Analogous phenomena may be witnessed in the animal world also, in connexion with the masturbatory acts of monkeys, bulls, and stallions. When a stallion kicks its genital organs again and again with its hind-foot, and repeats the action until ejaculation ensues, we are hardly justified in assuming that the animal has the idea of a mare before its mind. We must rather suppose that we have to do with a local physical stimulus, to which the stallion reacts in the manner above described. The other component, also, of the sexual impulse, the contrectation-impulse, manifests itself, occasionally, at any rate, in isolation. Certain boys, long before the appearance of any signs of the puberal development, are impelled towards physical contact with members of the other sex, to kiss them, to think of them, although these boys may exhibit no tendency whatever to masturbate, or to manipulate their genital organs. It often happens, indeed, that such a boy is himself greatly astonished to find, some day, that these ideas are reflected to the genital organs, giving rise to erection; or, when he is embracing a girl, to experience erection and ejaculation. In the sexually mature normal man, the detumescence-impulse and the contrectation-impulse act in unison, and hence he is impelled towards intimate contact with the woman, and is ultimately driven to effect detumescence by the practice of coitus. Nevertheless, we must hold fast to the idea that in the normal adult man the sexual processes may also be theoretically analysed into these two components. This is true also of woman, in whom the processes in the genital organs are equally separable from those which impel to contact with a member of the other sex. But in woman, the processes in the genital organs do not culminate in the ejection of the reproductive cells, that is, of the ovum, but, as we have seen, in the ejaculation of indifferent secretions. In the woman, also, the detumescence impulse is occasionally met with in isolation--for example, in many female idiots. In the animal world, too, we encounter it as an isolated phenomenon. Certain mares, when rutting, rub their hind quarters against some object in their stalls. The contrectation-impulse may also manifest itself in isolation in woman. It is then directed towards the male, but is not in any way associated with the wish for a definite sexual act. Most commonly, however, in woman also the two components of the sexual impulse are united, and from this union results the impulsion towards coitus. But to this extent the conditions in woman are apt to differ from those in man, inasmuch as, in the former, voluptuous sensations are more often in abeyance; or in woman voluptuous pleasure may not arise during coitus, but may be produced in some other way, as, for instance, by a masturbatory act.