new and curious remarks, but would contribute to diminish that blind admiration of original genius, which is one of the chief obstacles to the improvement of science.

The history of natural philosophy, before and after the time of Lord Bacon, affords another proof, how much the powers of invention and discovery may be assisted by the study of method: and in all the sciences, without exception, whoever employs his genius with a regular and habitual success, plainly shows, that it is by means of general rules that his inquiries are conducted. Of these rules, there may be many which the inventor never stated to himself in words; and perhaps he may even be unconscious of the assistance which he derives from them; but their influence on his genius appears unquestionably from the uniformity with which it proceeds; and in proportion as they can be ascertained by his own speculations, or collected by the logician from an examination of his researches, similar powers of invention will be placed within the reach of other men, who apply themselves to the same study.

The following remarks, which a truly philosophical artist has applied to painting, may be extended, with some trifling alterations, to all the different employments of our intellectual powers:

"What we now call genius, begins, not where rules, abstractedly taken, end; but where known, vulgar, and trite rules have no longer any place. It must of necessity be, that works of genius, as well as every other effect, as it must have its cause, must likewise have its rules; it cannot be by chance, that excellences are produced with any constancy, or any certainty, for this is not the nature of chance; but the rules by which men of extraordinary parts, and such as are called men of genius, work, are either such as they discover by their own peculiar observation, or of such a nice texture as not easily to admit handling or expressing in words.

"Unsubstantial, however, as these rules may seem, and difficult as it may be to convey them in writing, they are still seen and felt. in the mind of the artist; and he works from them with as much certainty, as if they were embodied, as I may say, upon paper. It is true, these refined principles cannot be always made palpable, like the more gross rules of art; yet it does not follow, but that the mind may be put in such a train, that it shall perceive, by a kind of scientific sense, that propriety which words can but very feebly suggest."-(Discourses by Sir Joshua Reynolds.)

SECTION V.

Application of the principles stated in the foregoing sections of this chapter, to explain the Phenomena of Dreaming.

With respect to the phenomena of dreaming, three different questions may be proposed. First, What is the state of the mind in sleep? or, in other words, what faculties then continue to operate, and what faculties are then suspended? Secondly, How far

do our dreams appear to be influenced by our bodily sensations: and in what respects do they vary, according to the different conditions of the body in health, and in sickness? Thirdly, What is the change which sleep produces on those parts of the body, with which our mental operations are more immediately. connected; and how does this change operate, in diversifying so remarkably the phenomena which our minds then exhibit, from those of which we are conscious in our waking hours? Of these three questions, the first belongs to the philosophy of the human mind; and it is to this question that the following inquiry is almost entirely confined. The second is more particularly interesting to the medical inquirer, and does not properly fall under the plan of this work. The third seems to me to relate to a subject, which is placed beyond the reach of the human faculties.

It will be granted, that, if we could ascertain the state of the mind in sleep, so as to be able to resolve the various phenomena of dreaming into a smaller number of general principles; and still more, if we could resolve them into one general fact, we should be advanced a very important step in our inquiries upon this subject; even although we should find it impossible to show, in what manner this change in the state of the mind results from the change which sleep produces in the state of the body. Such a step would at least gratify, to a certain extent, that disposition of our nature which prompts us to ascend from particular facts to general laws; and which is the foundation of all our philosophical researches; and, in the present instance, I am inclined to think, that it carries us as far as our imperfect faculties enable us to proceed

In conducting this inquiry with respect to the state of the mind. in sleep, it seems reasonable to expect, that some light may be obtained from an examination of the circumstances which accelerate or retard its approach; for when we are disposed to rest, it is natural to imagine, that the state of the mind approaches to its state in sleep, more nearly, than when we feel ourselves alive and active, and capable of applying all our various faculties to their proper purposes.

In general, it may be remarked, that the approach of sleep is accelerated by every circumstance which diminishes or suspends the exercise of the mental powers; and is retarded by every thing which has a contrary tendency. When we wish for sleep, we naturally endeavor to withhold, as much as possible, all the active exertions of the mind, by disengaging our attention from every interesting subject of thought. When we are disposed to keep awake, we naturally fix our attention on some subject which is calculated to afford employment to our intellectual powers, or to rouse and exercise the active principles of our nature.

It is well known, that there is a particular class of sounds which compose us to sleep. The hum of bees; the murmur of a fountain; the reading of an uninteresting discourse, have this tendency in a

remarkable degree. If we examine this class of sounds, we shall find that it consists wholly of such as are fitted to withdraw the attention of the mind from its own thoughts, and are, at the same time, not sufficiently interesting to engage its attention to themselves.*

It is also matter of common observation, that children and persons of little reflection, who are chiefly occupied about sensible objects, and whose mental activity is, in a great measure, suspended, as soon as their perceptive powers are unemployed; find it extremely difficult to continue awake, when they are deprived of their usual engagements. The same thing has been remarked of savages, whose time, like that of the lower animals, is almost completely divided between sleep and their bodily exertions.†

From a consideration of these facts, it seems reasonable to conclude, that in sleep those operations of the mind are suspended, which depend on our volition; for if it be certain, that before we fall asleep, we must withhold, as much as we are able, the exercise of all our different powers; it is scarcely to be imagined, that, as soon as sleep commences, these powers should again begin to be exerted. The more probable conclusion is, that when we are desirous to procure sleep, we bring both mind and body, as nearly as we can, into that state in which they are to continue after sleep commences. The difference, therefore, between the state of the mind when we are inviting sleep, and when we are actually asleep, is this, that in the former case, although its active exertions be suspended, we can renew them, if we please. In the other case, the will loses its influence over all our powers both of mind and body ; in consequence of some physical alteration in the system, which we shall never, probably, be able to explain.

