menstrual period amounts in general to
five or six ounces; but this is subject to great
variation from the mode of life of the indivi-
dual, state of her health, diet, and other
circumstances. The quantity is usually greatest,
cseteris paribus, in healthy women living well,
but the increase of the quantity above a certain
point or its diminution below another are
equally to be regarded as unnatural or diseased
states of the action. In tropical countries the
quantity is greater than in more temperate
regions, amounting occasionally to twelve or
even twenty ounces. In Lapland and some
other northern countries the quantity is, on the
other hand, much below the mean, being
occasionally as low as three ounces ; and yet
in both these situations the women are to be
regarded as within the bounds of health.

The quantity of fluid lost in menstruation is
increased by all those circumstances which cause
a determination of blood to the pelvis or its
contained viscera; hence the effect of posture,
irritating diuretics, drastic purgatives, and those
medicines termed emmenagogues.

The nature of the fluid discharged in men-
struation has not yet, we believe, been investi-
gated with sufficient accuracy. It bears a close
resemblance to blood, having generally the
colour of the venous kind. It is generally
fluid, but sometimes coagulates from exposure
to air : it is generally believed to contain less
fibrine than blood, and to be less prone to
putrefaction.

Respecting the causes of the menstrual dis-
charge and its uses in the economy, many very
absurd hypotheses have been advanced in me-
dical writings. It was a common belief among
the ancients that the menstrual fluid exerted a
baneful influence on every living object, plant,
or animal, and many of the institutions and
laws of antiquity shew that this natural process
was looked upon with abhorrence. The corres-
pondence in the length of time of the moon's
changes with the recurrence of the menstrual
period induced many to believe in an influence
exerted by the moon on the female generative
system ; but the error of such a notion is suffi-
ciently proved by the circumstances, first, that
more women are not found to menstruate at one
period of the moon's changes than at another,
and, second, that the women of any place men-
truate at all different times. Besides this, many
women do not menstruate regularly every lunar
month. In some this change takes place
every three weeks, in others every fortnight,
and there are many in whom there is a varia-
tion of one or two days on either side of the
common period of twenty-eight days.

When we consider the circumstances pre-
viously mentioned respecting the intimate con-
nexion subsisting between the menstrual flow
and the processes of reproduction, we shall be
led rather to the opinion that menstruation is
to be regarded as a means of relieving the
female system periodically from an overplus of
blood which exists during the whole of the
time in which it is capable of propagation. It
occurs at this period of life only, it generally
ceases during pregnancy, and it may therefore

GENERATION.

441

correctly be regarded as the indication of the
presence in the system of that quantity of
nutrient matter, which, during pregnancy, is
destined to serve for the nourishment of the
child. We say that this flow does no more
than indicate the surplus quantity of blood in
the female genital organs ; for, as Burdach
remarks, the loss of six ounces of blood for
ten successive lunar periods amounts to only
three pounds twelve ounces, whereas the foetus
and its appendages during that period attain
the weight of from ten to fifteen pounds, to
which we might add the enormously increased
weight of the uterus in order to estimate the
whole addition which is made to the uterine
system during pregnancy. Again, during lac-
tation or nursing the tendency to a super-
abundance of blood or plethora in the uterus
is generally relieved by the flow of milk from
the mammae, which, as has already been
remarked, sympathize very constantly with the
uterus and other parts of the generative system.

Such a tendency to plethora as that we have
just alluded to, it is scarcely necessary to remark,
can have no connexion with lunar or planetary
influences, and we are, perhaps, more justified
in classing it along with those other changes of
the economy which indicate a remarkable ten-
dency in the human constitution to periodical
recurrence of its actions.

The crises of fevers on days terminating
periods which are most frequently of the dura-
tion of seven, fourteen, twenty-one, or twenty-
eight days, are of this kind ; and it is deserving
of notice that menstruation recurs more fre-
quently in periods, the number of days of
which are multiplies of seven, than in any
others.*

It has been attempted to be shewn that the
male is subject to a periodical plethora in some
respects similar to that which gives rise to
menstruation in the female, but without any
just reason, unless we choose to consider as
such the gradual accumulation of seminal fluid,
which frequently takes place in healthy men of
sanguine temperament, and which gives rise
to its periodical emission.

With regard to menstruation we shall only
farther remark that, according to Haller, Bur-
dach, and some others, women are more liable
to become pregnant immediately or within a
few days after the cessation of menstruation
than at other parts of the interval ; the probable
reason of which will appear from details given
in a subsequent part of this article.

Periodical heat in animals. — None of the
lower animals in the natural state appear to be
subject to anything like a menstrual change or
periodical discharge of blood. In lascivious
Apes and in some of the domestic animals fed

* According to the researches of Mr, Roberton of
Manchester, detailed in an interesting paper, pub-
lished in the Edinburgh Med. and Surg. Journal,
vol. xxxviii. p. 237, out of 100 women, in sixty-eight
the menstrual discharge returned every fourth week ;
in twenty-eight every third week ; in one every se-
cond week ; in ten at irregular intervals. These
varieties usually exist as family and constitutional
peculiarities.

VOL. II.

highly, an exudation of bloody mucus from
the vagina and external genital organs of the
females sometimes occurs, but this is manifestly
quite different from menstruation. There is,
however, in most of the lower animals a very
obvious periodicity in the functions of the
reproductive organs; for while the human
female is, during a certain period of life,
nearly equally fit for propagation at all times,
this is the case with very few animals, and,
indeed, chiefly among those living in the un-
natural state of domesticity.

At certain seasons of the year there occurs
in most of the lower animals a determination
of blood to the genital organs of the female,
accompanied by sexual desire, which leads
them to the propagation of their species. This
state of excitement, generally named " the
heat,"* lasts for a longer or shorter period; in
the ewe for twenty-four hours only, in the
cow and mare for a few days, in the bitch
nine or ten days, and in the hen-pheasant for
as long as two months. In most animals, after
it has run its accustomed course, it disappears
naturally, but it is more certainly and sooner
dispelled by fruitful sexual union.

The heat belongs more properly to the female
than to the male, as there are many species
whose females receive the male only at par-
ticular seasons, while the male is at all times
fit for propagation. In others, constituting the
majority of instances, the male organs are sub-
ject to the same periodical increase of activity
as the female. The male in these animals is
usually in heat at an earlier period than the
female.f

In some animals there is a more frequent
periodical return of the heat than in others;
thus the ewe which remains unimpregnated
comes in heat every fourteen days; the cow
and some apes, the mare, ass, and buffalo
every four weeks; the sow every fifteen or
eighteen days ; but in these animals the high
feeding attendant on domesticity may very
probably occasion a more frequent and less
natural return of the period of heat than would
occur in the wild state.

It would appear that the season of the year
at which animals most commonly breed is
subject to very many and extensive variations,
according to the temperature, latitude, and
other circumstances connected with the country
which they inhabit.

During the continuance of the heat a peculiar
odour is exhaled from the genital organs, and
there exudes chiefly from the external organs
some bloody mucus, which, in some lascivious
apes, resembles blood so much as to have
given rise to the belief already alluded to that
these animals menstruate.

Age at which puberty occurs. — The appear-

* Termed the Rut in the deer, wild boar, &c.

t In some male animals the signs of heat are
very apparent. The fine colour of the plumage of
most male birds in the breeding season, the deep
colour of the comb, &c. in gallinaceous fowls, the
thickness and bushy hair of the deer's neck, the
greatly enlarged size of the testicles in the cock-
sparrow, may be mentioned as familiar examples.

2 G

442

GENERATION.

ance of puberty is gradual in both sexes, but,
upon the whole, more slow in the male than
in the female. The age at which it takes place
varies in the same and in different countries
according to the mode of life, physical and
moral education, and other circumstances. It
takes place at an earlier age in woman than in
man : in the former most frequently in this
country at from the age of thirteen to sixteen
years, in the latter from fifteen to eighteen
years; but instances are not unfrequent of
girls menstruating and of boys passing into
manhood one or two or even more years sooner
or later than the above-mentioned periods, as
from ten or eleven to twenty or twenty-two
years.*

These variations are to be considered as
dependent on constitution in the greater num-
ber of instances; but in respect to their
occasional causes, it may be stated that all
those circumstances which produce a determi-
nation of blood to the sexual organs or pelvic
viscera, which relax the body generally, or
turn the attention of the young to the sexual
function, tend to bring on sooner than natural
the local changes of puberty. Warm rooms,
a sedentary mode of life, particular kinds of
reading, and some bad habits are all hurtful in
this respect.

According to the observations of many tra-
vellers, puberty arrives sooner in warm than
in temperate climates ; and some have hence
too hastily concluded that the warmth of the
tropical country has been the cause of the more
precocious appearance of menstruation in wo-
men and puberty in men, an opinion the error
of which is shewn by the fact that instances of
very early puberty are not unfrequently met
with in high northern latitudes .f The occur-

* Accord'ng to Mr. Roberton's observations pre-
viously quoted, the following are the ages at which
450 women began to menstruate :

In their llth year 10 women.

12th
13th
14th
15th
16th
17th
18th
19th
20th

19
53
85
97
76
57
26
23
4

This table shews that the age of puberty of females
in this country extends over a considerable number
of years, and is more equally distributed than is
commonly alleged.

t The opinion that menstruation happens at an
earlier age in warmer climates is very generally enter-
tained, as may be seen by a reference to the works
of Haller, Boerhaave, Denman, Burns, Dewees,
and others. Mr. Roberton has successfully shewn
its inaccuracy by an appeal to the facts stated by
modern travellers, as Hearne, Franklin, Richard-
son, and Back with regard to the Northern Cana-
dian Indians; by Lyon and Parry with respect to
the Esquimaux ; by Clarke in reference to the
Laplanders ; and by Tooke in relation to the
Northern Russians; all of whifh shew that puberty
is attained in the arctic regions at least as early
as in more temperate climates. On the other hand,
from the evidence of Crawford and Raffles relative
to the inhabitants of the Indian Archipelago, of
Messrs. Ellis and Browne (missionaries) in regard

rences of marriages, therefore, or sexual union
at the early age of six or seven years in the
South Sea Islands and elsewhere is to be looked
upon rather as a proof of the barbarous and
debased state of civilization of these people,
than taken as an evidence of their being fitted
by nature for the functions of propagation at
the period of life now mentioned.

There do sometimes occur, however, in all
nations unfortunate examples of precocity in
the development of the sexual organs and
activity of their functions. Thus in male or
female children of four and even of only three
years old all the changes of the sexual organs,
and some of those of the body generally, which
belong to puberty of a more advanced and natural
age, take place. The attention of such children
is soon called by their local feelings to the
condition of the sexual organs, and vicious
habits are induced, which, from the misery
they carry along with them, it becomes the
duty of the medical man to counteract by all
the resources of his art.

Period of' life during which the generative
function is exercised. — The length of time du-
ring which the male and female of the human
species retain the power of propagation is sub-
ject to the same variations which attend the
arrival of the age of puberty. The most healthy
women are in general capable of bearing chil-
dren between the ages of fifteen and forty-five,
or for a period of thirty years. Men retain the
powers of their sex for a longer time, as from
the age of seventeen to sixty or seventy, that is,
for forty-five or fifty years. There are, however,
on record instances of both sexes, but more
especially the male sex, having retained their
respective powers for a longer period than that
just stated ; — of women menstruating a second
time (after the cessation of this function at the
usual period) at the age of sixty or seventy,*
and in one or two instances bearing a child at
that advanced age; — of propagation in the male
sex to the age of seventy, eighty, and ninety,
and in the celebrated case of old Parr even to
that of one hundred and thirty years. f

Among the lower animals the variations in this
respect are so numerous as to preclude the pos-
sibility of our mentioning even the more im-

to those of Polynesia ; of Dr. Winterbottom on
the native Africans round Sierra Leone; of the
laws of the Koran in regard to the Arabs ; and of
the observations by Russel on the Egyptians, Mr.
Roberton endeavours to prove that though early
marriages are common in warm and equinoctial
countries, yet the period of puberty and of the
capability of procreating is nearly the same as in
temperate and northern latitudes. Mr. Roberton
is therefore induced to form the conclusion that the
variations from the standard or more common
period of puberty in different nations are not greater
than the individual differences to be observed in
our own country, and that the opinion above
referred to ought to be looked upon as a vulgar
error.

* These instances are very rare indeed. Mr.
Roberton states that of 3000 women delivered in the
Manchester Lying-in Hospital, only one was above
fifty years of age.

t See Haller's Elementa for an enumeration of
such examples.

GENERATION.

443

portant in this place. The male of some in-
sects, it is well known, die as soon as they have
fecundated the female ; many plants and ani-
mals propagate only once, while others give
rise to many successive families ; but we are
not acquainted with any general law to which
such differences can be referred.

Effects of castration. — Nothing illustrates in
a more striking manner the intimate relation
which the sexual function bears to the general
organization and functions of the body than the
effect of castration, or the removal of the forma-
tive and essential parts of the sexual organs in
either sex. \Vhen both the ovaries or testicles
have been removed or destroyed, the power of
propagation is of course entirely lost. When
this operation is performed at an early age,
there is also caused a remarkable alteration of
the constitution and general habit of body of
the animal. The functional and structural pe-
culiarities of the body become less marked, and
there is a great tendency in general to the uni-
versal deposition of fat in different textures.

In the castrated male, the form and texture
of the body approaches that of the female, and
the mental faculties seem to partake in a certain
degree of a similar modification. The voice
remains high and clear • and hence the barba-
rous custom prevailing to the present day in
Italy and elsewhere of making eunuchs for the
sake of their high voices in singing.

In the spayed female, on the other hand,
there is a certain approach to the characters of
the male. In women in whom it has been
necessary to extract the ovaries on account of
disease, the bones and muscles have been ob-
served to have a more masculine contour, the
voice is harsh like a man's, the breasts are flat,
and there is frequently a formidable beard, and
hair on different parts of the body.

The same or similar circumstances have been
remarked in those unfortunate malformed indi-
viduals who present an approach to hermaphro-
dite formation, or in whom there is imperfect
development of either the male or female geni-
tal organs. So also it has been observed that
the females of some animals, as the sow, phea-
sant, and pea-hen, and even the human species,
when the period of life for propagation is
passed, assume some of the male characteris-
tics, such as the plumage in the birds men-
tioned, bristles in the sow, &c.

It is well known that the annual change of
the horns in deer is intimately connected with
the generative function. Mr. J. Hunter first
shewed by experiment that when the deer are
castrated while the horns are complete, they
remain permanently and are not changed as in
the natural condition ; and that, if the opera-
tion be performed when the horns have fallen,
they will not again be renewed.

The operation of castration, particularly when
it is not performed till late in life, while it pro-
duces complete sterility in the female and im-
potence in the male, does not entirely destroy
sexual desire, for eunuchs and the castrated
males of many animals are known to be lasci-
vious. Some writers would even have us believe
that it is possible for the power of propagation

to remain in the male after castration. These
cases appear extremely doubtful, and, even ad-
mitting the truth of the statement that a cas-
trated male has propagated, this by no means
invalidates the statement that the removal of
the testicles has destroyed all productive power,
because it is possible that some seminal fluid
may have been retained in the seminal vesicles
and vasa deferentia. The operation does not
prevent the erection of the penis or venereal
orgasm from taking place; consequently the
act of sexual union, and even some emission of
fluid from the vesicula? seminales and prostatic
body, may occur in the castrated animal ; and
in some kinds of animals, it may further be re-
marked, that the union of such males with the
females, though altogether unproductive, is
attended with several of the more important
changes which belong to fruitful sexual union,
such as the excitement of the internal organs of
the female, the discharge of vesicles from the
ovary, and the formation of corpora lutea.

The removal of one testicle or ovary only
does not appear to be attended with any change
in the sexual or other functions ; and it appears
to be equally inconsistent with fact, that those
originally provided with only one of these
essential organs, are endowed with less procrea-
tive power than others, as that those who are
said to have had more than the usual number
are remarkably salacious or fertile.

3. Sexual feeling. — In all animals in which
the distinction of sex exists, the first act of the
generative process or the union of the sexes is
insured by instinctive feelings experienced by
both of them in a greater or less degree.
These feelings generally depend upon the con-
dition of the body, and in particular of the
genital organs, which at the time of pro-
pagation are in a greater than ordinary state
of excitement. From the increase of peculiar
secretions, at the breeding season, the odour of
the genital organs of animals becomes stronger
than at other times, and seems to have a very
direct effect in exciting the sexual appetite.
These feelings are in the greater number of
animals strongest in the male, and he conse-
quently generally seeks the retiring female;
but in other instances the reverse is the case.

In the human species also, similar feelings
exist, but under the control of the intellectual
and moral powers of the mind. Hence the
immense variety we observe in the effects of the
exercise of the sexual passions on different peo-
ple, and hence the various modifications which
they undergo from the state of civilization
among different nations; on the one hand
being productive of scenes and habits of dis-
gusting obscenity among those barbarous peo-
ple whose propensities are unrestrained by
mental cultivation ; and on the other, attended
by social ties and higher intellectual ideas
among those in whom, from education and the
cultivation of the mind, the bodily appetites or
passions, subject to the reason, assume a milder,
less selfish, and more elevated character. Hence
it comes that the various customs of different
nations, legislative enactments of ancient and
modern statesmen, and even some religious in-
2 G 2

444

GENERATION.

junctions and ceremonies relating to marriage
arid concubinage, are to be regarded rather as a
picture of the state -of civilization among the
different people to which they have belonged,
and as the result of local situation and circum-
stances, than a consequence of their physical
organization or natural endowments, as some
would have us to believe. But the considera-
tion of these modifications in the customs and
habits of different nations belongs more appro-
priately to the province of the political econo-
mist than of the physiologist.

4. Relation of' reproduction to the brain. —
In how far the sexual feelings just spoken of,
and the reproductive function as a whole, are
connected with the brain or any of its parts, we
leave to be discussed by others. We shall only
remark in this place respecting this connection,
that the mental feeling and local affection rela-
ting to sex are very intimately associated toge-
ther; on the one hand, the local irritation of
the genital organs exciting mental desire, and
on the other, the erection and other signs of
affection of the sexual organs being immediately
caused by all those ideas and passions of the
mind which bear a relation to sex. In the
same manner as the action of the heart, the flow
of the blood in some of the bloodvessels, the
processes of digestion, respiration, and secre-
tion are modified by mental emotions, the sexual
function may be regarded as subject to their
influence, and consequently subject to modifi-
cation from the condition of the mind or brain.

In the phrenological system, as is well
known, it is held that the cerebellum is
that particular part of the encephalon which
presides over the sexual function, — in other
words, that sexual feeling belongs to the cere-
bellum as its sensorium commune, to which
impressions of a sexual kind proceed, and from
winch -emanates sexual desire, as well as the
influence under which the reproductive organs
execute their appropriate functions. The proofs
alleged in favour of the phrenological hypothesis
are principally of the following kind : 1st, that
the back of the head and neck, and particularly
the cerebellum, is largest in those of the human
species who shew much sexual love, and among
animals in those in which sexual feeling and
productive power are greatest; 2d, that local
affections of the genital organs, and variations in
the degree of sexual desire, frequently coincide
with congenital deviations from the natural
form and structure of the cerebellum, and
morbid organic changes of that organ, such
as inflammation, suppuration, effusion, tu-
mours, and softening, or violent injuries, such
as wounds producing the destruction or re-
moval of portions of the same part of the
brain.* W« leave to others the examination
of the truth of this view, observing merely
that we are not inclined to adopt the hypo-

* The proofs of the connection of the cerebellum
with the sexual function may be more fully stated
as follows:

1st. The coincidence of barrenness or impotence
with hydrocephalus, ramollissement, suppuration,
or wounds of the head, and in particular of the
back part and cerebellum.

thesis as already established upon sufficiently
accurate or extensive data ; and we would re-
mark that the comparative anatomy of the
brain (in which, rather than in experiments on
animals, we should feel disposed to place much
reliance, from the acknowledged difficulty
of making correct deductions as to function
from the effects of morbid alteration or artificial
injury of the encephalon) affords very few argu-
ments in favour of the view now alluded to, and
furnishes several facts which militate strongly
against it.

5. Distinction of species. Mules. — The in-
stinctive feelings which lead to the union of
male and female animals of the same species
may be looked upon as one of the means pro-
vided by nature for the distinct preservation of
each specific race. So general indeed is the
law that animals of one species propagate with
one another only, that, as we already remarked,
this circumstance alone has been adopted by
some as the true specific character. We shall
see reason, however, to doubt its sufficiency.

While the natural repugnance which the
males and females of different species or
genera have to propagate together may be
regarded as one of the most powerful means
by which the distinction of species is insured,
we must not lose sight of other circumstan-
ces which contribute to the same effect.
Among these may be mentioned, in the first
place, the unfruitf'ulness which generally attends
the union of different species when it has oc-
curred ; then the difference in the size of ani-
mals, the discordant properties of the semen of
the one and ova of the other, the difference of
season at which nearly allied animals come
into heat, as well as many other circumstances
which put a bar to the extension of races by
promiscuous propagation of species or genera.

In the state of domesticity, however, this,

2d. The coincidence of excited states of the re-
productive organs, as priapi«m, nymphomania, and
satyriasis, with inflammation of the same parts.

3d. Instances occurring in birds (mentioned by
Serres) of cerebellar apoplexy from the persistence
of unsatisfied sexual desire.

4th. Coincidence of cerebellar apoplexy, inflam-
mation, &c. and diminution of the sensorial power,
with over-exertion of the sexual powers, excess in
venereal pleasures, &c,

5th. Large size of the cerebellum or upper and
back part of the neck in those individuals among
the human species or among animals in which the
sexual desire and reproductive power are greatest.

6th. The reverse being the case in those in whom
the function is inactive ; as the small size of the
back of the neck, &c. in castrated animals.

In endeavouring to ascertain the value of this
kind of evidence adduced in favour of the phrenolo-
gical view, we must consider well the nature of the
alleged facts themselves, and weigh them candidly
against facts of an opposite tendency adduced on
the other side, such as those cases of small size or
absence of the cerebellum, in which the sexual
propensities have been highly developed, and the
converse cases ; and we must, at the same time,
not lose sight of those other experiments and obser-
vations which would tend to shew either that the
cerebellum is intimately connected with other func-
tions than the reproductive, or that the sexual
powers are influenced by the condition of other parts
of the brain besides the cerebellum.

GENERATION.

445

like other laws of the reproductive function, is
subject to some modification, and we find ac-
cordingly several allied species of the domestic
animals breeding freely together ; and there are
not wanting, even in the wild state, examples
of the mixture of distinct species.

The animal produced by the union of the
male and female of distinct species receives
the name of Hybrid or Mule, which generally
partakes of the qualities of both its parents in
a greater or less degree. Here again we find
another effectual impediment put by nature to
the mixture of different species, in this circum-
stance, that the mule, whether male or female,
is usually unfit for propagation. The offspring
of male and female of distinct species is much
more frequently fruitful than that of distinct
genera.* The instances of the former are not
few, as in the wild and tame cat, the wild
boar and domestic hog, the pheasant and
domestic fowl, the wild and tame duck.
But the instances of the latter or mixture of
distinct genera are very rare, and most of them
require confirmation. We must at the same
time always hold in mind that the distinction of
species by naturalists is at all times artificial or
made by man, how much soever he may con-
ceive his classification to be founded in nature,
and those animals which are regarded by one
naturalist as different species of the same
genus are made by others to constitute distinct
genera.

It is well known that in gardens and else-
where, although the pollen of very various
plants is almost constantly flying about through
the air, it is only among the most nearly allied
races or varieties that mixture occurs, and the
instances of the mixture of different species of
plants are very rare indeed. Many of the
mixed varieties so produced cannot be pro-
pagated by seeds ; so that there is in the vege-
table as well as in the animal kingdom a con-
stant tendency to return to the original distinct
species.

The milt and spawn of different fishes are at

* The following examples of the mixture of
species are given by Burdach, but some of them
require confirmation.

Papilio Jurtina unites with P. Jurtina.

Chrysomela JEnea. ,, C. AIni.

PhalangiumCornutum „ P. Opulio.

Cyprinus Carpio

Fringilla Carduelis

Phasianus Callus

Anas Olor

Anas Glaucion

Tetrao Tetrix.

Corvus Corone

Canis Familiaris

Canis Familiaris

Equus Caballns

Equus Cabal lus
Equus Zebra
Equus Caballus
Capra Hircus

Raua

Tetrao Tetrix
Capra Hircus
Cervus Elaphus
Ce*vus Elapus

C. CarassiusorGxbelip.

F. Canaria.

P. Colchicus.

A. Anser.

A. Querquedula.

T. Urogal'.us.

C. Comix.

C. Lupus.

C.Vnlpes.

E. Zebra.

E. Asinus,

E. Asinus.

E. Quagga.

C. Ibex.

The examples of gen ra breeding together are
much less numerous.

Bufo.

Phasianus Colchicns.

Antilopc Rupicapra.
Bos Taurus ?
Ovis Aries.

the same time floating in the same water, but
even thus brought into close union with one
another, no mixture happens. The ingenious
experiments of the celebrated Spallanzani,
who attempted to impregnate artificially the
ova of one animal with the seminal fluid
of another, and the unsuccessful attempts of
many to cause different animals to breed toge-
ther, afford still farther proofs, were they want-
ing, of the number and completeness of the
impediments which nature has opposed to the
promiscuous breeding of distinct species.

The horse and ass are caused, it is known,
to unite by man, and do not naturally do so;
and in the wild suite it is probable that the
exceptions to the general rule before-mentioned
occur only when the male is deprived of his
natural female. It seems scarcely necessary
to state that the stories of fruitful union of
either male or female of the human species
with apes or other animals, considered as au-
thentic by some authors, are entirely fabu-
lous.

In a subsequent part of this article we shall
have occasion to revert to the subject of the
mixture of races in our remarks upon the
transmission of the qualities of the parent to
the offspring.

6. Functions of the external organs of re-
production.— In addition to sexual feelings,
the state of turgescence or erection of the ex-
ternal organs by which copulation is effected,
is a more or less constant antecedent and
concomitant of the first act of the generative
process. This condition belongs more pro-
perly to the external sexual organs of the male,
and especially the penis ; but it also frequently
exists in some parts of the female organs.

The erection of the penis producing the
rigidity of that organ necessary to ensure eja-
culation or forcible emission of the seminal
fluid, consists essentially in the increased
quantity of fluid in its bloodvessels, and is
with most reason to be attributed chiefly to the
peculiar structure and inherent properties of
the tissue, so called erectile, of which it is.
mainly formed. The manner in which the-
greater accumulation of blood in the erectile
tissue is brought about is by no means suf-
ficiently clearly expkined, Two different
opinions prevail as to the cause of this phe-
nomenon ; the one> that the flow of blood is
retarded in the veins by the contraction and,
consequent pressure of certain muscles situ*-
ated towards the root of the penis • the other,
that the turgescence of erection is caused by
an altered action or condition of the blood-
vessels themselves, peculiar to the erectile
tissue, in which they are capable of admitting
and retaining a greater quantity of blood in
the erected than in the collapsed state.

We must refer to the various anatomical
articles for an account of the structure of the
erectile tissue and the organs in which it occurs.;
we shall in this place advert to those points
only which seem to bear upon the physiological
view of their function.

The glans penis, corpus spongiosum urethra,
and. corpora cavernosa penis, consist in great

446

GENERATION.

part of largely convoluted veins of conside-
rable size ; but these veins are differently ar-
ranged in the last-mentioned of these parts
from what they are in the two first : first in
this respect, that in the glans and corpus spon-
giosum urethra the tortuous veins are less
dilated and more branched than in the corpora
cavernosa ; so that it is more easy to trace their
continuity with one another ; and, second, that
in the corpora cavernosa the dilated veins are
bound together and crossed in various direc-
tions by ligamentous fibres and bands, — an
arrangement which, while it tends to obscure
the connection of one vein with another, and
causes their tortuosities to appear rather like
cells than continuous tubes, at the same time
serves to prevent their distension beyond a
certain point during erection, and thus adds
to the rigidity occasioned by the accumu-
lation of blood in the venous convolutions or
sinuses.

The mode of union of the arteries with the
veins in the erectile tissue of the penis is not
yet well known ; for, although the arteries of
the penis have been traced to very small rami-
fications, corresponding small branches of the
veins have not been observed, and conse-
quently anatomists are nearly in complete ig-
norance of the nature of the small vessels of
communication or capillaries of the erectile
tissue, and are left to conjecture only respect-
ing the means of passage for the blood from
the small arteries into the cells formed by the
convoluted veins. Professor Miiller, of Berlin,*
has lately made an important step in the in-
vestigation of this point of structure, by the
discovery of a remarkable set of little dilated
and ramified branches appended to the termi-
nal twigs of the arteries distributed on the
sides and interspaces of the venous cavities
in the penis of man and several animals;
but so far as we are aware, the exact mode
of passage of the blood from these helicine
arteries, as they have been termed from their
tortuosity, has not been detected, and the
operation of these arterial branches in modi-
fying the circulation, or their relation to the
process of erection, has not been pointed out;
it appears probable that so peculiar a piece of
mechanism must have some connection with
this process. (See ERECTILE Tissueand PENIS;
also Figs. 98 and 99, p. 146, vol. ii.)

The principal exciting causes of erection
may be referred to the following heads : —

1. Mental emotions relating to sex: in ani-
mals, odour of the genital organs, more espe-
cially in the breeding season.

2. Nervous affections. Epilepsy, convul-
sions. Inflammations of the brain, and simi-
lar affections.

3. Warmth or other local irritation of the
penis and sexual organs.

4. A full state of the testicles, their excre-
tory ducts or vesiculse seminales.

* See his Archiv. fur Physiol. &c. 1835, pp. 27
and 220, and his paper, " Ueber die organischen
Nerven der erectilen mannlichen Geschlectsor-
gane/' in the Abhand. d. k. Akad. d. Wissensch.
v. Berlin fur 1835.

5. Irritation of the parts in the vicinity of
the penis, as of the urinary bladder by stone,
riding, cantharides, savine, alcohol, &c.; of the
rectum by strong purgatives; and, in short,
every thing which irritates or determines a
greater than usual flow of blood to the pelvic
viscera or sexual organs.

6. Ligatures, and all other causes of ob-
struction to the return of blood from the
penis.

Erection is an involuntary act ; for we have
neither the power directly to produce it, nor,
when it occurs, to recall the state of collapse.
When the penis is in the state of erection,
however, the rigidity may be increased by the
voluntary exertion of the ischio-cavernosi or
erectores penis, and the acceleratores urinae
muscles ; and no doubt also by the action of
the muscles lately described by Dr. Houston*
under the name of compressores venae dorsalis
penis, to the contraction of which, and the
consequent impediment produced to the return
of blood from the penis, that anatomist has
attributed in a great measure the erection of
the organ.

The turgescence of erection begins at the
root of the penis in the corpora cavernosa, and
at the glans in the corpus spongiosum. The
glans and spongy body of the urethra may,
in general, be made to collapse by pressure,
but the corpora cavernosa cannot unless the
erectile action itself ceases. The arteries of
the penis appear to beat with more than usual
force during erection.

The phenomenon of erection is not confined
to the penis or such parts as are provided with
muscles, but occurs in all situations where
that arrangement of the bloodvessels consti-
tuting the erectile tissue is to be found. The
nipple of the mamma, the cock's comb and
wattles, and the turkey's neck are all affected
in a similar way ; and, although some circum-
stances seem to shew that erection may in
some instances be promoted by muscular con-
traction, we are inclined to adopt the opinion
that it is mainly due to an altered condition
of the bloodvessels themselves, and that it
may in some degree be analogous to the dila-
tation of the bloodvessels which occurs in
blushing, and some other local determinations
of blood.f The large size of the numerous
nerves which accompany the bloodvessels of
the penis is also in favour of this view.

In many animals the penis is furnished with
a bone which adds to its rigidity. This is the
rase chiefly among Cheiroptera, Quadrumana,
Solipeda, Digitigrada, Rodentia, Phoca, and
Cetacea. We refer to the articles on Com-
parative Anatomy for a description of the many
varieties in the form of the penis in different
animals, and their uses in the act of propa-
gation.

The texture of which the glans clitoridis
and corpora cavernosa of that body as well as
the nymphae are formed, is of an erectile kind
and strictly analogous to the corresponding

* Dublin Hospital Reports, vol. v.

t See the article CIRCULATION, vol. i. p. 672.

GENERATION.

447

parts* of the penis, to which the clitoris bears
a great similarity ; and it may be remarked
that there is also a functional analogy, as these
parts in the female sometimes undergo the
change of erection under local irritation or
venereal excitement.

The glans penis is endowed with a high
degree of sensibility, and is regarded generally
as the chief seat of venereal pleasure ; but this
also belongs to the urethra at the time of
emission. The papillous structure of the
mucous membrane covering the glans, and the
large quantity of nerves distributed on its
surface, relate to this high sensory endow-
ment.

The lower part of the vagina and the clitoris
in particular are possessed of a similar high
degree of sensibility, and in some women, but
not in all, are the seat of venereal feelings from
excitement ; but in many women such feelings
are altogether absent ; and it is most erroneous
to suppose, as some have done, that these
feelings are in either sex necessary to insure the
fecundating power of the one, or the liability
to conception of the other.

With regard to the uses of the hymen we
have no conjecture to offer.

The vagina, besides serving to receive the
penis in copulation and to conduct the seminal
fluid to the uterus, is the passage by which the
child issues in parturition.

IV. CHANGES CONSEQUENT ON FRUITFUL
SEXUAL UNION.

1. As regards the female chiefly. Concep-
tion.— The consequence of fruitful sexual union
in man and quadrupeds is the dislodgement of
one of the ova contained in the ovarium, and
the fecundation of this ovum in some part of
its passage from the ovarium, where it is formed,
to the uterus, in which the foetus is developed
from it.

In now proceeding to treat of the mode in
which these further steps of the generative pro-
cess are brought about, the following subjects
present themselves for our consideration. 1st.
What changes are operated in the internal
female organs after fruitful sexual union, and
by what means are the ova dislodged from the
ovary? 2d. What changes do the ovaries or
their vesicles undergo after the discharge of any
of the ova? 3d. What happens to the ovum
from the time of its discharge from the ovary
until the commencement of the development of
the foetus? 4th. In what part of the female ge-
nerative system is the change of fecundation
effected by the agency of the seminal fluid upon
the germinal part of the egg? and lastly, In
what does the change of fecundation consist, or
upon what properties of the seminal fluid may
it be supposed to depend ?

These topics comprehend the history of the
functions of the male and female internal gene-

* The glans penis and glans clitoridis, the nym-
phae and corpus spongiosum urethrae, and the cor-
pora caveruosa penis and clitoridis are considered
anatomically as the respective corresponding parts
in the male and female body.

rative organs, in so far as they relate to the pro-
cesses of conception and fecundation ; under
which two heads, as has been already men-
tioned, it is our intention to bring the remainder
of the facts respecting generation which come
within the limits of the present article. We
shall begin with those facts relating chiefly to
the female, or conception.

The immediate consequence of sexual union
upon the female internal generative organs is
their great excitement, and a turgescence pro-
duced by an accumulation of blood in their
vessels. When sexual union proves productive,
this turgescence lasts for some time after it has
taken place, so that in animals opened at this
time, the ovaries, Fallopian tubes, and uterus
are found to be of a much deeper red colour,
and more vascular than in their natural state.
In the female Rabbit, for example, opened
soon after coition, the internal organs are nearly
black from sanguineous congestion.

There also occurs in some of these parts a
change of position in regard to one another,
which is connected with the discharge of ova
from the ovarian vesicles. The fimbriated ex-
tremities of the Fallopian tubes are turned to-
wards the ovaries on each side, and embrace
these organs closely, so that the infundibular
opening is applied against the ovary, and must
of necessity receive the contents of the Graafian
vesicle when it bursts. In some animals the
ovary is inclosed in a sac along with the infun-
dibulum by a reduplication of the peritoneum,
so that the ovary is kept always to a certain
extent within the infundibulum ; but in other
animals in which the connection between these
parts is not of this permanent kind, there is an
equally firm union of them after copulation.
In regard to the means by which this approxi-
mation and union of the fimbria? and ovaries
are brought about, it may be stated, that in
some animals the action seems to be somewhat
of a muscular kind ; for there are strong fibres,
having all the appearance of muscular fibres,
which pass from the ovary towards the fimbri-
ated portion of the Fallopian tube ; and in
these animals, as well as in others even, in
which the muscular fibres are less obvious, irri-
table contraction may be supposed to be a
means of bringing the parts nearer to one
another. The observations of Hartsoeker and
Haller, however, would appear to shew that
the vascular turgescence which follows co-
pulation, amounting to a state approaching
to erection, may also contribute to give rise
to the change of position nowT under consi-
deration, for they found by repeated trials
that the forcible injection of fluids into the
bloodvessels of the generative organs in
the human dead body caused the approxi-
mation of the fimbriae and ovaries. But,
although it may be admitted that vascular tur-
gescence may cause this approximation of the
parts, we would venture to suggest that some
power of the nature of muscular contraction is
necessary to give that degree of firmness to the
union which it is found to possess some time
after copulation.

We must remark, however, that when a

448

GENERATION.

female quadruped is opened immediately after
copulation, the fimbrise are frequently not
ob.served to be in contact with the ovary;
and this is found to be the case only when
some hours are allowed to elapse between
the copulation and the death of the animal.
Haighton never found it to have taken place
in the rabbit previous to nine hours after union
with the male, and De Graaf not even before
twenty-seven hours ; but observations of this
nature upon animals opened soon after being
killed, do not make it certain that the action
had not taken place ; for it may be supposed
that the adhesion between the infundibula
and ovaries had commenced, but was less firm
than it becomes at a subsequent period, and
that it was merely disturbed by the violence
of the death or rough handling of the body.
This is the more probable, seeing that the
same change of position has been observed to
take place before sexual union in animals in
the state of heat, as by Cruikshank in the rab-
bit, and by Haller in the sheep. In some
birds, particularly domestic fowls and ducks, it
is well known that when they are well fed all
the changes necessary for the formation of an
ovum and its discharge from the ovary may take
place without the concurrence of the male, and
in quadrupeds there is reason to believe that
the turgescence and change of position of the
generative organs above alluded to may fre-
quently occur independently of fruitful or un-
fruitful sexual union, as from excitement of the
generative organs in the state of heat, or as in
the cases observed by Haller, of ewes having
connection with wedders or castrated males
only.

There is every reason to suppose that the
same changes which we have described as oc-
curring in quadrupeds after sexual union, take
place in the same circumstances in the human
female ; that is, that the fimbriated infundibula
of the Fallopian tubes are brought near to the
ovaries, and are made to embrace them firmly,
so as, lo- -receive the contents of any vesicles
which may burst; and that this change is
produced by an action which begins usually
during sexual union, but which may also occur
•without any venereal orgasm.

The ovaries, we have already stated, become
unusually vascular during and after sexual
union; but the changes in the ovary which
most demand our attention, are those connected
with the bursting of the Graafian vesicles, and
the discharge of their contents. In the unim-
pregnated female arrived at the age of puberty,
the Graafian vesicles of the ovary are of une-
qual size. Some time after sexual union, one
or more of these vesicles, probably those which
are at the time farthest advanced, undergoes a
greater enlargement, and from its swelling pro-
jects beyond the rest of the surface of the ovary,
and after various other changes, an aperture is
formed in the most projecting part of the coats
of the vesicle, through which its contents find
an issue. But before proceeding further with
this narrative, we must recall to the recollection
of the reader the nature of the ovum, which, on
the occasion of the rupture of one of the

Graaflan vesicles, is discharged from its inte-
rior.

The ovarian vesicles of man and quadrupeds
are filled with fluid, which, viewed by the un-
assisted eye, appears to contain only a little
granular and flaky matter. This fluid is coa-
gulated by heat, alcohol, or acids, as albumen
is, and also by exposure to air. The membrane
forming the vesicle consists of two layers, an
external and internal, and the whole vesicle is
covered also by the general peritoneal and vas-
cular envelope of the ovary.

From the earliest times anatomists and phy-
siologists seem to have considered the ovarian
vesicles as the source of the offspring; and
many, from a sort of loose analogy with ovipa-
rous animals, regarded the vesicles themselves
as the ova in which the viviparous foetus is de-
veloped. The large size of these vesicles, how-
ever, as compared with the Fallopian tubes
through which the ova have to pass, and the
subsequent observations of De Graaf, Vail isneri,
and Cruikshank, as later those of Prevost,
Dumas, and others, who found in the first days
after copulation ova in the Fallopian tubes of
a size considerably less than the vesicles of the
ovary from which they had proceeded, proved
satisfactorily that the ovarian vesicles and ova
are not identical. Various conjectures were in
the meantime offered by different authors as to
the source of the ovum ; some holding it to be
formed by a process of secretion, others by
an organic union of the male semen with the
contents of the Graafian vesicle, and so forth ;
but no one ever observed the ovum itself of
mammiferous animals within the ovary, until
Baer made this important discovery in 1827,
by the examination with the microscope of the
fluid contents of the Graafian vesicle.'*

Baer found that, in the centre of a granular
layer, placed generally towards the most promi-
nent part of the vesicle, to which he gives the
name of proligerous disc or layer, there is fixed
a very minute spheroid body, seldom above
5^jth part of an inch in diameter. The appear-
ance of this body he found to be constant, and
on examining it with attention in the vesicles
of the ovaries, and after their rupture in the
Fallopian tubes, he traced the changes it un-
derwent in the first days after copulation, and
established satisfactorily the identity of this
body with the ova found by previous observers
in the Fallopian tubes and cornua of the uterus;
thus proving by actual observation what had
before been held only from analogy, that in the
mammiferous or truly viviparous, as well as iu
the oviparous animal, the foetus derives its origin
from an ovum already formed in the ovary
before fecundation .f

* Epistola de Ovi Mammalium et Hominis
Genesi. Lipsiae, 1827.

t We have no hesitation in giving the sole and
undivided merit of this discovery to the indefatiga-
ble and talented Baer, whose observations have con-
tributed, perhaps more than any other single indivi-
dual of the present time, to extend our knowledge
of the early formation of the foetus. We ought not,
however, to omit to mention that Messrs. Prevost
and Dumas conceived that in two instances they
had perceived ova in, the ovarian vesicles of quad-

GENERATION.

449

Some time after sexual union the fluid con-
tained in the vesicles which are about to burst,
previously transparent and nearly colourless,
now becomes more viscid and tenacious, some-
what turbid and of a reddish colour ; and in
some animals it is possible in such ripe vesicles
to perceive, with the unassisted eye in a favour-
able light, a whitish opaque spot on the most
prominent part, indicating the layer of granules
or proligerous disc, in the centre of which the
ovum is situated. After a certain time a small
opening is formed at the most prominent part
of the coverings of the vesicle, the vesicle bursts,
and its contents escape through the opening ;
they are received in the infundibulum, which is
now applied firmly against the ovary ; and the
ovum entering the Fallopian tube is conveyed
along it, probably by its slow and gradual ver-
micular contractions, until it at last arrives in
the uterus.

With regard to the time at which the opening
of the ovarian vesicles takes place, there are
considerable varieties in the same and in diffe-
rent animals. In the sheep, the vesicle has
been found burst so early as at two hours after
coition. In the dog, Haller found the vesicles
burst before the sixth day ; in one instance the
day after coition ; but Prevost and Dumas, not
until the seventh or eighth. In the rabbit,
Cruikshank observed vesicles burst two hours
after coition, while Haighton considers forty-
eight hours as the usual time at which the rup-
ture happens in this animal. M. Coste has
observed it most frequently between the second
and third day in the rabbit.

After the bursting of the Graafian vesicles,
there occur in them and in the neighbouring
part of the ovary some important changes of
structure, which claim our attention in this
place as intimately connected with that part of
the process of conception which is now under
consideration.

If the Graafian vesicle which is enlarged
from venereal excitement and is ready to burst,
be examined with care, it will be seen that at
the most prominent part of its coats the blood-
vessels converge towards the point at which

rupeds, (Annal. d. Scien. Nat. torn. iii. p. 135,)
but without any certainty or exact knowledge as to
their nature. M. Coste, with a spirit of appropria-
tion too common, we regret to say, among his coun-
trymen, has taken advantage of some speculative
views and strained analogies brought forward by
Baer concerning the bodies which he discovered, in
which he compared them (erroneously as we think)
to the germinal part only of the ovum, rather than
to the whole ovum of the oviparous animal, to take
from the merits of Baer in their discovery ; but we
feel assured that every unprejudiced inquirer who
reads with attention Baer's admirable " Epistola
de Ovi Mammalium et Hominis Genesi," in which
his discovery was first announced in 1827, and
compares it with other works on the subject,
will be convinced that Baer has no sharer in the
discovery, and fully understood the nature of the
ovarian ovum of viviparous animals ; although
it tmay be the case that subsequent investigations
have added considerably to the knowledge of the
relations of these ova. We shall return to a more
minute detail of this body in considering the process
of formation of the ovum in the present article and
under the article OVUM.

the rupture afterwards takes place, and this
point is itself comparatively destitute of blood-
vessels.*

At the time of the formation of the opening
into the vesicle, from the division of some of
the bloodvessels, a small quantity of blood is
generally mixed with the fluid contents of the
vesicle ; and after the vesicle has been emptied
of these fluid contents, their place is generally
supplied by a greater or less quantity of coagu-
lated blood, probably poured out by the same
ruptured vessels.

The membranes of the vesicle at this time
have become thicker than before : the inner
one in particular appears more vascular and
uneven, perhaps in part from its being puckered
up on the vesicle becoming flaccid and com-
paratively empty. The wrinkled appearance
on the inner surface of the vesicle increases,
and there grows gradually out from it a new
substance which comes to occupy the whole
cavity of the vesicle ; and in many instances,
as this new substance is formed in greater
quantity than can be contained within the limits
of the vesicle, it protrudes some way out at
the opening of the vesicle, forming a dark red
prominence like a nipple, which rises above
the neighbouring surface of the ovary. This
substance, at the time of its first formation, is
of a pink or reddish colour, but as it becomes
gradually less filled with blood it acquires a
yellowish hue, which is more or less apparent
in different animals. In the human species it
is of a bright yellow colour, whence the name
of corpus luteum applied to this new produc-
tion of the ovarian vesicles.

The substance of the corpus luteum has a
lobular structure ; the lobules radiating in a
somewhat irregular manner from the centre to
the circumference. The central part of the
corpus luteum frequently remains hollow for
some time after its production, opening ex-
teriorly by a narrow passage from the place
where the rupture of the vesicle originally took
place ; at other times this passage is closed
more early, and there remains nothing but an
indication of its place in a depression in the
centre of the most projecting part of the corpus
luteum. The lobules of the corpus luteum,
examined with the microscope, exhibit merely
a granular structure, and are not formed of
acini, as some have described them, so that
there is no reason to consider these bodies as
of a glandular nature.

The size which corpora lutea attain when
fully developed varies much in the same and
in different animals. In the human female
they become as large as a common hazel-nut ; in
the cow they are sometimes as large as a ches-

* The ovarian capsules of the bird, which are
obviously the analogous parts of the ovarian
vesicles of quadrupeds, present on their most pro-
minent part a remarkable band, extending for
nearly one-third of the periphery : towards the
margins of this band the small bloodvessels all
converge, but they do not pass upon the band
itself, so that it is left free from bloodvessels. It
is in this non-vascular or less vascular part of the
capsule that the rupture takes place when the yolk
escapes.

450

GENERATION.

nut ; and in the sow or ewe they are somewhat
larger than full-grown peas.

The corpus luteum may, by dissection, be
easily separated from the surrounding parts and
turned out of the ovary ; and when this is
done, the external membrane of the original
vesicle remains lining the cavity left in the
ovary. From this it would appear that the
corpus luteum is most intimately connected
with the inner membrane of the vesicle ; and,
in fact, Baer* observed that, before the rupture
of the vesicle in the dog, the inner membrane
had become thickened, rugous, and of a villous
structure, as if the corpus luteum grew from
that internal membrane itself. This observa-
tion also makes it probable that the growth of
the corpus luteum may contribute to cause the
rupture of the vesicle.

The corpus luteum at first increases gradu-
ally in size, remains for a time stationary, and
then decreases till it either wholly disappears
or leaves only a small mark or cicatrix to indi-
cate its place. The time at which it attains
its full size seems to vary considerably. In
the sheep two or three days are sufficient for
the formation of the corpus luteum, and its
cavity becomes obliterated within a fortnight
after copulation. Haller found corpora lutea
in the dog on the sixth day; Cruikshank
observed the corpora lutea to go on progres-
sively increasing till the ninth day in the
rabbit; and it is probable that in the human
species the corpus luteum is not fully developed
till after the second month of pregnancy.

After the corpus luteum has attained its full
magnitude, its colour becomes paler and of a
clearer yellow; its size then gradually dimi-
nishes, its tissue becomes more compact, its
cavity is obliterated, and it is converted into a
body nearly solid. It generally retains, during
utero-gestation, a considerable size, and this
remark applies especially to the human species,
in which it diminishes much more rapidly in
size after than before the birth of the child. In
some animals it at last wholly disappears ; in
others, among which is the human species, it
always leaves some mark.

In what has now been said regarding the
corpus lureum, that body has been described
as it is formed in the place of a vesicle which
has been burst after fruitful sexual union ; but
we may remark that the same series of changes
always follows the rupture of an ovarian
vesicle from whatever cause that may have
proceeded. It is now well known that in
some animals the rupture of ovarian vesicles
and subsequent changes take place without
sexual union merely from the state of heat or
venereal excitement of any kind, while in
others these phenomena are never observed
but as accompaniments of conception. The
sow and mare belong to the first of these classes
of animals. The rabbit, bitch, ewe, and cow
may be mentioned as examples of the second, as
also is generally the case in the human female ;
but in woman, as in some other females, various
circumstances induce us to believe that the

* See Epistola, &c.

rupture of ovarian vesicles and the formation
of corpora lutea in their place occasionally
happen without sexual union from all those
causes which excite greatly the sexual organs ;
and we are not, therefore, inclined to admit
the presence of a corpus luteum, . taken alone,
as a certain sign of sexual union having oc-
curred ; though conjoined with other signs, the
presence of one or more corpora lutea or the
appearance of ruptured vesicles must be re-
garded as good presumptive evidence.

In some of those animals in which vesicles
frequently burst without sexual union, there
are occasionally very many corpora lutea in
the ovary, so as to alter completely its form, and
disguise its natural structure, as may frequently
be seen in the sow. In those animals again
in which sexual union alone brings about the
rupture, we at once distinguish the ovary of
the unimpregnated animal from that of the one
that has had connexion with the male, and we
very generally observe an exact correspondence
in the number of corpora lutea and the ova or
foetuses contained in the uterus;* and the
same correspondence is very frequently found
after conception, even in those animals in which
corpora lutea are formed without sexual union.

While the corpus luteum, then, is always to
be found in the ovary of a pregnant quadruped,
the formation of this body is to be regarded as
the uniform consequence of the rupture of the
ovarian vesicles, whether thai rupture shall
have been occasioned merely by excitement of
the organs, or by productive or unproductive
sexual union ; but it is only when conception
and pregnancy occur that the corpus luteum
attains its full size, and runs through the whole
of that series of changes which we have described
as peculiar to that body.

We ought not to omit here the mention of a
totally different view which has been taken of
the corpora lutea, that, viz. of Buffon and Val-
lisneri,f supported more recently by Sir E.
Home,J according to which it is held that the
corpora lutea exist before the rupture of the
vesicles, and are the matrix in which the vesicles
and ova are formed.

Two circumstances principally have been
brought forward in favour of this hypothesis : —
1st, that corpora lutea occur in the virgin state;
and 2d, that they frequently contain vesicles.
Now the existence of corpora lutea, we have
already stated, in the sow (observed by Sir E.
Home;, and even, we are inclined to hold, in
the human female, is not necessarily a proof
of sexual union having previously occurred,
since the rupture of the vesicles may have

* It may be mentioned that more than one ovum
have sometimes been found in the same Graafiaii
vesicle, in which case it will readily be understood
there might be only one corpus luteum in the ovary
and two ova in the uterus, but this is rare. The
author has verified the above correspondence in
many hundred pregnant ewes, in a considerable
number of cows, rabbits, some cats, and other
animals.

t Vallisneri, Hist, of the Generation of Man and
Animals (Ital.).

$ Phil. Trans., vol. cviii. p. 256, and vol. cix.
p. 59.

GENERATION.

451

followed simple excitement of the sexual
organs, and might therefore take place either
with or without the male ; and in the second
place, the occurrence of cavities and vesicular
membranes within the corpora lutea is by no
means a proof that these cavities are new or
forming ovarian vesicles ; on the contrary, there
is every reason to regard them as unnatural or
the product of disease. But though lately
revived upon the above-mentioned grounds, it
is long since this hypothesis received the most
satisfactory refutation, both from the observa-
tions of De Graaf and of Haller. Haller in
particular traced in the most accurate manner
all the steps of the development of the corpus
luteum, from the first rupture of the vesicle
till its completion : he employed the animals
least liable to lead to fallacy in such observa-
tions ; those, viz. in which rupture of the
vesicles and formation of corpora lutea is
usually produced only by sexual union ; and
he always remarked in them an exact corres-
pondence in the number of foetuses in the
gravid uterus with the number of corpora lutea
in the ovaries, while at the same time he found
the first appearance of these bodies to take
place at a fixed period after sexual union, and
their size and structure always to bear an exact
relation to the period of utero-gestation at
which they were observed.*

The uses of the corpora lutea are entirely
unknown. The fact that these bodies become
larger and remain proportionately of a larger
size during pregnancy than when produced in
other circumstances (as without sexual union,
or after unproductive copulation, or when the
product is blighted at an early period of utero-
gestation,) would seem to indicate some con-
nexion between the corpora lutea and the
development of the foetus in utero. By those
who have regarded the corpora lutea as of a
glandular nature, they have been supposed to
secrete fluids which assist in the nourishment
of the foetus. We have already stated the
reasons for considering such hypotheses as
groundless. (See OVARY.)

Descent of the ovum. Its structure and
changes during its passage. — The attention of
accoucheurs in all ages and countries has
naturally been directed to the study of the
structure of the human ovum and foetus in the
more advanced stages of utero-gestation, and
a great body of facts has been collected from
the examination of aborted products or the
gravid uterus of women dying during preg-
nancy, from which scientific men have acquired
an accurate knowledge of the structure of the
human foetus and its covering in the ovum
during the greater part, and especially in the
more advanced period of utero-gestation ; but
very little is known of the nature of the egg
in the first stages or immediately after concep-

* The corpus luteum is developed then and be-
comes perceptible after the bursting of one of the
vesicles •, but let us not here lose sight of the fact
before announced that the first commencement of
its formation dates from a short while before the
rupture, as indicated by a thickening of the inner
membrane of the vesicle.

tion has occurred. We hare, in feet, no direct
observations which inform us of what happens
to the human ovum immediately after its escape
from the ovary, and, indeed, for some little
time after its arrival in the uterus, when the
parts of the foetus have already begun to be
formed in it. This subject has, however, been
investigated with considerable success in several
mammiferous animals ; and although there
remain several points which still require eluci-
dation, yet, from the analogy which is known to
exist in the structure of the ovum and foetus
of the human species and those of quadrupeds
and birds, we are enabled to bring together the
detached observations which chance has thrown
in our way, and thus to give a connected
account of the generative process in man, im-
perfectly as that process has as yet been
observed.

Our design at present is to follow the ovum
only as far as into the uterus, or until the com-
mencement of the formation of the foetus in it.
We believe we shall place this part of our sub-
ject in the clearest point of view, by prefixing
to our remarks regarding the ovum of man
and quadrupeds a short sketch of what happens
to the egg of the common fowl after its dis-
charge from the ovary.

The substance of the yolk enclosed in its
membrane, together with the germinal portion
in which after incubation the rudiments of the
new animal begin to be formed, constitutes the
essential parts of the bird's egg as it exists in
the ovary. The ovarian egg, when it has left
the place of its formation and passed into the
oviduct, receives the addition of various other
parts, viz. the albumen, chalazae, shell and
its lining membrane, as it gradually descends
through different portions of the oviduct, each
of which is destined to secrete one of these
newly added parts. These parts may, however,
be considered as accessory to the more essential
constituents of the egg, which we are inclined
to regard as the germinal spot or cicatricula,
the granular and oleaginous fluid of the yolk,
and the dense transparent membrane with
which they are enveloped. To the unim-
pregnated egg of the ovary we shall give the
name of ovulum, and henceforward in this
paper apply the name of ovum to the perfected
egg, that is, the ovulum to which the acces-
sory coverings have been added, and which
has received! the influence of the male. The
ovarium of the common fowl in the breeding
season, or when it is laying eggs, has the form
of a bunch of clustering ovula, which are
contained in capsules, the more advanced of
which hang down from the rest of the ovary
by the elongated pedicles of the containing
capsules ; while the smaller ovula of various
sizes, composing the body of the ovary, cluster
more closely together. The fully developed
ovula only have the deep yellow colour pecu-
liar to the yolk ; as the smaller ones are less
advanced their colour is paler, and the smallest
are nearly colourless and transparent from
the absence in them of the oleaginous and
granular matter peculiar to the riper yolks.

The little white spot or granular layer which

4<>2

GENERATION.

constitutes the cicatricula or germinal disc is
easily seen in the larger ovula, occupying
almost always the same position on the surface
of the yolk, somewhere near the pedicle of
the ovarian capsule. When the cicatricula is
examined carefully in the ovulum, a small
dark round spot is perceived in its centre, the
relations of which to the first production of the
foetus are very important. This little dark
spot was discovered by Purkinje to contain im-
planted in the centre of the cicatricula a minute
transparent vesicle filled with fluid. He farther
shewed that during the passage of the ovulum
from the capsule of the ovary into the infun-
dibulum of the oviduct, this little vesicle dis-
appears, being probably burst, and leaves in
its place a thin and tender transparent mem-
brane. The vesicle of Purkinje, as it is called
from its discoverer, occupies then the centre of
the germinal spot, and it is in the transparent
membrane left in its place when the vesicle is
dispelled that the first rudiments of the foetus
afterwards make their appearance. Hence the
vesicle has also received the name of germinal
vesicle, a most appropriate term, since it may
be regarded as the more immediate seat of the
germ or germinating faculty of the egg.

The Purkinjean or germinal vesicle exists in
the smallest as well as in the more advanced
ovula of the fowl's ovary, and it is proportion-
ally much larger in small than in large ovula.
In the very small ovula it is not, as in the riper
ones, situated on the surface of the yolk, but
towards the centre of that body; and as the ovu-
lum advances to perfection, the germinal vesicle
gradually approaches more near the surface,
and becomes more prominent on the surface of
the cicatricula. In ovula less than two lines
in diameter the vesicle is usually unconnected
with the germinal layer or cicatricula, but in
those of four lines in diameter it is already
placed in the middle of the germinal spot.

In all oviparous animals a vesicle, simi-
lar to that now described in the common fowl,
occupies the central part of the germinal layer
so long as the ovulum remains in the ovary,
and undergoes the same rupture and other
changes at the time of the discharge of the
ovulum from the ovary.*

In turning now to mammiferous or vivipa-
rous animals, it may be remarked in the first
place, that although the extremely minute size
of the body discovered by Baer to be constantly
present in the ovarian vesicle prevents us from
observing it with ease, and establishing with
certainty its analogy to the yolk and its accom-
panying parts in the egg of the fowl before deve-
lopment begins ; yet after the commencement

* Purkinje's description of this vesicle was first
given in his excellent " Symbolae ad ovi ovium
historiam ante incubationem, Vratisl. 1825," and
second edition at Leipzig, in 1830. Baer contri-
buted in his " Epistola" many important facts
concerning its existence and changes in other ovi-
parous animals. Coste, Valentin, and Wagner
have since added several observations. We may
state here that the bursting of the vesicle does not
occur in all oviparous animals exactly at the time
of the escape of the ovulum from the ovary, but
nearly about the same time.

of foetal formation, the early changes which this
body undergoes prove its correspondence with
the ovum of birds in a most satisfactory manner.
We have already, however, stated the reasons
for regarding the vesicle of Baer as the ovulum
of mammalia, and need not now recapitulate
them. We shall only remark that although
the vesicle of Baer and ovulum of birds differ
widely in size, that vesicle appears to contain
the same essential parts of the egg belonging
to birds and other oviparous animals, viz. a
fluid granular mass or yolk enclosed by an in-
vesting membrane, and furnished also with a
more compact granular layer situated on the
surface of the yolk, but also enveloped by its
membrane, in which the rudiments of the
foetus first appear, and which is, therefore, the
germinal layer of the mammiferous ovum.

The membranes of the ovarian vesicle in
mammalia and the capsules of the ovary, in
the fowl are corresponding parts, and the prin-
cipal difference between the ovarian cavities
containing ovula in oviparous animals, and
those of viviparous animals, consists in this,
that in the latter the ovulum (the vesicle of
Baer) is placed in the granular proligerous disc,
and has all the fluid of the vesicle interposed
between it and the coats of this cavity.

At the time when Baer first discovered the
ovulum of mammalia, there was still wanting,
in order to complete the proof of its analogy with
the ovulum of birds, the observation of the ger-
minal vesicle (vesicle of Purkinje) within it.
This additional proof has been supplied within
the last few years by the researches of T. W.
Jones, Coste, Purkinje, Valentin, and Wag-
ner, which we have ourselves confirmed.

The germinal vesicle of the very small ovu-
lum of quadrupeds is of course a most minute
object, and in fact it can only be seen with a
good microscope ; but in favourable circum-
stances it is nevertheless quite distinct, and
the investigations above referred to, conjoined
with analogical evidence, make it highly pro-
bable that the little vesicle found within the
ovulum of viviparous animals occupies the
place in which the foetus first makes its ap-
pearance, and that at the time of the passage
of the ovulum from the ovary to the Fallopian
tube this little vesicle is burst, and undergoes
analogous changes to those which have been
noticed in the fowl.*

In birds the shell with its lining membrane
forms the external covering of the egg ; and in
all oviparous animals a similar external enve-
lope (besides the membrane enclosing the yolk)
is to be found, though varying greatly in thick-
ness, consistence, and structure in different
animals. The ovum of mammalia at the time

* In his " Epistola/' published in 1827, Baer
compared the vesicle he had discovered within the
Graafian vesicles of the ovary to the vesicle which
Purkinje had in 1825 discovered in the cicatricula
of the fowl's yolk : erroneously as we think ; for
the facts mentioned above are sufficient to disprove
any such analogy. For the sake of clearness we
here subjoin a tabular view of the parts which
correspond with one another in the bird and quuil-
ruped.

GENERATION.

453

when it arrives in the uterus has also a similar
external envelope, which has received in man
and most animals the general appellation of
chorion. Baer is of opinion that the chorion
exists ready formed in the ovulum of the
ovary ; but his observations appear to us as
yet insufficient to prove this point, and we feel
inclined rather to adopt the view of Valentin,
who holds that it is probable that the chorion
is added to the ovulum after it has left the
Graafian vesicle, that is, during its passage
from the ovary to the uterus, somewhat in the
same manner as the albumen or shell is added
to the egg of the common fowl in its passage
through the oviduct. The analogy of all ovi-
parous animals is at least strongly in favour of
such a view of the mode of the production of
the chorion or external envelope ; while on the
other hand we ought not to lose sight of the
fact that though the external envelope or cho-
rion occupies the same position as the external
covering of the eggs of oviparous animals, its
structure and functions are very different, for
almost in every quadruped the chorion serves
important purposes in establishing that more
intimate union peculiar to viviparous animals,
which is formed between the ovum and uterus
in the placenta or analogous structure.

It is only in the dog and rabbit that the ova
have hitherto been traced by actual observation
in the whole course of their progress through the
Fallopian tubes from the ovary to the uterus.
These observations we owe chiefly to the care-
ful researches of Cruikshank, Prevost and
Dumas, Baer, and Coste. In regard to other
animals we have only a few detached observa-
tions in some of them, and in the human
species the ova have never been observed in the
Fallopian tubes, nor indeed for some time
after they must have entered the uterus. We
do not therefore know, with any degree of cer-
tainty, at what distance of time after sexual
union the ovum passes into the uterus of the
human female. Great difficulties attend the
elucidation of this point. In the first place,
we are opposed by the impossibility, in the
greater number of cases in which we may hap-
pen to obtain a pregnant uterus for investiga-
tion, of knowing accurately the age of the
product or the time at which impregnation has
occurred; and in the second place, we are
here deprived of the assistance derived in

In the Quadruped.

1. The ovary contains

2. Graafian vesicles
which are filled with
fluid, granules, and
the proligerous disc,
in the centre of which
is placed

3. The ovulum or vesi-
cle of Baer, consisting
of

4. A yolk, on the sur-
face of which is

5. A germinal membrane,
in the middle of which
is placed

6. The germinal vesicle
or vesicle of Pnrkinje.

In the Bird.

1. The ovary contains

2. Capsules entirely filled
with ovula, there being
no intervening fluid or
proligerous disc.

3. The ovula or yolks,
consisting of

4. A yolk.

5. A germinal membrane
or cicatricula with the

6. Vesicle of Purkinje in
its centre.

many other parts of our subject from analogical
evidence by the wide discrepancies we find
among animals in respect to the period of the
arrival of the ova in the uterus ; for there does
not appear to be any exact correspondence yet
shewn between the time at which this happens
and the length of duration of utero-gestation.
It may be well, however, to endeavour to
form an approximative opinion. In the rabbit,
although ova are known frequently to be dis-
charged from the Graafian vesicles on the se-
cond day after sexual union, they are in general
not detected in the uterus before the third or
fourth day, and frequently not before the fifth
or sixth, at which time they appear as vesicles
a little more than a line in diameter, lying un-
attached in the upper part of the cornua of the
uterus.*

In the dog ova have been observed in the
Fallopian tubes on the eighth day, but they
have not been found in the uterus before the
twelfth day. In the cat we have found ova of
the size of peas beginning to be attached to
the uterus at the twelfth day, and in both the
cat and dog we think it probable from the size
of the ova that they had already been in the
uterus for at least one day, so that the tenth
or eleventh day may be regarded as the time
when ova generally appear in the uterus of
these animals.

Haller and Kuhlemannf never found an ovum
in the uterus of the sheep till the seventeenth
day after copulation, and our own observations
on both the sheep and sow agree precisely
with theirs. Hausmann never found the ova
in the uterus of the sow before the period of
four weeks after conception, and those of the
bitch before three weeks ; but here we must
caution the reader against the error of sup-
posing that in the sheep and some other
animals, because the ova have not been ob-
served in the uterus, they do not actually
exist there previous to a certain date ; for the
large size of the ovum and its membranes, as
well as the state of the foetus, which though
small is already somewhat developed, entitle
us to conclude that the ovum of the sheep
must have been some time in the uterus. The
recent interesting observations by M. Coste
have thrown great light upon this subject, he
having detected the ova of the sheep so early
as five days after conception. In the cow also,
in which the period of gestation is nearly twice
the length of that in the sheep, the ovum
seems to arrive almost as early in the uterus,
if we may judge from the state of advancement
of the foetus at an early period.];

* M. Coste has shewn that there is considerable
variety in respect to the time at which the ova
descend in the rabbit, and thus very reasonably
accounts for the difference one generally finds in
the state of advancement of the ova in the preg-
nant uterus.

t Vide Kuhlemann's Observ. quaed. circa nego-
tium generations in ovibus fact. Gott. 1753.

J Immediately after the arrival of the mammi-
ferous ovum in the uterus it increases in bulk with
amazing rapidity, and its membranes being thus
suddenly dilated become in consequence very weak
and thin ; so tender indeed are they, that if they

454

GENERATION.

With regard now to the time at which the
ovum first enters the uterus in the human fe-
male, let us examine the facts which are
before us. The greater number of observations
of this kind are made on aborted products;
many of these are malformed or diseased, in
consequence of which very probably they have
been thrown off by abortion ; others are injured
by the violence of the action which causes the
uterus to be emptied of its contents. Our
knowledge of the time of conception is generally
founded upon the cessation of the menstrual
flow on the first occasion when it ought to
have recurred after conception has taken place,
and conception may in the greater number of
instances have taken place at any period of the
interval. In a very few cases only have we
any means of determining the time of concep-
tion, and in still fewer instances has there been
an opportunity of examining the uterus in situ
at an early period after conception when the
period of sexual intercourse was known. In
by far the greater number of instances, there-
fore, there may be an error in the calculation of
ten days or a fortnight.

It is by no means rare to see specimens of
the human ovum or foetus in anatomical col-
lections marked as being a fortnight or three or
four weeks old ; but it is now generally ac-
knowledged that the greater number of these
are incorrectly marked. We have seen, however,
more than one such ovum, which, both from
the history of the cases and from the structure
and size of the parts of the ovum and fcetus,
we should be inclined to consider as dating
between three and four weeks after concep-
tion.*

once burst it is impossible to recognize any parts
of the ovum, frequently in instances where we
are certain it has existed. Baer in a second
epistle (published in Breschet's Repertoire, vol.
viii. p. 175) mentions these difficulties of mani-
pulation in extracting the ova from the gravid
uterus of the dog during the early periods, and
advises that, on account of the violent contrac-
tions which are apt to ensue in the uterus from
its exposure to the air, the animals should not
be opened, but left perfectly quiet for eight or
twelve hours or more after death. We have fre-
quently pursued this plan advantageously in the
rabbit and cat ; and have even found it neces-
sary to harden the ovum and uterus in alcohol
before being able to extract the former. The same
circumstances may account for our never finding the
ovum of the sheep before the seventeenth day, for
those we examined were all killed at the market,
and consequently opened immediately after death
while the contractility still remained in the uterus.
At earlier periods we have in fact frequently found
shreds of membrane, and some of the earliest ova
which we found were partly destroyed ; but in a
very short time afterwards the membranes of the
egg and parts of the fo?,tus acquire sufficient con-
sistence to resist the pressure.

* So common in museums are the specimens of
blighted ova which are considered as examples of
very early date, that the author confines himself
here to the mention of those which he has himself
seen, making this general remark, that in all those
specimens below the alleged age of six or seven
weeks, in which the fo?tus and membranes, parti-
cularly the amnion, are disproportionate in size,
that is, the first very small and the latter large,

Tbere are some who describe the human
foetus at less than a fortnight old, and even as
early as the eighth day, as in the well-known
and often-quoted example described by Sir E.
Home. But there is some reason to think that
Sir E. Home was mistaken in the case alluded
to. Either, supposing that conception had
occurred eight days before death, the body
in question was not the foetus, or if it was the
foetus, it must have been considerably older
than he supposed.

The earliest example of the human ovum
with which we are acquainted is that mentioned
by M. Velpeau in his work sur I'Embryologie
Hum aine ; which, if he was not deceived by
the person who gave it to him, he had the best
reason to believe was discharged on the four-
teenth day after sexual intercourse.

This ovum, the description and drawings of
which are very meagre, is described as about
the size of a pea ; the fcetus was already some-
what formed, though very small ; and all points
of structure in the foetus and ovum appear to
us (so far as we can judge from the description)
to correspond with one another, and to shew
that the product was quite natural. This ovum
from its size and from the state of advancement
of the fcetus must have been in the uterus at
least two or three days.

We possess also the recent record of two
valuable observations made on the structure of
the gravid uterus of females dying suddenly
eight days after sexual intercourse ; the one by
Weber, the other by Professor Baer. No ovum
was detected in either of these instances either
in the uterus or tubes. We feel inclined to
place much reliance on these two observations
as being made by persons well acquainted with
the various circumstances necessary to be at-
tended to in such a delicate investigation, and
with all the advantages of recent knowledge,
and though they afford negative evidence only,
yet we are disposed to found upon them as
proofs that at the eighth day the ovum has not
descended into the uterus.

On comparing the degree of advancement
of the foetus in the ovum described by Velpeau
and in others with that of the fcetus in the dog,
cat, and sheep, at known periods, we would
hazard the opinion that the human ovum arrives
in the uterus on the eleventh or twelfth day after
conception. Valentin thinks the twelfth or four-
teenth day, but we are inclined to believe that
it cannot be much later than in the dog.

Change of the uterus after conception. —
Before the arrival of the ovum in the uterus,
a change has already taken place in the interior
of that organ preparatory to the reception of
the foetus. An exudation of a substance having
many of the characters of organizable lymph

then the product is unnatural, and we ought to
judge of its age more by the extent of the mem-
branes than by the size of the foetus. We feel
inclined to believe that some of the views adopted
by Dr. Pockels of Brunswick, in his interesting
paper on the early structure of the human ovum
and fcetus (to the consideration of which we shall
return in the. article OVUM), are founded upon the
examination of unnatural specimens.

GENERATION.

455

furnishes a soft flaky lining to the cavity of the
uterus, and serves to form a covering of the
ovum when it afterwards descends into the
uterus. This newly formed substance is re-
flected over the ovum so as to give it a double
covering, the two layers of which constitute the
two folds of the decidual membrane. The
decidua is filled with bloodvessels formed by
a process of organization similar to that which
occurs in inflammatory adhesion by coagu-
lable lymph. These bloodvessels are conti-
nuous with those of the uterus, and as the
ovum advances in the progress of develop-
ment, they are much dilated in some parts
so as to form sinuses, which are ultimately
intermingled, though by no means continuous
with the bloodvessels which pass out of the
umbilicus of the foetus. The placenta or or-
ganic connection between the female parent
and child, by means of which the respiration
and partly also the nutrition of the latter is car-
ried on, is in great part formed in the decidua
with which the flocculent chorion is closely in-
corporated ; but the description of these parts
belongs to another place.

In a former part of this essay it was remarked
that rupture of the Graafian vesicles and dis-
charge of the ovula from them, as well as the
formation of corpora lutea, may take place in
some animals without the concurrence of the
male : there is reason to believe that in some
cases the decidua may in part be formed with-
out conception having occurred, as in the cases
of moles, &c. When these changes have oc-
curred without conception in Mammalia, it is
quite possible that the ova may have been car-
ried down the Fallopian tubes ; but as they are
unfecundated, they undergo no enlargement,
and consequently we do not know what be-
comes of them.

In many oviparous animals the same is the
case, that is, ova are frequently discharged from
the ovaries without the concurrence of the male,
as happens in the common fowl and other
birds, in some reptiles and fishes. But even
in those animals in which barren ova are thus
excreted by the female, union with the male
renders the exclusion of the egg more easy and
regular, and it is consequently not uncommon
for female oviparous animals which are removed
from the males to die at the season of breeding,
when the ova are formed in their ovaries or de-
scend from that organ into the oviduct. This
is beautifully described by Harvey as befalling
his lady's parrot, which he had always taken
for a male bird, but which, after being much
fondled, died of " a corrupted egg impacted
in the oviduct;" and also in a cassowary kept
in the royal gardens, which, after being some
time there, was excited by being placed in the
vicinity of a male and female ostrich, and
having laid one egg, died of a second being re-
tained in the oviduct.

In the common fowl indeed, when highly
fed, so great is the productive energy both of
the ovary and oviduct that they will continue
to lay eggs during a whole season without the
assistance of the male ; but this is well known
to be often very pernicious to the bird, as many

of those kept without the cock die ; and it
not unfrequently happens that eggs, or bodies
like eggs, are laid by them containing no yolk,
but consisting only of the albumen, membrane,
and shell, which are the product of secretion
from the oviduct, and that in others large
masses of imperfectly formed eggs accumulated
together are lodged in the genital passages.

These facts exhibit in a strong point of view
the powerful productive energies of the female
generative organs independently of the concur-
rence of the male; for it is sufficiently obvious
from them that the greater part of the substance
of the egg is due to the female, and that ova, to
all appearance perfect,* though unfit for repro-
duction, may be brought forth by the female
wholly independent of the male. Some authors
also adduce as examples of this independent
productive energy of the female, the occurrence
of bones, hair, teeth, &c., in close cysts of the
ovaries of women and female quadrupeds, but
this leads us too far into the regions of vague
supposition.

Irregularities in the descent of the ovum. —
This appears to be the proper place at which
to make mention of a few irregularities that
have been observed in the descent of the ovum,
which are attended with important modifica-
tions of the generative process.

In the bird it not unfrequently happens
that the yolk or ovulum which has been
discharged from its burst capsule in the ovary,
instead of descending through the oviduct, and
having added to it the external accessory parts,
escapes from the infundibulum or oviduct into
the cavity of the peritoneum. This irregu-
larity occurs most frequently among those
fowls which are laying eggs without the
male, and in which it may be supposed the
usual and regular performance of the appro-
priate motions is not ensured by venereal ex-
citement. These yolks sometimes remain for
some time in the cavity of the abdomen, and are
afterwards gradually removed by absorption :
in other instances they cause death. Upon
every occasion when the ovulum is discharged
from an ovarian capsule, the oviduct is excited
to the secretion of albumen, membrane, and
shell, and hence the ova subventanea, which
consist only of these accessory parts without the
yolk.

In other instances, either from a mechanical
obstruction to the passage of the egg, or from a
deficiency in the muscular power of the oviduct,
the product becomes impacted in the passage,
and there are formed large masses of accumu-
lated ova subventanea, with or without yolks in
some part of the oviduct or in its vicinity.

In some instances, extremely rarely met with,
it is stated by Geoffrey St. Hilaire (Annal.
du Museum d'Hist. Naturelle) that ova de-
tained in the oviduct have become slightly de-
veloped, and the author owes to the kind-
ness of his friend, Mr. Daniel Ellis, the his-
tory of several examples of the same ano-

* We shall have occasion to consider elsewhere
more minutely the difference between the lecun-
dated and the unfecundated ovum.

456

GENERATION.

maly ; but it may be stated as a general rule
that this does not occur in oviparous animals,
and more especially in birds, in which a con-
tinued supply of fresh air around the shell is
necessary to promote incubation, and we do
not know of any examples of truly oviparous
animals in which the foetus has been formed in
an egg accidentally retained within the body of
the parent. In none of those which we have
observed was there any appearance of foetal
formation.

It is possible that some irregularities in the
position of the ovum of mammalia during ges-
tation may receive an explanation from mecha-
nical disturbances similar to those we have now
mentioned in birds ; for supposing that in a
viviparous animal the ovum does not gain the
uterus or usual place of its abode during gesta-
tion, development of the foetus still takes place.
In those instances in which a foetus is formed
in the region of the ovary, or in what are termed
ovarian conceptions, for example, it is not pro-
bable that the ovum is ever developed in the
ovary itself without the bursting of the Graafian
vesicle : it may be fixed close to the ovary, but
it is always independent of that body. After
the Graafian vesicle has burst, the ovum may
be supposed either not to have been received
in the Fallopian tube, or, after having entered
that passage, to have been expelled from it by
an inverted action of its muscular fibres or other
causes. Fecundated by the contact of some of
the seminal fluid which has reached so far
into the Fallopian tube, the ovum remains in
the neighbourhood of the ovary, has a cyst
formed round it, and becomes organically
united to the ovary or parts in its vicinity by
structures similar to those which unite the ovum
to the inner surface of the gravid uterus ; for
the bloodvessels of the mother which run into
the cyst enlarge and form a placenta by their
union and intermixture with those of the foetus,
and thus for a considerable time (amounting
sometimes to four or five months) this ovarian
or extra-uterine gestation is carried on.

In other instances of misplaced gestation, the
ovum seems to have been arrested in its course
when more or less advanced in the Fallopian
tube ; but here also the parts are susceptible of
all those remarkable changes and growth which
favour the development of the foetus in the
ovum. We mention these instances of extra-
uterine gestation with the view of directing the
reader's attention to an inference which may be
drawn from them, viz. that all those changes
of growth upon which the development of the
ovum in viviparous animals depends may be
regarded rather as belonging to the ovum itself
than as resident in the uterus alone. It is
worthy of remark, however, that in ovarian and
tubular conceptions the decidua is formed
within the uterus, nearly in the same manner
as if the ovum had descended in the natural
way into its cavity ; from which we may infer
that the production of the decidua is to be re-
garded as one of a series of changes induced by
conception in the internal genital organs, and
occurring independently of one another, rather
than as the effect of any stimulation from

the ovum, as some have supposed. Such a
decidua in fact may be compared to the sub-
ventaneous ovum of the bird.

Very little is as yet known as to the physical
circumstances (independent of malformation of
the organs) which may give rise to misplaced
gestation ; and this is not a subject which we
can hope to have illustrated by observation or
experiment. One or two cases are on record,
however, from which it might appear possible
that a violent disturbance of the body soon after
sexual union may be a cause of misplacement
of the ovum. Burdach mentions instances of
this kind : one of a cow gored by the horns of
another soon after copulation, and two instances
of the human female in which sudden fright
in the same circumstances was followed by
ovarian conception.*

In endeavouring to apply such mechanical
explanations, we ought, not to forget that in by
far the greater number of cases sudden motion
does not appear to disturb the natural perform-
ance of all those actions by which the ovum is
securely lodged in the uterus in the natural
way.

Circumstances influencing the liability to
conception. — The circumstances which influence
the liability of the female to conception are so
various and so little determined that our re-
marks on this subject must be very short.

The healthy condition of the female is of
course an important circumstance in reference
to conception, but we do not know in how far
a robust constitution or high state of health is
favourable or the reverse to the occurrence of
conception. Some women, it would appear,
(perhaps those of a spare habit of body and
languid powers of constitution) are most liable
to fall with child when in their strongest and
best state of health, while weakness in others
seems to induce conception. Among animals
it is known that high feeding sometimes pre-
vents pregnancy, and the same is the effect of
the opposite extreme of starvation.

The regularity of the menstrual discharge is
one of the most important circumstances which
favours the liability of women to conception ;
perhaps more from its being an indication of
the general healthy state of the generative or-
gans than from any influence exerted by the
menstrual change itself. Many circumstances,
however, seem to render it probable that women
are more liable to conception within a few days
after the cessation of the menstrual flow than at
any other period of the interval, and accordingly
there are many accoucheurs who regulate their
calculations of the time of birth from this cir-
cumstance, dating the commencement of utero-
gestation from a period within a week after the
cessation of the last menstrual discharge. We
do not know with certainty upon what circum-
stances this influence of the menstrual function
depends ; but it seems reasonable to suppose
that it is connected with that state of excitement
and sanguineous congestion in the ovaries and

* See Lallemand's Observat. Patholog. 1818,
and Diet, des Scien. Med. xix. ; also Grasmeyer
de conceptu et fecundatione humana, 1789.

GENERATION.

457

rest of the generative organs which usually at-
tend on menstruation. There seems to be very
little reason to believe, as some do^ that there
is a greater than ordinary liability to concep-
tion immediately before the commencement of
menstruation.

Lactation in the greater number of women
prevents conception for a time, generally for
from six months to a year, but in other women
seems to have no effect.

It is very obvious that the state of mind of
the female has very little to do with conception,
as it is well known that conception * occurs
where there is no love, no desire, in pain, in
sleep, and in the state of insensibility; and it is
equally well established that sexual feelings
are not necessary for the occurrence of concep-
tion, although it is possible that they may in
some instances indirectly assist. It is worthy of
remark that there are examples of individuals
of opposite sex whose marriage has been barren,
both having had children with others.

Sigru of recent conception in woman. — Before
concluding the subject of the changes in the in-
ternal generative organs of the female which
follow fruitful sexual union, let us recapitulate
shortly the principal circumstances which may
be considered as evidence of conception having
recently occurred in the human female.

In the first place, there is no one point of
evidence which is conclusive in the early period
of gestation excepting the finding the ovum or
foetus; and here we must be on our guard
against confounding the mole, or such pro-
ductions which occur in the virgin, with the
true ovum. The other signs of conception
afford little satisfactory evidence singly, though
they are important when several are conjoined.

The signs of conception may be distin-
guished into those which in some measure
affect the whole system, which may be called
constitutional or general, and those which are
more strictly local, or affect principally the
generative organs.

The more general signs are —

1. The interruption of the menstrual flow at
the usual period when there is no other obvious
cause for it.

2. Fulness and enlargement of the breasts,
and vascularity of the areola surrounding the
nipple.

3. Derangement of the functions of the
stomach ; frequent nausea and even vomiting,
especially in the morning, with depraved ap-
petite, headache, &c.

4. An accelerated pulse, and some febrile
symptoms.

The local signs are —

1. A slight enlargement and increased vas-
cularity of the uterus.

2. The closure of the mouth and cervix by
a peculiar viscid secretion.

3. The existence of the commencing decidua
or substance from which that membrane is
formed.

* See the amusing speculations of the phrenolo-
gists on this subject.

4. A vascular condition of the ovary, with
very much enlarged vesicles, a ruptured
vesicle or corpus luteum, and an increased
vascularity or enlargement of the Fallopian
tubes.

Such local signs can only be obtained by the
examination of the body after death. When
the greater number of them co-exist and have
been attended with the more general con-
stitutional signs, there is strong presumptive
evidence of conception having occurred. But
nothing short of the appearance of the child
either passed in abortion or found after death
would entitle us to conclude with certainty
that conception had taken place, until those
more obvious signs, which are found after the
period of quickening, make their appear-
ance.

§ 2. As regards the male organs.

Fecundation. — In continuing the detail of
the phenomena which accompany or succeed to
fruitful sexual union, we come next to the con-
sideration of the process of fecundation. We
shall begin this subject by a sketch of the
nature and properties of the product of the
male generative organs, viz. the seminal or
spermatic fluid, and afterwards state the more
important facts which appear to throw light
upon the mechanism of the remarkable in-
fluence exerted by that fluid on the ovulum
produced by the female.

Properties of the seminal fluid. — The se-
minal product of most animals is a whitish
fluid, which to the naked eye appears homo-
geneous or nearly so ; but in the human spe-
cies and some of the higher animals, the
seminal fluid or substance, ejaculated from
the male organs during sexual union, con-
sists of two parts of different consistence and
appearance ; in the human species, the one
being of a pale milky colour and more fluid,
the other clearer, semi-transparent, and more
of the consistence of thick mucilage.

The seminal product is derived from several
sources. A part comes directly from the tes-
ticle, some is discharged from the vesiculae
seminales, and with the fluid from these
sources is mixed at the time of emission a
certain quantity of the product of the secre-
tion of the prostate body and Cowper's glands :
but it is by no means well ascertained from
which of these organs the two kinds of sub-
stance above alluded to are respectively de-
rived. The more fluid and milky portion is
first ejected; the gluey or clear mucilaginous
parts, frequently collected into small hard
masses, are more abundant in the portion
which is last emitted.

Several circumstances render it highly pro-
bable that a considerable quantity of the fluid
emitted during sexual union is derived directly
by secretion from the testicle. With a view
to the illustration of this, De Graaf performed
the experiment of tying the spermatic ducts
of a dog immediately before coition, and found,
on examining them afterwards, that they were
much distended by the accumulation of semi-
nal fluid in the part of the vasa deferentia in-

2 H

458

GENERATION.

tervening between the ligature and the testicle.
It may be remarked, however, there are no
vesiculae seminales or reservoirs of semen in the
dog, and the result of such an experiment can
hardly with justice be applied to the human
species. On the other hand, it may be re-
marked that in man, while the testicle con-
tinually secretes a small quantity of semen,
and probably a larger quantity during venereal
excitement, it is obvious that the vesiculae
seminales serve as reservoirs in which the
seminal fluid accumulates ; for when in the
dead body fluids are thrown into the vas de-
ferens, they pass into the seminal vesicle of
the same side and distend it before issuing by
the orifice leading into the urethra. The se-
minal fluid after being secreted probably
follows in the living body the same course;
and from this circumstance as well as the
suddenness of emission, it is reasonable to
infer that the greater part of the ejaculated
semen, though formed in the testicles, comes
in man immediately from the seminal vesicles.

The seminal vesicles we may suppose then
always to contain a certain quantity of seminal
fluid in the state of health. The accumu-
lation of semen in these vesicles relieves the
pressure which otherwise would distend too
much the secretory and excretory ducts of the
testicle, and the seminal vesicles are them-
selves relieved either by the sudden evacuation
of their contents from time to time, or by the
gradual absorption of the seminal fluid by the
absorbents or bloodvessels.*

There is also reason to believe that the
mucous lining of the seminal vesicles secretes
a mucous fluid which is mixed with the
prolific product of the testicles. In some
animals, indeed, the vesiculae seminales open
separately from the vasa deferentia and dis-
charge by their excretory duct a fluid peculiar
to themselves.

The impotence caused by castration or by
the ligature of the spermatic vessels suffici-
ently proves, that the testicles are the only
source of that part of the emitted fluid upon
which the fecundating power depends.

The properties of the fluid supposed to be
derived from the prostatic body and Cowper's
glands have not been satisfactorily examined.

The quantity of the seminal fluid emitted du-
ring sexual union varies in man from one to two
or three drachms. The seminal vesicles are not,
however, emptied at one emission, and, accord-
ing to Haller, when by repetition this comes to
be the case, two or three days are required in
man to fit them again for reproduction by a
new supply of fluid.

Chemical properties of the spermatic fluid. —
On cooling immediately after emission, the
seminal fluid jellies slightly, but in twenty or
twenty-five minutes it becomes more fluid

* This absorption of semen into the general cir-
culation is conceived, not perhaps on very sufficient
grounds, to cause some of the peculiarities of the
male animal at the time of breeding ; to render
the flesh rank and unfit for eating j more readily
putrescent, &c.

than at first, — a change which does not appear
to depend upon the absorption of moisture from
the atmosphere, as its weight is diminished
rather than increased.

The chemical properties of the seminal fluid
have been examined in man and several ani-
mals. It is generally considerably heavier
than water, has a peculiar odour, which in-
creases on keeping, is alcaline from the first,
and gives off ammonia when heated. Left at
rest for some time, it deposits crystals of phos-
phate of lime.

According to the analysis of Vauquelin
human seminal uid consists of the following
ingredients : —

Water 90

Animal mucus 6

Free soda ^.... 1

Phosphate of lime 3

Peculiar animal principle —

100

In the spermatic fluid of the horse, Las-
saigne has detected, besides the above-men-
tioned ingredients, the following substances : —

Muriates of potassa and soda,

Phosphates of lime and magnesia,

Peculiar animal matter called spermatine.
The milt of fishes, particularly that of the
carp, analysed by Fourcroy and Vauquelin,
contains —

An oily and saponaceous matter,

Gelatine,

Albumen,

Muriate of ammonia,

Phosphate of lime,

of magnesia,

of potassa,

• of soda.

Phosphorus in such quantity as to emit

light in the dark.

The semen is fluid in almost all animals.
In some of the lower animals it is not so, but
granular and crumbling. In the greater num-
ber of animals the fluid is of a white milky
appearance and thinner consistence than in
man, presenting in fishes the appearance of an
emulsion of yolk of egg in milk.

In respect to its mode of discharge there
are also many varieties dependent on the
structure of the generative organs. In the
lowest animals the testicle alone exists of the
genital organs, and the secretory apparatus
of this organ possesses a remarkably simple
structure, consisting in many of a number
of cceca or elongated follicles which pour
the product of their secretion into a com-
mon duct. In the cuttle-fish a very curious
modification exists in the mode of discharge
of the seminal fluid; it being inclosed in
small parcels in long-shaped transparent firm
cases, somewhat like small phials. These
cases are about three quarters of an inch in
length, and are formed in the course of the
vasa deferentia by an apparatus specially pro-
vided for the purpose: they are stopped at
one extremity, and at the other are closed by

GENERATION.

459

a lid somewhat like the cork of a phial, be-
tween which and the main body of the case a
spiral spring is interposed, so contrived that
when the case is immersed in water the spring
expands, forces off the top of the case, and
allows the seminal fluid to issue from the
interior.

We must refer to the anatomical articles for
an account of the varieties of structure of the
male generative organs in different animals.
In some of those in which the vesiculae semi-
nales are wanting, as in the familiar example
of the dog, copulation is necessarily longer
than in others. Very little is known as to
the uses of the prostatic body or Cowper's
glands. See GENERATION, ORGANS OF.

Spermatic animalcules. — The most remark-
able circumstance undoubtedly which is known
respecting the spermatic fluid, is the almost
constant existence in it of an immense number
of minute moving bodies of the nature of In-
fusorial animalculae, — the well-known and
celebrated spermatic animalcules, which, since
the time of their first discovery in 1677, have
excited the curiosity and speculative fancy of
many naturalists.*

The spermatic animalcules have been found,
at one time or other, in the semen of almost all
the animals in which they have been sought
for,f but at that period of their life, and in that
season of the year only, when the animals to
which they belong are fit for propagation.
They are diminished in number, or even en-
tirely disappear, after very frequent emission
of the seminal fluid. They almost always
exist in the fluid secreted by the testicles, and
very often in that of the seminal vesicles, into
which they have doubtless been introduced
along with the fluid of the testicles.

From these circumstances, as well as others
to which we shall afterwards advert, there is
good reason to believe, that the existence of
seminal animalcules in the male product is in
some way or other intimately connected with
the integrity of its fecundating property ; if not,

* Haller states as his conviction, that Ludwig
Hamm (then a student at Leyden) was the first
discoverer of the seminal animalcules in August of
1677. Leeuwenhoek claimed the merit of having
made the discovery, in November of the same
year, and in 1678, Hartsaker published an account
of them, professing to have seen them as early as
in 1674. A great deal has since been written re-
garding them. Needham, Buffon, Der Gleichen,
Spallanzani, Prevost and Dumas, and Wagner,
may be mentioned as those who have devoted
most attention to these curious little animals. Our
remarks are taken chiefly from the investigations
of the three last authors, as well as from original
observations.

t The class of fishes are stated by Messrs. Pre-
vost and Dumas to form an exception to this
remark, these observers not having been able to
discover any seminal animalcules in the seminal
fluid of fishes ; but they are stated to have been
seen by older authors (see Haller's Elementa, vol.
vii. p. 521); and from the latest investigations it
appears that they exist, though of a form different
from the spermatic animalculae of most other ani-
mals. The author has seen them very clearly in
the seminal fluid of the Perch, and one or two
other fishes. See Fig. 51, p. 112, vol. ii.

as some are inclined to hold, the essential cause
of it.

The form, appearance, and size of the semi-
nal animalcule are different in almost every
different animal, and in each species of the
more perfect animals the kind of animalcule
seems, like that of Entozoa, to be constant and
determinate. While, therefore, these little crea-
tures, by their minute size and their general
structure and appearance (so far as these are
known), are distinctly animals of the infusorial
kind, their residence in other living animals
entitles them to be classed among the Entozoa.
Baer considers them as most nearly allied to
the Cercaria among the Infusoria, and gives
them the very appropriate name of Sperma-
tozoa.

In what we have hitherto said of the seminal
animalcules, we have drawn our description
principally from what has been observed in
quadrupeds and birds, but they differ consi-
derably from these in some of the inferior
animals. Czermak* holds that these various
forms may be referred to three principal heads,
viz. : —

1 . Cephaloidea, merely rounded bodies with-
out tails, existing in fishes and some Annelida.

2. Uroidea, thread-like, in Mollusca, Am-
phibia, and some birds.

3. Cephal-uroidea, consisting of a globular
and a tail part, in Mammalia, Birds, and In-
sects.

The first of these kinds of Spermatozoa are
like the Monades among Infusoria, the second
resemble the Vibriones, and the third, as has
been already remarked, the Cercaria.

It is important to remark that, in so far as
has as yet been ascertained, the form and size
of the spermatic animalcules do not bear any
intimate relation to the animal in which they
exist, nor to the ova of the female. In respect
of form, Messrs. Prevost and Dumas state that
the head is usually of a round lenticular shape
in quadrupeds, while in most birds it is of a
long oval shape ; but in some birds the form is
the same as in most quadrupeds. The semi-
nal animalcules present nearly the same ap-
pearance in man and in the dog. Various
markings are represented in the cephalic por-
tion of the animalculae of some quadrupeds by
Messrs. Prevost and Dumas, but these, we
are inclined to believe, are not constant, and
are appearances which have arisen from acci-
dental circumstances.

In respect to size, there appears to be still
a greater want of correspondence. The semi-
nal animalculae are said not to be larger in the
whale than in the mouse. They are very much
larger in Insects, Mollusca, and others of the
lower animals than in Man. In the snail they
are fifty-four times longer than in the dog, and
considerably larger in the mouse than in the
horse

The following table exhibits approximative^
the sizes of the spermatic animalculae of some

* Beytrage zu der Lehre von der Spermatozoen,
2 n 2

460

GENERATION.

of the more common animals in parts of a

line:*—

Parts of aline,
Helix pomatia .................. '410

Lymneus stagnalis .............. -300

Aquatic Salamander ............ -200

Viper ......................... -050

Polecat

Guinea-i

Mouse . . ................... V '040

Linnet

Sparrow

Hedgehog ................... \

Anguis fragilis ................ S

Bull ........................... -028

, *.

-Fg f

Mii r

•030

Goat

Rabbit

Common fowl '016

Frog -013

L)og )

Man (according to Der Gleicheri) J

Man (according to Buffon) "006

Gruithuisen states that he has observed the
seminal animalcules to propagate by division
of their bodies, or fissiparous generation. But
we are far from attaching implicit faith to all
that has been stated even as matter of observa-
tion regarding these bodies.

W?e ought not to omit in this place to state
another and a different view which has recently
been taken of the nature of the moving particles
of the semen ; we mean that of G. Treviranus,
who, founding chiefly upon observations made
by himself in the lower animals, as Mollusca
and Insects, adopted the opinion that these
particles are not independent animals, but ana-
logous in their structure and properties to the
fibrils and particles occurring in the pollen of
plants. Their motion he seems to regard as of
the same kind with that discovered by R. Brown
to exist in infusions of these and other minute
floating particles, and not as of an animal or
spontaneous kind. He deduces this conclu-
sion principally from the alleged observation
that the motion of the so-called animalcules is
not the same as that of ordinary Infusoria, but
differs from it in this respect, that it is simply
vibratory and constant, and not interrupted by
any of those stops or pauses and changes from
place to place which are held to indicate spon-
taneity in the motions of Infusoria.f

Some of the facts already stated by us shew
the fallacy of the opinion of Treviranus. Baer,
who regards the Spermatozoa as distinct living
animals, holds that Treviranus has observed
only an imperfect condition of the animalcule,
and states in the work of BurdaehJ some addi-
tional observations of his own made in the

* This table is taken principally from the mea-

snail, which promise, when pursued further, to
remove some of the difficulties respecting the
nature of these bodies. Baer states that he has
observed the head and tail parts to become
separated from one another, and both these
parts, but especially the tail, to move about
after separation. Baer has observed also that
there are various stages of formation and change
of the seminal animalcule, during which not
only their form but also their motions undergo
remarkable alterations, and he supposes that
Treviranus must have observed the spermatic
animalcule of the snail and mussel in one of
these stages only. Observations made* by
the author of this article and by Dr. Sharpey in
the frog, seem to bear upon this point, and to
be in some degree confirmatory of the view
given by Baer. We have almost invariably
found, in observing the seminal fluid of the
frog in the spring or summer, that the animal-
cules contained in it are not of the kind de-
scribed by authors in this animal, viz. with
both head and tail, but of the thread-like form
only. These were collected in bundles in the
thick part of the fluid, and generally moved
with a continued vibration such as we have
previously described. In the thin part of the
flnid there were a few round-shaped or monad-
like infusoria. Occasionally it happened that
when water was added to the thick part of
the fluid, and the bundles of the thread-like
bodies were artificially broken down, some of
them moved progressively through the fluid by
the undulatory riggling of one of the extremi-
ties ; and during their motion we were surprised
to see some of those, which, when at rest, ap-
peared to be destitute of any cephalic part, fre-
quently assume the appearance of a head. This
phenomenon we remarked to be owing to the
circumstance that the end by which the animal-
cule moved forward was bent backwards on the
middle of the body, so as at one time to give
exactly the tadpole-like appearance which is
represented as a head in their plates by Messrs.
Prevost and Dumas. There could be no doubt
that this was the case, for in some, in which at
one time the end was so closely joined to the
body that it could not be seen, at another it
loosened from it, and the thread-like animal-
cule still continued to progress in the fluid
with its curve forwards, and the two ends (of
unequal length) floating separate and loose.
The author has observed nearly the same phe-
nomena in the spermatic fluid of the pigeon.
Lastly, the observations of R. Wagner on the
spermatic fluid of the Guinea-pig seem to prove
more decidedly than any of the previously men-
tioned facts that the spermatic infusoria are
subject to remarkable changes of form at dif-
ferent periods, and that they even go through a
regular gradation of development.

The discrepancy of these observations makes

These observations were made five years before

surements of Prevost aud Dumas given in their the publication of this article. For further infor-

excellent account of the seminal animalcules pub- mation respecting the Spermatozoa we refer the

lished in the Annalcs des Sciences Naturelles. reader to the articles ENTOZOA and SEMEN ; in the

t See a paper in Tiedeinann's Zeitschrift, vol. v. last of which Mr. Wagner, who has investigated

part 2, 1835.

t Vol. i. second edition.

their nature with great success, will fully explain
his views.

GENERATION.

461

it apparent that we ought in the present state of
our knowledge to be very cautious in making
any general conclusion regarding the nature of
the spermatic animalcules. It appears to be
fully proved that some such animalculae always
exist in the seminal fluid of animals when they
are fit for propagation ; but it is by no means
certain that they belong exclusively to the fluids
which are the product of secretion in the tes-
ticle, for animalculae very similar to them in
general appearance and in motions are to be
found in various other fluids and organs of
animals. In all those parts of the body in
which mucous secretions are accumulated, ani-
malculae are formed, and in some of the lower
animals the Cercariae of intestinal mucus are
hardly to be distinguished from the animal-
culae of their seminal fluid.

Nor is it well ascertained that these animal-
cules belong exclusively to the fluid of the tes-
ticle, and do not sometimes occur in the secre-
tions of other parts of the generative organs.
They exist no doubt frequently in the seminal
fluid of the testicle, but some recent observa-
tions seem to shew that they are frequently
imperfect in the fluid of that organ, and that in
some animals at least they are not fully formed
and do not acquire their powers of active mo-
tion till some time after the seminal fluid is
secreted, and when it has passed from the tes-
ticle into other parts of the generative organs.
On this account some hold, and with good
reason, that they are to be regarded as the pro-
duct of reciprocal changes of the ingredients of
the seminal fluid on one another, rather than as
secreted along with that fluid directly from the
bloodvessels of the testicle, as others have sup-
posed.

In conclusion, we would remark that in
regard to the seminal animalculae having both
the body and tail, such as those that may be
seen in the dog, cat, rabbit, or other quadru-
peds, and which were described by the dis-
coverers and early observers of the seminal
animalculae, no one who has had an oppor-
tunity of observing them carefully with a good
lens magnifying three or four hundred diame-
ters can doubt for a moment that they bear a
close resemblance to some of the Infusoria, and
that both from their structure and motions they
are with as much justice as the Infusoria to be
regarded as distinct animal beings. With re-
gard to the other kinds above mentioned, or the
changes they may undergo in different stages
of their existence, farther investigations appear
necessary to enable us to form an opinion.

Although the spermatic animalcules, like
other Entozoa, are formed only in living ani-
mals and may be regarded as dependent for
life on those animals in which they occur, yet
they retain their life for a time after they leave
the body. Thus the spermatic animalcules of
the Polecat, which Prevost and Dumas ob-
served with much attention, continued to move
for fifteen or twenty minutes on the object-
stand of the microscope ; and these experimen-
ters state that when the seminal fluid is allowed
to remain in the genital organs, the animalcules

continue to live for fifteen or eighteen hours
after the death of the animal. Their motions
cease instantly when a strong electric spark is
passed through the fluid containing them.

Immediately after the discovery of the semi-
nal animalcules, they were made the subject of
very fanciful hypotheses, and were conceived to
throw quite a new light upon some of the ob-
scure parts of the generative process. To the
supporters of the theory of pre-existing germs,
their discovery opened up the prospect of being
able to trace backwards one link more than had
previously been done in the chain of life which
connects the parent and offspring. By some
they were considered as the cause of sexual en-
joyment or venereal propensities. By others,
the animalculae were held to be of different
sexes, and, accord ing as one or other gained the
egg during fecundation, to give rise to a male
or female offspring, and thus to determine its
sex. They have been supposed by others to
form the first rudiments of the foetus or lay
the foundation in the germ of the egg from
which the offspring is afterwards developed,
and fecundation has thus been resolved into
the simple passage of a seminal animalcule
into the germinal part of the egg; and finally,
one or two of the most fanciful of such dream-
ing physiologists have (as we had occasion to
remark at a former part of our article) not failed
to perceive on a sufficiently minute inspection
of the animalcule, that it already possessed
all the organs belonging to the mature con-
dition of the animal in the seminal fluid of
which it existed; compressed no doubt into
a very small space, but from which it was easy
to suppose the offspring to be formed by evo-
lution.*

Such notions require no refutation. Let us
rather pass now to the inquiry of how far ob-
servation and experiment have tended to throw
light upon the essential circumstances upon
which the fecundating property of the seminal
fluid depends.

The nature of the change which confers
upon the egg the power of production is entirely
unknown to us,and we already remarked towards
the commencement of this article that this action
is to be ranked among those vital operations of
the animal economy which are placed beyond
the reach of our means of investigation. We
should with equal prospect of success proceed
to inquire how life originates and is maintained
in the parent, as to investigate the secret man-
ner of the transmission of the vital spark from
the parent to the offspring. The physiologist
who would study this subject must therefore
limit his inquiries in this as in other departments
of his science to the search after those condi-
tions or chain of circumstances which appear
to be essential to the occurrence of the parti-
cular change or phenomenon which is the
object of his investigation.

Our present object, then, is not to investigate
the nature of the change by which the living

* Gaultier, Generation des Homines et des
Aniniaux. Paris, 1750.

462

GENERATION.

productive power is given to the egg, but to
endeavour to establish what are the essential
conditions of fecundation.

Difference between the fecundated and unfe-
cundated ovum. — In the first place, in reference
to this subject, it would be interesting to know
whether any material difference exists between
the structure of the fecundated and unfecun-
dated egg.

In the common fowl we have seen that the
whole substance of the egg, the yolk and ger-
minal portion, the albumen, shell, and mem-
brane, may be formed in the ovaries and oviduct,
and excreted from the body of the hen without
any connection with the cock ; but such an
egg, though apparently the same in structure
with that which is laid after connection with
the cock, when subjected to the requisite heat,
undergoes none of the changes of development
which incubation induces in the fecundated
egg, but only passes into chemical decomposi-
tion like any other dead animal substance.

Did any difference of structure exist between
the fecundated and unfecundated egg, we
should be disposed to look for it first in that
part of the egg which is more immediately con-
nected with the new being, viz. in its germinal
portion ; but we regret to say that the investiga-
tions of naturalists have not as yet pointed out
any marked difference in a satisfactory manner.
Malpighi, it is true, long ago pointed out a
difference in the structure of the cicatricula of
the egg of the common fowl which had had
connection with the cock, and those of the hen
living single, and the observations of this author
were afterwards confirmed by Prevost and
Dumas. In the impregnated egg the cicatri-
cula is a well-defined whitish spot, with a re-
gularly formed transparent area in its centre ;
while in the unimpregnated egg there is no re-
gularly shaped transparent area, but rather a
number of small irregular clear spaces scattered
over the surface of the cicatricula. We fear,
however, that this appearance of irregularity
exists as well in some eggs that have been laid
after connection with the cock, and that the
shape or appearance of the cicatricula can
scarcely be depended upon as informing us
whether an egg has been fecundated or not,
since that appearance is much influenced by
the state of the nucleus or white matter of the
yolk situated below it, as well as by the state
of the cicatricula itself. This subject is worthy,
however, of the most accurate investigation, as
it appears to offer the prospect of affording
some information on this very obscure part of
the generative process.

In the ovarian ovulum, the vesicle of Pur-
kinje, it will be recollected, occupies the centre
of the cicatricula; and this vesicle exists in the
ovulum so long as it remains within the ovarian
capsule, whether the hen have connection with
the cock or not. In the impregnated fowl the
germinal vesicle of Purkinje bursts, and leaves
the transparent area in the centre of the cicatri-
cula at the time when the ovulum passes from
the ovarian capsule into the oviduct ; but it re-
mains to be known if the same is the case, or

what phenomena ensue upon the escape of the
ovulum from the ovarium in the fowl which is
entirely separated from the cock.*

We do not know with certainty what befalls
the vesicle of Purkinje in the ovulum of Mam-
malia at the time of its escape from the ovarium.
The analogy of all oviparous animals is strongly
in favour of the supposition that it bursts in the
same manner. M. Coste states that it does not
burst, and Valentin supports an opposite view.
While, therefore, we feel disposed to adopt
the opinion that the seminal fluid, in fecunda-
ting the egg, operates its peculiar change chiefly
on the germinal part, and that the bursting of
the germinal vesicle is very probably connected
with the change of fecundation, it must be ad-
mitted that further observations are still want-
ing to afford a satisfactory proof of the correct-
ness of these hypotheses.

Is material contact of the semen and ovum
necessary for fecundation'? — No one has ever
discovered any of the seminal fluid within the
egg : the most minute observation does not de-
tect any appearance of this. A question then
naturally presents itself in reference to the sub-
ject of our present inquiry, viz. whether it is
necessary that a certain quantity of the sub-
stance of the seminal fluid should be brought
into actual contact with the egg in order to
cause its fecundation 1 and if so, in what man-
ner and in what part of the female organs such
contact is brought about?

Were we to look no further than to the
manner in which fecundation is effected in
many of the inferior animals, we might be in-
duced at once to form the opinion that the mere
contact of a certain quantity of the seminal fluid
with their ova, in whatever way brought about,
is all that is necessary for producing their fecun-
dation. Thus, in the greater number of fishes
the milt or seminal fluid of the male is shed
over the spawn of the female after it is laid in
water, without there being any nearer sexual
intercourse; the fecundation is external to the
body of the female, and we thus know with
certainty that the ova and the seminal fluid are
the only parts immediately concerned in the
process. The same is the case in the common
frog, in which there is copulation ; for in that
animal, although the male and female remain
united firmly together during a longer period
than any other kind of animal, yet this union
is not a means of producing fecundation, but
rather of promoting the discharge of unim-
pregnated ova from the generative system of
the female. There is in fact no true sexual
union : the spawn is laid by the female un-
fecundated, and the male (separating then in
general from the female) sprinkles seminal fluid
on the ova floating in water.

External and artificial fecundation. — The
mode of fecundation just now mentioned sug-

* We have long had the intention of instituting
a series of observations comparing the changes of
the impregnated and unimpregnated ovum in the
oviduct, but have not vet had an opportunity, and
we recommend it to those who may be anxious to
engage in the investigation of this subject.

GENERATION.

463

gested to Spallanzani* the ingenious expe-
riment of artificial fecundation, which he first
performed, and which furnished the most con-
vincing proof that could be obtained, that, in
such animals as the frog, sexual union is not
essential to fecundation, and that, when the
ova are ripe and the seminal fluid of the suit-
able quality, the mere contact of the male and
female products is sufficient to confer fertility
upon the ova.

Spallanzani opened very many female frogs
at the lime of propagation, but before they had
laid any spawn, and consequently before im-
pregnation could have occurred, and he satis-
fied himself that the ripest ova extracted from
the oviduct, and placed in water, gradually
passed into putrefaction without undergoing
any of the changes of development ; while some
of the same ova, upon which he had sprinkled
some of the seminal fluid taken from the body
of the male, and placed in similar vessels of
water, had tadpoles formed from them in the
same manner exactly as those which were fe-
cundated by the male frog itself.f

The same experiments were performed by
Spallanzani on toads and newts with exactly
the same result.

Spallanzani, in order to avoid every fallacy,
allowed the female to remain in union with the
male, and to lay her spawn in the natural way,
preventing only the access of any of the seminal
fluid of the male to the ova, by tying up the
hinder part of the male's body in oiled silk, and
these ova were alike barren, unless he added to
them some of the seminal fluid in the artificial
mode.

TreviranusJ mentions the performance of the
experiment of artificial fecundation in Fishes,
viz. on the spawn of the Salmon, Trout, and
Carp, by Duhamel and by Jacobi. Jacobi's
experiments were repeated by Dr. Walker of
Edinburgh ; and very recently it has again been
performed on the spawn of the Tench and
Bleak by Rusconi of Pavia. (Cyprinus Tinea
and Alburnus.)

The very complete series of experiments of
Messrs. Prevost and Dumas § on the frog
afford the most satisfactory confirmation of
those of the Abbe Spallanzani.

The following appear to be the more im-
portant results deducible from these two sets of
experiments.

1st. That a very small quantity indeed of the
seminal matter is requisite for the fecundation
of the ovum.

2d. That dilution of the seminal fluid with
water within certain limits does not impede,
but rather is favourable to its operation.

3d. That the absorbent power of the albumi-
nous or gelatinous matter which surrounds the
black yolk is highly useful in bringing the
seminal substance in contact with the yolk,
where it is obvious its effect must be produced.

* Dissertazioni di fisica animale, &c.

t This experiment the author has more than once
performed with a similar result.

J Erscheinungen und Gesezte des Organischen
Lehens.

$ Annal. des Sciences Nat. torn. i.

This albuminous covering, corresponding to the
white of the bird's egg, possesses the remark-
able property of absorbing water, somewhat
like gum tragacanth, in a determinate quantity,
and thus increases greatly in bulk after being
laid in water. In the experiments referred to,
the absorption of the water by the jelly was
fully demonstrated by the immersion of the ova
in coloured water, and it was found also that
the experiment of artificial fecundation suc-
ceeded best when the ova had not been im-
mersed in water for any considerable time pre-
vious to the addition of the seminal fluid. The
fecundation was less certain the longer the ova
were allowed to remain in water before the ad-
dition of the semen ; and it was shewn that this
did not depend simply on the length of time
of the separation of the ova from the body of
the parent, by the fact that ova taken from ,
the oviduct and kept without moisture re-
tained their susceptibility of being fecundated
for a much longer period, as sixteen or twenty
hours.

4th. That the seminal fluid of the frog retains
its fecundating power for about thirty hours
after it has left the body of the male.

5th. Attempts were made by both the expe-
rimenters above quoted to ascertain, by way of
experiment, whether the seminal animalcules
are indispensable to fecundation. Spallanzani
came to the conclusion that the seminal fluid
did not lose its peculiar powers although de-
prived of its animalcules, or although the ani-
malcules were dead ; but it must be admitted
that the means employed by that observer to
ascertain the presence or absence of the seminal
animalcule were inferior to those we possess
in more recent times. Messrs. Prevost and
Dumas, who, it has already been remarked,
consider the animalcules as the most important
part of the seminal fluid in reference to its
fecundating properties, state that they found in
their experiments, that that part of the seminal
fluid which had been subjected to a very careful
filtration, and which had thus been wholly de-
prived of its animalcules, had lost all fecunda-
ting power, while the substance which remained
in the filter, and which was rich in animalcules
when diluted with water, possessed the same
powers of fecundation as the pure seminal fluid.
We think this experiment requires repetition
and some modifications, for other ingredients,
besides the animalcules of the seminal fluid,
might be retained on the filter.

6th. Both Spallanzani and Prevostand Dumas
have attempted to estimate the quantity of
seminal fluid required for the fecundation of a
certain number of ova, and the latter observers,
pursuing their favourite idea to the utmost, have
even endeavoured to calculate the number of
animalcules which are necessary for the fructi-
fication of one or more ova. In Spallauzani's
experiments two grains of the semen of the
toad fecundated one hundred and thirteen
ova. Five grains of semen were mixed with
eighteen ounces of water; the point of
a needle dipped in this was made to touch an
egg for an instant and produced fecundation.
Hie proportion here might be estimated as

464

GENERATION.

semen 1, to egg 1,064,000,000. The addition
of a larger quantity of semen, or its remaining
longer in contact with the egg, did not, accord-
ing to Spallanzani, render the fecundation more
complete than the instantaneous contact of the
wetted needle's point. Prevost and Dumas
state that they found the number of ova fecun-
dated by a given quantity of seminal fluid is
always below that of the animalculae which they
estimated that fluid to contain; and by a sim-
ple process of calculation it was easy to find
how many animalculae served each ovum. A
certain quantity of seminal fluid, for example,
containing 225 animalcules, served to fecun-
date 61 only out of 380 ova, to which it was
added, so that each ovum required about 3|
animalcules for its fecundation, or making
allowance for a few of the animalculae which
went astray into other ova, it may be stated as
three in round numbers. It will be long before
the vital processes can be traced with the arith-
metical precision displayed in this calculation.
Unfortunately for the calculations and even the
observations upon which they are founded, one
of the authors at a subsequent period published
the theory which appears to have prompted
them to revive an old and fanciful notion that
the animalcule forms the rudiment of the new
being. The animalcule, according to this hy-
pothesis, makes its way through the stiffjelly
surrounding the yolk, gains the centre of the
germinal membrane, and esconces itself there
in the very centre of that germinal membrane,
laying thus the foundation of the primitive
streak or the brain and spinal marrow of the
foBtus : its position (which is always the same)
being no doubt determined by the laws of po-
larity depending upon the electro-magnetic
properties with which, according to equally
fanciful theorists, the rudiments of the new
being in the egg are endowed.

Hitherto cold-blooded and oviparous animals
only have been alluded to ; but there are not
wanting facts which render it highly probable
that in viviparous animals also, contact of se-
minal fluid with the ovum is the essential part
of the fecundating process. Thus, Spallanzani
confined a bitch for fourteen days before the
arrival of heat, and for twenty-six days after it,
so that, during that time, it could have had no
connexion with any dog, and at the time of
the heat he injected by means of a syringe
a quantity of the dog's seminal fluid into the
vagina. The bitch brought forth three young
exactly at the usual length of time from the
period of heat; — an experiment on artificial
fecundation, which may in some sort be said
to have been performed in the human species
is the well-known instance in which John Hun-
ter recommended to a man affected with hy-
pospadiac malformation of the urethra, which
rendered intromission of the seminal fluid
impossible, the injection, by means of a sy-
ringe, of the seminal fluid 'into the vagina, —
an operation which, it is related, was attended
with complete success.

While these facts on the one hand tend to
shew that no parts of the genital organs and
no other agents are concerned in fecundation

excepting the seminal fluid and the ova, and
on the other hand afford the only positive
evidence that can be obtained, that actual con-
tact of the one with the other is necessary to
induce the change, they have appeared unsa-
tisfactory to some physiologists,who cling to the
opinion that, in quadrupeds and birds at least,
contact is not necessary, and that fecundation
may be effected either by some hidden sym-
pathy (or concurrent action taking place in
remote parts) between the external and internal
organs of the female, or that this change may
be operated by some imponderable influence
which emanates from the seminal substance, to
which the vague name of aura seminalis has
been given.

Course of the seminal fluid within the female
organs. — In pursuing our examination of the
alleged evidence upon which these and similar
hypotheses are founded, it will be necessary
to consider in this place another question,
respecting which it is difficult in the present
state of the inquiry to form a decided opinion,
viz. whether, on the supposition of the seminal
fluid and ova coming into actual contact, the
course of the seminal fluid within the female
organs of generation can in any instances be
traced, and in what part of these organs it
may be supposed to meet with the ova and
operate their fecundation.

In the first place the examples of ovarian
conceptions, or rather gestations, have been ad-
duced by some as a proof that fecundation
necessarily takes place in the ovaries them-
selves. But from what was said in a former
part of this paper, it will be seen that such a
belief is founded on an erroneous view of the
nature of these misplaced gestations, as well as
of the phenomena which occur in the ovary
after conception. There is no reason to believe,
we may repeat, that ova found developed in
the neighbourhood of the ovary have retained
their situation within the Graafian vesicle. On
the contrary, they must in all probability have
been first discharged from the ovary upon the
rupture of the vesicle, and their places occu-
pied by corpora lutea; and they may have
been fecundated either while loose in the
cavity of the peritoneum, or when they have
descended some way in the Fallopian tubes,
and meeting with the seminal fluid in the
course of that tube, have been returned to the
vicinity of the ovary by some inverted or un-
natural action of the parts.*

Although, therefore, no very decided opinion
respecting the place at which fecundation
occurs can be formed from the observation of
what are termed ovarian and tubular gesta-
tions, we are inclined to think that they shew

* We need do no more than mention here a view
taken by Sir Everard Home of the uses of the
corpora lutea, which he holds to he a means of
bringing the seminal fluid into contact with the
ovum of the Graafian vesicle. This opinion re-
quires no remark, as it will be at once perceived
that it proceeds on the assumption, shewn to be
erroneous in a former part of this paper, that the
corpora lutea are formed before the rupture of the
vesicles.

GENERATION.

465

that this process may take place, in gome in-
stances at least, in the upper parts of the Fal-
lopian tube, or even in the infundibulum.

In the second place physiologists have en-
deavoured to argue respecting the place of
fecundation from the well-known fact that,
in the common fowl, turkey, and probably
some other birds, a single connexion with the
male serves to fecundate more than one ovum,
as, for example, in the common fowl twelve
or twenty ova; and that, as there is usually only
one ovum in the progress of descent through
the oviduct at one time, we must conclude
either that the yolks or ovula are fecundated
by the rise of the seminal fluid to the ovary,
or that the seminal fluid remains somewhere
in the course of the oviduct, to be applied to
the ovum as it descends. If we exclude the
notions of an aura and sympathetic action,
the former of the above-mentioned views ap-
pears to us the most consistent with the facts
that have already come under our knowledge.
The notion entertained by Fabricius and others
that there is a receptacle for containing the
seminal fluid in the oviduct appears to be in-
correct ; and \ve find it difficult to believe that
the seminal fluid can remain dispersed through
the oviduct, or confined in any particular part
of it and retain its power of fecundation, when
we consider the manner in which each yolk
descends from the ovary and receives in its
passage the various accessory parts constituting
the albumen and external coverings. Of
course, in supposing fecundation to take place
in the ovary, there remain two suppositions
which may be entertained regarding the mode
in which the seminal fluid gains the ovula ;
for it might either pass directly up the tube of
the oviduct, or be absorbed and take some cir-
cuitous course.

In the third place, we are inclined to think
that in quadrupeds the ova must be already
fecundated before their arrival in the uterus,
that is, either in the neighbourhood of the
ovary or in the tubes, for this reason, that at
the time when the ovum first arrives in the
uterus, it has already become considerably
enlarged, and has undergone some of the
changes of development ;* and when we con-
sider how very regular and progressive these
changes have been observed to be from the
time when the ovum first enters the tubes, we
shall be disposed to conclude that fecundation
very probably takes place before then, or in the
upper part of the tubes.

In the fourth place, attempts have been
made to trace the seminal fluid in animals
opened shortly after sexual union. Most
authors agree that much of the seminal fluid

* We do not mean here to state that the parts of
the foetus have appeared, but only that changes in
the germinal membrane preparatory to the forma-
tion of the fo?tus have taken place. Nothing of
this kind has ever been found in the unimpregnated
animal, no appearance of any ovum, whicit, con-
sidering how often vesicles are burst without sexual
union, we think must have been the case had the
ovum undergone the same changes in the unim-
pregnated as in the impregnated animal until its
arrival in the uterus.

frequently flows out of the vagina soon after
coition, and Harvey, De Graaf, and Haller
were all unable to discover any traces of
seminal fluid in the uterus even of various
animals killed and opened soon after sexual
union. Haller, however, while he states this
as the result of his experiments, admits that
the means which he possessed of ascertaining
the presence or absence of the semen were im-
perfect, and he himself believed that fluid to
have entered the uterus.

Various other physiologists, also, state that
they have found seminal fluid in different
parts of the female organs. Morgagni and
Ruysch had two opportunities of examining
the body of the human female very soon after
coition, and found, on opening the uterus, a
fluid which they regarded as semen. John
Hunter states that he observed the same in a
bitch, as also did Hausmann. But in all
these instances some doubt may be enter-
tained regarding the fluid which was considered
as semen.

Prevost and Dumas, trusting to the occur-
rence of the seminal animalculae as a certain
sign of the presence of seminal fluid, state
that they have observed these animalcules, at
different periods after coition, both in the
uterus and tubes of dogs and rabbits; and it
appears to result from the careful series of
experiments performed by these physiologists
that the longer the time was which had elapsed
after coition, the farther the seminal fluid had
advanced upwards within the female genital
passages. Thus, at twenty-four hours after
coition a great quantity of animalcules were
found in the cornua of the uterus, but none
either in the vagina or farther up the tubes ;
at forty-eight hours nearly the same was the
case : on the third and fourth days there were
many animalculae still in the cornua and some
in the tubes, which continued in the dog till
the fifth and sixth days; and upon one occa-
sion only they observed a few animalcules
near the infundibulum.

Burdach and others, again, are not inclined
to place much reliance on these observations,
because animalculse of the nature of Cercariae
have been noticed in the genital passages of
female animals which had had no connection
with the male.

In the fifth place, experiments on the me-
chanical obstruction of the uterus, Fallopian
tubes, and vagina, appear of considerable im-
portance in reference to this part of our sub-
ject. Experiments of this kind were per-
formed first by Haighton,* and afterwards by
Blundell ; the results of which, making allow-
ance for the more accurate knowledge we now
possess respecting the indications afforded by
the condition of the vesicles and corpora lutea
in the ovary, may be stated as follows : —

1st. That when one of the cornua of the
uterus or Fallopian tube of the rabbit is divided
within a few hours after coition, and oblite-
ration of the tube has followed, although
corpora lutea are formed in both the ovaries

* Philos. Transact, vol. Ixxxvi. p. 173.

466

GENERATION.

(as a consequence of the rupture of vesicles),
ova are not to be found on the injured side of
the uterus, but pregnancy takes place on the
other side.

2d. When the vagina was divided in a like
manner at its upper part, although the usual
number of corpora lutea were found in the
ovaries, pregnancy did not occur. That the mere
wound itself locally, or its hurtful effects on
the constitution, did not prevent the develop-
ment of the ova, was proved by the experiment
purposely made of dividing the parts in the
same way and allowing them to reunite by
adhesion without obstruction of the tube, in
which case uterine pregnancy occurred nearly
as in the natural condition.

3d. In another set of experiments oblite-
ration of the tubes was caused to take place
at a later period, probably when the ova had
descended and may be supposed to have met
with the seminal fluid, and in these animals
pregnancy occasionally but not always oc-
curred.

It would appear to follow from these expe-
riments, that the seminal fluid does not rise in
the female genital passages immediately upon
its introduction, and not for more than a day
after coition, arid that those circumstances
which impede the rise of the seminal fluid
prevent fecundation. But they do not warrant
the conclusion that impregnation must occur
in the ovaries, since the vesicles may have burst,
their contents be discharged, and corpora lutea
formed without the seminal fluid having had
access to the ovary; a fact which is well shewn
by the interesting experiment performed by
Dr. Blundell, of producing an obliteration of
the upper part of the vagina in the unim-
pregnated rabbit, then allowing coition to take
place, and then finding, no pregnancy, but
corpora lutea in the burst vesicles of the
ovary.

These experiments appear also as of im-
portance in shewing that neither absorption of
the semen by the lymphatics or bloodvessels,
nor the passage by any other circuitous route,
nor indeed any sympathetic action established
by sexual union between remote parts of the
female generative organs, can be the means of
producing fecundation.

There are, no doubt, great difficulties in the
way of our understanding by what manner the
seminal fluid accomplishes the passage up-
wards in the genital organs of the female.
Thus, the small size of the Fallopian tubes at
once strikes us as a powerful obstacle ; but in
many animals, as, for example, in the Rumi-
nantia, there is an equally great difficulty in
comprehending how the seminal fluid gains the
uterus itself even; for in these animals the os
uteri forms a long and uneven passage, inter-
rupted by many hard cartilaginous projections,
and closed in general by a very viscid and tena-
cious mucus. But yet the seminal fluid must
in all probability enter the cavity of the uterus.*

* Burdach mentions, as supporting the view that
the seminal fluid may be absorbed by the blood-
vessels or lymphatics, and being carried into the

In conclusion, we would remark that we
must either suppose fecundation to be the
effect of the actual contact of the seminal
fluid with the ova in the upper part of the
Fallopian tube or somewhere near the ovary,
or we are reduced to form the opinion that the
action of the seminal fluid on the lower part
of the female genital organs may be twofold,
viz. first, causing the commencement of the
process of fecundation by a sympathetic in-
fluence on the upper part of the tubes, and,
in the second place, perfecting the change in
the uterus when it meets there with the ovum.
We feel inclined, in the present state of our
knowledge, to give a preference to the first of
these opinions.

Nature of the fecundating process. Hypo-
thesis of an aura, fyc. — We return now to the
consideration of the essential nature of the
change of fecundation.

The opinion that fecundation is attributable
to the agency of an aura or emanation from,
and not to the material contact of the seminal
fluid, is founded chiefly upon alleged instances
of conception having occurred in individuals
(of the human species) in whom, from unnatural
formation or disease, no direct passage existed
from the vagina or external aperture to the
internal organs, as well as upon some of the
circumstances above alluded to, as shewing the
difficulty of such a passage both in man and
animals, even in the natural condition.

No very definite idea, it may be remarked,
can be attached to the term " aura," for it has
been employed in varous acceptations by diffe-
rent authors ; one considering it as of the
nature of a gaseous or vaporific exhalation
from the seminal fluid, another denying it the
nature of a substance even of the most etherial
kind, and considering it more as a spiritual or
vital principle ; and a third regarding it as of
the nature of a nervous impression. These
discrepancies only shew us that the term aura
is to be taken rather as an expression for the
unknown agency of the seminal fluid which
causes fecundation, than as indicating its modus
operandi or the part of its substance more
immediately concerned in the action. Some
authors have, however, even referred to direct
experiment in favour of the agency of an aura.
Mondat, for example, (De la Sterilite, 4to.
edition, p. 17) states that he witnessed experi-
ments performed by Morsaqui, of Turin, with
this view, from which it was found that the
bitch could be impregnated when it was im-
possible, as he states, that the substance of the
seminal fluid could in substance pass into the
uterus or other parts. Recurved tubes, con-
taining in the closed end a quantity of the
dog's seminal fluid, were introduced into the

general circulation occasion fecundation when it •
arrives at the ovary or other parts of the internal
organs, Gasp. Bartholin, Perrault, Sturm, and
Grassmeyer. Dr. Harlan of Philadelphia, in a
volume of Experimental Essays recently published,
states that he found that the injection of semen
into the bloodvessels of a bitch put a stop to the
heat sooner than would otherwise have been the
case.

GENERATION.

467

vagina of the bitch in such a way that none of
the fluid itself could escape, but only an
emanation, vapour, or supposed aura rising
from it, and in eighteen out of thirty animals
on which the experiment was performed, with
the subsequent occurrence of impregnation.
But until these experiments shall have been
confirmed by careful and frequent repetition,
we must be allowed to doubt the possibility of
performing such an experiment in a sufficiently
accurate manner.

Spallanzani, with a view to investigate the
powers of a vapour supposed to rise from the
seminal fluid, exposed a quantity of the ripe
unimpregnated spawn of the frog for some
time in the same vessel with a quantity of
seminal fluid, the latter being placed at the
bottom of the vessel, the ova at the top, and
never was any fecundation produced ; — an
experiment, it is true, from which no more
than negative evidence can be derived, but
upon the whole more worthy of trust as being
subject to fewer fallacies than those of Mondat.
The instances in which it has been alleged
that impregnation has taken place in the human
female without there being any possibility of
the seminal fluid itself passing inwards in the
female genital passages, are of a very doubtful
nature, and liable to so many sources of fallacy,
that we feel little disposed to admit them as
grounds of proof of the agency of an aura
seminalis. In some of the cases in which it
has been found, either in the course of pregnancy
or at the time of child-birth, that the female
passages are obstructed, there is reason to be-
lieve that the closure has been produced sub-
sequent to the occurrence of conception ; and
the same may be said of those cases of ovarian
gestations in which an obliteration of the Fal-
lopian tubes has been observed. In the greater
number of such cases, it may also be observed,
the malformation of the parts has consisted in
the much contracted state of the external orifice
or some other part of the passage, rather than
in their absolute closure, so that there was
merely a difficulty and not an impossibility of
the entrance of seminal fluid. But in opposi-
tion to such vague and ill-ascertained observa-
tions, a variety of circumstances, which it is
not necessary to particularize, might be adduced,
tending to show how very easily in the human
female as well as in other animals all mecha-
nical obstructions to the entrance of the seminal
fluid into the uterus tend to prevent conception.
General conclusions respecting fecundation.
In conclusion we would remark, 1st, that
while we readily admit a veiy small quantity
indeed of the seminal fluid to be sufficient to
produce fecundation, we think that what has
previously been stated warrants the conclusion,
that material contact of a certain quantity,
however small, of the seminal fluid with the
ovum is necessary to give rise to its fecunda-
tion, and, consequently, that the hypothesis
of an aura is untenable. And for the same
reasons it follows that there are no just grounds
for holding the opinion either that fecundation
consists in a sympathetic action of a nervous
kind, or that it is brought about by the absorp-

tion of the semen into the circulatory or
lymphatic vessels of the generative system.

2d. It is sufficiently obvious that in quadru-
peds there is no exact proportion between the
quantity of seminal substance or fluid received
by the female or emitted by the male, and its
effect in producing fecundation, — a circum-
stance which points out a distinction which
ought always to be borne in mind between that
vital change on the female genital system and
the whole economy and ovum, and the simple
physical re-action which may take place be-
tween the semen and ovum themselves.

3d. We may regard venereal excitement of
the genital organs and impregnation of an
ovum as different phenomena, for though they
usually occur together, there are instances in
which they take place quite independently.

4th. The action of impregnation is to be
regarded as sui generis, or quite peculiar among
the vital processes. It is not capable of being
imitated by any other substance than the
seminal fluid, and neither experiment nor ob-
servation enables us to form the most distant
conjecture what the nature of that action may
be, which, from the influence of the male pro-
duct, confers upon the ovum a new and
independent life, and enables to give birth to
a new individual the mass of organic matter in
the egg, which, without the change of fecun-
dation, would prove altogether barren and
undergo no other changes than those of similar
dead matters. The action, however, is in some
respects reciprocal, and we cannot determine
what part either of the two agents concerned
performs in the change of fecundation : we
know only this, that unless the seminal fluid
be of the suitable composition it is ineffectual,
and that ova are susceptible of its influence
only when in that period of their evolution
when they are ripe. Nor can we with certainty
fix on what part of the egg the influence of the
male semen more immediately operates. Since
the foetus grows from the centre of the germinal
layer, it has been commonly supposed that
this is the part of the egg which is most imme-
diately affected by fecundation, but we know
nothing of this ; and it might be held, on the
other hand, that the effect of fecundation ope-
rates on the rest of the contents of the egg
in enabling them to be assimilated round the
germinal centre or rallying point of the de-
velopment of the new being.

5th. It has not yet been shewn that one
part of the seminal fluid is more necessary to
impregnation than another. The seminal
animalcules form a natural ingredient of the
fluid secreted in the testicle at the time when
it is excreted for the purposes of propagation ;
they appear to be invariably present, but addi-
tional experiments are still wanting to prove
them to be the active or essential agents of
fecundation, much more the rudiments of the
- new being within the ovum.

6th. Like others of the operations of the
animal economy, the action of fecundation is
known principally in its effects; but it seems
to be a question worthy of investigation whe-
ther, in the phenomena exhibited during fecun-

468

GENERATION.

dation, or the laws by which this change is
regulated, it be in any respect analogous in its
nature to the operation of certain poisonous or
contagious principles, as for example, the
venereal virus, vaccine matter, the contagious
principle of small-pox, measles, scarlatina,
plague, fevers, &c. The inimitable Harvey
thus expresses himself regarding the essential
nature of fecundation in different parts of the
forty-ninth Exercitation on the efficient cause
of the chicken. " Although it be a known
thing subscribed by all that the fostus assumes
its original and birth from the male and female,
and consequently that the egge is produced
by the cock and henne, and the chicken out of
the egge, yet neither the schools of Physicians
nor Aristotle's discerning brain have disclosed
the manner how the cock and its seed doth
mint and coine the chicken out of the egge."
" This," he says, " is agreed upon by universal
consent; that all animals whatsoever, which
arise from male and female, are generated by
the coition of both sexes, and so begotten as it
were per contagium aliquod, by a kind of con-
tagion." " Even also," he says, " by a breath
or miasma," referring to the fecundation of the
ova of fishes out of the body.

" The lac maris, male's milk, propagating or
genital liquor, vitale virus, vital or quickening
venom," are all names of the seminal fluid of
the male. Again, " The efficient in an egge,
by a plastical vertue (because the male did
only touch, though he be now far from touching
and have no extremity reached out to it) doth
frame and set up a foetus in its own species
and resemblance." " What is there in genera-
tion, that by a momentary touch (nay not
touching at all, unlesse through the sides of
many mediums) can orderly constitute the parts
of the chicken by an epigenesis, and produce
an univocal creature and its own like ? and for
no other reason but because it touched here-
tofore."

" The qualities of both parents are observable
in the offspring, or the paternal and maternal
handy-work may be tracked and pointed out
both in the body and soul." The first cause
must therefore be of a mixed kind. " It is
required of the primary efficient in the fabrick
of the chicken, that he employ skill, providence,
wisdom, goodness, and understanding far above
the capacity of our rational souls."

7th. In respect to the part of the female
generative system at which fecundation takes
place, it appears most probable that in quadru-
peds and the human species this change occurs
before the ovum reaches the uterus, or some
way in the course of the Fallopian tubes ;
perhaps most frequently in the upper part of
them. There is, however, probably some
variation among animals and in different cir-
cumstances regarding this point. But while
we state this as the conclusion most consistent
with facts in the present state of our know-
ledge, we ought not to omit the mention of the
more prominent facts by which it is opposed.

In some of the lower animals, fecundation
seems to extend beyond the sphere of the ova
which are ripe. In the Aphis (as was already

mentioned at an early part of the paper) the
production of young by the female goes on
for several generations (eleven) without any
sexual intercourse after that which gave rise to
the first. In the Daphnia Longispina this is
said also to be the case for twelve generations,
and in the Monoculus pulex for fifteen. The
queen-bee lays fruitful eggs during the whole
year after being once impregnated ; and in the
instance of the common fowl and some other
birds, previously referred to more than once,
if we reject the supposition of the seminal
fluid remaining in action, it seems necessary to
suppose that fecundation must occur in the
ovary, since unripe ova are acted on by the
fecundating medium at the same time with
those which are arrived at maturity and are
ready to descend into the oviduct.*

Many physiologists also believe that the
influence of the first impregnation extends to
the products of subsequent ones. Thus Haller
remarks that a mare which has bred with an
ass and has had a mule foal, when it breeds
next time with a horse, bears a foal having
still some analogy with the ass. So also in
the often cited instance of the mare which bred
with a male Quagga, not only the immediate
product, but three foals in subsequent breedings
with an Arabian stallion, and these three even
more than the first, partook of the peculiarities
of the Quagga species.

Instances of the same kind are mentioned
by Burdach as occurring in the sow and bitch ;
and it is affirmed that the human female
also, when twice married, bears occasionally to
the second husband children resembling the
first, both in bodily structure and mental
powers.

According to Hausmann, when a bitch has
connexion with several dogs (and this is gene-
rally the case during the continuance of the
heat, sometimes to the amount of twenty,) she
usually bears two kinds of puppies at least, and
the greater number of these resemble the dog
with which she first had connexion.

We feel at a loss to decide what weight
ought to be attached to these observations;
they appear to bear chiefly on the subjects
which are discussed in the next part of this
article.

V. MISCELLANEOUS TOPICS RELATING TO THE
PRECEDING HISTORY OF GENERATION.

We have deferred until now the consideration
of some topics which usually find a place in
the history of the generative function, as we
have thought it desirable to separate them from
the preceding narrative on account of the
vagueness of the facts and speculative nature
of the opinions with which they are connected.
The subject last discussed naturally leads to

* Burdach hazards the opinion that in some
quadrupeds the ova may not even be developed at
the time of impregnation, as in the Roe-deer, which
pair in July and August, but do not bear their
young till May, and the Fox, the period of gesta-
tion in which is much longer than we should sup-
pose it ought to be, judging from the analogy of
others of the Dog genus.

GENERATION.

469

the first of these topics which . we shall con-
sider, viz.

§ 1. Superfatation. — In the first section of
Part IV. it has been mentioned that in the
human female, as soon as the ovum has arrived
in the uterus, and even a short while before
that period, the passage through the mouth
and neck of the uterus is closed by a viscid
mucus, which opposes a firm barrier against the
entrance of seminal fluid, and thus prevents
the occurrence of subsequent or reiterated con-
ception. In some of the lower animals, on
the other hand, it would appear that several
consecutive conceptions not unfrequently occur,
and in some animals this may be considered as
the natural mode of generation.

It becomes a point of some interest both in
a physiological and in a medico-legal view to
determine, whether, as has been supposed by
some, the same ever takes place in the human
species.

The quadrupeds in which su perforation
(as a second conception during pregnancy is
called) is said to occur possess a uterus with
two horns, and it may be that in them the
product of the first conception has occupied
only one of the cornua of the uterus, and that
the second conception occurred upon the other
or empty side. This may be the case in the
hare, for example, which is said to be particu-
larly liable to superfoetation. In woman also,
it has been supposed that a double form of
uterus, which is present in rare instances as a
malformation of that organ, may admit of a
second conception on one side in the course
of uterogestation confined to the other. But
though this may be regarded as possible, we
are not aware that any example of the actual
occurrence of pregnancy in both cornua of
a double uterus affords a satisfactory proof
of it.

Great caution is necessary in admitting the
evidence of superfoetation, as many circum-
stances concur to render it very fallacious.
Women occasionally bear twins, or two chil-
dren differing greatly in size and apparent age ;
and many are apt at once to form the conclu-
sion from thence that the two children must
have commenced their existence or have been
generated at different times ; but it is much
more likely in most of these instances, that
the different appearance in the size and con-
formation of the children has arisen solely
from a difference in the rapidity and vigour
of their growth. In by far the greater num-
ber of such instances, the smaller of the
children bears obvious marks of being stunted
in its growth, and it is often deformed, blighted,
or dead and shrunk ; and even although this
were riot the case and the children were both
alive, a mere difference of size of children
born at the same time must be regarded as
very slight evidence indeed of so great a devi-
ation from the usual phenomena of pregnancy
as superfbetation.

Those who believe in the possibility of the
occurrence of superfcetation found their belief
chiefly upon some rare instances of the birth
of more than one perfectly developed child at

successive periods so remote from one another
that both cannot have been conceived at the
same time, and it must be admitted that these
cases, if correct, go far to prove the possibility
of superfcetation.

In reviewing the cases of alleged super-
foetation two questions at once present them-
selves for consideration, viz. 1st, whether a
second conception may take place within a few
hours or days after the first, or we mav say at
any period before the ovum is settled in the
uterus; and, second, whether this may occur
at a later period, as at two, three, four, or more
months after the first conception.

The puppies of a bitch, we have already
mentioned, generally bear a resemblance to
more than one of the dogs with which she has
had connexion during the period of heat, and
this period may extend to eight or nine days.
A mare, which had been covered by a stallion,
was five days afterwards covered by an ass,
and bore at the usual time twins, one of which
was a common foal, the other a mule.*

Women have been known to bear two chil-
dren of different colour; and in one of these
instances the mother is said to have confessed
to having admitted the embraces of a black
servant a few hours after her husband, who was
white.

Facts like these seem to shew that sexual
intercourse limited to an interval of a few days
(most probably before the uterus has been
closed by the decidua) may produce super-
fcetation. But we would remark that, although
it may be that the mechanical obstruction of
the decidua opposes an obstacle to the passage
of semen upwards, or the descent of a new
ovum into the uterus, there is obviously ano-
ther cause why superfcetation should not occur :
we mean that fundamental change in the con-
stitution which is induced by pregnancy,
similar to that which continues in the majority
of women during lactation. But for such a
constitutional change, we conceive continual
derangement of the function of utero-gestation
would attend that process in consequence of
the recurrence of some of the more general
symptoms of conception, even although a
lodgement of a new ovum in the cavity of the
uterus were impossible.

The following cases serve to illustrate the
nature of the more important facts on record
which do not admit of an explanation, except-
ing on the supposition that superfoetation has
taken place.

1. A woman bearing a full-grown male child
had neither lochia nor milk after its birth, and
a hundred and thirty-nine days afterwards
bore a second child — a living girl, when the
milk and lochia came naturally. Eisenmann,
who had observed this case, explained the
occurrence by supposing that a double uterus
existed; but upon the woman's death some
time afterwards, no unusual structure was
found.f

* Archiv. Gen. torn. xii. p. 125. Another
similar instance is related in torn. xvii. p. 89, of the
same work.

t See Burdach's Physiol.

470

GENERATION.

2. Desgranges observed another instance in
which a woman bore two girls at the interval
of a hundred and sixty-eight days in the
same circumstances as in the above-mentioned
case.*

3. A third case is related by Fournier in
which two girls were born at the interval of
five months, there being lochia for a few days
after the birth of the first.f

4. A fourth instance is mentioned of two
children born at the interval of a hundred
and nine days.J

5. Velpeau relates that a Mad. Bigaux had
first a living child, and four and a half months,
or a hundred and forty days afterwards, a
second, also alive.§

We confess that we think these cases, if
correctly reported, go far to prove the possible
occasional occurrence of superfoetation in the
human species. On the supposition that two
children born alive at different periods remote
from one another have been conceived at the
same time, three months appears to be the
greatest extent to which the interval between
their births could reach, the first being born
prematurely at six and a half or seven months,
and the second being retained in the uterus
till the period of nine and a half or ten months ;
but this is improbable in some of the instances
before us, as both children appeared equally
complete, and no mere difference in the rate
of their growth could account for their birth at
so remote periods.

We are reduced then to the necessity of ad-
mitting the possibility, in very rare instances, of
superfoetation ; but at the same time we may
remark that the evidence regarding it is not
sufficiently precise, and we are left entirely at
a loss to explain what causes may give rise to
this variation, and in what manner the seminal
fluid may be supposed to pass through the
uterus, or the new ovum to gain an entrance
there.

§ 2. Influence exerted by parents on the

Stalities of their offspring in generation. —
ne of the most obvious and important laws
of the reproductive function is that by which
the specific distinction of animals is preserved.
Like produces like ; and for the most part an
undeviating succession of generations of simi-
lar structure and qualities prevents both the
extinction of any species and its being blended
with or lost in any other. Numerous examples
will recur to the mind of every one, of striking
family resemblance, which point out in how
many respects children frequently inherit their
qualities from their parents ; but it must be
held in remembrance that family or hereditary
resemblance is seldom if ever complete, but

* Diet, des Scien. Med. torn. liii. p. 418.

t Ibid. torn. iv. p. 181.

t Stark 's Archiv. fur die Geburtshulfe, &c. B. iv.
S. 589.

§ Traite d'Accouchements, torn. i. p. 345, where
cases are referred to by Pignot in the Bull, de !a
Facult. 4e Annee, p. 123, by Wendt, Journal des
Progres, torn. x. and Fahrenhorst, ibid. torn. viii.
p. 161.

only of that more general kind which belongs
to the species. Thus in one family we re-
cognise numerous minute differences, and in
fact it may be said that there are scarcely any
two individuals of the same or of different
family exactly alike. In respect to sex, the
most obvious difference exists : the mother
producing male and female; the son is not an
exact copy of his father, nor the daughter of
her mother, nor are they a mixture of both ;
but each of them bears certain resemblances to
one or other or to both of the parents, into
which it may be interesting to inquire, — an in-
vestigation which is to be regarded of some
practical importance in reference to the breed-
ing of cattle and other stock.

As the female parent furnishes the greater
part of the substance of the egg in all animals,
and in viviparous animals provides also the
materials which serve for the nourishment of
the young with which it is intimately con-
nected during utero-gestation, it might, a priori,
have been supposed that the offspring should
be more subject to be influenced by the qua-
lities of the mother than by those of the father ;
but no general fact of this kind is established,
and instances need not here be adduced which
shew that the offspring, whether male or fe-
male, bears nearly, if not quite, as many
points of resemblance to the father as to the
mother.

Such influence as the male parent exerts
upon the qualities of the offspring must be
transmitted and take effect at the period of
conception only, and the impression being
that of the contact of the seminal fluid with
the ovum must be momentary only. A cer-
tain part of the female parent's influence is
dependent on the original constitution of the
ovum formed in her body, while another part
of that influence may be supposed to extend
through the whole period of utero-gestation.

We shall first consider those instances of
the transmission of hereditary qualities which
appear to belong to the original constitution
of the male and female generative products,
and subsequently make some remarks on the
influence which the female has been held to
exert during the whole of pregnancy.

The general structure of the body, the sta-
ture, form, size of the bones, disposition to
the formation of muscle, deposition of fat, or
the reverse, seem to depend as frequently on
the female as on the male parent in the human
species. In some animals the male parent
more frequently determines the size and general
form of the body, as among feline animals,
dogs, horses, &c* The bantam cock is said to
cause the common hen to lay a small egg, and
the common cock causes the bantam hen to
lay a larger egg than usual.

An enumeration of all the points of struc-
ture which constitute family resemblance would
detain us too long, and is unnecessary as they
are familiar to every one. It does not appear
to be satisfactorily established that the family
resemblance is derived more from one than
from the other parent, though in one family
the influence of the one parent, and in another

GENERATION.

471

family the influence of the other parent, may
predominate.*

Nor does it appear that any general law has
been established regarding the transmission of
the nature of the constitution, temperament,
state of health, duration of life, &c.; for in the
human species at least these qualities of the
offspring seem to be inherited from either
parent or from both indiscriminately.

The complexion and colour of the offspring
has received much attention. In some animals
the colour of both parents is sometimes pre-
served, as in the piebald horse; in others a
mixture of the colours of the father and mo-
ther appears in the offspring as an interme-
diate tint. In other animals, and most fre-
quently in the human species, the colour de-
scends from one only of the parents. Thus
among white races of the human species, it
happens more frequently, when the parents are
of different complexion, that the child takes
after one or other of them than that its com-
plexion is intermediate between those of the
parents; but it does not appear as yet to be
ascertained that one parent determines the
colour more frequently than the other. The
offspring from the union of people of dark
and white races of the human species usually
has a complexion which is a mixture of or is
intermediate between the complexions of the
two parents, as in the Mulatto and other degrees
of colouring; but it is alleged that in these
instances the colour of the father usually pre-
dominates over that of the mother. Thus a
dark father produces with a white mother a
darker child than a white father with a dark
mother. Among animals there are infinite
varieties in this respect. White colour is
said to be more readily transmitted than others.
In some animals, however, colour is trans-
mitted with great regularity : thus it has been
found that as many as two hundred and five
of the product of two hundred and sixteen
pairs of horses of similar colour inherited the
colours of their parents.

The degree of fruitfulness in bearing off-
spring, or the opposite, sterility, the qualities of
the voice, peculiarities in the degree of deli-
cacy of the external senses, as long or short-
sightedness, musical ear, &c., the physical
powers of the body as illustrated in the speed
or strength of horses, and peculiarities of the
digestive functions of the nature of idiosyn-
crasies, are other familiar examples of bodily
qualities usually transmitted in hereditary de-
scent from one or other parent to the offspring.

Lastly, the qualities of the mind are, perhaps
as much as the bodily configuration and powers,
subject to influence from the hereditary in-
fluence of parents upon their offspring. The
powers of observation, memory, judgment,
imagination, the fancy, and all that belongs to
what is usually called genius, the emotions,

* Dr. Walker, in a short essay lately printed for
private distribution, has attempted to shew that the
upper and back part of the head usually resembles
the mother, the face from the eyes downwards
most frequently the father.

passions, desires, and appetites, as inborn
mental qualities of the offspring, are all liable
to be influenced in the act of generation by
the parents.*

The hereditary predisposition of man and ani-
mals to particular diseases also illustrates in a
striking manner the general law now under con-
sideration, and from its importance in reference
to life assurance has attracted considerable at-
tention.

Almost all the forms of mental derangement
are more or less directly hereditary, one of the
parents or some near relation being affected.
Of bodily diseases, pulmonary complaints,
diseases of the heart, scrofula, rickets, worms,
gout, rheumatism, hemorrhoids, hypochondri-
asis, scirrhus, apoplexy, cataract, amaurosis,
hernia, urinary calculi, may be mentioned as
examples of diseases more or less directly
transmitted as predispositions from parent to
offspring. The goitral and cretinous affections
combined with deficient intellect are striking
examples of the effect of hereditary influence
combined with that of the situation in which
the cretins live. The union of goitrous per-
sons in particular districts leads to the pro-
duction of cretins, while the union of a cretin
with a healthy person tends to the improve-
ment of the offspring, or its gradual return to
the healthy state.

The predisposition to disease may be trans-
mitted to the offspring from either parent, and
from the one as often as from the other, but
much more certainly when both the parents
have been affected with the disease.

We may also mention, in connection with
this subject, the transmission to the offspring
of various marks and deformities in the struc-
ture of the parents or their relations. The
cretinism already mentioned is one of these,
and there are numerous other cerebral de-
formities which are so transmitted, as congeni-
tal malformations, such as the acephalous and
anencephalous states, spinabifida,cyclopia, &c.
which run remarkably in particular families.
In many instances the hereditary cause of
these deformities has been distinctly traced to
one or other of the parents. Naevus, moles,
growths of hair in unusual places, hare-lip,
deficient or supernumerary toes or fingers,
have all been traced to hereditary influence,
and probably as often to the one parent or his
family as to the other. Malformations of the
heart, congenital hernia, and indeed most other
malformations, are capable of being traced to a
similar origin.

Were further illustration of this general law
requisite, it would be found in the resem-
blance of mules or hybrids produced by the
union of two distinct races, varieties, or
species of animals, which productions also
afford an excellent opportunity of observing

* In endeavouring to estimate the degree of
original resemblance of offspring to parent mentally
as well as bodily, but especially the former, great
caution is necessary not to overlook that resem-
blance between them which depends on education,
similar habits, pursuits, mode of life, and conti-
nual intercom se.

472

GENERATION.

and comparing the amount of hereditary in-
fluence exerted by one or other of the parents.
The hybrid usually combines to a certain ex-
tent the qualities of its father and mother, as
in the familiar example of the common mule
between the male ass and the mare, or in the
product of the tiger and the lion, the dog and
wolf, the pheasant and black grouse, the gold
and common pheasant, and others. In some
mules the qualities of the father predominate,
in others those of the mother ; but so far as
we are aware, the isolated facts regarding this
point have not yet been brought under any
general law.

It has been asserted that acquired qualities,
whether mental or bodily, of the parents are
capable of being transmitted to their offspring.
Thus the superiority of a civilized over a bar-
barous nation is said to depend, not solely on
the influence of an advanced state of educa-
tion upon each new comer, but also on the
greater natural powers of the children, derived
from their parents at the moment of their
production, or, in other words, the greater
capability of the children to receive the higher
mental acquirements and more refined ideas
belonging to the civilized condition of society.

Farther, it is asserted that dogs and cats
which have accidentally lost their tails have
brought forth young ones with a similar de-
formity. Blumenbach affirms that a man who
had lost his little finger had children with the
same defect. A wound of the iris and a defor-
mity of the finger occasioned by whitlow are
said to have been transmitted. The well-trained
pointer of this country produces a puppy
much more capable of being trained than the
dogs of the original breed. The retriever spaniel
and the shepherd's colly are said to do the
same. Well-broken horses produce docile
foals, and lastly, the young of foxes living in
hunting countries are naturally much more
circumspect than those living in countries
where they are not exposed to the danger of
pursuit.

We look upon all these alleged facts with
distrust. Many of them are coincidences;
others, we suspect, are false. It is obviously
insufficient for our purpose to ascertain the
qualities of the one generation which is born.
We must also know to what circumstances
the parent may have owed its peculiarity. We
feel convinced that education more than any
other circumstance has influenced the superior
powers of the animals above alluded to, and
there is no proof that the parent did not
possess the same capabilities or natural powers
as the offspring.

There are, on the other hand, innumerable
instances which shew that acquired alterations
of structure are not transmitted. How many
men are there who have lost limbs and yet
have produced children in no respect maimed.
A quadruped without the fore-legs has borne
entire young. A bitch in which the spleen
had been extirpated had young possessing that
organ. Men with only one testicle have sons
with the usual number ; and lastly, the people
of nations, the males of which have been cir-

cumcised during hundreds of years, have chil-
dren with foreskins not a bit shorter than those
of nations in which no such practice exists.

The breeding of domestic animals of dif-
ferent kinds, suited respectively to the various
useful purposes for which they are employed,
is a subject connected with the present question
of high practical importance ; but unfortu-
nately, though some practical men have well
understood the proper method to be pursued,
it is to be regretted that the facts have never
been reduced to general rules, and that the
theory has been almost entirely neglected.

It is generally admitted as a fact proven
that in the ox, horse, and other domestic
animals the purer or less mixed the breed is,
there is the greater probability of its trans-
mitting to the offspring the qualities which it
possesses, whether these be good or bad.
Economical purposes have made the male in
general the most important, simply because
he serves for a considerable number of females.
The consequence of this has been that more
attention has been paid to the blood or purity
of race of the stallion, bull, ram, and boar
than to that of their females ; and hence it may
be the case that these males more frequently
transmit their qualities to the offspring than do
the inferior females with which they are often
made to breed. But this circumstance can
scarcely be adduced as a proof that the male,
caeteris paribus, influences the offspring more
than the female.

Bad as well as good qualities may be trans-
mitted, and, therefore, it is obvious that in
endeavouring to improve any stock by engraft-
ing a good quality, the breeder must choose a
male which, besides the requisite good quality,
is free from those defects of the female which
it is desirable to sink. He must also select a
male in the family of which the desired quality
has been long resident. He cannot engraft
the quality all at once, but must endeavour to
introduce it by frequent crossing.

In the horse, for example, the strength of
bone and weight of muscle suitable for slow
draught, the light frame and prodigious swift-
ness of the race-horse, and the intermediate or
rather combined qualities of the carriage-horse,
hack, or hunter, are all capable of being pro-
duced by proper attention to purity or mixture
of breeds. The pace, speed, action, temper,
courage, colour or quality of hair, and almost
all other qualities may be increased, dimi-
nished, or altered by a judicious admixture of
different races. So also the immense weight
of beef and fat of the large ox, the flavour
of the flesh, the abundance or richness of the
milk of the cow, are subject to modification in
every different breeding.

The economical breeder, then, while he has
settled in his mind the object which he wishes
to accomplish in any of his stocks, must hold
in recollection that it is only by the combi-
nation and continued succession of good qua-
lities that he can ensure a permanent improve-
ment. He must not expect to be able to
effect this by crossing the breed of an impure
blooded or worn-out female with a male of

GENERATION.

473

superior qualities. Bad qualities may become
as fixed as good ones, and a judicious selection
of the good ones (as adapted for his purpose)
ought to be his first and principal object.*

A belief exists \vith some, founded, it is
said, both on common observation and scien-
tific research, that frequent breeding in the
same family, or what is commonly called
breeding in and in, has the effect of deterior-
ating a race. There appears, however, much
reason to believe that the opinion just now
stated is founded in error. In a state of nature
it not unfrequently happens, among those ani-
mals especially which do not pair, that the
strongest males take precedence of the weaker,
and naturally select the finest females (as
occurs in the deer); but in a state of domes-
ticity this cannot always be the case, and
inferior animals coming together give rise to
inferior offspring; but, if in the farm-yard
sufficient care be taken in the selection of the
breeding males and females, it does not appear
that near relationship has any effect in dete-
riorating the race, nor in impeding the trans-
mission of good qualities which may be found
in males and females of the same family.

The belief now alluded to has been held in
relation to the human species also, and it is
affirmed that both the bodily and mental qua-
lities of the offspring suffer gradual and pro-
gressive injury from the continued mixture of
successive generations of the same family or a
small number of families. Hence we find
that the marriage of cousins-german, which
is according to law in this country, is repro-
bated as prejudicial by some; and various
royal families and aristocratic families are re-
ferred to as examples of the bad effect of
the restriction of conjugal union to a narrow
circle.

It must be remembered, however, that the
mutual selection of the parents is not quite the
same in the human species as among the lower
animals; and in the examples just referred to
we feel even inclined to doubt whether, when
due allowance is made for the nature of their
education, it will be found that kings or
princes have become worse or less talented
in modern than in ancient times, or whether
among that class there is, on an average, a
greater proportion of stupid men than in other
ranks of society.

The regularity of feature and beauty of the
Persian race has been greatly improved by
their choice of the most beautiful Circassian
and Georgian wives ; and there are many
examples of particular families in this country
in which regular and handsome features and a
well-knit and fully developed form of body
are hereditary. We shall not pursue the at-
tempt, however, which some have made to
apply the principles of cattle-breeding to the
human species ; for however desirable and
necessary an improvement of the breed may
appear to some Utopian philanthropists, we

* We refer the reader to the Farmer's Series of
the Library of Useful Knowledge. Vols. Horse
and Cattle.
VOL. II.

fear that the mind, with all its peculiar tastes,
prejudices, and passions, has too much to do
with the greater number of matrimonial al-
liances to allow physiological considerations
much jurisdiction.

From the different facts now touched upon,
it is obvious that the original type of the parents
modifies that of their offspring; while, in gene-
ral, varieties accidentally acquired do not pass
in hereditary descent, unless they are of such a
nature as to constitute a permanently distinct
race or variety.

In the mixture of different races of the human
species and of distinct species of animals we
recognise a constant tendency in succeeding
generations to return to the original type or pure
breed ; an effect which seems to proceed natu-
rally from the general law already announced,
that the purer the breed of either of the parents,
or in other words, the more nearly it approaches
the original type or unmixed race, the more
readily will its qualities descend to the off-
spring. When the mixed offspring of the black
and white races of men unites with either the
black or the white, the offspring in successive
generations becomes more and more nearly
allied to the pure breed with which the cross is
made, and at last wholly identified with it.
We must look upon this general law of the
tendency of all mixed varieties to return to the
original type, together with the circumstance that
hybrids rarely breed as means adopted by na-
ture for the preservation of distinct species.

The transmission of hereditary resemblance,
either as regards the general structure of the
body or peculiarities, is not, however, invari-
able, nor always immediate from parents to off-
spring. Thus parents with certain deformities
may produce all their children naturally formed
and healthy ; or some of them only (in one
case the males, in a second the females, in a
third some of both sexes) may inherit the ab-
normal peculiarity, while the rest of the chil-
dren are healthy. But these healthy children,
from some disposition of their constitution, may
transmit to their descendants either in the first
or in a subsequent generation the defect which
existed in their parents. The varieties in this re-
spect in the human species are almost infinite.
Thus, in one family all the children resemble one
parent in a striking manner ; in another the
male children take after the father chiefly, the
females after the mother ; and in a third the
converse holds, the peculiarities of the father
descending principally to daughters, those of
the mother to sons, — an arrangement of family
resemblance which is the most commonly pre-
valent according to M. Girou, who endeavours
to shew that family resemblance frequently
passes in an alternating manner from grand-
parent to grandchild. Thus, the grandchild
resembles the grandparent of the same sex, so
that a boy whose father is like his (the father's)
mother resembles most the grandfather, as in
the following plan.

1st Generation. Grandf. Grandm.
2d ditto | Father

3d ditto Son Daughter

If it should be proved that a first or earlier

•2 r

Grandf. Granilm .
Mother |

Son Daugh.

474

GENERATION.

impregnation influences the product of a sub-
sequent one, in breeding any particular stock
of animals, it would appear of importance that
the female should always breed with well qua-
lified males ; and farther, that the genealogy of
both parents for one step, if not more, back-
wards, ought to enter as an item into the cal-
culation of the probable qualifications of the
offspring.

Much information is, however, still wanting
on this subject, which, as it involves the most
obscure parts of the generative process, we can
hardly expect ever to be able to fathom. It
cannot but be a matter of wonder and extreme
interest to inquire how, in the unformed germi-
nal spot of the egg of the female at the moment
when it receives the vital fecundating influence
of the male semen, the disposition to the forma-
tion of those minute modifications of structure
and function which constitute hereditary re-
semblances is capable of being retained and
transmitted to the future offspring.

The celebrated Darwin and some other fan-
ciful speculators on physiological subjects held
an opinion* that the transitory state of the
minds of the father or mother at the instant of
conception has a marked influence on the men-
tal and physical qualities of the offspring.
Thus it has been alleged that children begotten
after debauchery or drunkenness are liable to
idiocy or weakness both of mind and body ;
that when the amorous propensities are too
much excited, the offspring runs the risk of
erring in the same way ; and in short, that ac-
cording to the predominance of one or other
sentiment, propensity, or frame of mind, the
offspring may be a genius or a dolt, a sentimen-
tal swain or an unfeeling brute, a thief, a rob-
ber, a murderer, &c. Leaving to others the
proof or disproof of the alleged facts upon which
the above-mentioned belief is founded, we
would take the liberty of expressing our doubts
as to whether at the particular time alluded to
by these theorists any idea but one is usually
predominant. Nor shall we here dwell upon
the obvious local treatment which is applicable
upon the phrenological view of the subject;
but as few may be aware of the real importance
of that critical period in which life is conferred
upon a new being, we have thought it right to
put our married readers at least upon their
guard against unrestrained yielding to any of
the baser feelings or ideas, which do creep into
the best-regulated establishments, requesting at
the same time that they will communicate to
their partners such information as may be con-
sidered necessary for the attainment of the grand
object in view, viz. the improvement of the po-
pulation of this kingdom.

The belief now stated as regards the human
species has also been applied to animals, and
that either parent may thus influence the off-
spring. Thus it is asserted that the male race-
horse when excited by running, if not fatigued,
is in the best condition for communicating speed
to his offspring. Again, it is related that at

* More recently adopted by Mr. Combe, of Edin-
burgh, in his Work on the Constitution of Man.

the time when a stallion was about to cover a
mare, the stallion's pale colour was objected to,
whereupon the groom, knowing in the effect
of colour upon horses' imaginations, presented
before the stallion a mare of a pleasing colour,
which had the desired effect of determining a
dark colour in the offspring. This is said to
have been repeated with success in the same
horse more than once. As a similar case, the
influence acting through the mother, it is related
that a cow belonging to a farmer of Angus, in
Scotland, had been grazing in company with
an horned ox of a black and white colour for
some time before it came into heat. The bull
which impregnated the cow had no horns, and
differed totally from the ox in colour, as did
also the cow itself; and yet, wonderful to
ralate, the next calf was black and white, and
had horns.

These stories lead us to the consideration of a
host of extraordinary relations, from which the
general conclusion has been drawn, by no very
logical process of induction, that the imagina-
tion of the female parent is capable of exerting
a powerful influence on the structure and qua-
lities of the offspring either at the moment of
conception or during part of the period of utero-
gestation.

The effects of the mother's imagination upon
the child are so various that we cannot hope to
be able to reduce them to any general or com-
plete enumeration. Those which have attracted
the greatest share of attention are of the nature
of blemishes, spots, wounds, deficient and re-
dundant parts, in short, all unnatural or so-
called monstrous formations of the child.
The alleged causes of these unnatural for-
mations include all those circumstances which
powerfully excite the moral faculties, the
fancy, desires, or passions of the mother ;
sudden surprise, fear, anger, horror or disgust
on her being a witness of any unusual or
frightful event or object, or the opposite pas-
sions of joy, pleasure, admiration, &c. as
well as strong longings, desires, and appe-
tites, whether satisfied or not. The influence
of the mother's imagination upon the child
is not confined in its effects to bodily disfigu-
ration or change, however, for those who carry
their belief its whole length hold that the mind
of the child may also be similarly modified.
Thus it is stated that the ambition, courage, and
military skill of Napoleon Bonaparte had their
foundation in the circumstance that the empe-
ror's mother followed her husband in his cam-
paigns, and was subjected to all the dangers of
a military life ; while, on the other hand, the
murder of David Rizzio in the presence of
Queen Mary was the death-blow to the personal
courage of King James, and occasioned that
strong dislike of edged weapons for which that
crafty and pedantic monarch was said to be re-
markable.

We can readily believe that all sudden
or violent changes in the functions of the mo-
ther, derangements of the general circulation,
nervous affections, and other circumstances
which tend to disturb the uterine function,
must cause or be liable to occasion injury to

GENERATION.

475

the foetus or its coverings during pregnancy.
So also we can understand that any violent
affection of the mind of a pregnant woman, in
so far as it tends to derange the bodily func-
tions, may produce some effect on the nutrition
of the child.

Some contagious diseases pass from the mo-
ther to the child in utero. Syphilis and small-
pox may be mentioned as those the effects of
which have been most frequently observed.*
Typhous fever, on the other hand, is said rarely
to affect the child. We know also that severe
affections of the mother may cause the death of
the child, and its premature expulsion or abor-
tion. According to Hausmann, the effect of
variations of the external atmosphere is visible in
the unusual number of blind colts and hydro-
cephalic pigs which are born after a wet sum-
mer. Malformations of the foetus of birds have
been artificially produced by external injuries
and altered position of the eggs during incuba-
tion, f The transmission to the child of the
effects of chemical poisons taken by the mother
has also been observed ; but in all the foregoing
the effect of the injury has been more or less
general ; and there is no sufficient reason to
conclude from them that a particular impres-
sion on the mind of the mother is capable of
producing physical injury, or a particular de-
formity in one or other of the organs of the
fcetus.

A vague notion is entertained by some that a
certain influence is exerted by the hen or other
bird on the eggs that they incubate, by which
the qualities of the progeny are modified. But
we must observe that hereditary resemblances
are preserved in artificial incubation without
the hen ; and although we are disposed to ad-
mit that the female bird incubates its eggs with
an instinctive care and perfection that art can
rarely imitate, we are exceedingly sceptical as
to the possibility of any other secret influence
from the oviparous mother to its offspring
once the eggs have left the body ; and the
attempt to support the theory of imagination by
this opinion is an explanation of the obscurum
per obscurius.

Were it possible to separate the better authen-
ticated from the more fanciful relations of the
effects of the mother's imagination, or to select
those instances only in which the impression
on the mind of the mother had been carefully
noted before the birth of the child, we might
expect in some degree to be able to free this
question from the falsity and prejudice which
obscures it. But such a separation we believe
to be impossible, and we have therefore re-
solved to enumerate shortly some of the more
remarkable cases taken at random, J from which

* In reference to this, it is an interesting circum-
stance that the child is affected with small-pox
some time after the mother, as if the contagion had
taken the same time to operate as it does in passing
between two persons.

t As in Geoffory St. Hilaire's experiments, which
the author has more than once repeated with a si-
milar result.

i From Burdach's Physiologic, B. ii. and from a
talented Refutation of the Doctrine of the Imagina-

we think the reader will best be able to judge
what value or faith is to be attached to the facts
now under consideration.

In a certain number of these cases we are
told that an injury of an organ in the mother
causes a similar injury in a corresponding part
of the child's body; as in the following ex-
amples.

1 . A cow killed by the blow of a hatchet is
found pregnant of a fcetus with a bruise on the
same place of the forehead.

2. The same was the case with the young one
of a hind that had been shot.

3. A pregnant cat which had had its tail
trodden on bore five young, in four of which
the tail was similarly wounded.

4. A woman bitten on the pudenda by a dog
bore a boy having a wound of the glans penis.
This boy suffered from epilepsy, and when the
fits came on during sleep was frequently heard
to call aloud, " the dog bites me ! " There
are other similar cases on record.

5. A pregnant woman walking with a friend
has her head knocked violently against her
friend's, and shortly afterwards bears twins,
which are joined together by the foreheads.

6. A gentlewoman who was cut for rupture
in the groin during her pregnancy, bears a boy
having a large scar in the same region, which
he bore for thirty years afterwards.

The injuries of others operating on the ima-
gination of the mother may affect the structure
of the child : thus —

7. A woman who was suddenly alarmed by
seeing her husband come home with one side
of his face swollen and distorted by a blow,
bears a child (a girl) with a purple swelling
covering the forehead, nose, &c. of the same
side.

8. A child is born with hare-lip, which was
caused by the mother's frequently seeing a
child with the same deformity during her preg-
nancy.

9. A mother seeing a criminal broke upon
the wheel, bears an idiot child, of which the
bones are similarly broken.

10. A woman seeing a person in an epileptic
fit brings forth a child which is subject to
epilepsy.

11. A lady in London, who is frightened by
a beggar presenting the stump of an arm to her,
bears a child wanting a hand.

12. A child is born with its head pierced,
in consequence of its mother having seen a
man run through the body with a sword.

13. A woman is forced to be present at the
opening of a calf by the butcher. She after-
wards bears a child with all the bowels hang-
ing out of the abdomen. This woman was at
the time of the accident aware that something
was going wrong in the womb.

14. A similar misfortune happened to the
child of another woman, who was imprudent
enough to witness the disembowelling of a pig
during her pregnancy.

tionists, by Dr. Blundell, of London. Professor
Burdacb, we may remark, is inclined to adopt the
belief.

476

GENERATION.

The mere description of an event may affect
the child, as in the following curious case.

15. A woman who had listened with con-
siderable interest to a description of the ope-
ration of circumcision bears a child with the
foreskin split up and turned back !

16. A woman who sees another affected with
prolapsus uteri bears a child affected with the
same disease.

The examples of the effect of sudden fright,
disgust, anger, joy, &c. are very numerous.

1 7. A lady absent from home is alarmed by
seeing a great fire in the direction of and near
her own house ; and some months afterwards
bears a female child having the distinct mark
of a flame on her forehead.

18. A pregnant woman frighted by her hus-
band pursuing her with a drawn sword, bears
a child with a large wound in the forehead.

19. A man who had personated a devil
(or satyr according to other authorities) goes to
bed in his assumed dress, and his wife, being
then pregnant, afterwards bears a child having
horns, cloven feet, &c.

20. A mother frighted by the firing of a gun
has a child wounded as by a gun-shot.

21. A pregnant woman falls into a violent
passion at not being able to obtain a particular
piece of meat at a butcher's shop ; she bleeds
at the nose, and wiping the blood from her lip,
afterwards bears a child wanting the lip.

22. A woman two months before being
brought to bed is alarmed by hearing a report
that a neighbour had murdered his wife by a
wound on the breast, and bears a child with a
similar wound.

23. A child is born with the hair of one
side black, that of the other white: competent
judges declared at the time that both sides
would have been white, but for the circum-
stance that the mother had carried a heavy sack
of coals during her pregnancy.

24. A woman frighted by the sudden ap-
pearance of a negro brings forth a child with
various black marks.

25. A mother is suddenly frighted by a
lizard jumping into her breast, and afterwards
gives birth to a child having a fleshy excre-
scence exactly like a lizard growing from the
breast, to which it adhered by the head or
neck.

26. A child has a face exactly like a frog's,
from the mother having held a frog in her hand
about the time of conception.

27. The remarkable resemblance of a wo-
man to an ape was fully accounted for by her
mother having been much pleased with one of
these animals when with child of her.

The effect of the attentive contemplation of
pictures, statues, &c. by pregnant women is
worthy of notice.

28. A child is born covered with hairs in
consequence of the mother having been in the
habit of beholding a picture of St. John the
Baptist.

29. A woman gives birth to a child covered
with hair and having the claws of a bear, from
her constantly beholding the images and pic-
tures of bears hung up every where in the

dwelling of the Ursini family, to which she
belonged. It is not stated by the Author of
Waverley, whether any thing of the kind ever
happened in the Bradvvardine family.

30. A woman contemplating, too earnestly
as it appears, a picture of St. Pius, has after-
wards a child bearing a striking resemblance to
an old man.

31. The tyrant Dionysius was aware of the
effect of pictures ; for he hung a beautiful
picture in his wife's chamber, in order to im-
prove his children's looks.

32. Two girls (twins) were born with their
bodies joined together, their mother having
during her pregnancy been in the habit of at-
tentively contemplating two sacred images
similarly placed.

33. A child is born with its skin all mottled
in colour from the mother having made a visit
to St. Winifred's Well, and seeing the red peb-
bles there.

34. Another child was marked on the face,
in consequence of the mother having worn
black patches.

The longings and depraved appetites to
which pregnant women are liable are occa-
sionally the causes of marks and deformities
in their children.

35. There are a great many instances in
which the longing of the mother after straw-
berries, grapes, cherries, peaches, and other
fruits has caused the growth of tumours in the
children exactly resembling in each the fruit
that was wished for,

36. A woman who had longed for a lobster
brings forth a child much resembling one of
these animals.

37. Another woman had a female child, the
head of which was like a shell-fish (a bivalve,
which opened and shut as a mouth), which
proceeded from the mother's having had a strong
desire for mussels at one time of her preg-
nancy.

38. A pregnant woman longs, or has a great
desire to bite the shoulder of a baker who
happens to pass. The husband, wishing to
humour this extraordinary fancy, hires the baker
to submit to be bitten. The mother makes
two bites, but of such a kind that the baker
will not submit to more; and some time after-
wards she is brought to bed of three children,
one dead and two living.

39. A case of spina bifida near the sacrum
is explained by the mother's having wished for
fritters, and not obtaining them, having ap-
plied her hand (we know not with what object)
to a corresponding place in her own body.

The impression on the fancy of the mother
may be made before conception has taken
place: thus—

40 A woman, whose children had pre-
viously been healthy, six weeks before con-
ception is suddenly frighted by a beggar who
presents a stumped arm and a wooden leg, and
threatens to embrace her: the next child had
only one stump leg and two stump arms.

The impression on the fancy may extend to
the product of several successive conceptions.

41. A young woman frighted in her first

GENERATION.

477

pregnancy by the sight of a child with hare-lip,
bears a child with a complete deformity of the
same kind : her second child had merely a
deep slit, and her third no more than a mark
in the same place.

We do not wish to argue against this hy-
pothesis from its prima facie absurdity merely;
but we think it will be generally admitted that
the greater number of the foregoing cases are
ridiculous and incredible; inasmuch as simple
malformations of structure well known to ana-
tomists have been regarded as the represen-
tations of animals and other objects to which
they bear a very distant if any resemblance, —
cases, in short, in which it is apparent that the
imagination of the bye-standers has been more
active than that of the mother.

We shall at once admit that we ought not to
reject immediately an explanation of the me-
chanism of a vital function on account of its
obscurity merely; but we assert that the gene-
ral phenomena of the vital functions are capa-
ble of being observed and reduced to fixed
and general laws, which is certainly by no
means the case with the effects of imagination,
which are as various and contradictory as they
are absurd and ridiculous. The anatomical
connection of the maternal uterus and child is
so well known that we may with safety affirm
that no such communication exists as would
be necessary for the transmission of an im-
pression from the body of the mother to any
particular organ of the foetus, and much less
any means of conveying mental impressions
only. The longings which are said to be so
liable to cause injuries of the child seem to
act in the same manner whether the appetite
is satisfied or not, &c.

But moral reasons are much stronger against
the belief. It is obvious that in much the
larger proportion of the cases related, the co-
incidence of the mental impression on the
mother with the injury done to the child is a
post-partum observation and discovery. The
mother and her friends, or the father, if such a
deformity shall belong to his side of the house,
are desirous of finding an explanation of the
blemish which shall not be a stigma upon
them ; and in other instances it is to be feared
that the idle and talkative women who attend
upon child-beds, and even more scientific male
accoucheurs, have encouraged the mother's
belief in the effect of some alleged previous
impression (selected from thousands) on her
imagination, in order to hide undue violence
employed during the delivery, or perhaps with
a less culpable desire to quiet the fears of the
mother while in the dangerous puerperal state.
There is no doubt that there are innumerable
instances in which the imagination and all the
moral and intellectual powers of women have
been highly excited during pregnancy without
their children having suffered in any respects ;
and there are not wanting instances of chil-
dren being born with all kinds of deformity
that have been attributed to the effect of
imagination, without their being aware of any
unusual impression having been made on their
minds.

Again, it may be remarked that the stage of
the period of pregnancy at which the injury of
the child may take place is by no means de-
fined, and that there is no correspondence
between the time or advancement of the foetus
and the nature of the injury. Some injuries
are said to have occurred or to have had their
foundation laid at the very moment of con-
ception, and even occasionally before that time,
while others are inflicted only a few weeks be-
fore birth.

The monstrous appearances or malformations
which constitute by far the greater part of the
injuries attributed to the mother's imagination,
are now no longer regarded as lusus naturae
merely, or " sports of nature's fancy," as they
used to be called ; but the times at which
many of them must have occurred are known
with some degree of certainty, and these times
by no means correspond with the periods at
which the imagination is said to have been
affected. Besides this, nearly the whole of
congenital malformations have been accurately
anatomised, and their structure is reduced to
general laws as regular and determinate in
each individual form as the more usual or so-
called natural structure. See MONSTROSITY.

In this question, as in others of a like kind,
reference has been made to scriptural autho-
rity, in the history, viz. of Jacob's placing the
peeled black and willow rods before the ewes
which went to drink and afterwards conceived.
But any one who pays the slightest attention
to the whole of this relation will at once be
convinced that the sacred writer, in describing
the proceeding of Jacob, exhibits merely that
patriarch's belief in the efficacy of such means;
for in a subsequent part of the chapter Jacob
is undeceived by the angel, who appears to him
in a dream and informs him of the real" cause
of the multiplication of the speckled lambs,
&c. viz. the circumstance that the ring-straked,
speckled, and spotted males had leaped upon
the females, and that the progeny therefore
merely inherited their colour from their fathers.
We now leave this unsatisfactory subject,
upon which we have perhaps dwelt longer than
it deserves. We have introduced the foregoing
remarks partly in accordance with custom, and
also with a view to shew how little connection
exists between the facts of our subject and the
vague fancies to which allusion has been made.
In doing so we are aware that we are liable to
the accusation, on the one hand, of having
treated with too much levity facts and ob-
servations upon which some are disposed im-
plicitly to rely, and, on the other, of trifling
with science in noticing even such vain fancies
as belong to pregnant women and their atten-
dant nurses.

We conclude by adopting and expressing
the opinion of Dr. Blundell, " that it is con-
trary to experience, reason, and anatomy to
believe that the strong attention of the mother's
mind to a determinate object or event can
cause a determinate or a specific impression
upon the body of her child without any force
or violence from without; and that it is equally
improbable that, when the imagination is ope-

478

GENERATION.

rating, the application of the mother's hand to
any part of her own body will cause a dis-
figuration or specific impression on a corres-
ponding part of the body of the child."

§ 3. Number of children ; and relative
proportion of the male and female sexes.

The simpler animals are, generally speaking,
more fruitful than the complicated ones. As
examples of great fecundity, may be mentioned
some of the Entozoa and Mollusca, which pro-
duce hundreds of thousands of ova ; among
Crustacea and Insects some produce many
thousand young. The Perch and Cyprinus
genus among fishes produce some hundreds of
thousands, and the common Cod, it is said,
some millions of ova. Most of the Batrachia
produce at least some hundreds. But in the
warm-blooded Vertebrata, the necessity of in-
cubation or utero-gestation puts a limit to the
number of young ; and there are also compara-
tively few in the Blenny, Skate, Shark, Land
Salamander, or such animals as are ovo-vivi-
parous.

In the human female, the number of chil-
dren altogether produced is limited, first, by
the number of Graafian vesicles in the ovaries,
which usually amounts to from twelve to fif-
teen in each ovary ; and second, by the length
of the time during which a woman bears chil-
dren, (the greatest extent of which is usually
twenty-five years, that is, from the age of fifteen
to forty, or twenty to forty-five,) the length of
this period again depending upon the rapidity
with which the births succeed one another, and
the number of children produced at each.

Women most frequently bear every twenty
months, but some have children at shorter in-
tervals, as of fifteen or even twelve months.
This often depends upon the circumstance
that in some lactation prevents conception;
in others it does not.

The number of the eggs of birds for one in-
cubation varies from two to sixteen. The num-
ber of the young of Mammalia produced in
one utero-gestation varies from one to fifteen,
and occasionally more.

Woman usually bears a single child. The
proportion of twin-births to those of single
children is estimated by Burdach as one to
seventy or eighty : the proportion of triplet
births one to six or seven thousand ; quadru-
plets, one to twenty or fifty thousand. Occa-
sionally five children come at one birth, and
there are instances on record of six or even
seven children being born at once.

The causes of this greater or less fecundity
are not known : they are in all probability
various; being not of an accidental nature,
but connected with the constitution of one
or other of the parents, most frequently per-
haps of the mother.

A healthy woman bearing during the whole
time, and with the common duration of inter-
val, may have in all from twelve to sixteen chil-
dren ; but some have as many as eighteen or
twenty ; and when there are twins, &c. con-
siderably more, as in the following remarkable
instances. First, eighteen children at six births.
Second, forty-four children in all, thirty in the

first marriage, and fourteen in the second ; and
in a still more extraordinary case, fifty-three
children in all in one marriage, eighteen times
single births, five times twins, four times tri-
plets, once six, and once seven.*

Men have been known to beget seventy or
eighty children in two or more marriages, but
the tendency of polygamy is generally believed
to be to diminish rather than to increase the
number of the whole progeny.

According to Marc, not more than two or
three children are born from two thousand pros-
titutes in the course of a year, — a circumstance
depending in part on their want of liability to
conception, and in part on frequent abortion.

The proportion of children born in each mar-
riage varies much in different countries. The
following statement of the average number is
taken from Burdach : Germany, 6 — 8 ; Eng-
land, 5 — 7 ; France, 4 — 5 ; Spain and Italy,
2— 3.f

In reference to the average proportion of male
and female births, it appears from very exten-
sive data that in this and most other countries
the number of males usually exceeds that of
females ; in this country in the proportion of
four or five in a hundred.

The circumstances which influence the pre-
ponderance of male births are not known. The
accompanying table shews how very constant
it is in different countries.

Table of the proportional number of males
and females born in different countries ; the
females being taken as 100.

Great Britain ............ 104.75

Sweden .... ............. 104.72

Wurtemburg ........ .. 105.69

Westphalia and Rhine ____ 105.86

Bohemia ................ 105.38

Netherlands .............. 106.44

Saxony and Silesia ........ 106.05

Austria .................. 106.10

Sicily ................... 106.18

Brandenburg ............ 106.27

Mecklenburg ............ 10707

Mailand ................ 107.61

Russia .................. 108.91

Jews in Prussia .......... 112.

- in Breslau .......... 114.

- in Leghorn .......... 120.

Christians in Leghorn ...... 104.

It has been found, on the other hand, that the
first children of a marriage consist of a greater
number of females and fewer males, in the pro-
portion, according to Burdach, of fifty-three
male births to a hundred females. A similar
preponderance of females is said to exist among
illegitimate children ; but the difference is

* See Foamier, Diet, des Scien. Mcd. torn iv.

t According to Burdach, one marriage out of
fifty is unfruitful ; there is one birth on an average
for every twenty-five of the population of a place ;
and taking the whole population of the world at six
hundred and thirty-three millions, about fifty-one
children are born every second !

GENERATION.

479

much less, not amounting to more than four or
six in one hundred.*

Malformations are said to occur more fre-
quently among illegitimate than legitimate chil-
dren ; and malformed children are more fre-
quently of the female sex. This, together with
the circumstance that illegitimate children are
oftenest first born, may in some degree account
for the greater number of females among them.

The data upon which it has been attempted
to found an explanation of the cause of the
formation of a male or female offspring are very
slender indeed ; nor are we likely ever to ob-
tain knowledge which shall enable us to form a
satisfactory theory regarding the cause of the
determination of the sex. Some men beget
always male children, others always females, in
more than one marriage. The same seems
sometimes to depend on the mother. In other
marriages children of one sex are born for a
time, and subsequently those of the other ; or
the male and female children may alternate,
&c. &c. without our being able to point out any
circumstance which has given rise to the pro-
duction of one or other sex.

Accordingly many vague opinions have been
entertained regarding this subject, as for exam-
ple the following :

1 . That the wishes or ideas of the parents at
the time of conceptions may influence the sex
of the offspring.

2. The nature of the food of the parents, par-
ticularly of the mother during pregnancy.

3. The use of various medicines : hence the
numerous charms and recipes for begetting
children of either sex.

4. The quantity of oxygen absorbed during
development.

5. The manner in which the spermatic artery
is given off from the aorta, and

6. The older and equally groundless notion
that male children come from the right testicle
or ovary, and females from the left; upon
which hypothesis was founded the celebrated
advice of Hippocrates : " Ubi femellam gene-
rare volet (pater) coeat, ac dextram testem obli-
get, quantum id tolerare poterit, sed si ma-
rem generare appetat, sinister testis obligandus
erit."

A belief has long prevailed that the greater
the strength of either of the parents in propor-
tion to the other, the more of its own sex will
be generated. M. Girou de Buzaraignes has
paid considerable attention to the influence of
age, strength, mode of life, 8cc. of the parents
on the sex of the offspring, and has made a
series of experiments on the domestic animals,
from which, should they be confirmed, some
important results may be expected.

According to M. Girou ,f male fathers among
the domestic animals which are either too old
or too young, produce with mature and healthy
females more female than male offspring ; while
female parents that are too old or too young in
proportion to the males bear most males. This

France. Prussia. Hamburg.

Boyt. Boys. Boys. Girls-
* Illegitimate Children ... 104- 102- 94-, lftft

Legitimate ditto 106- 106- 105- 1 1UU

t Sur la Generation.

would appear to be the case in the human
species also from the observations of Hofacker
at Tubingen, and of Saddler on the English
peerage : the children of a husband consider-
ably younger than his wife being nearly in the
proportion of ninety sons to a hundred daugh-
ters ; while those of the husband considerably
older than the mother are in the proportion of
a hundred and fifty or a hundred and sixty sons
to a hundred daughters ; the intermediate ages
being found to give a proportionate scale.

Burdach states that those women who are
most fruitful bear many more boys than girls,
as in the following examples : —

Boys. Girls.

1st woman bore 26 6

2nd ditto, in first marriage .... 27 3

in second ditto 14 0

3rd ditto 38 15

According to Girou, female domestic animals
bear more females when well nourished and
left in repose than when much worked and on
spare diet; and it has been alleged that the
sexes of plants are influenced by their nourish-
ment or soil in which they grow ; dioecious
plants having seeds which propagate more
males in dry ground exposed to the sun, more
females in moist, well manured, and shady
ground ; monoecious plants bearing more of
the staminiferous or pistilliferous flowers in cor-
responding circumstances.

The explanation of the cause of this variation
of the sex as well as of the original sexual dif-
ference, it has already been remarked, is beyond
the reach of investigation. Very interesting
observations have, however, brought to light
the different steps of the process by which the
generative organs of either sex are gradually
formed during the development of the foetus;
and a series of facts has thus been established
of great interest and importance as tending to
elucidate the nature of those numerous remark-
able malformations of the reproductive organs
generally comprehended under the term Her-
maphrodism. We refer the reader to the article
upon this subject, and to that of OVUM, for a
history of the process now alluded to, and
shall not do more than merely mention in this
place some of the more important results which
have been obtained.

1st. It appears thatin the earliest stages of foetal
life, the sexes (or what may become afterwards
either male or female, that is, all the young) are
perfectly alike in structure.

2nd. That there exists in all a common ma-
trix or rudimentary organ or set of organs,
which at a later period is converted by deve-
lopment into the male or female organs.

3rd. That the early type of the sexual organs
is to be regarded as common and single, rather
than double, as some have considered it.

In conclusion, we may remark that we must
confess ourselves equally unable to fathom the
nature of the original bias or determination
given by the parents, in consequence of which
a male or a female child is produced, and to
ascertain the manner in which any other here-
ditary influence, quality, or conformation is
transmitted from the parent to its offspring.
At the same time it appears not improbable

480

GLAND.

that the nature of the sex may in some degree
be modified by circumstances affecting the
female at an early period of utero-gestation.
In reference to this subject we ought not to
omit the mention of a fact which is well esta-
blished, viz. that when the cow bears two calves,
one of which is a male, the other, exteriorly re-
sembling the female, has its reproductive organs
internally imperfectly formed, being of that
kind of hermaphrodite formation usually called
the Free Martin.*

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mals, Philos.Trans. 1797 ; Transl. in Reil's Archiv.
Bd. 3d. Ludwig, De nisu formativo, Lips. 1801.
Vicq d'Axyr, Anat. et phys. de 1'ceuf, in CEuvres,
t. iv. Pulley, On the proximate cause of impreg-
nation, Lond. 1801. Often,- Zeugung, Hamb. u.
Wurzb. 1805. Prevost et Dumas, Nouv. theorie de
generation, in Annales des Sciences Naturelles,
1825. The various systems of Physiology, but
especially Treviranus, Burdach, vol. i., and Hal-
ler's Elementa.

( Allen Thomson.)

* See John Hunter's well known paper on the
Free Martin in his Animal QSconomy, new ed. by
Owen, 1838.

GLAND, Gr. aty ; Lat. Glandula; Fr.
Glande; Germ. Druse.

An organ whose office is to separate from the
blood a peculiar substance, almost invariably
fluid ; constantly provided with an excretory
duct ; formed of a process of the mucous mem-
brane or of the skin, disposed either in the form
of a sac or of a ramified canal ; which sac or
canal in all cases is closed by a blind extremity ;
and which, although amply supplied with blood,
is never directly continuous with the bloodves-
sels.* It is absolutely necessary to give this
definite explanation of the meaning which is
attached to the -word gland in the present article,
inasmuch as there is no term in anatomy that
has been more vaguely, and as it appears to me
more incorrectly employed.

It is not necessary to point out the absurdity
of applying this word to certain parts of the
brain, or to the masses of fat contained in the
joints, which were called by the older anato-
mists glands ; in these instances the fallacy is
immediately apparent; but there are other
errors which, although less striking, are, I con-
ceive, no less injurious in their effects. Thus
in the glandular system many continental au-
thorities include not only the liver, kidneys,
salivary glands, and other organs, which are
universally acknowledged to belong to this
class ; but likewise the lymphatic glands, the
thyroid, the thymus, the spleen, the supra-,
renal capsules, and the ovaries.f It is con-

* The only real exception to this law is the testicle
of fishes, in which no excretory duct seems to exist.

t Bichat, after condemning the application of
the term to the thyroid, the pineal gland, the
lymphatic glands, &c. states, " we ought only to
call those glands, which pour out by one or several
ducts, a fluid which these bodies separate from the
blood they receive by their vessels." Anat. Gen.
torn. ii. p. 598.

Meckel, on the contrary, objects to the opinion
that an excretory duct is essential to a gland. Ac-
cording to his definition the glandular system com-
prises, 1. the muco\is glands ; 2. the sebaceous
glands ; 3. the liver, the salivary glands, the pan-
creas, the lachrymal glands, the tonsils, testes, the
ovaries, the prostate, Cowper's glands, the kidneys ;
4. the lymphatic glands, the thyroid, the mammary
glands, thymus, spleen, supra-renal capsules.
Man. d'Anat. torn. i. p. 511.

It is surprising that so admirable a physiologist
as Meckel should adopt this opinion.

Professor Miiller has also a classification, which
seems to me objectionable ; for he has admitted
among the glands the spleen, thyroid, lymphatic
glands, &c. It must not, however, be supposed
from this arrangement that this profound anatomist
considers these particular bodies as real glands.
His classification is as follows. (Handbuch der
Physiol. des Menschen, Coblenz, 1834, p. 418.)

A. Ganglia sanguineo - vasculosa , the
spleen in the digestive organs — the su-
pra-renal capsules in the genital and
uro-poietic viscera — the thymus and
thyroid in the respiratory apparatus—
glandula choroidalis in the eye — the
placenta in the foetus.

B. G. lymphatico-vasculosa , the lym-
phatic and mesenteric glands.

Liver, salivary glands, testis, &c.

GLAND.

481

tended by these writers that the last named
bodies elaborate from the blood certain fluids,
and that as far as the real function of a gland is
concerned, it matters not whether the secreted
fluid escapes by a proper excretory duct, or is
taken up by the lymphatic vessels; it is, in-
deed, supposed by liaase that these bodies,
like the true glands, possess excretory ducts,
but this opinion has received little support.

This method of viewing the subject appears
to be very injudicious ; because it is based on
the assumption that certain organs secrete fluids
from the blood, but of which secretion we have
no evidence ; and further, because organs are
classed together, between which there is no
similarity either of structure or of function.

In establishing a well-founded distinction
between parts which, in their general form and
outward appearance, bear a resemblance to
each other, it is proper to seek for some lead-
ing and obvious character, concerning which
there can be no dispute. In applying this rule
to the present case, we shall find that the spe-
cial distinction of a true gland, as contrasted
with those organs with which it has been assi-
milated, is the possession of an excretory canal
or duct ; and taking this as the essential cha-
racteristic, there is no difficulty in perceiving
that the glandular system in the human body
ought to be restricted to the following parts : —

Mucous glands, comprising, a, simple mu-
cous glands or follicles, dispersed over the
whole extent of the various mucous surfaces,
«ither insulated or collected together, as the
glandulae Peyeri seu aggregatae. 6, Compound
mucous glands, (g. agglutinata?,) formed of the
preceding, collected into masses, and slightly
modified in their structure, comprising the
molar, labial, palatine, and buccal glands, the
lachrymal caruncle, tonsils, Cowper's glands,
prostate, and seminal vesicles, c, Sebaceous
glands, consisting of those of the skin, the
ceruminous glands, the Meibomian glands, d,
Conglomerate glands, (g, conglomeratse ;)
these, which are the most complex of the glan-
dular organs, consisting of the salivary glands
and pancreas, the mammary glands, the testicle,
the kidney, and the liver.
. These glands may be classed according to
their functions in the economy as follows : —

I. For lubrication and protection ; a. mu-
cous glands in all parts of the body ; b. seba-
ceous glands ; c. lachrymal gland ; d. lachry-
mal caruncle.

II. Connected with digestion; a. salivary
gland ; b. pancreas ; c. liver.

III. Connected with generation; a. testis ;
b. prostate ; c. seminal vesicles ; d. Cowper's
glands ; e. mammary gland.

IV. For excretion ; a. kidney ; b. liver.

By extending the principle that all glands are in
reality nothing but processes of the mucous mem-
brane ending in cul-de-sac, the lungs have, by
some writers, been included amongst the glandular
organs, the trachea, it is said, performing the office
of an excretory duct. It is certain, as we shall
subsequently show, that the lungs present, both in
their formation and functions, a close approxima-
tion to the true glands.

VOL. II.

The particular description of the above
organs and the modifications of the general
glandular structure they present, will be found
in the articles KIDNEY, LACHRYMAL APPARA-
TUS, MAMMA, &c.

Situation, — The principal glands are placed
in the head and abdomen ; in the extremities,
with the exception of those of the skin, they
are totally absent. In general they are pro-
tected from external injury by being lodged
deeply in the cavities of the body ; but to this
rule there are several important exceptions, as
the mammae, testes, parotid glands, &c.

Organization. — In the whole range of Ana-
tomy, whether Human or Comparative, there
are probably no organs which, on account of
the complexity of their structure, the number
and variety of forms which they present, and
the importance of their functions in the animal
kingdom, are more interesting than the glands,
or the structure of which, until within a very
recent period, was more imperfectly understood.
Even at the present time the prevailing ideas
respecting the essential characters of the glan-
dular organization are in general so vague and
indefinite, and but too often positively errone-
ous, that I feel myself called upon to enter
more fully into the investigation of this subject,
than would otherwise be necessary. Much of
this uncertainty has arisen from the fact that,
whilst the views of the immortal Malpighi,
founded as they are on truly philosophic
grounds, have never attracted that investigation
to which they are so justly entitled, the theore-
tical opinions of Ruysch, being received with
all the eclat inspired by his unrivalled skill in
vascular injections, have been generally adopted.
It is true that, on many minor points, Malpighi
was in error; and that the vagueness of his
descriptions, and his infelicitous comparison of
the ultimate divisions of the glands with clus-
ters of grapes or acini,* greatly assisted in pre-
venting his opinions being generally admitted
or even comprehended. But tho'se distin-
guished anatomists who have, by their recent
inquiries, at length decided the long-disputed
theories of Malpighi and Ruysch, have proved
that in all essential points the conclusions of
the former great authority are founded in truth.

Minute structure. — The investigation into
the structure of the glands, when conducted in
accordance with the enlightened principles of
philosophical anatomy, shows that the laws
which regulate their formation are simple and
definite ; and that, although Nature has dis-
played here, as in all her other works, immense
fertility in modifying the forms and characters
of the several glands, so as to render them effi-
cient to the performance of their varied offices,
yet in no single instance is there a departure
from that structure, which constitutes the type
of the whole glandular system. The unifbr-

* This term, so much employed in descriptions
of the glands, yet so indefinite in its acceptation,
has caused such confusion and misconception, that
it is most desirable to abolish it from the nomen-
clature of Anatomy. In the descriptive part of the
present article, I shall therefore scrupulously avoid
employing this expression.

2 K

482

GLAND.

mity which, with the aid of Comparative Ana-
tomy, has been so satisfactorily demonstrated
in the development of the nervous and osseous
systems, is equally evinced in the glands ; for
whatever diversities may be presented in their
form and appearances — whatever varieties may
be remarked in the internal disposition of their
component parts, as in contrasting a simple
follicle with a conglomerate gland, or the tubu-
lar biliferous organs of insects with the appa-
rently solid liver of the Mammalia; whether, in
short, they appear solid, cellular, or tubular,
every glandular organ is nothing else than a
modification of a simple closed sac. This im-
portant truth is distinctly announced by Meckel
in the following passage. " The most simple
mucous glands, which are only simple sacs,
present the type of the glandular formation. If
we picture to ourselves this sac as being pro-
longed and ramified, and interlacing its branches
between those of the bloodvessels, we shall at
length arrive at the most compound gland,
without there ever being a direct communica-
tion between the bloodvessels and the excretory
ducts."* We have here briefly but clearly ex-
pressed the great principle, in obedience to
which the various glands are developed ; but
that which Meckel only figuratively expressed,
has since been realized in all its bearings and
intricate details, by the extensive and laborious
researches of several distinguished anatomists,
and especially by Professor Miiller of Berlin.

As it would be in vain to attempt to demon-
strate the essential characters of the glandular
formation, and to prove the uniformity which
pervades the whole system, by selecting, as has
been generally done, the most intricate organs ;
I propose, in the first place, to describe the
most simple form of gland, and, seizing this as
a clue, to trace its gradual development through-
out the whole series of glandular organs, so as
to convey a general, but, it is hoped, compre-
hensive account of this interesting branch of
anatomy.

With this object in view, the simple follicles
of the skin and mucous membrane may be ad-
vantageously selected ; because by tracing the
successive development of these bodies, the
gradual transformation of a simple sac into a
tube, a ramified canal, and even a conglome-
rate gland, may be very distinctly demonstrated.
In fishes, whose aquatic mode of life renders
an abundant defensive secretion necessary, the
cutaneous follicles are more developed than in
other animals, and constitute tubes or canals,
which being carefully examined are found to
end in crecal extremities. A similar formation
is seen in the bulbus glandulosus of most birds,
where the mucous crypts are prolonged into
short tubuli (Jig. 209) ; whilst in the Ostrich
(Struthio camelus) the follicles present an ap-
pearance of cells. ( Fig. 209, &). In some
Amphibia, Salamandru maculuta for example,
the glands of the external integument being
very much developed, it is seen that each of

* Man. d'An. i. p. 515. Beclard has a similar
comparison : " it is true that a gland, like a folli-
cle, consists of a canal closed at the extremity."
Anat. Gen. p. 424.

Fig. 209.

a. Conglomerate folli-
cular gland, Struthio rhea ;
c. same, Meleagris ; d.
same, Anser $* the upper
drawing shows the cylin-
drical follicles in a young
falcon.

Fig. 210.

those bodies is com-
posed of a small flask-
shaped pouch of the
skin, which at one ex-
tremity becoming en-
larged into a base,
there terminates in a
blind sac ; whilst at the
other end being con-
tracted, it opens by a
short neck on the ex-
ternal surface. (See
fig. 210.) A micro-
scopical view of the
ccecal canals in the
simpler glands is ap-
pended . (See/%. 2 1 1 .)

Fig.ZU.

Flask-shaped cutaneous The simple sacs and
follicle or gland magni- tubes just described are
Jied — lU.f very often collected toge-

ther, giving rise to aggregate or compound folli-
cles, the arrangement and degree of complexity
of which are very various. In some instances
these sacs unite so as to form a gland with a single
orifice or excretory duct, of which the Meibo-
mian glands of the eye-lids are an example ; or
again, the aggregate follicles may themselves be
joined together with various degrees of compli-
cation, in the form of a cluster, from which
several excretory ducts proceed, as in the cu-
runcula lachrymalis, the labial, buccal, and
other mucous glands of the mouth, the tonsils,
&c. In all these instances there is nothing but
an evolution of the original sac, so that in the
same manner as this is formed from the mucous
membrane or skin, are the tubes and canals
prolonged from the third pouch, by which con-
trivance the surface subservient to secretion is,
within a given space, greatly increased. The
conversion of a sac or tube into a granular mass
is also in this manner rendered very apparent;
and thus it is easy to understand how a rami-
fied canal may produce the apparently solid

* Home, Lect. on Comp. An. ii. tab. 46.
t Berres.

GLAND.

433

granules (the so much talked of acini) of the
liver and other conglomerate glands.

Such, then, are the more simple forms of the
glandular organs ; and if we proceed to those
which are more complex, no difficulty is expe-
rienced in proving, by the aid of comparative
and developmental anatomy, that the structure,
although it becomes more and more developed,
is in character essentially the same. The
inquiries of the anatomist in this respect are
greatly facilitated by the existence of an univer-
sal law connected with the process of organiza-
tion, in accordance with which it happens that,
whenever any particular gland first appears in
the animal series, it presents invariably the
simplest form of the glandular structure, al-
though this same gland may subsequently
attain in the higher classes the most intricate
formation. It is for this reason the salivary
glands are so simple when they first appear in
birds, the pancreas in fishes, and the liver in
insects.

Ample confirmation of this gradual transition
from simple to compound, which is in fact
only another instance of the great laws which
regulate the formation of the whole animal
creation, is afforded by following any of the
more intricate glands through the several stages
of their development. Thus, if the pancreas
be examined in its rudimentary state, it will be
perceived that, like the mucous follicle, it is
composed either of a fluid sac or of a tube more
or less complicated. In the class Cephalopoda,
the individuals of which are so remarkable by
the complexity of their internal organization,
the pancreas consists either of a simple sac
opening into the intestine near the gizzard, (see
Jig. 219, p, fg. 220,/, vol. i. p. 533), or of a
spiral canal, (fg. 221, /, p. 535,) the secerning
surface being increased by a number of laminae.
In most fishes there are numerous fluid appen-
dages placed near the pyloric extremity of the
stomach, (appendices pyloric&,) which are with
propriety regarded as constituting a rudimen-
tary pancreas, (fg. 212,) and which, in the in-

Fig. 212,

Fig. 213.

Fig. 214.

stance of the Sturgeon and Swordfish are ag-
gregated into a glandular mass.* (Seefg. 46,
vol. i. p. 115.)

The liver is certainly the most intricate struc-
ture of all the glandular organs when examined
in the higher animals ; and yet, if we descend
to the lower classes, which present, as it were,
a natural analysis of the various parts of the
animal machine, the texture becomes suffici-
ently simple. One of the most simple forms
of this organ is probably furnished in the lum-
bricus terrestris ; at least I have seen in that
animal, in a few instances, a beautiful appear-
ance of coecal tubuli composing the yellowish
substance which coats the intestine, and which
is thought by some authorities to constitute the
liver. In many insects, Crustacea and other
Articulata, the biliferous organs consist of fluid
sacs proceeding from the stomach or intestine,
and often assuming the appearance of tubes,
but always closed at their distal extremities.
In some instances these tubuli are very simple,
(see fig. 37, d, vol. i. p. Ill,) but in other
cases they are more complicated, and present a
ramified arrangement; and in this manner the
structure evidently approaches that of the most
compound or conglomerate glands. The liver
of the Lobster presents an excellent illustration
of the crecal tubuli which constitute the secre-
ting structure, of so many species of glands.
By cutting out a por-

tion of this organ, and
slightly unravelling the
tubes by moving the
section in water, the
canals ending in cul-
de-sac are beautifully
seen, and if slightly
magnified, it is found
that they closely re-
semble the pyloric ap-
pendages of fishes. The

* Haller remarks that, in the Skate and Shark,
the pancreas is similar to that of higher animals.
2 K 2

484

GLAND.

adjoining figure (fig. 214) conveys a very
accurate representation of this structure as it
exists in the biliary organs of the astacus
jftuviatilis, the digital tubuli (r) being depicted
as they appear when partly unravelled.

In another of the Crustaceans, pagurm stria-
tus (fg. 215), the same kind of structure is

Fig. 215.

observed, constituting a very complex liver.
In the suuilla mantis that organ is so remark-
ably intricate that Cuvier supposed it formed
an exception when compared with the other
genera of the Crustacea, which, as we have
seen in the instances above, possess biliary
organs composed of blind tubes, by being lo-
bulated and solid like a conglomerate gland.*
It has, however, been ascertained that the
lobules are excavated in their whole extent,
and communicate by openings with the intes-
tine, which runs through their sponey mass,
so that the secreting surface is wonderfully
increased in extent.f

That the liver consists of a blind pouch,
originating from the intestinal canal and be-
coming more and more complicated, is further
shown in many of the Mollusca, in which the
excretory ducts are so large that they appear
like branches of the intestine, and thus present
a structure which is somewhat analogous to

* Lemons d'An. Comp. t. 4. p. 152. It is proper
to observe that Cuvier, in thus alluding to a solid
conglomerate gland, appears to have fallen into
the common error respecting; the nature of the
minute granules, or acini as they are called.

t Mullcr de Gland. Secernent. Struct, p. 70,
$5.

those curious ccecal diverticula observed in
certain of the Annelida, well seen in the
ap/trodita aculeata, and which are by some
anatomists regarded as forming a rudimentary
liver.

The evolution of the liver in the embryo
affords an additional proof of the disposition
of the secreting surface or membrane in the
interior of the compound glands. In one of
the Gasteropoda. ( Limnaus stagnalis) the liver
is first produced as a pellucid sac from the
intestine. In an amphibious animal (buj'o
cainpanisonus) a prolongation in the form of
a sac is seen in the intestinal membrane, which
constitutes the first appearance of the liver; as
the development proceeds, the hepatic duct is
formed, and becoming ramified, produces at
length a number of branching tubes, which
present a granulated form. The evolution of
the liver in the green lizard (lacerta viridis)
is very similar, the organ first appearing under
the form of a hollow sac proceeding from and
communicating with the cavity of the intestine,
and subsequently having branches of ramified
tubes added.*

If from the investigation of these more simple
forms, which might be multiplied almost ad in-
fotitum, we proceed to the conglomerate glands
of Mammalia, it will be observed that, al-
though the component parts of these highly
organized bodies are so closely packed together
as to present a solid and granular appearance,
yet by a careful inspection it may be satisfac-
torily determined that the true secreting struc-
ture consists of tubuli with ccecal ends. For
this purpose the testicle may be advantageously
selected : if this organ without any previous
injection be divided, the section at first sight
seems to consist of a great number of small
roundish bodies or granules; but if, as occa-
sionally happens, the tubes are distended with
semen at the time of death, by a more cautious
examination it is immediately apparent that
these little bodies are composed of a very fine
tube coiled up or convoluted. By injecting
the tubuli seminiferi with mercury, the formation
of the little grains is rendered more evident ;
but the most successful mode of displaying
the whole internal formation of the testis is by
filling the tubuli with a coloured size injec-
tion, f

It was remarked by FerreinJ that the kid-
ney is a tubular organ, and the extensive re-
searches of Miiller as well as those of Huschke
have proved that the secreting or cortical part
is made up of an immense number of serpen-
tine tubes of an equal diameter throughout,
ending in blind sacs, and becoming continuous
with the straight canals placed in the cones of the
organ. This structure is seen \njig.2l6, where a
magnified view of the cortical ducts of Ferrein,
the secerning apparatus, and the straight excre-
tory tubes is given as the parts exist in the
scijirus. This structure offers a close resem-
blance to the tubuliform liver of some insects.

* Miiller 1. c. tab. x. fig. 13.

t Sir A. Cooper on Testicle.

f Mein. de 1'Acad. Roy. des Sc. 1749, p. 489.

GLAND.

485

(Sec the biliary organs of
Meloloutha Vnlgaris, Jig. 38,
vol. i. p. 111.)

In the liver of Mammalia
and Man, both in the embryo
and after birth, it is much
more difficult to demonstrate
the ultimate tubes with their
crecal extremities; indeed the
existence of such canals is ra-
ther deduced from the ana-
logy of the liver in the lower
animals than from actual ob-
servation. Miiller states that
the blind free extremities of
the biliary ducts are visible
on the surface of the liver
with the microscope in the
embryo of Mammalia; but
that owing to their compact
arrangement they are less dis-
tinct than in birds, so that
their internal connexions can-
not be perceived.* In a few
Mammalia, however, as the
squirrel, ( scwrus vulgar Uy) he
observed with the microscope
the blind cylindrical extremi-
ties of the biliary ducts on
the surface of the liver, pre-
senting a branching and foliaceous appearance.
(Fig. 217.) The exact mode of termination of

Fig. 217.

Fig. 216.

Fig. 218.

the biliary tubuli was still more distinctly seen
in a portion of liver considerably magnified,
taken from an embryo of the quail, ( Tetrao
coturnix,) about one inch long (fig. 218J.
From the published
account of Mr.
Kiernan's valuable
observations on the
minute structure of
the liver, it does
not appear that the
actual terminations
of the biliary tubes

in blind extremities were perceived, although
that such is their disposition is rendered very
probable from what was seen with the mi-
croscope, and especially because it was found
that much greater difficulty was experi-
enced in injecting these tubes than the
bloodvessels, on account, as it was sur-
mised, of the bile contained within them
having no exit.*

Lastly, in tracing the minute texture
of these complex glands of the Mam-
malia, it is necessary to call the attention
of the reader to a circumstance which of
all others has been the most fertile source
of error, so much so indeed as to have
misled the great majority of anatomists.
It is this : in many glands small rounded
or berry-shaped corpuscles seem to be
appended to the commencement of the
secreting tubes, so that a deceptive ap-
pearance is produced, as if cells or little
bags were placed between the terminal
bloodvessels and the small excretory
ducts. This appearance of cells or even
of solid rounded corpuscles is depen-
dent on two causes : in some glands the se-
creting canals are so coiled up that, as is seen
in the human testis, when a section is made in
the uninjected state an apparently granular tex-
ture is presented, (fig. 219;) but a second
influential circumstance is that in many in-
stances each of the secreting tubes swells out
at its ccecal end into a slightly enlarged cul-
de-sac ( pedunculated tubes}, so that when they
are viewed in an aggregate form, the semblance
of roundish-shaped granules is seen, (Jig.
220.) As these and all other varieties which
are presented in the glandular formation are

* L. c. p. 80, § 21, 22.

* I»hii. Trans. 1833, p. 741.

486

GLAND.

Fig. 219. considered in the

several articles
on the individual
glands, it is only
necessary to state
in this place that
what are called
indifferently lo-
bules, glandular
grains, vesicles,
acini, &c. are in
every instance
composed simply
of trie secreting
canals variously disposed and arranged

It is, however, very remarkable that whilst
those glands which arise from the alimentary
canal present an immense variety in the ar-
rangement of their secreting texture, the essen-
tial glands of the genito-urinary apparatus, the
kidney and the testicle, have a most uniform
structure, consisting of serpentine tubes of the
same diameter throughout their whole extent.

The details into which I have thought it re-
quisite to enter prove that the true secreting
structure consists in every gland of nothing
else than a vascular membrane, on the surface
of which the glandular fluid is poured out; and
consequently that in those complex organs, as
the liver or kidney, in which the vascular se-

Fig. 220.

Peripheral ramification of the parotid duct, with some of the vesicular terminations,
magnified = 1 10.*

creting membrane is, for the sake of conveni-
ence, disposed in the form of extensively rami-
fied tubes, it is most important to recollect that
the glandular fluid is poured not only into the
coecal extremity or commencement of each
tube, as is the commonly received opinion, but
along the whole extent of the tube. For the
establishment of this fact, certainly the most
important in the history of the glands, we are
principally indebted to Professor Miiller.

Excretory duct. — Although the essential seat
of the glandular function is now ascertained,
some difficulty exists in determining the actual
extent of the secreting surface in the various
organs; or in other words, at what precise
point the mucous canals ceasing to secrete,
become mere excretory passages .f An attempt
to decide this point is, however, necessary,
because until this time the majority of anato-

* Berres, 1. c. pt. 5, tab. ix. fig. 2.

t I allude here of course to the peculiar secre-
tions, as the bile, urine, milk, &c. and not to the
secretion of mucus, which we know is poured out
along the whole- extent of the excretory ducts.

mists have signified by the term excretory duct,
not only the canals which simply bear away
the secreted fluid, but likewise those tubes
which constitute the true secreting apparatus,
and which, it is evident, are at the same time
both secreting and excreting canals, as they not
only secrete, but likewise carry to the larger
and non-secreting ducts the fluids poured out
by their parietes.

In the simple sacculi or follicles, it is evi-
dent that the secreting structure is co-equal
with the extent of the bag itself, so that the
little orifice becomes the excretory duct; in the
tonsils, prostate, &c. there are several such
orifices or ducts. But at what point does
secretion cease in the compound glands ? Mr.
Kiernan states,* that in the liver the secreting
portion of the organ is confined to what he
calls the lobular biliary plexuses, or to those
tubes which are placed within the lobules ; so
that here the excretory apparatus is very com-
plex, consisting of the interlobular tubes, those

* Phil. Trans. 1833, p. 741.

GLAND.

487

of Glisson's capsules, and, lastly, of those
which quit the organ. The limitation thus
established, and which I have no doubt is
strictly correct, may be applied to all those
glands, such as the salivary, mammary organs,
&c., which, like the liver, possess distinct
lobules. In the kidney the true secreting
structure is probably restricted to the serpen-
tine tubes contained in the cortical texture,
(canales cortica/es, or ducts of Ferrein,) the
straight canals (tub. Belltniani) constituting
the cones, which bodies, in a minute injection
of the bloodvessels, are nearly colourless,
being merely for excretion.* The testis, with
its appendix the epididymis, presents an in-
tricate arrangement; it is probable, however,
that the principal secreting part consists of the
seminal tubes which form the lobules, and that
the vasa recta and efferentia are merely ex-
cretory in their office; in the upper part of the
epididymis a second secreting structure is met
with, constituting the coni vasculosi, whilst
the lower part containing the convolutions of
the vas deferens is of the excretory character.

It is proper to observe that the process of
secretion is incessantly going on ; but with the
exceptions of the mucous, sebaceous, and a
few other glands, the fluids produced are
destined to be poured out only at stated in-
tervals; it is, therefore, evident that some con-
trivance is required, by which the several secre-
tions may be retained, till the moment arrives
when it is necessary they should be discharged.
The liver may be selected to illustrate this
principle : one of the most essential functions
of that organ being the decarbonization of
venous blood, its constant action is no less
indispensable, indeed considering the whole
animal series, is even more indispensable than
that of the lungs themselves ; and yet the pro-
duct of that action, the bile, is only designed
to be poured into the duodenum during the
process of digestion. In order to obviate the
irritation of the bowels that would result from
the incessant discharge of the bile, and at the
same time to economise that fluid, the gall-
bladder is provided, which, receiving the se-
creted fluid in the intervals of digestion, fulfils
all the conditions required. The absence of
the gall-bladder in several classes of animals
can scarcely be admitted as being incompatible
with this explanation; for the majority of
these instances of deficiency occur in non-
ruminant vegetable feeders, in several genera
of the Pachydermata and Rodentia for example,
in which it is evident that as the process of
digestion must occupy a considerable period,
a prolonged flow of bile is requisite, and a
special reservoir is less necessary ; in addition to

which it is known that in some of these cases,
as in the horse and elephant, the principal
trunk of the biliary ducts is very large, and
may in some degree supply the place of a gall-
bladder.*

The urinary bladder is a provision rather
of convenience than of necessity, enabling the
animals that possess it to retain the urine as it
flows from the ureters, until a considerable
accumulation takes place. These are the only
instances in the human body of a distinct re-
servoir being provided ;f but every gland, by
retaining its secretion in the excretory ducts,
has a power of emitting the fluid, under certain
circumstances, in larger quantities than usual,
as in the case of the salivary and lachrymal
glands; a similar accumulation must take place
in the seminal tubes and prostatic ducts, and
especially in the lactiferous tubes and their
terminal sinuses. In animals the examples of
distinct reservoirs are too numerous to be here
enumerated.

Structure of the secreting canals and excre-
tory ducts. — It is now certain that all these
tubes are composed essentially of a prolonga-
tion of the mucous membrane. The former,
according to Miiller, consist only of a single
coat, but it must be presumed that they pos-
sess in addition a tunic, having, independently
of elasticity, a power of contraction by which
their contents are propelled often in a direction
opposed to gravity, and in obedience to the
application of a mechanical stimulus to the
surface on which the ducts terminate. In the
excretory ducts the internal membrane is sur-
rounded by a fibrous structure, which is very
apparent in some of the larger canals, and
probably exists in all. The fibres of this coat
are of a greyish white or brownish colour, and
are often so fine and compact that they are
distinguished with great difficulty. The real
character of this structure is not known ; in
appearance there is little or no resemblance to
proper muscle; the action, however, of the
excretory canal seems to require a contractile
power; and Meckel states that he has dis-
tinctly perceived circular fibres in the vas
deferens, which tube is said to be distinctly
muscular in the bull.

Bloodvessels. — If it be recollected that the
arteries carry to the glands the materials of
their various secretions, and if the large quan-
tity of fluid formed by those viscera be called
to mind, we shall not be surprised to find that
with a few exceptions, such as the lungs and
the brain, there are no organs so abundantly
supplied with arterial blood. This supply is
in proportion to the activity of secretion, rather
than to the size of the gland ; thus the kidneys,

* It is stated by Muller that all his researches
induce him to conclude that the serpentine tubuli
of the cortical part constitute the true secreting
texture; an opinion which is corroborated by a
very curious preparation contained in the museum
of the Webb -Street School of Anatomy, in which
a sac has been formed on the outer surface of the
kidney, containing a number of small calculi, and
having no connexion whatever either with the
straight tubes or with the iniundibula.

• Carus, Traite Elena. d'An. Comp. ii. p. 269.
It may be proper to state that the Otter, according
to Daubenton, possesses the above dilatation of the
duct in conjunction with a gall-bladder.

t Some anatomists conceive that the vesiculae
seminales are merely receptacles of the semen j
but this opinion has been to a great extent aban-
doned in England since the observations of Hunter.
See the works of Hunter, edit, by Palmer, vol. iv.
p. 20. Note, p. 26.

488

GLAND.

furnishing about four pints of urine daily,
receive, in proportion to their bulk, more blood
than the pancreas, where the secerning process
is less active. That this is the principle which
regulates the supply of blood is also evidenced
in the vessels of the mammae, which receive a
more ample supply of blood during lactation
than at other periods.

The sangmferous vessels, like the secreting
canals, present many varieties in their dis-
position in the several glands, the varieties of
form in each class being, however, definite in
their character, and doubtless having a re-
ference to the different kinds of fluids which
are required to be separated from the circu-
lating blood. Those organs which are pro-
vided with a distinct envelope, as the testicle,
the kidney, and liver, usually possess but one
artery, which enters at the same fissure as the
excretory canal ; other glands, presenting a more
distinctly lobulated texture and having no
proper capsule, the tonsil, pancreas, and mam-
ma for instance, receive an indefinite number
of arteries, which enter irregularly on all parts
of the surface ; lastly, in the mostsimple form,
as the mucous crypts, the secreting vessels con-
stitute a delicate plexus on the surface of the
little bag.

In all those instances where the gland is
large enough to receive one or more arterial
trunks, it is found that the vessel having
entered begins to divide into smaller branches,
which penetrate between the masses of the
gland, and these becoming smaller and smaller
at length furnish an intricate plexus, the
branches of which, as in the case of the simple
bag or follicle, ramify on the surface of the
blind secreting canals.

It is only necessary to observe with respect
to the veins, that when compared with their
arteries, they are smaller than elsewhere ; and
also that in common with the veins of the
splanchnic cavities, they are devoid of valves,
so that in the kidney, liver, &c. they may be
beautifully displayed by the aid of a suc-
cessful injection, even to their ultimate rami-
fications.

Arrangement of the minute bloodvessels. —
In considering the intimate texture of the
glands, it is essential to state the manner in
which the last divisions of the sanguiferous
vessels are disposed. By the aid of minute
injection these vessels may be demonstrated,
though with difficulty, as far as their termina-
tion ; and they may also be observed in a few
instances during life and whilst carrying on the
circulation.

An opinion to which we shall subsequently
recur has been entertained by many anatomists,
that the little arteries are either directly con-
tinuous with the excretory ducts, or, as we
should rather call them, the secreting canals, or,
at all events, that some kind of direct commu-
nication exists between the terminal arteries
and the secreting canals. The most cautious
and apparently successful researches, however,
do not corroborate this opinion, but, on the
contrary, show that no direct communication
of any kind exists. In the lungs, which organs

are formed and developed in exact accordance
with the glandular structure, the ultimate divi-
sions of the pulmonary artery, after freely
ramifying over the surface of the air-cells, are
known to terminate by direct continuity in the
radicles of the pulmonary veins. Now, that
which is demonstrated in the lungs equally
applies in the case of the glands. In the
simple lacunae of the mucous membrane the
arteries are disposed over the surface of the
pouch, but they end in the returning veins
without opening on the secreting surface.
Miiller states that on examining with a suffi-
cient power the larva of the triton pulmtris,
he observed streams of blood, traversed by
single globules, running between the elongated
secreting canals of the liver, and, further, that
the last arteries pass immediately by a reticu-
late anastomosis into the small hepatic veins.
This disposition is seen in the adjoining figure,
which represents the circuit of the blood in the
larva of the triton fifteen lines in length'.

Fig. 221.

a, veua cava j b, vena poitanun , ct minute cur-
rents of blood in the gall-bladder.

GLAND.

489

Miiller expressly says, that in no organ are the
J'ree extremities of the bloodvessels seen, but
that the arteries always j)ass by u reticulate
anastomosis into the veins; that the blood cir-
culates between the secreting canals of the
liver, and at length on their surface, so as, as it
were, to soak their coats with blood, but it does
not pass into the canals themselves; or, in
other words, that the sanguiferous vessels are
not continuous with the biliary tubes.*

The important investigations of Kiernan
respecting the minute anatomy of the liver,
have shewn that the vena portae having divided
so as to constitute an intricate plexus in each
lobule of the organ, and having ramified on
the secreting canals, terminates in the hepatic
vein.f In the section on the development
further evidence is furnished in corroboration
of these observations.

In all the^e instances, then, it is proved that
there is no continuity between the arteries and
the secreting tubes; and as the smallest secreting
canals are always considerably larger than the
smallest bloodvessels, the proportion varying
in different glands, it may be assumed that in
the whole glandular system, the arteries, having
divided to a great degree of minuteness, and
having ramified freely on the surface of the
secreting canals, terminate directly in the re-
turning veins.

Although in former times such a disposition
of the bloodvessels as that now described
would have been regarded as incompatible
with the process of secretion, yet since the
interesting researches of Dutrochet on Endos-
mose and Exosmose,^ there is no difficulty in
understanding that fluids may readily pass
from the interior of the arteries into the se-
creting canals without there being any direct
communication between these two orders of
tubes. Not only may this passage take place,
but even it is rendered probable by the experi-
ments of Magendie§ that the bibulous matter
constituting the glandular texture, and present-
ing, as we have found, so many varieties in its
physical characters, may separate fluids, varying,
according to the gland employed, from the
diversified substances mechanically mixed toge-
ther and suspended in the blood.

Lymphatic vessels. — Notwithstanding these
are readily traced in the larger glands, their
disposition, and especially their origin, are not
known ; a connexion, however, has been rather
generally admitted in certain glands between

» De Gland. Struct., p. 74, § 12. Phys. des
Menschen, 1 Band, p. 441.

t Phil. Tran. 1833, p. 745. Mr. Kiernan infers
that the hepatic artery terminates, not as is usually
supposed in the vena hepatica, but in the vena
portae. Miiller, however, thinks it is not probable
that this is the true disposition, because the prepa-
rations of Leiberkuhn show that the capillary
branches of the venae hepaticae can be as readily
injected from the hepatic artery as from the hepatic
vein. Notwithstanding these objections, analogy
would induce us to suppose that Mr. Kiernan is
correct in his supposition.

J Nouv. Keener, sur 1'Endos. et 1'Exosmose,
1828.

$ Lect. on the Physical Conditions of the Tissues,
Lancet, 1834-35. '

their ducts and the lymphatics. In one instance
Cruikshank tilled the absorbents of the mamma
from the lactiferous ducts ; and both Walter
and Kiernan contend that the absorbents of the
liver may be injected from the biliary ducts.
Miiller, on the contrary, denies this commu-
nication, and states that the lymphatics are
much larger than the smallest secreting canals.
He also contends as to the results of injections,
that the arguments drawn from them have no
greater weight than all others derived from the
fortuitous passage by rupture of fluids from
one into a different order of vessels.

Nerves. — In proportion to their size the
glands, like the other organs of the vegetative
functions, receive very small nerves, which are,
with some few exceptions, derived from the
system of the great sympathetic. The nervous
fibrils surround and accompany the branches
of the arteries, till, in the interior of the gland,
they become so minute that it appears impossi-
ble to detect their exact termination. Miiller
states that they never separate from the blood-
vessels, and, consequently, that they do not
supply the proper glandular substance. But in
such a case as this the evidence afforded by
microscopical inspection alone should be re-
ceived with great reserve, especially when it is
recollected that in opposition to the doubtful
information thus acquired must be placed the
unquestioned fact that the mind is capable of
influencing the contraction of the secreting and
excreting tubes, as is instanced in the flow of
the saliva, of the tears, and of the semen under
certain mental impulses. But perhaps a still
more striking illustration of the control of the
nervous system is afforded by the discharge of
several glandular fluids resulting from impres-
sions acting on comparatively remote but
associated surfaces — the pouring forth of the
saliva for example, in consequence of the con-
tact of various substances with the tongue ; of
the bile and pancreatic juice from the applica-
tion of food to the surface of the duodenum ;
of the semen from the stimulation of the glans
penis. In all these and similar instances it
must be presumed from analogy that the effect
of the physical impression is conveyed through
the only known media of conduction, the
nerves.* The iacts here adduced respecting
the influence of the nerves merely relate to the
contraction of the secreting and excreting
canals ; how far the nervous energy is essential
to the process of glandular secretion itself be-
longs to another division of the subject. (See
SECRETION.)

Interstitial cellular tissue. — A considerable
portion of every gland is made up of the con-
necting cellular membrane, which, as in all other
organs, enters the interior, where it fills up all
the minute fissures and angles that intervene
between the tubes and lobules, and at length,
penetrating between the most minute of the
secreting canals, it constitutes a nidus for the
lodgement of the constituent parts.

The investing membrane is in many instances

* I have in another place entered more fully
upon this question : Obs. on the Struct, and Funct.
of the Spinal Cord, p. 136, et seq.

490

GLAND.

simply formed by the condensation of the con-
necting cellular tissue, but in the larger glands
a proper fibrous capsule is provided, which
adheres more or less intimately to the proper
glandular texture.

General conclusions respecting the minute
structure of glands.

1. That throughout the whole range of the
animal kingdom and in every species of gland
there is one uniform type, from which the
glandular formation in no instance deviates.

2. That every gland consists of a membrane
derived either from the skin or mucous mem-
brane.

3. That this membrane is disposed either in
the form of a pouch or of a tube more or less
ramified, and terminates in every instance, with-
out an exception, in a blind extremity.

4. That the secreting canals are most diversi-
fied in form, being simply sacculated, branch-
ing, pennitifid, nail-shaped, or enlarged at the
commencement, cellular, berry-shaped, serpen-
tine.

5. That granules or acini in the hypothetical
sense of writers do not in reality exist.

6. That whatever may be the variety of form
it is always subordinate to the grand principle
which the whole glandular system displays, —
namely, that the largest possible extent of
secreting surface is contained in the smallest
possible space.

7. That there is no immediate connexion or
continuity between the secreting canals and the
sanguiferous vessels.

Hypotheses respecting the minute structure
of glands. — I was desirous in the first part
of this article to convey to the reader a com-
prehensive view of the glandular structure,
unincumbered by any reference to the opinions
of anatomists on this subject; but the hy-
potheses of Malpighi and Ruysch have so
long divided the world of science, that it is
necessary to ascertain how far the doctrines
advocated by those celebrated men are in
accordance with the above-stated conclusions.
In doing this, however, much difficulty is
experienced, especially in considering the
opinions of Malpighi, inasmuch as his com-
parisons of the minute structure of the liver,
of which organ he principally treated, are very
vague and obscure, and being for the most part
unaccompanied by illustrative plates, it is
almost impossible in many of his descriptions
to detect the meaning he wishes to convey.
But, notwithstanding these obstacles, it 'is
evident, on studying his account of the liver
and kidney, that justice has not been done
to his researches; for he not only corrected
many of the then prevailing errors, but also
ascertained several important points connected
with this interesting branch of anatomy.

Malpighi compares the minute lobules of
the liver and other conglomerate glands to
a bunch of grapes, these lobules being joined
to the neighbouring lobules by intermediate
vessels. His words are, '; for as an entire
bunch of grapes is formed of small bunches
by a communion and tying together of vessels,
which small bunches are themselves formed

into a mass by appended grapes (acini); so
the whole liver is formed by lobules many
times folded, and which are themselves formed
of glandular globules."* It is thus observed
that Malpighi describes in the liver larger and
smaller lobules ; and it is to these latter that
the celebrated but vague term of acini appears
to be more particularly applied. He observes
that the lobules are of various forms in different
animals ; in fishes having the shape of a
trefoil, in the cat six-sided, &c. The inter-
lobular spaces are noticed as being distinct
in fishes, but as obscure in the more perfect
animals.

With respect to the intimate structure of
the small lobules, or acini, Malpighi conceived
that each of them consisted of a hollow vesicle,
receiving the secreted fluid from the small
arteries and conveying it into one of the roots
or branches of the hepatic duct ; or, in other
words, that the structure of the acinus was
the same as that of the simple mucous follicle.
Owing, however, to the imperfect means then,
possessed of prosecuting such inquiries, it is
certain that Malpighi did not detect the ultimate
structure; for more exact observations have
proved that the last divisions of the secreting
canals, although they constantly terminate in
ccecal extremities, do not always end in follicles,
but that they may consist of serpentine tubes,
as in the kidney, or of pennatifid canals, &c.
It also has been determined that what he
regarded as the last divisions of the ducts, or
acini, are themselves composed of smaller
canals. But his observations on the develope-
ment of the liver in the chick shew that he
was acquainted with the essential facts con-
nected with the structure of that organ, and
with the mode of its formation ; for among
other interesting remarks, he says that on the
seventh day of incubation the liver of a yellow-
ish or ashen colour presents granules of rather
an oblong form, and " as it were blind pouches,
appended to the hepatic duct."f

This hypothesis, founded as it is on so
large a body of evidence, was generally re-
ceived ; but the discovery of the art of minute
injection, which seemed to afford ocular de-
monstration of the fallacy of Malpighi's theory,
induced the majority of anatomists to adopt
the ideas rather pompously announced by
Ruysch. This celebrated anatomist, rejecting
the hypothesis of Malpighi, contended J that
he had proved, by injection, that the arteries
are directly continuous with the excretory
ducts; or that the little ducts proceed from
the minute arteries, like lesser from larger
branches ; and that each acinus consists prin-
cipally of bloodvessels, but contains also an
excretory duct.§

In considering the merits of these two hy-
potheses, it becomes apparent that Ruysch
supported his opinion by evidence of a most
insufficient character ; for in investigating the

* De Viscer. Struct, cap. iii. p. 18.
t De Format. Pulli in Ovo, p. 20.
t Opuscul. Anat. de Fabric. Gland. Opera
otnnia, t. iii.
§ Loc. cit. p. 56, fig. 2.

GLAND.

491

most complicated glands he relied solely on
his vascular injections, to the exclusion of the
evidence afforded by the much more satisfactory
researches of comparative and developmental
anatomy. If, as Professor Miiller has ob-
served, Ruysch had carefully examined his
injected organs with the microscope, he would
have found that between the most delicate
plexuses of the bloodvessels there is always
an additional substance destitute of vessels ;
although these organs, when seen by the naked
eye, appear to be stained in every direction
with the coloured injection.* But even ad-
mitting what frequently happens from a too
forcible injection, that the matter thrown into
the arteries is found in the ducts, this does
not prove that the small bloodvessels are con-
tinuous with the excretory canals ; for after
the sanguiferous vessels are filled, they easily
become ruptured, and so allow their contents
to escape into the ducts. It may further be
objected, that in all the glandular organs which
have been carefully inspected the commence-
ments of the excretory ducts are larger than
the least arteries ;f indeed, Ruysch's own
account of this imaginary continuity is very
vague, and the plates designed to illustrate
his theory, especially that of the kidney, are
any thing but satisfactory. As Ruysch did
not employ the microscope, it is impossible
he could have xeen that continuity which he
so confidently described; indeed, as Haller
remarks,! it i§ difficult, or rather as we should
say impossible, to demonstrate, with the aid
of the most powerful lens, the connexion of
the last arteries with the coats of the ducts.

Not only did Ruysch adopt a most in-
sufficient mode in prosecuting his inquiries,
but he assumed as a fact what was in reality
a mere hypothesis, that secretion can only take
place from the open mouths or orifices of the
secerning arteries. The only point, therefore,
which he discussed was, whether the passage
of the arteries into the excretory ducts takes
place gradually and insensibly, or suddenly
and by the intervention of a follicle ; for it
never occurred to the anatomists of those times,
or even to Haller and his contemporaries, that
canals closed at their end by cul-de-sac, and
without open arterial mouths, could secrete. §

* Loc. cit. p. 8, $ 4.

t Diameter of secreting canals.

Line

Parotid gland . . . 0-0099 (Weber).
Kidney .... 0-0166 (Meckel).

Ditto 0-0180 (Weber).

Testis .... 00564 (Miiller).

Ditto 0-0648 (Lamb).

Liver (in rabbits) . . 0-0140 (Muller).
Diameter of capillary bloodvessels.

Line Line

Parotid . . 0-0030 to 0-0039 (Weber).

Kidney . . 0 0044 to 0 0069 (Muller).
Testis . . . 0-0030 to 0-0035 (Weber).

Burdach Physiol. Fiinfter Band. p. 38. For
measurements in otber glands, see Muller De
Gland. Struct, p. 112 ; Valentin Handb. der En-
twickelungs-geschichte, p. 535 et seq.

J El. P~hy. t. ii. p. 378.

£ The existence of open mouths in the arteries
of the serous membranes, where they are generally

But the true opinions of Malpighi did not
refer to the exact mode of termination pos-
sessed by the arteries; nor did he imagine
that any particular machine or follicle was
interposed between the arteries and the ducts :
his observations were rather directed to the
more important circumstances relative to the
disposition, formation, and extent of the true
secreting canals.

In concluding these remarks on the hypo-
thesis of Malpighi, it is due to the character
of that illustrious cultivator of anatomical sci-
ence to state that his views are highly phi-
losophic, and in a general manner correct —
that they are supported by numerous obser-
vations made on the glands of the lower ani-
mals, as well as on the development of the
liver during incubation — and that he had thus
the sagacity to adopt the mode, which expe-
rience has shown is alone capable of resolving
this difficult question.

It would be superfluous to enter into a de-
tailed account of the opinions advanced by
later anatomists, as they are for the most part
simply modifications of the hypothesis either
of Malpighi or of Ruysch. A few general
observations will therefore suffice.

Ferrein has the merit of being the first wri-
ter who pointed out in a more distinct manner
than had been done by Malpighi, the great
importance of what are erroneously called the
excretory ducts, but which constitute, as we
have already shown, the true secerning struc-
ture. He remarks* that the cortical part of the
kidney is composed of a collection of white
cylindrical tubes, variously folded on them-
selves (canales corticales, or ducts of Ferrein,)
and he thought he had seen the same tubes in
the liver. The serpentine cortical canals have
been seen in birds by Galvani, to be filled with
cretaceous urine after the ligature of the ureter.
Although the researches of Ferrein are very
important, yet they want that support from
comparative anatomy, by which means alone
they could have been made subservient to esta-
blish any general principles.

To Rolando belongs the honour of having
demonstrated the mode in which the glands
are developed from the alimentary canal. By
carefully conducted observations on the in-
cubated egg, he discovered that each of these
organs in the first instance consists of an ele-
vation or tubercle of the intestine, which sub-
sequently becomes hollowed and forms a canal
directly continuous with that of the intestine.
He also distinctly announced what has since
been demonstrated in all its details, that the
lungs are formed, like the glands, by a pushing
out of the upper end of the intestinal tube ;
and he further describes the mode in which
the bronchi and their subdivisions are deve-
loped. The error of those writers who contend

called exhalants, has never been proved; on the
contrary, on examining, with a powerful micro-
scope, the circulation of the peritoneum in rabbits,
I have repeatedly observed that the small arteries,
after ramifying in a very complicated manner,
become distinctly continuous with the little veins.
* Mem. de 1'Acad. Roy. des Sc. 1749, p. 492.

492

GLAND.

with Ruysch that the bloodvessels arid the
secreting canals are continuous with each other,
is clearly shown ; in short, Rolando was the
first modern anatomist, who, following in the
footsteps of Malpighi, pointed out the manner
in which the inquiry ought to be prosecuted,
and thus laid the foundation of those laborious
and interesting researches for which science is
principally indebted to the German anatomists,
and by which, within the last few years, the
subject of the glandular organization has been
so strikingly elucidated.*

Developjnent.—The investigations of Har-
vey, Malpighi, Rolando, Weber, Meckel, Bar,
Valentin, Rathke, Muller, and many other
anatomists, have very satisfactorily determined
the manner in which the glands are in general
developed. It is, however, necessary to pre-
mise that these observations principally relate
to -thane glandular organs which are appended
to the alimentary canal, especially the salivary
glands, the pancreas, and liver ; for as regards
the development of those glands that are
subordinate to the secretion of urine and to
generation, comprising essentially the kidney
and the testis, much uncertainty still prevails,
although it is rather generally believed that the
corpora Wolftmna, or false kidneys, are in some
way or other connected with their primary for-
mation .f

From the researches that have been made
with so much care, we learn that, although
there are many modifications of the formative
process in the different classes of the glandular
organs, there are yet certain fixed laws in
obedience to which they are produced. As the
development of the individual glands is, how-
ever, considered in the several articles on those
organs, it is only requisite to describe in this
place in a general manner, and without no-
ticing the modifications of the general rule,
the process of formation. In prosecuting this
inquiry two different objects present themselves
for examination, — the primitive substance in
which the gland is developed, and the internal
component parts, consisting essentially of the
secreting tubuli and the bloodvessels.

1. Every gland is formed from a portion of
the primary plastic and amorphous mass
(blasloderma) of which the body of the embryo
consists.

2. This mass is at first gelatinous, extremely
delicate and diaphanous ; it subsequently be-

* Journ. Comp. des Sc. Med. xvi, p. 54, p. 57.
P. t>3. The honour of discovering the mode in
which the glands appended to the alimentary pas-
sage are formed by pushings-out of that tube has
been by Burdach improperly attributed to Rathke.

t It would be inconsistent with the perfection
of the formative process to conceive that either the
kidney or the testis requires the aid of any other
glandular organ for their development ; besides
which it may be mentioned that there is no actual
connexion between the above glands and the corpora
Wolffiana. Rathke observes. " Although they
(corpora Wolffiana) are not organically connected
with the kidneys and genital organs, they appear
to be, in an early period of the life of the embryo,
the precursor or representative of the kidney."
Burdach, II. Band. p. 646.

comes thicker and less transparent. In the
beginning it is solid, and in the case of those
glands which are appended to the alimentary
canal, — that is to say, the salivary glands, the
liver, and the pancreas, (and the same laws
are observed in the formation of the lungs,*)
it appears as a projection on the mucous mem-
brane. (Fig. 222, A.)

Fig. 222.
A

A plan designed to show tJie first origin of tlie glands.

a, b, alimentary canal ; g, gland. (The letters
have the same signification in A, B, C, D.)

3. In a short time this rounded mass begins
to project on its external surface, and thus
forms a number of lobes, or, as it were, little
islands, which, by the continuation of the same
process, become more and more numerous and
smaller in size ; and thus, according to the cha-
racter of the gland examined, are at length
formed all the minute lobes of which it con-
sists. (JF/g.222, B.)

4. Simultaneously with this development of
the outer surface of the plastic mass, but quite
independently of it, a metamorphosis is going
on within, by which the internal canals, which
subsequently become the secreting tubes, are
formed. In the first instance a hollow or
cavity is noticed communicating with the tube
of the intestine, and which subsequently be-
comes the principal or excretory duct. When
it first appears it is a simple sac, (Jig. 222, C,)
but in proportion as the projections or lobes
are formed on the external surface, lateral
branches are added to the principal duct ; and
these again become more and more ramified,
till an indefinite number of tubes are formed.
(Fig. 222, D.)

* Rathke, in Burdach's Phy. II. Band. p. 580,
edit. 1837. Valentin, 1. c. p. 501 et seq.

GLAND.

493

This development of ccecal
tubuli is seen in the liver of
Limmcus stagnate in tlie em-
bryo state, (fig. 223). In
the embryo of Lacerta vi-
ridis, (fig. 224,) the rudimen-
tary liver with its blind se-
creting canals (e) are observed;
the elongated heart (a) fur-
Jig. 224.

Fig. 223.

nishing the aorta (fe) dividing into its right and
left trunks, together with the principal venous
tnink (c), are represented ; d is the intestine,
J the rudiment of the corpora Wolffiana, and
g g the rudiments of the upper and lower
extremities.

One of the most remarkable differences ob-
served in the development of the several glands
relates to the proportion between the mass of
the primary plastic substance, and the extent
and number of the contained tubes ; thus, in
the evolution of the liver there is seen a thick
layer of the primitive matter ; whilst, on the
contrary, the parotid gland in the embryo of a
calf two inches seven lines long, consists of a
tube visible to the naked eye, and not at all
covered by parenchyma.

5. The mode in which the secondary tubes
are developed has been observed with great
care ; and it is distinctly established that they
do not proceed as mere elongations of the pri-
marif cavity, but are formed in an indepen-
dent manner. One of the latest writers on the
development of the body, Valentin* has
given a very exact account of the process in all
the glands. He states that in the neighbour-
hood of the chief duct or of a branch of it,
small oblong accumulations of the plastic
mass are formed, which become hollowed in
the interior, and these hollows, at first inde-
pendent of the principal cavity* subsequently
communicate with it. It is also observed by
Muller that in the kidney of Batrachian Am-
phibia, the secreting tubes first appear as

* Loc. cit. p. 521, et alibi.

vesicles which are formed before the ureter,
and therefore independently of the principal
duct.* As the tubes become more developed,
the plastic substance around them, by acquiring
greater firmness, constitutes their walls, and
thus determines their exact form and limits.
It is necessary to state that in every instance
without an exception, the newly-formed canals
end in ccecal extremities, which are often
rather swollen, presenting a pedunculated ap-
pearance.

6. In proportion as the canals become
formed in the substance of the plastic mass,
this latter gradually diminishes in quantity,
till ultimately, when all the tubuli are formed,
it is so much reduced that it merely fills up the
interlobular fissures, and is in fact converted
into the interstitial cellular tissue.

7. At the same period of time that the tubes
are thus being formed, the bloodvessels are
being developed ; and, as Muller and Valentin
remark, a very close parallel is presented in the
generation of these the essential parts of the
gland. As in the case of the tubes, there are
at first little masses, or islands, of the plastic
substance, which subsequently join together,
and their interior becoming liquified, a num-
ber of little channels are formed containing a
circulating fluid, and which channels, by the
subsequent consolidation of their walls, are at
length formed into perfect bloodvessels. Like
the tubes these vessels are at first independent ;
they afterwards open into larger trunks and
ultimately into the heart. It is proper to
remark that, although there is such a corres-
pondence in the process of development in
each instance, the bloodvessels are formed
quite independently of the canals ; that they
occupy a different part of the plastic mass;
and that they never present that continuity
which ought at this epoch to have been very
apparent, if the theory of Ruysch had been
founded in truth.

8. The several glands are not developed
equally early, some having their organization
much more advanced than others; thus at the
time when the pancreas is so far formed as to
contain an immense number of canals, the
parotid presents only a single duct or a few
ramifications.f The principle which regulates
the relative degree of development has evi-
dently reference to the importance of the organ
during the foetal life ; and in this respect the
liver is most remarkable, for that body being,
as I conceive, the true decarbonising organ in
the animal kingdom, and therefore its func-
tions being doubtless necessary in the foetus,
very quickly acquires a high degree of organi-
zation, so much so that, as we learn from all
observations, it very speedily fills the greatest
part of the abdomen. J

* De Gland. Struct, p. 87.

t Rathke in Burdach s Phy. II. Band. p. 576.
Valentin, 1. c. p. 225.

$ In the embryo of a sheep five lines in length,
Valentin has found the liver filling half of the
abdominal cavity ; and in the embryo eight lines
long, that organ constitutes three-fourths of the
bulk of the viscera contained in the peritoneum:

494

GLOSSO-PHARYNGEAL NERVE.

Lastly, The laws in obedience to which the
glands are developed, are as universal as to
their existence in the animal kingdom, as those
which regulate the formation of the nervous,
osseous, and vascular systems; and thus it
may be noticed that the complex glands of
man and the mammalia, such as the parotid,
the pancreas, and the liver, pass, in the various
epochs of their development, through those
forms, which in the lower animals, and espe-
cially in the invertebrated tribes, constitute the
permanent structure. It may also be stated,
that when any particular gland first appears in
the animal series, it presents the most simple
structure, although the same gland in the
higher classes acquires the highest degree of
complexity. Thus, the liver in insects is tu-
bular, and in many of the amphibia excavated
into large cells ; the pancreas in fishes consists
of separate tubuli; the salivary glands of birds
are extremely simple ; so also are the mam-
mary glands in the Cetacea, and the prostate
glands in many of the Mammalia.

BIBLIOGRAPHY. — Malpighi, De vise, struct.
cap. iii. p. 18, et alibi ; De format. Pulli in ovo,
p. 20. Ruysch, Opera omnia, torn. iii. Holler,
Elem. Phys. ii. Ferrein, Mem. de 1'Acad. Roy.
des Sc. 1749. Cuvier, Le9ons d'Anat. Comp. torn.
iv. Rolando, Journ. Comp. des Sc. Med. torn. xvi.
The Treatises of Bichat, Meckel, and Beclard on
Gen. Anat. Mutter, De gland, secernent, struct,
penit. Handb. der Phy. I. Band. p. 418. Trans,
of ditto by Baly, vol. i. p. 441. Burdach, Phy.
II. Band. edit. 1837, pp. 258, 264, 287, 376, 375,
et alibi. This volume contains a large collection
of the most important facts relative to the deve-
lopment of the several organs, V. Band. p. 36
et seq. Kiernan in Phil. Trans. 1833. Valentin,
Handb. der Entwickelungs -geschichte, pp. 495,
514, 521, 533. Baer, De ovo Mammal., and in
Burdach's Phy. Cams, Anat. Comp. par Jour-
dan, torn. ii. Grant's Lect. on Comp. Anat. in
Lancet, 1833-34. Blumenbach, Man. of Comp.
Anat. by Coulson. Berres, Die Mikroskopischen
Gebilde des Menschlichen Kbrpers.

(R. D. Grainger.)

GLOSSO - PHARYNGEAL NERVE

(nervus glosso-pharyngeus; part of the sixth
pair of Galen and the older anatomists ; part
of the eighth pair of Willis ; the ninth pair of
Soemmerring and some of the modern anato-
mists). The glosso-pharyngeal, par vagum, and
spinal accessory nerves were long considered
as forming a single nerve. Willis first clearly
pointed out the origin and course of the spinal
accessory, separated it from the par vagum, and
termed it the nervus accessorius. The glosso-
pharyngeal appears to have been generally de-
scribed at the time of Willis as a branch of the
par vagum. The term glosso-pharyngeal was
not applied to it until the time of Huber.*
Previous to the time of Willis, however, some
anatomists, more particularly Fallopius,t Eu-

(1. c. p. 517.) Similar observations have been
made in other animals and in the human embryo
by Meckel.

* Epistola Anat. de Nervo Intercostal!, De
Nervis Octavi et Noni Paris, &c. p. 17. Goet.
1744.

t Opera quae adhuc existant omnia, p. 455.
Francof.

stachius,*Bauhinus,fhad shown that this nerve
was really not a mere branch of the par vagum.
The same thing was stated, more or less strongly,
by many subsequent anatomists, more particu-
larly by Winslow,J Haller,§ and Vicq D'Azyr.j)

Soemmerring «H and Andersch** were, how-
ever, the first who fairly separated the glosso-
pharyngeal from the par vagum, and ranked it
as a distinct nerve. The glosso-pharyngei form
the ninth pair of Soemmerring's classification
of the encephalic nerves, and were termed the
eighth pair by Andersch. There can be no
doubt that if we adopt the numerical method
of naming these nerves, the glosso-pharyngei
properly form the ninth pair. To avoid, how-
ever, all the misunderstanding which is apt
to arise from the use of numerical names
when applied to these nerves, the best designa-
tion for the nerve at present under our conside-
ration is the glosso-pharyngeal, derived from its
being principally distributed upon the tongue
and the pharynx. I need scarcely state that,
under the term eighth pair, as it is most gene-
rally used in modern writings, is included the
glosso-pharyngeal, par vagum, and spinal ac-
cessory nerves, ff

Origin. — The glosso-pharyngeal nerve arises
by from two to six filaments from the restiform
body of the medulla oblongata, closely upon
the groove which separates the restiform from
the olivary body. At its origin it is placed im-
mediately above and in the same line with the
par vagum nerve, and between it and the portio
dura of the seventh pair. Its lower margin is
generally separated from the upper margin of
the par vagum by a few small bloodvessels.

From its origin it first proceeds outwards
along with the par vagum and spinal accessory
to reach the foramen lacerum posterius.
Through the anterior and inner part of this
foramen it escapes from the interior of the cra-
nium, and is enclosed in a strong and separate
sheath furnished by the dura mater.JJ In its
passage through the foramen lacerum it is
placed anterior to the par vagum and spinal
accessory and the commencement of the inter-

* Explicatio Tabularum Anatomicarum Eusta-
chii, tab. xviii. Bat. 1744.

t Theatrum Anatomicum, cap. xxiii. p. 659.
Francof. 1605.

| Exposition Anatomique de la Structure du
Corps Humain, torn. iii. p. 106. Amstel. 1743.

§ ElementaPhysiol. torn. iv. cap. xxix. p. 231-2.
Laus. 1562.

|| Traite d'Anatomie et de Physiologic avec dea
planches coloriees, etc. No. iii. p. 56. Paris, 1786.

U" De Basi Encephali et Originibus Nervorum,
&c. in torn. ii. p. 97. Ludwie. Script. Neurol.
Sel. Min. 1792.

** Fragmentum Descrip. Nerv. Cardiac, in torn,
ii. Ludwig. Sc. Neur. Sel. Min. p. 113.

ft Those who may wish to examine at greater
length the literature of this nerve may consult
Soemmerring Oper. Cit. p. 97, and more particu-
larly Kilian Anatomische Untersuchungen iiber
dasneunte Hirnnervenpaar oderden Nervus Glosso-
pharyngeus, p. 1-62. Pesth, 1822.

ft According to Morgagni (Adversar. Anat. vi.
Animad. xii.) and Wrisberg (De Nervis Pharyn-
gis, in torn. iii. p. 52. Ludwig. Script. Neur. Sel.
Min.) this septum separating the glosso-pharyn-
geal from the par vagum is sometimes osseous.

GLOSSO-PHARYNGEAL NERVE.

495

nal jugular vein, which lie in the order here
enumerated. As the nerve issues from the
lower part of the foramen lacerum it forms a
small rounded chord, close to, but still quite
separate from the par vagum, and is situated
between the internal jugular vein and internal
carotid artery. It now leaves the trunk of the
par vagum, proceeds downwards, inwards, and
forwards, passing in front of the internal carotid
artery and behind the styloid muscles, and
joins itself to the stylo-pharyngeus muscle. It
runs at first along the lower margin of this
muscle, and rests on the superior constrictor
of the pharynx which separates it from the
tonsil ; it then mounts on the anterior surface
of the stylo-pharyngeus muscle, and passes be-
tween it and the stylo-glossus to reach the base
of the tongue, upon which it is ultimately dis-
tributed. Occasionally, instead of turning over
the lower edge of the stylo-pharyngeus, it per-
forates this muscle. In following the course
here described, it forms a slight curve, the con-
vexity of which looks downwards, and it sends
off several branches, which are principally dis-
tributed to the pharynx and isthmus of the
fauces. These branches vary very considerably
in size and in number in different subjects, but
the general distribution of the nerve is in all
cases nearly the same. When the branches
are few in number, this is compensated for by
their increased bulk, and when they are more
numerous they are of diminished size. This
nerve generally anastomoses with the par vagum
within the cranium by a pretty distinct branch.*
As the nerve lies within the foramen lacerum it
presents two swellings or ganglia upon it, and
gives off some small branches. The superior of
these two ganglia is considerably smaller than the
inferior, and has been termed the ganglion ju-
gularebyJ. Miiller, (Jig. 225). It is described
by Mullerf as generally present, though small,
placed upon the posterior or external side of
the nerve, and situated at the cranial end of
the foramen lacerum. It can only be distinctly
seen after the dura mater has been removed,
and the upper margin of the opening chiseled
away. I have repeatedly observed this gan-
glion jugulare in the human subject. In one
case which I lately dissected, where it was
comparatively large, very distinct, and pre-
sented undoubtedly all the appearance of a
true ganglion, it appeared to me, after careful
examination, that this swelling does not include
the whole of the nerve, but is confined, as
Miiller states, to the posterior filaments. These
posterior filaments do not seem to differ other-
wise in appearance from the anterior. This
ganglion was first pointed out by Ehrenritter,
and mentioned by Soemmerring on his autho-
rity.]: Very little attention seems to have been
paid to this ganglion, so that when it was lately
re-described by Miiller,§ it was supposed that

« Op. cit. p. 114.

t Handbuch der Physiologic des Menschen.
Erster Band, p. 589.

i Arnold in Tiedemann's Zeitschrift fur Physio-
logic, vol. ii. p. 175, and J. Muller, in his Archiv.
fur Anat. und Phys. &c. 1837. No. ii. p. 275.

$ In Vergl. Jahresbericht Von 1833, Archiv. fur
Anatomic und Physiol. 1834, p. 11.

its existence in the human subject had been
hitherto unknown.* Mayer, of Bonn, had,
previous to this (1833), described two small
swellings upon the root of the glosso-pharyn-
geal in the ox, but he failed to detect any
similar ganglion in the human species. No
nervous filaments either leave or join that part
of the trunk of the nerve upon which the gan-
glion jugulare is placed. The inferior ganglion
(ganglion petrosum, ganglion of Andersch) is
considerably larger than the superior, is of an
oblong shape, and includes all the filaments of
the nerve. It is described by Anderschf as
about five lines in length, and commencing
about four lines below the place where the
nerve perforates the dura mater. No doubt, if
we include all that portion of the trunk of the
nerve which appears to be somewhat increased
in size, it may sometimes measure five lines,
but the true gangliform enlargement is consi-
derably less. As WutzerJ remarks, it is rarely
found to exceed two lines in length. This gan-

Fig. 225.§

Natural size. Magnified about four times.

glion lies in a distinct depression in the pe-
trous portion of the temporal bone, which
Andersch terms receptaculum ganglioli petrosi.
Some branches both proceed from and join
that portion of the nerve occupied by this gan-
glion petrosum. The most important of these
is a small branch which proceeds from the
ganglion into the tympanum (ramus tympani-
cus nervi glosso-pharyngei ; nerve of Jacobson).
The course and distribution of this branch were
partly known to Schmiedal, Andersch, Ehren-
ritter, and Comparetti,|| but were more fully

* I find that Wutzer, in his Monograph " De
Corporis Humani Gangliorum Fabrica atque Usu,"
p. 92, after describing the inferior ganglion of the
glosso-pharyngeal, says, " secundarium ganglion
quod nonnumquam adesse Ehrenritter contendit
mihi non sub oculos cecidit."

t If Andersch is not to be considered the disco-
verer of this ganglion, it cannot be denied that he
first gave a full and clear description of it. (Op.
cit. p. 115.) Kilian (Op. cit. p. 30 and 75) con-
tends that the existence of this ganglion was known
to Winslow. In evidence of this he quotes the
following sentence from his Exposit. Anatom. torn,
iii. " les deux portions (nervus glosso-pharyngeus
et nervus vagus) sont edroitement collees ensemble
et communiquent de pan et d'autre par des filamens
qui grossissent un peu la petite portion (glosso-
pharyngeal.)'"

§ [This figure is taken from a dissection by Mr.

t Op. cit. p. 91.

§ [This figure is

Walker in the Webb-street School of Anatomy.
The Editor is indebted for it to the kindness of his
friend Mr. Grainger.]

|| Vide Muller's Archiv. fur Anat. und Physiol.
&c. No. ii. 1837. p. 281.

496

GLOSSO-PHARYNGEAL NERVE.

described by Jacobson.* The nervus tympa-
nicus enters a canal in the petrous portion of
the temporal bone, and there anastomoses with
the Vidian and the carotid plexus of the sym-
pathetic. The orifice of this canal is placed
between the jugular fossa and carotid canal,
and external to the termination of the aqueduct
of the cochlea. The ramus tympamcus is
figured and described by Arnold f as dividing
into six filaments : 1. a filament to the fenestra
rotunda; 2. one to the fenestra oval is ; 3. one
which anastomoses with the sympathetic; 4.
one distributed upon the Eustachian tube ; 5.
one, which he terms nervus petrosus profundus
minor, anastomosing with the spheno-palatme
ganglion ; 6. one, the nervus petrosus superfi-
cialis minor, which anastomoses with a branch
from the otic ganglion or ganglion Arnold i.
The nerve of Jacobson thus forms an anasto-
mosis among the glosso-pharyngeal, the second
and third branches of the fifth pair, and the
superior ganglion of the sympathetic.} A small
branch arises from the ganglion petrosum, as
delineated by Arnold,§ which unites itself to
the auricular branch of the par vagum.||

Two other filaments are generally found con-
nected with that part of the trunk of the nerve
occupied by the ganglion petrosum. These
are a communicating twig between the ganglion
petrosum and ganglion of the par vagum, and
an anastomosing filament of the sympathetic.
As these filaments are very minute, and lie in a
dense fibrous sheath, they can only be displayed
by an exceedingly careful dissection. The
communicating filament between these two
ganglia of the glosso-pharyngeal and par vagum
is short, and passes directly from the one gan-
glion to the other. The communicating filament
from the sympathetic comes from the superior
cervical ganglion, mounts up between the
trunks of the par vagum and glosso-pharyngeal,
and divides into two portions, — one of these
connecting itself to the ganglion petrosum, the
other to the ganglion of the par vagum. The
course and mode of termination of this com-
municating filament of the sympathetic is re-
presented differently by Wutzer^ from the de-
scription here given. I have adopted that
given by Arnold,** since it exactly agrees with
my own dissections. Another branch has been
described as arising from the ganglion petrosum
immediately below the ramus tympanicus, and
passing backwards behind the styloid process,
to anastomose with the trunk of the facial after

* Acta Reg. Soc. Havniensis Medic, torn. v.
Copen. 1818.

t Icones Nervorum Capitis, tab. vii. 1834.

t Cruveilhier (Anatomie Descriptive, torn. iv.
p. 952, 1835) states that, in one subject he found
this ramus tympanicus formed by two branches,
one from the par vagum, the other from the glosso-
pharyngeal. In another subject it was formed by
a branch from the auricular of the pneumo-gastric
united with one from the glosso-pharyngeal.

§ Op. cit. plates iii and v.

|| It appears that the ramus auricularis of the
par vagum was described even to both its branches
by Comparetti, p. 129, De Aure Interna, &c.

11 Op. cit. fig. vii.

** Op. cit. tab. iv.

its exit from the stylo-mastoid foramen * We
here see that the anatomy of that portion of the
glosso-pharyngeal nerve which lies within the
foramen lacerum is very complicated, but it
must be at the same time obvious that it em-
braces considerations of great interest in a phy-
siological point of view.

What the true nature of these two ganglia is,
we cannot at present venture positively to de-
cide. I may mention, however, that Miillerf
states that he is satisfied, that the superior gan-
glion or ganglion jugulare resembles the Casse-
rian ganglion upon the trigeminus or fifth pair,
and those upon the posterior roots of the spinal
nerves, for while one portion of the nerve
swells into a ganglion, the other passes by
without assisting in its formation. On the
other hand, he believes that the inferior gan-
glion differs decidedly from those upon the
posterior roots of the spinal nerves, and resem-
bles the swelling which is occasionally found
upon a nerve where it is joined by branches
from the sympathetic. The ramus tympanicus,
according to his view, belongs to the sympa-
thetic system of nerves.}

On escaping from the foramen lacerum the
glosso - pharyngeal occasionally forms direct
anastomoses with the par vagum, spinal acces-
sory, and superior ganglion of the sympathetic ;
at other times it only anastomoses with these
through its branches.

Digastric and stylo-hyoid branch. — The
origin of this branch is far from being regular.
It frequently arises from the external side of the
nerve soon after its exit from the foramen lace-
rum. It ramifies, as its name implies, in the
digastric and stylo-hyoid muscles. The fila-
ments of this nerve anastomose in the substance
of the digastric muscle with the digastric branch
of the portio dura.§

Carotid branches are two or more in num-
ber, and pass from the convexity of the nerve
or from some of its pharyngeal branches, and
proceed upon the surface of the internal carotid,
where they form a very evident anastomosis with
the sympathetic, with the pharyngeal, and other
branches of the par vagum, and assist in form-
ing the plexuses around the carotid arteries.
They have been traced downwards for a consi-
derable extent, and found to anastomose with
the superior and even with the middle cardiac
nerves.

Pharyngeal branches. — The nerve next fur-
nishes the pharyngeal branches, which are from
two to four in number. The largest of these
proceed downwards, and their ramifications can
be traced over the whole of the pharynx, but
more particularly over its upper and middle

* Cruveilhier, op. cit. p. 953. He looks upon
this twig as the rudiment of a considerable branch
of the facial, which he found in one case partly to
replace the glosso-pharyngeal. See also torn. iii.
p. 424.

t Archiv. fur Anat. &c. No. ii. 1837, p. 276.

| Handbuch der Physiol. Erster Band.

$ Mr. Swan, in plate xvii. Jig. 2 and 3, of his
" Demonstrations of the Nerves of the Human
Body," figures this communication as formed by a
filament of the digastric branch of the facial going
to join the trunk of the glosso-pharyngeal.

OLOSSO-PHARYNGEAL NERVE.

437

portions. One or generally more of these pha-
ryngeal brandies perforate the stylo-pharyngeus
muscle, and can be traced partly downwards up-
on the middle constrictor, partly upVards upon
the superior constrictor and mucous membrane
of the fauces, and also partly forwards upon the
surface of the tonsils. I have traced one of
the^e pharyngeal branches through the posterior
part of the hyo-glossus muscle into the mucous
membrane at the side of the posterior part of
the tongue. These pharyngeal branches, by
their anastomoses with the pharyngeal branches
of the par vagum and pharyngeal branches of
the sympathetic, form what is called the^a-
ryngeal plexus of nerves.* A distinct swelling
is frequently found over the internal carotid
artery, formed by the confluence of the princi-
pal pharyngeal branches of the glosso-pharyn-
geus, of the superior pharyngeal branch of the
par vagum, and the pharyngeal branches of the
superior ganglion of the sympathetic. This
swelling varies considerably in size and appear-
ance. Hubert describes a small ganglion in
the pharyngeal plexus. HaaseJ shortly de-
scribes this swelling as a gangliform enlarge-
ment. \Vrisberg§ states that a ganglion, of the
size of the ophthalmic, is placed at the conflu-
ence of these nerves. Scarpajj describes and
figures it as a gangliform plexus more particu-
larly, connected with the pharyngeal branch of
the par vagum. Wutzerlf states that he has
been unable to detect this pharyngeal ganglion.
Kilian** and Arnold,ft but more particularly
Kilian, figure it as a plexus. Though I would
not deny the occasional existence of a small
ganglion in this region, yet I believe it will be
found that this swelling is generally formed by
the cellular tissue binding together these
branches as they anastomose with and cross
each other.Jt

Lingual branches. — After the trunk of the
nerve has furnished the pharyngeal branches, it
sends off from its concave side some small
twigs upon the surface of the tonsils. It then
forms the lingual portion of the nerve, passes
into the base of the tongue below the stylo-
glossus and posterior margin of the hyo-glossus
muscle, where it divides into three or four
branches. The superior of these is principally
distributed upon the posterior part of the sides
of the tongue, and sends some twigs backwards
upon the palato-glossus muscle and mucous
membrane of the fauces, where they anastomose
with the other tonsillitic twigs. The middle
part of the termination of the nerve passes

* A small twig from the hypo-glossal nerve can
sometimes be traced into this plexus. As the su-
perior pharyngeal branch of the par vagum is partly
formed by the spinal accessory, this last nerve must
assist in the formation of this plexus.

t Op. cit. p. 18.

$ De Nervo phrenico dextri lateris duplici,
&c. Ludwig, torn. iii. p. 115.

$ Op. cit. p. 58.

jj Tabulae Neurologies, plate 2.

1 Op. cit. p. 91.

** Op. cit. tab. ii. fig. 5.

tt Op. cit. tab. iv.

t$ The glosso-pharyngeal in the dog is generally
considerably increased in size where th'e principal
pharyngeal branches are given off.
VOL. II.

through the lingualis and hyo-glossus muscles
to reach the mucous membrane and papillae at
the side of the base of the tongue. The re-
mainder of the nerve perforates the genio-hyo-
glossus to reach the mucous membrane and
papillae in the middle of the base of the tongue.
The distribution of these twigs is confined to
the mucous surface at the base of the tongue,
and do not extend beyond an inch in front of
the foramen coecum. They pass through the
muscles of the tongue without giving any fila-
ments to them.*

Tonsillitic twigs.— The different twigs of this
nerve which we have described as passing to
the tonsils, form an intricate plexus, posterior
to and around these bodies, which has been
called the circulus tonsillaris. These tonsillitic
twigs are ultimately intermixed with the as-
cending filaments of the pharyngeal branch of
the par vagum, and pass in considerable num-
bers to the isthmus of the fauces and soft
palate. They anastomose also with the pos-
terior palatine branches of the second branch
of the fifth pair, and, according to Wrisberg,f
with a filament from the third branch of the
fifth.

In repeated dissections, both upon the hu-
man subject and the dog, I have found, in
tracing the branches of this nerve to their ulti-
mate distribution upon the pharynx and fauces,
that those branches of the glosso-pharyngeal
which do not anastomose with the pharyngeal
branch of the par vagum are principally distri-
buted upon the mucous membrane, and that
comparatively a small number of these fila-
ments seem to terminate in the muscular fibre.
The uncombined twigs of the pharyngeal
branches of the par vagum are, on the other
hand, distributed entirely to the muscular fibre.
In a dissection of this kind care must be taken
to select those twigs only which proceed to
their distribution without exchanging filaments
with any other nerve. It can be made more
favourably in the dog than in the human spe-
cies. The glosso-pharyngeus is still distri-
buted upon the tongue in birds, in the frog,
and certain of the amphibia, while this organ
receives no branch from the fifth pair, and from
this circumstance it has been considered the
nervus gustatorius of these animals.} In
fishes there is a branch of the par vagum
called glosso-pharyngeal, which escapes from
the base of the cranium by a separate opening,
and is distributed upon the gills, and also upon
the tongue as far as the skin of the mouth.

Physiology. — It is only to the labours of
anatomists and physiologists within the last
few years that we are to look for any thing

* In tracing these nerves, it has appeared to me
that a few minute filaments terminate in the mus-
cles of the tongue, but these are exceedingly few
and small. The statement of Wrisberg, that the
deep branches of the lingual portion of the glosso-
pharyngeal are distributed to the muscles of the
tongue, is opposed to the observations of the best
anatomists, who have since his time examined the
ultimate distribution of this nerve.

f Op. cit. p. 51.

i Handbuch der Physiologic, etc. Erster Band,
p. 590, 772.

2 L

498

GLOSSO-PHARYNGEAL NERVE.

like accurate data in enabling us to judge of
the functions of this nerve. Its deep situa-
tion, its proximity to important parts, and the
consequent difficulty of exposing it in the living
animal, have until very lately deterred physio-
logists from making it an object of experimental
investigation. Some have supposed that it
supplies the nervous filaments upon which the
sense of taste at the root of the tongue de-
pends, while the third branch of the fifth pair
furnishes those of the anterior part of this
organ. Mr. Mayo* states that " when this
nerve is pinched in an ass recently killed, a
distinct convulsive action ensues, apparently
including and limited to the stylo-pharyngeus
muscle and upper part of the pharynx." He
concluded from this that the glosso-pharyngeal
is in part, probably, a nerve of voluntary mo-
tion ; and from its distribution upon the sur-
face at the root of the tongue, that it is also
partly a nerve of common sensation. Sir C.
Bell believes that this is the respiratory nerve
of the tongue and pharynx, associating the
movements of those organs 'with the muscles
of respiration in speech and in deglutition.
And we find it stated by Mr. Shaw f that its
power of combining the movements of the
tongue and pharynx in deglutition " has been
shown by several experiments, the results of
which were very curious, and corroborative of
the views deduced from comparative anatomy."
Panizza J has undertaken an experimental in-
vestigation into the functions of the nerve, and
obtained very unexpected results.

From these we are led to believe that when
this nerve is pricked in a living animal, this is
attended by no indications of suffering and no
convulsive movements; that section of both
nerves is followed by loss of taste, while the
tactile sensibility of the tongue and the mus-
cular movements of deglutition and mastication
remain unimpaired ; that section of the fifth
pair is on the contrary followed by loss of
common sensation without any apparent effect
upon the taste. From these and other experi-
ments upon the nerves supplying the tongue,
he concludes that the glosso-pharyngeal is the
nerve upon which the sense of taste depends,
and is therefore the true gustatory nerve. Dr.
M. Hall and the late Mr. Broughton§ had,
from experiments performed previous to the
publication of those of Panizza, arrived at the
conclusion that this nerve is not a nerve of com-
mon sensation. These gentlemen likewise
reported at the meeting of the British As-
sociation for 1836 an experiment, the results
of which were in exact accordance with those
obtained by Panizza upon this nerve, but no
details of these experiments have yet been pub-

* Anatomical and Physiological Commentaries,
n. ii. p. 11. 1822.

+ London Medical and Physical Journal.vol. xlix.
1823.

f Edinburgh Medical and Surgical Journal, Jan.
1836, and Medical Gazette, Sept. 1835.

§ Fourth Report of British Scientific Association,
and Mr. Broughton, in vol. xlv. of Edinburgh Me-
dical and Surgical Journal.

lished. Mr. Mayo* has stated several objec-
tions to these conclusions of Panizza. He rests
his grounds of dissent principally upon the
fact that the distribution of this nerve is con-
fined to the posterior part of the tongue; while
the sense of taste, he maintains, is also present in
the anterior part of that organ, and consequently
it cannot, in that part at least, depend upon the
glosso-pharyngeal. The persistence of the sense
of taste after section of the fifth pair may, Mr.
Mayo supposes, depend upon the palatine twigs
of the second branch of the fifth pair distri-
buted upon the palate and isthmus of the fauces.
Mr. Mayo attempted to decide the matter by
experiment, but he did not carry this suffi-
ciently far to obtain any satisfactory results.
Dr. Alcock-j- has also lately examined into the
functions of this nerve experimentally, and has
arrived at conclusions at direct variance with
those of Panizza; for according to Dr. Alcock,
when this nerve is exposed and irritated in the
living animal, it excites pain and spasmodic
contractions of the pharynx and muscles of the
throat. When divided on both sides, the ani-
mal's taste, " to say the least of it, did not ap-
pear to be much affected." He believes that the
sense of taste enjoys " two media of percep-
tion, and that these are the glosso-pharyngeal
nerve and the lingual and palatine branches of
the fifth." He also states that the muscular
movements of deglutition are very much im-
paired after section of the nerve on both sides.
He concludes, then, that the glosso-pharyngeal
are sentient nerves, and also influence muscular
motion. He, however, is doubtful in what
manner these muscular movements are excited
by irritation of this nerve, for though " dis-
posed to regard the result in question as the
effect of a sentient impression excited through
the nerve, and referred to the interior of the
pharynx," from the fact that this movement ex-
tends to muscles not supplied by this nerve,
and forms an associated movement, he admits
" that the circumstance may be as well ex-
plained by an exalted degree of muscular
excitement, or by a higher one than that ne-
cessary to produce the simple starting." Pro-
fessor M tiller J believes that an examination of
the position of the ganglion jugulare will de-
cide that the glosso-pharyngeal is a mixed
nerve, and he maintains that the distribution of
this nerve, partly for sensation (mucous mem-
brane of the root of tongue), partly for the
movements of muscles (stylo-pharyngeus and
pharynx), exactly resembles that of the two
roots of the nervus trigeminus. Unable amidst
these discordant statements to come to any sa-
tisfactory conclusions upon the proper func-
tions of this nerve, I entered into a lengthened
experimental and anatomical investigation for
this purpose. The experiments were twenty-
seven in number, and were performed upon as

* Medical Gazette, Oct. 1835, and 4th edit, of
Outlines of Physiology, p. 314.

t Dublin Journal of Chemical and Medical Sci-
ence, Nov. 1836.

t Archiv fur Anat. und Physiol. etc. n. ii.
1837, P. 276.

GLOSSO-PHARYNGEAL NERVE.

499

many different dogs. Seventeen of these were
upon the living animal, with the view of as-
certaining if this nerve were to be considered
both a nerve of sensation and motion, and what
are the effects of its section upon the associated
movements of deglutition, and on the sense of
taste. The other ten were performed on ani-
mals immediately after they had been deprived
of sensation, for the purpose of satisfying my-
self to what extent it was to be considered a
motor nerve. The most remarkable effect wit-
nessed in these experiments was an extensive
convulsive movement of the muscles of the
throat and lower part of the face on irritating
this nerve in the living animal, provided the
irritation was applied to the trunk of the nerve
before it had given off its pharyngeal branches,
or to one of these pharyngeal branches sepa-
rately. These movements were equally well
marked upon pinching the cranial end of the
cut nerve after it had been divided at its exit
from the foramen lacerum, as when the trunk
of the nerve and all its branches were entire.
In some of these experiments we observed a
remarkable difference between the effects of irri-
tating this nerve before and after it had given off
its pharyneeal branches, which is valuable on
this account, that it may explain the discrepan-
cies between the results obtained by Panizza,
Dr. M. Hall, and the late Mr. Broughton on
the one hand, and Dr. Alcock on the other.
For though I do not mean to affirm that pinch-
ing the lingual portion of the nerve is never
followed by indications of suffering, (for from
the irregularity in the origin of the pharyngeal
twigs, and the difficulty of judging at the
bottom of a deep wound in the living animal
at what particular part these are all given off, it
is generally impossible to decide where the
lingual portion may be said to begin,) yet I
have no hesitation in saying that if in several
of these experiments we had operated only on
that portion of the nerve which first presented
itself, and not proceeded to dissect it back-
wards towards its place of exit from the cra-
nium, we should have gone away with the
impression that the irritation of this nerve was
followed by no convulsive movements, and
little if any indications of suffering.

From a review of all the experiments which
I have performed upon the glosso-pharyngeal
nerves, I am inclined to draw the following
conclusions : —

1. That this is a nerve of common sensation,
as indicated by the unequivocal expression of
pain by the animal, when the nerve is pricked,
pinched, or cut.

2. That mechanical or chemical irritation
of this nerve before it has given off its pha-
ryngeal branches, or of any of these branches
individually, is followed by extensive muscular
movements of the throat and lower part of the
face.

3. That the muscular movements thus ex-
cited depend, not upon any influence extending
downwards along the branches of the nerve to
the muscles moved, but upon a reflex action
transmitted through the central organs of the
nervous system.

4. That these pharyngeal branches of live
glosso-pharyngeal nerve possess endowments
connected with the peculiar sensations of the
mucous membrane upon which they are distri-
buted, though we cannot pretend to say posi-
tively in what these consist.

5. That this cannot be the sole nerve upon
which all these sensations depend, since the
perfect division of the trunk of the nerve on
both sides does not interfere with the perfect
performance of the function of deglutition.

6. That mechanical or chemical irritation
of the nerve, immediately after the animal has
been killed, is not followed by any muscular
movements when sufficient care is taken to in-
sulate it from the pharyngeal branch of the par
vagum. And we here observe an important
difference between the movements excited by
irritation of the glosso-pharyngeal and those of
a motor nerve, for while the movements pro-
duced by the irritation of the glosso-pharyngeal
are arrested as soon as the functions of the
central organs of the nervous system have
ceased, those from irritation of a motor nerve
such as the pharyngeal branch of the par
vagum, continue for some time after this, and
when all connexion between it and the medulla
oblongata has been cut off by the section of
the nerve.

7. That the sense of taste is sufficiently
acute, after perfect section of the nerve on both
sides, to enable the animal readily to recog-
nize bitter substances.

8. That it probably may participate with
other nerves in the performance of the function
of taste, but it certainly is not the special nerve
of that sense.

The sense of thirst which is referred to the
fauces and pharynx does not appear to de-
pend entirely upon the presence of this nerve.
The animals in which it was divided lapped
water of their own accord. I observed one of
those in which the nerves were found satisfac-
torily divided, rise, though feeble, walk up to
a dish containing water, lap some of it, and
return again to the straw upon which he was
previously lying.

In all experiments upon the glosso-pharyn-
geal nerve in the dog, too great care cannot be
taken to avoid the pharyngeal branch of the
par vagum, which is sometimes situated in im-
mediate contact with it, at other times one or
two lines below it, and is frequently united to
it by a considerable communicating branch, so
that it may readily be mistaken for a large pha-
ryngeal branch of the glosso-pharyngeal. This
precaution is the more necessary, as I am con-
fident that these two nerves differ from each
other in function, and this must consequently
seriously affect the results. I attribute the dif-
ficulty of deglutition after section of this nerve
in the living animal, and the muscular move-
ments on irritating it in the animal recently
killed, observed by two of the preceding ex-
perimenters, to a want of sufficient precaution in
separating these nerves from each other. These
results were only observed by me when the
pharyngeal branch of the par vagum was im-
plicated in the experiment.

2 L 2

500

GLUTAEAL REGION.

Withx4hegard to the argument in favour of
the radial properties of this nerve, drawn by
Mu'ller from its anatomy, it appears to me that
this analogical mode of investigation, valuable
though it is, must be permitted to yield to the
more positive observations obtained from expe-
riment. And though it may be granted that
the apparent limitation of the ganglion jugu-
lare to the posterior filaments of this nerve
causes it here to resemble closely the double
roots of the spinal nerves, yet we must be
wary in drawing analogies between the glosso-
pharyngeal and spinal nerves, since we have
another ganglion situated immediately below
this, viz. the ganglion petrosum, which involves
the whole of the nerve, and to this assuredly
we have no analogical structure in the spinal
nerves. No doubt Miiller supposes that this
inferior ganglion differs from those placed upon
the posterior roots of the spinal nerves, and
that it. belongs to the sympathetic system. But
as nothing like conclusive proof is advanced
in support of this opinion, we may in the mean
time reasonably suspend our belief as to the
probable influence which this lower ganglion
may exert upon the functions of the nerve.

Of course the fact that some of the filaments
of the glosso-pharyngeal terminate in the mus-
cular fibre, is no proof that these filaments are
motal, for the muscular bundles have their sen-
sitive as well as their motal filaments.

(John Reid.)

GLUT^AL REGION, (Surgical Anatomy.)
(Fr. region fessiere.) The glutaeal region may
be defined with tolerable precision to be all that
space external to the pelvis which is covered
by the glutsei muscles of each side. Its boun-
daries seem naturally to be the crista of the
ilium above; behind, the mesian line as low
down as the point of the coccyx ; before, a line
drawn from the anterior superior spinous pro-
cess of the ilium to the trochanter major; and
below, a line drawn from the point of the
coccyx to the insertion of the glutaeus maximus ;
in fact, the inferior margin of this muscle forms
the boundary line. These limits, better defined
than those of most of the anatomical regions,
separate this tract from the lumbar and iliac
regions above, from the superior anterior region
of the thigh in front, from the perineal and
posterior regions of the thigh below, and from
the corresponding part of the opposite side at
the posterior mesian line. This space, which
does not comprise many points of importance
in surgical anatomy, is yet not without interest.
Here are the glutaeal and ischiadic arteries, also
the commencement of the course of the great
sciatic nerve. The internal pudic artery" also
skirts along the inferior edge of the glutaeal
region, but this will be best considered as part
of the regi'on of the perineum.

The first thing that strikes us in the exami-
nation of this region is the great density and
thickness of the integuments ; they are inferior
in this respect only to the sole of the foot.
This density is, however, found greater pro-
portionally in the true skin than in the cuticle,
which retains much of the softness and pliabi-

lity of the same covering in other parts of the
body, and the end of this is evident, since
whatever the pressure may be upon the glutoeal
parts, a dense state of the cuticle in any degree
similar to the sole of the foot would, in the
varied positions and movements of the trunk,
be quite incompatible with comfort. On the
other hand, the true skin, though pliant, is
remarkably dense and strong, its fibres almost
tendinous in structure, interlacing each other
in every direction, and united underneath to a
strong but rather loose cellular tissue which
connects it to the glutaeus muscle. It is to the
laxity of this cellular connexion that the inte-
guments of this part are partly indebted for
that pliability which enables us to rest with
ease and comfort upon surfaces of various
degrees of hardness and inequality. It contains
a considerable quantity of fat, which adds to
the softness and elasticity of this cushion, and
is very different from the granular hard fat
found in the plantar region. The density of
the integumental covering of the glutaeal region
varies somewhat in different parts. It is greatest
where it covers the tuber ischii, and gradually
diminishes on all sides except on the side next
the perineum, where the change is very abrupt
from its characteristic density to the extreme
thinness and delicacy of the perineal covering.
The peculiarity of structure of the integument
covering the glutsei should be borne in mind
by the surgeon in the treatment of diseases of
this part. Abscesses should on this account
be earlier opened from the obstacle thus pre-
sented to their pointing. It is on this account
also, probably, that we so generally find
abscesses here accompanied with sloughing of
the cellular tissue, which is best obviated by an
early opening.

The fleshy fibres of the glutaeus maxirnus
are covered by a somewhat denser stratum of
cellular tissue, forming an aponeurosis distinct
from the fascia lata of the thigh, though conti-
nuous with it at the anterior edge of the muscle,
where the fascia lata lies upon the anterior half
of the glutaeus medius. The great glutaeus is
composed of coarse and loosely connected
fasciculi, running in a direction downwards
and forwards. It commences by a somewhat
semicircular line of origin from the posterior
two-thirds of the crista ilii, from the side of the
sacrum and of the coccyx. From this origin
the fibres run somewhat converging towards
the great trochanter and upper part of the
linea aspera. This direction of the fibres
should be borne in mind in connexion with all
remedial manipulations on this part, that the
position in which the limb should be placed
may be chosen most favourably for the relaxing
of the muscle. The other muscles which are
in this neighbourhood, and all of which move
the thigh-bone, are so much smaller than this
great muscle that the relaxing of this is of the
first importance, and the position must be
chosen with reference almost entirely to this.

On reflecting the glutaeus maximus the fol-
lowing parts are brought into view : — 1st, several
large branches of arteries and veins, which were
divided in reflecting the muscle, and which

GLUTVEAL REGION.

501

passed into the substance of the great glutaeus
muscle; these are from the glutaeal and ischiatic
arteries, and appear principally at the upper
and posterior part of the glutaeus medius;
2d, the whole of the glutaeus medius, the pos-
terior two-thirds of which had been covered by
the larger muscle ; 3d, at the posterior edge of
the glutaeus medius is the pyriformis muscle part-
ly concealed by it, and coming out of the supe-
rior sacro-sciatic foramen ; 4th, next below the
pyriformis lie the two gemelli, with the tendon
of the obturator intemus between them, and
below these is the quadratus femoris, having
underneath it the strong tendon of the obturator
extemus; 5th, the great sciatic nerve is seen
emerging from the superior sacro-sciatic fora-
men near the sciatic artery. Sometimes it
conies out entirely below the pyriformis; some-
times it descends in two branches, one of which
perforates that muscle, and they then unite.
The trunk passes directly downwards, cross-
ing the rotator muscles of the hip, and pass-
ing between the projecting tuberosity of the
ischium and the trochanter major. In this
part of its course it is accompanied by the
sciatic artery, which is seen about half an inch
to the internal or sacral side of the nerve, and
sends one considerable branch to supply the
nerve, and runs tortuously imbedded in its
neurilema. The course which the nerve and
artery here take will be represented by a line
drawn from the posterior superior spinous pro-
cess of the ilium to a spot midway between
the tuber ischii and trochanter major. Lastly,
in this view are exposed the bursal sacs, of
which there are several between the glutaeus
maximus and the subjacent pails. The most
considerable is found between it and the external
surface of the trochanter major. A consider-
able but smaller one is placed between its broad
tendinous expansion and the upper part of the
vastus externus, and two smaller ones com-
monly between the muscle and the os femoris
at the upper and back part of the thigh. The
ischiatic artery at the commencement of its
course is smaller than the glutaeal, and comes
down over the pyriformis muscle, and makes
its exit from the pelvis through the lower part
of the sciatic notch, between the pyriform and
levator ani muscles, above the lesser sciatic
ligament, and in front of the sciatic nerve ; it
sometimes passes between the roots of this
nerve. On the dorsum of the pelvis the sciatic
artery is covered by the glutaeus maximus
muscle, and may be seen by a similar dissec-
tion to that which exposes the glutaeal artery,
excepting that it is found about an inch and a
half lower down than the last-named vessel.

The glutaeal artery comes out of the pelvis
at the upper part of the sciatic notch in com-
pany with the superior glutaeal nerve and vein.
It immediately winds upwards upon the dorsum
ilii, keeping close to the bone, and shortly
after its arrival upon the dorsum it divides into
branches principally distributed to the glutaeal
muscles. To expose this artery and its branches
in dissection, it is necessary to proceed as in
the dissection of the glutaeus maximus muscle.

Next divide this muscle in a line from the
posterior superior spine of the ilium to the
tuberosity of the ischium. In making this dis-
section several large arteries and veins must be
injured. If the edges of the muscle be now
separated and the subjacent cellular membrane
removed, the glutaeal artery, accompanied by
one or two large veins and by the glutaeal nerve,
may be seen escaping from the sciatic notch
above the pyriform muscle, between it and the
glutaeus medius. This artery, as it escapes from
the pelvis, lies three inches and a half from the
mesian line, or from the spinous processes of
the sacrum.

The glutaeal and ischiadic arteries, as we have
seen, are covered by the glutaeus maximus mus-
cle, and lie at such a depth from the surface
that they are not very liable to injury. Wounds,
however, of this part do occasionally implicate
these vessels, either in their large branches or
even the trunks themselves, and they have been
affected with aneurism, an instance of which
is mentioned by Mr. J. Bell,* and which
attained a considerable size. In the case of a
wound, its direction will lead us to the
situation of the artery ; and in the instance of
aneurism just mentioned, Mr. Bell ventured to
lay open the sac and thus reach the mouth of
the glutaeal artery, which he secured by liga-
ture, and this perhaps might be accomplished
in a very emaciated person; but generally
speaking the artery lies so deep, and the vessels
which must be wounded in making the neces-
sary incisions would by their bleeding so ob-
scure the operation, that the most experienced
surgeons do not recommend the attempt under
ordinary circumstances, but prefer the operation
of tying the internal iliac.f As a guide, how-
ever, to the situation of the glutaeal artery,
whether in the examination of a wound or in
operating upon it, its position on the dorsum
of the pelvis may be ascertained by drawing a
line from the posterior spinous process of the
ilium to the middle of the space between the
tuberosity of the ischium and trochanter major.
If this line is divided into three, the glutaeal
artery will be found emerging from the pelvis
at the juncture of its upper and middle thirds.}

To return to the consideration of the anato-
mical structures which we expose in succession.
We are struck with the difference in texture of
the three glutaei muscles. The fibres of the
two smaller glutaei are of moderate size and
strength, while those of the larger glutaeus are
remarkable for their coarseness and large dimen-
sions. The relative situation of the three
muscles is also important. The position and
direction of the glutaeus maximus is just in
that line in which the greatest vigour of action
is required to erect the body by drawing the
back part of the pelvis towards the trochanter
major. In this operation it is assisted by the
position of the glutaeus medius and minimus,

* Principles of Surgery, vol. i. p. 421.

t See Med. Chir. Trans, vol. v. Also Guthrie on
Diseases of Arteries, p. 364.

| See Harrison's Surgical Anatomy of the Art«-
ries, vol. ii. p. 100.

502

GLUTVEAL REGION.

the posterior fibres of which are covered by the
glutaeus maximus. These anterior fibres have a
different action, varying in the different posi-
tions of the body in relation to the thigh, and,
according to this, consisting either in rotation
inwards, abduction, or flexion of the femur, or,
this bone being fixed, assisting in the various
anterior movements of the pelvis upon the thigh.
At the posterior edge of the middle glutaeus
is the pyriformis coming out of the upper open-
ing of the sciatic notch. Here, as we have
seen, the glutaeal artery is also emerging from
the pelvis and winding round the upper edge
of the notch. This, therefore, will be the situa-
tion of an aneurism of this artery, and a pul-
sating tumour being detected in the situation
just indicated by measure, as the seat of this
vessel, will be a very strong ground for deciding
both as to the disease and the vessel diseased.
A case lately came under our notice of a very
obscure character in which a swelling was
situated precisely in the position of the glutaeal
artery, but without pulsation or any other sym-
ptom of aneurism. The swelling was at first
indistinct, but as the surrounding parts wasted
under the effect of disease it became more pro-
minent. It was firm to the touch and rather
moveable, and about the size of a hen's egg.
But the principal part of the disease showed
itself within the pelvis in a tumour consisting
almost entirely of coagulum, as was proved by
puncture, situated behind the rectum, and
pressing it forward so as to occupy nearly the
whole pelvis, and obstructing the passage both
of fasces and urine. As there was no decided
symptom of aneurism no operation was at-
tempted for the relief of the case, and as the
girl, who is eighteen years of age, still lingers,
the nature of the disease is not yet cleared up.
But this part also occasionally gives exit to a
hernial tumour, part of the intestines or even
the bladder or ovary becoming thus displaced
and being lodged in the sac.* The superior
opening of the sciatic notch is bounded above
by the notch of the ilium, before by the de-
scending ramus of the ischium, and below and
behind by the superior sacro-sciatic ligament ;
and so large is the opening thus left that we
might expect to find the protrusion of some of
the viscera of the pelvis much more frequently
than we do. Yet so completely is this part
covered and defended by the pyriform muscle,
the plexus of nerves, the glutaei maximus and
medius, that this form of hernia is an extremely
rare occurrence. When it does occur in the adult,
the diagnosis is very difficult while the hernia is
small, owing to the great depth at which it is
situated. When, however, it is congenital, the
nature of the swelling is larger in proportion to
the size of the surrounding parts, and the depth
of the superjacent parts less ; yet even here
Professor Schreger did not at first detect the
nature of the swelling. In fact nothing but
the actual feeling of the guggling of the gas of
the intestines under the finger seems sufficient

* See a summary of cases of ischiatic hernia in
Cooper's First Lines of Surgery.

to discriminate the case, and this is of course
not to be expected when the gut is strangulated .
Indeed, in Dr. Jones's case* the symptoms
were not at all referred by the patient to the
true seat of the disease, and the surgeon was
in consequence never led to make any external
examination of this part. It may be well to
state here the anatomical relations of the hernial
sac in this case, which was carefully dissected.
" A small orifice in the side of the pelvis,
anterior to but a little above the sciatic nerve
and on the fore part of the pyriformis muscle,
led into a bag situated under the glutaeus maxi-
mus muscle, and this was the hernial sac, in
which the portion of intestine had been stran-
gulated. The cellular membrane which con-
nects the sciatic nerve to the surrounding parts
of the ischiatic notch had yielded to the pres-
sure of the peritoneum and viscera. The orifice
of the hernial sac was placed anterior to the
internal iliac artery and vein, below the obtura-
tor artery and above the obturator vein. Its
neck was situated anterior to the sciatic nerve,
and its fundus, which was on the outer part of
the pelvis, was covered by the glutaeus maxi-
mus. Anterior to but a little below the fundus
of the sac, was situated the sciatic nerve,
behind it the glutaeal artery. Above, it was
placed near the bone, and below appeared the
muscles and ligaments of the pelvis."

We must not conclude this article without
a few words on the general form of the glutaeal
region as affording an important means of
diagnosis in disease. In examining this re-
gion in a healthy person we observe, 1st, the
thick rounded prominence of the nates, formed
by the posterior and inferior margin of the
glutaeus maximus ; 2d, the projection of the
trochanter major, only covered by the integu-
ments and the thin tendon of the last-named
muscle; 3d, the projection of the crista ilii,
forming the upper boundary of the region ;
4th, a depression, perpendicular in direction,
between the nates and the trochanter major ;
5th, another depression, slighter than the last
and transverse in direction, between the tro-
chanter and crista ilii.

Now almost all these points become altered
in character and relation in disease. In dislo-
cation of the femur they of course are changed
by the difference in position which the trochan-
ter assumes in common with the head of the
bone ; and according to the unnatural situation
which this occupies, so will the alteration in
the general form of the parts be modified. But
we now speak particularly of the changes of
disease. Even in the inflammatory stage of
disease of the hip-joint, it is surprising how
great is the effect produced upon the nates.
The roundness and fulness gradually go, the
nates looks wasted, and the depression between
this and the trochanter disappears. This wast-
ing, arising from interstitial absorption of the
glutaeus and parts adjacent, is the more striking
as it occurs too rapidly upon the affection of
the joint to be the effect of inaction of the

* See Sir A. Cooper on Hernia, part ii. p. 67.

H/EMATOSINE.

503

muscle, as we have seen it occur in a marked
degree in a rather severe attack of inflammation
of the joint, which readily yielded to treat-
ment.* Then in the more advanced stages of
disease of the joint, the depressions above
mentioned are not only lost, but from morbid
depositions in the neighbourhood of the hip
they become elevated and swollen, and the
sharp prominences of the trochanter lost in the
general fulness of the part.

(A. T. S. Dodd.)

GROIN, REGION OF THE, (Surgical
Anatomy.) (Fr. Vaine, region inguinatc.) The
limits of this region, as understood by most
surgical writers, seem to be wholly artificial.
The groin constitutes the confines of the ab-
domen and the thigh ; and Poupart's ligament
forms a natural line of division between its
femoral and its abdominal portions. A line
drawn horizontally, the subject being erect,
from the anterior superior spinous process of
the ilium to the linea alba, forms the superior
limit of this region, while below it may be
defined by a line parallel to the former one,
and extending from the pubis to the outer part
of the thigh. For the particulars of this region,
see HERNIA, FEMORAL ARTERY, ABDOMEN,
and THIGH, REGIONS OF THE.

(R. B. Todd.)

H^MATOSINE, (a^a, blood, and
to Jail.) The colouring matter of the biood.f
This principle separates with the fibrine of the
blood when that fluid coagulates, and may be
obtained free from adherent albuminous matter
by the process recommended by Berzelius,
which is as follows. The coagulum is first to
be sliced in thin pieces with a sharp knife, and
then carefully washed in separate portions of
distilled water; by these means we separate
the adherent serum, and if the washing is
gently performed, but little haematosine be-
comes washed away with it. The slices thus
prepared are placed on a filter and allowed to
drain : when the draining is complete, the slices
are to be thrown into a glass vessel and broken
up in distilled water; we thus procure a solution
of the colouring matter while any fibrine pre-
sent gradually subsides. The liquor when
poured off is a tolerably pure solution of
haematosine. If it is wished to procure the
principle in the solid form, the solution may
be evaporated at a temperature not exceeding
100° Fahrenheit.

Engelhart prefers heating the solution after
filtration to about 150° Fahrenheit, which deter-
mines the precipitation of the haematosine,
while any albumen which may possibly exist

* There seems to be a law of the animal economy
that when a joint is diseased the muscles moving it
immediately lose tone and bulk, and there is no
more marked symptom of disease of an articulation
than this wasting of the muscles which belong to it.

t Lecanu considers that haematosine is a com-
pound of albumen with a substance which he be-
lieves to be the true colouring matter of the blood,
and which he calls Globuline.

in solution with it, remains dissolved at that
temperature. Engelhart's process yields us
haematosine in its purest form, but when thus
obtained it is no longer soluble in water,
whereas, if procured by evaporation at 100°
Fahrenheit, it is still soluble, and what is very
extraordinary, dry haematosine procured at that
temperature, though it be afterwards subjected
to a heat of 2 12° Fahrenheit, does not lose its
property of dissolving in water. Haematosine
may be described under two forms, viz. in
solution and in the dry state.

The aqueous solution of haematosine is pre-
cipitated by alcohol and the acids. The
alkaline hydro-sulphurets and sulphuretted hy-
drogen change the colour of the solution to
green ; nearly all the metallic and earthy salts
precipitate it. Infusion of galls produces a
pale red precipitate ; gallic acid, however, does
not show this effect. Chlorine passed through
a solution of haematosine decolorizes it.
Bromine produces a similar result, but it is
some time before the effect is observed. Iodine
will also decolorize the solution after some
hours, and produces a brown precipitatCj which
is found to contain iodine.

Haematosine when dry is of a dark red co-
lour and exceedingly hard, having a vitreous
fracture. Its chemical properties in many re-
spects resemble those of fibrine, and albumen
in the coagulated state. Berzelius remarks
that, like fibrine, it contains a fatty matter pe-
culiar to itself which can be separated by ether;
this is one point of resemblance in the opinion
of that chemist. The action of acetic acid on
haematosine is a very striking point of resem-
blance between that body and fibrine; for
when the acid in the concentrated state is al-
lowed to remain in contact with haematosine
for a few hours, we observe that it is converted
into a tremulous brown mass which is more or
less soluble in water, and which during solu-
tion evolves nitrogen gas. The nitric, hydro-
chloric, and sulphuric acids, if diluted with an
equal bulk of water, and digested on haema-
tosine, become coloured yellow and disengage
nitrogen; but they do not dissolve the prin-
ciple even at a boiling heat. The results of
such digestions, however, in the hydrochloric
and sulphuric acids, are soluble in water; but
that which has been digested in nitric acid
remains insoluble.

Potash, soda, and ammonia dissolve haema-
tosine with facility, and it is precipitated from
such solution by the addition of an acid. The
acetic acid acts thus, but re-dissolves the pre-
cipitate if added in excess, as it would albu-
men or fibrine.

Tannin precipitates haematosine from solu-
tion in alkalies.

Tiedemann and Gmelin have observed that
boiling alcohol will dissolve haematosine ; this
is also the case to a considerable extent with
its combinations with several of the acids which
precipitate it. When haematosine is incinerated
and decarbonized, it yields an ash amounting
to 1.3 per cent, of its weight : this, according
to Berzelius, is composed of the following sub-
stances : —

504

HjEMATOSINE.

Caroonate of soda, with traces

of phosphate 0.3

Phosphate of lime 0.1

Caustic lime 0.2

Subphosphate of iron 0.1

Sesqui-oxide of iron 0.5

Carbonic acid and loss 0.1

1.3

The ultimate analysis of haematosine ap-
proaches very nearly to that of fibrine. Mi-
chaelis declares to have found a difference of
ultimate constitution between the colouring
matter of arterial and venous blood : his ana-
lyses are as follows : —

Arterial. Venous.

Nitrogen 1 7.253 1 7.392

Carbon 51.382 53.231

Hydrogen 8.354 7.711

Oxygen 23.011 21.666

It will be observed, on examining these ana-
lyses, that the difference of constitution is so
small that we may reasonably conclude it has
been produced by a difference in manipulation
or some other extraneous cause capable of
modifying the result: indeed, ultimate ana-
lyses of identical substances have, when in the
hands of different chemists, often yielded re-
sults far more discrepant than these, and that
too when each operator stood high as an ana-
lyst. Berzelius, in remarking on these expe-
riments, observes that it is impossible for the
chemist to fix the state of blood whether arterial
or venous; for it will lose its condition with
respect to the colouring matter long before the
chemist can procure its haematosine for analysis.
Thus the venous clot becomes of a bright red
colour when exposed to air, and arterial blood
soon loses its vermilion hue. A great con-
trariety of opinion exists as to the cause of the
red colour of haematosine, some chemists sup-
posing that the iron contained in it takes an
active part in its coloration, while others
maintain that though iron is present it cannot
be considered as the cause of colour. Win-
terl imagined he had discovered the secret
when he formed sulphocyanic acid (blut saure)
by carbonizing blood with carbonate of potash
and precipitated salt of iron with the lixivium —
an experiment quoted by Treviranus ; but we
are unable to detect the sulphocyanic acid in
blood, so this formation of a ferruginous co-
louring matter must not be considered as in
any way assisting in the inquiry, although it
simulates the tint of blood most completely.
Fourcroy asserted that subphosphate of iron
was capable of imparting a red colour to serum,
which is not the case, and went so far as to
declare that the colourless globules of the
chyle contained neutral phosphate of iron,
which, when mixed with the blood, was de-
composed by the alkali present into a sub-
phosphate, which on reaching the lungs be-
came a per-salt and imparted colour to the
fluid. This idea is quite hypothetical, and in
discordance with facts as observed by other
jchemists.

Engelhart's experiments on haematosine tend
to shew that iron is in some way influential
in producing the red colour of the blood. He
showed that, though albumen and fibrine
yielded no iron on incineration, the metal ex-
isted in considerable quantity in hsematosine.
He found that a solution of red particles im-
pregnated with sulphuretted hydrogen became
of a violet colour and then passed to a green,
it being impossible to restore the original red
tint. Chlorine when passed through the solution
bleached it, having previously produced a
green colour; when decolorization was com-
plete, white flocculi were observed to fall,
which on being examined yielded no appre-
ciable ash, while the clear solution gave evi-
dence of iron by the usual reagents. The
white flocculi were supposed by Engelhart to
be the colouring matter changed to white by
the abstraction of its iron. It is evident that
even if the colour of the blood were owing to
some peculiar animal matter and not to iron,
we should still expect decolorization by chlo-
rine ; but yet the change of colour from red to
green which that re-agent produces previous to
decolorizing the solution, renders it probable
that its action is on iron in some form of com-
bination as yet unknown. Rose has shown
that many organic matters interfere with the
action of the tests for iron when present in
solution with that metal, and quotes this to
account for the failures in procuring the re-
actions of iron from the blood in a fluid state.
Some experiments of Berzelius, however, have
proved that the artificial combinations of iron
with albumen which Rose formed, can be pre-
cipitated by ferrocyanate of potassa if they
are previously treated with acetic acid : as this
does not happen with blood, it is very pro-
perly contended that Rose's experiments are
not to be looked upon as an explanation of the
difficulty. In a paper published by Mr.
Brande in the Philosophical Transactions for
1812, that gentleman proposes to consider
haematosine as an animal dye, which like co-
chineal is capable of uniting with metallic
oxides ; thus the oxides of mercury and tin are
active precipitants of this colouring matter,
and woollen clothes previously impregnated
with a solution of bichloride of mercury have
been permanently dyed by steeping them in a
solution of hsematosine. The question as to
whether or not iron be really necessary to the
existence of the red colour of the blood can-
not be considered as determined, and it is
difficult to imagine any line of experimenting
which could afford results sufficiently satis-
factory to settle the point. Mr. Brande's ex-
periments, by which he concluded that hsema-
tosine contained iron in no greater proportion
than fibrine or albumen, would have placed the
matter beyond doubt if other chemists had
confirmed" his observations; but the expe-
riments of Dr. Engelhart published in 1825,
and which have received very general con-
firmation, show that fibrine and albumen
when pure contain no iron, and that the metal
exists in considerable quantity in hasmatosine.
(G.O. Rees.)

BONES OF THE HAND.

505

HAIR. See TEGDMENTARY SYSTEM.

HAND, BONES OF THE, (Human Ana-
tomy.) The hand (^n^manus; Fr. lamain;
Germ, die Hand,) is the inferior segment of
the upper extremity. Its presence is charac-
teristic of man and the Quadrumana.

Although formed on the same general type,
the hand will be found to exhibit many points
of difference from the foot — characters strongly
indicative of the diversity of use for which it
is designed. In examining the skeleton of the
hand, we observe subdivisions analogous to
those which exist in the foot— the carpus cor-
responding to the tarsus, the metacarpus to the
metatarsus, and the phalanges of the ringers in
every way analogous to those of the toes.
Independently of the lightness and mobility
which are such prominent features in the me-
chanism of the hand, when contrasted with
that of the foot, the divergence of the first or
radial finger (the thumb) from the line of
direction of the other four, is peculiarly cha-
racteristic of the hand. Whilst the four fingers,
properly so called, are parallel to the middle
line of the hand, the thumb, when extended,
forms with itan angle of rather more than 45°. To
this position of the thumb is due in the greatest
part the facility of opposing it to one of the
fingers, a movement so necessary in the pre-
hension of minute objects.*

The general form of the hand is oval, the
obtuse extremity corresponding to the tips of
the fingers, the unequal lengths of which oc-
casion the curvature in this situation. On its
posterior surface or dorsum, the hand is convex ;
on its anterior surface or palm, it is concave :
both these surfaces correspond to, and in the
recent state are supported by, the bones of the
carpus and metacarpus.

I. Carpus (Germ, die Handwurzel). The
carpus bears a much less proportion in size to
the whole hand than the tarsus does to the foot;
it forms scarcely more than one-fourth of the
hand. Its outline is oval, the long axis being
transverse : if examined in a hand to which
the ligaments are attached, the carpus will be
found to form the posterior and osseous portion
of an osseo-ligamentous ring, which gives pas-
sage to the tendons of the ringers. It is con-
sequently hollowed from side to side, and is
bounded on each side by a bony ridge, which
gives attachment to the ligament (annular
ligament) which forms the anterior part of the
ring ; on the radial side the ridge is formed by
a process of the os trapezium and of the sca-
phoid ; on the ulnar, where there is a more
prominent ridge, by a process of the unciform
bone, and by the os pisiforme.

Seven bones, arranged in two rows, form
the carpus. The superior row consists of the
os nai-iculare, os lunare, and os cuneiforme,
to which last is articulated a bone, constantly
reckoned as a carpal bone, but which, I con-
ceive, may be more correctly regarded as a
sesamoid bone, the os pisiforme. The second

* See the prefatory observations to the article
FOOT.

or inferior row is formed by the os trapezium,
os trapezoides, os magnum, and os unciforme.

1. Os naviculare (os scaphoideum ; Fr. le
scaphoide; Germ, das Kahnbein). The na-
vicular or scaphoid is the largest of the upper
row, and likewise the most external. Its su-
perior surface is convex, oval, with long axis
transverse, articular, and is adapted to the
outer part of the carpal articular extremity of
the radius. The hollowed surface, to which it
owes its name (boat-like), is directed down-
wards and inwards ; this is likewise articular and
receives the head of the os magnum : con-
tinuous with and to the inner side of this
hollow surface, there is a plane one of a semi-
lunar form, with which the os lunare is articu-
lated. The scaphoid bone articulates with the
trapezium and trapezoides, by a convex surface
directed downwards and outwards. Externally
this bone terminates in a pointed extremity
which receives the external lateral ligament of
the wrist-joint and the annular ligament (tuber-
culum ossis navicularis, s. eminent ia carpi radialis
superior). The anterior and posterior surfaces
of the bone are rough, and give attachment to
the anterior and posterior radio-carpal ligaments.

2. Os lunare, (os semilunare v. lunatum ;
Fr. le semilunaire ; Germ, das Mondbein),
situated between the scaphoid and the cunei-
form bones, it presents four articular surfaces ;
an upper one, convex and somewhat triangular
in its outline, articulated with the radius; an
inferior one, very much hollowed from before
backwards (to the crescentic form of which the
bone owes its name), articulated with the os
magnum; an external surface, plane and
square, adapted to the cuneiform bone ; and,
lastly, an internal surface, by which it articu-
lates with the scaphoid.

3. Os cuneiforme (os triquetrum s. pyra-
midale; Fr. le pyramid-ale; Germ.dasdreiseitige
Bein). This bone terminates the superior
carpal row on the ulnar side ; its upper surface
is partly smooth, encrusted with cartilage in
the recent state, where it is in contact with the
triangular ligament of the wrist-joint, and
partly rough where it gives attachment to liga- A
ments. Externally it articulates with the euueia. y '•' "'

"fewn. bone, and inferiorly with the unciform
by a large and concave suaface. The inner
half of its anterior surface articulates with the
pisiform bone, and the radial half of the same
surface is rough for ligamentous insertion.

The three bones just described, constituting
the superior row of the carpus when united,
present on their superior aspect a convex arti-
cular surface which forms the carpal portion
of the radio-carpal joint, the scaphoid and
lunar being articulated with the radius, while
the cuneiform glides upon the triangular carti-
lage of the wrist.

4. Os pisiforme (from piswn, a pea; Fr.
le pisiforme; Germ, das Erbsenbein). This
little bone projects at the anterior part of the
ulnar extremity of the superior carpal row;
it forms what some anatomists designate
eminentia carpi ulnaris superior, being part of
the bony ridge already referred to on the ulnar
side of the carpus. The prominence produced

506

BONES OF THE HAND.

by this bone is easily felt during life, more
especially during flexion of the wrist-joint.
It is round every where, except posteriorly,
where it presents a flat circular surface, by
which it is articulated with the cuneiform bone.
This bone is intimately connected with and
as it were inclosed in the terminal portion of
the tendon of the flexor carpi ulnaris.

5. Os trapezium (os multangulum majus ;
Fr. le trapeze ; Germ, das grosse vielwinkliche
Bein). This bone is situated at the radial
extremity of the inferior carpal row, having the
scaphoid above it and the metacarpal bone of
the thumb below it. We may describe six
surfaces upon it, four articular and two non-
articular. «. A large articular surface, situated
on the external and inferior aspect of the bone.
This surface is for articulation with the meta-
carpal bone of the thumb : it is somewhat oval
in form, the long axis passing from without
inwards and downwards ; in this direction it is
concave, from before backwards it is convex.
The three remaining articular surfaces are on
the internal and superior aspects of the bone.
6. Internally, a very small plane surface,
adapted to a corresponding one on the radial
side of the carpal extremity of the second
metacarpal bone. c. Above the last described
surface and separated from it merely by a slight
ridge, we find one of a somewhat triangular form
and slightly concave, articulated with the radial
side of the trapezoid. d. Quite on the superior
aspect a small semicircular surface, adapted
to the scaphoid. Of the non-articular surfaces,
one is on the palmar aspect of the bone, and
is easily distinguished by the prominent ridge
or tubercle at its outer part, which gives attach-
ment to the annular ligament, (tuberculum,
eminentia carpi radialis inferior ;) and on the
ulnar side of this ridge a groove in which the
tendon of the flexor carpi radialis glides. The
second non-articula*r surface is on the dorsal
aspect : it is more extensive than the last,
rough and tuberculated, affording insertion to
ligaments.

6. Os trapezoides (os multangulum minus;
Fr. le trapezoide; Germ, das Kleine viel-
winkliche Bein), This is the second bone of
the inferior carpal row ; it has the os trapezium
on its radial and the os magnum on its ulnar
side, the scaphoid above and the second meta-
carpal bone below it. We describe four articular
surfaces and two non-articular, a. The inferior
one the largest, quadrilateral, much narrower
in front than behind, convex from side to side,
slightly concave from before backwards, is
entirely devoted to articulation with the second
metacarpal bone. b. On the radial side, a
slightly convex surface for the trapezium.
c. Superiorly a quadrilateral concave surface
for articulation with the scaphoid, d. On the
ulnar side a very small surface, adapted to a
corresponding one-, on the radial side of the os
magnum. The palmar surface is non-articular,
five-sided, slightly excavated, and rough from
the insertion of ligaments. The dorsal surface,
also non- articular, is of greater extent, con-
vex, and likewise rough.

7. Os nwgnum (os capitatum ; Fr. le grand

os ; Germ, das Kopfbem). This bone is, as
its name implies, principally characterized by
its excess in size over the other carpal bones,
and from the number of bones with which it is
connected, it may be regarded as the key-bone
of the carpus. Superiorly it is in the form of
a rounded head (capitulum}, flattened on the
ulnar side, where it articulates with the unciform
bone. The superior prominent portion of this
head is received into the excavation of the lunar
bone, and by its radial side it articulates with
the inferior hollow surface of the scaphoid.
The inferior portion of the bone is cuboid, and
has been called the body ; it is rough and con-
vex on its palmar surface, also rough but
irregular on its dorsal, both these surfaces
affording insertion to numerous ligaments.
Inferiorly we notice an extensive articular sur-
face, which is adapted in the centre to the
third metacarpal bone, on the radial side to the
second, and by a very small portion on the
ulnar side to the fourth metacarpal bone. On
the ulnar side of its inferior portion it articu-
lates a second time with the os unciforme
by a small circular articular surface, the cir-
cumference of which nearly equals that of the
flat surface of a split pea. Lastly, on its radial
side it articulates with the trapezoid bone.
Thus the os magnum articulates with seven
bones; three metacarpal bones, two carpal
bones in the inferior row, and two in the supe-
rior row.

8. Os unciforme (from uncus, a hook, os ha-
matum ; Fr. 'l'os crochu ou unciforme ; Germ.
das Hakenbein, oder Keilformiger Knochen).
This bone has received its name from that
which allows of its being easily distinguished
from all the carpal bones, — namely, the hooked
process, which projects from the radial edge of
its palmar surface. This process constitutes a
considerable prominence on the ulnar side of
the carpus (eminentia carpi ulnaris inferior),
and affords insertion to the annular ligament.
Its concavity looks towards the radial side of
the carpus ; the remainder of the palmar sur-
face is rough for ligamentous insertion. The
dorsal surface is likewise rough, convex, and
of considerable extent. This bone articulates
inferiorly with the fourth and fifth metacarpal
bones, on its radial side with the os magnum, and
on its superior surface with the cuneiform bone.

Structure of the carpal bones. — These bones
are chiefly composed of the reticular osseous
tissue, to which their extreme lightness is attri-
butable, the surface being invested by a thin
layer of compact texture, in this respect per-
fectly resembling the bones of the tarsus.

Developement . — The carpal bones are very
late in their developement ; at birth they are
completely cartilaginous. According to Cru-
veilhier, each bone is developed by a single
point of ossification. The os magnum and os
unciforme are the first in which the ossific pro-
cess commences, about the end of the first
year; between the third and fourth years it
begins in the cuneiform, a year later in the
trapezium and lunar, and between the eighth
and ninth years in the scaphoid and trapezoid
bones. The ossification of the pisiform does

BONES OF THE HAND.

507

not begin till between the twelfth and fifteenth
years, and Cruveilhier states that of all the
bones of the skeleton it is the last in which the
process of ossification is completed.

II. Metacarpus (Germ, die Mittelhand).
Five bones constitute the metacarpus, the four
internal ones being parallel to each other, the
external one diverging outwards at an acute
angle with the middle line of the hand. These
bones vary in length from about two inches and
a half to one inch six-eighths. They articulate
inferiorly with the superior or metacarpal pha-
langes, and superiorly with the carpus.

Each metacarpal bone presents two extremi-
ties, and a shaft or body between them. The
superior or carpal extremity is expanded and
wedge-shaped, the broader part being towards
the dorsal aspect. Three articular surfaces
exist on each ; one, the most extensive, on the
superior or carpal surface, for articulation with
a carpal bone ; the other two on the radial and
ulnar surfaces, adapted to the adjacent meta-
carpal bone or to a carpal bone. The palmar
and dorsal surfaces are rough and irregular,
and afford insertion to the ligaments \vhich
strengthen the carpo-metacarpal jointsv^The
interior or digital extremity is in the form of a
rounded head, flattened on each side, where
we notice a depression, and behind it a tubercle
which affords insertion to the lateral ligament
of the joint. The smooth articular surface of
the head extends further upon the palmar sur-
face of the bone than upon its dorsal surface,
or, as in the case of the metatarsal bones, more
on the side of flexion than on that of extension.
The shaft or body is prismatic and slightly
curved, so as to present a concavity towards the
palmar surface, and a convexity to the dorsal.

The metacarpal bones are numbered from
without inwards. The first, or that of the
thumb, is the shortest of all and likewise the
thickest. Its carpal extremity will likewise
serve to distinguish this bone; it wants the
cuneiform shape, and is rather wider on its
palmar than its dorsal surface. It has no arti-
cular facets on its sides, being articulated with
the trapezium alone by means of a surface
which is concave from before backwards, and
Convex from side to side ; the body of this bone
is flatter on its palmar and dorsal surfaces than
any of the others.

The second metacarpal bone is the longest ;
it, however, exceeds the third by a very slight
difference. It is further distinguished from the
third by the diminutive size of the articular
facet on the radial side of its carpal extremity.

The third metacarpal bone, though shorter
than the second, is manifestly thicker and
stronger; this excess of developement being
attributable to its affording insertion to one of
the most powerful muscles of the hand, —
namely, the adductor pollicis.

The fourth and fifth metacarpal bones are
shorter and in every way smaller than the pre-
ceding ones. The fifth is shorter and somewhat
thicker than the fourth : it has no articular facet
on the ulnar side of its carpal extremity, but
presents a prominent tubercle in that situation
for the insertion of the extensor carpi ulnaris.

The structure of the metacarpal bones is the
same as that of the long bones in general.

Developement. — There are two points of
ossification for each metacarpal bone, one for
the body and the carpal extremity, the other
for the digital extremity. The first metacarpal
bone, however, according to Cruveilhier, offers
an exception to this, inasmuch as its carpal
extremity is developed from a point of ossifica-
tion distinct from that of the body. In some
instances there are three points of ossification
for each metacarpal bone. The bodies of the
metacarpal bones are completely ossified at
birth. Between the second and third years
appear the points for the inferior extremity in
the four inner bones and the superior extremity
in the first, but the complete fusion of the
extremities with the shafts does not take place
till near the twentieth year.

III. Fingers ( digit i; Fr. les doi»ts ; Germ.
die Finger). The fingers differ strikingly from
the toes as regards their length, to which, in-
deed, is due their greater mobility. They are
numbered in proceeding from the radial to the
ulnar side of the hand. All except the thumb
are composed of three phalanges, the superior
or metacarpal, the middle, ana1 the inferior or
lingual: in the thumb the middle phalanx is
absent. The fingers differ considerably in length ;
the thumb is by far the shortest, and the middle
finger is the longest. Next in length is the
ring finger, then the index, and last and least
the little finger.

The metacarpal phalanges have the following
general characters : — 1st, a body slightly con-
cave from above downwards on the palmar
surface, and convex on the dorsal ; 2d, a supe-
rior or metacarpal extremity more expanded
than the inferior, hollowed into an articular
surface for the head of the metacarpal bone ;
and 3d, an inferior extremity, having a pulley-
like surface for articulation with the middle
phalanx. The metacarpal phalanges are the
longest.

The middle phalanges present the same cha-
racters as the preceding as regards the body.
The superior extremity has a pulley-like articu-
lar surface, convex transversely; that of the
inferior extremity being concave in the same
direction.

The ungual phalanges are readily distin-
guished by the inferior or ungual extremity,
which is rough, non-articular, horseshoe-shaped,
with the convexity directed downwards. It is
this part of the bone which supports the nail.
The superior extremity is articulated with the
middle phalanx by a pulley-like surface, con-
cave transversely. The ungual phalanx of the
thumb is considerably larger than that of any
of the other fingers.

In point of structure and developement the
phalanges scarcely differ from the metacarpal
bones. There are two points of ossification,
one for the body and inferior extremity, the
other for the superior extremity. This last is
late in making its appearance, not until between
the third and seventh year, while the ossifica-
tion of the body commences at an early period
of intra-uterine life.

A

508

BONES OF THE HAND.

Although the perfect prehensile hand is pecu-
liar to man and the Quadrumana, the inferior
segment of the anterior extremity will be found
to possess many interesting analogies through-
out the mammiferous series. On this point we
refer to the articles OSSEOUS SYSTEM (Comp.
Anat.) and SKELETON.

JOINTS OF THE HAND.

Joints of the carpus. — The bones consti-
tuting each row of the carpus are firmly con-
nected by strong ligaments, so that their com-
bined surfaces form one extended surface
adapted to the radius, or to the metacarpus, or
to each other. Thus the union of the superior
articular surfaces of the upper carpal row con-
stitutes the convex surface that contributes to
the formation of the wrist-joint, whilst the
united inferior articular surfaces of the same
row are adapted to the united superior surfaces
of the inferior carpal row. Again, the inferior
articular surfaces of this last row enter into the
formation of the carpo-metacarpal joints.

The several articulations of each row are
strengthened by two sets of ligaments, one on
the palmar, the other on the dorsal surface of
the joints, palmar and dorsal ligaments ; they
extend transversely from one bone to the other.
The palmar ligaments are considerably stronger
than the dorsal. The synovial membranes
which exist in these small articulations are
merely offsets from the large synovial mem-
brane which is interposed between the two
rows of the carpus.

In the articulation between the scaphoid and
lunar bones, as well as in that between the
lunar and cuneiform, we observe a remarkable
fibro-cartilaginous lamina interposed in the
whole extent of each articulation from before
backwards, although not extending over the
entire articular surfaces. These laminae are
readily seen on opening the radio-carpal joint
in the interval between the bones above men-
tioned; they are attached to the palmar and
dorsal ligaments by their anterior and posterior
extremities. When dissected out they will be
found to be wedge-shaped, the thick edge being
directed towards the wrist-joint, and adherent
to the synovial membrane of that joint. These
laminae are described by most anatomists as
ligaments, under the name of interosseous liga-
ments. Of their fibro-cartilaginous nature,
however, I have no doubt from repeated and
careful examinations; they may therefore be
more correctly denominated interosseous fibro-
cartilages. Feeble interosseous ligaments exist
on either side of the os magnum between it
and the unciform on one side, and the trapezoid
on the other; they are best seen when these
bones are torn from each other.

Articulation of the two rows of carpal bones
to each other. — The superior articular surfaces
of the four bones composing the inferior carpal
row are adapted to the inferior articular surfaces
of the scaphoid, lunar, and cuneiform bones.
The head of the os magnurn and the superior
articular surface of the unciform bone form a
prominent convexity, which is received into a
deep concavity formed on the ulnar side by the
cuneiform bone, on the radial side by the

scaphoid, and in the centre by the lunar bone;
whilst external to the projection of the os mag-
num, a superficial oblong concavity receives the
convexity on the inferior and outer surface of
the scaphoid. Thus the line of this articulation
has somewhat of the course of the roman S
placed horizontally, OB. That part of the arti-
culation which is to the ulnar side, then, par-
takes more of the nature of enarthrodia or ball
and socket joint, while that to the radial side
is arthrodia with almost plane surfaces.

This articulation is strengthened in front by
an anterior or palmar ligament which is of
considerable strength and thickness. Most of
the fibres of this ligament are attached inferiorly
to the palmar surface of the os magnum,
whence they diverge to be inserted into the
scaphoid, lunar, and cuneiform bones; some
few fibres extend from the trapezoid and trape-
zium to the scaphoid, and from the unciform
to the cuneiform. Behind we find a dorsal
ligament, also strong, although much less so
than the palmar. This ligament extends
obliquely from the bones of the first row to
those of the second, but is stronger on the ulnar
than on the radial side. The extent and con-
nexions of both these ligaments are best seen
when the joint is opened, by cutting through
the dorsal ligament to view the palmar, and
vice versa. The ligaments called lateral by
some anatomists are merely the continuation of
the lateral ligaments of the wrist-joint; nor do
those described by Cruveilhier under the name
of glenoid Ligaments deserve to be separated
from the anterior and posterior, of which they
constitute that portion most intimately connected
with the anterior and posterior notches of the
hollow cavity in which the head of the os mag-
num is lodged.

In opening this joint in the manner already
described, it will be seen how extensive is its
synovial membrane. It extends some distance
on the palmar and dorsal surfaces of the neck
of the os magnum, and sends two processes
between the bones of the first row (between
the scaphoid and lunar, and the lunar and
cuneiform), and three processes between those
of the second row, (one on each side of the
os magnum,) and one between the trapezium
and trapezoid.

Motions of the carpal articulations. — An
examination of the dissected carpus will at
once show how limited are the motions between
any two of the carpal bones of each row. The
movement of one row upon the other, however,
is more extensive, but only in the direction of
flexion and extension, the former being con-
siderably greater in consequence of the less
resistance of the dorsal ligaments. Solidity
and strength, a power of resistance to violence
which might easily occasion fracture, were the
carpus one solid bone, are gained by the num-
ber of small bones of which it is composed,
the arthrodial form of its articulations, and the
strong ligaments by which the motions of these
joints are restricted.

Articulation of the pisiform bone. — The
pisiform bone is so little connected with the
mechanism of the carpus that its articulation

BONES OF THE HAND.

509

with the cuneiform bone demands a separate
consideration. A plane oval surface on the
posterior part of the pisiform is articulated
with a corresponding one on the palmar aspect
of- the cuneiform, and several strong ligaments
strengthen the joint. Two lateral ligaments
pass from the pisiform to the cuneiform bone,
the internal, which is also anterior, being of
considerable strength. This bone is further
connected to the unciform by strong ligament-
ous fibres; and a strong bundle, which bears the
same relation to the tendon of the flexor carpi
ulnaris as the ligamentum patellae does to the
tendon of the rectus fernoris, extends to the
carpal extremity of the fifth metacarpal bone.
This joint is provided with a loose synovial
membrane; its motions are those of gliding
in the directions of the axis of the articular
surfaces.

Carpo-metacarpal joints. — These are very
strong articulations, and, with the exception of
the first and fifth, enjoy a very limited extent
of motion. The four internal ones are nearly
planiform arthrodise, restricted on the palmar
and dorsal surfaces by strong and short liga-
ments (palmar and dorsal ligaments), the latter
being much better developed. The second
metacarpal bone is articulated with the trapezoid
in an extremely firm manner: its palmar liga-
ment extends from the extremity of the meta-
carpal bone to the trapezium internal to the
ridge, and covered by the tendon of the radial
flexor of the wrist. There are three dorsal
ligaments, an external attached to the trapezium,
and an internal to the os magnum. These two
ligaments are oblique in their direction ; the
third or middle one is vertical and attached to
the trapezoid. The third metacarpal bone is arti-
culated with the os magnum : here we find
three strong palmar ligaments, an external one
which extends obliquely outwards to the trape-
zium, an internal one which passes in front of
the carpal extremity of the fourth metacarpal
bone, adhering to it, and inserted into the
unciform and the fifth metacarpal bone, and a
middle one which passes vertically to the os
magnum. This joint has two dorsal ligaments,
both inserted into the os magnum. The fourth
metacarpal bone is articulated with the radial
portion of the inferior articular surface, and
with a very small portion of the os magnum ;
it has a single palmar and dorsal ligament.
The fifth metacarpal bone is articulated with
the outer part of the inferior surface of the
unciform; this surface is convex transversely
and concave from before backwards, while that
on the metacarpal bone is convex from before
backwards and concave transversely. The
proper ligaments of this joint are very feeble,
being merely a few fibres attached to the ante-
rior and posterior surfaces of the synovial mem-
brane. The joint, however, is protected in
front by the prominence of the unciform pro-
cess, which descends a little below the line of
the articulation, and limits the forward motion
of the carpal extremity of the bone ; and pos-
teriorly it is strengthened by the tendon of the
extensor carpi ulnaris, while its motion ulnad
is restricted by the strong internal palmar liga-

ment of the third metacarpal bone, which we
have already described as passing from that
bone to the fifth metacarpal and the unciform
bones. The fifth carpo-metacarpal articulation
approaches in many particulars to the first; it
has a greater latitude of motion than the three
immediately preceding it, and its articular sur-
faces very much resemble those of the first.

Besides the palmar and dorsal ligaments
already described, these metarcarpal bones are
very firmly connected to each other by short
but strong ligaments, extending transversely
from one to the other on the palmar and dorsal
aspects.

A common synovial membrane extends
throughout the four joints above described ;
this synovial membrane is continuous with that
between the two rows of carpal bones.

The digital extremities of the four inner
metacarpal bones are connected by their trans-
verse ligaments situated at the palmar surface
and extending from one to the other.

Carpo-metacarpal joints of the thumb. — The
main feature by which this articulation is dis-
tinguished from the other carpo-metacarpal
joints is its great mobility. It is an arthrodia,
and in many particulars resembles very much
the sterno-clavicular joint. The trapezium
presents a surface concave from within out-
wards, and convex from before backwards,
that on the metacarpal bone being convex in
the transverse, and concave in the antero-pos-
terior direction.

The ligamentous apparatus of this joint has
very much the appearance of the capsular
ligament of an enarthrosis, and has indeed
been described as such by many anatomists ;
but on a careful examination it will be found
to consist of separate bundles of ligament
placed at those situations in which the greatest
tendency to displacement exists in the various
motions of the joint. Four principal bundles
may be described : one very thick and strong,
situated at the posterior and outer part of the
joint, (lig. dorsale, Weitbr.) extending from
the metacarpal bone to a prominent tubercle
on the outer part of the dorsal surface of the
trapezium; this ligament limits flexion of the
joint. A second ligament is situated directly
in front of the joint, (lig. palmare, Weitbr.)
is inserted into the trapezium immediately
internal to its prominence; extension is limited
by this ligament. The third and fourth bundles
(Lig. laterale ext. et int. Weitbr.) are situ-
ated on the radial and ulnar sides of the joint :
they are less distinct as well as less strong than
those last described. That on the ulnar side
is considerably the stronger; it limits abduc-
tion of the thumb, whilst that on the radial
side limits adduction.

The synovial membrane of this joint is lax ;
it is perfectly distinct from the general syno-
vial membrane of the other carpo-metacarpal
articulations.

Motions of the carpo-metacarpal joints. —
In the second, third, and fourth joints the
motions are limited to a very slight, and during
life scarcely appreciable gliding forwards or
backwards: the strong transverse ligaments,

510

ABNORMAL CONDITIONS OF THE HAND.

as well as the close manner in which the carpal
extremities of the metacarpal bones are im-
pacted together, render lateral motion impos-
sible ; in the fifth joint the forward or back-
ward motion is somewhat more extensive, but
this joint is equally limited with the others in
lateral movement.

The carpo-metacarpal joint of the thumb
enjoys motion forwards, backwards, inwards,
and outwards, producing the movements of
flexion and extension, abduction and ad-
duction. The power of opposing the thumb
to any of the fingers is due to the oblique
direction of flexion in this joint : the bone
moves forwards and inwards, passing through
a line which would be concave inwards. This
is by far the most extensive motion of the
thumb, and it is by an excess of this motion
that the dislocation of the metacarpal bone
backwards is generally occasioned. Cru veil-
bier observes that the weakness of the posterior
ligament favours the occurrence of this lux-
ation. I cannot, however, admit the weakness
of this ligament ; on the contrary, it appears
to me to be the strongest of all the ligaments
of this joint ; which opinion, I find, is that of
the accurate Weitbrecht.

The motion of adduction is, on the other
hand, the most limited, in consequence of the
proximity of the second metacarpal bone ; that
of abduction is very extensive, and when car-
ried too far may occasion luxation inwards.

JOINTS OF THE FINGERS.

1. Metacarpo-phalangeal joints. — The first
phalanges are articulated by an oval concave
surface, with the rounded oblong heads of the
inferior extremities of the metacarpal bones :
it is remarkable that the long axis of the oval
concavity of the phalanx has a transverse di-
rection, while the long axis of the head of the
metacarpal bone is directed from before back-
wards, and consequently at right angles with
the former ; whence the great extent of lateral
motion enjoyed by these joints.

Each of these joints is strengthened by two
lateral ligaments, of considerable strength,
inserted into the tubercle behind the depression
on each side of the head of the metacarpal
bone ; the point of insertion into the phalanx
is anterior to this, and consequently the direc-
tion of the lateral ligaments is downwards and
forwards; as they descend, these ligaments
spread out, and their anterior fibres become
identified with the anterior ligament.

A third ligament, the anterior ligament, or
glenoid ligament of Cruveilhier, seems des-
tined more to increase the extent of the pha-
langeal articular concavity anteriorly, than to
maintain the integrity of the joint or limit its
motions. This ligament is, as Bichat expresses
it, a thick and dense fibrous bundle, in shape
half a ring, placed in front of the palmar sur-
face of the head of the metacarpal bone, com-
posed of transverse fibres which adhere in-
feriorly to the anterior edge of the concavity
on the phalanx, and on each side are identified
with the lateral ligaments and the transverse
ligaments by which the metacarpal bones are
connected. If the ligaments and synovial

membrane of this joint be cut all round close
to their attachment to the head of the meta-
carpal bone, and that bone be removed, the
synovial capsule and ligaments remaining at-
tached to the phalanx, a very clear idea of the
relative positions of the ligaments may be
formed. The synovial membrane will then
appear protected on three sides by ligament ;
on the radial and ulnar side by the lateral
ligaments, and in front the anterior ligaments,
whilst posteriorly it is unprotected save by the
sheath of the extensor tendon.

In the metacarpo-phalangeal articulation of
the thumb two sesarnoid bones, developed in
the substance of the anterior ligament, protect
the joint in front.

2. Phalangcal joints. — These joints are all
ginglymoid, the articular surfaces being pul-
ley-like ; they are provided with lateral liga-
ments similar to those of the metacarpo-pha-
langeal joints, and also with anterior ligaments
similarly disposed.

Motions of the joints of the fingers. — In
the phalangeal joints these motions are only
flexion and extension; the former are con-
siderably more extensive, and are favoured by
the inferior insertion of the lateral ligaments
being on a plane anterior to their superior
insertion. In addition to flexion and exten-
sion the metacarpo-phalangeal joints enjoy con-
siderable lateral motion, which is due to the
glenoid form of the phalangeal articular sur-
face, and to the enarthrodial form which the
joint derives from the extension of that arti-
cular surface by the anterior ligament.

(R. B. Todd.)

HAND,ABNORMAL CONDITIONS OF
THE. Deviations from the normal condition
of the different structures which enter into the
composition of the hand are very numerous,
and may be classed into those which are the
result of, first, accident; second, disease;
third, congenital malformation.

I. ABNORMAL CONDITIONS, THE RESULT OF
ACCIDENT.

Fractures and luxations. — Simple frac-
tures of the bones of the hand are seldom
followed by any notable deformity ; but lux-
ations of these bones require from us some
attention here.

Luxation of the bones of the carpus. — The
bones of the carpus are united to each other so
solidly, and their movements seem so limited,
that, without experience, we should be dis-
posed to pronounce luxation of any of these
bones impossible ; nevertheless, the head of
the os magnum may be dislocated from the
cavity formed for it by the scaphoid and semi-
lunar bones. The first range of the bones of
the carpus is articulated with the bones of the
second range in such a manner that slight
gliding movements of flexion and extension of
the hand are permitted, which augment a little
the movements of flexion and extension of
the hand upon the forearm, and add some-
what, as Cruveilhier says, to the grace of the
movements of this portion of the upper ex-

ABNORMAL CONDITIONS OF THE HAND.

511

tremity. In flexion, the head of the os mag-
num, which is somewhat inclined backwards,
raises up the thin capsule which surrounds its
articulation, and, if this movement be carried
very far, the capsule and accessory fibres which
support the bone posteriorly are broken, and
the os magnum escapes from the cavity in which
it is naturally placed ; the dislocation cannot
be called complete, yet the os magnum passes
somewhat the level of the posterior surface of
the other bones of the carpus. The accident
is more common in women than in men, no
doubt because the ligaments are weaker and
the bones enjoy greater motion in the former
than in the latter ; the luxation backwards of
the os magnum, the only one which can occur,
is always the result of a forced and violent
flexion of the wrist, such, for example, as a
fall on the back of the hand would produce.

We recognize the luxation of the os mag-
num by the history of the accident, and by the
deformity produced. We perceive a hard cir-
cumscribed tumour which has suddenly ap-
peared on the back of the hand in the situation
which corresponds to the head of the bone.
This tumour becomes more prominent when
the hand is flexed, and diminishes when it is
extended ; we can make it disappear entirely
by a slight compression. This luxation causes
but little inconvenience, but the head of the
os magnum always remains more salient when
the hand is flexed, and forms a tumour more
or less marked according to the extent of the
displacement.

We can easily reduce this luxation by ex-
tending the hand, or by exercising a slight
pressure on the head of the os magnum ; but,
although it is easy to make the bone resume
its position in the cavity formed for it by the
scaphoid and semilunar bones, it is very dif-
ficult to maintain it there, and the inconve-
nience and deformity resulting from the luxation
are so trivial that few persons will submit with
patience to the means usually recommended.

Luxation of the bones of the metacarpus. —
Luxation of the metacarpal bone of the thumb.
The carpal head of the metacarpal bone of the
thumb, notwithstanding the range of motion it
enjoys, is rarely dislocated. Sir A. Cooper, in
his extensive experience, has seen but one spe-
cies of this accident, viz. luxation of the meta-
carpal bone of the thumb upon the os trapezium,
inwards. " In the cases I have seen of this
accident," says Sir Astley, " the metacarpal
bone has been thrown inwards between the tra-
pezium and the root of the metacarpal bone of
the fore-finger ; it forms a protuberance towards
the palm of the hand; the thumb is bent back-
wards, and cannot be brought towards the little
finger : considerable pain and swelling are pro-
duced by this accident."

Luxation of the carpal head of the meta-
carpal bone of the thumb backwards. Some
surgeons seem to doubt that the metacarpal
bone of the thumb is capable of being dis-
located in any other direction than that in-
wards; but the following case is given on the
highly respectable authority of the experienced
Boyer. Madame De la P luxated the

metacarpal bone of her left thumb backwards
on the dorsum of the trapezium by falling on
the external or radial border of her hand ; the
luxation was at first mistaken. When Boyer
saw it six months after the accident, the su-
perior extremity of the metacarpal bone of the
thumb formed posteriorly a very remarkable
prominence on the trapezium, and this bone
and the phalanges of the thumb were inclined
towards the palm of the hand. On pressing
posteriorly on the prominence formed by the
superior extremity of the dislocated bone, it
could be made to resume its natural place and
the prominence disappeared; so long as the
pressure was continued, the bone retained its
place and the thumb enjoyed its natural powers
of flexion and extension ; but as soon as the
pressure was remitted, the bone became dis-
placed anew, and the movements of the thumb
impossible. The lady was unwilling to sub-
mit to any treatment, and the condition of the
joint remained unaltered. These luxations of
the metacarpal bone of the thumb, whether
backwards or inwards, must be rare, as the
causes which are calculated to produce them
must act through the first phalanx of the thumb,
which, it is manifest, will be much more dis-
posed to yield than the metacarpal bone.

