We are now in the best position to complete our psychological construction, which has been interrupted by the introduction of the two systems, Unc. and Forec. We have still, however, ample reason for giving further consideration to the wish as the sole psychic motive power in the dream. We have explained that the reason why the dream is in every case a wish realization is because it is a product of the Unc., which knows no other aim in its activity but the fulfillment of wishes, and which has no other forces at its disposal but wish-feelings. If we avail ourselves for a moment longer of the right to elaborate from the dream interpretation such far-reaching psychological speculations, we are in duty bound to demonstrate that we are thereby bringing the dream into a relationship which may also comprise other psychic structures. If there exists a system of the Unc.--or something sufficiently analogous to it for the purpose of our discussion--the dream cannot be its sole manifestation; every dream may be a wish-fulfillment, but there must be other forms of abnormal wish-fulfillment beside this of dreams. Indeed, the theory of all psychoneurotic symptoms culminates in the proposition _that they too must be taken as wish-fulfillments of the unconscious_. Our explanation makes the dream only the first member of a group most important for the psychiatrist, an understanding of which means the solution of the purely psychological part of the psychiatric problem. But other members of this group of wish-fulfillments, _e.g._, the hysterical symptoms, evince one essential quality which I have so far failed to find in the dream. Thus, from the investigations frequently referred to in this treatise, I know that the formation of an hysterical symptom necessitates the combination of both streams of our psychic life. The symptom is not merely the expression of a realized unconscious wish, but it must be joined by another wish from the foreconscious which is fulfilled by the same symptom; so that the symptom is at least doubly determined, once by each one of the conflicting systems. Just as in the dream, there is no limit to further over-determination. The determination not derived from the Unc. is, as far as I can see, invariably a stream of thought in reaction against the unconscious wish, _e.g._, a self-punishment. Hence I may say, in general, that _an hysterical symptom originates only where two contrasting wish-fulfillments, having their source in different psychic systems, are able to combine in one expression_. (Compare my latest formulation of the origin of the hysterical symptoms in a treatise published by the _Zeitschrift fuer Sexualwissenschaft_, by Hirschfeld and others, 1908). Examples on this point would prove of little value, as nothing but a complete unveiling of the complication in question would carry conviction. I therefore content myself with the mere assertion, and will cite an example, not for conviction but for explication. The