the head, as compared with its general size, is always found connected with the possession of unusual mental power. Now, as no function of the brain can be carried on without a due supply of blood, it will follow, that the absence of such supply to the anterior part of the brain, will be attended, more or less, by a suspension of the activity of that part of the organ; and, on the contrary, a more than ordinary flow of blood to the head will produce quite a contrary effect. But the supine position of the body gives rise to the latter result, and hence, in going to bed, we have at once a pre-disposing cause to dream. Our author observes:

The posture of supination will unavoidably induce an increased flow of blood to the brain, which, under certain states of this fluid is so essential to the production of brilliant thoughts; an end, indeed, attained so often by another mode, the swallowing of opium. Some persons always retire to bed when they wish to think, and it is well known that Pope was often wont to ring for pens, ink, and paper in the night, that he might record, ere it was lost, that most sublime or fanciful poesy which flashed through his brain as he lay in bed. I deny not that the darkness or stillness of night may have had some influence during this inspiration; I may also allow that some few individuals compose best while they are walking, but this peripatetic exertion is calculated itself to produce what we term determination of blood to the head. The most remarkable instance of the power of position in influencing mental energy, is that of a German student, who was accustomed to study and compose with his head on the ground, and his feet elevated, and resting against the wall.'-pp, 53, 54.

It will be seen, that Mr. Dendy's theory of a pre-disposing cause resolves itself into that doctrine, which we before alluded to as having been formerly promulgated: namely, that the mind is in a morbid condition; that it is affected by a temporary delirium; or, that its power of maintaining order is suspended during the interval of dreaming.

The exciting cause of dreams is next considered by the author; and, as we regard the passage in which he explains that cause as one of the most original and interesting of the book, we shall not hesitate to transcribe it for our readers.

It seems to have been the opinion of Baron Haller, that what we term impression of a sense, is, in fact, mechanical; that the rays emanating from a body, and impinging on the retina, stamped an image on the brain: or, in the words of Aristotle, "As senses cannot receive material objects, but only their species." This idea regards, also, impression of the other senses. Mr. Locke held almost a similar notion. The argument involves the curious physiological question, in what consists the function of a nerve-in oscillation-in the motion of a fluid-in electricity, or magnetism? and, also, that subtle objection which Dr. Reid advanced against the opinion of Aristotle, and the more modern psychologists.

In the absence of a satisfactory answer to this question, it is certain that external impressions reach the brain through the medium of a nerve, and that when the fibrils, or extremities, of those nerves originally affected, are again irritated by their proper stimulus, and by the same, or a similar

body, an association is produced, and memory is the result. Now I cannot think but that this principle obtains, both in a waking thought, and in a dream. I have asserted that as the mind is gradually approaching the condition of sleep, or recovering from it, there is a state produced more or less approximating the more simple animal life, in which certain faculties may be perceived, but in which the power of correct association is not manifested. There is a curious calculation of Cabanis, that certain parts or senses of the body fall asleep at regular progressive periods; I can readily carry on this analogy to the faculties of mind. We may suppose that the faculty of judgment, as being the most important, is the first to feel fatigue, and to be influenced in the mode I have alluded to, by slumber. It is evident, then, that the other faculties which are still awake, will be uncontrolled, and an imperfect association will be the result, establishing the axiom I have ventured to advance. It is essential, however, that some object, or subject, be presented to the faculty of perception, ere this recurrence can take place. A sound, a touch, an odour, or a ray of light, may influence the sense and the brain: the idea, or thought, that had lain dormant, will then be re-excited by that mysterious sympathy of brain and nerve, and it will traverse the track of nerve from its origin to its fibrillous expansion on the organ of sense, or the spot at which the original impression was received, the only spot on which it can be re-excited.

'These reminiscences will occur sometimes in the most sudden and uuexpected manner. In one of the American Journals we are told of a clergyman, who, at the termination of some depressing malady, had completely lost his memory. His mind was a blank, and he had, in fact, to begin the world of literature again. Among other of his studies was the Latin language. During his classical readings with his brother, he one day suddenly struck his head with his hand, and stated that he had a most peculiar feeling, and was convinced that he had learned all this before.

