Somnambulism.--These curiously vivid dreams are occasionally associated with somnambulistic phenomena. Sometimes very definite purposes, requiring careful adaptation of means to ends, are accomplished in the somnambulistic state, and yet the actions are completely forgotten. I have recently been consulted about a case in which a young woman, on a visit to a family, had been shown some pretty though not expensive jewels. Evidently the guest envied their possession, for she got up during sleep and took the jewels and hid them. There seems no reason to doubt her statement that she remembered nothing at all about the incident. The taking was not attributed to her. There had been previous experiences of the same kind with things belonging to this young woman's sister. Somnambulism represents a degree of unconscious cerebration that may have serious results. Combinations of intellectual work with somnambulism are not infrequent, though many of the stories that are told are exaggerated. Some of them are authenticated. Ribot has a typical example of intellectual accomplishment, in a somnambulistic condition, that shows how far this may go: A clear case of somnambulism was that of a clergyman, whom his wife saw rise from bed in his sleep, go to a writing table, and write rapidly for some minutes. This done he returned to bed, and slept on until morning. On awaking, he told her that in a dream he had worked out an argument for a sermon, of which he now retained no recollection whatever. She led him to the writing table, and showed him the written sheet upon which he found his argument worked out in the most satisfactory manner. PATHOLOGICAL SIGNIFICANCE Unconscious cerebration is not, then, a trivial matter, and not an unusual experience. It probably occurs in every individual to a much greater extent than he thinks, unless he is engaged in analyzing his mental processes and their ways rather carefully. This constitutes one of the dangers of the intellectual life, which must also be guarded against in business life or in any absorbing occupation. When the mind has become intensely occupied with a subject, it is not easy to relinquish it. Even when we turn to something else, mental activity in the old groove continues to some extent, and so will prevent the rest that is necessary for the repair of tissue. Under these conditions the _re-creation_ that is so important does not take place quite as well as it should, and even sleep does not relieve us from the burden of mental work. Mental exhaustion will result as a consequence of constant occupation, and so mental relaxation must be secured. Deliberate means and methods must be employed in order that we may not deceive ourselves into thinking we are securing mental recreation, though all the time certain exhausting mental processes continue to be active.