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half-hour lecture, I went, not without some incredulity, to the smith's shop, with many other curious spectators, when we were eye-witnesses of the complete success of his art. This, too, had been a troop-horse, and it was supposed, not without reason, that after regimental discipline had failed, no other would be found availing. I observed that the animal seemed afraid whenever Sullivan either spoke or looked at him." In common cases, Mr. Townsend adds, even the mysterious preparation of a private interview was not necessary, the animal becoming tame at once. We have here, therefore, another instance of most extraordinary and instantaneous ascendency of one animal being over another, without any manifest medium of action, which we are occasionally, but not often, called upon to witness. That it could not have been force is clear; and though natural firmness and intrepidity may do much, they by no means appear to have been sufficient in the present case, and could, indeed, accomplish but little in the dark. Nor does there seem to be any mode of accounting for such a control so reasonable as that of a natural or artificial emanation from the fascinator, which we have already adverted to; and, if the last, obtained, perhaps, as in many of these instances, by illining or impregnating the person of the operator with the virtues of various plants unknown or little known to the rest of the world.

Thus far we may proceed safely upon the subject before us. But some theorizers have not rested satisfied here, and with much rhapsody of invention, have carried forward the same mysterious agency into the recesses of the intellect, and contended that it is by a similar kind of medium, or, sometimes, by a sort of elective attraction, operating invisibly through the moral world, as the imperceptible powers before us operate in the physical, that mind produces occasionally an instantaneous influence upon mind; whence, say they, we are at times impelled, by a certain indescribable sympathy, to feel more pleased with one person of less intellectual and perhaps even less moral worth, than with another person, whose endowments in both respects are confessedly superior: while others, pursuing the hallucination still farther, have gravely suggested, that it is possibly by some such medium that an intercourse is occasionally maintained between ourselves and the spirits of our departed friends; between this world and worlds around us. To hunt down such vagaries would indeed be a thriftless employment; and I only mention them to show that philosophy has its dreams and romances as well as history or even poetry; and that the principles of physics are as liable to perversion as those of ethics. Philosophy is a pilgrim, for the most part, of honest heart, clear foresight, and unornamented dress and manners; the genuine bride to whom heaven has betrothed him is Reason, of celestial birth and spotless virginity; and the fair fruit of so holy a union is truth, virtue, sobriety, and order. But should ever the plain pilgrim play the truant, as unfortunately in the present corrupt state of things we have reason to fear has too frequently proved a fact,-should ever Philosophy migrate from his proper hermitage, and in an hour of ebriety connect himself with the harlot Imagination, what can be the result of so unlicensed a dalliance but a spawn of monsters and miscreations; of hideous and unreal existences; of phantoms and will-o'-the-wisps, equally abhorred by God and man; treacherously hanging up their dim wildfire, in the pestilent bosom of mists and exhalations, and from their murky shades alluring the incautious inquirer to bogs and sloughs, and quagmires of wreck and ruin?

• Survey of the County of Cork, p. 438.

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LECTURE VII.

ON SLEEP, DREAMING, REVERY, AND TRANCE; SLEEP-WALKING, AND SLEEP-TALKING.

We are proceeding to a subject of much difficulty in theory, though of the greatest familiarity in fact; and I freely confess to you, that although I have endeavoured to investigate almost every opinion that has been offered upon it, from the time of Aristotle to our own day, I have never met with any thing in the least degree satisfactory, or capable of unravelling the perplexities in which it lies entangled.

What can possibly be more opposite to each other than the two states of wakefulness and sleep?-the senses in full vigour and activity, alive to every pursuit, and braced up to every exertion, and a suspension of all sense whatever, a looseness and inertness of the voluntary powers, so nearly akin to death, that nothing but a daily experience of the fact itself could justify us in expecting that we could ever recover from it.

And yet, while such is the lifelessness without, the mind, now destitute of the control of the will, is often overwhelmed with a chaos of ideas, rushing upon each other with so much rapidity, that the transactions of ages are crowded into moments, and so confused and disjointed, that the wildest and most incongruous fancies flit before us, and every thing that is possible becomes united with every thing that is impossible.

Such, however, are the ordinary means devised by Infinite Wisdom to revivify the animal frame when exhausted by the labours of the day; to recruit it for new exertions, and enable it to fill up the measure of its existence.

The order I shall take leave to pursue in discussing this abstruse subject will consist, first, in a brief examination of the more prominent hypotheses on sleep and dreaming that have been offered to us by ancient and modern schools: secondly, in a minute analysis of the feelings and phenomena by which these operations are characterized, agreeably to the series in which they occur thirdly, in submitting the outline of a new theory to explain the entire process: and, lastly, in an application of such theory to a variety of other subjects of a similar and equally extraordinary nature.

Sleep may be either natural or morbid. The former is usually produced by whatever exhausts the principle of life; as great muscular excitement, violent pain, vehement use of the external senses; or great mental excitement, as intense thought or severe distress. Morbid sleep is commonly occasioned by compression or commotion of the brain, and is hence often the result of congestion, plethora, or local injury to the skull.

