The factor in societal evolution corresponding to heredity in organic evolution is tradition; and the agency of transmission is the nervous system by way of its various "senses" rather than the germ-plasm. The organs of transmission are the eye, ear, tongue, etc., and not those of sex. The term tradition, like variation and selection, is taken in the broad sense. Variation in nature causes the offspring to differ from the parents and from one another; variation in the folkways causes those of one period (or place) to differ from their predecessors and to some extent among themselves. It is the vital fact at the bottom of change. Heredity in nature causes the offspring to resemble or repeat the present type; tradition in societal evolution causes the mores of one period to repeat those of the preceding period. Each is a stringent conservator. Variation means diversity; heredity and tradition mean the preservation of type. If there were no force of heredity or tradition, there could be no system or classification of natural or of societal forms; the creation hypothesis would be the only tenable one, for there could be no basis for a theory of descent. If there were no variation, all of nature and all human institutions would show a monotony as of the desert sand. Heredity and tradition allow respectively of the accumulation of organic or societal variations through repeated selection, extending over generations, in this or that direction. In short, what one can say of the general effects of heredity in the organic realm he can say of tradition in the field of the folkways. That the transmission is in the one case by way of the sex organs and the germ-plasm, and in the other through the action of the vocal cords, the auditory nerves, etc., would seem to be of small moment in comparison with the essential identity in the functions discharged.