least, supplementary to those organs. An-
other circumstance peculiar to birds and in-
dicative of the importance of the part that the
gland plays, is that the ducts are generally
many, two and three, and that they open by
separate orifices, and often at a considerable
distance from one another ; so that the secre-
tion may be poured forth on different and
widely separate portions of the alimentary con-
tents at one and the same time, a circum-
stance that must greatly increase and expedite
its action.
Birds, we know, seize and swallow their
food generally without any mastication, and
therefore it is not until it gets to the gizzard
* The follicles appear to contain only the granular
material, and in a minute duct I saw a number
of the nucleated cells. It is possible that they may
be a form of epithelium restricted to the terminal
ducts, by whose rupture and compression they
escaped, as the granular matter did from the fol-
licles.
that it is subjected to any mechanical force
capable of breaking it up. This, therefore,
takes place immediately before entering the
duodenum, and this throws the function of
mastication close down to the pancreas, so
that from its situation, as well as in other
respects, it should have an insalivating function.
It is always enclosed between the two arms
of the duodenal flexure (Jig. 73.); the duo-
Fig. 73.
Pancreas of the common Goose (Anas anser), show-
ing its relation to the duodenum, its duplex form,
and its ducts. (Natural size.}
denal portion of the gland being, so to speak'
alone developed. It is retained in this posi-
tion by the gastro-hepatic and gastro-colic
omenta, which sometimes simply attach it to
the border of the intestine, and sometimes
allow it to be free and floating. There is
considerable variety in its shape, but it is
always more or less elongated and slender :
sometimes it is undivided and single, in some
species deeply cleft, in others consisting of
two portions, or a double pancreas, quite dis-
tinct, each having its own duct ; sometimes
it is divided into three as in the pigeon. But
PANCREAS.
97
these arrangements are liable to considerable
variety, and perfectly independent of the in-
timate structure and function of the gland,
for in different individuals of the same species,
the arrangement of the ducts is generally the
same, however the segmentation of the gland
may vary. The gland substance is firm, much
more dense than in other orders, and not di-
vided so distinctly into lobes and lobules : it has
a finely granular and mottled appearance, in
colour pink, or a little yellowish, or brownish.
The pancreas seldom communicates with the
intestine in birds by a single canal, the ducts
are generally either two or three in number,
and each continues independent and separate
to its orifice. They do not communicate either
with one another or with the biliary canal :
although, however, exceptions are very rare,
Cuvier has met with an instance in the
stork, in which the single pancreatic and
hepatic ducts united and opened by a common
orifice.
The following table, altered from Cuvier,
shows the number of the pancreatic ducts in
several orders of birds, and their relative si-
tuation with regard to the hepatic and cystic
ducts ; it also shows the relation of these last
to one another. That canal which is first indi-
cated has its insertion the nearest to the py-
lorus ; P. stands for pancreatic, H. for hepatic ,
and C. for cystic.
We see from this table, that, as a rule, the
1. RAPTORES.
Brown Vulture
Common Eagle
Golden Eagle
Aquila Ossifraga -
Owl -
1 P.
H.
H.
1 P.
IP.
H.
P
C.
H.
2 P.
2 P.
C.
P.
2 P.
3 P.
3 P.
3 P.
H.
C.
C.
C.
Duv.
Duv. !
Cuvier.
Perrault.
Cuvier.
Night -jar - - I H.
Crow - - - I IP.
Picus (Genus) - 1 P.
Green Woodpecker 1 P.
Parrot - - 1 H.
Blue Macaw 1 H.
II. ISSESSORES.
P.
C.
2 P.
H.
C.
III. SCANSORES.
2^P.
3 P.
2 P.
3 P.
C.
1 P.
2 P.
2H.
V. GRALLATORES.
VI. NATATORES.
Grebe
Great Diver
Apterodytes
Gull -
Petrel
Swan
Duck
3 P.
C.
H.
Cuvier.
Cuvier.
Meckel.
Cuvier.
Cuvier.
Duv.
IV. RASORES.
Crax (Genus)
1 P.
2 P.
1 H.
2H.
Perrault.
Crax Globicera
1 P.
2 P.
C.
1 H.
2H.
Perrault.
Common Cock
1 P.
2 P.
3 P.
H.
C.
Duv.
Quail -.-
P.
H.
C.
Cuvier.
Pigeon
1 H.
1 P.
2 P.
2H.
Duv.
Bustard
1 P.
2 P.
H.
C.
Perrault.
Ib.
1 P.
2 P.
3 P.
H.