'Boerhaave, in his Prelectiones Academic. Institut. Med., relates the case of a Spanish tragic writer, whose memory, subsequently to an acute febrile disease, was so completely impaired, that not only the literature of various languages he had studied was lost to him, but also their elements. the alphabets. When even his own poetic compositions were read to him, he denied himself to be the author. But the most interesting feature of the case is this, that on becoming again a votary of the muse, his recent compositions so intimately resembled his original productions in style and sentiment, that he no longer doubted that both were the offspring of his own imagination.

Another instance is that of the Countess of Laval, who had apparently forgotten the language of the Welch, among whom a portion of her childhood had been passed. After she had attained the adult age she had a fever, and during her delirium she again spoke Welch fluently. We are informed by Thucydides, that in many of those who survived the plague in Athens, the recollection of the names of their friends and themselves was for a time quite gone. It returned as health became more established.

But the faculty of memory may be impaired only from one certain period: the impressions previous to that time only being capable of renewal. In the case related by Dr. Abercrombie, of a lady reduced by diarrhoea, the memory of ten years was lost. "Her ideas were consistent with each other, but they referred to things as they stood before removal (to Edin

burgh)." In these instances it is probable that the fault may be referred to the original impression, some disorder or state of the brain causing it to be only superficially impressed during these ten years. It does not, I believe, require external impression of sense always to produce this excitement. We know that local congestions at the origin of nerves of sense will influence its condition, so as to render it additionally acute, or to destroy it altogether; and it is not impossible but that impression or excitement on that spot of brain on which the original image rested, may occasion this recurrence of ideas-memory.

That the possession of the faculty of this impression of memory can be demonstrated, we might doubt, were verbal description only employed; but when we see the artist trace the features of a person long lost to us, from memory, we know that such ideas existed, and were then re-excited in his mind.

That curious fact, the reference of pain to a toe or finger, after the amputation of the limb to which they belonged, is the effect of this memory. The impression of pain has been conveyed from the extreme fibrilla of the nerve to the brain. If, then, subsequent to amputation, any part of the remainder of that nerve be irritated or touched, the impression will be revived in the sensorium, and the erroneous sensation will for a time occur.'--pp. 57–64.

Although reason teaches us strongly to discredit the opinion, that dreams are especial revelations or warnings from heaven respecting futurity, still it cannot be denied, that a belief to that effect is far from being generally renounced even in our enlightened day. Stories are recorded, indeed, from time to time, on plausible authority, which serve to keep up the delusion of the divine origin of dreams but a careful investigation into these histories, and the testimony by which they are supported, will show that at best they only exhibit the curious results of mere coincidence. It is well observed by Mr. Dendy, that superstition on the nature and object of dreams should be discouraged as much as possible, since there are many examples of an untimely termination of life being the exclusive consequence of the bare apprehension of such a fatality.

I believe that many modern instances of gradual, and almost imperceptible decay, may be referred to the influence of melancholy visions on the mind, although this agency may be as obscure as that of the aqua tofana of the Italians.

The most interesting history of the sublime Requiem of Mozart, although not the recital of a dream, except that we might call the consequent train of thought of the composer, intense as it was, by that name, is highly illustrative of the influence of melancholy and sombre impressions in the production of a fatal result.

In the eras of inspiration few will be sceptical enough to doubt the occurrence of divine meditations during the silence of a dream, or deep sleep or not to believe with Socrates, and other sages, in the divine origin of dreams and omens. Although Socrates himself, however, believed and asserted that he was controlled in his actions by a familiar demon, it is the more rational opinion of some of his commentators, that this invisible

monitor was merely the impersonation of the faculty of judgment, and of that extensive knowledge and fore-thought with which his mind was fraught. The evidence of Holy Scripture proves the occasion, indeed, the necessity, for such communication; but in our own time, I should deem it little less than profaneness to imagine that the Deity should indicate the future occurrence of common-place and trivial incidents through the medium of an organ confessedly in a state of imperfection, at the moment when the faculties of mind are returning from a state of temporary suspension-a death-like sleep.

