allowed. It must be spit out, and with it is sent the saliva that was
needed to help prepare the food.

Tobacco discolors the teeth, makes bad sores in the mouth, and often
causes a disease of the throat.

You can tell where some people have been, by the neatness and comfort
they leave after them.

You can tell where the tobacco-user has been, by the dirty floor, and
street, and the air made unfit to breathe, because of the smoke and
strong, bad smell of old tobacco from his pipe and cigar and from his
breath and clothes.

REVIEW QUESTIONS.

1. What are organs?

2. What work do the front teeth do? the back
teeth?

3. What are the teeth made of?

4. What causes the toothache?

5. How is the enamel often broken?

6. Why should a tooth-pick be used?

7. Why should the teeth be well brushed?

8. When should they be brushed?

9. What bones form a case or box?

10. What is the upper room of this box called? the
lower room?

11. What organs are in the chest? the abdomen?

12. What is the stomach?

13. What does its lining do?

14. What do the stomach and the gastric juice do
to the food we have eaten?

15. How did anybody find out what the stomach
could do?

16. Why must all the food we eat be changed?

17. Why do you need food?

18. Why do people who are not growing need food?

19. What does alcohol do to the gastric juice? to
the stomach?

20. What is the use of the saliva?

21. How does the habit of spitting injure a
person?

22. How does tobacco affect the teeth? the mouth?

23. How does the tobacco-user annoy other people?

FOOTNOTE:

[Footnote C: The food is partly prepared by the liver and some other
organs.]

CHAPTER XI.

WHAT DOES THE BODY NEED FOR FOOD?

[Illustration: N]OW that you know how the body is fed, you must next
learn what to feed it with; and what each part needs to make it grow and
to keep it strong and well.

WATER.

A large part of your body is made of water. So you need, of course, to
drink water, and to have it used in preparing your food.

Water comes from the clouds, and is stored up in cisterns or in springs
in the ground. From these pipes are laid to l