C.
Meckel.
Cassary
P.
C.
H.
Perrault.
Rhea Americana -
H.
P.
C.
Meckel.
Ostrich
H.
P.
Perrault.
Stork
P.
H.
C.
Cuvier.
Bittern
H.
P.
C.
Duv.
Heron
1 P.
H.
2 P.
3 P.
C.
Cuvier.
Grus pavonica
1 P.
H.
2 P.
C.
Duv.
Grus virgo
1 P.
2 P.
H.
C.
Perrault.
Curlew
H.
C.
Duv.
Ib. -
1 P.
2 P.
H.
C.
Cuvier.
Gold-headed trum-
Duv.
peter
IP.
H.
C.
Flamingo
1 P.
2 P.
3 P.
C.
H.
Cuvier.
Ib. - - -
1 P.
C.
H.
Meckel.
Parra Jacana
H.
1 P.
2 P.
Cuvier.
1 P.
2 P.
3 P.
H.
C.
Meckel.
C.
H.
P.
Duv.
1 P.
2 P.
H.
3 P.
Cuvier.
1 P.
2 P.
H.
1 C.
2C.
Meckel.
1 P.
2 P.
H.
C.
3 P.
Meckel.
1 P.
2 P.
H.
C.
Cuvier.
\ P.
2 P.
H.
C.
Duv.
98
PANCREAS.
pancreatic secretion is the first poured into
the intestines, and the cystic bile the last :
and always when there are three pancreatic
ducts, the secretion reaches the intestine early
by one of them, and the others have their
openings close to the bile ducts, either before
or between them. It is not safe, however, to
draw any physiological conclusions from these
relative positions, even supposing them to be
constant ; for the ducts are so close to one
another, that the mixture of the fluids must
take place immediately, and their action on
the food be simultaneous. In one instance,
however, this is not the case ; in the ostrich
the bile duct opens close to the pylorus, while
the pancreatic is three feet removed from it ;
this is the greatest separation of the two ducts
of any with which I am acquainted in the
animal kingdom. It would present, if ostriches
were commoner birds, great facilities for ex-
periment, and implies an action in both the
secretions entirely independent and auto-
cratic.
Mammalia. The chief differences between
the pancreas in other mammalia and man re-
late merely to its colour, its consistence, its
more or less marked division into lobes, its
form, its volume, its union into a single mass,
or its separation into two distinct parts, lastly,
its position and relations with different por-
tions of the peritoneum. Its form is generally
more or less that of a narrow band, divisible
into two portions ; one, the duodenal, following
the curvature of the duodenum, and placed
vertically or obliquely; the other, gastro-
splenic, extending transversely, and therefore
opposite the other, from the duodenum to the
spleen, against which it always abuts; the latter
is always developed, the former is often incon-
siderable or suppressed, and must be con-
sidered merely as an accessory portion. The
various forms and arrangements of the pancreas
do not appear to have anything to do with it?
essential structure or function, or the parti-
cular exigencies of the animal ; they seem to
depend entirely on the relations of the neigh-
bouring organs, the presence or absence of an
abundant mesentery, the free movement of the
duodenum, &c., and to be influenced by con-
siderations of package.
In the Ourang the form very much resem-
bles that of man ; in most other Quadrumaiia
Fig. 74.
Pancreas of the Rat (natural size), shown by throwing up the duodenum, together with its proper mesentery,
and the free process of peritoneum ex Ending thence to the left, in which the gland ramifies. Its arborescent
form and great extent are well shotvn.
PANCREAS.
99
it is irregular. In the Carnivora it is always
large in proportion to the size of the animal*,
both the duodenal and gastro-splenic portions
being highly developed. In the ox, from the
distinctness of the two portions, the organ has
a bilobed appearance. In the horse, from the
gastro-splenic portion being double, it has a
trilobed form. But the most remarkable pan-
creas is that of the Rodents; it is spread out in
an arborescent manner, in an extensive mesen-
tery that imparts free movement to the long
duodenum, and extends towards the left in a
sort of omentum, which underlays the stomach.
(Fig. 74.) Confined thus between the two
layers of a mesentery, the ramified lobes of the
pancreas lie all in one plane. Although their
distribution is somewhat irregular, they more
or less radiate in their general direction from
the point at which the duct enters the intestine,
which in the rabbit is nine inches or a foot
from the pylorus. That part of it which occu-
pies the duodenal mesentery must be consi-
dered the representative of the duodenal por-
tion, and that spread out in the omentum
underlaying and attached to the stomach, as
the gastro-splenic. Altogether, this arbores-
cent pancreas of the Rodents is very volumi-
nous, particularly in the rat, from which the
drawing was taken.
