A DIFFERENCE IN THE METABOLISM OF THE SEXES 6 1
enccphalon simply mediate the perception which stimulates the vaso-motor system. The superior physiological irritability of woman, whether we call it sensibility, feeling, emotionality or affectability, is due to the fact of the larger development of her abdominal zone, and the activity of the physiological changes located there in connection with the process of repro- duction.
This physiological predisposition of woman to feeling expres- ses itself primarily in love of offspring, and secondarily in ties of blood. Subsequent to the conversion of her surplus of energy into offspring there follows a period in which her surplus energy is converted into milk for the sustentation of the offspring, and the time during which the child draws its life from the breast of the mother is a moment of supreme importance for the development of the race, since it is in connection with this quasi-physiological association that the first altruistic sentiments are knit. The first social unit is not the family but the mother and her group of children, and the tribe is primarily an aggregation of those related by blood to a group of females.
Both social feeling and social organization are thus primarily feminine in origin functions of the anabolism of woman. But natural selection operates still further in favoring both the off- spring and the community where the male is associated in a supplementary way with the female in the expression of social feeling and the extension of social activities. Thus in the human species those races have prevailed in which in conse- quence of a monogamous system of marriage the providence of both parents is assured to the offspring, resulting in better nutri- tion and somatic and psychical training; and those nations have prevailed in which the katabolic energies of man have extended into a complicated political system based on territory, the tribal organization based on descent through females. But it is impossi- ble that humanitarian sentiments should have been developed except as a supervention upon maternal affection, and impossible that political organization should have developed except as a supervention upon association based on tics of blood.
