dream formation. To express it differently, the stimuli which appear during sleep are worked over into the fulfilment of a wish, the other component parts of which are the remnants of daily experience with which we are familiar. This union, however, is not inevitable; we have heard that more than one sort of attitude towards bodily stimuli is possible during sleep. Wherever this union has been brought about, it has simply been possible to find for the dream content that kind of presentation material which will give representation to both classes of dream sources, the somatic as well as the psychic.
The essential nature of the dream is not changed by this addition of somatic material to the psychic sources of the dream; it remains the fulfilment of a wish without reference to the way in which its expression is determined by the actual material.
I shall gladly find room here for a number of peculiarities, which serve to put a different face on the significance of external stimuli for the dream. I imagine that a co-operation of individual, physiological, and accidental factors, conditioned by momentary circumstances, determines how one will act in each particular case of intensive objective stimulation during sleep; the degree of the profoundness of sleep whether habitual or accidental in connection with the intensity of the stimulus, will in one case make it possible to suppress the stimulus, so that it will not disturb sleep; in another case they will force an awakening or will support the attempt to overcome the stimulus by weaving it into the texture of the dream. In correspondence with the multiplicity of these combinations, external objective stimuli will receive expression more frequently in the case of one person than in that of another. In the case of myself, who am an excellent sleeper, and who stubbornly resists any kind of disturbance in sleep, this intermixture of external causes of irritation into my dreams is very rare, while psychic motives apparently cause me to dream very easily. I have indeed noted only a single dream in which an objective, painful source of stimulation is demonstrable, and it will be highly instructive to see what effect the external stimulus had in this very dream.
I am riding on a grey horse, at first timidly and awkwardly, as though I were only leaning against something. I meet a