In its various forms, so far as we know them, Love seems always to have a deep significance and a most practical importance to us little mortals. In one form, as the mere semi-conscious Sex-love, which runs through creation and is common to the lowest animals and plants, it appears as a kind of organic basis for the unity of all creatures; in another, as the love of the mother for her offspring—which may also be termed a passion—it seems to pledge itself to the care and guardianship of the future race; in another, as the marriage of man and woman, it becomes the very foundation of human society. And so we can hardly believe that in its homogenic form, with which we are here concerned, it has not also a deep significance, and social uses and functions which will become clearer to us, the more we study it.