earlier perceptions, either unembellished or with the psychic values belonging to them, from the range of waking experiences, of which the mind has remained in possession. It seems to collect about itself, as it were, a greater or less number of such images, from which the impression which originates from the nerve-stimulus receives its psychic value. It is usually said here, as the idiom does of waking thought, that the mind interprets impressions of nerve-stimuli in sleep. The result of this interpretation is the so-called nerve-stimulus dream—that is to say, a dream whose composition is conditioned by the fact that a nerve-stimulus brings about its effect in psychic life according to the laws of reproduction."
The opinion of Wundt76 agrees in all essentials with this theory. He says that the ideas in the dream are probably the result, for the most part, of sensory stimuli, especially of those of general sensation, and are therefore mostly phantastic illusions—probably memory presentations which are only partly pure, and which have been raised to hallucinations. Strümpell has found an excellent simile (p. 84). It is as "if the ten fingers of a person ignorant of music should stray over the keyboard of an instrument"—to illustrate the relation between dream content and dream stimuli, which follows from this theory. The implication is that the dream does not appear as a psychic phenomenon, originating from psychic motives, but as the result of a physiological stimulus, which is expressed in psychic symptomology, because the apparatus which is affected by the stimulus is not capable of any other expression. Upon a similar assumption is based, for example, the explanation of compulsive ideas which Meynert tried to give by means of the famous simile of the dial on which individual figures are prominent because they are in more marked relief.
However popular this theory of somatic dream stimuli may have become, and however seductive it may seem, it is nevertheless easy to show the weak point in it. Every somatic dream stimulus which provokes the psychic apparatus to interpretation through the formation of illusions, is capable of giving rise to an incalculable number of such attempts at interpretation ; it can thus attain representation in the dream content by means of an extraordinary number of
