that state of the body in which, though the vital functions continue, the senses are not affected by the ordinary impressions of external objects. See DREAMS and PHYSIOLOGY.

SLEEP-WALKER, one who walks in his sleep. Many instances might be related of persons who were addicted to this practice; but it will be sufficient to select one remarkable instance from a report made to the Physical Society of Lausanne, by a committee of gentlemen appointed to examine a young man who was accustomed to walk in his sleep.

"The disposition to sleep-walking seems, in the opinion of this committee, to depend on a particular affection of the nerves, which both seizes and quits the patient during sleep. Under the influence of this affection, the imagination represents to him the objects that struck him while awake, with as much force as if they really affected his senses; but does not make him perceive any of those that are actually presented to his senses, except in so far as they are connected with the dreams which engross him at the time. If, during this state, the imagination has no determined purpose, he receives the impression of objects as if he were awake; only, however, when the imagination is excited to bend its attention towards them. The perceptions obtained in this state are very accurate, and, when once received, the imagination renews them occasionally with as much force as if they were again acquired by means of the senses. Lastly, these academicians suppose, that the impressions received during this state of the senses disappear entirely when the person awakes, and do not return till the return of the same disposition in the nervous system.

"Their remarks were made on the Sieur Devaud, a lad thirteen years and a half old, who lives in the town of Vevey, and who is subject to that singular affection or disease called Somnambulism or sleep-walking. This lad possesses a strong and robust constitution, but his nervous system appears to be organized with peculiar delicacy, and to discover marks of the greatest sensibility and irritability. His senses of smell, taste, and touch, are exquisite; he is subject to fits of immoderate and involuntary laughter, and he sometimes likewise weeps without any apparent cause.

"This young man does not walk in his sleep every night; several weeks sometimes pass without any appearance of a fit. He is subject to the disease generally two nights successively, one fit lasting for several hours. The longest are from three to four hours, and they commonly begin about three or four o'clock in the morning.

"The fit may be prolonged, by gently passing the finger or a feather over his upper lip, and this slight irritation likewise accelerates it. Having once fallen asleep upon a chair, his upper lip was thus irritated with a feather, when he immediately ran down the steps with great precipitation, and returned all his accustomed activity. This experiment was repeated several times.

"The young Devaud thinks he has observed, that, on the evenings previous to a fit, he is sensible of a certain heaviness in his head, but especially of a great weight in his eyelids.

"His sleep is at all times unquiet, but particularly when the fits are about to seize him. During his sleep, motions are observable in every part of his body, with starting and palpitations; he utters broken words, sometimes sits up in his bed, and afterwards lies down again. He then begins to pronounce words more distinctly, he rises abruptly, and acts as he is instigated by the dream that then possesses him. He is sometimes in sleep subject to continued and involuntary motions.

"The departure of the fit is always preceded by two or three minutes of calm sleep, during which he snores. He then awakes rubbing his eyes like a person who has slept quietly.

"It is dangerous to awaken him during the fit, especially if it is done suddenly; for then he sometimes falls into convulsions. Having risen one night with the intention of going to eat grapes, he left the house, passed through the town, and went to a vineyard where he expected good cheer. He was followed by several persons, who kept at some distance from him, one of whom fired a pistol, the noise of which instantly awakened him, and he fell down without sense. He was carried home and brought to himself, when he recollected very well the Sleep-walker.

having been awakened in the vineyard; but nothing more, except the fright at being found there alone, which had made him fwoon.

"After the fits he generally feels a degree of lassitude: sometimes, though rarely, of indisposition. At the end of one of those fits, of which the gentlemen of the committee were witnesses, he was affected with vomitings; but he is always soon restored.

"When he is awaked, he never for the most part recollects any of the actions he has been doing during the fit.

"The subject of his dreams is circumscribed in a small circle of objects, that relate to the few ideas with which at his age his mind is furnished; such as his lessons, the church, the bells, and especially tales of ghosts. It is sufficient to strike his imagination the evening before a fit with some tale, to direct his somnambulism towards the object of it. There was read to him while in this situation the story of a robber; he imagined the very next moment that he saw robbers in the room. However, as he is much disposed to dream that he is surrounded with them, it cannot be affirmed that this was an effect of the reading. It is observed, that when his supper has been more plentiful than usual, his dreams are more dismal.

"In their report, the gentlemen of the committee dwell much on the state of this young man's senses, on the impression made upon them by strange objects, and on the use they are of to him.

"A bit of strong smelling wood produced in him a degree of restlessness; the fingers had the same effect, whether from their smell or their transpiration. He knew wine in which there was wormwood by the smell, and said that it was not wine for his table. Metals make no impression on him.

