The theory which I constructed for my own private use in accounting for
this phenomenon I offer with proper diffidence to others who may be in
search of a hypothesis to explain facts that they have observed. It is
this:

a. The circulation of the blood maintains health, and consequently life
by carrying away from the various parts of the body the particles of
worn-out and poisonous tissue, and replacing them with fresh,
structure-building material.

b. The man is healthiest in whom this process goes on most freely and
continuously.

c. Men of considerable muscular power are disposed to be sluggish; the
exertion of great strength does not favor circulation. It rather retards
it, and disturbs its equilibrium by congesting the blood in quantities in
the sets of muscles called into action.

d. In light, active men, on the other hand, the circulation goes on
perfectly and evenly, because all the parts are put in motion, and kept
so in such a manner as to promote the movement of the blood to every
extremity. They do not strain one set of muscles by long continued
effort, as a strong man does, but call one into play after another.

There is no compulsion on the reader to accept this speculation at any
valuation whatever. There is not even any charge for it. I will lay
down this simple axiom:

No strong man, is a healthy man