Bauhaus-Universität Weimar

Titel:
The Cyclopaedia of Anatomy and Physiology, vol. 5: Supplementary Volume
Person:
Todd, Robert Bentley
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit36060/177/
PANCREAS. 
Bat these views, so neat and complete in 
themselves, and so nicely put forth by Ber¬ 
nard, have of late been vigorously assailed by 
the German school, and their fidelity and 
conclusiveness altogether impugned. Frerichs, 
and Bidder and Schmidt, have, by a repetition 
of Bernard’s experiments, as well as by many 
ingenious and well-devised ones of their own, 
failed to verify any of his results, but have been 
led by them to conclusions with which they are 
altogether discrepant. These experimenters 
state that they carefully followed all Bernard’s 
directions — they tied the pancreatic duct, 
and, having previously kept the animals on 
short food from twelve to twenty-four hours 
so that there might be no remains of the se¬ 
cretion in the intestine, fed them with fatty 
aliment, and killed them in from four to eight 
hours. They always found the lacteals 
“most beautifully injected, and the recep- 
taculum chyli distended with milky chyle.” 
Frerichs found on tying the' small intes¬ 
tine some distance below the opening of 
the pancreatic and bile ducts in cats and 
puppies, and injecting into the bowel below the 
ligature olive oil and milk, that after two or 
three hours the lacteals were filled with white 
chyle. He, however, believes that he has 
found the extreme comminution of fat, and 
hence in some measure its resorption, pro¬ 
moted by the bile and pancreatic juice ; for 
when in cats that had long fasted, he cut 
through the small intestine near the middle, 
injected olive oil into both halves, and tied 
the two cut extremities, he found the lacteals 
springing from the upper part of the intestine 
always far more injected than those proceed¬ 
ing from the lower, which he attributes to the 
bile and pancreatic juice having access to the 
fat in the upper portion. 
With regard to the permanence of the 
emulsion produced by the mixture of pan¬ 
creatic juice and fat out of the body, Fre¬ 
richs and Bernard are quite at issue; for 
while Bernard states, that on being examined 
fifteen or eighteen hours afterwards, it was 
found to be perfectly maintained, Frerichs 
affirms that the particles of oil soon separate 
again on the surface. 
There certainly are some circumstances 
which detract from the conclusiveness of Ber¬ 
nard’ s experiments : one is, that the chyle 
contains far less fatty acids than the ordinary 
neutral fats ; another, that other animal 
fluids, as soon as they begin to putrefy, cause 
a similar decomposition of the neutral fats ; 
another, that Bernard’s experiments merely 
had reference to the production of this change 
out of the body. This last deficiency has been 
filled up by Lenz* He fed healthy cats with 
fresh butter, or, if necessary, injected it into 
their stomachs, and killed them in from six 
to fourteen hours afterwards. Although all 
the lacteals and the thoracic duct were dis¬ 
tended with milky chyle, no trace of butyric 
acid could be detected in the stomach and 
intestinal canal, or in the thoracic duct, the 
* De Adipis Concoctione et Absorptione. Inaug. 
Diss. Dorp. Liv. 1850. 
portal vein, or gall-bladder. By further ex¬ 
perimental investigation, he found that the 
metamorphic action was hindered by the acid 
gastric juice in proportion to the amount of 
free acid present, that a similar action might 
be artificially induced by other acids, as di¬ 
luted lactic, tartaric, and acetic acid, and that 
it might be overcome by neutralising the free 
acid by bile, or by an alkali. Hence he con¬ 
cluded, that it is only in exceptional cases that 
the pancreatic fluid decomposes the neutral 
fats into acids and bases in the living body. 
The argument derived from the experiment 
on rabbits has been thus explained away by Bid¬ 
der andSchmidt. They say that if the rabbit is 
killed two hours after the fat has been given 
it the lacteals given off between the pylorus 
and the mouth of the pancreatic duct, are fully 
distended with white chyle very rich in fat ; 
if not till four hours after the injection, the 
lacteals situated about three or four inches 
above the mouth of the duct are still filled ; 
if at six hours, those only below the duct con¬ 
tain white chyle ; and if not till eight or ten 
hours after, the first lacteals well injected with 
milky chyle are found to be situated ten or 
twelve inches below the duct. Hence it must 
have been by always killing the animals six or 
eight hours after feeding them with fat, that 
Bernard was able apparently to maintain his 
view. The facts of the case, say they, were 
simply these. The chyle had already passed on¬ 
wards from the lymphatics proceeding from the 
first portion of the duodenum, and there was no 
more fat to be absorbed in that portion of the 
intestine when Bernard began the investiga¬ 
tion. I cannot admit the correctness of this 
explanation given by Schmidt and Bidder, 
because some of the rabbits on which I re¬ 
peated Bernard’s experiments and verified his 
results were killed within four, or even three 
hours after the injection of the lard. 
It was formally maintained by MM. Ber¬ 
nard and Barreswill, that the pancreatic juice 
when acidified had an equally solvent power 
on the precipitated protein compounds with 
the gastric juice, and that its acidity or alka¬ 
linity alone determined whether it should act 
on albuminous or amylaceous matters. This 
opinion has also been refuted by Frerichs. 
Lastly, this physiologist ascribes to the pan¬ 
creatic fluid a peculiar power of hastening the 
conversion of the bile into insoluble products, 
and so favouring its more perfect elimination. 
This view has been completely overthrown by 
the experiments of Bidder and Schmidt, who 
have shown, first, that the greater part of the 
bile is not thrown off with the faeces, as 
Frerichs believes ; and, secondly, that the 
lime, to which Frerichs especially ascribes 
this power, only exists in very subordinate 
quantity in the pancreatic fluid.* 
In taking a review of all that has been done 
with regard to the functions of the pancreatic 
secretion, we must, admit that the only one 
that has been established beyond dispute is its 
sugar-making action on amylaceous matters. 
* British and Foreign Med. Chir. Review. On the 
“ Chemistry of Digestion,” by Dr. Day.
        

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