1. Sexual approach results from one particular instinct; it unites two individuals only: can we consider it as the embryo of a society? “Around sexuality are co-ordinated the altruistic instincts of which the animal is capable.” This formula of Littré’s needs defining with more precision. First, in the immense majority of cases the connection is not lasting; the blind instinct satisfies itself, and all is over. Higher up there are more permanent forms, such as polygamy and polyandry; but these small communities founded on sex-attraction are closed, and have no power of radiation or extension, no future. Higher still we find monogamy, as among wolves, many birds, etc.; but the monogamic aggregate is still more of a close corporation than the others. Let us note, in passing, that these two forms, polygamy and monogamy, are distributed through the animal world in an apparently fortuitous manner, having no relation to the intellectual development—as, for instance, the monogamy of the stork and the polygamy of the monkey. Finally, this first stage yields us no result, tending rather towards social restriction than social extension. 2. Maternal love is of much greater importance. In domestic societies it is the universal and permanent element, the vital bond. This emotion is so widespread, so well known, we might say so trite, that it seems to involve no mystery, and yet, if we descend into animal psychology, we find nothing more enigmatical. The development of sympathy and intelligence partly explains it in the human species and the higher animals; but in the lower orders the difficulty becomes extreme. Yet it shows itself among the annelids, the crustacea, the mollusca, and even the echinoderms, which carry their eggs about adhering to their bodies. Frequently it shows itself as a feeling which, though vague, is tenacious, devoted, heroic. We do not indicate all the difficulties of the question, as for instance: How can an insect take such care of its eggs when it cannot recognise its own form in a creature which in nowise resembles itself, and has not even a living form?[169] ----- Footnote 169: For a detailed study of this question see Espinas, _Les Sociétés Animales_ (2nd ed.), pp. 334 _et seq._, 411 _et seq._, 444 _et seq._ -----