succeed in doing it, or in doing it completely. Unsolved problems, harassing cares, overwhelming impressions, continue the activity of our thought even during sleep, maintaining psychic processes in the system which we have termed the preconscious. The thought-impulses continued into sleep may be divided into the following groups:

1. Those which have not been completed during the day, owing to some accidental cause.

2. Those which have been left uncompleted because our mental powers have failed us, i.e., unsolved problems.

3. Those which have been turned back and suppressed during the day. This is reinforced by a powerful fourth group:

4. Those which have been excited in our Ucs during the day by the workings of the Pcs; and finally we may add a fifth, consisting of:

5. The indifferent impressions of the day, which have therefore been left unsettled.

We need not underrate the psychic intensities introduced into sleep by these residues of the day's waking life, especially those emanating from the group of the unsolved issues. It is certain that these excitations continue to strive for expression during the night, and we may assume with equal certainty that the state of sleep renders impossible the usual continuance of the process of excitation in the preconscious and its termination in becoming conscious. In so far as we can become conscious of our mental processes in the ordinary way, even during the night, to that extent we are simply not asleep. I cannot say what change is produced in the Pcs system by the state of sleep, * but there is no doubt that the psychological characteristics of sleep are to be sought mainly in the cathectic changes occurring just in this system, which dominates, moreover, the approach to motility, paralysed during sleep. On the other hand, I have found nothing in the psychology of dreams to warrant the assumption that sleep produces any but secondary changes in the conditions of the Ucs system. Hence, for the nocturnal excitations in the Pcs there remains no other path than that taken by the wish-excitations from the Ucs; they must seek reinforcement from the Ucs, and follow the detours of the unconscious excitations. But what is the relation of the preconscious day-residues to the dream? There is no doubt that they penetrate abundantly into the dream; that they utilize the dream-content to obtrude themselves upon consciousness even during the night; indeed, they sometimes even dominate the dream-content, and impel it to continue the work of the day; it is also certain that the day-residues may just as well have any other character as that of wishes. But it is highly instructive, and for the theory of wish-fulfilment of quite decisive importance, to see what conditions they must comply with in order to be received into the dream.

* I have endeavoured to penetrate farther into the relations of the sleeping state and the conditions of hallucination in my essay, "Metapsychological Supplement to the Theory of Dreams," Collected Papers, IV, p. 137.

Let us pick out one of the dreams cited above, e.g., the dream in which my friend Otto seems to show the symptoms of Basedow's disease (chapter V., D). Otto's appearance gave me some concern during the day, and this worry, like everything else relating to him, greatly affected me. I may assume that this concern followed me into sleep. I was probably bent on finding out what was the matter with him. During the night my concern found expression in the dream which I have recorded. Not only was its content senseless, but it failed to show any wish-fulfilment. But I began to search for the source of this incongruous expression of the solicitude felt during the day, and analysis revealed a connection. I identified my friend Otto with a certain Baron L and myself with a Professor R. There was only one explanation of my being impelled to select just this substitute for the day- thought. I must always have been ready in the Ucs to identify myself with Professor R, as this meant the realization of one of the immortal infantile wishes, viz., the wish to become great. Repulsive ideas respecting my friend, ideas that would certainly have been repudiated in a waking state, took advantage of the opportunity to creep into the dream; but the