in different individuals. In the typical, functionally perfect woman, on the other hand, the body-hair, except in the restricted regions mentioned, remains as fine and as colorless as in the child.
This hair development is not associated with sexual ripening in a chance way, but is controlled by the fundamental sex glands. These glands not only produce the germ cells (the egg and the spermatozoön) whose union creates the life of a new individual; they secrete also, into the blood stream, hormones, i. e., substances which profoundly influence the growth of various parts of the organism. The internal secretions of the male glands produce those changes in the vocal organs which are indicated by the voice becoming heavier and lower; stimulate the growth of the body-hair in the manner above indicated; and undoubtedly promote those structural and functional changes which are evidenced in the tendencies of feeling and action distinctive of the male. If the glands are removed in infancy, these changes do not occur. The secretions of the ovaries, on the other hand, seem to inhibit the growth of body-hair, to accelerate those structural changes in the muscles, glands and skeleton which differentiate the woman from the man, and promote those functional modifications which make the feelings and emotions of each sex a sealed book to the other.
It may be said of the important races of man-