Luxation of the phalanges of the fingers. —
The first phalanx of the thumb as well as the
first phalanx of any of the fingers may be
luxated backwards ; the luxation forwards of
the phalanx is very rare and perhaps impossible,
except in the index finger and the thumb.

The mutual support which the first pha-
langes of the fingers afford each other laterally,
and the strength of the lateral ligaments render
the luxation outwards or inwards very difficult.
Luxations of thejirst phalanx of the thumb
from the metacarpal bone. The first phalanx
of the thumb may be luxated forwards to the
palmar surface of the metacarpal bone, but
this form of luxation is very rare, while the
luxation of the same phalanx on the dorsum
of the metacarpal bone is the most common
and important displacement of any to which
the bones of the hand are liable. We shall
therefore consider this accident in detail.

In some persons the first phalanx of the
thumb can at will be dislocated backwards,
solely by the contraction of the muscles. The
displacement produced by accident, however,
is much more extensive than this, which may
be termed the voluntary luxation. When the
first phalanx of the thumb is in a state of
extreme extension, accident may dislocate it
on the dorsum of the metacarpal bone. The
signs of the injury are so evident that mistake
appears impossible; the first phalanx is thrown
back as if pulled by its two extensors, and
forms nearly a right angle with its metacarpal
bone (jig. 226) ; the head of the latter forms
a remarkable tumour at the anterior part
or palmar aspect of the articulation, while
a prominence behind points out the situation
of the base of the first phalanx : the last or
distal phalanx is (in recent cases) flexed, and it
soon becomes difficult or impossible to extend
it, or to flex the first phalanx.

512

ABNORMAL CONDITIONS OF THE HAND.

Fig. 226.

Luxation of the first phalanx of the thumb an the back
of the metacarpal bone.

Anatomical characters of this accident. Op-
portunities of ascertaining by dissection the
actual condition of the parts when luxation
backwards of the first phalanx of the thumb
has recently happened, of course do not occur,
but from the dissection of old unreduced in-
juries of this kind,* and from experiments on
the dead subject, we are led to infer that the
immediate effects of the injury are, extensive
laceration of the anterior part of the synovial
membrane, and of one or both the lateral liga-
ments, while the posterior portion of the cap-
sule remains entire ; the base of the first pha-
lanx is dragged to a considerable extent upon
the dorsum of the metacarpal bone, elevating
with it the tendons of the extensor primi and
secundi internodii pollicis ; the tendon of the
flexor pollicis longus is carried inwards and
under the head of the metacarpal bone. As the
extensor ossis metarcarpi and opponens pollicis
are not attached to the first phalanx, they are
little affected by the luxation, but the con-
dition of the three remaining muscles which
are inserted into the base of the first phalanx
requires consideration. These short muscles
are the abductor pollicis, the flexor pollicis
brevis, and the adductor pollicis.

When the dislocation backwards of the first
phalanx of the thumb has occurred, the large
head of the metacarpal bone is at the same
time thrown inwards towards the palm, and
having forced its way between the two origins
of the flexor pollicis brevis, the shaft of this
bone, which is comparatively much narrower
than the head, becomes tightly embraced by
the two fleshy columns of the muscle. This
is a state of things which should be taken into
account when the obstacles to the reduction of
this dislocation are considered, nor should it
be forgotten that the direction and relative
position of the points of attachment of all the
muscles concerned must be altogether changed
when the complete luxation has occurred;
their origins and insertions are more than na-
turally approximated, and the line of direction
of their action is thrown much behind the

* See London Medical Gazette foi Oct. 14, 1837,
J. A. Lawrie, Glasgow.

longitudinal axis of the metacarpal bone ; the
tendons of the extensor primi and secundi
internodii, and of the flexor pollicis longus are
of course carried by the dislocated bone behind
their usual line of action; hence the action of
all these muscles, after the luxation has oc-
curred, becomes materially altered, their con-
traction will no longer be resisted by the lateral
and capsnlar ligaments, and the bone will
be drawn upwards and backwards by them,
a considerable distance on the dorsum of
the metacarpal bone (Jig. 226). The flexors
have their direction so altered and so thrown
behind the longitudiual axis of the metacarpal
bone of the thumb, that they now no longer
act as flexors of the first phalanx to approxi-
mate it to the palm ; on the contrary, they now
have become extensors of the dislocated pha-
lanx, and tend much by their contraction to
increase the deformity.*

This dislocation is difficult to reduce, par-
ticularly if the nature of the accident have not
been speedily recognized. Various causes have
been assigned for the opposition to the return
of the bone ; some think with the late Mr. Hey
of Leeds, that a transverse section of the head
of the metacarpal bone presents in its outline
somewhat of a cuneiform figure; and that,
in consequence of the narrowest part of the
wedge being thus placed anteriorly, it can
easily under the influence of accident glide
towards the palm by passing between the
lateral ligaments which remain unbroken, and
resist all return of the bone backwards to its
original situation. Others imagine that the
interposition of the anterior ligament and
sesamoid bone attached to it between the arti-
cular surfaces constitutes the principal ob-
stacles to the reduction of this luxation. Again
it has been asserted that the tendon of the
flexor longus pollicis has been twisted spirally
under the metacarpal bone, while some with
more appearance of truth have supposed that
the muscles are the principal sources of re-
sistance. The learned author of the First Lines
of Surgery has expressed his opinion that the
return of the dislocated phalanx to its place is
opposed by a combination of causes, viz. —
the cuneiform shape of the bone and the re-
sistance of the lateral ligaments, as suggested
by Hey, the force of the muscles, and, lastly,
he adds, because the surface for the applica-
tion of the extending means is very limited.
To most of these observations we have reason
to object, particularly to the last, because we
believe that all the force which it is justifiable
to use may be easily applied ; and we should

* In the experiments made by my colleague Mr.
Mayne and myself on the dead subject, when we
forcibly dislocated the first phalanx backwards, we
found the anterior part of the synovial membrane
and the external lateral ligament torn across ; the
first phalanx was placed as inyzj/. 226. We found the
head of the metacarpal bone driven between the two
heads of the flexor pollicis brevis in such a way,
that the external head of the muscle was placed
upon the outside of the shaft of the bone in com-
pany with the abductor pollicis, while the internal
was situated at the inside of it, along with the ad-
ductor and long flexor tendon.

ABNORMAL CONDITIONS OF THE HAND.

513

ever keep in mind a case given on the authority
of Mr. Hey, who informs us that the celebrated
Mr. Bloomfield reported to his class of pupils
at St. George's Hospital, London, that he knew
a surgeon increase the force of extension to
such a degree in attempting reduction of this
dislocation, that he tore off the thumb at the
second joint.

The idea that a transverse section of the head
of the metacarpal bone presents an outline of a
cuneiform figure with the narrowest part of the
wedge towards the palm, or forwards, was finst
advanced by Mr. Hey, and has subsequently
been adopted with too little reflection by many
writers : for our part we do not think that the
head of the metacarpal bone does present this
form assigned to it by Hey. But even al-
though it be conceded that it has occasionally
a form which would answer to the description
given by Mr. Hey, and that its cuneiform
figure would facilitate its gliding between the
lateral ligaments and forbid its return, surely
such an obstacle to the return of the bone
would suppose a state of integrity of both
lateral ligaments. In our experiments on the
dead subject, we found one of these lateral
ligaments invariably torn whenever a complete
luxation was effected ; but with the theory of
Hey, which seems to us quite unsupported by
the normal anatomy of the bone or the anatomy
of the accident, how can we reconcile the
observation, that when the first phalanx of the
thumb is dislocated to the palmar instead of
the dorsal aspect of the metacarpal bone, equal
difficulty of reducing the luxation has been
experienced by very eminent surgeons ' For
example, Velpeau says, " we have seen but
once the first phalanx of the thumb pass in
front of the first metacarpal bone. The sub-
ject of this accident was a woman aged forty-
five years ; the bone had been out for three
days, there was no inflammation." I thought,
says Velpeau, u that it was owing to some want
of skill in myself that I could not succeed in
reducing the luxation ; but M. Professor Bou-
gon also made fruitless efforts to effect it;
finally, M. Roux, with his well-known address
and ingenuity, was not more successful, and
the bone remained ever afterwards unre-
duced."*

Upon the whole it would appear to us that
in the case of the dislocation of the first pha-
lanx of the thumb on the dorsum of the meta-
carpal bone, the cause of the difficulty we ex-
perience in reducing it will not be found either
in the mechanical resistance of the lateral liga-
ments or in the interposition of muscular or
fibrous parts between the extremities of the
dislocated bones, but that, whether the luxa-
tion be the common one backwards or the
more unusual one forwards, t\\evital contraction
of numerous muscles on a small and yielding
bone (whose ligaments have been lacerated)
will be the principal opposing force we have to
contend with. Most of these muscles will be
found to be favourably circumstanced for the

* Velpeau, Traite d' Anatomic des Regions,
torn. i. p. 475, edit. 1825.

VOL. II.

opposition, for they are either inserted into or
attached very close to the bones of the first
phalanx of the thumb : they are six in number ;
some of them are of considerable length, and
the aggregate force of both long and short
muscles constitutes a very powerful means of
maintaining displaced the first phalanx of the
thumb ; nor should it be forgotten, in estimat-
ing their force, that the very large supply of blood-
vessels and nerves which these muscles receive,
must add much more to the energy of their
contraction than the size and number of their
composing fibres would lead us to suppose.

If such a view of the abnormal condition
of the different structures which compose this
articulation be correct, we should derive from
it the important practical precept, that when
we have one of those difficult cases to contend
with, our first effort should be to reduce, as
much as practicable, the irritability and vital
force of the muscles which act on the dis-
located bone before any of our mechanical
appliances be resorted to. When the general
system of the patient has been under the de-
pressing influence of the usual means, viz.
tartanzed antimony, &c., and under these fa-
vourable circumstances the surgeon has with
patience and perseverance used all the force
that he deems expedient or justifiable, and has
not succeeded in replacing the bone, our expe-
rience would induce us to recommend that in
such a case no further measures should be had
recourse to. We have, in the museum of the
Richmond Hospital, a cast of the hand of a
man who had suffered this luxation sixteen
years before the cast was taken. The history
he gave the writer was briefly that he consulted
an eminent surgeon, who used all the means in
his power to reduce the dislocation, but could
not succeed; that the surgeon then proposed
to the man an operation which he explained,
and which from the patient's description of it
we may conclude consisted in laying bare the
head of the metacarpal bone and removing it,
as had been about that time recommended by
Mr. Evans, of Kettley near Wellington ; the
man, however, refused to consent to the pro-
posal, and had good reason to be content with
his own determination, as he can now oppose
the point of the thumb to the other fingers, and
can follow his business, which is that of a plas-
terer, with very little inconvenience, affording
us a proof that the advice given by Sir A.
Cooper relative to irreducible dislocations of
the metacarpal bone, may be well extended to
the common dislocation backwards of the first
phalanx, viz. " that if the bone cannot be re-
duced by simple extension, it is best to leave
the case to that degree of recovery which nature
will in time produce, rather than divide the
muscles or run any risk of injuring the nerves
or the bloodvessels."

The first phalanges of any of the other fin-
gers may be luxated backwards. The little
finger appears to us, after the thumb, the most
liable to this accident ; it is sometimes difficult
to reduce. Mr. Romer, a pupil of the Rich-
mond Hospital, lately brought to the writer a
patient who was the subject of luxation of the

2 M

514

ABNORMAL CONDITIONS OF THE HAND.

first phalanx of the little finger on the back of
its metacarpal bone. This patient was a female
about thirty-five years of age ; the bone had
been only a few hours luxated, and some inef-
fectual attempts had been previously made to
reduce it. The reduction was effected with
some little difficulty by at first increasing the
extension, and then by forcibly flexing the last
phalanx. In this case the long extensor tendon
of the little finger was displaced from its sheath
and groove, and lay on the ulnar side of the
metacarpal bone and luxated phalanx, and
never afterwards could be maintained in its
proper place. This accident is very easily re-
cognized, yet it has been occasionally left un-
reduced.

It has been stated already that luxation of
the first phalanx of the thumb forwards may
occasionally happen, and we have also good
authority for supposing that a similar luxation
may occur to the phalanx of the index finger.
These accidents, however, are very rare ; the
middle, ring, and little fingers have never been
seen thus displaced ; indeed, Boyer seems to
think such an accident in these last, impossible
from the nature of their articulation with their
metacarpal bones.

Luxation of the second, and third or distal
phalanges. — The articulations of these pha-
langes being only covered by the skin and the
tendons of the flexor and extensor muscles,
their luxations are also very easily recognized.
In the luxation backwards, the only one which
we have had occasion to observe, the luxated
phalanx is turned to the side of extension, and
forms with the phalanx above it an angle more
or less open. When it is the second phalanx
which is luxated, the third is flexed by the
elongation of the tendon of the deep flexor,
and it is impossible to extend it or flex the
second. The reduction of these luxations is
generally easy if time be not allowed to elapse
between the occurrence of the luxation and the
period of attempting its reduction.

II. DISEASED CONDITIONS.

Caries and necrosis occasionally affect the
bones of the hand, but the complete descrip-
tions of these diseases, which have been else-
where given in this work,* render superfluous
here any special observations on these morbid
actions when they manifest themselves in the
region of the hand. The bones of the meta-
carpus and phalanges are very frequently de-
formed by a disease which (although it cannot
be said to be exclusively observed in these
bones) produces on the hand and fingers ap-
pearances too remarkable to be left unnoticed
in this place.

The disease which we wish to describe as we
have seen it in the bones of the hand would be
by some designated as exostosis,f by others as
benign osteo-sarcoma, and others]: would be

* See BONE, morbid anatomy.

t See Scarpa, De Anatomia etPathologia ossium,
cum tabulis aeneis, tab. vi.Jig. 1, Exostosis ossium
plerorumque maims dexterae.

$ Boyer, Maladies Chirurgicales, vol. Hi. p. 579.

disposed to preserve the somewhat objection-
able but ancient name of spina ventosa.

The metacarpal bones and the phalanges of
the fingers are the usual seat of this disease,
and in general many of them are simulta-
neously engaged in it; the shafts of the affected
bones are usually swelled out by the disease
into tumours somewhat of a globular form, the
articular extremities of the bones remaining
perfectly free. It is by no means unusual to
see the first and second phalanx of a finger
forming two distinct globular swellings, while
the last or distal phalanx is perfectly free from
enlargement.

It has been already mentioned that these
tumours, when viewed externally, seem to have
a spheroidal form ; but when the integuments
of the bony shell which incloses the tumours
are removed, we discover on their palmar as-
pects the flexor tendons buried in deep grooves.
This is of course best seen when the disease
has existed long, and the tumours have attained
a considerable size.

If we have an opportunity of examining ana-
tomically the phalanges while the disease is
yet in its early stage, we shall find reason to
conclude that the morbid process had com-
menced deep in the interior of the bone, and
that the tumour proceeding outwardly presented
itself first on that aspect of the phalanx, or me-
tacarpal bone, where there was the least resist-
ance opposed to it; hence we usually notice
these tumours, when small, shewing themselves
most on the dorsal aspect of these bones. As
the disease increases the)- swell out laterally,
and the whole circumference of the phalanx
would be equally expanded were it not for the
support given on the side of flexion by the
flexor tendons and their strong fibrous sheaths.
The integuments of these tumours preserve their
natural sensibility, and are at first freely move-
able over them ; but as the swellings gradually
increase and undergo a species of softening in
certain points, the integuments become adhe-
rent at these points, and circular openings are
formed in them which correspond to similar
circular apertures in the shell of the bone, and
through which the bony cy^ts discharge their
contents ; these swellings of the bones of the
hand, as far as we know, never degenerate into
any disease of a malignant nature ; but when
they attain a considerable size, and are exca-
vated by these cysts, and have large fistulous
orifices, the irritation they produce and the
discharge cause some febrile excitement of the
constitution, and amputation may become ne-
cessary. The following very remarkable case
clearly proves the non-malignant nature of this
disease; the history of it will serve well to illus-
trate the natural progress of this form of dis-
sease in the hand.

A countryman of rather a delicate appear-
ance, aged twenty-four years, was admitted
into Jervis-street Hospital, July 22,1828, under
the care of Dr. O'Beirne. This man had an
enormous enlargement of the left hand, which
arose from a tumour, the principal seat of which
was in the first and second phalanges of the
middle finger, but the ring and index finger

ABNORMAL CONDITIONS OF THE HAND.

515

were also involved in the disease, and the three
metacarpal bones supporting the three fingers
already mentioned were also much enlarged; in
a word, all the bones of the metacarpus and
fingers, with the exception of those of the
thumb and little finger viewed externally,
seemed to enter into the formation of one mor-
bid mass, the size and form of which may be best
conceived by a reference to the annexed figure.
The chief bulk

Fig. 227. of this large bony

tumour existed
posteriorly, where
it extended as
high up as the line
of the wrist-joint,
and completely
concealed the
bones of the car-
pus. The tumour
did not extend it-
self directly for-
ward towards the
palm of the hand,
but passed down-
wards; at its re-
mote extremity
the last phalanx
of the middle fin-
ger was to be seen
projecting ; this phalanx was itself, however,
perfectly free from morbid change, and the
integuments covering it possessed their natural
sensibility. The circumference of the tumour
measured accurately twenty-four inches; nume-
rous very large protuberances shewed themselves
every where on its surface, which yielded but
little to pressure. Three of these tumours had
ulcerated at their most prominent points, and
by circular depressed openings (nearly an inch
in diameter) gave exit to a thin fetid ichorous
matter, which continued to flow from the in-
terior of the morbid mass. These orifices, which
presented some loose granulations, readily ad-
mitted the introduction of a probe, which could
be then freely moved in the interior of these
cavities, each of which was large enough to
contain an ordinary hen's egg. The integu-
ments every where over the whole of this mor-
bid growth had a perfectly healthy aspect, and
were freely moveable on this immense tumour,
except at the borders of the circular apertures
already mentioned. The disease existed for
many years, having begun, as the patient stated,
when he was a boy.

The disease was unaccompanied by pain, and
the man's health continued good until the pe-
riod when the tumour had ulcerated; after which
he became somewhat debilitated by the exhaust-
ing effect of the sanious discharge on his con-
stitution, and his mind was depressed with the
idea of his being afflicted with a disease so
formidable in appearance, and which hitherto
had resisted, nay increased under, all treatment,
and deprived him altogether of the means of
earning a livelihood. Although there was some
difference of opinion as to the name by which
this disease of the bone should be designated,
it was agreed that there was nothing really ma-

lignant in its nature; most of those consulted
on the case recommended amputation, but
Doctor O'Beime conceived the happy idea,
and speedily put it into execution, of cutting
out the morbid mass. Although it was rightly
conceived that the index finger was but little
diseased, and that the ring-finger was merely
enveloped in the tumour, still the thought of
preserving either of these fingers could not be
for a moment entertained, as the metacarpal
bones supporting them were known to be dis-
eased. It was plain that the thumb and little
finger only could be saved, and the lines of
incision which were followed may be easily
imagined. The operation was performed thus :
one incision was commenced at the root of the
little finger at its radial side, which was ex-
tended deeply through the soft parts upwards
and backwards as high nearly as the wrist-joint ;
the termination of this incision here was met
by another, which was commenced at the first
interosseous space between the index finger and
the thumb ; the lines of these incisions were
followed deeply, and, with the assistance of the
knife and metacarpal saw, the whole of the
morbid mass was removed; the haemorrhage
was soon arrested, and dressings applied with a
bandage to approximate gradually the thumb
and little finger. The wound was at first refrac-
tory, and cartilaginous granulations sprang up ;
to repress these, Dr. O'Beirne found nothing
so effectual as the actual cautery, and under its
influence the wound healed kindly.

It is now nine years since the operation was
performed, and the man has, during that period,
enjoyed vigorous health ; the thumb and little
finger have approached each other, and in-
creased much in size, power, and usefulness,
and he is fully competent to follow his oc-
cupation, which is that of a land-surveyor.

We have, in our collection at the Richmond
school, a cast of this remarkable hand ; and the
morbid mass which was removed is preserved
in the Museum of the Royal College of Sur-
geons, Dublin. A longitudinal section has been
made of the tumour : one half has been sub-
jected to long maceration, and dried ; and this
half exhibits well the thin osseous shell which
encloses the cellular and reticulated bony struc-
ture of the whole mass ; — this portion of the
section shews, in short, the true structure of the
bony basis or skeleton (if we can so say) of the
disease (fig. 228). The
other half of the section
has been preserved in
spirits, and in the line of
division shews a smooth
cartilaginous surface, and
several excavations lined
by a smooth membrane,
which had enclosed an
albuminous fluid. Some
of these cavities were
complete isolated cysts,
buried deep in the in-
terior of the cartilaginous
mass; but the contents
of three of these cysts
had made their way ex-
2 M 2

Fig. 228.

516

ABNORMAL CONDITIONS OF THE HAND.

ternally through the large circular apertures
already mentioned.

We have thought it right to detail this re-
markable case at length, as it is the history of
an important fact, from which, it is true, differ-
ent conclusions may be drawn ; for our part, we
consider the case a well-marked specimen of a
disease described by some of the older writers
as spina ventosa. Boyer adopts this appella-
tion, and in his work will be found a good
account of the disease; and, indeed, he so
accurately depicts the appearances we observed
in this case, and which were discovered by dis-
section, that we feel satisfied his description has
been drawn from nature. Boyer says, " We
understand by spina ventosa an affection of
the cylindrical bones, in which the walls of the
medullary canal are subjected to a slow, gra-
dual, but sometimes enormous, distension ;
while, at the same time, they are considerably
thinned, and even pierced in many points, in
which their tissue undergoes a singular rarefac-
faction, — a disease whose primitive seat would
appear to reside in the medullary cavity," &c.

Sanson, from two careful dissections of recent
specimens of this disease, considers it to origi-
nate in a degeneration of the membrane which
lines the interior of the bone. The substance
which is found to fill up the cavity of the bone
can only proceed from the system of the me-
dullary membrane, the action of which becomes
so altered and diseased, as to produce the new
growth which is found in the interior of these
globular tumours. This product distends by
degrees the walls of the medullary canal and
reticular structure of the bones. The dilatation,
in which the articular surfaces do not partici-
pate, is generally sudden, so that the part imme-
diately near the point where the disease is
situated preserves its natural dimensions. When
the globular tumours thus formed are cut into,
in the early stage of the affection, their interior
presents a fibro-cartilaginous appearance, sur-
rounded by a thin shell of bone. A section
of one of those tumours of the fingers in the
early stage appears to us to present a striking
resemblance to the common fibrous tumour of
the uterus, which is often encased in a similar
bony shell. The description Mr. Crampton
has given of the structure of the benign osteo-
sarcoma may well be applied to this disease.
He says, " the interior of the tumour presents
a great variety of structure, but I should say,
in general, that the cartilaginous character which
the tumour exhibits in its origin prevails to the
last. In the early stages of the disease, the
tumour consists of a dense elastic substance,
resembling fibro-cartilaginous structure ; but
the resemblance is more in colour than in con-
sistency, for it is not nearly so hard, and it is
granular rather than fibrous, so that it breaks
short. On cutting into the tumour, the edge of
the knife grates against spiculse, or small grains
of earthy matter with which the substance is
beset. If the tumour acquires any considerable
size, it is usually found to contain cavities filled
with a fluid differing in colour and consistency ;
but in general the fluid is thickish, inodorous,
arid of the colour of chocolate. Sometimes the

growth of the tumour, and the secretion of the
fluid within its substance, is so slow, that the
deposition of bony matter keeping pace with
the absorption, the bone becomes expanded into
a large thick bony case, in which the tumour is
completely enclosed."1*

Strumous osteitis of the metacarpal bones, and
of the phalanges of the fingers. — It is by no
means difficult to distinguish the disease last
described under the name of spina ventosa, or
benign osteo-sarcoma, from that enlargement of
the metacarpal bones and of the fingers which we
frequently witness in children of the strumous
diathesis. The strumous affection of the pha-
langes we allude to seems little else than an
osteitis, which terminates usually either in caries
or necrosis. The disease, when fully formed,
shows itself in the shape of either a pyrifonn
or globular swelling of the phalanx of one or
more of the fingers. There is at first no sensi-
ble alteration of the surrounding soft parts ; the
swelling has usually been preceded by pains
of a dull and obtuse character ; the movements
of the part affected are for a long time preserved,
and indeed are not at all restrained, except
when the tumefaction of the bone becomes
sufficient to turn aside the tendons from their
natural direction, or to cause deformity of the
articular surfaces, which rarely happens.

As the disease advances, the soft parts are
distended, suppuration takes place, and the
integuments of the swollen part always ulcerate
at a point corresponding to some deficient part
of the bony cylinder. Through the ulcerated
opening a probe may be passed freely into a
cavity which the bone contains; the opening
becomes fistulous, and for a long time continues
to give exit to a moderate quantity of thin,
serous, and ill-conditioned matter; sometimes,
however, we notice an improvement in the ge-
neral health of the patient, and, at the same
time, the local disease assumes a new and more
favourable aspect, the discharge diminishes, and
at length dries up. Such a decided amendment,
however, seldom occurs, until a process of ne-
crosis, or exfoliation of a part of the bone, has
taken place; after which the wound heals up,
the use of the finger is restored, arid all that
remains of the disease is an unseemly, depressed,
and adherent cicatrix.

Malignant tumours of the hand. — Malignant
osteo-sarcoma, and even fungus haematodes, are
diseases which may show themselves in the
region of the hand and fingers ; but these dis-
eases are readily distinguished from the spina
ventosa, or benign osteo-sarcoma, above alluded
to. The pains of the malignant disease are
lancinating, the progress is more acute, the con-
stitution and health are more quickly and deeply
implicated ; the prognosis, too, is very different.
Although life may perhaps be prolonged by an
amputation of the hand of a patient affected
by either of these malignant diseases, the terri-
ble disorder will almost uniformly recur. On
the contrary, if the disease be spina ventosa, a
portion of the hand may be amputated, or a
finger removed, and the disease shall notrecur

* Vide Dublin Hospital Reports, vol. iv. p. 542.

ABNORMAL CONDITIONS OF THE HAND.

517

after these operations. Indeed, we feel per-
suaded that, in some cases of spina ventosa,
(Jig. 229) the tumour may be cut off from
a finger or from a me-
Fig. 229. tacarpal bone, and that

although the wound
may for a while throw
up cartilaginous gra-
nulations, still, under
proper treatment, the
ulcer of the bone will
be got to heal kindly.

Abnormalconditions
of the fingers the re-
sult of accidents and
morbid affections oj'one
or more of their consti-
tuent structures. — We
occasionally find that
the voluntary power of
flexing or extending the
joints of the fingers is
lost. This loss of
power may arise from
a great variety of
causes; — anchylosis of a joint from acute
or chronic inflammation; the loss of an ex-
tensor or flexor tendon from a similar cause,
or from a wound; congenital malformation of
the brain; disease or accident affecting this
organ, the spinal marrow, or the nerves con-
nected with the movements of the upper extre-
mity ; any of these may at times be the source
of this loss of the voluntary power over the
fingers. Under these circumstances, although
there may be but little external deformity,
sometimes the fingers cannot be flexed; more
frequently they cannot be voluntarily extended.
An abnormal condition of the fingers, shewing
itself in some distortion of these organs, may
be traced to causes affecting — 1, the skin; 2,
the fascia; 3, the theca of the tendons; 4, the
tendon itself; and 5, the bone. If a burn pe-
netrate the skin on the palmar surface of the
hand, a dense cicatrix will be formed ; and much
exertion will be necessary, on the part of the
surgeon, to oppose successfully the gradual con-
traction of the " tissue of the cicatrix." Should
contraction take place, notwithstanding these
efforts, the functions of the hand will be im-
paired, and much deformity will remain. A
burn on the back of the hand may be followed
by analogous effects.

There is a peculiar form of contraction of
the fingers, which Boyer seems to ascribe (we *
believe erroneously) to a shortening of the ten-
dons. Adopting the language of the ancients,
he denominates the affection "crispatura tendi-
num." This contraction of the fingers is never
seen in very young persons. Most of those
we have known affected by it were adults, who
had been for a long time compelled to make
laborious use of their hands. The disease will
be ordinarily found to commence in a contrac-
tion of the little finsrer ; the ring finger is next
engaged, and then the middle finger. From
day to day the fingers become more contracted,
and the power of extending them is lost. When
one hand is thus affected, it usually happens

that the other soon becomes equally engaged.
It is remarkable that neither the indicator nor
the thumb have ever been seen affected with
this disease.

When we examine the fingers the subjects of
this species of contraction (Jig. 230), we find
that the first phalanx is moveable on the meti-
carpal bone, and is flexed at an angle more or
less approaching to a right angle. We can flex
it a little more towards the palm ; but to extend
it so as to efface the angle is impossible; "a
weight," says Dupuytren, "of 150lbs. will not
bring the finger into a straight line with its me-
tacarpal bone." Boyer says, " our efforts to
extend the fingers are resisted to such a degree,
that if we continued them they would break
before we could force them to yield."

Fig. 230.

Contraction of the fingers from disease of tlie palmar
fascia.

This description, however, applies only to the
metacarpal joint of the first phalanx, for the last
phalanges of each affected finger, though move-
able, habitually remain perfectly straight.

In these cases the integuments of the affected
palm and the subjacent fascia seem to be more
than naturally thick and consolidated, and we
observe the lowest of the natural cutaneous
lines of the palm thrown into a very deep
crescentic fold, the concavity of which looks
towards the fingers, and the convexity towards
the wrist joint. W« also invariably notice in
these cases a rounded projecting chord which
passes downwards from the middle of the
palm of the hand to the basis of the first
phalanx of the contracted finger. This chord
feels hard, and is rendered more tense and
salient whenever we make an effort to straighten
the affected finger.

When in the living subject we examine care-
fully the palmar fascia, and explore, as far as
we can, its connexion above with the tendon of
the palmaris longus, and below, follow the pro-
longations it sends to the lateral aspect of the
contracted fingers, we find them all continuous;
in a word, when we press upon the tendon of
the palmaris longus, we make tense the tendinous
digitations above-mentioned. The continuity
of all these fibrous structures is thus evident in

518

ABNORMAL CONDITIONS OF THE HAND.

the living. When we have opportunities of
examining, in the dead subject, a hand in which
this contraction of the palmar aponeurosis has
existed, and have raised the skin in all its ex-
tent from the palm of the hand and palmar sur-
face of the fingers, its folds and rugae all dis-
appear, and it then becomes evident that this
defect does not reside in the skin. When the
aponeurosis is exposed, it is found contracted,
thickened, and diminished in length. From its
inferior part, the tense fibrous chords which
were already supposed to exist are now exposed,
and seen to be inserted into the periosteum on
the lateral aspects of the contracted finger.

Dupuytren, by various anatomical and pa-
thological investigations of this disease, satisfied
himself that this peculiar contraction of the
fingers depends essentially on this shortening,
thickening, and organic alteration of the palmar
aponeurosis and the digitations proceeding from it
to the sides of the fingers ; for he invariably found
when he had opportunities of investigating this
disease in the dead subject, that the tendons
were of their accustomed volume and mobility.
He cut them across, and then made efforts in
vain to extend the finger. The bones were
found of their natural form, and no alteration
was perceptible in either the synovial mem-
branes or lateral ligaments ; but as soon as the
section of the expansions of the fascia which go
to the fingers was effected, the flexion dis-
appeared, and the finger could be brought to
its normal position. Finally, he infers, and
indeed, as far as a few instances go, he proves,
that a similar result will follow the division of
the fascia in the living subject, and that the
proper use and adjustment of a peculiar splint
on the back of the forearm and hand, so as to
keep the affected fingers for a time extended,
will complete the cure of this disease.

Sir A. Cooper alludes to these deformities
when he says, " The fingers are sometimes con-
tracted by a chronic inflammation of the theca
and aponeurosis of the palm of the hand, from
excessive action of the hand in the use of the
hammer, the oar, ploughing, &c.," evidently
recognising two species, in one of which the
aponeurosis is the cause of the contraction, and
the contracted hand is narrow. " And this
hand," he adds, " may with advantage be di-
vided by a pointed bistoury, introduced through
a small wound in the integuments; the finger
may be then extended, and a splint applied to
preserve it in the straight position." But he
observes that " where the theca is contracted,
nothing should be attempted for the patient's
relief, as no operation or other means have suc-
ceeded."

Anchylosis of some of the joints of the
phalanges sometimes succeeds to an attack of
acute or chronic inflammation of one or more
of these small articulations; this may have
arisen from disease ; for example, paronychia or
accident; but from whatever cause the inflam-
mation has arisen, anchylosis of a finger in the
extended position, which cannot be contracted,
or of a joint in the flexed position, which can-
not be extended, is the too frequent result. The
history of the case, and the actual state of the

anchylosed joint, which cannot be overlooked,
will prevent the surgeon from falling into any
eiror in his diagnosis. A contracted state of
the ring finger and little finger is frequently to
be noticed in those who have suffered much
from gout; but we are acquainted with no dis-
ease which more frequently produces deformity
of the hand and fingers than chronic rheuma-
tism (chronic rheumatic arthritis). This mor-
bid condition of the joints of the hand is too
cursorily alluded to by authors under the head
of rheumatic gout, nodosity of the joints of the
fingers, &c. &c. It is a complaint which is erro-
neously supposed to be met with only in elderly
persons. We have, however, in the pauper de-
partment of the House of Industry in Dublin,
examples of it in females under the age of 30;
but of course it is more frequently observed in
the aged and rheumatic patient. When the
disease has existed long, the whole hand be-
comes greatly deformed, and the distortion the
fingers have undergone in these cases is of it-
self calculated to impress us with a correct idea
of the sufferings the victims of this disease
have endured. The carpus is usually preter-
naturally convex on its dorsal aspect, owing to
the thickening and distension of the synovial
bursae, which become like solid ganglions. All
the joints of the hand and fingers become en-
larged, particularly those which are formed by
the junction of the first phalanges and metacar-
pal bones ; at these joints the fingers are more
or less flexed towards the palm, and are, at the
same time, adducted or drawn to the ulnar side
of the hand.

The head of the metacarpal bone, where it
joins with the first phalanx of the index finger,
seems particularly swelled and enlarged, and
projects much towards the radial side and dor-
sal aspect of the hand, as is represented infg.
231.

Fig. 231.

Chronic rheumatism, or nodosity of the joints.

The last phalanx of a finger is frequently
flexed, while the middle phalanx is extended.
Whatever be the faulty position which the fin-
gers happen to have assumed, they are usually
found to be remarkably rigid. All movements

MUSCLES OF THE HAND.

519

of them, whether voluntary or communicated
to them, are painful ; and in either case com-
monly a crepitus, produced by the contact of
rough surfaces, is perceived both by patient
and physician when making the examination.

When this disease exists in the hand to this
amount, it will almost invariably be found that
the distressing complaint has also extensively
engaged most of the other articulations.

When we make an anatomical examination
of the hand of those who have died with the
condition of the joints of the fingers above
described, we find that the synovial fluid is
somewhat thicker than usual, and deficient in
quantity. In some of the anchylosed joints we
observe a species of fibro-cellular or ligamentous
union of the bones; almost all the joints are de-
prived of their cartilaginous incrustation, which
seems as it were to have been worn away by
friction ; the porous structure of the root of the
phalanges is often exposed, and in some cases
hollowed out, to accommodate the enlarged
head of the metacarpal bone ; a cup is formed in
the base of the phalanx which is lined with a
porcelainous deposit, while around this little
cup an exuberant growth of new bone of a
looser texture is thrown out. In the removal
of the cartilage without suppuration — in the
substitution for it of a porcelain-like deposit,
and in the surrounding exuberance of new
bone, we find this disease of nodosity of the
joints of the fingers resembling accurately the
analogous affection of the other joints, which
has been supposed to be the slow effects of
chronic rheumatism. — See ELBOW, KNEE, HIP,
ABNORMAL ANATOMY OF.

III. CONGENITAL MALFORMATIONS OF THE
HAND.

Children are occasionally born with one or
two fingers more than the natural number. The
supernumerary finger almost invariably is found
to be an imperfect vegetation, growing from the
ulnar side of the hand, and in general the
deformity is found to exist on both hands.
Examples, however, have been, though rarely,
seen of a sixth finger parallel to the other fin-
gers, and properly supported by a sixth meta-
carpal bone.

It frequently happens that children are
brought into the world with their fingers united
together. This union may be complete, or the
connexion may be loose by means of the skin.
It is known that up to the second or third month
of intra-uterine life an interdigital membrane
exists, and the abnormal condition of the fin-
gers we are now considering is nothing
but a persistence of the early condition
of the fingers in the foetal state. It seems
pretty well proved that these congenital defects
are very frequently hereditary, and that when-
ever the fingers are the seat of them, the toes
are similarly affected.

The whole hand, or one or more of the fin-
gers may suffer in utero what has been denomi-
nated spontaneous amputation, and the stump
will present peculiarities already noticed. — See
Fai LS, jig. 155, 159.

(R.Adams.)

HAND, MUSCLES OF THE. (Human
Anatomy.) The varied and beautiful move-
ments of which the hand is capable are effected
by muscles belonging to separate and distinct
regions, — namely, one set of muscles which are
the proper and intrinsic muscles of the hand
itself, and a second set, which are continued into
the dorsal or palmar region of the hand from
the posterior or anterior surface of the fore-arm.
In the present article it is proposed to describe
the intrinsic muscles of the hand ; but in con-
sidering the actions of that member or of any
of its segments, it will be necessary to notice
how far the second set of muscles contribute to
or aid in their production.

The proper or intrinsic muscles of the hand
may be divided into — 1, those on the palmar;
2, those on the dorsal surface.

I. The muscles of the palm are fifteen in
all. For convenience of description they may
be classified into, a, those of the thumb, or
external palmar region, constituting the thenar
eminence ; b, those of the little finger, or in-
ternal palmar region, forming the hypothenar
eminence ; c, those that occupy the hollow of
the hand, or the middle palmar region.

a. Muscles of the external palmar region. —
The muscles of this region, all of which belong
to the thumb, are four.

1. Abductor pollicis manus* (scaphoido-
phalangien, Cruveilh.) short, flat, broader above
than below ; it arises from the anterior surface
of the scaphoid and trapezium, the superior,
anterior, and external part of the anterior annu-
lar ligament, and generally from a prolongation
of the tendon of the extensor ossis metacarpi,
by aponeurotic and fleshy fibres. It proceeds
outwards and downwards to be inserted into
the outer edge of the upper extremity of the
first phalanx of the thumb. Sometimes the
two origins of this muscle are not incorporated
for some distance, giving the appearance of
two muscles.

Relations. — It is covered by the skin and
external palmar aponeurosis. It covers the
opponens, a few fibres of which appear to its
radial side, running in a transverse direction.
It is separated by a thin cellular line from the
short flexor, which is on the same plane.

The obvious action of this muscle is to draw
the thumb forwards and inwards, thus sepa-
rating it from the fingers.

2. Flexor ossis metacarpi, or opponens polli-
cis (trapezo-metacarpien, Cruveilh.), of a
rhomboidal form ; it arises from the trapezium,
and from the fore part of the anterior annular
ligament, anterior to the sheath for the radial
flexor of the wrist, by long aponeurotic fibres ;
and posteriorly from a septum between it and
the short flexor. From these attachments the
fleshy fibres radiate downwards and outwards,
being so much the shorter the higher and the
more transverse they are. They terminate by

* Soemmering and Albinus divide this into two
distinct muscles, the former giving them the names
abductores breves pollicis manus interior et exterior ;
the latter calls the internal portion abductor brevis
alter.

520

MUSCLES OF THE HAND.

short aponeuroses along all the outer edge of
the first metacarpal bone.

Relations. — With the exception of a small
portion of its external border, this muscle is
covered anteriorly by the preceding muscle. It
covers the anterior surface of the first meta-
carpal bone, and its articulation with the tra-
pezium.

Jt draws the thumb inwards, turning it upon
its own axis, so that it opposes its palmar
aspect to the other fingers.

3. Flexor brevis pollicis manus (trapezo-
phalangien, Cruveilh.) is a larger muscle than
the two preceding ones, triangular, bifid supe-
riorly, having its anterior surface channelled ;
arises by aponeurotic and fleshy fibres, exter-
nally from the fore and under part of the
annular ligament, and from the process of the
trapezium, internally and posteriorly from all
the reflected portion of the annular ligament,
forming the sheath for the radial flexor and
extending to the os magnum, and from the os
magnum often by a distinct portion. From these
various origins the fleshy fibres run downwards
and outwards, are more oblique as they are
more internal, and terminate in a strong fleshy
bundle which is attached to the external sesn-
moid bone and outer side of the first phalanx.

Relations. — This muscle is covered by the
external palmar aponeurosis, more internally by
the tendon of the long flexor of the thumb, then
by the common flexor tendons. It covers the
first dorsal interosseous, the tendon of the
radial flexor of the wrist, and a small portion
of the external margin of the adductor of the
thumb. Its outer edge corresponds to the
abductor and is often confounded with the
opponens, and its inner would be undistin-
guishable from the abductor near the first meta-
carpal bone, if it were not separated from it by
the arteria magna pollicis,* — a fact that appears
to have been overlooked by many anatomists,
or the descriptions of the attachments of this
muscle would never have been so much at
variance : the foregoing description coincides
with that of Meckel and Cruveilhier. Its
tendon of insertion is covered by that of the
abductor, which is external to it.

This muscle is badly named, at least if
names be intended to denote action, for its
power of flexing the thumb is very slight ; but
it has considerable power as an opposer of it,
its insertion being especially favourable to that
action.

4. Adductor pollicis manus (metacarpo-pha^
lungien du pouce, Chauss.) is the largest muscle
of the thumb as well as the most internal ; in
shape it is a perfect triangle, arising from all
the anterior border of the third metacarpal
bone, from its articulation with the magnum,
from the anterior and superior portion of the
trapezoid, and from the palmar interosseous
aponeurosis in its central portion. From this
extensive attachment the fibres run transversely
outwards, the superior ones being most oblique;
they converge to a strong fleshy bundle, which

Alro derp in the palm, it is generally sepa-
rated frcm the adductor by the deep palmar arch.

is inserted by means of the internal sesamoid
bone into the first phalanx of the thumb.

Relations. — Its two internal thirds are covered
by the lumbricales and common flexor tendons,
aiso by a layer of the deep interosseous apo-
neurosis which constitutes its sheath. It covers
the two first interosseous spaces. Its inferior
border is subcutaneous, especially posteriorly,
where it may be felt in the fold of skin extend-
ing from the index finger to the thumb.*

Its name implies its action ; it draws the
thumb towards the median line of the hand.

b. Muscles of the internal palmar region. —
There are four muscles in this region also; one
is a cutaneous muscle, the palmaris brevis ; the
others are proper to the little finger, and are
inserted into the inner side of its first phalanx
and the fifth metacarpal bone. They consist,
as the last described set, of an abductor, short
flexor, and an opponens minimi digiti.

1. Palmaris brevis (peaucier de (a main,
Cruveilh.) This muscle when it exists, (for in
weakly subjects its fibres are often not to be
distinguished, though on the other hand it
acquires considerable volume in those that are
muscular,) arises by aponeurotic intermingled
with fleshy fasciculi which run horizontally
inwards, forming a small quadrilateral muscle
which terminates in the skin.

Relations. — Covered by the skin and im-
bedded in the adipose substance, it is spread
over the muscles of the little finger and the
ulnar artery and nerve, from which it is sepa-
rated by the internal palmar aponeurosis.

It increases the concavity of the palm by
puckering the skin over the part it occupies,
thereby drawing the hypothenar eminence for-
wards and outwards, and rendering it more
convex.

2. Abductor minimi digiti (pisi-phulangien,
Cruveilh.) A long flat muscle, broadest at its
centre, arising from the pisiform bone and from
an expansion of the flexor carpi ulnaris, by
strong aponeurotic fibres, which soon become
fleshy, running along the inner edge of the
fifth metacarpal bone. It ends in a flattened
tendon, which is inserted in common with the
short flexor into the inner side of the first
phalanx, sending an expansion into the extensor
tendon.

Relations. — It is covered by the internal
palmar aponeurosis, itself covering the oppo-
nens.

U&e. — It draws the little finger inwards and
forwards, separating it from the others.

* Sometimes this muscle is separated into two
bellies, the one superior and the other inferior,
which are completely separate from each other,
and of which the superior is by far the greater. lu
this case the first arises solely from the os magnum
or from this bone and a small portion of the
superior extremity of the third metacarpal bone,
while the second arises irom the inferior portion of
the anterior head of the third, fourth, and some-
times even the fifth metacarpal bones; it runs
transversely outwards and a little backwards to
meet the superior head at the first phalanx of the
thumb. This anomaly resembles the normal con-
dition of the transverse and oblique adductors of
the great toe. Meckel, Annt. vol. ii. p. 1£5.

MUSCLES OF THE HAND.

521

3. Flexor brevis minimi digiti (unci-pfialan-
gien, Cruveilh.) — This muscle is external to the
last; it arises from a small portion of the annu-
lar ligament and from the anterior part of the
unciform process ; it runs downwards and in-
wards to join the last described muscle, with
which it is inserted.

Relations. — At its origin it is separated from
the abductor by the ulnar vessels and nerve,
but it soon becomes confounded with it.
Chaussier described them both as one muscle.
It is often wanting. In concert with the last,
it abducts and slightly flexes the little finger.

4. Adductor ossis metacarpi or opponens
minimi digiti ( unci-metacarpien, Cruveilh ) — It
resembles in disposition and form the opponens
pollicis. Having the same origins with the
preceding muscle, its fibres proceed downwards
and inwards, the superior being nearly hori-
zontal ; they are inserted into all the internal
border of the fifth metacarpal bone.

Relations. — It is covered by the two last
muscles ; its posterior surface is applied to the
fifth metacarpal bone, the corresponding inter-
osseous, and the tendon of the flexor sublimis
going to the little finger.

It carries the fifth metacarpal bone forwards
and outwards, thereby augmenting the cavity
of the hand, and in a measure opposing the
little finger to the thumb, but the articulation
of the metacarpal bone with the os unciforme
allows of so very little rotatory motion, that it
is rather a motion of adduction and tiexion
than of opposition.

c. M uncles of the middle palmar region. —
In the middle palmar region we have seven
muscles, four connected to the tendons of the
flexor profundus, the lumbricales, so called
from their resemblance to earth-worms; and
three deeper-seated muscles, the palmar inter-
ossei occupying a part of the second, third, and
fourth interosseous spaces between the meta-
carpal bones, the remaining part of those spaces
being filled up by muscles ; we shall presently
examine the dorsal interossei.

1. Lumbricales (Jlectentes primum interno-
dium, Spig.) are four slender, elongated, fusi-
form, fleshy bundles, attached to the tendons of
the flexor profundus, just after it escapes from
under the annular ligament, distinguished into
first, second, &c. from without inwards. The
first arises from the fore and outer part of the
flexor profundus tendon belonging to the index
finger, sometimes also from the accompanying
tendon of the flexor sublimis ; the recoiid lum-
bricalis arises from the radial side of the tendon
of the same muscle destined to the middle
finger ; the third said fourth are double penni-
form arising from the opposed surfaces of the
three internal tendons of the same muscle;
from these attachments they proceed, the two
middle vertically downwards, the outer out-
wards, the inner inwards, towards the outer
side of the metacarpo-phalangeal articulations
of the fingers, where they end in flat broad
tendons, which are inserted into the outer
border of the common extensor tendon, in
common with the tendons of the correspond-
ing interossei with which they are confused ;

they assist in completing the sheath which the
extensor tendons form for the back of the
fingers.

Relations. — Their anterior surface is covered
by the tendons of the flexor sublimis, by the
palmar aponeurosis, and collateral vessels and
nerves of the fingers. Their posterior surface
lies upon the interossei, the inferior transverse
metacarpal ligament, and the phalanges.

Use. — They assist in the flexion of the fingers
upon the metacarpus, at the same time drawing
them outwards, they steady the extensor ten-
dons, keeping them applied to the phalanges.

The interossei, of which there are seven in all,
are small muscles situated between the meta-
carpal bones, to which they are attached supe-
riorly, their inferior attachment being to the
sides of the first phalanges and the extensor
communis tendons; there are three on the pal-
mar aspect, which are simple, and four on the
dorsal aspect of the hand, which are bifid mus-
cles ; there are two to each interosseous space,
excepting the first, which has only one : we
shall first examine the palmar interossei.

2. Interossei interni digitorum manus, (meta-
carpo-p/ialangiens laterau.c palmaires, Chauss.)
Short, prismatic, and triangular; they arise, the
first, or posterior indicis, from the root and inner
side of the metacarpal bone of the fore-finger ;
the second, or prior annularis, from the root and
outer s.de of the metacarpal bone of the ring
finger ; the third, or interosseus auricularis,
from the root and outer side of the metacarpal
bone of the little finger. They extend along
the metacarpal bones, to which they are attach-
ed, and are inserted by short tendons; the
second and third in common wTith those of the
lumbricales, into the outer and upper, and the
first into the inner and upper part of the corre-
sponding first phalanges and side of the exten-
sor tendons.

Relations. — Anteriorly they are covered by
the deep flexor tendons and palmar muscles ;
posteriorly they correspond to the dorsal inter-
ossei, which are also connected with them
along their unattached margin.

Use. — The simplest way of regarding their
action, which is rather complex, is to refer it
towards the axis of the hand or a central line
drawn through the third metacarpal bone and
the middle finger, in which case it is easily
perceived that the palmar interossei are adduc-
tors towards the axis of the hand.

II. The only intrinsic muscles on the dorsal
aspect of the hand are the dorsal interossei,
interossei ejcterni digitorum manus. Their com-
mon points are, that they appear both on the
dorsal and palmar aspects of the hand ; they
are bicipital ; arising from the opposed surfaces
of two metacarpal bones, both heads termina-
ting in a common tendon, which is attached to
the sides of the first phalanges and extensor
tendons that are not supplied by the palmar in-
terossei. They are four in number; the first,
or adductor indicis, alone merits a particular
description. It is the largest ; arising from the
superior half of the external border of the first
metacarpal bone, and externally from all the
external surface of the second metacarpal bone;

522

MUSCLES OF THE HAND.

these origins are separated by a fibrous arch,
through which the radial artery passes ; they
are large and fleshy, and soon unite, forming a
triangular flattened muscle, which is inserted
into the external side of the first phalanx. The
insertion of the other muscles are, the two mid-
dle into either side of the first phalanx ; they
are called the prior and posterior medii; and
the last, or posterior annularis, into the inter-
nal side of the ring-finger.

Relations. — Posteriorly they correspond to
the extensor tendons and skin ; anteriorly they
appear beside the palmar interossei, from which
they are separated by a strong septum derived
from the deep palmar aponeurosis. Their other
relations are the same as the palmar interossei.
The first, the abductor indicis, corresponds an-
teriorly to the adductor pollicis and part of the
flexor brevis, which it crosses at right angles ;
its inferior and external margin is subcuta-
neous.

Use. — They are all abductors of the fingers
from the axis of the hand, and by reason of
their insertion into the extensor tendons, act
best when the hand is extended. The same
may be said of the palmar.

Before we enter on the general uses of this
complex muscular apparatus, it would be well
to remark that the proper muscles of the thumb
and little finger appear to be nothing more than
exaggerated and multiplied lumbricales and in-
terossei. We may, in this light, view the short
flexor of the thumb as the first lumbricalis, its
abductor and opponens as a dorsal interosseus,
while its adductor would represent a palmar
interosseous muscle; again, as regards the little
finger, its abductor and short flexor together
personate a dorsal interosseus, while its adduc-
tor would be but an internal or palmar inter-
osseous. Their principal use is, by acting
on the carpo-metacarpal articulations of the
thumb and little finger, which enjoy freer
motion than the intermediate ones, especially
that of the thumb, to oppose these extreme
points of the hand to each other, more or less
increasing its concavity, and thereby giving a
firmer grasp, inasmuch as they adapt the cavity
of the palm to the volume of the body grasped.
The great use of this opposable faculty of the
thumb (which action is the peculiar characte-
ristic of the hand as distinguishing it from the
foot) may be shewn by firmly clenching the fist,
when the thumb, by its combined powers of
opposition and flexion, is made to overlap the
fore and middle, and in some the third fingers,
pressing them firmly against the palm, while,
at the same time, the thenar eminence is
thrown forwards and inwards, meeting them in
the palm, and by abutting against counteracts
their tendency to fly open when a blow is
struck, acting at the same time as a cushion to
deaden the violence of the shock. We here
see, also, the flexion of the fingers modified by
the radial interossei and lumbricales, which,
by their action, throw the fingers radiad, so as
to bring the three outer ones to abut against
the thenar eminence; the little finger is pro-
tected, in like manner, by the hypothenar,
which is thrown forwards and outwards. The

converse modification of the flexion of the
fingers by means of the ulnar interossei may
be seen in the action of the left hand of a
fiddler, where the fingers are flexed and pointed
ulnad to run up the scale.

It only remains for us to give a summary
view of the muscles, extrinsic and intrinsic,
concerned in the motions of the hand. These
motions are flexion, extension, adduction or
motion ulnad, abduction or motion radiad.
First, the flexors of the wrist are six. 1.
Flexor longus pollicis ; 2 and 3, flexor sub-
limis et profundus ; 4, palmaris longus ; 5,
flexor carpi radialis; 6, flexor carpi ulnaris.
The extensors are six. 1, Extensor communis;
2, indicator ; 3, extensor secundi internodii
pollicis; 4 and 5, extensores carpi radiales
longior et brevior; 6, extensor carpi ulnaris.
The last three of the extensors as well as the
last three of the flexors act directly on the wrist ;
the others act first on the phalanges. These
also are the muscles that, in extreme flexion
and extension, call into play the motion that
exists between the two rows of the carpus, the
two former extending, the three latter flexing
the second row upon the first.

The adductors are five. 1. Extensor carpi
ulnaris ; 2, extensor communis ; 3, flexor carpi
ulnaris ; 4, sublimis ; 5, profundus.

The abductors are also five. 1 and 2, Ex-
tensores ossis metacarpi et primi internodii
pollicis; 3 and 4, extensores carpi radiales
longior et brevior ; 5, flexor carpi radialis.

The following table is intended to exhibit at
one view the motions of which the fingers are
capable, and the muscles which effect them.

The movements of the fingers are —

1. Flexion performed by nine.
Flexor longus pollicis.
Flexor sublimis.

Flexor profundus.

Three internal lumbricales.

Three interossei in tern i.

2. Extension by eight.
Three extensores pollicis.
Extensor communis.
Indicator.

Three internal dorsal interossei.

3. Adduction by seven.

Three adductor, flexor brevis, and oppo-
nens pollicis.

Abductor minimi digiti.

Three interossei, viz. posterior indicis,
posterior medii, posterior annularis.

4. Abduction by eleven.
Abductor pollicis.

Adductor et opponens minimi digiti.
Four lumbricales.

Four interossei, viz. abductor indicis, prior
medii, prior annularis, interosseus au-
ricularis.

We thus see that the hand is furnished with
no less than thirty-three muscles, each capable
of acting either singly or in conjunction with
others. The most powerful of these are the
flexors and opposers, both performing actions,
as we have seen, peculiarly adapted for the pre-
hension and retention of bodies.

But there is yet another function in which

REGIONS OF THE HAND.

523

they are the chief agents, and of which the
hand is the principal organ, that of touch,
which may be regarded as a kind of sentinel
by which we ascertain the nature of bodies ;
which without seeing warns the hand from too
closely embracing what may prove hurtful to
itself, or admonishes it to handle gently those
delicate objects that would be destroyed by too
rude a grasp. In the blind this sense, by con-
stant exercise, becomes so perfect as in a great
measure to compensate for the loss of sight.
But by the combination of these two functions
the hand is indeed rendered an organ worthy
of, and admirably suited to the mind of man.
With the one he plans, while through the other
he performs and executes all that administers
to the pleasures, the comforts, and the conve-
niences of life, and that establishes his superi-
ority in the creation.

(F. T. M'Dougall.)

HAND, REGIONS OF THE. (Surgical
Anatomy.) In the consideration of the surgical
anatomy of the hand, we shall commence our
description from an imaginary line encircling
the fore-arm, at a point immediately below the
insertion of the pronator quadratus, or about
half an inch above the radio-carpal articulation.
From this point downwards for about a finger' s-
breadth, the wrist is narrow and flattened like
the fore-arm ; from thence the hand, gradually
expanding, acquires that remarkable breadth
and flatness so necessary to it both as a tactile
and prehensile organ ; it is broadest inferiorly
where it terminates in the fingers. In front,
this region is concave and hairless ; posteriorly,
it is convex and slightly hairy.

In woman, the hand is smaller and more de-
licately shaped ; it is also rounder and smoother,
on account of the greater quantity of subcu-
taneous adipose tissue, softening down the
harsher outline of bone and tendon displayed
in the brawny hand of man.

In order to avoid needless prolixity, we shall
not subdivide this inferior segment of the upper
extremity into the three distinct regions of wrist,
hand, and fingers ; which, indeed, if we were
considering its bony frame-work, would natu-
rally present themselves. But as the soft parts,
with which we have principally to do in the
present article, exhibit no such natural distinc-
tions in these separate parts, and are, for the
most part, common to them all, we shall con-
sider them as constituting one entire region,
which is naturally subdivided into palmar and
dorsal regions.

I. Of the palmar region of the hand. — The
remarkable points on the exterior of this region
are as follows : — Commencing from the pre-
supposed imaginary line, and proceeding down-
wards, we perceive most externally a projection
formed by the united tendons of the short ex-
tensors of the thumb; next in order, proceeding
from without inwards, we notice a hollow, most
visible when the hand is flexed, corresponding
to the radio-carpal articulation, and in which
the radial artery may be felt pulsating imme-
diately before it passes under the tendons we

have just noticed ; bounding this hollow, on its
inside, is a second eminence, formed by the
tendons of the flexor carpi radialis and palmaris
longus, and the projecting crests of the scaphoid
and trapezium ; more internally a second de-
pression, corresponding to the ulnar nerve and
artery, bounded internally by a third eminence,
that of the flexor carpi ulnaris tendon and the
pisiform bone, posterior to which may be felt
the inferior extremity of the ulna and the inter-
val between it and the bones of the carpus.

Lastly, in front of the wrist, owing to the
thinness of the skin in this part of the palmar
region, we perceive a blue network of veins,
from which the median is formed.

More inferiorly, in the palm proper, we notice
externally the thenar eminence, extending from
the crest of the scaphoid to the base of the first
phalanx of the thumb. On the inner side of
the palm is the hypothenar eminence, longer
and thinner, but less prominent than the last ;
it extends from the pisiform bone to the base of
the first phalanx of the little finger. Separating
these prominent parts, and extending from the
inner furrow of the wrist towards the root of
the index finger, is a deep excavation, — the
hollow of the palm ; next may be seen or felt
four elevations, corresponding to the heads of
the four metacarpal bones, about an inch in
front of which the fingers free themselves from
the skin of the palm, which is prolonged over
them for that distance in a manner somewhat
analogous to the web in the foot of a Newfound-
land dog, or other swimming animals. Of the
fingers themselves, the middle is the longest,
the first and third are on a level, the little finger
reaches the level of the last articulation of the
annular, and the thumb terminates about three
lines behind the second articulation of the index ;
the phalangeal articulation of the thumb being
exactly on a level with the metacarpo-phalangeal
union of the same finger.

There are likewise certain lines or furrows
caused by the folding of the skin in flexion of
the hand and fingers, some of which constantly
occur, and are worthy of notice, inasmuch as
they sometimes serve as guides or landmarks to
the surgeon in operating on this region. They
are as follows: two on the wrist; the superior
one, extending between the styloid processes of
the radius and ulna, corresponds to the radio-
carpal articulation. Another, more remarkable,
slightly convex downwards, projecting between
the palmar eminences, separates the wrist
from the hand, and corresponds to the articula-
tion between the two rows of the carpus. In
the palm, one commences from the metacarpo-
phalangeal articulation of the index finger,
which soon bifurcates, one of its divisions
bounding the thenar on its inner side ; the other
runs obliquely across the palm, and terminates
on the upper part of the hypothenar : this in a
measure corresponds to the superficial palmar
arch, having the same obliquity across the palm,
but being three or four lines inferior to it ; these
lines are caused by the opposition of the thumb.
There is yet another line running from the in-
terval between the index and middle fincrers to

524

REGIONS OF THE HAND.

the base of the little finger; this traverses the
hand about two lines above the metacarpo-
phalangeal articulations. Opposite the joints
of the fingers there are also transverse lines ;
the two first have double, the last joint but a
single line ; — an incision made perpendicular
to it would fall about a line above the articula-
tion. Of the middle joint, the superior trans-
verse line is the most constant, and is placed
about half a line above its articulation.

Of the lines corresponding to the first joint
of the fingers, the superior is on a level with
the termination of the interdigital web, and from
ten lines to an inch below the articulation,
excepting that of the thumb, which resembles
the middle joint of the fingers, its line nearly
corresponding to the articulation. There are
many other inconstant folds, or markings of the
skin, in this region, which, to the surgeon, are
of little import, but which present a book of
mystic lore to the gipsy and the cheirornancer,
wherein (when opened by the necessary charms)
they discern the future destinies of all that seek
to be enlightened by them.

We shall now proceed to examine the various
structures found in this region, and, for con-
venience of description, shall consider them as
-constituting the following layers : — 1, skin ;
2, subcutaneous cellular tissue, vessels, and
nerves ; 3, aponeurosis ; 4, deep vessels and
nerves ; 5, muscles and tendons.

1. The skin. — The integument on the front
of the wrist resembles that on the anterior sur-
face of the fore-arm ; but, on reaching the palm,
it suddenly changes its character, and instead of
•the fine, smooth, yielding skin, we find it dense,
resisting, exceedingly vascular, and covered
with a very strong and thick cuticle ; on the
thenar, however, it preserves some degree of
suppleness and elasticity. In those accustomed
to hard manual labour, and in the aged, the
cuticle becomes so thick and callous as to en-
able them to handle even hot coals without
inconvenience ; but in them, from this increased
resistance, and from the difficulty of getting at
matter, or freeing the parts by incisions, inflam-
mations of the palm are the more dangerous.
Corns are sometimes developed at the roots of
the fingers, on the prominences formed by the
heads of the metacarpal bones. There are no se-
baceoifs follicles to be discovered in this region ;
but M. Velpeau thinks, from the fact of the
occasional appearance of variolous pustules on
the front of the fingers, that follicles there exist.
The physical conditions of the skin of the
hand, as to coolness or warmth, as to moisture
or dry ness, often furnish valuable signs in dis-
ease.

2. Subcutaneous cellular tissue is dense and
serrated, more fibrous than cellular, enclosing
in its meshes small rounded pellets of fat. On
the wrist it binds the skin so closely to the
subjacent parts, that, in cases of serous or other
infiltration above this point, the effused fluids
are arrested, and prevented from passing into
the palm of the hand ; also, in very fat and
flabby people, and in young children, a kind of
strangulation is observable at the wrist from

the same cause. On the thenar this layer is
laxer and less compact, permitting the skin to
play freely. On the centre of the palm and
hypothenar it is very dense and fibrous, enclos-
ing larger pellets of fat, binding the skin very
firmly to the palmar aponeurosis and sheaths
of the fingers, towards the extremities of which
it becomes more fatty, increases in thickness,
forming a soft elastic cushion called the pulp of
the fingers. This tissue is the seat of that painful
phlegmonous inflammation, the true whitlow.
The unyielding natureof the thick consistent skin
on the one hand, and of the bones and sheaths
on the other, whereby the swollen and inflamed
pulp, together with its great number of vessels
and the nervous expansion it encloses, are vio-
lently compressed, easily account for the violent
symptoms, and call loudly for the prompt relief
of the strangulation by means of the knife, and
also indicate the great advantage of emollients.

The subcutaneous nerves are few, and derived
from the palmar cutaneous branch of the median
and some terminal branches of the internal and
musculo-cutaneous nerves. The veins are also
veiy few, and give rise to the median, and are
accompanied by the superficial lymphatics.

3. The aponeurosis. — At the wrist the apo-
neurosis, derived from that of the front of the
forearm, is interwoven with and inseparable
from the anterior annular ligament, from the
lower border of which, and from the tendon of
the palmaris longus, the palmar fascia proceeds.
Above the annular ligament the aponeurosis is
attached to the extremity of the ulna, and the
pisiform and the styloid process of the radius ;
it furnishes sheaths to the tendons that do not
pass under the annular ligament, one to the ul-
nar and its nerve, and another to the radial
trunk and its volar branch. The anterior annu-
lar ligament is exceedingly strong, attached
internally to the pisiform and unciform, and ex-
ternally to the scaphoid and trapezium. It con-
sists of two layers, the one superficial, of diver-
gent fibres, derived from the tendon of the
palmaris longus when it exists, or belonging to
the origin of the palmar fascia when it does
not; the other deep, of transverse fibres, con-
tinuous with the fascia of the forearm. It
forms, together with the concavity of the pal-
mar aspect of the carpal bones, a sort of ellipti-
cal ring about two inches in its transverse, and
one inch in its antero-posterior diameter, and
gives passage to the common flexor tendons and
median nerve, which are enveloped by a com-
mon synovial bursa which binds them together,
and terminates in a common cul-de-sac above
and below the ligament; also to the long flexor
tendon of the thumb, which has a distinct
bursa. This ligament, from its great strength,
presents an insurmountable obstacle to the pro-
gress of tumours developed beneath it, forcing
them to protrude on the forearm above the liga-
ment in the hand below it. Thus, when the
common synovial bursa of the tendons is dis-
tended, it forms two tumours, the one above,
the other below the ligament ; and upon com-
pressing the fluid from one the other will be
found to enlarge. Ganglia rarely occur here.

REGIONS OF THE HAND.

525

The annular ligament gives attachment inferiorly
on either side to the muscles of the thumb and
little finger, and in the centre to the palmar
fascia, a dense fibrous layer binding down the
flexor tendons in their passage along the hand.
The palmar fascia is chiefly derived from
the expansion of the palmaris longus, which,
when present, is its tightening muscle. It
is strongest in the palmar hollow, where it
is triangular in shape, its apex at the an-
nular ligament, and is composed of divergent
and longitudinal, interwoven with a few trans-
verse fibres; the latter, becoming gradually
fewer and more scattered, are lost on the
tendons running to the fingers, and some few
are at times continuous with the tendinous
sheaths of the fingers. Near the roots of the
fingers this portion of the palmar fascia divides
into four bands, which subdivide each into two
tongue-like processes, that embrace the heads
of the metacarpal bones, and are attached to
the sides of the first phalanges and the inferior
transverse metacarpal ligament. At this point
of division the transverse fibres are stengthened,
and convert these slits into four distinct fibrous
arches, through which pass the flexor tendons.
Between these arches we find three lesser ones
resulting from the primary division of the fascia.
They transmit the collateral vessels and nerves,
and the lumbricales. This fascia is intimately
connected with the preceding layer anteriorly,
its deep surface covering the superficial palmar
arch, flexor tendons, ulnar and median nerves,
from which it is separated by loose and very
extensible cellular tissue, which permits the
tendons to play freely. This portion of the
fascia presents numerous apertures through
which the deep fat and cellular tissue commu-
nicate with the subcutaneous, and when the
parts beneath are swollen they protrude, form-
ing small hernise, which, getting strangulated in
these apertures, give rise to great pain. It de-
taches from either side two processes, a superfi-
cial and a deep one. The two deep processes
dive deep into the palm, to form the mterosseous
aponeurosis ; of the superficial ones, the exter-
nal, assisted by the tendinous expansion of the
extensor ossis metacarpi, envelopes the thenar
muscles; the internal stronger, and assisted by
the flexor carpi ulnaris expansion, encloses
the hypothenar muscles, and to it is attached
the palmaris brevis. We next meet with the
strong sheaths binding down the flexor tendons
in their passage along the fingers. They are
continuous above with the palmar fascia, by
means of strong detached transverse fibres,
which are prolonged over the tendons as they
pass through the arches of the fascia; laterally
they are firmly attached to the ridges on the
sides of the phalanges. On the bodies of the
two first phalanges these sheaths are very
strong and resisting; but opposite the articula-
tions they become very thin, and are often
wanting; so that the synovial sacs of the ten-
dons are in contact with the subcutaneous layer;
and it is through these spaces that the inflam-
mation in whitlow is propagated to the synovial
membrane and joints. At the last joint of the
fingers they become weak and thin, and are

confounded with the* pulp and periosteum.
They each enclose a distinct elongated synovial
sac, which reaches as far upwards as the fibrous
arch of the fascia, but does not communicate
with the synovial membranes of the joints, en-
tirely enveloping the flexor tendons, lubricating
them, and facilitating these motions in the
sheaths. At the point where the tendon of the
profundus passes through the divisions of the
sublimis, there is a falciform process of the
synovial sheath of considerable strength, at-
taching the tendon of the latter to the first pha-
lanx, so that if the fingers be amputated at the
second joint, the power of moving the first
phalanx will still be retained, though the con-
trary has been stated. We may here likewise
notice that the gradual contraction of the three
last fingers occurring in adults, (crispatura ten-
dinum,} formerly thought incurable, as it was
supposed to be the result of a drying or con-
traction of the tendons, is stated by Baron
Dupuytren to be nothing more than a band or
strip of the palmar fascia, adhering to the
sheath of the tendon, upon the division of
which a complete cure may be effected ; or it
may be caused by a fibrous transformation of
the subcutaneous cellular layer, depriving it of
its elasticity, and causing it to contract, so that
the finger cannot be extended. What favours
this opinion is, that this malady generally oc-
curs in labourers, boatmen, and those whose
avocations necessitate constant flexion of the
fingers, at the same time that firm pressure is
kept up, especially against the roots of the
three inner fingers, as in handling a spade, or
grasping an oar.

4. The vessels and nerves are exposed on
removing the fascia, being immediately under-
neath it. The palmar aspect of the hand being
that of flexion, according to the general rule of
arterial distribution, the principal trunks are
there found; they are the ulnar and radial
arteries, and a branch of the interosseous ac-
companying the median nerve.

The ulnar artery at the wrist lies on the
annular ligament, to the radial side of the pisi-
form bone, where it is covered by the expan-
sions of the flexor carpi ulnaris ; it then curves
towards the mesial line, and crossing the annu-
lar ligament, traverses the palm between the
fascia and the flexor tendons, in a curved direc-
tion towards the centre of the metacarpal bone
of the index finger. In this course it forms an
arch, the convexity of which looks downwards
and inwards, towards the ring and little fingers,
its concavity being turned to the ball of the
thumb. It then inosculates with two branches
from the radial, the superficialis volse, and the
radialis indicis, forming thus the superficial
palmar arch, from the convexity of which pro-
ceed four digital arteries which subdivide into
the collateral branches at about two lines below
the metacarpo-phalangean articulations; they
supply the palmar and lateral surfaces of all the
fingers except the thumb and the radial side of
the index finger. They all run along the sides
of the fingers external to the sheaths, to the
last phalanx, where those of either side coalesce,
forming an arch, from which arise numerous

526

REGIONS OF THE HAND.

branches to supply the pulp of the fingers.
When the artery arrives at the wrist, it sends
off two regular branches, the arteriae carpi ulna-
res anterior et posterior, to the fore and back
parts of the joint. After crossing the annular
ligament, it detaches also a deep communicat-
ing branch, which dips down between the
flexor brevisand abductor minimi digiti, to join
the deep arch from the radial.

The radial artery, just below the styloid
process of the radius, passes round to the back
of the wrist under the two external extensors of
the thumb, to the cleft between the two first
metacarpal bones, where it again passes into
the palm between the heads of the first dorsal
interosseous, and then between the short flexor
and adductor of the thumb, to form with the
communicating branch from the ulnar the deep
palmar arch. In this course it lies upon the
capsular and external lateral ligaments, and
close upon the head of the first metacarpal
bone; it is therefore generally divided in the
amputation of that bone ; but'it would often be
avoided, were the edge of the knife kept close
to the inner side of the bone, as it is carried
down to the joint. Before it curves round the
wrist, this artery gives off the superficial is volae,
a branch which runs over the annular ligament
to unite with the superficial palmar arch; also the
anterior carpal branch, which anastomoses with
the anterior interosseous and corresponding ulnar
branch. At the back of the carpus it detaches
the dorsalis carpi radialis, which inosculates
with the corresponding branch from the ulnar ;
it runs beneath the extensor tendons, supplying
the synovial membrane and the bones of the
carpus ; it also anastomoses with the posterior
interosseous. This branch generally sends off
the metacarpal artery, which forms a kind of
posterior arch across the heads of the metacarpal
bones, that supplies the integuments and inter-
ossei muscles ; — this metacarpal branch some-
times arises from the trunk of the radial. The
only remaining dorsal branches are, the arterise
dorsales pollicis, in general two distinct branches,
but sometimes arising by a common trunk.
They run along the dorsum of the thumb, the
one on the radial, the other on its ulnar side ;
this last sends a branch to the index finger, the
dorsalis indicis. The radial artery then dips
deep into the palm, as before described, and
divides into its three terminal branches : the
first is the magna pollicis, which runs along the
ulnar side of the metacarpal bone of the thumb,
and at its inferior extremity divides into two
collateral branches, which are distributed simi-
larly to those of the fingers. The next branch
is the radialis indicis, which forms the external
collateral artery of that finger; it receives a
branch of communication from the superficial
palmar arch. Lastly, the arteria palmaris pro-
funda ; this runs deeply into the palm, generally
separating the flexor brevis and adductor pollicis
muscles. It crosses the interossei and anterior
part of the superior extremities of the metacarpal
bones ; it is covered by the deep flexor tendons
and lumbricales ; and opposite the fifth meta-
carpal bone inosculates with the communicating
ulnar, — completing thus the deep palmar arch,

the convexity of which is towards the fingers;
and it gives four or five regular branches, which
supply the interossei, and at the clefts of the
fingers anastomose with the digital branches.
This arch is less oblique, and farther from the
fingers, than the superficial one.

Thus we see that the disposition of the arteries
of the hand is peculiar, and is somewhat analo-
gous to that of the venous system generally, —
viz. that they are divided into a superficial and
deep set. The question naturally occurs, whe-
ther it may not be for the same cause, viz. that
when pressure obstructs the superficial vessels,
the deep may still carry on the interrupted cir-
culation? In the hand, as we have seen, the
communications between the deep and super-
ficial arches are frequent and free, while we
daily experience with what violent and continued
pressure the circulation through the superficial
arch is liable to be interrupted.

The varieties of the arteries of the hand are
numerous : sometimes the radial predominates,
at other times the ulnar, in the share they respec-
tively take in supplying the hand; they are
always in an inverse ratio; and if both are small,
then the artery of the median nerve derived
from the interosseous is proportionably large.

From the constant call for vigorous and rapid,
as well as sustained and powerful action, the
hand, with the exception of the tongue, is the
most vascular of the voluntary locomotive mem-
bers of the human body. The communications
between its arteries are so numerous and free, as,
in cases of simple wounds of this region, fre-
quently to prove a ^source of great embarrass-
ment to the surgeon, and, in unskilful hands, of
danger to the patient. Wounds of the integu-
ments of the palm often bleed profusely, and
are liable to secondary haemorrhage. This may
in some measure be accounted for by the pecu-
liar density of the cellular tissue and skin, and
its intimate connection with the subjacent fascia,
which, as well as the numerous branches given
off from the divided vessels, prevent their re-
traction, nor can a coagulum easily form around
them ; they are not generally vessels that require
a ligature, (excepting in cases similar to one
related by M. Velpeau, where the arteries of
the hand were in a varicose state, and of an
enormous size,) but where ordinary means fail,
plugging the wound, the continued application
of cold, and a tightish bandage up to the
shoulder, in order to moderate the circulation
in the whole limb, will usually stop even very
severe bleedings. If these means should not
succeed, and no large divided vessels can be
seen in the wound, the surgeon must tie one or
even both arteries above the wrist. The inos-
culations with the interosseous will sometimes
even then allow the bleeding to continue, espe-
cially in cases where the median branch is
large, or helps to form the arch ; but pressure
and cold will then soon stop the remaining
haemorrhage.

Veins. — The deep ones accompany their
arteries ; the superficial veins are very few on
the palm.

The lymphatics accompany the veins.

The nerves of this region are superficial and

REGIONS OF THE HAND.

527

deep : the former have been already noticed ;
the latter are the median and ulnar. The first
passes under the annular ligament with the
flexor tendons; it then divides into five branches,
behind the superficial palmar arch. The first,
or most external of these branches, supplies
the short muscles of the thumb ; the second
sends one or two deep branches down to the
interossei, to communicate with the deep palmar
branch of the ulnar nerve ; it then finishes on
the outer side of the thumb; the remaining
three branches soon bifurcate, and are distri-
buted to the ulnar side of the thumb, to both
sides of the index and middle, also to the radial
side of the ring finger ; giving likewise a branch
to each corresponding lumbrical muscle.

The ulnar nerve passes over the annular liga-
ment to the internal and posterior side of its
artery ; while passing over the ligament, it sends
the cutaneous branch to the skin on the hypo-
thenar, and then it divides into three branches :
first, the deep palmar branch, which accom-
panies the communicating branch of the artery,
and behind the deep palmar arch unites with
the branch sent from the median to supply the
deep muscles ; the next branch supplies the
ulnar side of the little finger and its muscles ;
while the remaining branches supply the col-
lateral nerves not furnished by the median, to
the radial side of the little, and the ulnar side
of the ring fingers. All these collateral nerves
accompany the corresponding arteries along the
sides of the fingers, giving numerous branches
in their course that terminate in the skin ; and
on the last phalanx they divide into two branches,
a dorsal and palmar : the dorsal, or ungual
branch, is lost in the skin, under the nail ; and
the palmar is expanded in the pulp of the
fingers. It is remarkable that the nerves of the
opposite sides of the fingers never anastomose.

The muscles and tendons with which the
hand is pre-eminently endowed, lastly present
themselves for our consideration. In the upper
part of this region, or in front of the wrist,
there are scarcely any muscular fibres, except-
ing a small portion of the origins of the thenar
and hypothenar muscles ; and sometimes the
lower border of the pronator quadratus reaches
as far, or a little below the imaginary line wre
have marked out as the superior boundary of
this region. But we have no lack of tendons
in this part; for we here find an assemblage of
them more numerous, and more tightly packed,
than in any other part of the body ; they are
also invested by synovial sacs, and pass through
the carpal ring, which was described in speak-
ing of the annular ligament in which they are
closely bound down. There are, however, some
that do not pass through this ring, and they are
the following : — Most externally is the tendon
of the supinator longus, which terminates by
being inserted into the radius at the upper
boundary of this region ; then the tendons of
the extensores ossis metacarpi, and primi inter-
nodii pollicis. running in the most external
groove in the radius, which is converted into a
sheath for them by a process of the posterior
annular ligament. The radial artery passes

under these, separating them from the joint in
its passage to the back of the wrist.

More internally we have the tendon of the
flexor carpi radiafis passing into the palm, be-
hind the external reflected portion of the annu-
lar ligament, in a canal destined for it in the
scaphoid and trapezium ; the next tendon is
that of the palmaris longus, which here begins
to expand on the anterior surface of the annular
ligament, to which it is also attached; and
lastly, we find the flexor carpi ulnaris tendon
implanting itself into the pisiform bone. This
tendon, and those of the short extensors of the
thumb, form the lateral boundaries of this
region, dividing it from the dorsal.

All the other tendons from the front of the
fore-arm pass through the carpal ring; they
are nine in number : — Four of the flexor subli-
mis ; four of the flexor profundus, — these are
all bound up in a common synovial sheath,
along with the median nerve; the remaining
tendon, that of the flexor pollicis, is situated
more externally, and has a distinct synovial sac.
All these tendons, after emerging from under
the annular ligament, diverge towards the differ-
ent fingers to which they are destined. In the
palm they are placed beneath the aponeurosis,
and lie upon the palmar interossei and the
adductor pollicis.

As the muscles of the palm have already
been described, (see HAND, MUSCLES OF,) we
shall not notice them further than merely to
observe, that the intrinsic muscles of the thumb
and little finger constitute the external and in-
ternal regions of the palm, which they almost
solely occupy ; while the middle region, or
hollow of the palm, is occupied not only by
the remaining intrinsic muscles, (the interossei
and lumbricales,) but also contains the tendons
just described, with their synovial sheaths, as
well as the principal vascular and nervous
trunks of the hand. Wounds are therefore more
dangerous in the middle of the palm than on
either the external or internal regions, which
are constituted principally of muscle, having
but a thin aponeurosis and no important vessels
or nerves. It is also worthy of remark, that
the short muscles of the thumb, especially the
abductor, flexor brevis, and adductor, though
they act but indirectly on the first metacarpal
bone, present a serious obstacle to its dislocation
forwards ; their action tending to throw its base
backwards, whilst, by their bulk and tension,
they repel its attempts to slip forwards.

Having now examined all the soft parts on
the palmar region, as nearly as possible in the
order in which they would have been exposed
by the dissector, we proceed to the second
division of our subject, and shall consider the
various layers of the dorsal region in similar
order.

II. The dorsal region of the hand is convex
and irregular; the veins are large and promi-
nent. When the hand is extended the extensor
tendons stand out in strong relief, converging
at the wrist; and when flexed the heads of the
metacarpal bones and phalanges protrude. The
other prominent external characters of this

528

REGIONS OF THE HAND.

region are, at the superior and external part,
when the thumb is extended and abducted,
au elongated depression, bounded externally
by the two short extensor tendons of the thumb,
and internally by its long extensor and the
tendon of the extensor carpi radialis longior.
In this depression the pulsation of the radial
artery may be felt, also the heads of the two
first metacarpal bones : internally and about
the same level there is a hollow corres-
ponding to the union of the wrist and hand ;
and at this point we can feel the tendon
of the extensor carpi ulnaris and the sty-
loid process of the ulna. When the thumb is
adducted the first dorsal interosseous projects
considerably. The fingers appear longer on
their dorsal aspect, the interdigital web that
was noticed on their palmar surface being here
wanting.

1. The skin is very loose and thrown into
transverse folds ; opposite the two last joints of
the fingers may generally be seen three or more
transverse furrows; the middle one is the
deepest and most constant, and an incision
made about a line and a half below it will hit
upon the articulation. It resembles that on
the back of the fore-arm, but it gradually
thickens at the sides as it approaches the palmar
surface. Hairs and sebaceous follicles are
most abundant on the ulnar side of the back of
the hand and on the first phalanges. On the un-
gual phalanx, the skin, as it approaches the nail,
becomes tighter and glabrous, extends for about
two lines over the root of the nail, and is then
reflected back, so as to be continued over its
anterior surface to its free border, where it
becomes continuous with the skin of the pulp
of the fingers. It is in this portion of the skin
about the roots of the nails that the false whit-
low, called by the French tourniole, takes
place. It is an inflammation more of an
erysipelatous than a phlegmonous nature, some-
times attacking several fingers successively or
at once, therein differing from the true whitlow,
which is generally confined to one finger.
Warts also frequently occupy the skin of the
dorsum of the fingers, especially in those that
have to perform hard manual labour.

2. The subcutaneous layer is very lax, serous
infiltration easily taking place; it contains no
pellets of fat like that of the palmar surface.

The veins are subcutaneous, large and nu-
merous; all the large veins of the hand being
on its dorsal surface, the venous circulation is
not interrupted by the effort of prehension.
On the back of the fingers they form a com-
plete net-work, which gives rise to the dorsal
collateral veins of the fingers. At the inter-
osseous spaces these unite as the arteries di-
vide, and then proceed towards a kind of dorsal
venous arch, the concavity of which is upwards,
and from which arise larger branches; these,
in conjunction with one from the little finger
called the vena salvatella, and another from the
thumb called the cephalic, form the basilic and
cephalic veins described in the fore-arm. (See
FORE-ARM.) Some people prefer being bled
on the back of the hand, but, owing to the

laxity of the skin and subcutaneous layer, con-
siderable extravasation of blood is apt to take
place. The subcutaneous nerves, derived from
the dorsal branch of the ulnar, and the ter-
minal branches of the musculo-spiral accom-
pany the veins, as also do the lymphatics.

3. The apuneurosis is continued from that of
the back of the fore-arm ; it is strengthened
across the back of the wrist by strong parallel
oblique fibres, forming a band of nearly an
inch in breadth; which extends obliquely down-
wards over the extensor tendons from the sty-
loid process of the radius to the internal lateral
ligament of the wrist.* It sends down strong
processes between the tendons that convert the
grooves in the back of the radius and ulna into
sheaths, which are as follows: — 1st, that noticed
on the palmar region for the short extensors of
the thumb ; 2d, for the radial extensors; 3d, for
the long extensor of the thumb; 4th, for the
extensor communis and indicator tendons;
5th, for the extensor minimi digiti ; 6th and
last, for the extensor carpi ulnaris. The meta-
carpal aponeurosis is very thin and split into
two layers ; the one separates the subcutaneous
layer, vessels, and neives from the tendons ;
the other covers the dorsal interossei, isolating
them from the tendons.

4. The nerves are, externally, the radial,
which sends one branch, that, bifurcating, sup-
plies the thumb and radial side of the index
finger ; and another, which in like manner fur-
nishes the inside of the index and the middle
finger. Internally the posterior branch of the
ulnar supplies the two remaining fingers. These
branches receive frequent communicating ram uli
from the anterior collateral nerves.

5. Tendons and muscles. — The former are
less numerous on this region than on the pal-
mar ; the order in which they cross the wrist
was mentioned in describing the aponeurosis.
If the divisions of the extensor communis be
enumerated, they are twelve in number; four
of these are inserted at the base of the meta-
carpal bones of the thumb, index, middle, and
little fingers ; they are the extensor ossis meta-
carpi pollicis, extensores carpi radiales, and
extensor carpi ulnaris. The other tendons
proceed onwards to the phalanges. Those of
the common extensor are flattened and riband-
like; the three inner ones communicate with
each other, while that going to the index is
free. Opposite the metacarpo-phalangean arti-
culation these tendons narrow and thicken,
sending an expansion to either side of the
articulation: they again flatten on the first
phalanges, where they receive the tendons of
the lumbncales and interossei. At the articu-
lation of the first and second phalanges they
divide into three portions: a middle one, that
is inserted into the superior extremity of the
second phalanx ; and two lateral ones, that run
along its sides, reunite at its inferior end, and
are implanted into the upper part of the ungual

* Generally called the posterior annular liga-
ment.

ORGAN OF HEARING.

529

phalanx.* The remaining tendons of the index
and little fingers are implanted into the pha-
langes of those fingers with those of the
common extensor : those of the thumb are
inserted separately. Having no sheaths, these
tendons are firmly attached by means of a
membranous expansion to the bones to prevent
them slipping aside, nor have they here any
synovial membranes, and are therefore in con-
tact with those of the joints; but as they pass
through the sheaths in the posterior annular
ligament, they are all provided with synovial
sacs. The largest is that of the extensor com-
munis and indicator; they are less complex
than those of the palmar region, and their
inflammation less formidable and not so pain-
ful. The occurrence of ganglia is here very
frequent. They sometimes attain a large size
and produce considerable inconvenience. The
puncture of them is not so dangerous here as
in the palmar region.

6. Arteries. — The course of the radial ovei;
the back of the hand has been already noticed ;
its metacarpal and carpal branches run across
the wrist beneath the extensor tendons, unite
with the posterior carpal branch of the ulnar,
forming a kind of dorsal arch, from which pro-
ceed the interosseous and perforating branches,
to communicate with the deep arch ; also the
dorso-digital branches, one to either side of the
fingers.

The bones and ligaments forming the firm,
light, and compact skeleton of the hand have
been elsewhere described. See article HAND,

BONES AND JOINTS.

In the amputation of the metacarpal bone of
the thumb, which is easily performed at its
articulation with the trapezium, the edge of the
knife should be kept close to the ulnar edge of
the bone, in order, if possible, to avoid wound-
ing the radial artery as it traverses the inter-
osseous space. The metacarpal bone of the
little finger may also easily be removed by an
operation similar to that practised for the
thumb; the articulating surfaces are nearly
plane and inclined obliquely upwards and
inwards. Disarticulations may also be per-
formed of the other metacarpo-carpal joints;
but the operations are very difficult and em-
barrassing, owing to the irregularity of the
articular surfaces and their close connexions
with each other, and in removing them singly
a much neater and easier plan is, if their
upper extremities are sufficiently sound, to saw
through them in an oblique direction.

In amputating at the phalangeo-metacarpal
articulations the flap is, if possible, made on
the palmar surface. At the first joint of the
fingers two flaps are preserved by making two
semilunar incisions, which extend from the
head of the metacarpal bones to the termination
of the commissure of the fingers, meeting be-
hind and before at the joint, which is an inch
above. They may all be amputated together
when a single flap is made on the palmar surface
terminating at the line in the skin that bounds

* It is not uncommon for these tendons to send a
slip to the superior extremity of the first phalanx.
VOL. II.

the commissure. In amputating at the other
joints of the fingers it is necessary to recollect
the marks, before alluded to when speaking of
the skin, and to divide the lateral ligaments
before entering the joints.

( F. T. M'Dougall.)

HEARING, ORGAN OF. The ear (in the
wide acceptation of the term). Organon auditus
s. auris. — Fr. L'organe de Touie ou Voreille.
Germ. Das Gehororgan oder das Ohr. — As
the apparatus of vision naturally admits of
being divided into two parts, viz. the eye-ball
and its appendages, so we can distinguish in
the apparatus of hearing a fundamental organ,
and parts accessory to the perfect performance
of its function. The fundamental organ of
hearing is what is commonly called the interna I
ear, or from the complexity of its structure, the
labyrinth. The accessory organs consist of the
middle ear or tympanum and external ear.*

If we extend our observations to the animal
series, and trace the apparatus of hearing along
the descending scale, we shall find that the
accessory parts gradually disappear, and that
the sense of hearing comes at last to have for
its organ merely a representative of the laby-
rinth in the higher animals. This part even,
having laid aside much of its complicated
structure, presents itself under the form simply
of a membraneous pouch containing a fluid,
with a calcareous concretion suspended in it,
on which the auditory nervous filaments are
expanded.

The labyrinth being in the apparatus of hear-
ing exactly what the eye-ball is in that of vision,
may be distinguished by the name of ear-bulb.
The ear-bulb, like the eye-ball, consists of a hard
external case, in the interior of which are con-
tained membraneous and nervous parts and
humours. The accessory parts of the apparatus
of hearing have also their prototypes in the
accessory organs of the apparatus of vision.

The different parts of the apparatus of hear-
ing are situated in the interior and on the sur-
face of the temporal bone. See the description
of the temporal bone in the article CRANIUM.

I. — THE EAR-BULB, or fundamental organ of
hearing. ( Bulbe auditif] Breschet.)

In man and the higher animals, the hard ex-
ternal case of the ear-bulb is of bone, and is
called the osseous labyrinth. The soft textures
contained in its interior bear the name of mem-
braneous labyrinth. The interior of the osseous
labyrinth, which we may with Breschetf call
the labyrinthic cavity, is not completely filled
by the membraneous labyrinth ; the remaining
space is occupied by a limpid watery fluid.

1 . The osseous labyrinth (labyrin th us osseus ;
Fr. Labyrinthe osseux ; Germ. Das knocherne
Labyrinth.} — The osseous labyrinth presents
three compartments, distinguished by the names

* Haighton, in Memoirs of the Medical Society
of London, vol. iii. p. 7. London, 1792.

t Recherches anatomiques et physiologiques SHT
1'oreane del'ouie et sur 1'audition, &c. chap. i. s. x.
Paris, 1836.

2 N

530

ORGAN OF HEARING.

of vestibule, semicircular canals, and cochlea.
The semicircular canals and cochlea do not com-
municate immediately with each other, but only
mediately through the vestibule. The latter
may be considered the principal compartment.

The osseous labyrinth is imbedded in the
substance of the petrous portion of the temporal
bone, from the compact texture of which it is,
in the adult, scarcely to be distinguished. In
the early periods of life, however, its walls con-
sist of a hard but brittle osseous substance,
around which is the then less compact tissue of
the petrous bone. Hence it is in a young bone
only, and that by means of some little prepara-
tion, that the external form of the osseous laby-
rinth can be well demonstrated.

Of the compartments of the osseous laby-
rinth, the vestibule lies in the middle, the semi-
circular canals behind it, and the cochlea in
front.

¥i§. 232.

The exterior of the osseous labyrinth of the left side.
Natural siste.

a. Oval or vestibular fenestra ; b. round or
cochlear fenestra j c. external or horizontal semi-
circular canal ; d. superior or anterior vertical se-
micircular canal; e. posterior or inferior vertical
semicircular canal ; /. the turns of the cochlea.

The vestibule, (vestibulum ; Fr. le vestibule ;
Germ, der Vorkof.) — The vestibule is an irre-
gularly shaped cavity, the diameter of which
from above downwards, as also from behind
forwards, may be stated to be about one-fifth
of an inch. The distance between its inner
and outer wall is somewhat more than one-
tenth of an inch. In an anatomical sense we
can distinguish in it three horns, one of which
is towards the anterior and lower part, another
towards the posterior and lower part, whilst
the third composes the upper part of the vesti-
bular cavity.

The anterior and lower horn leads by an
oval opening directed forwards and downwards
into the vestibular scala of the cochlea. This
opening is called the vestibular orifice of the
cochlea, osteum s. apertura scal(B vestibuli
cochlea. The posterior and lower horn of the
vestibule corresponds to three of the orifices of
the semicircular canals ; the upper horn to
the other two orifices.

At the under part of the inner wall of the
vestibule, within the limits of its anterior horn
and to the inside of the vestibular orifice of the
cochlea, is a hemispherical depression, Jovea
hemispherica s, nub-rotunda. Its bottom, which
corresponds to the posterior part of the lower
depression at the bottom of the internal audi-
tory meatus, presents a sieve-like spot, macula
cribrosa, that is, it is perforated by minute
apertures for the passage of filaments of the
auditory nerve. On the upper wall of the ves-
tibule, bordering the upper margin of the hemi-

spherical fossa and within the limits of the
upper horn, is another depression, of an oval
shape, which is known by the name of fovea
hemi-elliptica. The hemispherical and hemi-el-
liptical depressions are separated by a ridge or
pyramidal eminence, eminentia pyramidalis,
pervaded by small canals for the passage also
of nervous filaments. On the inner wall of the
vestibule, a little in front of the orifice common
to the two vertical semicircular canals and
within the limits of the posterior horn, there is,
bordering on the hemi-elliptical and hemisphe-
rical depressions, below the former and behind
the latter, another very small depression or
sulcus, fossa s. cavitas sulciformis, which leads
• upwards and backwards to a small oblique
orifice, that of the aqueduct of the vestibule,
osteum internum aqueductus vestibuli. At the
middle of the inner wall of the vestibule, where
the boundary lines of these three depressions
meet, there is a slight eminence.

The inner wall of the vestibule corresponds
to the bottom of the internal auditory meatus,
and is pervaded by small canals, some of which
have been already mentioned, for the passage
of fibrils of the auditory nerve and of blood-
vessels.

In the outer wall of the vestibule there is an
oval, or rather a kidney or bean-shaped hole,
csiiledjbramen ovale, s. 'fenestra ovalis, s. fenes-
tra vestibuli. The long diameter of this aper-
ture, which is about one-tenth of an inch or
perhaps a little more, is directed from behind
forwards. Its vertical diameter is about half
that of its long diameter. The upper part of
the circumference of the hole is arched up-
wards, the lower part is slightly inclined in the
same direction. The margin of the vestibular
fenestra is turned in towards the vestibule.
Viewed from the tympanum, into which it
opens in the macerated bone, the vestibular
fenestra appears situated at the bottom of a
fossa, which was called by Cotugno pelvis
ovalis. In the recent state the vestibular fene-
stra is closed in by the base of the stapes.

The semicircular canals, (canales semicircu-
lares ; Fr. les canaux semicirculaires ; Germ, die
Bogengange oder halbcirkelformigen Candle.)
These are three canals, which, describing more
than the half of an irregular circle, open at each
of their extremities into the vestibule ; hence,
if it was not for the circumstance that two
unite by one of their extremities to form a
common short canal, there would be in the
vestibule six orifices of semicircular canals, in-
stead of the five only which exist. The calibre
of these canals is about one-twentieth of an inch
in the direction from the concavity to the con-
vexity of their curve ; in the opposite direction
they are somewhat compressed, so that a trans-
verse section, instead of presenting a round
orifice, presents an elliptical one. The semicir-
cular canals are wider where they open into the
vestibule, but especially so at one of their ex-
tremities, which presents a dilatation in the
form of a bulb, called ampulla or ampullary
sinus, sinus umpullaceus.

Two of the semicircular canals occupy a
vertical position and one of them a horizontal.

ORGAN OF HEARING.

531

Of the vertical, one is anterior and superior,
the other posterior and inferior. The horizon-
tal is ejitemal.

Superior vertical semicircular canal, canalis
semicircularis verticalis superior. The superior
vertical semicircular canal has its arch directed
upwards, and its extremities, which are more
widely divergent than those of either of the
other two semicircular canals, downwards. Fol-
lowed from its outer extremity, it describes its
curve from without and upwards, then down-
wards and inwards, with an inclination from
before backwards, — in a word, across the petrous
bone. The convexity of the curve of this semi-
circular canal can always be recognized on the
upper surface of the petrous bone. The con-
cavity of it is free in the foetus and in the adult
of some of the lower animals, as the dog, hare,
&c.

The inner extremity of the superior vertical
semicircular canal and the upper extremity of
the posterior vertical unite to form a common
canal, canalis communis, which is about one-
eighth of an inch long, and somewhat wider
than either of the two which unite to form it.

Posterior vertical semicircular canal, canalis
semicircularis verticalis posterior. Leaving the
common canal, the posterior vertical semicircu-
lar canal describes its curve parallel to the
inner and posterior surface of the petrous bone,
perpendicularly from above backwards, then
downwards and forwards. The convexity of
the curve is thus directed backwards and
slightly outwards, its extremities forwards and
inwards.

Horizontal semicircular canal, canalis semi-
circularis horizontalis. This is the shortest of
the three canals ; traced from its anterior extre-
mity, which is close to that of the superior ver-
tical, it curves outwards and backwards, then
inwards and forwards. Its convexity is out-
wards, its extremities directed inwards.

We described in the vestibule three horns,
into the posterior and into the superior of
which the semicircular canals opened. In the
superior horn is observed the orifice of the ex-
ternal extremity of the superior vertical semi-
circular canal, and immediately below that and
above the fenestra vestibuli, the orifice of the
anterior extremity of the horizontal semicircular
canal. Both of these orifices are dilated into
ampullae. In the posterior horn is the orifice
of the canal common to the two vertical semi-
circular canals. Below and in front of this
orifice is the opening of the inferior extremity
of the posterior vertical semicircular canal.
Above the latter and immediately outside the
former is the opening of the posterior extremity
of the horizontal. Of all these orifices in the
posterior horn, that of the lower extremity of
the posterior vertical semicircular canal is the
only one which is dilated into aij ampulla.

There are thus three ampullary dilatations,
one at the outer extremity of the superior verti-
cal semicircular canal, a second at the anterior
extremity of the horizontal, and the third at the
lower extremity of the posterior vertical. In
the lower and anterior wall of the ampullary
sinus of the posterior vertical semicircular canal

is a small sieve-like spot indicating the entrance
of nervous filaments.

The cochlea, (cochlea; Fr. le lima$on; Germ.
die Schnecke.)— The cochlea does not exist in
all its perfection except in the Mammifera. In
birds it is in a very rudimentary state, but it is
easy to trace parts analogous to what we find
in the Mammifera. In regard to frequency of
occurrence in the animal series, the cochlea
does not stand next to the semicircular canals ;
the tympanum is found in a greater number of
animals.

The cochlea forms the anterior part of the
labyrinth, and is, perhaps of all the parts of
the ear, that of which it is the most difficult to
give, either by descriptions or delineations, a
correct idea. If we can figure to ourselves a
tube tapering towards one extremity where it
ends in a cul-de-sac, and coiled, like the shell
of a snail, round an axis or central pillar ; and
if we suppose this tube subdivided into two
passages by a thin partition running throughout
its length, and of course spirally round the
axis, we shall have some conception of the
disposition of the cochlea.

The tube of which the cochlea is composed,
canalis spiralis cochlea, is about an inch and a
half long, about one-tenth of an inch in dia-
meter at its commencement, and about one-
twentieth of an inch at its termination. It
describes two turns and a half, and that in a
direction from below upwards — from left to
right in the right ear, and from right to left in the
left ear. The apex of the coil, which is also the
apex of the tube itself, is directed forwards and
outwards. The commencement of the first
turn of the cochlea forms an eminence towards
the cavity of the tympanum, called the pro-
montory. The second turn lies at its com-
mencement within the first, and only towards
its termination rises decidedly above the level
of it. By the base of the tube the cochlea is
connected with the vestibule. The cul-de-sac
at the apex forms a sort of vaulted roof called
cupola.

The axis, or central pillar, modiolus s. colu-
mella cochlete. The first turn of the cochlea
takes a wider circular sweep than the rest, a
sweep having an average diameter of a quarter
of an inch, and is separated from the second
turn by the interposition of a soft bony sub-
stance, which extends also a little way between
the second and third. The axis, or central
pillar, as has been pointed out by Ilg,* is
nothing more than the internal walls of the
tube of the cochlea and the central space
circumscribed by their turns, in which space
the filaments of the cochlear nerve, running in
small bony canals, are contained. Now in con-
sequence of the wide sweep the first turn of
the cochlea takes in comparison with the rest,
the axis is very thick, about one-seventh of an
inch, where it is surrounded by the first turn,
and rapidly becomes thinner from the second
onwards to its termination. The last part of
it is in fact formed merely by the fold which

* Einige anatomische
Prag. 1821, p. 7.

Beobachtungen, etc.
2x2

532

ORGAN OF HEARING.

the internal wall of the tube of the cochlea ne-
cessarily forms where it bends abruptly ut the
last turn. This last part of the axis, viewed
from the cavity of the second turn of the tube,
has a funnel-like appearance, the wide mouth
corresponding to the cupola; hence it is called
infundibulum or scyphus. But viewed from the
last turn, the so-called infundibulum is a mere
free edge which proceeds directly to be con-
founded with the walls of the cochlea. But
all this, if the disposition of a snail's shell, or
a tube coiled round be rightly conceived, is
understood of itself.

Exposed by the removal of the outer walls
of the cochlea, the axis is somewhat like the
common pictorial representations of the tower
of Babel. It has a spongy porous appearance.
It is pervaded by numerous small canals which
run from its base onwards to orifices on its
sides, corresponding to the spiral lamina, and
transmit into the cochlea the ramifications of
the cochlear branch of the auditory nerve and
bloodvessels. The outermost of the canals are
the shortest; towards the interior they gradually
become longer, and there is one canal in parti-
cular wider than the rest, which runs through-
out its whole length ; it is called tubulus cen-
tralis modioli, and opens at the so-called in-
fundibulum.

The base of the axis corresponds to the an-
terior part of the inferior depression at the
bottom of the internal auditory meatus, and
presents the commencing orifices of the small
canals just mentioned, arranged in a spiral
manner corresponding to the turns of the coch-
lea, tructus spiralis foraminulentus of Co-
in gno.*

Spiral lamina and scala of the cochlea. —
The passages into which the tube of the coch-
lea is subdivided are called scala, and the par-
tition lamina spiralis.

The spiral lamina is partly bony, partly
membraneous; but as we are describing the
osseous shell of the labyrinth only, it is with
the bony part alone we have at present to do.
The bony part of the spiral lamina, zonula ossea
lamina spiralis, is coiled round the axis or cen-
tral pillar of the cochlea like the stairs in a
spiral staircase. The internal or central margin
of the bony spiral lamina is inserted on the
axis. Its peripheral margin is free in the dry
bone, so that the two scalae are not found com-
pletely separated from each other, as in the re-
cent state, when the membraneous extension of
the spiral lamina exists. At the place where
the spiral lamina is inserted on the axis, there
is a sort of canal all round, which has been
specially described by Rosenthalf under the
name of canalis spiro.lis modioli.

The spiral lamina commences with a bend
or sweep upwards and forwards at the base of
the cochlea, below the hemispherical depres-
sion of the vestibule and opposite the bridge of
bone which separates the vestibular fenestra

* De aquediictibus auris humanae internae ana-
tomica dissertatio, s. xxiv. pp. 36—38. Viennae,
1774.

t Ueber den Ban der Spindel im menschlichen
Ohr. In Meckel's Archiv. Bd. viii. p. 75.

from the cochlear fenestra. Its broadest part,
which is about the middle of the first turn of
the cochlea, is about one-twentieth of an inch.
Towards the summit of the cochlea it insen-
sibly contracts, and ceasing to be connected
to the axis, where the latter presents the free
margin already mentioned, terminates at the
commencement of the third turn in a curved
hook-like point. This hook, hamulus lamina
spiralis, has a free concave margin towards the
axis, and a convex margin, which latter, how-
ever, like the rest of the peripheral margin of
the bony spiral lamina, is not free in the recent
state, but is continuous with the membrane
which completes the partition.

In consequence of the above mode of termi-
nation of the bony spiral lamina by means of
a free margin towards the axis of the cochlea,
an opening of communication is left, even in
the recent state, between the two scalae of the
cochlea. For this opening, which was called
by Cassebohm* canalis scalarum community we
adopt from Breschetf the name helicotrema.l

The bony spiral lamina consists of two thin
plates of bone, between which run numerous
small canals from the central margin of the
lamina to its peripheral — the continuation of
those already described in the axis, and which
therefore bend at a right angle in passing from
the axis into the spiral lamina. At the free
edge of the osseous part of the spiral lamina,
the two plates of bone are intimately incorpo-
rated. This part of the bony spiral lamina,
which is more delicate, denser, whiter, more
transparent, and, in the recent state, more
elastic than the rest, is what Breschet calls the
middle zone. The surface of the spiral lamina
corresponding to the tympanic scala is much
marked with striae running from the inner
margin to the outer. The surface correspond-
ing to the vestibular scala is less striated.

Of the two scalae of the cochlea, one, scala
tympani, communicates with the cavity of the
tympanum through the fenestra rotunda or
cochlear fenestra, which however, in the recent
state, is closed by a membrane; the other,
scala vestibuli, opens by an oval orifice freely
into the vestibule, and it is only by means of
the communication which the tympanic scala
has with the vestibular scala through the heli-
cotrema that the former communicates with the
rest of the labyrinthic cavity. The tympanic
scala is wider at the commencement than the
vestibular, which on its part again is larger
toward the termination. Near the feneslra ro-
tunda there is in the tympanic scala a very
minute orifice, that of the aqueduct of the
cochlea. We shall return to the spiral lamina,
the scalae of the cochlea, and the mechanism of
the helicotrema, when speaking of the mem-
brane lining the labyrinthic cavity.

The aqueducts. — What are called the aque-
ducts are two canals of very minute calibre,
opening by one extremity in the labyrinthic

* Tractatus quintus anat. de aure humana, etc.
Hal* Magd. 1735, s. 194, p. 12.
t Op. cit. s. xiv.
t E?u£, f Xirot, where, and Tp»/na, foramen.

ORGAN OF HEARING.

533

cavity, and by the other on the surface of the
petrous portion of the temporal bone. They
are generally associated with the name of Co-
tugno,* who, though not their discoverer, was
the first to give a complete description of them.
One, called aqutductus vtstibuli, communicates
with the vestibule ; the other, aqueductus coch-
letf, with the tympanic scala of the cochlea.

The internal orifice of the aqueduct of the
vestibule is observed to commence by a groove
or sulcus, the sulciform depression already de-
scribed in the vestibule, immediately below
and in front of the opening common to the two
vertical semicircular canals. From this the
aqueduct turns itself round the inner wall of
the common canal, and then follows a course
downwards and backwards. Gradually widen-
ing, it opens under that sort of osseous scale
observed a little behind the middle of the pos-
terior and inner surface of the petrous bone,
just above the jugular fossa ; towards the latter
there is usually a groove running on the surface
of the bone from the orifice of the aqueduct.
The length of the course of the aqueduct of
the vestibule is about one-third of an inch.

The aqueduct of the cochlea commences by
a very small orifice in the lower wall of the
scala tympani immediately before the fenestra
rotunda. It proceeds downwards, inwards,
and forwards, in the inner wall of the jugular
fossa of the temporal bone, and widening in
its course it opens at the bottom of that tri-
angular pyramidal depression, situated towards
the middle of the edge which limits the inner
and inferior surfaces of the petrous bone, and
below the internal auditory meatus. The
length of its course is about a quarter of an inch.
The aqueduct of the cochlea is very wide in
the pig. Of the aqueducts we shall observe
farther in speaking of the membrane lining
the labyrinthic cavity.

Fig. 233.

The labyrinthic cavity of the riyht side, magnified
two diameters.

a. superior horn of the vestibule ; b. posterior
and inferior horn ; c. anterior and inferior horn
leading into the cochlea ; rf. hemispherical depres-
sion ; e. hemi-elliptical depression ; /. pyramidal
elevation between the two having a porous sieve -
like appearance from being pervaded by canals for
the passage of nervous filaments ; g. superior
vertical semicircular canal; h. its ampullary dila-
tation ; t. posterior vertical semicircular canal;
k. its ampullary dilatation; /. canal common to

the superior and posterior vertical semicircular
canals ; m. orifice by which the common canal
opens into the vestibule ; n. horizontal semi-
circular canal; o. its ampullary dilatation; p.
vestibular orifice of the aqueduct of the vestibule ;
q. osseous part of the spiral lamina, seen from the
surface which corresponds to the vestibular scala ;
r r. space which is occupied by the membraneous
part of the spiral lamina ; *. hamulus or hook in
which the bony spiral lamina ends ; t. helico-
trema; u. substance of the petrous bone, between
the first turns of the cochlea ; p. orifice of the aque-
ductus cochleae.

lining the labyrinthic cavity. —
The cavities of the osseous labyrinth which we
have just described are lined by a serous or
fibro-serous membrane, extremely delicate and
closely adherent to the surfaces. The mem-
braneous labyrinth must not be confounded with
it. This membrane, which may be compared
to that serous pellicle on the inner surface of
the sclerotica, known by the name of meni-
brana fusca or arachnoidea oculi, is more
manifest at an early age than in adults, and is
nowhere so distinct as at the places where the
nerves enter, and at the bottom of the tym-
panic scala of the cochlea. It is it which
completes the spiral septum of the cochlea, by
an arrangement immediately to be described.

The fenestra rotunda or cochlear fenestra is,
in the recent state, closed by a membrane
which shuts out the cavity of the tympanum
from any direct communication with the
cochlea. This membrane, called by Scarpa*
the secondary membrane of the tympanum,
membrana tympani st'cundaria, is concave to-
wards the cavity of the tympanum, convex
towards the tympanic scala of the cochlea, and
is received at its circumference into a groove
within the orifice of the fenestra rotunda. It
is composed theoretically of three layers, the
inner of which is nothing but the fibro-serous
membrane under consideration. The outer
layer is a continuation of that which lines the
cavity of the tympanum. The third and pro-
per layer is situated between the two men-
tioned. The same may be said in re-^ard to
that membrane, which, together with the base
of the stapes, closes the vestibular fenestra.

The membrane lining the tympanic scala
of the cochlea is continued into that lining the
vestibular scala at the opening called heli-
cotrema. The membrane of the vestibular
scala is continuous with that lining the vesti-
bule, which on its part is continuous with that
of the semicircular canals. Lastly, the same
membrane lines the aqueducts.

Such is a general description of the mem-
brane lining the labyrinthic cavity ; but to
understand the disposition of the cochlea and
aqueducts in the recent state, we must take a
nearer view of this membrane such as it exists
in those cavities, which, indeed, is the most
important and difficult part of it.

Of the cochlea in the recent state. — The
cochlea is the last addition made to the laby-
rinth in the ascending scale of the animal
series. As was said, it is in birds in a very ru-

Op. cit.

* De auditu et olfacm, cap. ii. s. 19. p. 35,

334

ORGAN OF HEARING.

dimentary state. It is in fact a mere pouch
or diverticulum not at all coiled up, in which,
however, can be distinguished a part corres-
ponding to a lamina spiralis, which is repre-
sented by a cartilage, and a vestibular and a
tympanic scala, together with a cochlear fe-
nestra. This analogy, much insisted on by
Breschet,* I gave a brief notice of some years
ago.f

The cochlea is richly supplied with nerves.
The spiral lamina is that part of it on which
its nerves expand ; this must therefore be con-
sidered as forming a very essential element of
the cochlea, and may be viewed as being in
the economy of that part of the internal ear
what the apparatus of the membraneous laby-
rinth is to the vestibule and semicircular
canals.

The bony spiral lamina is rendered a com-
plete partition between the scalae of the cochlea
by a membraneous continuation, zonula mem-
branucea lamina spiralis s. zona ValsalvSy
formed by the application against each other
of the membranes, which line the interior of
the two scalae, at the moment they are reflected
from the free edge of the bony spiral lamina
to the outer walls of the cochlea. Hence the
spiral partition of the cochlea, when complete,
is osseous at its inner or central part, and mem-
braneous at its outer or peripheral.

The outer part of the osseous zone of the
spiral lamina is thinner than the rest; it is
semi-osseous, semi -membraneous, and the
membraneous spiral lamina at its junction
with it presents a fine cartilaginous stripe ;
hence Comparetti and Sommerring described
the spiral lamina as composed of concentric
bands or zones. They admitted four, viz. 1,
the inner thick part of the bony spiral lamina ;
2, the outer thin part; 3, the cartilaginous
stripe commencing the membraneous spiral
lamina; and 4, the rest of the membraneous
spiral lamina, or the membraneous spiral la-
mina properly so called. The first zone is con-
tinued into the hamulus cochleae, the second
ceases towards the second turn of the cochlea,
and the third and fourth are continued beyond
the hamulus cochleae, forming of themselves
the spiral partition in the last turn.

It is sufficient to admit, with Breschet,J only
three zones ; an osseous zone, a middle zone,
and a membraneous zone ; the third and
fourth zones of Comparetti being compre-
hended under the latter.

The osseous zone of the spiral lamina we
have already described, and alluded to the
middle zone. The latter, when it still exists
in the dry bone, appears merely as the outer
margin of the former. It is the narrowest of
the three zones, and is most distinct in the first

* Op. cit. and also Rechcrches Anatomiques et
Physiologiques sur 1'organe de 1'audition chez les
Oiscaux. Paris, 1836.

t '• Note on the car of Birds," in the first and
only volume of the second series of the Edinburgh
Journal of Natural and Geographical Science.
Edinburgh, 1831.

J Op. cit. chap. ix. s. cxcix.

Fig. 234.

The axis of the cochlea and spiral lamina isolated,
in order to show the disposition of the three gones.
The vestibular lamina of the osseous zone is re-
moved. (From Breschet.}

A, natural size. B, magnified.
a. trunk of the cochlear nerve ; b. distribution of
the filaments of this nerve in the osseous zone ;
c. nervous anastomoses in the middle zone ; d.
membraneous zone ; e. osseous substance of the
axis ; /. helicotrema or hole of communication
betwixt the two scalae.

turn of the cochlea. Breschet describes it as
composed of the membranes lining the interior
of the two scalae, where they first meet each
other in passing from the bony spiral lamina,
together with osseous particles deposited be-
tween them. In this interstice between the
membranes also are contained the last rami-
fications of the filaments of the cochlear nerve,
still enveloped by their neurilemma, and
sprinkled over by the small bony particles just
mentioned.

Different from the middle zone, the mem-
braneous zone goes on increasing in breadth,
though not regularly, from the base to the
summit of the cochlea. It is the longest and
most extensive of the three zones. It is it
alone which extends into the last turn of the
cochlea. According to Breschet the mem-
braneous zone should be composed of three
layers, the two exterior of which should be,
as already said, formed by the membranes
lining the interior of the scalae, and the mid-
dle one by the expansion and interlacing of the
neurilemmatic sheaths from the middle zone ;
but these layers are so thin and so closely
united that they are inseparable, and constitute
a membrane of great thinness and transparency,
on which, however, bloodvessels can be easily
seen.

The membraneous zone presents a central
margin continuous with the rest of the spiral
lamina, except in the third turn of the cochlea,
where this margin forms nearly the third of
the circumference of the helicotrema, and
where it runs into the peripheral margin at an
acute angle. The peripheral margin, which
is much thicker than the rest of the mem-
braneous zone, is pervaded by a vascular sinus,
like that which in the eye runs round the
circumference of the cornea at the insertion of
the iris.

ORGAN OF HEARING.

535

Fig. 235.

. peri-
nerve.

A diagram from Breschet, intended, according to him, to give an
exact idea of the disposition of the helicotrema. The walla
of the vestibular scala are supposed to be removed.

a a a. represent the osseous and middle zone of the spiral
lamina ; its termination in the hamulus or hook is seen ;
b b b b. this darker and narrower stripe represents the mem-
braneous zone of the spiral septum ; towards the summit of
the cochlea it becomes a little broader, and at its termination
constitutes by itself alone the septum between the two scalse
at their termination ; c. the commencement of the tympanic
scala ; d. the external or great margin ; e. the internal mar-
gin of the turns of the cochlea ; the two margins d and e
meet at o; fff. the vacant space corresponding to the axis ;
it terminates at o, which corresponds to the summit of the
axis ; x. helicotrema or hole which establishes a communica-
tion between the two scalae.

The section of the peripheral margin of the
membraneous zone presents a triangular sur-
face, the base of which is inserted on the osse-
ous wall of the cochlea. This swollen margin
of the membraneous zone is, according to
Breschet, evidently continuous, at the origin
of the spiral lamina in the base of the cochlea,
with the osseous zone, a circumstance which
is particularly to be remarked in very young
fetuses, where all these parts are still cartila-
ginous. This thickened margin of the mem-
braneous zone Breschet therefore considers as
analogous to the tympanic cartilage of the
bird's cochlea, having exactly the same rela-
tions and uses.

Fig. 236.

pared to the tympanic cartilage of birds ;
/. scala vestibuli •, g. scala tympani ; h.
periosteum lining the vestibular scala,
more vascular than fibrous ; f
osteum of the tympanic scala ; j.

In vascularity and richness in
nerves, the spiral lamina bears a
great resemblance to the iris. Like
it, also, it is the partition between
two chambers, containing an aque-
ous humour, and communicating,
like the aqueous chambers of the eye,
by a single orifice.

The two scalae of the cochlea have
not the same length nor the same
diameter. Toward the base of the
cochlea the tympanic scala exceeds
somewhat the vestibular; its diameter
is, at the same time, also a little more .
considerable, as far as towards the
middle of the first turn of the spire.
The two scalse have then the same
diameter, and preserve the equality
to the commencement of the last turn.
There the tympanic scala contracts,
and in particular flattens considerably,
and is at last confounded, through the
helicotrema, with the vestibular scala,
which still continues for two-thirds of
a turn, and then ends in a cul-de-sac.
This is also to be noted in regard to
the vestibular scala of the bird's coch-
lea, which indeed is very large, and
proceeds considerably beyond the tym-
panic scala. It ends in a large cul-de-
sac called lagena.

Fig. 237.

Diagram of a transverse section of the two scales of
the cochlea (from Bresrhet).

a. a. osseous wall ; b. osseous zone compared to
the vestibular cartilage of the cochlea of birds ; e.
middle zone compared to the auditive lamellae;
d. membraneous zone ; e. cartilaginiform swelling of
the external margin of the membraneous zone, com-

i

A section of the cochlea parallel to tJie direction of
its axis, in order to show the disposition of the vohnle
of its parts. Magnified. (From Breschet.)

a. a. a. trunk of the cochlear nerve ; b. b. fila-
ments of this nerve in the osseous zone ; c. c. c. c.
nervous anastomoses in the middle zone ; d. d. d. d.
membraneous zone ; e. e. e. e. swelling of the exter-
nal margin of the membraneous zone ; 1,1, axis
of the cochlea; 2, infundibulum ; 3, 3, 3, 3, exter-
nal osseous wall of the cochlea ; 4, 4, 4, 4, osseou*
lamina separating the turns of the spire of the
cavity of the cochlea ; 5, 5, 5, 5, tympanic lamella
of the osseous zone of the spiral lamina ; 6. vesti-
bular lamella; 7, hamulus or hook, which ter-
minates the osseous zone ; 8, helicotrema, with a.
bristle introduced into it.

536

ORGAN OF HEARING.

Farther observations on the aqueducts. — The
aqueducts, the one leading from the vesti-
bule, and the other from the tympanic scala of
the cochlea, are lined by a continuation of the
thin and delicate pellicle which invests the in-
terior of those cavities.

Under the osseous scale, on the surface of
the petrous bone, where the aqueduct of the
vestibule ends, there is a small triangular pouch
produced by a separation of the dura mater into
two layers. Into this pouch the lining mem-
brane of the aqueduct enters, and ends in a
cul-de-sac. The pouch is called by Cotugno
the membraneous cavity of the aqueduct. I
found the structure just described of unusual
size, in consequence of irregular development,
in the ear of a man deaf and dumb from birth,
which I examined some years ago. The trian-
gular pouch in the dura mater was about one-
third of an inch long at its sides, and was dis-
tended by a clear liquid. Every time pressure
was made on the distended pouch, a fine jet of
liquid issued through a small opening which
had been made in the superior vertical semicir-
cular canal. Similar cases have been described
by Mondini* and others.

The lining membrane of the aqueduct of the
cochlea ends, in like manner, in a cul-de-sac,
which, however, is not so large as that of the
aqueduct of the vestibule.

The liquid contained in the labyrinthic ca-
vity, or liquid of Cotugno, or perilymph.
(Aquula Cotunnii.) — The cavities of the
osseous labyrinth contain a liquid, the secre-
tion, probably, of their thin and delicate
lining membrane. They contain no air,
us has been asserted. The liquid called the
liquid of Cotugno, or by De Blainville peri-
lymph, must not be confounded with ano-
ther which is contained in the interior of the
membraneous labyrinth. Dominico Cotugno,-)-
though not actually the discoverer of this liquid,
yet took a more correct view of it than his pre-
decessors in this branch of anatomical research,
Valsalva,t Vieussens,§ Cassebohm,|| and Mor-
gagni.H" He in fact recognised in it a substance
fulfilling some office in the exercise of hearing,
a view of the matter which was admitted by
Haller, and put beyond doubt by Ph. Fr.
Meckel,** and since their time recognised by
all physiologists.

The perilymph occupies, in the vestibule and
semicircular canals, all the space not taken up
by the membraneous labyrinth. The cochlea
contains nothing but it ; and as all the cavi-

* Comment. Bonon. torn. vii. Anatoraia Surdi
Nati. p. 422.

t De Aqueductibus Auris Humanae Anatomica
Dissertatio, s. xxix.-xxxi. Neapoli, 1760.

\ De Aure Humana Tractatus, &c., cap. iii. s. 17,
p. 79. Trajecti ad Rhennm, 1707.

$ Traitc Nouveau de la Structure de 1'oreille. p.
75. Toulouse, 1714.

|j Tractatus Quintus Anatomicus de Aure Hu-
mana, &c., pp. 20-21. De Labyrimho. Halae Magd.

^[ Kpist. Anatom. xii. s. 64. p. 469. Venetiis
1740.

** Dissortatio Anatomico-Physiologica de Laby-
rintlii Auris Contends, &c. Argentorati, 1777, s. 8.

ties of the osseous labyrinth communicate, it is
the same humour in each.

In all fishes, except the cartilaginous with fixed
gills, the labyrinthic cavity is very imperfect,
being in many of them open towards the cranial
cavity, or at the most separated from it only by
a membraneous partition, as in the cod; hence
the encephalic liquid in some of them is not dis-
tinct from the perilymph whose function it must
perform. In the cartilaginous fishes with fixed
gills, on the contrary, the labyrinthic cavity is
completely separated from the cranial ; therefore
in them we meet with perilymph distinct from
the encephalic liquid, and that, too, in pretty
large quantity.

In birds the perilymph is in much less quan-
tity than in the mammifera, in proportion to the
size of the membraneous labyrinth. In rep-
tiles the quantity of perilymph is still less.

Cotugno and Meckel supposed that the
aqueducts were a sort of diverticula, or cavi-
ties which served to let off the superabundant
perilymph, when necessary, during the act of
hearing. This opinion is, however, novv-a-days
very much questioned, and several anatomists,
Brugnone, Ribes, Breschet, &c., refuse to those
aqueducts the uses which Cotugno assigned
them, and consider them merely as canals des-
tined for the passage of bloodvessels. Although
they may be insignificant in a physiological
point of view, still, if the description I have
given of them be correct, they must be consi-
dered as something more than mere canals for
the transmission of vessels. The constancy of
the aqueducts, moreover, is another argument
against their being mere vascular canals.

Breschet,* and in Hildebrandt's Anatomic by
Weberf the same idea is concisely expressed,
explains the mode of formation of the aque-
ducts by supposing that at first the labyrinthic
cavity is nothing but a sac formed by a prolon-
gation of the dura mater in the same way as the
tunica vaginalis is of the peritoneum ; that as
development proceeds, the tube of communi-
cation between the labyrinthic sac of the dura
mater and general cavity of the dura mater is
gradually contracted and elongated ; and that as
ossification extends, the tube becomes sur-
rounded by osseous substance, and presents
itself under the appearance of an aqueduct.

"This view," says Breschet, "is rendered
probable, for in many fishes the labyrinthic
cavity forms one with that of the cranium,
and if, in these animals, a prolongation of the
walls of the cranium tended to separate the
brain from the ear, there would result a small
canal establishing a communication between
the two cavities, and this canal would be
nothing but an aqueduct."

According to this view, the lining membrane
of the labyrinthic cavity may be considered as
a continuation of the arachnoideal layer of the
dura mater, perhaps of the dura mater also.

2. The membraneous labyrinth, ( labyrinthus
membranaceus. Fr. Labi/rinthe metnbraiicuv.
Germ. Das hautige Labyrinth.) — Within the

* Op. rit.

t .Band iv. p. 32.

ORGAN OF HEARING.

537

osseous labyrinth is contained an extremely
delicate and complicated membrane - ner-
vous apparatus, called, membraneous laby-
rinth, first properly described by Scarpa.*
It does not extend into all the compartments
of the osseous labyrinth, but only occupies the
vestibule and semicircular canals. The coch-
lea, as has been said, contains in its cavity
nothing but perilymph.

The vestibular part of the membraneous
labyrinth, and of that perhaps one of the
pouches only, is all that is really fundamental
in the structure of an organ of hearing. In
the Crustacea and Cephalopodous Mollusca in
which the organ of hearing exists in its sim-
plest form, and even in the Cyclostomatous
fishes there is nothing but a small pouch con-
taining a little liquid and a lapilliform body.

Much smaller than the cavities which con-
tain it, the membraneous labyrinth is sus-
pended as it were in the perilymph. It does
not appear to adhere to the walls of the laby-
rinthic cavity except at the points where it re-
ceives nervous filaments.

The component parts of the membraneous
labyrinth are: —

1. The common sinus. 2. The membrane-
ous ampullae and semicircular tubes. 3. The
saccule.

Fig. 238.

A magnified representation of the left osseous laby-
rinth laid open to show the membraneous labyrinth
in its situation. (From Breschet,)

a. membraneous ampulla of the ampullary sinus
of the anterior semicircular canal ; b. membrane-
ous ampulla of the ampullary sinus of the external
semicircular canal ; c. membraneous ampulla of
the ampullary sinus of the posterior semicircular
canal; d. anterior membraneous semicircular tube;
e. external membraneous semicircular tube ; f.
posterior membraneous semicircular tube ; g. com-

* De auditu et olfactu.

mon membraneous tube resulting from the junction
of the tubes d and f; h. the place where the ex-
ternal membraneous semicircular tube opens into
the common sinus ; i t. common sinus filling a
great part of the vestibule ; k. a small mass of
calcareous powder shining through its walls ; / /.
saccule, also containing, m. another mass of cal-
careous powder ; n a nervous fasciculus, furnishing,
o. an expansion to the anterior membraneous am-
pulla ; p. another to the ampulla of the external
tube, and q. a third to the common sinus ; r. ner-
vous fasciculus to the saccule ; another fasciculus
of nervous filaments, not lettered, is seen going to
the ampulla of the posterior membraneous semi-
circular tube ; s s. spiral lamina ; «'. the termin-
ation of the spiral lamina in the hamulus ; /. com-
mencement of the scala tympani near the fenestra
rotunda, which is here no longer seen ; «. com-
mencement of the scala vestibuli ; x. extremity of
the axis around which the termination of the spiral
lamina turns ; y y. a bristle engaged in the heli-
cotrema ; z. place where the summit of the axis
is continued into the wall of the osseous labyrinth ;
www, membraneous portion of the spiral lamina,
particularly broad in the last turn, (lettered « « u
in the figure instead of w w w~) ; ****** spaces
between the walls of the labyrinthic cavity and
membraneous labyrinth occupied by the peri-
lymph.

Fig. 239.

The left membraneous labyrinth isolated together with
the nerves. Magnified. ( From Breschet.)

a. ampulla of the anterior semicircular tube ;

b. ampulla of the horizontal semicircular tube ;

c. ampulla of the posterior semicircular tube ; d.
common tube ; e. mass of calcareous particles
lying in the common sinus ; /. the saccule con-
taining also a mass of calcareous particles; k.
portio dura of the seventh pair ; m. nervous fila-
ments to the ampulla of the anterior semicircular
tube ; n. filaments to the ampulla of the hori-
zontal semicircular tube; filaments are also seen
going to the ampulla of the posterior semicircular
tube, not lettered ; o. filaments to the common
sinus ; q. filaments to the saccule ; r. cochlear
nerve.

The common sinus, membraneous ampulla,
and membraneous semicircular tubes. — - These
constitute but one apparatus which is just the
counterpart of the vestibule, ampullary sinuses,
and semicircular canals of the osseous laby-
rinth ; the semicircular tubes opening into the
ampullae and common sinus in the same way

538

ORGAN OF HEARING.

that the semicircular canals open into the am-
pullary dilatations and the vestibule.

The common sinus is an elongated, laterally
compressed pouch, and lies in the posterior
part of the vestibule. It extends into the
upper horn to join the ampullae of the superior
vertical, and tof the horizontal semicircular
tubes ; and into the posterior and lower horn,
to join the ampulla of the posterior semicircular
tube, and to receive the tubulus communis
and cylindrical extremity of the horizontal
tube, as they emerge from their respective
canals. Its upper end, which is larger than
its lower, lies in the hemi-elliptical cavity, to
the bottom of which it is fixed by nervous
filaments.

The membraneous tubes are only about a
third part of the calibre of the semicircular
canals in which they are contained. Like the
latter they are distinguished by the epithets,
superior vertical, posterior vertical, and hori-
zontal. Each membraneous semicircular tube
opens at one of its extremities, like its cor-
responding osseous canal, into an oval dila-
tation called ampulla, which on its part com-
municates with the common sinus. As the
vertical semicircular canals unite at one of
their exiremities to form the common canal,
so their corresponding membraneous tubes
also unite to form a common tube, tubulus
communis, which occupies the common canal.

At the place where the nervous filaments
enter the common sinus, its wall presents a
much more considerable thickness and consist-
ence than elsewhere.

According to Steifensand,'* who has ex-
amined the structure of the ampullae very
carefully, each ampulla presents a very much
arched surface, superficies convexa, and op-
posite to this a concave or indented surface,
superficies concava s. inftexa, which receives
the nervous filaments. Where the nerve enters
there is a transverse depression, sulcus trans-
versus, by which this surface is divided into
two parts. This transverse depression on the
outside produces in the interior a fold of the
membrane composing the wall of the ampulla,
and through which the nerve enters. This
fold forms a transverse septum, septum trans-
versum, which divides the interior of the am-
pulla into two parts ; one of which, the sinus
part, communicates by the osteum sinus with
the common sinus, and the other, the tube part,
by the osteum tubuli with the membraneous
tube.

Saccule, sacculus rotundas. This is a round
membraneous bag, smaller than the common
sinus in front of which it lies in the hemisphe-
rical depression of the vestibule. It is firmly
fixed in its place by nervous filaments which
proceed to it through the apertures observed
in the bottom of the hemispherical depression.
As has been mentioned in regard to the com-
mon sinus, the wall of the saccule presents an
increase of thickness and consistence at the
place where the nervous filaments enter it.

* Muller's Archiv. fur Anat. Physiol. und wis-
senschaftl. Medecin. 1835. Heft. II. pp. 173, 174.

Small in the Mammifera, the saccule is very
distinct and large in fishes.

The common sinus and saccule adhere to
each other, but whether their cavities com-
municate has not been determined. They are
fixed, as has been said, to the inner wall of the
vestibule, by the nervous filaments which they
receive through the apertures with which that
part is perforated. Towards the outer wall
they are nowhere in contact with the base of
the stapes, the perilymph intervening. This
circumstance, first distinctly pointed out by
Scarpa,* and particularly insisted on by Bre-
schet, shows that it is only by the intermedium
of the perilymph that the movements of the
stapes can have any impression on the nervous
expansions of the membraneous labyrinth.

The common sinus, ampullae, semicircular
tubes, and saccule are composed of a firm trans-
parent membraneous coat,within which is a ner-
vous expansion, and outside which is a cellulo-
vascular layer, in some places tinged black or
brown. Of the nervous expansion we shall
speak under the head of the auditory nerves.
In the sheep, hare, rabbit, &c. the walls of
the membraneous labyrinth present patches of
black pigment, a circumstance noticed by
Scarpa,f Comparetti,} and Breschet.§ Before
I knew of the observations of these anatomists
I had myself observed the fact. I was not,
however, led to the discovery of it by accident ;
but, being engaged in researches on the pig-
ment of the eye, and considering the analogy
which the organs of sense bear to each other
in their general anatomical structure, I was
curious to know whether pigment did not exist
also in the ear. Examination proved to me
that it did ; for I found, as Scarpa and Com-
paretti had previously noticed, pigment de-
posited in the form of small black spots in the
membraneous parts of the labyrinth in dif-
ferent Mammifera. In some I have found a
distinct cellulo-vascular layer of a black or
brown colour forming the outer surface of the
membraneous labyrinth. And, contrary to
what Breschet asserts, I have found pigment
in the membraneous labyrinth of the human
ear also. It appears, especially on the am-
pullae, under the form of a slight but perfectly
distinct brown tinge, similar to what is seen
around the ciliary processes in the eyes of
Albinos.

Semicircular tubes are found in all the Ver-
tebrate animals, with the single exception of
the Cyclostomata. When they do exist there
are never more nor less than three.

The common sinus, ampullae, semicircular
tubes, and saccule contain a limpid humour.
Suspended in this humour there is found in
the common sinus and also in the saccule a
small mass of calcareous powder.

The liquid of' the membraneous labyrinth,

* Anatomicae disquisitiones de Auditu et Olfactu,
s. xvi. p. 55.

t Op. cit. s. iv. p. 49.

t Observat. Anatom. dc aure interna comparat.
p. xxxii. Praefat.

§ Op. cit.

ORGAN OF HEARING.

539

or endolymph or vitreous humour of the ear.
(Auuula labyrinth* mernbranacei. Humor
vitreus auris. Fr. Vitrine auditive. Germ.
]{</»</• c/es hdutigen Labyrinths. Die
GlasJ'euchtigkeit des Ohres. — This humour,
first distinctly pointed out by Scarpa, fills
exactly all the cavities of the membrane-
ous labyrinth, — that is to say, in the human
ear, the common sinus, ampullae, the semi-
circular tubes, and saccule. Like the peri-
lymph, it is almost as limpid as water. In
the endolymph there are, as has been said,
always found suspended calcareous concre-
tions. The endolymph is ,jn birds as limpid
as in the Mammifera; but in reptiles it is in
general more dense than water and a little
viscid. It is viscid in all fishes, but especially
so in the Chondropterygenous, in which it often
presents itself in the form of jelly. It is also
very decidedly viscid in the Cephalopodous
Mollusca.

The masses of calcareous matter contained
within the membraneous labyrinth. — In the ear-
bulb of all animals which possess one, there
are found small masses of a chalky nature ;
in some solid, in others pulverulent. Solid
concretions are found in the osseous fishes,
and in the Chondropterygenous fishes with free
gills, such as the sturgeon. The chalky mat-
ter is in a pulverulent state in Mammifera,
birds, reptiles, and in Chondropterygenous
fishes with fixed gills. In the Batraclnan rep-
tiles and Cephalopodous Mollusca, the cal-
careous matter appears rather under a concrete
form.

These calcareous masses are best known in
osseous fishes, in which they are hard but
brittle bodies of a determinate shape. In
those animals, indeed, they have been erro-
neously considered as analogous to the tym-
panic ossicles of the higher Vertebrata. MM.
Breschet* and Iluschkef have lately called
particular attention to the subject, and have
described masses of calcareous matter in the
ear of reptiles, birds, and Mammifera. Scarpa
and Comparetti had observed them in the
human ear, without, however, detecting their
nature. But they had been unequivocally
noticed before by De Blainville ; J and pre-
viously to the first publication of Breschet's
papers on the ear in the Annales des Sciences
Naturelles, I had also studied them throughout
the animal series.

Breschet has proposed for the solid masses
the name of otolithi, from ov$, auris, and ?u6o$,
lapis; and for the pulverulent ones that of
otoconia, from oi>$, and x<w?» pulvis. Otoconia
has been translated into German by Lincke §
Ohrsand. Huschke calls the pulverulent matter

* Lib. cit.

t Isis, 1834. Heft. 1. p. 107. 1833. Heft. vii.
p. 676.

£ De 1'Organization des Animauxou Principes
d' Anatomic comparee, torn. i. p. 451-458. Paris,
1822. Also, Cours «le Physiologic generale et com-
paree, &c. Paris, 1829. xii Le9on. p. 399.

$ Das Gehb'rorgan, &c. s. 176. p. 203. Leipzig.

ear-crystals, Ohrkrystalle. Krause, ear-chalk,
Ohrkalk.

In the ear of man and the Mammifera in
general there are two masses of calcareous
matter; one in the common sinus and the
other in the saccule. According to Huschke
and Barruel they are composed of mucus,
carbonate and phosphate of lime, and some
animal matter. They are said to be more dis-
tinct in the fcetus than in the adult. From my
own observations I should say that they exist
in the human adult as distinctly as in the foetus.
Concretions are never found in the ampullae or
semicircular canals, either in man or any of
the lower animals.

Examined in man and the Mammifera the
concretions are suspended in the endolymph,
and correspond to the points of the common
sinus and saccule where the nervous filaments
are implanted.

The grains composing the calcareous mass
are held together by a soft mucous tissue.

Huschke describes the grains as crystalline,
small six-sided columns, pointed at the ends
with three surfaces. They appear to me, under
the microscope, to have an oval form, more or
less elongated, in man and the mammifera,
passing into a spindle shape in birds and rep-
tiles, and, though transparent, they do not pre-
sent any very decided crystalline form. The
particles of chalk examined through the micro-
scope have a somewhat similar appearance, but
much smaller. The grains of the ear are of
different sizes. Of a mass which I removed
from the ear of a middle-aged man, the greatest
number had their longest diameter equal to that
of the globules of the human blood, that is,
. about the three-thousandth part of an inch.

There is found in the cochlea of birds a mass
of calcareous matter. Breschet says he has
found, in cochleae of the human fcetus, which
had been dried but not macerated, small masses
of cretaceous matter deposited near the summit
of the cochlea ; and Huschke* once found, in
the fluid of the cochlea of a child, a collection
of microscopical crystals.

Cruveilhier* asks, do the small masses of
cretaceous matter, found in the ear of man and
the mammifera, fulfil the same function as the
stones in the ear of fishes ? or must they be
considered as a remains only of a part import-
ant in other animals ? Breschet says, *' the
otolithes and otoconies have, for their use, to
communicate to the nervous extremities a more
vivid and energetic impression than a simple
liquid like the endolymph could do; for the
vibrations of a solid body are much more sen-
sible for their force and degree of intensity than
those of a liquid body." However this may be,
it appears that the development of these con-
cretions coincides, in some degree, with the
medium inhabited by the animal ; thus, they
are stony in most animals living in water, and
pulverulent in such as exist in air.

The auditory or acoustic nerve. — Nervus au-

* Loc. cit.

t Anatoinie descriptive, tome iii. p. 524.

540

ORGAN OF HEARING.

ditorlus s. acusticus. — Fr. Nerfauditifou acous-
tique. — Germ. Der Gehornerv. — The internal
auditory meatus of the temporal bone appears
to end in a cul-de-sac ; but, examined more
closely, the bottom is found divided into two
unequal-sized depressions, an upper and a
lower, by a crest, which extends backwards
from the anterior and outer wall of the meatus.
The upper depression, which is the smaller, is
subdivided into two, an anterior and a posterior,
by a small vertical pillar. The anterior leads
into the aqueduct of Fallopius, and gives pas-
sage to the facial nerve. The posterior is almost
funnel-shaped, and presents two or three pretty
large apertures, and several smaller and less
distinct ones. These are the mouths of small
canals which lead into the vestibule, and their
terminating orifices produce that sieve-like ap-
pearance in the pyramidal elevation between
the hemi-elliptical and hemispherical depres-
sions, and which extends towards the ampullary
dilatations in the superior horn of the vestibule.
The lower and larger depression presents two
subdivisions. The anterior and larger corres-
ponds to the base of the axis of the cochlea ;
it presents a spiral groove or tract — tract us spi-
raiisjoraminulentus, answering to the turns of
the cochlea, and perforated like a sieve by nu-
merous apertures, which diminish in size towards
the centre, where there is one opening larger
than the rest. The posterior subdivision of the
lower depression is a small superficial fossa,
perforated by two or three larger, and a great
number of smaller apertures, which open into
the hemispherical depression of the vestibule,
producing the sieve-like spot already mentioned
as existing there. Below this superficial fossa
there is a pretty large hole, leading into a
canal in the posterior wall of the vestibule,
which opens by several small orifices, forming
the sieve-like spot within the mouth of the
ampullary dilatation of the lower extremity of
the posterior vertical semicircular canal.

The different minute apertures we have de-
scribed give passage to the fibrils of the audi-
tory nerve.

The internal auditory meatus is lined by
dura mater.

The facial nerve enters the internal auditory
meatus along with the auditory nerve. At the
bottom of the meatus there is a communication
between the two nerves, which was first pointed
out by Mr. Swan. Separating from the audi-
tory nerve, the facial leaves the internal meatus,
by entering the aqueduct of Fallopius.

From its origin to about where it enters the
internal auditory meatus, the auditory nerve
presents most distinctly the delicate-walled
tubular structure of brain. Within the mea-
tus it assumes the ordinary thick-walled cylin-
drical tubular structure of nerves ; a circum-
stance overlooked by Ehrenberg, when he ad-
duced, as a peculiarity of the special nerves of
sense, that they presented throughout their
course the so-called varicose tubular structure.

The auditory nerve divides into two branches
— an anterior, or cochlear ; and a posterior, or
vestibular branch, — which externally remain

united together as far as the bottom of the
meatus. The former is whiter, and has its fila-
ments more compactly bound together than the
latter. Examined under the microscope, the
cylindrical tubules of the cochlear nerve ap-
peared to me to be larger than those of the
vestibular, and to contain, or at least to give out,
a greater quantity of nervous medulla.

The anterior branch, or cochlear nerve, ner-
vus cochlea, is something like a flat tape rolled
on itself longways. It proceeds forwards to
that depression at the bottom of the internal
auditory meatus, already described as corres-
ponding to the base of the axis. Here it resolves
itself into a number of fine filaments, which
enter the apertures in the spiral tract of holes.
Traversing the small bony canals leading from
those apertures into the substance of the axis,
they enter the bony spiral lamina according as
their turn comes, by bending nearly at a right
angle, and spread out upon it. The first fila-
ments given off are the largest, the rest gradually
diminish in size.

The first turn of the spiral lamina is supplied
by those which enter the first turn of the spiral
tract of holes ; the second turn receives the
filaments which traverse the bony canals, into
which the fine apertures of the second turn of
the spiral tract lead ; and the last half turn is
supplied by that large bundle of filaments ter-
minating the nerve, and which, entering the
axis by the large opening in the centre of the
spiral tract, emerges at its summit.

The vestibular nerve, nervus vestibuli, which
presents a small gangliform enlargement, di-
vides into three branches. The uppermost,
which is the largest, lies in the depression be-
hind the entrance to the aqueduct of Fallopius.
Its filaments having penetrated the vestibule
by the small apertures of the canals already
mentioned in the pyramidal elevation, arrange
themselves into three fasciculi; of which one is
distributed to the common sinus, and the other
two to the ampullae belonging to the superior
vertical and to the horizontal semicircular tube.
The fibrils of the next branch enter the ves-
tibule by the apertures at the bottom of the
hemispherical depression, and terminate in the
saccule.

The third, or lowest branch, which is the
smallest, enters that canal described in the pos-
terior wall of the vestibule, and which opens
by a sieve-like spot within the ampullary dila-
tation of the posterior semicircular canal. Its
fibrils are distributed to the ampulla of the
posterior semicircular tube.

Such is the description of the divisions of
the auditory nerve as given by most authors,
and as it has appeared to me in the examina-
tions I have made. Krause and Breschet, how-
ever, describe the mode of division differently.
The former says the nerve of the saccule comes
off from the cochlear nerve ; the latter, that the
cochlear nerve (which he calls the posterior
fasciculus of the auditory nerve) gives off both
the saccular nerve and the filaments to the pos-
terior ampulla. I have not at present an oppor-
tunity to repeat my examination of the parts,

ORGAN OF HEARING.

Ml

to enable me to say positively which description
is the most correct.*

The nervous fibrils of the cochlea, according
to Breschet, traverse the osseous zone of the
spiral lamina under the form of cylindrical
bundles, which, in the middle zone, become
flat, and anastomose by loops. These loops
are intermingled with small osseous particles.
Near the outer margin of the middle zone, the
neurilemma leaves the nervous filaments, and
goes to form the framework of the membraneous
zone, whilst small globules are seen irregularly
disseminated around the convexity of the loops
which the filaments form by their anastomoses.
All this, however, is not so unequivocally dis-
tinct as Breschet pretends. What I have been
able to see in regard to the termination of the
nerves on the spiral lamina, is simply this : —
The tubular structure of the nervous filaments
ceases, among grains of nervous matter ar-
ranged into a sort of expansion. There is
nothing that can be called a termination in
loops. Mueller thinks the nervous fibrils do
not form loops in the bird's cochlea. " But,"
says Mueller, " it is of no consequence, in the
present state of the physiology of the nerves,
whether the nerves of sensation form at their
terminations loops or not."

Treviranusf found a papillary termination
of the nervous filaments, not only in the retina,
but also in the nervous expansions of the ear
and nose. The papillae of the auditory nerve
he saw on the spiral lamina of the cochlea in
young mice. The osseous part is entirely
covered with filamentous papillae, lying close
together. Gottsche also found the ends of the
nerves of the cochlea in hares and rabbits club-
shaped. In the hare, the nervous cylinders ter-
minate in an oval knob.

The following figures from Breschet illustrate
his views of the mode of termination of the
nervous filaments of the cochlea.

JVg. 241.

The cochlear nerve entirely isolated. (Magnified.)
a, a, a. trunk of the nerve ; b, b, b. its filaments
in the osseous zone of the spiral lamina ; c, c, c. the
anastomoses in the middle zone.

* In the sheep I have found the division of the
auditory nerve corresponding to the first description
given above.

t Beitrage, &c. Isten Bandes 2tes Heft. Neue
Untersuchungen ueber die organischen Elemente
der thierischen Koerper, p. 55. Bremen, 1835.

A, a tmall piece of the spiral lamina, natural size,
as seen from the surface corresponding to the scala
vestibuli.

B, the same part considerably magnified to show
the globular structure (?) of the nerves and the mode
in which the neurilemma leaves them at the place
where they form their anastomoses.

a. Portion of the trunk of the cochlear nerve ;

b. fasciculi lodged in the osseous zone of the cochlea ;

c, c. anastomoses in the middle zone ; d, d, d. the
neurilemma leaving the nervous loops, interlacing
and forming the basis of the membraneous zone.

As to the mode in which the nervous fila-
ments enter and terminate in the membraneous
labyrinth. The nervous filaments, according
to Scarpa, before penetrating the vestibule of
the small bony canals, lay aside their thicker
sheath, and become softer and whiter. The
filaments expand on the parts for which they
are destined, appear to form a network, and,
having penetrated into the interior, are resolved
into a nervous pulp which lines the inner sur-
face. Scarpa compares this nervous expansion
in the saccule to the retina.

According to Breschet's account, the nervous
filaments, in penetrating into the interior of the
different membraneous pouches, are accompa-
nied by a sheath furnished by the pouch itself,
which is folded inwards, and accompanies them
until these filaments spread themselves out.
Hence it is that, at the entrance of the nerves,
the walls of the pouch are always thicker, and
form a more or less considerable projection in
the interior. This prominence is slight in the
saccule and common sinus, but very well
marked in the interior of the ampullae, where it
forms a sort of incomplete septum across ; a
structure which is small in man and the mam-
mifera, but very much developed in birds and
the higher reptiles.

At those prominences the nervous filaments,
says Breschet, present anastomosing loops, and
the neurilemma leaving them to be incorporated
with vessels, and thus to form the framework
of the membraneous labyrinth, the nervous
globules come into immediate contact with the
mass of calcareous matter.

What I have said of Breschet's account of

542

ORGAN OF HEARING.

the terminations of the cochlear nerve is also
applicable here. The filaments of the nerves
of the common sinus and saccule expand in a
fan-like manner on their walls, and having pe-
netrated them, are resolved into a nervous layer
like the retina, situated on the inner surface of
the walls of those cavities. This nervous layer
is, in the human ear, pervaded by extremely
minute transparent fibres. In the rabbit I have
distinctly seen, with a doublet magnifying 150
diameters, a fibrous or tubular structure similar
to that of the retina first discovered by Ehren-
berg.

As regards the entrance of the nerves of the
ampullae, Steifensand* gives a similar but more
detailed account than Breschet. He says, the
nerve, after having embraced in a forked man-
ner about a third of the circumference of the
ampulla, enters the wall of it.

Resolving itself now into infinitely fine fila-
ments, the nerve penetrates the septum which
lies quite close to the opening in the common
sinus, and which resembles a semi lunar emi-
nence projecting into the interior. It now
covers the surface of the septum and a circum-
scribed portion of the adjacent inner surface of
the wall of the ampulla with an extremely deli-
cate nervous pulp. The two ends of the semi-
lunar septum, gradually flattening and spread-

Fig. 242.

Common sinus, together with the ampullae and semi-
circular tubes, and the entrance of the nerves into
them. (From Steifensand.)

Fig. 243.

The ampullae of the superior and horisontal semi-
circular tubes, with a part of the common sinus. The
fan-like expansion of the nervous fibrils on the latter
is seen, and also the fork-like expansion of the nerves
on the outer surface of the ampulles. Magnified.
(From Steifensand.)

* MuUer's Archiv. fur Anatomie, Physiologic,
und wissenschaftliche Medecin, 1835. Heft. ii.
s. 174 and 184.

ing out, lose themselves in the wall of the am-
pulla.

Fig. 244. Fig. 246.

Fig. 245.

Fig. 244, (from Steifensand.) The ampulla
opened in order to exhibit the septum.

Fig. 245, (from Steifensand.) The fork-like ter-
mination of the nerve of the ampulla and the semilunar
septum, having the appearance of pure nervous sub-
stance.

Fig. 246, (also from Steifensand.} The expan-
sion of the nervous pulp over the septum.

Bloodvessels of the labyrinth. — The prin-
cipal artery of the labyrinth is the arteria
auditiva interior. It is a branch of the basi-
lar. It enters the internal auditory meatus
along with the nerve of the seventh pair, and
at the bottom of it divides into two branches,
the cochlear and vestibular arteries, which
enter the labyrinth with the corresponding
nervous filaments.

The cochlear artery, arteria cochlea, divides
into a number of branches which enter the
cochlea by the spiral tract of holes ; one in par-
ticular, arteria centralis modioli, passes through
the central canal of the axis as far as the apex
of the cochlea.

The vessels of the walls of the cochlea are
more numerous in the scala vestibuli than in
the scala tympani. The arterial branches on
the spiral lamina anastomose with each other
at the outer margin of the osseous zone. From
the convexity of the anastomotic arches nume-
rous small arteries arise and run parallel as far
as the outer margin of the middle zone, where
they again anastomose, forming loops infinitely
smaller, from the convexity of which capillary
vessels run. These capillary vessels terminate
in a sinus of a venous nature, lodged in the
substance of the outer margin of the spiral
lamina.

The vestibular artery, arteria vestibuli, sup-
plies the vestibule and semicircular canals to-
gether with their contents, the saccule, common
sinus, ampullae, and semicircular tubes, and
sends a branch along the surface of the spiral
lamina corresponding to the vestibular scala.
The stylo-mastoid artery, a branch of the poste-
rior auricular, sends a twig to the external
semicircular canal. The occipital artery also
frequently sends twigs to the labyrinth.

The bloodvessels form a beautiful plexus on
the ampulla?, and considerable trunks run along
the whole length of the semicircular tubes, sup-
ported on their surface by a delicate cellular
tissue, which forms the vehicle for the passage
of the small lateral branches given off to the
walls of the tubes.

ORGAN OF HEARING.

543

Not much is known of the veins of the laby-
rinth. The internal auditory artery is accom-
panied by a corresponding vein which carries
away the blood from the labyrinth, and empties
it into the superior petrosal sinus. Another
vein, says Weber,* goes perhaps from the laby-
rinth through a small opening in the cleft of
the aqueduct, and empties itself into the trans-
verse sinus.

Of the veins of the cochlea, some, according
to Breschet, accompany their arteries ; others
enter the sinus, lodged in the substance of the
outer margin of the spiral lamina. Near the
base of the cochlea, this sinus communicates
with the veins of the vestibule.

Nothing is known of the absorbents of the
labyrinth.

Fig. 247.

A section of the cochlea parallel to its axis, showing
the distribution of the vessels in its interior. It is the
veins that are delineated, but their distribution is
almost the same as that of the arteries. Magnified.
(From Breschet.)

a, a. Veins accompanying the trunk of the coch-
lear nerve, and penetrating the nervous branches
across the spiral lamina ; b. first anastomoses at the
periphery of the osseous zone ; c, c. second anasto-
moses at the periphery of the middle zone ; d. last
ramuscules, which are almost parallel, occupying
the membraneous zone ; e, e, e. venous sinus in
the peripheral margin of the membraneous zone.

II. ACCESSORY PARTS OF THE APPARATUS

OF HEARING.

Of these parts, the auricle collects the so-
norous undulations, and the auditory passage
conducts them to the middle ear or tympanum,
where they are modified and transmitted to the
sensitive part of the apparatus, the ear-bulb.

A tympanum is found in reptiles, birds, and
Mammifera, a perfect external ear only in the
Mammifera. The lip-like folds of skin before
the membrana tympani, in some birds and rep-
tiles, may, however, be considered rudiments
of an external ear. Among the Mammifera,
the Cetacea have no auricle, and only a very
contracted auditory passage.

It was said that the tympanum exists in a
greater number of animals than the cochlea.
This refers to a discovery made by Weber ,f
that a prolongation of the swimming-blad-

* In Hildebrandt's Anatomic.
t De Aure et auditu Hominis et animalium,
Lipsis, 1820.

der in the herring, in the cyprinoid fishes,
in silurus glanis, and in several species of
cobitis, has a connexion with the membraneous
labyrinth in the same manner that the prolon-
gation of the mucous membrane of the throat,
forming essentially the tympanum and Eusta-
chian tube, is extended to the surface of the
labyrinth; and moreover, that in all those
fishes, with the exception of the herring, there
exist bones analogous to the tympanic ossicles
in the higher animals.

1. The middle ear, or tympanum, and its ap-
pendages.

The cavity of the typanum, cavitas tympani;
Fr. came du tympan ou du tambour; Germ, die
Trommelhohle oder Paukenlwhle. — The cavity
of the tympanum is a space lying at the peri-
pheral surface of the ear-bulb, and measuring
from above downwards as well as from before
backwards about four-tenths of an inch, and
from without inwards about three-twentieths of
an inch. It is bounded internally by the outer
wall of the osseous labyrinth ; externally by a
vibratile membrane, the membrana tympani,
and that portion of the temporal bone into
, which it is framed. Anteriorly a canal, the
a' Eustachian tube, leads from it into the throat ;
| and posteriorly and superiorly it communicates
with the mastoid cells.

The cavity of the tympanum is traversed by
a chain of small bones, extending from the
membrana tympani to the vestibular fenestra,
and is lined by a very delicate membrane of a
fibro-mucous character, which is prolonged into
all its sinuosities and dependent cavities. This
membrane is moreover reflected on the parts
which traverse the cavity, and envelopes them.
The lining membrane of the tympanum is con-
tinuous through the medium of that of the
Eustachian tube, with the mucous membrane
of the throat.

A condition essential to the due performance
of the function of the tympanum is that the
external air have free access to its cavity.

Examined on the dry bone, the inner wall
of the tympanum presents a considerable emi-
nence ; behind and below which is an opening
somewhat of a triangular form, and in a fossa
above it another opening, about twice the size
of the preceding, and of an ovoid shape. From
the description which has been already given
of the osseous labyrinth, it will be immediately
perceived that the eminence in question, called
the promontory, is that which the commence-
ment of the cochlea forms ; that the opening
below and behind it is the fenestra rotunda or
cochlear fenestra, and the opening above it the
Jenestra ovalis or vestibular fenestra.

The surface of the promontory is marked by
a groove ; sometimes instead of a groove there
is a canal. This groove is continuous below
with a canal, several lines in length, which
opens in that depression in the partition be-
twixt the lower orifice of the carotid canal and
the foramen lacerum posterius. Above, in front
of the vestibular fenestra, the groove again runs
into a canal which proceeds forwards and up-
wards between the canal for the internal muscle
of the malleus and the commencement of the

544

ORGAN OF HEARING.

aqueduct of Fallopius, and opens on the upper
surface of the petrous portion of the temporal
bone outside and in front of the hiatus of Fal-
lopius. This canal, first accurately described
by Arnold,* and called by him the tympanic
canal, canalis tyrnpanicus, is traversed by the
nerve of Jacobson, which establishes a com-
munication betwixt the glosso-pharyngeal and
the otic ganglion. Besides this groove there
are several others corresponding to the branches
of the tympanic plexus of nerves.

The opening below and behind the promon-
tory, the fenestra rotunda or cochlearj'enestra,
leads, by a short infundibuliform canal directed
obliquely inwards, into the lower or tympanic
scala of the cochlea. Looking into this very
short canal sideways, a groove is remarked en-
circling the margin of its inner orifice. This
groove receives the circumference of the secon-
dary membrane of the tympanum.

The opening above the promontory, the fe-
nestra ovalis or vestibular j'enestra, has already
been described in speaking of the vestibule.
All that we have to add here is that it is sur-
rounded externally close to its edge by a small
channel or groove.

Above the vestibular fenestra and running in
much the same direction as its long diameter
is a round elongated ridge, within which is the
aqueduct of Fallopius. Below this ridge and
behind the vestibular fenestra is a small mam-
millary or pyramidal eminence, called the pyra-
mid, eminent ia papillaris s. protuberantia py-
ramidalis. The apex of the pyramid, directed
forwards and a little outwards, presents an
opening leading into a canal, which extends
backwards and downwards, then becoming
vertical lies in front of the lower part of the
aqueduct of Fallopius. In the thin lamina of
bone which separates the two canals there is
an aperture. The muscle of the stapes is
lodged in the canal, and its tendon issues by
the aperture in the apex, of the pyramid.
About one-sixth of an inch behind the pyra-
mid and close to the groove for the insertion of
the circumference of the membrana tympani
is the opening by which the chorda tympani,
accompanied by an artery, enters the tym-
panum.

In front and a little above the vestibular
fenestra, and on the anterior extremity of the
prominence of the aqueduct of Fallopius, is a
tubular projection with a wide open mouth
directed outwards. This tubular projection,
which is generally found incomplete in the
dry bone, in consequence of being composed
of a very thin brittle substance, is what has
been called the cochleariform process. It is
the continuation, bent at nearly a right angle
outwards, of the canal or half canal, about half
an inch in length, and destined for the recep-
tion of the internal muscle of the malleus,
which lies above the osseous part of the Eusta-
chian tube, and is separated from it merely by

* Ueber den Canalis tympanicus und mastoideus,
in Tiedemann's, Treviranus, und Gmelin's Zeit-
schrift fur die Physiologic, B. iv. Heft 2, No. xxi.
p. 284.

a thin lamina of bone, the continuation
that forming the tubular projection.

Fig. 248.

The inner wall of the tympanum.

a. Promontory ; b. vestibular fenestra ; c. coch-
lear fenestra ; d. pyramid ; e. eminence of the
aqueduct of Fallopius ; /. cochleariform process
and half canal for the internal muscle of the mal-
leus.

The outer wall of the tympanum is formed
by the membrana tympani and the inner ex-
tremity of the osseous part of the external au-
ditory passage, in which the membrana tympani
is framed.

Osseous portion of the auditory passage. —
This leads from the outside of the temporal
bone. In front of it lies the glenoid cavity,
and behind it is the mastoid process. It is
about three-quarters of an inch long. Its
course is from without inwards and from
behind forwards, at first a little upwards and
then downwards. It is wider at either extre-
mity than in its middle. A cross section of
the passage presents an elliptical orifice, the
long diameter of which is directed from behind
forwards and from below upwards. Its extre-
mities are cut obliquely in such a way that in-
ternally the anterior wall exceeds the posterior,
whereas at the outer orifice the posterior wall
exceeds the anterior in length.

The margin of the outer orifice is rough and
irregular to give attachment to the cartilaginous
portion of the passage and to the auricle. Just
within the inner orifice the osseous auditory
passage is grooved all round except at its upper
part. This groove is for the reception of the
circumference of the membrana tympani.

In the foetus the osseous portion of the audi-
tory passage is a mere ring of bone, the tym-
panic ring, incomplete at the upper part where
the groove in the adult is wanting. The tym-
panic ring serves as a frame for the membrana
tympani. On the inner surface of the superior
extremity of the anterior crus of this incomplete
ring of bone there is a broad superficial groove,
into which the processus gracilis of the malleus
is received.

By-and-bye the tympanic ring is united to
the temporal bone, and in process of time the
part outside the groove grows outwards so as to
form that plate of bone, thick behind, thin in
front, rolled together in the form of an incom-
plete tube, which in the adult composes the
lower, the anterior, and the posterior walls of
the osseous auditory passage.

ORGAN OF HEARING.

545

The tympanic ring lies immediately behind
the glenoid cavity of the temporal bone, from
which its anterior part is separated by a fissure.
The middle part of this fissure, together with a
line indicating the whole, remains permanent
in the adult, and is known by the name of
fissure of Glasser. Its internal orifice is, in the
adult as it is in the young bone, in the outer
wall of the tympanum, anteriorly of, and close
to the groove for the reception of the membrana
tympani. The fissure of Glasser gives passage
to the ligament, or so-called great external
muscle of the malleus, which is inserted into
the processus gracilis of the malleus. The
chorda tympani does not actually pass through
the fissure of Glasser as commonly described,
but as M. Iluguier* has shown, through a par-
ticular canal, extremely narrow and about half
an inch long, which runs in the line of the
fissure, and opens at the re-entering angle be-
tween the squamous and petrous portions of
the temporal bone.

Membrane of the tympanum, (membrana tym-
pani, Fr. la membrane du tympan ou du tam-
bour,) Germ, das Trommel felt oder Pauken-
J'ell. — A proper membrana tympani exists only
in birds and mammifera. In reptiles there is a
very imperfect representation of one. In birds
the membrana tympani is convex externally, in
the mammifera, on the contrary, it is concave.
The convexity externally in birds forms a very
important distinguishing character of the class.
In the cetaceous mammifera the membrana tym-
pani is thick, and presents a prolongation like
the tube of a funnel into the cavity of the tym-
panum.

The membrana tympani is situated at the
bottom of the external auditory passage, be-
tween which and the cavity of the tympanum
it is interposed like a partition. It is a thin,
semi-transparent, glistening, dry-looking mem-
brane. Its shape is an oval, truncated at one
extremity, the upper. Rather more than the
upper half of its vertical diameter is traversed
by the handle of the malleus, which, when the
membrane is examined on the living subject by
means of the speculum auris, appears directed
from above downwards and backwards.

The longest diameter of the membrana tym-
pani, which is directed from above downwards,
and from behind forwards, is about eight-
twentieths of an inch, and its shortest, that from
behind forwards, somewhat less than seven
twentieths of an inch. It is fixed by its cir-
cumference in the circular groove already men-
tioned, at the inner orifice of the osseous part
of the external auditory passage, or in the foetus,
the tympanic ring; and as in the adult the ori-
fice is cut obliquely from behind forwards,
from above downwards, and from without in-
wards, so is the direction of the membrane.
Hence it forms, with the upper and posterior
wall of the auditory passage, an obtuse angle,
and with the lower and anterior wall, an acute
angle.

Figure 249 represents the adult membrana

* Cruveilhier, Anatomie Descriptive, tome iii.
p. 508.

VOL. II.

tympani of the right side ; a. as seen from the
auditory passage ; b. as seen from the tympa-
num. Its shape, size, the mode in which the
malleus is connected with it, and the cartila-
ginous ring which forms its circumference, are
sufficiently well shown.

Fig. 249.

The membrana tympani does not present
plane surfaces. On the contrary its centre is
drawn inwards, so that it is concave externally,
and convex internally. This disposition of the
membrana tympani depends on its connexion
with the handle of the malleus. The latter being
fixed in its whole length to considerably more
than the upper half of the vertical diameter of
the former, and having an inward direction in-
feriorly, the membrana tympani is, as it were,
drawn inwards to it, hence the concavity ex-
ternally.

As regards the composition of the membrana
tympani, it consists of a proper membrane and
two borrowed layers, one of which, covering
the external surface of the proper membrane, is
a delicate continuation, in the form of a blind
end, of the lining of the auditory passage, and
the other, situated on the inner surface, is
a continuation of the delicate membrane which
gives a lining generally to the cavity of the
tympanum. The latter adheres very closely to
the proper membrane, the other not so inti-
mately, as it readily separates from it by putre-
faction, and can be drawn out along with the
rest of the epidermis of the external auditory
passage in a cul-de-sac.

Structure of the proper membrane. — The pro-
per membrane can be divided into two layers,
an outer thin one, consisting of radiating fibres,
and an inner thicker layer, which is less dis-
tinctly fibrous, though when torn it does indi-
cate a fibrous disposition, and that in a direc-
tion opposite to the former. The radiating
fibres run from its circumference towards the
centre, to be fixed to the handle of the malleus
along its whole extent. Towards the centre
they become stronger, and being, of course,
more aggregated, the layer which they compose
is thicker and more compact in the centre than
towards its circumference. The fibres which
cross the radiating ones are also more aggre-
gated at the centre. They run paiallel with
the handle of the malleus, and turn round
its extremity. At the circumference of the
proper membrane, there is a thick firm ligamen-
tous or cartilaginous ring, (fig. 249,) which
is fixed in the groove of the bone. This liga-
mentous rinsr appears to be formed by an ag-
gregation of the circular fibres interwoven with
the peripheral extremities of the radiating
ones. The pa;t of the membrana tympani
midway between its centre and circumference
is the thinnest.

The radiating fibres have been supposed to
2 o

546

ORGAN OF HEARING.

be muscular by Sir Everard Home and others,
but this has not been confirmed by microscopi-
cal examination.

Mr. Shrapnell* describes at the anterior and
superior part of the membrana tympani, above
the short process of the malleus and its suspen-
sory ligament, and where the groove in the bone
is deficient, a flaccid tissue, composed of irre-
gularly arranged fibres, to which he gives the
name of membrana Jlaccida, in opposition to the
rest of the membrana tympani, which he calls
membrana tensa. This flaccid tissue is more
developed in some of the lower animals, the
sheep and hare for instance, than in man, and
can be readily made to bulge out towards the
auditory passage by blowing air into the Eusta-
chian tube. But we cannot look upon it, with
Mr. Shrapnell, as properly forming any part of
the membrana. tympani. It is merely a mass
of dense, reddish, vascular cellular tissue, sur-
rounding the neck of the malleus, and conti-
nuous with a similar tissue found under the
lining integument of the upper wall of the
osseous auditory passage. It is this same tis-
sue which has been described as a muscle, and
sometimes as a ligament.

The membrana tympani has been said to
present in the natural state a perforation closed
by a valve. Rivinus,f though not the first to
mention it, dwelt on it, however, in a parti-
cular manner, hence the perforation has been
called hiatus Hivinianus. The subject has been
more recently taken up by Wittmann and
Vest.J

The membrana tympani receives a nerve
from the third division of the fifth, which has
communications with filaments of the chorda
tympani.

To resume our description of the cavity of
the tympanum: — In the upper wall of the
tympanum there is an excavation for receiving
the upper part of the incus, and leading from
that, at the upper and back part of the tympa-
num, is a short, wide, triangular canal, with a
rough cellular surface. This is the passage to
the mastoid cells, through the medium of a
large cell, sinuositas mastoidea s. sinus mammil-
laris, s. antrum mammillare, which already ex-
ists in the young bone between the squamous
and petrous portions.

The mastoid cells are cavities in the mas-
toid process, all communicating with each
other. They are quite irregular in regard to
size, number, and relative situation. In early
life, as the mastoid process is not fully formed,
they do not exist, they are only found com-
pletely developed in the adult.

Inferiorly, the cavity of the tympanum forms
a sort of furrow, which presents nothing parti-
cular. It is bounded by the plate of bone
which forms the outer wall of the jugular fossa.

* On the form and structure of the membrana
tympani, in London Medical Gazette, vol. x. p.
120. London, 1832.

t De auditus vitiis, Lipsiae, 1717, 4, p. 32. Tab.
adj. Fig. 1,6. et fig. 2, b.

\ Ueber die Wittmannsche Trommelfellklappe,
in den medizinisch. Jahrbiichern des oestr. Staates.
Bd. v.Wien, 1819, p. 123, 133.

Anteriorly, the cavity of the tympanum
opens into the osseous portion of the Eustachian
tube.

The ossicles or small bones of the ear (ossi-
cula auditus s. aurium, Fr. osselets de /' ouie ;
Germ.dieGehorknochelchen,orGehorbeinchen).
In the upper part of the cavity of the tympa-
num, there are three small bones articulated
with each other, and forming a chain which
reaches from the membrana tympani to the ves-
tibular fenestra. The bones are named malleus,
incus, and stapes, from their resembling more or
less respectively a hammer, an anvil, and a
stirrup iron.

The innermost and most essential is the sta-
pes ; it is it alone which in birds and reptiles
remains, when the others have disappeared, or
been reduced to merely cartilaginous pieces.
The stapes is engaged in the vestibular fenes-
tra.

The outermost of the chain, the malleus, is
in connexion with the membrana tympani.

The hammer bone, (malleus,) Fr. le marteau,
Germ, das Hammer, presents a head, a neck, a
handle, and two processes, one longer, and one
shorter.

The head, caput s. capitulum, is round and
smooth on one surface, and on the other pre-
sents a saddle-shaped depression, surrounded
by a small elevated border. The depression
articulates with the incus, and the border is for
the attachment of the synovial capsule of this
minute joint.

The neck, collum s. cervix, is flattened in one
diameter, and joins the handle at an obtuse
angle.

The handle, manubrium mallei, compressed
from the side corresponding to the articular
depression to the opposite side, and diminish-
ing in thickness towards its extremity, forms,
together with the short process, a double curve,
like an Italic f. The extremity is also com-
pressed, as if beaten flat, but in an opposite di-
rection, so that the broad surfaces of the extre-
mity correspond to the edges of the rest of the
handle.

Short or blunt process, procesms brevis s.
obtusus. From the projecting side of the an-
gle formed by the junction of the neck and
manubrium, this process, which is short, thick
and conical, rises.

The long or slender process, processus longus,
s. gracilis, s. spinosus, s. Folii, springs from the
neck, and from that side of it which corres-
ponds with the non-articular surface of the
head. The long process is of considera-
ble length, and terminates in a broad, flat,
spatula-like extremity, first described by Rau,*
although the commencement or root of the
process itself had been previously delineated
and described by Folius. The long process is
generally found broken off, either from its being
so slender, or from its having been, especially
in old subjects, united to the groove in which it
is lodged.

The anvil bone, incus, Fr. Venclume, Germ.

* Boerhaave Praelect. in Insult., Prop. iv. p.
358.

ORGAN OF HEARING.

547

der Amboss. — This has been compared, also, to
a bicuspid molar tooth. It is divided into a
body, and two processes, or crura.

The body, corpus, presents a concave articu-
lar surface, by which it is joined to the malleus :
around this surface is a groove, (particularly
deep and broad on the side towards the laby-
rinth, that is, the side on which the lenticular
process projects,) for the insertion of the articu-
lar capsule.

The shorter of the two processes, cms s. pro-
cessus superior s. brevis, is blunt at its apex,
and compressed from one side to another.

The longer process, crus s. processus inferior
s. longus, is more slender, and becomes gradually
thinner towards its extremity, where it is slightly
curved, and where it presents, supported on a
short bony pedicle, given off at a right angle
from its side, the lenticular process, processus
lenticularis incudis;* — a small oval plate so
situated, that a line drawn through the long
diameter of it would intersect obliquely a line
corresponding to the long crus of the incus.
The free surface of the lenticular process is
convex, and is destined to articulate with the
corresponding concave surface on the head of
the stapes. The lenticular process has been,
and is still, often described as a separate bone,
under the name of os lenticulare.

The stirrup bone, (stapes). Fr. L'etrier.
Germ. Der Steigbugel. — Exactly like a stirrup,
this bone presents a base, two crura, and a head,
where the crura unite.

The base, basis, the essential part of the bone,
has precisely the same shape as the vestibular
fenestra to which it is applied, only a little
smaller. The arched margin of the base cor-
responds to the upper edge of the fenestra, and
the indented margin to the lower edge.

The surface of the base corresponding to the
vestibular fenestra is slightly convex. The other
surface is grooved ; but the groove is subdivided
by a ridge, which extends obliquely along it
lengthways, and which is continuous at its ex-
tremities with the upper margin of the groove
on the inner surface of one crus, and the lower
margin of the groove of the opposite crus.
The margin of the base projects like a ledge
beyond the insertion of the crura.

Of the two crura, one is shorter and straighter
than the other ; both are grooved on the surfaces
regarding each other, and the grooves are con-
tinued into that just described in the base, in
such a way that the groove of one crus is con-
tinued into one of the divisions, and the groove
of the other crus into the other.

The head, cupitulum, somewhat oblong and
flat, presents a superficial depression on its top,
oblique from above downwards, and from with-
out inwards, for receiving the convex articular
surface of the lenticular process of the incus.
There is sometimes an appearance of a neck
supporting the head.

Position, connexions, and articulations of the
small bones of the tympanum. — The handle of

* Blumenbach, Geschichte, und Beschreibung
der menschl. Knoehen, s. 50, p. 145.

Fig. 250.

Small bones of the tympanum of the left side, mag-
nified considerably more than twice. (From Soem-
merring.)

A is the malleus seen from the side correspond-
ing to the membrana tympani : a. head ; b. articu-
lar surface ; c. neck j d. handle ; e. short process ;
f. long process.

B. The incus seen from its outer surface also :
a. body ; b. articular surface ; c. short crus ; d.
long crus ; e e. lenticular process.

C. The stapes : a. head ; b. neck ; c. anterior
and less bent crus ; d. posterior and more bent crus ;
e. base.

D. A fore-shortened view of the stapes : a. an-
terior and less curved crus ; b. posterior crus, the
two are seen uniting at the head, the articular sur-
face of which is seen; c. base.

the malleus is fixed to the membrana tympani.
The articular surface on the head of the malleus,
to the corresponding surface on the body of the
incus, and the long process of the incus, is
through the medium of its lenticular process
articulated with the stapes. These two joints
are furnished with small articular capsules.

The head of the malleus lies in the upper
space of the tympanum, above the upper margin
of the membrana tympani. Its articular sur-
face is directed obliquely backwards and in-
wards. The surface of the neck, corresponding
to the prominence of the angle which it forms
with the manubrium, is hitched like a shoulder
under the upper part of the circumference of
the inner extremity of the auditory passage.
The handle of the malleus, it has been said,
is compressed from one side to another, so that
it presents two flat surfaces and two edges or
ridges. That edge or ridge which is continued
down from the short process is turned outwards,
and corresponds to the membrana tympani ;
into it, indeed, along its whole extent, the cen-
tral extremities of the radiating fibres of that
membrane are inserted. The extremity of the
handle of the malleus, which is curved forwards
and outwards, is compressed, but in a direction
contrary to the rest of the handle ; so that one
of the flat surfaces, that corresponding to the
outer ridge of the rest of the handle, is con-
nected with the membrana tympani at a point
below its centre, and nearer its anterior edge.
It is at this point that the bottom of the con-
cavity is which the membrana tympani presents
externally. At its upper part the membrana
tympani is pushed outwards by the short pro-
cess of the malleus, which projects towards the
auditory passage.

2 o 2

548

ORGAN OF HEARING.

The long process of the malleus is directed
forwards, and lies in a groove within the anterior
part of that for the reception of the membrana
tympani, and close to the fissure of Glasser.

To the top of the head of the malleus, a
ligament extends downwards from the upper
wall of the cavity of the tympanum. Another
ligament, known also under the name of the
great external muscle of the malleus, proceeds
from the spinous process of the sphenoid bone
backwards and inwards, through the fissure of
Glasser, and is inserted into the long process of
the malleus. A third ligament has been de-
scribed, as arising from within the upper and
posterior margin of the inner orifice of the
auditory passage above the margin of the mem-
brana tympani, and proceeding downwards and
inwards to be inserted into the handle of the
malleus below the short process, close to the
place where the connexion between the handle
of the malleus and the membrana tympani
ceases. Of this ligament, which has also been
described as a muscle, small external muscle of
the malleus, there is not much trace, except in
the reddish cellular tissue already mentioned.

The body of the incus lies in the upper and
posterior part of the tympanic cavity. Its
articular surface, corresponding to that of the
malleus, is directed forwards, and a little up-
wards and outwards. The articulating surfaces
of the two bones are incrusted with cartilage,
and the joint is provided with a synovial mem-
brane, which is strengthened by ligamentous
fibres. The short branch is directed horizon-
tally backwards towards the entrance into the
mastoid cells, and is there fixed by means of a
short and broad ligament, which arises from a
small pit in the outer wall, and embracing its
extremity, is inserted on it. The long branch
extends perpendicularly downwards, almost pa-
rallel with the handle of the malleus, but nearer
the inner wall of the tympanum, towards which
its extremity, bearing the lenticular process, is
curved.

The stapes, situated lower down in the cavity
of the tympanum than the other bones, lies
with its base applied to the vestibular fenestra,
to the circumference of which it is closely fixed
by a circular ligament, ligamentum annulare
baseos stapidis. This ligament springs from the
margin of the vestibular fenestra, and is inserted
into the jutting margin of the base of the stapes
all round. Besides this ligament, there are re-
flections of the membrane lining the tympanum,
and of that lining the vestibule. The con-
nexions of the base of the stapes with the ves-
tibular fenestra are such as to admit of some
degree of movement, but not to any very great
extent, — so little, that it would seem one object
of the mechanism of the fenestra ovalis, and its
closure by the base of the stapes, was merely
to interrupt the continuity of the osseous walls
of the vestibule.

The short branch .of the stapes is in front ;
the long branch behind, and its head outwards,
where it meets and articulates with the lenticu-
lar process of the long branch of the incus.
This articulation presents also cartilages of in-

crustation, and a minute synovial capsule, to-
gether with strengthening ligamentous fibres.

Fig. 251.

The small bones connected together, and their relation
to the osseous labyrinth. Left side. Magnified.
(From Soemmerring . )

Muscles of the small bones. — Some anatomists
admit four muscles : three attached to the mal-
leus and one to the stapes. Of the three at-
tached to the malleus,two are described as having
for their action the relaxation of the membrana
tympani; but these so called laxatores tym-
pani are merely ligaments, and have been de-
scribed above as such. I agree with Hagen-
bach,* Breschet,t and Lincke,} that two muscles
only can be distinctly demonstrated, and these
two are both tensors of the tympanum. A
relaxation, or state of rest of the membrana
tympani, takes place of itself, as Treviranus§
remarks, when the tensors cease to act; hence
a relaxator muscle of the membrana tympani
was not required

Muscle of the malleus, musculus internus
mallei s. tensor tympani. — This muscle occupies
the canal, or half canal, which was described as
lying above the osseous part of the Eustachian
tube. It arises from the posterior and under
part of the sphenoid bone, from the superior
part of the cartilaginous portion of the Eusta-
chian tube, and also from an aponeurotic sheath
which lines the canal, or completes the groove
in which it is lodged. Its fibres proceed from
before backwards, and terminate in a slender
tendon, which bending at a right angle, as a
rope over a pulley, enters the cavity of the
tympanum, through the tubular projection al-
ready described as a continuation of the canal
in which it lies. Having entered the tympanum,
it proceeds outwards, and is inserted into a
slight elevation, sometimes remarked on the
inner and anterior surface of the handle of the
malleus below the long process, and also a
little below and opposite the root of the short

* Disquisitiones anatomicae circa rausculos auris
uiternae hominis et Mammalium, &c. Basileae, 1833,
p. 20.

t Op. cit. s. xxxiii.

\ Das Gehbrorgan, &c. Leipzig, 1837, p. 140,
s. 114.

§ Biologic, Band. vi. p. 376.

ORGAN OF HEARING.

546

process. The muscle of the malleus receives
a nervous branch from the otic ganglion.

By the action of this muscle, the handle of
the malleus is drawn inwards and forwards,
whilst the head is moved in the opposite direc-
tion, in consequence of the bone moving on its
long process as on an axis. The result of this
movement of the bone is, that the membrana
tympani, which is attached to the handle of the
malleus in its whole length, is also drawn in-
wards and stretched. Besides the tension to
which the membrana tympani is thus subjected,
the base of the stapes is forced against the ves-
tibular fenestra, in consequence of the move-
ment communicated by the head of the malleus
to the incus, which tends to press inwards the
long extremity of the latter.

Muscle of the stapes, M. stapedius. — This is
lodged, and takes origin in the cavity of
the pyramid already described. Much paler
and smaller than the preceding muscle, it is
inserted into the posterior and upper part of the
head of the stapes by a slender tendon, which
issues by the aperture in the summit of the py-
ramid, and proceeds downwards and forwards
to its termination.

The stapedius muscle receives a nervous fila-
ment from the facial nerve.

The first effect of the action of this muscle
will be to press the posterior part of the base of
the stapes against the vestibular fenestra. At
the same time the long branch of the incus will
be drawn backwards and inwards, and the head
of the malleus being, by this movement of the
incus, pressed forwards and outwards, its han-
dle will be i a-ried inwards, and the membrana
tympani thus put on the stretch. Breschet
calls the muscle of the stapes a laxator, but I
do not know on what grounds.

Magendie* mentions the circumstance that
in the stapedius muscle of the ox and horse,
there is imbedded a small lenticular bone.
Professor Berthold of Gottingenf has more
lately called attention to the same circumstance.
Berthold has not found this bone in man, nor
sheep, nor deer, nor goats, nor swine. In the
ox and calf it is about one-half to three-fourths
of a line in its longest diameter, and one-third
in the shortest, and lies surrounded by the mus-
cular and tendinous substance where the for-
mer passes into the latter. In the horse it is a
little nearer the lower margin of the muscle and
tendon, and is much smaller than in the ox;
moreover, it is not round, but is a longish plate,
somewhat thicker in the middle.

At the place where the stapedius muscle is
inserted into the stapes, HyrtlJ has sometimes
found in the human ear a small process of bone
which in some cases was so long as to extend

* Sur les organes qui tendent ou relachent la mem-
brane du tympan et la cbaine des osselets de 1'ouie
dans 1'homme et les aniinaux mammiieres. In
Journal de Physiologie experimentale, t. 1., p.
346. Paris, 1821.

t Ueber ein linsenformiges Knochelchen im
Musculus Stapedius mehrerer Saugethiere. In
Mueller's Archiv. Jahrg. 1838.

$ Beitr'age zur patbologiscben Anatomie des
Gehbrorgans, in the Medicin. Jabrbiicher des
k. k. oesti. Staates. Wien 1836. Bd. xx. p.
439.

into the belly of the muscle itself. Teichmeyer*
has described this free bone of the stapedius
muscle as constant in man.

Having described the walls and contents of
the cavity of the tympanum, we come now to
speak of the membrane which lines it.

The lining membrane of' the cavity of the
tympanum is in continuity with the mucous
membrane of the throat, through the F.ustachian
tube. Extremely delicate, and in some parts
very vascular, it is not merely a mucous
membrane, but is theoretically a combination
of periosteum and mucous membrane, being
what Bichat called fibro-mucous. It»in vests all
the elevations and depressions observed on the
walls of the tympanum, and extends into the
mastoid cells. The outer layer of the mem-
brane of the fenestra rotunda, membrana tym-
pani secunduriti, is a continuation of it.

The base of the stapes is fixed by its circum-
ference to the outer edge of the groove, which
encircles the vestibular fenestra, by a membrane
or ligament. The lining membrane of the ves-
tibule, continued over the base of the stapes
from within, also invests the inner surface of
this annular ligament, whilst the outer surface
of it is covered by the membrane lining the
tympanum as it is reflected on the stapes.

The membrane lining the tympanum invests
the small bones and the tendons of their mus-
cles where they run free in the cavity. A fold
of it tills up the space bounded by the crura and
base of the stapes. The chorda tympani, also,
in its passage across the tympanum, is enve-
loped by it. Lastly, it forms the inner bor-
rowed layer of the membrana tympani, cover-
ing and adhering closely to the handle of the
malleus.

The Eustachian tube, (tuba Euntachii, s. ca-
nalis palatinus tympani; Fr. la trompe d'Eus-
tachi ; Germ, die Eustuchische Rohre oder dtr
Gaumeiigang des mittkren Ohrs.) — The
Eustachian lube is a passage of communication
betwixt the cavity of the tympanum and the
throat. In length about an inch and a half, it
is directed from behind forwards, from without
inwards, and from above downwards. Its gut-
tural orifice is wider than that by which it opens
into the tympanum.

Proceeding from the tympanum, its first part
is an osseous canal, the osseous part of the Eus-
tachian tube; the walls of the remainder of it
are composed partly of cartilage, partly of
fibrous membrane, the cartilaginous and mem-
braneous portion of the Eustachian tube.

The osseous part of the Eustachian tube, pars
ossea tuba Eustachii, begins at the anterior and
lower part of the tympanum, by a funnel-like
orifice, and runs forwards and inwards on the
outside of the carotid canal, and below that for
the reception of the internal muscle of the mal-
leus. It is about half an inch in length, and
ends by a notched and irregular edge at the re-
entering angle, between the squamous and
petrous portions of the temporal bone. Its
calibre contracts in its course forwards, and is
compressed from without and below inwards

* Vindiciae quorundam inventorum anat. in liubium
vocatorum. Jeiiae. 1727. 4.

550

ORGAN OF HEARING.

and upwards. In the dry bone it is wide
enough to admit the end of a quill stripped of
its feathery part, about one-twelfth of an inch
thick. In the recent state, when lined by its
mucous membrane, it is very much narrower.

The cartilaginous and membraneous portion
of the Eustachutn tube, pars cartilagineaetmem'-
branacea tub<e Eustachii. — In the skull it is ob-
served that the osseous part of the Eustachian
tube is continuous with a sort of gutter which
is formed by the outer and anterior side of the
petrous bone, and the posterior inner and lower
margin of the great wing of the sphenoid bone.
To this gutter the external wall of that part of
the Eustachian tube under consideration, which
is partly cartilaginous and partly fibre-membra-
neous, corresponds at its tympanic extremity;
towards the guttural orifice of the tube, the
membraneous wall is applied against the circum-
flex muscle of the palate. The inner, and also
the upper wall of this portion of the Eustachian
tube, is formed of a grooved cartilaginous la-
mina of a triangular form, fixed by dense cel-
lular tissue to the irregular extremity of the
osseous portion, to the apex of the petrous
bone, and to the root of the inner plate of the
pterygoid process of the sphenoid. At the
guttural orifice of the Eustachian tube, it forms
a semilunar prominence with its convexity
turned upwards and backwards. The cartila-
ginous plate of the outer wall does not extend
to the mouth of the tube, but only fills up that
place where the outer wall of the bony groove
above-mentioned as continuous with the osseous
part of the Eustachian tube is defective, that is,
from before the foramen spinosum of the sphe-
noid to the scaphoid fossa at the root of the in-
ner plate of the pterygoid process.

The cartilaginous and membraneous portion
of the Eustachian tube is about one inch long.
Being compressed from within outwards, a sec-
tion of it is an elliptical fissure. From its junc-
tion with the osseous portion, it goes on widen-
ing, so that the point of junction is the narrow-
est part of the tube; — in the recent state, about
one-thirtieth of an inch in diameter, just suffi-
cient to admit a small probe.

The mouth of the Eustachian tube in the
throat forms an oval-shaped fissure, about
three-eighths of an inch long, bounded ante-
riorly and posteriorly by prominent swollen
edges. The fissure is directed obliquely from
above downwards, and from before backwards,
and is situated at the upper and lateral part of
the pharynx behind the soft palate. In refe-
rence to the nasal passage, my observation
agrees with that of Kramer,* that the lower
angle of the guttural orifice of the Eustachian
tube lies a very little deeper than the horizontal
line of the lowest meatus, whilst the upper
angle is a little deeper than the horizontal line
of the middle meatus.

The Eustachian tube is essentially a tegumen-
tary canal ; through it atmospherical air is ad-
mitted into the tympanum, a condition which,
by keeping up an equable pressure on either
side of the membrana tympani, and giving free

* Die Erkenntniss und Heilung der Ohrenkrank-
heiten. Berlin, 1836. p. 243.

scope to the play of the small bones upon each
other, is necessary for the perfect exercise of
hearing. Its lining membrane is continuous
with that of the throat on the one hand, and
with that of the tympanum on the other.
At the guttural orifice of the tube, it has all the
properties of the mucous membrane of the
nose and throat ; as it approaches the tympa-
num it becomes thinner and finer, until it
assumes all the characters of the fibro-mucous
lining of the tympanum. Within the osseous
portion of the tube, it no longer presents any of
the mucous glands which are found in the
mucous membrane of the prominent edges of
the guttural orifice, and in that lining the carti-
laginous and membraneous portion — mucous
glands, which perform so important a part in
the economy, and particularly the morbid states,
of the Eustachian tube and apparatus of hear-
ing generally.

Fig. 252.

The two muscles of the small bones, and the Eusta-
chian tube. (From Soemmerring . )

a. b. c. d. Eustachian tube ; e. muscle of the mal-
leus ; f. the muscle of the stapes.

2. The external ear, including the auditory
passage.

A. The auricle or the ear, (auricula s. pin-
na,) Fr. pavilion de Voreille; Germ, das Ohr. —
The human auricle, as is known, presents on
the surface directed outwards, prominences
bounding gutter-like depressions, which wind
like a maze in different directions; but all lead
at last into the auditory passage. Considered
in a general way, the surface directed outwards
is concave. The surface turned towards the
side of the head is, on the contrary, generally
speaking, convex, but it fs depressed at the
places corresponding to the elevations on the
outer surface, and more elevated where the de-
pressions are.

The hem-like fold of the edge of the ear all
round is called helix. The eminence within
the helix is called anthelix, and the gutter-like
depression between the two is called the navi-
cular fossa. At its upper extremity the anthe-
lix divides into two branches, between which is
a triangular depression czlledfossa innominata.
The lower extremity of the anthelix runs into
a projection called antitragus, opposite which,
and under the anterior part of the helix, is a
broad projecting plate called tragus, which
lies over the entrance of the auditory passage

ORGAN OF HEARING.

551

like a valve. The posterior margin of the
tragus, and anterior margin of the antitragus,
meet inferiorly ; but superiorly they are sepa-
rated by a considerable notch. Bounded by
the anthelix, tragus, and antitragus, and tra-
versed horizontally by the commencement of the
helix, is a deep cavity, called concha, at the an-
terior part of which is the auditory passage
leading from it, as the pipe from the mouth of a
funnel. The lower pendulous part of the ear is
called lobule.

Fig. 253.

a. b. c. d. e. the helix ;
f. g. the upper and lower
crura of the anthelix ; h.
the point of junction of
the two crura ; »'. k. the
anthelix ; I. tragus ; m.
antitragus ; n. lobule ; o.
navicular fossa ; p. fossa
innominata ; q. cavity of
the concha ; r. entrance
of the auditory passage.

The auricle of the left side (reduced in size}. ( From
Soemmerring.)

Stripped of the skin which invests it, the
auricle is found to be composed of a cartila-
ginous skeleton, on which its elasticity depends.
The skeleton presents, with some modifications,
all the eminences and depressions we have de-
scribed, except the lobule, which consists merely
of a prolonged fold of skin, between the layers
of which is cellular and adipose tissue.

In the skeleton of the auricle, the helix com-
mences by an acute point in the excavation
of the concha. Gradually becoming broader
and more elevated, it proceeds obliquely up-
wards and forwards, then turning round the
upper margin of the ear, contracts in breadth ;
and about the middle of the posterior margin,
its hemlike fold having ceased, its simple edge
is continued into a free tail-like process of car-
tilage, which is separated by a fissure from the
antitragus. On the anterior part of the helix
above the tragus, there is a mammillary process
of cartilage which gives attachment to a liga-
ment. Behind and below the root of this
mammillary process, there is a small vertical
fissure in the helix, incisura helicis.

Regarding the anthelix there is little more to
be said, except that the lower branch of its
upper extremity forms a very prominent crest ;
and that inferiorly the anthelix is continued into
the same tail-like process that the helix runs
into, and is also partly continued into the anti-
tragus.

The antitragus is a small plate of cartilage,
forming an angle, directed upwards and forwards.
It is continuous by its base with the cartilage
of the concha. The lobule hangs from the
antitragus, and the tail-like process of cartilage
common to the helix and anthelix.

Tragus. — Between the helix and tragus there
is no connexion by cartilage. The space is
merely filled by a continuation of the fibrous
cellular tissue which constitutes the upper and
posterior part of the cartilaginous and mem-
braneous portion of the auditory passage.

The cartilage of the ear is covered by peri-
chondrium, which imparts considerable strength
to it. When the perichondrium is removed by
dissection, the cartilage is found to be very
brittle.

Fig. 254.

a. a. a. a. helix ; b. ant-
helix ; c. two crura of
anthelix • d. cavity of the
concha ; e. antitragus ;
f. tragus ; g. fissure be-
tween the tragus and
commencement of carti-
laginous portion of the
auditory passage, the
larger fissure of Santo-

Skeleton of the cartilage of the external ear (dimi-
nished). (From Soemmerring.)

The skin covering the cartilage of the ear
adheres intimately to its unequal surface, less
so to its back and circumference. The lower
part of the hem-like fold of the helix is formed
entirely by it; also the lobule, as has been
already said. The skin of the auricle contains
a number of sebaceous follicles, particularly in
the concha, and around the entrance of the au-
ditory passage.

On the tragus is observed, especially in old
people, a small tuft of hair, which has been
compared to a goat's beard ; whence the name
lragus,(rgayo$,hircus,) which the Germans trans-
late Bock. The antitragus they call Gegenbock.

Ligaments of the ear. Anterior ligament,
(ligamentum auricula anterius). — This proceeds
from the root of the zygomatic process to the
lower and anterior part of the helix, and to the
tragus.

Posterior ligament, (ligamentum auricula
posterius). — Extends from the outer surface of
the mastoid process to the posterior surface of
the cartilage of the ear, where the concha runs
into the auditory passage. Besides the above
ligaments binding the ear to the head, there are
others which extend from one point of the car-
tilage of the ear to another.

Muscles of the ear. — The muscles of the ear
fall into two classes : viz. those which, arising
from the head, are inserted into the ear, and
move it as a whole ; and those which, extend-
ing from one part of the cartilage to another,
are calculated, were they strong enough, to pro-
duce a change in the general form of the auricle.

Muscles which move the ear as a whole, or the
extrinsic muscles. — The elevator, or superior
muscle of the ear, (M. attollens auriculam s.
superior auricula), is a broad thin muscle,
composed of fibres spread out on the upper part
of the side of the head. It arises from the
middle part of the epicranial aponeuroses, and
also from the temporal aponeuroses ; thence, to
its insertion into that elevation of the ear-carti-
lage on the surface next the head, which cor-
responds to the fossa innominata, the fibres be-
come more aggregated, so that the muscle is
much narrower, but thicker inferiorly than su-
periorly. By elevating the upper part of the

552

ORGAN OF HEARING.

ear, it will widen and straighten the auditory
passage.

The retractor or posterior muscles of the ear,
( M. retrahentes avriculam, s. posteriores auri-
cula.) These ordinarily consist of three bundles,
sometimes only two, which, taking their origin
from the mastoid process, run forwards to the
cartilage of the ear, into which they are inserted
at the eminence on the back of the concha,
corresponding to the commencement of the helix
on the other side.

In drawing the ear backwaids, these muscles
w il dilate and flatten the concha, and widen
the entrance to the auditory passage.

The anterior muscle oj the ear, ( M. attrahens
auriculam s. anterior auricula,) arises from the
zygomatic process, and, in its course backwards
to the ear, gradually contracts, until it ends in a
short tendon, which is inserted into the anterior
surface of the helix, immediately above the
tragus. It draws the ear forwards.

Fig. 255.

where the helix rises from the concha, and is
inserted into the posterior margin of the ascend-
ing portion of the helix.

The muscle of the tragus, Cm. tragicus). — Of
an oblong square form, this muscle covers the
outer surface of the tragus, from the lower part
to the upper margin of which its fibres run. •

The muscle of the antitragtu, (m. antitragi-
cus). — The fibres of this muscle arise from the
outer surface of the antitragus, and are inserted
by a small tendon to which they converge into
the lower extremity of the anthelix.
Fig. 256.

a. m. helicis major;

c. m. helicis minor ;

d. m tragicus ; e. m.
antitragicus.

The intrinsic muscles situated on the concave side of
the auricle (diminished). (From Soemmerring ).

The transverse muscle of the ear, (m. trans-
versus auricula,) is situated on the back of the
ear. It is composed of fasciculi not very dis-
tinctly muscular, which run from the dorsum of
the concha to the back of the anthelix, and the
elevation which corresponds to the navicular
fossa.

Fig. 257.

a. transversus mus-
cle ; b. helix ; c. back
of the concha ; d. tra-
gus; e. fissure of Saa-
torini.

The cartilage of the left auricle from behind, and
the extrinsic muscles (diminished). (From Soemmer-
ring).

a. m. attollens auriculam ; 6. m. anterior auri-
culae ; c. d. two m. retrahentes auriculam.

Intrinsic muscles of the ear. — These muscles
are very delicate and weak, little adapted to
produce any sensible change in the form of the
ear. Five are admitted : —

The larger muscle of the helix, (M. helicis
major,) arises from the lower arid anterior part
of the helix, on the outer and anterior surface
of which it ascends for about three quarters of
an inch, and then is inserted into the helix above
the point where the ear becomes free from its
attachment to the head.

The smaller muscle of the helix, (M. helicis
minor.) — This lies farther down and more be-
hind than the preceding. It begins at the place

The back of the cartilage of the' external ear and
the transversus muscle (diminished), ( From Soemmer-
ring).

E. The external auditory passage, (meatus au-
ditor ius externus s. porus acusticus; Fr. Le con-
duit audit if ou auriculaire; Germ. Der Gehur-
gang.) — Like the Eustachian tube, the external
auditory passage is composed of an osseous
portion, and a portion partly cartilaginous and
partly membraneous. The osseous portion has
been already described as a part of the outer
wall of the tympanum; the other portion comes
to be noticed here as a continuation of the car-
tilage of the auricle. The passage will then be
considered as a whole.

Cartilaginous and membraneous portion of
the external auditory passage, meatus auditorius
cartilagineus-membranaceus. This portion of
the auditory passage, about half an inch long, is
formed in front and below by cartilage, above

ORGAN OF HEARING.

553

and behind by dense fibro-membraneous cellu-
lar tissue, in which many ceruminous glands are
imbedded.

The plate of cartilage which forms the an-
terior and lower wall of this portion of the
auditory passage is of a triangular shape with a
fissure running through its base to near the apex.
The base is below ; the apex above. The base
corresponds to the anterior surface of the mas-
toid process. One side is attached to the
anterior and lower part of the circumference
of the outer extremity of the osseous passage,
by dense and strong cellular tissue. The other
side corresponds to the base of the tragus.
The apex or angle formed by the two sides
runs into the upper part of the base of the
tragus, and corresponds to the root of the
zygomatic process. The angle formed by the
base, and that side which is attached to the
osseous part of the passage, is extended into
a broad pointed tongue, which is fixed into the
deep and rough depression at the lowest part
of the margin of the orifice of the osseous
passage. The angle formed by the base and
the other side is continued into the concha.

The dense fibrous cellular tissue, which
completes the passage above and behind, ex-
tends from the cartilage of the concha to the
upper and posterior part of the margin of the
external orifice of the osseous part of the passage.

What are called the fissures of Santonm,
incisurcB Santorinir^ue, are: — 1. that fissure
extending through the base of the triangular
plate of cartilage to near its apex ; and 2. that
between the outer margin of the cartilage and
the base of the tragus. These fissures are
closed by fibrous cellular tissue which, particu-
larly over the second fissure, appeared to San-
torini to consist of muscular fibres. These
fibres have, therefore, received the name of the
muscle of the largest fissure, or the muscle of
Santorini, m. incisurte inujoris s. Santorini.
Haller considered their action to be, by ap-
proximating the cartilaginous pieces, to shorten
the length of the passage.

Viewed as a whole, the auditory passage is a
canal of an oval calibre. It leads from the
auricle to the tympanum, from the cavity of
which it is separated by the interposition of the
membrana tympani. In front of it lies the
joint of the lower jaw, behind is the mastoid
process. In the adult its length is about an inch
and a quarter, and its direction is at first some-
what forwards, then upwards and backwards,
and lastly downwards and forwards again. Its
lower wall is from one-tenth to one-fifth of an
inch longer than the upper.

The auditoiy passage is lined by a continua-
tion of the skin of the auricle. This skin be-
comes more and more delicate as it approaches
the osseous part of the passage, — extremely so
where it is continued on the outer surface of
the membrana tympani. The skin of the audi-
tory passage is covered with fine hairs, and in
old persons close to the entrance, hairs like
those on the tragus, sometimes of considerable
length, are enrooted.

The skin of the auditory passage is connected
to the subjacent cartilage and bone by rather

dense and sparing cellular tissue. The epider-
mis readily separates by putrefaction, and may
be drawn out like the finger of a glove, the
blind end being the part which forms the outer
borrowed layer of the membrana tympani.

From about a tenth of an inch within the
auditory passage to about one-fifth of an inch
from the membrana tympani, the lining integu-
ment is perforated by numerous small aper-
tures, the terminations of the excretory ducts of
the glands which secrete the ear-wax. These
excretory orifices are most numerous about the
middle of the passage, towards the termination
of the cartilaginous and membraneous portion.

The ceruminous glands, glandules cerumi-
noste, are small round or oval bodies of a
brownish yellow colour, and very vascular.
They are imbedded in the areolse presented by
the dense cellular tissue which connects the
skin of the auditory passage to the subjacent
cartilage or bone.

The ear-wax, cerumen, is, as is known, a
thick orange-coloured or yellowish brown viscid
substance, of an extremely bitter taste, and
somewhat aromatic odour. When first secreted,
it is a thin yellowish milky fluid. (See CERU-
MEN.)

The auditory passage, especially in the
middle, is usually covered with a more or less
thick layer of it. It consists principally of a
butter-like fat and albumen in combination with
a peculiar animal matter; of a yellow, bitter,
alcoholic extractive matter, with lactate of potass
and lime and a watery extractive matter.

In irritation or diseased states of the glands,
the ear-wax is changed in its properties, and is
thrown out in larger quantities than usual, so
that it collects and comes sometimes to fill
completely the auditory passage, and thus give
rise to dulness of hearing.

Fig. 258.

Horizontal section of the auditory passage (dimi-
nished). (From Soemmerring ).

a. Skin of the face in front of the ear ; b. lobule
of the auricle ; c. the antitragus ; d. the tragus cut;
e. anthelix ; f. helix ; g. anterior part of the osseous
auditory passage, cut ; h, h. anterior part of the
cartilaginous portion of the passage, cut ; i. poste-
rior part of the cartilage of the ear ; A. membrana
tympani ; /. section of the mastoid process ; m.
dura mater ; n. skin behind the ear. It is seen
continued over the auricle, and from that into the
auditory passage ; 0. first or greater curve of the
auditory passage ; the end of which is directed for-
wards ; p. the second or smaller curve, directed
backwards •, q. third and smallest curve ; at o. and
p. are seen the orifices of the ceruminous glands.

554

ORGAN OF HEARING.

Nerves of the accessory parts of the apparatus
of hearing.

Nerves of the tympanum. — The tympanum
receives nerves from different sources — from
the fifth, the seventh, eighth, and ninth pairs of
cerebral nerves. Moreover, its nerves have
communication with the sympathetic system.

The facial nerve or portio dura of the seventh
pair rises from the brain by two roots, which
unite together in the meatus auditorius inter-
nus, but before uniting, the smaller root sends
of}' a delicate filament, which forms a commu-
nication, as has been mentioned, with the au-
ditory nerve. This communication, first pointed
out by Swan, has recently been very fully in-
vestigated by Arnold. According to the latter,
in the middle or at the bottom of the internal
auditory meatus, one or several delicate fila-
ments go off from the smaller branch of the
facial, and join the auditory nerve. After this
the facial nerve enters the aqueduct of Fallo-
pius, and issues from the cranium through the
stylo-mastoid hole. In this course it receives,
at the place where it forms the knee-like bend
into the aqueduct of Fallopius, the superior
branch of the Vidian or superficial petrosal
nerve, nervus petrosus superjicialis, s. major.

The superficial petrosal nerve conies off,
along with the inferior branch of the Vidian or
deep petrosal nerve, from the posterior part of
the spheno-palatine ganglion or ganglion of
Meckel. Leaving the deep petrosal nerve at
the posterior orifice of the Vidian canal, the
superficial petrosal proceeds upwards through
the cartilaginous substance in the foramen lace-
rum medium, and then runs backwards in the
groove on the anterior surface of the petrous
bone leading to the hiatus of Fallopius.
Having entered the latter, it joins the facial
nerve, and forms, with its external fasciculi, a
gangliform swelling, intumescentia ganglifor-
mis nervij'acialis, of a grayish appearance and
soft consistence.

From this swelling a filament arises by one
or two roots, and runs backwards into the in-
ternal auditory passage to join the upper por-
tion of the auditory nerve, where the first fila-
ment joined, and forms with it a small reddish
§ray elevation, known to and delineated by
carpa.

Another branch, which arises from the gan-
glionic swelling, is the chorda tympani. The
chorda tympani thus in reality derives its origin
both from the facial and the superficial petrosal
nerves. The chorda tympani accompanies the
facial nerve along the aqueduct of Fallopius
till within a little of the exit of the latter by the
stylo-mastoid hole. The chorda tympani then
leaves the facial nerve at an acute angle, and
proceeds upwards in a proper canal in the
bone, enters the cavity of the tympanum by the
opening just within the posterior part of the
groove for the membrana tympani already de-
scribed. From this opening it proceeds for-
wards between the long process of the incus
and the handle of the malleus, to the fissure of
Glasser, through the canal beside which, already
described, it makes its exit from the cavity of
the tympanum. It then descends by the inner

side of the ascending ramus of the lower jaw,
and joins at an acute angle the lingual nerve.
In its passage across the cavity of the tympa-
num, the chorda tympani anastomoses by one
or several filaments with the nerve which the
fifth pair sends to the membrana tympani.

Fig. 259.

The membrana tympani from within, and tJie course
of the chorda tympani across the tympanum, together
with the connexions of the malleus and incus (magni-
fied). (From Soemmerring ).

a. Membrana tympani ; b. handle of the malleus
and tendon of the internus mallei cut near its in-
sertion ; c, c. the chorda tympani.

To return to the facial nerve. It gives off,
a little below the pyramid, a branch to the sta-
pedius muscle.

The pneumogastric nerve, in its passage
through the base of the skull, forms a small
ganglion, from which springs a nerve which
goes to the ear, ramus auricular is nervi vagi.
This nerve is joined by a filament from the
petrous ganglion of the glosso-pharyngeal ; it
then runs, according to Arnold, in a groove in
the jugular fossa, and at last arrives at the
aqueduct of Fallopius. Here it divides into
three branches, the smallest of which runs up-
wards in the aqueduct of Fallopius towards
the origin of the facial nerve, and unites with
it; the second branch, which is somewhat
larger, runs downwards, and also anastomoses
with the facial. The third and most considera-
ble branch will be noticed along with the
nerves of the auricle and auditory passage.

The nervous anastomosis in the tympanum. —
The principal nerve of this anastomosis is the
nerve of Jacobson, or tympanic nerve of Arnold.

The tympanic nerve, nervus tympanicus, ex-
tends between the petrous ganglion of the glosso-
pharyngeal nerve and the otic ganglion or gan-
glion of Arnold. To follow it from the glosso-
pharyngeal, we find it arises from the upper
part of the petrous ganglion, along with another
filament, which goes to communicate with the
ganglion cervicale supremum, and also with the
pneumogastric. The tympanic nerve enters,
by the tympanic canal already described, the
cavity of the tympanum. Here the nerve ap-
pears near the anterior margin of the fenestra
rotunda, traverses the groove on the promon-
tory, arrives in front of the vestibular fenestra,
then enters the proper osseous canal, into which
the groove on the promontory is continued su-

ORGAN OF HEARING.

555

periorly, and which opens on the surface of the
petrous bone outside, and in front of the hiatus
of Fallopius. From this the nerve advances
between the anterior margin of the petrous
bone and the posterior angle of the great wing
of the sphenoid, between the internal muscle
of the malleus and the superficial petrosal
nerve. There it approaches the nerve of the
internus mallei, and proceeds parallel with it,
and under the name of nervus petrosus superfi-
cial^ minor Anwldi,* goes to join the otic
ganglion.

Fig. 260.

Nervous plexus of the tympanum (from Breschet.)'^

a. Internal carotid artery ; b. glosso-pharyngeal
nerve ; c. petrous ganglion of the same nerve ;
d. the principal trunk of the nervous plexus of the
tympanum which extends to join, e. the otic gang-
lion or ganglion of Arnold ; f, lower maxillary
nerve to which the ganglion adheres ; g. filaments
of communication between the nerve of Jacobson
and the carotid plexus; h. carotid plexus; i. fila-
ment to the fenestra rotunda, or cochlear fenestra ;
k. filament to the vestibular fenestra; /.filament
going to anastomose with the facial nerve ; m. fila-
ment running alongside the Eustachian tube ;
7i. portio dura of the seventh pair ; o. chorda tym-
pani cut ; p. nervous filament from the otic gang-
lion to the muscle of the malleus.

The branches given off and the communica-
tions formed by the tympanic nerve in the course
described, are the following. On entering the
tympanum, the tympanic nerve divides into
two branches, a lower and an upper. The
lower branch first gives twigs to the Eustachian
tube, and then passes out of the cavity of the
tympanum into the carotid canal, through a

* Bidder (Neurologische Beobachtungen. Dor-
pat, 1836,) has recently discovered a new nervus
petrosus superficialis, which, for the sake of distinc-
tion, he calls tertius. It proceeds from the plexus
accompanying the middle meningeal artery into the
cavity of the cranium, passes through a proper fis-
sure in the anterior surface of the petrous bone and
under the entrance of the canal of Fallopius into
the petrous bone to join the facial. It is not always
present.

passage in the bone, where it anastomoses with
the sympathetic nerve. The upper branch, the
continuation of the nerve, gives a twig to the
secondary membrana tympani. According to
Varrentrapp, there arises from it, by two roots,
a twig which runs on the inner wall of the
cavity of the tympanum, then into the Eusta-
chian tube, the cartilage of which it penetrates
anteriorly, and at last loses itself in the mucous
glands around its guttural orifice. A little
higher up a third branch goes to the vestibular
fenestra, and, according to Lauth, the tympanic
nerve receives, immediately on its entrance into
the canal in the upper part of the petrous bone,
a filament from the facial nerve. Moreover,
the tympanic nerve receives a filament of com-
munication from the external branch of the
nervus caroticus, the anterior and stronger
branch of the first cervical ganglion of the sym-
pathetic.

From the otic ganglion a nerve goes to the
internal muscle of the malleus, ramus ad ten-
sorem tympani. It arises from the upper and
posterior part of the ganglion, and runs back-
wards on the inner side of the middle menin-
geal artery to the muscle.

2. Nerves of the auricle and auditory pas-
sage.— The auricle and auditory passage derive
their nerves from the cervical plexus, from the
facial, from the third branch of the fifth pair,
and also from the pneumogastric.

The nerve from the cervical plexus is the
great auricular nerve, nervus auricularis mag-
nus. It comes off from the anterior branch of
the third cervical nerve, and is distributed
principally to the skin on the back of the
auricle and to the posterior muscles. One
branch passes between the antitragus and the
tail-like process of the helix to the other surface
of the ear and ramifies there.

The facial nerve on its exit from the stylo-
mastoid hole gives off the posterior, inferior or
deep auricular nerve, nervus auricularis pos-
terior, profundus inferior, which receives a
twig from the pneumogastric and another from
the great auricular branch of the third cervical
and then divides into two branches, a posterior
larger, and an anterior smaller. The former
gives twigs to the skin of the mastoid process
and the retrahentes auriculam muscles, the
latter spreads on the lower and posterior part
of the cartilaginous auditory passage and the
concha, giving twigs to the skin of these parts
and the retrahentes auriculam. It sometimes
sends a branch through the cartilage into the
auditory passage to ramify in the integument
lining that part.

The temporal branches of the facial nerve
send filaments to the skin of the anterior part
of the auricle, and to its anterior and superior
muscles.

The superficial temporal nerve, a branch of
the posterior and inferior fasciculus of the third
division of the fifth pair, gives off two branches,
nervi meatus audUorii externi, inferior et supe-
rior, the ramifications of which are distributed
to the integument of the auditory passage and
concha. There is one branch, nervus tympani,
which runs under the upper wall of the osseous

556

ORGAN OF HEARING.

auditory passage to the membrana tympani,
between the layers of which it glides and sepa-
rates into very delicate filaments, by one or two
of which it anastomoses with the chorda tym-
pani. The last branch of the superficial tem-
poral nerve sends filaments to the auricle and
its anterior and superior muscles.

The third and most considerable branch of
the auricular nerve of the pneumogastric,
ramus auricularis nervi vagi, gets into the cana-
liculus mastoideus of Arnold, through an open-
ing near the lower aperture of the canalis chorda
tympuni. It heie divides into two branches,
one of which joins, as has been said, the pos-
terior auricular branch of the facial nerve; the
other, which is stronger, arrives at the posterior
wall of the external auditory passage, gives
filaments to the cerummous glands, and in
company with a branch of the posterior auricu-
lar artery penetrates the cartilage of the ear to
ramify on the skin covering its convex surface.
Arteries of the external ear and tympanum.
The posterior auricular artery. This sup-
plies branches which ramify on the convex
surface of the auricle, and also turn over the
helix to spread out on the other surface. Twigs
are also given off to the auditory passage.

A remarkable branch of the posterior auri-
cular is the stylo-mastoid artery. This enters
the stylo-mastoid hole and runs along the
aqueduct of Fallopius, and ends by anasto-
mosing with a branch of the middle meningeal,
called the Vidian artery, which enters by the
hiatus of Fallopius. In its course the stylo-
mastoid artery transmits twigs to the mastoid
cells, the external auditory passage, the mem-
brana tympani, the stapedius muscle, and the
external semicircular canal.

The twig to the membrana tympani is called
arteria tympanica superior. This artery, toge-
ther with the arteria tympanica inferior from
the internal maxillary, supplies the membrana
tympani. The arteries run round the circum-
ference of the membrane and down along the
handle of the malleus, and branching out form
by their inosculations a fine net-work.

The temporal artery sends branches to the
anterior part of the auricle, the external auditory
passage, and to the ceruminous glands. It also
gives off a branch which enters the tympanum
by the fissure of Glasser, and ramifies in the
mucous membrane of the outer wall of that
cavity.

The occipital artery gives twigs to the auricle.
The internal maxillary artery. — This artery
gives off a branch to the joint of the lower jaw,
a twig of which, the arteria tympanica inferior,
just mentioned, passes through the fissure of
Glasser into the tympanum and inosculates on
the membrana tympani with the twigs of the su-
perior tympanic artery of the stylo-mastoid. The
internal maxillary also sends a branch, the deep
auricular artery, arteria auricularis profunda,
to the cartilaginous portion of the auditory
passage, where it supplies the lining integu-
ment and glands. It moreover sometimes gives
small branches to the Eustachian tube.

The middle meningeal artery in the first part
of its course gives branches to the Eustachian

tube. In the cranium it sends a branch, arteria
Vidiuna, into the Fallopian canal, which has
been already described as anastomosing with
the stylo-mastoid. It also sends branches to
the tympanum, which ramify in the mucous
membrane of that cavity and in the muscles of
the small bones.

The accessory middle meningeal artery, when
present, gives branches to the Eustachian tube.
The inferior pharyngeal artery also gives
branches to the Eustachian tube, to the pyramid
and cavity of the tympanum. The Eustachian
tube also receives twigs from the inferior pala-
tine branch of the facial artery.

The internal carotid, before entering the
cranium, sometimes gives a small twig to the
Eustachian tube and sends another, through a
small passage leading from the carotid canal
into the tympanum, to the promontory.

In some animals, such as the mole, the
squirrel, the guinea-pig, the marmot, &c. there
is an osseous canal like a bar of bone extending
over the vestibular fenestra and running through
between the crura of the stapes. This was
first observed by Sir Anthony Carlisle in the
marmot and guinea-pig, who describes it as
" an osseous bolt to rivet it (the stapes) to its
situation."* The canal is for the passage of an
artery and nerve which in some other animals
are unprovided with an osseous canal in their
course through the stapes. The artery running
through the stapes was observed about ten
years ago by Professor Ottof in hybernating
animals; but Professor Hyrtl of Prague}; has
shewn that the artery is by no means peculiar
to those animals, as it does not occur in all,
and as it occurs in animals which do not hyber-
nate.

Mr. Shrapnell § describes in the human ear
an artery accompanied by a nerve, passing
through the membrane which fills up the space
between the arms of the stapes. Mr. Shrapnell
was led to this observation from what he had
seen in the rat, viz. a nerve and artery passing
through the stapes and supported by a minute
channel of bone. Professor Hyrtl || has more
recently described three modes of distribution
of the arteries in man, which he has met with,
analogous to the artery running through the
stapes in the animals above mentioned.

The arteries of the external and middle ear
are accompanied by corresponding veins. As
to lymphatics, there are some small glands
behind the auricle and in front of the mastoid
process. The lymphatic vessels of the external
ear accompany the arteries and veins, but prin-
cipally the latter. Little or nothing is known
of the lymphatics of the tympanum.

* On the Physiology of the Stapes in Philosoph.
Trans. 1805, p. 204.

t Nova Acta Acad. Caes. Leop., torn. xiii.
p. 662.

\ Ueber die Analogien der durch den Steigbugel
verlaufenden Arterie, &c. in Medicinische Jahr-
biicher des oesterreichischen Staates, Bd. xix.
p. 457, Wien 1836.

§ On the Nerves of the Ear, in London Medical
Gazette, vol. x. p. 507, 1832.

II Loc. cit.

ORGAN OF HEARING.

557

III.

1. Development and irregular conditions of the

organ of hearing.

A. Development and irregular conditions of
the ear-bulb. — Our knowledge of the early for-
mation of the ear-bulb is not very precise. This
much we know, that it has quite a separate
origin from the rest of the apparatus of hearing.
Hence, in the irregular conditions of the organ
depending on defective development, there is
no constant and necessary relation betwixt the
labyrinth and the accessory parts of the ear;
for the latter may be imperfect while the former
is in its natural state, and vice versa. In many
cases, however, it has been found that imper-
fect development of the one attended an irre-
gular condition of the other. The earlier a
part is formed the fewer deviations it is subject
to, so a greater number of malformations affect
the accessory parts than the ear-bulb, as the
former are developed subsequent to the latter.

The development of the ear-bulb commences
very early, soon after the appearance of the
eye. It takes place by the springing forth of
the auditory nerve in the form of a tubular
prolongation of the brain. At its central ex-
tremity the cavity of the cerebral prolongation
is continuous with that of the fourth ventricle.
Its peripheral extremity, which extends into
the muscular layer of the embryo, and particu-
larly into the osseous part of it, forms a vesi-
cular dilatation which is gradually separated
from the brain. To this vesicle of nervous
substance, which is the labyrinth, there grows
inwards a reflection of the tegumentary layer to
form the accessory parts of the organ of hearing.

Such is Baer's account of the development
of the ear in the chick. Huschke, on the con-
trary, says that the membraneous labyrinth does
not arise from the brain, but is originally a
blind sac of the skin with an excretory duct,
which gradually contracts, until the blind sac
of skin is completely cut off from the rest of
the tegumentary system.

However this may be, the labyrinth, accord-
ing to the observations of Valentin* made on
the embryo of the sheep, exists at a very early
period, under the form of a simple elongated
tube with an oblong cavity, which is the ves-
tibule. This cavity becomes broader, assumes
a rounder form, and presents in the interior a
somewhat uneven surface. Soon after this, its
inner end is elongated and begins to make a
circular turn, which is the first rudiment of the
cochlea. The turns of this cochlear vesicle be-
come gradually more developed. A short time
after the commencement of the development of
the cochlea, the semicircular canals begin to
show themselves as processes or diverticula of
the vestibule. There first appears the posterior
over and behind the vestibular fenestra ; it be-
comes elongated from within and below out-
wards and upwards, then bending in the form
of an arch returns to the vestibule. In a si-
milar manner the superior and inferior semi-
circular canals are formed. The semicircular

* Handbuch der Entwickelungsgeschichte des
Menscheu, p. 206.

canals are at first proportionally rery wide, but
gradually contract, till at last the ampullae pre-
sent the only trace of their former width. The
vestibule itself has diminished in breadth and
length, and acquired a more trapezoidal form.
The vestibular fenestra, which was before not
very distinct and still round, has become more
evident and exhibits an oval shape.

What Valentin here describes is only the
basis of the future osseous labyrinth. There
exist as yet no observations bearing on the mode
of development of the membraneous labyrinth.

The irregular conditions which the labyrinth
has been found to present, as well as the struc-
ture permanent in the lower animals, corre-
spond in a remarkable manner with the above-de-
scribed stages of development. Thus in a mon-
strous foetus, Hyrtl* found, instead of a vestibule,
cochlea, semicircular canals, and internal mea-
tus, a single very capacious cavity, containing a
membraneous sac, in which the auditory nerve,
sufficiently well developed, terminated. There
was no trace of vestibular or cochlear fenestra,
and the accessory parts of the organ were en-
tirely wanting. Rodererf describes a somewhat
similar case, in which, however, some of the
accessory parts presented themselves, though
in a very rudimentary and imperfect form.

The cochlea has presented itself as a mere
subdivision of the vestibule without any wind-
ings, a state of parts which is permanent in
birds. In other cases, though presenting wind-
ings, these have been found fewer than natural,
and sometimes the spiral lamina has been
wanting or not extending throughout all the
turns of the cochlea, so that no subdivision
into scalae or but a very imperfect one pre-
sented itself. The semicircular canals are
sometimes smaller and narrower than usual;
one or all of them have been found wanting or
but partially present. In the latter case, after
running a short way, they have been observed
stopping short and terminating in a cul-de-sac.
The semicircular canals, as they are formed
later, more frequently present deviations from
the regular structure than the vestibule and
cochlea.

Our knowledge of the ear-bulb in the human
embryo commences at about the third month,
when the membraneous labyrinth is already
very perfectly developed and surrounded by a
cartilaginous shell, having a structure as com-
plicated as at a more advanced period the bony
shell presents. The membraneous labyrinth is
at this early period so firm that it is not very
difficult, by means of careful dissection and
manipulation, to extract the whole from its
cartilaginous case.

According to Meckel,J the membraneous la-
byrinth is composed at first of two perfectly

* Beitrage zur pathologischen Anatomie des
Gehororgans. In the Medicinische Jahrbiicher,
des k. k. oestr. Staates. Wien, 1836. Bd. xx.
p. 446.

t Descriptio foetus parasitic!. In Commentariis
Soc. reg. Goettingensis. torn. iv. 1754, pp. 136 —

\ Manuel d'Anatomie, etc. traduit par Jourdan
et Breschet, tome iii. s. 1948— 3« Paris, 1825.

558

ORGAN OF HEARING.

distinct membranes, the one simply inclosed
within the other, but not connected farther.
The inner membrane is thinner but firmer and
more elastic than the outer. The latter, which
does not adhere to the cartilaginous case any
more than it does to the osseous labyrinth
which succeeds it, gradually becomes thin,
until at the seventh month there is no longer
any trace of it. The inner membrane, on the con-
trary, becomes proportionally thicker and firmer.

Meckel has never found the membraneous
labyrinth in a more simple form, nor has he
been able to determine whether it ever exists
naked in the cranium.

At a very early period the pulpy mass of
the auditory nerve becomes converted into
nervous bundles, and grows either by lateral
additions or by an increase of its filaments.
The cochlear part of it, according to Valentin,*
lies free in the tube of the cochlea under the
form of a thick white cord; it follows the turns
of the cochlea, but gives no considerable la-
teral fibrils to the walls of it. As to how the
auditory nerve ends in the membraneous laby-
rinth at this period nothing is known.

In an anencephalous foetus described by
Hyrtl,t the cochlea was represented by a ca-
vity, from the base of which, corresponding to
the internal meatus, there rose a pyramid com-
posed of canals and extended to the roof of it.
This pyramid and the canals composing it were
the representative of the axis and its canals for
the transmission of the fibrils of the cochlear
nerve. There was no trace of a turn of the
cochlea nor of a lamina spiralis.

We now enter into a more explored region,
viz. the progress of ossification in the laby-
rinthic shell, and for the knowledge we possess
on the subject we are chiefly indebted to the
late J. F. Meckel.J

The osseous labyrinth is at first merely mem-
braneous; by-and-bye it becomes cartilaginous,
and lastly ossifies. The membraneous laby-
rinth has not been properly distinguished from
it. The former at first lies free in the cavity
of the cranium; the latter has never been ob-
served in an uncovered state.

The development of the osseous labyrinth is
quite distinct from the formation of the bony
substance of the petrous bone. The latter com-
mences before the former.

Ossification commences in the labyrinth to-
wards the end of the third month round the
fenestra rotunda, first at the upper part, then
at the lower part ; and when a ring of bone has
thus been produced, ossification extends for-
wards. At the same time that the process just
described takes place, another osseous nucleus,
quite distinct from the preceding, is developed
at the outer extremity of the superior vertical
semicircular canal ; there then appears a third
small scale nearly in the middle of the posterior
vertical semicircular canal. Proceeding from
the first nucleus of bone, ossification makes
rapid progress backwards and downwards;

* Op. cit. p. 208.
t Op. et loc. cit.
$ Op. et loc. cit.

whence the floor of the labyrinth is formed*
The second nucleus enlarges perhaps even
more quickly than the first, so that the whole
superior vertical semicircular canal is soon os-
sified, with the exception of its lower concave
surface. From the inner extremity of this se-
micircular canal ossification extends on the
inner surface of the petrous bone, circum-
scribes the internal auditory meatus, penetrates
into its interior, and forms the base of the
cochlea. In the fifth month ossification ex-
tends from the two first nuclei to the horizontal
semicircular canal.

In the ossification of the cochlea, that of the
petrous bone has but a very small share. All
that the petrous bone contributes is merely a
thin prolongation which it sends between the
turns of the cochlea. This process is at first
broader than at a subsequent period. From
the third month, as the cochlea widens from
without inwards, the process in question be-
comes thinner, and, at the same time, are deve-
loped the less considerable projections which
separate externally the first external turn and a
half of the cochlea from each other.

The ossification of the labyrinth has been
found imperfect; thus Krombholz* relates a
case in which he found the semicircular canals,
as well as both scalae of the cochlea, presenting
the same thinness of walls as is remarked in the
foetus. Some places were merely membraneous.
I have already mentioned that the aqueducts
are sometimes unusually wide, a circumstance
conceivable when we consider the mode in
which most likely they are developed, and
which was spoken of when considering them.
In certain of the lower animals, such as the
pig, they are naturally wide.

At first the osseous labyrinth is quite dis-
tinct from the mass of the petrous bone, in
which it is, as it were, embedded. Its outer
surface is, up to the fifth month, quite smooth;
the corresponding inner surface of the osseous
mass of the petrous bone is smooth also, but
not so much so. The two surfaces are soon
confounded together,al though the spongy cellular
structure of the petrous bone can still, even for
some time after birth, be easily enough removed
from around the hard bony substance of the laby-
rinth. Afterwards they become inseparable,
though it is still possible to perceive a trace
of the line of demarcation between them,
especially in the cochlea.

All the above circumstances show that the
osseous labyrinth, though in the petrous bone,
is not of it; and that, as has been already said, it
cannot be affirmed tobelongto the skeleton, but
to be merely embedded in a bone which does.
Moreover as Weberf remarks, the osseous laby-
rinth is not in all animals enclosed in the same
bone of the skull ; for in fishes, when a trace of the
osseous labyrinth is yet to be found, the semi-
circular canals, or the rudimentary representa-
tive of them, are situated in the occipital bone.

* Miicke, kurze Uebersicht der gegenwaitig be-
stehenden Lehr-und-Erziehungsanstalten fur Taub*
stumme u. s. w. Prag. 1827, p. 19.

t Hildebrandt's Anutomie. Bd. iv. p. 40.

ORGAN OF HEARING.

559

B. Development and irregular conditions of
the tympanum and external ear.

1. Of the tympanum and its contents.

1. The cavity of the tympanum. — A prolon-
gation or diverticulum of the mucous mem-
brane of the throat, extending to the periphe-
ral surface of the labyrinth, and forming, with
its blind end, a dilatation there, gives us the
simplest idea of a tympanum and Eustachian
tube. According to Huschke* — and his views
are more or less supported by Burdach,f
Rathke,t and Valentin,§ — the cavity of the tym-
panum with the Eustachian tube is a metamor-
phosis or remains of the first branchial fissure.
Hence, in its origin, the tympanum has nothing
in common with the labyrinth.

Valentin|| found the Eustachian tube and
cavity of the tympanum, in an embryo at the
seventh week, under the form of a conical or
pyramidal fossa. This fossa gradually extends
into a tube, at first short and wide, but after-
wards longer and narrower in proportion as the
cavity of the tympanum becomes developed,
and recedes from the cavity of the mouth.
The Eustachian tube is at first simply membra-
neous. About the middle of pregnancy, ac-
cording to Meckellf and Burdach,** the third
month according to Valentin, it acquires a
cartilaginous investment.

The blind membraneous pouch which repre-
sents the cavity of the tympanum is at first
very small and contracted, and is to be distin-
guished from the walls of the tympanum, which
it invests. The peripheral surface of the laby-
rinth forms, as is known, the inner solid wall
of the tympanum, and the tympanic ring and
membrana tympani the outer wall. In pro-
portion, therefore, as these parts, and also the
mastoid process are developed, so does the tym-
panic cavity acquire its proper form, and is
more and more withdrawn, both from the cavity
of the mouth and the lateral surface of the
head, with the integument of which it is, at an
early period, in contact.

The prolongation of the mucous membrane
of the pharynx forming the Eustachian tube
and cavity of the tympanum, is at first very
vascular, soft, and loose, like the mucous mem-
brane of the nasal and guttural cavities ; but
after birth it loses its vascularity, and assumes
a more simple character. United by loose
cellular tissue to the subjacent osseous" wall, it
applies itself over all the elevations, and dips
into the depressions of it, and moreover forms
folds in which the ossicles are enveloped. The
cavity of the tympanum is in the foetus filled
with a mucus, sometimes transparent, some-

* Isis von Oken, Jahrg. 1827, p. 401 ; Jahrg.
1828 p. 161; Jahrg. 1831, p. 951 ; and Meckel's
Archiv fur Anatomic und Physiologic, 1832, p.

t Die Physiologic als Erfahrungswissenschaft.
Bd. ii. p. 465.

J Anat. physiol. Untersuchungen uberden Kiem-
enapparat nnd das Zungenbein, 1832, p. 120.

§ Handbuch der Entwickelungsgeschichte des
Menschen, p. 211.

j| L. c. p. 211 and 212.

^ Manuel d'Anatomie, &c. torn. iii. s. 1948, p.

"Op. cit. Bd.ii. p.465.

times bloody, and varying from the consistence
of water to that of a thick jelly.

The cavity of the tympanum has been found
sometimes unusually contracted ; sometimes,
on the contrary, very much dilated. Non-de-
velopment of the Eustachian tube would be
necessarily attended by non-development of the
tympanum, but, not contrariwise. Absence
of the Eustachian tube and cavity of the tym-
panum has only been found in foetuses, in other
respects monstrous.

In describing the development of the osse-
ous labyrinth, it has been already mentioned
that its peripheral surface, which forms the
inner solid wall of the tympanum, begins to
be ossified towards the end of the third month.
An ossific point first appears on the promontory
at the circumference of the cochlear fenestra, and.
gradually extends upwards, downwards, for-
wards and backwards. At this time there
is no trace of mastoid process. In the fourth
month the sinuositas mastoidea begins to ap-
pear, and the cavity of the tympanum be-
comes somewhat wider. The aqueduct of Fal-
lopius is not yet ossified, nor the canals for the
muscles of the stapes and malleus, a state of
parts found permanent in most of the lower mam-
mifera, and also frequently met with in the irre-
gular conditions of the ear in man. When the
cochlea is arrested in its developement, the pro-
montory is small in proportion or entirely
wanting.

In the fifth month the aqueduct of Fallopius
and the canals for the muscles of the stapes and
malleus are ossified. In this month, also, the
vestibular fenestra is found completely formed,
and appears proportionally larger than in the
adult. In the sixth month, the temporal bone
being altogether more developed, and the mas-
toid process having begun to appear, the cavity
of the tympanum increases in capacity, espe-
cially its upper part, and the sinuositas mas-
toidea. The direction and situation of the
cochlear fenestra vary much at the different
periods of formation, which is owing chiefly to
the degree of development of the promontory.

The vestibular and cochlear fenestrae are
sometimes found unusually small, or even en-
tirely wanting, the latter being obliterated by
an extension of osseous substance, the former
by the same cause, or by anchylosis of the
base of the stapes. The cochlear fenestra some-
times appears to open into the vestibule, but this
is when the cochlea is in a very rudimentary
state. Such a condition may be compared with
the state of parts found in the bird's ear.

Little or nothing is known of the origin and
development of the membrana tympani. It
may be looked upon as the persistence of that
septum which exists at an early period at
the opening of all mucous canals, and which
is produced by the meeting of the indentation
inwards of the skin with the diverticulum of
the mucous cavity of the blastoderma. The
membrana tympani is larger in proportion, and
more vascular the younger the foetus is. The
form, situation, and direction of it in the foetus
is dependent on the tympanic ringr, and is quite
different from what is found in the adult. In
regard to form, it is rounder. As to situation

560

ORGAN OF HEARING.

the osseous portion of the auditory passage
not being yet developed, the membrana tympani
is found at first closer to the surface than after-
wards; and its direction is oblique from above
downwards, and from without inwards, so that
it has a more or less horizontal position, corres-
ponding to the base of the cranium.

More is known of the origin and develop-
ment of the tympanic ring in which the mem-
brana tympani is framed. It appears later
than the membrana tympani and the ossicles.
A specimen of the tympanic ring before me,
which was removed from an embryo at about
the third month, is an incomplete ring of bone
about one-tenth of an inch in diameter. It is
about the thickness of a hair, except at its
anterior extremity, which is broad and flat like
a spatula, for the extent of about one-twelfth
of an inch. The groove for the membrana
tympani can be perceived with a magnifying
glass. From the fifth month the tympanic ring
is found more or less adherent to the rest of
the temporal bone. In the lower Mammifera
there are three parts developed from the tym-
panic ring, viz. 1, the groove for the mem-
brana tympani, 2, the bulla ossea, and 3, the
osseous part of the auditory passage. In
birds the tympanic ring is represented by the
os quudratum. In man there is no bulla ossea,
only the groove for the membrana tympani and
the osseous part of the auditory passage. The
side of the tympanic ring external to the groove
shoots out to form the osseous part of the
external auditory passage, but so slowly that
from the second to the sixth or seventh year,
the lower surface of the auditory passage is
still cartilaginous, although the outer orifice to
which the cartilaginous part of the auditory
passage is fixed is already ossified. About the
twelfth year the passage is closed in by bone,
and becomes quite complete towards manhood.
The inner surface of the ring grows a little
at the lower part, and helps, together with a
process which extends from the petrous bone,
to form the lower wall of the tympanic cavity.
It is to be remarked that this inner part of the
tympanic ring always remains distinct and is
never changed so much as the external.

Fig. 261.

The tympanic ring, and the membrana tympani framed
into it. The handle of the matteus is seen shining
through ttue membrane.

The whole outer wall of the cavity of the
tympanum has been found wanting in a mon-
strous foetus. Hyrtl, who mentions the case,
says that the cavity of the tympanum itself
was represented only by a very shallow depres-

sion in the petrous bone, in which the skin of
the auditory passage formed a cul-de-sac. The
Eustachian tube was present. Hyrtl mentions
another case in which the tympanic ring was
much smaller than usual, and in which the
membrana tympani presented in the direction
of one of its radii, a large opening as if a
piece had been cut out. The so-called hiatus
Riviniunm ought, perhaps, to be looked upon,
as Huschke observes, as a defect in original
formation. The membrana tympani has been
sometimes found congenitally too large, some-
times too small, sometimes of an elongated
form, sometimes of a triangular form. A
thickening and parchment appearance of the
membrane, or ossification of it to a greater or
less extent, if not always, appears to be more
usually an acquired malformation.

2. The small bones of the tympanum. — The
small bones are formed at a very early period.
The malleus and incus appear before the
stapes. The two former, according to Rathke
and Valentin, appear like a small wart growing
out from the posterior wall of the tympanum.
The stapes is like a growth from the outer sur-
face of the labyrinth ; it appears as a small
pyramidal wart flattened on the sides and thin,
in the middle, lying, according to Rathke, in
a small funnel-like depression, the bottom of
which is the future vestibular fenestra.

According to Weber* the ossicles are not
developed in the cavity of the mucous mem-
brane of the tympanic cavity, but in a sac
which is a continuation of the dura mater, and
comes through a fissure between the petrous
bone and the squamous portion of the tem-
poral into the tympanic cavity. This situation
of the ossicles at an early period corresponds
with that of those discovered by Weber in the
fishes already mentioned. By this mode of
development, as far as regards situation,
may be explained the dislocated state of the
ossicles so frequently found in the irregular
conditions of the ear.

According to Meckel,f the ossicles are at
the commencement of the third month pro-
portionally very large, though still cartilaginous,
and the stapes not to be distinguished from the
incus. Thus, for example, the length of the
malleus in a foetus of the fourth month amounts
to three lines, whilst the length of the body
from the vertex to the coccyx measures four
inches, hence the lenght of the malleus is to
that of the trunk as one to sixteen ; whereas
in the adult the proportion is only as one to
ninety, the malleus being four lines long, and
the distance between the vertex and the coccyx
amounting to two-and-a-half feet. At birth
the ossicles are as large as in the adult.

Ossification of the small bones commences,
according to Burdaeh,J about the twelfth week.
Rathke and Valentin agree with Meckel, that
ossification begins first and at the same time in
the malleus and incus, and only afterwards in
the stapes. In the malleus the first point of
bone appears on the head, a second at the root

* Hildebrandt's Anatomic, Band. iv. p. 39.
t Op. cit. torn. iii. p. 197. s. 1948.
$ Op. cit. Band. ii. p. 384.

ORGAN OF HEARING.

561

of the long process. In the incus the first
point of ossification occurs in the longer crus
near the body, and from this point it extends
during the fourth and fifth months, so far that
the whole is ossified with the exception of the
point of the short process. The long crus
Meckel always found completely ossified,
whilst the short crus was still cartilaginous.

The stapes is still cartilaginous when ossi-
fication has made considerable progress in the
other two bones. According to Meckel ossi-
fication does not commence at any determinate
point of the stapes ; only he never observed it
first on the head. According to Kathke there
are three particular nuclei, one for each of the
sides of the triangle which the stapes repre-
sents.

The opening between the crura of the stapes
is at first very inconsiderable, — a condition
analogous to what is found permanent in the
Cetacea, £c.

The ossicles are not un frequently irregular
in their form, size, and situation. They may
even be wanting. The stapes, as it is the last
formed, presents the most numerous and most
varied malformations ; the malleus the fewest.
The stapes has been found, by Tiedemann,
as it is at first, like a pyramid without any
opening ; again, it has been found with but a
very small opening, or presenting indeed the
crura, but the space between them filled up
by a thin plate of bone. Only one crus has
been found rising from the middle of the base
in the form of a slender pedicle of bone as in
the bird, and presenting no trace of an articular
cavity for the reception of the lenticular pro-
cess of the incus, &c.

A remarkable circumstance connected with
the early formation of the malleus is the
existence, as Meckel* first observed, of a
straight cartilaginous process, having the
shape of a very elongated cone, which ex-
tends from the anterior part of the head
of the malleus to the place where the two
halves of the lower jaw unite in front. The
cartilaginous process passes out of the cavity
of the tympanum between the petrous bone
and tympanic ring. This process, though
having much the same situation, must not be
confounded with the processus gracilis. The
former lies above the latter, and both parts are
quite distinct from each other. Moreover the
cartilaginous process never ossifies, but dis-
appears in the eighth month. Huschkef has
discovered a similar process extending be-
tween the short crus of the incus and the supe-
rior horn of the hyoid bone through the me-
dium of the styloid process.

* Op. cit. torn. iii. p. 199. s. 1948. See also

Huschke Beitrage zur Physiologic und Natur-
gescUchte, p. 48. Taf. ii. Fig. 1. Isis von Oken,

1833. Heft.'vii. p. 678. Serres, Annales des
Sciences Naturelles, 1827, p. 112. Weber, Hilde-
brandt's Anatomic, 4te. Aasgabe. Band. iv. p. 47.
Rathke, op. cit. p. 122, and Valentin, op. cit.
p. 214.

t Isis von Oken, loc. cit. and Valentin, op. et
loc. cit.

VOL. II.

The most interesting irregular formation of
the malleus is what appears to be connected
in some manner with the above described early
condition of the malleus and incus. Such
cases are related by Ilyrtl,* Heusinger,f and
Hesselbach.J

2. Of the external eur. — The external ear
soon disappears in the animal series. It is
the last part of the apparatus of hearing
which makes its appearance in the human
embryo. It is very subject to irregular deve-
lopment. It is only about the middle of the
second month that a trace of it can be ob-
served. It is at first merely a slight elevation
of the skin, broad above, narrow below. In
the middle of this elevation is a longitudinal
fissure of the same form, which is narrower
and at the same time deeper from above
downwards. The prominence soon becomes
more elevated and thinner at its posterior part,
and projects above the surface of the side
of the head, from which circumstance the
middle depression is a little exposed. At the
same time or soon after, the anterior part of
the prominence is found divided into two
halves by a transverse fissure running forwards;
the inferior half is the antitragus. and the supe-
rior the commencement of the helix. At the
same time this anterior part of the external ear
rises also, and the posterior spreads more out.
In the third month the anthelix and tragus are
developed ; the concha is not yet perfectly dis-
tinct ; it is only indicated by the middle de-
pression. In the fourth and fifth month the
hollow of the concha appears, and is completely
formed in the sixth. The lobule is the last part
which presents itself.

The cartilage begins to be formed in the
third month, but is developed slowly. To-
wards the end of pregnancy, though thicker,
harder, and firmer, it is still incomplete.

The cartilaginous portion of the auditory
passage as well as the auricle is at first pro-
portionally much smaller than afterwards. The
skin lining the auditory passage is softer and
thicker than in the adult, and is covered with
a thickly set down. In the foetus the auditory
passage is rounder, straighter, and shorter than
in the adult.

The auricles may not be formed at all, or
their development may be so arrested that they
shall be represented merely by unshapely folds
of skin with or without cartilage, or they may
deviate more or less from their usual form,
size, and situation. Imperfect formation of
the auricle is frequently accompanied by ab-
sence or closure of the auditory passage. Pro-
fessor Samuel Cooper mentions the case
of a child in which there was not the slightest
trace either of external ear or auditory passage.

* Op. et loc. cit.

f Specimen mala; conformations organorum
auditus humani rarissimum et memoratu dignis-
siinum, curn tribus tabulis aeri incisis. Jenae,
1824.

+ Beschreibung der pathologischen Praparate,
welche in der kbniglichen anatomischen Anstalt
zu Wurzburg auf bewahrt werdcn. Giessen, 1824.

2 P

562

ORGAN OF HEARING.

Sometimes, however, the auditory passage has
been found regular though the auricles were
wanting.

The auditory passage is sometimes found too
wide, sometimes too narrow, sometimes too
short. Closure of the auditory passage may
be either partial or through its whole extent.
It is more rarely the effect of disease than of
irregular primitive formation. Partial closure
may be by an extension of the skin over the
mouth of the passage. Authors mention cases
of a membraneous septum sometimes deep in
the auditory passage and before the membrana
tympani, sometimes nearer the entrance of the
passage.

In monstrous foetuses all the accessory parts
of the apparatus of hearing together have been
found wanting.

II. PARALLEL BETWEEN THE EAR AND
THE EYE.

A parallel has often been drawn betwixt the
ear and the eye. Breschet, in his memoir,
already so often cited in the course of this
article, compares the perilymph to the aqueous
humour, the endolymph to the vitreous hu-
mour, and the calcareous concretions to the
crystalline body.

The comparison which I should institute
between the component parts of the ear and
the eye is the following : —

The osseous labyrinth may be compared to
the sclerotica, and the fenestra rotunda, or coch-
lear fenestra, to the cornea.

To find a part in the eye analogous to the
vestibular fenestra, we must first consider that
the latter is a yielding part of the otherwise
solid wall of the labyrinth ; that through the
medium of it, the chain of small bones and
their muscles in the tympanum exercise on the
soft parts contained in the labyrinthic cavity,
a certain degree of tension or compression
fitted probably to accommodate in some man-
ner the ear to the perception of different
degrees of sound. In the case of the eye,
the sclerotica, which corresponds to the osseous
labyrinth, is thinner and more yielding at the
middle of its circumference, (remarkably so in
the Greenland seal). From this it has been
supposed that the action of the muscles of the
eye-ball might by their compression produce
a change of shape fitted to accommodate the
eye to distances. Hence the vestibular fenestra
and middle thin part of the sclerotica might
be compared to each other in as far as regards
the function which each performs in the eco-
nomy of its own organ. However this may be,
the vestibular fenestra of the ear and the thin
part of the sclerotica correspond to each other
as far as can be in relative position ; and if we
admit the action just mentioned of the muscles
upon the eye-ball, we have, as I shall imme-
diately show, their counterparts in the muscles
of the small bones of the tympanum.

The tympanic scala of the cochlea may be
compared to the anterior chamber of the
aqueous humour, and the vestibular scala to
the posterior chamber.

The spiral lamina, considering its vascu-
larity and richness in nerves, and its forming
a partition between two chambers containing
an aqueous humour, may, as I have already
said in a former part of this article, be con-
sidered the counterpart of the iris, and the
helicotrema that of the pupil.

The membrane lining the labyrinthic cavity
bears the same relation to the latter as the
arachnoidea oculi* does to the sclerotica. The
space filled with perilymph, between the osse-
ous and membraneous labyrinth, may be con-
sidered analogous to that between the sclerotica
and choroid. It however communicates with
the scalse of the cochlea, the parts analogous
to the chambers of the aqueous humour, be-
cause there is nothing in the ear to be com-
pared to the ciliary ligament.

Forming the membraneous labyrinth we find,

1. a delicate cellular tissue supporting the
branches of the bloodvessels, and which is
sometimes found containing black pigment ;

2. a firm transparent membraneous coat, within
which, 3. is a nervous expansion ; 4. the endo-
lymph; 5. suspended in the latter the mass of
calcareous matter. The cellule-vascular layer
containing pigment, together with the rest of
the walls of the membraneous labyrinth, may
be compared to the choroid coat of the eye,
the nervous expansion to the retina, the endo-
lymph to the vitreous humour, and the calca-
reous mass to the lens.

In the lower animals the cochlea is the first
part of the ear-bulb to disappear; in regard to
the eye-ball, the aqueous chambers to which
I have compared the scalae of the cochlea, are
in like manner the first parts which in the de-
preciation of the structure of the eye, in the
animal series, disappear, e. g. the eye of the
Cephalopodous Mollusca.

Is the cochlear nerve the same in function
with the vestibular? The vestibular nerve is
the special nerve of hearing ; but does not the
cochlear nerve perform some function in the
economy of the ear analogous to what the
ciliary nerves perform in that of the eye ?

If an example is required in which the optic
nervous filaments enter the eye separately as
do the nervous filaments of the ear-bulb, it is
to be found in the Cephalopodous Mol-
lusca.f

As in front of the eyeball there is, or rather
would be, if it was not that the eyelids are
constantly in contact with the eyeball, a space
lined by a mucous membrane, the conjunctiva,
so at the peripheral surface of the ear-bulb,
there is a space, the tympanic cavity, lined by
a mucous membrane also. Moreover, as there
is a passage into the nose from the space
bounded by the conjunctiva, so does the tym-

* See my figure and description of a horizontal
section of the human eye, in Mackenzie's Practical
Treatise on Diseases of the Eye. Second Edition.
London, 1835.

t See a paper " On the Retina of the Cuttle-
fish," in the London and Edinburgh Philosophical
Magazine for January, 1836.

ORGAN OF HEARING.

563

panic cavity communicate with the throat by
the Eustachian tube. In the tympanic cavity
there is a chain of small bones, articulated to
each other and moved by muscles, which
serves to produce some change in the state of
tension of the soft parts of the ear-bulb ; in
the conjunctival space there is nothing analo-
gous, although, without pushing the point too
far, we might compare the muscles of the eye-
ball with those of the ossicles of the tym-
panum, both being equally, in fact, outside
their respective mucous membranes. In re-
gard to the ossicles I would remark that,
according to the views of Weber,* they must
be reckoned among those which do not belong
to the skeleton, and which are of very incon-
stant occurrence. Such are the bone of the
penis in many animals, the teeth, the ring of
bony plates round the. front of the sclerotica of
the bird's eye, $c.

A part in the composition of the appendages
of the eye analogous to the membrana tym-
pani is only to be conceived by supposing the
existence of a mediate anchyloblepharon, that
is, an irregular membrane stretched between
the edges of the eyelids, uniting them toge-
ther and closing in the space lined by the con-
junctiva, which space would now communi-
cate with the exterior, only by the lachrymal
canalicules and nasal duct, in the same way
that the tympanic cavity communicates with
the exterior only by the Eustachian tube. A
congenital fissure or total absence of the mem-
brana tympani is an irregularity of structure
in the ear, which may be compared to what is
regular in the eye. A mind accustomed to
trace analogies will perceive a resemblance : —
to the external auditory passage in that short
space at the opening of the eyelids extending
from the inner edge of the tarsal margin to the
outer ; to the ceruminous glands in the Mei-
bomian follicles; and to the hairs at the en-
trance of the auditory passage in the eyelashes.
The auricle, if it is necessary to look for a part
corresponding to it, may be placed in the same
category with the eyebrows.

BIBLIOGRAPHY. — General Works on the Organ
of Hearing.

Gabriel Fallopius, Observationes Anatomies.
Coloniae, 1562, 8vo. Bartholomew Eustachius, Epis-
tola de organis auditus. In ejus Opusculis Anato-
micis. Venetiis, 1563, 4to. pp. 148-164. Volcher
Koiter, De auditus instrumento. In ejus extern,
et intern, princip. c. h. partium tabulae, &c. Nori-
bergre, 1573, fol. pp. 88-105. Hieronymus Fabri-
cius ab Aqiiapendente, Libellus de visione, voce et
auditu. Rec. in ejus Opp. a B. S. Albino editis.
Lugd. Batav. 1737, fol. Julius Casserius, De vocis
auditusque organis historia anatomies. Ferrariae,
1600, fol. Et in ejus Pentaestheseion, h. e. de
quinque sensibus liber. Francof. 1610, fol. lib. iv.
pp. 148-255. CfEcili'ts Folitts, Nova internae auris
delineatio. Venetiis, 1645. 4. Recus. in Bartho-
lini epistolis et in Halleri collect, dissert, anat.
vol. iv. p. 365. Jean Mery, Description exacte de
1'oreille ; ed. cum Lamy explic. mechan. des fonc-
tions de 1'ame. Paris, 1687, 12mo. Guichard
Joseph du Verney, Observation sur 1'organe de
1'ouie, Mem. de Paris, vol. i. p. 395. Ditto, Traite

* Hildebrandt's Anatomie, Baud. iv. p. 39.

de 1'organe de 1'ouie, contenant la structure, les
usages et les maladies de toutes les parties de
1'oreille. Paris, 1683-1718, 12mo. Leide, 1731,
8vo. Treatise on the organ of hearing. London,
1737, 8vo. G. C. Sckelhammer, De auditu liber
unus, &c. Lugd. Batav. 1684, 8vo. Rec. in Man-
geti Bibl. anat. torn. ii. A. M. Vahalva, De aure
humana tractatus, &c. Genevae, 1716, 4to. Ditto,
Opera, h. e. tractatus de aure humana editione hac
quarta accuratissime descriptus tabulisque arche-
typis exornatus, &c. Omnia recensuit, &c. Joannes
Baptista Morgagnus : tomi duo. Venetiis, 1740,
4to. R. Vieu&sens, Epistola ad Societatem Reg.
Lond. missa de organo auditus. Philosophical
Transactions, 1699, vol. xxi. p. 370. Ditto, Traite
de la structure de 1'oreille. Toulouse, 1714, 4to.
J. F. Cassebohm, Disp. anat. inaug. de aure interna.
Francof. cis Viadr. 1730, 4to. Ditto, Tractatus
quatuor anatomici de aure humana, tribus figura-
rum* tabulis illustrati. Halae Magd., 1734, 4to.
Ditto, Tractatus quintus de aure humana, cui acce-
dic tractatus sextus anatomicus de aure monstri
humani c. tribus figurarum tabulis. Halae Magd.
1735, 4to. JB. S. Albinus, De aure humana inte-
riore. In ejus Academicarum annotationum, lib.
iv. Leidae, 1758, 4to. cap. ii. p. 14-15, tab. i. ii.
Geoffroy, Dissertations sur 1'organe de 1'ouie ;
IP. de rhomme; 2o. des reptiles ; 3o. des poissons.
Amsterdam, 1778, 8vo. A. Scctrpa, Disquisitiones
anatomicae de auditu et olfactu. Ticini et Medio-
lani, 1789, fol. c. tab. aen. A. Comparetti, Obser-
vationes anatomicae de aure interna comparata, c.
tab. iii. aen. Patavii, 4to. The date, 1789, is on
the title-page, but the book did not appear until
1791. C. F. L. Wildberg, Versuch einer anato-
misch - physiologisch - pathologischen Abhandlung
iiber die Gehb'rwerkzeuge des Menschen. Mit Kup-
fern. Jena, 1795. S. T. Soemmerring, Abbildung-
en des menschlichen Hbrorgans. Frankf. a M,
1806, fol. Icones organi auditus humani. Francof.
1806, fol. J. C. Saundei-s, The anatomy of the
human ear, &c. with a treatise on the diseases of
that organ, &c. Lond. 1829. C. E. Pohl, Expo-
sitio generalis anatomica organi auditus per classes
animalium. Accedunt quinque tabulae lithogra-
phicae. Vindobonae, 1818, 4to. T. H. Weber, De
aure et auditu hominis et animalium. Lipsias,
1820. D. De BlainviUe, Traite de 1'organisatioa
des Animaux, &c. vol. i. Aestheseiologie. Paris,
1822. J. van der Hoeven, Disput. anat. phys. de
organo auditus in homine. Traj. ad Rhen. 1822,
8vo. Expose sommaire des nouvelles recherches
du Dr. Ribes sur quelques parties de 1'oreille in-
terne, in Magendie, Journal de Physiologic Experi-
mentale, vol. ii. p. 237. A. Fischer, Tractatus
anatomico-physiologicus de auditu hominis, cum.
tribus tabul. aeri incis. Mosquae, 1825, 8vo. J. C.
Tettle, De 1'oreille, essai d'anatomie et de physio-
logic precede d'un expose des lois de 1'acoustique.
Paris, 1828, 8vo. G. Breschet, Recherches ana-
tomiques et phvsioloques sur 1'organe de 1'ouie et
sur 1'audition, dans rhomme et les animaux verte-
bres, 4to. Paris, 1836. Also in Memoires de
1'Academie Royale de Medecine, torn. v. 3e fasci-
cule. Paris, 1836. C. G. Lincke, Das Gehbrorgau
in anatomischer, physiologischer und pathologisch-
anatomischer Hinsicht ; also, under the title, Hand-
buch der theoretischen und praktischen Ohrenheil-
kunde. Istr. Band. Leipzig, 1837.

Works on particular parts of the organ of hearing.

On the labyrinth. — J. G. Brendel, Progr. de au-
ditu in apice conchas. Goetting. 1747. Recus. in
Halleri Collect, diss. anat. vol. iv. p. 399. Progr.
quaedam analecta de concha auris humanae. Goet-
tingae, 1747, 4to. ; also in his Opusc. edit. Wris-
berg. Goett. 1769, 4to. vol. i. J. G. Zinn, Obser-
vationes de vasis subtilioribus oculi et cochleae auris
internae. Goettingae, 1753, 4to. D. Cotunni, De
aquaeductibus auris humanae interns anatomica dis-
sertatio. Neapoli, 1761, 8vo. Viennae, 1774, 8vo.
Recus. in Sandit'ort Thesaur. dissert, vol. i. p. 389.
P. F. Meckel, Diss. de labyrinthi auris content.!*.

2 P 2

564

HEARING.

mie, physiologie und wissenschaft-
Jahrg. 1835. Heft. ii. p. 171-189,

Argentorati, 1777, 4to. A. Monro, Three treatises
on the brain, the eye, and the ear. Edinb. 1794,
tract iii. Brugnone, Observations anatomico-phy-
siologiques sur le labyrinthe de 1'oreille. In Me-
moires de 1'Acad. Imper. des Sciences, litt. et
beaux arts de Turin, pour les ann. 1805-1808.
Sciences phys. et mathein. Turin, 1809, pp. 167-
176. W. Krimer, Chemische Untersuchungen des
Labyrinthwassers. In his Physiologische Abhand-
lungen. Leipzig, 1820, p. 256. J. G. Ilg, Einige
anatomische Beobachtungen, enthaltend eine Be-
richtigung des zeitherigen Lehre vom Baue der
Schnecke des menschlichen Gehb'rorgans, nebst
einer anatomischen Beschreibung und Abbildung
eines durch ausserordentliche Knochenwucherung
sehr merkwiirdigen Schadels. Prag. 1821, 4to.
F. Rosenthul, Ueber den Bau der Spindel in mens-
schlichen Ohr. In Meckel's deutschem Archiv. fiir
die Physiologie. B. viii. p. 74-78. Huschke, Tau-
sende von Krystallen im Gehbrorgan der Vbgel. In
Froriep's Notizen. Bd. xxxiii. 1833. No. 3. 36.
Ditto, Ueber Kalkkrystalle im Ohr und anderen
Theilen des Fisches. In the Isis of Oken. 1833.
Heft. vii. p. 675. Ditto, Berichtigung die Kalk-
krystalle im Labyrinth betreffend. In the Isis, 1834.
Heft. i. p. 107. Karl Steifensand, Untersuchungen
uber die Ampullen des Gehororgans. In Miiller's
Archiv. f. Anatomic,
liche Medicin.
and taf. ii.

On the cavity of the tympanum. — D. Santorini,
Opp. posth. tab. v. A. Scarpa, De structure fene-
strae rotundas auris et de tympano secundario ana-
tomicae observationes. Mutinae, 1772.

On the membrana tympani. — A. Q. Rivinus, Diss.
de auditus vitiis. Lipsiae, 1717, 4to. p. 28, et tab.
adj. Recus. in Halleri collect, dissert, anat. vol. iv.
p. 309. A.F.Walther, Resp. Casp. Bose, Diss.
anat. de membrana tympani. Lipsise, 1725, 4to.
F. Caldani, Osservazioni sulla membrana del tim-
pano e nuove ricerche sulla ellettricita animale,
lette nell' Academiadi Scienzedi Padova. Padova,
1794, 8vo. Everard Home, On the structure and
uses of the membrana tympani of the ear. In
Philosophical Transactions, vol. xc. p. i. 1800, p. 1 j
also, On the difference of structure and uses of the
human membrana tympani and that of the elephant.
In Philos. Trans. 1823, p. i. p. 23. Brugnone,
Observations anatomiques sur 1'origine de la mem-
brane du tympan et de celle de la caisse. In Me-
moires de 1'Acad. des Sciences litterat. et beaux
arts de Turin ; pour les ann. x et xi. Scienc. Phys.
et Math. 1 Part. Turin, an xii. pp. 1-10. Vest,
Ueber die Wittmannsche Trommelfellklappe. In
medic. Jahrbiicher des oester. Staates. B. v. Wien,
1819, p. 123-133. H. J. Shrapnell, On the form
and structure of the membrana tympani. In Lon-
don Medical Gazette, vol. x. p. 120.

On the ossicles. — P. Manfredi, Novae circa aurem
observationes. In Mangeti Bibliothec. anatom.
torn. ii. p. 454. J. A. Schmid, Diss. de periosteo
ossiculorum auditus ejusque vasculis. Lugd. Bat.
1719, 4to. H. F. Teichmeyer, Diss. sist. vindi-
cias quorundam inventorum meorum anatomicorum
a nonuullis celeberrimis anatomicis in dubium vo-
catorum, lo. de tribus ossiculis auditus majoribus,
mallco, incude et stapede •, 2o. de ossiculis auditus
minoribus, ovali, semilunari, lenticulari et triangu-
lar! -, 3o. de foramine tympani. Jenae, 1727, 4to.
Rec. in Halleri collect, diss. anat. vol. iv. p. 396.
A. Carlisle, The physiology of the stapes, &c. In
Philos. Trans. 1805, p. 193. T. W. Chevalier, On
the ligaments of the human ossicula auditus. In
the Medico-Chirurgical Transactions, vol. xiii. p.i.
1825, p. 61. H. J. Shrapnell, On the structure of
the os incus, in Lond. Med. Gaz. vol. xii. p. 171.

On the muscles of the ossicles. — Magendie, Sur les
organes, qui tendent ou relachent la membrane
du tympan et la chaine des osselets de 1'ouie dans
I'homme et les animaux mammiferes, in Journ. de
Physiol. exp. torn. i. p. 341. E. Hagenbach, Dis-
quisitiones anatomicae circa musculos auris internae
hominis et uiammalium adjectis anirnadversionibus

nonnullis de ganglio auriculari give otico, cum tab.
iv. aeri incis. Basileae, 1833, 4to. Bonnafont, Nou-
velle exposition des mouvemens de la chaine des
osselets de 1'ouie. In Journal des Sciences Medi-
cales de Montpellier. Prem. ann. torn. ii. livr. iii.
1834, p. 93, 97, and livr. v. p. 175-176.

On the Eustachian tube.- — J. Senac, Observation
sur la trompe d'Eustache. In Mem. de 1'Acad. de
Paris, 1724. Hist. p. 37, edit. 8. Hist. p. 52.
J. K'ollner, Ueber den Zweck der Eustachischen
Trompete. In Reil's Archiv. fiir d. Physiologie.
Bd. ii. Heft. 1. p. 18. J. D. Herholdt, Eine An-
mcrkung ueber die Physiologie des Gehors. Ein
Seitenstiick zur Abhandlung des Herrn Kbllner.
In Reil's Archiv. f. d. Physiologie. Bd. iii. Heft,
ii. p. 165. J, K'ollner, Priifung des Bemerkungen
ueber die Physiologie des Gehbrs von Joh. Dan.
Herholdt, in Reil's Archiv. Bd. iv. Heft. i. p. 105.
C. Bressa, Ueber den Hauptnutzen der Eustachi-
schen Rbhre. Pavia, 1808. Communicated by
Meckcl, in Reil's Archiv. Bd. viii. p. 67. A. H.
Westrumb, Ueber die Bedeutung der Eustachischen
Trompete. In Meckel's Archiv. fiir Anatomic und
Physiologie. Jahrg. 1828, p. 126-143. P. F. A.
Lieboldt, Commentatio de usu tubas Eustachianae
ex anatome tam humana quam comparata et phae-
nomenis pathologicis illustratis. Goettingas, 1829,
4to.

On the external ear .— J. D. Santorini, De aure ex-
teriore. In ejus Observat. anatom. Venetiis, 1724,
4to. cap. ii. p. 37. B. S. Albinus, De cartilagine
auriculae. V. ejus Annotat. Academ. lib. vi. Leidae,
1764, 4to. cap. vii. p. 55, tab. iv. fig. 1, 2.

On the muscles of the external ear. — J. D. Santo-
rini, Observ. anatom. cap. i. tab. i, ejusdem tabulae
xvii. posthum. ex edit. M. Girardi. Parm. 1775,
fol. tab. i. A. F. Walther, Anatome musculorum
teneriorum humani corporis repetita. Lipsiae, 1731,
4to. with the table of Santorini.

On the ear-wax. — Hayyarth, in Medical Observa-
tions and Inquiries, vol. iv. edit. 2, 1772, p. 198-
205. BerzeliuSf Lehrbuch der Thierchemie. Dres-
den, 1831, 8vo. p. 440.

On the comparative anatomy of the ear. — J. Hunter,
An account of the organ ot hearing in fishes, in
Phil. Trans, and Animal Economy. The works of
Scarpa, Comparetti, Monro, Pohl, Weber, and De
Blainville, already mentioned. G. R. Treviranus,
Ueber den inneren Bau der Schnecke des Ohrs der
Vb'gel, in Tiedemann und Trevirauus Zeitschrift
fiir Physiologie. B. i. 188-196. C. J. H. Windisch-
mann, De penitiore auris in Amphibiis structura.
Lipsiae, 1831. G. Breschet, Recherches anato-
miques et physiologiques sur 1'organe de Taudition
chez les oiseaux. Paris, 1836, in 8vo. and atlas
in fol. Ditto, Sur 1'organe de TAudition chez les
Poissons. Paris, 1837.

(T,

. Wharton Jones.)

HEARING (in Physiology,) audition ; Lat.
auditus; Fr. I' audit ion, sens de 1'ouie; Germ.
das Gehor, Gehorsinn. — Of all the senses, that
of hearing is the most valuable to man in his
social condition, for without it all interchange
of ideas through the medium of a spoken
language would be impossible. To it indeed,
as a distinguished metaphysician has remarked,
we are indirectly indebted for the use of verbal
language. By the sense of hearing men and
animals take cognizance of sounds and distin-
guish their varieties, the almost innumerable
multitude of which may well excite our admi-
ration of the sense. " Who," says the excel-
lent Derham, " who but an intelligent Being,
what less than an omnipotent and infinitely
wise God, could contrive and make such a fine
body, such a medium, so susceptible of every
impression that the sense of hearing hath occasion

HEARING.

565

for, to empower all animals to express their
sense and meaning to others; to make known
their fears, their wants, their pains and sorrows
in melancholick tones; their joys and pleasures
in more harmonious notes ; to send their minds
at great distances in a short time in loud
boations ; or to express their thoughts near at
hand with a gentle voice or in secret whispers.
And to say no more, who less than the same
most wise and indulgent Creator could form
such an economy as that of melody and musick
is; that the medium should, as I said, so
readily receive every impression of sound, and
convey the melodious vibration of every musi-
cal string, the harmonious pulses of every
animal voice, and of every musical pipe; and
the ear be as well adapted and ready to receive
all these impressions as the medium to convey
them. And lastly, that by means of the curious
lodgment and inosculation of the auditory
nerves, the orgasms of the spirits should be
allayed and perturbations of the mind in a great
measure quieted and stilled ; or to express it
in the words of the last-cited famous author
(Willis), * that musick should not only affect
the fancy with delight, but also give relief to
the grief and sadness of the heart; yea, appease
all those turbulent passions which are excited
in the breast by an immoderate ferment and
fluctuation of the blood.' "

Preliminary observations on sound.* — Sound
is the result of an impulse of any kind con-
veyed by the air to our ears. The analysis
of what takes place on the production of various
familiar sounds or noises abundantly explains
this. If the ear be applied to one extremity of
a long beam of timber and a person tap with
his finger on the other, the impulse is distinctly
perceived by the impression of sound which is
conveyed. A fine probe introduced carefully
through the meatus externus, and made to
impinge upon the membrana tympani, however
gently, will occasion the sensation of sound.
To produce the sensation, then, of sound, an im-
pulse is necessary either of some solid directly
upon the membrane of the tympanum itself, or
of the air which is always in contact with that
membrane. The body by which the sound is
produced, denominated by Professor Wheat-
stone f a phonic, occasions in the surrounding
air vibrations or oscillations, corresponding in
number and extent to those which exist in
itself; and these vibrations or oscillations being
propagated to the organ of hearing, give rise to
the sensation. This agitation of the air sur-
rounding the body from whence the sound
emanates is manifest in numerous instances ; —
the report of a cannon, the rushing of waters, the
rattling of carriages, which in the crowded tho-
roughfares of London communicate their vibra-
tions to the walls and floors of the houses and
even to the furniture. In the familiar instance

* It will be perceived that in the ensuing obser-
vations the writer has borrowed largely from Sir
John HerscheFs admirable essay on sound in the
Encyclopaedia Metropolitana. He has also to
acknowledge his obligations to the article on Acous-
tics in Pouillet's Elemens de Physique.

t Annals of Philosophy, new series, vol. vi.

of eliciting sound from a finger-glass partly full
of water by rubbing the wetted finger round its
brim, the vibrations which this friction excites
in the glass are rendered evident by the crispa-
tions produced in the water immediately in
contact with it. The vibration of the water, as
indicated by these crispations, corresponds with
that of the glass — the greater the intensity of
the sound elicited, the more considerable are
the vibrations in the glass, and consequently
the more manifest are those of the water, and
vice versa. " In musical sounds we may also
observe an agitation which is often felt commu-
nicating itself to the surrounding bodies. If,
for example, \*e stand under or near a piano-
forte when it is sounding, we feel a sensible
tremor in the floor of the apartment. If we
lay the finger or hand on the instrument or
touch any other, such as a violin when it is
sounding, or a bell, we feel the same sort of
tremor in every part of them ; and this is well
observed in the case of any glass vessel, such
as a tumbler or large cup. If we strike it so
as to make it sound, and then touch the mouth
of it with the finger, we feel a sensible tremor
in the glass ; and when this internal agitation
is stopped, as it generally is by the contact
with the finger, then the sound ceases along
with it."*

The disturbance produced in the air by a
sounding body has been from a very early
period illustrated by a reference to the waves
formed in still water by a stone falling into it.
" Voice," says Vitruvius, " is breath flowing
and made sensible to the hearing by striking
the air. It moves in infinite circumferences of
circles, as when, by throwing a stone into still
water, you produce innumerable circles of
waves, increasing from the centre and spread-
ing outwards, till the boundary of the space or
some obstacle prevents their outlines from going
further. In the same manner the voice makes
its motions in circles. But in water the circles
move breadthways upon a level plane; the
voice proceeds in breadth, and also successively
ascends in height."f That the presence of air is
necessary for the production of sound is proved
by the experiment first tried by HauksbeeJ and
repeated by Biot. A bell was made to ring in
the receiver of an air-pump, and in proportion
as the air was exhausted it was found that the
sound died away, and it again returned as the
air was re-admitted. On the other hand, the
bell sounded more strongly when the air within
the receiver was condensed, and the grealer the
condensation of the air, the louder was the
sound.

Any irregular impulse communicated to the
air produces a noise, in contradistinction to
a musical sound. This latter results from a
succession of impulses, which occur at ex-
actly equal intervals of time, and which are
exactly similar in duration and intensity.
When these impulses succeed each other with
great rapidity, the sound appears continuous,

* Encycl. Britann. art. Acoustics,
t Vitruvi'is de Arch. v. 3, quoted in Whewell's
History of the Inductive Sciences.
1 Phil. Trans. 1705.

565

HEARING.

in consequence of the duration of the impres-
sion upon the auditory nerve. The frequency
of repetition necessary for the production of a
continued sound from single impulses is,
according to Sir J. Ilerschel, probably not less
than sixteen times in a second, though the
Jimit would appear to differ in different ears.

We distinguish in musical sounds, 1, the
pitch ; 2, the intensity or loudness ; 3, the
quality. The pitch of the sound depends on
the rapidity with which the vibrations succeed
each other, and any two sounds produced by
the same number of vibrations or impulses in
the same time are said to be in unison. The
loudness or intensity depends upon the violence
and extent of the primitive impulse. The quality
is supposed by Sir J. Herschel to depend on the
greater or less abruptness of the impulses, or
generally, on the law which regulates the excui-
sions of the molecules of air originally set in
motion.

Sound may be communicated by air, aeri-
form fluids, liquids or solids, with variable
degrees of velocity. In air at the temperature
of 62Q Fahr. sound travels at the rate of 1125
feet in a second, or 1090 feet in a second in
dry air at the freezing temperature.

The velocity with which sound travels is,
however, quite independent of its intensity or
its tone; sounds of all pitches and of every
quality travel with equal speed, as is proved
by the fact that distance does not destroy the
harmony of a rapid piece of music played by
a band. If notes of a different pitch travelled
with different velocities, they would not reach
the ear in the order in which they were played.
Moreover, Biot put it to the test of direct ex-
periment ; he caused several tunes to be played
on a flute at the end of a pipe 3120 feet long,
and found that they could be distinctly heard
without the slightest derangement.

Neither is the velocity of sound affected by
an increase of density in the air. It is, how-
ever, greater in warm than in cold air in conse-
quence of the greater elasticity of the former.
In the different gases much variety has been
observed in the velocity of sound ; through car-
bonic gas the rate of the velocity is said to be
one-third slower than ordinary, but through hy-
drogen gas, which is twelve times more elastic
than common air, the speed exceeds the usual
rate three and a half times. A more striking
difference is as regards the intensity of sound
or the impression it is capable of producing on
our organs of hearing. This varies conside-
rably with the increase or diminution in the
density of the transmitting gas. By means of
a piece of clock-work, which caused a ham-
mer to strike at regular intervals, the conduct-
ing power of the gas could be estimated, the
clock-work being placed in a glass receiver filled
with the gas. It was thus that Priestley ascer-
tained that in hydrogen the sound was scarcely
louder than in vacuo; in carbonic acid and in
oxygen it was somewhat louder than in air.

Water can transmit sound, as the anatomist
would infer must be the case from the fact
that fishes are provided with distinct and highly
developed organs of hearing. Ilauksbee, An-

deron, the Abb6 Nollet, and Franklin have
abundantly proved this by their experiments.
M. Colladon, by means of a tin cylinder three
yards long and eight inches in diameter, closed
at its lower end but open to the air above,
plunged vertically in the water, was enabled to
hear the sound of a bell at a distance of about
nine miles, and from numerous observations
he concluded that the velocity of sound in
water at about 46° Fahr. was equal to 4703
feet in the second.

Solids convey sound as well as or even
better than air or liquids. Elasticity and ho-
mogeneousness are the qualities which best
adapt solids for the conveyance of sound:
hard substances, then, which are the most
elastic, conduct sound best. An interesting
experiment of Hassenfratz and Gay Lussac, in
the quarries of Paris, affords a striking contrast
of the relative conducting powers of air and
solids. A blow of a hammer against the rock
produced two sounds which separated in their
progress; that propagated through the stone
arrived almost instantly, while the sound con-
veyed by the air lagged behind. A more re-
markable experiment was that of Herhold and
Rahn, related by Chladni: — a metallic wire
600 feet long was stretched horizontally, and
at one end a plate of sonorous metal was
attached ; when the plate was slightly struck,
a person at the opposite end, holding the wire
in his teeth, heard at every blow two distinct
sounds, the first transmitted almost simulta-
neously by the metal, the other arriving later
through the air. Biot, with the assistance of
Messrs. Boulard and Malus, concluded the
velocity of sound in cast iron at the tempera-
ture 51° Fah. to be 11,090 feet in a second.

Reflexion of sound. — Sonorous undulations
in passing from one medium to another always
experience a partial reflexion, and when they
encounter a fixed obstacle, they are wholly
reflected ; and in both cases the angle of in-
cidence is, as in the reflexion of light, equal to
the angle of reflexion.

Echos are sounds reflected from some ob-
stacle which is placed in their way, as the wall
of a house, or those of an apartment, or the
surface of a rock, or the vaulted roof of a
church, &c.; and a sound thus reflected may,
by meeting another similar obstacle, be again
reflected, and thus the echo may be repeated
many times in succession, becoming, however,
fainter at each repetition till it dies away alto-
gether. The phenomena of echos illustrate
beautifully the analogy between sound and
light. Thus, the reflexion of sound from con-
cave and convex surfaces takes place exactly as
in the case of light : if a reflecting surface be
concave towards an auditor, the sounds re-
flected from its several points will converge
towards him, exactly as reflected rays of light
do; and he will receive a sound more intense
than if the surface were plane, and the more
so the nearer it approaches to a sphere con-
centric with himself; the contrary is the case
if the echoing surface be convex. If the
echo of a sound excited at one station be
required to be heard most intensely at another,

HEARING.

567

the two stations ought to be conjugate foci of
the reflecting surface, i. e. such that if the
reflecting surface were polished, rays of light
diverging from one would be made after re-
flexion to converge to the other. Hence, if a
vault be in the form of a hollow ellipsoid of
revolution, and a speaker be placed in one
focus, his words will be heard by an auditor in
the other, as if his ears were close to the other's
lips. The same will hold good if the vault be
composed of two segments of paraboloids having
a common axis, and their concavities turned
towards each other; only in this case sounds
excited in the focus of one segment will be
collected in the focus of the other after two
reflexions.

The most favourable circumstances for the
production of a distinct echo from plane sur-
faces is when the auditor is placed between two
such exactly half-way. In this situation the
sounds reverberated from both will reach him
at the same instant, and reinforce each other :
if nearer to one surface than the other, the one
will reach him sooner than the other, and the
echo will be double and confused.*

We propose to enquire the part which each
portion of the complex auditory apparatus of
man performs in the function of hearing.

I. Of the internal ear.— The fact that a
part, answering precisely to the vestibule, is to
be met with in every class of animals in whom
an auditory apparatus can be detected, affords
a strong presumption that this portion of the
labyrinth is the essential part of the organ.
Here is the seat of the principal expansion of
the auditory nerve upon the saccule and
common sinus, which floating in the perilymph
communicate, through the medium of that fluid,
with the membrane of the fenestra ovalis, and
consequently with the air contained in the tym-
panum. Any vibrations or oscillations then
excited in the membrane of the fenestra ovalis,
cannot fail to affect the perilymph to a propor-
tional extent, and through it the membranous
vestibule. In the simple ear of Crustaceans
as well as that of Cephalopods and the lowest
Cyclostomous fishes, the sonorous impressions
are conveyed directly to the vestibular cavity
through the solid material in which that cavity
is formed, or, as in some Crustaceans, through
the vibration of an external membrane.

In the higher organized fishes, too, the
labyrinth constitutes the whole of the auditory
apparatus, nor has it any kind of opening to or
communication with the external air, being
lodged in the walls or cavity of the cranium,
the sonorous impressions must be conveyed
through the solid cranial parietes; for, in truth,
there is no other mode in which they can be
conveyed, and we know that solids are even
better conductors of sound than either liquids
or aerial fluids.f

As to the function performed by the otolithes,

* Herschel, Encycl. Metrop.

t Hunter, Monro, Weber, and Treviranus, how-
ever, describe a communication with the exterior in
Rays and the Shark by two long canals ; but Scarpa,
Bell, and Blainville positively deny that these
ducts perform the office of auditory canals.

or the calcareous dust, otokonics, which are
found in the sacculus vestibuli of the ears of
Cephalopods and Fishes, no satisfactory theory
has as yet been offered by any physiologist.
Although it is now admitted that similar cal-
careous particles exist in the vestibules of all
vertebrated animals, still they are only in a
rudimental condition when compared with
those of fishes ; indeed it seems not unreason-
able to suppose that the calcareous dust or
otokonie of cartilaginous fishes (the ray ot
shark for example) is rudimental of the hard,
porcellaneous, and artfully formed otolithe of
the osseous fishes.* A sort of loose notion
seems to prevail, that the presence of this hard
body in the vestibule favours the communication
of sound, by impinging upon the expansion of
the auditory nerve. The following obser-
vations of Camper no doubt propagated this
idea, if they did not originally give rise to it :
" Pour etre convaincu," says this distinguished
physiologist, " qu'un corps plus ou moins
dur, mais flottant dans une substance gela-
tineuse recoit la plus legere commotion ou
mouvement extdrieur, on n'a qu'a remplir un
verre de gelee de corne de cerf, et y plonger
quelque corps, on sentira aux doigts le mouve-
ment de ce corps des qu'on remuera le verre,
ou qu'on lui donnera un petit choc avec un
doigt de 1'autre main. Quand on enferme dans
une petite vessie quelque corps dur, le moindre
mouvement de la vessie fait branler ce corps,
qui produit une sensation tres forte sur le doigt
qui tieut la vessie. "f

Sir A. Carlisle thinks that the nature of this
substance has reference to the habits of the
particular class of fishes in which it exists.
" Fishes," he says, " are only provided with
more simple organs of hearing, ordained to
inform them of collisions among rocks and
stones, or the rushing of water or moving
bodies in that element : and since the collisions
of stones or of water are only variable in their
magnitude or intensity, fishes are provided
with these dense ossicles to repeat the sem-
blable acute tones of similarly dense substances,
such as rocks, stones, gravel, &c." Again,
" There is an especial sac of calcareous pulp
given to skates and some other cartilaginous
fishes in the place of the dense ossicles, ap-
parently intended to respond to the movements
of sand and muddy strata on which they are
doomed to reside ; and it is remarkable that the
sturgeon has its auditory ossicles consisting
partly of hard substance and partly of calca-
reous pulp." |

Weber believes that the otolithes in fishes
supply the place of the cochlea which is want-
ing in these animals: the auditory nerves being
connected with them receive the vibrations

* So definite does the form of these otolithes
appear to be in osseous fishes, that Cuvier says
the osseous fishea may be determined by their
otolithes as well as by any other character.

t Mem. de 1'Acad. des Sciences, an. 1779, and
quoted in Scarpa De auditu et olfactu, p. 23.

$ Quoted from a Mss. Essay on sound, in the
Huntcrian Catalogue, vol. iii. p. 193. Miiller calls
the otolithe " Eine freier solidcr Schwingungen
repercutirender Kbrper."

568 riEARlNG.

direct from them, or sometimes the otolithes
are so placed with reference to the expansion
of the vestibular nerve, as to be able to com-
press it against the cranium.

But in man and those animals in whom, in
addition to a more complicated labyrinth, there
is also an external auditory passage and tym-
panum, it would appear that the sonorous
vibrations are conducted in two ways; first,
through the meatus externus and tympanum
to the vestibule and semicircular canals ; and,
secondly, through the bones of the head di-
rectly to the auditory nerve. Sounds pro-
ceeding from external bodies, as Weber ob-
serves, are conveyed in the former way ; but
the oscillations of one's own voice, although
they in part find their way by the external pas-
sage, are chiefly conducted by the cranial bones;
and, as Professor Wheatstone has remarked,
those sounds are best heard which are articu-
lated most in the mouth, and with that cavity
least open, as e, ou, te, kew. Closing both ears
by firmly pressing the hands upon them, one's
own voice is not heard less distinctly, but on
the contraiy more loud and clear than when
both ears are left open ; and if only one ear be
closed, the voice is heard more distinctly and
louder in that ear than in the open one.*

The observations and experiments of Weber
render it very probable that the cochlea is that
part of the labyrinth which is more particularly
suited to appreciate sounds communicated
through the solid case of the head, or, to use
his words, that sounds propagated through the
bones of the head are heard specially by the
cochlea, but that sounds conducted through the
external meatus are perceived by the membra-
nous vestibule and semicircular canals more
easily than by the cochlea. The following con-
siderations favour these views.

It is an admitted fact in acoustics that
sounds are most perfectly conducted by sub-
stances of uniform elasticity, and that when
propagated from air or water to a solid, or
from a solid to air or water, they are conducted
much less completely. Now, inasmuch as the
cochlea may be regarded as part and parcel of
the cranial bones, the sounds which are pro-
pagated by these bones would reach the nervous
expansion in that portion of the labyrinth by the
most direct route; whereas, to affect the re-
maining parts of the labyrinth, the sound must
be conducted from the bone through the peri-
lymph to the membranous vestibule and semi-
circular canals. Moreover, when it is con-
sidered that the cochlear nerves are disposed
in a radiated mariner in the lamina spiralis,
it will appear evident that the oscillations pro-
pagated to the petrous portion of the temporal
bone must exert a direct influence on the coch-
lear portion of the auditory nerve.

One or two experiments with the tuning-fork
show not only that the cranial bones do con-
duct, but also that sounds, inaudible or im-
perfectly audible through the meatus externus,
may be distinctly heard when the sounding

* E. H. Weber De Auditu in Aunotai. Anatom.
•t Physiolog. Lips. 1834.

body is brought into contact with a bone of the
cranium or face. When the tuning-fork is put
into vibration by striking it against any solid
body, if held near the external ear its vibrations
are heard distinctly, but let the handle be
applied to the teeth or to the superior maxilla,
and the sound appears much louder ; or if the
fork be held near the ear until the sound has
almost died away, and then its handle be ap-
plied to the superior maxilla or the teeth, the
sound seems greatly to revive and continues
for a considerable period, the handle being
kept in contact with the bone.

When the conducting stem of the sounding
tuning fork is placed on any part of the head,
if both ears be closed by being covered with
the hands, a considerable augmentation of the
sound will be observed.* If the sounding-
fork be kept in contact with the head for a
short time, both ears remaining open, and then
one ear be closed, the sound will be greatly
augmented in the closed ear, and will appear
to be heard exclusively by it. This experiment
is more striking if the stem of the tuning-fork
be applied to the mastoid process on one side :
when both ears remain open, the sound seems
to be heard chiefly by the ear in the vicinity
of which the stem is placed, but when the
opposite ear is closed, it appears as if the
sound were transferred from the open to the
closed ear; and if the ear be alternately
opened and closed, the sound will alternately
appear to be transferred from the one to the
other. Similar phenomena may be observed
if both ears are closed on the first application
of the tuning-fork. The sound is at first heard
in the adjacent ear, and either remains in it
or is transferred to the opposite one, according
as the former remains closed or is opened.
Mr. Wheatstone adds that if the meatus and
concha of one ear be filled with water, the
sound from the tuning-fork will be referred to
the cavity containing the water in the same way
as when it contained air and was closed by the
hand.

These phenomena afford obvious examples
of the communication of sound through the
bones of the head. The augmentation of the
sound in the closed ear appears to result, as
Mr. Wheatstone explains,f from the recipro-
cation of the vibrations by the air contained
within the closed cavity, and this explanation
is confirmed by the fact that when the meatus
is closed by a fibrous substance, such as wool,
no increase is obtained.

The following rationale may be offered
of what occurs when the sound from the
tuning-fork is communicated to a closed
ear, in accordance with the views of Weber
respecting the function of the cochlea. The
vibrations of the fork are propagated by the
bones of the head to the cochlea, the fluid of
which being thus thrown into vibration causes
the membrane of the fenestra rotunda to vibrate,

* These experiments were first suggested by
Professor Wheatstone.— See his experiments on
audition in the Journal of the Royal Institution
for July 1827.

t Loc. cit.

HEARING.

669

by which as well as by the vibrations of the
bones, the air in the tympanum is made to
vibrate, and that cavity being closed the sono-
rous vibrations are reflected from its walls so as
to give rise to the augmentation of the sound.

Autenrieth and Rerner believed the cochlea
to be that part of the auditory apparatus by
which we perceive what the French call the
" timbre" of sounds; that quality, namely,
which depends on the nature of the material
of which the sounding body is constituted,
as well as on its form and size, and in some
degree on the manner in which sound is
elicited from it; and they considered it the
office of the vestibule to convey to the sen-
sorium the pitch and strength of sounds. Their
opinion as to the function of the cochlea was
founded on some experiments as to the extent
to which ceitain of the lower animals were
affected by particular instruments of music :
the results obtained from these experiments,
when taken in connexion with certain dif-
ferences in the form and other characteristics
of the cochlea in those animals, led these
authors to the conclusion that " those ani-
mals alone seemed to perceive a difference
of the ' timbre' of sounds of pretty uniform
pitch and loudness, in whom the cochlea was
very long and projected considerably into the
cavity of the tympanum, and was not much
concealed by the surrounding bony substance.
Thus it appeared that a dog (the cochlea of
dogs being longer than that of cats), upon
hearing a certain note of the clarionet, set up
a howl, but seemed in no way affected at
hearing the same note from the flute or violin ;
but the cat continued undisturbed, although a
variety of instruments was sounded in her
hearing. A rabbit (in which the cochlea is
prominent) ran away at the note C elicited from
a slass tumbler or from a string, but remained
still when the same note was sounded even
more loudly by the flute/'* But it is abun-
dantly evident that these experiments do not
fairly lead to the conclusion which these phy-
siologists endeavoured to establish; for, as
Weber has remarked, it is one thing to be dis-
agreeably affected by the peculiar tone of a
given note in an instrument of music, and
another thing to distinguish the timbre of the
notes of different musical instruments. As
well might we conclude that dogs excel in the
power of distinguishing scents and savours,
because the smell and taste of spirits of wine
seem to be peculiarly disagreeable to them,
and they reject instantly, although hungry,
any food offered to them with which that has
been mixed.

It seems evident that the cochlea is an in-
dication of a very advanced condition of the
organ of hearing ; beyond this we can arrive at
no definite conclusion in the present state of

* See these experiments quoted at greater length
in Weber's paper before referred to. Autenrietb/s
paper is to be found in Reil's and Autenrieth's
Archiv. fur die Physiologic, B. ix. 1809; and
contains much valuable and highly interesting
matter relative to all the parts of the organ of
hearing in several of the Mammalia.

our knowledge, unless indeed we admit the
very general one of Weber, that it is the pri-
mary seat of those auditory impressions which
are conveyed through the vibrations of the
cranial bones. But this view, however pro-
bable, and supported by much sound reasoning,
throws no light on the object of the peculiar
form and mechanism of the cochlea. We
must not omit to notice that a portion of the
vestibule is regarded by Weber as performing
a similar function to that of the cochlea, and
on similar grounds. That portion which is
known under the name of the sacculus is so
adherent to the bony wall of the vestibule,
corresponding toihejoveahemispherica, accord-
ing to Scarpa, that it cannot be separated
without laceration, and consequently it seems to
be better adapted to receive the sonorous vibra-
tions which are conveyed by the cranial bones.

The remaining parts of the labyrinth, namely,
the three semicircular canals and the common
sinus, are most affected by those sounds which
are conveyed through the external meatus : it
seems evident at least that they must be more
affected than the cochlea from the connexion
between the membrana tympani and fenestra
ovalis through the chain of tympanic ossi-
cles, by which that membrane is brought
into direct communication with the perilymph
surrounding the membranous labyrinth. On
the other hand these parts are badly adapted
to receive the impression of vibrations direct
from the cranial bones, being separated from
the corresponding osseous parts by the peri
lymph, and that part of the auditory nerve
which is distributed to them, having no con-
nexion with the bone. An experiment of
Weber illustrates the relation of the perilymph
to the membranous labyrinth, and shows that
an impulse upon the membrana tympani is
capable of affecting it. In some birds, the
falcon for example, the semicircular canals are
so large, that the membranous canals may be
easily seen. If in such a bird one osseous
semicircular canal be opened by a small open-
ing, care being taken not to injure the mem-
branous canal, and then we press the mem-
brane of the tympanum inwards, at each com
pression we observe the water contained in the
bony canal to flow out with a jerk. He there-
fore concludes that the sonorous undulations
conveyed by the cranial bones are communi-
cated more immediately to the nerve of the
cochlea, but those conveyed by the external
meatus to the nerve of the vestibule.

The semicircular canals are remarkable for
the constancy of their number, and of their re-
lative position with respect to each other, in all
animals in whom they are found. They exist
in almost all fishes, and in all the other vertebrate
classes, and in these they are never less than
three in number, two of which are always
placed vertically and one horizontally. The
opinion that the arrangement of these canals
has reference to conveying the sensation of the
direction of sounds, I find expressed by Au-
tenrieth and Kerner in the paper already re-
ferred to. "In no animal," they say, " are these
canals ever more or fewer on each side than

570

HEARING.

three, which are so situated that they correspond
to the three dimensions of a cube, its length,
breadth, and depth, and that every sound ar-
riving in one of these three directions will
always strike one canal at right angles to its
axis, and another in its length. The position
of these canals is likewise such, that the cor-
responding canals of opposite sides cannot be
parallel, and that therefore any sound which
strikes the head in any given direction affects
the semicircular canal of one side much more
than the corresponding one of the opposite
side, whereby it may be determined whether
the sound coming in a straight line (from west
to east for example,) has really moved from
west to east, or from east to west."* They
state that in animals in whom the semicircular
canals are highly developed, the power of dis-
tinguishing the direction of sounds is marked
to a proportionate degree. Thus in the mole,
the development of these canals is very con-
siderable, and from a simple experiment it
appears that this animal readily distinguishes
the direction of sounds. A mole was intro-
duced into a wide but flat vessel filled with
earth, in which he was allowed to burrow,
and it was found that the mole could be made
to move about by sounding an instrument out-
side the vessel ; if the instrument were sounded
on one side, the animal would always imme-
diately turn to the other.f The fox seemed to
distinguish the direction of sounds better than
cats : if at the same time, and at opposite sides,
the high tones of a little bell and the deep
tones of a bass viol were sounded, the fox
always turned to the side whence the high
notes came. Cats seem to be sensible of the
direction of high notes only. When upon a
violin, or a flageolet, or upon a glass goblet
containing water, high notes were sounded,
the cats always turned towards the place
whence the sound came, even although the in-
strument was concealed from them : on the
other hand, when a person seated on the ground
sounded the low notes of a bass viol before several
cats in a garden, they seemed to seek in all direc-
tions for the place of the sounding body, without
nitting upon the right one. The cow, the
horse, the pig, and the rabbit seemed to mani-
fest particularly little sensibility to the direction
of sounds. The dog appears to have less power
to distinguish the direction of sound than man;
his smell seems to assist him, and it is well
known that when a dog is called by his master,
he commonly runs backwards and forwards
for some time before he finds out the right
direction. The human semicircular canals
greatly exceed in width all others examined by
Autenrieth and Kerner, but this excess is more
as regards the canals properly so called, but
does not apply to the ampullae. Scarpa had

* Op. cit. p. 363.

t This experiment, however, was repeated by
Esser, who assures us that the direction of the
movements of the mole was not influenced by the
direction of the tones of the instrument. Kastner's
Archiv. fur die gesammte Naturlchre, B. 12, s. 56.
quoted in Treviranus, Erschcin. und Geseue des
Organisclien Lcbens.

already remarked, that although the canals of
oxen and horses were narrower than those of
man, the ampullae were scarcely at all smaller
than in the human subject. These observers
further remarked, in many animals they ex-
amined, an inverse ratio between the width
of the ampulla and that of the canals ; that
the former were wider in proportion as the
latter were narrow. In fine, they conclude
that the wider the semicircular canals, the size
of the animal being taken into account, the
greater is the power of distinguishing the direc-
tion of sound. Of the lower animals, the
first in order as regards this power is the
hedge-hog, which, after the human subject,
has, relatively to its size, the widest semicircu-
lar canals ; we may form some idea of the
width of these canals from the fact that in
their centre they are nearly as wide as the
semicircular canals of the pig, which is so
very much larger an animal. Next to the
hedge-hog stands the mole, whose canals are,
proportionally to the size of the animal, both
remarkably wide and long ; they are peculiar
also as projecting free (visible without any prepa-
tion) into the cavity of the cranium. The
mouse and the bat come next, then the fox and
the dog,* the rabbit, the cat, the pig, the cow,
the horse, and lastly the sheep.

Professor Wheatstone advocates the theory
that our notions of audible direction depend
upon the excitation of those portions of the
auditory nerve which belong to the semi-
circular canals. He conceives that we dis-
tinguish best the direction of those sounds
which are sufficiently intense to affect the bones
of the head, and that it is from the portion
which is transmitted through those bones that
our perception of the direction is obtained.
Thus, we always find it difficult to tell by the
ear the position whence the feeble tones of the
CEolian harp proceed. The three semicircular
canals, then, being situated in planes at right
angles with each other, are affected by the
sound transmitted through the bones of the
head with different degrees of intensity accord-
ing to the direction in which the sound is trans-
mitted ; for instance, if the sound be trans-
mitted in the plane of any one canal, the ner-
vous matter in that canal will be more strongly
acted on than that in either of the other two ;
or if it be transmitted in the plane intermediate
between the planes of this canal and the ad-
jacent one, the relative intensity with which
those two canals will be affected will depend
upon the direction of the intermediate plane.
The direction suggested to the mind will cor-
respond with the position of the canal upon
which the strongest impression has been made.f

* The width of the canals in dogs was found to
vary in the different races. Autenrieth and Kerner,
loc. cit.

•f Dr. Young thought that the semicircular canals
seemed very capable of assisting in the estimation
of the acuteness or pitch of a sound by receiving
its impression at their opposite ends, and occa-
sioning a recurrence of similar effects at different
points of their length, according to the different
character of the sound ; while the greater or less

HEARING.

571

No conclusions can be derived from the
experiments of Flourens with respect to the
functions of the several parts of the labyrinth.
The effects of disease had already sufficiently
indicated the relative importance of the dif-
ferent parts of the ear, and even to a certain
extent of those of the labyrinth. Thus we
knew that stoppage or destruction of the ex-
ternal parts does no more than impair the sense
of hearing, and that so long as the labyrinth
remains perfect, or at least the vestibule, the
sense is not destroyed. Sound may be con-
veyed to the auditory nerve through the bones
of the head, as may be proved by the sen-
sation of sound produced by the application
of a tuning-fork in vibration to the teeth or
to some one of the cranial bones. By a parity
of reasoning, Flourens having successively de-
stroyed the several parts of the ear in pigeons,
inferred that the nervous expansion in the ves-
tibule was the part of the organ most essential
to audition : " that in strictness, it is the only
indispensable part, for all the others may be
removed; yet if this continue, audition is not
destroyed." Partial destruction of the nervous
expansion in the vestibule only partially destroys
the sense, and complete destruction of this ex-
pansion involves total deafness. The vestibule
maybe laid open without any very considerable
alteration in the sense ; but rupture of the semi-
circular canals rendered the hearing confused
and painful, and was moreover accompanied
with a quick and violent tossing of the head.*

One can scarcely imagine vivisections less
likely to lead to useful results than those
which involve the exposure of the deep-seated
internal parts of the ear, a dissection which
even on the dead subject demands no ordinary
skill ; nor can we refrain from expressing our
opinion that had M. Flourens never attempted
these experiments, physiology would have been
none the worse, and our respect for his hu-
manity would have been all the greater.

II. Of the ac ccssory parts of the organ. —
We shall consider in succession the parts which
the external ear — the tympanum, its membrane
and ossicles, and the Eustachian tube, play in
the process of audition.

The external ear may be regarded as consist-
ing of two parts, the auricle and the meatus
auditorius externus. The complete develope-
ment of the former is found only in Mammi-
ferous animals, and exists pretty generally
throughout the class ; with, however, consider-
able diversity of form, varying from an almost
flat cartilaginous lamella, scarcely at all under
the influence of its muscles, to an elongated
funnel-shaped ear-trumpet, very moveable and
completely at the command of numerous large
muscles. Man and the Quadrumana are at one
extremity of this scale ; the Solipeds, Rumi-
nants, and Cheiroptera at the other. Some,

pressure of the stapes must serve to moderate the
tension of the fluid within the vestibule, which
serves to convey the impression. The cochlea seems
to be pretty evidently a micrometer of sound. — See
Med. Lit. p. 98.

* Conditions de 1'Audition in Experiences sur le
Systeme nerveux, p. 49. Par. 1825.

however, are devoid of the auricle, as the mole,
the zemni-rat, the mole-rat, the seal, the walrus,
&c. It is said that those animals which are
remarkable for the large developement of the
auricle are almost all timid or nocturnal, and
consequently require an acute sense of hearing.
That the auricle performs the office of an
acoustic instrument to collect and reinforce the
sounds which fall upon it, cannot be doubted
in those cases in which it is large and fully
developed, as in the horse, ass, &c. Here,
indeed, we see that the animal employs it as
we might expect such an instrument would be
used ; the open part is directed towards the
quarter whence the sound comes, and continues
so directed as long as the animal appears to listen.
So far, however, from this part being mainly the
instrument for enabling the animal to judge of
the direction of sound, it appears to me that
it cannot be applied to its full use until the
direction of the sound has been in some mea-
sure determined ; until the hearing-trumpet has
been favourably placed with respect to the
quarter whence the sound emanates, its value
is not fully experienced. If we watch the
movements of the auricle of a horse, we shall
see that he uses it altogether for concentrating
sounds from particular quarters: when he moves
it about quickly, it often seems as if he were
feeling for sounds coming from certain direc-
tions, having already acquired a tolerable
notion, if I may so speak, as to what those
directions are. Treviranus,* however, thinks
that the reinforcement of the sound is not its
principal use : " to what end," he asks, " have
its various eminences and depressions been
formed, if it have no other use than this, and
why are these particularly developed in the
human ear, which can have little or no in-
fluence as an ear-trumpet in increasing the
influence of sounds?" He supposes that in
the lower animals, but especially in man, the
auricle serves more for forming a judgment
respecting the direction of sounds than for
assisting in hearing. We cannot understand in
what way the fixed auricle of man can aid for
this purpose, being almost immoveable, and in-
deed altogether so for the purposes of collect-
ing sonorous undulations from different quar-
ters; nor indeed does it appear that the opinion
in question of Treviranus is any thing more
than a mere hypothesis. A remark of Mr.
Gough, the author of a highly interesting
paper in the Manchester Memoirs " on the
method of judging by the ear of the position
of sonorous bodies," offers a strong argument
against this notion. He observes that what-
ever may be the direction of a sound in the
open air, as soon as it enters the auditory pas-
sage, it is compelled to follow the course of
that duct until it reaches the apparatus in which
the sense of hearing resides.f

The experimental researches of Savart throw
some light upon the function of this part of
the auditory apparatus.! These experiments

* Loc. cit. B. ii. p. 137.

t Manchester Memoirs, New Series, vol. v.

i Majendie's Journal de Physklogie, torn. iv.

572

HEARING.

were suggested by the result of several ob-
servations which he made upon the communi-
cation of vibrations through the air from a
vibrating body to one placed even at a great
distance from it, and susceptible of under-
going vibrations. The effect is best seen by
using a thin membrane, such as very fine paper,
carefully stretched in a horizontal position over
the mouth of a glass, or of a small delft basin :
a thin layer of sand is spread on this, and a
glass thrown into vibration by a violin bow
is held at a little distance from it; that the
paper immediately begins to vibrate is shewn
by the motions excited in the sand, the par-
ticles of which arrange themselves into figures,
which are sometimes perfectly regular, and
which form with so much rapidity that the eye
can scarcely follow " the circumstances which
accompany the transformation of the thin layer
of sand into a greater or less number of lines
of repose."

By a series of experiments to be hereafter
detailed, Savart showed that the tympanic
membrane is capable of being thrown into
vibrations by the sonorous impulses from a
vibrating body communicated to it by the in-
terposed air. How far the external ear and
auditory canal serve to increase these vibrations
of the tympanic membrane, he sought to ascer-
tain by the following experiments. He formed
a conical tube of pasteboard, with a very wide
mouth at its base, the opening at the smaller
end being closed by a thin paper stretched
over it and glued to the margins of the open-
ing. This tube is placed resting on its base,
the membrane being upwards and per-
fectly horizontal, so that a layer of sand may
be spread over it. When a vibrating glass is
brought near and parallel to the upper surface
of this membrane, it immediately begins to
vibrate, and the grains of sand are tossed about
but raised but very slightly from the surface.
If, however, the vibrating glass be placed near
the base or the wide and open extremity of the
tube, the vibrations of the membrane will be
found to be much more manifest, and the ex-
cursions of the grains of sand so considerable,
that they are often raised to a height of three
or four centimetres ; so that there is a manifest
difference in the influence produced upon the
membrane by the sonorous undulations excited
in the air according as they impinge upon the
external surface of the membrane or upon that
which is turned towards the interior of the tube.
This phenomenon, Savart adds, may depend
upon two causes, namely, upon the concen-
tration of the sonorous undulations by the tube,
or upon the communication of motion to the
parietes of the tube, which again would com-
municate it to the membrane. With a view
to ascertain which of these causes was the
effective one, a second conical tube, open at
both ends, was held with its narrow extremity
a little above and corresponding to the narrow
extremity of the former one, but so that there
was no contact between them. If now the
glass is made to vibrate successively at the
large orifices of the two tubes, it will be found
that when placed at the orifice of the tube to

which the membrane is attached, the oscil-
lations of that membrane are considerably
greater than when the aerial undulations reach
it through the other tube. Whence it may be
inferred that in all probability the external ear
and auditory canal have, besides any influence
they may exert in modifying the movements
of the particles of the air, the additional function
of presenting a large surface to the aerial un-
dulations, consequently to enter into vibration
under their influence, and thus to contribute
to increase the excursions of the vibrating parts
of the membrane with which they are imme-
diately in contact; the auricle, by the variety
of the direction and the inclination of its sur-
faces to one another, can always present to the
air a certain number of parts, whose direction
is normal (at right angles with) to that of the
molecular movement of that fluid.

We get a general notion of the value of this
external part of the auditory apparatus in col-
lecting and directing the sonorous undulations,
from the assistance often derived in hearing
from increasing the concavity of the external
ear by placing the hand behind it, so as to
draw it forward and shorten it by pressure at
its upper and lower part; by the dulness of
hearing which it is said follows the loss of the
auricle, and from the fact, so stated, that the
seal and walrus are extremely dull of hearing.
As regards the loss of the auricle, it is said
by Kerner that this loss is followed by the
greatest dulness of hearing in those animals
in whom the osseous meatus is wanting. In a
cat, from whom the right ear was cut close to
the skull, after the wound had healed without
any stoppage of the meatus, there was a re-
markable disposition always to keep its head
turned so as to be ready to receive sounds with
the left ear, and this continued even after the
tympanic membrane of the opposite side had
been frequently perforated, that of the right side
remaining whole ; and when the left ear was
stopped (although the right tympanic mem-
brane was sound, and the only injury on that
side was the removal of the auricle,) a total deaf-
ness was manifested except to the loudest and
clearest sounds.

The tympanum and its contents. — We have
already stated that Savart had demonstrated
that the membrana tympani is thrown into
vibrations by undulations of the air excited by
a sonorous body. This he demonstrated ex-
perimentally upon the membrana tympani
itself. The temporal bone having been sepa-
rated, he sawed away the osseous meatus so
as to expose the membrane on a level with
the rest of the bone, and when it was suf-
ficiently dry, he covered it with a thin layer
of sand. A vibrating glass held parallel and
very near to the surface of the membrane
occasioned a slight movement of the grains of
sand ; but owing to the slight extent and the
shape of the membrane, it was impossible to
determine the existence of any nodal line.
In a second experiment, the cavity of the tym-
panum was opened, so as to expose the ossi-
cles of the ear and their muscles ; and it was
observed that when the internus mallei muscle

HEARING.

573

Fig. 262.

acted and rendered the membrane tense, it was
much more difficult to produce manifest move-
ments in the grains of sand ; thus affording
much reason to suppose the tensor tympani
muscle is analogous in its use to the iris, and
destined to preserve the organ from too strong
impressions. This experiment can be best tried
on the membrana tympani of the calf.

In imitation of the mechanism by which the
tension of the membrana tympani is effected,
and with a view to determine more decisively
the effects produced by variation of the tension
of that membrane, Savart constructed a conical
tube (Jig. 262), with its
apex truncated and co-
vered by a layer of very
thin paper (?/?), which
was glued to the edge of
the opening. A little
wooden lever (/ /), intro-
duced through an open-
ing in the side of the
tube, and resting on the
lower margin of this
opening (c) as a fulcrum,
was used to vary the tension of the membrane,
one of its extremities being applied to the
under surface of the membrane. It is evident
that, by depressing the extremity of the lever
that was external to the tube, the inner one
would be raised, and thus the membrane
stretched to a greater or less degree according
to the force used ; on the other hand, by ele-
vating the outer extremity, the inner one was
separated from the membrane, which was ac-
cordingly restored to its original tension. This
little lever was employed in imitation of the
handle of the malleus, which under the in-
fluence of its muscles causes the variation in
the tension of the membrana tympani. The
artificial tympanic membrane then having been
covered with a layer of sand, it was found that,
under the influence of a vibrating glass, used
as in the former experiments, a manifest dif-
ference was produced in the movements of the
grains of sand, by increasing the tension of the
paper; the greater the tension, the less the
height to which the grains of sand were raised ;
and these movements were most extensive
when the lever was withdrawn from contact,
and the membrane left to itself.

From these experiments Savart concludes
that the membrana tympani may be considered
as a body thrown into vibration by the air,
and always executing vibrations equal in num-
ber to those of the sonorous body which gave
rise to the oscillations of the air. But what is
the condition of the ossicles of the tympanum
whilst the membrane is thus in vibration? The
result of the following experiment affords a
clue to the answer of this question. To a
membrane stretched over a vessel, as in fig.
263, a piece of wood (a 6) uniform in thick-
ness is attached, so that the adherent part shall
extend from the circumference to the centre of
the membrane, while the free portion may
project beyond the circumference. When
a vibrating glass is brought near this mem-
brane, very regular figures are produced, which

Fig. 263.

however are modified by the presence of the
piece of wood, and the vibrations of the mem-
brane are communicated to the piece of wood,
on which likewise regular figures may be pro-
duced. The more extensive the membrane, the
longer and thicker may be the piece of wood
in which it can excite oscillations, and Savart
states that, with membranes of a considerable
diameter, he has produced regular vibrations
in rods of glass of large dimensions. The
oscillations of the piece of wood are much
more distinct when the adherent portion is
thinned down, as in c d, jig. 264, by which it

Fig. 264.

seems, as it were, more completely identified
with the membrane, and consequently the
oscillations of this latter are communicated di-
rectly to the thinned portion of the wood, and
thence extended to the thick portion a : sand
spread upon a will exhibit active movements,
and will produce very distinct nodal lines. Thus
it may be inferred that the malleus participates
in the oscillations of the tympanic membrane ;
and these vibrations are propagated to the incus
and stapes, and thus to the membrane of the
fenestra ovalis. The chain of ossicles then evi-
dently performs the office of a conductor of
oscillations from the membrana tympani to the
membrane of the fenestra ovalis ; but the mal-
leus likewise has the important function under
the influence of its muscles of regulating the
tension of the tympanic membrane ; and to
allow of the changes in the position of this
bone necessary for that purpose, we find it
articulated with the incus by a distinct di-
arthrodial joint, and between this latter bone
again and the stapes there exists another and
a similar joint. This mobility then of the
chain of bones, and the muscular apparatus
of the malleus and stapes are totally irrespec-
tive of the conducting office of the bones, but
have reference to the regulation of the tension
of the membrane of the tympanum as well as
of that of the fenestra ovalis.*

We have already seen how the muscle of

* The experiments of Savart above detailed have
been several times carefully repeated by me with
results precisely similar.

574

HEARING.

Fig. 265.

the malleus regulates the membrana tympani,
increases its tension, and thus limits the extent
of the excursions of its vibrations. The con-
traction of the stapedius muscle causes the
base of the stapes to compress the membrane
of the fenestra ovalis to a greater or less extent,
so that the degree of tension of that membrane
depends on the condition of this muscle.
Compression exerted upon the membrane of
the fenestra ovalis extends to the perilymph
and through it is propagated to the membrane
of the fenestra rotunda, and in this way the
same apparatus which regulates the tension of
the membrane of the fenestra ovalis performs
that office for that of the fenestra rotunda, and
Savart has devised a little apparatus which
very prettily illustrates the mariner in which
this may take place. In a disc of wood
(a bt fig. 265)
of a sufficient
thickness, he hol-
lows out two ca-
vities, o and r,
which commu-
nicate at their
bottoms with
each other by a
narrow canal (c)
hollowed in the wood, but not open on its sur-
face ; a thin membrane is extended over each
of the cavities. Thus, the air contained in
these cavities may pass easily from one to the
other, and may always maintain the same
degree of elastic tension in both. If, then,
a vibrating glass be brought near the mem-
brane r covered with a layer of sand, it will
be found to enter freely into vibration, as
evinced by the active movements of the grains
of sand. If now pressure be made with the
finger on o, r will become convex in propor-
tion as o is rendered concave by the pressure,
and when in this state, the movements of the
sand will be much less considerable than be-
fore, presenting an effect precisely similar to
that produced on the tympanic membrane by
an increase of tension. Thus, the extent of
the excursions of the vibrations of the mem-
brane r is limited by the pressure exerted upon
o, and as the membranes of the two fenestrae
are related to each other in an analogous man-
ner, we may argue that pressure upon the larger
one, that of the fenestra ovalis, will occasion
tension of the smaller, that of the fenestra
rotunda, thereby limiting the extent of the
excursions of its vibrations.

Moreover it appears, upon reference to the
anatomy of these parts, (see Jig. 252, p. 550,) that
the only muscles which have been satisfactorily
demonstrated are tensors of the tympanum ; and
that at whatever extremity of the chain of ossicles
muscular effort be first exerted, a correspond-
ing effect will be produced at the other ; that
when the stapedius muscle acts, the malleus is
thrown into a position favourable to the tension
of the membrana tympani, and, on the other
hand, the contraction of the internus mallei
depresses the stapes, and consequently in-
creases the tension of the membranes of the two
fenestrse. The cessation of muscular action

restores all three membranes to their original
laxity, nor does it appear that they admit of
any further degree of relaxation through the
influence of any vital process. The incus
forms a bond of connexion between the two
other bones, and its motions depend entirely
upon theirs in consequence of its articulation
with both, while from the fixedness of its con-
nexion with the mastoid cells, as well as its
intermediate position, and its not having any
muscles inserted into it, it is obvious that its
motions must be much more limited than those
of the other bones. Its use seems to be to
complete the chain in such a way, that by
reason of its double articulation with the mal-
leus on the one hand and the stapes on the
other, the tension of the tympanic membranes
may be regulated without any sudden or vio-
lent motion, which could scarcely be avoided
were the conductor between the membranes of
the tympanum and fenestra ovalis one piece of
bone.

But whence the necessity of at all adding
to the ear this complex apparatus of tympanum
and tympanic membrane, and why might not
the sonorous impressions have been made di-
rectly upon the membranes which close the
openings to the labyrinth ? Upon this point
Savart has offered a conjecture which seems to
afford the most probable explanation as to the
true object of these parts. If the membranes
of the fenestra, he says, had been in imme-
diate contact with the atmosphere, their elastic
state would have been constantly undergoing
changes, under the influence of the vicissitudes
of temperature of the air, a circumstance which
would, in all probability, impair the power of
the organ in detecting differences of sounds.
He presumes therefore that the membrana tym-
pani prevents this contact of the atmosphere
with the membranes of the labyrinth, and that
the cavity of the tympanum and the mastoid
cells form a kind of receptacle in which the
air, which finds its way into the tympanum
through the Eustachian tube, acquires the con-
stant temperature of the body, and establishes
in front of the openings of the labyrinth a sort
of atmosphere proper to themselves, the tem-
perature of which does not vary.

This same acute observer remarks that the
size of the membrana tympani in all proba-
bility, in the different species of animals,
exerts much influence upon the number of
sounds which they can perceive, and at the
same time upon the limits at which those
sounds begin or cease to be audible. Were
the tympanic membrane in man of greater size
than it is, there is no doubt that instead of
beginning to hear sounds which result from
about thirty vibrations in a second, we should
be able to hear only sounds of a higher pitch.
Moreover it may be reasonably presumed that
animals who have the membrana tympani
much larger than that of man, hear much
graver sounds than those which result from
thirty vibrations in a second ; and, on the other
hand, there must be other animals who hear
very acute sounds only.

Even in the human species, we observe in

HEARING.

575

different individuals a similar variation in the
limits of sensibility to sounds, that is, we find,
in the words of Dr. Wollaston, that " an ear
which would be considered as perfect with
regard to the generality of sounds, may at the
same time be completely insensible to such as
are at one or the other extremity of the scale
of musical notes, the hearing or not hearing
of which seems to depend wholly on the pitch
or frequency of vibration constituting the note,
and not upon the intensity or loudness of the
noise."* And we owe to this distinguished
man the knowledge of the interesting fact,
that an insensibility of the ear to low sounds
may be artificially induced, by exhausting the
cavity of the tympanum to a great degree.
This may be effected by forcibly attempting to
take breath by expansion of the chest, the
mouth and nose being kept shut ; after one
or two attempts, the pressure of the external
air is strongly felt upon the membrana tympani,
which is thus from the external pressure thrown
into a state of considerable tension. An ear
in this state becomes insensible to grave tones,
without losing in any degree the perception of
more acute ones. This induced defective state
of the ear, from exhaustion of the tympanum,
may even be preserved for some time without
the continued effort of inspiration and without
even stopping the breath, and may in an in-
stant be removed by the act of swallowing.
In repeating this experiment as I sit writing at
my desk, I perceive that a great degree of
stillness ensues immediately the sensation of
pressure upon the tympanic membrane is felt,
owing no doubt to the low rumbling noise of
the waggons and carriages in the street being
imperfectly audible. A similar observation
was made by Dr. Wollaston : " If I strike the
table before me with the end of my finger,"
he says, " the whole board sounds with a deep
dull note. If I strike it with my nail, there
is also at the same time a sharp sound pro-
duced by quicker vibrations of parts around
the point of contact. When the ear is ex-
hausted, it hears only the latter sound, without
perceiving in any degree the deeper note of the
whole table. In the same manner, in listening
to the sound of a carriage the deeper rumbling
noise of the body is no longer heard by an
exhausted ear; but the rattle of a chain or
screw remains at least as audible as before
exhaustion." Dr. Wollaston refers to the cu-
rious effect produced by trying this experiment
at a concert : " none of the sharper sounds are
lost, but by the suppression of a great mass of
louder sounds the shriller ones are so much
the more distinctly perceived, even to the rat-
tling of the keys of a bad instrument, or
scraping of catgut unskilfully touched." Ano-
ther very interesting circumstance connected
with this subject is the production of the same
condition of the tympanum by the sudden in-
crease of external pressure as well as by the
decrease of that within, as occurs in the diving-
bell as soon as it touches the water, the pres-

* Wollaston on Sounds inaudible by certain
Ears. Phil. Trans. 1820.

sure of which, according to Wollaston, upon
the included air closes the Eustachian tube, and
in proportion to the descent occasions a degree
of tension on the tympanum, that becomes
distressing to persons who have not learned to
obviate this inconvenience."

From one opportunity which I had of de-
scending in the diving-bell now exhibiting at the
Polytechnic Institution in Regent-street, I ex-
perienced this sensation very strongly, and
exactly as Dr. Wollaston describes it. The
first effect of the pressure on the tympanic
membrane was the production of a crackling
noise, which was immediately succeeded by a
painful sense of pressure in both ears ; but this
is immediately relieved by the act of swallow-
ing ; it soon however recurs, and may be in a
like manner again relieved. I had no means
of judging exactly as to the limits of audition ;
but I distinctly observed in conversation with
those who descended with me, that grave tones
were those least distinctly heard; the grave
tones of my own voice also were less distinct as
well as the low notes in whistling.

In such cases then it would appear that from
the strong compression exerted on the mem-
brana tympani, that membrane cannot vibrate
in unison with tones which result from a small
number of vibrations. On the other hand we
may infer, from Dr. Wollaston's observations,
that " human hearing, in general, is more con-
fined than is generally supposed with regard
to its perception of very acute sounds, and has
probably in every instance some definite limit
at no great distance beyond the sounds ordi-
narily heard." The ordinary range of human
hearing comprised between the lowest notes of
the organ and the highest known cry of insects,
includes, according to Wollaston," more than
nine octaves, the whole of which are distinctly
perceptible by most ears. Dr. Wollaston has,
however, related some cases in which the range
was much less, and limited as regards the per-
ception of high notes ; in one case, the sense
of hearing terminated at a note four octaves
above the middle E of the piano-forte; this
note he appeared to hear rather imperfectly, but
the F above it was inaudible, although his
hearing in other respects was as perfect as that
of ordinary ears ; another case was that of a
lady who could never hear the chirping of the
gryllus campestris; and in a third case the
limit was so low that the chirping of the com-
mon house-sparrow could not be heard. Dr.
Wollaston supposes that inability to hear the
piercing squeak of a bat is not very rare, as he
met with several instances of persons not aware
of such a sound.

The opinion prevailed for a long time that
rupture or destruction of the membrana tym-
pani is necessarily followed by the loss of the
sense. But Sir A. Cooper proved distinctly
that not only was hearing not destroyed, but
that in some cases of deafness it might be
punctured with considerable benefit to the
patient.* The most frequent cause of destruc-
tion of the tympanum is otitis, and provided

* Phil. Trans, for 1800 and 1801.

576

HEARING.

the suppurative process does not extend so for
as to destroy the stapes, the hearing is only
impaired; but should that bone and its attached
membrane suffer, then a total deafness is the
consequence. In one case, related by Sir A.
Cooper, the membrana tympani was entirely
destroyed on the left side, and partially so on
the right, yet this gentleman, if his attention
were excited, was capable, when in company,
of hearing whatever was said in the usual tone
of conversation, but it was remarkable that he
heard better with the left ear than with the
right, although in the former there were no
traces of a membrana tympani. He could not
hear from as great a distance as others, and he
stated that, in a voyage he had made to the
East Indies, while others, when ships were
hailed at sea, could catch words with accuracy,
his organ of hearing received only an indistinct
impression. His musical ear was not impaired,
" for he played well on the flute and had fre-
quently borne a part in a concert.'' The ex-
ternal ear too had acquired a considerable
degree of mobility under the direction of the
will, so that it could at pleasure be raised or
drawn backwards, and this motion was ob-
served to take place whenever the attention
was directed to sounds not very distinctly
audible.

The Eustachian tube evidently performs a
two-fold office : — it is the passage for the en-
trance of air into the tympanic cavity from the
throat, thus affording a provision for keeping
that cavity constantly full of air in order to
allow of the free vibration of the membranes as
well as of the chain of bones ; and it seems
obvious that the tube communicates with the
throat in order that the air introduced through
it shall have acquired the temperature of the
body. It likewise affords an outlet for the es-
cape of such sonorous undulations as do not
impinge upon the labyrinthic wall of the tym-
panum, which, were there no such communica-
tion with the external air, would cause an echo,
and in this respect it performs a function si-
milar to that of the mastoid cells. The neces-
sity of such a provision as is afforded by the
first office which the Eustachian tube performs,
is manifest from the frequency of deafness re-
sulting from a stoppage either in the tube or at
its extremity. Bressa supposed that the Eus-
tachian tube conducted the sonorous impulses
excited by one's own voice from the cavity of
the mouth to the labyrinth ;* but the incor-

* Reil and Autenrieth, Archiv.fur die Physiolo-
gic, B. viii. This was a modification of an opinion
expressed by Boerhaave, viz., that those sounds
from without which entered the mouth were conveyed
to the labyrinth through the Eustachian tube. An
English physiologist advocates the opinion that
some sounds are conveyed through the Eustachian
tube, and particularly as he supposes in the Cetacea,
from the great development of that tube in these
animals compared with the external auditory pas-
sage, and the erroneous notion propagated by Home
that the malleus had no connexion with the tym-
panum, but now disproved by the careful exami-
nation of Professor Owen. See Fletcher's Phy-
siology, and Owen's Edition of Hunter's Animal
Economy.

rectness of this notion is abundantly proved by
the fact that persons who labour under obstruc-
tion of this tube can hear their own voices
plainly enough, while they are deaf to those of
others. Moreover, if we introduce into the
mouth a watch or a vibrating tuning fork, care
being taken that they do not touch any of the
walls of the mouth, they are heard gradually
less distinctly as they are approximated to the
Eustachian tube ; indeed when held far back
in the mouth they are totally inaudible. In
some birds the air of the tympanum finds its
way not only into the mastoid cells, but also
between the two tables of the skull, as in the
owl and in singing birds. The arrangement of
the osseous structure corresponding to the
diploc is exceedingly beautiful in the canary, in
which I have examined it. The two tables
seem as it were connected by very fine and nu-
merous bony pillars, the extremities of which
are attached to each table ; cells freely commu-
nicating with each other surround these pillars
every where, and the air from the tympanum
thus traverses the whole of this cellular struc-
ture. The superfluous sonorous undulations
find their way into these cells, and being re-
peatedly reflected from their parietes become
greatly weakened, so that they can exert no fur-
ther influence upon the hearing.

Functions of the nerves. — The nervous ap-
paratus connected with the organ of hearing
consists of the nerve which receives the sono-
rous impressions, and of other nerves which are
connected with the mechanism of the organ.
That the portio mollis of the seventh pair an-
swers to the former office, anatomy alone abund-
antly proves. With respect to the latter nerves
some few remarks seem necessary. The mus-
cular apparatus of the tympanic ossicles receives
its nerves partly from the facial and partly from
the otic ganglion, thus exhibiting an analogous
arrangement to that of the muscular structure
of the iris. Such an analogy renders it ex-
tremely probable that the actions of the muscles
of the ossicles are excited in a similar way to
that in which the iris is prompted to act. The
stimulus of sound conveyed to that portion of
the nervous centre with which it is connected,
excites by reflection the motor power of the
facial nerve, which, through its connexion di-
rect or indirect with the muscles of the ossicles,
causes them to act, and the action is in propor-
tion to the intensity of the sound, inasmuch as
the more tense the membrane of the tympanum,
the less will be the excursions of its vibrations ;
as in the iris the more intense the light, the
more contracted will the pupil be. It is im-
possible in the present state of our knowledge
to say what is the office of the chorda tympani,
or whether indeed it has any office in connexion
with hearing; but we may easily conceive that
from its connexion with the facial, an irritation
of it may excite that nerve. Equally ignorant
are we of the function of the tympanic anas-
tomosis.

I shall conclude with the following brief
summary of the present state of our knowledge
respecting the functions of the several portions
of the organ of hearing.

HEART.

577

1. The vestibule is the essential part of the
organ. It detects the presence and intensity
of sound, and especially of those sounds con-
veyed through the external ear and tympanum.

2. The cochlea, lying in immediate connec-
tion with the bone, receives those sounds which
are propagated through the bones of the head.
According to Kerner it is the medium of the
perception of the timbre or quality of sounds.*

3 . Of the function of the semicircular canals
we know nothing. That they aid in forming a
judgment of the direction of sounds is conjec-
tured by Autenrieth and Kerner, and more re-
cently by Wheatstone.

4. The tympanum and its membrane render
the internal ear independent of atmospheric
vicissitudes, and the former affords a non-reci-
procating cavity for the free vibration of the
latter, as well as of the chain of ossicles.

5. The chain of ossicles acts as a conductor
of vibrations from the membrana tympani to
the fenestra ovalis, and under the influence of
the muscles regulates the tension of the mem-
brana tympani, as well a? the membrane of the
fenestra rotunda, so as to protect the ear against
the effects of sounds of great intensity.

6. The external ear and meatus are con-
ductors of vibrations ; the former in some de-
gree collects them as a hearing-trumpet would
do, and probably assists in enabling us to judge
of the direction of sounds.f

(R. B. Todd.)

HEART (in anatomy). Gr. xea£, xagjVa;
Lat. cor; Fr. cceur ; Germ. Herz ; Ital. cuore.
The movement of nutritious juices through the
texture or textures of which an organized body
is composed, is a fundamental law in Physio-
logy. In proportion as the vital actions become
more complex and energetic, the more a rapid
and certain circulation of these fluids, which
is intimately connected with this condition,
becomes indispensable, and for this purpose
we have a pulsatory sac or sacs, called hearts,
superadded to the circulatory apparatus. Ano-
ther invariable concomitant of this energetic
manifestation of the vital phenomena is the
more perfect exposure of the nutritious fluids
to the atmospheric air, and this, combined with

* Muller, who seems to regard the cochlea as an
apparatus for distinguishing the pitch of notes,
accounts for its peculiar form thus:— He supposes
it an organ in which the separate parts of the nerve
may be exposed to excitation ; for this purpose all
the finest fibres of the nerve lie exposed to the in-
fluence of the sound-conducting medium, and that
it has assumed the spiral form in order that the
nerves may be arranged in the most convenient
manner and within the smallest space . See his Frag-
ment on the sense of hearing appended to his work,
Zur vergleichenden Physiologic des Gesichtssinnes.

t Much remains to be done to determine the true
means by which we judge of the direction of sound.
The reader who may be interested on the subject
will find some valuable observations and experi-
ments in Autenrieth and Kerner's paper already
quoted, Mr. Gough's paper in the Manchester
Memoirs, vol. v., new series, and one by Venturi
in Voigt's Magazin f. d. Neueste aus der Physik.
Mr. Wheatstone's views are very briefly stated in
Dr. Elliotson's Physiology.

VOL. II.

the dissimilar media in which different animals
live and move, necessitates very important
modifications in the number, position, and
structure of these pulsatory sacs. These hearts
were until lately supposed to be exclusively
confined to the sanguiferous vessels, but Muller
and Panizza have discovered distinct pulsating
sacs placed upon the lymphatic vessels in
several of the reptile tribe, and these may be
considered lymphatic hearts.

In the lowest organized plants, as the Fungi,
Algae, &c. and in the lower classes of animals,
as the Polypi, Actiniae, and a great part of the
intestinal worms, the nutritious fluids are trans-
mitted through their substance without any
distinct canals or tubes ; while in the higher
classes of plants, and in the Medusae, &c.
among animals, vessels are present, but these
are unprovided with any pulsatory cavities. In
the articulated animals generally, the vessels
are still without any pulsatory cavities; but to
make up for the deficiency, the dorsal vessel
itself has a distinct movement of contraction
and relaxation. Various pulsatory dilatations
are placed upon the vascular system of the
common worm (Lumbricus terrestris) ; one or
two upon the vascular system of the Holo-
thuria ; and one in the Talpa cristata, where
the dorsal vessel is reflected upon itself at the
posterior extremity of the body to become con-
tinuous with an analogous ventral vessel ; all
of which may be considered as rudimentary
hearts.

As we rise in the scale of animals, we find
that the heart consists of two distinct portions —
of a stronger and more muscular cavity called
a ventricle, and of a weaker and less muscular
cavity called an auricle. The latter not only
serves as a kind of reservoir to the former, but
also, by the contraction of its muscular fibres,
drives the blood into it. This heart is placed
within a sac or pericardium, and possesses
valves to prevent the regurgitation of the blood
from the ventricle into the auricle, and from
the aorta back again into the ventricle. This
may be considered as a perfect single heart.
This single heart in some of the Mollusca and
in Fishes which have a double circulation,
propels the blood not only through the lungs,
but also through the body. In the Batrachian
Reptiles, as in the Frog, though the circulation
is single, the heart becomes more complicated ;
for instead of a single auricle we have two, one
of which receives the blood returning from the
respiratory apparatus, the other receives the
venous blood of the body. The pulmonic and
systemic circulations are here separated as far
as the auricles are concerned ; but a single
ventricle in which the venous and arterialized
blood are intermixed, still continues to propel
the sanguineous current both through the lungs
and through the body. In the Ophidia or ser-
pent tribe the heart possesses the same number
of cavities as in the Batrachian Reptiles ; but
we have a still nearer approach to the double
circulation in the presence of a rudimentary
septum ventriculorum. In some of the Sauria,
as the Crocodile, the ventricle is divided by
partitions into distinct chambers, which never-

2 Q

578

HEART.

theless communicate freely with each other. It
would appear, however, from MeckePs descrip-
tion, that the ventricle is divided by a complete
septum into two separate and distinct chambers
in the Crocodilus Lucius. In the Mammalia
and Birds, where no intermixture of the venous
and arterialized blood takes place, but where
all the blood sent along the aorta has been pre-
viously subjected freely to the influence of the
atmospheric air, we find two distinct hearts,
which in the adult have no communication
with each other; one the respiratory heart for
the transmission of the blood through the lungs,
the other the systemic heart for the transmission
of the arterialized blood through all the textures
of the body. These are not placed separate
from each other, as in some of the Mollusca,
which with a double circulation have an aquatic
respiration, but are in juxta- position, and in
fact many of the muscular fibres are common
to both.

HUMAN HEART (normal anatomy).
Position. — The heart in the human species
is lodged within the cavity of the thorax, occu-
pies the middle mediastinum, and is enclosed
in a fibro-serous capsule called pericardium.
It is placed obliquely from above downwards
and from behind forwards, in front of the spine
and behind the sternum. The apex is directed
downwards, forwards, and to the left side, pro-
jects into the notch on the anterior margin of
the left lung, and in the quiescent state of the
organ corresponds to the posterior surface of
the cartilage of the sixth rib. The base looks
upwards, backwards, and to the right side ; is
separated from the anterior part of ihe spine by
the pericardium, oesophagus, aorta, and other
parts which lie in the posterior mediastinum ;
and extends from about the fourth to the eighth
dorsal vertebra. Its right margin rests upon
the upper surface of the cordiform tendon of
the diaphragm, by which it is separated from
the stomach and liver; its left margin, which
is more vertical, looks upwards and to the left
side, and occupies an excavation on the inner
surface of the left lung. Its posterior or flat
surface rests partly upon the cordiform tendon
of the diaphragm, having the pericardium inter-
posed between them, and partly upon the inner
concave surface of the left lung.* Its position
corresponds to the union of the superior third of
the body with the two inferior thirds. The lungs
overlap the lateral, and part (rarely the whole)
of the anterior portion of the heart, leaving
only in general about an inch and a half or
two square inches of the anterior surface of the
right ventricle uncovered by the lung. It is of
importance to remember this fact in percussing
this region. The two sacs of the pleura, as
they pass between the spine and sternum to
form the mediastina, are interposed between
the lungs and the heart. The heart is subject
to slight change of position from the influence
of the contiguous organs. It is carried a little
downwards during violent contraction of the

* In 4he lower animals its position is vertical,
occupying the mesial line of the body.

diaphragm, and is pressed upwards when the
abdominal viscera are strongly compressed by
the powerful contraction of the abdominal
muscles. During expiration it has been seen
to recede deeper into the thorax, and during
inspiration again to come forward. When the
body is bent to the right side, the apex recedes
from the inner side of the left wall of the
thorax ; when bent to the left side, it is still
more closely approximated to it.

Form and external surface. — Its form is that
of a flattened cone, and it is neither symme-
trical as regards the mesial line of the body,
nor (as we shall afterwards find) is the organ
itself symmetrical. It 'presents an anterior and
a posterior surface; a right inferior or acute
margin; a left superior or obtuse margin; a
base, and an apex. Its anterior surface, which
is also turned towards the left side, is convex
and considerably longer than the posterior and
right, which is flattened. On the anterior sur-
face of the heart we find a distinct groove,
running nearly in the axis of the organ, passing
from above downwards and from right to left,
and containing the left coronary artery. A
larger portion of the heart appears to lie to the
right than to the left of this groove. There is
a similar groove on the posterior surface, which
is nearly vertical, shorter than the anterior, and
contains a branch of the right coronary artery.
These two grooves are connected with each
other at or near the apex generally by a small
notch, which is sometimes of sufficient depth
to give the heart a bifid appearance.* These
grooves mark the division of the heart into
right and left sides. These terms are, how-
ever, more applicable when describing the
organ in the lower animals ; for in the human
species the right side is also anterior and infe-
rior, and the left side posterior and superior.
Near the base of the heart and at the com-
mencement of the longitudinal grooves, we find
a circular groove deeper anteriorly than poste-
riorly, whfch contains in its posterior part the
coronary vein and branches of the coronary
arteries. This circular groove points out the
division between the auricular and ventricular
portions of the heart. Two large arteries are
placed in front of the anterior part of this
groove, the one posterior to the other. That
nearest to the groove is the aorta, which springs
from the base of the left ventricle ; the one
placed anterior is the pulmonary artery, which
arises from the upper part of the right ventricle,
and at its origin covers, along with that part of
the ventricle to which it is attached, the com-
mencement of the aorta. The ventricles form
the principal part of the heart, and occupy the
middle and apex, while the auricles are placed
at the base. The base of the ventricles is con-
nected to the base of the auricles. Two large
veins, the superior and inferior venae cavao,

* This notch in the human heart looks like the
rudiments of the fissure which in the Dugong and
Rytina separates the two ventricles from each other
nearly up to the base. This bifid form of the heart,
which is merely a temporary condition in the hu-
man species, is permanent in the Dugong and Ry-
tina. Scejifj. 264, vol. i. p. 576.

HEART.

379

enter the right, and the four pulmonary veil
m>s into the left auricle. The apex of tl

veins

apex of the
heart is in general formed by the left ventricle
alone. The base of the ventricles is cut ob-
liquely from before backwards and from above
downwards, and this explains how the anterior
surface of the ventricles should be longer than
the posterior. I have found the difference of
length between the two surfaces in a consi-
derable number of uninjected hearts to vary
from half an inch, or rather less, to an inch.
There is little difference between the length of
the two ventricles in the uninjected heart. In
the injected heart the anterior wall not only
becomes elongated but much more convex,
while the posterior wall is simply elongated,
so that the difference in length between the
anterior and posterior surfaces becomes in-
creased. This change is more marked in the
right ventricle than in the left. Cruveilhier
slates that he found the anterior surface of the
left ventricle to exceed the posterior by nine or
ten lines, and the anterior surface of the right
to exceed the posterior by fifteen lines. These
measurements have evidently been taken from
injected hearts. On the surface of the heart,
but more particularly upon the anterior surface
of the right ventricle, a white spot, varying in
size, is frequently observed. According to
Baillie it is placed on the free or inner surface
of the external serous membrane.* These spots
are so common an appearance that it is some-
what difficult to believe that they are morbid.
It is, however, very probable that they are the
result of some inflammatory action.

Except in very emaciated subjects there is a
greater or less quantity of fat occupying the
auricular and ventricular grooves. This fat is
generally in greater abundance in old subjects
than in young, in accordance with the general
law, that the adipose tissue in young persons
is principally collected on the surface, and in
old persons around the internal organs. When
in greater quantity, it is deposited along the
ramifications of the coronary vessels, and may,
in cases of great obesity, almost completely
envelope the surface of the heart. It is gene-
rally placed in greater quantities on the right
side than on the left.

The human heart may be considered as con-
sisting of two distinct hearts separated from
each other by a fleshy septum, and which in
the adult have in general no communication.
The position of the fleshy septum separating
the ventricles is marked by the ventricular
grooves. Each heart consists of an auricle and
ventricle which communicate by a large orifice.
The right heart is occasionally termed the pul-
monic heart, from its circulating the blood
through the lungs ; and as it circulates the
dark blood it was termed the cceur a sang noir
by Bichat. The left is occasionally called sys-
temic hearty as it circulates the blood through

* In three hearts in which I carefully examined
these white patches, I could distinctly trace the
serous membrane over them. See the observations
of M. Bizot (Memoires de la Societe Medicale
d'Observation de Paris, torn. i. p. 347, 1836,) on
these spots.

the body generally, and is the caur a sang rouge
of Bichat. The auricles, from their immediate
connexion with the large veins of the heart,
sometimes receive the name of venous portion
of the heart (pars cordis venosa) ; and in the
same manner the term arterial portion of the
heart (pars cordis arteriosa) has been applied
to the ventricles from their connexion with the
large arteries. In describing the different ca-
vities of the heart we shall take them in the
order in which the blood passes through them.

Right auricle (auricula dextra vel infer iort
atrium venarum cava rum). External surface.
— To see the external form of the auricles pro-
perly it is necessary that they be first filled
with injection. The right auricle is of an irre-
gular figure, having some resemblance to a
cube, and occupies the anterior, right, and in-
ferior part of the base of the heart. It receives
all the systemic venous blood of the body.
Its inferior portion rests upon the diaphragm.
Its largest diameter runs in a direction from
behind forward, and from right to left. It is
broadest posteriorly, becoming narrow and pro-
longed anteriorly, where it terminates in a
small and free appendix, which, from its re-
semblance to the external ear of the dog, has
been termed auricle. This appendix is gene-
rally serrated on the edges, more particularly
on the external, and projects between the aorta
and the upper and anterior margin of the right
ventricle. To this smaller portion the term
proper auricle has been given, while the larger
portion has been called sinus venosus. This
division of the auricle into proper auricle and
sinus venosus is more distinct in the left than
in the right auricle. The posterior surface of
the right auricle is connected with the entrance
of the two cavae ; its inferior with the base of
the right ventricle ; its internal with the left
auricle; its outer surface is free; and anteriorly
it is prolonged into the proper auricle. The
junction of its internal surface with the cor-
responding surface of the opposite auricle is
marked by an indistinct groove, which cor-
responds to the attachment of the septum sepa-
rating the two auricles. Its external surface is
placed on a plane internal to the outer edge of
the right ventricle.

