The first care in muscle culture must be to secure abundance and diversity of kinetic energy. “Here, as everywhere, the rule holds that powers themselves must be unfolded before the ability to check or even use them can develop” (1: vol. i, p. 161). The vigorous spontaneity of sporadic movements in young children should be cherished instead of suppressed. The coördination of these purposeless activities into higher compounds of habits should come only slowly and gradually, or else it will cause either atrophy or disease of motor function. The natural evolutionary course of muscular development has been from the fundamental to the accessory; and early childhood is the period for the development of larger basal muscles. Any fine work requiring accuracy, taxing the tiny accessory muscles, either of the eyes, of the tongue, or of the fingers should not be exacted. Training of the accessory muscles ought to come between the ages of eight and twelve. This is preëminently the period for drill, for mechanization. Puberty is the stage of ill-balanced transition. The motor coördinations are lost for a moment, all the ways of awkwardness, mannerisms, and semi-imperative acts manifest themselves as a result. “This is again the age of the basal--e. g., hill-climbing muscles of leg and back and shoulder work, and of the yet more fundamental heart, lung, and chest muscles” (1: vol. i, p. 165). As during early childhood, now the danger is overemphasis upon the activities of accessory muscles and overprecision. Now, again, book-studies, class-lessons may become an evil. They constitute “not a liberal, power-generating, but a highly and prematurely specialized, narrowing and weakening education, unless offset by safeguards better than any system of gymnastics, which is at best artificial and exaggerated” (1: vol. i, p. 165). For Dr. Hall, play presents the ideal type of exercise; he, like Froebel, spares no words of praise for its merits. According to him, in play we unconsciously rehearse the motor experience of the race. The motor habits won by the long history of toil and pain, elaborated in the life-and-death struggle for existence, now reappear in us by impulse, as spontaneity and joy. And “pleasure is always exactly proportional to the directness and force of the current of heredity” (1: vol. i, p. 206). It is, therefore, his opinion that we should direct the exercise of the young to these old basal activities handed down from the distant past, which have built up the intellect and character as well as the physique of the race, rather than insist upon those arbitrary systems and methods invented to form a symmetrical body according to our ideas. He thinks that “education perhaps should really begin with directing childish sports aright” (1: vol. i, p. 231).