er do get our
lungs filled with fresh air. What really happens is that we ventilate a
long tube which has no intercommunication whatever with the blood. Most
of the time our lungs are filled with impure air, and we simply exchange
a part of it for fresh air.

THE VALUE OF DEEP BREATHING

Deep breathing is undoubtedly extremely beneficial. Most of us, due
largely to the fact that Nature leaves a considerable margin of safety,
are able to carry on our ordinary activities without the requisite
ventilation of the lungs, especially if we do not exercise. This,
however, is injurious to the lungs, for it allows the blood to stagnate
in them. Exercise is Nature's method of compelling ventilation in the
lung area. Deep breathing may be used as a substitute, but the other
beneficial effects of exercise are lost.

The skin and the various glands connected with it form a complex
organism, the functions of which play a very important part in the work
which the body has to do. The skin aids the lungs in their work of
respiration; and, like the lungs, it throws off water and carbon dioxide
and absorbs oxygen. The respiratory work of the skin, however, is only a
minute fraction of that which the lungs do.

The skin is a heat regulator, and in this, its most important work, it
is aided by the two million or more sweat-glands which are distributed
over almost the entire surface of the body. The skin and the
sweat-glands work together to keep the blood at an even temperature,
either by giving off heat or in preventing this process in case the
outside air is too cool. The body temperature, as a rule, is higher than
that of the outside air, so that heat is generally being given off by
the skin. We are perspiring constantly, but usually to such a slight
extent that the fact is hardly noticeable. The amount of heat which is
thrown off at any time is proportional to the amount of the tissue
burned up by muscular action.

CHAPTER V

Health, strength, and efficiency! Surely every man in this great
Republic of ours wants to be healthy, strong, and efficient, but how is
he to obtain and maintain this threefold blessing? It has been stated
that scientific physical exercise, preferably taken in group
association, will accomplish it. Now to consider some of the practical
details involved.

THE ORGANIZATION

The organization may be composed of any number from sixteen to one
hundred men, and about the smallest unit that should be