The widespread notion of prophetic dream is probably based upon a belief, almost as widely diffused, that in sleep the Soul can and does sometimes pass out of the body and obtain information by direct impressions received through its own vastly extended power of perception. It is not uncommon to hear an assertion, when a place is seen for the first time, that there is a memory of the same place having been seen before, and there are some curious reports of cases of this kind that deserve to be investigated. But many of these apparent marvels may be accounted for by coincidence or by memories of which the link has been lost. When the multiplicity of dreams that occur in a lifetime are taken into account, occasional resemblances of external objects or events to some portions of former dreams are by no means improbable. The same explanation applies to many dreams that are supposed to have been prophetic because something afterwards occurs having some resemblance to the dream. Memory also has a large share in these recognitions. Memory may exist without recollection. Thousands of things are stored away in the memory which we cannot recal even if we try to do so, but which come back to us suddenly, at unexpected times, for no cause that we can trace although certainly suggested by something associated with the revived idea. Thus the eye may well recognise a strange place as having been seen when, in fact, the memory has unconsciously received some picture of it or of some place very like it, the existence of which had been forgotten, but which is now revived by the suggestion of the place itself. Somnambulism, although commonly supposed to be a phase of sleep, has really no relationship to it. Its physiological and psychical conditions are entirely different. There is the aspect of sleep, but nothing more. The somnambule is not sleeping, for he performs often the work of his waking life although with certainly closed eyes and probably sealed up senses. The somnambule has no memory of the doings of either mind or body during his trance existence. The sleeper is conscious at the time of dreaming and remembers his dream. As there is Somnambulism without sleep, so there may be Somnambulism in sleep, and indeed, with a constitutional tendency to it, the state of sleep is so favourable to the inducement of the condition of Somnambulism that the one may well lapse into the other. Nor is “sleep walking” the only exhibition of Somnambulism; it is but one stage of it. Somnambulism often occurs without action of any limb, for it is a mental and not a muscular condition. But, inasmuch as the uninformed spectator notes only the instances of “sleep walking,” the much more numerous cases of somnambulism occurring with the patient at rest are unnoticed.