often occurs in bodily disease, secondly he may feel it during, or even throughout, sleep without dreaming at all, thirdly he may be awakened by it, and fourthly he may weave it into a dream. Even in the last instance it enters into the dream only in a disguised form, and it can be shown that this disguise depends on the nature not of the stimulus but of the rest of the dream. The same stimulus may appear in different dreams, even of the same person, under quite different forms, and analysis of the dream regularly shows that the form adopted is altogether determined by the character and motive of the dream. In short, the dream makes use of the somatic stimulus or not, according to its needs, and only when this fulfils certain requirements.
Having partly answered the question of how a dream is built we may take up the more difficult one of why it is built, or, more accurately put, the problems concerning the forces that go to make a dream. It is impossible to do this without first referring to Freud's views on psychical repression (Verdrängung) and unconscious mental processes; these views in themselves call for a detailed exposition which cannot here be given, so that this part of the present paper will be even more incomplete than the rest. Freud uses the term "conscious " to denote mental processes of which we are at a given moment conscious, "fore-conscious" (vorbewusste) to denote mental processes of which we can spontaneously and voluntarily become conscious (e.g., a memory out of one's mind for the moment, but which can readily be recalled), and "unconscious" to denote mental processes which the subject cannot spontaneously recall to consciousness, but which can be reproduced by employing special devices (e.g., hypnosis, psychoanalysis, etc.). He concludes that the force that has to be overcome in the act of making the last named processes conscious is the same as that which had previously opposed an obstacle to their becoming conscious, i. e., had repressed them into the unconscious. This force or resistance is a defensive mechanism which has kept from consciousness mental processes that were either primarily or secondarily (through association and transposition) of an inacceptable nature; in other words these processes are inassimilable in consciousness. Returning now to the subject of dreams, we have first to remark that Freud empirically found an intimate and legitimate relation between the degree of confusion and incomprehensibility present in a given dream and the difficulty the patient experienced in communicating the free associations leading to the dream thoughts. He therefore concluded that the distortion which had obviously occurred in the dream-making was related to the resistance that prevented the unconscious dream