Internal surJ'ace.^-The inner surface of the
right auricle can be satisfactorily examined only
when it is opened in situ. Its interior can be
best exposed by making a longitudinal incision
from the appendix to the orifice of the inferior
cava, then opening the superior cava along its
anterior surface and connecting the two inci-
sions. The inner aspect of the right auricle
presents four surfaces: — 1. a posterior, where
the two venae cavae enter; 2. an outer, upon
which numerous muscular bands are seen
standing in relief; 3. an internal, which is
nearly smooth, forms the septum between the
two auricles, and presents an oval depression,
about the size of the point of the finger, called
the fossa ovalis ; 4. an anterior, formed by the
appendix, and which also presents numerous
muscular bundles. The superior or descend-
ing vena cava enters at the upper and posterior
angle, the inferior or ascending cava at the
2 Q 2

580

HEART.

posterior and inferior. The entrance of the
superior cava looks downwards and forwards
in the direction of the body of the auricle ; the
entrance of the cava inferior is directed up-
wards, backwards, and inwards. These two
orifices are circular, and that of the cava infe-
rior is larger than that of the cava superior.
The right margins of these veins are continuous
with each other ; the left or anterior margins
are continuous with the auricle, which in fact
appears at first sight to be formed by an ex-
pansion of the veins ; hence the term sinus
venosus. Around the left margin of the en-
trance of the cava superior there is a prominent
band of muscular fibres; and around its right
and posterior margin there is another but less
prominent band placed at its angle of junction
with the right margin of the inferior cava. This
last band occupies the position of the sup-
posed tubercle of Lower (tuberculum Loweri).
The cava inferior occasionally forms a dilata-
tion immediately before it enters into the au-
ricle. The venae cavae have properly no valves
at their entrance into the auricles.* The fossa
ovalis ( valvula foraminis ovalis, vestigium Jb-
ra minis ovalis), which marks the position of
the foramen ovale by which the two auricles
communicated freely with each other in the
fetus, is seen at the lower and right portion of
the auricle, partly placed in a notch in the
posterior and lower part of the fleshy portion
of the septum, and partly in the upper part of
the vena cava ascendens as it passes in to form
the sinus venosus. The upper and anterior
margins of this depression are thick and pro-
jecting (annulus sen isthmus Vieusseni, columns
Jbraminis ovalis). This was supposed by Vi-
eussens to prevent the blood of the cava supe-
rior from falling into the cava inferior, an effect
which Lower also imagined might be produced
by the tubercle which he supposed was placed
at the junction of the two veins. We have
already pointed out that the orifices of the two
veins are placed in different directions, which
is sufficient to prevent the descending column
of blood falling directly upon the ascending.
The posterior and lower margins of the fossa
ovalis are ill-defined. The surface of the de-
pression is sometimes smooth, at other times
uneven and reticulated. Betwepn the upper
margin of the depression and the annulus or
thickened edge of the fossa ovalis we frequently
find a small slit passing from below upwards,
and forming a valvular opening between the
two auricles. The remains of the Eustachian
valve (foraminis ovalis anterior valvula) may
be seen running from the anterior and left side
of the entrance of the cava inferior to the left
side of the fossa ovalis, where it attaches itself
to the annulus. This valve exhibits very va-
rious appearances in the adult: sometimes it is
very indistinctly marked, at other times it is
sufficiently apparent, and much more rarely it
approaches the size which it presents in fetal
life. It is frequently reticulated. Its convex

* The Fustachian valve cannot be considered as
essentially connected with the cava inferior in the
adult.

margin is attached to the surface of the vein
and auricle ; its concave margin is free ; its su-
perior and convex surface looks towards the
auricle, and its lower and concave surface to-
wards the entrance of the vein. Placed to the
left of the Eustachian valve, and between it
and the upper and outer part of the base of the
ventricle, is the orifice of the coronary vein. A
valve (valvula Thebesii), the free and concave
margin of which is directed upwards, covers
the entrance of this vein. It is sometimes im-
perfect, occasionally reticulated. Instead of
one coronary valve we may have two or more,
one placed behind another. These two valves,
viz. the Eustachian and Thebesian, are formed
by a reduplicature of the lining serous mem-
brane of the heart.

The Eustachian valve frequently, however,
contains some muscular fibres at its fixed mar-
gin. A number of small openings (foramina
Thebesii) may be seen on the inner surface of
the auricle, some of which lead into depres-
sions ; others are the orifices of small veins.
The muscular fibres projecting from the ante-
rior and outer surface, already alluded to, pass
vertically from the auricle to the edges of the
auriculo-ventricular opening. These, from their
supposed resemblance to the teeth of a comb,
are termed musculi pectinati. Smaller bun-
dles cross among the larger, giving the inner
surface at this part a reticulated appearance.
At the places where the transverse fibres are
deficient, the outer and inner serous mem-
branes of the heart lie in close contact. In the
floor or base of the auricle there is a large oval
opening leading into the ventricle (right au-
riculo-ventricular opening), having its upper
margin surrounded by a white ring. The up-
per part of this ring has a yellowish colour
from the auricular tendinous ring being here
translucent, so that the fat lying in the auri-
cular groove is seen through it.

Right ventricle (ventriculus anterior, v. dex-
ter,v.pulmonalis.) External surf ace. — The right
ventricle occupies the anterior and inferior por-
tion of the right side of the heart. Its form is
pyramidal, the base looking towards the au-
ricle, its apex towards the apex of the heart.
Its walls are much thicker than those of the
auricle. This thickness arises from the in-
creased number of its muscular fibres.

Internal surface. — The right ventricle may
be best opened by making an incision along its
right edge from the base to the apex, and
another from the root of the pulmonary artery
along its anterior surface near the septum to
join the other at the apex. On examining the
interior, its internal and posterior walls are
seen to be common to it and the opposite
ventricle, the anterior and external walls to
belong exclusively to itself. Its posterior and
internal walls are convex, its anterior and
internal concave. Its posterior and external
walls are decidedly shorter than its internal and
anterior. Its parietes are rather thinner at their
attachment to the anterior margin of the septum
than along its posterior margin. They are also
considerably thinner at the apex than towards
the base. * A number of fleshy columns

HEART.

581

(columns earner, terete* laccrti) project from
the inner surface. We will find that they
present three different appearances in both
ventricles. 1. The more numerous are attached
to the walls of the ventricles by their two
extremities, so that we can introduce a probe
under the middle part. These divide and sub-
divide in a variety of ways. 2. Others are
attached to the walls of the ventricles by the
whole of their external surface, while their
internal surface stands in relief from these walls.
3. Others are fixed to the walls of the ventricle
by their lower extremities, are perfectly free in
the rest of their course, and terminate either
in a blunt extremity or in several short pro-
cesses. These last are few in number, nearly
vertical, and have received the name of mmculi
papil/ares. These columnae carneae form an in-
tricate network on the inner surface of the
ventricle, and some of them occasionally cross
its cavity near the apex. They are more
numerous on the anterior and external than on
the posterior and internal walls. Two large
openings are placed at the base of the ventricle.
The larger, oval in the empty, somewhat cir-
cular in the distended heart, is the right
auriculo-ventricular opening, the upper margin
of which was already seen in the right auricle.
The smaller is circular, is placed anterior and
to the left, is about three-quarters of an inch
higher than the larger, and is the orifice of the
pulmonary artery. That portion of the ven-
tricle from which the pulmonary artery springs
is prolonged upwards above the level of the
rest of the ventricle. To this prolongation
Cruveilhier has given the name of the infun-
dibulum.*

The inner surface, particularly the posterior
part of this infundibulum, is smooth and
deprived of columnae carnea-. Around the
auriculo-ventricular opening a valve is placed,
the fixed margin of which is attached to the
circumference of the opening; the free margin
projects into the ventricle. This valve, which
forms a complete ring at its attachment, termi-
nates in several apices, three of which are much
more prominent than the rest, and on this
account it receives the name of the tricuspid
or triglochin valve (valvula triglochis v. tri-
cuxpis). The anterior of these three portions,
which is placed on the side nearest to the orifice
of the pulmonary artery, is more prominent and
broader than the posterior and internal portions,
and is separated from them by deeper notches
than these two are from each other. From this
circumstance some are inclined to consider this
valve as consisting of two portions only. It
contains several small tubercles at its free margin.

* This part is very minutely described by Wolff
under the term conns arteriosus. Under the term
infundibulwn Wolff included a larger portion oi the
ventricle, apparently that portion placed above a
line drawn from the upper and right margin of the
ventricle obliquely downwards to the anterior fissure.
As the upper part of the right ventricle becomes
gradually narrower, he supposed that it increases
the velocity and impetus of the blood as it is driven
from the ventricle. — Acta Acad. Imper. Pctropol.
pro anno 1780, torn. vi. p. 209. 1784.

This valve, like the other valves at the arterial
and left auricular orifices, to be afterwards
described, is composed of areduplicatureof the
lining membrane containing some tendinous
fibres between them. It is translucent and of
great toughness. A number of tendinous cords
(chorda tendinea) pass between the apices of
these valves and the inner surface of the ven-
tricle. Though the arrangement of these chorda?
tendineae is not uniform in all cases, yet it is
of importance to remark, as prominently bearing
upon the discussions connected with the man-
ner in which these valves at the auriculo-ven-
tricular opening perform their office, that their
general distribution is the same, and evidently
intended for a specific purpose.* The greater
part of these chordae tendineae spring from the
free and blunt extremities of the third kind of
columnae carneae (musculi pupillares) which
we have described ; some from the other two
kinds, and others again from the smooth portion
of the septum, and more particularly from the
lower part of the smooth surface which leads
into the infundibulum. These tendinous cords
diverge to reach their insertion, some of them
dividing and subdividing two or three times,
occasionally crossing each other, and are
inserted principally into the apices and margins
of the notches which separate the valve into its
three portions. A few of these cords pass
between the columns and inner surface of the
ventricle without being attached to the valve.
The internal lip of the valve has its lower
margin tied more closely down to the surface
of the ventricle by these cords than the other
two lips ; besides several short cords frequently
pass between the internal surface of the ven-
tricle and the ventricular surface of that portion
of the valve. At the exit of the pulmonary
artery from the upper, anterior, and left part of
the ventricle, three valves are placed (fig. 268).
These from their form have received the name
of semilunar or sigmoid valves. Their fixed
margins are convex,and adhere to the tendinous
ring to which the origin of the artery is attached ;
their free edges, from the presence of a small
triangular tubercle in the middle of each (cor-
pus Arantii, corpusculum Morgagni, corpus
sesamoideum,) form two slight semilunar curves
(7?g.268). The extremities of the curved attached
edges look in the course of the artery. When
the blood rushes from the ventricle into the
pulmonary artery, the valves are laid against
the sides of the vessel, and the free edge becomes
vertical ; when, on the other hand, a portion of
the blood falls back towards the ventricle, the
valves are thrown inwards and completely
occupy the calibre of the artery. At this time
the concave surfaces of the valves are directed
in the course of the artery, the convex surfaces
towards the ventricle. These valves may be
distinguished by the terms anterior, posterior or
left, and superior or right. The suggestion of

* Mr. T. W. King states (Guy's Hospital Reports,
no. iv. p. 123.) that there is a disposition in the
chord* tendinese from each fleshy column to attach
themselves to the adjoining edges of two lips of th«
valve, as in the left ventricle.

582

HEART.

Fantonus, that as three circular valves meeting
in the axis of a canal would leave a small space
in the axis itself, so the use of these corpora
Arantii may be to fill up the interval which
would thus otherwise be left, has generally
been adopted.* These valves are thin and
transparent, yet of considerable strength. Their
attached are thicker than their free margins.
That portion of the pulmonary artery which is
placed immediately above the attachment of the
semilunar valves bulges out and forms three
projections, named from their discoverer
sinuses of Valsalva. These sinuses are more
apparent in old than in young persons.

Left auricle (auricula sinistra ; a. pos-
terior ; atrium sen sinus venarum pulmonalium,
a. aorticum). External surface. — It occupies
the upper, posterior, and left part of the base of
the heart, arid receives the blood brought back
from the lungs by the pulmonary veins. The
only part of the left auricle that can be fairly
seen after the pericardium has been opened,
and none of the parts disturbed, is the appendix.
To see it properly the pulmonary artery and
aorta must be cut through and thrown forwards.
It is of a very irregular shape, some anatomists
comparing it to an oblong quadrilateral, others
to an irregular cuboidal figure. Posteriorly
it rests upon the spinal column, from which itis
separated by the parts mentioned in describing
the position of the heart itself, and appears as
if confined between the spine and base of the
heart, — a fact which has been considerably
insisted upon in some of the explanations of the
tilting motion of the heart. Superiorly and to
the right it is connected to the auricle of the
opposite side. More anteriorly and still to the
right it is free, and is separated from the right
auricle by the aorta and pulmonary artery. Its
base is connected to the base of the corres-
ponding ventricle. The auricle is prolonged
forwards at first to the left, but bends towards
the right before terminating. This prolongation
is the appendix or proper auricle. This
appendix is longer, narrower, more curved,
more denticulated on the edges, and more
capacious than the corresponding part of the
right auricle, and projects along the left side of
the pulmonary artery, a little beyond and below
the anterior margin of the left ventricle. The
two left pulmonary veins enter the posterior
and left side, and the two right pulmonary
veins enter the posterior and right side of the
auricle.

The left auricle, like the right, has been
divided into sinus venosus and proper auricle.
Inner surface. — The inner surface may be
divided into, 1st, a posterior, which is smooth,
and which belongs exclusively to itself; 2d, an

* I find that the late Dr. A. Duncan, jun. has
justly remarked that there is no necessity for calling
in the aid of the corpora Arantii to produce the
complete obstruction of the calibre of the artery, as
the free edges of these valves, when they are
thrown inwards* do not exactly lie in close apposition
but overlap each other* Besides these bodies are
occasionally very indistinct, and frequently do not
project beyond the free margin of the valves,
especially in the pulmonary semilunar valves*

anterior, which communicates by a round
opening with the cavity of the appendix ; 3d, a
right, the anterior and greater part of which
is formed by the septum of the auricles. Upon
this is observed the fossa ovalis, but without
the distinct depression which it presented in
the right auricle. The upper margin of the
valve, between which and the upper thick edge
of the fossa ovalis the oblique aperture exists,
which we formerly stated to be frequently
observed here, is often distinctly seen in the
left auricle. The valvular nature of this small
slit must prevent any intermixture of the blood
of the two sides. This margin, when present,
looks forwards and to the left. The two right
pulmonary veins open upon this surface imme-
diately posterior to the septum, and between
the septum and posterior surface. 4th, A left,
into which the two pulmonary veins of the left
side open.

The pulmonary veins of the two lungs are
thus separated from each other by the whole
breadth of the auricle. The veins of the same
side open into the auricle, the one immediately
below the other, so that they occupy the whole
height of the auricle. The superior is generally
the larger. The two veins of the same side
occasionally enter by a common opening, or
this may occur on one side only. At other
times we may have five openings. These veins,
like the cavee, have no valves at their termina-
tion in the auricle. At the lower and anterior
part of the auricle a large oval opening presents
itself. This is the left auriculo-ventricular
opening, and like that on the right side it has
its upper margin surrounded by a white tendi-*
nous ring. This ring, unlike that of the right
side, is everywhere sufficiently opaque to pre-
vent the fat placed in the auricular groove to
be seen through it.

The inner surface of the left auricle differs
materially from that of the right in its greater
smoothness, and the consequently smaller num-
ber of its musculi pectinati. In fact, the only
place in which these are observed, and that too
to a comparatively smaller extent than in the
corresponding portion of the right, is the ap-
pendix. This arises from the greater strength
of the left auricle, the muscular fibres being so
closely laid together as not to leave any interval
between them.

Left ventricle (ventriculus sinister, v.pos*
terior, v. aorticus.) External surface.- — It is
of a conical shape, and occupies the posterior
and left part of the heart. It is rounded and
does not present the flattened appearance of
the right ventricle. It projects downwards
beyond the right, and forms the apex of the
heart. Though the left proceeds lower down
than the right ventricle, that portion of the right
called infundibulum or conus arteriosus mounts
higher than any part of the left. The left is on
the whole a little longer than the right. The
circumference of the base of the right ventricle
is greater than that of the left, exceeding it in
some cases in the injected heart by about two
inches.

Internal surface. — This ventricle is best
opened by making an incision close upon the

HEART.

583

anterior fissure from the apex near to the com-
mencement of the aorta, then another in-
cision midway between the posterior fissure
and left edge of the ventricle, commencing near
the base and carrying it downwards to join the
other at the apex. The anterior and right
parietes of the internal surface are formed by
the septum ; the posterior and left belong ex-
clusively to itself. The walls of the left ven-
tricle are considerably thicker than those of the
fight, and remain apart, while those of the right
fall together. As connected with this we may
observe that the septum is concave towards the
left ventricle and convex towards the right. As
the obstacles to be overcome in transmitting the
blood through the body are greater than those
to be overcome in transmitting it through the
lungs, so is the left ventricle thicker than the
right. It is important to remark, as connected
with the pathology of spontaneous rupture of
the heart, that the walls of the left, like those
of the right ventricle, are considerably thinner
at the apex than towards the base.* The ante-
rior and right parietes are longer than the pos-
terior and left. The columnae may be arranged
into three kinds, such as we have described in
the right ventricle. They are not so numerous
in the left ventricle as in the right. The greater
number are also smaller, and are principally
placed upon the posterior and left wall, near the
apex of which they form deep areolae.f The
upper part of the septum which leads to the
aortic opening, which we shall presently describe,
is quite smooth. In the base of the ventricle
we find two openings placed closely together ;
one of these, the smaller, is placed to the right
and a little anterior, is the commencement of
the aorta, and occupies the upper and right
corner of the ventricle ; the other is larger and
placed to the left and a little posterior, and is
the auriculo-ventricular opening of this side.
The aortic opening is only separated from the
auriculo-ventricular opening by the tendinous
ring, and from the orifice of the pulmonary
artery by the upper part of the septum. A
valve resembling the tricuspid is attached to
the tendinous ring around the auriculo-ventri-
cular opening, which, from being more de-
cidedly divided into two lips, is termed bicuspid,
and from its fanciful resemblance to a bishop's
mitre has generally received the name of mitral
valve. Like the tricuspid it forms a complete
ring around the margin of the auriculo-ventri-
cular opening. The anterior lip of the valve in
the quiescent state of the heart hangs suspended
between the auriculo-ventricular opening and
the origin of the aorta, and is considerably
larger and more moveable than the posterior,
which is smaller and more limited in its move-

* The circular arrangement of the muscular
fibres around the apex (fig. 274) must have the
effect of rapidly approximating the inner surfaces
of the ventricles at the apex during their systole,
more particularly when the apex is elongated, as in
the heart of the horse, and thus prevent the pres-
sure from falling upon the extremity of the apex,
•where it is very weakly protected.

t Laennec has erroneously stated in general
terms that the columns of the right ventticlc are
larger than those of the left.

ments. The mitral valve is formed in the same
manner as the tricuspid, and is somewhat
thicker and stronger, and like it contains a
number of tubercles in its free margin. The
large anterior lip of the mitral valve projecting
downwards into the ventricle was described by
Lieutaud and by others since his time as
dividing the ventricle into two portions, an
aortic and a ventricular. These are separated
from each other at the upper part by the valve
only; at every other part they communicate
with each other. The same authors have
described the larger lip of the tricuspid valve
as effecting a similar division of the pulmonic
ventricle. Two of the columnae carneae in the
left ventricle belong to the third kind (musculi
papillares) already described, and are much
stronger than any to be found in the right ven-
tricle. They are attached to the lower part of
its cavity, pass upwards, and about the middle
of the ventricle terminate in a blunt extremity,
from which a number of chordae tendineae pass
to be attached to the margins of the mitral
valve. Bouillaud describes these two columnae
as uniformly occupying the same position, one
being placed at the junction of its left and
posterior walls to form the left margin of the
heart ; the other on the posterior wall near its
junction with the posterior margin of the sep-
tum.* Each of these fleshy columns consists
of two fasciculi, of an anterior and superior,
and of a posterior and inferior. The posterior
and inferior fasciculus is shorter and less strong
than the anterior. The chordae tendineae of
the two anterior or internal fasciculi proceed to
attach themselves to the margins of the anterior
or larger lip of the valves, those from one
fasciculus passing to one edge of the lip, and
those of the other fasciculus to the other ed^e.
As these chordae tendineae proceed from the
fasciculi to the valve, they diverge from those of
the same fasciculus, but converge towards those
of the other fasciculus. (Fig. 269 shews the
attachment of the chordae tendineae of the two
anterior or internal fasciculi.) The chordae
tendineae from the posterior fasciculi pass in a
similar manner to be attached to the posterior
lip. The posterior lip is fixed closer in its
situation than the anterior, by the chordae ten-
dineae, and this is frequently increased by some
of these cords passing from the walls of the
ventricle to be attached to the ventricular sur-
face of the valve, sometimes nearly as high as
the fixed margin of the valve. These chordae
tendineae are stronger, fewer in number, and
less subdivided than those in the right ventricle.
Several of them pass between the fleshy columns
without being attached to the valves, as in the
right ventricle. Though the description here
given is not perfectly uniform in every case, but
is liable to frequent varieties, — by the non-divi-

* I have satisfied myself by numerous examina-
tions, of the accuracy of Bouillaud's account of the
position of these musculi papillares and the arrange-
ment of the chordae tendineae in the human heart.
I have found them occupying a similar position in
the heart of the horse, ox, ass, sheep, pig, dog,
rabbit, hedge-hog, and some birds, and suspect
that this will be found a general law in all th»
warm-blooded animals.

584

HEART.

sion of the mtisculi papillares into two fasciculi ;
by their subdivision, on the other hand, into
several smaller bundles, but so grouped that
the position of the smaller corresponds to the
larger; and by the smaller columns furnishing
a certain number of the cords usually given off
by the larger ; yet there appears to be a remark-
able similarity between the course and arrange-
ment of the chordae tendinese in all cases. The
object of this we will afterwards see when
inquiring into the precise manner in which
these valves prevent regurgitation into the auricle
during the systole of the ventricle. The origin
of the aorta is furnished with three semilunar
valves (fig. 269), which very exactly resemble
in their position, shape, and appearance those
placed at the commencement of the pulmonary
artery. They are somewhat stronger, and have
the corpora sesamoidea generally larger than
those in the pulmonary artery. Behind these
valves are three dilatations (sinuses of Valwlva)
upon the commencement of the aorta, similar
to, but more prominent, than those at the com-
mencement of the pulmonary artery (fig. 269).
It was maintained by several of the older
eminent anatomists that the semilunar valves
must necessarily cover the entrance of the
coronary arteries,* and that they were filled,
not during the passage of the blood along the
aorta, but by the falling back of part of it
during the diastole of the heart, or as Boer-
haave expressed it, " Hae arterise sunt in dias-
tole, dum reliquse corporis arterise in systole
constituuntur."f Haller mentions two circum-
stances which must satisfy every one, if any
thing more than the bare inspection of the parts
was necessary, that the coronary arteries are at
least generally filled in the same manner as the
other arteries which arise from the aorta, and
these are — 1st, the result of experiments on
living animals, where the blood is seen to spring
per saltum from the cut coronary arteries during
the systole of the heart ; 2d, when a fcetus is
injected by the umbilical vein, the coronary
arteries are also filled. More lately, however,
VaustJ has maintained that the origin of the
coronary arteries is generally covered by the
semilunar valves. He states that he has injected
a great number of hearts from the pulmonary
veins ; in some of these the injection passed
into the coronary arteries, but in by much the
greater number these vessels did not contain a
single drop of injection. On examination of
these cases he found that the semilunar valves
entirely covered the origin of the coronary
arteries. In attempting to ascertain this point
on the uninjected heart, we must bear in mind
the different conditions of the aorta in the living
body and after death. In the dead body the
sinuses ofValsalva are collapsed, so that the
semilunar valves can be laid over the origin of
the coronary arteries in some cases, where they

* Morgagni was doubtful in this matter, and
thought that he had observed them sometimes
covered by the valves, at other times free. Advers.
v., A nimadver. xxv.

t Institut. Med. 183.

J Recherchcs sur la Structure et les Mouvements
du CtRur, p. 22, (1821.)

would become free when the sinuses are dis-
tended as they are with blood in the living
body. Making every allowance for this source
of fallacy, I am satisfied that I have seen one
or two cases in which these valves appeared
fairly to cover the origin of the coronary arteries.
Supposing that the origin of the coronary
arteries were covered in some instances by the
valves, it would in all probability be a matter
of little moment, as far as the efficiency of the
circulation through these arteries was concerned,
as long as the aorta retained its elasticity, for
the force with which it drives the distending
fluid backwards during the diastole of the
heart (a force which can be ascertained in the
dead body) would be sufficient to carry on the
circulation. The circumstances would, how-
ever, become very much altered in those cases
which are sufficiently common in advanced
age, where the aorta has from disease of its
coats entirely lost its elasticity, and the coronary
arteries have also become studded with calca-
reous matter, unless we suppose what could
scarcely happen, that the blood contained in the
sinuses is forced along the arteries when the
valves are thrown outwards."*

Septum of the ventricles. — The septum be-
tween the ventricles is triangular, and the apex
extends to the point of the heart. It is of
considerable thickness at the base, but becomes
thinner at the apex. Its position is oblique
like that of the heart. It is concave towards
the right ventricle, and convex towards the left.
From the slight rotation of the heart on its
axis, the anterior surface of the septum is
directed towards the right side, and the posterior
towards the left. It is composed, like the other
walls of the ventricle, principally of muscular
fibres, lined on the one side by the internal
serous membrane of the right ventricle, and on
the other side by the corresponding membrane
of the left.

We have preferred considering the relative
thickness of the parietes, the different capacities
of the several cavities of the heart, the relative
dimensions of the auriculo-ventricular, aortic,
and pulmonary orifices, and the size and weight
of the heart under distinct heads, not only as
this enables us to obtain a more connected
view than we could otherwise have done of
points upon which there are many conflicting
opinions, and upon which it is so frequently
necessary to possess, as far as we possibly can,
accurate notions in deciding upon the normal
or abnormal state of the organ, but we were
also afraid that if mixed up with the other parts
of the descriptive anatomy they would have

* Among the numerous and striking examples
which the history of medical science furnishes us
of the powerful tendency which preconceived
notions have, if not powerfully guarded against,
of influencing our observations of the plainest facts,
we may instance the statements of Petriolus on this
question. He, apparently deeply imbued with the
old hypothesis that the heart is the seat of courage,
maintained that in bold and carnivorous animals
the coronary arteries were above the valves ; in
timid and herbivorous animals, on the contrary,
they arose behind the valves, while in man they
were of uncertain origin, as he was bold or timid.

HEART.

585

rendered it more complicated. We will find
that considerable differences in these respects
may exist between different hearts and between
different parts of the same heart, which, to
judge from the perfect regularity with which all
its functions proceeded before death, must be
considered as perfectly healthy ; and it is from
this want of uniformity in the different parts of
apparently healthy hearts that we can in some
measure account for the discrepant statements
en this subject which exist in the works of the
most celebrated and accurate anatomists.

Thickness of the walls of the several cavities
of the heart. — The left auricle is somewhat
thicker than the right, and the left ventricle
very considerably thicker than the right. Bouil-
laud* found the average thickness of the walls
of the left auricle in four healthy hearts to be
lg lines, and that of the right auricle to be
1 line. Lobstein has rather strangely stated
that the right auricle is twice the thickness
of the left. He makes the thickness of the
right auricle to be 1 line, and that of the left
to be only £ line. Laennec reckons the relative
proportion of the thickness of the left ventricle
to the right as rather more than 2 to 1.
Bouillaud found the average thickness of the
right ventricle at its base in a great number
of cases to be 2£ lines, and that of the left
ventricle at the same part to be 7 lines.
Cruveilhierf states the proportionate thickness
of the right to the left ventricle as 1 to 4,
or even as 1 to 5. According to Soemmerring,f
the relative thickness of the two ventricles
is as 1 to 3. Andral§ states that in the adult
the thickness of the left to the right ventricle
is as 2 to 1, but in infancy and in old age
it is as 3 or 4 to 1.

M. Bizot has lately published the results
of the careful measurements of the healthy
heart in one hundred and fifty-seven indivi-
duals of all ages. || The greater part of these
observations were collected at La Pitie, under
the auspices of Louis. According to M. Bizot,
the heart goes on increasing in all its dimen-
sions— length, breadth, and thickness — up to
the latest periods of life. The growth is,
however, more rapid before twenty-nine years
than after that age. While, then, the muscles
of animal life are diminishing in size in ad-
vanced life, the heart is still increasing in
bulk. The heart of the male is, on an average,
larger than that of the female at all the different
stages of life. M. Bizot remarks that the
longitudinal section of the left ventricle is
fusiform, the thickest part being situated at
the junction of the superior third with the
middle third.^I The thickness of this ventricle
goes on increasing from youth up to advanced
age. The following are a few of the measure-

* Traite Clinique des Maladies du Coeur, t. i.
p. 53. 1835.

t Anatomie Descriptive, t. iii. p. 17.

J De Corporis Humani Fabrica, t. v.

6 Anatomie Pathologique, t. ii. p. 283.

fj Memoires de la Societe Medic. d'Observation
de Paris, t. i. p. 262. 1836.

f Op. cit. p. 269 and 284.

ments of the thickness of the walls of the
ventricles given by M. Bizot.

Left ventricle, male.
Age. Base. Middle part. Apex.

1 to 4 years .... 3 lines. 2-& lines. 1-& line.
50 to 79 years . . 4§J „ 5§| „ 4^ „

Left ventricle, female.

1 to 4 years .... 2^ lines. 2 1 lines. 2^3 lines.
50 to 89 years . . 4£ „ 5 „ 3| „
Average from 16 { .3 ,4 ~I3

to 89 years . . > 4« " *3 "
Thickness of right ventricle. — The thickest
portion of the right ventricle is not placed,
as M. Bizot remarks, at the same point as
in the left. In the right ventricle it is at the
base of the heart, 4 lines below the tendinous
ring. The thickness of the walls of the right
ventricle, unlike the left, remains more nearly
stationary at the different periods of life. They
are, however, a little thicker in advanced age
than at an earlier period of life.

Right ventricle, male.
Age. Base. Middle part. Apex.

1 to 4 years .... f0 line. T65 line. ,$ line.
30 to 49 years . . Iff „ 1& „ 31 „
50 to 79 years . . 27»g „ 1-J& „ ft „
Average from 16}1113 1 99 12
to 79 years . . * HW » ^« »

Right ventricle, female.
1 to 4 years .... 1^ line. | line. ^ line.
30 to 49 years .. 1$ „ Ii3( „ |* „
50 to 79 years . l\ „ i\ „ 1 „
Average from 15 } 12 17 ^3

to 59 years .. 5 3 " * "
Care was taken to make all these measure-
ments at points where there were no columnae
carneae.

The thickness of the septum ventriculorum,
according to Meckel, is 11 lines at its base.
Bouillaud obtained the same results in the
only case in which he appears to have measured
the thickness of the septum. M. Bizot has
given measurements of the ventricular septum
at six different periods of life, from which I
have selected the following.

Mtde. Female.

Age. Middle part. Middle part.

1 to 4 years 3^ lines. 2| lines.

16 to 29 years .... 4T| „ 4£ „

50 to 79 years. ... 5£ „ 5^ „

The thickness of the septum ventriculorum
goes on increasing in thickness from infancy
to an advanced period of life.

Relative capacities of the several cavities. —
The most conflicting statements exist upon
this point, and we find it perfectly impossible
to come to any satisfactory decision. Each
cavity of the heart is supposed, when mo-
derately distended, to contain rather more than
two ounces of fluid. The auricles may be
safely said to be of less capacity than the
ventricles; and this disparity is strikingly
marked in the larger animals, as the horse
and ox. The right auricle is generally allowed
to be larger than the left, and the difference,

586

HEART.

as stated by Cloquet and Cruveilhier, is as
5 to 4. The right ventricle is generally found
larger than the left after death. This difference
has been very variously estimated by different
anatomists. Some, as Winslow, Senac, Haller,
Lieutaud,* and Boyer, have maintained that
there is a marked disparity between the capa-
cities of the two cavities, while Meckel,
Laennec, Bouillaud, Portal, and others be-
lieved that this difference is to a smaller extent.
Lower was the first to maintain that both
ventricles are of equal size. Sabatier, Andral,
and others have supported this opinion ; while
Cruveilhierf states that he has satisfied himself,
from comparative injections of the two cavities,
that the left ventricle is a little larger than
the right. Gordon has occasionally found
both ventricles of equal size, and Portal has
seen them of the same size in young persons.
Santorini and Michelattus believed that, though
the capacity of the left ventricle appears a
little smaller than that of the right, yet that
the superior force of the left auricle over the
right dilates the left ventricle sufficiently to
render it equal to the right.

The majority of anatomists, however, have
always maintained that the capacity of the
right ventricle is greater than that of the left,
and have adduced the following arguments in
support of this opinion: 1, that the right
auricle, right auriculo-ventricular orifice, and
origin of the pulmonary artery are larger than
the auricle and corresponding orifices of the
opposite side : 2, that when both ventricles
have been filled with water, mercury, or wax,
more of these substances is found contained
within the right than the left : 3, the experi-
ment of LegalloisJ shew that when an animal
is bled to death, this disparity between the
size of the ventricles is still found. Those
who maintain that the capacity of these two
cavities is equal do so on the following
grounds: — 1, that as the walls of the right
ventricle are weaker than those of the left,
when the same force is used in injecting both,
the right must, as a matter of course, be more
dilated than the left. 2. Sabatier ingeniously
suggested that, as during the last moments of
life the passage of the blood from the right side
of the heart is generally impeded, producing
engorgement of that side, while the left side
was generally empty, this might account for
the greater size of the right ventricle. 3.
Sabatier and Weiss§ maintained that in those
cases where the kind of death was such that
the right side of the heart could not be en-
gorged as in fatal haemorrhage, no difference
between the capacity of the two sides could

* Memoires de 1' Academic Roy. des Sciences,
t. viii. p. 561, 1754. Lieutaud's authority is some-
times quoted in support of the opinion that these
cavities are of equal capacity.

f Anatomic Descriptive, t. iii.

J Dictionnaire des Sciences Med. t. v. p. 436.
These experiments were performed upon dogs, cats,
guinea-pigs, and rabbits.

§ De dextro cordis ventriculo post mortem am-
pliore.

be observed. 4. The experiments of Sabatier,
in which, after tying the aorta and producing
engorgement of the left side of the heart,
while the right side was emptied by a wound
made into the vena cava or pulmonary artery,
the left ventricle was found to be of greater
capacity than the right.

M. Bizot maintains that the capacity of the
ventricles goes on increasing from youth up
to old age; and that this, contrary to the
opinion of Beclard, is not so rapid in old
age as in the earlier periods of life. The
following are a few of M. Bizot's measure-
ments: —

Left ventricle, male.
Age. Length. Breadth*

1 to 4 years ...... 20 lines. 31 lines.

50 to 79 years ---- 36 „ 56f „

Average from 15 to ) 24

79 years

-49
54SI

Left ventricle, female.

1 to 4 years 18| lines. 29| lines.

50 to 79 years 31 „ 49| „

Average from 15 to > q1 i 4p23

89 years } JJ^ "

Right ventricle, male.

1 to 4 years 20^ lines. 47f lines.

50 to 79 years .... 37£ „ 87 „

Average from 15 to > Q7,H

79 years } 37« » ^BO »

Right ventricle, female.
1 to 4 years ...-,.. 18| lines. 44| lines.

50 to 79 years 35ft „ 76 „

Average from 15 to ^ „ . -,,,

89 years $

Every one must confess that the right ven-
tricle is generally found larger after a natural
death in the human subject than the left ; and
it appears exceedingly probable that these two
cavities, in the healthy state of the organ,
contain different quantities of blood during
life. As the capacity of the auricles is rather
smaller than that of the ventricles, it may
be asked how can the auricles furnish blood
sufficient to distend the ventricles? We shall
afterwards more particularly explain that the
blood passes from the auricles into the ven-
tricles at two different times during the interval
between each contraction, viz. at the moment
of its relaxation, and again during the con-
traction of the auricles. Various attempts
have been made by those who maintain that
the right side of the heart is larger than the
left, to explain how the equilibrium of the
circulation can be maintained. Helvetius*
supposed that this could be accounted for
by the diminution which the blood suffered
in passing through the lungs ; and in proof
of this he erroneously maintained that the
pulmonary arteries were larger than the pul-
monary veins. Legallois believed that this
could be explained (as appears very probable)
by the greater size of the right auriculo-ven-
tricular opening, allowing a greater reflux of
blood back again into the auricle, during the
systole of the ventricles.

* Mcnioire de 1'Acad. Roy. 1718, p. 285.

HEART.

587

Relative dimensions of the auricula -ven-
tricular orifices. — The right auriculo-ventricular
orifice is larger than the left, as was correctly
stated by Portal.* According to Cruveilhier,
the largest diameter of the right auriculo-
ventricular opening which is antero-posterior
is from 16 to 18 lines, and its smallest diameter
is 12 lines; while the largest diameter of the
left auriculo-ventricular opening, which is di-
rected almost transversely, is from 13 to 14,
and its smallest is from 9 to 10 lines. Bouillaud
gives the results which he obtained from the
accurate measurement of the circumference of
these two openings in three perfectly healthy
hearts. The average circumference of the left
auriculo - ventricular opening was 3 inches
6^ lines : the maximum was 3 inches 10 lines,
and the minimum was 3 inches 3 lines. The
average circumference of the right auriculo-
ventricular opening was 3 inches 10 lines : the
maximum was 4 inches, and the minimum
was 3 inches 9 lines.

Circumference of the aortic and pulmonary
orifices. — The circumference of the aortic and
ventriculo - pulmonary orifices is sometimes
nearly equal ; more generally, however, the
ventriculo-pulmonary is the larger. Bouillaud
gives the following measurements of these
openings taken from four healthy hearts : —
Average circumference of the aortic opening,
2 inches 5$ lines: the maximum 2 inches
8 lines, and the minimum 2 inches 4 lines.
Average circumference of the ventriculo-pul-
monary opening, 2 inches 7f lines : the
maximum 2 inches 10 lines, and the minimum
2 inches 6 lines. I have found this difference
between the circumference of these two open-
ings marked distinctly at seven years of age.
M. Bizot has given measurements of the ar-
terial orifices, of which the following is the
average.

Aortic orifice, male.

Average from 16 to 79 years. . 45$ lines.

Aortic orifice, female.

Average from 16 to 89 years . . 41£ lines.
Pulmonary orifice, male.

Average from 16 to 79 years . . 54^ lines.
Pulmonary orifice, female.

Average from 16 to 89 years . . 48 j lines.

Size and weight. — Laennec has stated that
the size of the heart in general nearly corre-
sponds to the closed fist of the individual.
This can only be considered as a loose ap-
proximation, as the size of the hand may vary
in different individuals otherways resembling
each other, either from original conformation
or from dissimilar modes of life ; and, besides,
the size and form of the healthy heart itself
may vary sufficiently to effect an apparent
difference in these respects.

The average length of the heart, according
to Meckel, is 5£ inches, of which about
4 inches are to be allowed for the ventricles,
and 1 2 inch for the auricles. Bouillaud found
that a line drawn from the origin of the aorta
to the point of the heart ranged, in nine

* Anatomic Medicalc, t. iii. p. 69.

healthy hearts, from 4 inches to 3 inches
2£ lines. The average length was 3 inches
7^ lines.

The weight of the heart, according to
Meckel, is about 10 ounces, and its propor-
tionate weight to the whole body is as 1 to 200.
Tiedemann is of opinion that the proportionate
weight of the heart to the body is as 1 to
160.* The weight of the healthy and empty
heart, according to Cruveilhier, is from 7 to
8 ounces. Bouillaud found the average weight
in thirteen healthy hearts to be 8 ounces
3 drachms. According to Lobstein it weighs
between 9 and 10 ounces. The size and
weight of the heart must generally be to a
great extent in conformity with the size and
weight of the body. In an athletic male we
would expect it to weigh about 10 ounces, in
an ordinary-sized individual about 8 ounces,
and in weakly persons, or in cases of pro-
tracted debility, it would be still more dimi-
nished in weight. For the same reason it is
generally larger and heavier in males than
in females.

Structure of the heart. — The heart consists
of muscular and tendinous textures, of cellular
tissue, of bloodvessels, of nerves, and of lym-
phatics, enclosed between two serous mem-
branes.

Tendinous texture. — The tendinous texture
of the heart is placed, 1, around the auriculo-
ventricular and arterial orifices ; 2, within the
reduplicature of the lining membrane forming
the auriculo-ventricular and arterial valves; 3,
it forms the chordae tendineae.

Auriculo-ventricular tendinous rings. —
Around each auriculo-ventricular opening we
find a tendinous circle or ring, from the upper
part of which the muscular fibres of the au-
ricles arise, and from the lower part those of
the ventricles, thus affording perhaps the only
example in the human body of a strictly in-
voluntary muscle having tendinous attach-
ments. The tendinous ring surrounding the left
auriculo-ventricular opening is stronger than
that surrounding the right. These tendinous
zones are thicker along the lower edge where
the muscular fibres of the ventricle are attached,
and become thinner along the upper edge where
the muscular fibres of the auricles are attached,
so that the fat occupying the auricular groove
is seen through the upper portion of the ring
on the right side. The right margin of the left
auriculo-ventricular ring is connected with that
surrounding the aortic opening. The existence
of the auriculo-ventricular and arterial tendi-
nous rings was well known to Lower.f

Arterial tendinous rings. — The form of the
tendinous rings surrounding the arterial open*
ings, and the manner in which the large arte-
ries are attached to their upper edges, have not,
I think, been described with sufficient accu-
racy. These textures are very plainly observed

* If we consider the ordinary weight of an adult
heart to be 8 ounces, and the average weight of
the whole body to be 150 Ibs. the proportionate
weight of the heart to the body would be as 1
to 225.

t Tractatus De Corde, p. 29. 1669.

588

HEART.

in the heart of the ox and horse after a little
dissection. The following description is drawn
up from numerous dissections of these parts
made on the human heart. The tendinous ring
surrounding the aortic opening is stronger and
thicker than that surrounding the orifice of the
pulmonary artery. Both of them are stronger
than the auriculo-ventricular rings. Each of
the arterial rings appears as if composed of
three semilunar portions placed on the same
plane, the convexities of which are turned
towards the ventricles and the concavities to-
wards the vessels (fig. 266, a a).* Each of

Fig. 266.

Fig. 267.

Appearance of tendinous ring at the origin of the
pulmonary artery. In slitting open the artery,
one of the three projecting extremities of the ten-
dinous ring has been divided.

these semilunar portions has its projecting extre-
mities intimately blended at their terminations
with the corresponding projecting extremities
of those next to it, (Jig. 266, 6 b,) so that the
three form a complete circle, with three trian-
gular portions projecting from its. upper edge.
The semilunar portions approach fibre-carti-
lage in their structure, and have the intervals
left between their convex edges filled with a
texture more decidedly fibrous, (fig. 266, d,)
and which is considerably weaker than the se-
milunar portions, more particularly on the left
side of the heart.f The thinness of the ten-
dinous structure filling up these intervals has
led some anatomists erroneously to describe
these portions of the heart as protected only
by the two serous membranes. The right ten-
dinous zone is broader than the left and very
thin, particularly at its inner margin, at which
part in both sides of the heart it assumes more
of the tendinous than of the fibro-cartilaginous
structure. These tendinous rings are placed
obliquely from without inwards and from above
downwards, so that the outer edge is on a plane
superior to the inner. The sigmoid valves are
attached to the inner edge of the upper surface,
(Jig. 267, a,) and the tendinous fibres placed
in the fixed margins of these valves contribute
to the thickening of the ring at this part ; the
middle coat of the arteries is connected to the
outer edge of the same surface, and to the an-
terior part of the projecting extremities, (Jig.
267, b ;) while the muscular fibres of the ven-
tricles (fig. 266, /; fig. 267, /J are attached
to the lower surface of the projecting portion
of the convexity, and to the lower margin of
the fibrous tissue filling up the space between
the convexities of the projecting ends, (fig.

* These tendinous festoons are represented
stronger in the woodcut than they are naturally.

t These intervals are occupied by muscular nbrcs
in the heart of the ox and horse.

Pulmonary artery slit open at its origin, its internal
membrane stripped off, and two of the sigmoid valves
completely removed.

a a a, tendinous festoons.

b b, muscular fibres of the right ventricle.

c c c, middle fibrous coat of the artery after the
internal serous membrane has been stripped off.

g, small portion of one of the semilunar valves
left to show its attachment to the inner edge of the
upper surface of the tendinous festoon.

267, d.) There is, however, this difference
between the right and left arterial openings
with respect to the attachment of the muscular
fibres; — on the right side the muscular fibres
arise from the projecting portion of the con-
vexity of the whole three tendinous festoons,
(Jig. 268, c, ct) while in the left side the mus-

Fig. 268.

cular fibres are attached only to one and part
of a second, (fig. 269, b b,) as the larger lip
of the mitral valve (Jig. 269, a) is suspended

Fig. 269.

HEART.

589

from the posterior or left, and a, great part of the
anterior, — in fact to that part of the tendinous
ring which separates the aortic from the auri-
culo-ventricular opening. From the posterior
part of that portion of the tendinous ring to
which the mitral valve is connected, the ante-
rior fibres of both auricles, near the septum,
arise. As the left tendinous ring is thicker and
narrower than the right, there is a larger space
left between the fixed edge of the valves and
the attachment of the middle coat of the arte-
ries than there is on the left side. This space
is of some importance, as upon it a consider-
able part of the pressure of the column of
blood in the large arteries must be thrown
during the diastole of the ventricles.

There is a good representation of these ten-
dinous rings given in Tab. II. Opera Valsalvae,
torn. i. At page 129 they are thus described :
" In horum sinuum ambitu qua valvulae si-
nubus annectuntur quidem quasi Agger videtur
occurrere substantial durioris ad similitudinem
cartilaginis tarsi palpebraruin." I find also
that Gerdy* appears to have had an accurate
notion of the form and appearance of these ten-
dinous rings. He was aware of the existence
of the projecting angles of the tendinous ring
which pass up between the festoons of the
middle coat of the arteries, and which have
been overlooked in succeeding descriptions. I
find also that the late Dr. A. Duncan, jun. has,
in his unpublished manuscript, given a very
accurate account of these structures in the heart
of the ox.

Tendinous structure in the auriculo-ventri-
cular valves. — Distinct tendinous fibres exist
in the auriculo-ventricular valves enclosed be-
tween the reduplication of the lining serous
membrane. These are continuous with the
auriculo-ventricular tendinous zones, and are
most distinct and of great strength at the base.
I could never observe any distinct traces of mus-
cular fibres in these valves in the human heart
either when fresh or after long boiling. Bouil-
laud has, from the examination of one incon-
clusive case, but principally from analogy with
the corresponding valves of the heart of the ox,
supposed that they may exist in some cases in
hypertrophy of the valves. In making exami-
nations of this kind we must be exceedingly
careful not to mistake the tendinous fibres
when tinged with blood for muscular fibres,
for under these circumstances they certainly at
all times assume the appearance of muscular
fibres .f

* Journal Complementaire, torn. x.

t In the heart of the dog 1 have seen a distinct
band of transverse muscular fibres in the base of
the larger lip of the mitral valve, but could never
satisfy myself of the existence of any longitudinal
muscular fibres. In the heart of the ox and horse
very distinct longitudinal muscular fibres are seen
in the valves of both sides of the heart, princi-
pally, if not entirely, continuous with the inner
layer of the fibres of the auricles. A greater part
pass over the inner surface of the tendinous rings,
and are firmly attached to the tendinous structure
of the valves, reaching nearly to the lower margin
of the smaller segments of the valves. The effect
of these fibres upon the movements of the valves
would form an interesting subject of investigation.

Tendinous structure in the arterial valves. —
Distinct tendinous fibres also exist in the arte-
rial valves, which must add considerably to
their strength and prevent their more frequent
rupture. Three of these tendinous bands in
each valve are stronger than the others, and
their position deserves attention, as they are
often the seat of disease. One of these
bands occupies the free margin of the valve,
and passes between the projecting extremities
of the tendinous festoons (Jig. 270, a). Upon
the middle of this band the corpus .Arantii,
which is formed of a similar texture, is placed.
The other band cornes from a point a little
above the middle of the projecting end of the
tendinous festoon (fg. 270, b), and passes
up in a curved manner towards the corpus
Arantii, leaving between it and the superior
band a triangular space on each side, in which,
if any tendinous fibres exist, they are exceed-
ingly obscure. These two tendinous bands
were well known to Morgagni. The third
band is placed in the attached margin of the
valve, and renders this part the thickest and
strongest. Between the middle band and the
attached margin of the valve a number of
weaker bands are placed, which also pass up-
wards, generally assuming a curved form. Mor-
gagni termed these lower and weaker fibres^/v?
carne&j but they evidently belong to the same
structure as the stronger bands. The arrange-
ment of these tendinous fibres is best seen in
the aortic valves, and the appearance exhibited
in the accompanying representation, (jig. 270,J

Fig. 270.

which has been taken from Morgagni, is not
always distinctly observed, where the valves
are perfectly healthy, but become sufficiently
obvious in certain cases of disease.

Attachment of' the middle coat of the arte-
ries to the arterial tendinous rings. — The inner
and outer serous membranes are continued from
the heart upon the arteries ; the one becoming
the inner coat of the arteries, and the other is
continued for a short distance upon their ex-
ternal surface. A thin layer of cellular tissue
also passes from the heart along the arteries
between their middle coat and their external
serous membrane. These are, however, so far
unimportant compared with the attachment of the
middle coat of the arteries to the tendinous fes-
toons which we have just described. The middle
coat is so very firmly and strongly attached both
to the external edges and to the anterior portion
of the upper part of these projecting extremi-
ties, (fig. 267, d,) that it can be detached with
great difficulty. Those fibres of the middle
coat attached to the projecting extremities,

590

HEART.

which are apparently of the same number and
thickness as in that portion of the artery im-
mediately above, form a distinct curved edge
(fig- 267, ej, as they pass from the extremity
of one festoon to the other. As we trace the
middle coat of the artery downwards into the
concavities formed by each festoon, we find
that below this curved edge they become stri-
kingly thinner and continue to diminish in.
thickness and in length, (since they can only
stretch between the projecting extremities,)
until we arrive at the bottom of the concavity.
These three thin portions of the middle coat
must then be placed behind the semilunar
valves, and correspond to the sinuses of Val-
salva.* The thinness of the middle coat at the
sinuses of Valsalva will render this portion of
the artery more dilatable, and predispose it
to rupture when its coats are diseased.-f The
tendinous zones are distensible, but to a con-
siderably less extent than the middle coat of
the arteries. I am not aware that this account
of the manner in which the middle coat of the
arteries is attached to the tendinous rings has
been previously given. I suspect, however,
that Dr. Duncan must have been perfectly
aware of it from some parts of his manuscript.
The differences between these tendinous fes-
toons and the yellow elastic coat of the arteries,
and the manner of their attachment, can easily
be made out in the human heart ; they are,
however, more apparent in the larger animals,
as the horse and ox. The different characters
of the two tissues are obvious at the first
glance after boiling, even in the human heart.
Muscular tissue.^ — The greater part of the

* So striking is the difference between the middle
coat as it fills up the concavity of these festoons,
and where it stretches between the projecting ex-
tremities in the hedgehog, that at first sight it ap-
pears to be deficient at that part.

t According to Valsalva aneurisms are frequently
found in this situation : "4Atque ^ic aortae sinus ,
maximus ille est, in quo saepe aneurysmata circa
praecordia contingunt, ut propria obseivatione
edoctus sum/' Valsalvae Opera. Epist. Anat.
ed. Morgagni, torn. i. p. 131. 1740. This greater
tendency to aneurismatic dilatation must depend
upon two circumstances. The increased calibre of
the artery at this part will increase the pressure
upon its walls from the well-known hydrostatic law,1^
that " in a quantity of fluid submitted to compres-
sion, the whole mass is equally affected, and simi-
larly in all directions," and the diminished thick-'
ness of the middle coat will materially favour this
distending force.

J While I was engaged in examining the arranged
ment of the muscular fibres of the heart, Dr. Alison-
had the kindness to procure for me the manuscript
of the late Dr. A. Duncan, jun. on this subject. It
was well known not only in this country but on tliQ
continent that Dr. Duncan had for a very long pe-
riod attended very particularly to this question, anct
was in the habit of demonstrating the parts he, had
ascertained to his pupils. Unfortunately his inten-
tions of publishing on the subject were never car-
ried into execution, and his papers referring to it
were left in so confused a state that it is exceed-
ingly difficult and in most parts impossible to make
out the description. I have availed myself of those
parts that are legible in the following pages, and
these I have scrupulously acknowledged. Dr. Dun-
can's dissections of the heart were taken entirely
from the ox and sheep.

heart is composed of muscular fibres arranged
in a very intricate manner. These fibres are
connected together by cellular tissue,* which,
however, exists in much smaller quantity in
the heart than in the other muscles of the body.
These fibres are attached generally by both
extremities to the tendinous rings situated
around the orifices of the heart ; the fibres of
the auricles pass upwards to form the auricles,
and those of the ventricles downwards to form
the ventricles, so that., these tendinous rings
must form the fixed points towards which all
the contractions of the heart take place. None
of the muscular fibres of the auricles are con-
tinuous at any part with those of the ventricles,
and we will find that while some of them are
confined to a single auricle, others belong to
both. In the same manner a great part of
the fibres of the ventricles are common to
both, and are interwoven together, while others
again belong exclusively to a single ventricle,
or, as Winslowf expressed it, the heart is com-
posed of two muscles enveloped in a third.
The intimate arrangement of these muscular
fibres, particularly those of the ventricles, is
exceedingly complex, as the contraction of the
organ is not in one particular direction only,
but in all directions, and has long been con-
sidered as a kind of Gordian knot in anatomy.
Vesalius, Albinus, and Haller J confessed their
inability to trace them, and more lately De
Blainville§ assures us, from his own experi-
ence, that we can only arrive at very general
conclusions (des chases trcs-gtnerales) on this
• subject. By adopting the method of long-
continued boiling of the organ before com-
mencing to attempt to trace the course and ar-
rangement of its fibres, we will find that after a
few trials several of the most important points
connected with the distribution of these can be
ascertained, and by perseverance they can be
unravelled to a great extent. By long boiling
the muscular fibres are rendered hard and firm,
while the tendinous and cellular tissues are
softened or dissolved, and the fat melted. Dr.
Duncan, who employed this method to a great
extent, states that the essential circumstance is
to continue the boiling long enough, and that
he has never been able to carry it too far. I
have found from eighteen to twenty hours gene-
rally sufficient for this purpose. Some have
recommended that the heart should be pre-
viously put for a short time into a strong solu-
tion of salt, and Vaust advises that it should
be boiled in a solution of nitre, for the purpose
of rendering the fibres firmer. The boiling is
infinitely superior to the maceration in vinegar.
By stopping the boiling before the tendinous
rings are rendered too soft, we can easily see
their form and their connexions to the muscular
fibres.

The general connexion and distribution of

* [This however is denied by other observers,
and from very recent and careful examinations.
See the succeeding article by Mr. Searle. — ED.]

t Memoires de 1'Academie Royale des Sciences,
1711, p. 197.

t El. Phys. torn. i. p. 351.

§ Cours de Physiologic, &c. torn. ii. p. 359.

HEART.

591

the muscular fibres of the ventricles may be
stated to be as follows. 1st, Most of these
fibres are connected by both extremities to the
tendinous structure of the heart, a tact well
known to Lower,* though overlooked by many
subsequent anatomists. 2d, The direction of
these fibres is more or less oblique, a com-
paratively small part of them only being
vertical, and that too for a limited' part of
their course. The degree of obliquity of
these spiral turns is different in different por-
tions of the heart : they are more ob-
lique on the surface and less oblique
as we proceed to the deeper fibres,
more particularly at the base. The
deeper fibres approach more to the cir-
cular form. 3d, As has been already
stated, part of these fibres are common
to both ventricles; while part only
belong exclusively to a single ventricle,
and that principally at the base. 4th,
The external fibres are longer than the
next in order, and after turning round
the apex pass upwards into the interior,
below the lower margin of the shorter
fibres, and form the inner surface of
the ventricles, while the deeper again
turn up below the lower margin of the
fibres next in succession, so that the
longer enclose by their two extremities
all the shorter fibres. By this arrange-
ment we can explain how the base and
middle part of the ventricles should
be much thicker than the apex. This
arrangement has been particularly in-
sisted upon by Dr. Duncan and Gerdy,
and to illustrate it Gerdy has given an
ideal illustration, of which fig. 271 is a
copy.

Fig. 271.

run in a spiral manner from above downwards
and from right to left, while those on the pos-
terior surface, which are in general more ver-
tical, run from left to right. Most of these
bands are thin and broad at the upper part,
and become narrower and thicker as they ap-
proach the apex, where they form a remarkable
twisting, which has been termed the vortex,
(of which jig. 272, taken from the human heart
after boiling, is an accurate representation,) and
then pass in to assist in forming the inner surface

Fig. 272.

of the left ventricle and the columnae carnece.
The manner in which the external fibres turn
in at the apex to form the inner surface of the
ventricles and enclose the deeper fibres was
well known to Lower, and he has illustrated
it by an engraving, of which Jig. 273 is a copy.

Fig. 273.

In examining the course of the fibres of the
ventricles we shall not attempt to describe each
particular band of fibres, but confine ourselves
to their general arrangement.f In examining
the surface of the ventricles the superficial
fibres of the anterior surface are observed to

* Tractatus de Corde. p. 34 to 37. Lugd. Batav.
1669.

t Wolff has named and minutely described eight
distinct bands of muscular fibres on the surface of
the right ventricle : Acta Petropolit. pro anno 1781,
torn. viii. p. 251, 1785.

592

HEART.

This arrangement of the external fibres was
also well known to Winslow* and Lancisi.f
Winslow, however, denied that they described
the figure of eight, as stated by Lower. More
lately Gerdy has given a description of this
arrangement, to which he has added an en-
graving, which approaches more to the ap-
pearance of the perfect figure of eight than
that given by Lower. I, however, prefer that
given by Lower, as it more nearly resembles
the arrangement which I have myself seen in
tracing these fibres. A small part of the right
and posterior side of this vortex is formed by
fibres from the posterior surface of the left
ventricle, and from that part of the posterior
surface of the right ventricle near the septum,
and are attached above to the auricular tendi-
nous rings, while the whole of the anterior and
left side of the vortex is formed by fibres from
the anterior surface and right margin of the
ventricles. On tearing these last fibres, which
form the principal part of the apex, from the
anterior surface of the left ventricle, we find,
as we proceed upwards, that a comparatively
small part of them cross the anterior fissure
upon the right ventricle to reach the right au-
ricular tendinous ring. The greater number
dip in at the anterior longitudinal fissure, and
we shall afterwards find that they can be traced
to the base of the septum of the ventricles.
By tearing off these fibres downwards, we open
into the apex of the left ventricle. A general
notion of the manner in which these fibres,
passing from the base of the septum, turn in
at the apex, and proceed upwards on the inner
surface of the left ventricle, may be obtained
from Jig. 273. To have been quite accurate
the inner fibres should have been more scat-
tered, and some of them represented as termin-
ating in the columnae carneae. By unravelling
the fibres which form the apex, we may open
into the interior of the left ventricle without
breaking a single muscular fibre. Having thus
opened the apex of the heart, although the
point is removed, the circular edge is left entire
(fig- 274, a), and is formed of another series

* Memoires de 1'Acad. Roy. 1711. p. 197.
t De Motu Cordis : Opera omnia. torn. iv. p. 96.
1745.

of fibres, which, like those taken away, ad-
vance spirally from the base to the apex, and
turning over the edge (fig. 274, b} ascend in
the opposite direction, continuing their course
after being reflected. " Proceeding in the
same manner the whole apex of the left ven-
tricle may be removed, and the same principle
of arrangement is found throughout the whole
heart even to the base. When we get down as
far as the apex of the right ventricle, although
the principle remains the same, its effects are
more complicated, as it applies to two cavities
instead of one." I have frequently satisfied
myself of the correctness of the description
contained in this passage, which I have quoted
from the manuscript of Dr. Duncan. This is
the same kind of arrangement which, we have
already stated, has been insisted upon by
Gerdy, but which we believe can be more
satisfactorily seen by tracing the fibres in this
manner. Gerdy lays it down as a general law,
that all the fibres of the heart form loops, the
apices of which look towards the apex of the
heart (fg. 271). I find that Dr. Duncan
states that while the apices of those loops
which form the lower part of the heart point
to the apex, as Gerdy has described, " yet he
commits a great error when he asserts that the
apices of all the fibres of the heart point in
that direction, since the number of tops which
point in the opposte direction is not less." *
When the superficial fibres of the heart have
been removed as represented in Jig. 274, we
will find that if we trace the great mass of
fibres occupying the lower and middle part of
the left ventricle, they will be seen to run
spirally in strong bundles from above down-
wards and from right to left, to wind round
and form the posterior as well as the anterior
part of the point of the heart; that the greater
mass pass in at the apex of the left ventricle to
assist in forming the columnae carneae and in-
ternal suiface, while others pass in at the apex
of the right ventricle, and others again, after
turning a little upwards, dip into the interior
below some of the higher fibres. On tracing
them upwards, on the other hand, they dip in
at the anterior longitudinal fissure (fig. 274, d)
where they are as it were dovetailed with other
fibres from the anterior surface of the right
ventricle passing in at the same fissure, and
then mount almost vertically upwards to the
base of the septum, forming part of the sep-
tum of the right ventricle, only separated from
its lining membrane by a thin layer of fibres,
and are inserted in a strong band in the ox
into the bone of the heart, which is placed
between the auriculo-ventricular openings and
aorta, while in the human heart they are spread

* I could not discover in Dr. Duncan's manu-
script any other description or allusion to the fibres
here mentioned whose arrangement is opposed to
the general law which Gerdy is anxious to establish.
There is no doubt, however, that many of these
loops at the base are principally directed to the
periphery of the organ, and very little downwards,
and that a few in the infundibulum are slightly
directed upwards.

HEART.

593

over a wider surface at this their upper in-
sertion. I have been more particular in
describing this part of the heart, as this ar-
rangement of the fibres appears to me to be
intimately connected with the production of
the tilting motion of the heart. The fibres
which occupy the upper part of the anterior
surface of the left ventricle, as well as those
occupying the upper part of the posterior
surface (nearer the base than those bands
already described as passing from the ante-
rior surface), partly dip into the interior of
the left ventricle as they wind round it,
partly pass in at the posterior longitudinal
groove to assist in forming the septum, while
other strong bands, more particularly near the
base, cross this groove and dip into the interior
of the right ventricle. In the human heart
I have stripped off pretty strong superficial
bundles from the upper part of the posterior
surface of the left ventricle over the posterior
longitudinal groove, and over the surface of
the right ventricle as far as the anterior longitu-
dinal fissure, into which they dipped. In
stripping off the fibres from the posterior and
anterior surface of the right ventricle at this
stage of the dissection, part of them disap-
pear in their course around the ventricle, where
they dip in to assist in forming the interior;
others proceed as far as the anterior groove
before they dip inwards; while part of the
fibres which arise from the conus arteriosus
cross the upper part of the anterior fissure
upon the anterior surface of the left ventricle,
where they pass into the interior of the left
ventricle. These fibres, crossing the anterior
surface of the right ventricle, and which dip
in at the anterior fissure, form the inner sur-
face of the septum of the right ventricle. On
tracing those fibres which dip inwards at so
many different points, they are observed to rise
upwards to the tendinous rings either directly
or indirectly through the medium of the chordae
tendinea?. In following the fibres in this man-
ner we perceive the intimate connexion that
exists between the two ventricles, and that their
contraction must be simultaneous. We also
see that comparatively few fibres cross the
anterior longitudinal groove except near the
base, while large bundles of fibres cross the
posterior groove. \Vhen these fibres crossing
the two grooves have been torn away, the two
ventricles become detached from each other.
By this time the apices of both ventricles have
been opened.

On examining the deeper fibres (which oc-
cupy that part of the heart near the base), they
are seen to form a series of curved bands, of
one of which Jig. 275 is a representation.
These bands are imbricated, the lower disap-
pearing by its internal extremity below the
higher, so as to be inserted by that extremity
into the tendinous rings at a point more in-
ternal than the corresponding extremity of the
higher bands. Some of these bands are com-
mon to both ventricles, others belong exclu-
sively to one. The fibres of the right ventricle
become very complicated where they form the
conus arteriosus and fleshy pons between the
VOL. n.

Fig. 275.

pulmonary artery and right auriculo-ventricular
orifice. The fibres of the left ventricle are
stronger and coarser than those of the right
ventricle, while those of the conus arteriosus
are still firmer than those on the lower part of
the right ventricle.* " There do not occur in
any part of the heart cellular sheaths or tenr
dinous aponeuroses dividing bundles of fibres
as separate muscular fasciculi. Although a
complex it is not a compound muscle, and
does not consist of a number of distinct bellies
or heads. The only thing approaching to this
structure are the columnar and a strong mus
cular stay between the peripheral and septal
wall of the pulmonic ventricle, and the re-
ticulated texture on the inside of the ventricles,
much more conspicuous in man than in oxen."
" Many fibres are attached to each other by
agglutination or in a manner not easily under-
stood." " Many fibres bifurcate, and the di-
vided fibres follow different directions : or two
fibres from different parts approximate, and at
last are united and proceed as one fibre. I am
doubtful if this can be considered as a tendinous
point of union of all three. These points of
union are often arranged in one line so as to
give some appearance of a pennated muscle,
but the tendinous points, if they exist, do not
adhere to form membranes or strings. This
bifurcation is very evident in the connection
of the septal with the peripheral walls of the

heart."t

The auricles are formed by two sets of fibres,
a superficial and a deep. The arrangement of
these two sets of fibres does not follow the
same laws as those of the ventricles. The su-
perficial layer (fig. 276, a a, fig. 277, a a),
surrounds the base of the auricles, and is of
unequal height and thickness. It is broader
on the anterior and narrow on the posterior
surface, more particularly on the posterior and
outer part of the right. It extends upwards
towards their superior edge on the anterior
surface, and on the posterior surface of the
left as far as the inferior pulmonary veins.
It is very thin, particularly on the outer
and posterior part of the right auricle. In its
course round the auricles the fibres diverge to
enclose the appendices, and the orifices of the

* Dr. Duncan has given a very minute descrip-
tion of the fibres of this and other parts of the
heart, which are much too long for insertion here.
He has also given a very accurate and minute de-
scription of the bone in the heart of the ox.

t Dr. Duncan-

2 tt

594

HEART.

Fig. 276.

large veins. These fibres cross transversely
between the anterior surface of the two auricles
and connect them together. These superficial
fibres are also prolonged into the interauricular
septum (fig. 277, f) to assist in forming the

Fig. 277.

circular band of fibres which surrounds the
fossa ovalis. Gerdy figures a superficial band
of fibres (Jig- 276, 6) as belonging exclusively
to the left auricle.

The deep fibres belong exclusively to a sin-
gle auricle. They are superficial at various
parts, where the external or circular fibres are
deficient. By their inner surface they are con-
nected to the inner membrane of the auricles, and
a thin layer of cellular tissue unites their outer
surface to the inner surface of the superficial
fibres. In the left auricle Gerdy describes,
1st, a left auricular loop (fig. 276, c c, fig. 277,
c c), which embraces the auricle from its su-
perior edge to its base, which runs a little
obliquely to the left, before, above, and then
behind the auricle, and is attached by its ex-
tremities to the auricular tendinous ring near
the septum. It is contracted at that part where
it passes between the pulmonary veins. 2d.
The pulmonary veins are surrounded by circu-
lar fibres (fig. 276, d d, fig. 277, d d), which
are continued along their course to a variable
extent,' — sometimes they merely surround the
termination of one or more of these veins,
at other times I have seen them prolonged out-
wards as far as the roots of the lungs. These
fibres generally form a continuous layer, and

of sufficient thickness to render them capable
of constricting these vessels considerably. 3d.
Some fibres proper to the appendix (fig- 276,
m m\ which, by passing between and uniting
themselves to the other fibres of the appendix,
form that reticulated appearance which it pre-
sents in its inner surface. Some of these fibres
are circular, others form incomplete circles.

In the right auricle, Gerdy has described,
1st, a right auricular loop (Jig. 276, h A, fig.
277, A), which is attached anteriorly to the
tendinous structure at tne base of the auricle ;
it extends upwards in the anterior edge of the
septum auriculorum ; it then curves round the
fossa ovalis, of which it forms the projecting
edge, and at the orifice of the vena cava supe-
rior it divides into a right and left band. The
first proceeds downwards, becomes engaged
with some of the superficial fibres around the
cava superior, and forms the angle between
them (tuberculum Loweri), from which it
passes downward to the auricular tendinous
ring along the right side of the cava inferior.
The left division passes along the left side of
the cava inferior, in the posterior edge of the
auricular septum, where it intermixes with the
fibres which embrace the entrance of the coro-
nary vein. 2d, Some muscular fibres (fig.
276, p\ which pass between the anterior part
of the tendinous ring and the appendix. 3d,
Some circular fibres, which surround the en-
trance of the cava superior (fig. 276, o) : these
do not extend upwards beyond the orifice of
the vein. 4th, The bundles of fibres which
arise from the right side of the auricular ring
proceed upwards to the posterior part of the
appendix, and form the musculi pectinati
seen in the interior of the auricle. 5th, A few
fibres proper to the auricle (fig. 276, n\ which
assume the circular form. The action of all
these fibres superficial as well as deep must be
to diminish the capacity of their cavities, and
draw them towards the auriculo-ventricular
openings, and thus favour the passage of their
contents through these openings.

Inner membrane of the heart. — Each side of
the heart has its own lining membrane, and
both of these are closely allied to the serous
membranes in structure and appearance. They
are continuous with the inner coat of the vessels
which open into their different cavities. These
have been termed the endocarde by Bouillaud
to distinguish them from the serous coat of the
pericardium on the outer surface of the heart.
If we commence to trace the inner membrane
of the right side from the entrance of the two
cavae, we find that it is folded upon itself to
form the Eustachian valve at the entrance of
the inferior cava ; it then passes upon the inner
surface of the auricle, and at the opening of the
coronary vein it is again folded upon itself to
form the valve of the coronary vein. It passes
through the auriculo-ventricular opening, ad-
heres to the inner surface of the tendinous ring,
and is there folded upon itself to assist in form-
ing the tricuspid valve. It now proceeds upon
the inner surface of the ventricle, and at the
origin of the pulmonary artery it assists in
forming the semilunar valves, and becomes con-

HEART.

59i

tinuous with its inner coat. If w« trace the
inner membrane of the left side of the heart
from the entrance of the pulmonary veins, we
find that, after lining the auricle, it is continued
through the auriculo-ventricular opening, and
is there folded upon itself to assist in forming
the mitral valve. In the left ventricle it sur-
rounds the chordae tendineae and unattached
columnae carnese in the same manner as in the
right ventricle ; and at the origin of the aorta it
assists in forming the semilunar valve, and be-
comes continuous with the inner coat of the
artery. These membranes adhere intimately to
the inner surface of the heart by close cellular
tissue, and have their inner surface perfectly
polished and smooth. That of the left auricle
is thicker than that of the right. They are
thicker in the auricles than in the ventricles.
In the ventricles, except near the origin of the
large arteries, they are exceedingly thin.

Nerves of the heart. — The heart is supplied
with nerves from the sympathetic and par
vagum. The sympathetic branches come from
the superior, middle, and inferior cervical gan-
glia, and frequently also from the first dorsal
ganglion. The branches from the par vagum
come directly from the trunk of the nerve, and
indirectly from the recurrent or inferior laryn-
geal. The course of these on the right side
differs from those of the left in some respects,
and requires a separate description. These
nerves, like most of the other branches of the
sympathetic, are very irregular in their size,
number, and origin, so that it would be difficult
to find two subjects in which they are exactly
alike ; they are also very irregular in their
course before they reach the cardiac plexus,
but become more regular when they gain the
arteries of the heart, whose branches they ac-
company. These nerves, after forming diffe-
rent anastomoses and plexuses with each other
of the same side, converge at the upper and
back part of the arch of the aorta, where they
form a free anastomosis with those of the oppo-
site side, and then pass on to the heart. The left
cardiac nerves are sometimes much smaller
than those on the right side, so as to appear, as
in the dissection described by Lobstein,* merely
accessory to those on the right. On the other
hand the size of those on the left side may pre-
ponderate considerably over those on the right.
The proportional size of the different nerves of
the same side is also very various. When the
nerves of one side are small, the deficiency is
made up by the greater size of those of the op-
posite side ; and when any particular branch is
either unusually small or entirely wanting, its
place is supplied by the greater size of the
other nerves of the same side, or of those of the
opposite side. The branches from the par
vagum, particularly those coming from the re-
current, vary also considerably in size. All
the sympathetic branches of the cardiac plex-
uses are of a gray colour, and are generally not
so soft as Scarpa has described them.

The right cardiac branches of the sympathe-

* De Nervi Sympathetic! humani fabrica, &c.
pp. 16 & 18.

tic are generally three in number : 1st, superior
cardiac (supremus et superficialis cordis} arises
from the lower and inner part of the superior
cervical ganglion, or from the continuation of
the sympathetic between the superior and
middle ganglia, or from both these origins. It
generally also receives a filament from the par
vagura. In its course down the neck it lies
behind the sheath of the carotid artery. It
anastomoses with the external laryngeal nerve
and descendens noni, and sends a twig along
the inferior thyroid artery to the thyroid body ;
and at the lower part of the neck it sometimes
divides into two branches as figured by Scarpa,*
one of which unites itself to the middle car-
diac, the other forms an anastomosis with the
recurrent nerve of the same side. At other
times it passes into the thorax either in front or
behind the subclavian artery, takes the course
of the arteria innominata, and reaches the pos-
terior part of the arch of the aorta, where it
anastomoses with branches of the middle and
inferior cardiac nerves, or with branches of the
recurrent. It more rarely appears to pass to
the cardiac plexus without any anastomosis
with the middle and inferior cardiac branches.
It frequently presents a ganglion in its course
down the neck.

Middle cardiac nerve. — This nerve arises by
several short twigs from the middle cervical
ganglion. This is generally the largest of the
cardiac nerves, and is named by Scarpa the
great or deep cardiac nerve (n. cardiacus me-
dius, s. profundus, s. magnus). It proceeds
downwards and inwards, crosses the subclavian.
artery, sometimes in front, at other times it di-
vides into several branches, which surround the
artery and again unite. It anastomoses with
the branches of the recurrent, in the neigh-
bourhood of which it runs, also with the par
vagum, superior and inferior cardiac nerves ;
and following the course of the arteria innomt-
nata it passes behind the arch of the aorta to
terminate in the cardiac plexus.

Inferior cardiac nerve (n. cardiacus minor
of Scarpa). — This nerve generally arises by fila-
ments from the inferior cervical ganglion, some-
times from the first dorsal ganglion, at other
times from both. It proceeds behind the sub-
clavian artery near to the recurrent nerve. It
follows the course of the innominata close to
the middle cardiac, with which it anastomoses,
and proceeds to join the cardiac plexus.

Left cardiac nerves. — Perhaps the differences
in the course of the right and left cardiac nerves
are principally to be attributed to the known
differences between the large arteries of the two
sides. The left superficialis cordis is figured
by Scarpaf as dividing a little above the arch
of the aorta into four branches ; two of these
pass in front of the aorta to form an anastomo-
sis with a branch of the par vagum and deep
cardiac ; a third also passes in front of the aorta
to unite itself with the middle cardiac; and the
remainder of the nerve proceeds behind the
arch to unite itself with the cardiac plexus.

* Tab. iii. Tabulae Neurologic*, &e,
f Tab, iv. op. cit.

2R 2

596

HEART.

The left middle cardiac nerve is generally
smaller than the right, and is frequently partly
formed by a branch from the inferior cervical
ganglion. It passes behind the arch of the
aorta, sometimes in the form of a single trunk,
sometimes double, at other times triple, and
generally throws itself into the upper and left
part of the cardiac plexus.

Cardiac plexus (great cardiac plexus of
Haller) is placed behind the arch of the aorta
and in front of the lower part of the trachea,
extending from the arteria innominata to the
right branch of the pulmonary artery, and is
formed by the convergence of nearly the whole
of the cardiac nerves of both sides, but more
particularly of the middle cardiac nerves.
There is occasionally a distinct ganglion at the
junction of these nerves; more generally there
is only a plexiform arrangement. From this
plexus a very few branches pass upon the ante-
rior surface of the aorta (curdiaci superficiales
aorta), and anastomose with the right coronary
plexus : some twigs also pass backwards to
anastomose with the bronchial plexuses. By
far the greater part of the cardiac plexus pro-
ceeds to the heart in the form of two large
divisions to form the right and left coronary
plexuses which accompany the coronary arte-
ries. Where the right branch leaves the lower
part of the plexus there is a gangliform swelling
(ganglion of Wrisberg), which is occasionally,
however, very indistinct. This ganglion fur-
nishes the greater part of the superficial plexus
of the aorta which we have just described. This
great right cardiac branch divides into two
parts ; the smaller passes between the aorta and
pulmonary artery to reach the right side of the
origin of the pulmonary artery, where it attaches
itself to the right coronary arteiy to form the
principal part of the right coronary plexus ; the
other and larger portion creeps under the pul-
monary artery to the posterior part of the heart,
to assist in forming the left coronary plexus.
The great left cardiac branch, which principally
comes from the upper part of the cardiac plexus,
and at first passes from right to left posterior to
the ductus arteriosus, after which it is joined
by other smaller branches which pass in front
of the ductus arteriosus. It also divides into
two branches ; the smaller passes between the
aorta and pulmonary artery, and reaches the
origin of the right coronary artery, and throws
itself into the right coronary plexus ; the larger
bends round the posterior surface of the pulmo-
nary artery to reach the left coronary artery,
where it forms, with the larger branch of the
right, the left coronary plexus. There is thus
a free interchange of filaments between the
nerves of both sides. The left coronary plexus
is considerably larger than the right, in propor-
tion as the left side of the heart is thicker than
the right. These coronary plexuses consist of
a number of minute filaments which accom-
pany the ramifications of the coronary arteries
everywhere, and are distributed upon the sur-
face of the auricles as well as upon the ventri-
cles, They anastomose with each other upon
the anterior and posterior surface of the heart.
All the nerves of the heart enter into its sub-

stance upon the surface of the arteries, and
cannot be traced beyond the second or third
division of the arteries. The nerves of the
heart are generally considered to be small com-
pared to the size of the organ.* Though the
nerves of the heart are not equal in size to
those of the tongue and eye, yet Scarpa is
doubtful if they are not equal to the nerves of
the other voluntary muscles, as, for example,
the muscles of the arm. It must be remem-
bered that the minute subdivision and diffusion
of these nerves over a large extent of surface,
by which many of them can only be seen after
a minute examination, causes them to appear of
less size than what they collectively really are.
Soemmerring maintained that very few of the
nerves of the heart were distributed to the mus-
cular tissue of the heart, and that they more
properly belonged to the arteries : " nervi car-
diaci proprie ad arterias, ad aortam et arterias
coronarias pertinent, eaque filia subtilia nervo-
rum parum sibi (cordi) constant." f Behrends,
the pupil o| Soemmerring, affirmed that not a
single twig went to the muscular tissue of the
heart, but that they were entirely distributed on
the coats of the arteries.]; The announcement
of these opinions, bearing so directly as they do
upon the Hallerian doctrine of the nature of
irritability, so keenly agitated immediately be-
fore throughout Europe, could not fail to create
considerable sensation at the time, and it is
probable that to this we owe the splendid work
of Scarpa upon the nerves of the heart, which
has entirely set the question concerning the dis-
tribution of these nerves at rest. Scarpa has
shown that when followed to their minute dis-
tribution, the nerves of the other muscles ac-
company the arteries in the same manner as
the nerves of the heart, and that the nerves of
the heart only differ from those of voluntary
motion in this, that the nerves accompanying
the arteries of the voluntary muscles are firmer
and thicker than those of the heart.

Bloodvessels of the heart. — The heart is sup-
plied with blood by the two coronary arteries,
for a description of which see AORTA. The
blood is returned by the coronary veins. The
branches of the coronary veins generally accom-
pany those of the arteries. They are divided
into the larger coronary vein and smaller coro-
nary veins.

Great coronary vein (vena coronaria maxima
cordis). — This vein is formed by several
branches, three of which surpass the others
considerably in size. One of these lies in the
anterior louoitudinal groove ; another runs along
the obtuse or left margin of the heart ; and the
third, which may be replaced by two or three

* Bichat in his Anatomie Generale says, " that
the nervous mass intended for the muscles of orga-
nic life is much inferior to that of the voluntary
muscles. The heart and deltoid muscle, on being
compared together, display in this respect a very
considerable difference."

t Corporis humani fabrica, torn. v.

J Dissertatio qua demonstratur cor nervis carere.
After making this general statement, he admits, in
one part of his treatise, that he has traced two
twigs of the cardiac nerves into the substance of the
heart.

HEART.

597

smaller veins, runs along the posterior surface
of the left ventricle, between the obtuse margin
and posterior longitudinal groove. The first
of these is frequently described as the trunk of
the vein, and it commences at the apex of the
heart, where it anastomoses with the smaller
posterior and anterior veins. It runs upwards
in the anterior longitudinal groove along with
the left coronary artery, gradually increasing in
size as it ascends, from the junction of the other
veins. \Vhen it reaches the base of the ventri-
cles it changes its direction, enters the groove
between the left auricle and ventricle, leaves
the coronary artery, passes from left to right in
the posterior part of the same groove, when it
becomes considerably dilated (sinus of the co-
ronary vein). It then opens into the right
auricle at its lower and back part close upon
the posterior edge of the septum auriculorum.

Smaller posterior coronary vein (vena coro-
naria corclis minor). — It commences at the
apex of the heart, runs up in the posterior lon-
gitudinal groove, or a little to its right side, and
receives its blood principally from the right
ventricle. It generally joins the sinus of the
coronary vein ; at other times it enters the auri-
cle separately immediately by the side of the
great coronary vein, so that its aperture is also
covered by the coronary valve.

Smaller anterior coronary veins (ven<e inno-
minate of Vieussens). — These are very small
and variable in number, and are placed on the
anterior surface of the right ventricle. One of
these, larger than the others, (generally the su-
perior,) sometimes receives the name of ante-
rior vein of Galen. They frequently unite to
form a single trunk ; more generally perhaps
they continue separate, pass in front of the right
coronary artery as it lies in the auriculo- ventri-
cular groove, and enter the right auricle at its
anterior and inferior part. One of the musculi
pectinati overlaps their entrance, forming a kind
of valve.

Vena minim*, or veins of Thebesius, are
minute veins, which enter the auricle at various
points. It was maintained by Vieussens, The-
besius, and Ruysch, that some of the coronary
veins opened into the left side of the heart,
thus producing a slight intermixture of the dark
blood with the arterial. This has been more
lately asserted by Abernethy,* and has been
supposed to occur more frequently in phthisical
cases ; the difficulty of transmitting the blood
through the lungs causes their enlargement.
Such injections are liable to great fallacy, from
the great facility with which fine injections, or
even coarse injections when forcibly pushed
into the vessels, escape into the cavities of
organs. Especial care is, therefore, required in
conducting them. Notwithstanding that we
have the authority of some of the most accurate
anatomists in favour of this opinion, it is very
doubtful if any of these veins open into the left
side of the heart.f

* Philos. Trans. 1798.

t Professor Jeffray (Observations on the Heart,
&c. of the Foetus, p. 2) mentions a case in -which
the large coronary vein opened into the left auricle.

Sinus of the coronary vein. — This is always
described as a dilatation of the large coronary
vein, but I have found it decidedly muscular in
man and in several of the Mammalia, as the
dog, horse, ox, and sheep ; and it presents the
appearance of a muscular reservoir placed at
the termination of this vein, similar to the auri-
cles at the termination of the two cavae. This
sinus is placed in the posterior part of the
groove between the left auricle and ventricle,
adheres intimately to the outer surface of the
auricle, and communicates by one extremity
with the auricle, and by the other with the
large coronary vein. The commencement of
the dilatation is generally abrupt, and the first
appearance of the muscular fibres well defined.
I have seen it vary from two inches to only
half an inch in length. These muscular fibres
are generally circular ; part of them, however,
are oblique. Some of them belong exclusively
to the vein ; a great part appear to be connected
with the muscular fibres of the auricle. This
muscular sinus must serve to prevent regurgi-
tation along the coronary veins. I have also
generally found a distinct valve at the termina-
tion of the coronary vein in the sinus. This
valve resembles the valves found in the veins
of the extremities. It is generally single, some-
times it is double. I have also occasionally
found one or more single valves in the course
of the vein.* A distinct valve may also occa-
sionally be seen at the termination of the pos-
terior coronary vein in the sinus. Portal f
mentions that he has seen the coronary valve
situated in the interior of the vein a little from
its mouth. Thebesius and Morgagni have ob-
served valves placed in some of the smaller
veins where they terminate in the larger. The
valves of the coronary veins do not in general
prevent the passage of injections contrary to the
course of the blood along them.

Lymphatics of the heart. — The lymphatics
of the heart are divided into two sets — super-
ficial and deep; the superficial commencing
below the external serous membrane, and the
deep upon the internal membrane. They fol-
low the course of the coronary vessels. Some
of them pass directly into the thoracic duct,
and, according to Meckel, sometimes directly
into the subclavian or jugular veins. O there
pass into the lymphatic glands situated in front
of the arch of the aorta, while others pass into
the glands situated around the bifurcation of
the trachea, and a few also join the lymphatic
vessels of the lungs.

Pericardium. — The pericardium is a fibrous

Lecat (Mem. de 1'Acad. des Scien. 1738, p. 62)
found the coronary veins in a young child unite
themselves into a single trunk and enter the left
subclavian. It is probable that Soemmerring had
this case in view when he states, " Rarissime vena
haec in vena subclavia dextra finitur/' (de Corp.
hum. fab. torn. v. p. 340, 1800.) particularly as
Haller, (Element. Phys. torn. i. p. 375, 1757), in
quoting the case, has inadvertently substituted the
word dextra for sinistra.

* I have seen two or three pair of double valves
in the course of the coronary vein in the horse and
ass. These animals have noThebesian valve.

t Anatomic Mcdicale, torn. iii.

598

HEART.

bag surrounding the heart and origin of the
large bloodvessels, but without any direct
attachment to the heart itself, having its inner
surface lined by a serous membrane. It is
from this latter circumstance that it is generally
termed a fibro-serous membrane. It is placed
behind the cartilages of the second, third, fourth,
and fifth ribs of the left side and middle part
of the sternum. Posteriorly it rests upon the
parts contained in the posterior mediastinum ;
anteriorly it corresponds to the anterior medias-
tinum, and may be reached by perforating the
left side of the sternum, as has been proposed
in some cases of hydrops pericardii. The
pleurae adhere to its lateral and part of its
anterior surface by pretty close cellular tissue,
when the interposed fat is small in quantity.
The phrenic nerves with their small accom-
panying arteries pass down the thorax between
the pleurae and lateral surfaces of the pericar-
dium. Below, the fibrous part of the pericar-
dium adheres intimately to the upper surface
of the cordiform tendon of the diaphragm, and
is also connected by pretty dense cellular tissue
to the upper surface of the muscular fibres
running into the anterior part of the left lobe
of the tendon. It adheres more firmly to the
cordiform tendon at the edges, particularly
anteriorly, than at the centre. It is broader
below where it adheres to the upper surface of
the diaphragm, narrower above where it is
attached to the large vessels that pass in and
out from the heart. Upon these large vessels
the fibrous part of the pericardium is prolonged,
forming a kind of sheath, which gradually be-
comes thinner until it is confounded with the
cellular coat of the vessels. From the manner,
however, in which the vena cava inferior enters
the heart, it can have no fibrous sheath of this
kind. At the different points where the fibrous
coat becomes applied upon these vessels, and
where the cara inferior passes through the
cordiform tendon, the serous coat is reflected
upon the outer surface of the vessels, and
accompanies them back to the heart to cover
the outer surface of that organ. In this man-
ner the serous part of the pericardium is a shut
sac, the outer surface of which adheres to the
inner surface of the fibrous portion, and to the
outer surface of the heart. The inner surface,
like that of all the other serous membranes, is
unadherent, smooth, and shining, and is every-
where in contact with itself, and only contains
the small quantity of fluid which serves to
lubricate its interior. The serous portion of
the pericardium adheres intimately to the inner
surface of the fibrous. At that part, however,
where the serous leaves the fibrous to pass
back upon the surface of the large vessels,
there is a small triangular space left between
them. The serous membrane is reflected upon
and covers the outer surface of the aorta rather
more than two inches above its origin ; upon
the pulmonary artery about the same distance
and immediately before its bifurcation ; upon
the cava superior about an inch above its
entrance into the right auricle ; upon the cava
inferior shortly before it reaches the heart ; upon
the two right pulmonary veins soon after they

have emerged from the right lung; and upon
the left pulmonary veins shortly before they
enter the auricle. This serous membrane, in
passing upon the aorta and pulmonary arteries,
covers the anterior surfaces of both before it
passes round upon their posterior ; it then en-
velopes both arteries in the same sheath, so
that their opposed surfaces are only separated
from each other by a little cellular tissue. It
leaves part of the posterior surface of the cavae
and pulmonary veins uncovered, occasionally,
however, enveloping the whole or nearly the
whole, of the left pulmonary veins. It adheres
but loosely to the large bloodvessels, and firmly
to the outer surface of the auricles and ven-
tricles. The attachment of the fibrous part to
the cordiform tendon is very firm at the edges
and blended with the tendon, but becomes
looser towards the centre. Cloquet* describes
the serous membrane as lying in contact with
the upper surface of the cordiform tendon ; or,
in other words, he appears to consider the
fibrous part not to be prolonged over the upper
surface of the tendon, but to stop at its attached
margin. In most cases I have been able to
trace the fibrous part of the pericardium over
the upper surface of the cordiform tendon, but
almost always more or less diminished in thick-
ness. In some cases I was unable to detect
anything like a fibrous layer at this part. The
fibrous part of the pericardium is comparatively
thin, and is composed of tendinous fibres
interwoven together. It is not much larger
than sufficient to contain the heart when its
cavities are distended. This fact taken along
with the physical properties of the membrane,
not admitting of sudden dilatation, explains
how the sudden escape of a small quantity of
blood (8 oz. or sometimes less) into the interior
of the pericardium is sufficient to arrest the
heart's action.

The arteries of the pericardium are small and
come from various sources, from the bronchial,
cesophageal, phrenic, from the arteries of the
thymus gland, internal mammary, coronary
arteries, and the aorta itself. Its veins partly
terminate in the azygos, and partly accompany
the corresponding arteries to terminate in the
veins of the same name. Its lymphatics pass
to the glands placed around the cava superior.
The nerves can be traced into its texture.

Uses of the pericardium. — The pericardium
restrains within certain limits the irregular
movements of the heart. The inner serous
surface of the pericardium must also facilitate
its ordinary and healthy movements.

Relative position of the vessels within the
pericardium. — The pulmonary artery at its origin
overlaps the anterior surface of the aorta as it
springs from the left ventricle. (See^g. 276, s,
for the relative position of these vessels at their

* Traite d'Anatomie Descriptive, p. 633, trans-
lated by Knox. Cloquet does not state distinctly
that the fibrous part of the pericardium is not con-
tinued over the cordiform tendon, but this may be
inferred from the statement that the serous mem-
brane " is applied below, directly and in a very
close manner upon the aponeuroses of the dia-
phragm/'

HEART.

599

origin.) It then proceeds into the concavity of
the arch of the aorta, and as it is about to pass
through the fibrous coat of the pericardium, it
divides into its two branches, the right and
left. The left branch passes in front of the
descending portion of the arch of the aorta to
reach the left lung; the right branch passes
behind the ascending portion of the arch to
reach the right lung. In the foetus the pulmo-
nary artery divides into three branches, the
two we have just mentioned, and a third, the
ductus arteriosus, which unites the pulmonary
artery to the descending portion of the arch, —
in other words, after the aorta has given off' the
large branches to the head and superior extre-
mities. The descending cava, immediately
before it perforates the fibrous coat of the peri-
cardium, crosses the right branches close upon
the bifurcation of the trachea ; within the peri-
cardium it lies on the right side of the ascend-
ing portion of the arch of the aorta. The
inferior cava is seen perforating the cordiform
tendon of the diaphragm, and almost imme-
diately afterwards it enters the posterior and
inferior angle of the right auricle. The pul-
monary veins are placed inferior to the two
branches of the pulmonary artery. The two
right pulmonary veins pass behind the right
auricle to reach the left, which they enter near
the septum auriculorum.

Peculiarities of the fatal heart. — (For an
account of the developement of the heart and
large bloodvessels see OVUM.) The heart of
the foetus before the fourth month is placed
vertically, but towards that period the apex
begins to turn towards the left side. The
auricular part of the heart is considerably larger
in proportion than the ventricular. The relative
size of the heart to the body at birth differs
considerably from that of the foetus at an earlier
period of its developement. According to
JNJeckel the relative size of the heart to the
body about the second or third month of uterine
life is 1 to 50 ; at birth and for a few years
afterwards as 1 to 120. The greater size of the
heart of the foetus seems to depend principally
upon the greater thickness of the walls of its
cavities. The great disparity between the thick-
ness of the two sides so very apparent shortly
after birth does not exist in the earlier periods
of uterine life, though also generally sufficiently
well-marked in the fetus at the full time. This
is explained by the circumstance that the two
sides of the heart at this period have nearly
equal obstacles to overcome in propelling the
blood.* In the earlier stages of its deve-
lopement the infundibuliform portion of the
right ventricle is less prominent than at a later
period. The left ventricle is at first a little
larger than the right; at birth and fora short
while after they are equal. The two auricles
communicate with each other through the fora-

* In two foetuses, however, which I lately exa-
mined, and where I had positive evidence that
they had not yet reached the sixth month of utero-
gestation, the difference between the thickness of
the two ventricles of the heart was distinctly
marked.

men ovale.* This foramen is at its maximum
size about the sixth month.

Valve of the foramen ovale. — This valve,
which, however, can scarcely be called a valve,
as it is a provision for effecting the obliteration
of the foramen ovale at the time the child
assumes its independent existence, first makes
its appearance at the lower part of the foramen
about the third month, or, according to Senac
and Portal, about the second month. It is
formed by the inner membranes of the two
sides of the heart, containing some muscular
fibres between them, particularly at its lower
part. It is of a semilunar form ; its convex
edge adheres to a greater or less portion of the
margins of the valve as its growth is more or
less advanced; its concave margin, which is
free and loose, looks upwards and forwards.
This valve may be said to belong almost exclu-
sively to the left auricle, as it is attached to
that margin of the foramen .f Though this
valve is of sufficient size at birth to shut the
foramen, yet its concave or upper margin is
easily depressed so as to leave a considerable
interval between it and the upper margin
of the foramen. We will find, from the man-
ner in which the valve is attached to the left
margin of the foramen, that it is much more
easily depressed by a current passing from the
right auricle into the left than in the opposite
direction. In fact any force of this kind ap-
plied in the opposite direction would rather
tend to keep the valve applied to the upper
edge of the opening; a circumstance which
occurs after birth when the blood flows along
the pulmonary veins into the left auricle, and
which must materially assist in producing com-
plete obliteration of the foramen. The manner
in which the blood passes between the auricles
through the foramen ovale in the foetus was the
subject of a violent controversy in France at
the termination of the seventeenth and the
commencement of the eighteenth centuries. It
was first commenced between Meri on the one
side, who had proposed a new theory of the
foetal circulation by which the blood was made
to pass from the left auricle into the right, and
by Duverry and Fauvery on the opposite side,
who maintained the opinion of Harvey, and
which is now universally adopted, that it passes
from right to left. Many celebrated anatomists
and mathematicians attached themselves to the
opposite parties, and at last the controversy
extended itself to the neighbouring kingdoms. J

Eustachiun valve. — This valve, the appear-
ance and position of which have been already

* This opening is frequently termed trou de Botal
by the French writers though described by Galen.

f This explains how the depression (fossa ovalis),
marking in the adult the position of the valve,
should be better seen from the right than the left
auricle.

$ Those who may be anxious to acquaint them-
selves more fully with the nature of this contro-
versy and to examine the arguments adduced on
both sides may consult the Memoires de 1'Academie
for that period, and Senac's Traite de la Structure
du Cceur, torn. i. p. 369, and the Supplement in
torn. ii.

600

HEART.

pointed out in describing the interior of the
right auricle, is also intimately connected with
the peculiarities of foetal life. It was discovered
by Eustachius about the middle of the six-
teenth century, who contented himself by point-
ing out its position. Little attention was paid
to it until the commencement of the eighteenth
century, when it was more particularly brought
into notice by Boerhaave and Lancisi, who
published a new edition of the works and
plates of Eustachius, which had then become
very scarce. Lancisi supposed that this valve
prevented the blood of the superior cava from
falling with too much force upon the column
ascending by the cava inferior. Winslow,*
finding it only perfect in the foetal state, and
having cause to believe that its diminution kept
pace with the increase of the valve of the
foramen ovale, was led to adopt the opinion
that its presence had a special reference to that
state, and believed that it not only served to
break the current of the superior cava as stated
by Lancisi, but also opposed the regurgitation
of the blood of the auricle into the inferior
cava. In the absence of this valve he supposed
there would arise two inconveniences in the
fcetus — the imperfect intermixture of the con-
tained blood, and the regurgitation of the blood
of the umbilical vein into the placenta. Senacf
believed that the Eustachian valve can have no
effect in preventing the blood of the cava supe-
rior from falling upon the current ascending by
the cava inferior, and that it must direct a part
of the blood of the cava inferior through the
foramen ovale. SabatierJ more particularly
pointed out that from the position of this valve
passing from the anterior and left part of the
vena cava inferior to the left side of the foramen
ovale, and from the situation of the foramen
ovale at the inferior part of the auricle, the
blood of the cava inferior must be directed
through the foramen ovale; and further, from
the difference in the direction of the two cavae
themselves — the superior looking downwards,
forwards, and to the left side, while the inferior,
though it is also slightly directed to the left,
passes at the same time upwards and back-
wards, when combined with the upper thick
margin of the foramen ovale — it would neces-
sarily happen that the blood of the superior
cava must fill the right auricle.

In three injections of the fcetal circulation
which I performed, where arrangements were
made to imitate, as far as possibly could be
done, the manner in which the two currents
flow into the heart during the life of the foetus,
results were obtained confirmatory of the opi-
nion of Sabatier.§ This arrangement cannot
of course exist in the early months of uterine

* Mcmoires de 1'Acad. Roy., annee 1717.

t Op. cit. torn. i. p. 228.

j Traite complet d'Anatomie, torn. ii. p. 224.

$ Edinburgh Medical and Surgical Journal, 1835,
These injections are also confirmatory of one made
by Kilian, where the fluid thrown along the aorta
passed to the head and superior extremities, and
that along the pulmonary artery to the lower part
of the body.

life from the imperfect developement of the
heart itself, and in all probability part only of
the blood of the inferior cava is transmitted
through the foramen ovale into the left side of
the heart for a short time before birth. The
pulmonary veins appear to bring very little
blood to the left side of the heart until the time
approaches that the fcetus must necessarily
assume an independent existence. The circu-
latory apparatus becomes gradually prepared
for this change ; — the Eustachian valve begins
to shrink, the foramen ovale to diminish in size,
and a greater quantity of blood is transmitted
through the lungs. Billard* has ascertained
from the examination of the bodies of a great
number of infants who died within a few days
after birth, that the foramen ovale and the other
circulatory passages peculiar to the fcetus are
generally shut about the eighth day after birth.
In nineteen infants who had lived only one
day the foramen ovale was completely open in
fourteen ; in two it had commenced to become
obliterated, in the remaining two it was com-
pletely shut. On the subsequent days the
number of those with the foramen shut con-
tinued to increase; and in twenty examined,
who had died on the eighth day, five only had
the foramen open.

PHYSIOLOGY OF THE HEART.
Mode of action of the valves of the heart. —
While the blood is rushing through the auri-
culo-ventricular openings during the contrac-
tion of the auricles, the lips of the mitral and
tricuspid valves are separated from each other
and thrown outwards from the axis of the
opening, and the larger lip of both is at this
time carried towards the arterial orifices. It
has generally been supposed that the mitral and
tricuspid valves are, during the systole of the
ventricles, passively floated up towards, and
obstruct the auriculo-ventricular orifices so as
to prevent the free regurgitation of the blood
into the auricles ; and that the use of the cordae
tendinese is merely to limit the movements of
the valves, — to permit them to be raised suffi-
ciently to close the orifices, but at the same
time to provide against the otherwise unavoid-
ably fatal consequences that would result from
these unresisting valves being carried through
into the auricles by the current of blood. Mayo,
Bouillaud, and others have, however, main-
tained that the lips of these valves are not
approximated in the mechanical manner just
stated, but by the contraction of the musculi
papillares of which the cordae tendinese are the
proper tendons. As the musculi papillares
contract along with the other fibres of the ven-
tricles, the lips of the valves are drawn towards
the axis of the opening, and are closely applied
to each other, forming a kind of cone, the apex
of which projects downwards into the ven-
tricles. It is from the adoption of these views
that Bouillaud proposes to call these musculi
papillares, the tensor, elevator, or adductor
muscles of the valves. That the lips of the

* Traite des Maladies des Enfans nouveau-nes,
&c., p. 557, 1828.

HEART.

601

valves are approximated in this manner appears
to me to be the much move probable opinion;
for when we examine the uniform position and
course of the musculi papillares and chordae
tendineae, more particularly those of the left
ventricle ; that the chordae tendineae pass from
each musculus papillaris to both lips of the
mitral valve, occasionally crossing each other;
and that the posterior or smaller lip, though
it may be drawn inwards so as to meet the
larger and more moveable, is so bound down
as to be scarcely capable in most cases of being
floated up on a level with the orifice; and
further, when we also remember that the mus-
culi papillares contract at the same time with
the other fibres of the heart, we can scarcely
resist coming to this conclusion. Besides, if
the lips of the valves were floated up to the
orifice, a greater quantity of blood would regur-
gitate into the auricles during the systole of the
ventricle than in all likelihood takes place;
for as the lips of the valve must be widely
separated from each other when the systole
commences, it is evident that a less quantity
of blood must have passed through the orifice
before the lips are sufficiently approximated to
obstruct its further passage when these are
assisted by an active force, than when they are
merely passively brought together by the cur-
rent of blood passing in that direction. It has,
however, been supposed that the musculi
papillares do not contract with the other fibres
of the ventricles. lialler states* that on laying
open the heart he has seen the muscles of the
valves contract during the systole of the heart.
It may be objected to this experiment that the
unusual stimulus applied to the heart in cutting
its fibres across may have deranged the usual
order of its contractions. I have repeatedly
opened the heart in rabbits and waited until its
contractions had ceased, and on renewing its
movements by irritating the inner surface at a
distance from the cut edges, 1 have observed
that the columns carneae acted simultaneously
with the other muscular fibres of the heart.f I
was also satisfied that the musculi papillares
were proportionally more shortened during their
contraction than the heart itself taken as a
whole, which is nothing more than what we
would expect when we remember that the fibres
of the musculi papillares are so far free and
run longitudinally, while by far the greater part
of the other fibres run in a spiral manner.

Haller, in relating his observations on the
contraction of the musculi papillares, makes
another statement, which, however, is decidedly
adverse to this opinion. The chordae tendineae
appeared to him to be relaxed during the con-
traction of the musculi papillares.

It is difficult to make satisfactory observa-
tions upon the effects of the contractions of the

* Elementa Physiolog. torn. i. p. 390. Sur le
Mouvement du sang, p. 129. Memoires sur la
Nature sensible, torn. i. p. 379.

t [The observations of the London Committee
appointed by the British Association to examine
into the motions and sounds of the heart confirmed
this view of the simultaneity of contraction of the
columnar earner and ventricular fibres. — ED.]

musculi papillares upon the tension of the
chordae tendineae. In several animals upon
which we attempted to ascertain this, it was
only when the heart was acting languidly that
we could observe what was likely to be the
effect of the contraction of the musculi papil-
lares on the chordae tendineae when they were
placed as far as possible in their natural rela-
tion to each other. We could never observe
that they contracted sufficiently to move the
valves, but they certainly rendered some of the
chordae tendineae more tense. When, however,
we take into account, that in an experiment of
this kind, the valves are not thrown out widely
from the orifices of the auriculo-ventricular
orifices, the ventricle is not distended with
blood, the chordae tendineae consequently not
put so far on the stretch as occurs at the com-
mencement of the systole, and that the con-
tractions of the musculi papillares are languid,
we can easily perceive how, in the natural
systole of the heart, these contractions of the
musculi papillares should be sufficient to move
the valves inwards, though not to such an extent
as to apply them closely to each other. The con-
traction of these musculi papillares apparently
sets the valves in motion, and they are subse-
quently applied to each other by the currents
of blood. It may be supposed that if the con-
traction of these musculi papillares can render
the chordae tendineae sufficiently tense to move
the valves, this would prevent the subsequent
elevation of them to obstruct the auriculo-
ventricular opening. We believe, however,
that it is only at the commencement of the
systole that they are sufficiently tense to move
the valves, for as the contraction proceeds the
capacity of the heart is so much diminished,
both in its transverse and longitudinal dimen-
sions, that they become relaxed. Besides, if
we could suppose that these musculi papillares
are capable of contracting through a sufficient
space to draw the valves together, this would
be all that is necessary to prevent the regurgita-
tion of the blood through the auriculo-ventri-
cular opening.*

So convinced, indeed, were the older anato-
mists and physiologists that the chordae tendineae
are relaxed during the systole of the heart, and
of the necessity of an accompanying diminution
of the length of the ventricles themselves to
effect this, that this argumentadduced by Bassuel
appears to have been principally instrumental
in deciding the once keenly controverted ques-
tion whether or not the heart was elongated
during its contraction .f

* All these experiments upon the action of the
columns carneae were finished and the article
forwarded to London about the middle of June,
1836.

t Mr. T. W. King in an elaborate essay (Guy's
Hospital Reports, No. iv. April 1837,) has pointed
out what he conceives to be a tf safety-valve func-
tion in the right ventricle of the human heart."
This view is founded upon the fact which he be-
lieves that he has ascertained, " that the tricuspid
valve, naturally weak and imperfect, closes less
and less accurately, according to the increasing
degrees of the ventricular distention." From this
he is " convinced that, in all cases in which the

602

HEART.

It may be supposed that the relative size of
the auriculo-ventricular orifices to the length of
the lips of the valves would not admit of their
apices being brought together in the form of a
cone as described, but it must be remembered
that from the course of the muscular fibres in
the immediate neighbourhood of those open-
ings, their areas must be diminished during
the systole of the heart. There is at least one
thing certain connected with the action of these
valves, viz. that the contraction of the musculi
papiilares can never cause the valves to strike
the inner surface of the ventricle and produce
a sound as has been supposed.

The manner in which the semilunar valves
at the origin of the aorta and pulmonary artery
perform their office is entirely mechanical and
easily understood. During the systole of the
heart they are thrown outwards from the axes
of these vessels ; but during its diastole, when
part of the blood driven into the artery would
fall back into the ventricles, these valves are
thrown inwards and obstruct completely the
whole calibre of the arteries. In all probability
the sinuses of Valsalva placed behind these
valves contain a certain quantity of blood even
during the systole of the heart, and this re-
acting upon the valves through the agency of
the elasticity of the arteries brought into opera-
tion at the termination of the systole, materially
assists in producing the more rapid arid certain
action of the valves.

Movements of the heart. — The heart is a
muscle of involuntary motion, being, for the
wisest of purposes, placed beyond the direct
control of volition. The case of Colonel
Townshend* is of too obscure a nature to
entitle us to found upon it an opposite doc-
trine, more particularly as it is at direct variance
with every other fact or observation.

The movements of the heart, when the body
is at rest or in a state of health, proceed with-
out our consciousness. In certain cases of
disease they are attended by uneasy feelings,
but they are never at any time or under any
circumstances dependent upon sensation for
their continuance.

It is not so easy a matter as may at first be
imagined to ascertain the order of succession
in which the different cavities of the heart con-
tract and dilate, and the different circum-
stances which attend these movements, even
by experiments on living animals, more par-
ticularly the warm-blooded animals ; for if the
heart when exposed is acting vigorously and
rapidly, every one who has examined for him-
self must have felt the exceeding difficulty of
following and analysing these movements by

right ventricle is, in any material degree, tempo-
rarily distended or permanently dilated, the heart
and lungs are relieved by a considerable reflux of
the ventricle's contents into the auricle and sys-
temic veins." In experiments upon the lower
animals I have repeatedly seen the right ventricle,
when gorged with blood and acting feebly, empty
itself through an opening in the jugular vein.
Edinb. Med. and Surg. Journ. 1836.

* Cheyue's English Malady, p. 307. 1734,
London.

the eye. If, on the other hand, the animal
has become debilitated and the movements of
the heart languid, these are apt to deviate from
their natural order, and to be performed in an
irregular and unnatural manner.* It is in this
way that we can account not only for the dis-
crepant statements of the older observers, but
also for the very frequent announcement of
new views on this subject which appear in the
medical periodicals of our own day. As we
will find that many of these theories connected
with the physiological actions of the heart even
in the present day, have been founded upon
false notions of the normal anatomy and na-
tural movements of the organ, and only require
a reference to these for their full and satis-
factory refutation, it will be necessary that we
attend particularly to the manner in which
these different contractions and relaxations suc-
ceed each other, and the visible phenomena
by which they are accompanied, as observed
by the most accurate experimenters.

When the heart of a living animal is ex-
posed and the organ is acting in a natural
manner, the auricles are observed to become
distended with blood, then to contract rapidly
and simultaneously, and propel part of it into
the ventricles; this is accompanied with a
corresponding enlargement of the ventricles,
which is immediately followed by their simul-
taneous contraction and the propulsion of their
blood along the large arteries : then follows a
pause, during which the auricles become gra-
dually distended by the blood flowing along
the veins. When the auricles are filled, they
again contract, and the same train of pheno-
mena just described occur in uniform succes-
sion.

Systole and diastole of the auricles. — The
contraction or systole of the auricles is pre-
ceded by their relaxation or diastole. During
the diastole the auricles become distended with
the blood flowing along the veins. The com-
mencement of the diastole occurs during the
contraction of the ventricles; the latter part
corresponds to the pause in the heart's action,
and to the interval between the recurrence of
the sounds of the heart, and is more or less
long in proportion as the blood flows more or
less rapidly along the veins.

The systole of the auricles is performed with
great rapidity when the action of the heart is
still vigorous, and appears to be effected by
the simultaneous contraction of all its fibres.
The terminations of the cavae and pulmonary
veins are seen to contract simultaneously with
the fibres of the auricles, but sometimes they
are seen to contract previous to the auricles,
into which they expel their blood. In the cold-
blooded animals this contraction of the ter-
minations of the large veins extends over a
greater surface, and is visible in the venae he-

* The illustrious Harvey thus describes the dif-
ficulties which he experienced in his first attempts
to analyse the movements of the heart: " ita ut
modo hinc systolem, illinc diastolem, modo e con-
tra, modo varies, modo confusos fieri motus me
cxistimarem cernere."

HEART.

603

paticae.* Judging from the number of mus-
cular fibres which surround the termination of
the pulmonary veins in the human species,
we would expect these contractions to occur to
a greater extent in these veins than in the cavae.
These contractions in the veins must assist the
vis (i tergo, or the force with which the column
of blood flows along the veins towards the
heart, in limiting the regurgitation along these
during the contraction of the auricles. This
regurgitation along the veins appears to be to
a small extent only when the circulation is pro-
ceeding in a natural manner, but becomes con-
siderable where there is any impediment to the
free passage of the blood into the ventricles,
and when the blood becomes stagnated in the
veins. When the actions of the heart are en-
feebled, the contractions of the auricles are
slower, and may become more or less vermi-
cular, as I have myself occasionally observed.
Two or more contractions of the auricle may
also now be necessary before the languid ven-
tricle can be excited to contraction. When
the action of the heart is still more enfeebled,
particular portions only of the auricles con-
tinue to contract. According to the obser-
vations of Harvey, Lower, Senac, Haller, and
others, the contractions of the auricles are per-
formed with considerable force.

Harvey states that he has observed that if the
finger is applied to the ventricles in those cases
where the action of the auricles continues after
the contractions of the ventricles have ceased,
a distinct beat is felt in the ventricle at each
stroke of the auricle ; and Senac, in quoting
this, adds (evidently from his own observation)
that it is similar to the pulse in the arteries.
Senac also states that if an opening be made
into the apex of the heart under those circum-
stances, a jet of blood rushes through it at
each stroke of the auricle. He, however,
admits that the contraction of the auricles in
these cases is not sufficient to dilate sensibly
the walls of the ventricles, but, of course, very
considerable allowance ought to be made for
the enfeebled state of the auricles at this stage
of the experiment. f In the experiments of
Dr. Hope, Mr. Carlisle, M. Bouillaud, and
the Dublin Committee for investigating the
cause of the sounds of the heart, the contrac-
tion of the auricles appeared to be compara-
tively trifling, and was most apparent in the
appendices. From my own observations upon
rabbits and dogs I am convinced that the au-
ricles contract considerably more when the
movements of the heart are proceeding in a
natural manner, than some of these last expe-
riments would lead us to believe, and that this
contraction is not confined to the appendix,

* The contractions of the different parts of the
heart in cold-blooded animals have been observed
to occur in the following order : first, the termin-
ation of the large veins, then the auricles, then
the ventricles, and, lastly, the bulb of the aorta.

f I have convinced myself of the accuracy of
these statements of Harvey and Senac in expe-
riments upon dogs opened soon after they had been
deprived of sensation.

but extends over the whole auricle. When
the circulation through the lungs becomes im-
peded, the right ventricle is then unable to
empty itself, and the auricle of the same side
(and this is the one that is most generally ob-
served in such experiments) is consequently
impeded in its movements. The auricles do
not certainly exert the force or contract to the
extent which some have stated, do not ex-
pel the whole of their contents, and their
diastole is comparatively feeble; but that none
of the muscular fibres of the auricles are pas-
sive, but exert a force proportionate to their
strength, we have evidence both from expe-
riment and the effects of disease. In some
of those cases where an impediment to the
passage of the blood from the auricle to the
ventricle exists, all the muscular fibres of the
auricles become much increased in thickness
and in strength. As the left auricle has natu-
rally greater difficulties to overcome iu pro-
pelling its blood than the right, so we find that
the left auricle is considerably more muscular
than the right.* The appendix from its being
loose, and supplied by a band of longitudinal
fibres drawing it backwards, must enjoy a freer
motion than the other parts of the auricle.

Systole and diastole of the ventricles. —
When the heart is acting Vigorously, the con-
traction of the ventricles succeeds immediately
upon that of the auricles, so that they some-
times appear continuous ; or, in other words,
the sudden distention of the ventricles by the
blood propelled into them during the systole
of the auricles is rapidly followed by the con-
traction of the ventricles. The systole of the
ventricles must occur during the diastole of the
auricles. As we are only sensible of the sys-
tole of the ventricles from external examination
during life, the expression systole of the heart
is always employed as synonymous with the
systole of the ventricles. WThen the action of
the heart is a little less active, an apparent in-
terval is observable between the completion of
the contraction of the auricles and the com-
mencement of the contraction of the ventricles,
— the irritability of the ventricles being at this
time somewhat impaired, their contraction does
not so quickly follow their sudden distention.
The ventricles during their systole are dimi-
nished in all their dimensions; the apex is
drawn upwards to the base and tilted forwards
so as to strike the parietes of the thorax be-
tween the cartilages of the fifth and sixth ribs.f

* In the case mentioned by Allan Burns, where
an ossific deposit covered the whole surface of the
ventricles, so as to entirely, or nearly entirely, pre-
vent their action, the auricles must have per-
formed part of their functions for some time before
death. In one of the experiments of Dr. Wil-
liams, of London, upon asses, he observed the
circulation along the arteries continue although
the ventricles were quiescent, and the auricles
alone contracted.

t " Dr. C. J. B. Williams has, in a lecture lately
published in the Medical Gazette (July 28, 1838,
p. 692,) pointed out that, during a deep inspira-
tion, the ribs are elevated without raising the heart
in the same degree, and the impulse may be felt

604

HEART.

The parietes of the ventricles at this time are
firm and resisting, and present some rugae on
their outer surface. Haller* states that though
the principal movement of the ventricles du-
ring their systole is from the apex upwards,
yet he has sometimes observed a slight but dis-
tinct movement from the base downwards. The
contraction of the ventricles is performed with
great force, and, when vigorous, appears to be
accomplished by the simultaneous action of all
its fibres ; but at other times, when it has be-
come enfeebled, it has been observed to com-
mence at the apex and extend itself upwards.

The diastole of the ventricles consists of two
distinct stages. The first, which immediately
follows its systole, is sudden, the apex being
pushed downwards and apparently passing
deeper into the chest, and is occasioned by the
return of the heart to its state of rest. The
second is also sudden, and attended by a rapid
but not very extensive enlargement of the heart
in all its dimensions. The parietes of the
heart are soft and ftaccid, and their external
surface smooth during their diastole. The
diastole of the heart is performed with con-
siderable force, so thatPechlin, Perrault, Ham-
berger, and others long ago maintained that
this equally with the systole is the result of a
vital action. This opinion was again revived
by Bichat, Dumas, and their followers, and is
still introduced by some into the discussions
upon the movements of the heart. Before
we can admit an opinion of this kind, it
would be necessary that very strong evidence
be adduced in its favour, as it is at perfect
variance with all that we know of the arrange-
ment of the fibres of the heart, and of the
laws of muscular contractility.f

OesterreicherJ has performed the following
experiment, which appears- nearly decisive on
this point. When a body is placed on the
heart of a frog heavy enough to press it flat,
but sufficiently small to allow the heart to be
observed, it will be seen that the body will be
lifted during the contraction of the heart, but
that during its extension it will remain flat.
From this it appears that the extension of the
heart after the contraction is not a muscular
act. The diastole of the heart depends then
upon two circumstances. 1st, Upon the na-
tural elasticity of the organ, which it possesses
in common with every other muscle, and by
which it instantly resumes its state of rest as
soon as its contraction has ceased. This, which
is usually termed the relaxation of a muscle in
whatever part of the body it occurs, must be
expected to be more energetic in the heart than

below the sixth rib. On the other hand, when the
ribs are depressed, as during a deep expiration,
the apex of the heart may be felt beating between
the fourth and fifth ribs/'

* El. Phys. torn. i. p. 400.

t Scharschmid supposed that certain pretended
longitudinal fibres^by shortening the heart enlarged
its cavities, while the transverse fibres by contract-
ing separately diminish its capacity.

J Muller's Handbuch dcr Physiologic des men-
schen, Erster Band, p. 163.

in the muscles of voluntary motion, as from
the arrangement of its fibres a great part must
be more strongly compressed. This occurs
during the first of the two stages into which
we divided the diastole. 2d, Upon its sudden
distention during the contraction of the auricles,
when we have every reason to believe that the
ventricles are completely passive. This con-
stitutes the second stage of the diastole. The
blood must then pass from the auricles into
the ventricles during each diastole at two dis-
tinct periods of time, corresponding to these
two stages. During the first stage, or the re-
laxation of the ventricles, it flows from the
auricles to fill up the vacuum produced in their
interior; while, during the second stage, it is
forcibly propelled by the auricles. It would
be difficult to estimate the relative proportion
of these two quantities of blood. Those who
suppose that the contraction of the auricles is
feeble must consequently believe that most of
the blood passes from the auricles into the ven-
tricles during the first stage.

It has been long disputed whether or not the
ventricles empty themselves completely during
each systole. It is very difficult to perceive
anything like correct data upon this point in
the warm-blooded animals with opaque hearts;
but reasoning from analogy, from what we see
in the cold-blooded animals whose hearts be-
come quite pale during each systole, (not, as
Harvey supposed, from the blood being pressed
out of its parietes, but from the blood in its
cavity, seen through its transparent sides, being
almost entirely expelled during its systole,)
we would be inclined to believe that little
blood remained after each systole in the active
state of the organ, while we can easily sup-
pose that a greater or less quantity is left after
each contraction when the organ is less vi-
gorous.

It was the subject of a violent dispute at the
commencement of the last century between the
Montpellier and Parisian anatomists and phy-
siologists, whether or not the heart became
shortened or elongated during its contraction.
In all the warm-blooded animals at least it
undoubtedly becomes shortened.* We may at
the same time state that the obliteration of the
cavity of the ventricle depends much more upon
the approximation of its sides than the drawing
up of the apex.

Impulse of the heart. — It has been at various
times, and still is by some late and modern
experimenters,! maintained that the apex of
the heart strikes the parietes of the thorax during

* The authority of Harvey has been quoted in
favour of the opinion that the heart becomes elon-
gated during its contraction, and certainly in one
part of his work it is distinctly stated, that it is so
to a certain extent : " Undique contrahi magis
vero secundum latera ; ita uti minores magnitu-
dinis et lonyiusculum , et collectum appareat."

f Pigeaux, Stokes, Burdach, and Beau. Dr.
Corrigan has, much to his credit, publicly re-
nounced his previously published opinions on this
question, after more accurate observations had con-
vinced him of his error.

HEART.

605

its diastole, and not during its systole. This
is in reality what we would a priori expect,
for it certainly does at first appear somewhat
paradoxical that the heart should strike the
parietes of the chest when the apex is ap-
proximated to the base. The concurrent tes-
timony of the most accurate observers has,
however, fully established the correctness of
the fact. Harvey observed it in the human
body when the heart had been exposed from
the effects of disease.* One of the principal
arguments adduced in support of this opinion
by these authors was drawn from the fact that
the pulse at the wrist is not synchronous with
the impulse against the chest, an opinion
which had been pretty generally maintained
since the time of Aristotle. It is difficult to
be convinced of this when the pulse is quick ;
but when it is slow, and in certain cases of
disease of the heart, it can generally be satis-
factorily ascertained. So far then they are right,
but in the next and most important step of the
argument they fall into a decided error; for
they proceed upon the supposition that the
pulse is synchronous in all the arteries of the
body at the same time, and consequently the
impulse of the heart at the chest cannot be
synchronous with the flow of blood along the
arteries, or, in other words, with the systole
of the heart. In opposition to this opinion,
Dr. Youngf had previously shown upon the
principles of hydraulics that the pulse along
the arteries must be progressive, yet in general
so rapid as to appear to arrive at the extremities
of the body without the intervention of any
perceptible interval of time. And when the
attention of medical men was turned to this
subject, various observers soon ascertained by
repeated experiments that the pulse could
be felt in favourable cases to pass along the
arteries in a progressive manner, — that the
pulse in the large arteries at the root of the
neck and impulse at the chest are synchronous
or nearly so, that both precede that at the wrist,
and more distinctly still that of the dorsal
artery of the foot.J

Various attempts have been made to explain

* " Simul cordis ipsius motum observavimus,
nempe illud in diastole introrsiim subduci et
retrain ; in systole vero emergere denuo et protrudi
fierique in corde systolem quo tempore diastole in
carpo percipiebatur : atque proprium cordis motum
et functionem esse systolem : denique cor tune
pectus fierique et prominulum esse cum erigitur
sursum." As quoted by Shebeare, Pract. of Phy-
sic, vol. i. p. 195.

t Phil. Trans. 1809.

j It is interesting and curious, as shewing the
revolution of opinions, to compare the strict simi-
larity of the arguments adduced by the modern
supporters of this doctrine with those maintained
by Shebeare in 1755. (Practice of Physic, vol. i.
p. 193.) " This, however plausible it may ap-
pear, cannot be the true cause of it (impulse of
the heart), because then this stroke must be during
the systole of the ventricles, which would be syn-
chronous with the diastole of the arteries ; whereas
the beating of the heart precedes the dilatation of
the arteries, and thence this stroke must be made
during the diastole of the ventricles : thus the
diastole or distention of the heart is the cause of
the beating against the ribs."

in what manner the apex of the heart is made
to impinge against the parietes of the chest by
those who maintain that it occurs during the
systole of the ventricles. Senac supposed that
this was principally effected by the curvature
of the two large arteries, but principally of the
aorta, which arise from the ventricles; for at
each stroke of the ventricles when an addi-
tional quantity of blood is driven into the large
arteries, as they are curved they make an at-
tempt to straighten themselves; and as this
takes place to a slight extent, the heart, which
is attached to their extremities, ought to be
displaced, and its apex, which describes the
arc of a circle greater than the other parts of
the heart, is thus made to impinge against the
walls of the chest. He also believed that the
distentiou of the left auricle with blood during
its diastole has also, from its position between
the spine and base of the heart, the effect of
pushing the heart forwards ; and this occurring
at the same time with the attempt which the
curved arteries make to straighten themselves,
it thus acts as a second or subsidiary cause in
tilting the heart forwards.* Though this sup-
posed effect of the curvature of the large
arteries has been a favourite explanation with
many of the impulse of the heart against the
chest, yet it really appears to have little, if any,
influence in producing this. Shebeare,f and,
more lately, Dr. Corrigan,t have shown that
the direction of the curvature of the large ar-
teries is such, that if any effect of this kind is
produced, the heart would not be earned to
the left side, but in the direction of the curve,
which is exactly in the opposite direction.
Besides the tilting forwards of the heart has
been observed though no blood was passing
along the large vessels at the time, and the
same thing takes place after the large vessels
have been cut through and the heart removed
from the body.§ Haller and others have sup-
posed that the secondary cause assigned by
Senac,— viz. the sudden distention with blood
of the left sinus venosus which lies impacted
between the spine and left ventricle, — is the
principal if not the sole cause by which the
heart is pushed forwards against the ribs. In
confirmation of this opinion Haller states ||
that if we inflate the left auricle after having
opened the chest, we see the point of the heart
approach with vivacity the region of the mam-
ma. As we cannot, however, under these cir-
cumstances distend the auricle without also
distending the corresponding ventricle, this
movement of the heart depends more upon the
sudden inflation of the ventricle than upon any

* Op. cit. torn. i. p. 356. The cause of the tilt-
ing motion of the heart was also, at a later period,
attributed to the curvature of the aorta and to this
exclusively by Dr. W. Hunter. Note in John Hun-
ter's Treatise on Inflammation, p. 146, 1794.

t Op. cit. p. 195.

t Dublin Med. Trans, vol. i. p. 154.

$ Dr. Carson (Inquiry into the Causes of the
Motion of the Blood, p. 183,) maintains that no
proof can be adduced that the curvature of the
aorta is rendered more straight during the systole
of the heart.

|| Sur la Mouvement du Sang, p. 124.

606

HEART.

distention of the auricle, as any one may easily
satisfy himself by repeating the experiment.
Besides, the distention of the auricles by the
blood flowing along the veins is too gradual for
this sudden and rapid impulse of the heart ;
nay more, — the impulse may be observed when
no blood is flowing into the auricles. Sabatier*
believed that this impulse depends upon two
causes, — 1st, principally upon the distention of
the auricles, more particularly the left ; and,
2dly, upon the curvature of the large arteries.
Apparently, however, perceiving the necessity
of there being a sudden distention of the auri-
cles to produce this, he supposed that this was
effected by the auriculo-ventricular valves. He
argued that, as these valves during the diastole
of the heart form a cone stretching from the
base towards the point of the ventricle, which
is full of blood when the systole commences,
when the valves are carried upwards to ob-
struct the auriculo-ventricular orifices, this
blood is pushed before them into the auricles,
producing a reflux into the auricles, which,
with the blood flowing along the cavae and pul-
monary veins, causes a sudden distention of the
auricles, which pushes the ventricle forwards.f
Meckel appears to have adopted the opinions
of Sabatier. We need not repeat our objec-
tions to this explanation. Dr. Alison, per-
ceiving the insufficiency of all these explana-
tions, has for a considerable time past sug-
gested in his lectures, that this might be ex-
plained by the arrangement of the fibres,
•" more particularly by the irregular cone which
they form, being flattened posteriorly, and by
ihe consequent greater mass of fibres on the
anterior surface." More lately Mr. Carlisle J
has also attempted to explain this by the greater
length of the anterior fibres of the heart than
of the posterior. As the shape of the ventricles
is an oblique cone, and as they have their long-
est sides in front, he argues, " that it is a
law of muscular contraction that fibres are
shortened during their contraction in proportion
to their length when relaxed. For instance, if
a fibre one inch long lose by contraction one-
fourth of its length, or one quarter of an inch, a
fibre two inches in length will lose one inch by
contractions of equal intensity. The apex then
does not approach the base in the line of the
axis of the ventricles, but is drawn more to the
side of the longer fibres, that is, towards the
front, thus producing the tilting forwards."
We believe that it may be proved on mechani-
cal principles, that though the anterior and left
surfaces of the ventricles are considerably longer
than those on the posterior and right, yet during
their contraction, when they are drawn towards
their fixed attachments, if the fibres are of
equal thickness, the apex will be drawn up
nearly in the diagonal of the two forces, and
that if any tilting upwards of the apex take
place, this will be only to a small extent, and

l * Traite complet d'Anatonaie, torn. ii. p. 230.

t Dr. Bostock has failed of his usual accuracy
in detailing the opinion of Sabatier on this ques-
tion.

| Transactions of British Scientific Association,
vol. iii. Dublin Journal of Medical Science, vol. iv.

be quite insufficient to account for the impulse
felt at the chest. We must therefore look to
some other circumstances besides a mere diffe-
rence in length of the two surfaces to account
for this. Mr. Alderson* has ingeniously at-
tempted to apply the law of action and reaction
between bodies, — one of considerable import-
ance in mechanical philosophy, and upon which
Barker's centrifugal mill has been constructed.
Unfortunately, however, for this explanation,
the axes of the large arteries and the direction
in which the apex is tilted do not by any means
accord. Dr. Hope's supposition that " the re-
tropulsion of the auricular valves" may assist
in producing this impulse, " as these act on a
column of blood which offers a greater resist-
ance than the weight of the heart, the action is
reflected on the organ itself and impels it for-
wards," is, on the other hand, completely op-
posed to the law that action and reaction are
the same. As well may a man attempt to pro-
pel a boat by standing in the stern, and push
with an oar against the prow. Dr. Filhos attri-
buted the impulse to the spiral turns of the
fibres at the apex of the heart attempting to
straighten themselves during their contraction,
and so raise themselves suddenly and throw
themselves forwards. The objections to this
explanation are so palpable that they must
occur to every one. Since the tilting of the
apex of the heart forwards is observed after the
blood has ceased to flow through its cavities, it
is obvious that we must look for the cause of
this in the arrangement of the muscular fibres
themselves, though it may be difficult to point
out that particular arrangement. It appears to
me that the distribution of some of the strong
bands of fibres, the course of which I have
already described when treating of the muscu-
lar tissue of the heart, may satisfactorily account
for it. We there pointed out that several strong
bands of fibres arise from the base of the septum
between the ventricles, pass downwards and
form part of the septum, then emerge from the
anterior longitudinal groove (fig. 274, d), and
wind round in a spiral manner to form both the
anterior and posterior part of the lower portion
of the heart. On entering the apices of the
ventricles, (principally the left,) the fibres are
scattered over their inner surfaces, and while a
great number of them go directly to be inserted
into the tendinous rings, others form part of the
columnse carnese. We have thus strong bands
of fibres attached by one extremity (their septal
extremity) to the base of the ventricles at a
point pretty far posterior, while at the other ex-
tremity many of the fibres are loose, or at least
only attached to the tendinous rings through
the media of the chordae tendineae and valves,
which must admit of a certain degree of con-
traction of these fibres before they become tense.
At each systole of the heart when these fibres
act, it is evident that the tendinous rings must
form the fixed points towards which all these
fibres contract ; and since they are by one ex-
tremity all closely and directly connected to a

* Quarterly Journal of Science. &c. vol. xviii.
p. 223.

HEART.

607

fixed attachment, viz. the tendinous rings, white
by their other extremity part only are directly
attached to the tendinous rings, the other part
being loose, or at least only connected to the
tendinous rings through the lax chordae tendi-
neae and valves, it must follow that the force
with which the contraction takes place towards
the septal extremity must preponderate over
the other. If these bands of fibres had been as
closely connected to the tendinous rings at the
one extremity as at the other, then the force of
the contraction towards both would have been
equal ; but since this is not the case, the apex
must be carried forwards at the same time that
it is drawn upwards towards the base. This
forward motion may also probably be assisted
by another arrangement of the same fibres
which we have been describing; for some of
these muscular bands are attached by their
inner extremity to the anterior part of the left
auriculo-tendinous ring, so as to form loops, the
greater part of which lie more in front than be-
hind the axis of the heart, and may have a ten-
dency, when in a state of contraction, to draw
the apex forwards and upwards. Now when
we remember that by this elevation of the apex
forwards, the heart, before placed obliquely,
now becomes more horizontal, and conse-
quently more approximated to the walls of the
chest, — the more particularly as the transverse
diameter of the chest diminishes rapidly as we
proceed from below upwards, we believe that
we have here sufficient to account for this im-
pulse against the chest. As the proximity of
the apex of the heart to the chest is affected by
the position of the body, as we have already
pointed out, this circumstance ought to be at-
tended to in judging of the strength of the im-
pulse of the heart.

What parts of the heart most irritable. — The
inner surface of the heart is considerably more
irritable than the outer. In experiments, when
the heart has become quiescent, and refuses to
obey a stimulus applied to the outer surface, it
frequently contracts readily for a short time
after this when air is introduced into its cavi-
ties, or when any other stimulant is applied to
its inner surface. After death the different
cavities of the heart generally lose their contrac-
tility in the following order, the left ventricle,
the right ventricle, the left auricle, and last of
all the right auricle.* And as the heart is gene-
rally the part of the body which shews the latest
evidences of contractility, the right auricle has
long received the name of ultimum moriens.
Haller supposed that the greater persistence of
contractility in the right side of the heart over
the left might depend on the circumstance that
the right side of the heart generally contains a
greater or less quantity of blood after death,
while the left side is generally empty. In this

* There is occasionally considerable variety ob-
served in the order in which the different cavities
lose their contractility after death. The left ven-
tricle has been seen to contract after the right auri-
cle ; and Haller has observed in experiments upon
cats the irritability of the left auricle first cease.
In experiments upon dogs I have seen the ventri-
cles contract after the auricles had ceased to do so.

manner the inner surfece of the right side of the
heart is subject after death to the presence of a
stimulant from which the left side is compara-
tively free. He put this opinion to the test by
performing repeatedly the following experi-
ment.* He emptied the right side of the heart
by the section of the pulmonary artery and
venae cavae, having previously retained the
blood of the left side by passing a ligature
around the aorta. The experiment succeeded
many times : the right auricle remained per-
fectly immoveable, and the only motion which
the right side retained arose from the connexion
of its fibres with those of the left ventricle.
The left auricle retained its movements for a
certain time, the ventricles during a longer
period, sometimes even for two hours. He adds,
we thus transfer from the right auricle to the
left ventricle the property of being the last
living part in the body, in preserving for it
during a longer period the irritation produced
by the contact of blood. These experiments
of Haller certainly shew that the left side of
the heart will continue to contract longer than
the right where it is subjected to a stimulant
of which the other is deprived ; but they do not
entitle us to conclude that the persistence of
their contractility is the same when placed un-
der similar circumstances. We have every
reason for believing that the right auricle is the
part of the heart which last loses its contracti-
lity. Indeed Haller himself confesses, that if
any part of the heart remains longer contractile
than another, it is the right auricle. Nysten,f
who performed a number of experiments upon
the comparative persistence of the irritability
in the different contractile parts of the body in
the human species, after decapitation by the
guillotine, and when the heart was conse-
quently emptied of its blood, obtained the fol-
lowing results upon the order in which the dif-
ferent parts of the heart lose their contractility :
— 1st, the left ventricle, the contractility of
which is annihilated much more quickly than
that of the other organs ; 2d, the right ventri-
cle, the movements of which generally continue
more than an hour after death ; 3d, the two
auricles, the right being of all the parts of the
heart that which preserves for the longest time
its contractile power.

The stimulant used in these experiments was
galvanism. The greater persistence of the con-
tractility in the right auricle over the other parts
of the heart has been observed by other experi-
menters, after it had been cut from the body,
and consequently without any contained blood.
The particular part of the auricle which last
loses its contractility varies in different cases.
Sometimes the appendix is found contracting
when the rest of the auricle is quiescent; at
other times, and perhaps more frequently, those
parts of the auricle around the entrance of the
venae cavae retain their contractility longest.

* Sur le mouvement du sang, p. 172. Similar
experiments were performed by Walther with the
same results : Experimenta de vivis animalibus,
p. 11, as quoted by Burdach.

t Recherches de Physiologic, &c. p. 321.

608

HEART.

Harvey and some of the older anatomists ob-
served the movements of the venae cavae to
continue in some of the lower animals after the
auricles had ceased to move. The apex of the
ventricles frequently remains longer contractile
than the rest of the ventricle. Haller suggested
that this might depend on the remaining blood
gravitating to the apex, and there acting as a
stimulant.

Duration of contractility after death. — In
the cold-blooded animals the heart may be
made to contract fourteen, twenty, thirty-four
hours, or even longer after death. In warm-
blooded animals the heart remains contractile
for a much shorter period after death than in
cold-blooded animals. Haller found the heart
contractile in a warm-blooded animal in one
case four hours after death, and in another
seven hours. He sometimes observed it to
cease before the vermicular motion of the intes-
tines. Wepfer found it irritable in a dog six
hours after death. Nysten, who attended par-
ticularly to this subject, found in one of his
experiments on the human subject, that the
ventricles refused to contract upon the applica-
tion of galvanism one hour after decapitation,
while the auricles continued contractile for
seven hours five minutes after death.* In ano-
ther case the right auricle was still contractile
eight hours after death ;f and in a subsequent
case which he relates, it remained contractile in
the neighbourhood of the entrance of the supe-
rior cava sixteen hours and a half after death .J
In the Mammifera, Nysten found that the left
ventricle often refused to contract thirty minutes
after death ; that the right ventricle retained its
contractility two hours, and sometimes longer,
while the right auricle was not quiescent upon
the application of the galvanism until eight
hours after death.

He found it to vary in birds according to the
degree of muscular activity which they enjoyed
during life. In those of high flight, and which
exercise great muscular contractility during life,
and have a rapid circulation, as the sparrow-
hawk, the irritability of the heart and other
muscles becomes much more speedily exhaust-
ed than in those the movements of which are
comparatively slow and feeble, as in most domes-
tic fowls.§ Nysten supposes that the explana-
tion of the greater persistence of contractility of
the right ventricle over the left lies in the cir-
cumstance that the left acts with greater vigour
during life, thus referring it to the important
general law which he has established by his
experiments upon the comparative excitability
of the muscular tissue in the various classes of
animals, that the duration of the contractility
after death is in the inverse ratio of the muscu-
lar energy developed during life. || Before we

* Op. cit. p. 316.

t Page 318.

j In these experiments all the other parts of the
body lost their contractility before the right auricle.

§ Op. cit. p. 349.

\\ Dr. Marshall Hall (Phil. Trans. 1832) has
more lately laid it down as a general law that the
irritability of the heart and other muscles is in the
inverse ratio of the oxygen consumed in respiration.

could admit this explanation, it would be ne-
cessary to show, what we believe it will be
found impossible to do, that the left ventricle,
apart from its greater quantity of muscular fibre,
exerts greater strength or exhibits more ener-
getic contractions during life than the right
ventricle. In young animals, immediately after
birth, the contractility of the heart continues
longer after death than in the adult animal.
We would expect this to be most apparent in
those which are born with their eyes shut, as
puppies and kittens, and in those birds which
are hatched without feathers, since these ani-
mals at that period of life approach in their
physiological conditions to the cold-blooded
animals. There is a curious circumstance
stated by Mangili, and confirmed by Dr. Mar-
shall Hall, connected with the hybernation of
animals, that if those mammalia which hyber-
nate are killed while under a state of lethargy,
the heart and other muscles remain contractile
for a longer period than when they are killed
in a state of activity, thus resembling, when
under the influence of this lethargy, in this as
in many other respects, the physiological con-
dition of the cold-blooded animals. The con-
tractions of the heart may frequently be renewed
by the application of warmth after they have
apparently ceased. I have repeatedly observed
the fact which has been stated by Haller and
Nysten, that when any of the cavities of the
heart become congested with blood, their con-
tractility becomes arrested, and, in their opi-
nion, extinguished.* I have also found that
unloading the right side of the heart soon after
the congestion has taken place, which can be
done in many cases by opening the external
jugular vein, acts as a valuable adjuvant under
certain circumstances in renewing the heart's
action. These it would be out of place to dis-
cuss here ; but I may state that it appears to
me to be principally useful in certain cases of
poisoning, in asphyxia, and after the accidental
entrance of air into the veins. Since the intro-
duction of a considerable quantity of air into
the veins produces death by mechanically ar-
resting the movements of the right side of the
heart, we believe that circumstances may occur
in which the surgeon may be justified in intro-
ducing a tube into one of the large veins pass-
ing into the upper part of the chest, and suck-
Various experimenters distinctly show that as we
descend in the scale of animals the quantity of oxy-
gen consumed diminishes, and that Birds consume
more than Mammalia. Dr. Edwards has also
shown that the young of the Mammalia deteriorate
the atmospheric air less rapidly than the adult ani-
mals ; and the experiments of Mangili and Prinella
prove that hybernating animals, when in a state of
lethargy, consume exceedingly little oxygen, so
that there is evidently some relation between irri-
tability'and the quantity of oxygen consumed in re-
spiration ; but for the proof that the irritability is
exactly in the inverse ratio of the respiration, we
must wait for Dr. Marshall Hall's promised experi-
ments.

* Haller supposed that this was effected, as must
be if allowed to continue for any length of time,
by the too great distension of the muscular fibres,
in the same manner as distension of the bladder
produces paralysis of its fibres.

HEART.

C09

ing the frothy blood from the right side of the
heart. It is also necessary to remember this
circumstance in experimenting upon the .length
of time during which the heart remains con-
tractile after death, as the division or non-divi-
sion of the large veins at the root of the neck
in laying open the thorax may considerably
modify the results.*

For the probable force exerted by the heart,
the share which the heart has in carrying on the
circulation, and the probable quantity of blood
expelled at each contraction, see the article
CIRCULATION.

Frequency of the heart's action. — The fre-
quency of the heart's action is considerably
modified by aee, condition of the other functions
of the body at the time, by mental emotions, and
by the original constitution of the individual.
Its movements are influenced by very slight
muscular exertion, and the extent of this appears
to vary at different times of the day. In the
foetus its movements are rapid, being about
140 in the minute. At birth it is from 130 to
140; at one year 115 to 130; second year
100 to 115; third 90 to 100; seventh 85 to
90; fourteenth 80 to 85; middle age 70 to
75; in very old age 50 to 65. The heart's
action generallysympathises powerfully with the
other organs of the body, and this has always
been regarded as a most important and necessary
guide in the detection and cure of diseases.

It becomes strong and rapid in some cases of
inflammation, while in others it becomes rapid
and feeble. It becomes quicker after eating
and slower during sleep. It is much increased
in frequency during bodily exertion. In cases
of great general debility it becomes very quick
and feeble. It becomes more rapid and
weaker during inspiration, slower and stronger
during expiration.

It is an important fact that when the con-
tractility of the heart is much enfeebled by
extensive injuries of the central organs of the
nervous system or of the other parts of the body,
(as when a limb is extensively crushed,) its
contractions are not only much weaker, but are
also greatly increased in frequency. It is also
worthy of remark that such injuries do not pro-
duce convulsive movements in this organ. The
effect which severe injuries and certain inflam-
matory affections have in greatly debilitating or
even destroying the contractility of the heart is
a fact of great practical importance, as it not
only explains the cause of the most alarming
symptoms in such cases, but also points out the
most appropriate remedies to avoid the chief
tendency to death. To this cause, for example,
we are to attribute the rapid and feeble pulse,
in concussion of the brain, in extensive mecha-
nical injuries, the shock after operations, exten-

iburgh Medical and Surgical Journal, 1836.
performed these experiments, I was not

* Edinbui

When I performed these experiments
aware that I had been anticipated to a certain ex-
tent by Mr. Coleman. (Wilson on the Blood, &c.
p. 131 . ) It is very possible that the sinuses upon
the interior cava and hepatic veins in the seal may,
besides answering other purposes, have the effect
of preventing this mechanical distension of the
right side of the heart.
VOL. II.

sive burns, peritonitis, &c. It is very fortunate
that the contractions of the heart become more
frequent when its contractility becomes en-
feebled. If the heart under these circumstances
had required, as we would a priori expect, the
presence of a greater quantity of blood to
stimulate it to contraction, instead of a smaller
quantity, as is actually the case, what would
have been the consequence ? It is evident
that since the resistance, under ordinary cir-
cumstances, which the heart has to overcome in
contracting, is, according to a well-known hy-
drostatic law, in proportion to the extent of the
area of the inner surface of the cavities of the
heart at the commencement of their contraction,
(each square inch of surface, according to the
experiments of Hales, having a pressure upon
it nearly equal to four pounds,) the more fre-
quent contractions, where there is a smaller
quantity of blood present in the heart at the
commencement of each contraction, will not
demand the same degree of muscular force for
their performance, as if these had been less
frequent. If, when the contractility of the
heart became debilitated, the presence of a
greater quantity of blood than usual in its
interior had been necessary to stimulate it to
contraction, and if the area of the inner surface
of the cavities of the heart be in proportion to
the quantity of blood contained there, it is
apparent that the movements of the heart would
have been much more rapidly and frequently
arrested when its contractility became enfeebled ,
than they are under the actual arrangement.

The influence of mental emotions upon the
movements of the heart requires no illustration,
for this is so universally experienced that in
common language the heart is considered to be
the seat of the affections and passions, and this
has had a powerful influence upon the phrase-
ology of all languages.

In sanguine temperaments the heart gene-
rally contracts more frequently than in phlegmatic
temperaments. In women it is also generally
a little quicker than in men.

It varies very much in different classes of
animals.

Burdach* has given the following table col-
lected from numerous sources, as an approxi-
mative valuation of the frequency of the heart's
action in various animals.

Number of pulsations in a minute.\

In the Shark . . 7

Mussel 15

Carp 20

Eel 24

Snake 34

Horse 36

Caterpillar 36

Bullock 38

* Physiologic, vol. iv. p. 251.

t We cannot consider the number of pulsations
of the heart in a minute given in the above table
as by any means quite satisfactory. The number
of pulsations in the ox and horse is given on the
authority of Vetel in Froriep, Notizen, t. xxiv. p.
112. Other observers state the number of pulsa-
tions in a minute at from 38 to 52 in the horse, and
from 64 to 70 in the ox.

2 S

610

HEART.

Ass 50

Crab 50

Butterfly 60

Goat 74

Sheep 75

Hedgehog 75

Frog 77

Marmot _ 90

Locust 90

Ape 9o

Dormouse 105

Cat .. 110

Duck 110

Rabbit 120

Menoculus Caster 1 20

Pigeon . . . .^ 1 30

Guinea-pig 140

Hen „. 140

JBremus terrestris 1 40

Heron 200

Menoculus pulex 200

For the effects of the respiration upon the
contractions of the heart, and the influence of
the circulation of dark blood upon its irrita-
bility, see ASPHYXIA.

The cause of the motion of the heart. — The
motion of the heart, and the constancy and
regularity of its movements, are circumstances
so remarkable that they could not fail early to
excite a deep interest among medical philo-
sophers when they had once turned their
attention to the explanation of vital phenomena.
When we contemplate the heart commencing
its movements at an early period of fcetal
existence, and never resting from its apparently
unceasing toil until the latest moments of life,
and when we remember the uniform and regu-
lar manner in which all its actions are accom-
plished— all conspiring for the proper per-
formance of the deeply important functions
assigned to it, we are at first impressed with the
idea that it is regulated by laws different from
similar textures of the body, and altogether
peculiar to itself. It must have been under
the influence of similar impressions that the
older medical philosophers approached this
subject, and it is in this manner only that we
can account for many of the strange specula-
tions on the heart's action which they have left
recorded.

We find one sect attempting to explain it by
a peculiar innate fire. Sylvius, the head of the
chemical sect, had recourse for its explanation
to an effervescence excited by the intermixture
of the old and alkaline blood with the acid
chyle and acid pancreatic lymph.* Descartes
supposed that a constant succession of explosions
occurred in the heart from steam generated
there, which propelled the blood through the
body. Stahl got at once out of the difficulty
by affirming that the heart was more particu-
larly under the guidance of the anima or soul.
But we cannot here dwell longer on these ob-

* In the same manner Borelli says, " Constat
ex dictis immedhitam causam motivam cordis esse
ebullitionem fermativam tartarei sncci sanguine!
excitatam a commistione succi spiriluosi a iiervis
instillati." De Motu Animalium, p. 97.

solete and to us in the present time almost
incredible opinions, and the only use to which
they are now applicable is to serve as beacons
to keep us, in all our inquiries into the pheno-
mena of living bodies, within the strict path of
facts and observation, and to forcibly impress
upon us into what strange and fatal errors even
the brightest intellects may fall, when they
leave the inductive method of investigation,
and wander into the alluring but dangerous
regions of hypothesis. And the effects of these
errors are only the more to be dreaded as they
are often clothed in the most seductive in-
genuity. It ought also still more forcibly to
inculcate upon us the important truth, which,
though generally in our mouths, is not unfre-
quently forgotten in practice, — that as the
material world and all which it contains have
been placed by the Author of Nature under
arbitrary and fixed laws, it is impossible to ex-
tend our knowledge of these by theorizing in
the closet, and that this can only be effected by
the patient interrogation of Nature herself.

It was not until the time of Senac and
Haller that accurate notions began to be enter-
tained on the nature of the heart's action.

The cause of the movements of the heart is
distinctly referable to the same laws which
regulate muscular contractility in other parts of
the body, only modified to adapt it for the per-
formance of its appropriate functions. Like
all the other muscles it is endowed with irrita-
bility, which enables it to contract upon the
application of a stimulus. The ordinary and
natural stimulus of the heart is the blood,
which is constantly flowing into its cavities.
The greater irritability of the inner surface over
the outer is evidently connected with the
manner in which the stimulus is habitually
applied. When the blood is forced on more
rapidly towards the heart, as in exercise, its con-
tractions become proportionally more frequent;
and when the current moves on more slowly,
as in a state of rest, its frequency becomes pro-
portionally diminished. If the contractions of
the heart were not dependent upon the blood,
and their number regulated by the quantity
flowing into its cavities, very seiious and in-
evitably fatal disturbances in the circulation
would soon take place.

As the heart continues to contract often for a
very considerable time after the venae cavae
have been tied, and after the blood has ceased
to pass through its cavities, or after it has been
removed from the body, this has been supposed
by some to indicate that there is something in
the heart's structure or in its vital properties
which enables its movements to proceed inde-
pendent of all other circumstances. But in all
these cases a stimulus has been applied in some
form or other to the heart. If the heart has
been allowed to remain in its place, though the
circulation of the blood may have come to a
stand, part of it may yet remain in the different
cavities of the organ ; or if the pericardium has
been opened, the impression of the external
atmosphere may act as a stimulus. The expe-
riments of Walther and Haller formerly men-
tioned upon the comparative irritability of the

HEART.

611

two sides of the heart, and the different results
obtained when the one side of the heart was
emptied of blood, and when it was retained in
the other, are sufficient to shew the effect which
the presence of blood in the cavities of this
organ has upon the continuance of its action
after the circulation has ceased. If the heart
has been removed from the body and emptied
of its blood, it must naturally follow that its
different cavities will be tilled with atmospheric
air; and it has been well ascertained that this
acts as a very powerful stimulant upon the
inner surface of the heart.* Every circumstance
connected with these experiments is in exact
conformity with the opinion that the movements
of the heart are only called into action by the
application of a stimulant. Thus, when the
irritability of the heart becomes more languid,
and when the blood or the atmospheric
air in its cavities becomes insufficient to
raise it to contraction, strong and energetic
movements may still generally be excited by
having recourse to a more powerful stimulant,
such as the prick of a scalpel or the application
of galvanism. Since the heart is highly en-
dowed with irritability, various other mild fluids
besides the blood are capable of exciting it to
contraction. As every organ, however, has its
irritability adapted for the function which it is
destined to perform, so we find that the heart,
the central organ of the circulation, is most
fitly called into action by the blood, its appro-
priate and natural stimulant.

In examining the nature of the irritability of
the heart, and contrasting it with that of the
voluntary muscles, we must not compare its
contractions with those excited by volition in
the muscles of voluntary motion, for these last
are evidently modified by the nervous influence
for an obvious purpose ; but let us observe both
when placed under similar circumstances, and
irritated by the application of the same stimu-
lant applied to the muscles themselves, and we
will find that they only differ in this, — that in
the voluntary muscles each successive appli-
cation of the stimulant is generally followed by
a single contraction, while in the heart it is
followed, except when the contractility is
much impaired, by several consecutive con-
tractions alternated with relaxations. This ten-
dency to successive contractions is also observed,
though not to the same extent, in the muscular
coat of the intestines.

We must admit, however, that the contrac-
tions of the heart proceed under circumstances
where it is difficult to point out the presence
of any sufficient stimulus, and where, to account
for their continuance, we are almost obliged to
have recourse to the supposition, that there is
some innate moving power in the heart itself.
It has been stated, for example, that the move-

* Peyer, Brunner, and Haller have seen the con-
tractions of the heart renewed by blowing air into
the cava ascendens. Wepfer and Steno produced
the same effect by inflation of the thoracic duct.
Enman states that he once observed the renewal
of the heart's action in the human subject by
blowing air into the thoracic duct. Vide Senac. torn,
i. p. 326.

ments of the heart will proceed under the ex-
hausted receiver of an air-pump. I have
repeatedly placed under the bell-glass of an
air-pump the heart of a frog when removed from
the body and emptied of its blood, and I could
never satisfy myself that the frequency or
strength of its contractions was at all affected
by the withdrawal or renewal of the air ; and
though it might be urged that the air is only
rarefied, not entirely removed, in the best ex-
hausted receiver of an air-pump, and that con-
sequently in such experiments a stimulant still
existed in the presence of the rarefied air, yet
I would not consider this explanation of the
continuance of its contractions by any means
satisfactory. In these experiments there is ano-
ther source of stimulation present which ought
to be taken into account, for, as I shall after-
wards shew, the slightest movement of the
heart, such as that caused by its contraction,
upon the surface upon which it is placed when
removed from the body, is sufficient, from the
great irritability of the organ, to act as a stimu-
lant upon it. If these external stimuli appear
to be insufficient to account for the persistence
of the contractions of the heart under the cir-
cumstances we have mentioned, we may have
recourse to another explanation drawn from the
mechanical structure of the organ; for it is
possible, as has been suggested by Dr. Alison,
that from the peculiarly convoluted arrangement
of the fibres, the outer may, during the con-
traction of the organ, pinch or stimulate the
inner, and so cause this tendency to repeated
contractions from one application of a stimu-
lant. We do not, however, consider that we
have succeeded perfectly in accounting for the
continuance of the contractions of the heart
under all circumstances, but we are unwilling
to admit the existence of any peculiar innate
and unknown agency in the production of any
phenomenon, until it is satisfactorily established
that it cannot be accounted for on the known
laws which regulate similar phenomena in the
same texture in other parts of the body. And
it must also be remembered that these move-
ments of the heart have only been observed
when its contractility was still comparatively
vigorous, and where sources of stimulation
were still present. We ought, besides, to be
the more cautious in admitting the existence
of this innate moving power, since it is in
opposition to a well-known law in the animal
economy, — that though the various tissues of
an organized body are endowed with certain
vital properties, yet the application of certain
external and internal stimuli is necessary to
produce their manifestations of activity. In
fact it is from the action and reaction of these
tissues and excitants upon each other, that the
phenomena of life result.*

* The remarks which we have made above,
illustrating the great length of time which the heart
•will continue to contract after being removed from
the body, and when all communication between the
nerves ramified in ics substance and the sympathetic
ganglia and the central organs of th? nervous sys-
tem have been cut off, when taken along with the
equally well ascertained fact, that its contractions
2 S 2

012

HEART.

Upon what does this irritability of the heart
depend ? — This has been one of the most keenly
agitated questions in physiology, as a great part
of the experiments, and much of the reasoning
upon the nature of muscular irritability, have
been furnished by this organ. As, however,
the general doctrines entertained on this subject
have already been full} discussed under the
article CONTRACTILITY, we shall here confine
ourselves to a few of the leading facts connected
with it which have a special reference to the
heart. The two principal questions on this
point since the time of Haller have been, whe-
ther does it depend upon nervous influence ?
or is it a property of the muscular fibre itself
independent of the nerves ?

We have seen that the nerves distributed
upon the heart are the par vagum and sympa-
thetic. Numerous experimenters have removed
portions of the par vagum on both sides of the
neck without the slightest diminution of the
strength of the contractions of the heart. These
experiments we have frequently performed with
the same results. There can now be no doubt
that the sudden death which occasionally fol-
lows this operation is not to be attributed to the
cessation of the heart's action, as some of the
older experimenters believed, but, as Legallois
has shewn, it depends upon an arrestment of
the movements of the muscles attached to the
arytenoid cartilages. Portions of the sympa-
thetic have also been destroyed in the middle
of the neck without any effect upon the con-
traction of the heart, except what could be
sufficiently accounted for by the pain of the
incisions and the terror of the animal. A por-
tion of both of the sympathetic and pneumo-
gastric nerves may be removed in the neck
with the same results; in fact we cannot, in
the dog and most quadrupeds, cut the par
vagum in the middle of the neck without also
dividing the sympathetic. Magendie affirms
that all the sympathetic ganglia of the neck,
along with the first dorsal, may be removed
without any sensible derangement of the parts
to which their nerves are distributed. Brachet*
supposes that the reason why the excision of the
sympathetic ganglia in the neck does not always
arrest the heart's action, is because there is
another source of nervous influence for the
cardiac nerves placed below this in the cardiac
plexus or ganglion. He accordingly put this
opinion to the test of experiment, and he as-
sures us that the total destruction of the cardiac
plexus was followed by the sudden and perma-
nent arrestment of the heart's action. Now

may be readily increased or renewed under those
circumstances, by mild excitants applied to its inner
surface, are completely opposed to the supposition
that the heart is called into contraction in a manner
similar to those sympathetic movements more lately
described under the term excito-motary. Though
this mode of explanation may be considered quite
legitimate when applied to those sympathetic move-
ments which do not require the intervention of the
brain for their performance, such as deglutition,
respiration, &c., it is certainly pushing the doctrine
far beyond its proper limits to apply it to the
explanation of the movements of the heart.
* Du systeme nerveux ganglionairc, p. 120.

when we consider the nature of such an ex-
periment as this, with the chest of the animal
laid open, the respiration arrested, and the
heart exposed during the time the experimenter
is searching and tearing for the plexus placed
deep behind the aorta and pulmonary artery,
and which would require a considerable time
to display even in the dead body when unem-
barrassed by the movements of the heart, we
must be more astonished that the action of the
heart had not completely ceased before the ex-
periment was finished, than that it should have
continued so long. Besides, even allowing that
this experiment could be relied upon, we have
sufficient evidence, from the facts stated above,
to entitle us to conclude that the heart is not
dependent for its movement upon any influence
constantly transmitted along its nerves from the
central organs of the nervous system, — the
brain and spinal marrow. Brachet is himself
obliged to admit, from other experiments which
he performed, that the division of the sympa-
thetic at the lower part of the neck is not suffi-
cient to arrest the heart's action, so that this
experiment is intended to shew that its irrita-
bility depends upon the ganglia of the sympa-
thetic itself. The independence of the irrita-
bility of the heart upon the brain and spinal
marrow can be very satisfactorily proved in
another manner. The occurrence of acephalous
monsters,* and the experiments of Wilson
Philip,f Clift,| and Brachet§ demonstrate that
the brain or spinal marrow may be naturally
wanting ; that one or both of them may be
removed entirely, or destroyed in small portions
at a time, without arresting the heart's action.
We may here observe that the experiments of
Legallois,|| Wilson Philip, Wedemeyer,^[ Bra-
chet, and many others, in which the action of
the heart was arrested by crushing large portions
of the brain or spinal marrow, though they do
not prove the dependence of the irritability of
the heart upon the brain and spinal cord, at
least shew, what the effects of mental emotions
upon the movements of the heart had already
pointed out, that it can be influenced to a great
and most important extent through these organs.
The advocates for the dependence of the irrita-
bility of the heart upon the nerves appear to
have pretty generally abandoned the opinion
that this is derived from the central organs of
the nervous system, and now maintain the
doctrine, which was more prominently deve-
loped by Bichat, that this is derived from the
sympathetic, the ganglia of which, according
to him, are independent sources of nervous
influence. From the manner in which the
sympathetic is distributed upon the heart, it is

* The heart is generally though not always ab-
sent in acephalous monsters.

f Experimental Inquiry into the vital functions.

J Phil. Trans. 1815.

$ Systeme nerveux ganglionaire.

f| Legallois performed these experiments on the
spinal cord alone, and supposed he had proved
that the movements of the heart were dependent
upon that portion of the nervous system.

TJ Physiol. Untersuchungen Uber das Nerven-
system, £c. p. 235.

HEART.

613

perfectly impossible to insulate that organ from
the nerve and experiment upon it; but we
think we are justified in concluding from ob-
servations and experiments derived from other
sources, that in all probability the contractility
of the heart depends upon a property possessed
by the muscular fibre itself without any neces-
sary intervention of its nerves. The possibility
of exciting or increasing the action of the heart
by stimuli applied to its nerves has been mixed
up with this question. Though it must be
admitted that mechanical and chemical stimu-
lants applied to a considerable surface of the
central organs of the nervous system quicken
the heart's action, yet experimenters have gene-
rally acknowledged that these stimulants applied
to the nerves of the heart produce no effect
upon its movements. Burdach,* however,
maintains that he has quickened the heart of a
rabbit deprived of sensation by applying caustic
potass to the trunk of the sympathetic, or its in-
ferior cervical ganglion. That the heart can be
excited to contraction by the application of
galvanism has had many supporters, and many
celebrated names are arranged both on the
affirmative and negative sides of the question.
That the movements of the heart may be in-
creased or renewed by the application of gal-
vanism as the experiment is usually performed,
there can be no reasonable doubt ; for if one
wire is placed upon the nerve and the other
upon the heart, the moist nerve will act as a
conductor to the electricity, and the effect pro-
duced will be the same as if the stimulant had
been applied to the substance of the heart itself.
Nysten admits that movements of the heart
were excited by the galvanism when one of the
wires was applied to one of the large arteries
from which all the visible filaments of the
nerves had been dissected off. Dr. C. Holland,!
in a number of experiments, satisfied himself
that the tissues of the body conduct galvanism
with so much facility, thai the heart's action
could readily be excited, when one wire was
placed upon the heart and the other in the nose,
mouth, and even among the moist food in the
stomach. I have performed similar experiments
with the same results. Ilumboldt and Brachet
assert that they have quickened the movements
of the heart by applying both wires to one of
the cardiac nerves. If these and the experi-
ments of Burdach could be relied upon, they
would be sufficient to prove that the heart could
be occasionally stimulated through the cardiac
nerves, but the negative experiments on the
other side are so numerous, and the sources of
fallacy in judging in this manner of the relative
quickness of the heart's action between one
time and another so obvious, that we must be
allowed to distrust them unless they should be
confirmed by other accurate observers.

Constancy of the heart's action. — The con-
stancy of the heart's action is more apparent
than real. After each contraction a state of
relaxation follows. The relative duration of

* Traite de Physiologic, torn. vii. p. 74, traduit
par Jourdan.

t Experimental Inquiry, &c. p. 275.

the contraction of the auricles and ventricles,
according to Laennec, appears to be as fol-
lows : — a third at most, or a fourth or a little
less by the systole of the auricles ; a fourth or
a little less by the state of quiescence ; and the
half or nearly so by the systole of the ventricles.
From this he calculates that the ventricles,
when the heart is acting with its usual frequency,
rest twelve hours out of the twenty-four, and
that in those individuals in whom the pulse is
naturally below 50, it must be in a state of
relaxation sixteen hours out of the twenty-four.*
Now this is a degree of contraction of which
many muscles of the body are probably suscep-
tible, such as the muscles which support the
trunk when we sit or walk, and which some,
as the diaphragm and intercostals, generally
perform.

Regularity of the heart's movements. — The
regularity of the heart's movements, so essential
to the welfare of the animal, has appeared,
even to many modern physiologists, to be inti-
mately connected with some peculiarity in its
structure. We are inclined, however, to agree
with Haller, that this is perfectly explicable on
the known laws of muscular contractility
in other parts of the body. The regularity of
the heart's action was another fertile subject of
hypothesis to the older physiologists ; and even
in the present day we find the term " organic
instinct" employed to designate it.

The contractions of the heart take place in
the order in which the blood flows into its
different cavities; and if the blood be the habi-
tual stimulant upon which its movements
depend, this is exactly what we would expect.f
The blood forced in greater quantity into the
auricles by the contraction of the termination
of the cavae and pulmonary veins, stimulates
the auricles to contract and propel an additional
quantity into the ventricles ; and this, acting as
a stimulant upon the ventricles, excites them to
contract and drive the blood into the arteries,
when the same series of phenomena is renewed
and repeated in the same succession.

The continuance of the heart's action after
the circulation has ceased, we have already
attempted to explain ; and if these contractions
depend upon the presence of a stimulus, they
must evidently be in the same order as in the
natural state of the organ, as these have not
been interrupted. The continuance of the re-
gular order of the contractions of the heart
after its removal from the body can in general,
we think, be satisfactorily accounted for by
the substitution of a new stimulant for that
of the blood ; the cavities are then occu-
pied with air instead of blood, and each

* We have "not here given Laennec's calculations
of the relative duration of the contraction and
relaxation of the auricles, as they must be founded
on false data — on the supposition that the second
sound of the heart marked the duration of the con-
traction of the auricles.

t This was also the doctrine maintained by Se-
nac, op. cit. torn. i. p. 325. Senac, however, was
opposed to the doctrine of Haller, that the contrac-
tility of the heart was a property inherent in the
muscular fibre, and independent of the nerves.
Tom. i. p. 451.

614

HEART.

contraction of the auricle must force an ad-
ditional quantity into the ventricle, and this,
though small in quantity, may be quite suffi-
cient to excite the ventricles to contraction,
when the irritability is not too much impaired.*
It is only in this manner, taken along with the
greater irritability of the internal surface over
the external, that we can explain the observa-
tion made by Dr. Knox in the course of his
experiments upon the irritability of the heart
in fishes, where, when the irritability was nearly
exhausted, contractions excited in the auricle
were sometimes followed by contractions of the
ventricle, when irritation of the outer surface of
the ventricle itself produced no effect.f Cer-
tainly, under ordinary circumstances, this regu-
larity of the heart, so necessary for the proper
performance of its functions, is a marked fea-
ture in its action ; but that it is not either ne-
cessarily connected with its structure or vital
properties, but depends solely on the manner
in which its stimulant, the blood, is applied, is
proved by various facts. 1st. The movements
of the auricles and ventricles generally cease at
different times after death ; and though the
auricles much more frequently continue to con-
tract after the ventricles, yet several accurate
experimenters have observed the left auricle
become quiescent before its corresponding
ventricle.^ 2dly. When the movements of
the ventricle have ceased, while the auricles
continue to contract, the ventricle may generally
be excited to vigorous contractions by the ap-
plication of a powerful stimulus. 3dly. When
the irritability of the heart becomes somewhat
languid, two, three, or sometimes six or seven
contractions of the auricle may take place be-
fore the ventricles are roused to contraction ;
the evident deduction from which is, that the

* When the heart has ceased to contract, it may
frequently be called into pretty vigorous action by
opening one of the large veins, and blowing some
air into its cavities.

t I have repeatedly attempted to ascertain if the
circumstances here described as sometimes occurring
in the cold-blooded animals could be observed in
the warm-blooded animals, but without success.
In one experiment upon the heart of a rabbit, after
all the movements of the ventricles had ceased,
but where tliey could still be readily excited by the
application of a stimulant, we were convinced that
contraction of the auricle, when excited by stimu-
lation applied to itself alone, was sometimes fol-
lowed by contaction of the ventricle even after
the ventricle had been slit open. But in subsequent
experiments upon dogs, we ascertained a source of
fallacy which we had overlooked in the other expe-
riment, for we found that a slight movement of
the heart on the surface upon which it rests, such
as that caused by a very gentle pull at the large
arteries, and not exceeding the effects produced by
the contraction of the auricle, was, in some of
these cases, sufficient to excite contractions of the
ventricles.

$ In one experiment upon a cat, I distinctly ob-
served the right ventricle occasionally pulsate
twice for each pulsation of the auricle. In another
experiment, I distinctly observed the contractions
of the ventricles precede those of the auricles,
when the contractility of the heart had become en-
feebled. In this case, the pause in the heart's
action occurred after the contraction of the auri>
cles.

contractions of the ventricles do not neces-
sarily follow those of the auricles, unless
the contractions of the auricles occasion the
application of a stimulant to the inner sur-
face of the ventricles sufficient to excite them
to contraction. 4thly. The movements of the
ventricles and auricles will go on in the same
manner, though detached from each other
by the knife. 5thly. If we were allowed to
argue from final causes in negative cases, we
could easily shew that a peculiar endow-
ment, such as we are contending against,
would not be of the slightest advantage in se-
curing the regularity and constancy of the
heart's movements. It appears, then, quite un-
philosophical to call in the agency of some un-
known and indefinite principle for the produc-
tion of these periodic movements, as they have
been called, of the different chambers of the
heart, when they can be satisfactorily referred
to the laws which regulate muscular contracti-
lity in other parts of the body. We have here
a beautiful example of the manner in which
nature produces adaptation of means to an end,
not by the creation of new properties, which
we, in our ignorance, sometimes erroneously
attribute to her, but by the employment of
those already in use in the performance of other
functions, only modified to accommodate them
to the circumstances under which they are
placed.

Sounds of the heart. — On applying the ear
over the region of the heart, two distinct
sounds are heard accompanying its contraction.
Though the existence of such sounds seems to
have been known to Harvey,* who compares
them to the noise made by the passage of fluids
along the oesophagus of a horse when drinking,
yet, as is well known, it is to Laennec that we
owe the first accurate description of the charac-
ter of these sounds, the order of their succes-
sion, and the manner in which they may here-
after be made available for the important pur-
poses of the diagnosis of the diseases of the
heart.

The first of these sounds is dull and pro-
longed ; the second, which follows closely upon
the first, is sharp and quick, and is likened by
Laennec to the flapping of a valve, or the lap-
ping of a dog. After the second sound a pause
ensues, at the end of which the sounds are
again heard. These three — the first sound, the
second sound, and the pause — occur in the
same uniform order, and when included along
with the movements of the heart, to which they
owe their origin, have received the term rhythm
of the heart. As the dull prolonged sound is
synchronous with the impulse of the heart, and
consequently with the contraction of its ventri-
cles, Laennec attributed this sound to the con-
traction of the ventricles. The second sound,
which is synchronous with the diastole of the
ventricles, he supposed must depend upon the
systole of the auricles ; and to this he was
naturally led by the supposition that their con-
traction must also produce some sound. From
the weight of Laennec's authority, this opinion

* Op, cit. cap. v.

HEART.

615

seems to have been almost implicitly adopted un-
til the appearance of a paper by the late Professor
Turner, in 1829. Professor Turner there re-
called to the attention of medical men the
observations of Harvey, Lancisi, Senac, and
Haller, upon the order of succession in which
the cavities of the heart contract, which appear
to have been forgotten amidst admiration at
the brilliancy of Laennec's progress. He also
pointed out from their experiments that if the
second sound was dependent upon the con-
traction of the auricles, it ought to precede
instead of following the first sound, and that
the pause ought to occur after the first sound,
and not after the second. He also adduced, in
farther proof of Laennec's error, observations
drawn from the effects of disease, when, from
some impediment to the passage of the blood
from the right auricle into the ventricle, a dis-
tinct regurgitation takes place into the large
veins at the root of the neck, and showed that
in these cases the regurgitation marking the
contraction of the auricles occurs without any
accompanying sound ; that immediately after-
wards the impulse is felt attended by the first
sound, and that the second sound takes
place during the diastole of the ventricles
and the passive condition of the auricles.
He suggested that the second sound might be
accounted for by the falling back of the heart
into the pericardium during its diastole, to
which " the elasticity of the ventricles at the
commencement of the diastole, attracting the
fluid by suction from their corresponding auri-
cles, may perhaps contribute." Soon after the
appearance of Mr. Turner's paper, Laennec's
explanation of the cause of the second sound
appears to have been pretty generally aban-
doned ; and numerous attempts, both in this
country and in France, have since that time
been made to solve this difficulty. Some of
these explanations appear to be mere guesses,
occasionally at total variance with the anato-
mical structure of the organ, and at times pre-
senting even as wide a departure from its nor-
mal action as that given by Laennec himself.
Others, again, have entered upon an experi-
mental investigation of the subject with en-
lightened views of its anatomy and physiology,
have furnished us with much additional infor-
mation, and lead us to indulge in the pleasing
prospect that in a short time the matter will be
completely set at rest.

The result of the experiments of Hope and
Williams, attested as they have been by various
gentlemen well qualified to judge of their
accuracy, — also those of Mr.Carlisle, Magendie,
Bouillaud, and the Dublin Committee, have
satisfactorily determined that the account of the
order of the contractions of the heart, and
their isochronism to the sounds as stated by
Mr. Turner, are perfectly correct. As, how-
ever, so many different circumstances attend
each movement of the heart, any one of which
may be capable of producing these sounds, it
became a much more difficult matter, and one
requiring great perseverance and accuracy of
investigation, to determine upon what particular
one or more of these, each sound depends.

For accompanying, and synchronous with the
first sound, we have the contraction of the ven-
tricles, the collision of the different currents of
blood contained there thus set in motion, the
approximating of the auriculo-ventricular valves,
the impulse of the heart against the chest, and
the propulsion of the blood along the large
arteries; while attending the second sound, we
have the diastole of the ventricles, and the rush
of a certain quantity of blood from the auricles
into the ventricles, the sudden separation of
the auriculo-ventricular valves towards the
walls of the ventricles, and the regurgitation of
part of the blood in the arteries upon the semi-
lunar valves, throwing them inwards towards
the axes of the vessels ; so we will find that
each of these in its turn has been thought ca-
pable of producing the sound which it accompa-
nies, and stillhas,oruntil lately had, its advocates
and supporters. As the subject is one surrounded
with numerous and unusual difficulties, and is of
comparatively recent investigation, it has fol-
lowed, as was to be anticipated, that as new
facts and observations are collected, many of
the opinions first promulgated on this question
have required to be modified or changed ; and
the scientific candour displayed by several of
these authors in renouncing former published
opinions is deserving of the highest praise.

Several of the explanations of the cause of
the sounds of the heart proceed, however, upon
the supposition that the relation of these sounds
to the movements of the organ is different
from what has been here represented. We
shall merely state these without alluding to the
arguments adduced in support of them, as we
believe that they are founded upon inaccurate
observation. Sir D. Barry believed that the
first sound was synchronous with the diastole
of the auricles, and the second sound with the
diastole of the ventricles. Mr. Pigeaux, Dr.
Corrigan also until lately, Dr. Stokes, Mr.
Hart, and Mr. Beau, have maintained that the
first sound is synchronous with the diastole,
and not with the systole of the ventricles. Ac-
cording to Mr. Pigeaux, when the auricles
contract they project the blood against the walls
of the ventricle, and a dull sound (first sound)
is produced ; on the other hand, whilst the
ventricles contract, they project the blood
against the thin walls of the great vessels which
spring from them, and a clear sound (second
sound) is the result. Dr. Corrigan supposed
that the first sound was produced by the rush
of blood from the auricles into the dilating
ventricles, and that the second sound owed its
origin to the striking together of the internal
surfaces of the ventricles during their contrac-
tion, after they had expelled all their blood.
Mr. Beau believes with M. Magendie that the
first sound arises from the impulse of the
heart against the inner surface of the chest, but
differs from him in maintaining that this occurs
during its diastole, and not during its systole.
The second sound he believes to depend upon
the dilatation of the auricles. M. Piorry has
revived the obsolete and perfectly untenable
opinion of Nicholl, that the two ventricles
contract at different times, and attributes

616

the dull sound to the contraction of the left
ventricle, and the clear sound to the contraction
of the right ventricle. Dr. David Williams,
while he believes that the first sound depends
upon the rush of blood into the large arteries
during the systole of the ventricles, attributes
the second sound to the musculi papillares,
which he considers as forming part of the val-
vular apparatus, causing the valves to strike
against the walls of the ventricles. These mus-
culi papillares do not, in his opinion, contract
during the systole of the ventricles, but imme-
diately afterwards, for the purpose of throwing
open the auriculo-ventricular valves. In a
former part of this article several circum-
stances are stated adverse to this opinion.

We shall now proceed to the explanation of
the cause of these sounds given by those who
maintain the views of the rhythm of the heart
which we have here adopted, as resting upon
the concurrent testimony of numerous accurate
observers. These may be divided into those
who attribute both sounds to causes intrinsic to
the organ, or, in other words, to circumstances
occurring within the organ itself, and into those
who place them external to the organ, and
depending upon extraneous objects. The only
supporters of the latter opinion are Magendie
and his followers. Magendie maintains that
'* in contracting, and for causes long since known,
the ventricles throw the apex of the heart
against the left lateral part of the thorax, and
thus produce the first sound, z. e.f the dull
sound. In dilating, in a great measure under
the influence of the rapid influx of the blood,
the heart gives a shock to the anterior paries
on the right of the thorax, and thus produces
the second sound, the clear sound." In proof
of this, he states that on removing the sternum
of a swan (an animal selected expressly for
the experiment, as it interfered less with the
natural action of the heart than in the Mam-
malia), he found that the movements of the
heart produced no sound, while, on replacing
the sternum, and allowing the heart to impinge
upon its posterior surface as in the natural
state, both sounds were again distinctly heard.
He adduces several arguments drawn from the
action of the heart both in its healthy and dis-
eased state in favour of his opinion ; and he
ingeniously attempts to get rid of the objection
which must instantly suggest itself, that in
many cases, such as frequently occur in hyper-
trophy of the organ, the loudness of the sounds
is diminished, while the force of the impulse
is increased, by arguing that in these cases this
increased impulse depends rather upon a
heaving of the chest produced by the heart,
which from its increased size is brought close
to its inner surface, than upon a distinct im-
pingement upon it, such as takes place in the
healthy state. Dr. Hope, M. Bouillaud, Dr. C.
J. B. Williams, and the Dublin and London
Heart Commitees have, however, distinctly
heard both sounds of the heart, after that por-
tion of the chest against which it impinges had
been removed. It may, nevertheless, be objected
to these experiments, that as the stethoscope was
used in many of them, the impulse of the heart

HEART.

against the extremity may have produced an
effect similar to its impulse against the parietes
of the thorax. M. Bouillaud, having appa-
rently this objection in view, states that the
rubbing of the heart during its movements
against the extremity of the stethoscope, is
easily distinguished from the sounds of the
heart; and that he has distinctly heard both
sounds, though feebler than through a stetho-
scope, as was to be expected when nothing but
a cloth was interposed between his naked ear
and the surface of the heart. Dr. C. J. B.
Williams, in his experiments, heard both sounds
when the stethoscope was placed over the origin
of the large arteries, and where no external
impulse could take place ; and this observation
was repeated by the Dublin Committee. The
Dublin Committee heard both sounds through
the stethoscope, though feebler after the peri-
cardium had been injected with tepid water ;
and in another experiment they were also
heard when the ear was simply approximated
to the organ. From all these experiments, I
think there can be little doubt that the move-
ments of the heart, independent of all extra-
neous circumstances, are attended by a double
sound. As the impulse of the heart against
the chest must produce some sound, as any
one may convince himself by making the ex-
periment in the dead body, and as this occurs
during the systole of the heart, or, in other
words, during the first sound, it may increase
the intensity of that sound. Dr. R. Spittal,*
after relating several experiments in which a
sound similar to that of the first sound of the
heart was heard by tapping gently with the
apex of the heart or the point of the finger
against the chest, both when empty and when
filled with water, and after pointing out several
sources of fallacy which he supposes were not
sufficiently guarded against in the experiments
which we have adduced above as subversive of
this view, and which deserve the attention of
future experimenters, comes to the conclusion
that " it is highly probable that the percussion
of the heart against the thoracic parietes during
the contraction of the ventricles assists mate-
rally in the production of the first sound."
He is also inclined to believe " that the act of
the separation of the heart from the thorax after
its approach, which was found in his experiment
to produce a sharp, short sound, somewhat
resembling the ordinary sound, may in certain
circumstances be an assistant cause to the
second sound. "f Magendie's explanation of
the second sound is completely untenable.

Among those who maintain that these sounds
depend upon causes intrinsic to the heart, the
Jirst sound is referred by Rouanet, Billing,
Bryan, and Bouillaud to the rapid approxima-
tion of the auriculo-ventricular valves during
the systole of the ventricles, to which Bouillaud

* Edin. Med. and Surg. Journal, July 1836.

f Though Dr. Spittal is inclined to believe that
the impulse of the heart against the chest has con-
siderable share in the production of the first sound,
he does not concur with Majc-ndie in the explana-
tion of the second sound.

HEART.

617

adds the sudden separation of the semilunar
valves when the blood is forced into the large
arteries; by Mr. Carlisle to the rushing of the
blood along the inner surface of the large
arteries during the systole of the ventricles.*
Dr. Hope, in the appendix to the second
edition of his work, describes it as consisting,
1st, possibly of a degree of valvular sound;
2d, of a loud smart sound produced by the
abstract act of a sudden jerking extension of
the muscular walls, in the same manner that
such a sound is produced by similar extension
of the leather of a pair of bellows; to avoid
circumlocution, he calls it the sound of exten-
sion ; 3d, a prolongation and possibly an aug-
mentation of this sound by the sonorous vibra-
tions peculiar to muscular fibre." Dr. C. J. B.
Williams has very justly objected to the correct-
ness of the second cause here adduced as
aiding in the production of the first sound, as
the phrase " sound of extension" is obviously
contradictory when applied to a contracting
muscle.f Dr. C. J. B. Williams maintains
" that the first sound is produced by the mus-
cular contraction itself," the clearness of which
is increased by the quantity of blood in the
heart " affording an object around which the
fibres effectually tighten, whilst the auricular
valve, by preventing the reflux of the blood,
increases its resistance, and thus adds to the
tension necessary for its expulsion." He was
first led to the adoption of this opinion by the
observations of Enman and Wollaston upon
the existence of a sound accompanying every
rapid muscular contraction. This opinion he
afterwards put to the test of experiment, the
results of which we give in his own words.
" Experiment 1st, observation 8th; I pushed
my finger through the mitral orifice into the
left ventricle and pressed on the right so as to
prevent the influx of blood into either ventricle ;
the ventricles continued to contract strongly
(especially when irritated by the nail of the
finger on the left), and the first sound was still
distinct, but not so clear as when the ventricles
contracted on their blood. Observation 9th.
The same phenomena were observed when both
the arteries were severed from the heart." He
also found in other observations that the first
sound was louder over the surface of the ven-
tricles than over the origin of the large arteries,
which is in direct opposition to the opinion of
those who believe that this is produced by the
rush of blood along the great arteries. That
the first sound is not dependent upon the closing
of the auriculo-ventricular valves, he also
ascertained from observations, in which the
closure of these valves was partially or com-
pletely prevented, and yet the first sound was
still heard. Besides, this sound continues
during the whole of the ventricular systole,
while the shutting of the valves must take place
and be completed at the commencement of the
systole." That the collision of the particles of

* As Mr. Carlisle is a member of the Dublin
Heart Committee, we must now consider him as
concurring with the report of that Coiuuiittce.

t Medical Gazette, Sept. 1835.

fluid in the ventricles coes not produce this
sound he was convinced from observations, in
which it continued although there was no blood
in the ventricles.

Though we must admit that these experi-
ments of Dr Williams prove that part at least
of the first sound is caused by the muscular
contraction of the ventricles, yet we must con-
sider it still problematical, until we obtain
further observations, whether it produces the
whole of that sound, for it is very possible that
some of the other circumstances attending the
systole of the heart may increase its intensity.
M. Marc d'Espine has maintained that both
sounds depend on muscular movements; the
first sound upon the systole, and the second
upon the diastole of the" ventricles. The Dub-
lin Committee have in the meantime concluded
that the first sound is produced either by the
rapid passage of the blood over the irregular
internal surface of the ventricles on its way
towards the mouths of the arteries, or by the
bruit musculaire of the ventricles, or probably
by both these causes. We must wait for further
experiments before this question can be fairly
settled.*

Second sound. — Later experimenters appear
to be more nearly agreed about the cause of
the second sound than that of the first sound.
M. Rouanet appears to have been the first who
publicly maintained the opinion that the second
sound was dependent upon the shock ot blood
against the semilunar valves at the origin of
the aorta and pulmonary artery. M. Rouanet
himself acknowledges that he owed the sug-
gestion to Dr. Carswell, at that time studying
in Paris, who came to that conclusion by a
beautiful process of reasoning upon the pheno-
mena which presented themselves in a case of
aneurism of the aorta. The same opinion has
been supported by Billing, Bryan, Carlisle, and
Bouillaud.f It is, however, to Dr. C. J. B.

* The London Committee, in their report given
in at the meeting of the British Scientific Associa-
tion for 1836, have adduced some additional expe-
riments in favour of the opinion that the first
sound of the heart depends upon muscular con-
traction. It appeared to them that the sound pro-
duced by the contraction of the abdominal muscles
as heard through a flexible tube resembles the
systolic sound. They, however, admit that though
" the impulse is not the principal cause of the first
sound, it is an auxiliary and occasional cause,
nearly null in quietude and in the supine posture,
but increasing very considerably the sound of the
systole in opposite circumstances. " From the great
care with which these experiments appear to have
been performed, we believe that we are now fully
justified in adopting this explanation of the cause
of the first sound. The Dublin Committee, in their
report given in at the same time, also detail some
experiments which they believe to be confirmatory
of their former conclusions. See Sixth Report of
British Scientific Association.

t In justice to Dr. Elliott, of Carlisle, I must
state that I find, on consulting his Thesis De
Corde Humano, published in Edinburgh in 1831,
that he states (p. 53) that he believes that the
second sound of the heart is dependent upon the
rush of blood from the auricles into the ventricles
during their diastole, and also upon the sudden
napping inward of the sigmoid valves at the origin
of the large arteries by the refluent blood.

618

HEART.

Williams that we owe the first direct experi-
ments in support of it. In one experiment he
ascertained that the second sound was louder
over the origin of the large arteries than over
the surface of the ventricles, while it was the
reverse with the first sound; that pressure upon
the origin of the aorta and pulmonary artery
suspended the second sound ; and that the
second sound disappeared after the auricles
had been laid open, although the first conti-
nued. In a second experiment* we find the fol-
lowing observations stated : — " Observation 6.
A common dissecting hook was passed into
the pulmonary artery, and was made to draw
back and thus prevent the closure of the semi-
lunar valves ; the second sound was evidently
weakened and a hissing murmur accompanied
it. A shoemaker's curved awl was then passed
into the aorta so as to act in the same way on
the aortic valves. The second sound now
entirely censed and was replaced by a hissing.
Observation 7. The hook and the awl were
withdrawn ; the second sound returned and the
hissing ceased. Observation 8. The experi-
ment 6th was repeated with the same result,
and whilst Dr. Hope listened I withdrew the
awl from the aorta. He immediately said,
' Now I hear the second sound.' I then
removed the hook from the pulmonary artery ;
Dr. Hope said, ' Now the second sound is
stronger and the murmur has ceased.' " The
Dublin Committee have repeated and con-
firmed these experiments of Dr. Williams. In
their experiments one of the valves in each
artery was transfixed and confined to the side
of the vessel by a needle, and the second sound
disappeared ; on withdrawing the needles they
re-appeared.

As the second sound thus appears to be pro-
duced by the shock of the blood upon the semi-
lunar valves, its intensity must, in a great
measure, depend upon the diastole of the ven-
tricle drawing part of the blood back upon
them, but perhaps more particularly upon the
elasticity of the large arteries returning suddenly
upon their contents during the diastole of the
ventricles, when the distending force of the
ventricles has been withdrawn. \Ve would
therefore expect that the second sound should
be louder in those whose aorta retains its elas-
ticity, than in those (a circumstance sufficiently
common in old age) in whom, from a morbid
alteration of the structure of its coats, the
elasticity is either lost or greatly diminished.
This is an observation which, as far as I know,
has not yet been verified ; but my friend Dr.
W. Henderson informs me that he is positive
from numerous observations that the second
sound is louder in young than in older persons ;
but whether this is in the exact ratio of the
change upon the elasticity of the coats of the
large vessels he is not at present prepared to
say.

* These experiments were performed upon asses,
in which the sensation was first suspended by a
dose of wourara poison and then maintaining arti-
ficial respiration. In this manner the heart con-
tinued to act upwards of an hour after the com-
mencement of the artificial respiration.

BIBLIOGRAPHY.— As a complete bibliography of
the Anatomy and Physiology of the Heart would
include all the systematic works on Anatomy and
Physiology, we shall here confine ourselves to the
enumeration of those works and memoirs which
treat exclusively or in a prominent manner of the
normal anatomy or functions of that organ.

Harvey, De motu cordis, Rot. 1661. Lower
(Richard), Tractus de corde, &c. Lond. 1669.
Pechlinus (John Nicol), Dissertat. de fabrica et
usu cordis, Kiel. 1676. Bartholin (Casp.), Dis-
sert, de cordis structura et usu, Hafniae, 1678.
Charleton ( Walter), The organic structure of the
heart, Lond. 1683. Morton (C.), Dissert, de
corde, Lugd. Batav. 1683. Bellini (Laurent.),
Opuscula aliquot de urinis, de motu cordis, &c.
Lugd. Bat. 1696. 4to. Chirac (Peter), De motu
cordis adversaria analytica,, Montp. 1698. Views-
sens, Nouvelles Decouvertes sur le co?.ur, Montp.
1706. Traite nouveau de la structure du coeur, &c.
Toulouse, 1715. Thebesius, De circulo sanguinis
in corde, Leipsick, 1708. Ibid. De circulo san-
guinis per cor, Leipsick, 1759. Borelli (J. A.),
De motu animalium, Lugd. Bat. 1710. Winslow,
Sur les fibres du cceur et sur ses valves, Mem. de
1'Acad. Roy. de Paris, 1711. Morgagni (Jo.Bapt.),
Adversaria Auatomica, Lugd. Bat. 1723. Santo-
rinus, Observ. Anatomicae, Venise, 1724, cap. viii.
Ruysch, Epist. Anat. problemata decima de auri-
cularum cordis earumque fibrarum metriciam struc-
tura, Amsterdam, 1725. Lancisi (Jo. Mar.), De
motu cordis, &c. Rom. 1728. fol. Op. Om. torn. iv.
1745. 4to. Walther, De structura cordis auricu-
larum, Leipsick, 1738, reprinted in Haller's Dis-
put. Anat. torn. ii. 1747. Stuart (Alex.) De motu
et structura musculari, Lond. 1738. Examen de
la question si le cceur se raccourcit ou s'alonge
lorsqu'il se contracte, Mem. de 1'Acad. de Paris,
vol. i. p. 114. 1743. Senac, Traite de la struc-
ture du creur, de son action, &c. Paris, 1749.
torn. i. and Appendix to torn. ii. Lieutaud, Observ.
Anatom. sur le cozur, dans Memoires de 1'Acad.
de Paris, 1752-54. Haller (Albertus), Memoires
sur la nature sensible et irritable des parties du
corps animal, Laus. 1756. torn. i. Ibid. Elementa
Physiologiae, torn, i 1757. This last work, and
the Traite de la Structure du Creur, &c. of Senac,
contain a most accurate and detailed account of all
that was known upon the Anatomy and Physiology
of the Heart before and at the time they were
written. Wolff (C.F.), Dissertationes de ordine
fibrarum muscularum cordis, in A eta Acad. Petro-
polit. 1780-1792. Abernethy (John), Observations
on the Foramina Thebesii of the Heart, Phil.
Trans. 1798. Legallois, Dictionnaire des Sc. Med.
torn. v. 1813. Gerdy(P.N.), Journal Compl. du
Diction, des Sc. Med. torn. x. 1821. Recherches,
Discussions, et Propositions d'Anatomie, Physio-
logie, &c. 1823. The plates given by Gerdy in the
latter work have been copied by M. Jules-Cloquet
in his Planches d'Anat. de 1'Homme, &c. torn. iv.
Vaust (J. F.), Recherches sur la structure et les
mouvemens du coeur, Liege, 1821.

Memoirs exclusively on the relative size of the several
cavities of the heart. —Helvetius, Sur 1'inegalite de
capacitc qui se trouve entre les organs destines a
la circulation du sang dans le corps de 1'homme,
&c. Mem. de 1'Acad. de Paris, 1718. Weiss, De
dextro cordis ventriculo post mortem ampliore,
Altdorf, 1745. Avrivillius, De cavit. cordis inaequali
amplitudine, &c. Haller, Disp. Anat. Sel. vol.
viii. pars ii. p. 257. 1751. Sabatier, Mem. de
1'Acad. de Paris, 1774.

Treatises exclusively on the nerves of the heart. —
Neubauer (J. E.), Descriptio nervorum cardiaca-
rum, Frankfort et Leipsick, 1772. Andersch, De-
script, nerv. cord, in torn. ii. Ludwig Script.
Neurol. 1792. Behrends (Jo. B. 0.), Dissertatio
qua demonstratur cor nervis carere, Mayence,
1792 ; reprinted in torn. iii. Ludwig Script. Neu-
rol. torn. iii. 1793. Zerenner, An cor nervis careat
iisque carere possit ? Erford, 1794 ; reprinted in

FIBRES OF THE HEART.

619

torn. iv. Ludwig. Script. Neurol. 1795. Scarpa,
Tabulae Neurologicae, &c. Ticin. 17:- 4.

Memoirs on the peculiarities of the foetal heart. —
Memoirs upon the Foramen O'vale by Duvcrney,
Mery, Bussiere, and Littre in Mem. de 1'Acad.
1699 to 1703. Witislow, Sur une nouvelle valvula
de la venae cavae inferior, qui pent avoir rapport ;\
la circulation du sang dans le foetus : Mem. de
1'Acad. 1717. Eclaircissement sur un Mem. de
1717. Ibid. 1725. Hatter (Albert}, De Valvula
Eustachii, Gotting. 1737, et in Disp. Anat. torn. ii.
1747. Brendelius, De valvula venae cavae, Wit-
temberg, 1738 ; reprinted in Opusc. Math, et Med.
Pars i. Lobstein (J. F.), De. Valvula Eustachii,
Strasbourgh, 1771. Sabatier, in Mem. de 1'Acad.
1774. Wolff, De foramine ovali, &c. in Nova
Comment. Petropol. t. xx. Kilian, Kreislauf im
Kinde, &c. Karlsmhe, 1826. Biel (Guti.), De
foraminis ovalis et ductus arteriosi mutationibus,
1827. Berlin. Jeffray, Peculiarities of the foetal
circulation, Glasgow. 1834. Edinb. Med. andSurg.
Journ. 1835.

On the sounds of the heart. — Laennec, Traite de
1'Auscuhation Mediate, &c. Paris, 1819. Forbes's
translation, 4th edit. 1834. Turner (John W.),
3vol. Med.-Chirurg. Trans. Edinb. 1828. Wil-
liams ( T)r. David), Edinb. Med. and Surg. Journ.
vol. xx'xii. 1829. Corrigan, Dublin Med. Transact,
vol. i. 1&30. Stokes and Hart, Edin. Med. and
Surg. Journ. 1830. Spittal (Dr. R.), Treatise on
Auscultation, Edinb. 1830. Rouanet, Journal Heb-
dom. No. 97. Pigeaux, Journal Hebdom. torn. ;ii.
p. 239, et torn. v. p. 187, for 1831, et Archiv.
Gen. de Med. Juillet et Novembre, 1832. Billing,
Lancet, May, 1832. Hope, A Treatise on Dis-
eases of the Heart and great Bloodvessels, 1st edit.
1832. Appendix to 2d edit. 1835. Bryan, Lancet,
Sept. 1833. Piorry, Archiv. Gen. de Med. Juin,
1834. Newbigging ( Dr. P. S. K.), Inaugural Dis-
sertation on the impulse and sounds of The heart,
Edin. 1834. Carlile, Dublin Journal of Medical
Science, vol. iv. 1834, and Transact, of British
Scient. Assoc. vol. iii. 1834. Magendie, Lancet,
Feb. 1835. Medical Gazette, vol. xiv. Bmtillaud,
Traite clinique des maladies du cceur, torn. i. 1835.
Williams (Dr. C.J.B.), The Pathology and Diag-
nosis of Diseases of the Chest, 3d edit. 1835, and
Medical Gazette, Sept. 1835. Report of Dublin
Committee for investigating the sounds ' of the
Heart, Dublin Journal of Medical and Chemical
Science, Sept. 1835, and Transactions of British
Scient. Assoc. vol. v. Beau, Lancet, Feb. 1836.
Spittal (Dr. R.), Edin. Med and Surg. Journal,
July, 1836. Reports of the London and Dublin
Committees for investigating the sounds of the
heart. Transactions of British Scientific Asso-
ciation, vol. vi. 1837.

(John Reid.)

ON THE ARRANGEMENT OF THE
FIBRES OF THE HEART.— [The Editor
hopes that the following detailed account of
the researches of Mr. Searle on this difficult
point of minute anatomy will not be deemed
unacceptable. Any reference to the labours of
other anatomists has been rendered unnecessary
in consequence of that part of the preceding
article which bears upon this subject.]

Preliminary remarks. — In order to unravel
the fibres composing the ventricles of the heart,
considerable preparation is necessary. The
auricles, fat, coronary vessels, and external pro-
per membrane should be cleanly dissected off;
the heart should then be boiled thoroughly, but
not too much, so as to give its fibres the requi-
site degree of firmness without rendering them
fragile. For example : sheep's hearts should
be boiled ten or fifteen minutes ; calves' twenty

or thirty, and bullocks' forty or fifty minutes ;
immediately afterwards they should be im-
mersed in cold water ; for if they be exposed
to the air while hot, their superficial fibres be-
come dark, dry, and brittle. As the process of
unravelling occupies many hours, and as the
heart requires to be preserved in a good condi-
tion, it should be immersed during the intervals
in weak spirit and water. The heart of the calf
is preferable to that of any other animal, it
being on a scale which affords distinct views,
while the fibres of young are more easily sepa-
rated than those of older animals. The con-
formation is the same in all quadrupeds, and
bears a complete resemblance to that of the
human heart. When the coronary vessels are
dissected off, a depressed line or track is left on
the anterior and posterior surfaces of the heart.
Since this line corresponds externally to the
entire edge of the septum, and to the boundary
of the right ventricle, it may be usefully em-
ployed in reference to these parts. It is there-
fore denominated the anterior or posterior co-
ronary track, accordingly as it pertains to the
anterior or posterior surface of the heart.

The fibres of the heart are not connected
together by cellular tissue as are those of other
muscles, but by an interlacement which in
some parts is very intricate, and in others scarcely
perceptible. At the entire boundary of the right
ventricle they decussate, and become greatly
intermixed ; at the apex and base of the left
ventricle they twist sharply round each other,
and so become strongly embraced ; but in ge-
neral the interlacement is so slight that they
appear to run in parallel lines. Whether a
mere fasciculus or a considerable mass of this
last description of fibres be split in the direc-
tion of the fibres, a number of delicate parallel
fibres will present themselves, some being
stretched across the bottom of the fissure per-
fectly clean and free from any connecting medium
whatever; and although some must necessarily
be broken, yet these are so few that they do not
attract attention unless sought for. In this
process of separation very little resistance is
offered ; and none that is appreciable when a
single fibril is taken hold of by the forceps,
and stripped off, and which could not be done if
bound down by cellular membrane.

If a piece of common muscle be afterwards
split, it will be found to offer great resistance, and
to be attended with so much laceration of the
fibres, that instead of a beautiful series of fine
muscular threads arranged in parallel lines,
a ragged mass of mutilated fibres appears;
and during the process of separation, the cel-
lular substance is seen not only to connect the
fibres, but to afford the resistance which is ex-
perienced.

This comparison obtains in the undressed
state of the specimens ; but when cooked,
other distinctions are met with. For example :
in whatever direction a roasted heart be sliced,
its cut surface is uniformly smooth, not grained
like other muscles when dressed ; and it eats
short, not offering that elastic resistance which
other muscles do during mastication.

The absence of cellular substance as a con-

620

FIBRES OF THE HEART.
Fig. 278.

Fig. 279.

Fig. 280.

Fig. 281.

CPCAA

Fig. 282.

CPCAA^L

CACC

CRO

reeling medium among the fibres in question mined the fibres with me, could detect its exist-

is not only proved by the absence of its physi- ence.

cal characters, but by its not being discovered Since the chief utility of cellular membrane

through the medium of the microscope. Nei- in investing and connecting together the fibres

ther Mr. Kiernan nor Mr. Goadby, who exa- of a muscle is, most probably, that of retaining

FIBRES OF THE HEART.

621

them within their proper spheres of action,
and since the fibres of the heart are devoid of
this agent, the question arises as to what other
retaining power these possess. On this head
no difficulty presents itself; for the fibres, in
winding round and round the cavity of the left
ventricle, become arranged in concentric layers ;
and in taking a larger sweep, in surrounding
the right ventricle, the same arrangement is
preserved, so that during the systole of the
heart the whole mass of the fibres firmly com-
press each other, which necessarily retains them
all within their proper spheres of action, ex-
cepting the superficial fibres, of which those
towards the base, and especially those upon the
right ventricle, where there is great latitude of
motion, do not, preserve a parallelism with their
subjacent fibres, but lie nearly at right angles
with them. It is on this account, most proba-
bly, that the superficial fibres have attracted
notice, and have been viewed as a distinct
layer.

The disposition of the fibres varies in diffe-
rent parts of the heart, forming parallel lines,
angles, decussations, flat and spiral twists. The
fibres are arranged in fasciculi, bands, layers,
and a rope, which are so entwined together as
to form the two chambers called the right and
left ventricles. These are lined with their in-
ternal proper membrane.

The fasciculi are connected with the aorta,
pulmonary artery, and carneae columnae, and
contribute to the formation of the bands.

The bands. — By tracing the fibres in bands,
we are enabled to develop the formation of the
ventricles in a progressive and systematic man-
ner. The bands spring from a mass of fibres
which forms the apicial part of the left ventricle,
and which, in winding round just above the
apex of the heart, separates into two bands to
form the right ventricle.

It will render the demonstration more intel-
ligible if a preliminary and cursory view be
taken of the general course of these bands
(Jig- 283, p. 626,) by referring to the diagram.
The bands, as there given, form a mere
skeleton of the heart, merely indicating the se-
veral courses they take. The average width of
the bands is not less than a third of the extent
between the apex and base of the left ventricle.
In the diagram, cue indicates the winding of
a considerable mass of fibres just above the
apex ; at the septum, s, it splits into two bands.
The shorter, CACC, encircles spirally both
ventricles, one half round the right, the other
round the left ventricle. The longer band de-
scribes two circles : it first passes through
the septum, round the left ventricle marked
CPCA ; it secondly passes round the base, and
includes both ventricles in its circuit, marked
progressively CPCAA,CPCAAA, CPCAAAAC, and
RR.

After employing so many letters, it is requi-
site to explain that as the bands are frequently
receiving fresh accessions of fibres, it is desira-
ble to characterise those increments individually
by the initials of the names of the respective
sources from which they are derived ; and in
order to make a distinction between the indica-

tions of the fibres and of their respective origins,
the latter are characterised by double, and the
former by single initials. Accordingly, the
aorta, the pulmonary artery, the rope, and the
carneae columnae are designated AA, PP, RR,
and cc, while their fibres are marked A, p, R,
and c. This plan is modified in one instance
only, viz., the fibres of the main bulk of the
heart, being derived from the rope and the two
carneae columnae of the left ventricle, are desig-
nated in the first instance by their proper ini-
tials CRC ; but as numerous increments of
fibres are being made, in succession, to these
three original sets, it is convenient to make an
abbreviation in the lettering ; thus, CRC is in-
dicated by C large, when combined with
other initials; accordingly, CRCA is con-
tracted to CA, and CRCPCA to CPCA, and so
with the rest.

The layers. — Although the heart admits of
being split into a number of layers, yet there
being no material division formed by fasciae or
condensed cellular membrane, such separations
are strictly arbitrary. It is, however, found
convenient to separate the fibres into certain
layers, in order to give a methodical de-
monstration of the formation of this organ.
The same remarks obtain regarding the bands.

It is generally supposed that the superficial
fibres properly constitute a distinct layer, form-
ing a common sac, which encloses the two
ventricles. This is not strictly the case, for it
has the same origins and terminations as have the
fibres immediately subjacent to it. Neverthe-
less, the superficial fibres are, in the following
description, considered as a separate layer, to
show the peculiar construction of the apex.

The rope. — It has already been stated that
the longer of the two bands terminates at the
base in the rope. The fibres of this band, in
forming the brim of the left ventricle, make a
sharp twist like those of a rope, by which
means they become the inner fibres of this
chamber, and expand into a layer which enters
largely into the formation of the mass which
divides into the two bands. So the principal
band, although it receives several increments of
fibres, has no complete beginning nor ending,
a considerable portion of it originating and ter-
minating in itself, which circumstance renders
it necessary to fix upon the most convenient
part of its course for the commencement of the
demonstration.

Although the system here adopted of unra-
velling the fibres of the heart be strictly arbi-
trary, as every other must be, yet it will, most
probably, be found the only method by which
all the various courses, and several connexions
made by the fibres in forming the heart, could
be displayed.

The demonstration. — It is requisite to pur-
sue two methods of demonstration ; — one, de-
scribing the dissection, or unfolding, which
consists in unravelling and separating the fibres,
and tracing, from the circumference to the cen-
tre of the heart, their various courses, in the
form of bands, by which they become in order
unwound, and by which a general view of the
formation of the two ventricles is at the

622

FIBRES OF THE HEART.

same time presented. The other, describing
the formation, or winding up of the fibres,
comprehends the retracing of the fibres from
the centre to the circumference, showing their
respective origins, associations, courses, con-
nexions, and terminations, also the manner in
which they are wound up to form the two ven-
tricles into one compact conical body.

The dissection. — The first stage consists in
separating the superficial fibres from the two
ventricles, which, perhaps, cannot be accom-
plished in a more simple manner than by rais-
ing them in the forms of two wings and a tail,
as represented in Jig. 279, which is to be done
by commencing at the anterior coronary track,
cutting through the superficial fibres and de-
taching them by means of a blunt scalpel in
their natural direction, so far as their insertions
at the base ; this will be found to divest the
right ventricle, and, from their obliquity, a part
of the left. (See the left wing, CACC.) Then
recommencing at the anterior coronary track,
the fibres should be separated in the contrary
direction, over the left ventricle towards the
apex. These fibres take a very spiral course,
and as they approach the apex converge, but
on reaching it they twist sharply round upon
themselves, like the fibres of a thick cord, and
entering at the apex become the internal fibres
of this chamber. The remaining part of the
superficial fibres, extending from the apex to
the base, pertains exclusively to the left ventri-
cle; these should be divided an inch or two
above the apex, and the apicial portion detach-
ed, which will complete the tail, CRC. Its
fibres are represented, as they appear after sepa-
ration, untwisted. The basial portion of these
fibres should now be detached so far as the
annulus arteriosus, and reflected like the right
wing, CRC. These, as do most other fibres
which approach the base, take a more longitu-
dinal course, and in general they become so
separated as they diverge to encompass the
basial part of the heart, that they cannot be
raised in an entire layer unless some of the
subjacent fibres be taken with them.

The second stage of the dissection comprises
the disconnecting the bands which compose the
outer or proper wall of the right ventricle.
The superficial layer of fibres having been re-
moved, there remain two other layers pertain-
ing to this wall of the ventricle, viz. the middle
and the internal. The middle is separable into
two bands, the upper or basial, and the lower
or apicial. It is better to detach the apicial
band first, which makes one spiral circle round
the heart. Its outer extremity being attached
to the root of the aorta at its anterior face, and
sometimes to the pulmonary artery also, an in-
cision should be made extending from the up-
per part of the anterior coronary track obliquely
towards the annulus arteriosus, which incision
should, in a calf's heart, be a little more than
an inch in length and a tenth of an inch in
depth. The band should then be detached
agreeably to its spiral course from the base and
middle third of the left, and from the lower half
of the right ventricle, as far as the anterior co-
ronary track, the line from which the separation

commenced. It here receives on its posterior
surface a considerable accession of fibres from
the right surface of the septum, by the junction
of which this part of the boundary of the ven-
tricle is formed, but the further separation of
the band prevented, \v\fig. 281, in the first or
basial part of its course it is indistinctly seen,
marked CACC. In. fig. 282 its middle course
may be traced, although the half circle of the
band which wound round the left ventricle has
been cut off. In the preparation exhibited in
this figure the separation of this band could not
be effected under the posterior coronary track,
on account of the separation having been con-
ducted too deeply, where the fibres decussate
to form the posterior boundary of the right ven-
tricle. In Jig. 281, which exhibits a dissection
of the right ventricle of a bullock's heart, the
whole of the band, CACC, is separated as far
as the anterior boundary of this cavity, and lies
extended; and the accession of fibres it re-
ceives from the right surface of the septum are
seen prolonged into it.

The basial band crosses the upper half of
this ventricle. It cannot be raised from its
situation on account of the numerous lateral
connexions it forms in its progress with the
margins of the orifices of the aorta, pulmonary
artery, and annulus venosus. In order to de-
tach it as far as it will admit, an incision about
half an inch on the right side of and parallel
with the anterior coronary track, should be
made, extending from its lower edge to the
base, and an eighth of an inch in depth, or as
deep as will expose the fibres from the pulmo-
nary arteiy, which in general pass at an angle
with those of the band. Although this band
cannot be disconnected from the base, it can in
general be detached from the fibres of the sub-
jacent layer, so far as the posterior coronary
track ; sometimes, however, they are too inter-
woven to admit of any separation. The first
part of this band is represented in Jig. 281,
marked CPCAA; it was divided more than
half an inch from the anterior coronary track.
Its continuation may be seen in ^.282, lettered
CPCAAA, where it is evidently not discon-
nected from, but merely raised towards
the base, and if replaced would overlap the
fibres taking the middle course round the heart.
The depression at the line of the posterior coro-
nary track, pet, is occasioned by the band being
bound down at the base and at its under sur-
face also, by which means the upper half of the
posterior boundary of this ventricle is formed.
As the further pursuit of this band pertains to
the third stage, it will be made hereafter.

The internal layer. By the separation of
the two former bands the internal layer is ex-
posed. It is composed of fibres from the pul-
monary artery and from one of the carnea co-
lumnse. In Jig. 281 the fibres, PC, are seen,
arising from the root of the pulmonary artery at
its entire circumference, first forming a channel
and then expanding into a layer, which, in pro-
ceeding obliquely across the cavity, obtains an
accession of fibres from one of the carneoe co-
lumnae, which is not brought into view, and
which, on reaching the line of the posterior

FIBRES OF THE HEART.

623

coronary track, joins a band emerging from the
septum, and thus forms the apicial half of the
posterior boundary of this ventricle. It is
raised from its situation, but when replaced its
edge, which is everted by the probe, applies
itself to the anterior boundary of this cavity.
This layer cannot often be so extensively dis-
connected from its superjacent bands as this
figure represents.

The third stage of the dissection. — Having
separated the layers composing the right or
proper wall of the right ventricle, the next pro-
ceeding consists in detaching and unwinding
the band and layers composing the left ventri-
cle. First, the detachment of the basial band.
As this band has already been detached over
the right ventricle in the second stage of the
dissection, it is necessary to resume its separa-
tion at the posterior coronary track. But as
the further separation is somewhat difficult, it
will be rendered less so if the remaining portion
of this band be first examined in jig. 282,
wherein it is represented detached. When in
its natural situation it forms the uppermost
third of this, the left ventricle, and its lower
fibres overlap a part of those which occupy the
middle third. The fibres which overlap the
others in taking an oblique course towards the
base reach the brim of the ventricle and pass
over it, while the under fibres of this band are
appearing in succession, and taking a similar
spiral course until the whole bundle of fibres is
twisted in the form of a rope. In order, there-
forego trace out and detach this band as it becomes
transformed into a rope, it is requisite to com-
mence near the posterior coronary track (pet),
in a continuous line with the lower edge of its
former portion, introducing the handle of a
scalpel obliquely upwards so as to detach the
fibres which overlap those of the middle third,
and to carry the separation so far up as will
reach those marked A, coming obliquely down
from the aorta. In conducting this separation
from left to right it is soon found that the fibres
of this bundle, instead of overlapping others,
become themselves by twisting overlapped,
rendering it necessary, therefore, to turn gra-
dually the handle of the scalpel obliquely
downwards, tracing the rope according to its
windings. Two scalpels will be required in
conducting the further separation.

The next step should be preceded by viewing
the fibres of the rope in fig. 280, descending
and radiating into a layer which sweeps round
the cavity of this ventricle. The heart should
now be placed in a small cup or jar of a size
that will support it with its base upwards, and
then, with the scalpels employed vertically, the
separation should be proceeded with, and in
passing through the septum a vertical section
should be made through the aorta in the
line of separation, which should be pursued
round and round, and progressively deeper
until the handles of the scalpels perforate the
external fibres, which, if they have been rightly
inclined, they will do a little above the apex of
the left ventricle, just after they have completed
the division through the layers of the septum.
The band of fibres occupying the middle third

of the heart, and which now pass over the scal-
pels, should be divided; the incision being
made along the side of the posterior edge of
the septum. A section should be made through
the rope also, which allows the right ventricle
to be raised from the left, and the heart to be
unwound as far as the separation has been car-
ried. There yet remains a mass of fibres
around the cavity of the left ventricle to be de-
tached. This last process of separation should
be conducted in a contrary direction to that
which has hitherto been adopted, viz. from right
to left, until the internal membranous lining is
exposed, and which should be torn in order to
lay open this chamber.

The heart can now be unwound and extended
as in Jig. 278, placing the left ventricle, Iv, at
one end and the right at the other, removing
that section of the aorta, AA, connected to the
right ventricle from its counterpart which ex-
clusively pertains to the left, and which is hid-
den by the rope, RR ; removing also the two
portions of the bisected rope to the two most
distant diagonal points in this view. The
niche, CPC, indicates the part occupied by
the divided band which passed along the mid-
dle third of the heart.

The second method of demonstration. — The
formation, or winding up of the fibres,
of the heart. This description comprehends
the retracing of the fibres from the centre to
the circumference, showing their respective
origins, associations, courses, connexions, and
terminations, also the manner in which they
are wound up to form the two ventricles into
one compact conical body.

The first stage consists in retracing the su-
perficial layer from its origins to its termina-
tions. It is necessary to commence at the
very centre of the heart — the interior of the left
ventricle, whence spring the fibres composing
its main bulk. Fig. 278, at its right extremity,
exhibits the left ventricle, Iv9 laid open, exposing
the two carneae columnae, cc and cc, one of
which is placed out of its situation, in order to
show the interior of the chamber. The fibres
of the two carneae columnae, cc and cc, ex-
pand in a fan-like manner ; those of the rope,
RR, expand in a similar manner ; the radiated
fibres of each of these three bodies wind round
the axis of this ventricle forming its parietes ;
and as they wind so as to form an inverted
cone, it is clear that the inmost fibres alone
can reach the apex. Accordingly, a fasciculus
of the inmost fibres from each of these three
bodies, marked c, R, and c respectively, pass
down to the apex associated together, and in
their course make a gentle twist from left to
right, gradually contracting the cavity to a
point and closing it ; they then twist sharply
round upon each other and complete the apex
marked CRC conjointly, so that by means of
this twisting the internal fibres are rendered
external. These excluded fibres now enter into
the formation of the superficial layer, and form
the tail of Jig. 279. They take a very spiral
course near the apicial part, and over the an-
terior surface of the left ventricle as far as the
anterior coronary track ; but as they approach

624

FIBRES OF THE HEART.

the base, pass more longitudinally. It is evi-
dent that these few fibres would be inadequate
to form a complete layer, unless in their pro-
longation they pursued an uniformly spiral
course. They are more than enough to cover
the apicial part as they twist over each other;
but in consequence of the conical form of the
heart they soon become singly arranged, and
as they diverge, separate and leave interspaces,
some of which are occupied by fibres which
apparently arise abruptly at the surface. The
fibres which pass longitudinally to the base of
the left ventricle are inserted into the tendinous
margin of the annulus arteriosus, and into the
posterior part of the root of the aorta, forming
the right wing, cue. The spiral fibres have
been stated to arrive at the anterior coronary
track along its whole length. The majority of
them terminate at the coronary vessels ; others
are merely intersected by them, while others
pass under these vessels and become super-
ficial again : those which maintain their course
over the right ventricle vary in different hearts
from a small to a considerable number. Along
the whole length of this track accessory fibres
from the interior of the right ventricle are
emerging to associate with these in their way
over this ventricle. They take a longitudinal
course to the base, and therefore start at an
angle with the spiral fibres which are on the
left side of the coronary track. In Jig. 281
these accessory fibres from the aorta, A A, and
from two of the carneae columns?, are seen
passing together obliquely down the right sur-
face of the septum, marked ACC, to enter
into the formation of the extended band.
These accessory fibres perforate it along the
anterior boundary, ab, and become super-
ficial. This layer is, accordingly, in Jig. 279,
marked CACC; its fibres pass at nearly right
angles with the subjacent fibres, and when
raised form the left wing; its insertions are
the anterior part of the root of the aorta, the
tendinous margin of the annulus venosus, and
again the right part of the root of the aorta.
Sometimes festoons are formed at the base by
communications of fibres between the pulmo-
nary artery and the aorta, at its right and pos-
terior aspects.

It occasionally happens that the accessory
fibres which arise from the interior of the right
ventricle are not very numerous; in such cases
a greater number of fibres arise abruptly from
its surface.

The superficial layer has three sets of ori-
gins : one, primitive, from the interior of the
left ventricle; the others, accessory, from the
interior of the right ventricle, and from the
outer surface of both. It cannot with pro-
priety be considered as one common invest-
ment, since each ventricle for the most part
gives birth to its own superficial fibres. It is
necessary to raise it as a distinct layer for two
reasons : first, that the superficial fibres of
the right ventricle in general pass nearly at right
angles with their subjacent fibres, and there-
fore require to be removed in order to proceed
with the next stage of separation : secondly,
that it developes the peculiar mode of closing

the left ventricle, and of forming the apex;
and probably no other method than that of the
twisting of the fibres could have been so secure,
especially as the parietes at the apex of the
ventricle do not generally, even in a bullock's
heart, exceed a tenth of an inch in thickness.

The second stage — The external layer having
been traced from its origins to its insertions,
we may now trace the deep-seated layers ; and
as these have, for the most part, the same
origins, courses, and insertions as the super-
ficial layer, we may commence the description
at the same points.

It has been already stated that the fibres of
the rope and of the two earner columnae ex-
pand in a fan-like manner, that their inmost
fibres pass through the apex and become ex-
ternal, but that the chief of them wind round
the axis of the left ventricle above the apex,
as exemplified in fig. 279, cue. The respec-
tive sets of fibres pertaining to these three
bodies continue separate during their radiation
only, after which they become plaited together
by folding one over the others. Their mode
of association is shown in the extended portion
of the split layer, cue in fig. 280, also in
its counterpart, CRC, winding round the api-
cial part of the ventricle. Again, in fig. 278,
it may be seen that the fibres at the bases of
these columns turn under and pass up in con-
junction with those of the rope forming the
middle mass, cue, at the upper of which
they fold over making flat twists upon them-
selves, which have, however, become exag-
gerated in appearance by the unwinding of the
heart, as in rolling it up again some of the
angles are converted into spires, preserving a
considerable degree of parallelism.

Having shown the origins, and the method
adopted in the association, of the fibres form-
ing the middle mass in Jig. 278, we proceed by
tracing the divisions and prolongations of its
fibres, and the plan of building up the two
chambers of the heart. First, the forma-
tion of the left ventricle. If the right carnea
columna, cc, be replaced in contact with i's
fellow, and if the rope, RR, be brought
round the upper part of this cavity so as to
embrace them, and if portion 4 be split from
the middle mass, CRC, and be wound, in
association with the apicial fibres, CRC, round
the lower part of this cavity, that division of
the heart, comprising the left ventricle and the
middle mass, will bear a near resemblance to
that represented in fig. 280 ; in which figure
the rope, RR, in embracing the heads of the
carneae columnae, cc, brings into view its fan-
like fibres, R, sweeping round the upper part
of the axis of this ventricle ; in which the
fibres of portion 4, in winding round the lower
half of the axis, embrace the bodies of the
carnea? columnae, cc, and associate with the
apicial fibres, CRC, and in which the ex-
tended layer, CRC, represents the middle mass
minus the portion 4, which is split from it.
Thus much pertains exclusively to the descrip-
tion of the formation of the left ventricle.
That of the right is more complicated, and
constitutes —

FIBRES OP THE HEART.

625

Tht third stage. In pursuing the mass of
blended fibres, cue, occupying the middle
of Jig. 278, it is found that, after having formed
the left, it splits under the line marked by
stars into two bands, which embrace and con-
tribute to form the right ventricle. These sepa-
rated bands were stated in the preliminary
remarks to be of unequal lengths, the longer
making two and the shorter making but one
spiral circle round the heart. The longer, in
the first place, assumes the character of a layer
and forms the middle layer of the septum.
It requires to be described in three portions.
Portion 1, being attached to the valve of the
other section of the aorta, was stripped off in
unwinding the heart ; in the wound-up state it
passes over the pulmonary channel of fibres, p,
along the part marked 1, in its way to the
aorta, A A ; its absence, however, opens to
view the fibres coining from the base and form-
ing the right layer of the septum. Portion 2
proceeds from the starred line across to enter
into the formation of the rope, RII, and will
be noticed hereafter. Portion 3 is the longer
band; it is not entirely seen, being overlapped
by some of the fibres of portion 4 ; it passes
across to the niche, CPC, where it was di-
vided in unwinding the heart, in order to
liberate the two ventricles which were encircled
together by this band. Previously to pursuing
this band further, it is better to trace it as the
middle layer of the septum in its natural situ-
ation— the wound-up state of the heart. In
Jig. 280 it forms the extended layer, cue, in
association with portion 2, and split from por-
tion 4, which does not belong to the septum ;
on being replaced, its cut edge, a, applies to
the cut edge, 6, in passing as the middle layer
between the right and left layers of the septum.
The middle layer is seen in Jig. 282 emerging
at the posterior edge of the septum, where
portion 2 disconnects itself to join at the under
surface the band above, but in this figure is
marked C large, indicating that it is derived
from this layer, which has hitherto been lettered
CRC. This layer, being now deprived of all
its other portions, will hereafter be considered
as a band, and it has already been explained
why it should be denominated the longer band.
This band in emerging at the posterior edge of
the septum is joined by another band of fibres,
which is seen in Jig. 281, forming part of the
internal layer of the proper wall of the right
ventricle; its fibres, PC, arise from the pul-
monary artery, pp, and from one of the
carneae colurnnae not in sight ; they cross ob-
liquely over this cavity to the posterior edge
of the septum to join the band in ques-
tion. By the intimate blending of the
fibres of these two bands the apicial half
of the posterior boundary of this ventricle is
constructed. The longer band, now aug-
mented, is lettered accordingly in Jig. 282,
CPC, and in proceeding soon receives at its
inner surface an accession of fibres, A, coming
down from the aorta. This band, CPCA, in
winding spirally from left to right round the
left ventricle along its middle third, gradually
approaches both the base and the surface : for

VOL. II.

when it arrives at the anterior edge of the sep-
tum it becomes the basial band, and having
been traced round the left under the right ven-
tricle, in making its second circle it passes over
that cavity. In Jig. 281 the commencement of
its second course is exhibited. It is bisected,
one portion, CPC A A, being held up by a
probe ; the other, at the anterior coronary track,
a c t, receives at its inner surface a fasciculus
of fibres, A, from the aorta, AA, and is also
lettered CPCAA. This fasciculus and por-
tion of the band form together a groove, by
winding over the pulmonary channel when
brought down into its place, and which toge-
ther form the basial part of the anterior boun-
dary of this cavity. This band in its progress
round this ventricle constitutes the basial band
of the middle layer of its proper wall, and
forms so many connexions with the base, that
to trace them all would be found a very com-
plicated piece of dissection ; it is, therefore,
deemed better to give a general description of
them. For instance, the aorta presents three
different aspects under which this band is con-
nected to it: the first, at the termination of the
anterior coronary track; the second, between
the pulmonary artery and the annulus venosus ;
and the third, between the annulus venosus and
the annulus arteriosus, or at the extremity of
the posterior coronary track. The aorta re-
ceives at each of these parts an insertion of
fibres from the outer surface of the band ; and
the band receives on its inner surface a fasci-
culus from the aorta. These reciprocal com-
munications occasion the band to be very firmly
bound down to the base, and to be arranged,
to a certain extent, into festoons. For each
of these accessions from the aorta, an addi-
tional A is added to the lettering of the band,
which is, accordingly, designated CPCA A A A.
As the band passes the annulus venosus, its
outer fibres by a gentle obliquity in their course
successively arrive at its tendinous margin,
into which they become inserted immediately
below those of the superficial layer, and
some proceeding still more deeply pass
under the tendinous margin into the ven-
tricle, and form the musculi pectinati.
In order to avoid repetition it may be here
remarked, that this part of the description ap-
plies to the annulus arteriosus also. The last
two accessions of fibres this band receives
should be traced, since they assist in the con-
struction of the posterior boundary of the right
ventricle. In Jig. 282 this band is seen in the
latter part of its course round the right ventri-
cle, marked CP< AAA; on reaching the pos-
terior coronary track, pet, it is joined on its
inner surface by two fasciculi which bind it
down to the base, but on each side of this
track it is separated and raised. One of these
fasciculi, the last derived from the aorta, is
not seen in this figure ; the other appears emer-
ging from under this ventricle, being portion 2
of the middle layer of the septum, which
disconnected itself from this band, CPC, in
its first circle round the left ventricle ; it is
marked C large, being derived from the middle
mass of fibres, CRC, in fg. 278, in which

2 T

626

FIBRES OF THE HEART.

portion 2 is seen crossing over to join the band
CPCAAAAC, just before it becomes the rope ;
the fasciculus of fibres A from the aorta A A
is also seen joining this band at its inner sur-
face nearer the base. By the union of these
two fasciculi with the band in question, the
basial half of the posterior boundary of the
right ventricle is formed. By pursuing, in
jig. 282, this band or combination of fibres,
'lettered CPCAAAAC, it is seen to form, while
it is gradually twisting upon itself, the brim
of the left ventricle, and then to make a
sharp twist of its fibres into the rope R R, by
which means they are rendered the internal
fibres of the left ventricle ; in Jig. 280 they
may be traced expanding again into a layer,
pursuing the same spiral sweep from left to
right, but from the base towards the apex, and
inwardly instead of outwardly. Thus the de-
monstration brings us back to our starting-point.

We have yet to trace the shorter of the two
bands which originate in the splitting of the
middle mass of fibres, CRC, in fig. 278, to
embrace the right ventricle. This view ex-
hibits only the inner fibres of this mass as they
are prolonged into the inner or longer of the
two bands; but fig. 281 affords an outer view
of this mass of fibres as they are prolonged
into the outer or shorter band. They are seen
winding spirally up from the apex marked
CRC, and at the anterior coronary track, act,
they split, in the form of a band, from the
general mass to pass over the lower half of the
cavity of the right ventricle. In this figure
this band is separated and left extended, in
order that the accessions of fibres it receives
from the right surface of the septum may be
seen, which are the fibres A from the aorta
A A, and the fibres c and c form two of the
carneae columnse (not in view) passing obliquely
down from right to left to the anterior edge of
the septum, from which they extend into the
band which is lettered CACC, and unite in-
timately with its fibres. When the band is
replaced in its course over the ventricle, its
accessory fibres are made to reflect at an acute
angle upon themselves, and thus form the
apicial part of its anterior boundary. This
band describes one spiral circle round the heart,
arriving again at the anterior coronary track at
its basial extremity; it is inserted into the
aorta, and if the fibres make a very oblique
approach to the base, they will be also inserted
into the tendinous margin of the annulus arte-
riosus. The continuation of this band round
the posterior side of the heart can be traced in
Jig. 279. Its width is equal to about a third
of the heart's axis; it is seen marked CACC
in its spiral ascent from left to right, passing,
first,a little below the middle third of the heart;
at the posterior coronary track, pet, becom-
ing the middle third, and afterwards approach-
ing gradually the base in its way to its points
of insertion before-mentioned.

As the tracing the fibres from the circum-
ference to the centre, and from the centre to
the circumference, is a matter of much difficulty,
and as the description has been attended with
much detail, it is desirable that a more general

and concise view by means of a diagram should
be afforded of the courses which the fibres take
in constructing this organ.

RECAPITULATION. (Vid.thediagram/g.283.)
We commence tracing the fibres of the heart
from its very centre. The fibres, cc, from the two
carnese columnae of the left ventricle, LV, are
joined by the fibres, R, from the rope RR,
after those fibres of the rope have expanded
and formed the internal layer of the septum S ;
in winding round the axis of this cavity they
blend together as the initial letters CRC indi-
cate. The inmost of these fibres descend as far
as the apex, where they twist sharply round and
close the cavity, by which means they construct
the apex, and become the superficial fibres of
the heart. But the chief bulk of this mass of
blended fibres makes a spiral sweep from left
to right round the axis above the apex ; and when
it has described two circles, CRC, it splits at
the anterior edge of the septum into two bands,
one being considerably longer than the other.
The longer first makes one circle round the left
ventricle, then another, enclosing both ventri-
cles. In making the first circle it passes
through the septum forming its middle layer,
and on reaching its posterior edge itreceives from
the pulmonary artery accessory fibres, which
have crossed over the cavity of the right ven-
tricle, forming the inmost layer of its right or
proper wall, and fibres from one of the carnese
columnae of this ventricle, and from the aorta,
being marked CPCA. The accessory fibres
are not represented, as they would have ren-
dered the diagram complicated and unintelligi-
ble ; but they are indicated by their initials
being added in the lettering of the bands.
This band in question may now be traced
round the middle third of the left ventricle
advancing towards both the base and the outer
surface of the heart; on completing its first

Fig. 283.

FIBRES OF THE HEART.

627

circle it arrives again at the anterior edge of
the septum, receives another fasciculus of fibres
from the aorta, and is marked CPCAA. It
is then seen to take its course round the base
and in front of the right ventricle. As it passes
by the right aspect of the aorta, it again receives
from it a fasciculus of fibres, and is lettered
CPCAA A ; on reaching the posterior edge
of the septum, it is further augmented by two
accessions of fibres, one from the aorta at its
posterior aspect, and the other from the middle
layer of the septum. This combination of
fibres from various sources is indicated by the
combination of their initial letters, CPCAAAAC.
It should be borne in mind that C large
is the synalepha of CRC — the initials of the
primitive mass of blended fibres. This band,
in passing along the base of the left ventricle,
makes at first a gentle twist of its fibres form-
ing the brim of this chamber; it afterwards
makes a sharp twist and assumes the form of a
rope, by which means its fibres are transferred
to the interior of the ventricle. In descending
this chamber, they expand again into a layer,
and wind spirally round its cavity, first forming
the internal layer, R, of the septum, and then
associating with the expanded fibres of the two
carneae columnae, and thus arrive at the points
from which we commenced tracing them. We
now return to the anterior edge of the septum,
S, in order to trace the shorter band. At this
part the primitive mass of blended fibres splits
into two bands : the longer passes behind the
right ventricle through the septum as already
described ; the shorter passes in front. The
shorter first receives a considerable accession
of fibres from the right surface of the septum,
which pass down from the aorta, and from the
two carneae columnae springing from this sur-
face : it is lettered CACC ; it describes one
spiral circle round both ventricles. It first
passes over the lower half of the right ventri-
cle, forming the apicial band of the middle
layer of its proper wall, and then round the
left ventricle in an oblique direction to the base,
and terminates at the aorta near the anterior
coronary track, having completed its spiral
circle round the heart.

As the demonstration has, in reference to the
construction of the septum and of the right
ventricle, been unavoidably disconnected, it is
requisite to give a more systematic and com-
prehensive description of their particular for-
mation.

The septum is composed of three layers : a
left, a middle, and a right layer. The two
former properly belong to the left ventricle ;
and the last or right layer exclusively pertains
to the right ventricle. The two former are
composed of the primitive mass of fibres de-
rived from the rope and the carneae columnae of
the left ventricle ; the left layer being formed
of the expanded fibres, R, of the rope, RRj^rg^SO,
in their first sweep round the cavity ; and the
middle layer of the continued fibres of the
rope in its second sweep, blended with the ex-
panded fibres of the two carneae columnae.
These blended fibres form the extended layer
CRC ; its cut edge a applies itself to the cut

edge b, evidently forming the middle layer of
the septum. The last or right layer of the
septum has not the same origins as the two
former have. Its fibres arise from the root
and lower margin of the valve of that section
of the aorta which pertains to the right ven-
tricle, from that part of the root of the pulmo-
nary artery contiguous to the aorta, and from
the carneae columnae of the right surface of the
septum. The fibres attached to the aorta and
pulmonary artery may be seen in Jig. 278, lettered
A and R respectively, and infg. 280 the fibres
from the aorta blended with those of the car-
neae columnae are exhibited marked ACC,
forming the right layer of the septum.

The rig/it ventricle. — Although the right layer
of the septum belongs anatomically to the right
ventricle, yet when functionally considered it
pertains, as well as the other layers, entirely to
the left. For the concavity of this layer is,
like that of the other layers of the septum, to-
wards the cavity of the left ventricle, and
therefore during the systole approaches the axis
of this cavity, while it recedes from that of the
right ventricle ; thereby assisting in the propul-
sion of the blood from the former, and to a
limited extent counteracting the propulsive effort
of the latter ventricle.

The right ventricle has, therefore, but one
proper wall, which is connected to the left
ventricle in a manner to be described hereafter.
The right chamber should be divided into three
channels : the auricular, the pulmonary or
ventricular, and the apicial. The auricular is
that which receives the blood directly from the
right auricle ; the pulmonary is that formed
by the fibres which arise from the root of the
pulmonary artery at its entire circumference :
in Jig. 278, the pulmonary artery, PP, and the
fibres, P, are seen turned a little upon their
axis, by which means the fibres are rendered
oblique, and the channel the more complete ;
and the apicial channel is that which forms the
channel of communication between the other
two, and which extends to the apex. The pro-
per wall is considered as having three layers,
the superficial, middle, and internal, although
they cannot always be detached from each
other. The superficial is composed of the
mere superficial fibres of this wall, having the
same origins and terminations as have its sub-
jacent fibres; it forms the left wing CACC of
Jig. 279. and may be seen in fg. 281, raised
from the right ventricle and reflected over the
base marked CACC. The middle layer is
composed of two bands, the apicial and the
basial. The apicial is formed of the first semi-
circular portion of the shorter band of the
heart, and passes over the lower half or apicial
channel of this chamber ; it lies separated and
extended over the apex of Jig. 281, marked
CACC. The basial band of this layer is
formed of the first semicircular portion of the
longer band as it makes its second circle round
the heart. It is bisected and separated as
seen at CPCAA, of Jig. 281; in its natural
situation it passes over the pulmonary and
auricular channels of this ventricle, and is
closely connected to the base. The internal

2x2

628

FIBRES OF THE HEART.

layer arises chiefly from the pulmonary artery,
PP ; it first forms the pulmonary channel, P,
and then expands into a layer which crosses
obliquely over the apicial channel, associated
with fibres derived from one of the carneae
columnae. The basial portion of this layer
which crosses over the auricular channel, can-
not often be separated from the fibres of its
superjacent band, the fibres of the musculi
pectinati being intricately interwoven with
them. When this layer is replaced, its lower
loose edge applies itself to the anterior boun-
dary, a b, of this cavity, and is lined with its
internal proper membrane. Of the three layers
composing the proper wall of this ventricle,
two, the middle and inner layers^, are confined
at the edge of the septum, forming thereby the
lateral boundary of this cavity.

The boundary of the right ventricle. — It is
true that every part of the internal surface of this
chamber contributes in forming its boundary.
But, as this cavity is formed chiefly by the
splitting of the mass of fibres into layers and
by their re-union, it is clear that unless the
layers so separated were well secured at their
points of junction, their separation would pro-
gressively increase, and the cavity enlarge to a
fatal extent by the repeated dilatations to which
it is subjected. The mode of union which
secures this lateral boundary merits therefore
particular notice. As the lateral boundary
corresponds to the edge of the septum, it admits
of the same division into anterior and posterior.
The anterior boundary being formed by the
splitting of the layers, and the posterior by their
re-union, their respective modes of construction
are not precisely similar. The anterior boun-
dary is principally formed by a certain set of
fibres winding and reflecting upon themselves,
as shewn in jig. 281. The basial part of this
boundary, a*6, is formed of fibres A, from the
aorta A A, winding over the pulmonary channel
of fibres p, in contributing to form the band
CPCAA. The fibres of this channel also con-
tribute to form this part of the boundary,
as is represented in Jig. 278. The apicial part
of this boundary is obviously constructed by
the fibres ACC which form the right layer of
the septum being prolonged into the extended
band, which on being replaced occasions them
to be doubled upon themselves in passing over
the apicial channel in association with the fibres
of this band.

The posterior boundary is constructed by
the re-union of the fibres which pass in front
of the cavity with others which pass behind it,
and by the attachment of some of the fibres at
the base to the aorta. The basial half of this
boundary being formed by the conjunction of
the under fibres of the basial band CPCAA A,
Jig. 282, with a fasciculus of fibres, c, emerging
from the middle layer of the septum, and with
another fasciculus of fibres, A, jig. 278, arising
from the aorta, AA. That part of the boundary
contiguous to the base is greatly strengthened
by the outer fibres of the basial band being
attached to the aorta at its posterior aspect.
And the apicial half of the posterior boundary
being formed by the conjunction of the prin-

cipal part of the internal layers of fibres which
cross obliquely the cavity of the right ventricle
with the chief part of the fibres of the middle
layer of the septum as they emerge at its pos-
terior edge, where they freely decussate. In
jig. 281 the internal layer of fibres, PC, is seen
crossing the cavity obliquely towards the apicial
part of the posterior boundary, and in jig- 282
their conjunction with the fibres which emerge
from the septum is seen forming a firm union.
But the lateral boundary is rendered doubly
secure by the curious circumstance of the
coronary vessels, deeply penetrating the sub-
stance of the heart along the entire edge of the
septum, stitching down, as it were, just on the
outside of the boundary, all the fibres which
form it.

The conical form of the heart. — The only
point now remaining for consideration is the
conical form of the heart. This form admits of
the following explanation. Along the central
cavity of the left ventricle are placed the two
carneae columnae, the length of which is equal
to the lower three-fourths of the length of the
axis of this cavity. The fibres of these two
bodies radiate, as represented in Jig. 278 ; and
the radiated fibres wind round the axis closely
upon them, as is seen in Jig. 280. By this
radiation, instead of all the fibres passing
longitudinally, which would have preserved
these bodies in a state of equal thickness
throughout their length, they are progressively
parting with their fibres, retaining but a few,
which, by their longitudinal course, reach the
apex; consequently these columns gradually
diminish, becoming pyramidal, and forming
together an inverted cone ; and as the fibres in
well-formed hearts wind closely round these
columns, the entire ventricle gently assumes
the form of a cone. And although the right
ventricle is, as it were, appended to the left,
yet it is not so connected to it as to destroy the
conical form, but, on the contrary, in such a
manner as to form a concave parabolic section
of a cone which adapts itself to the gentle cone
of the left ventricle. The two ventricles thus
united assume the form of the more rapid cone
of the heart.

Construction of the auricles. — For the pur-
pose of ascertaining the mode in which the
fibres form the auricles, large hearts, as those of
bullocks and horses, should be selected. Not-
withstanding the muscularity of the auricles is
very much greater in large than in small hearts,
yet the plan is the same in both, although less
developed in the latter.

The fibres of the auricles arise chiefly
from the tendinous margins of the annulus
venosus and annulus arteriosus ; they ascend
interiorly, and arrange themselves into several
columns, which give off branches. Some of the
branches form a simple communication between
two of the trunk-columns, but most of them
subramify, by which means the interstices are
filled in. In small, hearts the columns are not
only more slender, but more numerous and in-
terlaced ; in these, the interstices in many
places are not filled in, the internal and external
proper membranes being in contact, and thus

FIBRES OF THE HEART.

629

completing the wall. Fig. 284 affords an interior
view of a section of the right auricle, in which,

Fig. 284.

the lining membrane being removed, the fibres
are seen arising from the tendinous margin of
the annulus venosus AV, forming the internal
part of the wall of this auricle, and in their
progress up arranged into columns, c, the
branches of which are entwined together so as
to construct the appendix. These convo-
luted columns at the posterior aspect of the
appendices are flattened, as shown in fig. 285, c,
where their fibres are associating together, and

in passing round the edges to the anterior sur-
face become evenly arranged again, as seen in the
appendix A of the right auricle, RA, of Jig. 286.
Thus far the construction of the two auricles

agrees, the fibres of each arising from its respec-
tive annulus, forming first the inner part of the
wall of the auricle, and then being arranged
into columns which entwine together, forming
the whole of the appendix. The fibres of the
right auricle, after having formed the wall of
this cavity, are prolonged to form the outer part
of the wall of the left auricle. As may be seen

in Jig. 286, the fibres which extend from the con-
voluted fibres of the posterior surface of the
right auricle, RA, wind evenly arranged, some
over the apex, and others round the auricle,
marked c, completing the outer part of the wall
of the entire auricle : they then meet at the
septum S, across which they pass associated
together, marked D, and on reaching the left
auricle divide into an upper portion and an
anterior and posterior band. The upper portion
is composed of the continued fibres D, which
proceed up the appendix and encircle its apex,
The anterior band E winds round the left au-
ricle LA, and on reaching the root of the
aorta K, its fibres become more or less at-
tached to it in different hearts ; in its course
upwards, marked F, when it has completed a
circle it passes behind the fibres which form the
first part of the circle to enter into the formation
of the fleshy columns of the appendix. The
posterior band passes over the left auricle be-
tween the appendix A and the vena cava su-
perior cs ; and in Jig. 285 it can be traced,
coming over, marked c, and passing along the
posterior surface of this auricle LA, including
in its course the posterior edge of the appendix
A ; the fibres which pass along the posterior
edge of the appendix, on arriving at the ante-
rior edge, separate from the band G to pursue
their course round the edge of the appendix, —
now along the anterior edge, — and join the
fibres D, which cap the apex. This division
of the band which encircles the appendix is con-
stant, and evidently affords particular strength
to its edge. The band itself G winds down
towards the base, expanding and surrounding
the orifices of the pulmonary veins p; some
of its fibres become lost on the surface of the
auricle, and the others may be traced to the root
of the aorta.

This band cannot be completely detached in
consequence of some of its fibres being inter-
woven with its subjacent fibres.

The left auricle, without the addition of these
bands, would nearly balance in substance and
strength the right ; their addition gives, there-
fore, to the left a considerable preponderance
in these respects over the right auricle.

The septum S is, in Jig. 286, shown to;be com-
posed, superiorly, of the transverse band of
fibres D, which passes from the right to the
left auricle ; in its middle part, of the ascending
fibres H, which arise from the root of the aorta
K, and pass up behind the band p, some
joining this band, the others proceeding to the
vena cava superior cs ; and lastly, at the infe-
rior and posterior part, of a slender fasciculus
of fibres which crosses the septum transversely
between the root of the aorta K and the vena
cava inferior ci, extending from the annulus
venosus to the left auricle, but which cannot be
seen in this figure.

In concluding these remarks on the construc-
tion of the auricles, it may be mentioned that
in the hearts of large animals a great dirferenceex-
ists in the structure of the two venae cavae, the
superiorbeingparticularly fleshy, and the inferior
apparently devoid of muscularity.

(H. Searle.)

6,10

ABNORMAL CONDITIONS OF THE HEART.

HEART, ABNORMAL CONDITIONS

OF. — There is no organ in the body in which
the various deviations from the normal state have
been more diligently or more carefully explored
than the heart ; nor ought it to be otherwise,
when we take into account the important part
which the heart performs in the organism, and
the serious nature of the derangements which
its diseases in general produce, — how many or-
gans and how many functions are involved in
the break-up which too often follows the oc-
currence of morbid alterations of the heart.
The great frequency* of diseases of this organ,
and the manifest and tangible shape which these
diseases assume, as well as the little liability
of its component structures to those appearances
which have been denominated pseudo-morbid,
these circumstances render it comparatively
easy to detect and observe its abnormal condi-
tions. To one who has made the natural
condition of the whole organ, as well as of its
several parts, the subject of careful study,
there is no field of investigation in morbid
anatomy which presents fewer difficulties.

The records of anatomy are not without in-
stances of total absence of the central organ of
circulation (acardia); and it may well be
supposed that such cases would also afford
examples of the defective development of other
not less important organs. In short, it is in ace-
phalous and anencephalous foetuses that the heart
is most frequently wanting, although its ab-
sence is not, as some observers suppose, a con-
stant characteristic of these forms of monstro-
sity ; nor on the other hand does acardia ne-
cessarily imply acephalia or anencephalia.
Thus in the case recorded by Marriguesf, and
quoted at length in Breschet's Memoir Sur
I'Ectopie du Cceur,\ the brain was present, while
all the usual contents of the thorax were
wanting, their place having been supplied by
a large bladder full of clear water which occu-
pied the whole thoracic cavity. The details
of another case were communicated many
years ago to the Royal Society by Sir Benjamin
Brodie, and are published in the volume of
their Transactions for 1809. The foetus was
one of twins, as is most frequently the case
when the heart is absent. The brain was
" nearly the natural size, and nothing unusual
was observed in it." The heart, thymus gland,
and pleura were absent, and the lungs most
imperfectly developed. The aorta, however,
was tolerably perfectly developed, but as a con-
tinuation of the umbilical artery extending
from the left groin upwards on the fore-part of
the spine to the upper part of the thorax, where
it gave off the two subclavian, and afterwards
divided into the two carotid arteries without
forming an arch. The external and internal
iliac arteries of the left side came from this
artery in the left groin immediately after it left
the umbilicus, and the common iliac of the

* Out of 520 post-mortem inspections recorded
by Dr. Clendinning, 170 were cases of diseased
heart, or about 33 per cent. — Vide his Croonian
Lectures for 1838, Med. Gazette, vol. xvi. p. 657.

t Mem. de Mathem. pres. a 1'Acad. des Sc. t. iv.

$ Rep. Gen. d'Anat. et de Physiol. t. ii.

right was given off from it in the lumbar region
after it had gained the situation of the aorta.

We shall first examine the congenital devia-
tions from the normal state in this organ, and
secondly its morbid alterations.

I. Congenital abnormal conditions. — These
are observed under three heads. 1. Congeni-
tal aberrations of position, or ectopise of the
heart. 2. Malformations by defect in deve-
lopement. 3. Malformations by excess of de-
velopement.

1 . Congenital aberrations of position. — The
simplest form of malposition is that in which
the heart retains the vertical position which it
occupies during the early periods of intra-ute-
rine life ; but of this the authentic instances are
rare.* Better known is that deviation in which
the heart is directed downwards, forwards, and
to the right side. This malposition generally
occurs as a part of a universal transposition of
the abdominal and thoracic viscera, of which
many well-marked examples are now on re-
cord; however, it sometimes, although more
rarely, exists alone without ectopia of any
other organ. Breschetf records four cases of
this latter kind. OttoJ has met with three in-
stances, and many other examples are scattered
among the records of anatomists.§ In this
form of transposition of the heart, the aorta
sometimes passes down along the right side of
the spine, and at other times down its left side.
In the latter case the transposition is not so
complete, the ventricles retaining their natural
position with reference to the anterior and pos-
terior aspects of the body. Again the heart
may be pushed too much to the left side, as a
mechanical result of congenital diaphragmatic
hernia of the right side; and it has been
found laid across in the chest from one side to
the other, the apex being at one time directed
to the right side, and at another to the left,
or turned upside down, the base toward the
abdomen, or in that cavity, the apex upwards
still remaining in the thorax.

In such cases as have been just detailed,
the heart still retains its title to be considered
as a thoracic viscus ; but other and more re-
markable malpositions of it have been found,
where it is excluded from that cavity. These
are, in fact, congenital thoracic herniae in va-
rious directions, of which Breschet, whose
memoir already referred to contains the most
complete account of this subject, enumerates
three principal varieties, according to the situ-
ation in which the heart is found, viz. the
superior or cervical displacement, the abdo-
minal or inferior, and the thoracic or anterior.

Thus Breschet details a case in which the
heart, lungs, and thymus gland were all con-
tained in the anterior part of the neck, forming
a large tumour under the lower jaw. The
point of the heart was attached to the base of
the tongue, and placed between two branches
of the lower jaw. The thorax was occupied

* Sandifort, Obs. Anat. Path.

t Op. cit.

\ Self. Beobacht. part i, p. 95, and part ii. p. 47.

$ Reuss' Repertorium, vol. x. p. 90-91.

ABNORMAL CONDITIONS OF THE HEART.

631

by the abdominal viscera, which had passed
up through a fissure in the diaphragm. In a
second instance of this high displacement the
apex of the heart adhered to the palate; but in
this case the malposition appears to have been
owing to a morbid adhesion of the umbilical
cord to the head, by which all the viscera were
drawn out of their natural positions. A less
degree of cervical displacement is where the
heart is found immediately above the thorax,
in the front of the neck, which, however, is
very rare.

When the malposited heart is found in the
abdomen, the diaphragm is generally deficient
to a greater or less extent.

In a case narrated by Mr. Wilson,* the
heart was in a fissure on the convex surface of
the liver — the infant lived seven days ! Ramel
also gives an instance of the heart being placed
in the region of the stomach, and the indi-
vidual in whom he observed it was ten years
of age. And in the extraordinary case related
by Deschamps, the heart occupied the place of
the left kidney ! Not the least marvellous cir-
cumstance about this case is, that the indi-
vidual was an old soldier, who had served
several campaigns, and enjoyed excellent health,
with the exception of nephritic pains, which
ultimately procured him his discharge from the
service. The right kidney alone existed, and
was found in a state of suppu ration .f The
vessels emanating from the heart passed through
an opening in the diaphragm into the thorax.

Dr. Paget mentions some instances of vari-
eties of position which parts of the heart may
assume with respect to each other. In a case
recorded in the first volume of the Edinburgh
Medico-ChirurgicalTransactions by Dr.Holmes
of Canada, the right auricle, enlarged to the
capacity of a pint, was found to open into the
left ventricle in place of the right, into which,
however, the blood afterwards found its way
through a small perforation in the septum of the
ventricles.

The aorta and pulmonary artery may arise
from one ventricle alone, either right or left, and
instances of each preternatural origin are pre-
served in the museum of the Edinburgh Col-
lege of Surgeons.

When the anterior wall of the thorax is de-
ficient, the heart may be found protruding
through the opening, as in fissure of the ster-
num, or a defect in its inferior portion as well
as in some of the ribs; nor does this mal-
position necessarily destroy life. Where the
deficiency is not confined to the wall of the
thorax, but also extends to the abdomen, the
stomach, liver, and spleen, with the heart, are
found occupying a large hernial sac in front
of the opening, which is sometimes contained
in the sheath of the umbilical cord, or covered
by an extension of the common integument.
In the case of simple fissure of the sternum,
it has occurred that the heart had not protruded,
but occupied its natural position, being simply

* Phil. Trans. 1798.

t Quoted by Breschet from the Journ. Gen. dc
Med. t. xx vi.

exposed to view by the abnormal opening in
the chest.*

2. ]\Ial formations by defect in dcvelopewent.
— Our limits compel us to restrict the present
account to little more than an enumeration of
the congenital malformations which may be
placed in this class. In these malformations
we find a diminution in the normal number of
the heart's cavities, either from a very early
arrest in the developement of the whole organ,
or from a total non-developement of the sep-
tum, or from its imperfect developement. A
few rare instances, many of which have oc-
curred in the lower quadrupeds, of an ex-
tremely imperfect state of the heart, are quoted
by Otto, in which that organ seemed to consist
of nothing but a fleshy enlargement at the
commencement of the aorta, described as " a
mere fleshy mass without any cavity," or " a
longish solid mass from which the vessels arise,"
'* or a mere expanded vascular trunk."

The dicalious heart of Hunter, or that with
two cavities, exists at a very early period of the
developement of the Mammiferous embryo :
it is described and figured by Baer in the em-
bryo of a dog, of three weeks, only four lines
in length, as consisting of a single auricle and
a single ventricle.-}- The permanence of this
state of the heart, similar to the natural con-
dition of that organ in fishes, constitutes one
of the simplest but rarest malformations in the
human subject. From the ventricle a single
vessel arises which subdivides into the aorta
and pulmonary artery. A very perfect example
of this malformation is described by Mr. Wilson
in the Philosophical Transactions for 1798;
it is the same case which has been already al-
luded to as affording an instance of malposition.
In this case the blood was returned from the
lungs by two veins which joined the superior
vena cava, and entered the auricle along with
it, the inferior cava being formed in the usual
way. Other examples are recorded by Mr.
Standert,t Dr. Farre,§ Professor Mayer,|| and
Dr. Ramsbotham.^f

The heart with three cavities (tricoilia of
Hunter), that is, containing two auricles and
one ventricle, or that form of the heart which
belongs to the Batrachian reptiles, must be
very rare, if indeed it ever occurs.

A case is related by Breschet,** in which a

* The reader who desires farther information on
the congenital ectopia of the heart, may consult
Breschet's memoir already referred to ; Dr. Paget's
Inaugural Dissertation on Malformations of the
Heart, Ed. 1831 ; the article on Displacement of
the Heart, by my valued friend Dr. Townsend, in
the Cyclopaedia of Practical Medicine, vol. ii.;
Fleischman de vitiis congen. circa thoracem et
abdomen, Erlang. 1810; Weese de Ectopia Cordis,
Berol. 1819 ; and Haan de Ectopia Cordis, Bonn.
1825.

t De ovi Mammal, et Hominis Genesi ; also
in Forbes* Journal another case by Baer, vol. i.
plate 2, fig. 9, human embryo about the fifth
week.

J Phil. Trans. 1805.

6 On the Malformations of the Human Heart.

[j Arch. Gen. de Med. torn. xvii.

T| Lond. Med. and Phys. Journal.

** Rep. Gen. d'Anat. torn. ii.

632

ABNORMAL CONDITIONS OF THE HEART.

single ventricle and two auricles existed, but
along with an imperfect inter-auricular septum.
The two auricles, therefore, virtually formed
one cavity. A similar case is recorded by
Wolff,* and is remarkable from the fact that
the individual in whom it was observed lived
to the age of twenty-two. These hearts then
do not exactly correspond to the tripartite heart
of Batrachia, inasmuch as the two auricles
communicate. A similar case, shewn by Mr.
Lawrence to Dr. Farre,f explains more par-
ticularly the true nature of the malformation.
It was a deficiency of the septa, both auricular
and ventricular, the latter having been alto-
gether wanting ; the former consisting only of
a small muscular band, which left a large fora-
men ovale without a valve, but the venae cavae
and pulmonary veins opened into their respec-
tive auricles, which externally appeared to be
quite separate. The ventricle communicated with
the two auricles by a single ostium ventriculi,
and the aorta and pulmonary artery, the en-
trance of the latter being somewhat contracted,
arose side by side from the left part of the
ventricle.

/Most of the other defective malformations of
the heart consist in prseternatural communica-
tion between the right and left cavities, resulting
from various causes. 1. The communication is
direct,eitherfromanopen foramen ovale, orfrom
an imperfection in the septum of the auricles
or of the ventricles, or from the co-existence
of all three or any two of them. 2. The com-
munication is indirect, the septa being perfect,
but the ductus arteriosus remaining pervious.

The open foramen ovale is by far the most
common of all the malformations of the heart ;
numerous examples of it are now on record,
as found in persons of all ages. The opening
of communication varies considerably as to size,
apparently according to the period of develope-
ment at which the arrest took place; the di-
ameter of the opening ranges between two ancj,
twelve lines. We know that the size of this
orifice is inversely as the size of the foetus
during intra-uterine life, whence we may infer
that the larger the opening is, the earlier must
have been the period at which further deve-
lopement ceased. In many instances the valve-
like portions which bound this opening have
acquired their full developement, and the only
defect seems to be the non-adhesion of their
margins, so as to close the cavity ; this non-
adhesion again may involve the whole extent
of the margins of the valves, or only a very
small portion, thus leaving a large or small
opening of communication between the two
auricles. Such a condition of the iriter-auri-
cular septum does not necessarily occasion
that intermixture of the blood which so com-
monly accompanies the communication be-
tween the right and left cavities ; and where
the opening is small, of course this inter-
mixture is the less likely to occur. Thus every
anatomist must be aware that it is not an un-
frequerit occurrence to find an opening large

* In Kreysig's die Krankeit. Herz. B. iii.
t Loc. cit. p. 30.

enough to introduce a goose-quill in the hearts
of adults who during life exhibited no derange-
ment of the circulation, and who died of dis-
eases totally unconnected with the heart. On
the other hand we are often surprised at the
amazing size of the opening in the hearts of
persons who have lived many years, and have
shewn less disturbance of functions than the
freedom of the communications between the
auricles would warrant us to expect. In many
of these cases the absence or mildness of sym-
ptoms may be accounted for by the obliquity
of the passage of communication, and the
overlapping of the margins of the valves, so
that at times they completely oppose the flow
of the blood from one side of the heart to the
other, whilst, at other times the passage is left
more or less free. In a heart which I lately saw
in the Museum of Guy's Hospital, the circumfe-
rence of the open foramen ovale was equal to
that of a halfpenny, (i. e. about an inch in
diameter,) and yet the patient had lived to the
adult period; and in a case quoted by Dr.
Farre from Corvisart, the foramen ovale was
" more than one inch in diameter." Such cases
strongly favour the opinion that the foramen
undergoes considerable enlargement when once
all impediment to the passage of the current
of blood from one side to the other has been
removed.* More rarely we find the fossa
ovalis cribriform, and thus several small open-
ings of communication exist between the
auricles, and sometimes in addition to the un-
closed foramen ovale, we have a true imper-
fection in the septum, as in the case related by
Walter,f and another by Otto.J

Imperfection in the septum ventriculorum is
a much less frequent cause of the communi-
cation between the right and left hearts than
the open foramen ovale. The opem'Xg, varying
in diameter from two lines to about an inch,
is situated towards the base of the septum,
so that the ventricles communicate at their
bases ; a fact which evidently indicates that the
opening results from the progress of the de-
velopement of the septum being arrested near
its completion, since the base of the septum
is the last portion formed. The orifice of com-
munication generally opens upwards towards
the orifices of both arteries, and is bounded
inferiorly by the rounded smooth edge of the
ventricular septum. In these cases the aorta
opens into both ventricles and appears to arise
from both ; and frequently the orifice of the
pulmonary artery is contracted and more rarely
obliterated, either from non-developement or
from previous morbid action; moreover, ap-

* It is not, perhaps, correct to suppose every
case of open foramen ovale congenital ; at least
it is certain that many patients date their symptoms
from a fall or blow ; and even without any evi-
dence of the occurrence of such violence many
cases have been observed which can be explained
only by supposing that the foramen ovale had been
morbidly re-opened. See Aberncthy in Phil. Trans.
1798 ; Otto, Selt. Beobachtungeii ; and Pasqualini,
Memorie sulla frequente apertura del fora mine
ovale rinvenuta nei cadaveri dci tisici. Rom. 1827.

t Obsrrvat. Anatom.

$ Paihol. Anat. by South.

ABNORMAL CONDITIONS OF THE HEART.

633

parently as a consequence of this contracted
state of the arterial outlet of the right ventricle
the ductus arteriosus often remains open, which,
by its communication with the aorta, conveys
some blood into the pulmonary arteries from
that vessel ; and, as a further complication, the
right ventricle is very small and appears merely
as an appendage to the left ; sometimes also
the left auricle is very small, while the right is
much dilated.

Where so much complication exists, as that
just detailed, one is only surprised that vitality
can be at all supported after extra-uterine life
has commenced; yet we find that children with
hearts so malformed live three, four, or five
days, and even as many weeks or months;
but where the perforation of the septum is not
accompanied with the contracted state of the
pulmonary artery, life may be prolonged to a
considerable period. Thus, Louis quotes one
case of a general officer (age not stated), whose
death was occasioned by the active part he took
in the American war. Along with ossified
valves of the right auriculo-ventricular orifice,
there existed a perforation of the septum ven-
triculorum large enough to admit the extremity
of the little finger. In another case, quoted
from Richerand, the patient aged 40, the per-
foration of the septum was half an inch in
diameter.

We say that the two sides of the heart com-
municate indirectly when the ductus arteriosus
continues, as in its foetal state, to convey the
blood of the right heart into the aorta descen-
dens, where it becomes intermixed with the
blood of the left heart. But it is very rare to
find this condition existing alone, and when it
does so exist, the canal of communication is
generally very narrow. More frequently it is
complicated with a contracted state of the pul-
monary artery, the place of which it seems to
supply. In a case related by Mr. Howship,*
this vessel constituted, in fact, the trunk of
the pulmonary artery. The pulmonary artery
proper arose in its usual situation, but was
quite impervious at its root, though far beyond,
and terminated in a cul-de-sac beside the heart.
Similar cases are recorded by Dr. Farre. At
other times the ductus arteriosus is employed
to supply the place of the aorta descendens; the
aorta is perfect only as far as the termination
of its arch, where it contracts, and its con-
tinuation is formed by the ductus arteriosus,
through which the descending aorta receives
its whole supply of blood.f

A very perfect case of this kind is quoted
by Dr. PagetJ from Steidele. The aorta and
pulmonary artery arose as usual ; the aorta was
entirely distributed to the head and upper
extremities, while the pulmonary artery, after
giving off two branches to the lungs, con-
tinued as the aorta descendens without any
communication with the aorta ascendens.

Malformations of the valves. — A not un-
important class of defective malformations in

* Edin. Med. and Surg. J<u-n. vo1. ix.

t See Sir A. Cooper's CASCS in Farrc, loc. cit.

$ Loc. cit.

the heart consists of imperfections in the num-
ber or structure of the valves. The aorta may
have two valves only, one of which may retain
its natural form and size, while the other pre-
sents the appearance of having been formed
by the fusion of two valves ; it may therefore
present one or more openings in it, so as to
appear somewhat cribriform. A similar con-
dition is met with in the pulmonary artery,
when sometimes the three valves seem as it
were united to form one membrane, which like
a diaphragm stretches across the mouth of the
artery, and is perforated in the centre by an
opening through which the blood finds its way
into the artery. This narrowing of the orifice
of the pulmonary artery is the most frequent
of the congenital malformations of the valves :
we have already described it as a frequent con-
comitant of imperfect septum of the ventricles.
Congenital imperfections of the mitral and
tricuspid valves are of very rare occurrence.
The perforated or cribriform condition which
is frequently seen affecting these valves, the
Eustachian and Thebesian valves, and more
rarely the semilunar valves, is probably the
result of a morbid atrophy.

Congenital absence of the pericardium. —
Connected with the malformations by defect
of developement we may mention the con-
genital absence of the pericardium, which,
although very rare, rests on too strong evidence
to admit any further doubt of the possibility
of its occurrence. Most of the cases related
by the older authors weie in connexion with
displacement of the heart, and from the liabi-
lity of mistaking universal adhesion of the
pericardium for this congenital absence, many
anatomists, among whom was Haller, denied
that such a defect had ever existed.

Dr. Baillie* was the first of modern anato-
mists who accurately described a case of this
kind. " Upon opening," he says, " into
the cavity of the chest, in a man about forty
years of age, in order to explain at lecture the
situation of the thoracic viscera, I was ex-
ceedingly surprised to see the naked heart
lying on the left side of the chest, and could
scarcely at first believe what I saw, but the
circumstances were too strong to keep me long
in doubt. The heart was as bare and distinct
as it commonly appears in opening into the
cavity of the pericardium, and every collateral

circumstance confirmed the fact The

heart lay loose in the left cavity of the chest,
unconnected in any way except by its vessels ;
was of a large size, elongated in its shape,
and had its apex opposite to the eighth rib.
The right auricle was obviously in view in the
same manner as when the pericardium has
been opened, and the vena cava superior and
inferior were clearly observed entering into it.
The appendage of the left auricle was as clearly
in view; and when the heart was inverted, so
as to have its apex turned upwards, the extent
of its cavity was seen with the two pulmonary

* On the want of a pericardium in the human body,
in Transactions of a Society for the Improvement
of Med. and Chir. Knowledge, vol. i. p. 91, with
a plate of the appearances.

634

ABNORMAL CONDITIONS OF THE HEART.

veins of the left side entering behind the ap-
pendage. The right and left ventricles were
distinct, with the coronary vessels running
upon them ; and the aorta and pulmonary
artery were seen clearly emerging from them."
There is nothing in Dr. Baillie's description
to indicate positively whether the visceral layer
of the serous pericardium was absent or not,
although we may infer its absence ; what he
says bearing upon this subject is as follows :
" The heart was involved in the reflection of
the pleura, belonging to the left side of the
chest, which became its immediate covering,
and upon making the slightest incision into the
substance of the heart, its muscular structure
was laid bare, as in any common heart de-
prived of its pericardium."

Breschet* has put on record a case in which
the pericardium was absent, not altogether, but
in greatest part. The subject of it was a
young man of twenty-eight years of age, who
died in the Hotel Dieu of an inflammatory
affection of the intestines. The heart lay free
under the left lung without any external fibro-
serous envelope. The mediastinum was
formed only by a simple serous lamina belong-
ing to the right pleura, and upon the left of
this lay a rudimentary fibrous capsule, attached
above to the origin of the great vessels. The
serous membrane was altogether absent, but
the heart was immediately inverted by a serous
lamella, which was prolonged from the left
pleura. In both this case and that of Baillie,
the left phrenic nerve was displaced and brought
towards the mesial line of the body, and not
covered by the serous membrane, — an anato-
mical character, which, as Breschet suggests,
may serve to distinguish congenital absence of
the pericardium from the simple adhesion of
that membrane to the heart.f

II. Malformations of the heart by excess of
developement. — Plurality of the heart itself
may be obviously regarded as coming under
this head ; but I am not aware of any instance
in which a double heart has been found in a
perfect single foetus, nor can the possibility of
such an occurrence be deemed admissible.
It is in monsters formed by the junction of two
that this double form of the heart has been met
with. Thus, in one case referred to in Bouil-
laud's work, all the upper parts of the foetus
were double, while the inferior were simple.
There were two heads, two necks, quite separate
and of the ordinary size. The necks terminated
in a single very wide thorax, to the upper part
of which and between the insertion of the
two necks an arm was attached in the vertical
direction, one perfectly formed arm being
placed on each side of the thorax. There were
four lungs, each having a distinct pleura, but
only one diaphragm : there were also two
hearts and two pericardia, each of which had
two venae cavae and a pulmonary artery, four
pulmonary veins and an aorta. The two aortae

* Mem. sur un vice de conformation congenitale
des enveloppes du cceur : Rep, Gen. d'Anat. t. i.
p. 212.

t See references to other cases in Otto's Path.
Anat. by South, p. 254.

united at the lower part of the dorsal region
of the spine, and formed the artery by which
the abdominal viscera and lower extremities
were supplied.

The evidence respecting the occurrence of
an increase in the number of the parts of the
heart is very unsatisfactory. The often quoted
case of Kerkring,* with a double right ven-
tricle; one by Vetter,f with four auricles and
four ventricles, quoted by Otto ; a third by Che-
mineau,J with three ventricles, are, if genuine,
the most remarkable instances on record, be-
sides various instances in the lower animals,
especially birds. Andral states that he has
seen a heart with three auricles, and another
with four ventricles : it is much to be regretted
that he has given no description of these sin-
gular malformations §

Supernumerary cavities, or septa dividing
the primitive cavities of the heart, are the most
common instances of excessive developement.
Adopting the arrangement of Andral,|| we
find — 1, a supernumerary cavity forming a
sort of accidental appendage to one of the
auricles or ventricles, and communicating with
the cavity of the part to which it is attached :

2, a supernumerary septum, forming an im-
perfect division of one of the natural cavities ;

3, a second cavity, completely partitioned off
by one of these septa, and giving off super-
numerary vessels, which communicate with the
regular vessels of the heart. It appears to me,
however, to be very questionable that all cases
of supernumerary cavities are the result of ex-
cessive development, but that, on the contrary,
they are sometimes mechanically consequent
upon defective formation in other parts. At
least it is in this way that I account for the con-
dition of the heart of a boy, aged ten years,
which I examined several years ago, and which
has been described by my respected friend, Dr.
John Crampton, in the Transactions of the
Dublin College of Physicians for 1830. In
this heart there were three instances of defective
developement — absence of the valves of the
pulmonary artery, an open foramen, and an
imperfect septum ventriculorum. Attached to
the right ventricle there was a supernumerary
cavity with which the pulmonary artery com-
municated. This cavity communicated also
with the right ventricle, by an opening large
enough to admit the little ringer, and formed
under the columns carnese of the ventricle. The
pulmonary artery was not only destitute of
valves, but at the usual situation of the valves
its lining membrane was puckered, by which
its orifice was manifestly contracted. The su-
pernumerary cavity, in this instance, was in all
probability occasioned by a partial dilatation
of the infundibular portion of the right ventri-
cle, in consequence of the obstruction at the
pulmonary orifice.

Increase in the number of the valves of the
large arteries may be counted among the ab-

* Spicil Anat. obs. 69, p. 139.

t Aphorism, aus der Pathol. Anat.

J Hist, de 1'Acad. des Sc. an. 1699.

$ Path. Anat. by Townsend, vol. ii. p. 333.

II Loc. cit.j

ABNORMAL CONDITIONS OF THE HEART.

635

normal formations by excess. Thus, four or
even five valves are occasionally found in the
pulmonary artery more frequently than in the
aorta. The supernumerary valves are always
small, and sometimes appear to have been
formed at the expense of the next normal one.
Anomalous connexion of the vessels oj' the
heart. — Our space will only permit us to
enumerate the principal observed varieties.
1. The aorta or pulmonary artery, or both,
appear to arise equally from both ventricles,
the septum of the ventricles being more or less
deficient. 2. The aorta may arise from the
right ventricle, and the pulmonary artery from
the left, the veins preserving their natural posi-
tion. 3. The vena azygos opens into the
right auricle. 4. The hepatic veins open into
the right auricle. 5. The ductus arteriosus
opens into the right ventricle. 6. Two superior
venae cavse open into the right auricle. 7.
Very rarely the right auricle gives insertion
to one or more pulmonary veins, and on the
other hand the left auricle receives sometimes
the superior vena cava, and at other times the
inferior. 8. Meckel states that he has seen the
great coronary vein of the heart to open into
the left ventricle.* Professor Jeffray, of Glas-
gow, relates a case in which the inferior cava
opened into the upper part of the right auricle,
taking the course as well as the place of the
vena azygos.

On displacement or ectopia of the heart as a
consequence of* disease. — The most common
cause of morbid displacement of the heart is
an effusion of air or liquid into one of the
pleural cavities. The displacement is most
manifest when it follows effusion into the left
side, by which the heart is pushed over to the
right, the degree of displacement depending
on the amount of effusion, and thus alteration
of the heart's position becomes one of the
diagnostics of empyema, hydrothorax, pneumo-
thorax. In general, the more rapid the effusion
the more certainly will the displacement be
effected, and the greater will be its extent. In
nine cases out of ten, as my friend Dr. Towns-
end remarks,f when the heart is removed out of
its natural situation, the displacement will be
found to have arisen from empyema or pneumo-
thorax ; and of twenty-seven cases observed by
him, the heart was perceptibly displaced in
every instance. On the other hand, when the
effusion is slow and gradual, the extensibility
of the neighbouring textures is more completely
brought into play, and the displacement of the
heart is thus counteracted, whence it happens
that in cases of chronic dropsical effusions into
the chest, displacement of the heart is not of
frequent occurrence, nor is it extensive when it
does take place. When the effusion occurs on
the right side, the heart may be pushed more to
the left, and upwards, than is natural, but to
effect this a considerable effusion is necessary.
The first notice of this fact is due to my able
friend, Dr. Townsend, to whose article I have
already referred. In a case of pneumothorax

* This enumeration is taken from Bouillaud,
Traite des Maladies du Coeur, t. ii. p. 588.
t Cyclop. Pract. Med. vol. ii. p. 390.

to which he refers, and which I also witnessed,
the effusion was on the right side, and the
heart was distinctly seen and felt pulsating
between the fourth and fifth ribs, near the left
axilla. After paracentesis, which was performed
by the late Dr. M'Dowel, the heart gradually
returned to its normal position, as the displacing
force was removed by drawing off the air and
fluid contained in the opposite pleura. More-
over, as has recently been ascertained by Dr.
Stokes, the absorption of an effusion of the right
side will cause the heart to be displaced to that
side, the pleural cavity being obliterated by
lymph, while the lung of the left side is en-
larged so as to aid in occupying the vacant
space and pushing the heart over.

It is scarcely necessary to observe that tu-
mours forming in the right or left sac of the
pleura may occasion displacement ; thus aneu-
rismal tumours may push the heart to the right,
to the left and upwards, or even forwards and
outwards against the wall of the thorax, or
downwards, so that its apex will pulsate in the
epigastrium. Of this last displacement, Dr.
Townsend* relates an example. I have my-
self observed, some years ago, a case where the
heart was pushed forwards and outwards, and
as it were compressed against the ribs by an
enormous aneurism of the thoracic aorta; the
sounds of the heart were so modified by this
compression as to lead to the erroneous diagnosis
of concentric hypertrophy. In the case recorded
by Drs. Graves and Stokes,f the heart was
pushed upwards and to the right side by an
abdominal aneurism, so as to pulsate in the in-
tercostal space of the third and fourth ribs. Dr.
Hope mentions the displacement to the left by
an aneurism of the ascending aorta. Any
cause which pushes the diaphragm upwards
and prevents its descent, such as distension of
the abdomen by an enlarged viscus, a tumour,
or an effusion, will change the position of the
heart, so that its axis will be directed horizon-
tally ; and Dr. Hope has remarked that the
same position may be produced by an adhesion
of the pericardium to the heart, by which its
enlargement downwards is prevented. A
diaphragmatic hernia will displace the heart to
an extent proportionate to that of the visceral
protrusion. In a case recorded by Drs. Graves
and Stokes, the stomach and a large portion of
the transverse arch of the colon were lodged in
the left cavity of the thorax, and pushed
the heart and mediastinum towards the right
side. When the lung is enlarged from dilated
air-cells, the heart may be displaced : it may
be drawn considerably downwards by the dia-
phragm, which yields before the enlarged lung,
thus increasing the vertical diameter of the
chest ; or it may suffer a slight degree of lateral
displacement, the mediastinum being pushed to
the right side by the lung.J

Dr. Stokes has related the remarkable, and
so far as I know unique case of displacement,
or as he terms it " dislocation," of the heart

* Loc. cit.

t Dub. Hosp. Rep. vol. v. p. 10.
j See Dr. Stokes's valuable work on Diseases of
the Chest, pp. 187-191.

ABNORMAL CONDITIONS OF THE HEART.

636

from external violence. The patient was
crushed between a water-wheel and the em-
bankment on which the axle was supported.
Several ribs were broken, as well as the right
clavicle and humerus. The heart, which, ac-
cording to the statement of the patient, had
always occupied its natural situation, was now
found beating at the right side.*

MORBID ALTERATIONS OF THE MUSCULAR
SUBSTANCE OF THE HEART.

1 . Inflammation of the muscular structure of
the heart, or carditis (the carditis proper of some
pathologists). — The same anatomical characters
which would lead us to pronounce any muscu-
lar tissue in a state of acute inflammation,
would justify a similar conclusion respecting the
heart. But from the sparing deposition of cel-
lular tissue around this organ and between its
fibres, the anatomical phenomena which denote
the previous existence of inflammation are not so
marked in it as in the muscles of animal life ; and
judging from the rarity of these organic signs, as
well as from the unfrequent occurrence of those
symptoms which so great a morbid process could
scarcely fail to produce, we may reasonably
conclude that active inflammation deeply im-
plicating the carneous fibres of the heart, and
originating in them, is very seldom met with.

The anatomical characters indicative of car-
ditis are a dark, almost black, colour of the
muscular substance, the fibres of which have
lost in a great measure their cohesive power;
they are very compressible and readily torn,
and consequently cannot be easily isolated to
any great extent, although easily separable en
masse. When the muscular wall of either ven-
tricle is pressed, the blood oozes out from the
divided vessels on the cut surface in much
greater quantity than usual. In Mr. Stanley's
case, as in all cases, the dark colour of the
fibres " evidently depended on the nutrient
vessels being loaded with venous blood." When
in addition to these signs we find purulent de-
posits in various parts of the muscular struc-
ture, and moreover, when it is manifest that the
internal and external membranes are implica-
ted, from the effusion of coagulable lymph on
them to a greater or less extent, no doubt can
be entertained respecting the exact nature of
the lesion. In Mr. Stanley's case, " upon
looking to the cut surface exposed in the section
of either ventricle, numerous small collections
of dark-coloured pus were visible in distinct
situations among the muscular fasciculi."f A
similar case has been recorded by Dr. P. M.
Latham, the anatomical characters of which ac-
corded with those above mentioned. " The
whole heart was found deeply tinged with dark-
coloured blood, and its substance softened ; and
here and there, upon the section of both ven-
tricles, innumerable small points of pus oozed
from among the muscular fibres." J

Every anatomist must have noticed how
variable is the colour and the consistence of the
muscular structure of the heart, even indepen-

* Med. Gazette, vol. viii.
t Med. Chir. Trans, vol. vii.
t Med. Gazette, vol. iii.

dent of disease of the lining tissues. The pale,
soft, compressible, flexible, and, to use a com-
mon word, flabby heart, strongly contrasts wit^i
the firm, plump, fresh-looking elastic one ; in
the former, the flaccid parietes fall together im-
mediately the cavities are emptied ; in the lat-
ter, the surfaces retain their convexity, although
the contents of the cavities have been com-
pletely removed. Between these two extremes
there are various grades of colour and consis-
tence, of which Bouillaud particularises three
as being the result of inflammation, the red
softening , the white or grey, and the yellow.
The first is probably that which may be said
unequivocally to follow primary inflammation
of the muscular texture ; the other two, how-
ever, as Bouillaud admits, occur most fre-
quently in connection with pericarditis : they
occur, too, as Dr. Copland observes, where no
sign of inflammation is manifest, and where
during life there had been no evidence of car-
diac disease ; in cases of general cachexia and
of constitutional disease, attended by discolora-
tion of the surface of the body, arising, in fact,
as Dr. Williams explains, from an altered state
of the nutrition of the organ, owing perhaps to
partial obstructions in the coronary vessels ra-
ther than to the immediate influence of inflam-
mation. This last excellent observer makes the
following judicious remarks in reference to this
matter.* " To judge that the tissue of the
heart is especially diseased, we must see that it
differs much in appearance from the other
muscles of the same subject. You will find,
on comparing the same muscles in different
subjects, a remarkable variety of colour; and
in some there is no freshness in any of the
muscles, but all are pale, and verging on a
pinkish drab or dingy brick colour." Perhaps
the most correct arrangement of the various cir-
cumstances under which softening of the heart
may take place is that given by Andral. 1st,
Softening connected with active hypersemia of
the heart ; 2d, softening connected with anaemia
of the heart; 3d, softening connected with
atrophy of the heart; 4th, softening connected
with an acute alteration in the general nutritive
process (as in typhus); 5th, softening connected
with a chronic alteration in the general nutritive
process (as in a variety of chronic diseases) ;
6th, softening which we are not yet enabled to
refer to any morbid condition of the heart itself
or of the rest of the system.f

Suppuration.— 'The occurrence of an abscess
uncomplicated with any other lesion in the
walls of the heart, does not unequivocally de-
note the previous existence of carditis, although
it may afford strong presumptive evidence of
the fact : when, however, we find abscess, with
lymph or adhesions of recent date, we may rea-
sonably infer its inflammatory nature. Dr.
Copland has introduced in a note to his inva-
luable and profoundly learned article on Dis-

* Lectures on Diseases of the Chest, Med. Gaz.
vol. xvi.

t Otto says that violent exertion appears as in
other muscles to render the heart easily broken
down ; thus, for instance, it is found very weak in
hunted deer.

ABNORMAL CONDITIONS OF THE HEART,

637

eases of the Heart,* an abstract of several cases
in which pus was found in the substance of the
heart. Those quoted from Corvisart, Raikem,
and Simonet, and probably that from Dr.
Graves,t may be regarded as examples of puru-
lent formation following carditis, general or
partial. So likewise is Laennec's case, in
•which, however, the carditis was consequent
upon pericarditis. There is no anatomical cha-
racter which will enable us to distinguish whe-
ther a simple purulent deposit, surrounded by
natural muscular texture, be inflammatory or
not, for there is no reason why the heart should
be exempt from that which we know often
occurs in other muscles, namely, non-inflam-
matory deposits.

Ulceration. — As true carditis seems to be
generally admitted to be rare, so we may con-
clude that ulceration is equally so. It is by
the ulcerative process that some of the perfora-
tions or ruptures of the parietes of the heart
take place ; it is probable, however, that the
great majority of the ulcerations we meet
with commence from the surface, and result
from membranous inflammation rather than
from that of the muscular substance ; the ulcer
commences on the surfaces, either in or imme-
diately subjacent to the internal or external
membrane ; and as it burrows deeply, it may
perforate the muscular wall, and so destroy the
membrane on the side opposite to that on which
the ulceration had commenced. Sometimes an
ulceration of this kind gives rise to aneurismal
tumours or sacs, very variable in size, projecting
from that part of the cavity which corresponds
to the artery. It seems evident that these
tumours are produced by the pressure of the
contained blood distending the thinned and
yielding wall of the heart. We shall return to
this subject further on in treating of aneurisms
of the heart.

Induration. — This condition of the muscular
structure of the heart seems most probably to
be a result of inflammation, especially of the
chronic kind. It is generally found in small
circumscribed portions ; it may occur in any
part of the heart, and may even co-exist with
softening : the hardened portion has become
particularly firm, is cut with difficulty, and when
struck with the scalpel sounds, as Laennec
says, like a leather dice-box. It is harder,
denser, less elastic, and as regards colour is
paler than the hypertrophied muscular tissue.

Cartilaginous and osseous transformations. —
Induration of the subserous cellular tissue of
the heart is in general the precursor of many of
these transformations. This indurated portion
increasing in thickness gradually assumes the
appearance of cartilage — in this cartilage the
calcareous particles are deposited. I have not
been able to ascertain whether this so-called
ossification exhibits, on examination by the mi-
croscope, the lamellar arrangement of true bone,
as osseous transformations of certain permanent
cartilages do, those of the thyroid cartilage for
example. These calcareous or osseous patches

* Diet, of Medicine, part iv. p. 191.

t Loud. Med. and Surg. Journal, vol. vii.

or tumours compress the subjacent muscular
tissue, and produce atrophy of them, and ac-
cording to Andral, sometimes are connected by
prolongations of the same material with other
calcareous deposits formed round the orifices.
Many pathologists believe that these transfor-
mations are the result of inflammation. I sup-
pose there can be no doubt that they follow an
increased afflux of blood, and so they may be
considered, although not an immediate, at least
a remote effect of inflammation, or rather of the
altered nutrition and secretion to which inflam-
mation gave rise.

In a case recorded by my friend Mr. Robert
Smith, of Dublin, the apex of the left ventricle
was converted into a dense, white, firm, car-
tilaginous structure, the division of which with
a scissors required the employment of con-
siderable force ; the alteration of structure had
extended to some of the carneae columnae.*

Tubercles. — These productions are very
rarely if ever met with in the heart. No re-
liance can be placed on most of the instances
recorded, in consequence of the imperfect and
unsatisfactory descriptions accompanying them;
what appears to one person to be tubercular
may present a totally different aspect to another.
Laennec says vaguely, " only three or four
times have I met with tubercles in the muscular
substance of the heart." And Andral states,
that they are never met with in the heart,
except when they likewise occur in other
muscles. Otto says, "although I have dis-
sected a great number of scrofulous men and
animals, I have never found a tubercle on the
heart, and therefore consider them very rare."
Dr. Elliotsonf mentions a case in which there
were scrofulous deposits in the walls of the
left ventricle, surrounded by white and almost
cartilaginous induration. In a case which came
under my own observation, in a woman be-
tween 50 and 60 years of age, there were several
white tumours in the parietes of the right
ventricle, each about a quarter of an inch in
diameter, of uniform consistence throughout,
nor showing any disposition to softening in the
centre.

Scirrhus. — Equally unsatisfactory are the
reports of anatomists respecting this alteration.
Rullierand Billard relate cases in which scirrhus
had developed itself on the heart. Rullier'sJ
case was an instance of degeneration of the
whole substance of the heart into a scirrhous
mass, which formed irregular knobs on the ex-
ternal and internal surfaces of the heart. Bil-
lard found three scirrhous tumours embedded in
the heart of an infant only three days old.§

Medullary fungus, or encephaloid tumours. —
Of these, several instances are quoted by Andral
from others, and he describes two which he
saw himself.|| In the first of Andral's cases the
whole of the walls of the right auricle and
ventricle were converted into a hard, dirty
white substance, traversed by a number of

* Dub. Journal, vol. ix. p. 418.
f Lumleyan Lectures, p. 32.
$ Bull, de la Faculte, 1813.
\ Malad. des Enfans.
f| Loc. cit. vol. ii. p. 346.

638

ABNORMAL CONDITIONS OF THE HEART.

reddish lines, and possessing all the characters
of encephaloid. In the second case, the
external wall of the right ventricle was occu-
pied by a tumour extending from its apex to
its base, which projected so far externally as to
lead him to mistake it for a supernumerary
heart, and likewise protruded internally into
the cavity of the ventricle. In a case which I saw
myself, the tumour resembled the well-known
encephaloid or cancerous tumour of the liver,
being, like it, raised above the surrounding
muscular structure, and irregular on its surface.

Mclanosis. — This deposit is also found very
distinctly in the heart. It appears in the form
of small spots under the pericardium or endo-
cardium, or as tumours in the substance of the
ventricle. In a specimen in the Museum of
King's College, London, the melanotic deposits
are situated, some beneath the pericardium
covering the right ventricle, and others on the
carneae columns of the same cavity,immediately
subjacent to the endocardium. Neither Andral
nor Bouillaud notices the occurrence of me-
lanosis in the heart.

Hypertrophy of the heart. — When the walls
of any of the heart's cavities experience an in-
crease of thickness, owing to the developernent
of the muscular substance, they are said to be
in a state of hypertrophy; and there is no
morbid state of this organ which is more fre-
quently brought under the notice of the phy-
sician than this, as affecting the parietes of one
or more of its cavities. There is no alteration
in the muscular texture apparent to the naked
eye, except, perhaps, a slight increase of the
red colour — the heart is firm, dense, and
elastic ; in short, it presents all those characters
which we so often see manifested in the ex-
ternal voluntary muscles, the developernent of
which is increased by frequent use.* Hyper-
trophy may affect all the cavities simultaneously,
but in general it is limited to one or at most
two cavities. The left ventricle is that in which
it most frequently occurs, next the right, and
lastly and rarely the auricles. Nor does the
hypertrophy affect necessarily the whole pa-
rietes of the cavity, but sometimes it is
limited to a small portion, or to the septum,
or to one or more of the carnese columnae. In
some cases, as Andral remarks, the thickening
may be at its maximum at the base of the
heart, and diminish gradually towards its apex,
which sometimes retains its natural thinness,
when all the rest of the parietes are three or
even four times as thick as natural ; or at other
times, as Cruveilhier observes, becomes so thin
that one is astonished that perforation or dila-
tation of the heart at its apex is not more com-

* Dr. Williams mentions that in leucophlegmatic
subjects the muscular texture is soft and flabby
and of a duller colour. This is obviously a con-
dition resulting from other causes, and not a cha-
racter of the hypertrophous heart as such. And
the threads or laminae of dirty white tissue inter-
mingled with ihe muscular tissue, described by
him, seem clearly the result of the inflammation
which caused the concomitant adhesion of the peri-
cardium. In the same light I would regard the
dense fibrous tissue described and delineated by
Carswell.— See Med. Gax. vol. xvi. p. 915. _,

mon. In other individuals again the thickening
is equal and uniform from the base to the apex,
which then loses its pointed form and acquires a
rounded shape. Lastly, it sometimes happens
that the hypertrophy is greatest about midway
between the apex and base of the heart, or is
even exclusively confined to that part. When
the septum is principally affected, the capacity
of the right ventricle is so diminished that it
sometimes looks like a small appendix attached
to the left ventricle.* When the hypertrophy
affects chiefly or exclusively the right ventricle,
the apex of the heart seems to be formed by it,
whereas in the normal state the apex belongs
to the left ventricle.

An hypertrophous state of the parietes of
all the cavities not only affects the form of the
heart by changing it from the oblong to the
spherical, but, as was first noticed by Dr.
Hope,t its position is altered ; <l as the dia-
phragm does not retire sufficiently to yield
space downwards for the enlarged organ, it
assumes an unnaturally horizontal position,
encroaching so far upon the left cavity of the
chest as sometimes to force the lung upwards
as high as the level of the fourth rib or even
higher."

Berlin]; distinguishes three varieties of hy-
pertrophy of the heart. 1. That in which the
hypertrophy is not accompanied with any alte-
ration in the capacity of the cavities of the
heart — simple hypertrophy. 2. That in which
there is dilatation of the cavity along with
the increased substance of its walls — excentric
hypertrophy or active aneurism of Corvisart.
3. Where the capacity of the ventricle is dimi-
nished as if the walls had encroached by their
increase of thickness upon the cavity, or as
Bouillaud expresses it, as if the internal mus-
cular layers and the carneae columnae were prin-
cipally the seat of hypertrophy — concentric hy-
pertrophy.§ Of these the most frequent is that
which is accompanied by dilatation, the dilata-

* Cruveilhier doubts the occurrence of partial
hypertrophy affecting the septum or one or more
carneae columnae.

t Cyclop, of Pract. Med. art. Hypertrophy of
the Heart.

I Maladies du Cceur.

§ A certain standard of health, is absolutely
necessary to enable us to determine as to the ex-
istence of disease. With this view we transcribe
here the table of weight and dimensions drawn up
by Bouillaud as the average of health.

In an adult of ordinary size and good constitu-
tion the mean weight = 8 to 9 oz. ; mean circumfe-
rence =8 to 9 inches; mean of the longitudinal
and transverse diameters = 3i inches (the latter
generally predominates slightly over the former) ;
the mean of the antero-posterior diameter =2 inches.
Mean thickness of the walls of left ventricle at the

base= . . . . 6 to 7 lines.

Ditto, right ventricle at the base = . 2i lines.
Ditto, left auricle = . . . U lines.

Ditto, right auricle=. . . 1 line.

The average capacity of the ventricles is suffi-
cient to contain a hen's egg ( that of the right ven-
tricle slightly exceeding the left).

For some useful observations on this subject, and
on the normal weight, bulk, &c. of the heart in
relation toother viscera, see Dr. Clendinning's Lec-
tures iu Med. Gazette, vol. xvi.

ABNORMAL CONDITIONS OF THE HEART.

639

lion in all probability preceding and giving rise
to the hypertrophy by rendering an increased
force of contraction necessary. Simple hyper-
trophy is the least common, according to
Bouillaud ; concentric hypertrophy, according
to this physician, is not rare. Considerable
doubt, however, has been excited recently by
the high authority of M. Cruveilhier as to the
real existence during life of such a condition
as this. This anatomist believes the diminished
cavity to be merely the result of a tonic con-
traction of the muscular \vall of the ventricle
in death. " The concentrically hypertrophied
hearts of Berlin and Bouillaud appear to me,"
he says, " to be hearts more or less hypertro-
phied, which death surprised in all their energy
of contractility."* The hearts of all those
examined by Cruveilhier, who died by the
executioner, presented to his observation to a
great degree the double phenomenon of in-
creased thickness of walls and diminished
cavity, and he has observed the same with per-
sons who died a violent death.f On one occa-
sion I was particularly struck with a similar
condition of the heart of a donkey which had
been accidentally transfixed by a large trocar,
whereby the death of the animal was caused in
a few minutes. The muscular structure of the
heart was singularly dense. It had contracted
at its apex quite to a sharp point, and on cut-
ting into it the cavity of the left ventricle ap-
peared almost obliterated, and the muscular
wall much increased in thickness. I have
many times, too, observed the fact noticed by
Cruveilhier, that the cavity may be easily en-
larged or restored to its natural dimensions by
introducing the finger and dilating it, or still
more easily, if the heart have been macerated
in water for a short time previously. This fact
is further confirmed by Dr. Budd, who sup-
ports the views of Cruveilhier in an interesting
paper in the last volume of the Medico-Chirur-
gical Transactions. In one of Dr. Budd's cases
the thickness of the parietes of the left ventricle
eighteen hours after death varied from an inch
to an inch and a half, on a transverse section
made at a distance from the apex of one-third
of its length, and the cavity was not large
enough to hold the second phalanx of the
thumb, and was almost filled by the carneae
columnae. This heart, in its open state, was
put to macerate ; no force was applied to extend
it. At the end of some days, on being folded
up, it was found to have dilated very conside-
rably, so that the left ventricle could not then
be said to be smaller than natural. Dr. Budd
argues against the existence of the diminished
cavity from the fact that of eight cases collected
by him, no one afforded signs, either during
life or after death, of any obstacle to the circu-
lation through the heart. There were no irre-
gularity of pulse, no dropsy during life, no di-
latation of the right cavities after death, pheno-
mena which, it may be said, must of necessity
be present if there be an obstacle to the circu-

* Diet, de Med. et Chir. Prat. art. Hypertrophie.
f Mr. Jackson and Dr. Budd have observed this
state of the heart in persons who died of cholera.

lation in the heart. It is impossible, as he
states, to conceive that a left ventricle, which
could scarcely hold an almond, should offer no
obstacle to the circulation through the heart.
Yet Laennec has recorded a case in which the
parietes of the left ventricle had acquired the
thickness of from an inch to an inch and a half,
and the cavity seemed capable at most of con-
taining an almond stripped of its shell. Yet
the day before the patient's death his pulse was
natural, the breathing perfectly free, " and
nothing," says Laennec, " led me to suppose
that this man had a disease of his heart."

Hypertrophy with dilatation. — It is in this
morbid condition that the heart acquires the
greatest increase of size as well as the most
striking alteration of form. The cor bovinum
of some authors, so called from its enormous
size, affords an instance of an extreme develope-
ment of this form of disease. The extent to
which the heart may become enlarged in this
way is quite extraordinary. Of certain cases
recorded by Bouillaud, in one the right ventri-
cle was large enough to contain a goose's egg,
and the left, still larger, the closed hand of a
female; in another, the left ventricle was simi-
larly increased in capacity. In a third, the
right auricle of a child, aged seven years, was
so dilated as to contain a coagulum as large as
the closed hand of an adult. The thickness of
the left ventricle in Bouillaud's cases varied
from 7 to 14 lines, that of the right 3 to 5 lines;
but in some instances it was as considerable as
from 8 to 10 lines or 11 to 16 lines. The weight
of the heart, in some instances, trebled the na-
tural ; thus in one case of general hypertrophy
the weight was 22 ounces, and others weighed
from 13 to 20 ounces. The circumference of
the heart was often increased to twelve inches,
the longitudinal diameter five inches, and the
transverse eight inches. In a patient who died
at the Hotel Dieu in 1834, the heart measured
fifteen inches and a half at its base. Hypertro-
phy seldom occurs in the auricles, except when
accompanied by dilatation : the musculi pecti-
nati are generally the seat of the increased mus-
cular developement, and as the number and
developement of these muscular columns is
greater in the right auricle than in the left in
the normal state, (in the left they are only found
in the auricular appendage,) the remark of Dr.
Hope follows almost as a matter of course,
namely, that in the right auricle hypertrophy
proceeds to the greatest extent, its walls being
sometimes rendered nearly equal in thickness
to those of the right ventricle in the normal
state.

In the vast majority of cases of this kind the
products of inflammatory states of the pericar-
dium or endocardium, or its appendages, are
present; in short, a diseased state of the valves
constantly co-exists with hypertrophy and dila-
tation. These conditions of the cavities are very
frequently traceable to some obstacle to the cir-
culation through the heart, and sometimes it
would seem that the valvular disease preceded
and gave rise to the hypertrophous and dilated
cavity; but it is not impossible nor unlikely
that the valvular disease may follow the hyper-

640

ABNORMAL CONDITIONS OF THE HEART.

trophy, and may result from the violence of
contraction of the enlarged ventricle. Dilata-
tion of the aorta at its commencement and its
arch is frequently the consequence of this dis-
ease in the left ventricle, and dilatation of the
pulmonary artery ensues upon it in the right
ventricle.

Dilatation of the cavities of the heart. —
" V\ hen the heart is incapable of sufficiently
expelling its contents, whether in consequence
of obstruction in the vessels from it, of regurgi-
tation into it through imperfect valves, of want
of power, of irritability, or of both, it becomes
distended, and in time permanently dilated."*
We have already described that kind of dilata-
tion which is the most common, namely, that
accompanied by hypertrophy ; dilatation also
occurs in connexion with an opposite condition
of the parietes, namely, attenuation of them.
The muscular tissue has lost its tone, and
yields, as it were, without resistance to the dis-
tending force. It is laid down by authors that a
third variety of dilatation may exist, what they

spot so often seen upon the external surface of
the right ventricle is an almost invariable at-
tendant upon the dilated heart. Dilatation,
may affect any or all of the heart's cavities ; but
it is met with by far the most frequently in the
right ventricle, and very commonly both ven-
tricles are dilated, in which case the right cavity
is generally more capacious than the left.

An extreme case of dilatation is afforded in
an example quoted by Bouillaud : " the right
cavities were so dilated and their walls so at-
tenuated, that the auricle was converted into a
kind of transparent membrane, and the ventricle
was reduced only to the ordinary thickness of
the auricle."

In determining as to the degree of attenua-
tion of the walls which may accompany any
particular case of dilatation of the auricles, the
anatomist must bear in mind that even in the
natural state the interval between the musculi
pectinati of the right auricle is only composed
of the endocardium and pericardium, separated
by a very fine and transparent cellular tissue,

call simple dilatation, or that in which, while and by a few muscular fibres crossing obliquely
the cavity is dilated, the parietes are of their na- from one pectinate muscle to the next one. I

tural si2e. It seems to me impossible that any
cavity of the heart can, in a dilated state, conti-
nue of the natural thickness without hypertrophy,
in the absence of which dilatation implies neces-
sarily a diminution in thickness; during dia-
stole the parietes of the heart's cavities are thin-
ner than during systole ; what a contracted
muscle gains in one dimension it loses in ano-
ther ; and the same may be said of a relaxed or
distended muscle. Again, if we contrast a con-
tracted with a dilated bladder, it seems evident
that we cannot innate the former, however in-
completely, without producing a manifest dimi-
nution in the thickness of its walls. Hence I
infer, that if the parietes of any cavity be per-
fectly natural, they must become thinned under
the influence of the force which produces the
dilatation; and, on the other hand, if we find
that the parietes of a dilated cavity possess the
normal thickness, we may be assured that it is
slightly hypertrophous. It appears then to be
most correct to limit the varieties of dilatation
to two, that with hypertrophy and that with
attenuation, or the passive aneurism of Corvisart.
In this latter form of dilatation, then, we see
a manifest alteration of the muscular tissue; it
is paler, softer, less resisting, less elastic than
natural. When the heart is emptied of its con-
tents, the walls do not at all return upon them-
selves, but remain flaccid ; nor when cut do
they show any disposition to retract ; and it is
this state of the muscular substance which will
serve best to enable the anatomist to distinguish
morbid dilatations from those which result from
mechanical distension of the cavity by a coagu-
lum formed at the time of death. An obvi-
ously diseased state of both the internal and
external membranous coverings of the heart is
constantly present along with this form of dila-
tation. These membranes lose their transpa-
rency in several parts, apparently from some
abnormal deposit subjacent to them : the white

» Dr. Williams, loc. cit.

have twice seen a perfectly natural right auricle
carefully put up as a museum specimen of
morbid attenuation of the parietes, owing to
ignorance or forgetfulness of this fact.

Dilatation of' the orifices of the heart. — As a
natural result of dilated cavities we meet with
dilated orifices of the heart, and the enlarge-
ment of which again produces in many cases
insufficiency of the valves. Bouillaud gives
the measurement of the auriculo-ventricular
orifice (which is the most liable to dilatation)
in three hearts ; in one it measured five inches
in circumference, and in another four inches
three lines, while in a third the dilatation was
stated to be so great that the tricuspid valve
could not be closed.

Aneurism of the heart. — A diseased state of
the heart occurs not unfrequently, strongly
analogous to that which under the same name
is so well known as occurring in the arterial
system. Most of the varieties too of arterial
aneurism find their analogues in the heart:
thus we have, 1. the aneurism by simple dila-
tation, or true aneurism, resulting from partial
dilatation of one of the heart's cavities; 2.
the false aneurism or that resulting from rup-
ture of one or more of the textures entering
into the formation of the heart's parietes ; 3.
we find the dissecting aneurism analogous to
that remarkable form of arterial aneurism
first described by the late Mr. Shakelton ; 4.
not improbably, we also meet with what is
analogous to the varicose aneurism, and may
be designated spontaneous varicose aneurism of
the heart. To the zeal and acuteness of Mr.
Thurnam * morbid anatomists are much in-
debted for his having arranged, compared, and
classified a considerable number of cases of
aneurismal dilatations connected with the heart,
either observed by himself, or preserved and

* Vide his valuable monograph on Aneurisms of
the Heart in Med. Chir. Trans, vol. xxi. An ap-
pcndix containing references to cases is added.

ABNORMAL CONDITIONS OF THE HEART.

641

recorded by others, whence lie has been able
distinctly to prove the analogies above-men-
tioned, and by which much light has been
thrown upon those forms of disease. -

The partial dilatation of one of the cavities,
or true aneurism, is by far the most com-
mon of the varieties above-mentioned. In
its early stage this disease consists in little
more than a bulging of the wall of the ventricle
or auricle in a certain direction ; as this in-
creases a pouch or sac is formed, which com-
municates with the heart's cavity by a more or
less narrow opening. In some cases this sac
does not extend beyond the external surface of
the heart, nor would it be detected, were the
anatomist to content himself with merely ex-
amining the exterior, it is as it were lodged in
the fleshy substance of the ventricular paries ;
but in other instances a tumour is formed pro-
jecting considerably beyond the exterior. As in
arterial aneurisms, the sacs frequently contain
laminated coagula, and, as might be expected
(i priori, the larger the cavity and the narrower
its orifice of communication, the more abun-
dant is this lamellar deposit. One or more
aneurismal sacs may belong to the same cavity:
thus, in fifty-two out of fifty-eight cases col-
lected by Mr. Thurnam, only one aneurism
existed in each ; but in four cases two were
met with in each; in one there were three,
and in another four incipient aneurisms. In
two instances, Mr. Thurnam states, it is not
improbable that two sacs which were originally
distinct had coalesced, so as to form a single
aneurism, and in another case three sacs ap-
pear to have united in this way. We find the
aneurismal pouches of all sizes : in nine of the
cases referred to in Mr. Thurnam's memoir,
the size might be compared to that of nuts ;
in twenty, to that of walnuts; in seven, to
fowl's eggs; in fourteen, to oranges ; and in
nine cases, it almost or quite equalled that of
the healthy heart itself. We cannot always
satisfactorily ascertain what textures enter into
the formation of these sacs; however, in the
majority of cases, the three structures of which
the heart's parietes are composed are found in
the walls of these sacs ; in others the muscular
tissue has disappeared, atrophied probably by
the pressure, and the wall is composed only
of the endocardium and pericardium, and in
others again the endocardium is wanting, and
the muscular fibres and the pericardium are
the only component elements.* In some cases
the wall of the sac is strengthened by an ad-
hesion formed with the loose layer of the peri-
cardium.

These aneurisms are always in connection
with the left ventricle or left auricle; very rarely
however with the latter, and never with the
right cavities. In the paper already quoted
from, Mr. Thuruam has collected references to
fifty-eight cases of aneurism of the left ven-
tricle, and eleven of the left auricle. All parts
of the ventricle are liable to aneurismal dila-
tation, but it occurs most frequently at the
apex: next in frequency it is found at dif-

ferent points of the base; less frequently still
it occurs in the lateral walls at situations in-
termediate to the two last-named, and very
rarely it is met with in the interventricular
septum.

I will give the description of auricular aneu-
rism in Mr. Thurnam's words : " The dis-
ease would appear, from the preparations I have
inspected, and the cases which have been re-
corded, to have been nearly uniformly of the
diffused kind, and to have senerally involved
the entire sinus of the auricle. The dilated
walls of the cavity are often thickened and the
seat of fibro-cellular degeneration. The lining
membrane is opaque, rough, and otherwise
diseased, and in some cases even ossified, and is
lined with fibrinous layers, very similar to those
met with in arterial aneurisms. In all these
cases, the lining membrane appears to have
been continued into the interior of the dilated
portion, which consequently merits the name
true aneurism. Occasionally the dilatation is
confined to the auricular appendage, which
becomes extensively distended with lamellated
concretions."*

The false aneurism, or that resulting from
rupture, must be spoken of merely as a pos-
sible and probable occurrence. I know of no
unequivocal example of it ; but inasmuch as
we must admit that partial rupture of the
heart's wall may take place, we cannot deny
the possibility of the production of cardiac
aneurism in a manner similar to that in which
arterial false aneurism is produced.

Dr. Hope describes cases, which Mr. Thur-
nam very aptly compares to " the dissecting
aneurism." In those cases, Dr. Hope says,
" steatomatous degeneration had caused the
formation of a canal from the aorta underneath
one of the sigmoid valves and the internal
membrane of the left ventricle." But Mr.
Thurnam's explanation seems to me much
more likely to be the true one. He supposes
that the aneurisms had been originally formed
in the ventricle, and had subsequently commu-
nicated with the aorta, as a consequence of the
co-existent disease of the valves of that vessel.

The possibility of the formation of an aneu-
rism resembling the varicose aneurism, has been
likewise suggested by Mr. Thurnam, from the
occurrence of aneurismal pouches in the sep-
tum ventriculorum. If such an aneurism were
to burst, it would establish a communication
with the right ventricle, a portion of the ve-
nous system — thus producing " a lesion alto-
gether analogous to that which results from the
wound of an artery and its accompanying vein,
and to which the name of spontaneous varicose
aneurism of the heart is perfectly applicable."

Mr. Thurnam mentions a fourth form of
aneurism which is not without its analogue in
the arterial system, namely, that in which the
aneurismal sac is formed by the endocardium
and pericardium. This may be compared with
a variety of external aneurism in which the
lining membrane of the vessel protrudes through
a rupture in the middle tunic, constituting a

* Vide Thurnam, loc. cit. p. 219.
VOL. II.

* Loc. cit. p. 245.

2 u

(542

ABNORMAL CONDITIONS OF THE HEART.

lesion which has been sometimes designated
" aneurisma herniosum," and sometimes
" internal mixed aneurism." This form of
arterial aneurism has been described by Haller,
Dubois, Dupuytren, and Breschet.

In a large number of these cases of aneu-
rism of the heart, the pericardium has been at
some period or other of the disease more or
less extensively inflamed, and adhesions are
consequently found : the endocardium like-
wise frequently exhibits marks of inflammatory
action, opacities, white spots, &c. and this
sometimes extends to the valves. In some the
muscular substance in the neighbourhood of
the sac is degenerated, and assumes the cellulo-
fibrous form.*

Atrophy of the heart, — The heart, or a por-
tion of it," may be said to be in the state of
atrophy, when its muscular fibres are pale,
soft, easily torn, inelastic, attenuated, so that
the thickness of the parietes is greatly di-
minished, and the pericardium covering the
heart or the atrophied part of it, is shrivelled
and wrinkled. When atrophy affects the whole
heart, that organ becomes much diminished in
size, the capacity of its several cavities being
proportionally diminished ; and in some in-
stances the diminution of the general size ap-
pears to be more at the expense of the dimen-
sions of the cavities than of the thickness of
the walls.

Morbid deposit of jut on the heart (fatty
degeneration of some authors). There is an
alteration met with not uncommonly in the
muscles of animal life, which is very often de-
scribed as the fatty degeneration of muscle,
but which is in truth an atrophy of the mus-
cular tissue, and not at all a transformation into
fat. This condition, which resembles fat only
in its yellow colour, and may be easily
distinguished from it by its fibrous form, has
never, I believe, been met with in the heart ;
a perfect cessation from active contraction must
be essential to its production ; and as such a
state of quiescence cannot occur in the heart
during life, this form of degenerate muscular
tissue is not found in that organ. We do, how-
ever, meet with cases frequently, in which fat
seems to take the place of the muscular fibres
of the heart : in proportion as they appear to
waste away the fat is deposited under the
serous membrane, until the muscular parietes
of the heart are reduced to a very thin lamina,
of a pale colour and easily torn, between which
and the pericardium a thick stratum of fat is
deposited, so that a superficial examination
might lead one to suppose that the walls of the
heart were wholly converted into this tissue.
The ventricles are generally, if not uniformly,
the seat of this deposit, which must be re-
garded as an increase in the deposit which is

* On the subject of aneurisms of the heart, the
reader may consult with benefit Corvisart's clas-
sical work, Adams in Dublin Hosp. Rep. vol. iv.,
JJreschet sur I'Aneurysme Faux consecntif du
Cirur, Rep. Gen. d'Anat. t. iii., Dr. Hope's work,
Elliotson's Lectures on Diseases of the Heart, but
especially the admirable paper of Mr. Thurnam,

found naturally along the course of the coro-
nary arteries. It occurs chiefly in old persons,
and it is difficult to say whether the muscular
atrophy which is always present is a con-
sequence of the fatty deposit, or precedes it.
So enfeebled has the muscular tissue become
that persons labouring under this disease very
commonly die of a rupture, or rather a giving
way, of the wall of one of the ventricles. It
occurs in persons of debilitated habits, who
either are incapable of active exertion or from
circumstances never attempt it, and, what is
remarkable, the subjects of this disease are
frequently very emaciated: thus M. Bizot*
found this condition in fourteen out of twenty-
nine emaciated females. The disease is like-
wise more common in women than in men ;
and sometimes free oil is present in the blood
in inordinate quantity.

Such I believe to be the correct history of
this state of the heart, of which most erroneous
notions have been formed, owing in a great
measure to the name under which the disease
has been so often described. The description
which I venture to offer has been drawn up
from several cases of the disease in various
grades of the deposit, which have come under
my observation, and on comparing this
description with some of the best detailed
cases on record, it seems perfectly to con-
sist with the appearances described in them.
In Mr. Adams' case,f for instance, " the
right ventricle seemed composed of fat, of a
deep yellow colour through most of its sub-
stance. The reticulated lining of the ventricle,
which here and there allowed the fat to appear
between its fibres, alone presented any ap-
pearance of muscular structure. The left ven-
tricle was very thin, and its whole surface was
covered with a layer of fat. Beneath this the
muscular structure was not a line in thickness,
and was soft, easily torn, and like liver." Two
cases, recorded by Mr. R. Smith,| presented
the remarkable concomitant of an oily con-
dition of the blood ; in one " numerous glo-
bules of oil were found floating on the surface
of the blood which escaped from the divided
vessels ;" and in the other " the surface of the
blood was thickly covered with globules of
limpid oil." In this last case the condition
of the heart's substance is described as follows :
" the heart was remarkably soft, pale, and
flaccid, its substance most easily broken, and
its surface covered with a layer of fat a quarter
of an inch in depth ; the parietes of the ven-
tricles were thin." The anatomical condition
of the former case is not so precisely described
as to admit of comparison. The subjects of
both these cases were old women, one aged
ninety, the other seventy ; and the former died
of rupture of the left ventricle.

I am quite unable to account for the follow-
ing description of a case by Dr. Elliotson.
He says, " I once saw the muscular substance
of the heart completely changed, except at the

* Mem. dc la Soc. Med. d'Observation.
t Dublin Hosp. Rep. vol. iv. p. 396.
$ Dublin Journal, vol. ix. p. 412.

ABNORMAL CONDITIONS OF THE HEART.

648

surface, to fat. A mere layer of red muscular MORBII* STATES OF THE MEMBRANES OP

structure covered the internal and external parts
of the heart and the columnae carnete : within
every spot was fatty matter."*

Rupture of the heart. — A degenerate con-
dition of the muscular tissue is the most com-
mon cause of rupture of the heart: the states
last described are those in which it most fre-
quently occurs; they correspond to the senile
softening of Blaud :f the wall literally gives
way at a certain point, and a laceration fre-
quently to a very trifling extent is found in that
situation on examination after death : in some
cases, moreover, several ruptures are found in
the wall of the same cavity, and sometimes
the rupture is very extensive, or it is large in-
ternally and small externally, or vice versa.
Any of the cavities may afford examples of
this form of rupture, but the left ventricle is
by far the most frequent seat of it, as may be
understood from the following numerical state-
ment by Ollivier: " out of forty-nine cases the
rupture was seated in the left ventricle in thirty-
four, in the right ventricle in eight, in the left
auricle in three, and in two cases the ventricles
presented several ruptures. In these cases
the apex was the situation of the rupture in
nine ; in the rest the rupture took place near
the base. Rupture, however, may occur in
a healthy state of the organ, from violent bodily
exertion ; of this a remarkable example was
afforded in the case of one of \Vhi thread's
draymen, who in attempting to raise a butt of
porter, fell dead, from a large laceration of the
left ventricle, the structure of which was per-
fectly healthy. I had lately an opportunity of
examining the preparation of this heart in the
Museum of Guy's Hospital.

Rupture is also found to ensue upon abscess
in the heart, or upon ulceration and conse-
quent perforation ; it is sometimes caused by
dilatation of it, and sometimes by contraction
of one or more of the orifices.

Partial rupture may occur, i. e. the external
fibres may be ruptured to a certain depth,
without penetrating the cavity, or the internal
ones may be similarly torn, the exterior being
unaffected. A more remarkable kind of par-
tial rupture is that in which the carneae co-
lumnae or chordae tendineae are engaged. Cases
of this form of rupture seem to have been
detailed first by Corvisart, who attributed the
nipture to violent efforts. Other cases have
been subsequently recorded by Cheyne, Adams,
and Townsend. In Dr. Cheyne's case, " the
internal surface of the left ventricle was much
inflamed, several irregular excrescences were
attached to the mitral and semilunar valves.
The chordae tendinese, which connected the
larger portion of the mitral valve to the wall
of the left ventricle, were torn off just at the
point of their insertion into the edge of the
valve; four of these ruptured tendons hung
loose into the ventricle."]:

* Croonian Lectures on the Heart, p. 32.
t Blaud, B.bl. Med. an. 1820.
j Dublin Hosp. Rep. vol. iv. On the subject of
rupture of the heart the reader may consult Olli-

THE HEART.

I. Morbid stctteaofthe pericardium. — 1 . Pe-
ricarditis. The morbid changes of the serous
pericardium which most frequently come under
the notice of the anatomist, are those
which are consequent upon inflammation.
What the alterations are which indicate the
first onset of inflammatory action it is not easy
to determine precisely, as the opportunities of
inspecting the parts in this early stage of peri-
carditis are extremely rare. The following,
however, may be stated as indicative of the
earliest period of pericarditis. The natural
exhalation becomes diminished or totally
suppressed, and consequently the surfaces of the
membrane do not present their usual moist
appearance ; the visceral layer of the pericar-
dium is not so transparent as in the natural
state, and several red points, which to the naked
eye appear like extravasations of blood, are
manifested on a considerable portion of the
membrane. These spots, however, are not
extravasations, but when examined with a lens,
they are seen to be produced by a close net-
work of extremely minute capillary vessels;
as inflammation advances these spots increase
in number, neighbouring ones coalesce, a more
or less diffused redness is produced, as well
from vessels subjacent to, as in the membrane,
the membrane becomes less and less transparent,
and now an exudation is distinctly formed on
its surface of a very soft semifluid material (co-
agulable lymph), which, on looking carefully
along the inflamed surface, is seen to be de-
veloped in minute granules. The further pro-
gress of the disease is characterised by the
increased deposition of this plastic material,
and the effusion of a straw-coloured serous
fluid into the bag of the pericardium. These
morbid changes, of course, vary in extent ; but
it is not uncommon to find them extending
over the greatest part or even the whole heart,
so that in some cases a second complete enve-
lope is formed for the heart between the visce-
ral and parietal layers of the serous pericar-
dium ; on the other hand a very circumscribed
spot may be occupied by these changes, not ex-
ceed ing a half-crown or a crown piece in circumfe-
rence ; but we seldom or never have opportu-
nities of seeing the disease on this limited
scale in so early a stage, and judge of its
occurrence only from the existence of alterations
which may justly be regarded as its sequelae.

Certain" varieties are observed as regards the
form assumed by the lymph, and the quantity of
the fluid effused in this disease. The lymph
varies in its characters ; almost always depo-
sited in a membranous form, it is sometimes
quite smooth and uniform on its free sur-
face; at other times it is rough, and hangs in
flocculi into the fluid contained in the sac of
the pericardium ; again it presents a reticulate
appearance, compared by Corvisart, Laennec,
and Berlin, to the inner surface of the second

vier's article (Coeur Rupture) in Diet, de Med.,
Townsend in Cyclop. Pract. Med. vol. iv. p. 630.,
and Bouillaud's work.

2 17 2

644

ABNORMAL CONDITIONS OF THE HEART.

stomach of the calf, or, as Laennec suggested,
to the appearance produced by quickly se-
parating two slabs of marble which have been
applied together, with a small quantity of
butter or some similar substance between them.
The depth of the depressions in this false
membrane varies with the thickness of the
membrane itself. Shortly after its deposition
the lymph is very tender and easily torn, but
when it has been some time deposited, it ac-
quires a considerable power of resistance. The
effused fluid in pericarditis varies likewise in
quality and quantity. In some cases it is
whey-coloured, with flocculi of lymph floating
in it ; in others it is of a yellowish colour, ap-
proaching that of pus, and in some degree of
the same consistence : sometimes it is of a
brownish colour. When it is in very small
quantity it is less turbid ; when in large quan-
tity it resembles whey. In some cases the
quantity is very considerable. It may be said
to vary from a few ounces to more than a pint;
but in some extreme cases it goes even far be-
yond this; thus Corvisart mentions a case in
which the effused fluid amounted to eight
pounds, and in one described by Bertin the
distended pericardium formed a bag seven or
eight inches broad, five deep, and ten or eleven
in height. Sometimes the effusion cannot be
distinguished from pus.

The coagulable lymph is effused not only on
the free surface of the visceral layer of the pe-
ricardium, but likewise on that of the parietal
layer. That which is effused upon this latter
layer is, however, often much thinner and
more delicate. These two deposits of lymph
are continuous with each other at the reflection
of the serous pericardium from the great vessels
on to the muscular fibres. When the effused fluid
hasbeen removed by absorption, the two pseudo-
membranes being brought into apposition with
each other, areas it were glued together; they
become organised by new vessels shooting into
them from the cardiac vessels, and at length
they assume the form of cellular tissue. The
cavity of the pericardium thus becomes oblite-
rated by the development of this new cellular
tissue. The adhesions thus formed are more
or less extensive according to the extent of the
primitive inflammation, so that in some cases
the pericardium is universally adherent to the
heart; in others the adhesion is circumscribed
within very narrow limits ; in this latter case
the new cellular membrane is often of conside-
rable length, inasmuch as the spots to which it
adheres on the opposed layers of serous mem-
brane do not at all correspond ; but when the
adhes.on is extensive, the connecting cellular
membrane is generally short and close, so much
so in some cases that the pericardium and heart
appear to be completely identified. The mus-
cular substance subjacent to the inflamed peri-
cardium sometimes appeais to participate in
the inflammatory process, acquires a greater
hue of redness than is natural, and becomes
softer, and loses to a greater or less degree its
cohesive power.

Such is the ordinary course and termination
of pericarditis. Every museum contains many

specimens illustrative of the different stages of
this disease. The cellular adhesion which fills
up the pericardial cavity occasionally exhibits
further alterations. Sometimes we find it infil-
trated with serum, and quite anasarcous; at other
times asero-purulent or purulent fluid is effused
into it. It becomes condensed, fibrous in its
character; or cartilaginous or fibro-cartilaginous
or even osseous plates are formed in it, which
sometimes are of so large a size that the heart
appears as if enveloped in an osseous case.
This cartilaginous or osseous deposit, however,
sometimes takes place in the fibrous pericardium.
Dr. Hodgkin mentions a case of osseous trans-
formation so extensive that the osseous plate
occupied a large portion of the base of the
heart, where it formed a complete bony ring,
the apex of the heart, however, beins left at
liberty. A somewhat similar case is recorded
by my friend Mr. Smith. " The pericardium was
united to the surface of the heart by close and
old adhesions, and around the base of the
organ bony matter was deposited in considera-
ble quantity, apparently between the two serous
layers of the pericardium; it formed an osseous
belt surrounding nearly theentireofthebase of the
heart ; its surface flat and rough, its margin
irregular and waving, and its average breadth
about one inch. This bony girdle penetrated
into the substance of the ventricles, and reached
in some parts almost to the lining membrane of the
latter."* In Mr. Burns' case the whole extent
of the pericardium covering the ventricles, and
the ventricles themselves, except about a cubic
inch at the apex of the heart, were ossified and
firm as the skull.

White spot on the heart. — There is no ap-
pearance with which anatomists are more
familiar than the white spots on the heart. A
single portion of white opaque, or nearly
opaque membrane, situated on the anterior part
of the right ventricle nearer its apex tlum its
base, and varying in circumference from that of
a shilling to that of a half-crown, as thick as
the pericardium itself and sometimes conside-
rably thicker, constitutes what I have most fre-
quently seen. They may be found, however, oc-
casionally on the posterior surface as well as the
anterior, on the left side as well as the right,
on the auricles as well as the ventricles. On
careful examination, it is evident that the opa-
city is occasioned by an adventitious deposit.
This deposit, in a great number of the cases
in which 1 have examined it, consisted of a
thin lamina of condensed cellular membrane
adherent to the free surface of the visceral
layer of the pericardium, which could easily be
dissected off, and which I have often peeled off
with my fingers, leaving the pericardium appa-
rently as if no deposit had been found there.
Dr. Baillie, and more recently Laennec and
Louis, testify to the facility with which it
may be dissected off'. Others, however, affirm
that the deposit is most frequently under the
serous covering of the heart, and consequently
in the subserous cellular tissue by which that
layer is connected to the heart. Corvisart

* Dub. Journ, vol. ix. p. 419.

ABNORMAL CONDITIONS OF THE HEART.

645

maintains this opinion exclusively, and Dr.
Hod^kin states his belief that in by far the
greater number of cases these patches depend
on a deposit on the attached surface. This
writer adds — " From the circumstance of their
being often found immediately under the ster-
num, and from their being occasionally met
with on other parts of the heart, to which a firm
and resisting body has been unusually opposed ;
as for example, when a bony deposit has taken
place beneath the reflected pericardium, or
when an uneven and remarkably indurated
liver has, even through the diaphragm, presented
an unequal pressure against a particular part of
the heart, I have thought it probable that such
pressure, aided by the movements of the heart
itself, may have led to the production of these
spots. These formations may certainly take
place at a very early period of life. I have
met with one rather loose and thick, but in
other respects perfectly resembling those found
in the adult, on the right ventricle of a child
only ten weeks old. Similar thickening of the
close pericardium sometimes marks the course
of the coronary arteries and their branches ; and
this circumstance amongst others tends to con-
firm the idea which I entertain as to its mode
of formation."*

Mr. T. \V. King, in an Essay on this subject
in the sixth number of Guy's Hospital Reports,
records a very remarkable example of the opa-
city. The patch, " a uniform whitish thicken-
ing of the close pericardium," nearly equalled
in extent the anterior surface of the right ven-
tricle, and was extended over the anterior sur-
face of the pulmonary artery as far as its bifur-
cation. Two similar patches were found on
the under surface of the ventricle. Mr. King
inclines to the opinion that this deposit is
seated in the proper tissue of the serous mem-
brane, and considers it always inflammatory
and pretty constantly the effect of friction and
irritation. " The situation of these patches,"
observes Mr. King," whenever they occur, im-
plies to my mind a egree of attrition at the
part more than belongs to the pericardium ge-
nerally. They are found on the surface of the
right auricle almost as frequently as on the ven-
tricle, but not in so morbid a form ; and much
more divided, even minute, and often clustered
like the rippling of the sand at ebb-tide. One
is not unfrequently seen along the anterior
face of the great pulmonary artery. All these
relate to the right side of the heart, which all
pathologists are aware is often, and more than
the left, the subject of distensions. The
patches may occasionally, perhaps, be seen on
any part of the close pericardium. I have
seen them behind the left pulmonary veins;
but, omitting this instance, the next most com-
mon appearance of the kind is that of length-
ened, narrow, winding, and even branching
lines immediately over the great vessels of the
ventricles whenever they are the subject of con-
siderable dilatation. Here, also, we have evi-
dence of a disproportionate space of attrition,
resulting from undue prominence."

»Lect. on Morb. Anat. of serous membranes, p. 98.

I am not aware of any well-authenticated
instance of ulceration or gangrene of the peri-
cardium. In cases of ulcerative perforation of
the heart, it may be said, however, that the pe-
ricardium ulcerates as the other parts do.

Tubercular formations. — Tubercles, whether
cancerous, me'lanotic, or scrofulous, are formed
subjacent to either serous layer of the pericar-
dium ; sometimes, and most frequently they
are deposited between the visceral layer and the
heart, or they may be found between the fibrous
pericardium and the parietal aspect of the se-
rous layer.

Cysts. — The serous cysts which are described
as occurring in the heart are sometimes formed
immediately subjacent to the serous membrane,
and project into the pericardial sac. Accord-
ing to Andral they occur most frequently in
this situation. Similar cysts have been found
between the fibrous pericardium and its serous
lining.

Hy drops pericardii or hy draper icardium. —
This disease consists in an undue accumulation
of fluid in the sac of the pericardium. The
fluid is either simply serous, of yellowish cha-
racter, or it may be of a brownish or reddish
hue. In quantity it rarely exceeds two pints.
The effusion is not generally attended with any
evident morbid change either of the heart or its
membranes, excepting that in cases of some
standing, the heart seems somewhat atrophied,
and the pericardium has lost its perfect trans-
parency.

Pneumopericardium. — The presence of air in
the pericardium, as the effect of morbid action
during life, must be very rare. Laennec, how-
ever, speaks very confidently of its existence.
" Sometimes," he says, " the air is combined
with a liquid, and this is by much the most
frequent case ; at other times the pericardium
is distended by air alone." Could the cases of
dry pericardium related by Baillie have been
produced by the developement of air in its cavity ?

Morbid states of the endocardium. — 1. En-
docarditis. The lining membrane of the heart
is so similar in its structure and properties to
the pericardium, that their morbid states are
very similar likewise. The constant contact of
the blood with the former membrane serves,
however, to modify considerably the anatomical
characters of disease in it. \Ve want, I think,
satisfactory proofs of the changes induced by
endocarditis in its earliest stage; these changes
are described to be, redness of the membrane,
with a more or less thickened or swollen condi-
tion of it; but the redness is not the result of
capillary injection, but seems to be a stain on
the membrane, the result of contact with the
blood. The stain is not merely superficial, but
has sunk into the substance of the tissue, and
it cannot consequently be washed off.

The lining membrane of the heart is often
found stained of a red colour as a post-mortem
result ; and this is invariably the case in hearts
examined after putrefaction has commenced.
The blood contained in the heart has begun to
alter, various gases are given out, and the inter-
nal membrane more readily imbibes the colour-
ing matter that is brought in contact with it.

646

ABNORMAL CONDITIONS OF THE HEART.

Can this redness be distinguished from that
which is consequent upon inflammation ? It
seems to me that there is no anatomical charac-
ter by which the true nature of the discoloration
can be proved. The anatomist must be guided
in coming to a conclusion upon the question
by concomitant circumstances, of which the
time which has elapsed after death, the quan-
tity and quality of the blood in the heart, and
the state of the other organs or textures of the
body, are the most important. If the examina-
tion has been made soon after death, that is,
within twenty-four hours, if the blood in the
heart presents no undue predominance of co-
louring matter, nor has undergone any decom-
position, and if the other tissues retain their na-
tural state, and show no unusual tendency to
putrefaction, the redness may be inferred to be
morbid and inflammatory ; but this inference is
confirmed with the utmost degree of certainty,
if the redness is accompanied by an effusion of
coagulable lymph or of pus, and by an unequi-
vocal thickening or swelling of the endocardium
itself; sometimes, also, as Bouillaud remarks,
the adhesion of clots, resembling the buffy
coat of blood, are among the anatomical
.signs of inflamed endocardium. The in-
flamed endocardium is, according to Bouil-
laud, more easily detached from the internal
surface of the heart, owing in all probability to
the subjacent cellular tissue having lost its
force of cohesion, and become fragile.

Lymph effused on the endocardium does not
generally take the laminated form as in pericar-
ditis, nor do we find it covering an extensive
surface, as in that disease. Small patches of
membranous lymph are sometimes met with
here and there, either on the surface of the
valves or over some part of one of the cavities;
at other times it assumes a granular or warty
form, or it projects in papilliform or conical or
globular masses from the surface of the valve.
Thus are formed the vegetations which are
among the most frequent valvular diseases, and
which offer the greatest impediments to the
adequate action of the valves. When examined
recently after their formation, they present all
the characters of the albumino-fibrinous exuda-
tions of serous membranes, their form being
determined by the frequent changes of relation
which the inflamed surface undergoes in the
heart's action, as well as by the current of
blood from the heart continually flowing over
it.

The further progress of inflammation of the
endocardium induces thickening of the mem-
brane or of the valves, organization of the effu-
sed lymph, which thus becomes more firmly
adherent to the surface on which it had arisen,
and induration of the membrane from cartilagi-
nous or calcareous deposits, which however are
generally met with within the fold of membrane
constituting the valves, and more intimately
ronnected with the interposed fibrous than with
the serous membrane.

When inflammation of the folds of endocar-
dium forming the valves runs its course with
great rapidity, it may induce destruction of
them -to a greater or less extent. Softening,

ulceration, and rupture of the affected valve are
very speedily produced. " The ruptured and
ulcerated portions," to borrow Dr. C. J. Wil-
liams's description, " are found loaded with
ragged, soft, fragile vegetations, more or less
tinged with blood, and these are also some-
times seen adhering to adjacent parts where the
endocardium is entire. The remaining parts of
the valves are much thickened and opaque yel-
lowish white, with a pink hue; and pink patches
are often seen in the aorta with atheromatous
thickening." Sometimes a valve is perforated
in its centre by ulceration, and the circumfe-
rence of the perforation is surrounded by warty
vegetations.

It is well known that the endocardium of
the left side is much more liable to disease than
that of the right, whether as regards the valvu-
lar portion of it or that which lines the interior
of the heart. But the views of Bichat and
others, who denied the occurrence of disease
on the right side, have been abundantly refuted
by modern observations.

Chronic valvular diseases. — Chronic endocar-
ditis affects the valves of the heart in such a
manner as in all cases to occasion more or less
obstacle to the flow of the blood from the ven-
tricle or auricle. Sometimes, however, the
disease is not of a kind to interfere with the
valvular action and to permit regurgitation ; but
at other times the disease has gone so far in
one or more of the valves as to prevent its con-
tributing to the perfect closure of the orifice,
and consequently to destroy the power of the
valves to oppose regurgitation. Hence the
subdivision proposed by Dr. Williams, for val-
vular diseases, into those which more or less
obstruct the current of the blood in its proper
channel, or the obstructive, and those which
permit it to pass in the reversed direction, or the
regurgitant. Thickening of a valve, so as to
prevent its complete apposition to the internal
surface of the artery or of the ventricle, will oc-
casion obstruction, the degree of which will
depend on the degree of perfection of apposi-
tion with which the valve may be applied to
the neighbouring surface; on the other hand,
the degree to which regurgitation is permitted
will depend upon the degree of induration of
the valve, and the want of extensibility which
it manifests.

Thickening of the edges of the valves is
among their most common diseased states; the
attached margin or base of the valve is also very
frequently the seat of thickening, and in both
these situations the fibrous tissue seems to be
engaged principally in the disease. The inter-
vening portion is generally affected as a conse-
quence of the extension of the disease from
these margins. In such cases the thickening
arises from a deposit between the layers of the
fold forming the valve; in other cases the thick-
ening is produced by a deposit upon the surface
of the valve. On the aortic valves this deposit,
when on the ventricular surface, is apt to assume
the form of two crescents corresponding in po-
sition as well as form to the two crescentic por-
tions of fibrous tissue within the fold of mem-
brane by which the valve is formed. This fact

ABNORMAL CONDITIONS OF THE HEART.

647

was, I believe, first pointed out by Dr.
Watson.

Ossification most commonly manifests itself
in the fibrous zones which surround the heart's
orifices, and therefore it is chiefly to be found
at the bases of the valves ; but it likewise ex-
tends towards their free margin ; and it too is
apt to be developed in the double crescentic
form in the aortic valves. Sometimes the ossi-
fication appears to involve principally the mar-
gin of the valve in whole or in part, and this
occurs much more frequently in the semilunar
than in the auriculo-ventricular valves. Osseous
deposits in the valves are either in the form of
thin calcareous laminae or spiculae, small round-
ed points, or large masses more or less rounded,
and often projecting to a considerable extent
beyond the surface of the valve.

The effect which the developement of these
new deposits on or in the valves has upon their
size and form, as well as upon the size and form
of the openings which the valves surround, is
very various and very interesting to the patho-
logist. The almost invariable alteration which
they produce in the size of the valve is to
shorten it or diminish it in depth ; the valve
becomes corrugated, its free margin thickened,
or folded in the direction of the current, or in
an opposite direction, the whole valve present-
ing a curled appearance. The orifices are
always more or less diminished in size when
one or more valves have acquired this rigid,
inelastic, and contracted form ; the diminution
is produced by the valve or valves always pro-
jecting more or less into the orifice; but the
greatest degree of narrowing of the aperture is
occasioned by the adhesion of two or more
valves at their free margins ; and in this way,
as may be readily conceived, an orifice be-
comes sometimes almost completely obliterated.
The same causes change the shape of the orifi-
ces, and consequently we find altered size and
shape constantly going together. It is in the
left auriculo-ventricular opening that these
changes are most commonly seen ; they rarely
occur to so great an extent in the aortic orifice,
and seldom at all in the apertures of the right
heart. My friend, Mr. Adams, has made some
most valuable remarks upon the contracted au-
riculo-ventricular orifice of the left side, in his
very valuable paper on diseases of the heart in
the Dublin Hospital Reports. His description
of the anatomical characters of the disease cor-
responds so exactly with what I have many
limes witnessed, that I cannot refrain from
quoting it. " When the dilated (left) auricle
is cut into and cleared of the blood it contains,
at its lowest part, instead of the mitral valve, a
concave membranous septum of a yellow colour
is seen, which is perforated by an oblong
fissure, about half an inch in length, and one or
two lines broad ; this fissure I have observed
to be always obliquely situated, and to run
parallel to the septum of the ventricles ; it ge-
nerally is of a semilunar form, the concavity of
the curve looking towards the root of the aorta,
the convexity backwards ; the first formed by
the larger portion of the mitral valve, the latter
by the smaller ; the edges of this oblong fissure

are generally studded with long depositions ;
viewed from the left ventricle, the membranous
septum is convex, and the angles of the fissure
are connected by shortened chordse tendineae,
with two very thick fleshy columns, the one in
front, the other behind."

Dilatation of the valves. — We sometimes
find the valves of the heart in a dilated or aneu-
rismal state. Laennec has placed on record an
example of this affecting the mitral valve :* " A
little pouch, half an inch long and more than
four lines in diameter, projected on the supe-
rior surface of this valve," i. e. into the left
auricle. Mr. Tlmrnam has appended the
detail of several cases to his memoir already
quoted on Aneurisms of the Heart.f He de-
scribes a specimen, preserved in the Hunterian
Museum, affording an example of four aneuris-
mal pouches of the tricuspid valve. The same
writer likewise records a case in which there
was congenital absence of one aortic valve ; the
two, which were present, were thick and fleshy,
and rough on their ventricular surfaces. The
edge of the one was smooth, that of the other
rugged ; there was a deposit of ossific matter at
their points of attachment. From the ventricu-
lar surface of the valve with the smooth border,
there projected a little bag that would hold a
swan-shot, and which opened by a little round
mouth on the aortic surface of the valve. It
had two little slits in its most depending por-
tion, and was evidently formed by a dilatation
of the valve itself."

Atrophy of the valves. — We have a familiar
instance of atrophy of valves in the case of the
Eustachian valve, which undergoes as it were a
sort of natural atrophy from the commencement
of extra-uterine life. The valve becomes cri-
briform, and the holes by which it is pierced
gradually enlarge and coalesce, and in this way
the valve is worn away. We often find one or
more of the semilunar valves perforated by
openings of a similar kind, without the co-ex-
istence of any other disease ; the margin of the
opening is always smooth, and the valve itself
thinner and more flaccid than is natural. Ac-
cording to Dr. Williams, the wasting affects the
posterior portion of the mitral valve, " the
membrane of which is often annihilated by it,
the cords being inserted directly into the auri-
cular ring." The anterior lamina is also occa-
sionally found much shortened, and without
those fine thin expansions of membrane which
commonly unite the cords to each other, below
their insertion into the thicker part of the
valve.

Entozoa in the heart. — The occurrence of
entozoa in the human heart must be considered
to be extremely rare, at least the cases on record
which may be depended on are very few.
Andral states that he found the cysticercus
once in the human heart, but has seen it fre-
quently in the hearts of measly pigs. Many
examples are mentioned by various authors of
ascarides, filariae, cercariae, and other entozoa
in the hearts of dogs and many other of the in-

* Quoted in Bouillaud's work, t. ii. p. 510.
t Loc. cit.

648

ANIMAL HEAT.

ferior animals, Mammalia, as well as birds,
reptiles, and fishes.*

States of the blood in the heart after death. —
What appears to be the natural state of the
contents of the heart after death is as follows.
The right auricle contains a coagulum of dark
blood, and the right ventricle contains a similar
one, of less size ; a very small quantity of coa-
gulum or of fluid blood is found in the left
cavities, and it is not uncommon to find a coa-
gulum extending into the aorta ; white coagula
are often found in these cavities. Sometimes
these coagula, especially at the right side,
adhere closely to the wall of the cavity in which
they are situated, and appear as it were
moulded upon it, sinking into the interstices
between the fleshy columns, so as to render it
difficult to remove them. The modification
which we most frequently meet with in this
state of the heart's contents, is that in cases of
asphyxia; affording, however, merely an in-
stance of aggravation, if I may so speak, of the
natural state ; the right cavities and the vessels
leading to and from them are gorged with dark
blood, liquid or coagulated, while the left cavi-
ties are nearly empty. Such states of the
heart's cavities, it is obvious, are formed in
articulo mortis. Fibrinous masses, either mixed
with or deprived of the colouring matter of the
blood, have been many times found, which it
cannot be doubted were formed in the heart some
time prior to death, and probably gave rise to
symptoms of a serious nature; these are the
true polypous concretions of the heart. The
manner in which Mr. Allan Burns, one of our
earliest British writers on the heart, explains
the formation of some of these concretions, is
deserving of attention. " If," he says, " we
strictly scrutinize all the reputed cases of poly-
pus in the heart, we shall reduce the real ex-
amples of this affection to a very limited num-
ber indeed. Still we shall leave a few, where
there is reason to believe that the concretion
had been formed a very considerable time be-
fore death : but it must be understood, that
these concretions are seldom found except in
hearts otherwise diseased. In health, the blood
does not tarry for any length of time in either
the heart or vessels; it is incessantly in motion,
circulating with greater or less rapidity, accord-
ing to the state of the heart and arteries. The
blood never in health remains so long in con-
tact with the surfaces of the heart, as to allow
of its being changed by their action. In some
diseases of this organ, irregular actions are ex-
cited by very trifling causes ; the blood stag-
nates longer in the heart than it usually does or
ought to do, while here it undergoes changes
by the reciprocal action of the blood on the
heart and the heart on the blood ; new organized
matter is deposited, and adheres to the parietes
of the cavity in which it is lodged. This con-
cretion slowly increases, the first particle acting
as the exciting cause for the deposition of the
second, and so on."

The strongest evidence of the formation of

* For a list of the references to such cases, see
South's edit, of Otto, Path. Anat. p. 293.

such coagula some time before death consists
in their being organised : in a case recorded by
the v\riter from whom the preceding passage
was quoted, a large and fully organised polypus
was found in the right auricle; its attachment
was by a rough surface to the musculi pectinati,
and its body hung down into the right ventricle.
It very much resembled a nasal polypus, and
it was so firmly fixed to the heart, that it allow-
ed the whole mass of the heart and a consider-
able portion of the lungs to be suspended by it,
without showing any tendency to separate. It
was pendulous and tapered from below up-
ward ; its structure was dense and lamellated,
and not a single red globule entered into its
composition." In this case, as in other similar
ones quoted by Andral, the adhesion of the po-
lypus seemed due to an inflammation of the
endocardium, either excited by the contact, or
before the formation of the coagulum. That
such coagula may be permeated by bloodves-
sels is proved by the cases of Bouillaud and
Rigacci, quoted by Andral: in the latter cases,
these reddish filaments passed from thecolumnae
carneae and entered the substance of the poly-
pous mass : they had all the appearance of
bloodvessels, and when injected with mercury
were found to divide into a number of small
branches that ramified through the substance of
the polypus. By careful dissection it was as-
certained that the tumour was formed altogether
of a mass of fibrine, such as is found in the sac
of arterial aneurisms Pus is occasionally found
in the centre of these fibrinous concretions, but
whether carried to the heart in the blood, and
accidentally enclosed in the coagulum during
its solidification, or formed in the coagulum by
some action within it, it is impossible to decide.
Osseous and cartilaginous deposits too have been
found in them, as in the case from Burns, in
which one of these polypi was ossified in several
points, and so perfectly organized that on inflat-
ing the coronary vein, a number of minute ves-
sels on the surface and in the substance of the
tumour became distended with air.

( R. B. Todd.)

