The answer of actual experience to these questions is unexpectedly direct and clear. In every recorded instance--so far at least as my memory serves me, where there has been any _unification_ between alternating states, so as to make comparison possible--it is the memory furthest from waking life whose span is the widest, whose grasp of the organism's upstored impressions is the most profound. Inexplicable as this phenomenon has been to observers who have encountered it without the needed key, the independent observations of hundreds of physicians and hypnotists have united in affirming its reality. The commonest instance, of course, is furnished by the ordinary hypnotic trance. The degree of intelligence, indeed, which finds its way to expression in that trance or slumber varies greatly in different subjects and at different times. But whensoever there is enough of alertness to admit of our forming a judgment, we find that in the hypnotic state there is a considerable memory--though not necessarily a complete or a reasoned memory--of the waking state; whereas with most subjects in the waking state--unless some special command be imposed upon the hypnotic self--there is no memory whatever of the hypnotic state. In many hysterical conditions also the same general rule subsists; namely, that the further we get from the surface the wider is the expanse of memory which we encounter. If all this be true, there are several points on which we may form expectations definite enough to suggest inquiry. Ordinary sleep is roughly intermediate between waking life and deep hypnotic trance; and it seems _a priori_ probable that its memory will have links of almost equal strength with the memory which belongs to waking life and the memory which belongs to the hypnotic trance. And this is in fact the case; the fragments of dream-memory are interlinked with both these other chains. Thus, for example, without any suggestion to that effect, acts accomplished in the hypnotic trance may be remembered in dream; and remembered under the illusion which was thrown round them by the hypnotiser. Thus Dr. Auguste Voisin suggested to a hypnotised subject to stab a patient--really a stuffed figure--in the neighbouring bed.[44] The subject did so; and of course knew nothing of it on waking. But three days afterwards he returned to the hospital complaining that his dreams were haunted by the figure of a woman, who accused him of having stabbed and killed her. Appropriate suggestion laid this ghost of a doll.