On what grounds, then, can we decide that certain processes are of a sexual nature? In many instances, only the subsequent development will show that one process was sexual, another non-sexual. If one day a boy, embracing, as often before, his girl friend, has an erection, and then perhaps endeavours to draw her towards him so that her body presses against his genital organs, or even has an ejaculation with a voluptuous sensation, we may assume the influence of a contrectation impulse, which has existed for some time, but only now has for the first time been localised in the peripheral genital organs. On the other hand, if in the same boy when he hugs his mother no peripheral sexual manifestations occur, either now or subsequently, we must assume that in the earlier embraces of his mother there was no sexual element. But no such simple solution of the difficulty is really possible. It may happen that in the case of feelings originally sexual their further development is inhibited. A boy might experience sexual sentiments towards his mother; but it is very probable that in such a case convention, education, and perhaps also the very frequent association with his mother, would repress the growth of these sentiments. This criticism is a sound one, and in my opinion the materials are lacking to enable us to overcome its force. For why should certain processes occurring in childhood--for example, a boy's impulse to caress his mother--be regarded as non-sexual; and yet the same processes subsequently be regarded as sexual, merely because they ultimately become associated with the phenomena of detumescence? Take the case of a boy seven years of age; he loves and cuddles his mother; he is drawn also to a girl friend of the same age as himself, and kisses her with equal pleasure. The boy grows older, and after some years begins to have definite erections when he embraces and kisses his friend; but nothing of the kind occurs when he embraces and kisses his mother. Now, have we any right to assert, simply owing to the subsequent appearance of these peripheral manifestations in the one case and not in the other, that originally, when between the boy's inclination towards his girl friend and his inclination towards his mother no clear distinction could be drawn, the former was sexual, the latter non-sexual in nature?