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480 DIGESTION.
The fundus part is therefore less a digestion-organ than a storage-organ,
and in the interior of the same, the food may remain for hours without
coming in contact with a trace of gastric juice.
What has been said above applies at least to solid food. We have
no extensive observations on the behavior of fluids or semifluid food.
According to Grutzner, in these cases, as well as in the above-mentioned
experiments, the swallowed foodstuffs are not irregularly mixed together.
Fluids quickly leave the stomach, which is also the case with a mixture
of solid and fluid food.
Milk is an exception because it coagulates and the clot remains in the
stomach while the whey quickly leaves the stomach.
The fact that only that part of the ingesta lying on the mucous
membrane is mixed with gastric juice, while the mass in the interior is
not acid in reaction, is of special importance for the digestion of starches
in the stomach. By this we can explain why the salivary diastase,
although sensitive toward acids, can continue its action for a long time
in the contents of the stomach. That this is true was first found by
Ellenberger and Hofmeister and then by Cannon and Day * by
special experiments upon animals. The occurrence of sugar and dex-
trin in the contents of the human stomach has been repeatedly observed.
In carnivora, whose saliva shows scarcely any diastatic action, it is
a ’priori not expected that there should be a diastatic action in the
stomach, but the conditions are different in herbivora, where an abun-
dant digestion of starch takes place in the various stomachs, according
to the different species.
The gastric contents which have been prepared in the pylorus part
are passed through the pylorus into the intestine intermittently. This’
material is generally fluid, but it is possible that pieces of solid food
may also occur, and this has often been observed. Thin or plastic
food leaves the stomach earlier than solid food, and it is obvious that the
time in which the stomach unburdens itself depends naturally upon
the coarseness or fineness of the food. This depends essentially upon
the reflex action of the stomach or intestine, causing an opening or
closing of the pylorus, which action is dependent upon the quantity and
character of the food, the amount of fat, and the degree of acidity in
the contents of the stomach and intestine. The emptying of the food
into the small intestine causes, as shown by Pawlow, a closing of the
pylorus by chemo-reflex in which the hydrochloric acid and the fat take
part, and we thus find in this regard an alternate action between the
stomach and duodenum.
1
EllenberRer and Hofmeister, Maly’s Jahresb., 15 and 16; Cannon and Day, Amer.
Journ. of Physiol.. 9.
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