HEAT, ANIMAL.— Judging merely by
our sensations, we should infallibly conclude
that our bodies undergo very considerable
changes of temperature. This belief was in-
deed necessarily entertained previously to the
time when natural philosophy had discovered
a means of ascertaining the true state of the
matter. The application of the thermometer
has dissipated the error. But then error of an
opposite kind was run into, and the results of
a very limited number of observations led men
to conclude that the temperature of the human
body was invariable or nearly so. Still the
measures of temperature given by different ob-
servers did not perfectly accord, though each
presented his conclusions as the temperature
of the race. It was but reasonable to imagine
that these discrepancies arose not from any want
of accuracy in observation, but from diversities
inherent in the subjects observed. This is
now known to be the case. But though proofs
of this truth have been greatly multiplied, the

ANIMAL HEAT.

649

whole subject has never been presented in a
connected and systematic manner.

Since it is proved that the temperature of
the human body varies, we can only obtain an
approximation to its actual amount by taking
the mean of all the good observations that
have ever been made, being particularly care-
ful to include the extremes ; for a mean gives
but a very imperfect idea of a term that ought
to represent a variable number, if the limits
are not at the same time assigned and taken
into the account. The best observations of this
kind, provided they be sufficiently numerous,
will be those that have been made by the same
individual, inasmuch as there is great likeli-
hood that he will always have made use of the
same procedure and of the same instruments,
by which the results become more readily com-
parable one with another.

TEMPERATURE OF THE HUMAN BODY. —
In the following observations we shall make
use of the measures of temperature given by
Dr. John Davy. These amount to one hun-
dred and fourteen in number, and were made
on individuals of both sexes and of different
ages in three quarters of the world, in Europe,
Asia, and Africa, in different latitudes, under
various temperatures, and among individuals
of different races. But, as the knowledge of
the mean and extreme temperatures of the
body of man would have little value apart
from the statement of the circumstances and
conditions under which they were ascertained,
we shall at the same time give the ages of the
subjects and the temperature of the air at the
time of the observations.

The mean age of the subjects of Dr. Davy's
observations was twenty-seven years. The mean
temperature of the air was 23°, 3 c. (74° F.*) be-
tween the limits of 15°, 5 (60° F.) and 27°, 8
(82° F.). In these circumstances the mean
temperature of the body, which was always
taken in the mouth, was 37°, 7 (100° F.) be-
tween the extremes 35°, 8 (96°, 5 F.) and
38°, 9 (102° F.). The greatest difference in
one hundred and fourteen observations, there-
fore, scarcely exceeded three degrees. The
temperature of the human body thus obtained
might be considered as exact if the conditions
of age and external atmospheric temperature
approached pretty closely to their respective
means. This, in fact, was the case as regards
the first term, but not as concerns the second ;
for some of the observations were made under
very intense degrees of heat, such as 27°, 8 (82°
F.), but none at the opposite extreme, or at a
temperature which could be reputed cold, a
temperature of 15° (59° F.) being already suf-
ficiently agreeable. So that if the temperature
of the air influences that of the body, a ques-
tion which we shall examine by-and-by, the
mean which we have stated as the temperature
of the species would be too high.

It is of some consequence to pursue

* [The valuations according to Fahrenheit's scale
the editor desires may be regarded as mere though
close approximations to the indications according to
the centigrade scale.] — ED.

these inquiries among the lower members of
creation, among animals; and the writer to
whom we are indebted for the observations
quoted upon man has also made a great num-
ber upon the lower animals. We shall there-
fore continue to make use of this series of
experiments, as we have already made use of
that which bore upon man individually.

TEMPERATURE OF THE MAMMALIA. — The
observations here were made on thirty-one dif-
ferent species taken from among the principal
divisions of this class, and under a mean tem-
perature of the external air equal to 25° (77°
F.), between the limits of 15° (59° F.) and 30°
(86° F.).

The mean temperature of the body of the
Mammalia was 38°, 4 (101°, 10 F.), the max-
imum being 40°, 5 (105° F.), the minimum
37°, 2 (99° F.). The extent of variation con-
sequently presented by the Mammalia, 3°, 3
of the centigrade scale (6° F.), is nearly equal
to that exhibited by man. But there is this
difference between the two scales, that the
extremes and the mean in the case of man are
inferior to the corresponding terms in the case
of the Mammalia.

TEMPERATURE OF BIRDS. — The observa-
tions here were made on fifteen species in
different orders. The mean temperature of the
air was 26°, 1 (79° F.), between the extremes
15° (59° F.) and 31°, 5 (88°, 75 F.). The
temperature of the subjects of the experiments
offered a mean of 42°, 1 (107°, 86 F.), the su-
perior limit being 43°, 9 (111° F.), the inferior
37°, 2 (99° F.). The temperature of birds,
therefore, presents a <scale much more exten-
sive than that of man and the Mammalia,
amounting to as many as 6°, 7 degrees centi-
grade (12° F.). It also stands above both of
the others in the point of its mean, which is
higher by 3°, 7 (6° F. nearly) in its upper
limit, and 5° centigrade (about 9° F.) higher
in its lower limit. The lower limit, in fact,
corresponds very nearly with the mean term of
the heat of the Mammalia as exhibited in the
preceding scale. But in neither scale can we
say much in regard to the inferior limit, inas-
much as no observation was taken at a tem-
perature lower than that of fifteen degrees cen-
tigrade (59° F.).

When we compare the preceding statements
of the temperature of animals, it is apparent
that it varies but little between one species and
another of the same class. In passing to dif-
ferent classes, however, the difference becomes
very considerable, and though the observations
are here much fewer in number, they are per-
fectly satisfactory as regards the general result.

TEMPERATURE OF REPTILES. — From nine
observations made on members of the four
orders of Reptiles, Dr. Davy found, the ex-
ternal air having a mean temperature of 26°, 5
(79°, 75 F.) between the extremes 32° and 16°
(89°, 5 and 60°, 75 F.), that the temperature
of Reptiles was not higher than 28° (82°, 5 F.).

TEMPERATURE OF FISHES. — If from Rep-
tiles we pass to Fishes, corresponding and
even more remarkable differences are perceived.
Dr. Davy, indeed, gives the temperature of

650

ANIMAL HEAT.

no more than five species, but they belonged
to very different orders. The mean external
temperature being 22°, 3 (72°, I-.), that of
fishes was found to be but 23°, 2 (74° F.),
which is very little more than one degree cen-
tigrade higher. This difference becomes even
more striking, if possible, as we descend in
the scale of animals.

TEMPERATURE OF INSECTS. — From eight
observations on Insects of very dissimilar spe-
cies, the mean temperature of the air being
24° (75°, 5 F.), that of the insects was 24°, 2
(75°, 75 F.)

TEMPERATURE OF THE CRUSTACEA. — Two
species of Crustaceans, the cray-fish and crab,
presented a still more interesting phenomenon.
The mean temperature of the air was 24°, 4
(76° F.) at the time of experimenting, that of the
Crustacea 24°, 1, or somewhat lower than the
ambient medium. This we do not presume to
present as the rule, but we would say that the
temperature of the Crustacea is nearly equal
to that of the medium in which they are
plunged.

TEMPERATURE OF THE MOLLUSCA. — In
observing the temperature of a single Mollusc,
the common oyster, the temperature of the sea
being 27°, 8, (82° F.) that of the animal was
27°, 8 also.

It is obvious, therefore, that the differences
in the temperature of animals from reptiles
inclusively downwards is very inconsiderable.
All these animals, indeed, may he united
under a single category, and regarded as con-
stituting a single group characterised by the
state or degree of their temperature. The
same may also be done with reference to the
animals of the two higher classes, Mammalia
and Birds, which in point of temperature are
so nearly akin to each other.

There are consequently two grand divisions
of animals as regards temperature; the one
comprising the Mammalia and Birds; the
other including Reptiles, Fishes, Insects, Crus-
taceans, and Molluscs. The first is known
under the name of warm-blooded animals, the
second under that of cold-blooded animals.

To characterize the first under the view of
temperature, the mean of the temperatures of
the respective classes which compose it must
first be taken. From the experiments of Dr.
Davy the mean temperature of Mammalia ap-
pears to be 38°, 4 (101° F. )

that of birds 42°, 1 (108° F. )

Mean of both classes 40°, 25 (104°, 5 F.)

We may therefore say that the mean tempe-
rature of warm-blooded animals, including
man, surrounded by a moderate external tem-
perature is in round numbers 40° (104 F.)
between the limits of 36° and 44° (97° and
111°, 5 F.), by which we have a scale of dif-
ference amounting to 8° (about 14° F.).

The other class, that, namely, including the
cold-blooded animals, having no peculiar tem-
perature proper to them, may be characterized
in the following manner: — their temperature
differs little or not at all from that of the sur-

rounding media in which they live, when this is
at a degree which may be called moderate; so
that the differences are either inappreciable, or
do not exceed the limits of + 4 (39°, 50 F.).
We shall return by-and-by upon this character,
which requires development.

General conditions of organization in relation
with the production of' a greater or less
degree of heat.

So wide a difference in the heat of the two
categories of animals might lead to the pre-
sumption that there is also a very great dif-
ference in point of structure. If, indeed, this
relation exists and is easily detected, we may
be led to discover the general conditions of
organization upon which the production of
heat depends. Is there an organization com-
mon to Mammalia and Birds, distinct and
different from that belonging to the other
classes of animals ? This question can be an-
swered in the affirmative : there is a well-marked
diversity of organization which distinguishes
Mammalia and Birds from all other animals.

I. The most prominent feature of diversity
exists in the sanguiferous system, which is
divided through its entire extent into two dis-
tinct parts without direct communication be-
tween them, the heart presenting a complete
median septum, the bloodvessels in like man-
ner forming two systems of canals, which
have also no immediate communication in their
trunks.

II. This peculiarity of structure, which is
only met with among animals having warm
blood, is regularly associated with an organ
adapted for aerial respiration. The character
which distinguishes this respiratory organ from
the one met with among cold-blooded animals,
reptiles especially, is this, — that either in itself
or its appendices (the air-sacs of birds) it pre-
sents a much larger extent of surface in relation
with the air.

III. Warm-blooded animals are farther dis-
tinguished from the cold-blooded by important
modifications of the digestive canal. 1. The
first portion of the apparatus from the mouth
to the stomach is much more complex in them;
for instance, it presents either a much more
perfectly developed dental system, fitted to
divide the food, or a sac, as among birds,
fitted to macerate the aliment, and cause it to
undergo a kind of preparatory digestion before
it is passed to the stomach. 2. The stomach
is more distinct; either the entrance to and
exit from this pouch are better marked, being
often provided with a valve, as in the Mam-
malia, or its structure and form are more spe-
cial, as we observe it among Birds. 3. The
intestinal canal is much longer in the warm
than in the cold-blooded tribes.

IV. The nervous system presents diversities
still more important and well-marked. The
most striking character exists in the proportion
of the principal trunk of this system, and
especially of its encephalic extremity, which
is much larger in the warm than in the cold-
blooded animals.

The most remarkable structural conditions

ANIMAL HEAT.

6M

of warm-blooded animals, then, are four in
number, three of which are referable to the
organs of nutrition, the fourth to the nervous
system, which may be briefly related in the
following order: — 1. higher complication and
greater extent of the digestive apparatus; 2.
entire separation of the circulating apparatus
into two systems, the venous and arterial, with-
out direct communication between them ; 3.
organs of aerial respiration presenting a much
larger surface to the contact of the atmosphe-
rical air ; 4. a nervous system of which the
axis, and especially the encephalic extremity,
bears a very high ratio to the whole.

These structural characters determine the
following modifications of function. 1st,
The complexness and greater extent of the di-
gestive apparatus in warm-blooded animals
produces a more perfect elaboration of the
matters which serve for the formation of blood.
2nd, The arrangement of the parts of the cir-
culating system maintains the arterial blood
quite distinct from the venous, and in a state
of complete purity. 3rd, The respiratory ap-
paratus, by the great extent of its surfaces in
contact with the air, secures that its distinguish-
ing qualities be imparted in the highest pos-
sible degree to the arterial blood, which more-
over is elaborated in larger quantity. The
predominance of their nervous system, and es-
pecially of its encephalic extremity, renders
all the parts of the body much more excitable,
and gives the greatest energy to the nutritive
functions. The whole of these organic condi-
tions are mutually dependent, and may be
reduced to the expression of these two general
conditions: — 1st, the formation and distri-
bution of the arterial blood, the particularly
exciting find nutritive blood of the body ; 2nd,
the most powerful influence of the nervous
system.

As these characters of primary significance
in the animal economy coincide in Mammalia
and Birds with the greater production of heat,
and thus distinguish them from all other ani-
mals, it is probable that between these organic
conditions and caloricity or the power of
evolving caloric, there is a relation of the na-
ture of cause and effect. It is even almost
impossible that this should be otherwise than
as it has been stated ; for the characters of
organization and the peculiarities of function,
coincident with the greater evolution of calorie,
are almost the sole points of any importance
that distinguish warm from cold-blooded ani-
mals.

It is therefore nearly certain that the condi-
tions requisite to the production of heat must
exist within the circle of the functions which
we have described. And if this relation do
actually exist — as these functions are in a
state of mutual dependence, — it follows that
one of them cannot be modified, the others
remaining, so to speak, in the same condition,
without modification resulting in the calorific
capacity likewise. It is of great consequence
to verify this assumption, because if it be
well-founded, the probability already elicited
of the power of engendering heat being de-

pendent on the state of the functions in the
relations which have been indicated, becomes
matter of certainty. So that it is of the highest
import to follow the modifications of these
functions presented by animals and man in
order to compare them with the respective
varieties of calorific power presented by each.
And if we find that they coincide, and accord
with the principle established, we shall have
discovered the conditions of organization and
of function upon which the production of ca-
loric depends.

Conditions of organization and of func-
tions may be entitled the physiological causes
of the production of animal heat. If we
succeed in determining these, we ought to
rest satisfied. If, indeed, to this knowledge
we could add that of the immediate cause of
this phenomenon among animals, or what is
the physical cause, it would be a great gain
for science. This, accordingly, was the ob-
ject of the labours of the majority of phy-
siologists who have given their attention to the
subject of animal heat. But they could not possi-
bly succeed in their researches, for the simple
reason that natural philosophers themselves have
not yet discovered how heat is produced in the
inorganic world ; although indeed they have

Presumed that they were acquainted with it.
t is not to be wondered at, then, that attempts
have been made to detect this presumed cause
amidst the complicated phenomena of life.
But natural philosophers have lost confidence
in the theory which they had formed, and are
searching for a new one. Meantime they are
doing what ought always to be done under
such circumstances ; they are studying with
care the various conditions and circumstances
in which it is produced ; determining these
with precision, and measuring with rigour the
quantity of heat produced. Of late, therefore,
many distinguished physiologists have entered
on the same path, and by experiment have
endeavoured to ascertain the physiological con-
ditions of the production of heat. But if
their predecessors have not attained the object
they had in view, they have nevertheless ren-
dered very essential services to science ; for in
searching after the physical cause of heat, they
have determined with precision the physiological
conditions of the production of animal heat,
which are of very great importance. Inde-
pendently of the simple observation of the actual
temperature of animals, the labours of physio-
logists on this subject consist almost entirely
of experimental facts, that is to say, facts
created by science.

But there is one source of inquiry into the
laws of animal heat which has been little
dipped into, although it is beyond all comparison
the most abundant. I allude to that presented
to us by nature in the all but infinite variety
of modifications of organization and pheno-
mena exhibited in the vast chain of animated
things, not only in the diversities of species,
but also in the varieties of age and constitution,
and the changes induced by the states of health
and disease. In making this an object of
peculiar study, we become acquainted with

652

ANIMAL HEAT.

the greatest possible number of phenomena
connected with animal heat ; and in determin-
ing the physiological conditions of its produc-
tion, we shall lay up a store of theoretical
knowledge peculiarly applicable to practice,
the end and object of all physiological inves-
tigation.

The means of comparing these modifications,
however, and of judging of their importance
are not always easy. We shall do as much as
the actual state of our knowledge permits if
we inquire first, by what means we can ap-
preciate the modifications relative to the arterial
blood.

1. As regards the quantity of the arterial
blood, we shall view this point of the inquiry
less with reference to the whole amount of
blood circulating in the body, than to the
quantity which is formed at a time, as it were,
in the lungs; because it is evident that if the
arterial blood influences the phenomenon of
heat, the more that is formed at any given
time the greater ought to be the direct or in-
direct influence upon the production of heat.
«. As it is not always possible to have a direct
and precise measure of the relative quantity of
blood in the organs, we must be content with
an approximative mode of estimating this,
which consists in ascertaining in what degree
the lungs are loaded with blood, b. An aid to the
judgment may also be derived from the relative
size of the lungs, the tissue being presumed to
be nearly alike throughout their entire mass.
c. With an equal volume of lungs, the greater
or less compactness of the tissue must be taken
into the account. The closer the tissue is,
the more are the surfaces in contact with the
air multiplied, d. The extent and rapidity of
the respiratory motions form another element
in the calculation ; for to increase the amount
of relation with the air is analogous to the for-
mation of a larger quantity of arterial blood
within a given time.

All the foregoing data refer to the absolute
or relative quantity of arterial blood. But
there are other particulars connected with its
constitution which it is necessary to mention.
The blood, for instance, is composed of a fluid
and solid part, the latter existing under the
form of globules. It is obvious that the fluid
is not the characteristic part of the blood, in-
asmuch as this is met with elsewhere, whilst
the globules of the blood are only known as
constituents of this fluid. The arterial blood
consequently ought to have qualities by so much
the more distinctive and energetic as it con-
tains a larger proportion of globules. Now
this is a character that may be appreciated with
exactness, and measures of it have been given.
But the globules of the blood are not in-
variably of the same nature, a fact which may
be judged of by outward and very obvious and
appreciable characters, namely, size and form.
The smallness and more or less perfectly sphe-
rical or rounded form of the blood-globules
distinguishing animals with warm blood, co-
incide in the Vertebrata with a higher capacity
to produce heat. For we do not institute this
comparison here save in reference to animals

included in this division, inasmuch as the cha-
racters of the blood have only been studied
under these relations among them. We shall,
therefore, hold the energy of the calorific power
to be connected with the smallness and rounded
form of the globules of the blood in vertebrate
animals.

2. The materials of the blood being sup-
plied by the digestive apparatus, we might
judge, all things else being equal, of the per-
fection of the blood by the perfection of this
apparatus. But there is likewise a necessary
co-relation between the result of the function,
and the aliment; for instance, when the ap-
paratus shall be found nearly alike in any two
cases, the difference of food necessarily in-
fluencing the qualities of the blood, the com-
parison must be established, every other cir-
cumstance being equal, according to the higher
or lower nutritive qualities of the food.

As the use of the arterial blood is to excite
and nourish the different parts of the body,
there will be a necessary correspondence be-
tween the blood and the result of the nutrition
which may become manifest in the nature and
quality of the tissues. And in this case it
would be fair to make use of these characters
of tissues to form an estimate of the nature of
the blood in reference to its aptitude to pro-
duce heat ; and this we shall accordingly do.
But even in the event of all these characters
failing us, there is another source whence we
can derive comparative measurements, which
are susceptible of very rigorous application.

Since it is necessary that the venous blood
should pass through the lungs in order to be-
come arterial from contact with the air of the
atmosphere, it is obvious that it cannot un-
dergo any change in its constitution without
the air at the same time suffering a change.
That the air is altered by the respiratory act is
well known to all, and as there is a necessary
co-relation between the blood aerated during
respiration and the air which it alters, the
amount of alteration undergone by the one
may be estimated from the change suffered by
the other. The quantity of air altered by re-
spiration, all other things being equal, ought
to be found in relation with the production of
heat.

The different characters which we have men-
tioned all refer directly or indirectly to the
blood. There still remains one of another
order which may also serve us as a guide in
making comparisons in reference to the pro-
duction of heat. The allusion here made is
to the nervous system, the superior value of
which in warm-blooded animals has already
been commented on. It is thus, then, that we
may assume the predominance of the nervous
axis, and particularly of its encephalic ex-
tremity, as a condition favourable to the pro-
duction of heat, and which, in circumstances
of parity among the other conditions, must
tend to the production of a greater quantity of
heat. Such are the modes of proceeding which
we shall follow in investigating the modi-
fications of the organic conditions and of the
functions which coincide with the greater evo-

ANIMAL HEAT.

653

lution of heat. To ascertain whether this
coincidence is to be viewed as being in the
mutual relation of cause and effect, it imports
to know whether or not their variations are in
relation with those of the heat produced. If
they coincide whenever we compare them, pro-
vided these comparisons are but sufficiently
numerous, we shall be safe in admitting a
necessary connexion between them. We were
led to the relation which engages our attention
in the course of our comparisons of warm-
blooded animals with those having cold blood
considered in general. Let us now enter upon
a comparison of the same kind, but more par-
ticular, whilst we take account of the most
important subdivisions of these two great
groups in order to verify our first inductions.

We shall first compare Mammalia and Birds
to determine which of the two classes, in con-
formity vvith the principle to which we have
been led, has its organization most favourable
to the production of heat.

The lungs of Birds, although smaller, are
more loaded with blood than those of the
Mammalia, and are in communication with ex-
tensive air-cells, spreading all through the body
and even penetrating into the cavities of the
bones, so that the air may be said to penetrate
the body generally, and to be in contact with
the ramifications of the aorta as well as with
those of the pulmonary artery ; the blood of these
animals is therefore in the most extensive rela-
tion imaginable with the air of the atmosphere.
Again, if the nature of the blood of Birds be
considered, independently of this extensive
relation with the air, the organic condition here
will not appear less favourable to them. The
globules of this fluid, indeed, are a little larger
and less spherical than in Mammalia, which is
a disadvantage ; but the proportion they bear
to the fluid part is so favourable to Birds that
this circumstance must give them immensely the
advantage in reference to the character which
engages us. With regard to the nervous sys-
tem, if the encephalic extremity is developed
in a minor degree in Birds, their circulating
and respiratory systems act with greater quick-
ness. Lastly, and as an effect of the whole of
these conditions, the consumption of air is much
greater among Birds than among Mammalia.

From all that precedes, it follows, if the
principles already laid down be correct, that
Birds ought to produce the greatest quantity of
heat; and this is actually the case, as we have
seen when we were speaking of the actual tem-
peratures of the different classes of animals —
the mean temperature of the Mammalia is
38°, 4 (101° F.), that of Birds 42° 1 (108 F.).
Here, then, is a powerful confirmation of the
relation which we have recognized between the
conditions of the organization and the produc-
tion of heat; it is of so much the more value
as the relation being based on the comparison
of two classes so numerous, the verification is
made on a scale of proportionate extent. We
shall extend it still farther by contrasting in the
same manner the two other classes of the Ver-
tebrata, Reptiles and Fishes.

I. The organs which prepare the materials

of the blood — the digestive apparatus is more
complete among Reptiles than among Fishes;
1st, in the dental apparatus when it exists;
2d, in the more distinct stomach; 3d, in the
greater length of the intestines.

II. The blood of Reptiles is superior to that
of Fishes both as regards the nature of the
globules and their relative proportion, their size
being smaller, and their numbers greater, than
among Fishes.

If the whole of the blood in the Reptile is
not transmitted through the organ of respira-
tion, whilst in the Fish it is, a larger quantity
of this fluid is brought into contact with the air
in the same space of time in consequence of
the greater extent of surface of the organ in the
Reptile, and then the Reptile has the farther
immense advantage of a pulmonary or aerial
respiration, whilst that of the Fish is branchial
or aquatic. To conclude, the nervous system
of Reptiles is much more developed in the
cerebro-spinal axis, and especially in the ence-
phalic extremity, than in Fishes.

From this comparison it follows that the
organic and functional conditions, judging of
these in conformity with the principles which
we have taken as our guide, are much more
favourable to the development of heat in Rep-
tiles than in Fishes. This theoretical deduction
is fully confirmed by direct observation, as we
have seen above, and this verification becomes
a new confirmation of the accuracy of the prin-
ciple.

We continue to pursue this parallel by a
summary comparison of the organization in its
relations with the production of heat in the
cold-blooded Vertebrata and the Invertebrata
generally. A glance suffices to shew the vast
inferiority of the Invertebrata in this as in every
other respect. In the first place their blood is
so little of the same nature as that which has
been recognized most favourable to the produc-
tion of heat, that it wants the characters whe-
ther of arterial or of venous blood. The blood
of the Invertebrata, with the exception of a
very small group (the worms with red blood),
is colourless. In the structure and number of
its globules it is also greatly inferior. The
globules, indeed, may be smaller, but then they
are of a much more simple structure, and con-
sequently lower in the scale, in other words
more imperfect. In the relation to the fluid
part of the blood too, they are in much smaller
proportion than among the Vertebrata. An
analogous character is manifest in the tissues
generally, the proportion of water in them
being incomparably larger in the Inverte-
brate than in the Vertebrate series of animals.
Finally, there is an immeasurable inferiority in
the nervous systems of the Invertebrate com-
pared with even the lowest of the Vertebrate
series of animals.

Fiom all this it results, agreeably to the
principle of which we are now showing the
application, that the Invertebrate ought to have
a much smaller capacity of producing caloric
than even the cold-blooded Vertebrate animals;
and this is exactly as we found matters to be
by direct experiment in regard to the tempera-

654

ANIMAL HEAT.

ture of the different classes, the results of which
have been already stated. The comparison
might be carried out in regard to Insects and
the Mollusca, which present some appreciable
differences. If attention were confined solely
to the structure of the greater number of the
organs of nutrition, which are much more
largely developed in Molluscs, it might be
inferred that they had a higher calorific power
than Insects; but when we take into the account,
1st, the final result of the nutritive functions,
the quality of the tissues, which in the Mollusc
are much more loaded with watery fluid, by
which they acquire a greater degree of softness
and flaccidity, (whence the class has its name,)
whilst in the Insect they are, on the contrary,
as remarkably dry and firm ; — 2d, when the
most general mode of respiration is compared
in the two divisions, it being in the Insect
aerial, in the Mollusc aquatic ; 3d and lastly,
when we glance on the one hand and on the
other at the state of the nervous system, and
observe how much less perfectly this is developed
in most of the Molluscs than in the Insect, it is
impossible not to perceive that according to the
principles influencing the production of heat,
the Mollusca must be inferior in this respect
to Insects. This is indeed the result of obser-
vations of all kinds, however imperfect or
limited these may have been, as we have seen
above.

It is impossible to carry the comparison
further; the phenomena connected with heat
in the lower grades of the animal creation
become inappreciable ; and this even in virtue
of the same principle that has been an-
nounced ; for the tissues are found to become
more and more watery as we descend in the
scale, till at length the solid constituent is
almost inappreciable. Of course the circulating
fluid must be watery in a still greater ratio; it
contains but few globules; and then the ner-
vous system falls off in a still greater propor-
tion ; it becomes more and more imperfect, till
at length no trace of it is to be discovered.
We thus arrive at the last links of the chain,
after having run over the whole animal king-
dom, and we have found one uniform principle
of correspondence between organic modification
and calorific power. It were difficult to imagine
any more satisfactory proof of a principle than
has been afforded ; indeed as this has on no
one occasion been found belied, we are fully
authorized to regard it as established.

We hare as yet examined but two points in
reference to animal heat; 1st, the temperature
of man and of the different classes of animals;
2d, the general relations of organization with
the production of heat. In mentioning the
temperature in any case, we have spoken
of it as determinate ; and farther, to have data
that should be always comparable, the tempe-
ratures have been taken regularly in the same
places, — viz. the mouth in man, and the other
extremity of the intestinal canal in animals.
We have still to ascertain whether the tempera-
ture varies or is identical in different parts of
the body.

Temperature of different parts of the body.

— There is no need of the thermometer to tell
us that all parts of the body do not at all times
preserve the same temperature. We are
often certain that the extremities are colder
than the trunk for example; and a law of
decrease of temperature in the ratio of the dis-
tance of parts from the heart had even been
deduced from this observation. But when
exact measurements came to be taken, this law
was soon found to be at fault, as will be seen
by-and-by in the course of these observations.
Dr. Davy, in taking the temperature of the
different parts of the body of a lamb, found
that of the right ventricle of the heart 40°, 5
(105° F.), that of the left ventricle 41°, 1 (106°
F.). The left ventricle was therefore higher in
temperature than the right to the extent of a
degree of the scale of Fahrenheit's thermometer.
The temperature of the rectum corresponded
with that of the right ventricle.

In my inquiries along with M. Gentil
into the relations in point of temperature of
certain external parts, we found in a strong
man, perfectly at rest in mind and body,
in the month of July, the external air being at
21°, 25 c. (71° F.), the temperature of the
mouth 38°, 75 (102° F.) ; that of the rectum
corresponded. The hands presented the next
highest degree, marking nearly 37°, 5 (99°, 5 F.).
What is remarkable is that the axillse and
groins, which corresponded with one another,
were very sensibly lower in temperature than
the hands ; they did not raise the thermometer
higher than 36°, 96 c. (99° F.). The cheeks
marked 35°, 93 (96°, 5 F.), the temperature
being ascertained by enveloping the bulb
of the thermometer in the skin of these
parts. The feet were a little lower, 35° 62
(about 96° F.) ; their temperature being deter-
mined by placing the thermometer between the
two, so that the bulb was surrounded on every
side. The temperature of the feet was, there-
fore, notably lower than that of the hands,
differing to the extent of 1°, 88 of the centigrade
scale (above 3° of Fahrenheit's thermometer).
Placed on the skin between the thorax and
abdomen the thermometer was at its minimum,
not rising higher there than 35° (95° F.) ; but
here a part of the bulb being in contact with
the air, there must have been considerable
cooling.

As the question here is not of absolute but
merely of relative temperatures, we can make
great use of the results come to by the different
writers quoted. We shall present a summary
of these under the following head.

Relations between the temperature of inter-
nal parts. — 1st. The warmest part of the body,
according to John Hunter, is in the abdomen
close to the diaphragm. 2d. The next part in
point of temperature is the left ventricle of the
heart. 3d. The right ventricle of the heart is
the next in succession. The rectum and the
mouth shut are of the same temperature. The
greatest difference consequently between the
temperature of these internal parts does not
amount to more than 1° centigrade, or at the
utmost 2° Fahrenheit.

Supposing the relations in temperature of the

ANIMAL HEAT.

655

internal parts to be pretty constant in the
normal state, the temperature of the right ven-
tricle of the heart and of the rectum may be
determined by taking the temperature of the
closed mouth ; that of the left ventricle will be
found by adding 0,44 c., or 1° F., to the degree
indicated.

Relations in point of temperature between
external parts. — We have only data for insti-
tuting comparisons in regard to the hand,
the axilla, the groin, and the feet among the
external parts of the body. In a moderate
summer-heat the hand appears to be the part
which is most susceptible of showing a high,
the feet the parts most susceptible of exhibiting
a low temperature. The axilla and groin gene-
rally exhibit nearly the same degree of tempe-
rature; and the amount in which they differ in
this particular from the mouth may be stated at
about 1°, 75.

When we direct our inquiries with a view to
ascertaining any general relation in the tempe-
ratures of different parts of the body, whether
external or internal, we soon discover, as has
been already stated, that this has no connexion
of an inverse kind with their distance from the
heart. At the same time there is a general
condition discovered influencing the tempera-
ture of the different parts. This is their situa-
tion in reference to the surface or inside of the
body. The temperature is higher, for instance,
within the trunk than on its outside. What-
ever other reason may be assigned for this,
there is one which is purely physical, that must
influence it powerfully. It is obvious that the
surface of the body and limbs must cool much
more rapidly than the interior of the body. So
that, supposing the temperature at first to be
every where uniform, the difference in the rate
of cooling would very soon suffice to cause a
notable reduction on the exterior beyond that
which took place in the interior of the body.
This cause, however, can only be charged with
its own share of influence ; there are others
which must act with considerable effect, and
among these especially the one upon which the
production of heat depends. We have seen
that the condition of the functions of nutrition
most closely in relation with animal heat was
connected with the arterial blood. Now inas-
much as the arterial blood is that which is most
intimately connected with the production of
caloric among animals, we might fairly expect
that the temperature generally would be rather
above that of the venous blood. And we have
seen that there was actually a difference be-
tween the temperatures of the two ventricles,
that of the left being the higher. Experiment
has also shown that there was a corresponding
difference in the temperatures of the two kinds
of blood circulating in the arteries and veins ;
arterial blood is actually higher in temperature
than venous blood to the extent of a degree of
Fahrenheit's scale. We shall add here, and in
conformity with the same principle, that it is
to this difference of temperature of the two
kinds of blood that the difference in the tempe-
rature of the right and left ventricle of the heart
is owing. We need not be hindered in adopt-

ing this conclusion from the circumstance of
the blood of either ventricle being found in a
slight degree inferior in temperature to the ven-
tricle itself, inasmuch as the blood abstracted
from the canals that contain it, and exposed to
the air, begins to evaporate, and loses heat ra-
pidly. Nevertheless it is not demonstrated
that the difference in temperature of the blood
out of and of the blood in the ventricles of the
heart depends on this cause. There may be
another at work; the influence of muscular
contraction for instance, a point which we shall
examine generally by-and-bye. New means of
estimating variations of temperature have been
lately discovered, by which changes that en-
tirely escaped us as judged of by the thermo-
meter are made abundantly obvious; by which,
indeed, the temperature of parts inaccessible in
their natural and normal condition to the ther-
mometer are now investigated without diffi-
culty. In using the thermometer as the means
of estimating temperature, it is evident that
this instrument could not be introduced into
the external parts without injuring the tissues,
without incisions, &c., which would necessarily
alter them materially, and produce so much dis-
turbance in their functions, that an increase or
diminution of temperature must almost neces-
sarily have been the consequence. The ther-
mometer, besides, however small its dimen-
sions, has the inconvenience of always either
absorbing or giving out a considerable quantity
of heat according to circumstances, before it
gets into equilibrium with the parts with which
it is brought into contact. A necessary fall or
rise in the absolute temperature of these parts
is the natural consequence of this. Further,
the thermometer is incapable of showing sudden
variations in temperature; several minutes must
always elapse before it gets into a state of equi-
librium in regard to temperature with the parts
or medium surrounding it. If a thermometer,
for instance, be placed in the mouth, three or
four minutes must elapse before it will cease to
show any increase of temperature. Now if any
calorific phenomena of short duration were de-
veloped in that time, it is evident that all idea
of their occurrence would escape us.

These considerations led to the adoption of
thermo-electrical means by Messrs. Becquerel
and Breschet. The processes they employed
in procuring indications of temperature were
the following. The only means we have of pe-
netrating into the interior of organs without in-
jury is to make use of a needle similar to that
employed in acupuncture. Now it is easy to
arrange this needle so as to obtain thermo-elec-
tric indications, which proclaim immediately
and with the greatest precision the temperature
of the part or medium with which the point
happens to be in contact. It is enough to
compose this needle of two others in metal,
two of the extremities of which are soldered
together in a few points only, whilst the other
two are placed in communication with one of
the extremities of the wire of an excellent ther-
mo-electric multiplier. The slightest changes
of temperature at the points of junction give
origin to an electrical current, which, in reacting

656

ANIMAL HEAT.

on the magnetic needle, causes it to deviate by
a certain number of degrees, which conse-
quently become indices of the temperature of
the point of the needle, and therefore of the
medium in which it is placed. The multiplier
ought to be so sensitive as to show a deviation
of one degree of the magnetic needle for each
one-tenth of a degree of temperature as mea-
sured by the centigrade scale, an amount of
temperature made sensible by the union of the
two ends of the wire which forms its circuit
with an iron wire soldered by its ends.

So much for the general principle upon
which and by which the inquiries of Messrs.
Becquerel arid Breschet were conducted. As
to all the precautions necessary to render re-
searches of the kind fruitful, as these are nume-
rous, we beg to refer for an account of them to
the memoir of the authors themselves.

Difference of temperature according to the
depth. — By the means contrived by Becquerel
and Breschet the temperature of the calf of the
leg at the depth of four centimetres from the
surface was found to be 36°,75 (about 98° F.),
and at one centimetre 34°,50 (about 94° F.),
a difference of 2°,25 (4° F.). In the chest the
temperature at the depth of the pectoralis
major, compared with that of the superficial
cellular tissue at the depth of one centimetre,
showed a corresponding difference; the deeper
parts were 2°,25 (about 4° F.) higher than the
tnore superficial. In seven experiments made
on the arm the mean difference of temperature
between the deeper strata of the biceps and the
superficial cellular tissue over the same muscle
amounted to 1°,59 c. in favour of the deeper
parts.

The next point of inquiry was to know whether
it was enough to penetrate to the depth of three
or four centimetres into the trunk and limbs to
attain the points of highest temperature in
these parts. With this view we have compared
the observations made by the authors mention-
ed, in the same individual, with regard to the
temperature of the mouth and of the biceps
muscle, and we find that the mean temperature
of the mouth was 36°,89, that of the biceps
36°,88, (about 98° F.),— a result which may be
called identical with the former. The mean of
seven other experiments, however, shows the
relation of 36°,89 c. for the rnouth, of 36°, 75 c.
for the biceps ; the difference here is evidently
in favour of the mouth. It were to be wished
that inquiries in this direction were multiplied
in order that absolute certainty may yet be
attained.

In the preceding experiments, in penetrating
to different depths, the nature of the tissues at-
tained also differs, a circumstance which must
tend to complicate the results ; for it is possi-
ble that the nature of the tissue may have some
influence on the evolution of heat. This is
even an inference which we should deduce
from the principles already established, were it
merely in consideration of the different quanti-
ties of blood they contain. And this conclu-
sion is even confirmed by the experiments of
the parties mentioned ; for on compressing the
humeral artery strongly, the motion of the nee-

dle immediately announced a fall of tempera-
ture to the extent of several tenths of a degree.
This experiment is interesting from the rapidity
and precision of the effect. There are other
cases well known by which we are led to a
corresponding conclusion ; but nowhere else is
the fact seen in so simple a guise, or in so ma-
nifest a relation of cause and effect. In opera-
tions for aneurism, indeed, and other cases re-
quiring the ligature of a large artery, the tem-
perature of the parts supplied by the vessel
tied falls so low as to require to be supported
by artificial warmth ; but then a severe and
bloody operation has been performed by which
the conditions are complicated. In the expe-
riment mentioned, on the contrary, nothing
occurs to disturb the state of the economy ; the
effect instantly follows the cause, and its
amount is even at the same moment ascer-
tained.

Seeing, then, that in the same tissue the freer
or more interrupted access of arterial blood
causes the temperature to vary, it is fair to infer
that the relative freedom of access or quantity
of this fluid which circulates through other
tissues should have an influence upon their
temperature ; in other words, that tissues differ
in their power of producing heat according to
the quantity of blood which circulates through
them. We can scarcely doubt, therefore, but
that the differences of temperature observed be-
tween the deeper and more superficial parts are
complicated by the mere fact of difference of
distance from the surface, and also by the cir-
cumstance of difference of tissue. The super-
ficial layer in the preceding experiments was
cellular membrane ; the deeper layer was mus-
cular. But the muscles receive a much larger
quantity of blood than the cellular membrane,
and their temperature, from this circumstance
alone, ought to be higher.*

* [Messrs. Becquerel and Breschet, in a memoir
lately read before the Royal Academy of Sciences,
(Ann. des Sciences Nat. Mai 1838.) entitled,
" Further Observations on the Temperature of the
Tissues of the body of Man and the lower Animals,
as ascertained by means of thermo-electric effects,"
have made a few additional observations which de-
serve quotation in this place. The temperature of
the mouth being used as the standard of compari-
son, the temperature of the biceps muscle was
found to be but 36°, 20 c., instead of 36°, 60,
which was the term derived from previous experi-
ments, and to fall short of the temperature of the
mouth by as many as 4° c. (above 7° F.)

In making experiments upon the influence of
the temperature of surrounding media upon that of
the tissues, Messrs. Becquerel and Breschet intro-
duced the needles of their thermo-electrical appara-
tus into the biceps muscles of two young and
healthy individuals, the air at the time marking
16° c. (61°F. ). The magnetic needle did not deviate
in the least ; so that the two muscles possessed
precisely the same temperature. One of the arms
was now immersed for a quarter of an hour in water
of the temperature successively of 10°, 8°, 6Q, and
0Q c. (50°, 47°, 43°, and 32° F.). The deviation of
the needle did not amount to more than two degrees
of its scale in favour of the muscle of the arm which
was not plunged into the water. The partial cold
bath, consequently, had only caused a depression
of temperature to the extent of about one-fifth of a
degree c. The arm being now plunged into water

ANIMAL HEAT.

657

We might even deduce from this a fact of
great importance in the animal economy, viz.
that muscular contraction is a cause of heat, in-
asmuch as it determines the afflux of blood to-
wards the muscles themselves as well as to-
wards all the surrounding parts. It is very
difficult to conceive an occasion of verifying
this position in its simplicity ; for bodily efforts,
in which the skin becomes red and injected,
are always accompanied with some disturbance
of the respiration and motion of the blood. We
have, however, had an opportunity of seeing
one individual of athletic powers, who, by
merely throwing the muscles of the fore-arm
into strong contraction, could cause the integu-
ments of the forearm to become red. During
the act of muscular contraction consequently,
the temperature must have a tendency to rise.

at the temperature of 42° c. (108° F.) for fifteen
minutes, the temperature of the muscle as compared
with that of the other was found to have increased one-
fifth of a degree. When the whole body was plunged
iu a hot bath at the temperature of 49° c. (120P F ),
the deviation of the needle varied from 12° to 13°
and 14° of its scale, which indicated a rise in tem-
perature of from one- fifth to two-fifths of a degree c.
The pulse was increased to 112 beats per minute,
the body being immersed in this bath. The tempe-
rature of the body before immersion was 36°, 70 c.
(98° F.), a degree to which it immediately returned
after coming out of the bath. In trying experi-
ments of the same kind subsequently, but with
baths at a somewhat lower temperature, namely,
42°, 50 (109° F.), no rise of temperature was indi-
cated. The immersion in these cases was not con-
tinued for more than twenty minutes. Had it been
protracted for a longer time, the result might have
been different. When a doe, whose muscles indi-
cated a temperature of 38°, 50 (102° F.), was
plunged into a hot bath at 49° c. (120° F.), the
temperature rose rapidly by half a degree, a degree,
and finally two degrees c. ; but the animal had be-
come so much enraged that it was found necessary
to take him out of the water. The needle of the
apparatus being passed into the chest, a like rise in
temperature was indicated ; but ihe rise in tempe-
rature was found to happen principally when the
animal became angry ; and it is doubtful how far
the state of exasperation influenced the results.

In one experiment the one needle being passed
into the biceps muscle of a young man, the other
into the long radial supinator of a man aged forty-
five, no sensible deviation of the magnetic indicator
ensued. A vein was then opened in one of the
arms, as near as possible to the point at which the
needle had been introduced, but no change of tem-
perature took place either during or after the flow
of the blood. The common iliac artery of a dog
was now isolated and a ligature thrown loosely
round it, so that it could be compressed or left free
at pleasure, and one of the needles of the apparatus
plunged into the fleshy part of the thigh. The
current of blood having been interrupted, the tem-
perature of the limb began to fall, but not until
after the lapse of an interval of twenty minutes,
when it still amounted to no more than about half a
degree c. The free access of blood having been
restored, the temperature soon rose again to the
normal point. The effect, though trifling in this
case, — and the same experiment was repeated several
times always with the same result, —is still suffi-
cient to show that the arterial blood exerts a direct
influence upon the temperature of the animal tis-
sues. The effect, however, it is obvious from the
time which elapses before it becomes apparent, is
to be attributed, not to the blood which is circulating
in the trunks and branches of the vessels, but to
that which is contained in the vascular rete. — ED.]
VOL. II.

This fact is demonstrated in the most satis-
factory manner by the delicate experiments of
Messrs. Becquerel and Breschet as follows.
When one of the joinings (soudures) is kept
uniformly at a temperature of 36° c. (97° F.).
and the other is inserted into the biceps muscle
with the arm extended, the magnetic needle
was found to deviate about .10 of a degree.
On the arm being bent, however, the amount
of deviation was observed to increase suddenly
to the extent of from one to two degrees.
Waiting till the oscillation of the needle and
its return are completed, if the arm be bent
anew so as to give a fresh impulse to the needle
for several times in succession, a deviation of
fifteen degrees is obtained at length, equivalent
to a difference of five degrees in comparison
with the original deviation, and corresponding
to an increase of about half a degree of tem-
perature as measured by the centigrade scale.
If the needle be inserted into the biceps, and
the arm be used in the action of sawing for
about five minutes, the temperature is observed
to rise considerably, sometimes to the amount
of a degree centigrade.

In these researches, then, we have evidence of
facts of which we could not have acquired any
precise information by our ordinary means of
investigation. Every one, indeed, knows that
exercise warms the body ; but every one also
sees that in producing this effect, besides the
contraction of the voluntary muscles, exercise
is accompanied by an acceleration in the mo-
tions of the heart and organs of respiration.
In this simultaneous concurrence of a variety
of phenomena, it was impossible to distin-
guish the share which each had in the general
result. Such an analysis could only be made
by an experiment of the delicate and ingenious
description of that which has been detailed.

It would appear that it is by the repetition
of the muscular contraction after each relaxa-
tion that the highest evolution of heat is ob-
tained, each contraction producing a slight in-
crease of temperature, which, with the addition
of that which follows, mounts to a certain
limited point which it cannot pass. Let us
remark, however, that the mere persistence of a
primary contraction ought to have the effect of
causing or maintaining a temperature higher
than that which is evolved by a contraction
followed immediately by relaxation ; indeed it
is now known that a permanent muscular con-
traction is but a series and succession of smaller
and imperceptible contractions, following each
other with extreme rapidity.

It were well to observe here, that neighbour-
ing parts must increase in temperature at the
same time much less in consequence of the
direct communication of heat in virtue of con-
tiguity than by the afflux of blood, which,
transmitted to the muscles in larger quantity,
must also be more copiously than usual dis-
tributed to adjacent tissues. The relaxation of
the muscles ought, on the other hand, to have
a tendency to reduce the temperature, and this
by so much the more as the relaxation is more
complete. From all this it follows that the
attitude and state of the bodv will be favoura-

2 x

658

ANIMAL HEAT.

ble to cooling in the ratio of the general relax-
ation of the muscles, and of the degree in which
each of them in particular is in a state of qui-
escence. This is what happens in sleep, of
which we shall speak by-and-bye.

In the rise of temperature observed along
•with muscular contraction, we have in the first
place only considered the action of the blood ;
but neither contraction of the muscles nor the
afflux of a larger quantity of blood could take
place without the nervous influence ; for it is
the will which determines the muscular contrac-
tion, and the will only acts through the me-
dium of the nerves which are distributed
to the muscles. From this consideration it
follows equally as from general relations pre-
viously exposed, that whatever lessens the
nervous influence will, likewise tend to reduce
the temperature. Here we are, then, reverting
to the two general conditions which we had
already found to be the most influential in ca-
lorification, namely, the arterial blood and the
nervous system.

This examination of the relative tempera-
tures of the different parts of the body has led
us, by the immediate comparison of the super-
ficial and deeper layers, to the consideration of
the

Influence of external temperature. — An in-
ert or inanimate body of higher temperature
than the surrounding medium will of neces-
sity cool faster at its surface than in its internal
parts. A living body, likewise, having within
itself a permanent source of heat, which we
shall suppose equally distributed through it,
will lose more caloric from its surface than from
its interior. This loss will become apparent
by the cooling of the surface, so long as the
source of heat remains everywhere equal. If,
on the contrary, it be unequally distributed,
if it be greater towards the surface, so
as to compensate the greater loss which
takes place there, the surface will have
the same temperature as the interior. Without
such a supposition it were necessary that the
surface of the body should be lower in tem-
perature than the interior. This, indeed, is the
actual state of the case. The external parts of
living bodies are colder than the internal parts,
because on the one hand the focus of heat is
less, by reason of the nature of the component
tissues, and on the other because the loss of
heat there is greater. When the external tem-
perature falls, then the outer layers will tend to
sink in temperature also, and will, in fact, sink
so long as the internal source of heat remains
the same. This partial refrigeration will be
propagated internally, and the general tem-
perature will be lessened unless the economy
provides against such an occurrence by an in-
crease of activity in its calorific powers.

The same reasoning is applicable to move-
ments of the temperature of bodies under
the influence of that of the air. Heat will be
propagated from without inwards, and will
raise the general temperature of the body, un-
le; s it lessens in the same proportion as it re-
ceives external temperature, that which it pro-
duces of itself.

The consideration of the changes in the in-
tensity of the internal focus, in other words, in
the faculty of producing heat, and of the con-
ditions which determine these, is the most im-
portant point of all in the study of animal
heat, on account of the multitude of practical
applications which result from it.

It is obvious from what has already been
said that there is an essential difference between
inert or inanimate and animate bodies subjected
to the influence of external temperature. The
temperature of the former depends solely oh
the general laws which regulate the propaga-
tion of heat, whilst the temperature of the
others is subjected to the influence of another
element, namely, the heat which they them-
selves produce. Did this element continue
fixed and invariable, it would be possible to
determine, by the application of the known
data of physics, what must be the temperature
of a living body under the influence of a given
external temperature. But if this element
varies, and the laws according to which it
varies are unknown, it becomes impossible to
predict in what manner the temperature of an
animal will be affected by that of the medium in
which it lives. It is only very lately, therefore,
that the temperature of man and warm-blooded
animals, with the exception of those that hy-
bernate, has been believed to continue unaf-
fected in the midst of extensive variations in
the temperature of the surrounding atmosphere.

Variations in the temperature, of animal
bodies in a state of health, independently of
external temperature. — Duly to appreciate the
inquiries that have been instituted in this direc-
tion, the first question to be asked is, whether
or not the temperature of the body presents
variations, although external conditions continue
the same, or nearly the same? The answer
here must be in the affirmative : the body
varies in temperature at different times, exter-
nal circumstances as to temperature continuing
nearly the same. This is apparent in the ob-
servations of Dr. John Davy instituted with
another view, but quite available here. We
perceive that the individual designated No. 1,
having a temperature of 37° 8 (100° F.), when
the air was at 26°, 4 (79° F.), had a tempera-
ture of only 37°, 5 (99°, 75 F.) when the air
was at 26P, 7 (80° F.), that is to say, the same
person showed a third of a degree c. less of
temperature, when the air, instead of becoming
colder, had actually become warmer in the
same proportion. The temperature of No. 3
was 37°, 2 (99° F.), when the air marked 25°,
5 (78° F.), and on another occasion it was only
36°, 9 (98° F.), when the air was 26° (79° F.) ;
in other words, the temperature of the body,
instead of rising, had actually fallen by 0°, 7
cent., when that of the external air had risen
0°, 9 cent.

Influence of the natural temperature of the
air on that of the body. — It must be obvious
from the facts of the last paragraph that the
influence of external temperature cannot be
appreciated without having recourse to means
of observation calculated to make variations
dependent on foreign causes to disappear.

ANIMAL HEAT.

659

To render the comparison of the mean sums
obtained more certain, we shall confine our-
selves to the observations of the inquirer just
quoted, made upon the same individuals at
different temperatures. The following series is
after the data supplied by Dr. Davy : —

Temperature of the air. Mean temperature of Jive

men.
15°, 5 (60° F ) ..... . 36°, 85 (98° F.)

25°, 5 (78° F.) ....... 37°, 16 (99° F.)

26°, 4 (79° F.) ....... 37°, 32 (99° 5, F.)

26°, 7 (80° F.) ....... 37°, 58 (100° F.)

27°, 8 (82° F.) ....... 37°, 70 (100° 5, F.)

It is apparent that these differences, even the
extremes, do not surpass the limits of the
variations which the same individual exhibits,
or may experience spontaneously under the
same temperature of the air. But when it is con-
sidered that these differences are mean results,
forming a series increasing with the rise of the
external temperature, it is impossible to doubt
of their standing in the relation to one another
of cause and effect. If this dependence and
connection actually exists, we must allow that
it is very little obvious at the temperatures
within the limits of which these observations
were made ; for whilst the temperature of the
air varied to the extent of 12°, 3 c., the changes
in the mean temperature of the body did not
exceed 0°, 9. Such slight differences being apt
to leave uncertainty in the mind as to the cause
producing them, we shall confirm the impres-
sion they are nevertheless calculated to make
by citing others, for which we are indebted to
Dr. Reynaud, surgeon of the corvette La
Chevrette, in a voyage of discovery in the
Asiatic seas undertaken in the year 1827. The
instruments used were furnished by the best
makers of Paris, and were compared by M.
Arago with those of the Observatory ; and the
observations were made conjointly with M.
Blosville, lieutenant of the vessel, charged by
the Academy of Sciences of Paris with various
researches in natural philosophy.
Mean temperature of the*^
body deduced from ob- j
servations four times re-
peated upon each of eight

0_
men, under the torrid 37

0.0 . ,
37 > H

T? \

zone, the external tempe-

rature varying from 26°

to 30° c. (79°, 86° F.)J
Mean temperature of the"^

same eight men observed

three times in the tern-

perate zone, the external

temperature varying from

12° to 170(53°to62°F.)J

These results confirm those of Dr. Davy by
so much the more as they were made within
the same limits of external temperature. The
mean rise of the temperature of the body un-
der the influence of that of the air is also
equally confirmed ; but the amount is still less
than as given by the English observer.

It seems impossible, then, to doubt that the
natural variations in the temperature of the air
affect that of the body of man ; but this is
only in a very trifling degree, at least within the

limits of temperature in which any extant ob-
servations have been made. It is greatly to be
regretted that neither of the observers quoted
had opportunities of ascertaining the effects of
much lower temperatures than those they have
given. There are, it is true, many isolated ob-
servations made by voyagers in the Arctic
regions, both upon animals and man, and
although conducted in no regular series, or as
points of comparison with one another,
they still lead to the same general result,
namely, that great differences in the tempera-
ture of the air cause slight differences in the
temperature of the body of animals. Thus, in
the voyage of Captain Parry it was observed
that the temperature of the Mammalia was very
high. With the external thermometer at
— 29°, 4 ( — 21°, F.), the temperature of the
white hare was + 38°, 3 (101° F.). With the
thermometer at — 32°, 8 (27° F.), the tempe-
rature of a wolf was + 40°, 5 (105 F.); the
temperature of the Arctic fox, under nearly the
same circumstances, namely, when the thermo-
meter was standing at — 35° ( — 31° F.), was
as high as -f- 41° 5 (107° F.). Similar obser-
vations have since been made in the same high
latitudes upon man.

The variations in the temperature of warm-
blooded animals according to that of the seasons
has been studied by the present writer, who con-
firms the results just stated. The experiments
of the writer were made upon a great num-
ber of sparrows recently taken at different
seasons of the year, which is preferable to
keeping these creatures in captivity for any
length of time. The mean temperature of
these birds rose progressively from the depth
of winter to the height of summer, within the
limits of from two to three degrees centigrade.
The observations made on sparrows exhibited
the greatest differences. In the month of Feb-
ruary the mean temperature of these birds was
found to be 40°, 8 (105° F.) ; in April 42°
(108° F.), in July 43°, 77 (111° F.). The
temperature from this time began to decline,
and followed, in the same ratio in which it had
increased, the sinking temperature of the year.

Influence of media upon temperature. — The
media in which animals live do not act solely
in the ratio of their temperature, but also by
virtue of the intensity of their cooling or heating
power. Thus air and water at the same
degree of heat will have a very different influ-
ence on the temperature of the bodies plunged
in them. The power of air in heating or
cooling is commonly known to be very inferior
to that of water. Bodies acquire or lose tem-
perature much more slowly in air than In water.
A water-bath according to its temperature com-
municates sensations of heat or cold far more
rapidly and powerfully than an air-bath.
The writer and M. Gentil made the following
experiment: — A young man seventeen years of
age, of strong constitution and in good health,
after remaining for twenty minutes in a bath
the water of which marked 13° R. (61°, 5 F.),
whilst the air was 14°, R. (63° F.), half an
hour afterwards was found to have lost half a
degree of his original heat in the mouth and

2x2

660

ANIMAL HEAT.

hands, and a degree and a half in the feet. This
temperature of the air may be regarded as a
mean, or intermediate between heat and cold,
and may be termed temperate (61° to 62° F.).
It was superior to that of the water by a degree
R., and yet the water of the bath, after immersion
in it for no longer a time than twenty minutes,
had reduced the temperature of the body
according to its parts from half a degree to a
degree and a half R.

Effects of external temperature upon an
isolated part of the body. — Under this head
let us examine, 1st, the extent of the effect, and
2nd, its influence on other parts. The facts
we shall borrow from the researches just
quoted, those namely of myself and M.
Gentil. The hand, at 29° R. (98° F.) having
been kept immersed in a tub of water cooled
down to + 4° R. (41°F.), in all during twenty
minutes, five minutes after it had been taken
out of the water, marked no higher a tempera-
ture than 10° R. (55° F.) This experiment
shows how rapid and extensive, and how much
beyond what could have been anticipated, may
be the refrigerating effects of cold water applied
to an extremity. Another not less remarkable
result is the singular slowness with which the
temperature of an extremity is regained,
although exposed to the gentle warmth of the
air. The hand in the above experiment, after
the lapse of twenty-five minutes from the time
it was removed from the water, was still no
higher than 16*° R. (69° F.), and after the
expiration of an hour and a half it was only
24£° R. (87° F.). The foot, in the same cir-
cumstance?, gave nearly analogous results.

In a number of experiments of the same
nature as the last, where one hand was plunged
in water cooled down by ice, the other hand,
which was not subjected to the actionof the cold
bath, lost nearly 5° R. in temperature.

It is therefore apparent, 1st, that partial
chills, or the exposure of individual parts to
low temperatures, may be and are felt very
extensively even when the cold is not very
severe ; 2nd, that the chilling of a single part,
such as the hand or the foot, may cause a loss of
temperature in all the other parts of the body,
even far beyond what could have been pre-
sumed as likely or possible. These facts give
a key to the right understanding of the immense
influence which partial chills are capable of
exercising on the state of the general health

Of the effects of partial heating. — The hand
being immersed in water heated to the tem-
perature of 34° R. (109° F.),rose one degree of
the same scale, and the temperature of other
remote parts not immediately exposed to the
influence of heat were found to have risen in a
corresponding degree. Whence follows this
axiom, — that we cannot either raise or lower
the temperature of any one part of the body
without all the other parts of the frame being
affected, and suffering a corresponding rise or
Jail in temperature, more or less according
to circumstances. We may further presume
from the comparison of these facts, that the
body and its parts are liable to variations of
temperature towards either extremity of the

scale from the mean, much more considerable
than are generally imagined. This latter fact
will appear very evidently from the other
inquiries which are now to engage our atten-
tion.

Effects of an excessively high or excessively
low external temperature upon the temperature
of the body. — Hitherto we have only considered
the changes in the temperature of the body pro-
duced by moderate degrees of external heat and
cold. We now pass on to the examination of
the effects caused by extreme external tempera-
tures, and first of those that follow from
excessive heat; designating by excessive heat
any temperature that surpasses that of the
human body. On a summer's day, the
temperature of the air being 37°, 77 c.
(100° F.), Franklin observed that the tempera-
ture of his own body was nearly 35°, 55 c.
(96° F.). This fact, which is perhaps the first
of the kind noted, is highly deserving of atten-
tion. It proves that man, and by analogy
other animals, have a power of keeping their tem-
perature inferior to that of the air. As in the ob-
servation quoted there is no means of knowing
what effect the excessive external temperature
had produced upon the temperature of the
observer, recourse must be had to other facts.
In numerous experiments made in England by
Dr. Fordyce and his friends, and subsequently
by Dr. Dobson, in which these experimenters
exposed themselves to very high temperatures,
which on some occasions exceeded that of
boiling water, the heat of the body was never
observed to rise more than one, two, three, or
four degrees of Fahrenheit's scale at the utmost.
As in these experiments the object especially
proposed was to determine the degree of
external temperature which the body could
bear, all the attention which would have been
desirable was not given to determine the tem-
perature of the "body before, during, and
after the experiments. This is an omission
which is common to the experiments of For-
dyce and Dobson. The highest temperature of
the body noted by Dr. Dobson is 102° F., but
he does not mention the heat before the experi-
ment, nor does he notice the rate of cooling
subsequent to its termination. The highest
temperatures of the human body exposed to
excessive heats ever observed, were remarked
by Messrs. Delaroche and Berger in their own
persons. The temperature of M. Delaroche
being 56° 56 c. (98° F.) increased 5° of the
centigrade scale, by remaining exposed in a
chamber the temperature of which was 80° c.
(176° F.). M. Berger, whose temperature was
the same as that of M. Delaroche, gained
4° c. by remaining for sixteen minutes in the
hot chamber at 87° c. (188°, 5 F.). These
experiments are liable to this objection, — that
the temperature was taken in the mouth in an
atmosphere of much higher temperature, which
might have some influence in raising the ther-
mometer. To arrive at conclusions against
which no kind of objection could be raised,
Messrs. Delaroche and Berger exposed them-
selves in succession in a box, out of which they
could pass their head ; the hot air or vapour of

ANIMAL HEAT.

661

the interior being prevented from escaping by
means of a circular pad of soft napkins placed
between the edge of the outlet and the neck.
The temperature of the mouth, in this^way, if it
was increased, must be increased in consequence
of a rise of temperature in the parts of the body
included in the bath . After a stay of seventeen
minutes in the bath, heated from 37°, 5 to
48°, 75 c. (99° to 120° F.), the temperature of
M. Delaroche's mouth rose 3°, 12 c. Under
similar circumstances, the temperature of the
bath being from 40° to 41°, 25 c. (104° to
106° F.), the temperature of M. Berger's mouth
increased 1°. 7 c. in the course of fifteen
minutes.

It is pretty obvious that experiments upon
the human subject cannot be pushed far enough
to ascertain the highest amount of temperature
that can be acquired under the influence of
exposure to air of excessively high tempera-
ture. To judge of this analogically, recourse
must be had to warm-blooded animals of the
two classes, Mammalia and Birds. Messrs.
Delaroche and Berger consequently exposed
different species of Mammalia and Birds to dry
hot air of different temperatures, from 50° to
93°, 75 c. (122° to 201° F.), leaving them im-
mersed till they died. The whole of the ani-
mals that were made subjects of experiment,
in spite of diversity of class and species, and
of the varieties of temperature to which they
were exposed, had gained an increase of tem-
perature nearly equal at the moment of their
death. The limits of the variations being be-
tween the terms 6°, 25 and 7°, 18 c., the amount
of difference did not exceed 0°, 93 c. which is a
very trifling quantity . It may therefore be inferred
that man and the warm-blooded animals cannot,
under the influence of exposure to dry air of
excessively high temperature, have the heat of
their body raised during life to a greater extent
than from 7° to 8° c. The temperature of the
body being increased to this extent becomes
fataf. It is in fact only attained at the moment
of dissolution ; perhaps death has virtually
taken place before it is attained.

We have seen that Franklin observed the
temperature of his body to be lower than that
of the air on a very hot day. Such a circum-
stance is rare in what may be called natural con-
ditions as regards man and the warm-blooded
animals ; inasmuch as it rarely happens that
the temperature of the air surpasses that of
their bodies generally. The case is different,
however, as regards the cold-blooded tribes.
It is not at all necessary that the temperature
of the air be very high to afford opportunities
of observing the phenomenon in question
among cold-blooded animals. This was ob-
served for the first time by Sir Charles Blagden
in a frog, which on a summer's day, when the
heat was by no means excessive, he observed to
be lower in temperature than the surrounding
air. A fact of this kind could not remain
isolated and unconnected with others. Accord-
ingly we observe among the experiments of
Dr. Davy such facts as the following : — The
temperature of the atmosphere being 32° c.
(90° F.), that of a tortoise was only 29°, 4

(85° F.). The air marking 26°, 7 (80° F.),
a frog indicated 25° (77° F.). The air being at
28°, 3 (83° F.), the blatta orientalis was at
23°, 9 (75° F.). The air at 26°, 19 c.,
(79°, 5 F.), a scorpion was at 25°, 3 (78° F.).
It is therefore apparent that the phenomenon is
general among animals with cold blood ; that
during the highest heats of summer, the tem-
perature still falling short of excessive, the heat
of their bodies is below that of the air. There
is thus a limit of summer temperature which
separates two orders of phenomena relative
to the temperature of cold-blooded animals.
Starting from a mean temperature of the air,
that of cold-blooded animals, the vertebrate
as well as the invertebrate tribes, is superior to
this mean, only varying in this respect within
the narrow limits of from a few fractional parts
of a degree to about four degrees centigrade,
until the air attains the summer heat. Towards
this limit the differences decrease, and the
term 25° or 26° c. (77° to 79° F.) attained, they
become nil. The inverse phenomenon is also
observed : the temperature of the greater num-
ber is inferior to that of the air, and the dif-
ferences go on increasing with the rise in
temperature of the external air.

These phenomena are of great interest in
themselves, but of still greater from the light
they cast on questions of a similar kind relative
to man and the warm-blooded tribes of crea-
tion. The slight evolution of heat by the cold-
blooded animals rendering their condition more
simple, allows us to appreciate distinctly the
influence of external causes.

We now proceed to treat of a third condition
influencing temperature, namely,

Evaporation. — :The fluids so far surpass the
solids in the bodies of animals that they cer-
tainly constitute the larger portion of their
masses ; and, further, the exterior surface of
animal bodies generally is extremely porous.
Animals are consequently subjected to the
ordinary physical laws of evaporation. It is
very long since, in addition to the sweat or
visible perspiration, the existence of an invisible
perspiration has been recognized. The latter is
owing in great part to the effects of evaporation.
Now evaporation cannot take place without the
occurrence of cooling or loss of temperature
in the ratio of the quantity of vapour formed.
Without keeping this cause of refrigeration in
view, we should fall into serious mistakes in
estimating the heat of animals. If, for ex-
ample, we would compare the heat of two
animals, which, unwittingly to the observer,
should be under different conditions of eva-
poration, we should deceive ourselves greatly
in regard to their respective temperatures.

It is even so with reference to another fact
bearing upon temperature, which is often forced
on the attention, and which has almost always
led inquirers into error. There are many ani-
mals among the inferior classes of the Inverte-
brata, which tried by the thermometer exhibit
no difference in temperature from that of the
surrounding air. These creatures do not, con-
sequently, appear to have any faculty of pro-
ducing heat. But in the mere fact of their main-

662

ANIMAL HEAT.

taining the temperature of the air about them,
an inherent capacity to produce heat is apparent.
Did they evolve no caloric, they would fall
below the temperature of the air, in conse-
quence of the evaporation which goes on from
the surface of their bodies. They must of
necessity produce as much as is necessary to
repair the loss which takes place from this
cause.

What we have said of animals is equally
applicable to vegetables. To explain the pro-
gression of the temperature of cold-blooded
animals, which we have exposed above, regard
must be had to the relation which connects the
quantity of vapour formed with the degree of
external temperature. Within moderate limits,
which may be styled temperate, the vapour
formed will be nearly as the degrees of tem-
perature of the air. But under higher tempera-
tures, evaporation will go on in a greater ratio
than that of the external temperature. Thus
when the air is cool or moderately warm, eva-
poration is trifling, and among the superior
classes of cold-blooded animals lieat enough is
produced to maintain their temperature above
that of the air. But when the air becomes
warmer, as in the height of summer, evapora-
tion and the cold which results from it increase
in a far greater ratio than the temperature of
the body, so that the body remains at a tem-
perature inferior to that of the air, and this
by so much the more as the external tempera-
ture rises higher. Twenty-five degrees is the
limit at which this change commences in regard
to cold-blooded animals. But it is obvious
that a higher degree must be necessary to ob-
serve such phenomena in man and the warm-
blooded tribes, inasmuch as the heat from
without is for a long time added to that pro-
duced internally, and which among the warm-
blooded tribes is so much greater in amount
than it is among the cold-blooded.

Relations of the bulk of the body with
animal heat. — If the temperature of the larger
animals be compared with that of the smaller,
it will be found that the former do not mark
so high a degree as the latter. In the elephant
and horse, for instance, no higher a temperature
than 37°, 5 c. (100° F.) has been observed,
whilst in the rat and squirrel temperatures of
38°, 8, and of 39°, 4 (102° and 103° F.) have
been noted. To prove that the difference is
less owing to the order or species than to the
simple size, we shall contrast several animals
belonging to the same order, selecting the
ruminants. The temperature of the air being
the same, namely, 26° c. (79° F.), the tem-
perature of the ox was found to be 38°, 9
(102° F.), whilst that of a castrated he-goat
was 39° 5 (103° F.), and that of the she-goat
and sheep 40° (104° F.).*

It is evident that smallness of size must in
itself be one of the conditions unfavourable to
height of temperature among animals, when
this is merely viewed in relation with the am-
bient medium. As the external temperature is
almost always lower than that of the bodies of

* Vide Observ. of Dr. Davy.

animals, the ambient medium tends to lower
their temperature ; and small bodies having a
more extensive surface in reference to their mass
than large bodies, small animals must have a
greater tendency to lose heat than larger animals.
But, on the other hand, the circulation and
respiratory motions generally increase in rapidity
in proportion to the smallness of size ; and we
have seen that acceleration of these motions
had an influence in keeping up the temperature.
With a small size of the body, consequently,
we find associated a higher activity of function
which tends to compensate the disadvantage
resulting from inferior size in reference to tem-
perature. In fact it constantly happens that
this higher activity more than compensates the
cooling disposition from inferiority of size, and
causes the balance to incline towards the side of
higher temperature. It must be apparent,
however, that there is no occasion for such a
preponderance always existing in the case of
small animals. And then we know that the
motions of circulation and of respiration cannot
be greatly ^accelerated without causing incon-
venience and even danger to health and life.
It follows that the external temperature being
liable to fall disproportionately low, small ani-
mals have not, under like disadvantageous cir-
cumstances, the same power as larger animals
of supporting their temperature. The relations
of size naturally lead us to consider those that
depend on age.

Relations of age with animal heat. — The
size of the body changes with the age. The
same relations between bulk of body and de-
velopment of heat ought therefore to be ex-
hibited in youth as compared with adult age.
In early life the greater rapidity of the motions
of circulation and respiration, all things else
being equal, ought to increase the heat. At
the same time the constitution differs in other
respects, and if these were unfavourable to the
evolution of heat, it would be impossible to
foresee the result of these two opposite ten-
dencies. Nevertheless it is probable, from
what we have seen to happen in warm-blooded
animals of different sizes, that there might
occur a period in early life when the heat would
be higher than in adult age. A confirmation
of this inference may be found in comparing the
different observations of Dr. Davy, who has
given a table of the temperatures of fifteen chil-
dren from four to fourteen years, the mean age
of the whole being nine years and nine months.
The mean temperature of the bodies of these
children was 38°, 31(101° F.). But the mean
temperature of twenty-one adults was no higher
than 37°, 82 (100° F.); a difference that seems
the more worthy of being confided in from the
temperature of the air having, at the time of
the observations, been more favourable for the
adults than for the children, this having, in re-
ference to the former, been 26° and 26°, 7
(79° and 80° F.), whilst when the latter were
made the subjects of investigation, it was but
24° and 26° (75°, 5 and 79° F.).

It seems impossible, therefore, to doubt from
what precedes, that size is not an element
which has much influence in the particular

ANIMAL HEAT.

663

direction we are considering. We have seen
that with a decrease in the size of adult Mam-
malia the circulatory and respiratory motions
were progressively accelerated, and that by this
means the disadvantages as regards cooling in
consequence of a smaller relative size of the
body, are in some measure compensated, some-
times, indeed, we have seen the balance in-
clined the other way, and the greater rapidity
of the motions more than compensate for the
diminished size of the body. Great rapidity
of the respiratory and circulatory motions may
co-exist with other organic conditions having
an opposite tendency as regards temperature ;
and, according to the relations of these, and
as the one or the other predominates, we may
have two different states of temperature in
early life. This proposition is even made ap-
parent when we compare the constitution in
early youth and in adult age. In early life the
celerity of the motions has led to the belief
that all the functions of nutrition were pecu-
liarly active. But strength or energy is not
always an accompaniment of simple celerity ;
on the contrary rapidity is generally indicative
of absence of power. It is quite true that in
early life not only are circulation and respira-
tion, but digestion, assimilation, and growth
likewise, much more rapid than in the adult
state. But does it follow from this that the
materials of the blood are elaborated in the
same degree of perfection, or that the products
of the action and contact of this fluid, the
various tissues, &c. of the body, are all as com-
pletely formed ? Everything conduces to make
us believe that the reverse is the case. If on
the one hand rapidity of movement be a cha-
racter of early life, weakness is a feature still
more manifest. If the nervous system there-
fore, although acting rapidly, is less energetic,
in the same proportion there may be an age at
which the influence of this weakness on the
production of heat may be manifest. And, as
the weakness is greater as the being is younger,
it is in the very earliest periods of independent
existence that this relation must be inves-
tigated. Now such a relationship does actually
exist, although an opinion to the contrary had
always been entertained until direct experi-
ments settled the question definitively. These
experiments were performed by the writer, and
a summary of them is here given. If the
temperature of new-born puppies lying beside
their mother be taken, it will be found from
one to three degrees inferior to that of the
parent. The same thing obtains in regard to
the young of the rat, the rabbit, the guinea-pig,
&c. and is probably universal among the Mam-
malia. Among Birds the same circumstance
presents itself in a still more marked degree.
If they be taken out of the nest in the first
week or even fortnight of their existence, the
difference of temperature extends to from 2°
to 5° c. between the young and the parents.
The fact has been ascertained in regard to the
sparrow, the swallow, the martin, the sparrow-
hawk, the magpie, the thrush, the starling,
&c. &c., and is probably, as among Mammalia,
universal. Whence we may conclude that the

phenomenon is general as regards warrrt-blooded
animals. We might have taken it for granted
that man was comprised within the category,
but it is just as well to have the assurance that
he forms no exception to the law, that he has
no peculiar privilege in this respect. To have
a precise term of comparison, the temperature
of twenty adults was taken at the same time,
the thermometer being applied in the axilla.
The temperature of these twenty persons varied
between 35°, 5 and 37° c. (96° and 99° F.) ;
the mean term was therefore 36°, 12 (97° F.).
The temperature of ten infants varying from a
few hours to two days in age, ascertained in
the same manner, varied between 34° and 35° 5
c. (93°, 5 and 96° F.). The mean was there-
fore 34°, 75 c. (about 94°, 5 F.). There was
consequently a difference of nearly two degrees
between the temperature of the adult and of
the newly born babes. Man is therefore proved
to be subjected to the same law here as ani-
mals having warm blood in general, the young
of which, so far as they have been examined,
and we may presume universally, are inferior
in temperature to their parents.

There are, therefore, two periods in youth at
which the bodily temperature differs from that
of the adult age. These may be distinguished
as the first and second periods of infancy or
youth. The first extends from birth to an in-
definite period, but which is nearer or more
remote from the period of birth in different
cases. The second is included between the
fourth and the fourteenth year ; the limits can-
not be more accurately determined. In the
first the temperature is lower than in adult age,
in the second it is higher. The differences of
temperature in the first age of infancy, and the
adult age, although very sensible and impor-
tant as regards the economy, are indices of a
difference incomparably greater than their
numerical indication might be taken to imply.
In fact, if the manner of observing be altered,
results of so extraordinary a character are come
to as to surpass all expectation. To deve-
lope these the temperature of the newly bom
being must not be taken only when it is in
contact with its mother. If, after having as-
certained the temperature of a puppy in this
position, it be removed from the mother and
kept isolated, the temperature will be found to
fall rapidly ; and this phenomenon takes place
not only when the air is cold, but when it is
mild. The phenomenon does not commence
after a term ; it is apparent from the moment
the separation takes place, and is very sensi-
ble after the lapse of a few minutes. The fol-
lowing is the rate of cooling of a puppy twenty-
four hours old, the external temperature being
13° c. (about 55°, 5 F.), taken at intervals of
ten minutes; the series of course represents
the successive losses of temperature in the
course of the small intervals of time indicated :
— temperature in commencing the observations
36°, 87 c.; the declensions in temperature at
intervals of ten minutes successively, 0°, 63,
1°, 12, 1°,38, 1°,25, 1°,29, 0°,87, 1°,63,
0°, 25, 1°, 0; in thirty- five minutes the tem-
perature declined fart tr 1°,25; in thirty-five

664

ANIMAL HEAT.

minutes more it fell 3°, 12 ; in thirty minutes
more 2°, 50 ; in twenty-five minutes more
1°, 25; in thirty minutes morel0, 25; so that
in the course of four hours in all the tempe-
rature declined by the amount of 18°, 12 of
the centigrade scale (about 33° F.) ! Not only
had the temperature of the animal sunk by so
large a quantity in so short a period of time,
the external temperature being pleasant, but it
actually could maintain its temperature at no
higher a grade than 6°, 75 c. (44°, 5, F.) above
that of the atmosphere. Experiments of the same
kind performed on three other puppies of the
same litter presented results in all respects
analogous. The cooling may even go much
further by protracting the period during which
the young animals are kept apart from their
parent. For instance, four puppies, twenty-
four hours old and of much smaller size than
the subjects of the former experiments, after
having sunk 16° c. in four hours and thirty
minutes, lost six degrees more of temperature
in the succeeding eight hours and thirty mi-
nutes, the air remaining all the while at 13° c.
(53°, 5 F.). They consequently lost twenty-
two degrees centigrade in thirteen hours ; and,
•what is very remarkable, their final temperature
was but one degree above that of the surround-
ing air. Kittens and rabbits of the same age
exhibited similar phenomena, if possible in a
more striking degree. Some kittens were ob-
served to cool twenty degrees centigrade within
the short interval of three hours and a half,
and some young rabbits suffered the same de-
pression of temperature in two hours and ten
minutes, the air being at the time at 14° c.
(57°, 5 F.), These phenomena are unques-
tionably among the most remarkable we wit-
ness in warm-blooded animals. For here we
have species of different genera of the Carni-
vora and Ilodentia, which at two periods of
their existence present the extremes in the pro-
duction of heat. They may be said to be,
to all intents and purposes, cold-blooded ani-
mals, with reference to temperature, during
the earliest period of life; they are only truly
warm-blooded animals in a later stage of their
existence. The same phenomena undoubtedly
present themselves in many other species ; but
it would not be reasonable to suppose that they
were exhibited by all.

The phenomena being connected with the
state of constitution, it may be expected to
vary in different genera and families; and this,
in fact, is what actually happens. A young
guinea-pig, for instance, having a temperature
of 38° c. (101°, 5 F.), will maintain this tem-
perature when the atmosphere is mild, although
separated from its mother. It is the same with
the goat. These instances are enough to give
us a key to the external characters in relation
with the different capacities to produce heat
inherent in the young Mammalia. In the first
place we observe a manifest relation with the
state of energy of the nervous system : on the
one hand we have the puppy, the kitten, the
rabbit, which are born extremely weak ; on the
other we have those animals that come into the
world in a condition to walk, to eat, and, as it

were, furnished forth to a certain extent with
the means of providing for their wants. The
question, however, is to discover some zoolo-
gical character in relation with these differ-
ences. If this were to be derived from the
state of the organs of locomotion, of the faculty
of walking, we should sometimes be led into
error ; for man, at the period of his birth and
long afterwards, is not in a condition to hold
himself erect, and yet his temperature is main-
tained to within one or two degrees of that of
his mother, if the external temperature be but
mild. There is, however, one character that
appears general ; this is the state of the eyes.
2'hose species of Mammalia which in the earlier
period of their existence do not maintain their
temperature, that of the external atmosphere
being mild or warm, but cool down to the
standard of the cold-blooded animals, are born
with their eyes closed ; whilst those which main-
tain their temperature, that of the external
atmosphere being mild, are born with, their eyes
open ; and this, whether they can walk about
like the guinea-pig, the kid, &c., or cannot do
so, as is the case with the human infant in par-
ticular.

This general view of the state of energy of the
nervous system in relation with the production
of heat in early life, comes in aid, in a very
remarkable manner, of the general principles
which have been already deduced in regard to
the calorific power. In going more deeply
into the subject, the confirmation becomes more
manifest and more complete. The state of the
eyes affords a mere external and zoological in-
dication. It is but an indication of other deep
modifications of the economy, which it is
essential to determine more closely. Now in
examining the state of the organs generally of
puppies at the period of their birth, we observe
a remarkable disposition of the sanguiferous
system. The ductus arteriosus continues per-
vious and of large size. The consequence of
this structure is that a free communication is
established between the arterial and venous
blood, by which they are mingled in large pro-
portion one with another. And here we have
precisely the physiological character derived
from the nature or quality of the blood which
distinguishes the cold-blooded from the warm-
blooded Vertebrata (in the adult age under-
stood). This character is exactly the same in
the other species of Mammalia which we have
mentioned as losing temperature and attaining
the standard of the cold-blooded tribes. On
the other hand, in the guinea-pig, to take an
individual instance, which from the first day of
its extra-uterine existence maintains its tempera-
ture nearly on a level with that of its parent
when the air is temperate, the ductus arteriosus
is closed immediately after birth. The arterial
remaining distinct from the venous blood, this
creature is therefore born with the organization
characteristic of warm-blooded animals, and
presents phenomena having reference to calori-
fication of the same kind as adult warm-blooded
animals.

This relation is preserved in the young
Mammalia in every modification in a pecu-

ANIMAL HEAT.

665

liarly interesting manner. The young Mam-
malia which are born with the eyes closed, at
first present the phenomena of refrigeration
nearly in the same degree during this two or
three first days of their life; though they after-
wards exhibit differences of great extent in this
respect. Thus a young rabbit two days old had
cooled down to 14° from 23° c. (to' 58° from
74° F.) in the course of three hours fifty minutes,
the air being at the time temperate ; another three
days old took seven hours twenty-five minutes
to cool through a range of 18° c., when the
process of refrigeration ceased. A third, of the
age of five days only, lost 5°c. in temperature
in the course of one hour fifty-five minutes,
and maintained itself afterwards at this tem-
perature. During the following days, smaller
and smaller depressions of temperature were
observed, till the eleventh day after birth, when
the power of sustaining the temperature a little
below that of the adult female parent seemed to
be acquired permanently. \Vhen the modifi-
cations of internal structure are examined
during this interval of time, we find that the
ductus arteriosus has been contracting in the
same proportion as the faculty of maintaining
the temperature has been increasing, and that it
is entirely closed at the epoch when the tem-
perature becomes stationary, the external tem-
perature being understood all the while as
mild or pleasant. At the same period pre-
cisely too, the eyes are unsealed, a circum-
stance which confirms the exactness of the
character derived from the state of this latter
organ, as distinctive of the young of those
Mammalia which are born as it were cold-
blooded animals, from those that come into the
world with the distinguishing attribute of warm-
blooded animals.

Among the young of Birds we observe as
marked differences in the calorific function as
we have just acknowledged among Mammalia.
Some lose heat rapidly when separated from the
mother; others maintain their temperature to
within a little of that of their species. Spar-
rows, for instance, which have been hatched but
a short while, present a temperature from 4° to
5° c. lower than that of their parents when still
contained in the nest, where they contribute to
each other's warmth. But taken out of the
nest and isolated, although the temperature be
that of summer they begin to cool with extreme
rapidity. A young sparrow a few days old
lost as many as 12° c. in the short space of one
hour seven minutes, the air at the time marking
22° c. (72° F.). The same thing happens
with swallows, sparrow-hawks, &c. But the
law is not universal; it does not hold in re-
ference to all the genera. There are several
that have the power of sustaining their tempera-
ture in spring and summer at a degree but
little below that of their parents. Birds, there-
fore, form two groups as regards the production
of temperature, just as the Mammalia do. The
first cool down to the standard of cold-blooded
animals; the second preserve their warmth,
when the air is mild or agreeable as it is in the
spring and summer. But the zoological
characters that distinguish them are not the

same as among mammiferous animals. All
birds are hatched or born with their eyes open.
But there are other characters which coincide
with the difference of temperature; and this
consists in the absence or presence of feathers.
The covering of those that are hatched so pro-
vided, consists in a kind of down, very close
and very warm, so that we might imagine
the differences observed in the liability to lose
heat or in the capacity to engender it, belonged
to the coat. This has undoubtedly some
influence, but analogy even will not suffer
us to ascribe the chief effect to this cause. In
the Mammalia which are born with their eyes
closed, the refrigeration takes place to the same
extent whether they are born with a fur-coat,
as the kitten, the puppy, &c., or come into
the world naked like the rabbit; the cooling is
only more rapid in the latter than in the former.
What further proves, and directly proves, that
the refrigeration is not entirely due to the dif-
ference in the external condition as regards
covering, although this of course must go for
something, is that when the want of natural
covering is artificially supplied, the cooling does
not go on the less certainly on this account,
and to the same ultimate extent ; it only takes
place somewhat more slowly. The counter-
proof is attended with the same result. An
adult sparrow which has had all its feathers
clipped off does not at first suffer loss of tem-
perature to the extent of more than a degree,
and by-and-by recovers even this; whilst a
young bird of the same species, though fur-
nished with some feathers, cools rapidly and to
a great extent, as we have already seen. Birds
are there/ore divided into two groups as regards
the production of heat. The one comprises
those that are hatched with the skin naked, and
which cool in a temperate air in the same
manner a-s cold-blooded animals ; the other
embraces those that are produced with a
downy covering, and maintain their temperature
at a considerable elevation in the ordinary heat
of spring and summer.

There is not a less remarkable contrast
between these two groups of birds in point
of calorific power, than between the two
groups of Mammalia already mentioned ; but
the zoological or external characters which dis-
tinguish them in the present instance are not of
the same kind. The state of the eyes does not
apply here, for all Birds are disclosed with their
eyes unsealed. They also all come into the
world with the ductus arteriosus closed or nearly
so, — a circumstance which might have been
predicated, or inferred from analogy. Yet the
young of Birds in the power of producing heat
present diversities no less remarkable than are
observed among the young of the Mammalia.
The separation of the two kinds of blood con-
sequently is not the only condition which
influences the production of heat; but all that
modifies the blood on the one hand, and the
nervous system on the other, as we have had
occasion to observe in a previous part of this
paper. Now it happens that we have an op-
portunity of applying this principle in a very
particular manner in the instance of the two

666

ANIMAL HEAT.

groups of Birds that engage us, and that
differ so essentially in their powers of engender-
ing caloric. In the one and in the other we
observe the same difference in the state of the
general strength which we have observed in the
corresponding groups of the Mammalia. In
the one which cools rapidly, there is the same
state of weakness, of general impotency; in the
other the young are in a condition to walk, and
in a certain sense to shift for themselves as soon
as they have escaped from the shell.

We perceive then in the first place, that the
nervous system is much less energetic in the
former than in the latter group ; and in the
second place, that the digestive powers are in an
equal degree inferior in strength ; for they are
not only unable to take food of themselves from
muscular incapacity, but also from the lack of
the requisite instinct, and, farther, from their
digestive organs not being in a condition to
elaborate food to any extent. It is on this last
account that the parents supply their young
with food which has suffered maceration in
their own crops, or has even in their stomachs
undergone a kind of incipient or partial solu-
tion ; or otherwise the parents have the instinct
to select such articles as are easiest of digestion,
and best fitted for the weakly state of the
digestive organs of their progeny. We have
already observed that a defect in the powers of
digestion implies a corresponding imperfection
in the blood. Whence we must conclude by
analogy that the blood in the birds of the first
group is inferior in quality to that of the birds
of the second group. We consequently still
find the two general conditions which regulate
the production of heat throughout the animal
kingdom — the state of the blood, the state of
the nervous system.

The same principles are applicable to the
first period in the existence of all animals,
without distinction of groups, as compared with
adults. On the one hand we have ascertained
that all without exception have a temperature
lower than that of their parents ; on the other,
nothing can be more manifest than their inferi-
ority with reference to the energy of the nervous
system. And more attentive and extensive ex-
amination shows that this extends in like man-
ner to the digestive functions, and consequently
to those of nutrition generally.

Let us first turn our eyes to the Mammalia.
All of these are evidently inferior in this respect
to the adult. This is proclaimed in the distin-
guishing character of the class : the females are
provided with glands for the purpose of prepa-
ring a food appropriate to the state of weakness
of their young. The state of the mouth of the
young is a sufficient index of the defective
power of the digestive organs ; the jaws are
either wholly or partially without teeth. The
softness, delicacy, paleness of colour, and insi-
pidity of the tissues of young Mammalia, com-
plete the evidence of the imperfect elaboration
of the nutrient juices. If, therefore, the first
and last products of the nutritive functions are
in an inferior condition, can we suppose that
the intermediate product, the blood, will not
participate in this inferiority? We have already

shown in what this consists among the Birds of
the first group. With regard to the second, the
general considerations relative to the difference
of the tissues is equally applicable to them, and
these considerations possess a high value.
When very young warm-blooded animals, with-
out any exception, are compared in this respect
to the cold-blooded Vertebrata, we perceive a
great analogy in their component tissues, which
are softer and less savoury than among the
adults of warm-blooded animals. It is thus
that we can account for a striking anomaly in
the nervous system of young warm-blooded
animals, especially Mammalia. Their nervous
system, particularly the encephalon, bears a
higher proportionate ratio to the whole body
than it does in the adult ; but the softness and
the other characters of the tissue of this organ
in early life cause it to approximate in a re-
markable manner in appearance and character
to the same tissue in the cold-blooded Verte-
brata. If, therefore, the relative volume predo-
minate in early life, one of the conditions
favourable to calorification, the inferiority in
respect of tissue counterbalances this advan-
tage, and is only compatible with very inferior
manifestations of energy.

It is obvious then that there is a universally
pervading analogy between warm-blooded ani-
mals in the first stages of their existence and
adult cold-blooded Vertebrata, and that the pa-
rallel holds good, not merely with reference to
their inferior power of producing heat, but also
with regard to the functions of nutrition gene-
rally and the functions of the nervous system.
There is one point upon which it is highly ne-
cessary to insist, inasmuch as it is of the greatest
importance, both theoretically and practically ;
it is this : that the analogy in the direction in-
dicated is by so much the more remarkable as
the warm-blooded animal is born with charac-
ters which distinguish it more strikingly from
those it possesses when arrived at maturity. If
it is born with the eyes closed, or without fur
or feathers, instead of with the eyes open and
the body covered with a fur coat or a thick
down, it is because the creature comes into the
world less perfectly developed in every respect,
and the whole economy is more closely allied
to that of inferior orders. This, in other words,
is as much as to say that the creature is born
at a period relatively precocious, or in a more
imperfect condition. Whence it may be in-
ferred that those warm-blooded animals which
are born at a period short of the ordinary term
of utero-gestation among the more perfect spe-
cies, will present a more marked analogy with
the cold-blooded tribes. Man himself will
form no exception to this rule, which must be
quite general. The verification of this law has
been completed by the physiological experiments
of the writer. A child born at the seventh
month, perfectly healthy, and which had come
into the world with so little difficulty that the
accoucheur could not be fetched in time to re-
ceive it, had been well clothed near a good fire
when the temperature was taken at the axilla.
This was found no higher than 32° c. (under
90° F.). Now we have seen that the mean of

ANIMAL HEAT.

667

the temperature of ten children born at the full
time was 34°,75 c. (94°,5 F.) ; the tempera-
ture in no case descending lower than 34°
(94° F.), and ranging between this and 35°,5 c.
(96° F.). Let it be observed that at the
seventh month the membrana pupillaris no
longer exists ; the infant has, therefore, at this
epoch of its development, the essential charac-
ters of warm-blooded animals capable of sup-
porting a high temperature when that of the
surrounding atmosphere is mild. But if it
were entering the world some considerable time
before the disappearance of the pupillary mem-
brane, it would be in a condition analogous to
the Mammalia which are born with their eyes
shut ; it would no longer be in a condition to
maintain an elevated temperature, and without
doubt would lose heat precisely as they do
without precautions to the contrary.

When we take a general view of the first and
second periods in the early life of warm-blooded
animals, we find that they are under the influence
of two general conditions relative to calorifica-
tion ; conditions which, acting inversely, tend
to compensate each other mutually ; on the
one hand, the celerity of the motions ; on the
other, the imperfection of the nutrient and ner-
vous functions. The celerity of the motions of
circulation and respiration diminishes, whilst
the development of the nutritive and nervous
functions increases with age. These two con-
ditions influencing the production of heat are,
therefore, in an inverse ratio to one another.
And according to the nature of these relations
will the temperature vary. Were the opposite
effects equal, there would be exact compensa-
tion in the whole phases of the evolution, from
the moment of birth to that of perfect adole-
scence, and the temperature of the body would
be the same at every period of life. But the
progression in the celerity of the movements on
the one hand and of corporeal development on
the other, is unequal ; and there is but a single
epoch in the whole course of childhood when
such an equality or balance exists, and at
which consequently the temperature of the
child is the same as that of the adult. Previous
to this epoch, the nutritive and nervous func-
tions are so imperfectly developed, that their
influence, inimical to the production of heat,
surpasses the favourable tendency to this end,
which we have in the celerity of the motions of
circulation and respiration. It follows that the
temperature of the body is inferior at the pre-
ceding limit or to that of the adult state ; with
the progress of time, however, the child attains
this limit, and then we have a new relation
established. The evolution of the nutritive and
nervous functions continues, and although it
have not yet attained its ultimate term, the de-
fect of heat which results from this is all but
compensated by the celerity of the motions,
which is still sufficiently great, to surpass in a
marked degree the celerity of the motions in
the adult. The temperature at this period will,
therefore, be above that of the adult. This pe-
riod lasts for several years in childhood or
youth ; but then comes a gradual retardation
in the motions both of respiration and circula-

tion, and with this a reduction of the tempera-
ture to the standard of the adult.

There are consequently four states of the
temperature from birth up to adolescence inclu-
sive. In the first period the temperature is at
the minimum ; in the second, it attains the
adult degree ; this might be entitled the period
of the mean temperature ; in the third, the
temperature exceeds that of the adult; finally,
in the fourth, it sinks to the mean, that is,
the temperature of the adult.

There are, therefore, constitutions in the same
class of animals which are more or less favour-
able to the production of heat ; for it is so
among individuals that differ in age in the
limits between the moment of birth and
that at which adolescence is completed ; and
this leads us to new considerations.

DIFFERENCES OF CONSTITUTION IN RELATION
WITH THE PRODUCTION OF HEAT AMONG
ANIMALS.

Since the body and the functions are pro-
gressively developed, and without interruption
between the two grand periods named, there is
in the course of this long interval as much dif-
ference in the state of the constitution as there
are sensible degrees of development ; a circum-
stance that implies a long series of varieties.
But these intimate differences are not mani-
fested externally by corresponding states of
temperature of body. For we have seen that
this undergoes but four sensible variations in
this respect, and that, of these four modifications,
two were of like import. It is every way
worthy of attention to observe that, at the point
which separates the first from the second period
of infancy, the temperature should be equal to
that of the adult.

It is difficult to imagine that this equality
can exist under every variety of external cir-
cumstance, when we see that the elements upon
which it depends are so different. And this
leads us to consider the production of heat
under a new point of view. Under what cir-
cumstances has this equality of temperature be-
tween the infant and the adult been observed ?
It was when the external temperature was mild
or even warm. Would the same thing have
been observed had this been cold or severe ?
It is evident that if the faculty to produce heat
is the same at this period of infancy as it is in
adult age, the heat of the body will always re-
main the same, making abstraction of the diffe-
rences that depend on those of simple corpo-
real bulk. Thus, all things else being equal, a
young animal at this epoch ought to cool to the
same degree as an adult under the influence of
external cold, if it have the same power of pro-
ducing heat. If, however, it be inferior in its
calorific powers, it will not be competent to
maintain its temperature to the same degree as
the adult, and it will fall under this limit in a
proportion determined by the difference which
exists in the faculty of producing heat. On
making application of the principles which
have been already announced, let us try if we
cannot predict the effects. By reason of the
inferiority in energy of the nervous system in

668

ANIMAL HEAT.

early life, it is difficult to suppose that a young
animal will resist the action of intense cold in
the same manner as an adult. This inference
is fully borne out by the following experiment.
A young guinea-pig a month old, the tempe-
rature of whose body was high and steady, the
temperature of the external air being mild, was
exposed along with an adult to the same decree
of diminished temperature — the air was at 0°c.
(32° F.). In the course of an hour the young
creature had lost 9° c. in temperature, whilst
the adult had only lost 2°,5 c. This experi-
ment, repeated several times with the same
species of animal, always gave the same result.
Young and adult birds of the same species,
treated in a similar manner, showed the same
diversity in their powers of resisting the effects
of external cold, from which we may infer that
the law is quite general. Several young mag-
pies, for instance, whose temperature was sta-
tionary in a mild spring atmosphere, were
placed with an adult in air cooled to +4° c.
After the lapse of twenty minutes, one of the
young ones was found to have lost 14° of tem-
perature. The others, examined at intervals,
none of which exceeded one hour and ten mi-
nutes in length, had cooled from 14° to 16° c.
The adult bird, on the contrary, similarly cir-
cumstanced, did not suffer a greater depression
of temperature than 3° c. The loss of heat
sustained by the young birds was so great as to
be incompatible with life, if continued ; that
endured by the old one was trifling in amount,
and not inconsistent with health. It is quite
true that the difference in point of size and
quantity of plumage has an influence upon this
inequality of cooling ; but at the period of de-
velopment, when the experiment was tried, the
difference was not remarkable in regard to
either point ; nevertheless it is only proper to
take notice of it. By prolonging the period
during which the adults were exposed to the
cooling process, the advantages they derive
from their greater size and closer plumage may
be counterbalanced or compensated. It is es-
sential to observe that iu the course of the first
hour the adult bird had only lost temperature
in the proportion of one-fifth of that lost by the
young birds, which obviously bears no ratio to
the difference in point of size, plumage, &c.
And then, the operation of the cold being con-
tinued, the adult suffered no further depres-
sion of temperature : it fell three degrees cen-
tigrade, and then became stationary. We can-
not, therefore, ascribe the entire difference in
the cooling to that of the physical conditions of
size and plumage ; a difference of constitution
must go for a great deal ; there are inherent
diversities of constitution, favourable or the re-
verse, to the production of heat. The truth of
this conclusion appears much more clearly if
we continue to subject young birds to the same
kind of experiment at successive epochs not so
close to one another. The rapid progress they
make in the power of evolving heat is, indeed,
a very remarkable fact. A few days later, and
they lose temperature in a much less considera-
ble degree when exposed to cold under the
same circumstances, although there was little

or no apparent difference in the external appear-
ance of the birds. And this is a new and con-
vincing proof that the inequality in the disposi-
tion to lose heat obvious at different periods
of life under exposure to a low external tempe-
rature, is principally owing to inherent inequa-
lity in the faculty of producing caloric.

It is of great importance that a precise idea
be formed of this expression. Up to a very
recent period in the investigation of animal
heat, no one thought of comparing animals
save with reference to the temperature of their
bodies only : and when it was found that this
was the same or different by so much, the ac-
count was closed, the comparison was pushed
no farther, under the impression that every
thing was included under this single ostensible
character. Undoubtedly, it must be granted
that, all else being alike, equality of tempera-
ture is an indication of equality in the capacity
to produce heat. But animals in one set of
circumstances may actually produce the same
quantity of caloric, and not continue to do this
the circumstances being changed. It is of
consequence to distinguish the actual produc-
tion, from the power to produce under different
conditions. The one is an act, the other a fa-
culty, a distinction of the highest importance in
philosophical language in general, and espe-
cially in that of physiology. But animals of
the same size, subjected to the same variations
of external conditions, if they continue to ex-
hibit corresponding degrees of temperature,
whether these are higher or lower, have evi-
dently the same faculty of producing heat. If,
on the contrary, they present different degrees
under the influence of precisely similar exter-
nal variations of circumstance, it is obvious
that they must possess the faculty of producing
heat in different degrees. Unless we be actu-
ally persuaded of the value of this expression,
so simple in other respects, and so constantly
held in view in all analogous circumstances,
the study of the phenomena of animal heat
would remain as it were barren, whilst the in-
vestigation of the diversities of constitution in
relation with this faculty is fertile in interesting
and useful applications.

We have seen how constitutions differed in
this respect according to age in the earlier
period of life and in the adult state. It is
probable that there are other varieties depend-
ent on other causes ; for example, differences
of season, climate, &c. This point it will be
our next business to examine.

INFLUENCE OF SEASONS IN THE PRODUC-
TION OF ANIMAL HEAT.

The temperature of an animal is the result,
1st, of the heat which it produces ; 2d, of that
which it receives ; 3d, of that which it loses.
The proportion of heat which is lost depends
on two principal conditions, the relatively
colder temperature of the atmosphere, and the
amount of evaporation that takes place from
the surface of the animal. In cold and tem-
perate climates these two conditions of cooling-
are in inverse relations to one another in the
opposite seasons of winter and summer. In

ANIMAL HEAT.

669

winter the temperature of the air is lower ; in
summer the amount of evaporation greater.
These two conditions of refrigeration, therefore,
tend to compensate one another, and conse-
quently to maintain the equilibrium of tempe-
rature as regards the body in the two opposite
seasons. They have unquestionably a consi-
derable share in this business; and it was long
believed that the simple difference indicated in
the external conditions sufficed to preserve the
temperature of the body alike during the two
periods. But in reflecting on the phenomena
presented by cold-blooded animals with the
changes of the seasons, which have already
been spoken of at length, we find such an opi-
nion or view to be inadmissible. For in ex-
amining those species of cold-blooded animals
which from their structure are liable to lose
more by evaporation than any other animal,
we see that no such compensation takes place.
Frogs, for example, the skin of which is so soft
and permeable, and whose bodies besides are
so succulent that they must be presumed in the
most favourable circumstances to sustain loss
by evaporation, ought to preserve the same
temperature in winter and in summer if the
low temperature in winter were compensated
by the excess of evaporation in proportion as
the heat of the season augments. But we
know that the temperature of these creatures
follows, to a very great extent, that of the at-
mosphere, between 0° and 25° c. (32° and 77°
F.), differing at no time from it by more than a
degree or two. The phenomenon here is sim-
ple, by reason of the slight evolution of
caloric by the frog, and leaves no doubt upon
the mind. We must, therefore, have recourse
to other conditions, in order to explain the
slight difference that is observed in the summer
and winter temperature of man and other warm-
blooded animals. Since external conditions
do not appear to explain the phenomena, it
must undoubtedly mainly depend oncertain
changes effected in the animal itself. Now,
since the internal conditions which influence
the temperature of the body are those also that
regulate the production of heat, it is here that
the change must be effected.

It is obvious that the cause of refrigeration
in winter being more active, to meet the greater
expenditure there must be the means provided
for furnishing a larger supply — the calorific
faculty must be more active in winter than in
summer. The inverse of this takes place in
summer; so that the temperature of the body
in the two seasons is determined in the follow-
ing manner: — in winter there is a more active
production with a greater loss ; in summer a
less production, with a smaller /ossof heat. In
this way is there compensation, and a perfect
equilibrium maintained at all seasons. To
render this relation more evident, it may be
expressed in another manner ; as, for example,
in summer the body receives more heat from
without, and produces less ; in winter it receives
less and produces more.

These considerations carry us farther. As
this difference in the production of heat lasts as
long as the various seasons, and takes place

progressively, it is to be presumed that it be-
longs to an intimate and more or less en-
during change effected in the state of the
body. In other words, the constitution alters,
and the faculty of producing heat changes in
the same degree. The fact thus expressed is
immediately susceptible of an interesting ap-
plication. If the faculty of producing heat is
less in summer, the temperature of the body
will not be maintained to the same point in the
two seasons under sudden exposure to the
same degree of cold. By subjecting animals
to the test of experiment in the two seasons, it
is easy to judge of the justice of the preceding
deductions, as well as of the principles which
led to them. To have the mode of refrigera-
tion precisely the same, attention must be had
not merely to the thermometric temperature of
the air, but also to its humidity, which ought
to be the same in both instances. A difference
in the hygrometrie state of the air will certainly
produce a difference in the effects of refrigera-
tion. The apparatus employed consisted of
earthen vessels plunged amidstaquantity of melt-
ing ice. Air thus cooled soon reaches the point
of extreme humidity. The air being at zero c.
(32° F.), the animal is introduced, placed upon
a stage of gauze to prevent its coming in con-
tact with the moist and rapidly conducting
surface of the vessel. A cover, also piled over
with ice, is then placed over the apparatus, but
so arranged as still to permit the ready reno-
vation of the air contained in the interior.
Still farther to secure the purity of the included
air, a solution of potash, which of course ab-
sorbed the carbonic acid produced with avidity,
occupied the bottom of the vessel. In winter,
in the month of February, the experiment was
made at the same time upon five adult spar-
rows, which were all included in the apparatus.
At the end of an hour they were found one
with another to have lost no more than 0°, 4 c.,
or less than half a degree; some of them
having suffered no depression of temperature
whatsoever, others having lost as much as, but
none more than, 1° c. The temperature of the
whole then remained stationary to the end of
the experiment, which was continued for three
hours. In the month of July the same expe-
riment was performed upon four full-grown or
adult sparrows. The temperature of these
birds at the end of an hour had undergone a
depression, the mean term of which was 3°,
62, and the extremes 6°, 5 and 2° c. At the
end of the third hour the mean term of the
refrigeration suffered was 6°, the extremes being
12° and 3°, 5 c. It ought to have been stated
that in the experiment in the winter month,
the birds had been for some time kept in a
warm room, so that the sudden transition was
the same in both instances, in the winter as
well as the summer experiment. The diver-
sity in the constitution of these birds, conse-
quently, with reference to the powers of pro-
ducing heat, was an effect of the difference of
the seasons. Each month the temperature of
which differs in any degree from that of the
month before or after it, has an obvious ten-
dency to modify the temperament or constitu-

670

ANIMAL HEAT.

tion in the manner which has been indicated.
In summer we may presume, nay we may be
certain, that the differences obtain in degree
according to the mean intensity of the heat
proper to each. This is even to be proved by
direct experiment. The month of August, as
commonly happens, was not so hot as the
month of July, and six sparrows treated in the
same manner as those that were the subject of
the July experiment already detailed, were
found not to suffer refrigeration to the same
extent. After the lapse of an hour the mean
temperature of the six had sunk 1°, 62, and
after three hours 4°, 87 c., from which it is ob-
vious that with the successive declensions of the
external temperature the faculty of engendering
heat increases. This is demonstrated by the
experiments quoted. The animals that were
the subjects employed suffered a relatively less
degree of refrigeration in the cooler month than
they had done in the hotter, when exposed to
the same measure of cold. In the first set of
experiments performed in one of the coldest
months of the year, the power of resisting cold
was made particularly manifest. The sparrows,
kept for three hours in an atmosphere at the
temperature at which ice melts, scarcely suffered
any loss of heat at all. The results of the
three series of experiments detailed confirm, in
every particular, the conclusions which had
been come to analogically and a priori. They
do more than this. They bear out equally the
principles which had been deduced with refe-
rence to the constitutions more or less favoura-
ble to the production of heat. It is apparent,
in the first place, that the influence of the
summer and that of the winter act on the con-
stitution in the same manner as the two opposed
periods of early youth and adult age. Let us
therefore inquire in what manner these different
conditions tend to produce analogous effects.
We have seen that the constitution of early life
differed from that of adult age, especially in
the inferior energy of the functions of innerva-
tion and nutrition. Now this is that which
constitutes or causes the principal difference
between the winter and summer constitution of
man. We generally feel ourselves weaker in
summer than in winter, and our digestive
powers are then also decidedly less vigorous.
What completes the analogy is that the motions
of circulation and respiration are accelerated in
summer; and as a complement of the whole
of these data, the temperature is somewhat
higher in summer ; just as we have seen
that there is an epoch in youth when the tem-
perature exceeds that which is proper to com-
plete manhood. Thus, the parity between
the constitution of youth (in the second period
of childhood,) and that of the body in sum-
mer, contrasted with the constitution of the
adult age and that of the body in winter, exists
in the three following relations : — 1st, a lessened
faculty of producing heat ; 2d, greater activity
in the motions of circulation and respiration ;
3d, a higher temperature of the body.

But this faculty of adaptation to the different
seasons inherent in the body is only observed
in the better constitutions. That it may be

manifested, it is necessary there be present a
certain energy of the nervous system ; without
this even the moderate colds of winter will not
be resisted. Without this the adult will have
a constitution that will present analogies with
that of early infancy. At present we merely
mention the kind of constitution ; we shall
return to the subjectby-and-by.

Differences according to the nature of the
climate. — The preceding facts render direct ex-
periments to ascertain the influence of the tem-
perature of different climates on the calorific
power altogether unnecessary. This is so far
fortunate ; for it were no easy matter to institute
them to the extent and with the precautions
necessary to security and satisfaction. The
knowledge of these effects is a necessary con-
sequence of the researches that precede. The
temperature of warm climates is represented by
the summer temperature of temperate climates,
with this difference, that it is higher, and that
with slight variations it continues through the
whole year. Whence it follows that warm
climates taken generally must produce effects
upon the constitution analogous to those pro-
duced by summer with us, only of greater
intensity by reason of the higher thermometric
range and longer continuance of the heat. The
inhabitants of hot climates ought consequently
to have an inferior degree of calorific power
than those of temperate or cold countries, what-
ever be the season. And we find, in fact, that
the natives of the warmer latitudes of the earth
present the characters in general that distinguish
the constitution of the body in the summers of
temperate countries, and characterizes the second
period of youth — more rapid motions of the
circulatory and respiratory systems, and a
higher temperature, conjoined with an inferior
degree of energy in the functions of innervation
and nutrition.

We shall not here enter upon the examina-
tion of the effects upon the natives of these
warmer latitudes from change of climate. We
shall speak of this elsewhere. After the periodi-
cal changes depending on the seasons we shall
pass to others of shorter duration, but which
revert much more frequently, and are under the
influence of other causes.

INFLUENCE OF SLEEP ON THE PRODUCTION
OF HEAT.

In the course of the twenty-four hours the
body is in two very different and in some sort
opposite states — the states of sleeping and
watching. These two states are principally
contrasted in the energy and weakness of the
nervous system: from a perfect consciousness
of all that is passing, we suddenly observe a
complete suspension of this office in the whole
circle of the functions of relation. At the same
time the motions of the circulatory and respira-
tory system become slower. No more is needed
to lead to the conclusion that in this state the
temperature must be lower ; this is an inference
we draw without risk of error. But the degree
in which these motions are retarded is ex-
tremely limited ; and the depression of tem-
perature must be expected to be in the same

ANIMAL HEAT.

671

proportion : it is in fact very slight, although
appreciable. What would happen were the
retardation in the important motions mentioned
more considerable? The temperature would
suffer a corresponding and great depression,
and various consequences might be conceived
as calculated to ensue. If the degree of cold
did no injury to the economy, the sleep would
last the time required to repair by rest the
energy which the nervous system had dissipated
or lost by its activity during the period of
watching. If, on the contrary, the refrigeration
attained a considerable degree, it would by the
consequent pain stimulate the nervous system
so much as to cause it to wake up to general
consciousness ; but in case the nervous system
were not in a condition to feel this excitement,
in other words to re-act and produce waking,
it would sink into the state of lethargy.

These divers states which we deduce as pos-
sibilities, as what might be expected to occur
in sleep according to the relations of the func-
tions, do in fact present themselves frequently
in nature. It commonly enough happens that
we are aroused from our sleep by a feeling of
cold, although the external temperature has
not changed. With regard to the lethargic
state, although it certainly occurs but rarely,
still it has been acknowledged by the most
respectable authorities, and its occasional occur-
rence seems indubitable. That, however, which
is rare as regards man may be common and
even usual as animals are concerned.

Phenomena presented by hybernating animals
with regard to the production of heat. — If
during the height of summer and during the
state of watching a dormouse or a bat be exa-
mined as to their temperature, this will be
found the same as that of many other warm-
blooded animals. But if either of these animals
be examined whilst asleep at the same season
of the year, the temperature will be found
to have declined considerably. These changes
have been determined by Dr. Marshall Hall,
to whom we are indebted for many ob-
servations of high interest upon the state of
the circulation in hybernating animals. The
writer also observed the same diversities in
the temperature of these animals according to
their state of sleep or watching; but he had
not published his observations at the time Dr.
Hall's paper appeared. Here, then, we have
several species of warm-blooded animals which,
during the hottest season of the year, exhibit
in the two states of sleep and watching a very
marked contrast in regard to the temperature of
their body, which is high during the waking
period, low during that of sleep, the external
temperature having no part in the phenomena.
The difference of temperature coincides very
evidently with the state of the nervous system —
its energy in watching, its enfeeblement in
sleep— a state which we have already seen to
influence in a very great degree the rapidity of
the motions of circulation and respiration,
which are accelerated during the energetic con-
dition, retarded during the period of inaction.
A higher temperature in the one case and a

lower temperature in the other are necessary
consequences.

These facts are interesting under two points
of view. 1st, They show precisely the kind and
extent of the influence which the states of
watching and sleep exert in general on the
production of heat in animal bodies ; 2d, they
are remarkable in the particular instances under
consideration, in this, that the differences exhi-
bited during the two states are extreme. It
must be allowed, therefore, that those animals
in which they take place must have less
energetic nervous systems than other warm-
blooded animals. From this tendency in
the animal economy, there must also be in
different species a diversity rather than an
equality in the degree in which the phenomena
are exhibited. And this is confirmed by obser-
vation. Some cool to a much greater extent
than others during their sleep in the summer
season. They may be said severally to have
just as much nervous energy as is requisite to
sustain a high temperature in the summer
season during their state of highest activity,
i. e. during the period of watching, and no
more. When the state of excitement ceases,
and the collapse that follows excitement
supervenes, the languor manifested is much
greater than that of other animals in the
same condition, and their temperature sinks
in proportion. The energy possessed by hyber-
nating animals seems barely sufficient to enable
them during the summer season to maintain a
temperature of body equal to that of warm-blood-
ed animals in general. They subsequently pre-
sent another phenomenon with regard to their
temperature well worthy of particular attention,
although it be no more than a consequence of the
first. Since it is a defect of energy in the
nervous system during sleep which prevents
their maintaining the degree of rapidity in the
motions of circulation and respiration so essen-
tial in their turn to the maintenance of a tem-
perature of the body but little inferior to that
pertaining to the state of watching in summer,
how are they to preserve their temperature even
during the watching state when the summer
declines into autumn, and the autumn into
winter?

It is evident that if they follow the general
rule their respiratory and circulatory motions
will be retarded with the fall of the atmospheric
temperature, and this by so much the more as
their nervous system shows a less degree of
energy. It is even presumable that owing to
the decline of atmospheric temperature in
autumn, they will exhibit a temperature of
body during the period of watching analogous
to that which they manifest in the heat of the
summer season during sleep. And this is pre-
cisely what happens. M. de Saissy paid par-
ticular attention to the state of these animals
at intervals from the month of August onwards.
On the 6th of August, the temperature of the
air being at 22° c. (72° F.), a dormouse and a
marmot marked 36,° 5 (98° F.), and a hedge-
hog 34° c. (93°, 5 F.) in the axilla. On the
23d September, the external temperature being

672

ANIMAL HEAT.

18° (64°, 5 F.), the temperature of the hedge-
hog was lower by 2° c., that of the marmot by
5°, 25 c., and that of the dormouse by 5°, 5 c.
than it had been at the previous date. This is
a considerable depression, if it be remembered
that the decline in the atmospheric temperature
was by no means considerable; that the air was
in fact still at a point which made it be felt as
warm to the generality of persons. The same
individual animals examined on the 7th of
November, the atmospheric temperature being
7°, presented the following state. The mar-
mot had lost 9°, 25 c., the dormouse 15°, 5 c.,
and the hedge-hog 21°, 25 c. of their respec-
tive temperatures during the month of August,
so that their absolute temperatures were now
as follows: that of the marmot 27° (81° F.),
that of the dormouse 21° (70° F.), and that of
the hedge-hog 13°, 75 c. (57° F.). Here, there-
fore, we have several warm-blooded animals
which in autumn approach very closely to the
cold-blooded tribes with regard to their calorific
power.

If they be next observed during the period
of sleep, the relationship will be observed if
possible in a more striking degree. If, during
the state of watching, they suffer such a loss of
temperature as has been specified with the
gradual decline of the temperature of the year,
they will certainly suffer still more remarkable
changes during the state of sleep, in conformity
with the principles already fully developed.
The sleep of these animals will also become
longer and deeper in proportion as the nervous
system loses its power, under the influence of
the external cold, a loss which will be mani-
fested by a farther retardation in the motions of
circulation and respiration. But what is the
increasing weakness of the nervous system
during sleep but a more or less marked state
of torpor ? The same degree of cold con-
tinuing, or the degree of cold becoming gra-
dually greater, the disproportion as regards the
animal will increase also, and will necessarily
attain a term at which the torpor during
sleep will become lethargic. If the external
temperature goes on declining, and attains a
point at which it becomes dangerous to the life
of the creature, the cold, within certain limits,
ought to have the power of withdrawing the
animal from its state of lethargy. The excite-
ment which appertains to the waking period,
by accelerating the motions of circulation and
of respiration, will then cause the temperature
of the body to rise. But if the external tem-
perature does not become more favourable, or
if the animal finds no means of abstracting
itself from its influence, it has not sufficient
resource within itself and must perish.

We have seen above that the changes in the
seasons produced great modifications in the
constitution of warm-blooded animals in gene-
ral. But it were difficult to imagine any greater
or more striking than those presented to us by
the species which we have just named, which
belong to the family of hybernating animals;
changes which arise from their passing the
winter months in a state of lethargy. When

these animals are recalled from this state to-
wards the end of autumn, and during the
course of the winter, they may seem to resume
the characters which distinguish the vitality of
warm-blooded animals in general, but they are
in a very different state at this epoch from what
they are in summer. Their constitution has
un iergone important changes, which it is
necessary to examine and appreciate exactly.
These changes are inversely as those which the
most perfectly constituted warm-blooded ani-
mals experience. These, under the influence
of the increasing cold of autumn arid winter,
acquire new vigour, and their faculty of pro-
ducing heat increases in consequence. Those,
on the contrary, naturally much less energetic
even at the most favourable period of the year,
require to be excited and supported by the
high temperature of the summer or warmer
months, to permit them to exhibit all their
activity and strength. It is in the warm season
of the year that these animals have the greatest
degree of energy — energy which has a certain
duration even after the external conditions
which have developed it have ceased to operate ;
for they have been as it were tempered by the
continuity of favourable circumstances, espe-
cially of the high atmospheric temperature.
This is the reason why they are so slightly
affected by the diurnal variations of the warm
season of the year; and even when this begins
to wane, and they are no longer stimulated by
the temperature proper to summer, they find
sufficient energy in the store accumulated, as
it were, during the fine season to enable them
to resist for a time and to a certain extent the
unfavourable influences with which they begin
to be surrounded. These continuing, however,
and even increasing, they gradually yield to
their influence, and sink lethargic, till revived
by the return of spring with its milder tempe-
rature. Their languor even augments not only
with a progressively lower degree of atmospheric
temperature, but with the persistence of a
degree which in itself is not by any means
excessive.

These hybernating animals, whilst they pre-
sent the structure of the warm-blooded tribes
in general, still approach in a very remarkable
degree to the cold-blooded tribes in their
defective energy, or their indifferent powers of
reaction. This is to be regarded as the prin-
cipal source of the phenomena they exhibit in
the current of the year, phenomena which
are unknown among the more perfectly con-
stituted warm-blooded animals, but which are
absolutely of the same nature as those presented
by the cold-blooded Vertebrata in the same
circumstances, and which only differ in degree.
This analogy or resemblance in the phenomena
appears to arise from analogy not of structure
but of constitution. Very opposite organiza-
tions may have analogous constitutions ; cold-
blooded animals for example present the
greatest diversities of structure, and all are
affected and bear themselves in the same man-
ner under similar circumstances in very many
respects. They have thus a common constitu-

ANIMAL HEAT.

673

tion which characterizes them, the fundamental
principle or distinguishing feature of which is
a defect of energy, or of power of reaction.
This principle", so simple in itself, artd which
is but the true expression of the various facts
reduced to unity, renders plain and obvious
much that otherwise appears anomalous or
contradictory. In studying the phenomena of
animal heat under new relations, we shall find
the confirmation of what precedes.

OF THE SYSTEM UPON WHICH THE EXTERNAL
TEMPERATURE ACTS PRIMARILY AND PRIN-
CIPALLY.

Our sensations admonish us that it is the
nervous system that is acted upon primarily and
principally by changes of external temperature.
In the first place the impression is felt instan-
taneously ; in the second place the intensity of
the sensation is in relation with the degree of
external heat or cold ; in the third place the im-
pression is not limited to the various degrees of
the corresponding sensation of heat or cold ; it
extends to the other faculties of the nervous
system, increasing or diminishing the general
or special sensibility ; in the fourth place it acts
powerfully in increasing or diminishing the
activity of the muscular system, principally
through the medium of the nervous system.

Influence of temperature on the vitality of

cold-blooded animals.

If the functions of respiration and general
circulation be destroyed by the excision of the
lungs and heart of a cold-blooded animal, of
one of the Batrachia for example, life may still
continue for a time. Of the three principal
systems of the economy the only one then left
untouched is the nervous ; so that the animal
may be viewed as living almost exclusively by
the agency of this system. If several animals in
this condition be plunged in water deprived of
air, they will live in it different spaces of time
according to the degree of its temperature,
the extremes compatible with their existence
being zero and 40 c. It is towards the
inferior limit, zero, that they live the longest.
Towards the upper limit they die almost im-
mediately. Temperature, consequently, pre-
sents in the scale of variations just mentioned
very remarkable relations with the vitality of
these animals. Towards the lower limit or that
of melting ice, it is obviously most favourable to
life; towards the upper limit, it is most inimical
to life, extinguishing it almost immediately.
Here it is impossible to mistake the system
upon which the variety of temperature exerts
its first and principal effects — the nervous
system.

If respiration only be annihilated by
plunging these creatures under water deprived
of air, the temperature of which is caused to
vary as above, they will be found to present the
same phenomena according to the degree of
the heat or cold, but in a more striking
manner. Temperature in this case has the
same kind of influence, but the effects are more
manifest, from the circulation of the venous
blood prolonging life at every degree short of

VOL. II.

the one at the upper limit of the scate, at which
life is extinguished quite as suddenly as in the
former instance.

Such are the direct and instantaneous effects
of temperature upon the vitality of cold-
blooded animals. But there are others which
flow from its successive agency, during a con-
siderable length of time. If the series of ex-
periments just quoted be made in summer,
and the different lengths of life at different
degrees of temperature of the frogs immersed
in water be noted, (between the limits which we
have pointed out above,) and the same expe-
riments be repeated in autumn, the length or
tenacity of life manifested by the animals will
be much greater at the same degrees of tem-
perature— they will in general be found to live
twice as long now as they did in summer, at
corresponding and equal temperatures of the
medium in which they are immersed. The
depression of atmospheric temperature in the
autumn has modified their constitution, and
actually increased their vitality, precisely in
the manner indicated above. The slight
effects of each successive fall in the general
temperature have accumulated in the constitu-
tion so as to render their vitality or tenacity of
life much greater, a fact which is made abun-
dantly manifest by the faculty of the animals
to remain for a much longer time immersed in
water without breathing than they could have
done in summer. If a third series of experi-
ments of the same description be made in
winter, the tenacity of life will be found to
have increased in a very high degree. At the
same degree of temperature frogs will be found
to live immersed in water deprived of its air
at least twice as long in winter as they could
have done in autumn. The same cause — the
depression of the atmospheric temperature —
has continued to act with greater intensity
and for a longer period, and the constitution,
gradually modified by greater and longer con-
tinued cold, has acquired greater tenacity of
life.

The opposite effect takes place with the
successive rises of the temperature from that of
winter to that of summer ; so that among cold-
blooded animals the maximum of vitality,
i. e. tenacity of life, corresponds to the depth
of winter, the minimum to the height of sum-
mer. The slight and from moment to moment
inappreciable effects produced by the external
temperature, whether tending to increase or to
diminish the vitality, accumulate with their
repetition through the period of each season,
and produce a corresponding change in the con-
stitution with regard to tenacity of life. These
accumulated effects of the different portions of
the year constitute the influence of the seasons
on the constitution with respect to many of the
most important relations of life. The first of
these we have just examined cursorily — that is,
the faculty of living in air according to the
influence of the actual temperature, or of that
of the past temperature, in other words the
season that has immediately preceded. The
second of these fundamental relations consists
in the various proportions of air necessary to

2 Y

674

ANIMAL HEAT.

the maintenance of life according to their re-
lations with the temperature. We have seen
that it is at the minimum of temperature that
the cold-blooded animals possess the greatest
tenacity of life, as regards the most essential
relation, in other words they are in the con-
dition the most favourable to enable them to
do without air ; at this point they are in a state
to live for the longest time without breathing.
It is obvious that here they must require less
air than under any other circumstances ; they
must necessarily require so much the less, as
their life will continue longer here than under
any other circumstances without any access of
air at all. It is, however, essential to appre-
ciate duly this fundamental relation, namely,
that at the lower limit of the scale of tempera-
ture mentioned, cold-blooded animals require
less air to live, and what is more, they con-
sume less air than under any other circum-
stances, and are even incapacitated from con-
suming more than they do. The minimum
temperature of this scale consequently is an
ind^x of the maximum of vitality or tenacity
of life, and at the same time of the minimum
of respiration. In the same proportion as the
temperature rises, the vitality or tenacity of
life declines, which makes it necessary that
this declension should be compensated by a
corresponding increase in their relation with the
air, in order that the vivifying influence of
this fluid may neutralize the deleterious effects
of the increase of heat. And this is what
actually happens. With the rise in tempe-
rature the sphere of activity of the respiration
extends, and the vivifying influence of the air,
which increases with the quantity of the fluid
consumed, compensates the successive decre-
ments in vitality or tenacity of life, dependent
on successive increments of temperature. We
shall therefore express in a very few words this
fundamental relation between the tempera-
ture of the air and the maintenance of life
among the invertebrate series of animals, — a
relation entirely deduced from direct experi-
ment, which we can but refer to here, but
which we shall lay before our readers with all
the requisite details in our article on RESPIRA-
TION. The rise of temperature in the scale
from zero to 40 c. exerts upon the nervous
system of cold-blooded animals an action the
tendency of which is to diminish its vitality ;
the air, on the contrary, exerts a vivifying in-
fluence on this system. It becomes necessary,
therefore, to the maintenance of life that their
respective relations with the economy be such
that their effects compensate or counterbalance
each other.

The principle relative to the influence of
temperature on the vitality of cold-blooded
animals just laid down, is applicable in every
particular to the changes experienced and the
phenomena presented by the hybernating tribes
among the warm-blooded series of animals.
Their vitality changes with the wane of the year,
i. e. under the influence of prolonged exposure
to cold, in the same manner They are then in
a condition to exist with a supply of air by so
much the less as this influence has been more

intense and more protracted ; and precisely as
the cold-blooded tribes, if entirely deprived of
air in winter, they will live for a much longer
time in this deleterious position than they
would have done in summer.

Influence of temperature on the vitality of
warm-blooded animals and of man in the
states of health and disease.

These principles and considerations lead us
to examine what happens among warm-blooded
animals in the same circumstances. There being
great and manifold analogies between them and
the preceding tribe of animals, there must also
be some community in the application of the
principles laid down; but as they also differ
in many important respects, this application
must be correspondingly restricted. In the
first place, then, there is complete analogy
between the one and the other with regard to
the influence of the superior thermal limit on
the vitality of the nervous system. To seize
the analogy properly, it is however necessary
to regard the temperature which modifies this
system in each series, from a point of view that
is common to both. Whether the temperature
proceeds from without or from within, we may
presume that it will influence or modify the
nervous system in the same manner, if not
to the same degree, inasmuch as this system
presents differences. Warm-blooded animals
having in general a high temperature at all
seasons of the year, they must be compared
in this respect with cold-blooded animals in
the height of summer. On the one hand, heat
within certain limits tends to increase sensibi-
lity and motility ; warm-blooded animals,
therefore, with a few exceptions, which always
present a high temperature, constantly exhibit
also, with a few exceptions, a high degree of
sensibility and motility. The same thing can
only be said of the cold-blooded tribes during
the continuance of the warm weather. On the
other hand, again, high temperature tends to
lessen the vitality proper to the nervous system,
or the faculty of living without the agency of
the ordinary stimuli. This is also the reason
why, if respiration be interrupted among warm-
blooded animals at all times, and among cold-
blooded animals during the warmer seasons of
the year, they all perish alike speedily or nearly
so. The difference in the time that elapses
before life is extinct still depends on, or is in
relation with, the difference of temperature.
For in the hotter season of the year, cold-
blooded animals never attain the temperature of
the warm-blooded tribes, even in the most
burning climates of the globe. Their nervous
system will consequently have a higher degree
of vitality in the sense already indicated ; that
is to say, they will not perish so promptly in
summer under deprivation of air ; but if they
be immersed in water at the mean tempera-
ture of warm-blooded animals generally, which
is about 40° c. (104° F.), they will die as sud-
denly— .(at least this is the case with those of
small size upon which the experiment has been
made) — as the warm-blooded Vertebrata when
deprived of the contact of air.

ANIMAL HEAT.

67-5

The analogy on either hand consists in the
effects of temperature. But the differences
that must necessarily occur between natures
that vary in so many other respects are espe-
cially encountered in the dissimilar effects of
cold. Here we observe a general compensa-
tion which distinguishes in the most marked
manner the Vertebrata having a constant or all
but a constant temperature, from the hyber-
nating tribes or Vertebrata whose temperature
varies, and the cold-blooded series generally.
The relation of cold, or of a low temperature
relatively to the standard of the more perfect
beings of creation, is one of essential impor-
tance, and requiring our most careful investi-
gation.

Cold, as has been said, tends to diminish
sensibility and motility; but cold itself is per-
ceived by causing a diminution of the general
sensibility ; among animals of superior organi-
zation it even acts indirectly as a stimulus :
the blood flows into the parts that had" been
chilled, if their temperature has not fallen
too low, for then all sensibility is extinguished
and reaction never occurs. The afflux of
blood to the external parts is manifested by
the increased redness ; and the skin becomes
red in proportion as the parts it covers are
susceptible of acquiring a high temperature,
such as the hand. We have shown that the
consequence of the afflux of blood is an in-
crease of temperature which tends to counter-
balance the effects of the refrigeration. The
compensation, however, is not perfect. For
in winter the temperature continues above that
of summer, although there is a greater pro-
duction of heat in winter than there is in
summer, as we have shown above.

The constitution of the Vertebrata having a
nearly constant temperature differs essentially
in the power of reaction it possesses ; a power
which cannot better be expressed than by the
word energy, and which must necessarily be
referred to the nervous system. The power of
reaction under the influence of cold is exhi-
bited in two modes : the first is that which has
just been mentioned, in which the stimulus of
the cold calls the blood into the capillaries of
the surface, without exciting any kind of vio-
lent motions in the circulating and respiratory
systems ; the second consists essentially in
this last kind of excitement. The sharpness of
the cold stimulates the respiratory motions,
which become accelerated, and the quickening
of the motions of the heart follows or accom-
panies those of the lungs. These two modes
of reaction must be viewed as two degrees of
the same power : 1st, an afflux of the blood to
the capillary vessels ; 2d, acceleration of the
motions of the thorax and heart. There is,
however, between these two processes a diffe-
rence which it is of the greatest conse-
quence clearly to understand. The first, so
long as it remains within certain and suitable
limits, is a reaction that maintains the eco-
nomy in a state of health. The second tends
to produce salutary effects, but becoming ex-
cessive it brings the body into a state of disease.
The first is sufficient to enable those creatures

whose system is energetic to resist the effects
of rigorous cold, by preserving their general
activity and the normal state of their functions.
The second is the resource of those animals,
which, although of the same species, are so
constituted that the energy of the nervous sys-
tem is less than in the former. This is what
occurs universally in very early life. It is a
reaction the tendency of which is salutary, but
which is not the less on this account the
index and essence of a proper pathological
state. It is one of the cases in which the vis
medicatrix nature is peculiarly and most
strikingly manifested. This position is made
singularly evident by the following experi-
ment : — when a young bird, bare, or but scan-
tily covered with feathers, is taken from the
nest, and exposed to the open air, even in the
summer season, its respiration will be seen to
be accelerated in the ratio of the cold it expe-
riences. It is peculiarly worthy of remark
that this salutary reaction, taking place under
the influence of the nervous system, acting, in
the case quoted, independently of the will, is
in a great measure the same as that which we
bring into play by means of the will to com-
bat the same evil. When in health, for instance,
we are exposed to and feel the impression of
cold severely, and have no resource but in our-
selves, we begin immediately to take exercise,
and move about; and if we do this with sufficient
vigour, the motions of respiration and circula-
tion are very soon increased in rate, and
our heat returns ; it being always understood
that the external cold is not at too rigorous
a degree. From what precedes, we are in a
state to appreciate the part which each func-
tion has in causing the developement of heat by
exercise. The experiments of Messrs. Bec-
querel and Breschet, referred to in an early
part of this paper, have proved that the con-
traction of the voluntary muscles is accom-
panied by the evolution of caloric, and that
the heat increases by a succession of muscular
contractions. The first source of the heat
evolved in exercise, therefore, lies in the con-
tractions of the muscles, that is, in the volun-
tary motions. These, vigorously called into
play, are followed by increased rapidity in the
action of the muscles of respiration, and of
the central muscle of circulation, the heart;
and these, by the increased energy they impart
to the functions over which they preside, cause
an increase in the temperature in conformity
with the general principles already laid down.
It is well to follow the effects of exercise in the
various modifications under the influence of
cold. They produce phenomena which extend
farther than the state of health, and which ap-
pear in other conditions and circumstances
from analogous reasons. Exercise, according
to its degree and the degree of temperature
of the external air, is adequate not only to
compensate a chill, and to restore the body to
its pristine temperature in every part, but even
to do more than this. If the exercise has been
sufficiently prolonged, but not been excessive,
it may be suspended ; and the body, now re-
stored by its means to its temperature, will be
2 Y 2

670

ANIMAL HEAT.

apt to retain it longer than it had done when
exposed to cold without any preparation of the
kind implied; it will resist impressions of cold
longer after exercise than it would after a state
of perfect quiescence ; the nervous system
has acquired new energy ; the economy is in
a condition to react with greater effect than
when depending on the process just described,
that, namely, which takes place independently
of the agency of the will. The repetition of
the effects that follow exercise taken at due in-
tervals, hardens the frame to such a degree that
the body at length acquires the power, by
means of the insensible and involuntary reac-
tion alone, to resist degrees of cold which it
could not have borne without the violent and
voluntarily induced reaction of active muscular
exertion.

The different states of the body in the cir-
cumstances just referred to deserve special
attention, because they are reproduced in
others, where the cause not being apparent
they seem to be spontaneous, though they are
in fact, as we shall have occasion to see, under
the influence of an analogous cause. We sup-
pose that on the first exposure to cold during
rest, the reaction from the afflux of blood to
the capillaries is slight, and that the cold is
even sufficiently intense to produce an opposite
effect, that is, paleness of the part chilled.
To this symptom of the action of cold, shiver-
ing is superadded in various degrees of inten-
sity. If recourse be now had to exercise, this
state will last for a period long in proportion
to its intensity, until violent and prolonged mo-
tion have restored the temperature. If the
exercise be continued, the heat increases, and
even rises above its degree at starting ; in this
case it first restores the proper heat of the skin,
and then causes this tegument to assume a red
colour, which may become extremely intense.
To this second state succeeds a third, in which
the skin, which had hitherto been dry and un-
perspiring, becomes soft and finally bedewed
with moisture. Here, then, we have three
different states induced under the influence of
cold acting at first without opposition on the
part of the system, and then combated by
powerful and voluntary reaction. First, we
have coldness, paleness, and shivering ; secondly,
heat and redness; thirdly, moisture of the skin
and sweating. In making the application
here of what has been said above upon the
repetition of these acts, we perceive that at the
same degree of external temperature the effects
which at first, and under other circumstances,
would follow the impression of such a degree
of cold, may cease to be felt. This happens
from the constitution having improved under
the actions and their effects, which have been
detailed, and that it is in a state, with the
assistance of its own inherent powers of insen-
sible and involuntary reaction, to resist refrige-
ration. But do we not, when we strengthen
the constitution to such a pitch as enables it to
resist an influence which was a cause of incon-
venience to it previously, cure it of an infir-
mity ? It is obvious from what precedes that
the temperature of the body may be indiffe-

rently affected, either by a great fall in that of
the air, or by an insufficient production of heat.
The temperature of the body tends to sink
equally when, producing a great deal of heat,
it is exposed to severe cold, or when, producing
little heat, it is exposed to a moderate warmth.
In either case the effects upon the economy
will be analogous without being identical. In
each case there will be a keen sense of cold
according to the depression of the external
temperature on the one hand, or the slightness
of the evolution of heat on the other. In the
latter case the insensible reaction will be ex-
tremely limited, as well as the voluntary reac-
tion, on account of the deficient energy. But
there are still resources within the economy. It
is then that the involuntary and violent reaction
of which we have already spoken takes place.
The circulation and the respiration increase in
rapidity spontaneously. In the case which we
havagust supposed, there will be certain series
of phenomena, analogous to those we have
described as occurring in the instance of a
strong individual exposed to the influence of
severe cold, who surfers from it at first, and
subsequently opposes and vanquishes it by
means of a violent and voluntarily superinduced
reaction. When the faculty of engendering
heat sinks to a certain term, there will be not
only a vivid sensation of cold even in summer,
but all the other consequences of exposure to a
low temperature, such as paleness, shivering,
&c.; by-and-by the involuntary reaction will
not fail to take place; the respiration and
circulation are accelerated, and end by restoring
the temperature, if the lesion of the calorific
power have not been too extensive, the skin
being first hot and dry, and subsequently hot
and moist. Here, consequently, we have the
three periods precisely as in the case previously
described : 1st, coldness, pallor, and shivering ;
2d, acceleration of respiration and circula-
tion, accompanied in the second period by dry
heat, and in the third by sweating. There is
therefore the strongest analogy in the two
cases. They resemble one another in the cha-
racter of the phenomena, and the order of
their succession. This is so obvious as merely
to require mention ; there can be no occasion
for more particular illustration. They have
also the strictest relationship in their causes,
without these, however, being identical. In the
first case the individual produces a great deal
of heat, but he cannot engender enough by the
ordinary and insensible reaction, in conse-
quence of which he has recourse to the violent
and voluntary reaction, which soon produces
the desired effect. In the second, the indivi-
dual produces little heat, and the economy
may suffer from this diminution of the calorific
faculty to the extent of finding itself incapable of
restoring a sufficient degree of heat by means of
a violent and voluntary reaction. The violent
and involuntary reaction then succeeds, and pro-
duces all the effects of that which is put into
play under the empire of the will. Nor is the
resemblance limited to immediate results. It
further extends to the remote and definitive
effect. For in either case the violent effort

ANIMAL HEAT.

677

ceases after a certain interval of variable extent,
according to various circumstances ; and
a state of tranquillity comes on in which the
body has recovered the faculty of engendering
by the ordinary means the quantity of heat ne-
cessary to the comfortable existence of the in-
dividual. After this the repetition with greater
or less frequency of the same acts ends by
restoring the calorific function to the state in
which insensible reaction suffices to maintain
it in its sufficiency. In the first case it is a
strong individual able to make the voluntary
and energetic efforts required to remedy the
inconvenience he suffers. In the other instance
it is an individual who has not the strength
requisite to make such efforts. In this case
nature supplies the deficiency by exciting
directly the motions of circulation and respira-
tion by the painful impression of cold. Al-
though the condition of the first be the state
of health, and that of the second properly a
morbid state, they nevertheless have many
relations in common, which differ princi-
pally in degree. Does not the robust indivi-
dual experience an inconvenience for which he
finds a remedy in violent and repeated efforts?
However robust he may be under ordinary cir-
cumstances, in the extraordinary condition in
which he is placed the usual vital processes
no longer suffice him. He must have recourse
to violent means which disturb the economy ;
and by a repetition of the same efforts at diffe-
rent periods, that is to say, in fits or paroxysms,
he ends by so far fortifying himelf as to be able to
do without them. Is not this tantamount to
remedying a relative infirmity of constitution ?
Let its degree increase but a little, and the
infirmity becomes disease. This parallel is not
founded on vague and superficial resemblances,
but on determinate and fundamental relations.
There is not one essential point in the compari-
son which does not rest on the result of direct
experiments, most of which have been quoted
in preceding parts of this article. What must
be done to justify the similitude of these
two states ? With regard to the state of health
the connexion of phenomena having reference
to the hygienic and voluntary reaction is well
known. With reference to the relation between
the symptoms in the morbid state and the
morbid reaction, it remains to be proved that
under circumstances where there is but slight
production of heat, the feeling of cold may
induce acceleration in the respiratory and circu-
latory motions. Now it has-been established by
experiments already quoted, that there is reac-
tion of this precise kind in such circumstances.
We have seen, for instance, that when a bird,
naked or scantily covered with feathers, is
taken from the nest and exposed to the air
even in summer, it speedily begins to shiver,
and to exhibit a reaction in accelerated motions
of respiration, which is followed by, and indeed
implies increased rapidity in the motions of
the heart and current of the blood. It were
also proper to show that the cold state may, by
means of the violent and involuntary reaction,
induce the restoration of heat. This is also

susceptible of proof by means of direct expe-
riment. To this end an individual (a young
bird from the nest) must be chosen of such
an age that the temperature will not be apt to
fall too low on exposure to the air. If the
choice have been fortunate, it will be found that
the temperature sinks in the first instance, and
then rises, so that it may even surpass the de-
gree it showed at first, under the influence of
the reaction occasioned by the acceleration of
the motions of respiration and circulation.
The proof here is, therefore, extremely satis-
factory. A creature in a state of health is taken
and placed in circumstances in which the same
essential symptoms are produced in the same
order as in the morbid state which we have
described. It can scarcely be necessary to say
that the morbid state which we have described
in man is that of simple intermittent fever.
Not only in the beginning of this disease is
there a feeling of cold, but recent accurate ob-
servations have shown, by means of the ther-
mometer, that there is actual refrigeration.
There is, therefore, lesion of the calorific func-
tion in the sense previously indicated, that is,
there is decrease in the power to produce heat.
Subsequently the temperature rises whilst
there is still more or less of the sensation of
cold remaining ; but this only happens by vir-
tue of a general disposition of the nervous
system. The same thing, in fact, occurs in a
state of perfect health ; when the body has for
some time been exposed to severe cold, the
sensation continues for a certain interval after
it has been restored to the normal temperature.
It is of little consequence, as regards the sub-
ject which engages our attention, that there are
some intermittent fevers which do not exhibit
the phenomena of temperature that have been
described. We are only interested in proving
that some do occur which present them all, — a
fact that has been demonstrated by the best
authorities.

There is consequently in these cases a lesion
of the calorific function, a lesion of which the
essence consists in a diminution of the faculty
of producing heat. In a constitution capable of
re-acting by the acceleration of the respiration
and circulation, we may observe upon this occa-
sion two principal modifications of the morbid
state, which both depend on the same cause,
but which differ in degree. The first is that
described in which the reaction suffices to
restore the calorific power to the degree com-
patible with health after one or more fits or
paroxysms. Writh regard to the second, the
diminution of the function of calorification may
be so great, that the reaction may prove in-
adequate to restore it, not only permanently
but even momentarily. There are in fact
diseases of this kind ; there are many regular
intermittent fevers that have no tendency to
spontaneous cure ; there is also one particular
form of the disease which proves speedily fatal
without the intervention of art. This is that
form of intermittent which is known at Home
especially under the name of \\\ejebbrc afgidtt,
or cold fever. It often happens that the patient,

678

ANIMAL HEAT.

unless suitably treated, dies in the cold stage of
the second or third paroxysm ; sometimes he
will even perish in the first.

It is easy to produce at will the essential
symptoms of these affections even in their most
formidable shapes, in animals in a state of
health. All the young birds, for example,
belonging to the group of those which at their
birth have the weaker calorific powers, can be
made to exhibit the phenomena in question. If,
at the period of their exclusion or shortly after
this, they be taken out of the nest, we have
seen that they lose heat rapidly even in the
summer season; and we perceive that any
reaction of which they are capable by the
acceleration of their respiratory and circulatory
motions avails them nothing ; their tempera-
ture sinks in spite of this, till all reaction
ceases by the increasing and now benumbing
influence of the cold, so that they speedily
perish. In these two extreme cases of dimin-
ished production of heat, there is similarity in
the symptoms which ensue, with this difference,
that in we algid intermittent there is lesion or a
morbid state of the calorific faculty ; whilst in
the other case the scanty production of heat is
a normal condition in relation with the age of
the subject. In the first, the constitution is
seriously altered ; it must be restored or other-
wise the individual dies; in the second, there
is no alteration of any kind; the individual
only requires to be placed in circumstances
favourable to the normal manifestation of the
function to be restored. In the one the
lesion is so great that there is no resource in
nature abandoned to her own efforts ; art must
interfere. In the other, nature provides against
the scanty production of caloric in giving to
parents the instinct to warm their young by the
heat of their own bodies, &c.

We have seen that cold, when not of too
great intensity, tended to strengthen the body
by increasing the faculty of producing heat;
and farther, that with the progressive rise of
the temperature in spring and summer the
energy of this faculty diminished. This is
what takes place with regard to those constitu-
tions that are in the most favourable relation
with the climate. Let us now examine the
nature of those constitutions that do not adapt
themselves thoroughly to the changes of the
seasons, and see what the consequences are with
regard to them. Let us begin with the rela-
tion of these to the cold season of the year.
It might be presumed a priori that those con-
stitutions that have a very limited capacity of
engendering heat will not accommodate them-
selves well to the cold of winter. Their
limited powers of producing heat will not ena-
ble them to repair the continually increasing
loss of it arising from the depression of the
external temperature. They consequently suffer
in a greater or less degree from cold, perhaps
not to any great extent in the first instance,
as we shall have occasion to explain by-and-
by, but still in some measure ; and there are
certain degrees of uneasiness and inconvenience
that may be regarded as being still within the

limits of health. There is even a certain, and
that a pretty wide latitude in which the body
may vary without trespassing on the line of
disease. The uneasiness may only be ex-
perienced from time to time, and not even be
always very manifestly referable to its proper
cause. In other words the sensation may be
something quite different from that ordinarily
induced by cold; just as it sometimes happens
that among weak constitutions the necessity of
taking food is not always proclaimed by the
feeling of hunger, but occasionally by some
other distressing or painful sensation, with re-
gard to the true nature of which experience
alone can enlighten us. In such a low state of
the calorific power, the faculty seems to lose
strength still further, owing to the simple per-
sistence of the same degree of cold, and still
more from the ulterior depression of the tem-
perature, in the manner we have seen when
speaking of hybernating animals. This dimi-
nution in the temperature of the air sometimes
occasions among weakly subjects morbid re-
action, the principal features of which have
already been explained. From all that pre-
cedes, the constitutions that will be the most apt
to suffer from exposure to cold will be those of
the earliest times of life observed in man and
the warm-blooded tribes generally, since it is
at this epoch that they produce the least heat;
and as a corollary from this, we should infer
that the mortality in early life ought to be
greater during the winter season in this and
other countries similarly circumstanced. It
became a matter of peculiar interest to verify
this inference from the experiments and
reasonings of which we have just rendered an
account. Messrs. Villerme and Milne Edwards
accordingly undertook the necessary inquiries,
entering upon extensive statistical researches
with reference to the mortality of children in
the different seasons of the year in France, and
found that the mortality of infants from their birth
to the age of three months was generally the
greatest in those departments of which the
winters were the most severe. . For a similar
reason, the natives of very warm climates who
visit countries whose winters are excessively
cold, run great risks of not being able to pro-
duce heat enough to compensate the loss they
sustain from exposure to the low atmospheric
changes, and thus of becoming obnoxious to
disease and death in consequence. Those that
have elasticity enough of constitution to meet
this unwonted demand upon their calorific
powers, experience an increase in the energy of
the functions upon(which the production of heat
depends, by which they are brought into har-
mony with the climate. Others who are less
robustly constituted complain loudly of the
cold, languish, and finally perish if they do not
find means of escaping from the destructive
tendency of the cold.

What happens, in as far as these different con-
stitutions are concerned, when the change of
season is the opposite of that we have just dis-
cussed ? when the progress is from the colder
to the hotter period of the year ? The constitu-

ANIMAL HEAT.

679

lions that have just been particularly mentioned,
it is obvious, will find themselves benefited by
the change ; they are continually supplied with
larger proportions of heat of which they were
especially in want. But robust constitutions,
in which the calorific faculty is largely deve-
loped, will they not be in an opposite position,
unless the energy of the faculty in question
diminishes in proportion as the external tem-
perature increases ? This in fact is what of
necessity happens to those in whom the
power of accommodation is defective. For
when the calorific faculty continues in full
force, when the temperature of the surrounding
atmosphere is high, there is an excess of heat
proceeding from within as well as from
without ; and if the body does not suffer in the
first instance, which it is apt to do, it before
long feels the deteriorating influence of this
additional excitement, which thensuperinduces
a series of morbid phenomena of various degrees
of intensity according to circumstances. All
this is observed to occur in the most distinct
manner among the natives of cold climates
who come to reside in very hot countries. The
most robust are even observed to be the most
apt to suffer from the change, and the effect is
so decided, that few escape some derangement
of health, occasioned solely by the influence of
the high temperature. When the affection
appears in the acute form, after recovery,
the new comer is said to be seasoned. The
constitution appears to have suffered a favour-
able change, which consists essentially in
a decrease of the faculty to produce heat. In
fact it is often only by a process of this kind
that the calorific power can be brought into
harmony with the new circumstances in which
it is placed.

Something of the same kind even takes
place in the constitutions of the inhabitants of
the countries which have two very different
temperatures during the two halves of the year.
Here, however, the change of constitution ge-
nerally passes insensibly or nearly so, the
transition being both less in itself, and the
natives being accustomed to the difference.
Let us just remark that we have here another
instance of the vis medicatrix nature, the ten-
dency of which at all events is salutary, but of
which the violence of effect by exceeding the
proper limit frequently becomes fatal. \Ve
even perceive here that nature has two pro-
cesses at her command, by which she adapts us
to changes of external circumstances ; the one
is gradual and insensible, the other is sudden
and violent.

From repeated observation, and from experi-
ments upon the effects of exposure to high tem-
peratures, it is easy to infer the general charac-
ter of the disease in its simplest form, which the
natives of cold climates will be likely to con-
tract in hot countries. As a high temperature
of the air accelerates the breathing and excites
the circulation, it may arouse these functions to
such a pitch, that the condition becomes truly
pathological, and the disease which results is
continued fever with excessive heat of surface in

those countries where the external conditions
are subject to little variety.

There are other phenomena accompanying
changes of climate that are referable rather to the
state of health than to any morbid condition that
bears upon the sensations. It is a general re-
mark that natives of the warmer regions of the
earth, of a good natural constitution, when they
visit countries within the temperate zone, suffer
little from the effects of cold the first winter ;
on the contrary, they seem to live very much at
their ease, except in extreme cases. Let us see
if we can explain this fact with the assistance
of the principles established above. If the
natives of warmer climates come during the
summer to temperate countries, they experience
a change of no great amount indeed, and
which, in the generality of cases, is not obvious.
The heat grows less and less intense, declining
gradually; freshness or coolness succeeds; then
comes moderate, and at last severe cold. Well-
constituted individuals, therefore, and they
may be assumed as the majority, will experi-
ence the general influence of a gradual cooling
process ; that is to say, their faculty of produ-
cing heat will increase, whence will result a
feeling of warmth and of comfort. But this
faculty has its limits of increase, which in fact
lie within narrower bounds than in the case of
well-constituted natives of temperate climates.
They are consequently apt at length to fall
short of the mark, and so to remain, in regard
to calorification, under the standard necessary
to the economy. Whenever the progression
of which we have spoken ceases, which hap-
pens in the course of the second winter, these
individuals begin to experience the uneasiness
which results from its deficiency. It is easy to
confirm and render manifest the justice of the
above deduction by means of a simple yet
curious experiment. If a person having warm
hands will keep one plunged for some time in
water near the freezing point, it becomes chilled
of course, but reaction will be observed soon to
take place, and the hand will become red. If it
be now taken out of the water and wiped dry,
the individual being all the while in a cool at-
mosphere, at 10° or 12° c., the hand will by-aud-
bv begin to glow, and the feeling in it will be
that of a temperature considerably above the
heat of the other hand ; — judging by the feeling
alone the hand seems hotter than the other; tried
by the thermometer however, it will be found
to be cooler; or if it be applied to the other, it
will at once be discovered to be below the tem-
perature of the hand that was not chilled.

Let us follow the effects upon common sen-
sation produced by a change of climate of an
opposite kind. When the inhabitants of cold
countries visit the hotter regions of the globe,
how do they contrive to endure the heat in the
first instance? Experience has often shown that
when they are of the same race, they endure it
at first with even greater ease than the natives
themselves, and that they brave with greater
hardihood and less suffering the utmost ardour
of the sun. This capacity of resistance, how-
ever, has its term, and those who possess it

680

ANIMAL HEAT.

gradually lose it, as has been shown in a
former passage of this article. The native of
the colder clime is more robust, and his nervous
system, less impressible, resists painful sensa-
tions in a greater degree, and is not over-
whelmed by the first effects of noxious influ-
ences. This conclusion is also susceptible of
demonstration by the way of direct experiment.
If during summer a frog be completely im-
mersed in a small quantity of water at the ordi-
nary temperature of this season of the year,
and the same experiment be repeated during
winter with water heated to the summer pitch,
the animal will live much longer in the latter
than in the former instance. The nervous sys-
tem of the animal, by the continued action of
the cold of the autumn and winter, has been
rendered much more capable of resisting noxi-
ous influences, as we have had occasion to see
already. It is on the same principle that the
Finlander, according to the account of Acerbi,
can endure a bath at a much higher tempera-
ture than it could be borne by a native of a
warm or more temperate climate.

EFFECTS OF VARIOUS OTHER CAUSES OF MODI-
FICATION IN EXTERNAL AGENTS.

The effects of external heat and cold on the
sensations and on the system in general are not
altogether dependent on degrees of temperature.
Even at the same degree atmospheric effects
are often very different, being principally influ-
enced by the state of dryness or moisture, and
by that of motion or rest, of the air. Speaking
generally, media exert modifying influences
other than those comprised in their tempera-
ture upon the phenomena of animal heat. Eva-
poration is a powerful cause of cooling, which
increases in the same measure as the evapora-
tion. In the summer season, consequently,
during a state of the weather in which the
temperature is the same, but the hygrome-
tric condition different, the heat of the body
will be higher in moist than in dry air. In the
same way we observe all the effects of excessive
temperature upon the body to be much more
intense with a moist than with a dry atmo-
sphere. In the climate of northern France orEng-
land it would be impossible to stand a vapour-
bath at a temperature between 40° and 50° c.
(104° to 122° F.) for more than ten or twelve
minutes ; but with a perfectly dry state of the
air it is possible to bear a temperature twice, or
more than twice as high during the same space
of time. M. Delaroche found that he could
not remain in a vapour-bath raised in the
course of eight minutes from 37°,5 to 51°,25c.
(100° to 125° F.) for more than ten minutes
and a half, although the bath fell one degree.
M. Berger was compelled to make his escape
within twelve minutes and a half from a vapour-
bath the temperature of which had risen ra-
pidly from 41°,25 to 53°,75c. (106° to 1 29° F.).
Both of these experimenters felt themselves
become weak and unstable on their legs, and
were affected with vertigo, thirst, &c. The
weakness and thirst continued through the
remainder of the day. But in the course of

Dr. Dobson's experiments, a young man con-
tinued for twenty minutes in a dry-air stove,
the temperature of which was 98°,88 c.
(210° F.), within a degree or two, conse-
quently, of the ordinary boiling temperature
of water. His pulse, which usually beat 75
times in a minute, now beat 164 times.
This, however, is by no means the degree
of heat that can be and that has been en-
dured. M. Berger for five minutes bore a
temperature of 109°,48c.; and Sir Charles
Blagden went still further, having exposed his
body during eight minutes to the contact of
dry air heated up to the extraordinary pitch
of 115°,55 and!27°,7c- (240° and 260° F.).
In assigning 40° or 50° c. (104° or 122° F.)
for the limits of moist temperature that can
be borne by the inhabitants of these coun-
tries, we are perfectly aware that in other lati-
tudes it can be greatly exceeded. Thus Acerbi,
in his journey to the North Cape, informs us
that the Finnish peasantry remain for half an
hour or more in a vapour-bath, the temperature
of which finally rises to 70° and even 75° c.
(158° and 167° F.). We have already given
the reason of this difference of constitution.

Experimental philosophers have not yet tried
the precise comparative cooling effects of dry
air and of watery vapour ; but all are agreed
that the powers of the moist atmosphere are by
far the most considerable. To measure the
comparative effects upon the economy the fol-
lowing experiments were instituted. In equal
spaces, the one filled with air at the point of
extreme humidity, the other with extremely dry
air, were placed young birds of the same age,
which were as yet incapable of maintaining
their temperature at its proper height when
taken out of the nest. It was found that they
lost temperature nearly in the same propor-
tion in the same space of time when the air
was either at the point of extreme humidity
or of great dryness. Therefore moist air tends
to cool at least as much as dry air by evapora-
tion. It cools both by the abstraction of heat
and by its action on the nervous system. Its
action on the nervous system is of a debilitating
nature, and therefore tends to diminish the
power of generating heat. The sensation of
cold was evidently greater in the moist air, as
was shown by the shivering of the animal.
There can be no doubt that the action of
vapour in this case is complicated by a physi-
cal influence in the one instance, and by a pecu-
liar physiological effect on the nervous system
in the other ; for it is well ascertained that water,
as contrasted with air, has a debilitating effect
upon the economy. General experience comes
in support of these results; men have ever
agreed that moist and cold states of the atmo-
sphere and humid and cold climates were more
difficult to be borne than those of an opposite
character. Such climes in fact are in them-
selves extremely insalubrious. By their pecu-
liar effects on the economy they tend greatly to
lessen the power of producing heat, and they
also engender intermittent fevers, among other
morbid conditions. According to the state of

ANIMAL HEAT.

681

the economy and the degree of the external
temperature, watery vapour tends to refrigerate
still more in winter, and to add to the heat in
summer.

The state of the atmosphere in regard to
motion or rest modifies to a great extent the
effects of a given temperature upon the body.
Refrigeration by simple contact increases in
amount with the rate of motion of the air. The
same law holds good in regard to evaporation,
and indeed this process always complicates the
results proceeding from simple contact. The
cause of refrigeration in this case is consequently
double. It is easy, therefore, to imagine how

rerful a cause of cooling a cold wind must
But observation can alone give any ade-
quate idea of the extent of its influence in this
respect. Mr. Fisher, one of the surgeons in
the expedition under the command of Sir
Edward Parry to the Polar Seas, has given us
an account of its extraordinary effects. In the
frozen regions around the arctic circle, the
hardy voyagers under Capt. Sir E. Parry found
that they could stand a cold adequate to freeze
mercury when the air was perfectly calm, much
more easily than a temperature nearly 50° F.
higher when it blew. The air in motion in
this case, therefore, produced a sensation of
cold that was equal to such a depression of
temperature as is indicated by a fall of 50° of
the scale of F. — a most prodigious difference.

Sudden transitions of temperature also exert
a great influence independently of any limits ;
in the first place, because the intenseness of
the sensation of cold or of heat is in propor-
tion to the suddenness of the abstraction, or of
the communication of heat ; and again, be-
cause the faculty of adaptation to different
degrees of external temperature is not acquired
all at once, but is only attained in a certain
lapse of time, and by gradual modifications
in the constitution. We therefore see that
those countries of which the temperature is
very high in the day, but very low in the night,
are subject to diseases that seem to belong
more peculiarly to cold and moist latitudes,
or to marshy lands where malaria prevails.
But the transition from hot to cold is not
limited to the suddenness of the thermal de-
pression ; it extends to the refrigeration by the
action of the wind. This is another among
the many reasons why in the latitudes of Eng-
land, France, &c. spring is a more dangerous
season than autumn. There are, however, cer-
tain cases of sudden transition that are useful
and salutary, as for instance,when the heat of the
body is excessive, and is doing mischief, whe-
ther it be induced by an elevated external
temperature, or proceeds from the violent and
involuntary action of our organs. Then re-
frigeration even of the most sudden kind, pro-
vided it be restrained within proper limits,
becomes beneficial. It is thus that the
affusion of cold water produces such excellent
effects in cases of extreme excitement, and
where the temperature is really above the
natural standard. This process is even to be
regarded as one of the most brilliant tri-
umphs of modern medicine. It is much to

be regretted that recourse is not had to it more
frequently. It is evident that the proper time
for the use of this powerful means is that in
which congestion has not yet passed into ob-
stinate engorgement, that is to say, in the
beginning of the disease, in which by allaying
excitement congestion is diminished. The
favourable moment for using the cold affusion is
that in which the skin is hot and dry, which
is also the period of the highest excitation.
The experiments upon the effects of baths,
quoted above, tend also to show the propriety of
the practice ; in citing these, we mentioned that
the diminution of temperature produced in the
body lasted for hours, and that the reaction
consequent upon the use of the bath did not
carry the temperature higher than the pitch it
possessed at starting. It is obvious that the
effects of the cold affusion are to be derived
from the principles previously established;
since we have referred the production of heat
to two general conditions of the economy,
one of which is the state of the nervous sys-
tem. Now the affusion of cold water acts
directly upon this system. There is another
powerful method of tempering animal heat,
which flows from the other general condition,
upon which the production of heat depends,
viz. the state of the blood. We have seen
above that the respective proportions of the
serous mass of the blood and of its red glo-
bules exert an important influence; that in
the class of vertebrate animals which produce
smaller quantities of heat, the proportion of
the serum was in the inverse ratio of the
faculty of calorification. Whence it follows,
that in cases of excessive heat of body, to
reduce the quantity of red globules would
prove an effectual mode of reducing the tem-
perature. Now this is precisely what is done
by bloodletting. The effect, however, in this
way is not instantaneous. The first influence
of bloodletting is simply to lessen the quan-
tity of the blood, and this is the extent to
which ideas of the influence of the abstraction
of blood are generally confined. There is,
however, a consecutive influence, which is at
the least as important, and which proves much
more lasting. As the person who has been let
blood confines himself at the same time to
low diet, and principally to liquids, it is obvious
that the blood is recruited in its quantity
principally by additions of watery particles,
without any notable or even sensible addition
of globules. The blood is therefore altered
essentially in its constitution; the proportion
of its component fluid and solid elements is
changed, and this in direct proportion to the
extent and frequency of the venesections. The
consequence of this is a diminution of tempe-
rature, unless other causes oppose such an ef-
fect.

Bloodletting, it must be observed, is not the
sole means of accomplishing such a change in
the constitution of the blood. We can pro-
duce a similar effect by exciting one or all of
the secretions which are thrown off by the
body. Secretion is performed at the cost of
the blood, which supplies both of its elements

682

ANIMAL HEAT.

— the solid and the fluid part. The more
the secretion eliminated abounds in solid parts
or matters formed at the cost of the solid
constituents of the blood, the more is the
blood impoverished in these elements — the
more is its mass of globules diminished.
Absorption then begins, as in the preceding
case, to make up the quantity of circulating
fluid ; and if this faculty have only fluids to
work upon, it is evident that, as in the case of
bloodletting, the blood will become more serous
than before. The perspiration and the alvine
secretions act in this manner, and nature
makes use of these, especially of the former,
to temper the burning heat of paroxysms of
fever. Art but imitates nature in the treat-
ment of acute diseases ; she strives to procure
action of the skin, and especially action of
the bowels. The use of diaphoretics and pur-
gatives is therefore plainly borne out by the
principles which have been laid down. The
alvine secretions are those especially that carry
off the largest proportion of solid matters from
the blood, and which therefore, when excited,
prove the most permanently efficient in keep-
ing down the temperature of the body. There
is another important reason for preferring the
intestinal canal to the skin as the means, in
the generality of instances, of reducing tem-
perature in the treatment of disease, which
ought not to be lost sight of: this is, that
we can excite the intestinal evacuations to a
great extent without arousing the circulating
system in almost any degree ; very different
from what occurs when we attempt to unload
the vessels by the way of the cutaneous exha-
lants, in which it is generally impossible to
produce abundant diaphoresis without arous-
ing the heart and arteries to unwonted action
as a preliminary. Purgative medicines, there-
fore, next to the direct abstraction of blood,
are the most potent means of tempering the
heat of the body by modifying the consti-
tution of the blood. Nothing that influences
the economy can have an effect in one direc-
tion only. It were foreign to our purpose,
however, to enter upon any other than that
which bears immediately upon our subject.

There is another natural process analogous
in its effects, which the preceding consider-
ations place in a new point of view. This
is the influence of diet and regimen. Low
diet does not act merely in preventing the ex-
citement which always follows the ingestion of
solid food ; it further alters the constitution of
the blood. This fluid, receiving a more scanty
supply of solid matters, continues nevertheless
to supply the natural secretions as before, and
consequently very speedily undergoes by this
alone a diminution in the proportion of its
globules, in the direct ratio of the duration of
the system of spare diet. Low diet is there-
fore a means which acts in the same way as
bloodletting and purging, with this difference
however, that it is slower in its operation, and
in the first instance less marked in its effects.
This, therefore, is the slowest and least efficaci-
ous of the immediate means of reducing tem-
perature when employed alone, although its

conjunction is indispensable to the success of
any of trie others.

Of all these means, one only is the proper
effect of art, namely, the application of cold ;
the others are processes of the same natura
medicatrir, and processes which we merely
imitate. These act directly in modifying the
constitution of the blood, and thus definitively
influence the nervous system. The other
exerts its influence directly on the nervous
system, in calming the excitement or violent
action which it has engendered in the sangui-
ferous system, and those that depend on it.

The application of heat becomes necessary
in morbid states the reverse of those that
have just been discussed. The proper employ-
ment of this means depends especially on
two general principles bearing upon animal
heat, which we have considered above. 1st,
The one is, that the economy has the capacity
of bearing heat in the same proportion as
the function of respiration is extended. In
those cases in which this function is limited,
or, what comes to the same thing, where any part
that requires an accession of heat is indiffer-
ently supplied with arterial blood, it is neces-
sary to be extremely cautious in its applica-
tion. 2nd, The other, that the effects of ex-
ternal heat are not confined to the simple
interval during which it is applied, but remain
after it has been removed, and even increase
the faculty of producing heat. The applica-
tion of warmth is therefore not merely pallia-
tive or supplementary of lost heat; it has
further a directly remedial influence, which
may even be excited in excess. When the
lesion of the calorific faculty has been great,
without much or any organic lesion, other
means of greater force than those usually re-
sorted to by art, or employed by nature in
such circumstances, must be called in to assist.
Art has happily discovered what seems the
most effectual means of winding up the
nervous system, and enabling the calorific
faculty to be re-established in its normal con-
dition. This means is quinia, the first of
tonics. This powerful medicine is conse-
quently never administered in acute diseases
until all violence of action has ceased, and
the functions have resumed their habitual
rythm. We find that the action of this
medicine is exerted directly upon the nervous
system from this, that it seems to have no
effect on the secretions, or when it does in-
fluence these, we are convinced by the tri-
fling amount of the effect, that it is not through
them that the cure is accomplished. As it
acts during the intermission, by restoring the
normal production of heat, we have no reason
to expect the phenomena which characterize
the fit — the shivering, &c. ; and then the vio-
lent reaction which we have in the hot stage
becomes useless, and in fact is no longer ob-
served.

CONFIRMATION OF THE GENERAL RESULTS.
We have thus passed in review the principal
phenomena of animal heat, reducing or ap-
proximating these at all times to the most

ANIMAL HEAT.

683

simple conditions. These conditions them-
selves are, in the first place, assumed from
comparisons of the organization of the two
grand groups or series into which the animal
kingdom is divided with reference to heat —
the cold-blooded animals, and the warm-
blooded animals. In this review we have
avoided all hypothesis, confining ourselves to
the severe method of deduction, always starting
from well-authenticated facts, and even con-
firming each step in advance by new data
equally indisputable. The hurmony which
reigns in this comprehensive whole", which
embraces the different classes of animals and
man, not only in the various modifications of
health, but even of disease, in their relation
to external agents, and the therapeutic pro-
cesses of nature and of art, afford the surest
confirmation of the reality of these relations.
As the phenomena of animal heat are re-
ferable to two general conditions of the eco-
nomy,— the state of the blood and that of
the nervous system ; and as we have only in
the first instance deduced these from the com-
parison of natural facts, although we have
confirmed them by new observations and par-
ticular experiments, one may be desirous of
seeing them confirmed by experiments of a
more general bearing. To the reasonableness
of this wish we yield assent the more willingly,
as the results we have to quote are deductions
from some of the most admirable researches
that have been instituted by physiologists; —
I allude to the enquiries of Legallois, Sir
Benjamin Brodie, and Dr. Chossat.

The first of these experimenters, by the em-
ployment of various means for impeding re-
spiration, or limiting the consumption of air,
found that the refrigeration of animals is in
the compound ratio of the difficulty experienced
in breathing and of the quantity of oxygen con-
sumed ; so that when, in two experiments, the
d(fficulti/ of breathing is the same, the greatest
extent of cooling occurs in that in which the
smallest quantity of oxygen is vitiated, and the
contrary. Now, the end of the process of
respiration being to change the venous into
arterial blood, this conclusion of Legallois con-
firms directly the one of the two principal
conditions — THE STATE OF THE BLOOD, which we
have laid down as influencing the production
of heat among animals, and to the knowledge
of which we had attained by induction.

The results of the direct experiments which
we have still to quote also come powerfully
in aid of our inferences concerning the other
principal condition, which we have assumed
from induction, influencing the production of
animal heat: this is THE STATE OR ACTION OF

THE NERVOUS SYSTEM.

Sir B. Brodie demonstrated by a series of
the most ingeniously conceived and happily
executed experiments, that when animals were
decapitated and respiration was kept up by
artificial means, so that the blood circulated
as usual, and the process of change from the
venous to the arterial state went on uninter-
ruptedly, the ordinary quantity of carbonic
acid being eliminated, all the while, that, ne-

vertheless, the temperature fell rapidly, even
more rapidly than when no artificial respiration
was maintained.

Dr. Chossat completed these researches upon
the nervous system in its relations with the
production of heat, by demonstrating in a
series of experiments the following very im-
portant fact, viz. that the depression of animal
heat is constantly in relation with lesions of
the nervous system, whether these lesions im-
plicate the cerebro-spinal system, or the system
of the great sympathetic.

We necessarily confine ourselves, in alluding
to these admirable researches, to the most
general results, and the conclusions flowing
most immediately from the experiments insti-
tuted. We reserve a more particular mention
of them for the proper place, namely, the
article on RESPIRATION, to which we beg to
refer. With regard to the opinions of writers
generally, we shall be content to observe here,
that they have for the most part regarded the
single physiological condition which was the
subject of their particular study as the only
source of animal heat. The general result of
their united labours, however, is, that there
are two principal sources, the one depending
on the arterial blood, the other on the energy
of the nervous system, — a conclusion to which
we have come by another way, by combining
all the known facts that bear upon animal heat,
and embracing the manifestations presented by
the whole of the animal kingdom as well as
the isolated phenomena exhibited by man, and
this not in one but in every condition of ex-
istence, not only in the state of health but of
disease likewise, not as beings independent of
all things around them, but as living in intimate
relationship with external agents.

OF THE PHYSICAL CAUSE OF AN IMAL HEAT,

With regard to the physical cause of animal
heat, or to its mode of production, there was
a time, which we have not yet left very far
behind us, when natural philosophers and
chemists imagined they possessed the secret,
especially with reference to the mineral king-
dom. They have now discovered their mis-
take; and as the evolution of heat is a mystery
to them, it is not to be expected that it is less
so to physiologists, as manifested in the do-
main which they cultivate in peculiar. The
problem, in fact, becomes immensely com-
plicated by a variety of phenomena when from
the inorganic we ascend to the organic world.
All that could be done has been accomplished ;
from the particular conditions of organization
and of function upon which this effect
seemed to depend, physiologists have risen to
those that were the most general and com-
prehensive. This, in fact, was the end we
proposed in commencing this article. That
nothing may be omitted which can make the
sketch more complete, and none of the great
inquiries which have had animal heat for their
object may be passed over in silence, we shall
briefly cite the more important of those in
which the mode of production of animal heat
is discussed, always reserving to ourselves the

684

HEIIMAPHRODITISM.

opportunity of treating several of these more
fully in our article on RESPIRATION.

Lavoisier, from his labours on combustion,
which laid the foundation of the chemical
doctrines of the age that has just elapsed,
conceived the ingenious idea of explaining the
phenomena of animal heat by the combustion
of the carbon and hydrogen of the blood by
the oxygen of the air in the process of respi-
ration, and the experiments which he instituted
upon this point along with the illustrious La
Place appeared to confirm his idea. Still it
was found impossible to give an account of the
production of the whole heat engendered by
animals. All that Lavoisier and La Place in-
ferred was, that the heat evolved by an animal
was almost entirely produced by the combus-
tion which occurs in respiration. As the calo-
rific power was measured in one animal, and
the consumption of oxygen in another, it is
evident that the inference, vitiated in its ele-
ments, became much less precise than it would
otherwise have been.

This consideration as well as others induced
M. Dulong, who is as well versed in mecha-
nical philosophy as in chemistry, to take up
this subject again. After numerous experi-
ments, conducted with every precaution that
could secure accuracy of result, he found that
the heat disengaged by the fixation of the
oxygen in the act of respiration was not equal
to the whole of that which was produced by
an animal. This inquiry (which however stood
in no need of confirmation) has been con-
firmed by the analogous inquiries of M. De-
spretz, who arrived at the same numerical
results. The hypothesis in question, there-
fore, gives no solution of the problem.

The general works on Physiology, particularly
those of Rudolphi and Tiedemann. Czermack, On
the Temperature of Reptiles, in Zeitschr. fiir Phy-
sik, &c. Bd.3. Berthold, Neue v,'rsuche uber die
Temperature, &c. Getting. 1835. Transl. in Ann.
d'Anatomie, &c. Mai 1838. Newport, Temp, of
Insects, Phil. Trans. 1837. Becquerel $ Breschet,
Mem. surlaChaleur Animate, in Ann. des Sciences,
Nat. Seconde Serie, t. 3, 4, & 9.

( W. F. Edwards.)

BIBLIOGRAPHY.— Martine, Essay on the genera-
tion of Animal Heat, in Essays Med. and Philos.
Lond. 1740. Holler, De general, caloris, &c. Goett.
1741. Stevenson, Essay on the cause of Animal
Heat, &c. Med. Essays and Obs. vol. 5. Mortimer,
Letter concerning the Nat. Heat of Animals, Phil.
Trans. 1745. Braun, De calore animalium, Nov.
Comm. Petrop. t. 13. Duncan, Hypotheses of the
cause of Animal Heat, Med. and Phil. Com. vol.
6. Experts. £c. Min. of Society for Philos. Ex-
perts, p. 157. Martin (A.R.), Various Papers on
Animal Heat in the Svenska Vetensk. Akad. Hand-
lingar for the years 1764 and 1766. Hunter, Ex-
perts, on the power of producing Heat, and on the
Heat of Vegetables and Animals, Phil. Trans. 1775-
1778, and in Animal Economy. Crawford (D.J.M.),
De Calore A nimali, Edinb. Exprts. and Obs. on
Animal Heat, Phil. Trans. 1786, separately, 2d ed.
1788. Leslie, Philos. Inquiry into Animal Heat,
Lond. 1778. Rigby, Essay on the Theory of the
Prod, of Animal Heat, Lond. 1785. Deluroche et
Berger, Memoire, &c. in Journ. de Physique, t. 71.
Brodie, in Croonian Lecture, Phil. Trans. 1811.
Davy, An Ace. of some Experts, on Animal Heat,
Phil. Trans. 1814. •• Legallois, Mem. sur la chaleur
animale, Ann. de Chimie, t. iv. Earle, Influence of
the nervous system in regulating Heat, Med. Chir.
Trans, vol. vii. Chossat, Influence du Systeme
Nerveux surlaChaleur Animale, These, Paris, 1820.
Dulong, De la Chaleur Animale, Journ. de Physiol.
t. 3. Despretz (Rich.}, Exper.sur la Chaleur Anim.
Ann. de Chimie, t. 26. Home, Influence of the
Nerves in producing Animal Heat, Phil. Trans, v.
115. Collard de Martigny,De ^Influence de la Cir-
culation, &c. sur la Chaleur du Sang, Journ. Com-
plena, t. xliii. Vide also Journ. Complem. t. xxvi.

HERMAPHRODITISM,

DISM;* Hermaphrodisia; androgynisme, gynan-
drisme ; hermaphroditisme, &c., of the French ;
ermaphrodismo of the Italians ; Zwitterbildung
of the Germans, &c.

Many different definitions of hermaphro-
ditism, and almost an equal number of diffe-
rent classifications of the malformations usu-
ally comprehended under it, have been proposed
by the various authors, ancient and modern,
who have directed their attention to this sub-
ject. Without stopping to discuss the merits
or errors of these definitions and classifications,
and without inquiring, as some have done,
into the propriety of the word itself, we shall
content ourselves with stating that under it, as
a convenient generic term, we purpose in the
present article to include an account — 1st, of
some varieties of malformation in which the
genital organs and general sexual configura-
tion of one sex approach, from imperfect or ab-
normal developement, to those of the opposite;
and 2d, of other varieties of malformation, in
which there actually coexist upon the body of
the same individual more or fewer of the geni-
tal organs and distinctive sexual characters
both of the male and female.

To separate from one another, by as strong a
line as possible, the two distinct varieties of
hermaphroditic malformation marked out in
this definition, we shall divide hermaphroditic
malformations, considered as a class, into the
two orders of Spurious and True ; the spurious
comprehending such malformations of the
genital organs of one sex as make these organs
approximate in appearance and form to those
of the opposite sexual type; and the order,
again, of true hermaphroditism including
under it all cases in which there is an actual
mixture or blending together, upon the same
individual, of more or fewer of both the male
and female organs.

Spurious hermaphroditism may occur either
in the male or female ; that is, there may, from
malformation of the external sexual organ, be
an appearance of hermaphroditism in persons
actually of the female sex, or from a similar
cause there may be an appearance of herma-
phroditism in persons actually of the male sex.
The differences derived from the diversity of
sex in which spurious hermaphroditism occurs,
and the particular varieties of malformation in
each sex which may give rise to it, will serve as

* From the well-known mythological fable o^
the union into one, of the bodies of Hermaphro-
dites (the son of Ep^ujjf, Mercury, and A<f>f«8Vr»i»
Venus,) and the nymph Salmacis. See Ovid's Me~
tamorphoses, lib. iv. lab. 8.

HERMAPHRODITISM.

685

bases on which we shall found some further
subdivisions of this order.

True hermaphroditism, as above defined,
comprehends also, as shall be afterwards more
particularly shewn, several very distinct varieties
of malformation. If we conceive for a mo-
ment all the reproductive organs to be placed
on a vertical plane, (as we may suppose them
to be, though not with strict correctness, in the
human body when in the erect posture,) we
shall find that the principal of these varieties
may be all referred to three sets of cases : —
1st, those in which, if we drew a vertical
median line through this supposed plane, the
two lateral halves will be seen to present organs
differing in this respect, that they belong to
opposite sexual types ; 2d, others in which,
if we bisect the same plane by a transverse
horizontal line, there exist organs of a different
sex in the upper from what are present in the
lower segment ; or, in other words, the internal
genital organs belong to one sex, and the ex-
ternal to another. Tn the two preceding classes
of cases there is not necessarily, as we shall
afterwards more fully point out, any malforma-
tion by duplicity in the sexual apparatus of the

malformed individual ; there is only one set of
sexual organs present, but in some parts these
organs are formed upon the male, and in others
upon the female type. In the 3d and re-
maining set of cases, however, there is really
present to a greater or less, though most gene-
rally only to a very partial extent, a double set
of sexual organs, having opposite sexual cha-
racters, so that upon the same body, and usu-
ally upon the same side, or upon the same
vertical line in our supposed plane, we find
coexisting two or more of the analogous organs
of the two sexes. In accordance with this
view, we shall consider the cases of true her-
maphroditic malformation under the three
corresponding divisions of, 1st, lateral; 2d,
transverse ; and 3d, vertical, or, more properly,
double or complex hermaphroditism ; and each
of these genera will admit of some further
convenient subdivisions. But the mode in
which we propose to classify and consider the
subject will probably be at once more accurately
gathered from the following table, than from
any more lengthened remarks upon it in the
present place.

Classification of hermaphroditic malformations.

From excessive development of the clitoris,

'In the Female

Hermaphroditism

Spurious

&c.
From prolapsus of the uterus.

f From extroversion of the urinary bladder.
In the Male. . < From adhesion of the penis to the scrotum.
C From hypospadic fissure of the urethra, &c.

/- Testis on the right, and ovary on the left
> side.

r Lateral

True ..

\ Testis on the left, and ovary on the right

Transverse

Vertical or
Double .

In commenting upon and illustrating the
different varieties of hermaphroditism in the
particular order in which they are placed in the
above table, we shall, we believe, by following
that order, be able to take a graduated, and, at
the same time, a correct and comprehensive
view of the subject, beginning with the more
simple, and ending with the more complex and
complete species of hermaphroditic malforma-
tion, as seen in the primary sexual characters,
or the structure of the genital parts themselves.
We shall then consider at some length the
curious and important physiological subject of
hermaphroditism as manifested in the secondary
sexual characters of the system. After having
done so, we shall endeavour to show how far

side.

c External sexual organs female, internal male.
( External sexual organs male, internal female.

/-Ovaries and an imperfect uterus with male
vesiculae seminales, and rudiments of vasa
deferentia.

1 Testicles, vasa deferentia, and vesiculse se-
minales, with an imperfect female uterus
and its appendages.
Ovaries and testicles coexisting on one or
both sides, &c.

the diversified forms of hermaphroditic malfor-
mation can be explained upon our present
knowledge of the laws of developement ; point
out the actual anatomical and physiological
degree of sexual duplicity which is liable to
occur, and the numerous fallacies with which
the determination of this question in individual
cases is surrounded ; and lastly, in conclu-
sion, we shall offer some general observations
upon the causes, &c., of this class of abnor-
mal formations.

I. SPURIOUS HERMAPHRODITISM.

A. In the female. — There are two circumstances
in the conformation of the genital organs of the
female, the existence of each of which has oc-

686

HERMAPHRODITISM.

casionally given rise to doubts and errors with
regard to the true sex of the individual on
whom they were found — namely, 1st, a pre-
ternaturally large size of the clitoris ; and 2d,
a prolapsus of the uterus; the enlarged cli-
toris in the one case, and the protruded ute-
rus in the other, having been repeatedly mis-
taken for the male penis.

1. Abnormal developement or magnitude of
the clitoris. — In the earlier months of intra-
uterine life, the clitoris of the human female is
nearly, if not altogether, equal in size to the
penis of the male fetus; and at birth it is
still relatively of very considerable dimensions.
From that period, however, it ceases to grow in an
equal ratio with the other external genital parts,
so that at puberty it is, as a general law, found
not to exceed six or eight lines in length.
But in some exceptional instances the cli-
toris is observed to retain up to adult
age more or less of that greater pro-
portionate degree of developement which
it presented in the embryo of the third
and fourth month, thus exhibiting in a per-
sistent form the transitory type of structure
belonging to the earlier stages of fatal life.
In some instances where this occurs, the re-
semblance of the external female to the exter-
nal male parts is occasionally considerably in-
creased by the apparent absence of the nymphae.
Osiander* endeavoured to show that at the
third or fourth month of foetal life the nymphae
are very imperfect, and so very small as not to
be easily observed. Meckel,f however, has
pointed out that these organs are not in reality
of a small size at that time, but they are liable
to escape observation from the folds of skin of
which they consist, making, at the period
alluded to, a perfectly continuous membrane
with the prepuce of the clitoris, and forming
indeed, in their origin, only one common mass
with this latter body. When the ulterior
changes, therefore, which these parts ought to
undergo in the natural course of developement
in the latter stages of fetal existence, are sus-
pended or arrested from about the end of the
third month, there may not only coexist with
the enlarged clitoris an apparent want of nym-
phae, but the resemblance of the female to the
male parts may be still further increased by the
persistence of the original intimate connexion
of the nymphae with the prepuce and body of
the clitoris, and by the consequently continuous
coating of integuments, as well as the greater
size and firmness of this organ.

Excessive size of the clitoris would seem to
be much less common among the natives of
cold and temperate than among those of warm
countries. The frequency of it in the climate
of Arabia may be surmised from the fact of
directions having been left by Albucasis and
other surgeons of that country for the amputa-
tion of the organ ; an operation which .ZEtius
and Paulus Eginetus describe as practised
among the Egyptians. According to the more

* Abhandlungen liber die Scheidenklappe, in
Denkwurdigkeiten fur die Heilkunde, Bd. ii. p.4-b'.
t Manuel d'Anat. Gen. torn. iii. p. 666.

modern observations of Niebuhr* and Son-
nini,f circumcision would seem to be still
practised upon the females of that country.

This variety of conformation of the female
parts appears to have been well known to the
ancient Greeks, and several of their authors
have mentioned the women so constituted
under the names of rp^»^e<; and tToufunpiou,
a class in which the celebrated poetess Sappho
(mascula Sappho) is well known to have been
included. Martial, Tertullian, and other Ro-
man authors have noticed the same malforma-
tion, (fricatricest confricatrices,) and alluded
to the depravity to which it led/J;

* Beschreibung von Arabien, s. 77.

t Voyage dans la Haute et Basse Egypte, torn. ii.
p. 37.

$ Mart. Epigr. lib. i. ep. 91. ; see also lib. viii.
ep. 66. The frequency of this crime in the ancient
gentile world may be inferred from the pointed
manner in which the Apostle Paul alludes to it,
Romans, chap. i. 26. In Greece it was in some
places forbidden by law, and in others, as in Crete,
tolerated by the state. Seneca, in his 95th ep.,
•when speaking of the depravity of the women
of his own age, remarks, " non mutata fremina-
rum natura, sed vita est. . . . Libidine vero, nee
maribus quidem cedunt pad natze. Dii illas deaeque
male perdant, adeo perversum commentae genus
impudicitiae viros ineunt." Op. Om. Genev. 1665,
p. 787. Clemens Alexandrinus, in his Psedagogus,
exposes the same vice : " et contra naturam fnemi-
nae, viros agunt (avfy>{£ovTai) et nubunt et etenim
uxores ducunt." Also Athenaeus, Deipnosoph.
lib. xiii. p. 605. Justin Martyr, in his Second
Apology, makes a still broader accusation. This
author lived in the second century, and in declaim-
ing against the vices of that licentious age, he
alleges that multitudes of boys, females, and her-
maphrodites (androyyni ambigui sexus) " nefandi
piaculi graiia per nationem ornnem prostant." Op.
Om. Col. 1686, p. 70. See also Marcus Antoni-
nus, De Seipso, ed. Gatakeri, Cambr. 1652, lib. iii.,
note at the end by Gataker. On the extent, among
the ancients, of the vices above alluded to, s<*e
Meiner's Geschichte des Verfalls der Sitten und
der Stuatsvevfassung der Roemer, Leipzig, 1791 ;
Neander's Denkwurdigkeiten, Bd. i. s. 143; Pro-
fessor Tholuck's, of Halle, Exposition of St. Paul's
Epistle to the Romans, in the Edinburgh Biblical
Cabinet, vol. v. p. 102, and in an Essay on the
licentious vices, &c., of the ancients, translated
into Robinson's American Biblical Repository, vol.
ii. p. 441. In the essay last referred to, Tholuck
incidentally mentions (p. 422,) that the deity Mi-
tra (Mithras of the ancient Persians) was herma-
phrodite. For our own part we are inclined to
believe that many of the idols of the heathenish
mythology of Asia could be traced to the .deifica-
tion of various monstrosities in man andj quadru-
peds. (See the figures of these idols passim in C.
Coleman's Mythology of the Hindus, Lond. 1832;
and E. Upham's History and Doctrine of Budhism,
Lond. 1829.) It perhaps is not unworthy of no-
tice that the Jewish Talmudists, taking the Hebrew
noun in the Pentateuch answering to man in its
individual and not in its collective sense, consi-
dered, from Genesis, chap. i. v. 21, that our origi-
nal progenitor was hermaphrodite. (See Jus Tal-
mud. Cod. Erwin. c. 2; Heidegg. Hist. Patriarch,
t. i. 128 ; C. Bauhin De Monstrorum Natura, &c.,
lib. i. c. 24; and Arnaud's Memoire, p. 249.) It is
further interesting to remark that Plato, in his
Symposion, introduces Aristophanes as holding the
same opinion. " The ancient nature," he observes,
" of men was not as it now is, but very different;
for then he was androgynous both in form and

IIERMAPHRODITISM.

687

The dimensions which the clitoris occasion-
ally presents are such as to render it, in respect
of size alone, not unlike the male penis. It is
not unfrequently found of two or three inches
in length, but sometimes it is seen five and six
inches long. Dr. Clark frequently found the
organ an inch long, and thick in proportion,
among the Ibbo and Mandingo women.*

Hallerf and ArnaudJ have collected nume-
rous instances of preternatural size of the cli-
toris. The former author alludes, among others,
to two cases in which the crgan was stated to
have been seven inches in length ; and to an-
other, mentioned by Chabart, in which it was
alleged to have been twelve inches, — a size
which we can only conceive to have been the
result of disease.

When the female clitoris is increased greatly
in size, it is not wonderful that it should be
sometimes mistaken for the male penis, — the
female organ in the Mammalia naturally differ-
ing from the male only in regard to its smaller
dimensions, its not being perforated by the
urethra, and its wanting the corpus spongio-
sum, — a peculiarity or defect of structure that
exists as the natural type of fonnation in the
penis of male reptiles. In the human subject
the organs are composed internally of the same
kind of erectile tissue, and when we descend in
the animal scale, and examine their relations in
the males and females of the same species, we
find some still more striking analogical peculi-
arities of structure. Thus, in several of the
Carnivora and Rodentia, as in the lioness, cat,
racoon, bear, marmot, &c. the clitoris contains
a small bone like that belonging to the penis
of the males of the same species ; and amongst
the Monotremata and Marsupiata the clitoris
of the female, like the penis of the male, is
surmounted by a bifid glans. In a species of
lemur (Loris gracilis or Stenops tardigra-
dus), the clitoris is of a very large size ; and
the urethra, as first pointed out by Daubenton,§

cti E.^OJ xat ovcfjiet.} Probably from
the licentious purposes alluded to by Justin Martyr,
or from the weak and imbecile character of her-
maphrodite individuals, the word avfyx/ytyof came in
latter times to signify effeminate and luxurious.
The ancient lexicographer Hesychius gives it this
meaning ; and Theodoret, in his Therap., speaks of
Bacchus as being licentious, effpiniiiate, and an-
drogynous — (yuwi? a>y, KO.I SnXuJfJitt?, KO.I avS'poyuvof . )

* Home's Comp. Anat. vol. iii. p. 317. On the
peculiarities of the external genital organs in va-
rious African tribes, see a learned paper by Prof.
Miiller in his Archiv fuer Anatomie for 1834. Ht.
iv. s. 319., with ample references to the observa-
tions and opinions of Levaillant, Barrow, Peron,
Lesner, Lichtenstein, Burchell, Somerville, &c.
See also Otto, in his Neue Seltene Beobachtungen
zur Anatomie, p. 135, shewing the very prominent
external female parts of different African tribes to
consist differently, 1, of enlarged nymphae, 2, of
enlarged labia, and 3, of the enlarged clitoris.

t El. Phys. torn. vii. part ii. p. 81, 82.

$ Dissertation sur les. Hermaphrodites, p. 372.
See also Homberg, DeExcrescentiaClitoridis nimia,
Jena, 1671 ; Tronchin, De Clitoride, Lugd. 1736 ;
and Ploucquet's Literatura Medica, art. Clitoris
Magna, torn. i. p. 299.

§ Audibert, Histoire Nat. des Singes, tab. ii.

fig: s.

runs forward and opens at its anterior extre-
mity between the branches of its glans, imita-
ting, in this point of structure, the penis of the
male among the Mammalia.

In the human subject the mere enlargement
of the clitoris alone has seldom of itself given
rise to errors with regard to the sex of the indi-
vidual, except in young children ; but it has
frequently happened that along with it other
minor malformations have coexisted, so as to
render the sexual distinction much more ambi-
guous. In women possessing this peculiarity
of structure we sometimes observe, for in-
stance, the clitoris not only resembling the
penis in size, but it has an indentation at the
point of the glans, imitating the orifice of the
urethra ; and occasionally the glans is actually
perforated to a certain extent backwards, or
the body of the clitoris is drilled more or less
imperfectly with a canal like that of the male
urethra. In other instances the canal and
orifice of the female vagina are, by an excess
of development in the median line of the
body, much contracted or nearly shut up, the
vulva being closed by a strong membrane or
hymen, and the labia cohering so as to give the
parts a near resemblance to the united or closed
perinaeum and scrotum of the male. Further,
in one or two very rare cases which have been
put upon record, the ovaries and Fallopian
tubes seem to have descended through the in-
guinal rings into the labia, thus giving an ap-
pearance of the presence of testicles ; and a
fallacy seems to have occurred in some cases
from the presence of roundish masses of fat
in this situation simulating more or less the
same male organs.

Besides, it often happens in those women
who present more or fewer of these peculiarities
of conformation in the external genital parts,
that the general or secondary sexual characters
of the female are wanting, or developed in a
slighter degree than natural, owing probably
to the malformations of the external organs
being often combined with some coexisting
anomalies in those more important internal re-
productive organs, the healthy structure and
action of which at the time of puberty appear
to exercise so great an influence on the deve-
lopment of the peculiar general conformation
and moral character of the female. Thus the
features are sometimes hard, the figure and
gait rather masculine, the mammse slightly
developed, the voice is deep-toned, and the
chin and upper lip are occasionally covered
with a quantity of hair. In fact, in some
marked cases the whole external character ap-
proaches to that of the male, or, more pro-
perly speaking, occupies a kind of neutral
ground between that of the two sexes. Some
of the more striking examples of this first va-
riety of spurious hermaphroditism in the fe-
male will sufficiently illustrate the above re-
marks.

Dr. Ramsbotham* has briefly described the
genital parts of an infant, that was christened
and looked upon as a boy, until dissection after

* Medical Gazette, xiii. p. 184.

688

IIERMAPHRODITISM.

death shewed that the sex was actually female.
The uterus and other female organs (fg- 287,
c c c) were present and apparently naturally

fig. 287

formed ; but the clitoris (b} was fully as large,
and in appearance closely resembled the penis
of a male of the same age. At its anterior
extremity there was a sulcus («), which was
not the entrance of the urethra, but terminated
in a cul-de-sac.

Columbus* and De Graaff give two similar
examples of the same form of spurious her-
maphroditism in young children, in which the
true sex was only fully ascertained by dis-
section after death. In relation to the clitoris
in the case described by Columbus, that author
states that this organ was furnished with two
muscles only, and not with four, as in the per-
fect male.

In a reputed hermaphrodite woman, Gallay J
found after death the clitoris to be three and a
half inches long, and three inches and four
lines in circumference. The glans and prepuce
were well developed. The urethra ran as in
man through the body of the penis and its
glans. The labia, nymphae, vagina, &c. were
natural, and the internal female organs, the
ovaries, Fallopian tubes, and uterus, are de-
scribed as scirrhous. This woman had been
married, but never had any children ; her ca-
tamenia, however, had been very regular. She
had a considerable quantity of hair upon her
face, and her voice was harsh and masculine.

In a child of two years of age, Schneider,§
on dissection after death, could find neither
the labia externa nor interna, nor any trace of
the ordinary cleft between them. The clitoris
was an inch and a half long, and externally
resembled most perfectly a male penis fur-
nished with a glans and prepuce ; but it was
imperforate, having only at its anterior extre-
mity a small spot marking the situation of the
opening of the urethra in the male. Some

* De Re Anatomica, lib. xv. p. 493.

t Op. Om. cap. iii. xv. or, De mulierum organis
gen. inserv. with a plate.

* Arnaud, 1. c. p. 309.

§ Jahrbiicher der Staatsarzneikunde, (1809),
». 193.

lines below there was an opening by which
the urine was evacuated. This opening formed
the entrance to the vagina, which was found of
the usual length, and with the characteristic
rugae. The canal of the urethra was found
entering its roof, but in such a manner that
the urine was always evacuated very slowly
and by drops only from the external opening.
All the internal female sexual organs were
natural.

M. Beclard* has left us a very detailed and
interesting description of an example of spu-
rious hermaphroditism referable to the present
variety, and exhibited at Paris in 1814. The
subject of the case, Marie Madeline Lefort,
was at that time sixteen years of age. The
proportions of the trunk and members, and of
the shoulders and pelvis, and the conformation
and dimensions of this last part of the body,
were all masculine; the volume of the larynx
also, and the tone of the voice were those of
an adolescent male; a beard was appearing on
the upper lip, chin, and region of the parotids;
some hairs were growing in the areola around
the nipple ; and the mammae were of a mode-
rate size. The inferior extremities were fur-
nished with an abundance of long hard hairs.
The symphysis pubis was elongated as in man ;
the mons veneris rounded, and the labia ex-
terna were covered with hair. The clitoris was
10^ (?) inches (27 centimetres) in length when
at rest, but somewhat more when erect; its
glans was imperforate, and covered in three-
fourths of its circumference with a mobile pre-
puce. The body of this enlarged clitoris was
furnished inferiorly with an imperfect canal,
which produced a depression in it, instead of
that prominence of this part which exists in the
male penis. This canal was pierced along its
under surface and median line by five small
holes capable of admitting a small stylet ; and
one or more similar apertures seemed to exist
in it after it reached backwards within the va-
gina. The labia were narrow and short, and
the vulva or sulcus between them was superfi-
cial, being blocked up by a dense membrane,
which, under the pressure of the finger, felt as
if stretched towards the anus over a cavity. At
its anterior part, or below the clitoris, there was
an opening capable of admitting a sound of
moderate size, and this sound could be made
to pass backwards behind the membrane closing
the vulva, which, when felt between the point
of the instrument and the finger, seemed about
twice as thick as the skin. The urine was
passed by this opening, and also, according to
the report of the individual herself, through
the cribriform holes in the canal extending
along the inferior surface of the urethra. By
the same opening the menstrual fluid escaped,
as Beclard ascertained on one occasion by per-
sonal examination. She had menstruated re-
gularly from the age of eight years, considered
herself a female, and preferred the society of
men.

In this interesting case we have present all
the secondary sexual characters of the male,

* Bulletins de la Faculte for 1815, p. 273.

HERMAPHRODITISM.

689

with some of the female genital organs deve-
loped in so excessive a degree as to approach
in several points the more perfect structure of
them in man. The impossibility, however, as
mentioned by Beclard, of finding any bodies
like testicles in the labia or in the course of
the inguinal canals, and more particularly the
well-ascertained fact of the individual menstru-
ating, can leave no doubt as to the nature of
her sex. The perforation of the enlarged cli-
toris with the imperfect urethra is interesting,
when compared with the peculiarities that we
have formerly alluded to, of this part in the
female Loris, as pointing out, what we have so
often occasion to observe in human monstrosi-
ties, a type of structure assumed by a mal-
formed organ similar to the normal type of struc-
ture of the same organ, in some of the inferior
animals.

Arnaud* has represented and described at
great length an interesting example of herma-
phroditic malformation that seems referable to
the head of spurious hermaphroditism in the
female, although there are two circumstances
in the history of the case which have led some
authors to doubt the accuracy of this opinion ;
and the opportunity that was afforded of ascer-
taining the true structure of the parts after
death was unfortunately lost through careless-
ness and neglect. The subject of the malfor-
mation, aged 35, passed in society for a female,
and came to Arnaud complaining of a small
tumour (fg. 288, e) in the right groin, which

Fig. 288.

had incommoded her much during her whole life.
On examining this body, Arnaud was led to
believe that it was a testicle, and he found a
similar tumour (f} situated nearer the inguinal
ring on the left side. The bags that contained
them represented very exactly the labia externa.
The clitoris (a) was two inches and nine lines
in length, and placed between the labia at their
upper angle. The glans (b) was well formed,
and though imperforate at its extremity, it pre-
sented a small depression which ran backwards
along the whole inferior border of the clitoris,
indicating the situation of a collapsed urethra!
canal, that seemed pervious for some length at

* Dissertation sur les Hermaphrodites, p. 265,
pLx.

VOL. II.

its posterior part, as it became distended when
the patient evacuated the bladder. The ori-
fice (c), however, from which the urine actually
flowed, occupied the situation in which it exists
in the perfectly formed female. There was not
any vaginal opening, and the individual men-
struated per anum. At each menstrual period
a tumour (rf) always appeared in the perinaeum,
which gradually increased in size, becoming, in
the course of three or four days, as large as a
small hen's egg. When the perinaeal tumour
had reached this size, blood began to flow
from the anus, although no haemorrhoids or
other disease of the bowel was present. At
these periods the individual had often expe-
rienced very alarming symptoms, and in order
to avert these, Arnaud was induced to make an
opening into the soft yielding space at which
the perinaeal tumour above alluded to appeared;
and at a considerable depth he found a cavity
two inches in circumference, and about two
and a half in breadth, having projecting into it
at one point an eminence which was supposed
from its situation to be possibly the os uteri.
At the next period the menstrual fluid came
entirely by the artificial perinaeal opening, and
the usual severe attendant symptoms did not
supervene. From inattention, however, to the
use of the tent, the opening was allowed to
become completely shut, so that at the sixth
return of the menses they flowed again by the
anus, and were accompanied by the old train
of severe symptoms. The individual lived for
several years afterwards. Her conformation of
body was remarkable. Her skin was rough,
thick, and swarthy; she had a soft black beard
on her face ; her voice was coarse and mascu-
line ; her chest narrow ; her mammae were flat
and small ; her arms lean and muscular ; her
hands large, and her fingers of very considerable
length and strength. The form, in fact, of the
upper part of her body was masculine, but in
the lower part the female conformation predo-
minated. The pelvis was wide and large, the
os pubis very elevated, the buttocks large, the
thighs and legs round, and the feet small.

In this remarkable instance, if we do not go
so far as to conceive the coexistence of some
of the internal organs of both sexes, we must,
from the well-ascertained fact of the menstrual
evacuations, allow the person at least to have
been a female. In that case we can only sup-
pose the tumours in the labia to be the ovaries
descended into that situation ; and to the same
excess of development which has produced this
effect, we may attribute the closure of the
vaginal orifice, and the formation of the imper-
fect urethral canal in the body of the clitoris.

Spurious hermaphroditism from preternatural
enlargement of the clitoris has been recognised
among some of the lower animals. Rudolphi*
has noticed a mare of this kind that had a
clitoris so large as almost to shut up the en-
trance into the vagina. Lecoqf has detailed

* Rudolphi's Bemerkungen auf einer Reise, &c.
Bd. i. s. 79. See a case also figured by Ruysch in
his Thesaurus Anat. lib. viii. no. 53.

t Journ. Prat, de Med. Vet. 1827, p. 103.

2 7.

690

HERMAPHRODITISM.

the case of a calf which Gurlt* believes to
belong to the present head. Neither testicles
nor scrotum were observed externally, and the
penis or enlarged Clitoris, which occupied its
normal situation, was apparently perforated by
the urethra, and crooked upwards so as to
throw the urine in that direction. Meryf
shewed by dissection the true sex of a monkey,
the length of whose clitoris had deceived some
observers with regard to the true sex of the
animal. The enlarged clitoris was furrowed
on its inferior surface. The clitoris of the
female Quadrumana is, as shall be afterwards
more particularly mentioned, relatively larger
than in the human subject, and retains in a
greater degree the size and type of structure of
this organ in the embryo.

We may here further mention that, as pointed
out by Blumenbach,t the clitoris and orifice of
the urethra are placed at some distance from
the vagina and in front of it, in the rat, mouse,
hamster, &c. This normal structure has some-
times been mistaken for an hermaphroditic mal-
formation^

2. From prolapsus of the uterus. — It may
at first appear strange that this occurrence
should ever lead to any difficulty in ascertain-
ing the sex of the individual, though not only
non-professional observers but even the most
intelligent medical men have occasionally been
so far misled by the similarity of the protruded
organ to the male penis, as to mistake a female
for a male. Of this circumstance some curious
illustrations are on record.

M. Veay, physician at Toulouse, has inserted
in the Philosophical Transactions of London,
vol. xvi. p. 282, a brief account of the case of
Marguerite Malause or Malaure, who was
entered as a female patient in the Toulouse
Hospital in 1686. Her trunk, face, &c. pre-
sented the general configuration of a female,
but in the situation of the vulva there was a
body eight inches in length when on its fullest
stretch, and resembling a perfectly formed male
penis in all respects, except in not being pro-
vided with a prepuce. Through the canal
perforating this body she was alleged to eva-
cuate her urine, and from its orifice M. Veay
had himself an opportunity of seeing the men-
strual fluid flow. After being examined by
several physicians she was pronounced to be
more male than female, and ordered by the
civil authorities to exchange the name of Mar-
guerite for that of Arnaud, and to wear male
attire. In 1693 she visited Paris in her male
habiliments, and reputed herself endowed with
the powers of both sexes. The Parisian phy-
sicians and surgeons who examined her seem all
to have accorded in opinion with the faculty of
Toulouse, until M. Saviard|| saw her and de-
tected the supposed penis to be merely the
prolapsed uterus. He reduced the protruded
organ, and cured the patient. Upon the enigma

* Lehrbuch der Pathol. Anat. Bd. ii. s. 193.
t Hist, de 1'Acad. (1686) torn. i. p. 345.
$ Comp. Anat. p. 335.

§ Doebel, in Nov. Liter. Maris Balthici (1698),
p. 238.

|| Rccueil d'Observations Chirur^icales, p. 150.

of her hermaphroditism being thus solved, she
was permitted by the king, at her own request,
to assume again her female name and dress.

Sir E. Home* detected a case of reputed
hermaphroditism of the same description as the
last, in a French woman of twenty-five years of
age, who exhibited herself in London, and
pretended to have the powers of a male. The
cervix uteri was uncommonly narrow, and pro-
jected several inches beyond the external open-
ing of the vagina. The everted mucous surface
of the vagina had, from constant exposure, lost
its natural appearance and resembled the ex-
ternal skin of the penis. The orifice of the os
tincse had been mistaken for the orifice of the
urethra. The prolapsus had been observed at
an early age, and had increased as the woman
grew up.

Valentin f mentions another analogous in-
stance of sexual ambiguity produced by a
prolapsus of the uterus. In this case the
husband mistook the displaced organ for the
penis, and accused his wife of having " cum
sexu virili necquicquam commune."

A case quoted at great length by Arnaud J
from Duval, of reputed hermaphroditism in a
person that was brought up as a woman, and
married at twenty-one years of age as a male,
but who was shortly afterwards divorced and
imprisoned, and ordered again by the Court
of Rouen to assume the dress of a woman,
appears to us to belong very probably to the
present division of our subject, the reputed
penis being described as placed within the
vagina. The recorded details of the case,
however, are not so precise as to leave us with-
out doubt in regard to its real nature.

In cases such as those now mentioned, in
which the prolapsed uterus, or, more properly
speaking, the prolapsed uterus and vagina have
been mistaken for the penis, it appears proba-
ble that the neck of the uterus must have been
preternaturally long and narrow, otherwise it
would be difficult to account for the apparent
small diameter and great length of the prolapsed
organ. Among Professor Thomson's collection
of anatomical drawings of diseased structures
there is one of an uterus containing in its body
a fibro-calcareous tumour, and having a neck
of three inches in length. M. Cruveilhier§
has represented a similarly diseased uterus with
a neck of between five and six inches. An
organ shaped in this manner, whether from
congenital malformation or acquired disease,
would, when prolapsed for some time, repre-
sent, we conceive, a body resembling in form
and size those observed in "Saviard's and Home's
cases. The prolapsus arising from a protrusion
of an ordinary shaped uterus is generally of a
greater diameter and roundness.

This second species of spurious female her-
maphroditism is not observed among the lower
animals.

B. Spurious hermaphroditism in the male. —

* Comp. Anat. vol. iii. p. 318.

t" Pandectoe Medico- Legales, t. i. p. 38, Casus xii.

i;Mem. sur les Hermaphr. p. 314-18.

$ Anat. Pathol. liv. xiii. PI. iv.

IIERMAPIIRODITISM.

691

Malformed males have been more often mis-
taken for females than the reverse. The varieties
of malformation in persons actually male, that
are liable to lead to mistakes with regard to
their true sex, appear to be, 1st, extrophy or
extroversion of the urinary bladder; 2d, ad-
hesion of the inferior surface of the penis to
the scrotum ; and 3d, and principally, fissure
of the inferior part of the urethra and of the
scrotum and perinaeum.

1. Extroversion of the urinary bladder. —
For a full description of this malformation we
must refer to the articles BLADDER and MON-
STROSITY. This malformation is known to
occur more frequently in the male than in the
female, and when present in the former it has
occasionally given rise to a supposition of her-
maphroditism, the red fungous mass formed
by the mucous membrane of the protruded
posterior wall of the bladder, and situated
above the pubis, having been mistaken for the
female vulva, — an error which has probably
been the more readily committed from the
uterus and seminal ducts, and sometimes also,
as in an instance described by A. Fraenkel,* a
part of the intestinal canal opening upon the
surface of the exposed portion of bladder. In
some instances of this malformation occurring
in man, the external male sexual organs are
very imperfectly formed, or can scarcely be
said to be at all present. In other cases the
scrotum is of the natural form, with the two
testicles in it; and the penis is of considerable
size, though almost always fissured on its upper
surface from the epispadic or open state of the
urethra.

An example of supposed hermaphroditic
malformation briefly described by Rueffe,f
which seems referable to this variety will be
sufficient to illustrate it. " In the year 1519
an hermaphrodite or androgynus," he remarks,
" was born at Zurich, perfectly formed from
the umbilicus upwards, but having at this part
a red mass of flesh, beneath which were the
female genitals, and also under and in their
normal situation those of the male."

2. Adhesion of tlie inferior surface of the
penis to the scrotum by a band of integuments.

—This state of parts has occasionally given
rise to the idea of hermaphroditism, the penis
being so bound down as not to admit of erec-
tion, and the urine passing in a direction
downwards, so as to imitate the flow of it from
the female parts.

In a boy of seven years of age regarding
whom Brand I was consulted, the penis was
confined in this manner to the scrotum by
abnormal adhesions. He had been baptized
and reared as a girl, but by a slight incision
the adherent organ was liberated, and the
parents were convinced of the mistake that they
had committed in regard to the sex of their
child. The difficulty of determining the true

* De Organorum Generationis Deform. Rarissi-
ma, Berlin, 1825, with a plate.

t De Conceptu et Generatione Hominis, p. 44.

$ Case of a boy who had been mistaken for a
girl. London, 1788.

sex of the boy was increased by the testicles
not having descended into the scrotum.

Wrisberg* mentions two similar instances
in persons of the respective ages of nineteen
and forty-six. He relieved the adherent penis
in the first case by operation.

3. Fissure of the inferior part of the ure-
thra, perineum, fyc. — This species of mal-
formation, which has perhaps more frequently
than any other given rise to the idea of the
person affected with it being the subject of
hermaphroditism, evidently consists in an arrest
of the development of the external male sexual
parts.

At an early stage of the development of the
embryo, the various central sexual organs are,
like all the other single organs situated on the
median line of the body, found to be composed
of two separate and similar halves, divided
from each other by a vertical fissure, which,
after the originally blind extremity of the intes-
tinal canal has opened upon the perinaeum,
forms a common aperture or cloaca for the
intestinal canal, and also for the urinary and
genital apparatus, both of which are, in their
primary origin, prolongations from the lower
part of that canal. After a time, (about the
second month in the human embryo,) the
opposite sides of this cloaca gradually approxi-
mate, and throw out two corresponding folds,
which by their union constitute a septum that
separates the rectum from the canal or portion
of the fissure, that still remains common to
the urinary and generative organs ; and, in the
same way, by two similar and more anterior
folds, the urethra of the female, and the pelvic
portion of that of the male is subsequently
produced. After this in the female the process
of median reunion does not proceed further,
and the primary perinaeal fissure remains, form-
ing the vulva ana vagina. In the male, how-
ever, the development, when normal, goes on
to a greater extent, and the sides of the opening
become so far united as ultimately to leave only
the comparatively contracted canal of the urethra
to serve as a common passage for both the
internal urinary and genital organs; and the
situation of the line of junction of the opposite
sides of the original perinaeal cleft remains still
marked out in the adult, by the raphe existing
in the median line of the scrotum. The two
lateral parts of the female clitoris unite together
into one solid body, having on its under sur-
face a slight groove or channel, indicative of
the line of conjunction of its two component
parts ; and the urethra is left to open at the
root of this iraperforated organ. In the male,
on the contrary, the two primitive halves of
the penis, consolidated together at an early
stage along the course of their upper surfaces,
come, in the progress of development, to unite
inferiorly in such a manner with one another as
to form a tubular prolongation of the pelvic
portion of the canal of the urethra, which is
gradually extended forwards along the body of
the penis and ultimately through its glans.

Many of the malformations to which the

* Comment. Med. &c. Arg. p. 534.
2 z 2

€92

HERMAPHRODITISM.

male genital organs are liable may be traced to
stoppages in the above process of development,
the character of the malformation depending
upon the period of the development at which
the arrest takes place, and varying consequently
in degree from the existence of a cloaca or
permanent primitive fissure common to the
intestinal, urinary, and generative organs,'* to
that want of closure, to a greater or less extent
in different instances, of the inferior surface of
the canal of the urethra in the body of the
penis, or in its glans, which is generally known
under the name of hypospadias. When the
development of the male organs is arrested,
immediately after the two septa respectively
separating the canals of the intestine and urethra
from the original perinaeal cleft are formed,
and consequently when this perinaeal fissure
and that running along the inferior surface of
the penis are still open, the external genital
parts often come to present at birth, and during
the continuance of life, a striking resemblance
to the conformation of the external organs of
the female, and the resemblance is frequently
rendered gi eater by the coexistence of other
malformations of the male organs. In these
cases the imperfect and undeveloped penis is
generally of small size, and, at the same time,
from being imperforate, may readily be mis-
taken for the clitoris ; the two halves of the
divided scrotum have the appearance of the
two labia externa ; the two labia externa or
nymphse are sometimes represented by the
lateral divisions of the penis forming two folds,
which run backwarks along the internal surfaces
of the split scrotum; and the cleft in the
perinaeum corresponds in situation and direc-
tion, and occasionally also in size and form,
with the canal of the vagina; this cleft is
generally lined also by a red mucous membrane
that is kept, like the natural female parts, con-
stantly moistened by the secretions of the
follicles with which it is provided; its mucous
membrane occasionally presents irregular eleva-
tions imperfectly representing the carunculse
myrtiformes; and, further, the opening of the
urethra at the root of the diminutive and im-
perforate penis serves still more to assimilate
the malformed parts to the natural conformation
of the female organs. In a number of cases,
however, the apparent analogy to the female
parts is rendered less striking by the perinaeal
cleft being small or altogether absent, the
urethral orifice at the root of the penis often
forming the only opening leading to the internal
urinary and generative parts, and the halves of
the scrotum in such instances being frequently
more or less perfectly united. Generally the
seminal ducts, and sometimes also the ducts of
Cowper's glands, are seen opening on the
surface of the urethra or supposed vaginal
canal, at a short distance from its external
orifice.

In males malformed in the manner described,
the testicles are seldom found in the divided

* See on this malformation in the human subject
(the normal form of structure in birds, &c.) Meckel
on Kloakbiltlung in his Path. Anat. Bd. i. s. 693.

scrotum at birth, but commonly they descend
into it through the inguinal rings towards the
period of puberty ; and in several instances on
record, in which the sex of the individual had
been mistaken for that of a female, the tumours
formed in the groin at that time by the organs
in their descent have been erroneously regarded
and treated as hernial protrusions. At the
same time it occasionally happens that with
the descent of the testicles, and the arrival of
puberty, the diminutive penis enlarges in size,
and the individual assumes more or less fully
the habits arid attributes of the male. In
several instances on record this change has,
under venereal excitation, appeared to occur
suddenly, and persons formerly reputed female
have thus unexpectedly found themselves pro-
vided with an erectile male penis. These
various changes are occasionally postponed for
a considerable period beyond the usual term
of puberty.

In a few rare instances one testicle only de-
scends through the inguinal ring, and occasion-
ally they both remain throughout life within the
abdomen, in or near the situation in which they
are originally developed, imitating in this ab-
normal state the normal position of the same
organs in many of the males among the lower
animals. In a number of instances in which
the testicles are thus retained within the cavity
of the abdomen, they are found small and im-
perfectly developed, and from the want of their
usual physiological influence upon the consti-
tution, the whole physical and moral character
of the malformed individual frequently presents
a considerable approximation to that of the
female, or, as we should perhaps more justly
express it, never attains the perfection of the
male, but preserves that kind of common or
neutral state exhibited by the constitution of
both sexes before the specific sexual characters
of each are developed at the time of puberty.

Numerous curious examples of mistakes
having been committed with regard to the sex
of males affected with the above species of mal-
formation have now been put on record, from
the time at which Iphis, the daughter of Ligdus,
king of Crete, was conceived to be changed
into a man by the miraculous interference of
Isis, down to the present day. Pliny, (lib. vii.
chap.iv.) has noticed several cases; and in the
treatise of Duval on hermaphrodites a number
of additional instances are collected from Livy,
Trallian, and others, some of them no doubt
invested (as most cf the details regarding her-
maphrodites in the older authors are) in much
misrepresentation and fable, but others bearing
every mark of accuracy and authenticity. In
more modern times the sexes of individuals
have often been mistaken in consequence of
this variety of malformation. Jean Chroker*
relates, in apparently the most authentic man-
ner, the case of Magdelain Mugnoz, a nun of
the order of St. Dominique in the town of
Ubeda, who was changed, as he supposes, into
a male, seven years after having taken the vows.

* Fa*. Histor. cent. i. and Arnaud, Dissertation
sur les Hermaphrodites, p. 200.

I1ERMAP11RODITISM.

693

He was expelled the convent, assumed the
male dress, and took the name of Francois.
The sequel of the story, as told by Chroker,
would seem to shew that his sexual desires be-
came extremely strong, and he is said to have
been ultimately condemned, whether justly or
not, under an accusation of rape.

Portal* quotes from Tigeon the story of a
person who was brought up as a female, and
afterwards was considered to be suddenly
changed by a surprising metamorphosis into a
male, and in citing this case Dr. Hodgkin,f of
London, mentions, on the authority of a friend,
a recent instance of an equally sudden deve-
lopment of the male sex in a previously reputed
female. Similar instances in which the proper
sex of malformed males was unexpectedly dis-
covered under the excitement of sexual passion
at the period of puberty are mentioned by Pare,
Tu!pius, and others.

SchweikardJ has recorded an instance of a
person baptized and brought up as a female,
and whose true sex was only at last disclosed
by his requesting, at the age of forty-nine, per-
mission to marry a young woman then preg-
nant by him. On examination it was disco-
vered that the penis was slender and scarcely
two inches long ; the right testicle only had
descended into the scrotum, and the urethra
opened at the root of the penis, but its orifice
was placed in such a manner that during mic-
turition the urine was thrown along the groove
or channel on the under surface of the penis, so
as to appear to issue from its anterior extremity.
The two halves of the scrotum were so far
united that they left only a small oval opening
between the anterior part of the raphe and the
roots of the corpora cavernosa. In this open-
ing the orifice of the urethra was situated.

"Dr. Baillie§ has mentioned a case which
appears to belong in all probability to the pre-
sent division. The subject of it was twenty-
four years of age. She had always passed in
society as a woman, and came for consultation
to the Nottingham Hospital on account of her
menses never having appeared ; a circumstance,
however, that had in no way affected her
health. The spurious vagina consisted of a
cul-de-sac two inches in depth. The penis
was of the size of the female clitoris, but there
were no nymphae. The labia were more pen-
dulous than usual, and contained each of them
a body resembling a testicle of a moderate size,
*,vkh its cord. The look of the individual was
remarkably masculine, with plain features, but
no beard. The mammae resembled those of a
woman. The person had no desire or partiality
for either sex.

Adelaide Preville, who had been married as
a female, died in the Hotel Dieu of Paris. In
examining the body of this individual after

* Hist, de 1'Anat. torn. ii. p. 52.

t Catalogue of Guy's Hospital Museum, part ii.
sect. xi.

• J Hufeland's Journal der Prak. Heilkunde. Bd.
xvii. No. 18.

Morbid Anatomy, p. 410, 2d edit.

death, Giraud* found that, except a perinaeal
cleft or false vagina consisting of a cul-de-sac
placed between the bladder and rectum, nothing
else resembling the female sexual apparatus
could be detected, while all the organs belong-
ing to the male sex were present

Ottof has described and represented (/g.289)

Fig. 289.

a case of the present species of hermaphroditism
in an individual whose history is remarkable.
The person had lived ten years in the state of
wedlock with three different men ; but at the age
of thirty-five an action of divorce was brought
against her by her third husband, accusing her
of being affected with some disease of the sexual
parts that rendered the connubial act on his
part extremely difficult and painful. After
some difference of opinion between the two
medical men to whose professional examination
the wife was submitted, it was at last consi-
dered that she was in reality a male, and the
case came at last under the investigation of the
members of the Royal Medical College of
Silesia, who confirmed this opinion. The im-
perforated penis (/>) was one inch and a half m
length; the perinaeal fissure (e) forming the
false vagina was, at the posterior part of its
orifice, bounded by a distinct fraenulum, but
was of a size sufficient to receive the glans of
the husband for an inch and a half in depth.
This cavity, as well as the internal surfaces of
the two lobes (« «) of the divided scrotum,
were lined with a vascular mucous membrane.
At the bottom of it the round orifice of the
urethra (d) was seen to open ; and at the same

* Recueil Period, de la Soc. de Med. torn. ii.
p. 315, or Moureau's Hist. Nat. de la Femme, t. i.
p. 243, (with a figure of the parts.)

+ Neue Seltcne Beobachtungeu zur Anatomi*,
&c. p. 123.

694

HERMAPHRODITISM.

point a hard mass could be felt, probably con-
sisting of the prostate gland ; and more up-
wards and outwards, nearly in the natural
situation of the bulb, was seen the split urethra
(c) with a row of three considerably sized open-
ings (J'f), which, under pressure and irritation
of the genital parts, gave out several drops of a
transparent mucous fluid. Otto considers these
openings as the extremities of the ducts of the
prostate and Cowper's glands, and of the semi-
nal canals. The right half of the scrotum con-
tained a small testicle about the size of that of a
boy of ten years of age ; the left testicle lay like-
wise external to the abdominal ring, and was
still softer and smaller than the right. Both
were furnished with spermatic cords. The ge-
neral configuration of the individual was strong,
muscular, and meagre ; the beard was thin and
soft, and the face, mammae, thorax, pelvis, and
extremities were evidently masculine.

Along with the preceding instances we are
inclined to classify the case of Maria Nonzia,
as detailed by Julien and Soules.* This indi-
vidual was born in Corsica in 1695, was twice
married as a female, and at last divorced in
1739 by her second husband, after having lived
sixteen years in wedlock. The penis was two
inches in length, but imperforate, and the mea-
tus urinarius was placed at its root. Two
bodies, like ordinary sized testicles, and fur-
nished with spermatic cords, were felt in the
divided scrotum ; and there was a narrow false
vagina or perinaeal canal one inch and three
lines in depth, and crossed at its upper extre-
mity by two small traversing membraneous
bridles. The character and appearance of the
person were masculine ; the visage was beard-
ed; the mammae were as fully developed as in
the adult woman, but the nipples were each
surrounded with hair.

So far as the preceding details go, they seem
amply sufficient to justify us in considering
Maria Nonzia as a malformed male ; and we
are still inclined to take this view of the case,
notwithstanding the statement inserted in the
report of Julien and Soules, that the menses
were present as in other women. For not to
insist upon the circumstance that the reporters
do not shew that they made any minute or
satisfactory inquiry into this alleged fact, and
not improbably took it upon the mere word of
the subject of the case, who was necessarily
greatly interested in maintaining^ the reputed
female character, it would be requisite, in any
such paradoxical instance, to ascertain if the
discharge actually agreed in character with the
menstrual fluid, or was not pure blood, the re-
sult of an haemorrhage from the genito-urinary
passages, or from the rectum, where, as in other
parts of the body, this form of disease frequently
assumes a periodical type. We would be in-
clined to apply even still more strongly these
remarks to the celebrated case of Hannah Wild,
detailed by Dr. Sampson.f This person had

* Observ. sur THist. Nat. sur la Physique et sur
la Peinture, torn. i. p. 18, with a plate.

t Ephem. Nat. Curios. Dec. i. an. iii. p. 323.

evidently the male genital organs malformed in
the manner mentioned with regard to the other
cases included under the present section, and
possessed all the secondary sexual peculiarities
of the male ; so that we can only receive with
great doubt and distrust the alleged existence
of the menstrual discharge, and the more so, as
this is evidently stated on the report of the
subject of the case alone, who, deriving a pre-
carious subsistence from the exhibition of his
malformations, had a deep interest in amplify-
ing every circumstance that could enhance the
public curiosity with respect to the reality of
his hermaphroditic character.

At the same time, however, it must be re-
marked that in some instances of spurious her-
maphroditism, it is found extremely difficult or
even impossible during life to determine with
precision the true or predominant sex of the
malformed individual ; and in regard to several
well-known cases on record, we find on this
point the most discrepant opinions offered by
different authors. Thus while Morand,* Ar-
naud,f and Delius} described Michel-Anne
Drouart as a male; Guyot,§ Ferrein,|| and
Caldani^I maintained that this person was a
female ; and Mertrud** regarded the individual
as an example of a real hermaphrodite.

A useful lesson of caution to us against our
forming too decided and dogmatic an opinion
in cases in which the sexual conformation ap-
pears in any marked degree doubtful, has
lately been offered in the instance of Maria-
Dorothee Duriee, or, as this individual was
named in the latter years of his life, Charles
Durge. While Metzgei ff considered this per-
son as a specimen of that kind of equivocal
sexual formation to which the designation of her-
maphroditism is truly applicable, Hufeland,JJ
Mursinna,§§ Gall, Brookes,|||| and others^
declared the sex of Duriee to be in reality
female; and Stark,*** Mertens,tft and the
Members of the Faculty of Medicine at Paris JJJ
were equally positive in regarding the indivi-
dual as merely a malformed male. The dis-
section of the body of Duriee by Professor
Mayer has, as we shall afterwards state more in
detail, shewn the sexual conformation of this
individual to consist of a true mixture of both
the male and female organs.

* Mem. de FArad. des Sc. 1750, p. 165.

t Dissert, sur les Hermaphr. p. 298.

t Frank, Sammlung. Th. viii. s. 398.
Mem. de I'Acad. des Sc. 1756, p. 71.
Ib. 1767, p. 205.
Mem. della Societa Italiana, t. vii. p. 130.

** Arnaud, loc. cit. p. 293.

tt Gericht.- medic. Abhandlungen. Bd. i. s. 177.

$t Journ. der Praktischen Heilkunde, Bd. xii.
s. 170.

§§ Journ. fur die Chirurgie, Arzneikunde, &c.
Bd. i. s. 555.

Jill Medical Gazette for October, 1836.

^f5f V°n dem Neuangekommen. Hermaphrod.
Berl. 1801.

*** Neuen Archiv. fur die Geburtshiilfe. Bd. ii.
s. 538.

tttBeschreibungdermannlichenGcschlcchtsthcile
von M. D. Durricr. Leipzig, 1802, with two plates,

#t Med. Gaz. for October, 1836.

HERMAPHRODITISM.

695

In attempting to determine the true sex in
such doubtful instances of sexual formation as
those which we have been now considering, we
are inclined to attribute very little weight to the
nature of the sexual desires of the malformed
individual, as we have already found Adelaide
Preville, the dissection of whose body shewed
him to be in reality a man, living for some
years before death in the capacity of a wife,
and the same remark might be further illus-
trated by a reference to Otto's and other cases.

A species of spurious hermaphroditism simi-
lar in character to that which we have just de-
scribed in man, is occasionally met with in the
males of our domestic quadrupeds, and has
been amply illustrated, as it occurs in these
animals, by Professor Gurlt in his work on
Veterinary Medicine. In instances of this
malformation among the animals to which we
refer, the hypospadic male penis has usually
been found of a tortuous and winding form
and of small size. In the cases in which the
fissure of the parts extends through the scrotum,
a false vagina is seldom formed, as in man, for
the scrotum in most quadrupeds lies too remote
from the perinaeum, and consequently from the
normal situation of thevasrina, for this purpose;
but in some examples this division appears to
be carried upwards into the perinaeum itself,
leaving a vaginal-like opening, in which the
urethra terminates. The testicles, as in man,
are sometimes retained within the abdomen,
and in other instances descend into the scrotum.
They are frequently small in size. The mamma
or udder seems to be often well developed.

This variety of hermaphroditic malforma-
tion has been met with in the horse by Pen-
chenati;* in the he-goat by Haller;f and in the
ram by the same author,}; and by Wagner,§
\Vepfer,|| Stark,H Gurlt,** KauwBoerhaave,ft
and A. Cooper.Jt We have seen an excellent
specimen of tins malformation in the last-
mentioned animal in the museum of Dr.
Handyside of Edinburgh. In this instance
the internal male organs are all perfect ; the
large testicles are situated in the halves of the
split scrotum ; the penis is small and imperfo-
rate, and a furrow running along its inferior
surface is continued backwards and upwards
along the perinaeum to within a short distance
from the anus, where it leads into a canal, into
which the urinary bladder and seminal ducts
open. This canal is evidently formed of the
dilated pelvic portion of the male urethra; its
orifice is comparatively contracted, but corres-
ponds in situation with the vulva of the fe-
male. We have seen a second similar case in

* Mem. de 1'Acad. de Turin, torn. v. p. 18.

t Comment. Soc. Reg. Sc. Getting, torn. i. p. 2,
tab. i.

J Ibid. p. 5, tab. i).

$ Ephem. Nat. Curios. Cent. i. ii. p. 235.

[I Miscell. Nat. Curios. Dec. i. An. iii. (1672,)
p. 255.

f Ibid. Dec. iii. Ann. v. vi., p. 669.

** Lehrbucb, p. 193.

tt Nov. Comment. Acad. Petropolit. torn. i.
(1750,) p. 315, tab. xi.

tt Catalogue of Guy's Hospital Museum, No.
2546.

the ram in the possession of Professor Dick of
the Veterinary School of Edinburgh.

There is another variety of malformation of
the male parts occasionally found in quadru-
peds, which is allied in its nature to the pre-
ceding. In this second species all the exter-
nal male sexual organs are small ; the short
penis lies, when not in a state of erection, upon
the posterior surface of the enlarged udder,
and the imperfectly developed testicles are ge-
nerally retained within the abdomen ; or, if
they have passed out of that cavity, they are
found situated in the substance of the udder.
The vasa deferentia, prostate, and Cowper's
glands are usually of their normal size and ap-
pearance. This imperfect hermaphroditic for-
mation appears to be not rare among horses,
several instances of it in this animal having
been now described by Amaud,* Gohier,f
Volmar,J Pallas,§ Virey,|| and Gurlt.H An-
sel mo** and Lecoqtt nave met with this variety
of malformation in the bull ; and Sandford JJ
has described an instance in the calf which
seems referable to the same head. Gurlt§§ also
notices the preparation of an analogous case in
the calf, as preserved in the museum at Berlin.

II. TRUE HERMAPHRODITISM.

True hermaphroditism exists as the normal
type of sexual conformation in several classes
of the vegetable and animal kingdom. Almost
all phanerogamic plants, with the exception of
those included under the class Dioecia, are fur-
nished with both male and female reproductive
organs, placed either upon the same flower,
or, as in the Linnaean class Moncecia, upon
different flowers in the same individual. In the
class Polygamia various exceptional genera are
included, that present indiscriminately upon
the same individual, or upon different indivi-
duals of the same species, male, female, and
hermaphrodite flowers, and which thus form a
kind of connecting link between the general
hermaphroditic form of phanerogamic vegeta-
bles, and the unisexual type of the monoecious
flowers, and the dioecious plants.

From anormalities in developement, these
normal conditions of the sexual type in the
different members of the vegetable kingdom
are occasionally observed to be changed. Thus,
among the Dioecia, individual plants are some-
times, in consequence of a true malformation,
observed to assume an hermaphroditic type of
structure ; or, on the other hand, in hermaphro-
ditic plants more or fewer flowers are occa-

* Arnaud sur les Hermaphrodites, p. 282.

t Mem. et Observ. sur la Chir. et la Med. Vet.
torn. i. p. 18.

$ Archiv. fur Thierheilkunde, Bd. iii. s. 292.

§ Beschaft. der Gesellschaft naturforch. Freunde
ru Berlin, Bd. iii. s. 296.

jl Journal Compl. des Sc. Med. torn. xv. p. 140.

1l Lehrbuch der Path. Anat. Bd. ii. p. 189 •, and
tab. viii. fig. 6.

** Mem. del' Acad. des Sc. de Turin, torn. ix.
p. 103. fig. 1-3.

tt Journ. Prat, de Med. Vet. 1827, p. 102.

jt Med. and Phys. Journal, vol. ii. p. 305, with
two drawings.

$$ Loc. at. p. 191.

606

IIERMAPHRODTTISM.

sionally found unisexual, in consequence of the
arrested developement of one order of their
sexual organs ; and again, though still more rarely,
from an excess of evolution, a double set of
male parts, or a double set of stamens, is seen
developed on some of the individual flowers.

In the animal kingdom we find instances of
a perfect hermaphroditic structure as the normal
form of the sexual type in the Trematodes and
Cestoides among the Entozoa, in the abranchial
Annelida, in the Planaria, and in many of the
Mollusca, particularly in the Pteropoda, and in
several families among the Gasteropoda. In
some of these animals that are thus naturally
hermaphroditic, the fecundation of the female
organs of the bisexual individual is accom-
plished by its own male organs ; but in others,
although the anatomical structure is strictly her-
maphroditic, yet the union of two, or, as some-
times happens, of more individuals is neces-
sary to complete the sexual act ; and during it
the female organs of each are respectively im-
pregnated by the male organs of the other.

In the Nematodes and Acanthocephali among
the Entozoa, and in the Cephalopoda and Pecti-
nibranchiate Gasteropoda among the Mollusca,
as well as in all symmetrically formed animals,
or, in other words, in those whose bodies are
composed of an union of two similar halves,
as in Insects, and the Arachnida, Crustacea, and
Vertebrata, the male and female organs of re-
production are placed each upon a different
individual of the species, constituting the ba-
sis of distinction between the two sexes. In
such animals a mixture of more or fewer of
the reproductive organs of the two sexes upon
the same individual appears occasionally as a
result of abnormal formation ; but the male and
female organs that coexist in these cases are
seldom or never so anatomically perfect as to
enable the malformed being to exercise the
proper physiological function of either or of
both of the two sexes. This form of true her-
maphroditism or abnormal mixture upon the
same individual of the organs of the two sexes
in the higher animals, has been termed unnatu-
ral or monstrous, in opposition to the natural
hermaphroditism which exists as the normal
type of sexual structure in some of the lower
orders of animals, and in phanerogamic plants.
The malformation itself is observed to differ
greatly, both in nature and degree, in different
cases, varying from the presence or superaddi-
tion of a single organ only of the opposite or non-
predominant sex, up to the development and
co-existence of almost all the several parts of
the two sexes upon the same individual. In
describing the malformation, we shall classify its
various and diversified forms under the
three general orders pointed out in our table,
including, 1st, lateral ; 2dly, transverse ; and
3dly, double or vertical hermaphroditism.

A. Lateral hermaphroditism. — According to
the opinion of many physiologists of the pre-
sent day, the two lateral symmetrical halves of
the body, and even the two halves of all its
single mesial organs, are originally developed
in a great degree independently of one another.
Granting this point in the doctrine of eccentric

developement, we can easily conceive how, in
the same embryo, an ovary might be formed on
one Wolffian body, and a testicle on the other;
or, in other words, how female organs might be
developed on one side, and male organs on the
other. It is the existence of such an unsymme-
trical type of sexual structure upon the two op-
posite sides of the body of the same individual,
that constitutes the distinctive characteristic of
lateral hermaphroditism.

Instances of this species of true hermaphro-
ditic malformation have been observed in many
different classes of animals, as well as in the
human subject.

Individual examples are sometimes observed
among insects, particularly among the Lepido-
ptera, in which all the different parts of the two
sides or lateral halves of the body are formed
after opposite sexual types. We shall after-
wards have occasion to notice different exam-
ples of this form of lateral hermaphroditism as
seen in the general conformation of the body,
but may here state that in two or three in-
stances such malformed insects have been care-
fully dissected, and found to present, in the ana-
tomical structure of their sexual organs, a mix-
ture of the organs of the male and female.

In a Melitcea didymus described by Klug,*
the general external characters were those of the
male, but the left eye, palpus, and antenna,
and the left sexual fang, were smaller than in
individuals belonging to this sex ; and the left
antenna was annulated with white and yellow
at the apex, while the right was of one colour.
On dissection, the various male sexual parts
were present, and they had appended to them
a free female ovary situated upon the left, and
united to no other organ.

In a Gastrophaga quercifolia dissected by
Schultz, and described by iludolphi,f the left
side appeared externally male, and the right
female, with a distinct line of separation through-
out the whole body. On dissection, Schultz dis-
covered an ovarium upon the right side, and
two testes upon the left. The oviduct of the
ovary joined the canal of the vasa deferentia
about two inches before its termination ; and
the spermatheca was connected with the com-
mon evacuating duct. The two testicles on the
left side were placed one behind the other, and
connected by a thin vessel. The spermatic
duct belonging to one of the testicles imme-
diately received, as in the Lepidoptera, the spi-
ral vessel ; further beyond, and on the opposite
side, a second vessel, which appeared to con-
sist of the rudimental spermatic duct of the
other testicle, opened into it. The oviduct of
the ovary joined the canal of the vasa deferen-
tia about two inches before its termination in
the penis, and a female spermatheca was con-
nected with the common distended evacuating
duct.J

* Froriep's Notizen, vol. x. p. 183.

t Abhandlung. der Kcenig. Akad. zu Berlin fur
1825, s. 55.

$ See also drawings of the body and genital or-
gans of an hermaphrodite Sphinx populi in Fischer's
Oryctographie du Gouvernemcnt de Moscou (Mos-
cow, 1830.)

HERMAPIIRODITISM.

697

A well-marked example of lateral herma-
phroditism among the Crustacea has been re-
corded by Dr. Nicholls.* In a lobster (Axta-
cus murinus) he found on the right side of the
body a female sexual aperture in its normal
situation at the root of the third leg, and con-
nected with a regularly formed oviduct, full of
ova. On the left side of the animal there was
a male sexual aperture placed, as usual, at the
root of the fifth leg, and connected internally
with an equally perfect testicle and spermatic
cord. The general external conformation of
the animal corresponded with its internal sexual
structure, the right lateral half of the body
presenting all the secondary characters and pe-
culiarities of the female, and the left all those of
the male ; so that if split from head to tail, (to
use Dr. Nicholls' mode of expression,) the animal
would have been perfectly female on the right
side, and perfectly male on the left.

The investigations of Sir E. Homef led phy-
siologists some years ago to believe that among
Fishes lateral hermaphroditism constituted the
natural type of sexual formation in the genera
Myxine and Petromyzon ; but the later and
more accurate observations of RathkeJ have
shewn that these species are strictly bisexual,
and that the opposite opinion had arisen from
the kidneys of the female having been mistaken
for the male testicles. Various instances, how-
ever, are on record of fishes, known to be nor-
mally bisexual, presenting from abnormal deve-
lopement a lateral hermaphroditic structure, or a
roe on one side, and a milt on the other. Such
an hermaphroditic malformation has been met
with in the genera Salrno^ Gadus,\\ and Cy-
prinus^ and in the Merlangus vulgaris,** Aci-
penser huso,-\-\- and J&SOJT liicius.H

Of lateral hermaphroditism in Birds, we have

* Phil. Trans, for 1730, no. 413, vol. xxxvi. p.
290, with drawings of the animal, and of its repro-
ductive organs.

t Phil. Trans, for 1823. Art. xii.

$ Bemerkungen ueber den Innern Bau der
Pricke, s. 119. See also additional observations by
the same author in Miiller's Archiv fur Anatomic,
&c. for 1836. Heft. ii. s. 171. The older error of
Cavolini, who supposed that he had detected two
ovaries and two testicles in the Perca marina and
Labrtu channa, (Sulla Generazioue dei Peschi et dei
Granchi, Nap. 1787,) had been previously shewn
by Rudolphi to depend upon his having mistaken
undeveloped portions of the ovaries for testicles.
(Schweigger's Skeletlose Thiere. s. 204; and Ab-
handlungen. Konig. Akad. der Wissenschaft zu
Berlin, 1825. p. 48.)

$ Commercium Litter. Norim. 1734. Hebd. 39.

|| Pipping, Vetensk. Akad. nya Handl. (1800.)
Bd. xxi. s. 33. tab. i. fig. 1. Leuwenhoeck, Ex-

rrim. et Contempl. p. 150. Eph. Nat. Cur. Dec.
Ann. i. obs. 125. Du Hamel, Traite des Poissons,
Part ii. p. 130.

U Alischer, Breslau. Sammlung. 1720, p. 645;
Morand, Mem. de I'Acad. des Sc. 1737. p. 72.
Schwalbe, Commer. Lit. Norimb. 1734. p. 305.

** Marchant, Mem. de I'Acad. des Sc. 1737. p.
12. Baster, Opusc. Subcesiva, torn. i. p. 138.

tf Pallas, Reise durch Russe, &c. Theil. ii. s.
341.

Jt Reaumur, Mem. de I'Acad. 1737. p. 51.
Starke, Eph. Nat. Cur. Dec. iii. ann. vii. and viii.
obs. 109.

one instance recorded by Bechstein,* in a
chicken that had a testicle on the right side of
the body, and an imperfect reniform ovary on
the left. The external appearance of the bird
presented a mixture of the characters of the two
sexes.

Rudolphi has referred to a second and more
ancient example of lateral hermaphroditism in
the hen, mentioned by Heide.f The case, en-
titled by the author " galli qui putabatur her-
maphroditus anatome rudis,v is so imperfectly
detailed as not to be entitled to much attention.

We have ourselves been fortunate enough to
meet with two domestic fowls that presented in
their sexual organization examples of lateral her-
maphroditism. In the first of these cases (Jig-
290) the female sexual organs were placed on the

Fig. 290.

left side of the body, and the ovary (a) and ovi-
duct (6) were in all respects apparently natu-
rally formed. On the right side, a male vas
deferens (</), of about half the normal length,

* Naturgeschichte der Voegel, &c. Bd. ii, s. 1219,
(1807).

t Anatome Mytuli : subjecta est Centuria Obscr.
Amster. 1684, p. 193, obs. 95.

6D3

IIERMAPHRODITISM.

ran up from the cloaca to opposite the origin of
the iliac vessels (c), and during this part of its
course was bent into those short transverse zig-
zag folds which characterise the structure of this
part in the common cock. (See article AVES,
vol. i. p. 354.) When it reached the middle
third of the kidney (d d), it lost this particular
form, became membranous (e\ and after pro-
ceeding upwards for about an inch, in the com-
mon course of the canal, at last disappeared.
The convoluted or contorted portion ran over a
space of about two and a half inches, and if
unrolled would have extended three or four
times that length. Its canal was about the
usual size of the same part in the perfect
cock, and perhaps at some parts even more
dilated. Its cavity was filled with a whitish
seminal-looking albuminous fluid, which at first
prevented a mercurial injection from readily
passing through it. There was not any appa-
rent vestige of a testicle. The fowl that was
the subject of this malformation possessed in
an imperfect degree the plumage, comb, spurs,
and general appearance of the cock, and when
young was considered to be a male until the
time it commenced to lay eggs, which it did
very constantly, except during the moulting
season, up to the time of its death. Its eggs
were remarked to be very large. They had re-
peatedly been tried to be hatched, but always
without success. The bird itself was never known
to incubate. It was peculiar in its habits in so
far that in the barn-yard it did not associate with
the other poultry, and at night roosted sepa-
rately from them. It crowed regularly, espe-
cially in the morning, and often attempted copu-
lation with the hens.

In the second case, the ovaries and oviduct
on the left side of the body were, as in the
former example, natural in themselves ; but
in the mesometry of the oviduct, a tube of the
size of the male vas deferens was found. This
tube, like the normal vas deferens, was thrown
into the distinctive angular folds. It ran for
about an inch and a half through the upper
portion of the mesometry, was blind at either
extremity, and admitted of being injected with
quicksilver. On the right side, there was also
a male vas deferens, marked with the characte-
ristic angular folds. The contorted portion of
this canal only stretched in this instance to
about an inch above the cloaca ; but the folds
were even stronger than in the first case, and
the tube itself was rather more dilated. Above
or anterior to this convoluted part, the tube be-
came straight and membraneous, and ran up in
this form for about two inches in its usual
track over the abdominal surface of the kidney ;
but there was not at its upper extremity any
trace of a testicle. This bird presented during
life, in a very slight degree only, the appearance
of a cock, its comb and spurs being even less
developed than in the previous case. It shewed
the same solitary habits in the poultry-yard. It
layed eggs regularly. On three different occa-
sions I had a number of them submitted to
incubation, but in none of them was a chick
produced.

In the Quadruped, Schlump* has mentioned
an instance of lateral hermaphroditic malfor-
mation. In a young calf he found on the left
side, under the kidney, a small testicle having
attached to it a vas deferens, which was con-
nected with the peritonaeum towards the abdo-
minal ring of the same side, and there became
lost in the cellular texture of the part. An ovary
and Fallopian tube, with an uterus consisting of
a single horn only, were connected to the right
side of the loins by a ligament. The neck of
the uterus lost itself in the cellular substance
beneath the rectum, and there was no vagina.
The external organs were male, but imperfectly
formed. The udder occupied the place of the
scrotum.

In the human subject several different in-
stances of sexual malformation have now been
met with referable to the head of lateral herma-
phroditism. In these cases, along with a tes-
ticle on one side, and an ovary on the other,
there has generally co-existed a more or less per-
fectly formed uterus. The external parts have
differed in their sexual characters, in some in-
stances being female, in others male, and in
others again of a neutral or indeterminate type.

In man, and in the higher quadrupeds, we
have not unfrequently exhibited to us a slight
tendency to this unsymmetrical type of sexual
structure constituting true lateral hermaphro-
ditism in the testicle of one side only des-
cending, whilst the other, in consequence of
imperfect development, remains within the
inguinal ring. In the single unsymmetrical
ovary of most female birds and some fishes,f
we see a still nearer approach to the state ; and
it is worthy of remark, that among birds at
least, the single ovary is always placed upon the
left side. In lateral hermaphrodites in the hu-
man subject, the left side also appears to be that
on which we most frequently meet with the
female type of the sexual organs. We shall
divide the following cases according to the par-
ticular sides which were respectively male and
female in them.

1 . Ovary on left side, and testes on the right. —
a. M. Sue met, in 1746, with an instance of late-
ral hermaphroditism in the human subject, in a
young person of thirteen or fourteen years of
age, whose case was the subject of a Thesis
sustained by M. Morand.J Of the internal

* Archiv. fuer die Thierheilkunde, Bd. ii, Hft. ii.
s. 204.

t In the early embryo ofbirds, the ovaries are ori-
ginally double, as pointed out by Emmert, (see Reil'c
Archiv for 1811;) and as was previously known
to Wolff and Hochstetter, (Anat. Phil. torn. i. p.
349.)

J De Hermaphroditis, Paris, 1749. This, ac-
cording to Arnaud, (p. 323,) is the same case of
lateral hermaphroditism with that described by
Lecat. If so, the latter author, (probably from
drawing his description from memory, and not,
as Morand seems to have done, from the parts
placed before him,) has stated that along with
the testicle and vas deferens on the one side, there
existed a vesicula seminalis, and that both sides
were provided with round ligaments, the one on the
male side forming probably one of the two tubes
described by Morand as arising from the testicle.

HERMAPHRODITISM.

699

genital organs, there existed on the left side
a very distinct ovary, a round ligament which
ran outwards to the groin of the same side,
and a well-formed Fallopian tube with its
usual fimbriated extremity. The other extre-
mity of the Fallopian tube terminated in
the fundus of the uterus, which occupied its
usual situation between the bladder and rectum.
On the right side, again, there was a slender
elongated testicle, which had moved forwards
to the corresponding inguinal canal, but had
not proceeded so far as to pass out of the ab-
dominal cavity. On the superior part of the
testicle was a body resembling the epididymis,
and the testicle itself sent off two tubes, which
afterwards united into one immediately before
their insertion into the uterus. The external
genital organs were those of ahypospadic male,
and during life the person had been always
looked upon as belonging to the male sex. The
perinjeal canal or vagina terminated, between the
scrotum and root of the imperforate penis, in a
very small opening, which was common to it
and to the meatus urinarius.

b. In 1 754,* a young person of about eighteen
years of age died in the Hotel Dieu of Paris ;
and in dissectinghis body, the anatomist, Varole,
found the reproductive organs malformed in the
following manner. On the right side the
scrotum contained a testicle, and the vas defe-
rens arising from it opened, not as usual into
the neck, but into the middle of the external
border of the corresponding vesicula seminalis.
On the left side the scrotum was empty ; and
internally on this side there were found an
ovary, a Fallopian tube with its fimbriated ex-
tremity, a small oval uterus without a neck and
somewhat flattened, and a broad and round
ligament, the last of which ran outwards, and
was lost in the cellular tissue of the left half of
the scrotum. The vesicula seminalis on the
right, and the imperfect uterus on the left side,
communicated by a canal of an inch and a half
in length. The external organs were male ; but
the penis was very small, had no corpus spongi-
osura, and was imperforate for half an inch at
its anterior extremity. The mammae were as
large as in women of the same age. The indi-
vidual had been regarded during life as a male.

c. In 1825 the late Professor Rudolphif de-
tailed to the Academy of Sciences at Berlin
the case of an infant who was reported to have
died seven days after birth, and whose sexual
organs exhibited the following interesting in-
stance of lateral hermaphroditic conformation.

Meckel (Reil's Archiv. Bd. xi. s. 322,) considers
Morand's and Lecat's as two different cases, and
points out that what is described as the male side
in the one, was the female in the other, and vice
versa. It is, perhaps, not unworthy of remark, that
in the coloured plate accompanying the translation
of Morand's case by Gautier, the male and female
sides have been reversed from an error in the en-
graving ; and this circumstance may have contribu-
ted to mislead Lecat in his description, provided he
happened to look to this notice of the case.

* Mem. de la Soc. Med. de Paris, torn. iv. p.
342.

t Abhandlung. Konig. Akad. dcrWissenschaft. zu
Berlin fur 1825/s. 60.

On the left side were discovered an ovary
C/g.291, «)> without a distinct broad ligament,

Fig. 291.

Fig. 292.

-C

Uterus (c) turned downwards and forwards to show
itt posterior turface and connections, Sfc.

and a Fallopian tube (6), which communi-

cated with the superior and left portion of an

uterus (c). The left side

of the scrotum (Jig. 292,

a), was empty; the right

(6) contained a testicle

(fig.1§\ ,rf) furnished with

an epididymis (e) and tor-

tuous vas deferens ( /").

Below the uterus there

was a hard flattened ovoid

body (fig. 291, g, and

fig. 293, 6), which, when

divided was found to

consist of a cavity with

thick parietes, and was

considered by Rudolph!

as the prostate gland in a rudimentary state.

The mouth of the uterus jp- 393

(fig. 293, a) terminated be-

low in the parietes of this

ovoid body, and on the

right the vas deferens (rf)

penetrated into its sub-

stance, but without open-

ing into its cavity. At the

inferior part of the uterus

there was a true vagina

(fig. 293, c), which termi-

nated in a cul-de-sac. The

anus, rectum, and other

organs were natural. The

external sexual parts were

male,

External organs.

Os uteri, vagina,
prostate, and cos
deferens.

but the penis was divided inferiorly
, c). The testicle and ovary were sup-
plied with the two usual spermatic arteries

£%.tti,M}

d. Under the present section of lateral herma-
phroditism, we may also, according to Mayer's
report, include the celebrated case of Marie
Derrier, or Charles Doerge.* This person was
baptised and brought up as a female, but at
forty years of age was persuaded to change his
name and dress to those of a man. We have
already alluded to the great diversity of opinion
which was entertained by the medical men of

* Gazette Med. de Paris (1836), no. 39. Lancet,
v. i. for 1836-7, p. 140; or London Medical Ga-
rette for October 29, 1836.

700

HERMAPHRODITISM.

Europe in regard to the true sex of this indivi-
dual. Even the different parts of his body were
at one time referred to the male type, and at
another time, and by other persons, to the fe-
male. The pelvis was the only part that was
generally considered as decidedly female, yet
the inspection of the body after death by Pro-
fessor Mayer shewed that even in this respect
all were in error.

Of the female sexual organs there existed an
uterus, vagina, two Fallopian tubes, and an
ovary ; and of the male, a testicle, and prostate
gland and penis. The uterus was placed in
its normal situation between the urinary bladder
and rectum, but with its fundus directed in some
degree to the left. The organ was extremely
narrow, and two and a half inches in length.
The cavity of its cervix presented on its inner
surface some slight folds, but would scarcely
admit a quill ; the cavity of its fundus was
nearly half an inch across. The small canals of
two Fallopian tubes opened into the fundus
uteri. Their abdominal extremities were shut,
but the corpora fimbriata were present. Near
the extremity of the right Fallopian tube, which
was four inches and four lines in length, a small
flattened almond-shaped body was placed, which
on examination proved to be distinctly a testi-
cle. It was completely enveloped in perito-
naeum, and received a cord composed of muscu-
lar fibres, and of a spermatic vein and artery.
Its internal structure was yellow and filamen-
tous, like that of the testicle, and its seminiferous
tubes could be easily separated. The left Fallo-
pian tube was an inch shorter than the right ;
and a little outside and behind its abdominal
extremity another small flattened body was
found inclosed in the peritonaeum. It resembled
an ovary rather than a testicle. Its tissue was
composed of small granules conglomerated
together. The penis was two inches and nine
Jines in length, and was for the greater part
concealed underneath the mons veneris. During
life it was capable of erection, and was then
elongated to more than three inches. The pre-
puce covered only half the glans. There was
not any corpus spongiosum. A fossa or groove,
representing an urethral canal divided inferiorly,
ran along the under surface of the penis. The
two folds of skin forming the sides of the
groove separated from each other posteriorly,
and might be compared to nymphae. Towards
the root of the penis, by uniting inferiorly with
a puckering of the skin of the labia majora or
divided halves of the scrotum, they formed a
circular orifice not larger than a quill, having
some bodies, supposed to be vestiges of the ca-
runculae myrtiformes, at its lower edge, and lead-
ing to a short vestibule, or common canal, into
which the urethra, surrounded by a firm but
small prostate, entered from above, and the va-
gina, encircled at its entrance by a vascular
ring of varicose veins, opened from below. The
vagina was two inches and eight lines in length,
and only ten lines at its greatest breadth. Its
inner surface was somewhat wrinkled an-
teriorly, but smooth behind. It terminated
above in a kind of spongy isthmus representing
the blind orifice of the uterus, and from four to

six lines in length. The diameters and form of
the pelvis were, on dissection, found to be most
evidently masculine.

The general character of Doerge was a mix-
ture of the male and female type. When be-
tween twenty and thirty, he had been examined
by d ifTerent medical men inGermany , France, and
England, and, as we have already mentioned,
the most contradictory opinions were offered
upon his real sex. The breasts were not
much developed, and there was no distinct
mammary glandular structure. His stature was
small (five feet). As he had advanced in
age, his voice had become more firm and
grave, and a slight trace of beard had ap-
peared ; but his head and face presented the
aspect of that of an old woman. His neck was
short, and the thyroid cartilage did not project
much : his chest was fat and full. During the
last few years of his life he was subject to
epistaxis and haemorrhoids, but did not present
any trace of sanguineous discharge from the
genital organs, — a phenomenon which was
alleged to have manifested itself three times
during his twentieth year.

The right hemispheres of the cerebrum and
cerebellum, particularly that of the latter, were
smaller and less developed than the left, and the
left side of the occiput was externally more
prominent than the right. He is stated by
Professor Mayer to have shewn a certain pred i-
lection for females, without, however, feeling
any sexual desire.

2. Testicle on the left, and ovary on the
right side. — An instance of malformation of the
reproductive organs minutely described by
Maret,* and which is in all its more essential
anatomical points an example of lateral herma-
phroditism, may be included under this head.

a. The subject of the case (Hubert Jean
Pierre) died in the hospital at Dijon in 1767,
at the age of seventeen. On the left side a
perfect testicle was discovered with its usual
spermatic vessels, vas deferens, and vesicula
seminalis, all occupying the natural situation
in which they are placed in the male adult.
The vesicula seminalis contained a fluid of the
colour and consistence of semen. On the right
side an oblong cystic tumour was found lying in
the iliac fossa, and stretching outwards into the
inguinal region. On opening it a quantity of
reddish limpid fluid escaped, and then the solid
contents of the tumour were seen to consist of a
somewhat flattened body, that gave off from the
upper part from its right side a short Fallopian
tube ; and at the fimbriated extremity of this
tube an ovary of the natural size, consistence,
and figure, was situated. The roundish shaped
body to which the tube was attached was about
an inch and a half in its greatest, and an inch in
its smallest diameter. It contained in its
centre a small cavity continuous with that of
the tube, — a circumstance, which, along with the
structure of its walls, left little doubt that the
body itself was an imperfectly formed uterus.
No other opening except that of the tube could
be traced into its cavity. Its external surface

* Mem. de 1' Acad. dc Dijon, t. ii. p. 157.

HERMAPHRODITISM.

701

was attached to the ovary by a kind of ligament.
On this same side of the body (the right) there
existed also a vesicula semmalis, but smaller
and more shrivelled than that on the left. It
gave off a vas deferens, which became gradu-
ally smaller as it was traced backwards, and at
last disappeared altogether without being con-
nected with any structure resembling a testi-
cle. In regard to the external organs of
generation, the penis was four inches long
and imperforate, but in all other respects per-
fectly formed. It possessed a corpus spongi-
osum, which does not exist in the female
clitoris. On raising the penis, it was observed
to cover a large fissure, the sides of which
resembled the labia of a female. In the left
labium or left half of the scrotum the testicle
already alluded to was placed, but there was
none in the right. When the labia were
separated, t\vo red spongy bodies were seen,
resembling the nymphae in appearance, and
seemingly consisting of the sides of the split
urethra. Between these bodies and at their
upper part, the urethra opened as in the female ;
while below there was a very narrow aperture
covered by a semilunar membrane, and pre-
senting on one side of its entrance a small ex-
crescence somewhat resembling in figure a
caruncula myrtiformis. This orifice led into
a membranous canal or cul-de-sac an inch in
depth, and half an inch in diameter. On the
lower part of this canal the verumontanum and
orifices of the seminal ducts of both sides were
discovered.

During life Pierre had been considered a
male, but was not known to have shown
any partiality for the female sex. His counte-
nance was more delicate than what we ordi-
narily see in the male sex. There was no
beard on the face ; the larynx was not enlarged
as in man ; and the mammae, each of which
was furnished with a very large areola, were of
a moderate size and roundish form. The con-
figuration of the lower part of the body was
more decidedly masculine, and there was
none of that enlargement of the buttocks and
projection of the thighs, from the increased
width of the pelvis, which is observable in
young females.

In this case we have on the left side of the
body male sexual organs, consisting of a per-
fect testicle, vas deferens,and vesicula seminalis.
On the right side, again, we have a female ovary
and Fallopian tube with a rudimentary uterus,
together with an imperfect male vesicula semi-
nalis and vas deferens.

Arnaud mentions a very imperfect form
of lateral hermaphroditism as having been re-
cognised by M. Boudou, surgeon to the Hotel-
Dieu of Paris, on the person of a monk who
died in that hospital in 1726. The external
genital parts were those of a hypospadic male.
In one of the halves of the scrotum a testicle
was found ; the other was empty. The seminal
canals and vesiculae seminales on the side on
which the perfect testicle existed were natural
in their course and situation. Those of the
opposite side lost themselves between the

bladder and rectum in a small body, which, in
M. Boudou's opinion, was a shrunk uterus.*

Among the preceding cases of lateral herma-
phroditism in the human subject, there are four
in which the left side, and one only in which
the right was the female. In the last instance
quoted from Boudou the respective sides on
which the male and female organs were placed
are not stated by Arnaud.

B. Transverse hermaphroditism. — In the
variety of hermaphroditic malformation which
we have last considered, we have found upon
the same individual the reproductive organs of
one side disagreeing in their sexual type from
those of the other. In the present division we
have a similar sexual antagonism following a
different direction ; for supposing the internal
sexual apparatus to be divided from the
external by a transverse line, we have, in trans-
verse hermaphroditism, on each side of this
partition, organs of an opposite sexual type :
in other words, the organs of reproduction
(in the more correct sense of the word) or the
internal sexual organs do not, in the present
species of hermaphroditism, correspond in type
with the organs of copulation, or the external
sexual parts, — a circumstance the occasional
occurrence of which tends to shew that these
two portions of the generative apparatus are in
some degree independent of one another in
their normal development and existence, and
consequently also in their abnormal formations.

Transverse hermaphroditism varies in its
character according to the relative positions
occupied by the co-existing male and female
oigans ; the external organs, or all those ex-
terior to the supposed transverse line, being
sometimes female, and the internal male, and
vice versa.

I. Transverse hermaphroditism with the
external sexual organs of the female type. — In
the cases included under this division, the ex-
ternal genital organs consist of a clitoris,
vagina, and uterus ; the uterus is often rudi-
mentary, and sometimes altogether absent and
replaced by the male vesiculae seminales. The
male internal organs are the testicles, generally
small and imperfectly developed, and placed
either within or without the abdomen, with
vasa deferentia terminating in the uterus and
vagina.

This variety of sexual malformation has been
repeatedly observed among our domestic
quadrupeds, particularly among black cattle.
Mr. John Hunter, in an essay read before the
Royal Society in 1779, and published in their
Transactions,! and in his Observations on the
Animal Economy, shewed that, (as had been
long known among agriculturists,) when among
black cattle the cow brings forth twin calves,
one of them a male, and the other apparently
a female, the male is a perfect bull calf, but the
female, while it has all the external marks of
a cow-calf, as the teats and udder, is still, with
a few exceptions, imperfectly formed in its

* Arnaud, loc. cit. p. 283.
t Vol. Ixix.

702

HERMAPHRODITISM.

internal sexual organs, and very generally pre-
sents a mixture of the organs of the two sexes in
various degrees. Such hermaphroditic twin
cattle have long been distinguished in this
country under the name of free-martins. In
some exceptional cases only have they been
observed capable of breeding; and generally
they shew no sexual desire for the bull, or the
bull for them. In appearance they resemble
the ox or spayed heifer, and have a similar, or
still greater disposition to become fat under
the use of good food.

In the paper to which we have referred, Mr.
Hunter has described the dissection of three
free-martins : and one of these seems to belong
to our present division of female transverse
hermaphroditism. The clitoris and external
parts appear to have been strictly of the female
type, and there was a small udder with four
teats. The vagina terminated in a blind end a
little beyond the opening of the urethra, and
from this point the vagina and uterus were im-
pervious. The uterus at its superior part
divided into two horns, and at the termi-
nations of these horns, not ovaria, but bodies
resembling the male testicles were found. These
bodies had not a perfect internal structure like
that of testicles, but resembled these organs in
so far that, 1st, they were nearly as large as
the male testes, and much larger than the
female ovaries ; 2nd, they were supplied with
tortuous spermatic arteries like those of the bull
or rigdil ; and 3d, cremaster muscles passed
up to them, as in rigdils, from the abdominal
rings. There were two small vesiculae semi-
nales placed behind between the bladder and
uterus, with their ducts opening into the
vagina. Nothing, according to Mr. Hunter,
similar to the vasa deferentia was present;
but Gurlt is inclined to believe that the parts
which Mr. Hunter has described as the horns
of the uterus were really the deferent vessels.

Professor Gurlt* has himself given, from a
preparation in the Museum of the Berlin
Veterinary School, the accompanying sketch of
the malformed sexual organs of a five-year old
free-martin, (jig. 294,) which presents to us an
illustration of Mr. Hunter's supposed mistake,
at the same time that it affords a well-marked
example of transverse hermaphroditism. The
detail of the anatomical peculiarities of the
case has been unfortunately omitted by the
author, but from the short explanations appended
to the drawing, it appears that the clitoris (a)
and external pudenda (6) were perfectly
feminine, and that the vagina, short and funnel-
shaped, terminated at its superior contracted
extremity in two vasa deferentia (c c c), which
were carried upwards in a duplicature of peri-
tonaeum (d d) resembling the broad ligament,
until they joined the unrolled and lengthened
epididymes (e e} of two small testicles (j[f)
placed in the position of the ovaries. Near the
junction of the vagina and vasa deferentia
bodies resembling the male vesiculae seminales

* Lehrbuch der Pathol. Anat. d. Saug. Th. Bd.
ii. S. 186.

Fig. 294.

(g g) and Cowper's glands (h A) were situated,
and the urethral canal (i) opened into the
vagina and was shorter than it usually is in the
cow.

We have found upon a free-martin cow a
state of the sexual apparatus very much re-
sembling that figured in the above case by
Professor Gurlt. The two vasa deferentia, as
they ran in the duplicature of the peritonaeum,
had very much the appearance and shape of an
imperfectly developed uterus. The vesiculae
seminales were large ; the vasa deferentia were
quite impervious throughout their whole course ;
and the bodies placed at their abdominal ex-
tremities were large, but of so indeterminate a
structure as not to enable us to pronounce them
to be either true testicles or ovaries.

M. Geoffrey St. Hilaire published in 1834
a very distinct case of an hermaphroditic goat
which had two male testicles and epididymes
with a two-horned uterus and female external
parts.* M. Isidore St. Hilairef mentions a
nearly analogous case in the same animal,
and quotes a third from Bomare which was ob-
served upon a deer.J

* Nouv. Ann. du Museum d'Hist. Nat. t. ii. p.
141.

t Histoiredes Anomalies, t. ii. p. 128.
j 'Journ. de Phys. t. vi. p. 501.

IIERMAPHRODITISM.

703

To the present division of transverse herma-
phroditic malformation with external female and
internal male organs, we may probably also
refer the case of the hermaphrodite dog de-
tailed by Sir E. Home,* and three instances in
the sheep described by Ruysch,f Herholdt,J
and Gurlt.§ In all these instances imperfectly
developed testicles were situated either within
the abdomen or without it upon the udder, at
the same time that the external parts exhibited
in a more or less marked degree the peculiarities
of the female sex ; the vagina was, however, nar-
rower, and the clitoris more developed than in
the perfectly formed female ; and in the dog
mentioned by Home, this latter organ was very
large, being three quarters of an inch long, and
half an inch broad, but still it could not pro-
perly be considered as an imperfect penis, since
the bone, which forms the distinguishing mark
of that organ in the dog, was wanting.

Few well-marked instances of transverse
hermaphroditism with external female organs
have been hitherto described as observed in the
human subject, unless we regard as an approach
to it the numerous cases, already referred to, of
spurious hermaphroditic malformation in the
male from hypospadic division of the urethra,
scrotum, and perinseum.

«. In his essay on hermaphroditism, how-
ever, SteghlehnerU has detailed at great length
the particulars of a case belonging to the present
variety, which he met with on the body of a
woman who died of phthisis at the age of
twenty-three. The external sexual organs were
all of the female type and in general well
formed, though the clitoris and nymphre were
perhaps smaller than natural, and the orificium
vaginae was rather contracted and half shut up
by a hymen. The fossa navicularis was very
distinct, and the vagina normally situated, but
extremely short and narrow. Its internal sur-
face presented an appearance of transverse and
longitudinal rugae, but its upper extremity
formed a blind sac, and no traces could be
found beyond it of the uterus, nor indeed any
vestiges whatever of the other internal female
organs, the ovaries and Fallopian tubes. On
more minute examination a testicle with its
spermatic cord was found in each inguinal
region, placed outside the external ring, and
surrounded with their cremaster muscles and
vaginal coats. The testicles were flaccid and
small, but their internal structure and that of
their epididymes was natural ; and the slender
pervious vasa deferentia arising from them
entered the abdomen, descended into the pelvis,
and were joined behind the urinary bladder by
two vesicula? seminales of considerable size.
Their common ejaculatory ducts opened into
the vagina. The form of the thorax and pelvis,
and of the body in general, was feminine ; and

* Phil. Trans, for 1795, p. 157. Comp. Anat.
iii. 323.

t Thesaur. Anat. viii. n. c. iii. tab. 115.

t Viborg's Sammlungs fuer Thierartze (1797.)
s.25.

$ Lehrbuch, &c. Bd. ii. s. 186. tab. ix. 2. and
xxii. s. 2,

|| Tract, tie Hermaphr, natura, p. 120.

the mammae and nipples were well developed,
but the larynx was rather more protuberant than
in females, and the voice approached in tone
to that of a man. There had never been any
menstrual discharge, but the periodical moli-
mina indicative of its appearance were said to
have been observed regularly. There were
some haemorrhoidal tumours situated around
the anus.

b. If possible a still more perfect example
of the present variety of transverse hermaphro-
ditism in the human subject has lately been
observed at Naples. The malformation occurred
in the person of an individual Maria E. Arsano,
who died at the age of eighty in one of the
pauper charities at Naples, and who had passed
through life as a female and been married as
such. No suspicion of the malformation
existed during life, and it was only at first
accidentally discovered in preparing the dead
body for demonstration in the anatomical
theatre of Professor Ricco, who afterwards
carefully dissected the malformed parts in com-
pany with Professors Sorrentino and Grosetti.
We have taken the following account and
sketches from Ricco 's published description of
the case.*

The external organs of generation were those
of the female in their natural or normal state,
consisting of the mons veneris with a scanty
quantity of hair (fig. 295, a) ; of the labia ex-

Fig. 295.

terna (fig. 295 & 296, b b) naturally formed, and
the nymphae (fig. 295 & 296, d d) ; of the
clitoris Cj?g.295 & 296, c), which was perfectly
imperforate, and of the ordinary size of the
same organ in the adult female ; of the orifice
of the urethra (fig. 295 & 296, e) situated be-
low the clitoris; and of the os vagina (fig.
295 & 296,/J, which was of the usual size and
diameter. Altogether the aperture of the vulva
was natural. The canal of the urethra was
of the usual length, as seen at u in the section

* Cenno Storico sa di un Neutro-Uomo, p. 5, 7.

704

HERMAPHRODITISM.

of the pelvis represented in jig. 296, in which
s marks the divided symphysis pubis, and p the

Fig. 296.

peritonaeum. The os vaginae shewed no vestiges
of the membrane of the hymen, or, in other
words, was without carunculae myrtiformes.
The canal of the vagina (fig. 296, v) was about
two inches long, but without rugae, and it ter-
minated internally in a completely blind extre-
mity or cul-de-sac. The uterus was entirely
wanting, as were also the Fallopian tubes and
uterine ligaments.

The internal organs of reproduction were,
on the other hand, completely male. The two
testicles (fig. 295, g g) were situated in the
region of the pubis, and were scarcely clear of
the inguinal rings. They were of the usual
ovoid figure, and natural in size. They had
internally the structure of the tubuli seminiferi,
but it was not well developed. The spermatic
cords were quite normal both in regard to their
composition and the origin and course of their
bloodvessels. The right spermatic artery (fig.
295, 1) arose, as usual, from the renal, and
the corresponding vein (w), after forming the
pampiniform plexus (7c), opened into the vena
cava inferior ; while on the left side the artery
(/) arose from the aorta, and the vein (m) ter-
minated in the left emulgent. The epididymes
of the testes were also of the usual vermiform
figure, and the corresponding vasa deferentia
(fig. 295 & 296 h h) coursed towards their vesi-
culae seminales (fig. 296, j), and terminated in
an attenuated membranous expansion without
any external aperture or ducti ejaculatorii.
The vesiculae seminales (see the left one ; in
fig. 296) were placed between the urinary blad-
der (o) and rectum (r) ; they were smaller and
more shrunk than those of the adult male,
though certainly they preserved their naturally
oblong form. Their internal hollow or tubular
structure was indistinct. The prostate gland
was not present. The urinary bladder (o) and
ureters (n n), the rectum (r), and the other
intestinal viscera, with the abdominal blood-
vessels (s, the aorta, t, the vena cava, fig. 295)
seem to have been all quite natural.

The head of the above individual was of the
usual size, the neck long, and the stature
ordinary. The periphery of the thorax was so

expanded as almost to equal that of the male,
notwithstanding the presence of well pro-
nounced mammae. The face, although entirely
free from hair, had yet neither the expression
of that of a female nor of a male, but shewed
more of that mixed character which is seen in
the eunuch. The pelvis was altogether that of
a male in its form and dimensions, and the
limbs were perfectly masculine. According to
information collected after death, the voice was
deep, and the temperament strong and firm.
Though there was never any menstruation, yet,
from being constantly employed in domestic
occupation, the mental character was feminine,
and the married state had been willingly entered
into.

2. Transverse hermaphroditism with the ex-
ternal sexual organs of the male type. — The
male organs that are present consist of the
penis, which is provided with a regular formed
prepuce, glans, corpora cavernosa, and corpus
spongiosum, with the urethra perforating it,
and of the prostate gland, verumontanum, &c.
The co-existing female organs are the ovaries,
the Fallopian tubes with their infundibula, and
the uterus.

We are not aware of any recorded instances
of this variety of hermaphroditic malformation
among the lower animals. We have already,
under the head of spurious hermaphroditism
in the female from enlargement of the clitoris,
&c., mentioned several cases, in which, from
excessive developement, the external organs in
women had assumed some of the characters of
the corresponding parts in man ; but the two
following cases described by Professors Esch-
richt of Copenhagen, and Bouillaud of Paris,
present instances of malformation in which the
more exterior sexual organs were all formed
upon the male, and the internal upon the
female type.

a. The subject of the case described by
Eschricht* was a twin child that died very
shortly after birth, and in whom the external
sexual organs were of the male type, and the
internal female. The penis (fig. 297, a) and
scrotum (/>) were well developed, but the usual
raphe seen upon the latter was absent. The
urethral canal of the glans and body of the
penis was pervious throughout, and admitted
of a sound being easily passed into the bladder.
The glans was remarkably thin and slender.
The prepuce could be easily pushed back. No
testicles could be felt in the scrotum, and in-
ternally there was an uterus with Fallopian
tubes and ovaries. The uterus (c) was about
an inch in length, and had the general form
presented by this organ in female infants. It
contained a cavity marked with rugae, but had
no orifice inferiorly, nor any vagina attached
to it. Its blind or imperforate neck was firmly
attached to the posterior walls of the urinary
bladder (g), while its fundus was directed very
obliquely downwards and over to the left side.
From the left side of the fundus of the uterus
a twisted Fallopian tube (d) proceeded, having

* Muller's Archiv fuer Anatomic, &c. 1836,
Heft ii.

IIERMAPHRODITISM.

705

Fig. 297.

large vessels was abnormal. The other twin
child was well formed and lived.

l>. The case of transverse hermaphroditism
observed by Bouillaud* was even still better
marked than that of Eschricht. Valmont, the
individual who was the subject of it, died in
one of the hospitals of Paris of the epidemic
cholera. He was a hatter by trade, and had
been married as a male. No further particulars
of his history or habits could be obtained.
-The following was found by MM. Manec
and Bouillaud to be the state of the external
and internal sexual organs.

Externally there was a penis (Jig. 298) of a

Fig. 298.

well developed fimbriae (e) at its abdominal
extremity, and the broad ligament or fold of
peritonaeum along which it ran contained an
oblong soft, body (i), (which Eschricht considered
as distinctly an ovary,) and a round ligament
that took its course through the inguinal canal
of the same side. On the right side an ovary
(&) and Fallopian tube (/) were likewise dis-
covered, but they were displaced and separated
from the body of the uterus. The ovary lay in
the iliac region, and above it and towards its
outer side was placed the fimbriated extremity
of the corresponding Fallopian tube. The tube
presented towards this extremity a vesicular
swelling of the size of a small pea, which
admitted of being inflated and filled with
quicksilver through a small opening between
the fimbriae. Below this it was impervious,
and apparently diverged off into two prolonga-
tions, one of which (the round ligament) passed
down into the inguinal canal, and the other
crossed over with a fold of peritonaeum to where
the rectum and urinary bladder were preter-
naturally connected together. Professor Jacob-
son suggested that this latter part was a rudi-
ment of the right half or horn of the uterus.
It may perhaps, however, be more properly
regarded as the commencement of the right
Fallopian tube, and in this case it would, if
continued onwards, have been joined to the
neck of the uterus, — an arrangement which
would be quite in accordance with the usual
deep and displaced origin of one of the tubes
in instances of congenital obliquity of the
uterus.

The child was malformed in other respects
also. The anus was imperforate, and the
rectum (») opened into the urinary bladder,
which was very contracted. The kidneys (m)
were irregularly formed, and lay near the pro-
montory of the sacrum. There was an acces-
sory spleen, and the formation of the heart and

VOL. II.

medium size, terminating in a regularly formed
glans (a), and furnished with a prepuce (6).

The urethra (fig. 299, b b) opened on the
inferior side of the glans (jig. 298 & 299, a).
In its course from this point backwards to the
bladder, it perfectly resembled the urethra of the
male, and was surrounded at its origin by a well-
formed prostate gland (J?g.299, k &)• Cowper's
glands were also present (fig. 298, d). The
verumontanum or caput gallinaginis was dis-
tinct, as well as the orifices of the prostatic
follicles; but the usual openings of the seminal
canals could not be found. The corpus spon-
giosum urethras (fig. 298, g) and the corpora
cavernosa (fig. 299, m m) were as well deve-
loped as in the perfect male subject. The
scrotum was small, and did not contain any
testicles; it presented on its middle a line or
raphe extending from the prepuce to the anus,
and which was harder and better marked than
it usually is upon male subjects. The various
muscles of the male perinaeum (fig. 298, c c)
were present, and very perfectly formed. The
constrictores urinae muscles (e) were particularly
long and thick.

In the cavity of the pelvis two ovaries (fig.
299, d d), similar in form and structure,
according to M. Manec, to those of a girl of
fifteen or sixteen years of age, or (to adopt

* Journ. Hebdom. cle Med., torn. x. p. 466.
" Exposition Raisonnee d'un cas de nouvelle et
singuliere variete d'hermaphrodisme observee chcz
1'hoinmc."

3 A

706

IIERMAPHIIODITISM.

M. Bouillaud's statement) two bodies in some
sort fibrous, and perhaps intermediate in
their structure between ovaries and testicles,
•were found along with two Fallopian tubes
(jig- 299, g g), having each a fimbrialed ex-
tremity at one end, and opening by the other
into the cavity of an uterus (//) which occupied
the usual situation of that organ in the female,
and opened inferiorly into a kind of vagina (e).
The internal surface of the uterus showed the
usual arborescent wrinkles of this organ in the
unimpregnated state ; the os tincre was regularly
formed ; the vagina was about two inches long,
and of a middle size, and presented internally
numerous ridges, such as are met with in
virgins. This canal, when opposite the neck
of the bladder at /', became much contracted,
and was continued downwards in the form of
a small tube to the membraneous portion of
the urethra, into which it entered by a narrow
orifice. The broad ligaments of the uterus were
normally formed ; the round ligaments passed
through the inguinal canal accompanied each
by an artery larger than that of the correspond-
ing one in the female sex.

The external appearance and form of Vahnont
are described by M. Bouillaud as having been
intermediate between those of the male and
female sex. The stature was short ; the mam-
mary glands and nipples were well developed;
the face was bearded ; but the general phy-
siognomy was still delicate. The body was fat;
the hands and feet were small ; the pelvis was
shallow ; and the haunches were wider than in
a well-formed man.

C. Double or vertical hcnnaphroditisw. —
In the two divisions or orders of true herma-
phroditism which have been already considered,,
we have seen re-united upon the body of the
same individual more or fewer of the organs
of the two sexes, but so arranged as not neces-
sarily at least to present the occurrence of actual
duplicity in any of the corresponding male
and female parts. In both lateral and trans-
verse hermaphroditism the type of the sexual
apparatus is in fact single in so far that it con-
sists> in almost all cases, in the presence at
one part of an organ or organs differing in
sexual type from those that are present at other
parts, without there necessarily co-existing at
any one point the two corresponding male
and female organs. In the present or third
variety, however, of true hermaphroditism, we
come to a tendency to actual sexual duplicity >
in the co-existence of two or more of the ana-
logous organs of the two sexes upon the same
side, or in the same vertical line of the body.
For, supposing we viewed, either from before
or behind, the reproductive organs belonging
to the two sexes all stretched out upon the
same erect plane, so that their corresponding
organs should be exactly superimposed upon
one another, — as the two female ovaries upon
the two male testicles, the Fallopian tubes upon
the vasa deferentia, the uterus upon the vesi-
culae seminales and prostate gland, &c.,' — we
should find in vertical or double hermaphro-
ditism more or fewer of those analogous organs
of the two sexes that were thus placed upon
one another, and that consequently lay in the
same vertical line, or upon the same side of the
body, co-existing together at the same time
upon the same individual.

Double, vertical, or complex hermaphro-
ditism differs much in variety and degree in
different cases, from the imperfect repetition of
two only of the corresponding organs of the
male and female upon the same body, to the
reunion or co-existence of almost all the genital
organs of both sexes upon one individual.

For the purpose of contrasting and collect-
ing together as much as possible the more ana-
logous cases, we shall arrange the instances of
double hermaphroditism under three genera
or divisions; tliejirst including cases in which
there co-existed a female uterus and male vesi-
culae seminales, with a general female type;
the second, those in which a female uterus,
occasionally provided with Fallopian tubes,
was added to an organization that was in other
respects essentially male ; and the third com-
prehending all examples in which ovaries and
testicles are alleged to have been repeated toge-
ther upon one or both sides of the body. Other
divisions of double hermaphroditism may be-
come necessary under the accumulation of new
varieties of cases, but we believe it will be
possible to arrange all the instances hitherto
recorded under one or other of the above di-
visions. In classifying and describing these
instances we shall in the meanwhile offer no
observations on the probable anatomical mis-
takes that have been committed in the exami-

IJERMAPIIRODITISM.

707

nation of individual cases. We reserve this
important subject for special consideration
under a separate head, where we shall endea-
vour to shew the numerous sources 'of error
with which the observation of individual ex-
amples and varieties of complex hermaphro-
ditism is beset.

1. Jfale vesiculfc seminales, $c. superadded
to organs of a female sexual type. — In this first
genus of double hermaphroditism we find two
female ovaries, or bodies resembling ovaries,
and an imperfect uterus co-existing with two
male vesiculae seminales, which are occasion-
ally accompanied also with rudiments of the
vasa deferentia. One of the free-martins de-
scribed by Mr. Hunter* is referable to this
variety of double hermaphroditism. The ex-
ternal genital organs and mammae resembled
those of the cow, but were smaller in size.
The vagina, beyond the opening of the urethra
into it, was, with the uterus itself, impervious.
The imperfect uterus divided into two horns,
at the end of which were the ovaria. On each
side of the uterus there was an interrupted vas
deferens broken off in several places ; and be-
tween the bladder and vagina these vasa de-
ferentia terminated in two vesiculoe seminales.
The ducts from the vesiculae and the vasa de-
ferentia opened into the vagina. In this in-
stance we have all the female organs present,
but imperfect in their development ; and at the
same time there is superadded to them a tubu-
lar structure, formed, according to Mr. Hun-
ter's opinion, of the male vesiculae seminales
and vasa deferentia.

We have met with a free-martin cow, in
which upon dissection we found an arrange-
ment of sexual parts very similar to that
described in the preceding case. The uterus,
however, though small, was pervious for a
distance of some inches above the vagina;
and at the abdominal end of each blind Fal-
lopian tube there was a dilated sac of con-
siderable size lined by peritonaeum, and open-
ing into the abdominal cavity by a small orifice.
These sacs we considered as abortive attempts
at the formation of the fimbriated extremities.
The imperfect bodies which we considered as
testicles were placed near the cavities which
we mention, in the situation of the ovaries.
They were small in size, and of an oblong
shape. On a section being made of them,
they shewed internally a kind of dense ho-
mogeneous yellow tissue, dotted or crossed
with strongly marked white lines. The vasa
deferentia could be traced along each side of
the uterus in the form of broken dense cords.
The vesiculae seminales were large and partially
hollow, and near them on each side there was
an oblong body of considerable size, having
the appearance of Cowper's glands. The tubes
from them, and from the vesiculae seminales,
opened near the os tincae into a vagina of nearly
the usual size.

2. An imperfect female uterus, fyc. super-
added to a sexual organization essentially male.

* See An. Econ. p. 64. Mr. Well's free-martin.

— In the cases included under this second
division of double hermaphroditism there exist
a male testicle, or testicles, vasa deferentia,
and vesiculae seminales, along with a female
uterus. The uterus occupies its normal situ-
ation between the bladder and rectum. It is
sometimes defectively developed, and of a
membranous structure; and occasionally it is
not provided with Fallopian tubes, or, in the
quadruped, with cornua. The cavity of the
uterus communicates with a vagina that either
opens in its usual situation externally, or, as
happens more frequently, joins the male ure-
thra. In some cases the vagina is wanting,
and the uterus opens directly into the canal of
the urethra.

Several cases of sexual malformation in the
ram, goat, and dog referable to this variety of
double hermaphroditism have been described
by different authors; and various analogous
instances have now also been observed in the
human subject

In a lamb described and delineated by Mr.
Thomas,* all the external parts were male, but
the scrotum was divided or hypospadic. In-
ternally there were two perfect male testicles
in the situation of the ovaries, with their epidi-
dymes, vasa deferentia, and vesiculae seminales ;
and a well-formed two-horned uterus furnished
with its usual ligaments, and with Fallopian
tubes that ran up and terminated in a tortuous
convoluted manner upon the testicles. The
body of the uterus possessed the common rugose
structure, but the horns were lined by a smooth
membrane without their usual glandular bodies
internally. At the anterior extremity of the
fundus uteri, a thick semilunar valve, which
seemed to correspond to the os tincae, passed
across and hardly allowed a fine probe to be
entered over its upper edge. The vagina
scarcely existed, and formed only a short
smooth pouch terminating below in a cul-de-
sac. The male vesiculaa seminales and vasa
deferentia entered the male urethra in their
normal situation at the caput gallinaginis.

Gurltf has described and delineated the
sexual parts of a goat in which all the inter-
nal male genital organs, with the exception
of Cowper's glands, were found (jig. 300).
There was also present an uterus (e) provided
with long but narrow and curved cornua (ff),
that accompanied the vasa deferentia and tes-
ticles through the abdominal rings, and ended
blind at the epididymes. The testicles lay
externally upon the udder, which was of con-
siderable size. The scrotum was absent; the
penis (g) was short, tortuous, and imperforate ;
and there was a fissure in the perinaeum into
which the urethra (/<) opened.

StellatiJ has recorded an analogous case in
the same animal. The male sexual organs

* LondonMed. and Phys. Journ. vol. ii. (1799),
p. 1, with a good drawing of the malformed organs
of generation.

t Lehrbuch der Pathol. Anat. Bd. ii. s. 195.
pi. ix. fig. 1 & 2, and pi. xxii. fig. 3 & 4.

\ Atti del Real Instit. d'lucoragg. alle Sc. Nat
Naples, torn. iii. p. 380.

3A2

708

HERMAPHRODITISM.

Fig. 300.

a a, the testicles ; b b, epididymes ; c c, vasa defe-
rentia ; d d, vesiculae seminales.

were not entirely complete, and there were
superadded to them a female vagina and an
imperfectly developed uterus, the Fallopian
tubes of which ran towards the inguinal rings,
and terminated with them upon the epididymes
of the testicles.

Another instance of hermaphroditic malfor-
mation in the goat, detailed at great length by
Meckel,* seems also in its principal points
justly referable to the present division of cases,
although there was at the same time a tendency,
in the unequal size of the two cornua uteri,
&c., to a degree of lateral hermaphroditism.

Professor Mayer, of Bonn,f has detailed at
length the dissection of three hermaphroditic

goats, in all of which the conformation of the
sexual parts resembled in its more essential
parts the preceding cases of Thomas and Gurlt.
In all the three instances there were found two
male testicles with their epididymes, vasa de-
ferentia, and vesiculse seminales ; and at the
same time there was present a well-marked
female two-homed uterus, with a vagina open-
ing into the urethra. In the first case the large
hollow cornua uteri terminated in blind ex-
tremities, and there were only very short im-
pervious rudiments of the Fallopian tubes.
In the second case, at the extremity of the
right horn of the uterus, a blind appendicula
was situated, formed by a vestige (according
to Mayer) of the Fallopian tube ; and from
this a ligament was sent off to the correspond-
ing testicle ; a similar ligament, but no appen-
dicula, existed on the left side. In the third
case both Fallopian tubes were present, and
each ended in a bursa formed by the lamina of
the peritonaeum, and partly surrounding the
testicle and epididymes. In two of the in-
stances the ejaculatory ducts seem to have
opened into the urethra near the point at which
the vagina terminated in it ; and in one of the
cases they opened into the canal of the vagina
itself before it joined that of the urethra. All
the external organs were male, but malformed
in so far that the penis was short, and in two
of the cases somewhat twisted; and the scrotum
was either small or wanting.

The same author* has described the dis-
section of a dog, the sexual organs of which
exhibited a similar variety of hermaphroditic
malformation. The Fallopian tubes were per-
vious throughout in this instance, and at their
further extremities opened upon the neigh-
bouring cellular tissue. The body of the two-
horned uterus was very small. On compres-
sing the epididymes and vasa deferentia, a fluid
resembling semen issued from the openings of
the latter into the urethra. The external sexual
parts were those of a hypospadic male.

Several cases of hermaphroditic malforma-
tion in the human subject, similar in their
anatomical characters to the preceding, have
been described by Columbus, Harvey, Petit,
Ackermann, and Mayer.

a. In a person with external hypospadic
male organs, Columbusf found two bodies like
testicles in the situation of the ovaries, and
larger in size than the latter female organs na-
turally are. From each of these testiform
bodies two sets of tubes arose, one of which,
like the male vasa deferentia, passed on to the
root of the penis and opened into the urethra ;
while the other, like the female Fallopian tubes,
were inserted into an uterus. The prostate
gland was absent.

b. Harvey J has mentioned a very small her-
maphroditic embryo, on which he found a
two-horned uterus with two testicles of a very

* R il's Archiv fuer die Physiologic, Bd. xi. * Ib. p. 16. tab. iv. fig. 3, external parts of

s. 334-8. generation ; fig. 4, internal.

t Icones Select. Praeparat. Mus. Anat. Bonn. t De Re Anat. lib. xv.
p. 17-20. tab. iv. fig. 5, and tab. v. figs. 1,2, & 3. $ De Gen. Anim. Exerc. Ixix. p. 304.

HERMAPHRODITISM.

709

small size, and, near the diminutive penis, some
traces of a prostate gland.

c. The observation of M. Petit,* of Namur,
is still more complete. On the body of a sol-
dier, aged twenty-two, who died of his wounds,
and whose external organs appear to have
presented no deviation from the male type
except in the absence of the testicles from the
scrotum, these bodies, with male vasa defe-
rentia, vesiculae seminales, and a prostate, were
found to co-exist with female Fallopian tubes,
and an uterus that was attached to the neck
of the urinary bladder, and opened into the
urethra between this neck and the prostate.
The form of this imperfect uterus, M. Petit
remarks, merited for it rather the name of a
vuuina than of an uterus, and it resembled
more this organ in the female quadruped than
in women. From the body of the uterus, at
three inches from its entrance into the urethra,
two Fallopian tubes arose. These tubes were
perforated, and were three inches and a half
long; their abdominal extremities were not
loose and provided with fimbriae, but were at-
tached to a small soft body on each side,
occupying nearly the natural situation of the
ovaries, but having the substance or structure
of the testicles, and provided with an epidi-
dymis and vas deferens. The vasa deferentia
were each seven inches and a half long, and
were attached to two long and rather slender
vesiculae seminales placed alongside of the
uterus. The vesiculae opened into the urethra
by two ducts.

In a note appended to this case, M. Petit
states that he had been consulted by a man
who rendered blood by the penis regularly
every month, without pain or any troublesome
symptom. Perhaps, adds M. Petit, this man
had also a concealed uterus. \Ve have been
informed, on credible authority, of two similar
cases, the one in a young unmarried man of
seventeen years of age, and the other in a per-
son who had been married for several years
without his wife having had any children.* In
both of these cases the discharge was in very
considerable quantity, and perfectly regular in
its monthly occurrence. Did it consist in a
periodical haemorrhage from the urinary blad-
der or passages only ? or was it as M. Petit
seems to suppose in his instance, of a true
menstrual character, and produced by the re-
productive organs of the female existing inter-
nally, and communicating with the bladder or
urethra ?

d. Professor Ackermann,f of Jena, pub-
lished in 1805 the following interesting case of
the present variety of hermaphroditic malfor-
mation. It occurred in an infant that lived
about six weeks after birth. On dissection,
two testicles were found; one of them had
descended into the scrotum or labium ; the
other had advanced no further than the groin.
Both were perfectly formed, and had their usual
appendages complete. In the natural situa-

* Hist, de 1'Acad. Roy. des Sc. for 1720, p. 38.
^ t lufantis androgym historia ct iconographia,
Ediub. Mod. and Surg. Journ. vol. iii. p. 202.

tion of the female uterus, there was found a
hollow pyriform organ, which, from its locality
and connections, was supposed to be an ute-
rus, though its coats were finer and thinner,
and its cavity greater than naturally belongs to
that viscus. Duplicatures of peritonaeum, re-
sembling theligamenta lata, connected this im-
perfect uterus with the sides of the pelvis, and
its cavity opened into a kind of short vagina,
which soon united with the urethra, and formed
one common canal with it (vagina urethruhs).
The vasa deferentia ran from the testicles
towards the superior angles of the uterus, and
penetrated into its substance at the points
where the Fallopian tubes are usually placed.
Without opening here, however, they passed
onwards under the internal mucous-like mem-
brane of the uterus and vagina, and at length
terminated, by very small orifices, in the va-
gina urethralis. Immediately previous to en-
tering the ligamenta lata, each vas deferens
formed a number of convolutions, conglome-
rated into a mass resembling a vesicula semi-

e. Steghlener* has described at great length
the case of an infant that survived only for
half an hour after birth, and upon whose body
he found perfect external male organs {fig.
301, a 6), and internally two small elon-
gated testicles (c c), with their epididymes (g g\
the convolutions of their vasa deferentia (6 b)

m

9 De Hcrmaphr. Nut. p. 104.

710

I1ERMAP11RODITISM.

distinctly marked. Between the rectum and
bladder there was placed a very large pear-
shaped bag or pouch (./'), with firm, coria-
ceous, but not thick walls, and distended with
fluid. This bag or imperfect cystoid uterus
terminated inferiorly by a narrow neck, in a
vagina that opened into the urethra, in the situ-
ation of the verumontanurn, and was there
dilated into a large bag or ampulla, occupying
exactly the site of the prostate gland, and re-
sembling this organ also in its form and posi-
tion. The internal membrane of the uterus
was collected at its neck into numerous val-
vular-like folds, and that of the vagina had
also a rugous or plicated arrangement. From
the fundus of the large sac of the uterus, and
not from its angles, but from near its middle,
two impervious solid ducts (Fallopian tubes,
or rather vasa deferentia,) arose, and after a
somewhat flexuous course reached the testicle
(c f) lying in the superior part of the iliac
fossae. These ducts had attached to them at one
or two points a number of small reddish nodules
(b b), consisting, according to Steghlener, of
glandular granules, and described by Acker-
mann in his case as vesiculae seminales. The
canal of the urethra was obliterated for a short
distance towards the fossa navicularis, and the
urinary bladder ( j) and uterus (i i) were ex-
tremely distended, and the left kidney (»i) was
vesicular.

Mayer, in the work already referred to,* has
described and delineated the following five
cases of the present species of hermaphroditic
malformation in the human subject, all of
which he had himself met with and dissected.

f. In a foetus of the fourtli month, and
affected with omphalocele and extroversion of the
urinary bladder, he found male testicles (fig- 302,

Fig. 302.

a «) with their epididymes (b b}, and a two-
horned uterus (c) terminating in a vagina (//),
that opened into the posterior part of the uri-
nary bladder (e). From the left testicle a con-
torted vas deferens (/) arose, and ran down to the
vagina; the right vas deferens (g) was shorter,

and became thread-like, and disappeared near
the corresponding cornu of the uterus. A ru-
diment only of the left male vesicula seminalis
was observable. The external organs were
male; the glans penis (h} was imperforate.

g. In another foetus of the sixth month,*
there existed a perfect set of internal and exter-
nal male sexual organs, viz., testicles, epididy-
mes, vasa deferentia, and vesicuUe seminales,
with a prostate gland and a normally formed
penis and scrotum. But besides these, there
was also present an imperfect female uterus,
the body of which divided into two cornua, the
right longer and incurvated, the left shorter and
sacciform. The neck of the uterus was marked
internally by its usual arborescent appearance ;
and it opened into a vagina that terminated in
the urethra near the exit of the latter from the
urinary bladder.

h. In a third casef of hermaphroditic malfor-
mation in an infant who diedof convulsions when
six months old, Mayer found the following blend-
ing of the organs of the two sexes. Of the
internal male genital organs there were present
two bodies at the inguinal rings that were evi-
dently testicles, (Jig. 303, a, «) as was proved

Fig. 303.

* Iconcs Select. &c. p. 8-16. See also Walther
and Graefe's Journal der Chirurgie und Augen-
hcilkunde, Kd. vii. Hft. 3, and Bd. viii. Hft. 2.

not only by their position, but by their form,
coverings, connections, and internal structure,
(" their substance," says Mayer, " being evident-
ly composed of yellow canals") ; their epidi-
dymes (b b} were also distinctly developed, and
each of them sent off a vas deferens (c c), which

* Iconcs, p. 8. tab. ii. fig. 5.

t Icones, p. 9, tab. iii. lig. 1 and 2.

HERMAPHRODITISM.

711

was furnished with a corresponding multilocular
vesicula seminalis (</ d}. Of the internal fe-
male sexual organs there were found a perfectly
developed uterus (e e}, with its broad (n u)
and round (o <>) ligaments naturally formed
and placed, and provided with two Fallopian
tubes (/./') that followed the course of the
testicles through the inguinal canals, and a va-
gina (g) which opened into the urethra (A) near
its external orifice. The ejaculatory ducts of
the male vesiculse seminales opened into this
vagina at / and m. The internal surface of
the vagina was already beginning to present
the appearance of its usual rugae. The cavity
of the uterus was triangular, and exhibited on
the internal part of the cervix its characteristic
plicated or arborescent structure. The Fallo-
pian tubes were, at their uterine orifices, of a
large caliber; their cavity afterwards became
suddenly contracted, and then again dilated,
and terminated at their ulterior extremities,
where they lay in contact with the testicles at
the external inguinal rings, in blind sacs (i t),
without any very distinct appearance of fim-
briae. The external genital parts in this very
interesting case were of a doubtful nature,
being referable either to those of a hypospadic
male, or of a female with a large clitoris, but
without nymphae, the meatus urinarius being in
its normal situation, but leading behind to the
cavities of both the urinary bladder and uterus.
The circle of the pelvic bones was large.

i. The two other instances described by
Mayer occurred in adult subjects, and the mal-
formation in both of them differed from that
found in the cases just now cited in this, that
there was only one testicle present along with
the imperfect uterus.

The subject of one of these cases* was a
person who died at the age of eighteen, and
whose external sexual organs were those of a
hypospadic male, with a narrow perinatal canal
or fissure. On dissection this perinaeal canal
was found to communicate anteriorly with
the urethra, and posteriorly with a vagina of two
inches and nine lines in length, and five or six
lines in caliber. The anterior and posterior
column of rugae belonging to the vagina was
only slightly marked. Its canal led to a
large dilated uterus, the superior part of which
was unfortunately cut away with some dis-
eased viscera before the genital organs were
examined; but, from the portion" left, this
organ seemed to resemble the uterus of quad-
rupeds in its oblong form, and in the thinness
of its walls, which were composed of a caver-
nous fibro-vascular texture, and full of lacunae.
The usual arborescent appearance of the inter-
nal surface of the os uteri was very perfectly
marked. Besides these female organs, there
was a well-formed male prostate gland at the
neck of the bladder ; and behind the abdomi-
nal ring of the right side, a small roundish
body, similar in form and texture to the testi-
cle, and having the cremaster muscle adhering
to* its membranous involucrum. There were
no traces of any similar organ on the left side.

* Jconcs, p. 11. tiib iii. fig. 3 aud 4.

On both sides some portions of a canal were
seen, but whether they were the remains
of the vasa deferentia or Fallopian tubes was
not ascertained on account of the previous
mutilation of the uterus. On each side of the
neck of the uterus there was placed a vesicula
seminalis, provided with an ejaculatory duct
that opened into the orifice of the vagina.
The dimensions of the pelvis approached much
nearer to those of the female than those of the
male. In the secondary sexual characters of
the individual, the female type was further re-
cognised in the want of prominence in the
larynx, in the slender form of the neck, and
(according to Professor Mayer) in the rounded
shape also of the heart, the smallness of the
lungs, the oblong shape of the stomach, the
large size of the liver, the narrowness of the
forehead, and the conformation of the brain ;
while the individual approximated, on the
other hand, to the male in the length and posi-
tion of the inferior extremities, in the breadth
of the thorax, the undeveloped state of the
mammas and the hairy condition of their pa-
pillae, and in the existence of a slender beard
upon the chin and cheeks.

j. In the second adult subject (a person of
eighty years of age) Mayer* found, on the left
side of the cavity of the abdomen, and near
the inguinal ring, a small oval body exhibiting
imperfectly in its internal structure the tubular
texture of the male testicle, and having an
appendix resembling the epididymis attached
to it. From this testicle arose a vas deferens,
which was joined in its course by a vesicula
seminalis, and ended in an ejaculatory duct
On the opposite or right side a vesicula semina-
lis, having no continuous cavity, was present ;
but no vestige of a corresponding testicle, vas
deferens, or ejaculatory duct could be disco-
vered. The prostate gland was present, and
regularly formed. In the cavity of the pelvis
an uterus was found with parietes of moderate
thickness, and of the usual cavernous texture;
its cervix was marked internally with the appear-
ance of the natural arborescent rugae. Inferiorly
it opened into a narrow membranous vagina,
that received the right ejaculatory duct, then
passed through the body of the prostate, and
latterly joined the canal of the urethra. The
fundus of the uterus could not be examined, as
it had been removed in a previous stage of the
dissection. The external parts were male and
naturally formed, with the exception of the
penis, which was shorter than usual, and had
the canal of the urethra fissured inferiorly, and
the meatus urinarius situated at its root. The
individual was during life regarded as a male,
but had all along remained in a state of celi-
bacy. The general appearance of the face and
body was that of an imperfectly marked male,
but the pelvis was broad like that of a female.
3. Co-existence of female ovaries and male
testicles. — This third division of complex or
double hermaphroditism includes all those cases
in which a male testicle and female ovary exist
together either upon one side only, or upon

* Iconcs, p. 15, t:ib. iv. fijt. 1 aud 2.

712

IIERMAPHllODITISM.

both sides of the body. With this arrange-
ment, other malformations by duplicity of the
sexual organs are generally combined ; but
these are so various in their character as not
easily to admit of any useful generalization.
In considering this third division of complex
hermaphroditism, we shall mention, first, the
cases in which two testicles and one, ovary are
stated to have co-existed ; and secondly, those
in which there have been supposed to be pre-
sent two testicles and two ovaries.

Two testicles and one ovary. — The two dis-
sections that we have previously detailed of
lateral hermaphroditic insects, (see Lateral
Hermaphroditism, p. 696,) shew that in these
two cases this variety of sexual duplicity existed.
It appears to have been observed also in two
instances of hermaphroditic malformation in
the quadruped, the histories of which have
been described by Mascagni and Mayer.

In a bull, nine years of age, and which
was provided with the usual external organs of
the male, Mascagni found internally, on dis-
section, a prostrate gland and two perfect
vesiculae seminales, vasa deferentia, epidi-
dymes, and testicles. The testicles and epi-
didymes were injected with mercury through
the vasa deferentia. In addition there was dis-
covered near the left testicle, and connected to
it by peritonaeum and bloodvessels, a body
having the structure of the female ovary ; and,
in its normal situation, there existed a distended
double uterus, containing from fifteen to sixteen
pounds of a clear fluid. This uterus was
furnished with two Fallopian tubes at its upper
part, and terminated mferiorly in a vagina,
which opened by a small orifice into the male
urethra.*

In a goat dissected by Mayer,f he found
two testes with their epididymes fully developed,
and vasa deferentia and vesiculae seminales.
One of the testes was placed without and the
other still remained within the abdominal cavity.
At the same time there were present a large fe-
male vagina communicating with the urethra,
and a double horned uterus provided with two
Fallopian tubes. One of these tubes terminated
in a blind canal, but the other had placed at
its abdominal extremity several vesicles, resem-
bling, according to Mayer, Graafian vesicles,
or an imperfect ovary. The vesiculae seminales
and (through regurgitation by the urethra and
ejaculatory ducts) the cavities of the vagina
and uterus, were filled with about four ounces
of a whitish fluid, having the colour and odour
of male semen. This fluid could not be found
by the microscope to contain any seminal ani-
malcules, but only simple and double Monades
( Monades termones et guttulas). Bergmann,
however, is alleged to have found it, on
analysis, to contain the same chemical principle
that characterizes human male semen.

Two testicles and two ovaries. — Various in-
stances have now been published in which this
sexual duplicity has been supposed to exist

* Atti dell' Acad. dolle Scicnzc di Siena, t. viii.
p. 201.
t Iccmes, p. 20.

among cattle and other domestic quadrupeds,
as well as in the human subject.

One of the free-martins* described by
Mr. Hunter comes under this variety. In the
case referred to, in the situation of the ovaries
" were placed," to use Mr. Hunter's words,
" both the ovaria and testicles," — or, as Sir
Everard Home, in alluding to this case, more
justly expresses it, " an appearance like both
testicles and ovaria was met with close toge-
ther.'^ The two contiguous bodies were nearly
of the same size, being each about a& large as
a small nutmeg. There were no Fallopian
tubes running to the ovaries, but a horn of
an imperfect uterus passed on to them on each
side along the broad ligament. Pervious vasa
deferentia were found ; they did not, however,
reach up completely to the testicle on either
side, or form epididymes. The vesicula; semi-
nales were present, and much smaller than in
the perfect bull. The external parts appear to
have been those of the cow, but smaller than
natural. The vagina passed on, as in the cow,
to the opening of the urethra, and, after having
received it and the orifices of the seminal ducts,
it began to contract into a small canal, which
ran upwards through the uterus to the place of
division of that organ into its two horns.

Velpeau,J in his work on Midwifery, men-
tions that in an embryo calf, he had " found
reunited the testicles and ovaries, the vasa
deferentia, and uterus."

In an hermaphroditic foal-ass, Mr. Hunter§
found both what he considered to be two ovaries
placed in the natural situation of these bodies,
and two testicles lying in the inguinal rings in
a process or theca of peritonaeum similar to
the tunica vaginalis communis in the male ass.
No vasa deferentia or Fallopian tubes could be
detected ; but there was a double-horned
uterus present, and from its broad ligaments,
(to the edges of which the cornua uteri and
ovaries were attached,) there passed down on
either side into the inguinal rings a part similar
to the round ligament in the female. The
horns and fund us of the uterus were pervious ;
but its body and cervix, and the canal of the
vagina from above the opening of the urethra
into it, were imperforate. The external parts
were similar to those of the female ass ; but
the clitoris, which was placed within the
entrance of the vagina, was much larger than
that of a perfectly formed female ; it measured
about five inches. The animal had two
nipples.

Scriba has given an account)) of an herma-
phroditic sheep, in which two large testicles
are stated to have been found in the scrotum,
at the same time that there existed, in their nor-
mal situation, two moderately sized ovaries,
and a small uterus furnished with two appa-
rently closed Fallopian tubes. The external
sexual parts appear to have been those of a

* An. Econ. p. 63-64, pi. ix.
t Comp. Anat. vol. iii. p. 322.
I Truite de 1'Art des Accouchemens, t i. p. 114.
$ An. Kcon. p. 58.

|| Schrifteu dtr Gesellschaft Naturforschcnder
Freude zu Berlin, J3d. x. s. 367.

HERMAPIIRODITISM.

713

malformed male, the penis being short and im-
pervious, the scrotum divided, and the urethra
opening into a contracted perinseal fissure re-
sembling the female vulva. This anjmal had
often attempted connection with the female
sheep.

Borkhausen* has described a very similar
case in the same species of animal. Each half
of the divided scrotum contained a testicle
which was regularly formed, but greater in size
than usual, and furnished with a large sperma-
tic artery. The pelvis contained a normal
uterus, which was smaller, however, than na-
tural ; it was provided with its usual ligaments.
The Fallopian tubes were present but imper-
forate, and the two ovaries were full of vesicles
and inclosed in a strong membrane. The
vagina was natural and opened as in the female.
Behind the divided scrotum the rudiment of
an udder with four teats (instead of two) was
situated. The male penis was also present,
but diminutive and short ; its erectores muscles
were small, and the prostate gland indistinct.
The urethra was single as it left the bladder,
but it afterwards divided into two canals, the
wider of which opened into the female vagina
and vulva, and the narrower ran through the
male penis. The urine passed in a full stream
through the former canal, and only by drops
through the latter. The animal is alleged to
have attempted coition in both ways.

In 1829, an account of an hermaphroditic
goat was published at Naples, which is said to
have been provided with both female ovaries
and male testicles.f The two ovaries occupied
their usual situation ; no Fallopian tubes were
found ; but there were present a double-horned
uterus with blind cornua, and a vagina which
opened externally, as in the female. In the
neighbourhood of the ovaries, and more ex-
ternal than them, two small testicles were dis-
covered, having two vasa deferentia arising
from them. The vasa deferentia ran down-
wards to two corresponding vesicuiae seminales,
that were placed alongside of the uterus. In
the lower angle of the external pudenda, a
body, resembling in length the male penis more
than the female clitoris, was situated : it was,
as we have already had frequently occasion to
mention in regard to the penis in malformed
male quadrupeds, of a very tortuous or con-
voluted form.

We have had an opportunity of examining an
excellent preserved specimen of double herma-
phroditism in the sow, referable to the present
section, which was met with some years ago by
Dr. Knox, and we have his permission to state
here the following particulars of the case.

Among the internal female organs there is
present a natural well-formed double uterus,
provided with broad ligaments and two hollow
cornua, each about six or seven inches in length.
The rimbriated extremities are not distinctly
marked, the female tubes appearing to end

* Rheinisches Mag. zur Erweiterung der Natur-
kunde. Gicsson 1793. Bd. i. *. 608.

t Brcvi cenne su di un Neutro Capro; or,
Guilt's Pathologischen Auatouiie, Bd. ii. s. 198.

blind at their upper terminations, as they have
often been observed to do in similar cases.
The os uteri opens inferiorly into a vagina,
which seems normal in its structure. At a
short distance from the upper extremity of each
horn of the uterus, two bodies of considerable
magnitude are seen lying in close juxta-position.
The smaller of these two bodies is on either
side about the size and shape of a large almond ;
and though internally of an indeterminate
amorphous structure, they are considered by
Dr. Knox as answering to the two ovaries.
The two larger bodies, which are placed
between the supposed ovaries and the upper
extremities of the cornua uteri, are most dis-
tinctly testicles, as shewn by their numerous tor-
tuous seminiferous tubes, which have been suc-
cessfully filled with-a mercurial injection. They
are of the full size of the organ in the adult
male. The seminiferous tubes of each testicle
terminate in a vas deferens, which was injected
from them ; and the two vasa deferentia run
downwards through the ligamenta lata of the
uterus, and terminate inferiorly in the upper
part of the vagina, thus following the course
of those natural canals in the female sow that
we shall afterwards have occasion to allude to
at greater length under the name of Gaertner's
ducts, and which Dr Knox, from the evidence
of the present case, believes to be in reality
typical of the male vasa deferentia. There is
no trace of vesicuiae seminales. Externally
the vagina opened along with the urethra upon
the perinaeum, at a point lower than natural in
the well-formed female. The clitoris in situa-
tion and size was nearly normal.

The animal at the time of death was fourteen
months old ; it was ferocious in its habits ; and
it had been in vain tried to be fattened. It had
repeatedly shewn strong male propensities, and
at the season of heat its vagina is said to have
presented the usual injected appearance ob-
served in the female sow.

Dr. Harlan of Philadelphia* has lately
described a still more perfect instance of dou-
ble hermaphroditism than any of the preceding,
which he met with in the body of a gibbon or
orang outang, from the Island of Borneo
/'Simla concolor). This animal died of tuber-
cular disease in Philadelphia in 1826, when it
was considered to be under two years of age.
Dr. Harlan gives the following account of its
sexual formation. The penis (^/zg.304, a) was
about one inch in length, and subject to erec-
tions ; it terminated in an imperforate glans ;
and a deep groove on its inferior surface served
as a rudimentary urethra. This groove extended
about two-thirds of the length of the penis,
the remaining portion being covered with a thin
articular diaphanous membrane, which extended
also across the vulva (6), and closed the external
orifice of the vagina. The vagina was rather
large, and displayed transverse striae. Traces
of the nymphae and labia externa were visible.
The meatus urinarius opened beneath the pubis
into the vagina, but the urine must have been
directed along the groove of the penis by the

* Med. and Phys. Researches, p. 19.

714

IIERMAPHRODITISM.

Fig. 304.

External sexual organs and testicles.

gg, the prepuce ; hh, the vasa deferentia j i, the
anus ; AA, ischiatic protuberances.

membrane obstructing the orifice of the vulva.
The os tinea was surrounded by small globular
glands. The orifice and neck of the uterus
admitted a large probe into the cavity of that
organ, which appeared perfect with all its ap-
pendages. The round and broad ligaments,
together with well-developed ovaries (jig. 305,
b 6), were all found in situ. The scrotum

Fig. 305.

Internal sexual organs seen from behind.

d, the urinary bladder -, ff, rectum j gg, broad
ligaments j cc, Fallopian tubes.

(fig- 304, c) was divided, and consisted of a
sac on each side of the labia externa, at the
base of the penis, covered with hair. The
testicles (Jig. 304, d d) lay beneath the skin of
the groin about two inches from the symphysis
pubis, obliquely outwards and upwards : they
appeared to be perfectly formed with the epi-
didymis (J'f}, &c. The most accurate examina-
tion could not discover vesiculse seminales ; but
an opening into the vagina, above the meatus
urinarius, appeared to be the orifice of the vas
deferens. In all other respects the male and
female organs of generation were in this animal
as completely perfected as could have been
anticipated in so young an individual, and
resembled those of other individuals of a
similar age.

Two imperfect instances are on record of the
co-existence of male testicles^and female ovaries
in the human subject.

a. The first of these cases is detailed by
Schrell.* It occurred in an infant who died
when nine months old. All the internal and
external male organs were present and perfectly
formed, with the exception of the prepuce of the
penis, which seemed divided in front and rolled
up. At the root of the large penis, was a small
vulva or aperture capable of admitting a pea,
and provided with bodies having an appearance
of labia and nymphae. This vulva led into a
vagina that penetrated through the symphysis
pubis, and terminated in a nipple-like body or
imperfect uterus, to which, structures having a
resemblance to the Fallopian tubes and ovaries
were attached.

b. The other and still more doubtful case of
the alleged existence of both testicles and
ovaries in the human subject, was first pub-
lished by Beclard.f The case was met with
by M. Laumonier of Rouen, who injected and
dissected the sexual parts, and deposited them
in a dried state, along with a wax model repre-
senting them in their more recent condition, in
the Museum of the School of Medicine at
Paris. In the wax model two female ovaries
with an uterus, vagina, external vulva, and
large imperforate clitoris, are seen combined
with two male testicles, the vasa deferentia of
which terminate in the uterus at the place at
which the round ligaments are normally situ-
ated ; these ligaments themselves are wanting.
The preparation of the dried sexual parts is far
from being equally satisfactory, and, in its
present imperfect condition at least, does not
bear out by any means the complete double her-
maphroditic structure delineated in the model.

III. HERMAPHRODITISM AS MANIFESTED IN
THE GENERAL CONFORMATION OF THE BODY,
AND IN THE SECONDARY SEXUAL CHARAC-
TERS.

In the preceding observations we have prin-
cipally confined ourselves to the description of
hermaphroditic malformations as seen in the
resemblance in appearance and structure of the

* Schenk's Medic. Chirurg. Archiv. Bd. i. s.
t Bullet, de la Fac. do Med. 1815, p. 284 ; or,
Diet, des Sc. Med. xxi. p. 111.

HERMAPHRODITISM.

715

external genital parts of one sex to those of the
other, and in the different degrees and varieties
of reunion or co existence of the reproductive
organs of the two sexes upon the body of the
same individual. Hermaphroditism, however,
may appear not only in what are termed the
primary sexual parts or characters, or, in other
words, in the organs more immediately subser-
vient to copulation and reproduction, but it
may present itself also in the secondary sexual
characters, or in those distinctive peculiarities
of the sexes that ave found in other individual
parts and functions of the economy, as well as
in the system at large. We have occasionally
an opportunity of observing some tendency to
an hermaphroditic type in the general system,
without there being any very marked corre-
sponding anormality in the sexual organs them-
selves, but it rarely happens that there exists
any hermaphroditic malformation of the primary
organs of generation, without there being con-
nected with it more or less of an hermaphrodi-
tic type in the secondary sexual characters ;
and this circumstance often offers us, in indivi-
dual doubtful cases, a new and perplexing
source of fallacy in our attempts to determine
the true or predominating sex of the malformed
individual. Before, however, describing that
variety of hermaphroditism which manifests
itself in the general system and in the secon-
dary sexual peculiarities, it will be necessary,
in order to understand its nature and origin, to
premise a few remarks on the dependence and
relation of these secondary characters upon the
normal and abnormal conditions of the primary
sexual organs.

That the various secondary sexual peculiari-
ties which become developed at the term of
puberty are intimately dependent upon the
changes that take place at the same period in
the organism of the female ovaries and male
testicles, seems proved by various considera-
tions, particularly by the effect produced by
original defective development and acquired
disease in these parts, and by the total removal
of them from the body by operation. In consi-
dering this point we shall speak first of the
effects of the states of the ovaries upon the
female constitution, and shall then consider
those of the testicles upen the male.

When the usual development of the ovaries at
the term of puberty does not take place, the se-
condary sexual characters which are naturally
evolved in the female at that period do not pre-
sent themselves ; and this deficiency sometimes
occasions an approach in various points to the
male formation. Thus in a case recorded by
Dr. Pears,* of a female who died of a pectoral
affection at the age of twenty-nine, the ovaries
on dissection were found rudimentary and in-
distinct, and the uterus and Fallopian tubes
were present, but as little developed as before
puberty. This individual had never menstru-
ated nor shewed any signs, either mental or
corporeal, of puberty. The mammae and nip-
ples were as little developed as those of the
male subject. She had ceased to grow at ten

* Phil. Trans, for 1805, p. 225.

years of age, and attained only the height of
four feet six inches.

In another analogous instance observed by
Renauldin,* scarcely any rudiments of the
ovaries existed, and the body of the uterus was
absent, but the external genital female organs
were well formed. The individual who was
the subject of this defective sexual development
had never menstruated ; the mammae were not
evolved ; in stature she did not exceed three
and a half French feet ; and her intellect was
imperfectly developed.

In reference to these and other similar in-
stances that might be quoted,f it may be ar-
gued that they do not afford any direct evidence
of the evolution of the sexual characters of the
female depending upon that of the ovaries, as
the arrestment in the development of both may
be owing to some common cause which gives
rise at the same time to the deficiency in the
development of the genital organs, and to the
stoppage of the evolution of the body in gene-
ral. That the imperfection, however, in the
organism of the ovaries may have acted in such
cases as the more immediate cause or precedent
of the imperfection or non-appearance of the
secondary characters of the sex, seems to be
rendered not improbable, in regard to some, if
not to all the instances alluded to, by the fact
that the removal of these organs before the
period of puberty, as is seen in spayed female
animals, entails, upon the individuals so treated,
the same neutral state of the general organiza-
tion as was observed in the above instances ;
or, in other words, we have direct evidence that
the alleged effect is capable of being produced
by the alleged cause ; and further, when in
cases of operation or disease after the period of
puberty, both ovaries have happened to be de-
stroyed, and their influence upon the system
consequently lost, the distinctive secondary
characteristics of the female have been observed
also to disappear in a greater or less degree.

Thus in the well-known case recorded by
Mr. Pott,J the catamenia became suppressed,
the mammae disappeared, and the body be-
came thinner and more masculine, in a healthy
and stout young woman of twenty-three years
of age, whose two ovaries formed hernial tu-
mours at the inguinal rings, and were, in con-
sequence of their incapacitating the patient
from work, both removed by operation.

Many facts seem to show that the act of
menstruation most probably depends upon
some periodical changes in the ovaries, if not,
as Dr. Lee§ supposes, in the Graafian vesicles
of these organs; and when the function be-
comes suddenly and permanently stopped in a

* Seances de 1'Acad. Roy. de Med. 28 Fevrier
1826, and Medical Repository for 182b', p. 78.

t Davis, in his Principles and Practice of Obste-
tric Medicine, p. 513, refers to several instances in
point. We may mention that Dr. Haighton found
that after the Fallopian tubes were divided in rab-
bits, the ovaries became gradually atrophied, and
the sexual feelings were lost. Phil. Trans, for
1797, p. 173.

| Surgical Works, vol. iii. p. 329.

$ Article OVARY in Cyclo. of Pract. Med.

716

IJERMAPHRODITISM.

woman at the middle period of life, without
any indications of the catamenial fluid being
merely mechanically retained, we may perhaps
suspect with reasonable probability the exist-
ence of a diseased state which has destroyed
eithei successively or simultaneously the func-
tions of both ovaries. In such a case the dis-
tinctive secondary peculiarities of the female
sex come to give place to those of the male.
Thus Vaulevier mentions an instance in which
menstruation suddenly ceased in a young and
apparently healthy woman ; no general or local
disease followed ; but soon afterwards a perfect
beard began to grow upon her face.* Again,
in women who have passed the period of their
menstrual and child-bearing life, and in whom
consequently the functions and often the healthy
structure of the ovaries are lost or destroyed, we
have frequently an opportunity of observing a
similar tendency towards an assumption of
some of the peculiarities of the male ; an in-
crease of hair often appears upon the face, the
mammae diminish in size, the voice becomes
stronger and deeper toned, the elegance of the
female form and contour of body is lost, and
frequently the mind exhibits a more determined
and masculine cast. Women, both young
and aged, with this tendency to the male cha-
racter, are repeatedly alluded to by the Roman
authors under the name of viragines ; and Hip-
pocrates f has left us the description of two
well-marked instances.

Among the females of the lower animals a
similar approach to the male character in the
general system not unfrequently shows itself
as an effect both of disease and malformation
of the sexual organs, and also in consequence
of the cessation of the powers of reproduction
in the course of advanced age. Female deer
are sometimes observed to become provided at
puberty with the horns of the stag,j and such

* Journ. deMed. torn. Ixix. and Meckel in Reil's
Arch. Bd. xi. s. 275. Meckel quotes other similar
cases from Seger in Ephem. Nat. Cur. Dec. i.
Ann. ix. and x. obs. 95; Vicat, sur la Plique
Polonaise, in Murray's Pr. Bibl. Bd. i. s. 578 ;
and Schurig's Parthenologia, p. 184. Burlin pub-
lished an express treatise on the subject, De barba
mulierum ex menstruorum suppressione, Altorf.
1664. See also Haller's Elera. Phys. torn. v. p.
32 ; Reuss, Repert. Comment, torn. x. p. 205 ;
Eble, Die Lehre von den Haaren in der organischen
Natur. Bd. ii. s. 222. Vien. 1831 ; and Mehliss,
Ueber Virilescenz und Rejuvenescenz thierischer
Korper. Leipz. 1838, who quotes several cases
additional to those of Meckel.

* De Morb. Vulg. lib. vi. ss. 55,56. '< Abderus
Phaetusa, Pythei conjunx, antea per juventam
foecunda erat ; viro autem ejus exortante, din ar-
ticulos exorti sunt. Quas ubi contigerunt, turn cor-
pus virile, turn in universum hirsutum est reddi-
tum, barbaque est enata, et vox aspera reddita.
Sed cum omnia quae ad inensss deducendos facerent
tentassemus. non profluxerunt, verum hand ita
multo post vita functa est. Idem quoque in Thaso
Namysiae, Gorgippi conjugi, contigit." Hippocr.
Op. ed. Foesii, p. 1201.

t Camden's Angl. Norm. (1603) p. 821. Lan-
gelot Eph. Nat. Cur. Dec. i. ann. ix and x. obs.
88. Ridinger's Abbild. Seltener Thiere Tat'. 79, or
Meckel in Reil's Archiv. filr die Physiol. Bd. xi.
p. 273.

animals are generally observed to be barren,*
probably in consequence either of a congenital
or acquired morbid condition of their ovaries
or other reproductive organs. In old age, also,
after the term of their reproductive life has
ceased, female deer sometimes acquire the
horns of the male in a more or less perfect de-
gree;! and Burdach alleges that roes sometimes
become provided with short horns when they
are kept from the male during the rutting sea-
son, and at the same time furnished with abun-
dant nourishment.! Mehliss § alludes to two
cases in which a virilescent type was shewn
principally in the hair of the female deer. In
one of these instances the hair of the head,
neck, and abdomen, the shape of the ears and
extremities, and the odour of the animal, gave
it the closest resemblance to the male, and it
followed the other females as if urged by sexual
desire.

This kind of acquired hermaphroditism in
aged females has, however, been moie fre-
quently and carefully attended to as it occurs
in Birds than as met with among the Mamma-
lia, the change to virilescence in the former
being more marked and striking than in the
latter, owing to the great difference which gene-
rally exists between the plumage of the male
and female. || When old female birds live for
any considerable period after their ovaries have
ceased to produce eggs, they are usually ob-
served to assume gradually more or less of the
plumage and voice, and sometimes the habits
also of the male of their own species. This
curious fact, first pointed out by Aristotle If in
relation to the domestic fowl, has now been
seen to occur in a number of other species of
birds, but particularly among the Gallinaceae.
It has been in modern times remarked in the
common fowl ( Phasianus gallus) by Tucker,
Butler, and Jameson; in the common pheasant
(P. colchicus) by Hunter and Isidore St.
Hilaire; in the golden pheasant (P.plctus)
by Blumenbach and St. Hilaire ; in the silver
pheasant (P. nychemerus) by Bechstein and
St. Hilaire ; in the turkey ( Meleagris) by
Bechstein ; in the pea-hen (Pavo) by Hunter
and Jameson ; and in the partridge ( Tetrao
penlrix) by Montagu and Yarrell. Among
the Cursores it is mentioned as having occurred
in the bustard (Otis) by Tiedemann, and in
the American pelican (Platalea aiaia) by
Catesby. In the order Palmipedae it has been
observed by Tiedemann and Rumball in the

* Wildungen, Taschenbuch fur Forst- und Jagd-
freunde, s. J7.

t Otto's Path. Anat. by South, p. 166, s. 123,
n. 18, for list of cases.

t Phys. vol. i. § 183, p. 318.

§ Ueber Virilescenz Thierisch. Koerper ; or
British and Foreign Med. Review, vol. vi. p. 77.

|| It occurs also more frequently among birds
than among mammalia, from the former possessing
only a single ovary.

1l " Gallini, cum vicerint gallos, concurrunt ma-
rcsque imitandi subagitare conantur. Attollitur
etiam crista ipsis, simul et clunes (uropygium) ;
adeo ut jam non facile diagnoscantur an fceminaj
sint. Quibusdam ctiam calcaria parva surriguu-
tur." Hist. Animal, lib. ix. cap. 36.

IIERMAPHRODITISM.

717

domestic and wild duck (Anas boscha).
Among the Scansores it has been seen in the
cuckoo (Cuculus cunorns) by Payraudeau ;
and among the Passeres in the cotinga ( Am-
pelia) by Dufresne ; in the chaffinch ( Frin-
giUa)saad rougequcue ( Motacilla) by Prevost ;
and in the bunting ( Emberiza paradistea and
longicauda) by Bluraenbach.

This change of plumage in old female birds
commences, accord ing to M.Isidore St. Hilaire,*
much sooner in some instances than in others ;
it may only begin to show itself several years
after the bird has ceased to lay, though depend-
ing more or less directly upon this phenomenon,
and sometimes it commences immediately after
it. The change may be effected in a single
season, though in general it is not complete for
some years. \Vhen it is perfected, the female
may display not only the variety of colours, but
also the brilliancy of the male plumage, which
it sometimes resembles even in its ornamental
appendages, as in the acquisition of spurs, and,
in the domestic fowls, of the comb and wattles
of the cock. The voice of the bird is also very
generally changed. Its female habits and in-
stinct are likewise often lost ; and, in some in-
stances, it has been seen to assume in a great
degree those of the male, and has even been
observed to attempt coition with other females
of its own species f In most of the female
birds that have undergone this change, the
ovary has been found entirely or partially dege-
nerated, though in a few cases the morbid alte-
ration is not very marked, eggs having even
been present in the organ in one or two in-
stances. In general, however, it is greatly
diminished in size, or has become altogether
atrophied ; but the perfection of the change in
the plumage does not seem to bear any direct
ratio with the degree of morbid alteration and
atrophy in the ovary.

That the changes towards the male type, de-
scribed as occasionally occurring in old female
birds, is directly dependent, not upon their age,
but upon the state of the ovaries in them,
seems still further proved by similar changes
being sometimes observed in these females long
previous to the natural cessation of the powers
of reproduction, in consequence of their ovaries
having become wasted or destroyed by disease.
Greve,J in his Fragments of Comparative
Anatomy and Physiology, states that hens
whose ovaries are scirrhous crow sometimes
like cocks, acquire tail-feathers resembling

* Edinburgh Journ. of Philosoph. Science, (1826)
p. 308.

t Rumball, in Home's Comparative Anatomy,
vol. iii. p. 330, states having observed an old duck
which had assumed the male plumage, attempt
sexual connection with another female. This may
perhaps enable us to understand the reputed cases
of hermaphroditism in women, who, as related by
Mollerus (Tract, de Hermaphr. cap. ii.) and Blan-
card, (Collect. Medico- Phys. cent. iii. obs. 80,)
after having themselves borne children became ad-
dicted to intercourse with other females. Of course
we cannot give our credence to the alleged success-
ful issue of such intercourse.

J Bruchstuecke sur vergleich. Auat. und Phvsiol.
8.45.

those of the male, and become furnished with
large spurs. The same author mentions also
the case of a duck, which, from being previously
healthy, suddenly acquired the voice of the
male, and on dissection its ovary was found
hard, cartilaginous, and in part ossified.

Mr. Yarrell, in a paper read before the Royal
Society in 1827,* has stated that in a number
of instances he had observed young female
pheasants with plumage more or less resem-
bling the male, and in all of them he found on
dissection the ovaries in a very morbid state,
and the oviduct diseased throughout its whole
length, with its canal obliterated at its upper
part. He also shews that a similar effect upon
the secondary sexual characters of the female
bird is produced by the artificial division and
removal of a small portion of their oviduct in
the operation of making capons of female poul-
try ; and he states that his investigations have
led him to believe that in all animals bearing
external characters indicative of the sex, these
characters will undergo a change and exhibit
an appearance intermediate between the perfect
male and female, wherever the system is de-
prived of the influence of the true sexual organs,
whether from original malformation, acquired
disease, or artificial obliteration.f

From the frequency with which castration is
performed, the effects of the testicles in evol-
ving the general sexual peculiarities of the male
have been more accurately ascertained than
those of the ovaries upon the female consti-
tution. These effects vary according to the age
at which the removal of the testicles takes
place. When an animal is castrated some time
before it has reached the term of puberty, the
distinctive characters of the male are in general
never developed ; and the total absence of these
characters, together with the softness and re-
laxation of their tissues, the contour of their
form, the tone of their voice, and their want
of masculine energy and vigour, assimilate
them more in appearance and habits to the
female than to the male type. If the testicles
are removed nearer the period of puberty, or
at any time after that term has occurred, and

* Phil. Trans, for 1827, partii. p. 268.

t On old or diseased female birds assuming the
plumage, &c. of the male, see J. Hunter, Observ.
on the An. Econ. p. 75; E. Home, Lect. on Comp.
Anat. vol. iii. p. 329; Mauduit, in Encycl. Method.
Art. Faisan, torn. 'ii. p. 3 ; Butter, in Wernerian
Soc. Mem. vol. iii. p. 183 ; Schneider's Notes, in
his edition of the Emperor Frederick the Second's
Treatise " De Arte Venandi cum Avibus;" Tucker's
Ornithologia Damnoniensis ; Catesby's Natural
History of Carolina, &c. i. t. 1. ; Bechstein,
Naturgeschichte d. Deutschlands, bd. ii. § 116;
Blumenbach, De anomalis et vitiosis quibusdam
nisus formativi aberrationibus, p. 8 ; and Instil, of
Physiology, p. 369 ; Payrandeau, Bull, des Sc.
Nat. t. xiii. pj 243 ; Tiedemann, Zoologie, vol.
iii. p. 306 ; Geoff. St. Hilaire, Phil. Anat. torn. ii.
p. 360 ; Isid. St. Hilaire, Mem. du Mus. d'Hist. Nat.
torn. xii. p. 220 ; Annal. des Sc. Nat. t. vii. p. 336,
or Edinburgh New Philosophical Journal for 1826,
p. 302, with additional cases by Professor Jameson,
p. 309 ; Kob, De mutatione sexus, p. 11. Berlin
1823 ; Yarrell, Phil. Trans, for 1827, p. 268, with
a drawing of the diseased ovaries, &c.

718

HERMAPHRODITISM.

when the various male sexual peculiarities have
been already developed, the effect is seldom
so striking; the sexual instincts of the animal,
and the energy of character which these in-
stincts impart, are certainly more or less com-
pletely destroyed, and the tone of the voice is
sometimes changed to that of puberty; but the
general male characteristics of form, such as
the beard in man, and the horns in the Ru-
minantia, most commonly continue to grow.
In animals, such as the stag, which possess
deciduous horns, the removal of the testicles
during the rutting season causes the existing
horns to be permanent ; and if the operation is
performed in an adult animal when out of heat,
no new horns in general appear.* In the ox,
the effect of castration upon the growth of the
horns, even when performed before the time
of puberty, is quite remarkable ; for instead of
having their development altogether stopped,
or their size at least diminished by the opera-
tion, as occurs in the ram and stag, the volume
of these appendages is even increased by the
operation, the horns of the ox being generally
larger but less strong than those of the entire
bull. Castration in the boar causes, according
to Greve,f the tusks to remain small, and pre°
vents altogether the replacement of the teeth.
This author also states that the same operation
on the horse prevents the full development of
the neck, renders the teeth smaller and slower
in their growth, increases the growth of the
hair, and the size of the horny protuberances
on the inside of the legs. The prostate gland,
he further alleges, as well as the vesiculae se-
minales, become augmented as much as a
third in their volume in consequence of the
operation .J

The removal of the testicles both before and
after the period of puberty commonly gives
rise to another singular effect, — to an increased
deposition of fat over the body, as has already
been mentioned in the article ADIPOSE TISSUE,
and from this circumstance the general form
of the body, and in man that of the mammae,
is sometimes modified in a degree that in-
creases the resemblance to the opposite sex.
In the sterile of both sexes in the human sub-
ject an unusual corpulency is not uncom-
mon, and the same state is often met with in
old persons, and particularly in females, after
the period of their child-bearing life is past.

The nature of the effects produced by the
existence and functional activity of the testicles
and ovaries upon the development of the se-
condary sexual characters of the male and
female, may be further illustrated by what
occurs in the season of heat to animals such
as the deer, sheep, birds, &c. that have peri-
odical returns of the sexual propensity. At these
periods all the distinctive general characters
of the sexes become much more prominently
developed, in conjunction with, and apparently
in consequence of, the changes which have

* Buffon, Hist. Nat. torn. vi. p. 80.

t Bruchstuecke zur Vergl. Anat. und Physiol.
p. 41.

* Loc. cit. p.. 45.

been ascertained by observation to occur at that
time in the relative size and activity of the in-
ternal organs of generation. Thus with the
return of the season of sexual instinct the
dorsal crests and cutaneous ear-lobes of tritons
enlarge; in Batrachian Reptiles the spongy
inflations of the thumbs become increased in
size; the various species of singing birds re-
acquire their vocal powers ; and some, as the
cuckoo and quail, appear capable of exercising
their voice only at this period of the year.
At the pairing season also the plumage of birds
becomes brighter in tint, and in some instances
is in other respects considerably changed, as
in the male ruff ( Trlnga pugnax), who then
reassumes the tuft of feathers upon his head
and neck, and the red tubercles upon his face
that had fallen off during the moulting, and
thus left him more nearly allied in appearance
to the female during the winter. In reference
to this subject, it appears to us interesting to
remark, that in certain birds, as in the different
species of the genus Fringilla, the male pre-
sents in winter a plumage very similar to that
of the female,* and in the present inquiry it is
important to connect this fact with the very
diminutive size and inactive condition of the
testicles of these birds at that season. (See
AVES.)

From the remarks that we have now made
upon the influence of the ovaries and testicles
in developing the general sexual peculiarities
of the female and male, it will be easy to con-
ceive that when, in cases of malformation of
the external genital organs giving rise to the
idea of hermaphroditism, there is at the same
time, as sometimes happens, a simultaneous
want of development in the internal organs of
reproduction, particularly in the ovaries and
testicles, the general physical and moral pecu-
liarities distinctive of the sex of the individual
may be equally deficient, or have a tendency
even to approach in more or fewer of their
points to those of the opposite sexual type.
In this way we may, it is obvious, have general
or constitutional hermaphroditic characters, if
they may be so termed, added to those al-
ready existing in the special organs of gene-
ration, and rendering more difficult and com-
plicated the determination of the true sex of
the malformed individual. Some cases of spu-
rious hermaphroditism in the male published
by Sir E. Homef may serve to illustrate this
remark.

A marine soldier, aged twenty-three, was
admitted a patient into the Royal Naval Hos-
pital at Plymouth. He had been there only a
few days, when a suspicion arose of his being
a woman, which induced Sir Everard to ex-
amine into the circumstances. He proved to
have no beard; his breasts were fully as large
as those of a woman at that age ; he was in-
clined to be corpulent; his skin was uncom-
monly soft for a man ; his hands were fat and
short, and his thighs and legs very much like
those of a woman : the quantity of fat upon

* Stark's Elements of Nat. Hist, vol.i. p. 243.
t Comp. Anat. vol. iii. p. 320.

HERMAPHRODITISM.

719

the os pubis resembled the mons veneris ; and
in addition he was weak in his intellect, and
deficient in bodily strength. The external
genital organs shewed him to be a male, but
the penis was unusually small, as well as short,
and not liable to erections ; the testicles were
not larger in size than they commonly are in
the foetal state ; and he had never felt any pas-
sion for the opposite sex.

The following cases by the same author
strongly illustrate this subject.* In a family of
three children residing near Modbury in De-
vonshire, the second, a daughter, was a well-
formed female, the eldest and youngest were
both malformed males. The eldest was thir-
teen years of age. His mons veneris was
loaded with fat ; no penis could be said to be
present, but there was a praeputium a sixth of
an inch long, and under it the meatus urina-
rius, but no vagina. There was an imperfect
scrotum with a smooth surface, there being no
raphe in the middle, but, in its place, an in-
dented line ; it contained two testicles, of the
size that they are met with in the foetus. His
breasts were as large as those of a fat woman.
He was four feet high, and of an uncommon
bulk, his body round the waist being equal to
that of a fat man, and his thighs and legs in
proportion. He was very dull and heavy, and
almost an idiot, but could walk and talk ; he
began to walk when a year and a half old.
The younger brother was six years old, and
uncommonly fat and large for his age. He
was more an idiot than the other, not having
sense enough to learn to walk although his
limbs were not defective.

A case in a similar manner confirmatory
of the preceding remarks is mentioned by Itard
de Riez.f A young man, aged twenty-three,
had no testes in the scrotum, a very small penis,
not capable of erection, and a divided scrotum.
He was in stature below the middle size. His
skin was soft, smooth, and entirely free from
hair, the place of the beard being supplied by
a slight down. The voice was hoarse; the
muscles were not, well marked ; the form of the
chest resembled that of the female, and the
pelvis was extremely broad and large. The
intellectual faculties were very dull, and the
sexual appetite was entirely wanting.

Renauldin, also, in the same work,]: has re-
corded another case in point. In a soldier of
twenty-four years of age, whose genital organs
were extremely undeveloped, his penis being
only of the size of a small tubercle, and his
testicles not larger than small nuts, the pelvis
was broad; the chest narrow; the face and
body in general were not covered with hair,
with the exception of a small quantity upon
the pubis ; the voice was feminine, and the
mammary glands were as perfectly developed
as in the adult female. The body of this in-
dividual was rather lean than otherwise. The

• Ib. p. 320-21.

t Memoires de la Societ6 Med. d'Emulation
torn. iii. p. 293-5.
$ Tom. i. p. 241.

mammae had begun to enlarge when his body
attained to its full stature at sixteen years of
age. He had all the habits and sexual desires
of the male sex.

