* Expressed more exactly: One portion of the symptom corresponds to the unconscious wish-fulfilment, while the other corresponds to the reaction-formation opposed to it.

*(2) Hughlings Jackson has expressed himself as follows: "Find out all about dreams, and you will have found out all about insanity."

*(3) Cf. my latest formulation (in Zeitschrift fur Sexual- wissenschaft, Bd. I) of the origin of hysterical symptoms in the treatise on "Hysterical Phantasies and their Relation to Bisexuality," Collected Papers, II, p. 51. This forms chapter X of Selected Papers on Hysteria, p. 115 above.

Of the dream we know as yet only that it expresses a wish- fulfilment of the unconscious; and apparently the dominant preconscious system permits this fulfilment when it has compelled the wish to undergo certain distortions. We are, moreover, not in fact in a position to demonstrate regularly the presence of a train of thought opposed to the dream-wish, which is realized in the dream as well as its antagonist. Only now and then have we found in dream-analyses signs of reaction-products as, for instance, my affection for my friend R in the dream of my uncle (chapter IV.). But the contribution from the preconscious which is missing here may be found in another place. The dream can provide expression for a wish from the Ucs by means of all sorts of distortions, once the dominant system has withdrawn itself into the wish to sleep, and has realized this wish by producing the changes of cathexis within the psychic apparatus which are within its power; thereupon holding on to the wish in question for the whole duration of sleep. *

* This idea has been borrowed from the theory of sleep of Liebault, who revived hypnotic research in modern times (Du Sommeil provoque, etc., Paris [1889]).

Now this persistent wish to sleep on the part of the preconscious has a quite general facilitating effect on the formation of dreams. Let us recall the dream of the father who, by the gleam of light from the death-chamber, was led to conclude that his child's body might have caught fire. We have shown that one of the psychic forces decisive in causing the father to draw this conclusion in the dream instead of allowing himself to be awakened by the gleam of light was the wish to prolong the life of the child seen in the dream by one moment. Other wishes originating in the repressed have probably escaped us, for we are unable to analyse this dream. But as a second source of motive- power in this dream we may add the father's desire to sleep, for, like the life of the child, the father's sleep is prolonged for a moment by the dream. The underlying motive is: "Let the dream go on, or I must wake up." As in this dream, so in all others, the wish to sleep lends its support to the unconscious wish. In chapter III. we cited dreams which were manifestly dreams of convenience. But in truth all dreams may claim this designation. The efficacy of the wish to go on sleeping is most easily recognized in the awakening dreams, which so elaborate the external sensory stimulus that it becomes compatible with the continuance of sleep; they weave it into a dream in order to rob it of any claims it might make as a reminder of the outer world. But this wish to go on sleeping must also play its part in permitting all other dreams, which can only act as disturbers of the state of sleep from within. "Don't worry; sleep on; it's only a dream," is in many cases the suggestion of the Pcs to consciousness when the dream gets too bad; and this describes in a quite general way the attitude of our dominant psychic activity towards dreaming, even though the thought remains unuttered. I must draw the conclusion that throughout the whole of our sleep we are just as certain that we are dreaming as we are certain that we are sleeping. It is imperative to disregard the objection that our consciousness is never directed to the latter knowledge, and that it is directed to the former knowledge only on special occasions, when the censorship feels, as it were, taken by surprise. On the contrary, there are persons in whom the retention at night of the knowledge that they are sleeping and dreaming becomes quite manifest, and who are thus apparently endowed with the conscious faculty of guiding their dream-life. Such a dreamer, for example, is dissatisfied with the turn taken by a dream; he breaks it off without waking, and begins it afresh, in order to continue it along different lines, just like a popular author who, upon request, gives a happier ending to his play. Or on another occasion, when the dream places him in a sexually exciting situation, he thinks in his sleep: "I don't want to continue this dream and exhaust myself by an emission; I would rather save it for a real situation."