ements of the stomach slower. This prevents the food from being
well and quickly mixed with the juices. Several glasses of beer used
at one meal will make the stomach do its work very slowly, and it will
not do it well.

=Wine and Digestion.=--Wine is taken by some people to give more
appetite for food. It is likely, however, to do more harm than good
because the alcohol in it makes the muscles which mix the food in the
stomach act more slowly. Some of the food may sour before it gets wet
with the juice. Much wine used at a meal is always harmful.

=Natural Appetite.=--If one is in health, he should feel a desire for
his food at every meal. This desire for a reasonable amount of food is
a natural appetite. Fresh air and exercise will do much to give one
the right kind of an appetite. The eating of much sweets and the
breathing of bad air are likely to spoil the appetite.

The use of some things, such as opium, tobacco, beer, wine, and
whisky, creates an unnatural appetite. That is, after one has used
these articles a few months he cannot stop their use without great
suffering. The younger the person, the sooner the appetite becomes
fixed. For this reason _young persons should never use tobacco or
alcoholic drinks of any kind_.

PRACTICAL QUESTIONS

1. What is digestion?

2. Name the parts of the food tube.

3. Where does saliva come from?

4. Explain how the food is acted on in the mouth.

5. Why should food be well chewed?

6. What forms the gastric juice?

7. Of what use is the gastric juice?

8. How long does food stay in the stomach?

9. Name some foods easily digested.

10. What does the intestine do?

11. What are villi?

12. Tell how the food gets into the blood.

13. Of what use is the liver?

14. Why should we not eat too much?

15. Should we eat between meals?

16. Give three reasons why you should not use tobacco.

CHAPTER VIII

THE CARE OF THE MOUTH

=Sickness often begins in the Mouth.=--A clean mouth and sound teeth
have much to do in keeping one well. The germs which cause nearly a
half million deaths in the United States every year enter the body
through the mouth. If the mouth is unclean, only one or two disease
germs entering it may remain there and grow.

[Illustration: FIG. 30.--The teeth of the upper jaw at eleven years of
age.]

It is just as important to wash the mouth two or three