reactions occur quite as frequently as the reaction of dream-formation. This, however, would not be the case if the incentive to dreaming did not lie outside the somatic dream-sources.

Appreciating the importance of the above-mentioned lacunae in the explanation of dreams by somatic stimuli, other writers- Scherner, for example, and, following him, the philosopher Volkelt- endeavoured to determine more precisely the nature of the psychic activities which cause the many-coloured images of our dreams to proceed from the somatic stimuli, and in so doing they approached the problem of the essential nature of dreams as a problem of psychology, and regarded dreaming as a psychic activity. Scherner not only gave a poetical, vivid and glowing description of the psychic peculiarities which unfold themselves in the course of dream-formation, but he also believed that he had hit upon the principle of the method the mind employs in dealing with the stimuli which are offered to it. The dream, according to Scherner, in the free activity of the phantasy, which has been released from the shackles imposed upon it during the day, strives to represent symbolically the nature of the organ from which the stimulus proceeds. Thus there exists a sort of dream-book, a guide to the interpretation of dreams, by means of which bodily sensations, the conditions of the organs, and states of stimulation, may be inferred from the dream-images. "Thus the image of a cat expressed extreme ill-temper; the image of pale, smooth pastry the nudity of the body. The human body as a whole is pictured by the phantasy of the dream as a house, and the individual organs of the body as parts of the house. In toothache-dreams a vaulted vestibule corresponds to the mouth, and a staircase to the descent from the pharynx to the oesophagus; in the headache-dream a ceiling covered with disgusting toad-like spiders is chosen to denote the upper part of the head." "Many different symbols are employed by our dreams for the same organ: thus the breathing lung finds its symbol in a roaring stove, filled with flames, the heart in empty boxes and baskets, and the bladder in round, bag-shaped or merely hollow objects. It is of particular significance that at the close of the dream the stimulating organ or its function is often represented without disguise and usually on the dreamer's own body. Thus the toothache-dream commonly ends by the dreamer drawing a tooth out of his mouth." It cannot be said that this theory of dream-interpretation has found much favour with other writers. It seems, above all, extravagant; and so Scherner's readers have hesitated to give it even the small amount of credit to which it is, in my opinion, entitled. As will be seen, it tends to a revival of dream-interpretation by means of symbolism, a method employed by the ancients; only the province from which the interpretation is to be derived is restricted to the human body. The lack of a scientifically comprehensible technique of interpretation must seriously limit the applicability of Scherner's theory. Arbitrariness in the interpretation of dreams would appear to be by no means excluded, especially since in this case also a stimulus may be expressed in the dream-content by several representative symbols; thus even Scherner's follower Volkelt was unable to confirm the representation of the body as a house. Another objection is that here again the dream-activity is regarded as a useless and aimless activity of the mind, since, according to this theory, the mind is content with merely forming phantasies around the stimulus with which it is dealing, without even remotely attempting to abolish the stimulus.

Scherner's theory of the symbolization of bodily stimuli by the dream is seriously damaged by yet another objection. These bodily stimuli are present at all times, and it is generally assumed that the mind is more accessible to them during sleep than in the waking state. It is therefore impossible to understand why the mind does not dream continuously all night long, and why it does not dream every night about all the organs. If one attempts to evade this objection by positing the condition that special excitations must proceed from the eye, the ear, the teeth, the bowels, etc., in order to arouse the dream-activity, one is confronted with the difficulty of proving that this increase of stimulation is objective; and proof is possible only in a very few cases. If the dream of flying is a symbolization of the upward and downward motion of the pulmonary lobes, either this dream, as has already been remarked by Strumpell, should be dreamt much oftener, or it should be possible to show that respiration is more active during this dream. Yet a third alternative is possible- and it is the most probable of all- namely, that now and again special motives are operative to direct the attention to the visceral sensations which are constantly present. But this would take us far beyond the scope of Scherner's theory.

The value of Scherner's and Volkelt's disquisitions resides in their calling our attention to a number of characteristics of the dream-content which are in need of explanation, and which seem to promise fresh