According to Scherner, the material upon which the dream phantasy exerts its artistic activity is preponderately that of the organic sensory stimuli which are so obscure during the day (comp. p. 29); hence the phantastic theory of Scherner, and the perhaps over-sober theories of Wundt and other physiologists, though otherwise diametrically opposed, agree perfectly in their assumption of the dream sources and dream excitants. But whereas, according to the physiological theory, the psychic reaction to the inner physical stimuli becomes exhausted with the awakening of any ideas suitable to these stimuli, these ideas then by way of association calling to their aid other ideas, and with this stage the chain of psychic processes seeming to terminate according to Scherner, the physical stimuli only supply the psychic force with a material which it may render subservient to its phantastic intentions. For Scherner the formation of the dream only commences where in the conception of others it comes to an end. The treatment of the physical stimuli by the dream phantasy surely cannot be considered purposeful. The phantasy plays a tantalising game with them, and represents the organic source which gives origin to the stimuli in the correspondent dream, in any plastic symbolism. Indeed Scherner holds the opinion, not shared by Volkelt and others, that the dream phantasy has a certain favourite representation for the entire organism; this representation would be the _house_. Fortunately, however, it does not seem to limit itself in its presentation to this material; it may also conversely employ a whole series of houses to designate a single organ, _e.g._, very long rows of houses for the intestinal excitation. On other occasions particular parts of the house actually represent particular parts of the body, as _e.g._, in the headache-dream, the ceiling of the room (which the dream sees covered with disgusting reptile-like spiders) represents the head.