juice of these with
that of the other glands softens the food and makes it into a liquid.

=The Work of the Mouth.=--The mouth has three things to do: It should
break the lumps of food into fine bits so it can be well wet with the
slippery fluid called _saliva_ and also easily swallowed. It must roll
the food about so that it gets soaked with saliva. It must hold the
food long enough to get much taste from it because this starts the
juices to flowing into the stomach. Food gives out its taste only
after it is changed to a liquid. It should not be washed down with
water, as this weakens the juices in the stomach.

[Illustration: FIG. 24.--The three glands which make the saliva for
acting on the food in the mouth.]

No food should be swallowed until it is broken into bits nearly as small
as the head of a pin. Some foods, such as cheese, bananas, and nuts,
should be made even finer than this. There is nothing in the stomach to
crush to pieces large lumps of food. The juices of the stomach can do
their full work only when the food is well chewed in the mouth.

[Illustration: FIG. 25.--Photograph of a chestnut chewed a half minute
by a boy who had poor teeth because he had not taken care of them. The
lumps are so large that the juices of the stomach could not dissolve
them.]

=The Chewing of Food keeps away Sickness.=--Bread, meat, and potatoes
should be cut into pieces no larger than half the size of your thumb
and each piece put separately into your mouth with a fork. It should
then be chewed from twenty to thirty times before another piece is put
into the mouth. Food treated in this way will not cause headache or a
sickness in the stomach called _indigestion_ or _dyspepsia_. It is
said that there are so many persons with this kind of sickness that
more than $5,000,000 are spent every year for medicine to help them.

Too little chewing of the food while you are young may not cause many
aches or pains, but if you form the habit of rapid eating it is hard
to learn to eat slowly. No one who chews his food poorly can avoid
sickness long or grow well and strong.

[Illustration: FIG. 26.--Photograph of a chestnut chewed a half minute
by a boy with good teeth.]

=The Work of the Stomach.=--When the food is swallowed, it passes
through the gullet into the stomach. This is a sac holding more than
a quart (Fig. 27). It is made of an outer wall of muscle and an inner
skinlike coat full of tiny tubes called _gastric glands_.