The tribal or clannish spirit tends to manifest itself in many forms, but in all its varieties there is a common factor--that of isolation. At first sight we are tempted to regard the tribal spirit as part of a machinery evolved for the protection and survival of a primitive community, but to any one who has searched for conditions which will explain the origin of separate races of mankind, the conviction grows that the tribal spirit is an essential part of Nature's evolutionary machinery. It was in these isolated cradles of primitive mankind that Nature nursed and reared new races. When a breeder wishes to produce a new type of animal, or to preserve a 'sport', his first step is to isolate the group of animals with which he is to experiment. The isolated stock becomes the cradle in which he hopes to rear his new breed. The experimental breeder, in such instances, copies the conditions which rule in primitive human communities. Under modern civilization Nature's cradles have been smashed to atoms, but the tribal instincts which Nature intended for the propagation of new breeds of humanity have come down to modern man in undiminished force. Hence our present national and racial troubles. THE CONDITIONS OF TRIBAL DISINTEGRATION The tribal spirit, which maintains the unity of an elementary community, is efficient just so long as personal contact between its members is possible. If a tribal community becomes overgrown, so that mutual contact between its members is rendered impossible, then a manifestation of a different nature appears--that of disruption or swarming. The disintegrating tendency is just as much a part of Nature's evolutionary contrivance as is the isolating and unifying effect of the tribal spirit. For breeding purposes the group must be kept within certain bounds. Modern man has overcome the tendency to disruption on the part of massed communities by the invention of means of rapid intercommunication. The daily press, the hourly post, and a network of electric wires can bind a hundred millions of modern people into a sentient tribal web. THE ORIGIN OF RACE FEELING Small isolated communities are the cradles in which new tribal breeds of mankind are reared. But how do new races arise? If isolation were to be continued throughout long intervals of time we may justly infer that the physical and mental characters of a breed would become more and more emphasized until a stage of differentiation is reached which we must regard as racial. A racial spirit is merely the tribal spirit matured and consolidated. The manifestations which begin as tribal, end, in the course of time, by becoming racial. We cannot account for the differentiation of mankind into distinct races, nor the existence of many intermediate forms which link one human race to another, unless we postulate the existence in mankind of a deeply rooted tribal mechanism. TRANSFORMATION OF A TRIBAL INTO A NATIONAL SPIRIT