The pancreatic duct has in Mammalia gene-
rally the same branched character as in man,
the greater and lesser branches corresponding
to the lobes and lobules ; usually there is but
one orifice, rarely more, and most commonly
it enters the intestine near the pylorus, although
sometimes a great way removed from it. In
most of the Carnivora it is, as a rule, united
with the choledoc duct : in some cases it pre-
sents at the point of its immergence into the
intestinal canal a sort of ampulla, in which the
secretions probably mingle before their entry
into the intestine. There are, however, con-
siderable varieties of insertion in the lion
two pancreatic ducts join the choledoc sepa-
rately, one near the other. But whether
the ducts enter bv a common orifice, or by
two neighbouring ones, or whether there are
one or two pancreatic ducts, has, probably, no
physiological import whatever, as it cannot
make any difference whether the secretions
are brought into contact just before or just
after entering the bowel ; and this belief of
the non-essential character of these varieties
is strengthened, or rather proved, by their oc-
currence in closely allied species of the same
genus, and even in different individuals of the
same species. Cuvier says that he has ob-
served, although very rarely, in the domestic
cat, a lateral reservoir for the pancreatic secre-
tion, analogous to the gall bladder. Its duct,
about the size of the cystic, was an inch and a
half long before it united with a trunk formed
by the union of two pancreatic ducts, a prin-
cipal and an accessory, and, together with this,
formed a common duct analogous to the ductus
communis choledochus. Tiedemann has de-
tected a similar pancreatic reservoir in the
* See the physiological portion of this article,
page li' l.
common seal. The greatest distance from the
pylorus at which the pancreatic duct enters
the intestine occurs, I believe, in the Rodents.
In the rabbit this distance amounts to a foot
or upwards; and this arrangement, by giving a
considerable length of small intestine whose
contents are not acted on by the pancreatic
secretion, has afforded special facilities for ex-
periment.
III. PHYSIOLOGY.
Anatomy always implies physiology,
structure, function ; and the mind passes from
the one to the other by a ready and almost
irresistible transit. In fact, organisation is
but the accumulation, in certain parts, of
certain material agents, the sum of whose
common action gives as its result the func-
tion of the organ, and both the nature of
the elements so accumulated, and the method
in which they are built up, are determined
by, and have sole reference to, the work
to be done. Physiology invariably stands to
anatomy, even in its ultimate and minutest
details, in the relation of final cause. Now,
there are certain anatomical conditions that
always indicate physiological importance ;
among these are volume and constancy,
constancy in existence, and constancy in
structure. In all these respects we should
be led to infer from the consideration of the
anatomy of the pancreas that it possesses
essential functions ; for it is always of con-
siderable size, has a very wide range of exist-
ence, throughout the whole of Vertebrata,
from the lowest fish to the highest mammal,
and is analogically represented in many In-
vertebrata ; and, lastly, in structure it exhibits
with very few exceptions, throughout this
wide range, a remarkable sameness.
The opinions entertained by the old ana-
tomists with regard to the office of the pan-
creas were many and various. The earliest
anatomical writers do not seem to have been
aware of its existence*; some thought that
its object was to underlay the stomach as a
cushion or pillow, and to serve for the dis-
tribution of vessels ; others, that it admitted
the chyle from the intestines ; others, that
it purified the dregs of the chyle ; others,
that it served for the spleen a purpose ana-
logous to that of the gall bladder for the liver ;
others, that by it were thrown off the gross
and used-up dregs of the blood ; others, that
the organ was formed for the reception of
the excretion of the nerves ; others, finally,
taught that the pancreatic secretion was not
only useful, but played a vital and essential
part in the organism. The first opinion,
which was of very ancient date, was held by
Vesaliusf ; but it is at once refuted by a
reference to those animals, birds and fish, for
example, in which the pancreas is frequently
remote from the stomach. The second view,
that the pancreatic duct admitted the chyle
from the intestines, is assigned to Baccius
and Folius, who both maintained that it
* Hippocrates nowhere mentions it.
f De Humani Corporis Fabrica, i. 5. cap. 4. De
Omento.
