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DIGESTION IN THE STOMACH. 483
upon the pyloric sphincter. The proteins combine with the hydrochloric acid
and hence its action upon the sphincter becomes weaker, while this is not the
case with the carbohydrates. If the carbohydrates are moistened with alkali
tin y Leave the Btomach more slowly than usual, and the acid proteins, on the con-
trary, leave the stomach earlier than other proteins.
As our knowledge of the digestibility of the different foods in the
stomach is slight and uncertain, so also our knowledge of the action of
other bodies, such as alcoholic drinks, bitter principles, spices, etc., on
the natural digestion is very uncertain and imperfect. The difficulties
which stand in the way of this kind of investigation are very great, and
therefore the results obtained thus far are often ambiguous or conflict
with each other. For example, certain investigators have observed that
small quantities of alcohol or alcoholic drinks do not prevent but rather
facilitate digestion; others observed only a disturbing action, while
still others report having found that the alcohol first acts somewhat as
a disturbing agent, but afterward, when it is absorbed, produces and abun-
dant secretion of gastric juice, and thereby facilitates digestion. The
accelerating action of alcohol upon the flow of gastric juice has been
mentioned on page 464.
In regard to the importance of the stomach we used to be of the
general opinion that an abundant peptonization of protein does not
occur in the stomach, and that the food rich in protein is only
chiefly prepared in the stomach for the real digestion in the intestine.
That the stomach, at least the fundus, acts in the first place as a storage
chamber, follows from the shape of this organ, especially in certain
animals, and this function becomes especially prominent in certain new-
born animals, as dogs and cats. In these animals the gastric secretion
contains acid but no pepsin, and the casein of the milk is precipitated
by the acid alone as solid lumps or as a solid coagulum filling the
stomach. Gradually small quantities of this coagulum pass into the
intestine and an overburdening of the intestine is thus prevented. In
other animals, as the snake and certain fishes which swallow entire animals,
the major part of the digestive work goes on in the stomach. The
importance of the stomach for digestion cannot therefore be established
in all instances. It varies in different animals and differs even in indi-
vidual animals of the same species, depending upon the fineness or coarse-
ness of the food, upon the greater or less rapidity with which pepton-
ization takes place, and also upon the rapid or slow increment in the
quantity of hydrochloric acid, etc.
In regard to the extent of chemical digestive work, i.e., in the first
place the destruction of protein in the stomach, we have numerous
researches, some carried out by the use of older methods and others
by using newer and more reliable methods. Among these latter we
must mention those of Zunz, London and collaborators, Tobler, Lanq
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