But we found reason to believe that the subliminal self has other functions to fulfil during sleep. Those other functions are concerned in some unknown way with the spiritual world; and the indication of their exercise is given by the sporadic occurrence, in the sleeping phase, of supernormal phenomena. Such phenomena, as we shall presently see, occur also at various points in hypnotic practice. To them we must now turn, if our account of the phenomena of induced somnambulism is to be complete. Yet here, in order to give completeness to our intended review, we shall need a certain apparent extension of the scope of this chapter. We shall need to consider a group of cases which might have been introduced at various points in our scheme, but which are perhaps richest in their illustrations of the supernormal phenomena of hypnotism. _Spontaneous somnambulisms_,--those crude uprushes of incoherent subliminal faculty which sometimes break through the surface of sleep,--seem to occupy a kind of midway position among the various phenomena through which our inquiry has thus far carried us. The somnambulism often _starts_ as an exaggerated dream; it _develops_ into a kind of secondary personality. The thoughts and impulses which the upheaval raises into manifestations--the psychical output--resemble sometimes the inspirations of genius, sometimes the follies of hysteria. And, finally, the spontaneous sleep-waking state itself is manifestly akin to hypnosis,--is sometimes actually interchangeable with the induced somnambulisms of the hypnotic trance. The _chain of memory_ which repeated spontaneous somnambulisms gradually form,--while lying quite outside the primary or waking memory,--will often be found to form a part of the _hypnotic_ memory, which gradually accretes in similar fashion from repeated hypnosis. For one form of sleep-waking capacity we are already prepared by what has been said in Chapter IV. of the solution of problems in sleep. This is one of the ways in which we can watch the gradual merging of a vivid dream into a definite somnambulic act. The solution of a problem (as we have seen) may present itself merely as a sentence or a diagram, constructed in dream and remembered on waking. Or the sleeper (as in various cases familiar in text-books) may rise from bed and _write out_ the chain of reasoning, or the sermon, or whatever it may be. Or again, in rarer cases the somnambulic output may take the form of oratory, and edifying discourses may be delivered by a preacher whom no amount of shaking or pinching will silence or, generally, even interrupt. This, so to speak, is genius with a vengeance; this is a too persistent uprush of subliminal zeal, co-operating even out of season with the hortatory instincts of the waking self.