control and power we have over our thoughts, nor can we dismiss, and throw off, an unpleasant train of thought, a disagreeable impression, however much we may desire to be rid of it. We are at the mercy of our own thoughts and casual associations, which, in the ungoverned, sponta neous play of the mind's own inherent energy, and guided only by its own native laws, produce the wildest and stran gest phantasmagoria, having to us all the semblance of reality, while we are, in truth, mere passive spectators of the scene.

Faculties of Mind not suspended in Sleep. It has been supposed by some that the faculties of the mind are, in part or wholly, suspended in sleep, especially the higher faculties more immediately dependent on the will. So long as mental activity goes on, however, - and there is no evidence that it ever entirely ceases in sleep so long there is thought, and so long must that thought and activity be exerted in some particular direction, and on some particular object. We cannot conceive of the mind as acting or thinking, and not exercising any of its faculties, for what is a faculty of the mind but its capacity of acting in this or that way or mode, and on this or that class of subjects. It may be perception, or conception, or memory, or imagination, or judgment, or reasoning, or any other faculty that is for the moment active; it must be some one of the known faculties of the mind, unless, indeed, we suppose some new faculties to be then developed, of whose existence we are at other times unconscious.

Mental Action modified by certain Causes in Sleep. The faculties will, however, be materially modified in their action during sleep, by the causes already named; chiefly these two: 1st. the entire suspension of voluntary control over the train of thought; 2d. the loss of personal consciousness as regards especially the bodily organization, and its present relations to time, and space, and all sensible objects, In consequence of the former our thoughts will come and

go all unregulated and disconnected; there will be no co herence; the slightest analysis will suffice for the associating principle; we shall be hurried on and borne away on the rushing tide of thought, as a frail passive leaf swept on the bosom of the rapids; we shall whirl hither and thither as in the dance of the witches; we shall waken in confusion, and seek to recover the reins of self-control, only to lose them again and be swept on in the fearful dance.

In consequence of

Want of Congruity owing to what. the latter cause - the loss of sensational consciousness and of our relations to sensible objects—there will be an entire want of fitness and congruity in our mental operations. The laws of time, and space, and personal identity, will be altogether disregarded, and we shall not be conscious of the incongruity, nor wonder at the strangest and most contradictory combinations. Here, there, everywhere, now this and now that. The scene is in the valley of the Connecticut, and anon on the Ural mountains, or the desert of Arabia, and we do not notice the change as any thing at all remark. able. Now we are walking up the aisle of the church, in garments all too scanty for the proprieties of the occasion, and now it is a wild bull that is racing after us, and the transition from one to the other is instantaneous. Why should it not be, for it is by the senses alone that we are brought into conscious relation to the external world, and so made cognizant of the laws of time and space, and those senses being now locked in oblivion, what are time and space to us?

The Causes now named a sufficient Explanation of the Phenomena. The causes already named will sufficiently account for the strange and distorted action of the various mental faculties as exercised in sleep. Memory, e. g., will give us the past with variations ad libitum; things will appear to us, and events will seem to transpire, and forms and faces familiar will look out upon us, not as they really are, or ever We talk with a former friend, without the thought

once occurring to us that he has been dead these many years. Impression there is, feeling, idea, fancy, association of all these, but hardly memory, or even imagination, much less judgment or reasoning. So it would seem at first. A closer inspection, however, will show us that there is in reality, in this spontaneous play of the mind, the exercise of all these faculties, only so modified by causes now named as to present strange and uncouth results.