H 2
100
PANCREAS.
served for the transit of the chyle from the
intestine to the liver and spleen. Very early
investigation, however, showed the fallacy
of this view, as it proved that the fluid of
which the pancreatic duct was the channel
always passed to the intestine and never front
it. The fourth opinion is ascribed to Ves-
lingius, who says, in speaking of the pan-
creas*, Usus hujus canalis obscurus non est,
ncnn cum acrem quendam fellique non dissi-
milem succum exhibeat, palam est excreinentum
tale, per coctionem ulterior em a chylo separatum,
allici infra hunc atque in duodenum intcstinum
expurgari. This view, which is simply re-
futed by saying that the secretion obtained
from the pancreas does not in any way resemble
bile, that it is not " felli non dissimilem," was
supported by Asellius. Riolanus, and others.
De Graaf accounts for it by supposing that
the tube introduced into the duct for the
purpose of obtaining the secretion became
covered with the bile accumulated about the
common orifice of the two ducts, which it
might very well do, either on being inserted
or withdrawn, and that this, becoming mixed
with the pancreatic secretion which it had
withdrawn, gave rise to the erroneous opinion
that that secretion had a resemblance to bile.
The fourth opinion, that the pancreatic duct
was the excretory canal of the spleen, which
was maintained by Bartholini, is refuted by
the simplest anatomical considerations, and
was further disproved by De Graaf, who, to
show its fallacy, extirpated the spleen of a
dog, and, two months after the extirpation,
obtained the pancreatic secretion unaltered.
The fifth view was based on similar supposed
anatomical relations between the pancreatic
duct and spleen. It is assigned to Lindanus,
and was refuted by the same considerations
as the last. The theory that the pancreas
carried off the excretion of the nerves was
based on the old view that the nerves distilled
the animal humours and spirits. AH these
views are perhaps rather amusing than in-
teresting, and are among the curiosities of
science. They show us how much our me-
dical forefathers were disposed to take for
granted, and how disposed they were to run
alone when the shell was still on their heads.
The true doctrine that the pancreas furnished
an important secretion of its own was first
advocated by Francois de le Boe Sylvius -f-,
who first insisted on its acidity, and who at-
tached great importance to its pathological
conditions. Indeed, he made its derangements
the cause of nearly all the ills that flesh is
heir to ; in the same way that Spigelius did
his lobe of the liver. It was in consequence
of the interest which the lessons of Silvius
excited that De Graaf, his pupii, undertook
his admirable researches De Succo Pancrea-
t>co, and succeeded, in 1662, in first obtaining
the pancreatic secretion from the living ani-
mal : the most important point was thus
ascertained, and the materials supplied for
further investigation.
* Syntagma Anatom. cap. 4.
t Tlies. 37., De Usu Lienis et glandular.
With the view of obtaining the fluid, De
Graaf first put a ligature round the duo-
denum, including part of the pancreas, but
failed in obtaining the desired result, in con-
sequence, as he imagined, of the ligature
about the pancreas cutting off the supply
of blood from which the secretion was ob-
tained, and so putting a stop to it. He
then put a ligature round the duct at the
point of its immergence into the intestine,
but again failed in getting any secretion,
which he attributes to its escape by the small
ducts wounded in exposing the larger one.
His third attempt consisted in binding together
two pieces of wood, compressing the intestine
over the point of entrance of the duct so as
to close it. This time he was successful :
the duct was distended with a clear and
limpid fluid, but he could not obtain it in
sufficient quantity to subject it to any ex-
amination. With the view of obtaining sonic
notable quantity, he instituted a fourth ex-
periment by making a longitudinal incision
into the duodenum, and inserting into the
orifice of the duct the narrow mouth of a
little flask ; but again he failed, from the air
included in the flask barring the entrance of
the secretion. To obviate this, in his fifth
experiment he perforated the upper part of
the flask with a little hole, and this time he
succeeded, in the space of five hours, in get-
ting the flask more than half full. But the
secretion obtained was bitter in taste and
yellow in colour, and, attributing this to a
certain admixture of bile from the uncleansed
intestine, he improvised the following in-
genious apparatus to obviate that source
of fallacy. He took a long-necked flask,
with a hole bored in the upper part of its
belly, and around the neck of this flask he
fastened a cord furnished with rings, by
means of which it could be firmly fastened to
the intestine ; a quill of a wild duck, cut so
as to form a little slender tube, was then
fixed into the neck of the flask, and made to
fit tightly by pasted paper being rolled round
it. Into the smaller extremity of this quill
tube was fixed a plug made of some soft
wood fitting sufficiently tight not to be forced
in by the pressure of the soft parts it would
come in contact with, but sufficiently easy to
be withdrawn by a string fastened to it, and
which passed through the quill into the flask
and out of the flask through the little hole.