In quadrupeds as in man, when the tes-
ticles or ovaries are imperfectly formed, the
secondary sexual peculiarities are frequently
so defectively evolved as to offer a kind of her-
maphroditic or neutral type in the general con-
figuration and characters of the animal. Thus,
the free-martin does not present an exact
analogy in form either with the bull or cow,
but exhibits a set of characters intermediate
between both, and more nearly resembling
those of the ox and of the spayed heifer. In
size it resembles the castrated male and spayed
female, being considerably larger than either
the bull or the cow, and having horns very
similar to those of the ox. Its bellow is simi-
lar to that of the ox, being more analogous
to that of the cow than of the bull. Its flesh,
like that of the ox and spayed heifer, is gene-
rally much finer in its fibre than the flesh of
either the bull or cow, and is supposed to
exceed even that of the ox and heifer in deli-
cacy of flavour.*

The consideration of the various facts that
we have now stated inclines us to believe that
the natural history characters of any species
of animal are certainly not to be sought for
solely either in the system of the male or ir>
that of the female ; but, as Mr. Hunter pointed
out, they are to be found in those properties
that are common to both sexes, and which we
have occasionally seen combined together by
nature upon the bodies of an unnatural her-
maphrodite; or evolved from the interference
of art, upon a castrated male or spayed female.
In assuming at the age of puberty the distinc-
tive secondary peculiarities of his sex, the
male, as far as regards these secondary pecu-
liarities, evidently passes into a higher degree
of development than the female, and leaves
her more in possession of those characters that
are common to the young of both sexes, and
which he himself never loses, when his tes-
ticles are early removed. These and other
facts connected with the evolution of both the
primary and secondary peculiarities of the
sexes further appear to us to shew that, phy-
siologically at least, we ought to consider the
male type of organization to be the more per-
fect as respects the individual, and the female
the more perfect as respects the species.
Hence we find that, when females are mal-
formed in the sexual parts so as to resemble
the male, the malformation is almost always
one of excessive development, as enlargement
of the clitoris, union of the labia, &c. ; and,
on the other hand, when the male organs are
malformed in such a manner as to simulate the
female, the abnormal appearance is generally
capable of being traced to a defect of deve-
lopment, such as the want of closure of the
perinaeal fissure, and of the inferior part of the
urethra, diminutive size of the penis, retention

* Hunter's Obs. on the An. Econ. p. 60.

720

IIERMAPilRODITISM.

of the testicles in the abdomen, &c. In the
same way, when the fema'e assumes the secon-
dary characters of the male, it is either, fiist,
when by original malformation its own ovaries
and sexual organs are so defective in structure
as not to be capable of taking a part in the
function of reproduction, and of exercising
that influence over the general organization
which this faculty imparts to them; or,
secondly, when in the course of age the ovaries
have ceased to be capable of performing the
action allotted to them in the reproductive
process. In both of these cases we observe
the powers of the female organization, now
that its capabilities of performing its particular
office in the continuation of the species are
wanting or lost, expend themselves in perfecting
its own individual system, and hence the ani-
mal gradually assumes more or fewer of those
secondary sexual characters that belong to the
male.

We do not consider it subversive of the pre-
ceding view to qualify it with the two follow-
ing admissions, — 1st, that, owing to the ener-
gies of the female system being so strongly
and constantly directed towards the reproduc-
tive organs, and the accomplishment of those
important functions which these organs have to
perform in the economy of the species, the
general characters of the species may be de-
veloped in her body in a degree less than they
otherwise would be, or than actually consti-
tutes the proper standard of the species ; and,
2dly, in consequence of the peculiarities of
the sexual functions of the female, some of
the individual organs of her system, as the
mammae, are evolved in a degree greater than
is consonant with the standard characters of the
species. At the same time we would here
remark that the occasional enlarged condition
of the mammae in hermaphrodites in whom the
male sexual type of structure predominates,
(as in the examples of spurious male herma-

fhrodites that have been quoted from Sir E.
lome, and in other instances mentioned by
Renauldin, Julien, Petit, Rullier, and others
in the human subject, as well as in numerous
cases among hermaphrodite quadrupeds,) would
almost seem to shew that the full development
of the mammary glands is a character proper
to the species in general, rather than one pecu-
liar to the female system alone. In males,
also, who are perfect in their reproductive
organs and functions, the mammae are some-
times observed to be developed in so complete
a manner as to be capable of secreting milk,
forming what may be regarded as one of the
slightest approaches towards hermaphroditic
malformation in the male organization;* and

* The secretion of milk in the mammary glands
of the male is occasionally observed amongst our
domestic quadrupeds. See Gurlt's Pathologischen
Anatomic der Haus-Saugthiere, Bd. ii. s. 188 ;
Blumenbach in the Hanoversich Magazin for 1787 ;
and Home in Comp. Anat. iii. p. 328. Among
the recorded instances and observations upon it in
man we may refer to Paullini, Cynographia, p. 52 ;
Schacher, De Lacte Virorum et Virginum, Leipz.

the mammae of the infants of both sexes not
unfrequently contain a hictiform fluid at birth.

In some instances of hermaphroditic mal-
formation the total form and configuration of
the body have been alleged to present not only
a general tendency towards the physical se-
condary characters of the opposite sex, or to
exhibit in a permanent stale the neutral con-
dition existing before puberty, but different
individual parts of it have been occasionally
conceived to be developed after a different
sexual type. Thus, for instance, we have al-
ready mentioned in regard to Hubert Jean
Pierre, that the upper half of the body of this
individual seemed formed after the female, and
the lower half after the male type, the larynx
and mammae being quite feminine, the face
shewing no appearance of beard, and the arms
being delicate and finely rounded, while the
pelvis was narrow, and the thighs were marked
and angled as in man. In a case described by
Schneider,* the reverse held true, the bust
being male with a strong beard and large
thorax, and the pelvis being large and distinctly
female. A more mixed combination of the
secondary sexual characters has been already
described as existing in the cases detailed by
Ricco, Mayer, Arnaud, Bouillaud, &c.

One side of the body has been sometimes
observed to be apparently formed in one or
more of its parts on a sexual type different
from that of the same parts on the opposite
side. Girald, in his Topography of Ireland,f
mentions a reputed female, who had the right
side of the face bearded like that of a man,
and the left smooth like that of a woman.
Mr. King J has described an interesting in-
stance of hermaphroditic malformation in an
individual whose general character was mas-
culine, but with the pelvis large and wide;
the left testicle only had descended into the
groin, and the mamma of this side was small
comparatively to that of the opposite or right
side.

In a hind mentioned by Mr. Hay,§ and
which, he believed, had never produced any
young, one of the ovaries on dissection after
death was found to be scirrhous. The animal
had one horn resembling that of a three years-
old stag on the same side with the diseased
ovary ; there was no horn on the opposite side.
Bomare|| has given a similar case in the same

1742; Sinnibaldus, Geneanthrop. torn. iv. p. 456;
Alex. Benedictus, Anatom. Corp. Hum. lib. iii.
p. 595 ; Winslow, Anatomy, vol. ii. p. 214 ;
Deusing, De Lacte, p. 327 ; Kyper, Anthropo-
logia, lib. i. p. 490; Buffon, Hist. Nat. torn. ii.
p. 543 ; Bishop of Cork, Phil. Trans, vol. xli.
p. 813; Humboldt, Personal Narrative, vol. iii.
p. 57 ; Franklin, First Expedition to the Polar
Seas, (London, 1823,) p. 157.

* Kopp's Jahrbuch der Staatsarzneikunde, Bd. x.
8. 134.

t Topog. Hibernian, in Camden's Angl. &c.(1603),
part ii. p. 724.

J London Med. Repository for 1820, vol. xiii.
p. 87.

§ Linnaean Transactions, vol. iii. p. 356.

f| Journ. de Phys. torn. vi. p. 506.

IIERMAPHRODITISM.

721

animal, where a single horn was present, situ-
ated also on the same side with the diseased
and degenerated ovary; and Russell* states,
as the result of his experiments on castration
in the deer, that when lie removed one testicle
only from the animal, the horn on the opposite
side was the more completely developed of the
two. Azaraf observed in two birds the right
side of the tail to possess the characters of the
male, and the left those of the female.

In the hermaphroditic lobster previously al-
luded to as described by ISicholls, the general
external configuration of the body was, like
that of the sexual organs, perfectly female on
one side, and perfectly male on the other.

It is principally, however, among herma-
phroditic insects that a difference of sexual
type in the general conformation of the oppo-
site sides of the body, and of its individual
parts, has been observed ; and this malforma-
tion is the more striking and easy of obser-
vation in this class of animals, on account of
the great differences in colour, size, and form
respectively presented by the antennae, wings,
and other parts of the body of the males and
females of the same species.

Lateral hermaphroditism of the body in In-
sects has been most frequently observed by
Entomologists amongst the class Lepidoptera.
It has now been remarked in the following
species: — in the Argynnis paphia, Lyctena
alexis, Satumia pyri, Endrowis versicolor, and
Harpya vinula (Ochsenheiraer) ; in the Gas-
trophaga jnedicaginis and Lycgna adonis
(Rudolphi) ; in the Liparis dispar (Schaefer,
Ochsenheimer, and Rudolphi) ; in the Sa-
turnia Carpini (Capieux, Ochsenheimer, and
Rudolphi); iniheGastrophagaquerci/blia (Hett-
linger and Rudolphi); in the Gastrophaga pini
(Scopoli); in the Gastrophaga crattegi (Esper);
in the Sphinx convolvuli (Ernst); Sphinx populi
(Fischer and Westwood) ; Papilio polycaon
(Macleay); Polyommatus alexis (Entomolog.
Mag. vol. iii. p. 304); Bombyx castrensis
(Duval) ; in the Argynnis paphia (Allis) ;
in the Vanessa atalanta (Schrank and Germar);
and in the Vanessa antiopha and Deilephila
euphorbia (Germar). Klug and Germar have
recorded two instances of it among the Cole-
optera, the former in the Luc anus cervus, and
the latter in the Melolontha vulgaris ; and Mr.
Westwood mentions a third case in the large
water-beetle ( Dyticus marginalia), as con-
tained in Mr. Hope's collection, and has seen
a fourth in the stag-beetle ( Luc an us ctrvus).

Out of twenty-nine recorded cases of lateral
hermaphroditism in Insects, in which the
sexual characters of each side are distinctly
specified, we find that in seventeen instances
the right side was male, and in twelve female.
Burmeister alleges that in by far the majority
of cases the right side is male, and the left
female, — a statement in which Meckel co-
incides, while Westwood maintains the reverse.
The cases we have ourselves collected are cer-
tainly numerically in favour of the former

* Economy of Nature in Glandular Diseases,
t Kob's Dissert, de Mutatione Sexus, p. 19.
VOL. II.

opinion, but the data are as yet so few, and
the difference so trifling, as not to warrant us
to come to any decided conclusion on this
point.

In some instances we find among insects an
imperfect lateral hermaphroditism consisting of
some parts of one side, as of one or more of the
wings, palpi, or antennae being formed according
to a different sexual type from the same parts
of the opposite side, and from the general body
of the animal. Thus in the Melitcea described
and dissected by Rlug (see Lateral Herma-
phroditism) the general form of the insect was
male, but the left eye, palpus, antenna, and left
sexual fang were smaller than in individuals
belonging to this sex; the left antenna was
annulated with white and yellow at the apex,
while the right was of one colour; the general
form of the abdomen was male but somewhat
thick, and the wings were all equal and male.

In a Pontia duplidice mentioned by Rudol-
phi, and which in its general external characters
was female, the right anterior wing was formed
after the male type, and the sexual organs also
resembled those of the male.

Ochsenheimer mentions one Gastrophaga
quercus with the body, and the antenna? and
wings on the left side female, and the right wings
male ; and a second with the body and the
right side female, and the left side and two an-
tennae male, the latter being brown and pecti-
nated.

In this imperfect variety of lateral herma-
phroditism, the malformed wing, antenna, or
palpus is sometimes formed after one sexual
type and coloured after another. In a male
Melitcea phaebe noticed by Germar, the right
wings and antenna were female in regard to size,
but male in respect to colouring and markings.
In a female Deilephila galii, he found the left
antenna and palpus of the small size of the male,
but agreeing in colouring and markings with the
corresponding female parts on the right side.
In a Pontia cardamines, which was male in
all its other characters, Ochsenheimer observed
the right superior wing marked as in the
female, and he mentions another individual of
the same species which had a female form with
some male colours.

In another variety of insect hermaphroditism
the sexual difference is sometimes, as we have
already noticed in regard to the human subject,
expressed not by a lateral, but by a longitudinal
sexual antagonism, or, in other words, the
anterior and posterior parts of the body are
formed after the two opposite sexual types.
Thus in a Saturnia carpini described by
Ochsenheimer, the antennae were male, the
superior wings male in form, but coloured as
in the female, and the posterior wings, with the
exception of a reddish brown spot upon the left,
were, with the body and other parts, female.

Lastly , in a third variety of external hermaphro-
ditic conformation in Insects, we find the char-
acters of the two sexes mixed up and crossed in
different irregular combinations upon the body
of the same individual. In a Gastrophaga
castrensis described by Rudolphi, and where
the male type predominated, with a tendency,

3 B

722

HERMAPHRODITISM.

however, in all parts to the female form, the
right antenna and the wings on the opposite or
left side were distinctly female, while the left
antenna and right wings were entirely male,
the latter being only somewhat larger than in
male insects, and the colours brighter than in
the female. In a Bombyx castrensis alluded
to by Westwood, the wings on the right side,
and the antennae and abdomen of the left, were
those of a male, while the left wing, right an-
tennae, and right side of the abdomen were
those of a female.

GENERAL SUMMARY WITH REGARD TO THE
NATURE OF HERMAPHRODITIC MALFORMA-
TIONS.

1 . Of the varieties of spurious hermaphro-
ditism.— On some of these varieties it is un-
necessary for us to dwell here. The first
species of spurious male hermaphroditism, or
that arising from extroversion of the urinary
bladder, is elaborately discussed elsewhere
(see BLADDER); and two others, namely, the
second female species consisting of prolapsus
of the uterus, and the second male consisting of
an adhesion of the penis to the scrotum, seem
both referable to the head rather of disease than
of original malformation. This latter indeed ap-
pears in all probability only an effect or result of
adhesive inflammatory action in theaffected parts
during embryonic or foetal life. Both of the two
remaining forms of spurious hermaphroditism,—
viz. those consisting of hypospadic fissure of the
urethra, scrotum, and perinaeum in the male,
and of abnormal magnitude of the clitoris in the
female, — seem readily explicable upon the doc-
trine of arrestment and anormality in the deve-
lopment of the malformed parts.

We have already described at sufficient
length the process of development of the dif-
ferent copulative organs, and have shewn that
those various degrees of hypospadic malforma-
tion which constitute the common form of
spurious hermaphroditism in the male, may be
traced to arrestment of this process at various
periods or stages of its progress. And we may
here remark that the earlier this arrestment
occurs, the distinction of the true sexual type of
the malformed organs will always be the less
marked, because the younger the embryo, and,
on a similar principle, the lower we descend in
the scale of animal existence, we find the dif-
ferences between the organs of the two sexes
proportionally the less pronounced, until at
last we arrive at that primitive type in which
these organs present altogether a common, neu-
tral, or indeterminate character.

We have also already shewn that at a certain
early stage of the development of the female
organs, the female clitoris holds the same, or
nearly the same relatively larger size to the
whole embryo as the penis of the male, and
that so far we may consider the occasional
occurrence of spurious hermaphroditism from
magnitude of the clitoris, and its resemblance
in this respect to the male organ, as a perma-
nent condition of a type of embryonic structure
that is normally of a temporary or transitory
existence only. But besides this permanence

of the embryonic type of the clitoris, we must
farther, in all the more complete instances of
spurious female hermaphroditism, admit an
excess of development in the malformed
external sexual parts, and more particularly in
the line of the median reunion of the two
primitive lateral halves or divisions of these
parts. In this way the vagina (a remnant in the
female of the primitive perinseal cleft or
fissure) is often in such cases more or less con-
tracted and closed, so much so indeed in some
instances as to leave only, as in the male, a
small canal common to the genital and urinary
passages. If the median junction is extended
still farther, this canal comes also to imitate the
male urethra in this respect, that it is united or
shut up below in such a way as to be carried
onward to a greater or less length, and in a
more or less perfect condition along the under
surface of the enlarged clitoris ; and occasion-
ally the male type of structure is still more
completely repeated in the female organization
by the median reunion of the two labia, giving
the appearance of the united scrotum and closed
perinaeum of the opposite sex.

If we divide the whole sexual apparatus of
the male and female into three corresponding
transverse spheres or segments, — the first or
deep parts including the testicles and ovaries,
the second or median comprehending the male
seminal canals and prostate gland, and the
female oviducts and uterus, and the third or
external embracing the copulating organs of the
two sexes, — we shall find that, relatively
speaking, the deep and the external spheres are
naturally most developed in the male economy,
while the median, comprising the uterus, (the
principal and most active organ in the female
reproductive system,) is developed in the
greatest degree in that sex. In malformed
females presenting a spurious hermaphroditic
character, this important portion of the female
sexual organization is, in general, either itself
in some respects malformed, or, from the
structure of the other parts of the sexual appa-
ratus being imperfect, its specific importance in
the economy is cancelled, and therefore the
energy of development takes the same direction
as in the male, being expended upon the more
complete evolution of the organs of the external
and deep spheres. Hence the greater size of
the clitoris, and the greater development which
we have just now pointed out, in the median
line of reunion of the external sexual parts ;
and hence also the occasional though rare
occurrence, in the same cases, of the descent of
the ovaries through the inguinal rings into the
labia, — an anomaly that certainly consists in
a true excess of development, and which we
cannot but regard as interesting, both in this
respect, and as affording a new point of
analogy between these organs themselves and
the male testicles.

There is another and equally interesting point
of view in which we may look upon this sub-
ject. Not only are the forms of spurious her-
maphroditism which we have been considering,
capable of being traced backward to certain tran-
sitory types of sexual structure in the embryos

HERMAPHRODITISM.

723

of those animal species in which the malfor-
mations in question occur, but they may be shewn
also to present in their abnormal states repe-
titions of some of the normal and permanent
conditions of the sexual organs in various species
of animal beings placed lower in the scale of
life. Thus the occasionally imperforate penis
of the male hermaphrodite has been supposed
to have an analogue in the naturally solid penis
of some of the species of the genera Doridium
and Hyalaa* Its more or less grooved or hy-
pospadio condition is similar to the natural
type of the same part in some hermaphrodite
Mollusca, as in the Planorbis and Murex :f
in its occasional diminutive size it approaches
the general smallness of the partially fissured
penis of most birds and reptiles ; and we find
it in the Rodentia and Marsupiata tied down
by a short prepuce in a way analogous to what
is seen in some cases of severe hypospadias.
In the sloth ( Bradypus tridactylus) the penis
is small and grooved in its lower surface, and
has the urethra opening at its base ;\ and in
several of the male Rodentia the scrotum is
also cleft, and has its two opposed surfaces
smooth, humid, and free of hair, as in most
cases of hypospadic hermaphroditism in man.
In Ophidian and in most Saurian Reptiles, the
male seminal ducts open at once externally, as
in some male hermaphrodites, at the root of the
fissured penis.

The fact of the testicle some time remaining,
in cases of hermaphrodite formation in the
human subject, within the cavity of the ab-
domen, presents to us in a permanent state
their original but changeable position in the
early foetus, and at the same time affords a
repetition of their normal situation, in almost
all the lower tribes of animals, and in the
Cetacea, Amphibia, Edentata, and some Pa-
chydermata, as the Cape Marmot (Hyrax)
and Elephant, among the Mammalia.

The malformed clitoris in instances of
spurious hermaphroditism assumes also, in its
abnormal state, types of structure that we find
as the normal condition of the organ in various
inferior animals. Thus in female Cetacea and
Rodentia, and in the animals included in
Cuvier's order of Carnassiers, but more par-
ticularly among the Quadrumana, the clitoris
retains as its permanent normal type that
relatively larger size which we observe in the
early foetus, and in female hermaphrodites in
the human subject : and further, as is some-
times seen in such malformed individuals, the
clitoris becomes partially traversed by the
urethra, as in the Ostrich, Emu,§ and Ant-
eater ;|| and in the Loris (as we have noticed in
a preceding page) and Maki, it is completely
enclosed, like that of the male, in the body of

* Burdach's Physiologie, Bd. i. $ 132, p. 231.

t Tiedemann's Zeitschrift fuer Physiologie, Bd.
L s. 15, or Cuvier, Anat. Comp. torn. v. p. 182.

$ Meckel, Beitraege zurvergleichtnden Anatomic,
Bd. ii. cap. i. p. 125.

yDuvier, Anat. Comp. t. v. p. 129.
Vleckel, Archiv. fuer die Physiologie, Bd. v.
.

the organ, forming a continuous and perfect
canal through it.

\Ye may here further observe, (though the
illustrations should more properly belong to the
next section,) that in cases of true hermaphro-
ditism also in man and quadrupeds, as well as
in the above spurious varieties, there may be
often traced in some portions of the abnormal
structures a sexual type bearing a greater or
less analogy to the corresponding parts of
those inferior animals that are naturally andro-
gynous. Thus, in instances of true hermaphro-
ditism, the orifices of the sexual ducts or
passages occasionally open into a common
cavity, as is normally the case in some species
of Doridium, Heliv, and other Mollusca ; or the
female oviducts or Fallopian tubes, and the
male vasa deferentia, run closely alongside of
each other without any communication between
their canals, as in the Alypsia and most Gas-
teropoda. Indeed the occasional co-existence
even of both testicles and ovaries in individuals
among the higher animals would be only a
repetition of, or retrogression to, the normal
sexual type of those genera of animals that we
have just named, and of the Planaria, Ces-
toidea, and other natural hermaphrodites.

In this way we see, that, (as in many other
monstrosities,) the several varieties of malfor-
mation in the sexual organs occurring in
spurious human hermaphroditism do not con-
sist of the substitution of an entirely new and
anomalous type of structure, but are only
repetitions of certain types of the same organs
that are to be met with both in the human
foetus and in the inferior orders of animal
beings. The investigation of the whole subject
shews us in reference to the sexual organs,
what is equally true in regard to all the other
organs of the body, — that their different stages
of development in the embryos of man
and of the higher orders of animals cor-
respond to different stages of their deve-
lopment in the series of animal beings
taken as a whole ; so that here, as elsewhere,
the facts of Comparative Anatomy are repro-
duced in those of Embryology, and both are
repeated to us by nature on a magnified scale
in the anatomy of the malformations of the
part, — a circumstance amply testifying to the
intimate relations which subsist between Com-
parative Anatomy, the anatomy of Embryonic
Development, and that of Monstrosities.
Indeed proportionally as our knowledge of
malformations has increased, it has shewn us
only the more strongly that the laws of forma-
tion and malformation, — of normal and abnor-
mal development, are the same, or at least that
they differ much more in degree than in essence,
and that the study of each is calculated recipro-
cally to illustrate and to be illustrated by the
study of the other.

2. Nature of true hermaphroditic malfor-
mations.— Of the nature of local malforma-
tions by duplicity, we at present possess much
less precise knowledge than of those of simple
defect or simple excess of development ; but
there are certain facts ascertained with regard

3B2

724

HERMAPHRODITISM.

to the formation of the sexual organs, which
may enable us to make an approach at least to
accurate ideas of the character and origin of
those anormalities that constitute the several
varieties of true hermaphroditism. These facts
relate to the interesting subject of the unity of
structure which is manifested in the correspond-
ing male and female reproductive organs of the
human subject, and of other species of bisexual
animals.

By several of the Greek, Roman, and Ara-
bian physiologists,* the respective organiza-
tions of the two sexes were considered as in
some degree typical of one another, the female
being regarded as an inverted male, with the
testicles and penis turned inwards to form the
ovaries and uterus. This doctrine of analogy
between the male and female sexual organs
has, with various modifications, been very ge-
nerally admitted by modern physiologists, and
in some of its bearings it has been made, more
particularly of late years, the subject of consi-
derable discussion. The testicles are still re-
garded as organs which correspond with the
ovaries in their original situation, in their vas-
cular and nervous connections, and in their re-
lative sexual functions. The recent progress
of the anatomy of the development of the em-
bryo has also shewn that the two organs cor-
respond in their primitive origin. It is now
well ascertained that the large masses occupy-
ing each side of the abdomen of the embryo
at an early stage of development, and which
Rathke has named the Wolffian bodies after
their illustrious discoverer, form, in Birds and
Mammalia at least, the primordial matrices
upon which the urinary and genital organs are
developed. On the inner side of each of these
matrices a small body is early developed, which
seems to become afterwards either a testicle or
an ovary, according to the particular ulterior
sexual type which the embryo assumes.

In further following up the analogy of struc-
ture between the organs of the two sexes, the
vasa deferentia of the male are generally com-
pared to the Fallopian tubes of the female,
the scrotum to the external labia, the body of
the penis to the clitoris, and its corpus spon-
giosum, or, according to others, its prepuce, is
regarded as corresponding in type with
the female nymphae. A considerable dif-
ference of opinion, however, still prevails
as to the prototype of the female uterus in the
male system. Some anatomists, as Burdach,
Steghiener, and Blainville, regard the uterus
and male vesiculae seminales as corresponding
parts ; while others, as Meckel, Carus, Schmidt,
Ackermann, and Serres, compare the uterus to
the male prostate. A sufficient number of
facts seems still wanting to determine the accu-
racy and justness of either of these analogies.
There are instances of malformation on record
which appear to favour both opinions, and there
are other cases which almost incline us to be-

* Aristotle, Hist. An. lib. i. 17. Galen, De Semine,
lib. ii. & De Usu Partium, c. i. Rhases, De Re
Medica, lib. i. cap. 26. Avicenna, De Membris Ge-
neral, lib. iii. 21, &c.

lieve that the vesiculse seminales correspond to
the fundus or body of the uterus in the human
subject, and to the cornua uteri in quadrupeds;
while the prostate represents in the male struc-
ture the lower portion or cervix of the same
organ. The phenomena of the development
of the reproductive organs in the embryo will,
when more fully investigated, probably serve to
clear up this question.

M. Geotfroy St. Hilaire has propounded
views of the analogy of the male and female
organs in some respects different from the above.
He divides the uterus of the human subject
into the body and the upper part or fundus, the
latter corresponding to what constitutes the
cornua uteri in the human embryo, and in adult
quadrupeds. Further, believing that in the
determination of all analogies in type and
structure between different organs, the origin
and course of the bloodvessels supplying the
part ought to be our principal criterion, he has
been led, by the study of the distribution of the
branches of the hypogastric arteries, to consider
the body of the uterus and the vesiculse semi-
nales as repetitions of each other in the two
sexes ; and, contrary to the opinion of most
anatomists, he conceives that the male vasa
deferentia strictly correspond with the fundus
or cornua uteri, and that the epididymis repre-
sents a coiled-up Fallopian tube, or in other
words that the Fallopian tube is an unrolled
epididymis. M St. Hilaire has offered the
following table to shew what he conceives to
be analogous organs in the two sexes : — *

In the male. In the female.

Testicle = Ovary

Epididymis =5 Fallopian tube

Vas deferens. = Cornu of the uterus

Vesicula seminalis= Body of the uterus.

Sheath of the penis = Vagina

Penis = Clitoris

In tracing out the analogies between the
male and female parts, the mode in which we
ought to consider the female vagina has given
rise to some diversity of opinion. From the
above table it appears that M. St. Hilaire con-
siders it to be represented in the male organiza-
tion by the sheath of the penis, but we are cer-
tainly inclined to view it in a different light,
and to regard it as a part in so far peculiar to
the female, that it consists of a permanent
condition of that urino-gemtal perinseal fissure
that we have already described as existing at a
certain period in the embryos of both sexes,
and which is latterly shv.t up in the male, or,
speaking more accurately, it is contracted into
what forms the pelvic portion of the male
urethra.

If this were a fit opportunity for following
out the consideration of the unity of type be-
tween the male and female reproductive organs,
it would be easy to shew the justness of those
greater analogies that we have mentioned, by
pointing out other numerous minor, but still
strong points of correspondence manifested in

* Phil. Anat. torn. i. (1822,) p. 471.

HERMAPHROD1TISM.

725

the abnormal conditions and localities of the
ovaries and testicles in the higher animals, and
in their conformity of structure in some of the
lower. Thus among Insects, in the gemis Li-
bt'llula the long cylindrical testes of the males
correspond with the long-shaped ovaries of the
females; in the Locusta and Gryl/otalpa,
there are ramose bunched testicles with analo-
gous fasciculated ovaries ; in the Lumellicornia
we find compound radiating and united testes,
with similar radiating and united ovaries ; and
sometimes, as in the genera Melolontha and
ZVieA*us,the number of the single bodies in the
testicles corresponds with the number of the
oviducts.*

We have already, when considering spurious
hermaphroditism in the female, mentioned
several facts illustrative of the analogical pe-
culiarities in structure between the male penis
and female clitoris in some species of animals ;
and Burmeister.f who regards the ovipositors
and stings of female insects as corresponding
to the clitoris in the female Vertebrata, has
pointed out a remarkable conformity of struc-
tural type between its valves and those of the
penis of the male of the same species.

Some organs that are, as far as regards their
functions, peculiar and essential to one sex
only, are nevertheless found to be repeated in
the opposite sex in the form of an analogous
rudimentary type of structure. Thus, in the
male we may observe the unity of sexual struc-
ture maintained in the presence of the rudi-
ments of the mammary gland, which is func-
tionally an organ of the female system only. In
the human subject, and in animals whose females
have pectoral mamma:, these organs occupy the
same position in the male; while in those
species of quadrupeds in which they are placed
in the inguinal region, we find them in the
corresponding males forming the scrotum or
bags for containing the testicles. Hence, as we
have already seen, the testicles, in cases of mal-
formation in these animals, are often laid upon
or imbedded in the udder. In the same way
in the Marsupiata, the bone which the female
has for supporting the marsupium is repeated
in the organization of the male, although in the
latter we cannot conceive it to serve any possible
use.J

In the female also we observe in some points
a similar disposition to the rudimentary repe-
tition of parts that are essential or peculiar
only to the male organization, as in the repeti-
tion in the clitoris of some female Rodentia, of
the penis-bone of the male, and in the forma-
tion of rudimentary forms of those processes
of peritonaeum which constitute the tunica
vaginales. We are ourselves inclined also to
regard the common crescentic form of the hy-
men of the human female in the same light,§

* Burmeister's Entomology, § 154. p. 222.

f Lor. cit.

j Home's Lect. on Comp. Anat. vol. ii. pi. v.

§ Burdach (Phys. § 137,) considers the small
cutaneous fold situated at the orifices of the vasa
deferentia, and Stiebel the membrane placed at the
extremity of the urethra (Meckel's Archiv. fur
Physiol. Bd. viii. s. 207,) as the analogue in the
male for the female hymen.

and to consider it merely as an abortive attempt
at that closure of the perinoeal fissure which
we have already described as effected at an
early period in the male embryo — an opinion
in which we conceive we are borne out both by
the history of the development and the study
of the malformations of the external sexual
parts in the female.

M. Isidore St. Hilaire read, in 1833, to the
French Academy a memoir,* in which, follow-
ing up the doctrine of his father with regard to
the determination and distinction of the type of
parts by the particular vessels distributed to
them, he endeavoured to shew some new
points of analogy between the male and female
organs, and to develop new views with regard
to the origin and particular varieties of herma-
phroditic malformations. With Burdach, he
divides the whole reproductive apparatus of
either sex into three transverse spheres and
into six portions or segments in all, or three on
each side, viz., 1 and 2, the deep organs, in-
cluding the male testicles and female ovaries ;

2 and 3, the middle organs, or male prostate
and vesiculae seminales, and female uterus ;

3 and 4, the external organs, comprehending
the penis and scrotum of the male, and the
clitoris and vulva of the female. Each of these
portions or segments is, M. St. Hilaire points
out, supplied by an arterial trunk peculiar to
itself, and the corresponding organs of the male
and female by corresponding arterial branches,
as the deep organs of both sexes by the two
spermatics, the middle by branches of the two
hypogastrics, and the external by some other
hypogastric branches, and by the external pu-
dics. This circumstance, he conceives, renders
all the segments in a certain degree independ-
ent of the others, both as regards their develop-
ment and existence, and allows of the occa-
sional evolution of any one or more of them
on a type of sexual structure, different from
that upon which the others are formed in the
same individual.

Though assuredly we cannot subscribe to
the speculations of the elder St. Hilaire, that
the development in the embryo of male testi-
cles or female ovaries, and consequently the
whole determination of the sex, is originally re-
gulated by the mere relative angle at which the
first two branches of the spermatic arteries
come off, and the kind of course which they
followjf (more particularly as it is admitted by
most physiologists that the bloodvessels grow,
not from their larger trunks or branches towards
their smaller, but from their capillary extremi-
ties towards their larger branches,) yet we
believe that the doctrine of the comparative
independence of the different segments of the

* Arch. Gen. de Med. (1833) torn. i. p. 3O5.

t Anat. Phil. torn. i. p. 359. . . " L'ordre
de variations des sexes tient a la position d'un
artere. . . Le plus ou le moms d'ecarlement
des deux branches spermatiques motive effective-
ment cette preference. Queles deux branches de
1'artere spermatique descendent parallelement et de
compagnie, cette circonstance, je le repete, cette
circonstance donne le sexe male ; qu'elles s'ecar-
tent a leur point de partage, nous avons le sex« fe-
melle."

726

HERMAPHRODITISM .

reproductive organs pointed out by the son is
in its general principles correct. At the same
time we would here remark that we conceive
the doctrine would have been founded more on
truth if the influence of the nervous branches
supplying the different reproductive organs had
been taken into account along with that of
their arterial vessels, because, as we shall
point out when speaking of the causes of her-
maphroditism, there appears to be some con-
nection between the state of the nervous sys-
tem and the degree or condition of sexual de-
velopment.

The consideration of the preceding ana-
logies in structure between the male and
female organs is interesting in itself, and, as far
as relates to our present subject, important in
this respect, that it enables us in some degree
to understand how it happens that, without any
actual monstrous duplicity, we should some-
times find, in an organization essentially male,
one or more of the genital organs absent and
replaced by an imperfect or neutral organ, or
by the corresponding organ of the opposite
sex, and vice versa ; inasmuch as it shews us
that the moulds in which the analogous organs
of the two sexes are formed are originally the
same. Hence there is no difficulty in con-
ceiving that, in the body of the same individual,
the primitive structural elements of these parts
should occasionally, in one or more points or
segments, take on, in the process of development,
a different sexual type from that which they
assume at other points. Indeed some physi-
ologists, as we shall immediately see, deny
that the most complete hermaphroditic malfor-
mations ever consist of anything except such a
want of conformity between the sexual type of
different portions of the reproductive appa-
ratus.

If each of the six segments (and we believe
that their number might be shewn to be really
greater than this,) is thus an independent cen-
tre of developmeut in the formation of the
sexual apparatus, and is consequently liable
also in abnormal cases to have its own parti-
cular malformations, and to assume, either
alone or along with some of the other seg-
ments, a sexual type different from the re-
mainder, it is evident that we may have as
many varieties of true hermaphroditism, with-
out any real duplicity, as it is possible to con-
ceive differences of arrangements among these
six segments. Again, however, one or more
of these segments may preserve from a deve-
lopment its original indeterminate or neutral
sexual type, while the others are variously
formed either upon one or upon both sexual
types; or one or more of the segments may,
by a true malformation by duplicity, have
evolved within them the corresponding organs
of the two sexes ; and if we consider the dif-
ferent arrangements of double and single
sexual parts that might thus occur in the six
separate segments, we may gain some idea of
the great diversities of structure in the sexual
parts that are liable to be met with in instances
of true hermaphroditism.

The above forms, as it appears to us, the

most sound and rational solution of the nature
and origin of many forms of true hermaphro-
ditism which physiological science is capable
of affording, upon our present limited know-
ledge of the laws of development ; and its
application to the explanation of the different
varieties of lateral, transverse, and vertical her-
maphroditism is so obvious as only to be
required to be alluded to. It offers to us,
however, no insight into the probable origin of
those varieties of double hermaphroditism in
which there is an actual co-existence upon one
or upon both sides of the body, or, in other
words, in the same segment of the sexual
apparatus, of both the corresponding male and
female organs. We can only refer all such
instances to the laws which regulate the occa-
sional production of local duplicities in diffe-
rent other organs of single bodies, and at the
same time confess our present ignorance of
what these laws are. We know that various
individual muscles, nerves, &c. are not unfre-
quently found double, and that in the internal
organs of the body examples of duplicity in
individual viscera are occasionally, though
rarely, observed in the heart, tongue, trachea,
O3sophagus, intestinal canal, &c. In the
several organs composing the reproductive
apparatus, instances of similar duplicity would
seem to be even more common than among
any other of the viscera. Examples of three
mammee upon the same person are mentioned
by Bartholin,* Borelli,f Lanzoni,]; Drejer,§
Robert,|| Petrequin,^ and others;** and cases
in which the number of these organs was in-
creased to four have been recorded by Faber,ff
Gardeux,fi Cabroli,§§ Lamy,||[| Tiedemann,H1[
Champion,*** Sinclair,^ R. Lee,JU and
Moore.§§§ An instance in which jive mam-
mae even existed upon the same woman is re-
ported to have been seen by Gorre.|||||| Valen-
tin 1fH1[ and Gunther**** have recorded sup-
posed cases of duplicity in the male penis; and
Arnaudtftt has related an example of an ana-
logous malformation in the female clitoris.
WeberJJJJ met with a double vesicula seminalis

* A eta Med. Hafn. torn. iii. obs. 93.
t Observ. Rar. cent. i. p. 55.

Eph. Nat. Cur. Dec. ii. Ann. v.'obs. 55.
Arch. Gen. de Med. torn. xvii. p. 88.
Journ. Gen. de Med. torn. c. p. 57.
Gazette Medicale for April,j 1837. Three
distinct mammae in a father, and in his three sons
and two daughters.

** Diet, des Sc. Med. torn, xxxiv. p. 529.
tt Eph. Nat. Cur. Dec. i. Ann. ii. p. 346.
** Journ. de Med. de Corvisart, torn. ix. p. 378.
Obs. Anat. vii.
Fantoni Anat. p. 267.

H Zeitschrift fur Physiologic, Bd.v. s. 110. One
case with three, and three with four nipples. In
one case the malformation was hereditary.

*** Diet, des Sc. Medic, t. xxx. p. 377. See
also p. 378.

ttt Statistical Account of Scotland, xix. p. 288.

\\\ London Med. -Chirurg. Trans, vol. xxi. p. 266.

§§§ Lancet for February 24, 1838.

JIIIJI Diet, des Sc. Med. torn, xxxiv. p. 529.

i[1IH Eph. Nat. Cur. Dec. iii. Ann. iii. obs. 77.

**** Cohen vom Stein, Halle, 1774, p. 107.

tttt Mem. de Chir. torn. i. p. 374.

Jf It Salzburg Medicinische Zeitung, 1811, s. 188.

HERMAPHRODITISM.

727

on each side ; and Hunter* alludes to the occa-
sional occurrence of an imperfect supernumerary
vas deferens. In 1833 a case of a double human
uterus, furnished with four Fallopian tubes and
four ovaries, was shewn by Professor Moureau
to the Academic de Medecine.f BlasiusJ
dissected the body of a man on whom he
detected the co-existence of three testicles ; the
additional testicle was of the natural form and
size, and was furnished with a spermatic artery
and vein that joined in the usual manner the
aorta and vena cava ; it lay in the right side of
the scrotum. Arnaud found, on dissection,
three testicles in a dog; the third was placed
in the abdomen, and of the natural consistence,
figure, and size ; it was furnished with a vas
deferens.§ Other instances of triple and
quadruple testicles of a more doubtful charac-
ter, inasmuch as the observations made during
life were not confirmed by dissection after
death, are related by Voigtel,|| Sibbern,5[
Brown,** Rennes,ft and others.Jt Scharff§§
even gives an alleged case of a man with five
testicles, three of which are stated to have
been well formed, while the other two were
much smaller than natural. And, lastly,
Loder|||| is said to have exhibited to the Gcettin-
gen Academy drawings taken from the body of
a male infant, on whom all the sexual apparatus
existed double, there being two penes, a double
scrotum, and urinary bladder, and, as it was
supposed, four testicles.

In all the preceding instances the local
duplicity of the particular reproductive and
other organs adverted to existed independently
of any duplicity in the body in general, or in
any other individual parts of it. And if we
once admit, (what the preceding instances will
scarcely allow us to deny,) that there may
occur a duplicity of some of the male sexual
organs in a male, or of some of the female
sexual organs in a female, it is certainly easy
to go one step farther, and admit that the
double organ or organs may, however rarely,
be formed in other instances upon an opposite
sexual type. Indeed all our knowledge of the
unity of structure and development between
the various analogous male and female repro-
ductive organs, as well as the fact of the occa-
sional replacement of an organ of the one sex
by that of the other in cases in which the
sexual type is entirely single (as seen in
instances of lateral hermaphroditism), would
lead us a priori to suppose that, if a local
duplicity in any of the sexual organs was liable
to occur, this duplicity would sometimes shew
itself in the double organs assuming opposite

* Bell's Anatomy, vol. iii. p. 428.
t Journ. Hebdom. torn. x. p. 168.
j Obs. Med. pars iv. obs. 20.
Mem. de Chirurg. s. i. p. 131.
Handbuch der Path. Anal. Bd. iii. s. 393.
A eta Hafn. torn. i. p. 320.
** New York Medical Repository, vol. iv. p. 801.
ft Arch. Gen. de Med. t. xxiii. p. 17.
j+ See Haller's El. Phys. torn. v. p. 411, 12.—
and Arnaud's Chem. de Chirurg. t. i. p. 128, &c.
*e Eph. Nat. Cur. Dec. iii. Ann. v. vi. obs. 89.
Gbttingen Anz. 1802, p. 4$6.

sexual characters, and thus constituting some
of those varieties of double or vertical her-
maphroditism that we have tilready had occa-
sion to describe.

In the preceding observations we have pro-
ceeded upon the opinion commonly received
by physiologists, of the fundamental unity of
sex among all individuals belonging to the
higher orders of animals; or, to express it
otherwise, we have assumed that each individual
is, when normally formed, originally furnished
with elemental parts capable of forming one
set of sexual organs only. We do not here
stop to inquire whether this single sexual type
is, in all embryos, originally female, as main-
tained by Rosenmiiller, Meckel, Blainville,
Grant, and others; or, of a neutral or inter-
mediate character, as supposed by the St.
Hilaires, Serres, Ackermann, Home, &c., and
as we are certainly ourselves inclined to believe
it.* On this subject, however, a physiological
doctrine of a different kind has been brought
forward by Dr. Knox, and this doctrine is so
intimately connected with the question of the
nature and origin of true hermaphrodites, that
we must here briefly consider it.

Dr. Knox,f in conformity with some more
general views which he entertains on tran-
scendental anatomy, is inclined to regard the
type of the genital organs in man and the higher
animals, as in the embryo, originally hermaph-
roditic, or as comprising elementary yet dis-
tinct parts, out of which both sets of sexual
organs could be formed ; and he believes that,
owing to particular but unknown circum-
stances, either the one or the other only of
these sets of elements comes to be evolved in
the normal course of development. In those
abnormal cases, again, in which, as in instances
of double hermaphroditism, more or fewer of
both sets of genital organs are present upon
the same individual, he maintains that this is
not to be considered as a malformation by
duplicity, but is only a permanent condition of
the original double sexual type, and is attri-
butable to the simultaneous development to a

* Meckel (De Duplicitate Monstrosa, p. 14),
and Andral (Anat. Path. torn. i. p. 101)* assume
it, after Haller, as a fact, that a much larger pro-
portion of monsters belong to the female than to
the male sex ; and while they attribute this circum-
stance to the genital organs in these beings retain-
ing, from the general defect of development, their
original female sexual character, they at the same
time consider this circumstance to be strongly
corroborative of this particular doctrine. Isid.
St. Hilaire has shewn (Hist, des Anomal. t. iii.
p. 387) that the supposed fact itself does not hold
true in respect to some genera of monsters, and is
even reversed in others ; and he doubts if it be of
such a degree of generality in respect to mon-
sters in general as to merit to be raised into a
teratological law. If the views of Meckel were
correct, we should certainly expect at least that
spurious hermaphroditism, where the development
of the sexual parts is commonly abnormal from
defect, should be much more frequent in the female
than in the male. The list, however, of recorded
cases of it in the latter is, we believe, more than
double the number of it in the former.

t Brewster's Edinburgh Journal of Science,
vol. ii. p. 322.

728

HERMAPHROD1TISM.

greater or less extent both of the male and
female sets of sexual elements.

Tins doctrine of the original but temporary
double sexed character of all embryos derives,
perhaps, its principal support from a source to
which Dr. Knox does not advert, — we mean
the existence of this as the normal and perma-
nent sexual type in most plants and in many of
the lower orders of animals. But this argument
by analogy certainly cannot by any means be
considered as a sufficient basis for the establish-
ment of so broad and important a generalization
in philosophical anatomy. Dr. Knox himself
seems to have been induced to adopt the idea
principally because it afforded (when once
assumed as a fact) a simple and elegant solution,
upon the laws of development, of the occa-
sional occurrence of cases of true hermaphro-
ditism ; and in doing so, he appears to have
proceeded upon the mode in which most such
physiological hypotheses have been made, viz.
by drawing his premises from his deductions
instead of his deductions from his premises.
In the present state, however, of anatomical
and physiological knowledge, Dr. Knox's hypo-
thesis, however ingenious in itself, is one which
we cannot subscribe to ; for first, it is totally
opposed to all the facts which have been ascer-
tained, and all the direct observations which
have been made by llathke, Meckel, Miiller,
Valentin, and other modern anatomists upon
the sexual structure of the embryos of the
higher animals in their earliest state; and,
secondly, if we were to admit it merely as a
probable hypothesis, it is still even in this
respect equally as incapable as the old doctrine
of sexual unity, of explaining all the cases of
malformation by duplicity of the genital organs;
for, as we have already shewn, there are some
apparently well-authenticated instances of the
existence of three or four testicles upon the
same man, or three or four ovaries upon the
same woman ; and in reference to all such cases
we would, if we proceeded upon the same
data and the same line of argument as those
adopted by Dr. Knox, be obliged to suppose
that the original sexual type is not, as he ima-
gines, double only as respects the two sexes,
but double even as respects each sex, and that
all embryos had originally not simply the ele-
ments of two, but those of three or four
testicles and ovaries. In explaining such cases
as those to which we allude, Dr. Knox, on his
own doctrine, must of necessity admit the
existence of a malformation by duplicity of the
sexual organs in question ; and if we grant this
in regard to these instances, it is surely unne-
cessary to invent a particular and gratuitous
hypothesis for the explanation of the analogous
anatomical anormalities observed in hermaph-
roditism. At present we must, we believe,
merely consider the occurrence of anomalous
duplicity of the sexual organs, and of various
other individual parts of the body, as so many
simple empirical facts, of which we cannot, in
the existing state of our knowledge, give any
satisfactory explanation, or, in other words,
which we cannot reduce to any more simple or
general fact; though from the success which

has attended the labours of many modern
investigators in this particular department of
anatomy, it seems to us not irrational to hope
that ere long we may be enabled to gain much
new light upon the question of double her-
maphroditism and the whole subject of mal-
formation by duplicity.

ANATOMICAL DEGREE OF SEXUAL DUPLICITY
IN HERMAPHRODITISM.

Though the cases which we have brought
forward do not present any instances of such
perfect hermaphrodites in the human subject
or in quadrupeds as those which are represented
upon the ancient Greek statues and medals, *
or that have been described and delineated by
Lycosthenes, Pare, Schenkius, and the older
authors on monstrosities, they yet present to
us a sufficient number of instances in which,
in accordance with the definition we have pre-
viously given of true hermaphroditism, there
actually co-existed upon the body of .the same
individual more or fewer of the genital organs
both of the male and female.

From the relations and size of the bony pelvis,
and the fact of the penis and clitoris being re-
petitions only in situation and structure and
organic connections of each other in the two
sexes, it is useless perhaps to expect that we
should ever find in any one case all the parts of
both sexes present at the same time. For
since the male penis is only a magnified condi-
tion of the female clitoris, and since both of these
organs are connected by the same anatomical
relations to the same part of the pelvis, it
would almost require some duplicity in the
pelvic bones themselves to admit of the simul-
taneous presence of both ; and in no authentic
case has any approach to their co-existence upon
the same individual been observed.

Various authors who have written upon the
subject of hermaphroditism have gone so far
as to endeavour to refer all instances of it to
some one or other of those varieties that we
have described under the name of spurious.
Thus, dogmatizing in a spirit of unphilosophical
scepticism, Parsonsf and Hill}; have endea-
voured to shew that all reputed hermaphro-
dites are only malformed females having a
preternatural 'development of the clitoris, and
in some instances with the ovaries descended
into the labia. Others, on the contrary, as

* See Winckelman, Hist, de 1'Art, t. i. p. 364;
andCaylus, Recueil d'Antiquites, t. iii ; Heinrich,
Commentatio qua Hermaphroditorum artis antiquae
operihus illustrium, origines et causae explicantur.
Hamburg, 1805. Blumenbach, in his Specimen
Hist. Nat. Antiq. artis (Goetting, 1808), mentions
and figures (pi. i. f. 5, p. 15), a small ancient sil-
ver cast or impression of a case of hypospadias of
the male genital parts, which he supposes to have
formed a votive offering from some individual mal-
formed in the manner represented.

t Enquiry into the nature of Hermaphrodites,
p. 145. We would particularly point out the cases
quoted by Dr. Parsons at p. 14, 26, 30, 88, 95, 130,
&c. of his able essay as directly contradictory of
his own doctrine, or as instances of hermaphroditic
appearances in persons not of the female but of the
male sex.

$ Review of the Philosophical Transactions.

IIEHMAPHRODITISM.

729

Professors Osiander* and Feiler,f maintain
with equal inaccuracy that every supposed in-
stance of hermaphroditisra is referable to a
hypospadic state of the penis and scrotum, in
persons that are in other respects essential ly
male.

Various physiologists, again, while they ad-
mit the occurrence of all the different varieties
of spurious hermaphroditism, are inclined to
deny that any such combinations of male and
female organs upon the same body as those
which constitute our several varieties of true
hermaphroditism, are ever observed to occur
in the human subject, or among the higher
classes of animals.], in despite of the recent
accumulation of new and authentic cases, Pro-
fessor M tiller of Berlin is, in particular, in his
excellent treatise on the development of the
genital organs, published in 1830,§ still in-
clined to coincide in a great degree in this
opinion. This distinguished physiologist does
not indeed, as some have done, doubt in any
degree the authenticity of the recorded cases,
and even goes so far as to admit the occasional
occurrence of a combination of male and female
organs upon the same individual, when that
combination does not (as in lateral and trans-
verse hermaphroditism) imply a true sexual
duplicity or repetition of any of the cor-
responding male and female parts ; but he
doubts altogether the probability of our third
division of double or complex hermaphroditism,
and conceives that in the examination of the
cases referable to that section a sufficient degree
of attention has not been directed to the ac-
curate anatomical distinction of the particular
parts supposed to exist, from others with which
it is possible to confound them. We shall
here, therefore, shortly inquire into some of the
principal sources of fallacy which are apt to
mislead the incautious observer in the examina-
tion of such instances as those to which we
allude ; and in doing so we shall consider the
various sources of error in an order conformable
with those divisions of double hermaphroditism
that we have previously adopted, — speaking of
the mistakes which may be committed in judg-
ing of the supposed co-existence, 1st, of a
female uterus, and male vesiculae seminales
and vasa deferentia ; 2d, of a female uterus
and male testicles, &c.; 3d, of both testicles
and ovaries.

1. Fallacies in judging of the addition of
male seminal ducts to a Jemale type of sexual
organs. — That form of sexual duplicity which
we have formerly described as consisting in the
supposed superaddition of male vesiculae semi-
nales and vasa deferentia to an organization in
other respects female, appears to have been

* Neue Denkwuerdigk. fur Geburtshulfe. Bd. i.
n. 8.

t Ueber Angeb. mensliche Misbildung. Land-
shut 1820.

$ Thus Portal, Anat. Med. t. v. p. 474; Haller,
El. Phys. t. viii. p. 7, " merito dubitatur j"
Voigtel, Handbuch der Path. Anat. Bd. iii. s. 364;
Lawrence, Art. Generation, in Rees's Cyclopaedia.

§ Bildunsgescbichte der Geiiitalien.

hitherto observed principally, or indeed only
among the Ruminantia, and has in particular
been repeatedly found in free-martin cows. In
judging of the reality of this variety of herma-
phroditic malformation in any given case, there
is one source of fallacy that requires to be par-
ticularly guarded against, and the consideration
of which may probably go far to explain away
most of the recorded examples of the mal-
formation. In the female sexual parts of some
Ruminantia and Pachydermata,* but particu-
larly in the domestic cow and sow, Dr. Gaert-
ner of Copenhagen pointed out in 1822f the
existence of two canals or ducts which have
since that time been generally described under
his name. On each side of the body, one of
these ducts arises in the vicinity of the ovary,
or near the fimbnated extremity of the Fallopian
tube, runs down first in the duplicature of the
broad ligament, and afterwards in the sub-
stance of the parietes of the uterus and vagina,
to near the meatus urinarius, and there opens
into the vaginal cavity. Each duct communi-
cates with several small glands, follicles, or
cysts that are scattered along its course, and
which perhaps may not be improperly described
as diverticula from the ducts themselves. Now
when we consider the relations of those imper-
fect ducts and cysts that are occasionally ob-
served in the free-martin cow, situated along
each side of the defectively developed uterus,
and which Mr. Hunter has described as male
vasa deferentia and vesiculse seminales, it seems
to us not at all improbable that these supposed
male organs are only in reality the ducts of
Gaertner, with their accompanying follicles or
cysts generally perhaps existing in a morbidly
developed and dilated condition. They seem
at least to correspond much in their origin,
course, and position with the canals and cysts
discovered by Gaertner ; and certainly in the
present state of our knowledge it would appear
more reasonable to refer them to this normal
portion of the female structure, than to regard
them, until we have more decided evidence on
the subject, as abnormal male organs, and as
affording, in consequence, an example of sexual
duplicity.

In the course of the preceding pages we
have had occasion to allude to cases in the
human subject, and in the dog and sheep, in
which vasa deferentia were stated to have
existed in the same individual along with
Fallopian tubes. Whether, in any of these
instances, the supposed male seminal ducts
were merely canals analogous to those described
by Gaertner in the cow and sow, we shall not
take it upon us to determine, but in connection
with this inquiry it is interesting to remark that
Malpighi, who seems to have been well ac-
quainted with the existence of the ducts in the

* M. Delmas seems to have observed a somewhat
similar structure in the Kangaroo. (Ephem. Medic,
de Montpellier, t. v. p 115.)

t Anatomisk Beskrivelse over et ved Nogle Dyr-
Arters uterus undersb'gt Glandulost organ, &c. Co-
penhagen, 1822 ; Edin. Med. and Surg. Journ.
vol. xxi. p. 460.

730

HERMAPHRODITISM.

cow, has suggested that they may also exist in
a more obscurely developed state in the human
female, and may perhaps be identified with the
ramous lacunae described by De Graaf, Bar-
tholin, Riolan, &c.

A. C. Baudelocque has, in a case published
in the Revue Medicale for March 1826,
described a human uterus which contained in
its parietes a canal coming from the right
Fallopian tube, and opening upon the internal
surface of the cervix uteri ; and Moureau and
Gardien seem to have met with a second (?)
similar instance.*

Before leaving this subject of the probable
source of fallacy which we have to guard
against in confounding the ducts of Gaertner
with the male seminal canals, it is necessary
also to observe, that some anatomists f are now
inclined to consider these canals as the perma-
nent remains of the ducts of those Wolffian
bodies which we shall presently have occasion
to allude to more at length, as forming a tem-
porary type of structure in the sexual develop-
ment of the early embryo ; and certainly the
two appear to accord in most points with
respect to their situation and course. If, how-
ever, it happens that further and more accurate
observations prove the two to be different, then
the possible permanent state of the ducts of
the Wolffian bodies must be looked upon as
affording another source of error, by which we
may deceive ourselves in judging of sexual
duplicity from the supposed superaddition of
male seminal canals to a female sexual
apparatus.

2. Fallacies in the supposed co-existence of
a female uterus with testicles and other organs
of a male sexual type. — We have, in a pre-
vious part of this communication, adduced
about twenty different instances in the human
subject, and in the quadruped, in which a
female uterus, or both an uterus and Fallopian
tubes were described as having been found upon
the bodies of individuals that were in other
respects essentially males.

In reference to some of these instances it
has been doubted whether the sexual organiza-
tion of the malformed animal was not entirely
male, the supposed and generally imperfect
uterus being conceived to be formed either by
a morbid dilatation and unfolding of the sub-
stance of the male prostate gland, or by an
abnormal union and development of the vesi-
cular seminales. Thus, in the case detailed by
Ackermann, the only male sexual organ that
was entirely deficient was the prostate, and the
only reputed female organ which was present
was an imperfect cystiform uterus differing
greatly in structure from the form of this organ
in the infant, and having, as in the normal
state of the prostate, the vasa deferentia pene-
trating through its substance without opening
into its cavity, and ultimately terminating along

* Medical Repository for 1826, p. 571.

t As Jacobson of Copenhagen in Journal de
I'lnstitat, t. ii. p. 160; and Die Okenschen Koerper,
&c. Copenhagen, 1830.

with it in the posterior part of the urethra. In
the analogous instance quoted in a preceding
page from Steghlener, a similar arrangement of
parts was observed; and in that case there was,
in the enlarged ureters and renal infundibula,
sufficient evidence (as we shall afterwards point
out when speaking of the probable causes of
hermaphroditism) of a distending power having
acted upon the whole internal surface of the
urinary and genital organs, and with so great a
force (we may in the meantime allow) as to be
capable of producing such a morbid dilatation
and unfolding of the substance of the prostate
as the doctrine alluded to requires. Such an
effect would be the more liable to be produced
if we can suppose this latter organ to have been
disposed, by original tenuity of its coats, or by
morbid softening or other diseased states of its
tissues, to yield more easily to the dilating
power, than any of the other surfaces to which
it happened to be applied. At the same time,
however, we confess that we conceive it unphi-
losophical to endeavour to account for uU the
cases which we have previously quoted of the
addition of a female uterus to a male type of
sexual organization upon this mechanical prin-
ciple, or to attempt to explain away, in the mode
we have just referred to, the evidence which
these cases afford of the occasional occurrence
of this combination as a true form of sexual
duplicity. For even granting that the instances
given by Ackermann and Steghlener, and per-
haps one or two other cases, are not at all
satisfactory in regard to the reputed existence
of such a variety of sexual duplicity, and
allowing, what seems indeed not at all impro-
bable, that the supposed very imperfect uterus
in these examples was merely an organ formed
by a dilatation of the prostate and seminal
ducts, there is still a sufficient abundance of
cases left to which this explanation cannot
possibly apply.

Thus, in the person dissected by Petit, the
imperfect uterus was furnished with two per-
forate Fallopian tubes of three and a half
inches in length, and at the same time it is
distinctly stated that not only the prostate
gland, but the vesiculee seminales and vasa
deferentia were also present. The vasa defe-
ventia, between their origin from the testicles
and their urethral termination, were eacli above
seven inches long, and they entered the urethra
by two apertures that were quite distinct and
separate from the orifice of the uterus, which
opened into the urethral canal at a point placed
between the neck of the bladder and the
prostate. In this case we cannot suppose that
the uterus and Fallopian tubes were formed at
the expense of the prostate gland or male
seminal ducts, as they and all the other male
organs were present ; and consequently we can
only consider the female organs as a super-
addition to, and not a transformation of the
male structures; or, in other words, we must
look upon the above as an instance of duplicity
in a part of the sexual apparatus.

The same reasoning and remarks might be
shewn, if it were necessary, to apply in a greater

HERMAPHRODITISM.

731

or less degree to the other analogous examples
in the human subject given by Harvey and
Professor Mayer,* as well as to the hermaphro-
ditic sheep described by Thomas, and the diffe-
rent cases in the goat mentioned and delineated
by Gurlt and Mayer. In all these latter cases
in the quadruped, the male organization appears
to have been perfectly developed, the testicles,
epididymes, vasa deferentia, and vesiculae semi-
nales being present in all of them; and in
Thomas's sheep the superadded female uterus
shewed internally the usual characteristic rugose
structure, while its cornua terminated in two
long Fallopian tubes. In Gurlt's goat case all
the internal male sexual organs were found,
with the exception of Cowper's glands; and
yet we cannot suppose that these glands could
have been transformed and moulded out into
that distinct and hollow uterus with its two very
long curved cornua, which the reporter has re-
presented as being present; not to mention the
total want of any collateral evidence in this and
in the other cases to which we have just now
referred, of any dilating power having acted
upon the genital or urinary organs in the em-
bryo.

3. Fallacies in the supposed co-existence of
testicles and ovaries. — In several of those in-
stances in which there has been supposed to be
a co-existence of both testicles and ovaries upon
the same side or sides of the body, it seems
highly probable that there has been a fallacy in
the observation, owing to a want of knowledge
of some anatomical circumstances that are liable
to lead us into error in making an examination
of such a case.

We have previously had occasion to allude
to the existence in the foetal state of the Wolffian
bodies, which are placed one along each side
of the spine, and occupy at an early period in
the embryo a great part of the cavity of the
trunk. These bodies, as is now well known
from the investigations of Rathke, Meckel,
Mil Her, Burdach, and others, form in Mam-
malia and Birds at least, and equally so in
both sexes, the primordial matrices of the geni-
tal and urinary organs (see article OVDM), and
in the natural course of development altogether
disappear in man and in the quadruped during
the earlier periods of development, leaving no
vestige of their presence in the extra-uterine
animal.

This particular foetal type of structure, like
every other temporary type of the embryo,
may, from an impediment or arrest in the natu-
ral course of the changes occurring in the deve-
lopment of the body in general, or of the genital
organs in particular, become, we have every
reason to believe, occasionally permanent in
one or more of its parts, and thus by its pre-
sence in the animal lead us to suppose that a
rudimentary testicle exists in an otherwise well-
marked female, or, on the other hand, that an
ovary exists in an otherwise well-marked male.
Both of these mistakes will be the more apt to
be committed if the original excretory duct of

* See his second case in the foetus and those of
the two adults in a preceding page.

the Wolffian body remains, for it may give the
appearance of the addition of a vas deferens to
the supposed testicle, or of a Fallopian tube to
the supposed ovary.

The error, also, of confounding a permanent
Wolffian body with the testicle will be the
more liable to occur, in consequence of the
former body being naturally composed of an
accumulation of convoluted diverticula which
might be readily mistaken by an incautious ob-
server for the seminiferous ducts of the latter.

There is certainly strong cause for doubting
whether, in some of the cases that we have cited
of the supposed co-existence of testicles and
ovaries upon the same sides, the unremoved
Wolffian bodies and their ducts had not either
been mistaken for testicles and vasa deferentia,
while the sexual organization was otherwise
truly female, or for ovaries and Fallopian tubes,
while the type of structure was in other respects
strictly that of the male. This remark may
perhaps with confidence be applied, for ex-
ample, to the case of the free-martin described
by Mr. Hunter ; and in this and in most
other similar instances the supposed testicles
and ovaries have not been at all examined
with any thing like sufficient anatomical ac-
curacy. At the same time, however, it ap-
pears to us impossible to explain away all the
recorded cases of the supposed co-existence of
testicles and ovaries upon this principle. In
reference to this point we would particularly
observe that the consideration of the relative
position occupied by the reputed testicles and
ovaries may perhaps afford us an useful guide
in cases of doubt. In some of the instances
that have been previously cited, the relative
situation of the supposed testicles and ovaries
was exactly such as the Wolffian bodies are
known to bear to these parts. In other in-
stances, however, as in the ape described by
Dr. Harlan, the relative situation in which the
testicles and ovaries were found, was that which
they occupy in the perfectly formed male and
female ; and in such a case as this it would
surely be over-sceptical, and at the same time
in opposition to all that we yet know of the
history of the Wolffian bodies, to suppose that
these bodies had imitated the testicles so far as
to move out of their original locality and travel
downwards through the inguinal rings. At the
same time we must recollect that in this case
the distinctive anatomical structure both of the
testicles and ovaries seems to have been satis-
factorily made out, in so far that the former are
described as " perfectly formed," and the latter
as having " minute ova visible in them." " The
male and female organs of generation," Dr.
Harlan adds, " were as completely perfected as
could have been anticipated in so young an in-
dividual, and resembled those of other indivi-
duals of a similar age." Now if we once admit
in this, or in any one other particular instance,
that the evidence of the co-existence of testicles
and ovaries is satisfactory, then certainly we
may in any equivocal case be entitled to doubt
until we have some more sufficient criterion for
distinction pointed out, whether the dubious
double bodies that we may meet with be a

732

HERMAPHROD1TISM.

rudimentary testicle or ovary conjoined with an
imperfect VVolffian body, or really a true in-
stance of the presence of both testicles and
ovaries upon the body of the same individual.

PHYSIOLOGICAL DEGREE OF SEXUAL PERFEC-
TION IN HERMAPHRODITES.

Among those lower tribes of animals, such as
the Abranchial Annelida, Pteropoda, &c. that
are naturally hermaphrodite, every individual
is in itself a perfect representation of the species
to which it belongs. In the higher orders,
however, in which the distinction and separa-
tion of the sexes comes to be marked, each in-
dividual being either solely male or solely
female, can, as has often been remarked, be re-
garded only as representing one-half of its
entire species. In most instances of hermaph-
roditism among these more perfect animals, the
malformed being does not even attain to this
degree of perfection, but is in general so defec-
tively constituted as not to have the proper
physiological characters and attributes of either
sex. In cases of spurious hermaphroditism it
would appear that sometimes, though the co-
pulative or external sexual parts are greatly and
variously malformed, the internal or proper re-
productive organs are developed with sufficient
perfection to enable them to perform the func-
tions belonging to them. We have very little
proof, however, that in any instances of what
we have described as true hermaphroditism,
the apparatus of either sex is even formed with
such anatomical perfection as to empower the
malformed being to bear a successful part in
the reproductive function. Indeed in all, or in
almost all cases belonging to this last order of
hermaphroditism, the individual who is the
subject of the malformation may, with much
more than poetical truth, be described both
anatomically and physiologically, as, in the
words of Ovid,

Concretus sexu, sed non perfectus utroque,
Ambiguo venere, neutro potiundus amore.

There is on record one remarkable instance
of apparent exception to this general observa-
tion, a notice of which we have reserved for
this place on account of the want of any such
precise knowledge of the true anatomical pecu-
liarities of the case as might enable us to refer
it to the section which it ought to occupy in
our classification. The case to which we
allude was described by Dr. Hendy of New
York, in a letter dated from Lisbon in 1807,
and the subject of it was a Portuguese, twenty-
eight years old, of a tall and slender but mas-
culine figure.* u The penis and testicles," to
adopt the words of Dr. Hendy's own narrative,
" with their common covering the scrotum, are
in the usual situation, of the form and appear-
ance, and very nearly of the size of those of an
adult. The praeputium covers the glans com-
pletely, and admits of being partially retracted.
On the introduction of a probe, the male ure-
thra appeared to be pervious about a third of
its length, beyond which the resistance to its
passage was insuperable by any ordinary justi-

* New York Medital Repository, vol. xii. p. 86.

fiable force. There is a tendency to the growth
of a beard, which is kept short by clipping
with scissors. The female parts do not differ from
those of the more perfect sex, except in the size
ofthelabia, which are not so prominent, and
also that the whole of the external organs ap-
pear to be situated nearer the rectum, and are
not surrounded with the usual quantity of hair.
The thighs do not possess the tapering fulness
common to the exquisitely formed female ; the
ossa ilii are less expanded, and the breasts are
very small. In voice and manners the female
predominates. She menstruates regularly, was
twice pregnant, and miscarried in the third and
fifth months of gestation. During copulation
the penis becomes erect. There has never ex-
isted an inclination for commerce with the
female under any circumstances of excitement
of the venereal passion." In the preceding
case, (if we may confidently trust to the account
given of it,) we have ample proof of the exist-
ence of the internal female sexual organs in the
circumstances of menstruation and impregna-
tion taking place ; and at the same time there
appears considerable evidence for believing
that some of the male organs were present.
For even if we were to argue that the bodies
present in the scrotum or united labia might be
ovaries and not testicles, and that the supposed
semi-perforate penis was only an enlarged cli-
toris, still the masculine figure of the individual,
the imperfect beard, the narrowness of the
pelvis, and the form of the lower extremities
would tend to indicate the probable existence
of the rudiments of some male organs; and if
we go so far as to admit this, we must further
allow the present to be an instance of hermaph-
roditism, in which one of the sets of sexual
organs was capable of assuming their appro-
priate physiological part in the process of' re-
production, though perhaps unable, if we may
judge from abortion having twice occurred, of
ultimately perfecting that process.

The preceding remarks upon the functional
reproductive powers of reputed true hermaph-
rodites have been meant to apply only to the
supposed perfection of one order of their sexual
organs. It becomes a still more interesting
question whether it ever occurs that in any ab-
normal hermaphrodite among the more perfect
tribes of animals, both kinds of sexual parts
may be found in so perfectly developed a state
as to enable the individual to complete the
sexual act within its own body ; or, in other
words, to impregnate and be impregnated by
itself. Though we have assuredly no positive
proof to furnish* that a hermaphrodite so phy-
siologically perfect has ever yet been observed,
and should very strongly doubt its occurrence

* We do not certainly feel entitled to place
among the category of correct observations either
the alleged case given by Linneus (Mangetus' Bib-
liotheca Chirurg. lib. iv. ) of a sow with perfect male
organs on one side, and a womb containing several
fetuses on the opposite ; or that mentioned by
Faber ( Hernandez' Nov. Plant. Anim. Mexic.
Histor. p. 547) and quoted by Haller and Rudolphi,
of the co-existence, in a rat, of ovaries and a uterus
with nine fretuses, along with complete male
organs.

HERMAPHRODITISM.

733

from the almost universal imperfection, in an
anatomical point of view, of the malformed or-
gans, yet we have, on the other hand, no very ra-
tional ground, except that of the experience of
all observers up to the present date, for denying
entirely and unconditionally the utter possibi-
lity of it. And perhaps we should look upon
this possibility with a less degree of scepticism
when we consider that a double hermaphrodi-
tism exists as the normal sexual condition of
some of the lower tribes of animated beings,
and at the same time take into account the fact
of the more or less direct communication which
has been generally found to exist between the
female uterus and the male passages, in cases
of lateral and of complex hermaphroditism in
the human subject and in quadrupeds.

In one of the cases of hermaphroditism in
the goat, previously quoted from Mayer, and
where there were present two male testicles,
epididymes, vasa deferentia, and vesiculae semi-
nales, and a female vagina, uterus and Fallo-
pian tubes, with a body at the abdominal ex-
tremity of one of these tubes that was supposed
by Mayer to resemble a collection of Graafian
vesicles, the male vasa deferentia opened into
the female vagina; and its cavity with that of
the uterus, and of all the male sexual canals,
was distended with a whitish fluid of the odour
and colour of male semen, and containing, ac-
cording to Bergmann, the chemical principle
proper to that secretion. It is not, therefore,
altogether without some appearance of founda-
tion in fact, that Mayer has added to the history
of this case the following problematical remark :
" Fuit ergo revera hermaphroditus semetipsum
foecundare studens."*

In a similar strain Dr. Harlan has added to
the account that he has given of the very com-
plete case of hermaphroditism already men-
tioned as met with in the Borneo ourang-
outang, the following observations and queries.
" Admitting," he remarks, " what in reality
appeared to be the fact, that all the essential
organs of both sexes were present in this indi-
vidual, had the subject lived to adult age, most
interesting results might have been elicited.
Could not the animal have been impregnated
by a male individual, by rupturing the mem-
brane closing the vulva ? or by masturbation,
might not the animal have impregnated itself?
by this means exciting the testicles to discharge
their seminal liquor into its own vagina. The
imperfection of the urethra most probably
would have prevented the animal from ejecting
the semen into the vagina of another indivi-
dual.'^

It has been sometimes urged as an argument
conclusively illustrative of the fact of a double
hermaphrodite impregnating itself, that in the
hermaphrodite Gustrophaga pini described by
Scopoli,J the insect is stated to have been seen
to advance its penis and copulate with its own
female organs ; and afterwards, we are inform-
ed, the female side laid eggs from which young

* Icones, &c. p. 20.

t Medical and Physical Researches, pp. 23, 24.

i lutrod. ad Hist. Nat. p. 416.

caterpillars were produced. Before, however,
admitting this case to present an incontroverti-
ble instance of absolute hermaphroditism, with
the functions of the two sets of sexual organs
existing in a perfect condition upon the same
individual, it is necessary to recollect a possible
source of fallacy in this circumstance, that
female Gastrophagi have been observed to lay
fertile eggs, although they had not had pre-
viously any connection with the male, as re-
marked by Professor Baster* in one instance in
a female Gastrophaga querci/blia, and in ano-
ther in the Gastrophaga pini by Suckow.f The
same fact is further alleged to have been ob-
served in some few instances by Pallas, Trevi-
ranus, Bernouilli, and others,}; in regard to in-
dividuals belonging to some other of the higher
orders of insects and animals, as in the Limnxus
auricularis§ and Helix vivipura\\ among Mol-
lusca, thus bringing them in this respect into
analogy with the Aphides and Cyprides.

CAUSES OF HERMAPHRODITIC MALFORMATION.

As yet we possess very little accurate know-
ledge either in respect to the mode in which
the determining causes of hermaphroditic mal-
formation act, or the nature of these causes
themselves.

Most of the varieties of spurious herma-
phroditism may, as we have just explained,
be traced to an arrest in the development of the
sexual organs at one or other period of their
evolution, in consequence of which some of
those types of structure in these parts which
were intended to be temporary and transitory
only, are rendered fixed or permanent in their
character. Our knowledge of the more imme-
diate causes of such arrested development in
these and in other individual parts and organs
of the body, is as yet extremely limited, and for
the discussion of it we must refer to another
part of the present work, (see article MON-
STROSITIES). We may, however, in reference
to the particular forms of arrested development
observed in hermaphroditism, remark that in
consequence of the great influence which, as
we have already pointed out, is exercised by
morbid states of the ovaries and testicles, in
retarding or preventing the evolution of the
sexual apparatus and characters after birth, it
has been suggested with considerable probabi-
lity by MeckelH and Isidore St. Hilaire,** that
in their ultimate analysis certain cases of her-
maphroditic malformation may be traced in the
course of their causation to morbid influences
exercised in the early embryo, at a period
more or less near to conception, upon the
ovaries or testicles, or upon those organs of a
neuter or yet undetermined sex which after-
wards assume the structure of one or other of

* Mem. de 1'Acad. Roy. de Berlin, 1772.
t Heusinger's Zeitschrift fur Organ. Phys. Bd. ii.
s.263.

$ Burmeister's Entomology, s. 204. Burdach's
siologic, t. i. § 44, 4-8.
Isis for 1817, p. 320.
Spallanzani, Mem. sur la Resp. p. 268.
Anat. Geu. t. i. p. 609.
Hist, des Anomal. de 1'Organiz. t. ii. 58,

734

HERMAPHRODITISM.

these bodies. Further, the effects which this
supposed morbid influence exercises directly
upon the embryonic ovaries and testicles, and
indirectly through them, upon the rest of the
genital apparatus, and consequently the modi-
fications of sexual structure which it produces,
may possibly be much varied according to its
extent, duration, and nature, and according to
the particular period of development at which it
comes into action. It is evident that this ex-
planation of hermaphroditism can only refer
to the varieties of the malformation which
consist of an imperfection or deficiency in the
development, and cannot apply to those in-
stances in which there is a superaddition of
sexual organs. If, however, we can once
satisfy ourselves that any set of cases whatever
are traceable to a morbid action affecting the
testicles or ovaries of the early embryo, our
investigations into the causes of these cases
will necessarily be much simplified, for our
inquiries would be reduced from a vague and
indefinite search after the production of a num-
ber of anomalies of structure affecting several
different organs at the same time, to an attempt
to trace out the nature of those morbid condi-
tions to which the embryonic testicles and
ovaries were subject, and which were capable
of so far changing the structure and action of
these organs as to give rise to the effects in
question. Of the diseased states, however,
to which the reproductive and other organs of
the system are liable during the progress of their
early development, we at present know little or
nothing, although in the investigation of this
subject a key, we believe, may possibly be yet
found to the explanation of many of those
malformations to which different parts of the
body are subject.

Osiander* and Dugesf have suggested
that the variety of spurious hermaphroditism
which consists of a division of the peri-
naeum in the male, may be produced me-
chanically in the embryo by the praeterna-
tural accumulation of fluid in the urinary
canal, on account of an imperforate state of
the urethra, and the consequent distension and
ultimate rupture of the urethra, &c. From
cases published by Sandifort, Howship, Bil-
lard, and many others, we are now fully aware
of the fact that all the urinary canals of the
foetus in utero are occasionally found morbidly
distended with a fluid, which, according to
the interesting observations of Dr. Robert Lee,J
would appear to possess the more character-
istic qualities of urine. We have dissected
one case in which the dilated foetal bladder was
as large as an orange, and have seen in the
Anatomical Museum of Dr. William Hunter
at Glasgow the preparation of another instance
in which the bladder of a full-grown foetus
was dilated to the size of that of the adult
subject. In one case mentioned by Dr. Mer-
riman, the distended organ contained half a

* Neue Deukw. fur Aertzte und Geburtsh, Bd. i.
t. 264, 267.

t Ephem. Med. de Montpellier, t. v. p. 17. 45.
and 52.

t London Med.-Chirurg. Trans, vol. xix.

pint of urine,* and in another detailed by Mr.
Fearn it was capable of containing as much as
two quarts of fluid.f

It is not impossible that the causes in ques-
tion,— namely, the obliteration of the urethra
and the consequent distention of all the urinary
passages, and probably also of the sexual
canals communicating witVi these passages, —
may occasionally produce in the male embryo
a re-opening of the perinseal fissure, giving thus
to the external parts the appearance of a female
vulva, and perhaps at the same time may lead
to the retention and imperfect development
of the testicles by the distention of their ducts,
and the unusual compression to which these
organs may be subjected. Indeed we have
satisfactory evidence, in a few instances, that
such a cause may have been in operation, by
our detecting the other acknowledged effects of
the urinary accumulation in question, — such as
preternaturally dilated ureters, and a cystic
form of the infundibula of the kidneys, as in
a case of hermaphroditism given by Mayer, in
a human foetus,}; in the kid described by
Haller,§ and in the child whose case we have
already quoted from Steghlener. (See trans-
verse hermaphroditism.)

At the same time the total absence of these
collateral proofs in most other cases of hypo-
spadias, our knowledge of the fact that the
perinaeal aperture is in some cases never shut,
and the difficulty of conceiving the possibility
of its being re-opened when once it is firmly
closed, are perhaps sufficient to shew that the
cause or causes alluded to produce in but few
if any instances the effect here attributed to
them.

We deem it not uninteresting to point out
in this place, under the question of the origin of
hermaphroditic malformations, a circumstance
which has struck us in considering one or two
of the cases in which the sexual apparatus of
one side of the body was more imperfectly
developed than that of other, viz. that the
opposite side of the encephalon was at the
same time defectively formed. Thus in the
case of Charles Durge, on the right side of
whose body there was a well-formed testi-
cle, and on the left an imperfect ovary, the
right hemispheres of the cerebrum and cere-
bellum, but particularly of the latter, were
found by Professor Mayer to be smaller and
less developed than the left, and the left side of
the occiput was externally more prominent
than the right. The same author, in the ac-
count of his case of hermaphroditism in a
person of eighteen years of age, which we
have previously quoted,|| and where there was
an imperfect testicle, &c. on the right side, but
no trace of testicle or ovary in the left, inci-
dentally mentions that the right side of the
cranium was somewhat prominent, — " dextra
pars cranii paullulo prominet," in correspon-

* London Med. and Phys. Journ. vol. xxv. p.
279.

f Lancet for 1834-35, p. 178.

$ See p. 8, of Icones, &c.

§ Comment. Soc. Reg. Sc. Getting, torn. i. p. 2.

j| Icones, p. 12.

HERMAPHRODITISM.

735

denc«, there is every reason to believe, with a
slight predominance in size in the hemispheres
of the encephalon of the same side. In ad-
ducing these t\vo cases we do not wish to draw
any inference with regard to the relation of
causation between the size and development of
the encephalic mass and the determination of
the sex, but would merely point out the facts
themselves in the meantime, for the purpose of
drawing attention to the subject in the observa-
tion of any future similar instances that may
happen to occur.

In connection with the question of the causes
of hermaphroditism, it is interesting to remark
that in some instances malformations of the
genital organs giving rise to appearances of her-
maphroditism have been observed both to be
hereditary in particular families, and in other
cases to occur among several of the children of
the same parents. Thus Heuremann* mentions
an example of a family the females of which
had for several generations given birth to males
who were all affected with hypospadias ; and
Lecatf alleges that a degree of hypospadias
is not uncommon among families in Nor-
mandy. In Rust's Magazine an instance is
related of a degree of hypospadias existing in a
father and son.J Baum,§ in his essay on con-
genital fissures of the urethra, has referred to
two instances of the existence of hypospadias
in brothers of the same family, the first men-
tioned by \Valrecht,|| and the second by
GockeMf Sir Everard Home** found two
cases of hypospadias in two children belonging
to the same parents. Kauw Boerhaaveff men-
tions an example of four hypospadiac brothers,
and Lepechin another instance of three.jf
Naegele has reported a case in which two male
twins were both hypospadic,§§ and Katsky ||||
and Saviard^iH have mentioned similar in-
stances.

We have already, when treating of transverse
hermaphroditism, alluded to another fact long
and extensively known among our agriculturists,
but first prominently brought before the notice
of physiologists by Mr. Hunter, that the free-
martin cow, or the cow that is born a co-twin
with a male, is generally barren and has its
sexual organs more or less defectively developed
or hermaphroditically formed.*** In three dif-

* Medicin. Beobacht. Bd. ii. s. 234, and Laroche
sur les Monstrosites de la Face, p. 30.

t Armaud, 1. c. p. 312.

$ Magazin fuer die Gesammte Heilkunde, Bd.
xviii. s. 113.

§ De fissuris urethra virilis fissuris congenitis,
p. 54.

|| Burdach's Metamorphose des Geschlechter, p.
52.

f Eph. Nat. Cur. Dec. ii. Ann. 5. (1686), p. 85.

** Comp. Anat. iii. p. 320.

ft Nov. Com. Acad. Sc. Petropolit. t. i. p. 61.
tab. xi.

J Ibid. t. xv'i. p. 525.

Meckel's Archiv. Bd. v. «. 136.
Acta M. Berol. Dec. 1, torn, ix, p. 61.
f Observ. Chirurg. p. 284.

*** From the Romans employing the female norm
taura to signify a barren cow, it has been ingeni-
ously conjectured that they were not unacquainted
with the free-martin. Thus Columella de Re Rus-

ferent instances Mr. Hunter confirmed the feet
of the anomalous sexual development of such
animals by dissection; and Scarpa* and
Gurltf have published some additional ob-
servations and cases. We have lately had
an opportunity of dissecting the sexual parts of
two adult free-martins, and found them, as
already detailed, formed after an abnormal and
imperfect sexual type ; and our friend Dr.
Allen Thomson made some years ago a similar
observation upon a free-martin twin fetal calf.
Cases, however, exceptional to the general fact
of the sterility and imperfect sexual conforma-
tion of the free-martin twin cow are not unfre-
quently met with. Mr. Hunter found the
sexual organs of a free-martin calf that died
when about a month old apparently naturally
constituted. He speaks also of having heard of
some free-martins that were so perfectly formed
in their sexual parts as to be capable of
breeding ; and different instances of their fe-
cundity have been published by Dr. Moulson
and others J since the time that Mr. Hunter
directed attention to this subject. In some
pretty extensive inquiries which we have made
in regard to this point among the agriculturists
of the Lothians, we have learned only of two
instances in which free-martins proved capable
of propagating, and such cases seem to be
always looked upon as forming exceptions to
the general rule.

We are not aware that among other uni-
parous domestic animals, as the goat, mare,
&c , when a female is born a co-twin with a
male, this female is sterile, and has its sexual
organs hermaphroditically formed, as in the
free-martin cow ; and we are sufficiently as-
sured that no such law holds with regard to
twins of opposite sexes among sheep. Sir
Everard Home, in his essay on monstrous for-
mations, § mentions that in warm countries
nurses and midwives have a prejudice that such
women as have been born twins with males
seldom breed ; and we have found the same
prejudice existing to a considerable degree
among the lower orders in Scotland. Mr.
Cribb,|| of Cambridge, published in 1823 a
short paper in order to refute this notion as far
as regarded the human subject. He refers to
the histories of seven women who had been
born co-twins with males. Six of these had
children, and the remaining seventh subject
alone had been married for several years
without any issue. We have ourselves made
a series of extensive inquiries of the same nature

tica, lib. vi. chap. 22, speaks of " taurae which
occupy the place of fertile cows ;" and Varro in
like manner (lib. ii cap. 5.) states that " the cow
which is barren is called taura" (quae sterilis est,
taura vocatur). There is no evidence, however,
that they were acquainted with the particular cir-
cumstances relative to birth under which free-mar-
tins are produced.

* Mem. della Societa Italiana, t. ii. p. 846.

t Lerbuch der pathol. Anat. Bd. ii. s. 188.

j Loudon's Magazine of Natural History, vol.
v. p. 765. See also Youatt on Cattle, p. 539,
Farmers' Magazine for Nov. 1806 and Nov. 1807.

§ Comp. Anat. vol. iii. p. 333-4.

Jj London Med. Repos. vol. xx. p. 213.

736

HERMAPHRODITISM.

as those published by Mr. Cribb, and have
obtained authentic information regarding forty-
two adult married females who had been born as
twins with males. Of these, thirty-six were
mothers of families, and six had no children,
though all of them had been married for a
number of years. Two of the females who
have families were each born as a triplet with
two males.* In the Medical Repository for
1827 (p. 350) an anonymous author has men-
tioned an instance of quadruplets consisting of
three boys and a girl, who were all reared : the
female afterwards became herself the mother of
triplets. Limited as the data to which we
here allude confessedly are, they are still amply
sufficient to show that in by far the majority of
cases the females of twins of opposite sexes are
in the human subject actually fertile, and, as
some of the cases we have collected show, they
are occasionally unusually prolific.

On the other hand, however, it may be con-
sidered by some that the same data rather tend
in a slight degree, as far as they go, to support
the popular prejudice of the infecundity in a
number of cases of the female twin, and her
analogy in this respect with the free-martin
cow ; for out of the forty-two instances which
we have mentioned, we find six in which the
woman has had no children, though living in
wedlock for a number of years, or one out of
seven of the marriages of such women has
proved an unproductive one, — a proportion,
we believe, considerably above the average
of unproductive marriages in society in general,
or among women of any other class. But
perhaps, before drawing any very decided
conclusion with regard to this point, a more
extended foundation of data would be requisite
than any we have hitherto been able to adduce,
as it is perfectly possible that our having met
with six exceptional cases may be a mere
matter of coincidence.

As to the cause of the malformation and
consequent infecundity of the organs of gene-
ration in the free-martin cow, we will not ven-
ture to offer any conjecture in explanation of it.
It appears to us to be one of the strangest facts
in the whole range of teratological science,
that the twin existence in utero of a male along
with a female should entail upon the latter so
great a degree of malformation in its sexual
organs, and in its sexual organs only. The
circumstance becomes only the more inexpli-
cable when we consider this physiological law
to be confined principally or entirely to the
cow, and certainly not to hold with regard to
sheep, or perhaps any other uniparous animal.

The curiosity of the fact also becomes
heightened and increased when we recollect
that when the cow or any other uniparous ani-
mal has twins both of the same sex, as two
males or two females, these animals are always
both perfectly formed in their sexual organiza-
tion, and both capable of propagating. In the
course of making the preceding inquiries after

* Notes of the histories of these cases individu-
ally were read to a meeting of the Royal Physical
Society of Edinburgh in the beginning of 1837.

females born co-twins with males in the human
subject, we have had a very great number of
cases of purely female and purely male twins
mentioned to us, who had grown up and be-
come married, and in only two or three in-
stances at most have we heard of an unpro-
ductive marriage among such persons.

Further, we may, in conclusion, remark that
among the long list of individual cases of her-
maphroditistn in the human subject that we
have had occasion to cite, we find only one
instance, (Eschricht's case of transverse herma-
phroditism,) in which the malformed being is
stated to have been a twin. Katsky, however,
Naegele, and Saviard have each, as before stated,
mentioned a case in which both twins were
hermaphroditically formed in their sexual organs.

HERMAPHRODITISM IN DOUBLE MONSTERS.

One of the most curious facts in the history
of double monsters is the great rarity of an
opposite or hermaphroditic sexual type in
their two component bodies, the genital organs
of both bodies being almost always either both
female or both male.

Physiological science affords us at present
no satisfactory clue to the explanation of this
singular circumstance. From two cases of
double monstrous embryos observed in the egg
of the domestic fowl by Wolff* and Baer,f
and from a similar case met with in the egg of
the goose by Dr. Allen Thomson, it appears
certain that double monsters sometimes originate
upon a single yolk, probably in consequence of
the existence of two cicatriculae upon this yolk,J
or of two germinal points (or two of the vesi-
cles of Purkinje and Wagner) upon a single
cicatricula. In such a case the two bodies of
the double monster are so early and intimately
united together as to form, almost from the
commencement of development, a single sys-
tem ; and therefore the fact of the uniformity
of their sexual character is the less remarkable.
But in other instances when the double mon-
ster originates (as from the phenomena of in-
cubation in double-yolked eggs we know to be
frequently the case,) on two separate yolks or in
two separate embryos becoming fused or united
together, at a more advanced stage of develop-
ment, it appears more extraordinary that the
sexes of the two conjoined foetuses should be
so constantly uniform as they seem to be in
monsters perfectly double. This uniformity
only becomes the more singular when we re-
flect that twin children are not at all unfrequently
of opposite sexes. §

* Nov. Comment. Acad. Petropolit. tom.xiv. p.
456.

t M eckel's Archiv. fiir Physiologie, &c. for 1827,
p. 576.

\ We have in our possession a preparation, taken
from a duck's egg, in which two full-grown foetuses
are developed on opposite sides of a single yolk of
the common size.

§ In the Edinburgh Lying-in Hospital forty-six
cases of twins occurred from 1823 to 1836, both
years inclusive. In seventeen of these cases the
two children were both females ; in sixteen both
males ; and in the remaining thirteen instances one
child was male and the other female. We know of

IIERMAPIIRODITISM.

737

The fact itself, however we may explain it,
of the comparatively extreme rarity of both
male and female sexual organs upon double
monsters seems sufficiently established by va-
rious careful investigations made into the sub-
ject. Thus out of forty-two perfectly double
monsters which Haller* was able to collect at
the time at which he wrote, there were only
two that were supposed to be of double sex,
or, in other words, that had one body male,
and the other female. Among double-headed
monsters with single lower extremities, he
found an hermaphroditic type more common,
and adduces three examples of it.

In re- investigating this matter, the late Pro-
fessor Meckelf could discover among the nu-
merous class of monsters with perfectly double
bodies united anteriorly or laterally by the tho-
rax and abdomen, only one very doubtful case
of exception to the above general fact. In the
class of double monsters united in the region
of the pelvis he mentions two exceptional
cases from Valentin* and Hasenest;§ of double-
headed monsters with single bodies, he quotes
three similar cases from Lemery,|| Bacher,1[
and Bilsius ;** and of monsters with a single
head and double body he adduces two cases
from Brissaeustt and Condamine,£t in which
in a like manner one body of the monster was
supposed to have female, and the other male
sexual organs. Several of these cases, how-
ever, certainly rest upon too doubtful authority
and insufficient observation.

Isidore St. Hilaire has still further extended
the data on which the above general fact is
founded, by shewing that the same uniformity
of sex holds good with respect to double para-
sitical monsters, §§ and even in monstrosities
double by inclusion. Thus out of this last in-
teresting class of double monsters, he al!udes||||
to ten distinct cases in which the sex of the
included being was ascertained. In six out of
these ten cases the including and included body
were both male; and in the other four they
•were both female.

On the whole, therefore, we must consider
as founded on a proper induction from the ex-
isting data, the axiom of Meckel, — " Sexuum
diversorum indicia in eodem organismo, quan-
tumvis duplicitate peccet, non dari, sed unum
tantum observari."^«[[ But while all the data
hitherto collected with regard to this subject

one family in the different branches of which
twelve pairs of twins have been born within three
generations. In eleven out of these twelve pairs
the co-twins have been of opposite sex.es.

* Opusc. Anat. (1751,) p. 176.

t De Duplicitate Monstrosa, p. 21.

j Eph. Nat. Cur. Dec. ii. Ann. iii. p. 190.

§ Comment. Lit. Norimb. (1743.) p. 58.

f| Mem. de 1'Acad. des Sc. de Paris, for 1724.

^ Roux' Jour, de Med. (1788,) p. 483.

** Blankaari's Coll. Med. &c. (1680.)

it Six Observat. de M. Brisseau, (Paris, 1734,)
p. 33.

$: Mem. de 1'Acad. des Sc.(1733,) p. 401.

\tt Hist, des Anomal. de 1'Oreaniz. torn. iii. pp.
235 and 386.
HI! Ib.p.311.

«"«" De Duplic. Monst. p. 21.
VOL. II.

would seem to point it thus out as one of the
most constant and best ascertained laws in te-
ratology, still we are not altogether disposed to
consider it with Zeviani* and Lesauvagef as
subject to no exceptions whatever. In the
study of monstrosities, as in the study of other
departments of medical science, we find many
general, but no universal laws.

BIBLIOGRAPHY.— Affaitat (J.), De hermaphro-
ditis, Venet. 1549. Columbus, De re anatomica,
lib. xv. Venet. 1559. Bauhin (Caspar), De her-
maphroditorum monstrorumque partium natura.
Francof. 1609. Schenkius (J. G. ), Monstroium
historia memorabilis, Frankf. 1609. Riolan, Dis-
cours sur les hermaphrodites, Paris, 1614. Zac-
chias, Questiones medico-Jegales, lib. vii. Frankf.
1657. Palfyn, Licetus' Traite des monstres. Leid.
1708. Parsons, A mechanical and critical inquiry
into the nature of hermaphrodites, Phil. Trans.
No. xli. and8vo. London,1741. Buryhard, Gruend-
liche Nachrict von cinem Hermaphroditen, Bresl.
1743. Mertrvd, Dissertation sur la fameuse her-
maphrodite, &c. Paris, 1749. Morand, De her-
maphroditis, Paris, 1749. Arnuud, Treatise on
hermaphrodites, London, 1750 ; also in Memoireg
de Chirurgie, torn. i. London and Paris, 1768.
Holler, Commentatio de hermaphroditis, et an
dentur ? in Comment. Societ. Reg. Sc. Gottin-
gensis, torn. i. p. 1-26. Getting. 1752; and Ib.
in his Opera Minora, torn. ii. Lusan. 1764. Can-
tier, Observations sur 1'histoire naturelle, &c.
p. 16, &c. Paris, 1752. Ferrein, Sur le veritable
sexe de ceux qu'on appelle hermaphrodites ; in
Mem. de 1'Acad des Sciences, 1757. Hunter (J.),
Account of a Free-martin, Philos. Trans. 1779;
and Animal Economy, p. 55. London, 1792 ; or in
the recent edition by Owen, 1838. Seiler, Observ.
nonnul. de Testiculorum Descensu et Part. Gecit.
Anomalis, Leipzig, 1787. Osiander, Ueber die
Geschlechtsverwechselungen Neugeborner Kinder,
in his Denkwurdiekeiten f iir Geburtshiilfe, Bd. II.
s. 462. Gotting. 1795, and in the NeueDenkwurdigk,
Bd.I. s. 245. Wrisberg, De Singulari Deformitate
Genitalium in puero Hermaphroditum Mentiente,
Gotting. 1796; and in his Comment. Medici, Phy-
siolog. &c. Argument!. Gotting. 1800, p. 504-551.
Pinel (Ph.), Vices de conformation des parties
genitales, &c. in Mem. de la Soc. Med. d'Emulat.
torn. iv. p. 234. Paris, 1796. lloureau de la Sarthe,
Quelques considerations sur 1'hermaphrodisme,
ibid. torn. i. p. 243 ; also in his Histoire Naturelle
de laFemme, torn. i. p. 211. Paris, 1803. Pietsch,
Gedanken von den Zwittern, in the old Hamburgh
Magazin. Bd. IV. s. 538. Home (Ev.), Dissec-
tion of an hermaphrodite dog, and Obs. on herma-
phrodites in Philos. Trans. 1795 ; On animals
preternaturallv formed, Lect. on Comp. Anat.
vol. iii. London, 1823. Voiytel, Handb. der Pathol.
Anat. Bd. III. Halle, 1805. Ackermann, Infantis
androgyni hist, et iconog. Jena, 1805. Schuberth,
Von Unterschiede der beiden Geschlechter, in his
Allgem. Gesichte des Lebens. Th. I. Leipz. 1806.
Schneider, Der Hermaphroditismus, in Kopp's
Jahrb. der Staatsarzntikunde, p. 193, 1809.
Meckel, Ueber die Zwittrrbildung, in Roil's Archiv
fuer die Physiol. Bd. XI. Halle, 1812; Handb.
der Pathol. Anat. Bd. II. Leipz. 1816; System
der Vergleich. Anatomie, Halle, 1821. Burdach,
Metamorphose der Geschlechter, in Anatona. Un-
tersuchungen, Leipzig, 1814 ; Physiologip, Bd I.
Leipzig, 1826. Metzyer, Syst. der Gericlul. Arz-
neywiss. Konigsb. 1814. Marc, Bulletin des Sc.
Medicalos, torn. viii. p. 179 & 245; Articles on her-
maphrodites in the Diction, des Sciences Medicales,
torn. xxi. p. 36-121, Paris, 1817; and Dirt, de
Medecine, torn. xi. p. 91, Ib. 1824. Steghlener,

* Mem. della Soc. Italian, torn. ix. p. 521.
f Mem. snr les Monstr. par Inclusion (Caen,
1829) ; or Archiv. Gen. de Med. torn. xxv. p. 140.

3 C

738

HERNIA.

De hermaphroditorum Natura, Leipz. et Bamb.
1817. Virey, Article hermaphrodite ou Androgyne,
in Nouveau Diction. d'Histoire Nature-lie, Paris,
1817. Jacoby, De Mammalibus Hermaphroditis
alterno latere in sexum contrarium vergentibus,
Berlin, 1818. Lawrence, Article Generation, in
Rees' Cyclopaedia, vol. xvi. London, 1819. Feiler,
Ueber Angeborne Menschliche Missbildungen, &c.
Landshut, 1820. Picrquin, Cas d'hermaphro-
disme, Montpell. 1823. Henke, Untersuchungen
ueber Hermaphroditen, Gerichtliche Medicin,
Berlin, 1824. Penchienati, Observat. sur quelques
pretendus hermaphrodites, Mem. de 1'Acad. de
Turin, torn. x. Rudolphi, Beschreib. einer selt.
Menschlichen Zwitterbildung, &c. ; Abhand. der
Konigl. Akad. der Wissens. zu Berlin fur 1825.
Ber). 1828. Lippi, Dissert. A natornico-Zootomico-
Fisiologiche, £c. Firenze, 1826. Duges, Mem.
sur 1'hermaphrodisme, in Ephemerides Medicales
de Montpellier, torn. i. Montp. 1827. Kno.r,
Outline of a theory of hermaphrodism, in Brew-
ster's Edinburgh Journal of Science, vol. ii. p. 322.
Edinb. 1830. Muller, Bildungsgeschichte der
Genitalien, Dusseldorf, 1830. Gurlt, Lehrb. der
Patholog. Anat. der Haus-Saugthiere. Bd. II.
Berlin, 1831. Mayer, Icones Selectae praeparat.
Mu-ei Anatom. Bonnensis ; Decas Hermaphrodi-
torum, p. 8. Bonn. 1831 ; and Walther's and
Graefe's Journal, &c. Bd. XVII. Beatty, Article
Doubtful Sex, in Cyclopaedia of Practical Med.
London, 1833. Beck, Medical Jurisprudence,
chap. iv. p. 69-81, Doubtful Sex, London, 1836.
Isidore St. Hilaire, Histoire des Anomalies de
1'organization, &c. Paris, 1836. Barry, On the
Unity ot Structure in the Animal Kingdom, and
in Jarnieson's Edinb. New Philos. Journ. for April,
1837. See also the references in the foot-notes.

(James Y. Simpson.)

HERNIA (in morbid anatomy). The pro-
trusion of any viscus from the cavity in which
it ought naturally to be contained is termed a
hernia, and thus the apparent escape of any
part from any of the great cavities of the body
may seem to constitute the disease : still, how-
ever, as the real existence of cerebral or thoracic
ruptures rests upon very doubtful authority and
is extremely questionable, and as abdominal
protrusions are unfortunately equally palpable
and frequent, the application of the term is
usually limited to them. To this frequency
many causes seem to contribute. In the walls
of the abdomen there are three remarkable
natural openings, or perhaps it would be more
correct to say, there are three situations so weak
and unprotected that they easily yield and per-
mit the escape of any viscus that may be di-
rected against them with even a moderate de-
gree of force : these are, the umbilicus, through
which during foetal life the umbilical cord
passes; the inguinal canal, which allows the
passage of the spermatic cord in the male, and
the round ligament of the uterus in the female ;
and the crural ring, which transmits the great
bloodvessels to the thigh and lower extremity.
The nature of the walls too, which are princi-
pally composed of muscle, and the condition of
the viscera within, loose, liable to change of
size and situation, and subject to irregular pres-
sure by the contractions of these muscular walls,
dispose to the occurrence of the disease in any
of these situations, where the resistance to such
pressure is but feeble. Hence hernise are most
frequently met with at one of the places al-

ready mentioned, — the umbilicus and the ingui-
nal and femoral canals. But there are other
situations* at which protrusions may possibly
take place, although fortunately they are infre-
quent, such as, at the side of the ensiform car-
tilage, at the obturator foramen, at the sacro-
ischiatic notch, and between the vagina and
rectum in the female. It is also evident that
if the muscles or tendons of the diaphragm
are wounded, some portions of the contents of
the abdomen may escape, thus constituting the
varieties of ventral and phrenic hernise. Ac-
cordingly the forms of this disease have been
arranged and named from the different places at
which they occur, — an arrangement of the
greatest practical importance ; for as the struc-
ture, the size, and shape of each aperture must
exert a peculiar influence on the condition of
the protruded viscus, on its liability to become
incarcerated, on the possibility of its being
returned, on the steps to be adopted for this
purpose, and above all on the safety and suc-
cess of an operation should such be necessary,
a knowledge of each of these in connexion with
hernia is absolutely indispensable.

Besides this division of hernia as to situ-
ation, there is another of very considerable im-
portance derived from the nature of the viscus
displaced : thus in abdominal ruptures the con-
tents of the tumour may be intestine alone, in
which case it is called enterocele ; or omentum
alone, the epiplocele ; or both these may be
engaged, constituting the entero-epiplocele.
There is not a viscus in the abdomen or pelvis,
excepting perhaps only the pancreas and kid-
neys, that has not at one time or another
formed the contents of a rupture. The stomach
has been partially displaced through the dia-
phragm, or pushed through the walls of the ab-
domen : the duodenum has formed part of a
ventral or umbilical hernia : the jejunum or
ileum are very likely to be protruded in any
situation: the omentum is often displaced,
particularly in inguinal herniae at the left side :
the large intestines from being more fixed are
not so frequently thrust out, yet the ccecum and
colon are but too often found among the con-
tents of a rupture. 1 have seen a large portion
of the liver in an umbilical hernia of the infant :
Verdierf relates numerous cases of herniae of
the urinary bladder ; and PottJ mentions one
which renders it nearly certain that the ovaria
in females may suffer in a similar manner.
However, the natural situation of any viscus
within the abdomen is but an uncertain cri-
terion by which to judge of the contents of a
hernia in its vicinity. The strangest displace-
ments have been observed occasionally in the
examination of this disease : thus the sigmoid
flexure of the colon has been protruded at the
right side, and the coecum and valve of the ileum
at the left. In all large and old herniae the
parts are dragged out of their proper situations,

* Sur plusieurs hernies singulieres. Garengeot,
Memoires de 1'Academie Royale de Chir. torn. iii.
p. 336. Paris edit, in 15 vols. 1771.

t Mem. de PAcad. Royale de Chir. torn. iv.p. 1.

t Pott's Works, by Eaile, vol. ii. p. 210.

HERNIA.

739

and their appearances on dissection and rela-
tive positions are often such as no one from
anatomical knowledge alone could ever have
suspected to be possible.

In all forms of abdominal hernia excepting
those only which immediately supervene on
penetrating wounds, the contents of the rupture
are lodged within a pouch or bag termed the
hernial sac, which is formed of the peritoneum.
This membrane lines the entire cavity so per-
fectly and completely that nothing can pass out
from it without the membrane also participating
in the derangement and being pushed out before
the displaced viscus. Once formed, this sac
is rarely capable of being replaced or returned
into the cavity of the abdomen ; never unless
the hernia is small and recent, and " the cel-
lular substance accompanying it and the sper-
matic cord through the ring has not lost its
natural elasticity and contractility." * Many
surgeons have doubted the possibility of such
an occurrence at any period, f but the fact has
been demonstrated by dissection, and still more
forcibly by the circumstance of the hernia
having been thus strangulated within the ab-
domen when the sac has been returned along
with it. However, as I have said, the sac when
once formed is rarely capable of being replaced,
nor does it long remain in this abnormal situation
without undergoing some change in its patho-
logical condition — a change which it is not
always easy satisfactorily to explain. In small
herniae that have recently come down, the struc-
ture of the sac differs in nothing from that of
the abdominal peritoneum ; and if the rupture
is not reduced or kept up by a truss, it will pro-
bably increase in size without any remarkable
alteration of tissue, for the membrane is ex-
tremely distensible, and will accommodate
itself to any quantity of contents. But, if the
hernia is carefully kept up, there can be no
doubt that the sac will gradually contract and
seem to rise up and approach the opening
through which it originally passed, so that,
although its cavity is never completely oblite-
rated, it is palpably diminished in size, and in-
capable of receiving and retaining the same
quantity of contents it originally held. Some-
times in old and neglected herniae the sac
seems to become so thin that the peristaltic
motion of the intestines within it has been
clearly perceived : this most frequently occurs
in umbilical hernia, and is one of the reasons
why this form of rupture was supposed not to
have been enveloped in a sac at all. Again, on
the contrary, in old herniae also, and particularly
where bandages have been worn to support or
compress the tumour, it seems to become very
thick, strong, and tense, and is said to have Veen
met with as tough and as thick as cartilage.
But in the great majority of instances these
changes are rather apparent than real, and
though doubtlrss the structure of the sac is no
longer exactly that which it possessed before
protrusion, the alteration is not so great as

* Scarpa on Hernia, translated byWishart, p. 68.
t See Louis, Mem. de 1'Acad. Roy. de Chir.
torn. ii. p. 486.

some writers have supposed. It was the
opinion of Scarpa that an old hernial sac is in
reality but slightly if at all thickened, and that
the apparent thickening is caused by the con-
densation of the cellular tissue external to and
around it. And here I may remark that diffe-
rences of opinion as to the altered structure of
the sac may have arisen from a difference of
accuracy and minuteness in examination, either
during the progress of an operation or after
death. We shall find hereafter that the normal
anatomy of the parts connected with hernia is
largely indebted to the knife of the anatomist
for the shapes of the different openings, the
division and enumeration of the different layers
of fascia, and many other points; but in the
morbid anatomy of the disease the same patient
investigation and the same accuracy of descrip-
tion has not been so uniformly observed, and
hence our knowledge of the latter part of the
subject as compared with the former is by no
means so defined and exact.

Where a rupture has been a long time down,
it is not probable that the intestine shall thus
remain in an abnormal situation without occa-
sionally suffering from inflammation, and hence
adhesions between it and the sac are by no
means unfrequently formed : the same effect
may be produced^ by accidental violence, or
from the latter cause the sac may be ruptured
and its contents left lying under the usual
coverings independent of the peritoneum.
This is another of the cases in which a hernia
has been supposed to exist without the invest-
ment of a sac.

The peritoneal aperture leading from the
cavity of the abdomen into that of the rupture
is narrow, and is called the neck of the sac : its
dimensions as to length, however, vary with
circumstances. As long as the communication
is open and free between the two cavities, all
that portion of peritoneum which is placed
between them and corresponds to the canal
through which the rupture has passed, may be
termed the neck, and thus in inguinal hernia
may be an inch, and in crural half an inch in
length. But when the protruded parts are
strangulated, the little circle only around which
the compression directly operates is more pro-
perly entitled to the appellation, and its extent
is seldom greater than two lines. When the
neck of the sac of a very recent hernia is viewed
from the cavity of the abdomen, the peritoneum
in its vicinity is seen thrown into slight folds or
plaits, which appear to be prolonged down wards
into the tumour; but on slitting open the neck,
I have never seen this appearance within it, the
membrane there being smooth, rather whiter and
more opaque, and evidently thicker and more
unyielding than elsewhere. If such a hernia
in the living subject has been reduced and kept
up by a truss, the nock gradually contracts
under the pressure, an.!, iis diameter with re-
spect to that of the ring tnrough which it has
passed is altered to a degree that is of the
greatest importance in the event of another pro-
trusion, for it will be shewn hereafter that such
a diminution of size greatly predisposes to the
occurrence of strangulation. It is also possible

3c 2

740

HERNIA.

that the neck shall be so contracted that in the
new occurrence of hernia an additional portion
of peritoneum may be detruded, and then the
sac must present the shape of an hour-glass,
narrow in the centre and broad at either end :
sometimes two, three, or more of these succes-
sive protrusions take place, and then the sac
is divided into so many sacculi with incomplete
intercepts or partitions between them. Or one
portion of peritoneum may be forced within
another, so that the intestine is actually in-
cluded within a double sac. This last is a
curious and very uncommon occurrence. On
the other hand the neck of a hernial sac may
suffer distension. In very old ruptures that
have become irreducible or from any other
cause been long down, the neck of the sac
sometimes becomes wonderfully dilated, and the
portion of intestine immediately passing through
it scarcely subjected to the slightest pressure.

There is one form of hernia, the chief
peculiarity of which lies in the nature of its
peritoneal investment, for, correctly speaking, it
possesses no proper sac. It is the hernia con-
genita,* a species of rupture which occurs in
very young infants, and sometimes, under
peculiar circumstances, in persons of a more
advanced age also.

During the early periods of foetal existence
the testes do not occupy that situation which
they possess in after life. They are placed
within the abdomen, above the pelvis, which at
this time is so small and imperfectly developed
that many of the viscera lodged within it after-
wards, seem now to lie within the belly. They
are just below the kidneys, in front of the psoas
muscle at each side, and possess, like other
viscera, an investiture of peritoneum, which is
afterwards to be the tunica vaginalis testis.
About the sixth month, or perhaps the seventh
or even later, (for it observes no exact rule in
this respect,) the testis begins to descend, not
gliding behind the peritoneum, but preserving its
own investing coat until it comes to the internal
abdominal ring, where it pushes a process of
peritoneum out before it, just as an intestine
would do in the production of a hernial sac.
This is afterwards to become the tunica vaginalis
scroti. The testicle then passes on through the
inguinal canal, through the external ring,f and
fit-ally drops into the scrotum. After some
time the canal of communication with the cavity
of the abdomen begins to contract and close,
and if the usual process goes on healthily and
without interruption, very shortly a complete
obliteration takes place, and the testis is sepa-
rated from the abdomen perfectly and for ever.
The time at which this is accomplished is ex-
tremely uncertain : sometimes it is perfect at
birth ; in other cases the canal is more or less
open, and then, if the infant cries or struggles,
a portion of the contents of the abdomen is
protruded into the cavity of the tunica vaginalis,

* Hunter's Animal (Economy.

t See some observations on the descent of the
testicle by the late Professor Todd, of Dublin, in the
1st vol. Dublin Hospital Reports. See also Key's
Observations in Surgery, p. 226.

and the hernia congenita is formed. If any part
of the above-mentioned process is interrupted
or postponed, it will occasion some variety.
Thus the tunica vaginalis may not exhibit its
usual disposition to close and become obliter-
ated at its neck, and then for a length of time
the patient is exposed to all the inconvenience
and hazard of the descent of a hernia: sometimes
the testicle does not come down until a much
later period, a circumstance that is often occa-
sioned by the gland contracting adhesions with
some adjacent viscus in its passage, and may be
attended with the additional inconvenience of
drawing down such viscus along with it. The
surgeon should also be aware of the possibility
of the protrusion of another portion of perito-
neum into the open tunica vaginalis, and thus a
mixed case may arise of a congenital containing
within it a proper sacculated hernia.

The congenital rupture, then, has no proper
sac, but is lodged within the tunica vaginalis in
close apposition with the testis r hence many
of its peculiarities can be explained. It is
obviously the only kind of hernia in which an
adhesion can exist between the testicle and the
protruded viscus, and it is also evident that the
testis does not bear the same relation to the
protruded viscus in this that it does in cases of
ordinary rupture. Here it is higher up, and
seems to be more mixed and identified with the
other contents; the entire tumour is more even
and firm, the protruded parts are less easily
felt and distinguished; and Hesselbach states
that when strangulation is present, the sac is
every where equally tense, and the testis cannot
be felt at all. In very young infants a small
quantity of fluid is often present along with the
intestine in the tunica vaginalis : it disappears
when the child is placed in the recumbent posi-
tion, and does not add to the difficulty or im-
portance of the case. It has been stated that
the tunica vaginalis has a natural tendency to
become closed at its neck, and therefore is it
more likely to thicken and diminish in capacity
in this situation so as to form a band round the
protruded viscus. Pott* was of opinion that
congenital hernia was more subject to be con-
stricted at the neck of the sac than any other :
Wilmer stated that out of five cases of congen-
ital hernia on which he operated, three were
strangulated at the neck of the sac; and Saudi-
fort and others maintained the same doctrine.
Scarpaf thought that every displaced portion
of peritoneum possessed the same tendency to
contraction, and advanced it as a reason why
stricture in the neck of a hernial sac should be
more frequent in all kinds of hernia than is
generally supposed. It is not easy to place
implicit reliance on this latter opinion, because
the neck of the common hernial sac when once
formed is never again completely closed ; but
with respect to congenital hernia the observa-
tion appears to be equally correct and im-
portant.

ScarpaJ describes a form of hernia which may

* Pott, op. citat. p. 184.

t Page 131.

$ Op. citat. p. 205 et seq.

HERNIA.

741

under certain circumstances of imperfect or care-
less examination appear to be devoid of a proper
sac, formed by a descent of the peritoneum.
This occurs at the right groin, is always large,
and is formed by a protrusion of the co2cum
with the appendix vermiformis and the begin-
ning of the colon. The co2cum is placed in the
right ileo-lumbar region, and a portion of it does
not possess a peritoneal covering, but lies abso-
lutely without the great abdominal membranous
sac : when therefore these parts are protruded,
a portion of the coecum and the beginning of
the colon will be found included and contained
in the hernial sac, while another portion of the
same intestines will be necessarily without the
sac, and lying denuded in the cellular substance
which accompanies the descent of the perito-
neum in the hernia. If this tumour is opened
into by an incision carried too much towards
its external side, the coecum and colon will be
exposed lying outside of the peritoneum, and ap-
parently devoid of a hernial sac ; but if cut
into precisely in the middle or a little towards
the inner side, under the cremaster muscle and
the subjacent cellular tissue, the true hernial
sac will be found, formed of the peritoneum.
Within this will be seen " the greater portion
oftheccecum with the appendix vermiformis,
and likewise the membranous folds and bridles
which seem to be detached from the hernial
sac to be inserted into these intestines, the
smaller portion of which will be without the
sac, in the same manner as when these viscera
occupied the ileo-lumbar region." This form
of rupture I have never seen, and must there-
fore refer the reader to Scarpa's work, wherein
he will find the peculiarity most satisfactorily
explained.

But in the arrangement of herniae, that di-
vision is most practically interesting which has
reference to the condition or state of the intes-
tine or other protruded viscus, and the disease
is then described as being reducible, or irredu-
cible, or strangulated.

1. A hernia is said to be reducible when it
either retires spontaneously on the patient as-
suming the recumbent posture, or can be re-
placed without difficulty to the operator or
future inconvenience to the patient beyond that
resulting from the employment of measures
adapted to retain it within the cavity. This
condition supposes that the relation (particu-
larly as to size) between the hernia and the
aperture through which it had escaped has not
undergone any alteration.

2. It is irreducible when there is such a
change in the structure, situation, or other con-
dition of the protruded viscus as to render it
impossible to be returned, although the aper-
ture through which it passed may offer no im-
pediment. There is another case in which a
hernia has been considered irreducible, namely,
when it would be impolitic or unwise to attempt
the reduction, supposing it to be perfectly
practicable.

3. A hernia is strangulated when the relation
as to size between the protruded viscus and the
aperture through which it has passed is so
altered as not only to prevent reduction, but

to cause such a degree of compression at
the aperture as will interrupt the circulation
through the escaped viscus, and endanger its
vitality. This condition has been supposed to
exist in two different forms, strangulation by
inflammation and by " engouement,"* or as
Scarpa terms them, " the acute and chronic ;"f
but this division only has reference to the
severity of the symptoms and to the rapidity
or slowness of their progress, for although an
intestine may be in a stale of obstruction which
will, if unrelieved, proceed to strangulation, yet
the latter state cannot be said to have arrived
until the return of the venous blood from it is
actually impeded. The protruded viscus is
then in a situation precisely similar to that of a
limb round which a cord had been tied with
sufficient tightness to interrupt the circulation
and threaten to induce mortification.

These different conditions will be best under-
stood by tracing a rupture through each of them
in succession.

A person may be suspected to have a reduci-
ble hernia when, after the application of some
force calculated violently to compress all the
viscera of the abdomen, an indolent turnout-
appears proceeding from some of those places
where the walls of the abdomen are known to
be weakest and least resisting. And the sus-
picion is increased if the tumour is elastic, if
it sounds clearly on gentle percussion, and
becomes suddenly puffed up and swelled, as if
by air blown into it, when the patient coughs,
sneezes, or performs any of those actions which
forcibly agitate the abdominal parietes. The
reducible hernia becomes smaller or perhaps
disappears altogether when the patient lies
down : it appears of its full size when he stands
erect ; if neglected, it has a constant tendency
to increase, which it does sometimes by de-
grees, slowly and almost imperceptibly, but
more frequently by sudden additions to its
bulk, which are formed by new protrusions.
In this form of the disease the qualities of the
viscus engaged within the sac, as to form, size,
and structure, may be considered as unchanged :
within the abdomen, however, the fold of
mesentery which supports the protruded intes-
tine is constantly more elongated than it natu-
rally should be, and likewise thicker and more
loaded with fat. It is also marked with dilated
and tortuous veins.

Although thus displaced, the viscus is still
capable of performing its part in the function
of digestion, and as long as the contents of the
bowel pass fairly and uninterruptedly through
it, there can be little or no danger ; but it is
not difficult to conceive how a gut so circum-
stanced may occasion great inconvenience.
The peristaltic motion must be more or less
impaired ; the passage of the contents may be
delayed, and hence will arise nausea, colicky
pains, eructations, and those other dyspeptic
symptoms from which even the most favoured
patients do not escape. These irregularities

* Goursaud, Mem. del'Acad. Roy. de Chir. torn,
ii. p. 382.

t Op. cit. p. 290.

742

HERNIA.

again can scarcely exist for any length of time
without producing some inflammation, and
thence it follows that it is rare to meet with an
old hernia in which adhesions have not formed
either between the intestine and the sac, or
between the convolutions of the protruded
viscera, circumstances that must render it im-
possible to replace the hernia, or supposing it
replaced by force, will be likely to occasion
incarcerations within the cavity of the abdomen
itself. These adhesions, as discovered either
during operation, or by dissection after death,
are of different degrees of closeness, firmness,
and tenacity, and have been arranged under
three classes, the gelatinous, the membranous,
and the fleshy.

"The gelatinous adhesion, a very general
consequence of the adhesive inflammation
which attacks membranous parts placed in
mutual contact, is only formed by a certain
quantity of coagulable lymph, effused from the
surface of the inflamed parts, which coagulating
assumes sometimes the appearance of a vesi-
cular reddish substance stained with blood,
sometimes of threads or whitish membranes
easily separable from the parts between which
they are interposed and which they unite to-
gether, without any abrasion or laceration being
produced by the separation, on the surface of
the parts agglutinated together."* This kind
of adhesion being the result of recent inflam-
mation can rarely be met with in operations
performed for the relief of strangulated hernia,
for the condition of a viscus so engaged is that
in which such an effusion would be unlikely, if
not impossible. Its vessels are loaded and
congested with venous blood : there is effusion
of serum to a greater or less quantity, as is seen
in every instance of obstructed venous circu-
lation ; and if there is recent lymph, it must be
owing to the fortuitous circumstance of the
viscus having been inflamed immediately before
it became strangulated. In a vast number of
cases operated on, I have seen but one instance
of the existence of this soft adhesion, and in that
the hernia was not strangulated : it was a case
(such as is related by Pott) of inflammation
affecting the intestines generally, in which those
within the hernial sac, of course, participated.

The membranous and fleshy adhesions are
the results of former attacks of inflammation,
and are exactly similar to those attachments so
frequently met with between serous surfaces in
other situations. When the opposed surfaces
lie motionless and undisturbed, their connexion
is firm and fleshy, and hence this kind of adhe-
sion is seen at the neck of the sac, between the
omentum and the sac, and occasionally between
the intestine and the testicle in congenital
hernia ; whilst between the convolutions of the
intestine itself, or between it and the sac, any
union that exists is more generally loose and
membranous.

Besides adhesion, there are many other
causes that may render a hernia irreducible,
one of the most prominent of which is the
patient's neglect in leaving the hernia down,

* Scarpa, p. 180.

and the alterations in shape and structure that
thence ensue. In such case, the parts within
the tumour, as the mesentery and omentum,
have room to increase, whilst at the mouth of
the sac they remain constricted and of their
natural size, though condensed and solidified in
structure. This happens particularly with the
omentum, which becomes hard, very dense, and
compact, and not unfrequently resembles a
fibrous structure covered by a fine smooth
membrane, and then there is within the sac a
tumour actually much larger than the aperture
it would have to pass, and through which no
force could be capable of pushing it.

It may happen that the part of the omentum
which is below the stricture shall remain loose
and expanded, and enjoy its natural structure,
whilst that which is lodged within the neck of
the sac is compressed and hardened, in which
case the hernia will probably prove irreducible.
It sometimes happens that scirrhus of the
intestine renders a hernia irreducible. Such a
malignant alteration of structure is by no means
frequent in the intestinal tube — certainly far
less so than in the omentum, but the possibility
of the occurrence is proved by a case under rny
own immediate superintendence. The patient
had a large hernia which he had been able
occasionally to reduce, but which was usually
left down. On a sudden he was attacked with
symptoms of strangulation, small quick pulse,
tenderness of the abdomen, acute pain in the
tumour, constipation, general low fever and
fcecal vomiting. The operation was performed,
and the cause of the symptoms found not to
have been in the situation of the neck of the
sac, which was more than commonly open and
free, but in a scirrhus of one of the lesser
intestines.*

The form of hernia already noticed as being
apparently devoid of a sac has been mentioned
by Pottf as one peculiarly difficult of reduc-
tion. " They have consisted of the coecum with
its appendicula and a portion of the colon.
Nor," continues this distinguished surgeon," will
the size, disposition, and irregular figure of this
part of the intestinal canal appear upon due
consideration a very improbable cause of the
difficulty or impossibility of reduction by the
hand only."

The last circumstance to be considered as
rendering a rupture irreducible is the absolute
size of the tumour and the quantity of viscera
it contains. It is amazing to what extent the
contents of the abdomen may be protruded
from it, and the patient nevertheless enjoy a
state of health that might be called good, so far
as the annoyance of such a tumour could
warrant the expression. Every surgeon must
have heard of hernise in which all the loose
intestines were protruded, and in fact every
thing that could with any degree of probability
be supposed to have been capable of being
pushed from the cavity of the abdomen. I

* The preparation of this interesting case is in
the Museum of the Medico-Chirurgical School, Park
Street, Dublin.

t Pott, op. cit. p. 24.

HERNIA.

743

have seen and dissected a case of this descrip-
tion in which the tumour during life reached to
within two inches of the knee, and obliged the
unfortunate subject of it (who was a lamp-
lighter) to wear a petticoat instead of breeches.
Similar instances are not very unfreqnent, and
it is obvious that an attempt at reduction here
would be injudicious even if it was practicable.
It is the nature of all hollow structures in the
body, whether cavities or vessels, to accommo-
date their size and capacity to the quantity of
their contents, and the cavity of the abdomen
will, under such circumstances, become so con-
tracted as to be either incapable of immediately
receiving the protruded viscera again, or else
the sudden distension will excite peritoneal
inflammation — an evil greater than the existence
of the hernia. These latter, however, cannot
be regarded as permanently irreducible, for
Arnaud, Le Dran, and Hey have succeeded
in gradually restoring them by means of a
bandage shaped like a bag, which being laced
in front admitted of being tightened still as the
tumour diminished.

The last and most fearful condition of a rup-
ture is its state of strangulation, in which the
protruded viscus, no longer capable of being
returned to its former situation within the ab-
domen, no longer fit for the performance of its
functions, is banded and bound down at its
neck in such wise as to interrupt and impair
the circulation through it. In order properly
to understand this part of the subject, it will be
necessary to consider it under three heads : —
1. the causes that seem to produce the stran-
gulation ; 2. its effect on the structures within
the hernial sac ; 3. its effect on the viscera
within the cavity of the abdomen.

1. Of the three natural apertures at which
abdominal herniae commonly occur, one, the
umbilicus, is unquestionably seated within
tendon, and so circumstanced that any con-
traction of any muscle connected with it, whe-
ther spasmodic or permanent, must rather ex-
pand the opening than contract it. Another,
the crural ring or canal, is composed of tendon
and of bone, and so constructed that although
certain positions of the trunk or inferior extre-
mity might possibly diminish its size, no mus-
cular action can exert any influence over it.
The third, the inguinal canal, is of greater length
and more complicated in its construction, and
it is a question whether the same pathological
condition can be predicated of it, or whether
strangulation does not here occasionally occur
in consequence of muscular action alone.* Sir
A. Cooper seems to acknowledge the possibility
of a spasmodic stricture at the internal ring, the
strangulation then being effected by a com-
pression exercised by the inferior edge of the
internal oblique and transversalis muscles.f
Guthrie speaks of herniae being frequently
strangulated by passing between the fibres of
the internal oblique, which are separated at the
inferior and external border of the muscle above

* See the anatomy of inguinal and femoral hernia
in a future part of this article.
t Cooler on Hernia, p. 21.

the origin of the cremaster.* Scarpa says that
" towards the side, at about eight lines distance
from the apex of the ring, the lower muscular
fibres of the internal oblique muscle separate
from each other to allow the spermatic cord to
pass between them :"f and again, " the small
sac or rudiment of the hernia, not unlike a
thimble, when it makes its first appearance
under the fleshy margin of the transverse, rests
immediately on the anterior surface of the
spermatic cord ; it then extends and passes in
the middle of the separation formed by the
divarication of the inferior fleshy fibres of the
internal oblique and of the principal origin of
the cremaster muscle."]; It must, however, be
conceded that Scarpa did not attribute the
strangulation of any form of inguinal hernia to
a contraction of these muscular fibres. Now,
although it is almost presumptuous to differ
from authorities of so high a class, yet I cannot
agree either with the opinion that herniae are
liable to a spasmodic constriction, or with the
descriptive anatomy on which such an opinion
might be founded.

In about one subject out of every three or
four there certainly is a slight divarication or
separation of fibres of the external oblique
muscle, or rather there is a cellular connexion
between the origin of the cremaster muscle and
the inferior fibres of the oblique, which is easily
separable by the knife ; but the question is,
does the spermatic cord in the natural condition,
or the hernia in its course to the external ring,
pass through or between these fibres ? I believe
they do not. I have dissected numerous cases
of hernia without observing such a disposition
of parts, and I think that if either the spermatic
cord or the hernia took such a course, the pro-
trusion must then come to lie in front of the
cremaster muscle — a position that has not been
hitherto observed. When a hernia is found at
the groin, the tendon of the external oblique is
somewhat stretched and arched forwards above
Poupart's ligament in front of the inguinal
canal : the fascia transversalis may be stretched
also, and the epigastric artery pulled out of its
place and made to approach the linea alba;
but the muscles arising from Poupart's liga-
ment, the internal oblique and transversalis, re-
main unchanged, and if ever strangulation is
effected through their operation it is in the
manner suggested by Sir A. Cooper. But it
is more simple and perhaps more scientific to
place muscular contraction out of the question
altogether. The phenomena of strangulation
exhibit nothing like the irregularities of spasm:
there is no sudden exacerbation, no succeeding
relaxation — no alternation of suffering and re-
lief, no assuagement of symptom from medi-
cines decidedly antispasmodic; the disease once
established goes on with an uninterrupted and
certain progression that will not admit of expla-
nation by a cause so irregular as spasm.

But it is unnecessary to resort to an expla-
nation which might prove so practically dan-

* Guthrie.

t Scarpa, op. cit. p. 27.

J Ibid. p. 50.

744

HERNIA.

gerous, because the existence of strangulation
with all its fearful sequelae may be proved, in
situations and under circumstances where the
influence of spasm or of muscular action is ob-
viously impossible. Thus intestines have been
found strangulated within the cavity of the ab-
domen itself, as when a fold of intestine has
passed through an accidental opening in the
mesentery or the omentum, or when artificial
bands or nooses have been formed by lymph,
the products of former inflammation. Scarpa
relates a very interesting case in which he
found that the appendix vermiformis surrounded
in the manner of a ring and strangulated a long
loop of the ileum just before its insertion into
the colon.

If it be conceded that the natural openings
at which abdominal herniae occur are composed
either of tendon or of tendon and of bone, and
therefore are not subject to accidental variations
of size from irregular muscular action, it would
seem on a prim a facie view that wherever any
substance had passed out it ought to be able
to return, provided an equal degree of force is
employed with that which originally caused
the displacement. And this actually does take
place, for the hernia returns spontaneously or
is easily reduced as long as the original propor-
tion between the size of the protruded part and
that of the aperture remains unaltered. Again,
as long as this relation is maintained, the cir-
culation through and from the protruded viscus
will continue equable and healthy, but an in-
testine from its structure and its functions is
extremely liable to a change of size, and when
that happens, the proportion no longer exists,
and the hernia begins to become incarcerated.
If not relieved, the protruded viscus continues
to swell, and is thus made to form an acute
angle at the spot where it escaped, which
tightens the ring of intestine immediately at
the neck of the sac : the return of the venous
blood is thus prevented; the swelling then
increases until not even gas can pass through,
and then strangulation is complete. In this
way a number of circumstances connected with
hernia can be explained. If the ring is small,
a very trifling change of size in the protruded
part will be sufficient to cause strangulation :
hence crural hernia is more liable than inguinal,
and very recent ruptures in which the ring is of
its natural size than those of long standing, in
which that aperture is probably enlarged.
Persons who are formed with large rings, and
thus possess an hereditary disposition to hernia,
are less liable to strangulation : this may ex-
plain Pott's remark that " if the hernia be of
the intestinal kind merely, and the portion of
the gut be small, the risk is the greater, stran-
gulation being more likely to happen in this
case ;" for assuredly if the ring is so small as to
]>ermit only the escape of a knuckle of intestine,
a very trifling change in the latter will be suffi-
cient to establish a disproportion between
them. Again, if a hernia has come down, and
been reduced, and kept up until the neck of
the sac has been diminished in size, and if
afterwards a protrusion takes place, a very
trifling alteration in this latter will render it

incapable of return, and explain why such her-
niae are so frequently strangulated at the neck
of the sac. Hence it appears that a straitness
or tightness at one of the rings may be a predis-
posing cause of strangulation, that is, may be
a reason why one hernia should become sooner
strangulated than another, but the immediate
or efficient cause is a change in the condition
of the viscus itself. Thus when a loop of in-
testine is gangrened, and its contents have
escaped totally or partially into the sac, the
hernia often returns spontaneously, the parts in
the immediate neighbourhood of the ring re-
maining unaltered. Also if such a hernia is
the subject of operation, there is no necessity
for dilating the seat of the stricture : indeed
Louis forbids the practice lest some essential
point of adhesion should be destroyed. " Di-
latation," says he, " is only recommended in
order to facilitate the reduction of the strictured
parts. In the gangrened intestine there is no
reduction to make, and there is no longer
strangulation, the opening in the intestines
having removed the disproportion that had
existed between the diameter of the ring and
the volume which the parts had acquired; and
the free passage of the excrement which the
sphacelus has permitted removes every symptom
that depends on the strangulation."* In like
manner may be understood why omental her-
niae are less liable to become strangulated, be-
cause this structure is not subject to any sud-
den change of shape or increase of volume :
when it does occur, the progress of the disease
is more slow, and the symptoms are said to be
less severe.

The division of herniae into the incarcerated
and strangulated, or into the acute and chronic
forms of strangulation, however practically
valuable if it inculcates a different mode of
treatment for these affections, is yet pathologi-
cally incorrect if it supposes any analogy be-
tween them and the acute and chronic species
of inflammation. An incarcerated hernia is
not strangulated ; it is really in a condition re-
sembling irreducibility. I have before stated
that in large and old hernias the neck of the sac
generally becomes enlarged, and of course such
a change of dimensions in the protruded viscera
as is necessary to cause their strangulation will
be proportionally less likely to occur. But
hard and unwholesome and indigestible sub-
stances may gain admission into some of them
and lodge there, for it must be recollected that
the process of digestion cannot be very favora-
bly carried on in intestines thus protruded,
placed in positions that will render it necessary
that their contents must ascend against the in-
fluence of their own gravity, and deprived of
the salutary pressure exercised by the walls of
the abdomen on the viscera within it. If such
a lodgment is formed, it will be the cause of
future accumulation, and may occasion a deter-
mination of blood to the part or even inflam-
mation within it, thus gradually increasing its
volume and leading it to a state that must end
in strangulation. Undoubtedly, if the dura-

* Mem. de 1'Acad. Roy. de Chir. torn. viii. p. 45.

HERNIA.

745

tion of such a case is reckoned from the first
occurrence of symptoms, which at that period
are only those of indigestion, it will be an ex-
ample of a very chronic case of strangulated
hernia ; but these two stages of the disease
ought to be distinguished, for the treatment
that would be judicious in the one might be
injurious or destructive in the other. The in-
carceration of a hernia does not, moreover, ne-
cessarily involve its eventual strangulation, and
this constitutes a vast difficulty in the case, for
on the one hand few surgeons will advise an
operation until there is an obvious and decided
necessity for it, and on the other it is quite
possible in a case of this description that the
symptoms shall never be urgent, and yet the
intestine be found in a state of actual sphace
lus. I have seen a patient operated on in
whom the hernia had been down and the
bowels constipated for eighteen days. The
intestine was completely mortified.

That strangulation which is most rapidly
formed is the most severe in its symptoms and
the most dangerous in its consequences, but
between these extremes there is every possible
degree of intensity. A hernia has been gan-
grened in eight hours after protrusion. Mr.
Pott frequently mentions a single day as caus-
ing a most important difference in the case,
and 1 have found an intestine sphacelated en
the day following the first occurrence of the dis-
ease; however, in general the case is not so
quickly decided, although every moment of its
duration is pregnant with danger. The change
that is effected in the strangulated viscus next
demands attention. Its altered condition has
been always spoken of under the name of in-
flammation,* not from want of a perfect and
accurate knowledge of its pathology, but pro-
bably from the term appearing convenient and
being hastily adopted by one writer from ano-
ther. Yet as it is not inflammation, the name
is incorrect, and perhaps it has been injurious
in leading practitioners to attempt a mitigation
of the inflammation in the tumour, instead of
the more obvious indication, a diminution of
its size. The volume of a strangulated intes-
tine is always increased. In small hernias
(which in this respect can be more accurately
examined) the intestine, on the sac being divi-
ded, starts up and swells out as if relieved from
a compressive force. It always contains air,
and if cut into, a small portion of dark-coloured
serum will generally escape. Its colour, which
is manifestly occasioned by an accumulation of
venous blood, is at first of a reddish tint of
purple, soon however changing to a coffee

: * n Tne inflammation that takes place in stran-
gulated hernia is different from almost every other
species : in most cases it is produced by an unusual
quantity of blood sent by the arteries of the part,
which become enlarged ; but still the blood returns
freely to the heart, and the colour of the inflamed
part is that of arterial blood ; whilst in hernia the
inflammation is caused by a stop being put to the
return of the blood through the veins, which pro-
duces a great accumulation of this fluid, and a
change ot its colour from the arterial to the venous
hue. Cooper on Hernia, p. 20.

brown, and there is always more or less of
serum within the sac, as in every other case of
venous congestion. If unrelieved, dark and
fibrous spots appear which are truly specks of
mortification ; they very soon separate and
allow a discharge into the sac of a quantity of
putrid faeces and horribly fetid gas. This
done, the intestine either remains collapsed
within the sac, or retires spontaneously into the
abdomen.

In the meantime the parts covering the
hernia become inflamed; in the first instance
probably from sympathy with the deeper struc-
tures, afterwards obviously as an effort of nature
to get rid of the putrid and sphacelated matter
underneath. In the early stages the local symp-
toms are seldom very severe: the tumour is
scarcely painful, and will permit reiterated at-
tempts at the reduction of the hernia, and en-
dure considerable pressure, whilst the abdomen
may not be touched without intense suffering.
In a little time, however, it becomes tense and
tender to the touch, red, cedematous, and pitting
under the finger, which leaves a white impres-
sion for a moment after it has been withdrawn.
In fact, it is erysipelatous inflammation attack-
ing the coverings of the hernia, and its approach
is often accelerated by handling the tumour or
by repeated injudicious attempts to reduce it.
This (if the patient lives sufficiently long)
always terminates by the formationof oneor more
sloughs, on the separation of which the putrid
coverings are thrown off, and the contents of
the bowels being evacuated, the patient's life
may be saved, but with the inconvenience and
danger of an artificial anus at the groin. It is
seldom that the efforts of nature are thus ca-
pable of procuring relief, the contents of the
rupture being generally sphacelated, and incu-
rable mischief effected within the abdomen
long before its external coverings shew any dis-
position to burst spontaneously. I think the
condition of the sac has some influence on this
external inflammation. In all cases it under-
goes a less injurious alteration of structure than
the intestine contained within it, and is often
found comparatively sound while the latter is
in a state approaching to sphacelus. The supe-
riority of its vascular organization, its containing
a greater quantity of blood, and moreover the
volume of air always contained within the
bowel, will explain this pathological difference;
but the sac itself sometimes suffers from con-
gestion to a greater or less extent, and this, of
course, in proportion to the degree of con-
striction fixed upon its neck. An old hernial
sac, the neck of which is thickened and ac-
customed to its new position, and which is
itself probably one of the chief causes of the
stricture, will be less likely to suffer from an
interrupted circulation than a recent protrusion
just forced out through a narrow undilated
ring. It is in this latter case that the external
structures ought to be the soonest engaged, and
it has been in recent and acute cases of hernia
that I have seen the earliest examples of super-
ficial inflammation.

3. Such, during the progress of a hernia, is
the condition of the parts more locally engaged;

746

HERNIA.

but a far more serious because a more fatal
process is going forward within the abdomen.
It must be recollected that a gangrene of the
intestine when out of the abdominal cavity is
not necessarily fatal ; that the gut may die and
putrefy, and be thrown off by the results of
external inflammation and sloughing, and yet
the patient live for many years with an artificial
anus, or even have the natural passage per anum
restored again. Numberless cases of artificial
anus have thus occurred, not one of which
could have been saved if the sloughing of the
intestine was inevitably mortal. But soon
after the strangulation is effected, either from
the pressure on the viscus, which may be sup-
posed to have a material influence, or from the
mechanical obstruction to the passage of the
feeces, inflammation is established within the
cavity, commencing probably at the strictured
spot, and spreading thence with great rapidity.
The part of the peritoneum most engaged is
that which covers the line of intestine inter-
posed between the stricture and the stomach ;
the least, that which invests the walls of the
cavity. This inflammation may be in part
salutary, for it occasionally causes an adhesion
of the intestine at the neighbourhood of the
ring so firm that it cannot be removed there-
from, and thus provides for the occurrence of
an artificial anus subsequently without the
danger of any internal effusion ; but unless the
stricture is relieved at this time, and a check
thus given to the progress of the disease, the
intestines become matted with lymph, effusions
are poured out of a similar nature to those that
occur in other forms of peritonitis, and the
patient dies — not of the gangrene of the pro-
truded intestine, but of the peritoneal inflam-
mation within.

On opening the body of a person who has
thus died, the intestines above the stricture are
found inflamed, of a red or pink colour, greatly
distended with flatus and perhaps with faecal
matters ; below the stricture they are inflamed
also, but remarkably diminished in size. There
is always an effusion of lymph to a greater or
less extent glueing the convolutions of the
bowels together, and there is often on the sur-
face of the peritoneum not covered with lymph,
a dark appearance as if blood was ecchymosed
beneath it. Effusions are also constantly met
with, sometimes apparently of pure pus,
diffused, particularly throughout the spaces
formed by the apposition of the convoluted
intestines, sometimes more abundant, and con-
sisting of serum mixed with lymph in loose
and floating flakes; and occasionally a more
gelatinous substance is observed very much re-
sembling the jelly-like material that surrounds
frog-spawn in stagnant ponds. I have never
met the existence of gangrene within the ab-
domen in any case of death from strangulated
hernia.

The line of intestine, then, within the ab-
domen, and the loop within the sac, are diffe-
rently circumstanced. Above the stricture
there is active inflammation exactly such as
might occur idiopathically, presenting the same
morbid appearances, and accompanied by a

similar train of symptoms: below, there is a
state of venous congestion in which the vessels
endeavour to relieve themselves by pouring out
a serous effusion, and in which gangrene super-
venes with a rapidity proportioned to the tight-
ness of the constriction. Between these, and
immediately under the stricture, it is white,
pale, and bloodless all round for the space of
two or three lines, and appears to be diminished
in size more than it really is on account of the
great enlargement immediately above and below.
The condition of this strictured ring of intestine
is of the utmost importance in the progress of
the case, for it is not uncommon for it to ulce-
rate or to slough under the influence of the
continued pressure. I have seen an operation
admirably performed, and the intestine returned
under apparently favourable circumstances,
yet the patient sink and die in the course of a
few hours : a small hole existed in the con-
stricted spot, through which faecal matter had
escaped and become diffused within the cavity.
In another instance, from the anxiety of an
operator to inspect the condition of this spot
previous to the return of a hernia, the intestine
in the act of being drawn out tore almost as
easily as a wetted rag.

It will not be difficult to connect the symp-
toms of this disease with the morbid alterations
just described. When a hernia is about to
become strangulated, the earliest symptom is
in general pain, at first referred to the seat of
the stricture, but soon becoming diffused over
the abdomen, when the chief suffering is often
seated in the region of the navel. The belly
then becomes hard and tense, at first rather
contracted, but subsequently swollen and tym-
panitic : it is exquisitely tender to the touch,
cannot endure the slightest pressure, and in
some cases even the contact of the bed-clothes
is intolerable. The patient lies in bed with
his legs drawn up, and if possible his shoulders
bent forward on the trunk ; he cannot without
excessive torture endeavour to move himself in
any direction, and a moment in the sitting pos-
ture is not to be endured. Of course when
the whole canal of the intestine is constricted,
there must be constipation of the bowels ; yet
cases have been mentioned in which, though
all the other symptoms of strangulated hernia
were present, the discharges from the bowels
have not ceased, — a circumstance that has been
explained by the supposition that only a por-
tion of the circumference of the intestine was
engaged. I believe, however, that most of
these cases were delusive, and that when the
alvine discharges have continued to a very late
period, the case was one of incarceration in
which peritoneal inflammation may not be
established for a long time or perhaps at all ;
or else the practitioner was deceived by some
of those discharges from the line of intestine
below the stricture which are so frequently
brought away by the administration of enemata.
The explanation of the symptom is too mecha-
nical, particularly when it is recollected that
idiopatnic inflammation of the peritoneum will
generally (although not always) produce the
same effect, and that it is as regular, as constant,

HERNIA.

7-i7

and as complete in omental as in intestinal
ruptures. At a very early period of the case
the stomach becomes engaged, and there is
vomiting, at first in large quantity until the
contents of the stomach are evacuated ; it is
then less, dark -coloured, and excessively bitter;
and finally a substance is discharged having the
appearance and fetor of the feculent contents of
the great intestines. Considering the structure
and functions of the valve of the ileum, it ap-
pears curious how an anti-peristaltic motion
could be so completely established as to permit
of actual fcecal vomiting, and the fact (if it is a
fact) cannot be explained except by supposing
the action of all the constituent structures of
the intestine so deranged that the influence of
the valve is altogether lost. But it is more
than doubtful whether this material is really
feculent, although it is difficult from its sensible
qualities to consider it in any other point of
view; for I have frequently seen this vomiting
in cases where the herniae were formed of loops
of the lesser intestines, and therefore when the
contents of those beyond the iliac valve could
not have been thrown off; and in every case it
is difficult from the examination of the dis-
charge to determine its nature with accuracy.
After the stomach has been emptied of its
natural contents, the act of vomiting assumes a
very peculiar character : strictly speaking, it is
not vomiting or retching, nor is it hiccup, but
a slight convulsive effort like a gulp, which
brings up without much effort the quantity of
a single mouthful at a time. The forehead is
now bedewed with a cold and clammy sweat ;
the countenance presents a remarkable expres-
sion of agony and anxiety ; and the pulse is
small, quick, hard, and vibrating, as is the case
in all internal inflammations of vital parts.

After some further time (and the period is
very variable) the characters of the disease
undergo a fearful alteration. Mortification
attacks the incarcerated viscus, and in most
instances seems to bring the result of the case
to a very speedy issue. The tumour now loses
its tense feel, and becomes soft, flabby, and
perhaps emphysematous : in some instances it
retires altogether. The belly also may become
soft, and in general there is a discharge per
anum of dark-coloured and abominably offen-
sive faeces. This evacuation leads the patient
into the encouragement of false hopes, for he
may have seen his surgeon endeavouring to
procure stools during the progress of the case,
and combining this circumstance with the
removal of the pain and the comparative ease
he so suddenly experiences, he fancies so favour-
able a change to be the harbinger of recovery.
But the delusion lasts not long. The pulse
becomes low, weak, and faltering : often it
intermits irregularly. The countenance is
sunken, and assumes an appearance that cannot
be described, but is known by medical prac-
titioners as the " facies Hippocratica." The eye
has a suffused and glassy look, and there is a
certain wildness of expression very character-
istic. The forehead is bedewed with a cold
and clammy sweat ; the extremities become
cold ; the sensorium is affected with the low

muttering delirium, and death soon finishes the
picture.

These symptoms have been laid down as
indicative of mortification having taken place,
probably because the protruded viscus has
generally been found in that state ; and from
habit many practitioners have on their appear-
ance in cases of purely idiopathic peritonitis
decided on the presence of gangrene, and the
hopelessness of recovery. Such cases are hope-
less, and patients have died, but not of mortifi-
cation, for although these symptoms are present
in most cases of fatal peritonitis, yet dissection
after death very rarely exhibits gangrene in that
disease, and perhaps for this reason, that the
functions of the abdominal viscera are too im-
portant to life for a patient to struggle suffici-
ently long with their inflammation to permit of
mortification being established. Whilst the
inflammation is very active, and the serous
membrane dry, or lymph only secreted on its
surface, then is the pain intense, and the first
order of symptoms developed : but when effu-
sion has taken place, and the vessels are relieved
by the pouring forth of serum or sero-purulent
fluid, the pain abates, and the symptoms are
those of extreme debility. In confirmation of
this remark it may be observed that, when a
patient dies from any sudden effusion into the
peritoneal cavity, whether from a ruptured
intestine, or gall-bladder, or bloodvessel, or
from any other source, the symptoms from the
very commencement are those of debility and
collapse — the same sunken and anxious look,
the same feeble and fluttering pulse, and the
same kind of universal sinking of the entire
system.

However, although the symptoms may be
very formidable, the state of the patient is not
altogether hopeless. Art may still accomplish
a great deal, and even the operations of nature
alone and unassisted may succeed in prolonging
life, although under circumstances that render
life scarcely desirable. When the hernia has
proceeded to gangrene and the patient still
lives, the skin of the tumour assumes a very
dark red and livid colour, and then becomes
black in spots. The cuticle separates and peels
off in patches, and some one or other of the
sphacelated parts giving way, a profuse dis-
charge bursts forth, of a horribly offensive
nature. In the same way may the surgeon's
interference prove serviceable. It is related by
Petit, that travelling once, he met in the out-
house of an inn an unfortunate being thrown
on a heap of straw in a corner to die. He im-
mediately recognized the smell of a gangrened
hernia, and proceeded to give the poor fellow
all the relief within his power. He made an
incision, allowed the feculent matter to escape,
cleared away the gangrenous and putrid
parts, and having ordered a poultice left him
to his fate. On his return he found him able
to move about and perform active service within
the stable, and even free from the disagreeable
accompaniment of an artificial anus at the
groin. This is a most gratifying piece of suc-
cessful surgery, but it is not one that is very
frequently realised. In order to the possibility

748

HERNIA.

of an artificial anus being formed, the patient
and the hernia must be placed under circum-
stances so very peculiar that it will be easily
perceived how unlikely it is that they should
be united and combined in one individual.

1 . Although the protruded viscus has become
sphacelated, the inflammation within the ab-
domen must not have reached such a height as
to preclude the possibility of recovery.

2. Adhesions must be established between
the bowel and the peritoneum either at or im-
mediately above the neck of the sac, so that
when the stricture is free and the enormous
alvine accumulation allowed to escape, it will
be impossible for the gut to withdraw itself
within the cavity or be removed from the
external aperture.

And in order that the annoyance of the arti-
ficial anus should be subsequently removed, it
is necessary that the intestine and the perito-
neum to which it is adherent should retire into
the abdomen, and that the angle between the
two intestinal tubes should be diminished or
removed.

1. If the first of these conditions is indispen-
sable, it follows that the chance of recovery
with artificial anus is inversely as the acuteness
of the symptoms and the rapidity of their pro-
gress. As it is the inflammation of the intes-
tines that destroys the patient, it is pretty evi-
dent that after it has reached a given point, no
operation performed on the hernia and no
evacuation of the contents of the bowels can
arrest its progress, or cause the absorption of
the lymph, or of the sero-purulent fluid that
has been effused into the peritoneal cavity. In
operating on the living subject within twenty-
three hours after the first appearance of the
hernia, I have found the intestine sphacelated :
in this case, when the stricture was divided, the
discharge from the intestines within the ab-
domen was trifling in quantity, and in order to
relieve the patient, I was obliged to introduce
a gum-elastic tube for a considerable way into
the superior fragment of the bowel. He died
on the subsequent day, and on examining the
body the front of the intestines seemed to be
one mass of plastic lymph, which obliterated
every appearance of convolution, and must have
glued together the bowels in such a manner as
to prevent the possibility of a peristaltic motion.
In a case so aggravated no hope could be enter-
tained from the establishment of an artificial
outlet. It can now be easily imagined how
persons of a very advanced age,* and in whom
the symptoms of strangulation are mild and
chronic, recover with artificial anus, in short
that such a consummation is most to be ex-
pected in the cases to which the name "incar-
cerated" has been applied, whereas in most
instances of "strangulated" hernia its occurrence
is unlikely, and in many altogether impossible.

2. The second great requisite for the esta-
blishment of an artificial anus is, that adhesion
shall take place between the bowel and the
peritoneum, either at or immediately above the

* See Louis' Memoir on hernia followed by gan-
grene. Mem. de TAcad. Roy. v. 8.

neck of the sac, so that when the stricture is
free and the alvine discharges allowed to escape,
it will be impossible for the gut to withdraw
itself within the cavity, or be removed from the
external aperture. This adhesion has, I think,
been generally supposed to occur "during the
inflammation which precedes the gangrene/'*
but is nevertheless probably always not only
subsequent to it, but to the separation of the
unsound and sphacelated parts; and the at-
tachment is, not between the contiguous and
opposing smooth surfaces of the serous mem-
brane, but between the divided edges of the
sound portions of the tube remaining after the
slough has been thrown off, and the part of the
neck of the sac adjacent to them. I have ope-
rated on a great number of gangrened hernias,
and never found such an adhesion to have pre-
viously existed, neither have I ever met with it
on dissection, and I cannot conceive the possi-
bility of a spontaneous return after sphacelus
(an event that but too frequently occurs) if the
parts were thus attached together. Assuredly
if such adhesions were formed at so early a
peiiod, they ought to be much more frequently
found, and they would be amongst the most
calamitous complications that could attend a
hernia ; for they would offer an almost invinci-
ble obstacle to its reduction, or supposing the
bowel to have been pushed up by force, such a
sharp angular fold would be formed as must
prevent the passage of its contents and create
an internal strangulation. Nor is the consider-
ation of this fact practically unimportant, if it
leads us to adopt every possible precaution
that may conduce to the undisturbed progress
of this adhesive process, and at the same time
warns us not to be too sanguine in our expecta-
tions. I have (as I have said) operated on a
vast number of cases of gangrened hernia, not
one of which recovered with artificial anus:
some, the great majority, perished, as has been
remarked, in consequence of the inflammation
within the abdomen having reached an incurable
height ; some others sank exhausted and died,
the system being apparently worn out and
incapable of a recuperative effort : others still,
from a retraction of the divided end of the bowel
and the escape of its contents into the cavity ;
and one, from a cause which, as it has not been
mentioned by any pathological writer, may be
noticed here. On the spontaneous separation
of the sphacelated bowel, a frightful and incon-
trollable hemorrhage took place, some of which
flowed into the peritoneal cavity, and was found
after death diffused through the convolutions of
the intestines.

When a case has been so fortunate as to
permit of the formation of an artificial anus,
after the mortified parts and putrid sloughs
have been removed a cavity is seen, generally
irregular and puckered at its edge, leading
down to and communicating with the injured

* Scarpa on hernia, p. 323. See filso Travers on
wounded intestines. " Dans les hernies, ces adhe-
rences precedent la destruction des parties, et elles
previennent le plus souvent 1'epanchement des
matieres dans le ventre." — Dupuytren, Lc9ons
Oralcs, torn. ii. p. 197.

HERNIA.

740

intestine, from which the faecal discharge is
constantly trickling, and as there is often a suffi-
cient space for a portion of this to lodge and
remain, it may prove a source of troublesome
and dangerous ulcerations. In a shon time
the mucous membrane becomes everted and
protrudes, often, if neglected, to the extent of
several inches : it is a true prolapsus of the
membrane, not very unlike the prolapsus ani in
appearance. At the bottom of the cavity al-
ready mentioned, are the orifices of the intes-
tines, the superior of which is the larger, as it is
from it the discharge proceeds, whilst the
inferior is small and so contracted as frequently
to be discovered with difficulty. The partition
between the orifices is formed by the juxta-
position and adhesion of the sides of the intes-
tine : it is termed the " eperon" by Dupuytren,
and is larger and more obvious when a portion
of the bowel has been completely removed so
as to divide the tube into two parts, smaller
•when only a knuckle has been pinched up and
gangrened without engaging the entire circum-
ference. To this *' eperon" and double partition
the mesentery is attached, and the functions of
this membranous ligament are said to exert a
very important influence on the progress and
after-consequences of artificial anus.

Not only is the superior portion of the intes-
tine (that which is in relation with the stomach)
larger, but its extremity being fixed by the new
adhesions, the progress of its contents is greatly
facilitated, and according to Dupuytren actually
accelerated as to time. The inferior or rectal
portion, not performing its functions, becomes
diminished in calibre, and contains a white,
pulpy, albuminous material, which is sometimes
discharged by stool, but may remain undecom-
posed within it for months or even years. The
contracted condition of this portion of the gut
is of the highest importance to be attended to
in all instances where a recovery is possible or
likely to be attempted. This disposition of all
hollow structures in the body to accommodate
themselves to the bulk or quantity of their con-
tents has been already noticed, and to obviate
the inconveniences likely to arise from such
diminution, the older surgeons* strongly recom-
mended the use of enemata, in order, amongst
other advantages, to preserve the intestine in a
sufficient state of distension.

The progress and termination of a case such
as has been under consideration may be ex-
tremely variable. The aperture may be situa-
ted in the lesser intestine so high up or so near
the stomach that the space to be traversed by
the aliments and their period of detention are
shortened : their digestion is then incomplete
and nutrition so far impaired that the patient
sinks gradually, and dies from the effects of
inanition ; or a permanent artificial anus may
be established without a hope or a chance of the
natural passage ever being restored ; and this
seemed at one time to have been the great
object of surgical practice in these cases, for we
find M. Littre, a celebrated French surgeon,
actually tying up the lower portion of the gut

* See Louis' Memoir, loc, citat.

when he could find it, as if to preclude for ever
a possibility of the continuity of the tube being
restored. This is a most deplorable condition,
yet have patients endured the annoyance of a
permanent discharge at the groin for a great
length of time ; and in the Museum of the
School in Park Street, there is a preparation
taken from a man who had thus existed for
upwards of ten years. There is a curious in-
stance mentioned by Louis in which something
resembling the regular action of a sphincter was
clearly observable, and although the discharge
of the faeces was involuntary, yet it was periodical,
and the gut once evacuated remained closed
until a new accumulation took place. This
person, of course, was comparatively free from
that constant trickling of faeces which is the
patient's chief annoyance, and which, if not
palliated by some ingenious contrivance, abso-
lutely renders his life loathsome.

The natural passage of the faeces has been
restored. This is so desirable, so fortunate a
consummation, and its practicability so clearly
established by the circumstance of its being oc-
casionally accomplished solely by the operations
of nature, that it can be no matter of surprise
if surgeons have laboured to attain it and dili-
gently observed the entire process. An intes-
tine of which a portion has sloughed away is
placed in a very different condition from one
that has been simply wounded. When an en-
tire loop of bowel has been removed, the two
portions within the abdomen passing down to
the neck of the sac lie more or less parallel to
each other, or approach by a very acute angle :
they are in the same degree perpendicular to
the ring, and between them is that double parti-
tion termed "eperon" or buttress by Dupuy-
tren, and the " promontory" by Scarpa. Now as
the intestines are fixed and fastened in this posi-
tion, the canal can never again become conti-
nuous in directum, and therefore any material
that passes from the upper into the lower
portion must do so by going round this inter-
vening promontory. Even when only a small
fold or knuckle has been lost, although the
complete continuity of the tube is not destroyed,
and the partition is less evident and prominent,
still an angle must inevitably be formed of suffi-
cient acuteness materially to impede the pro-
gress of the faeces. In neither case, then, can
the wounded edge of one portion of the intes-
tine come to be applied to that of the other,
nor can adhesion or union by the first intention
ever be accomplished between them. In lieu
of this, however, the edges of the intestine be-
come united with the peritoneum opposed to
them, which must of necessity be the neck of
the sac, and then if the external wound can be
healed, a membranous pouch or bag is inter-
posed between them, of a funnel-shape, and
which serves as a medium of communication
and of conveyance for the faecal matters from
one portion of the tube into the other.

Reflecting on this pathological condition of
parts, it will not be very difficult to explain some
of the varieties observed in cases of artificial anus.
The chief obstruction to the re-establishment of
the canal is the intervention of the promontory.

750

HERNIA.

If it is so large or otherwise so circumstanced
as entirely to impede communication, and if
in this condition it is neglected, the discharge
must take place at the groin, and the disease is
permanent. Such, I believe, is the history of
most of those unhappy beings who have borne
about them for years this loathsome and dis-
gusting affliction, until relieved by a death that
could not have proved unwelcome. In a vast
number of cases the projection is not so great,
and although it may impede and delay, it does
not altogether prevent the passage of faeces
from one portion of the tube to the other:
then as the external wound contracts, the neck
of the sac forms into a membranous funnel or
canal of communication, and the faeces begin
to pass. The wound then heals, in some in-
stances leaving a small fistulous opening
through which a limpid, straw-coloured, but
fetid fluid constantly distils, whilst in others a
perfect and complete cicatrix is formed. But
we must recollect what happens in this seem-
ingly perfect cure before we can fully appreci-
ate the entire nature of the case, and the degree
of danger that always overhangs it. It is
evident that the viscus must (at least at first)
be firmly fixed at the situation of the cicatrix ;
that it no longer enjoys any freedom of motion,
and that it forms an angle more or less acute at
the place of adhesion. It is also probable that
the diameters of the two portions of intestine do
not correspond. Hence the process of diges-
tion is impaired, the patient must study every
article of food he consumes, and the slightest
indiscretion is followed by colicky pains, flatu-
lence, and tormina of the bowels; often there is
nausea, vomiting, loss of appetite, and a drag-
ging sensation at the stomach, this latter symp-
tom being explained by the omentum having
formed a part of the protrusion, and become ad-
herent at the new-formed cicatrix. It often
happens that the scar gives way, and a faecal
discharge takes place again, the groin thus
alternately healing up and bursting out anew.
This is more likely to occur in cases where the
very small fistulous canal has remained, and
therefore many surgeons have regarded this
event as more fortunate than where the cica-
trization has been complete ; for the course of
the fistula serves as a guide to direct the burst-
ing of the accumulation externally, whereas if,
as sometimes happens, the intestine should give
way internally, its contents are then poured
out into the peritoneal cavity, and the result
must be inevitably fatal.

The most curious circumstance connected
with the healing of an artificial anus is, that
the position of the united intestines and the
intervening infundibulum or funnel behind the
cicatrix is not permanent. "It is," says Scarpa,*
" a certain fact confirmed by a very great num-
ber of observations, that after the separation of
the gangrene the two sound segments of intes-
tine retire gradually beyond the ring towards
the cavity of the abdomen, notwithstanding the
adhesion which they have contracted with the neck
of the sac, whether this is caused by the tonic

* Scarpa, op. citat. p. 313.

and retractile action of the intestine itself and
of the mesentery, or rather by the puckering of
the cellular substance, which unites the hernial
sac to the abdominal parietes within the ring.
And this phenomenon is likewise constant and
evident even in herniae not gangrenous, but
merely complicated with fleshy adhesions to
the neck of the sac, and therefore irreducible.
In these herniae, the immediate cause of stran-
gulation being removed, the intestine, together
with the hernial sac, gradually rises up towards
the ring, and at last is concealed behind it."
The same fact has been observed by Dupuy-
tren,* who attributed it to the continued action
of the mesentery on the intestine. Many indi-
viduals who had been cured of artificial anus
without operation returned to the Hotel Dieu
at very remote periods, and died of diseases
having no relation to the original complaint.
The parts were curiously and carefully examined,
and the intestine, instead of being fixed to the
walls of the belly, was found free and floating
within the cavity. There could be no doubt
of the identity of the individuals, and moreover
a fibrous cord was seen extended from the point
of the wall of the abdomen which corresponded
with the former artificial anus, to the intestine.
This cord, some lines in diameter and some
inches in length, thicker at its extremities than
in the middle, covered by peritoneum, and
formed entirely by a cellular and fibrous tissue
without any cavity, was evidently produced
by the progressive elongation of the cellular
membrane that had united the intestine to the
wall of the abdomen ; and the cause which
had occasioned this elongation was nothing
else than the traction exercised by the mesentery
on the intestine in the different motions of the
body during life.

Having now endeavoured to describe gene-
rally the circumstances or conditions under
which protrusions of the abdominal viscera may
exist, I proceed to consider the peculiarities
that arise from situation, premising that it is
not my intention to enter very minutely into
the descriptive anatomy of those several situa-
tions in their normal or healthy states, but only
in reference to and in connexion with the ex-
istence of the disease under consideration.

Inguinal hernia. — When a viscus is pro-
truded through one or both of the apertures
termed rings, situated at the anterior and infe-
rior part of the abdomen, near the fold of the
groin, but above Poupart's ligament, the hernia
is termed inguinal. It may exist, therefore, in
three different conditions. 1. Where the in-
testine has been pushed through the internal
ring only, and is lodged in the inguinal canal :
it then appears as a small, round, firm, and
moderately elastic tumour. 2. Where it has
passed through the internal ring, through the
inguinal canal, through the external ring, and
dropping down into the scrotum of the male or
the labium pudendi of the female, appears as a
larger and more yielding tumour, of a pyrami-
dal shape, the apex of the pyramid being di-
rected towards the anterior superior spinous

* Le9ons Orales, torn. ii. p. 207.

HERNIA.

751

process of the ilium. As these are but different
stages of the same disease, both come under the
appellation of hernia by the oblique descent.
But, 3, when the viscus has been forced
through the parietes immediately behind the
external ring, and passes out through that natural
aperture only, it is then for obvious reasons
termed the hernia by direct descent; and
although the external characters of the tumour
are not always such as to point out the peculiar
nature of this protrusion, yet the relative posi-
tion of the intestine with respect to adjacent
parts must be somewhat different in these seve-
ral cases, a difference that will be found to be
of some practical importance.

The peritoneal sac, as viewed internally in
the direction of the iliac and inguinal regions,
is described by Scarpa as being divided into
two great depressions at each side, the medium
of partition being the ligament into which the
umbilical artery of the foetus had degenerated,
together with the fold of peritoneum raised by
that ligament. Of these fossae the superior or
external is the larger and deeper; it is that
within which the intestines are collected when
strongly compressed by the abdominal muscles
and by the diaphragm in any violent exertion ;
and from it inguinal hernia is most frequently
protruded, as the ligament and duplicature of
the peritoneum prevent the compressed viscera
lodged in this fossa from removing out of it to
descend into the pelvis. The situation of the
umbilical artery varies considerably: some-
times it is close upon the internal border of the
internal ring, in other subjects at the distance
of half an inch from it, or even more ; but it is
always at the pubic side of the epigastric ves-
sels. Thus, in its direction upwards and in-
wards towards the umbilicus it crosses ob-
liquely behind the inguinal canal : all herniae,
therefore, by the oblique descent pass out from
the external or superior abdominal fossa, while
those by the direct are in relation to and are
protruded from the inferior or internal. Inde-
pendent of this configuration there is nothing
in the peritoneal cavity as viewed from within,
to determine the occurrence of hernia at one
place rather than at another. The membrane
is in all parts equally smooth and polished,
equally strong,* tense, and resisting. This,
however, is not the case with respect to the
muscular and tendinous walls of the abdomen,
which vary very considerably in density and
strength in different situations, and in these
qualities dissection shews that the hypogastric
or inguinal regions are the most deficient and
therefore most disposed to permit of the occur-
rence of hernia.

In prosecuting the dissection from within
(which is by far the most satisfactory manner),
the peritoneum may be detached by the fingers
or by the handle of the knife in consequence of
the laxity of the cellular tissue connecting it to

* The strength of the peritoneum is proved by a
curious experiment of Scarpa's. He stretched a
large circle of this membrane recently taken from
the dead body, on a hoop like a drum, and found
it capable of supporting a weight of fifteen pounds
without being ruptured.

the adjacent external structures. The fascia
transversal is then comes into view, and in it the
aperture termed the internal ring, through
which the spermatic cord in the male, and the
round ligament in the female are transmitted.
This aponeurosis varies in density and thick-
ness in different individuals : it is continuous
with the fascia iliaca, and is connected with
the posterior edge of Poupart's ligament : it is
denser and stronger externally, and becomes
weaker and more cellular as it approaches the
mesial line. Where the internal oblique is
muscular, the connexion between it and the
fascia transversalis is extremely lax, cellular, and
easily separable ; but after it becomes tendi-
nous, the union is much more intimate, and the
fibres of the one can scarcely be distinguished
from those of the other unless by the difference
of their direction. In most subjects the internal
ring is very indistinct, its size, shape, and direc-
tion being in general determined rather by the
knife of the anatomist than by nature. So far
as the fascia is concerned, the external inferior
border of the ring is its strongest part, but its
internal edge seems to be the stronger as it is
supported by the epigastric vessels, and some-
times by the remnant of the umbilical artery.
Its size is about an inch in length, half an inch
in breadth ; its shape oval ; and the direction
of its longest diameter perpendicular or slightly
inclining from above downwards and outwards.
The position of the epigastric artery with re-
spect to the neck of the sac at once points out
whether a hernia is by the direct descent or not,
for it marks the internal or pubic boundary of
the internal ring. This vessel is occasionally
irregular in its origin, but in its normal or usual
state it comes off from the external iliac before it
has reached Poupart's ligament, and conse-
quently in that position it lies behind the bag
of the peritoneum, which it passes by forming
an arch, the concavity of which is directed up-
wards. It then appears in front, between the
fascia transversalis and the peritoneum, but
more closely attached to the former, with which
it remains when the membrane is torn away.
The vas deferens is seen coming from the pel-
vis obliquely upwards and outwards until it
reaches the spermatic artery, which, having de-
scended from above, nearly in a perpendicular
direction, meets the vas deferens at rather an
acute angle, the former being to the outside and
nearly in front of the latter. These vessels
having passed the fascia transversalis disappear
by arching round the epigastric artery and en-
tering the inguinal canal, and they define the
inferior margin of the internal ring. The re-
mainder of its border is not so very distinctly
marked, partly in consequence of a very deli-
cate fascia which is given off from it and passes
down a short way on the spermatic cord, where
it becomes indistinct and is lost; and partly
because the transversalis muscle lying before it
renders the view obscure. The internal border
of the internal ring is always (as stated by Sir
A. Cooper) midway between the anterior
superior spinous process of the ilium and the
symphysis pubis.

When a protruded viscus, then, is passing

752

HERNIA.

through this ring, it has the epigastric artery to
its internal or pubic side, and generally the
vessels of the cord behind it ; but a variety
sometimes occurs, for the hernia may protrude
exactly at the spot where the spermatic artery
and vas deferens meet each other at an angle,
and separate these vessels from each other,
leaving the artery rather to the outside and in
front, the vas deferens still occupying its usual
situation behind. After the hernia has passed
the fascia transversalis, it is still behind the
fibres of the internal oblique and transversalis
muscles, and has to pass a few lines (the dis-
tance varying in different subjects) before it
reaches the posterior surface of the tendon of
the external oblique. On prosecuting this dis-
section further by detaching the fascia trans-
versalis from, the transversalis muscle in a di-
rection downwards and outwards, the intestine
will be found to have entered a canal of an inch
and a quarter to an inch and a half in length,
its direction being obliquely downwards and
inwards to the external ring. This is termed
the inguinal canal, and is thus formed. Pou-
part's ligament, whether it be considered as a
portion of the tendon of the external oblique or
not, is powerfully strong and thick : to it the
fascia transversalis is firmly adherent behind,
and the thinner and more expanded fibres of
the tendon of the external oblique before.
Between these, then, a sheath is formed in
which the hernia is lodged, having in front the
tendon of the external oblique, and also covered
by the cremaster muscle, particularly that part
of it which has its origin from Poupart's liga-
ment. Behind it is the fascia transversalis,
and more internally or nearer the pubis the
conjoined tendon of the internal oblique and
transversalis, and below is Poupart's ligament.
Above, it is crossed obliquely by the inferior
margin of the internal oblique and transversalis.
These muscles have a Meshy origin from the ex-
ternal third of Poupart's ligament, from which
they pass in an arched form to be inserted by
a common tendon into the crest of the pubis.
Under this arch the viscus slips and thus places
itself anterior to the conjoined tendon before
passing through the external ring and becoming
a scrotal heniia.

Anatomists have not agreed in their descrip-
tions of the internal oblique muscle, although
a correct and accurate knowledge of the situa-
tion of it and of the transversalis in the neigh-
bourhood of the rings is indispensable to the
right understanding of hernia. According to Sir
A. Cooper* and Lawrence,f the upper part
only of the internal ring is shut up by these
muscles, leaving the lower unprotected, and con-
sequently, according to this view of the subject,
a hernia on entering the inguinal canal should
have them above it. CloquetJ states that the
inferior border of the transversalis passes on a
level with the superior, opening internally, but
the edge of the internal oblique is lower down,

covers the spermatic cord in the inguinal canal,
and passes over it to be inserted into the pubis
at the point where it escapes from the inferior
opening of the canal, that is, the external ring.
Scarpa* gives a different description still, where
he says, " towards the side at about eight lines
distance from the apex of the ring, the lower
muscular fibres of the internal oblique muscle
separate from each other to allow the sper-
matic cord to pass between them ;" and
Guthrief considers the occasional passage of a
hernia through the fibres of this muscle, and its
compression by them, to be no unfrequent cause
of strangulation. It is not easy to reconcile
these conflicting authorities, which in them-
selves demonstrate the fact that the inferior
border of this muscle exhibits some varieties in
its relation to the inguinal canal and internal
ring according to the extent of its origin from
Poupart's ligament. When a hernia is present,
I have always seen it arched over the neck of
the sac, and although I would by no means
assert that a rupture never takes its course
between these muscular fibres, yet I have not
met with an instance, and as I have observed
elsewhere, I imagine such an occurrence would
create a deviation from the usual relative
anatomy of the cremaster muscle with respect
to the hernial sac. — See ABDOMEN.

The inguinal canal terminates in front at the
external ring, which is formed by a separation
of the fibres of the external oblique muscle as
it passes inwards and downwards to be inserted
into the pubis. Almost immediately after the
muscle has become tendinous, a disposition to
this separation is observable, and a kind of split
is formed in the tendon, the edges of which
are, however, pretty firmly held in their re-
lative positions by fibres passing closely and
irregularly across from one to the other. These
fibres have been called the intercolumnar fascia.
Besides these there is a very remarkable ar-
rangement of tendinous fibres seeming to arise
from Poupart's ligament, and thence radiating
in an arched form (the convexity of the arch
looking towards the pubis) to form a strong in-
terlacement with the fibres of the external
oblique.]; Independent of these adventitious
bands the tendon itself, as itapproach.es the crural
arch and the pubis, seems to become thicker
and stronger ; and (as has been remarked by
Scarpa) in the dead body after the integuments
are removed and the parts left for some time
exposed, the lower portion of the aponeurosis
appears opaque and dense, while the part above
the umbilicus preserves its transparency, and
allows the fleshy fibres of the subjacent muscle
to be seen through it. The separation above
alluded to being effected, the tendon is divided
into two portions, termed the pillars of the
ring : the anterior or internal is broader and
flatter, and runs to be inserted into the pubis of
the opposite side, and the ligamentous sub-
stance that covers the front of this bone. The

* Page 6.

t Lawrence on Ruptures, p. 162.
$ Anatomy of Hernia, by Jules Cloquet, trans-
lated by M'Whinnie, p. 6.

» Page 25.

t Anatomy of Hernia.

% Sometimes termed Camper's fascia, from its
being so admirably delineated in the " Icones."

HERNIA.

753

inferior or external is rounder and more firm,
and attached to the external part of the crest or
tuberosity of the pubis. A triangular aperture
is thus formed of about an inch or an inch and
a quarter in length, the base of which, nearly
half an inch across, is situated at the pubis, from
which it tapers gradually off in a direction
upwards and outwards. For a neat demonstra-
tion of this aperture we must also be largely
indebted to the knife of the anatomist, its
edges being obscured by a fascia* which comes
off from them, and passing down on the cord
is generally of sufficient density to admit of
being traced as far as the tunica vaginalis testis.
This ring is never well developed in the female,
it then being smaller, rather of an oval figure,
and from its deficiency of size appearing to be
nearer the pubis than in the male: even in
subjects of the latter sex the size of this open-
ing exhibits considerable variety. When a
hernia has descended through it, the shape and
direction of the external ring are altered : the
inferior pillar is still more flattened and runs
in a more horizontal direction ; the superior is
banded in an arched form rather tightly above
it ; the shape of the entire ring is rendered more
oval and its direction more horizontal ; but still
its relative position with respect to the bone is
so far preserved that no hernia can pass, with-
out its internal edge resting on this bone.

In dissecting a hernia of this description
from without, after removing the skin and
cellular tissue more or less loaded with fat, the
fascia superficialis is exposed. This is a tegu-
ment investing most parts of the body, though
far more dense in some situations than in
others, and is situated beneath the subcuta-
neous fat, with which it is sometimes so much
identified as to render its demonstration diffi-
cult. At the groin it is usually well developed,
and is described as consisting of two distinct
laminae, but may (by such as are curious in
these dissections) by care be separated into
many more.f The superficial layer is very
lax, passes over and has no connexion with
Poupart's ligament, arid is very generally re-
moved along with the skin and fat by the in-
experienced dissector. Its removal exposes
some of the glands of the groin. The deep
layer is more membranous, and possesses more
of the determined character of a fascia. It
adheres intimately to the muscular fibres of the
external oblique, passes thence inwards over
the tendon, to which it cannot be said to be
attached, as the connecting cellular tissue is
extremely loose, and meets its fellow of the
opposite side at the linea alba, to which both
are attached. It has an insertion into the
pubis, and its adhesion to Poupart's ligament
is in many respects extremely intimate. Pass-

* This also has been called an intercolumnar
fascia, and a spout-like fascia, &c. It is to be re-
gretted that such a confusion of nomenclature ob-
tains in the description of these parts, — a confusion
always embarrassing to the student, and rendering
the subject uselessly perplexing and difficult.

t Velpeau describes three distinct layers. Aua-
tomie des Regions, torn. ii. p, 70.

VOI., IJ.

ing down in front of the thigh, it covers* several
of the lymphatic glands, or in many instances
leaves small apertures or deficiencies in which
glands are lodged : it then reaches the opening
in the fascia lata for the transmission of the
saphena vein, to the edge of which it adheres
more or less closely, and afterwards descends
upon the thigh, having this vein interposed
between it and the fascia lata. At the external
abdominal ring the fascia superficialis sends
down a sheath-like process, investing the cord
and descending down over the tunica vaginalis
and the testicle : it must, therefore, under any
circumstances give a covering to the hernial
sac. On the removal of this, the fascia that
comes from the edges of the pillars of the ring
is observed, and this is generally much thicker
and firmer than in the normal condition of the
parts. When so thickened, it also admits of
subdivision into several laminae. Immediately
underneath is the cremaster muscle, its fibres
spread out and separated so as to resemble a
fascsa, though in some instances the contrary may
be observed, and they are seen gathered into
bundles and greatly thickened. Still deeper
are three other layers of fascia, perhaps derived
from that which comes from the edges of the
internal ring, and finally the hernial sac is
exposed.

In herniae of moderate size, the spermatic
artery, veins, and the vas deferens are usually
found in one cord and enclosed in one common
sheath lying behind the sac : some exceptions,
however, to this rule are observed, one of which,
wherein the bloodvessels are situated on its
anterior and external surface, and the vas defe-
rens posteriorly and internally, has been already
noticed and explained. But there is another
deviation that seems to be occasioned by the
growth of the hernia, and the compression exer-
cised by it on the cellular substance connecting
the constituent parts of the cord together. It
can therefore only be met with in large and old
ruptures. Thus, as the tumour increases, it
causes this cellular tissue to be stretched just
as if the vas deferens and the artery were pulled
asunder in different directions, whilst the sac
insinuates itself between them, until finally the
vessels come to lie on one side of the hernia, or
it may be to occupy its anterior surface. The
greatest divarication of these vessels exists, as
might a priori be expected, towards the lower
part of the tumour; it is less towards the
middle, and scarcely if at all above, and in the
vicinity of the neck of the sac. A knowledge
of this fact may teach us to beware how we
prolong an incision very far down in operating
on large and old herniae.

Perhaps the next point of practical import-
ance to consider is, whether, with all this ana-
tomical and pathological information, it might
nevertheless be possible to mistake this disease
and confound it with any other affection. The

* The inguinal glands arc generally described as
lying between the layers of the superficial fascia.
On dissection, this has not appeared to me to be
the case,

3 P

7ol

HERNIA:

hernia just described may exist in two different
conditions ; one, in which it is still lodged within
the inguinal canal, and appears in the form of a
tumour in the upper part of the groin, termed
bubonocele ; the other, in which it has escaped
through the external ring, and having dropped
down constitutes scrotal hernia.

When the rupture has descended no farther
than the groin, there are but two affections that
can bear any resemblance to it : these are, the
testis itself whilst in the act of descending, if
this process has been delayed beyond the usual
period of life, and an enlarged inguinal gland.
However possible in cases of crural hernia (as
shall be noticed hereafter), a mistake of the
latter description is not likely to occur in the
disease under consideration, but there is an ob-
servation of Mr. Colles on this subject de-
serving of attention. "I do not suppose,"
says this distinguished professor, " that any
surgeon of competent anatomical knowledge
could mistake it for inflammation of those
lymphatic glands which lie in the fold of the
groin, but an enlargement, whether from a
venereal or any other cause, of two lymphatic
glands which lie on the side of the abdomen, as
high up but rather more internally than the in-
ternal abdominal ring; an enlargement of these
glands will produce appearances resembling
those of inguinal hernia."*

It seems almost surprising how the descent
of the testicle could possibly be mistaken for
a hernia when the mere examination of the
scrotum would throw such an explanatory light
upon the subject, but a consideration of the
following circumstances will be useful in solving
the difficulty. 1st, The detention of the tes-
ticle within the abdomen until an unusually
late period is by no means so infrequent an oc-
currence as is generally supposed even by sur-
geons in considerable practice : I have heard a
military medical officer observe on the great
number of young men that had passed before
him for inspection after enlistment, in whom one
and sometimes both the testes had not de-
scended. 2d, The symptoms of both affections
bear a general though not necessarily a close
resemblance ; for the situation of the" tumour
is exactly the same, and if the testicle is com-
pressed and inflamed, the pain and tenderness
and the inflammatory fever are to a certain ex-
tent like the symptoms of strangulation. But
I have not met the same costiveness, at least
the same obstinate resistance of the bowels to
the operation of aperient medicines, nor the
same vomiting, nor the same exquisite tender-
ness spreading over the abdomen, and the pulse
is not that small, thready, hard, and rapid vi-
bration that is produced by peritoneal inflam-
mation. In one case I perceived that pressure
on the tumour occasioned that sickening pain
and sensation of faintness which a slight injury
of the testicle so often produces; and I imagine
that in this case a light and very gentle per-
cussion might prove a useful auxiliary dia-
gnostic. But, 3rd, it does not always happen

* Colles's Surgical Anatomy, p. 46.

that the surgeon takes sufficient pains to inves-
tigate the disease before him. "He is apt,"
says Mr. Colles,* " at once to set down the case
as incarcerated hernia, a complaint with which
he is familiar, and does not suspect the exist-
ence of a disease which is to him perhaps ex-
tremely rare. Boys sometimes indulge in the
trick of forcing up the testicles into the ab-
domen, which may be followed by unhappy
consequences, for the gland may not descend
again, or if it does, perhaps a portion of in-
testine slips down along with and behind it,
which may then become strangulated, while its
presence is unsuspected and the symptoms
attributed to compression of the testis." A boy,
about seven years of age, had forced the left
testicle into the abdomen : ten years afterwards,
the inguinal ring having probably become un-
usually contracted, the testicle passed under the
femoral arch with all the symptoms of stran-
gulated hernia, on account of which he was
obliged to undergo the operation .-j-

When the hernia has become scrotal, it then
comes more to resemble diseases of the testis
and of the cord, but in general these are very
easily distinguished, and there are only three
that could lead a practitioner into error, and
then only through unpardonable carelessness ;
the hydrocele of the tunica vaginalis testis,
the hydrocele of the spermatic cord, and the
varicocele or a varicose condition of the veins
of the cord.

There is not much likelihood that hydrocele
of the tunica vaginalis could, in its earlier
stages, be mistaken for hernia: it commences
below and increases in an upward direction,
while a hernia proceeds from above downwards;
and at first in cases of hydrocele, the ring, the
cord, and all these parts can be accurately felt.
As the disease proceeds and the water reaches
the ring, a diagnosis is not so easy; still in
almost every case of rupture the testis and the
cord, particularly the former, can be easily felt
lying behind and at the bottom of the tumour,
which is not the case in hydrocele. Besides,
hydrocele is lighter as to weight ; it gives a
sensation of fluctuation to the touch ; it never
exhibits that soft doughy character that belongs
to omental hernia : moreover it is diaphanous,
and the light of a candle can be seen through
it, if the tumour is examined in a darkened
room.

A collection of water within the sheath of
the cord must, I should think, be rather an
infrequent occurrence ; at least it has not
fallen to my lot to meet with many examples
of it. Still the practitioner must be aware of
the possibility of the disease, and that both
from the nature of the accident that occasions
it, and many of the accompanying symptoms, it
may very readily be mistaken for hernia. A
young man fell with his groin against the edge
of a tub, and in an incredibly short space of
time afterwards a colourless elastic tumour
appeared in the usual situation of hernia.

* Colics, op. citat.

t Scarpa, op. citat. p. 235.

HERNIA.

7.r>5

He was admitted into the Meath Hospital
under the care of the late Mr. Hewson, and
though some years have now elapsed I can
well recollect the variety of opinions pronounced
upon it. It could be partially pushed up, but
re-appeared instantly on the pressure being re-
moved : it was slightly influenced by coughing,
and it was extremely tender to the touch. As
the patient was not confined in the bowels, and
in fact there was no urgency of symptom, no
active treatment was adopted, and the tumour
gradually disappeared. It had probably been
an effusion of fluid into the sheath of the cord.
The manner in which these diseases are said to
be capable of discrimination is as follows. Let
the tumour be pushed up if possible, and the
finger of the operator still be pressed against
the ring: if it is a hernia, such pressure will be
sufficient to prevent a re-descent ; but if it is
only a fluid, it will insinuate itself by the side
of the finger and the tumour shortly re-appear.
Scarpa* denies the sufficiency of this test in
cases of omental hernia of small size, when
situated so high up as to occupy and dilate the
inguinal ring, and asserts that he had repeatedly
observed omental inguinal hernia of a cylin-
drical form, which, when scarcely returned, re-
appeared again as before without the patient
having changed his posture or made the slight-
est exertion ; and in like manner hydroceles of
the spermatic cord, which, when pushed beyond
the ring, remained there as long as the patient
kept himself in the supine posture without
making an exertion. He seems to rely more
on the difference of consistence and regularity
of surface in the two tumours, and on the cir-
cumstance of the hydrocele being always broader
inferiorly, contrary to what is observed in
omental hernia.

A varicose enlargement of the spermatic vein
is not easily confounded with hernia, unless it
has increased to such a size as nearly to occupy
that side of the scrotum : it is longer in pro-
portion to the diameter of the tumour than
hernia usually is, and its surface is hard, knotty,
and uneven.f These circumstances, however,
are not sufficient to remove all obscurity, and a
farther investigation must be made by placing
the patient in the horizontal position and endea-
vouring to empty the vessel ; then let him
stand up whilst firm and accurate pressure is
maintained upon the ring. If it is a hernia,
the tumour will not re-appear; but if varicocele,
it will return as speedily or perhaps more so
than if no pressure had been made. Mr.
CollesJ mentions that a varicose state of the
cord may be combined with hernia, throwing
great obscurity on the nature of the disease,
and for obvious reasons increasing the diffi-
culty of its management.

Inguinal hernia by direct descent. — I now

* Op. citat. p. 98.

t These symptoms are not certainly characte-
ristic of varicocele. There is a preparation in the
Museum of Park Street taken from a man who
exhibited them all during life. His disease was an
enlarged, knotted, and contorted condition of the
vessels of the cord.

\ Op. citat.

proceed to offer a few remarks on the other
form of inguinal hernia, — that by direct descent,*
which occurs when, instead of passing through
the canal, the protruded viscus is pushed out
immediately behind the situation of the ex-
ternal ring, through which it passes directly.
The inferior part of the inguinal canal is the
weakest of all the parietes of the abdomen.
Externally, independent of the external oblique
muscle, it is protected as far as the external
third or half of Poupart's ligament by the
fleshy fibres of the internal oblique and trans-
versalis muscles, and by the fascia transversalis,
which is dense and strong in this situation, but
becomes gradually weaker internally, and is
nearly lost before it reaches the mesial line.
More internally it is supported by the conjoined
tendon of these muscles, but as it arches over
the spermatic cord that portion of the peri-
toneal cavity which corresponds with the inferior
and posterior part of the inguinal canal must
depend on the fascia transversalis alone, now
becoming- weaker and less capable of resist-
ance. More internally still, and immediately
behind the external ring, this region is best
supported, and there are many natural obstacles
to the production of hernia in this situation.
Besides the fasciae already mentioned as tending
to prevent the separation of one pillar of the
ring from the other, and thereby offer an ob-
stacle to the passage of any viscus through it,
there is anotherf of a triangular shape arising
by a pretty broad base from the crest of the
pubis, and inserted into the lineaalba for about
an inch or an inch and a quarter. It lies
behind the tendon of the external oblique, and
before that of the internal oblique and trans-
versalis, which latter it strengthens materially,
and its external edge contributes to close up a
part of the external ring. The edge of the
rectus muscle extends itself laterally sufficiently
far to occupy one-half or one-third of the space
behind the external ring, and moreover here the
conjoined tendon is particularly strong. Not-
withstanding these supports, this part is weak ;
and yet when a hernia occurs here, it is not in
consequence of yielding or stretching, but be-
cause the conjoined tendon actually undergoes
laceration.

The causes of this hernia are said to be three-
fold :J an unnatural weakness of the conjoined
tendon ; its absence altogether in consequence
of malformation ; and its being ruptured by
direct violence. Of these, the second is not
likely to occur, and an example of it had not
been met with by Sir A. Cooper at the time of
the publication of his work : the other two in
effect amount nearly to the same thing, or at
least stand towards each other in the relation of
a predisposing to an immediately exciting

* The internal inguinal hernia of Hasselb.ich,
Jules Cloquet, and Velpeau : hernia on the inner
side of the epigastric artery of Sir A. Cooper, and
a combination of ventral and inguinal hernia ac-
cording to Scarpa.

t This is frequently termed Colles's fascia, having
been first accurately described by that writer.

} Cooper, p. 51.

3D2

756

HERNIA.

The hernia by direct descent is distinguished
from the oblique, 1st, by the appearance of the
groin, the apex of the tumour being at the
situation of the external ring, and there being
no enlargement whatever in the direction of the
inguinal canal : this diagnostic, however, has
been found fallacious, for in old oblique hernia
the internal ring is dragged down and made to
approach the external so as to appear to form
one continuous opening. Nor is it easy to
point out the difference even in dissection ex-
cept by the position of the epigastric artery,
which in case of oblique descent always lies to
the pubic side of the neck of the sac. The
neck in some of these cases appears to be
arched over and strongly constricted by the
superior portion of the ruptured conjoined
tendon, which in these cases is more than
usually developed, and (as it were) in a state of
hypertrophy. It was probably this appearance
th;Lt led to a belief that strangulation was occa-
sionally produced by the action of these mus-
cles. '2nd, By the relative position of the
tumour with respect to the different structures
composing the cord. The cremaster muscle in
any hernia cannot be felt, but it occupies nearly
its usual position in this, being spread out like
a fascia in front of it, but rather towards its
outside. The spermatic cord properly so called
passes on its external rather than on its pos-
terior side; and although all its constituent
vessels may be separated in this as in any other
species of large and old herniae, yet generally
there is less divarication in this, and the parts
lie together more compactly. 3rd, " This
tumour differs from the common bubonocele in
being situated nearer the penis.'7* This is cer-
tainly true when it is only bubonocele; but
when it has descended into the scrotum, the
same difficulty that has been noticed as apper-
taining to old ruptures must also obtain here.
In applying this diagnostic the student must
recollect that the internal edges of both herniae
are equally near to the pubis : it is by looking
to the external border of the neck of the tumour
that he can render the test available. Scarpaf
states that this hernia is returned without being
attended by the gurgling sound : this, however,
is an observation perfectly new to me, and
•which I can by no means verify. Lastly, these
hernise appear more suddenly and attain a larger
size more rapidly : frequently they appear as scrotal
ruptures almost from the earliest period. This,
however, is still an uncertain criterion, and in-
deed with the assistance of all these circum-
stances it is always so difficult and frequently
so utterly impossible to establish a diagnosis,
that no operation should be undertaken under
the conviction of the disease being certainly of
one form or of the other.

This rupture should present to the anatomist
the same number of layers of fascia as that by
the oblique descent, the fascia transversalis sup-
plying the place of that given off from the edges
of the internal ring; J but the young surgeon

* Cooper.

t Scarpa, op. citat. p. 84.

$ The internal spout-like fascia.

should be cautioned not to expect the same
facilities of demonstration in the living subject
that he possesses in the dead. In the former,
the operator often meets with layer after layer
of fascia, numerous beyond his expectation, and
to which he can give no name ; and it is no un-
common circumstance for him to operate on
and return a rupture without being able to say
of what nature it was— nay, even as to its being
inguinal or crural.

CRURAL OR FEMORAL HERNIA takes place
at the superior and internal part of the thigh,
below the fold of the groin ; the intestine pass-
ing out of the abdomen behind Poupart's liga-
ment, between it and the transverse ramus of
the pubis, through an aperture that has been
termed the crural or femoral ring. A know-
ledge of the constitution, size, and boundaries
of this ring must be of the last importance to
the practical surgeon, and accordingly no part
of the body has been examined with more
minute attention ; yet if by these labours ana-
tomy has gained in accuracy of information and
very diffuse description, still the student is not
much the better for it, inasmuch as almost
every anatomist has adopted views peculiar to
himself, and thus in the details a degree of con-
fusion has been produced that is extremely em-
barrassing to the beginner. I shall, therefore,
avail myself as little as possible of authorities,
and endeavour to describe these parts as they
appear upon dissection, commencing from
within, which is perhaps the best mode of
studying the anatomy of every species of
hernia.

The distance between the anterior superior
spinous process of the ileum and the angle of
the crest of the pubis is in the well-formed
female about five and a half inches in length,
along which space Poupart's ligament is
stretched like a bow-string from point to point.
The distance from the ligament thus extended,
backwards to the edges of the ileum and pubis
forming the border of the pelvis, varies accord-
ing to the elevations and depressions of these
bones ; but the entire forms a very considerable
space, which is, however, in general so well
filled up that unless under ^peculiar circum-
stances this region affords sufficient support
and protection to the viscera of the abdomen.
On examining the corresponding peritoneal sur-
face within, the membrane is found capable of
being detruded only at one spot, internal to the
view, and about an inch and a half distant from
the symphysis pubis. Here, there is a natural
aperture varying in size in different subjects,
into which the finger may be pushed by a little
violence, and a small artificial hernial sac like
a thimble be thus produced. On tearing off
the peritoneum it is easy to observe the dif-
ferent arrangements that serve to support and
strengthen this region of the abdomen.

From Poupart's ligament three distinct layers
of fascia pass off in different directions. The
fascia transversalis has been already described
as passing upwards on the front of the abdomen,
where it is gradually lost. From the inferior
and posterior part of the arch another fascia
passes, at first downwards, then upwards and

HERNIA.

backwards, to expand itself over the iliacus
interims and psoas muscles ; and it is therefore
called the fascia iliaca. These fasciae are per-
fectly continuous as far inwards as the external
border of the artery, and form a smooth and
strong membranous wall for the abdomen in
this situation, rather attached to Poupart's liga-
ment than coming off or derived from it.*
These fasciae separate at this spot and unite
again between the artery and vein, thus forming
a sheath for the former vessel : in like manner
a separate sheath is formed for the vein, when
they again separate and leave a small opening,
which is the crural rin°r, but unite before they
reach Gimbernat's ligament, to the abdominal
surface of which they give an investment, but
here the fibrous structure is very weak and
differs little in appearance from cellular mem-
brane. These fasciae then form a flat, broad
funnel, which has three apertures at top, and the
membranous septa are of the greatest use in
binding the anterior and posterior faces of this
fuunel together : hence a hernia cannot escape
through fn company with the artery nor with
the vein, and hence also the vein is not com-
pressed nor its circulation interfered with, even
although a hernia close to it is in a state of
strangulation. This funnel descends on the
vessels, to which it becomes firmly attached, at
about an inch and a half below Poupart's liga-
ment, and, according to some anatomists, is
there reflected up again on the vessels forming
a cul-de-sac or bag. I thus consider the
crural ring properly so called to be an aperture
formed by a deficiency in the fascia iliaca and
transversal is, just as the internal inguinal ring
is formed in the latter membrane alone. It is
occupied by a loose cellular tissue, and in
general by a small absorbent gland.

This ring is of a different size in different
individuals ; and where it is large, the person
may be said to have an hereditary or congenital
disposition to the disease ; but a liability to it
may arise from accidental circumstances also.
It is obvious that in proportion as the space
beneath the crural arch is well filled, and the
muscles tense and plump, the aperture at the
ring must be small ; also that it will be larger
according to the greater breadth between the
spinous process and the pubis, or as the space
under the crural arch is deep. Hence it may
be explained why this kind of rupture is fre-
quent amongst women who have borne many
children, with whom the parietes of the abdo-
men are relaxed ; less frequent amongst young
and healthy unmarried females, and scarcely
known amongst men, the pelvis of the male
being narrower, and his muscle better developed
by use and exercise.

The crural arch or Poupart's ligament is

* Their importance in strengthening this part of
the abdomen is proved by an experiment of Mr.
Colles. " Make in the aponeurosis which covers
the iliac muscle an opening capable of admitting
the finger. Pass it between the aponeurosis and
surface of the muscle, and you will be enabled, with-
out much difficulty, to push the finger under Pou-
part's ligament down to the fore part of the thigh."
Colles, op. citat. p. 68.

nothing more than the inferior pillar of the
external inguinal ring, and is (as has been before
stated) inserted into the crest of the pubis ; but
it has another attachment to this bone, which,
being in intimate relation with femoral hernia, I
have delayed the description of until now. As
the ligament approaches the pubis, its inferior
edge becomes twisted upwards and backwards
towards the linea ileo-pectinea, into which it is
inserted for a length of from a half to three
quarters of an inch. Its shape is triangular, its
posterior attachment being somewhat shorter
than its anterior ; and its base, which has its
aspect towards the vein, is somewhat lunated.
In the male its situation corresponds nearly
with the external inguinal ring; and the sper-
matic cord rests on it just as it is about to pass
from the inguinal canal.

The fibrous funnel-like sheath already des-
cribed is itself lodged within a cavity which
may be called the crural canal, and is thus
formed. The fascia lata of the thigh in front
has two origins, one from the whole length of
Poupart's ligament, the other from so much of
the linea ileo-pectinea as gives origin to the
pectinalis muscle, and from the ligament of the
pubis. This latter portion having passed down
the thigh unites with the former below the en-
trance of the saphena into the femoral vein,
below which point they form one continuous
sheath for the muscles of the limb. The por-
tion, however, which comes from Poupart's
ligament requires more attention. At first it
lies completely in front of the upper part of the
thigh, and of course leaves a triangular space
between it and the other portion, in which are
lodged the funnel-shaped fascial sheath, with
its contents, the artery and vein, lymphatic
vessels, and some glands. About half an inch,
or in some subjects a little more, below Pou-
part's ligament the internal portion of this fascia
appears to be wanting, leaving the vessels un-
covered by it as far down as the point of union
of the two fasciae : I say appears to be wanting,
because the fascia lata is really continued over
this space, joins the pubic portion internally,
and sends a process upwards to be inserted
into the linea ileo-pectinea, external to the
lunated edge of Gimbernat's ligament, and be-
tween it and the edge of the femoral ring ; but
it is here so thin and cellulated that it is
generally removed in the dissection. When
thus disposed of, the firm portion of the external
fascia lata, as it passes to join the internal,
assumes a lunated form above and below, and
thus the entire apparent deficiency is made to
appear of an oval figure, the edges of which are
crescentic, and which have been called by the
different names of Hey's ligament, Burns' liga-
ment, and the crescentic edge of the fascia lata.
A finger pushed from above through the crural
ring will easily feel the superior margin of this
aperture, and its influence on hernia in this
situation will soon be made apparent. The
femoral or crural canal then is from one-half to
three-fourths of an inch in length, and is formed
by the fascia lata : it is bounded above, anteriorly
by Poupart's ligament and posteriorly by the linea
ileo-pectinea; below, anteriorly by the crescentic

758

HERNIA.

edge of the fascia lata or Hey's ligament, and
posteriorly by its pubic portion : both externally
and internally it is bounded by the junction of
these two portions of fascia. Gimbernat's liga-
ment, which is usually described as forming the
internal boundary of the crural ring, rarely fills
up more than half the space between the crest
of the pubis and the femoral vein. This canal,
as being composed of fascia, is firm, and un-
yielding : it cannot be influenced by the actions
of any muscle in the neighbourhood, nor even
so much as is generally supposed by the posi-
tion of the limb. It should follow from this
constitution of parts that any hernia thus re-
strained should forcibly compress the vein and
artery before it suffered strangulation itself, and'
so it would if the protrusion had relation to
this canal alone, and was not contained within
its own proper portion of the funnel-shaped
sheath already described.

The neck of the sac of a femoral hernia, then,
has behind it the fascia iliaca and the ligamento-
cartilaginous material that covers the sharp edge
of the lir.ea ileo-pectinea : internally it has the
junction of the fascia iliaca and transversalis,
the attachment of the fascia lata to the liriea
ileo-pectinea, and Gimbernat's ligament ; inter-
nally it must also have the spermatic cord in
the male and the round ligament in the female;
anteriorly it has the fascia transversalis and
Poupart's ligament, and immediately above the
neck and in close contact with it is the sper-
matic cord, of course including the spermatic
artery : externally is the membranous slip in-
terposed between it and the femoral vein. The
epigastric artery is also external to it, but
although this vessel is somewhat irregular both
in origin and position, yet the full breadth of
the vein must be always interposed between it
and the neck of the sac. But there is an
irregular vascular distribution that must be
borne in mind. In a great number of subjects
(perhaps one out of every four or five) the
obturator artery, instead of coming off from the
internal iliac, arises by a common trunk along
with the epigastric, which it soon leaves, and
passing downwards and inwards crosses the
superior aperture of the femoral canal before it
dips into the pelvis to reach the obturator
foramen. In this course it sometimes passes
the border of the canal posteriorly, but much
more frequently in front; and in this latter case,
if a hernia existed, the vessel would embrace
two-thirds of the circle of the displaced peri-
toneum close to and immediately above the
neck. It appears, then, from these anatomical
relations that in all subjects a considerable
degree of danger may arise from too free and
unguarded a use of the knife in operation — a
danger that is necessarily enhanced in the male
subject: indeed in consequence of the risk of
hemorrhage Scarpa seemed disposed to trust to
dilatation and laceration of Poupart's ligament
for relieving the stricture, and where these
means were insufficient he recommended a new
and particular direction to be given to the
incision. But from careful dissection and ex-
amination of these parts I am disposed to
believe there is always sufficient space to free a

stricture without endangering either the sper-
matic or the irregular obturator artery. It must
be recollected that if the intestine is sufficiently
liberated to permit the passage of gas through
the immediate seat of the stricture, its return is
perfectly practicable, and a very small incision
will be sufficient to accomplish this. Now
these vessels lie, not on the neck of the sac, but
above it ; and there is quite space enough to set
the stricture free without interfering with them :
when they are wounded, it is in consequence of
the introduction of the cutting edge of the
bistoury too far within the stricture.

When a portion of intestine has escaped
through the femoral ring, (and by reason of the
small size of the aperture herniae here are
seldom large,) it lies at first within the crural
canal, where it is restricted by the fascia lata,
and its existence recognized with difficulty. It
has happened that patients have perished from
the incarceration of a small fold or knuckle of
intestine without the circumstance ever having
been discovered during life. But after it has
passed the crescentic edge of Key's ligament,
and is relieved from the pressure of the fascia,
it comes forward, and if it increases farther, its
direction is rather inwards and upwards, so
that it may assume the position of an inguinal
hernia to the extent of being mistaken for it.
Having proceeded so far, the hernial sac has
assumed somewhat of the form of an arch : it
has passed, first downwards through the
femoral canal, then forwards under the sharp
edge of the fascia lata, either passing through
the weak cellular portion of it or pushing it
before, and then upwards and inwards in front.
The hollow of this arch looks upwards, and is
occupied by the crescentic edge of Hey's liga-
ment. Perhaps this particular position of the
hernia, as well as the extreme straitness and un-
yielding nature of the crural canal, has con-
tributed to the frequency of strangulation to
which this form of hernia is liable.

When a person stands erect and without
exertion, Poupart's ligament forms nearly a
direct line between the anterior superior spinous
process of the ileum and the crest of the pubis,
and all the fasciee connected to it are in their
natural state and sufficiently relaxed ; but if the
thigh is strongly extended or the body bent
backward, the ligament then becomes tense and
is arched backward toward the thigh. The
effect of the general tension of the limb in this
position would be to convert the arch formed
by the hernia into an angle, against the hollow
of which the edge of Hey's ligament would be
firmly compressed, and a sufficient degree of
resistance thus created to the return of the
venous blood to produce a congested condition
of the viscus. The operation of such a cause
as this can hardly be considered as permanent,
but the mischief once commenced is not easily
controlled, and an intestine might soon be
placed in such a condition as to render incar-
ceration at the ring inevitable.

The situations at which crural hernia may
be strangulated have not been satisfactorily
described, although there is no subject on which
more anatomical labour has been bestowed. If

HERNIA.

759

I was to speak from my own experience alone,
I should say that though the hernia itself is
superficial, the seat of the strangulation is
always deep — somewhere at or in the imme-
diate neighbourhood of the neck of the sac. I
found the opinion partly on the dissection of
subjects that had died of the disease, but more
particularly on the phenomena I have observed
during the progress of an operation on the
living: still the experience of one individual
can scarcely ever be sufficient to establish a
great pathological principle, and there is autho-
rity that cannot be questioned for believing
that crural hernia is frequently strictured at a
far less depth from the surface. Besides the
neck of the sac, by which this hernia is con-
fessedly strictured in very many cases, Sir A.
Cooper places the seat of strangulation, first in
the crural sheath and semilunar or lunated
edge of the fascia lata, and secondly in the
posterior edge of the fascia lata.* Mr. Colles
says that the neck or constricted part of crural
hernia does not always appear at the same
depth from the surface, and explains the cir-
cumstance thus : "The hernia having descended
into the femoral sheath, it escapes through one
of those apertures in it for transmitting the
lymphatic vessels, and also passes through a
corresponding opening in the iliac portion of
the fascia lata. As it passes through a small
aperture in each of these parts at nearly the
same spot, it must there be liable to great con-
striction ; for these two layers of fascia will be
compressed together, and thus their strength
and resistance be considerably augmented.
Hence we should find the seat of stricture in
strangulated femoral hernia frequently to be at
some distance below and to the pubic side of
the crural ring."f The descriptions of Hey and
Burns I cannot profess clearly to understand,
and I fear they were taken rather from sound
subjects than from those in which hernia? were
actually present. Scarpa does not distinctly
point out the anatomy of the seat of stricture,
but from the general bearing of his descriptions,
and above all from the anxiety he expresses
relative to the danger of wounding the sper-
matic artery in operation, which vessel, if pre-
sent, must lie close to the neck of the sac, I
would hazard an opinion that he believed the
seat of strangulation to be always deeply
seated.

In dissecting this rupture from without, or
in operating upon it in the living, it will be
found to He at a different depth from the sur-
face, and to possess variety in the number of
fascial coverings according to its position with
reference to the parts already described. Thus
it may be placed within the crural canal,
within that triangular space formed by the
fascia lata ; or having passed beyond its inferior
opening or falciform edge, it may present
more superficially. In the former case, after
the division of the common integuments, the
skin and fat, the superficial fascia is exposed
and may consist of many layers — at all events

* Cooper on Hernia, part ii p. 1 1.
t Colics' Surgical Anatomy, \>. 77.

of two : next is the dense and resisting fascia
lata of the thigh ; and deeper still, the funnel-
shaped fascia in which the crural ring is situated.
Between this latter and the sac another fascia
has been described under the name of the fascia
propria, which may be supposed to be formed
by a condensation of that cellular tissue already
described as occupying the crural ring; but I
have never been able to satisfy myself as to the
existence of this as a distinct membrane, and I
must again caution the young operator not to
expect to meet with laminae of fascia as de-
scribed or demonstrated by the anatomist. A
dexterous and careful dissector may make al-
most as many layers of fascia as he pleases.

After it has passed the inferior border of the
crural canal and appeared more externally, the
coverings of fascia to be expected must depend
on the view taken of the anatomy of this part.
If it is believed that the hernia having cleared
this point merely swells out on being relieved
from the pressure, without passing or pushing
through any of the superincumbent structures,
then in order to come down upon the sac it
would be necessary to divide the skin and
cellular tissue, the different laminae of the fascia
superficialis, the cribriform portion of the fascia
lata, the anterior portion of the funnel-shaped
fascia, and the fascia propria. If, on the other
hand, it is supposed that the hernia has escaped
through one of the openings in the femoral
sheath, and a corresponding one in the iliac
portion of the fascia lata, it will lie more super-
ficial by the absence of these investments. In
either case the last layer of fascia most adja-
cent to the sac is almost always remarkable for
density and strength.

The general symptoms of this affection are
the same with those of inguinal, such as the
appearance of the tumour, its diminution or
disappearance in the recumbent position, and
the impulse imparted to it by coughing, sneez-
ing, &c. : its peculiar symptoms are explicable
by its anatomical relations. 1. The crural
hernia is generally small and its increase slow :
the size of the ring and the compression ex-
ercised on it by so many superincumbent
layers of fascia will be sufficient to account for
this, and also will shew why this rupture is
almost always painful, and why position has so
much effect on it, relief being constantly ob-
tained by bending the thigh on the pelvis and
rotating the limb inwards. 2. The peculiar
manner of growth, its first passing downwards,
then forwards, and then upwards and inwards,
is caused by the attachment of the funnel-like
fascia to the vessels at the superior part of the
thigh, and by that of the fascia superficial
to the fascia lata near the entrance of the
saphena vein ; thus its shape is never pyramidal
like that of inguinal ; it is globular or oval, and
its longest diameter is transverse. 3. I have-
already mentioned its prevalence amongst
females advanced in life.

As the testicle is more subject to disease
than any structure at the top of the thigh, there
are more affections with which scrotal hernia
may be confounded; but on the other hand,
when a doubt arises on the subject of crural

HERNIA.

hernia, the diagnosis is vastly more difficult, and
often the surgeon has to be guided by the gene-
ral symptoms of peritoneal inflammation rather
than by the results of local examination, how-
ever carefully performed. Mr. Colles* states
that "this species of hernia is liable to stran-
gulation even before it can be felt externally,"
— an observation I was enabled to verify a few
months since in a case where a very small
knuckle of intestine had not passed the inferior
aperture of the femoral canal, but was lodged
in an absorbent gland, which seemed to have
been hollowed out to receive it.f But the
hernia may be much larger and still not disco-
verable in consequence of some unfortunate
complication : I have seen a case of incarce-
rated hernia | in which an abscess was seated
at the superior part of the thigh immediately
in front of the sac ; and after the pus had been
evacuated, some time elapsed before decisive
symptoms pointed out the existence of the
more formidable disease behind. There is,
in the Museum in Park-street, a preparation
exhibiting a fatty tumour growing on the exter-
nal surface of a hernial sac. The patient from
whom it was taken was the subject of opera-
tion, and after the integuments and fascia had
been divided and this tumour presented, some
doubts were at first entertained as to the pre-
sence of a hernia beneath it ; but on careful
examination the operator discovered the hernial
tumour, and cutting cautiously through the
other, opened the sac, in which a knuckle of
intestine was found incarcerated. The opera-
tion was successful, and the patient recovered.
"In many instances," says Mr. Colles, "the
difficulty of discriminating the disease is consi-
derably increased by an enlarged lymphatic
g'and lying anterior to a very small hernia."

Perhaps there are no two affections more
liable to be mistaken for each other than crural
hernia and an enlarged lymphatic gland; and
however apparently distinct the two affections
may be, and however easy it may seem to form
a diagnosis in theory, still the best surgeons
speak of the difficulty of discriminating between
them, and many acknowledge having fallen
into the error themselves. It has happened
that a patient has had a hernia on one side and
an enlarged gland on the other, and when
symptoms of strangulation became urgent, it
was the gland that was considered to be the
most pressing, and it was selected for the opera-
tion. I recollect two cases which occurred
nearly at the same time ; one in which there
was a very minute hernia at the left groin,
which had been regarded as a swelled gland,
and the patient died of the effects of its stran-
gulation ; the other a case of pure peritoneal
inflammation, in which the patient happened to
have a swollen gland in the groin, which was
actually cut down upon and exposed, but the
operation did not much injury, for the patient

* Op. citat. p. 83.

t This curious case occurred in the Meath Hospi-
tal in the summer of 1835.

J I use this term in the sense hitherto employed,
not implying perfect strangulation.

subsequently recovered. It has been said that
a diagnosis can be established by attention to
the following circumstances. The hernia fol-
lows on some sudden exertion, on a blow or a
fall, and appears suddenly and at once ;
whereas the gland in the commencement is-
very small, perhaps like a moveable kernel,
and increases slowly and by degrees. Besides,
this diagnostic will be greatly assisted if there
is a chancre or other sore to account for the irri-
tation and inflammation of the gland; but on
the other hand the hernia does not always
assume its given size at once, it is often
so small at the beginning that the patient is not
aware of its existence, and so far from appear-
ing suddenly after a violent exertion it may
have been present for months without being
perceived. The hernia receives an impulse
from coughing or sneezing, and retires or be-
comes smaller in the recumbent posture, which
are not observed to happen with the gland ; but
then an enlarged gland may be complicated
with a hernia, and the symptoms so mixed and
confused that a diagnosis may be very difficult.
It is said that a gland maybe moved about and
withdrawn from its situation in a slight degree,
and if it can there is no great danger of mis-
taking it ; but when it has arrived at the size or
occupies the place which could make it resem-
ble a hernia, then it does not admit of being
moved under the fascia, and the diagnosis is
almost impossible. Fortunately, a crural hernia
does not often consist of omen turn, but when it
does there is nothing more likely to exhibit the
characters of a gland in a state of chronic dis-
ease, and I know not how the two cases can be
accurately distinguished. Here the physical
evidence derived from a gentle percussion (as
already noticed) is utterly and completely
valueless.

Lumbar or psoas abscess is another affection
that may be confounded with femoral hernia,
and Mr. Colles states that he had known the
mistake to have been committed. These diseases
resemble each other in the following circum-
stances. Both present very nearly in the same
situation at the bend of the groin, are firm and
elastic; coughing gives to each the same or a
similar impulse; and there are cases on record
in which psoas abscess disappeared under pres-
sure or by the patient assuming the recumbent
posture. Yet I think the two cases not very
difficult of distinction. Psoas abscess is a dis-
ease of youth; it does not often occur in the
adult except as a critical abscess after fever, or
in connexion with caries and curvature of the
spine, in either of which cases the collateral
circumstances will point it out ; whereas femoral
hernia is the disease of married women, and of
course will not be likely to occur at the same
period of life with the abscess. A sense of
fluctuation is generally perceptible in psoas
abscess; not so with hernia. The abscess is
preceded by pain and weight in the loins and
by shivering. It is a scrofulous complaint, and
there will probably be other indications of the
diathesis, such as the transparent skin, the
thickened upper lip, or perhaps ill-conditioned
sears about the neck. Any of these symptoms

HERNIA.

761

taken singly may prove but an indifferent dia-
gnostic, but in the aggregate they establish such
distinction that it must be the result of sad in-
attention or of actual ignorance if any serious
mistake is committed.

It has been stated that a varix of the saphena
vein may present symptoms and appearances
strongly resembling crural hernia, inasmuch
as the tumour disappears under pressure or in
the horizontal posture, and returns again imme-
diately on these influences being removed, and
also as it receives a certain degree of impulse
from coughing or sneezing. From anatomical
considerations it would almost seem impossible
that such an error could be committed, and at
first sight the observation seems to have been
made for the purpose of creating nice distinc-
tions and rendering the subject apparently com-
plete rather than for any practical utility. A
case, however, is related by Petit, who distin-
guished the real nature of the tumour by its
dark-coloured appearance and by the general
varicose state of the remainder of the vein. If
difficulty is experienced in any particular case,
it may be easily resolved by making pressure
on the trunk of the iliac vein above Poupart's
ligament, when the tumour will re-appear, even
although the patient maintains the horizontal
posture.

" Fatty tumours are not unfrequently found
on dissection occupying the exact situation of
crural hernia. I have not had an opportunity
of seeing any case of this kind in the living
body, but have had occasion to remark at least
five or six instances of it every season in the
dissecting room, from which I presume such
tumours are more common than is generally
suspected. In all those instances the fatty tu-
mour was connected with or rather seemed to
grow from the outer surface of the peritoneum
lining the crural ring; and the inner surface of
this membrane when viewed from the abdomen
had a contracted, wrinkled, and thickened ap-
pearance, resembling very closely the appearance
of a reduced hernial sac. Whether the perito-
neum had been protruded in these instances
I cannot pretend to say ; nor can I venture to
lay down the symptoms which should guide us
in our diagnosis in the living body. This
much at least is obvious, that these steatoma-
tous tumours will not be accompanied by
symptoms of strangulation/'*

Umbilical hernia. — The navel is the remnant
of an aperture that had been situated nearly in
the centre of the front of the belly, but nearer to
the pubis than to the ensiform cartilage: it is
placed in the linea alba, and of course Its edges
are tendinous. During foetal life it serves for
the transmission of the umbilical vein and arte-
ries, but its size is greater than would merely
suffice for the passage of these vessels, in order
that the circulation of the blood through them
should suffer no interruption by accidental com-
pression ; and in a foetus of seven months the
edge of the aponeurotic opening is still thin,
weak, and unresisting. After birth, when the

* This passage is copied from Colles's Surg. Ana-
tomy, p. 84.

navel string (as it is called^) has dropped off,
the umbilical aperture begins to close, until
finally that puckered cicatrix is formed, the
appearance of which is so familiar; but the
periods at which this process commences and is
completed, and the circumstances that may
occur to interfere with it, are of some importance
with reference to the phenomena of hernia.
Scarpa says that it begins immediately, and that
if the finger is passed up the peritoneal wall of
the abdomen in a child two months afterbirth,
not only will the navel be found firmly formed
and completely cicatrised, but there will be a
knot or elevation felt at this spot, shewing that
it is then really stronger than most other parts
of the abdominal parietes. Lawrence states
that the contraction commences about the third
or fourth month after birth, and thence inculcates
the necessity of an infant being tolerably accu-
rately bandaged anterior to that period in order
to prevent the occurrence of umbilical rupture
from its struggles or its cries. It is not of
much consequence which of these opinions
may be correct : probably both are so to a cer-
tain extent, for the opening is larger in some
infants than in others, and will require a longer
time to close, and the process of obliteration
does not commence in all exactly at the same
period after birth. Whatever variety may
exist in this respect, when the process is com-
plete the umbilicus can never afterwards be
called an aperture; it never again re-opens; and
when ruptures are observed in after-life seem-
ing to occupy this situation, it will be found on
examination that some neighbouring parts of
the linea alba have given way, and the disease
more strictly belongs to the ventral than to
umbilical hernia.

It appears then that by the salutary provi-
sions of nature the front of the abdominal pa-
rietes is well supported, and the contained
viscera protected from protrusion ; and even if
the operations by which the umbilicus is closed
should be accidentally suspended or interfered
with, (as by the presence of a hernia for in-
stance,) the disposition is not lost, and the aper-
ture preserves its tendency to close and become
obliterated for the first five or six years of
childhood. Thus at any time within that period
there may be a reasonable probability of obtain-
ing a permanent cure of umbilical hernia;
whereas after the age often or twelve years this
disposition ceases to operate, or at least is
greatly impaired, and there is little or no chance
of so fortunate an occurrence.

The condition in which the umbilicus exists
at and after birth divides the herniae that occur
in this situation into different orders according
as they may appear at the period of birth or
afterwards. Scarpa considers the disease to
consist of only two species, the congenital and
the adventitious — the congenital being that
which appears in the infant when born, and the
other occurring at any subsequent period.
Lawrence speaks of three kinds, the congenital,
that which appears at birth, and in which the
protruded viscera are lodged in the umbilical
cord; the umbilical hernia of children occur-
ring after the navel has been formed, but pro-

762

HERNIA.

trading through the original deficiency in the
linea alba; and the hernia of adults, which has
some peculiarities that shall be noticed here-
after.

The congenital umbilical hernia seems to
depend rather on a deficiency of the anterior
walls of the abdomen than on any other cause,
and in the cases in which it is observed, the
aperture at the navel is much larger than it
should naturally be, and its tendinous edges
excessively thin and weak. The deficiency of
the abdominal parietes ranks amongst natural
malformations, and it is astonishing to what an
extent it has been observed. The entire of the
tendinous front of the belly has been found
imperfect, and nearly the whole of the viscera
displaced, thus forming an immense rupture
covered at its base and for some extent farther
by the skin and superficial investments of the
body, and in its remaining part by the transpa-
rent spongy substance of the umbilical cord.
The contents of these ruptures are greatly varied :
the liver or a portion of it, the spleen, the
stomach, the greater and the lesser intestines
have all been occasionally found thus circum-
stanced, but more particularly the omentum,
which, as might be anticipated from its situation,
is observed to constitute a part of almost every
umbilical hernia both in the old subject and in
the young. Whenever there is such a defi-
ciency in the abdominal parietes, the pressure
an infant undergoes in coming into the world
materially contributes to the production of
hernia, and accordingly it is observed most fre-
quently after a protracted and difficult labour;
and if it is large, and the contents of the ab-
domen extensively deranged or displaced, it is
in general fatal, the infant seldom surviving
beyond two or three days, and perhaps not so
long. In this affection there seems to be a
want of correspondence between the size of the
viscera and that of the abdominal cavity, the
former appearing enlarged and swollen ; and
there is seldom a possibility of returning the
rupture, or of maintaining it so if reduced.
There is in general also in these cases some
other malformation or incomplete development
to account for the fatality that so uniformly
attends them. But if, on the other hand, the
hernia is small, the case is by no means neces-
sarily attended with danger: the rupture may
be reduced, but it has a tendency to return when-
ever the child cries or makes any other exertion,
and it is extremely difficult to restrain it by a
bandage ; but if it can be kept up for a few
months, the umbilical aperture closes as it
would have done if there had been no pro-
trusion, and the cure is permanent and com-
plete.

If, before the navel has become cicatrized and
closed, a portion of any viscus should happen
to be protruded through it, and its progress
towards obliteration thus interrupted ; or if the
contraction has been delayed longer than usual,
and an aperture thus left ready to favour the
escape of a part of intestine from its natural
situation, the rupture will be of the second
form mentioned, namely, the umbilical hernia
of the child. This differs from that of the

infant inasmuch as it is covered by the skin and
the cicatrized knot of the navel, and does not
lie within the cord ; and from that of the adult,
so far as, if replaced and prevented from again
protruding, the aperture will gradually contract,
and thus a permanent cure be obtained, which
is scarcely to be expected at a more advanced
period of life. It has been already mentioned
that Scarpa considered the perfect contraction
of the umbilicus to be completed in about two
months, and at the end of that time that it is
even firmer than other parts : he moreover
seemed to think this part materially strength-
ened by the remains of those vessels which
before birth made up a part of the cord. The
umbilical vein passing from the navel upwards
towards the liver, and the hypogastric arteries
passing downwards, are at the umbilicus united
by a cicatrix to the skin and to each other, and
contribute to prevent the yielding of the part as
soon as they become ligamentous. The point
of union of these vessels must be pushed
forwards as well as the integuments in adven-
titious hernia, and hence it happens that when
the umbilical aperture is only of its natural
size, the rupture that takes place (if any) is
small; and in cases where it is large and the
abdominal parietes deficient in this point, the
tumour is natter and more compressed than
might have been otherwise expected, and some
of these vessels are found lying on it and
forming a part of its covering.

In persons more advanced in life in whom
the opening in the tendon had been perfectly
closed, Scarpa denies that it ever becomes
relaxed again, and therefore states that the rup-
tures which occur from over-distension, from
pregnancy, or as the sequelae of dropsy, are
not situated in the original umbilical canal, but
in some part of the linea alba that has more
recently given way, and of which the umbilicus
happens to form a part. lie states further that
the linea alba is not equally strong and firm in
all its parts ; that above the navel it becomes
gradually thinner, and in women »vho have
borne many children it is uneven in consistence,
and in some parts so weak as to be liable to
yield and tear on a very slight exertion. Hence
it happens that these ventro-umbilical ruptures
generally occur rather above the navel; and the
almost obliterated remains of this cicatrix (for
by the distension it becomes nearly smooth) is
scarcely ever observed to occupy the centre of
the tumour, but is found to one side and almost
placed inferiorly. In the dissection of these
tumours a laceration or fissure is constantly
met with in the linea alba, sometimes transverse,
but more generally longitudinal, and this is one
reason why the umbilical ruptures of old per-
sons are not susceptible of a radical cure, for
there is a great difference between a natural
opening, the tendency of which is to contract
and close, and one made by the yielding and
laceration of part of the linea alba or other
tendinous portion of the abdominal parietes,
which certainly cannot be supposed to be en-
dowed with strong reparative properties.

There was a question formerly raised as to
whether umbilical hernia possessed a peritoneal

HERNIA.

763

sac, and it was generally believed that no such
investment had any existence in the disease.
Garengeot in his paper on singular species of
herniae expressly states that ruptures of this
kind were deficient in this particular, and he
was followed by Petit and almost all the elders
of our profession, who, to spare themselves the
labour of investigation, copied from each other
errors as well as truth. It is really curious to
observe how a mistake could have so long
maintained its ground that could have been set
at rest by half-an-hour's dissection ; and indeed
it is in some respects surprising how such an
opinion came to be entertained at all. In every
case of umbilical hernia there must of neces-
sity be a sac, because the peritoneum is not
deficient at the navel, and the vessels that pass
within the cord do not enter the cavity : they
lie anterior to it, and are partly invested by the
membrane, which is entire and complete behind
the navel, and neither intestine nor omentum can
be protruded without pushing it out before it,
and thus constituting a proper hernial sac. It
may be that in large umbilical herniae the peri-
toneum shall have become very thin, so that the
peristaltic motions of the intestines may be
easily perceived through it from without; or it
may have been burst accidentally, and in either
of these cases there will be an appearance as if
there had been in reality no sac. And more-
over, the peritoneum immediately behind the
navel is not connected to it by the same loose
and distensible cellular tissue that unites it to
other parts : it is here very closely joined, and
consequently in small ruptures only occupying
this spot there will be no appearance of a sepa-
rate and distinct sac, although the peritoneal
covering is really there notwithstanding. It
must be borne in mind, however, that invest-
ments of umbilical ruptures are always very
thin, and a proportionate degree of caution is
requisite in cutting through them during ope-
ration. There are no distinct layers of fascia
here as in other ruptures, no laminae to sepa-
rate one by one and one after another. In the
congenital species the contents of the sac are
merely covered by the peritoneum and the
sheath of the cord. In the infantile, the
coverings are the skin and cicatrix of the navel
and the peritoneum ; and in the adventitious
kind or ventro-umbilical we meet the skin, then
the superficial fascia, which is very thin and
weak on this part of the abdomen ; next the
cellular tissue that had united the peritoneum
to the adjacent structures, and which may have
become condensed so as to form a kind of
fascia propria ; and lastly, the peritoneum or
hernial sac itself.

In almost every case of umbilical hernia
occurring in the adult, omentum has formed
part of the contents of the sac, at least the ob-
servation has been so universally made that the
rule may be considered as established. In
general it lies before the intestine in such a po-
sition as to conceal it altogether and make it
appear as if no other viscus was engaged ; but
sometimes the intestine makes a passage through
it and presents first when the sac is opened : or
both these structures may be coiled and twisted

together in such wise as to render it difficult to
unravel and separate them one from another,
and highly perilous to return them in that con-
dition into the cavity lest strangulation should
take place within. From the circumstance
also of containing omentum, umbilical ruptures
frequently become irreducible, this structure,
when protruded, becoming thickened and en-
larged and occasionally loaded with fat, so as
to preclude the possibility of its being again
returned through the tendinous opening. Or
adhesions may have formed between the
omentum and the intestine, or between either
or both of these and the sac : in short, the
rupture may become irreducible from any of
the causes already mentioned as capable of
producing such a condition of parts, but the
one first alluded to, namely, the thickening and
alteration of the omentum, is the one most
generally observed.

This altered condition of the omentum has
also a paramount influence on the case even at
a more remote period. Let it be supposed that
symptoms of strangulation have supervened,
and an operation been deemed necessary to
preserve existence, the presence of this mass
will be likely to prove extremely troublesome.
Every surgeon is conversant with the different
opinions that have been entertained as to the
manner in which irreducible omentum should
be dealt with. Some* speak boldly enough of
cutting it off and returning any part that might
remain, or allowing it to slip back into the
abdomen without feeling any apprehension
from the possibility of haemorrhage. Some
have tied a ligature around it to cause it to
slough, and Mr. Heyf employed a ligature in
another way and with a different view, namely,
by applying it so tight as gradually to cut
through the omentum by the process of ab-
sorption, but without entirely destroying the
circulation through the included part. ScarpaJ
left the omentum, merely covering it with the
sides of the hernial sac and dressing it lightly
until suppuration appeared, when, he said, the
pedicle by which it hung might be safely tied
and the mass cut away. I notice this diver-
sity of opinion not for the purpose of incul-
cating any one line of practice, but to shew
that the omentum cannot be left there with
safety. It is at all times and under every cir-
cumstance not very highly organized or able to
sustain disease; still less so is it when altered
from its natural arrangement, converted into an
unwieldy mass of fat, and exposed to the in-
fluence of the atmosphere in an open wound.
Sometimes it runs into tedious and unhealthy
suppurations with profuse and wasting dis-
charges ; more generally, if the patient is old
and debilitated, into mortification, which may
(if the subject lives sufficiently long) pass on
to the unaltered omentum within the abdomen,
nor cease until it has reached the stomach.

* Pott, op. citat. p. '6. Petit and Ponteau,
Mem. de 1'Acarl. Royale de Cbir. torn. vii. p. 338.
Colles's Surgical Anatomy, p. 100.

t In this he was anticipated by Moreau, Mem.
de 1'Acad. Roy. de Chir. t. vii. p. 344.

t Op. citat. p. 420.

764

HIBERNATION.

The symptoms of umbilical hernia are
easily understood by referring to those points
in which it differs from ruptures situated else-
where. In the infant the tumour appears long
and thin, according to the quantity of viscera
protruded through the aperture of the navel, and
projects downwards on the belly : its coverings
are almost transparent. In the more adult
subject, if the patient is thin the tumour is of
a pyriform figure, and when permitted to in-
crease without restraint becomes very large
and hangs pendulous towards the pubes. If
he is fat it may form a less circumscribed
swelling, broad and flat, apparently extending
in every direction round the umbilical aperture.
The sensation imparted to the finger is of a
soft and doughy tumour slightly moveable
under the skin, but sometimes in consequence
of the presence of intestine in the rupture it
may possess some elasticity. Occasionally,
after an omental hernia has remained for years
without producing much inconvenience, it sud-
denly enlarges towards the centre and assumes
a conical chape, the apex being soft and elastic,
the base hard and more solid : in this case
there has probably been a fresh protrusion of
intestine which has burst through the omentum
and requires instant attention, as so circum-
stanced it is extremely liable to fall into a state
of strangulation. The collateral symptoms,
such as nausea, flatulence, colicky pains, &c.,
are more severe and more frequent in umbilical
than in any other form of hernia, a circum-
stance that has often given rise to the idea that
the stomach formed some part of the protrusion,
but perhaps it is unnecessary to resort to such
a supposition, for probably the herniae of the
linea alba that have been described as con-
taining part of the displaced stomach were in
no wise different from ordinary umbilical
ruptures as to their contents, for the omentum
being protruded will be sufficient to account
for every aggravation of symptom.

When the hernia is strangulated, it is said
that the symptoms are less severe and less
urgent than in other species of ruptures, a cir-
cumstance that has also been accounted for
from its so often containing omentum alone.
Sir A. Cooper states that more cases of stran-
gulation occur in the seasons when green vege-
tables are plenty than in others, which would
seem to favour the idea of its being often caused
by the use of flatulent or indigestible sub-
stances. But (except with reference to pre-
vention) it is of little consequence how it may
be caused, or whether its progress is rapid or
not. When once formed, it must be reduced ;
and it runs its course with sufficient rapidity to
render it extremely alarming. It has destroyed
a patient in less than eighteen hours, and
although such severity is not generally to be
expected, yet in this or in any other kind of
hernia the smallest unnecessary delay can
never be justified.

" Sometimes a small mass of indurated fat,
situated between the peritoneum and its union
with the aponeurosis of the abdominal muscles,
makes its way insensibly through the separated
fibres of the linea alba, and is at last elevated

externally in form of a tumour which seems o
have all the characters of an omental hernia.
The existence of this species of tumour through
the linea alba is not only a certain fact and de-
monstrated by several observations made on the
dead body by Morgagni, by Klinkosch and
several others, but it is also proved that it
makes its appearance in other parts of the
linea alba besides that to which the umbilical
vein corresponds internally. It may occur that
a person in whom a similar small tumour has
existed for a long time in the course of the
linea alba may be attacked from a quite diffe-
rent cause by violent colic, with nausea, incli-
nation to vomit, and interruption to the alvine
excretions. The surgeon, in similar circum-
stances, is easily led into error," (and Scarpa
committed the mistake himself,) " presuming
that the tumour is a true incarcerated hernia of
the linea alba, subjecting the patient to an ope-
ration which has no connexion with the cause
of the disease." Never having seen any similar
tumour, I have copied the above passage from
Scarpa : they are probably of the same nature
with those described by Mr. Colles as occa-
sionally presenting at the crural ring. The
resemblance must be strikingly obvious to
every reader.

( William Henry Porter.)

HIBERNATION ; etym. hiberno, to win-
ter, to pass the winter; syn. lethargy ; errone-
ously, torpor; Fr. sommeil hivernal ; Germ.
Winterschlaf'<md Sommerschlaf ; a term chiefly
applied to express that condition in which cer-
tain animals pass the winter season.

How often have I been struck with admira-
tion in observing how variously the Creator has
provided for certain of the insectivorous tribes,
the swallow and the bat, for example, against
the period when the sources of their daily food
are cut off, when spring and summer yield to
autumn and winter, and insects disappear ! The
first emigrates to a more genial climate where
its nutriment still abounds ; the second sinks
into a deep sleep, in which food is unnecessary,
and which continues through the dreary season
of cold and famine.

It has not hitherto been distinctly ascertained
to what extent the state of hibernation prevails
in the animal kingdom ; the bat, the hedgehog,
and the dormouse, are the genera which present
us with the most marked examples of this sin-
gular physiological condition in this country ;
to these the elegant authoress of " Sketches of
Natural History " has added the water-rat and
the wood-mouse, observing of the former —

" And when cold winter comes and the water-
plants die,

And his little brooks yield him no longer supply,

Down into his burrow he cozily creeps,

And quietly through the long winter-time sleeps."

But before we proceed to discuss this ques-
tion of natural history, we must consider that
of the physiology of hibernation.

There is, in my opinion, an ultimate law of
animal existence, which seems to regulate the
different forms in which the different classes of
animals present themselves. The quantity of

HIBERNATION.

765

respiration is inversely as the degree of irritabi-
lity of the muscular fibre, the former being
marked by the quantity of oxygen consumed in
a given time, ascertained by the pneumatome-
ter,* the latter by the force of galvanism neces-
sary to demonstrate its existence. The bird
tribes have a high respiration and a low irrita-
bility ; the reptiles have a high degree of irrita-
bility and little respiration. This law obtains
not only in the different tribes of animals, but
also in the different stages or states of the same
individual, the structural changes from one
stage to another being always a change from a
lower to a higher respiration, and from a higher
to a lower degree of irritability, and the change
of state, a change in the opposite direction :
thus the changes from the egg to the bird, from
the tadpole to the batrachian form, from the
larva to the chrysalis and the insect condition,
are changes in which, whilst a due ratio is con-
stantly maintained, the quantity of respiration
is augmented and the degree of irritability
diminished; on the other hand, the physiolo-
gical changes in the degree of activity in ani-
mals, during sleep, for example, but especially
in that remarkable change which is the subject
of this article, the respiration is diminished
whilst the degree of irritability is, pari passu,
augmented.

On what this susceptibility of change de-
pends, and especially on what the power of
taking on an augmented irritability depends, is
at present unknown. But 1 think I may affirm
that it is upon this power that the capability of
passing into the state of hibernation reposes. I
suppose that all animals have the faculty of
sleeping ; during sleep the respiration is slightly
diminished, the irritability probably proportio-
nately augmented — probably one ultimate ob-
ject of this state of repose ; but the phenomenon
has its appointed limit which it cannot pass.
In certain animals, that limit is not so con-
fined,— the quantity of respiration is still further
diminished, the degree of irritability still further
augmented, and the deeper sleep, or lethargy,
of hibernation takes place.

During this lethargy, the law of the inverse
ratio of the respiration and of the irritability
still prevails, and the animal merely puts on a
reptile state in these respects. Were the respi-
ration to be diminished without the appointed
augmentation of the irritability, the heart would
cease to be stimulated, and the animal would
die, as in the cases of torpor and slow asphyxia;
were the respiration augmented without the
proportionate diminution of the irritability, the
heart would be over-stimulated, and death
would alike ensue, as in the case of a hiberna-
ting animal too suddenly roused from its lethar-
gy, and as (probably) in the case of an animal
placed in pure oxygen gas.

The difference between the hibernating and
all other animals then is, an ultimate faculty of
assuming an augmented degree of irritability of
the muscular fibre — a power possessed by all
animals within certain limits, but by the hiber-
nating animal beyond the usual limit.

» See Phil. Trans, for 1832, p. 323.

Sleep, however inscrutable in itself, is the
connecting link between the two physiological
states ; a disquisition on hibernation is, there-
fore, a disquisition on sleep — on profound sleep.
It will shortly appear that one eminent philoso-
pher has fallen into the error of assimilating
different physiological phenomena by neglect-
ing to take this fact into his consideration.
Sleep and hibernation are similar periodical
phenomena, induced by similar causes, leading
to similar effects, and differing only in degree.
Hibernation appears more extraordinary only
because less familiar than sleep. Most animals
are, in fact, naturally awake and asleep every
revolving day, some being diurnal, others noc-
turnal. But in summer the bat actually hiber-
nates, loses its respiration, and with its respira-
tion its temperature, acquires vastly augmented
irritability, and presents the other phenomena
of complete hibernation, regularly and periodi-
cally every twenty-four hours; and the hedge-
hog and the dormouse present similar pheno-
mena, only after other intervals.

Sleep then is the first stage of hibernation.
The faculty of passing into the second is iden-
tical with that of assuming a greatly augmented
irritability of the muscular fibre. Such are the
results of my long attention to this interesting
physiological question. Much error has arisen
from viewing hibernation as a simple effect of
cold. The influence of cold in inducing hiber-
nation is merely its well-known influence in
inducing sleep, concurring with the other causes
of this condition. The direct effect of cold on
the animal frame is, as I shall shortly have
occasion to state particularly, totally different
from hibernation. Hibernation is a physiolo-
gical condition ; the direct effect of cold, or
torpor, is, on the contrary, a pathological and
generally a fatal one.

The term hibernation has usually been ap-
plied to designate what its etymology implies,
the condition in which certain animals pass the
winter season. An error is, as I have already
stated, involved in this view of the subject; for
the condition termed hibernation is not con-
fined to the winter season. Cuvier observes,
in speaking of the Tenrecs, " ce sont. des ani-
maux nocturnes qui passent trois mois de
1'annee en lethargie, quoique habitants de la
zone torride. Burguiere assure meme que c'est
pendant les grandes chaleurs qu'ils dorment."*
Hence the term Sommerschluf employed in Ger-
many. It is plain too, from this circumstance,
that the state of hibernation is not necessarily
connected with a low degree of external tempe-
rature, and we are surprised to find this cele-
brated naturalist, whom I have just quoted,
observing, " la seule condition de la lethargie
est le froid et 1'absence des causes irritantes." f

I must repeat that hibernation is, in every
respect, but the parallel of ordinary sleep, vary-
ing only in force and duration. It is equally
marked by an inexplicable periodicity; it is
equally modified by cooperating or opposing

* Regne Animal, ed. 1829, t. i. p. 125.
t Histoire des Sciences Naturelles, 1829. t. i.
p. 280.

766

HIBERNATION.

causes ; and it is equally manifested in its pe-
culiar effects, only varying in degree and inten-
sity.

In giving a distinct idea of hibernation we
must extend our views to the altered condition
of each function in the animal economy, for
this peculiar state is not limited to any special
function or organ. It is, in fact, a treatise on
physiology which should be written, compa-
ring the state of each function and of each
organ, in the hibernant or lethargic and in the
active condition, a disquisition on sleep, indeed,
in its various degrees, and in its effects in mo-
difying the various functions.

The first question then is, — what is sleep 1 a
question difficult, perhaps impossible, to an-
swer, if we mean by it what is its nature or
essence, but highly interesting to prosecute, if
we mean what are its special phenomena and
their mutual relations.

In order to treat of sleep properly, I must
first observe that, of the nervous system, of
which it is primarily a modification, formerly
divided into the cerebro-spinal and the ganglio-
nic, the first division must now be subdivided
into the cerebral and the true spinal, the former
being the exclusive seat of sensation, volition,
&c. ; the latter, the special source of certain
actions now designated excito-motory, and ob-
served in the orifices, the ingestors, the expul-
sors, the sphincters, &c. Now it is the cere-
bral system which sleeps, the true spinal re-
taining all its energies.

From this enunciation of the primary fact in
sleep, we may trace the whole of the pheno-
mena of this singular condition. In the state
of activity, the cerebral system exerts a peculiar
and continual influence over the true spinal,
which ceases during sleep. In this manner the
functions of the latter appear impaired ; the re-
spiration especially, and with the respiration
the circulation, with which it always maintains
a certain relation, becomes slower, irregular,
and suspended at intervals. These phenomena
observable in ordinary sleep are still more re-
markable in the deep sleep or lethargy of
hibernation or diurnation.

In order that the effects of hibernation may
be traced in relation to all the functions of the
animal economy, I must enter into a few brief
details relative to the arrangement of these
functions and the order in which I propose to
notice them. The most simple and natural
arrangement of the functions appears to me to
be the following : —

I. SANGUIFICATION.

1. The ingestion and) cc ,

2. The digestion.... 5 °f f°°d-

3. The formation.... I «;^^e-

4. Absorption \.f ^y the lacteals.

( 6. by imbibition.

5. The organization of the blood.

II. RESPIRATION.

1. The absorption .. \a' °£oxygen-

{b. of nitrogen, &c.

2. The exhalation . . \f °j>rbonic f^-

( b. of nitrogen, &c.

3. The results

a. augmented temperature.

b. a direct ratio between the
pulsations and respirations.

c. an inverse ratio between
the respiration and irrita-
bility.

III. THE CIRCULATION.

1. The pulmonic.

2. The systemic.

3. The cardiac or coronary.

4. The hepatic.

5. The splenic.

6. The circulation as the ( a. of nutrition.

carrier {b. of temperature.

IV. DEFCECATION.

1. Re-absorption by the lymphatics.

f a. by the lungs.
^ b. by the skin.

2. Excretion s c . by the liver.

i d. by the kidneys.
v e,. by the intestines.

V. THE NERVOUS SYSTEM.

1 . The cerebrai, or the system of

a. The sensations, the senses.

b. Volition, spontaneous motion.

2. The true spinal or excito-motory, or the

system of

a. The orifices.

b. Ingestion.

c. Expulsion.

d. The sphincters.

3. The ganglionic.

VI. THE MUSCULAR SYSTEM.

1 . The irritability.

2. The motility.

I proceed to trace the influence of sleep, and
of the deeper sleep of hibernation upon these
various functions, beginning with the former.

I. Of sleep. — It was first ascertained experi-
mentally by Messrs. Allen and Pepys, that the
quantity of respiration is diminished in ordinary
sleep.* The acts of respiration are obviously
less frequent and less regular, being frequently
suspended for a moment and renewed by a deep
inspiration. The animal frame becomes more
susceptible of the influence of cold. It is most
probable that, during this condition, the irrita-
bility of the muscular system is augmented,
and that this is one of ihejinal objects of sleep;
experiments, however, are still wanting to
establish a fact in reference to ordinary sleep,
which is clearly proved in regard to the sleep
of hibernating animals, and the deeper sleep or
lethargy of hibernation, I shall now proceed
to treat of the sleep of hibernating animals.

II. Of the sleep of hibernating animals. — In
the sleep of the hibernating animal, the respira-
tion is more or less impaired : if the animal be
placed in circumstances which best admit of
observation, the acts of respiration will be
found to have greatly diminished ; if it be
placed in the pneumatometer, little alteration is

* Phil. Trans, for 1809.

HIBERNATION.

767

induced in the bulk of the air; if its tempera-
ture be taken by the thermometer, it will be
found to be many degrees lower than that of
the animal in its active state; if it be deprived
of atmospheric air, it is not immediately in-
commoded or injured.

These facts I have observed in the hedge-
hog,* the dormouse,f and the bat.J If other
authors have not made the same observations,
it is because they have not been aware how
easily this sleep is disturbed. To walk over
the floor, to touch the table, is sufficient, in
many instances, to rouse the animal, to re-pro-
duce respiration, and to frustrate the experi-
ment.

The bat, which is a crepuscular or nocturnal
feeder, regularly passes from its state of activity
to one which may be designated diurnation.
The respiration and the temperature fail; the
necessity for respiration is greatly lessened.

During the summer of 1831, I carefully ob-
served a bat in this condition. If it were quite
quiet, its respiration became very imperfect;
its temperature was but a few degrees above
that of the atmosphere; being placed under
water, it remained during eleven mimites unin-
jured, and on being removed became lively
and continued well.

I have more recently watched the habits of
two hedgehogs, in a temperature varying from
45° to 50°. These animals alternately awake,
take food, and fall asleep. One of them is
frequently awake, whilst the other is dormant,
and goes to sleep at a time that the other
awakes, but without regularity. When awake,
the temperature of each, taken by pressing the
bulb of a thermometer upon the stomach, is
about 95°; when dormant, it is 4.5°; that of
the atmosphere being 42° or 43°. The duration
of this sleep is from two to three days, accord-
ing to the temperature of the atmosphere. On
the 4th of February, 1832, the temperature of
the atmosphere being 50°, both the hedgehogs
were dormant, — the temperature of one was
51°, and that of the other 52°; on the succeed-
ing day, the temperature of the atmosphere had
fallen one degree, the temperature of one of the
hedgehogs was 49°, whilst that of the other,
which had become lively, had risen to 87°; on
the succeeding day, the first had become some-
what lively, and its temperature had risen to
60°, that of the other being 85°, and that of the
atmosphere 47°.

I have observed precisely the same alterna-
tions in the dormouse ; except that this animal
awakes daily in moderate temperatures, takes
its food, and re-passes into a state of sleep, in
which the respiration is greatly impeded, and
the temperature little higher than that of the
atmosphere.

On the day on which the observations were
made on the hedgehogs, the atmosphere being
49°, that of two dormice was 52° ; on the suc-
ceeding day, the external temperature being
47°, that is, lower by two degrees, the tempera-

* Erinaceus Europaens.
t Mvoxus avellanarius.
£ Vespertilio noctula.

ture of one of these dormice was 92°, and that
of the other 94°; and only three hours after-
wards, the temperatures were 60° and 70° re-
spectively, with a slight appearance of lethargy.
The hedgehog and the dormouse appear, in
fact, to awake from the call of hunger, then to
eat, and then again to become dormant, in
temperatures which may be termed moderate.
The bat, which could not find food if it did
awake, does not undergo these periodical
changes, except in the summer season. It ap-
pears to me, from the most careful observation,
that there is every degree between the ordinary
sleep of these animals and the most profound
hibernation.

It is quite obvious, from these observations,
that the ordinary sleep of hibernating animals
differs from that of others, by inducing a more
impaired state of the respiration and of the
evolution of heat, with an augmented power of
bearing the abstraction of the atmospheric air.
This sleep probably passes into true hiberna-
tion, as the blood which circulates through the
brain becomes more and more venous, from
the diminution of the respiration, and as the
muscular fibre of the heart acquires increased
irritability.

It is absolutely necessary, in comparing the
powers of hibernating and other animals, of
evolving heat, accurately to observe whether
there be any tendency to sleep. Mr. Hunter's
and M. Ed wards 's experiments are deficient
for want of this attention. Mr. Hunter, com-
paring the common mouse and the dormouse,
exposed to a very low temperature, observes,
that the temperature of the former was " dimi-
nished 16° at the diaphragm, and 18° in the
pelvis ; while in the dormouse it gained five
degrees, but lost on a repetition." * The ex-
planation of these facts is afforded by the obser-
vation, that when the dormouse increased in
temperature it was " very lively," but that on
the " repetition" it had become " less lively ;"
the mouse was probably in a state of languor
from apprehension or for want of food.

M. Edwards omits to mention whether the
hibernating animals, in his experiments, were
disposed to be lively or dormant, or whether
they had recently recovered from the dormant
state. He does not even mention whether the
experiments on the bat were performed in the
evening, its period of activity, or in the morn-
ing or day, its period of lethargy or diurnation.
Without a particular attention to these points,
no correct result could be obtained. The hiber-
nating animal, in a state of vigour and activity,
is a totally different being from the same animal
disposed to become dormant.

In order to perform this experiment in a
satisfactory manner, the bat, for example,
should be employed in the evening, when it
has naturally awoke from its deep day-slumber,
the hedgehog when it has awoke spontaneously
to take food ; otherwise the disposition to sleep
may explain the loss of temperature. We must
hesitate, therefore, in subscribing to the follow-
ing conclusion of M. Edwards: " Nous voyons

* Animal (Economy, p. 114.

768

HIBERNATION.

que les chauves-souris produisent habituelle-
ment moins de chaleur que les animaux a sang
chaud, et que c'est principalement a cette cause
qu'il faut attribuer 1'abaissement de leur tempe-
rature pendant la saison froide. En comparant
cette experience sur la chauve-souris adulte
avec celles que nous avons faites sur les jeunes
animaux a sang chaud, on y apercoit un rap-
port remarquable ; ils ne produisent pas assez
de chaleur pour soutenir une temperature elevee,
lorsque 1'air est a un degre voisin de zero.
Mais il y a cette difference, que c'est un
etat passager chez les jeunes animaux a sang
chaud, et qu'il est permanent chez les chauves-
souris.

" II est evident que les autres mammiferes
hibernans doivent participer plus ou moins de
cette rnaniere d'etre. Les fails que j'ai exposes
suffisent pour nous faire considerer ce groupe
d'animaux sous le point de vue suivant ; qu'au
printemps et en etc, dans leur etat d'activite et
de veille, lorsque leur temperature est assez
Elevee pour ne pas differer essentiellement de
celle qui caracterise les animaux a sang chaud,
ils n'ont pas la faculte de produire autant de
chaleur; et tout en admettant que d'autres
causes peuvent influer sur leur refroidissement
pendant leur hibernation, il faut cependant
1 'attribuer en grande partie a cette particularite
de leur constitution." *

There are, in fact, these differences between
the young and the hibernating animal: 1. the
former cannot, when exposed alone to severe
cold, maintain its own temperature ; if the lat-
ter appears to be in the same case, it is only
because it has become affected with its peculiar
lethargy ; in its state of wakefulnes>s and activity
it maintains its usual elevated temperature in
the same manner as other adult animals ; 2. the
young animal, in losing its temperature, be-
comes affected, not, like the hibernating animal,
with lethargy, but with torpor, a totally diffe-
rent and a pathological condition which gene-
rally proves fatal. I must conclude these re-
marks by observing that I think the eminent
physiologist whom I have quoted has assimi-
lated the condition of the very young animal
and the adult hibernating animal erroneously.
The mere phenomenon of loss of temperature
is the same ; but the rationale of this pheno-
menon, its causes and its effects, are totally
different.

III. Of perfect hibernation. — I now proceed
to treat of perfect hibernation, of its causes, and
of its effects on the various functions which I
have enumerated. My observations will con-
sist principally of a detail of a series of obser-
vations and experiments made in the course of
the year 1831-1832, compared with the results
obtained by other inquirers.

I consider that there is one special cause of
hibernation, — that law imposed by the Creator,
according to which all animals become affected
with sleep at some period of each revolving
day, and the hibernating animal at some period
of the revolving year. We have thus presented
to us the phenomena of diurnal and nocturnal

* Des A gens Physiques, p. 155.

animals, and the winter-sleep and the summer-
sleep of hibernating animals.

Exposure to cold, not too severe, disposes to
hibernation, as it disposes to ordinary sleep.
Severe cold, on the contrary, first rouses the
hibernating animal from its lethargy, and then
plunges this and all animals into a state of fatal
torpor.

The absence of every kind of stimulus or ex-
citant, and a somewhat confined atmosphere,*
also conduce to hibernation.

Every excitement, on the contrary, that of
hunger, that of the sexes probably, tend to dis-
turb this peculiar lethargy. It is in this man-
ner that we explain the periodicity of sleep and
hibernation, though there is probably also some
hidden influence of the seasons, of the day or
of the year, influences which have been traced
by Dr. Prout and by M. Edwards in regard
to the quantity of respiration.

I now proceed to treat of the condition of the
several functions in hibernation.

The process of sanguification is, in some
hibernating animals, nearly arrested ; in others,
it is entirely so.

There is much difference in the powers of
digestion, and in the fact of omitting to take
food, in the hibernation of different animals.
The bat, being insectivorous, would awake in
vain ; no food could be found : the hedgehog
might obtain snails or worms, if the ground
were not very hard from frost : the dormouse
would find less difficulty in meeting with grain
and fruits. We accordingly observe a remark-
able difference in the habits of awaking from
their lethargy or hibernation, in these different
animals.

I have observed no disposition to awake at all
in the bat, except from external warmth or excite-
ment. If the temperature be about 40° or 45°,
the hedgehog, on the other hand, awakes, after
various intervals of two, three, or four days
passed in lethargy, to take food ; and again re-
turns to its state of hibernation. The dor-
mouse, under similar circumstances, awakes
daily.

Proportionate to the disposition to awake
and take food, is the state of the functions of
the stomach, bowels and kidneys. The dor-
mouse and the hedgehog pass the faeces and
urine in abundance during their intervals of
activity. The bat is scarcely observed to have
any excretions during its continued lethargy.

In the dormouse and the hedgehog, the sense
of hunger appears to rouse the animal from its
hibernation, whilst the food taken conduces to
a return of the state of lethargy. It has already
been observed, that there are alternations be-
tween activity and lethargy in this animal, with
the taking of food, in temperatures about 40°
or 45°. Nevertheless, abstinence doubtless con-
duces to hibernation, by rendering the system

* M. de Saissy observes, " la marmotte, que j'ai
engourdie par deux fois differentes, ne Pa etc, je
crois, que parceque je me suis avise, quand la re-
spiration a ete bien affaiblie, de boucher le trou du
couvercle. Ce n'a ete que de cette maniere que je
suis parvenu a 1'engourdir ; car toutes les tentative
que j'avais faites avant ont etc vaines."

HIBERNATION.

769

more susceptible of the influence of cold, in
inducing sleep and the loss of temperature. The
hedgehog, which awakes from its hibernation,
and does not eat, returns to its lethargy sooner
than the one which is allowed food.

The respiration is very nearly suspended in
hibernation. That this function almost ceases,
is proved, 1st, by the absence of all detectible
respiratory acts ; 2dly, by the almost entire ab-
sence of any change in the air of the pneuma-
tometer; 3dly, by the subsidence of the tem-
perature to that of the atmosphere ; and 4thly,
by the capability of supporting, for a great
length of time, the entire privation of air.

1 . I have adopted various methods to ascer-
tain the entire absence of the acts of respiration.
I placed bats in small boxes, divided by a par-
tition of silk riband, the cover of which con-
sisted of glass, and in the side of which a small
hole was made to admit of placing a long light
rod or feather under the animal's stomach. The
least respiratory movement caused the extremity
of this rod to pass through a considerable space,
so that it became peifectly apparent.

Over the hibernating hedgehog I placed a
similar rod, fixing one extremity near the ani-
mal, and leaving the other to move freely over
an index. During hibernation not the slightest
movements of these rods could be observed,
although they were diligently watched. But
the least touch, the slightest shake immediately
caused the bat to commence the alternate acts
of respiration, whilst it invariably produced the
singular effect of a deep and sonorous inspira-
tion in the hedgehog. It is only necessary to
touch the latter animal to ascertain whether it
be in a state of hibernation or not : in the
former case there is this deep sonorous inspira-
tion; in the latter, the animal merely moves
and coils itself up a little more closely than
before. After the deep inspiration, there are a
few feeble respirations,and then total quiescence.
The bat makes similar respirations without the
deep inspiration, and then relapses into sus-
pended respiration.

2. As the acts of respiration are nearly sus-
pended during hibernation, so are the changes
induced in the atmospheric air.

On January the 28th, the temperature of the
atmosphere being 42°, I placed a bat in the
most perfect state of hibernation and undis-
turbed quiet, in the pneumatometer, during the
whole night, a space of ten hours, from Ih. 30m.
to llh. 30m. There was no perceptible absorp-
tion of gas.

Having roused the animal a little, I replaced
it in the pneumatometer, and continued to dis-
turb it from time to time, by moving the appa-
ratus. It continued inactive, and between the
hours of Ih. iOm. and 4h., there was the absorp-
tion of one cubic inch only of gas.

Being much roused at four o'clock, and re-
placed in the pneumatometer, the bat now con-
tinued moving about incessantly ; in one hour,
five cubic inches of gas had disappeared. It
was then removed. A further absorption took
place of -8 of a cubic inch of gas.

Thus the same little animal, which, in a state
of hibernation, passed ten hours without respi-
ration, absorbed or converted into carbonic acid,

VOL. ii.

5-8 cubic inches of oxygen gas in one hour
when in a state of activity. In an intermediate
condition, it removed one cubic inch of oxygen
in two hours and forty minutes.

I repeated this experiment on February the
18th. A bat, in a state of perfect hibernation,
was placed in the pneumatometer, and remained
in it during the space of twenty-four hours.
There was now the indication of a very slight
absorption of gas, not, however, amounting to
a cubic inch.

On February the 22d, I repeated this expe-
riment once more, continuing it during the
space of sixty hours; the thermometer de-
scended gradually, but irregularly, from 41° to
38°; the result is given in the subjoined table.
External Absorp- Dura-
Date Temperature, tion. tion.
Feb. 22 11 P.M 41°

23 11 A.M 38&.... '8 12h

11 P.M 39| '75 12

24 11 A.M 38 .... *5.... 12

11 P.M 39 '75 12

25 11 A.M 38 "6 12

3-4

60

From this experiment it appears that 3*4
cubic inches of oxygen gas disappeared in sixty
hours, from the respiration of a bat in the state
of lethargy. It has been seen that in a state of
activity, an equal quantity of this gas disap-
peared in less than half that number of minutes.
The respiration of the hibernating bat descends
to a sub-reptile state ; it will be seen shortly
that the irritability of the heart and of the mus-
cular fibre generally, is proportionably aug-
mented.

In this experiment it is probable that the
lethargy of the animal was not quite complete.
Should the temperature of the atmosphere fall,
and continue at 32°, I shall again repeat it
under these circumstances. The respiration
will probably be still more nearly suspended.

It is important to remark, that the registra-
tion of the quantity of absorption in these expe-
riments was not begun until several hours after
the animal had been inclosed within the jar of
the pneumatometer, so that the absorption of
the carbonic acid always present in atmospheric
air was excluded from the result.

It may be a question whether the slight
quantity of respiration I have mentioned be
cutaneous. The absence of the acts of respira-
tion would lead us to this opinion. But it may
be observed, that these acts have not been
watched, and can scarcely be watched continu-
ously enough, to determine the question of
their entire absence. Some contrivance to as-
certain whether the rod has moved along the
index during the absence of the observer would
resolve every doubt upon this interesting point.
And I think it right to remark, that after the
apparent total cessation of respiration, as ob-
served by the means which have just been de-
scribed, there is probably still a slight diaphrag-
matic breathing. I am led to this conclusion,
by having observed a slight movement of the
flank in a favourable light, unattended by any
motion of the thorax or epigastrium.

3. Much precaution is required in ascertam-
3 E

770

HIBERNATION.

ing the comparative temperature of the animal
with that of the atmosphere. The slightest ex-
citement induces a degree of respiration, with
the consequent evolution of heat.

The plan which is best adapted to determine
this question in regard to the bat, and which I
have adopted, together with every attention to
preserve the animal quiet and undisturbed, is
the following : a box was made of mahogany,
with a glass lid, divided horizontally at its mid-
dle part, by a fold of strong riband, and of

such dimensions as just to contain the animal.
The bat was placed upon the riband, and in-
closed by fixing the lid in its place. Being
lethargic, it remained in undisturbed quiet. A
thermometer, with a cylindrical bulb, was now
passed through an orifice made in the box on a
level with the riband, under the epigastrium of
the animal, and left in this situation. This
arrangement is made obvious by the subjoined
wood-cut, (jig. 306,) which also displays the
mode of examining the circulation.

306.

It was only now necessary to make daily ob-
servations and comparisons between this ther-
mometer and another placed in the adjacent at-
mospheric air. The layer of silk, and the por-
tion of air underneath, protected the animal
from the immediate influence of the tempera-
ture of the table, on which the box was placed.

The following table gives the result of obser-
vations made during many days, in very vary-
ing temperatures.

Temperature of Temperature
Date. the Atmosphere, of the Animal.

Jan. 6 11 P.M 40 ..&|

7 8 P.M 43 -.43

8 .41 41£

9 11 P.M 47 46

10 10 A.M 46 46

— 12 midnight.. 47 47

11 10 P.M 45 45

12 11 P.M 45 45

13 11 P.M. 37 37£

14 11 A.M 37 37

— 11 P.M 40 40

15 2 P.M 37 37

— 11 P.M 35 35

16 11 P.M 37 37

17 11 P.M 42 42

18 11 A.M 40 40

19 10 P.M 36 36

20 11 P.M 39 39

21 11 P.M 40 40

22 11 P.M 44 44

23 10 A.M 42$ 42£

— 11 P.M 40§ 40|

24 11 P.M 43& 43£

25 10 P.M 42 42

26 10 P.M 41 41

27 10 P.M 37 37

28 11 A.M 34§ 34f

— 11 P.M 37 37

29 11 A.M 42 42

11 P.M 43 43

30 11 P.M 42 42

31 11 P.M 39§ 39|

From this table it is obvious that the tempe-
rature of the hibernating animal accurately fol-
lows that of the atmosphere. When the changes
of temperature in the latter are slight, the two
thermometers denote the same temperature. If
these changes are greater and more rapid, the
temperature of the animal is a little lower or
higher, according as the external temperature
rises or falls ; a little time being obviously re-
quired for the animal to attain that temperature.

Similar observations were made during the
first three days of February. On the 4th, how-
ever, the temperature of the atmosphere rose to
50£°; that of the animal was now 82°, and there
was considerable restlessness. On the 6th, the
temperature of the, atmosphere had fallen to
47$ , and that of the animal to 48°, whilst there
was a return of the lethargy.

After this period there were the same equal
alterations of temperature in the animal and in
the atmosphere, observed in the month of
January.

It is only necessary to add to these observa-
tions, that the internal temperature is about
three degrees higher than that of the epigas-
trium. In two bats, the external temperature
of each of which was 36°, a fine thermometer,
with an extremely minute cylindrical bulb,
passed gently into the stomach, rose to 39°.

The following experiments, made by the
celebrated Jenner, illustrate this point :

" In the winter, the atmosphere at 44°, the
heat of a torpid hedgehog at the pelvis was 45°,
and at the diaphragm 48£°.

" The atmosphere 26°, the heat of a torpid
hedgehog, in the cavity of the abdomen, was
reduced so low as 30°.

" The same hedgehog was exposed to the
cold atmosphere of 26° for two days, and the
heat of the rectum was found to be 93°; the
wound in the abdomen being so small that it
would not admit the thermometer.*

* The animal had become lively. See Hunter
on the Animal (Economy, p. 1 13.

HIBERNATION.

771

" A comparative experiment was made with
a puppy, the atmosphere at 50°; the heat in
the pelvis, as also at the diaphragm, was 102°.

" In summer, the atmosphere at 78°, the
heat of the hedgehog, in an active state in the
cavity of the abdomen, towards the pelvis, was
95° ; at the diaphragm, 97°." *

There is an error in the admirable work of
M . Edwards, as I have already stated, in rela-
tion to the present subject, which it is important
to point out. 3VI. Edwards first ascertained the
interesting fact, that the very young of those
species of animals which are born blind, lose
their temperature if removed from the contact
of their parent ; and justly concludes that they
have not sufficient power of evolving heat, to
maintain their natural temperature when so ex-
posed. M. Edwards then subjected hiberna-
ting animals to the action of cold, and observ-
ing that their temperature also fell, he concludes
that they, like the very young animal, have not
the faculty of maintaining their temperature
under ordinary circumstances.f

It is remarkable that this acute physiologist
did not perceive the error in this reasoning. In
no instance does the young animal maintain its
warmth, when exposed alone to the influence
of an atmosphere of moderate temperature.
Can this be said of the hibernating animal ?
Certainly not. In ordinary temperatures, the
hibernating animal maintains its activity, and
with its activity, its temperature. The loss of
temperature in this kind of animal is an in-
duced condition, occasioned by sleep.

There is a point unnoticed in M. Edwards's
experiment. It is the condition of the bat in
regard to activity or lethargy under the exposure
to cold ; and upon this the whole phenomena
depend.

The differences between the young animal
benumbed, and the hibernating animal lethargic,
from cold, are both great and numerous. I
purpose to point them out particularly on a
future occasion.

4. It is in strict accordance with these facts,
that the lethargic animal is enabled to bear the
total abstraction of atmospheric air or oxygen
gas, for a considerable period of time.

Spallanzani placed a marmot in carbonic acid
gas, and makes the following report of the ex-
periment in a letter to Senebier : " Vous vous
ressouviendrez de ma marmotte qui fut si forte-
ment lethargique dans 1'hiver severe de 1795 ;
je la tins alors pendant quatre heures dans le
gaz acide carbonique, le thermometre marquant
— 12°, elle continua de vivre dans ce gaz qui
est le plus mortel de tous, comme je vous le
disais : au moins un rat et un oiseau que j'y
placai avec elle y perirent a 1'instant meme. II
parait done que sa respiration fut suspendue
pendant tout ce terns-la. Je soumis a la meme
experience des chauve-souris semblablement
iethargiques, et le resultat fut le meme." I

* Ibid. p. 112.

t Des A gens Physiques, p. 155.

$ Memoires sur la Respiration, par Lazare Spal-
lanzani, traduites en Fran9ais, d'apres son manu-
«crit inedit, par Jean Senebier, p. 75.

A bat which was lethargic in an atmosphere
of 36° was immersed in water of 41°. It moved
about a little, and expelled bubbles of air from
its lungs. It was kept in the water during six-
teen minutes, and then removed. It appeared
to be uninjured by the experiment.

A hedgehog which had been so lethargic in
an atmosphere of 40° as not to awake for food
during several days, was immersed in water of
42°. It moved about and expelled air from its
lungs. It was retained under the water during
22 £ minutes. It was then removed. It ap-
peared uninjured.

It seems probable that the motions observed
in these animals were excited through the me-
dium of the cutaneous nerves.

The power of supporting the abstraction of
oxygen gas, or atmospheric air, belongs solely
to the hibernating state, and is no property of
the hibernating animal in its state of activity.
After having found that the dormant bat, in
summer, supported immersion in water during
eleven minutes, uninjured, I was anxious to
know whether the active hedgehog possessed
the same power. I immersed one of these ani-
mals in water. It expired in three minutes,
the period in which immersion proves fatal to
the other mammalia. Sir Anthony Carlisle
has. therefore, committed an error, somewhat
similar to that of M. Edwards, when he asserts
that " animals of the class Mammalia, which
hibernate and become torpid in winter, have at
all times a power of subsisting under a confined
respiration, which would destroy other animals
not having this peculiar habit." * The power
of bearing a suspended respiration is an in-
duced state. It depends upon sleep or lethargy
themselves, and their effect in impairing or sus-
pending respiration; and upon the peculiar
power of the left side of the heart, of becoming
veno-contractile under these circumstances.

The circulation is reduced to an extreme de-
gree of slowness, according to a law well-
known, but hitherto, I believe, unexplained,
according to which the respiration and the cir-
culation are always proportionate to each other.

The wing of the bat affords an admirable op-
portunity of observing the condition of the cir-
culation during hibernation. But it requires
peculiar management. If the animal be taken
from its cage, and the wing extended under the
microscope, it is roused by the operation, and
its respiratory and other movements are so ex-
cited, that all accurate observation of the condi-
tion of the circulation in the minute vessels is
completely frustrated. Still greater caution is
required in this case than even in the observa-
tion of the respiration and temperature.

After some fruitless trials, I at length suc-
ceeded perfectly in obtaining a view of the mi-
nute circulation undisturbed. Having placed
the animal in its state of hibernation, in a little
box of mahogany, I gently drew out its wing
through a crevice made in the side of the lx>x ;
I fixed the tip of the extended wing between
portions of cork ; I then attached the box and
the cork to a piece of plate-glass ; and lastly, I

* Phil. Trans. 1805, p. 17.

3 E 2

772

HIBERNATION.

left the animal in this situation, in a cold atmo-
sphere, to resume its lethargy. (See Jig. 306.)

I could now quietly convey the animal ready
prepared, and place it in the field of the micro-
scrope without disturbing its slumbers, and
observe the condition of the circulation.

In this manner 1 have ascertained that,
although the respiration be suspended, the cir-
culation continues uninterruptedly. It is slow
in the minute arteries and veins ; the beat of
the heart is regular, and generally about twenty-
eight times in the minute.

We might be disposed to view the condition
of the circulation in the state of hibernation as
being reptile, or analogous to that of the batra-
chian tribes. But when we reflect that the re-
spiration is nearly, if not totally, suspended,
and that the blood is venous,* we must view
the condition of the circulation as in a lower
condition still, and, as it were, sub-reptile. It
may, indeed, be rather compared to that state of
the circulation which is observed in the frog from
which the brain and spinal marrow have been
removed by minute portions at distant inter-
vals, f

In fact, in the midst of a suspended respira-
tion, and an impaired condition of some other
functions, one vital property is augmented.
This is the irritability, and especially the irrita-
bility of the left side of the heart. The left
side of the heart, which is, in the hibernating
animal, in its state of activity, as in all the
other mammalia, only arterio-contractile, be-
comes veno-contractile.

This phenomenon is one of the most remark-
able presented to me in the whole animal king-
dom. It forms the single exception to the
most general rule amongst animals which pos-
sess a double heart. It accounts for the possi-
bility of immersion in water or a noxious gas,
without drowning or asphyxia ; and it accounts
for the possibility of a suspended respiration,
without the feeling of oppression or pain,
although sensation be unimpaired. It is, in a
word, this peculiar phenomenon, which, con-
joined with the peculiar effect of sleep in in-
ducing diminished respiration in hibernating
animals, constitutes the susceptibility and capa-
bility of taking on the hibernating state. On
the other hand, as the rapid circulation of a
highly arterialized blood in the brain and spinal
marrow of birds probably conduces to their
activity, the slow circulation of a venous blood
doubtless contributes to the lethargy of the
hibernating animal.

I need scarcely advert to the function of
defecation. It has already been briefly noticed
under the head of sanguification, with which it
proceeds pari passu.

Iff regard to the nervous system, I can only
repeat that sensation and volition are quiescent.

* M. Prunelle observes, " En comparant le sang
de deux chauve-souris auxquelles j'avois ouvert les
carotides, a Tune pendant son engonrdissement et
a 1'autre dans Tetat de veille, j'ai trouve celui de
la derniere beaucoup plus vermeil." Annales du
Museum, tome xviii. p. 28.

t Essay on the Circulation, pp. 136-141.

In my memoir upon the subject of hibernation,*
1 committed an error relative to this subject.
But I am now satisfied that what I considered
to be evidences of an unimpaired sensibility,
were phenomena of the excito-motorykind. Thus
I have observed that the slighest touch applied
to one of the spines of the hedgehog immedi-
ately rouses it to draw that deep inspiration of
which I have spoken. The merest shake in-
duces a few respirations in the bat. The least
disturbance, in fact, is felt, as is obvious from
its effect in inducing motion in the animal.

It is from the misconception on this point
that the error has arisen, that the respiration is
not absolutely suspended in hibernation. This
function has been so readily re-excited, that it
has been considered as appertaining to the state
of hibernation.

As I have already stated, the cerebral func-
tions sleep, the true spinal functions retain their
wonted energy ; and if the respiration be nearly
suspended, it is because little carbonic acid, the
excitor of respiration, is evolved.

In the midst of a suspended or partially sus-
pended respiration, the irritability of the mus-
cular fibre becomes proportionately augmented.

The single fact of a power of sustaining the
privation of air, without loss of life, leads alone
to the inference that the irritability is greatly
augmented in the state of hibernation. This
inference flows from the law already stated,
and the fact is one of its most remarkable illus-
trations and confirmations.

It might have been inferred from these pre-
mises, that the beat of the heart would continue
longer after decapitation in the state of hiber-
nation than in the state of activity in the same
animal ; an inference at once most singular and
correct.

This view receives the fullest confirmation
from the following remarkable experiment : on
March the 9th, soon after midnight, I took a
hedgehog which had been in a state of uninter-
rupted lethargy during 150 hours, and divided
the spinal marrow just below the occiput; I
then removed the brain and destroyed the
whole spinal marrow as gently as possible.
The action of the heart continued vigorous
during four hours, when, seeing no prospect of
a termination to the experiment, I resolved to
envelope the animal in a wet cloth, and leave
it until early in the morning. At 7 o'clock
A.M. the beat of both sides of the heart still
continued. They still continued to move at
10 A.M., each auricle and each ventricle con-
tracting quite distinctly. At half-after 1 1 A.M.
all were equally motionless ; yet all equally
contracted on being stimulated by the point of
a penknife. At noon the two ventricles were
alike unmoved on being irritated as before; but
both auricles contracted. Both auricles and
ventricles were shortly afterwards unirritable.

This experiment is the most extraordinary of
those which have been performed upon the
mammalia. It proves several interesting and
important points : 1. That the irritability of the
heart is augmented in continued lethargy in an

* Phil. Trans, for 1832.

HIBERNATION.

773

extraordinary degree. 2. That the irritability
of the left side of the heart is then little, if at
all, less irritable than the right, — that it is, in
fact, veno-contractile. 3. That, in thre condi-
tion of the animal system, the action of the
heart continues for a considerable period inde-
pendently of the brain and spinal marrow.

On April the 20th, at six o'clock in the even-
ing, the temperature of the atmosphere being
53°, a comparative experiment was made upon
a hedgehog in its state of activity : the spinal
marrow was simply divided at the occiput; the
beat of the right ventricle continued upwards
of two hours, that of the left ventricle ceased
almost immediately ; the left auricle ceased to
beat in less than a quarter of an hour; the right
auricle also ceased to beat long before the right
ventricle.

In further proof of the same fact, I may here
adduce a remarkable paragraph from the paper
of Mangili in the Annales du Museum:*
" J'observai a peu pres les memes choses dans
une autre marmotte en lethargie, que je deca-
pitai le 22 de Mars 1807. Mais en ouvrant
celle-ci, j'avois deux objets : le premier, d'ex-
aminer 1'etat des visceres les plus importans,
comnae le coeur, les poumons et le cerveau. Le
second etoit de voir comment precedent les
phenomenes de 1'irritabilite musculaire ; parce
qu'ayant entendu dire a un celebre naturaliste,
que 1'engourdissement avoit pour cause 1'altera-
tion ou la suspension de cette irritabilite, il
m'importoit de savoir si cette assertion etoit
vraie. Dans la chambre ou se trouvoit la mar-
motte, le thermometre etoit a 6 degres et demi :
1'ayant introduit dans le bas ventre, il monta
d'un degre, c'est-a-dire a 7 degres et demi.

" Je trouvai les poumons dans leur etat na-
turel. Le cceur continua a battre pendant plus
de trois heures. Les pulsations, d'abord vives
et frequentes, s'aflfoiblirent et se ralentirent peu-
a-peu. J'en avois compte de seize a dix-huit
par minute au commencement de la premiere
heure ; a la fin de la troisieme je n'en comptois
plus que trois dans le meme temps. Les
veines du cerveau me parurent gonflees de
sang.

" La tele unie au cou ayant etc separee du
tronc, je la mis dans un vase avec de 1'esprit-
de-vin, et j'y remarquai, meme apres une derni-
heure, des mouvemens assez sensibles. Ce fait
prouve, ainsi que plusieurs autres dont je par-
lerai bientot, que si dans 1'etat de lethargie
conservatrice la vie est beaucoup moins ener-
gique, le principe vital repandu dans les diver-
ses parties, a beaucoup plus de tenacite, et
tarde bien plus a s'eteindre.

" Je separai du corps de 1'animal plusieurs
morceaux des muscles qui obeissent a la vo-
lonte, et je vis avec etonnement que, trois
heures apres la mort, ils se contractoient forte-
ment chaque fois que je les soumettois a 1'ac-
tion galvanique. Ces mouvemens convulsifs
ne se ralentirent qu'au bout de quatre heures.

" II suit de la que les marmottes tuees pen-
dant qu'elles sont en lethargie, presentent, rela-
tivemeut a 1'irritabilite, a peu pres les memes

* Tome x. p. 453-456.

phenomenes qu'on remarque dans plusieurs
animaux a sang fro id.

" Pour savoir ensuite si les phenomenes d'ir-
ritabilite etoient les memes dans 1'etat de veille
et dans celui de lethargie, le 25 de Juin, j'ai
fait perir, precisement de la meme maniere,
une seconde marmotte qui etoit eveillee depuis
deux mois, et qui faisoit de frequentes courses
dans le jardin. Mon thermometre marquoit
ce jour-la 18 degres: 1'ayant introduit dans le
ventre de la marmotte au moment ou je venois
de la decapiter, il s'eleva a 29 degres.

" Ayant mis le cffiur a decouvert, comme je
1'avois fait dans mon experience du mois de
Mars, je comptai d'abord vingt-sept ou vingt-
huit pulsations par minute. Ce nombre n 'etoit
plus que de douze au bout d'un quart d'heure,
et de huit, au bout de demi-heure : dans le dix
minutes suivantes, il n'y cut plus que quatre
pulsations tres-foibles par minute, et elles ces-
serent totalement dans les dix dernieres minutes,
c'est-a-dire cinquante minutes apres la mort de
1'animal; tandis que le coeur de la marmotte
tuee dans 1'etat de lethargie, donnoit encore
quatre legeres pulsations par minute, trois
heures apres que la tete avoit ete separee du
corps. Cette grande difference prouve que le
principe de 1'irritabilite s'accumule pendant la
lethargie conservatrice.

" Les chairs musculaires me semblirent plus
pales que celles de la marmotte en lethargie :
elles etoient d'abord tres sensibles a 1'action
galvanique; mais ses signes d'irritabilite s'affoi-
blirent et disparurent bien plus rapidement.
En effet, les chairs musculaires de cette mar-
motte etoient peu sensibles au bout de deux
heures, tandis que dans la marraotte tuee en
hiver elles se contractoient fortement au bout
de trois heures, et que 1'irritabilite ne s'affoiblit
notablement que quatre heures apres la mort.

" Les chairs des muscles intercostaux et
abdominaux conserverent leur sensibilite au
stimulus electrique quelques minutes de plus
que celles des membres ; d'oii Ton peut con-
clure que le principe de 1'irritabilite se conserve
d'avantage dans certaines parties du merae ani-
mal. Mais ce qui est prouve jusqu'a 1'evidence,
c'est que ce principe a bien plus de tenacite
dans les chairs de 1'animal tue pendant 1'etat
de lethargic, que dans celles de 1'animal tu6
pendant 1'etat de veille."

This author does not appear to have had any
apprehension of the extreme importance of this
extraordinary change in the irritability, but
merely states it as a fact. Its due value can
only be known by observing the dependence of
the functions of life on that law of the inverse
condition of the respiration and of the irritabi-
lity, of which so much has already been said.
In the hibernating animal the respiration is
nearly suspended ; had not the irritability be-
come proportionately augmented, the actions of
life must have ceased !

I must add one remark upon the motility of
the muscular fibre in hibernation ; it is unim-
paired. Those physiologists who have asserted
the contrary, have, as will be shown shortly,
mistaken the phenomena of torpor from cold,
for those of true hibernation.

774

HIBERNATION.

If the hedgehog in a state of the most perfect
lethargy, uncomplicated with torpor, be touched,
its respiration is resumed, and it coils itself up
more forcibly than before. The dormouse, in
similar circumstances, unfolds itself; and the
bat moves variously. Not the slightest stiffness
is observed. The hedgehog, when roused, walks
about, and does not stagger, as has been asserted.
The bat speedily takes to the wing, and flies
about with great activity, although exhaustion
and death may subsequently result from the
experiment. The phenomena are similar to
those of awaking from natural sleep. Impaired
motility, stiffness, lameness, &c. belong to tor-
por, and not to true hibernation.

III. Of reviviscence. — Not the least inte-
resting of the phenomena connected with hiber-
nation are those of reviviscence. Hibernation
induces a state of irritability of the left side of
the heart, which, with high respiration and an
arterialized blood, would be incompatible with
life. Respiration suddenly restored, and per-
manently excited, is, therefore, as destructive as
its privation in other circumstances.

All those bats which were sent to me from
distant parts of the country died. The conti-
nued excitement from the motion of the coach
keeping them in a state of respiration, the ani-
mal perished. One bat had, on its arrival,
been roused so as to fly about. Being left
quiet, it relapsed into a state of hibernation.
The excitement being again repeated the next
day, it again flew about the room ; on the suc-
ceeding day it was found dead.

It is in accordance with this law, that we
observe hibernating animals adopting various
measures to secure themselves from frequent
sources of disturbance and excitement. They
choose sheltered situations, as caverns, burrows,
&c. secure from the rapid changes and the in-
clemencies of the weather and season. Many
form themselves nests ; others congregate toge-
ther. The hedgehog and the dormouse roll
themselves up into a ball. The common bat
suspends itself by the claws of its hinder feet,
with its head dependent, generally in clusters ;
the horseshoe bat (ferrum equinum) spreads its
wings so as to embrace and protect its fellows.

All these circumstances are obviously de-
signed to prevent disturbed hibernation.

In the depth of caverns, and other situations
sheltered from changes of temperature in the
atmosphere, the calls of hunger are probably
the principal cause of reviviscence in the spring.
The other causes of reviviscence are the return
of warmth and external excitements : it is inte-
resting to observe and trace the gradual return
of respiration in the former case, and of the
temperature of the animal in the latter.

If the hibernating hedgehog be touched even
very gently, it draws a deep breath, and then
continues to breathe for a short time. If this
excitement be repeated, the animal is perma-
nently roused, and its temperature raised. If
the temperature of the atmosphere be augment-
ed, the respiration is gradually excited, and the
animal is gradually restored to its state of
activity.

If a hibernating animal be excited in a very

cold atmosphere, its temperature rises variously,
and then falls. A bat was perfectly lethargic
in a temperature of 36°. A fine thermometer,
with a cylindrical bulb, was introduced into its
stomach; it rose to 39°. One hour after-
wards, the animal not being further disturbed,
the respiration was rapid, and the temperature
in the stomach 93°. Shortly afterwards the
temperature was 90°. The minute circulation
was pretty good, and pulsatory in the arteries,
the heart beating from twenty-eight to thirty-
six times in the minute.

In another bat, in an atmosphere of the tem-
perature of 36°, the thermometer in the stomach
rose to 39°. The animal being continually ex-
cited, the temperature rose to 65°, but speedily
fell to 60°.

The animal excited and revived in this man-
ner is in a state of exhaustion and inanition. It
is incapable of maintaining its temperature if
exposed to cold, and will die unless it repass
into the state of hibernation. It may be com-
pared to the case of the mouse deprived of food
in the following experiment of Mr. Hunter.
" A mouse was put into a cold atmosphere of
13° for an hour, and then the thermometer was
introduced as before ; but the animal had lost
heat, for the quicksilver at the diaphragm was
carried only to 83°, in the pelvis to 78°.

" In order to determine whether an animal
that is awakened has the same powers, with
respect to preserving heat and cold, as one that
is vigorous and strong, I weakened a mouse by
fasting, and then introduced the bulb of the
thermometer into its belly ; the bulb being at
the diaphragm, the quicksilver rose to 97° ; in
the pelvis to 95°, being two degrees colder than
the strong mouse : the mouse being put into
an atmosphere as cold as the other, and the
thermometer again introduced, the quicksilver
stood at 79° at the diaphragm, and at 74° in
the pelvis.

" In this experiment the heat at the dia-
phragm was diminished 18°, in the pelvis 21°.

" This greater diminution of heat in the
second than in the first, we may suppose pro-
portional to the decreased power of the animal,
arising from want of food.' *

But extreme cold alone, by a painful effect
induced on the sentient nerves, rouses the
hibernating animal from its lethargy, as has
been remarked already, and is illustrated by the
following experiments of Hunter. " Having
brought a healthy dormouse, which had been
asleep from the coldness of the atmosphere,
into a room in which there was a fire, (the
atmosphere at 64°,) I introduced the thermo-
meter into its belly, nearly at the middle, be-
tween the thorax and pubis, and the quicksilver
rose to 74° or 75° ; turning the bulb towards
the diaphragm, it rose to 80° ; and when I ap-
plied it to the liver, it rose to 81 §°.

" The mouse being placed in an atmosphere
at 20°, and left there half an hour, when taken
out was very lively, even much more so than
when put in. Introducing the thermometer
into the lower part of the belly, the quicksilver

* Animal (Economy, pp. 114, 115.

HIBERNATION.

775

rose to 91°; and turning it up to the liver, to
93°.

" The animal being replaced in the cold
atmosphere at 30°, for an hour, the thermome-
ter was again introduced into the belly ; at the
liver it rose to 93°; in the pelvis to 92°; the
mouse continuing very lively.

" It was again put back into an atmosphere
cooled to 19°, and left there an hour; the ther-
mometer at the diaphragm was 87°; in the
pelvis 83°; but the animal was now less
lively.

" Having been put into its cage, the thermo-
meter being placed at the diaphragm, in two
hours afterwards was at 93°." *

In these experiments the animals appear to
have been roused partly by the state of the
wound in the abdomen, but chiefly by the ex-
treme cold. They can scarcely, however, be
considered as experiments upon hibernation,
however interesting they may be in reference to
reviviscence from that state.

The fact of the fatal influence of excited re-
spiration during the augmented irritability of
hibernation, contrasted with the similar fatal
effect of suspended respiration, during the dimi-
nished irritability of the state of activity, will
illustrate many of the causes, kinds, and phe-
nomena of death. Do not these resolve them-
selves, in fact, into irritability insufficiently or
excessively excited ?

IV. Of torpor from cold. — It is highly im-
portant, and essential to the present investiga-
tion to distinguish that kind of torpor which
may be produced by cold in any animal, from
true hibernation, which is a property peculiar
to a few species. The former is attended by a
benumbed state of the sentient nerves, and a
stiffened condition of the muscles ; it is the
direct and immediate effect of cold, and even
in the hibernating animal is of an injurious and
fatal tendency; in the latter, the sensibility and
raotility are unimpaired, the phenomena are
produced through the medium of sleep ; and
the effect and object are the preservation of
life.

Striking as these differences are, it is certain
that the distinction has not always been made
by former observers. In all the experiments
which have been made, with artificial tempera-
tures especially, it is obvious that this distinc-
tion has been neglected.

True hibernation is induced by temperatures
only moderately low. All hibernating animals
avoid exposure to extreme cold. They seek
some secure retreat, make themselves nests or
burrows, or congregate in clusters, and, if the
season prove unusually severe, or if their retreat
be not well chosen and they be exposed in con-
sequence to excessive cold, many become be-
numbed, stiffen, and die.

In our experiments upon hibernation we
should imitate nature's operations. Would any
one imagine that the following detail contained
the account of an experiment upon this sub-
ject ? " Le 31 Janvier," says M. Saissy, " a
trois heures du soir, la temperature atmosphe-

* Animal (Economy, pp. Ill, 112.

rique etant a l°-25 au-dessous de zero, celle
d'un herisson engourdi profondement a 3°'50
au dessus, j'enfermai ce quadrupede dans un
bocal de verre entoure de toute part d'une mix-
tion de glace et de muriate de soude. L'exces
du froid le reveilla d'abord, mais trois heures
ont suffi pour le replonger dans une profonde
torpeur.

" J'avais place 1'animal de rnaniere que je
pouvais repeter, autant que je le jugeais neces-
saire, les experiences thermometriques. Des
que sa temperature cut baisse jusqu'a zero, (ce
ne fut qu'a 2 heures du matin) je le retirai du
bocal et le placai dans une temperature de 12°
et plus au dessus de la glace ; mais 1'animal
e"tait mort." *

To induce true hibernation, it is quite neces-
sary to avoid extreme cold ; otherwise we pro-
duce the benumbed and stiffened condition to
which the term torpor or torpidity may be
applied. I have even observed that methods
which secure moderation in temperature, lead
to hibernation : hedgehogs, supplied with hay
or straw, and dormice, supplied with cotton-
wool, make themselves nests and become lethar-
gic ; when others, to which these materials are
denied, and which are consequently more ex-
posed to the cold, remain in a slate of activity.
In these cases, warmth or moderated cold ac-
tually concur to produce hibernation.

When we read of insensibility, of a stiffened
state of the muscles, and of a cessation of the
circulation, as obtaining in hibernation, we may
be certain that a state of torpor has been mis-
taken for that condition. The actually hiber-
nating animal exposed to continued severe cold
is, as M. Saissy correctly observes, first roused
from this state of ease and preservation into a
painful activity, and then plunged into a fatal
torpor.

This subject will come to be considered in a
subsequent part of this inquiry, in which I
purpose to trace the effects of cold in changing
the relative quantity of respiration and degree
of the irritability in animals of different ages
which do not hibernate ; in the meantime, the
accurate distinction between mere torpor, which
may occur in any animal, and which is a de-
structivestate, from true hibernation, which is
preservative, and the peculiarity of certain ani-
mals, will enable us to correct many inaccuracies
into which Legallois,f M. Edwards,^ and other
physiologists have fallen. (See IRRITABILITY.)

In conclusion, one of the most general effects
of sleep is to impair the respiration, and with
that function the evolution of animal tempera-
ture. The impaired state of the respiration in-
duces a less arterial condition of the blood,
which then becomes unfit for stimulating the
heart; accumulation of the blood takes place
in the pulmonary veins and left auricle ; a
sense of oppression is induced, and the animal
is either roused to draw a deep sigh or awakes
altogether.

* Recherches stir les Animaux hibernans, par
M. J. A. Saissy, pp. 13, 14.

f (Euvres de Lcgallois, Paris, 1824, p. 282.
f Agens Physiques, pp. 148, 292.

776

NORMAL ANATOMY OF THE HIP-JOINT.

Such are the phenomena in animals in which
the heart has not the faculty of taking on an
augmented state of irritability, with this lessened
degree of stimulus. But in those animals which
do possess this faculty, a property which con-
stitutes the power of hibernation, the heart con-
tinues the circulation of the blood, more slowly
indeed, but not less perfectly, although its arte-
rial character be diminished and its stimulant
property impaired. No repletion of the pul-
monary veins and of the left auricle, no sense
of oppression is induced, and the animal is not
roused ; the respiration continues low, the tem-
perature falls, and the animal can bear, for a
short period, the abstraction of atmospheric air.

All the phenomena of hibernation originate,
then, in the susceptibility of augmented irritabi-
lity. The state of sleep, which may be viewed
as the first stage of hibernation, induces an im-
paired degree of respiration. This would soon
be attended with pain, if the irritability of the
heart were not at the same time augmented, so
as to carry on the circulation of a less arterial
blood, and the animal would draw a deep sigh
— would augment its respiration or awake.
Occasional sighs are, indeed, observed in the
sleep of all animals, except the hibernating. In
these, the circulation goes on uninterruptedly,
with a diminished respiration, by the means of
an augmented irritability. There is no stagna-
tion of the blood at the heart ; consequently, no
uneasiness; and the animal becomes more and
more lethargic, as the circulation of a venous
blood is more complete. This lethargy is even-
tually interrupted by circumstances which break
ordinary sleep, as external stimuli or the calls
of appetite.

It still remains for me briefly to discuss the
question, — what are the hibernating animals?
1 must first advert to the fact, on which I have
already insisted, that hibernation does not pre-
sent itself in an equal degree in all the hiber-
nating tribes. All animals sleep periodically,
in the night or in the day. Some sleep for
several days together, especially after taking
food, and in the cool seasons of the year, as the
hedgehog. Perhaps the bat may be the only
animal which sleeps profoundly the winter
through, without awaking to take food.

These remarks prepare us for a more just
view of hibernation and of hibernating animals
than is, as I believe, usually taken.

Of the hibernating animals the most unequi-
vocal are the bat, the hedgehog, the marmot,
the hamster, the dormouse. It has been said
that the bear and beaver belong to the num-
ber, but this is extremely doubtful. It has
been said also that the swallow belongs to the
hibernating class, but this is incorrect. The
cold-blooded animals, the Chelonian, the Sau-
rian, the Ophidian, and the Batrachian tribes,
all, however, indubitably pass the winter in a
state of apathy and lethargy. Some of the
fishes also become lethargic during the cold
season. The same remark applies to some of
the molluscous and insect tribes.

BIBLIOGRAPHY. -//Mw/er, An. (Economy, Owen's
edition, p. 131. Lond. 1837. Spallansani, Mem.

sur la Respiration, par Senebier. Gcnev. 1803 ;
or Eng. translat. Edinb. 1804. De Saissy, Re-
cherchesexp. sur les Anim.Hivernans., Lyons, 1808.
Mangili, Essai sur la Lethargie periodique. Milan,
1807. Edwards, snr les Aa;ens Physiques. Paris,
1824, or Dr. Hodgkin's English transl. Prunelle,
Recherchcs sur les phenom. et sur les causes du
sommeil hivernal. Ann. du Mus. t. xviii. Bertfiold,
Miiller's Archiv. 1837, p. 67. MUller's Physiology,
passim.

(Marshall Hall.)

HIP-JOINT, NORMAL ANATOMY
OF (in human anatomy). — Fr. articulation
ilio-femorale ; Germ. Huft gelenk. — This joint
belongs to the class of enarthrodial or ball and
socket joints, being formed by the adaptation
of the head of the femur to the acetabulum of
the os innominatum. These bones are con-
nected by a very powerful capsular ligament,
which again is completely covered by strong
and thick muscles, under the influence of which
the various motions of the joint are performed.
We propose to examine seriatim the several
textures entering into the formation of this
joint, and lastly to consider the motions of
which it is susceptible.

The bones. — Of the two bones which in the
adult enter into the formation of this joint, the
os innominatum contributes by the acetabulum,
and the femur by its head.

The acetabulum (cotyloid cavity : Germ, die
Pfanne) is the cup or socket which receives the
head of the femur, and is admitted to be the
deepest articular cavity in the body. Prior to
the adult period of life this cavity serves as
the centre of union for the three bones of
which the os innominatum is formed, viz., the
ilium, ischium, and pubis. These, however,
do not enter equally into the acetabulum, inas-
much as the ischium contributes in the pro-
portion of rather more than two-fifths, the ilium
of about two-fifths, whilst the pubis yields ra-
ther less than one-fifth.

Although the acetabulum is situated nearly
in the centre of the separated os innominatum,
it has a different position in relation to the
entire pelvis. The union of the ossa innomi-
nata at the symphysis pubis, and the comple-
tion of the pelvis by the addition of the sacrum
posteriorly, place the acetabular cavities on
either side upon the antero-external aspect of
the pelvis, so that a line drawn horizontally
from the one to the other would pass through
the union of the anterior with the two posterior
thirds of the antero-posterior diameter of the
pelvis. The aspect of each acetabulum is out-
wards and very slightly forwards as well as
downwards.

Kach cavity is surrounded for about four-
fifths of its circumference by a sharp but strong
lip or margin (supercilium acetabuli), leaving
opposite the obturator foramen a notch of
considerable extent (incisura acetabuli) di-
rected from without downwards, forwards, and
inwards, the deepest part of which is smooth
and gives passage to nerves and vessels. This
notch corresponds to the junction of the pubis
and ischium ; and we may here observe that
the margin of the acetabulum exhibits a slight

NORMAL ANATOMY OF THE HIP-JOINT.

777

concavity superiorly, corresponding to the
junction of the pubis and ilium, and a similar
one inferiorly and externally, corresponding to
the junction of the ilium and ischium. These
concavities are separated by intervening con-
vexities, and hence the margin of the acetabu-
lum has the appearance of a waving line.
Immediately within the margin of the acetabu-
lum we perceive a broad band of smooth
bone (fades lunata) covered in the recent
state by articular cartilage, about seven-eighths
of an inch wide at its lower portion, or oppo-
site the ischium, an inch and a quarter to an
inch and a half superiorly and externally,
where it corresponds to the ilium, and from a
quarter to half an inch internally and superiorly
at the pubis. This band terminates at each
extremity of the notch already described in a
process (cornu), the superior of which looks
downwards, outwards, and backwards, whilst
the inferior, more prominent than the superior,
projects towards the notch, forming a kind of
gutter between its superior margin, and the
deepest part of the notch. Internal to this
band, there is a depression, as it were a cavity
within the acetabulum, rough and uneven,
uninvested by cartilage in the recent state,
being continuous with the notch leading
towards the obturator foramen. This is the
Jbvea or sinus, and lodges a quantity of fatty
cellular tissue formerly termed glands of Havers,
from their having been first described by that
anatomist. On the upper and lower portions
of this inner cavity, various inequalities and
foramina are seen, the latter being for the pas-
sage of the nutritious vessels of the bone,
which is very thin at this point, so much so in-
deed, that if held up to the light, it will be
found transparent. The depth of the acetabu-
lum is not uniform in its different regions.
This variety corresponds in a great measure to
the breadth of the smooth band of bone
(fades lunata) already described. Where
this is broadest, the cavity possesses the great-
est depth, and where it is entirely absent, the
cavity is very superficial, as opposite the notch.

The non-articular circumference of the lip
of the acetabulum is rough and marked by
foramina for the passage of nutritious vessels,
and also for the attachment of the capsular
ligament.

The head of the femur, representing about
three-fourths of a sphere, is supported and con-
nected to the shaft of that bone at an angle
varying with age, by a constricted and flattened
process termed the neck. A waving prominent
line surrounds the head at its junction with the
neck, and may be regarded as the boundary
line between these two parts, leaving on its
inner side the articular surface of the head of
the femur, which is smooth, having in the
adult its greater convexity directed upwards
and inwards. At one point, however, the ar-
ticular character of this surface is interrupted
by a depression, which is not covered with carti-
lage in the recent state. This depression, situ-
ated immediately behind and below the point
through which the axis of the head of the bone

would pass, gives insertion to the ligamentum
teres.

2. The cartilage. — That portion of the sur-
face of the acetabulum which corresponds
to the facies lunata is alone invested by articu-
lar cartilage. This cartilaginous layer is thick-
est at its external circumference, becoming
gradually thinner as it proceeds internally.
The head of the femur, on the other hand, is
nearly entirely incrusted with cartilage, which,
as is usual on convex surfaces, is thickest
towards its centre, where it is interrupted by the
depression for the ligamentum teres, and be-
comes progressively thinner towards the circum-
ference.

3. Fibro-cartilage. — Immediately surround-
ing the margin of the acetabulum is a fibro-
cartilaginous ring about three lines broad, tri-
angular in shape, having its base attached to
the brim of the cavity, whilst its apex is free.
This is the so-called cotyloid ligament (ligamen-
tum cotyloideum, fibro-cartilagineum, labium
cartilagineum acetabuli.) It clearly belongs to
the fibre-cartilages of circumference, and is
the counterpart of the glenoid ligament in the
shoulder-joint (see FIBRO-CARTILAGE), and as
it completely removes the irregular character
of the margin of the acetabulum, it will be
found to be deepest where it corresponds to the
concavities of the acetabular border. Its free
border is sharp, and directed inwards, i. e.,
towards the centre of the joint, narrowing the
orifice of the acetabulum, at the same time that
it increases the depth of that cavity. Its fixed
margin constitutes its base, and is connected to
the brim of the acetabulum ; its external sur-
face covered by synovial membrane corres-
ponds to the capsular ligament, whilst its inter-
nal, also covered by synovial membrane, em-
braces the head of the femur. Having arrived
at the notch, it is continued over each cornu of
the facies lunata, retaining somewhat of its
form, but much diminished in dimensions, and
having assumed much more the appearance of
pure cartilage than of fibro-cartilage. It ceases
at the point at which the concave margin of the
facies lunata becomes blended with the con-
vexity of each cornu. It is not stretched
across the notch as some anatomists erroneously
describe it. The whole extent of this fibro-
cartilage, then, corresponds exactly to the con-
vex margin of the facies lunata.

4. Ligaments. — The notch of the acetabu-
lum is converted into a foramen, strengthened
and in a great degree closed by ligamentous
fibres arranged in two layers, and extended
from the superior to the inferior cornu. The
whole forms the ligamentum transversale aceta-
buli of Winslow. Of these the external and
deepest arises from the superior, and is inserted
into the inferior cornu of the acetabulum. The
external surface of this layer, directed obliquely
backwards towards the cavity of the acetabulum,
corresponds and gives attachment to the liga-
mentum teres. Its internal surface is applied
to the external layer ; its external margin is
attached to the capsular ligament, and its inter-
nal superiorly to the pubis, but inferiorly it is

778

NORMAL ANATOMY OF THE HIP-JOINT.

free, and bounds a foramen for the passage of
vessels. The internal layer of the transverse
ligament is attached below to the inferior cornu,
and above to the superior, where it appears to
blend with the cotyloid ligament. By its exter-
nal surface it is in apposition with the external
layer of the transverse ligament, and its inter-
nal surface is directed towards the obturator
ligament and external obturator muscle. Some
fibres pass from its upper margin to the obtu-
rator ligament ; but in greatest part this mar-
gin contributes to form the foramen already
described for the passage of vessels. Its infe-
rior margin affords attachment to the capsular
ligament.

Round ligament. (Ligamentum teres capitis
femoris sen ligamentum inter-articulare.) —
This ligament, which was first described by
Vesalius, has very improperly received the
epithet round, inasmuch as in point of fact it is a
triangular fasciculus, about an inch and a half in
length, having its base attached to the aceta-
bulum and its apex to the depression on the
head of the femur. It is most advantageously
placed for escaping injury in the various
motions of the joint, as, independently of its
corresponding to the soft cushion contained in
the excavation of the acetabulum, its direction
and attachments completely remove it from all
danger on this score. It is attached by the
superior portion of its base to the upper cornu
of the notch, and to the external layer of the
tranverse ligament; and by the inferior and
larger portion of its base to the lower cornu, as
well as to the external layer of the tranverse
ligament; from these points of attachment its
direction in the quiescent state of the limb,
i. e. the femur being placed vertically under
the pelvis, is upwards, outwards, and back-
wards, to its insertion into the head of the
femur.*

When the joint is cut into in the recent state,
there are processes seen extending from this
ligament towards the circumference of the exca-
vation ; these should not be mistaken for por-
tions or attachments of the ligamentum teres ;
they are folds of the synovia! membrane pro-
ceeding from that ligament over the surface of
the acetabulum. Situated in the rough exca-
vation of the acetabulum, and forming a cushion
for the ligamentum teres in the several motions
and positions of the head of the femur, is the
soft pulpy mass of fatty cellular tissue, covered
by synovial membrane, already alluded to as the
glands of Havers, first described and figured by
that anatomist in his Osteologia Nova.

Capsular ligament. — The hip-joint is com-
pleted by a strong fibrous investment, termed
capsular ligament (capsula fibrosa ossis fe-
moris). This is by far the strongest and
largest capsular ligament in the body. How-
ever it is by no means uniform in its strength
and thickness, these being greatly increased by

* [Weber states that, in the erect posture, the
direction of the ligamentum teres is vertical. See
Mechanik der Menschlichen Gehwerkzeuzc, p. 143.
and pi. ii. fig. l.—ED.J

super-imposed fibres in those situations upon
which a considerable force is exercised in
certain motions of the joint. It not only em-
braces the articulation, but also includes the
neck of the femur, to the base of which it
extends from the os innominatum. Its fibres
are variously directed from the os innomi-
natum, to which they are firmly attached
from the margin of the acetabulum to a
considerable distance on the dorsum of that
bone. Superiorly and externally they may be
traced as far as the inferior anterior spinous
process of the ilium in front, whilst posteriorly
the great sciatic notch marks their boundary,
and an arched line drawn from the inferior
anterior spine of the ilium to the spine of the
ischium denotes with tolerable exactness their
attachment in this direction. Inferiorly and
externally they are attached to that portion of
the ischium situated between the cotyloid cavity
and the external lip of the tuber ischii, and to
this latter itself by very strong dense fibres.
Superiorly and internally they arise from that
portion of the ilium situated between its an-
terior inferior spine and the ilio-pectineal
eminence, and from the pubis as far as the
superior cornu of the acetabulum. Inferiorly
and internally the capsule is attached to the
transverse ligament of the cotyloid cavity.

By this description we perceive that the cap-
sular ligament is firmly attached to the os inno-
minatum ; that with the exception of the portion
arising from the transverse ligament its origins at
all points are from an inch to nearly two inches
in extent. Passing in various directions, ac-
cording to their several situations, the fibres
run to be inserted into the base of the neck
of the femur, anteriorly into the anterior inter-
trochanteric line, superiorly and externally into
the surface of the bone close to the digital
fossa at the root of the great trochanter, inferi-
orly and internally to the line leading from the
lesser trochanter to the anterior inter-trochan-
teric line, and posteriorly it is partly reflected
upwards, so as to become continuous with the
periosteum of the posterior part of the neck of
the bone ; this reflection taking place along the
posterior inter-trochanteric lime, and partly in-
serted into that line, especially at its internal and
external extremities. The reflected portion is
derived from the deep fibres of the capsule,
which in passing upwards to be inserted into
the bone at the circumference of the head, con-
tribute to form those bands of fibrous mem-
brane, which are manifest on the posterior aspect
of the neck of the femur on opening the cap-
sule, being covered only by synovial membrane.
These bands are sometimes of considerable
strength, and they are well described and
figured by Weitbrecht,* by whom they were
designated retinacula.

We have already observed that the capsular
ligament is not uniform in thickness at all
points. At the outer part of its anterior sur-
face its thickness is very considerable, being
strengthened and increased by a band of fibres

* Syndesmologia, Petrop. 1742. 1

NORMAL ANATOMY OF THE HIP-JOINT.

779

of some magnitude (accessory ligament), arising
from the inferior anterior spine of the ilium
and the space beneath, from which they descend,
diverging to be inserted into the anterior inter-
trochanteric line ; these fibres are so much de-
veloped in some instances as almost to re-
semble a distinct ligament. At this point the
capsule is nearly half an inch thick. Externally
its thickness is considerable, though somewhat
less than at the point last described. From
the pubis a smaller and thinner band of acces-
sory fibres may be traced towards the lesser
trochanter, strengthening the capsule in this
situation ; between the two accessory bands in
the centre of the anterior surface, the capsule is
extremely thin, and sometimes wholly destitute
of fibrous tissue, being altogether composed of
synovial membrane, and a little cellular tissue,
by which it is separated from the bursa that
lies under the tendon of the psoas muscle :
this bursa, moreover, sometimes communicates
with the cavity of the joint through an opening
in this situation.

The internal surface of the capsule invested
by its synovial membrane corresponds to the
cotyloid ligament, to the neck and a portion of
the head of the femur. The external is covered
anteriorly by the rectus femoris, psoas, and
iliacus muscles, internally by the obturator
externus and pectineus ; posteriorly it lies upon
the quadratus femoris, gemelli, pyriformis,
and obturator internus, and superiorly the
glutaeus minimus adheres very closely to it.

The capsule of the hip-joint, although
stronger, is not so long or so loose as that of
the scapulo-humeral articulation, neither is it
pierced by any tendon.

Synovial membrane. — To facilitate descrip-
tion, let us commence at the greatest circum-
ference of the head of the femur. From this
point the synovial membrane passes outwards
over the neck of the bone as far as the attach-
ment of the capsular ligament ; from the bone
it is reflected on to the deep surface of this
ligament, along which it passes to the line of
its attachment to the os innominatum and
transverse ligament: along that line it is re-
flected again on to the margin of the acetabu-
lum over the cotyloid ligament into the cavity,
which it completely lines, and from which it is
carried by the round ligament, which it invests,
to the head of the femur.

Arteries. — The hip-joint is supplied with
blood by branches from the obturator artery,
derived from the internal iliac or from the in-
ternal circumflex branch of the femoral. These
are distributed, some in the fat and cellular
tissue, filling the excavation at the bottom of
the acetabulum, whilst others ramify on the
ligamentum teres, and are conducted by it to
the head of the femur. It not unfrequently
occurs that the joint receives blood from both
these sources.

Nerves. — These are derived from the obtu-
rator, which uniting with the deep division of
the anterior crural cause the pain to be referred
to the knee in some diseases of the hip-joint.

Motions. — The motions of this joint are
mostly performed by the femur upon the os

innominatum, and consist of flexion, exten-
sion, abduction, adduction, circumduction, and
rotation.

In slight flexion the head of the femur
revolves upon its axis in the cotyloid cavity ;
the anterior portion of the capsular liga-
ment being relaxed, whilst the posterior is
rendered proportionally tense. If this motion
be augmented to any considerable extent, the
capsular ligament is relaxed to a greater degree
anteriorly, whilst posteriorly, in consequence of
the distance between its two points of attach-
ment being increased, it is very tense, and ren-
dered convex by being stretched over the head
of the femur, which is now very prominent in
this situation, resulting from the altered re-
lations between it and the acetabulum. The
anterior part of the head of the femur is placed
against the deepest portion of the acetabulum,
whilst its broad articulating surface situate
above the depression for the round ligament is
directed backwards, where the acetabulum is
too shallow to receive it completely ; it there-
fore forms a projection in this situation, a pro-
jection which, in my opinion, ought rather to
be attributed in this instance to the natural
formation of the parts than to any displacement
of the head of the bone.

When excessive flexion is combined with
adduction, the head of the femur glides from
before backwards, and from within outwards in
the acetabulum ; its anterior portion is con-
cealed in this cavity, whilst its posterior
emerging lies against the capsular ligament,
considerably increasing its tension. To pro-
duce these motions muscles of great power are
employed ; in some these agents are not con-
fined merely to one joint, but have two oppo-
site functions to perform, being flexors of one
joint at the same time that they extend another.

In abduction, when the lower extremity of
the femur is separated from the median line,
its head is naturally directed downwards,
its inferior portion being forced against the
capsular ligament ; therefore when the motion
is carried to any great extent the ligament is
liable to rupture, and allow the head of the
femur to escape over the internal lip of the
acetabulum into the obturator foramen.

In adduction the same occurs as in abduc-
tion, but in an inverse direction, with this ex-
ception, that as the motion cannot be carried
so far, and as in this case the head of the
femur is opposed to the deepest portion of
the acetabulum, dislocation cannot occur.
Simple adduction, unaccompanied by any
flexion of the joint, is very limited. Let
any one, while standing in the erect pos-
ture, approximate his knees, it will be found
that the utmost he can do is to bring them very
near to each other, but that he cannot press
them against each other; if, however, the hip-
joints have been previously very slightly flexed,
then the knees may be easily pressed against
each other, and the adduction may be carried to
a much greater extent, so as to cross the legs.
It is limited by the ligamentum teres and the
external and anterior part of the capsular liga-
ment.

780

ABNORMAL CONDITIONS OF THE HIP-JOINT.

Circu induction combining the four preceding
is a compound movement, in which the inferior
extremity describes a cone, the apex of which
is at the joint ; the head of the femur in the
course of this motion successively assumes the
several situations already described.

In rotation outwards the head of the femur
is directed forwards and inwards, the anterior
surface of the neck looks outwards, the pos-
terior inwards resting on the brim of the ace-
tabulum; the capsular ligament is put upon
the stretch on its inner side. Any sudden jerk
or violence when in this position is liable to
produce dislocation upwards upon the pubis.

In rotation inwards the bone assumes the
contrary direction, and the capsular ligament
and ligamentum teres are equally put upon the
stretch. In this case dislocation may occur
either upon the dorsum of the ilium or into the
sciatic notch. For this motion we have but few
muscles, this position being produced merely
by the tensor vaginae femoris and anterior fibres
of the gluteus medius muscles. The disparity
between the number of muscles influencing the
motions of rotation outwards and inwards is
very striking, but this may be attributed to the
direction of the acetabulum from within out-
wards and forwards naturally tending to pro-
duce rotation inwards. Consequently before
the opposite motion can be effected there is
this inequality to be overcome, and hence the
disparity between the muscles.

(H. Hancock.}

HIP -JOINT, ABNORMAL CONDI-
TIONS OF THE— In this article we shall
adopt an arrangement similar to that which we
have followed in our former observations on the
abnormal conditions of particular joints, and
consider these states under the heads of, 1.
congenital malformations; 2. the effects of
disease, arid, 3. the results of accident.

SECTION I. Congenital malformation of the
hip-joint. — The peculiar affection termed by the
continental surgeons congenital or "original lux-
ation " of the hip-joint, has not in our islands at-
tracted the notice that it seems to us to merit.
When we reflect upon the very valuable addi-
tions which have been made to our knowledge of
the pathology of the articulations by British
writers, and observe their silence upon this ab-
normal state of the hip-joint, we might be led
to infer that this malformation had no existence
in these islands; this, however, unfortunately is
not true.

In the very valuable museums in London we
can easily recognise many unquestionable spe-
cimens of this congenital malformation of the
bones of the hip-joint. In Dublin we know
some living examples of it, and our museums
contain preparations shewing some of its va-
rieties and most of its usual anatomical charac-
ters.

At the meeting of the British Association in
Dublin in the year 1835, Dr. Hutton made
some interesting observations on this affection
to the section of medical science, and gave an
account of a well-marked example of it affect-
ing one hip-joint. On that occasion Dr.

Handy side observed that he had met with a
case of congenital luxation of both hip-joints,
in a subject which had been brought into his
anatomical rooms at Edinburgh ; and he added
that the appearances of the joints corresponded
very closely with those noticed by Dr. Hutton.
The Professor of Anatomy and Surgery to the
University of Dublin, Dr. Harrison, laid before
the Surgical Society last winter the results of
two accurate post-mortem examinations which
he had made of this malformation of the hip-
joint. The history of these cases, as far as Dr.
Harrison could make it out, shewed that the
subjects of them had during life presented the
ordinary signs of the infirmity in question.
In one of them, one hip-joint only was af-
fected ; in the second, not only was the arrest
of development such as to leave the acetabu-
lum a plane surface by depriving it of border
of any kind, but the ligamentum teres, the
head and greater part of the cervix femoris
were also deficient on both sides, so that the
femora at their upper extremity presented a
rude resemblance to the ossa humeri. In this
case (fig. 307) the capsular ligament was of an
extraordinary length, and permitted the rudi-
ment of a head and neck, with the trochanter
major, to ascend and descend on each side on
the dorsum ilii, and to pass backwards on the
ischium to the very edge of the ischiatic notch,
in the different movements of the patient.

The case of congenital malformation of the
hip-joint has not escaped the notice of conti-
nental surgeons,* although perhaps the nature of
the affection had not fully attracted the attention
of the profession until Dupuytrenf gave the
results of his observations of twenty-six cases of .
this malformation which were presented to him
in the course of his public and private practice.
He seems to have met with the affection more
frequently in the female than in the male, in
the vast proportion of twenty-two females to
four males, and from his description it would
appear that he has usually found, in the same
individual, both hip-joints affected. In the
cases we have witnessed, we have not observed
this very great preponderance of female over
male cases ; and although we have noticed the
defect to be double in the same individual, we
have more frequently observed but one joint
engaged. This is of importance to be recol-
lected, as mistakes in our diagnosis are more
likely to occur when only one joint is affected,
than in those cases in which the defect is
double in the same individual.

The characters, says Dupuytren, of this
" original luxation" are nearly similar to all
those we notice belonging to the ordinary luxa-
tion upwards and backwards on the dorsum
of the ilium : the limbs are shortened and inver-
ted ; the superior extremities of the femora are
carried upwards, backwards, and outwards, into
the external iliac fossa, where a considerable
prominence can be seen, caused by the unusual
elevation of the great trochanter; the thighs,
unusually slender, are obliquely directed down-

* Pallctta, Lafond, Callard, Bellomeir.
t Repertoire d'Anatomic, Lemons Orales.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

781

wards, forwards, and inwards, and this obliquity
is greater in proportion as the pelvis is broader;
hence the deformity in the female increases
about the age of puberty : there is, in conse-
quence of this breadth of the pelvis, a tendency
of the limbs to cross each other inferiorly, and
the movements they are found to enjoy are
very limited, particularly those of abduction
and rotation ; hence the individual finds great
difficulty in performing the different functions
belonging naturally to the inferior limbs.
When we examine a person with this double
defect standing, we are struck at once with the
apparent want of proportion between the superior
and inferior parts of the body, with the imper-
fection of the lower limbs, and with the peculiar
attitude of the patient. The trunk is fully deve-
loped, says Dupuytreu, whilst the inferior limbs,
short and slender, seem as if they were suited
only to an individual of smaller stature, When
we view the patient laterally, we observe that the
chest and superior part of the body are carried
very much backwards, while the anterior part
of the abdomen is thrown very prominently
forwards, and at the same time we notice there
is a corresponding hollowing posteriorly in the
region of the loins, and that the nates jut out
backwards most conspicuously. A very cha-
racteristic circumstance relative to the standing
position of these malformed individuals is, that
they rest on the ground only by the anterior
part of their feet; most of the peculiar cir-
cumstances relating to the attitude of these
persons follow as the necessary consequence of
their hip-joints (or in other words the centre
of motion of the lower extremities) being placed
behind their ordinary situation with respect to
the pelvis.

If a patient so unhappily constituted wish to
walk, we see him incline the superior part of
his body towards the limb which is now in-
tended to support the weight of the body ; he
as it were balances himself on the anterior part
of the foot of this side ; he next raises from the
ground the opposite foot, and transfers labori-
ously his weight from one side to the other —
indeed each time this motion takes place, the
head of the femur which receives the weight of
the body, ascends upon the external iliac fossa,
and is sustained by its ligaments and muscles ;
the pelvis is at the same time depressed, and
all the signs of displacement become more ob-
vious on this side, while they diminish sensibly
on the other ; in a word, progression thus be-
comes an awkward and waddling movement.

It may appear singular that running and
leaping should be executed by these patients
with more facility than walking, yet such is
the fact; for in those exertions the energy of
muscular contraction, and the rapidity with
which the weight of the body is transferred from
one limb to the other, are such, that the want
of a true acetabulum is not so much felt
as in walking. Any of these exercises, how-
ever, very soon induce fatigue, which we can
readily account for when we recollect the
friction which the head of the femur must un-
dergo against the side of the pelvis, and the
great efforts which the muscles have to sustain

in supporting the weight of the body, during the
balancing or waddling motion described. When
persons afflicted with this malformation lie
down horizontally on their back, the signs of
their infirmity become so slight as to be
scarcely perceptible, because in this situation
of complete repose the muscles do not draw
upwards the lower limbs, nor does the weight
of the body depress the pelvis. Dupuytren
found that in this situation of the body he
could elongate or shorten the affected limbs
of the patient; to elongate them, he says, it
was merely necessary to pull slightly down-
wards at the knee or ankle, and to shorten
them, to push them upwards; the head of the
femur will undergo in such experiments a dis-
placement of one, two, or even three inches
(Dupuytren), and all these displacements will
be affected without causing any pain and with
the greatest ease, convincing us that no proper
cavity exists fit to receive and retain the head
of the femur.

It is of importance that this congenital mal-
formation of the hip-joint should be well under-
stood, not only that dangerous errors in diagnosis
may be avoided, but that this defect, when it
really exists, may be recognized early, so that
timely and proper treatment may be resorted to.
It presents to the superficial observer many of
the signs which belong to a disease of the hip-
joint ; and of the cases seen by Dupuytren, few,
he says, had been recognized by the surgeons
previously consulted : almost all these unfor-
tunate patients had been subjected to painful and
worse than useless treatment. Many individuals
afflicted with original luxation of the hip-joint
have been, in consequence of the errors or igno-
rance of their medical attendants, condemned
to keep their beds during many years. " I have
seen others," says he, " whom they had forced to
submit to numberless applications of leeches,
blisters, issues, and moxas; among others I
remember the case of a young girl, who suffered
the application of twenty-one moxas around the
hip, without this barbarous treatment having
effected any favourable change in the situation
of this unfortunate patient."

We can easily distinguish this original
luxation from disease of the hip-joint, as there
is no pain felt by the patient either in the hip
or knee ; there is neither heat, swelling, nor
abscess, no evidence of inflammation chronic or
acute, nor is there any cicatrix ; consequently
nothing exists which can induce us to believe
that heretofore there ever existed any abscess or
fistula, consequences so very usual in cases of
disease of the hip-joint, when this disease has
arrived at the stage of luxation.

Dupuytren's description of this condition of
the hip-joint seems to apply altogether to the
case in which both joints are engaged ; when
one articulation only is affected, so far as
it is concerned, the features of the congenital
defect are just as well marked as those above
alluded to. The usual signs of the dislocation
upwards and backwards on the dorsum ilii, and
the same range of ascent and descent of the head
of the femur on the ilium and towards the ischi-
atic notch, is noticed as in the former case ; as,

782

ABNORMAL CONDITIONS OF THE HIP-JOINT.

however, the weight of the body is almost
entirely thrown on the unaffected limb, the
latter becomes much larger and stronger than
usual, while the malformed limb falls into a
state of more or less of atrophy from want of
use; its circulation in general seems more
languid, and its nervous energies and tempera-
ture are less than those of the well-formed ex-
tremity ; add to this, as we have already noticed
(what might be expected,) that in consequence
of the centre of gravity being so uniformly
thrown on the sound limb, a lateral curvature
of the spine takes place, and a great mobility
of the sacro-lumbar articulation exists.

Anatomical characters of this affection. —
Opportunities for ascertaining the anatomy of
this congenital defect, whether both hip-joints
be implicated or one only affected, are very
rare. Although Dupuytren has seen so many
patients afflicted with this malformation, he has
had very few opportunities, he says, of study-
ing its anatomy, because the affection is not a
disease, but an infirmity which has no tendency
to shorten life. With respect to the muscles he
has remarked, that some of them around the
joint are found to be well developed, while
others are in a state of atrophy : the first are
those which have still preserved their functions,
the second are those whose action has been
restrained by changes induced in the position
and form of 'the parts : some of these latter, he
says, are reduced to a sort of yellow fibrous
tissue, in which we can scarcely discover mus-
cular fibre.

The cotyloid cavity of the os ilii in some
cases scarcely can be said to exist, so irregular
are the traces of it; sometimes an irregular
bony eminence occupies its place, having no
cartilaginous covering, no rudiment of cotyloid
ligament ; it is merely surrounded by resistant
cellular tissue, and covered by muscles which
pass by it to be inserted into the little tro-
chanter. Sometimes, says Dupuytren, I have
found the ligamentum teres of the articulation
much elongated, flattened superiorly, and worn
as it were in certain points by the pressure and
friction of the head of the femur ; the latter is
lodged in a cavity analogous enough to that
which we find formed in cases of luxation up-
wards and outwards, which have been left for a
long time unreduced. This cavity (if such it
can be called) is situated in the external iliac
fossa, above and behind the usual situation of
the cotyloid cavity, at a height proportioned
to the shortening of the limb, or degree of ascent
of the head of the femur. The superior portion
of the femur preserves in all its parts, its form,
its dimensions, and its natural relations, only
the internal side, and the anterior part of the
head of this bone has sometimes lost its
rounded form, a circumstance which would ap-
pear to result from the friction which it has been
subjected to by its frequent contact with parts
which have not been organized to receive it.

The writer's observation does not entirely
correspond with this account of the superior
portion of the femur preserving its form and
natural relations with the rest of the bone. He
has usually noticed that the head of the femur

has lost its spheroidal shape, and presents
somewhat of a conical appearance, as Dupuy-
tren well describes ; but two other circumstances
he has observed in almost all the cases he has
examined, whether in the recent dissections he
has himself witnessed, or in the macerated
bones he has seen in Dublin or elsewhere : —
1st, that the neck of the femur, instead of
having its axis directed, as it naturally is, from
behind forwards, upwards, and inwards, lias in
this malformation lost its usual relation with
the shaft of the thigh-bone, and the axis is
directed upwards, and almost directly forwards.
This alteration in the direction of the axis of
the neck of the thigh-bone did not escape the
observation of Dr. Hutton, in his remarks on
his case already alluded to ; he expressed his
idea of the altered direction of the axis by say-
ing that the axis of the neck in this case fell
directly on the anterior part of the upper ex-
tremity of the shaft : " the relative position of the
neck and shaft appeared as it might be supposed
to do if, the lower portion of the femur being
fixed, the upper portion were twisted forwards,
the head moving through one fourth of a circle."
2dly. The other circumstance which the writer
has noticed must be viewed in connec-
tion with this altered direction of the usual
axis of the neck of the femur just alluded to ;
it is that in all the cases he has as yet seen of
this original luxation of the femur, the head of
the thigh-bone, instead of being directed back-
wards, as it is in the ordinary luxation on the
dorsum ilii, on the contrary has been directed
forwards, and has been placed beside the
anterior inferior spinous process of the ilium,
while the trochanter major has been directed
backwards on the dorsum ilii.

It is rather strange that a relative position of
the bones of the hip-joint, so different from
what has been observed in the ordinary dis-
location upwards on the dorsum ilii, and one
so usually met with in the case of original lux-
ation of the hip-joint, should have heretofore
escaped observation.

In one of the specimens of malformation of
the hip-joint preserved by Mr. Harrison in the
Museum of the University of Dublin, this
relative position of the femur and the anterior
inferior spine of the ilium can be noticed,
while the trochanter major is placed posterior
to both. And in two preparations preserved
in the Richmond Hospital Museum, the same
observation can be made, — the atrophied heads
of the thigh-bones are directed forwards ; the
great trochanters lie behind these heads on the
sides of the pelvis.

These are circumstances important for us to
keep in mind, when we are considering the
diagnosis of the various affections of the hip-
joint.

We say that such a remarkable circumstance
demands notice from us, because in the cases of
this affection we have as yet observed in the living
subject, the thigh, leg, and foot of the malformed
limb has not been so much inverted as it
always is in the ordinary luxation upwards and
backwards on the dorsum ilii; indeed in the
case of a lad, named Hannon, whom the writer

ABNORMAL CONDITIONS OF THE HIP-JOINT.

783

has frequently examined, (jig. 308,) the thigh,
leg, and foot were by no means inverted, the
ordinary aspect of the front of the femur, patella,
&c. was directed as much forwards as it
naturally is ; the shortening and other signs of
luxation upwards on the dorsum ilii existed,
and, in consequence of the emaciated state of
the limb, the relative position of the head and
neck of the femur, above adverted to, was easily
recognized, when the hand was laid upon the
head of the bone, and a strong movement of
rotation outward was communicated to the mal-
formed extremity.

We do not mean to assert that in all cases
this relative position of the head and neck of
the femur will be found to exist; in this, as in
other congenital defects, much variety may be
expected to be found. When in these cases
the soft parts are removed, the bones of the
pelvis present appearances which are remark-
able enough, although we believe that these
appearances have heretofore escaped the obser-
vation of anatomists, who seem to have confined
their attention to the abnormal condition of the
head of the os femoris and the acetabulum.

The anterior spines of the ilium, particularly
the inferior, we have usually found to be directed
very much inwards, towards each other (Jig.
307); the external iliac fossa to be more convex,
and the internal iliac fossa more concave than
usual : beneath the anterior inferior spine we no-
tice a deep groove directed outwards, through
which the united tendon and fibres of the psoas
and iliacus pass to the lesser trochanter of the
femur, which process is always in these cases
placed so much behind as well as above its nor-
mal situation. The sub-pubic angle is remark-
ably obtuse, the rami of the pubes and ischia
are very oblique, and the tuberosities of the
ischia greatly everted.

Fig. 307.

Many of these which we would call charac-
teristic features of the double congenital defect
now under consideration have heretofore escaped

the notice of all those who have written on
" the original luxation" of the hip-joint. San-
difort in his Museum Anatomicum has, how-
ever, given a delineation of a pelvis belonging
to a subject in which he says both hip-joints
were found dislocated: what this author has
there drawn was probably not understood in
his day, but any one who has seen many spe-
cimens of the deformity we are now endea-
vouring to describe, will agree with us, we are
sure, in considering Plate LXIV a true repre-
sentation of congenital luxation in both hip-
joints.

When only one of the hip-joints is affected
we find a lateral curvature of the spine to exist,
and the bones of the pelvis to be in a state of
atrophy on the malformed side. The portions
of the os pubis and ischium which circum-
scribe the thyroid foramen are generally long
and slender, and the tuberosity of the is-
chium is at a greater distance from the sym-
physis of the pubis on the malformed than on
the opposite side.

Many of the anatomical characters we have
here stated may be supposed to be the gradual
result of causes acting from early infancy on
bones as yet soft and cartilaginous. The weight
of the body so constantly acting unfavourably
on badly-formed bones and over-distended liga-
ments, the efforts of muscles by their repeated
exertions endeavouring to supply the defici-
encies in the ligaments and in the articular sur-
faces of the bones, are so many causes which
must act on and alter the direction of the head
and neck of the femur, distort the tuberosities
of the ischia, and draw towards the middle
line the spines of the ilium; but we may inquire
does the first fault in these cases consist in the
arrest of development in the bones? in the
muscles? or should we look to the nervous
system for the primitive source of these intra-
uterine defects ? These are inquiries which can-
not, we believe, in the present state of our know-
ledge, be satisfactorily replied to. Andral re-
marks that in almost all cases in which one of
the cerebral hemispheres is atrophied we find
the limbs of the opposite side less developed
than natural ; but he does not venture to ex-
press an opinion as to whether the imperfect
de/elopment of the brain is the cause of the
malformed extremity, or the repose and want
of use of the latter the reflected cause of the
atrophy of the brain. No doubt we have, in
one solitary instance already quoted,* shewn
that a congenital malformation of the left hip-
joint coincided with a deficiency of the cerebral
convolutions of the right hemisphere of the
brain, but this coincidence we have reason to
believe must be exceedingly rare.

Some surgeons of eminence, whose opinions
must have considerable weight with the pro-
fession, have stated it to be their belieff that
" a simple paralytic condition of the muscles of
the lower extremity, as a consequence of the
irritation from teething arising during infancy,"
is the starting point of disease in these cases,

* Dr. Hutton's case, Dublin Journal, volume viii
t See Lancet for 1825-6.

784

ABNORMAL CONDITIONS OF THE HIP-JOINT.

and would of course consider all the pheno-
mena of the malformation we have dwelt on,
as the mere consequences of the paralytic con-
dition of the muscles. With such a doctrine
we are not at all disposed to agree; in no other
instances do we find paralysis produce similar
results; besides, the muscles of the hip-joints
in many of these cases seem in the exercise of
running and leaping endowed with very ener-
getic powers of action. It is perfectly clear
that to refer all in these cases to a paralysis of
the muscles is quite unsatisfactory, because the
abnormal conditions of the several structures
around the affected joints are in these cases so
varied and numerous that we feel that they
never can be rationally referred to this single
source. In some instances we find a very well
marked oval eminence on the side of the pelvis
for articulation with the malformed head of the
femur, while no trace of cotyloid cavity exists;
in some the defect is slight, in others the de-
formity is great; thus the ligamentum teres
may be a long and slender thread without vas-
cularity or strength in some cases, in others we
have seen it four inches long, and at the same
time of considerable breadth; while in others
again no trace of ligamentum teres or head of
the femur existed, the imperfect representation
of a head being retained by a lengthened cap-
sular ligament, supported by the smaller mus-
cles around the malformed articulation.

These observations satisfy us that we cannot
refer to " paralysis of the muscles of the lower
extremity as a consequence of irritation from
teething arising during infancy," the pheno-
mena that this affection termed congenital mal-
formation of the hip-joint presents.

We have no doubt seen some instances in
which a certain paralytic tendency and other
congenital defects seemed combined with the
malformation of the hip-joint ; but again we
have seen many others in which there was no
paralytic tendency, and in which no other de-
fect than a double congenital luxation of the
hip-joint existed ; and in Dupuytren's twenty-
six cases no mention is made of paralysis, nor
of atrophy of the cerebral convolutions.

We confess we are glad to feel ourselves able
successfully to oppose the hopeless idea of pa-
ralysis of the muscles being in fault, because
we have reason to believe that mechanical treat-
ment of the malformed hip-joint has succeeded,
when early applied, in lessening the infirmity.
The idea of paralysis of the muscles being the
root of the evil, precludes all hope of mecha-
nical treatment being at all serviceable to these
unfortunate individuals.

History of a case of congenital malformation
of the left hip-joint, with the anatomical exa-
mination of the articulation. — A man named
John North, set. 31, of weak intellect, was
admitted under the care of Dr. Hutton, July
1835, into the Richmond Hospital; he was
afflicted with a most severe form of inflamma-
tion of the larynx, trachea, and lungs. I was
asked to visit him, and report my opinion as to
whether the operation of tracheotomy should
be performed, or whether such a measure would
be calculated to relieve the urgent symptoms of

dyspnoea which seemed in this case to threaten
suffocation. While I was examining the pa-
tient he wished to get out of his bed, and then
I noticed that besides having an atrophied and
contracted state of the left forearm and wrist,
his left lower extremity was deformed, and
seemed much shorter than the opposite limb.
Upon even a very superficial view of this left
hip-joint and the position of the limb, all the
more obvious features of a dislocation up-
wards and backwards on the dorsum ilii, were
recognized. Upon inquiry it was ascertained,
as far as could be from such a patient and from
his ordinary attendants, that the hip-joint had
never suffered any accident, and that, although
he had issues inserted, he never had had any
acute disease or suffering in the deformed hip,
which deformity, with the contraction of the
upper extremity, was coeval with their earliest
recollections of him.

I agreed with those in consultation on the
case that the state of the lungs would speedily
bring about the death of the patient, and that
no operation, such as tracheotomy or laryngo-
tomy, should be resorted to. I also expressed
my conviction that the left hip-joint presented
a very fine illustration of the abnormal state of
this articulation, which Dupuytren and others
had described as a congenital or original luxa-
tion of the hip. The next day the patient died
of the inflammatory affection of the chest, and
a post-mortem examination was made by Dr.
Hutton, at which Mr. Smith and the writer
were present. There were observed the same
appearances of luxation on the dorsum ilii
as before noticed ; the body being held up and
maintained in the erect posture, the pelvis was
seen to be very oblique and elevated towards
the malformed side, the left lower extremity
seemed three inches shorter than the right or
perfectly formed limb, but on measurement it
was plain that the deformed limb was not
really shortened, but had merely ascended on
the dorsum ilii. The trochanter major (natu-
rally on a level with the horizontal ramus of
the pubis) was elevated two inches above this
bone. In the prominence and elevation of the
great trochanter, in the semiflexion and adduc-
tion of the limb, in the circumstance of the
motions of rotation and abduction being li-
mited,— in all these the case nearly resembled
the ordinary luxation on the dorsum ilii, whe-
ther produced by accident or the result of an
old caries; but the history of the case was op-
posed to either of these conjectures, and the
marks of issues placed there through ignorance
were not to mislead us, or induce us to alter
our opinion already expressed, as we were well
aware that in almost all the cases seen by Du-
puytren similar evidences of surgical ignorance
of the true nature of the affection had existed.
Besides the unusual prominence and elevation
of the trochanter major already mentioned, the
head of the femur could itself be plainly enough
felt, when a movement of rotation outwards was
given to the shaft of the bone; but when the
limb was forcibly elevated or extended, even
now in the dead subject, its range of move-
ment of ascent and descent was not more than

ABNORMAL CONDITIONS OF THE HIP-JOINT.

785

half an inch ; in this particular this case dif-
fered from those given by Dupuytren, because
in his cases the range of motion of ascent and
descent of the head of the femur on the os
innominatum, which could be communicated,
amounted to two inches.* The body having
been placed on its face, and the integuments
removed from the glutseus maximus, this
muscle looked somewhat paler in its colour
than natural, its lower margin (which in the
natural state has a descent of obliquity amount-
ing to three inches) was placed nearly trans-
versely. When this muscle was removed, the
trochanter major presented itself; it lay on the
dorsum of the ilium, near to the ischiatic
notch, above the pyriformis and below the
range of the glutsei (medius et minimus), which
were in a state of atrophy. The head of the
femur, smaller than usual, was in advance of
the great trochanter, and was placed immedi-
ately external to the anterior inferior spinous
process of the ilium, and was here covered
immediately by the capsular ligament and some
scattered fibres of the lesser glutaei : the tensor
vagina? femoris lay in front of the head of the
bone.

The pyriformis and quadratus were very
oblique in their course, passing upwardsand out-
wards : all the muscles in the front of the thigh,
such as the pectinalis and other adductors, passed
from the os pubis outwards with a degree of ob-
liquity three or four inches less than natural.
The psoas magnus was drawn a little outwards,
and its edges were twisted so that the internal
edge was directed backwards and its external
edge forwards. All the muscles of this ex-
tremity were smaller and less developed than
those of the other; but with the exception of
part of the obturator externus which looked
fatty, their fibres had a natural appearance.
There were no marks of previous violent injury
or chronic disease.

The capsular ligament was attached as usual
to the circumference of the acetabuluin on one
part, and to the base of the neck of the femur
on the other; it was strong and at the same
time elongated, so as to allow the head of the
femur to rest on the dorsum of the ilium, but
ligamentary bands passed from this part of the
ilium to the external surface of the capsule,
where it invested the head of the femur; these
must have served to strengthen and fix the
capsule and thus prevent any great range of
motion over the ilium. When this capsule
was cut into, the head of the femur was found
somewhat conical in its form and much smaller
than usual; the cartilaginous covering, thin and
of an azure hue, did not form a very uniform
or perfect covering for the head of the bone ;
there seemed no deficiency of synovial fluid
within the joint. The inter-articular liga-
ment or ligamentum teres, as it is called, pre-
sented a very remarkable appearance ; it was
of unusual dimensions, being more than four
inches long; of a yellowish colour like tendon,
and as thick as the tendo Achillis near the os

* See Dr. Button's account in the Dublin Jour-
nal, vol. viii.
VOL. II.

calcis ; instead of being firm, round, and thick,
it was soft and could be easily spread out to
the breadth of an inch : its fibres were con-
nected by means of a thin transparent mem-
brane like a synovial structure. This sub-
stitute for the normal ligamentum teres was
continuous with the cotyloid ligament, or arose
from that part of it which completes the notch
of the acetabulum within. From this origin or
attachment, the ligament passed, as it were,
from within outwards and upwards to be at-
tached to the head of the femur, presenting in
its course an inverted arch, the cavity up-
wards and inwards, the convexity downwards
and outwards. On its inferior surface it cor-
responded to the head of the femur, where it
was hollowed out from before backwards, so as
to accommodate itself to the head of the bone,
for which it formed a kind of cup which follow-
ed the movements of the femur, affording it
always a receptacle as the inter-articular carti-
lage does for the condyle of the lower jaw. This
broad ligament had no connexion by synovial
folds or fibrous productions with the bottom of
the acetabulum. The cotyloid ligament was
flattened out round the brim of the acetabulum,
and was otherwise imperfect: the fatty and
vascular cellular structure named Haversian
gland existed in rather large quantity.

When a comparative view of the bones of the
pelvisand lower extremity of each side was taken,
it was manifest that the left lower extremity was
in a state of atrophy, that the thigh-bone was
straight and slender, and that the atrophy ex-
tended downwards to the bones of the leg,
and included also the whole of the left os
innominatum ; the anterior spines and crest of
the ilium were inverted, the internal iliac fossa
was much deepened, and the external surface
of the ilium rendered more convex than usual.
The rami of the os pubis and ischium seemed
more attenuated and slender than those of the
opposite side, and the foramen ovale wider.
The circumference of the acetabulum of this
side included nearly as large a space as usual,
but the upper and outer portion of its brim or
its supercilium was deficient. This cavity was
shallow, its surface scabrous or uneven, and
was nowhere invested with cartilage; a flattened
surface above it marked the point of habitual
contact of the head of the femur and ilium :
the bone was not excavated in this situation to
receive the head of the femur, which was re-
tained here, as already mentioned, by liga-
mentous bands, which extended from this part
of the ilium to the external surface of the cap-
sular ligament. The femur, it has been satd,
was atrophied at this side and slender, but it
was of the same length as the opposite bone,
diminished only in the circumference of the
shaft. The axis of the head and neck was
directed from the shaft of the bone upwards
and inwards, but it was straighter, and its di-
rection was by several degrees more forward
than natural.

As we have detailed this case merely as an
illustration of the congenital malformation of
the hip, and do not wish here to enter into
minute particulars as to the morbid appear-

3r

786

ABNORMAL CONDITIONS OF THE HIP-JOINT.

ances which the post-mortem examination fur-
ther disclosed, we merely state that evidences
of diffuse inflammation of the mucous and
submucous tissues of the pharynx and larynx,
with purulent infiltration in the submucous
tissue, existed with extensive bronchitis, as
well as splenization of the lungs. It was more-
over discovered that the right hemisphere of
the brain was deficient, and that a cyst five
inches in length and between two and three in
its transverse diameter occupied the interval
(which was an inch in depth) between the sur-
face of the atrophied brain and interior of the
calvarium ; this cyst was filled with limpid
serum.

The whole of the left upper extremity was
in a state of atrophy, flexed at the elbow and
wrist-joints, and the forearm and hand were
rigidly pronated.

A case of congenital luxation of the left hip-
joint very similar to the foregoing was under the
writer's observation for some time as an out-pa-
tient of the Richmond Hospital. This lad was
on different occasions seen and prescribed for
by Dr. Hutton, who first recognized the nature
of the case, and the other surgeons of the insti-
tution. His name was Martin Hannon; he was
a labourer, aetat. 19 years. In his ordinary
attitude, standing, the spine wa? curved laterally
to the well-formed side, so that the line of gra-
vity seemed to pass to the ground through the
centre of the right or well-formed thigh and
leg : on this side the pelvis was depressed, and
on the opposite side elevated, so that the left
lower extremity appeared three inches shorter
than the right. The oblique position of the
pelvis above alluded to accounted for much of
this apparent shortening, which nevertheless,
by accurate measurement from the spine of
the ilium to the inner malleolus, was proved
to be real to a certain extent, viz. one inch and
a half. Next to the shortening of the limb,
the most remarkable circumstances which
caught our attention were the prominency and
elevation of the trochanter major, which was
found to be two inches above the horizontal

Fig. 308.

ramus of the pubis. The trochanter major was
also behind its usual situation ($g.308). The
hip-joint possessed a certain degree of the mo-
tions of flexion and abduction, and when the
patient was directed to extend the thigh back-
wards, the motion about the sacro-lumbar arti-
culations seemed preternaturally free. When
the hand was placed on the left hip-joint, the
head of the femur could be felt plainly to be
situated in a very unusual position, namely,
forwards and upwards, close to the anterior
inferior spine of the ilium, and in advance
of its neck and the great trochanter, which
lay towards the ischiatic notch : if now a
motion of rotation outwards were commu-
nicated to the femur, the trochanter major
moved backwards, while the head of the femur
rolled forwards and outwards; and so very thin
was the patient that the head of the bone could
be seen and easily felt moving in this novel
situation. The deformed thigh was at its upper
part thrown much outwards (Jig. 308), and to re-
cover, as it were, this deviation outwards above,
it passed much inwards towards its lower ex-
tremity; the thigh and leg were cold and
atrophied, and the poor lad had also that mal-
formation of the ankle called valgus.

