"Dr. James Jackson, of Boston, allowed the children four hours schooling in winter and five in summer, but only one hour at a time; and heartily expressed his detestation of giving young children lessons to learn at home. "Dr. S.G. Howe, reasoning elaborately on the whole subject, said that children under eight years of age should never be confined more than half an hour at a time; by following which rule, with long recesses, they can study four hours daily. Children between eight and fourteen should not be confined more than three-quarters of an hour at a time, having the last quarter of each hour for exercise on the play-ground. "Indeed, the one thing about which doctors do _not_ disagree is the destructive effect of premature or excessive mental labor. I can quote you medical authority for and against every maxim of dietetics beyond the very simplest; but I defy you to find one man who ever begged, borrowed, or stole the title of M.D., and yet abused those two honorary letters by asserting under their cover that a child could safely study as much as a man, or that a man could safely study more than six hours a day." "The worst danger of it is that the moral is written at the end of the fable, not at the beginning. The organization in youth is so dangerously elastic that the result of these intellectual excesses is not seen until years after. When some young girl incurs spinal disease from some slight fall, which she ought not to have felt for an hour, or some business man breaks down in the prime of his years from some trifling over-anxiety, which should have left no trace behind, the popular verdict may be 'Mysterious Providence;' but the wiser observer sees the retribution for the folly of those misspent days which enfeebled the childish constitution instead of ripening it. One of the most striking passages in the report of Dr. Ray, before mentioned, is that in which he explains that, 'though study at school is rarely the immediate cause of insanity, it is the most frequent of its ulterior causes, except hereditary tendencies.' _It diminishes the conservative power of the animal economy to such a degree that attacks of disease which otherwise would have passed off safely destroy life almost before danger is anticipated_."