(_c_) The partial desires which usually appear in contrasting pairs play a very prominent rôle among the symptom-creators in the psychoneuroses. We have learned to know them as carriers of new sexual aims, such as peeping mania, exhibitionism, and the actively and passively formed impulses of cruelty. The contribution of the last is indispensable for the understanding of the morbid nature of the symptoms; it almost regularly controls some portion of the social behavior of the patient. The transformation of love into hatred, of tenderness into hostility, which is characteristic of a large number of neurotic cases and apparently of all cases of paranoia, takes place by means of the union of cruelty with the libido. The interest in these deductions will be more heightened by certain peculiarities of the diagnosis of facts. Alpha. There is nothing in the unconscious streams of thought of the neuroses which would correspond to an inclination towards fetichism; a circumstance which throws light on the psychological peculiarity of this well understood perversion. Beta. Wherever any such impulse is found in the unconscious which can be paired with a contrasting one, it can regularly be demonstrated that the latter, too, is effective. Every active perversion is here accompanied by its passive counterpart. He who in the unconscious is an exhibitionist is at the same time a voyeur, he who suffers from sadistic feelings as a result of repression will also show another reinforcement of the symptoms from the source of masochistic tendencies. The perfect concurrence with the behavior of the corresponding positive perversions is certainly very noteworthy. In the picture of the disease, however, the preponderant rôle is played by either one or the other of the opposing tendencies. Gamma. In a pronounced case of psychoneurosis we seldom find the development of one single perverted impulse; usually there are many and regularly there are traces of all perversions. The individual impulse, however, on account of its intensity, is independent of the development of the others, but the study of the positive perversions gives us the accurate counterpart to it. PARTIAL IMPULSES AND EROGENOUS ZONES