When the arteries have been made large very often, they stay large all the time. A drinker's nose is often red from this cause.
Alcohol sometimes causes the arteries to become hard, and even to change to a kind of bone. Then they cannot change their size to carry just so much blood as each part needs.
99. How tobacco affects the heart.—Tobacco weakens all the body, but it harms the heart more than the rest. It often makes the heart beat slowly at one time and fast at another. It weakens the heart and keeps it from working harder when the working cells need more food. A smoker gets out of breath quickly. He cannot run far or work very hard. Chewing is a still more harmful form of using tobacco. When men train for a game or a race they never use tobacco.
Boys are not so strong as men, and so tobacco is more hurtful to them. Boys are harmed by tobacco far more than men. Cigarette smoke harms their stomachs and keeps food from their blood. If boys smoke, they become pale and weak. The poisonous smoke weakens the heart, and they cannot run or work so hard as they should. Even if a father uses tobacco, he should not allow his boys to use it.
WHAT WE HAVE LEARNED
1. Blood is a liquid. It contains many round red cells and a few white cells.
2. Blood contains all kinds of food for the cells of the body.
3. The blood is kept moving by the heart.
4. The heart pumps or beats about seventy times a minute.
5. The blood flows through arteries to all parts of the body.