tion of the dream thoughts into the dream proper takes place according to certain well-determined psychological laws, and for very precise reasons. The core of Freud's theory, and the most original part of his contribution to the subject, resides in his tracing the cause of this distortion to a "censor" which interposes an obstruction to the becoming conscious of unconscious psychical processes. This conception, he arrived at from the analysis of various abnormal psychical manifestations, psycho-neurotic symptoms, which he found to be constructed on a plan fully analogous to that of dreams. It may be remarked at this point that, quite apart from any views as to the cause of the distortion, the nature and functions of the dream thoughts and other problems, the fact itself of the distortion is certain, and cannot be doubted by any one who carefully observes a few dreams. That, for instance, the vision of a strange room in a dream is a distorted presentation of several rooms that have been actually seen, from each of which various individual features have been abstracted and fused together so as to present a new and therefore strange room, is the kind of observation that can easily be verified. Before considering, therefore, the nature of the latent content it will be well shortly to describe the distorting mechanisms by means of which it becomes transformed into the manifest content.
A dream is not, as it appears to be, a confused and haphazard congeries of mental phenomena, but a distorted and disguised expression of highly significant psychical processes that have a very evident meaning, although in order to appreciate this meaning it is first necessary to translate the manifest content of the dream into its latent content, just as a hieroglyphic script yields its meaning only after it has been interpreted. The mechanisms by means of which the manifest content has been formed from the underlying dream thoughts may be grouped under four headings.
The first of these is called Condensation (Verdichtung). Every element of the manifest content represents several dream thoughts; it is, as Freud puts it, "over-determined" (überdeterminiert). Thus the material obtained by analysis of a dream is far richer and more extensive than the manifest content, and may exceed this in amount by ten or twenty times. Of all the mechanisms it is the easiest to observe, and to it is mainly due the sense of foreignness that dreams give us, for it is a process with which our waking thought is not familiar. The representation in the manifest content of the extensive material comprising the latent content is brought about by a true condensation, rarely by the mere omission of part of the latent content. The condensation is effected in several ways. A figure in a dream may be constituted by the