He walked with the assistance of a stick,
and in consequence of the double defect of the
left hip-joint and ankle very imperfectly.

The sound limb, which seemed, in standing,
to bear the whole weight of the body, was
very muscular, and was larger in proportion
than to be expected, when compared with the
left or deformed leg, thigh, chest, and upper
extremities, which last presented no peculi-
arities.

Such were the notes the writer had taken of
this case in December 1837, when the lad ap-
plied to him at the hospital to be relieved of
an indolent ulcer he had on the weak limb.
In the beginning of the spring of this year
he became affected with phthisis, and died of
that disease in the Whitworth Hospital on the
12th June, 1838. Mr. Smith had a cast taken
of the lower part of the body, pelvis, and lower
extremities, which is preserved in our Museum.
The interior of the thorax presented the usual
effects of phthisis.

Left hip-joint. — The muscles around the
joint were remarkably pale and greatly attenu-
ated ; they held the same position relatively to
the head of the bone, as in the preceding case
of North, but they were more atrophied ;
in many places all appearance of muscular
fibre was lost, and its place supplied by a
yellow fatty fibrous tissue. The muscles of
the rest of the extremity, particularly the gas-
trocnemius and soloeus, were in a similar con-
dition. The sciatic nerve had not a very
healthy aspect; it was yellowish ; and its fibres,
though firm, were more loosely connected than
usual.

The capsular ligament was remarkably thick,
and was lined on its interior or synovial surface
with a very red vascular membrane, like scarlet
cloth. The internal ligament of the joint or
liqamentum teres was fully three inches long,
and much stronger than usual (fg- 309); it

ABNORMAL CONDITIONS OF THE HIP-JOINT.

787

Fig. 309.

grew to the cotyloid ligament at the notch, as
is usual, and had no other connexion with the
acetabulum, which contained no Haversian
gland, and was not lined by cartilage. The coty-
loid ligament was very flat and imperfect.

Bones. — In the general aspect of the bones
of the pelvis and of the femur, there existed a
very striking resemblance between this case
and the former detailed. The os innominatum
of the left or deformed side, together with the
femur and other bones of the left lower ex-
tremity, were much smaller than the os inno-
minatum and bones of the right lower ex-
tremity ; the former, besides being deformed,
were also in a state of atrophy in circumference
and length, while the latter were evidently larger
and better nourished than one would expect to
find them in so delicate an individual. In a
word, there was a compensatory growth of the
skeleton on the right side, as it were to make
up for the deficient growth of the left or mal-
formed side. The head of the right femur and
the corresponding acetabulum were both very
large, the right half of the pelvis too, in all its
bony prominences, was well marked, and the
anterior spines of the ilium were inverted ; the
inter- vertebral substance intervening between
the last lumbar vertebra and base of the sacrum
was much thicker than usual.

SECTION II. Disease.— The abnormal ap-
pearances we notice in the articulation of the
hip, produced by disease, are usually the result
of inflammation, which may have been either
acute or chronic ; arising either in the synovial
membrane, the cartilage, or the bone. Indeed,
in modern works on the diseases of the joints,
we have laid down for us rather positively the
symptoms and anatomical characters of syno-
vitis, chondritis, and osteitis ; but much as we
would wish to adopt an arrangement that the
pathology of Pinel and Bichat would suggest,
and which comes commended to us by the ex-
perience of Brodie, we do not think that this
arrangement can be strictly adhered to. In
acute rheumatic arthritis, we have the synovial
or fibro-synovial structures of the articulation
engaged, with little, if any, implication of the
cartilage or bone, but in any of the cases com-
monly denominated " disease of the hip," the
inflammation, as far as our experience has gone,

never long confines itself to any one structure
entering into the composition of the joint. In
a work, however, like this, the opinions of the
highest authorities on such a question must be
quoted . According to Sir Benjamin Brodie,*
synovitis coxae, or inflammation of the syno-
vial membrane of the hip-joint, may take place
in different degrees of intensity ; but for the
most part it has the form of a chronic or slow
affection, which, while it impairs, does not de-
stroy the functions of the articulation. In the
hip, less frequently than in other joints, is the
fluctuation of the effused fluid perceived, but
the existence of swelling is sufficiently evident
beneath the muscles : there is fulness of the
groin and pain, which is not " referred to the
knee, as in cases of ulceration of cartilage, but
to the upper and inner part of the thigh, im-
mediately below the origin of the adductor
lougus ; the weight can be borne on the af-
fected limb, and pressure against the heel gives
no pain ; this (the pain) is often severe, yet it
does not amount to that excruciating sensation
which exhausts the powers and spirits of the
patient, in whom the cartilages of the hip are
ulcerated."

The following case Sir B. Brodie adduces as
an example of inflammation of the synovial
membrane of the hip, terminating in disloca-
tion.

Master L.,f being at that time about eight
years of age, was attacked towards the end of
September, 1824, with what was believed
at the time to be inflammation of one of
the parotid glands, attended with a good deal
of fever ; after six or seven days, and appa-
rently in consequence of the application of
cold lotions to the cheek, the inflammation left
the parotid gland, and attacked one shoulder and
arm ; and at the end of two or three days more
it left the shoulder and attacked one of the hips.
For six or eight weeks he suffered most severely
from pain referred to the inside of the thigh,
extending from the pubes as low down as
within two or three inches of the inner con-
dyle of the femur, and attended with a great
deal of fever. There was no pain in the knee.
The surgeon who was then in attendance ap-
plied leeches to the hip, lotions, &c. &c., and
afterwards made an issue with caustic behind
the great trochanter. The fluctuation of fluid
was perceived at the posterior part of the hip ;
and it was supposed that an abscess had
formed ; however, no puncture was made, and
the fluid gradually became absorbed. In
March, 1825, Master L. was sufficiently well
to be able to walk about, but it was discovered
that the limb was shortened. In November,
1825, Sir B. Brodie was consulted respecting
him ; at this time there were all the marks of a
dislocation of the hip upwards and outwards,
the limb was shortened, the toes turned in-
wards, and the head of the femur was distinctly
to be felt on the posterior part of the ilium,
above the margin of the acetabulum.

Now, if we may be permitted to give an

* On Diseases of the Joints, 3d edit,
t Case XI. Brodie, page 51, 3d edition.
3F 2

788

ABNORMAL CONDITIONS OF THE IIIP-JOINT.

opinion as to this case, we would cer-
tainly question much the correctness of the
conjecture, that the inflammation of the hip-
joint was altogether limited to the synovia!
membrane: no doubt, so far' as the hip was
concerned, the inflammation began in the syno-
vial structures ; but who can doubt that in this
case the cartilages became secondarily en-
gaged, that the acetabulum itself was after a
time implicated, and that an abscess had
formed ? For our parts, we have little doubt
that all the structures entering into the compo-
sition of the articulation were implicated in the
inflammation of the joint.

It has been above stated, as the opinion of
the author now cited, that synovitis has for the
most part the form of a chronic affection, but
as a proof that a disease, apparently slight,
and of a part no way concerned in the vital
functions, may produce such a degree of dis-
turbance of the constitution as rapidly to occa-
sion death, he adduces the following case.*
Sir B. Brodie considers it a case of inflam-
mation of the synovial membrane, (synovitis
coxae,) which ran its course to a fatal termina-
tion in the short space of a week.

A young lady, nine years of age, being at
play on the 1st of January, 1808, fell and
wrenched her hip ; she experienced so little
uneasiness, that she walked out on that day
as usual; in the evening she went to a
dance, but there was seized with a rigor, was
carried home, and put to bed. Next morning
she was much indisposed, and complained of
pain in the thigh and knee ; on the following
<lay she had pain in the hip, and was feverish.
These symptoms continued ; she became deli-
rious, and died just a week from the time
of the accident. On inspecting the body on
the following day, the viscera of the thorax and
abdomen were found in a perfectly healthy
state. The hip-joint on the side of the injury
contained about half an ounce of dark-coloured
pus, and the synovial membrane, where it was
reflected over the neck of the femur, was
destroyed by ulceration for about the extent of
a shilling. This was an awful case, and such,
fortunately, are rare ; however it has been our
lot to witness some very similar in their course
and unhappy termination, and we have always
looked upon them as specimens of that terrible
disease " diffuse inflammation."

The next case, No. XVI. in Sir B. Brodie's
work,f we look upon exactly in the same light.
The following the writer saw under the care of
his lamented friend, the late Dr. M<Dowel.

Synovitis coxa with periostitis succeeding to
« fall on the hip — death in eight days. — Peter
Neale, set. 12, admitted into the Richmond
Surgical Hospital, January 11, 1833. Four
days previous to admission he fell from a wall
of moderate height, on the left hip, which was
so much contused, that he was unable to stand
upon the limb, and was carried home. The
pain and constitutional disturbance increased
•daily; on admission it was found that the left

* Case XV. p. 64, 3d edit,
t Page 6~5, 3d edition.

hip-joint was very tense and swollen ; the pain
was so excruciating that he was unable to move
in bed without assistance; his countenance
anxious, sunken, and expressive of intense suf-
fering, tongue furred, black sordes on his teeth ;
he was delirious, and screamed without inter-
mission ; his hip became more tender, tense,
and swollen ; he also now complained of pain
in the right shoulder and elbow. To these
symptoms succeeded drowsiness, tendency to
coma, occasional muttering delirium ; he now
had a peculiarly wild and frightened look.
He died on the morning of the 15th ; the
fourth from his admission into the hospital,
and the eighth from the time of the fall on the
hip. The post-mortem examination took place
four hours after death. On cutting through the
left glutaeal muscles, matter issued from nu-
merous small points ; the muscular fibres were
of a deep red colour ; the periosteum was de-
tached from the entire of the ilium by a quan-
tity of dark brown pus, which passed through
the great sciatic notch, and separated the mem-
brane from the whole concavity of the bone,
which was of a pink colour ; the fluid had
passed through a small ulcerated opening in
the capsule of the joint from the cotyloid
cavity; small portions of lymph were found on
the head of the bone, and the synovial mem-
brane, covering the fatty mass at the bottom of
the acetabulum, bore evidences of acute inflam-
mation having existed here ; and the surface of
the synovial membrane was also covered with
lymph. There was no ulceration of the carti-
lages. The right shoulder-joint healthy. In
the right elbow-joint a fluid in small quantity,
resembling that which was contained in the
hip- joint.*

Cartilage. — The inflammation and ulcera-
tion of the cartilages of the hip-joint are said by
Sir B. Brodie to be most frequently met with
in those who have passed the age of puberty,
and who are under thirty or thirty-five ; but
that they are sometimes seen in young children,
and occasionally in those advanced in life :
when the cartilage covering the bones which
enter into the articulation of the hip-joint are
affected, the progress of the case is slow; the
pain is at first trivial, the degree of lameness
slight; but as there is no effusion of pus or
increased secretion of synovial fluid, there is no
appreciable external swelling; but the pain,
the wasting of the limb, and lameness gra-
dually increase, with the spasmodic startings,
and abscess and dislocation follow, as in cases
in which the inflammation originated in other
tissues. To exhibit the disease of the cartilage
where this structure alone is engaged, we must
have some opportunity of witnessing it in an
individual who has died of some other com-
plaint. The following case well illustrates the
opinion of the first authority on such a sub-
ject.

John Catmah, 44 years of age, was admitted
into St. George's Hospital on the 29th of Sep-
tember, 1813, with pains of the lower limb of

* See Dr. M'DowelY observations in the 3d and
4rh volume of the Dublin Journal, on Synovitis, £r.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

789

the right side, extending from the hip to the
knee, and resembling the pains of rheumatism.
He attributed these pains to his having caught
cold about a month before his admission. He
laboured also under a complaint of his bowels,
of which he died on the 4th of December. On
dissection, no preternatural appearances were
discovered, except in the right hip. The cap-
sular ligament and synovial membrane were in
a natural state, the cartilages covering the head
of the femur and lining the bottom of the ace-
tabulum were destroyed by ulceration in about
one-half of their extent, and wherever the carti-
lage was destroyed an ulcerated surface of bone
was exposed ; the round ligament was readily
torn in consequence of ulceration having ex-
tended to it at the part where it was inserted
into the acetabulum. The bones possessed
their natural texture and hardness ; there was
no pus in the joint. It was observed that the
ulcerated surface of the acetabulum correspond-
ed to that of the femur, these surfaces being
exactly in contact in the position in which the
patient had remained since his admission into
the hospital.

Mr. Aston Key, from the cases he had an
opportunity of examining of ulceration of the
cartilage of the hip-joint in the early stage of
the disease, is of opinion that the ulceration of
the cartilage is preceded by inflammation of
the ligamentum teres. He adduces the follow-
ing interesting case.

A young female, who, for six months prior
to her death, had laboured under the usual
symptoms of chronic inflammation of the hip-
joint, and when the symptoms had nearly
yielded to the treatment employed, was attacked
with another disease, of which she died.

The ligamentum teres was found much
thicker and more pulpy than usual from inter-
stitial effusion ; the vessels on its investing sy no-
vial membrane were distended and large, with-
out being filled with injection. At the root of
the ligament where it is attached to the head of
the femur, a spot of ulceration in the cartilage
•was seen commencing, as it does in other joints,
by an extension of the vessels in the form of a
membrane from the root of the vascular liga-
ment. The same process had also begun on
the acetabulum, where the ligamentum teres
was attached.*

Bone. — The scrofulous affection of the hip-
joint or morbus coxae of Ford is, according to
modern writers, a specimen of strumous osteitis.
The disease, as far as the hip-joint itself is con-
cerned, commences deep in the cancellous
structure of the bones, and in general is re-
markably slow in its progress.

\Vhile the disease goes on in the cancellous
structure of the bones, before it has extended
further, and while there is no swelling, the
patient experiences some degree of pain, which,
however, is never so severe as to occasion seri-
ous distress ; it is often so slight, and increases
so gradually as scarcely to be noticed ; after a
time the external parts sympathize with those
within, and serum and coagulated lymph being

* SeeMedico-Chirurgical Transactions, vol. xviii.

effused into1 the cellular membrane, the joint
appears swollen : should the patient be a child,
it not unfrequently happens that this swelling
first attracts the attention of the nurse or pa-
rents. The swelling is puffy and elastic, with
blue veins meandring over its surface, but
though usually more in degree than in those
cases in which ulceration of the cartilage occurs
as a primary disease, it is not greater in ap-
pearance, because the muscles of the limb are
not equally wasted from want of exercise ; the
pain increases, but is not severe until matter
has formed, and the parts over the abscess have
become distended and inflamed, but then it is
immediately relieved upon the abscess burst-
ing. The skin, under these circumstances,
assumes a dark red or purple colour, the ab-
scess is slow in its progress, and when it bursts
or is opened it discharges a thin pus, with por-
tions of a curdy substance floating in it; after-
wards the discharge lessens in quantity, be-
comes thicker in consistence, and at last nearly
resembles the cheesy matter which is found in
scrofulous absorbent glands. In most instances
several abscesses take place in succession, but
at various intervals, some of which heal, while
others remain open, assuming the form of fistu-
lous sinuses, at the bottom of which carious
bone may be distinguished by means of a
probe. The principal difference which is to be
observed between the symptoms of this affec-
tion and that in which the cartilage is primarily
the seat of inflammation, is in the degree or
angount of pain which the patient endures, and
which is much greater in the latter than in
those cases where the disease exists in the can-
cellous structure of the bones. A girl laboured
under an affection of the hip-joint, in which
the nates were flattened, and an abscess had
broken on the outside of the thigh, but it was
observed she had suffered comparatively little
pain. Under these circumstances she died,
and when, says Sir B. Brodie, I was about to
examine the body, I observed to those who
were present, that there was little doubt but
that the origin of the disease would be found
to have been, not in the cartilages, nor in the
bony surfaces to which they are connected, but
in the cancellous structure of the bone. The
appearances verified this remark : the cartilages
were ulcerated and the bones destroyed to
some extent ; the latter were soft, so that they
might be cut with a scalpel, and on dividing
the articulating extremity of the femur longitu-
dinally, a considerable collection of thick pus-
was found in the neck of that bone below the
head, which either had not escaped at all, or
had escaped in very small quantity by oozing
through the cancellf which were interposed be-
tween it and the cavity of the joint. The hip-
joint wears externally the peculiar aspect of a
white swelling, and internally the anatomical
structure will be found similar. In this disease
of the joints the cancellous structure of the
bones is the part primarily affected, in conse-
quence of which ulceration takes place in the
cartilages covering their articulating surfaces.
The cartilages being ulcerated, the subsequent
progress of the disease is in many respects .the

790

ABNORMAL CONDITIONS OF THE HIP-JOINT.

same as where the ulceration takes place in
them in the first instance, flust is of opinion
that, under the influence of the disease in ques-
tion, the head of the bone becomes more volu-
minous than in the normal state, and that from
its gradual increase the cavity destined to re-
ceive it can no longer contain it ; that the cen-
tre of the eminence becomes very vascular and
softened, and presents evident traces of inflam-
mation, which Rust thinks always begins in
the membranous medullary tissue which occu-
pies the interior of the cancelli of the head of
the bone. Roche and Sanson, from whom we
have taken this account of Rust's opinion, add
that sometimes the articular head of the bone
is not changed in volume, but that the cavity
for receiving the head is filled by a swelling of
the cartilage which clothes it, and by that of
the cellular flocculi or Haversian glands.

Having stated the opinions of those who
would wish to arrange and distinguish from
each other the different morbid affections of the
hip-joint according to the different structures
they originate in, we regret to feel obliged here
to express our dissent from this arrangement,
as we find the greatest difficulty in adhering to
it practically.

VVe have no doubt but that the disease of
the hip, whether acute or chronic in its attack,
may begin by an inflammation of the synovial
membrane of the joint, and that occasionally,
particularly in scrofulous subjects, the cancel-
lary structures of the bones may be the first
seat of the local disease ; we might even yield
an assent to the opinion of some, that the car-
tilages may in rare cases be the structures first
engaged ; but if we seek for facts to convince
the mind of the truth of all such speculations,
we shall find but little that is satisfactory to
guide us. Post-mortem examinations seldom
reveal to us the state of the joint, until the dis-
ease has made great ravages, and until several
structures have been implicated ; the external
signs of synovitis, chondritis, and osteitis, can-
not, in our judgment, be distinctly recognized
in all cases in an articulation so covered by
muscles and so remote from the surface as the
hip-joint is. We feel convinced, therefore,
that in the present state of our knowledge
the effects of disease on the articulation of
the hip may be best considered under the fol-
lowing heads: 1. acute arthritis coxae; 2.
chronic strumous arthritis coxae ; 3. chronic
rheumatic arthritis coxae.

1. Acute Arthritis coxa. — The following case
presents an example of an ordinary case of acute
arthritis coxae . Daniel Reddy , aet. 1 8, a labourer,
was admitted into the Richmond Hospital on
the 1 1 th of October, 1 838. He now had all the
symptoms of a very severe attack of acute inflam-
mation of the hip-joint. He stated that he had
always been remarkably healthy until about
four weeks ago, when in consequence of having
lain for some hours on damp grass, he had a
shivering, which was succeeded by fever ; on
the following morning he had severe pain deep
behind the great trochanter ; he became so very
lame and unable to walk from the pain in his
left hip-joint, that he was compelled to keep

his bed; he also complained of pain in the
groin and starlings in the limb. When the
patient was supported as far as it was possible
in the erect position, we observed posteriorly
that there was a remarkable flatness and breadth
of the nates of the affected hip, and that its
lower fold had disappeared ; there was a gra-
dual pyriform tapering down of the hip into
the thigh, which was already much wasted ; the
pelvis itself was rotated on the spine, the left
side being directed backwards, and the spinal
column much curved forwards, rendering the
abdomen very prominent in this direction.
There was at first an apparent elongation of the
limb, which soon became flexed on the pelvis,
and so strongly adducted as to cross the median
line, if the term adduction can be so applied.
There was great heat all around the hip-joint ;
when pressure was made either on the great
trochanter or in the groin, it caused great pain
to the patient, and if the least movement was
communicated it seemed almost insupportable.
In bed he lay on the right or sound side, with
the left side of the pelvis directed backwards,
the left thigh and leg both much flexed and
directed inwards, as already remarked, across
the middle line ; he kept the limb by holding
it grasped with both hands near the knee.
There was some fulness, fluctuation, and ten-
derness on pressure over the left iliac fossa, and
shooting pain passed down to the knee. There
was constitutional fever and much general heat
of surface. To rest and active treatment by
leeching, blistering, and calomel with opium,
his symptoms yielded for a time, then he re-
lapsed, and such alternations occurred thrice,
and then all the urgent symptoms subsided.
In March his fever and constitutional distur-
bance had disappeared, and from the recovery
of his flesh and expression of countenance, we
judged that this attack had passed over, but
had left him liable to fresh and dangerous re-
turns of inflammation from the most trivial
causes, either local, such as injuries, or consti-
tutional. In April there was a shortening of
one inch and a half, the foot of the affected
limb rested on the instep of the other in stand-
ing, and in lying the knee was supported
by a cushion placed above the other knee ; ad-
duction extreme ; and although the thigh, leg,
and foot were habitually somewhat inverted,
eversion was admissible ; behind there was a
great widening of the buttock and retraction
of the trochanter major; no fluctuation of
matter could be felt about the joint, nor had
he any pain in the knee or hip.

Such, we imagine, is the more ordinary
course of acute arthritis coxae. In this case
acute synovitis followed the lying on the damp
grass; there was noticed an apparent elonga-
tion of the limb, which was of very short dura-
tion, and was succeeded by a shortening at first
very trifling, scarcely appreciable, but after a
month half an inch, and at last fully an inch
and a half. In consequence of the very decided
elevation on the dorsum ilii of the great tro-
chanter, with the habitual inversion, flexion,
and adduction of the whole limb, we might be
led to infer that in this case the articular liga-

ABNORMAL CONDITIONS OF THE HIP-JOINT.

791

ment and fibrous capsule had yielded from
ulceration, and the muscles had dislocated the
head of the femur from the acetabulum on
the dorsum ilii ; but the shortening was not
sudden, as we have known it to have been in
such cases, but gradual, nor by a careful ex-
amination of the dorsum of the ilium, and
searching deeply behind the situation of the
great trochanter, could we feel the head of the
femur where it should be, were it really dis-
located from the cavity of the acetabulum, nor
by a forced rotation inwards of the whole limb
could the head of the bone be rendered mani-
fest. Our strongest reason, however, for con-
cluding that the head of the bone is not really
luxated on the dorsum ilii is, that although
the foot may habitually be directed a little in-
wards, still the foot is susceptible of rotation
outwards to a greater extent than is compatible
with any idea of the head and neck of the
femur being thrown, as in the ordinary luxation,
on the dorsum ilii.

The following case of acute arthritis coxae
presents a remarkable example of this affection,
in which the course of the disease was rapid, its
symptoms obscure, and death occurred sud-
denly and unexpectedly.

On the llth of January, 1829, I was
requested by my friend Mr. Speedy, then
one of my pupils at the Richmond School of
Medicine, to assist him at the post-mortem ex-
amination of a grenadier, who died with a
psoas abscess rather suddenly and unexpect-
edly. The man, aged 32, had been only one
month complaining of pains about his loins
and hip-joint, and was only a few days confined
to bed. The body was thin, though not ema-
ciated^ in the inguinal region a large fluctua-
ting swelling was perceived, which evidently
extended into the abdominal cavity, and had
assumed the situation and form of a psoas
abscess. \Vhile cutting into the cavity of the
abdomen, pus was noticed to issue from some
of the veins which were divided, and particu-
larly from the epigastric. When the abdomen
was opened, we observed that the sheath of the
psoas muscle was distended as high up as the
diaphragm, and on puncturing it a quantity of
purulent matter escaped. A second abscess
was discovered in the true pelvis, which ex-
tended from the back part of the thyroid fora-
men to the sacrum, lying outside the bladder
and rectum. We next laid fully open the
sheath of the psoas muscle, which we observed
had not been organized into the usual form of
a cyst, and search was made for some point of
diseased bone along the spinal column, but
none was found here; we then directed our
attention to the hip-joint ; we found the cap-
sular ligament perfect, except where it arises
from the transverse ligament of the notch
near the thyroid foramen. Here a large per-
foration existed in the capsular ligament,
through which the finger could be passed on
through the thyroid foramen into the interior of
the abscess in the true pelvis ; the sac of this
last abscess we traced as high as the bifurcation
of the aorta and junction of the common iliac
veins with the vena cava; here this latter vessel

was found firmly adherent to the sac, and on
carefully removing both in connection, and
slitting up the vena cava posteriorly, we had a
view of a perforation in its anterior wall, close
to its junction with the iliacs; this perforation
was large enough to admit a goose-quill, and
established a free communication between the
vein and the cavity of the abscess, by which
blood and purulent matter had an easy passage
from one to the other. How long this commu-
nication had existed we could not ascertain ;
but thus was satisfactorily explained the extra-
ordinary phenomenon which had attracted our
attention in an earlier stage of the dissection,
viz. the issue of pus from some of the veins of
the abdominal parietes which were cut across.
On prosecuting the examination still further,
we found that close to the anterior inferior spine
of the ilium and iliopubal eminence, where the
united tendons of the psoas and iliacus mus-
cles pass over this part of the horizontal ramus
of the os innominatum, a vertical perforation of
the brim of the acetabulum existed, half an
inch deep, of a funnel shape, with its largest
part towards the acetabulum, and capable of
allowing at its smallest part a large sized bougie

Fig. 310.

to pass ; through this the matter had passed up
and elevated the psoas muscle or distended its
sheath, which thus presented the ordinary cha-
racters of a psoas abscess, but which we learned
had appeared suddenly and without having
been preceded by the usual premonitory signs.
There was no trace of cartilage, Haversian
gland, or synovial membrane on the acetabu-
lum; the round ligament was gone, and the
cartilaginous covering of the head of the femur
had been removed, as well as the synovial
membrane of the neck of this bone. The ex-
posed surfaces of the bones were carious, but
the acetabulum had suffered more particularly ;
it was deeper, but not wider than usual ; its
fundus, where formed by the ischium, was thin
as paper, but yet no perforation had taken

792

ABNORMAL CONDITIONS OF THE HIP-JOINT.

place in this part of the cavity, as thickened
periosteum supported the bone, while the ulce-
rative absorption was so active in the interior
of this cavity, removing the bone, osseous
spiculae or stalactiform growths, such as we are
familiar with as being produced around scro-
fulous joints, had been deposited around the
entire circumference of the acetabulum ; some
of these had much narrowed the usual extent
of the obturator foramen, at that point where
matter had passed from the joint into the inte-
rior of the pelvis. The bones have been mace-
rated and preserved in the Richmond School
Museum, and verify many of the statements
made relative to this very singular case.

What influence the communication between
the cavity of the abscess and the interior of the
vena cava had in producing the fatal result in
this case, we do not feel ourselves called upon
to determine, nor is this the place to dwell on
this obscure subject. The usual phenomena of
apparent elongation at first and real shortening
of the limb afterwards, either did not exist or
were so trifling as not to be appreciated in this
case, and the disease ran its course rapidly to a
fatal termination, the head of the bone remain-
ing in its normal position in the acetabulum.
It was probably from having witnessed such
cases as the foregoing that that experienced
surgeon, Boyer, was induced to make the fol-
lowing remark : — " On a observe un variete de
la carie qui n'attaque que le fond de la cavite
cotylo'ide ; de sorte que ce fond settlement est
detruit, tandis que ces bords restent intacts ;
alors la maticre purulente de mauvaise qualite,
qui la remplit, se porte j usque dans le bassin,
ou elle forme un foyer plus ou moins conside-
rable ; dans ce cas, la maladie fait perir le
sujet, sans deplacement du femur."

We will adduce but one example more of
the acute arthritis coxae, with the post-mortem
examination.

Alexander Clarke, set. 17, on admission into
the Richmond Hospital, it was observed that
there was much swelling about the hip-joint;
the integuments over it were tense and shining,
the glands in the groin were swollen and very
tender; he suffered from pain, shooting to the
knee and spasmodic starlings, which awoke
him at night; he could not permit the slightest
motion of the limb, which was shortened one
inch and a quarter ; it was habitually inverted
and flexed on the trunk ; the constitutional dis-
turbance was considerable. From the treat-
ment adopted he derived benefit, and a partial
recovery resulted. He left the hospital, but
soon returned, in consequence of an aggravation
of all the former symptoms, caused by a fall on
the diseased hip. A deep abscess formed in
the groin and extended under Poupart's liga-
ment; hectic symptoms showed themselves.
There were alternate diarrhoea and attacks of
vomiting. The abscess in the iliac fossa in-
creased, the tumefaction around the joint dimi-
nished, the shortening and inversion of the limb
became greater, and oedema of the foot and leg
occurred ; he now became suddenly insensible;
his left arm was totally paralyzed, while the
right was convulsed and constantly in motion ;

his face too was distorted by twitchings, and he
passed his discharges involuntarily ; he lay thus
for several days and died, being in all eighty
days ill.

Post-mortem examination. — Upon cutting
down to the hip-joint the capsular ligament was
found to have been extensively removed ante-
riorly; posteriorly and laterally it was not ulce-
rated, but seemed to have been greatly length-
ened and widened ; the synovial membrane
was lined with a yellowish-green membrane,
just like what we see investing the interior of
the sac of an old chronic abscess ; the ligamen-
turn teres and cartilage, which invested the
head of the bone, had been removed, the bones
were rough, unusually red and vascular, and
were coated with yellowish-green lymph ; the
acetabulum was much enlarged, and the head
of the bone was drawn to the upper and outer
part. The left iliac fossa was entirely filled by
an immense abscess, lying between the muscle
and bone, passing down under Poupart's liga-
ment as far as the lesser trochanter. The iliac
vessels and the anterior crural nerve were
pushed forwards ; half an inch below Poupart's
ligament a process of the abscess had passed
outwards and backwards, which communicated
with the hip-joint, and having the muscles pos-
terior tp the joint, which were thinned and
matted together, to form its wall in that direc-
tion. In the brain purulent matter was found
on the arachnoid surface as well as between the
several convolutions of the right hemisphere.
The neighbouring portion of the brain was
softened and vascular; there was no effusion
into the arachnoid sac or into the ventricles.*

Sometimes the acute arthritis coxse is an
essential disease, and the only one present at
the time in the constitution, being simple and
confined to the one articulation, as in the case
of Reddy before quoted. Sometimes, however,
the acute inflammation of the hip-joint is a
symptom of another disease. In acute rheu-
matic fever the hip-joint is, in its turn, some-
times severely visited. Finally, the cases yet
published of acute periostitis and synovitis
combined, and of acute puerperal rheumatism,
in which the hip-joint became implicated, need
not be discussed here. We are of opinion that
such cases should be looked upon as true spe-
cimens of that almost intractable disease called
diffuse inflammation.

Anatomical characters.— -From the post-mor-
tem examinations of cases of acute arthritis
coxae which have been hitherto made, we can
collect that all the structures around the joint
are in a state of active vascular congestion.
The synovial membrane and subsynovial struc-
ture present the ordinary characters of active
congestion and the results of acute inflamma-
tion. Sometimes there is an increased secretion
of synovial fluid, and sometimes, in its stead,
purulent matter distends the articulation. The
synovial membrane, where it is reflected over
the neck of the femur, has been found de-

* See Dublin Journal, vol. iii. and iv,, also pre-
paration in the Richmond Hospital Museum, which
the writer has recently inspected.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

793

stroyed by ulceration. Sometimes the purulent
matter has been known to have escaped from
the articulation by ulcerated openings in the
capsule of the joint, and to have passed into
the pelvis, and penetrated between the muscles.
The fatty mass at the bottom of the acetabulum
has been found swollen, inflamed, and covered
with a membranous layer of lymph, at the
same time in some of these cases the neigh-
bouring periosteum has been found detached
from the bone, which was redder than usual.
These are appearances which have been noticed
in those who have died of acute arthritic in-
flammation, whether it may have arisen from
diffuse inflammation or simple acute disease
confined to the one articulation. In acute
cases, actual dislocation of the bones, we be-
lieve, has not been noticed, as the disease seldom
arrives at its second or third stage under such
circumstances, but the cartilage and synovial
membranes have been altogether destroyed, and
the porous structure of the bones has been ex-
posed, digital depressions have been seen pro-
duced by acute caries in the acetabulum and
head of the femur. The bones have then pre-
sented a rough vascular surface, and in many
cases lymph has been found to cover the con-
vexity of the head of the thigh-bone and to line
the acetabulum. The head of the femur some-
times is but little altered, either as to form or
position, but when the acetabulura is largely
excavated by disease, the head of the thigh-bone
will be found to be drawn by the muscles to
its upper and back part. Even in acute arthri-
tis coxae in the young subject, the epiphysis of
the head of the femur has been found de-
tached.* The ligamentum teres is generally
absorbed early, and the capsular ligament is
usually ulcerated in some one part, so that, on
the post-mortem examination, the bones are
found to be very moveable on each other. They
are usually observed to be highly vascular, and
some imagine the head of the femur is en-
larged. Hyperosteotic depositions or stalacti-
form productions, which are very friable, exist
around the diseased joint.

2. Chronic strumous arthritis coxa. — The
scrofulous disease of the hip-joint is very gene-
rally slow in its progress, and is seldom seen,
except in persons who bear other evidences of
the strumous diathesis ; there are examples of
it occurring in individuals who have passed the
age of thirty years, though generally seen in
those of more tender years. This affection of
the joint, although slow and insidious in its
attack, yet is attended with the usual pheno-
mena of an inflammatory or sub-inflammatory
action. Many of the writers who have de-
scribed the " disease of the hip-joint," have
assigned to it three periods or stages, as Ford
has done, while succeeding authors have added
to the description of the three stages of Ford, a
period which they call the period of the inva-
sion of the disease. In this their first stage,
there is pain in the thigh, extending to the

* See a preparation in the museum of the Col-
lege of Surgeons, Dublin, presented by the late
Professor Todd.

knee, which appears and disappears alternately;
a marked weakness in the thigh, and a sense of
feebleness in the whole limb; the gait is limp-
ing, and some tension is felt in the groin. This
period lasts sometimes but a few days, at other
times many months. In the second period the
limb is wasted, and apparently, though not really,
elongated; the trochanter is placed lower down,
and is more outward than that of the opposite
side ; the buttock is flattened, and its fold is
lower than natural ; the patient's lameness is
characteristic ; he moves the affected limb
round with a shuffling motion, the foot scraping
the ground, and he sometimes assists the eleva-
tion of the thigh with his hand. At this time
the knee is painful, and not unfrequently a
puffy swelling appears in it, both which cir-
cumstances often too much attract the attention
of patient and surgeon, and divert it from the
true seat of the disease. The third period
is characterized by a real shortening of the
limb ; this is sometimes sudden, and the im-
mediate consequence of caries of the brim of
the acetabulum and luxation of the head of the
femur upward and backward on the dorsum of
the ilium. The shortening of the limb, however,
is more commonly gradual, and the consequence
of the slow ulceration and widening of the ace-
tabulum.

It has of late been truly observed, that the
luxation is not so common as generally ima-
gined, but when it does occur, it usually takes
place in the direction upwards and outwards ;
when the fibrous capsule and other ligaments
are destroyed by ulceration, the head of the
femur escapes by the superior and posterior
part of the acetabulum, and obeying the action
of the glutaei muscles, it glides from before
backwards and without inwards upon the con-
vex surface of the ilium ; the thigh is flexed,
adducted, and turned with a strong rotation in-
wards ; the great trochanter approaches the
crest of the ilium, the muscles are raised up by
the head of the femur, and the buttock is
rounded, and becomes very protuberant poste-
riorly. Although this is the direction in which
the luxation usually takes place, still it has
been noticed to have occurred in a direction
horizontally backwards towards the ischiatic
notch (Earle). It has also been seen in the
direction downwards and inwards towards the
foramen ovale, in which case the limb is elon-
gated and directed outwards. Still more rarely
has it been thrown upwards and inwards on the
horizontal ramus of the pubis. In one in-
stance, says Brodie, I have seen the dislocation
in the direction forwards, the head of the femur
resting on the pubis, the knee and toes being
turned outwards.

It would be wrong, however, to suppose that
a true dislocation of the head of the femur
from the ulcerated acetabulum is a very com-
mon occurrence; although all these cases,
above alluded to, have been witnessed, we be-
lieve very frequently the shortening of the limb
in the third and fourth stage of the disease
arises from ulceration and widening of the ace-
tabulum and destruction of the head of the
femur. The head of the femur sometimes sepa-

794

ABNORMAL CONDITIONS OF THE HIP-JOINT.

rates at its epiphysis from the neck of the bone,
and the latter is drawn up, (Jig- 311,) and the

Fig. 311.

whole limb shortened greatly, and the toes are
as much everted as when fracture of the neck
of the femur occurs from accident. The short-
ening is usually, but not invariably, the pre-
cursor of abscess; when this occurs, the disease
is in its fourth stage. This period, or that of
of the formation of matter, is generally marked
by an aggravation of the pain, by frequent
spasms and starlings of the muscles, by greater
wasting of the limb, occasional oedema of the
foot, (which is a very unpromising feature,)
&c. These chronic symptomatic abscesses may
present themselves in various directions ; the
matter may remain for months without under-
going any change, and even after this be rather
suddenly absorbed, or the pus may escape
through openings made by nature or by art ;
the external orifices of these abscesses frequently
degenerate into fistulae, from which exfolia-
tions occasionally take place, and these exfolia-
tions are sometimes so small as to be almost sabu-
lous, sometimes larger pieces come away with
pain ; such are to be considered not unfavoura-
ble indications. The writer has known two ex-
amples of the head of the femur thus separated at
their epiphysis from the neck of the bones ; in
these cases the patients recovered, with the usual
deformity.* Of the numerous situations around
the hip-joint, in which matter has been found
deposited, there is one variety which demands
the special attention of surgeons, in conse-
quence of the difficulty which has been expe-
rienced in recognizing the disease, namely, the
case in which the caries affects the bottom of
the acetabulum, so that the fundus alone is de-
stroyed. Sir B. Brodie met with one case,

* One of these was presented to him by Mr.
Shaw, the surgeon to the Clonard Dispensary, and
is preserved in the Richmond School Museum ; the
other was shewn by Dr. Carlile lately to the Patho-
logical Society, Dublin,

where in the bottom of the acetabulum there
was an ulcerated opening, just large enough to
admit a common probe, communicating with
an abscess within the pelvis. Mr. Tagart*
alludes also to a case in which this perforation
exists. ( Figs. 312 and 313.) Of such per-

Fig. 312.

* Lancet, vol. i. 1835 and 6, Jan. 2.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

795

forations the writer has seen in different mu-
seums a great variety: in many instances the
opening is small, in others of sufficient size to
admit easily the head of the femur. These
cases are in the beginning obscure, and when
abscesses form, they are concealed within the
cavity of the pelvis.

Anatomical characters. — When opportuni-
ties have occurred of examining the interior of
the hip-joint in those who hare died of other
complaints, this articulation being, at the time
of death, in the early stages of the chronic dis-
ease we are now considering, the adipose
cellular mass which occupies the fundus of the
acetabulum, the cellular structure which con-
nects the fibres of the inter-articular ligament,
the subsynovial cellular tissue which surrounds
the corona of the head of the femur, as well as
the interior of the bones themselves, have been
found to wear an unusually red appearance
from increased vascularity. The cartilage has
been found softened, to have lost its usual
lustre, to be slightly elevated, and too easily
torn from the subjacent bone ; in some cases
thinned, in others detached in flaps; in some
it has presented a corroded appearance, and
coinciding with these changes purulent matter
has been found in the interior of the joint, the
capsular ligament thickened, and the lymphatic
glands in the groin enlarged. In the anatomi-
cal examination of those who have died in the
advanced stages of the scrofulous disease of the
hip, if the patient have not arrived at the age
of puberty, we find that very frequently the
original portions of the os innominatum are
separated from each other for several lines, that
the epiphysis of the head of the femur is com-
pletely detached from the shaft of this bone ;
the greater and lesser trochanters are sometimes
in very young subjects removed by absorption,
and evidence of devastating caries is found in
the bottom of the acetabulum. ( Fig. 311.)

In some cases the head of the bone has been
found dislocated on the dorsum ilii, previous
to which occurrence all the ligaments have been
destroyed, the acetabulum has the superior and
posterior part of its brim removed by caries,
and the bone thus abandoned to the action of
the muscles takes the position it ordinarily
does in the common luxation upwards and
backwards on the dorsum ilii. This complete
dislocation is not so common an occurrence as
generally imagined ; there are, however, some
specimens of it preserved in the museum of the
College of Surgeons in Dublin. In one pre-
paration, the cartilage of the head of the femur
is perfect, the round ligament is gone ; the fur-
ther ascent of the head of the bone on the dor-
sum ilii seems principally restrained by the ob-
turator muscles (Jig. 314). The interesting
circumstance in the preparation to be noticed
is, that the acetabulum is occupied to the level
of its brim with a very dense atheromatous
matter or yellowish green lymph, apparently an
unorganized substance resembling what we see
contained in crude scrofulous tubercles : what
remained of the capsular ligament around the
neck of the femur has been cut crucially, and
the everted edges of the flaps shew th« thick-

Fig. 314.

ness of this ligament, increased to four or five
lines, and caused by the interstitial deposition
of something like atheromatous matter.

We have in the foregoing pages alluded to
the different directions in which the head of the
femur has been found dislocated in the third or
fourth stage of this disease, and should here
state the anatomical characters of each luxation,
but we have not facts to guide us in the de-
scription.

When a section is made of the bones enter-
ing into the composition of the hip-joint, when
the patient has died of this disease in an ad-
vanced stage, they will be found to be softened
in the interior, and to contain a fatty or a yel-
lowish cheese-like matter in their cells ; when
opportunities have occurred for examination in
an earlier stage of this scrofulous caries, these
organs have been generally found preternatu-
rally red and vascular, (as before stated,) with
a deficient proportion of earthy matter, admit-
ting not only of being cut with a knife without
turning its edge, but yielding and being crushed
under very slight pressure. A modem au-
thor,* after quoting the authority of Lloyd on
scrofula as proof of the truth of some of the
foregoing observations, adds his own opinion,
" that in simple inflammation, uninfluenced by
the scrofulous diathesis, particularly when it
becomes of a chronic character, bone is secreted
in abundance, but that the striking feature
in this kind of inflammation is, the absence of
all secretion or deposit of bone." With the
latter doctrine we cannot at all agree, and must
conclude we do not rightly apprehend the

* Coulson on the Diseases of the Hip-joint,
Loud. 1837, 4to. p. 39.

796

ABNORMAL CONDITIONS OF THE HIP-JOINT.

author, as we have very generally found osseous
growths exterior to the hip-joint in the os inno-
minatum and femur, (fig. 310), as the result
of scrofulous inflammation of the articulation.
These growths are generally friable stalactiform
productions which beset the bones, and are to
be seen in the numerous specimens illustrating
the morbid anatomy of morbus coxae, which
are contained in our museums in Dublin.*
Notwithstanding these osseous productions or
vegetations, the bones are found to have dimi-
nished much in their specific gravity. I have
always found them float when thrown into
water. These growths are, however, only met
with in the post-mortem examination of such
chronic cases as have manifested in their course
various alternations of improvement and re-
verses ; they are almost invariably found when
the caries of the bones had been arrested, and
an imperfect attempt at anchylosis had been
made.

We have also opportunities of examining
anatomically the hip-joints of persons who have
had this disease in their youth, in whom it had
been arrested in the second or third stage, and
•who had attained advanced life, and died of
some other complaint. In some, besides the
bony growths already alluded to, we find ex-
amples of anchylosis or of a false joint ; indeed,
although an absolute union and consolidation
of the bones, viz. the os innominatum and
the head of the femur may not have taken
place, still in most cases there is very little
real motion of the two bones upon each other ;
the flexor and adductor muscles of the thigh
and hip-joint are usually in a state of spastic
contraction ; they admit of but little increase
of flexion: whenever we attempt extension, we
find the thigh is readily brought down from
the abdomen, the lumbar vertebrae are arched
forwards, and this portion of the spine and the
sacrolumbar articulation are the seat of motion,
which often is erroneously referred to the hip-
joint. The os innominatum follows the head
of the femur just as freely almost as the scapula
accompanies the various changes of position
impressed upon the humerus, when anchylosis
of the shoulder-joint has taken place. I was
called upon about eight years ago to examine
the body of a woman, aged 26 years, who died
in the Whitworth Hospital of an acute disease.
This young woman had walked very lamely for
many years, in consequence of her having had
a most tedious and dangerous attack of hip-
disease twenty years before her death, but after
her recovery from the first attack she never had
any pain or inflammation in the joint ; there
were no evidences of suppuration ever having
occurred ; marks of issues were on the nates.
When making an examination of the struc-
tures around the articulation and of the joint
itself, the muscles were found remarkably
firm, but somewhat paler than usual ; the
ligamentous structures around the junction of

t These osseous vegetations we have already
.alluded to in this work, when speaking of the chro-
nic strumous arthritis of the elbow : see p. 79,

ELBOW-JOINT, ABNORMAL ANATOMY OF.

the femur with the os innominatum were very
strong, and so close was the union of the bones
that on a superficial view we might easily ima-
gine that true bony anchylosis had occurred.
I removed the bones, and they are preserved in
the Richmond School Museum. The whole
head of the femur has been absorbed, and only
one-fourth part of the neck of the bone remains ;
the place of the cotyloid cavity is supplied by
a rough scabrous surface, of an oval form trans-
versely, and about one inch and one line in this
its longest diameter ; the two rough bony sur-
faces with eminences and depressions con-
fronted to each, and reciprocally adapted, were
joined by a species of strong fibrous capsule ;
no motion whatever existed between these
bones, yet when the ligamentous connexion
between them was cut, it was evident that no
bony union had taken place. In this case the
false anchylosis had occurred in a very unfa-
vourable direction ; the thigh was flexed to so
great a degree that the knee was really elevated
above the level of the hip-joint, and so much
adducted at the same time, that the knee crossed
much the middle line. When she stood up
straight on the right and perfect limb, the left
heel did not approach within twelve inches of
the ground : the texture of the bones was as
hard as iron.

We find in a modern author the observation,
which must be admitted to be correct, that true
bony anchylosis of the hip-joint is rare ; but,
he adds, that many pathologists doubt that
such an occurrence ever takes place : that the
many specimens of true bony anchylosis of the
hip we have witnessed, were all examples of
union of bony surfaces in scrofulous cases, we
would not wish to maintain, but we imagine
many of them must have been the result of the
ordinary hip disease cured, as it is called, by
anchylosis. Sir Philip Crampton has shewn
me a very fine specimen of anchylosis of the
hip- joint, which very much resembles the pre-
paration represented (fig. 312); the acetabu-
lum had been the principal seat of the disease;
it was much widened, and the head of the bone
was drawn towards its upper and outer part,
where firm anchylosis had taken place. In
this case Sir P. Crampton assured me the pa-
tient had a constitution eminently scrofulous.
He got well of the hip-disease by anchylosis,
the thigh-bone having been judiciously pre-
served in a vertical direction during the pro-
gress of the cure. He walked afterwards tole-
rably well, but at the age of 26 became at-
tacked with phthisis, and died. This case
proves that true bony anchylosis can occur in
the scrofulous subject, and that attention may
occasionally overcome the disposition to exces-
sive flexion and adduction of the limb.

The museum of the Richmond Hospital
contains three specimens, in which the junction
of the os innominatum with the femur is as
solid as if they formed but one bone, and a
vertical section through the united bones shews
as free a communication of the cells of the
cervix femoris and those of the os innominatum
as if these bones had never been separately
formed. These seem to have been examples

ABNORMAL CONDITIONS OF THE HIP-JOINT.

797

of early affections of the hip-disease, in which
little or no displacement of the head of the
femur occurred.

The acetabulum, we know, is generally
widened in this disease, and the head of the
femur is drawn upwards and outwards; if at
this period the inflammation be arrested, true
bony anchylosis may occur ; and if a happy
direction can be given to the shaft of the femur,
a very useful limb may remain, even though
the hip-joint itself has lost all motion ; the
sacro-lumbar joint and the neighbouring inter-
vertebral structures admit of much freedom of
motion.

In examining anatomically the hip-joints of
those who, having had the chronic scrofulous
disease of this articulation in their youth, and
have recovered and lived for years, though
lame, in these, instead of anchylosis, we find
a false joint is formed. Of this imperfect cure
of hip disease we have seen some examples,
and we possess one remarkable specimen of it.
In this the acetabulum was altogether removed,
and a triangular space, encircled by a rounded
brim covered with a compact stratum of bone,
existed. The removal of the neck of the femur
was so complete that a plane or rather concave
surface corresponded to the inner side of the
trochanter major, from which the neck of the
bone naturally arises.

It has been stated that luxation on the dor-
sum of the ilium sometimes happens as a con-
sequence of chronic disease of the joint; some-
times the disease which carried away, in this
instance, the borders of the acetabulum, seems,
as it were, to have been transferred to the new
surface of the os innominatum with -which the
head of the femur came in contact, and we find
the process of ulceration has even continued its
course; again it sometimes happens that an-
chylosis or a false joint has been formed.

Albers and Rust have described the change
which the bones of the pelvis undergo in their
form and situation. The pelvis, in those who
have for a long time gone lame, is pushed up-
wards, and the sacrum is flat and straight. In
a few cases, however, it is more curved than in
the natural state ; the coccyx is bent strongly
forwards, and the connexion of the last lumbar
vertebra with the sacrum forms a right angle ;
the ilium of the affected side stands higher, and
has in general a perpendicular direction, and
more of a triangular form ; the external surface
is smooth, whilst the iliac fossa appears more
hollowed than usual ; this hollowing probably
depends on the action of the iliacus internus,
which is greater than that of the gluttei. The
horizontal ramus of the pubes often seems
lengthened and lower than in the natural state,
and the ischium is usually drawn outwards
and forwards ; the perpendicular direction of
the foramen ovale is changed more to a hori-
zontal one, and the opening assumes more of a
triangular form, its base being turned towards
the acetabulum. In consequence of the
changed situation of the bones of the pelvis, its
different diameters undergo an essential devia-
tion from the natural state, the superior aper-
tures of the pelvis are commonly somewhat

oblique, and the pelvis is broader on the affected
side from before backwards.*

The muscles in advanced cases are in a state
of atrophy, of a greenish hue, and often matted
together; sometimes they form the walls of
scrofulous symptomatic abscesses, containing a
thin serous pus mixed with flakes ; sometimes
the pus is inodorous, of ordinary character.
Usually the contents of the abscess make their
way to the skin, more rarely to the mucous
surfaces. In more advanced cases these ab-
scesses are found to contain fetid air and puru-
lent matter of a very bad quality ; in these
latter circumstances we discover either an ex-
ternal or internal fistulous opening ; the walls
of the abscesses have collapsed, and have been
converted into fistulous canals lined by false
membranes ; these have become, as it were, the
excretory canals, through which the matter has
been discharged from the interior of the dis-
eased joint, and through which sabulous mat-
ter, small hard pieces of bone, or pieces as large
as the epiphysis of the head of the femur, as
elsewhere noticed, have made their way. The
abscesses are found, on dissection of those who
have died of morbus coxae stramosae, pointing
or to have opened in various directions.

We have already stated that the capsular
ligament has been found perforated by fistulous
openings, and that in the advanced stage of the
disease little or no vestige of the capsule is left.
The abscesses, therefore, we meet with on dis-
section may be considered as reservoirs for the
matter which proceeds from the carious bones ;
occasionally, no doubt, we shall find around
the joint abscesses which have no communica-
tion whatever with the diseased articulation : not
only in the soft parts around the joint have we
met with such isolated collections of matter,
but also in the body of the os ilii, and in the
centre of the trochanter major of the femur.

We have given an account of an acute case
of morbus coxa?, in which a psoas abscess was
found to have originated in a carious hip-joint.
The communication of the carious bones with
the interior of the sheath of the psoas took
place through a small perforation in the hori-
zontal ramus of the os innominatum. In this
case also an abscess existed in the true pelvis,
and death was the consequence of it, having
burst into the vena cava. In Mr. Listen's
collection there is a specimen shewing ex-
tensive destruction of the acetabulum, head
and neck of the femur, with several sinuses
leading from the joint, and one in particular
of large size, leading towards the rectum
through the foramen ovale ; there is also the
rectum corresponding to this preparation, with
a rounded opening sufficient to admit the point
of the little finger, about an inch and a half
above the anus. In this case the abscess lay
across the pelvis ; by one of its extremities it
communicated with the diseased hip-joint
through the foramen ovale and ulcerated cap-
sular ligament, and by its posterior extremity
with the rectum. The case of pelvic abscess
I have so often adverted to was very similarly

* Coulson, p. 42.

798

ABNORMAL CONDITIONS OF THE HIP-JOINT.

situated, but instead of opening by its posterior
extremity into the rectum, its fundus was ele-
vated somewhat higher in the pelvis, and burst
into the vena cava. The late Dr. M'Dowel, in the
fourth volume of the Dublin Journal, says that
in two cases of hip-joint disease he had seen
several years since, the matter had passed into
the pelvis through the bottom of the acetabu-
lum, and there accumulated in such quantity
as to compress the bladder and cause retention
of urine, requiring the daily use of the catheter.
He also adds, that this route for the matter is
not uncommon, and in its progress that it may
form a tumour of considerable size by the side
of the rectum, and occasionally burst into the
cavity of this intestine. Sir A. Cooper men-
tions the latter occurrence in one instance. Dr.
M'Dowel adds, I had an opportunity of wit-
nessing it. Abscesses take their course from
the diseased joint into the pelvis, and open into
the vagina. Sir B. Brodie mentions a case of
this kind in a child aged 11 years; and in
Dr. Kirby's collection, which he presented
to the College of Surgeons, is a similar ex-
ample. Dr. M'Dowel, in the paper already
alluded to, observes that he is not aware of its
being recorded that an iliac abscess may result
from a caries of the hip-joint, yet in four cases,
he adds, I have found it to occur. The fluid
escaping through an opening on the inside of
the capsular ligament, passes upwards behind
the psoas and ascends into the iliac fossa, de-
taching the muscles from the bone. In such
cases we have considerable fulness in the groin,
which can be traced upwards behind Poupart's
ligament ; from the stretching of the filaments
of the anterior crural nerve more neuralgic pain
attends this case than we usually find in disease
of the hip-joint. The iliac vessels are dis-
placed, become flattened and adherent to the
sac ; from the compression of the vein much
more oedema of the limb is present than in or-
dinary cases. The ccecum or the sigmoid flex-
ure of the colon may be considerably displaced
or united to the sac.* Sometimes it passes
behind the vessels, and accumulating, it may
compress the bladder and rectum, which then
form the inner wall of the abscess.

In a very interesting case of iliac abscess
which was treated in the year 1833 in the Rich-
mond Hospital, ulceration of a portion of the
ilium adhering to the wall of the abscess oc-
curred, and its contents, after being poured into
the abscess, escaped externally through a fistu-
lous opening near the spine of the ilium ; ulce-
ration also of the external iliac artery took place
about an inch and a half above Poupart's liga-
ment, and sudden death resulted from the
blood escaping in large quantity into the cavity
of the abscess. The preparation is preserved
in the museum of the Richmond Hospital.
The anterior and crural nerves are often found
on the stretch. We have already mentioned a
case of this kind, (Clarke,) and Sir B. Brodie
mentions one in which he found two enlarged

* The matter, which is generally prevented from
passing down into the true pelvis by the connexion
of the fascia iliaca, sometimes makes its way into
this cavity by ulceration of this fascia.

lymphatic glands, each the size of a walnut,
immediately below the crural arch in the fore
part of the joint, and these lay in contact with
and immediately behind two branches of the
nerves, so as to keep the latter on the stretch, like
the strings passing over the bridge of a violin.

We must not forget that the diseased action
in these cases of chronic strumous arthritis is
not confined to the joint. We have seen ex-
amples in the living and specimens in mu-
seums, proving that at the same lime both hip-
joints may be engaged in the same individual.
In acute cases we have given an example of the
membranes of the brain having been affected,
so also in chronic cases; tubercles have also
been found in the lungs, the mesenteric glands
extensively enlarged, and ulcers in the intes-
tines, and tubercular accretions in the perito-
neum.

3. Chronic rheumatism. — (Morbus coxa
senilis, or chronic rheumatic arthritis of the
hip.) By these terms we would wish to de-
signate a very peculiar disease of the hip-
joint, the morbid results of which are now pretty
well known: to pathological anatomists ; but it
must be confessed that very little has been
done to make the profession acquainted with
its symptoms or appropriate treatment.

History of the disease. — We will venture to
assert that there cannot be a more graphic il-
lustration given of this disease and its conse-
quences than those to be found in the Museum
Anatomicum of Sandifort, who has not confined
his delineations to the head and neck of the
thigh-bone, but has also shewn the various
alterations of form which the acetabulum un-
dergoes.* For many years this disease has
been accurately described in the clinical lec-
tures delivered in the different hospitals in
Dublin, and the importance of distinguishing
it from the other affections of this articulation
has been pointed out. Mr. Benjamin Bell, in
his work on the bones, has, under the head of
" interstitial absorption of the neck of the
thigh-bone," alluded to this disease, and detailed
many of its external signs, as well as the mor-
bid changes which the neck of the bone suffers ;
and in the sixth volume of the Dublin Journal,
Mr. Smith, in a paper on the diagnosis of in-
juries of the hip, has given a very good and
concise account of this remarkable affection of
the hip-joint.

The writer of this article long ago, in his
lectures, gave the name of morbus coxa seni-
lis to the disease in question, but as he has
since met with many instances of it occurring
so early as at the age of thirty or forty, he is
now disposed to substitute for this name that of
chronic rheumatic arthritis of the hip-joint,
and he considers it as the same disease pre-
cisely as he has elsewhere in this work described
as affecting other articulations. (See ELBOW,
HAND, KNEE, SHOULDER.)

As to the cause of this chronic disease of the
hip-joint, we believe little is known. We
have heard it frequently attributed to the effects
of cold and wet ; and an acute attack of rheu-

* Mus, Anatom. Lugduni Batavorum, 1793.
vol. ii. tab. Ixix. ad Ixxiii.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

799

matic arthritis of the hip-joint produced by
cold, we can easily conceive may occasionally
merge into the chronic affection we wish to
describe. We have also reason to think that
falls upon the great trochanter have given rise
to the first symptoms of this disease ; but in
many cases no satisfactoiy cause can be assigned
by the patient for the origin of the affection.

Symptoms, SfC. — The patient complains of
stiffness in the hip-joint and about the great
trochanter; also of a dull boring pain which
extends down the front of the thigh to the
knee. The stiffness is most felt in the morning
when the patient commences to walk ; but
after exercise the movements of the joint be-
come somewhat more free. In the evening
of a day the patient has had much walking
exercise, the pain is always more severe. The
uneasiness, however, gradually subsides after
he has retired to bed. The pain is always in-
creased when the patient throws the weight
of his body fully on the affected joint. But
let the surgeon press on the great trochanter,
or adopt any other expedient so as to push the
head of the bone even rudely against the ace-
tabulum, and these manoeuvres are the sources
of no uneasiness whatever to the patient. Al-
though we can easily satisfy ourselves that no
actual anchylosis exists, still it is evident
enough that the motion of rotation is lost, and
that the other movements, particularly flexion,
are confined within very narrow limits. When
we place the patient in a horizontal position,
and endeavour to communicate any of these
movements to the hip-joint, the patient com-
plains of pain, and an evident crepitation can be
heard and felt deep in the articulation. The limb
is apparently shortened by from two to three
inches ; the apparent shortening arises from the
obliquity of position of the pelvis relatively to the
spine, and the elevation of the affected side is
such that the crest of the ilium and the last short
rib approach nearer to each other at this side
in the ordinary attitude of standing by two
inches than those of the opposite side. All
these circumstances account for the apparent
shortening of the limb, which however, on
accurate measurement, will be found not to be
really shortened more than an inch. The patient
walks very lame, and with the foot and whole
limb greatly everted. The nates of the sound
side is unusually prominent, while that of the
affected side is quite flat, and no trace of the
lower fold of the glutseus is seen. The mus-
cles of the thigh also seem somewhat atrophied,
still they do not want for firmness ; and we
may uniformly observe that the calf of the leg
of the affected limb is not inferior in size and
firmness to the other. When we minutely
examine the great trochanter, we find it larger
and more prominent than usual ; and about the
situation of the acetabulum, horizontal branch
of the os pubis, and lesser trochanter, bony pro-
tuberances can, upon careful examination, be
recognized. This disease, when once fully esta-
blished in the hip-joint, rarely or never extends
itself to the other articulations. We have
known, however, a few examples in which it
affected both hip-joints in the same individual.

The chronic inflammation of the various struc-
tures of the joint in which the disease consists,
is never accompanied by any appreciable de-
gree of heat or external swelling of the soft
parts, and we have never heard of the inflam-
mation going on to suppuration.

The following case will shew the necessity
of making the profession fully acquainted with
this disease, as it proves how very obscure are
the early signs of the affection, and that even
the morbid appearances may be confounded
with those which are the result of accident.
At the meeting of the British Association in
Dublin, in the year 1836, one of its most dis-
tinguished members, Mr. Snow Harris of Ply-
mouth, made the following communication to
the medical section : — " Sir A. Cooper and
many other eminent surgeons had doubted the
possibility of union taking place in fracture of
the neck of the thigh-bone, within the capsular
ligament. A case had lately fallen under his
(Mr. H.'s) notice, which he thought would
tend to set the question at rest. It was that of
a gentleman who had received an injury by
being thrown from his gig ten years ago. He
had got up and walked immediately after the
accident, but continued lame from that period
up to the time of his death. He had been at-
tended by some of the most celebrated surgeons
in London, but they had not been able to de-
termine whether there was a fracture of the
bone or not, but kept him lying on a sofa for
nearly twelve months. The injured limb was
shortened, the foot everted, the thigh wasted,
and owing to the constant inclination of the
body forward on one side, a lateral curvature
of the spine took place. Some time ago the
gentleman died of disease of the heart; and
Mr. Harris, being anxious to examine the
parts, removed the acetabulum and a portion of
the thigh-bone, which he then presented for
the inspection of the meeting. He had found
the trochanter higher up than natural, and the
neck of the bone shortened ; a section of the
bone had been made, and the line of union, in
Mr. Harris's opinion, was clearly manifest." *

When Mr. Harris exhibited this specimen to
the medical section of the British Association
which met in Dublin, it excited much interest,
first as the individual, the subject of the case,
was the celebrated comedian Mr. Matthews,
and secondly, as at the announcement of the case
it was asserted that it settled in the affirmative
the much agitated question, whether the intra-
capsular fracture of the cervix femoris was or
was not susceptible of osseous union. The
writer was present at the communication of this
case to the section, and upon the presentation
of the specimen expressed his doubts that this
case, either from its history or post-mortem
appearances, was an example of the intra-cap-
sular fracture, and rather held the opinion that
it was one of this chronic rheumatic affection
which he has been endeavouring to describe ;
in which opinion he was most decidedly con-
firmed upon inspecting the acetabulum, the
widening of this cavity, the complete filling up

* See Dublin Journal, vol. viii.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

800

of the fossa which is normally destined to con-
tain the substance called Haversian gland, the
shortening of the neck of the femur and depres-
sion of the head towards the lesser trochanter,
and the ivory deposition on it. In this view Mr.
Smith, who had so well described the disease in
question, and the hospital surgeons around him,
concurred, and Mr. Snow Harris himself quickly
became a convert to our views, and we are sa-
tisfied from what we observed of his liberality,
thatwe have his full permission to communicate
this case in its present form to the profession.
The sketch (jig. 315) is taken from the cast of the

Fig. 315.

Fig. 316.

Mr. Siww Harris's case.

head and neck of the femur presented by Mr.
Harris to the College of Surgeons, Dublin. The
upper part of the head of the femur was exceed-
ingly rough on its surface, and of an oval form
from above downwards ; the axis of the neck
was at right angles with the shaft, and seemed
to run horizontally inwards and backwards, so
that the length of the fossa which exists poste-
riorly between the corona of the head and the
posterior inter-trochanteric line, was in this case
less than a quarter of an inch, a fossa which
we know naturally measures two inches. In
viewing the oval form of the head, we conclude
the movement of rotation must have been im-
possible ; from the shortening of the neck pos-
teriorly, we can infer that the toe and foot must
have been greatly everted, and from the depres-
sion of the head, to the level of the trochanter,
the femur must have been nearly one inch
shorter than the other. The lamented indivi-
dual had not suffered from the disease more
than ten years, so that the morbid appearances
were not to the same amount as we are accus-
tomed to see as the result of this very slow dis-
ease.

The following case is that of an individual
who has been, to the writer's knowledge, suffer-
ing for many years under this disease.

Patrick Macken, now aged seventy-seven
years, was brought up as a postilion and groom,
but for the last seventeen years has been quite
unfit for service in consequence of his having
been afflicted with a very severe pain in his
right hip ; from the first attack of which he be-
came lame, and ever since the lameness has
been slowly but gradually increasing. In every

Chronic rheumatic arthritis of the Hip.

other respect his health is excellent, except that
he has some wandering rheumatic pains in other
joints, particularly in the right shoulder.

He walks with great labour and pain, and now
requires the assistance of a stick in each hand (Jig.
316); in the morning his movements are stiff and
confined, but they become freer on exercise; in
the evening of a day he has walked much, the pain
and stiffness are worse and increased in propor-
tion to the excess of exercise and labour he had
undergone in the day. While he remains in bed
he rests on the affected hip, and suffers no pain
whatever except he suddenly turns himself in-
cautiously. As soon as he gets up and throws his
entire weight on the diseased hip-joint, the pain
commences; if asked in what particular part of
the joint he feels most suffering, he points to the
back part of the great trochanter and to a point
which corresponds to the situation of the lesser
trochanter ; he says the pain shoots from these
points down the front of the thigh to the knee.
These pains are sometimes more severe, and
sometimes less, without his being able to as-
sign any cause for these alterations, and he can-
not observe that the state of the weather has any
influence on them whatever.

As he stands at rest, he throws the weight
of his body on the left or unaffected limb,

ABNORMAL CONDITIONS OF THE HIP-JOINT.

801

while the right leg hangs in front and slightly
across the left, and seems to be at least three
inches shorter; he leans slightly back and
supports himself on two sticks : as he walks
the right foot is considerably everted, and when
he moves without sticks (which he accomplishes
with the greatest difficulty) he places the whole
sole of the foot flat upon the ground. He
never, however, ventures of his own accord to
move without the help of two sticks, by the assist-
ance of which he is enabled to walk quicker;
while moving along thus, the heel of the
affected limb does not quite reach the ground,
and the lumbar vertebrae undergo great motion.
He cannot under any circumstances flex the
thigh on the abdomen, so that when he assumes
the sitting posture, he is obliged to place him-
self forwards on the very edge of the seat, the
right thigh remaining in the same line as the
axis of the trunk, the leg usually flexed and
placed under the chair, or across behind the
other, and he finds the utmost difficulty in
putting on his stockings and shoes. He has
scarcely any motion in the hip-joint. When
we view the hip in front, and examine it, we
see and can feel a considerable bony fulness,
corresponding to the horizontal branch of the
pubis : the trochanter major seems placed very
high up, and is extraordinarily large as if sur-
rounded with ossific deposits. The thigh is
somewhat atrophied, being an inch and a half
less in circumference than the other, but the
calf of the leg is not reduced, and the muscles
seem firm ; the apparent shortening of the limb,
when he rests on the sound one, arises from the
lumbar vertebra being much curved to the oppo-
site side, and the pelvis being elevated on the
affected side, while the real shortening ascer-
tained by accurate measurement amounts only
to half an inch.

If we place the patient horizontally and
attempt to communicate to the hip-joint any
movement, as of rotation, flexion, abduction, a
well-marked crepitus is elicited, and the range
of motion is found to be very limited indeed ;
a little abduction is admitted ; rotation and
flexion seem just to a sufficient degree to
shew that no anchylosis exists. The move-
ments give some pain to the patient, but we
can press the trochanter firmly so as to direct
the head of the bone deep against the fundus
of the acelabulum, and we can even strike the
heel and sole of the foot with violence without
giving the patient the slightest sensation of pain.
The anatomical characters of this disease
are very well marked. The muscles are usually
of a paler colour than natural, and are found
not to be so well developed as those of the
opposite or sound hip. The fibrous capsule
of the joint is greatly thickened, the cotyloid
ligament is either ossified or absorbed, and
the ligament which completes the notch, and
in the natural state gives origin to the liga-
mentum teres, is usually converted into bone,
leaving generally beneath its arch whether
bony or not a space for the transmission of
bloodvessels to the interior of the joint ;* when

* Cravcilhier, livraison iv. p. 1. La presence
VOL. ii.

the disease is fully established the ligamentum
teres is altogether removed, the synovial fluid
is deficient in quantity, and the cartilage is
removed from the bottom of the acetabulum,
and upper surface of the head of the femur. If
here and there some vestige of the synovial
membrane or sub-synovial tissue remain, it is
in a highly vascular condition, presenting an
intensely red colour. In a case of dissection
which Messrs. Smith, Brabazon, and the writer
witnessed lately of this disease, we observed
that the shortened neck of the femur was
entirely surrounded with a number of red
villous - looking productions of the synovial
membrane. These were of a rounded and
conical form, half an inch long and two or
three lines broad at their bases. They resem-
bled much in form the long conical papillae to
be seen on the tongue and about the fauces
of herbivorous quadrupeds ; however, instead
of being white and firm they were soft and
villous, and of an intensely red colour. The
line of the corona of the head was absorbed and
excavated in points, and the different foveae or
depressions were completely occupied by these
vascular fimbriae. Still more recently the wri-
ter met with a similar specimen which he pre-
sented for inspection to the Pathological So-
ciety, in which these vascular fimbrise were
equally conspicuous.*

The acetabulum is generally much larger
and deeper than natural, and forms a circular
cup often two inches deep with a complete level
brim, which is sometimes so much narrowed as
to render the extraction of the head of the
femurdifficult. This is the most frequent abnor-
mal appearance the acetabulum presents ; but
occasionally it is increased in size, and is at the
same time very shallow and of an oval form.

When we examine the bottom of the acetabu-
lum we find it widened and not any trace of
Haversian gland is left ; the interior presents a
worn and porous appearance, the cartilage and
compact stratum of bone which the cartilage
normally covers, having been removed, and in
some places where the friction and pressure
from the head of the femur have been greatest,
instead of a rough and worn porous appearance,
resulting from the exposure of the cells of the
bone, a dense enamel has been as it were
ground into these pores, and here the surface
presents the polish, smoothness, and hardness
of ivory. This mechanical removal of the carti-
lage and exposure of the interior of the cells of
the bone, and substitution for the cartilage of
a dense inanimate enamel, we imagine, are pro-
cesses which are not confined to the acetabu-
lum ; but their results are seen also on those
parts of the head of the femur which are sub-
jected to pressure and friction; hence we find
the effects of friction, above alluded to, most

cTun nerf et d'un vaisseau, ces parties fondament ales
de 1'organisation, semblent en quelque sorte re-
spectees par les lesions organiques, qu'elles soient
ces lesions circulent tout autour, mais ne les en-
vahissent presqtie jamais, on du moins les envahis-
sent apres tous les autres tissues lorsquelles so n't
parvenus a leur derniere periode.

* Dublin Journal for March 1839, No. xliii,
3 G

802

ABNORMAL CONDITIONS OF THE HIP-JOINT.

upon the upper surface of its head which
supports the acetabulum in standing and pro-
gression. The form of the head of the bone
becomes changed and flattened from above
downwards ; something like a bending or
yielding of the neck of the bone may now
be observed, and sometimes the inferior part of
the circumference of the head of the femur is so
much depressed that the under surface of the
head has approached to the lesser trochanter.

Fig. 317.

Upon a cursory examination, it looks as if the
" head of the bone were forced downwards by
the action of some great pressure from above,
and cases have occurred in which at last the
head of the femur seemed to have sunk even
below the level of the great trochanter, and to
be supported by the lesser." ( B. Bell.)

But besides these which we attribute to the
effects of physical causes, there is, in the con-
templation of the morbid results of this chronic
disease of the hip-joint, sufficient to satisfy us
that a very active vital process is going on in
the interior of the bones, as well as in all the
structures around the diseased joint. The
thickening of the fibrous capsule, and hyper-
amic state of the synovial structures, the exu-
berant growth of bone which we see around
deepening the acetabulum, or surrounding its
brim with bony nodules; the enlargement of
the head of the femur, so as to make this head
assume an oval convex surface, measuring in
circumference ten inches and a half, as in the
specimen from which the drawing (Jig. 317) was
taken, all these are sufficient proofs that besides
the interstitial absorption going on in the interior
of the cervix femoris in these cases, a very
active condition of the minute arteries exists
externally, giving birth to those exostotic
deposits which encircle the head and inter-
trochanteric lines of the femur. It has been
remarked, and we think with much truth, that
those specimens which have been frequently
produced and mistaken for united fracture of
the neck of the femur, have been examples of
interstitial absorption of the neck of this bone
combined with external exostotic deposits; but
these mistakes, however, we trust are not here-
after likely to occur.

SECTION III. Accident. — The hip-joint is,
of course, like the other articulations, liable to

sprains and to contusions. These do not re-
quire any special notice here; but fractures
and luxations of the bones of this important
articulation demand from us full consideration.

I. Fractures. — Fractures of the os innomi-
natum may traverse the bottom or fundus of
the acetabulum, or some portion of the brim
of this articular cavity may have been broken
off.

1. Fracture oj" the acetabulum . A. Fracture
of its fundus. — When fracture of the bones of
the pelvis happens to traverse the bottom of the
acetabulum, the prognosis is unfavourable, as it
is in all casesof fracture of the bones of the pelvis.
When this fracture through the fundus of the
acetabulum is the consequence of a fall on the
feet, knees, or trochanter major of the femur, it
sometimes happens that the head and neck of
the femur unbroken are driven into the
cavity of the pelvis. " Nous avons observe,"
says Dupuytren, " plusieurs ibis, 1'enfonce-
ment de la cavite cotyloide par la pression
exercee par la tete du femur, a la suite d'une
chute sur le pied ou les genoux." In this case,
the head of the femur is driven with force
against the fundus of the acetabulum, and the
hitter breaks, and is crushed in, " enfonce." The
most remarkable case observed by Dupuytren
was the following : — " The bottom of the cotyloid
cavity had been driven in, and the head of the
femur had passed entirely into the pelvis. The
neck, which had not suffered any solution of
continuity, was so strongly engaged in the
opening, that, even when making the anatomi-
cal examination, I found it very difficult to
disengage it, and to reduce this new species of
luxation."* As these important remarks of
Dupuytren are not accompanied by all the
detail that is to be desired, where novel obser-
vations are reported, we shall here adduce the
following case of fracture of the fundus of the
acetabulum, with displacement of the head of
the femur into the pelvis. Death occurred on
the fortieth day after the injury, from diffuse
inflammation. An opportunity was afforded to
us of investigating anatomically the precise na-
ture of the lesions in this case.

On the 3rd of December, 1834, a man,
named William Sherlock, set. 26, a painter by
trade, was admitted into Jervis-street Hospital,
under the care of the late Mr. Wallace. A
few minutes before his admission, this poor
man had fallen from a ladder, from a height
reported to be fifty feet, on the flags of the
street. On the next day, the 4th of December,
when he had recovered from the insensibility
and collapse which had succeeded to the fall,
we found him complaining of intense pain of
the right hip. He was quite unable to move
the right thigh, and would not permit any exa-
mination of the hip, as the slightest movement
communicated to the limb produced intense
agony. The integuments covering the tro-
chanter were discoloured, and there was much
swelling around the hip-joint. The right or
injured extremity was two inches shorter than
the left, which circumstance he attributed to a

* Lecons Orales.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

803

fracture of the femur, which had occurred some
years previously. Besides this severe injury of
the hip, it was also manifest, from some
dyspnoea, cough, and bloody expectoration, that
his chest was also injured, but venesection and
other suitable treatment having been resorted
to, the affection of the chest seemed to subside.
His cough and dyspnoea for a time had disap-
peared, and his pulse fell to 80. On the twenty-
third day from the accident, he said he felt that
he had caught a most severeand violent cold, from
a window having been kept open over his head.
On this (23rd) morning, I found him suffering
from great difficulty of breathing and violent
fits of coughing, accompanied by scanty frothy
expectoration. His pulse was 110, and hard,
his tongue was brown and dry, his skin was hot,
and I learned that these symptoms had suc-
ceeded to a rigor. They were attributed by me
to pneumonia with acute pleuritis and consi-
derable effusion, of which there were found, on
examination of the chest by auscultation and
percussion, very evident signs. These were
actively combated by the ordinary treatment,
but without success. His pulse was generally
120. He had cough, with muco-purulent ex-
pectoration, and dyspnoea. He slill obstinately
refused to permit any accurate examination of
the limb to be made. He said his right thigh
was now as powerless as at first, but the injury
did not prevent him sitting up in bed, when,
from the urgency of the dyspnoea, he felt the
desire for this position ; on one occasion he
had himself taken up, and placed for a time
sitting up in a chair. On the thirty-third day
after his admission, I found that his right leg and
thigh had swollen, that he had raved much
during the night; and that he had alternate
flushings and paleness of countenance, which
betrayed much distress. He now complained
of pain in the right shoulder. His pulse was
130, small and compressible. He had reten-
tion of urine. His temper was irritable; his
tongue was red, and morbidly clean and dry.
He had much thirst. His lips were pale and
bloodless. He died on the 12th January, the
fortieth day from the accident.

Post-mortem examination. — There was effu-
sion of pus into the cavity of the right pleura,
and the usual results of acute pleuritis ; pus
also in the cavity of the pericardium, and a thin
reticulated layer of lymph on the surface of the
heart. An incision made through the soft parts
to expose the bones of the hip-joint gave exit
to a large quantity of dark brown serum, mixed
with pus. This collection of matter extended
from the superior part of the thigh, under the
peritoneum up to the kidney. The soft parts
having been removed, and the bones exposed,
it was found that the shaft, head, and neck of
the femur were uninjured, but the head of ihe
bone was driven through the fundus of the
acetabulum, which was fractured in a stellated
manner, having been divided into three por-
tions. The spiculated edges of the cavity pro-
truded into the pelvis to the extent of one inch.
They were sharp and hard. Nature had not
made the slightest attempt at reparation. The
finger could be passed along the neck of the

thigh-bone into the cavity of the pelvis,
through the perforation in the bottom of the
acetabulum. The pelvis had been broken in
several places. There was a comminuted
fracture of the horizontal ramus of the pubis
near its crest. There was another fracture of
this ramus at its junction with the ilium, and
a fracture through the body of the os innomi-
natum extended from the anterior inferior spi-
nous process to the great sciatic notch.

B. Fracture of the brim of the acetabulum.
— The superior and back part of the cotyloid
cavity, which overhangs the head of the femur,
which is called by Soemmering the supercilium,
is sometimes broken off, and it follows almost
as a necessary consequence, that a dislocation
upwards and backwards of the head of the
femur shall occur. It is an accident most liable
to be mistaken, and most difficult to manage.
We believe, indeed, in all the cases which have
occurred, that permanent lameness has been the
result. In such cases, the luxation of the hip
is reduced without much difficulty, but dis-
placement again shortly recurs. In symptoms
and effects the case has a strong resemblance
to the congenital luxation of the femur. I was
once invited by my friend, Mr. Hilles, (now of
London,) to see a case of supposed dislocation
upwards and backwards on the dorsum of the
ilium. I met the late Dr. M'Dowel in con-
sultation on the case. It was as follows : —

Thomas Venables, aet. 25, on the 4th of Oc-
tober, 1834, received a severe injury of the
right hip-joint in leaping across a ditch, having
alighted with force upon the right leg. He fell
immediately, and was unable to rise from the
ground, or to walk or stand when raised.
When the patient was supported in the erect
posture, he had the ordinary symptoms of dis-
location of the thigh-bone upwards and back-
wards on the dorsum of the ilium. No cre-
pitus was discovered. On the following
morning an extending force having been ap-
plied by the pulleys, the head of the bone
resumed its natural situation, and the deformity
of the limb disappeared. When the patient
was visited on the following morning, (the 6th,)
it was found that during the night the head of
the bone had started from the acetabulum, and
that all the former signs of the injury had re-
appeared. On the 7th, the displacement was
again reduced. While the bone was yielding
to the force of the pulleys, the writer had the
palm of his hand pressing on the great tro-
chanter, as this last advanced slowly towards
the acetabulum. He was sensible of a rough
grating sensation, which was communicated to
his hand, and gave him the idea as if the head
of the bone were dragged along a scabrous rough
surface. The case proceeded favourably until
the night of the 10th, when, owing to the dis-
turbance occasioned by the action of a purga-
tive medicine, the dislocation recurred a third
time. It was observed that, although when the
patient was supported out of bed the foot was
inverted, still the toes could be somewhat
everted. An accurate examination being now
instituted to ascertain whether a fracture ex-
isted, a distinct crepitus was discovered at the
3o 2

804

ABNORMAL CONDITIONS OF THE HIP-JOINT.

upper and back part of the acetabulum. The
crepitus and frequent recurrence of the dis-
placement rendered it sufficiently obvious that
the brim of the acetabulum had been broken
in the above-mentioned situation. The bone
was a third time restored to its place, and a
strong band placed around the pelvis. In 1836,
I admitted the man into the Richmond Hos-
pital. He was at this time unable to walk
without the assistance of a crutch. The in-
jured limb was one inch and a half shorter than
the other. When standing, he rested it upon
the points of the toes, the heel being drawn
upwards ; but a slight degree of extension was
sufficient to restore it to its natural length ; and
when the man was lying in bed there was
hardly any difference perceptible in the length
of the two limbs. The breadth of the injured
hip was occasionally greater than that of the
sound one, and the head of the femur could be
pushed upwards easily, and, of course, it al-
ways ascended, when the patient endeavoured
to support his weight upon it; and in many
motions of the joint, the rubbing together of the
broken surfaces was distinctly audible.

After having remained in the Richmond
Hospital under our observation for two months,
he was discharged. Nothing could be devised
to make his limb more useful to him. The
fracture, therefore, of the supercilium of the ace-
tabulum is a very serious injury, which it be-
hoves surgeons to be well acquainted with. A
successful mode of managing such cases has
not yet been exemplified.*

2. Fracture of the superior extremity of the
femur. — The head of the femur is so protected
by the acetabulum, that it is seldom or never
fractured, except by gunshot injuries. The
neck and rest of its superior extremity are,
however, we find, subjected to various accidents.
The general symptoms of fractures of the neck
and upper extremity of the femur are, that the
affected limb is shorter than the other, the heel
rises to the ievel of the opposite malleolus, the
patella, leg, and foot seem much everted ; there
is a flattening of the natis, and a fulness of the
groin. The patient does not attempt to stand,
much less to walk. There is in the part itself,
as it were, a conscious inability to support the
weight of the body, and even when the patient
is lying on a horizontal plane, as in bed, we
,n'nd that he cannot, by the unassisted effort of
the muscles of the injured limb, elevate it from
the horizontal level, upon which it lies power-
less. When the surgeon, standing at the foot
of the bed, seizes the affected limb, and pulls
it towards him, so as gradually to overcome the
contractile power of the muscles, the limb is
restored to its natural length, and if now we
resort to the painful expedient of rotating the
thigh, crepitus is rendered manifest. When-
ever the surgeon relaxes the force by which the
limb was restored to its natural length, the
shortening, eversion, and deformity of the limb

* In the twelfth volume of the Dublin Medical
Journal, Mr. R. Smith has made some valuable
observations on this case, in relation to the diag-
nosis of obscure cases of injury of the hip and
--!i*mlder-jnints.

recur. Such are the general signs of fracture
of the upper extremity of the thigh-bone.
The portion of the bone, called the neck, may
be fractured transversely with respect to the
direction of its long axis, either within or with-
out the capsular ligament. The first is deno-
minated the intra-capsular fracture, the second
the extra-capsular fracture. Oblique fractures
of the neck of the bone are not impossible.

A. Intra-capsular fracture of the neck of
the femur. — This fracture has been seldom
seen in the young subject, but is one of the
most common accidents to which elderly peo-
ple are liable. In such persons many cir-
cumstances in their organization appear to ac-
count for their great liability to this accident.
Their muscles have lost their firmness, and are
more or less in a state of atrophy ; the trochan-
ter major becomes peculiarly prominent; the
neck of the femur yielding somewhat, perhaps,
to the weight of the body, descends and loses
some of its obliquity. This atrophy of the
muscles and bones is not so frequently noticed
in the male as in the elderly female, in whom
the breadth of the pelvis is greater and the tro-
chanter major more projecting. These obser-
vations account sufficiently for the great liability
to the intra-capsular fracture, which we notice
in the elderly subject, and for the more fre-
quent occurrence of the accident in the aged
female than in the male. In the young subject
the trochanter major does not project so much,
the muscles surrounding the hip-joint are re-
markably firm, and when falls on the side
occur, the surrounding muscles and the os in-
nominaturn share, with the great trochanter, the
weight of the fall. The bone in the young
subject is better calculated from its form and
its organization to resist the effects of falls on
the trochanter, and in these fractures of the
neck of the femur have been rarely witnessed.
In the young subject, too, the neck of the
femur is comparatively shorter than in the aged,
the angle of union of the neck with the shaft of
the bone is more open, and the axes of both
neck and shaft are more in a line. The great
proportion of animal matter existing in the
bones of the young, and consequent elasticity
of the bone, render it capable of resisting frac-
ture, while, on the contrary, the comparative
deficiency of animal matter, arid the consequent
redundancy of earthy material in the aged sub-
ject, render the neck of the femur friable. In
a word, the tissue of the bones in general does
not escape, in the aged, that atrophy which
affects the rest of the system, and when we re-
collect the functions which the neck of the
thigh-bone has to perform, we shall not be sur-
prised to learn that the effects of this atrophy
are more readily felt and seen in this part of
the osseous system than perhaps any other.
The superincumbent weight of the body and
the action of muscles must have a tendency to
diminish the obliquity of the neck of the thigh-
bone, to render it more horizontal, and conse-
quently less capable of bearing up against the
effects of concussion.

Besides the loss of obliquity of the neck of
the thigh-lwne, we find two othor c;irrumst;iu-

ABNORMAL CONDITIONS OF THE HIP-JOINT.

805

ces relative to the neck of the bone itself, ren-
dering it very liable to fracture in the aged. I
mean the expansion of the cells, by which the
strength of the interior of the bone is dimi-
nished ; and, secondly, by the partial removal
by absorption of that long bony arch of com-
pact tissue, upon which in the adult depends,
we believe, the principal strength of the neck
of the bone (jig. 318) ; and even in many aged
subjects, we rind the partitions of the bony
cells removed, and a large cavity filled with
fatty medulla occupies the centre of the cervix
femoris. All these alterations obviously weaken
this portion of the thigh-bone, and we feel very
little doubt but that when the condition of the
bone above alluded to exists, even without a
fall a fracture may occur. \Ve have noticed
specimens of senile degeneration of the neck of
the femur in museums, in which the neck of
the femur had been removed gradually by ab-
sorption, so .that the head of the bone had ap-
proximated to the trochanters. Such specimens,
where the history of the case was unknown,
have, we doubt not, been from time to time
adduced as evidences in favour of the possibi-
lity of bony consolidation of the intra-capsular
fracture. These observations on the effects of
senile degeneration of the neck of the thigh-
bone sufficiently account for the remarkable
frequency of the intra-capsular fracture of the
cervix femoris in the aged subject from the
most trivial causes. The fracture, under such
circumstances, should, in our minds, be looked
upon more as a stage of morbid alteration,
from which no amendment is to be expected,
than as an accidental lesion, which the efforts
of nature and the aid of surgery can be deemed
adequate to repair.

B. Estra-capsular fracture of the neck, and
fracture of the superior portion of the shaft
the femur. — Fracture of the neck of the femur
may occur in a part of the bone immedi-
ately external to the synovial sac and capsu-
lar ligament; it may pass obliquely through
the cervix femoris and trochanters, or it may
occur in the cellular and spongy portion of the
bone which is immediately external to these
processes. In all these cases the accident is
usually met with in young and vigorous indivi-
duals, and is often very severe. There is in
these cases much deformity, great eversion of
the limb, with considerable shortening and
swelling. The fracture having traversed the
bone external to the capsular ligament, there
is but little to resist the full force of muscular
action upon the lower fragment of the bone,
while the upper is forced downwards by the
weight of the body, so that, from both these
causes, much shortening is produced. The
muscles are in a state of spasm, and at first
resist the surgeon's efforts to bring down the
limb to its normal length. The muscles gra-
dually yield to gentle and continued extension,
and if now a movement of rotation be commu-
nicated to the broken femur, a crepitus can be
felt by the hand pressing on the great troch n-
ter, which on rotation of the femur is perceived
to move in a small circle. Kversion of the
whole limb, in cases of fracture of the upper
extremity of the femur, has been noticed as

one of its most prominent symptoms, and the
cause of it may be fairly attributed to the pre-
ponderating influence of the rotators outwards,
to which the lower fragment is abandoned
when fracture has occurred : the rotators out-
wards are the glutaeus maximus, the three ad-
ductors, the pectinalis, the psoas magnus, and
iliacus internus, together with the obturators,
pyriformis, and other muscles, inserted into the
posterior inter-trochanteric line. These mus-
cles are solely opposed by the rotators inwards,
which are few and comparatively weak. Not-
withstanding the violence of the injury in ge-
neral, and the deformity, the prognosis in these
cases is much more favourable than in the case
of the intra-capsular fracture, because in the
former a solid bony union of the fragments
may be reasonably hoped for.

In considering the symptoms of fracture of
the superior extremity of the shaft and of
the neck of the femur, whether the seat of
fracture be within or without the synovial cap-
sule, it should be recollected that extraordi-
nary cases may occur; thus there may be
fracture combined with inversion of the limb.
The cause of this inversion, in particular cases,
has been sought for, and Mr. Guthrie gives
ingenious anatomical reasons for this rare symp-
tom, depending upon the line of direction the
fracture may have taken ; if, for example, the
fracture may have taken such a course as to
detach from the shaft of the femur the neck,
and at the same time also the lesser trochanter,
to which is attached the great rotator outwards,
the psoas and iliacus, and if at the same time
the attachments of the gemini, obturators, and
pyriformis be destroyed, in this case Mr. Guthrie
supposes that there is an anatomical reason for
the rotation inwards, as the tensor vaginae femo-
ris and the anterior fibres of the glutaeus me-
dius remain unopposed. This explanation is
ingenious, but the cause of occasional inversion
of the limb in fracture, noticed by Petit, De-
sault, and all subsequent writers, has not yet, in
our mind, been sufficiently elucidated. The
phenomenon of inversion of the foot, in cases
of fracture of the upper extremity of the femur,
is extremely rare, but it has been noticed in
the intra-capsular fracture, (Stanley, Smith,)
in the extra-capsular fracture, (Guthrie,) and
we have ourselves seen it in all these cases.
The deviation inwards, says Dupuytren, is so
rare, that we can scarcely reckon upon meeting
it once in a hundred cases. The surgeon of the
Hotel Dieu attributes much of the rotation out-
wards in fractures of the neck of the thigh-bone
to the action of the adductor muscles, but adds,
" il faut dire aussi, qu'on notice presqueaucune
partie d'une autre cause, qui cependant pent
seule rendre compte de la deviation en dedans,
et apprendre a y remedier. Je veux parler de
I'obliquite des fragmens dans la fracture du col
du femur, si le fragment interne se porte en
arriere, et 1'externe en avant, il y a alors devia-
tion en dehors. Si, au contraire, la fracture est
oblique, en sens inverse, la deviation aura lieu
en dedans. C'est done par I'obliquite des frag-
mens, que ces varietes de deviation peuvent
ctre apprecices."

(J . Fracture of the neck oj 'the fanur, cvwpli-

806

ABNORMAL CONDITIONS OF THE HIP-JOINT.

cated with fracture through the trochanter
major. — In the thirteenth volume of the Medico-
Chirurgical Transactions, Mr. Stanley has re-
marked that among the more complicated inju-
ries to which the hip-joint is liable, that of
fracture of the trochanter major, combined with
fracture of the neck of the femur, has, under
certain circumstances, a strong resemblance to
dislocation of this bone. Whenever the frac-
tured portions of the trochanter can be brought
into contact, a crepitus will be perceived, which
will enable the surgeon to ascertain the precise
nature of the injury ; but when from the direc-
tion of the fracture, one portion of the trochan-
ter major has been drawn by the muscles to-
wards the sciatic notch, no crepitus can then be
discovered. A direct source of mistake will
then arise from the positive resemblance of the
fractured portion of the trochanter to the head
of the femur, the former occupying the place
which the latter would do in dislocation, and
if, with these circumstances, there should hap-
pen to be inversion of the injured limb, the
difficulty of diagnosis must be considerably in-
creased. The writer has seen such cases as
those alluded to by Mr. Stanley, and when he
confined his observations to the consideration
of the joint only, he felt all the difficulty alluded
to in forming an opinion ; but in these cases
the limb can in general be brought down to its
natural length by forcible extension, and it is
possible, too, to flex the thigh on the abdomen,
which we know to be impracticable in the case
of luxation. In most of the cases which the
writer has witnessed of the fracture traversing
obliquely the superior extremity of the shaft of
the femur, detaching the trochanters, the foot
and whole of the injured extremity were everted,
a position it were impossible for the limb to
assume, were the globular-shaped head of the
bone on the dorsum of the ilium, or placed to-
wards the ischiatic notch, and indeed, in the
cases which he has seen, with inversion of the
limb, the inverted position was not permanent,
as when the patient was raised out of bed, and
assisted to stand for a few minutes on the
sound extremity, the injured limb gradually
assumed an inclination forwards and outwards;
the inclination, though slight, was always to a
degree which it were impossible to give to the
limb if the head of the bone were placed on
the sciatic notch. Finally, as to the remark-
able symptom of inversion of the limb, com-
bined with fracture, we have never seen this in-
version so rigid as it is in the luxation ; the in-
version can be overcome, and we have mostly
found that in the cases in which this symptom
was noticed, there existed a comminuted frac-
ture of the superior extremity of the shaft of
the femur, and the limb, if left to itself, would
be found sometimes to be everted, sometimes
to be inverted, and generally to possess a re-
markable degree of flexibility, yielding to any
movements the surgeon wishes to communicate
to it. Such has been the result of the writer's
individual observations on these cases.

D. Fractures of the neck of the thigh-bone,
with impact ion of the superior or cotyloid frag-
ment into the cancellated tissue of the upper extre-
mity of the sliaft of the femur. — We have spoken

of a fracture of the neck of the thigh-bone, in
which the fracture runs transversely with respect
to the direction of the axis of the neck of the
bone, and also of oblique fractures of the cervix
femoris (Dupuytren). In the former, i. e. the
transverse fracture of the neck, the two opposite
surfaces of the fragments are generally fairly
confronted to each other, and each presents a
granular broken surface ; but instances have
been met with in which there existed an inter-
locking of these surfaces. A bony spicula or
dentiform process, as it were, has been seen to
proceed from the broken surface of the superior
or cotyloid fragment, and to sink into an alveo-
lar-like depression on the upper surface of the
lower fragment ; to use the words of Cruveil-
hier : " L'engrenement des fragmens s'observe
moins souvent, peut-ctre dans la fracture intra-
capsulaire que dans la fracture extra-capsulaire.
Cependant je 1'ai observee plusieurs fois ;
dans un cas de fracture intra-capsulaire du col,
observe sur un adulte tres vigoreux, j'ai trouve
un engrenement reciproque forme ainsi qu'il
suite le fragment superieur et le fragment infe-
rieur presentaient chacun une cavite, et une
avance osseuse ; la cavite de 1'un recevait
1'avance de 1'autre et reciproquement, 1'engrene-
ment etait, qu'il y avail immobilite complete."
In the species of fracture which we are now
about to consider, the superior or cotyloid frag-
ment is firmly impacted into the cancellated
structure of the superior part of the shaft of the
femur. In this case the limb is shortened
somewhat, though not much, and consequently
the case may be mistaken for the intra-capsular
fracture. When, however, the surgeon endea-
vours to bring the limb to its normal length,
and to elicit crepitus, or by rotation of the
femur he endeavours to ascertain whether the
trochanter moves in a larger or smaller circle,
he finds that he cannot elongate the shortened
limb, nor elicit crepitus by rotation, nor can he
learn anything* satisfactory by the movement of
the trochanter. In general the fracture is com-
plete of the compact and reticular tissue of the
neck of the bone, and the upper fragment is
wedged into the lower, as is the fang of a tooth
into its alveolus ; but cases, we believe, have
occurred, in which the fracture of the cervix
femoris was incomplete, and had engaged
merely the under stratum of the compact tissue
of the neck of the bone. To comprehend well
what occurs in the partial as well as in the im-
pacted fracture, we should attend a little to the
normal anatomy of the interior of the cervix femo-
ris, and the disposition of the compact and reti-
cular tissue, a subject the writer has elsewhere
stated has been much overlooked, see Dublin
Journal, vol.vi. p. 222, from which we quote the
following words : " Let us make a vertical sec-
tion through the neck of a healthy femur, in the
direction of its long axis, and continue it down
through the shaft of the dry bone, the section
leaving one-half of the femur in front, and the
other behind with the lesser trochanter, as has
been done in the specimen of the healthy femur
of a well-formed adult man, from which Jig. 318
has been taken. This simple view shews us, that
the principal strength of the neck resides in au
arch of compact tissue, which begins small

ABNORMAL CONDITIONS OF THE HIP-JOINT.

Fig. 318.

where the globular head joins the under part of
the neck, but which gradually enlarges down-
wards towards the lesser trochanter, and even
so low as the middle of the femur, where it
will be found nearly twice the breadth of the
opposite wall of the shaft of the bone ; the
compact stratum which, scarcely thicker than a
wafer, invests the entire of the head, upper part
of the neck, and trochanter, seems to have little
reference to any design of imparting strength or
resistance to this portion of the bone, and the
same may be said of the whole of the reticular
tissue of these processes, while, on the contrary,
the compact tissue of the under surface of the
neck seems artfully arranged, if we can so say,
so as to give support to the weight of the body
in the erect position ; hence do we find this
compact stratum thrown into an arch, upon
which the weight of the body falls, as that of a
carnage does on the C spring which sustains it.

When we fall or leap from a height on the
feet or knees, the thin upper stratum of the
neck, and the whole of the reticular tissue of
the bone will first receive, and probably yield
somewhat to, the weight, by which some of the
force of the shock may be decomposed, but to
the bony arch of compact tissue, to which we
have alluded, must ultimately be referred any
violence which the neck of the femur can re-
ceive from any impulse transmitted from above.

We seldom hear of a fracture of the neck of
the femur occurring to a healthy adult when he
falls with violence on his feet or knees, for the
weight of the superincumbent body is thrown
in the most favourable manner on the bony
arch of compact tissue before alluded to, which
from its density and form, and strength deriva-
ble from both, it is almost always able to
resist ; and even a fracture of the acetabulum

807

or rupture of the capsular ligament and dislo-
cation are accidents more likely to happen
under these circumstances.

But, on the other hand, let us suppose a
person to fall on the trochanter major, which is
resisted by the ground, while the weight of the
pelvis, &c. acting oblique!) on the under sur-
face of the neck, will have a tendency to bring
the neck of the femur into a straight line with
the shaft of the bone, or in other words, to
efface its obliquity ; here the compact tissue, so
often alluded to, receives the force from below
in a most unfavourable manner, and this tissue
cracks across, and if no more happens for the
present, we shall have the simplest form of
partial fracture of the neck of the femur.

While circumstances are in this state, we
can conceive the possibility of a patient being
able to stand after such an accident, and even
walk for some distance; and when examined
by the surgeon, we can understand how the
latter, as it has often happened, might be de-
ceived into the opinion that there was really no
fracture. Again, we can easily imagine how
under such circumstances an awkward move-
ment or a fall may render the fracture complete,
or how, from a severe secondary injury, or even
the continued action of the first impulse, some-
what varied in its direction, the upper fragment
of the broken neck of the femur could be
wedged into the cancelli of the shaft.

Anatomical characters of fracture of the
neck of the thigh-bone. — In those cases in which
opportunities have occurred of making recent
anatomical examinations of those who have
died shortly after having suffered fracture of
the neck of the thigh-bone, blood has been
found extensively extravasated beneath the skin,
among the interstices of the muscles, and we
find the line of the fractures through the tro-
chanters and upper portion of the shaft of the
femur itself marked out by blood in a coagu-
lated state, which had insinuated itself into and
among the interstices of the broken bones.
When we examine a case of intra-capsular
fracture which had taken place a long time
previously to the death of the patient, very
remarkable changes in the structures around
the joint are noticed. The muscles, when com-
pared with those of the opposite side, are more
or less atrophied. This observation, however,
only applies to the greater number of the
muscles around the hip-joint, as some of the
smaller ones (in cases of ununited fractures of
the neck of the thigh-bone of long standing)
are usually found to have undergone a con-
siderable change in their appearance and struc-
ture; of all these, the obturator externus seems
to be the most changed and thickened. This
is easily accounted for, when we recollect that
when the neck of the femur is fractured, there is
a strong tendency in the muscles around the joint
to drag up the femur, and cause its shortening ;
indeed, the capsular ligament and the obturator
externus alone resist the ascent of the head of
the bone on the pelvis. The tonic force of the
muscles has constantly this tendency to elevate
the femur on the dorsum of the ilium, and
when the patient begins to walk, and to throw

803

ABNORMAL CONDITIONS OF THE HIP-JOINT.

his weight on the fractured limb, then it is
more particularly that the power of the obtu-
rator externus is called into action to restrain
the ascent of the trocbanter major, which is
kept downwards by the obturator and by the
strength of the capsular ligament, which under-
goes a corresponding change of structure. The
capsular ligament has been found semi-cartila-
ginous, and occasionally even spiculae of bone
have been found in it ; we have also known it
to be much elongated, so as to allow the lower
fiagment to ascend much on the dorsum of the
ilium. We have found the capsular ligament
usually entire in old cases, but occasionally the
bursa, which exists in front of or under the
psoas muscle, seems to have freely communi-
cated with the interior of the joint. In some
cases the natural thickness of the capsule is
not much increased ; in others it is very con-
siderably so. In one of the cases alluded to
by Mr. Colles, the capsular ligament was a
quarter of an inch thick, in some places half an
inch, and it had, at the same time, a firmness
of texture which might be termed semicartila-
ginous. Two or three particles of bone were
found in it. The synovial membrane, where it
meets the neck of the femur, has been fre-
quently found lacerated in -recent cases; in
older, inflamed, and in older still, adhesions of
the synovial structures to each other have been
observed. Thus the head of the fractured
femur has been found adherent to the acetabu-
lum, and we have frequently found filamentous
adhesions between the synovial membrane of
the neck of the bone and the interior of the
synovial lining of the fibrous capsule. The
synovial membrane, in the normal state, where
it invests the narrowest part of the neck of the
bone, is thrown into longitudinal plicae or folds;
some of the lowest and most distinct of these
are denominated by \Veitbrecht " retinacula."
We do not believe that this accurate anatomist
gave this name to these nbro-synovial folds
with any practical knowledge of the functions
which they occasionally perform in cases of
fracture ; but we know very well by experience
that, in recent cases of the simple intra-capsular
fracture of the neck of the femur, it very fre-
quently, if not generally, happens that, although
the neck of the femur is 'broken transversely
with respect to its longitudinal axis, the cylin-
der of fibro-synovial membrane, which is re-
flected over the neck of the bone, is sometimes
left unbroken, or is only partially lacerated.
The fibrous periosteum, which is here added to
the synovial investment of the neck of the
femur, strengthens much this part of the mem-
brane, and both together, in cases of intra-cap-
sular fractures, serve the purpose of keeping
nearly in apposition the broken fragments; and
in cases in which the greater part of this cylin-
drical investment of the neck of the bone re-
mains entire, or nearly so, the unbroken mem-
brane and the vessels which pass along it must
be the medium of vascular communication be-
tween the fragments.

The phenomena which extra-capsular fractures
present are not unlike those which are the result
of fractures elsewhere of the femur. We may

remark, however, that one of the results of this
lesion of the neck of the femur (as it is, in-
deed, of almost all other injuries or alterations
of structure of this part of the bone) is, that
the posterior part of the neck of the femur is
diminished one-half in its normal length ; the
posterior inter-trochanteric ridge of bone ap-
proaches to within half an inch of the circular
line which marks the junction of the head and
neck of the bone. A large quantity of callus
is usually thrown out in the line of the extra-
capsular fracture, and the trochanter major be-
comes much deformed by it, and the neck so
much shortened, that there is danger of the
motions of the hip-joint being interfered with.

In recent cases in which intra-capsular fracture
had occurred, little or no change has been ob-
served worth noticing ; but in old cases several
phenomena of importance present themselves.
1st, In some cases we find a false articulation
to have been formed ; 2dly, there is union of
the broken surfaces of the upper and lower
fragment by means of ligamentous bands;
3dly, it is reported that complete bony union
is effected, but the controversy upon this sub-
ject can scarcely be said to be yet terminated.

Very soon after intra-capsular fracture has
occurred, the surfaces of the broken frag-
ments undergo changes ; they are smoothed off
by the power of the absorbents, or are mechani-
cally rubbed down by the friction of the broken
surfaces, or by both these processes combined.
In general the neck of the femur disappears
altogether, and the basis of the head of the
bone corresponds to the level of the circular
brim of the acetabulum. The surfaces are ge-
nerally brought into contact by the muscles,
and frequently adhesions are formed between
the neck of the bone and the internal surface
of the capsular ligament, which, as has already
been remarked, is greatly thickened ; an oily
fluid, resembling natural synovia, is shed over
the broken surfaces, and here are all the ele-
ments of a false articulation present. The tro-
chanters are, in consequence of the removal of
the neck of the bone, brought near to the edge
of the acetabulum, and bony growths generally
shoot out from these processes and from the
inter-trochanteric line posteriorly. These bony
projections or vegetations sometimes rise as
high as the edge of the acetabulum, and when
the patient stands or walks, these bony growths
rising up from the trochanter are supposed to
afford a prop to the pelvis, and thus to assist
somewhat the structures which perform the
functions of the false articulation. It has been
noticed that, in general, the removal of bone
from the upper fragment extends as far as the
basis of the head and the level of the circular
brim of the acetabulum ; but in some cases this
fragment has been hollowed out. Again, in
obedience to influences which we cannot ex-
plain, it has happened that the lower surface of
the upper fragment formed an uniform convex
surface, looking downwards, and corresponded
to a large excavation formed in the substance
of the great trochanter. This, we find, occurred
in one of Mr. Colles's cases : the lower surface
of the upper fragment was convex, and covered

ABNORMAL CONDITIONS OF THE HIP-JOINT.

809

with spots resembling ivory, while the upper
surface of the lower fragment was widely ex-
panded into a cup. \Ve have, in our museum,
a very remarkable specimen of this abnormal
condition of the hip-joint. The upper orcoty-
loid fragment seems united to the acetabulurn
by an imperfect anchylosis, while the lower
surface of this fragment represents perfectly the
half of a sphere looking downwards ; the neck
of the femur has been entirely removed, and a
cup is hollowed out in the great trochanter to
receive the convex surface of the upper frag-
ment above alluded to. This surface, as well
as the cavity formed in the trochanter, have the
polish and hardness of ivory. The history of
the case, as to how the functions of the joint
had been performed, is unknown. The patient
died in the Richmond Hospital, under the care
of Dr. Hutton, of a disease unconnected with
the chronic affection of the hip-joint. In the
examination of old cases of intra-capsular frac-
ture, we have found the capsular ligament short
and strong, as already mentioned, and that it
retained the trochanters close to the brim of the
acetabulum, the cervix femoris having been
altogether removed. In a case which Mr. Bra-
bazon and the writer examined lately, of an old
woman who had fractured the neck of her
femur several years before her death, and in
whom there was shortening of the extremity for
two inches and a half, the neck of the femur
had altogether disappeared to its base The
surface on the internal part of the shaft of the
femur, from which the neck of the bone nomi-
nally springs, was plane and smooth, and no
vestige even of the lesser trochanter existed.
The under surface of the globular-shaped head
of the femur was removed to the exact level of
the brim of the acetabulum, in which the re-
mainder of the head was still retained by an
inter-articular ligament, which seemed to have
been reduced to the structure of loose cellular
membrane. The acetabulum of this side, too,
was evidently smaller than that of the opposite
side, and the cartilage covering it, and that also
investing the remnant of the head of the bone,
were partially removed. From want of use, it
would appear that all these parts were in a
state of atrophy. In this respect there was a
correspondence between the internal and exter-
nal structures of the broken limb, for the whole
extremity was deformed, shortened, and, as is
usual, much reduced in size when compared
with the opposite limb. Union by means of
a ligamento-cartilaginous substance is by no
means uncommon. In this case, as in almost
all others, the neck of the thigh-bone altogether
disappears, and the trochanters are brought up
to the level of the acetabulum, which still re-
tains the remnant of the head of the bone. The
broken surfaces are united closely enough to
each other by a fibrous substance, and this
union is sufficiently analogous to that which
we frequently see in cases of fractured olecra-
non or patella.

We have spoken of a species of fracture
which is called the impacted fracture. In this
case the femur is broken generally at the basis
of the neck, not far from the inter-trochanteric

lines : sometimes it is only the under part of
the neck which is broken, and then the frac-
ture is only partial ; but generally the compact
tissue all round this portion of the neck is, by
an accident, cracked across, and the superior
fragment, that is, the whole of the cervix femoris,
is impacted into the cellular structure of the
superior extremity of the shaft of the femur
(Jigs. 319, 320). The limb is shortened half an
inch, and in general everted. In the Dublin
Hospital Reports, vol. ii. Mr. Colles has given
a good delineation of this species of fracture.
In Sir A. Cooper's work, also, similar specimens
may be seen of this impaction of the upper frag-
ment. " La realite de ce fait iuteressant" seemed
new to the editors of Dupuytren's " Lecons
Orales," in 1832, in which we find it stated that
the superior fragment of the broken neck of the
thigh-bone is sometimes driven into the thick-
ness of the spongy texture of the superior ex-
tremity of the inferior fragment, and the conso-
lidation is effected readily enough. To con-
clude in the words of the Lecons Orales :
" plusieurs pieces d'anatomie pathologique,
tirees du Museum de FHotel Dieu, et represen-
tant les fragmens ainsi consolides, ont etc mon-
trees a I'amphitheatre, et ont convaincu chacun
de la realite de ce fait interessant. II est utile
de noter cette cause de deviation; elle peut
rendre compte, suivant les cas, de quelques faits
exceptionnels de deviation du pied en dedans
dans la fracture du col du femur, faits excep-
tionnels, qui ont ete observes par plusieurs
auteurs."* In the museum of the Richmond
Hospital we have some specimens of this frac-
ture. Fig. 319 represents a section of the supe-

Fig. 319.

rior extremity of the femur of a woman who
met with this species of fracture. The history
of her case, as recorded in the catalogue, is as
follows : — " Mary M'Manus, set. 52. Fracture
of the neck of the femur external to the cap-
sule. The upper fragment has been driven
down, and has become firmly impacted in the
cancelli of the shaft of the bone. The trochan-

* Le?ons Orales, torn. ii. p, 100.

810

ABNORMAL CONDITIONS OF THE HIP-JOINT.

ter minor is split, the fissure passing at right
angles with the body of the femur. The de-
scending ramus of the pubis was broken ob-
liquely, the fracture passing downwards and
inwards from the thyroid foramen. There was
a large effusion of blood into the crushed can-
celli of the bone. The patient, from whom the
preparation 'was taken, was thrown down by a
cart loaded with hay. The horse and cart
passed over her. The injured limb was short-
ened three quarters of an inch, the foot was
everted, and the slightest motion was painful.
She died on the fourth day after the occurrence
of the accident, having never recovered from
the shock." Another specimen (fig. 320) shews

Fig. 320.

this species of fracture in the case of a woman
who survived the accident. " Alicia Sherlock,
set. 64. Section of the head and neck of the
femur, shewing fracture of the cervix external
to the capsule. The neck of the bone has sunk
nearly to a right angle with the shaft. The
compact structure which lines the concavity of
the cervix has been broken, while the very
thin stratum which invests the upper surface
has yielded to the force without breaking, but
the cervix has sunk into the cancellated texture
of the shaft at a right angle, and is now sup-
ported upon the lesser trochanter. There is no
motion whatever between the broken surfaces,
nor the slightest trace of fracture at the central
part of the neck of the bone. The injury was
produced by a fall on the trochanter. There
was but little alteration in the position of the
foot, but the tendency was to eversion. The
shortening amounted to half an inch, and cre-
pitus was not distinguishable. The patient
lived three months and a half after the receipt
of the injury." In both these cases we have a
confirmation of our opinion, that the reduction
of the compact arch of bone which occupies
the under surface of the neck of the femur to a
thin lamina, predisposes to fracture of this por-
tion of the neck of the thigh-bone. In the case
in which the examination was made four davs
after the accident (fig. 319) we find, of course,

that there was no osseous deposition around
the inter-trochanteric lines, but that, on the
contrary, in the case, A. Sherlock, (fig. 320),
which survived the accident for more than three
months, exuberant growths of bone surrounded
the seat of fracture, and contributed to form a
kind of socket, which received the superior
fragment, by means of which the patient was
enabled to throw her weight on the injured
limb, and even to walk. The lesser trochanter,
in most of the cases which we have examined,
was greatly increased by bony depositions, and
became a prop to support the head, and it is
probable that, in these cases, the acetabulum is
propped up by the growths of bone from the
shaft of the femur. " This is a mode of union,"
says Mr. Colles, (alluding to the impaction,)
u very little inferior to callus in point of firm-
ness, but very different in its nature," and
which, he conceives, is peculiar to fracture of
the neck of the thigh-bone. In these cases
Mr. Colles has found a thin cartilaginous plate
every where interposed between the neck and
shaft. The new osseous production could have
very little assisted in keeping the fractured
pieces in apposition, for it was principally
thrown out about the trochanters, a small por-
tion only being formed below the neck, yet the
motion allowed between the fragments was so
very inconsiderable, that it required a close in-
spection to discern it, so that, in this instance,
the new osseous matter contributed very little
to the consolidation of the broken bone, the
firmness of which (inferior only to bony anchy-
losis) must therefore be ascribed entirely to the
interposed thin plate of cartilage. In one of
Mr. Colles's cases, No. XI. a vertical section
shewed that the neck had been fractured near
to the trochanters, and lay across the top of the
shaft ; its broken extremity being in contact
with the outer plate of the shaft. The external
solid walls of the neck were very thin.* In a
specimen of fracture of the cervix femoris,
which we possess in our museum, the neck of
the bone has been broken at its basis, near the
inter-trochanteric lines, and was impacted nearly
transversely into the cancellated structure of the
shaft of the femur, and the force of the fall was
so considerable that the upper fragment has
absolutely penetrated the outer wall of the tro-
chanter, and would have been in naked con-
tact with the tendon of the glutaeus maximus,
had it not been for the existence of the bursa.
there situated.

From the specimens that we have examined,
and have in our possession, we entertain no
doubt but that solid bony union may take
place between the impacted cervix femoris and
the superior extremity of the shaft of the femur.
In all cases of the impacted fracture, when the
patient had survived the accident for a month
or more, whether the union was complete or
incomplete, exuberant growth of bone had
sprung from the inter-trochanteric lines.

Does bony consolidation of the intra-capsular
fracture of the cervix femoris ever occur ? —
This question has for the last twenty years been

* Dublin Hospital Reports, vol. ii. p. 351.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

811

much agitated; Desault, Platna, and John Bell
long ago expressed their opinion that a fracture
within the capsular ligament would not admit
of union by callus. Sir A. Cooper HI his
Treatise on Dislocations and Fractures (p. 127)
says, " In all the examinations which I have
made of transverse fractures of the cervix femo-
ris entirely within the capsular ligament, I have
never met one in which a bony union had taken
place, or which did not admit of motion of
one bone upon the other. To deny its possibi-
lity and to maintain that no exception to the
general rule can take place would be presump-
tuous, especially when we consider the varieties
of direction in which a fracture may occur, and
the degree of violence by which it may have
been produced; as, for example, when the
fracture is through the head of the bone and
there is no separation of the fractured ends, or
when the bone is broken without its periosteum,
and the reflected ligament which covers its
neck torn, or when it is broken obliquely,
partly within and partly externally to the cap-
sular ligament; but all I wish to be understood
to say is, that if it ever does happen, it is an
extremely rare occurrence, and that I have not
met a single example of it."

Sir A. Cooper's opinions, when they were
published, particularly in Paris, excited as-
tonishment, and many observations were made
in the clinical lectures and works of the day
upon the supposed error of the doctrine, that
the intra-capsular fracture of the neck of the
thigh-bone was not susceptible of bony consoli-
dation. Messrs. Roux, Dupuytren, and others
contended that they had treated many cases of
the intra-capsular fracture of the neck of the
thigh-bone successfully, and that bony consoli-
dation had been effected, and besides shewed
to their classes what they considered as decided
examples of such union of this fracture. They
did not content themselves by referring to living
cases, because these were likely to be ques-
tioned, but they produced various specimens
obtained by post-mortem examinations of per-
sons who had recovered from the effects of the
fracture, but had died of other disease. Some
of these specimens were examined by Mr.
Crosse, and some were sent to London to Sir
A. Cooper, but they failed to convince either
Mr. Crosse or Sir Astley that they were true
instances of the intra-capsular fracture consoli-
dated by bone. \Ve may say the same of some
pieparations in the museum of the Royal Col-
lege of Surgeons, London, which were supposed
to be proofs of a bony union of the neck
of the thigh-bone subsequent to a fracture
within the capsular ligament, but says Mr.
\Vilson, " I have attentively examined these
two preparations, and cannot perceive one
decisive proof in either of the bone having
been actually fractured." One of these cases
was published in the Edinburgh Medical and
Surgical Journal as an example of united
fracture. The writer has known many speci-
mens adduced as proofs of bony consolidation
of the intra-capsular fracture of the neck of the
thigh-bone, which, upon examination, were
found to have been the result of disease. The

neck of the thigh-bone, we know, is greatly
shortened when the hip-joint is the seat of that
abnormal change which we have stated to be
the result of chronic rheumatic arthritis, but
in this case the previous symptoms, the history
of the case, and when these cannot be collected,
the state of the acetabulum and other appear-
ances, sufficiently point out the difference.
Again, the effect of senile degeneration -of the
cervix femoris is very liable to be mistaken for
an united intra-capsular fracture. In this,
however, the history of the case, the co-existence
of the same condition on both sides, the pene-
tration of the interior of the attenuated cellular
structure by an oily medulla, and other charac-
ters of the senile degeneration, will serve to
prevent false conclusions. Lastly, we have also
frequently known specimens of the impacted frac-
ture, where the whole cervix has been firmly
driven into the substance of the great trochanter,
mistaken for examples of bony union of the in-
tra-capsular fracture. The quantity of callus that
is in these cases added to the great and lesser
trochanters, which encloses the impacted neck
of the bone, is calculated on a superficial exami-
nation to induce erroneous conclusions, but a
section of the bone, as represented in Jig. 320,
will explain the true nature of the case.

Various cases have been laid before the pub-
lic and read before different learned societies,
which have been considered as very decided
evidences of bony consolidation of the intra-
capsular fracture of the neck of the femur.

Case 1. — In the year 1827 Mr. Langstaff
presented to the Medico-Chirurgical Society of
London a specimen of what he considered to
have been an intra-capsular fracture united by
bone. The case was that of a woman who was
50 years of age when the fracture occurred.
She was confined for nearly twelve months to
bed after the injury, and during the remainder
of her life, that is, for ten years, she walked on
crutches. On dissection it was found that the
principal part of the neck of the femur was
absorbed, and the head and remaining portion
of the neck were united principally by bone,
and partly by a cartilaginous substance. The
capsular ligament was immensely thickened
and embraced the joint very closely, the carti-
laginous covering of the head of the bone and
acetabulum had suffered partial absorption, the
internal surface of the capsular ligament was
coated with lymph. On making a section of
the bone, it was evident that there had been a
fracture of the neck within the capsular liga-
ment, and that union had taken place by osseous
and cartilaginous media. With a view of ascer-
taining whether there was real osseous union the
bone was boiled many hours, which discoloured
it, but by destroying all the animal matter it
satisfactorily proved the extent and firmness of
the osseous connexion, and the vacant spaces
occupied with cartilaginous matter. These
appearances are represented by a drawing made
shortly after boiling.*

Case 2. — Dr Brulalour, surgeon to the hos-
pital at Bourdeaux, sent to London the parti-

* Vol. xiii. of the Society's Transactions.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

812

culars of a case of fracture of the neck of the
femur, which were read before the Medico-
Chirurgical Society on the 5th of June, 1827.
The following is an abstract of it. Dr. James,
an English physician, aet. 47, in good health,
was thrown from his horse on the 20th of March,
1826. He fell directly on the great trochanter,
but got up and walked a step or two, which
occasioned such acute pain in the hip-joint that
he instantly fell again. On examination im-
mediately after the accident, Dr. Brulalour
observed the principal signs of fracture of the
neck of the femur. Extension of the limb was
kept up for two months so as to preserve it of
its natural length. He recovered the full use
of the limb so as to be able to walk without
any assistance, even that of a cane. Dr. James,
on the 20th of December, about nine months
after the accident, was attacked with haernate-
mesis, which in two days terminated fatally.
The post-mortem examination of the right coxo-
femoral articulation shewed — 1st, the capsule
a little thickened; 2d, the cotyloid cavity
sound; 3d, the inter-articular ligament in a
natural state; 4th, the neck of the femur
shortened, from the bottom of the head to the
top of the great trochanter was only four lines,
and from the same point to the top of the small
trochanter six lines ; 5th, an unequal line sur-
rounded the neck, denoting the direction of
the fracture; 6th, at the bottom of the head of
the femur and at the external and posterior part
considerable bony deposit had taken place. A
section of the bone was made in a line drawn
from the centre of the head of the femur to the
bottom of the great trochanter so as perfectly
to expose the callus. The line of union indi-
cated by the callus was smooth and polished
as ivory. The line of callus denoted also that
the bottom of the head of the femur had been
broken at its superior and posterior part.

Case 3. — Mr. Stanley, surgeon to St. Bar-
tholomew's Hospital, in May 1833 read before
the Medico-Chirurgical Society of London a
case of bony union of a fracture of the neck of
the thigh-bone within the capsule, occurring in
a young subject set. 18. In the examination of
the body of this young man, who died of what
was considered to be small-pox about three
months after the accident of the hip-joint, no
other morbid appearances were discovered
besides those of the injured hip-joint. The
capsule of the joint was entire but a little
thickened, the ligamentum teres was uninjured,
a line of fracture extended obliquely through
the neck of the femur, and entirely within the
capsule, the neck of the bone was shortened,
and its head, in consequence, approximated to
the trochanter major. The fractured surfaces
were in the closest apposition and firmly united,
nearly in their whole extent, by bone. There
was an irregular deposition of bone upon the
neck of the femur, beneath its synovial and
periosteal covering along the line of the fracture.
Mr. Stanley adds, " the foregoing case is re-
markable from the occurrence of a fracture of
the neck of the femur within the capsule at an
early age, and it is, I believe, the only example
of it on record."

Sir A. Cooper has published a letter in the
Medical Gazette, April 1834, vol. xiv., which
is intended to explain his sentiments upon this
subject, and to set the profession in general
and the French surgeons in particular right as
to the conceptions formed of the doctrine he
held as to the susceptibility of the bony con-
solidation of the intra-capsular fracture. In it
we find the following case.

Case 4. — Mrs. Powell, aged above 80 years,
fell down in the afternoon of the 14th of No-
vember, 1824. Sir Astley Cooper saw her soon
after, and found her complaining very much of
pain in the left hip. The limb could be moved
in every direction, but this motion produced
excessive pain. She lay on her back with the
limb extended, and nothing whatever was done,
except to apply fomentations, in the first few days.
He believed there was a fracture of the neck of
the thigh-bone although the limb remained
quite as long as the other, and he could per-
ceive neither a crepitus nor any altered appear-
ance in its position, except a slight inclination
of the toes outwards. She had more constitu-
tional irritation than Sir Astley ever observed
from a similar accident. She suffered much
pain in the hip, and was in consequence obliged
to take an opiate, but she got very little rest.
She generally had much thirst. There was the
utmost difficulty in keeping her bowels open,
and she had great pain and difficulty in making
water. She had no appetite for common food,
and for three weeks appeared so weak that she
was under the necessity of taking wine and
brandy. For some time all her urine and
stools were passed in bed, but not involuntarily,
and only because she could not be persuaded
to use proper means; in consequence her back
became very sore. Latterly she complained of
pain in the abdomen, which was very tender
on pressure, and even the weight of the bed-
clothes was inconvenient. Her tongue became
very dry and brown, and the last twenty-four
hours she was insensible. She died on the
morning of the 19th December about five.

Examination. — This took place at seven in
the evening. There was some ecchymosis
amongst the muscles about the injured part
and in the cellular membrane about the sciatic
and anterior crural nerves. The greatest part
of the fracture of the neck of the thigh-bone,
which was entirely within the capsular ligament,
was firmly united. A section was made through
the fractured part, and a faint white line was
perceived in one portion of the union, but the
rest appeared to be entirely bone. This case, says
Mr. Swan, beautifully shews the principle which
Sir A. Cooper has advocated, viz. that when the
reflected ligament remains whole, and the bones
are not drawn asunder, the nourishment to the
head of the bone continues, and union will be
produced even in the short space of five weeks,
by only placing the knee over a pillow, and in
other respects leaving the case to nature.

We find Mr. Samuel Cooper is of opinion
that a bony consolidation of the intra-capsular
fracture is proved. He says,* " Sir A. Cooper

* Surgical Diet. p. 575, last cd.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

813

has satisfied himself that osseous union some-
times takes place, and he has in his own col-
lection a most unequivocal specimen of it,
which he was kind enough to show me two
years ago. The possibility of bony union is
now universally acknowledged, but the cure in
this way is far less frequent than that by means
of a ligamentary connexion."*

It does not appear to us that this question is
yet so entirely settled as the last writer's obser-
vations would lead us to imagine ; although in
this city (Dublin) the subject has been care-
fully investigated for many years, we do not
find our museums yet contain a single speci-
men of the intra-capsular fracture united by
bone. In Paris we find Cruveilhier, one of
the most eminent pathologists in France, ex-
pressing himself in the most unreserved manner,
that a bony consolidation of the intra-capsular
fracture was impossible. Not unaware, as must
be supposed, of the eight cases referred to by
his pupil, M. Chassaignac,f (amongst which are
those of Langstaff, Stanley, and Sir A. Cooper,)
Cruveilhier, to whom Chassaignac's memoir is
dedicated, thus expresses himself: — "Je suis
porte a considerer comme des cas de deforma-
tion de la tete et du col, la plupart, si non la
totalite des fails, que Ton invoque generalement
pour etablir la reunion de fractures intra-cap-
sulaires du col du femur, a 1'aide d'un cal os-
seux, le cal est impossible, parceque les frag-
menslibres, au milieu de la synovie,ne sont point
entoures des tissues charges de la reparation de
la solution de continuite." Thus not content
with asserting that bony union is impossible,
he further adds that he is convinced from nu-
merous pathological observations, and from ex-
periments on animals, that the ideas of bony
union by means of a first, a provisional callus,
and then by means of a final callus, are erro-
neous ; he is certain that there is but one and
the same callus, which passes through different
stages of development, until the ossification is
complete ; he is of opinion that the ends of the
broken bone, no matter how confronted or held
together, never are directly united. This union,
he thinks, can only take place through the in-
tervention of callus, which is always thrown
round the bones where fractured, like a clasp or
bony ferule ; therefore, he reasons, the cause of
the difference between the intra-capsular and
extra-capsular fracture, with reference to their
susceptibility of bony consolidation, is, that in
the first the fragments are as it were abandoned
to themselves to effect an union ; here there is
no bony ferule or clasp possible, while in the
second the fragments are in the same condition
as in all other fractures ; that is to say, they are
surrounded by soft parts, by the ossification of
which the bony clasp is formed. Thus does
he not only deny the possibility of bony conso-
lidation in the case of the intra-capsular fracture,
but endeavours to explain why the union is
impracticable.

We cannot agree with this eminent patholo-
gist in the observations that the ends of the

* Loc. cit.

t De la Fracture du col du femur. Par E. Chas-
saignac, M.D., Paris, 1835.

bones themselves take no part in effecting a
bony union, for in cases of impacted fracture
alluded to by us in a preceding article, particu-
larly in the case of Sherlock, from which
fig. 320 has been taken, bony consolidation had
taken place in almost the whole line of the
fracture, and could only have been effected
by the union of the two bony surfaces which
were confronted to each other. No doubt the
union here was further fortified by the external
effusion of new callus, which surrounded the
bone at the seat of the fracture. When we re-
flect on the cases adduced in proof of the bony
consolidation of the intra-capsular fracture, we
must either disbelieve the facts, or admit that
the union is not impossible.

It would have been satisfactory if the test by
boiling the specimens of the united fractures
had been resorted to in all these cases, as it had
been in Mr. LangstafFs ; this observation par-
ticularly applies to the case reported by Dr.
Brulalour. of Bourdeaux. We find in Chas-
saignac's report of this same case, taken from
the memoir sent to the Academy of Medicine
of Paris, (Seancedu 16 Avril, 1827) in alluding
to the specimen in question he says : — " Scie,
dans toute sa longueur le cal se presentait sous
la forme d'une ligne oblique, raboteuse, d'une
couleurmoins blanche etd'un consistence uu
peu moins ferme que le reste de 1'os."

We had thus far entered into this much agi-
tated question, when an interesting opportunity
occurred to us of making the post-mortem exa-
mination of a case of united intra-capsular
fracture. The history of the case was this : —

Owen Curran, set. 70, was for the last five
years an inmate of the pauper department of
the House of Industry ; he was very infirm on
his limbs, and his mind was in a state of
dotage; on the 1st of August, 1837, while
walking across his ward, he fell on his right
side ; he was unable to rise, and complained of
pain in his right hip; he was carried to bed,
and was immediately visited by the late Mr.
William Johnstone, who was then acting for
me as clinical pupil, who found the limb
everted, and only half an inch shorter than
the other. Mr. Johnstone considered the case
a fracture of the cervix femoris, which required
no other surgical treatment than that of placing
and preserving the limb in a semiflexed po-
sition over pillows. The old man suffered but
little pain in the injured part, at all events he
did not complain of it. In about five weeks
after the accident he was raised out of his bed,
and when placed standing, he was able to put
the heel of the injured limb to the ground. On
the 30th of September, that is, about eight
weeks after the accident, my friend Mr. Smith
entered in his note-book the following memo-
randum of this case : — " As the patient lies in
bed he can elevate the injured \irnb by the un-
assisted efforts of its own muscles. The ever-
sion is slight, and the degree of shortening
amounts to one inch ; no force can bring the
limb down to the length of the other. From
the history and symptoms, this seems to have
been a case of impacted fracture." This man
survived the accident one year and nearly

814

ABNORMAL CONDITIONS OF THE HIP-JOINT.

ten months, during which time he was con-
tented to remain most of the time in his bed,
but when placed on his feet, could stand very
well, and was able but unwilling to walk. On
Tuesday the 20th of May he got an attack of
bronchitis, which, the following Friday, ter-
minated fatally. At twelve o'clock, on Satur-
day, the 25th May, assisted by Mr. Brabazon
and some of the pupils of the hospital, I made
an examination of the body. The right leg and
thigh were much everted. The trochanter
major was elevated, and projected much out-
wards ; the degree of shortening just amounted
to one inch ; the muscles presented a healthy
appearance, the capsular ligament was of a yel-
lowish colour, and somewhat thickened. The
femur was removed from the acetabulum ; this
latter cavity presented a healthy appearance, ex-
cept towards the margin of it; here the cartilage
was softened. The round ligament was sound.
The head and neck of the bone had lost their
normal obliquity, and were directed nearly ho-
rizontally inwards (jig. 321); the cervix pre-
sented, both anteriorly and posteriorly, evidence
of a transverse intra-capsular fracture having oc-
curred ; the globular-shaped head was closely
approximated behind and below to the posterior
intertrochanteric line, and to the lesser trochan-
ter, so that the neck seemed altogether lost
except anteriorly, where a very well-marked
ridge of bone shewed the seat of the displace-
ment and of the union of the fragments.
Fig. 321.

Fig. 322.

This ridge is evidently the upper extremity of
the lower fragment of the cervix. The fracture
of the neck posteriorly was found to have been
closer to the corona of the head than anteriorly,
and the nbro-synovial fold in the former situa-
tion remained unbroken. A section has been
made of the bone through the head, neck, and
trochanter ; one portion has been subjected to
maceration and to boiling ; and the bony union
has been unaffected by these tests. Scarcely
any portion of the neck can be said to have
been left.

The section, fig. 322, shews the compact line
which denotes the union of the fragments ; the
head and shaft seem to be mutually impacted
into each other, and almost the whole of the
cervix has been absorbed ; the line of union is
serrated, solid, and immoveable; and the cells of
the head and substance of the shaft seem to
communicate freely in all places, except where
the thin line of compact tissue here and there
points out the seat of the welding together of
the remaining portions of the head and neck of
the femur.

The bone was in its recent state, on the 25th
of May, laid before a meeting of the Patho-
logical Society. It seemed to be the univer-
sal opinion of the members present that it
was a decided specimen of the intra-capsu-
lar fracture of the cervix femoris, which had
been solidly united by bony callus. This case
may be adduced in formal contradiction to
the observation and theories of that very emi-
nent pathologist, Cruveilhier. It cannot be
said to invalidate the more guarded opinions
of Sir A. Cooper, who, in his observations upou
this subject, distinctly stated that "he would
not be understood to deny the possibility of
union, when the bone was broken, without its
periosteum and reflected ligament being torn,
or when there was no separation of its fractured
ends."

Cases such as the foregoing are certainly
rare, but they appear to the writer to belong to
the class of impacted fractures; they differ from
those alluded to in the foregoing article merely
in this, that in the former the fracture of the
cervix takes place at its basis near the trochan-
ters, and that, in the latter, the fracture occurs
near to the head of the bone, and is thus en-
tirely intra-capsular, or rather may be considered
as fractures of the intra-capsular portion of the
cervix femoris. The question then, viz. does
bony consolidation of the intra-capsular frac-
ture of the cervix femoris ever occur ? seems
to us replied to in the affirmative.

When an impaction of one, or a mutual

ABNORMAL CONDITIONS OF THE HIP-JOINT.

815

impaction of both of the fragments has taken
place, then under such peculiar circumstances
a firm bony consolidation of the fragments may
be expected.

Finally, although this is not the place to
speak of the surgical treatment of such cases,
we may remark that the most valuable practical
information, in our mind, derivable from the
discovery of facts like the foregoing, is that the
lenient method of treatment, viz. by position
alone, and without splints, may be eminently
successful, so far as the accomplishment of a
firm reunion of the fragments is concerned.

II. Luxations. — Luxations of the head of the
femur from the acetabulum are by no means so
frequent as fractures of the bones which enter
into the composition of the hip-joint.

This comparative immunity from this form
of accident arises from these circumstances, —
that the acetabulum which lodges the head of
the femur has great depth, and that the fibrous
membranes which secure this bone in the coty-
loid cavity have great strength, and restrain
within certain limits its movements. Indepen-
dently, however, of congenital luxations, and
of those which are the result of disease, there
are six distinct forms of dislocation of the hip-
joint to be described as the result of accident
alone.

The dislocations of the head of the femur from
accident may be classed as follows : — a. dislo-
cation upwards and backwards on the dorsum
ilii ; b. directly backwards towards the ischiatic
notch ; c. downwards and inwards into the
foramen ovale ; d. upwards, forwards, and in-
wards on the horizontal ramus of the pubes.
Besides these, of late years two more unusual
luxations have been described and verified by
post-moitem examinations, viz. dislocation
downwards towards the tuberosity of the
ischium, and dislocation upwards between the
anterior inferior spine of the ilium and the ilio-
pubal eminence.

a. Dislocation of the head of the femur
vpicards and backwards on the dorsum of
the ilium. — When the head of the thigh-bone
is thrown on the dorsum ilii, the limb on the
luxated side is from one to two inches
shorter than the other ; the thigh is slightly
flexed, or a little advanced upon the other, and
carried into a state of abduction, and of marked
rotation inwards. The patella and inner side
of the dislocated limb look directly inwards,
and the great toe corresponds to the tarsus of
the opposite foot. The great trochanter, carried
forwards and upwards, approaches the crest of
the ilium and its anterior and superior spine,
and forms there a very well marked tumour ;
the nates raised up by the head of the femur is
very salient towards its superior and posterior
part. If we make attempts to bring the limb
backwards into a state of extension or abduc-
tion or of rotation outwards, we find we give
much pain to the patient, and that we cannot
move the bone in any of these directions. \Ve
can, without causing suffering to the patient,
augment a little the flexion towards the abdo-
men, and adduct the dislocated thigh, and we
can also increase the rotation inwards already

existing, or, to use the words of Sir A. Cooper,
" when the leg is attempted to be separated
from the other it cannot be accomplished, as
the limb is firmly fixed in its new situation, so
far as regards its motion outwards. The thigh
can be slightly bent across the other and towards
the abdomen, but extension of the thigh and
rotation outwards are impossible." Rotation
inwards, on the contrary, is to a great extent
permitted, so much so indeed that we have
seen the back part of the heel turned forwards,
while the toes pointed backwards. During
these extreme motions of rotation inwards, if
the hand be pressed on the dorsum of the
ilium deeply, the head of the femur will be
perceived to roll on the ilium, and its tro-
chanter major also can at this time be felt to
be nearer than natural to the anterior superior
spinous process of the ilium ; the trochanter is
less prominent than that on the opposite side,
for the neck of the bone and the trochanter are
resting in the line of the surface of the dorsum
ilii. Upon a comparison of the two hips, the
roundness of the dislocated side will be found
to have disappeared. A surgeon, then, called
to a severe and recent injury of the hip-joint,
looks for a difference in length, change of posi-
tion inwards, diminution of motion, and de-
creased projection of the trochanter.

The explanation of the manner in which the
dislocation of the head of the femur upwards
and backwards on the dorsum ilii takes place
has been the subject of some difference of sen-
timent. The late Mr.Todd has, in our opinion,
given some judicious observations on this sub-
ject ;* he says, " the elementary work on luxa-
tions most generally read and referred to in
this country, is Dr. Farrell's translation of
Boyer's Lectures, arranged by Richerand. The
following is the description therein given of the
manner in which the luxation of the femur, at
present under consideration, is produced.

" When by a fall from a place, more or
less elevated, on the soles of the feet, or on
the knees, the thigh is pushed forwards and
inwards, the head of the femur, forced to-
wards the superior and external part of the
acetabulum, breaks the internal and orbicular
ligaments, escapes through the laceration in
the latter, and ascends on the external face of
the os ilium ; but as the part of the os ilium
immediately above and at the external side of
the cavity is very convex, the head of the
femur soon abandons its first position, and
slides backwards and upwards into the ex-
ternal fossa of the os ilium, following the in-
clination of the plane towards the fossa, and
obeying the action of the glutaei muscles,
which draw it in this direction. The head
of the femur, in ascending thus on the ex-
ternal face of the os ilium, pushes upwards
the glutaeus minimus, which forms a sort of
cap for it, and the glutaeus maximus and me-
dius are relaxed by the approximation of the
points into which they are inserted. The pyri-
formis is nearly in its natural state ; the gemini,
obturatores, and quadratus femoris are a little

* Dublin Hospital Reports, vol. iii. p. 397.

816

ABNORMAL CONDITIONS OF THE HIP-JOINT.

elongated. The psoas magnus and iliacus in-
ternus are relaxed, as are also the other muscles
inserted into the trochanter minor/'*

From the foregoing opinions Mr. Todd dis-
sents in the following words : — " To admit of
the head of the femur being ( forced towards
the superior and "external part of the aceta-
balum/ and of its ascending ' on the external
face of the os ilium/ it will be obvious to
those who carefully examine the mechanism of
the articulation, that the thigh must be ex-
tended on the trunk, and the dislocating force
applied externally and inferiorly, so as to pro-
duce what may be termed an excess of ad-
duction. To the limb assuming such positions,
which appear to me to be quite essential to-
wards the production of this dislocation in the
manner described by Bayer, some considerable
obstacles exist. In the first place, I believe it
seldom happens that a person who falls from a
height will reach the ground with the thigh
extended on the trunk ; in the descent the
superior power of the flexor muscles will pre-
dominate, and at the moment of the appli-
cation of force to the limb it will be more or
less in a bent position. It is scarcely neces-
sary to observe that this circumstance must
materially influence the direction in which the
head of the bone will be protruded from the
articulating cavity.

" Secondly, should the thigh and leg be com-
pletely extended at the time that the force is
applied, it is probable that the other limb will
be extended also, and will thus prevent a move-
ment of the stricken limb inwards beyond a
certain point ; or, in other words, the opposite
limb will prevent that extent of adduction
inferiorly which is necessary to remove the
head of the femur from the acetabulum, and to
admit of its being forced upon the anterior
convex surface of the dorsum ilii. But whether
the opposite limb be extended or not, it must
oppose a certain limit to adduction, if that
term can be applied with propriety to a
lateral movement of the lower extremity, by
which it is carried beyond the middle line of
the body.

" Sir Astley Cooper attributes this direction
of the limb to the circumstance of the injury
being inflicted when the knee and foot are
actually turned inwards; however, it appears
to me that muscular action is also in favour of
the limb assuming this position.

" If it be admitted that the thigh is generally
in a state of demiflexion when the force causing
this dislocation is applied, it must also be ad-
mitted that in this state the pyriformis, ob-
turatores, and gemini have but little effect as
rotators, the power of these muscles as such
being greater or less, according as the junction
of their fibres with the femur approaches
or deviates from a right angle; and that the
power of the anterior portion of the gluteeus
medius and of the tensor fasciae latae, as
rotators inwards, is increased in this position,
the angle which their fibres form with the
thigh-bone being augmented ; thus the last-

* Lectures of Boye r, p. 156.

mentioned muscles will appear to possess
much influence in determining the inverted po-
sition of the limb, as they must draw forwards
the trochanter major and external side of the
thigh, at the moment in which the head of the
bone escapes from the acetabulum.

" The inclination of the thigh forwards and
inwards which constitutes so remarkable a fea-
ture of this dislocation, may be attributed
partly to the tension of the psoas magnus, the
iliacus internus, and the pectinalis, and also
to the peculiar form of the surface of the
pelvis, to which the upper part of the femur
is applied ; but certainly not as Mr. Samuel
Cooper has asserted, to the tense state of the
triceps and gracilis, for these muscles are re-
laxed."

Anatomical characters of the luxation of the
head of the thigh-bone on 'the dorsum ilii. — The
appearances which have been noticed in the
anatomical examination of the hip-joints of
individuals who, having had a luxation of this
articulation, have died very soon afterwards
of other severe injuries received at the same
time, may be collected from the study of some
facts of this nature already published. Of
these none gives us a better idea of the recent
effects of a dislocation upwards and backwards
on the dorsum ilii than the case related by the
late Mr. Todd, in the third volume of the Dub-
lin Hospital Reports, which is as follows : —

Case. — In the summer of 1818, a robust
man, in attempting to escape from his bed-
room window in the second floor of a lofty
house, fell into a flagged area, by which acci-
dent his cranium was fractured, and his left
thigh dislocated upwards and backwards.

The dislocation was reduced without diffi-
culty ; however, an extensive extravasation of
blood having taken place on the brain, the
patient lingered in a comatose state for about
twenty-four hours, and then died. On the
day after dissection was performed, and the
following appearances were observed in the in-
jured joint and the parts contiguous to it.

On raising the glutaeus maximus, a large
cavity filled with coagulated blood was found
between that muscle and the posterior part of
the glutaeus medius. This was the situation
which had been occupied by the dislocated
extremity of the femur. The glutaeus medius
and minimus were uninjured. The pyriformis,
gemini, obturatores, and quadratus were com-
pletely torn across. Some fibres of the pec-
tinalis were also torn. The iliacus, psoas, and
adductors were uninjured. The orbicular liga-
ment was entire at the superior and anterior
part only, and it was irregularly lacerated
throughout the remainder of its extent. The
inter-articular ligament was torn out of the de-
pression on the head of the femur, its attach-
ment to the acetabulum remaining perfect.
The bones had not sustained any injury.

Cruveilhier, in the 28th and 29th livraisons
of his valuable work on Pathological Anatomy,
has given two cases of what he considers to be
old luxations of the head of the femur up-
wards and outwards on the dorsum ilii, which
had been left unreduced ; the history of these

ABNORMAL CONDITIONS OF THE HIP-JOINT.

817

cases was unknown. When we carefully ex-
amine the author's account of them, and refer
to the eight accompanying drawings he has
given of them, doubts may well arise in the
mind as to whether these are to be considered
congenital luxations, or the result of accidents
which had occurred after birth. The author
does not himself seem free from suspicion on
this rfiatter, for, in commencing his observa-
tions on the pathological anatomy of cases of
luxation of the femur on the dorsum ilii,
upwards and outwards, he says, " elles sont
tantot congeniales, tantot posterieurs a la uais-
sance. Existe-t-il des differences notables
entre les unes et les autres sous le point de
1'anatomie pathologique ? II m'est permis
d'en douter jusqu'a ce que des faits positifs
aient etabli le contraire." We have in some of
the preceding pages adduced what we have
considered positive proofs that the anatomical
characters of the congenital luxation of the hip-
joint are altogether peculiar, and the appearances
either in the living or the dead are in our
opinion by no means to be confounded with
those which are the result of luxations which
have occurred after birth, and have been left
unreduced.

When opportunities have occurred of exa-
mining the hip-joints of those who have for
many years survived a dislocation of the head
of the femur upwards and backwards on the
dorsum ilii, and which had been left unre-
duced, remarkable changes have been noticed
to have taken place in the bones and surround-
ing structures.

Muscles. — The muscles of the dislocated hip
have been found for the most part in a state
of comparative atrophy, and the direction of
their fibres has of course been altered by the
ascent of the superior extremity of the femur.
Among the muscles of the hip-joint the con-
dition of the glutaeus minimus has been most
dwelt on by authors.

It is stated on the respectable authority of
Boyer, that when the head of the femur is
dislocated upwards and backwards on the
dorsurn ilii, it passes between the external
iliac fossa, and the little glutaeus ; that it
carries this muscle up, and is as it were
capped by it (" pour ainsi dire coiffee"). This
muscle, he elsewhere adds, envelopes imme-
diately the head of the femur ; it undergoes
very remarkable changes; it becomes pale;
its fibres disappear almost entirely, and are
changed into a fibrous substance which is firm
and solid, and which has been sometimes seen
converted into bone. Cmveilhier seems to have
adopted Boyer's idea as to the change this
muscle undergoes in these cases. But if it be
true, as we believe it is, that at the moment
the luxation we are now considering occurs,
the limb is in a state of semiflexion, we
shall find it difficult to conceive how the head
of the bone in passing can encounter any of
the fibres of the glutaeus medius or minimus,
except it be the most posterior and inferior of
them.

Mr. Wallace has, in the Transactions of

VOL. ii.

the College of Physicians in Ireland,* given
a very minute and valuable account of a case
of dislocation of the head of the femur on the
dorsum ilii. The history of the case was un-
known ; but the state of the parts engaged left
no doubt on his mind that it must have been
many years since the bone had been dislocated,
and from the appearance of the body he con-
cluded that the subject was not less than fifty.
The glutaei muscles were in a state approach-
ing to that of atrophy : the posterior edge of
the glutaeus medius ran exactly over the head
of the femur; the texture of the glutaeus mini-
mus resembled adeps more than healthy mus-
cular fibre.

The pyriformis did not extend to the tro-
chanter major, but terminated at the distance
of some inches from this process, in the new
capsule which covered the head of the femur.
There was not a trace of the obturator internus,
its place having been occupied by a quantity of
fat of a peculiarly gristly texture ; the quadratus
and geraelli were pale and small, and were
bisected by an irregular tendinous line. The
direction of these muscles between their points
of attachment was more oblique than natural ;
the psoas and iliacus were diminished in size,
and their line of direction from the brim of the
pelvis to their connexion with the lesser tro-
chanter was altered, as was also the direction
of the triceps, pectinales, and obturator extei-
nus, all which were carried upwards above the
level of their usual course by the elevation of the
upper extremity of the femur on the dorsum ilii.

The femoral vessels and nerves having passed
under Poupart's ligament, were sunk into a
deep fossa, and extended backwards and out-
wards until they approached the lesser trochan-
ter ; they ran more in a serpentine or tortuous
course than the corresponding vessels of the
opposite limb ; the sciatic nerve was flattened,
its direction curved, and its vessels were vari-
cose. Its entire structure appeared as if it had
been the seat of chronic inflammation.

Ligaments. — In this case a very strong liga-
mentous fasciculus extended below the anterior
and lower part of the ilio-pubic eminence
and the lesser trochanter ; this must have per-
formed the function of a check ligament to the
motion of eversion, for any attempt at turning
the limb outwards rendered this ligament very
tense. A thick capsule surrounded the new
articulating surface of the ilium, and also the
head and neck of the femur; although the inner
surface of this was smeared with synovia, it
had not the smooth aspect of an original syno-
vial membrane. There was imbedded in the
capsule a piece of bone of a rounded figure,
half an inch in diameter.f There were no re-
mains of round ligament.

Bones. — The great trochanter was thrown
forwards with respect to the head of the bone :
the anterior internal and inferior portion of the
head of the femur was applied to the dorsum
ilii, and there was an articulating surface worn

* Vol. V. p. 252.

t Mr. W. imagined this to be a portion of the
acetabulura.

3 H

818

ABNORMAL CONDITIONS OF THE HIP-JOINT.

on the head of the femur, which marked its
point of contact with the os innominatum : the
articulating surface thus formed on the head of
the femur was very slightly convex, about one
inch and a half in diameter, smooth, whitish,
hard, and polished, though not uniformly so ;
for in some parts the bone appeared red and
porous ; the remaining portion of the head of
the femur was not opposed to bone, but applied
to the capsule which surrounded the joint ; the
head had* lost its natural rounded form, was very
irregular, and deprived of its cartilage, but
some parts of it were covered by a substance
of the nature of ligament. There were several
small pits on the head of the femur, but none
of them appeared to have been the depression
for the attachment of the round ligament.
There was an irregular ossific deposit round
the lesser trochanter.

The surface of the ilium, to which the head
of the bone was applied, was elevated half an
inch above the level of the surrounding bone,
so that this cavity appeared to have been formed
upon a plate of bone which had been planted,
as it were, on the ilium. The superior and
posterior portion of the new acetabulum, or
about two-thirds of its whole extent, was
smooth and polished, and presented a suitable
corresponding surface to receive the head of the
femur ; the aspect of the articulating surface on
the ilium was backwards, outwards, and up-
wards. There was scarcely a vestige of the old
acetabulum in its site ; there was a superficial
fossa, of a triangular form, filled with a fibrous
substance, continuous with a surrounding cel-
lular tissue. There was no articular cartilage
on any portion of the bones which formed the
new joint. There was a deep groove, one inch
in depth, formed on the outer side of the ilio-
pubic symphysis, for the lodgement of the con-
joined tendons of the psoas and iliacus muscles
in their passage over the brim of the pelvis to
the lesser trochanter.

The pelvis, in this case, was much elevated
on the side corresponding to the luxation.

b. Luxation backwards or towards the ischia-
tic notch. — The space which is called the
ischiatic notch is bounded above and anteriorly
by the ilium, posteriorly by the sacrum, and in-
feriorly by the sacro-sciatic ligament (Jig. 323).
It is formed forgiving passage to the pyriformis
muscle and to the sciatic nerve, as well as to the
great arteries, the glutaeal, ischiatic, and internal
pudendal. Its situation, with respect to the
acetabulum in the natural position of the pelvis,
is a little above its level, and it is also placed
behind it ; when the head of the bone is thrown
into this space, it is placed backwards and up-
wards with respect to the acetabulum. Therefore
though called the dislocation backwards, it is
to be remembered that it is a dislocation back-
wards and a little upwards.

In this dislocation the head of the thigh-bone
is placed on the pyriformis muscle, between the
edge of the bone which forms the upper part of
the ischiatic notch and the sacro-sciatic liga-
ments, behind the acetabulum, and a little above
the level of the middle of that cavity.

Fig. 323.

1, Pyriformis; 2, lesser sacro-sciatic ligament;
3, gemellus superior ; 4, obturator internus ; 5, ge-
mellus inferior ; 6, tuber ischii.

It is the dislocation most difficult both to
detect and to reduce ; to detect, because the
length of the limb differs but little, and its po-
sition is not much changed as regards the knee
and foot, as in the dislocation upwards ; to re-
duce, because the head of the bone is placed
deep behind the acetabulum, and it therefore
requires to be lifted over its edge, as well as to
be drawn towards its socket.

The signs of this dislocation are, that the
limb is about half an inch shorter than the
other, but generally not more than half an inch ;
that the trochanter major is behind its usual
place, but still remains nearly at right an-
gles with the ilium, with a slight inclination
towards the acetabulum ; the head of the bone
is so buried in the ischiatic notch that it cannot
be distinctly felt, except in thin persons, and
then only by rolling the thigh-bone forwards,
as far as the comparatively fixed state of the
limb will allow. The knee and the foot are
turned inwards, but not so much as in the dis-
location upwards, and the toe rests against the
ball of the great toe of the other foot. When
the patient is standing, the toe touches the
ground, but the heel does not quite reach it ;
the knee is not so much advanced as in the
dislocation on the dorsum ilii, but is still
brought a little more forwards than the other,
and is slightly bent. The limb is fixed, so that
flexion and rotation are in a great degree pre-
vented.

The following case of dislocation backwards
towards the ischiatic notch affords us a good
example of this accident. John Magee, set. 54,
a strong muscular labourer, was admitted into
Jervis-street Infirmary, 10th of November, 1831,
under my care, in consequence of his having
been severely injured in his left hip. He stated
that while carrying on his back a sack of pota-
toes, (about 3 cwt.) he unfortunately placed his

ABNORMAL CONDITIONS OF THE HIP-JOINT.

819

foot upon a round stone, which rolled from
under him, and he came down with consider-
able violence on his left knee and side ; when
raised, he was incapable of walking, and was
immediately carried to hospital. The follow-
ing morning, on examination, we made the fol-
lowing observations : while standing, the body
•was bent forwards, inclining towards the left or
affected side ; the left knee and foot were
turned inwards ; the knee somewhat more ad-
vanced and higher than the other, half flexed,
and the toes were resting on the ball of the
great toe of the opposite foot ; posteriorly, the
natis was prominent, and its lower fold was
obliterated ; the distance between the anterior
superior spinous process of the ilium and tro-
chanter major was less by one inch than be-
tween the same points on the unaffected side ;
the head of the bone could not be distinctly
felt ; the limb could be drawn inwards across
the opposite thigh, but any attempt to move it
in the contrary direction was productive of
considerable pain ; he complained of much
uneasiness in the groin (which was attributed
to the tense state of the muscles inserted into
the trochanter minor) ; the patient complained
greatly of numbness extending along the poste-
rior and outer part of the thigh and leg to the
foot. The bone was, in this case, easily re-
duced, not, however, without the assistance of
the pulleys.

This dislocation is improperly denominated
by some, luxation downwards and backwards.
Some surgeons, on the other hand, describe
cases of this accident, and yet name them dis-
location upwards and backwards on the dor-
sum ilii. Of this class, is an interesting ex-
ample published by the late Dr. Scott, of the
Armagh Infirmary, in the third volume of the
Dublin Hospital Reports. The man, the sub-
ject of the accident, died thirty -six hours after
the injury.

Dr. Scott says : — " When the patient was
lifted out of bed and placed erect, the limb
retained the posture before described ; it was
nearly two inches shorter than the other ; the
knee rested above its fellow ; the toes were
turned inwards, and lay above the opposite
instep. On viewing the hip, the trochanter
was manifestly higher on the maimed side than
the other. The hollow naturally formed behind
that process had disappeared — the buttock was
shorter and rounder, but flaccid ; the head of
the bone could not be felt through the glutaei
muscles. No effort of the patient could extend
the limb, but he had the power of bending it a
little towards the abdomen, by making the op-
posite leg a fulcrum for the inverted toes to
creep upwards upon. The dislocation was re-
duced, and he died in thirty-six hours after-
wards, in consequence of the injury some of
the organs in the abdomen received, at the same
time that the hip-joint was dislocated." It is
stated, that " on dissecting down to the hip-joint,
an extensive extravasation of blood presented
itself in the cutaneous cellular membrane, co-
vering the trochanter major, and also beneath
the fascia lata of the thigh, extending several

inches above and below the trochanter. The
glutaeus magnus being raised from its origin, a
considerable extravasation was found in the
loose cellular tissue under the glutaeus medius.
A cavity capable of containing a pullet's egg
was also brought into view. This cavity was
situated directly where the great sciatic nerve
passes under the pyriform muscle ; it contained
fluid blood ; its boundaries were the pyriformis
above, the sciatic nerve before (supposing the
body upright), the trochanter major, and insertion
of the glutaeus medius external and posterior ;
the glutaeus maximus directly posterior. Here
the displaced head of the femur had been
lodged. The fleshy substance of the gemelli
and quadratus muscles was found torn across.
The pyriformis and obturator internus were
perfect; the extravasated blood followed the
course of the sciatic nerve deep into the thigh ;
there was also extravasation between the
glutaeus medius and minimus muscles. The
internal and upper part of the capsular liga-
ment of the joint was ruptured ; the external
portion remained unbroken. On turning the
head of the bone out of its socket, the liga-
mentum teres was found to have been torn from
its insertion into the dimple of the head of the
thigh-bone; the brim of the acetabulum, at its
upper part, was fractured to the extent of about
one inch ; the fractured portion lay loose and
nearly unconnected ; a fracture traversed the
acetabulum." In this case it is manifest, from
the dissection, that the head of the bone lay
beneath even the level of the lower edge of the
pyriform muscle, as Dr. Scott states that the
boundaries of the cavity (capable of containing
a pullet's egg, and filled with coagulated
blood,) which no doubt was the new situation
that the head of the dislocated femur for a time
rested in, — that the boundaries of this cavity
were "the pyriformis above," Sec. The dis-
section we consider a valuable one, adding
something to our knowledge of the anatomical
characters of the luxation into the ischiatic
notch ; differing, however, in some few particu-
lars, from that of Sir A. Cooper, Dr. Scott's, it
is to be recollected, was the dissection of a case
in which the bone had been only a few hours
misplaced. When we analyse the previous
symptoms of Dr. Scott's case, we do not, it
must be confessed, read the characteristic fea-
tures detailed of the dislocation backwards ;
still the pain the patient suffered along the
course of the sciatic nerve rather pointed the
attention to a dislocation on the sciatic notch,
than to the ordinary one of dislocation upwards
on the dorsum ilii, in which the nerve is
not, at least directly, interfered with; and the
observation added, that " the head of the bone
could not be felt through the glutaei muscles,"
also would lead us to infer that among many
of the symptoms this patient laboured under,
some were such as would lead us to suspect
that the luxation was that backwards towards
the sciatic notch, a suspicion that, in the wri-
ter's mind, the dissection given by Dr. Scott
would fullyjustify.

We suspect, also, that one of the cases
3n 2

ABNORMAL CONDITIONS OF THE HIP-JOINT.

820

published by Mr. Bransby Cooper* as one
of dislocation on the dorsum ilii, was ra-
ther the dislocation we are now considering,
namely, the luxation towards the ischiatic
notch. Among some of this patient's symp-
toms, it is mentioned that the trochanter major
was plainly felt behind and a little above the
natural situation with respect to the ilium ; the
head of the bone could be felt neither in the
sitting, standing, nor lying posture. Indeed,
Mr. B. Cooper himself remarks that, " upon
taking into consideration all these diagnostic
marks, I was induced to consider the acci-
dent a luxation on the dorsum of the ilium;
although the head of the bone was not drawn
up so high as usual, as indicated by the slight
shortening of the limb; and the trochanter
major was also drawn further backwards than
is usual, in the dislocation on the dorsum, so
that, perhaps, this might by some surgeons have
been described as a dislocation to the ischiatic
notch." Mr. Cooper further adds : — "I doubt,
however, if this appellation as applied to a cer-
tain variety of dislocation of the hip, does not
rather mystify than facilitate our diagnosis,
for it leads to the supposition that the head of
the bone sinks into the osseous hiatus, — a cir-
cumstance which could not occur even in the
skeleton itself, from the size of the head of the
bone, and much less could it happen in the
living subject, when this notch is filled up
with ligaments, muscles, vessels, and nerves."
This respectable surgeon proposes, therefore,
to expunge from the classification of dislocations
the luxation into the notch, but to consider it
only as a variety of the dislocation on the
dorsum ilii, distinguishing the one as a luxation
upwards, the other backwards, on the dorsum.
To this proposition we cannot by any means
assent, for we consider that a dislocation back-
wards behind the ischium, and to the ischiatic
notch which is below the level of the ilium,
never can be properly designated a variety of
the dislocation on the dorsum ilii, although we
might assent to the proposition to consider it a
variety of the dislocation backwards. The
case as described by Sir A. Cooper, of disloca-
tion on the sciatic notch, we are satisfied is to
be seen occasionally, though rarely, in the living;
and the dissection made by Sir Astley himself,
in which he found the head of the bone resting
behind the acetabulum on the pyriform muscle,
tlie preparation of which is to be found in the
museum of St. Thomas's Hospital, should,
we imagine, place the matter beyond dispute.

Anatomical characters. — We have, says Sir
Astley Cooper, a good specimen in the collec-
tion of St. Thomas's Hospital, which I met
accidentally in a subject brought for dissection.
The original acetabulum is entirely filled with a
ligamentous substance, so that the head of the
bone could not have been returned into it. The
capsular ligament is torn from its connection
with the acetabulum at its anterior and posterior
junction, but not at its superior and inferior.
The ligamentum teres is broken, arid an inch of

* Guy's Hosp. Reports, Jan. 1836.

it still adheres to the head of the bone. The
head of the bone rests behind the acetabulum,
on the pyriformis muscle, at the edge of the
notch above the sacro-sciatic ligaments. The
muscle on which it rests is diminished, but
there has been no attempt made to form a new
bony socket for the head of the os femoris.
Fig. 324.

Around the head of the thigh-bone a new
capsular ligament is formed ; it does not adhere
to the articular cartilage of the ball of the
bone which it surrounds, but could, when
opened, be turned back to the neck of the
thigh-bone, so as to leave its head completely
exposed.

Fig. 324.

Luxation in the sciatic notch.*

Within the new capsular ligament, which is
formed of the surrounding cellular membrane,
the broken ligamentum teres is found. The
trochanter major is rather behind the acetabu-
lum, but inclined towards it relatively to the
head of the bone. This dislocation, he adds,
must have existed, from the appearances of the
parts, many years. The adhesions were too
strong to have admitted of any reduction, and
if reduced, the bone could not have remained
in its original socket.

c. Luxation upwards and inwards on the
pubcs. — This luxation is more easy of detection
than any other of the thigh. It happens from a
person while walking putting his foot into
some unexpected hollow in the ground, and
his body at the moment being bent backwards,
the head of the bone is thrown forward upon
the os pubis.

The limb in this species of dislocation is
an inch shorter than the unaffected one; the
knee and the foot are turned -outward, and

* From Sir A. Cooper, pi. iv. on Fractures and
Dislocations.

ABNORMAL CONDITIONS OF THE HIP-JOINT.

cannot be rotated inwards, nor flexed with-
out causing acute suffering. The inguinal
region is the seat of the principal pains, which
however from this point extend along the thigh,
and are the consequence of the stretching which
the anterior crural nerve necessarily suffers as
it is raised up at the neck of the bone.

The striking criterion of this dislocation is,
that the head of the thigh-bone may be dis-
tinctly felt upon the pubes, above the level of
Poupart's ligament, and it feels as a hard ball,
which is readily perceived to move by bending
the thigh-bone. The femoral artery has been
usually felt pulsating along the inner side of
the head of the bone, but Mr. Smith presented
lately to the Pathological Society the cast of
a case of this luxation, in which he had noticed
that the femoral artery ran in a tortuous
manner directly across the head of the dislo-
cated bone.

The great trochanter is drawn upwards and
forwards, so as to be situated in the trajet of a
line which would pass from the anterior infe-
rior spine of the ilium, downwards and for-
wards. In a case of a dislocation of this spe-
cies which was left a long time unreduced, the
motion of the knee backwards and forwards
was fully twelve inches. The following case
was admitted into Jervis Street Hospital, under
the care of Mr. O'Reilly, during the time I
was one of the surgeons to that institution, and
as it seemed to me the best marked case of the
kind I had ever witnessed, I beg here to lay it
before the reader from my case-book.

Case, — P. Bryan, a powerful man, aged 37,
was admitted into Jervis Street Infirmary,
Dec. 4, 1828. He was intoxicated when the
accident which produced the luxation occurred,
and consequently was unable to give any idea
as to how the injury was produced.

As the patient lay on his back in bed the
affected limb appeared to lie parallel to its
fellow, but then there was an eversion of the
whole limb, and the foot of course turned out-
wards. One circumstance particularly caught
our observation, viz. the preternaturalfy arched
appearance which the upper third of the shaft
of the femur presented ; the adductor muscles
were full and prominent; there was an unusual
prominence underneath Poupart's ligament;
the anterior superior spinous process appeared
retired.

On making more minute examination it was
found that the eversion of the foot was perma-
nent, and we were surprised to find that there
was but little difference between the length of
both limbs ; certainly the injured one was little
more than half-an-inch shorter than the sound
one. A considerable depression existed where
formerly the trochanter major lay ; this process
of bone was very evident, and could be readily
felt about two inches below and somewhat
anterior to the anterior superior spinous pro-
cess of the ilium, and about the same distance
internal to it a wrell-marked prominence in the
inguinal region shewed the new situation which
the head of the femur occupied ; along its
inner side were seen and felt the pulsations of

821

the femoral artery. On communicating a
motion of rotation outwards, the head of the
bone could be easily felt under the soft parts ;
the nates was flattened ; the femur was but
little moveable with respect to the pelvis, and
any attempt to draw the thigh backwards
caused great pain to the patient : to flex it was
impossible. A motion of rotation outwards
could be communicated to the dislocated femur,
but no rotation inwards was permitted. Ad-
duction of the limb was admissible, even to
permit the knees to touch. When the patient
stood up, he naturally threw his weight on the
sound limb, and the affected one was flexed
slightly at the knee, and the heel touched the
inside of the opposite foot, as in the "first
position" of dancers. The reduction of the
dislocation was effected in the ordinary method ;
indeed the rules laid down by Sir. A. Cooper
were fully adopted, and in due time succeeded.
Anatomical characters of this luxation. —
Sir. A. Cooper gives us an account of the dis-
section he made of one of these luxations of the
femur on the pubes, which had been a long
time unreduced; he found the original ace-
tabulum partially filled by bone, and in part
occupied by the trochanter major, and both are
much altered in form ; the capsular ligament is
extensively lacerated, and the ligamentum teres
broken. The head of the thigh-bone had torn
up Poupart's ligament, so as to be admitted
between it and the pubes (Jig. 325). The head

Fig. 325.

Luxation on the pubes^

and neck of the bone were throwa igtto a position
under the iliacus internus and psoas muscles,
the tendons of which, in passing to their in-
sertion over the neck of the bone, were elevated
by it and put on the stretch. The crural nerve
passed on the fore-part of the neck of the bone,

* From Sir A. Cooper, loc. cit. plate v.

822

ABNORMAL CONDITIONS OF THE HIP-JOINT.

upon the iliacus interims and psoas muscles.
The head and neck of the thigh-bone are
flattened, and much changed in their form.
Upon the pubes a new acetabulum is formed
for the neck of the thigh-bone, for the head of
the bone is above the level of the pubes. The
new acetabulum extended upon each side of
the neck of the bone, so as to lock it in a cer-
tain direction upon the pubes. Poupart's
ligament confines it on the fore-part ; on the
inner side of the neck of the bone passed the
artery and vein, so that the head of the bone
was seated between the crural sheath, and the
anterior and inferior spinous process of the
ilium.

d. Luxation downwards and inwards into the
foramen ovale. — When the femur is in a forced
state of abduction, if violence be in any man-
ner applied so as still further to exaggerate this
movement, the head of the femur having pre-
viously glided from above downwards in the
acetabulum to its utmost, applies itself to the
interior of the capsular ligament, which it
stretches ; if the force be continued the capsule
soon gives way, and the head of the femur,
bursting through the rent, is dislocated and
lodged in front of the obturator foramen.

The symptoms by which we recognize this
accident are very well marked, as the limb in
this dislocation is two inches longer than the
other. The body is bent forwards owing to the
psoas and iliacus interims muscles being put
upon the stretch (Jig. 326). The knee is consi-
derably ad vanced ; if the body be erect it is widely
separated from the other, and cannot be brought
without great difficulty towards the middle line
or made to touch the other knee, owing to the
extension of the glutsei and pyriform muscles.
The foot, though widely separated from the
other, is generally neither turned outwards nor
inwards, although it varies a little in this respect
in different instances, but the position of the
foot does not in this case mark the accident.
The adductor muscles are elongated and form
a round prominent line which extends from the
pubes to the middle of the thigh. The foot
and the knee are turned outwards because the
adductor and the other muscles which execute
the movement of rotation outwards are on the
stretch and elongated. The thigh cannot be
adducted, and when we wish to communicate
this movement to the limb the patient feels
severe pains because of the tension which the
glutaei and rotators outwards suffer. The reason
of the flexion of the leg is two-fold ; first to
relax the hamstring muscles which are put
upon the stretch by the dislocation, and to
establish an approach to an equality in the
length of the limb.

When we examine closely the injured hip,
we notice a considerable hollow at the upper
and outer part of the thigh where the great
trochanter is normally seen projecting, and a
depression is noticed below the centre of Pou-
part's ligament. The head of the dislocated
bone can be felt occasionally at the inner and
outer parts of the thigh towards the perineum.
The position of the head of the bone is below

Fig. 326.

Luxation into the foramen ovale.

the acetabulum and a little anterior to it. The
bent position of the body, the separated knees,
and the increased length of the limb constitute
the striking and characteristic features of this
rare accident.

That excellent practical surgeon, Mr. Hey
of Leeds, had not during a period of public
and private practice for thirty-eight years seen
a case of this accident of luxation downwards
and inwards into the foramen ovale, until in
the year 1797 three patients were brought into
the infirmary of Leeds. In one of the best
marked examples of this accident the dislocated
thigh appeared much thicker at the superior
part than the other; the adductor muscles, it
appears, were upon the stretch, and the inguinal
hollow we can collect was effaced (perhaps by
the tension of the skin and effusion). Mr. Hey
says, the head of the bone could not be dis-
tinctly felt through the muscles ; yet, from the
appearance and the touch, it was sufficiently
evident that the head of the bone lay upon the
great foramen of the os innominatum. It
seemed probable that it had passed so far from
the acetabulum as to be in contact with the
descending part of the os pubis.

There was in this case a considerable hollow
at the upper and outer part of the thigh where
the great trochanter is usually felt projecting.

The following case of dislocation of the

ABNORMAL CONDITIONS OF THE HIP-JOINT.

823

femur into the foramen ovale I saw in Steevens's
Hospital, and my friend Dr. Osbrey has obliged
me with his notes of the case, which were as
follows : —

Michael Murphy, set. 21, a labourer, ad-
mitted June 4th, 1834, under Mr. Colles with
dislocation of the head of the femur into the
foramen ovale.

He stands with his entire weight upon the
sound side, the left thigh flexed on the pelvis,
his knee bent, and toes turned out and resting
on the ground, from which the heel is raised ;
the thigh is abducted so that he cannot bring
his knees nearer than within five inches of
each other, when standing up not within nine,
and at this time his toes are thirteen inches
asunder; the thigh is wasted, and he cannot
support any weight on the limb. When asked
to walk without support he places his hand
firmly on the knee, and bears his weight on
the arm and leg without throwing any of it on
the thigh. His pelvis is lower on the injured
side, and there is a slight curvature of the
spine, the convexity to the same side, in conse-
quence of which there is great apparent length-
ening of the limb. The real difference when
measured from the symphysis pubis to the point
of the inner ankle is two inches and a half, but
there is little or no difference when measured
from the spine of the ilium ; and when the
measurement is taken from the tuber ischii the
dislocated limb is two inches longer than its
fellow. There is considerable deformity about
the joint; a deep hollow exists immediately
below the anterior spine of the ilium, through
which the sartorius runs obliquely, joining a
prominent ridge when the muscle is in action.
The prominence of the trochanter is altogether
lost, and that process can be with difficulty
felt. The fold of the buttock is completely
obliterated, and there is a fullness towards the
upper and back part of the thigh, caused by
the head of the bone, which can -be felt through
the adductor muscles, and seems to be situated
further inwards than is usually described in
this accident. He states that he received the
injury five weeks ago; he was thrown down on
his right side obliquely against a wall, by a
horse running away with a cart, and the wheel
of the cart passed over his left hip above the
trochanter ; he felt great pain at the time which
was chiefly referred to the inside of the knee.
He was carried home and nothing was done
for him for a fortnight, when he went to a
hospital, where several attempts were made at
reduction ; all, however, failed, and after re-
maining there a fortnight longer he came up to
Dublin in the state above described.

On the 12th of June two attempts to reduce
the bone failed altogether, and the man returned
to the country.

Anatomical characters. — It seems probable
that the head of the dislocated femur passes so
much forwards and inwards from the acetabu-
lum as to be in contact with the inner margin
of the thyroid foramen, where this foramen is
completed by the rami of the ischium and
uubes. The convexity of the great trochanter

has the acetabulum behind it, and the lesser
trochanter is placed immediately external and
anterior to the tuberosity of the ischium. The
ligamentum teresand lower part of the capsular
ligament have been torn through, and the head
of the bone " become situated in the interior
and inner part of the thigh upon the obturator
externus muscle."

We have, says Sir Astley Cooper, an ex-
cellent specimen of this accident in the collec-
tion of St. Thomas's Hospital, which I dissected
many years ago. The head of the thigh-bone
was found resting on the foramen ovale, but
the obturator externus muscle was completely
absorbed, as well as the ligament naturally
occupying the foramen now entirely filled by
bone. Around the foramen ovale bony matter
was deposited so as to form a deep cup, in
which the head of the thigh-bone was inclosed,
but in such a manner as to allow considerable
motion ; and the cup thus formed surrounded
the neck of the thigh-bone without touching it,
and so enclosed its head that it could not be
removed from its new socket without breaking
its edges. The inner side of this new cup was
extremely smooth, not having the least ossified
projection at any part to impede the motion of
the head of the bone, which was only restrained
by the muscles from extensive movements.

The original acetabulum was half filled by-
bone, so that it could not have received the
ball of the thigh-bone if it had been put back into
its natural situation (fig. 327). The head of the
thigh-bone was very little altered, its articular

Fig. 327.

Luxation into the foramen ovale.*
* From Sir A. Cooper, pi. ii.

824

ABNORMAL CONDITIONS OF THE HIP-JOINT.

cartilage still remained, the ligamentum teres
was entirely broken, and the capsular ligament
partially torn through. The pectinalis muscle
and adductor brevis had been lacerated, but
were united by tendon. The psoas muscle and
iliacus internus, the glutsei and pyriformis, were
all upon the stretch.

e. Cases of unusual dislocations. — In (Guy's
Hospital Reports we find the account of two
cases of dislocation of the head of the femur
upwards and outwards towards the anterior
superior spinous process of the ilium.

In the first of these cases, detailed by Mr.
Morgan, the affected leg (the left) was short-
ened to the extent of at least two inches, the
foot was excessively everted, so much so as
almost to give the toes a direction backwards.
The injured limb had a tendency to cross that
of the opposite side, so that the heel was thrown
over the instep of the opposite foot; neverthe-
less when the feet were placed side by side,
they remained in that position. The limb was
susceptible of all the natural motions to some
extent, with the exception of rotation, but the
man complained of great pain when under ex-
amination. The projection of the trochanter
major was entirely lost, whilst the luxated head
of the bone might be felt under Poupart's liga-
ment, just below and to the inner side of the
anterior superior spinous process of the ilium,
and it apparently lay between the anterior and
inferior spinous process of the ilium, and the
junction of this last bone with the pubes ; it
thus rested upon the brim of the pelvis, and
projected upwards towards the abdomen ; the
femoral artery was not displaced in this dislo-
cation, but could be traced taking its usual
course, and consequently situated to the inner
side of the displaced bone.

In this case a speedy reduction of the dislo-
cated bone was effected, but in the second case
I have alluded to, the bone was left unreduced
for years. We are indebted for the publication
of the whole case, accompanied with the dis-
section, to Mr. Bransby Cooper, who tells us
that the preparation which illustrates the acci-
dent the patient suffered from, was presented to
Sir Astley Cooper, by his friend Mr. Old-
know of Nottingham, and the bones are pre-
served in the museum of Guy's Hospital. The
subject of the accident was a lunatic, aged 28,
and as far as we can learn from the detail of
the case given, his symptoms were very much
those which Mr. Morgan's patient presented
before the dislocation was reduced.*

Upon dissection it was found that the old
acetabulum was deprived of articular cartilage,
and was in part filled up by bony deposit, so
as to be rendered wholly unfit for the reception
of the head of the femur. The new acetabulum
was nearly directly above the original cavity,
and was bounded on the outside by the two
anterior spinous processes, and on the inside by
the line of junction of the ilium and the hori-
zontal branch of the pubes, that is to say, by
the ileo-pubal eminence. The form of the new

* Guy's Hospital Reports, January, 1836, p. 99.

cavity for the reception of the head of the femur
was very like the natural acetabulum, but not
quite of equal dimensions ; it is protected above
by a growth of bone which overlapped the head
of the femur, and must have formed the princi-
pal point of support of that bone. The inferior
part of the new acetabulum was the most defi-
cient. The trochanter major sunk partly into
the old acetabulum, and polished points on both
the old and new acetabulum indicated where
the head of the femur and trochanter major
played in the various motions this imperfect
joint enjoyed.

We are not informed how the muscles were
altered from their normal state, but may infer
that most of them were more or less atrophied ;
it is probable, however, that both the obturator
externus and internus were put much iipon the
stretch, and retained the bone more or less
downwards. It would have been interesting to
have learned the precise situation of the rectus
femoris, tensor vaginae, and sartorius, psoas,
and iliacus, but we can easily imagine that
the latter were much shortened, and that they
were raised up from the pubes by the dislocated
bone, the tendon of the rectus must have been
thrown outwards over the rest of the femur and
trochanter major. The head of the femur was
altered from its original figure, so as to be
adapted to the new acetabulum, portions of it
being diminished where it did not come in con-
tact with the new cavity, so that its spheroidal
figure was lost. The periosteum of the femur,
as well as of the new acetabulum, assisted in
forming the new capsular ligament. The arti-
cular cartilage of the head of the femur has
been absorbed, and the same porcelain-like
concretion, as is seen in the acetabulum, is
provided at corresponding points. From the
form of the articulating surfaces, and the fixed
position of the femur, both at the head and the
trochanter major, it will be observed that no
other motion than flexion could be permitted,
and even that motion, from the closeness of the
attachment at the trochanter, but to a limited
extent.

Luxation of the head of the femur down-
wards and backwards. — This luxation may
be considered as a very rare accident. When
the last edition of Sir A. Cooper's work on
Fractures and Luxations was published, the
baronet had not seen such an accident, as he
remarked, " it is to be remembered that there
is no such accident as a dislocation of the hip
downwards and backwards."

Dupuytren says, " I have only twice or thrice
seen this luxation downwards and backwards.
The limb was then twisted inwards, a little
elongated, and it was impossible to adjust it to
its ordinary place and position, without reducing
the luxation, which once accomplished, the dis-
placement did not a second time recur/'

My friend Mr. Wormald, assistant-surgeon
to St. Bartholomew's Hospital, has published an
account of an accident of this kind in the Medical
Gazette, June 28, 1837, and the preparation,
which shews the relative .position of the head
of the dislocated bone, See. and the acetabulum,

HYPERJEMIA AND ANEMIA.

825

is preserved in the museum of the hospital.
Fig. 328.

Fig. 328.

Dislocation downwards and backwards.
B, obturator intermix ; C, trochanter major; D,
the acetabvlvm ; E, obturator externus ; F, sciatic
I, shaft of the femur.

" A maniac who eluded the vigilance of his
keepers, leaped from a third story window.
Besides dislocating his thigh, he received other
injuries, of which he died in about an hour.

" On examining the dislocated limb, it was
found considerably shortened and inverted,
forming about half a right angle with the body,
the shaft of the femur crossing the symphysis
pubis was fixed immoveably in this situation ;
as the patient was sinking, no attempt was
made at reduction.

" Twelve hours after the death of the patient
I commenced the dissection, by reflecting the
glutaeus maximus, when I found some of the
fibres of the glutaeus medius and minimus rup-
tured at their posterior edge. The pyriformis
and gemelli were also partially torn, but those
portions of the tendon of the obturator interims
which pass through the lesser ischiatic notch
were drawn out, and separated from their con-
nexion with the muscular fibres ; the head of
the femur presented itself through a rent of the
capsule, opposite to the upper part of the tuber
ischii above the quadratus, so that the great
sciatic nerve was somewhat displaced and
pressed against the tuber ischii.

" In this case there was no difficulty in de-
tecting the nature of the injury, as, besides the
symptoms already described, the head of the
femur could be felt resting on the tuber ischii,
covered by the outer edge of the glutaeus maxi-
mus.

" If this patient had been in a condition to
attempt reduction of the dislocation by fixing
the pelvis, and employing extension in the
direction of the shaft of the bone, at the same
time everting the limb, the head of the femur
would have been brought opposite the rent in
the capsule, and would have been in all pro-

bability replaced in the acetabulum without
greater difficulty than is usually experienced."
(Robert Adams.)

HYPEILEMIA AND ANEMIA, (vvs?r
super; a, negative; and at/xa, sunguis) (in
morbid anatomy). These are terms employed
to denote opposite conditions of the various
membranous or parenchymatous textures of the
body as regards the quantity of blood contained
in their bloodvessels ; the former, as its deriva-
tion denotes, indicating a superabundant sup-
ply of blood, the latter a deficiency of that
fluid. They are useful terms to the anatomist,
inasmuch as they express simply the state of a
texture, without any theory being involved
respecting the cause or origin of that state.
It ought always to be the first business of the
anatomist to observe carefully the actual con-
dition of the parts submitted to his examination;
this having been done, he should search dili-
gently for some cause, mechanical, chemical, or
vital, which will satisfactorily account for the
phenomena.

All vascular textures, it is obvious, are liable
to these conditions; and it is equally evident
that the relative frequency of their occurrence
in different textures will coincide with the
natural facility of the flow of blood to or from
them, as well as the quantity of blood con-
tained in them in the normal state. Thus the
lung or the spleen is favourable for the forma-
tion of hypersemia, as well from the large
supply of blood in each as from the free com-
munication between their respective arterial and
venous systems, and between the ramifications
of vessels of the same kind.

A bleached state of the same organs may be
taken as a good example of the opposite con-
dition, or anaemia; but the most complete
anaemia is, of course, to be found in organs or
tissues which, in the natural state, contain but
a small quantity of blood.

It is important to notice that hyperaemia may
occur independently of disease and altogether
as a cadaveric phenomenon, and there is no
mistake more frequently committed by the
incautious observer than that of attributing to
the influence of a morbid process during life
appearances which simply result from the
ordinary physical laws which death has allowed
to exert full sway over the tissues. Indeed, it
is only since anatomists have ceased to regard
every instance of an unduly injected tissue as
a diseased one, that valuable practical conclu-
sions have been drawn from post-mortem obser-
vations.

We may pronounce hyperaemia not to be mor-
bid, when it is found to occupy only the most
dependent parts of organs, the blood having
deserted the vessels of the more elevated parts.
At every post-mcrtem examination we have
abundant examples of hyperaemia of this kind ;
if the body have been laid on the back, as is
usually the case, the whole of the skin of that
region is largely injected with blood; the sub-
cutaneous cellular tissue is in a similar condi-
tion, and the adjacent muscles more or less so

826

HYPERTROPHY AND ATROPHY.

likewise. The blood in these cases is chiefly
contained in capillaries and veins, the ramifica-
tions of which will be found fully injected.
The dependent parts of all the vascular tissues
and organs of a body thus placed, exhibit
similar appearances. The scalp on the occiput,
the posterior lobes of the brain, and the
cerebellum are much more injected than the
anterior parts of the same textures. The pos-
terior parts of the lungs, of the stomach and
intestines, of the spleen, liver, and kidneys
exhibit the same state of vascular congestion.
That this results altogether from position and
the blood in the vessels obeying the universal
law of gravitation, may be clearly proved by
reversing the position of the body, when after
a little time the blood will desert the former
dependent but now elevated parts, and those
portions of the texture which before were almost
devoid of blood from their elevated position,
now have their vessels filled with it.

When hyperaemia results from a mechanical
obstacle to the circulation, it is not accumulated
at one part of an organ or viscus, but all parts
appear equally gorged with the blood. In
certain diseased states of the heart and liver,
the intestinal canal presents an example of this
general hyperaemia, owing to the mechanical
obstacle to the free circulation of the blood in
the right heart. The circumference of the
intestine is every where reddened by the blood
accumulated in its capillaries.

Audral, by whom of late years the term hy-
peraemia itself was brought into use in morbid
anatomy, gives the following varieties of it.
1. Active or sthenic hyperaemia, denoting the
state indicated by the ordinary expression
acute inflammation. 2. Passive or asthenic,
resulting from diminished tone in the capil-
jary vessels. 3. Mechanical, from an obstacle
to the venous circulation. 4. Cadaveric or
post-mortem, being the result of those physical
and chemical laws to which all inorganic
matter is subject, and to which all organized
bodies are also subjected when the vital spark
has ceased to animate them.* This last variety,
moreover, he subdivides into two genera.
First genus, hyperaemia produced at the mo-
ment of death. — Cause; the contractility of
tissue which resides in the small arteries, con-
tinuing to act after the heart has ceased to beat.
Second genus, hypersemia produced at a certain
period after death. This genus comprehends
the following species: — 1. Hyperaemia by hy-
postasis or dependent position. 2. Hyperaemia
by transudatton of the blood or of some of its
component parts through the parietes of its
vessels. 3. Hyperaemia by chemical affinities.

Anamia, a term long in use to express a
general exsangueous and cachectic condition
of the body, is also applied to a local state
of exsangueousness. Any cause which would
impede or cut off the wonted supply of blood
to a part will occasion this condition in it ; the
diminution in the calibre of the principal artery
of an organ, from mechanical pressure or disease

* Path. Anat. by Townscnd, vol. i. p. 15.

in the vessel, or a depressed state of the nervous
influence. Hyperaemia of one organ may give
rise to anaemia of another, the former as it
were attracting the blood away from the
latter.

The general condition of anaemia is not un-
frequently brought under the physician's notice
either as the result of some excessive and long-
continued hemorrhage or of some deranged
state of general nutrition, giving rise to a deterio-
ration in the quality of the blood, or a general
deficiency in the powers of the nervous in-
fluence. The surface of the body is pale, the
mucous membranes, as far as they can be seen,
partake of the same exsangueous state, the
secretions are defective and vitiated, the tone
of the muscular and vascular systems is con-
siderably diminished, and this state may go on
without any specific morbid change in any
organ, beyond its participation in the general
scanty supply of the blood, or it may co-exist
with an organic disease, which, although it
may have been at first the result of the primary
exciting cause of the anaemia, now serves to
increase it, or offers the greatest impediment to
its removal.

(R. B. Todd.)

HYPERTROPHY AND ATROPHY,

super ,a,priv., and Tge<pu,nutrio},(in morbid ana-
tomy). When any organ or tissue has acquired
a certain increase of developement, without
any manifest alteration of its natural structure,
it is said to be in the state of hypertrophy —
the increase being due to a greater activity
of the nutritive process in the part affected.
A familiar example of hypertrophy, although
not morbid, is afforded by the augmentation
which muscular fibre acquires in consequence
of increased action. If the biceps muscle of
one arm be actively exercised, while that of the
other does not undergo any considerable degree
of action, the former acquires a great increase
of size, it becomes denser and firmer, and
manifests the physical and vital phenomena of
the muscular tissue with more than ordinary
energy.

There is no texture in the body which does
not occasionally exhibit evidence of the hyper-
trophous condition. The circumstances which
favour its production are an abundant and a
free afflux of blood to the part, an energetic
nervous influence and an increased demand
upon the organ, or increased exercise if it be
muscular; and indeed these are the almost in-
variable conditions under which hypertrophy is
manifested. The heart becomes hypertrophous
under an exalted nervous influence, or from a
necessarily increased exercise from the effort to
overcome some obstacle to the free circulation of
the blood through its cavities ; one kidney
acquires a great increase of size if the other
one be incapable of performing its function.
It may be said that the liver is in a state of
hypertrophy in the foetus in utero, for it has
a larger supply of blood than in extra-uterine
life, and the lungs have not as yet begun to
share with it in the office of decarbonizing the

ILIAC ARTERIES.

827

venous blood. The bladder also, like the
heart, acquires an enormous developement of
its muscular coat, when any obstacle obstructs
the free flow of the urine from it. The physi-
cal condition, then, of a hypertrophous organ
differs but in degree from that of the part in
its normal state. There are, in general, in-
crease of size, of weight, and of consistence,
with more or less alteration of shape consequent
upon the former ; an increased supply of blood,
and a consequent heightening of colour. To
judge therefore how far an organ has experi-
enced hypertrophy, the anatomist must care-
fully compare its present condition, as regards
size, weight, colour, consistence, and supply
of blood, with the average state of the parts in
health.

Atrophy is not only opposite in its nature to
hypertrophy, but it results from causes of an
entirely opposite kind. A defective state in
the nutritive process is its immediate cause : —
the affected part shows manifest signs of wast-
ing ; it diminishes in size and in consistence ;
it loses its colour from the deficient supply of
blood ; its physical and vital properties are
manifestly altered, and are fully developed.
When the wasting has gone to its greatest ex-
tent, the natural texture disappears, or is so
altered as to present but few of the characters
of its normal condition. As frequent exercise
and use favour the production of hypertrophy,
so on the other hand disuse and inactivity
give rise to atrophy. Neither the vascular nor
the nervous systems of such parts afford their
wonted supplies ; and those physical characters
which are present in hypertrophy in an exalted
condition, are in atrophy either absent altoge-
ther, or but feebly developed. The muscles
of paralytic limbs, the hearts of old persons
which have been overloaded with fat, the
diminution in size and almost total disappear-
ance of the thymus gland in the adult, the
diminution of the left lobe of the liver in extra-
uterine life, the obliteration and conversion into
a fibrous cord of certain disused venous and
arterial canals, and the wasting of the optic
nerve where the eye is destroyed, are examples
of atrophy of every day's occurrence. (See the
articles on the morbid anatomy of the different
textures and organs.)

( R. B. Todd.)

ILIAC ARTERIES* (so called from their
situation in the iliac regions) are three upon each
side of the body, viz. the primitive iliac, the
internal and the external iliacs ; they are the
main arteries of the pelvis and the lower ex-
tremity.

PRIMITIVE ILIAC ARTERIES (common iliacs,

* But little dissection is necessary to display the
iliac arteries ; the abdominal wall having been di-
vided and thrown back, the peritoneum may be
detached from without inward, along with the con-
tained viscus, from the iliac fossa, which having
been done to a sufficient extent, care being at the
same time taken to leave uninjured the spermatic
vessels the vas deferens and the ureter, the iliac
arteries will be exposed still covered by their imme-
diate investment.

arteria iliacee primitive, s. communes, s.pelvi-
crurales; Fr. Arttresiliaques primitives; Germ.
Gemeinschqftliche HuJ't-pulsadern,) are two,
one on each side : they are vessels of great
size, from three-eighths to four-eighths of
an inch in diameter, but short, their length
varying from one and a half to two and a half
or three-quarters of an inch, the arteries being
longer or shorter, according to the height
at which the aorta divides. They arise from
the termination of the aorta, their origin
corresponding, as a mean point, to the in-
terval between the bodies of the fourth and
fifth lumbar vertebrae, and somewhat to the
left of the middle line of the vertebral
column ; the exact height of their origin,
however, varies considerably, ranging in ordi-
nary between the bodies of the third and
fifth vertebrae ; but they have been found to
arise very near to the diaphragm.* From their
origin they descend, and at the same time in-
cline outward and backward, forming with each
other an acute angle, but more so in the male
than in the female subject, because of the
greater width of the pelvis in the latter, until
they reach a point ranging between the body of
the fifth lumbar vertebra and the sacro-iliac
articulation,^ where they terminate by dividing
into the internal and external iliacs. The point
of reference usually assigned for this division is
the sacro-iliac articulation ; but this appears not
to be strictly correct, the exact point varying as
well on the opposite sides of the same as in
different subjects ; for the most part the division
takes place between the two points, which have
been mentioned ; at times nearer to one, at
times to the other, and according to Velpeau,
it usually occurs nearer to the spine upon the
right than upon the left side ; hence, according
to the same authority, the right external iliac
artery is longer than the left, and were it pos-
sible to ascertain these diversities of origin
during life, advantage would result therefrom,
inasmuch as the prospect of success in high
ligature of the external iliac must be influenced
by the height of its origin, and the difficulty of
reaching the primitive or the internal iliacs must
be increased in the same proportion. These
views appear well-founded ; the division of the
primitive iliac rarely takes place so far outward
as the sacro-iliac articulation, and for the most
part it is nearer to the body of the vertebra, or
higher upon the right than the left side, and
therefore the external iliac of that side is usually
the longer, but this disposition is not constant ;
the division of the right primitive artery is not
always higher than that of the left, nor conse-
quently the right external longer, and therefore
while probability is in favour of the conclusion
which the facts stated indicate, it cannot be
absolutely relied upon.

The primitive iliac arteries are of the same
size, and nearly the same length; the right,
however, is considered for the most part some-
what the longer, because of the situation of the

* Velpeau, who cites Petsche on the authority of
J. F. Meckel.
t Bogros.

828

ILIAC ARTERIES.

aorta upon the left side of the spine ; Velpeau,
however, seems to question the existence of any
difference in the length of the two vessels, inas-
much as the right divides generally nearer to the
spine than the left, the inclination of their origin
to the left being thus compensated, but to what-
ever extent this view may hold good, it is by no
means strictly correct ; in fact the length of the
arteries, whether comparative or absolute, is far
from regular; nor is the preponderance, when
present, always upon the same side ; the opinion
generally entertained is probably correct, the
right artery being in the majority of instances
somewhat longer than the left ; but the writer
has found the left the longer of the two, and
the same disposition has been observed by J. F.
Meckel; this is, however, an unusual disposition.
The relations of the arteries are simple.
During their descent they are situate in front of
the bodies of the lumbar vertebrae, with the
intervening fibro-cartilages, of one, two, or more
of these bones, according to the height at which
the arteries arise, and also of the lateral part of
the base of the sacrum ; they are both covered
upon three sides by the peritoneum, viz. in
front and laterally, the membrane descending
upon them from the root of the mesentery; the
mesentery itself also and the small intestines
are placed before them, and the latter overlap
them upon either side. Farther, they are in
front of the superior branches of the middle
sacral artery and of the sympathetic nerve.
That of the right side at its outset is placed
before the left primitive iliac vein, which it
crosses at its junction with the cava, and par-
tially before the commencement of the cava
itself; during its course it is in front of the
right primitive vein, at first only partially, but,
as it proceeds, covering it to a greater extent,
until at its termination it is directly before it.

External to both, but on a plane posterior to
them, are the psooe muscles, the left artery how-
ever being nearer to the muscle than the right,
between which and the psoas the right primitive
vein and the cava intervene, being at the same
time posterior to it.

Internal to both at their origin is the middle
sacral artery ; on the left side the left primitive
vein lies along the inside of the artery, but on a
plane behind it.

Anteriorly the arteries are crossed at their
termination by the corresponding ureter, that
duct being interposed between the peritoneum
and the vessel, but more adherent to the former.
The relation of the ureter to the iliac arteries is
not uniform, either on opposite sides or in
•different subjects ; the bifurcation of the pri-
mitive iliac may be assumed as the mean point
of reference for its transit, the duct descending
into the pelvis between the external and internal
iliacs, and before the internal ; but its precise
relation will depend upon the height at which
the bifurcation takes place and the side of the
body to which it belongs, and hence it very
frequently, if not usually, crosses the external
iliac upon the right and the termination of the
internal on the left.

The artery and vein, the relations of which
differ remarkably upon the two sides, the vein

being external upon the right and internal upon
the left, and upon both posterior, are enclosed
within a condensed cellular investment, pro-
longed upward upon the aorta and downward
upon the secondary iliacs; upon the primitive
vessels it is so thin that it may at times seem
absent; but, as it descends, it increases in
thickness, and acquires upon the external iliacs
considerable strength.

The primitive iliac arteries ordinarily give
only minute branches to the adjoining' parts,
viz. the ureter, the peritoneum, the vein, lym-
phatic glands and cellular structure ; but occa-
sionally they have been found to give off the
ilio-lumbar artery, and more rarely a renal or
spermatic artery.*

Although, accord ing to the view usually taken,
the primitive iliac terminates by dividing into
internal and external, yet in many instances it
will be found that the primitive and external
iliacs appear as one vessel giving off the internal
from its posterior side, and nearly at right
angles, while in the foetus the reverse seems the
case, the primitive and internal being continuous
and rather giving off the external.

INTERNAL ILIAC ARTERY.f (Arteria iliaca
internet, s. hypogastrica, s. umbilicalis; Fr.
artere iliaque interne, ou hypogastrique ; Germ.
Becken-pulsader oder innere Huft-pulsader.)
This artery from the time of birth' supplies the
viscera and parietes of the pelvis, both externally
and internally ; prior to that epoch it is the
channel through which the blood is trans-
mitted from the body of the fcetus to the
placenta, whence it may then be termed with
propriety the " placental artery," since such is
its chief office, the other distribution being of
inconsiderable extent, and the divisions of the
artery intended for it small in proportion;
hence the vessel presents a remarkable contrast
at the two periods of life, in the foetus being a
large and long vessel extending from the ter-
mination of the aorta, for, as has been before
stated, it seems at that time the continuation of
the primitive iliac artery, to the placenta giving
off in its course small branches to the viscera
and parietes of the pelvis, while in after life the
placental artery has disappeared, and in its
stead is found a short trunk of considerable
size, — the commencement of the placental
artery as it had been — from which arise nume-
rous vessels for the pelvis and its viscera.

The internal iliac arises from the posterior
side of the primitive iliac artery,]; between the
body of the last lumbar vertebra or the sacro-
vertebral angle, and the sacro-iliac articulation,
but generally higher upon the right side than
the left ; it descends into the pelvis in front of

* J. F. Meckel.

f The internal iliac and its branches should be
examined first with the pelvis complete, the peri-
toneum and viscera being detached from its lateral
wall, and the latter alternately empty and distended j
afterward a section of the pelvis may be made
through the symphysis pubis and the middle of the
sacrum, preserving the viscera with their attach-
ments to one side •, but this should not be done
until after the dissection of the perineum.

\ See primitive iliac for point and mode of
division.

ILIAC ARTERIES.

829

the sacro-iliac articulation or of the lateral part
of the sacrum, as it may be, inclining backward
and outward, and describing a curve concave
forward, until it reaches the superior part of the
great sciatic notch, where it usually divides ;
this however is by no means uniform, the point
of its division ranging between the brim of the
pelvis and the notch. The internal iliac is an
artery of great size, but in the adult smaller
than the external ; its course is somewhat tor-
tuous and short, from one and a half to two and
a half inches.

During its descent the artery is placed before
the lumbo-sacral nerve, on the left side before
the primitive iliac vein, and pn both before the
sacro-iliac articulation or the lateral part of the
sacrum. Before it are in the male the bladder
or its lateral connections, in the female the
uterus and its broad fold of peritoneum ; ex-
ternally the artery corresponds to the internal
iliac and the commencement of the primitive
iliac vems, to the inside of the psoas magnus
muscle, to the brim of the pelvis, to the obtu-
rator nerve, which it crosses nearly at right
angles, to the lumbo-sacral and first of the
anterior branches of the sacral nerves, and to
the superior attachment of the pyriformis
muscle : the ilio-lumbar artery is also external
to the internal iliac, between it and the wall of
the pelvis. Internal to it are the peritoneum,
the rectum with its mesentery, and the superior
hemorrhoidal vessels, (these parts being nearer
to the artery upon the left than the right,) and
the small intestine when in the pelvis.

The external iliac vessels are above, before,
and external to the internal.* In the foetus the
condition of the internal iliac differs remarkably
from that which it presents in after life ; in it
both in size and direction this artery appears the
continuation of the primitive trunk, exceeding
the external as much as afterward it is exceeded
by it. It is the channel which conveys the blood
to the placenta, and it is generally entitled the
" hypogastric or umbilical artery ;" " placental"
would certainly be preferable. It passes from
the primitive iliac or rather from the aorta, for
there the primitive iliac appears only the com-
mencement of the placental artery, downward
and at first outward as far as the sacro-iliac
articulation, where it gives off the external
iliac artery, then forward to the side of the
bladder, descending but little into the pelvis
and at the same time giving off pelvic branches;
it next changes its direction and ascends in-
clining inward toward the umbilicus, at first by
the side of the bladder and then in the anterior
abdominal wall, between the peritoneum and
the rectus muscle or its sheath, and on either
side of the urachus; thus forming a curve
convex downward through the concavity of
which pass the vas deferens or round ligament
before, the ureter posteriorly and the rectum,
the extremity of the ilium and the appendages
of the uterus in the mean space. Having reached
the umbilicus the artery escapes through it
from the body of the foetus and is conducted

* This is to be understood to refer to the recum-
bent posture ; in the erect posture the external are
not superior to the internal vessels.

by the umbilical cord to the placenta ; during
their transit to the placenta the arteries at the
very early periods of utero-gestation, are straight,
but afterwards, in proportion as the develope-
ment advances, they become tortuous, and are
twined round the umbilical placental vein,
whence the length of the arteries exceeds that
of the cord which varies from one to two feet.
At the placenta the two arteries are connected
by a considerable anastomosis, and divide into
numerous branches, which subdivide minutely
in the lobes of that structure, the ramifications
of the several lobes being distinct from each
other; ordinarily the two vessels are distinct
until they approach the placenta, but they have
been found to unite into a single one before
escaping from the abdomen of the foetus.*
The placental arteries give off within the body
of the foetus branches similar in number and
destination with those of the primitive iliac of
the adult, but in a rudimental condition ;
between the summit of the bladder and the
umbilicus however they do not furnish branches,
and hence, the circulation through them be-
tween these points ceasing at birth, they be-
come obliterated to the same extent and
connected into impervious cords, known by the
name of umbilical ligaments ; these hold the
same course and relation with the original
vessels, and are less distinct in proportion to
the age of the subject ; they are covered upon
their abdominal aspect by the peritoneum,
which is reflected upon them to a greater or
less extent according to the subject, and thereby
forms triangular falciform folds, the base of
which is below in the iliac fossa, and the apex
above toward the umbilicus, and in the free
edge of which the ligament is contained. At
a point intermediate to the brim of the pelvis
and the upper part of the sacro-sciatic notch the
internal iliac artery divides into branches ; these
are numerous, amounting altogether in the male
to nine, and in the female to eleven ; but in
their mode of origin they vary very much,
arising sometimes separately, sometimes by
common trunks, but for the most part from,
two, into which the iliac divides ; these are an
anterior one giving off the hemorrhoidal, the
umbilical, the vesical, the uterine, the vaginal,
the sciatic and internal pudic, and a posterior,
from which arise the ilio-lumbar, the lateral
sacral, the obturator and the gluteal. Another
diversity in the mode of their origin is that of
the obturator from the epigastric or external
iliac.

The branches of the internal iliac are arranged
either into four sets, viz. posterior, anterior,
internal, and inferior,f or into two, internal and
external,} the former distributed within, the
latter without the pelvis ; the latter seems the
more simple division, and is the one which will
be adopted in this article.

The internal branches are in the male five,
in the female seven ; they are as follow —

1 . The iliolumbar artery varies in size and ori-
gin ; for the most part it arises from the posterior

* Cloquet.
t Cloquet.
£ Harrison.

830

ILIAC ARTERIES.

division of the internal iliac, at times from the
iliac itself; at times from the gluteal, occa-
sionally from the primitive iliac, and frequently
by a trunk common to it and the lateral sacral ;
from its origin, which is somewhat below the
base of the sacrum, it runs upward, outward,
and backward toward the iliac fossa, passes in
front of the sacro-iliac articulation and the
lumbo-sacral nerve and external to the obturator
nerve; having surmounted the outlet of the
pelvis it passes behind the psoas muscle, the
external iliac vessels and the anterior crural
nerve, and emerges from behind them at the
superior and internal part of the fossa, where it
divides. As the artery emerges from the pelvis
it gives off a branch which descends along the
brim, gives small branches to the inside of the
psoas, and finally anastomoses with a branch
from the epigastric artery ; while concealed by
the psoas it gives branches to it and the iliacus
internus. Finally it divides into two sets of
branches, superior or ascending, and external or
transverse ; the former ascend beneath the
psoas, supply it, the iliacus and the quadratus
lumborum, send a branch into the vertebral
canal through one of the inferior intervertebral
foramina, and finally communicate with the
inferior lumbar arteries. The external set pass
outward into the iliac fossa, and are distin-
guished into two, a superficial and deep ; the
former run across the iliacus muscle, superficial
to it and beneath the iliac fascia, supply the
muscle and anastomose freely with corres-
ponding t branches from the circumflex branch
of the external iliac artery : the superior of the
superficial branches runs round the crest of the
ilium within its inner edge, as it proceeds it
gives branches downward to the iliacus and
upward to the quadratus lumborum, the trans-
versalis and oblique muscles, some of which
turn over the crest and communicate with
branches of the gluteal artery ; finally it ends in
a direct and free anastomosis with the ultimate
branch of the circuinflex artery, the fossa having
thus an artificial circle formed around it in-
ternally, between these branches and the original
iliacs. The branches of the deep set pass into
the substance of the iliacus muscle, and between
it and the bone, and are distributed to the
muscle, the periosteum, and the bone, one of
them entering the ilium through the canal to be
observed at the bottom of the fossa ; their deep
branches also communicate with the circumflex
iliac, the gluteal and the external circumflex
femoral arteries. Sometimes there are two
ilio-lumbar arteries.

2. The lateral sacral artery may be either
single or double, and arises either from the
posterior division of the iliac, from the iliac
itself on its inner side, from the gluteal, or the
sciatic, and frequently in common with the
ilio-lumbar : it runs downward, and inward in
front of the lateral part of the sacrum, the sacral
nerves at their exit from the anterior sacral
foramina, and the pyriform muscle external to
the middle sacral artery and the sympathetic
nerve ; it descends to the extremity of the
sacrum and then anastomoses with the middle
sacral and the artery of the other side ; at times

instead of terminating thus it enters the sacral
canal through the third or fourth foramen and
is distributed internally. Its branches are dis-
tinguished into two sets, an anterior or internal
and a posterior or external. The former are
distributed to the sacral nerves within the
pelvis, to the pyriform muscle, to the pelvic
cellular tissue and glands, to the levator ani
muscle and to the sacrum. The posterior are
the larger, they are usually four, but at times
more numerous, two branches sometimes taking
the same course; they pass backward along
the sacral nerves, through the sacral foramina,
into the canal, and then divide into two, of
which one is distributed within the canal to the
nerves and their ganglia, to the membranes and
the sacrum ; the other escapes backward
through the posterior sacral foramen, and is
distributed upon the back of the sacrum in the
sacro-vertebral channel, anastomosing with the
adjoining vessels.

3. The middle hemorrhoidal artery is some-
times wanting, its place being supplied by
branches from the other divisions of the iliac ;
it is of about the same size as the previous
arteries, and varies very much in its source,
arising from the anterior division of the iliac,
from that vessel itself or from the pudic, the
sciatic or lateral sacral arteries, it runs down-
ward, forward, and inward along the side and
front of the rectum, at first between the intes-
tine and the levator ani, and then between it
and the fund us of the bladder in man and the
vagina in the female, and divides into branches,
of which the greater part are distributed to the
rectum, anastomosing with the branches of the
superior hemorrhoidal from above and with
those of the inferior hemorrhoidal from below ;
others are distributed to the fundus of the
bladder, the prostate and vesiculae in man, and
to the vagina in the female.

4. The vesical arteries are subject to great
variety ; they are numerous and smaller than
the last described : they are distinguished by
Harrison into three sets, inferior, middle, and
superior ; the inferior set consists of those
branches given to the fundus of the bladder by
the middle hemorrhoidal, pudic, and sciatic
arteries; the superior, furnished by the um-
bilical, are two or more in number, and are
distributed to the superior region of the bladder,
but the middle is a single vessel larger than
the others, and given off by the iliac artery,
though frequently arising from some of its
branches, particularly the umbilical : it is en-
titled by Chaussier " vesico-prostatique :" it
passes downward and inward to the fundus of
the bladder, and then divides into branches
distributed to the bladder, and in the male also
to the prostate, the vesicular and neck of the
bladder.

5. The umbilical artery. In the adult sub-
ject a small arterial canal usually from an inch
and a half to two inches and a half long ex-
tends from the termination of the internal iliac,
or from one of its branches to the superior
lateral part of the bladder ; there it is continued
with, or seems to have attached to it superiorly
the umbilical ligament, the artery appearing

ILIAC ARTERIES.

831

rather to be continuous with the last branch
arising from it. A variable number of branches
arise from it ; these are generally the superior
vesical, at times the vaginal or the uterine ; and
according to their number and size its size
varies ; it is not destined to any part, but only
gives rise to these branches, being in reality not
a branch of the iliac but so much of the vessel,
originally the umbilical or placental, as inter-
venes between the origin of the great branches
and the point at which it becomes impervious,
which remains open because of the origin of
the vesical arteries, &c. from it, but is thus re-
duced in size because of their minuteness.

6. The uterine artery arises either from the
anterior division of the iliac, or from the pudic,
or at times from the umbilical ; it runs forward,
inward, and somewhat downward, until it
reaches the superior lateral part of the vagina,
and entering the broad peritoneal fold of the
uterus it ascends in it along the lateral region
of the uterus in a very tortuous manner, its
tortuosity increasing as it proceeds. As it as-
cends, it gives off a considerable number of
transverse branches, which attach themselves
to both surfaces of the organ, penetrate its
substance, and supply it with blood, anasto-
mosing, at the same time, freely with those
from the other side. When it has reached the
attachment of the ligament of the ovary, the
artery anastomoses with the spermatic artery.
Before the artery attaches itself to the uterus, it
gives a considerable branch to the vagina, which
descends along it to a greater or less extent
and is distributed to both its aspects. Branches
also go from it to the Fallopian tube, the round
ligament, and the ligament of the ovary, and
likewise communicate with branches of the
spermatic.

The uterine artery in the unimpregnated con-
dition of the uterus is a small vessel, little, if at
all, larger than the hemorrhoidal or vesical
arteries, but during impregnation, and the more
so in proportion as that state advances, it un-
dergoes a remarkable change, becoming greatly
enlarged, so much so as to equal or exceed in
size any of the other branches of the internal
iliac ; and at the same time assuming a most
tortuous arrangement as well in its branches as
in its trunk.

7. The vaginal artery arises also, when pre-
sent, from the anterior division of the iliac, or
from the pudic, the uterine, the umbilical, or
hemorrhoidal ; it is therefore very irregular and
often absent, its place being supplied by
branches from others. It runs forward and
downward along the side of the vagina, dis-
tributing branches to it, and also to the bladder
and rectum. At the extremity of the vagina it
terminates in the external genital organs, and
communicates with the branches of the pudic
artery.

The external branches of the internal iliac
artery are four, viz.

1 . The obturator or thyroid artery, (artere
sous-pubio-femorale, Chauss.) is a vessel of con-
siderable size, inferior only to the gluteal, pu-
dic, and sciatic branches, and about equal to
the epigastric artery, but irregular in that as

well as in other respects. It arises most fre-
quently from the posterior division of the
internal iliac or from the iliac itself imme-
diately before its division ; it runs forward and
somewhat downward along the lateral wall of
the pelvis toward the superior posterior part of
the subpubic or thyroid foramen, through
which it escapes from the pelvis into the supe-
rior internal part of the thigh. The course of
the vessel may be divided into three parts : —
1st, that within the pelvis ; 2d, that in the sub-
pubic canal ; 3d, that in the thigh. Within
the pelvis the artery is nearly parallel to the
brim of the pelvis, or ilio-pectineal line, and
from one-half to three-fourths of an inch be-
neath it, it holds a similar relation to the exter-
nal iliac vessels, which are above the line and
from which it is distant from three-fourths of an
inch to one and one-fourth. It is accompanied
by the obturator vein and nerve, and is placed
between them, the nerve being above and the
vein beneath it. It is situate within the pelvic
fascia; externally it rests against this fascia
above the origin of the levator ani muscle, and
separated by it from the internal obturator
muscle ; internally it corresponds in front to
the side of the bladder to an extent proportioned
to the degree to which that viscus may be dis-
tended, and is connected to it by cellular sub-
stance ; posteriorly it corresponds to the peri-
toneum of the pelvis, the ureter, and at times
to the anterior division of the iliac artery or
some of its other branches. In this part of its
course it gives off a branch which ascends to
the iliacus and psoas, branches to the obtura-
tor internus, to the lymphatic glands of the
pelvis and the bladder ; lastly, as it approaches
the subpubic foramen it gives an important
branch, which ascends posterior to the pubis,
distributes small branches as it proceeds, and
ends in an anastomosis with a branch, which
descends from the epigastric artery. Harrison
has occasionally found a considerable branch
given off in this situation, which passed to the
side of the prostate and the perineum, supply-
ing the place of deficient branches of the pudic
artery.

In escaping from the pelvis the artery is
contained in an oblique canal leading inward
and forward. This canal, the subpubic, is
bounded superiorly and externally by the pu-
bis, which presents on the under surface of its
horizontal ram us an oblique channel, by which
the roof of the canal is formed ; inferiorly and
internally it is bounded by the margins of the
obturator muscles and ligament; toward the
pelvis it presents a defined aperture circum-
scribed above by the pubis and below by the
pelvic fascia, the attachment of which to the
bone is interrupted at the part at which the
artery passes out, and which describing a
curve beneath the vessels, between its points
of attachment at either side contributes thus to
form a rounded aperture through which they
escape without perforating the fascia; a thin
prolongation of the fascia is detached from it
beneath the vessels into the canal. Hernia
occasionally protrudes through this canal, and
the artery has been found by Cooper behind

832

ILIAC ARTERIES.

•the neck of the sac and rather to its inner side.
While within the canal the artery gives outward
a considerable branch — its posterior or exter-
nal, or it might be with propriety called its
thyroid branch — which runs downward and
backward along the external margin of the
thyroid foramen, between the two obturator
muscles, giving them branches, and at times
altogether consumed in them. Having reached
the tuberosity of the ischium, it gives branches
to the quadratus and adductor magnus muscles,
to the upper attachments of the flexors of the
leg, and to the ilio-femoral articulation, into
which it sometimes sends through the cotyloid
notch a branch more frequently supplied by
the internal circumflex (femoral) artery ; it also
sends another round the thyroid foramen,
which meets a similar branch from the obtura-
tor. It anastomoses with the internal circum-
flex and the sciatic arteries. At its entrance
into the thigh, the obturator artery is situate
above and before the obturator externus muscle,
and behind the pectinalis, which with some of
the fibres of the adductor longus must be divided
in order to expose the vessel. It descends be-
tween the pectinalis, the long and short adduc-
tors, and is distributed to them, the adductor
magnus, the gracilis, and the integuments upon
the upper and inner part of the thigh. It gives
also a branch, which runs round the margin
•of the thyroid foramen, and meets the branch
already described from its thyroid branch. The
artery anastomoses freely with the internal cir-
cumflex artery.

The obturator artery presents many varieties
as to its source, of which some are deserving
<of particular attention. According to J. F.
Meckel its ordinary source is the posterior
division of the internal iliac, either immediately
or by a trunk common to it and the ilio-lumbar,
but at least once in ten times it arises from another
source. The next most frequent is the internal
iliac itself above and before its division ; then
the anterior division of the iliac ; occasionally
the external iliac, and sometimes the femoral,
even so low as two inches from Poupart's liga-
ment. The most frequent variety, and which
according to the same authority is as common
as the origin from the internal iliac itself, is
that the artery arises from the epigastric, or from
a trunk common to both. Sometimes it has a
double origin, being formed by the union of
two branches of equal size, one from the epi-
gastric, and the other from the internal iliac,
and at times it has a different source upon op-
posite sides. In every case the destination of
the artery is the same; it runs to the inner
aperture of the subpubic canal, in order to
escape to the thigh, and in so doing it holds a
very intimate relation to the internal femoral
ring in those instances in which it proceeds
either from the epigastric or from the femoral.
When it arises from the epigastric, it runs
obliquely downward, backward, and inward,
above the crural arch, toward the superior
aperture of the pelvis, then entering the pelvis
posterior to the pubis it turns downward be-
neath it, and gains the subpubic foramen.
During its descent into the pelvis the artery

superiorly is covered by the peritoneum, and
interiorly corresponds to Poupart's ligament
and the internal femoral ring, but the side of
the ring, at which it may be placed, varies in
different instances. When the common trunk
from which the epigastric and obturator arise is
short, the obturator lies close to the inside of
the external iliac vein and then is situate on
the outer side of the ring, while when the com-
mon trunk is long the artery is more remote
from the vein, coasts along the base of Gimber-
nat's ligament, and thus runs obliquely across
the front and inner side of the aperture. Ac-
cording to the case, therefore, will be the rela-
tion of the artery to the neck of femoral hernia ;
in the former it will be situate external and
posterior to it, in the latter anterior and inter-
nal.

When hernia descends not only into the lym-
phatic compartment of the sheath, but, as has
been observed by Burns, also into that belong-
ing to the vein, thus forming a double protru-
sion, the artery may, if the common trunk be
short, be situate external to the neck of the
former and internal to that of the latter.

The comparative frequency of this mode of
origin of the obturator artery has been diffe-
rently estimated. According to Monro it oc-
curs in one of twenty cases ; Velpeau coincides
in this opinion; Lawrence states it to be once in
ten ; J. F. Meckel considers it to be as frequent
as that from the internal iliac; and according
to the observations of Cloquet the proportion
of instances in 250 subjects in which the artery
was found to arise from the epigastric, whether
on one or both sides, was one in three, and that
of all the origins from the epigastric to all
those from other sources was still greater, about
1.2g. A more important question is the pro-
portion borne by those instances in which the
obturator arising from the epigastric is situate
on the inside of the neck of the hernia, to the
total number of such cases, or to that of cases
of femoral hernia requiring operation, for it is
obviously with it that the operator is concerned.
Cooper has not met the artery on the inside of
the hernia, though in six of twenty-one cases
he found the origin from the epigastric ; and
Lawrence states that the proportion of the for-
mer cases does not exceed one in eight or ten,
and therefore that the obturator artery would
be endangered only once in eighty or one hun-
dred operations.

When the obturator arises from the femoral
artery, which Cloquet found in six of 250
subjects, it ascends into the abdomen beneath
the crural arch, along the pectinalis muscle and
internal to the femoral vein, and in femoral
hernia is found behind the sac.

We are indebted to J. F. Meckei for solving
the apparent irregularity of these origins of the
obturator, and reducing them to a mere varia-
tion of the normal condition ; the obturator, as
has been stated, is normally connected with the
epigastric by an anastomotic branch, and hence
may be considered as having two origins, an
anterior and a posterior, a disposition the reality
of which is more manifest at the earlier periods
of life, and according as the one or the other

ILIAC ARTERIES.

833

may be deficient or more developed, the obtu-
rator will be derived principally or altogether
from the internal iliac or from the epigastric ;
when both are equally so it will present the
double origin.

2. The glutted artery, denominated also
posterior iliac, is the largest branch of the
internal iliac, and arises from, or is the conti-
nuation of the posterior division of that vessel ;
it runs downward, back ward, and outward, until
it reaches the superior part of the great sciatic
notch ; it then changes the direction of its
course, and making a turn passes directly out-
ward between the lumbo-sacral and the anterior
branch of the first sacral nerves, and escapes
from the pelvis through the upper part of the
notch above the pyriformis muscle, and accom-
panied by the superior gluteal nerve. As soon
as the artery has escaped from within the pelvis
and gained its external aspect, it divides into
branches. The trunk of this artery, as it is the
largest, so is it the shortest of the branches of
the iliac; within the pelvis it corresponds ex-
ternally to the lumbo-sacral nerve, internally to
the rectum, and inferiorly to the first sacral
nerve and the pyriformis ; it gives small
branches to the rectum, the pyriformis, and the
surrounding cellular structure ; at times it also
gives off the ilio-lumbar, the lateral sacral, or
the obturator.

At its exit posteriorly from the pelvis it is
situate between the adjoining margins of the
pyriformis and the glutens minimus, and it is
covered by the gluteus maximus.

The branches into which it divides after its
escape are two, a superficial and deep one.
The first passes outward and upward between
the glutei maximus and medms, and divides
into numerous branches, which are distributed
to these muscles, particularly to the maximus ;
many of them descend in its substance toward
its insertion, and there meet branches of the
circumflex (femoral) and sciatic arteries; others
pass through the muscle, become superficial,
and supply the integument and subcutaneous
fat; others again pass onward, traverse the
attachment of the gluteus maximus to the sa-
crum, and are distributed to the muscles and
integuments of the posterior sacral region.

The second, the deep branch, passes outward,
upward, and forward, between the glutei medius
and minimus muscles toward the superior
anterior spinous process of the ilium in an
arched course around the attachment of the
gluteus minimus. As it proceeds it gives off
numerous branches upward from its convexity
and downward from its concavity ; the former
are distributed to the gluteus medius; the lat-
ter are chiefly two, of which one runs forward
and downward toward the anterior part of the
great trochanter between the two muscles, gives
branches to both, and finally throws itself into
the gluteus medius near the tyochanter, and is
consumed in it : it communicates freely with
the external circumflex artery. The other runs
downward and forward toward the back of the
trochanter, lies for some way upon the eluteus
minimus, or over the interval between ~it and
the pyriformis, gives branches to both muscles,

VOL. ir.

and then gains the surface of the os innomina-
tum by traversing the gluteus or by passing
between it and the pyriformis, pursues its course
upon the bone, to which it gives an artery, above
the ilio-femoral articulation, to the capsule of
which it also gives branches, and approaching
the anterior inferior spinous process of the ilium
it terminates in supplying the gluteus minimus,
and anastomosing with the external circumflex
artery.

The deep division of the gluteal artery hav-
ing run round the line of attachment of the
gluteus minimus, and reached the superior
anterior spinous process, terminates in an anas-
tomosis with the circumflex iliac, the ilio-lumbar,
and the external circumflex arteries; branches
also turn over the crest of the ilium, and so
communicate with the iliolumbar. The deep
division, also, furnishes a nutritious artery to
the ilium, the canal for which is to be seen on
the dorsum of the bone. The branches of the
gluteal artery are numerous and large ; in order
to expose them the gluteus maximus having
been dissected clean may be detached from the
femur and raised toward the sacrum, when the
branches may be displayed running in every
direction as from an axis.

The situation of the gluteal artery external to
the pelvis permits the trunk of the vessel to be
secured ; the gluteus maximus being the only
muscle by which it is covered, it may be exposed
by the division of that muscle; the situation of
the artery may be first determined " by drawing
a line from the posterior spinous process of the
ilium to the midspace between the tuberosity of
the ischiumand the great trochanter; if we divide
this line into three, we shall find the gluteal
artery emerging from the pelvis at the juncture
of its upper and middle thirds." * The ligature
of this artery in case of aneurism has been very
much superseded in favour of that of the inter-
nal or even of the primitive iliac, the latter of
which has been tied by Guthrie for aneurism
of the gluteal artery ; the propriety of this pro-
ceeding, however, may be questioned; the
ligature of either the internal or the primitive
iliac must be regarded a more serious operation
than that of the gluteal, and the latter has
proved so efficacious in the many instances in
which it has been had recourse to, that, while
it is practicable, the other can be hardly justi-
fiable.

3. The ischiatic artery arises from the ante-
rior division of the internal iliac, which, after
having given off its internal branches, divides
into two, of which the posterior and larger is
the ischiatic; it is the second in size of the
branches of the iliac, being smaller than the
gluteal; but in the adult it appears, for the
most part, in direction the continuation of the
original vessel ; its course within the pelvis is
long; it descends, at the same time inclining
forward, and forming a curve convex backward,
toward the inferior part of the great sciatic
notch, and escapes through it from the pelvis
superior to the sacro-sciatic ligaments and infe-
rior to the pyriformis muscle; it then descends

Harrison.

3 I

834

ILIAC ARTERIES.

behind the ischium between its tuberosity and
the great trochanter of the femur, and gives off
as it descends numerous branches distributed
in the superior posterior region of the thigh.
Within the pelvis the artery is situate internal
to the sacral nerves and the pyriformis muscle,
external to the rectum and the peritoneum, in
front of the sacrum, the nerves and the attach-
ments of the pyriformis, and posterior and ex-
ternal to the pudic artery; in escaping from the
cavity it passes between the pyriformis and
ischio-coccygeus muscles, and is accompanied
by the pudic artery, to which it holds the same
relation as before, but is closer to it, and by the
sciatic nerve; within the pelvis it is internal
and anterior to the sacral plexus, but as it goes
out it passes between its branches, and thus
becomes posterior to the nerve.

Without the pelvis the ischiatic artery corre-
sponds in front to the spinous process of the
ischium, the gemelli, with the obturator inter-
nus muscles, and the quadratus ; posteriorly, it
is covered by the gluteus maximus and the inte-
guments ; it is situate at first behind the sciatic
nerve, but as it descends it becomes internal to
the nerve, the distance between them increasing
at the same time. While behind the spinous
process of the ischium the ischiatic artery is
external to the pudic artery, and more super-
ficial, i.e. still posterior; but as the pudic passes
to the inside of the tuberosity of the bone, while
the ischiatic runs on its outside, the two vessels
immediately separate and cease to be related.

Within the pelvis the ischiatic artery gives
some irregular and small branches to the rec-
tum, the bladder, the uterus, the vagina, the
cellular tissue, the pyriformis and levator mus-
cles ; at times it is considered as giving off
also the pudic, the hemorrhoidal, or obturator
arteries. The branches which it furnishes ex-
ternal to the pelvis are numerous ; among them
are distinguished the following : — 1. Thecoccy-
gean branch, of considerable size, runs down-
ward and inward toward the coccyx, across the
pudic artery and posterior to it, passes through
the great sacro-sciatic ligament, and divides into
branches, which are distributed to the ligament,
to the gluteus, the coccygeus, and levator ani
muscles, to the posterior aspect of the sacrum
and coccyx, and to the fat and integument ; its
branches communicate with those of the pudic.
2. A considerable branch or set of branches,
which run outward and downward toward the
back of the great trochanter upon the internal
obturator, gemelli, and quadratus muscles, sup-
ply them with branches, and anastomose with
the circumflex (femoral) arteries. 3. A branch
or branches to the inferior part of the gluteus
maximus, prolonged through it to its insertion,
and then meeting the circumflex and perforating
arteries. 4. A branch or branches, which
attach themselves to the sciatic nerve, naturally
of small size, but regular, and remarkable for
the extraordinary change they undergo after the
interruption of the main artery of the thigh;
they arise about the tuberosity of the ischium,
and descend along the nerve giving it branches,
and communicating with branches from the
perforating arteries, which also attach them-

selves to the nerve, whereby a chain of anasto-
moses is established along it, which, when the
main channel has been interrupted, becomes
amazingly enlarged and forms, as it were, one
remarkably tortuous vessel along the entire
length of the nerve. 5. A very considerable
branch, the termination of the artery, distri-
buted to the upper extremity of the flexors of
the leg, the biceps, &c. and of the adductor
muscles ; the ramifications of which communi-
cate with the perforating and internal circumflex
arteries.

The ischiatic artery is circumstanced external
to the pelvis so similarly to the gluteal, that, if
necessary, it might be exposed during life by a
similar operation ; for a method of determining
its situation prior to operation, the reader is re-
ferred to the description of the pudic artery.

4. The internal pudic artery arises from the
anterior division of the internal iliac, which for
the most part, after having given off its other
branches, divides into the ischiatic and the
pudic ; the height at which the division takes
place is uncertain ; at times it does not occur
until the trunk has descended to the sciatic
notch, or even escaped from the pelvis. The
pudic artery is smaller than the sciatic; it
passes downward, forward, and inward, until it
reaches the inferior part of the great sciatic
notch, through which it escapes from within
the pelvis in company with the ischiatic artery,
the pudic, and sciatic nerves ; having escaped
from the pelvis it crosses the extremity of the
spinous process of the ischium and the attach-
ment of the anterior sacro-sciatic ligament, and
returns into the cavity through the anterior
notch, accompanied by the pudic nerve ; having
re-entered the pelvis, it then runs forward, in-
ward, and downward internal to the tuberosity
of the ischium, until it reaches its anterior ex-
tremity, whence it continues its course upward
along the inside of the rami of the ischium and
pubis toward the arch of the pubis, and beneath
the latter finally divides ; the course of the
artery, therefore, forms a considerable curve
convex downward and backward, during which
the vessel is contained within the pelvis at its
commencement and its termination, and is
without the cavity during the intermediate part.
Its course is thence divided into three stages,
during two of which it is within, and in the
third without the cavity.

The first stage of the artery's course, through-
out which it is contained in the pelvis, extends
from its origin to the lower part of the posterior
sacro-sciatic notch, through which it escapes
from the cavity ; it is of variable length, in con-
sequence of the variable height at which the
vessel arises. The relations of the artery during
this stage are posteriorly and externally the
sacral nerves, the pyriform muscle, and the
sacrum ; internally the peritoneum and the
rectum ; it is posterior and external to the fun-
dus of the bladder and the vesiculae seminales,
and anterior and internal to the ischiatic artery;
previous to its exit it sometimes passes between
the sacral nerves before forming the plexus.
It goes out from the pelvis below the pyriformis
and above the spinous process of the ischium

ILIAC ARTERIES.

835

and the anterior sacro-sciatic ligament, passing
between the pyriformis and the ischio-coccygeus
muscles, and having the ischiatic artery and
sciatic nerve both external and posterior - to it.
Its second stage is situate without the pelvis ;
it is usually its shortest one, lasting only while
the artery is crossing the extremity of the
spinous process of the ischium, and not exceed-
ing an inch in length ; it is here situate behind
and above the spinous process and the anterior
or lesser sciatic ligament ; it is covered poste-
riorly by the superior edge of the posterior liga-
ment and by the glutens maximus muscle ; it
is internal to both the ischiatic artery and
sciatic nerve, and it is crossed posteriorly by
the coccygean branch of the former.

The third stage of the artery is its longest
and most important one ; during it the vessel
is situate within the skeleton of the pelvis,
though not within the pelvis, in the ordinary
sense of the phrase, i. e. within its visceral ca-
vity, being excluded therefrom by the struc-
tures which form its floor; it lies along the
inside of the tuberosity of the ischium and the
rami of the ischium and pubis, and its course and
relations being different at the posterior and an-
terior parts of the stage, they may with advan-
tage be considered separately. In the posterior
part, or as far forward as the anterior extremity
of the tuberosity or the base of the triangular
ligament of the perinaeum, the artery descends ;
in the anterior it ascends ; in the posterior it is
situate in the outer wall of the space which in-
tervenes between the inside of the tuberosity of
the ischium and the rectum — the ischio-rectal
space. This space is cuneiform, its base below,
toward the surface ; its apex above, toward the
pelvis ; its inner wall is formed by the levator ani
and the dense thin expansion by which the mus-
cle is covered externally or interiorly, its outer
by the obturator fascia attached inferiorly to the
edge of the great sacro-sciatic ligament and of its
falciform process, and by the obturator muscle :
the space is occupied by,a mass of adipose cel-
lular structure, traversed by some branches of
the pudic vessels and nerves. In a canal in
the obturator fascia the artery is contained
through the posterior part of the third stage ; by
some it is maintained to be between the fascia
and the muscle, in a sort of canal formed inter-
nally by the fascia, externally by the muscle
and tuberosity, and inferiorly by the great
sciatic ligament ; but this is not correct ; the
vessel being in the fascia, and not external to
it ; the line of its course is convex downward,
about an inch and a half from the under surface
of the tuberosity of the ischium at its most de-
pending part, and from two to two and a half
inches from the surface, this distance varying of
course according to the condition of the sub-
ject ; the line approaches the margin of the
ramus or the spinous process, thence forward
or backward. In the anterior part of the stage
the vessel is enclosed in the triangular ligament
along its attachment to the bone; consequently,
it is separated from the surface by the superfi-
cial stratum of this structure first, in the second
place by the cms penis, covered by the ischio-
caveruous muscle, and behind it by the trans-

versus perinei muscle ; and lastly, by the super-
ficial structures of the perineum. As the artery
proceeds it becomes more superficial, and finally
emerges from the triangular ligament, beneath
the subpubic ligament, as the dorsal artery of
the penis.

It is in its third stage that the pudic artery
is exposed to danger in the lateral operation of
lithotomy ; it may be wounded in either of the
two steps of dividing the urethra and prostate
or the subsequent division of the superficial
structures: in the former case, the danger of
the accident will be greatest when the section is
effected with the scalpel or gorget, and in pro-
portion to the width of the blade, and the de-
gree to which the cutting edge may be directed
outward, will the danger be enhanced ; in the
second, the risk will be alike with all cutting
instruments, and will be determined by the
width of the blade, the attention paid to a pro-
per degree of lateralization, the manner in
which the instrument is made to effect a divi-
sion of the parts, and the extent of the section.
The branches of the pudic artery are numerous,
and may be conveniently arranged according to
the stage of its course, in which they are given
off. In its first, before its exit from the pelvis,
it gives branches to the bladder, the rectum,
the vesiculae, prostate, vagina, and uterus ; it
also frequently furnishes the middle hemor-
rhoidal.

In its second stage, while external to the
pelvis, it gives branches to the glutens, the pyri-
formis, the obturator and gemelli muscles, the
sacro-sciatic ligament, the ischium, and sacrum ;
they anastomose with the ischiatic, the gluteal,
and internal circumflex arteries.

Those which arise in its third stage are the
most important. 1. The artery gives, while on
the inside of the tuberosity of the ischium,
branches which are distinguished into external
and internal ; the former are small, and go to
the adipose structure beneath the tuberosity, to
the attachment of the biceps, to the obturator
internus, and the integuments : the internal are
larger ; they come through the obturator fascia,
run inward toward the anus, and are distributed
to the adipose cellular structure of the ischio-
rectal space, to the levator and sphincter ani, to
the extremity of the rectum, and the margin of
the anus; they anastomose with branches of
the middle hemorrhoidal artery and with those
of the other side : they are variable in number,
being one, two, or three, and are denominated
" external hemorrhoidal ;" they are liable to be
divided in operations in the vicinity of the
anus, e. g. in the superficial incision in the
lateral operation or in operation for fistula;
they are, however, so small that they seldom
give trouble, either ceasing to bleed spontane-
ously, or being commanded by brief compres-
sion.

2. The perineal artery. — At a short distance
from the base of the triangular ligament the
pudic gives off a branch of considerable size
and length, by many regarded as one of its
ultimate branches ; the pudic, according to
them, terminating by dividing into two branches,
an inferior, " the perineal," and a superior.
3 i 2

ILIAC ARTERIES.

The perineal artery comes through the obtu-
rator fascia, and descends to the perineum, pos-
terior to the transverse muscle, though at times
before it; when it has got below the muscle it
changes its direction, and runs forward, up-
ward, and inward, superficial to the triangular
ligament, toward the root of the scrotum; at
this part of its course it is situate along the
outer side of the interval which separates the
crus penis and the corpus spongiosum urethrse,
internal and parallel to the crus, and covered
by a superficial lamina of the fascia of the peri-
neum, a deeper layer of which intervenes be-
tween it and the muscles of the crus and bulb
and the triangular ligament ; as it proceeds it
gives the following branches : 1 . outward, one
to the integument and subcutaneous structure
beneath the anterior part of the tuberosity of
the ischium ; 2. inward, one which runs to the
interval between the front of the rectum and
the bulb of the corpus spongiosum, superficial
and parallel to the transverse muscle ; it sup-
plies the integument and subcutaneous struc-
ture of the perineum, and the common inser-
tion of the superficial sphincter, the transverse
muscle, the bulbo-cavernous and the levator ani
in front of the rectum. This branch is at times
furnished by the pudic itself; it is denominated
by some " the proper perineal," by others " the
transverse perineal." 3. A branch to the bulbo-
cavernous ; 4. one to the ischio-cavernous mus-
cles.

The perineal artery having reached the back
of the scrotum sends long branches into the
subcutaneous structure and integument of that
part, and entering the septum scroti, terminates
in it as the " artery of the septum." In the
female, the ultimate branches of the artery are
distributed to the labia majora.

The perineal artery, from its superficial situa-
tion, is exposed to be divided on many occa-
sions ; in lateral lithotomy it may be cut, but
for the most part it escapes, its course being
external to the line of incision ; some of its
branches, however, cannot escape, the trans-
verse perineal particularly must, as a matter of
course, be divided. Having given off the peri-
neal artery, the pudic pursues its course, en-
closed in the triangular ligament, along the
rarni of the ischium and pubis, toward the arch
of the pubis ; arrived under cover of the crus
penis, it gives off a considerable branch, des-
tined principally for the urethra and the corpus
spongiosum, and denominated hence by Chaus-
sier " urethro-bulbaire," by Harrison " arteria
corporis bulbosi vel spongiosi urethra," but by
Boyer and Cloquet " artere transverse ;" it is
short, runs transversely inward, enclosed in the
triangular ligament about a quarter of an inch
from its base, but nearer to it externally than
internally; at the bulb it divides into two
parts, of which one, the smaller, is distributed
to the ante-prostatic gland ; the other enters the
bulb and ramifies through its vascular struc-
ture, being prolonged through it as far as the
glans, supplying at the same time the mem-
brane of the urethra and its lacunae ; a branch
from it passes into the corpus cavernosum, and
anastomoses with the artery of that structure.

In the female, the branch corresponding to this
is distributed to the vascular plexus which sur-
rounds the orifice of the vagina.

The artery of the bulb is one of much prac-
tical importance ; it is liable to be wounded in
lithotomy in the act of opening the urethra;
this accident is incurred when the canal is
opened too high, i. e. too near to the arch of
the pubis, or too much from the side rather
than from beneath, and in either case is pretty
certain to occur ; the proceeding by which to
avoid both the artery and the bulb itself, is to
cut into the urethra as far back, i. e. from the
surface, and as far from the arch as the gui-
dance of the staff will assure the operator to be
safe, the point of the knife being directed as
much from below as the interference of the
bulb and the lateral line of incision will permit;
further, it is the design of the operator to open
the canal in the membranous portion and be-
hind the bulb; and in order to effect this, the
incision should be made as near as may be to
the base of the triangular ligament, or, if possi-
ble, behind it. If divided, the artery of the
bulb may be tied, though not without some
difficulty ; it is prevented from retracting by
being enclosed in the triangular ligament, but
it is situate deep ; its distance from the anterior
surface of the ramus of the pubis being about
three-fourths of an inch ; its shortness as well
as its being concealed by the crus penis and
by the bulb with their muscles, and being in
the superior angle of the wound, must also
increase the difficulty of securing it.

The pudic artery having reached the base of
the subpubic ligament divides into its two
final branches, the artery of the corpus caverno-
sum and the dorsal artery of the penis.

3. The artery of the corpus cavernosum arises
from the pudic between the cms penis and the
ramus of the pubis and immediately enters the
crus obliquely ; it is prolonged through the
vascular tissue of the corpus cavernosum to its
extremity, distributing branches to either side,
and communicating with that of the other.
For the peculiar distribution ,of the arteries of
the corpus cavernosum and spongiosum, accord-
ing to Muller, see the article ERECTILE TISSUE.

4. The dorsal artery of thepenis, which ap-
pears in direction the continuation of the original
vessel, comes through the triangular ligament
and ascends in front of the subpubic ligament
through the angle formed by the crura penis at
their junction ; having surmounted the crus it
attaches itself to the dorsal aspect of the penis
and runs forward upon it on either side of the
suspensory ligament parallel to the artery of
the other side, and contained together with it,
the dorsal vein, and nerves, in the groove
formed by the apposition of the crura, internal
to the nerve and external to the vein; it is
prolonged to the anterior extremity of the
corpus cavernosum, where it breaks up into
branches, which uniting with those of the other
form an arterial zone behind the corona glandis,
and sinking into the glans are distributed to its
tissue.

During their course along the dorsuin of the
penis the arteries are tortuous, communicate

ILIAC ARTERIES.

837

frequently, are covered not only by the skin
and subcutaneous cellular structure, but also
by a dense filamentary expansion, or fascia,
which invests the penis beneath them, and they
give branches to those structures as also to the
fibrous membrane of the corpus cavernosum,
and finally to the prepuce. The dorsal artery
is at times furnished by the obturator, or the
external pudic artery.

Beside the varieties of origin which have
been mentioned, the pudic presents some im-
portant varieties in its course. It has been
found by Burns in four instances, "instead
of passing out of the pelvis between the
sacro-sciatic ligaments to attach itself to the
lateral and inferior part of the bladder, and to
traverse the upper segment of the prostate
gland in its course to the ramus of theischium."
Another variety is described by Harrison, in
which the proper trunk of the pudic is found
unusually small, and the dorsal artery of the
penis arises originally and separately from the
internal iliac, runs along the side of the bladder
and prostate gland, and escapes from the
pelvis along with the dorsal vein of the penis
beneath the arch of the pubis. The latter dis-
position, mutatis mutandis, has been found by
Tiedemann in the female as well as in the
male, and is figured in his thirtieth plate. It is
described by Wmslow as the normal arrange-
ment, only thataccording to him the vessel, which
takes this unusual course, arises sometimes
from the common pudic, at others from the
iliac. Haller questions the occurrence of this
disposition, but describes another, in which
the inferior vesical artery arising from the
middle hemorrhoidal is" continued on the
dorsum of the prostate into the dorsal artery of
the penis, given, as in ordinary, from the pudic.

Among the varieties of the arterial system
few possess greater interest than these, inas-
much as no foresight or skill can guard against
the untoward accidents which attend their
presence in lithotomy ; their possibility forbids
a section of the prostate upward; but for-
tunately they are rare.

The situation of the pudic artery upon the
exterior of the pelvis admits the possibility of
tying the vessel in the living subject; the
plan of operation necessary for the purpose
is similar to that to be adopted with the gluteal
artery, only it must be performed lower down ;
it is the same with that for the ischiatic artery ;
for determining the situation of which or the
pudic the following directions are given by
Harrison :* — " Place the individual on his face
with the lower extremity extended and the toes
turned inwards : feel for the summit of the
great trochanter, and for the base or articulated
end of the coccyx ; these two points are on a
level ; then draw a line from one to the other,
and we may be certain that the pudic artery
and the spine of the ischium are opposite the
junction of the middle and internal thirds of
this line." The ischiatic artery may be
reached as easily, or even more so, than the

* Vol. ii. p. 103.

gluteal ; but the difficulty which must attend
the seeking for the pudic must be extreme.

THE EXTERNAL ILIAC ARTERY, (arterid
iliaca externa, Lat. ; artcre iliaque externe,
Fr. ; portion iliaque de la crurale, Chauss. ;
Aussere Huft-pulsader, Ger.) is the vessel
destined for the supply of the lower extremity,
of which the portion contained within the
abdomen, in the iliac region, is denominated the
" external " iliac, in contradistinction to the
artery of the pelvis, the " internal."

It commences at the division of the primi-
tive iliac artery, at a point intermediate to the
body of the last lumbar vertebra, or the sacro-
vertebral prominence, and the sacro-iliac articu-
lation, and it terminates at the crural arch, at
a point midway between the superior anterior
spinous process of the ilium and the spinous
process of the pubis,* or at the outer side of
the ilio-pectineal eminence of the os innomina-
tum. The point at which the vessel com-
mences is not uniform either in all subjects or
on the two sides of the same; depending upon
the point at which the primitive iliac divides,
which is variable, it will be higher or lower,
nearer to the vertebra or to the articulation,
according to the situation of the bifurcation of
that vessel : on the right side of the body the
artery commences for the most part nearer to
the body of the vertebra than on the left, on
which it is of course nearer to the articulation ;
hence the artery arising higher upon the former
is longer upon that side than upon the latter,
the difference in length varying from a quarter
to half an inch. The external iliac terminates
in the femoral or crural artery, strictly so
called ; but the distinction between the two is
one only of convenience, inasmuch as they are
but different stages of the same vessel ; there
appears therefore much propriety in the

* The situation of the artery at its termination is
differently stated by different writers ; Boyer states
it to be midway between the spinous process of the
ilium and the symphysis pubis ; Cloquet, midway
between the spine of the ilium and the spinous pro-
cess of the pubis ; Harrison, about half an inch to
the pubic side of the centre of the crural arch. The
relation of the vessel to the points between which
it is placed, is probably not the same in all cases ;
but that assigned to it by Cloquet seems most
generally applicable. According to Cooper, with
whom Cloquet concurs, there are, in the male,
3£ inches from the symphysis pubis to the
middle of the artery, and in the female 3|,
while the distance to the superior anterior spinous
process of the ilium is in the former 53., and in
the latter six inches ; the artery must therefore be
external to the mid-point, being for the most part
concave forward and inward above, and convex
forward below ; but in this particular it is not uni-
form, being sometimes nearly straight ; the degree
of its tortuosity also appears to depend upon the
age of the subject and the plenitude of the vessel.
The direction of the artery is oblique, and as the
primitive iliac and it are continuous in the adult, the
course of both the vessels maybe defined, during
life, by a line extending from the umbilicus, or
from half an inch below it, at its left side, to a point
midway between the superior anterior spinous pro-
cess of the ilium and the spinous process of the
pnbis, the upper extremity of the line varying
according to the situation at which the aorta divides.

838

ILIAC ARTERIES.

designation adopted by Chaussier, which,
while it recognises the identity of the vessel
throughout its course, sufficiently marks the
grounds of distinction between its two portions.
The external is somewhat smaller than the
primitive iliac, but in the adult considerably
larger than the internal ; its direction is down-
ward, outward, and forward, and hence it
forms with the primitive iliac a curve convex
backward, and seems the continuation of that
vessel; its length is from three to four inches,
and during its course it forms one or more
curvatures.

Such is the disposition of the vessel in the
adult ; but in the younger subject it is different
in some respects ; in the foetus the external iliac
is considerably smaller than the internal, and
does not seem the continuation of the primitive
iliac, which at that epoch is continued into the
internal; the external appearing rather as a
branch or a smaller division from a trunk
common to the other two : after birth the
relative disposition of the iliacs gradually
changes, until they acquire that of the adult.

The relations of the external iliac artery are
as follows : posteriorly, it corresponds through
the upper half of its course to the lateral part
of the superior aperture of the pelvis; inclining
outwards as it descends, it corresponds in its
lower half to the os innominatum, and the more
perfectly, the nearer it approaches the crural
arch, at which part it is placed in front of the
bone, crossing it nearly at right angles, and
separated from it by an interval occupied by
thepsoo-iliacaponeurosis and the psoas muscle.

At its outset the external iliac vein is directly
behind the artery, and on its right side, also
the commencement of the primitive iliac vein,
the artery crossing the junction of the two
vessels, on that side, obliquely in its descent ;
during the remainder of its course, the vein,
though posterior to it, is also internal ; through-
out the lower half of its course it lies upon
the psoo-i!iac aponeurosis, supported by the os
innominatum, and at first separated from the
bone only by the aponeurosis ; but as it pro-
ceeds separated from it also by the tendon of the
psoas parvus when present, and by the inner mar-
gin of the psoas magnus, it is very near to the os
innominatum, external to the ilio-pectineal emi-
nence, and being here supported by bone, and
made steady by its connections it may with
certainty be compressed and its circulation
perfectly commanded. Internally, the artery
corresponds above to the aperture of the pelvis,
to its viscera more or less intimately, according
to their state of distension or contraction, and
also to the small intestines which descend into
it ; in the lower half of its course, the external
iliac vein, which at its outset is behind or
beneath the artery, is internal, though still some-
what posterior to it ;at the crural arch the artery
and vein are nearly upon the same level, being
supported by the os innominatum ; the artery
however somewhat anterior to the vein, but
as the vein recedes from the arch it inclines
less inward than the artery, and at the same
time retreats more from the surface ; and hence

it gradually gets more completely behind the
artery until at its junction with the primitive
vein it is concealed by it anteriorly.

The artery is covered by peritoneum, upon
its inner side through a considerable part of its
course ; above the membrane covers it com-
pletely ; but as it descends the extent becomes
less in consequence of the ascent of the vein ;
which thus gradually intervenes between the
artery and the membrane, and removes the
latter from it altogether in the lower part of its
course. When the primitive iliac divides at a
high point, the ureter descends into the pelvis
internal to the external iliac immediately after
its origin; this occurs more frequently upon the
right side than the left. Beneath the perito-
neum the artery is covered by an investment, of
which presently again, attaching it superiorly
to the peritoneum and inferiorly to the vein.

Externally the artery corresponds through its
entire course to the psoas magnus muscle, but
it is separated from it by the psoo-iliac fascia, to
which it is connected by its immediate invest-
ment ; the relation of the artery and the
muscle are, however, somewhat different at the
upper and lower parts of the vessel's course;
above, the artery does not lie upon the muscle,
but rests against its inner side along its anterior
part, while inferiorly it lies upon the inner
margin of the muscle at the same time that it
rests against it externally.

The genito-crural nerve is situate along the
outer side of the artery; this nerve, long and
slender, a branch of the lumbar plexus, descends
upon the psoas, extenal to the artery, and at
first at a little distance from it; as it proceeds, it
approaches thevessel,andliesclose to itenveloped
in the fascia propria ; at the lower part of its course
its genital branch frequently passes in front
of the artery. The anterior crural vein is also
external to the artery ; but it is considerably
posterior to it, separated from it by the outer
margin of the psoas, between which and the
iliacus it lies, and also by the fascia iliaca, which
covers it ; the nerve is about half an inch from
the artery at the crural arch ; as it recedes from
the arch the distance increases.

In front, the artery is covered immediately
by a cellular investment, formed by the sub-
peritoneal cellular structure — the fascia propria
— upon the posterior wall of the ilia6 fossa;
this encloses both the artery and the vein and at
the same time connects them ; it varies in its
condition according to the subject, in some it
appears a dense, but still cellular expansion, in
others from the deposition of fat it forms
an adipose stratum, which however still presents
a more condensed character in immediate con-
tact with the vessels ; it adheres closely to the
surface of the fascia iliaca upon either side of
the vessels and thus attaches them to it ; it is
prolonged upward upon the primitive iliac
vessels, and below, it ascends between the
peritoneum and the fascia transversalis upon
the anterior abdominal wall ; upon the primi-
tive iliac it is very thin and proportionally
weak ; but as it descends it increases in thick-
ness and strength until at the lower part of the

ILIAC ARTERIES.

839

external iliac. It forms a stratum of some
thickness and considerable resistance, deserving
of much attention in a practical point of view;
there are imbedded in it immediately above the
crural arch, and superficial to the artery, one or
more lymphatic glands; the genito-crural nerve
also descends enclosed in this structure, at the
outside of the artery. Beneath the investment,
and immediately above the crural arch, an ex-
pansion of limited extent, presenting frequently
a true fibrous or aponeurotic character, arises
from the front of the vessels, and passing
forward becomes identified with the fascia
transversalis upon its internal surface; thus
connecting the vessels to the anterior part of the
superior aperture of the femoral sheath, and
closing the interval between these parts, which
otherwise would be unguarded.

In the second place the artery is covered
anteriorly through about four-fifths of its course
by the peritoneum of the iliac fossa ; in th6
inferior fifth, i. e., for from half to three-fourths
of an inch immediately above the crural arch,
the membrane passing from the front of the
artery to the anterior wall of the abdomen
leaves the iliac artery uncovered ; and hence
the practical inference that the external iliac
artery may be tied without disturbing the
peritoneum.

Beneath the peritoneum the artery is crossed
at the inferior part of its course by the sper-
matic vessels, and at the superior, upon the
right side very frequently by the ureter.

Thirdly, the viscera of the iliac fossa on the
one hand, or of the pelvis on the other, ac-
cording to circumstances, cross or overlap it;
on the right, the coecum and the termination
of the ileum ; on the left, the sigmoid flexure
and the commencement of the rectum, and on
both sides the small intestines are placed in front
of it. And when the viscera of the pelvis become
distended and rise from the cavity they overlap
it from that side.

The third relation of the artery in front is
the anterior wall of the iliac region ; the details
of this it is not proposed to examine at length,
but only so far as they may be concerned in
the relations of the artery ; the structures com-
posing the wall being numerous, they may be
conveniently arranged into three sets, viz., the
superficial, the intermediate, and the deep or
lining structures.

The superficial structures are three, the
skin, the subcutaneous cellular tissue, and the
fascia. Of these the first does not require to
be dwelt upon ; the second is subject to much
variety in its condition ; it forms a stratum of
considerable thickness in every case ; when,
however, the superficial cellular structure of
the body is charged with much adeps, it then
forms an uniform and thick stratum of fat
without any distinction into laminae ; this is
best exemplified at the early periods of life,
particularly in children cut off by an acute
disease ; when, on the contrary, the body is
emaciated, it forms a condensed cellular "ex-
pansion much thinner than in the former case,
and divisible frequently into laminae. This
structure is continued from the iliac over the

other regions of the abdomen, downward upon
the thigh, and in the middle line upon the
spermatic process of the male and the organs
of generation. Numerous superficial vessels
are contained in and ramify through it; these
are derived from several sources, but that which
is proper to the iliac region is the superficial
epigastric artery which ascends from the
femoral superficial to the aponeurosis of the
external oblique muscle and intermediate to
the inguinal rings.

Beneath the subcutaneous stratum is the
third superficial structure, the fascia ; this is a
thin dense expansion by which the external
oblique muscle and its aponeurosis are covered ;
it is not confined to the abdomen, but is con-
tinued into a similar expansion upon the ad-
joining regions whether upward or downward ;
it adheres closely to the muscular portion of
the oblique, particularly at the junction of the
muscular fibres with the aponeurosis along the
linea semilunaris, but its connection to the
aponeurosis itself is more free, an extensible
and delicate cellular tissue being interposed.
Hence it is easily detached from the latter ; it
is most dense, fibrous, and strong upon the
iliac region ; as it ascends thence it becomes
less dense and fibrous, and assumes more of a
simply condensed cellular character ; it is not
equally distinct in every subject, in all it can
be recognized at the crural arch, and for some
distance above it, but as it recedes from the
arch it frequently seems to be gradually re-
solved and to cease. Below, it is attached
posteriorly to the outer edge of the crest of the
ilium, and along this line it meets the insertion
of the fascia lata of the back of the thigh ; in
front between the superior anterior spinous
process of the ilium and the spinous process of
the pubis it descends over the crural arch, having
only a cellular connection to it, and being
separable with ease from it, as well as from
the aponeurosis of the oblique ; immediately
below the arch it is united to the superficial
surface of the fascia of the thigh, both externally
and internally, on the latter side passing back
to the pectineal line of the pubis, into which it
is inserted along with the pubic portion of the
fascia lata; in the interval between the spinous
processes of the pubis it is prolonged down-
ward upon the spermatic processes, and is
continued upon them in the form of a sheath
into the scrotum, where it invests the testicle ; it
is very thin and transparent upon the spermatic
process. The existence of this structure, to
which attention appears to have been first
directed by Camper, can always be demon-
strated however fat or young the subject may
be, though, as has been stated, it is not always
equally manifest ; it seems distinct from th«
subcutaneous cellular structure, which frequently
forms a uniform and thick stratum of fat be-
tween it and the skin. Different views have
been taken of its nature ; by Scarpa it is re-
garded as a prolongation of the fascia lata of
the thigh, while others and the majority consider
it as a continuation of the superficial fascia, so
called, of the same part, and formed by the deep
stratum of the abdominal subcutaneous cellular

840

ILIAC ARTERIES.

structure converted by condensation or removal
of its adeps into an expansion ; to me it appears
that the view taken of its nature by Scarpa is cor-
rect, not in the sense that it is a prolongation of
the fascia lata, but that it is of the same nature,
and that it is to the abdomen the same structure
which the fascia lata is to the thigh ; it is a
question entitled to consideration only for ac-
curacy's sake, but I have frequently verified the
inferior connections of this expansion such as
they have been detailed, and further it appears
to me that it is not properly continuous with
the superficial fascia of the thigh, for if it be
detached from the aponeurosis of the oblique
muscle and the crural arch without injury to its
connection with the fascia lata, and be then
held perpendicular to the latter, the superficial
fascia of the thigh may be removed from the
angle which it will thus form with the fascia
lata, and its connection still remain perfect :
a favourable subject and a careful dissection
will certainly be required for the purpose, but
this circumstance will not invalidate the con-
clusion ; it is also to be recollected in making
the dissection, that the fascia detaches processes
over the inguinal lymphatic glands.

The structures of the second order of parts
concerned with our subject, are the aponeurosis
xof the external oblique muscle, the internal
oblique and the transversalis muscles; of these
the first, which is immediately beneath the
fascia, extends over the entire anterior wall of
the fossa reaching from the linea semilunaris
above to the crural arch below ; internally it is
united with that of the other side in the linea
alba, and inferiorly it forms the crural arch by
its border, which is attached externally to the
superior anterior spinous process of the ilium,
internally to the spinous process of the pubis,
and in the interior to the iliac fascia and the
fascia lata. The direction of this band is to be
borne in mind, for it does not run directly from
one of these points of bone to the other ; but
it descends toward the thigh, and recedes from
the surface at the same time that it passes in-
ward, hence it is concave both forward toward
the surface and upward toward the abdomen ;
the cause of this direction is its connection
inferiorly and posteriorly with the fascia lata
and the fascia iliaca. The aponeurosis consists
primarily of tendinous fibres which run in the
same direction as the fibres of the muscle, i. e.,
downward and inward, parallel to each other,
and also to the crural arch, though rather con-
verging toward it internally, and thereby form
a tendinous expansion ; the longitudinal fibres
of the aponeurosis are crossed by others which
run downward and outward ; these are very
irregular in number and do not interlace with
the former, to which they are superficial ; hence
the aponeurosis does not possess great strength
in the transverse direction, and its longitudinal
fibres are liable to be separated, and deficien-
cies to be thereby formed in the aponeurosis,
which are not unfrequently to be observed.
The superficial inguinal ring is seated in the
aponeurosis ; this aperture, for the particulars of
which see the articles ABDOMEN and HERNIA,
is of variable form and size ; in some cases it

is elliptical, in others triangular ; in the male
it is larger than in the female; its position is
oblique, the longer diameter inclining from the
pubis upward and outward toward the superior
anterior spinous process of the ilium ; its
actual length is extremely variable, in some
instances not amounting to half an inch, in
others exceeding an inch.

The inferior part of the internal oblique and
of the transversalis muscles, which alone is
concerned in the anatomy of this part of the
abdominal wall, may be distinguished into two
parts, viz., their muscular portion and their
aponeurosis. The muscles are both, but more
particularly the latter, very thin, though of
great width; they are placed the one within the
other, and the internal oblique, which is super-
ficial to the transversalis, also descends a good
deal lower, so that its inferior margin approaches
very close to the crural arch, leaving only suf-
ficient space between them for the escape of
the spermatic process, which it covers beneath
the aponeurosis of the external oblique, and
which in some instances passes between its-
fibres,* while the margin of the transversalis is
at some distance from the arch, and rarely
covers the process, at least to any extent, the
process escaping from the deep ring, for the
most part below the margin of the muscle ;
Cloquet has even seen the margin of the muscle
so far as two fingers' breadth above the point of
escape of the cord, arid its fibres are usually
pale, fine, and scattered. The muscular fibres
of the lower part of the two muscles are at-
tached to the anterior extremity of the crest of
the ilium and to its spinous process, also to the
superior aspect of the outer part of the crural
arch, the oblique to nearly the outer half of
the arch, the transverse to the outer third or
fourth, but the ultimate attachment of the
latter is to the surface of the fascia iliaca above
the arch, to which they adhere very intimately
as they pass forward from the fascia ; they run
inward nearly transversely, but convex forward
in proportion to the prominence of the abdo-
men, those of the oblique over the deep ring,
and the spermatic process within the inguinal
canal, those of the transverse above the ring,
until they have both passed that point ; they
then descend along the inside of the process,
and at the same time recede from the surface so
that they become posterior to it, and terminate
as they descend in a thin irregular aponeurotic
expansion common to the fibres of both mus-
cles, and thence denominated " the conjoined
tendon ;" though designated by an especial
name, this is in reality only the inferior part of
the general conjoined tendon of the two mus-
cles which terminate between the umbilicus
and the pubis in a common expansion ; this is
placed superficial to the rectus muscle, and is
inserted into the linea alba, the anterior margin
of the crest of the pubis as far as its spinous
process, and thence outward into the pectineal
line of the bone, there forming the " conjoined
tendon" of the anatomy of hernia. This struc-
ture is situate behind the spermatic process,

* Cloquet.

ILIAC ARTERIES.

841

between it and the fascia transversalis ; it ap-
proaches very near to the inner margin of the
deep ring, and at its insertion into the pectineal
line it meets and is identified with Gimbernat's
ligament; it is closely adherent to the surface of
the fascia transversalis, and hence that fascia
presents an appearance of thickness and strength
upon the inside of the deep ring, which it does
not really possess. From the inferior margin
of the internal oblique and from the superior
side of the crural arch the cremaster muscle
descends upon the anterior and external part of
the spermatic process, forming one of the
coverings of the process within the inguinal
canal, of course concealing it after the division
of the aponeurosis of the external oblique, and
requiring to be detached from the arch along
with the~lower fibres of the internal oblique in
order that the process may be fairly exposed.

The deep structures of the anterior wall of
the iliac fossa are also three, viz., the fascia
transversalis, the fascia propria, and the peri-
toneum.

1. The fascia transversalis is most remark-
able in the iliac region, but it is not con-
fined to it, being to be traced upward to
the surface of the diaphragm, and backward
round the interior of the lateral walls of the abdo-
men. In the iliac region this fascia is inferiorly
first identified with the fascia iliaca from a short
distance behind the anterior superior spinous
process of the ilium to the outer side of the
external iliac artery, or about the middle of the
crural arch ; the line of its connection with the
fascia iliaca runs downward, forward, and in-
ward, at a short distance within the crest of
the ilium and the crural arch, approaching the
latter, however, as it descends, until at the
outside of the artery it touches it ; it is sepa-
rated along this line into two laminae which
enclose the circumflex iliac artery between
them ; there is, therefore, an interval between
the arch and the line of connection of the two
fasciae in which the fascia iliaca intervenes, and
to the surface of this part of the fascia it is
that the internal oblique and transverse muscles
are attached. In the second place the fascia
transversalis descends into the thigh beneath
the crural arch, between it and the iliac vessels,
and forming the front of their sheath; and,
thirdly, it is attached upon the inside of the
vessels, along the pectineal line of the pubis
posterior to the conjoined tendon of the internal
oblique and transverse muscles, between it and
the peritoneum, and separated by it from the
spermatic process, which is in front of both.

Internally the fascia transversalis is con-
nected to the edge of the tendon of the rectus.

Midway between the superior anterior spi-
nous process of the ilium and the spinous pro-
cess of the pubes, and at from half to three-
fourths of an inch above the crural arch, the
spermatic process escapes from the abdomen,
descending within a cylindrical prolongation of
the fascia by which the process is enclosed, and
which thus forms a sheath for the process. By
detaching this prolongation from the fascia
around the process, a circular aperture is
formed in the fascia, which is the deep in-

guinal ring, the situation of which has been
just defined. On the inside of this opening-
are situate the epigastric vessels, the artery f
and vein or veins, the artery in the former case
being next the ring, in the latter at times the
outer of the two veins.

2. The fascia propria is a cellular stratum in-
terposed between the peritoneum and the struc-
tures of the abdominal walls which it lines ; it
varies in thickness and condition at different
parts and in different subjects ; at times it con-
tains adeps, at others it is purely cellular, or
forms a condensed expansion ; in the iliac
region it is thicker upon its posterior than its
anterior wall ; on the latter it increases in
thickness as it descends towards the crural
arch, being so thin towards the umbilicus that
the peritoneum adheres very closely to the ten-
dinous expansion of the muscles ; at the deep
inguinal ring it is more dense, and the perito-
neum, the fascia transversalis, and it, are more
intimately connected than at either side; ex-
ternal to the ring, between it and the spinous
process of the ilium, it is so free that the pe-
ritoneum may be separated without difficulty
from the interior of the fascia transversalis,
and along the crural arch it forms, from the
external iliac artery outward, a soft mass,
sometimes thick, occupying the interval left
between the peritoneum and the fascia trans-
versalis, at the reflection of the former from
the iliac fossa to the anterior wall : upon this
wall it encloses the epigastric vessels, the um-
bilical ligament, and the spermatic vessels, and
not only does it extend universally over the in-
terior of the abdominal walls but it is prolonged
through their several apertures upon the parts
which pass through them, as in the case of the
spermatic vessels.

From the anterior wall of this region it passes
to the posterior, where it lines the iliac fossa,
and connects the peritoneum or the viscera to
the iliac fascia ; at the outer part of the fossa
it is remarkably free, soft, and easily lacerated,
so that the peritoneum can be detached, pro-
bably with greater facility at this than at any
other situation; at its inner part it is even more
abundant, thicker the nearer to the crural arch,
forming the investment by which the iliac ves-
sels are inclosed, and descending thence into
the pelvis.

Lastly, the peritoneum of the anterior wall
is continuous inferiorly with that of the iliac
fossa, being reflected from the one to the other
at the distance of five or six lines above the
crural arch — a fact deserving of much attention,
since it permits the external iliac artery to be
secured without disturbing the membrane. In
its reflection from one wall of the region to
the other it leaves immediately above the crural
arch, between itself, the fascia transversalis,
and the fascia iliaca, a triangular interval of
some lines, occupied by the fascia propria,
and at times at least by one or more lymphatic
glands ; this space is widest at the iliac artery
and diminishes as it extends outward ; this fact
also deserves attention, inasmuch as it points
out where the fascia transversalis may be di-
vided, if necessary, in the operation of expo-

842

ILIAC ARTERIES.

sing the external iliac with least danger to the
peritoneum, viz. on the outside of the deep
inguinal ring and close as possible to the crural
arch. The peritoneum of the anterior wall of
the fossa is weaker toward the middle line
than externally; it presents toward the abdo-
men two depressions or recesses denominated
by Velpeau " fossettes inguinales," internal
and external ; these depressions vary veiy much
in their depth, sometimes hardly perceptible,
at others of considerable depth and capacity,
more especially the external, which is much
the larger; they are produced by the projection
of the umbilical ligament from the interior of
the abdominal wall, and the reflection of the
peritoneum round the ligament, by means of
which a triangular fold, wide in proportion to
the degree to which the ligament projects, is
formed, the base of which is below, the apex
above toward the umbilicus, and in the free
edge of which the ligament is contained ; this
fold separates the depressions, one being
external to it, the other internal, between it
and the urachus ; the external one, the bottom
of which tends forward and inward, corresponds
to some point of the posterior wall of the in-
guinal canal, but its precise relation to it is
uncertain, because of the irregularity of the
position of the umbilical ligament ; at times
it is identical with another slight depression
situate on the outside of the epigastric vessels,
which marks the situation of the deep inguinal
ring, the ligament in such case being behind
these vessels ; at others it corresponds to the
wall of the canal, to the superficial inguinal or
the deep femoral rings, the ligament being in
these latter cases internal to the epigastric
vessels.

The branches of the external iliac artery de-
serving of particular attention are usually two,
the anterior or circumflex iliac and the epigas-
tric arteries; throughout the superior part of its
course the artery gives only minute branches to
the peritoneum, the cellular tissue, the psoae
muscles, and the lymphatics; the other two,
which have been mentioned, are given off im-
mediately before the artery escapes from the
abdomen. They arise at a very short distance
above the crural arch, sometimes so high as
three-fourths of an inch from it, at others at it,
and sometimes again below the arch from the
femoral ; they proceed one from the outer and
the other from the inner side of the vessel,
sometimes opposite to each other, at others in-
differently one above the other; occasionally
they are given off from a trunk common to
both; they are nearly of equal size, but for the
most part the epigastric is larger than the cir-
cumflex.

1. The anterior or circumflex iliac artery,
(arteria circumflexa iliaca or ilii ; Fr. artere
circonflexe iliaque, ou iliaque ou anterieure,)
arises from the outer side of the external iliac
on a level with or somewhat lower than the
epigastric; it runs outward and upward above
and parallel to the crural arch as far as
the superior anterior spinous process of the
ilium ; during this course it lies upon the fascia
iliaca superficial to the psoas and iliacus mus-

cles and the anterior crural nerve, and it is
inclosed in a triangular canal, formed behind
by the fascia iliaca, below and above by la-
minae of the fascia transversalis, which divides
at its union with the former, in order to inclose
the artery. When the anterior abdominal wall
has been thrown down, and the peritoneum
with the fascia propria removed from the iliac
fossa, the course of the vessel may be traced by
a white line, which marks the union of the two
fasciae, extending from the middle of the crural
arch upward and outward within about three-
fourths of an inch of the spinous process of
the ilium; by the division of the fascia trans-
versalis along this line the artery will be ex-
posed.

During its course toward the spinous process
the artery gives branches to the psoas and
iliacus, the transversalis and oblique muscles,,
and to the inguinal glands ; near the process it
gives upward a considerable branch, which
ascends in the anterior wall of the abdomen
between the internal oblique and transversalis
muscles, in front of the spinous process, serving
with its accompanying veins as a guide in dis-
section by which to distinguish between the-
two muscles; it divides into branches, which
are distributed to the muscles, as also to the
structures, which cover and line them, and
communicate with branches of the epigastric,
lumbar, and intercostal arteries.

The circumflex artery pursues its course and
runs backward around and within the crest of
the ilium, internal to the transversalis muscle ;
during its course it gives branches inward to
the iliacus muscle which anastomose with si-
milar branches from the iliolumbar, and up-
ward to the lateral abdominal muscles, which
are partly distributed to them, partly turn over
the crest of the ilium and communicate with
the gluteal artery, and in part communicate
with the lumbar or intercostal arteries. Finally,
the artery, very much reduced in size, anasto-
moses freely with the termination of the ilio-
lumbar, which pursues a similar course in a
contrary direction around the interior of the
crest of the ilium.

The circumflex artery has been found by
Monro to present an irregularity deserving of
notice ; he has seen a branch from it, nearly as
large as the epigastric, pass under the crural
arch, about two inches from the symphysis
pubis, and there divide into branches, which
were distributed upon the symphysis and the
fat and skin over the arch.

2. The epigastric artery, (Fr. artere epigas-
trique, A. sus-pubienne) arises from the in-
ternal and rather anterior part of the iliac
artery, near to the crural arch ; the distance
of its origin from the arch, however, is liable
to variety ; for the most part it occurs about
half an inch above it, but it is frequently
nearer to it, or even at it, and occasionally it
is below it, arising from the femoral artery ; it is
given off, as has been stated, from that part
of the iliac, which is left uncovered by peri-
toneum, and its point of origin is posterior to,
sometimes above, sometimes on a level with,
and at others below the reflection of the mem-

ILIAC ARTERIES.

843

brane from the posterior to the anterior wall of
the abdomen. Its course is tortuous ; it passes
forward and inward ; when its origin is low, or
very near to the arch, at once upward; but
when its origin is high, at first downward in
front of the external iliac vein, and then
changing its direction, when it has reached the
reflection of the peritoneum, it ascends inward
toward the outer margin of the rectus muscle,
in front of the membrane, between it and the
fascia transversahs ; it reaches the margin of
the muscle from one and a half to two inches
above the pubis, and then passing behind it
enters its sheath, and continues its course upon
the posterior surface of the muscle toward the
umbilicus, and terminates by dividing into
branches, which anastomose freely with de-
scending branches of the internal mammary
artery ; the main course of the vessel is there-
fore oblique upward and inward ; and it may
be defined by a line drawn from the junction of
the middle and inner third of the crural arch to
within half an inch upon either side of the
umbilicus.

The artery, when its origin is high, is situate,
at its outset, behind the peritoneum, posterior
to the deep inguinal ring ; in the rest of its
course it is at first beneath and then before it,
in immediate contact with it from the crural
arch to the edge of the rectus, and enclosed in
the fascia propria, but in the remainder sepa-
rated from it by the back of the sheath of the
muscle ; it therefore forms in this case a curve
in which the reflection of the peritoneum is
contained, and through which the vas deferens
forms a similar curve, — the aspect of the curves
being however different, the convexity in the
former directed downward, and in the latter
outward and somewhat upward — the two cords
hooking round each other; in its ascent from
the crural arch it is contained in the posterior
wall of the inguinal canal, between the fascia
transversalis and the peritoneum, crossing the
canal nearly at right angles, and intermediate
to the two rings, being distant from the outer
part of the superficial one, according to the
size of the aperture, from half an inch to an
inch and a half, and in its relation to the deep
ring varying from the margin of the aperture
itself to four or five lines distance from it. It
is accompanied sometimes by one, at others by
two veins; in the former case the artery is
always external and next to the margin of the
ring ; in the latter, one of the veins is at times
between it and the aperture.

The relation of the artery to the inguinal
rings indicates at once that which it must hold
to the neck of the sac in the two original forms
of inguinal hernia ; in the oblique or external
inguinal hernia it is, as a matter of course, placed
beneath and on the inside; and in the direct or
internal inguinal, upon the outside of the
neck ; but in the former it must, in consequence
of its natural vicinity to the ring, and the dila-
tation of the latter, be close to and surround
the neck upon the two sides mentioned, while
in the second, unless the aperture be much
enlarged, it will be at a greater or less distance
from it ; the risk of danger to the vessel from

cutting to the side, at which it lies, in a stran-
gulation at the neck of the sac, must therefore
be much greater in the former than in the
latter. In the case of a hernia originally ob-
lique and become direct by long continuance,
the artery carried inward along with the deep
ring, from the displacement of which the
hernia assumes the character of the direct form,
the artery is of course situate still upon the
inside of the neck, which at the same time it
surrounds to a greater extent than in the former
instances ; this third, though secondary, form of
inguinal hernia presents another case, in which
the relation of the vessel to the neck of the
sac demands attention the more that the true
nature of the case being obscure and the
hernia originally and secondarily direct, being
thence liable to be confounded, it is most im-
portant that it should be borne in mind that
the artery may be to the one side or the other,
according as the hernia has been originally or
secondarily direct. The epigastric artery is
also situate, in its ascent, external to the deep
femoral ring ; its distance from it, in the natural
state, is about half an inch ; but when hernia
is present, and the neck at all large, the epi-
gastric vessels are close to its outer and anterior
side, the vein, however, being between the
artery and the ring ; when the obturator artery
arises from the epigastric, the propinquity of the
latter to the ring is increased.

The branches of the epigastric artery are
numerous, and some of them important. Its
first branches are two given off between its
origin, and the deep inguinal ring, higher or
lower, according to the situation of the origin
of the epigastric itself; they arise, in some in-
stances separately, in others by a single origin,
and they run over to the posterior surface of
the pubis, the other to anastomose with the
obturator artery ; the former, the pubic branch,
runs inward above Gimbernat's ligament,
sometimes along its anterior, sometimes along
its posterior margin, to the back of the
pubis, and according to its course is liable
to be situate before or behind the neck
of a femoral hernia. The second, the obtu-
rator branch, runs backward, downward and
inward toward the superior aperture of the pelvis,
i.e. in the direction, which the obturator artery
when arising from the epigastric takes ; having
descended into the pelvis it joins the obturator
at a variable distance between the origin of
that vessel from the internal iliac and the sub-
pubic foramen; frequently it divides at the
brim of the pelvis into two, of which one
joins the obturator and the other runs backward
along the brim and anastomoses with the ilio-
lumbar artery. This branch holds precisely the
same relation to femoral hernia which the
obturator when arising from the epigastric does;
it is very variable in size, and it is upon its de-
velopment as compared with that of the origin
of the obturator from the internal iliac that
depends, whether the former shall seem a
branch of the latter, or of the epigastric ; when
the origin of the obturator from the iliac has
become wanting, this branch takes its place
and becomes the obturator.

844

ILIAC ARTERIES.

2. The epigastric artery in passing the deep
inguinal ring gives a branch, which goes out
through the ring in company with the spermatic
process, descends to the scrotum and is distri-
buted to the structures of the cord, to the
tunica vaginalis, and to the cremaster, and anas-
tomoses with branches of the spermatic artery;
it is denominated by some the inferior sper-
matic artery.

3. As the artery ascends in the abdominal
•wall it gives to either side numerous branches,
which are distributed among the structures of
the wall, anastomosing externally with branches
of the circumflex iliac, of the lumbar and the
inferior intercostal arteries, and internally with
those of the artery of the other side ; many of
these branches ultimately become superficial,
passing through the muscles, and through aper-
tures in the aponeurosis of the external oblique ;
they terminate in the superficial structures,
anastomosing with the other superficial vessels.
4. Finally, the epigastric artery terminates by
two or more long ascending branches, which
meet and anastomose with branches from the
internal mammary artery.

Methods of operation for the ligature of the
iliac arteries. — The methods of operation for
the internal and primitive iliacs being but mo-
difications of those adopted for the external, I
propose to detail the latter first.

The operation in each case may be resolved
into three stages, viz. 1, the division of the
structures of the abdominal wall ; 2, the dis-
placement of the peritoneum with the inter-
vening viscera; 3, the management of the
artery and the parts immediately related to it.
Several plans have been proposed for exposing
the external iliac artery ; these may be regarded
as, all, modifications of the same ; yet their
number, the existence of points of difference
leading to results of some importance, and the
advantage to be derived from a clear appre-
hension of them, render it desirable to distin-
guish them so far as they present distinctive
characters deserving notice. I propose, there-
fore, to particularize five methods, between
which operators may have occasion to select.
In the first the line of incision is straight, and
corresponds to the course of the artery. In the
second the line of incision is also straight, and
inclines away from the course of the artery
toward the superior anterior spinous process of
the ilium. In the third the line of incision is
curved, convex downward toward the thigh, and
crosses the course of the vessel. In the fourth
the line of incision is straight, and transverse to
the artery's course. The fifth, which I would
specify, is a modification of the third, by which
that plan may be rendered more generally ap-
plicable. The first is, that which was adopted
by Abernethy, by whom the artery was first
tied, A.D. 1796, and is now generally known as
his method, of which the following is his own
account : — " I first made an incision, about
three inches in length, through the integuments
of the abdomen, in the direction of the artery,
and thus laid bare the aponeurosis of the ex-
ternal oblique muscle, which I next divided
from its connection with Poupart's ligament, in

the direction of the external wound, for the
extent of about two inches. The margins of
the internal oblique and transversal is muscles
being thus exposed, I introduced my finger
beneath them for the protection of the peri-
toneum, and then divided them. Next, with
my hand I pushed the peritoneum and its con-
tents upwards and inwards, and took hold of
the artery."*

The second method seems due to several,
and first also to Abernethy. This may seem
doubtful, from the account of his second ope-
ration originally given by himself, in which he
says merely that " an incision of three inches
in length was made through the integuments
of the abdomen beginning a little above Pou-
part's ligament, and being continued upwards ;
it has more than half an inch on the outside of
the upper part of the abdominal ring, to avoid
the epigastric artery."f But in his collected
works}; of different dates it is expressly stated
of this and his subsequent operations that the
incision "began just above the middle of
Poupart's ligament, and consequently external
to the epigastric artery, and was continued
upwards, but slightly inclined towards the
:i: — » Tne p|an adopted by Frere differed

ilii

not much from this. This method appears
however more particularly attributable to lloux,
who seems to have been the first to give specific
instructions for it, recommending that the be-
ginning of the incision should never be further
than half an inch from and a very little higher
than the anterior superior spine of the ilium,
and that it should be carried very obliquely
downwards to the middle of Poupart's liga-
ment^

The third method is that of Sir A. Cooper,
in which the incision is begun just above the
abdominal ring, and is extended downward in
a semilunar direction to the upper edge of
Poupart's ligament, and again upwards to
within an inch of the anterior superior spinous
process of the ilium. This incision exposes
the tendon of the external oblique muscle : in
the same direction the above tendon is to be
cut through, and the lower edges of the in-
ternal oblique and transversalis muscles ex-
posed : the centre of these muscles is then to
be separated from Poupart's ligament : the
opening by which the spermatic cord quits the
abdomen is thus exposed, and the finger passed
through it is directly applied upon the iliac
artery above the origin of the epigastric and
circumflex ilii arteries: the next step of the
operation consists in gently separating the vein
from the artery by the extremity of a director
or the end of the finger ; the aneurismal
needle is then passed under the artery. ||

The fourth is that of Bogros, in which the
line of incision is, as I understand it, straight,
from two to three inches long, immediately
above the crural arch, and has its extremities

* Surgical Works, 1830, v. 1, p. 292.
t Surgical Observations, 1804, p. 214.
t Surgical Works, 1830, p. 396.
§ Cooper's Dictionary, and Nouveaux Elemens dc
Med. Op.

|| Cooper's Lectures by Tyrrell, v. 11.

ILIAC ARTERIES*

845

equidistant, the external from the spine of the
ilium, and the internal from the symphysis of
the pubis. The aponeurosis of the external
oblique muscle having been laid open -in the
direction of the crural arch upon a grooved
director, the spermatic cord with the cremaster
is to be drawn upward beneath the superior lip
of the wound ; the deep ring dilated with the
point of the finger ; the epigastric vessels, if
a guide be necessary, followed toward their
oriain ; the cellular structure and lymphatic
glands situate above the arch upon the artery
separated ; and the vessel exposed and
isolated.*

In the fifth method, which is but a modi-
fication of Cooper's, the outer extremity of
the incision as directed by him is prolonged
to, or beyond the superior spinous process of
the ilium in proportion to circumstances.

Before these methods be contrasted with
each other, a few additional remarks seem re-
quired in reference to the operation however
performed.

1. The posture of the patient should be such
as will most relax the abdominal muscles in
order to prevent as much as possible their
pressure upon the viscera, and to allow the
more easy separation of the edges of the wound.
The shoulders should be raised and the legs
bent upon the pelvis.

2. It seems desirable that unless the super-
ficial wound be longer than has been stated,
the division of the aponeurosis of the external
oblique should be of equal extent.

3. The recommendation to divide that apo-
neurosis upon a director appears judicious as
a means both of facility and safety.

4. Where it can be used the finger seems a
safer instrument with which to separate the
internal oblique and transversalis muscles from
the structures beneath, for it will be readily
understood that the extremity of a director
might be easily thrust through the peritoneum
in the execution of this step.

5. It must be borne in mind that between
the muscles and the artery there are to be ex-
pected beside the peritoneum two other struc-
tures : 1. the fascia transversalis; 2. the im-
mediate investment of the vessels. The fascia
transversalis may either be treated in the manner
directed by Cooper, viz. by dilating the deep
ring, or be lacerated with the nail, as recom-
mended by Guthrie, but it is to be recollected
that a prolongation of the fascia descends upon
the spermatic cord, and that therefore there
exists no opening, and that the fascia varies
in strength, and may at times be found so
strong as to require more force to lacerate it
than it may be deemed proper to exert. In
such case an opening may be made through it
with the knife, and enlarged upon a director
if necessary. This may be effected by either
of two methods, viz. either by dividing the
prolongation of the fascia, which descends
upon the spermatic process, " having been first
raised with a forceps, to a sufficient extent to
admit the forefinger to pass upon the cord into

* Archives Gentrales de Med., t. iii. p. 408.

the internal abdominal ring," — a proceeding
adopted by Mott, and which offers a safe mode
of opening that structure ; or by cutting the
fascia upon the outside of the ring, in the di-
rection toward the superior spine of the ilium,
to such an extent as may allow the introduction
of the director or the finger : the section can-
not be attempted safely inward, because of the
vicinity of the epigastric artery, which is so
near to the inner side of the deep ring that it
must in such case be exposed to imminent
danger, situate as it is between the fascia
and the peritoneum ; on the other hand the
more close attachment of the fascia to the latter
membrane in proportion as it recedes from the
crural arch forbids the section of the fascia di-
rectly upward ; while the existence of the tri-
angular interval, which has been described,
between the fascia and the peritoneum imme-
diately above the arch renders the membrane
safe from injury in a division outward near to
the arch : it must however be recollected that
in approaching the arch the circumflex ilii
artery is also approached and endangered, so
that the incision should not be brought too
near to that part, but made in the direction
mentioned, nor in any case be larger than will
suffice for the introduction of the finger or the
director.

6. The immediate investment of the vessels
frequently opposes great resistance to the sepa-
ration of the artery and vein, and to the iso-
lation of the former; this impediment is due
not merely to the strength of the investment,
but also to the absence of a resisting support
behind the vessel as it recedes from the pubis,
in consequence of which it yields to the pres-
sure exerted to separate it. In such case the
nail, the director, or the knife has been recom-
mended for the division of the expansion;
Abernethy made a slight incision on either side
of the artery. The nail does not seem the best
instrument in this instance, because, by the
use of it the vessel must be a good deal dis-
turbed, a circumstance to be avoided when-
ever it can be ; the knife again must be attended
with risk unless used with great caution and
in steady hands, and the risk is the greater
when the incision is made at one side of the
artery, since the vein is thereby endangered ;
it would seem a safer proceeding and one less
likely to disturb the artery unnecessarily, if,
when it can be done, the investment were
pinched up with a forceps over the middle of
the artery and then divided to the extent to
which it may have been raised, after which,
with the director or the blunt aneurism- needle,
the artery may be isolated with facility while
the investment is drawn to either side with the
forceps.

7. It is to be borne in mind that one or
more lymphatic glands usually lie in front of
the artery imbedded in the cellular structure
which forms its investment, and that these
may be to be displaced.

8. In operations upon the iliac arteries, more
particularly when performed after the method
of Abernethy, or upon the internal or primi-
tive vessels, a protrusion or bearing down of

846

~ ILIAC ARTERIES.

the abdominal viscera is to be expected which
has been found a great obstruction to the
operation : this will be most effectually pre-
vented by the use of purgatives previous to the
operation; by posture, the abdominal muscles
being thereby relaxed as much as possible;
and during the operation, if it occur, by the
use of curved spatulas of considerable width
and curve, as used by Mott, with which the
viscera may be supported.

9. In the passage of the ligature it will
always be necessary to be assured that the
genito-crural nerve is not included ; but it may
be avoided without difficulty, and can seldom
require to be divided. Its situation should be
borne in mind, viz. above external to the artery,
below external or anterior.

Lastly, it would seem the safer plan to pass
the needle and ligature from within outward,
inasmuch as the vein is internal to the artery.
In Cooper's Lectures edited by Tyrrell, it is
directed to pass the needle from without; by
so doing there is less risk that the genito-crural
nerve shall be included, and in high operations,
since the vein is situate so much beneath the
artery at the superior part of their course, it
will not be thereby much endangered, but at
the lower part the vein must certainly be more
exposed by that mode of passing the ligature
than by the contrary one, while the nerve may
be avoided without difficulty.

We shall next consider the comparative
merits of the several plans of operation. In
the method of Abernethy the direction of the
line of incision is attended with the following
consequences. 1 . It requires a more extensive
division of the oblique and transversalis mus-
cles, and hence is more likely to be followed
by weakness of the abdominal wall. 2. Fal-
ling, as first performed by him, nearly upon
the course of the epigastric artery, it exposes
that vessel to be divided, though in the me-
thod adopted by him in his latter operations
this risk must be very much diminished, if not
removed. 3. The extent to which it is neces-
sary to divide the internal oblique and trans-
versalis muscles must expose the peritoneum
lining the anterior wall of the abdomen to be
lacerated or divided during their separation.
4. The parallelism of the vessel and the wound
must render it necessary to expose a greater
length of the former, in order to effect its
separation from the contiguous parts and to
pass a ligature round it. 5. It is therefore
necessary to detach the peritoneum in all cases,
and to a greater extent than may be necessary
or required by a different method. 6. The
peritoneum must be detached to an equal ex-
tent from both walls of the abdomen — from the
anterior as much as, or it may be more than,
from the posterior. 7. The protrusion of the
viscera must be more likely to occur.

It is asserted by some* that the spermatic
cord is more exposed to injury in this method;
but it appears to me that it cannot be more so
than in others, and that it ought to be more
safe.

* Velpeau.

The second method is free from many objec-
tions to which others, and especially the first,
are exposed. 1. It does not endanger any
vessel but the superficial epigastric. 2. It does
not endanger the spermatic cord. 3. Probably
it does not tend to weaken the abdominal wall
as much as the first method. 4. It renders
necessary a much less extensive detachment of
the peritoneum, since the line of incision falls
so much nearer to the inferior reflection of the
membrane. Add to these that by it the artery
may be reached at as high a point as by the
first, and no doubt can remain that it is to be
preferred to it ; and in cases requiring a high
ligature of the vessel there is none, save the
modification of Cooper's method, which can
be considered equally eligible. It is still,
however, subject to the same conditions with
the first, only in less degree. In the method of
Cooper, on the contrary, the internal oblique
and transversalis muscles are divided to but an
inconsiderable extent, and the division of the
aponeurosis of the external oblique approaches
more to the course of its fibres. The direc-
tion of the incision being transverse to that of
the artery, the vessel may be exposed, and a
ligature passed round it without stripping it to
a great extent and with little disturbance of it.
Again, for the same reason and because of the
vicinity of the incision to the crural arch, the
vessel may be exposed either without dis-
placing the peritoneum at all, or displacing it
but little ; and when it is necessary to displace
the membrane, that may be effected with the
least possible disturbance of it, inasmuch as,
because of the propinquity of the line of in-
cision to the reflection of the membrane, it is
not necessary to detach the latter from the
anterior wall of the abdomen. It must also
be less exposed to the protrusion of the viscera,
and when the vessel is tied below, the reflection
of the peritoneum must be exempt from it.
This method permits the artery to be reached
at from an inch to an inch and a half above the
crural arch.

On the other hand this method endangers
the epigastric artery and spermatic cord more
than the others ; the former because the line
of incision crosses the vessel's course, com-
mencing internal to it, and the latter because
the line of incision crosses and sweeps over
tne cord in describing its curve. Velpeau con-
siders that there is greater danger to these parts
in the method of Abernethy, but I cannot
concur in this opinion, for the lower extremity
of the incision alone can fall upon the situation
of the cord, and in the mode adopted by him
in the majority of his operations, the line of
incision was external to that of the epigastric
artery. Experience too proves that there is
greater danger of dividing the epigastric artery
in the method of Cooper, since the accident
has occurred more than once in it, and in the
most dexterous hands; thus Averill relates that
the artery was wounded by Dupuytren, and
Guthrie also states that he has seen the artery
divided in the performance of this operation,
while I am not aware of an instance in which
the trunk of the artery has been divided in the

ILIAC ARTERIES.

847

method of Abernethy. But these objections
to the method of Cooper, however serious in
themselves, seem of insufficient weight when
contrasted with those to which the plan of
Abernethy is subject, more especially since
they only require caution to be effectually ob-
viated, while the others are inseparable from
the plan to which they apply. And hence the
preference has been given to his method, by
the greater number of those* who have had
opportunities of experimentally testing the
comparative claims of the two in all cases
where it is applicable : i. e. in those instances
in which the aneurismal tumour has so little
encroached upon the crural arch, or in which
there is so much reason to consider the artery
in a healthy condition immediately above the
arch, that it may be with propriety tied near
to that part. Sabatier is of opinion that the
method of Abernethy should be preferred in
every case; but the number of authorities
in favour of the other is so great, that we must
consider its greater eligibility as a decided
question. And the method of Cooper pos-
sesses the additional and great recommendation
that it may at any time be so modified by the
prolongation of the upper extremity of the in-
cision, as to be adapted to every case, so that
in instances, in which it may be found neces-
sary to tie the artery at a greater distance from
the arch than the original plan will permit,
this modification of it may be adopted even in
the course of the operation : for the most part
surgical writers recommend a preference of
Abernethy 's first plan in such circumstances;
but to this all the same objections which have
been already stated, apply, and forbid its adop-
tion, while another less subject to them and
not less efficacious presents for selection.
Abernethy's plan certainly promises one ad-
vantage, viz. that the line of incision being
nearer to that of the artery the depth of it from
the surface is likely to be less, unless where
the abdomen is very prominent, than in the
latter, in which the obliquity of the direction
must increase the depth of the wound, and for
the same reason it may be more easy to obtain
a view of the vessel, and to direct the opera-
tion by the sight, which must be more difficult
in the latter, and in proportion as the point at
which the operator aims is higher ; yet, not-
withstanding this circumstance in favour of the
method of Abernethy, and the preference given
by several to it in such cases, the method of
Cooper, modified as has been explained, ap-
pears to me still preferable, inasmuch as the
greater disturbance of the peritoneum, the risk
of injuring it in front, and the greater debility
of the abdominal wall likely to be the con-
sequence of Abernethy's method, seem to out-
weigh its advantages : there is beside another
disadvantage attending the latter and a cor-
responding advantage attending Cooper's plan,
which must be experienced when an aneuris-
mal tumour occupies the iliac fossa, viz. that,
by the former the peritoneum must be detached
from all the front of the tumour, while in the

* Norman, Todd, Velpeau.

latter the lower and inner part of it may be
left undisturbed, and this I consider a matter
of some importance.

The method of Bogros has been proposed as
an improvement upon that of Cooper, under the
impression that in the latter the incision, which
makes nearly a right angle with the artery,
corresponds to the vessel only by its internal ex-
tremity, while in the one which Bogros proposes
the middle of the incision corresponds directly
to the artery ; by this plan he further maintains
that greater facility in the operation is ob-
tained, and the artery may be exposed nearly
an inch above the crural arch without disturb-
ing the peritoneum, while in Cooper's the
membrane must be always displaced, and the
ligature can be applied at only a very short
distance from the arch. Bogros plainly under-
stands Cooper's incision to commence at the
internal abdominal ring, and in such case his
objections would be well founded. It is cer-
tainly to be regretted that Cooper has used an
ambiguous expression, which has led others
beside Bogros to mistake his meaning ; but if
reference be made to his description of the
anatomy of hernia it will be found that by the
" abdominal" he intends the superficial in-
guinal ring, and if so, that the sole difference
between his and Bogros' plan is that in one the
line of incision is straight while in the other it
is curved, whence the comparative results must
be the reverse of those inferred by Bogros, so
far as the facility of securing the artery and of
reaching it at a greater distance from the crural
arch is concerned. If however it be desired to
secure the artery immediately above the crural
arch, between it and the reflection of the peri-
toneum, as may occur in cases of femoral
aneurism, the method of Bogros furnishes a
plan fully adequate to the intention, free from
the necessity of disturbing the peritoneum and
easy of execution ; at the same time that it is
subject to the objection, that, unless care be
taken to prevent it by tracing the vessels to
their origin, which must render the operation
more complicated and delicate, the artery is
more likely to be tied below the origin of the
epigastric and circumflex arteries by this than
by any other plan, and this upon two accounts
had better be avoided, so that all things con-
sidered this plan appears to me not so eligible
as that of Cooper, in which it is altogether
optional with the operator whether he shall
disturb the peritoneum or not, or whether he
shall tie the vessel immediately above the arch
or farther from it, the one method being ap-
plicable to all cases, and not requiring, perhaps
during the operation, a transition to another,
after that the first has been found insufficient.

The modification of Cooper's plan, which
has been enumerated as a fifth method, can be
required only in those cases, in which it may
be necessary to reach a very high point of the
external or the primitive iliac. In such it will
be a question whether to adopt Abernethy's
original method, the second method, or the one
under consideration : for myself it appears to
me that the first ought to" be abandoned in
operations upon the external or primitive iliacs,

848

ILIAC ARTERIES.

unless there be something peculiar in the par-
ticular case to justify its adoption. The ad-
vantages of the second method have been
partly stated ; to these is to be added that the
line of incision will be made to correspond more
to that of the artery than by the last method,
and consequently the wound will be less oblique
in depth, whence probably there will be less
difficulty experienced in holding aside the parts
which intervene between the surface and the
vessel; and certainly the operator, who may
be apprehensive of injuring the epigastric and
circumflex iliac arteries or the spermatic process,
will do well to adopt it. Still for some reasons
I feel disposed to prefer the last, for 1, it re-
quires less disturbance of the peritoneum ; 2,
it appears to me that the exposure of the vessel
must be greatly facilitated by carrying the lower
extremity of the incision across the course of
the artery to its inner side, which is not accom-
plished by the second method ; 3, a semilunar
line of incision furnishes a wound of greater
length, and capable of being more widely
opened than a straight one, while caution will
secure the spermatic process and the epigastric
artery from injury; and if a branch of the
circumflex ilii be, as it is likely to be, divided,
it may be tied with ease. This was the me-
thod adopted by Mott in the operation, in
which he tied the primitive iliac artery ; a case
which sufficiently establishes the adequacy of
this plan for the high ligature of the vessel, at
the same time that it displays in a strong light
the difficulties for which the operator must be
prepared. In such cases the method of di-
viding the internal oblique and transversalis
used by Mott may be adopted with advantage,
viz. after having opened the fascia transversalis
to insinuate the finger between it and the peri-
toneum, and guided by it to divide both mus-
cles at once from within. It must not be
forgotten that it is not uncommon to find the
ureter crossing the internal iliac artery, upon
the right side, near its origin.

Operations for the ligature of the internal
iliac artery. — The method adopted in this
operation by Stevens, by whom the artery was
first tied, and that recommended by the ma-
jority of writers, is similar in principle to the
first plan of Abernethy for the external iliac,
and differs from it only in the length of the
incision, which, according to Guthrie, should
be five inches, beginning about half an inch
above Poupart's ligament and about the same
distance to the outside of the inner ring; it
should be nearly parallel to the course of the
epigastric artery, but a little more to the out-
side, in order to avoid it and the spermatic
cord, and have a gradual inclination inwards
toward the external edge of the rectus muscle :
according to Hodgson the centre of it should
be nearly opposite the superior anterior spinous
process of the ilium. The aponeurosis of the
external oblique, and the internal oblique and
tranversalis muscles having been divided with
the same precautions to avoid the peritoneum,
as in the other case, the fascia transversalis is
to be torn through at the lower and outer part,
so that the fingers may be passed outward

towards the ilium, and the peritoneum detached
from the iliac fossa, and turned with its contents
inward by a gradual and sidelong movement of
the fore and second finger inwards and upwards,
until passing over the psoas muscle the ex-
ternal iliac artery is discovered by its pulsation.
This is then to be traced upward and inward
toward the spine, where the origin of it and
the internal iliac from the common iliac trunk
will be felt. The artery is to be traced down-
ward from its origin and separated with care
from its connections, and more especially the
vein. The sides of the wound should now be
separated and kept apart with curved spatulae
in order that the surgeon may, if possible,
see the artery, and have sufficient space for
passing the ligature. Great care must be taken t
to avoid every thing but the artery ; the peri-
toneum which covers, and the ureter, which
crosses it, must be particularly kept in mind ;
the latter may be separated with ease, and
usually accompanies the former as it is being
detached from the artery. The situation of the
external iliac artery and vein, which have been
crossed to reach it, must be always recollected,
and, if possible, they should be kept out of
the way and guarded by the finger of an
assistant.* This method has in this case a
recommendation, which it does not possess for
the other itiacs, viz. that, as it is necessary in
tying the internal iliac to descend more or less
into the pelvis, it is desirable that the external
wound should be as near as possible to the
aperture of the cavity, but the danger to the
peritoneum must be even greater because of
the greater extent to which it must be separated,
and the closer attachment of it to the ten-
dinous than the muscular structure of the
abdominal wall. It, therefore, seems to me a
question whether even in this case the line of
incision here recommended should be adopted,
and whether it would not be better to have
recourse to that either of Roux or Cooper.
Of the two perhaps the former may be best
adapted to the internal iliac for the reason just
assigned ; though, if the inferior extremity of
the incision be not carried beyond the middle
of Poupart's ligament, difficulty must be ex-
perienced in exposing the vessel and passing
the ligature; therefore here again I am dis-
posed to prefer the semilunar line of Cooper,
only not brought so close to the crural arch as
for the external iliac, and prolonged, as di-
rected by Velpeau, two inches at its external
extremity.

It is recommended to pass the ligature from
within outward because the internal iliac vein
is posterior to the artery ; this appears to me,
however, not the most judicious plan, by it the
point of the needle must be first carried out-
ward and then forward and inward in order to
pass round the vessel : now the external iliac
vein is immediately external to and crossed by
the artery ; the junction of the two iliac veins
is also external to the artery, and the internal
one, though posterior, is at the same time ra-
ther external to it. In such a case the course

* Guthri* on Diseases of Arteries, p. 371-2.

ILIAC ARTERIES.

84$

to be pursued must be very much influenced
by the convenience of the moment; but it
would seem the better plan, where a choice can
be made, to pass the needle first backward
between the artery and the external iliac vein,
and then inward behind the artery toward the
pelvis, by which plan the veins will be more
surely avoided, and more space will be ob-
tained for seizing the ligature.

In this as well as every operation upon the
iliac arteries, the spermatic vessels must be
kept in mind, inasmuch as they require atten-
tion as much as the ureter ; they are usually,
however, like it, removed with the peritoneum.
Velpeau suggests the possibility of rupturing
the iho-lumbar artery in isolating the internal
iliac, and the risk ought not to be overlooked.

Ligature of the primitive iliac artery. — Any
of the methods recommended, whether for the
internal iliac or the external at a high point,
will answer for the ligature of the primitive
iliac. Guthrie gives the preference to that
upon Abernethy's first plan in this as in the
case of the internal iliac ; but it appears to me
that here, at all events, the method of Roux or
the modification of Cooper's operation is to be
preferred ; for, beside that there does not exist in
this case the reason for approximating the line of
incision to the aperture of the pelvis, which
applies to the internal iliac artery, the situation
of the aneurismal tumour in front must render
the direct line of incision less convenient than
a lateral one, and by the adoption of the for-
mer there must be incurred a great exposure
of the peritoneum without a commensurate
advantage ; the necessity also of stripping the
membrane from all or a great part of the front
of the aneurism, incurred by this plan, must
be very objectionable. The length of incision
recommended by Guthrie is five inches at the
least, and may be required of even greater
extent ; thus Mott was obliged to extend it in
his case upward and backward, about half an
inch within the ilium, to eight inches : he
adopted the principle of Cooper, commencing
his first incision "just above the external ab-
dominal ring, and carrying; it in a semicircular
direction half an inch above Poupart's liga-
ment until it terminated a little beyond the
anterior superior spinous process of the ilium,
making it in extent about five inches." It is
likely that a longer incision may be necessary
in this method when applied to the primitive
iliac than in that recommended by Guthrie ;
the greater length of the external incision is
doubtless an objection of secondary impor-
tance; but it is probable that, when the pri-
mitive artery is to be tied, little will be gained
by commencing the incision so low as was
done by Mott, and that it would be more ad-
vantageous to carry it upward rather than
downward ; such appears to have been the
design of Crampton in the operation per-
formed by him for the ligature of the primitive
iliac, in which the line of incision was curved,
concave toward the umbilicus, and extended
from the anterior extremity of the last rib down-
ward beyond the superior anterior spinous
process of the ilium, and since unnecessary

VOL. II.

division of the abdominal parietes is of course
to be avoided, and the leaving them entire at
the lower part must be attended with two good
results, viz. avoidance of the aneurism and less
subsequent danger of pecuniary protrusion,
I cannot but regard this plan as a desirable
addition to the methods of proceeding when
the primitive iliac is the vessel to be tied.
In passing the ligature the difference of the
relation between the vein and artery of the
opposite sides is to be borne in mind, the
former being external to the artery on the right
and internal on the left, on both sides however
being upon a posterior plane.

The obstruction to the course of the opera-
tion caused by the protrusion of the viscera is
to be expected ; in that of Mott it is described
as very great, while no mention is made of it
in Crampton's. This difference was probably
the consequence of the difference in the site
of the wounds. The separation of the artery
and vein is more easily effected than in the case
of the external ihacs, because their investment
is less thick and resisting.

The diversity presented by the arteries of
the opposite sides suggests a difference as to
greater practicability and probability of success
on one as compared with the other ; the artery
of the right side being longer than the left
presents greater room for the application of a
ligature at a sufficient distance, whether from
the seat of the disease or from the origin of the
vessel, while that of the left being more per-
pendicular in its course and nearer to the left
side of the body ought to be more easily ex-
posed ; but it is to be recollected that this dis-
position is not uniformly present.

Before undertaking an operation upon any
of the iliac arteries it will be advantageous to
determine, so far as possible, the relation of
the vessel, which is to be the subject of it, to the
superficial points of the abdominal wall. This
must be understood to be intended only as an
approximation, but by attention to the follow-
ing circumstances it will prove sufficiently
close to serve the desired purpose. The mean
point, at which the aorta divides and the pri-
mitive iliac commences, is half an inch below
the umbilicus at its left side, and that at which
the external iliac terminates is midway between
the symphysis pubis and the superior anterior
spinous process of the ilium : of course a line
connecting these points will define the general
course of the primitive and external iliac arte-
ries. The length of the primitive iliac being
from two to three inches, the extent of its
course may be determined by the subdivision
of this line. The point of demarcation be-
tween the primitive and external iliacs, and
which will serve to mark the origin of the in-
ternal and external, as well as the termination
of the primitive, may be further determined by
a line extending from the crest of the ilium
about one inch and a half behind its anterior
superior spinous process to a similar point on
the other side; such a line will traverse the
sacro-vertebral articulation posterior to the di-
vision of the primitive iliac, and by its decus-
sation with that before mentioned will mark

3 K

650

ARTERIA INNOMINATA.

more particularly the point of division of the
vessel,* which will also correspond nearly to the
centre of a line drawn from the anterior superior
spinous process of the ilium to the umbilicus.f

The practicability and success of these ope-
rations have been so long established that they
do not now require to be insisted upon.

When the external iliac has been tied below
the origin of the epigastric and circumflex ilii
branches, the circulation of the limb is main-
tained through the communications of the
branches of the internal iliac with those of the
femoral, of which the principal have been
ascertained by Sir A. Cooper]: to be the gluteal
with the external circumflex, the obturator with
the internal circumflex, and the ischiatic with the
profunda, and through those of the circumflex
iliac with the same. (See FEMORAL ARTERY.)
When the ligature has been applied above the
origin of these branches, the circulation is esta-
blished also through their communications with
the internal iliac, the internal mammary, the
inferior intercostal and lumbar arteries.

The ligature of the internal iliac artery can
cause little interruption of the supply of blood
to the parts to which it is distributed ; its com-
munications are so numerous and free, exter-
nally and inferiorly with the external iliac and
femoral arteries ; inward with that of the other
side, and upward with the aorta through the
middle sacral and hemorrhoidal arteries, that
the obstruction of the main trunk can affect it
but little.

When the primitive iliac has been tied the
circulation must be restored by means of the
communication which exists between the arte-
ries of the upper and lower extremities through
the internal mammary and epigastric arteries,
of that between the aorta and the iliac arteries,
through the intercostal, lumbar, middle sacral,
hemorrhoidal, and the branches of the latter, and
of that between the iliac arteries of both sides.

For BIBLIOGRAPHY, see ANATOMY and ARTERY.
( B. Alcock.)

ARTERIA INNOMINATA, (in human
anatomy) Fr. Tronc brachio-ccphalique.

The innominata or brachio-cephalic artery is
situated to the anterior and right side of the
thorax, extending from the arch of the aorta to
the sterno-clavicular articulation.

Of the three large vessels proceeding from
the arch of the aorta, the innominata is the
most anterior, the shortest, but of the largest
calibre ; it takes its origin at a point corres-
ponding and very nearly parallel to, the upper
edge of the cartilage of the second rib almost
immediately from that part of the arch of the
aorta where it alters its direction from the right
towards the left side, or rather from the com-
mencement of what is termed the transverse
portion of the arch, and hence the cause of its
being at this point not only to the right side
but also anterior and rather superior to the
other two, which arise from the remainder of

* Guthrie.

t Harrison.

t Medico-Chirurgical Transactions, vol. iv.

the transverse division of the arch, the left
carotid and subclavian arteries. It imme-
diately ascends obliquely upwards, outwards,
and very slightly backwards, to opposite the
right sterno-clavicular articulation, where it
divides into the right sub-clavian and carotid
arteries, the latter of which, although the smal-
lest in diameter, appears from direction to be
its continuation. The innominata, therefore,
is but a short trunk, rarely exceeding from an
inch and a half to two inches in length. Ne-
vertheless instances are upon record in which
it has attained above two inches and a half;
but these may be considered more in the light
of anomalies than regular occurrences.

We now proceed to consider the various re-
lations which this vessel bears to the several
important organs in its neighbourhood, and we
shall then the more readily be able to account
for the many distressing symptoms usually
accompanying its enlargement. At its origin,
it lies upon the trachea and at its division cor-
responds, although at a considerable distance,
to the longus colli muscle separated from it by
glands and cellular tissue. Internally, or on
its left side from below upwards, are the com-
mencement of the left carotid artery and the
trachea, the latter, however, lying upon a plane
posterior to the artery, a quantity of cellular
tissue and glands being usually met with
between them. Externally or to its right
the relations are more complicated and consist
of parts of very great importance. It is here
connected to the right pleura and the middle
and inferior cardiac branches of the great sym-
pathetic nerve; the internal jugular vein lies
above it and on its right side, whilst the right
brachio-cephalic vein is to its right but some-
what anterior. Behind this vein and crossing
the subclavian artery at right angles very close
to its origin, we find the pneumo-gastric nerve
entering the thorax and giving back its recur-
rent branch which winds round the subclavian
artery; still more externally is the phrenic
nerve conducted into the thorax upon the an-
terior border of the anterior scalenus muscle,
and between the two latter the internal mam-
mary branch of the subclavian artery. The
parts covering the vessel are studied with
greatest advantage from the integuments back-
wards ; and the best method of effecting this is
as follows, as it enables us at the same time to
take a clear view of the attachment of the
various layers of the cervical fascia to the first
bone of the sternum and the inter-clavicular
ligament.

Having placed the subject with a block
underneath the shoulders, and the head hanging
down, thus drawing the vessel as much as
possible out of the thorax, carry an incision
of about five inches upwards, commencing at
the middle of the sternum opposite the carti-
lage of the second rib. Through this incision
carry another of the same length at right angles,
commencing at the left sterno-clavicular arti-
culation, and extending along the right clavicle
as far as its centre. This crucial incision
should merely divide the skin, the triangular
flaps of which are next to be raised and re-

ARTERIA INNOMINATA.

fleeted to the right and left, thus exposing a
layer of fascia separating the skin from the
platisma muscle ; this fascia is thin externally,
but where it corresponds to the interval between
the two sterno-mastoid muscles it becomes
dense and more or less loaded with fat ; reflect
this fascia and the platisma will next appear,
behind which is that usually described as the
superficial fascia of the neck covering the
sterno-mastoid muscle, containing the external
jugular vein, and increasing considerably in
density above the sternum, over which it passes
down in front of the pectoral muscles. Like
the previous layer its thickness is augmented
by fat. If this be raised the sterno-mastoid
muscles and the first layer of the deep cervical
fascia, extending between their two anterior
margins, are brought into view, together with
some small superficial vessels and nerves.
This latter fascia should be carefully examined
above the sternum to the anterior margin of
which it strongly adheres ; it is very dense, so
much so that if we endeavour to force a finger
into the thorax at this point, it effectually resists
our efforts. Behind this fascia is a space cor-
responding in depth to the thickness of the
upper edge of the first bone of the sternum,
containing fat and usually a gland, and in ad-
dition a vein rather larger than a crow-quill,
extending across the neck about half an inch
above the sternum ; this communicates with a
vein on either side of the neck running down
on the anterior margin of the sterno-mastoid
muscle, and should be carefully avoided by
the surgeon in the operation for tying the in-
nominata, as it is of sufficient size to cause
embarrassment if wounded. If the fat and
gland be now removed we come down upon
the second layer of this fascia, which is also
very dense and adheres to the inter-clavicular
ligament. Having examined these parts and
the triangular space existing between the sternal
and clavicular insertions of the sterno-mastoid
muscles, the sternal insertions of the latter
should be detached and the first bone of the
sternum removed ; this will expose the remains
of the thymus gland and the sterno-hyoid and
thyroid muscles, which being cut through and
reflected upwards are found to cover the deep
or third layer of the cervical fascia, which
may be traced from the anterior scalenus
muscle to its union with its fellow of the op-
posite side, binding down the cervical vessels,
&c. Upon removing this fascia we come down
upon the arteria innominata covered by the
following parts ; inferiorly the left brachio-
cephalic vein passes nearly horizontally across
the root of the artery to form the vena cava
superior by uniting with the corresponding
vein of the right side. Although the com-
mencement of the vena cava, strictly speaking,
has a closer relation to the arch of the aorta than
the innominata, it is nevertheless sufficiently
near the latter to render it of considerable im-
portance in operations performed upon that
vessel. Superiorly the first or upper cardiac
nerve in its course towards the thorax crosses
the innominata opposite its bifurcation ; we
next observe the right inferior thyroid vein,

851

which, emanating from the lower portion of
the thyroid gland, and having formed with its
fellow of the opposite side the thyroid venous
plexus runs, obliquely downwards from the
gland towards the right side directly in front
of the innominata artery, and empties itself
into the vena cava superior between the two
brachio-cephalic veins. The middle thyroid
artery, when it exists, may now be seen ascend-
ing in front of the trachea. These several
objects, viz. the left brachio-cephalic and thy-
roid veins with the cardiac nerve, are all en-
veloped in a quantity of loose cellular tissue
and glands serving to connect them to the
vessel, which may now be fully exposed and
its different relations studied; when we shall
observe that on its right side there is a space
bounded superiorly by the right subclavian
artery, inferiorly by the left brachio-cephalic
vein, to the right by the right brachio-cephalic
vein, and to the left by the innominata artery
itself; this is the situation where the aneurismal
needle should be introduced in the operation
for tying this vessel, as we thus run less risk of
wounding the veins.

From the above description it is evident that
the coverings of the innominata may be ar-
ranged into ten layers, which, enumerated from
the surface, consist of

1. The skin. 2. Layer of superficial fascia.
3. Platisma myoides muscle. 4. Superficial
fascia. 5. First bone of the sternum, sternal ex-
tremity of the right clavicle, sterno-mastoid
muscle, with its accompanying vein the sterno
and inter-clavicular ligaments and anterior layer
of deep cervical fascia. 6. Cellular tissue, fat,
containing large vein and a gland ; the second
layer of deep cervical fascia. 7. Sterno-hyoid
muscle. 8. Sterno-thyroid muscle. 9. Third
layer of deep cervical fascia. 10. Cellular
tissue containing the first cardiac nerve, right
inferior thyroid, and left brachio-cephalic veins,
glands, &c.

Arrived opposite to the right sterno-clavicu-
lar articulation and to the interval between the
sternal and clavicular insertions of the sterno-
mastoid muscle, the arteria innominata usually
divides into the right carotid and subclavian.
arteries. It rarely gives off any branches ante-
cedent to its division, but a small third branch
is frequently observed proceeding from it to
distribute itself in front of the trachea, and ter-
minate in the thyroid gland. Mr. Harrison,
in his work on the Surgical Anatomy of the
Arteries, has named it the " middle thyroid
artery." The French anatomists give M.
Neubauer the credit of discovering it, and
consequently term it " 1'artere thyroid ienne de
Neubauer " It is, however, as frequently given
off from the aorta between the arteria inno-
minata and left carotid.

When we consider the relation which the in-
nominata bears to the important organs sur-
rounding it, we can scarcely be at any loss to
account for the apparently remote symptoms
present in aneurism of this vessel; such, for
instance, as oedema and blueness of the upper
extremities, head and neck, cough, difficulty
of breathing and swallowing, vertigo, failure
3 K 2

852

ARTERIA INNOMINATA.

of sight, &c. Where the tumor extends to-
wards the right side it presses upon the light
brachio-cephalic vein, preventing the return of
blood from the right arm and side of the head
and neck; if upwards in that direction the
carotid and subclavian arteries become im-
plicated, and consequent interruption to the
circulation ensues; if forwards, the passage
of blood is stopped through the left brachio-
cephalic vein and the inferior thyroid venous
plexus ; if to the left, it encroaches upon the
left carotid artery and trachea, whilst by en-
larging backwards it acts immediately upon the
trachea and mediately upon the oesophagus.

Although the above facts are interesting, as
serving to elucidate the various phenomena
occurring in this malady, I fear that we must
not attach too much importance to them as
means of diagnosis, inasmuch as many, if not
all, of the above symptoms may result from
enlargement of other vessels and other causes,
indeed we have only to turn to the admirable
work of Mr. Allan Burns on the Surgical Ana-
tomy of the Head and Neck, to be at once aware
of the probability of deception in this respect.

Anomalies. — There are perhaps few arteries
in the body which present so many varieties
and anomalies as the innominata, whether stu-

died

respect to its extent, course, situ-

ation, or the number of branches which it gives
off. In the first place, it is frequently met
with extending up into the neck as high as
the thyroid cartilage before it divides into its
ultimate branches, and sometimes lying in
front of the trachea. It is scarcely necessary
to remark in how great a degree this anomaly
increases the difficulties and dangers attending
the operation of tracheotomy. Secondly, the
most remarkable variety occurring in the course
of this artery is described by M. Velpeau, who,
in his Ele"mens de Mcdecine Operatoire, men-
tions three instances in which it passed to the
left side in front of the trachea, and subse-
quently wound from before backwards over
this organ, returning between the oesophagus
and vertebral column, to its usual points of
division opposite the right sterno-clavicular
articulation. Thirdly, the innominata is also
occasionally irregular as to situation. It has
been found arising from the centre of the trans-
verse portion of the arch of the aorta instead
of its commencement, and dividing into right
and left carotid arteries, the right subclavian
taking its origin from the spot usually occupied
by the innominata. Again, instead of being
placed on the right it has been met with given
off from the left or posterior part of the arch
dividing into the right and left carotids and left
gubclavian, in other instances into left sub-
clavian and left carotid. Cases are also on
record in which the innominata was altogether
absent, the right carotid and subclavian arte-
ries arising directly from the arch of the aorta.
Fourthly, it is frequently anomalous in the
number of branches it gives off. Occasionally
the left carotid arises from it in addition to its
usual branches, sometimes it divides into the
two carotids instead of the subclavian and
carotid; and Tiwlemann mentions an instance

where it gave off the right internal mam-*
mary.

The considerations of the functions, size, and
situation of the innominata,as well as its relations
not only to the heart and aorta but also to the
surrounding parts,at all times rendered the study
of this vessel a subject of interest and impor-
tance in the eyes of the operative surgeon ; but
it is comparatively of later years since Mr.
Allan Burns first directed the attention of the
profession to the fact that circulation through
this vessel might be suddenly arrested without
the functions of the brain, and power of the
superior extremity being of necessity de-
stroyed, that surgeons have been found bold
enough to attempt placing a ligature upon it.

There are three cases upon record in which a
ligature has been placed upon the trunk of the
innominata itself. The first operation was per-
formed by Professor Mott, of New York, on
the llth of May, 1818. The patient died on
the 26th day after the operation from repeated
hemorrhage resulting from ulceration and yield-
ing of the vessel.

The second was by Professor Graeff on the
5th of March, 1829. The patient died on the
sixty-seventh day after the operation from re-
peated hemorrhage.

The third was by Mr. Lizars at the Edin-
burgh Royal Infirmary, on the 31st of May,.
1837. The patient died on the twenty-first day
after the operation, likewise from hemorrhage.

This artery was likewise tied by Mr. Bland on
the 25th March. 1832. The patient died on the
13th of April, three weeks after the operation.

The following are the steps of the operation.
The patient being placed in the horizontal po-
sition with the shoulders raised and the head
thrown back, make an incision of about two-
inches upwards along the anterior margin of
the sterno-cleido-mastoid muscle of the right
side, commencing at the upper edge of the
sternum : from the inferior extremity of this-
carry another of similar extent outwards upon
the right clavicle; these should divide the skin
and subcutaneous tissue : next dissect this flap
from below upwards and reflect it, exposing the
platisma muscle ; cut through this muscle and
the superficial fascia beneath it, and then care-
fully detach the sternal insertion of the sterno-
mastoid muscle and anterior layer of deep
fascia, and should there not be sufficient space
a portion of the clavicular fibres of the muscle.
Having proceeded thus far, cut through the
second layer of deep fascia, avoiding the vein
already described as crossing this space, and
subsequently divide the sterno-hyoid and thy-
roid muscles upon a director; this will expose
the third layer of deep fascia covering the
vessel; a portion of this should be pinched up
by forceps and an opening veiy cautiously
made in it, after which, with the handle of a
scalpel, clear the artery of its surrounding cel-
lular tissue, draw the thyroid veins to the left
side, the right pneumo-gastric nerve and in-
ternal jugular vein to the right, and pressing
the left brachio-cephalic vein downwards, carry
the ligature obliquely upwards and inwards,
or from the right to the left side, keeping it

v INSECTA.

853

close to the vessel to avoid implicating the
cardiac nerves.

Other plans of operation have been recom-
mended, but the above appears to me to be the
best, as it gives the surgeon room and oppor-
tunity to see the state of parts through which
he cuts, and enables him, if necessary, to tie
either the subclavian or carotid, or both, with-
out further trouble or inconvenience.

It has been recommended to remove a por-
tion of the first bone of the sternum ; but the
idea will scarcely be entertained by any sur-
geon possessing a proper knowledge of the parts,
or who is competent to perform the operation.

In the year 1827 Mr. Wardrop introduced
a new method for treating aneurisms of the
innominata in imitation of Brasdor's plan of
tying the vessel beyond the aneurismal tumour.
He tied the subclavian artery, having found that
the circulation through the carotid was very
weak if not quite obliterated.

The patient was a Mrs. Denmark. The
results of this case have been recorded as fa-
vourable, but erroneously so. Mrs. Denmark
died in the year 1829 of the same malady on
account of which she underwent the operation.
Altogether his example has been followed in
six cases, with various results.

In the first, Mr. Evans, of Belper in Derby-
shire, in the year 1828, tied the carotid for
aneurism of the innominata and commence-
ment of the carotid. The patient recovered.

In the second, M. Dupuytren, on the 12th
of June, 1829, tied the subclavian for aneu-
rism of the innominata. The patient died nine
days afterwards.

In the third, Professor Mott tied the carotid
for aneurism of the innominata on the 26th of
September, 1829. The patient recovered.

In the fourth, Dr. Hall, of Baltimore, tied
the carotid for aneurism of the innominata on
the 7th of September, 1830. The patient died
five days afterwards.

In the fifth, M. Morrisson, of Buenos Ayres,
tied the common carotid for aneurism of the
innominata on the 8th of November, 1832.
The patient died twenty months afterwards.

In the last, Mr. Fearn, of Derby, tied the
carotid for the same complaint in the year 1836,
the circulation through the subclavian being
almost obliterated. Subsequent to the ope-
ration the patient suffered from repeated at-
tacks of bronchitis, with difficulty of breath-
ing and cough upon the slightest exertion,
so much so that on the 26th of July, 1838,
she was again placed under Mr. Fearn's care.
That gentleman concluding, after a careful ex-
amination, that, in consequence of the circu-
lation having been renewed through the sub-
clavian artery, the previous operation had not
cured the aneurism (which he now found im-
plicated the commencement of the subclavian
artery) determined upon placing a ligature
upon this vessel where it passes over the first
rib, and performed the operation on the 2d of
August, 1838, apparently with complete success.
Here then are the results of the two plans
of operation hitherto performed in connection
with the innominata. In Hunter's all the pa-

tients were lost from repeated hemorrhage,
although, as we have seen in one instance, the
individual survived the operation above two
months. Mr. Pattison, in his account of Mr.
Mott's case, appears to attribute the loss of the
patient to the fact of that gentleman's having
commenced by exposing the subclavian artery,
thereby depriving the vessel of nourishment
by the unnecessary destruction of the vasa
vasorum ; this might in some degree have led
to the result; but I am more inclined to be-
lieve that it occurred from other causes over
which the surgeon unfortunately has no con-
troul, I allude to the situation, origin, and direc-
tion of the vessel itself. We have already ob-
served that it arises from the commencement of
the transverse portion of the arch of the aorta,
and is consequently in a direct line withtheaorto-
ventricular opening, being in point of direction
the continuation of the ascending portion of the
arch of the aorta. It thus receives the undi-
minished impetus bestowed upon the blood by
the contraction of the ventricle at a distance,
barely of three inches ; hence, when a ligature
is placed upon it, the force of the ventricle is
directed more immediately upon this part of
the artery, a coagulum can scarcely, if at all,
be formed here, and the ligature being subjected
to the constant efforts of the blood to overcome
it, instead of ulcerating its way out, cleanly di-
viding the vessels, produces inflammation and
ulceration in its neighbourhood by constant
friction, and thus gives rise to the fatal results.

If I have here taken a correct view of the
causes which have led to the fatal termination
in all the cases where Hunter's method has
been adopted, (and I have no reason to doubt
having done so, as we learn from the accounts
of the post-mortem examinations both in Mott's
and Lizars' cases, that the coagulum was very
imperfectly formed, and that extensive ulcera-
tion of the vessel had ensued in the neighbour-
hood of the ligature,) I am quite justified in
adding that it is an operation which should
never be performed unless in those cases where
it presents the only chance of lengthening the
patient's existence.

This remark, however, does not apply to the
plan introduced by Mr. Wardrop in imitation
of Brasdor. Out of the seven cases in which
it has hitherto been employed, and which I have
here cited, three were successful, and of the
other four one lived for a period of twenty
months, and another (Mrs. Denmark) for about
two years after the operation.

(H. Hancock.)

INSECTA.— (wopa', Fr. Insecte; Germ.
Insecten.) A class of Invertebrate animals,
which, as constituted by Linnaeus, formerly
included several remarkable groups, which
are now arranged as distinct classes. Besides
the true Insecta these were Crustacea, Arach-
nida, and Myriapoda. Modern naturalists
have been almost unanimous in separating
these groups from Insects, which, in their per-
fect state, differ from them in being constantly
Hexapods. Besides this very marked character,
Insects differ from Crustacea in respiring atmo-

854

INSECTA.

spheric air by means of ramified tracheae — from
Arachnida in the body being constantly divided
into a distinct head, thorax, and abdomen —
and from Myriapoda, in the body being com-
posed in general of thirteen segments.

Insects, therefore, may be characterized as
a class of hexapodous invertebrate animals,
which possess antennae, and have the body com-
posed of several segments, united into three
and sometimes four distinct parts, articulated
together, consisting of head, thorax, and abdo-
men. They breathe atmospheric air by means
of lateral spiracles and tracheae., and pass through
a succession of changes of form, or shed their
external covering before they arrive at their
perfect state. They also possess other charac-
ters in common with the Myriapods and Arach-
nidans, as the circulation of the nutritive fluids
by means of a pulsatory dorsal vessel, divided
into distinct chambers or compartments, and
the respiration of atmospheric air by means of
spiracular orifices, and with the Crustaceans in
being in general oviparous.

Anatomically considered, Insects, as re-
marked by Professors Grant* and Owen,f bear
a remarkable analogy amongst invertebrated
animals to Birds amongst the vertebrated. They
constitute the most beautiful, most active, and
most highly organized of any of the Inverte-
brated classes. Like Birds, they are inhabi-
tants of the air, the earth, and the waters, and
the dominion of some of them is even extended
to the bodies of other animals. Physiologically
considered, they also resemble " the feathered
tribes of air." Like them they have a more
voluminous and extensive respiration, and a
greater power of generating and of maintaining
a higher temperature of body than any other
class in the division of animals to which they
respectively belong. The number of species
is greater than is known in any other division
of the animal kingdom, and is only exceeded,
as in Fishes, by the almost countless myriads
of individuals which every species produces.
The metamorphoses which most of them under-
go before they arrive at the perfect state, and
are able to fulfil all the ends of their existence,
are more curious and striking than in any other
class, and in the greater number of species the
same individual differs so materially at its dif-
ferent periods of life, both in its internal as
well as external conformation, in its habits,
locality, and kind of food, that it becomes one
of the most interesting investigations of the
physiologist to ascertain the manner in which
these changes are effected, — to trace the suc-
cessive steps by which that despised and almost
unnoticed larva that but a few days before was
grovelling on the earth, with its internal organi-
zation fitted only for the reception and assimila-
tion of the grossest vegetable matter, has had
the whole of its external form so completely
changed as now to have become an object of
admiration and delight, and able to " spurn
the dull earth" and wing its way into the open
atmosphere, with its internal parts adapted only

* Lectures on Comp. Anatomy, Lancet. 1833-34.
, «__ • ' • p. 246. '

for the reception of the purest and most con-
centrated aliment, now rendered absolutely
necessary for the support and renovation of its
redoubled energies. But this condition of
insect life is greatly modified in the different
families. Thus the most active species are
diurnal insects, and are those which have the
greatest development of the organs of locomo-
tion, accompanied, as in birds of flight, by a
more voluminous respiration, and a greater
force and rapidity of circulation, and consequent
muscular energy and necessity for a constant
supply of food, as is well exemplified in the
hive-bee and its affinities. But although many
species are furnished with wings for flight, these
organs are not universally met with in the
species of every order, neither are they con-
stant in the two sexes of the same species. In
these instances it is always the male individual
that is furnished with them. These exceptions
occur among the beetles, as in the glow-worm
(Lampyris, Jig. 335 & 336), in the Blatta
or cock-roaches (jig. 343), in some species of
of moths (Bombycidf), and in the plant-lice
(Aphides), while in other species, the ants, the
individuals are furnished with wings only at a
particular season of the year, and lose them
immediately after the fulfilment of certain
natural functions. In each of these instances,
as noticed by Mr. Owen* in the ostrich and
other birds unaccustomed to flight, the extent
to which the respiratory organs are developed is
in proportion to the habits of the species, being-
greatest in those of flight and least in those
which reside constantly on the ground. Indeed,
so varied are the forms, so different the habits
and modes of life, that the division of Insects
into families and tribes has afforded no small
amount of difficulty to the scientific naturalist
in arranging them according to their most natu-
ral affinities, and hence a great variety of sys-
tems have been proposed for this purpose, all
of which perhaps are open to many objections.
But it is not in the mere division of Insects
into families and tribes that the philosophic
naturalist meets with the greatest difficulty, but
in assigning the situation which the whole
class ought to occupy in the animal kingdom,
both in regard to Insects themselves, and in
their relations to other animals. Whether
naturalists adopt as the basis of arrangement
the development and perfection of the nervous
system or that of the skeleton, with the organs
of circulation and digestion, as compared with
similar parts in other classes, they have usually
been led to admit that while Insects are superior
to many groups, which have been placed above
them, in the former respects, they are inferior to
them in the latter; and hence, although that
portion of the animal body which is so all-
important to active existence, the nervous
system, is employed without hesitation as the
fundamental type and principle of arrangement,
and in the vertebrated classes is scarcely ever
departed from, it has become in the hands of
many naturalists only of secondary importance
in the invertebrated, and the greater perfection

* See AVES, vol. i. p. 341.

INSECTA.

855

of the circulatory and digestive organs in the
molluscous classes has induced them to place
these, which in other respects are inferior
in development, above the Articulated. We
cannot, however, agree with those who consider
the organs of nutrition alone of sufficient im-
portance to allow of this deviation from the
fundamental principle of arrangement, neither
can we admit with others that the nervous
system of the higher Articulata is inferior to
that of the higher Mollusks, the Cephalopoda,
while we ourselves claim for the higher Articu-
lata the most decided superiority in the next
essential character of arrangement — the deve-
lopment of the skeleton and organs of locomo-
tion.

Without entering further upon this difficult
subject, we will simply state our conviction
with Carus, Burmeister, and others, that the
articulated ought to stand at the head of the
invertebrated classes, seeing that they contain
among them some of the most completely
organized of invertebrated animals. We shall
reserve for the present our explanation of the
steps by which we propose to pass from the
lowest vertebrated forms to these, in our esti-
mation, the highest of the invertebrated, and
proceed to consider the arrangement of Insects,
as a class, as proposed by different naturalists,
before we enter upon an examination of the
peculiarities of these animals.

The principles upon which naturalists have
attempted to arrange this interesting class have
been almost as various as the systems proposed.
Aristotle among the ancients arranged Insects
with reference to the presence or absence of
the organs of flight ; and although he was far
more successful than many of his successors in
separating from Insects the Crustacea, as a dis-
tinct class, his arrangement of Insects is not
entirely natural, since it separates some of the
most nearly connected families. Among the
moderns, Aldrovandus, in the beginning of the
seventeenth century, divided them into land and
water Insects, and subdivided these groups into
families according to the structure of their
wings and legs. Swammerdam many years
afterwards first proposed to arrange Insects
with reference to their metamorphoses; first,
those which undergo only a partial or incom-
plete metamorphosis, and, secondly, those which
undergo a true or complete one. The latter he
again divided into those which undergo a slight
change of form, but are active during the pupa
state ; secondly, those which have distinct limbs
but are inactive in that condition ; and, lastly,
those which have no external development of
wings or legs, but remain as inactive ovate
pupae. This was the first step towards arranging
Insects upon a truly natural system ; since, as
Messrs. Kirby and Spence have justly ob-
served,* although the employment of the meta-
morphoses taken alone leads to an artificial
arrangement, it is of the greatest use in con-
nexion with characters taken from the perfect
Insect, in forming a natural system. Our
illustrious countryman Ray, in the beginning

* Introd. to Entomol. vol. iv. p. 442.

of the eighteenth century, followed the example
of Swammerdam in arranging Insects primarily
according to their metamorphoses ; and Lister,
in 1710, followed with a modification of Ray's
classification, after which nothing further was
proposed until Linnseus published the first edi-
tion of his Sy sterna Naturae in 1735. His arrange-
ment was based upon the form and structure of
the wings. By these he divided Insects into three
groups. First, those \vithfpur wings, in which
he included in three divisions those Insects
which now constitute his orders Coleoptera,
Hemiptera, Lepidoptera, Neuroptera, and Hy-
menoptera. In the second group he placed
Insects with two wings, his single order Dip-
tera ; and in the third, Insects without wings,
his order Aptera. In this arrangement, founded
partly upon that of Aristotle, Linnaeus was
particularly successful in establishing some very
natural series, although in including the Crus-
tacea among his Aptera, like Swammerdam
and Ray, he receded a little from a natural
system. After Linnaeus, Degeer and Geoffrey
each proposed a new arrangement, but it was
not until an entirely new set of organs had
been selected by Fabricius that Insects began
to be arranged upon truly natural principles.
The parts from which Fabricius drew his cha-
racters were those of the mouth, by which he
divided Insects primarily into two sections, the
Mandibulated, or those furnished with jaws for
comminuting their food, and the Haustellated,
or those which take their aliment by means of
a flexible elongated proboscis, without distinct
manducatory organs. But the difficulty of
forming a strictly natural system still existed,
so long as the characters employed were derived
only from particular sets of organs, and not
from a consideration of the whole. Cuvier, by
founding his arrangement upon an examination
of all the external organs, and thereby establish-
ing natural families, advanced very far towards
the object desired, and was followed by La-
treille, Lamarck, Dumeril, Leach, Kirby and
Spence, and MacLeay, who continued to im-
prove the arrangement of the class. These have
been followed by Messrs. Stephens and Curtis,
and very recently by Mr. \Vestwood, the inde-
fatigable Secretary of the Entomological Society,
each of whom has proposed a different arrange-
ment. But none of the systems hitherto pro-
posed are entirely satisfactory, so great indeed
is the difficulty of discovering the connecting
links of families, which, distributed over the
whole globe, are believed to include from
100,000 to 150,000 distinct species; and this
difficulty will probably continue until the in-
ternal as well as the external organization is
better known in a greater number of insects
than it is at present, and applied to their
arrangement, as has lately been done by Bur-
meister. In the succeeding pages we shall
adopt the arrangement of Mr. Stephens, giving
a synoptical view of the families, with the
addition of some of the recently established
foreign ones, and shall also add particular
descriptions of some of the most remarkable,
referring our readers for more minute descrip-
tions of them to Mr. Stephens's admirable

856

INSECTA.

" ^lustrations/' and also to the valuable work by Mr. Westwood, from wliich work we shall
" An Introduction to the Modern Classifica- in part derive the characters by which the
tion of Insects," now in course of publication different tribes are distinguished.

Table of the Arrangement of Insects according to the System of Mr. Stephens.

CLASS INSECTA.

SUB-CLASS I.
MANDIBULATA.

COLEOPTERA.

Pentamera.

"

"Cicindelidae Tiger-beetles.

Sub-tribe 1.
Geodephaga.
Predaceous
ground-feeders.

Brachinidae
Scaritidae
CarabidjE, fig. 329, Ground-beetles,
Harpalidse
Bembidiidae

Tribe 1.
Adephaga.

^Elaphridae

C Gluttons.)

Sub-tribe 2. -\

Hydradephaga. 9 Diticidae Water-beetles.

Predaceous ^Gyrinidae Whirlgigs.

.

water-feeders. 3

.£ j

"Heteroceridse

s

CO

Parniidae

" Sub-tribe 3.

Limniidae

Phylhydrida. ^
Water-lovers.

Helophoridae
Hydrophilidae,^. 330, Water-beetles.

Sphaeridiidse

Tribe 2.

Anisotomidae

Rypophaga. •<

(Cleansers.)

"Scaphididae

Silphidae, fig. 331, Carrion-beetles.

Sub-tribe 4.

Nitidulidae

Necrophaga.

Engidae

Carrion-feeders.

Paussidse, West.

^

_Dermestidae

Pentamera.

Helocera 1.

Lamellicornes 2.

Byrrhidoe Sand-beetles.
Histeridae Dung-beetles.

'Lucanid83 Stag-beetles.

Scarabaeidae

Geotrupidas, fig. 332, Dung-beetles.

Aphodiidae

Trogidaa

Rutelidae
Anaplognathidae
Melolonthidae Cockchaffers.
Glaphyridae
Cetoniadae Sun-beetles.

Subsectio 3.
Macros terni,

Sternoxi. Lat.
(pointed sternum).

Sub-sectio 4.
Aprosterni, West.
Malacodermi,
(soft skin.)

~) Buprestidae Got
VEucnemidse, West.
\ Elateridae,^g.334, Springing beetles.

rCebrionidae
' Cyphonidae

Lampyridse^s.SSSSt 336 Glow-worms

Telephoridae
, Melyridae
1 Tillidae

Ptinidae
I Lyinexylonidye

L' BostricicUe
Scolytidae

Death-watches.
Wood-borer i>.

INSECTA.

857

Pseudo-

f Curculionidie fig. 337 Ho

Tetramera,

llhincbophora 1. < Altelabidoe, We*t.

Wat.

(. Salpingrdae

\

CO

o

r

f Cucujida;
) Prionida1 fis. 338 Goat-bt
Long.cornes. Sub-sect.o a. 4 CemmbydJa

v.Lepturidae

^ Eupoda 1. Crioceridae

Phvtophaga, ^
KJRBY. ) rGalerucidae
V. Cyclica 2. < Chrysomelidae/g. 339
(.Cassidae Helmet-beetles.

COLEOPTERA.

Pseudo-trimera
West.

^ / f Coccinellidae Lady-Cows.
'X ( Trimeri 3. •£ Endomychidas
1 ) {.HispidjE

r

"Tenebrionidae

Blapsidae^. 340

Pimelidae

Helopidae

Lagriidae, West.

*i

Melandryidae

Hetero-mera

..2 J J Horiidce, West.

11

Mordellidae

GQ

(Edemeridae

Pyrochroidae

Cantharidae Oil-beetles.

Notoxidae

I

^Scydmanidae

Brachelytra.

DERMAPTERA.

ORTIIOPTERA.

NEVROPTERA.

NEUROPTERA.

Panorpina 1.
Anisoptera 2.
Libellulina 3.

Temitina 4.
- Megaloptera 5.

fPselaphidae "}

I Tachyporidae

1 Staphylinidae Jig. 341 ^Rove-beetles.
I Stenidae

'

TRICIIOPTEKA.

Forficulidae Earwigs.

'Gryllidae Grasshoppers.
Locustidas Locusts.
Achetidae fg. 342 Crickets.
Phasraadae

Mantidae, Praying Insects.
_Blattida3 Jig. 343 Cock-roaches.

$ Boreidae

I Panorpidae fg. 344 Scorpion- flies.

Ephemeridae fg. 345 May-flies.

{ Agnonidas

i Libellulidae, Dragon-flies.

("Myrmeleonidae Lion-ants.

! Ilemerobidae

\ PsocidiE

I Raphidiidc

I Mantispidae, West.

LTermetidae, White Ants.

5 Sialida-
I Perhdae

f Philopotamidae

•? Leptoceridae

C Phrygaindae Caddis-JHen.

858

INSECTA.

HYMENOPTERA.

HYMENOPTERA.

STREPSIPTERA.

LEPIDOPTERA.

DlPTERA.

Terebrantia 1

Pupophaga 2.

Aculeata 3.

f TenthredinidiTe./%. 355 B. Saw-flies.
< Xiphydriidae
V. Uroceridae

f Evaniidaa

j Ichneumonidas Ichneumon-flies.

I Braconidae

vAlysiidae

rFormicidoe Ants.

Mutillidae

Scoliidae

Sapygidae

Pompilidae Sand-wasps.

Sphecidae
I Larridae
i Bembecidae
I Crabronidae

Vespidae Jig. 346 Hornets
I Apidae Bees.

