the role of the pancreatic fluid may be.
Such, then, were the opinions expressed, or
rather the ignorance confessed on this subject,
when in 1823 the Academy of Paris proposed
the function of digestion as the subject of a
prize dissertation, and two of the essays sent
in, which were considered by the Academy
worthy of honourable mention the one by
Professors Tiedemann and Gmelin, and the
other by MM. Lenret and Lassaigne threw
so much additional light on the subject, and
furnished results which so long constituted
the staple of our certain knowledge of the
function of the pancreas, and so much of
which still remains unquestioned, that they
deserve special consideration.
Lenret and Lassaigne, thinking that the
failures of recent experimenters to get any of
the secretion arose from the smallness of the
duct in the animals employed, selected the
horse, and succeeded in obtaining three ounces
in half an hour of a limpid liquid, with a slightly
salt taste, alkaline reaction, specific gravity
of 1-0026, and containing '9 per cent, of solid
matter. Sulphuric, nitric, and hydrochloric
acid slightly troubled it, and alcohol formed a
more abundant cloud, precipitated after a time
in white "flocculi ; an aqueous solution of
chlorine determined a light flocculent preci-
pitate ; infusion of gall-nuts occasioned a
yellowish deposit ; lastly, nitrate of silver and
protonitrate of mercury showed the existence
of chlorides, and oxalate of ammonia that of
lime. On treating the solid residuum with
alcohol and evaporating, it yielded a transpa-
rent viscid matter, with a salt and sharp taste,
the non-crystallizable portion of which con-
sisted of an azotised substance precipitable by
many metallic salts and solution of gall-nuts.
That portion of the residuum of the pan-
creatic juice which had been exhausted by
the alcohol was then heated with distilled
water, when this latter showed on evaporation
a certain viscosity, indicating the solution of an
animal principle in it. The result of the en-
tire qualitative analyses, the further details of
which I need not give, was as follows :
ii 3
102
PANCREAS.
Water -
Animal matter soluble in alcohol
Animal matter soluble in water
Traces of albumen
Mucus -
Free soda
Chloride of sodium
Chloride of potassium
Phosphate of lime
99-1
00*9
Oxide of iron
-J
- a trace
100-0
" Not content," say these observers, " with
this first experiment, we undertook a second
with the same success *, and the results fur-
nished by analyses were absolutely the same :
from which we infer that the pancreatic juice
possesses a perfect analogy with the saliva
both of man and the horse, these two liquids
containing absolutely the same fixed principles,
nitrogenous and saline, and almost exactly
the same quantity of water.-f- The attempts of
these authors to obtain the pancreatic secre-
tion of a dog, after the manner of De Graaf,
were all unsuccessful; ten times they tried, and
as often failed ; a few drops were all they could
procure. Their data, therefore, are all taken
from the secretion as they found it in the horse.
Tiedemann and Gmelin J obtained the pan-
creatic fluid from the dog, the sheep, and the
horse that is, from one carnivorous and two
herbivorous animals ; and their results present
the most striking discrepancies with those of
the contemporaneous experiments of Lenret
and Lassaigne. In the dog this fluid, which was
obtained abundantly, was limpid, with a faint
blueish, opalescent cast, and a mucilaginous
feeling like the white of egg diluted with water,
a slight but sensibly saline taste, the first por-
tion faintly acid, the portion last secreted
slightly alkaline, and so abundantly albumi-
nous as to be rendered semi-solid by heat
nitric acid, &c. A hundred parts of the se-
cretion contained
Solids - - 8-72
Water - - 91-28
100-00
100 parts of solid matter contained
Organic substances, osmazome with
a peculiar animal matter coloured
red by chlorine (with alkaline
acetates and chlorides) - - 44-32
Caseous substance, possibly with
another animal substance, solu-
ble in water, but not in alcohol
(with salts of soda) _ lg'44
Albumen, with a small quantity of
salts - ... 42-83
105-59
Exceeding - 5-59
* They do not say the quantity they obtained
this time.
f Loc. cit. p. 106.
| Recherches Experimentales Physiologiques et
Chimiques sur la Digestion. Jourdan's transla-
tion, p. 24. et seq.
The secretion of the sheep was acid, and,
like the other, ropy between the fingers like
white of egg, and limpid ; it was perfectly so-
lidified by heat, and contained
Solids (desiccated) 5-19
Water - - 94 81
100-00
Of these solids nearly 60 per cent, were
albumen. The secretion in the horse resem-
bled in all its reactions that of the sheep,
except that the albumen was not so abundant.
