Plastic matter, in transmitting its organisation, takes various courses which it is the part of natural history to describe. Even after reproduction has become sexual, it will offer no basis for love if it does not require a union of the two parent bodies. Did germinal substances, unconsciously diffused, meet by chance in the external medium and unite there, it is obvious that whatever obsessions or pleasures maturity might bring they would not have the quality which men call love. But when an individual of the opposite sex must be met with, recognised, and pursued, and must prove responsive, then each is haunted by the possible other. Each feels in a generic way the presence and attraction of his fellows; he vibrates to their touch, he dreams of their image, he is restless and wistful if alone. When the vague need that solicits him is met by the presence of a possible mate it is extraordinarily kindled. Then, if it reaches fruition, it subsides immediately, and after an interval, perhaps, of stupor and vital recuperation, the animal regains his independence, his peace, and his impartial curiosity. You might think him on the way to becoming intelligent; but the renewed nutrition and cravings of the sexual machinery soon engross his attention again; all his sprightly indifference vanishes before nature’s categorical imperative. That fierce and turbid pleasure, by which his obedience is rewarded, hastens his dissolution; every day the ensuing lassitude and emptiness give him a clearer premonition of death. It is not figuratively only that his soul has passed into his offspring. The vocation to produce them was a chief part of his being, and when that function is sufficiently fulfilled he is superfluous in the world and becomes partly superfluous even to himself. The confines of his dream are narrowed. He moves apathetically and dies forlorn.