Andrenidae Sand-bees.

Wasps.

Tubulifera 4.

f Chrysididae Golden wasps.
) Chalcidid32
^ Proctotrupidae
(.Cynipidae Gall-flies.

Stylopidae fig. 347

SUB-CLASS 2.
HAUSTELLATA.

Papilionidse

Diurna 1.
Crepuscularia 2.

Pomeridiana 3.

Nocturna 4.
Semidiurna 5.

Vespertina 6.

Hepialidae -\

Notodontidae f ., ,.

)Bombycid32 >Moths.

vArctiidae J

^ Lithosiidae
i Noctuidae

f Geometridae
< Platyptericidoe
CPyralidae

f Tortricidae
j Ypuonomeutidae
"i Tineidaa
vAlucitidae

f"Culicid33 Gnats.
• Tipulidae Long-legs.

Asilidae fig. 349

Empidas

Dolichopidae

Rhagionidae

Mydasidae

Tabanida3 Blood-suckers.

INSECTA.

DIPTERA (contin.)

HOMALOPTERA.

APHANIPTERA.
APTERA.

HEMJPTERA.

"Terrestria 1.

^Aquatica 2.

HOMOPTERA.

CLASS INSECTA, (Insects.)
Animal Invertebrated, hexapodous, under-
goes metamorphoses.

Body in general winged, and composed of seg-
ments divided into three distinct regions.
Skeleton external, formed of the dermal co-
verings.

Antenna two, respiration aerial, sexes distinct.
Sub-class 1. MANDIBULATA.

Order I. COLEOPTERA.

Wings four, anterior ones (elytra) hard, co-
riaceous, covering the abdomen, divided by a
longitudinal suture, not employed in flight;
posterior ones usually jointed, with their apex
acute. Metamorphosis complete.

The Beetles constitute by far the most nu-
merous and varied tribes in any order, and
differ as much in habits and size as in general
form. They include every variety of confor-
mation and bulk from the minute but rapa-
cious Staphylinidte, to the gigantic phytopha-
gous Dynastida and Cetoniidtf. So numerous
are the species that, according to Burmeister,*
there are 28,000 in the Berlin collection alone,
while the whole that is known is supposed to
exceed 36,000. In Mr. Stephens's arrange-
ment they have been divided into families
which amount to more than one-third of the
whole class, and these families are grouped
into six sections. The first section includes
most of the predaceous beetles, and is divided

* Manual of Entomology (Translation), p. 583.

859

fAnthracidse
Acroceridje
Stratiomydae
Xylophagidae
Syrphidae
I Stoinoxydae
Conopidae
(Estndae Gad-flies.
(jVluscidae House-flies, fyc.

{ Hippoboscidae fig. 350 Forest-flies.
\ Nycteribidae

Pulicidae Fleas.

$ Pediculidae, Lice.

i Nirmidae/g. 351 Bird-lice.

.-Cimicidae Bugs.

J Pentatomidae

\ Coreidae

] Reduviidae Masked bugs.

1 Acanthiidae

^•Hydrometridae Skip-jacks.

Nepidae fig. 352 Water-scorpions.
Notonectidae Water-boatmen.

/-Cicadiidae fig. 353 Tree-hoppers.

Cercopidae
j Psyllidae
] Thripidse
1 Aphidae Plant-lice.
^-Coccidae

into two tribes, Adephaga and

and these are divided into four sub-tribes.

The first sub-tribe, Geodephaga, includes the
predaceous Ground-beetles, which are cha-
racterized by the elegance of their form and
alacrity of their movements. They have six
projecting palpi,* their mandibles are strong,
curved, and pointed, and their legs slender
and formed for running, (fig. 329.) Some of

Fig. 329.

Carabus moruUs, ( Ground-beetle, male.)

* The third pair of palpi are maxillary, and are
the analogues of what we shall hereafter describe
as the Galca.

860

INSECTA.

this division, the Cicindeli&e, are extremely
voracious, and most of them feed upon dead
animal substances, although some of the Har-
pulid<E are known to be vegetable feeders.
The second sub-tribe, Hydradephaga, includes
the predaceous water-beetles, and the third,
Philhydrida, a variety of families allied to
each other by similarity in general structure,
by inhabiting water or damp situations, and by
subsisting upon decaying animal and vegetable
substances, fungi, &c. Amongst the aquatic
species is one of the largest British beetles,
Hydrous piceus (Jig. 330).

Fig. 330.

Hydrous piceus, ( Great water-beetle, male.)

All the water-beetles are characterized by their
four posterior legs being formed peculiarly for
swimming ; they are ciliated along the tarsal
joints, the last of which is furnished with a
very minute claw. The insects of the third
sub-tribe, the predaceous water-beetles, Dyti-
cid<z, are distinguished from those of the second
by the latter having long and slender instead
of clavated antennae, and by their possessing
six instead of only four palpi. The males of
both sub-tribes have one or more joints of their
anterior tarsi (jig. 330, A.) very much dilated,
by means of which they attach themselves
strongly to the females. Their larvae are active

Fig. 331.

and voracious. The fourth sub-tribe, Necro-
phaga, includes the carrion and burying-beetles
(Jig. 331), so called from their habit of bury-
ing small dead animals in the ground, by
digging away the earth from beneath them,
and thus allowing them to sink down, and
then depositing their eggs in the bodies. The
genera of this division differ considerably from
each other, but may be characterized as in
general possessing abruptly clavated antennae,
an oval or oblong body, with the elytra often
truncated, and the legs strong and formed for
running.

The second section is also divided into four
tribes, which include insects of different habits
and conformation.

In the first tribe, Helocerti, the insects are
of an oval shape, and have the antennae geni-
culated, and terminated by an oval club.
Their legs are flattened, broad, and formed for
burrowing, and are terminated by very minute
tarsi. Their bodies are exceedingly hard ; they
feed upon decaying animal matter, and when
touched simulate the appearance of death.

The second tribe, Lamellicornes, are a very
natural group. They are distinguished by the
club of the antennae being divided into plates
or lamellae. Their legs are thick, strong, and
deeply notched, and the tarsi of the anterior
pair in some families are very minute. They
are either stercoraceous or vegetable feeders,
subsisting, like the common dung-beetle, Geo-
trupes stercorarius* (Jig. 332), upon decom-

Fig. 332.

Necrophorus vespillo, ( Burying-beetle}.

Geotrupes stercorarius, (Dung-beetle).

posing vegetable substances, or like the chaffer-
beetles, Melolonthida, upon the foliage of
shrubs or trees, or like the Dynastid<s^

* This drawing is of a specimen captured by the
writer of the present article in the summer of 1829,
and affords a curious instance of malformation of
the anterior extremities with the tibiae lunated and
acuminated, without dentations, the tarsi entirely
wanting. It is now in the cabinet of the Rev. F.
W. Hope.

t It is asserted that the Dynastes Hercules grasps

INSECTA.

861

(fig. 333) upon the sap that flows from the
wounded bark or roots.

Fig. 333.

The third tribe, Macrosterni, WESTW. in-
cludes a family of insects, Elateridz, (fig. 334),

Fig. 334.

Dynastes Herculet.

f the ppicranium ; b, theclypeus; e, labrum; d,
mandibles- e, maxilla and palpi \f, labial palpi;
q, antennae; /«, the eye; ». prothorax and horn;
It, scutellnm ; I, elytra ; TO, abdomen; n, femur;
o, tibia ; p, the tarsus ; q, unguis.

Elater nocttiucus, (Click beetle, female.) West-Indian
Jire-beetle.

or springing-beetles, which are commonly
known in their state of larvae, as the wire-worm^
and are often exceedingly injurious to meadows
and Corn-fields. In some counties many acres
of meadow-land have occasionally been de-
stroyed by these insects attacking the roots of
the grass, which then quickly perishes.* They
are characterized in their perfect state by having
an elongated body, with the head sunk deeply
into a notch in the prothorax ; by their fan-shaped
•or serrated antenna?, and by a long spine or pro-
cess directed backwards from the pro-sternum or
under-surface of the prothorax, and received
into a groove in the meso-sternum. By means
of this spine they are enabled, on bending the
body and then suddenly retracting it, to spring
to a considerable distance. From this act they
have derived their name. Some species of the
family are remarkable for shining brilliantly at
night, and are the noted fire- flies of the West
Indies.

In the fourth tribe, Aprosterni, WESTW.,
there are insects equally curious and destruc-
tive as in the preceding. The true Aprosterni
are distinguished chiefly by their soft flexible
elytra, by an entire absence of any process
from the sternal surface of the prothorax, and
by the dilatation of the margins of the pro-

the branch of a tree between its frontal (a) and
thoracic horn (i), and then whirls itself round to
cut through the bark and occasion a flow of sap,
upon which the insect is said to subsist. Impro-
bable as the statement appears, from the circum-
stance that the thoracic horn is wanting in the
female, we were once assured of its correctness,
by a gentleman who affirmed to us he had witnessed
the fact. A similar act is attributed to the male
stag-beetle, Lucanus cervus, which is furnished with
mandibles nearly half the length of its whole body,
while in the female they are not larger than in other
insects of the same size.

* The Rev. F. W. Hope has ascertained that the
larvae of this family were exceedingly destructive
to the potato crops in the West of England during
the summer of 1838, an account of which was
read at the meeting of the Entomological Society,
April 1st, 1839.

862

INSECTA.

thorax, which anteriorly covers the base of the
head. Some exceptions exist to these charac-
ters in the Bostricidte and their congeners,
which ought perhaps to be removed to another
tribe. In the Lampyrida (glow-worms), (Jigs.
335 and 336), there is an example of a circum-

Fig. 337.

Fig. 335.

Fig. 336.

Male. Female.

Lampyris noctiluca, (Glow-worm).

stance not uncommon among insects, the pos-
session of wings by the male sex and their
entire absence in the female. The Ptinidtz or
death-watches, and other Xylophagous insects
of this tribe, although small, are exceedingly
destructive to furniture and the wood of houses;
and the Bostricidte and Scolytida to living trees.
It is an insect of this family, Scolytu* de-
structor, that of late years has occasioned in-
calculable mischief to the elms in St. James's
Park and Kensington Gardens, and in the
park at Brussels. So lately as the summer of
1836 nearly eighty fine elms were cut down at
the latter place and its neighbourhood, in con-
sequence of decay occasioned by this pest.*
Another species S. pygmaus, which attacks
the oak, has destroyed many thousands of
young trees in the Bois de Vincennes.-\- Ano-
ther genus, Tomicus typographies, was so de-
structive in the Hartz Forest in Germany du-
ring a series of years from the beginning of the
last century to 1783, that the number of trees
destroyed by it in that forest alone was calcu-
lated at a million and a half.J

In the third section, Pseudo-tetramera,
WESTW., the species have one false and four dis-
tinct tarsal joints to their legs, with pulvilli or
hairy cushion on their under surface, and the
ante-penultimate joint is bilobed and broader
than the others. The section is divided into two
tribes.

In the first tribe, Rhynchophora, (Jig. 337),
the head is elongated in the form of a snout or
rostrum, at the extremity of which is the mouth,
and at the sides are inserted the antennae which
are usually geniculated and club-shaped. The
larvae of these insects are generally apodal,
and many species are exceedingly injurious to
the blossoms of the apple, pear, and other
fruit-trees. Both the larva and perfect indi-
vidual of one minute species, well known as
the " weevil." Calandra granaria, closely al-
lied to Jig. 337, occasion immense losses in
the storehouses of the factor by attacking and
destroying his corn. The parent insect not

* Trans. Ent. Society, vol. ii. p. xvi.

t Annal. Soc. Ent. France. 1836, pp. xvi. and
xxx. 1837, p. iv.

| Latreille, Hist. Nat. torn. ii. Gmelin, Ab-
hand. iiber die Wurmtroekniss. Leipz. 1787. West-
wood, Introduction, &c. vol. i. p. 352.

Calandra longipes, male.

only feeds upon the corn itself, but deposits a

single egg in every grain, and the larva when

hatched devours the whole excepting the husk.

The second tribe, Longicornes, (Jig. 338),

Fig. 338.

Cerambyx latipes.

are known chiefly by the great length of the
antennae, which usually exceeds that of the
whole body. Their mandibles are strong and
pointed ; the body elongated and depressed ;
and the prothorax, which is often tuberculated
or spined, is narrower than the abdomen.
Their larvae are short, thick, and apodal, and
are furnished with strong mandibles, and live
beneath the bark or in the wood of trees.

The third tribe, Phytophaga, KIRBY, is also
composed of pseudo-tetramerous insects, with
pulvilli on their tarsi, and is divided into two
sub-tribes. In the first, Eupoda, the body is
of an elongated oval form, the head is sunk
deeply into a narrow prothorax, and the thighs
of the posterior legs are greatly enlarged. In
the second sub-tribe, Cyclica, the body is of a
rounded or oblong oval (Jig. 339), the base
of the prothorax is narrower than that of the
elytra, and the antennae, which are of moderate
length, are inserted widely apart from each

INSECT A.

863

Fig. 339.

form, are never terminated by a pectinated club.
It includes many genera of dissimilar habits,
the darkling-beetles, Blapsida, the meal-bee-
tles, Tenebrionida, and the Cantharida, the
oil-beetles and blister-flies.

In the sixth section, Brachelytra, (fig- 341 ),

fig. 341.

Timarcha tenebricosa.

other. It is an insect of this tribe, Hallica
nemorum, that often occasions so much injury
to the agriculturist by destroying his crops of
turnips immediately after the young plant ap-
pears above ground. The perfect beetle,
scarcely larger than a millet-seed, deposits its
eggs upon the under surface of the first leaves,
and the larva when hatched penetrates into the
substance of the parenchymatous tissue, be-
tween the cuticle of the upper and under sur-
face of the leaf, where it lives until it is ready
to undergo its transformations in the ground.*
In some years the plants are attacked by such
prodigious numbers of these insects that many
thousand of acres are destroyed in a few days.
The loss sustained by the devastations of this
insect in Devonshire in 1786, is said to have
been not less than £100,000 f

In the fourth section, Pseudo-trimera, WEST.
the insects have only three distinct joints in
their tarsi, although a fourth one, exceedingly
minute, and which like the additional one in
theTetramera was first noticed by Messrs. Kirby
and Spence,t exists at the articulation of the last
joint, as in the insects of the third section. The
Pseudo-trimera are distinguished by their tarsi,
by their oval or hemispheric shape, and by the
antennae ending in a three-jointed club. The
larvae are hexapodous and active ; those of the
common lady-cow, Coccinella, feed upon
aphides, and other genera upon fungi.

In the fifth section, Heteromera, there are
five joints in the first and second pairs of legs,
but only four in the third, (jig. 340). The
palpi, four in number, are large and projecting,
and the antennae, usually filiform or monili-

Fig. 340.

Blaps mortisaga, (Darkling-beetle).

* Le Keux, Trans. Ent. Society, vol. ii. p. 24.
t Kirby and Spence, Introduce, to Entom. vol. i.
p. 185.
J Id. vol. iii. p. 683, 4.

Creophilus marillosiu, (Rove-beetle).

the body is elongated, and terminated by two
exsertile papillae, the elytra short, quadrate,
and often covering only the meso- and meta-
thorax ; the true or posterior wings, folded be-
neath the elytra; head broad and flattened,
mandibles large, hooked, and pointed, antennae
often enlarged towards their extremities, and
the tarsi of all the legs five-jointed. The
larvae are active and voracious, and undergo a
complete metamorphosis.

The situation assigned to this group of in-
sects by different systematists has varied con-
siderably. Many authors have placed them
with the pentamerous insects, unto which from
their habits and number of joints in their tarsi
they appear to belong. Thus Dejean assigned
them a position between the Hydradephaga
and Phylhydrida ; Dr. Leach* between the
Silphida and Dermestid<e ; Mr. Kirby, in his
recent work,t between the Adephaga and
Necrophaga; and, lastly, Mr. Westwood J
between the Dermestida and ByrrAujfe On
the other hand Mr. Stephens, after Linne" and
Fabricius, has placed them at the end of his
Coleoptera, thinking, probably, as Mr. Kirby
has remarked, that they are connected with the
following orders, Dermaptera and Orthoptera,
by their abbreviated elytra, and by their anal
papillae or styles ; as they are also, probably,
by the shortness and structure of their alimen-
tary canal, which in many respects as much
resembles that of the ForfculieUe or Bfettufe,
as the Adephaga or Necrophaga.

Order II. DERMAPTERA.

Wings four, anterior ones (elytra) crustace-
ous, quadrate, and divided by a straight suture ;
not employed in flight ; posterior ones mem-
branous, folded longitudinally and transversely,
only partially covered by the elytra; anus
armed with large moveable forceps. Larva
active, resembles the perfect insect. Metamor-
phosis incomplete.

The single family of this order, Forficulidtf,
(Earwigs) are readily distinguished from the

* Article Entomology, Edin. Encycl. vol. ix.

f Insects, Fauna Boreali -Americana, p. 85 et
seq. 1837.

\ Introduc. to the Modern Classification of In-
sects, &c. 1838-9.

864

INSECTA.

Brachelytra by the forcipated anus, the great
length of the antennae, and the breadth and
circularity of the wings when expanded, com-
pared with the narrow and acute ones of the
latter insects.

Order III. ORTHOPTERA.

Wings four, anterior ones coriaceous, reticu-
lated, and overlapping each other, posterior
ones partly coriaceous partly membranous, re-
ticulated, and folded longitudinally; head ver-
tical ; mandibles, thick, strong, and dentated ;
palpi four, maxillary ones in most genera five-
jointed. Metamorphosis incomplete. The larvae
are active, and resemble the perfect insect.

In this Order are included many remarkable
families. The Locustidic, Locusts ; the Ache-
tida, the House and Mole-crickets (jig. 342) ;

Fig. 342.

Gryllotalpa vulgaris, (male). Mole-cricket.

the Mantida, or praying insects ; and the Blat-
tid# (fig. 343), or destructive Cock-roaches.

Order IV. NEUROPTERA.

Wings four, linear, naked, membranaceous,
and minutely reticulated ; all employed in
flight; head large, eyes projecting; body linear.

This Order is divided into five sections.

In the first section, Panorpina, or Scorpion-
flies (Jig. 344), the head is produced anteriorly

Fig. 344.

Panorpa commtinis (male). Scorpion-fly.
(Samouelle.)

into a short rostrum, at the extremity of which
is the mouth, as in some of the Curculionida ;
the antenna,' are long and filiform, and the
body is slender, and terminates in the female
in an acute ovipositor, and in the male in an
articulated claw (a) like the tail of the Scor-
pion, from which the insect derives its name.
The larva is unknown, but is supposed to un-
dergo a complete metamorphosis. The pupa
or nymph is inactive.* The perfect insect is
predaceous.

In the second section, the Anisoptera or Ephe-
merida, May-flies (Jig. 345), are distinguished

Fig. 345.

Elatta Ori'Htali* (male.) The Cock-roach.

Ephemera vulgata. May-fly. (Samoudle.)

by the smallness of their posterior wings, by the
shortness of the antennae, and by the long setae
at the extremity of the abdomen. The larvae
are active, and much resemble the perfect in-
sect. They reside constantly beneath stones,
or in burrows at the bottom of running streams,f
and undergo an incomplete metamorphosis.
The pupa is active like the larva. In the per-
fect insect, which takes no food, and is prover-
bially noted for the shortness of its existence,
which is seldom more than a few hours, the
parts of the mouth are almost entirely oblite-
rated.

In the third section, Libellullna, Dragon -
flies, all the wings are of equal size, eyes large
arid prominent, antennae minute, body slender,

* Westwood, Introduction to Entomology, vol.
ii. p. 53.

t Ibid. vol. ii. p. 29.

INSECTA.

865

and tarsi with only three joints. The larva
and pupa are active, voracious, and aquatic, and
like those of the Ephemera, resemble the per-
fect insect. Metamorphosis incomplete.

The fourth section, Termitina, have large
and nearly equal sized wings, either disposed
horizontally or erect, with the antennae rather
long and filiform, as in Hemerobid<e, lace-
winged flies, or club-shaped, as in the ant-lions,
jMyrmelionidtf. The larvae are active and pre-
daceous. The ant-lion lives at the bottom of a
minute pit-fall, which it digs to entrap other
insects. The Hemerobius lives among crowds
of Aphides, plant-lice, upon which it feeds,
while the larvae of the Termites, or white ants,
live in societies of almost innumerable indivi-
duals. The first two of these families undergo
a complete metamorphosis, and the insects in
the condition of nymphs are inactive in the
earlier stages of the pupa state. In the latter
family the larva and pupa greatly resemble the
perfect insect, and are active at every period of
existence.

The fifth section, Megaloptera, have the pos-
terior wings rather larger than the anterior, the
head and pro-thorax large and quadrate, and
the antennae long and setaceous. Metamor-
phosis incomplete. According to Mr. West-
wood * the larva and pupa are active, and not
inclosed in a case, are aquatic, and greatly re-
semble the perfect insect.

Order V. TRICHOPTERA.

Wings four, deflexed, hairy, not reticulated ;
texture slightly coriaceous ; posterior pair pli-
cated, broader than the anterior; antennae very
long, setaceous ; ocelli three ; maxillary palpi
long ; " mouth unfitted for mastication ; man-
dibles rudimental." Metamorphosis complete.

The perfect insects of this Order, called by
fishermen " stone-flies," f are found on water-
plants, stems of trees, and palings by the side
of rivers. The larvae, the caddis, or case-worms,
are aquatic, and reside in little cases which
they carry about with them, and construct by
uniting bits of wood, minute shells, and frag-
ments of stones, which are woven together with
threads of fine silk. The pupa is semi-com-
plete, and quiescent during the greater part of
its period, but becomes active, and creeps out
of the water upon the stems of plants before
changing to the perfect insect.

Order VI. HYMENOPTERA.

Wings four, membranous with large areolar
cells ; posterior pair smaller than the anterior ;
antennae longer than the head ; eyes large ;
ocelli three. Mandibles strong, and generally
dentated ; maxillae largely developed ; labium
and ligula together forming a long proboscis
sheathed by the maxillae. Female armed either
with a borer or sting. Metamorphosis com-
plete.

This Order is divided into four sections.

In the first, Terebrantia, borers, the abdo-
men is sessile or united to the thorax by its

* Introdnct. to Entom. vol. ii. p. 23.
t Yarrell's British Fishes, vol. ii. p. 84.

VOL. II.

whole breadth. In one family, the saw-flies,
(fig. 355, B), the abdomen is armed with two
serrated partially concealed plates, with which
the insect cuts through the bark or pierces the
leaves of plants to deposit her eggs. In ano-
ther family, Urocerida, the true borers, the ab-
domen is armed with a strong projecting cylin-
drical spiculum, which is grooved on its under
surface, and contains two smaller dentated spi-
cula, analogous to the plates of the saw-fly,
with which the insect bores into timber-
trees and deposits its eggs. The larvae are
active and extremely voracious. Those of the
saw-flies, pseudo-caterpillars (jig. 355, A,) de-
vour the leaves of plants, and are sometimes
exceedingly injurious to the agriculturist, as
has been the case with those of Athalia centi-
folia to the turnip crops during the last few
summers,* while the larvae of Urocerida are said
to be equally destructive to living trees.f

In the second section, Pupophaga, the ich-
neumon flies, the body is long and slender, and
the abdomen is petiolated, or connected only
by a constricted neck with the thorax, and the
antennae are long and setaceous. The larvae are
apodal, and are parasitic on other insects.

In the third section, Aculeata, the body is
short and pedunculated, and furnished with a
true aculeus, which is used as a weapon of de-
fence. The larvae are apodal, are fed by the
parent or by sterile females, and generally re-
side in cells. Some species are solitary, and
feed their young with the bodies of other in-
sects, CrabronidcE ; others live in society, and
are either omnivorous, as the Formicida, ants,
and Vespida, hornets (fig. 346) and wasps, or

Fig. 346.

Vetpacrabro. The Hornet. (SamoueUe.)

mellivorous, as the humble and hive bees,
(Apida), which feed their young upon a mix-
ture of pollen and honey.

In the fourth section, Tubulifera, the body
is short, slightly convex, and often compressed
laterally; the posterior wings are almost en-
tirely destitute of nervures, and the abdomen is

* Prize Essay of the Entomological Society on
the Anatomy, Habits, and Economy of Athalia
centifolia, 1838, by G. Newport.

t West wood, Introd. &c. vol. ii. p. 119. Mr.
Ruddon in Trans. Entomological Society, vol. i.
p. Ixxxv.

3 L

866

INSECTA.

furnished either with a telescopic, jointed tube,
as in the Chrysidida, golden wasps, or with a
spiculiferous ovipositor, which is partly retrac-
tile within the abdomen, as in the Cynipidee,
gall-flies. The former of these insects deposit
their eggs either in the cells of other Hymen-
optera or in the bodies of active Lepidopterous
larvae, before their change to the pupa state, and
thus resemble in habits the true Ichneumonida.
The Cynipida puncture the leaves or bark of
trees and plants, and deposit their eggs, at the
same time injecting into the wound a fluid
which occasions the growth of galls or excre-
scences, the interior of which is both food and
habitation for the young larva. In their habits,
as Mr. Westwood has well observed, the Cyni-
pid& very closely approach the Terebrantia,
and seem to form a link of communication be-
tween them and the true Ichneumonidts.

Order VII. STREPSIPTERA.

Wings four, the anterior ones (pseudelytra)
very minute, twisted, and projecting trans-
versely from the sides of the meso-thorax like
little scales ; posterior pair very large, fan-
shaped, with radiating nervures, and plicated
when folded. Body linear, abdomen com-
pressed, metathorax very large; meso- and pro-
thorax very short; head transverse, broader
than the pro-thorax; eyes slightly peduncu-
lated; antennae inserted into an exca-
vation in the front, and terminated by two
branches; mouth unfitted for taking food;
maxillae minute, projecting, stiliform ; labial
palpi very large.* Metamorphosis complete.

These insects, Stylopidee, are parasitic and
exceedingly minute ; they undergo their trans-
formations in the bodies of perfect wasps and
bees, and pass out between the abdominal seg-
ment. Latreille has aptly designated them the
CEstri of insects. It is entirely unknown where
the eggs are deposited, whether in the body of
the wasp or bee, or in that of its larva. Four
distinct genera of these minute parasites have
already been discovered. Stylops Spencii (Jig.
347) is one of the largest species, but is scarcely

Fig. 347.

.

Stylops Spencii, highly magnified.
Westwood, Ent. Trans.

* Kirby in Lin. Trans, vol. xi. p. 86.
and Spence, Introduct. vol. iv. p. 378.

Kirby

more than two lines in length, while the small-
est species yet known, Elenchus Templetonii,
WEST.* is not more than two-thirds of a line,
or scarcely a line in breadth with its wings ex-
panded.

The anomalous structure of these insects has
been a matter of great difficulty to entomolo-
gists. Rossi, who first discovered an insect of
this order, placed it with the Hymenoptera.
Mr. Kirby at first thought that it ought to follow
the Coleoptera, on account of its elytra and
kind of metamorphosis ; Mr. Mac Leayf placed
it between the Coleoptera and Hymenoptera,
to both of which, as Mr. Kirby had remarked,
it is connected by its metamorphosis. Dr.
Leach placed it between the Coleoptera and
Dermaptera, while Mr. Newman, who at first
thought it belonged to Hymenoptera,:}; afterwards
placed it with the Diptera,§ between which
two Orders it was also placed by M. Samo-
uelle.|| It has, however, been satisfactorily
shown by Mr. Westwood 11 that it is an imper-
fectly mandibulated insect, and that if the
structure of its oral apparatus, the shortness of
its first thoracic segments, and its kind of me-
tamorphosis be considered, it ought to be
placed between the Hymenoptera and Lepi-
doptera, at the end of the Mandibulata, which
situation it occupies in Mr. Stephens's arrange-
ment.** But the existence of elytra, and the
peculiar structure of its wings, ought not to be
disregarded, and should any species sufficiently
large for minute dissection be hereafter disco-
vered, it is not improbable that an examination
of its internal organs may lead to a different
opinion.

SUB-CLASS II. HAUSTELLATA.

Order VIII. LEPIDOPTERA.

Wings four, covered with minute scales;
mouth proboscidal, formed of two elongated
organs, approximated laterally to form a tube ;
when at rest spirally convoluted. Labial palpi
large, hairy. Metamorphosis complete.

The Order is divided into six sections.

First the Diurna, day-fliers or butterflies, are
distinguished by their long clavated antennae,
which in a few are also slightly hooked at the
apex. The wings are large and erect when the
insect is at rest. The larva or caterpillar has
sixteen feet. Pupa quiescent and complete.

In the second section, Crepuscularia, (Jig.
348,) the sphinges or hawk-moths, the antennae
are prismatic, and generally thickest in the mid-
dle, the body large, and tapering towards its ex-
tremity, which is often bearded, and the wings
are elongated and slightly deflexed when at rest.
The pupa is smooth, and inclosed in a coccoon,

* Westwood, Transact. Ent. Society, vol. i.
p. 169.

t Horae Entomolog. p. 371.

| Mag. Natur. Histor. No. 23.

6 Ent. Mag. vol. ii. p. 326.

\\ Entomol. Compendium, 1819, p. 288.

fl Trans. Ent. Society, vol. i. p. 169 et 172.
* This is also the place assigned to it by Mr.
Westwood. " Introduction," &c. vol. ii. p. 287.
June 1, 1839.

INSKCTA.

867

Fig. 348.

Fig. 349.

Deilephila elpenor, the Elephant Sphinx.

or in a cell of the earth. The perfect insects
fly very swiftly, and are mostly abroad at
twilight.

In the third section, Pomeridiana, which
includes the silkworm-moths, the body is short
and thick, proboscis in general very short,
antennae tapering, and much pectinated or
feathered in the males, and the wings, when at
rest, deflexed and horizontal. The larva before
changing incloses itself in a case, which in the
T$ombycid(E is composed entirely of fine silk.

In the fourth section, Nocturna, night-moths,
the antennae are setaceous, the proboscis long
and spirally convoluted, the palpi compressed
and terminated abruptly by a minute joint, and
the wings, when at rest, folded horizontally upon
the abdomen. It is a larva of this section,
Agrotis segetum, that of late years has been
almost as injurious to the agriculturist by attack-
ing the full-grown turnip as that of the saw-
fly, Athalia, or the beetle, Haltica, by attack-
ing the plant in the earliest stages of its growth.

In the fifth section, Semidiurna, the body is
slender, the antennas in general setaceous, the
proboscis short, and the wings broad and ex-
panded horizontally, as in the Geometridte, or
deflexed and forming an angle with the body as
in the Pyralidte.

The sixth section, Vespertina, is composed
of minute species, among which are the de-
structive clothes-moths, Tineida.

Order IX. DIPTERA.

Wings two, membranous, naked, and si-
tuated anteriorly to two minute pedunculated
bodies (halteres), the analogues of the pos-
terior wings in the preceding orders ; * meso-
ihorax very large, and forming nearly the whole
of the thoracic region ; head rounded, distinct
from the thorax ; mouth rostriform ; metamor-
phosis complete ; pupa coarctate.

Among the families of this extensive order
are the Cuticu&r, gnats, the Asilid<e (Jig. 349)
and Tabanida, bloodsuckers, the (Estrida,
gad-flies, and Muscida, common house-flies.
In most of the families the larvae are active and

* Kiiby and Spence, Introduction, &c., vol. ii.
p. 354.

Asilus crabroniformis (Samouelle).

apodal, or are furnished only with abdominal
feet. It is doubtful whether any of them cast
their skins during their growth. In most species
it becomes the outer covering of the pupa.

Order X. HOMALOPTERA.

Wings two, or entirely absent ; head sunk
into the anterior part of the thorax, or divided
from it only by a suture ; abdomen flat, broad,
and obtuse ; anus notched ; claws large, biden-
tate or tridentate ; metamorphosis complete :
pupa coarctate.

In this remarkable order, the forest-flies (fig.
350) and ticks, the larva is nourished, and un-

Fig. 350.

Hippobosca eqiuna, the Forest-fly (Samouelle).

dergoes its change into the pupa state within the
abdomen of the parent, as was first noticed by
Reaumur, by whom they were designated " spi-
der-flies." Soon after the pupa is deposited, it
becomes greatly enlarged, and equals in size the
body of the parent. Reaumur found that its
outer envelope or case is formed of the skin of
the larva, as in the true Diptera, and he also
succeeded in detecting within it the proper
covering of the nymph. The type of the order,
the forest-fly (fig. 350) is exceedingly trouble-
some to horses in the summer, and abounds in
the New Forest in Hampshire.

Order XI. APHANIPTERA.

Wings none ; body oval, compressed ; head
small, rounded, and compressed ; eyes simple,
orbicular; thighs strong; posterior legs the
longest ; tarsi five-jointed.

The Pulicidtfy fleas, undergo a complete
metamorphosis. The larva is an active elon-
gated worm, which spins itself a case or coc-
coon, in which it becomes a nymph, and at
the end of a few days assumes the perfect
state. One species, Pulex penetrans, is ex-
ceedingly troublesome in the West Indies by
introducing itself beneath the toe-nails or under
the skin, where it occasions malignant ulcers.
Most of the species are of diminutive size, and
seldom exceed a line in length. Mr. Kirby,
3 L 2

8C8

INSECTA.

however, has recently described one species,
P. Gigas* which is two lines in length.

Order XII. APTERA.

Wings none ; body ovate, flattened ; head
distinct from the thoracic segments, which are
narrower than those of the abdomen ; mouth
either haustellated or mandibulated ; metamor-
phosis incomplete.

This order, which is formed of the Pediculi
of Linnaeus, and is based upon the entire
absence of the wings and an incomplete meta-
morphosis, affords a striking proof that we
ought not in our arrangements to place too
much dependance upon the presence or ab-
sence of any one particular set of organs, or
kind of metamorphosis ; else, as well remarked
by Burmeister, we ought to include among the
Aptera the female Blatta and the common
Cimex, insects which evidently belong to
different orders. But it may be further ob-
served that dissimilarity in the structure of one
particular kind of organs is not alone sufficient
to authorise the separation of genera which in
other respects are closely united ; otherwise
the Ninnida (Jig. 351) ought to be separated

Fig. 351.

Nirmus, the Bird-louse.

from the Pediculid*, although resembling them
in every thing excepting the structure of the
mouth, the very part of the animal upon which
the two great divisions of insects in the present
arrangement is founded.

Order XIII. HEMIPTERA.

Wings four, anterior ones partly leathery,
partly membranaceous, decussating each other
at the apex; posterior wings entirely mem-
branaceous ; pro-thorax and scutellum very
large ; mouth rostriform, composed of elon-

Fig. 352.

gated setae; ocelli three; metamorphosis in-
complete.

This order is divided into two sections, Ter-
restria and Aquutica.

The larva and pupa are active, and most
species subsist upon the juices of other ani-
mals. The Terrestria are distinguished chiefly
by the length of the antennae, which exceeds
that of the head, and by their three-jointed
tarsi. The Aquatica have the antennae in
general shorter than the head (which in some
species (jig. 352) is sunk into the pro-thorax),
the eyes are large, the rostrum short, and the
tarsi with only two joints.

Order XIV. HOMOPTERA.

Wings four, anterior pair either entirely
coriaceous or membranaceous, not decussating
each other ; pro-thorax very short ; head large
and transverse ; antennae shorter than the head
in most genera; abdomen in some furnished
with a compound serrated ovipositor ; meta-
morphosis incomplete.

This order is considered by many authors as
only a section of the preceding. It is, how-
ever, composed of several distinct families.
The types of the order, the Cicadiidce (Jig.
353), tree-hoppers, in possessing a serrated

Fig. 353.

Nepa chierea, the Water-.scorpion (Samouelle).
* Fauna Boreali-Americana, 1837, p. 318.

Cicada h&matodes (female). (Samouelle).

ovipositor seem to approach to the Terebrantia,
while the Thripida, which in the structure of
the mouth resemble mandibulated insects, have
recently been formed into a distinct order,*
and have been placed by Mr. Westwood before
the Neuroptera. Perhaps a closer examination
of the remaining families, Aphida and Coccida,
the plant-lice, &c., might lead to a similar
removal.

In the preceding remarks we have closely
adhered to the arrangement proposed by Mr.
Stephens, but it cannot be denied that much
remains to be done before the entomologist will
be able to form an arrangement so far natural
as to be free from serious objections. The
principal divisions of the last two orders, in
possessing ocelli, in the size of the thorax, the
connexion of the wings during flight (which
we shall hereafter show exists in some of the
Cercopiidff,) and in the serrated terebral ovi-
positor, seem to be more nearly connected
with the Hymenoptera than with the wingless
and less perfectly developed Aphaniptera and
Aptera.

From the above remarks on the orders it will

* Thysanoptera. Haliday, in Entom. Magazine,
vol. iii. & iv.

1NSECTA.

869

be seen that a large majority of insects have four
states of existence, — the egg, the larva, the
pupa, and the imago or perfect state. , Until
very lately, it was supposed that this peculiarity
of existing at different periods under such
different forms belonged only to this class of
the Invertebrata, but recent observation,* as
shown in the article CIRRHOPODA, &c.,f has
made it appear that there are other classes
also which undergo metamorphoses, although
in no instances do the animals continue so long
in their preparatory states, nor undergo such
remarkable changes of form in passing from
one state to another, as insects.

The egg. — In the egg, or earliest stage of
extra-uterine existence, the insect continues for
a longer or shorter time according to external
circumstances. We have at present only to
notice the external form, markings, and colour
of the egg, which vary as greatly in the dif-
ferent species as the locality in which it is
placed by the parent. The greatest variety of
these occurs among the Lepidopterous insects.
In some, as in the butterfly, Pont'ui brassier,
the egg is of an obtuse conical figure, like a
Florence flask, and is beautifully ribbed and
beaded on its exterior surface ; in others, as in
one of the night-moths, Acronycta Psi, it is
ribbed, and is flattened like a lens;J in the
small but beautiful butterfly, Thecla betula,
it is shaped like a turban ;§ in Clisiocawpa
neustria, which glues its eggs together like a
ring around the small branches of fruit-trees,
it is cylindrical, and flattened at both ends,
and in the puss-moth, Cerura vinula, its form
is compressed and lenticular. Among the Neu-
roptera, Hemiptera, and Diptera there are other
forms equally curious. The lace-winged fly,
Chrysopa perla, suspends its egg in the air upon
a long pedicle ;|| the egg of the water-scorpion,
Nepa cinerea (Jig. 352), is encircled at one
extremity by a coronet of rays or processes,1[
while in one of the dung-flies the egg has two
projecting appendages which have somewhat
the appearance of ears. The color and mark-
ings of the egg are not so various as its form.
In the common green grasshopper, Acrida
virUimma, it is green, like the seeds of some
plants. In Pedicia rivosa and Tipula olerucea
it is perfectly black, and in other instances, as
in Odonestis potutoria, it is beautifully en-
circled with bands of white and green, or is
speckled with darker spots, like the eggs
of birds, as in Lassiocampa quercus. The
prevailing colours, however, are yellow, as in
the cylindrical eggs of the oil-beetles, the Meloe
and Proscarabtfi; or white as in the flesh-flies,
Musca vomit oria and domestica ; or perfectly
translucent, as in the saw-fly of the turnip,
Athalia centifblite. The external markings
and sculpture on the egg are not less remark-
able than its general form and colour. Sorne-

* Phil. Trans, part ii, 1835.
t Vol. i. p. 692.
t Sepp.

§ Id. quoted by Burmeister, Manual of Ento-
mology (Trans.), p. 633.

II Reaumur, Kirby and Spence, vol. iii. p. 95.
t Swammerdam Bib. Nat. t. iii. tigs. 7 and 8.

times the egg, as above stated, is ribbed and
beaded, sometimes excavated over its whole
surface into regular cells like a honey-comb,
at others it is imbricated like the tiling of a
house, but in the greater number of instances
it is smooth as in other animals.

These peculiarities of form and color appear
in many instances to" have relation to the cir-
cumstances under which the egg is deposited
by the parent, to its preservation, or to the
locality in which it is placed. The egg of
Scatophaga stercoraria, KIRBY, is only par-
tially inserted into recent cow-dung,* with its
auricular processes, through which it is sup-
posed to respire, exposed to the influence oflight
and air; that of Chrysopa perla, K., the lace-
winged fly, is attached by its pedicle in the
midst of crowds of Aphides, upon which the
young larva is to subsist ;f while the coro-
netted eggs of Nepa (Jig. 352) are inserted into
the stems of water-plants, with their processes
only exposed,]; probably for the purposes of
respiration, until the enclosed germs are stimu-
lated into active existence by the vivifying
influence of light and air, without which
perhaps they would perish. This indeed
happens with the eggs of the great water-
beetle, Hydros piceus (Jig. 330) which, ac-
cording to Lyonet, are deposited in a little nest
that floats upon the surface, and from which
the larvae escape into the water immediately
they are developed. We have found that if
the eggs of this insect be allowed to fall to the
bottom of a vessel of water, and remain there
for some days, organisation proceeds in them
for a day or two, after which they perish. For
a similar purpose the eggs of Athalia centi-
foliff (Jig. 355), which require a high atmos-
pheric temperature for their speedy development,
are inserted into little spaces between the cuticle
and parenchymatous tissue of the leaf of the
turnip. In each of these instances the object
to be insured is the safety of the egg itself;
either its preservation from external injury, or
its full exposure to atmospheric influence to
accelerate its development. It may be re-
marked as a general rule, that those eggs from
which the larvae are most rapidly developed
are those which require the highest tempera-
ture and fullest exposure to the atmosphere.
These are the external circumstances which
greatly influence the development of the germ
into the state of larva.

The larva. — Immediately the insect is liber-
ated from the external coverings of the egg it is
called a larva. It is so designated from its
then being as it were under a mask or in dis-
guise, and unable to fulfil one of the principal
objects of its existence, the continuation of its
kind. In some species, as among the Aptera,
it has at this period the form of the parent,
from which it differs in nothing externally but
size, being always very much smaller. Instances
of this kind occur in the Pediculi and Nirmi
(Jig. 351). In other species, examples of
which are seen in the dm ices, Blattte (fig. 343)>

* Kirby and Spence, vol. iii. p. 97.

t Reaumur, torn. iv. p. 376.

+ Kirby and Spence, vol. iii. p. 95.

870

INSECTA.

Forficul*, and Cicada (Jig. 353), the insect
is very much smaller, but has the general form
of the parent, without any rudiments of wings
or elytra. Another description of larva is that
in which the insect comes from the egg either
as a fat sluggish grub, or as an active and vora-
cious one, with an elongated body very
different in form from that of the parent, and is
furnished with but six legs, which are attached
to the anterior part of the body, in addition in
some instances to two processes employed as
legs at its posterior extremity. Examples of
the last of these occur in the voracious water-
beetles, Dyticidct, in the Carabides or ground-
beetles (Jig. 354) and many others ; and of the

Fig. 354.

Larva of Calosoma Sycophanta ( Burmeister).

first, in the Chaffer-beetles Melolontha, and
stag and dung-beetles, Lucanida and Geotru-
pidce (Jig. 332). Other kinds of larvae, to
which the term is more strictly applicable, are
known to every one, as the caterpillars of
butterflies and moths. These and the pseudo-
caterpillars, the larvae of the saw-flies, Ten-
thredinida, (Jig. 355, A), are active and have

Fig. 355.

A, larva, and B, perfect state of Athalia centifoliae,
the saw-jiy of the turnip, (Newport, Prize Essay. )

elongated bodies furnished, in addition to the
six legs at the anterior part, with many others
along the posterior. They undergo a complete
metamorphosis, both of external and internal
conformation in passing from the larva to the
perfect condition. Besides these there are, as
in the instance of hornets (figs. 356 and 357)
and bees, larvae which are entirely destitute of
organs of locomotion, and exist simply as elon-
gated maggots; and others, as some of the
flesh-flies, Muscat, and the tailed maggots that
inhabit the most noisome puddles, Eristalis
tenax, which are entirely destitute of the true or
anterior legs, and have only those which are
attached to the abdomen.

These kinds of larvae were formerly referred
by Fabricius, under special designations, to

different kinds of metamorphoses, which those
designations were supposed to indicate ; but, as
remarked by Burmeister,* neither were the
terms employed in strict accordance with the
conditions of the larvae themselves, nor always
indicatory of the metamorphoses they were
about to undergo. We fully agree, therefore,
in the opinion expressed by Burmeister, that
the different kinds of larvae are referable to
only two kinds of metamorphoses ; the one a
metamorphosis incompleta, which consists sim-
ply in the insect shedding its skin and
increasing in size, and in some cases acquiring
new organs, but in all stages of its existence
continuing active, and having the form of the
parent, as in the instances above noticed;
and the other a metamorphosis completa, in-
cluding all insects which in the larva state have
a form different from the parent, and undergo
a complete change, both of external and inter-
nal conformation, before they arrive at the per-
fect state.

But whatever be the form or changes of the
insect, the larva state may be looked upon as
its most voracious period of life. In many
species it is also its longest period. Those
which do not hybernate in the perfect state
exist but for a very short time as larvae ; while
those which continue for a long period in the
larva state, as the Lucanida and Melolonthidte,
some of which are said to continue for four
years, pass but a little while in the perfect.
But these periods are not always equally long
in different species of the same families. Thus
among the Apida, the Bombus terrestris, or
common humble-bee, exists but for a short
period in the larva, but a long one in the per-
fect state ; while in a closely allied genus An-
thophora retusa, one of the solitary bees, that
form separate nidi in vertical sections of dry
banks exposed to the sun, the insect often con-
tinues through the whole winter in the larva
state, and only exists for a few weeks of the
following summer in the perfect. On the
other hand the numerous species of Muscidte
exist but a short time as larvae, or maggots, but
a very long time as active flies.

External anatomy of the larva. — The body
of a larva is in general composed of thirteen
distinct segments, or divisions ; the first consti-
tutes the head, with the organs of manducation,
the second, third, and fourth, and, as we shall
hereafter see, in part also the fifth, together
form the thorax of the future Imago, while
the remaining ones form the third division of
the body, the abdomen. In most insects in the
larva state, the whole of these segments from
the second to the thirteenth are equally deve-
loped, and differ but little from each other in
their general appearance. The second, third,
and fourth segments have each a pair of short
scaly feet, the rudiments of the future limbs,
and the segments of the abdomen are often
furnished with soft membranaceous ones, which
disappear entirely when the larva undergoes
its metamorphosis. On each side of the body
there are in general nine oval apertures, the

* Manual, Trans, p. 34.

*pir acute, or breathing holes. These are situ-
ated in the true larva, or caterpillar, in the
second, fifth, sixth, and following segments to
the twelfth. This is the general structure of
the larva, but there are modifications of it in
every particular. Thus, in the larva of those
Hymenopterous insects which are entirely desti-
tute of feet, there are fourteen distinct segments
in the body, besides an anal tubercle, and ten
spiraculae on each side (Jig. 356). These are

INSECTA.

noticed fourteen (Jig. 358).

871
The first four of

Fig. 358.

Fig. 356.

Fig. 357.

Lateral view. Inferior view.

Larva of Vespa crabro, magnified.

situated in the second, third, fourth, and remain-
ing segments to the twelfth, so that in these in-
sects the thoracic portion of the body contains
an additional spiracle, while the abdomen has
one additional segment. This fact is particularly
interesting from the circumstance of its appa-
rently disturbing the opinions hitherto advocated
by naturalists respecting the normal number of
segments, which has been thought to be con-
stantly thirteen in this class of invertebrata, while
it derives a greater importance from theadditional
segment belonging to the abdomen, as we shall
hereafter prove. This additional number of
segments, as constantly occurring in apodal
Hymenoptera, was first pointed out by Mr.
Westwood,* and has been observed by ourselves
in every instance in the larvae of Vespa Crabro,
(fig. 356.) Bombus terrestris, Anthophora
retusa, Ichneumon Atropos, and other species.
In the common maggots or larvae of the flesh-
flies, Muscida, the body is elongated, and
tapering at its anterior extremity, and con-
sists of fourteen segments.t In the larva of a
species of Muse a which infests bacon and other
dried provisions, and in that of the common
flesh-fly, Musca vomitoria, we have distinctly

* Trans. Ent. Soc. vol. ii. p. 124.

t Fifteen, if we include the anterior portion of
the third segment, which appears like a distinct
part. Since these observations have been in print
the XII. and XIII. Parts of Mr. Westwood's " In-
troduction " have been published, and it is grati-
fying to observe that he has found fifteen segments,
including the head, in the larva of Odynerus, Col-
letes, and Anthidium.

A , Apodal larva of Musca ; B, headofdo.: a, mandi-
btilar hooks ; b, the anterior bronchia; c, the labnan ;
C, organs of respiration ; D, a portion of the dorsalvessel.

these appear to constitute the head of the larva,
since in them are contained the palpi and oral
apparatus, besides two remarkable orange-
coloured organs, which project from the sides
of the fourth segment, and on a cursory view
appear to be the organs of vision, but are in
reality the branchiae of the future pro-thorax
(B A). In the larva of the sheep-hot, CEstrus
ovis, which resides for many months in the
frontal sinuses and roots of the horns of that
animal, there are thirteen segments, but the
terminal one is very indistinct, while the an-
terior one, which is exceedingly minute, is
proved to form a large proportion of the head,
by its containing the oral apparatus, and by
the existence in it, at its anterior part, of two
very distinct eyes. These larvae respire by
means of two sets of branchiated organs,
(fig. 358, c) situated at the posterior part
of the body, and not by lateral spiracles.
The apparently anomalous condition of the
head in these insects, like the additional
segment in Hymenoptera, is a circumstance
of much interest, but is not without its
parallel in perfect individuals of other classes,
as in ' Myriapoda, in which the head is most
distinctly composed of at least three seg-
ments. We must not conclude, however, with
Dr. Ratzeburg, as noticed by Mr. West-
wood,* that in Hymenoptera the head of the
Imago corresponds to the first two segments
of the larva, because at the latter period of
the larva state, just before the insect becomes

* Trans. Ent. Soc. vol. ii. p. 125.

872

INSECTA.

a nymph, or pupa, the head is found to occupy
the anterior part of the second segment. The
true head of the hymenopterous larva, before its
changes have commenced, is in reality the
first segment; since, as remarked by Mr.
Westwood, it has not only the usual conforma-
tion of the head, but contains also the rudi-
ments of all the manducatory organs, and the
antennae. In addition to this, we may state
that before the larva has discontinued to feed,
and has begun to prepare itself for transforma-
tion, we have invariably found on dissection,
that the first cerebral mass, the supra-cesopha-
geal ganglion or brain is situated in the superior
part of the first segment, and the first sub-
cesophageal ganglion in the posterior part of the
inferior surface; so that it is not until after
the changes into the nymph state have com-
menced, beneath the skin of the larva, that the
head becomes so greatly enlarged as to en-
croach upon the second segment.

Of the head. The head of a larva, excepting
in Dipterous insects as above noticed, is
usually of a rounded or oval figure, and of a
harder texture than other parts of the body.
At its inferior surface are situated the organs of
manducation, and at its lateral and anterior the
rudiments of the eyes and antennae. In all
true larvae it is divided longitudinally into two
halves, by a suture which extends from the
vertex or epicranium to the face, the front of
which is formed by a convex plate, the clypeus,
or shield (Jig. 359, 6). This is generally of a

Fig. 359.

Head of larva of Athalia centifoliee.
a, the epicranium ;'&, the clypeus ; c, labrum ; d, the
mandibles ; e, maxillae and palpi ; f, [the labium and
labial palpi. (Newport, Prize Essay.)

semicircular, or a quadrangular form, but varies
considerably in different species. Immediately
beneath this plate is situated another, the
labrum or upper lip (c). This also is of an
elongated, quadrangular, and sometimes heart-
shaped form, and constitutes the anterior
boundary of the mouth. Beneath this plate are
a pair of strong horny jaws, mandibula (d),
which are in general'thick, curved, and strongly
indented or toothed, and are placed one on each
side of the head. Beneath these are a pair of
lesser jaws, maxilla (e), placed in a similar
manner, and with the mandibles form the
lateral boundaries of the mouth. The maxillse
are soft, membranaceous and adapted for
holding, rather than for comminuting the food
like the mandibles. They are in general also
furnished, as in the larva of Athalia, with two

other jointed organs, palpi or feelers which are
employed by the insect entirely as tactors.
Behind these parts is situated a second trans-
verse plate, the labium (/), or inferior lip,
which bounds the posterior part of the mouth.
This also, like the maxilla, is furnished with a
pair of jointed palpi. The motions of the man-
dibles and maxillae differ from those of the
jaws in vertebrated animals, being always from
side to side, and meeting, or passing across
each other like the blades of a pair of scissors.
Besides these parts, there is in many larvae a
projecting papilla situated within the mouth
upon the soft membrane of the labium. This
is conical and jointed, and is called by Messrs.
Kirby and Spence the spinneret. It is the
common excretory duct of the glands which
secrete the materials with which the insect spins
its coccoon, previously to undergoing its trans-
formations. In all larvae the antenna (g) are
but slightly developed. They are situated a
little above the base of the mandibles, on each
side of the clypeus. and are of a conical form,
jointed, and usually terminating in a point.
In some species they are three, but rarely
more than five-jointed. The eyes in all larvae
are single, or sessile, and not compound, or
aggregated together, as in perfect insects. In
the pseudo-caterpillars, Tenthredinida, as in
Athalia centifolia, there is only one large stem-
ma on each side of the head (A), situated above
the antennae ; but in the true caterpillars, Lepi-
doptera, as in the Sphinx ligustri, there are
always six very minute ones, placed at a little
distance from each other, in the form of an
arc near the base of the mandibles and antennae,
at the lateral part of the head. In the apodal
hymenopterous larvae which constantly reside in
the dark, the oral apparatus is developed, but
the eyes are in general entirely absent.

The form of the oral apparatus in the
maggots, or larvae of the Dipterous insects,
is entirely different from that of the insects we
have just described. In the larva of (Estrus
ovis instead of mandibles and maxillae crossing
each other transversely, the mouth is formed by
two fissures, the one anterior and longitudinal,
and the other posterior and transverse, the two
meeting each other in the form of the letter T
inverted thus j, (fig. 360). In the anterior
fissure (c) are situated two longitudinal power-
ful hooks, the mandibles (d} directed forwards
and downwards, and employed by the insect
both as organs of progression and nutrition.
At the base of these in the transverse fissure (e\
are two other hooks, maxillae, of a similar des-
cription, directed both to the median line, but
jointed like the mandibles in Myriapoda, and
crossing each other like the mandibles of the
true larva. The hooks thus include between
them the cavity of the mouth, in this manner
adapted both for wounding and tearing as well
as suction, and it is curious to observe that we
have here in the larva of a true insect an ap-
proach to the vermiform type of the permanent
condition of the oral apparatus of the leech. In
the maggot of the larder-flies and flesh-flies
above alluded to, the mouth is formed some-
what differently. Behind the transverse hooks

INSECTA.

873

the mouth is bounded by a membranaceous
labium, while at its anterior part it is furnished
with a proboscidal lip (fig. 358, B c), divided
into four very minute palpiform organs. There
are also two processes situated one on each
side of the mouth in the second segment. At
the base of the fourth segment are the two pro-
jecting orange-coloured organs of a semicircular
form, divided into what appear like single
pedunculated eyes, but which are in reality
external branchiae, and correspond to the spira-
cles of the pro-thorax of the perfect insect (A).
In the (Estrus ovis (fg. 360) the two sides of

length, and the parts of which they are
composed are readily distinguished. These

Head of larva of (Estrus ovis.

2, 3, 4, segment ; a, optic nerve ; b, epicranium ; c,
labium ; d, mandibles ; e, maxillce.

the fissure that forms the anterior part of the
mouth are developed into very distinct organs
of vision (A), in which may be traced the nerves
of two separate but nearly approximated eyes.
The existence of distinct eyes in this larva is
the more remarkable, from the circumstance that
the larva resides in the frontal sinus of the skull
of the sheep, where we sought for, and found
the identical specimens upon which our obser-
vations have been made.

Organs of locomotion. We stated above that
the true organs of locomotion are six in num-
ber, both in the larva and perfect state, and
that they are always attached to the second,
third, and fourth segments of the body. They
are distinguished from the false, or abdominal
legs by their possessing distinct articulations
or joints, by the strength and hardness of their
texture, and by their general pointed form. In
Coleopterous larvae they are of considerable

Fig. 362.

Fig. 361.

Fig. 361. Thoracic leg of larva of Cossus ligniperda
(Lyonet).

a, Coxa ; b, femur ; c, tibia ; d, tarsus ;/, ungui*.
Fig. 362. Abdominal leg.

are (Jigs. 361, 364 ***), as in the perfect
insect, the claw (/), the tarsus (d), the tibia
(c), the femur (6), and coxa, or hip (a). In all
terrestrial larvae the legs are attached to the
inferior parts of the segments; but in one
remarkable genus of water-beetles the great
Hydrous piceus, they were supposed by Frisch
to be attached so much nearer to the dorsal
than the sternal surface as to have the appear-
ance of being actually placed on the back. But
this is erroneous, the mistake having arisen
from the peculiar formation of the head, which
is flat on its upper, but convex on its under sur-
face. The whole of these thoracic legs, in all
larvae which possess them, are nearly equally
developed, and do not present any marked
difference of form or size, as is often sub-
sequently found in the perfect insects. In the
larvae of Lepidoptera they are exceedingly
short and pointed, and in many Hymenoptera
and Diptera are entirely absent. The false or
abdominal legs are totally different in appear-
ance and structure from the true or thoracic ones.
Although varying in number in different species,
they are universally present in the Lepidoptera
(Jig. 364, ftt) and in many Hymenoptera and
Diptera. In some instances, as in many of
the Geometrida, there is only a single pair at
the anal extremity of the body ; while in others,
as in some of the Tenthredinidte, there are as
many as eight pairs. In every instance they
are soft and membranaceous, without distinct
joints or articulations. In some of the Lepi-
doptera their structure is exceedingly curious,
and has been beautifully illustrated by Lyonet
(Jig. 362), in his anatomy of the larva of
Cossus ligniperda. In that insect their shape
resembles an inverted cone, with its apex trun-
cated to form a flat sole, or foot, upon which
the caterpillar walks. The sole in its middle
can be rendered concave at the will of the
animal, while around its margin are several
rows of minute hooks, directed outwards, and
when the sole of the foot is pressed firmly upon

874

INSECTA.

any surface in walking these hooks attach
themselves, and are released again when the
sole of the foot is contracted, previously to the
caterpillar's raising it to make another step
forwards. In the SphingidiE the abdominal
feet are formed of two parts, the external one,
broad, semicircular, and edged with minute
hooks, directed inwards like a claw, and the
internal one smaller, with its hooks directed
outwards, so that two parts of the foot are
opposed to each other, and grasp the surface
upon which they are walking like the foot of a
bird. It is with these that the Sphinx at-
taches itself so firmly to the stems and branches
of plants, that it is often almost impossible to
remove it without injury. In the Sphinx there
are four pairs of these legs, attached to the
seventh, eighth, ninth, and tenth segments,
besides one pair at the thirteenth, or anal ex-
tremity. In some Dipterous larvae the abdomi-
nal legs are the only organs of locomotion — as
in the rat-tailed larva of Eristalis tenax.

In every instance these abdominal legs are
only processes of the exterior covering of the
insect, furnished externally with peculiar deve-
lopments of the cuticle, in the form of hardened
spines or hooks like the claws and nails of ver-
tebrated animals, and internally with a greater
development of certain portions of the muscles
of the abdomen. We have full proof of this
in those numerous apodal larvae which are
capable of locomotion, as in most of the
Muscidte, the common maggots. In all these,
in which both the true and false legs are entirely
absent, the whole external surface of the body
is modified for this purpose. In the maggot
of the flesh-fly the whole anterior part of every
segment is surrounded and beset with numbers
of very minute hooks, with their apices directed
backwards. With these the larva attaches
itself to the surface over which it moves, and
carries itself along by the alternate contraction
and relaxation of the longitudinal muscles of
its body. A beautiful adaptation of these
dermal hooks to the peculiar habits of the
individual is observed on comparing their form
and position on the bodies of the larvae of two
very distinct species of (EstruSj the one (Estrus
ovis, parasitic in the head of the sheep, the
other beneath the skin on the backs of oxen,
(Estrus bovis. In the first of these larvae, which
moves about freely in its habitation, the hoojcs
(fig' 360) are all directed backwards around
the posterior margin of each segment, a direc-
tion rendered necessary for their employment
as organs of locomotion ; but in the latter insect,
which is confined to one spot for many months,
in the tumour occasioned by it on the back of
the ox in the cellular tissue beneath the skin,
the hooks are not required as organs of pro-
gression, but yet are rendered necessary for the
purpose of retaining the larva in its nidus un-
affected by the varied muscular movements of
the parts around it. To accomplish this object
each segment of the larva is provided with two
sets of hooks. One of these is arranged around
the anterior part of the segments, and consists
of very numerous minute sharp-pointed spines,
directed forwards, while the other is composed

of strong flattened scales with curved points,
very much larger but less numerous than the
preceding. These are disposed around the
posterior part of the segments, and have their
points directed backwards. The effect of the
spines thus placed in opposite directions evi-
dently is that of retaining the larva in exactly
the same position among the cellular tissue in
the back of the animal, while the greater
strength of the posterior spines enables it at
will to penetrate deeper beneath the skin of its
victim.

We have thus seen that in apodal larvae en-
dowed with powers of locomotion the place of
the true organs of progression is supplied by
peculiar developments of the cuticular covering
of the body, analogous to the scales on the
bodies of Ophidian Reptiles, and these are
employed by the larvae in all their progressive
movements in the same manner as the scales
on the body of the snake. But in those apodal
larvae which remain in the same locality until
they have passed through all their changes, as
the larvae of the bee and wasp, these develop-
ments of the cuticular surface do not exist, but
the body is perfectly smooth.

It is not always, however, that the spines
on the bodies of larvae are employed as organs
of locomotion since they exist on many larvae
which possess both true and false feet, and are
then either merely ornamental appendages or a
means of defence. But whatever be their use
in the economy of the larva, they are only
developments of its external covering, and
generally disappear when the insect undergoes
its change into the pupa state, being thrown off
with the skin.

Growth and changes of the larva. — The life
of an insect that undergoes a true metamor-
phosis is one continued series of changes from
the period of its leaving the egg to that of its
assuming the perfect state. These are not
merely from the larva to the pupa and from,
that to the perfect animal, during which the
insect gradually acquires new organs, but con-
sist also of repeated sheddings of its skin, which
occur at certain intervals before the larva has
attained its full size. These changes and the
circumstances connected with them have been
more particularly watched in Lepidopterous
insects, and have been carefully noted by many
naturalists, especially by those of the last cen-
tury, Redi, Malpighi, Gcedart, Merian, Ray,
Swammerdam, Reaumur, Lyonet, Bonnet, De
Geer, and others, who concur in their state-
ments respecting the manner in which these
changes are effected.

Almost immediately after the insect is
liberated from the egg it begins to feed with
avidity, and increases much in size. Accord-
ing to the observations of Count Dandalo* the
common silk-worm, Liparis mori, does not
then weigh more than one hundredth of a grain,
and is scarcely a line in length, but at the
expiration of about thirty days, when it has
done feeding and has acquired its full size, its

* Count Dandalo on Silk-worms (Eng. Trans.)
p. 326.

INSECTA.

875

average weight is about ninety-five grains, and
its length sometimes as much as forty lines.
During this period, therefore, it has increased
nine thousand and five hundred times its origi-
nal weight, and has eaten sixty thousand times
its weight of food. But observations on the
larva of the privet hawk moth, Sphinx lignstri,*
lead us to believe that this estimate of the
amount of food eaten is a little too great. The
larva of the sphinx at the moment of leaving
the egg weighs about one eightieth of a grain ;
at about the ninth day it casts its second skin
and then weighs about one-eighth of a grain :
on the twelfth day it changes its skin again
and then weighs rather more than nine-tenths
of a grain. On the sixteenth day it casts its
fourth skin and weighs three grains and a half,
and on the twenty-second day enters its sixth
and last skin and weighs very nearly twenty
grains; but on the thirty-second day, when it
has acquired its greatest size, it weighs nearly
one hundred and twenty-five grains, so that in
the course of thirty-two days this larva increases
about nine thousand nine hundred and seventy-
six times its original weight. At this period it
is sometimes more than four inches in length.
But this is not the greatest weight that the
larva attains. One specimen which was bred
in its natural haunts weighed one hundred and
forty-one grains and seven-tenths, so that in
this instance the insect had increased at the rate
of eleven thousand three hundred and twelve
times its original weight. But great as is this
proportion of increase, it is exceeded by some
other larvae. Lyonet found that the larva of
Cossus ligniperda, which remains about three
years in that state, increased to the amount of
seventy-two thousand times its first weight.f
This amazing increase is occasioned chiefly by a
prodigious accumulation of fat which exists in
a greater quantity in this than in most other
larvae. We have ourselves removed forty-two
grains of fat from one specimen, which was
more than one-fourth of the whole weight of
the insect. The occasion for this prodigious
accumulation is chiefly to supply the insect
during its continuance in the pupa state, while
the muscular structure of the limbs and other
parts of the body are in the course of develop-
ment ; and also to serve, perhaps, as an imme-
diate source of nutriment to the insect at the
period of its assuming the perfect state, and
more particularly during the rapid development
of its generative functions ; since, when these
have become perfected, the quantity that re-
mains is very inconsiderable. But all larvae do
not increase in these amazing proportions,
although their actual increase may be more
rapid." Those in which the proportion of in-
crease is the greatest are usually those which
remain longest in the pupa state, as in the
species first noticed. Thus Redil observed in
the maggots of the common flesh-flies a rate of
increase amounting to about two hundred times
the original weight in twenty-four hours, but
the proportion of increase in these larvae does

* Phil. Trans. 1837, part ii. p. 315.
t Traite Anat. de la Chenille, p. 11.
J De General. Insectorum, p. 27.

not at all approach that of the sphinx and
cossus. From observations made on the larva
of one of the wild bees, Anthophora retusa, we
believe that this is also the case with the Hy-
menoptera. The weight of the egg of this
insect is about the one hundred and fiftieth
part of a grain, and the average weight of a
full-grown larva six grains and eight tenths, so
that its increase is about one thousand and
twenty times its original weight ; which, com-
pared with that of the sphinx of medium size,
is but as one to nine and three-quarters, and to
a sphinx of maximum size only as one to a
little more than eleven.

The changes of skin which a larva undergoes
before it enters the pupa state are more or less
frequent in different species. In the generality
of Lepidopterous insects it occurs about five
times, but in one of the tiger-moths, Arctia
Caja, according to Messrs. Kirby and Spence,*
ten times. A few hours before the change is
to take place the larva ceases to eat and remains
motionless, attached by its abdominal legs to
the under-surface of the twig or leaf upon
which it has been feeding. Many species spin
a slight web or carpet of silk in which they
attach their posterior legs, as observed by Dr.
Pallas of Apatura iris,-\ and in this manner
await their change, which appears to be attended
with much uneasiness to the insect. The whole
body is wrinkled and contracted in length. In
the sphinx this contraction occurs to so great
an extent in some of the longitudinal muscles
of the anterior and middle part of the body
that the larva assumes that peculiar attitude
from whence the genus derives its name. In
this attitude the larva remains for several hours,
during which there are occasionally some
powerful contractions and twitchings of its
whole body, the skin becomes dry and shri-
velled, and is gradually separated from a new
but as yet very delicate one which has been
formed beneath it, and the three or four anterior
segments are greatly enlarged on their dorsal
but contracted on their under surface. After
several powerful efforts of the larva the old
skin cracks along the middle of the dorsal
surface of the second segment, and by repeated
efforts the fissure is extended into the first and
third segments, and the covering of the head
divides along the vertex and on each side of
the clypeus. The larva then gradually presses
itself through the opening, withdrawing first its
head and thoracic legs, and subsequently the
remainder of its body, slipping off the skin
from behind like the finger of a glove. This
process, after the skin has once been ruptured,
seldom lasts more than a few minutes. When
first changed the larva is exceedingly delicate,
and its head, which does not increase in size
until it again changes its skin, is very large in
proportion to the rest of its body. In a few
hours the insect begins again to feed most
voraciously, particularly after it has entered its
last skin, when its growth is most rapid. Thus
a larva of Sphinx ligustri, which at its last

* Vol. i.

t Trans. Ent. Society, vol. ii. part ii. p. 138.

876

INSECTA.

change weighed only about nineteen or twenty
grains, at the expiration of eight days when it
was full-grown weighed nearly one hundred
and twenty grains. Most larvae immediately
after changing their skins remove to fresh
plants, but some, as the larvae of a beautiful
moth, Episema caruleocephala, devour their old
skins almost immediately they are cast, and
sometimes one another when deprived of food.
But it is not merely the external covering
which is thrown off during these changes ; the
•whole internal lining of the alimentary canal
also comes away with the skin, as was formerly
noticed by Swammerdam,* and repeatedly ob-
served by ourselves and others. The lining of
the mouth and pharynx with that of the man-
dibles, is detached with the covering of the
head, and that of the large intestines with the
skin of tlie posterior part of the body, and
besides these also, the lining of the tracheal
tubes. The lining of the stomach itself, or that
portion of the alimentary canal which extends
from the termination of the esophagus to the
insertion of the so called biliary vessels, is also
detached, and becomes completely disintegrated,
and appears to constitute part of the meconium
voided by the insect on assuming its Imago
state. Herold, however, has denied that this
change ever occurs in the alimentary canal, and
says that in the trachea it takes place only in the
larger stems. But Swammerdam states that he
saw it in the larva of the rhinoceros beetle,
Oryctes nasicornis, which shed both the lining
of the colon, and of the delicate as well as larger
branches of the tracheae,f and BonnetJ had wit-
nessed a similar occurrence. Burmeister§ has
also seen it, both with respect to the colon and
tracheae, in some of the Libellulse, and we now
add our own testimony to the fact of its occurring,
not simply at the extremities of the canal, but
throughout its whole extent, as we have dis-
tinctly seen during the changes of the nettle-but-
terfly, Vnnessa urtica.\\ It is more distinctly
observed when the larva is changing into the
pupa state than at any other period, although
we believe that it really does take place at
every change of skin. Hence these changes
are of the greatest importance to the larvae,
which often perish during their occurrence.
They are undergone by all larvae which possess
the true organs of locomotion, but it has been
questioned whether they are common also to
the apodal larvae, more particularly those which
constantly remain in the same locality until
they have changed into pupae or nymphs.
Reaumur and Hubert state that the larva of
the common hive-bee does not change its skin,
but only grows larger ; Swammerdam,** on the
contrary, asserts that it does, and also that he

* BibliaNat.

t Biblia Nat. p. 129, 134, 239, &c.

Contemplation de la Nature, torn. ii. p. 48.

$ Manual of Entomology, (Trans.) 1836, p. 428.

|| Since these remarks were written, a paper by
Mr. Ash ton upon this subject has been read at a
late meeting of the Entomological Society, Nov. 5,
1838, in which the statements of Swammerdam
respecting these changes have been fully confirmed.

f Kirby and Spence, Introduc, vol. hi.

** Biblia Nat. p. 163, a.

has observed the same thing in the alimentary
canal of the hornet.* Burmeisterf believes that
it does not take place, and states positively
that the larvae of Diptera do not moult. We
have watched for these changes in the larvae of
the wild bee, Anthophora retusa, but have been
unable to observe them, although we believe
they do really occur. But the universally ac-
knowledged accuracy of most of Swammer-
dam's observations, supported as they are in this
instance by analogy, fully warrants us in con-
sidering this subject as still open for enquiry.

When a full-grown larva is preparing to
change into the pupa state it becomes exceed-
ingly restless, ceases to eat, and diminishes
much in weight. Many species spin for them-
selves a covering of silk, termed a coccoon,
or case, in which they await their transforma-
tion. Others prepare little cavities in the earth
and line them with silk for the same purpose,
(Jig. 363), and others suspend themselves by

Fig. 363.

Section of the coccoon or winter nidus of Atha.Ua
centifolifB, natural size and magnified. Newport,
Prize Essay.

their anal prolegs to the under surface of a leaf.
In each of these instances this important change
takes place in the same manner. Before the
larva thus prepares itself for metamorphosis its
alimentary canal is completely evacuated of its
contents, its body, as at the previous changes of
skin, becomes dry and shrivelled, and much
contracted in length, and certain enlargements
at the sides of the anterior segments indicate
the now rapidly developing parts of the future
pupa. These changes take place in all insects
in a similar manner, but have been most fre-
quently watched in Lepidoptera, upon which
also our own observations have been made.
We have also observed the same changes in
Hymenoptera. The larva of the sphinx, when
it is ready to undergo its changes, penetrates
the earth to the depth of a few inches, and
there forms for itself a little chamber, in which
it awaits its transformation. But the butterfly
either fastens itself by a little rope of silk,
carried across its thorax, to the under surface
of some object, as a ceiling, &c., or suspends
itself vertically by its prolegs, with its head
directed downwards, as is the case with the
common nettle butterfly, Vanessa urtica. We
have watched these changes with much care in

* Ibid. p. 133, a.
t Transl. p. 432.

INSECTA.

877

this insect, -which frequently remains thus
suspended more than ten or twenty hours be-
fore the transformation takes place. During
this time the four anterior segments of the
larva become greatly enlarged, and the seg-
ments assume a curved direction, occasioned
by the contraction, or shortening of the muscles
of the under surface of those segments, which
are repeatedly slowly extended and shortened,
as if the insect were in the act of laborious
respiration. This generally takes place at short
intervals during the two hours immediately pre-
ceding the change, and increases in frequency
as that period approaches. When the period
has arrived, the skin bursts along the dorsal
part of the third segment, or meso- thorax, and
is extended along the second and fourth, while
the coverings of the head separate into three
pieces. The insect then exerts itself to the
utmost to extend the fissure along the segments
of the abdomen, and in the meantime pressing
its body through the opening gradually with-
draws its antennae and legs, while the skin, by
successive contortions of the abdomen, is slip-
ped backwards and forced towards the extre-
mity of the body, just as a person would slip
off his glove or his stocking. The efforts of the
insect to get entirely rid of it are then very
great; it twirls itself in every direction in order
to burst the skin, and when it has exerted
itself in this manner for some time, twirls
itself swiftly, first in one direction, then in the
opposite, until at last the skin is broken through
and falls to the ground, or is forced to some
distance from it. The new pupa then hangs
for a few seconds at rest, but its change is not
yet completed. The legs and antennae, which
when withdrawn from the old skin were dis-
posed along the under surface of the body, are
yet separate, and do not adhere together as
they do a short time afterwards. The wings are
also separate and very small. In a few seconds
the pupa makes several slow but powerful
respiratory efforts ; during which the abdominal
segments become more contracted along their
under surface, and the wings are much en-
larged and extended along the lateral inferior
surface of the body, while a very transparent
fluid which facilitated the slipping off of the
skin, is now diffused among the limbs, and
when the pupa becomes quiet dries, and unites
the whole into one compact covering.* Ex-
actly the same thing occurs in the changes of
the sphinx. The limbs at first are all separate,
each one inclosed in its distinct sheath, but
within a very short period after the change they
become agglutinated together by the fluid
effused between them, and form the solid ex-
terior of the pupa case. The body of the insect
is now divided into three distinct regions, head,
thorax, and abdomen. The first step towards
this division is the contraction which takes place
in all the longitudinal and diagonal muscles of
the body, soon after the larva (Jig. 364) has ac-
quired its full size, by means of which each seg-
ment of the insect forms a slight intussusception,
the anterior margin of one segment being drawn

* See also Entomologist's Text-book, p. 208.

Fig. 364.

Section of larva of Sphinx ligustri j 1 to 13, (dorsal
surf ace ) segments ', 1 to 12, (ventral surf ace ) ganglia ;
a, dorsal vessel ; b, its lateral muscle ; c d, oesophagus
and stomach ; e, ilium ; f, hepatic vessels ; g, caecum
coli ; h, colon and rectum j i, testis • * * thoracic
legs ; t f t abdominal legs. Newport, Phil. Trans.

under the posterior margin of the one which im-
mediately precedes it. This occurs in all the
segments which form the abdominal region of
the future moth, the nine posterior ones of the
larva. When the period of changing into the
pupa state has arrived, a much greater shortening
takes place in the muscles of the fifth and sixth
segments, and in some insects this is carried to so
great an extent that the whole body becomes con-
stricted in the fifth segment like an hour-glass,
and is thus divided into two distinct regions,
thorax and abdomen. The same change takes
place also in the muscles of the first and second
segment, by means of which the region of the
head is divided from that of the thorax (Jig. 365).
These duplicatures of the external covering are
carried to a greater extent on the under surface
of the first four segments than on the upper,

878

INSECTA.

Fig. 366.

Section of pupa of sphinx ligustri ; 1 to 13, dorsal
surface, number of segments ; 1 to 12, ventral sur-
face, number and position of ganglia ; a, dorsal ves-
sel; b, its lateral muscles; c d, oesophagus and sto-
mach ; e, ilium ; f, hepatic vessels ; g, colon ; h,
rectum; i, double testis; k, brain. Newport, Phil.
Trans.

and form the divisions between the legs of the
perfect insect, — the bony processes of the
sternal surface to which some of the principal
muscles are attached. On the upper surface
of the same segments they in like manner be-
come the phragmata, or bony partitions of the
dorsal surface. The fifth segment becomes al-
most entirely atrophied, and the sixth very
much shortened. A part of the fifth segment
forms a portion of the posterior surface of the
thorax of the perfect insect, (Jig. 366) while the
remainder constitutes the petiole or neck which
connects the abdomen with the thorax, the
sixth being the first true segment of the ab-
dominal region. Exactly the same changes
take place in Hymenopterous insects, and in
every other species in which we have had
opportunities of watching them. We have
before alluded to the opinion of Dr. Ratzeburg
that the head in Hymenopterous insects is com-
posed of two segments of the larva, because
just before the change into the nymph or pupa
state a portion of the head is found beneath the
integuments of the second segment. The fact
is indisputable, but the explanation of it appears
to be this. The true head of the Hymenopterous
larva consists of but one segment, which is
provided with the organs of manducation and
sensation the same as in the Lepidopterous.
But the head in this larva ceases to become
larger after a certain period, while the other
segments of the body continue to grow, and
ultimately acquire a diameter more than double
that of the head. Now the parts which are
to form the head of the future nymph continue

Section of perfect state, Sphinx ligustri ; letters and
figures as in section of pupa. Newport, Phil. Trans.

also to grow beneath the unyielding cranium,
from which, as the change approaches, they
become detached, and are gradually developed
backwards, and encroach upon the anterior
portion of the second segment. This, in ac-
cordance with the laws of development, as
established by Geoffrey St. Hilaire, that in
proportion as one part of an organized body is
increased beyond its ordinary size, the part
or parts in its immediate vicinity are in a cor-
responding degree arrested in their develop-
ment, becomes so much reduced, that in the
nymph, this second segment, which in the
larva is of the same size as the third and suc-
ceeding ones, has not half its original extent,
and being still further reduced in that state con-
stitutes at length the atrophied, and almost ob-
literated pro-thorax of the perfect insect. But
while the second segment is thus encroached
upon by the first it is in like manner encroached
upon from behind by the third, the immense
meso-thorax, which supports the chief organs
of flight in the perfect insect. The fourth
segment from the same cause is developed
backwards, and the fifth, diminished to a very
small size, exists only as in the sphinx as the
petiole which connects the thorax with the
abdomen, thus leaving the nine posterior seg-
ments of the larva to the latter region, as stated
when alluding more particularly to the number
of segments in hymenopterous larvae. The
necessity for this additional segment in the
abdomen of these larvae is a matter of much
interest, and appears to be connected with the
development of an apparently additional organ

INSECTA.

879

in the females of this class, a circumstance
to which we shall return in our description
of the skeleton of the perfect insect.

The Pupa. — We have seen that after leaving
the larva or feeding condition, the insect as-
sumes one of a very different form, which is
called the pupa, nymph, aurelia, or chrysalis
state. The two latter terms were applied by
the older entomologists to this stage of transfor-
mation in butterflies and moths. The term aure-
lia was used, as expressive of the beautiful gol-
den colours or spots with which many species are
adorned, as Vanessa urticte, v. atalanta, and
others. The term chrysalis had a similar sig-
nification. Linnaeus, desirous of employing a
term that would be applicable to this stage of
transformation in all insects, adopted that of
pupa, because in a large majority of the class
the insect is as it were swathed (Jig. 367) 'or

Fig. 367.

Pupa of DeHephila Elpenor. ElepJiant hawk^moth.

bound up, as was formerly the practice of
swathing children. This kind of pupa, in
which the future limbs are seen on the out-
side of the case, is called obtected. The term
nymph, which is sometimes employed, is
applicable only to those species in which the
limbs remain free, but are folded up, as in
the pupae of the butterfly and moth, and are
not covered with a hard uniform case; as in
many Coleopterous and most Hymenopterous
insects (Jig. 368). When the pupa is in-

Fig. 368.

Nymph or pupa state of Vespa crabo.
Magnified.

Hornet.

closed in a smooth uniform case, but no signs
of the limbs or other parts of the body are
visible, as in Diptera, it is called coarctate.
In these insects the skin of the larva is not
cast off at the period of changing, but becomes
the covering or coccoon of the included pupa,
which is also inclosed in its own proper skin
within it. In all insects which undergo a com-
plete metamorphosis, this is the period of quies-
cence and entire abstinence. Many species
remain in this state during the greatest part
of their existence, particularly the true pupae
of moths and sphinges, which often continue
in it for nearly nine months of the whole
year. But in 'most of those insects which as-
sume the particular condition of nymph, in
which the body remains soft and delicate, as
the hornets, ants, and bees, the pupa state is
the shortest period of existence, being often
scarcely more than a week or ten days. In
every species the length of this period is much
affected by the influence of external circum-
stances. Thus if the larva of the common net-
tle-butterfly, Vanessa urtictE, change to a chry-
salis in the hottest part of the summer, it will
often, as we have found, be developed into the
perfect insect in eight or nine days ;* whilst if
its change into the chrysalis takes place at
the beginning of summer, it is fourteen days
before the perfect insect appears ; and if it en-
ters the chrysalis state at the end of summer, it
remains in that condition through the winter
until the following spring. On the other hand,
as was proved by Reaumur, if the chrysalis be
placed in an ice-house, its development into
the perfect insect may be retarded for two or
three years. Again, if the chrysalis be taken in
the midst of winter into a hot-house, it is deve-
loped into the perfect insect in from ten to
fourteen days. This period of quiescence is
absolutely necessary in all those species which
undergo an entire change of form and habits,
for the completion of those structural metamor-
phoses by which the creature is not only adapted
to the performance of new functions, but is
equally incapacitated for the continuance of
some of those which it has previously enjoyed.
During this period it is that new parts are deve-
loped, and the insect's mode of life is in conse-
quence entirely changed. Whilst these altera-
tions are taking place in the organic structures,
the functions of the organs themselves are in a
great measure suspended, and the condition of
the insect becomes that of the hybernating ani-
mal. Respiration and circulation are reduced
to their minimum,f and the cutaneous expendi-
ture of the body is then almost unappreciable
even by the most delicate tests. J Thus a pupa
of Sphinx ligustri, which in the month of Au-
gust, immediately after its transformation,
weighed 71.1 grains, in the month of April fol-
lowing weighed 67.4 grains, having thus lost
only 3.7 grains in the long period of nearly
eight months of entire abstinence. The whole
of this expenditure, therefore, had passed off

* Phil. Trans. 1834, part 2, p. 416.
t Phil. Trans. 1836, part 2, pp. 555-6.
$ Idem. 1837, part 2, p. 323.

880

INSECTA.

by the cutaneous and respiratory surfaces. But
when the changes in the internal structures are
nearly completed, and the perfect insect is soon
to be developed, the respiration of the pupa is
greatly increased, and the gaseous expenditure
of its body is augmented in the ratio of the
volume of its respiration, which is greatest the
nearer the period of development. Thus in the
same insect in which the diminution of weight
was so trifling during eight months' quiescence
and abstinence, it amounted in the succeeding
fifty-one days to nearly half the original weight
of the pupa, since the perfect insect, imme-
diately after its appearance on the 24th of May,
weighed only thirty-six grains.

This increased activity of function is attended
with a correspondent alteration in the general
appearance of the pupa. In the sphinx all the
parts of the future Imago become more and
more apparent on the exterior of the pupa case,
the divisions into head, thorax, and abdomen
are more distinctly marked, the eyes, the an-
tennae, and the limbs appear as if swollen and
ready to burst their envelope, and the pupa
gives signs of increasing activity by frequent
and vigorous contortions of its abdominal seg-
ments. The naked pupa or nymph, in which,
as we have seen, all the parts of the body are
free, and encased only in a very delicate mem-
brane, acquires a darker colouring and a firmer
texture, while the species which undergo their
metamorphoses into nymphs in the water, Tri-
choptera, the caddis-flies, acquire a power of lo-
comotion as the period of their full develop-
ment approaches, to enable them to creep up
the stems of plants, and leave that medium in
which it is impossible for them to exist as per-
fect insects.

In every instance the assumption of the per-
fect state is accompanied by a slipping off of
the external covering. Before this can be ef-
fected, many Lepidoptera, like the Trichoptera,
have first to remove themselves from the locality
in which they have undergone their previous
metamorphoses. When this happens to be in
the interior of the trunks of trees, or in other
situations from which it is difficult to escape,
the abdominal segments of the pupa are often
beset with minute hooks (fig. 367), similar to
those on the feet of the larva. By means of
these, by alternately contracting and extending
its abdominal segments, the pupa is enabled to
force an opening through its silken coccoon, or
to move itself along until it has overcome the
obstacles which might oppose its escape as a
perfect insect.

The imago or perfect state. — Immediately
after the insect has burst from the pupa case it
suspends itself in a vertical position with its
new organs, the wings, somewhat depending,
and makes several powerful respiratory efforts.
At each respiration the wings become more and
more enlarged by the expansion and extension
of the tracheal vessels within them, accompa-
nied by the circulatory fluids. When these
organs have acquired their full development
the insect remains at rest for a few hours and
gains strength, and the exterior of the body be-
comes hardened and consolidated, and forms,

what we shall presently consider, the Dermo-
skeleton. This is what takes place in Lepidop-
terous insects. Some of the Coleoptera, as in
the instance of Melolonthu vulgaris, the com-
mon chaffer-beetle, remain for a greater length
of time in their nidi before they come abroad
after entering the imago state. This is also the
case with the Humble-bees. When these in-
sects first come from their cells they are exceed-
ingly feeble, their bodies are soft, and covered
with moisture, their thick coating of hairs has
not acquired its proper colour, but is of a gray-
ish white, and they are exceedingly susceptible
of diminished warmth. They crowd every
where among the cells, and among other bees,
where there is most warmth. In a few hours
this great susceptibility is diminished, and their
bodies acquire their proper colours, but they
do not become sufficiently strong to be capable
of great muscular exertion, and undertake the
labours of the nest until the following day.

When an insect has once entered its perfect
state, it is believed to undergo no further meta-
morphosis or change of covering. But there
exists an apparent exception to this general law
in the Ephemeridtf, which are noted for the
shortness of their existence in the imago state.
When these insects have crept out of the water,
and rid themselves of the pupa covering, and
their wings have become expanded, they soon
take flight, but their first movements in the air
are performed with some difficulty, and they
shortly alight again and throw off a very deli-
cate membrane with which every part of the
body has been covered, and then resume their
flight with increased activity. The condition
of the insect previously to this final change has
been called by Mr. Curtis the pseudimago state.
It was noticed long ago by Swammerdam, and
has usually been thought to be peculiar to the
Ephemerida, but occurs also in the Lepidoptera
and Diptera* but in them takes place at the
same time with the change from the pupa state.
Swammerdam thought the change peculiar to
the males of the Ephemerid<z, but Mr. West-
wood has seen it also in the females.

Many insects, of which the Ephemerida and
BombycidsE are known examples, take no food
in the perfect state, and exist only for a few
hours, or at most only a few days, the business
of life being almost entirely devoted to the pro-
pagation of the species. In every instance of
the entire abstinence of a species in the perfect
state there is a corresponding atrophy of the
parts of the mouth. This we shall find is. the
case in the Ephemera, in the gad-fly, (Estrus,
and in the silk-worm moth. In the latter in-
stance the parts of the mouth are simply so
much diminished in size as to be unfitted for
taking food; in the former they have almost
disappeared. On the other hand, when the life
of the imago is continued for a long period, all
the parts of the mouth are fully developed.
The duration of life in these species often ex-
tends for many weeks, or in some even months,
and the quantity of food taken is consequently
greater than is taken by the larva. In those

* Westwood's Introduction, &c. vol. ii. p. 28.

INSECTA.

881

instances in which the life of the imago is ex-
tended beyond the usual period, it appears to
result from one of the great objects of existence
being unaccomplished; the insect is always in
a state of celibacy, in which condition the life
of an ephemera may be extended to several
days, and perhaps even to two or three weeks.*
1. Der mo-skeleton. — The skeleton of insects
is formed of a modification of the external
coverings of the body, together with certain
ossified portions situated within the head and
thorax, to which some of the most important
muscles are attached. Hence it is called a
dermo-skeleton. The true organs of support are
thus placed on the exterior instead of the inte-
rior of the body, and the solid skeleton, impact-
ing the whole, as it were, in a coat of mail, gives
additional strength to the delicate limbs by
affording a larger surface for the attachment of
muscles, while it more securely protects the
bodies of these diminutive, but exquisitely
formed little creatures, from the injuries to
which they are constantly exposed. Tims, then,
in the strength and position of the skeleton, in-
sects have as striking affinities with the Chelo-
nian Reptiles as they have, as we shall hereafter
see, with Birds in the extent, distribution, and
activity of their respiratory organs; and with
the hibernating Mammalia in their maintaining
an elevated temperature of body only when in a
state of activity. Some naturalists, however,
have contended that the analogies which were
traced, first by our illustrious countryman
Willis in the year 1692, and subsequently
by Geoffroy St. Ililaire and other comparative
anatomists, between the dermo-skeleton of in-
sects and the proper skeleton of vertebrated ani-
mals, are incorrect, and that the structure ought
rather to be regarded as the analogue of the
skin than as that of the osseous system, and
hence they have compared it only with the
nails, horns, and other appendages of the epi-
dermis. These objections receive additional
weight and importance from the circumstance
that one set of organs, the elytra, which form
part of the hardened coverings, are actually de-
rived from the respiratory structures. But it may
be remarked in reply, that the skeleton of in-
sects, both in its office and ultimate composition,
resembles more the bones of Chelonian Reptiles,
which, like it, are covered with a thin cuticular
lamella, and placed on the exterior of the body,
than the true skin or the epidermis. Hence we
shall continue to regard and describe it as sub-
servient to the same purposes in these diminu-
tive creatures as the osseous system in vertebrata.
This view of its real nature is justified, as we
shall presently see, by analyses of its chemical
constituents. The peculiar characteristic of
bony structure is the presence of a large propor-
tion of a particular kind of earthy matter, and
this is also one of the great characteristics of the
coverings of insects, which become consolidated
during the changes, by the deposition of a quan-
tity of the same kind of earthy matter within
them. But we cannot regard the coverings thus
formed as merely exsiccated non-vascular struc-

* Op. cit. p. 27.

VOL. ir.

tures ; on the contrary, we beliere them to be
nourished by the circulatory fluids, perhaps to
as great an extent as the external skeleton of
Chelonia. In support of this opinion it may be
remarked that those internal processes which
exist in the perfect state, and are developed
during the metamorphoses from duplicatures of
the external tegument, perform most important
offices in the body as organs of support and
attachment for powerful muscles. It can hardly
be imagined that these internal processes are
not nourished by the circulatory fluids like the
muscles that are attached to them, while it is well
known that every part of the external covering is
penetrated by ramifications of the air-vessels, the
course of which in the wings has recently been
shown to be always indicative of the passages
along which the blood circulates.* Hence it
is fair to infer that every part of the animal sup-
plied with tracheae is also nourished by the cir-
culatory fluid, as well in the exterior skeleton of
the thorax and abdomen as in the hardened elytra
and wings, in which the presence of the fluid
has been actually detected by its movements.

Chemical composition. — The peculiar sub-
stance that constitutes the hard portion of the
dermo-skeleton is called chitine by Odier, and
entomoline by Lassaigne. The most generally
received name is chitine. M. Odier, who first
analysed the coverings of insects, and disco-
vered this substance,f found that it constitutes
about one-fourth part of their whole weight,
and that the remaining three parts consist of
albumen, extractive matter soluble in water, a
coloured oil soluble in alcohol, and a brown
animal substance soluble in potass, but insolu-
ble in alcohol. The latter substance, which
exists in considerable quantity, was found by
Lassaigne to be analogous to the peculiar ani-
mal matter of cochineal, coccine, and that it
forms the basis of the colouring matter of the
skeleton. The composition of chitine has been
differently stated by chemists, but by all it has
been shown to be perfectly distinct from horn,
the nails, and other appendages of the epidermis,
in being quite insoluble in a hot solution of
caustic potass, and in not fusing or swelling up
like horn when burnt at a red heat, but leaving
a white ash, which retains the original form of
the part. This sufficiently proves that the co-
verings of insects cannot properly be compared
with the mere epidermis or its appendages.
According to Odier, chitine is obtained by di-
gesting the hard parts of the skeleton in a hot
solution of caustic potass, renewed several
times, until it has ceased to have any action
upon them. The solution, by removing the
colouring matter and other constituents, be-
comes of a deep brown, and leaves the chitine
nearly as transparent as horn, without any
change of form. This substance, as we have
before stated, constitutes about one-third or
fourth of the weight of the whole skeleton, and
was believed by Odier to contain no nitrogen,

* Bowerbank, Observations on the circulation of
blood and the distribution of the trachea? in the wing
of Chrysopa perla, Ent. Mag. No. 17, Oct. 1836.

t Memoires de la Societe d'Hist. Natur. de Paris,
torn. i. Zoological Journal, vol. i. p. 101, Mar.1824.

3 M

882

INSECTA.

on which account it was compared by him to
lignin, the basis of woody fibre. He believed
also that it contains no carbonate of lime, the
earthy salts being chiefly phosphate of lime,
with carbonate of potass and a little phosphate
of iron. Mr. Children, however, by a more
careful and different mode of analysis, proved
that chitine is composed of carbon, hydrogen,
nitrogen, and oxygen, in about the following
proportions, the mean which we have deduced
from his details of two careful analyses :

Grs.

Carbon 46.08

Hydrogen 5.96

Nitrogen 10.29

Oxygen 37.4 1

99.74

and that, in addition to the earthy salts men-
tioned by Odier, there are also small propor-
tions of silica and magnesia, and a slight trace
of manganese ; and it has since been stated
that there is likewise a trace of carbonate of
lime.* Some authors still imagine that chitine
contains no nitrogen ;f but in the careful expe-
riments of Mr. Children, who was assisted by
Professor Daniell,J the formation of prussic
acid, which took place during the analysis, was
decisive of the fact of its existence.

Thus, then, in the distinctness of its chemical
composition from that of horn and other dermal
appendages, and in its similarity to that of true
bone, in the greater proportion of its earthy
matter being phosphate of lime, may we not
venture to infer that chitine, the basis of the
insect skeleton, is intermediate in its chemical
condition between the ossitic and dermal struc-
tures ; or, in other words, is an imperfectly de-
veloped condition of bony matter, so modified
that, while it is subservient to the great purpose
of animal life, in affording strength and solidity
to the parts in which it exists, it at the same
time admits of their performing all the organic
functions of the true skin ?

If such be not the case, it will be difficult
satisfactorily to account for the solidification of
those internal processes which, in insects, occupy
the position and perform the office of the true
bones in vertebrata, but which are originally deri-
ved from the external teguments. Thus we shall
find that in the cranium of some of the Coleop-
tera, the most perfect insects, the cerebral gan-
glia are protected on either side by more or less
perfectly developed laminae of this bone-like
structure; that the first suboesophageal ganglion
actually lies in a cradle of the same, and that
the nervous cord itself, before passing out of
the cranium, is not only protected laterally by
continuations of these lamina?, but is often in-
closed in a distinct bony ring. But it may be
said that the exuviation of the coverings of in-
sects during the early period of life, when un-

* Professor Owen's Lectures at the Royal Col-
lege of Surgeons, May 1837.

t Professor Grant, Lancet, Dec. 7, 1833, p. 393.
Bunueistrr, Manual of Entomology, (translation,)
1836, p. 230.

$ ZoolofcicalJournal, March 1824, p. 115.

dergoing their metamorphoses, and a like con-
dition in other articulata, is opposed to this
opinion. To this we reply, that in all true in-
sects exuviation of the skeleton takes place
only during the growth and metamorphoses of
the individual, and that when these are com-
pleted, and the insect has arrived at its adult
condition, when its body no longer continues to
be enlarged, the then perfect skeleton is per-
sistent throughout the remainder of life, which,
as in the hive-bee, may continue for many
months, and under some circumstances, as has
been known among the Coleoptera, even for
two or three years. The exuviation of the ske-
leton of Crustacea, which are said to continue
to grow throughout the whole period of their
existence, is similar to that of insects, and per-
haps in both is induced, not alone, as usually
supposed, by the mere mcasement of the animal
in a covering which prevents the further growth
of its body, but by changes in the actual con-
dition of the skeleton itself, dependent upon
the same laws of existence which regulate the
removal of the old and the deposition of new
matter in the bones and other structures of the
vertebrata.

Of the manner in which chitine is deposited
in insects we have no direct information.
Latreille considers it to be a solidification in the
mucous tissue, and Dr. Grant affirms it to be
a deposition upon the true skin. This appears
also to have been the opinion of Odier, who
found chitine in theexuviable skeleton of Crus-
tacea, in which he says it exists in the form of
lamellae.* In whatever form it is deposited, it
is intimately connected with the true corium,
into the composition of which it appears to
enter. It is covered by the colouring matter,
and also with a distinct epidermis like the
horny cuticle on the carapace of Chelonia. On
comparing the experiments of M. Odier and
Mr. Children the quantity of chitine appears to
vary a little in different insects.f A curious
circumstance mentioned also by Odier is that
it appears to enter into the composition of the
trachea? of the wings, but not into that of their
connecting membranes. If this be the case, it
is a further proof that the skeleton ought no! to
be compared to the epidermal appendages of
vertebrata.

The skeleton consists of thirteen distinct seg-
ments, which are believed to be its normal
number in all insects. But recent observations
on the larva? of Hymenoptera and Diptera,
before alluded to, render it probable that this is
not the full amount, and that the number is at
least fourteen, at all events in some species.
Mr. Westwood has already shown this to be
the case in Hymenoptera, and that in the per-
fect state of Forficulal there are thirteen dis-
tinct segments in the male, and, also in a
rudimentary state, in the female, besides the
anal forceps. We have ourselves invariably
found fourteen in the apodal larvae of Hymen-
optera and in some of the Diptera; but we

* Zoological Journal, vol. i. March, 1824, p. 108.

+ Op. cit.

t Trans. £nt. Society, vol. i. p. 157, et seq.

INSECTA.

883

were not prepared to meet with anything like
an approach to the same number in a perfect
insect. In the female of the Gryllotalpa
vutgaris we have found nine distinct segments
in the abdomen, besides the post-scutellum,
which resembles a tenth one in a rudimen-
tary condition on the dorsal surface between
the meta-thorax and base of the abdomen. In
the male of the same species there are also nine
distinct segments, but the penultimate and
ante-penultimate are in a rudimentary con-
dition, corresponding to those in the female
Forficula. The post-scutellum at the base of
the meta-thorax is as much developed as in
the female, and is very distinct as a portion
of the meta-thorax. \Ve have also found
the same number in a foreign species, Gryl-
lotalpu didact>/la. The similarity in the num-
ber of segments thus appears to connect the
Gryllutulpte with the Forjiculte. These va-
riations in perfect insects lead us to hesitate
in admitting thirteen to be the normal number
of segments, especially as we shall presently
endeavour to show that the head itself is com-
posed of more than one. The varied forms of
the body in the different classes are entirely
dependent upon the extent to which these
primary segments are developed, whatever be
their true number, and chiefly upon the greater
or less development of parts of the first four seg-
ments. But whether the changes in these seg-
ments be greater or less, they are always in
reference to the habits or economy of the indi-
dividual. Thus in the Coleoptera and Orthop-
tera the parts of the mouth are nearly equally
developed, and are admirably fitted for all the
purposes of manducation. In the Lepidoptera
some of these parts are developed to their
greatest possible extent, the consequence of
which is that the neighbouring parts become atro-
phied, and leave scarcely a trace of their former
existence. This is the case with the mandibles
and lips, the most conspicuous parts of the
mouth in the larvae of this order. In the imago
the maxillae are greatly elongated, and altered in
shape, to form a flexible tube, because the per-
fect insects are destined to take their food in a
liquid state, and because still further, the food
is produced in situations where it would be in-
accessible to the insect, were the mouth of the
same form as in those the food of which re-
quires to be comminuted by the jaws, before it
is passed into the stomach.* Then again in the
same segment in which the oral organs are
nearly equally developed, other parts are often
enlarged, and in like manner encroach upon
those which are in immediate connexion with
them. In the rapacious Neuroptera which
obtain their food solely by means of the organs
of vision, and are constantly hawking in search
of it in the brightest light, the corneae of the
eyes are expanded over nearly two-thirds of the
whole surface of the head, and in consequence
reduce to their minimum of development those
parts which are most conspicuous in the head
of Coleoptera, which usually obtain their food

* See Newman on the External Anatomy of
lu sects, p. 13.

by the aid of other senses. The causes which
regulate the development of the segments of the
thorax are exactly those which influence the
development of the head. In the mole-cricket,
which burrows in the earth for its food, the
second segment, or pro-thorax, with its ap-
pendages the anterior extremities, is enlarged
to its greatest extent, because it is necessary
that nearly the whole strength of the insect
should be concentrated in this segment, to
enable it to dig its way with ease and rapidity
through a resisting medium, while the third
and fourth segments, which bear the organs of
flight, in this species of minor importance, are
smaller than in most other insects. In the
Coleoptera, Geotrupid<Ey which not only
burrow in the earth, but require to be trans-
ported from place to place in quest of food,
the pro-thoracic, and the wing-bearing meta-
thoracic segments are largely developed, and
form a great projxmion of the body, and the
intermediate segment, the meso-thoracic, en-
croached upon by both, is almost atrophied
between them. On the other hand, in the Hy-
menoptera, Lepidoptera, and Diptera, in which
the principal organs of locomotion are the
anterior wings, the meso-thoracic segment is
enormously enlarged, and the pro-thorax and
meta-thorax are reduced to a size of compara-
tive insignificance.

These important modifications of structure,
by means of which every part of the body is
beautifully adapted to the habits and wants of
the individual, and the insect itself becomes an
agent employed by nature to work certain
necessary effects on other parts of Creation, are
accomplished during the metamorphoses by cer-
tain changes in the form of parts of the external
teguments. By this means many insects which in
their naked larva condition scarcely at all differ
in their general external appearance, are made
to assume forms, when they have undergone
their metamorphoses, so totally distinct from,
each other as to be instantly recognisable by the
most unpractised observer. The primary divi-
sion of the body into segments is effected simply
by a duplicature of the external covering. One
margin of the fold is carried over the other, and
a simple telescope articulation is produced.
In this way the body of the larva in its earliest
condition is first divided into its normal num-
ber of segments, and by a continuation of the
same process, as we have before shown, into
distinct regions.

The articulations of the limbs and organs of
manducation are as much the result of changes
in the form of the external surface as the divi-
sion of the body into segments or regions.
The folding, the intussusception, the depression,
or the extension of certain portions of the inte-
gument, when solidified, at the completion of
the metamorphoses, serve all the offices, and
become parts of the different kinds of articula-
tions, which in principle are precisely similar
in insects to some of the more important ones in
the Vertebrata. In the simple approximation of
two surfaces, completely solidified, and allowing
of no motion between them, we discover the
common sutural connexion of some of the
3*2

864

INSECTA.

bones in man. An instance of this occurs in
the upper surface of the cranium of every insect,
in the union of the clypeus posterior with the
epicranium. In another duplicature, one sur-
face of which is rendered concave, and the cor-
responding one opposed to it convex, and
allowing of motion between them almost
•wholly in one plane, we perceive the true
ginglymoid or hinge-like articulation ; while
the small intervening portion of tegument, by
means of which the margins of these surfaces
are connected, becomes thinned and atrophied,
and forms their proper connecting ligament.
Instances of this kind of articulation occur also
in the head of most insects in the articulation
of the mandibles with the cranium, as well as
in the limbs of almost every species. Again,
when a portion of the tegument which covers
the developing organs of locomotion becomes
constricted at the base of the organ, that surface
of the duplicature which is nearest the body
forms a hollow or cup-shaped cavity, into
which the other surface of the duplicature,
rendered convex, is inserted, and in this way
a true enarthrodial or cotyloid articulation is
developed, the connecting ligament between
the two surfaces forming the internal ligament
of the joint, which is thus rendered capable
of most extensive rotation. The ligament thus
formed in every instance is hollow, to allow a
passage for the muscles and other structures
of the limb. Examples of this kind of articu-
lation occur in the coxae or basial joints of the
legs, in the Cerambycida and Curculionida.
Lastly, where the tegument is simply reflected
upon itself, and a sliding motion allowed of,
we have the simple squamous articulation. In
all cases the development of one portion of tegu-
ment takes place at the expense of another, as in
the development of the segments themselves,
and not by the introduction of a new element
in the composition of the part. In this manner,
in accordance with the law of centripetal deve-
lopment as pointed out by M. Serres in the
vertebrated classes, every part of the body is
formed in the so-called invertebrated.

We thus recognise four distinct kinds of
articulation, although several more have been
described by Straus-Durckheim in his excellent
work on Melolontha,* but all of them appear
to be reducible to these primary ones.

These principles will enable us to understand
the cause of the presence or absence of those
structures which form the internal skeleton, and
also the manner in which the limbs of the
imago are developed from the soft and uniform
body of the naked larva. They may also tend
to elucidate one of those hidden and mysterious
processes of nature by which the exterior orga-
nization of the queen or female inmate of the hive
is caused so materially to differ from that of the
so-called neuter or sterile female, influenced as
it is said to be in its whole system by the diffe-
rent quality of the food supplied to the larva
during the first few hours of its existence.

According to the investigations of the most
careful observers, Savigny, Audouin, Mac-

* Considerations, &c. p. 48 et scq.

leay, Kirby, Carus, Straus-Durckheim, New-
man, and others, every segment of the perfect
insect is made up of distinct parts, not
always separable from each other or developed
to the same extent, but existing primarily in all.
It is also believed that the head itself is formed
of two or more segments, but the exact number
which enter into its composition is yet a ques-
tion. So uncertain are the opinions held upon
this subject, that while Burmeister recognizes
only two segments, Carus and Audouin believe
there are three, Macleay and Newman four,
and Straus-Durckheim, even so many as seven.
These different conclusions of the most able in-
vestigators appear to have arisen chiefly from too
exclusive examinations of the head in perfect
insects, without reference to the corresponding
parts in the larvae. It is only by comparing the
distinctly indicated parts of the head in the per-
fect insect with similar ones in the larva that we
can hope to ascertain the exact number of seg-
ments of which it is composed. In the head of
the perfect insect there ought to be found some
traces of all the segments which exist in the
larvae of the same species, and in that of the
more perfectly developed larvae that undergo a
true metamorphosis, there ought in like manner
to be found the rudiments of all the segments in
the least perfectly developed. Now the com-
mon larva of the Dipterous insect, the maggot
of the flesh-fly, is one of the lowest forms we
have yet examined, and we have already seen
that its head appears to be formed of four, and
perhaps even of five segments. This is the
greatest number yet noticed in the head of the
larva of any species. If, therefore, we can
trace the like number in the head of a perfect
insect, we may fairly conclude that this is the
normal number of segments throughout the
class. The head of the great water-beetle,
Hydrous piceus, is remarkably well-fitted for
exemplifying the number of segments of which
the head is~ originally composed, the remains
of four of the segments being distinctly marked ;
and it also affords us a proof of the correctness
of the opinions advanced by Savigny and others,
that the organs of manducation are the proper
articulated members of distinct segments, and
are perfectly analogous to the proper organs of
locomotion.

We shall first describe the parts of which
the head is composed, and then endeavour to
explain the manner in which these parts have
been developed from separate segments to form
the perfect cranium and its appendages. It
has hitherto been customary with naturalists to
designate the head the first segment of the
body, and as every change in the nomenclature
of a distinct part ought always to be avoided,
unless positively required, through fear of
creating confusion, we shall not deviate on the
present occasion from the established mode,
but when speaking of it as a whole shall con-
sider it the first segment, while the aggregation
of segments of which it is composed we shall
designate individually sub-segments, distin-
guishing them numerically in the order in
which they appear to exist in the earliest con-
dition of the foetal larva.

INSECTA.

885

TABLE OF THE PARTS AND APPENDAGES OF THE HEAD.

Fixed parts of the head — external surface,
(a) occiput, including the foramen occipitale and base of the skull, and forming part of

b, epicranium vertex, Kirby epicrane, Straus.

(b 1) ocelli stemmata.

c, oculi corners, Straus.

d, clypeus anterior > nasus, Kirby chaperon, Straus.

</,*clypeus posterior . . . . $ clypeus, Fabricius

w, gula, Kirby piece basilaire, Straus.

e, labrum
f, mandibulae

g, maxillae,
into . ,

Movcable parts of the head.

PI, cardo, Kirby branche transversal e, Straus, insertio, Newman

2, stipes, Kirby . . piece dorsale, Straus ; maxilla, Newman

I 3, palpifer, Newman . .squame palpifer, Straus, bears
divided j 4, the maxillary palpus, h.
"S 5, lacinia, Macleay, Newman ; intermaxillaire, Straus, divided into —

6, galea, Fabricius ; lobus superior, Kirby.

7, lobus inferior, Kirby.

8, unguis, Kirby.

it labium

I

I

t, ligula, Newman; labium, Macleay.

k, the labial palpi.

I, mentum, Macleay; labium, Newman ^ piece prebasi-

m, submentum . . .. stipes, Macleay ; insertio, Newman S laire, Straus.

12, lingua, Newman. . . . hypopharynx, Savigny.

A, antennae . . . .

rscapus. ~\
. . . . < pedicella. > Kirby.
C. clavola. j

Sub-segments of the head.
1st includes labrum and labium.

2d includes clypeus anterior and mentum
3d includes clypeus posterior and submentum
4th, obsolete, orbits and bones of the antennae

5th includes epicranium and gula

The above table exhibits the whole of the
parts yet found in the cranium in the most
perfect order of Insects, the Coleoptera; but it
must be remembered that many of these parts
are less perfectly developed in the other Orders,
and in some of the species have not yet been
discovered.

Commencing our examination of the head
at the posterior part of its upper surface, we
observe that the occiput (a, jig. 369 J is that
portion of its base which is articulated with
the anterior margins of the prothorax. It is
perforated by a large foramen, through which
the organs of the head are connected with
those of the body. It is very distinct in the
Hydrous and most Coleoptera, and in some,
the Staphylinida, Carabida, and Silphida, is
constricted, and extended backwards so as to
form a complete neck; but in others, as in the
Cwculionid&f it is short and hardly distin-
guishable from the epicranium (6), of which it
is the continuation and posterior boundary.

Interior of the head.

f os epipharyngeum,

( os hypopharyngeum anterius.

os hypopharyngeum posterius, z.
( laminae orbitates, w ; and ossicula antenna-
^ rum or toruli, r.
, sutura epicranii, p.
\ os transversum, x.

/ laminae squamosse, s and v ; lames laterales,
J Straus.
(.tentorium, Burmeister, u; arcade, Straus.

The epicranium is the whole of the posterior
and upper surface of the head, bounded pos-
teriorly by the occiput, laterally by the corneae
and sides of the gula, and anteriorly by a tri-
angular suture which extends from the anterior
margin of the corneae to the middle of the
head between the eyes, where its apex unites
with a longitudinal suture which extends along
the median line to the occiput. This trian-
gular suture is a marked character in the head
of many insects, both in the larva and perfect
state, and is of great importance in deter-
mining the number of the sub-segments. It is
very distinct in the larvae of Lepidoptera, and
is as marked in the Melolonthidte and the
Staphylinid(E as in the Hydrous. In some of
the beetles it is indistinctly marked on the
upper surface, but forms elevated ridges on the
interior surface. This is particularly the case
in the Hydrous. In the Dyticus it is more
distinctly marked by a lighter colour of the
skull, while in the common dung-beetles, Geo-

INSECTA.

Fig. 369.

External superior and inferior mtrface of the head of

Hydrous piceus.

Ar antenna ; a, occiput ; b, epicranium ; c, ocn-
li j d, clypeus anterior ; e, labrum ; f, mandibles ;
g, maxilla; h, its palpus; t, ligula; k, labial pal-
pus;' I, mentum; m, submentum ; n, gula; 0, man-
dibnlar ridge.

trupida, its existence is indicated by a slightly
elevated ridge. This suture divides the epi-
cranium from the posterior portion of the cly-
peus (d), the most conspicuous portion of the
head. The proper boundaries of this part
have been ascertained with tolerable precision
in Coleoptera, but do not appear to have been
traced correctly in some of the other orders,
particularly in Orthoptera. The clypeus or
shield, in Coleoptera, is that broad cover of the
anterior surface of the head, bounded poste-
riorly by the epicranium and anteriorly by the
labrum, with which it is freely articulated. It
is the part called by Mr. Kirby the nose, and
by Straus Durckheim chaperon. It appears
originally to be formed of two portions, which
we have called clypeus anterior and posterior,
and which are completely united in some fami-
lies, as in the Lamellicornes, without trace of
their previous distinction, but in others with
slight traces of their former separation, as in
Hydrous, while both parts are distinctly articu-
lated in some of the Dyticida, in which its ante-
rior portion appears to be moveable, and has pro-
bably been mistaken for the whole clypeus, as
has been the case in Orthoptera.* In some
species the shield is curiously excavated, tuber-
culated, or armed with a long horn, as in Copris,
Tyvh*us, and Dynastes, (Jig. 333,) or is minute

* Newman, p. 9.

and inconspicuous as in the Cantharida. The
original division of the shield into two por-
tions in Hydrous appears to be indicated by
two rough excavations situated between the
triangular suture, its posterior boundary, and
the anterior lip. The labrum or upper lip (e)
is the most anterior portion of the upper sur-
face of the head, bounded only on its posterior
margin by the clypeus. It is usually a narrow
transverse piece which has been confounded by
some writers, particularly by Fabricius, with
the clypeus. In some families, Scarabaida
and Lucanidte, it is very minute, but, as re-
marked by Mr. Newman,* cannot be consi-
dered to be in any case entirely wanting, a»
was supposed by Olivier. In those cases in
which it appears to be absent it is concealed
beneath a largely developed clypeus. In many
families it is large and projecting, and often
notched, as in the Carabida and Silphida. It
is also very distinct in the water-beetles. It
forms the anterior boundary of the mouth.

The cornea constitute a great portion of the
fixed parts of the head. The principal of these
(c), the corneae of the true or compound eyes,
are situated on the lateral external surfece of
the cranium, bounding the basilar piece below,
and the epicranium above. They are two large
convex surfaces, generally of a nearly circular,
but sometimes of a kidney-shaped form, divided
into a great number of very minute facets, per-
fectly distinct from each other, each of which is
the proper cornea of a distinct eye. They are
more or less numerous in different insects,
amounting in some to no more than fifty in each
compound eye, but in others to so many as
thirty-six thousand. Thus Lyonet reckoned
eleven thousand three hundred in the eye of the
goat-moth, and Geoffrey more than thirty-six
thousand six hundred in the eye of a butterfly.
Each compound cornea is usually situated im-
mediately behind the external angles of the
triangular or epicranial suture, and is more or
less protuberant in different species, as in
Hydrous and its affinities. This is particularly
the case in the ground-beetles, as noticed by
Dalman,t especially in those which reside near
water or in sandy situations, as the Cicindelida,
&c.; and, as remarked by Mr. Westwood,
these protuberant eyes occur mostly in insects
of rapacious habits. But it roust further be
observed that they occur also in insects which
are not of rapacious habits, but require for
some other purpose an extended field of vision.
This is the case with the males of many species,
and most remarkably so in the male of Lampy-
ris noctilucctythe common glow-worm, in which
the cornea cover almost the whole lateral and
under surface of the head. This insect is well
known to be attracted by the light of the female.
The like occurs in the male of the hive-bee,
and in that of some Diptera, as in the Empida,
which seek their females, and are constantly
found in copula connexos on the wing in the
open air. Again, in the sun-beetles, Cetcniida,

* Paper on the Nomenclature of the Parts of the
Head in Insects, p. 18.
t Entomologist^ T«xt-book, p. 236.

INSECTA.

887

which live on the pollen of flowers, the eyes
are very protuberant. From these circumstan-
ces it may be inferred that all those insects in
which the eyes are either protuberant or very
large are directed by sight alone to some parti-
cular object of their search, whether this be the
female of the species, as with the glow-worm,
&c. or the active living prey, as with the rapa-
cious beetles; and consequently in these in-
stances a more extended field of vision is re-
quired than in those whose object of search is
more easily discovered, or whose means of sub-
sistence is less precarious. In many Coleop-
tera each eye is divided anteriorly by a process
of the epicranium, the canthus, as is particu-
larly the case in the Lamellicornes (Jig. 333).
The extent to which this is developed in dif-
ferent insects varies considerably, and seems to
be greatest in those species which are constantly
engaged in burrowing. Thus, while it is ex-
tended only a little way into the eye in Ceto-
niid<f, it is carried half way across it in Copris,
and in the female of Lucanus cervus, but less
than half in the male; in the genera Ateuchus
and Dorcas more than half way across ; while,
according to Kirby and Spence,* in another
genus, Ryssonatus, it completely divides the
eye into two. In other instances the canthus
is not produced, but the eye is encroached
upon anteriorly by a portion of the epicranium
or by the base of the antenna, which sometimes,
as in the Cerambycidtf, appears as if inserted
into the eye itself. In other families, as in the
Gyrinidte, the middle of the eye is excavated
across its whole surface by a deep furrow,
which gives the appearance of two distinct eyes
on each side of the head. In some insects the
eyes are entirely absent, an instance of which
occurs in one of the Xylophagi, Annomatus
terricola, recently discovered by M. Robert,
near Liege, and an account of which was read
before the Royal Academy of Sciences of Brus-
sels by M. Wesmael, in Oct. 1835. This in-
sect, whose habits are believed to be entirely
subterraneous, is without any external organs
of vision .f

The ocelli, stemmata, or single eyes, are
simple, convex, hemispheric lenses, varying in
number from one to three. They are always
situated, in those insects in which they exist,
on the superior part of the epicranium, poste-
riorly to the triangular suture. They are en-
tirely absent in Hydrous and all Coleoptera
except the Dermestidte, in which there is a
single ocellus situated on the centre of the epi-
cranium, a little posteriorly to the true eyes; in
one of the Pamsidac, and in some of the smaller
Brachelytra ;J but they almost invariably exist
in some of the other orders, as in the Hymen-
optera, Neuroptera, &c.

The under surface of the head is formed chiefly
by the posterior and lateral parts of the gula
(jig- 369, n), which unite with the lateral parts
of the epicranium and occiput. It is bounded
anteriorly by an indistinct suture, and laterally
by the inferior portions of the cornea. In Me-

* Introduction to Entomology, vol. iii. p. 502.
f Fr. Knt. Soc. vol. ii. Proceeding, p. xii.

* Entomologist's Text-book, p. 238.

lohmthid* it is of great extent, and is the
piece basilaire of Straus Durckheim. In Hy-
drous it is excavated in the middle line, on
each side of which are two elevated ridges, the
remains of the basilar parts of the mandibles (<>),
the proper appendages of the fifth sub-segment,
or basilar portion of the head, with which they
have become consolidated. The sub-mentum
(;/?), piece pre-basilaire of Straus, is the most
posterior of the parts that form the under
lip. Straus Durckheim and others appear to
have considered this part as a process of the
immoveable structure of the head, with which
at first it appears to be firmly united. Mr.
Westwood remarks, that although it appears to
be articulated in some beetles, it is immove-
able, and forms part of the under surface of
the head.* We have but little doubt that
it is a distinct piece, and is part of the third
sub-segment of the head, however it may be-
come anchylosed to the gula by the obli-
teration of the fourth in some instances, or
be itself entirely obliterated in others. In
Melolontha it is exceedingly short, but of
great width. In Hydrous it is very distinct,
and the maxillae are articulated to the skull on
each side of its base, as is the case also in
Melolontha and most other instances. It is a
little narrower posteriorly than anteriorly, and
its length is not more than one-half its breadth.
It is articulated anteriorly with the mentum (I);
this is a short transverse plate, in Hydrous
somewhat lunated on its anterior margin, rather
broader than long, but not so short as the sub-
mentum. In Dytictts it is excavated at its
anterior margin, the sides being carried forward
like separate lobes. In this genus it forms
with the sub-mentum, from which it is sepa-
rated only by a slight transverse articulation, a
broad plate, rounded on its edges, and cover-
ing nearly the whole of the under surface of the
mouth ; in some of the Staphylinida it is ex-
ceedingly short and broad, in Melolontha it is
nearly of a square form, but its anterior mar-
gin is acute; in Cetonia aurata, on the contrary,
its anterior margin is much wider than its pos-
terior, or articulation with the sub-mentum.
In Arnphimalla it is quadrate as in Melolontha,
and forms with the palpiger a nearly square
plate. The palpiger, first described by Mr. New-
man^ is not developed in the lip of Hydrous.
In those genera in which it is found, as in Dy-
ticus, it is an articulation which, as its name
implies, bears the labial palpi, and is situated
between the mentum and ligula, of which it
seems to be only a portion. It is subject to
great diversity in size and shape, and in conse-
quence is often confounded with the ligula itself.
It is said to be very distinct in most of the Co-
rabidse, and in Cychrus roslratus, as remarked
by Mr. Newman, it seems at first to have entirely
taken the place of the ligula. In the Staphylinid#t
Goerius, it is much narrower and longer than
the mentum, with which it forms as it were a
con e . I n one of the Endomych id#, Lycoperdina

• Op. cit. 1838, p. 256.

f Entomol. Magazine, vol.ii. p. 82 et seq. .
a Paper on the Nomenclature of the Parts of
Head in Insects, p. 19.

Also

the

888

INSECTA.

bovista, according to the figure by Mr. Curtis,*
it is a. broad oval plate, much larger than either
of the other parts of the labium. This irre-
gularity in its size is very perplexing in examin-
ing the parts of the mouth, since in those cases
in which it is developed to a great extent the
ligula is often so much reduced in size as to
appear entirely absent, and to render it a matter
of consideration whether it would not be better
to consider the palpiger in all cases as only the
inferior portion of the true ligula, since, in a
great number of instances in which the pal-
piger is large, the ligula is very small; and, as
in the instance of Cychrus, is formed only of
minute linear lobes, situated upon and almost
hidden by the palpiger. The ligula (i) is the
most anterior portion of the under lip. It va-
ries as much in shape and size as the palpiger.
In Hydrous it is divided into two lobes by a
slight fissure in its anterior margin, which is
membranous, and covered, as well as its in-
ternal surface, with short smooth hairs. It is
the part which properly represents the true lip,
its internal surface being continuous with the
soft membrane of the mouth. In most of the
Geodephagae it is divided into three linear
lobes, not very unlike in their appearance to the
true palpi. This division into lobes occurs in
most of the predaceous land-beetles. In Ci-
cindelidtE the ligula is very minute, and this is
the case also in some of the Staphylinida. In
the predatory water-beetles, as Mr. Newman
has observed, the ligula is of considerable size,
and this is particularly the case in Hvdrb'us.

The mandibles (jig. 369, f, fig. 370, A), the
true organs of manducation, are two exceed-
ingly large and strong arched jaws. opposed to
each other, and sometimes decussating like the
blades of a pair of scissors. This is the case
in the most rapacious insects, CicindelidfE,
Staphylinida^f 4"c- In tne Hydrous they do
not decussate. They are situated immediately
beneath the clypeus and labrum on each side,
and are connected by a ginglymoid articulation
with the upper and under surface of the head.
The superior external condyle moves in the
articulating surface of the small bone (Jig.
372, <?), a little anterior to the bone of the
antennae (r) and the inferior external condyle
(Jig. 370, f. 3) in the articulating surface
(Jig- 372, y} of the os transversum. In this
insect their form is somewhat like that of
a sickle or garden knife. They are thick
and strong at their base, and hooked at their
apex, and are armed with three projecting,
notched, or double-pointed teeth. The inter-
nal margin of the apex of the mandible is
excavated or grooved, as also are the teeth
along their posterior surface. The object of
this has reference, probably, to the habit of
the insect, the structure of the jaws being
somewhat similar in this respect to that of the
jaws of the more rapacious Dyticus, which is
said to prey upon small fishes and water-
insects. The under surface of the internal
margin of each mandible is covered with soft
villi, and there are four condyles to each
mandible. Those just described perform the

* British Entomology.

A, mandible ; 1, process for 2, extensor tendon ;
3, process to articulate with the inferior surface of
the cranium; 4 & 5, flexor tendon; 6, internal
margin of jaw; 7, bifid teeth.

B, under surface of the maxilla.

C, internal or upper surface ; 1, cardo ; 2,
stipes; 3 & 4, palpifer; 5, lacinia ; 6, galea ; 7,
lobus inferior ; 8, unguis ; 9, retractor maxilla ;
10 & 11, levator cardo.

chief motions ; the others are the middle ex-
ternal condyle (1), which gives attachment to
the tendon of the great extensor muscle, and is
situated between the superior and inferior con-
dyles ; and the internal condyle (b] is situated
on the internal posterior margin of the man-
dible, and gives attachment to the flexor
muscles of the jaw. The internal margin of
the mandible is also rendered concave, and
forms part of the lateral boundary of the epi-
pharynx. From the general structure of the
mandible we at first are lead to suppose that
the habits of the insect are entirely carnivorous,
but it is said to subsist chiefiy upon aquatic
plants, although it feeds with avidity on dead
larvae and aquatic mollusca.* In the truly
carnivorous Coleoptera, the Cicindelid<ey Cara-
bidte, and others, the mandibles are acutely
pointed ; but in those which feed upon vege-
table matter, leaves of trees, See., they are
thick and obtusely dentated, as in Melolon-
tluda. In the generality of species the man-
dibles are always strong dentated organs, but
a few exceptions occur in the Cetoniida, which
feed on the pollen of flowers, and in the
Aphodiadx, which subsist on the recent excre-
ment of cattle, in which their margins are soft
and flexible. They are always the most con-
spicuous parts of the mouth, and differ from

* Westvvood, Introduct. Entomology, vol. i. p.

TNSECTA.

889

the lesser jaws, maxilla, in being articulated
both with the upper and under surface of the
head.

The maxilla, or lesser jaws C/g.370,B,C), are
of very compound structure. They are situated
between the mandibles and labium, and are
employed by the insect to hold its food, and to
convey it to the posterior part of the mouth. They
are each formed of four primary and three or
more accessory parts, when mostcompletely deve-
loped. The primary parts are the cardo or hinge,
thestipes or footstalk, thepalpifer, and the lacinia
or blade. The accessory parts are the galea or
lobus superior; the lobus inferior, and unguis.
The cardo (fig. 370, B, C, 1) is the joint upon
which nearly all the motions of the maxilla
depend. In Hydrous it is a minute trapezoid
or irregularly triangular corneous plate, with an
elongated curved process by which it is arti-
culated with the os transversum on the under
surface of the cranium, and over which the
cardo is articulated like a hinge. In some
genera, as in Staphylinus, it is more elongated,
and this is particularly the case in Melolontha,
whence it was called branche transversale. In
most instances it is as it were wedged in
between the sub-mentum and mandible. It is
articulated at its anterior margin with the
second piece of the maxilla, the stipes (%2),
which forms the outer surface of the organ,
being considered its primary part. It is an
elongated corneous plate, broadest at its articu-
lation with the cardo. It is approximated
along its anterior margin to the squama palpifer
(3), a broad plate which covers the superior
external surface of the maxilla. Immediately
beneath the anterior margin or apex of the
squama is inserted the palpifer (4), a short
cylindrical appendage, which is usually con-
sidered part of the squama, the whole being
together called the palpifer. It supports the
proper maxillary or true palpus, which is re-
markable for its length in the Hydrous. The
lacinia (5), sometimes improperly called max-
illa, forms the internal portion of the organ,
and, as we shall hereafter see, appears in its
earliest condition in the embryo to constitute a
separate organ or appendage, belonging to the
mentum — as the stipes appear to belong to the
sub-mentum — but which in the course of deve-
lopment becomes approximated to the stipes to
form part of the maxilla of the perfect insect.
Like the stipes, it is a broad corneous plate,
which forms the greater portion of the under
surface of the maxilla, and is articulated with
the cardo only by a small portion of its base.
On its upper surface, which forms a great part
of the sides of the mouth, it is soft, membra-
nous, and covered with fine hairs. It gives
origin at its anterior truncated extremity to the
accessory parts of the maxilla, the lobus supe-
rior and inferior. The lobus superior, or galea,
is a thick, double-jointed organ (6), densely
covered at its anterior margin with stiff reddish
hairs. It is articulated with the external an-
gle of the lacinia, and covers the lobus inferior,
which is articulated with the internal angle,
and on this account, more particularly in
Orthoptera, is called the galea or helmet. It
is used by this and other insects as a palpus,

or feeler, to touch and convey food to the
mouth. The lobus inferior is a short quadrate
joint (7), articulated with the internal angle
of the lacinia, of which it forms the proper
Continuation. At its superior extremity is a
minute articulated claw (8), densely covered
on its upper surface with long stiff hairs, as is
also the whole of the internal margin of the laci-
nia itself,which forms the lateral boundary of the
mouth, and is continuous with the soft lining
of the pharynx. The maxillary palpi (A) are
two very long flexible organs, composed each
of four joints. The palpifer, upon which they
are situated, is a short joint or tubercle, in-
serted at the anterior external angle of the
maxilla, between the angle of the lacinia and
the plate which covers the superior surface of
the maxilla (3), and of which it forms a part,
but from which in this insect it appears quite
distinct. The first joint of the palpus is ex-
ceedingly short, so as to allow of extensive
motion to the organ in every direction, while
the second is much longer than in most other
insects, and, when the palpus is retracted,
forms with the third joint a distinct elbow or
bend. The third and fourth joints are also of
great length, so that the insect is enabled to
protrude the organ to a great distance. The
labial palpi (jig- 369, /:) are much shorter than
the maxillary. The first two joints are very
minute, the second being partly hidden within
the first, but the third and fourth are long and
projecting, but not so long as those of the
maxillary palpi.

From all we have been able to observe, the
office of the maxilla appears to be of a two-
fold kind, and of greater importance to the
insect than that of the mandibles themselves.
The chief office is that of seizing and retaining
the food within the mouth ; and the secondary
that of assisting the mandibles in comminuting
it before it is passed on to the pharynx. Con-
sequently all the parts of the maxilla are sub-
ject to great variation of form ; and in the dif-
ferent tribes of Coleoptera, as in the other
orders of insects, each particular form is
adapted to the kind of food on which the in-
sect subsists. In Melolontha, in which the
four primary parts, the cardo, stipes, palpifer,
and lacinia, were first accurately distinguished
by Straus Durckheim,* the maxilla is a thick
obtuse organ, with the cardo, which is less
completely developed in Hydrous than in most
other insects, forming a broad transverse piece,
the stipes a short and triangular one, the pal-
pifer also nearly triangular, and the lacinia,
which, as Straus has remarked, is always con-
tinuous with the pharynx, nearly also of a tri-
angular form, and together constituting a thick
compact organ, with its inner angle, the lobus
inferior in other insects, forming a strong pro-
jecting inarticulated tooth, and its external,
articulated with a short thick galea, armed
with three obtuse points, which probably serve
the office of teeth for masticating the paren-
chymatous food of this species. This form of

* Considerations Generates sur 1'Anatomie Com-
paree des Animaux Articules, par Hercule Straus-
Durckheim, 1828, p. 68, pi. i. fig, 8.

890

INSECTA.

the maxilla and galea seems more peculiarly
adapted to the phytophagous feeders, since in
the true carnivorous insects, Cicindtlid<?, tiger-
beetles, and the larger Carabida, ground-bee-
tles, the maxilla is more elongated, the inter-
nal lobe, or apex of the lacinia, is more acute,
and often armed with a sharp hook, and the
galea assumes the form of a distinct palpus,
shorter but similar in appearance to the true
maxillary palpus. This is more manifestly
the case in the tiger-beetles, in which the galea
is a distinctly double-jointed palpus, placed
on a feeler-bearer, and the lacinia is armed
with a long sharp hook, evidently more adapted
for seizing and piercing its living food, like the
canine teeth of carnivorous quadrupeds, than
for comminuting it like the strong tuberculated
galea of the vegetable-feeding Melolontha, or
the tuberculated teeth of herbivorous quadru-
peds. The office then of the galea, in dis-
tinctly carnivorous insects, is simply that of a
palpus or feeler, and in accordance with this
view we find that in the tiger-beetles it is
longer than the inferior lobe, or hooked por-
tion of the lacinia. In the ground-beetles
Mr. Newman has remarked that it is shorter
than the lacinia, but, in the generality of the
tribe, we have also found it longer, as in the
rapacious Cicindelidae, particularly in the lar-
ger Carabidtf, and this is also the case in some
of the Harpalida, particularly in one species,
Zabrm gibbus, which is known to be a vege-
table feeder. This form of the galea, however,
seems more peculiarly to belong to the carni-
vorous insects, as it is also found in the Dyti-
cidae, but not, as we have seen, in the nearly
allied but far less rapacious Hydrophylid<p..
On the other hand, in most insects which feed
entirely on vegetable matter, the galea is of a
more obtuse form, and is less distinct from the
other parts of the maxilla than in the rapacious
insects. Thus in the greater number of the
true vegetable feeders the galea is short, thick,
and densely covered with hair. This is the
case not only with the maxillae, but also with
the mandibles in those insects whose food is
the pollen and perhaps also the honey of
flowers, as in the Cetoniida, and also in the
Geotrvpida and other Scarabteidx, which feed
upon soft decaying vegetable matter. In the
Cerambycida, as in the rare insect Monochamus
sarhrrf in the Lepturida, which are found
upon umbelliferous plants feeding on the pollen
and honey ; and in the stag-beetle, Lucanus
cervus, which subsists on the sap that flows
from the wounded bark or roots of trees, the
galea is always densely covered with hair, and
sometimes elongated to a considerable extent,
as in the stag-beetle. In those species which
are purely phytophagous, as many of the
Galerucidtf and Chrysomelidee, which feed on
the parenchymatous structure of leaves, both
the galea and lobus inferior are short, obtuse,
and covered with stiff hairs,while in the Core incl-
lid<E that very much resemble the latter insects,
but are carnivorous feeders, the galea is longer
and distinctly jointed, and resembles the same
part in Hydrous, being still covered with hair.

* Curtis's British Entomology, pi. 219.

This is also the case in the common meal-
beetle, Tenebrio rnolitor, which belongs to a
family of less distinctly vegetable feeders.
From these facts we are inclined to believe
that the structure of the maxilla has much
closer connexion with the kind of food and
habits of the insect than that of either the
labium or the palpi. The latter organs, how-
ever, are subject to great variation in the form
of the terminal joint, which in some species is
much dilated and shaped like a hatchet, as in
the common lady-bird, Coccinella, while in
others it is acute or obtuse. The number of
joints is usually four, and it has been sup-
posed that there are never more, either in the
maxillary or the labial palpi, in any Coleop-
terous insect, but the Rev. Mr. Kirby* has
mentioned an instance in which there appeared
to be an anomalous condition of the maxillary
palpi, in this respect, in one of the Geode-
phaga, Sericoidiu bembidtoides, K. In one of
the palpi in this insect there was a fifth joint,
retractile within the fourth. Mr. Kirby sug-
gests that since the fifth joint was not apparent
in the other palpus, it may perhaps have been
a false joint, produced by an effort of nature
to repair a mutilated organ, but at the same
time observes that if this were the case it is
the only instance he has met with in true in-
sects of the reproduction of a lost organ.

The antenna constitute the remaining move-
able parts of the head (fig. 369, A). They are
occasionally absent in the larva, but never in
the perfect state in any insects. They are two
jointed organs, attached to the head by a dis-
tinct and freely moveable articulation, in some
insects near the middle of the front part of the
head, but in Hydrous and most Coleoptera
on each side immediately anterior to the cor-
neae, at the extremity of the epicranial suture,
but never, so far as we are aware, in the epi-
cranium itself. They are subject to much
diversity of form, on which account they have
been employed by naturalists as affording cha-
racteristic distinctions of different families.
They have been divided into several parts, only
three of which appear to be generally applica-
ble. These are the scapus, (Jig. 371, M 1), pedi-
cella (2), and clavola (3).f The scapus, or
basial joint, is usually very long, and often the
most conspicuous part of the antenna. It is
connected with the torulus, or part upon which
it moves, by means of a ball and socket arti-
culation, beneath the external margin of the
clypeus. The second joint, pedicella, in Hy-
drous, as in almost every species, is a minute
and nearly globular articulation, which allows
of the freest motion, and supports the re-
maining portion of the antenna, the clavola,
which forms the chief part of the organ, and
is that which varies most in general structure.
When each succeeding joint of the clavola is
gradually diminished in size from the base to
the apex of the organ, as in the Gryllida,
Achetida, and BUitiidec, Jig. 342 and 343, the
antenna presents its simplest condition, and is

* Fauna Boreali-Americana, vol. iv. Insect?,
page 15. pi. i. fig. 2.

t Kirby and Spence, p. 515, et scq.

INSECTA.

891

^ Fig, 371.

\

Antennae, from Burmeuter, Meigen, Paty, and Hope.

M, antenna of Melolontha folio; 1, scapus ; 2,

pedicella; 3, clavus ; 3*, the laminae.

called setaceous (fg. 371, A), but when, as in
some of the Locwtida, each joint is much smal-
ler than the preceding and is angulated at its
sides, the whole forming a sword-like organ,
it is called ensifitrm (B). When all the joints
of the clavola are of uniform thickness, as in
the Carabida, (fg. 329,) the antenna is said
to be filiform (Jig. 371, C), but when the joints
are of equal size, but are globular or rounded,
as in the Tenebrionida (Jig. 340), it is called
moniliform (fg. 371, D). When the joints,
as in some of the Elaterid<e, (fg. 334,) ap-
pear like inverted triangles, with the inner
margin more produced than the outer, they
are said to be serrated (fg. 371, E), and
when, as in the Prionidx, the acute base of
each joint is inserted into the middle of the
broad apex of the joint behind it, imbricated
(F). When every joint is developed on one
side into a spine or process, tlie organ is said

to be pectinated (G) ; and when a spine or
process is developed on each side of the joints,
bipectinated (H). In like manner it is called
plumose(N ) when each joint producesone or more
rami which are themselves minutely pectinated,
as in many of the Bornbycida; and when, as in
Hemirrhipusjlabellicornis and other Elaterid<r,
each process from a joint is flattened, and is
nearly as long as the whole of the succeeding
joints taken together, and the whole form a
fan-shaped organ, the antenna is called Jlabel-
Itite (I). But when, as in the true beetles,
Pentamera, the clavola ends in a true capi-
tulum or knob, it is said to be clavate (K), or
capitate (L), according as the knob is gra-
dually or suddenly formed at the extremity of
the organ. In Hydrous the capitulum exists
in that form which is designated perfoliatey in
which the joints of the club are separated a
little from each other by a minute foot-stalk.
This form exists also in the Necrophori, and
in a less degree in the clavated antennae of other
Silphidte. It is in some of the Lamellicomest
the Scarabaida, Geutrvpida, Dynastida, and
Melolonthida, that the antennae reach a degree
of completeness which seems to indicate the
real use of the organs. Thus in the Melolon-
thidit (M), the capitulum is divided into seven
laminae, which may either be applied closely
together, or be widely expanded at the plea-
sure of the insect. In the Dynastida and
Geotrupida the capitulum is formed of only
three laminae, the two outer ones being convex
externally, but flat on their internal surface,
while the intermediate one is flat on both sur-
faces, the flat surfaces of each being more
delicately organized than the hard corneous
exterior. A similar structure exists also in the
Scarabaida. When the insect is in motion
the antennae are stretched out, and the laminae
are expanded to their fullest extent, but by
many species are immediately retracted on the
occurrence of any loud or sudden noise.

These are the usual forms of the antennae,
but in some species they are subject to much
greater variation. Thus, in the remarkable
order Strepsiptera (fig. 347), each antenna has
a distinct lobe at its base. This is also the
case in some of the Muscida (N), in which the
filamentous portion of the antenna represents
the true clavola, and the club-shaped portion
of the organ is simply an appendage. A simi-
lar deviation from the usual structure occurs in
some Coleoptera, more particularly in the smal-
ler water-beetles. Thus, in the Gyrinida, the
true pcdicelUi is developed into a large ear-
shaped cup, which nearly covers the clavola.
In another insect, Globaria Leachii, LATR.
very beautifully figured in the recent work
of the Rev. F. W. Hope,* the pedicella,
(O, 2) instead of being a small rounded joint,
is elongated like the scapus (1), while the cla-
vola (3) ends in a large capitulum, attached
laterally to the base of the fifth joint and di-
rected backwards. These are a few of the
variations which occur in the form of these

* The Coleopterist's Manual, part ii. tab. 3,

fig. 6. 1838.

892

INSECTA.

curious organs, the necessity of which it is
difficult to understand.

The function of the antennas has been a
subject of much dispute amongst naturalists,
some contending that it is simply that of feel-
ing, others that of smelling, others again that
of hearing, and lastly others that of a sixth
sense unknown to vertebrata. Our own ob-
servations lead us most decidedly to the con-
clusion that the primary function of the an-
tennae is that of hearing or feeling the vibra-
tions of the atmosphere, while an additional
function possessed by the antennae of many
insects is that of common feeling or touch.
We have endeavoured to support this opinion
by facts and experiments detailed in a paper
on the use of the antennas, which was read
before the Entomological Society of London
in the beginning of 1838, but which has not
yet been printed. First as regards the employ-
ment of the antennae as olfactory organs, there
seems in their anatomical structure the most
decided evidence that they cannot be designed
for such purpose. In every instance in verte-
brata, the faculty of smelling is situated in a
delicate mucous or soft surface, and in no
animal that we are aware of has it ever been
found to reside in a dry horny covering, or in
a tense membranous structure, while, on the
contrary, that of hearing is constantly depen-
dent upon an elastic membrane, or other part
sufficiently delicate to be affected by the vibra-
tions of the atmosphere. If therefore the sense
of smelling be dependent, as it appears to be,
upon a moist or lubricated surface, it cannot
reside in the antennas, since the exterior sur-
face of these organs is in every instance formed
of a dry hardened covering. On the other
hand, if the perception of sound be depen-
dent upon the elasticity of a part, and its capa-
bility of being affected by the vibrations of the
air, the structure of the antennae is in no in-
stance unadapted for the performance of this
function. It seems improbable that the office
of the antennae is simply that of touching or
feeling other objects, by direct contact, as sup-
posed by some naturalists, from the circum-
stance that in certain insects these organs are
much too short to be so employed, being in
many species, as in the LibeUulida and Cica-
diida (fig. 353), shorter than the head itself.
But that they are so employed by some insects
is indisputable, particularly by the Blattidtf,

and most of the Hymenoptera.
The Gryllidse, when sipping water from the
channelled surface of a moistened leaf, con-
stantly feel about with the antennae ; and the
honey-bee, when constructing its cells, ascer-
tains their proper direction and size by means
of the extremities of these organs, while the
same insect, when evidently affected by sounds,
keeps them motionless in one direction, as if
in the act of listening. Another circumstance
which favours the opinion that they are audi-
tory organs is their greater development in the
males of some species than in the females, as
in the bipectinated antennas of many moths,
and the lamellated ones of the Melolonthida.
The structure well known to exist in the

Crustacea,* the bony tubercle covered exter-
nally by a tense membrane, and communi-
cating internally with a membranous vesicle,
situated at the base of the antennae, sufficiently
proves that in those animals the antennas are or-
gans of hearing, and is not an inadequate reason
for regarding them as ministering to the same
function in insects. But the fact of the ex-
istence of a small circular space discovered by
Treviranus, at the base of each antenna in the
Bluttida, (fig. 373, f) which are noted for
extreme acuteness of hearing, and which space,
as in Crustacea, is covered by a membrane, is
an additional reason for considering the func-
tion of the antennas in insects analogous to
that of the corresponding organs in those
animals. Thus then almost every circumstance
connected with the antennas leads us to the
conclusion that these are the proper organs of
hearing, while their occasional employment as
tactors or cerebral feelers is not incompatible
with the exercise of that function, hearing be-
ing in reality only a more exquisite sense of
feeling.

Fig. 372.

Interior of the tipper and under surface of the

head of Hydrous.

df clypeus ; e, labrum; g, maxilla; h, its pal-
pus ; t, labium ; k, labial palpus ; p, sutura epi-
cranii ; q, cotyloid cavity ; r, torulus ; s, v, laminae
squamosae ; t, laminae posteriores ; u, tentorium ;
to, laminae orbitales ; xt os transversum ; y, arti-
culating cavity for the inaudible \ x, os hypopha-
ryngeum.

Internal parts of the head. — On the interior
surface of the superior portion of the cranium
of Hydrous piceus (fig. 372), the insect we have
selected for our purpose, is a thick horny ridge
(p\ extending along the middle line from the

* See vol. i. p. 768, art. CRUSTACEA.

INSECTA.

893

occipital foramen to about midway between the
cornea, where it becomes much thickened and
expanded, and then divides into two portions,
which pass forwards and outwards m a dia-
gonal direction, to the anterior margin of each
cornea. These ridges on the internal surface
exactly correspond to the faint indication of the
epicranial suture on the external. They serve
for the attachment of muscles, and divide the
epicranium from the clypeus posterior. At
the external angles of these ridges, immediately
anterior to the corneae, are two articulating apo-
physes, the most external of which, the torulus
(r), is smooth and rounded on its anterior sur-
face, and articulates with the broad concave
extremity of the scapus} or basial joint of the
antennae, and the external one (<?), (cuviti coty-
loid, STRAUS,) is smooth, rounded, and con-
stricted in its middle, and articulates anteriorly
with the superior external condyle of the man-
dible, and posteriorly with a process of the
lamin<£ i>quamos(£ (s), which support and pro-
tect the brain, and are united with other la-
minae (v) (hunes laterales, STRAUS,) which
arise from the inferior surface of the cranium.
The torulus (r) is attached externally to the
most anterior portion of a thin broad lamina,
the orbital plate (w}, which extends backwards
to the posterior angle of the cornea, in an
arched direction, separating the cavity of the
orbit from the interior of the cranium, with
which it communicates only by means of a
round foramen for the passage of the large
optic nerve and its tracheae. The superior half
of this plate consequently belongs to the epi-
cranial, and the inferior to the basilar portion
of the skull. Immediately anterior to the epi-
cranial suture is situated the clypeus (rf), the
middle portion of which is smooth and slightly
concave, and forms the covering of the ante-
rior part of the head. On either side it has a
smooth broad inflected margin, which is not
included within the interior region of the head.
At the anterior margin of the clypeus is arti-
culated the freely moveable labrum (e\ the
under surface of which is smooth and shining,
and gives no attachment to muscles, excepting
along its posterior margin. The ridge of the
epicranial suture is developed to a greater ex-
tent in the head of Hydrous than in any other
species we have yet examined. Its perfect
correspondence with the faint indication of the
suture on the exterior of the head clearly in-
dicates the boundary of the epicranium, and is
of very great importance, as we shall hereafter
see, in enabling us to determine the number
of segments of which the head is composed.
This suture exists in every species we have
examined, more or less developed in different
individuals. Its existence appears to have
been entirely overlooked by Straus-Durckheim
in the head of Melolontha, in which, indeed,
it is almost obliterated externally, but when
the cranium is well cleansed, and then ex-
amined by means of transmitted light, a trace
of it may still be observed, and its situation
internally is indicated by a shallow triangular
furrow, which extends backwards from the
anterior portion of each orbital plate to within

a short distance of the occipital foramen in the
middle line, the longitudinal portion being
exceedingly short. But in the larva of the
same insect the suture is very distinct on
the exterior of the epicranium, and the ridges
corresponding to the suture are developed on
the interior. Anterior to this suture in the
same larva is a triangular piece, which is
bounded in front by a freely articulating plate,
the anterior clypeus. It is the part correspond-
ing to this, and which is consolidated with the
true clypeus in the head of Hydrous, as in-
dicated by the diagonal depressions before
noticed on the external surface of the head,
which we shall distinguish in all insects as the
clypeus anterior.

It will thus be found that in some insects
the clypeus anterior and posterior have hitherto
been confounded under one name, and in
others the clypeus posterior and epicranium.
We believe, however, that these are distinct
parts in all insects, but are less readily distin-
guished in some than in others. The upper
surface of the head is thus shewn to be formed
of at least four clearly indicated portions, both
in the larva and perfect insect. In the larva of
melolontha there is also a slight indication of a
.fifth, segment, of which the antennas, or ante-
rior prolongations of the spinal columns, are in
reality the proper appendages. The indication
of this segment exists in a triangular line,
parallel with, but a little anterior to, the suture
behind the clypeus posterior, and in the space
included between it and the epicranial suture
the antennae seem to be inserted. But al-
though we believe in the existence of the fifth
segment in all insects, it must be acknowledged
that it is not easily demonstrated. Four seg-
ments are, however, readily detected, yet in
some species one of these has almost disap-
peared. Thus in Geotrupes stcrcorarius, the
epicranial suture has become very indistinct on
the upper surface of the head, and the ridges
are entirely absent on the interior, as in melo-
lontha, while the clypeus posterior exists only
as a narrow triangular space, bounded by the
suture posteriorly, and anteriorly by a ridge cor-
responding to the boundary of the proper an-
terior clypeus on the exterior of the head ; the
labrum also, as in all insects, being quite dis-
tinct. In Lucanus cervus, in which the head
has reached its maximum of development, and
is much broader than the pro-thorax, there is no
indication whatever of the triangular suture in
the male, all the parts of the head being firmly
consolidated together. But in the female there
is a faint depression internally, as in melolon-
tha, and the trace of a corresponding line is
apparent in some specimens externally. In
some specimens of Melue cicatricosus there is a
distinct indication of the suture externally, ex-
tending from the occipital foramen to near the
middle line between the eyes, while internally
the ridge is distinctly elevated ; but we have
not been able to trace the clypeus posterior,
which may be supposed to have merged in the
largely developed epicranium. In Blaps mor-
tisaga the epicranial suture is usually distinct
on the upper surface of the head, posterior to

894

INSECTA.

the cornea;, but the ridge is absent, while the
transverse ridges between the two portions of
the clypeus are distinct, and also their corres-
ponding sutures on the exterior. On the other
hand, in the large Buprestis chrysis, the longi-
tudinal portion of the epicranial suture is very
distinctly marked on the upper surface, and ex-
tends as fax forward as the middle between the
corneae, while internally the ridge is so largely
developed that it extends downwards into the
cavity of the head, like the ossified falx in the
head of some Carnivorous Mammalia, partially
dividing the posterior region of the head into
two halves. But the clypeus anterior and pos-
terior are so solidified together, and united with
the epicranium, that they are not easily distin-
guished. This is also the case in the rapacious
ground-beetles, Cicindelida, in which all the
parts of the cranium are completely united, and
the true clypeus is reduced to a narrow trans-
verse plate, with which the labrum is freely ar-
ticulated. But in the rapacious water-beetle,
Dyticus marginalia, although the ridge of the
epicranial suture is wanting, as in Cicindetida,
the suture itself is remarkably distinct, and the
anterior and posterior clypeus are well marked,
and are very clearly seen owing to their thin-
ness and translucency, when examined by
transmitted light.

The inferior surface of the head affords us
equal reason with the superior, for believing
that this part of the insect is formed of an ag-
gregation of several segments. We shall ex-
amine them more particularly when speaking
of its development. On its interior surface
are parts which tend much to confirm the opi-
nion. In Hydrous piceus on each side of the
occipital foramen there arises a strong bony
plate, lamina posterior (£), which, bending a
little towards the median line, extends across
the basilar portion of the skull, as far as the os
transversum (.r), with which it is united. At a
short distance from the occipital foramen the
lamina of one side is connected with its fellow
of the opposite by a narrow bony arch (u),
which has been called by Straus Uarcade, and
by Burmeister, who has described it in Dyticus,
the tentorium. The two laminae beyond this
are expanded upwards and laterally, and uniting
anteriorly by a thin process form a cradle, or
bed, which, as Straus and Burmeister have re-
marked, supports the first sutwesophageal gan-
glion, while the two lamina postertores inclose
between them, as in a canal, the anterior por-
tion of the spinal cord, which passes under
the tentorium in its exit from the cranium
through the occipital foramen. Each of these
expanded portions of the laminae are united by
their superior angles with a narrow process (s),
which articulates, as before noticed, with one
of the apophyses of the upper surface or vault
of the cranium. The orbital plates (w) above
described are continued around the margin of
the cornea?, and form the inferior lateral boun-
<lary of the basilar portion of the cranium.
Between the anterior margins of the corneas,
extending across and dividing the basilar
part of the skull from the sub-mentum, is a
thick elevated ridge, the os transversum (x).

On its anterior border the os transversum is
connected with a minute bony ridge, which ex-
tends forwards on each side of the sub-mentum,
and it has also two articulating surfaces. The
first and most internal of these (.r) is situated
close to the base of the sub-mentum, and is that
with which the hinge of the maxilla is articu-
lated. The second is situated more externally,
between this and the margin of the cornea. It
is a deep smooth cotyloid cavity (?/), which re-
ceives the external inferior angle of the man-
dible, and is separated from the articulation
for the hinge of the maxilla by an elevated
tubercle. Externally the base of the skull is
connected only by an indistinct suture with a
quadrate plate, the sub-mentum, which was sup-
posed by Straus-Durckheim to form a process
only of the basilar piece in melolontha, and
was called by him the pre-basilaire. We have
already seen that it is part of a distinct segment,
and seems to correspond to the clypeus poste-
rior of the upper surface. At the anterior mar-
gin of the sub-mentum, or rather extending
backwards upon that segment from the men-
turn, are two broad diverging laminae (z),
which support the fleshy pharynx and tongue,
in which respect they are similar in office to
the proper hyoid bones of vertebrata. They
serve as means of attachment for some of the
muscles of the pharynx, and are connected
with similar laminae that cover the upper sur-
face of the pharynx, and seem to be connected
with the clypeus, as in the Lucanus cervus.
The mentum, like the sub-mentum, to which it
is attached, is broad, quadrate, and supports
the diverging laminae which form the floor of
the mouth, and it also affords an attachment for
some of the muscles of the tongue and labial
palpi. The ligula, or most anterior portion of
the labium, is densely covered on its upper
surface with hairs. It is divided in the median
line into two halves, which, when developed to
a much greater extent, as in some other insects,
take the name of paraglosste.

The general structure of these parts is similar
in most Coleoptera, but in some species there
is considerable variation of form and relative
size, owing to the greater development of one
part than of another. Thus in Lucanus cervus,
(l/ig.388,) in which the whole head is developed
to its greatest extent, and the epicranial and
basilar regions, with the mandibles (./*), have
very far exceeded their usual proportions, the
labrum is very minute, and soldered to the
clypeus (d), and the maxillae (g) are reduced to
small palpiform organs. Internally, the pos-
terior laminae (t) do not extend forward to an os
transversum, but are short, strong, triangular
plates, which, instead of being connected, as in
Hydrous and Melolontha, by an arcade, or ten-
toriura (u), support a double ring, or annul us,
like the ring of a vertebra, through which the
nervous cord passes before it arrives at the
occipital foramen. In Geotrupes stercorarius
there is a like annular form of the same parts,
but the laming squamoste, which are absent in
Lucanus, are thick and strong, and form a
complete cradle for the supra-oesophageal
ganglion, la like manner a similar change ia

INSECTA.

895

the form and relative size of parts of the head oc-
curs in the hog-beetles, Curculionida (Jig. 337),
in which the head is elongated forwards, and
the mouth is situated at the extremity of a long
rostrum or beak. This is occasioned by the
narrowing and extension forwards of the clypei,
and the parts corresponding to them, the men-

turn and sub-mentum. This change is carried
to such an extent in some species, as in Liparis
Germanus, that the antennae are also carried for-
wards, and appear as if situated at the sides of
the mouth. That this is the manner in which
the change of form is effected is proved by the
circumstance, that the basilar and epicranial
regions in this insect do not exceed a fair pro-
portion, as compared with other insects; while
the triangular suture, which always divides the
epicranium from the posterior clypeus, exists in
its usual situation on the part between the
eyes ; and the labrum, which is very distinct, is
freely articulated with the anterior margin of
the clypeus. The effect of this elongation of
some parts of the head and mouth is the neces-
sarily small size of others, and consequently we
find that the mandibles, which are so enor-
mously large in Lucanus, are reduced almost to
their minimum in the Curculio ; because, al-
though the elongated form of the head is admi-
rably adapted to the habits of the insect, in
boring deeply into hard substances, it is insuffi-
cient for the support of large and powerful
organs, and its extent of surface is too limited
to afford adequate room for the muscles neces-
sary for their employment. Wherever large
and powerful organs exist, the parts to which
they are attached are enlarged in like manner.
Thus we invariably find that in those insects in
which the mandibles are large, the whole head
is either short and wide, or its posterior por-
tions, the basilar and epicranial regions, to
which the muscles of the mandibles are at-
tached, greatly exceed those of the anterior.

The parts observed in the head in Coleop-
tera are equally apparent in Onhoptera. In
this order the head is placed vertically on the
pro-thorax, without any constricted portion or
neck, so that the extent of the occipital region
is greatly reduced. The epicranium in some
species, Locustid<e, $c. is broad behind, but
narrowed in front, where it is bounded, as in
other insects, by the clypeus posterior, and la-
terally by the cornea? and sides of the head, of
which it forms a part. In this order the
ocelli, or single cornea?, which are found only
in a few solitary instances in Coleoptera, exist
in most of the families. They are situated in
the anterior portion of the epicranium, and
form part of its surface, whether placed on the
vertical portion of the head, or more anteriorly
near the clypeus. In the osculant family,
Blattida, the epicrauium is exceedingly
shortened, but retains along its vertex a trace of
the epicranial suture, which is scarcely ever
absent in the insects of this order. It is very
distinct in the common house-cricket and mole-
cricket, Achetida; (Jig. 342), in the Gryllida:
and Locustida. In the mole-cricket it some-
times appears as if wholly obliterated, but is
always seeu in the pupa if care be taken to

remove the down with which it is sometimes
covered. Its apex is situated in the middle
line between the ocelli, and on each side it
passes down to the insertion of the antennae. It
is in this order that the suture is particularly
useful in indicating the boundary of the pos-
terior clypeus, the extent of which in Orthop-
tera appears hitherto to have been overlooked.

Fig. 373.

Head of Blatta Americana.

A, antenna ; t, tympanum ; 1 1» socket for the an-
tenna, covered with membrane ; dd, clypeus,
anterior and posterior; *, lingua; •**, paraglossae.
( Other letters and figure* at in Hydrous. )

In the epicranium of Blatta (Jig. 373), the
suture is almost obliterated, being only disco-
verable by aid of the microscope, but on careful
inspection it is seen to end at a point opposite
to the middle of the superior portion of the
corneae, where it forms the apex of the triangle,
which enters, on each side, the anterior margin
of a circular space covered with a tense mem-
brane, the tympanum (f), which is situated, as
observed by Treviranus, a little behind the in-
sertion of the antennse. These organs are also
inserted in a rounded space covered by a mem-
brane. From these points the suture becomes
obliterated, but seems to pass in the direction
of the anterior boundary of the corneae to the
base of the mandibles. The clypeus posterior
(d) thus appears to form the greater portion of
the front or face of the insect, and is united by
a transverse freely articulating membrane, ex-
tending across from the base of each mandible
with a short transverse plate, the clypeus ante-
rior (d), which has hitherto been looked upon
as the true clypeus. In the common green
grasshopper, Acrida viridissima, the boundary
of the posterior clypeus is at the most anterior
part of the head immediately between the an-
tennae, the suture extending, as in other in-
sects, to their base. The clypeus anterior is a
short transverse moveable plate, and is articu-
lated with the labrum (e\ which is also short,
transverse, and freely moveable upon the cly-
peus anterior. This moveable condition of the
anterior clypeus and lip has not a little puzzled
entomologists. Mr. Newman* has remarked
that " the lip and shield move simultaneously

• Op. cit. p. 9.

896

INSECTA.

with the mandibles in mastication," and that
" this is a departure from a general law of
nature, and its occurrence is well worth re-
marking; as the motion of the shield might in-
duce an observer to suppose it the lip, which
would consequently become a new and super-
numerary elementary part." Thus, then, the
motion of this part in Orthoptera is considered
as an anomalous condition, but the same thing
occurs in Coleoptera. In Dyticid*, the cly-
peus is freely moveable, as well as the labrum,
and probably this mobility has reference to the
rapacious habits of the insects.

The inferior surface of the head in Orthoptera
varies a little from the type of the Coleoptera,
although it is formed, as in that order, of four
distinct parts. The gula, or basilar region (m),
which includes part of the occipital foramen, is
a broad transverse plate, rounded at its lateral,
and concave at its anterior and posterior mar-
gins. In the mole-cricket, as in most of the
'beetles, the true gula is well developed be-
tween the occipital foramen and sub-men-
tum, and in that insect is of a trian-
gular shape, with its apex directed backwards.

Fig. 374.

Under surface of mouth of Blatta. Figures as
before.

But in the Blattida (fig. 374, m), the sub-men-
tum and gula appear to have been closely
united, without trace of their former distinc-
tion, and the mentum (I) is short, transverse,
and articulated with the palpiger and ligula
(i). From the complexity of parts into
which the ligula is divided, we consider it
better, as before remarked, to omit any parti-
cular description of the palpiger, which, Mr.
Newman states, is situated between the proper
ligula and mentum. In Blatta the ligula is
divided into six distinct parts. To two of these
(*) are attached the labial palpi, and they ap-
pear to be the palpiger as described by New-
man. From the upper anterior margin of
these, nearest the median line, arise two short
lobes, covered partly on their exterior margins
by two larger ones, the paraglosste (* *),
which become of much importance in the
mouth of Hymenoptera. In the mole-cricket
the ligula is divided only into four lobes, all of
which are exceedingly narrow, and very much
resemble palpi. In some of the Locustida,
the labium is simply divided in the median
line as in Hydrous. The true ligula or tongue
(fig. 374*) in most of the Orthoptera is a
soft projecting fleshy body, like the tongue of

other animals, and is situated above the men-
tum and sub-mentum, within the mouth of
which it forms the floor and passage to the
pharynx. In Blatta it is narrow and elon-
gated, and projects as far as the middle of the
ligula, and it is even more largely developed in
the Locustida and Achetida. In the maxilla
we recognise the same parts as in Coleoptera,
with but little variation of form except in the
galea and lacinia. The lacinia (5) is usually
elongated, and furnished with a sharp hook
bipid at its apex. In Achetida and most of
the vegetable feeders it is strong and much
bent at its extremity, but in the omnivorous
Blattida it is also sharpened to a cutting edge
along its inner margin. It is in this order of
insects that the secondary appendage of the
maxilla, the galea (6), is most fully developed,
and covers the lacinia so completely as to serve
the office of a shield or helmet. In the vege-
table-feeding Locustidtf, this part is sometimes
three-jointed, as observed by Newman* in
Acrydium, but usually it is simply an obtuse
double-jointed organ, hollowed on its inner
side; but in the Blattide it is expanded at its
extremity into a thick oval bulb, or soft
cushion, encircled with fine hairs, evidently
well adapted for touching or feeling. In all
the Orthoptera, but more particularly in the
Blattida, the articulation of the maxilla with
the sub-mentum is less compact than in the
Coleoptera ; and this appears to be referable to
the same circumstance as before noticed with
regard to the mobility of the anterior clypeus,
the voracious habits of the insect. Thus, to
allow of very extensive motion to the parts, the
stipes (2) is articulated at an angle with the
cardo (1), and a broad muscular structure, at-
tached along the inner border of the lacinia, as
far as the base of its sharp articulated apex,
upon which it acts, is interposed between the
maxilla and sub-mentum, and forms part of the
inferior boundary of the mouth. The mandibles
in this order of insects, as remarked by Marcel
de Serres,f are more perfectly constructed than
in any other. In those which masticate their
food, and devour large quantities of vegetable
matter, as the Locustid<e, the mandibles are
furnished both with cutting and grinding sur-
faces. The anterior or apical margin is deve-
loped into acute cutting teeth, somewhat like
the canine teeth of vertebrate, while the inner
and posterior part of the mandible is broad,
flattened, and covered with elevated irregular
ridges, like the teeth of some Herbivora, and is
admirably adapted for grinding or chewing.
This complicated structure does not exist in
the more carnivorous species, the Blattida, in
which the mandibles are arched, and indented
with sharp triangular teeth (fig. 373,f), very
closely resembling the cutting teeth of Carni-
vora, and are articulated by strong condyles at
the side of the head, on a line with the articula-
tion of the clypeus anterior, and not so far back
as that of the maxilla. The eyes in Orthoptera
are usually exceedingly prominent and round,
but not large, except in Blatta, in which they

* P. 32.

t Aouales des Museums, No. xvi. p, 56.

INSECTA.

897

are kidney-sliaped, and are spread over a great
part of the sides of the head. The ocelli,
which are found in most of this order, do not
exist in Blatta. They are very distinct 4n the
Gryttida and Locust'idtf, and also in the mole-
cricket; but it is remarkable, as Mr. Kirby for-
merly observed, that they are not met with in
the pupa or larva state of these insects. In the
pupa of the mole-cricket there are simply two
slightly elevated tubercles, in the situation in
which the ocelli are afterwards developed.
They thus appear to have reference to some
particular condition of the perfect insect, al-
though the habits of the three states appear to
be similar. The antenna are organs of much
importance, and are usually of considerable
length, except in the carnivorous Mantida, or
praying insects, in which they are very short.
These insects, which take their living food by
sight alone, have the shortness of thei* an-
tennae, the supposed organs of hearing, com-
pensated for by the immense size of their large
globular corneae, situated at the superior angles
of the head, so as to enable the insect to see in
every direction. But in those which reside in
the dark, or which seek their food by the aid of
other senses, the antennae are exceedingly long,
and formed of an immense number of joints,
especially in the Gryllida, Achetida, and
Blattida, which are noted for acuteness of
hearing. In the interior of the head the lamina
squamosa are thick and strong, and are articu-
lated, as in Hydrous, with the angles of the epi-
cranial suture superiorly, and inferiorly with the
temm* poster ioj-es, and the tentorium forms a
distinct ring, as in Lucanus.

In the Neuroptera we recognise the same
elementary parts in the head and mouth as in
the preceding Orders, but in this they are de-
veloped into new forms. The epicranium, so
conspicuous in the former, is reduced to its
minimum in this Order, owing to the immense
development of the organs of vision, which,
attaining their greatest extent in (Eshna gran-
dis, are expanded over the whole of the upper
and lateral surfaces of the head, and are ap-
proximated together in the median line, leaving
only the epicranial suture between them. A
small portion only of the epicranium exists
anterior to these great corneae, but in that por-
tion, as usual, are situated the ocelli; while
the minute antennae, reduced also to their mi-
nimum of size in these Libellulidte, the most
rapacious and insatiable of all insects, are still
situated, as in Coleoptera, at the external angles
of the suture. In the dilated anterior portion
of the head we distinctly recognize the clypeus
posterior and anterior, and below these the
transverse cordiform labrum, separated by su-
tures, but freely articulated together as in Or-
thoptera. At the lower concave margin of the
clypeus anterior in CEshna grandis is a short
triangular plate intervening between the clypeus
and labrum, and articulating with both like a
distinct segment; it is probably only part of
the labrum. On the under surface of the head
the guUi and sub-mentum are indistinct, and
merged as it were in the construction of three

VOL. n.

immensely dilated- doubly articulated plates,
which cover the whole lateral and under sur-
face of the mouth. The anterior portion of
the middle plate, which in (Eshna is rounded
at its anterior margin, is the true ligula, while
the articulation behind it, from which arise the
lateral plates, is the analogue of the mentum.
The two lateral plates, composed each of two
articulations, and in some species also of a
third very minute one in the form of a short
spine at the apex, we regard, with Brulle,* as
the proper labial palpi immensely dilated. The
mandibles concealed within the mouth are
short, strong, and, in Libellula quadrimaculata,
arched. At the apex they are bifid, and armed
with two sharp triangular teeth, and at their
base with four sharp-pointed ones, excavated,
and placed in different directions, adapted for
crushing and cutting rather than for mastica-
ting the food. Within the head they are arti-
culated with portions of the epicranial and ba-
silar regions, as in Coleoptera. The maxilla are
long and prehensile. The true palpi are en-
tirely absent, but the galea exists as an oblong
articulated lobe, and the lacinia, which is arti-
culated at its base and sharpened along its
inner margin, as in the Blattidte, is armed at
its apex with four crooked sharp-pointed teeth,
while the cardo is long, and articulated with
the base of the maxilla at an angle, to allow of
extensive motion, as in the maxilla of Orthop-
tera. In other families of the Neuroptera, as
in the Panorpida, the organs of manducation
are small, but the anterior part of the head is
elongated into a rostrum, occasioned by the
narrowing and extension of the clypei, as we
have before noticed in the Curculumtdtt, while
in the Pkryganida:, which take no food in their
perfect state, the parts of the mouth are almost
atrophied.

In Hymenoptera the mouth assumes an en-
tirely new form, but the changes in it are con-
fined to the maxillae and labrum, which are
soon to become its chief organs. The head,
placed vertically on the thorax, is still well de-
veloped. The epicranial region is large, and
extends very nearly to the insertion of the
antenna? on the front. In most species it is
densely covered with hairs, and the ocelli (Jig.
375, />,) which are constant in this class, are
usually arranged in a triangle on its most ver-
tical part. The cornea (c) are large and kid-
ney-shaped, and cover part of the lateral sur-
face of the head, leaving between them a broad
front, occupied by the clypei (d) and part of
the epicranium. But in the males of the hive-
bee, which come abroad only in the brightest
sun-light in quest of the female, this space is
diminished, and the corneae are expanded over
part of the front, and the whole of the epicra-
nial region, as in the Libellula; the most ex-
tensive vision being required by these insects,
to enable them to discover the object of their
solicitude, as by the other in the pursuit of its
prey. In some of the pollenivorous and pre-

* Annal. Soc. Entom. de France, torn. ii. p.

3 N

INSECTA.

Fig. 375.

Anterior and inferior views of the mouth and head of

Anthophora retusa.

A, antenna ; b, epicranium and ocelli ; c, cor-
nea ; d, clypeus anterior ; e, labruin ; f, mandi-
ble ; g, the maxilla; h, its palpus; i, feeler-
bearer or part of the ligula ; h, labial palpus ; /,
mentum ; m, sub-mentum ; 1, cardo of the maxilla ;
2, stipes ; 5, the lacinia or blade ; *, ligula; **,pa-
raglossce, its lateral lobes.

daceous genera, the Tenthredinida and Ves-
pidtE, the clypeus posterior seems to have be-
come entirely obliterated, unless we regard the
broad clypeus in these insects, as in the Hornet,
the posterior one, and the plate concealed be-
neath it, within the mouth, to which the
labrum is attached, as the anterior. But we
are not inclined to do this, because in some of
the Ichneumonid<£ and Sphecidte a trace of the
clypeus posterior remains a little anterior to the
antennae. In Ichneumon Atropos the clypeus
is narrowed and depressed in its middle, as if
originally formed of two parts, while in Ammo-
phila vulgaris the clypeus posterior is clearly
indicated as a minute triangular plate situated
in the middle line, immediately beneath the
insertion of the antennae, and it exists in a
similar form in some of the Apida, as in the
large female Bombus lapidarius, and in some
specimens of Anthophora, the clypeus posterior
being in all instances bounded by a trace of the
triangular suture. The labrum (c) is always
distinct, but variously formed. In Vespidte it
is narrow, acute, and hidden beneath the ante-
rior clypeus; in the leaf-cutting bees, Mega-
chile, it is narrow and quadrate; but in the
hive and humble-bees it is large, and rounded
at its anterior margin. The mandibles are sub-
ject to considerable variation of form.* In

* See Essay on Fossorial Hymenoptera, by W. E.
Shuckard, p. 12, et seq.

some, as in Ammophila, which burrows in the
sand, they are long, hooked, and furnished
with but a single tooth at the apex, without
cutting edges ; and they are of somewhat the
same form in Anthophora (fig. 375, f), whose
habits of life in this respect are similar. In the
Vespidte, which gather the materials for their
nests by rasping off little packets of fibres from
decaying wood, they are broad, triangular, and
armed along their edges with strong teeth ; and
such is also their structure in Anthidium mani-
catum, which scrapes off the down from the
woolly stems and leaves of plants for the same
purpose; while, in the hive-bee, which em-
ploys them in moulding the soft wax in the
construction of the combs, they are shaped at
the apex like a spoon, without indentations ;
their form in each instance being thus dis-
tinctly referable to the habits of the insects.
In the gregarious species there is also a dif-
ference in their form in the two sexes, those of
the males being often smaller and less curved
than of the females, or workers, and they are
always, particularly in the Bombi, more densely
covered with hairs.

In the whole of theTerebrantia, Pupophaga,
and some of the Aculeata the mandibles are
still the chief cibarian organs ; the Athalia em-
ploys them in masticating the pollen of flowers,
and the maxillae and labium in sipping the
honey; while the omnivorous Formicidte and
Vespida employ them in tearing and masti-
cating their food, whether it be the pulpy sub-
stance of fruits, or the muscles and hard cover-
ings of other insects. In the Apida the chief
use of the mandibles is in constructing the
nest, while the maxillae and labium are the
only organs employed in taking food. In the
strictly carnivorous families the maxilla are not
longer than in the preceding Orders. In most
of these, as well also as in the Terebrantia and
Chrysidida:, the extremity of each maxilla is
obtuse, and divided into a distinct lacinia and
galea, and the palpi are long and six-jointed.
In the FormicidtE and Vespidee, which subsist
upon fluid as well as solid aliment, their length
is increased ; but in the true Apidte, which
subsist entirely upon honey, they are drawn
out to a great length, and, with the labium be-
neath, form a tube through which the aliment
is conveyed to the mouth, as in the hive and
humble-bees. In these species the cardo (1)
is long, slender, and formed of two parts, which
conjointly articulate with the stipes (2). The
longest of these, the basilar portion, has two
apophyses at its extremity, and is articulated
with the anterior part of the base of the cra-
nium, at the inner side of the articulation for
the mandibles, exactly as in Coleoptera; and
its muscles in like manner are attached to the
lateral and inferior parts of the head and orbital
plates. It is the lora, or lever of Kirby, which
enables the insect, by the additional articula-
tion of its second part with the sub-mentum, to
thrust out the maxillae and labrum together to a
great distance. The part that articulates with
the sub-mentum, the proper cardo of Kirby, is
very short in Bombus lapidarius, but of consi-

INSECTA.

899

Fig. 376.

Lateral view of the mouth of Anthophora. Letters
and figures as before. 12, the lingua, or tongue.

derable length in Anthophora. In each in-
stance it is broadest at its articulation with
the stipes, and, passing backwards diagonally,
unites at its extremity with a corresponding
part of the opposite side, and the two thus
joined articulate with the narrow sub-mentum,
the fulcrum of Kirby. The stipes forms the
lateral basilar part of the maxilla, and is shorter
in Anthophora than in Bombus, in which it is
about one-third of the length of the maxilla.
The pfilpijer is also distinct (3). The lacinia (5)
is of great length, and gradually tapers to its
extremity. Internally it is slightly concave,
and externally is covered with a few scattered
hairs. It is articulated freely with the stipes
and palpifer, upon which it is inflected in a
state of rest to form a sheath for the labium,
when the parts of the mouth are folded. When
the maxillae are extended to form the sucking
tube with the labium, they are a little separated
at their base, and inclose between them the
cavity of the mouth, within which is a soft
fleshy body, the lingua (12) or true tongue,
situated anterior to and serving as a valve to the
pharynx. The sub-mentum (m) is articulated
by a single joint with the united extremities of
the two cardines (13). It is long and narrow
in Anthophora, but short and triangular in
Bombus. It is attached at its sides by a fine
membrane to the under surface of the head and
throat. The mentum (/) articulates with the
sub-mentum, and is an elongated rounded plate,
which forms internally a channelled passage
to the pharynx. Within it are inserted the
muscles of the labial palpi (/c). These organs
are long and styliform, and arise from a space
at the base of the ligula, the part described as
the palpiger by Newman. Their great length
is occasioned by an excessive elongation of the
second basial joint, which is sometimes as long
as the whole maxilla itself, and is furnished at
its distal extremity with a minute brush of
hairs, and also articulates with the remaining

short joint of the organ. The .remaining por-
tion of the labium is divided into three parts.
The two lateral ones are short styliform pro-
cesses, the paraglosstf (**), and the central one,
commonly called the tongue of the bee, is the
part employed by the insect in gathering honey.
In Apis, Bombus, and Anthophora it is a long
tapering muscular organ, formed of an immense
number of short annular divisions, and densely
covered throughout its whole length with long
erectile hairs. It is not tubular but solid, and
when actively employed is extended to a great
distance beyond the other parts of the mouth,
but when at rest is closely packed up and con-
cealed between the maxillae. The manner in
which the honey is obtained when the organ is
plunged into it at the bottom of a flower, is by
lapping, or a constant succession of short and
quick extensions and contractions of the organ,
which occasion the fluid to be accumulated
upon it, and ascend along its upper surface,
until it reaches the orifice of the tube formed
by the approximation of the maxillae above,
and the labial palpi and this part of the ligula
below. At each contraction a part of the ex-
tended ligula is drawn within the orifice of the
tube, and the honey with which it is covered
ascends into the cavity of the mouth, assisted
in its removal from the surface of the ligula by
the little brush of hairs with which the elon-
gated second joint of each labial palpus is fur-
nished. From the mouth the honey is passed
on through the pharynx into the oesophagus by
the simple act of deglutition, as in other ani-
mals. In Anthidium the ligula is not longer
than the labial palpi; while in the Andrenida
all the parts of the mouth are much shortened,
and resemble similar parts in the Vespida in
being divided into four lobes.* In the latter
insects the ligula is quadrifid, and is dilated
at its apex, and each lobe is terminated by a
minute gland.f The two lateral lobes, para-
glosstf, are shorter than the middle ones. In
Tenthredinidte the ligula is also short, but is
divided only into three lobes.

We have thus seen that the head and its ap-
pendages are most perfectly developed as a
whole in the Coleoptera, and that in passing
through the succeeding Orders of Mandibulata
certain parts are more or less developed in each
Order, in accordance with the general habits
and mode of life of the insects ; that in the
carnivorous and omnivorous families, and in
those whose habits of life require a great
amount of strength, either in procuring their
food or in the construction of their nests, the
mandibles are the most important of the oral
organs, and are most largely developed. But
as we pass from insects with these habits to the
Haustellata, whose food and modes of life are
of an entirely different description, the man-
dibles lose their importance, and become atro-
phied, and their office, now altered in its cha-
racter, is performed by the maxillae and labium,

22.

* Newman. Paper on the Head of Insects, p.
t Curtis. Westwood.

3 N 2

900

INSECTA.

the development of which, in the higher forms
of insects, is only of secondary importance, com-
pared with that of the mandibles, but is now
carried to so great an extent that these organs
become almost or entirely the sole means of
taking food. Not only do these changes take
place in the parts of the mouth, but the whole
head undergoes a similar alteration in the rela-
tive form and size of its parts, occasioned by
the excessive development of the organs of vi-
sion. Thus in the Lepidoptera, (Jig. 377,) the

Fig. 377.

The head and parts of the mouth of Sphinx ligustri.
A , antenna j fe, epicranium ', c, cornea ; d, cly-
peus posterior ; e, labrum ; f, mandible ; g, max-
illa or proboscis ; h, maxillary palpus ; B, base of
the maxilla with the mandibles and labrum; C,
lateral view of the same.

lateral and a large portion of the inferior surface
of the head is entirely occupied by the corneae
(c), which are also extended far forwards upon
the anterior. The occipital region is confined
to the flat surface that is approximated to the
prothorax. The epicranium (6) is distinct, and,
as in the preceding Orders, extends as far an-
teriorly on each side as the base of the antennae
between the cornese, but the suture that sepa-
rates it from the clypeus posterior (d) is almost
transverse. The clypeus posterior is very large,
and occupies the whole of the space between the
cornese, on the front of the head. It is convex
as in Neuroptera, and is narrowest at its inferior
part. The clypeus anterior appears to exist in
the form of a minute transverse plate, a little
elongated in its middle on the hinder part, and
separated by a transverse groove on its anterior
from a much smaller plate, the labrum (e), with
which it is consolidated. This part, which was
first detected in Lepidoptera by the accurate
Savigpy,* is also a small convex transverse
plate with a little triangular scale at its anterior
margin, fitted closely to the front of the max-
illae. In Sphinx ligustri, (fig. 377,) the separa-

* Memoires sur les Animaux sans Vertebres.

tion of the labrum by suture from the part which
we regard as the clypeus anterior, is distinct,
but it appears to have been overlooked by Sa-
vigny and others. On each side of the labrum
are the rudiments of the mandibles (/). They
are two minute, iriangular plates, attached in
part to the labrum and margin of the clypeus,
to which, as Savigny has remarked, they
appear to be soldered. They are applied to
the base of the maxillae, and in Sphinx appear
each to be formed of two parts, and are co-
vered along their inner margin with stiff hairs.
They are the remains of the large corneous
mandibles of the larva. We are indebted for
their discovery to the indefatigable researches
of Savigny, who first traced their identity. The
labium, which forms so conspicuous a part of
the mouth in the preceding Orders, like the
mandibles, is reduced to insignificance in this.
It is a small triangular plate, closely attached
to the under surface of the head, at the base of
the maxillae, and its division into parts, so dis-
tinct in other insects, is now scarcely perceptible.
The labial palpi (/c) arise one on each side of
the labium. They are usually long, hairy, and
three-jointed, and are reflected on the front of
the head. Next to the maxillae they are the most
conspicuous parts of the mouth, particularly
in Pyralidtf and Tortricida, in which they are
long and pointed. The lingua has been sup-
posed to be entirely absent in Lepidoptera. It
was not detected by Savigny. Latreille be-
lieved it to exist in the suture at the floor of
the mouth, but Mr. Newman has observed a
small mammiform protuberance in Sphinx li-
gustri which he regards as the analogue of the
tongue in this Order. The labrum, mandibles,
and labium are entirely concealed by the re-
flected labial palpi and a dense clothing of
scales, and are only observed when the anterior
part of the head is completely denuded of
these coverings. Their atrophied condition
affords a beautiful illustration of the law that
in proportion as the functions of an organ be-
come suspended, or are rendered unnecessary
by the employment of other parts, the organ
itself becomes wasted and utterly useless, and
perhaps entirely disappears. Thus in those
Lepidoptera whose food is liquid honey pro-
duced in the deep chalices of flowers, the
short mandibles of the voracious herbivorous
larva would be entirely useless to the perfect
insect, and its food would be inaccessible
to it. Accordingly we find that the man-
dibles are now unimportant organs, and
the office of conveying food to the mouth is
performed solely by the maxillae (</), which
are extended in the shape of a long sucking
tube. Each maxilla is composed of an im-
mense number of short, transverse, muscular
rings. It is convex on its outer surface, but
concave on its inner, and the tube is formed by
the approximation of the two organs. When
at rest they are rolled up like a watch-spring,
between the large labial palpi, but are capable
of being darted forth in an instant. They are
the so-called tongue, or proboscis of the but-
terfly and moth. Each maxilla has usually

INSECTA.

901

been described as being hollow in its interior,
or forming " in itself a tube,"* which appears
to have arisen from the circumstance of there
existing in each, one or more large tracheal
vessels, (Jig. 378, 6, e,) connected with the
tracheae of the head, and which are divided, as
they approach the extremity of the organ, into a
great number of minute ramifications, but which
have no communication with the external sur-
face, their distribution being precisely similar to
that of the trachese in other parts of the body.
The maxilla is composed of elementary parts,
as in the preceding Orders, but they are not
easily distinguished. The long extensile por-
tion is the proper lacinia, which is constricted
at its base, immediately beyond which is situ-
ated, in Sphinx ligustri, a minute three-jointed
hairy palpus (h). Mr. Newman could not de-
tect this maxillary palpus in Sphinx,f and hence
concluded that it was obsolete in this family.
It is indeed exceedingly minute and easily
overlooked, but is distinctly three-jointed, and
densely covered with long hairs. The structure
of the maxillae in different genera and species
is particularly interesting, and their length is
exceedingly various. Thus in the Sp/ungid*,
in Smerinthus ocellatus, which takes no food,
they scarcely exceed one-eighth of an inch,
while in Sphinx ligustri, which continues ho-
vering on the wing while extracting the sweets
from a flower, they are nearly two inches in
length, and this is also the case in the hum-
ming-bird moth, Macroglossa stellatarum.
In the butterflies, and in many of the Noc-
titidz, they are often about equal to the length
of the body. The inner or concave surface
which forms the tube is lined with a very
smooth membrane, and extends along the an-
terior margin throughout the whole length of
the organ, as in the transverse section, (fig.
378, 6, 6.) At its commencement at the apex
it occupies nearly the whole _ breadth of the
organ, and is rather smaller than at its termi-
nation near the mouth, where the concavity or
groove does not occupy more than about one-
third of the breadth. In some species the ex-
tremity of each maxilla is furnished along its
anterior and lateral margin with a great number
of minute papillae, but in others these parts are
entirely absent. They are extensively deve-
loped in some of the butterflies, as in Vanessa
atalanta, (fg. 378, 1, 2, c,) in which they
are little elongated barrel-shaped bodies, (4, c,)
terminated by three smaller papillae, arranged
around their anterior extremity, with a fourth
one a little larger than the others placed in
their centre. These papillae are arranged in
two rows along the lateral and anterior surface
of each maxilla, near its extremity, for about
one-sixth part of its whole length, as at 1, and
5, c, d. There are seventy-four in each max-
illa, or half of the proboscis. To judge from
their structure, and from the circumstance that
they are always plunged deeply into any fluid
when the insect is taking food, they may pro-

Fig. 378.

Parts of the maxillae or proboscis of Vanessa atalanta.

\, external surface of the apex with the double
row of papillae ; 2, internal or concave surface ; a,
transverse muscles; 6, tube; c, papillae; d, hooks
which join the maxillae; 3, one of the hooks ; 4,
one of the papillae ; 5, section of the tip of the
maxillae, showing the position of the papillae on each
side of the tube ; 6, section of maxillae near their
base, showing the position of the tube, 6; the large
trachea, e, and the smaller one and nerve, /.

bably be regarded as organs of taste. They are
largely developed in this genus of insects, but
in Pontia, the common white butterflies, and
in Sphinx ligustri they are scarcely perceptible.
There are also some curious appendages ar-
ranged along the inner anterior margin of each
maxilla, in the shape of minute hooks, which,
when the proboscis is extended, serve to unite
the two halves together. They were first no-
ticed by Reaumur,* and subsequently by Mr.
Kirby.t In many insects, as in Sphinx and
Pontia, they have more the appearance of
cilia, like the barbs of a feather, than of hooks,
but in Vanessa they are falcated, and furnished
with an additional tooth (3, d} a little beyond the
apex. They are so exceedingly minute, and ar-
ranged so closely together, that their true form
is with difficulty distinguished. They lock
across each other like the teeth in the jaws of
some fishes, and we are inclined to believe that
the points of the hooks in one-half of the pro-
boscis are inserted, when the organ is extended,
into little depressions between the teeth of the
opposite side, so that they form the anterior
surface of the canal, but of this we are not con-

* Newman on the Head of Insects, p. 28.
t Op. cit. p. 28.

Memoires, &c. torn. i. p. 125.
Introduction, vol. i. p. 394.

903

INSECTA.

fident. That they really form the anterior sur-
face of the canal or tube seems evident from
the distinctness with which coloured substances
are observed to pass along the tube when the
insect is taking food.

There are various opinions with regard to the
manner in which the food ascends the tube to
the mouth. Some have imagined that it is
simply by capillary attraction, and others, the
chief of whom was Lamarck, that it is forced
along by successive undulations and contrac-
tions of the sides of the tube, occasioned by
the action of the transverse muscles. Kirby
and Spence* believe that these undulatory
motions, which certainly do exist to a consider-
able extent, are not sufficiently powerful to
carry along the food with the rapidity with
which it usually ascends, but that the lateral
canals, which, as we have just shewn, are the
proper tracheae of the organs, assist in pro-
ducing the phenomenon by occasioning a
vacuum in the mouth and tube which faci-
litates the conveyance of the food more rapidly
along it. That something of this kind does in
reality occur is proved by the following ob-
servation. We gave sugared water, coloured
with indigo, to two specimens of Pontia napi,
and on attentively examining the front of the
organ with a microscope while the insects were
busily employed in partaking of the fluid, ob-
served the particles of indigo disseminated in
it ascend along the tube, not in a gradual and
regular succession, as must have been the case
had the ascent of the fluid been occasioned
simply by capillary attraction, but pumped up,
as it were, sometimes in a full stream in quick
succession for one or two seconds, as if the
insect was then sipping a full draught, while
at others a few particles only ascended quickly,
followed by still fewer with a much slower
motion ; thus indicating distinct intervals be-
tween each draught or ascent of fluid. From
these circumstances we are led to offer the
following explanation of the manner in which
the food ascends the tube to the mouth. The
instant an insect alights upon a flower, it makes
a forcible expiratory effort, by which the air is
removed both from the tracheae that extend
through the proboscis, and from those with
which they are connected in the head and
body, some of which we shall hereafter see
are distributed over the oesophagus and ali-
mentary canal, and at the moment of applying
its proboscis to the food makes an inspiratory
effort, by which the tube is dilated, and the
food ascends it at the instant to supply the
vacuum produced, and is earned onward by
the same act to the mouth, and from thence
by the action of the muscles of the pharynx
into the oesophagus and stomach, without any
interruption of the function of respiration, the
constant ascent of the fluid into the mouth
being assisted by the action of the muscles of
the proboscis, which continue in action during
the whole time the insect is feeding. By this
combined agency of the acts of respiration and

* Introduction, vol. iv. p. 470.

the muscles of the proboscis, we are enabled to
understand the manner in which the humming-
bird sphinx extracts in an instant the honey
from a flower while hovering over it without
alighting, and which it certainly would be
unable to do so rapidly were the ascent of the
fluid dependent only upon the action of the
muscles of the organ.

In Diptera there is the same irregularity in
the development of certain parts of the head as
in Neuroptera and Hymenoptera. The shape
of the head is usually that of a flattened hemi-
sphere, with its base or occipital region con-
cave, and approximated to the prothorax, as in
the common house-flies, Muscidtf, the blood-
suckers, Tabanida, and the gad-flies, (Estruhe.
But in others, as in the gnats, Culicida,
the long-legs, Tipulida, and the As&d*,
(fig. 349,) it is either convex at its occipital sui-
face or extended in the form of a short neck.
In the latter instances the occipital and epi-
cranial regions are large and distinct, and the
cornea are protuberant, and situated a little
anteriorly at the sides of the head, but do not
much encroach upon the epicranium. This is
not the case in the Tabanida, &c. in which they
occupy nearly the whole of the epicranial
region. But in most of the genera in which the
eyes are thus expanded, there is usually, as in
Neuroptera, some portion of the epicranial region
still existing in the form of a small triangular
space anterior to the inner margin of the corneae.
On this space the longitudinal portion of the
triangular suture is often distinctly marked, and
extends backwards between the corneas to the
occiput, as is well seen in Tabanus hovimts.
Anteriorly it extends as far as the middle line
behind the antennae, where it terminates, thus
distinctly indicating the proper boundary of the
clypeus posterior in this order. The whole
front of the head or face is formed of the two
clypei, which are so united together as to be
scarcely distinguished as originally separate
parts. They together form a broad and some-
what lozenge-shaped plate, at the upper
portion of which are situated the antennae,
and at the lower or anterior, which is notched,
the labrum, freely articulated with it, and
which is usually concealed beneath it. In
some genera, as in the Tabanida, the an-
tennae are inserted on each side of the middle
line, into little fossae close to the triangular
suture; while in others, as in Chrysotoxum and
Conops, the place of these fossae is occupied by
little elevations, upon which those organs are
seated, sometimes nearly close together, as in
Sargus. The face thus formed of the two
clypei is developed laterally on each side of
the corneae, and is gradually narrowed from
its upper part to its lower, where it is articulated
with the labrum. In Rhingia rostrata the
posterior clypeus is elongated, and forms the
long projecting front : it is deeply notched at
its interior margin, where, as also in Volucella,
is a very minute plate, apparently the ana-
logue of the clypeus anterior. The cornea,
as above stated, are usually the most conspi-
cuous parts of the head in Diptera, and form

INSECTA.

its lateral regions. They are always largest, as
in Neuroptera, in those species which are most
constantly abroad in the brightest light, and
are expanded over nearly the whole of the
epicranial region, as in Tabanus, Ckrysotoxum,
and Doros. But although the corneae of the
compound eyes are so largely developed, ihe
ocelli also are almost invariably present in this
order. They are generally three in number,
placed on the most vertical part of the epi-
cranium, immediately behind the proper corneae.
This is their situation in Musca, Helophilus, and
Stratiomys,and also in the gnat, Culex annulatus,
but we have not observed them in a neigh-
bouring genus, Pedicia. Professor Muller*
believes that the ocelli are designed chiefly for
observing near objects, and the fact of their
existing, as just stated, in many insects in
which the corneae of the proper eyes are ex-
ceedingly large, seems to favour this opinion.
Their presence, as in Hymenoptera, is most re-
markable in the males, as in the male Empidte,
in which, although the proper cornese cover
the whole surface of the head, yet there are
also three large ocelli situated in the trian-
gular space immediately behind the cornese,
and even elevated upon a pedicle. In Tabanus
there appears at first to be only a single ocellus,
situated in the median line between the corneae
at the anterior part of the head ; but on close
inspection it is found to be divided into two by
the longitudinal suture which passes through it,
so that the two ocelli from their close approxi-
mation appear but as one.

In the organization of the mouth the same
parts exist in Diptera as in the preceding
orders, but modified in form to adapt them to
a different mode of use. Thus we have seen
that in Hymenoptera and Lepidoptera it was
simply necessary that the parts should be
elongated, to enable the insects to obtain the
liquid food already prepared for them ; but in
Diptera not merely was it necessary that this
should be the case, but also that their form
should be materially altered, to adapt them to
a mode of employment different from that of
analogous parts in other insects. Thus in
Tabanidtf, the labrum and mandibles are used
like lancets, to pierce the integuments of other
animals, before these parasitic blood-suckers
can obtain the living fluid they are in quest of;
while in other species, as in Eristalis jloreus,
(fg~ 379,) which subsists both on the pollen
and honey of flowers, the mandibles and
maxillae are employed to scrape off the pollen
from the anthers, before it is conveyed along
the tube formed by the united parts of the
mouth to the pharynx. In other Diptera, of
which the food is entirely fluid and easily ac-
cessible, as in the common house-flies, Muscidte,
all the parts of the mouth are soft and fleshy,
and simply adapted to form a sucking tube,
which in a state of rest is closely folded up in
a deep fissure, on the under surface of the
head, formed by the two sides of the clypeus.

* Elements of Physiology, by J. Muller, M.D.,
(translated by W. Baly, M.D.,part v. p. 1116.

903

Fig. 379.

Mouth or proboscis of Eristalis jloreus.

d, front beneath the clypeus ; e, labrum ; /, man-
dible ; g, maxilla and palpus ; i, labium ; i*, labium
dilated ; **i, inner surface of paraglossa ; ***», the
rows of hairs on the inner surface ; I, ligula j mf
cardo and submentum.

On the other hand, in the (Estrida, which, as
we have seen in the Phryganidte, Bombycida,
and others that take no food in their perfect
state, all the parts of the mouth have entirely
disappeared. It is in Tabanidte that the oral or-
gans of Diptera are most perfectly developed,
and approach nearest to those of Hymenoptera,
and are easily distinguished ; while in the soft
fleshy proboscis of Muscida their identification
is a matter of considerable difficulty. Ac-
cording to Savigny* the proboscis of Diptera
is formed solely by the labium, or under-lip,
divided into its primary parts as in other in-
sects ; while Desvoidsyf on the contrary be-
lieves that it is not formed by the labium, but,
as in Lepidoptera, solely by the maxillae. Now
we have seen, that although in Lepidoptera
the maxillae alone form the tubular mouth or
proboscis, yet that in Hymenoptera the labium
is the part chiefly employed in gathering the
honey, which is conveyed to the cavity of the
mouth and pharynx only by the maxillae as-
sisting to form a tube of which the labium
constitutes the inferior portion. Analogy there-
fore would lead us to expect a somewhat si-
milar conformation of the mouth in Diptera,
and that since these insects have either to pierce
the coverings of other animals before they can
obtain their food, or to gather their nourish-
ment by employing the proboscis as a pre-
hensile organ, the maxillae may fairly be sup-
posed to enter into its formation, and accord-
ingly we find, on a careful examination, that
such is actually the case, and that the proboscis
is formed of the maxillae and labium united.
We have been led to this conclusion by a care-

* Mem. sur les Anim. sans vertebres.

t Essai sur les Myodaires, par le Docteur J. B,.
Robineau Desvoidsy, 4to, 1030, torn. x. Me-
moires de 1'Institut de France.

904

INSECTA.

ful examination and comparison of the parts of
the mouth in Volucella,Echinomyia,3ind Musca,
with those in Tabanida and Asilidte. To com-
mence our observations with the most perfect
form of mouth, we find in Tabanidte that the
tub rum is an elongated, acute, corneous plate,
freely articulated to the margin of the clypeus,
and marked along its middle line with a
raphe. It is concave on its under surface, and
is as long as the mandibles and maxillae, which
it partially covers, and somewhat resembles in
appearance. In Culex it is longer than these
parts, and is more sharp-pointed. In Asilus
crabroniformis it is much shorter than either
the mandibles or maxillae. It is narrow, tri-
angular, and rounded at its apex, with a slight
indentation, and is not used by the insect as a
lancet, as in the preceding instances, but merely
forms the anterior covering of the mouth. In
Eristalis Jloreus (e) it is a short mitre-shaped
plate, which covers the base of the mandibles
and maxillae, and articulates freely with the
clypeus. In Volucella bombylans it is reduced
to a very narrow short plate, articulated with,
and, in a state of rest, inflected beneath a small
triangular one, which is inserted into a deep
cleft of the clypeus, and which appears to be
the proper analogue of the clypeus anterior.
In Rhingia rostratait has almost entirely dis-
appeared, so likewise has the part that we
are inclined to regard as the clypeus anterior,
which is inserted into the cleft at the extremity
of the elongated rostriform anterior part of the
head. In EcMnomyia it still exists as a very
narrow corneous plate articulated with the
clypeus, inflected beneath the head when the
proboscis is retracted, but forming the anterior

fortion of its base when the organ is extended,
n Musca it has entirely disappeared as a dis-
tinct piece, but seems to have become the
union of two corneous plates, which together
form an arch on the front of the mouth, or base
of the proboscis, and represent the mandibles,
the intervening space being covered by a strong
membrane. The mandibles, which had almost
disappeared in Lepidoptera, still exist in the
rapacious Diptera, and in those which pierce
the skin of other animals. In Tabanus they
are long, and somewhat lancet-shaped plates,
situated immediately beneath the labrum.
They are slightly curved, like a cutlass, and
sharp-pointed. They are not employed in
crushing or cutting solid food, as in proper
mandibulated insects, but in puncturing or
piercing with a horizontal motion from be-
hind forwards, and not from side to side.
In this genus, however, their motion appears
to be not simply that of thrusting or pier-
cing, but also that of cutting vertically with
a sweeping stroke, like the lancets of a cup-
ping instrument, for which motion they are
well adapted by their cotyloid form of arti-
culation. In the common gnat, Culex, they
are very slender, and sharp-pointed. The pain
occasioned by the piercing, or supposed biting
of the insect, arises from the act of thrusting
these instruments through the skin. In these
instances the mandibles are equal in length to

the other parts of the mouth, but in Eristalis,
in which they have still the same acute form,
they are somewhat shorter. In the rapacious
Asilus crabroniformis the mandibles of the two
sides are united to form a single, strong, sharp-
pointed barb, very acute, and ciliated at the
apex on its upper surface, and projecting be-
yond the other parts of the mouth. In Rhingia
rostrata they still exist as delicate elongated
setae, approximated at their apex ; but in the
neighbouring genus, Volucella, we have been
unable to detect them, except as two flat plates,
approximated to the anterior part of what we
regard the proper cardines of the maxillae and
labrum, and by which the parts of the mouth
are thrust forwards. In Eckinomyia the man-
dibles have also disappeared as distinct organs,
and seem to be united to the base of the car-
dines within the mouth, as in Volucella, and
there is a similar condition of these parts in
Musca, in each instance the anterior part of the
mouth being covered by a strong membrane,
which supplies the place of the horny labrum.
The lingua exists in most Diptera. It is
largely developed in Tabanus, in which it is a
single horny seta situated between the man-
dibles in the centre of the mouth. It was dis-
tinctly pointed out by Savigny, and subse-
quently by Latreille. It was called by the
former the hypopharynx. The maxilla, like the
mandibles, undergo a gradual diminution of
size. In Tabanus they are straight, and as long
as the mandibles, but narrower and less acute.
In Asilus, (jig. 380, g) they are very acute and

Fig. 380.

Under surface of the mouth of Asilus crabroniformis.

m, siib'nentum ; 1, cardo ; 2, stipes j 3, palpifer ;
5, lacinia ; h, maxillary palpus ; I, mentuin j
i, ligula.

INSECTA.

905

strong, with sharp cutting edges. They are short-
er and narrower than the mandibles, and are
usually inclosed within the sheath or proboscis
formed by the labium. In this family some of
their primary parts are easily distinguished.
Thus the blades (5) that lie within the sheath
of the labium, are the true laciniae in other
insects. These are articulated at their base
with the palpifer (3), a small triangular plate,
which bears the maxillary palpus and is situ-
ated most externally, — and also with a broad
squamous plate (2), which is united at its base
to its fellow of the opposite side, and appears
to be analogous to the stipes and cardo(l)
united. This plate, with its fellow, forms the
anterior boundary of the throat, and is closely
united to the proper gula that bounds the
anterior margin of the occipital foramen. The
muscles attached to the posterior margin of the
mentum and submentum pass over this plate
to be attached, one set to the anterior margin of
the gula, and the other to the posterior. In
Volucella bombylans the maxillae have lost
much of their importance, but are still easily
distinguished, and, with the other parts of the
mouth, are beginning to be merged in the
united fleshy proboscis. The cardines, upon
which all the motions of flexion and extension
in this kind of mouth depend, are very largely
developed. They are two elongated plates,
approximated to each other along their inner
margins, and to two triangular plates, the re-
mains of the mandibles, at their anterior and
lateral. The cardines thus form the posterior,
or basilar part of the proboscis, and the plates
which, from being articulated within the
margin of the clypeus posterior, we regard as
analogous to the mandibles, the lateral. At
their inferior portion, which forms the joint or
elbow of the proboscis, the cardines are freely
articulated with the stipes, which is a short
plate not easily distinguished from a part of the
mandible with which it is also in apposition.
Between the stipes and cardo is a short trian-
gular plate, the palpiger, rounded at its most
inferior part, and, with its fellow of the oppo-
site side, assisting to form the elbow or joint of
the proboscis. The maxillary palpus, which
aises from its external border, is long and
slender, and appears to be formed of three
short joints and one very long one. At the
inner and anterior margin of the palpifer and
stipes is articulated the lacinia, which, as in
Asilus, is of considerable length. It is inte-
resting to remark, that in this insect, which is
parasitic in its habits, insinuating itself into
the nests of humble-bees to deposit its eggs,
the mandibles, as just shewn, are atrophied, and
the two laciniae of the maxillae, although dis-
tinct from each other, are approximated in the
middle line to form the anterior or upper sur-
face of the tube to the mouth, as in Hymen-
optera, the sides and lower portion of the tube
being formed by the labium, and all the motions
of extension and flexion in the proboscis being
dependent upon the cardines, as we have before
seen in Hymenoptera. In this genus there-
fore we discover one of the transitionary forms

of mouth from that of the blood-sucking in-
sects to those of the more omnivorous feeders,
all the parts of the mouth being less and less
distinct in proportion as the act of taking food
is less complicated. Thus we have seen that
in Tabanus distinct mandibles are required to
pierce the skin of an animal, before the food is
accessible; but in the Muscida, whose fluid
aliment is every where present, a complicated
form of mouth is unnecessary, and accordingly
we find it reduced to a simple sucking tube.
In Eristalis the maxilla are present, as in
Asilus and Volucella, as also are their palpi,
which are nearly equal to them in length. In
Eckmomyia they are less distinct than inVolu-
cella. The anterior part of the proboscis at its
base is formed simply by a broad membrane
united to the anterior margin of the atrophied
mandibles, while the laciniae, which were dis-
tinct in the preceding genera, are united in
this genus to form the front of a lower portion
of the organ. That this union has taken
place is shewn in the presence of the maxillary
plpi, which invariably exist in Dipterous
insects. In all the Muscida the palpi arise
from a distinct palpifer, which appears to be
connected with a proper stipes, but the re-
maining parts are not easily distinguished.
It seems evident, however, that at least the
basilar portion of the proboscis is formed by
the union of the laciniae above and the labium
below, as in Hymenoptera, and that the la-
bium forms the chief portion of the organ,
contrary to the opinion of Desvoidsy, who
believed that the proboscis of Diptera was
formed of the maxillae alone, and to that of
Savigny, who regarded the proboscis as formed
only of the labium. The principle therefore
upon which the proboscis of Diptera is con-
structed, is precisely analogous to that of
Hymeuoptera, but there are important diffe-
rences in the form of similar parts in the two
orders. The labium includes the same primary
parts as in Hymenoptera, but the labial palpi
are almost invariably absent. The submentum
is usually indistinct. In Asilus the part we
regard as such is a small triangular plate, (m,)
distinguished only when the parts are examined
by transmitted light. It is situated between
the anterior portions of the two cardines. In
Volucella it is that part of the proboscis which
is nearest to the cardines, close to the articu-
lation. In Culex, in which the cardines are
short, it is situated very close to the under
surface of the head ; in other Diptera it is fre-
quently very indistinct. The mentum on the
contrary is always a conspicuous part. In
Asilus it is the broadest part of the proboscis (/).
It is a strong horny plate, deeply channelled on
its upper surface to form a canal to the mouth,
and receive within it the mandibles and max-
illae. It is articulated with the ligula, or ex-
tremity of the proboscis (*), which is distinctly
formed of two halves approximated together,
and naiTowest at the apex, with three slight
lateral dilatations. In Volucella the mentum
in like manner is a strong deeply channelled
plate, covered above by the laciniae. There is

906

INSECTA.

a similar structure of the proboscis in Eristalis.
The submentum is the part in which the flexion
of the organ takes place ; the mentum, as in
the preceding instances, is a strong horny plate,
almost closed on its upper as well as its under
surface, and the ligula is horny, but terminated
by soft dilatable lips. The ligula is always
articulated by a distinct joint with the mentum,
and appears to be constantly present in this
order. In Asilus, as we have just remarked,
it is strong and corneous, but in the less rapa-
cious insects, as in Eristalis, and the Muscidte,
it is terminated by two dilated fleshy lips,
which we regard as the analogues of the
paragloss<e (Jig. 379, * i.) In Tabanus these are
exceedingly large and broad, and are widely
expanded to encompass the wound made by
the insect with its lancet-like mandibles in the
skin of the animal it attacks. The structure
of these paraglossae is curious. On their outer
surface they are fleshy and muscular, to fit
them to be employed as prehensile organs,
while on their inner they are more soft and
delicate, but thickly covered with rows of very
minute stiff hairs (*** i) directed a little back-
wards, and arranged closely together like the
teeth of a comb. There are very many rows
of these hairs on each of the paraglossae, and
from their being all arranged in a similar di-
rection are easily employed by the insect in
scraping or tearing delicate surfaces. It is by
means of this curious structure that the busy
house-fly often occasions much mischief to the
covers of our books by scraping off the albu-
minous polish, and leaving traces of its depre-
dations in the soiled and spotted appearance
which it occasions on them. It is by means of
these also that it teases us in the heat of summer
•when it alights on the hand or face to sip the
perspiration as it exudes from and is condensed
upon the skin. The manner in which the
fluid ascends the proboscis is similar to that of
its ascent in other Haustellata, it being de-
pendent partly upon the sucking action exerted
by the application of the proboscis, assisted by
the muscular action of the paraglossae, as any one
may readily convince himself on watching the
motion of the parts in the common house-fly,
when sipping a drop of fluid, or moistening
the stolen grain of chrystallized sugar between
its paraglossae.

The palpi yet remain to be noticed. Those
of the maxillae appear to be constant throughout
the whole order. In Culex they are very con-
spicuous parts, covered with hairs and as long
as the proboscis ; they are formed of three short
basial joints and three very long ones, the fourth
joint being more than twice the length of either
of the others. In Tipula and Empis they are
also six-jointed, but of moderate length. In
Tabanus also they are very conspicuous, and
appear to be formed of two short and one very
long joint densely covered with hairs, and serve
as a cover to the base of the proboscis. In
Asilus they are short, three-jointed, and slightly
hairy (Jig. 380, h), and they are equally con-
spicuous in most of the Muscida and Syrphida,
in which they are formed in general of two short

joints and one very long one. In the common
Musca they are long and club-shaped, but in
Eristalis (fig. 379, g, h) and Volucella they are
long, slender, and sometimes covered with hairs.
The labial palpi do not appear to exist in
Diptera. Savigny believed that he had ob-
served at the base of the ligula in Tabanus a
pilose excrescence which he considered the
analogue of the labial palpi ; but although, as
Mr. Newman has remarked, the spot which
Savigny pointed out is exactly that at which
they ought to be situated if they really did
exist, we have been unable to detect them or
to confirm his opinion.

In Homaloptera the head resembles that of
Diptera. It is rounded but flattened on its
upper surface, and is so closely approximated
to the anterior margin of the prothorax into a
notch in which it is inserted, as to appear as if
separated from it only by a suture. All the
primary parts found in the head in other insects
appear to be developed in some species of this
order. Thus the epicranium in Oxypterum is
broad, distinct, and channelled along the
median line into a deep groove (fig. 381, b),

Fig. 381.

The upper and under surface of the head in
Oxypterum.

b, epicranium ; c, cornea ; d, clypeus posterior ;
d* , clypeus anterior ; e, labrum ; /, undeveloped
mandibles; g, maxilla j t, labiuin ; *, lingua.

INSECTA.

907

and the triangular suture, particularly the ante-
rior portion, which divides the epicranium
from the clypeus posterior (J), is very distinct.
At the anterior external angle of this part of
the clypeus, as in Coleoptera, are situated the
antenna (A), two short and thick porrected
organs, covered with a few long hairs, and
which, although apparently composed each of
two joints, appear to be rigid and motionless.
Immediately anterior to the clypeus posterior,
and divided from it by a distinct suture, is a
short lunated plate (d*), the clypeus anterior.
The cornua of this part are extended laterally
at the sides of the mouth, and are continuous
with a portion of the under surface of the head
(f) that bounds the labium. Between the two
cornua of the upper surface is extended a strong
and somewhat horny membrane (e\ the proper
labrum, which is continuous with a similar
membrane on the under surface (/), the labium,
which thus forms the orifice of the mouth, the
parts of which do not appear to have been
sufficiently examined in this order. Thus,
although the entrance to the mouth is indicated
by a distinctly marked labrum and labium,
scarcely more developed than in Coleoptera,
the habits of the insect require that it should
also be furnished with a strong sucking tube.
Accordingly we find that within this mem-
branous mouth are situated two curved horny
plates, a little convex on their external, but
concave on their internal surface, and capable
of being protruded to some distance. They are
directed downwards, and when approximated
form a tube analogous to that of Lepidoptera.
These parts have been described by Curtis as
the maxilla (g), of which they seem to be the
proper analogues, so that in the Homaloptera
the maxillae form the sheath or outer part of the
sucking tube. At the base of these parts,
within the cavity of the mouth, are two horny
margins fringed with dark hairs, which are
probably rudimental maxillary palpi. In the
centre of the mouth is situated an elongated
slender organ (*), which is folded at an angle
like the proboscis of Diptera, but is retractile
within the mouth, and extends backwards to
the entrance to the oesophagus. It consists of
three parts, an inferior one which is strong,
horny, and forms a groove or canal, the upper
surface of which is covered by another smaller
piece, and the two inclose between them a
third setiform organ. Upon the precise nature of
these parts we do not offer a positive opinion ;
the inferior one, which is continuous with the
inflected portion of the labium, seems to repre-
sent an elongated portion of that organ, and
the middle one probably is the lingua, in which
case the upper one would answer to a similarly
elongated portion of the labrum.

The under surface of the head is divided by
a deep incisure anteriorly, the margins of which
are covered with stiff hairs and form the lateral
boundary of the mouth. The mention (/),
described as such by Curtis, is a strong convex
plate, divided also at its anterior part by a con-
tinuation of the incisure just noticed. The
cornea (c), of an oval convex shape, are situated
more on the upper than on the lateral part of

the head, but the ocelli in this insect are entirely
wanting, unless we regard as a large ocellus
a convex plate situated in the middle of the
most posterior part of the epicranium (6*).
In the other genera of this order, as in Hamo-
bora, the head is more orbicular and less flat-
tened ; the epicranium is broad and distinct,
and the suture between this part and the
clypeus posterior is strongly marked. In
Mt lophagus, the tick or sheep-louse, the maxillae
are of considerable length, and the retractile
portion of the labium inclosing the lingua is of
considerable strength. The ocelli are present, in-
serted in little excavations in Hamobora, but ab-
sent in Melophagus. In Nycteribida the head
offers a most anomalous condition of parts, its
form being, as described by Latreille, that of a
reversed cone. We have had no opportu-
nities of examining for ourselves either the head
or parts of the mouth, which, according to
Messrs. Curtis* and \Vestwood,f are styliform,
and analogous to those of Hippobosca.

In Aphaniptera the head is compressed
from side to side, but we have not yet identified
its primary parts. Its chief characteristics are
its extreme narrowness, the situation of its
antennae, and the peculiarity of its organs of
vision, the corneae of the proper eyes being
each simple and not compound as in other
insects. The mouth is formed upon the same
general principles as in the blood-sucking
Diptera, being composed of six primary parts
adapted for piercing the skin, and occasioning
the pain which distinguishes the puncturing of
these troublesome insects.

In Aptera, all of which, like the insects of
the two preceding orders, are parasitic upon
the bodies of other animals, the mouth in one
family, the true Pediculida, is formed for suck-
ing, but in the other, the Nirmida, it is dis-
tinctly mandibulated, and approaches the usual
type of mandibulated insects.

In Hemiptera the head is often flattened and
somewhat triangular, and the mouth is rostri-
form as in some of the Diptera, but the sheath
of the organ is formed entirely by the labium
(fg. 382, k). The corneae are usually very
prominent, and are placed at the posterior
angles of the head. The epicranium is distinct,
but its occipital portion is sunk into a notch in
the prothorax. The ocelli are usually two in
number, placed on the most posterior part of
the epicranium, and are constant throughout
the order in the perfect state, but are not deve-
loped in the larva or pupa. The division of
the head into its primary parts is very distinct
in some genera. In Coreus marginatus the
epicranial suture is strongly marked along the
middle line as far as the space between the
corneae, where it joins the triangular suture which
passes outwards immediately behind the inser-
tion of the antennae, bounding the clypeus
posterior. In some specimens, but more par-
ticularly in the pupa, a faint longitudinal suture
extends forwards over the clypeus as far as the

» British Entomology, pi. 277.
t On Nycteribia, in Transactions of the Zoologi-
cal Society of London, vol. i. p. 279.

908

INSECTA.

Fig. 382.

Head of Pentatoma rufipes (Savigny).

most anterior portion of the front of the head,
where it joins with a second triangular suture
which passes outwards on each side anterior to
the insertion of the antennae, and thus divides
the clypeus anterior from the posterior. The
proper triangular suture between the epicranium
and clypeus passes backwards from behind the
insertion of the antennae along the sides of the
head as far as the margin of the cornea, thus
clearly indicating the extent of the epicranial
region, as in Coleoptera. The clypeus anterior
is distinctly marked at the front of the head (d)
as a narrow elongated plate, a little widened at
its lower portion, where it is articulated with the
labrum (e\ which is narrow, lengthened, and
ends in a point, and covers the front of the
proboscis (&), which is formed of four joints
or articulations, and is believed by Savigny to
represent the true labrum. This part, which,
in a state of rest, is concealed beneath the
under surface of the head and prothorax, forms
a cylindrical tube throughout nearly its whole
length, from its apex to its base, where it is
covered by the labrum. It incloses four dis-
tinct setae, which have been shewn by Savigny
to be the proper mandibles and maxillae. We
are satisfied of the correctness of this opinion
from our own examination of these parts, the
insertion of the muscles belonging to them
being in the basilar portion of the head, as in
all the preceding orders. But it is in Reduvius
that the parts of the head are most distinctly
marked. The occipital portion is so much
elongated backwards as to form a very distinct
neck, narrower considerably than the other
parts of the head, and the corneas are large and
protuberant and stand out from its broadest
part, while the ocelli, two in number, are also
exceedingly large and are placed on short
pedicles almost on the constricted neck-like
part of the epicranium, far behind the cornea,
and with their axis directed posteriorly. Be-
tween this portion of the head and that which
contains the true corneas is a deep transverse
impression, which seems to indicate that the
cornese and ocelli are derived from distinct seg-
ments. But one of the most marked charac-
teristics of the epicranium in this insect is the
existence of a triangular elevation or ridge,

which commences in the usual situation of the
suture in the middle line between the corneas,
and extending outwards marks the course of
the antennae. The posterior margin of this
ridge is in the usual direction of the triangular
suture, posterior to the insertion of the antennae.
Anterior to this is a lozenge-shaped plate, the
clypeus posterior, which is elevated along its
middle line, and which is continuous with a
similar elevation on the clypeus anterior. The
labrum is short, and terminates in a triangular
process, that covers the base of the proboscis
as in the preceding species. We have thus
five clearly indicated segments in the head of a
perfect insect, — the occipito-basilar segment
bearing the ocelli, the proper epicranial with
the corneas and antennae, the two clypeal, and
the labial. The proboscis consists, as in
Coreus, of four distinct articulations, which
form the labium, and correspond to the seg-
ments of the upper surface of the head, but
which are extended forwards and form a sheath
for the setiform mandibles and maxillae. In
the Hydrometrida, which connect the terrestrial
with the aquatic Hemiptera, the head is elon-
gated forwards, and the cornese, which are large
and kidney-shaped, are very protuberant. In
Gerris paludum the epicranial region is short,
but the suture is still very distinct. It divides
as usual at a point opposite to the middle of
the corneae, and passes outwards to their ante-
rior margin. The clypeus posterior is broad
and lengthened, and seems to have become
united with the anterior, and the antennae are
moved forwards to the base of the proboscis.
The Nepida have a form of head similar to
that of the Hydrometridse, but the epicranial
region (Jig. 383, d) is of greater extent. In

Fig. 383.

Upper and under surface of the head of Nepa cinerea
(Savigny.)

a, occiput ; b, epicranium ; c, cornea ; d, cly-
peus posterior ; e, labrum ;/, mandibles ; g, maxil-
lae j *, labium ; *, lingua.

the figure which we have copied from Savigny
the parts of the head are not distinguished,
but they are distinct in the insect. The epicra-
nial suture, the proper guide to a correct deter-
mination of the primary parts of the head in
every species, bounds the corneas anteriorly and

INSECTA.

909

the clypeus posteriorly, which is reduced to a
small triangular plate (d) with its apex directed
backwards. It is divided by a transverse suture
from the clypeus anterior, which forms a chief
part of the front of the head. The labrum (e\
as in the preceding species, is short and pointed,
the mandibles (J'} are long and setiform, but
Jarger than the maxillae (g), and the lingua (*),
according to Savigny's observations, forms a
short trifid process within the cavity of the
mouth, at the base of the maxillae, the covering
or sheath to the parts being formed, as in the
other species, by the labium.

In Homoptera, which are considered by
many naturalists as constituting only a division
of the Hemiptera, the general form of the head
is that of a triangle, the lateral and basilar
angles of which are occupied by the protu-
berant corneas. In the Cicadiida the epicra-
nium is short but exceedingly wide, bearing at
its sides on distinct pedicles the large project-
ing corneae similar to the pedunculated eyes of
Diopsis, one of the Diptera. The epicranial
suture is most distinctly marked. It passes
outwards from the middle line on each side
behind a large, convex, transversely striated
protuberance on the front, which is the proper
clypeus posterior, as far as the base of the
pedunculated corneae, where the antennae are
inserted immediately in front of it. The ocelli,
three in number, arranged in a triangle, are
placed on the most vertical part of the epicra-
nium, and the suture passes through the ante-
rior one. The clypeus anterior is a short
triangular plate, united by suture to the anterior
margin of the clypeus posterior. It has usually
been described as the labrum. The proper
labrum is a small pointed corneous plate, which
covers the base of the proboscis in front, and
is freely articulated to the margin of the clypeus.
It has been figured by Messrs. Kirby and
Spence* as an appendage to the labrum (appen-
dicula), which, as just shown, is the clypeus
anterior. It is often partially concealed beneath
the clypeus. The mandibles and maxillae are
usually strong corneous setae, contained within
the sheath formed by the labium. At the base
of the maxillae, concealed by the labium, are
two short membranaceous appendages, which are
probably the rudimentary maxillary palpi. They
are attached to the external under surface of
the maxillae, and are entirely concealed by
the labium. In the Fulgorida, as in Fulgora
candelaria, the epicranial region constitutes the
greater portion of the head. The large curved
process or horn on the front is derived entirely
from the epicranium. The cornea, which are
remarkably protuberant, are included within
the same region at the sides of the head, as
also are the two ocelli, which are placed one
on each side immediately before the corneae.
The antenna present a remarkable character,
being formed of three short thick joints, ter-
minated by a minute setaceous one. The third
joint, which is nearly globular, is covered with
minute protuberances, somewhat resembling
the structure of the corneae, or rather that of

* Introduct. vol. iii. pi. 6, fig. 7, a.

the antennae in the males of Eucera longicornis.
These organs are situated in deep fossae, into
which the triangular suture enters. The clypeus
posterior forms the chief portion of the front,
as in the preceding family, the clypeus anterior
a narrow plate united to the latter by suture,
and the labrum a small triangular appendage.

We have entered thus minutely into an
examination of the parts of the head and mouth
in the different orders of insects, in consequence
of the uncertainty which has hitherto existed
among naturalists with regard to the number of
segments of which the head is normally com-
posed, and also because it was necessary that
we should first show the analogous parts of the
head in the different orders before stating our
opinions with regard to the manner in which
they are developed ; and further, because from
the minuteness of the subjects and consequent
difficulty of investigation, the most ample
elucidation was necessary upon which to base
our opinions.

In our examination of the remaining parts
of the skeleton the same minuteness will be of
less consequence, because the parts are more
easily examined, and have already been identi-
fied through the excellent and elaborate investi-
gations of Audouin, Macleay, and others.

Developement of the head. — We have seen
in our examination of the perfect insect, that the
head is normally composed of four, and appa-
rently even of five sub-segments, as is proved
by the existence of the parts we have de-
scribed, which correspond to the superior and
inferior arches of that number. The first, or
most anterior of these sub-segments, is formed
by the labrum above and the ligula below • the
second, by the clypeus anterior and the men-
turn ; the third, by the clypeus posterior and
submentum. But the fourth, which has be-
come entirely atrophied, is represented above
only by the little bones of the antennae, within
the cranium, and perhaps also the corneae; and
below by that reduplicature of tegument which
forms in some insects, as in Hydrous, the large
transverse bone, or ridge between the submen-
tum and anterior margin of the gula; while the
fifth is formed by the epicranial region above,
and the gula and broad basilar region below,
the greater size of this sub-segment being the
result of its confluence with the preceding one,
the fourth, which has disappeared. The num-
ber and position of these parts are precisely
similar in the larva and the perfect insect, as
seen in Coleoptera, Hymenoptera, and the ver-
miform larvae of Diptera. In each of these
instances the greater or less distinctness of the
parts is in an inverse ratio to the more or less
perfect organization of the individual. Thus,
if we take, for example, the head of the larva of
the common Chaffer-beetle, Melolontha, the
first, second, third, and fifth sub-segments are
very distinct, and the antennae, inserted at the
angles of a strongly marked triangular suture,
indicate the situation of the fourth atrophied
sub-segment. But in the perfect beetle, as we
have formerly seen, not only have all these se-
parate parts of the larva become confluent, but
their previous existence as distinct pieces is

910

INSECTA.

scarcely to be detected. A similar condition of
parts exists in the heads of other Coleoptera.
The disappearance of one segment of the head
thus early in the larva state is in perfect accord-
ance with that progressive developement which
we know takes place in every part of the body,
and hence it was to be expected, that those
parts in which the changes first occur are those
which first entirely disappear. Hence the dis-
appearance of the fourth subsegment, which we
believe exists in the earliest stages of the larva,
and of which the antennae are the superior ap-
pendages. If we turn from this transitory
larva state of the insect to the permanent ver-
miform condition of the Annelida, the lower
Articulata, we find in the common Nereis a
condition of the head apparently analogous to
that of the vermiform larva. It is elongated
forwards, and formed of distinct segments, of
which the posterior ones, as in insects, support
the organs of vision. But these remarks on the
relations of the different parts of the head are
offered with much hesitation, because, in
Myriapods, which have usually been com-
pared with the larvae of insects, the form of the
head seems to be opposed to this mode of view-
ing its development in Articulata, since the
antennae and organs of vision are situated on
the most anterior part of a large and broad
shield, which has been considered the first
segment. But if this be correct, it will be diffi-
cult to explain the circumstance of the an-
tennas and corneas of hexapodous insects being
constantly situated posteriorly to the first three
sub-segments of the head, the labrum and clypei.
The appendages of the head, which form
part of the organs of manducation, correspond
in number to the number of sub-segments.
These parts are analogous to those which consti-
tute the organs of locomotion, when attached to
other segments of the body, as in Myriapoda,
and Crustacea. In the head of an insect the
mandibles are the proper appendages of the
fifth or basilar sub-segment, while a small but
freely articulated lobe, which sometimes exists,
as in some of the Brachelytra, at the inner
side of the mandible, appears to represent that
of the fourth. The stipes, or external portion
of the maxilla, which at its base articulates
with the cardo, and at its distal extremity is
connected with the palpus, seems to be the
proper appendage of the submentum, while
the inner portion of the maxilla, which origi-
nally appears to be a distinct part, and which
at its distal extremity supports the galea,
seems to be the proper appendage of the se-
cond sub-segment, and the labial palpi in like
manner represent those of the ligula or first.
It has been shewn by Savigny and others, that
these analogues of the organs of locomotion
undergo a very gradual change of form and use
in the different classes. In Myriapoda the ap-
pendages that belong to the basilar segment of
the head, which constitute the mandibles, are
greatly enlarged, and are directed forwards as
organs of prehension, like the chelate organs of
Crustacea and Arachnida, but are jointed and
retain the exact form of true legs. In insects
the mandibles are in like manner directed for-

wards, and are placed above those of the pre-
ceding segments, but are compressed, and mate-
rially altered in size and shape, their terminal
portions, the tarsal joints, being undeveloped,
and the tibia alone enormously enlarged, con-
stituting the whole jaw or manducatory organ,
while the basilar joints, the femur and coxa,
are lost in the under surface of the segment,
with which they have become confluent. That
this is really the case is proved by the fact that
all the muscles that belong to these powerful
organs are attached to the basilar and postero-
lateral parts of the head, in the very situations
which they must have occupied had the organs
remained free for the purposes of locomotion
or prehension, as in Crustacea, Arachnida, or
Myriapoda. That this confluence of parts has
in reality taken place is further proved by the
circumstance, that the outlines of the portions
that become united with the skull are distinctly
marked in Lucanus cervus, and still more
clearly in that of the great Hydrous (fig. 369,
o). There is a remarkable illustration of the
principle upon which the change of form in
the adaptation of these organs to a new func-
tion depends, in that curious instance of mon-
strosity in an individual of Geotrupes sterco-
rarius, described in a former page (860), in
which the tibiae of the pro-thoracic legs rme
been arrested in their development, and are
lunated like the proper mandibles, the tarsi
being entirely absent. In a remarkable insect,
Onitis aygulus, to which our attention was
directed by Mr. Shuckard, there is a further
illustration of this principle, in the permanent
condition of the pro-thoracic legs of that spe-
cies, in which the tarsi are entirely absent, and
the tibiae are lunated and terminated each by a
sharp hook. There is also a similar condition
of the same parts in other species, O. Olivierii,
O.serripes, and O.chinemis and Apelles, while
in a species of a neighbouring genus, Bubos bison,
the tibiae are considerably narrower than in the
preceding, and approach much nearer in shape
to the instance of monstrosity in Geotrupes,
thus distinctly indicating, not only that the
form of parts depends either upon excessive or
deficient developement, but also that the abnor-
mal conditions occasionally met with in some
species are permanent normal conditions in
others.

From the manner in which the appendages
of the cranial sub-segments are arranged to form
the parts of the mouth, it necessarily follows
that the most posterior pair, the mandibles,
are carried upwards, and become the superior
lateral organs ; while the maxillae obtain the
next place beneath them, and the whole are
covered in by the inferior arches of their re-
spective sub-segments, which constitute the
labium.

In all insects, the whole of the parts of the
head in the perfect individual exist in the head
of the larva, the changes which take place
being only those of size and relative position.
When the head of the larva is smaller than that
of the future imago, as in the Hymenoptera,
its increase of size j ust before the insect changes
into a nymph, and when a great portion of the

INSECTA.

911

head is found beneath the skin of the second
segment, does not depend upon its having be-
come confluent or united with a portion of that
segment, but upon the development of those
parts which already existed in it in the larva, so
that the diminution which the second or pro-
thoracic segment undergoes is simply an atro-
phied condition, which results from the deve-
lopment of the adjoining parts, and not from
an actual union or coalescence with them ;
since in every instance in which apart becomes
confluent with an adjoining one, it loses its dis-
tinctness of form and character, and does not
remain free as when simply atrophied, or ar-
rested in its developement. But when the head
of the perfect insect is smaller than that of the
larva, as in the Lepidoptera, the extent of the
pro-thoracic segment is not diminished, unless
encroached upon from behind by the enlarge-
ment of the meso-thorax,

The thorax is that region of the body
which immediately follows the head, and bears
all the organs of locomotion in the perfect
insect. It is always composed of three very
distinct segments, first, the pro-thorax, which
bears the first pair of legs ; second, the meso-
thorax, which bears the first pair of wings and
second pair of legs ; and third, the meta-
thorax, which bears the second pair of wings
and third pair of legs. Besides these seg-
ments, which are analogous to the second,
third, and fourth in the larva state, there is also
another, the fifth segment of the larva, which
enters in part into the composition of the thorax
of the perfect insect, and forms its connexion
with the abdominal region. We have already
alluded to this in our account of the changes of
the larva, (p. 877, 8,) during which we have
shewn that at least one segment of the body
always becomes atrophied, and very frequently
almost disappears, and that this segment is the
fifth. But we have not there sufficiently ex-
plained that this segment belongs partly to the
thoracic and to the abdominal regions, on which
account we propose to designate it the tho-
racico-abdominal segment, and consequently the
number of segments of which the abdomen is
composed will depend upon whether or not we
include this in that region. For our own parts
we prefer to consider it as forming a most dis-
tinct part, for reasons which we shall presently
explain. Now it has been shewn by M. Au-
douin, in an admirable and elaborate series of
investigations, that each segment of the thorax
is normally composed of four sub-segments,
which sub-segments or annuli are each formed
of distinct parts, one upper or dorsal, one lower
or pectoral, and two lateral. The four annuli
thus formed are easily demonstrable on the
upper surface of each thoracic segment, but are
less readily detected on the pectoral or under
surface, in consequence of the parts having
there become confluent, in order to afford a
greater degree of solidity to the skeleton ; and
in consequence also of the diminished extent of
the pectoral as compared with the dorsal sur-
face, which, as before explained, (page 877,) is
dependent upon the greater extent of change
that takes place on the pectoral than on the

dorsal surface during the metamorphoses of the
insect. The parts capable of demonstration in
each segment, according to the views of Au-
douin, are, on the upper or dorsal surface, the
pratscutum, scutum, scutellum, and post-scutel-
lum ; on the inferior or pectoral surface a single
piece, the sternum, and on the lateral two
pieces, the episternum and epimeron on each
side ; in addition to which there are also two
evanescent pieces, which are of considerable
size in some species, but scarcely distinguish-
able in others. These are the paraptera, por-
tions of the thorax not articulating with the
sternum, but with the episternum, anterior to
each wing, and the trochantin, articulating with
the epimeron and coxa of the leg, the parap-
tera of the pro-thorax being, according to
Audouin, absent. Hence the number of
pieces he describes as forming the external
thorax are ten for the pro-thorax, twelve for the
meso-thorax, and a like number for the meta-
thorax, making in all thirty-four pieces. These
are parts capable of being demonstrated, if we
regard each sternum as formed of two trans-
verse pieces united, and corresponding to the
episterna and epimera. But as remarked by
Mr. Macleay,* each sternum at the maximum
of development ought to be regarded, like the
dorsal surface of each segment, as composed
of four transverse sub-segments united longitu-
dinally, and the sides of the same number. If
then the four portions on the dorsal surface of
each segment, and the sternum on the under,
be also divided in the median line, the number
of pieces in the thorax will amount to seventy-
two. But this number, as Mr. Macleay has
well remarked, can never appear together in
any insect, owing to the great extent to which
some parts are developed, and the consequent
atrophy of others. At the same time it must
be observed, that if we adopt this, which ap-
pears to be the correct theoretical mode of con-
sidering the subject, the number of pieces
which enter into the composition of the thorax
is in reality greater than that given by M.
Audouin, who has not described any parts be-
longing to the pro-thorax as analogues of the
paraptera of the meso- and meta-thorax, but
which we think may be found in a pair of those
little detached plates that exist in the articu-
lating membrane between the head and pro-
thorax in Coleoptera, and which have been
described by Straus Durckheimf as pieces
jugulaires, and conceived by him to represent
the remains of two distinct segments, situated
originally between the head and pro-thorax, but
which have disappeared during the transforma-
tions. But we are more inclined to consider
them as detached portions of the pro-thorax
than as remains of distinct segments, since we
are totally unaware that any such disappear-
ance of segments ever takes place between the
head and pro-thorax ; the head or first segment
of every Coleopterous larva being the proper
representative of the head of the perfect insect ;
and the second segment of the larva being in

* Zoological Journ. vol. i. p. 177.
t Considerations Gen. &c. p. 75.

912

INSECTA.

like manner that of the pro-thorax, the change
which takes place between these two segments
during the metamorphoses being chiefly a
shortening of the sternal surface of the pro-
thorax, or second segment, occasioned by a re-
flexion inwards of a portion of the external
tegument, to form the articulation as in other
insects. If, therefore, we include the jugular
pieces of Straus as the analogues of the parap-
tera, the external surface of each of the three
thoracic segments will be found to consist of
twelve primary and readily demonstrable
pieces, making in all thirty-six, the number
which we believe always enters into the compo-
sition of the thorax, as formerly stated by M.
Jurine. But it is probable that the parts de-
scribed by M. Audouin, and recognised by our-
selves, are not identical with those of that
author, since the scutum of the meso-thorax in
Hymenoptera, as will presently be seen, and as
formerly pointed out by Mr. Macleay,* is not
only divided in the median line, but its two
sides are also separated by a deep longitudinal
fissure each into two parts, the outermost of
which Mr. Macleay designates parapsides.
This division of the scutum of the meso-tho-
rax, if constant in the other orders, would raise
the number of distinct pieces to thirty-eight.
M. Audouin, who adopts the name given to
these parts by Mr. Macleay, states that although
he was previously well acquainted with this
division of the scutum in Hymenoptera, he
did not assign names to the pieces because he
considered them rather as mere divisions of the
scutum itself than as distinct parts of the ske-
leton. The existence of these pieces, therefore,
in Hymenoptera, is a circumstance connected
with the number and identification of the nor-
mal parts of the skeleton, which, it must be
acknowledged, offers not a little difficulty, be-
cause if it be ultimately found that these, which
are so distinct in some genera, the Chrysidida, be
in reality normal parts of the mesothorax which
are thus shown to exist as such only by this
segment being developed to its maximum ex-
tent in this Order, it must be admitted that
they also exist primarily in all other insects,
not merely in the mesothorax, but in the pro-
and metathorax, so that the dorsal surface
of each thoracic segment must be regarded as
formed not of four but of sixteen parts, the
praescutum, scutellum, and post-scutellum
being each divided in the same manner as the
scutum into four pieces, first by a median line
into two halves, and these again divided late-
rally into two others. The two middle pieces
would then constitute the notum, or dorsal sur-
face of each segment, and the two lateral the
purapsides. An equal number of parts must
then be recognised as entering into the forma-
tion of the ventral arch of each segment. Each
middle or sternal piece, formed of four con-
secutive pieces, analogous to those of the dorsal

* Zoological Journ. vol. i.

arch, and divided in the median line, would
correspond to the middle series of dorsal pieces,
the proper notum, and a like number on each
side of the sternum would correspond to the
lateral portions of the dorsal arch, the parap-
sides. Of these lateral pieces of the ventral
arch, three are already known in each segment,
as we shall presently find, the parapteron, epi-
sternum, and cpimcron. But since there has
never yet been actually found even an approxi-
mation to this multitude of pieces in the dorsal
surface or arch of the thorax, we prefer for
the present to follow the views of M. Audouin,
and with him to regard the parapsides as only
detached portions of the scutum in Hymenop-
tera, in which the development of the meso-
thorax is carried to its greatest extent. It must
be acknowledged, however, that in admitting
the parapsides to be only detached portions 01
the scutum, and not primary parts, the same
thing may be urged with regard to some of
those which, according to M. Audouin's views,
are believed to be normal structures. But this
objection seems to be replied to by the fact
that the pieces described by M. Audouin are
almost always found to exist most distinctly
marked, whether developed to a greater or less
extent, in the generality of insects. Thirty-
six, therefore, we regard as the number of
the distinct external parts of the thorax. Yet
even this is more than has been recognized
by others who have attended to this subject.
Thus Knoch describes only twelve, Chabrier
and Burmeister, eighteen ; Kirby and Spence,
twenty ; Straus Durckheim, twenty-two ; and
Macleay, fifty-four. But whatever be considered
the exact number, they are never all distinctly
developed in every insect, owing to the causes
before explained with reference to the greater
developement of some parts than of others, al-
though some trace of the existence of the atro-
phied pieces usually remains. It is owing, also,
to the same causes, that the actual position of
the parts becomes altered in different insects,
although their relative position continues the
same.

Very much confusion has arisen in the de-
scriptions of the parts of the thorax, in conse-
quence of various authors applying different
names to the same parts in different insects,
and also from the uncertainty which, as above
shewn, exists in the opinions of authors with
regard to the exact number of pieces that enter
into the composition of the thorax. In order,
therefore, to obviate as much as possible this
serious inconvenience and difficulty in recog-
nizing the parts, we shall add a table of the
names given to them by Audouin, with refe-
rences to the delineations of them by that
author, and also the synonyms used by other
writers. In doing this we shall also adopt
Burmeister's very convenient names for the
upper and under surface of each thoracic seg-
ment, which are equally simple, and distinctive
of the parts to which they are applied.

INSECT*.

913

- . —

— vj rJl — i. y; —

fill"ll" * li"il

S. — — M £- ^

VOL. II.

3 0

914

INSECTA.

The pro-ttorax, as we have stated, is com-
posed of four sub-segments, which on its upper
surface, or pro-notum, are generally confluent,
more particularly in Coleoptera, and form a
smooth, uniform, and often very broad surface.
In shape, the pro-notum is usually more or less
quadrate and convex, with its sides arched and
dilated. In many species, as in some families
of Coleoptera, Orthoptera, and Homoptera,
the pro-notum is larger than the corresponding
part of any segment of the body, being consi-
derably broader and longer than the head.
This is the case more especially in those in-
sects which are much employed in burrowing,
as in Gryllotalpa, Geotrupida, Copridte, and
Silphida. Sometimes, as in the Cercopida, it
is enormously enlarged. In Membracis Joliata
it is developed in the median line into an ele-
vated crest like that of a helmet, which is not
only extended forwards so as completely to
conceal the head, but also laterally and back-
wards over the whole body. In others of the
same family, as in Ledra, it resembles an acute
triangle, its sides being developed into two ob-
tuse processes, while it is elongated backwards
like an acute spine, which completely covers
the abdomen. In other instances, as in Dynas-
tid<£, (Jig. 333,) it is developed into a strong
horn or process, which is as long as the whole
body. In each of these instances, the abnormal
form and size depend either upon the exces-
sive development of the whole of the sub-
segments, as in Gryllotalpa, or upon one or
more of them, as in Dynastes, since in those
species in which the parts of the pro-notum are
all nearly equally developed, and are of moderate
size, their lines of separation are very distinctly
marked, as in the common green grasshopper,
Acrida viridmima. The pro-sternum, or under
surface of the pro-thorax, is considerably shorter
than the pro-notum. In Dyticus circumflexus
{fig. 384 A), the species selected by Audouin

Fig. 384.

A, under-surface of the first segment of the
tJuyrax or pro-sternum of Dyticus circumfiexus,
( Audouin) ; 2 g, pro-sternum ; 2 /, episternum ;
2 h, epimeron ; 2 s, ante-furca or ento-thorax.

for the purpose of illustrating the anatomy of
the thorax in Coleoptera, it is divided into
three distinct pieces. The sternum, or largest
piece, (2g,) is situated in the middle line, and
is of a triangular form. It is extended on
each side, at the anterior part of the segment,
into two processes, which articulate at their ex-
tremities by a distinct suture with the produced
margins of the pro-riotum. Posteriorly to these
it is developed in the median line into a spine
or crest, on each side of which it is hollowed
out to form part of the acetubula, into which the
coxae of the anterior legs are inserted. External

to each acetabulum is a broad and somewhat
triangular-shaped plate, the episternum (2^').
This part is united by suture at its anterior
margin to the extended part of the sternum, by
its superior border to the dilated margin of the

fro-notum, and by its posterior to the epimeron.
t is a very distinct piece, and does not enter at
all into the formation of the acetabulum, as it
appears to do on a cursory examination. The
third piece, the epimeron (2 A), is that which is
always connected with the ro.ro, or basial joint
of the leg. In this species it is a narrow plate,
situated posteriorly to the episternum, and
forms the posterior margin of the sternal surface
of the pro-thorax. At its sternal end it has a
short process, that forms the outer margin of
the acetabulum, and articulates both with the
sternum and episternum. It is probable that a
portion of this process is the proper trochantin
of the leg on each side, since the part, which
has been described by Audouin as the tro-
chantin in the meso- and meta-thoracic seg-
ments, has not been delineated in his drawing
of the pro-thoracic. In Dyticus marginalis
there is a mark upon the process which resem-
bles a suture, and which still further induces us
to believe that this part is the analogue of the
trochantin. Within the cavity of the pro-
thorax, extending upwards from their attach-
ment to the pro-sternum, are two bony rami,
which at their inferior extremity are developed
into two rounded plates (2 s), that form a col-
lar, or leave a circular hole between them for the
passage of the spinal cord. They constitute
the ante:furca, the ento-thorax of Audouin.
These are the parts that enter into the formation
of the pro-thorax, exclusive of the anterior pair
of legs, the only appendages of this segment.

Fig. 385.

PartoftJiemeso-thorax. (Audouin.)
A, meso-sternum ; 3 a, praescutum ; 3 b, scutum ;
3c, scutellum; 3 d, post-scutellum ; 3 e, parapte-
ron; 3 g, meso-sternum ; 3/, episternum ; 3 h, epi-
meron -, 3 s, medif urea, or ento-thorax.

The meso-thorax, (fig. 385,) or third segment
of the body, is usually less developed in this
order than the pro-thorax, with which it is freely
articulated by a strong membrane. It is, as its
name implies, the middle portion of the tho-
rax, and in most instances its division into four
sub-segments is distinctly marked on its dorsal

INSECTA.

915

surface, or meso-notum. It is the segment
that bears the elytra and middle pair of legs.
The first piece, the prtfscittitw (3 </), is in ge-
neral narrow and transverse ; it is very readily
overlooked, being in most cases bent down-
wards to form the mcso-pfiragma, the anterior
boundary of the segment. The second piece,
the scutum (3 />), is a much broader and very
distinct corneous plate, and may be regarded,
perhaps, as the most important division ot the
meso-notum, since it is to this that the ante-
rior pair of wings, the elytra, are articulated.
It is followed by the scutellum (3 c), which
also is a very important division. Like the
scutum it is a broad piece, that covers the pos-
terior part of the meso-notum, and extends
on each side to the base of the elytra, the
a(ut<e, which are continuous with them, being
attached to its margin. It is developed in the
middle line into a remarkable elevated plate,
that is shaped like an armorial shield, and
is so exceedingly large in some species, that
it covers nearly the whole of the body. In
Dyticta, and most of the Coleoptera, it is the
small triangular plate which is situated be-
tween the elytra, at their base, and is supposed
to be of use in keeping these organs steady
during flight. The fourth and last piece of the
meso-notum, the pvst-scutellitm (3 rf), like the
prae-scutum, is narrow and inconspicuous. It
is situated immediately behind the scutellum,
and is the posterior boundary of the meso-
notum. These parts together form the dorsal
surface of the first wing-bearing segment,
which is developed to as great an extent on its
under as on its upper surface. The meso-
notum is most fully developed in those insects
in which the anterior pair of wings are the
largest, as in the Lepidoptera, Hymenoptera,
and Diptera, while in those in which the chief
organs of flight are the posterior wings, as in
the Coleoptera, it is the smallest of the three
thoracic segments. The meso-sternurn (Jig. 385,
A), like the pro-sternum, is formed by a strong
middle piece, the proper sternum of the seg-
ment, (3 £,) which is developed laterally into
two processes, behind which the coxae of the
middle pair of legs are articulated, and anteri-
orly and laterally the episterna (3/) and epi-
mera (3 h). Each episternal piece is a broad
elongated plate, which forms the anterior part of
the meso-sternum. It is attached to the ante-
rior margin of the lateral sternal process, so
that its actual position is a little altered, the
corresponding part of the pro-thoracic segment
being situated behind the process of the sternal
piece. This is a circumstance which occa-
sionally takes place in the development of
every part of the skeleton, the actual position of
one part being altered by the greater or less de-
velopement of another, while the relative posi-
tion of each part always continues the same.
Thus, although the epislernum is situated more
anteriorly in the meso- than in the pro-sternal
surface, it still continues to be articulated with
the sternum. The epimeron (3 h} is situated
behind the episternum. It is a narrow elon-
gated plate, that forms the posterior portion
of the meso-thorax, and is united to the anterior

of the meta-thorax. At its superior extremity
it is much broader than at its inferior, which is
articulated with the extremity of the sternal
process, and also with the coxae of the middle
legs. At the anterior border of the episternum
there is a very narrow but distinct plate, the
parapteron (3 e). This piece, which is con-
nected especially with the wings, undergoes a
great change of form and size in the different
orders. In the Coleoptera it is narrow and
evanescent, but as we shall hereafter see, is
largely developed in the Lepidoptera. It is
evidently a normal portion of the skeleton, but
has only been described by Audouin as found
in the meso- and meta-thoracic segments. We
have before alluded to the existence of two
detached pieces in the connecting membrane of
the pro-thorax and head, which we regard as
the analogues of these pieces of the meso- and
meta-thorax. If this be correct, the relative
position of these to the other parts of the pro-
sternum is precisely similar to that of the same
parts of the meso-sternum. The wedifurca,
(3 s,) or ento-thorax of this segment, is at-
tached to the internal surface of the sternal
piece, as in the pro-thorax. It is formed by
two ascending rami, which are larger and
longer than those of the pro-thorax, but like
them are developed into two expanded por-
tions, which are approximated together and
form an arch, under which the nervous cord
passes in its course to the meta-thorax.

Fig. 386.
A

Parts of the meta-thorax. (Audouin.)
A, meso-sternum ; 4 a, prae-scutum ; 4 b, scutum ;
4 c, scutellum ; 4 d, post-scutellum ; 4 e, parapteron ;
4/, episternum ; 4g, meta-sternum ; 4 A, epimeron;
4 *, post-furca.

The meta-thorax (fig. 386) is the fourth seg-
ment of the body, and the third of the thoracic
region. Its upper surface, or meta-notum, as
in the preceding segments, is divided into four
portions. The prtEscutum (4 a) is a narrow
transverse plate, which is bent down at its ante-
rior margin like the prsescutum of the meso-
notum, to form the meta-phragma, and is ex-
tended on each side as far as the paraptera,
bounding the insertion of the wings. In the
middle line it is extended backwards upon the
dorsal surface as far as the scutellum, thus di-
viding into two parts the second piece, the
scutum, (4 &,) \vhich, like the corresponding
part of the meso-notum, is connected with the

3 o 2

916

INSECTA.

wings of the segment. This connexion is the
great characteristic of the scutum in all insects.
The next piece, the scutellum, (4 c,) is a much
broader plate, and is extended across the whole
surface of the meta-notum. Like the corre-
sponding piece of the meso-notum, it bears on
the middle line an excavated shield-shaped
plate, and is connected at its external margin
with the borders of the wings. The last piece,
the post-scutellum, ("4 </,) which, although nar-
row like the prsescutum, is a strong horny plate
that extends on each side, and like the scutel-
lum, is connected with the wings. Its posterior
margin is bent down to assist in forming the
division between the thorax and abdomen, and
is connected with the remains of the atrophied
fifth segment. The meta-sternum (A) is fre-
quently the most developed portion of the
meta-thorax, particularly in those insects
•which, as Audouin has observed, are especially
walkers. In Dyticus, the middle piece, the
proper sternum (4 g), is a smooth expanded
plate, which is produced at its anterior part into
a spine, that articulates with the emarginated
extremity of the crest of the meso-sternum. On
each side of the spine it is developed into a
broad, smooth, triangular plate, to the anterior
border of which is articulated the episternum,
(4J',} also of a triangular form. This piece oc-
cupies the anterior lateral region of the meta-
sternum, arid the parapteron, (4 e,} which is
situated immediately beneath the insertion of
the wing, is articulated with its superior border.
The epimeron (4 //) of this segment is exceed-
ingly small, and appears at first to be removed
from its proper situation, being carried upwards
to the side of the body by the enormously ex-
panded coxa (T). But although removed from
its usual situation, and reduced in size, it still
retains its characteristic distinction, that of arti-
culating with the coxa, and also with the tro-
chantin (?), (/c,) which, although minute, is in
connexion both with the coxa and epimeron.
The meta-j'urca, or ento-thorax of this segment,
(4 s,) is an exceedingly large and important
piece, shaped like the letter Y. It is attached
at its posterior extremity to a thin vertical
plate, which is situated between the united coxae
of the legs of this segment, and it is also arti-
culated with the posterior part of the internal
surface of the meta-sternum. From this at-
tachment it is extended upwards and forwards
into the middle of the meta-thorax, where it is
expanded on each side into two broad curved
plates, to which the muscles of the posterior
legs are attached. In the middle line it is
grooved, and at its anterior part forms a par-
tially covered canal, along which the nervous
cord is transmitted in its course to the abdo-
men. Besides the parts now described, there
are also two curved plates reflected inwards
from the posterior margin of the meta-sternum,
where it is articulated with the coxse, and also
one central vertical one, which arises in the me-
dian line from the interior surface of the ster-
num, and which appears to be the proper inte-
rior sternal ridge. Each of the posterior coxa
is also furnished with a broad plate, which is
situated within the meta-thorax, on each side of

the attachment of the post-furca. These parts
afford attachments for the muscles of the legs.

Fig. 387.

Skeleton of Hydrous piceut .

A, pectoral surface ; B, dorsal surface ; 2, pro-
notum j 2 a, prosteraum •, 2 ft episternum j meso-

INSECTA.

917

i ; 3 a, prsescutum ; 3 b, scutum ; 3 c, scutel-
lum; 3 d, post-scutellum ; meso-sternum ; 3 \ g, ster-
num ; 3 h, episternum ; 3/, epimeron; 3 », crest of
the meso-sternum ; 3 e, parapteron ; 3 k, tcochan-
tin ; 4, meta notum ; 4 a, praescutum ; 4 b, scu-
tum ; 4 c, scutellum ; 4 d, post-scutellum ; 4 e,
parapteron; meta-sternum ; 4 f, episternum; 4 g,
meta-sternum ; 4 h, epimeron ; 4 t, crest of meta-
sternum ; 4 A, trochantin (?) ; 4 i, coxa ; 4m, tro-
chanter ; 4 n, femur; o, tibia; p, tarsus; q, un-
guis.

These segments constitute the proper thorax
of the insect, and the parts we have described
are found in nearly all the Coleoplera, the most
perfect species ; although, as before stated, they
are sometimes greatly modified in shape, and
varied in size and position, in order that the
body of the insect may be adapted to its pecu-
liar habits. Thus in the great water-beetle,
Hydrous piceus, (Jig. 387,) which in its general
appearance and mode of life very nearly resem-
bles the Dyticus, and not only burrows deeper
into the mud at the bottom of stagnant waters,
but is also accustomed to float among the
weeds on the surface to bask in the sun, the
form of the sternum is admirably adapted to
its habits. The sterna of the meso-thorax and
meta-thorax are not only both armed with a
strong keel like a boat, but the two are firmly
articulated together, which enables the insect
more securely to float on the surface of the
water, and thus afford additional strength to its
whole body for the accomplishment of its ob-
ject. But in the Dyticus, to which it is of
the utmost consequence to be able to swim
with the greatest rapidity, and turn with facility
in the water, in the pursuit of its living prey,
the pro-sternum and meso-sternum only are
slightly keeled, while the meta-sternum is
smooth, and the sides of the body are acute,
and offer the least possible resistance to its
movements. In addition to this, to afford suf-
ficient strength to the body, together with faci-
lity of motion, the sternum of the meta-thorax
is produced in front into a short spine, which is
inserted into a notch in the posterior part of
the meso-sternum ; while the coxae of the poste-
rior pair of legs upon which the chief efforts in
swimming depend, although enormously en-
larged to afford sufficient space for the inser-
tion of the muscles, are flat and smooth like the
rest of the under surface of the body, in order
that they may not oppose the slightest impedi-
ment to the motions of the insect. The different
forms of the coxae (7) and of the acetabula (4 A:),
into which they are inserted, have also a refe-
rence to the habits of the species. The large
posterior coxae of the Dyticus are immoveably
united by suture to the posterior margin of the
meta-sternum, because, in this insect, the pos-
terior pair of legs being especially designed for
swimming, and their motions consequently
being almost wholly in one direction, addi-
tional strength is afforded to these organs by the
immobility of the coxae. In the Hydrous, in
which all the legs are employed in walking, as
well as in swimming, the coxae are freely
articulated in their respective acetabula,
and each one is supported in part by the tro-

chantin (?), (ft), which is more developed than
in the other insect.

The strength of the body depends much upon
the size of the thoracic segments, and the firm-
ness of union which exists between them. Thus
in those species which are more especially em-
ployed in walking, in flying, or in swimming,
the meso- and meta-thoracic segments are the
largest. If the insect be aquatic, the largest
parts, as we have seen, are the sternal surface of
the meta-thorax, and its coxae ; but if, on the
contrary, the habits of the insect be aerial, then
the dorsal surface of the segment is larger than
the sternal. In those insects which are mostly
employed on the ground in running or walking,
as the Carabidte, Geotrupida, Copridz, and
Lucanidtf, the meso- and meta-thoracic seg-
ments are often anchylosed together, to give
greater strength to the whole body. This is
particularly the case in Lucanus cervus (fig.
388), in which the small sternum of the meso-
thorax (3 g) is firmly anchyclosed to the enor-
mously enlarged sternum of the meta-thorax.
The reason for this is not merely to afford
greater stability to the meta-thorax and its
wings, upon which entirely devolves the labour
of supporting this unwieldy insect during
flight, but also to give greater strength to the
whole body, during the efforts of the insect to
strip off the bark from the smaller roots and
branches of trees, to obtain a flow of the juices
upon which it subsists. That such is the reason
for this anchyclosed condition of its segments
is evident from the circumstance, that it occurs
not only in those insects which require great
muscular power during flight, but also in those
which are much accustomed to laborious efforts
in tearing, in burrowing, or in running. In
these, also, the acetabula (2 r, 3 r), are exceed-
ingly deep, and almost entirely enclose the
coxae within them, so that while the limb can
be rotated freely in almost every direction, a
dislocation of it is utterly impossible. The ace-
tabula are situated on each side of the poste-
rior part of the sternum, in each of the three
thoracic segments, and in general are formed
by an approximation of the sternum and epi-
meron, and sometimes, also, of the epister-
num, as in the Dyticm (fig. 384, A). When,
as in this instance, the episternum enters
largely into the formation of the acetabulum,
the epimeron is carried backwards, and forms
the postero-lateral boundary, the episternum
the antero-laieral, and the sternum the anterior
boundary, so that the acetabulum is formed by
the junction of three articulating sutures, and
completely surrounds the coxa. This consoli-
dation of parts gives an amazing increase of
strength to the segment in which it occurs, and
is one of the circumstances which enables the
insect to exert a degree of muscular power
which is sometimes truly astonishing. It oc-
curs in general in the pro-thoracic segment, as
in Lucanus, (388, 2,) Geotrupes, Ateuchus, and
other Lamellicornes. A similar condition of the
acetabula of the meso-thorax exists also in the
same insect (3 r). But instead of the posterior
wall of the cavity being formed by the epi-

918

INSECTA.

Fig. 388.

Internal skeleton of Lucamis census.

meron, it is formed by a reflection inwards of
part of the anterior margin of the meta-sternum,
(4 q,} with which the meso-sternum has become
anchyclosed, and the episternum and epimeron
form the lateral boundary of the cavity.
The great strength of limb required by insects
for other purposes than those of locomotion, be-
longs especially to the first and second pair of
legs, and consequently the articulations of
these with the body are required to be most
secure. We have seen that in the aquatic in-
the posterior pair are almost solely em-
ployed m swimming, and in the terrestrial in-
sects they are in like manner employed chiefly

in locomotion. The necessity, therefore, fot d
consolidation of the walls of the acetabula,
into which they are inserted, is not so great as
in the preceding instances, and consequently we
find that those for the posterior pair (4 r) are
formed by the posterior margin of the expanded
meta-sternum in front, and the consolidated
margin of the inferior surface of the fifth or
thoracico-abdominal segment behind, reflected
inwards and upwards, and loosely articulated
in the median line with the sternum, thus al-
lowing of the freest motion to the coxae, the
sides of each being formed by the epimeron.
But in insects which move with a sudden
effort, as in jumping, and in those that employ
the hinder legs as prehensile organs, like the
Coprida, Ateucln, and others, these legs, like
the anterior ones, are inserted into deep
acetabula.

The abdomen, or third division of the body,
is entirely destitute of organs of locomotion.
It contains the chief part of the digestive, re-
spiratory, circulatory, and generative systems,
and, like the thorax, is composed of distinct
segments. These are nine in number, if the
fifth segment of the body, which almost disap-
pears during the change to the perfect state, be
included. This segment, however, we prefer
to consider as a distinct part, so that the abdo-
men consists certainly of eight segments, be-
sides the anal appendages. Each segment is
formed of one dorsal and one ventral plate,
connected at the sides by a distinct membrane.
Only five of these plates are in general to be
observed on the under surface, but some trace
of the whole number is always seen on the
upper, and also at the sides (jig. 388). This
arises from the circumstance that a portion of
the ventral surface of the first three segments of
the larva is employed in forming the under
surface of the anterior part of the abdomen of
the perfect insect, the change in Coleoptera, as
in other insects, being carried to a greater ex-
tent on the under than on the upper surface of
the body. One segment, also, the anal one,
becomes partly removed from the others at the
posterior part, and is retractile within the ab-
domen, so that there are only five connected
segments to the ventral surface, but nine on the
upper. The form of the abdomen is in general
somewhat triangular or oval in Coleoptera, its
basial part being of the same width as the tho-
rax. Each segment is freely moveable, the an-
terior part of one being retractile within the
posterior of another. At the external margin
of each dorsal plate, in the membrane that
connects those of the upper with the under
surface, there is an oval corneous ring, the
xpiraculvm^ or breathing orifice, which commu-
nicates internally with the organs of respiration.
In most of the Coleoptera the abdomen is co-
vered by the elytra, but in some species it is
exposed, as in the oil-beetles, rove-beetles, and
ear-wigs. In the latter instances it is furnished
at its extremity with strong forceps, which
appear to be analogous to parts which we are
about to consider more particularly in other
insects.

INSECTA.

919

In Orthoptera the structure of the thorax is
similar to that of the Coleoptera, but it is un-
necessary to describe it more minutely at pre-
sent, a greater interest being attached to the
whole skeleton of those insects which undergo
metamorphoses, more particularly the Hymen-
optera and Lepidoptera, than to those in which
these interesting changes do not take place.

The structure of the thorax in Hymenoptera
merits considerable attention, from the circum-
stance that it is scarcely yet decided whether it
be composed only of three distinct segments of
the larva, or whether a fourth one enters in part
into the composition of it. We have seen that
in the larva state in this order there are fourteen
distinct segments, besides an anal tubercle, and
that during the transformations the body is con-
stricted in the fifth segment, which seems to
form the connexion between the thorax and
abdomen. According to the usually received
opinions, the true thorax is always composed of
but three segments, but M. Audouin believes
that this is not strictly the case in Hymenop-
tera, and has endeavoured to shew that in this
orderthe posterior portion of the thoracic region
is part of a segment that belongs to the abdo-
men. Mr. Macleay, on the contrary, contends*
that this is not an additional segment, but is in
reality part of the fourth or meta-thoracic seg-
ment of the larva. In this opinion he is sup-
ported by Burmeister and Westwood, while the
views of Audouin are advocated by Latreille
and Kirby and Spence.

The pro-thorax, which is a large segment in
the larva state, is greatly reduced in size in
the perfect insect, owing to the operation of
causes which take place during the metamor-
phoses. But it is not so much reduced as in
the Lepidoptera and Diptera. The boundaries
of this segment in Hymenoptera, like those of
the meta-thorax, are a subject of dispute among
naturalists, owing to the segment in the perfect
state being divided into two distinct parts, the
first of which is articulated with the head, and
freely moveable upon the other, which is at-
tached firmly to the meso-thorax. The piece
articulated with the head is believed by Kirby
and Spence to represent the entire pro-thorax,
or second segment of the larva. It bears the
first pair of legs, and in the winged species is
readily detached from the other, which is the
collare of those authors, who, on account of its
being attached to the great meso-thorax, believe
it forms a part of that segment. This, as Mr.
Macleay has shewn, is not the fact, as is proved
by the circumstance that in the Ants and other
walking Hymenoptera it is readily removed
from the meso-thorax, and is united to the
anterior piece, which bears the first pair of legs ;
while he suggests that the reason for its being
attached to the meso-thorax in the flying spe-
cies, is to give strength to that segment, and
support the wings.f We have convinced our-
selves of the correctness of this view of the
subject by an examination of the parts in Ich-
neumon atropos, (Jig. 389, 390,) in which the

* Zoological Journal, vol. i. p. 145. et seq.
t Op. cit. p. 168.

Fig. 389.

Ichneumon Atropoe.

2, pronotum j 3 b, scutum of meso-thorax ; 3 c,
scutellum ; 3 e, parapteron j *, wing ; 4 b, scutum
of meta-thorax ; 4 d, freuum j 4 e, scutellum j * %
spiracle j /, coxa.

two pieces are freely separable. The pra-scutum
and scutum of the pro-notum are exceedingly
short and evanescent, as described by Mr.
Macleay m Polistes, the prae-scutum being
merely a ligamentous membrane that unites
this segment to the head. The scutum is a
short plate that forms the upper surface of the
anterior portion of the segment, the sides being
formed, as we shall see, by the epimera and
episterna (2 g). The posterior piece, the scutel-
lum, is of considerable size laterally (2 A), but
it is short on the upper surface (2), and is deeply
notched to fit it to the anterior part of the meso-
notum, its two sides being produced into a some-
what triangular shape, and wedged in between
the scutum of the meso-thorax and the epister-
num on each side. The post-scuteltum exists
only as a rudimentary membrane, which assists
to mark the proper boundary of the pro- thorax,
this being, as Mr. Macleay has observed, one
of the proofs that the scutellum now described
does not belong to the meso-thorax, while the
non-existence of a similar membrane, or
phragma, between the two portions of the pro-
thorax itself, affords an additional reason for
considering these but as parts only of one
segment.

The mcso-notum is the most largely deve-
loped portion of the thorax in this order, as in
Diptera and Lepidoptera. It is a convex elon-
gated plate that covers nearly the whole of the
dorsal surface of the thorax. The prae-scutum
is a vertical piece, developed inwards to assist
in the formation of the pro-phragma that di-
vides the collar from the scutum. The scutum
(3 6) is broad, convex, and lozenge-shaped.
At its sides are developed the anterior pair of
wings, and at its base, which is slightly trun-

920

INSECTA.

eated, is an elevated scutellum. It is marked
©n the median line by a longitudinal suture,
and in some genera by two others, one on each
side of this. In the Chrysididae, these lateral
markings completely divide the scutum into
three distinct pieces, the two outermost of
which are those to which Mr. Macleay has
given the name of parapsides, and which he
somewhat curiously suggests may probably be
a third pair of paraptera,* those of the pro-
thorax, pushed out of their proper place. But,
as remarked by Audouin,f in his notes to Mr.
Macleay's paper, were this the case, it would
indeed be a most singular displacement ; at the
same time we are compelled to acknowledge
that we hesitate to admit the explanation which
M. Audouin has given of the nature of these
pieces. He regards them as mere divisions of
the scutum, and not as elementary parts. If
this be the case, other parts that are consi-
dered as distinct pieces may with equal justice
be regarded as only occasional divisions of
more important ones. They seem rather to in-
dicate the division of the skeleton into a much
greater number of parts than are at present
recognized in it. We are led to this opinion
from the circumstance that these markings
exist more or less distinct in very many species.
We have found them very distinctly in the
dried skeleton of Bombus terrestris. The scu-
tellum (3 c) is of large dimensions in most of
the Hymenoptera, and is usually considerably
elevated above the level of the scutum. It is
in general of a triangular figure, and in many
species of this order, as well as in some Dip-
tera, is a marked character of the thorax being
often armed with spines. The post-scutellum
is not developed externally, but its position is
indicated by an elevated ridge, which is ex-
tended forwards on each side from the hinder
part of the scutellum very nearly to the base of
the anterior pair of wings, as in the Diptera
and Lepidoptera, and indicates the boundary of
the segment. It forms the meso-phragnia, and
as Mr. Macleay has remarked in Polities, is
connected with the scutum only at the sides,
being deficient in the middle line. The pec-
toral surface of this segment, the mesa-sternum,
is larger in Ichneumon Atropos (Jig. 390)
than in many other species. In form it is
nearly quadrate (3 g). It covers the whole
tinder surface of the segment, and is divided
fey a deep fissure into two halves. At its ante-
rior margin it is united by an indistinct suture
to a thin plate, the episternum, (3/,) that covers
the front of this part of the segment, and is
almost hidden behind the pro-thoracic legs, and
it has sometimes been considered as forming
part of that segment. Its lateral portion passes
upwards posteriorly to the collar of the pro-
thorax, and forms a process that projects be-
neath the anterior pair of wings, and above the
epimcron, (3 //,) which is the chief portion of
the side of this segment. At its inferior margin
this piece is united by an indistinct suture to
the sternum, at its anterior to the episternum,.

and at its posterior it is articulated \vrtl*
the coxa of one of the middle pair of legs-.

Fig. 390.

* OP. ck, P. m

h Aiinalcs de Sciences Naturales.

1831.

Lateral view of thorax of Ichneumon Atropos.

2 g, episternum j 2 h, epimeron and scutellunj*
of pro-thorax ; meso-thorax ^36, scutum ; 3 c,
scutellum ; 4 d, frenum ; * *, stigma ; 3 h, epi-
meron ; 3 g, sternum ; 3 f, episternum \ 5, scu-
tellum ; 4 b, scutum of ineta-thorax j t> to 14,,
segments of the abdomen.

The next segment, the meta-thorax, is an exceed-
ingly interesting portion of the body, owing tc*
the varied extent to which it is developed in-
the different Orders of Insects ; and on account
more particularly of the question that has been?
started, as to whether this portion of the thorax
in Hymenoptera is formed entirely by the
fourth segment of the larva, or whether a por-
tion of the fifth also enters into the composition,
of its posterior part, as believed by Audouir*
and Latreille. According t€> Mr. Macleay, the
•first piece of its dorsal surface or meta-notumy
the prfs-scuturn, is very distinct in Politics,.
while the scutum is concealed within the tho-
rax, being developed inwards to form a.
phragma, only a part of it being visible la-
terally,, but which, as usual, is connected with
the posterior pair of wings-, a circumstance that
invariably characterises the scutum in all in-
sects. In Ichneumon Atropos,. the prte-scutum
exists immediately behind the scutellum of the
meta-thorax, and covers part of the scutum?
(4 b,) which, although much encroached upon
in the median line by the developement back-
wards of this part and the scutellum of the
preceding segments,, is a distinct region on each
side of the meta-notum, and gives origin to the
posterior pair of wings. This sufficiently iden-
tifies the part as the proper scutum r otherwise
it might be mistaken for the prae-scutum of
Polistes, which is considerably more developed
than in Ichneumon Atropos. But the greater
part of the scutum is developed inwards, and
forms a deep cleft or incision, that divides the
segment into two parts transversely, the poste-

INSECTA.

921

rior portion of which, according to Mr. Ma-
cleay, is the proper scutellum (5) enormously
enlarged, while Audouin regards it as being
the dorsal surface of the fifth segment of the
larva, so that, if the latter opinion be correct,
the thorax of Hymenoptera must be composed
of four instead of three segments. We must
confess that at first we were inclined to Au-
douin's opinion, more especially on account of
what we shall presently find in Lepidoptera,
in which the fifth segment, in its atrophied con-
dition, is as much connected with the thorax as
with the abdomen. On further examination,
however, we are satisfied that that portion of the
meta-thorax which is posterior to the incisure
belongs to the third segment of the thorax ; but
we differ from Macleay in regarding it rather
as the scutellum and post-scutel!um united,
than as the scutellum alone. Its proper boun-
dary is marked on each side of the segment by
an elevated ridge or fraenum, (4 d,} which is
extended across the incisure from a little behind
the insertion of the wings, — where it is conti-
nuous with a ridge of the meta-notum, — as far
as the posterior margin of the acetabulum for
the insertion of the coxa of the leg. The post-
scutellum, therefore, may be regarded as having
coalesced with the scutellum, and assisted in the
enlargement of that part. It is distinct, but of
small size in Polistes, and is connected at its
upper part with a short ligament, or J'uniculus,
that is attached to the anterior margin of the
sixth segment (6), the first segment of the ab-
domen, which it assists to support. But we
have yet to trace the fifth segment of the larva,
which at first appears to be entirely lost. On
carefully separating or removing the meta-tho-
racic coxae of Ichneumon Atrvpos, we find a
very short plate, reduced almost to a ligament,
but still distinct as the remains of a separate
segment. It is the connecting medium be-
tween the under surface of the thorax and ab-
domen. We regard it as the remains of the
ventral plate of the fifth segment, of which the
upper or dorsal plate has entirely disappeared,
or exists perhaps in an altered form, as the fu-
niculus just alluded to. We are strengthened
in this opinion by an examination of several
species of Ichnettmonuhe, although in the gene-
rality of Hymenoptera the fifth segment ap-
pears to have coalesced with the sixth, to form
the petiole or peduncle of the abdomen. The
meta-sternum is formed of the same parts as in
the preceding segments. The paraptera are
situated immediately beneath the posterior
wings, in the triangular space bounded in
front by the epimeron of the preceding seg-
ment, and above and behind by the incisure
and frsenum, ( 4 d,) that connect the scutellum
with the scutum. The episternum is concealed
by the preceding segments, and the sternum is
reduced to a small triangular piece, situated be-
tween the coxae. The epimeron (4 h) is large,
to give attachment to the large coxae, but the
trochanlin does not exist as a piece distinct
from the coxa (/), with which it appears to
have become united. The meta-thoracic or
second pair of spiracles (**') are situated in the
anterior lateral parts of the scutellum. The

situation of the spiracles has sometimes been
considered as indicatory of the different seg-
ments, but, as remarked by Mr. Macleay, these
parts are unsafe guides, since they exist in
certain segments in some species, but not in
others, and their situation is often changed
during the metamorphoses from the larva to
the perfect state. We have seen that the meta-
thoracic spiracles of the larva are placed at the
most posterior part of the fourth segment, (fg.
356,) but in the perfect insect, as we now find,
this is not the case. If the situation of these
parts were alike in the two states of the insect,
there would be no difficulty in identifying the
segments of the imago with those of the larva.
Wre believe, however, that the true thorax is
formed of the second, third, and fourth seg-
ments in all insects, and that the fifth segment,
always greatly reduced in size, and sometimes,
as in this order, almost entirely atrophied, is
not in reality a part of the true thorax, but is
sometimes connected more or less with that
region, or with the abdomen, being intermediate
between the two. Hence we have ventured to
designate it the thoracic o-abdominal segment.

The number of segments in the abdomen of
perfect Hymenoptera appears on a cursory ex-
amination to vary considerably ; those in which
the abdomen is supported on a pedicle or foot-
stalk having fewer than others in which the
abdomen is of the same width as the thorax,
and the sting or borer of the female is not con-
cealed, as in Sirex juvencus. This insect on a
cursory inspection seems to have nine segments
in the abdomen, besides a very large terminal
joint, more than twice as large as any of the
others, which is pointed at its extremity, and
on the under surface of which is situated the
anal aperture. In reality, however, there are
but nine segments in this most developed form,
of abdomen, the tenth being only a large meta-
thoracic post-scutellum, which is extended
over the base of the abdomen, while the thir-
teenth and fourteenth segments of the larva.,
instead of becoming atrophied, as is usually
the case in other insects, during the metamor-
phoses, have coalesced and become enormously
enlarged in order to afford sufficient space for
the muscles required for the employment of
the strong terebra or borer with which the
insect penetrates the solid timber of living trees
to deposit her eggs. In the Tentknedtnidte, a»
in Ailantiis scrophularia , there are nine dis-
tinct segments besides the post-scutellum, and
this is probably the case in Athulia centifolite,
although we can discover but eight distinct
ones in that species. Wre suspect that the last
three segments in this insect become united to
form the parts connected with the female organs.
In the males there is the same number of seg-
ments as in the females. This is also the case
in Ichneumon Atropos (fig. 390), in which there
are nine distinct segments to the abdomen
besides the minute plate at the base of the
sixth, the remains of the thoracico-abdominal
segment before noticed. In the wasp, hornet,
and bee, only six segments are at first evident
in the abdomen, which arises from the circum-
stance that the anal segments, which form past

922

INSECTA.

of the organs of generation, are retractile within
the abdomen. The sixth segment is concealed,
and the seventh and eighth segments, particu-
larly the latter, which is greatly enlarged, form
the chief portion of the abdomen. In the
common honey-bee there appear at first to be
but five segments ; but one segment, the sixth,
which forms the base of the abdomen, is almost
concealed, and the others constitute the sting
and retractile organs of generation. In the
male or drone two segments are lost in the
termination of the male organs of generation.
Thus, then, the actual number of the segments
is the same in all Hymenoptera, the apparent
difference being occasioned by the retraction of
one or more segments within those which pre-
cede them. To so great an extent is this car-
ried in some species, as in the Chrysidida, that
the abdomen at first sight appears to be formed
of only four segments, the margin of the posterior
being armed with several spines. But even in
this family the number of segments is exactly
the same as in the Ichneumon above noticed,
in which all the segments are apparent. The
five last segments are retractile within the
abdomen, and when extended form a long
jointed tube, which is employed by the insect
for the purposes of oviposition. Thus then
the ovipositor of the Tubulifera, the sheath of
the sting in the Aculeata, and that of the terebra
or borer in the Terebrantia, are all derived
from the terminal segments of the body. But
we have already seen that in the hymenopterous
larva there is an additional segment to the
body, which from the existence of an appa-
rently additional organ in the perfect insect,
may reasonably be supposed to be especially
connected with the developement of that part.
On examination, however, it is discovered that
it is not from the fourteenth or terminal seg-
ment that the ovipositor, or sting, is entirely
derived, but from at least the two last segments,
the sheath being developed from elongated
portions of the thirteenth or penultimate seg-
ment, while the fourteenth forms only a short
valve at its base, like the extremity of the
abdomen in Sirex. From these circumstances
it is evident that the defensive organs of the
aculeate Hymenoptera are simply developments
of certain parts only of the sides of the abdominal
segments, while the tubulated joints of the ovi-
positor of the Chrysidida, with which there are
many analogies among the Lepidoptera, are the
entire segments. It is evident also that al-
though the fourteenth segment is certainly con-
nected with the sting or borer, it does not
become its chief part, the sheath of the organ
being always formed by parts of the thirteenth
and sometimes also of the twelfth segment, so
that these organs are simply developements of
parts which already exist in all insects. The
analogues of the ovipositor are found in the
Panorpida among the Neuroptera, and in the
Bombyad<£ among the Lepidoptera; while
those of the other forms of the same part, the
terebra and sting, exist in the exserted oviposi-
tors of the female Gryllid* in the Orthoptera,
and in the prehensile ones of some of the
Arciiida and other species, in almost every

instance the parts being derived from similar
segments.

In Lepidoptera the size of the three segments
of the thorax is more unequal than in Hymen-
optera. The prothorax is reduced to a very thin
plate or ring, more especially on its upper sur-
face or pronotum. On the prosternal surface
the primary parts, although greatly reduced in
size, are still distinguishable. The prostemurn
is a small square piece, which is articulated in
front by suture with a part of the anterior of
the basal joint of the first pair of legs, and
which we are inclined to regard as the tro~
chantinus (Jig- 392, 2 /c). Immediately above
this is a short semicircular piece, which is
perhaps the analogue of the epimeron, and
which is united by suture to a large broad
lunated piece, that forms the greater part of
the lateral surface of the prothorax, and is con-
tinuous with the narrow ring on the upper sur-
face (Jigs. 391 , 392, 2). The meso-notum is enor-
mously developed. The pr&scut um (Jig. 391)

Fig. 391.

•J3

Dorsal surface of Sphinx ligustri.

is hidden within the segment and forms the pro-
phragma, the anterior boundary of the segment.
Laterally it is extended on each side beneath
the scutum as far as the anterior boundary of
the wings, where it is developed on each side

INSECTA.

923

into a little inflated eminence, which we regard
as simply an extended portion of the prsescu-
tum unto which the parapteron is attached (3 e).
The scutum (3 6) forms a broad convex plate,
marked in the middle line by a raphe. It
extends from immediately behind the narrow
ring of the pronotum on each side to the in-
sertion of the anterior pair of wings, and
from thence backwards to a point opposite to
the margin of the posterior pair, thus forming
the greater portion of the proper thorax of the
insect. It gives attachment on its internal
surface to some of the most powerful muscles
of the wings, and consequently requires to be
more developed than any other part of the
thorax. It is separated by a deep triangular
suture from the scutellum of the mesothorax
(3 c), which as in Hymenoptera is a large and
important part. It forms the lozenge-shaped
posterior part of the mesothorax, and if care-
fully examined its angles are seen to pass under
the sides of the scutum, by the enlargement of
which it has been carried backwards. The
post-scutellum (3 d} has almost disappeared ; a
portion only of it is seen on each side at the
base of the anterior pair of wings, bounded by
an elevated margin, which extends outwards to
join a frcenum that is connected with the
posterior margin of the anterior pair of wings.
Besides these parts, which form the mesonotum,
there are also two broad moveable plates, the
paruptera (3 e}, that cover the base of the
anterior pair of wings. They are called by
Kirby and Spence putagia, or tippets, and are
loosely attached by a part of their concave sur-
face to the little eminences which we have
before noticed at the sides of the praescutum.
They are broad arched plates, which in form
resemble scapulae, and extend from the anterior
part of the scutum, the sides of which they
entirely cover as well as the insertion of the
first pair of wings. They are always covered
with long hairs, and are more developed in
Lepidoptera than in any other order. In
Coleoptera we saw them placed beneath the
wings on the anterior part of the sides of the
mesothorax. They were then unimportant
organs ; in Hymenoptera they were removed to
a position above the wing, but in this order they
have arrived at their maximum of development,
and appear to be of great importance to the
insect. The meso-sternum in Lepidoptera is
a part of very difficult examination, and we
are not confident that we have rightly made
out the analogies of its different parts with
those in other insects. The meso-sternum is
greatly reduced in size, while the base of each
kg is considerably enlarged. It appears to be
formed by an union of the trochantinus
(fig. 392, 3 A-), and of the coxa (/), these
parts in each limb appearing to be united, and
distinguished laterally by a very marked suture.
The base of the limbs thus occupies the greater
part of the meso-sternal region. The part
which we thus regard as the trochantinus is
articulated in front with the sternum (3 g), and
the coxa with the epimeron (3 A). The sternum
extends upwards on each side of the segment

Fig. 392.

Lateral surface of Sphinx ligustri.

as far as the upper portion of the epimeron, a
little below the insertion of the wings. It is
marked transversely by a depression which has
the appearance of a suture. At its anterior
margin, on the front of the meso-sternum there
is a very distinct plate which is united to it by
suture, and which appears to be the proper
episternal piece (3/). The spiracle or meso-
thoracic stigma is situated in a little fossa im-
mediately beneath the patagia on each side
before the anterior pair of wings, and com-
municates with the tracheae between the pro-
and meso-thoracic segments. The metathorax,
which bears the posterior pair of wings, is con-
siderably reduced in size by the developement
backwards of the scutellum of the meso-thorax,
which encroaches upon this segment poste-
riorly, as the scutum anteriorly does upon the
prothorax, but not to so great an extent. The
preescutum, as in the preceding segment, is
concealed within the thorax, being developed
inwards to assist with the post-scutellum of the
preceding segment in forming the meso-
phragma, while only a portion of the scutum is
visible on each side of the scutellum of the
meso-thorax (4 6), where it forms a triangular

924

INSECTA.

space, from the sides of which originate the
second pair of wings (*). It is bounded pos-
teriorly by a short thick ridge, the remains of
the scutellum (4 r), the extremities of which
pass outwards and are connected with the base
of the wings. The post-scute Hum (4 d) is
also a very short fold, that forms the most
posterior part of the true thorax. It is de-
veloped inwards and becomes continuous with
the remains of the upper portion of the fifth
or thoracico-abdominal segment (5). At each
side it is connected with the lateral portions of
the scutellum, and with it is connected to the
base of the posterior wings, and also with a
membrane or fraenum (5*) that passes from
the base of the posterior wings to the posterior
margin of the thoracico-abdominal segment,
thus clearly indicating the relation which this
segment bears to the last segment of the thorax.
The metaphragma or septum that exists between
the thorax and abdomen is formed during the
metamorphoses by a constriction in the middle
of the fifth segment, and as the changes pro-
ceed, a portion of the fourth segment, the post-
scutellum, is included in the fold or constriction,
and assists to form the metaphragma, so that
the fifth segment, at least in Lepidoptera, is
common both to the thorax and abdomen, and
cannot properly be said to belong more espe-
cially to one than to the other. Only a short
portion of the fifth segment exists on the dorsal
surface of the abdomen, posterior to the thorax,
while the inferior portion, which was more
reduced in extent during the changes than the
upper, is reduced to a very short piece, which
has entirely coalesced with the under surface of
the sixth segment, the first true segment of the
abdomen. In the meta-sternal surface there
are the same parts developed as in the meso-
sternal, the arrangement of all the parts being
precisely similar to those of the meso-thorax.
The trochantinus (4 /c) is united with the
coxa (/), from which it is distinguished, as in
the limbs of the preceding segments, by a
lateral suture. The first is articulated ante-
riorly with the sternum (4 g), and the second
posteriorly with the epimeron (4 h). The
second or meta-thoracic spiracle is situated in
a deep cavity behind the wings.

The abdomen in Lepidoptera consists of nine
distinct segments, or the remnants of that num-
ber of the larva if we include the segment which
we have thus seen is connected with the thorax.
We prefer, however, to consider the fifth as a
distinct segment, although a portion of it covers
the base of the abdomen. Each segment is
formed, as in other insects, of two arches, a su-
perior and an inferior one. The superior one is
a strong corneous plate, and is equal to nearly a
complete semicircle. The inferior plate is similar
in its form, but does not include so large a
portion of an arch, and is not so completely
solidified. The lateral margins of the inferior
arches are nearly straight, but those of the
superior ones are emarginated or notched, each
notch or incisure being near the middle of the
edge. It is occupied by an oval corneous ringf,
the stigma or spiracle which exists in the soft

membrane or conjunctiva that connects the
margins of the superior and inferior arches of
the segments. A similar membrane connects
the different segments together longitudinally
in such a manner that the anterior margin of
one segment is drawn beneath the posterior of
the one that immediately precedes it. By this
arrangement of the parts of the segments the
abdomen can be elongated or shortened at the
will of the insect, and expanded or contracted
during respiration, which takes place in the
abdominal as well as in the thoracic region.
There are nine stigmata or spiracles on each
side of the body. Two of these we have seen
are situated in the thorax, and the remaining
ones in the abdomen, from the sixth to the
twelfth segment; but the twelfth is apparently
closed, and probably does not take part in the
function of respiration, which is carried on
chiefly through the thoracic spiracles. It is
worthy of note also that there appears to be a
change in the situation of one of the spiracles
during the transformation of the larva and pupa
state. In the larva a spiracle exists in the fifth
segment, but this does not seem to be the case
in the perfect insect, in which the spiracle is
removed forward to the base of the wing in the
fourth, a circumstance which is highly interesting
from the fact that the wings are directly con-
nected with the organs and function of respira-
tion.

We will not enter further upon an examina-
tion of the thorax and abdomen in the different
orders, sufficient illustrations having been given
of the parts of which they are composed, and
of the manner in which they are developed
from the almost uniform body of the larva.

3. Organs of locomotion. — The wings, the
organs of flight in Insects, differ from those of
Birds in being supernumerary parts adapted
especially for aerial motion, as the legs, the
proper organs of progression, are for terres-
trial. The wings of Birds are simply mo-
difications of the anterior pair of extremi-
ties, which are employed in most other Ver-
tebrata either as organs of prehension or of
terrestrial or aquatic locomotion, and form parts
of the normal type of the skeleton.* But
the wings of Insects have no more analogy
with the legs, the proper organs of locomotion,
in the invertebrated than m the vertebrated
classes. They are derived entirely from the
respiratory structures, and have sometimes been
aptly designated aerial gills. They are ex-
panded portions of the common tegument of
the sides of the meso- and meta -thorax, occa-
sioned by the enlargement and extension of
numerous trachese and the accompanying pas-
sages for the circulatory fluids, and their motions
are intimately connected with the function of
respiration. These tracheae ramify throughout
every part of the wing, and immediately after
the assumption by the insect of the imago state
become solidified like the rest of the skeleton.
They are hollow for the reception of air like
the proper respiratory organs within the body,

* See the Article AVES.

INSECTA.

925

They afford strength and lightness to the wings,
with which they are in direct communication
like the bones in the wings of birds, although
the organs themselves in these different classes
are not analogous. Dr. Leach formerly desig-
nated these solidified tracheae in the wings of
insects Pterigostia, or wing bones, a name
that seems appropriate, both on account of
its convenience and as being indicatory of their
principal function, although it has sometimes
been objected to as incorrect on account of
their forming part of the respiratory system.
But it may be remarked that the true bones in
the wings of birds also communicate with the
respiratory organs, and perform functions simi-
lar to these in insects, while the interesting fact
noticed by Odier, that in their solidified con-
dition they are composed of the same kind of
earthy matter as that which enters into the
composition of other parts of the skeleton, is
sufficient to warrant us in retaining the designa-
tion. There appears to be no part of the body
in vertebrata analogous to the wings of insects,
except, perhaps, in the single instance of one
of the Saurian reptiles, Draco volans, in which
a pair of supernumerary organs to assist in
locomotion are developed from the sides of the
body, and which are formed by the ribs,
directed horizontally outwards and covered only
by the skin. We have thus in appearance the
remains in one class of the vertebrata of a con-
dition which is permanent in another class in
the invertebrata, which resemble them in their
general form and metamorphoses. In every
instance, then, the wings of an insect, like
these appendages of the thorax in the reptile,
are perfectly distinct in their origin from the
proper organs of locomotion ; they have their
normal condition in the lower invertebrata in
the superior branchial tufts of the Annelides,
and, consequently, are not more analogous to
the wing of the Bat, as they have recently been
supposed,* than to that of the Bird. We have
already seen that the full developement of the
wings takes place at the last change of the
insect, but it is commenced in the earlier
periods of the larva state, in which, with Oken
and Carus, we have detected these organs in
their most rudimentary condition. They are
distinctly seen on the second or third day after
the insect has assumed its last larva covering,
before changing to the pupa. They are then
scarcely so large as the head of a moderate
sized pin, and appear like newly-formed folded
portions of delicate tegument, extensively sup-
plied with ramifications of minute air-vessels,
derived directly from the principal tracheae.
They are at that time situated immediately
beneath the external covering, at the inferior
part of the sides of the meso- and meta-thoracic
segments, and continue to increase in size
during the growth of the larva. When the
insect has discontinued to feed, about a day
before changing into the pupa state, and the
new skin of the future pupa is nearly completed
beneath that of the larva, these rudiments of
the wings have become so much enlarged that

» Mod. Clas. Ins. vol. i. p. 11.

their existence is distinctly indicated by the
swollen appearance of the segments. It is at
this period of the larva state that they were
formerly discovered by Swammerdam.* At
the moment of fissuring the skin of the larva,
they are suddenly somewhat enlarged, and
when the skin has been cast off, and the delicate
parts of the newly exposed naked pupa are
beginning to be agglutinated together and folded
upon each other previously to becoming solidi-
fied to form the strong pupa case, they again
acquire a considerable increase of size, owing
to the extension and enlargement of the tracheal
vessels within them, together with a corres-
ponding increase in the quantity of the fluids
in the circulatory canals, by which they are
every where accompanied. The wings are then
expanded so as to cover the whole under-sur-
face of the thorax and limbs, and when the
insect subsequently bursts from the pupa case
and is assuming the perfect state, they are
again suddenly enlarged, and acquire their full
expansion through the recurrence of similar
phenomena.

It is thus evident that the wings are formed
from extensive ramifications of vessels inclosed
between two membranes, which are continuous
with, and are expanded portions of, the com-
mon tegument. In many instances, as in
Neuroptera, they are perfectly naked, or are
covered only with a few scattered hairs, as in
Hymenoptera. But in others they are densely
covered with peculiar cuticular developments in
the form of flattened scales, closely imbricated
upon each other, and inserted each by a little
footstalk or quill into little spaces in the exter-
nal membrane.f In other instances, as in the
Coleoptera, the anterior pair become solidified
and adapted to a new function, but are then
entirely useless as organs of flight. They serve
as covers to protect the posterior pair, which,
in a state of rest, are carefully folded beneath
them ; and when these are entirely absent, as
in some of the Tenebrionida, the anterior pair
become united together and form a strong
covering for the abdomen. Now we have seen
that the solidification of the tracheae alone
affords sufficient strength to the membranous
wings, which are always employed as organs
of flight, and that the earthy matter by which
they are consolidated is similar to that which is
the means of consolidating other parts of the
dermo-skeleton. It is by the deposition of a
greater quantity of the same kind of earthy
matter, not alone in the tracheae, but throughout
the whole substance of the wings, that the
anterior pair in Coleoptera are rendered entirely
useless, by their rigidity, as organs of flight,
and at the same time are made to assume a
new form and office, and become the means of
protecting the posterior pair, in those insects
whose habits might otherwise expose these
necessarily light and delicate organs to occa-
sional injury. This modification of structure,
then, in the form of elytra, consists simply in
the solidification, or, if we may venture so to

* Biblia Natura, Tab. xxxv. fig. II. e.

t Dr. Roget's Bridgewater Treatise, vol. i. p. 354.

926

INSECTA.

call it, ossification of the entire organs, and
not in any difference in their normal condition.
In every instance the anterior pair of wings, or
elytra, like the posterior pair, are formed of
numerous tracheae, accompanied by circulatory
canals extensively ramifying throughout their
whole structure, as may be well seen in the
imperfectly solidified wings of Orthoptera and
Ilemiptera, and in the perfectly formed ones of
many of the Coleoptera, although it has some-
times been supposed that the elytra are entirely
destitute of these structures.* Excepting in a
few instances, as in the Strepsiptera,f the elytra
are almost entirely motionless during flight, and
are either simply elevated or directed horizon-
tally in order that they may not impede the
motions of the true wings. Thus the number
and condition of the parts employed in flight
are seen to vary in different insects. In Co-
leoptera the posterior wings alone are actively
employed, in Neuroptera and Hymenoptera
both the anterior and posterior, but in Hymen-
optera the latter are smaller and less important
than the former, while in Diptera the posterior
are reduced to mere appendages of the atrophied
meta-thorax, and the office of flight devolves
entirely upon the anterior pair, which are the
only ones developed for such purpose. On the
other hand, in some species, instead of a reduc-
tion in the number of these parts, there is an
evident tendency to repetition, as is beautifully
shown in the existence of two circular mem-
branous appendages or winglets (alula) deve-
loped at the inner angles of the elytra, and
continuous with the delicate membrane that
lines the under surface in the great Hydrous
and the Dyticida. Similar appendages are
observed in the posterior wings of some Lepi-
doptera and Hymenoptera, and in the proper
wings of some Diptera. The non-developement
of the posterior wings in Diptera evidently
seems to be the natural result of the excessive
developement of the meso-thoracic segment,
which bears the proper wings, the analogues of
the anterior pair in Hymenoptera, and the con-
sequent atrophied condition of the adjoining
meta-thoracic segment, from which a posterior
pair ought to have been developed. But that
all insects, even the Diptera, have primarily
the same number of these organs, is exemplified
in this order in the existence of a pair of
appendages to the meta-thorax, in the form of
little club-shaped bodies denominated halteres
or poisers, and which exist modified in form
in every Dipterous insect. In the common
gnat they are simple footstalks surmounted by
a round knob, attached one on each side of the
atrophied meta-thorax. This is their form in the
house-fly and many other genera. That these are
the proper representatives of the posterior pair
of wings is now the opinion of the most recent
observers, and is most decidedly confirmed by
the results of our own examinations. They
are generally more or less concealed beneath
the winglets, from which they are perfectly dis-
tinct, being always connected with the meta-

* Westwood, Text Book, p. 283.

t Dale in Curtis 's British Entomology, fol. 226.

thorax, while the winglets are attached to the
scutellum of the meso-thorax, and in some
instances, as in Tabanus bovinus, are continu-
ous with the margin of the meso-thoracic
wings.

The articulations of the wings are formed
upon the same principles as those of the legs,
but are more simple in their construction. Those
at the proximal extremity of the cubital tier-
vures, or pterigostia, are of a somewhat cotyloid
form to allow of free motion in several direc-
tions, and often, as in those at the base of the
elytra, are furnished with a long spine or process,
to which some of the powerful muscles are
attached. Those by which the wings are
folded beneath the elytra are imperfectly formed
ginglymoid joints in the nervures, and seldom
allow of motion in more than one direction.
In most Coleoptera, as in Scarabaidte, Hydro-
philidtf, &c. there is only one of these joints in
each wing, but in the Brachelt/tra, in which
the wings are closely packed beneath very short
covers, there are often so many as four in each
wing,* while in other species, as in the Bu-
prestidce, in which the wings are not folded
but are only of the length of the abdomen,
these joints are entirely absent. In every
instance the membranous portions of the wings
are either plaited longitudinally or folded trans-
versely when the wings are concealed beneath
the elytra.

In the rteuration, or distribution of the tra-
cheae in the wings, pterigostia, which by the
French entomologists are called nervitres, on a
casual inspection there appear to be many
remarkable variations. But when the wings
are attentively examined, it is found that there
is always a great uniformity in the distribution
of the principal nervures, and this is so precise
and regular in many orders that it has been
employed by some naturalists as strongly cha-
racterizing different groups. The irregularity
which at first is supposed to exist in the dis-
tribution of these nervures in some families
arises entirely from the greater or less relative
enlargement of the principal trunks or their
branches. The characters derived from these
parts were formerly employed by Frisch in
Germany and Harrisf in this country, but
have of late years been more particularly ap-
plied to the classification of Hymenoptera by
Jurine,} St. Fargeau, and Mr. Shuckard, the
first two of whom have founded their arrange-
ments of Hymenoptera upon characters de-
rived almost entirely from these structures,
each of which they have designated by a distinct
name. Mr. Shuckard, who has studied this
subject with much care, gives the following
description of the anterior wing in Hymenop-
tera^ " The contour of the wing is formed
by its anterior, apical, and posterior margins.

* Straus, Considerat., &c. p. 127.

t Exposition of English Insects, 4to. London,
1782.

J Nouvelle Methode de Classes les Hymenop-
teres et les Dipteres, par L. Jurine, torn. i. 4to.
Geneve, 1807.

§ Transactions of the Entomological Society of
London, vol. i. p. 209.

INSECTA.

927

The anterior margin is that portion which is
situated anteriorly upon its expansion in flight,
extending from its base to its distinctly visible
extremity of the costal nervure, a little beyond
the marginal cell; at its termination the apical
margin commences, and extends to the sinus
of the wing, which is the incision at the apex
of the posterior margin, which latter extends
from this sinus back to the base, and it is by
this margin that the upper and under wings
are connected in flight. The costal nervure is
the first longitudinal nervure of the wing
(fg. 393, «), and, as we have seen, extends

Fig. 393.

i

Wing of Hymenopterous insect {Shuckard).

a, costal nervure; d, post-costal; S, stigma;
e, exteruo medial ; f, anal ; g, transverso-medial ;
1, costal cell -, 2, medial ; 3, interno-medial ; 4,
anal ; h, radial nervure ; 5, marginal cell ; 6,
cubital nervure.

upon the anterior margin to just beyond the
extremity of the marginal cell. The second
longitudinal nervure is the post-costal (d); this
extends to the stigma (s), which is that thick-
ened point or spot upon the wing placed upon
its anterior margin at about two-thirds the dis-
tance of its base and extreme apex, and ap-
pears to me to be a dilatation of the costal
nervure. The third longitudinal nervure is the
externo-medial (e\ which proceeds in a direct
line nearly parallel with the preceding for a
little more than half the length of the post-
costal, or about one-third of the entire length
of the wing, and then leads off at an obtuse
angle to join the post-costal just before its
junction with the stigma. The anal (f) is the
fourth longitudinal nervure, which also extends
from the base to the sinus at the apical ex-
tremity of its posterior margin: a transverse
nervure unites the externo-medial and anal,
and which I purpose calling the transverso-
medial (g). These nervures, which I consider
the primary nervures of the wing, severally
inclose what have hitherto been called collec-
tively the basal or humeral cells, but to which
I purpose applying different names (derived
from the nervures which inclose them), that
they may be more readily distinguished from
•each other. The first, or that very narrow one
between the costal and post-costal nervures, is
the costal cell (1) ; the second is that placed
between the post-costal and externo-medial
nervures, and which I call the externo-medial
cell (2): that inclosed between the externo-
medial and anal nervures parallelly, and ter-
minated at its apex by the transverso-medial,
is the interno-medial cell (3); and the cell

seated between the anal nervure and the pos-
terior margin of the wing is the anal cell (4).

" From the interior margin of the stigma
arises the radial nervure (A), which makes a
curve and then joins the costal upon the mar-
gin of the wing : the lanceolate space thus in-
closed forms what is called the radial or mar-
ginal cell (5). The cubital nervure (6) is
nearly parallel with the radial and originates
from the externo-medial near its junction with
the post-costal ; this extends to the apical
margin of the wing just below its extreme
apex (6 i). The space thus inclosed is divided
by three transverse nervures, which I propose
calling the transverso-cubitals (m, m, m, m),
inclosing as many spaces forming so many
cubital or sub-marginal cells, a fourth being
formed in consequence of the nervure extend-
ing to and joining the apical margin (g}. The
third nervure, originating from the primaiy
nervures of the wing, is what I call the dis-
coidal nervure (/c), (it is from this that I anti-
cipate the chief results), and which, commenc-
ing at the transverso-medial, extends in a di-
rect line to the disc of the wing directly be-
tween the stigma and the sinus, when it makes
a sudden curve at a right angle backwards and
joins the anal nervure close to the sinus (/c).
From this discoidal nervure at the centre of its
apical return another springs, forming what I
call the sub-discoidal nervure (/), and which
here extends to the posterior margin of the
wing. From the cubital nervure two others
originate ; these are called the recurrent ner-
vures, the first of which always inosculates at
the angle of the discoidal nervure, and the
second just beyond the centre of the sub-
discoidal. By the reticulation of these four
nervures several cells are formed upon the disc
of the wing ; the first of these, which is in-
closed between the discoidal and anal nervures,
I call the first discoidal cell^lO). The second
is that placed between the externo-medial cubi-
tal, first recurrent, and discoidal nervures (11).
The third discoidal cell is that inclosed by the
second recurrent, sub-discoidal, discoidal, and
first recurrent nervures (12). The space in-
closed between the second recurrent, sub-dis-
coidal, and cubital nervures, and the pical mar-
gin of the wing, forms the first apical cell (13),
and there is a second only when the sub-dis-
coidal nervure extends to the apical margin,
by which and a portion of the discoidal cell
it is inclosed."

The distribution of the nervures in the wings
of the males of some of the Orthoptera affords
some curious peculiarities, by which the pteri-
gostia become instrumental in the production
of sounds. At the base of the superior pair
of wings in Acrida; at the inner angle of each
wing, is an oval or nearly circular space
(fig. 394, o), in which the membrane is more
transparent and free from ramifications of ner-
vures than in any other part of the wing.
These spaces have long been known to be con-
nected with the production of sound. The
membrane itself appears to be thinner than in
other places, and more tense, and the nervures
by which it is inclosed are thick and strong.

928

INSECTA.

Fig 394.

A, inferior surface of left wing of Acrida viti-
dissima.

B, upper surface of the right, and, C, under sur-
face of left wing of Acrida brachelytra, shewing
the tympanum a, and bow c, across which the file
6 acts.

b, the file magnified.

Until recently it has been supposed that these
were the only parts in the male Acrida con-
cerned in the production of sound, the me-
chanism of which has been explained by Bur-
meister* as consisting in a quick attrition of
the wings against each other during a forcible
expiration of air from the thoracic tracheae and
spiracles, which are situated beneath, and are
covered by the edges of the wings ; that the
air in rushing out of these spiracles is driven
against the tympani, which are thus occasioned
to vibrate and produce the sound. But this
ingenious explanation is not entirely correct;
the means employed do not appear sufficient to
explain the phenomenon, besides which a part
of the structure that is chiefly instrumental in
producing the sound has been overlooked. In
addition to the tympanum, and parts by which
it is inclosed, there is also another part which
has not until recently been described. It is a
strong, transversely elongated horny ridge,
situated immediately behind the tympanum,
near the base of the wing, and is most distinct
on the upper surface of the wing of the left
side. This part was first shown to us by the
late Mr. William Lord, in the wing of Acrida
viridivsima, in February 1838, but it had pre-

* Manual (trans! at.), p. 470.

viously been described by M. Goureau, in an1
elaborate paper on the Stridulation of Insects.*
When examined minutely, this ridge, which is
of the colour and appearance of tortoise-shell,
is found to be striated transversely, so as to
resemble a rasp or file. Goureau has called
it the bow ; a similar ridge or file exists on
the under surface of the right wing, but less
strongly notched, and is called by Goureau
the false bow. When the wings are rubbed
briskly together, these rasps or bows produce
a loud grating against some projecting or ele-
vated nervures on the borders of the wings, by
means of which the drum is made to vibrate
like any other tensely stretched membrane
when agitated, the intensity of the sounds pro-
duced depending entirely upon the rapidity
and force employed by the insect during the
attrition of the parts concerned, and being
entirely independent of any forcible expiration
of air from the thoracic spiracles, which is
thus seen to be unnecessary for the production
of the sound. That this is really the case is
proved by the fact that in Acrida brachelytra
(B, c), the wings are so exceedingly short and
narrow that they do not cover, nor are they even
near any part of the spiracles, so that the air in
passing out of these orifices cannot possibly be
driven against the tympanum. On the other hand
the tympanum in this species (Jig- 394, B, C)
is considerably larger than in others of the
same genus, and not only has its margins more
elevated, but has also a strong bar extended
across near its base (c), is itself more tense
and vibratory, and has a short, strong bar (</),
connected with the ring by which it is inclosed,
and also, at a right angle, with the origin of
the great marginal nervure of the wing. It is
remarkable that both in Acrida viridissima and
Acrida brachelytra, the tympanum in one wing
differs from that of the other in being less re-
gular in its form, much more opaque, and tra-
versed by several tracheae, a circumstance
which leads us still further to infer that the
sounds produced result from the vibrations of
one only of these organs, besides which the
proper tympani are not in corresponding wings
in these two insects. In the former, in which
the base of the left wing is covered by that of
the right, the proper tympanum is in the left
wing, while in the latter insect, in which the
right wing is covered by the left, the tympa-
num is in the left wing, which is remarkable in
being entirely deficient of the file or bow, but
which is largely developed on the under sur-
face of the left wing. The analogue of the
file in the right wing is evidently a strong por-
tion of the rim of the tympanum nearest to the
base of the wing. It is remarkable also that
in this species the whole surface of the right
wing, in which the tympanum is situated, is
more transparent and free from nervures than
the corresponding part of the left wing, so that
the whole surface of the wing may perhaps be
rendered sonorous. It is remarkable also that

* Annales de la Societe Entomologique de France,

1837, p. 31. Entomological Magazine, January*

1838, p. 89 et seq.

INSECTA.

929

in newly developed specimens, particularly in
Acric/a vtridissima, the teeth or markings on
the file are more distinct than in those which
have been a longer time in the perfect state, in
which the teeth appear as if partially oblite-
rated by use. The sounds, as remarked by
M. Gpureau, may be readily produced in the
dead insect by gently rubbing the bases of the
wings together, a further proof that the rushing
of air from the spiracles is totally unconnected
with their production. A similar structure
exists in the wings of Acrida grisea and others
of the same genus. In the Achetida the parts
for stridulation are somewhat differently con-
structed. The wing of the common house-
cricket, Achetu domestica, differs materially in
the two sexes. In the male (Jig. 395) the two

Fig. 395.

Fig. 396.

Wing of the male House- Cricket, Acheta dome&tica,
shewing thejile, b, and tympanum, a.

wings exactly resemble each other, and the
nervures are more irregularly disposed than in
the female, in which they are arranged either
longitudinally or diagonally with but very few
that run in a transverse direction. When the
wing of the male is attentively examined,
nearly one-half of its surface is found to be
adapted to perform the office of a tympanum.
This part is more transparent and elastic than
the other, and is crossed by many nervures in a
manner somewhat similar to the tympanum in
Acrida brachelytra. Besides these there is on
the under surface of each wing a large nervure,
which is curved and placed somewhat trans-
versely near the base of the wing, as in Acrida.
It is the file or bow, and is covered by a vast
number of minute, but freely elevated, semi-
circular teeth, which gradually decrease in size
as they approach the external angle of the
wing fjig. 396). The smallness of the teeth,
and the extent of surface over which they are
passed when the two wings are rubbed briskly
across each other, is probably the cause of the
very acute sounds produced by this insect. In
Gryllotalpa, which is said to produce a hoarse
croaking sound, the two wings exactly resem-

VOL. II.

The round file of Acheta domestica.

ble each other, as in Acheta. The nervures
are thick and strong, and there is no distinct
vibratory membrane, but on the under surface
of each wing are a vast number of minute
sharp-pointed teeth arranged closely together
along the middle of the nervures, not only
upon that one which is analogous to the file in
Acrida and Acheta, but also upon three others
which run in a parallel direction with it, as well
as on their transverse or connecting branches,
so that the whole of the nervures at the base
of each wing are covered with files, which,
when the two wings are rubbed across each
other, produce, owing to the shortness of the
nervures, a low grating sound. We do not at
first perceive the necessity for a stridulatory
apparatus on the under-surfaces of both wings,
if the sounds produced result simply from the
attrition of the wings against each other, and
the wings have always the same relative posi-
tion. But on close examination it is found
that, although in the Gryllida the right wing
either constantly overlaps the left or the left the
right, in the Achetida this is not the case, but
that sometimes one wing and sometimes the
other in the same insect is the supenor. With
regard to the acuteness of the sounds produced
by the house-cricket, it probably depends
much upon the length of the vibrating nervures
on the large tympanum, as well as the small-
ness of the teeth in the file, as the hoarse
sounds do, perhaps, upon the shortness of the
nervures in Gryllotalpa. In Locustida: the
stridulation is not connected with the structure
of the wings.

Besides these various parts for the produc-
tion of sounds, the wings of some insects are
furnished with others equally remarkable, but
designed fora different purpose. These con-
sist of certain little hooks and foldings on the
margins of the wings, by means of which in
some families the two pairs are united during
flight, in order that the motions of these organs
may be in perfect unison with each other. In
some genera, as in the Lepidoptera, the males
alone are provided with these booklets, as was
formerly noticed by Mr. Haworth* in Apatura
Iris, in which the wings of the male are con-
nected at their base by means of a strong elastic
spring, which arises from the base of the costal

* Lepidoptera Britannica, 8vo. Londini, 1803.
3 P

930

INSECTA.

nervura of the inferior wing, and is received
into a socket near the base of the main nervure
on the under side of the upper wing. This
apparatus for connecting the wings appears to
give additional strength to the insect, since it
exists only in those species which fly most
rapidly, and continue for a great length of time
on the wing. But in those insects in which
the body is very large in proportion to the
size of these organs, and which are necessitated
by their habits to be constantly abroad, and to
fly to a great distance, as is the case with the
Hymenoptera, the means of uniting the wings
is more perfect. It consists not of a single
booklet, as in Lepidoptera, but of a series of
very minute hooks of a somewhat spiral form
(Jig. 397), and arranged along a curved portion

Fig. 397.

A, inferior wing of Bombus terrestris ; a, the
costal nervure, on which are seated the hooks, b ;
(c, the winglet) ; B, the hooks in the working bee,
apis metttftca.

of the costal nervure, at the anterior superior
margin of the second pair of wings. These
hooks are described by Mr. Kirby,* and are
found in nearly all the Hymenoptera. They
are arranged in a slightly twisted or spiral
direction along the margin of the wing, so as
to resemble a screw, and when the wings are
expanded attach themselves to a little fold on
the posterior margin of the anterior wing, along
which they play very freely when the wings are

* Monographia Apum Angliae, vol. i. tab. 13,
fig. 19. Ipswich, 18U2.

in motion, slipping to and fro like the rings on
the rod of a window curtain. The form of
the hooks is very similar throughout the whole
order, each hook being twisted at its extremity
a little to one side and recurved. They are
always situated at the same part of the wing,
but vary in number in different genera, and
even in the sexes. In Urocerida, Slrex juven-
cus, they are few and scattered along the margin
of the wing, and this is also the case in Tri-
chiosoma, but we have found them far more
numerous in Ichneumon Atropos. In the
sterile fema?2 or worker of the common wasp,
Vespa vulgaris,\ve have found them very strong,
and about twenty in number, besides five stiff
spines which are not bent in the form of hooks.
In most instances, particularly in the Bombi,
the hooks are less numerous in the males than
in the females. Thus, in the male of Bombus
terrestris there are but eighteen in each wing
in the male, but twenty-five in the fertile
female. In the male of Bombus lapidarius
there are only eighteen in each wing, and there
is the same number in the worker or sterile
female, but there are twenty-three in each wing
of the fertile female. In Anthophora retusa there
are only twenty in the male, but twenty-two in
the female. In Osmia there are twelve in the
male and fifteen in the female. But the reverse
is the case in Anthidium manicatum, in which
there are thirty in the male, but only twenty-
five in the female. In Megachile there are
sixteen in the female, but in the cuckoo-bee,
Melecta punctata, there are thirteen hooks and
four imperfectly developed spines. In the
male of Eucera longicornis there are only
thirteen hooks, but in the female twenty-three,
while in the female Calioxys conica there are
only twelve. In the queen or fertile female of
the common hive-bee there are only seventeen
slender hooks, arranged at some distance apart,
and different in their appearance from those of
the common humble-bee. In the sterile female
or worker there are nineteen, but in the heavy
male, or drone, there are twenty-one. In the
male, as in the fertile female, of the hive-bee,
the hooks are placed further apart, and are more
slender than in the workers, besides which they
are differently shaped in the neuter, in which
each hook has also a little tooth near its apex.
On reviewing this difference in the number of
hooks in the two sexes, we are certainly con-
firmed in the opinion that it has some relation
to the comparative powers of flight of the
respective insects, and is not a sexual distinc-
tion. The great object of the hooks evidently
is to keep the wings steady during flight, in
order that they may act in unison, and thereby
enable the insect to continue much longer on
the wing with less muscular exertion, because,
when the two wings are made to act but as one,
the effort of flying becomes more concentrated,
and the wings strike the air with greater effect
than if they were separated or but imperfectly
connected. It is well known that the males of
the humble-bees, Bombi, are much feebler on
the wing than the fertile females, and it is the
same with the individuals of the genus Osrnia,

INSECTA.

931

and perhaps also with those of Anthophora, in
which, although the flight of the males is as
rapid as that of the females, we suspect that it
is not so long continued. But in Anthidium
manicatum the number of hooks is in corres-
pondence with the apparently greater power of
wing in the male, which pursues his partner
unceasingly, and darts down upon her with
great rapidity at the season of connubiality.
A similar remark is applicable to the male of
the hive-bee, which at the period of swarming
is exceedingly active, and constantly on the
wing in the open air, in search of the queen or
solitary female, who leaves the hive but for a
few hours on the first or second day after
swarming. Now we have seen that the number
of hooks in these males is greater than in the
females, and that their powers of flight are
also greater, and that in the Bombi the reverse
is the case with regard to both these circum-
stances. Consequently it is but fair to infer
that the number and strength of the hooks are
in direct relation to the powers of the insect.

We have before remarked that the different
forms and appendages of the body are invariably
the result, not of the introduction of new
elements into the composition of parts, but
of the greater or less extent to which those
primary parts are developed. There is a beau-
tiful illustration of this principle in the develop-
ment of the hdftiuli, which are only spinous
processes often observed on the wings of other
insects. In proof of this we need but examine
the wing of the common working-bee, in which
there are several of these spines arranged in
a line with the hamuli, and inserted in a similar
manner into the nervure of the wing upon which
the hooks are situated. In some instances the
transition of form from that of spines to hooks
is distinctly marked. Those which are most
distant from the proper hooks retain the perfect
form of spines, while those which are nearest
are bent in the same direction, but to a less
extent than the pre per hook, but sufficiently so
to mark very distinctly their proper analogy.

In Hemiptera, instead of being connected by
hooks as in Hymenoptera, the whole margin
of a portion of the anterior wing is hooked over
a corresponding recurved part of the posterior,
as formerly noticed by Chabrier* in the Penta-
tomidtf. In the Homoptera the wings are con-
nected in the same manner as in Hemiptera, as
noticed by Mr. Ashton-f in Membracis cornuta.
This is also the case in other Homoptera. Thus
in Tettigonia bifasciata there is a triangular
membranous process extending from the anterior
margin of the inferior wing, and which on its
distal border is furnished with four very dis-
tinct but exceedingly minute hooks, resembling
those of Hymenoptera. This process of the
posterior wing is curved a little upwards and
received into a fold of the posterior margin of
the anterior wing. There is a similar structure
in the wing of Cercopis sanguinolenta, with
this difference, that the hooks are very indis-

* Sur le Vol des Insectes.

t Proceedings of the Entomological Society of
London in Transactions, vol. ii. p. 20.

tinct, while the triangular process of the wing
is more pointed and hooked upwards. In
Tettigonia spumaria the structure is exactly
the same. In lassus viridis the triangular
process is shorter, but more extended along
the costal margin of the wing, and is furnished
with a great many very minute imperfectly de-
veloped hooks, which attach themselves to the
folded linear margin of the anterior wing.

The legs, the proper organs of locomotion,
are constantly six in number in every order of
insects, but are subject to much variety of form.
Each leg is composed of five distinct parts.
First, (Jig. 332 and 398,) the coxa (a) or basial

Legs of insects, from Bttrmeister, Curtis, and Hope.

joint, which is inserted into the acetabulum,
and connects the limb with the thorax. Of
this part the trochantin is believed to be an
appendage. Secondly, the trochanter, a
minute joint attached to the extremity of the
coxa. It is not lettered in our figure of the leg
(Jig. 332, 3, 4), but is placed between the
coxa and the third portion of the limb, the
femur (6), with which it is freely articulated.
The femur is the proper thigh of the insect, and
in general is of considerable size. It is con-
nected by ginglymoid articulation to the fourth
portion of the limb, the tibia (c), which is
usually a long slender joint, at the extremity of
which is articulated the fifth and last portion,
the tarsus (<f). This part is always composed of
several distinct joints, varying in number in
different insects from two to six. The more
common number is five. These are the pri-

3 P 2

932

INSECTA.

mary divisions of the leg, connected together
by distinct articulations, and in the most de-
veloped condition of the limb are almost in-
variably found in every insect. The articu-
lation of the coxa with the acetabulum is
either ginglymoid, as in the Lamellicornes and
many others, or cotyloid, as in most of the
Rhinchophora ; that between the coxa and
trochanter, and between the trochanter and
femur, is chiefly of the former kind, which
also invariably exists between the femur and
tibia, while the articulations of the different
joints of the tarsus with one another, and also
with the tibia, are almost invariably cotyloid,
as in Lucanus, except in the four posterior legs
of the Hydradephaga and other water insects,
in which they are usually ginglymoid, because
the tarsi of these insects being used chiefly for
one purpose, that of swimming, this form of
joint appears to be necessary to give greater
strength to the tarsus, which is employed to
strike the water almost wholly in one direction.

Although the number of joints in the tarsus
varies in different insects, it is very constant in
some families, which are also connected by
other circumstances. Thus in a large group of
the Coleoptera the tarsi are invariably com-
posed of five joints, besides a terminal claw,
and upon this character they have been formed
into one group, the Pentamera ; while in
another, the Heteromera, there are constantly
five joints in each tarsus of the pro and meso-
thoracic legs, but only four in each of the two
metathoracic. This tendency to the production
of the full number of joints is remarkably
shewn in many instances. Thus in a large
number of families, Psevdo-tetramera, in which
on a cursory examination there appear to be
only four joints in each tarsus, it is found on a
closer inspection that a fifth joint actually does
exist, in the form of a very minute articulation
(Jig. 398, A, 4), at the base of the terminal
joint in each tarsus. So again in another group,
Pseudu-trimera, in which there appear at first
to be only three joints in each, it is found that
there are actually four (B, 3), the additional
joint being, as in the preceding instances, de-
veloped at the base of the terminal one, but
more distinctly than in the Pseudo-tetramera.
This tendency to a reproduction of parts is
also shewn in the claws at the extremity of the
tarsi. In many Coleoptera, as in the Melolon-
thid<e (C), each claw is double; while in
others, as in Lucanus, in which the proper
claw is simple, and articulated to the terminal
joint of the tarsus, there is also an unguicula
or little claw, supported upon a distinct joint,
which is articulated separately from the proper
claw, with the last joint of the tarsus, in the
middle line below the larger one.

The variations that occur in the form of the
parts of the leg, as in other parts of the body,
are directly referable to the habits or necessi-
ties of the insect. Thus where the legs are
employed chiefly in running, as in the Ci-
cindelidae, Carabidte, Scuritidd', and HciJ-palidte,
they are usually long and slender, particularly
the tarsi and tibia? ; the coxae are very freely
articulated with the body, and the trochanters,

particularly those of the hinder pair of legs,
are remarkably large. But when, as in the
Gyrinid&f Dyticidae, and Hydrophilidte, they
are employed entirely in swimming, they are
long, as in running insects, and the tarsi of the
second and third pairs are flattened and broad
like oars, and their margins, apparently to in-
crease the breadth of their oar-like form in the
water, without the inconvenience of an actual
enlargement of the limbs, are densely clothed
with long stiff hairs (K). Besides this, the
posterior pair, on which the chief action of
swimming depends, are much longer than the
others, and the tarsi are ciliated to the very
articulation of the unguis. The extremity of
each tibia is also armed with one or more long
spines, which may assist the insect perhaps in
burrowing into the mud. When the legs are
employed simply in walking, and the motions
of the insect are slow, the legs are all of the
same length, and, as in the Chrysomelida, are
often covered on the under surface of the
tarsi with little hairy cushions, pulvilli. These
are generally present also in climbing insects.
In the common house-fly, and others of the
same genus, instead of hairy cushions the ter-
minal joint of each tarsus is furnished near
its extremity with two funnel-shaped mem-
branous suckers (E), by means of which the
insect is enabled to adhere to smooth surfaces,
and suspend itself in an inverted position.
Each of these is concave, and covered by a
membrane, and the manner in which the in-
sect attaches itself is by exhausting the air
beneath each sucker. The cushions are parti-
cularly large in those anomalous insects the
Streps iptera, in which they form a broad heart-
shaped surface to each joint of the tarsi (M).
They are also present, but in a less perfect
form, in some of the running insects, the Cicin-
delid<K and Carabute, as in Diorycke torta*
(MAc'L.), in which the joints of the anterior
tarsi are furnished with a little hairy cushion.
But in these families the tarsi of the anterior
legs of the males are always enlarged for the
same purpose as in the Dyticida, that of more
securely attaching themselves to the female.
This is also the case in Hydrous, in which the
terminal joints of the anterior tarsi (fig- 330, A)
are very much dilated. In the Dyticid/e
the first three joints of the anterior tarsi are
consolidated together, and form a broad cir-
cular disc, covered with many minute funnel-
shaped suckers, two or three of which are
much larger than the others; in some, as in
Hyderodes Shuckardi, HoFE,t a New-Holland
species (H), all the suckers are of nearly the
same size. They exist also in the first three
joints of the second pair of tarsi (I). A some-
what similar structure exists in the males of
some of the sand-wasps, Crabronida (F). It is
supposed to be designed for the same purpose
as in the DyticidoE. But in those insects it
consists of a broad and slightly convex dila-
tation of the anterior tibiae, and not of the

* Coleoptevist's Manual, Part ii. tab. 2.
4, d.

t Op. cit. pi. 3, fig. 5. a. b.

fig.

INSECTA.

933

tarsi, as in the latter instances.* Those insects
which support themselves upon the surface of
water, as the common gnat, have the under
surface of each tarsus covered with rows of
fine hairs, which repel the water, and support
the insect upon the surface. If the under sur-
face of the tarsi be wetted with spirits of wine,
the insect can no longer support itself upon
the surface, but immediately sinks down.f
When the legs are employed in jumping, as in
Hulticti, the destructive flea-beetle of the
turnip, and the Gryllida and Locustidtf, the
posterior pair, upon which devolves the greatest
effort, as in the swimming insects, are con-
siderably larger than the others ; the thighs in
particular are enlarged and lengthened, to
allow room for the insertion of the muscles.
But when the legs are employed in digging or
burrowing, it is the anterior pair that become
the most important, as in the mole-cricket,
Gryllotalpa(G). In that insect the coxa (a)
is of an enormous size, and the trochariter at-
tached to its inferior margin consists of two
distinct articulations, one of which projects in
a lobulated form, and probably is useful in
assisting to remove the earth during the ope-
rations of the insect. The femur (6) is short
and broad, and is articulated both to the coxa
and trochanter, and thus derives additional
strength from its more secure connexion with
the base of the limb ; while the tibia (c), which
is the part immediately employed in burrow-
ing, is also short, and divided at its extremity
into four strong curved spines, directed out-
wards, and forming as it were a broad hand,
like the claw of the mole, for digging into and
rapidly removing the earth in its burrow. The
tarsus (d), which appears to be almost useless
in these subterranean labours, consists of three
short articulations, which are attached to the
external surface of the tibia. A similar con-
formation of the tibia exists in other burrowing
insects, since it is always this part of the
limb that is employed in digging, and not the
tarsus, which is used only in scraping or
scratching away loose soil, as by the oil-beetles,
Me lot, and the sand-wasps. Thus in the
Scarab&ida and Geotrupida the anterior
tarsi are broad and dentated laterally, and the
posterior ones are armed with strong spines.
In some genera, as in the Coprides and
Onthophagi, the extremities are not only
strongly spined, but are also broad and club-
shaped, to assist them in penetrating into the
loose excrement beneath which they are ac-
customed to burrow.

There are circumstances connected with the
organs of locomotion in insects of considerable
interest, and which cannot be passed over.
These are the aberrations of form which they
undergo as a consequence of incomplete de-
velopment, and the occasional existence of
supernumerary limbs, the result of an opposite
tendency in the development of the germ.
We have already alluded to the changes of
form occasioned by the former of these circum-

* Degeer Memoires, t. ii. p. 810, pi. 28.
t Dr. Roget's Bridgewater Treatise, vol. i.

p. 334.

stances, and we have now to notice the not less
remarkable occurrence of the latter. Although
every part of the body is subject more or less
to these occurrences, the supernumerary parts
are almost always antennae or legs. We do
not remember a single instance of a supernu-
merary wing, or elytron, or organ of mandu-
cation, although the whole of these parts are
occasionally subjected to an aberration of form
in consequence of imperfect development.
Many instances of this kind are given by Dr.
Herrmann Asmuss,* who has collected a mul-
titude of facts connected with this interesting
subject, from which it appears that abnormal
forms are more frequent in the antennae and
legs than in other parts of the body. Only
one instance is given of abnormal form of the
mandible from arrested development, but
several of the antennae and legs. But the
most frequent abnormal condition is found in
the existence of supernumerary parts. Of
these he has given two instances in which the
antenna on one side of the head was double.
These occurred in one of the Elateridte, Athous
hirtusj\ and Carabus auratus,\ and one instance
also in which it was trifurcated, in Helops
carulens.§ But it is remarkable that the most
frequent occurrence of supernumerary parts is
of the legs. Of these Asmuss has collected
eight examples, and it is remarkable that in
six of them the parts on one side are treble.
Of the two instances in which the parts were
double the first occurred in Agriotes obscurus,\\
in which there were two perfect prothoracic
legs on the right side of the body, connected
with the sternum by two distinct coxa?. In
the other instance, which occurred in Tele-
phorus Jmcus^ there were two meso-thoracic
legs on the left side, connected together, and
attached by a single coxa to the sternum.
To these we may add a third instance, which
occurred in Chrysomela hcemoptera, captured
by Mr. Curtis, and described in his British
Entomology.** In this specimen the super-
numerary part is a tibia, apparently moveable,
and developed from the extremity of the femur
of one of the hinder pair of legs. A similar
remarkable condition is described by Tiede-
mannff as having occurred in Melolontha vul-
guris, in which three tibiae and tarsi originated
from a single coxa of the right metathoracic
leg. Asmuss alludes also to the specimen of
Oryctes nasicornit described by Audouin,^ in
which a similar number originated from the
right prothoracic leg; and to a second example
of Melolontha vulgaris£§ in which three tibiae
and tarsi originated from a triangular, spatula-
formed femur of the right prothoracic leg. In

* Monstrositates Coleopterorum, Rigae et Dorpati,

t Bassi.
J Douraerc.
$ Seringe.
|| German
f Bassi.

** PI. 111. Apr. 1826.

tt Meckel's Archiv itir Physiologic, t. v. 1819.
p. 125. tab. 2, fig. 1.

Jf Annales de la Soc. Entom. de France, 1834.
H Doumerc.

934

JNSECTA.

another of the Melolonthida, Rhizotrogus
castaneus,* three distinct legs originated by
separate trochanters from a single prothoracic
coxa of the right side (Jig. 399, A). But per-

Fig. 399.

A, Khissotrogus castaneus; B, Scarites Pyrachmon ,
C, legs of ditto ; E, F,G, different views of a treble
tarsus of Carabus perforat us (Asmuss).

haps the most remarkable example is that given
by Lefebvref of Scarites Pyrachmon (B), in
which from a single coxa on the left side of
the prosternum two trochanters originated
(fig. 399, B, C). The anterior one, the proper
trochanter, supported the true prothoracic leg ;
while the posterior one, in the form of an
oblong lanceolate body, attached to the base of
the first, supported two additional legs equally
well formed as the true one. Dr. Asmuss has
also givori an example in Carabus perforates
of a treble fifth joint in the tarsus of 'the left
meta- thoracic leg (E, F, G), in which all the
claws of three distinct tarsi exist.

The principles upon which the modifications
of form, and the existence of supernumerary
parts depend, as attributable to retarded or ex-
cessive development, have been particularly
insisted upon by Saint Hilaire, Professor Grant,
and other comparative anatomists, in reference to
the development of the body in vertebrata, and
are equally applicable to that of the invertebrata.
That these aberrations of form really depend

Bassi.

tab

Ma8asin d'Entomologie, fascicul. 5,

upon an arrest of development is wefl show*
in the instance we formerly gave of Geotrupts
stercorarius (jig. 332), in confirmation of the
views of Savigny, respecting the different kinds
of appendages in each segment being simply mo-
difications of the same normal structure. That
retarded development is capable of producing
these aberrant forms we once satisfied ourself
by experiment made on a specimen of Sphinx
ligustri. We carefully watched a larva that
was about to undergo its change into the pupa
state, and when it was beginning to assume
that condition, retarded its development by
repeatedly touching and otherwise disturbing
it, the result of which was that the projecting
ease that usually exists on the point of the
perfect pupa of this insect was not developed
in the pupa in question, which we still possess,
and which exhibits an uniform appearance of
its exterior almost precisely similar to that of
Sphinx populi. With regard to the existence
of supernumerary limbs, it is presumed, in the
absence of any evidence that these additional
parts exist also in the larva, as we suspect they
do, as well as in the perfect insect, that they da
not originate simply by a greater development
of one part than of another during the changes
of the insect, but upon an original tendency to
the production of them which existed in the
germ itself. This opinion seems to be supported
by the circumstance, that although there is a
tendency to the reproduction of the same parts
as a normal condition of the wings in some
insects, such reproduction is not known to occur
as an abnormal condition, which appears to be
accounted for by the circumstance that the wings
themselves are simply developments of parts of
other structures, the respiratory organs.

The muscular system of Insects, like that of
other Articulata, is contained within the dermo-
skeleton. It is composed of an immense
number of distinct, isolated, straight fibres,
which are not constantly aggregated together
in bundles, united by common tendons, or
covered by aponeuroses to form distinct mus-
cles, as in Vertebrata, but remain separate
from each other, and only in some instances
are united at one extremity by tendons. The
greater number of these fibres are flat, thin,
and of the same size throughout their whole
length, a few only being slightly conical. They
are arranged parallel to each other, and form
layers, or series of fibres. These series of
fibres, or layers, we prefer to regard as sepa-
rate muscles, rather than as aggregations of
muscles, as they were formerly regarded by
Lyonet,* because we are thereby enabled to
simplify our description of the muscular sys-
tem of these animals. But besides these layers
of fibres, which form the greater part of the
muscular system, there are also certain sets
of fibres which are united by tendons to con-
stitute distinct muscles, but they are not in-
closed by aponeuroses. The muscles of in-
sects differ, then, as remarked by Straus, f from

* Traite Anatomique tie la Chenille qui ronge
le bois de Saule, 1760.

t Considerations, &c. p. 145.

1NSECTA.

935

those of the larger animals in not being in-
closed by aponeuroses, and in being formed of
fibres which are always free, straight, and fre-
quently are not connected with or arise from
tendons. There is no instance, as Straus has
correctly remarked, of a digastric muscle in
insects. Each fibre is composed of a great
number of very minute fibrillae, or fasciculi of
fibrillae, into which the fibre may be easily
torn, after it has been hardened for some time
in spirits of wine. Professor Wagner has seen
transverse striae on the fibres of insects as on
those of vertebrated animals, and we have
also observed them very distinctly on the dorsal
longitudinal fibres of Lucanus cervus, and
more particularly on the fibres of the longitu-
dinal muscles of the back, in the abdominal
segments of the larva of Odonestis potatoria ;
Professor Muller states that the voluntary mus-
cles of insects are wholly constituted by these
transversely striated fibres, each of which has
a very delicate sheath, which can often be per-
ceived forming a transparent border to the
fibre.* Those fibres which are entirely with-
out tendons are attached by their whole breadth
either directly to the flat internal surface of the
dermo-skeleton or to elevated ridges, which are
intussuscepted portions of the tegument within
the body, the apodemata of Audouin, of which
the phragmata before described are examples.
The tendons, or hard uncontractile ends of the
muscles, like the phragmata, are formed by an
elongation inwards of parts of the internal
lamina of the dermo-skeleton .f They exist
more generally in the perfect insect than in the
larva, and in the muscles of the head of the
larva than in other parts of the body. The
cause of this appears explicable by the fact that
there is a higher developed condition of body
in the perfect insect than in the larva, and in
the head of the latter than in other parts of its
body. Distinct tendons exist most frequently
in the muscles of the extremities and organs
of manducation, as in the Lucanus cervus
(fig- 388, 2), in which a large flat tendon, of
great strength, is attached to the external con-
dyle of the mandible, and on each side of
which the fibres that compose the great ex-
tensor penniform muscle are inserted. Tendons
exist also of great length in the legs of Orthop-
tera (fig. 409, «, b, c), and between the forked
processes of the thoracic segments, and the
margins of the coxae. The muscles with ten-
dons are arranged by Straus under two divi-
sions : I first, the conical, in which the tendon
is short and occupies the axis of the muscle,
where it is expanded into a broad plate, unto
which the fibres of the muscle, originating
from a broad base, and converging to one point,
are attached, and the tendon then proceeds
alone to the point of insertion ; second, the
pyramidal, in which the tendon, as in the
conical, is surrounded by short fibres, and is

* Elements of Physiology, (translation,) partiv.
p. 882.
t Straus.
$ Op. cit. p. 146.

broad and divided into several laminae ; third,
the pseudo-penniform, in which the fibres ori-
ginate in a row, and, converging, are attached
sometimes on one side, and sometimes on both
sides of a long narrow tendon ; fourth, the
penniform, which differ from the last in the
margin of the tendon being fibrous. Like the
latter the fibres originate sometimes on one
side only, and sometimes on both. Fifth, the
compound, or those which consist of several
muscles, each formed of two or more fibres,
united by a tendon, and these tendons of two
or more muscles united into one bundle ; or
in which the tendons of several bundles of
muscles are united. Unto these five forms
Burmeister has added a sixth, the cylindrical,*
the tendon of which is a flat round plate, to
which the fibres are attached on one side, and
from which a process extends on the opposite
to the point of insertion, as in the muscles of
the wings. Audouin calls these tendons epi-
dcmes, and regards them as processes of the
thorax.

The muscles of the larva present great uni-
formity of size and distribution in every seg-
ment, the motions of each of these divisions
of the body being almost precisely similar.
The differences which exist in the number, dis-
tribution, and functions of the muscles, are to
be sought for in the first four segments, which
compose the head and thorax of the perfect
insect. Thus, in the head of the larva there
is a greater aggregation of muscles than in any
other segment of its body, because a greater
number of organs exist, and consequently
require these additional muscles. The pre-
sence of a greater number of organs in this
than in the succeeding segments is readily ac-
counted for, when we remember that the head
is composed of several sub-segments, and that
the appendages belonging to it are those of
these originally distinct parts. But the situ-
ations and the form of the muscles have become
changed from those of the simple muscles of a
segment, and some have become united to
others. This may explain the cause of the
greater complexity of the muscles of the head
of the larva than of those of the other seg-
ments, and why so few are simple like those
of the abdominal regions, but, on the other
hand, are frequently complicated, and end in
tendons, and more or less resemble in form
the muscles of Vertebrata. Hence the muscles
of the mandibles are large and occupy the
greater part of the lateral and posterior region
of the cranium, the extensor muscles being
attached to the lateral and posterior surface of
the cavity, like the extensor muscles of the
legs in the thoracic segments, and the flexor
more internally to parts that correspond to the
lamina squamosa in the head of the perfect
insect, the analogies of which in the thoracic
segments are the forked processes to which
the flexor muscles of the legs are attached,
like the corresponding muscles of the man-
dibles on the head. The muscles of the three

* Manual of Entomology, (trans.) p. 24y.

936

INSECTA.

segments that follow the head, and form the
thorax of the future imago, are more numerous
and complex than those of the abdomen,
because unto those segments belong the mus-
cles of the proper organs of locomotion ; be-
sides which they contain also the rudiments of
the muscles for the future wings. The muscles
in the abdominal segments are fewer and far
more simple than in the anterior part of the
body, but their number, even in these, very far
exceeds what at first might be expected. So
numerous are they in every segment that
Lyonet, in his immortal work on the anatomy
of the larva of Cossus ligniperda, found two
hundred and twenty-eight distinct muscles in
the head alone, and, by enumerating the fibres
in the layers of the different segments, reck-
oned one thousand six hundred and forty-seven
for the body, and two thousand one hundred
and eighteen for the internal organs, thus
making together four thousand and sixty-one
muscles in a single larva. In the larva of
Sphinx ligustri we have found the muscles
equally numerous with those discovered by
Lyonet in the Cossus, but in attempting to
describe them it has appeared preferable, as
we have stated, to consider each layer of fibres
collectively as a separate muscle. In describ-
ing the muscles of the ventral portion of a
segment, we formerly* ventured to designate
them by names which were indicatory either of
their position or use, and we shall continue to
do so on the present occasion. A description
of the muscles of a portion of a segment will
suffice to convey some idea of their multiplicity
and use. We may first state generally that
those muscles which form distinct layers or act
in concert with each other, are inserted into
slightly elevated ridges of the tegument, while
a single muscle, or the tendon of many mus-
cles united together, is attached to an elevated
process of the tegument, which at that point is
thicker than in other places, and thus affords
a means of attachment. There are always
three ridges for the attachment of muscles be-
tween two abdominal segments. The middle
one is the largest, and affords both origin and
insertion to the straight or longitudinal muscles,
while the others in like manner afford origin and
insertion to the oblique ones.

On removing the fat and viscera from the
abdomen of the larva, the first layer that pre-
sents itself, and forms the interior parietes of
the body, consists of many longitudinal fibres,
which extend from the margin of one segment
to that of another as flat, straight muscles,
resembling the recti abdominales of vertebrated
animals. These muscles extend from the an-
terior margin of the sternal surface of the
second segment to the posterior part of the
twelfth ; but it is only at the anterior margin
of the sixth segment, which is in reality the
commencement of the true abdomen, that they
can properly be considered as recti muscles,
since it is at this part of the body that they
begin to be fully developed. While passing

* Phil. Trans, part ii. 1836.

through the thoracic segment they are nar-
rower, thinner, and somewhat differently ar-
ranged. They are connected anteriorly with
the head, and posteriorly with the sphincters.
They are the most powerful of all the muscles
of the abdomen, and are those which are most
concerned in shortening the body, and effecting
the duplicature of the external teguments,
during the changes of the insect. They are
also those which mainly assist in locomotion
during the larva state. There are four sets of
these longitudinal muscles, two on the dorsal
and two on the ventral surface of the body
(Jig. 400, A A). Those on the dorsal surface
are placed one on each side of the dorsal vessel
or heart, and those on the ventral one on each
side of the nervous column. The dorsal sets
extend from their attachment to the upper part
of the head through the thorax and abdomen
to the anus, in the thirteenth segment. In the
thoracic region they are narrow like the cor-
responding muscles of the ventral surface, but
when the insect is undergoing its changes they
become enormously enlarged in this region,
and form the great depressor muscles of the
wings (jig. 402, a1), which are some of the
most powerful muscles of the thorax, and ex-
tend between the meso-andmeta-phragma. The
ventral recti consist of four sets of fibres, two
on each side of the nervous cord (fig. 400,
1 , 2), and between which there is a slight in-
terspace. That set which is placed nearest to
the nervous cord and median line of the
body, is composed of only three narrow fas-
ciculi of fibres, and may be called the recti
minores (2), while the other set, situated more
externally and covering the greater portion of
the ventral surface of the segment, is broad
and powerful, and consists of from twenty to
twenty- five distinct fasciculi or fibres, and may
be called the recti majores (J). The origins
and insertions of these are different from those
of the smaller recti. The recti majores of one
segment arise from the middle ridge between
two segments (3), and are inserted close to the
origin of the corresponding muscles of the
next segment, while the recti minores arise
from the most posterior of the three ridges,
about one-fifth of a segment posterior to the
middle ridge, over which they pass, and pro-
ceed in a direction parallel to the larger ones
to be attached to part of the corresponding
ridge in the next segment. There is a small
muscle that originates from the same ridge as
the greater rectus, between it and the smaller,
which, from its passing directly to the alimen-
tary canal, and connecting that viscus to the
exterior tegument of the body, may be called
the retractor ventriculi (5). There is one of
these muscles, as shown also by Lyonet in the
Cossus, on each side of the nervous cord, from
the fourth to the eleventh segment. On re-
moving the recti, we expose two layers of very
fine thin muscles. The upper layer (B) con-
sists of nine distinct fasciculi of fibres, which
pass backwards and outwards, in a slightly
diagonal direction (6), but less diagonally than
the second layer (7), that lies immediately

INSECTA.

Fig. 400.

