athe deeper, even when we are
not thinking about doing so.

~11. Breathing through the Nose.~--In breathing, we should always take
care to draw the air in through the nose, and not through the mouth. The
nose acts as a strainer, to remove particles of dust which might do harm
if allowed to enter the lungs. It also warms and moistens the air in
cold weather. The habit of breathing through the mouth often gives rise
to serious disease of the throat and lungs.

~12. Effects of Alcohol and Tobacco upon the Lungs.~--Both alcohol and
tobacco produce disease of the breathing organs. Smoking injures the
throat and sometimes causes loss of smell. Serious and even fatal
diseases of the lungs are often caused by alcohol.

~13.~ Many people suppose that the use of alcohol will save a man from
consumption. This is not true. A man may become a drunkard by the use of
alcohol, and yet he is more likely to have consumption than he would
have been if he had been a total abstainer. "Drunkard's consumption" is
one of the most dreadful forms of this disease.

SUMMARY.

1. Pure air is as necessary as food and drink.

2. Anything which is rotting or undergoing decay causes a bad odor, and
thus makes the air impure.

3. Foul air contains germs which cause disease and often death.

4. Persons sick with "catching" diseases should be carefully avoided.
Such persons should be shut away from those who are well, and their
rooms and clothing should be carefully cleansed and disinfected.

5. The breath poisons the air about us. Each breath spoils half a
barrelful of air.

6. We should change the air in our houses, or ventilate them, so that we
may always have pure air.

7. We should always keep the body erect, and expand the lungs well in
breathing.

8. The clothing about the chest and waist should be loose, so that the
lungs may have room to expand.

9. Always breathe through the nose.

10. Tobacco causes disease of the throat and nose.

11. Alcohol causes consumption and other diseases of the lungs.

CHAPTER XV.

THE SKIN AND WHAT IT DOES.

~1. The Skin.~--The skin is the covering of the body. It fits so exactly
that it has the precise shape of the body, like a closely fitting
garment. If you will take up a little fold of the skin you will see that
it can be stretched like a piece of india-rubber. Like rubber, when it
is released it quickly contracts and appears as before.

~2. The Bark of Trees.~--Did you ever pee