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Mental Faculties not immediately dependent on the Will. - If any of the mental faculties can be shown to be entirely dependent on the will for their activity and operation, so as to have no power to act except by its order or permission, then it would follow that when the will is no longer in possession of the throne, when its sway is for the time suspended as in sleep, the faculties thus dependent on it must lie inactive. But with regard to most if not all mental operations, we know the reverse to be true. They are capable of spontaneous, as well as voluntary action. Nay, some of them, it would seem, are not subject, in any case, directly to its control. It is not at our option whether to remember or forget, whether to perceive surrounding objects, whether such or such a thought shall, by the laws of association, follow next in the train of ideas and impressions. Some mental operations are more closely connected with and admit of a more direct interference on the part of the will than others, but it cannot be shown, I think, that any faculty is so far dependent on the will as not to be capable of action, irrespective of its demands. Indeed, facts seem to show that where once a train of mental action has been set in opera tion by the will, that action goes on, for a time, even when the will is withdrawn, or held in abeyance, as in sleep, or profound reverie.

Whence this Suspension of Power of the Will. - The question may occur, whence arises this suspension of the power of the vill over the mental operations in sleep? What produces it? Does it, like the loss of voluntary power over

the physical frame, result from the inactivity of the nervous apparatus? The fact that it always accompanies this, and is found in connection with it, that whatever produces the latter seems to be the occasion, also, of the former, as in the case of disease, delirium, mesmeric influence, stupefying drugs, inebriation, etc., and that the degree of the one, whether partial or complete, is in proportion to the degree of the other-these facts seem to me to favor the idea now suggested.

Summary of Results.

These, then, seem to be the principal phenomena of sleep: loss of sensational consciousness, loss of voluntary power over the body, loss of voluntary power over the operations of the mind.

Exhaustion of the nervous System. — Sleep, then, appears to be primarily an affection of the nervous system, the result of its exhaustion. By the law of nature, it cannot continue always active; repose must succeed to effort. Hence, the more rapid the exhaustion of the nervous system, from any cause, the more sleep is demanded. This we know to be the fact. The more sensitive the system, as in childhood, or with the gentler sex, as in men of great sensibility also, poets, artists, and others, the more sleep. On the other hand, those sluggish natures which allow nothing to excite or call into action the nervous system, sleep from precisely the opposite cause; not the exhaustion of nervous activity, but its absolute non-existence. If both our systems, the animal and the vegetative or nutritive, should sleep at once, says Rauch, there would be nothing to awaken us. That would be death. "In sleep, every man has a world of his own," says Heraclitus; "when awake, all men have one in common." Sleeping and waking, it has been beautifully said by another, are the ebb and flood of mind and matter on the ocean of our life.

§ II.-DREAMS.

Resume of previous Investigation. It has been shown in the preceding section, that sleep is primarily and chiefly an affection of the nervous system, in which, through exhaustion, the senses become inactive, and, as it were, dead, while, at the same, the nutritive system and the functions essential to life go on; that in consequence of this inactivity of the sensorium, there results, 1. Loss of consciousness, so far, at least, as regards all connection with, and relation to, external things; 2. Loss of voluntary power over the physi cal and muscular frame; 3. Loss of voluntary control over the operations of the mind; the mind still remaining active, however, and its operations going on, uncontrolled by the will.

We are now prepared to take up, more particularly, that specific form of mental activity in sleep, called dreaming; a state which admits of easy explanation on principles already laid down.

A Dream, what. - What, then, is a dream? I reply, it is any mental action in sleep, of which, for any reason, we are afterward conscious. This is not the case with all, perhaps, with most mental action during sleep. Senses and the will are inactive, then, for the most part, and whatever thoughts and impressions may be wrought out in the laboratory of the mind, whatever play of forces and wondrous alchemy may there be going on, when the controlling principle that pre sides over and directs its operations is withdrawn, are, for the most part, never subsequently reported. Let the sensitivity be partially aroused, however, let some disturbing cause come in to prevent entire loss of sensibility, or let the conceptions of the mind present themselves with more than usual vividness and force of impression, and what we then think may afterward be remembered. This is the philosophy of dreams. What is thus remembered of our thoughts in sleep, we call a dream, more especially applying the term to Bch of our thoughts and conceptions in sleep, as have som