The summary conclusions at which these
authors arrive, are that the pancreatic fluid
contains
1 . In solids, in the dog 8*72, in the sheep 5
per cent.
2. The solids consist of
a. A large amount of albumen, about half
of the dry residuum.
b. Osmazome.
c. A substance reddened by chlorine,
found only in the dog.
d. A caseous substance, probably allied
to salivary matter.
e. A small amount of free acid, probably
acetic, present in all these specimens.
It is worthy of remark, that that por-
tion of the pancreatic fluid which was
secreted last was slightly alkaline :
this change probably depended on the
enfeeblement of the nervous influence
resulting from the operation.
/. The ash consisted of alkaline carbo-
nate, chloride, phosphate, and sulphate,
and carbonate and phosphate of lime.
g. The alkaline sulpho-cyanide is not
met with in the pancreatic secretion.
h. The alkali consists of a large quantity
of potash, and a very small portion of
soda salts.
If we compare the composition of the pan-
creatic secretion in the dog and the sheep
with that of the saliva, we find the following
differences :
1. The solid residue of the saliva does not
equal half that of the pancreas.
2. The saliva contains mucus and a peculiar
animal (salivary') matter. If it contains al-
buminous or caseous matter, these subtances
are, in every case, in very small quantity.
On the contrary, the pancreatic fluid contains
an abundance of albumen and caseous matter,
but not a trace of mucus, and true salivary
matter, if it exists, is in very small quantity.
3. The saliva is neutral, or contains a little
alkaline carbonate. The pancreatic secretion
contains a little free acid.
4. The saliva contains sulpho-cyanide of
potassium ; in the pancreatic fluid there is
none.
5. The other salts are nearly the same.
6. It results, therefore, that those physio-
logists who think the pancreatic secretion
identical with saliva are in error.
There is, then, an entire discrepancy be-
tween these two authorities with regard to
the pancreatic secretion its physical quali-
ties, reaction, amount of solids, chemical con-
stitution, the conclusions they infer, &c.
PANCREAS.
103
Very lately this subject has been taken up
by several able physiologists, and Bernard*,
Frcrichs -J-, and Bidder and Schmidt J, have
given to the world the results of careful and
elaborate researches both into the physical
and chemical characters of the fluid and its
physiological action. I shall describe first the
observations of these inquirers on the qualities
of the secretion, and, afterwards and sepa-
rately, their views of its physiological office.
It is very remarkable, that the differences
in the accounts given by these recent investi-
gators are vcr}- closely analogous to those ex-
isting between the results of the researches
above described. They all agree, however, as
to the invariable alkalinity of the secretion,
the absence of sulpho-cyanides, the existence
of a specific nitrogenous principle, and, in
general, to its possession of strong differen-
tial characters when compared with saliva.
According to Bernard, the pancreatic secre-
tion obtained artificially during the life of the
animal is of two very distinct kinds, which he
characterizes as normal and morbid; the for-
ner obtained when the experiment is made
under favourable circumstances, before inflam-
mation has attacked the pancreas, or which is
collected from a dog possessing a permanent
pancreatic fistula; the latter alwajs secreted
in great abundance when the symptoms of in-
flammatory reaction appear in the pancreas
and in the wound in the abdomen.
The normal secretion, which, adopting Ber-
nard's view, is of course the secretion, he de-
scribes as a colourless, limpid, viscid, ropy
fluid, without any characteristic odour, and
having a saline taste very like that of the
serum of the blood. It is constantly alkaline.
Exposed to heat, it is converted into a solid
white mass ; the coagulation is as entire and
complete as that of white of egg, the whole
becomes solid, not a drop of free liquid re-
maining. The other reagents of albumen
equally precipitate it. The alkalies produce
no precipitate, and redissolve the organic
matter when it has been previously coagulated
by heat, alcohol, or the mineral acids. But,
although exhibiting the same reactions, Ber-
nard believes that this nitrogenous principle
is essentially distinct from albumen, not only
in a physiological point of view, but in its in-
herent nature; and, as a proof of this, he
cites the fact, that when it has been coagulated
by alcohol and dried, it is easily and entirely
redissolved in water, whilst albumen, similarly
treated, is not dissolved to any appreciable
extent. <) These characteristics of the fluid,
which are given from the dog, Bernard says
obtain equally in rabbits, horses, and birds.
The n-orbid pancreatic fluid, which is alone
thrown out when the experiment is tardily or
* Arch. Gen. de MeU, 4th Ser. torn. 19. p. 6886.
f Wagner's Hanchvorterbuch der Physiol.
j Die Verdauunggeschaft und der Stoffwechsel,
Leipsig, 1852.
