It must be confessed that the testimony of anthropologists on the difference in variability of men and women is to be accepted with great caution. As a class they have gone on the assumption that woman is an inferior creation, and have almost totally neglected to distinguish between the congenital characters of woman and those acquired as the result of a totally different relation to society on the part of women and men. They have also failed to appreciate the fact that differences from man are not necessarily points of inferiority, but adaptations to different and specialized modes of functioning. But, whatever may be the final interpretation of details, I think the evidence is sufficient to establish the following main propositions: Man consumes energy more rapidly; woman is more conservative of it. The structural variability of man is mainly toward motion; woman's variational tendency is not toward motion, but toward reproduction. Man is fitted for feats of strength and bursts of energy; woman has more stability and endurance. While woman remains nearer to the infantile type, man approaches more to the senile. The extreme variational tendency of man expresses itself in a larger percentage of genius, insanity, and idiocy; woman remains more nearly normal. The fact that society is composed of two sexes, numerically almost equal, but differing in organic and social habits, is too significant to remain without influence on the structural and occupational sides of human life, and in the following chapters we shall note some of the influences of sex, and of the differences in bodily habit of men and women, on social forms and activities. SEX AND PRIMITIVE SOCIAL CONTROL The greater strength and restlessness of man and the more stationary condition of woman have a striking social expression in the fact that the earliest groupings of population were about the females rather than the males. While at a disadvantage in point of force when compared with the male, the female has enjoyed a negative superiority in the fact that her sexual appetite was not so sharp as that of the male. Primitive man, when he desired a mate, sought her. The female was more passive and stationary. She exercised the right of choice, and had the power to transfer her choice more arbitrarily than has usually been recognized; but the need of protection and assistance in providing for offspring inclined her to a permanent union, and doubtless natural selection favored the groups in which parents co-operated in caring for the offspring. But assuming a relation permanent enough to be called marriage, the man was still, as compared with the woman, unsettled and unsocial. He secured food by violence or cunning, and hunting and fighting were fit expressions of his somatic habit.