937

Diagram of the muscles and nerves of the ventral surface of the segments in the larva
of Sphin* ligustri. ( Newport, Phil. Trans.)

beneath the upper one. The second layer con-
sists of seven distinct fasciculi, which extend
from the anterior margin of the segment, close
to the smaller rectus, and beneath the larger,
about half their breadth across the segment.
They run backwards and outwards in a dia-
gonal direction, and are attached to the middle
ridge below the rectus as far across the seg-
ment as the outer margin of that muscle (8).
These layers of muscles when in action draw
the outer part of the anterior margin of the
following segment diagonally forwards in the
direction of the median line of the body,
and, consequently, when these muscles in se-
veral segments on one side of the body act
ogether, they bring forward the posterior por-
ion of the body of the same side, and bend

it in a semicircular direction. When these
layers on both sides of a segment act together,
they draw forwards the posterior part of the
body in a straight line. The most internal
of these layers (6) which lies close to the rectus
may be called the first oblique, and the other
the second oblique (7). Beneath this there is
another diagonal layer of fibres which originates
close to the median line of the body (9), be-
neath the nervous cord, almost in a line with
the insertion of the smaller rectus. The origin
of this set is exceedingly narrow and distinctly
tendinous, and the fibres diverging pass di-
agonally upwards and outwards, forming a flat
triangular muscle, the third oblique (9, 10),
which is attached to the posterior ridge, and
extends outwards to the margin of the greater

938

INSECTA.

rectus. These oblique muscles are the anta-
gonists of the recti, and when acting alone
draw the posterior part of each segment back-
wards and to the median line ; consequently,
when the layers of only one side are in action,
the anterior part of the body is flexed laterally
in the form of a curve, but when those on both
sides are in action the anterior part of the body
is carried directly backwards. Beneath these
oblique muscles there is another, which is
formed of only two broad fibres. It arises
from the anterior of the three ridges of attach-
ment in the median line, and passing diago-
nally forwards and outwards parallel to the third
oblique, beneath its inner margin, is attached
to the third ridge of insertion. This may be
called the fourth oblique (11). Beneath the
posterior extremity of this muscle lies the
third rectus (12), which is formed of three
fibres, somewhat broader than those of the
second or smaller rectus, but running longitu-
dinally in exactly the same direction, and hav-
ing the same origin and insertion. On re-
moving the third rectus we expose the eighth
layer of muscular fibres. This arises from the
anterior ridge, and is formed of three broad
fibres which are partially crossed at their origin
by the third rectus. It passes diagonally out-
wards, and is attached to the third ridge, extend-
ing as far as the margin of the rectus and third
oblique, by which it is concealed. This is the
fifth oblique ( 1 3). When this layer is removed,
the triangular and transverse muscles are exposed.
The triangularis (14) is composed of nine dis-
tinct fibres, which originate in a longitudinal
series that extends about half-way across the
segment. The fibres pass from their origin
diagonally backwards and outwards, with vary-
ing degrees of obliquity, and are inserted by
strong tendons into the anterior of the three
transverse ridges (16). They arise also by
distinct tendons, which indigitate with a set
of short transverse fibres, ten in number, and
which occupy the median line beneath the ner-
vous cord, and form the transversus medius(\5).
This muscle contracts the diameter of the mid-
dle of the under surface of a segment. The
triangularis, when acting with its fellow of the
opposite side, shortens the posterior half of
the ventral surface of the segment ; but when
acting singly, or in conjunction with the third
oblique, shortens that side of the segment, and
assists to bend the body laterally. It is a very
powerful muscle in locomotion, and probably
is of great use in shortening and contracting
the segments during the transformations. The
transversi abdominales (17) are six short broad
and thick fibres, that form two sets, and
originate at some distance from the median
line, posteriorly to and on the outer side of
the tendons of the third oblique, and passing
transversely outwards are inserted directly into
the tegument, about half-way across the segment.
Like the transversus medius they contract the
diameter of the ventral surface of the segment,
and bring the sides towards the median line.
Anteriorly to these muscles, but further from
the median line, is another set of six short
fibres, the abdominales anteriores (18), which

arise at some distance from the median line,
and passing transversely outwards are inserted
into the lateral part of the segment. The
abdominales laterales (19) are situated in the
posterior half of the segment. They are in-
serted by three great fasciculi of narrow ten-
dons into the inner and inferior part of the
segment, and consist of eight muscular fibres
connected in the first tendon, four in the se-
cond, and seven in the third. They form very
powerful muscles, which interlace with each
other, and originate directly from the tegu-
ment of the sides of the segment, at different
distances posteriorly to the spiracle. Some of
them (20) are much longer than others, and
the whole of them are connected with the false
feet of the abdomen. On removing these
muscles we expose the attachment of the ob-
liquus posterior (21), which is composed of
nine small fibres that pass diagonally outwards
from their origin, the anterior ridge, to their
insertion in the tegument at different distances
beneath the lateral abdominal muscles. Ano-
ther set of nine distinct fibres, the postero-
laterales obliqui (22), which originate from the
same ridge at the lateral part of the segment,
cross over the last lateral abdominal muscle,
and are inserted between it and the one im-
mediately before it. Besides these layers of
fibres there are four other sets which seem to
be particularly concerned in the function of
respiration. Of these the transversus lateralis
(28) arises tendinous from beneath the lateral
part of the great rectus, and passing upwards,
internal to the great longitudinal trachea (£),
which it crosses, is inserted beneath the ex-
ternal margin of the dorsal rectus (A). The
second transversus lateralis (24) arises pos-
teriorly to the first, crosses the trachea, and
continuing its course upwards is inserted into
the tegument of the back, about half-way
across the dorsal rectus. These muscles ap-
pear to be directly concerned in contracting
the segments during expiration. Besides these
muscles there are also the retractor spiraculi
and the retractor valvulte, which belong also to
the ventral and lateral surface of each segment.
The retractor spiraculi (25) is attached by a
long tendon (26) to the third ridge of insertion.
It is a long, fleshy, and somewhat conical mus-
cle, which passes upwards and obliquely back-
wards to the spiracle, unto the lower margin
of which it is attached, and is blended with
the circular fibres that constitute an orbicular
muscle to that orifice. It appears to be di-
rectly concerned in forcible expiration, and
draws the spiracle inwards and downwards,
and when the orbicular muscle acts in con-
junction with it assists in closing the spiracle.
The remaining muscle, the retractor valvul<s
(27), is the direct antagonist of the last. It
is composed of five distinct fibres (jig. 401, c),
which arise from the posterior margin of the
spiracle, and partly also from the attachment
of the retractor spiraculi (e\ and then, con-
verging, end in a tendon that passes diagonally
upwards and backwards, and is inserted into
a little elevation in the tegument. It is the
proper retractor or levator muscle of the spira-

INSECTA.

939

Fig. 401.

Internal view of spiracle of larva of Sphinx ligustri.

(Neivport, Phil. Trans.)

a, anterior margin of spiracle with portion of the
trachea; b, the valve; c, retractor valvulae ; e,
retractor spiraculi ; d, nerve supplying these mus-
cles.

cular orifice, and acts upon the internal valve
(b), which is situated a little within the spiracle.
This valve is a thick, moveable, dark-coloured
duplicature of the lining membrane of the
posterior border of the spiracle, and closes
on that of the opposite side (a), which is a
concave crescent-shaped margin, not acted
upon by muscles — like a cushion or pad.

These muscles of the larva of the Sphinx
differ but little from those described by Lyonet
in the Cossus. In all insects they give pas-
sage between them to the ramifications of tra-
cheal vessels, which are most extensively dis-
tributed throughout the whole body, to every
muscle, nerve, or other organ. They are also
covered in many places by numerous con-
nected vesicles filled with adipose matter,
which exist in the greatest abundance in the
larva state in all insects, occupying the inter-
stices between the muscles and tracheae. The
same general structure of the muscular system
as that which we have just described in the
Sphinx exists in all larvae that undergo a com-
plete metamorphosis, whether they belong to
the Coleopterous, Hymenopterous, or Lepi-
dopterous classes, although in the particular
distribution and form of the muscles in each
there are necessarily some differences depen-
dent upon difference of species and habit.
Thus Burmeister found a similar general con-

formation of parts in the larva of Calosoma
iycophantu* (jig. 354), one of the more per-
fect Coleoptera, both in the existence of the
rudiments of muscles for the wings and in the
longitudinal muscles of the dorsal and ventral
surfaces of the body. The muscles of the
larvae of Coleoptera, as Burmeister has re-
marked, bear a greater resemblance to the
muscles of the perfect insects than those of the
larvae of other classes. It is not difficult to
recognise in them the same general arrange-
ment of particular muscles which are after-
wards found in a more or less developed state
in the perfect insects. An admirable exem-
plification of the muscular system of Coleop-
tera is given by Straus Durckheim in his
splendid work on the anatomy of Melolontha
vulgaris, in which many of the muscles that
exist in the larva state may be distinctly iden-
tified, although greatly modified in form and
size to fit them for new modes of action, which
have been rendered necessary by the changes
that have taken place in the habits and modes
of life of the insect. Thus, as also remarked
by Straus,f the great ventral series of recti
muscles which we have just seen in the larva,
form successively the retractor muscles of the
labium, the depressors of the head, the re-
tractors or depressors of the pro-sternum, or
those which draw that part to the meso-sternum,
and the pretractors of the post-furca or trian-
gular process of the metasternum ; and, lastly,
the inferior recti muscles of the abdomen. But
in each of these instances the size and form of
the muscles are greatly altered, more especially
in the thoracic region, while in the abdominal
region those of the posterior segments exist
with less change of form than in the thoracic,
but are greatly reduced in size, and those of
the anterior abdominal segments, in which the
ventral plates of two or more segments have
become consolidated together, are atrophied
and have almost disappeared. In like manner
the dorsal recti of the larva exist in the imago
in the new form of elevators of the head,
superior retractors or elevators of the prothorax
and scutellum, and levators, depressors, and
adductors of the wings and dorsal longitudinal
recti of the abdomen. In the latter region
neither their form nor direction have been
changed, but like the ventral recti they have
been much reduced in size, because there is less
necessity for their active employment in the
perfect than in the larva state, in which nearly
the whole of the locomotive powers of the in-
dividual are entirely dependent upon those
muscles. Their form and direction have not
been changed because the direction in which
they are employed in the perfect state is pre-
cisely similar to that in which they are em-
ployed in the larva. But this is not the case
in the thoracic region, in which not only have
they been enormously increased in size and
changed in form, but their relative position
has also been altered, owing to the changes
that have taken place during the metamor-

* Trans. Entom. Society, Lond. vol. i. p. 335.
t Considerat Generales, p. 149.

940

INSECTA.

phoses in the position of parts of the tegu-
mentary skeleton, to which the muscles aie
attached. Hence the direction in which these
muscles are now required to act is also changed,
and from constituting, as in the larva, 01 ly
one continuous series of uniform muscles,
acting in one direction, in the perfect instct
they become muscles that act in several direc-
tions, at different angles of the body, and in
some parts exceed in importance and size
every other division of the muscular system.
Thus, in the thoracic region, the dorsal mus-
cles, which were parts least employed in the
larva, are those which are of the greatest im-
portance in the perfect insect, both as regards
size and function. In the larva, as we have
seen, locomotion depends chiefly upon the ab-
dominal recti ; but in the perfect insect, on the
contrary, nearly the whole of this power is
transferred to the dorsal muscles of the thorax.
Hence the arrangement of these muscles is
more or less intricate, and differs in different
classes, according to the habits of the insects.
Thus, in those classes in which the prothorax
is short, and almost or entirely anchylosed to
the meso-thorax, as in the Hymenoptera, Lepi-
doptera, and Diptera, and in which, conse-
quently, scarcely any motion of the prothoracic
segment is required, the muscles become al-
most entiiely atrophied and cease to exist, or,
as is sometimes the case, their attachments are
transferred to a different part of the tegumen-
tary skeleton.

The most generally developed form of the
muscular system of the thorax is found in the
Coleoptera, of which Straus has given so admira-
ble an illustration in his anatomy of Melolontha.
It is from his description of the muscles of that
insect that we shall chiefly derive our general
description of these parts in perfect insects.
We shall, however, for the sake of uniformity,
adopt the nomenclature applied to these parts
by Burmeister, identifying it with the names
originally employed by Straus.

The muscles that connect the head with the
thorax are contained within the prothorax (fig.
402,2), and are of three kinds, extensors,jiexors,
and retractors. The extensors, levatores capitis
(a, a), consist of two pairs, one of which arises
from the middle line of the pronotum, and
diverging laterally from its fellow of the oppo-
site side, passes directly forwards and is in-
serted by a narrow tendon into the anterior
superior margin of the occipital foramen. The
other arises further back from the prophragma.
It is a long narrow muscle that passes directly
forwards through the prothorax, and is inserted
by a tendon near the superior median line of
the foramen ; so that while this muscle and its
fellow of the opposite side elevate the head
almost in a straight line, the one first described,
when acting alone or singly, draws the head a
little on one side ; but when the whole of these
muscles act in unison, they simply elevate the
head upon the prothorax. The depressors or
flexors, depressores capitis (b\ are exceedingly
short muscles, which arise from the jugular
plate, or, when that part does not exist, from
the border of the pro-sternum, and are attached

Fig. 402.

Section of the body of Melolontha. (Straus.)

to the inferior margin of the occipital foramen.
They simply flex the head on the prothorax. The
lateral flexors, depressores externi (d\ are two
little muscles that arise from the same point as
the preceding, and are attached to the lateral
inferior margin of the occipital foramen. The
rotatory muscles, rotatores capitis (c), are two
flat muscles like the elevators, which arise, one
at the side of the ante-furca and the other from
the posterior jugular plate, and passing up-
wards and outwards are attached to the lateral
margin of the occipital foramen. The retractor
or flexor of the jugular plate is a small muscle
(e) that arises from the margin of the ante-furca,
and passing directly forwards is inserted by a
small tendon into the middle of the jugular
piece. The oblique extensor of the jugular
plate is a long slender muscle (/) that arises
from the external margin of the pronotum, and
passing obliquely downwards and forwards
traverses the prothorax and is inserted by a
narrow tendon to the jugular plate immediately

INSECTA.

941

before the retractor. The other retractor (g)
arises from the anterior superior boundary of
the pronotum, and passing downwards is in-
serted into the jugular plate between the larger
levator and the flexor capitis.

The muscles proper to the prothorax consist
of four pairs, by which it is united to the suc-
ceeding segments. The first of these, the
superior retractor, retractor prothoracis superior
(h), anses by a broad fleshy head from the
anterior external margin of the pronotum, and
passing directly backwards is inserted by a
tendon into the prophragma a little on one side
of the median line. The next muscle of im-
portance, the inferior retractor(i), arises from the
anterior border of the medi-furca, and is united
to the posterior of the ante-furca, thus forming
with that muscle part of the great recti of the
larva. This muscle must be considered as the
proper depressor of the prothorax. The eleva-
tor prot home is (/c) is narrow, pyramidal, and
arises fleshy from the lateral surface of the
prophragma. It passes downwards and is
attached by a narrow tendon to the superior
portion of the ante-furca. The rotatores pro-
thoracis are the largest of all the muscles of
this segment. They arise, one on each side (/),
by a narrow head from the posterior part of
the pronotum, and passing beneath the pro-
phragma are considerably enlarged and attached
to the tegument between the two segments,
and also to the anterior portion of the meso-
thorax. The remaining muscle proper to the
prothorax is the closer of the spiracle, an ex-
ceedingly small muscle not shewn in the draw-
ing. The other muscles of this segment are
those of the legs, which are of considerable
size. There are three distinct flexors of the
coxa (m, 7i, o). The first of these arises from
the superior lateral border of the pronotum,
the second from the superior posterior border,
the third from the sides of the prothorax, and the
fourth a little nearer posteriorly, and the whole
of them are attached by narrow tendons to the
sides of the coxa. But there is only one
extensor muscle to this part. In like manner
the extensor of the trochanter is formed of
three portions, (Jig. 403, «, b, c,) but there is
only one flexor (d) and one abductor (e}.
In the femur there is one extensor (,/), a long
penniform muscle that occupies the superior
part of the thigh, and is attached by a tendon
to the anterior posterior margin of the joint,
formed by the end of the tibia. There is also
but one flexor (g) in the femur, which, like the
preceding muscle, is penniform, and occupies
the inferior portion of the femur, and its
tendon is attached to the inferior border of the
tibia. In the tibia itself there is also one
flexor and one extensor. The flexor (i) occupies
the superior portion of the limb, and ends in
a long tendon (/) that passes directly through
the joints of the tarsus on their inferior surface,
and is attached to the inferior margin of the
claw (g). The extensor (//) occupies the infe-
rior portion of the tibia and is shorter than the
preceding muscle, like which it ends in a long
tendon that is attached to the upper margin of
the claw. Besides these muscles, which are

Fig. 403.

Muscles of the anterior leg of Melolontha vtdgarit.
(Straus.)

common to the joints of the tarsus, there are
two others belonging to the claw, situated in
the last joint. The first of these, the extensor
(m), is short and occupies the superior portion
of the last phalanx of the tarsus, and the other,
the flexor (n\ is a much longer penniform
muscle, which occupies nearly the whole of
the upper and under surface of the posterior
part of the phalanx, and is attached, like the
long flexor of the tarsus, to the inferior part of
the claw. These are the muscles of the pro-
thorax and its organs of locomotion, as shewn
by Straus, and exemplify the extent unto which
the muscular system is developed in perfect
insects. The muscles of the other segments of
the thorax differ considerably from these in
their form and arrangement, but the length
unto which this article has already been carried
prevents us from entering particularly into their
consideration. The great depressor muscle of the
wings, musculus metanoti (fig. 402, x\ occupies
with its fellow the chief portion of the dorsal
surface of the meso- and meta-thorax, and the
elevators and pretractors, musculi laterales me-
tanoti (y,y\ the lateral superior parts of the
same segment, and descending obliquely back-
wards are attached to the metaphragma and
base of the post-furca. The other muscles
which belong to the legs and those that connect
the thorax to the abdomen are of considerable
size. One of those of the posterior legs, the
second flexor (z), is seen immediately behind
the muscles of the wings, and the extensors
(a, «) at the posterior part of the segment. In
the abdomen the chief muscles are the dorsal

942

INSECTA.

recti (c, c) on the upper surface, and the corres-
ponding ones on the ventral, which are now
chiefly subservient to the motions of the organs
of generation.

From the number and complexity of the
muscles in these " miniatures of creation" —
insects — we feel less surprised at the agility of
their movements and the variety of motions
which many of them perform, and less asto-
nishment at the wonderful strength which
many species possess. But still there are
instances of some of them possessing a degree
of power that is almost incredible. The great
stag-beetle, Lucanus cervus, which tears off
the bark from the roots and branches of trees,
has even been known to gnaw a hole an inch in
diameter through the side of an iron canister in
which it was confined, and on which the traces
of its mandible were distinctly visible, as proved
by Mr. Stephens, who exhibited the canister at
one of the meetings of the Entomological So-
ciety,* an indication of an amount of strength
possessed by these insects of which before we
could have had no conception. But hardly
less surprising is the strength possessed by
Geotrupes stercorarius, which can support un-
injured, and even elevate an immense weight,
and make its way beneath almost any amount
of pressure. In order to ascertain the amount
of strength possessed by this insect, we have
made a few experiments from which it appears
that it is able to sustain and escape from
beneath a pressure of from twenty to thirty
ounces, a prodigious weight when it is remem-
bered that the insect itself does not weigh even
so many grains. But this amount of strength
is not confined to the short thick-limbed beetles.

We once fastened a small Curabus ( • — ?),

weighing only three grains and a half, by means
of a silken thread to a small piece of paper,
upon which the weight to be moved was placed.
At a distance of ten inches from its load the
insect was able to drag after it, up an inclined
plane of twenty-five degrees, very nearly eighty-
five grains. But when placed on a plane of
five degrees it drew after it one hundred and
twenty-five grains exclusive of the friction to
be overcome in moving its load.

The motions of the insect in walking as in
flying are dependent in the perfect individual
entirely upon the thoracic segments, but in the
larva chiefly upon the abdominal. Although
the number of legs in the former is always six,
and in the latter sometimes so many as twenty-
two, progression is simple and easy. Miiller
statesf that on watching insects that move
slowly he has distinctly perceived that three legs
are always moved at one time, being advanced
and put to the ground while the other three
propel the body forwards. In perfect insects
those moved simultaneously are the fore and
hind feet on one side and the intermediate foot
on the opposite, and afterwards the fore and
hind feet on that side and the middle one on
the other, so that, he remarks, in two steps the

* Transact. Ent. Soc. Lond., vol. ii. Journal of
Proceedings, p. xxii.
t Elements of Physiology, p. 970. (Transl.)

whole of the legs are in motion. A similar
uniformity of motion takes place in the larva,
although the whole anterior part of the body is
elevated and carried forwards at regular dis-
tances, the steps of the insect being almost
entirely performed by the false or abdominal
legs.

Inflight the motions depend upon the meso-
and meta-thoracic segments conjointly, or en-
tirely upon the former. The sternal, episternal,
and epimeral pieces, freely articulated together,
correspond in function with the sternum, the
ribs, and the clavicles of birds.* The thorax
is expanded and contracted at each motion of
the wings, as in birds and other animals, and
becomes fixed at each increased effort as a
fulcrum or point of resistance upon which the
great muscles of the wings are to act, thus
identifying this part of the body in function as
in structure with that of other animals.

The Nervous System. — Comparative exami-
nations of the nervous system in Articulata,
and the changes which it undergoes, more es-
pecially in Insects, as well as the existence in
it of parts which we regard as analogous to the
motor and sensitive portions of the spinal cord
in vertebrata, have invested this division of our
subject with more than a common amount of
interest.

It has been shewn in a former part of this
work,f that in Articulata the most rudimentary
condition of the nervous system exists in the
form of two longitudinal cords, extended along
the median line of the under surface of the
body, parallel with each other, and nearly close
together, excepting at their anterior part, where
they diverge, and pass upwards, to embrace be-
tween them the commencement of the alimen-
tary canal. In a more advanced stage of or-
ganization each of these cords has a series of
enlargements or ganglia in its course, situated
at certain distances apart, and varying in num-
ber according to the number of segments into
which the body of the animal is divided.
These enlargements correspond precisely in si-
tuation in both cords, so that the nervous sys-
tem in this condition may be described simply
as composed of two knotted, parallel cords.
The enlargements in one cord are either placed
close to the corresponding ones in the other, or
are separated only by a very slight interspace.
This is the form in which the nervous system
exists, as we have seen, in the Talitrus,J in
which the ganglia are approximated together,
but are still distinct from each other, and form
a double series of enlargements, united by in-
tervening cords. This is also the condition in
which the nervous system exists in its most ru-
dimentary state in the larva of hexapodous
insects. But these parallel cords, which toge-
ther form the analogue of the cerebro-spinal
system of vertebrata, and correspond one to
each side of the body, are not in themselves
simple structures, each one being composed of

* Bennet on the anatomy of the thorax in insects,
and its function during flight, Zoological Journal,
vol. i. p. 394.

t Art. CRUSTACEA, ENTOZOA, ANNELIDA.

J CRUSTACEA, vol i. p. 763, fig. 391.

INSECTA.

943

two distinct columns of fibres, placed one upon
the other, and closely united together in every
instance. The under or external column,
which is nearest to the exterior of the body, is
that in which the ganglia or enlargements are
situated. The upper one, or that which is
internal and nearest to the viscera, is entirely
without ganglia, and passes directly over the
ganglia of the under column without forming
part of them, but in very close approximation
to them. In some species, as in the larvae of
Timarcha tenebricosa, (Jig- 404, 2, 3, 4,) and
Proscalabteus vulgaris, among the Coleoptera,
and of the Bee and other Aculeate Hymenop-
tera, this column is more apparent than in the
larvae of Lepidoptera, in which it is indistinctly
seen, excepting when it is beginning to pass
over or is just leaving the surface of a ganglion.

Fig. 404.

A

be analogous to the motor column of verte-
brata, and the external or under one, in which
the ganglia are situated, we regard as the ana-
logue of the sensitive. Thus the two cords are
each composed of a motor and a sensitive co-
lumn, and represent, we believe, the cerebro-
spinal system of vertebrata. In the Aculeate
Hymenoptera, the ganglia of the cords are in a
state of development similar to those of the
Talitrus ; they are approximated together late-
rally, but still remain distinct from each other,
and thus present a transitory condition in the
larva state of an insect similar to their perma-
nent one in the lower Crustacea. In the fimar-
cha, the anterior pair, or supra-cesophageal gang-
lia, still continue distinct from each other, (fig.
405, A A,) and retain their rudimentary form,
as in the Talitrus, and the cords are also sepa-
rated ; but the several pairs of suboesophageal
ganglia have each coalesced into a single mass.

Fig. 405.

Nervous system of the larva of Timarcha tenebricosa.
B, natural size.

The ganglionless upper or internal column
of fibres is the part which we believe to

The supra-cesophageal ganglia, or brain of larva of
Timarcha tenebricosa. (Newport, Phil. Trans.)

A similar coalescence of the ganglia, but car-
ried to a less extent, exists in the larvae
of Lepidoptera, in which the form of the ner-
vous system of insects has been most frequently
examined. Malpighi and Swammerdam ex-
amined this structure in the Silkworm, and
Lyonet in the larva of the Goat-moth, Cossus
ligniptrda. We have also examined it in the
larva of the Privet Hawk- moth, Sphinx
iigustri, in which we shall now describe its
general form and distribution.

Cord and nerves of the larva. — In the
larva of the Sphinx, (fig. 406,) as in
most others of the vermiform type, the nor-
mal number of double ganglia is thirteen.
The anterior pair (A) situated above the eso-
phagus, represent the brain, and the first of
those which are situated below it, (ft,) the
medulla oblongata. These are the proper
ganglia of the head or first segment, and the
cords by which they are connected together,
and which descend one on each side of the
O3sophagus, in like manner represent the crura.
Posteriorly to the medulla oblongata. which we
shall distinguish as the first suboesophageal
ganglion, the cords pass directly backwards into
the second segment, where they form the se-
cond suboesophageal ganglion (2). They then

944

INSECTA.

diverge a little from each other, and include
between them the insertions of the first set of
diagonal muscles, and at the posterior part
of the third segment again approach each
other, and form the third ganglion (3).

Nervous system of the larva of Sphinx ligustri.
(Newport, Phil. Trans.)

They then again diverge, and continuing their
course into the next segment, pass on each side
of the insertion of a second set of muscles, and
approaching at the hinder part of the fourth

segment form the fourth ganglion, (4,) from
which they continue their course side by side,
and in the next segment form the fifth and last
ganglion, (5,) that enters into the composition
of the thoracic portion of the nervous cord in
the perfect insect. From the fifth ganglion the
cords are continued in a direct line, into the
sixth, seventh, and succeeding segments, form-
ing in each a double ganglion, to the eleventh,
where they form the terminal ganglion (11,12).
This is considerably larger than any of the pre-
ceding, being in reality composed of two dis-
tinct pairs, which originally were separated
from each other by intervening cords, and be-
longed to the eleventh and twelfth segments,
but which seem to approach and become closely
approximated to each other during the earlier
period of the larva state, as suggested by Dr.
Grant, and supported by the fact that these
ganglia are found more or less approximated
together in different individuals, the terminal
ganglion in some being distinctly formed of two
pairs, scarcely united, and in others so com-
pletely coalesced as hardly to be distinguished.
In other Lepidoptera, as in Odonestis potatoria
and Lasiocampa, neustria, and as represented
also by Lyonet, in Cossus ligniperda,* the
ganglia continue distinct, and are separated by
a very short portion of the cords. But in the
Timarcha, the eleventh and twelfth ganglia
have completely coalesced, and it is remark-
able that they are also united even in the
rudimentary form of the nervous system in the
aculeate Hymenoptera, as in the larva of the
bee, and even in its still more rudimentary state
in the larva of Ichneumon Atropos, in both
which there are originally thirteen distinct pairs
of ganglia, including the supra-cesophageal ones,
although Burmeister has imagined that the
apodal larvae of Hymenoptera have a nervous
system without ganglia,f similar to what he has
observed and figured in the larvae of some Dip-
tera. It was shown by Swammerdam,]; that in
the Lamellicornes, as in Oryctes nasicornis,
the cords are united laterally, and do not extend
beyond the fourth segment, from whence the
nerves radiate into the abdomen. In Dyticus,
according to Burmeister, § the two approxi-
mated cords are very short, and the pairs of
ganglia are contiguous to each other, and he
has found a similar form of the nervous system
in the Hog-beetles, Calandra sommeri, in which
there are twelve pairs of closely approximated
subcesophageal ganglia. The supra-o2sophageal
pair in this species are distinct, as in Timarcha,
but each pair of the subresophageal has co-
alesced into a single mass, as in that insect, and
the whole do not extend beyond the fifth seg-
ment, from whence the nerves radiate into the
abdomen, as in the Lamellicornes. These are
the conditions which the double cord presents
in the different classes. In describing the
nerves that proceed from it, we shall divide them
into those of the head, the thorax, the abdomen,
and the organic functions.

* Plate ix.

t Manual, (translat.) p. 279.

i Biblia Xatura, Tab. xxviii. fig. 1.

§ Op. cit.

INSECTA.

945

Nerves of the head. — When the first pair of
ganglia, which always constitute the brain, are
viewed from above, they each present a> convex
uniform appearance, and are distinguished
from each other by a depression between them,
which is more apparent on their anterior than
thejr posterior surface, and is occasioned by the
lateral part of each lobe or ganglion being car-
ried a little forwards, so that the two lie across
the oesophagus in a curved or lunated direction.
On their under surface they are concave, to
adapt them to the form of the oesophagus,
above which they are situated. From the an-
terior and lower part of each lobe originate
four remarkable nerves, which belong to the
organs of sense and the viscera. The first and
largest of these, the optic, passes a little for-
wards and outwards to the siemmata, a little
behind the mandibles; the second, the anten-
nal, passes a little more anteriorly, to the palpi-
form antenna; the third, and most inferior,
descends at the side of the pharynx, and uniting
with its fellow of the opposite side forms a
loop or collar around the oesophagus, to the
under-surface of which it distributes a few fila-
ments. We consider it as analogous to the
glosso-pharyngeal nerve of vertebrata. The
fourth is situated between the second and third.
It passes a little forwards from its origin, and
then ascending above the pharynx, meets its
fellow of the opposite side, with which it forms
a minute ganglion, from the hinder part of
which a single nerve passes backwards (6)
beneath the brain, in the median line above the
oesophagus, to the stomach and viscera. This
nerve was discovered by Swammerdam,* who
called it the recurrent, from the manner in
which it originates and is distributed, and it
was afterwards minutely figured and described
by Lyonet. Miiller has since described it
minutely, and figured it in many species, in his
paper on the sympathetic nerves of insects, as
the proper visceral nerve, analogous to the sym-
pathetic. In a paper in the Philosophical
Transactions in 1832, we described it as the
vagus,]- of which we believe it is the proper
analogue. At that time we were led to sup-
pose that it had previously been so described
by Straus Durckheim, but such, as we have
since found, was not the case. Wre shall pre-
sently return to our description of this nerve,
in the perfect insect, as belonging to those of
the organic functions. Besides these four pairs
of nerves from the anterior part of the
brain, there is also one minute pair from the
posterior, which is directed backwards, and de-
veloped on each side of the head into two pairs
of little ganglia, (a,) which constitute part of
the sympathetic system. The first of these
ganglia was discovered and rudely figured by
Swammerdam,^ and afterwards more correctly
by Lyonet, and the second by Straus Durck-
heim. We have designated them from their
situation the anterior lateral ganglia.^

* Op. cit.tab. xxviii. fig 2.
t Part 2, p. 386.
J Op. cit. tab. xxviii. tig. 3 i.
§ Philosophical Trans, p. 2, 1832, page 38?.
VOL. n.

These are the proper cerebral nerves of the
larva, and belong to the senses and organic func-
tions. The medulla oblongata, or first subceso-
phageal ganglion, also gives origin to four pairs
of nerves. The most anterior pair of these is
given to the labium ; the next to the palpiform
maxillae; the third, the analogue of the fifth of
vertebrata, conjointly to the muscles of the
mandibles and maxillae; and the fourth, the
most posterior pair, to the silk vessels, the pro-
per salivary organs of the larva.

The nerves of the thorax belong to the se-
cond, third, fourth, and fifth suboesophageal
ganglia, and their intervening cords. The first
pair of nerves from the second ganglion (2)
are exceedingly small, and are given to the
retractor muscles of the head. The second
pair (c) are large, and are divided into many
branches that are given to the whole of the
muscles of the lateral and superior part of that
segment, and the third (d) are directed back-
wards, and supply the anterior or prothoracic
legs. The third ganglion (3) produces also
three pairs of nerves. About midway between
the second and third ganglion the cord pro-
duces on each side a single nervous trunk (f),
which is directed a little backwards, and unites
at an angle with the first nerve from the third
ganglion. These together from a single trunk,
which in the early stage of the larva is exceed-
ingly small, but increases much in size as the
period of changing into the pupa state ap-
proaches. It is the first alary nerve, and is
given to the future anterior pair of wings, and
is now distributed among the muscles of the
anterior part of the segment. It is also con-
nected with one set of the transverse nerves (e\
which exist in each segment loosely attached
to the cords, and which we shall describe more
particularly hereafter. The second pair of
nerves from this ganglion produce each at their
base a small branch, which has the appearance
of a distinct nerve, and which is distributed
laterally to the deep-seated muscles, while its
main trunk (g) is given to the second, or meso-
thoracic pair of legs. Half-way between the
third and fourth ganglion the cord again pro-
duces on each side a single nervous trunk («'),
which, like the corresponding one in the pre-
ceding segment, is directed backwards, and
unites with the first nerve from the third gan-
glion. It is the second alary nerve given to
the muscles of the future second pair of wings.
Like the corresponding nerve in the preced-
ing segment, it is very small during the early
period of the larva state, but is greatly en-
larged as the period of transformation ap-
proaches. It also unites, like the former, with
a set of the transverse nerves (h\ and then
passes outwards about midway across the recti
muscles, between which it penetrates, and
pursues its course upwards to the lateral and
dorsal muscles of the segments, and which are
to act upon the future wings. The second
nerve from the ganglion divides, like the cor-
responding one from the ganglion of the pre-
ceding segment, into two branches, one of
which (A;) crosses the smaller rectus muscle,
and passes beneath the larger to the dorsal

3 Q

946

INSECTA.

muscles of this segment, and the second is
given directly to the third pair of legs. The
fifth ganglion (5), which is situated at the an-
terior part of the fifth, or thoracico-abdominal
segment, belongs, as we shall hereafter see, to
the thorax. Like the abdominal ganglia it
gives off two distinct pairs of nerves, the an-
terior of which crosses the smaller, and de-
scends beneath the larger rectus, and is dis-
tributed to the muscles which afterwards con-
nect the thorax and abdomen of the perfect
insect; and the second, a smaller pair, passes
diagonally backwards below the third rectus,
to the triangular and transverse abdominal
muscles. These are the nerves of the thorax
in the larva of the Sphinx. In other species
there are some marked differences in their
mode of distribution. Thus, in the Cossus
ligniperda, as shown by Lyonet, the first and
second suboesophageal ganglia are closely ap-
proximated together, and have no intervening
cords, and their nerves, consequently, pass di-
agonally backwards, and not transversely, as
in the Sphinx. The nerves for the future wings
are not derived, as in the Sphinx, from the
ganglionless parts of the cord, but from the
ganglionated portion alone, and the distance
between the fourth and fifth ganglia is con-
siderably shortened. In the larva of the nettle
butterfly, Vanessa urtic<e, as formerly shown
by us,* the alary nerves are derived directly
from the cord itself, between the second and
third and third and fourth ganglia, but they do
not unite, as in the Sphinx, with a nerve from
the next ganglion, but only with the transverse
nerves. But in some of the Bombycid<z, as in
Odonestis potatoria, we have found the same
connexion to exist between the alary nerves
and those of the ganglia, as in the Sphinx, and
a similar union also between them and the trans-
verse nerves. This is particularly interesting from
its proving that three distinct branches enter
into the formation of the nerves for the future
wings. We have found a similar double ori-
gination of the alary nerves in the vermiform
larvae of Hymenoptera, as in Athalia centifolia;
and Burmeister has detected a similar condition
of the same nerves in the larva of one of the
Coleoptera, Calosoma sycophanta, and, as we
shall presently see, a similar condition exists
even in some perfect insects. Burmeister, who
observed these connexions of the nerves in
Calosoma, and called them auxiliary connect-
ing nerves, has somewhat curiously remarked
that he believes they have riot before been ob-
served in any insect, particularly in the Lepi-
doptera, in proof of which he adduces Lyonet's
description and delineation of the nerves in
Cossus, in which, as we ourselves have found,
they certainly do not exist. The reason for this
difference of manner in which nerves that are
given to similar parts in insects of the same
order and family originate, is a matter worthy
of much consideration.

Nerves (if the abdomen. — All the nerves from
the sixth to the terminal ganglion belong to the
abdomen, and are nearly uniform both in num-

* Phil. Trans. 1834.

ber and distribution In the segments. Each
ganglion produces one pair of large, and one
of small nerves, entirely distinct from the se-
ries of transverse nerves (o) that lie loosely
upon the cord.

It will be remembered that, according to
our view of the structure of the cord and
nerves, each nerve from a gangliated portion
of this cord is formed of one set of fibres from
the external or gangliated part, and one from
the aganglionic or motor column (Jig- 400),
which passes over the ganglion (a), but so closely
attached to it as to appear as if it formed a part
of that structure. These, therefore, are quite
distinct from the transverse nerves (c). The an-
terior pair of these nerves from the gangliated
cord pass laterally across the smaller rectus,
having first received a minute branch from the
transverse nerves, and, while passing beneath
the larger rectus, each one gives off its first
branch (p), and when passing between the
second and third oblique muscles its second
branch (q\ which is directed forwards, and a
little farther onwards its third (r), and its
fourth (s), which are directed backwards. The
main trunk (t) then crosses the great lateral tra-
chea, and having received another filament
from the transverse nerve (?i), divides into two
branches (£), which pass upwards between
the dorsal oblique and recti muscles, and
are divided into numerous ramifications.
About midway across the dorsal recti some of
the branches form a small plexus (w), before
they are ultimately distributed to the muscles
and tegument. The two first divisions of this
nerve merit particular attention. The first (p)
passes backwards beneath the greater rectus,
and divides into two branches. The anterior
one (v} is distributed to the four oblique mus-
cles, and to the external or under surface of
the rectus, which, as we shall presently show,
is supplied on its internal surface from the
transverse nerves (/). The second division
passes backwards and is given, one portion to
the under surface of the smaller rectus, and
the other to the great oblique, while the ter-
mination of this portion (w} is continuous with
a filament of the second branch of the trans-
verse nerves (/). Some branches from this
nerve pass between the triangular and second
oblique muscles (x), and others are given to
the latero-abdominal. The second branch (q)
of the great moto-sensitive nerve passes be-
neath the great oblique, and gives off branches
to the transverse abdominal muscles (y\ and
the latero-abdominal (2), while another sup-
plies the latero-abdominal (31) and the oblique
constrictor of the spiracle (25), and then di-
vides into two portions, one of which is given
to the retractor valvula (27), and the other
to the transverse lateral muscles (24). The
divisions of this branch of the moto-sensitive
nerve are particularly interesting. Before dis-
secting these nerves we had supposed that
the constrictor of the spiracle (25) and the
retractor of the valve (21) were supplied by
the transverse nerves, and hence were surprised
on finding that their nerves were derived from
the great moto-sensitive of the gangliated cord,

INSECTA.

947

by which it is presumed they are thus endowed
with voluntary power and sensation. But on
reflection it will appear that this ought really to
be the case. To enable the insect to make a
forcible expiration and close its spiracle, which
is evidently an act of volition, the great con-
strictor of the spiracle ought to be endowed
with voluntary nerves. On the other hand,
since, as we know from experiment that the
insect has a voluntary power of closing, it must
also have a similar power of opening the orifice,
and, consequently, the retractor valvulse ought
to be supplied from the same source as the
constrictor. The remaining portion of the
trunk of these nerves passes forwards and out-
wards, crosses the retractor of the spiracle
and gives off its third branch, which is again
divided, and sends one portion backwards to
the anterior (18) and the transverse abdominal
muscles (17), and the other forwards to the
transverse lateral (23). The remaining portion
of the nerve is distributed to the dorsal muscles
and teguments. The second nerve from the
gangliated part of the cord is much smaller
than the first. It passes diagonally backwards
and outwards, and divides into two branches,
the first of which is given to the latero-abdo-
minal muscles, and the second to the triangular
and transverse median, while the other (&)
passes downwards and outwards, and is con-
tinuous with part of the third branch of the
transverse nerves (i).

Besides the nerves thus described as belong-
ing to the moto-sensitive cord in the thorax and
abdomen, there are others that merit particular
consideration, both from the circumstance of
their lying loosely above the cord, and from
their special distribution. These nerves, which
were formerly distinguished by us* as trans-
verse nerves from the direction of their prin-
cipal branches, and as respiratory from their
special distribution to the respiratory organs,
were discovered by Lyonet, and are delineated
and particularly described in his anatomy of
Cossus ligniperda. There is a plexus of them
in every segment of the thorax and abdomen.
Like the alary nerves of the cord in the thorax,
there is a little difference in the distribution of
some of them in the Sphinx from that of the
corresponding plexus in the Cossus. In our
earlier examinations of these nervesf we be-
lieved them to originate from the posterior part
of each ganglion of the cord, and this also was
the opinion of Lyonet with reference to those
in the Cossus which constitute the second and
third plexus of the thorax, and the last of the
abdomen, and which, he expressly states, do
not come from the cords, but from the ganglia. J
We have since been satisfied that the plexus in
one segment is connected with that in each
succeeding one by means of a minute filament,
derived from the transverse portion of these

* Phil. Trans. 1832, part ii. p. 389, and 1834,
part ii. p. 401, also 1836. part ii. p. 544.

t Op. cit. 1832.

t Traite Anat. de la Chenille, 1760, also 1762,
p. 98 and 204.

nerves, and which, passing laterally over and
very close to the ganglion of the cord, joins its
fellow of the opposite side, in the middle line
behind it, to form the longitudinal portion of
the next plexus, such filament gathering a few
additional ones from the upper or motor sur-
face of the cords. Hence, as we have stated,*
these nerves are of mixed character, and con-
tain some voluntary motor fibrils. Each plexus
is formed of these two filaments, which, closely
approximated together, pass backwards along
the median line above the cord, until they
arrive just before the next ganglion, where they
diverge nearly at right angles, and are closely
approximated to another series of fibres that
runs in a commissural manner transversely
across the body, from one side to the other.
On each side a filament (e) is given off from
the transverse nerves to unite with the moto-
sensitive (f) close to the inner side of the
smaller rectus. Near the external margin of
that muscle it gives off another branch
(g), which passes forwards upon the mus-
cle, unto which it gives filaments, and then
turns suddenly outwards (^), to join a branch
from the great moto-sensitive nerve, while a
smaller branch is continued onwards to supply
the remainder of the muscle. This union is
exceedingly interesting, and illustrates the fact
that, even in the Invertebrata, some of the
nerves in one part are connected by loops with
those in others, as noticed by physiologists in
the Vertebrated classes. The next branch (i)
of the transverse nerves is equally interesting
from the same circumstance. It is continuous
in the same manner with another branch of the
moto-sensitive (k). This branch is composed
of fibres that are approximated to the transverse
trunk, and pass some from without inwards,
and others from within outwards, to form the
nerve (i), leaving between them at its base a
little triangular interspace, covered by a mem-
brane and resembling the plexus (6). This
nerve passes directly forwards until it arrives
at the insertion of the greater recti (j), where
it gives off a large branch to those muscles,
and then passing beneath the oblique muscles,
unto which it is distributed, and to the trian-
gularis, becomes connected by loops with the
second pair of moto-sensitive nerves (/c) in the
preceding segments. Neither of these two
branches have been delineated by Lyonet in
the Cossus. The next branch (1} of the trans-
verse nerves is given to the tracheae and visceral
surface of the great rectus, after which the
trunk of the nerve passes outwards until it
arrives at the tuft of trachea! vessels which are
situated just behind the spiracle (F). It there
divides (m) into two branches, one of which
passes on each side of these tracheae. Some
filaments from the anterior branch pass inwards
along the trachea towards the alimentary canal,
while others are distributed to the transverse
lateral muscles, dorsal recti, and lateral mus-
cles of the dorsal vessel. The other division
of the nerve also gives branches to the tracheae

* Phil. Trans, part ii. 1836.
3Q 2

948

INSECTA.

and to the moto-senskive nerve (w), and, like
the other, the obliqui and recti muscles and
dorsal vessel. This division of the transverse
nerve into two branches before it arrives at the
trachea is not figured by Lyonet in the Cossus.
In his delineation the transverse nerve crosses
the trachea singly, posteriorly to the spiracle,
where it communicates, as in the Sphinx, with
the first moto-seositive nerve from the gan-
gliated cord, but does not give off a large
branch anteriorly to the spiracle. We are thus
particular in our description of these nerves,
because it has sometimes been supposed that
their distribution is precisely the same in all
Lepidoptera, but which it is thus seen is not
the case.

Such, then, are the origins and the distri-
bution of the nerves in the larvae of Lepidop-
tera, into the description of which we have
entered thus minutely in order to show that
some nerves are distributed, more especially
than others, to parts concerned both in the
organic functions and the voluntary motions of
the animal, and that others are given almost
exclusively to parts that minister entirely to
sensation and volition. Of the first kind are
those which we have designated respiratory
nerves ; of the second are those we have described
as the moto-sensitive, the proper nerves of f the
cord. The distribution of the first so especially
to the respiratory organs is a circumstance which
justifies us, we think, in still regarding them by
that designation, whether they be considered
as constituting a distinct system, as formerly
supposed, or as being of a mixed character,
connecting the organic with the voluntary func-
tions of the body, as suggested by Professor
Miiller, and as we now regard them. In our
earliest inquiries into the structure and uses of
parts of the nervous system in insects, we first
described these nerves with reference to func-
tion, as respiratory nerves, but it was after-
wards suggested by Professor Grant that these
* might be motor nerves/ an opinion founded
analogically upon the existence of a loose and
easily detachable structure situated upon the
nervous cord in the Scorpion and the Centi-
pede, and which was imagined to be the motor
tract, but which has since been shown to belong
to the vascular instead of the nervous system.
The structure which we regard as the true
motor column, we have always found in close
apposition with the sensitive, and in no instance
lying freely upon or loosely attached to it.
That the transverse nerves are indeed of a
mixed character may readily be inferred from
the description we have above given of their
peculiar structure, which was in part noticed by
Lyonet,* who called these nerves brides
epinitres. It is distinctly seen that three sets
of fibres enter into the composition of them.
The commissural set, which runs transversely
across the cord to each side of the body, is per-
fectly distinct from the longitudinal that form
the single loosely attached longitudinal portion
of each plexus above the cord. The pecu-

* Op. cit. p. 201.

liarity of their distribution is also as remarkable
as their structure. We have seen that they are
given to the muscles of the wings, not sepa-
rately, but approximated to other nervous
trunks, which are derived both from the com-
pound cord and from the ganglia; that they are
given to the muscle that connects the alimentary
canal to the general muscular structures of the
body ; that they are connected with the nerve
from ganglia of the cord in each segment,
are also given separately to the organic struc-
tures, the tracheae and dorsal vessel ; and that
these nerves alone follow the course of the
tracheae inwards to their distribution on the
alimentary canal ; from all which it may be in-
ferred that their function is certainly in part
organic; while the fact of their being also in
part continuous with some of the nerves from
the cord which are distributed to voluntary
muscles renders it equally apparent that they
are in part also connected with the function of
volition.

The nervous system of the perfect insect
differs considerably in the size and relative
position of its parts from that of the larva.
Instead of its being almost equally distributed
to every segment of the body, the greater pro-
portion of it is removed forwards and concen-
trated in the head and thorax. This concentra-
tion takes place in every insect that undergoes
a complete metamorphosis. The great principle
upon which the development of the nervous
system depends, is the approximation and
concentration of the ganglion of the different
segments, the shortening of the cords, and the
formation of new trunks, by the enlargement,
the changing of place, and the aggregation of
several nerves into one bundle, occasioned
and rendered necessary by other changes that
take place in the body at a certain period. A
concentration, therefore, of the nervous matter
is regarded, both in the perfect and larva con-
dition, as a proof of a higher stage of develop-
ment in an insect than when the nervous matter
is more equally distributed. On this account
partly it is that the Coleoptera are considered
the higher forms of insects, because, in addition
to a more perfectly developed form of the tegu-
mentary skeleton, there is also in them a concen-
tration of the nervous masses, which, in the
more perfect species of the order, are confined en-
tirely to the region of the head and thorax. This
is the case even in the larva condition of some
of the Lamellicornes, Scarabceidte, Geotrupida:,
and Melolonthidae, in which the nervous masses
are confined to the first five segments, and the
nerves radiate from them into the abdomen, as
formerly shown by Swammerdam in Oryctes
nasicornis. But although an aggregation of the
nervous masses into one region of the body is
usually, it is not invariably, a proof or an
accompaniment of high development; since a
condition similar to that of the larvae of the
Melolonthida exists even in some of the lowest
forms of larvae of other orders, as in the larvae
or common maggots of Diptera, and in some
of the perfect insects, as in the Gad-fly, (Estrus
equi; while, on the contrary, a lengthened

INSECTA.

949

form of cord and distribution of ganglia exists
even in many of the more perfect Coleoptera,
as in the Carabidic (fig. 407) and Hydrophi-

Fig. 407.

Nervous system of Carabus monills.

lidie. Swammerdam long ago showed this
aggregation of nervous matter in the maggot of
the cheese-hopper, and Burmeister has since
observed even a more concentrated form in the
larva of Eristalis tenax, the rat-tailed maggot

of cesspools and privies. In the latter instance,
as seen also by ourselves, the nervous system
consists of a short nodulated cord, which does
not extend beyond the three very short thoracic
segments, and the greater portion of the body,
the nine posterior segments, receives its nerves
directly from the cord in the thorax, and not
from a ganglion in each segment. This is a
circumstance the more remarkable, if, as be-
lieved by Straus and others, the existence of
the ganglia is regulated entirely by the mobility
of the segments or the existence of appendages,
because, in these instances, the extremities of
those segments in which the cord is placed
are undeveloped, or only, as in Eristalis, in
the most rudimentary form and almost useless,
the sole organs of locomotion being the abdo-
minal or false legs, while in the common
maggots (Jig. 358) both the abdominal and
thoracic legs are absent, and locomotion is
performed equally by every segment of the
body. In addition to this it may be stated that
in some of the active larvae of the most perfect
Coleoptera, as in the Carabida, there is a
lengthened form of cord and a ganglion in
almost every segment of the body. Burmeister
found the brain and twelve sub-cesophageal
ganglia in the larva of Calosoma, and yet the
insect possesses only six thoracic legs, the
abdominal ones being entirely absent, excepting
only the caudal leg or extremity of the abdo-
men, in which segment there is no ganglion.
These facts will prove that although a concen-
trated form of the nervous system usually exists
with a more perfect development of other parts
of the body, it exists also when the develop-
ment of other parts is imperfect. It is not,
then, the immobility of the segments that regu-
lates the disappearance of the ganglia, since,
as Burmeister has justly remarked, there is as
little motion of the segments of the abdomen
in the perfect Carabid<s and Lucanidee, in which
cords and ganglia exist, as in the Melolonthidte,
in which they are absent. Neither is it neces-
sary that ganglia should be present as a means
of supplying energy in segments upon which,
as in Eristalis, the entire locomotive power of
the insect depends, or that when ganglia are
present they are necessarily connected with the
function of motion.

The most concentrated form of the nervous
system in all its states exists in the Lamelli-
curnes, the Scarabocidte, and Melolontlrida ;
but it is remarkable that even in these the
development of the brain or supra-cesophageal
ganglia is less perfect in the larva state than
any of the other ganglia, and is not more
advanced than in the Lepidoptera, in which,
in the caterpillars of the nettle butterfly, Vanessa
iirtictf, so late as the middle of the last period
of the larva state we have found these ganglia
very distinct from each other, being only
approximated in the middle line by their convex
surfaces. Towards the latter period of the
larva state they become rapidly more and more
united, and at the time of change have formed
one continued mass, placed transversely across
the asophagus.. A similar condition of the
brain exists in the soft-bodied larvae of the

960

INSECTA.

Lamellicornes, as shown in Swammerdam's
drawing of Oryctes,* and Burmeister has
delineated a like condition in the larva of
Calandra Sommeri.\ We have before seen
(fig- 405) that such is also the case in the brain
of Timarcha. From this it would appear that
the cerebral ganglia are the parts of the nervous
system last perfected in the larva, while it is
interesting to observe that the reverse is the case
as respects the terminal ganglion; that part,
as correctly remarked by Professor Grant,}
being the first to advance forwards and become
united to the penultimate ganglion, to form
the great caudal mass, at an early period of the
larva. This is evident in the Timarcha, in
which the eleventh and twelfth ganglia have
coalesced into a single mass, while the cerebral
ganglia only just meet above the oesophagus.
But this is not the case in the perfect insect,
(jig. 408;) in which the cerebral ganglia (A)

Fig. 408.

Nervous system of perfect state of Timarcha tetie-
bricosa.

A, cerebral mass or brain j B, optic nerves; C,
origin of sympathetic.

have become greatly enlarged, united together,
and represent a distinct brain, from which pro-
ceed the nerves of sense, and united by long
crura to the medulla oblongata (1), from which
are given off as before the nerves of the organs

* Biblia Nat. tab. xviii. fig. 1.

t Zur Naturgeschichtc der Gattung Calandra,
fig. 13, Berlin, 1837.

t Phil. Trans. 1832, part ii. p. 384. Outlines of
Comparative Anatomy, p. 193.

of manducatlon. The cords are enlarged, as
also are the three ganglia of the thorax and
their nerves, and a coalescence has taken place
between the fourth, fifth, and sixth ganglia,
their intervening cords being entirely obliterated,
and the nerves aggregated together are now
derived from one mass, the great meta-thoracic
ganglion, the last part of the nervous system in
the thorax. A similar change haS also taken
place in the remaining part of the cord and
ganglia, which now forms the abdominal por-
tion. The cord between each of the ganglia
has been shortened, and the tenth, eleventh,
and twelfth are united and form the caudal
mass, which is situated about half way across
the abdomen. Such are the changes that take
place in the nervous system of an inferior type
of Coleoptera; in the higher forms, as in the
Melolontliida, the series of approximated
ganglia does not extend beyond the middle of
the meta-thorax, the cords being terminated by
a kind of cauda equina, all the nerves that go
to the abdomen are aggregated together and
extended into that region over the post-furca.
A similar structure, but in a less complete form,
exists in the Dytiscida, in which, as in the
Hydaticus cinereus, a short cord is found with
seven constrictions upon it, corresponding to
that number of ganglia which probably
existed in the larva state, but have nearly dis-
appeared during the metamorphoses. But that
this concentrated form of the nervous system is
not necessarily connected with high develop-
ment of other parts of the body is further
shown in the common Earwig, Forficula auri-
cularia, in which there are ten distinct sub-

Fig. 409.

Nervous system of the Earwig ( Forficula auricularia).

oesophageal ganglia. The first, or medulla, is
large and closely connected by very short crura
with the brain, there being only a narrow

INSECTA.

951

passage between the two for the esophagus.
Each segment of the thorax contains a ganglion,
the meta-thoracic one, which gives nerves to
the wings, being the largest. In the abdominal
portion of the cord, which extends as far as
the penultimate segment, there are six double
ganglia very distinct from each other. This is
exactly the number found by us in the same
portion of cord in the Carabidte, although,
according to Burmeister, there are only five.
Thus, then, in the Forftcutiefo, in which there
is the most extensive motion of the segments
of the abdomen, there is the same number of
ganglia as in the Carabida, in which most
of the abdominal segments are anchylosed
together and immovable, as in the Lamelli-
cornes, in which the whole of the cord is
situated within the region of the thorax. In
the oil-beetles, as in Proscarabaus vulgaris,
there are as usual three thoracic ganglia, the
largest being the meta-thoracic, although the
proper wings, and scarcely even the elytra, do not
exist. In the abdominal region there are five
ganglia, but smaller than those of the thorax,
although it is stated by Burmeister* that these
ganglia of the thorax are larger than those of
the abdomen when perfect organs of flight are
developed, but smaller when they are absent.
So far as our own observations have extended,
we have invariably found the thoracic ganglia
larger than the abdominal, whether organs
of flight exist or not, a condition that might
naturally be expected whether the ganglia be
connected with the production of nervous energy
in the parts, or be only the centres of sensation.
In the full-grown larva of this insect, of which
•we have examined a considerable number, but
which at present appears to be scarcely if at all
known to naturalists, we have found twelve per-
fectly distinct sub-oesophageal ganglia. Of these
the fifth was the largest and separated from the
fourth only by a very short cord, as were also
the eleventh and twelfth, besides which the
twelfth was larger than the eleventh, and ap-
peared as if formed at an early period of two
approximated ganglia. That in the earliest
state of this insect there are thirteen sub-
resophageal ganglia seems highly probable. On
watching the changes that take place it is found
that this d ouble terminal ganglion becomes united
to the eleventh, and that a similar union takes
place between the fourth, fifth, and sixth, so
that only five separate abdominal ganglia exist
in the perfect insect. In the Forficula, which
does not undergo a perfect metamorphosis, a
similar change appears to take place at a much
earlier period, the terminal ganglion being dis-
tinctly formed of two masses, and the ganglion
of the meta-thorax or wing-bearing segment of
three. A similar change appears also to occur
in the Staphylinidtf . In Creophilus maxillosus
(Jig. 341), in which the abdominal segments are
as freely moveable as in the Earwig, but which
undergoes a more complete metamorphosis,
there are nine sub-oasophageal ganglia, only
the last three of which are abdominal, the last
five segments being entirely without ganglia.

* Op. cit. p. 281.

There is exactly the same form and position of
the nervous system in the common species,
Goerius olens. On- comparing these circum-
stances it is found that a much smaller number
of ganglia in general exists in those perfect
insects which have undergone a complete meta-
morphosis than in the larva state, and than in
those that scarcely change their form. In the
Gryllida:, Acrida viridissima (fg. 410), there is

Fig. 410.

Nervous system of Acrida viridissima.
A, brain; D, antennae; B, optic nerves ; d, man-
dibular nerve ; e, auxiliary connecting nerve ;
g, nerve of prothoracic legs ; t, of second pair
of legs ; k, third pair ; a, tendon of flexor mus-
cle with its nerve accompanying it to its insertion
at extremity of the femur ; c, second head of the
same flexor muscle at the end of the tibia.

the same number of ganglia as in the Forficula,
and a similar difference in the size of the
thoracic ganglia. But in this insect there is
also a closer lateral approximation of the abdo-
minal cords, and a comparatively smaller size
and more elongated form of their ganglia,
evidently shewing a tendency to a more con-

952

INSECTA.

centrated structure, although the cords still
remain more distinct from each other than in
the higher forms of Coleoptera. In the AchetuLs,
of which the Mole-cricket affords us an exam-
ple, as combining amazing strength and activity
with apparently highly developed instinct, there
is a more complete general form of the nervous
system than in the Acrida. The ganglia of
the thorax are particularly large, but the ganglia
of the pro-thoracic segment, in which, and in
the enormous limbs, nearly the whole strength
of the insect, as we have before seen, is con-
centrated, does not equal in size the meta-
thoracic ganglion, which is nearly one-third
larger than either of the others, although the
wings unto which it is given, as well as to the
legs, are only of secondary importance as
organs of locomotion, and although a fifth and
much smaller ganglion is also attached to the
meta-thoracic. The cord of the thorax is also
large in proportion to the size of the ganglia.
In the abdomen the relative size of the cord
is less than in the Acrida, and there are only
three small oval ganglia in it besides the large
terminal one, so that the cord is extended
scarcely half way through the abdomen, and
yet the whole of the segments, and more
especially the posterior ones, are capable of
the most free and extensive motion. Thus,
then, although in these and other forms of
insects, particularly in the Hymenoptera, Lepi-
doptera, and Diptera, the ganglia are usually
aggregated together in certain segments, appa-
rently as a means of concentrating the energies
of the animal when one particular region of its
body is more actively employed than another,
the presence of ganglia in the different segments
is not more indispensable to the mobility than
to the sensibility of these parts to external im-
pressions, since the nerves that convey both
motion and sensation to them may be derived
from ganglia in distant segments, and yet the
freedom of motion be not less than when each
segment contains its own ganglion, and derives
its nerves immediately from it.

The structure of the cords in the perfect
insect is almost as distinct as in the larva,
although the whole of the parts have become
more opaque and closely connected together.
In some instances it is more strongly marked
than in others after the cord has remained for
some time in spirits of wine, which is necessary
before an examination of its structure is
attempted. In many of the Coleoptera the
motor column is seen passing in almost a direct
line over the ganglia of the sensitive, but the
transverse nerves are less easily detected, and
in many instances appear to have become
united with the other structures. We have,
however, seen what we regard as such in the
Gryllidte, and more distinctly in Gryllotalpa,
lying upon and above the motor column. In
some specimens we have not found them from
their being easily detached in those insects,
and, probably, removed during dissection. But
in these families we have always found the
motor column strongly marked, particularly
while passing over the ganglia of the thorax.
In the Carabide (Jig. 411) the course of the

motor column (6) is distinctly indicated as it
passes over the surface of a ganglion (a) by a

Fig. 411.

A portion of the gangliated abdominal cord of Carabua
monilis.

a, a ganglion of the external or sensitive column ;
b, the upper or motor column; c, a ganglion of
the transverse nerves.

longitudinal sulcus. Just as it is entering upon
and also as it is leaving the surface of the
ganglion, the motor column gives off a minute
branch to join with the large branch from the
ganglion of the sensitive column, and with it
form a compound nerve. At a part of the
cord corresponding to the anterior margin of
each ganglion, lying upon and attached to the
motor column on each side, is a minute gangli-
form mass (c), which we regard as the analogue
of the plexus of the transverse nerves. It is of
an obtusely angulated shape, and is attached
to the motor column by a minute filament from
its base on either side, and which passes out-
wards in the direction of the anterior pair of
nerves. From its upper part in the median
line extends another filament, the course of
which we have not been able to follow. In
Lucanus cervus the motor column is slightly
elevated while passing over the ganglia, and at
the anterior margin of each gives off a filament
to join with the nerve from that part of the
cord. We have sometimes observed attached
to the motor column, just as it had passed over
the meta-thoracic ganglion, on each side a
little gangliform mass, which may possibly be
part of a series of nerves like those on the cord
in the Carabus. In the aculeate Hymenoptera,
in which the ganglia of the thorax are large, the
motor column is readily observed, but in some
of the Terebrantia, as in the Turnip-fly, Athalia
centifolia, when the cord is examined by a
strong light, the motor column is most distinctly
seen both on the ganglia of the thorax and
abdomen, and in this insect exhibits an appear-
ance which we have not observed in any other.
This is a slight increase in the diameter of the
column when it has passed about half-way
over a ganglion, and a decrease to its original
size when leaving it. Two filaments appear to
be given off from the column to join the nerve
from the ganglion, one as usual at the anterior
margin of the ganglion, and the other, which
appears to be the analogue of the transverse
nerves, united to the motor column when
about half-way over the ganglion. This en-
largement of the motor column is greatest
where it is passing over the thoracic ganglion,
but is best seen on the abdominal ones.
This fact has appeared particularly interesting

INSECTA.

953

to us, as we have elsewhere remarked,* from
its seeming to be analogous to similar enlarge-
ments on those parts of the spinal cord in man
and other vertebrata, from which proceed the
nerves to the arms and lower extremities of the
body, and corresponds to the apparent greater
necessity for accumulations of nervous matter at
those parts of the cord. In Lepidoptera the cord
is less easily examined in the perfect than in the
larva state owing to its increased opacity, but the
transverse nerves are not only distinct but have
been removed forwards and now pass off on
either side midway between the ganglia.

The brain and its nerves do not acquire their
full development until near the termination of
the pupa state. The supra-oesophageal ganglia
(A) of the larva, which, for convenience of
description, we have called after Burmeister
the cerebrum, are in reality the analogues of
the corpora quadrigemina, and the first sub-
oesophageal of the medulla oblongata. Bur-
meister has designated this the cerebellum, but
of that part of the brain in vertebrata we believe
there is no analogue in any of the invertebrata.
Instead of the cerebral mass being divided into
two ganglia, as in the larva, it has now
(Jig. 412, A) acquired a compact form; it is

Fig. 412.

A, brain of Timarcha tenebricosa ; B, optic nerves;

C, origin of the sympathetic and the crura ;

D, the medulla oblongata ; b, the vagus or
visceral nerve passing back from its ganglion ;
e, lateral nerves from the ganglion.

convex on its upper surface with a slight
depression in the middle line, and concave on
its under, to adapt it to the form of the oesopha-
gus, across which it is placed. At its sides it
gives off the large optic nerves (B), which are
almost equal to it in diameter. They pass
directly outwards and are usually swollen into
the form of an oblong ganglion, but are again
constricted before they arrive at the optic fora-
men, through which they pass and are imme-
diately expanded into an immense number of
fine filaments for the complicated organ of
vision. There are enlargments upon these
nerves at their base even in the larva state
(fig- 405). From the most superior portion of
the cerebrum originate the nerves of the ocelli.
They vary in number from one to three, and

* Prize Essay, p. 11.

are little pyramidal elevations situated on each
lobe, as seen in Acrida (Jig. 410), posteriorly
to the antennal nerves (D). They are each
covered by a dark choroid, and in other respects
are distinct nerves of vision. When three exist,
as in Hymenoptera, the third is situated in the
middle line between the others, and appears to
be derived in part from each lobe, so that in
this ocellus the vision of both sides of the brain
is combined. In the Vespada, however, accord-
ing to Burmeister, the three ocelli originate
from a single foot-stalk, and not separately, as
in the Apid<e. On its anterior surface the
cerebrum gives off the antennal nerves. These
also, in many instances, have a ganglionic
enlargement at their base, as is well seen in
some of the Ichnenmonida and other Hymen-
optera, and as shown by Straus Durckheim
in Melolontha. The antennal nerves vary in
position, being sometimes near the middle line
and at others close to the base of the optic,
but in every instance anterior to them. At its
anterior and inferior surface the cerebrum pro-
duces the two remaining pairs of nerves. The
most external, the glosso-pharyngeal, unites
with its fellow of the opposite side to surround
the oesophagus, as in the larva. It is seen very
distinctly in the pupa state (fig. 415, f) of the
sphinx, and also in many perfect insects, as in
Acrida (fig. 410). It supplies the under-sur-
face of the throat and part of the oesophagus,
and a small branch is also given from its base
to the sides of the mouth. At its inner side
originates the recurrent or vagus nerve, which,
after passing a little forwards, ascends and
forms its ganglion on the upper surface of the
pharynx, and then passes backwards along the
oesophagus, as in the larva. In some insects,
as in Orthoptera, it originates from a portion
of the crura, as in Crustacea, but its course
and direction are always the same although
appearing to vary, as we shall presently show
when describing it as an organic nerve. The
sympathetic originates, as in the larva, from
the posterior part of the brain. One circum-
stance that particularly distinguishes the brain
from the other ganglia is its more uniform
opacity and greater softness, and disposition to
deliquesce when exposed for a short time to
the air. It is usually larger than most of the
other ganglia, excepting perhaps the meso-
thoracic. In Hymenoptera it is larger than in
other insects, a curious circumstance this if it
may be supposed to have any reference to the
comparative instinct of different species. In
Diptera and Orthoptera it is also of great size.
We were once desirous of knowing whether it
contains any cavities or ventricles, but after the
most careful search we have been unable to
detect any. It is an almost homogeneous mass,
penetrated throughout its whole substance by
minute air-vessels, which ramify within it and
also in the substance of the optic nerve. This
is one of the circumstances that lead us to
suspect, as formerly suggested by Dr. Kidd in
his anatomy of the Mole-cricket,* that the
course of the blood in the different structures

» Phil. Trans. 1826.

954

INSECTA.

always accompanies that of the trachea. The
crura vary much in length in different species.
In Neuroptera, Hymenoptera, Lepidoptera,
Diptera, and Homoptera they are short and
thick, and form with the medulla a thick collar,
through which the oesophagus passes as a narrow
tube; but in the Gryllida (fig. 410), and
more particularly in the Lticanidtf (fig- 413),
they are excessively elongated, and they are
also of great length in the Timarcha. The
medulla oblongata varies much in size ; in some,
as in the Lepidoptera, it is as large as one of
the lobes of the cerebrum, while in others it is
scarcely thicker than the crura. It is always
largest where large nerves are required for the
parts of the mouth, which in all cases are
derived from it. In this respect there is a striking
analogy between it and the medulla oblongata
of vertebrata. The anterior pair of nerves from
this part are given to the labium and lingua,
while the two next pairs are given to the man-
dibles and maxilla. In the distribution of these
nerves there is great similitude to that of the
fifth pair in the higher animals. In the larva
state these nerves are always distinct from each
other, but in the perfect they are often united
at their base into one trunk. This is the case
in the Timarcha and Gryllida. The anterior
pair is the largest in mandibulated insects,
and supplies the powerful mandibles, while
the posterior pair is given to the maxilla. The
union of these nerves at their base is interesting
from the circumstance that during manducation
a consentaneous movement of these parts is
required, since, while the mandibles are em-
ployed in chewing, the maxillae are also em-
ployed in turning and assisting to pass the food
into the pharynx. In the Sphinx ligustri, and
other Lepidoptera, the chief portion of the man-
dibular nerve has disappeared in the perfect
state, in consequence of the atrophy which has
taken place in the mandibles during the trans-
formations ; but one branch of the nerve which
exists in the larva state appears to have become
approximated to the maxillary nerve, which is
now greatly elongated and given to the pro-
boscis, the representative of the maxillae of
the larva. The branch that appears to have
belonged to the mandibular nerve is extended
along the concave or inner side of each half of
the proboscis, where the sense of taste may
justly be suspected to reside, and is traceable
very nearly to the extremity of the organ, where
the papillae we formerly noticed are situated,
and in the direction of which this nerve is
extended. From this we believe it to be
analogous in function to the gustatory portion
of the fifth nerve in vertebrata. In Lucanus
cervus the mandibular nerve is of great length,
and is so extensively developed as to afford
almost a proof of the elongation of nerves
during the metamorphoses of the insect. We
have traced this nerve from its origin (Jig.
413, c) into the base of the mandible, which it
enters a little external to the insertion of the
flexor muscles, where it is divided into three
trunks, the inner one of which we have traced
very nearly as far as the apex of the mandible.
The other two are situated more externally.

Nervous system of Lucanus cervus.

A, the brain ; B, optic nerves ; C, sympathetic ;
D, antennal nerves; a, ganglion of the vagus
nerve ; b, the nerve ; i, its division on the oeso-
phagus ; d, nerve to the first pair of legs ; /,
nerve to the wings, giving off at its base a small
nerve to the elytra ; g, nerve to second pair of
legs ; k, to third pair ; I, abdominal cord and
ganglia.

INSECTA.

955

The most posterior one is given to the muscles
within the head, and the other passes along the
outward part of the interior of the mandible to
its apex. The medulla oblongata with the con-
tinuation of the nervous cord in all Coleoptera
passes under the bony arch or tentorium at the
base of the skull, protected on both sides, as
in Melolonthu,* Dyticus, and Hydrous, by the
lamina posteriores, which inclose it, as in a
canal, distinct from the oesophagus, that passes
along above it, and from which it is separated
by a fine fibrous membrane. The crura and
the base of the cerebrum rest upon and are
partly protected on each side by the lamina
squamosa, which thus, as it were, form a kind
of internal skeleton for the protection of the
soft part. The optic nerves at their base rest
upon the laminae in their course to the eye,
and extend as far outwards as the lamina
orbitales through the foramen in which they
pass, and are immediately expanded into an
immense number of filaments which form part
of the organ of vision, as we shall presently
describe. The whole of the cerebrum is loosely
covered by a fine transparent membrane that is
continuous with the fibrous membrane that
covers the cord. In some instances, as in the
Bombus terrestris, it is very distinct, and in
others, as shown by Burmeister, is studded
with minute opaque rounded elevations, arranged
in the form of squares. It appears to be
reflected along the course of the optic nerves,
and to be continuous in part with the margins
of the lamina squamosa, and separates the
brain from the muscles, by which it is on almost
every side inclosed. In Lucanus cervus, instead
of the medulla passing under a simple arch
or tentorium, the laminae laterales are approxi-
mated and form a double ring (Jig. 388,^,
through the inferior of which, as through the
ring of a vertebra, the nervous cord passes in
its course to the prothorax. In the Orthoptera,
as in Blatta Americana and Gryllotalpa, we
have seen the same structure, but in these the
ring is lengthened and forms a more distinct
canal. In the Hymenoptera, as in the hornet
and humble-bee, the form of the part is exactly
the same, and the cord passes through a short
bony ring in its passage to the thorax. There
is a somewhat similar structure in Lepidoptera
as in Sphinx ligustri, only that it is much less
complete, the arch being simply a bar extended
across the occipital foramen and dividing it
into two, through the lower one of which the
cord passes, and also on each side of it the
flexor muscles of the head. A like form exists
in the Homoptera, but much less perfect.

The cord and nerves of the thorax, which
are usually much larger than those of the
abdomen, we regard as the proper cerebro-
spinal system, and the abdominal portion as
the caudal. This is the view taken of these
parts by Burmeister, with whose opinion we
perfectly coincide. The prothoracic ganglion
is situated immediately before the ante-furca,
between which the cord passes to the meta-
thorax, when it forms a great ganglion anterior

* Straus, Considerat. &c.

to and beneath the medifurca, and then passes
onwards over the post-furca to the abdomen.
In the Lamellicornes and others in which the
cord terminates in the thorax, and the nerves
radiate from thence into the abdomen as a
caudu equina, they pass over the post-furca in a
bundle, and do not separate until they enter
the latter region. In the Gryllidae, in which
most of the segments are equally developed, and
there are three large thoracic ganglia, the meta-
thoracic one is situated in the middle of the
segment, and the succeeding or fourth sub-
CEsophageal ganglion on the rudimentary post-
furca. In the Hymenoptera, in which there
are but two ganglia in the thorax, the anterior
and smaller one is situated at the margin of the
metathorax, and the great ganglion at the
posterior, and the cord continued from it passes
through a strong bony canal or ring in the
medifurca, somewhat resembling that which
exists in the head, and then forms a smaller
ganglion before it enters the abdomen. In
the Hemiptera, in which it has been supposed
that there is only one ganglion ip the thoracic
region, the cord between the medulla and pro-
thoracic ganglion is exceedingly short, but is
protected in its passage through the elongated
neck, and then is developed into a large pro-
thoracic ganglion, the second ganglion being
situated in the middle of the raeso-thorax before
the medifurca. These parts are very distinct
in Nepa grandis. In the Lepidoptera, in which
the form of the thorax is more compact even
than in the Hymenoptera, the cord passes on
each side of the medifurca or part to which
the triangular muscles are attached, and is so
much enlarged as to appear almost like a por-
tion or continuation of each of the two great
ganglia situated before and behind it. The
cords and ganglia of the thorax are covered in
by a strong white membrane like those of the
head. In the Lepidoptera this is particularly
firm, so that the nervous system is not included
within the cavity of the thorax.

In the distribution of the nerves there are
some peculiarities. We have seen the auxil-
iary connecting nerves of Burmeister, as shown
by us formerly in the larva of the Sphinx*
(fig. 406), in many species. They exist be-
tween the cord and all the ganglia of the
thorax in the Gryllida (Jig. 410, e, A,) and
between the cord and the nerves to the wings
in Athalia centifblia and Panorpa communis.
We have seen them also in Oiceoptoma, Pro-
scarabaus, Creophilus, Lampyris, Forficula,
Blatta , and even in an imperfect form in
(Estrus, as well as in some of the Lepidoptera.
They are invariably connected with the nerves
to the wings, of which they form one portion,
and are far more frequently met with than
Burmeister appears to have supposed. We
formerlyf remarked on a peculiarity in the dis-
tribution of the thoracic nerves in the Sphinx,,
and the opinion then ventured with regard to
its nature we have since had reason to believe
was well founded. We have seen the auxiliary

* Phil. Trans. 1832, part ii. p. 387-8.
t Phil. Trans. 1834, part ii. p. 394.

956

INSECTA.

connecting nerves in the larva forming one por-
tion of the nerves for the future wing of the per-
fect insect. The nerves for both pairs of wings
are then derived separately from two portions of
cord and two distinct ganglia, and this is the
state in which they are also found soon after
the insect has changed to a pupa (jig. 414).

Fig. 414.

Pupa of Sphinx ligustri. (Newport, Phil Trans.)

The connecting nerves are then derived from
the cord (e, h\ and being joined each to the
first nerve from the next ganglion assist to form
the future alary nerves (f, »'). Now as the
change to the perfect insect proceeds, the second
ganglion (2) becomes approximated to the third
(5), which gradually disappears, and the cord
between it and the fourth becomes enlarged
and shortened, and passes on each side of the
insertion of the muscles in the centre of the
meso-thorax, the cord between the second and
third ganglion having also become obliterated,
so that there is then no ganglion intervening
between the origins of the two pairs of wings,
but only a portion of cord. The nerves for the
two pairs of wings then approach each other
diagonally, the anterior pair being directed
backwards, and the posterior forwards, until
they meet and form a plexus, their roots still
continuing distinct from each other; the root
of the anterior being derived from the cord

posterior to the united second and third gan-
glia, and that of the posterior from the cord
connected with the united fourth and fifth gan-
glia. After forming the plexus, the nerves are
again separated and given to the anterior and
posterior wings. The reason for this curious
union and complexity in the distribution of the
nerves to the wings is not at first very evident,
but on a little reflexion it is found to be regu-
lated by one of those beautiful provisions in
the animal economy by which the most perfect
harmony in the exercise of all the functions of
the body is preserved. The wings, the most
powerful and most constantly employed organs,
are not merely required to act with energy, but
in the most perfect unison with each other,
more especially in insects of long-continued
or rapid flight, and hence must be supplied
with power from the same centre, not merely
that of voluntary motion but also of sensation.
That this is the reason for this curious union of
the nerves for the wings seems apparent from
the circumstance that it exists in very many
tetrapterous insects of rapid or powerful flight,
as in the Apida and Ichneumonidtf, while in
others, even of the same order, as in Athalia
centifolitf, which is well known to fly heavily
and but a short distance, there is no such com-
bination. In the Scorpion-fly also, Panorpa
communis, it is absent, and the alary nerves
originate by double roots without forming
a plexus as in the larva of the Sphinx, while
the flight of the insect is sluggish and but of
short duration. Besides this it may be re-
marked that in many Coleoptera in which the
anterior wings or elytra are merely elevated and
nearly motionless during flight, the nerves are
derived separately from the cord, and proceed
to their destination without being first com-
bined in a plexus.

The cord and nerves of the abdomen, as before
stated, we regard merely as a cauda equina.
We have before explained the varieties in the
formation of the cord in different insects, and
need but further remark that in each instance
the cord in the abdomen, as in other parts, is
covered in by a strong fibrous membrane, which
separates it from the cavity of the abdomen.
In the Gryllida we have distinctly recognised
muscular fibres running transversely above the
cord from one side of the body to the other.
They have also been observed by Burmeister, who
supposes them to assist in the function of respi-
ration by contracting the segments, and thus
aiding in the act of expiration. We have seen
similar trans-muscles lying above the mem-
brane that binds down the nervous cord in the
abdomen of Bombus terrestris. The mem-
brane is continuous with that which covers the
cord in the thorax. A similar membrane was
formerly noticed by Lyonet in the Cossus,*
and subsequently by ourselves in the Sphinx.f
Between this membrane and the cord there is a

* Recherches sur 1'Anatomie et les Metamor-
phoses des differentes Especes d'Insectes, ouvrage
posthume de Pierre Lyonet. Paris, 1832, fig. 18,
p. 52.

t Phil. Trans. 1834, part ii. p. 395, pi. xiv.
fig. 9.

INSECTA.

957

vessel which we regard as connected with the
circulatory system, as we shall hereafter show.

As nerves of organic function, we have now
to consider those which are especially given to
the different internal organs, and not to the
voluntary muscles. Having already considered
the transverse nerves, which are distributed so

especially to the respiratory organs, as nerves of
mixed character, those which we regard more
especially under the above designation are the
sympathetic and the vagus or visceral nerves.
The sympathetic, or anterior lateral ganglia
(fig. 415, C), are situated two on each side of
the oesophagus behind the brain, and anterior

Fig. 415.

Brain and nerves of the head and first segment of a pupa of Sphinx ligustri.

A, brain; B, optic nerves; C, anterior lateral or sympathetic ganglia; D, antennal
nerves ; E, frontal ganglion of the recurrent or vagus nerve. (Newport, Phil. Trans.)

to the great muscles of the oesophagus and pha-
rynx. They are of considerable size, being
each about one-third as large as one-half of the
cerebrum, and they are connected with most of
the other nerves in the head. Thus, besides
their connexions (a) with the brain, one nerve
passes forwards beneath the optic nerves, and
joins with a minute lilament from the nerve to
the antennae, (g,) and also with one to the
mandibles, while another passing across the
oesophagus is united with the main trunk of the
visceral or vagus nerve (e), as it passes along
to the stomach, and another branch joins with
the first set of transverse nerves (A), while other
filaments passing outwards are distributed to
the muscles of the oesophagus and pharynx.
This latter fact, which we have most distinctly
ascertained in Meloe cicatricosus, a large species
well adapted both for an examination of this
and of the visceral nerve, is particularly inte-
resting from the circumstance that, after the
most careful examination, we could not find
any other nerve given to those muscles (fig-
416, C). We have observed a similar distri-
bution to the muscles of the oesophagus in Lu-
canus, and also in the Sphinx, so that from their
connexions we may justly conclude these gan-
glia to constitute at least a portion of the true
sympathetic system. From their relative situ-
ation they appear to be analogous to the supe-
rior cervical ganglia of the sympathetic in Yer-
tebrata. It is, however, an interesting fact, as

noticed by Burmeister,* that these ganglia ap-
pear to be largest in some of those insects in
which the recurrent nerve which we have de-
scribed as the vagus is least developed. Thus,
as shown by Muller, Brandt, and Burmeister,
these ganglia of the sympathetic system have
a large size in the Orthoptera, and, instead of
being traceable scarcely beyond the region of
the head, send off one or two branches which
run along the sides of the oesophagus to a great
distance, while the recurrent or vagus nerve,
after uniting with these ganglia behind the
brain, appears to terminate or be lost in the
nerves that originate from them. In Gri/llus
migratorius, Burmeister has shownf that after
the recurrent nerve has formed a minute gan-
glion just behind the brain, and united with
the first of these sympathetic ganglia, it ap-
pears to terminate, while the same ganglion
sends off posteriorly two branches, which run
along the upper surface of the oesophagus, where
the external one forms a small ganglion, and
that the second, or most external of these ante-
rior lateral ganglia, also sends a large nerve
backwards, at the side of the oesophagus, as far
as the crop, where it forms a ganglion and
sends off nerves, and at the hinder part of the
crop a second ganglion, from which nerves are
given to the coecal appendages of the alimen-

» Op. cit. p. 288.
t Id. pi. xxxi. fig. 6.

958

INSECTA.

tary canal. Muller* had previously shewn a
similar arrangement of these ganglia in Gryllo-
talpa vulgaris, and Brandt f has since further
elucidated the distribution of these structures
in the same insects. We have ourselves re-
cently found a somewhat similar distribution of
these nerves in one of the Coleoptera, Bupres-
tis chrysis, in which the first of the anterior
lateral ganglia, on each side, besides its con-
nexion with the brain, gives off three distinct
nerves, one of which passes outwards to the
muscles of the oesophagus and pharynx, and
another inwards to unite with the great trunk
of the recurrent nerve, while the third passes
backwards for a short distance, and then forms
the second of the lateral ganglia, from which,
in like manner also, proceed three other nerves.
The first of these passes outwards to the sides
of the oesophagus, and the second inwards to
join a large ganglion formed at the extremity
of the recurrent nerve, while the third branch
is of considerable length and traceable for a
great distance along the sides of the oesophagus.
From the ganglion at the termination of the
recurrent nerve, and which most certainly be-
longs to this trunk, are also given off two nerves,
which are soon again divided, and distributed
along the posterior part of the oesophagus.
From these connexions, and the relative size
of the parts, it still appears to us that although
the sympathetic and recurrent nerves are most
intimately connected, and appear in certain
instances almost to supply the place of each
other, there is reason for still considering them
as distinct, and for describing the latter, as we
formerly designated it,J as the vagus.

The vagus, or visceral nerve of Professor
Miiller, after arising, as in the larva, from the
anterior part of the base of the cerebrum, and
forming a ganglion on the upper surface of the
pharynx, always passes backwards beneath the
brain, along the middle line of the oesophagus.
We shall first describe its course in Lepidopte-
rous insects, and point out what we conceive to
be its analogies to the vagus of vertebrata. In
the Sphinx it originates in the perfect insect, as
in the larva, from the lowest part of the anterior
surface of the brain by two roots, one on each
side, which we regard as analogous to the two
vagi in the higher animals. Each root gives off
from its base a small branch to the sides of the
mouth, after which the two roots ascend, and
meeting above the pharynx, form the frontal
ganglion, from the anterior surface of which a
few nerves are given to the mouth and palate,
and also to the bifurcation of the dorsal vessel,
which, after having passed along the oesopha-
gus and beneath the brain, is divided in front of
the brain into several branches. The frontal
ganglion at the junction of these roots of the
vagus we regard as analogous to the enlarge-
ment on the vagus nerve in vertebrata after it
has passed out of the skull by the foramen la-
cerum posterius. From the ganglion thus
formed by the approximation of the two roots,
a single trunk passes backwards along the me-

* Nova Acta Curios. Nat. vol. xiv.
t Annal. des Sciences Natur. torn. v.
t Phil. Trans. 1832.

dian line, lying upon the oesophagus and be-
neath the dorsal vessel, and giving to both se-
veral branches in its course. When arrived at
the dilatation of the oesophagus, the air-bag or
crop, it first distributes a few filaments to that
part, and then divides into two primary
branches, which run along the sides of the
stomach, and are again subdivided and distri-
buted to it. Behind the brain, the vagus in the
Sphinx receives but one branch of communica-
tion on each side from the sympathetic ganglia,
which connexions appear to be analogous to
those between the vagus and sympathetic in
vertebrata. In passing along the median line
of the oesophagus, the single vagus in insects
is in close relation with the anterior or aortal
portion of the dorsal vessel, which may repre-
sent the two carotids of the higher animals
united, and thus its relation to these parts is
also precisely similar to that of the vagus, caro-
tids, and oesophagus in these animals. There is
a like analogy in its distribution to the anterior
part of the stomach, beyond the middle portion
of which it has never yet been traced. At its
point of division the single vagus nerve often
forms a very distinct ganglion, as in the Melb'e
(Jig. 416, i). This is the usual distribution in
a large majority of insects, more particularly
in the Lepidoptera, Coleoptera, Neuroptera,

Fig. 416.

Brain and vagus nerve of Meloe dcatricosus.

Hymenoptera, and in many of the Orthoptera.
In Lucanus cervus (Jig. 417), the nerve, conti-
nued backwards from the frontal ganglia (a), is
of large size until after it has passed beneath the
brain, and given off a minute branch on each
side to the dorsal vessel and oesophagus, after
which it becomes on a sudden much smaller,
and forms a second small ganglion, (e,) which
is connected on each side by a single
branch with the sympathetic ganglia (C,) which
have assumed an elongated form, and are
greatly enlarged. After this the vagus nerve
is ' continued as a single trunk, (&,) until it

INSECTA.

959

has passed half-way along the oesophagus,
(jig- 428, H,) when it divides into two branches,
which pass on each side of the oesophagus as far
as the gizzard, (i,} where each forms a very
minute ganglion, from which are given a few
filaments to the substance of the gizzard.

Fig. 417.

Brain, sympathetic ganglia, and vagus nerve of
Lucanus cervus.

Each nerve thus passes on to the stomach, (K,)
and we have succeeded in tracing it about half-way
along that organ, when it can be followed no far-
ther, being lost by minute subdivisions. As con-
nected also with the vagus nerve both in func-
tion and by analogy of distribution, is the nerve
which we noticed so particularly in the larva,
the glosso-pharyngeal, (fig. 418, F,) which is
remarkably distinct in Lucanus, and as in the
larva gives branches to the under-surface of the
esophagus. It is remarkable, also, that in this
insect each root of the vagus arises from a
ganglion on each side, situated below the cere-
bral lobes, but closely connected to them, and
from which ganglion the antennal nerves (D) ori-
ginate, and a third nerve, which is directed
backwards ajnong the muscles, but the course

of which we have not yet traced, but which
probably is a compound nerve ; it appears to be
formed in part by the ganglion, (E,) and partly by
a portion of the cerebrum, which is united to it.

Fig. 418.

Under-surface of brain, S^c, of Lucanm cermu.

The form which the frontal ganglion usually
assumes is nearly triangular, but in some in-
stances, as in Carabus monilis, it is elongated,
oval, lying transversely across the pharynx, but
in almost all the insects we have examined, ex-
cepting the Buprestida and some of the Or-
thoptera both in the larva and pupa state, as
in Tirnarcha, Meloe, Anthophora, and Bombus,
whatever be its form, the single nerve continued
from it has more resembled in its distributions
and relations the vagus than the sympathetic.
These are the reasons for our continuing to de-
scribe it as the former rather than as the latter
of these nerves. The fact, however, of its dis-
position to form ganglia in its course appears,
indeed, as observed by Professor Miiller,* to
assimilate it most in character with the sympa-
thetic ; but we conceive this fact to be satisfac-
torily explained by the anatomy of these nerves
in Buprestis, in which the middle or recurrent
nerve, although exceedingly short, is very
large, and is terminated by a ganglion, as in
the Gryllida, and from which, in Buprestis,
two small nerves are continued along the eso-
phagus, while the corresponding nerves in
Gryllus have become approximated to those
from the lateral ganglia, and assist to form the
long gangliated nerve at the side of the oesopha-
gus. The functions of the vagus and sympa-
thetic in insects would thus appear to be nearly
similar, and that, as is sometimes the case with
these nerves in vertebrata, as we have seen, for
example, in the neck of the calf, the two become
often closely approximated together, as noticed
also by Professor Miiller, in the Myxinoid
Fishes, in which the vagus and sympathetic
form only one nerve, the chief portion of which
is the vagus, and which is extended to the anus.

* Muller's Archiv, No. v. 1837, Jahresbresbt, p.
Ixxxv. to viii.

960

INSECTA.

Organs of vision. — The eyes of Insects are of
two kinds, simple and compound, and have
been attentively examined by Professor Miiller,
Straus Durckheim, Duges, and others, from
whose admirable investigations we shall chiefly
derive the following description. The large
convex cornese which cover the external surface
of the head are divided, as we have seen, into
an immense number of facets, generally of an
hexagonal shape, or in very rare instances
somewhat quadrangular. Each facet, (Jig.
419, B,) or as it has sometimes been called,
corneule, is the proper cornea of a distinct eye,
and is perfectly transparent. It is somewhat
broader at its base or external surface (B, c)

Fig. 419.
C

A, section of the eye of Melolontha (Straus).
B, section of eye of Libellula (Muller). C, sec-
tion of do. (Duges). b, the external convex
surfaces of the facet or corneule c, c, c; d, base
of the corneules ; a, the anterior chamber be-
tween the corneule and iris ; e, pupillary aper-
ture in the iris, formed by the reflexion inwards of
the choroid ; f, the cones filled with the vitreous
humour ; g, the nerve ; h, the choroid surround-
ing the fibres of the optic nerve.

than at its internal, (rf,) and each one is separated
from those by which it is surrounded by the inter-
position of a layer of dark-coloured pigment, so
that therays of light can pass through it only in a
direction converging to its centre. In some in-
stances, as in Lepidoptera, it is convex both on
its external and internal surface, or lens-like,
but in general is nearly plane. In the Libellu-
lina, according to Duges, (c,) it is convex exter-
nally, and slightly concave internally, and it va-
ries considerably in thickness in different in-
sects, and in different facets in the same
compound cornea. Immediately behind each

corneule is a layer of dark-coloured pigment,
(//,) which is believed to be continuous with the
delicate pigment that is interposed between the
corneae. It covers the whole of the inner surface
of the cornea, excepting only in the centre,
where it is perforated by a minute hole or pupil-
lary aperture, (e,) to admit the rays of light that
have passed through the cornea. Between this
pigment, which is the curtain or iris of the eye,
and the end of the cornea, Duges found a
space, («,) filled with an aqueous humour. Be-
hind the iris of each cornea is a little cone-
shaped transparent body, (a/j) with its apex
directed backwards in the axis of the eye. It is
filled with a perfectly transparent tenaceous
fluid, the vitreous humour of the eye,into which
the rays of light received through the cornea
and iris are admitted, to fall upon the retina,
or termination of the nerve, (g,) at the apex of
the cone. The length of the cone differs greatly
in different insects. It is shortest in the Dip-
tera, and scarcely exceeds its breadth. In the
Coleoptera and Lepidoptera it is five or six
times longer than it is broad, and perhaps even
exceeds this in some of the Libellulina. The
apex of each cone is received upon the extremity
of one of the many thousand of fibres (g)
which we described as radiating from the bulb
of the nerve, immediately after it has passed
through the optic foramen. The choroid of
dark pigment that forms the iris (h) is conti-
nued backwards over the surface of the cone
and optic fibre to the bulb of the optic nerve,
thus completely insulating every individual
cone and fibre from those by which they are
surrounded. It is in the spaces thus occupied
by the choroid that the tracheal vessels and cir-
culatory passages ramify, so that the choroid in
the eyes of insects, as in those of the verte-
brata, is the proper vascular structure of the
organ. It is subject to much variety of colour
in different insects, being in some nearly black,
in others dark blue, violet, green, purple,
brown, or yellow. In some there are two or
three layers of pigment of different colours.
The usual arrangement of these is first a dark
coloured portion near the bulb of the optic
nerve, then a lighter colour, and lastly, again, a
darker near the corneae. According to Duges,
the base of the cone is rounded where it is co-
vered by the iris, but Miiller states that this is
the case only when the cornea is devoid of
facets or corneules, and is perfectly smooth.
According to the same authority, the pupillary
aperture is most distinct when the cones are
short, as in Diptera. This aperture was disco-
vered by Muller, and also the nature of the
cones, which had been thought by Straus-
Durckheim to be expanded terminations of the
optic fibres. We have seen the iris and pu-
pillary aperture very distinctly in the eye of
Pontia brassicce, the white cabbage butterfly,
and also in Sphinx lignstri and Nepa grandis.
In the two latter instances it is of a dark brown,
or nearly black, and is particularly large in
Nepa. In Pontia it is yellow, in the centre
of which the pupil exhibits a glassy brightness.
The manner in which the extremity of the ner-
vous fibre is connected with the apex of the
cone has recently been investigated by Professor

INSECTA.

961

Wagner, who has found that the fibre is pro-
longed as a shealh over the sides of the cone, of
which it is supposed to form a part. In this
manner, each of the thousands of coraeules or
facets that form the compound eye, transmits
impressions from without inwards to the optic
nerve and brain, the perception of each being
confined to that of the object immediately
before it, or in a line with its axis of vision.
On the exterior surface, between each cornea,
there are often some very fine hairs, as on die
cornea of the bee, which Burrneister likens to
eyelashes, and thinks that they assist to con-
fine the field of vision, as well as protect the
cornea. This is the usual structure of the eye.
In sMelolontha, Straus-Durckheim describes
the filament of the optic nerve as passing
through a second or comttion choroid, and as
afterwards uniting to form a general retina,
which is connected with the optic nerve by
means of short thick columns. The use he
assigns to this structure is that of intercepting
the impressions of light, which might otherwise
be too powerful.

The ocelli, or simple eyes of insects, re-
semble those of Arachmdans,* in being
formed of a very convex, smooth, single cornea,
beneath which is a spherical crystalline lens,
resting upon the plano-convex surface of
the expanded vitreous humour, the analogue
of the transparent cones of the compound eyes.
The vitreous humour, as in Arachnidans, is
more convex on its posterior or under surface,
and is contained in the expanded retina at the
termination of the optic tubercle, upon which
each ocellus is situated, the exterior surface of
the retina being covered by a dark pigmentous
membrane, the proper choroid, which is re-
flected inwards upon the anterior portion of the
vitreous humour, to form the iris and pupillary
aperture. Dialler, who discovered this ^struc-
ture in the stemmata of insects as well as
Arachnidans, concludes that the function of
the simple eyes is confined exclusively to the
perception of near objects, and that of the
compound eyes to more distant ones, and has
given many facts in illustration of this opinion,
and which shew that in many instances, parti-
cularly in the Orthoptera, the ocelli are so
placed as to render it almost impossible that
they can be used except in viewing near ob-
jects. In all insects that undergo a true me-
tamorphosis ocelli constitute the only organs
of vision in the larva state. They vary in
number in different species; thus in the active
larvae of Hymenoptera, as in Athalia, there are
only two, one on each side of the head ; this is
also the number in some of the carnivorous
Coleoptera. But in others there are six on
each side, as in Dyticus, and the same number
is found in most of the Lepidoptera. We have
recently detected what we believe to be organs
of vision in a Dipterous larva, CEstrus avis, (Jig.
360,) which resides in the frontal sinuses of the
sheep, into which, probably, a small amount of
light may enter through the nostrils. These
consist of two brown spots on each side of the

* See ARACHNIDA, vol. i» fig. 94.

VOL. II.

head, (h 2,) placed al a little distance from each
other, immediately beneath a convex and very
transparent part of the tegument, which resem-
bles a true cornea. This is the most simple
form of eye we have yet met with in insects,
and seems to be merely for the perception of
light, like die eyes of the Medusa: discovered
by Ehrenberg, but perhaps more organized, as
the spots observed appear to be a choroid,
which is seen to descend until it is lost in the
substance of the part. No compound eyes
exist in any larva that undergoes a complete
metamorphosis. In those which undergo an
incomplete one, as in the Orthoptera, the
facets of the eye are larger and more convex
than in the perfect state, and the true ocelli
which exist in the perfect state are not deve-
loped. In the larva and pupa of Reduvius
personatus there is an aggregation of simple
eyes, like those of Myriapoda, very much
larger and more convex than the facets of the
compound eye of the perfect insect. Simple
eyes exist in the perfect state in the Hymenop-
tera, Orthoptera, Hemiptera, Neuroptera, Tri-
choptera, Homoptera, and in some of the Lepi-
doptera and Homaloptera, and in a very few
instances in the Coleoptera.

Organ of hearing. — Every naturalist who has
at all attended to the consideration of the faculty
of hearing in insects, is doubtless convinced
that these little creatures are not merely affected
by sounds, but that hearing constitutes one of
their chief senses; yet it is hitherto undecided
what organ or part of the animal is the seat of
this function. We have above stated our opinion,
(p. 892,) with many others, that it resides in the
antennae, which, if this be not confirmed, is at
any rate supported by the experiments hitherto
made upon these organs, and also by their
structure and the manner in which they are
employed by the insect. The nerves distributed
to the antennae have often a ganglion at their
base, and are divided into many branches almost
immediately after they have entered the organ,
so that at present no difference has been detected
between the distribution of the nerves to these
parts and those to other structures. They cer-
tainly exhibit no bulbed extremity like the audi-
tory nerves of the higher animals, while the
manner in which the antennae are employed
by many insects has induced some observers to
believe that they are simply organs of touch.
This cannot be their primary function, since, as
formerly remarked, they are too short to be
employed as tactile organs by many insects,
while their structure, we conceive, is in every
instance adapted for hearing or perceiving the
pulsations of the atmosphere.

Organs of touch. — The organs which appear
specially adapted to the exercise of this function
are the palpi, which derive their nerves, as
above shown, from the medulla oblongata.
These organs are employed in a similar manner
by all insects to touch the food. It is with
these that the insect, as it \\ere, Jeels about
when it is in search of nourishment, and hence
these may be regarded as the proper tactile
organs. It has sometimes been supposed that
they are also concerned in the function of taste,

3 R

962

INSE€TA.

but this opinion is not borne out by the physi-
cal condition of these parts, which, in almost
every instance, is unadapted for such purpose,
being covered by a hard bony exterior. In some
instances the extremities of the palpi are covered
with a soft bulb-like extremity, while in many
others which are known to perceive the quality of
food very quickly, they yet have the extremities
of the part covered with a hard imperforate
structure.

As to the seat of the organ of smell we are
quite as ignorant of it as of that of taste. Cuvier
and some others have imagined that the faculty
of smelling resides in the mucous lining of the
spiracles at the sides of the body, but ex-
periment has still left the question undecided.
From the few observations we have been able
to make on this subject we certainly have
been led to conclude that it is confined to
some part of the head, and not seated at the
different spiracles.

The development of the brain and nervous
cord during the metamorphoses exhibits some
of the most curious alterations of form that
take place in any structure. These changes
were first traced by Herold in the great
cabbage-butterfly, Pontia Brassicte, and sub-
sequently by the writer of the present article
in the privet hawk-moth, Sphinx ligustri*
and also in the nettle-butterfly, Vanessa urtica.
We have seen from the foregoing details, that
during the last period of the larva state, at
which time the insect has been most frequently
examined, certain changes of form have al-
ready taken place in different parts of the
cord, so that these changes of structure, which
at first appear to be effected so rapidly at a
certain period, have been for a long time in
progress. We have seen that, besides the la-
teral approximation of the cords, the first
change consists in an union of the eleventh and
twelfth ganglia, the latter one being carried
forwards ; and that, although a complete co-
alescence of these has sometimes taken place so
early as a day or two before the caterpillar casts
its last skin, yet even at that period the cere-
bral ganglia have scarcely become united above
the oesophagus. At a still earlier period, when
the larva has not yet cast its third skin, we have
found the eleventh ganglia perfectly distinct
from the twelfth, with a small intervening por-
tion of cord, and the cerebral ganglia scarcely
touching each other above the oesophagus, and
the distance, or extent of cord, between the
fourth and fifth ganglia much greater than at
the subsequent period when the insect is pre-
paring to change into the pupa state.

We had commenced our observations on
these changes in the nervous system on the
larva and pupa of the Sphinx, when it appeared
desirable also for various reasons to make
similar observations on an insect in which
these changes were commenced and completed
within a short and known period, and for that
purpose selected the commonest of our native
insects, the nettle-butterfly, Vanessa urtica,
which undergoes its changes within fourteen
days. The Sphinx remains in the pupa state

* Phil. Trans, pt. 2. 1832, 1834.

during the whole winter, by which we are
enabled to compare the same changes in an
insect in which they have taken place slowly
with those in another in which they have been
completed more rapidly, and the extent of
development at the completion of both is in-
variably found to be the same. In order to
observe these changes correctly, a large number
of the caterpillars was collected at the period
when they have ceased to feed, and are about
to suspend themselves to undergo their trans-
formation, and the moment was carefully
watched both when they suspended them-
selves preparatory to undergoing their meta-
morphoses, and also when they were in the act
of assuming the pupa state. By these means
a sufficient number of specimens was obtained,
and their periods of transformation accurately
known. Previously to commencing these ob-
servations on the nettle-butterfly, we had noticed
in the pupa of the Sphinx a very singular ap-
pearance at the base of each optic nerve, which
on close inspection was found to be a dark-
coloured membrane of an ovate form, from
which is developed the choroid of the future
eye. The existence of this spot is exceedingly
interesting as illustrating the manner in which
the complicated organ of vision in the perfect
insect is developed. This spot, which at first
appears like a dark gelatiniform deposit, con-
sists of five black tubercular elevations, having
the appearance of so many parts of a corru-
gated membrane, and exists before the larva
has changed into a pupa. We have never found
it absent in any insect that is about to change,
but have not observed it until the insect has
ceased to feed.

Two hours after the larva of Vanessa urticte
has suspended itself to undergo its transform-
ation, and in which state it remains from six to
eight, ten, or even twenty-four hours, according
to the strength of the individual and other cir-
cumstances, before it throws off its last larva
skin a considerable alteration has already taken
place in the body of the larva ; the cerebral
lobes are still distinct from each other, but are a
little altered in form, although not yet enlarged.
When viewed from above they exhibit a pear-
shaped appearance, the anterior part of the
lateral surface of each being elongated to give
origin to the antennal and optic nerves. At
the base of the latter, even at this early period,
the dark rudimentary choroid is very distinct.
The sub-03sophageal ganglion is enlarged to
nearly twice its original size, and the crura are
much enlarged and shortened, as well as the
cords that connect the second, third, fourth, and
fifth ganglia. The last two are separated only
by a short interval. The fifth, sixth, and seventh
ganglia are drawn closer together, the cords
between them disposed in an irregular ziz-zag
manner, and the longitudinal direction of the
ganglia is in consequence altered. The ganglia
from the seventh to the terminal one remain as
in the active larva.

By unremittingly watching a number of
larvae through all their preparatory stages, we
are enabled to judge within a very short period
when the transformation will take place. A
little while before the old skin is thrown off

INSECTA.

963

Immediately
after chanyitig

Half-an-kour *° a pupa.

before

clianging.

Fvll-groycn
lana.

(Newport, Ph. Trans.)
there is great excitement throughout the body of
the insect. About half-an-hour (Jig. 419, 2)
before this occurs the alary nerves and the
cerebral, second, third, fourth, and fifth ganglia
are slightly enlarged, and the medulla or first
sub-cesophageal ganglion very considerably. The
cords that extend between them diverge much
from each other, while those between the fiftri,
sixth, and seventh ganglia, are disposed in a more
zig-zag direction than in other parts of the body.

Immediately after the insect has entered the
pupa state (3), all the ganglia are brought
closer together in consequence of the cords
being disposed more irregularly than at any
other period, which has been occasioned by the
shortening that has taken place in every seg-
ment, by which the cords are rendered too long
to lie in a direct line. The cords which con-
nect the first five ganglia are slightly increased
in size, and the fourth and fifth and their inter-
vening cords, in which the first great changes
commence, are often nearer together, and have
become more united at this period of the trans-
formation, in some specimens, than in others
at five or six hours later. This is in accord-
ance with what we have observed in the Sphinx
ligustri, in which the precise period when the
union of ganglia takes place cannot positively
be ascertained in consequence of its differing
in different specimens according to the vigour
of the insect, or to the temperature of the
season at the time of changing.

One hour after (Jig. 421, 4) the transform-

Onekour after Twefce Itavrs. Eighteen hour*.

changing.

ation the cerebral ganglia are found to be more
closely united, the antennal nerves more dis-
tinct, and the optic nerves more enlarged at
their base. The fourth and fifth ganglia are
approaching each other, and the cords are en-
larged at their connexion with the latter, the
anterior part of which has become less dis-
tinct, and seems about to coalesce with them.
The distance between the remaining ganglia is
also reduced, and the investing membrane, or
exterior surface of the cord exhibits a corrugated
appearance as if in the act of becoming
shortened. We have seen in the account pre-
viously given of the nervous system in the
larva of the Sphinx, that besides the longi-
tudinal cords and ganglia, and the nerves dis-
tributed from them, there are also the trans-
verse nerves. There are like nerves in Papilio
wtiw, and which are distributed to the same
parts as in the Sphinx. They commence be-
hind the first sub-cesophageal ganglion or me-
dulla, where the first of them pass directly out-
wards in the course of the tracheae that come
from the first spiracle, and distribute and give
some branches to the surface of the medulla
and its nerves, and some also to the second
ganglion (d), while the main branch passes
along in the direction of the muscles of the
back part of the head. Behind the second
ganglion branches of tracheal vessels, and
also a nerve from the transverse plexus, are given
to the great alary nerve ( / ) that arises in this
insect singly from the cord between the second
and third ganglion, and not, as in the Sphinx,
one portion from the cord and another from the
ganglion posterior to it. From the cord be-
tween the third and fourth ganglion arises the
second alary nerve (i), which like the preceding
arises singly from the cord, but receives also a

1832.

3 R 2

964

INSECTA.

branch from the transverse nerves posterior to
the third ganglion. A plexus of these trans-
verse nerves exists, as in the Sphinx, anterior to
each ganglion (o, o), to the nerves of which
they give a single filament near their base, and
another when arrived near the spiracle, while
their main branches, as in the latter insect, are
distributed separately among the tracheae and
muscles. Those branches of transverse nerves
which pass off laterally from between the
fourth, fifth, sixth, and seventh ganglia, become
approximated to the nerves from those ganglia,
and in the development of the insect at this
period afford an example of the commence-
ment of the interesting fact of the formation of
nervous trunks by the approximation of many
fibres. The transverse nerves anterior to the fifth
ganglion (5, o) are those that first become united
to the moto-sensitive nerves from the gangliated
cord, and at this period of the transformation
the two are beginning to become united.

Seven hours after the insect has become
a pupa there is a greater enlargement of the
cerebral ganglia, optic nerves, and ganglia and
cords of the future thoracic segments. The
fourth and fifth have advanced closer together,
and the cord between them has become so
much shortened, enlarged in diameter, and ap-
proximated to its fellow, as to resemble in
shape a separate elongated ganglion, and
strongly to support the opinion formerly ad-
vanced by us* of the actual transmission for-
wards of the nervous matter within the in-
vesting membranes of the cord, rather han
that of its deposition and accumulation at
certain parts through the agency of the nutri-
tive or vascular system. At this period also all
the remaining ganglia have become slightly
enlarged, and the distance between the fifth and
sixth is much diminished, and the cords just
anterior to each ganglion are also slightly en-
larged and are disposed with less irregularity
than at a previous period. At this stage of the
transformation the transverse nerves (oo) also
are beginning to assume their temporary gan-
gl ionic appearance, and the terminal nerves
from the caudal ganglion are enlarged to sup-
ply the developing organs of generation.

At twelve hours (5) the fifth ganglion has
almost completely coalesced with the cord and
fourth, and has assumed an elongated trian-
gular appearance, and the transverse nerves,
which at seven hours were beginning to be
united to the nerves from this ganglion, have
now so completely joined them as almost en-
tirely to have disappeared, there being in
some instances only a triangular elevation upon
the gangliated cord, with a portion of nerve
passing outwards to indicate their previous
separation, thus affording a further proof of
the adhesion of contiguous parts, and of the
manner in which nervous trunks are formed.

At eighteen hours (6) the whole of the gan-
glia, cords, and nerves have become more en-
larged, particularly those of the wings, and the
transverse nerves, although continuing separate,
give filaments to the nerves from the gamglia,
and themselves exhibit at their point of di-
vision more the appearance of ganglia; while
the fourth and liiili <j;:ur>viu °f the cords have

now so completely united as to appear like an
irregular elongated mass. The abdominal por-
tion of the cord is now extended in a more
direct line in the body, and anterior to each
ganglion is still enlarged.

Fig. 422.
7 8

Thirty-six hours.

Twenty-four hours.

At twenty-four hours (Jig 422, 7) the fourth
and fifth ganglia are completely united, the
fifth being larger than the fourth. The cords
before the sixth are enlarged, as also are the
transverse nerves of the thorax, which seem to
keep pace with or rather to precede the deve-
lopment of the respiratory organs.

At thirty-six hours (8) the optic nerves have
attained a size almost equal to that of the
cerebral ganglia, and after this period become
very little larger. During the preceding stages
of the transformation .the minute black patch
observed at their base has been gradually more
and more expanded, and carried forwards from
the posterior superior part of each lobe to its
lateral part, which at this period it is begin-
ning to cover, while the optic nerves appear as
if developing from within outwards, and have
a somewhat pear-shaped form. The first sub-
cesophageal ganglion, or medulla,now forms with
the cerebral ones a complete ring around the
oesophagus, the crura having almost disap-
peared. The fifth ganglion has decreased in
size and is now smaller than the fourth, while,
in some specimens, the nerves that arise now
come from the cords immediately behind it,
thus giving a further proof that the nervous
substance of the ganglion has been transmitted
forwards. The sixth ganglion, which at
twenty-four hours was much reduced in size,
has entirely disappeared, but the nerves that
belonged to it remain and are now derived
from the cord, very near to those which be-
longed to the fifth ganglion, thus further
proving, as formerly remarked by us,* that the
nervous substance has been transmitted for-
wards along the cord. This view of the
manner in which these changes in the form and

* Phil. Trans. 1834.

INSECTA.

965

size of different parts of the nervous system is
effected is in full accordance with the recently
developed facts of Ehrenberg and others re-
specting the tubular nature of the primary
nervous fibres.

At forty-eight hours, (fig. 423, 9) the whole of
the cords have regained the longitudinal direc-
tion, and the seventh ganglion, which had begun
to be decreased in size at the last period, has
now also entirely disappeared, and its nerves,
like those of the fifth and sixth, come from the
cord, while the ganglia of the thorax are ac-
quiring a great size.

Fig. 423.

9 10

Fo-rty-eiyht hours. Fifty-eight hours.

At fifty-eight hours (10) a further change
has been effected. The second and third tho-
racic ganglia have united, and the double gan-
glion thus formed is only separated from the
larger thoracic mass composed of the fourth,
fifth, and part of the sixth ganglia, by the short
but greatly enlarged cords which pass, as before
noticed, on each side of the central attachment
of the muscles. The transverse plexus are
united with the nerves to the wings, and the
whole of these gangliated portions of cord have
been carried forwards, and now occupy the
middle portion of the immensely enlarged
meso-thorax. The optic and antennal nerves
have nearly attained their full development,
and those numerous and most intricate plexus
of nerves in the three thoracic segments of
the larva form only a few trunks, which can
hardly be recognized as the same structures.
The arrangement of the whole nervous system
is now nearly as it exists in the perfect insect.
The whole of these important changes are thus
seen to take place within the first three days
after the insect has undergone its metamor-
phosis; and they precede those of the alimentary
canal, generative system, and other organs,
which are still very far from being completed,
and indeed, as compared with the nervous sys-
tem, have made but little progress.

Such is the rapidity of these changes, as ob-
served by us in June, 1832, in a species that
usually undergoes its metamorphosis from the
larva to the perfect state in about fourteen days.
On repeating our observation on the same insect
in the following August, when, from the in-
creased temperature of the season, the whole of

the changes in the, body were completed in
about eight days, we did not observe that these
had become much accelerated, although the
changes in the other structures were hastened.
The whole of these phenomena are induced by
an alteration which takes place in the external
tegument, and the permanent contraction of
the longitudinal and diagonal muscles of the
body, by means of which the anterior margin
of one segment is drawn beneath the posterior
of that which immediately precedes it. This
is carried to a greater or less extent in the diffe-
rent segments, and the nervous cord being in
consequence rendered too long to lie in a direct
line, a disposition is thus induced in its va-
rious parts to coalesce.

Organs of Nutrition. — The chief organs of
nutrition in insects, the alimentary canal and
its appendages, assume a variety of forms in
the different classes, and undergo changes al-
most as remarkable as those of the nervous
system. From being scarcely more than a
simple elongated tube, with a few slight en-
largements in its course, as in some of the
apodal Hymenoptera, the alimentary canal be-
comes in the perfect individual a long convo-
luted organ, thick, muscular, and divided into
several compartments, each of which is adapted
to a peculiar function, but subservient to the
more general one of assimilating the food re-
ceived, into one homogeneous material, fitted
for the nourishment of the whole body. But
whatever be its particular form, the alimentary
canal may be regarded as composed of three
distinct coats or tissues, which we shall dis-
tinguish as the external or peritoneal, the middle
or muscular, and the internal or mucous.

The pe.ritonaal coat, or layer, is an exceed-
ingly transparent, white, shining, and delicate
membrane, and is observed only with great
difficulty. It covers the outer surface of the
muscular coat throughout the whole course of
the canal, and, as we are strongly induced to
believe, although we have not positively ascer-
tained it, is continuous with and reflected
along the tracheal vessels that ramify on the
stomach, -and forms their external covering.
\Ve have never been able to detach it from the
muscular coat, which it completely invests,
and to which it closely adheres, but we have
seen it most distinctly in recently killed insects
more particularly in the Apidte, as in Antho-
phora retusa, when the canal has been removed
from the body and viewed by transmitted light.
It is then seen most distinctly extending along
the sides of the canal, directly across the
angles formed by the contraction of some part
of the muscular coat, where this is thrown into
folds or depressions.

The muscular, or middle coat, is very strongly
marked. It is composed of transverse and longi-
tudinal fibres, interlaced with each other, and also
of a series of oblique fibres, which, as shewn by
Lyonet in the Cossus, sometimes in part form the
retractoresventriculi muscles, that assist to retain
the canal in its proper position in the body, and
connect it with the whole muscular system.
Burmeister states,* that distinct transverse and

* Op. cit. (trans,) p. 121.

966

INSECTA.

longitudinal vcsxek can be discovered in the
muscular coat, but we bave never been able to
observe them. The muscular coat is most
distinct in the proventriculus or gizzard, the
ventriculus or digestive stomach, and the colon,
but may be traced throughout the whole of the
canal. The longitudinal and transverse fibres
are each developed to a greater or less extent in
different insects ; in some, more especially in
the larva state, as in the Lepidoptera, the longi-
tudinal fibres form six strong bands, arranged
at equal distances around the canal, and ex-
tended from one extremity of it to the other,
more or less developed in different parts of
their course; while in other instances, more
particularly in the perfect state, the circular
fibres are most developed, as in the Hymenop-
tera, in which the longitudinal fibres on the
stomach are scarcely observable.

The Ttnieous, or internal coat, analogous to the
mucous coat in the higher animals, is divided
into two layers, each of which has been consi-
dered as a distinct structure by different anato-
mists. The most internal of these layers forms
the proper lining of the alimentary canal, and
is a smooth soft membrane, particularly distinct
in the upper part of the canal, but less so in
the lower. It is continuous with the lining of
the mouth and pharynx, and is often plaited
or folded longitudinally, but seldom trans-
versely, excepting where it covers a fold of the
other structures to form a valve at any part of
the canal. It is this membrane which is often
solidified at the upper part of the canal, and
developed into rows of strong horny teeth, as
in the Orthoptera and some carnivorous Co-
leoptera, or is covered entirely with exceedingly
minute ones over its whole surface, as is parti-
cularly the ease in Gryllus migrator ius. In
some instances it )s very loosely attached, and
forms, as it were, a soft and easily separated
lining to the canal, more particularly in the
Tentriculus, as in the Metue and some other
genera. The other layer of this coat, which has
been regarded as a distinct structure, is situ-
ated between the proper mucous or lining
membrane and the muscular coat. It is this
layer which is considered by Straus as the pro-
per skin or lining. It is usually thin, floccu-
lent, and frequently without indications of dis-
tinct texture, although it is occasionally found
to possess it, as shewn by Burmeister in Hydro-
philus. Straus has sometimes observed horny
prominences in it, which he considers of a
glandular nature. The markings in Hydrophi-
lus appear to be of the same description. Ram-
dohr mistook this layer for a layer of transuded
chyle ; Straus and Burmeister regard it as per-
fectly distinct from the mucous coat, and Pro-
fessor Grant in alluding to it seems to regard it
as a loose intermediate cellular tissue.* This
is our own opinion also of its nature, because
we have been unable to trace it as a distinct
layer throughout the whole of the canal. It
exists most distinct in the ventriculus, but we
have not been able to trace it in the colon, ex-
cepting, perhaps, in the Lepidoptera, in which
it appears to be what we have regarded as an

adipose coat. The inner or true mucous layer
is very distinct, and in gome, as in Cerura vi-
nula, is covered with minute rounded glands.

The alimentary canal is retained in its
position in the body partly by means of the re-
tractores ventriculi, which we have observed
most distinctly in the larvae of Diptera, as in
Eri&tatis tenax, as well as in Lepidoptera and
others ; but more especially by means of rami-
fications of the trachea! vessels, which pass
from the great longitudinal tracheae, near the
spiracles, and are distributed in profusion over
the alimentary canal throughout its whole
course. Burmeister says that a peritonceum,
such as retains the intestines in their place in
the higher animals, does not exist in insects.
This, however, as we have above shewn, is not
strictly the case, since a peritonceum certainly
exists as a coat of the alimentary canal, al-
though we have never been able to observe it
forming, as stated by Professor Grant,* "a
distinct thin mesentery," connecting the con-
volutions of the intestines with the interior of
the abdominal segments.

The parts of the alimentary canal are the
mouth andpkarynx, the oesophagus, (Jig. 424,//,)
and, in the Lepidoptera, (Jig. 430, £,) Hymen-
optera, and Diptera, the crop, which is a dila-
tation of the oesophagus carried to so great an
extent as to form adistinct appendicular cavity ;
the proventriculus or gizzard (i), the ventri-
culus or proper digestive stomach (/f), the
ilium or short intestine (/), and the colon
(ro, n) and rectum (o). These exist in the
most developed form of the canal, but not in-
variably or to the same extent in every insect.
The crop is frequently absent, as are also the
proventriculus and the rectum, but the remain-
ing parts are almost constantly present. Be-
sides these as forming parts of the digestive
apparatus, there are the appendicular struc-
tures, consisting of the salivary glands (a), the
gastric («, 6, c), and the so-called biliary (p)
and the anal vessels (s). Of these the sup-
posed biliary vessels are almost constantly pre-
sent, and less frequently the salivary and gastric,
and least frequently the anal vessels, which have
not been observed in many species.

Alimentary canal of the larva. — The most
simple form of alimentary canal we have yet
met with in insects exists in apodal larvae
of parasitic Ilymenoptera, as in Ichneumon
Atroposy which undergoes all its changes
within the cavity of the abdomen, between the
alimentary canal and muscular structures of the
larva and pupa of Sphinx ligustri or Acherontia
AtropoB. It consists simply of an elongated
sac, very much dilated, and greatly resembling
a Florence flask, and occupies nearly the whole
of the interior of the body of the parasite. The
oesophagus is short and very distinct, and termi-
nates in the second segment in a well-deve-
loped valve formed by a duplicate of the mu-
cous and muscular coats. Behind this the
whole forms one dilated 'continuous cavity, ex-
tended as far as the anal segment, but com-
pletely imperforate and slightly intussuscepted
at its extremity, where, when the part is carefully

Outlines of Comparative Anatomy, p. 349.

Id. loc.ch.

1NSKCTA.

967

Fig. 424.

Alimentary canal'of Carabus mortilia.

h, oesophagus ; i, gizzard, or proventriculus ; b,
ventriculus or digestive stomach ; I, ilium ; m n,
colon, with caecal glands ; o, rectum ; p, hepatic
vessels ; q, their point of insertion •, a, anal ves-
sels ; a, b, c, a gastric vessel j a, b, a portion of the
lining of the gizzard.

examined by transmitted light, there is a slight
appearance of circular fibres. Its texture
throughout is distinctly muscular, both longitu-
dinal and transverse muscular fibres being dis-
tinctly visible in every part of it, and of nearly
uniform size. This is a remarkably low form
of development in an insect which afterwards
becomes one of the most perfectly organized of

its class. The next kwnple form of afamentary
canal occurs in the »ame order of insects, as in
the larva of the common Hornet, Vespa crabro,
in which it consists of a straight and gradually
enlarging tube, extended as far backwards as
the eleventh segment, where it becomes con-
stricted, and forms a short small intestine,
receiving at the same time the insertions of
very minute hepatic vessels, after which the
intestine becomes again slightly enlarged to
form a rudimentary colon. The next somewhat
more developed form is found in the Apnl(e, as
in Anthophoru retusa, in which the canal forms
a distinct oesophagus, which terminates in a very
slight dilatation, and then gradually enlarging,
passes onwards, as in the Hornet, until it ac-
quires its largest diameter in the eleventh seg-
ment, and becomes constricted to form the
small intestine, receiving laterally at the same
time the insertions of the hepatic vessels. The
small intestine then passes forwards, and after
making one short sigmoid turn backwards, ends
in a straight colon and anal aperture, which is
distinctly developed in this insect towards the
latter part of the larva period, at which time,
after the insect has become full grown and
ceased to feed, we have observed faeces passed
from it, but we have reason to believe that the
anal aperture is not developed until that period,
since no faeces are found in the cell in which
the larva is inclosed until after the larva is full-
grown, and has eaten the whole of the food that
was stored up with it when the cell was closed
by the parent. In the larva of some Coleop-
tera, as in the Lamellicorne*, there is almost as
simple a form of the alimentary canal as in the
Apidtf. In these, as in Melolontha vulgaris,
(jig. 425,) it commences in a short and narrow
oesophagus, which opens by a valve into a very
capacious stomach that extends backwards to
the twelfth segment of the body, where it is
gradually decreased in size, and ends in a nar-
rowed pylorus, which is divided internally by
a valve from a short and narrow intestine,
that passes forwards beneath the stomach,
and ends in a very large colon, which at its
commencement is dilated into an immense
ccecum, and is in general distended with faeces.
It terminates beneath the middle of the
posterior half of the stomach in a rectum,
which passes directly to an anal aperture.
In our dissection of this larva we did not observe
the exact point at which the biliary vessels enter,
but nevertheless they exist, although less distinct
than in the perfect insect. They were observed
by Swammerdam in the larva of Oryctes nasi-
cornis* entering, four in number, at the pylo-
rus. In this and other lamellicorn larvae the
surface of the digestive cavity is increased by
the addition of three series of ccecal appen-
dages. The first surround the cardiac extre-
mity, and consist of twelve ccecal tubes, with
their apices directed forwards, and dilated on
each side into four smaller creca, so that each
one has somewhat the appearance of a fern-
leaf. From the situation which they occupy,
these may perhaps be regarded as salivary
organs. A little beyond the insertion of these

* Biblia Nat. tab.xxvii. fig. V. c.

9C8

INSECTA.

Lateral view of the alimentary canal of the larva of
Melolontha vulyaTis, with the three series of gastric
vessels.

vessels the stomach is slightly constricted, and
receives the insertions of another set of coeca,
which differ from the last in being single, co-
nical, and directed backwards. At some dis-
tance beyond these, the stomach is encircled
by a third set of coeca, which differ from both
the preceding in being united in pairs at their
base, and inserted, with their apices directed
forwards, near the posterior part of the stomach.
Those cceca, both of the second and third
series, which are nearest to the upper part
of the stomach, are the shortest. These cceca
are not analogous to the hepatic vessels, or ra-
ther those usually so designated, but to the
gastric glands which cover the stomach in the
Carabida (Jig. 424) and Lucanida (Jig. 428),
and appear in this voracious larva designed to
secrete a fluid that may be necessary to enable
the stomach to digest the immense quantity of
vegetable matter taken into it. In the Lepi-
dopterous larvae the canal is scarcely more
developed than in the Coleopterous, since,
although the oesophagus is elongated, and
the larger intestines are somewhat more
complicated, no series of gastric glands are de-
veloped. We believe we have seen those which
surround the cardiac extremity in some ~Romby-
cld&j as in Odonestis potatoria, immediately
after the insect was killed, but merely as little
rounded protuberances, the character of which
was completely lost after the insect had been
preserved for a short time in spirits of wine.
They exist also very distinctly in the Sphinx.
In this order it commences by a distinct eso-
phagus (Jig. 364, c), which terminates by a val-
vular orifice in the third segment in a long and
very muscular stomach (C), around which the
six longitudinal bands are very distinct, as also
are the transverse muscular ones. At the com-
mencement of the eleventh segment it becomes
constricted, and terminates in a distinct pylo*
rus, which ends in a short ilium (e), into the
middle of which, on each side, are received the

united termination of the hepatic vessels (f )f
which, having extended along the sides of the
stomach as far forwards as the seventh segment,
are convoluted around this and the remaining
portion of the canal. Immediately behind the
ilium the canal is developed in a six double-
lobed ccecum (g), and immediately afterwards
into an immense sacculated colon (/*), termi-
nated by a very short rectum. The longitu-
dinal bands are particularly distinct on the
colon, and extend from its posterior part to the
external muscular tegument forming the retrac-
tors of the colon and rectum. In the active
larva of Coleoptera the alimentary canal be-
comes still more developed. It commences in
the larvae of the Carabid<e9 Culosotna syco-
phanta (Jig. 426), according to Burmeister,* in
a very short oesophagus (II),
Fig. 426. that opens at the posterior
part of the pro-thoracic seg-
ment into a large cylindrical
stomach (K), which is ex-
r"lf fllfiff*^ tended throughout the great-
•m<ljL er part of the body, very si-
milar in appearance to that
of the Lepidoptera. This
is called by Burmeister the
craw. It opens directly
into another cylindrical sto-
mach, much narrower and
nearly of the same length,
but more muscular than the
preceding, and receiving
its posterior extremity (Q),,
where it forms internally a
distinct pyloric valve, the
hepatic vessels. Burmeister
| A remarks that there is no
*vi valve of separation between
the first and second of these
stomachs, nor any rudiment
of the gizzard, which exists
in the perfect insects of this-
order (fig. 424, i). These
are succeeded by a small
intestine or ilium (L),
which is of some length,
and together with the se-
cond stomach forms several
convolutions in the body
between the first stomach,
or craw, and the great in-
testine or colon (M), which
follows it, and terminates
the canal in a protruded
Alimentary canal of anal aperture (O). The
colon, as in most larvae, is
very muscular and folded
transversely, and altogether
the canal is more developed than in the pre-
ceding instances, as also are its appendages
the hepatic vessels, which are exceedingly
long, although no cceca are developed upon
them. In the lihinchophora and Longicornes
there is a still higher form of alimentary canal,
as observed by Burmeisterf in Calandra

* Transactions of Entomol. Society of London.
Vol. i. part 3.

t Zur Naturgeschichte der Gattung Calandra.
Berlin, 1837.

soma sycopJianta.
(Burmeister.)

INSECTA.

969

Sommert, and as seen by ourselves in Cullidium
luridum. In Calandru, which in external ap-
pearance is scarcely more perfect than the
apodal larva of Ilymenoptera, the alimentary
canal (fig. 427) approaches much in form,

Fig. 427.

A limentary canal of the
larva of Calandra Som-
tneri. ( Burmeister. )

size, and complication of its parts to that of
the perfect insect. It commences behind the
pharynx in a very short pear-shaped oesopha-
gus (II), which opens by a valve into a dilated
bag-shaped crop (I), analogous probably to
the first stomach of the larva of Calosoma. This
is continuous by a narrowed passage with the
proper digestive cavity, around the middle part
of which (K) are developed many conical glan-
dular papillae or gastric vessels, that do not
appear to have been noticed in the larva of
Calosoma, which instead of subsisting upon
hard vegetable substances like these Curculio-
nidtf, preys upon the soft bodies of living cater-
pillars, and consequently does not require for
the digestion of its soft animal food and juices
so complicated a structure as those which de-
vour large quantities of crude vegetable matter,
as is the habit of the Lamellicornes, or the hard
and less easily solvent woody fibre or coverings
of insects devoured by the Calandra or the
perfect Carabida. At the posterior extremity
of the digestive stomach in this larva are in-
serted, as before seen, the biliary vessels, not
singly around the sides of the canal, but by

the union of four of these tubes in a common
duct. This peculiarity is remarkable, as it
occurs in some species in the perfect in-
sect. Besides these vessels there are two
others somewhat smaller, which are inserted
separately, a little anterior to the common duct.
These have been supposed to be analogous
to pancreatic vessels, but they are similar
in almost every respect to those which are
inserted by a common duct, and hence may
be supposed to have nearly the same functions.
We have noticed similar vessels inserted sepa-
rately from the supposed hepatic vessels in the
Dyticida and in Timarcha, which certainly
leads to the conclusion that they have some
difference of function. The ilium (L) is of
great length, and more convoluted than we
have yet seen it in any larva, and ends in a very
muscular cylindrical colon (M N), terminated
by a short rectum. A similar and perhaps
even more highly developed form of alimentary
canal exists in Callidum luridum, in which the
anterior portion of the oesophagus commences
with a small neck, and is then enormously di-
lated, after which it becomes gradually narrowed
and constricted, and is joined to a second sto-
mach, which in like manner is also dilated at
its anterior extremity. In the middle part of
its course it is twice folded, and is covered with
minute cceca, as in Calandra, like which it ter-
minates in a valvular pylorus, and receives at
the same time the insertions of the hepatic ves-
sels. The ilium is also of considerable length,
is exceedingly muscular, and is dilated in two
parts of its course before it terminates in a
straight and very muscular colon and short
rectum, as in Calandra. The length and com-
plication of the intestines, therefore, appear to
have some reference to the quality of the food
to be digested, since it is well known that the
food of these latter insects is of difficult assi-
milation, being as it is chiefly the hard ligneous
fibres of vegetable matter ; but they cannot be
received as always indicatory of a carnivorous
vegetable feeder, since, as above remarked, the
length of the canal is considerable in one en-
tirely carnivorous larva, while it is much shorter
in some herbivorous, and particularly in polleni-
vorous larvae, as in the Alelolontha and the
apodal Hymenoptera.

In the perfect insect, the length of the ali-
mentary canal is not more indicatory of the ha-
bits of the species than in the larva. It is
nearly as long, and is more complicated, in the
rapacious Carabida (Jig. 423) than in the
honey-sipping Lepidoptera, whose food is en-
tirely liquid, while, as we have seen, it is only
a very short tube in the pollenivorous larva,
which subsists upon a mixture of pollen and
honey ; but in the perfect insect, which subsists
upon honey alone, and which it might be sup-
posed requires little power of digestion, the
canal is long and tortuous. In the rapacious
Carabida, it is from two to three times the
length of the whole body. At its commence-
ment at the pharynx it is funnel-shaped, and
opens directly into the oesophagus (Jig. 424, A),
which is gradually enlarged as it passes through
the thorax, until it arrives at the meta-thoracic
segment, where it becomes greatly dilated, and

970

INSECTA.

forms a large bag or crop, which we shall pre-
sently see more perfectly developed in the
Haustellata. While passing into the abdomen,
this part becomes suddenly constricted, and
terminates in a short neck, immediately behind
which is an oval and very muscular gizzard (i),
which is developed internally into four broad
longitudinal horny ridges (a, b), armed with
strong sharp bristles, as formerly shewn by
Leon Dufour* in insects of this family. Be-
tween these ridges are two channels armed in
like manner with a double row of minute
hairs, which assist in more minutely comminu-
ting the hard parts that are passed into the
gizzard and escape trituration by the ridges.
The substance of the gizzard is particularly
muscular, and resembles in colour the gizzard of
a bird. On its external surface the thin shining
peritonceal coat is very distinctly seen. At its
base the gizzard is much constricted, and the
ridges within it meet together so as to form a
distinct valve, by which this is divided from the
next portion of the alimentary canal, the chylific
venthcule (A;). This part is capacious and
muscular, and the double mucous lining within
it is very distinct. It is of considerable length,
and is gradually decreased in size from its com-
mencement to its termination at the pyloric
valve, where, as in the larva, it receives the he-
patic vessels. It is v covered throughout its
whole course by an immense number of appa-
rently ccecal vessels (a, 6, c), which in the upper
half of its course are of considerable length,
but in the lower become gradually more and
more shortened. Burmeisterf thinks these
coecal vessels are derived entirely from the inner
or mucous coat of the ventricule by intussus-
cepted portions, which pass through the mus-
cular coat between the fibres which are pushed
aside by them, and consequently that they do
not derive any covering from the muscular coat,
but of this we have considerable doubt. In-
ternally they certainly open each by a distinct
valvular orifice, derived from the mucous lining,
as we have seen in Carabus monilis (6), and
externally are covered by the peritonceal coat,
and on each side are furnished with a minute
ramifying tracheal vessel, derived from the tra-
cheae which are distributed over the alimentary
canal, as shewn by Dufour. We cannot, how-
ever, imagine that they derive no covering from
the muscular coat of the ventricule, more espe-
cially while it is admitted that the coecal appen-
dages attached to the anterior and posterior por-
tion of the ventricule in the GryllidcE derive a
portion of their structure from the muscular
coat as well as the mucous. These are most
decidedly secretory organs, and elaborate a
fluid, probably distinct in its chemical composi-
tion from that of the biliary vessels at the
pyloric extremity of the stomach. The ilium
(/) is of considerable length. On its exterior
surface the longitudinal muscular bands are
distinctly marked. It is much longer in pro-
portion to the other parts of the intestine in the
perfect insect than in the larva. It terminates
in a very large pear-shaped colon (m, n), the

upper part of which corresponds to the coscum,
which we shall see highly developed in some
other species. It is there marked by six elon-
gated elevated glandular protuberances, situated
between the longitudinal muscular bands.
These elevations seen on the exterior of the part
correspond to others which we have found
equally strongly marked in the colon of Hy-
menoptera, and we suspect are the mucous
glands of the great intestine. The colon is
usually distended with fasces, and terminates in
a very short narrow rectum (o). At each side
of the colon are situated the anal or urinary
vessels (s), which we shall presently describe.
This may serve to illustrate the general form of
the alimentary canal in carnivorous Coleoptera.
In certain parts of its course it is, however,
more developed in other species. Thus in the
Dyticida:, we have found the oesophagus in
Hydaticus cinereus, as described by authors in
DyticttSj expanded into a large crop-shaped
bag, and the stomach shorter than that of the
Carabid&t and covered by Ions; cceca throughout
its whole extent. It receives at its base the in-
sertion of four large hepatic vessels, and also
two very much smaller ones, similar to those
just seen in thelarva oftheCalandra. The anal
vessels are also present, but their excretory
bladder is larger, and its neck much shorter
than in the Carabida. The most remarkable
structure is in the proventriculus or gizzard.
The external appearances of this part resembles
that of an acorn in its cup. It is exceedingly
muscular, and is armed internally with four re-
markable teeth arranged around its inferior por-
tion, between four horny ridges developed from
the mucous lining of the part, and covered with
very strong stiff hairs, as in the Carabida. Each
of these teeth is broad and somewhat oval at its
base, and in shape resembles a helmet, the crest
of which is acute, and armed with two sharp-
pointed prominences adapted for cutting the
food, which it is known is swallowed more rapa-
ciously and less comminuted by these insects
than by Carabida. This form of alimentary
canal with a gizzard and gastric cceca exists in
the Silphida* and most of the carnivorous
feeders. Thus it exists also in Staphylinidefi
in which we have found the gizzard in Creoplii-
lus maxillosus armed with double longitudinal
horny ridges, covered with stiff hairs as in Ca-
rabus, like which also the stomach is covered
with gastric co3ca, which are larger at the an-
terior than at the posterior part of the organ.
The anal vessels are also largely developed.
Dufour has observed the same in Staphyli-
nus erythropterus. The gizzard is also found
in some of the Neuroptera. It is very largely
developed in the carnivorous Panorpa corn-
munis, in which, however, we have not found it
thrown into regular longitudinal folds, but into
transverse and oblique rugae covered with stiff
hairs. The alimentary canal in this species is of
considerable length, perhaps nearly three times
that of the body. The oesophagus is short,
but is developed at its under "surface into
a minute oval crop, perfectly distinct from

* Annales des Sciences Naturelles, torn. ii. pi. 20.
t Op. cit. p. 132.

* Dufour, op. cit. torn. iii. pi. 13, fig. 5.
t Id.

INSECTA.

971

the common cavity of the oesophagus, although
not separated from it by a valve, neither is the
oesophagus separated by a valvular structure
from the gizzard. The chylific stomach is ex-
ceedingly long and cylindrical, but is without
gastric coeca, like the larva of Carabidte, since
like that, the Panorpa appears to subsist rather
by sucking the juices than by swallowing the
hard parts of the body of its victims. Thus,
then, although in the Cicindelidie (Jig. 37, vol. 1),
the canal is scarcely longer than the body, as
formerly shewn by Dufour, and since fre-
quently instanced as proving that the length or
shortness of the canal is characteristic of a car-
nivorous or phytophagous feeder, we cannot
admit that the length of the digestive organs,
and the existence of a gizzard and gastric ves-
sels, are indicatory of predacity of habits in the
insect, because a similar conformation of parts
exists often in strictly vegetable feeders. The
existence and length of these parts seem rather
to refer to the comparative digestibility of the
food than to its animal or vegetable nature.

Among the more omnivorous feeders, as in
the Forficulida, the gizzard is still present.
In Forjicula auricularia the oesophagus is
long and dilated, and a short, broad, and very
muscular gizzard is present. Internally it is
thrown into six longitudinal folds, which pro-
ject for some distance at their extremity into
the cavity of the digestive stomach, to the en-
trance of which, when closed, they serve as a
valve. The canal of this insect, which, although
in part carnivorous in its habits, certainly is
not of the most rapacious nature, but lives
equally upon the juices of fruits and flowers, is
scarcely longer than that of the most predaceous
Cicindela or Dyticus, since it passes almost in
a direct line through the body, making but one
slight convolution, a further proof that the
length of the canal must not be taken as a cri-
terion whereby to judge of the habits of a
species. This will apply equally to the om-
nivorous Gryllidte, in which there exists a short
alimentary canal, but a gizzard of more com-
plicated structure than that of Dyticida. In
these insects the two layers of the mucous
coat are visible even in the oesophagus. The
second layer is distinctly glandular and secre-
tory, and in it there are many thousands of
very minute granulary glandular bodies, which
probably secrete the fluid that is often ejected
from the mouth of the insect when captured.
The inner layer, or proper mucous lining, is
often folded longitudinally, and in Acrida
viridissima these folds, which are six in number,
assist to form a valve between the oesophagus
and gizzard. They are each armed with five
very minute hooked teeth, and continued into
the gizzard develope many more in their course
through that organ. These first teeth are ar-
ranged around the entrance to the gizzard, and
seem designed to retain the insufficiently com-
minuted food and pass it on to that organ.
Next to these in succession on each of the lon-
gitudinal ridges are four flat, broad, and some-
what quadrate teeth, each of which is very
finely denticulated along its free margin. These
extend about half-way through the gizzard.
They appear to be alternately elevated and de-

pressed during the action of the gizzard, and to
serve to carry on the food to the twelve cutting
teeth with which each ridge is also armed, and
which occupy the posterior part of the organ.
These teeth are triangular, sharp-pointed, and
directed posteriorly, and gradually decrease in
size in succession from before backwards. Each
tooth is very strong, sharp-pointed, and of the
colour and consistence of tortoise-shell, and is
armed on each side by a smaller pointed tooth.
These form the six longitudinal ridges of the
gizzard, between each two of which there are
two other rows of very minute teeth of a tri-
angular form, somewhat resembling the larger
ones in structure occupying the channels be-
tween the ridges. The muscular portion of the
gizzard is equally interesting. It is not merely
formed of transverse and longitudinal fibres,
but sends from its inner surface into the cavity
of each of the large teeth other minute but
powerful muscles, a pair of which are inserted
into each tooth. The number of teeth in the
gizzard amounts to two hundred and seventy,
which is the same number in these Grylfaue
as found formerly by Dr. Kidd* in the mole-
cricket. Of the different kinds of teeth there
are as follows : seventy-two large treble teeth,
twenty-four flat quadrate teeth; thirty small
single-hooked teeth, and twelve rows of small
triangular teeth, each row being formed of
twelve teeth. This is the complicated gizzard
of the higher Orthoptera. In the same insect
immediately posterior to the gizzard the chylific
stomach is expanded on each side into two
large rounded cceca, into the upper part of which
some minute vessels are traced which in appear-
ance resemble the hepatic vessels. Posteriorly
to these coeca the stomach becomes narrowed
and makes one convolution, and receives around
its termination the hepatic vessels, which are
small but very numerous. It then is continued
backwards as a long ilium, and terminates in a
muscular banded colon without a distinct
rectum. The whole length of this alimentary
canal does not exceed more than about one
length and a half of that of the body. A simi-
lar structure exists in the Blattida. In these
insects eight large vessels are inserted around
the commencement of the stomach behind the
gizzard. Four of these are long and four short,
and as observed by Burmeister, these have been
thought to be analogous to pancreatic or
gastral salivary organs. In the proper Locust ida
there is only a rudimentary gizzard, as Bur-
meister has shown in Locusta migratoria, in
which the interior lining of the whole oeso-
phagus and crop is covered by an immense
number of very minute horny teeth, for the
purpose of comminuting the hard ligneous
matter which we have sometimes found in
foreign specimens. The rudiments of the
gizzard exist in six flat pieces, studded with
minute teeth like the lining of the oesophagus.
The commencement of the stomach is sur-
rounded by two sets of coecal appendages, six
in each set, and similar in form to those of the
second set in the larva of Melolontha, like
which those on the under surface are the

* Phik Trans. 1826.

972

INSECTA.

Fig. 428

Alimentary canal of Lucamis cervus. .

G, anterior muscles of the pharynx; H, oeso-
phagus ; I, gizzard ; K, chylific stomach ; L, ilium ;
M, colon (coecal portion of) ; N, colon ; O, rectum j
«, frontal ganglion on the vagus ; b, vagus ; e, an-
terior lateral ganglion connected to the vagus.

longest. These are evidently analogous to the
vessels in Elatta.

But one of the most remarkable forms of
alimentary canal with reference to the habits of
the insect exists in the male Lucanus cervus
(Jig- 428), which subsists entirely upon fluid
aliment, as proved by the observations of natu-
ralists, and confirmed by the fact that its mouth
is unfitted for mastication. In this insect the
oesophagus (H) is usually long and narrow, and
terminates in the meso-thorax in a well deve-
loped gizzard (I), as in the Carabus, and this
is succeeded by a long chylific stomach (K),
covered throughout its whole extent by very
minute rudimentary coeca, as first noticed by
Dufour. It makes three distinct convolutions,
and is then divided by a pylorus, which re-
ceives four hepatic vessels (P) from an ex-

ceedingly short ilium (L), which passes directly
in an enormous colon. The upper portion of
this (M) is divided from the lower (N), which
is thus divided into colon and ccecum. It ter-
minates in a long folded rectum (N, O), and
the whole are usually filled with faeces. Now
this insect, in which both gizzard and gastric
vessels are present, can scarcely require these
parts for the purpose of triturating its food,
which is entirely fluid, besides which, being
one of those species that undergo a complete
metamorphosis, it can scarcely be supposed to
be simply a remains of what existed in the
larva state. The presence of the gizzard may
be looked upon as somewhat anomalous.
Again it may be remarked, that in Hymenoptera
the stomach, which in many species digests
only liquid concentrated food in the form of
honey, is much longer than in those instances,
as in Orthoptera, in which the food is less
easily digestible. In the Apida there is a large
alimentary canal with an immense number of
biliary vessels attached to it, while in the
Tenthredinida, which, besides honey, subsist
partly upon the pollen of flowers, as we have
observed in Athulia centifolta, there is a very
short alimentary canal and even a distinct
gizzard (Jig. 429, I), situated between the

Fig. 429.

Section of the crop (H), gizzard (I),
(K) of Athalia centifolice. (Newport, 1

and stomach
Prize Essay).

stomach (K) and the dilated oesophagus (H)
or crop of this order. We have detected pollen
in the proventriculus of this insect, so that in
these we have still further proof that the length
of the canal is not always indicatory of the
habits of the species.

In the Lepidoptera, which, we have seen, in
the larva state have a short intestine, have a com-
paratively long one in the perfect. In the
Sphinx ligustri (fig. 430), the oesophagus (h) is
long and narrowj and in the metathoracic seg-
ment is dilated into a large crop (£) connected
by a distinct neck, but not divided from it by a
valve. This is usually filled with air, and has
thence been called the sucking stomach, but in
the Diptera, in which it also exists, and com-
mencing much nearer the pharynx is extended
backwards as a long and gradually enlarging
tube until it reaches the anterior part of the
abdomen, where it is expanded transversely
into a large bag, we have certainly found it
partially filled with food. This has often been
found to be the case in the common flesh-fly.
In EristalisjloreusC1.) we have found it partially
filled with yellow pollen from the flowers of
the ragwort, upon which the insect was cap-
tured. We have at the same time observed

INSECTA.

973

Fig. 430.

Fig. 431,

Alimentary canal of Sphinx Kgtutri.

the pollen in the canal leading to the bag, in
the oesophagus, and in the stomach itself. A
gizzard does not exist either in the Diptera or
Lepidoptera, but there is a slight rudiment of
it in the Sphinx (i). The stomach of Lepidop-
tera is in general short, oval, or a little elon-
gated (/c), and always very muscular, and as
in other insects, the hepatic vessels (/>) enter
.at its pyloric extremity (</). The ilium (/) is of
considerable length. In the Sphinx it makes
seven folds, and then passes straight to the

• Alimentary canal of Pontia brassicce.

colon, which is developed anteriorly into a very
large ccecum (;/z), and terminates in a narrow
short rectum (n). Throughout its whole course
it is covered by the hepatic vessels. In the
Pontia brassier (jig. 431), the digestive sto-
mach is preceded by a very muscular and
transversely banded portion of canal resembling
the stomach of Hymenoptera. It is in the pre-
cise situation of the gizzard in other orders, and
appears to be the representative of that part in
this insect. The true stomach is long and oval,
and the ilium is longer than in the Sphinx, and
the ccecum, colon, and rectum are all distinct.
In the Diptera the alimentary canal is usually
very long, and is scarcely at all shorter in the
carnivorous than in the omnivorous feeders.

Appendages of the canal. — The first of these,
the salivary glands, are very frequent in most
of the orders, but vary greatly in form and
number. In Lepidoptera they are simple
elongated tubes (h\ which extend into the
thorax and are convoluted beneath the oeso-
phagus and anterior portion of the alimentary
canal. In the larva they constitute the silk
vessels, and empty themselves by a single duct
through the spinneret on the floor of the
mouth. They are formed of three por-
tions; first, the excretory, which is thin and
transparent, and is gradually enlarged as it
passes backwards along the body; second, the
apparently secretory portion of the organ, which
is of an elongated cylindrical form, externally
transversely marked as if formed of muscular
fibres, and internally covered with a vast
number of rounded glandular bodies, as we

974

INSECTA.

have seen in the recently detached vessel of
Vanessa urtictz ; and lastly of a third portion,
which consists of a minute vessel, extended
from the apparently ccecal extremity of the
middle portion of the organ, as formerly shewn
also by Lyonet in the Cossus. In the perfect
insect these parts still exist, but very much
reduced in size. In the Cossus Lyonet has
shewn four of these vessels, two of which, the
proper silk vessels, open by a single excretory
duct, and the others separately into the cavity
of the mouth. In some Coleoptera, as in the
Blapsida, these organs are formed of many
ramifying tubes united on each side of the
oesophagus into a single duct. In others, as in
the Orthoptera and Hymenoptera, they con-
sist of an immense number of rounded, opaque,
glandular bodies, aggregated together in small
clusters, which communicate by many small
ducts, inserted at irregular distances, with a
large and partially convoluted common or ex-
cretory duct, that opens on each side of the
mouth, so that each of these collections of
glands resembles a bunch of grapes or currants.
Each of these rounded granules, or acini if we
may so call them, receive a minute vessel,
but whether this is distributed over its surface
or is received directly into its substance we
.have been unable to ascertain. These aggre-
gations of salivary glands are usually situated
on each side beneath the oesophagus in the pro-
thorax, and are very distinct in the Orthoptera
and Hymenoptera, in which they have been
often noticed. Miiller has seen them in
Phasma, Treviranus in Apis, Burmeister in
Locust ida, Gryllida, and Termes, and we have
also seen them in Locust idte and GryllicUs among
the Orthoptera, and in Bombus, Apis, Antho-
plwra, and Athalia among the Hymenoptera.
Their existence in the latter genus is somewhat
interesting from the circumstance that the large
quantity of salivary fluid which these organs
seem calculated to produce appears to be
entirely employed in moistening the dry pollen
of flowers upon which the perfect insect chiefly
subsists, before it is passed into the oesophagus,
and not in the habits or in constructing of a
nest, as is the case with the bee, which always
employs it as a solvent for the wax in the con-
struction of its combs. In the latter insect,
according to Burmeister, the evacuating duct
of these organs is a minute spiral vessel re-
sembling a trachea, and empties itself into the
tube of the proboscis or ligula. The form and
number of these salivary organs varies in the
different classes; the usual number is two,
but in Apis Cimex and Pulex there are four,
each pair of which unite into one duct, while
in Nepa there are as many as six.* In the
Tabanidtf there are only two short ccecal tubes,
into which many minute vessels empty them-
selves .f Those gastric vessels, which are in-
serted at the commencement of the digestive
stomach we have above stated have been re-
garded as salivary organs, but there is consi-
derable doubt respecting their real function.
Burmeister considers them to be analogous to
the pancreas, but if this be admitted to be the

case in the Orthoptera, those vessels also which
cover the exterior of the digestive stomach in
the carnivorous Coleoptera must be of the
same description, since both empty themselves
into the digestive stomach. But we cannot
coincide with him in this opinion, since frojn
an experiment which we shall presently notice
there is reason to believe that the fluid poured
into that cavity during digestion is of an acid
nature, analogous to that which is found under
similar circumstances in the stomach of ver-
tebrata; while that of the proper salivary
organs is believed to be alkaline, as was for-
merly supposed by llengger. Treviranus also
believed the same of the saliva of the honey-
bee, having witnessed its employment by this
insect in the formation of its combs. We have
also seen this insect reduce the perfectly trans-
parent thin white scale of newly secreted wax
to a pasty or soapy consistence, by kneading it
between its mandibles, and mixing it with a
fluid from its mouth, before applying it to
assist in the formation of part of a new cell,
so that we have good reason to believe that the
salivary fluid thus employed as a solvent for the
otherwise brittle wax is of an alkaline quality.
The Malpighian or supposed biliary vessels
(Jig- 432, p) usually enter the canal, as we
have seen, at the pylorus. They vary greatly
in number from two to twenty or even a hun-
dred, as in some of the Orthoptera and Hymen-
optera, but in all insects their function appears
to be similar. They are usually from four to
six in number, and are very long tubes that
pass from their insertion or opening into the
canal behind the pylorus directly forwards
about half way along the sides of the stomach,
and are then reflected backwards as far as the
ilium, around which and the colon they make
many convolutions, and in the Lepidoptera
terminate, or perhaps we ought rather to say
originate, each in a minute vessel, which be-
comes smaller and smaller in proportion to its
length, and in which we can perceive no dis-
position to form a ccecal termination, although
we have been unable to trace it to its origin,
which is certainly in the vicinity of the posterior
part of the colon. Of this we have satisfied
ourselves by following these vessels in the larva
of Odonestis potatoria, which the colour of
their contents, an opaque bright yellow, has
rendered practicable. We have traced them
until the yellow colour has disappeared in an
opaque white, and this has been also lost in a
perfectly transparent fluid, after which we have
been unable to follow the vessels further. In
other insects they appear to end in ccecal ex-
tremities, but we certainly could not observe
this in the larvae of Lepidoptera. It has also
been supposed by some anatomists that these
vessels form a double communication with the
alimentary canal, but this has entirely escaped
our observation. In the larva of Sphinx ligustri
and most other Lepidoptera these vessels are
covered by an immense number of minute oval
OEciform dilatations (Jig. 432, a), as is also
the case in some of the perfect Coleoptera,
Melolontha* as shown by Dufour, Straus

Burmeister, op. cit, p. 146.

t Id. 145.

See Animal Kingdom, vol. i. fig. 38, c.

INSECTA.

975

Fig. 432.

a, part of the hepatic vessel of the larva of Sphinx
ligustri when nearly full grown, showing the
coeca ; b, part of the same in the pupa, the coeca
disappearing,

Durckheim, and others. From each of these
supposed cceca in the larva of sphinx we have
traced an exceedingly minute and transparent
vessel which has appeared to be connected with
other delicate ramifications, and sometimes
with the immense quantity of adipose sacculi
with which the whole viscera are surrounded.
These Malpighian vessels undergo considerable
changes while the insect is passing from the
larva to the perfect state. The cceca begin to
disappear soon after the insect has entered the
pupa state (/>), and not a trace of them is dis-
coverable in the perfect insect, so that the
function of the organ is gradually diminished
in activity. During the larva state they exhibit
a remarkable peculiarity at their connexion -with
the alimentary canal which seerns to have some
reference to their function. It is a dilatation
at the point of union of these vessels in the
sphinx to form a single duct that opens into
the ilium, and if these be hepatic vessels may
represent a gall-bladder, as once observed to
us by Dr. Grant, but the exact function of the
vessels is very difficult to determine. The
following observation which we made in the
summer of 1832 and have since repeated seems
a little to show the nature of the contents of
these vessels, and also of other parts of the
alimentary canal. We gave sugared water,
coloured with indigo, to some specimens of
Vanessa urticte which had been confined for
several hours without food after they had left
the pupa state. On examining the insects
about two hours afterwards the stomach was
found filled with fluid containing a great quan-
tity of pink-coloured granules, which appeared
to be the vegetable indigo acted upon by the
acid contents of the stomach by which it had
become saturated, thus distinctly indicating the
presence of an acid in the stomach during
digestion. But it was remarkable that some of
the indino that had passed the pyloric extremity
of the stomach, where these supposed biliary
vessels enter, and had also passed throughout
the whole length of the ilium and even in part
into the colon, had been restored again to
its original dark blue colour, thus indicating
the presence of an alkalescent fluid secreted
either by the hepatic vessels or the ilium along
which the indigo had passed. But another
curious circumstance was that the hepatic ves-
sels also partook of the same pinkish hue as
the contents of the stomach, which seemed to
indicate that the contents of these also are acid.

The conclusions we drew from these observa-
tions, which we repeated very carefully in
1834, were, that there is an acid gastric juice
secreted in the stomach during digestion, that
the contents of the so-called hepatic vessels are
probably also acid, and that an alkaline fluid
is secreted by the ilium, otherwise the indigo
reddened in the stomach could not have been
restored to its original colour. These circum-
stances seem to lead to the conclusion that the
Malpighian vessels are rather uriniferous than
biliary, more especially as they have been
found by Chevreul* and Audouinf to contain
uric acid ; but if this be really their function,
a question then arises why they are inserted so
near to the pyloric extremity of the stomach in
almost all insects, and the excreted fluid be
thus required to traverse nearly one-half of the
whole alimentary canal before it is ejected from
the body ? This consideration still inclines us
to suspend our opinion as to their true function,
and leads us still to believe that they may be
in some way connected with the function of
digestion and assimilation.

The anal or proper uriniferoits organs. — We
agree with Burmeister that the anal are the
true urinary organs. They do not in general
evacuate their contents directly into the canal,
but on each side of the anus. They exist, as
we have seen, in the Carabidee (fig. 424, s),
and their general form, as long ago shown by
Dufour in these insects, is that of a long vessel
convoluted upon the colon and emptying itself
into an oval or kidney-shaped vesicle on each
side of the colon, and terminating in a single
duct close to the anus. Dufour found the
minute vessel on the colon connected with an
aggregation of rounded glandular bodies, each
connected with the vessels by a very minute
filament, but we have overlooked this structure
in our own examinations. Neither have we
seen it in the Dyticidte, in which each urini-
ferous organ commences in two apparently
coecal tubes, which, after being a little convo-
luted, unite into one which empties itself into
a vesicle on each side of the colon and rectum.
Similar vesicles have been shown by Dufour in
the Stapkylinida, as in Staphylinus erythropterus
and in the Silphidte, in both which we have
ourselves distinctly seen them arising by a
single vessel which empties itself into an urinary
bladder on each side of the anus. In the
Silphida this bladder opens directly into the
termination of the rectum.

The adipose tissue. — -This tissue, which it is
necessary to allude to in connexion with the
organs of nutrition, consists of an immense
number of little transparent membranous vesicles
filled with opaque adipose matter, which, in
the generality of insects, is perfectly white, but
in others, as in the butterflies, is of a bright
yellow colour. The vesicles are usually very
irregular in form, being sometimes nearly oval
and at others elongated or triangular. They
communicate freely with each other and form
a most intricate web or reticulated structure.
They cover the whole of the abdominal viscera

* Straus Durckheim,Considerat. &c. 1828, iv. 251.
t L'Institut. 133.

976

INSECTA.

like the omentum of the higher animals, and
they are extended also among the muscles,
between which they occupy the interstices, both
between the different layers and the tegumen-
tary skeleton. They do not form in the abdo-
men one continuous surface like the mesentery,
but are simply attached to each other, and to
the surrounding structures by constricted por-
tions, which allow of the freest communication.
They are most abundant in the abdomen, but
are extended into the thorax and cover more
particularly the nervous cord. There are but
very few in the region of the head or in the
extremities. We have never yet seen them
in actual communication with bloodvessels,
although we have observed them attached by
minute points along the whole course of the
dorsal vessel, in the abdomen, as if they were
in some way connected with the return of the
blood to the auricular space that appears to
surround that organ. It is amongst these
vesicles in particular that the Malpighian or
so-called biliary vessels extend around the
alimentary canal, and the tracheae ramify among
them in the greatest abundance, but we have
not observed them distributed over the sides of
individual vesicles as over some other structures.
These circumstances lead us to suspect that
the vesicular structures are in some way con-
nected with the circulatory system, although
they cannot be regarded either as arteries or
veins. May they not serve the purpose of
lymphatics, while they become at the same time
depositaries of the nutrient matter ? Oken and
Treviranus appear to have considered them as
analogous to the liver, and the latter author
has supported his opinion by the existence of a
somewhat analogous structure in the scorpion,
which is believed to be the liver of that animal.
That they are most intimately connected with
the function of nutrition is proved by the cir-
cumstance that they exist in the greatest
abundance at the period when the larva ceases
to feed, just before it enters the pupa state;
that their contents are gradually diminished
during that condition ; and that they disappear
most rapidly towards the latter end of the
pupa state, when the organs of generation are
in the most rapid progress of development.
After the insect has entered the perfect state
their contents have nearly disappeared. Added
to these circumstances we have observed that,
during the earliest periods of the larva state,
the quantity of adipose substance contained in
the vesicles is very small, and also that in all
perfect insects that pass the winter in a state of
hibernation the quantity of adipose matter is
much greater than in those which do not live
through the summer, while it has nearly all
disappeared in these insects after they have left
their hybernacula in the spring. We have
remarked these circumstances particularly in
the later broods of butterflies, which being
hatched at the end of autumn pass the winter
as hybernants and appear again in the spring,
and we have constantly noticed the same thing
in the large females of Bombus terrestris, which
live through the winter. From these circum-
stances there can be no doubt but that the
adipose matter is intimately connected with the

function of nutrition and the circulatory system,
while the free communication which we have
constantly observed to exist between the vesicles
seems to favour our opinion that they may
serve the office of lymphatic vessels. That
they cannot be supposed to answer the purpose
of a liver seems evident from the increase and
diminution of their contents at certain periods,
while their apparent connexion with the Mal-
pighian vessels seems to support the opinion we
have advanced, more especially if these be regard-
ed as uriniferous rather than as biliary organs.

Circulatory system. — It was formerly sup-
posed that there was a total absence of a circu-
latory motion of the fluids in insects^^tnd that
the whole body was nourished /by a simple
imbibition of fluids that occupied the cavities
of its different regions. This| opinion wag
strengthened by the circumstance of the air-
vessels being distributed to /every separate
structure and ramifying extensively even upon
the most delicate organs, a fa/ct so remarkable
that it appeared entirely to obviate the necessity
for a motion of the fluids, and led to the pro-
mulgation of Cuvier's beautifully ingenious
theory, that as the blood could not be carried to
be aerated in a separate organ or lung, the air
was in consequence brought into contact with
it throughout the whole body. But the dis-
covery of Carus in 1827 of an actual motion
of the fluids, and subsequently the discovery
by Straus Durckheim of a structure in the
dorsal vessel, which clearly indicates the true
use of this organ as a centre of circulation,
have sufficiently shown that insects do not
differ from other animals in the absence of a
circulation of their fluids, whatever modifica-
tions may exist in the form and situation of
the organs by which it is accomplished.

The heart or great dorsal vessel (jig. 433, A)
is an elongated tapering organ, which, in every
insect, occupies the middle line of the dorsal
surface of the body, and extends from the
posterior part of the penultimate segment of
the abdomen, through the thorax, into the first
segment or head of the animal. That portion
of it which is situated in the abdominal region
is the proper analogue of the heart of other
other animals, and is composed of a certain
number of separate compartments or chambers
(a). It is distinctly muscular, and is of con-
siderable diameter, and is that part which is
actively employed in circulating the blood.
The other part which extends through the thorax
is much narrower than the preceding, and is
not divided into chambers, but is one conti-
nuous vessel that becomes gradually narrower
as it passes through the thorax to the head,
where it is divided into separate branches (B).
This part is less actively employed than the
abdominal, being only the great vessel through
which the blood is sent from the muscular
heart to the system, and, consequently, repre-
sents the aorta. In the structure of the abdo-
minal portion or true heart we recognize three
separate coats, two of which are most distinctly
marked, and form the substance of the organ;
but the third or external one is very delicate
and not easily observed. Straus Durckheim
recognises but two distinct structures, the

INSECTA.

979

Fig. 433.

A, dorsal vessel or heart of Lucamis cerrus.

a, the valves or chambers ; b, b, the lateral mus-
cles ; c, the supposed auricular space around the
vessel.

B, the dirision into vessels of the anterior or aortal
portion of the dursal vessel in the larva of Vanessa \irt\cae.

C, interior of the dorsal vessel (Straus}.

a, interior of the valve, showing the transverse
fibres; 6, the auriculo -ventricular opening and
valve into the chambers of the vessel ; c, semi-
lunar valve ; d, inter-ventricular valve.

internal one (C, a) formed of a transversely
folded and striated membrane which is thickest
towards the middle of each chamber, and an
external one formed of strong, smooth, mus-
cular, longitudinal fibres. Burmeister* has
suggested that these may be only two layers of
one muscular structure, and that the presence
of a structureless lining or inner membrane
must then be presumed, although it be too
delicate to be actually detected by observation.
The third or external coat is a transparent struc-
tureless membrane which covers the outer

VOL. ii.

* Op. cit. p. 156.

surface of the heart, and is extended du t^e
over it without following the reflexions inwai -v
of the muscular coat, where it forms the valves,
or separations between the different chambers.
The division of the organ into separate cham-
bers is effected by means of an intussusception
or reflexion inwards and forwards of the whole
muscular structures. A portion of each side
of the heart is first extended inwards so as
very nearly to meet a corresponding portion
from the opposite side, and then reflected back-
wards forms, according to Straus,* the inter-
ventricular valve (d), which separates each
chamber from that which follows it. Posteriorly
to this valve, at the anterior part of each cham-
ber, is a transverse opening or slit (6), the
auricula-ventricular orifice, through which the
blood passes into each chamber, and imme-
diately behind it is a second but much smaller
semilunar valve (c), which, like the first, is
directed forwards into the chamber. It is
between these two valves on each side that the
blood passes into the heart and is prevented
from returning by the closing of the semilunar
valve. When the blood is passing into the
chamber the inter-ventricular valve is thrown
back against the side of the cavity, but is
closed, when, by the contraction of the trans-
verse fibres, the diameter of each chamber is
narrowed and the blood is forced along into the
next chamber. The number of these openings
and chambers in different species of insects
does not yet appear to have been satisfactorily
ascertained. Straus has figured nine chambers
in Melolontha, and consequently eight pairs of
openings, but we have not been able to observe
more than seven pairs of openings in Lucanus
cervus, in which the anterior pair is almost
hidden at the commencement of the aorta.
Burmeisterf states that he could not find more
than four pairs of openings in the larva of
Calosoma, while he remarks that according to
Muller's description of the heart in Phasma
there appears to be but one pair in that species.
In Bombus terrestris we have as yet detected
but five pairs, but we nevertheless suspect that
these discrepancies, or apparent differences in
the number of these openings, arise less from
so great a diversity in the actual number than
from some of them being overlooked during
dissection, since we have invariably found eight
pairs in Sphinx ligustri, both in the larva and
perfect state, as well as in other Lepidoptera;
while in the Bombus examined by us the
dissection was not so carefully made as to
enable us to state positively that there are not
more than we have mentioned. The external
form of the chambers in the very thick and
muscular heart of Lucanus is shown in the
drawing we have given of this structure. When
the heart is examined by transmitted light, there
is seen around it a bright space (A, c) in which
we have observed the blood flowing very freely
in living specimens afj&grum, and which we
regard with Straus as an auricular cavity,
apparently bounded by a loose membrane, and

* Considerat. &c. p. 356.
t Op. cit. p. 154.

3 S

976

! .ng backwards from the head and thorax

• and laterally from the sides of the abdomen.

We have observed a similar space in many

insects, particularly in Asilus crabroniformis

(fig. 434, D), and also in Bornbus terrestris.

Fig. 434.

One valve of the heart of Asiltts crabroniformis.
a, the chamber; b, the lateral muscles; c, the
auricular space ; the arrows denote the course of
the blood.

In this insect we have observed the fibres of
the heart crossing each other in an oblique di-
rection, forming as it were a series of festoons
around the posterior part of each chamber.
These, like the transverse fibres observed in
Melolontha by Straus, contract the diameter
of each chamber, and extend the vessel. Be-
sides the proper muscular structure of the heart
itself, there are attached on each side of the
organ several sets of muscular fibres, arranged
in pairs along the upper and under surface of
each chamber. Each set of these fibres, con-
verging to a tendon, and passing outwards,
forms a triangular muscle (A, b, 6), which
is attached to the lateral surface of each seg-
ment. These, which have been called the
wings of the heart, assist by their contraction
to shorten and expand the chambers at the
auricular, or receiving period of the heart's mo-
tions, while, as just explained, the transverse
and diagonal muscles occasion the ventricular,
by their contracting and narrowing the diameter
of each chamber. It is between the upper and
under set of the lateral muscles that we believe
'the auricular space to exist, bounded by a de-
licate membrane. The thoracic or aortal por-
tion of the heart commences at the anterior
part of the first abdominal segment, where the
organ bends downwards to pass under the
metaphragma, and enter the thorax. When it
has entered that region it immediately ascends
again between the great longitudinal dorsal
muscles of the wings, and passes onwards
until it arrives at the posterior margin of the
pronotum; it then again descends and con-
tinues its course along the upper surface of the
oesophagus, with which it passes beneath the
cerebrum, anterior to which, and immediately
above the pharynx, it is bifurcated and divided
into several branches, as formerly noticed by us
in the sphinx.* Previously to our notice, how-

Phil. Trans. 1832, p.

385.

INSECTA.

ever, Carus had seen the course of the blood
in the head of insects following directions cor-
responding to the situations in which we have
been able to trace a distinct division of the aorta
into vessels. We have found a similar division
of the aorta into branches in several species of
Coleopterous insects, as in Melue, Blctps, and
Timarc/ia, although we have omitted to trace
it in Lucanus, In the Sphinx and Vanessa
urtictf, immediately after the aorta has passed
beneath the cerebrum it gives off laterally two
large trunks, which are each equal in capacity to
about one-third of the main vessel. These pass
one on each side of the head, and are divided
into three branches, which are directed back-
wards, but have not been traced farther in conse-
quence of their extreme delicacy. Anterior to
these trunks are two smaller ones, which appear
to be given to the parts of the mouth and an-
tennae, and nearer the median line are two others,
which are the continuations of the aorta. These
pass upwards and are lost in the integuments.
The whole of these parts are so exceedingly
delicate that we have not as yet been able to
follow them beyond their origin at the termina-
tion of the aorta, but believe them to be con-
tinuous with very delicate circulatory passages
along the course of the tracheal vessels. It is
in the head alone that the aorta is divided into
branches, since throughout its whole course
from the abdomen it is one continuous vessel,
neither giving off branches nor possessing la-
teral muscles, auricular orifices, or separate
chambers. In the larva state it is far more
difficult to recognise the true structure of the
vessel by actual dissection than in the perfect,
because the valves are only in a rudimentary
condition. But it is easy to observe it in the
bodies of living transparent specimens, as done
by Carus, Wagner, Bowerbank, and others in
the Ephemeridtf and Agrionida, in which not
only the form of the valves and motions of the
vessel are distinct, but also the abundance of
globules that circulate in every direction. Even
in some of the opaque-bodied maggots of Dip-
tera we have seen the form of the valves very
distinctly through the tegument in the eight
posterior segments. When viewed in that state
each chamber appears to be much narrower at
its anterior and posterior extremity than in its
middle (Jig. 358, D), and the valves formed
by the reflexion of its parietes inwards, although
distinct, are very small. Near the middle of
each chamber there is attached on each side a
narrow muscle, which passing backwards is
attached to the anterior margin of each seg-
ment. Between the muscle and the heart in
each segment, a large tracheal vessel crosses to
anastomose with its fellow on the opposite side,
and on each side of the dorsal vessel, nearly
in the course of the lateral muscles, there is u
faint indication of a line which seems to form
the boundary of what we regard as the auricular
space in which the blood is collected before
passing into the chambers, of which there are
eight very distinct ones in these larvae.

The motion and course of the blood, as will
be seen from the above account of the structure
of the chief organ of the circulation, is first

INSECTA.

979

directly forwards in the middle line of the
body, and then backwards by the sides of the
thorax and abdomen, to the lateral and pos-
terior parts of the heart, into which it is re-
ceived, by means of transverse currents in each
segment, through the auricular space and ori-
fices. This course, as discovered by Carus, is
indicated in the description and diagram given
in a former part of this work.* The blood,
which is usually of a very transparent greenish
or yellowish colour, is filled with a great num-
ber of little particles, which were described by
Carus as oblong or oval, but more correctly
by Mr. Bowerbank f as flattened oat-shaped
masses, which retain their form while circu-
lating through the body, but like the particles
of blood in Vertebrata become globular imme-
diately they are brought into contact with water.
It is stated by Burmeister J that they vary in
diameter from" ^th to ,Lth of a line, but they
differ also in size in the same individual, and
are often rough or tuberculated as noticed by
£dwards,§ and as distinctly seen in the blood of
Sphinx ligu!>t?-i. The motions of the blood, ren-
dered perceptible by the presence of these par-
ticles, was first observed by Carus in the aqua-
tic larva of Ephemera, in which, as in other
aquatic transparent bodied larvae, the particles
are very distinct. Baker|| and some of the older
observers in this country had long before seen
motions of the fluids in the limbs of some in-
sects, but Carus first discovered the existence
of a complete circulation. Carus saw the blood
distributed in several streams from the aortal
extremity of the dorsal vessel in the head re-
turning in currents, that entered the base of the
antennae and limbs, in which it formed loops,
and then flowing into the abdomen entered the
heart at its posterior extremity. Wagner^] con-
firmed Cams' discovery, and added some new
observations. He saw the blood flowing back-
wards in two venous currents, one at the sides
of the body and intestine, and the other along-
side of the dorsal vessel, and he discovered
that the blood not only entered at the ex-
tremity of the dorsal vessel, but also at the
sides in each segment, at the valves discovered
by Straus. Both Carus and Wagner, however,
believed that the currents of blood observed
by them were not inclosed in distinct parietes
or vessels. Mr. Bowerbank,** in repeating these
observations, saw also the blood distributed by
the dorsal vessel forming loops in the antennae
and limbs, and then passing backwards in la-
teral and transverse currents, enter at the valves
into the dorsal vessel. And he also observed
and clearly defined the structure and action of
the valves. He discovered, however, that the
currents of blood along the sides of the body
are really inclosed in distinct parietes, and
do not flow in the common abdominal cavity,

* See Article CIRCULATION, vol. i. p. 652, fig.
325.

t Entomol. Mag. vol. i. p. 244.

j Op. cit. 404.

$ Art. BLOOD, vol. i. p. 408.

II On the Microscope, vol. i. p. 130.

\ Isis, 1832.

** Entomological Mag. vol. i. April, 1833, p. 239.

as previously supposed, the boundaries of the
vessels inclosing these currents being clearly
definable. He has also expressed his belief
that a " much greater portion of the circulation
than we can clearly define is carried on within
given vessels, as the blood may frequently be
seen flowing in curved and other lines, and con-
fined within very narrow limits, but so deeply
seated amidst the muscles and intestines as to-
tally to prevent the boundaries of the current from
being clearly observed." We are ourselves most
distinctly of the same opinion, having formerly,
through the kindness of Mr. Bowerbank, been
allowed to examine the circulation in Ephemera
by means of his powerful microscope. W7e
believe also that we have seen distinct vessels
passing transversely across the dorsal surface of
each segment, in the direction of the anterior
part of each chamber of the dorsal vessel,
in the large pupae of Acherontla Atropos and
Sphinx iigustri* but whether these are vessels
returning to or distributed from each chamber,
as we are most inclined to believe, is not cer-
tain. If they be not vessels distributed from
the heart, it is a somewhat curious circumstance
that the whole of the blood should be first sent
to the head of the insect, and the viscera of
the abdominal region be nourished only by the
returning blood, which has in part passed the
round of the circulation. The only instance
in which vessels had previously been supposed
to be distributed directly from the heart in the
abdomen was pointed out so long ago as 1824
by Professor Muller,f who discovered a con-
nexion of the oviducts with the inferior surface
of the organ in many insects ; but these were
afterwards believed by Carus, Treviranus,
Wagner, and Burmeister to be only ligamen-
tous connexions. W7e have observed these con-
nexions in many insects, and certainly believed,
when we first noticed them, without being
aware that they had previously been seen by
Miiller, that they were vascular structures. We
have traced them, especially in the Carabidte,
into direct connexion with the or°:an, but have
been unable to observe at what point the cavity
of the ovarial tubes commences, or where the
supposed ligamentous portion begins. We
have seen these connexions not only in the
perfect insects but also in the larvae, more espe-
cially in the males of Sphinx ligustri and
Odonestis potatoria. In these larvae the two
oblong testicles, not united into one mass as in
the perfect state, are each attached, side by
side, by two short filaments to that chamber of
the dorsal vessel which is situated in the ninth
segment. One of these attachments proceeds
from the anterior and the other from the pos-
terior part of each testicle. Now, if these at-
tachments be not distinct vessels, it is remark-
able that these glandular and secretory organs
should always be connected by mere ligaments
with the great circulatory organ, since, if the
object of their connexion were merely to retain
them in their place in the abdomen, it would

* Dr. Roget's Bridgewater Treatise, vol. ii.
p. 245.

t Nova Acta Nat. t. xii. 2.

3s 2

930

INSECTA.

probably be as well answered by an attachment to
any oilier part. These considerations certainly
lead us to hesitate to admit that they are mere
ligaments. Whatever be their nature, as MiiHer
has observed, their existence is indubitable.

Besides the parts now described, there is
also another which is connected with and
forms part of the vascular system, but the ex-
istence even of which has hitherto been almost
overlooked. This is a distinct vascular canal,
which is extended along the upper surface of
the abdominal portion of the cerebro-spinal
cord in perfect Lepidopterous insects, and
which we have traced from the thorax to the
termination of the cor.d. We have designated
this structure the supra-spinal vessel. It is
placed immediately above the cord, and is
covered by transverse muscular fibres, which
exclude it from the common abdominal cavity,
and give to the whole cord, when removed from
the body and examined by transmitted light,
a flocculent appearance. This appearance was
first noticed by Lyonet,* but the vessel between
it and the cord was not detected by him. It
was subsequently figured and described by us
in the Sphinx^ and the whole of our recent
observations J have confirmed the opinion we
then entertained of it. It is a most distinct
structure in the abdomen of the Sphinx, and
may be readily seen after the abdominal cord
has been carefully removed from the body with
its surrounding structures and placed for some
time in spirits of wine. We believe this vessel
to be the chief means of returning the blood
from the middle and inferior portion of the
body to the posterior extremity of the dorsal
vessel or heart, and that it is analogous to a
structure which we have found to be a supra-
spinal vessel § in the Scorpion and Centipede,
that had previously been supposed to be a
loose and easily detached portion of the nervous
system, but which is now proved to belong not
to the nervous but to the vascular structures.
We are strongly inclined to suspect that this
supra-spinal vessel in insects is connected with
the anterior portion of the dorsal vessel or
aorta, in a manner similar to the connexion
which was shown by Mr. Lord || to exist be-
tween the corresponding structure and the heart
in Myriapoda. (SeeMvniAPODA.) We believe
also that we have seen a corresponding vessel iii
the larva of the Sphinx, but of so delicate a struc-
ture as almost always to elude detection. It will
thus be seen that the blood certainly flows in
distinct vessels, at least in some parts of the
body in perfect insects, and that vessels exist
even in the larva. But although a circulation
of the blood has been seen by Carus, Wagner,
and others in many perfect insects, it has been
shown only in the appendages of the body, and
in those chiefly in recently developed specimens,
while it has been supposed to move only in in-

* Recherches sur 1'Anat. et Ics Metam. de diffe-
rcntes Especes d'Insectes. Paris, 1832, p. 505
pi. Iii. fig. 18. and pi. liv. fig. 2.

t Phil.Trans.p. ii. 1834, p.395, pi. xiv. fi?.9(a)

t Medical Gazette, March 17, 1838. D 973

$ Id. March 17, 1838, p. 971.

|| Id. March 3, 1838, p. 893.

tercel lular spaces and not in distinct vessels.
This opinion, however, is now invalidated by
our discovery of a supra-spinal or great ventral
vessel. A motion of the fluids has been seen
by Cams in the wings of recently developed
Libellulida:, Ephemera lutea, and E. niargi-
natUj and Clirysopa perla; among the Coleop-
tera in the elytra and wings of La/npi/ris italica
and L. splendidula, Melotonlha solstitialtt', and
Dyticus. But Carus was unable to detect it
in the wings of Orthoptera, although, accord-
ing to Humboldt,* Ehrenberg has seen it in a
species of Mantis, and Wagner in the young
of Nepa cinerea and Cimex lectuiarius among
the Hemiptera; but it has not yet been ob-
served in the Hymenoptera. Burmeister has
seen it in Eristalis tenax and E. nemorum
among the Diptera, and Mr. Tyrrelf in M-uaca
domestica as well also as in Geophilus and Li-
tlwbius forjicatus in the Class Myriapoda. In
addition to these Mr. Bowerbank has seen it in
one of the Noctuida; Phlogophora wcticu-
losa^ in the Order Lepidoptera, in which it
was seen also in the rodimental wings of some
pupae by Carus. Some of the most interesting
observations that have yet been made upon
the motions of the blood in these organs are
those of Mr. Bowerbank § in Clirysopa perla.
Mr. Bowerbank found that in the lower wing
of this insect the blood passes from the base
of the wing along the costal, post-costal, and
externo-medial nervures, outwards to the apex
of the organ, giving off smaller currents in its
course, arid that it returns along the anal or
inferior nervure to the thorax. He states that
the blood occupies the chief part of the cavi-
ties of these nervures, in each of the largest of
which is a very small trachea. From this
statement it has been rather hastily concluded
that the nervures of the wings are only venous
trunks, or passages for the circulatory fluids,
and are not formed, as hitherto supposed,
chiefly by ramifications of the tracheae. He
found tracheae existing in the larger of these
cavities, which measured only 22y.h of an inch
in diameter, while the cavities themselves mea-
sured ?ig of an inch ; but in others the tracheae
measured ig'inth, while the cavity measured only
sqgth. He states also that the tracheae very rarely
give off branches while passing along the main
nervures, and that they lie along the canals in
a tortuous direction. In consequence of these
most interesting observations we have examined
the wings of some dried specimens of this in-
sect, and have found that there exists, as Mr.
Bowerbank remarks, a very large and perfectly
transparent space around the tracheae, which is
more or less distinct in different specimens, but
in a few instances is not observable. But we have
invariably found that the tracheae not only exist
throughout the whole of the ramifications of the
wings, but also give off branches at every ner-
vure or space along which the fluid passes.

* Burmeister's Manual, p. 408.

t Proceedings of the Royal Society, Jan. 15,

} Entomological Magazine, vol. i. April, 1833,
p. 243.

$ Op. cit. vol. iv. Oct. 1836, p. 179, pi. xv.

INSECM.

981

Now the opinion to which we have been led by
our examinations of dried specimens, as we have
not been so fortunate as to obtain living ones,
since the commencement of these observations,
is, that every nervure contains a distinct tra-
cheai or air-bearing vessel, and that the free
transparent space by which it is surrounded,
and which is not discoverable by the naked
eye, but only by the microscope, constitutes
alone the proper circulatory passage; that the
tracheae, which are obvious to the naked eye,
do not simply lie loosely in these spaces, but
that the spaces lie chiefly at their sides and
under-surface. These opinions have been de-
rived from examinations of transverse sections
of the wings of the Chrysopa, at parts in which,
on a previous examination of the surface of
the wing, we have seen both trachea? and the
spaces around them. On cutting the wing
across at these parts, and then examining the
edges, we have invariably found the tracheae
hollow, unyielding tubes, while the free spaces
on each side, which appear as if bounded by
the upper and under membrane of the wing,
have appeared collapsed, and almost or com-
pletely closed, so as scarcely to exhibit any
appearance of hollow spaces. On examining
the wing of a dried specimen of one of the
Lepidoptera, Gonepteryx Rhamni, by trans-
verse sections, we have in every instance found
the nervures formed of hollow unyielding tubes,
with all the characters of true tracheal vessels,
but have not been able to detect the proper
circulatory spaces at the sides of these nervures,
most probably owing to their dried and col-
lapsed state. From these facts we are led to
express an opinion which has been long enter-
tained by us, that the course of the blood,
whether simply along intercellular spaces, or
bounded by distinct vessels, is almost inva-
riably in immediate connexion with the course
of the tracheae. This opinion is founded upon
the circumstance that nearly all the observations
that have hitherto been made have shown that the
currents of blood in the body of an insect are
often in the vicinity of the great tracheal vessels,
both in their longitudinal and transverse direc-
tion across the segments,and it is further strength-
ened by Mr. Bowerbank's observations on the
course of the blood in the wings. During his
observations Mr. Bowerbank observes that he
" has used every endeavour to discover, if pos-
sible, whether the blood has proper vessels, or
only occupied the internal cavities of the ca-
nals ; and that he is convinced that the latter is
the case, as he could frequently perceive the
particles not only surrounding all parts of the
tracheae, and occupying the whole of the in-
ternal diameter of the canals, but it frequently
happens that globules experienced a momen-
tary stoppage in their progress, occasioned by
their friction against the curved surface of the
tracheae, which sometimes gave them a rotatory
motion." He remarks also that the usual course
of the blood through the canals is in one conti-
nued stream, without pulsatory motion, ex-
cepting only when the insect under examination
is struggling to escape, when the continuity of
the stream is broken, and there are occasional
oscillations, n which he observed, iu one in-

stance, in a vessel within a space ot about one-
fiftieth of an inch, twenty-one oscillations in a
minute ; and in another, in the same space, so
many as eighty-four. He observed also in in-
sects that had been captured and in confine-
ment for several days, that the motions of the
fluid became exceedingly languid and almost
entirely ceased. Thtse observations are exceed-
ingly interesting in reference to the general
velocity of the circulation, and the means by
which it is carried on in the wings. The entire
absence of pulsations is remarkable, as it com-
pletely identifies these vessels as veins, since it
is well known that the circulation is carried on
through the body by means of regular pulsa-
tions of the dorsal vessel. The number of these
latter pulsations varies greatly in different insects.
Thus Herold found from thirty to forty in a minute
in a full-grown caterpillar, and from forty-six to
forty-eight in a much younger one; Suckow ob-
served but thirty, in the same space of time, in a
full-grown caterpillar of Gastropacha pini, and
eighteen only in its pupa state. But in one in-
stance, when the insect was in a state of the most
violent excitement, we have counted one hundred
and forty-two in a female of Anthopkora re-
tusa. In a number of these insects captured
just after they had left their hybernacula in the
month of April, and confined for some time in
a breeding-cage, we have found that the num-
ber of pulsations varies, as might, a priori, be
supposed, according to their state of excite-
ment. Thus on exposing the dorsal vessel in
the morning, before the insects had been excited,
we found the number of pulsations was about
eighty per minute ; at ten o'clock, when they
had become active, the number of pulsations
ranged from one hundred to one hundred and
ten ; but at three o'clock in the afternoon, when
the insects were quite lively, and had been
exposed to the sun for an hour or two, the
number of pulsations amounted to one hundred
and forty; while on another occasion, on a cold
dull morning, when the bees were languid, the
number of pulsations did not exceed seventy-
five in any specimen that was examined. It
has usually been supposed, since the discovery
of a circulation in insects, that the pulsations
are more frequent in the larva than the perfect
state ; but this certainly is not the case, if the
mean number of observations in the two states
be compared. Thus in a series of observations
made by us on the Sphinx ligustri,* from the
fourth day after the larva had left the egg until
the perfect insect was developed, it was found
that before the larva cast it&Jirst skin the mean
number of pulsations, in a state of moderate
activity and quietude, was about eighty-two or
three per minute ; before casting its second skin
eighty-nine ; while before casting its third it
had sunk down to sixty-three ; and before its.
fourth to forty-five, while previously to leaving
its fourth, and before it had ceased to feed, pre-
paratory to entering the pupa state, it was not
more than thirty-nine. Thus the number gra-
dually decreases during the growing larva state,
but the force of the circulation is very much
augmented. Now when the insect is in a slate

* Phil, Tians. p. 2, 1837.

982

INSECTA.

of perfect rest, previously to changing its skin,
the number is pretty nearly equal at each pe-
riod, being about thirty. When the insect
has passed into the pupa state it sinks down to
twenty-two, and subsequently to ten or twelve,
and after that, during the period of hybernation,
it almost entirely ceases. But when the same
insect which we had watched from its earliest
condition was developed into the perfect state
in May of the following spring, the number of
pulsations, after the insect had been for some
time excited in flight around the room, amounted
to from one hundred and ten to one hundred
and thirty-nine; and when the same insect was
in a state of repose, to from forty-one to fifty.
When, however, the great business of life, the
continuation of the species, has been accom-
plished, or when the insect is exhausted, and
perishing through want of food or other causes,
the number of pulsations gradually diminishes,
until the motions of the heart are almost im-
perceptible. Insects, then, do not deviate from
other animals, as has been supposed, in re-
gard to their vital phenomena, although it has
been somewhat curiously imagined that the
nutrient and circulatory functions are less
active in the perfect than in the larva condition.
This supposed inferiority has been attempted
to be accounted for on the hypothesis that as
insects no longer increase in size after entering
the perfect state, there is but little expendi-
ture or waste of body, and that, consequently,
they must require less nourishment. But we
have elsewhere shown * that the expenditure of
the body, whether in the larva or perfect state,
is in the ratio of the amount of activity and
length of life of the insect, while it will be
remembered that those insects which exist but
for a short time in the perfect state, and take
little or no food, invariably have a supply
of nourishment stored up within their own
bodies, in immense accumulations of adipose
matter; and that those which exist for a long
period have within themselves only a small
quantity of nourishment, but are by no means
sparing in the quantity of food daily consumed
by them, being, as they often are, some of the
most voracious of the insect race.

Organs of respiration. — All perfect insects,
whether inhabitants of air or water, breathe air
alone; but some larvae, that are constant in-
habitants of water, respire the air which is me-
chanically mixed with the water, by means of
branchiae ; but respiratory organs in the form of
tracheae (Jig. 435) are almost as extensively
distributed throughout every part of their bodies
as in the perfect insects. We shall divide the
respiratory organs into external and internal.
The external are of three kinds, spiracles, tra-
chea, and branchia. The internal are either
simply trucheal, or tracheal and vesicular.

The spiracles are apertures situated along the
sides of the body communicating directly with
the internal respiratory organs. They are
usually nine in number on each side. In Hy-
menopterous larvae there are ten. Each spi-
racle consists of a horny ring, generally of an
oval form, within which is a valve formed of a

* Phil. Trans, p. 2, 1837.

Fig. 435.

Portion of a tracheal vessel of the larva of Vanessa
urtices, shewing, a, the spiral fibre ; and 6, the
loose investing covering. {Newport, Phil. Trans.)

series of converging fibres, and which opens
perpendicularly in its long axis, guarding the
external entrance. At a little distance within
this valve the spiracle is somewhat enlarged,
and there is a second valve of a more com-
plicated form. This has already been noticed
in our account of the muscular structure, but
we must again describe it in connexion with the
respiratory organs. The anterior half of this
inner or second valve is strong, immovable,
and of a horny texture, of the colour of tortoise-
shell. It is thin and lunated at its margin.
The posterior half is thick, rounded, and freely
moveable, and closes on the anterior like a
cushion or pad. This is the structure of the
spiracle in the Sphinx and most other insects.
But in some, in which the spiracle is concealed
beneath a portion of the skeleton, the horny
external ring is absent, and instead of it the
entrance, or margin of the spiracle, is merely a
little thickened and fringed with short hairs.
This description of spiracle exists in the pro-
thorax of some Coleoptera and Orthoptera
as in Gryllotalpa, in which one portion or lip
overlaps the other, thus forming as it were an
outer valve or lid. In other instances, as in the
Lamellicornes, the spiracles of the abdomen
are very minute and circular, and their open-
ing appears to be cribriform, or at most only
very minute, and surrounded by short hairs.
In others, again, as in some larvae, the spiracles
consist of a broad margin with a narrow
middle space and central aperture that leads
immediately into the tracheal vessel, the open-
ing into which is exceedingly small. The size
of the spiracles in different parts of the body
varies very much in different insects. Those
of the abdomen are always much smaller than
those of the thorax, and the most posterior ones,
which were of great importance in the larva

INSECTA.

983

state, are almost or entirely imperforate in the
perfect. The reason for this appears to result
from the changes that take place as regards
the region of the body in which respiration
is chiefly carried on in the two states of
the insect. In the larva state respiration is
carried on chiefly in the abdominal region, but
in the perfect the chief part of the body con-
cerned is the thorax. It is through the tho-
racic and first pair of abdominal spiracles that
nearly the whole of the air enters and is ex-
pired at each act of respiration, and conse-
quently it is found that the spiracles in those
parts are very much larger than in the abdo-
men. The largest spiracle is usually the pro-
thoracic, of which we have an example in
Geotrupes and Gryllutalpa, and the next
largest, as in Geotrupes, is the first abdominal.
The situations in which the spiracles are placed
also vary considerably in different insects. In
Coleoptera and Orthoptera the first pair are si-
tuated in the membrane between the pro- and
meso-thorax, and the remaining ones in the
meso-* and meta-thorax and following seg-
ments of the abdomen. There is also a similar
arrangement of the spiracles in Hemiptera.
But in other insects, as in the larvae of Lepi-
doptera, the first spiracle is situated in the pro-
thorax, and the remaining eight pairs in the
fifth and succeeding segments to the twelfth ;
while in the larvae of Hymenoptera, in which
there are ten spiracles on each side, they are
placed in the second, third, fifth, sixth, and
succeeding segments to the twelfth.

The second form of external respiratory or-
gans, as Burmeister remarks, are simply elon-
gated spiracles, and are found only in those
insects which reside almost constantly in the
water, but breathe pure atmospheric air, for
which purpose they come to the surface of the
water at intervals to respire. They are short
horny tubes, which in some instances are sur-
rounded by plumose setae. They are always
open at their extremity, and in general project
beyond the body. They are chiefly met with
in the aquatic Hemiptera, as in Nepa (Jig.
352) and Ranatra, and are usually two in
number, projecting from the extremity of the
abdomen. In Nepa they are about half the
length of the body, and in Ranatra as long as
the whole body itself. It is through these
tubes that the whole of the respiratory function
is performed, and the air both inspired and ex-
pelled. They exist also in the larvae of the
DyticidtE and Hydrophilidtf, in which they
are the only respiratory passages, although it
has been thought by some that lateral spiracles
exist also in these larvae, as subsequently found
in their perfect insects. This form of respira-
tory organ exists also in the aquatic larvae of
some Diptera, as in the rat-tailed maggot,
Eristalis, and the larva of Stratiomys. In the
latter instance the insect supports itself at the
surface of the water by a coronet of radiating
setae, in which it includes a bubble of air, and
descends with it to the bottom of pools for
the purposes of respiration, and comes again

* Straus.

to the surface for a fresh supply when the store
it has carried with it is exhausted. These or-
gans are thus distinct from those by means of
which the insects respire the air mechanically
mixed with the water.

Bronchia constitute the third form of ex-
ternal respiratory organ. This form is met
with only in the larva and pupa state. These
organs are always situated at a part of the body
at which the spiracles are subsequently to exist.
They are formed, as in the larvae of Amphibiae, of
extensions outwards of the exterior or cuticular
surface of the body, and are largely supplied
with bloodvessels, and tracheae ramify within
them. They are never, as in the gills of fishes,
developed internally, excepting when they exist
at the anal extremity of the body, as in the
Libellulidte, but are extended from the sides as
in the Tadpole, being simply expansions of the
external surface. \Ve are not aware that cilia
have yet been observed on these surfaces, but
judging from the analogies of structure and
formation that exist between these parts in
insects and the analogous ones in the larvae of
Amphibia, there seems reason to expect that
they do probably exist. The necessity for such
structures on the branchiae may, however, be
rendered less imperative from the voluntary
power which the insect itself possesses of
moving the branchiae at pleasure, by which
the function of cilia, that of effecting a con-
stant renewal of the water in contact with the
surface of the organ, is steadily accomplished.
It is the belief of most entomologists,* that
branchiae absorb the air from the water, and
convey it by the minute ramifications of the
tracheal vessels, with which they are abundantly
supplied, and which terminate in single, trunks,
into the main tracheae, to be distributed over
the whole body, as in insects which live in the
open atmosphere. This is supported by the
fact that the tracheal vessels, as seen in the
transparent bodies of many aquatic larvae, are
filled with air; but the subject still admits of
enquiry, why in these instances the usual func-
tion of branchiae is so far departed from as to
allow of the air being absorbed from the water
into distinct vessels, to be distributed over the
whole body, for the purpose of aerating the
fluids, rather than that it should be brought
into contact with the blood, and undergo the
consequent changes at the surface of the bran-
chiae, as in the larvae of Amphibia and Fishes.

The branchiae of insects are of three kinds.
The first exists in the form of elongated,
slender, hair-like organs, collected together in
tufts, that originate by single stems, as in the
larvae and pupae of gnats. f This form is by far
the most common. These filamentous parts
are supplied each with a single trachea that is
extended throughout their whole length, and
which is connected with the great longitudinal
tracheae of the body. In a very few instances,
branchiae of this form originate separately, and
not in tufts, as, according to De Geer,| in the

* Burmeister.

t Burmeister, op. cit. p. 167.
t Memoires sur les Insectes. vol. iv. pi. 13,
fig. 16.19.

984

INSECTA.

larva; of Gyr initial, in which they are arranged
along the sides of each segment as short stiff
bristles. This form of branchiae is also said to
exist in one solitary species of Lepidoptera,
Hydrocampa stratiotatu* and perhaps, also,
in the other species of the same genus, in
•which branchiae of this form exist in the neigh*
bourhood of false spiracles.

The second kind of branchiae exists in the
form of flat, oval, or lanceolate plates, extended
from the sides of each segment of the abdo-
men, where spiracles afterwards exist in the
perfect insect. In some instances, as in the
Agrionidte, these plates exist only at the extre-
mity of the abdomen. In others, as in the
Ephemerida, they exist both at the sides and at
the extremity of the body. This form of
branchiae is found only in the Neuroptera and
Trichoptera. In many of the latter instances
these parts possess also the additional function
of being the chief locomotive organs of the
insect, and remind us strongly of the branchi-
form organs of locomotion in the post-abdo-
men of many Crustacea.

An anomalous insect, recently discovered by
Mr. Hogg as a constant inhabitant of the river-
sponge, and an account of which was read by
Mr. Westwood at a meeting of the Entomolo-
gical Society on the 3rd of December, 1838,
possesses a third and most remarkable descrip-
tion of branchia. This insect, which was re-
ferred by Mr. Westwood to the order Neurop-
tera, genus Acentropus, STEPH. very much
resembles the larva of a neuropterous species,
and has filiform branchiae extended from the
sides of the abdomen, which are distinctly or-
ticuluted, and apparently five-jointed, Mr.
Westwood informs us that he has distinctly
traced tracheae into the branchiae, and that the
open extremity of each vessel protrudes from
the tip of the branchiae, so that in this respect
these organs resemble elongated spiracles.

Very few of those larvae or pupae that pos-
sess branchiae have any lateral spiracles, ex-
cepting the Culicidte. In some of these, as in
the common Gnat, both larvae and pupae breathe
by means of large tracheal vessels, extended
outwards to some distance from the head and
thorax, while the body is also furnished with
filamentous branchiae. The larva of Chiro-
nomus, remarkable for its blood-red colour, and
which breathes through tubes, is furnished in
its pupa state with branchiae f at a part cor-
responding to that at which the first spiracles
are to appear in the perfect insect. The true
Libelluuda have neither lateral nor anal bran-
chiae, but, according to Suckow and others,
breathe by means of branchiae in the colon.
But in these insects, as in the Ephemerida
with lateral branchiae, the acts of respiration are
also those of progression ; since, although the
imbibition and expulsion of water at the anal
extremity are regular and constant, even when
the insect is remaining perfectly quiet, they are
increased both in number and force at every
act of locomotion, and carry the body forward

* Id. vol. i, pi. xxxvii.
t Burnaeister, p. 167.

by darts or sudden impulses. Tlte water is
received at the anal orifice by an inspiratory or
sucking action, as proved by the circumstance
that small particles of substances floating in
the water are drawn in with the stream at the
anus at each inspiration, and again expelled
from it when the water is ejected, and this oc-
curs with the greatest regularity. The cavity
into which the water is received is a cloaca
distinct from the proper alimentary canal,
analogous to the respiratory cloaca of the Ho-
lothuria and other lower invertebrata.

These external organs of respiration all com-
municate with elongated tracheae, from which
are distributed other branches over the internal
structures. In the larvae of all insects these
internal respiratory organs are simply ramified
tubes, but in perfect insects, and more parti-
cularly in volant species, these tubes are di-
lated into an immense number of minute
vesicles, which not only allow of the most ex-
tensive respiration, but also render the body
lighter, by enabling the insect to alter its spe-
cific gravity during flight. In all insects the
vesicles are only dilated tracheae, the structure
of which is the same throughout the class. In
the larva of the Sphinx and other insects the
tracheal vessels consist of two elongated tubes,
extended one on each side of the body, and
which on their external side communicate by
very short tubes with the spiracles, and on their
opposite, towards the middle line of the body,
give off near each spiracle a large tuft of ves-
sels, about twelve in number, which extending
inwards are distributed over the different
organs within the body. The chief of these
are distributed to the alimentary canal, while
others pass upwards among the muscles, and
ramify most extensively between them, and are
given in great abundance to the dorsal vessel.
In every segment other branches are extended
to the median line above the vessel, and anas-
tomose with corresponding branches from the
opposite side of the segment. In the head one
large branch passes forwards from the pro-
thoracic spiracle, and anastomoses with its
fellow from the opposite side above the oeso-
phagus, behind the brain, and the two thus
united then give off four branches, which
passing forwards over the brain give off branches
that ramify on the surface, and even in the
substance of that organ and of the optic
nerves. Other branches are given to the
muscles of the head, the future antennae, and
the organs of manducation. On the under
surface of the body the tracheal vessels dis-
tribute themselves among the muscles, as on
the dorsal surface, some passing beneath the
nervous cord to anastomose with those from the
opposite side, while others are distributed to,
and ramify extensively over the surface of each
gangliated portion of the cord, giving off the most
minute branches which penetrate the very sub-
stance of the ganglia (fig. 415, i, i), and also
that of the nerves themselves, along which other
minute branches are extended, so that even the
most important and delicate organs of the
body are plentifully supplied with tracheal
vessels. Other branches of tracheae also pass

1NSECTA.

between the fibres of the muscular coat of the
alimentary canal, and ramify extensively be-
tween the mucous coat and a structure which we
have described* as the adipose coat, which lies
between the mucous and muscular, as is well
seen in the colon and crecum of the puss-moth,
Centra vinula, in the perfect state. It is in
this layer that the ramifications of trachea
anastomose very freely, but do not enter the
mucous or internal coat. Besides these parts
all the secretory and generative organs are sup-
plied with anastomosing branches in abun-
dance, and tracheae are extended even to the
very last joints of the tarsi in the limbs. The
only parts into which we have not observed
tracheae penetrate are the adipose vesicles,
upon which we have not often observed rami-
fications, although branches of trachese are dis-
tributed very extensively among them. In the
larva state the trachese are always smaller than
in the perfect, compared with the size of the
individual, and they are smallest in those
apodal larvae of Hymenoptera which reside
long in closed cells, as the Anthophora return,
in which insect the communications of the
trachese across the body are very distinct, as
was shewn long ago by Swammerdam in the
larva of the hive-bee.

The structure of the tracheae has been des-
cribed by Swammerdam, Sprengel, and others.
Sprengel has described the structure as con-
sisting of an external serous and an internal
mucous membrane, inclosing between them a
spirally convoluted fibre (JigA35, a\ which is
elastic, and gives to the tracheae the appearance
exhibited by the tracheae in other animals.
The external or serous membrane (6) very
loosely surrounds the spiral fibre («). The
mucous or internal lining, as we formerly re-
marked, and as noticed by Swammerdam, De
Geer, Lyonet, and Bonnet, is continuous with,
and is thrown off at the change with the external
covering of the larva, and certainly is a distinct
membrane, renewed at those periods, although
Sprengel believes that it is only a means of
connexion between the coils of the spiral fibre,
and not a distinct structure.

The vesicles, or dilated trachese, exist in the
greatest abundance in volant insects, although
they also exist in a much less developed form
in the saltatorial. These vesicles exhibit an
appearance which was formerly noticed by
Swammerdam in Oryctes nasicomis, and sub-
sequently by Sprengel in other insects. It con-
sists of an amazing number of punctured spots,
discoverable only under a good microscope, but
which, when attentively examined, exhibit
somewhat the appearance of perforations. The
precise nature of these spots is not well under-
stood. Burmeister conceives that they are oc-
casioned by the rupture of the spiral fibre
during development, and that the spots are the
spaces between the broken fibres. But Marcel
de Serres and Straus Durckheim deny the
existence of spiral fibre in the vesicles, while
Suckow and Burmeister contend that it cer-
tainly does exist, and we also are of this

* Phil. Tians. 1836.

opinion. Indeed, when it is remembered that
the vesicles exist only in the perfect insect, and
are only dilated tracheae, and that the existence
of spiral fibre in the tracheae is undoubted,
surely its existence can scarcely be questioned
in the vesicles, although, probably, it is in an
almost atrophied condition. Now the fact that
the spots are not observed on the vesicles
until the insect has entered the perfect state,
was, perhaps, one of the circumstances that
led Burmeister to his opinion respecting them ;
but that they are not caused by ruptured spiral
fibre is proved by the existence of these spots
in some of the tracheae that communicate direct-
ly with the vesicles, and have not been dilated,
and in which the spiral fibre is unbroken. It
is also shewn by the circumstance of their not
being in a regular series, over the course of the
fibres, but distributed thickly and irregularly
over the surface of the vesicles, and by their
existing in the space between two parallel
fibres in the trachese, and even in the substance
of the fibre, as we have seen them in the
vesicles of the male of Bombus terrestris. Be-
sides this, they are sometimes seen to terminate
in an abrupt and remarkable manner in the
dilatations of the larger tracheae in the same
insect. The results of our own observations
lead us to conclude that these spots are not
ruptures of the spiral fibre, but are partial per-
forations of the vesicles, — that they do not
pass through the internal or lining coat, and
probably are little cells in the coats of the vesi-
cles, through which the circulatory fluid can be
freely submitted to the action of the air in the
vesicles, as in the minute terminal cells in the
lungs of vertebrata.

The use of the vesicles, as above remarked,
and as formerly suggested by Hunter, appears
to be to enable the insect to alter its specific
gravity at pleasure, by enlarging its bulk, and
thus rendering it better able to support itself on
the wing with little muscular effort. That this
is the use of the sacs may be inferred from
their non-existence in the larva state, or in in-
sects that constantly reside on the ground, more
particularly in creeping insects ; and it seems
further confirmed by the fact that, among volant
insects, those have the largest and greatest
number of vesicles which sustain the longest
and most powerful flight. Thus the vesicles
are found most developed in the Hymenoptera,
Lepidoptera, Diptera, and some Coleoptera and
Hemiptera, in all which, in the larva suite, there
is not the slightest trace of them. A still
further proof that they are for lightening the
body is found in Lucanus cervus. In the
male of this insect the large and heavy man-
dibles and head, but more especially the man-
dibles, are not filled with solid muscle, as in
the Hydrous and others in which these parts
are more in proportion to the size of other
parts of the body, but with an immense
number of vesicles, which in the mandibles
are developed in the greatest abundance in
rows from long tracheae, that are extended
from one end of the organ to the other, so that
the interior is almost entirely filled with vesi-
cles. By this beautiful provision these pro-

INSECTA.

jecting and apparently unwieldy structures
are rendered exceedingly light, while their
solid exterior fits them for all the purposes of
strength required by the insect. The large and
apparently heavy body of the humble-bee is
lightened in a similar manner. In this insect
and others of the same order, the vesicles are
fewer but very much larger than in Coleoptera.
The lateral tracheae in the abdomen form one
continuous chain of dilatations, which are
larger in the males of the species (Jig- 436)

Fig. 436.

The lateral and inferior series of vesicular respi-
ratory organs in the abdomen of a male individual of
Bombus terrestris. (Newport, Phil. Trans.)

than in the females. The longitudinal tra-
cheae (a), that pass backwards from the
thoracic region, are connected just as they
pass through the petiole or thoracico-abdo-
minal segment into the abdomen, by a very
short transverse branch (b), which gives off
two pairs of minute branches into the ab-
domen. The longitudinal tracheae (c) pur-
suing their course onwards are dilated, soon
after they enter the large first segment of the
abdomen, into two enormously expanded
vesicles (/*), above which is placed transversely
a third and much larger one, which is formed
from the anastomosing branches of the opposite
sides of the segment, and is also connected
with the little branches given off from the
transverse branch (ft). Beneath this large
vesicle passes the dorsal vessel, and between
the tv\o lateral ones (/") the alimentary canal.
Besides the branches from the transverse trachea?
(6) there are two others from the large tra-
cheae (c), which pass longitudinally backwards,
one on each side of the oesophagus. That on
the left side (e} e) passes as far as the posterior

part of the proventriculus, and then turning
forwards distributes its branches to that organ.
The other on the right (d, d) extends no farther
than the anterior part of the proventriculus,
immediately behind the crop or honey-bag,
upon which it is chiefly distributed. The large
vesicle (J") is connected with the dilated
tracheae in the succeeding segments, and the
whole form one continuous irregularly-shaped
vesicular cavity, which, along its under surface
in each segment, is dilated into a funnel-shaped
transverse trachea (g), that anastomoses with its
fellow of the opposite side, passing beneath
the muscles as in the larva. From the upper
surface of the longitudinal canals similar fun-
nel-shaped dilatations (i, k) pass over the
dorsal surface of the abdomen and anastomose
in like manner with those of the opposite side,
besides which single undilated ramifications of
tracheae (//) pass inwards on each side and are
distributed over the alimentary canal. At the
posterior part of the body the vesicular canals
communicate directly by a large branch (/),
from which large trunks are given to the colon
and organs of generation. Thus, then, the
use of the vesicles is distinctly indicated, even
in the peculiar distribution of undilated tracheae
to the whole of the organs of nutrition. The
distribution of single ramified tracheae from
large vesicles appears to be constant in this
order ; it was formerly shown by Leon Du-
four* in Scolia hortorum, and we have always
found it in the Ichneumonida; and other fami-
lies. Burmeister states that he has been un-
able to ascertain whether this is also the case in
Diptera, in which order the vesicles are both
large and numerous. According to Marcel de
Serresf the Asilida; have an immense number
of small elongated vesicles on each side. In
one species they amount to so many as sixty.
Burmeister remarks]; that, in Lepidoptera, the
vesicles in the Sphingida and moths are chiefly
found in the males, which agrees with our own
observations in Hymenoptera. In Acherontia
Atropos he states also that the existence of
spiral fibre in the vesicles is so distinct as not
to be doubted.

This is the structure of the respiratory
organs in volant insects, but throughout the
class, whether in volant or creeping insects,
there is always a complete anastomosis of the
tracheae on one side of the body with those on
the opposite, as has been well exemplified by
almost all insect anatomists, Swammerdam,
Lyonet, Marcel de Serres, Dufour, Straus, and
others.

The development of the vesicles begins to
take place at about the period when the larva
ceases to feed, preparatory to changing into the
pupa state. At the time when the larva of the
Sphinx enters the earth, and is forming the cell
in which it is to undergo its transformation,
the longitudinal tracheae of the second, third,
fourth, and fifth segments become a little en-
larged. In the butterfly, Vanessa urtic&y
which does not enter the earth, but suspends

* Journal dc Physique, Sept. 1830.

t Mcmoires dcs Mus6um, torn. iv. p. 362.

j Op. cit. p. 181.

CTA.

967

itself vertically to mndergo Us change, the di-
latation commences while the insect is spinning
the silkeu hangings from which it suspends
itself; so that the changes commence at a
corresponding period in both insects. It is in
the butterfly that we hare most closely watched
the development of the vesicles. During the
period that the insect remains suspended it
makes several powerful respiratory efforts,
accompanied by much muscular exertion, and
these efforts are continued at intervals until the
old skin is fissured and thrown off. It is at
this period that the tracheae become much en-
larged, as we have found at about two hours
after the insect has suspended itself. Meckel
observed the sacs soon after the insect has
entered the pupa state, but it will thus be seen
that the expansion of the tracheae in the for-
mation of these sacs commences very much
earlier. At about half an haxr before the in-
sect becomes a pupa we have found the whole
of the tracheae more distended, particularly
those on the under surface of the thorax, from
which branches are given to the legs, so that
the elongation of these tracheae is probably
connected with the subsequent rapid develop-
ment and extension of those organs. At this
period the trachea! of the abdomen have ex-
perienced but little alteration. It is at the
actual period of transformation that all the
changes take place most rapidly. At that time
the laborious respiratory efforts made by the
insect appear greatly to affect the condition of
all the organs. When the skin is thrown off,
these efforts cease for a few minutes, after
which the abdominal segments become short-
ened, and the circulatory fluid is propelled
forwards, and the wings, then scarcely so large
as hemp-seeds, are gradually distended at their
base, and at each respiration are perceptibly
enlarged, and carried downwards over the under
surface of the thorax and first abdominal seg-
ments. Carus* attributes the development of
the sacs, and dilatation of the tracheae, to the
entire closing of the spiracles, and expansion
of the air contained within them, which he
thinks is increased in quantity during the deve-
lopment of the insect. But from the circum-
stance that all the tracheae are enlarged imme-
diately after the insect has entered the pupa
state, it seems probable that this enlargement
is occasioned simply by the closing of the
spiracles, and the expansion of the air within
the trachea?, during the powerful respiratory
efforts, aided by the receding of the circulatory
fluid from the abdomen into the partially de-
veloped wings, suddenly removing pressure
from the trachea! tubes, which then become
distended by the natural elasticity of the air
contained within them ; and further, that the
subsequent enlargement of these tracheae into
distinct bags is occasioned, not by an in-
creased quantity of air in the vesicles, as
Cams imagines, but simply by a continuance
of the same cause that effects the first dila-

* Introduction to Comparative Anatomy,
lated by Gore, 1827, vol. u. p. 167.

tation of the trachea?, the elasticity of the
contained air, since the dilatation appears to
keep pace with the gradually decreasing site
of the digestive organs, and the spiracles are
not permanently closed during the pupa state,
respiration being continued at intervals, ex-
cepting perhaps in the most complete state of
hyberuation. In accordance with this opinion
we find that, at about halj am hour after the
change, the pro-thoracic tracheae that ramified
over the oesophagus are enlarged to double
their original diameter, and have begun to be
detached from that organ. At seven boms
these changes have been carried much farther.
At twelve hours they are still further enlarged,
and the principal alteration observed is the
diagonal direction of those from the seventh
spiracles, which supply the posterior extremity
of the digestive stomach, owing to that organ
having now become shorter, previously to its
subsequent change. At eighteen hours all the
tracheae of the head and thorax are still further
enlarged, and those from the third spiracle are
detached from the cardiac extremity of the
stomach, and are more enlarged than the others,
and those from the ninth spiracle, in the twelfth
segment, which supply the colon, are begin-
ning to be distinctly vesicular. At thirty-sir
hours not only have the longitudinal tracheae
and their many branches become dilated, but
those distributed to the different viscera have
also become vesicular. At forty-eight hours
the development of these parts is so far ad-
vanced that the whole have assumed the vesi-
cular form, and those at the anterior part of the
abdomen occupy a great proportion of that
region, and the dilatation of others proceeds
until within a few days before the perfect insect
is developed, before it is completed. The
only difference we have observed between the
development of these organs in the Sphinx
and the butterfly is in the rapidity with which
the changes are effected. The Sphinx re-
mains many months in the papa state, during
a great part of which time die changes are
almost or entirely suspended. The butterfly
remains but a few
all the chj

days, and in consequence
eed with rapidity, which is

either greater or less in proportion to the
of the year and temperature of the atmosphere.
function of respiration. — Having dwelt so
long upon the structure of the parts concerned
in respiration we cannot venture at any length
upon the phenomena connected with tne^aatr-
rum, which properly belong to a distinct sub-
ject. (See RESPIRATION.) We would remark,
however, that the circumstances connected
with it are in many respects particularly in-
teresting, while the results are similar to those
of the respiration in other air-breathing ani-
mals. Thus the acts of respiration consist of
alternate dilatations and contractions of the ab-
dominal segments, the air entering the body
chiefly at the thoracic spiracles, and partly also
at the abdominal, during which the dorsal and
ventral arches of the abdomen are alternately
elevated and depressed, like the ribs of
tebrata. The number and frequency of these

988

INSECTA.

respirations vary, as in Vertebrata, according
to the degree of activity and state of excite-
ment of the insect. Thus when an insect has
been subject to long-continued exertion, the
acts of respiration are quick and laborious, as
every one must have observed in the larger
Bombi, when alighting after a long-continued
flight. The contractions and extensions of the
abdominal segments are then short and quick,
and sometimes so labored that the whole ab-
domen is shortened and extended like the
flanks and ribs of the race-horse, after a long
and severely contested race. The number of
respirations, when the insect is in a state of
moderate excitement, "varies also in different
species as well as in the different states of the
same insect, and at different periods. Thus in
the, green grasshopper we have noticed from
thirty to forty regular contractions in a minute,
alternating, at irregular periods, with others
more long and deep than the rest. When this
insect was much excited the intervals between
the long inspirations were longer, and the in-
spirations when they occurred were more deep
and laborious. When an insect is preparing
itself for flight the act of respiration resembles
that of birds under similar circumstances.
At the moment of elevating its elytra and ex-
panding its wings, which are, indeed, acts of
respiration, the anterior pairs of spiracles are
opened, and the air rushing into them is ex-
tended over the whole body, which, by the ex-
pansion of the air-bags, is enlarged in bulk,
and rendered of less specific gravity, so that
when the spiracles are closed at the instant the
insect endeavours to make the first stroke with
and raise itself upon its wings, it is enabled to
rise in the air, and sustain a long and power-
ful flight with but little muscular exertion.
In the pupa and larva state respiration is per-
formed more equally by all the spiracles, and
less especially by the thoracic ones.

The frequency of the acts of respiration
seem to bear some relation to the expenditure
of muscular energy by the insect in a state of
activity. All volant insects respire a greater
quantity of air in a given time than terrestrial,
and both these in their perfect than in their
larva state. Thus in the common hive-bee we
have noticed from one hundred and ten to one
hundred and sixty contractions of the abdo-
minal segments in a minute, while in a less
active state, when the insect was entirely un-
disturbed, the acts of respiration seldom
amounted to one-half that number. In an
exceedingly wild and irritable little bee, An-
thophora retusa, which dies exhausted from the
most violent excitement and exertion, in the
course of an hour or two, after being captured
and confined during summer, the acts of re-
spiration are often performed so rapidly that, on
one occasion on which we observed them, they
amounted to two hundred and forty in a minute,
and of course it was only by the closest atten-
tion that their number could be ascertained.

Next to the pupa state, a state of common
repose is that in which insects respire with the
least frequency. When a perfect insect or a

pupa has remained for some time undisturbed,
its respiration becomes gradually slower and
slower, until at last it is scarcely perceptible.
Thus, in the midst of winter, at a temperature
of the atmosphere a little below freezing, we
were unable to detect more than the very
slightest trace of respiration during two or three
days, and even at the expiration of fourteen
days the quantity of carbonic acid gas formed
was very small. But when the insect was re-
moved into a much warmer atmosphere it
began again to respire more freely, and the
quantity of carbonic acid produced in a given
time was considerably increased. In a speci-
men of Bombus terrestris, which had remained
at rest for about half an hour, the respirations
had become deep and laboured, and were
continued regularly at about fifty-eight per
minute. At the expiration of one hundred
and forty minutes, during which time the in-
sect remained in a state of repose, the respi-
rations were only forty-six per minute, and at
the expiration of one hundred and eighty mi-
nutes they were no longer perceptible. This
same insect, when first captured, and in a state
of moderate excitement, respired at the rate of
one hundred and twenty-five inspirations per mi-
nute. We have noticed the like circumstances in
a female Sphinx ligustri, which after it had been
excited for a short time in flight breathed at the
rate of forty-two respirations per minute, while
after it had remained at rest about seventy-five
minutes respired at the rate of only fifteen per
minute. Hence the quantity of air deterio-
rated by an insect in a given time depends
upon the state of activity and condition of life
of the individual. In accordance with the
frequency, and consequently the quantity of
respiration, such are the results. In accele-
rated respiration the circulation of the fluids
is increased, and in those conditions, noticed
in another part of this paper, in which the cir-
culation is accelerated, the acts of respiration
are at the same time more frequent.

The development of heat, which is now found
to take place in all insects as in the air-breath-
ing vertebrata, depends mainly upon the quan-
tity and activity of respiration, and the volume
and velocity of the circulation. In Hymenop-
tera, in which, as we have seen, the capacity of
the respiratory organs is greater than in other
insects, and consequently the quantity of air
deteriorated in a given time is also greater, the
quantity of heat evolved during the process is
proportionate to the quantity of respiration. In
the larva, in which, in relation to its size, the
quantity and energy of respiration are less than
in the perfect insect, the quantity of heat deve-
loped is also less, so that in the larvae of Hyme-
noptera it does not exceed from two to four
degrees that of the medium in which the insect
is placed ; while in the perfect insect, in a state
of little activity, the quantity of heat developed
is apparently at its minimum amount at three
or four degrees above the temperature of the
surrounding medium. But when the same
insect is in a state of moderate activity, and
consequently is respiring more frequently, it

INSECTA.

989

amounts to even fifteen or twenty degrees. In
all cases the amount of temperature depends
chiefly upon the quantity of respiration.

We have seen that in a state of repose the
acts of respiration become less and less frequent,
and that at last they are scarcely perceptible.
In like manner the amount of heat generated
is proportionate to the diminished number of
respirations, and continues to be lessened until
the temperature of the insect has very nearly
sunk down to a level with that of the atmo-
sphere. There are also other circumstances
which moderate the production of heat. When
the insect is fasting less heat is generated, even
during a state of activity, than when the insect
is not deprived of its proper quantity of food.
The cause of this deficiency seems readily to be
accounted for on the consideration that no new
material, the product of digestion, is taken into
the general circulation, and requires to be assi-
milated with the circulatory fluids, and, conse-
quently, there is less change in the chemical
condition of the fluids at each respiration, than
when the animal is taking its full amount of
food. Other circumstances also tend to regu-
late the amount of heat. When the insect is
respiring rapidly, the power and frequency of
its circulation are augmented, and not only is
there a greater quantity of gaseous expenditure
from the respiratory organs, but there is also a
greater amount of cutaneous expenditure, which
tends to cool down the insect by evaporation
from the surface of its body, and diminish the
amount of heat developed. This expenditure
is so enormous, as we have elsewhere shown,*
that it is more than equal to the quantity of
solid matter excreted from the alimentary canal
in a given time, and, consequently, is a power-
ful means of reducing the temperature of the
insect. One very marked difference which ex-
ists, in respect to the function of respiration and
the evolution of heat, between these air-breath-
ing invertebrate and the vertebrated animals
is, not in their different powers of generating,
but of maintaining their temperature. Insects
in their low power of maintaining heat closely
resemble the true hybernating animals. Any
great or sudden change of temperature in the
surrounding medium rapidly reduces the tem-
perature of the insect. It is thus seen that a
reduction of temperature takes place not only
at the period of true hybernation, which insects
undergo either in their pupa or perfect state,
but also during vicissitudes of the season, as
well as during natural repose. On the other
hand, it is remarkable that the evolution of heat
in insects takes place as rapidly as it becomes
reduced. Its increase is perceptible by the
thermometer within a very few moments after
the insect has begun to respire more rapidly.
The explanation of this circumstance must be
sought for in the peculiar distribution of the
respiratory organs, which are extended over the
whole body, and aerate the blood in every part
of it at the same instant, the result of which is
the immediate evolution of a large amount of
heat, from the changes that occur in the fluids

* Phil. Trans. 1837, p. 2.

in vessels that partake both of the venous
and arterial character. Consequently a large
amount of heat is liberated instantaneously,
whether the oxygen of the atmosphere be ab-
sorbed into the circulatory system, or whether
the whole of the changes take place, and car-
bonic acid be formed in the respiratory struc-
tures. The same rapidity with which the heat
is evolved from the body accompanies its dimi-
nution when the quantity of air inspired is
lessened. In confirmation of this view with
regard to the production of heat being the result
of the chemical changes in the air inspired,
there is one remarkable circumstance that can-
not be passed over. It is the voluntary power
which we have found is possessed by some
species of generating heat by means of accelera-
ting their respiration. Wre observed this fact in
the individuals of a nest of Humble-bees, 'Bom-
bus terrestris, which were confined by us for
the purpose of watching their habits. Huber
formerly noticed that bees are in the habit of
incubating on the cells of their pupse, before the
perfect insects are developed, and we have had
ample opportunities of confirming his observa-
tions. It was during the time that we were
engaged in watching these habits that we dis-
covered that bees possess this voluntary power
of increasing their temperature. The manner
in which the bee performs her incubatory office
is by placing herself upon the cell of a nymph
that is soon to be developed, and then begin-
ning to respire at first very gradually. In a
short time the respirations become more and
more frequent, until at length they are increased
to one hundred and twenty or one hundred
and thirty per minute. The body of the insect
soon becomes of a high temperature, and on
close inspection is often found to be bathed
with perspiration. When this is the case the
temperature of the insect soon becomes re-
duced, and the insect leaves the cell, and ano-
ther bee almost immediately takes her place.
When respiration is performed less violently,
and consequently less heat is evolved, the same
bee will often continue on a cell for many hours
in succession. During these observations we
have, in some instances, found the temperature
of a single bee exceed that of the atmosphere
more than twenty degrees. Thus when the
temperature of the atmosphere was 73° 5 Fahr.
that of four female bees, in the act of incuba-
tion, was 94° 1. On another occasion when
the atmosphere was 72° 5, a single bee,
nursing on a single cell, from which a per-
fect insect was developed about eight hours
afterwards, afforded a temperature of 92° 3,
the bulb of the thermometer being placed
between the abdomen of the bee and the
cell. The insect was then breathing at the
rate of one hundred and twenty respirations per
minute. In another instance, the temperature
of the atmosphere being the same, that of ano-
ther bee in the act of nursing was 94° 5.
This extreme amount of heat was evolved en-
tirely by an act of the will in accelerating the
respiratory efforts, a strong indication of the re-
lation which subsists between the function of
respiration and the development of animal

990

INSECTA.

heat. These curious facts tend much to con-
firm the opinion as to the chief origin of animal
heat, but for farther illustration of this interest-
ing subject we must refer our readers to the
article RESPIRATION.

Organs of generation. — These parts have
already been treated of to some extent in a
preceding article, (GENERATION, ORGANS OF,)
and the forms which they assume in different
orders, more particularly those of the male
organs, having in part been described, we
shall only briefly allude to them on the present
occasion, in consequence partly of the great
length to which this paper has already been ex-
tended, and partly that we shall necessarily
return to this subject, more especially with re-
ference to the functions of these parts, in de-
scribing that class of Articulata, which in every
respect are so closely related to insects, the
Myriapoda, to which we must refer.

In our observations on the skeleton we have
shown that the terminal segments of the body
invariably form part of the external organs of
generation. The long ovipositor of the Chry-
sididte, composed of four distinct annuli, retrac-
tile within one another, and even within the
proper abdomen itself, are only the terminal
segments of the body, which is thus made to
consist of fewer, but proportionately larger
annuli than the abdomen of those in which so
many segments are not employed in the forma-
tion of the generative organs. A corresponding
structure is also seen in the Panorpidx, in
which the separate annuli, not retractile to so
great an extent as in the Chrysidida, but capa-
ble of being extended to as great a length, are
distinctly shown to form part of the abdomen,
while the corresponding parts in the male, the
terminal segments, are developed into a claw-
shaped prehensile organ. A similar modifica-
tion of structure exists in all other insects. In
some species one or more of these parts be-
comes atrophied, or is developed to a greater
extent than the others, and the result is that in
some instances we find long, exsertile, and appa-
rently new organs, while in others some parts,
even of the annuli themselves, appear to be ab-
sent. But the normal number is almost every
where present, either simply as terminal plates
of the abdomen, between which the proper ex-
cretory portion of the organs of generation is
concealed, or more highly developed, and form-
ing a separate sheath for that structure.

In the male insect (fig. 437) the organs con-
sist of an external portion, the penis (h), or
*' organ of intromission," in which is inclosed
the termination of the ductus ejaculatorius,
which extends backwards, and is connected
with the vesiculte seminules (e} and vasa defe-
rentia, which are connected with the epididymis
and the proper testes (a). These parts are
found in a large number of insects, in some de-
veloped to a great extent, but in others almost
entirely atrophied. This is the order in which
the parts are met with when passing from
without inwards.

The penis of the male, like the ovipositor of the
female, assumes a variety of forms. It is usu-
ally inclosed between two lateral plates, the ana-

Male organs' of generation
*of Athalia centifolice.
. (^ize Essay.) ±

Fig. 437. Jogues of the sheath

of the ovipositor, and
which are derived
from the terminal or
penultimate segment
of the body. With-
in this is a corrugated
soft membrane, the
preputium, which is
continuous with, and
is reflected inwards
from the inferior
margin of the anal
aperture, and sepa-
rates the organs of
generation from the
alimentary canal.
When the penis is
retracted it is covered
by this membrane,
which is corrugated
upon it (fig. 402, s).
In Coleoptera, as in
the Carabidte and
Melolonthida, the
penis is a long hor-
ny tube, retractile
within the abdomen on the under surface as far
as the anterior segments. The strong horny co-
vering of this organ is simply a consolidated state
of parts of the tissues which in other instances
are soft and flexible. It contains within it the
excretory portion of the ejaculatory duct. In
most of the Coleoptera, and in many other
Species, it has this strong hardened exterior, ne-
cessary apparently for its employment by cer-
tain species, in which there is little flexibility
of the abdominal segments, as an organ of in-
tromission. In Carabus monilis, as noticed
also in C. clathratus by Burmeister, the hard-
ened case of the penis is gently curved down-
wards to facilitate its introduction into the vulva
of the female. At its extremity on the under
surface it is a little elongated, and it is termi-
nated by a soft corrugated glandiform structure,
which is perforated in its centre, and represents
a glans penis, the perforation in its centre being
the orifice of the excretory duct. In other
Coleoptera the penis is also inclosed in a horny
sheath, and presents a great variety of forms in
different species. In many instances it is fur-
nished at its extremity with short hooked spines,
by means of which the male effectually retains
his connexion with the female. The external
sheath of the male organs, which incloses the
penis, is analogous to that of the ovipositor of
the female, and is employed when it is well
developed to open the vulva of the female. In
many species it is scarcely at all developed,
being like the sheath of the ovipositor only a
highly developed portion of the lateral plates of
the terminal abdominal segments. The cir-
cumstances above referred to will not allow us
to describe in detail the forms of these organs
of generation in many species, we shall there-
fore content ourselves with a brief notice of
some of those of the Hymenoptera (Jig. 437).
The general form of the penis in this Order is
similar to that of Athalia, and consists of a

INSECTA.

991

short valvular projectile organ, covered exter-
nally by two pointed horny plates (i), clothed
with soft hairs. Above these are two other
irregular double-jointed plates (/), convex on
their outer and concave on their inner surface,
and surrounded at their base by a bony ring
(A-). They are half corneous half membranous,
and folded together like a closed fan, and are
furnished at their posterior margin with horny
hooks (i), which are used as organs of prehen-
sion. Between these in the middle line are
two elongated muscular parts (w), which when
applied together form a pointed structure, and
inclose between them in its retracted state the
proper intromittent organ (A). These perhaps
assist to dilate the vulva of the female, like the
plates above noticed in the Coleoptera. In
many instances, as in Anthidium momentum,
the posterior margin of the last true abdominal
segment is armed with spines that are curved
downwards, and serve to retain the female, and
this is also the case in the Ckryudidsf. In
Anthophora return the horny penis formed of
the last two segments of the larva has also two
external plates developed into hooked prehen-
sile organs, with which the insect grasps the
abdomen of the female at the moment of actual
connexion. In the Sphinx f^g.391) and other
Lepidoptera the appendages of the anal seg-
ment appear to be analogous to the sheath of
the ovipositor in the preceding orders. On
each side of these parts at their inner surface
are two horny plates, which form the lateral
boundary of the male organs. Within these is
a cloaca, in which the anal aperture terminates,
and immediately beneath it are situated the
male organs. These consist of an extensile
bind, ejaculatory organ included between two
soft valvular parts. They form the virile
organ. In the Sphinx the posterior margin of
the dorsal plate of the terminal segment is
armed with a slender curved hook, bifid at its
apex, and bent downwards, like the hooks in
the body of Hymerioptera, for retaining con-
nexion with the female. Among the Diptera
the Asilida: have the male organ formed in a
somewhat similar manner. The terminal seg-
ment of the body forms a pair of broad horny
plates, which inclose between them the double
stiliform excretory canal.

The duclitfi cjaculatorius passes backwards
from the penis as a single canal, which either is
exceedingly short, as in Athalia, (fig. 437,/J,
or is a very long tube, forming many convolutions
in its course, as in many of the Coleoptera.
Into this canal open the vesicnla aernijiales and
the vasa deftrentiu. The vesicula seminales are
usually long convoluted ccecal tubes, which
assume a variety of forms, sometimes branched
sometimes simple. They are two, and some-
times four in number. In some species, as in
Athalia (e}, they are exceedingly short, and
very much dilated, serving evidently as recep-
tacles for the semen as it is secreted by the
testes, and conveyed towards the ejaculatory
duct by the vasa deferentia (d). These, like
the seminal vessels, vary in number according
to the number of the testes. When the whole
of the testes are aggregated together, the vasa

deferentia that proceed from them are united
from each set of testes into a single tube on
each side (6), but when the testes remain dis-
tinct from each other, each deferential vessel
passes at first separately from each testis for a
short distance, and the whole are then collected
together, and form on each side a single tube,
which, after many convolutions, either is in-
serted into the extremity of the seminal vessel,
or is inserted along with it into the commence-
ment of the ejaculatory duct. The length of
the common deferential vessels is sometimes so
great, and they are so much convoluted, as to
be readily mistaken for testes, much larger than
the proper testicles. This is the case in Athalia
(d}. The proper testes are usually several
rounded glandular bodies, in some instances, as
in Melulontha* and Lucanus, amounting to as
many as six on each side, and in a few in-
stances, as in Athalia, even to as many as thir-
teen. In form they are sometimes rounded, and
sometimes are elongated cceciform tubes. They
are usually regarded as ccecal organs, but in
some instances we have distinctly traced minute
vessels connected with them, but whether these
vessels passed by open mouths directly into the
coeca, or whether distributed over their surface,
is perhaps still a question ; our impression cer-
tainly is that they enter the testes. Besides
these parts, there are in some instances struc-
tures that resemble an epididymis, as in Hy-
dromfi but these are generally absent.

These organs lie within the abdominal cavity,
in general on each side of the alimentary canal,
and sometimes above it, as in the instance of
the Lepidoptera, in which the two separate
testes of the larva (fig- 364, i) are united in
the perfect insect into one mass, which is situ-
ated immediately beneath the dorsal vessel
(Jig- 366, *'). In each of these cases the con-
nexion with the vessel, as formerly noticed, is
distinctly traced. Besides these parts we ought
also to notice some which are appendages of
the organs similar to appendages found in the
female, but the function of which is not dis-
tinctly understood.

In the female the organs of generation are
more simple than in the male. Of these we
have first to notice those external parts which
form, as we have stated, either the long ex-
tended ovipositor of the GrryUufa, the sheath
of the sting of the bee (fig. 438, A, a,d), or
the sheath or valves of the ovipositor of the
Terebrantia (C, b}. The condensed descrip-
tion of these parts that has been given by Mr.
WestwoodJ clearly explains their structure.
He remarks that, " from the centre of the
under side of the abdomen, near its extre-
mity, arise two plates, each consisting of
two joints, sometimes valvular and together
forming a scabbard, sometimes more slender,
and resembling palpi, and sometimes very
long ; between these plates, as they exist in the
bee (A, 6), under the form of two flattened
plates, with a pair of terminal lobes, arise two
other pieces which are very slender, serrated

* Straus,
t Dufour.
t Entomologist's Text Book, p. 375.

992

INSECTA.

A, lateral view of the sting of the Bee. (Westwood.)
a, the sheath ; 6, terminal segment of the abdo-
men ; c, the barbs or proper sting ; d, the chan-
neled surface of the sheath of the sting in which
the barbs are concealed.

B, the poison-bag and vessels of the sting of the
Anthophora return ^Newport) ; a, sheath of the
sting ; b, the dilated extremity of the poison duct ;
c, d, the bag ; e, efferential vessel ; /, the secretory
organs; g, their vessels.

C, terminal segment of the abdomen of a saw-fly,
Trichosoma (Lyonet) ; a, dorsal end of the ter-
minal segment ; b, sheath of ovipositor or terminal
ventral arch ; c, d, the inner plates or saws, analo-
gous to the barbs, c, of the sting of the bee.

D, one of the double lancet-pointed saws of
Athalia centifolice.

at the tip in the bees (c) but much broader in
the saw-flies (C, c, d) and transversely striated,
forming the saws with which these insects are
provided: moreover these two pieces are re-
ceived in the bees into a canal (A, </), but in
the saw-flies this gutter is broad, flattened, and
divided into two separated parts, forming the
backs of the two saws. In the Ichneumons
these various parts are so slender that at the
first sight they appear to consist but of a single
piece : on more minutely examining the in-
strument, however, it will be found that it
consists of a scabbard, composed of two pieces,
inclosing a fine hair-like bristle, which is, in
fact, the exact analogue of the stinging part of
the bee's sting, consisting of three pieces."
This organ constitutes both a means of defence
and also of depositing the eggs. There have been
some doubts with regard to this fact in the
bees, some having questioned whether the sting
is at all employed in oviposition by these in-
sects ; but a most careful and accurate ob-
server, Dr. Bevan, distinctly states that the
ova pass along the sting of the bee to be de-
posited, and this statement is confirmed by
the fact that this is certainly the case in the

analogous instrument of the saw-flies, as we our-
selves have distinctly witnessed in Athalia
centifolite. The analogy, therefore, of the sting
with the ovipositor of the Gryllida, of the saw-
flies, and other insects, is distinctly proved. In
Athalia the ovipositor is a very interesting
organ. It occupies the under surface of the
seventh and eighth segment of the body, and
is approximated to the posterior margin of the
sixth, a part of the seventh having been re-
moved. Four tendons for the insertion of
muscles originate from the extremity of the
two halves of the ovipositor. In the mem-
brane that unites on the under surface the two
halves of the ovipositor, is situated the vaginal
orifice between the two saw-shaped organs
(C, c, d, D). Each of these parts is composed
of two plates applied together back to back,
and which together form a pointed instrument
resembling a lancet (D). The upper one of
these plates (i) is furnished with small sharp-
pointed teeth directed backwards, and the
under one (&) with fourteen long and slightly
convex ones. With the point of this instru-
ment the insect pierces the edges of the leaves
of the turnip, separating the cuticle with its
saw preparatory to depositing its egg, which is
conveyed along its inner surface, which is
slightly concave to allow of its safe transit
along the plates. Posteriorly and external to
these plates are the two sheaths of the ovipo-
sitor (C, b) analogous to one portion of the
ovipositor of the Gryllida. In all those Hy-
menoptera furnished with an ovipositor there is
also an apparatus for secreting a peculiar fluid,
and this apparatus is believed to be analogous
to the appendages of the male organs above
alluded to, the use of which is not well under-
stood. In the female these parts consist of an
excretory duct, and bag, or receptacle for the
fluid, a convoluted efferential vessel, and proper
secretory organs. In the wild bee, Anthophora
retusa (B), at the base of the sheath (a) in
which the two barbs of the sting (A, e} are
concealed, is a smooth dilated space, into which
the poison is first received at the base of the
sting. The poison is conveyed to this space
by the efferential duct (c) from an oval sac (d);
in which it is accumulated as secreted, and into
which it is poured by a very large and much
convoluted efferential vessel (e\ which receives
the fluid from two cceciform glandular organs
C/'J, which unite as they enter the efferential
vessel. These secretory organs receive at their
apparently closed extremity each a minute
vessel, which we have distinctly traced to some
distance from them, but not to its termination.
When the poison is ejected from the bag (d)
into the base of the sting, it passes along be-
tween the two barbs, as in a little gutter, into
the wound. Swammerdam delineated these
parts in the honey-bee, but did not notice the
vessels proceeding from the secretory organs.
In another insect of the same class there are
similar structures. Thus, in Athalia (JigA39\
the bag (g) is oval, but the efferential vessel is
entirely absent, the fluid being poured directly
from the secretory vessels (A) into the bag with-
out passing along any other tube. The vessel is

INSECTA.

993

Fig. 439.

Female organs of generation of Athalia centifoliqe.
(Prize Essay.)

also absent between the bag and the base of the
ovipositor, so that the fluid is forced directly
from the bag at the moment it is employed.
There is a somewhat similar structure in the
Hornet, although the vessel between the bag
and sting is present as in the bee. Burmeister
has suggested that the poison-gland may per-
haps be an urinary organ, but the circum-
stance of the fluid contained in it being em-
ployed by the insect to inject into the cavity
in which it deposits its ova, seems opposed to
this opinion, although that of its being em-
ployed by the bee as a means of defence may
be favourable to it. The nature of this fluid
is distinctly acid, as remarked by Dr. Bevan
in the honey-bee, and as found by ourselves in
several instances. The vaginal aperture at the
base of the ovipositor forms the external orifice
.of the common oviduct or proper laying tube
(e). This in some instances is simply a di-
lated orifice, the internal lining of which is
.continuous with that of .the internal part of the
ovipositor. This common oviduct is either a
simple, straight, uniform tube, or in some in-
stances is a little dilated laterally into pouches,
in which are received the lateral appendages of
the male organ, as in Melolontha. At its
termination the common oviduct divides into
or rather receives two separate tubes (d),
one from each side, analogous to the efferential
vessels of the male organs. On the upper
surface of the common oviduct, there are
appendages that vary in number from one to
five. The chief of these, the spermatheca (f),
alone exists in Athalia. It is into this sac that
the fluid of the male is ejected during co-
pulation. Audouin states that the male organ
is projected into it. We have invariably found
this vesicle, which is exceedingly large in Mcloc,
filled with white, opaque, seminal fluid after
connexion with the male, previously to which
time we have as invariably found this vesicle
-empty. This appendage is simple in many of

"'OL II.

the Orthoptera as well as in Hymenoptera, but
in some other species there are also additional
vesicular appendages which have been de-
scribed as secreting a glutinous fluid. In all in-
stances these are attached to and pour their con-
tents into the common oviduct, through which
the eggs pass to be deposited. In the middle
line, at the union of the oviducts, are situated
the terminal ganglia of the nervous cord
(10, 11), when the cord is extended to the
posterior part of the abdomen. But when this
is not the ease, and the nerves simply radiate
from the thorax into the abdomen, the terminal
pair of nerves still pass in a corresponding
direction over the union of the oviducts, thus
always occupying a position between the organs
of generation and the termination of the ali-
mentary canal. From the two oviducts origi-
nate the proper ovarial tubes. In Athalia cen-
tifoli(E there are eighteen (a, b, c) attached to
each oviduct, but in some other instances, as
in Meloe, in which the upper part of the
oviduct on each side is dilated into an im-
mense bag resembling an uterus, they amount
to some hundreds of exceedingly short tubes
containing each but one or two ova. In Melo-
lontha and Lucanus there are six on each side,
but in some instances, as in Lixus, as shewn
by Dufour,* there are only two on each side.
These ovarial tubes gradually decrease in si?e
from their base to their apex, and those from
each side are collected together at their apices,
and are said to terminate each in a dilated
coacal extremity, but we must confess we have
never yet traced this structure in any instance.
Miiller, as above stated, traced a connexion
between the extremities and the ovarial tubes
and the dorsal vessel in Phasma, and many
other insects, as we have also done in several
instances, but the nature of these connexions
is disputed. They certainly appeared to us
to be vascular, as supposed by Miiller, and
we have already stated the reasons that led us
to the same opinion.

We shall enter on a consideration of the
function of the organs of generation when con-
sidering this subject in MYRIAPODA.

In concluding this lengthened article we
have only further to remark that the tegumen-
tary appendages consist of hair, scales, and
spines. The first of these serves as a covering
for the bodies of many species, more particu-
larly the Hymenoptera, and is also foun4
under the limbs in many Coleoptera. The
scales are peculiar appendages and may be
considered, according to many, as simply flat-
tened hairs. They entirely cover the bodies of
many species, as for instance the Lepidoptera.
The curious forms and marking of these parts
are sometimes exceedingly beautiful ; but the
limits of our article will not allow of our en-
tering at present on the consideration of them.
The spines are found much on the wing .of Hy-
menoptera and are often mistaken for true hairs,
between which and spines, and also between
these and scales, there is a difference of origin,

* Annales des Sciences Naturelles, torn. vi.
pi. 20.

3 T

994

INSECTIVORA.

spines being usually developed directly from a
trachea or part of a membrane in the immediate
vicinity of a trachea.

BIBLIOGRAPHY.— In addition to the foot-notes
attached to the article the following are some of the
principal works on Insects : De Animalibus Insectis
libri septem, A uctore Ulysse Aldrovandce, fol. Bonon.
1602. Experimenta circa Generationem Insecto-
rum, Francisco Redi, Florence, 1668. De Bombyce,
JJ/. Malpighi, 1687 ? Historia Insectorum, Londini,
1710. Methodus Insectorum, seu Insecta in Metho-
dum aliqualem digesta, Johannes Ray. Systema
Naturae, 1735-1770, Carolus von Linnaeus. Memoires
pour servir a 1 'Histoire des Insectes, par Charles De
Geer, 7 torn. 4to. Siockholme, 1752. Traite d'ln-
sectologie, par Charles Bonnet, 8vo. Paris, 1748.
Biblia Naturae, fol. by J. Swammerdam, translated
by Thomas Flloyd, with Notes by J. Hill, London,
1758. Entomologia Carniolica, exhibens Insecta
Carnioliae indigene, &c. 8vo. Joannis Antonii Scopoli.
Vindobonas, 1763. Memoires pour servir a T Histoire
des Insectes, 6 torn. 4to. par Rene Antoine Erchhault
de Reaumur. Traite Anatom. de la Chenille, 4to.
par Pierre Lyonet, 1760. Spicilegia Zoologica, &c.
a Petr. Sim. Pallas, M.D. 4to. Berlin, 1767-1780.
Systema Entomologiae, &c. 8vo. Jo. Christ. Fabricii,
Flensburgi et Lipsiae, 1775. Novae species Insec-
torum Centuriae 1. Auctore Joanne Rionoldo Fostero,
6vo. Londini, 1771. Historia Nattiralis Curculio-
num Sueciae, Auctore Gabriel Bonsdorf, 4to. Up-
ealiae, 1785. Entomologia Parisiensis, edente A . F.
Fourcroy, M.D. 2 torn. 12mo. Parisiis, 1785. Ex-
position of English Insects, arranged according to
the Linnean System, 4to. London, by John Harris,
1782. Entomologia Helvetique ou Catalogue des
Insectes de la Suisse, ranges d'apres une nouvelle
Methode, avec Descriptions et Figures, Claiville,
Zurich, 1798. Tableau elementaire de THistoire
Naturelle des Animaux, par G. Cuvier, 1797.
Natural History of British Insects, by E. Donovan ,
16 vol. 8vo. London. 1792-1818. De antennis In-
sectorum, 8vo. 1799, Lehmann. Vivarium Nature,
the Naturalist Miscellany, by G. Shaw. Lepidop-
tera Britanniae, Auctore A. H. Haworth, 8vo. Lon-
dini, 1803. Monographia apum Anglise, by W.
Kirby, M.A. 2 vol. 8vo. Ipswich, 1802. Introduc-
tion to Entomology, by William Kirby, M.A. and
William Spence, vol. iv. 1816-1828. Historia Nat.
des Animaux sans Vertebres, &c. par M. le Cheva-
lier de Lamarck, 5 torn. 8vo. Paris. Extrait du
Cours de Zoologie, &c. par M. de Lamarck, 1812,
8vo. Elements of Natural History, 2 vol. 8vo.
London and Edinburgh, 1802, by Stewart. Histoire
Naturelle des Crustaces et des Insectes, par P. A.
Latreille. British Entomology, by John Curtis,
F.L.S. Histoire abregee des Insectes, Paris,
1764, 2 torn. 4to. by Geoffroy. Illustrations of
British Entomology, by James Francis Stephens,
F.L.S. Horae Entomologia?, by W. J. Macleay.
Entomologia Britannica, 1 vol. 8vo. 1802, by Tho-
mas Marsham. Considerations Generates sur I'Ana-
tomie comparee des Animaux Articules.par Hercules
Straus Durckheim, 4to. Paris, 1828. Modern Clas-
sification of Insects, by J. O. Westwood, F.L.S.
(G. Newport.)

INSECTIVORA, (Insecta, voro,} a group of
mammiferous animals, considered by some au-
thors as a distinct order ; by others, and parti-
cularly by Cuvier, as a family only of the great
carnivorous order, named by that great natura-
list CARNASSIERS. The peculiarities of struc-
ture by which the Insectivora are characterized
appear to me to be equally important with those
which have led me already to treat of the Chei-
roptera as an ordinal group, and I shall there-
fore consider them in that point of view.

They consist of four very distinct groups,

the relations of which are not very clearly
fixed. I have ventured to consider them as
four families, viz. : —
TALPID^E, typified by the mole, Talpa.
ERINACEADA:, by the hedgehog, Erinaccus.
SoiiiciD-E, by the Shrews, Sorex.

TUPAIAD^E, by the genus Tupaia.

Such at least appears to me, in the present
state of our knowledge, to be a near approach
to the natural groups of which the order is
composed. In the Talpida I include the ge-
nera Talpa, Condytura, and Chrysochloris ; in
the Soricida, the genera Sorex, (with the sub-
genera, so called, into which it has lately been
subdivided,) Mygale and Scalops, the latter
genus being clearly osculant between the
Soricida and the Talpida ; in the Erinaceada,
the genera Erinaceus, Echinops, and Centenes ;
and in the Tupaiada, the single genus Tupaia,
or Cladobates, as it is named by Fred. Cuvier.

It will at once be seen, by reference to this
enumeration of the types of form which occur
in this order, that animals, differing greatly in
their general structure and habits, are included
in it. But it will also be found that they all
agree in the general character of their teeth,
which are in all instances furnished with ele-
vated and pointed tubercles, for the purpose of
breaking down the hard and polished elytra of
coleopterous insects, upon which most of them
in a greater or less degree subsist. This cha-
racter has already been exhibited in the insecti-
vorous group of the Cheiroptera, which we have
considered as leading towards the present order ;
and even in the lower forms of the Quadru-
mana a similar tendency is evident, as in the
Maki, the Loris, and others. They agree, also,
in being for the most part nocturnal animals,
and, with some exceptions, in living under
ground, or at least in exhibiting a tendency to
such a mode of life; and all those which in-
habit the colder countries pass the winter in a
state of torpidity. They all possess clavicles ;
their limbs are generally short, and they are
plantigrade. They have ventral mammae, the
stomach is perfectly simple, and they are desti-
tute of a coecum.

The different families which I have named
are as well characterized by their habits as by
their external form, and their more intimate
structure. The Talpida, the teeth of which are
shewn in the genus Talpa (fig- 441,) and Chry-
sochloris (fig. 450), which are pre-eminently
subterranean, are distinguished by their extra-
ordinary habits of forming long and complicated
burrows underground, passing their whole lives
in a subterranean retreat, in which they are born,
feed, breed, hibernate, and die ; and which re-
treat, in the case of the common mole, is formed
with the utmost art, and a beautifully complica-
ted construction. The Soricida (Jig- 449) are
a sort of carnivorous mice; and although they do
not actually burrow, retreat during the winter,
and in their ordinary repose, into holes, feed-
ing, however, on the surface or in the water,
several of them being partially aquatic, diving
with facility after aquatic insects, and remain-
ing without difficulty a long time under water.
In both these families there is a peculiar cha-

INSECTIVORA.

995

racter in the structure of the hair, which favours
the habits I have mentioned, and which will
be presently described. In the Erinaceada (see
Jig. 451) we still have hibernating animals, but
these, instead of burrowing or descending into
deep excavations, conceal themselves only under
leaves, or in any superficial hollow, and live
upon food which they either find upon the sur-
face or dig out of the ground with their hard
moveable muzzle ; the character of their integu-
ment is very peculiar, the hair being modified
into spines of a greater or less degree of firmness,
and the animals being mostly capable of rolling
themselves into a ball, and thus presenting a
panoply of sharp spines to their enemies. The
last-named group, which I have named Tupai-
ad&i (jig. 452) partake, as before observed,
of the character of the Insectivorous Quadru-
mana; living in trees, which they climb with
all the agility of a monkey or a squirrel. They
Consist but of a single genus, named by the late
Sir Stamford Raffles, Tupaia, of which three
species are well distinguished. They are na-
tives of Java.

I. Osteology. — It can scarcely be said that
there is any peculiarity of structure in the ske-
letons of the whole of the insectivora, in which
they differ essentially from other groups ; but
on the other hand, there are many in which
they differ from each other, according to the
very striking and obvious diversity of their ha-
bits. In the family Talpida, the genus Talpa
(Jig. 440) presents itself as the type. In these
animals the cranium is greatly elongated, and
of a tapering or conical form, a character
which it partakes with the Soricidte, but to
a still more remarkable degree. The cra-
nium of the Chrysochloris, or Cape-mole, the
South African representative of this family,
presents this character in the most regular
form. It is, in fact, a perfect cone, short, pointed
at the muzzle, broad behind, where the base of
the cone is distinctly circumscribed by a crest,
which passes from the root of the zygomatic
arch of one side, over the vertex, to the cor-
responding point on the other ; on the sides of
the head the zygomatic arches themselves com-
plete the cone, passing obliquely and in a
straight line from the maxillary to the temporal
bone, and beneath it is completed by the in-
clination inwards of the symphysis, the
rami, and the coracoid processes of the lower
jaw. The portion posterior to the base of the
cone is rounded.

In the genera Talpa ( 'Jig .441) and Condt/tura
the head is equally but less regularly conical,
and the snout is more elongated; the zygomatic

Fig. 441.

arch is extremely slender, and rises obliquely,
joining the cranium considerably above the audi-
tory meatus. A similar conformation is seen in the
genus Scalops, which I have already mentioned
as leading from the Talpida to the Soricidte.
This form is admirably suited for their subter-
ranean progression, as they push their way
through the soil by their long moveable snout,
which acts in some measure as a wedge.
Amongst the Soricidte, the Scalops approaches
in its structure most nearly to the Talpida,
having the almost perfectly conical form of the
head which belongs to that family ; and all the
Soricida partake of it to a greater or less degree.
But the cranium of the Erinaceada approaches
more nearly to that of the Carnivora; and
viewed from above, the sides are nearly parallel,
the zygomatic arches projecting further than the
posterior part of the cranium. The muzzle
is shorter, more obtuse, and somewhat
narrower than the cranium, which is com-
pressed forwards. In Centenes the head is
much more elongated and conical. The genus
Tupaia has the head nearly oval, the muzzle
straight, prominent, much smaller than the cra-
nium, the zygomatic arches but slightly pro-
minent, and the circle of the orbit closed pos-
teriorly, a circumstance which is not found in
any other of the order Insectivora. In this

Fig. 440.

3x2

996

INSECTIVORA.

genus the orbit is therefore circumscribed by
being closed posteriorly by the union of the
post-orbitar processes of the frontal and jugal
bones ; in all the other genera the orbit and the
temporal fossa are confounded in one cavity,
without the trace of any attempt at forming a
division between them. This peculiarity in the
genus Tupaia shews a marked tendency to-
wards the insectivorous Quadrumana.

The bones of the face are very early united
in the Talpida and the Sorieida. In the
genus Centenes there is no jugal bone. There
is therefore no zygomatic arch, notwithstanding
the masseter muscle is of great size. This is
attached by a single tendon to a sort of tu-
bercle, which represents the zygomatic process
of the maxillary bone. In Tupaia the inter-
maxillary bones are very large, and their
suture descends vertically, nearly half way be-
tween the nares and the orbits. The Shrews,
like Centenes, have no malar bone, and the
zygomatic process of the maxillary is even less
conspicuous than in the former genus. Most
of the subterranean forms have at the extremity
of the muzzle, that is to say, around the open-
ing of the nares, a small rim or border, which
is especially conspicuous in the Chrygpchloris,
for the attachment of the large and moveable
cartilages of the nose, so important to these
animals in turning aside the earth as they make
their way through the ground, as well as in
seizing the worms and insects on which they
feed.

The proportions of the spine vary greatly in
the different families of Insectivora, as may be
anticipated from the great difference in their
habits. On this subject it may not be useless
to subjoin the following table of the numbers
of the separate classes of vertebrae, which is
taken from the last edition of the Lecons d'Ana-
tomie Comparee of Cuvier : —

1

Lumbar.

Sacral.

Coccygeal.l

if!

12

Erinaceus Europceus (Hedge-
hog)

1 f>

6

3

1°

43

Centenes ecaudatus (Tenrec) .
C. setosus (Tendrac) . .

15

14

5

7

3
3?

10

Q

40

40

J. upaia

1 3

7

0

°5

54

Sorex araneus (Shrew) ....
S. fodiens (Water-shrew) . .
ChrysochlorisCapensis (Cape
mole)

14
13

10

6
6

3

5?
5

5

14
17

5

46
48

39

Talpa Europcea (common
mole)

1?

6

Q

11

43

T. caeca (blind mole)

14

5

5

1 1

42

Condytura cristata (radiated
mole

3

6

7

48

Scalops (mole-shrew)

2

7

r.

Q

42

It is worthy of remark, in taking a compara-
tive glance at this list, that the length of the
tail in the different species is in exact accord-
ance with their habits, as far at least as we are
acquainted with them. Thus, in Tupaia, we

observe a tail as long as that of a squirrel, and
obviously for the same object, that of balanc-
ing the animal when taking leaps from one
branch to another ; and in the Water-shrew the
tail is lengthened to assist in swimming, for
which purpose it is also fringed on each side
with stiff hairs. Of the habits of the Condy-
tura* we know little, and of that little nothing
which accounts for the considerable proportion
of the tail.

Of the form of the different vertebrae in the
various groups of the Insectivora, little need
be said, as there are few circumstances con-
nected with these bones which bear materially
upon any physiological point. It may be ob-
served, however, that in the Talpida and the
Soricidtf the cervical vertebrae form large rings,
have strong transverse processes, and, except-
ing the second, do not possess any spinous
processes. In the Erinaceada, and particu-
larly in the Tenrec (Centenes) the transverse
processes are particularly large, and the rings
smaller than in the former families. The spi-
nous processes are also wanting in the dorsal
vertebrae of the mole.

The sternum offers some peculiarities
worthy of notice. In the mole the first ster-
nal bone is very large and compressed. To its
anterior pointed extremity the thick short
clavicles are attached, and further back to the
same bone, the first rib is articulated ; to the
second bone is fixed the second rib, and there
succeed to these three elongated bones of the
ordinary form, to each of which two pairs of
ribs are articulated ; then a small bone, to which
one pair of ribs is fixed, and then the xiphoid
bone, which is long and narrow.

In the Chrysochloris the first bone of the
sternum is equally compressed but less elevated ;
and the anterior half is furnished on the up-
per part with two small aliform processes,
which are concave, and support the first two
ribs, which are extremely broad; the long
slender clavicles are attached at its anterior
point; and then follow seven other oblong
pieces, and an elongated xiphoid bone, which
bears at its posterior extremity a semilunar car-
tilaginous dilatation.

The ribs in the mole and its congeners are
nearly all of the same length, giving that pe-
culiar cylindrical form to the body which cha-
racterises these animals, and which is so essen-
tial to their habits ; and in the Chrysochloris the
first rib is very much broader than the others.

But it is in the bones constituting the anterior
extremities, that the most remarkable and in-
teresting peculiarities exist in some of the
families of this group. In the mole especially,
the anterior extremity (Jig- 442) exhibits one of
the most extraordinary modifications to be found
in the whole of the Mammifera. The clavicle
is fully developed in the whole of the Insec-
tivora. In the mole (b) it offers the most

* From the name condyiura, given to this genus
by Illiger, it might be inferred that the tail is
furnished with knotty tuberosities ; this, however,
is only seen in dried specimens, which doubtless
furnished to Illiger the characters of the genus,
and suggested its name.

1NSECTIVORA.

997

F/-. 4-12

abnormal deviation from the usual construc-
tion. It is extremely short and broad, forming
in fact nearly a square ; about the middle of its
anterior margin a strong process rises, which
gives origin to the subclavian muscle, which in
this animal is greatly developed. It is articu-
lated, as usual, with the sternum by its interior
extremity, which may here be more properly
called its interior margin ; but by its external
margin it is connected moveably with the head
of the humerus, which connection is rendered
more solid towards the anterior part by a strong
ligament. Its connexion with the acromion of
the scapula is by a ligament merely, which
extends from the acromion to the posterior and
outer angle of the clavicles. In Condytura and
even in Scalops the construction of this bone is
on a similar type; but in Chrysochloris it is
long and slender as in the other Insectivora.

The scapula (a) in the mole is no less singu-
larly formed than the bone just described. It is
elongated to an extraordinary degree, being not
less than six times as long as it is broad at the
broadest part, which is at the superior extremity.
Towards the middle it is contracted and almost
cylindrical; and the spine, which runs nearly
the whole length of the bone, is at this part
almost effaced. The acromion, as before ob-
served, has only a ligamentous connexion with
the clavicle. In Condytura and Scalops the
construction of this bone is somewhat similar,
and in Chrysochloris it is also of considerable
length.

The humerus in the mole (fgs. 442, c, 443)
is of so extraordinary a form, that were it
examined alone, isolated from its natural con-
nexions, it would be impossible to detect

Fig. 443.

its true character. It is of a square form,
extremely broad at the superior part, where
it presents two articular surfaces; the an-
terior is very broad, slightly convex; the
posterior and internal is narrow, but more
convex than the former ; by the first it is
articulated to the clavicle, and by the latter
to the scapula. Between the former, which
may be considered as appertaining to the
greater tuberosity of the bone, and the head, is
a deep fossa. The body of the bone is short,
thick, and very broad, and is curved upwards,
so that its articulation with the forearm is
placed actually higher than the shoulder, and
the palm of the hand is consequently turned
outwards. In Chrysochloris the form of this
bone is not less remarkable. It is somewhat
longer than that of the mole ; its articulation
with the forearm constitutes half a sphere ; and
the inner condyle is so elongated and inclined
downwards, that the whole bone forms an arch
of which the convexity is turned outwards.
This condyle is articulated with a bone, which
must be considered as a most extraordinary
modification of the ospisiforme, which is as long
as the radius, so that in fact the forearm may be
said to be composed of three bones.

The bones of the forearm (JtgA42, d,e) in the
extraordinary animal which otters so many de-
viations from typical structure, the mole, are
no less remarkable than those of the shoulder.
The ulna is very broad and much flattened ; its
superior extremity is enlarged transversely, the
anterior surface concave, the posterior convex.
The radius is separated by a considerable in-
terval from the ulna throughout their length,
and the two bones are only united at the upper
extremity by a capsular ligament. But the
articular surfaces of the two bones are flat, and
the head of the radius is prolonged into a hook-
like process, forming a sort of radial olecranon,
so that rotation is impossible. The carpal bones
C/g.444) consist of two series of five in each, and
an additional bone of a very peculiar construc-
tion. This is a large sickle-shaped or falciform
bone, having the convex margin outwards ; it
extends from the carpal extremity of the radius
to the first metacarpal bone. It is this bone
which gives the great breadth to the hand,
which is so important to this animal in its
peculiar mode of life.

The phalanges of the fingers are very short,
and covered by the integument in such a
manner as to appear to belong to the meta-

Fig. 444.

998

INSECTIVORA.

carpal portion of the hand ; and it is only the
long sharp nails which extend beyond the skin,
and are externally visible.

The position then of the anterior extremity
of the animal is this : the humerus is so placed
that the inferior or distal extremity is the most
raised, so that the fore-arm is kept in a state
between pronation and supination, the elbow
raised, the radius and the thumb placed down-
wards, and the palm of the hand directed out-
wards. When to this we add the peculiar
flexion of the last phalanx of the fingers with
the enormous nails, we have a fossorial struc-
ture not equalled by any other in the whole
of the vertebrated animals, and only imitated
by the no less remarkable anomaly amongst
insects, the Gryllotalpa or mole-cricket.

In Chrysochtoris the third and fourth fingers
are united by one large powerful nail, and are
developed to an extraordinary size (fig- 445),

Fig. 445.

the fifth finger being reduced to a minute ru-
diment ; and the carpal bones are placed in an
abrupt curve, so that the outer side of the fifth

finger approaches the first. The os pmforme as-
sumes also a peculiar development, being veiy
much elongated, rises in the direction of the
forearm, and is actually articulated with the
internal condyle of the humerus.

The pelvis in the Talpida and Soricid<e is
extremely long. The ilia are narrow and
pointed at the anterior part. In the last-named
family, the pubis and the ischium are especially
long and narrow. In Chrysochloris, on the
contrary, the ischium is very broad.

The femur offers but few and unimportant
particularities amongst the Insectivora, unless
it be that there is in the mole and Chrysochloris
a sort of third trochanter; a process which is also
found in some of the lower Quadrumana, and
in some other of the Mammifera. The fibula
is united to the tibia for nearly the inferior third
of their length, in the Talpufa, the Soricida,
and the Erinaceada. In the mole this union
is to a greater extent than perhaps in any other
animal of the Mammiferous class.

The hinder feet in the whole of this order
are plantigrade. In the mole, as Daubenton
and Meckel have observed, there is an addi-
tional tarsal bone, to those which are ordinarily
found. It is of considerable size, and seems to
answer to the falciform bone of the anterior
extremities already described. It is of an
uniform shape, of considerable size, and is arti-
culated between the scaphoid and the first
cuneiform bone, and extends forwards along
the first metatarsal.

II. Muscles. — The extraordinary develope-
ment of the bones of the anterior extremity in
the mole, will, of course, be associated with
a no less remarkable structure in the muscles
of the same part ; and the known habits of the
animal will account equally for the necessity
of such a structure in both. I give a figure
of the muscles of the anterior extremity and
of the anterior part of the trunk from Carus.
(Fig. 446.)

Fig. 446.

INSECTIVORA.

999

The cervical portion of the serratus magnw
is simple, excessively thick and swelling, and
is attached only to the posterior vertebrae. The
trapezius consists only of two bundles of
fleshy fibres, which arise from the lumbar ver-
tebrae, and are inserted into the posterior ex-
tremities of the long and narrow scapulae; and
as these fasciculi are nearly parallel, their
action would be rather to separate than to ap-
proximate the posterior parts of these bones,
were it not for a strong transverse ligament
which holds them together. Their application
consists in moving the anterior part of the body
upwards. The scapular attachments of the
rhomboideus are principally to this transverse
ligament of the two scapulae, and as it is in-
serted into a sort of ossified modification of a
cervical ligament, its office consists in raising
the head with great force. The levator scapula
is wanting ; its existence would be obviously
useless. The pectoralis minor is very slender ;
it is attached to the anterior parts of the first
ribs, and to the ligament, already mentioned,
•which joins the clavicle to the scapula. There
are also two muscles arising from the anterior
part of the sternum, and inserted into the large
head of the clavicles.

The most important muscles of the humerus
are the pectoralis major, the latissimus dorsi,
and the teres major, all of which are of great
size ; and it is by means of these muscles that
the astonishing efforts of the animal are made
in excavating his passages, and throwing the
earth behind him. The pectoralis major is of
extraordinary thickness. It is formed of six
portions, which are all of them inserted into
the broad quadrate portion of the humerus.
Four of these portions arise from the sternum,
the fifth from the clavicle ; and the sixth passes
across transversely from one arm to the other.
The latissimus dorsi is also of considerable size,
and is inserted into the posterior surface of the
quadrate portion of the humerus. The ttres
major, which is of enormous thickness, is in-
serted near the former muscle.

The other muscles of the anterior extremity
do not require particular description.

There is one peculiarity in the muscular sys-
tem which deserves special notice; it is the
enormous developement of the panniculus car-
nosus in the hedgehog, by which it is enabled
to roll itself up in a ball with such astonishing

force as to afford mth its spiny covering a
complete protection against its most powerful
antagonists. I proceed to describe this ap-
paratus and its uses.

As this muscular apparatus has no attach-
ment but to the skin, it changes its position
with every movement of the integument ; and
it is therefore necessary to consider it under
the various relations which it assumes in the
different positions of the animal. Considering
it then, in the first place, as rolled up in a ball
(Jig. 447), either for defence or during repose,

Fig. 447.

the whole body is enveloped beneath the skin
by a strong sac or covering, consisting of a
mass of fleshy and concentric muscular fibres,
of an oval form. All these fibres are attached
intimately to the skin, and even to the base of
the spines with which it is every where furnished,
so that it is even difficult to detach the fibres in
dissection. The thickest part of this fleshy sac
is at the lower margin or mouth of the sac,
at which part it forms a sort of sphincter, com-
posed of orbicular muscular fibres. On the
other hand, when the hedge-hog is unrolled,
and at its full length (fig. 448), the muscle in
question totally changes its figure and relations.
The muscle now lies over the back, forming an
oval covering, the middle of which is very thin,

Fig. 448.

1000

INSECTIVORA.

and the circumference exceedingly thick and
somewhat raised. To different portions of this
circumference of the muscular covering are
attached several accessory muscles. Anteriorly
there are two pairs ; one arising from the me-
dian line and inserted into the nasal bone ; the
other, more external, apparently confounded at
its origin with the external orbicular fibres, is
inserted into the side of the nose and incisive
bones. Posteriorly a pair of broad muscles,
of a pyramidal form, arise from the posterior
part of the fleshy circumference, and are in^
serted into the side of the tail towards the ex-
tremity.

On the ventral aspect there are also several
portions of muscle, belonging to the same ap-
paratus. There is one beneath the throat, aris-
ing from the anterior part of the thorax, under
the skin, and is inserted about the lateral parts
of the head near the ears. Another arises from
the median line of the sternum, and passes
obliquely forwards over the shoulders, in front
of them, to join the margin of the great or-
bicular muscle before described. There is
another ventral portion which has a very ex-
tended connexion. It is attached around the
anus, to the lateral parts of the tail and neigh-
bouring parts, extends over the whole surface
of the abdomen, and then divides into two
portions; one internal, and larger than the other,
passes under the axilla, and is inserted into
the superior and interior part of the humerus;
the other, external, passes laterally upwards, to
be inserted into the margin of the great or-
bicular muscle near the neck. The muscles
hitherto described lie superficially; but there
are others which are seated underneath the
great muscle of the back. One arises from the
side of the head, being attached to the meatus
auditorius on each side, and loses itself in the
anterior point of the orbicular muscle. There
is also a thin layer of fibres lying beneath the
great muscle, of which the anterior are attached
to the superior interior portion of the humerus,
and the posterior to the third ventral muscle
already mentioned.

We have here a very extensive and a very
powerful apparatus, and it now becomes ne-
cessary to consider its application. When the
hedgehog is rolled up in a ball, it is com-
pletely enveloped, as regards all the upper and
lateral parts of the body, in the great orbicular
muscle. When once brought into this position
the simple contraction of the thick circum-
ference of the muscle, which forms a true
sphincter, is sufficient to retain it. If the ani-
mal unrolls itself, the disc of the great muscle
contracts whilst the circumference is relaxed,
allowing the exit of the feet and the uncover-
ing of the belly and sides: then the whole
muscle contracts together, and lies in a mass
on the back. By this universal contraction,
the necessary muscles become stretched, and
in a condition to perform their several offices ;
by the contraction of the anterior ones the head,
and by that of the posterior the tail, is raised,
whilst those which lie beneath raise the head
and neck together, and the animal is now
ready for progression. On the other hand, on

the apprehension of danger, or wheti reposing,
it rolls itself into a ball by the following pro-
cess. The orbicular muscle relaxes, and the
muscles extending from it to the head and to
the tail extend it in those directions, whilst the
deap-seated transverse muscles which are at-
tached to the external lateral portions, and lie
on the belly, bring this part of the circum-
ference downwards. At the same time the
head is brought downwards towards the breast
by the ordinary flexion of the head, and by the
cutaneous muscles of the neck already de-
scribed; the tail and the hinder legs are brought
forwards under the belly, and the flexors of the
limbs contract. The great orbicular muscle
passes downwards over the sides, then contracts
at the circumference, and forms a sort of sac or
purse, enveloping the whole body and limbs.

III. Digestive organs. — It is, of course, in
the structure of the digestive organs, and par-
ticularly in that of the teeth, that we find the
distinguishing characters of the whole order;
yet so nearly do these organs in the Insecti-
vora approximate to those in the insectivorous
division of the Cheiroptera, that it would not
have been possible to separate the two groups,
had there been no other important points of
distinction. From the insectivorous Quadru-
mana they are distinguished by the planti-
grade character of the posterior extremities;
from the bats by the whole structure of the
limbs, and from all the true Carnivora by the
tuberculated teeth.

There is no inconsiderable difficulty in as-
signing the various anterior teeth in the Insec^
tivora to their proper classes. In most of the
genera, according to the statement of both the
Cuviers and others, there are no canine teeth,
and the false molares are very numerous ; but
it is in many cases doubtful whether the an-
terior false molares, as they are termed by
these anatomists, be not theoretically canines
modified in their form. On this point, how-
ever, there is no possibility of coming to a
satisfactory conclusion, as every one will at
last form his own opinion on each case; I shall
therefore follow the arrangement of Frederic
Cuvier as the most generally known, and,
upon the whole, by for the best authority on
the teeth of the Mammifera.

The incisive teeth vary greatly in the dif-
ferent genera. In Mygalc, in Scalops, and in
Condytura, there is in the upper jaw but a
single incisor on each side, which is very strong
and of a triangular form. In the first of these
genera it is somewhat curved downwards and
backwards, and slightly resembles that of some
Ilodentia. In Snrex (fig- 449) it is also single,
very strong, curved, and similar to the canine
tooth in the Carnivora, but furnished with a
strong tooth-like process posteriorly, appearing
almost like a distinct tooth.

In Talpa (Jig. 441) there are three superior
incisores on each side, which are small with
cutting edges, like those of the Carnivora. In
Chrysochloris (fig. 450), the single superior
incisor is curved, convergent, obliquely trun-
cate and pointed; and in Erinaccits (fig.45l)
there are three pairs, of which the first is large,

INSECTIVORA.

1001

Fig. 45 1 . Erinaceus.

Fig. 450. Chrysochloris.

Fig. 452. Tupaia.

1 2

obtuse, and strong, separated by a considerable
interval from its fellow, and convergent with
it. The others are small and resemble false
molares. In Tupaia (fg. 452) these teeth
are two on each side, distant from each other,
and from the first false molar. The inferior
incisores also vary greatly in their form and
number. In Scalops there are two, the first
small, the second larger and resembling in form
a canine tooth. In Condytura there are two,
rounded in front, flattened behind. In Tulpa
there are four similar to those of the upper jaw,
and in Sorex there is one only of a very pecu-
liar form : it is very long from the anterior to
the posterior part, somewhat hooked, pointed,
and, in_ some species, the edge is notched or

trifid. There are no true canines, according to
the opinion of Frederick Cuvier, in any of
these animals, excepting Candy tura, Tulpa t
(in which they exist in the upper jaw only)
Centenes, and Tvpaia. The first tooth be-
yond the incisores, considered by Fred. Cuvier
as the first false molar in the lower jaw in the
mole, is by Baron Cuvier termed the canine. In
Centenes these teeth are of the normal form ;
and in fact the general arrrangement of the
teeth in this genus indicates a marked approach
towards the Carnivora. In Condytura the su-
perior canine is strong and large ; the inferior
merely rudimentary.

The molares, as in the other Zoophaga, are
divided into false and true. Those of the

1002

INSECTIVORA.

former class are very numerous and of very
various form in the different genera, and the
Great diversity of number in the molar teeth
depends in most cases upon these, the true
molares being but three on each side both
above and below in all the genera, excepting in
Chrysochloris, in which they are f:|, in Eri-
naceus, in which they are *:$, and in Centenes
\:\. In Chrysochloris the true molares are
very curiously and beautifully formed : they
are much compressed from before backwards,
of a three-sided form, each of the angles ter-
minating in a sharp elevated point; thus, in
those of the upper jaw, there are two situated
externally and one internally, and in the lower
jaw one externally and two internally. The
whole of the true molares, in all the Insecti-
vora, are formed of three-sided prisms, either
single or double, and surmounted by acute
tubercles.

The salivary glands are generally much de-
veloped in the Insectivora. In the hedgehog
the parotids are larger than the submaxillary ;
the sublingual are placed in two rows, of
which the larger is situate nearest to the lower
jaw. In the mole these glands are very large;
the parotids are of an oblong shape, and the
maxillary are formed of several rounded and
detached lobes. In Sorex the maxillary glands
are of larger size than the parotids, and the
latter are situated very low to accommodate
the oblique direction of the auditory canal.

The form of the stomach in this Order of
animals is perfectly simple, and does not greatly
vary in the different genera. It is situated
transversely with regard to the axis of the body,
is somewhat elongated, and the two orifices are
distant from each other, as in many of the
Carnivora, and in the insectivorous bats.
The cardiac pouch is generally distinct and
rounded ; the pyloric extremity, on the con-
trary, is conical and perfectly even. In Erina-
ceus the cardiac point is considerable, the en-
trance to the oesophagus being at no great dis-
tance from the pylorus ; and the internal coat
forms numerous rugae and folds. This form of
the stomach and the existence of plicae must be
considered as indicating an aberration from the
insectivorous type, and a certain degree of ap-
titude for the digestion of vegetable matters,
and we find accordingly that this, with a slight
exception or two, is the only family of the
Insectivora which can exist upon any but the
most exclusive animal aliment. The mole, the
Chrysochloris, and all their congeners, are in
this latter case ; but the hedgehog, as is well
known, will readily eat various vegetable sub-
stances, and often digs under the common
plantain for the purpose of obtaining the roots,
of which it appeal's to be very fond. The sto-
mach varies a little in its form in the different
genera of the Soricida. In the great shrew of
India it is transverse, the pyloric portion coni-
cal, of moderate dimensions, the cardiac pouch
small and the two orifices distant; a form
which indicates an exclusive aptitude for insect
food ; but it would appear that the water-shrews
(Hydrosorex) must occasionally have recourse
to some kind of vegetable diet, as the pyloric

portion is so much elongated as to resemble in
some degree that of the Pteropida or fruit-
eating Cheiroptera, exhibited in fig. 287, vol. i.
p. 600. In the mole the oesophagus enters at
about the middle of its anterior margin, and
the lesser curvature is nearly straight to the
pylorus. The membranes are extremely deli-
cate and almost transparent. The form is es-
sentially similar in Chrysochloris and in Con-
dytura. The stomach of Tupaia, according to
the Baron Cuvier, is of a globular form.

The intestinal canal is upon the whole re-
markably short in the Insectivora. There are
some exceptions to this rule, but the only one
bearing upon a difference of aliment is that of
the hedgehog, which, as has been before ob-
served, lives partially upon vegetable matters.
In this animal it is, with regard to the length
of the body, as 6.6 to 1 . In Talpa and Centenes
this proportion is even exceeded, but it is com-
pensated for by the extreme narrowness of the
canal ; the diameter of which is to its length,
in the mole, as 1 to 82 ; whilst in the hedge-
hog it is as 1 to 58. In Sorex its length is to
its diameter only as about 3 to 1, or a little
more. There is no coecum known to exist in
any of the Insectivora. Cuvier queries whe-
ther Tupaia be not an exception, but this we
have at present no means of ascertaining. The
liver is in general fully developed in all its
parts; there are the principal lobe, to which
the gall-bladder is attached, with a notch
answering to the suspensory ligament, a right
and a left lobe, and two smaller lobes or /o-
buli, a right and a left. The whole of these
parts are generally found, but varying without
any known law, or any ascertained relation
to functional peculiarity. In the hedgehog
and in the mole the left lobule is composed
of two portions, a cardiac and a pyloric, as in
the Rodentia. In Tupaia, according to the state-
ment of Cuvier, the three portions into which
the liver is divided belong to the principal lobe;
there is no right or left lobe, and the right lo-
bule is also wanting. The gall-bladder is for
the most part of considerable size. In the
hedgehog its fundus appears beyond the free
margin of the liver, and is supported by a
process of falciform ligament. In the Tenrec,
on the contrary, it is as it were incrusted by
the substance of the right portion of the prin-
cipal lobe.

IV. Nervous system. — The form and propor-
tions of the brain in some of the Insectivora ex-
hibit a degree of developement not materially
superior to that of the higher Carnivora; whilst
others, and especially the mole, have the same
higher proportion which are found in the Chei-
roptera : thus in the hedgehog the volume of
the brain is to that of the body as 1 to 168;
whilst in the mole it is as 1 to 36. The pro-
portion of the cerebellum to the cerebrum in
the latter animal, however, indicates a consi-
derable developement of the sexual functions,
being as 1 to 4£. Supposing the theories of
many modern physiologists to be correct, this
fact is in perfect accordance with the neces-
sities of the animal, whose means of obtaining
access to the opposite sex are extremely diffi-

INSECTIVORA.

1003

cult, and require intense ardour and perseve-
rance to effect this object.

The most remarkable and interesting pecu-
liarities which are to be met with in the struc-
ture of any of the Mammalia are to be found
in the eye of the mole, and doubtless of the
nearly allied forms of Chrysochloris and the
other subterranean species. In these, in order
to meet the requirements of their habits, the
organ of sight is reduced to a mere rudiment,
whilst those of hearing and of smell are deve-
loped to an extraordinary degree; and the
theory of the balance of organs can scarcely
boast of a stronger support in the whole range
of animal organization than in this instance.

The question whether the mole possesses vi-
sion has been long and often debated. With-
out entering into an unnecessary examination
of all that has been said on both sides of the
question, it may be well to observe that the
principal argument which has been urged on
the negative is derived from the absence of an
optic nerve. That this animal, at least our
common species, does possess the faculty of
vision to a certain degree cannot, however, be
disproved, whatever may be the means by
which the sense is communicated, that is to
say, whatever the nerve may be which supplies
the place of the true optic nerve ; and the ex-
periments of Henri le Court and Geoffroi St.
Hilaire* would well nigh go to prove the
affirmative of the proposition. It has been
urged then that an optic nerve is absolutely
necessary to the existence of vision; and that,
therefore, either the mole has a true optic nerve,
or that it does not possess vision. There have
indeed been three classes of observers on this
point ; those who maintain that the mole sees,
and that it possesses an optic nerve ; those who
contend that it is blind, and possesses no such
nerve ; and others have ventured to agree with
the former as to its power of vision, and with
the latter in denying the existence of the optic
nerve.

The eye of the mole is extremely small, but
differs not materially in its structure from that
of other animals. The pupil is elliptic and
vertical; the cornea even more convex than that
of birds; there is a sclerotic and a true choroid.
The crystalline lens is perfect, and much more
convex than in most of the Mammalia ; and
the eye-ball, emptied of its contents, exhibits
at the base a lining of a whitish colour. " In
an injected subject," says Geoffroi, " the cen-
tral artery of the retina was distinctly seen."
Whether there be or not a true retina will be
variously solved according to the views of dif-
ferent physiologists. If the nerve, whatever it
may be, which takes here the place of the
optic nerve, be really the seat of the sense of
vision, there seems to be no objection to con-
sider its expansion, upon which the pictures of
objects are impressed, as a retina ; giving the
name rather to the physiological than to the
anatomical character of the part ; but be this
as it may, from the posterior part of this minute

eye there passes a distinct branch of a nerve.
Perhaps, after all, the name and analogy of
this nerve will be viewed differently according
to the general views of organic developement
entertained by different physiologists. Geoffrey
considers it as the optic nerve, notwithstanding
it has no connexion with that part of the brain
which in all other cases is in immediate com-
munication with it; and he founds this opinion
upon the theory that all organs are developed
from without. His words are as follow: —
" Qu'est ce que ce nerf ? La monstruosite et
la nouvelle theorie sur le point de depart des
developpemens organiques assure ma marche :
appuye sur ces deux fanaux, aujourd'hui heu-
reusement importes dans 1'histoire encore si
obscure des premieres formations je ne doute
pas que ce ne soit le nerf optique. C'est ce
nerf, parceque cet appareil, qui est au complet
comme globe oculaire, a du se former de toutes
ses dependances jusqu'a I'empechement qui en
arrete le cours. Cette determination ne sauroit
etre douteuse pour qui reconnait que les or-
ganes naissent a la circonj'erence de Vetre, d'ou
ils envoient leurs rameaux s'embrancher au plus
pres dans le centre.*

Amongst those who assert that the mole pos-
sesses a true optic nerve is Miiller. His state-
ment is so brief, and, it may be said, so unsa-
tisfactory, that it can scarcely be considered as
sufficient to outweigh the carefully formed opi-
nion of many who differ from him. His state-
ment, as given in Dr. Baly's translation of his
admirable book, is as follows: — " Some ani-
mals, though provided with eyes — for instance,
the mole and the proteus anguinus — have been
said to want the optic nerves; the sense of
vision being then placed in the ophthalmic
branch of the fifth nerve. This statement has
arisen, in the case of the mole, from inaccuracy
in the anatomical examination ; and the same
is the case probably in the Proteus. The mole
has an uncommonly small optic nerve, as Dr.
Henle has shewn me."f On the other hand,
Serres, Gall, Desmoulins, and others have
agreed in delaring that there is no nerve passing '
from the optic lobes to the eye ; and Dr. Todd
has recently verified this statement, and traced
the nerve which does supply this organ, which
he finds to be the ophthalmic branch of the
fifth pair. I give an enlarged view of a dissec-
tion of this nerve, drawn by Mr. Bowman.
fF^.453.)

a is the fifth nerve within the cranium, b
the Gasserian ganglion, c the inferior maxillary
nerve, d the ophthalmic nerve going to the eye
(e,) ./'the superior maxillary nerve, g branch of
the ophthalmic, supplying the side of the nose.
Dr. Todd in a letter to me says, " I have
been lately looking at the point about the optic
nerve in the mole. I can see an optic commis-
sure, but no optic nerve beyond it, and I can
very distinctly trace a branch [the ophthalmic]
of the fifth to the eye. I carefully searched to
see if a second nerve were bound up in the
cellular sheath with it, but could find none.

* Geoff. St. Ililaire, Cours d'Hist. Nat. des Mam.
lev. 16,

* Conrs d'Hist. Nat. des Mammif. 16 Ie9. p. 27.
t Miillerfs Phys. by Baly, p. 767.

1004

INSECTIVORA.

The chiasma is very distinct, without a trace of
a nerve proceeding from it."

Fig. 453.

The organ of hearing in the mole is so con-
structed as to afford the greatest possible deli-
cacy and acuteness of this important sense, and
thus to counterbalance the deficiency in that of
sight. It would indeed appear that the mass
of compact bone constituting the petrous por-
tion of the temporal, which surrounds the laby-
rinth in most of the Mammalia, must more or
less diminish the powers of hearing, for we find
it deficient in many animals, which from their
habits require this sense to be in the greatest
perfection. Thus, in the mole, the semicircular
canals are free and visible within the cranium,
without any preparation; and the parietes of
the cochlea itself are almost as cellular and
loose as we find in birds.

The ear of the mole possesses no concha ; it
is small in the shrews; and in the water-shrews
( Hydrosorex ) the external meatus is closed at
the will of the animal by means of the anti-
tragus; a provision obviously essential to its
aquatic habits.

When it is considered that the sense of
vision is only available on the rare occasions
of the appearance of the mole on the surface,
and then only for very limited objects, and that
all its intimations of danger, and its only guide
to the opposite sex, are by means of the sense of
hearing, the necessity for this extraordinary deve-
lopement of that sense at the expense of that of
sight becomes obvious. And as, from the nature
and situation of its food and its means of pro-
curing it, the sense of smell is equally neces-
sary for effecting this object, we find that the
olfactory organ is also of considerable volume.
The structure of the nose itself is highly curious
and admirably suited to the habits of the ani-

mal. The cartilages of the nose are elongated
into a tube or trunk, which extends far beyond
the osseous basis, and is supported by a very
delicate moveable bone, which is represented
in the figure of the cranium of the mole at
fig. 441. It is furnished with a muscular appa-
ratus of considerable complexity (see/g. 446),
consisting of no less than four pairs of muscles,
which arise from above the ears, and passing
forwards are inserted by separate tendons into
the circumference of the extremity of the carti-
laginous snout. This structure is of the utmost
advantage to the animal in its subterranean
search after worms and insects.

There is no order of Mammalia in which a
greater contrast is exhibited in the external
covering of the body than in the different
groups of the Insectivora. The porcupine
and the mouse, amongst the Rodent ia, do not
offer a more remarkable contrast in this respect
than do the two families of the Erinaceada and
the Talpida. The habits of the hedgehog de-
pending for its defence upon the panoply of
armour which it presents to its enemies, when
rolled up in a compact ball by the muscular
apparatus already described, it is furnished on
all the upper and lateral parts of the body
with hard sharp spines or quills. Fig. 454

Fig. 454.

is taken from a drawing by William Bell,
engraved in the Hunterian Catalogue, vol. iii.
from which also the following description is
borrowed: — " On the cut edge of the skin
may be seen the roots and sockets of the quills,
extending to different depths from the surface,
according to the period of their growth : the
newly formed ones are lodged deep and ter-
minate in a broad basis, the pulp being large
and active, and the cavity containing it of cor-
responding size; but as the growth of the quill
proceeds, the reflected integument forming the
socket contracts, and gradually draws the quill
nearer the surface; the pulp is at the same time
progressively absorbed, and the base of the

INSECTIVORA.

1005

in consequence gradually increases in size,
so that it is at last seen to be attached to the
surface of the skin by a very narrow neck,
below which the remains of the socket and
theca are seen in the form of a small bulb."
( t'ig. 454, a.) " A completely formed prickle or
quill cut longitudinally and magnified, shewing
that it is hollow and filled with a pithy sub-
stance, which is transversely disposed, so as to
divide the cavity into many sections." But the
defence of the animal against attack is not the
only object of this modification of the hair.
I have more than once seen a hedgehog run to
the edge of a precipitous descent, and without
a moment's hesitation throw itself over, rolling
itself up at the same instant, and on reaching
the bottom run off perfectly uninjured. It is
unnecessary to point out how perfectly this
habit is provided for by the elasticity of the
spines, dependent upon their structure, as ex-
hibited in the figure. The under parts of the
body and the limbs are covered with ordinary
hair. The Tenrec and other Erinaceada re-
semble the hedgehog in these respects, and
in some species the quills and hair are inter-
mixed.

The mole, on the other hand, possesses hair
-of the softest and most flexible description.
In its subterranean galleries, which are not
large enough to allow it to turn round, it must
often be obliged to retreat backwards ; and the
hair therefore is so constructed as to lie equally
smooth in every direction. This has been sup-
posed to be effected merely by its growing ex-
actly perpendicular to the surface of the body ;
but it is in fact still more effectually provided
for by a remarkable form of the hair itself.
Each hair consists of three or four broader
portions connected by intervening portions of
extreme tenuity; so that there are several
points in the length of each hair which pre-
sent no appreciable resistance. The hair
of the shrews is similarly constructed, and in
each case it is to this structure that the pecu-
liar and beautiful softness which characterizes
it is owing. It is worthy of remark that the
colouring matter of the hair exists only in the
broader portions, the intermediate parts being
wholly colourless.

V. Organs of reproduction. — The repro-
ductive organs of the Insectivora offer, in
several instances, some remarkable peculiari-
ties. The subterranean life of many of these
animals renders the meeting of the sexes in
their natural haunts a matter of almost for-
tuitous occurrence ; and it is therefore neces-
sary that the sexual desire should in the male
be sufficiently powerful to force him as it were
to seek and pursue the other sex through all
the difficulties and disadvantages occasioned
by their peculiar habits. Hence we find that
in most of them the male organs are developed
to an extraordinary degree; and in the mole
the enlargement of the testes as the season of
pairing advances is as remarkable as it is in the
sparrow or in any other example of this sea-
sonal increase of those organs. Two incom-
patible statements have been made respecting
the testes in the mole. Cuvier asserts that

they make their appearance externally during
the season of propagation. Blumenbach de-
clares that they belong to the true testiconda,
with the hedgehog, &c. The truth is, as de-
monstrated with his usual ingenuity by Geof-
roy St. Hilaire, that the testicles of the mole
never make their appearance externally, al-
though during the season of their greatest de-
velopement they would do so but for the
peculiar construction of the parts in which the
organs of generation in this animal are con-
tained; for the abdominal cavity extends be-
yond the pelvis, as far as the first four coccy-
geal vertebrae, which in fact do not, properly
speaking, in any degree constitute the tail,
which is formed only of the posterior seven
vertebrse, and the testes during the season are
protruded so as to lie concealed under this
portion of the caudal division of the spine,
which forms as it were a continuation of the
upper part of the pelvis. In the hedgehog the
testes remain within the abdomen excepting
during the spring, and even then they are but
little protruded. The object of their being
thus generally protected is obvious : in the
hedgehog these organs, if external, would be
exposed to danger from the act of rolling itself
up, and in the mole and its congeners they
would interfere with the act of excavating
their subterranean passages. The penis in the
mole possesses a remarkable peculiarity, which
doubtless has reference to the condition of the
female organ presently to be described. It
consists in a small terminal bony appendage,
covered but slightly by integument; it was
considered by Daubenton as the os penis, but
from its different situation it may be doubtful
perhaps if it be in truth analogous to that part.

The male organs are in the hedgehog deve-
loped to an extraordinary degree, more espe-
cially the vesicula seminales. The testes are of
an oval form, smooth, and although large in
proportion to the size of the animal, are much
smaller than the vesiculae seminales ; these are
of enormous size, each consisting of four or
five fascicles of extremely convoluted tubes,
the membranous parietes of which are ex-
tremely thin and fragile. Cowper's glands and
the prostatic gland are also of considerable size
in this animal. The orifices of the vasa defe-
rentia, vesiculee seminales, prostatic gland, and
Cowper's glands all open within the foramen
ccecum of the urethra.

The female organs in the mole offer some
peculiarities which deserve more attention than
they have hitherto received.

In the first place, it appears that in this
animal the urinary and genital orifices are

Fig. 455.

INSECTIVOUA.

wholly distinct. The clitoris, (fig. 455, c,)
which is of considerable length, and very much
resembles the penis of the male, is pierced for
the passage of the urine, and thus constitutes
a true urinary penis. Beyond this is a trans-
verse slit of a slightly crescentic form, (Jig.
455, 2), which constitutes the opening of the
vagina. There are none of those duplicatures
of the integument which in other Mammalia
constitute the labia and nympha, but the skin
is smooth. But one of the most curious
points in the structure of these parts is that
in the virgin state this vaginal aperture does
not exist, (fig. 455, 1,) the skin being per-
fectly and tightly drawn over the entrance ; so
that there are in this state but two openings, the
urethral and the intestinal. So perfectly is this
the case that it is very difficult to know a virgin
female mole from the male by mere external

examination. As this covering is so tense, the
utility of the little bone at the extremity of the
penis in the male is very obvious, and its
pointed and tapering form is at once accounted
for : it is clearly intended to perforate this tense
covering to the vagina.

Another peculiarity in this animal is that the
abdominal cavity being extended greatly be-
yond the pelvis, the vagina, the rectum, and
the urinary passage terminate considerably fur-
ther back than in other animals. The opening
of the rectum is opposite to the articulation of
the fourth with the fifth caudal vertebra.

The uterus is of considerable size in the mole,
and its cornua much convoluted.

For BrBLioGRAPH v, see that of MAMMALIA.
(T. Bell.)

ANALYTICAL INDEX

TO THE

SECOND VOLUME,

DIAPHRAGM (in anatomy generally), I
Diaphragm (in human anatomy), 1

costal, upper, true or greater muscle, 9
septum transversum, 2
centrum tendineum, cordiform tendon, 3
ligamentum arcuatum —

externum, S
internum, 3

vertebral or smaller muscle, crura pillars or appen-
dices, 3
foramina or openings, 3

foramen quadratum s. venosum, 9
elipticum s. oesophageum, 3
aorticum, 3

other smaller foramina, 4
relations to the pleurae, peritonaeum, &c. 4
arteries, 4
veins, 4
lymphatics, 4
nerves, 4
uses, 4

malformations and diseases, 6
absence, 6
openings, 6
ulcers, 6
•wounds, 6
rupture, 6
inflammation, 6

gangrene, collections of pus, tumours, &c. 6
cartilaginous and osseous deposits, 8
displacement from ascites, &c. 6
Digestion, 6

I. Description of the organs of digestion, 7

mouth with its appendages, the lips, &c. 8
teeth, 8

salivary glands, 8
oesophagus and deglutition, 8

stomach, 9

intestinal canal, 10

peculiarities of the digestive organs in different
classes, II

II. An account of the nature of the substances usually

employed as food, 12
animal compounds, 13
vegetable substances, 13
liquids, 14
condiments, U
medicaments, 15

III. An account of the changes which the food ex-

periences in the process of digestion, 15
chymification, 16
physical and chemical properties of the gastric

juice, 1?
chylincation, 19

analysis of chyle, 19

IV. Theory of digestion, 21

V. Peculiar affections of the digestive organs, 25
Digestive canal (comparative anatomy), 27

I. Polygastrica, 28
Echinodermata, SO

systematic arrangement, 30

I. Tegumentary system, 31

in the AsteVias, 31
in the Echini, 32
in the Holothuriae, 33

II. Organs of motion, 34
in Asterias, 34

Echinodermata (continued).
in Echini, 35
in Holothuriae, 36

III. Digestive organs, 36
in Asterias, 36

in Echini, 38

in Holothuriae, 39

IV. Respiratory organs, 40
in Asterias, 40

in the Echini, 41
in Holothnriae, 41

V. Vascular system, 4 1

in the Asterias, 41

in the Echini, 43

in the Holothuriae, 43

VI. Nervous system, 44

VII. Generative organs, 44
in the Asterias, 45

in the Echini, 45
in Holothuriae, 45

VIII. Regeneration of lost parts, 45
Edentata, 46

osseous system, 48

skull, 48

vertebral column, 49

pelvis, 50

anterior extremity, 5O

posterior extremity, 50
of the Edentata proper, 51

digestive organs, 53

organs of circulation, 54

tegumentary system, 54
Elasticity, 55

general remarks, laws, &c. 56

tissues of the body in the order of their elasticity, 58
yellow fibrous tissue, 58
cartilage, 58
fibro-cartilaee, 58
skin, 59

cellular tissue, 59
muscle, 59
bone, 59

mucous membrane, 59
serous membrane, 60
nervous matter, 60
fibrous membrane, 60

instances in which elasticity plays an important part
in the mechanism of organized beings, 60

in the protection of the body and its parts, 60

as a substitute for muscular contraction, 61

as preserving the patulous condition of certain
outlets, 61

as subservient to locomotion, or movement gene-
rally, 61

as a means of dividing or transferring muscular
force, 62

converting occasional into conti-
nued forces, 62

Elbow, fold or bend of the arm, 62
skin and subcutaneous tissue, 63
veins, 63
nerves, 64
aponeurosis, 64
brachial artery, 64
development, 64
varieties, 65

selection of a vein for phlebotomy, 65

1008

ANALYTICAL INDEX.

Elbow, articulation of the, 65

bones, 65

ligaments, 66

motions, 67

lateral motion, 67
Elbow-joint, abnormal conditions of the, 67

I. Accidents, 68

simple fractures, 68

of the humerus and its condyles, 68
of the ulna, 69
of the olecranon, 69
luxations, 69

of both bones of the fore-arm back-
wards, 69

of the bones of the fore-arm laterally, 71
backwards
and outwards, 72

backwards
and inwards, 72

of the ulna alone directly backwards, 72
upper extremity of the radius
from the humerus and ulna, 72

of the radius forwards, 73

radius alone laterally, 73
radius alone backwards, 74
subluxation of the upper extiemity of the radius
with elongation of the coronary ligament, 74
congenital or original, of the upper head of the
radius backward, 75

II. Diseases, 77

of thesynovial membrane, synovitis, 77
of the cartilages — inflammation, softening, ab-
sorption, 77

of the bones — caries, elastic white swelling, 78
rheumatism, 79
Electricity, animal, 81
electrical fishes, 81
circumstances under which discharges from electrical

fishes take place, 82

motions of the fish in the act of discharging, 83
physiological effects of the dischaige, 83
inagnetical effects of the discharge, 8 i
chemical effects of the discharge, 86
results of experiments on the transmission of the dis-
charge through various conducting bodies, 86
production of a spark and evolution of heat, 87
anatomy of the electrical organs, 87
in the uupedo, 88
in the gy mnotus, 91
in the silurus, 53
analogies of animal electricity, 93
manifestations of common electricity in animal sub-
stances and in living animals, 95
uses of animal electricity, 97
Enccjihalon, 98
End3*mosis, 98

measurement of the amount of endosmosis, 98
strength of endosmosis, 98
effects of temperature, 100
explanation of the phenomena, 100
circumstances in which endosmosis occurs, 110
EnUzca. Ill

definition, 111

primary division into three classes— Protelmintha,

Sterelmintha, and Ccelelmintha, ill
families of the first class, Protelmintha:
Cercariadae, 111
Spermatozoa, 111
Vibrionidse, 113
Trichina spiralis, 113
families of the second class, Sterelminlha, equivalent

to the Orders of Rudolphi, 114
Cystica, 115
Cestoidea, 116
Trematoda, 116
Acanthocephala, 116

families of the third class, Coelelmintha, .116
Nematoidea, 116
Acanthotheca, 116
.description of species of human entozoa belonging to

the above Orders, 117

Acephalocystis endogena, Pill-box Hydatid, 1 17
Echinococcus hominis, 117
Cysticercus cellulosa, 118
Bothriocephalus latus, 120
Taenia solium, 120
Distoma hepaticum, 121
Polystoma pinguicola, 121

venarum, 121
Diplostomum volvens, 121
Filiaria Mt-dincusis, 102

oculi hmnani, 122
bronchialis, 122
Trichocephalus dispar, 122
Spiroptera hominis, 123
Strongylus gigas, 125
Ascaris lumbncoides, 125
vermicularis, 125

tabular view of Entozoa hominis, 126
.anatomy of the Entozoa, 126
tegumentary system, 126
epidermic processes or spines, 127

Entozoa (continued) .

muscular system, 127

nervous system, 129

digestive organs, 131

respiratory organs, 133

excretory glands, 136

organs of generation, 137
Erectile tissue, 144
Excretion, 147

I. Necessity of excretion, 148

II. Producis to be held excretions, 149
excretions from the lungs, 149

skin, 149
bowels, 149
kidneys — urine, 149

excrementitious and recfementitious secretions,
150

III. Effects of the suppression of secretions on the

animal economy, 150

IV. Manner in which excretions are effected, 150

V. Matters of excretion are separated from ihe blood

rather than formed at the parts where they ap-
pear, 1 5 1

VI. Original source of the matters thrown out by ex-

cretion, 152

Extremity (in human anatomy), 154
superior extremity, 154
clavicle, 154

structure, 156
development, 156
scapula, 156

structure, 159
development, 159
humerus, 159
structure, 161
development, 16 1
fore-arm :
ulna, 162

structure, 163
radius, 163

structure, 164

development of radius and ulna, 164
hand, 165

inferior extremity, 165
femur, 165

structure, 16?
development, 167
patella, 168

structure and development, 168
leg:
tibia, 168

structure, 170
fibula, 170

structure, 171

development of the bones of the leg, 171
abnormal conditions of the bones of the extremi-
ties, 171
Eye:

general view, 171
sclerotic coat or membrane, 174
cornea, 175
choroid coat, 178
tapelum, 179

orbiculus s, circulus ciliaris, ciliary circle, 1HO
corpus ciliare, ciliary processes, 160
pigmentum nigrum, 180
iris, 182

membrana pupillaris, 184
retina, 135

lamina cribosa, 185
porus opticus, 186
layers or membranes, 186

foramen centrale, or foramen of Soemmerriug, 188
vitreous humour, 191
canal of Petit, 192
corona ciliaris, 193
crystalline lens, 194

capsule, 199
aqueous humour, 201
pecten s. marsupium nigrum, 203
choroid gland or muscle, 205

Face (in anatomy generally and in human anatomy), 207
I. Bones of the face, 207

superior maxillary bones, 207

maxillary sinus, 209
connexions of the maxillary bone, 209
structure, 209
development, 209
ossa intermaxillaria, 210
palate bones, 210
connexions, 211
structure and development, 211
malar bones, 211
connexions, 211
structure and development, 212
nasal bones, 212
connexions, 212
structure and development, 212
lachrymal bones, 212
connexions, 212
structure and development, 212
inferior turbinated or spongy bones, gl3

ANALYTICAL INDEX.

1009

connexion?, -213

structure and development, -213
vomer, 213

connexions, 213

structure and development, '213
lower jaw bone, 213

structure, 213

connexions and »»ses, 2)5

development, 215
of the face in general. Dimensions, 215

mechanism of the face, 217

development of the face, 218

articulations of the face, 219

abnormal conditions of the bones of the face,
819

II. Muscles of the face, 22O
orbicularis palpebrarum, 221

relations, 221

action, 221

corrugatoi supercilii, 800
levator palpebrae superioris, -2-22

relations and action, 022
muscles of the nasal region :
pyramidalis, 222
levator labii superioris alzeque nasi, 222

relations and action, 222
triangularis nasi, 223

relations and action, 223
depressor alac nasi (myrtiformis), 223

relations, 223
dilator alae nasi, 223
muscles of the labial region .
oibicularis, 923

relations, 223

actions, 2-24
naso- labial is, 224
levator labii superioris, 224

relations and action, 224
zygomaticus minor, 224

relations and action, 224
zygomaticus major, 224

relations and action, 224
levator anguli oris, 224

relations and action, 224
depressor anguli oris (triangularis oris), 223

relations, action, 225
depressor labii inferioris (quadratus menti), 225

relations and action, 225
levator menti (houppe du mentou), «25

action, 225
buccinator, 225

relations and action, 226
platysma myoides, 2i6
general review of the muscles of the face, 227

III. Integuments of the face, 227
IV. Vessels of the face, 227

V. Nerves of the face, 228
VI. Abnormal conditions of the soft parts of the face,

228
Fascia, 229

1 . Cellular fasciae, 229

2. Aponeuroses, or aponeurotic fasciae, 231
Fat, 231

varieties of fat :
lard, 232
human fat, 23-2
fat of beef, 233
neat's foot oil, 233
goat's fat, 233
mutton fat, 233
whale or train oil, 233
spermaceti oil, 233
phocenine, 234
fat of birds, 234
fat of insects, 235
adipocere, 235
Femoral artei-y, 235

course and relations generally, 235
femoral canal and femoral sheath, 237
particular course and relations, 237
in its superior portion, 237
in its second or middle portion, 242
in its inferior portion, 242
varieties, 243

branches of the femoral artery, 243
superficial epigastric, 243

external pudic, 244
anterior iliac, 344
profunda femoris, 245

branches of the profunda, 246
external circumflex, 246
internal circumflex, 247
first perforating artery, 248
second peiforating artery, 248
third perforating artery, 248
termination of the profunda, 249
anastomotica maena, or superficial supe-
rior internal articular, 249

other branches, and considerations on the
collateral circulation of the thigh, 249
VOL. II.

Femoral artery (continued) .

anastomoses of the branches of the femoral ar-
tery, 25O
effects of obstructions at different points in the

course of the artery, 251
operative relations of the femoral artery, 252
Fihrine, 957
Fibro-cartilage, 290

morbid conditions of, 262
Fibrous tissue, 263

white fibrous organs, <263
yellow elastic fibrous organs, 963

I. White fibrous organs, 263

bloodvessels, -263
absorbents, 263
nerves, 263

chemical properties, 263
physical properties, 263
periosteum, 264
fasciae, 264

tendinous sheaths, 264
fibrous coverings, 264
ligaments, 264
tendons, 265

II. Yellow elastic fibrous organs (tela elastica), 985
organization and properties, 265

morbid anatomy of the fibrous tissues :
inflammation, 266

cartilaginous transformation and ossification,
266

fungus, 266
osteo-sarcoma, 267
Fibular artery, (artcria peroncca,) 267
branches -.

anterior peionceal, 257
posterior peronceal, 267

Fifth pair of nerves, trigeminal or trifacial nerve, 268
general structure and encephalic connexions, 268
external or extracephalic portion of the nerve, 278
first or ophthalmic division, 279
its branches :

recurrent branch of the first division, 279
frontal nerve, 279
nasal nerve, 281
lachrymal, 282
second division of the fifth or superior maxillary

nerve, 283
its branches :

temporo-malar, 284
spheno-palaline, 284
spheno-palatine ganglion, or ganglion of Mecfcel,

posterior-superior dental, 289
anterior-superior dental, 289
facial branches, 289

third division of the fifth or inferior maxillary nerve,2QO
its branches :

the masseteric, 291
the deep temporals,*29l
the buccal, 291
the pterygoid, 291

otic, or auricular ganglion of Arnold, 292 v
the superficial temporals, 293
the inferior maxillary or dental, 294
the lingual, 295

chorda tympani, 295
submaxillary ganglion, 297
ganglion of the fifth nerve, ganglion semilunare Gas-

serii, 293

vital properties of the fifth pair of nerves, 299
sensibility, 299

influence upon sensation and volition, 299
Bell's experiments, 299
Magendie's experiments, 300
Mayo's experiments, 300
relation to the special senses, 305
smell, 305
vision, 307
hearing, 309

influence upon the nutrition of the parts to which
it is distributed, 3O9

progression, 315
influence of disease on the functions of the nerve,

316

Fatus (normal anatomy), subvoce Ovum
Foetus (abnormal anatomy), 316
atrophy, 3 IB
hernia?, 319

hernia cerebri, encephalocele, 320
spina bifida, 321
cranial tumours, 323
injuries of the cranial bones, 323
fractures of the long bones, 324
mutilations, separation of parts already formed,

324

convulsive affections, 329

effects of mental impressions on the mother, 33O
effects of inflammation, organic lesions, &c. 33O
in the stomach and bowels, 331
liver, 331
lungs, 331

3 u

1010

ANALYTICAL INDEX.

Fatus (continued; .

pleuritis, 332
purulent effusions, 332
dropsical effusions, 33'i
induration of the cellular tissue, 332
cutaneous affections, 3'33
affections of the heart and pericardium, 334
pericarditis, 334
thymus, 334
thyroid gland, 335

abnormal conditions of the foetal bladder, 335
urinary deposits, 336
premature development of teeth, 336
intestinal worms, 336
imperforate anus, 336
rickets, 337
jaundice, 337
cirronosis, 337

accidental morbid tissues, 337
Foot, bones of the, 338
tarsus, 339
astragalus, 339
os calcis, 339
os cuboides, 340
os scaphoides, 340
ossa cuneiformia, 340
structure of the tarsal bones, 941
development, 341
metatarsus, 341

structure and development of its bones, 342
toes : their phalanges, &c. 342
joints of the tarsus, 342

anterior astragalo-calcanien articulation, 34 i
cuneo-scaphoid articulation, 343
cuboido-cuneen articulation, 343
articulation of the two rows of tarsal bones to each

other, 343

astragalo-scaphoid articulation, 343
calcaneo-cuboid articulation, 343
motions of the tarsal joints, 344
tarso-metatarsal aniculations, 344
metatarsal articulations, 345
metatarso-phalangeal articulations, 345
articulations of the toes, 345
motions of the metatarsal joints, 345

metatarso-phalangeal joints, .3-1 :>
phalangeal joints, 345
general mechanism and endowments of the foot,

arches, &c. 346

Foot, abnormal conditions of the, 347
dislocations, 347

congenital displacements of the bones, 347
distortions, 348
varus, 348
valgus, 348

equinus, 349
it-foot, 350
Foot, regions of the, 351
dorsum, 351

integuments and subcutaneous cellular tissue,

veins, &c. 351
fascia and aponeurosis, 352
region of the toes, 353
plantar region, 353

proper plantar region, 353
fascia plantaris, 354
deep-seated parts, 354
plantar region of the toes, 355
practical inferences, 355
Foot, muscles of the, 35?
of the dorsum :

extensor brevis digitorum, 35?
interossei externi s. dorsales, 35b
of the plantar region :
abductor pollicis, 358
flexor brevis pollicis, 358
adductor pollicis, 358
abductor minimi digiti, 353
flexor brevis minimi digiti, 358
flexor brevis digitorum s. perforatus, 358
flexor digitorum accessorius s. massa carnca Jacobi

Sylvii, 358
Uimbric-ales, 353

interossei interni s. plantares, 358
transversalis pedis, 358
classification of the muscles of the foot according to

their effects, 359
Fore-arm, (surgical anatomy,) 361

integuments, and parts immediately subjacent, 361
aponeurosis, 362
vessels, 363

fracture of the fore-arm, 364
Fore-arm, muscles of the, 365
in the anterior region, 366

supinator radii longus, 366
extensor carpi radialis longior, 3tJfi
pronator radii teres, 366
flexor carpi radialis, 366
palmaris longus, 367

flexor communis digitorum sublimi* s. perfora-
tus, 367

pes
flat-

Fore-arm, (continued) .

nexor carpi ulnaris, 367

flexor longus proprius pollicis, 366

flexor communis digitorum proi'undus s. pcrfo-

rans, 368

pronator quadratus, 368
in the posterior region, 363
anconeus, 368
extensor carpi ulnaris, 869
extensor communis digitorum, 369
extensor carpi radialis brevior, 369
supinator radii brevis, 369
extensor ossis metacarpi pollicis, 369
extensor primi internodii pollicis, 370
extensor secundi internodii pollicis, 370
indicator s. extensor proprius primi digiti

man us, 370

Fourth pair of nerves, 370
Ganglion, 37 1

organization, 372

reddish grey matter, 372
fibres, 374

arrangement ot the fibres in ganglia, 374
nature of t he fibres connected with ganglin, 3 1 -
coverings, 376
bloodvessels, 376
chemical composition, 376
Gasteropoda, 377

characters of the class, 377
division into orders, 377
tc-gumentary system, 379
growth of shell, 380
operculum, 384
organs of digestion, 384
mouth, 384
alimentary canal, 384
accessory glands, 388
salivary glands, 388
biliary system, 388
organs of respiration, S8<)
organs of circulation, 3(XJ
nervous system, 392

common sensation, 991
touch, taste, smell, 394
vision, 895
generative system, 396

ova, 401

reproduction of lost parts, 402
muscular integument, 402
body, 402

retractile muscles, 403
foot, 403

particular secretions, 404
Gelatin, 404
Generation, (in human and comparative anatomy,) organs

and means of, 406
fissiparous generation, 407
gemmiparous generation, 407
oviparous generation, 40"

I. Division. — Animals in which ovigerous organs

only have been distinctly recognized, 409
II. Division. — Animals provided with ovigerous
organs combined with an additional secreting
structure, probably subservient to the fertili-
zation of the ova, 410

III. Division. — Ovigerous and impregnating or-
gans co-existent, but the cooperation of two
individuals necessary for mutual impregna-
tion, 411

IV. Division. — Sexes distinct, i. c. ovigerous and
impregnating organs placed in separate indi-
viduals, 412

Insects, 413
Arachnida, 417
Crustacea, 417
Mollusca, 417
Vertebrate ovipara, 418
Fishes, 418
Reptiles, 419
Birds, 421
Mammalia, 421
testes, 422
prostate, 422
Cowper's glands, 42-2
accessory vesicles, 423
penis, structure of, 423
Generation, (in physiology,) 494

1. Function of reproduction generally considered, 4-15
introductory remarks, 426
theories of generation, 127
spontaneous generation of animals, 429
II. Sketch of the principal forms of the reproductive

function in different animal?, 432
1. Non-sexual reproduction, 432
fissiparous generation, 43*2
gemmiparous generation, 433
reproduction by separated buds 01 sporulcs,

:. Sexual reproduction, 131
nature of the ovum, 43 1
hermaphrodite generation, '• •

ANALYTICAL INDEX.

1011

Generation, (continued) .

dioecious reproduction, or with distinct in-
dividuals of different sexes. Oviparous
ami viviparous generation, 435

ovoviparous generation, 435

varieties in respect to utero-gestation and
the development of the young, 438

Marsupiate generation, 436

Monotrematous generation, 437

comparison of animal and vegetable repro-
duction, 437

synoptical table of the various forms of the
reproductive process, 438

III. Reproductive function in man and the higher

animals:

l. sketch of this function in man, 438
organs of reproduction, 438
puberty, 439

structural ditferences of the sexes, 439
menstruation, 439
periodical heat in animals, 441
age at which puberty occurs, 441
period during which the generative function

is exercised, 442
effects of castration, 443
sexual feeling, 443

relation of reproduction to the brain, 444
distinction of species. Mules, 444
functions of the external organs of repro-
duction, 445
erection, 445

IV. Changes consequent on fruitful sexual union :
i . As regards the female. Conception, 447

approximation of thefimbriated extremities
of the Fallopian tubes to the ovary, 447

changes in the ovaries: bursting of the
Graafian vesicles, -443

formation of the corpus luteum, 449

descent of the ovum. Its structure and
changes during its passage, 451

time at which it arrives in the uterus, 453

changes in the uterus after conception, 454

irregularities in the descent of the ovum,
453

circumstances influencing liability to con-
ception, 456

signs of recent conception in women, 457
•'.'. As regards the male, 457

properties of the seminal fluid, 457
chemical properties, 458
spermatic animalcules, 459
table of their sizes in different animals,
46O

circumstances upon which the fecundating
property of the seminal fluid depends, 461

difference between the fecundated and utite-
cundated ovum, 462

is material contact of the semen and ovum
necessary ? 462

external and artificial fecundation, 462

course of the seminal fluid within the female
organs, 464

nature of the fecundating principle. Hypo-
thesis of an aura, &c. 466

general conclusions respecting fecundation,

467
V. Miscellaneous topics relating to the preceding

history of generation, 468

1. superfcetation, 469

2. influence exerted by parents on the qualities of

their offspring, 470

3. number of children and relative proportion of

the male and female sexes, 478
table of the proportion of males to females

born in different countries, 478
Cland, 480

divisions and kinds of glands, 481
situations, 481
organization, 481

minute structure, 481

excretory ducts, 486

structure of the secreting canals and excretory

ducts, 487
bloodvessels, 487

arrangement of their minute subdivisions, 488
lymphatics, 489
nerves, 4SQ

interstitial cellular tissue, 489
investing membrane, 4S9

general conclusions regarding the minute struc-
ture of glands, 490"

hypotheses on this subject, 490
development of glands, 493
Glosso-phuryngeal nerve, 4<J->

origin and course, ganglion jugulare, ramus tympa-

nicus or nerve of Jacobson, &c. 492
digastric and stylo-hyoid branch, 496
carotid branches, 496
pharynpeal branches, 496
lingual branches, 497
tonsillitic branches, 497
physiology of this nerve, 497

Glutacal Region, (\n surgical anatomy,) 500

Groin, Kcyion of the, (in surgical anatomy,) 503

Haematosine, 5O3

Hair. Vide Tcgumentary System, M)5

Hand, Bones of the, (human anatomy,; 6O5

I. Carpus, 505

os naviculare, 605
os lunare, 505
os cuneiforme, 605
os pisiforme, 505
os trapezium, 506
os trapezoides, 506
os magnum, 5O6
os unciforme, 506

structure and development of the bones of carpus,
506

II. Metacarpus :

first, second, third, fourth, and fifth metacarpal

bones, 507
structure and development of the metacarpus,

507

III. Fingers, 50?

metacarpal, middle, and ungual phalanges, 507
structure and development, 5O7
joints of the hand :

joints of the carpus, 508

articulation of the two rows of carpal bones to
each other, 508

motions of the carpal articulations, 503

articulation of the pisiform bone, 5OS
carpo-metacarpal joints, 5O9

motions of the carpo-metacarpal joints, 5O9
joints of the fingers :

metacarpo-phalangeal joints, 5 10

phalangeal joints, 51O

motions of the joints of the fingers, 5k)
Hand, Abnormal Conditions of the, 510

I. As results of accidents, 510

luxations and fractures, 510

luxation of the bones of the carpus, 510

luxation of the bones of the metacaipus, 5U

luxation of the metacarpal bone of the thumb,

511
luxation of the phalanges of the fingers, 511

first phalanx of the thumb from

the metacarpal bone, 511
anatomical characters of this accident, 512
luxation of the second and third phalanges, 514

II. Diseased conditions :
spina ventosa, case of, 514
strumous osteitis, 516
malignant tumours, 516

abnormal conditions of the fingers, the result of
accidents, and morbid affections of one or
more of their constituent structures, 517

contraction of the fingers from disease of

the pal mar fascia, 517
anchylosis of the joints of the phalange?,
518

III. Congenital malformations of the hand, 519
Hand, Muscles of the, (human anatomy,) 519

I . M uscles of the palm :

a. muscles of the external palmar region, 519
abductor pollicis, 519

relations, 519
flexor ossis metacarpi s. opponens pollicis, 519

relations, 530
flexor brevis pollicis, 52O

relations, 520
adductor pollicis, 500

relations, 520

b. muscles of the internal palmar region, 52O
palmaris brevis, 52O

relations, 520
abductor minimi digiti, 580

relations, use, 520
flexor brevis minimi digiti, 521

relations, 521

adductor ossis metacarni s. opponens minimi
digiti, 521

relations, 521

c. muscles of the middle palmar region, 501

lumbricales, 521

relations and uses, 5-JM
interossei intt-rni ditmoruin, 521

relations, use, 521

II. Muscles of the dorsum :

interossei exterui, 591
relations, uses, 522
motions of the hand and its pan
Hand, Regions of the, (surgical anatomy), 523
I. Palmar region, 523
skin, 524

subcutaneous cellular tissue and nerves, 524
aponeurosis, 524

anterior annular ligament, 524
palmar fascia, 625
vessels and nerves :
nlnar artery, 525
radial artery, 526
veins, lymphatics, nerves, 5QC
median nerve, 557

1012

ANALYTICAL INDEX.

Hand, Regions of the, (continued).
ulnar nerve, .w?
muscles and tendons, 527
II. Dorsal region, 527
skin, 528

subcutaneous layer and veins, &26
aponeurosis, 528
nerves, 528

tendons and muscles, 528
arteries, 529
remarks on amputations of different members of

the hand, 529
Hearing,, Organ of. The ear, 529

I. The ear-bulb or fundamental organ of hearing, 529
I. osseous labyrinth, 529
vestibule, 530
semicircular canals, 530
cochlea, i31

canalis spiralis, 531

axis, modiolus, columella or central pil-
lar, 531
lamina spiralis, spiral lamina, and scalae,

532

the aqueducts, 532
membrane lining the labyrinthic cavity,

of the cochlea in the recent state, 533
farther observations on the aqueducts, 536
of the liquid of the labyrinthic cavity, pe-

rilymph, or liquid of Cotugno, 536
2. membranous labyrinth, 536

common sinus, membranous ampullae, and

membranous semicircular tubes, 537
saccule, sacculus rotundus, 538
liquid of the membranous labyrinth, endo-

lymph or vitreous humour of the ear, 538
of the masses of calcareous matter contained
within the membranous labyrinth, otolithi
andotoconia, 539
auditory or acoustic nerve and its divisions,

539
bloodvessels of the labyrinth, 512

arteria cochleae and arteria vestibuli, 542
II. Accessory parts of the apparatus of hearing, 543
I. Middle ear or tympanum and its appendages :
cavity of the tympanum, 543

promontory, fenestra rotunda, and fenes-

tra ovalis, 543
eminentia papillaris s. protuberantia py-

ramidalis, 544
cochleariform process, 544
osseous portion of the auditory passage, 544

tympanic ring, 544
membrane of the tympanum, 545

structure of the proper membrane, 545
hiatus Rivinianus, 546
the ossicles or small bones of the ear, 546
malleus or hammer bone, 546
incus or anvil-bone, 546
stapes or stirrup-bone, 547
position, connexions, and articulations of

the small bones of the ear, 547
muscles of the small bones, 548

internus mallei s. tensor tympani, 548
stapedius, muscle of the stapes, 549
lining membrane of the cavity of the tym-
panum, 5-19

the Eustachian tube, 549
osseous part, 549

cartilaginous and membranous por-
tion, 550

2. The external ear, including the auditory pas-
sage, 5M)

A. The auricle, auricula s. pinna, 550

helix, 550
antihelix, 551
antitragus, 5M
tragus, 551
ligaments of the ear:

anterior ligament and posterior ligament,

551
muscles of the ear :

muscles which move the ear as a whole, or
extrinsic muscles :

elevator auris, attollens auriculam,

551

retractor muscles, retrahentes auri-
culam, 552

anterior muscle, attrahens auricu-
lam, 552

intrinsic muscles of the ear:
helicis major, 552
helicis minor, 552
tragicus, 552
antitragicus, 552
transversus auriculae, 552

B. The external auditory passage, meatus audito-

rius externus, 552

the cartilaginous and membranous por-
tion, 552

inrisurae Santorinianae, 553
ceruminous (elands, 553

Hearing, Organ of, (continued).

nerves of the accessory parts of the apparatus

of hearing, 554
nerves of the tympanum, 554

nervus petrosus superficialis, 554
intumescentia gangliformis nervi fd-

cialis, 554

chorda tympani, 554
ramus auricularis nervi vagi, 554
nervous anastomosis in the tym-
panum, 554
nervus tympanicus, 554
nerves of the auricle and auditory pas-
sage, 555

arteries of the external ear and tympanum,
556

III. I. development and abnormal conditions of the

organ of hearing, 557

A. of the ear-bulb, 557

B. of the tympanum and its contents : —

cavity of the tympanum, 559
small bones of the tympanum, 560

C. of the external ear, 561

IV. parallel between the ear and the eye, 562
Hearing, (in physiology,) 564

preliminary observations on sound, 565
pitch, intensity, and quality in musical sounds, 566
reflexion of sound, 565

part performed by each portion of the auditory appa-
ratus in the function of hearing : —

I. the internal ear, 567

vestibule, the essential part, 567
office of the otolithes, 567
function of the cochlea, 568
function of the semicircular canals and sinus
commune, 569

II. The accessory parts of the organ, 571

the auricle, 571

the tympanum and its contents, 572
Eustachian tube, 576
functions of the nerves, 576
Heart, (in anatomy,) 577
Human heart (normal anatomy) :
position, 578

form and external surface, 578
right auricle, 579

external surface, 579
internal surface, 579

tuberculum Loweri, 580
fossa ovalis, vestigium foraminis ovalis, 580
annulus s. isthmus Vieussenii, 5HO
remains of the Eustachian valve, 580
valvula Thebesii, 580
foraminaThebesii, 580
musculi pectinati, 580
auriculo-ventiicular opening, 580
right ventricle, 580

external surface, 580
internal surface, 580

columnar carneae, 580
musculi papillares, 581
valvula tricuspis s. triglochis, 581
chordaj tendineae, 581
semilunar valves, 581
corpus Arantii, 513
left auricle :

external surface, 582
internal surface, 582
left ventricle:

external surface, 582
internal surface, 582

bicuspid or mitral valve, 583
semilunar valves, 584
sinuses of Valsalva, 584
septum of the ventricles, 584

thickness of the walls of the several cavities of the
heart, 585

measurements, 586
relative capacities of the several cavities, 585

measurements, 586

relative dimensions of the auriculo-ventricular ori-
fices, 587

circumference of the aortic and pulmonary orifices,
587

measurements, 587
size and weight of the heart, 587
structure of the heart, 587
tendinous texture, 587

auriculo-ventricular tendinous rings, 587
arterial tendinous rings, 587
tendinous structure of the auriculo-ventri-
cular valves, 589
tendinous structure in the arterial valves,

589
attachment of the middle coat of the arteries

to the arterial tendinous rings, 589
muscular tissue, 590

of the ventricles, 590
of the auricles, 593
inner membrane of the heart, 594
nerves of the heart, 595

middle cardiuc nerve, 595

ANALYTICAL INDEX.

1013

H*man Heart, (continued.)

interior cardiac ncnre, 595

left catdiac nerve, 593

cardiac plexus, 596
bloodvessels of the heart, 596

great coronary vein, 596

smaller posterior coronary vein, 597
anterior coronary veins, 597

vense minimae, or veins of Thebesius, 597

sinus of the coronary vein, 597
sympathies of the heart, 597
pericardium, 597

uses of the pericardium, 59P

relative position of the vessels within the peri-
cardium, 598
peculiarities of the fatal heart, 599

value of the foramen ovale, 599

Eustachian valve, 599
Physiology of the heart :

mode of action of the valves, 600
movements of the heart, 602

systole and diastole of the auricles, 602
ventricles, 60S
impulse of the heart, 604
most irritable parts of the heart, 6O7
duration of contractile power after death, 6O8
frequency of the heart's action, 609

number of pulsations in different animals, 6O9
cause of motion of the heart, 610
upon what does the peculiar irritability of the

heart depend ? 612
constancy of the heart's action, 613
regularity of the heart's movements, 6 13
sounds of the heart, 614

first sound, 616

second sound, 617

Heart (arrangement of the fibres of the), 619
Heart (abnormal conditions of thr), 610

I. congenital abnormal conditions :

congenital aberrations of position, ectopia cordis,

630

malformations by defect of development, 631
malformations of the valves, 633
congenital absence of the pericardium, 633
malformations by excess of development, 634
anomalous connexions of the vessels of the heart,

635

displacement or ectopia of the heart as a conse-
quence of disease, 635

II. morbid alterations of the muscular substance of
the heart:

inflammation, carditis proper, 636

suppuration, 633

ulceration, 637

induration, 637

cartilaginous and osseous transformations, 637

tubercles, 637

ecirrhus, 63?

medullary fungus, encephaloid tumours, 637

inelanosis, 638

hypertrophy :

simple, i.e. without change in the capa-
city of the cavities, 638
with dilatation or increased capacity of
the cavities, excentric hypertrophy,
active aneurism of the heart, 639

dilatation of the cavities of the heart, pas-
sive aneurism, 6-10

dilatation of the orifices of the heart, 640

aneurism of the heart, 640

atrophy of the heart, 642

morbid deposit of fat on the heart, fatty de-
generation, 649

rupture of the heart, 643
morbid states of the membranes of the heart : —

morbid states of the pericardium, 643

white spot on the heart, 644

tubercular formations, 645

cysts, 645

hydrops pericardii or hydropericardium, 645

pneumopericaidium, 645

morbid states of the endocardium, 645

chronic valvular diseases, 646

dilatation of the valves, 647

atrophy of the valves, 647

entozoa in the heart, 647

states of the blood in the heart after death,

648
Heat, animal, 648

temperature of the human body, 649
of the mammalia, 649
of birds, 649
of reptiles, 649
of fishes, 649
of insects, 650
of Crustacea, 650
of mollusca, 650
general conditions of organization in relation with

the production of a greater or less degree of

heat, 750
temperature of different parts of the body, 654

Heal, animal, (continued.)

relations between the temperature of Internal

parts, 654
relations between the temperature of external

parts, 655

difference of temperature according to depth, 656
influence of external temperature generally, 658
variations in temperature independently of external

temperature, 658
influence of the natural temperature of the air on

that of the body, 658

influence of different media upon temperature, 659
effects of external temperature upon aa isolated part

of the body, 660
effects of partial heating, 660

effects of excessively high or excessively low ex
ternal temperature upon the temperature of
the body, 660
influence of evaporation, 661

relations of the bulk of the body to animal heat, 862

relations of age to animal heat, 662

differences of constitution in relation to the pro-
duction of heat among animals, 667

influence of the seasons on the production of animal

heat, 668

differences according to the nature of the climate,
670

influence of sleep on the production of heat, 670

phenomena presented by hybernating animals
with regard to the production of heat, 671

of the system upon which the external temperature
acts primarily and principally, 673

influence of temperature on the vitality of cold-
blooded animals, 673

influence of temperature on the vitality of warm-
blooded animals and of man in the states of
health and disease, 674

effects of various other causes of modification in ex-
ternal agents, 68O

confirmation of the general results, 683

of the physical cause of animal heat, 683
Ikrma/tluroditism, or Hermaphrodism, 684

classification of hermaphroditic malformations, 665

I. spurious hermaphroditism : —

A. in the female, 685

1. abnormal development or magnitude of

the clitoris, 686

2. from prolapsus of the uterus, 690

B. in the male, 690

1. extroversion of the urinary bladder, 691
«. adhesion of the inferior surface of the
penis to the scrotum, 691

3. fissure of the inferior part of the urethra,

perinaeum, &c. 691

II. true hermaphroditism, 695

A. lateral hermaphroditism, 696

1. an ovary on the right side and a testis on

the lett, 698

2. a testicle on the left and an ovary on the

right side, 700

B. transverse hermaphroditism, 7OI

1. transverse hermaphrodilism with external

sexual organs of the female type, 701

2. transverse hermaphroditism with the ex-

ternal sexual organs of the male type, 704

C. double or vertical hermaphroditism, 706

1 . male vesicular seminales, &c. superadded to

organs of the female sexual type, 707

2. imperfect female uterus, &c. superadded to

a sexual organization essentially male in
its type, 707
S, Coexistence of female ovaries and male

testicles, 711

two testicles and one ovary, 712
two testicles and two ovaries, 71^

III. hermaphrodotism as manifested in the general

conformation of the body and in the se-
condary sexual characters, 7'4
general summary with regard to the nature of
hermaphroditic malformations, 722

1. of the varieties of spurious hermaphro-

ditism, 722

2. nature of true hermaphroditic malform-

ations, 723

anatomical degree of sexual duplicity in her-
maphroditism, 728

1. fallacies in judging of the addition of male

seminal ducts to a female type of sexual
organs, 729

2. fallacies in the supposed co-existence of A

female uterus with testicles and other
organs of a male sexual type, 730

3. fallacies in a supposed co-exittence of

testicles and ovaries, 731
physiological degree of sexual perfection in her-

* mapnrodites, 732

causes of hermaphroditic malformations, 733
hennaphroditism in double monsters, 736
Hernia, (morbid anatomy,) 738

circumstances under which protrusions of the ab-
dominal viscera take place, varieiies, &c. 738

ANALYTICAL INDEX.

Ilimn, (tx,ntbmcd.)

inguinal hernia, 750

-by direct descent, 75f>
crural or femoral hernia, 7 J6
umbilical hernia, 7<51
Hibernation, 7<>»

onler of consideration of the effects of hibernation,
766

I. ot sleep, 766

I 1 . of the sleep of hibernating animals, 766

III. of perfect hibernation, 768

state of the several functions in hibernation : —
sanguification, 768
respiration, 769

comparative temperature of hibernating
animals with that of theatmpsphere,77<)
circulation, 771
defecation, 772
nervous system, 772

irritability, 772

motility of muscular fibre, 773

IV. of reviviscence, 774

V. of torpor from cold, 775

Hip-joint, anatomy of the, (human anatomy,) 776
the bones, 776

acetabulum, ?7^

head of the femur, 777

cartilage of (he acetabulum, 777

fibro-cartilage of ditto, 777

ligaments, 777

round ligament, 778
capsular ligament, 778

synovial membrane, 779

arteries, 779

nerves, 779

motions, 779

t, abnormal conditions of the, 780
Sect. 1. congenital malformations of the hip-joint :

original luxation, 780

anatomical characters of the affection, 782

history of a case of congenital malformation of
the left hip-joint, with the anatomical ex-
amination of the articulation, 784

history of a second case, 786
Sect. II. disease:

inflammation of the synovial membrane and
other structures, 787
synovitis coxae, with periostitis, 788

cartilages, inflammation and destruction of the,
7K8

bones, strumous osteitis, morbus coxae, scrofulous
affection of the hip-joint, 789

acute arthritis coxa?, 790

anatomical characters, 792

chronic strumous arthritis coxae, 793
anatomical characters, 794

chronic rheumatic arthritis coxae, chronic rheu-
matism, 798

anatomical characters, 801
Sect. III. accidents:

I . fractures :

fracture of thefundus of the acetabulum, 802
fracture of the brim of the acetabulum, 803
fracture of the superior extremity of the femur,
8O4

A. intra-capsular fracture of the neck of the

femur, 804

B. extra-capsular fracture of the neck and

fracture of the superior portion of the
shaft of the femur, 805

C. fracture of the neck of the femur com-

plicated with fracture through the tro-
chanter major, 805

D. fracture of the neck of the thigh-bone,

with impaction of the superior or cotyloid
fragment into the cancellated tissue of
the upper extremity of the shaft of the

femur, 806
anatomical characters of fracture of the

neck of the thigh-bone, 807
does bony consolidation of the intra-
capsular fracture of the cervix femoris
ever occur ) 81O

II. luxations:

dislocation of the head of the femur upwards and

backwards on the dorsum of the ilium, 815
anatomical characters of this dislocation, 816
dislocation backwards or towards the ischiatic

notch, 818

anatomical characters of this dislocation, 820
dislocation upwards and inwards on the pubes, 820
anatomical characters of this luxation, 821
dislocation downwards and inwards into the
foramen ovale, 82-2
anatomical characters, 823
cases of unusual dislocations, 824
upwards and outwards, 824
downwards and backwards, 824
Hyper amia and dna'tnia, (in morbid anatomy,} 825
Hypertrofkf and /Itrojik;/, (in morbid anatomy,) 826

7/ioc Arteries, 827

primitive iliac arteries, common iliacs, R?7
internal iliac artery, 828
branches :

1. in ternal branches :

ilio-lumbar artery, 829
lateral sacral artery, 830
middle haemorrhoidal artery, R'"»>
vesical arteries, 830
umbilical artery, 830
uterine artery, 831
vaginal artery, 831

2. external branches :

obturator or thyroid artery, 831
glutaeal artery, 833
ischiatic artery, 833
internal pudic artery, 634
branches:

external haemorrhoidal arteries, KS5
perineal artery, 835
artery of the corpus cavernosum, 836
artery of the dorsum penis, 83(5
external iliac artery, 837

relations, coverings, connexions, 837
branches :

anterior or circumflex iliac artery, 842
epigastric artery, 842
methods of operation for the ligature of the external

iliac arteries, 844

comparative merits of the different methods, 84rt
operations for the ligature of the internal iliac, «4s
ligature of the primitive iliac, 849
lunominatu Arteria, (human anatomy,) 850
relations, &.c. 850
anomalies, 852
ligature, 852
Insecta, 853

Table of the arrangement of insects according to thf
system of Mr. Stephens, 856
Order I. Coleoptera, 859
Order 1 1. Dermaptera, 863
Order III. Orthoptera, 864
OrderlV. Neuroptera, 864
Older V. Trichoptera, 865
Order VI. Hymenoptera, 865
Order VII. Strepsptera, 866
Sub-class, Hanstellata :

Order VI II. Lepidoptera, 866
Order IX. Diptera, 86?
Order X. Homaloptera, 867
Order XI. Aphaniptera, 867
Order X 11. Aptera, 868
Order XIII. Hemiptera, 868
Order XIV. Homoptera, 863
Different states of existence :
the egg, 869
the larva, 869

external anatomy of the larva, 870
of the head, 872
organs of locomotion, 873
growth and changes of the larva, 874
the pupii, nymph, aurelia or chrysalis,
the imago or perfect state, 880
Dermo-skeleton, 8M

its chemical composition: chitine, 881
its thirteen segments, 882
articulations, 883

table of the parts and appendages of the head, ssr.
account of these, 885
mandibles, 888
maxilla?, 889
antennae, 890

internal parts of the head, 892
mouth, 897

development of the head, 909
thorax, 91 1

table of parts, 913
pro-thorax, 914
mcsothorax, 914
met a-t borax, 915
abdomen, 918

Organs of locomotion. — The wings, 924
articulations of the wings, 926
neuration, 926
file, 928
the legs, 931
aberrations of for"m in the organs of locomotion,

933
muscular system, 934

muscles of the larva, 935

perfect insect, 939
nervous system :
in the larva, 943
nerves of the head, 594
of the perfect insect, 948
organs of vision, 960
organ of hearing, 961
organ of touch, 96!
organ of smell, 962
development of the brain and nervous system, 96?

ANALYTICAL INDEX. 1015

l/isecta, (contm»ul.l Insecta (continued.)

organs ot nutrition : function of respiration, 987

alimentary canal and its appendages, 965 organs of generation, 990

peritoneal coat, 9Gb tegumentary appendages — hair, scales, and spines, 99S^

muscular coat, 965 Inseclicora, 994

mucous cat, 966 families, 994

alimentary canal of larva, 966 osteology, 995

appendages of the canal, 973 muscles,' 998

anal or proper uriniferous organs, 973 digestive organ?, 1000

adipose tissue, 975 teeth, IOOO

circulatory system, 976 nervous system, 1002

the heart or great dorsal vessel, 976 tegumentary system, 1004

organs of respiration, y82 organs of reproduction, 1005

I:ND OF VOL. n.

ERRATA IN VOLUME II.

Page 153, col. 1, line 13 from bottom, for articulated, read reticulated.

157, col. 2, line 20 from bottoms/or supra-spinata, read infra-spinata.
174, note, dele " and copied into Mr. Mackenzie's work on the eye."
344, line 40, for inspection, read impaction.

375, col. 2, note, for " tarsor," read " tensor."

376, col. 2, BIBLIOGRAPHY, insert Berres.

483, col. 2, line 25 from bottom, for " fluid," read " blind."

587, col. 1, line 24 from bottom, for 45$, read 31^.

587, col. 1, line 22 from bottom, for 41£, read 28|.

587, col. 1, line 20 from bottom, for 54£f, read 32§}.

587, col. 1, line 18 from bottom, for 48£, read 30^.

598, col. 2, line 11 from bottom, for "The nerves can be traced," read "The nerves

have not been traced."

608, col. 2, note,ybr " Prinella," read " Prunelle."
617, col. 1, line 32 from bottom, for " Enman," read " Erman."
849, col. 2, line 5, for pecuniary, read visceral.
In the article HEART, for Jig. 272, in references, read jig. 274, passim and vice versa.

MAUCIIANT, PRINTER, IKGRAM-COURT, rENCHURCH-Sl 11ELJ

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