A Handbook of Health | Page 7

to taste sweetish.
This change in the mouth, however, is not of such great importance as
we at one time thought, because even with careful mastication, a certain
amount of starch will be swallowed unchanged. Nature has provided
for this by causing another gland farther down the canal, just beyond
the stomach, called the pancreas, to pour into the food tube a juice
which is far stronger in sugar-making power than the saliva, and this
will readily deal with any starch which may have escaped this change
in the mouth. Moreover, this "sugaring" of starch goes on in the
stomach for twenty to forty minutes after the food has been swallowed.
Starchy foods, like bread, biscuit, crackers, cake, and pastry, are really
the only ones which require such thorough and elaborate chewing as we
sometimes hear urged. Other kinds of food, like meat and eggs--which
contain no starch and consequently are not acted upon by the
saliva--need be chewed only sufficiently long and thoroughly to break
them up and reduce them to a coarse pulp, so that they can be readily
acted upon by the acid juice of the stomach.
Down the Gullet. When the food has been thoroughly moistened and
crushed in the mouth and rolled into a lump, or bolus, at the back of the
tongue, it is started down the elevator shaft which we call the gullet, or

esophagus. It does not fall of its own weight, like coal down a chute,
but each separate swallow is carried down the whole nine inches of the
gullet by a wave of muscular action. So powerful and closely applied is
this muscular pressure that jugglers can train themselves, with practice,
to swallow standing on their heads and even to drink a glass of water in
that position; while a horse or a cow always drinks "up-hill." This
driving power of the food tube extends throughout its entire length; it is
carried out by a series of circular rings of muscles, which are bound
together by other threads of muscle running lengthwise, together
forming the so-called muscular coat of the tube. By contracting, or
squeezing down in rapid succession, one after another, they move the
food along through the tube. The failure of these little muscles to act
properly is one of the causes of constipation and biliousness.
Sometimes the action of the muscles is reversed, and then we get a
gush of acid, or bitter, half-digested food up into the mouth, which we
call "heart-burn" or "water-brash."
The Stomach--its Shape, Position, and Size. By means of muscular
contraction, then, the gullet-elevator carries the food into the stomach.
This is a comparatively simple affair, merely a ballooning out, or
swelling, of the food tube, like the bulb of a syringe, making a pouch,
where the food can be stored between meals, and where it can undergo
a certain kind of melting or dissolving. This pouch is about the shape of
a pear, with its larger end upward and pointing to the left, and its
smaller end tapering down into the intestine, or bowel, on the right, just
under the liver. The middle part of the stomach lies almost directly
under what we call the "pit of the stomach," though far the larger part
of it lies above and to the left of this point, going right up under the ribs
until it almost touches the heart, the diaphragm only coming between.[3]
This is one of the reasons why, when we have an attack of indigestion,
and the stomach is distended with gas, we are quite likely to have
palpitation and shortness of breath as well, because the gas-swollen left
end of the stomach is pressing upward against the diaphragm and thus
upon the heart and the lungs. Most cases of imagined heart trouble are
really due to indigestion.
The Lining Surface of the Stomach. Now let us look more carefully at

the lining surface of the stomach, for it is very wonderful. Like all other
living surfaces, it consists of tiny, living units, or "body bricks" called
cells, packed closely side by side like bricks in a pavement. We speak
of the mucous membrane, or lining, of our food tube, as if it were one
continuous sheet, like a piece of calico or silk; but we must never forget
that it is made up of living ranks of millions of tiny cells standing
shoulder to shoulder.
These cells are always actively at work picking out the substances they
need, and manufacturing out of them the ferments and acids, or alkalies,
needed for acting upon the food in their particular part of the tube,
whether it be the mouth, the stomach, or the small intestine.
[Illustration: A SECTION OF THE LINING SURFACE OF THE
STOMACH
(Greatly magnified)
Showing the mouths of the stomach