I must assume that the sensory surface of consciousness which is turned to the preconscious is rendered far more unexcitable by sleep than the surface turned toward the P-system. The giving up of interest in the nocturnal thought-process is, of course, an appropriate procedure. Nothing is to happen in thought; the preconscious wants to sleep. But once the dream becomes perception, it is capable of exciting consciousness through the qualities now gained. The sensory excitation performs what is in fact its function; namely, it directs a part of the cathectic energy available in the Pcs to the exciting cause in the form of attention. We must therefore admit that the dream always has a waking effect- that is, it calls into activity part of the quiescent energy of the Pcs. Under the influence of this energy, it now undergoes the process which we have described as secondary elaboration with a view to coherence and comprehensibility. This means that the dream is treated by this energy like any other perception-content; it is subjected to the same anticipatory ideas as far, at least, as the material allows. As far as this third part of the dream- process has any direction, this is once more progressive.

To avoid misunderstanding, it will not be amiss to say a few words as to the temporal characteristics of these dream- processes. In a very interesting discussion, evidently suggested by Maury's puzzling guillotine dream, Goblot tries to demonstrate that a dream takes up no other time than the transition period between sleeping and waking. The process of waking up requires time; during this time the dream occurs. It is supposed that the final picture of the dream is so vivid that it forces the dreamer to wake; in reality it is so vivid only because when it appears the dreamer is already very near waking. "Un reve, c'est un reveil qui commence." *

* A dream is the beginning of wakening.

It has already been pointed out by Dugas that Goblot, in order to generalize his theory, was forced to ignore a great many facts. There are also dreams from which we do not awaken; for example, many dreams in which we dream that we dream. From our knowledge of the dream-work, we can by no means admit that it extends only over the period of waking. On the contrary, we must consider it probable that the first part of the dream-work is already begun during the day, when we are still under the domination of the preconscious. The second phase of the dream-work, viz., the alteration by the censorship, the attraction exercised by unconscious scenes, and the penetration to perception, continues probably all through the night, and accordingly we may always be correct when we report a feeling that we have been dreaming all night, even although we cannot say what we have dreamed. I do not however, think that it is necessary to assume that up to the time of becoming conscious the dream-processes really follow the temporal sequence which we have described; viz., that there is first the transferred dream- wish, then the process of distortion due to the censorship, and then the change of direction to regression, etc. We were obliged to construct such a sequence for the sake of description; in reality, however, it is probably rather a question of simultaneously trying this path and that, and of the excitation fluctuating to and fro, until finally, because it has attained the most apposite concentration, one particular grouping remains in the field. Certain personal experiences even incline me to believe that the dream-work often requires more than one day and one night to produce its result, in which case the extraordinary art manifested in the construction of the dream is shorn of its miraculous character. In my opinion, even the regard for the comprehensibility of the dream as a perceptual event may exert its influence before the dream attracts consciousness to itself. From this point, however, the process is accelerated, since the dream is henceforth subjected to the same treatment as any other perception. It is like fire works, which require hours for their preparation and then flare up in a moment.

Through the dream-work, the dream-process now either gains sufficient intensity to attract consciousness to itself and to arouse the preconscious (quite independently of the time or profundity of sleep), or its intensity is insufficient, and it must wait in readiness until attion, becoming more alert immediately before waking, meets it half-way. Most dreams seem to operate with relatively slight psychic intensities, for they wait for the process of waking. This, then, explains the fact that as a rule we perceive something