16.  Tea and Coffee.—­Strong tea and coffee, while by no means so bad as alcohol and tobacco, may make us weak and sick.  A person who drinks strong tea or coffee feels less tired while at work than if he had not taken it, but he is more tired afterwards.  So you see that tea and coffee are also whips, small whips we might call them, and yet they really act in the same way as do other narcotics and stimulants.  They make a person feel stronger than he really is, and thus he is led to use more strength than he can afford to do.

SUMMARY.

1.  We must use the muscles to make them grow large and strong.

2.  Exercise should be taken regularly.

3.  Exercise makes the muscles strong, the body beautiful, the lungs active, the heart vigorous, and the whole body healthy.

4.  Things we ought not to do:  To run or play hard just before or after eating; to strain our muscles by lifting too heavy weights; to exercise so violently as to get out of breath; to lie, sit, stand, or walk in a cramped position, or awkward manner; to wear the clothing so tight as to press hard upon the muscles.

5.  Good food is necessary to make the muscles strong and healthy.

6.  Alcohol makes the muscles weak, although at first it makes us feel stronger.

7.  A boy who uses tobacco will not grow as strong and well as one who does not.

8.  The use of strong tea and coffee may injure the muscles.

CHAPTER XXII.

HOW WE FEEL AND THINK.

1.  How we Think.—­With what part of the body do we think?  You will at once say that we think with the head; but we do not think with the whole head.  Some parts of the head we use for other purposes, as the mouth to eat and speak with, and the nose to smell and breathe with.  The part we think with is inside of the skull, safely placed in a little room at the top and back part of the head.  Do you remember the name of this organ which fills the hollow place inside of the skull?  We learned some time ago that it is called the brain.  It is with the brain that we study and remember and reason.  So the brain is one of the most important organs in our body, and we must try to learn all we can about it.

2.  The Brain.—­You cannot see and examine your own brain because it is shut up in the skull; but perhaps you can find the brain of a sheep or a calf at the meat market.  The brain of one of these animals looks very nearly like your own.

3.  The Large Brain and the Small Brain.—­In examining a brain we should notice first of all that there are really two brains, a large brain and a small brain.  The large brain is in the top and front of the skull, and the small one lies beneath the back part of the larger one, If we look again we shall see that each brain is divided in the middle into a right and a left half.  Each half is, in fact, a complete brain, so that we really have two pairs of brains.