.~--Bad air is very harmful to the heart and to
the blood also. We should always remember that the blood of the body
while passing through the lungs is exposed to the air which we breathe.
If the air is impure, the blood will be poisoned. In churches and in
other places where the air becomes foul, people often faint from the
effects of the impure air upon the heart. It is important that the air
of the rooms in which we live and sleep should be kept very pure by good
ventilation.

~4. Effects of Bad Food.~--The blood is made from what we eat, and if we
eat impure and unwholesome food, the blood becomes impure. We ought to
avoid the use of rich or highly-seasoned foods, candies, and all foods
which are not nutritious. They not only injure the blood by making it
impure, but they cause poor digestion.

~5. Plenty of Sleep Necessary.~--If we should take a drop of blood from
the finger of a person who had not had as much sleep as he needed, and
examine it with a microscope, we should find that there were too few of
the little red-blood corpuscles. This is one reason why a person who has
not had sufficient sleep looks pale.

~6. Proper Clothing.~--We should be properly clothed, according to the
weather. In cold weather we need very warm clothing. In warm weather we
should wear lighter clothing. Our clothing should be so arranged that it
will keep all parts of the body equally warm, and thus allow the blood
to circulate properly. The feet are apt to be cold, being so far away
from the heart, and we should take extra pains to keep them warm and
dry.

~7. Effects of Excessive Heat.~--In very hot weather, many persons are
injured by exposing themselves to the sun too long at a time. Persons
who drink intoxicating liquors are very often injured in this way, and
sometimes die of sunstroke.

~8. Effects of Anger.~--When a person gets very angry, the heart
sometimes almost stops beating. Indeed, persons have died instantly in a
fit of passion. So you see it is dangerous for a person to allow himself
to become very angry.

~9. Effects of Alcohol upon the Blood.~--If you should take a drop of
blood upon your finger, and put it under the microscope, and then add a
little alcohol to it, you would see that the corpuscles would be quickly
destroyed. In a few seconds they would be so shrivelled up that no one
could tell that they had ever been the beautiful little corpuscles which
are so necessary to health. When alcohol is taken as a