'Among those heathen tribes where this sentiment forms part of a national creed, we perceive it marked by a degree of blindness and inconsistency that may truly be termed mania: it is the doctrine, not of prophecy, but of debased and absolute fatalism. The North-American Indians not only regard the dream as prophetic, but often receive it as a solemn injunction, and are themselves the active agents in its fulfilment. "In whatever manner," says Charlevoix, "the dream is conceived, it is always looked upon as a thing sacred, and as the most ordinary way in which the gods make known their will to men. Filled with this idea, they cannot conceive how we should pay no regard to them. For the most part they look upon them either as a desire of the soul, inspired by some genius, or an order from him, and, in consequence of this principle, they hold it a religious duty to obey them. An Indian having dreamt of having a finger cut off, had it really cut off as soon as he awoke, having first prepared himself for this important action by a feast."'-pp. 74-77.

Dreams, in the view taken of them by Mr. Dendy, form only a portion of those transient illusions to which the mind of man is liable. The author accordingly appropriates a chapter to each of these causes of delusion under the distinct heads of somnambulism, reverie, spectral illusion, second-sight, and trance. With respect to somnambulism, or walking during sleep, Mr. Dendy considers it to be a state in which the mind suffers an intense degree of abstraction, and is nearer to the waking condition than when it is under the influence of what is properly called a dream. The somnambulist is generally actuated by some motive that guided his conduct when awake; he performs some one of his usual actions, and when he does so, executes them with a degree of perfection, which he cannot reach during those hours when he is in perfect possession of his senses. This is a point which the best physiologists acknowledge themselves unable to explain. It is quite impossible to believe, that in those moments during which a sleepwalker accomplishes some intellectual task which he found himself unable to get through when awake, his faculties of thought, of reasoning, of comparison, &c., should be dormant. Still the strange capability with which he seems to be endowed during sleep, resembles very much that form of insanity, in which a patient is mad upon every subject but one. Amongst the testimonies that are recorded as proving the existence of such examples, it is mentioned, that "some portions of a great national establishment for lunatics, were constructed from the plans of one of its unforunate

inmates, who, although his genius and his science were then so perfect in the subject of architecture, as to create designs of great brilliancy, was to all other intents and purposes insane." The sleep-walker has been known to cry, when his apparent intentions met with any impediments. Some very useful medical hints are given by Mr. Dendy, on the subject of somnambulism. The following remarks deserve general attention :

The want of uniformity in the appearances on examination of patients simply known to be sleep-walkers, is at present discouraging. In chorea, very frequently, and in the somnambulist, we have ascertained that, previous to the dance or the night walk, pain has been felt about the occiput, and in the course of the upper portion of the spinal marrow. In other cases, chorea will be produced during slumber by some agitating cause, or violent motion on the previous day. Patients are, from these causes, sometimes seized in bed with an irresistible rolling motion, and their actions, on such occasions, very closely resemble somnambulism. Although pain in the abdomen is seldom complained of in any of these diseases, yet there appears to be, from the influence which dyspepsia and other abdominal derangements exert over them, some peculiar sympathy excited between the ganglionic system, or the nerves of organic life and the brain, previous to the attacks. We cannot, at present, be prepared to impute the excitement of somnambulism always to diseased structure. I believe that conditions of much less importance will be sufficient to produce it where there is that peculiar irritability and tendency of mind.'-pp. 93, 94.

On the subject of reverie, Mr. Dendy observes that it is the name appropriated to the condition of the mind, when, though the eyes may act perfectly, there is no internal perception of the impression which objects may make on the retina. Here the organs of sight performs all its functions; but the mind is unconscious of the effects which are produced by its activity. Another species of reverie is that which will be best known under the homely title of the "brown study," denoting a morose disposition, and a liability to feel annoyance from trifling causes. In its mildest form, this species of transient delusion is well described by the short French word ennui, whilst the terms misanthropy, melancholy, and hypochondriasis, are employed to distinguish its severer symptoms. Mr. Dendy adds the following reflections:

The reverie is not, however, always confined to one subject; it may consist of a wandering of the imaginative faculty of mind,-of a train of ideas, between the links of which there is an intimate relation, but its beginning and end may appear so dissonant, that the absent person himself may fail to recognize the connection, until, by an effort of recollection, he is induced to retrace the steps of thought, and in this way the mystery is developed. Of this nature is the case, related by Bossuet, of one who, when quite awake, often saw landscapes and figures as plainly as if they were real. During this influence, we may often find that the features or corporeal actions shall prove an involuntary, though correct, index of the