Now, when we remember that the method of intelligence is to profit by chance experience, while the method of reason is, with foresight and intention, to adapt means to ends, we shall see that to move a straw even a quarter of an inch, or to make a bridge with particles of mould, would require rational and not merely intelligent powers. Chance experience would not supply the necessary data to be utilized by intelligence when repetition had established an association in the conscious situation. Granting that the ants were intelligent but not rational, they could not be expected to overcome the difficulties, simple as they seem to us, which Lord Avebury placed in their path. Had they been overcome the fact would be more difficult to explain than the use of a stone tool by the sand wasp, since this could more readily be hit upon by chance experience. And what these valuable experiments, of which kind more are needed, seem to show is, that the ant, probably the most intelligent of all insects, has no claim to be regarded as a rational being. IV.--ANIMAL TRADITION In that interaction between instinct and intelligence which, when further detailed work has sifted and purified our knowledge of the psychology of animal communities, may prove sufficient to account for the well-established facts, animal tradition will probably have to be recognized as of no little importance. When a newly emerging ant or bee, or a young bird or mammal is born into a community where certain modes of behaviour are already in full swing, an imitative tendency of the follow-my-leader type may lead it to fall in line with the traditional habits. It is said that young ants follow the older workers about the nest, and are “trained to a knowledge of domestic duties, especially in the case of larvæ.” On the other hand, we have seen that, in certain observed cases, the queen ant is the solitary starting-point of a new community, and that the division of labour follows with the increasing numbers of the newly formed social group; so that, in such cases, whatever part tradition may play in the later phases of social life, it cannot afford a sufficient account of the division of labour in the earlier history of the community. We need, however, fuller information concerning the continued life-history of such communities under natural conditions, and as to how far they remain self-contained without any incorporation of older members from adjoining nests. In the case of bees, where the old queen departs with a swarm, there may be greater continuity of tradition. But how far this is a necessary factor in social development is at present a matter of conjecture. In the herd of mammals and the flock of birds, and in all the family and social life in these classes of animals, the example of elders, without any imitation of the higher reflective type, can scarcely be without its influence on the behaviour of the young which, one would suppose,