This is not reversion, but partly expression of the nature and perhaps the needs of this stage of immaturity, and partly the same instinct of revolt against uniformity imposed from without, which rob life of variety and extinguish the spirit of adventure and untrammeled freedom, and make the savage hard to break to the harness of civilization. The hunger for fatigue, too, can become a veritable passion and is quite distinct from either the impulse for activity for its own sake or the desire of achievement. To shout and put forth the utmost possible strength in crude ways is erethic intoxication at a stage when every tissue can become erectile and seems, like the crying of infants, to have a legitimate function in causing tension and flushing, enlarging the caliber of blood vessels, and forcing the blood perhaps even to the point of extravasation to irrigate newly growing fibers, cells, and organs which atrophy if not thus fed. When maturity is complete this need abates. If this be correct, the phenomenon of second breath, so characteristic of adolescence, and one factor in the inebriate's propensity, is ontogenetic expression of a rhythm trait of a long racial period. Youth needs overexertion to compensate for underexertion, to undersleep in order to offset oversleep at times. This seems to be nature's provision to expand in all directions its possibilities of the body and soul in this plastic period when, without this occasional excess, powers would atrophy or suffer arrest for want of use, or larger possibilities world not be realized without this regimen peculiar to nascent periods. This is treated more fully elsewhere.