ABSTRACT
I WISH TO START from the standpoint that the two factors of heredity and environment are not mutually exclusive and that both influence the development of the child. There is in the developing child some internal force, of the same nature as that which gives the foetus a working system of circulation and a breathing system ready to function immediately after birth. Actually, these systems go on developing after birth, and their elaboration and development are parallel to the phenomenon of development of the nervous system. The fact that this is a process of maturation explains in great part the consistency of the development, it is a constantly moving scale which leads us from the newly-born to the older child.
