The period of childhood which precedes puberty and lasts about three years is one in which growth, both physical and mental, is slower than at any time until near complete maturity. The child has reached a point of stability, and of almost complete adaptation to its environment. The dawn to the full development of the function of reproduction occupies four to five years, and during this period, and coincident with the formation of the secondary bodily sexual characters, there is a complete mental revolution peculiar to each sex.