A full account of play will probably embrace all these theories, and though they were not formulated in his day, Froebel overlooked none, though he may have laid special stress on the preparation side. Yet another value of play emphasised by Professor Royce, viz. its enormous importance from the point of view of mental initiative, is strongly urged by Froebel. Professor Royce argues that "in the mere persistence of the playful child one has a factor whose value for mental initiative it is hard to overestimate." Without this "passionately persistent repetition," and without also the constant varying of apparently useless activities, the organism, says Professor Royce, "would remain the prey of the environment." To Froebel, as we have seen, the human being is the climax of animal evolution and the starting-point of psychical development. The lower animal, he maintained, as all will now agree, is hindered by his definite instincts, but the instincts or instinctive tendencies of the human being are so undefined that there is room for spontaneity, for new forms of conduct. Professor Royce says that "a general view of the place which beings with minds occupy in the physical world strongly suggests that their organisms may especially have significance as places for the initiation of more or less novel types of activity." And to Froebel the chief significance of play lies in this spontaneity. "Play is the highest phase of human development at this stage, because it is spontaneous expression of what is within produced by an inner necessity and impulse. Play is the most characteristic, most spiritual manifestation of man at this stage, and, at the same time, is typical of human life as a whole." These various theories seem to reinforce rather than to contradict each other, and it is more important to avoid running any to an extreme than to differentiate between them. In the case of recapitulation, we must certainly bear in mind Froebel's warning that the child "should be treated as having in himself the present, past and future." So, as Dr. Drummond says: "If we feel constrained to present him with a tent because Abraham lived in one, he no doubt enters into the spirit of the thing and accepts it joyfully. But he also annexes the ball of string and the coffee canister to fit up telephonic communication with the nursery." He may play robbers and hide and seek because he has reached a "hunting and capture" stage, but the physiologist points out that violent exercise is a necessity for his circulation and nutrition, and to practise swift flight to safety is useful even in modern times.[11] Gardening may take us back to an agricultural stage, but digging is most useful as a muscular exercise, and "watering" is scientific experiment and adds to the feeling of power, while the flowers themselves appeal to the aesthetic side of the sense-play, which is not limited to any age, though conspicuous so soon.