~3. Healthful Exercise.~--Some kinds of play, and almost all kinds of work which children have to do, are good ways of taking exercise. A very good kind of exercise for little boys and girls is that found in running errands or doing chores about the house. ~4. Food and Strength.~--A great part of our food goes to nourish the muscles. Some foods make us strong, while others do not. Plain foods, such as bread, meat, potatoes, and milk, are good for the muscles; but cakes and pies, and things which are not food, such as mustard, pepper, and spices, do not give us strength, and are likely to do us harm. ~5. Over-Exertion.~--We ought not to exert ourselves too much in lifting heavy weights, or trying to do things which are too hard for us. Sometimes the muscles are permanently injured in this way. ~6. The Clothing.~--We ought not to wear our clothing so tight as to press hard upon any part of the body. If we do, it will cause the muscles of that part to become weak. If the clothing is worn tight about the waist, great mischief is often done. The lungs cannot expand properly, the stomach and liver are pressed out of shape, and the internal organs are crowded out of their proper places. ~7. Tight Shoes.~--People are often made very lame from wearing tight shoes. Their muscles cannot act properly, and their feet grow out of shape. ~8.~ In China, it is fashionable for rich ladies to have small feet, and they tie them up in cloths so that they cannot grow. The foot is squeezed out of shape. Here is a picture of a foot which has been treated in this way. It does not look much like a human foot, does it? A woman who has such feet finds it so difficult to walk that she has to be carried about much of the time. Do you not think it is very wrong and foolish to treat the feet so badly? You will say, "Yes;" but the Chinese woman thinks it is a great deal worse to lace the clothing tight about the body so as to make the waist small. [Illustration: FOOT OF CHINESE WOMAN.] ~9. Effects of Alcohol upon the Muscles.~--When an intemperate man takes a glass of strong drink, it makes him feel strong; but when he tries to lift, or to do any kind of hard work, he cannot lift so much nor work so hard as he could have done without the liquor. This is because alcohol poisons the muscles and makes them weak. ~10. Effects of Drunkenness.~--When a man has become addicted to strong drink, his muscles become partly paralyzed, so that he cannot walk as steadily or speak as readily or as clearly as before. His fingers are clumsy, and his movements uncertain. If he is an artist or a jeweller, he cannot do as fine work as when he is sober. When a man gets very drunk, he is for a time completely paralyzed, so that he cannot walk or move, and seems almost like a dead man.