The object of the plug was to prevent the in-
testinal contents from blocking up the quill and
so obstructing the flow of the pancreatic secre-
tion. Then (" sublato ejulatu vicinis molesto,
duarum laryngis cartilaginum particulas ex-
scindendo," as he says of the poor dog with
great simplicity and coolness) the abdominal
cavity is laid open, an incision is made into
the duodenum, the quill, closed with the little
plug, inserted, the flask sewed to the intestine
by means of the rings, the parietes sewed up
so as to allow the protrusion of the flask,
the plug withdrawn by the string, and the flask
covered so as to prevent the entry of any
foreign matter through the little hole. To
PANCREAS.
101
obviate the escape of the secretion through
a second pancreatic duct, which, he says, he
found very common, he closed this second
orifice by an ingenious method of compres-
sion. With this apparatus he succeeded in
getting a free supply of pancreatic fluid, as
clear as spring water, but slightly viscid, and
van ing in taste, from salt to acid, rough,
acidulo-saline, or insipid. De Graaf's memoir
is well worth reading, and is, considering the
time in which it was written, and in spite of
the necessary admixture of a good deal of
mediaeval physiology, a model of sagacious
forethought and patient research. He insists
strongly on the acidity of the fluid, not only
in the dog, but in man, and affirms that he
and many others found it to possess an acid
taste in a man who had been suddenly killed,
and whose body was still warm. But it is
necessary to bear in mind his coarse and
superficial means of examination, and the bias
with which he undertook his researches from
his strong attachment to both the physio-
logical and pathological views of Sylvius.
Schuyl*, also a disciple of Sylvius, adopted
a process analogous to that of De Graaf, and
succeeded in obtaining a quantity of the
secretion, amounting to two or three ounces,
in three hours ; he pretends that what he
collected had an acid taste, and affirms, more-
over, that it coagulated milk. The researches
of Wepferf, Pechlin J, Brunner$, and Bohn j|
did not confirm the assertions of De Graaf
and Schuyl. These observers found the
pancreatic secretion turbid, whitish, not acid,
but having a taste slightly saline, like that of
lymph. Succeeding experimenters agreed no
better with regard to the qualities of this
liquid. Viridetlf said that he found it acid
in most animals, and pretended that it sen-
sibly reddened litmus. Hduermann**, on the
contrary, denied that it had this effect.
Fordyce f f found that of the dog to be co-
lourless, watery, and salt in taste, and affirmed
it to be composed of water, mucus, soda and
phosphorus. Meyer JJ has examined the pan-
creatic juice in a cat, which he found in the
vesicular reservoir which is sometimes met
with in that animal. It appeared transparent,
viscid, and had an alkaline taste ; it coloured
the mallow dye red, and red litmus paper
blue. Meyer says further that he found in it
albumen, chlorides of sodium and ammonia,
and a peculiar matter giving a violet pre-
cipitate, with chloride of tin. Lastly, Ma-
genclie found the pancreatic juice in a dog
to be yellowish, inodorous, and with a saline
taste. He adds that the liquid is alkaline,
* Tractatus pro Veteri Medicina. Leyde. 1670.
t De Cicuta Aquatica, p. 200.
j De Purgantium Medic. Facult. Leyde. 1672.
Experiment Xova circa Pancreas. " Amst. 1C83.
J| Circulus Anatomico-physiologicus. Leipsig,
De Prima Coctione, p. 266.
'* Physiologic, th. iii. p. 807.
ft Versuche Uber das Verdauungsgeschaft, Leip-
sig, 1793.
JJ Journ. compl. et Diet, du Sc. Me'd. t.iii. p. 283.
Pre'cis Ele'mentaire de Physiologie, t, ii. p. 267.
that it coagulates with heat, and that in birds
it is altogether albuminous ; at least, that, ex-
posed to heat, it coagulates like albumen.
With such various opinions as to the qua-
lities of the secretion, it is not surprising that
the views of its function should have been
discrepant, and accordingly we find that
many hypotheses, often far-fetched and extra-
vagant, were adopted to explain the part
which the pancreatic fluid played in digestion.
Some thought that it had for its destination
the separation of the chyle from the excre-
ments ; others, that it served to temper the
acridity of the bile; others, again, thought
that it diluted the chyme, or that it dissolved
that portion of the food which had not been
digested in the stomach ; that it contributed
to its assimilation, &c. Haller, after ex-
hausting himself with conjectures, can only
say, " Plura possunt esse officia liquoris non-
dum satis noti ;" and Magendie, fifty years
later, admits that it is impossible to say what