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514 DIGESTION.
tained 73 per cent of the coagulable protein from a fistula in the ileum
(2-3 cm. in front of the caecum). Elastin is, according to London, *
more slowly digested in the small intestine than other proteins. Kut-
scher and Seemann, Abderhalden, London and collaborators 2
have
also found that non-biuret giving products and amino-acids are regularly
split off, probably by the combined action of trypsin and erepsin. These
amino-acids occur to a slight extent only, but from this no conclusion
can be drawn as to the extent of amino-acid formation, because we do
not know the extent of their absorption. The digestion of protein
in the intestine, it seems, according to Abderhalden, London, Oppler
and Reemlin,3
is similar to the artificial digestion with trypsin, nainely,
that the destruction takes place step-wise, that certain amino-acids,
such as tyrosine, are split off earlier than others. Zunz 4
found the same
end result in the protein cleavage in the small intestine, with bread as
with meat feeding. London, Schittenhelm and Wiener 5
found
that a cleavage of nucleic acids with the formation of nucleosides
occurred in the lower part of the jejunum and ileum.
The decomposition products of the proteins formed by the action of
gastric juice can, according to London, 6 be absorbed without further
cleavage by the pancreatic juice, and a further cleavage in the intestine
seems to be more necessary for assimilation than for absorption.
The carbohydrates and the fats (Levites 7
) may be so completely
split in the stomach and small intestine that their absorption is com-
plete before the contents pass into the caecum. According to London
and Polowzowa 8
a strong cleavage of starch, dextrins and disaccharides
takes place, especially in the duodenum, while the absorption is less
strong here. The carbohydrates are here prepared for the absorption
taking place in the lower parts of the intestine, though the cleavage also
goes on in the other parts, namely in the jejunum and the upper part
of the ileum.
As above remarked, ordinarily no putrefaction takes place in the
small intestine, but occurs generally only in the large intestine. This
1
London and Suleima, Zeitschr. f. physiol. Chem., 46; London, ibid., 60.
2
Kutscher and Seemann. ibid., 34; Abderhalden and London, with Kautzsch,
ibid., with L. Baumann, ibid., 51, with v. Korosy, ibid., 53.
3
Zeitschr. f. physiol. Chem., 55 and 58.
4
Intern. Beitr. z. Pathol, u. Ther. d. Ernahrungsstorungen, 2, 195, 459 (1910 and
1911).
’>
Zeitschr. f. physiol. Chem., 72, 459 (1911).
• Ibid., 49.
7
Ibid., 49 and 53.
y
Ibid., 56.
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