other, and to keep the food between the teeth.

~3. Mouth Digestion.~--While the bread is being chewed, the saliva is
mixed with it and acts upon it. The saliva moistens and softens the food
so that it can be easily swallowed and readily acted upon by the other
digestive juices. You have noticed that if you chew a bit of hard bread
a few minutes it becomes sweet. This is because the saliva changes some
of the starch of the food into sugar.

~4.~ After we have chewed the food, we swallow it, and it passes down
through the oesophagus into the stomach.

~5. Stomach Digestion.~--As soon as the morsel of food enters the
stomach, the gastric juice begins to flow out of the little glands in
which it is formed. This mingles with the food and digests another
portion which the saliva has not acted upon. While this is being done,
the stomach keeps working the food much as a baker kneads dough. This is
done to mix the gastric juice with the food.

~6.~ After an hour or two the stomach squeezes the food so hard that a
little of it, which has been digested by the gastric juice and the
saliva, escapes through the lower opening, the pylorus, of which we have
already learned. As the action of the stomach continues, more of the
digested food escapes, until all that has been properly acted upon has
passed out.

~7. Intestinal Digestion.~--We sometimes eat butter with bread, or take
some other form of fat in our food. This is not acted upon by the saliva
or the gastric juice. When food passes out of the stomach into the small
intestine, a large quantity of bile is at once poured upon it. This bile