"Having been presented with a little common wine while he was in a state of apathy, and all his motions were performed with languor, he drank it willingly; but the irritation which it occasioned produced a deal of vivacity in all his words, motions, and actions, and caused him to make involuntary grimaces.

"Once he was observed dressing himself in perfect darkness. His clothes were on a large table, mixed with those of some other persons; he immediately perceived this, and complained of it much; at last a small light was brought, and then he dressed himself with sufficient precision. If he is teased or gently pinched, he is always sensible of it, except he is at the time strongly engrossed with some other thing, and wishes to strike the offender; however, he never attacks the person who has done the ill, but an ideal being whom his imagination presents to him, and whom he pursues through the chamber without running against the furniture, nor can the persons whom he meets in his way divert him from his pursuit.

"While his imagination was employed on various subjects, he heard a clock strike, which repeated at every stroke the note of the cuckoo. There are cuckoos here, said he; and upon being desired, he imitated the song of that bird immediately.

"When he wishes to see an object, he makes an effort to lift his eyelids; but they are so little under his command, that he can hardly raise them a line or two, while he draws up his eyebrows; the iris at that time appears fixed, and his eye dim. When any thing is presented to him, and he is told of it, he always half opens his eyes with a degree of difficulty, and then shuts them after he has taken what was offered to him.

"The report infers from these facts, and from many others relative to the different sensés, that their functions are not suspended as to what the sleep-walker wishes to see, that is, as to all those perceptions which accord with the objects about which his imagination is occupied; that he may also be disposed to receive those impressions, when his imagination has no other object at the time; that in order to see, he is obliged to open his eyes as much as he can, but when the impression is once made, it remains; that objects may strike his sight without striking his imagination, if it is not interested in them; and that he is sometimes informed of the presence of objects without either seeing or touching them.

"Having engaged him to write a theme, say the committee, we saw him light a candle, take pen, ink, and paper, from the drawer of his table, and begin to write, while his matter dictated. As he was writing, we put a thick paper before his eyes, notwithstanding which he continued to write and to form his letters very distinctly; showing signs, however, that something was incommoding him, which apparently proceeded from the obtrusion which the paper, being held too near his nose, gave to his respiration.

"Upon another occasion, the young somnambulist arose at five o'clock in the morning, and took the necessary materials for writing, with his copy-book. He meant to have begun at the top of a page; but finding it already written on, he came to the blank part of the leaf, and wrote some time from the following words, Fiunt ignari pigritia—Ils deviennent ignorans par la paresse; and, what is remarkable, after several lines he perceived he had forgotten the s in the word ignorans, and had put erroneously a double r in paresse; he then gave over writing, to add the s he had forgotten, and to erase the superfluous r.

"Another time he had finished, of his own accord, a piece of writing, in order, as he said, to please his master. It consisted of three kinds of writing, text, half text, and small hand; each of them performed with the proper pen. He drew, in the corner of the same paper, the figure of a hat; he then asked for a penknife to take out a blot of ink which he had made between two letters, and he erased it without injuring them. Lastly, he made some arithmetical calculations with great accuracy.

"In order to explain some of the facts observed by the academicians which we have here mentioned, they establish two general observations, which result from what they have said with respect to the sensés and the dreams of this sleep-walker.

"1. That he is obliged to open his eyes, in order to recognise objects which he wishes to see; but the impression once made, although rapidly, is vivid enough to supersede the necessity of his opening them again, to view the same objects anew; that is, the same objects are afterwards presented to his imagination with as much force and precision as if he actually saw them.

"2. That his imagination, thus warmed, represents to him objects, and such as he figures to himself, with as much vivacity as if he really saw them; and, lastly, that all his sensés, being subordinate to his imagination, seem concentrated in the object with which it is occupied, and have at that time no perception of any thing but what relates to that object.

"These two causes united seem to them sufficient for explaining one of the most singular facts that occurred to their observation, to wit, how the young Devaud can write, although he has his eyes shut, and an obstacle before them. His paper is imprinted on his imagination, and every letter which he means to write is also painted there, at the place in which it ought to stand on the paper, and without being confounded with the other letters; now it is clear that his hand, which is obedient to the will of his imagination, will trace them on the real paper, in the same order in which they are represented on that which is pictured in his head. It is thus that he is able to write several letters, several sentences, and entire pieces of writing; and what seems to confirm the idea, that the young Devaud writes according to the paper painted on his imagination is, that a certain sleep-walker, who is described in the French Encyclopédie (article Somnambulisme), having written something on a paper, another piece of paper of the same size was substituted in its stead, which he took for his own, and made upon this blank paper the corrections he meant to have made on the other which had been taken away, precisely in the places where they would have been.

