Conversely, dreams forgotten in waking life may be remembered in the hypnotic trance. Thus Dr. Tissié's patient, Albert, dreamt that he was about to set out on one of his somnambulic "fugues," or aimless journeys, and when hypnotised mentioned to the physician this dream, which in his waking state he had forgotten.[45] The probable truth of this statement was shown by the fact that he did actually set out on the journey thus dreamt of, and that his journeys were usually preceded and incited by remembered dreams. I need not dwell on the existence, but at the same time the incompleteness, of our dream-memory of waking life; nor on the occasional formation of a separate chain of memory, constructed from successive and cohering dreams. It should be added that we do not really know how far our memory in dream of waking life may have extended; since we can only _infer_ this from our notoriously imperfect waking memory of past dreams. A cognate anticipation to which our theory will point will be that dream-memory will occasionally be found to fill up gaps in waking memory, other than those due to hypnotic trance; such so-called "ecmnesic" periods, for instance, as sometimes succeed a violent shock to the system, and may even embrace some space of time _anterior_ to the shock. These periods themselves resemble prolonged and unremembered dreams. Such accidents, however, are so rare, and such dream-memory so hard to detect, that I mention the point mainly for the sake of theoretical completeness; and must think myself fortunate in being able to refer the reader to a recent case of M. Charcot's which affords an interesting confirmation of the suggested view.[46] I pass on to the still more novel and curious questions involved in the apparent existence of a dream-memory which, while accompanying the memory of ordinary life, seems also to have a wider purview, and to indicate that the record of external events which is kept within us is far fuller than we know. Let us consider what stages such a memory may show. I. It may include events once known to the waking self, but now definitely forgotten.