But play is more than a general exercise of the bodily organs. It is a preparation for the specialized activities of the serious part of life. The animal meets in play things which behave very much like those things which it has to obtain for food. So it learns to obtain food at a time when food is not yet needed. It learns to defend itself when no one yet attacks it. The biological significance of the play movements obviously consists in this preparation for the special activities of life. Those animals which do not possess a strong tendency to play are thus at a disadvantage in the struggle for life, because they miss the opportunity for preparation. Serious activity and play accompany man and animal all through life; but the proportion changes. The young are taken care of by their parents, and play may therefore prevail. With maturity this changes, and less time is left for play. All these movements of self-preservation and of play are natural inherited responses of the organism to its environment. Many of them do not appear at the very entrance into life, but at different stages of age and growth. They are the raw material from which all conduct is derived and built up. Their nervous conditions are the nervous processes in the reflex arches of the subcortical nerve centers. From the points of sensory stimulation, the nervous processes are carried into definite muscle groups so that definite movements occur. These movements are called _reflexes_ or _instincts_ according as they are rather simple or more complex. Both reflexes and instincts are inherited movements following in direct response upon sensory stimulation. QUESTIONS 111. What is the ultimate end of every nervous process? 112. What are typical movements of self-preservation? 113. What are typical movements of play? 114. Is play more than a general exercise of the body? 115. Are all inherited movements possible immediately after birth? 116. What is the difference between reflexes and instincts? § 13. THOUGHT AND MOVEMENT