Undoubtedly, a great portion of the mental and nervous disorder commonly attributed to heredity is largely caused or aggravated by imitation and by vicious training of children. Schopenhauer says that the normal man is two-thirds will and one-third intellect—in other words, two-thirds made by education and one-third by inheritance. The intellect is often trained so as to enfeeble the will as well as to hinder the development of the physical man. Self-culture may so degenerate into self-indulgence as to destroy individuality and force; and mental health, as a rule, depends upon bodily health and the exercise of self-control. In the uncivilized and half-civilized races of the world insanity is rare; in the early civilizations the insane perished from neglect, were hanged and burned, starved and died in famine and pestilence, and fell among the foremost in war. Some of the tribes of North American Indians shoot the insane, considering them possessed of evil spirits, while their white neighbors keep them in chains and squalor. Civilization brings better food, clothing, and shelter, and less danger from war, famine, and pestilence than savage or mediæval times. In the struggle for existence, however, physical strength no longer wholly wins the day, but also those faculties that involve great mental and bodily strain in mines, factories, crowded tenements, counting-rooms, offices; in the eager, excited over-study for prizes or rank in overheated, badly-ventilated schools, and, indeed, in every walk of life. People with marked neuroses, who would have gone to the wall a couple of centuries ago from want of physical strength, now support themselves by indoor light work, marry, and reproduce their kind. Minute division of labor involves monotonous toil and increases the impairment of the body's resistance to mental and nervous strain, and abuse of the nerve-stimulants tea, coffee, tobacco, or, worst of all, alcohol and narcotics, add to the evil. Degeneration due to the reproduction of poor stock is intensified by intermarriage. Luxury, idleness, excesses, syphilis, debility, drunkenness, poverty, disease, and overwork produce vitiated constitutions in which varying types of insanity appear in various nations and climates, but, so far as is known at present, not in very different degree under similar conditions. One of the great problems of the day is whether the many conditions incompatible with health in our crowded populations can be overcome so as to prevent the degeneration going on thereby.