ividual, pushing his energies to their extreme,
may in a vast number of cases keep the pace up day after day, and find
no "reaction" of a bad sort, so long as decent hygienic conditions are
preserved. His more active rate of energizing does not wreck him; for
the organism adapts itself, and as the rate of waste augments, augments
correspondingly the rate of repair.

I say the _rate_ and not the _time_ of repair. The busiest man needs
no more hours of rest than the idler. Some years ago Professor
Patrick, of the Iowa State University, kept three young men awake for
four days and nights. When his observations on them were finished, the
subjects were permitted to sleep themselves out. All awoke from this
sleep completely refreshed, but the one who took longest to restore
himself from his long vigil only slept one-third more time than was
regular with him.

If my reader will put together these two conceptions, first, that few
men live at their maximum of energy, and second, that anyone may be in
vital equilibrium at very different rates of energizing, he will find,
I think, that a very pretty practical problem of national economy, as
well as of individual ethics, opens upon his view. In rough terms, we
may say that a man who energizes below his normal maximum fails by just
so much to profit by his chance at life; and that a nation filled with
such men is inferior to a nation run at higher pressure. The problem
is, then, how can men be trained up to their most useful pitch of
energy? And how can nations make such training most accessible to all
their sons and daughters. This, after all, is only the general problem
of education, formulated in slightly different terms.

"Rough" terms, I said just now, because the words "energy" and
"maximum" may easily suggest only _quantity_ to the reader's mind,
whereas in measuring the human energies of which I speak, qualities as
well as quantities have to be taken into account. Everyone feels that
his total _power_ rises when he passes to a higher _qualitative_ level
of life.

Writing is higher than walking, thinking is higher than writing,
deciding higher than thinking, deciding "no" higher than deciding
"yes"--at least the man who passes from one of these activities to
another will usually say that each later one involves a greater element
of _inner work_ than the earlier ones, even though the total heat given
out or the foot-pounds expended by the organism, may be less.