CHAPTER XXI.

HOW TO KEEP THE MUSCLES HEALTHY.


~1. How to Make the Muscles Strong.~--With which hand can you lift the
more? with the right hand or with the left? Why do you think you can
lift more with the right hand than with the left? A blacksmith swings a
heavy hammer with his right arm, and that arm becomes very large and
strong. If we wish our muscles to grow large and strong, so that our
bodies will be healthy and vigorous, we must take plenty of exercise.

~2. Effects of Idleness.~--If a boy should carry one hand in his pocket
all the time, and use only the other hand and arm, the idle arm would
become small and weak, while the other would grow large and strong. Any
part of the body which is not used will after a time become weak. Little
boys and girls who do not take plenty of exercise are likely to be pale
and puny. It is important that we should take the proper amount of
exercise every day, just as we take our food and drink every day.

~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