It has long been known that in dreams we are often able to recall more than when awake, of course involuntarily. Maury states that as a child he used to go from his native city, Meaux, to the neighbouring Trilport, where his father was building a bridge. One night, in adult life, he dreamt that he was a boy again, and that he was playing in the streets of his native Trilport. A man approached him, wearing some sort of a uniform. Maury asked the man his name. The man introduced himself as C . . . , and said that he was a bridge guard. On awaking, Maury asked his old servant if she remembered a man by that name. He was informed that the man used to be a watchman on the bridge that Maury's father was building at the time the dream pictured, and that the uniform was exactly like that worn by him.

Deleboeuf, in his Le Somneil et les Reves, discusses his dream in which the botanical name, "Asplenium Ruta Muralis," appeared as familiar. On awaking he could not place it. He found, long afterwards, the name written in his own handwriting in a collection of ferns and flowers. Swift1 mentions the case of a man who spoke Spanish almost exclusively when a young child. Later in life he forgot the language so completely that he was unable to recall voluntarily more than a few isolated words. In sleep, however, he frequently talked fluently and intelligibly in the language.

Probably most of us have noted from personal experience how reminiscent the dream is, and how well it pictures characters and scenes within the range of our experiences but which we are unable to voluntarily recalls When we recognize the dream images on awaking, we are not likely to be perplexed, but if the images cannot be placed some of us may tend toward a supernatural view of night life. However, we should be mindful of the fact that we have had many experiences which consciousness cannot identify. Sometimes this is because the experiences come to mind in fragments; they do not give rise to ideas by which they can be easily associated with some actual occurrence. Sometimes, too, the experiences were such as made but an insignificant impression, as far as emotional accompaniment is concerned, on the mind. Or it may be that the experiences we are unable to identify have been perceived subconsciously; it might be said that they passed so rapidly through consciousness as to be beyond the latter's power of recognition when again met with.

1 Op. cit., pp. 214-215.

The hypermnesia of dreams may be explained by say-ing that sleep opens the door to the unconscious mind, where all past experiences are preserved in all detail. But a better understanding of it may be obtained by bringing to mind the changes incident to sleep. Sleep is its own world; it removes one from the distractions of waking life, from mental tension, both of which are antagonistic to accurate reminiscence, especially of events that have long since passed into the limbo of things. Images come and go uninterruptedly; they are quickly associated with other images to which they bear a marked or slight relation, and, since there is a poverty of the. creative ideas which characterize directive thinking, the dream must concern itself with past experiences; these it tends to exhaust as the dream progresses, dealing more and more with the incidents of the dim past. Since the mind retains its impressions intact, any experience which is called forth from the recesses of memory is depicted in all accuracy.

While hypermnesia is probably more common in dreams than in waking thought, forgotten memories may also be noted in delerii, under the influence of drugs and anesthetics. Under suitable conditions, one may, with practice, be able to resurrect incidents of long ago more or less intentionally. The conditions are, principally, a removal of all stimuli apt to occupy consciousness, and abstraction. Sometimes a quiet, semi-dark room, and closing the eyes, permitting the thoughts to proceed without any attempt at criticism or direction, will meet the requirements. Some persons employ crystals, and are able to discover lost articles, and peer into their pasts. By the association test, psycho-analysis, and other methods employed by psychologists in an effort to bring to consciousness incidents of the patient's life which may be at the root of the neurosis for which treatment is sought, experiences which occurred as far back as childhood are often awakened, in exactly the same way as they actually occurred.