b) _Touch as the physiological basis of social contact._--According to the spatial conception the closest contacts possible are those of touch. The physical proximity involved in tactile sensations is, however, but the symbol of the intensity of the reactions to contact. Desire and aversion for contacts, as Crawley shows in his selection, arise in the most intimate relations of human life. Love and hate, longing and disgust, sympathy and hostility increase in intensity with intimacy of association. It is a current sociological fallacy that closeness of contact results only in the growth of good will. The fact is, that with increasing contact either attraction or repulsion may be the outcome, depending upon the situation and upon factors not yet fully analyzed. Peculiar conditions of contact, as its prolonged duration, its frequent repetition, just as in the case of isolation from normal association, may lead to the inversion of the original impulses and sentiments of affection and antipathy.[117] c) _Contacts with the "in-group" and with the "out-group."_--The conception of the we-group in terms of distance is that of a group in which the solidarity of units is so complete that the movements and sentiments of all are completely regulated with reference to their interests and behavior as a group. This control by the in-group over its members makes for solidity and impenetrability in its relations with the out-group. Sumner in his _Folkways_ indicates how internal sympathetic contacts and group egotism result in double standards of behavior: good-will and co-operation within the members of the in-group, hostility and suspicion toward the out-group and its members. The essential point is perhaps best brought out by Shaler in his distinction between sympathetic and categoric contacts. He describes the transition from contacts of the out-group to those of the in-group, or from remote to intimate relations. From a distance, a person has the characteristics of his group, upon close acquaintance he reveals his individuality. d) _Historical continuity and mobility._--Historical continuity, which maintains the identity of the present with the past, implies the existence of a body of tradition which is transmitted from the older to the younger generations. Through the medium of tradition, including in that term all the learning, science, literature, and practical arts, not to speak of the great body of oral tradition which is after all a larger part of life than we imagine, the historical and cultural life is maintained. This is the meaning of the long period of childhood in man during which the younger generation is living under the care and protection of the older. When, for any reason, this contact of the younger with the older generation is interrupted--as is true in the case of immigrants--a very definite cultural deterioration frequently ensues.