It is impossible to improve upon this pithy description of the salient facts, and terse explanation in terms of the hypothesis of natural selection. It may, perhaps, be urged that, on this hypothesis, the origin of the social state, through a biological association of individuals, probably neither preceded nor followed the development of a psychical bond arising from the sense of satisfaction and comfort afforded by social life, but that both originated _pari passu_. If the linkage was primarily instinctive, its intelligent continuance could only be effected through the pleasure social behaviour carried with it, and the discomfort of separation from the community. No instinctive acts would be persistently repeated, under the guidance of individual experience, if that experience proved bitter and not sweet. An animal with thwarted instincts is one with unsatisfied impulses; its biological and its psychological tendencies are alike unfulfilled. What Darwin saw and wished to enforce, however, was that the psychical link of conscious satisfaction was a necessary prerequisite of the continuance and further evolution of sociability; and that without the integrating bonds of sympathy any advance of social development was impossible. In two able and interesting articles in the _Nineteenth Century_ review,[109] on “Mutual Aid among Animals,” Prince Kropotkine gives a useful and sufficiently detailed summary of the chief facts concerning the social relationships which have been observed in the animal kingdom--including, perhaps, some rather apocryphal instances,--and combats Huxley’s statement[110] that, “beyond the limited and temporary relations of the family, the Hobbesian war of each against all is the normal state of existence” among animals and primitive men. “Life in societies,” says Prince Kropotkine, “is no exception in the animal world. It is the rule, the law of nature, and it reaches its fullest development with the higher vertebrates. Those species which live solitary, or in small families only, are relatively few, and their numbers are limited.”[111] “Life in societies enables the feeblest insects, the feeblest birds, and the feeblest mammals to resist, or to protect themselves from, the most terrible birds and beasts of prey; it permits longevity; it enables the species to rear its progeny with the least waste of energy, and to maintain its numbers, albeit with a very slow birth-rate; it enables the gregarious animals to migrate in search of new abodes. Therefore, while fully admitting that force, swiftness, protective colours, cunningness, and endurance to hunger and cold, which are mentioned by Darwin and Wallace, are so many qualities making the individual or the species the fittest under certain circumstances, we maintain that under _any_ circumstances sociability is the greatest advantage in the struggle for life.... The fittest are thus the most sociable animals, and sociability appears as the chief factor in