In order to illustrate this conclusion a little farther, it may be proper to remark, that if the suspension of our voluntary operations in sleep be admitted as a fact, there are only two suppositions which can be formed concerning its cause. The one is, that the power of volition is suspended; the other, that the will loses its influence over those faculties of the mind, and those members of the body, which, during our waking hours, are subjected to its authority. If it can be shown, then, that the former supposition is not agreeable

Lord Bacon has taken notice of this fact; and the account he has given of it (so far as it relates to the power of attention) is not very wide of the truth. His theory concerning "the Motion of the Spirits," furnishes a proof of the proneness of those men who are the most fully aware of the importance of experiment and observation in physics, to indulge in hypotheses, in explaining the phenomena of the human mind. "Some noises help sleep, as the blowing of wind, and the trickling of water; they move a gentle attention, and whatsoever moveth attention, without too much labor, stilleth the natural and discursive motion of the spirits."

"The existence of the negro slaves in America, appears to participate more of sensation than reflection. To this must be ascribed, their disposition to sleep when abstracted from their diversions and unemployed in their labor. An animal whose body is at rest, and who does not reflect must be disposed to sleep of course." -Notes on Virginia, by Mr. Jefferson, p. 225.

to fact, the truth of the latter seems to follow as a necessary conse

quence.

1. That the power of volition is not suspended during sleep, appears from the efforts which we are conscious of making while in that situation. We dream, for example, that we are in danger; and we attempt to call out for assistance. The attempt, indeed, is, in general, unsuccessful; and the sounds which we emit are feeble and indistinct; but this only confirms, or rather is a necessary consequence of the supposition, that, in sleep, the connexion between the will and our voluntary operations is disturbed or interrupted. The continuance of the power of volition is demonstrated by the effort, however ineffectual.

In like manner, in the course of an alarming dream, we are sometimes conscious of making an exertion to save ourselves, by flight, from an apprehended danger; but in spite of all our efforts we continue in bed. In such cases, we commonly dream that we are attempting to escape, and are prevented by some external obstacle; but the fact seems to be, that the body is, at that time, not subject to the will. During the disturbed rest which we sometimes have when the body is indisposed, the mind appears to retain some power over it; but as, even in these cases, the motions which are made consist rather of a general agitation of the whole system, than of the regular exertion of a particular member of it, with a view to produce a certain effect; it is reasonable to conclude, that in perfectly sound sleep, the mind, although it retains the power of volition, retains no influence whatever over the bodily organs.

In that particular condition of the system, which is known by the name of incubus, we are conscious of a total want of power over the body; and, I believe, the common opinion is, that it is this want of power which distinguishes the incubus from all the other modifications of sleep. But the more probable supposition seems to be, that every species of sleep is accompanied with a suspension of the faculty of voluntary motion, and that the incubus has nothing peculiar in it but this, that the uneasy sensations which are produced by the accidental posture of the body, and which we find it impossible to remove by our own efforts, render us distinctly conscious of our incapacity to move. One thing is certain, that the instant of our awaking, and of our recovering the command of our bodily organs, is one and the same.

2. The same conclusion is confirmed by a different view of the subject. It is probable, as was already observed, that when we are anxious to procure sleep, the state into which we naturally bring the mind, approaches to its state after sleep commences. Now it is manifest, that the means which nature directs us to employ on such occasions, is not to suspend the power of volition, but to suspend the exertion of those powers whose exercise depends on volition. If it were necessary that volition should be suspended before we fall asleep, it would be impossible for us, by our own

efforts to hasten the moment of rest. The very supposition of such efforts is absurd; for it implies a continued will to suspend the acts of the will.

According to the foregoing doctrine with respect to the state of the mind in sleep, the effect which is produced on our mental operations, is strikingly analogous to that which is produced on our bodily powers. From the observations which have been already made, it is manifest that in sleep, the body is, in a very inconsiderable degree, if at all, subject to our command. The vital and involuntary motions, however, suffer no interruption, but go on as when we are awake, in consequence of the operation of some cause unknown to us. In like manner, it would appear, that those operations of the mind which depend on our volition are suspended; while certain other operations are, at least, occasionally carried on. This analogy naturally suggests the idea, that all our mental operations, which are independent of our will, may continue during sleep; and that the phenomena of dreaming may, perhaps, be produced by these, diversified in their apparent effects, in consequence of the suspension of our voluntary powers.

If the appearances which the mind exhibits during sleep are found to be explicable on this general principle, it will possess all the evidence which the nature of the subject admits of.

It was formerly shown, that the train of thought in the mind does not depend immediately on our will, but is regulated by certain general laws of association. At the same time, it appeared, that among the various subjects which thus spontaneously present themselves to our notice, we have the power of singling out any one that we choose to consider, and of making it a particular object of attention; and that by doing so, we not only can stop the train that would otherwise have succeeded, but frequently can divert the current of our thoughts into a new channel. It also appeared, that we have a power (which may be much improved by exercise) of recalling past occurrences to the memory, by a voluntary effort of recollection.

The indirect influence which the mind thus possesses over the train of its thoughts is so great, that during the whole time we are awake, excepting in those cases in which we fall into what is called a reverie, and suffer our thoughts to follow their natural course, the order of their succession is always regulated more or less by the will. The will, indeed, in regulating the train of thought, can operate only (as I have already shown) by availing itself of the established laws of association: but still it has the power of rendering this train very different from what it would have been, if these laws had taken place without its interference.

From these principles, combined with the general fact which I have endeavored to establish, with respect to the state of the mind in sleep, two obvious consequences follow: first, That when we are in this situation, the succession of our thoughts, in so