act; and though some men be so strong that they can sit up all night occasionally, they cannot continue to do so for many nights together.
This nightly good-by to self and surroundings would certainly prove startling were it a thought more rare. As it is, so little are we disturbed at the idea of it that we actually assist at our own apparent annihilation. We not only put ourselves to bed, but usually to sleep every night. We help nature close our eyes, and compose what is left of our minds to absolute inaction. To a certain extent we thus hypnotize ourselves nightly. Indeed, as our minds grow less active with years, some of us find no difficulty in performing this feat in the daytime.
All of which shows that the force which runs the brain machinery is regularly exhausted by action, and has to be as regularly recruited by rest. For that the force has the power to store itself up again is proved by the fact that we ever wake.
So soon as mental activity has thus been reduced to a minimum, and we are sound asleep, the potential begins to rise. Debarred from flowing, the stream of thought