Bernard believes this to be the active matter
of the secretion, as it imparts to the water the pe-
culiar viscosity aud physiological properties of the
pancreatic fluid.
roughly performed, and uhich always succeeds
to the other when the experiment is happy, is
watery, without any viscosity, has a saline and
nauseous taste, is of very low specific gravity,
and gives hardly any precipitate on the appli-
cation of heat, nitric acid, &c. It is poured
out very abundantly : Bernard collected from
a dog more than half an ounce in an hour,
whereas of the normal he found 31 grains
a maximum. The normal is not transformed
into the morbid secretion suddenly, but gra-
dually, losing, as it becomes more "and more
watery, its physiological properties, of which
at last it is quite destitute. This observation
of Bernard's is very important, as showing
the facility and extent to which the fluid
may be changed, and doubtless it goes some
way to explain the discrepancies of the ac-
counts which different observers have ren-
dered, but it is not entirely sufficient for this,
as, in some hands, a watery fluid with but little
albuminous matter and of very low specific
gravity seems to have been obtained at once,
even under circumstances the most favour-
able.
Frerichs, who has made a most complete
analysis of this fluid *, and with whose ac-
count Lehiuann-{- agrees, describes it as co-
lourless, clear, very slightly tenacious, without
taste or smell, of alkaline reaction and a spe-
cific gravity as low as 1-008 to P009 ; heat,
alcohol, and acid, produce but a slight turbi-
dity; of solid constituents he found it contain
but 1*36 per cent, in the ass, and 1*62 in the
dog.
Schmidt's account is something interme-
diate between the other two; he describes the
fluid as ropy and viscid, and as being coagu-
lated by heat into a milky mass, from which
white flocculi subside, leaving above a clear,
strongly alkaline fluid. He agrees with Bernard
in the solubility by water of the precipitated
and dried albuminous matter ; he states the
specific gravity of the fluid at P03I, and the
quantity of solid constituents at 9'924 per
cent.; in one case the amount of solids reached
11*56 per cent.
The following are the quantitative analyses
of Frerichs and Schmidt :
Pancreatic juice of ass (Frerichs).
Water - ... 986'40
Solid residue - - 13'60
Fat -
Alcohol extract
Water extract
Soluble salts
Insoluble salts
026
0-15
3-09
8-90
P20
Pancreatic juice of dog (Schmidt).
Water- - - - 900'76
Solid residue - - 99-24
Organic matter
Inorganic
90-J8
8-86
* Op. cit. p. 842849.
t Physiol. Chem. (translated by Day), p. 112.
et seq.
H 4
104
PANCREAS.
The exact nature of Frerichs' water extract
Schmidt's organic matter is not deter-
mined ; it is a substance resembliny albumen or
casein, but not identical with albuminate of
soda, with casein, or with ptyalin. It coagu-
lates only imperfectly when heated (probably
from its containing an alkali), is precipitated
by acetic acid, but slowly redissolved in an
excess, especially if heated ; it is precipitated
by nitric acid and by alcohol; on the addition
of chlorine- water it separates in grayish flakes.
It is to this substance that the pancreatic fluid
owes its principal chemical and physiological
properties.
Bernard found a considerable quantity, and
Frerichs a smaller amount ('026 per cent ) of
a buffer-like fat.
The pancreatic secretion is peculiarly prone
to putrefactive change. Bernard found that
when exposed to a low temperature, it might be
kept for many days, and that by the reduction
of the temperature the viscidity was increased,
approaching a jelly-like firmness. If, on the
other hand, it was kept at a temperature of
40 to 45 centigrade (about 105 Fahr.), it
became rapidly modified, and in the lapse of a
few hours quite altered, giving out a nauseous
odour, presenting a cloudy deposit, and losing
its property of coagulation by heat. In the
heat of summer and in stormy weather, this
change takes place almost instantaneously, so
that great care is necessary in maintaining at
a low temperature both the pancreatic fluid
and the animal furnishing it, lest the alteration
should take place whilst it is still in the vessel
in which it is being collected. Frerichs found
that after exposure to the air for a few hours
it developed a distinct odour of putrefaction.
Bernard observed that the deposit that was
produced at the moment of the alteration of
the fluid, had sometimes a peculiar soft, silky
appearance, and he always found in that case,
on examining it by the microscope, a large
quantity of acicular crystals, having the cha-
racters of crystals of margarine or margaric
acid.
