discoveries. It is quite true that symbolizations of the bodily organs and functions do occur in dreams: for example, that water in a dream often signifies a desire to urinate, that the male genital organ may be represented by an upright staff, or a pillar, etc. With dreams which exhibit a very animated field of vision and brilliant colours, in contrast to the dimness of other dreams, the interpretation that they are "dreams due to visual stimulation" can hardly be dismissed, nor can we dispute the participation of illusion-formation in dreams which contain noise and a medley of voices. A dream like that of Scherner's, that two rows of fair handsome boys stood facing one another on a bridge, attacking one another, and then resuming their positions, until finally the dreamer himself sat down on a bridge and drew a long tooth from his jaw; or a similar dream of Volkelt's, in which two rows of drawers played a part, and which again ended in the extraction of a tooth; dream-formations of this kind, of which both writers relate a great number, forbid our dismissing Scherner's theory as an idle invention without seeking the kernel of truth which may be contained in it. We are therefore confronted with the task of finding a different explanation of the supposed symbolization of the alleged dental stimulus.

Throughout our consideration of the theory of the somatic sources of dreams, I have refrained from urging the argument which arises from our analyses of dreams. If, by a procedure which has not been followed by other writers in their investigation of dreams, we can prove that the dream possesses intrinsic value as psychic action, that a wish supplies the motive of its formation, and that the experiences of the previous day furnish the most obvious material of its content, any other theory of dreams which neglects such an important method of investigation- and accordingly makes the dream appear a useless and enigmatical psychic reaction to somatic stimuli- may be dismissed without special criticism. For in this case there would have to be- and this is highly improbable- two entirely different kinds of dreams, of which only one kind has come under our observation, while the other kind alone has been observed by the earlier investigators. It only remains now to find a place in our theory of dreams for the facts on which the current doctrine of somatic dream-stimuli is based.

We have already taken the first step in this direction in advancing the thesis that the dream-work is under a compulsion to elaborate into a unified whole all the dream-stimuli which are simultaneously present (chapter V., A, above). We have seen that when two or more experiences capable of making an impression on the mind have been left over from the previous day, the wishes that result from them are united into one dream; similarly, that the impressions possessing psychic value and the indifferent experiences of the previous day unite in the dream-material, provided that connecting ideas between the two can be established. Thus the dream appears to be a reaction to everything which is simultaneously present as actual in the sleeping mind. As far as we have hitherto analysed the dreammaterial, we have discovered it to be a collection of psychic remnants and memory-traces, which we were obliged to credit (on account of the preference shown for recent and for infantile material) with a character of psychological actuality, though the nature of this actuality was not at the time determinable. We shall now have little difficulty in predicting what will happen when to these actualities of the memory fresh material in the form of sensations is added during sleep. These stimuli, again, are of importance to the dream because they are actual; they are united with the other psychic actualities to provide the material for dream-formation. To express it in other words, the stimuli which occur during sleep are elaborated into a wish-fulfilment, of which the other components are the psychic remnants of daily experience with which we are already familiar. This combination, however, is not inevitable; we have seen that more than one kind of behaviour toward the physical stimuli received during sleep is possible. Where this combination is effected, a conceptual material for the dream-content has been found which will represent both kinds of dream-sources, the somatic as well as the psychic.

The nature of the dream is not altered when somatic material is added to the psychic dream-sources; it still remains a wish fulfilment, no matter how its expression is determined by the actual material available.

I should like to find room here for a number of peculiarities which are able to modify the significance of external stimuli for the dream. I imagine that a co-operation of individual, physiological and accidental factors, which depend on the circumstances of the moment, determines how one will behave in individual cases of more intensive objective stimulation during sleep; habitual or accidental profundity of sleep,