"Unaccommodated man" was, to begin with, in relations more hostile than friendly. The struggle for food was so serious a fact, and predaceousness to such a degree the habit of life, that a suspicious, hostile, and hateful state of mind was the rule, with exceptions only in the cases where truce, association, and alliance had come about in the course of experience. This was still the state of affairs in so advanced a stage of development as the Indian society of North America, where a tribe was in a state of war with every tribe with which it had not made a treaty of peace; and it is perhaps true, generally speaking, of men today, that they regard others with a degree of distrust and aversion until they have proved themselves good fellows. What, indeed, would be the fate of a man on the streets of a city if he did otherwise? There has, nevertheless, grown up an intimate relation between man and certain portions of his environment; and this includes, not only his wife and children, his dog and his blood-brother, but, with lessening intensity, the members of his clan, tribe, and nation. These become, psychologically speaking, a portion of himself, and stand with him against the world at large. From the standpoint here outlined, prejudice or its analogue is the starting-point, and our question becomes one of the determination of the steps of the process by which man mentally allied with himself certain portions of his environment to the exclusion of others. If we look for an explanation of the hostility which a group feels for another group, and of the sympathy which its members feel for one another, we may first of all inquire whether there are any conditions arising in the course of the biological development of a species which, aside from social activities, lead to a predilection for those of one's own kind and a prejudice against different groups. And we do, in fact, find such conditions. The earliest movements of animal life involve, in the rejection of stimulations vitally bad, an attitude which is the analogue of prejudice. On the principle of chemiotaxis, the micro-organism will approach a particle of food placed in the water and shun a particle of poison; and its movements are similarly controlled by heat, light, electricity, and other tropic forces.[159] The development of animal life from this point upward consists in the growth of structure and organs of sense adapted to discriminate between different stimulations, to choose between the beneficial and prejudicial, and to obtain in this way a more complete control of the environment. Passing over the lower forms of animal life, we find in the human type the power of attention, memory, and comparison highly developed, so that an estimate is put on stimulations and situations correspondent with the bearing of stimulations or situations of this type on welfare in the past. The choice and rejection involved in this process are accompanied by organic changes (felt as emotions) designed