HEALTH EXERCISES 453
it without thinking of it, why not establish that same habit in every schoolroom in America? Pupils, at all times, should sit far back on the seat and hold the chin well drawn in toward the neck. The more you draw it in, the more you enlarge your chest. At first it will tire a few muscles a little. But that is of no account. Make the fight, and never give up till you win. No matter how many times you forget or fail, do it again and again, until you find—as you will in a few days—that it is just as easy for you, as it is for a West Pointer, always to hold yourself erect, while sitting or standing ; you thus keep your vital-house in such a posture that every vital organ has full room to do good work, as it has* not when you stoop.
The Lungs and the Heart
Many athletic persons think that it is more important to have the upper half of the chest larger than the lower; that if you measure large around the chest as close under the arms as you can, that is the main thing in having a fine chest. But only the small end of each lung is in the upper half of the chest.
Far the greater part of the lungs is the lower half. Here also is the heart. So if you want large lungs, and a strong, easy-working heart, you must make their house—the lower half of tne chest—as deep and roomy as you can. Whenever you find any one who can outlast others at any kind of really severe muscular exercise, you will almost always find that his lower chest is unusually large. There, we may observe, Webster's was enormous.
There is a broad, thin, pancake-shaped muscle, lying like a great rug, directly under both your lungs. It is called the diaphragm. This is the great breathing muscle. It also is the great singing muscle. Every time you draw in a breath you push the middle of this muscle downward, and you press upon all the vital organs below it, so helping them to be more active and to do better work. When you breathe out, the middle of the diaphragm rises again. Watch a sleeping dog, and see