The effect of vitiated air is well known. The necessity, not only
for breathing fresh air when we are quiet, but for exercising in the
open, grows upon us as we see the result. To feel the need is to
take the remedy, as a matter of course.

The rest-instinct is most generally disobeyed, most widely needed,
and obedience to it would bring the most effective results. A
restful state of mind and body prepares one for the best effects
from exercise, fresh air, and nourishment. This instinct is the more
disobeyed because with the need for rest there seems to come an
inability to take it, so that not only is every impediment
magnified, but imaginary impediments are erected, and only a decided
and insistent use of the will in dropping everything that
interferes, whether real or imaginary, will bring a whiff of a
breeze from the true rest-current. Rest is not always silence, but
silence is always rest; and a real silence of the mind is known by
very few. Having gained that, or even approached it, we are taken by
the rest-wind itself, and it is strong enough to bear our full
weight as it swings us along to renewed life and new strength for
work to come.

The secret is to turn to silence at the first hint from nature; and
sleep should be the very essence of silence itself.

All this would be very well if we were free to take the right amount
of rest, fresh air, exercise, and nourishment; but many of us are
not. It will not be difficult for any one to call to mind half a
dozen persons who impede the good which might result from the use of
these four necessities simply by complaining that they cannot have