rsons take it to kill pain and make them sleep.
You should never take it except when given by the doctor, as a habit
is quickly formed which will make you miserable through life.

=Patent Medicines.=--These are medicines advertised to cure ailments
which generally cannot be cured by drugs. They are the medicines much
advertised in the newspapers and magazines. Never use them unless your
doctor tells you to do so. Many of them contain harmful drugs, such as
morphine and alcohol. When you are sick, go to your doctor for advice.

PRACTICAL QUESTIONS

1. Explain how tobacco is raised.

2. How is tobacco used?

3. How does tobacco affect a boy using it for the first time?

4. What is the name of the poison in tobacco?

5. Tell how tobacco keeps boys from growing.

6. What countries do not allow boys to use tobacco?

7. What is meant by being a slave to tobacco?

8. What is tea?

9. What is coffee?

10. Why should you not use opium or morphine?

CHAPTER XII

THE SKIN AND BATHING

=Parts of the Skin.=--The skin is about as thick as the leather of
your shoe. It is fastened to the muscles beneath with fine white
threads like spider webs. This is called _connective tissue_ because
it connects the skin to the lean meat.

The skin is made of two layers (Fig. 45). The upper layer is formed of
cells. This is named _epidermis_ or _scarfskin_. The deeper layer is
made largely of fine threads woven together. It is the _true skin_ or
_derma_. There is no blood in the scarfskin, but there is a network of
blood tubes in the true skin. It is the crowding of these with blood
that makes the skin look so red when we get hot or excited.

=The Use of the Skin.=--The skin has three chief uses. It protects the
softer parts of the body from being hurt by rough or hard things which
might touch it. It contains the organs of feeling. It helps keep the
right amount of heat in the body.

[Illustration: FIG. 45.--A thin slice through the skin, showing sweat
glands, a nerve, and blood-tubes. Much enlarged.]

The top part of the skin is dry and dead. This gives better protection
than if it were moist and tender. Particles of it are wearing out and
dropping off while other bits are growing beneath to take the place of
the worn-out parts. The more this top skin is pressed on and rubbed,
the thicker it becomes. For this reason it is twice as thick in the
palms of the hand and o