The secretion is not constant, but intermit-
tent, and is entirely regulated by the process
and stages of digestion ; all observers agree in
this. Bernard killed three dogs in three dif-
ferent conditions with regard to the function
of digestion one just after a meal, as diges-
tion was just commencing ; another four hours
after a meal, when digestion was at its height ;
and a third after a twenty-four hours' fast.
In the first, the tissue of the pancreas was
slightly turgid with blood, and the secretion
the most abundant, and this he has always
found to be the case ; he collected upwards of
two grammes an hour ; in the second, the
pancreas was highly turgid " gonfle de sang,
et comme erectile," and the amount secreted
less than a gramme an hour ; in the third it
was white, exsanguine, the duct empty and
collapsed, and the amount secreted in 'many
hours hardly enough to moisten the inside of
the little reservoir adapted for its reception.
The information respecting the absolute
quantitative relations of the secretion is very
defective. We have seen that Lenret and
Lassaigne obtained three ounces from the
horse in half an hour, and Bernard from the
dog thirty-one grains an hour; Frerichs col-
lected three hundred and eighty grains from
an ass in three quarters of an hour, and forty-
five from a hound in twenty-five minutes ; but
these statements, as well as 'those of Colin *,
become valueless from the fact that the ani-
mals experimented on were not weighed. The
most reliable estimate is that of Bidder and
Schmidt ; they say a dog yields a grain and a
half per hour for every two Ibs. of weight ;
therefore an adult man weighing about 140 Ibs.,
would secrete in twenty-four hours nearly five
ounces of pancreatic juice, containing 225
grains of solid residue. But it is doubtful
whether any safe data as to quantity are fur-
nished, or can be furnished, by any experi-
ments made by measuring the amount pro-
cured artificially from the living animal ; the
abnormal condition of the gland produced by
the experiment must be such, and the conse-
quent disturbance of the secretion so great, as
to throw doubt on the most careful and exact
estimates. The case in which the quantity
seems most likely to be normal is that in which
the secretion is obtained, as in some of Ber-
nard's experiments, from a permanent fistulous
opening. All observers confirm Bernard's
statement as to the exsanguine and passive
condition of the gland in animals fasting.
The natural stimulus of the secretion is,
no doubt, the digestive process going on in
neighbouring organs, producing, through the
medium of the sympathetic nervous connec-
tions, a vascular engorgement of the pancreas
and an exalted nutrition of its secreting
agents. Possibly the pressure from a dis-
tended stomach may have something to do
with it ; and there is reason to think that the
presence of food in the duodenum is both a
stimulus to the secretion and to its discharge ;
for on the application of chemical and me-
chanical stimuli to the inner surface of the
duodenum near the orifice of the duct, the
amount discharged is sensibly increased.
Possibly food of one nature in the duodenum
may be a more exciting stimulus to the se-
cretion than another. Whether this is so,
whether the amount secreted would be ex-
cited more by an animal than a vegetable
food, whether it bears the same relation to
the volume of the gland in Carnivora and
Herbivora, or whether the volume of the
gland is always a direct measure of the amount
secreted, are questions upon which, as yet,
our information is very defective. They are,
however, not unimportant questions ; for
there is every reason to believe that the
quantity secreted is always in proportion to
the exigencies of the digestive process, and
their solution might therefore throw some
light upon the function of the secretion.
There can be no doubt that muscular move-
ment and pressure facilitate the discharge of
the fluid, as most observers, from De Graaf
* Comptcs Rcndus, vol. xxxi. p. 374., and
vol. xxxii. p. 85.
PANCREAS.
105
downwards, have remarked that the act of in-
spiration, and violent respiratory or struggling
efforts, always increase the rapidity of its
flow.
The following is a tabular view of the state-
ments of different observers of the principal
characters of the pancreatic secretion :
I Ticdeinann and
Gmelin.
Lenret and
Lassaigne.
Bernard.
Frerichs.
Bidder and Schmidt.
General
Physical
Qualities.
Limpid with a blue-
white cast, like white
of egg diluted
with water, slight,
but sensibly saline
taste.
Limpid with a
slightly salt taste.
Colourless, limpid,
viscous and stringy ;
odourless ; taste sa-
line.
Colourless, clear,
<lig/itly tenacious,
without taste, or
smell.
iJ
Clear, colourless,
viscid and ropy.
Reaction.
(at first slightly
n ) acid, after
U Z} slightly alkal-
(ine.
Sheep, slightly acid
Hore, ditto.
Alkaline.
Always alkaline.
Alkaline.
Strongly alkaline.