"It appears from the recital of another fact, that Devaud, intending to write at the top of the first leaf of a white paper book, Vevey, le— stopped a moment as if to recollect the day of the month, left a blank space, and then proceeded to Décembre 1787; after which he asked for an almanac: a little book, such as is given to children for a new year's gift, was offered to him; he took it, opened it, brought it near his eyes, then threw it down on the table. An almanac which he knew was then presented to him; this was in German, and of a form similar to the almanac of Vevey: he took it, and then said, 'What is this they have given me; here, there is your German almanac.' At last they gave him the almanac of Borne; he took this likewise, and went to examine it at the bottom of an alcove that was perfectly dark. He was heard turning over the leaves, and saying 24, then a moment afterwards 34. Returning to his place, with the almanac open at the month of December, he laid it on the table and wrote in the space which he had left blank the 24th. This scene happened on the 23d; but as he imagined it to be the 24th, he did not mistake. The following is the explication given of this fact by the authors of the report.

"The dates 23d, 24th, and 25th, of the month of December, had long occupied the mind of the young Devaud. The 23d and 25th were holidays, which he expected with the impatience natural to persons of his age, for the arrival of those moments when their little daily labours are to be suspended. The 25th especially was the object of his hopes; there was to be an illumination in the church, which had been described to him in a manner that quite transported him. The 24th was a day of labour, which came very disagreeably between the two happy days. It may easily be conceived, how an imagination so irritable as that of the young Devaud would be struck with those pleasing epochs. Accordingly, from the beginning of the month he had been perpetually turning over the almanac of Vevey. He calculated the days and the hours that were to elapse before the arrival of his wished-for holidays; he showed to his friends and acquaintance the dates of those days which he expected with so much impatience; every time he took up the almanac, it was only to consult the month of December. We now see why that date presented itself to his mind. He was performing a task, because he imagined the day to be the Monday which had so long engrossed him. It is not surprising, that it should have occurred to his imagination, and that on opening the almanac in the dark he might have thought he saw this date which he was seeking, and that his imagination might have represented it to him in as lively a manner as if he had actually seen it. Neither is it surprising that he should have opened the almanac at the month of December; the custom of perusing this month must have made him find it in the dark by a mere mechanical operation. Man never seems to be a machine so much as in the state of somnambulism; it is then that habit comes to supply those of the senses that cannot be serviceable, and that it makes the person act with as much precision as if all his senses were in the utmost activity. These circumstances destroy the idea of there being any thing miraculous in the behaviour of young Devaud with respect to the date and the month that he was in quest of; and the reader, who has entered into our explanations, will not be surprised at his knowing the German almanac; the touch alone was sufficient to point it out to him; and the proof of this is the shortness of the time that it remained in his hands.

"An experiment was made by changing the place of the ink-standish during the time that Devaud was writing. He had a light beside him, and had certified himself of the place where his ink-holder was standing by means of sight. From that time he continued to take ink with precision, without being obliged to open his eyes again: but the ink-standish being removed, he returned as usual to the place where he thought it was; It must be observed, that the motion of his hand was rapid till it reached the height of the standish, and then he moved it slowly, till the pen gently touched the table as he was seeking for the ink: he then perceived that a trick had been put on him, and complained of it; he went in search of his ink-standish and put it in its place. This experiment was several times repeated, and always attended with the same circumstances. Does not what we have here stated prove, that the standish, the paper, the table, &c. are painted on his imagination in as lively a manner as if he really saw them, as he sought the real standish in the place where his imagination told him it ought to have been? Does it not prove that the same lively imagination is the cause of the most singular actions of this sleep-walker? And lastly, does it not prove, that a mere glance of his eye is sufficient to make his impressions as lively as durable?

"The committee, upon the whole, recommend to such as wish to repeat the same experiments, 1. To make their observations on different sleep-walkers. 2. To examine often whether they can read books that are unknown to them in perfect darkness. 3. To observe whether they can tell the hours on a watch in the dark. 4. To remove when they write the ink-standish from its place, to see whether they will return to the same place in order to take ink. 5. And, lastly, to take notice whether they walk with the same confidence in a dark and unknown place, as in one with which they are acquainted.

"They likewise recommend to such as would confirm or invalidate the above observations, to make all their experiments in the dark; because it has been hitherto supposed that the eyes of sleep walkers are of no use to them."