Is there—at any rate in the higher forms of these colonies—a social instinct? Solidarity and reciprocity can indeed be perceived, in an objective, material way, in the form of adherence, and vascular communication; but nothing proves that there is anything more than an _organic_ solidarity and reciprocity. Perhaps, in circumstances such as the nautical manœuvres just mentioned, in which a general obedience to one directing individual has been ascertained, there is a momentary consent—a certain unity of representation. To be accurate, the terms individual and community are diverted from their ordinary acceptation and used in an equivocal sense. Our notion of the individual is that of an organised whole living independently by itself: this no longer corresponds to the present case. Our notion of a community is an assemblage of individuals, and as these are, in the case under consideration, of a peculiar nature, it might thus be contended with equal force that these aggregates deserve, or that they do not deserve, the name of animal communities: it is a question of the point of view. On the one hand, one may regard the hydractinia or the siphonophora as a complex individual whose organs are the fishing, the piloting, the reproductive, etc., individuals. On the other hand, it may be maintained that the food-providers, pilots, etc., are true individuals whose aggregation forms a society. In short, it is an undifferentiated state, in which individuals and community are hardly to be distinguished from one another, and are only two different aspects of the same whole. The social instinct, also, if existing at all, is not yet differentiated from the conservative instinct under its simplest forms—the search for food, defence, attack. In fact, the two coincide. This stage has nothing more to teach us. Let us now pass on to social forms whose psychology is clearer. II. These are the societies founded on reproduction—domestic societies, or families, under their various forms. I prefer to begin with these rather than with the gregarious state; first, on account of their universality; then because they are the first to appear in chronological order. Common opinion finds in them the first manifestation of the social sentiments, their origin, their source, and their moment of entry into the world. I reject this view in order to adopt that which connects the social instinct with the gregarious state. If we take, one after another, the conditions of every aggregate founded on reproduction, we shall find three stages: that of sexual approach, that of maternal love, and lastly, but in the case of animals only exceptionally, paternal love. The social instinct—_i.e._, the more or less vague consciousness of at least a temporary solidarity and reciprocity—does not, as we shall see, make its appearance at any of these stages.