Specific
Gravity.
1-0026
. 1 008 to 1-009
1-031
Amount
secreted.
At the rate of one
ounce per hour in
the dog.
Three ounces in
half an hour horse.
Xormal 31 grains
an hour.
Marbid. 279 ditto.
380 grains in f of
an hour ass.
45 ditto in 25 min.
-dog.
]J grain every
hour for every " Ibs.
weight. dog.
Quality of
Solids.
Dog, 8-72 per cent.
Sheep, 5-19
9 per cent.
Ass . . 1-S6
Dog . 1-62
9-924 per cent.
Amount of
Albumen,
ftc.
Rendered semi-solid
by some of the re-
agents of albumen
dg'
Perfectly solid b\
heat sheep.
Abundant consis-
tent flocculi on heat
horse.
Slightly troubled by
he reagents of albu-
nen.
Azotised principles
^oluble in alcohol and
water.
Absolutely the same
is saliva.
Entirely solid bj
heat, as white of egg:
also the strong mi-
neral acids and alco-
hol.
The dried precipi-
tate may be re-dis
solved in water.
No sulphocyanides.
Inconsiderable coa-
gulation on heating.
Slightly turbid on
adding alcohol and
nitric acid.
Butter- like fat C-026
No sulphocyanides.
Alcohol coagulates
it into a miky mass,
which deposits thick
white flakes, leaving
above a strongly al-
kaline solution.
The dried flakes
dissolve in water.
Function of the pancreatic fluid. The first
indication of the importance of the pancreatic
juice to the process of digestion has been as-
signed to Valentin. He showed that it con-
verted into sugar that portion of the amy-
laceous matter that had not been acted on by
the saliva and had passed unchanged into the
duodenum ; and he ascertained that both the
expressed secretion and an infusion of the
gland-substance exercised this transforming
property in a high degree. Bouchardat and
Sandras found that the pancreatic secretion
of fowls and geese possessed this property,
and immediately transformed starch into dex-
trine and grape sugar. On raising the fluid
to 100 (centigrade) it became inert ; but
the flocculi precipitated, either by heat or
alcohol, on being redissolved exerted an in-
fluence exactly the same as the original secre-
tion, and with the same power. In this albu-
minous substance they recognise the material
of which, under the name of diastase, they had
indicated the existence in the alimentary canal
of granivorous birds. They profess themselves
unable to define the action of this substance
compared with that of diastase. Like dias-
tase it is nitrogenous; and they regard it as
the principal agent in the digestion of feculent
aliments. They found, moreover, that a fluid
of similar properties might be obtained by
macerating for a short time portions of the
pancreas, finely minced, in an equal weight of
water. The fluid thus prepared converted
a thick starch jelly into a thin fluid, without
any viscosity, in the lapse of a few minutes.
By many alternate precipitations with alcohol
and solutions in water, as in the operation for
the purification of diastase, a flocculent pre-
cipitate was obtained, which, rapidly dried,
possessed a very energetic solvent power.
The existence of a principle acting like dias-
tase on fecula was equally demonstrated in
the rabbit, the dog, and man.*
Within the last few years an additional and
most important office has been claimed for
the pancreas by M. Bernardf that, namely,
of emulsifying or saponifying the neutral
fatty matters contained in the food, by de-
composing them into glycerine and their
respective fatty acids, and so rendering them
absorbable. M. Bernard bases his views on
two methods of proof on experiments on
the living animal, and on the secretion after
its removal ; and his whole paper is charac-
terised by an admirable completeness and
most orderly logic. The first series of ex-
periments consists in the admixture of various
fatty matters olive oil, butter, tallow, lard
with fresh pancreatic juice, alkaline, viscid,
and possessing all the characters of the nor-
mal secretion ; a temperature about that of
the body is applied, if necessary, and the
mixture agitated. In every case a smooth,
creamy emulsion is at once produced. In keep-
ing the products of these experiments at a
temperature above 100 Fahr. for fifteen or
eighteen hours, he says the emulsion was
perfectly maintained ; the appearance of the
white creamy liquid was quite unchanged,
nor was there, although kept in perfect re-
* Compt. Rend. t. 20. p. 1085.
f Archives Ge'n. de Medecine, iv. serie, 1. 19.
103
PANCREAS.
pose, an}' ssparation between the pancreatic
fluid and the fatty matters. After the lapse
of some hours it became evident that the
fat had not only been minutely subdivided
and emulsified, but that it had, furthermore,
been chemically modified. In fact the neu-
tral fatty matter and the alkaline pancreatic