I have had occasion several times to allude to the practice of masturbation[38] by children, and will now proceed to give a more detailed description. I have previously alluded to masturbation as a manifestation of the detumescence impulse. Much more frequently, however, it occurs in those in whom the phenomena of the contrectation impulse have also been previously manifested. Sometimes it is a purely organic act, the individual masturbating in the entire absence of any imaginative sexual ideas; but at other times the imagination plays a notable part in the process, alike in children and in adults. When an imaginative idea is concerned in the process of masturbation, it is the idea of the object of the contrectation impulse; that is to say, the boy when masturbating thinks now of a girl, now, again (and this especially during the undifferentiated stage of the sexual impulse), of a boy, or in many cases of an adult; in the cases of girls who masturbate similar relationships obtain, Just as during youth masturbation is more commonly practised in association with than without imaginative sexual ideas, so also is it in the case of children; and even though imaginative activity may often be in abeyance when the masturbatory act is begun, during the progress of the act the imagination usually comes into operation. None the less, masturbation of a purely mechanical kind, in which the imagination plays no part, is comparatively more common during childhood than it is during youth. The peripheral processes of the detumescence impulse and the central processes of the contrectation impulse are not at this early age so intimately associated as they are later in life. Even when the contrectation impulse is already awakened, as usually happens before the detumescence impulse becomes active, when the detumescence impulse finally manifests itself, its gratification by means of masturbation without any imaginative activity is comparatively common in children. In such cases artificial stimulation of the genital organs is effected quite independently of the longing for intimate physical contact with and the embraces of another individual.