Compression and commotion, though less frequent, are more direct and obvious causes: and hence the greater number of physiologists believe compression to take place, also, though in a slight degree, in every case of natural sleep; and in reality to constitute the immediate, while sensorial exhaustion only constitutes the remote, cause of this phenomenon. They appeal to the lethargic effect of a full stomach in infants, and of drunkenness in adults, which they refer to congestion in the brain, in consequence of a greater influx of blood into this organ: and hence they reason that a similar sort of pressure is produced by some means or other in every case of sleep. But what are the means of pressure thus referred to? And here a considerable difficulty is felt by every school of physiologists: and two distinct schemes are devised to get rid of it. By the one we are directed to the arterial system, which, we are told, becomes peculiarly excited and overcharged in the organ of the brain during wakefulness, from the activity of the internal By the other we are directed to the absorbent system, which from

senses.

This explanation is partly, though not chiefly, adopted by the author of the elaborate article on sieep, In Rees's Cyclopædia; and has since been fully embraced by Mr. Carmichael, in his learned Essay on

the same activity is said to become worn out and rendered torpid in the same organ; and, hence, to be incapable of carrying off the fine fluid which is perpetually exhaling from the secernent vessels into the ventricles of the brain.

Nothing, however, can be more unfounded than both these conjectures, and it is difficult to determine which of the two is the most so. But we are in no want of either of them, for we are in no want of the pressure which they are invented to account for. The principle of exhaustion alone will, I trust, be found sufficient to answer every purpose as a general cause of natural sleep; and, were it possible for us to add that of local pressure, the sleep would no longer be natural, but morbid.

Before we proceed farther, however, I will just hint that Dr. Cullen supposes the nervous fluid or power to be disposed by nature to an alternating state of torpor and mobility. He does not admit that it is ever exhausted and restored as a secretion;t and hence in sleep it is only suspended: and in consequence of this suspension the exercise of sense and volition is suspended, also. Narcotics do not, therefore, in his view, exhaust, but only suspend the nervous power or fluid, and thus induce sleep, which consists in such suspension. The apparently stimulant power of narcotics he derives from the vigilant exertion of the vis medicatrix naturæ,-the instinctive effort of nature to guard against such suspension of vital power as essentially mischievous, and, when carried to an extreme, fatal: and hence, narcotics are with him directly sedative, but only indirectly stimulant. He sup poses both sleep and waking to take place upon each other merely by a law of alternation: an explanation that will satisfy few.

But the chief attention of physiologists, both ancient and modern, has been directed to the subject of dreaming, which has usually but erroneously been regarded as a distinct process from that of sleeping. Let us next, therefore, as briefly as may be, and before we enter into a direct analysis of the phenomena that successively arise, take a glance at a few of the conjectures by which dreaming has hitherto been accounted for.

Among the Greek philosophers we meet with two explanations that are worthy of notice; that of Epicurus, because of its ingenuity, and that of Aristotle, because it has descended to the present times.

According to the Epicurean hypothesis of sensation, all the organs of external sense are stimulated to their appropriate functions, by the friction of an effluvium or emanation thrown off from the body perceived. This doctrine, which still holds good, and is uniformly employed in modern times to explain the senses of taste and smell, was equally extended by Epicurus to those of sight and hearing: the former being supposed to depend upon an effluvium of exquisitely fine films, images, or SPECIES, as they were technically called, perpetually issuing in every direction from every existing substance, somewhat in the manner in which snakes and grasshoppers cast off their skins annually, but almost infinitely finer, and altogether invisible. And as these rush against the eye, they were conceived to convey to it a perfect image of the object from which they are ejected. While sound was supposed to be excited in like manner by particles of a peculiar kind thrown off from the sonorous body, and rousing the ears by their appropriate stimulus.

These effluvia of every kind were conceived to be so exquisitely attenuate that they can pass, as light, heat, or electricity does, through a variety of solid bodies, without being destroyed in their passage. The effluvia or pellicles of vision were supposed not unfrequently to arise from the very bodies of those that have been long buried; and to be capable not only of transpiercing the soil in which they are inhumed, and of stimulating the organs of external sight, but of winding through the substance of the flesh, and of stimulating the soul itself in the interior of the animal frame, especially when

Dreaming. Sce Transactions of the Association of Fellows and Licentiates of the King's and Queen's College of Physicians in Ireland, vol. ii. p. 48, 8vo. 1819, Dubl. His explanation of dreaming is that of Gall and Spurzheim, which the reader will find adverted to subsequently.

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• Materia Medica, ii. 296.

↑ lb. p. 223.

+ Ib. p. 226.

in a state of sleep, in which the external sense is closed, or of deep abstraction, in which it is inattentive; and thus of presenting to the soul in its naked state, as it may be called, pictures of objects no longer in existence. And hence these philosophers, with great ingenuity, though, as it now appears, with great incorrectness, undertook to solve many of the most difficult problems in nature; accounted for the casual appearance of spectres in the gloom of solitude and retirement, and directly unfolded to the world the "stuff that dreams are made of."

It is needless to point out the errors of this system, for it has long sunk into disuse, never to rise again. And I shall therefore proceed to the rival hypothesis of Aristotle, which, though equally unfounded in fact, has been fortunate enough to descend to modern times, and to have met with very powerful advocates in M. Wolff* and M. Formey. It was the doctrine of Aristotle, that external sensations not only produce by their stimulus a variety of INTELLECTUAL FORMS or images in the sensory, somewhat similar to the ideas of Plato, and for all practical purposes not very dissimilar to what is meant by ideas in the present day, but that these forms or ideas are themselves capable of producing another set of forms or ideas, though of a more airy and visionary kind:

As every shadow has itself a shade.

And to this secondary set, these slighter and more attenuate pictures of things, he gave the name of PHANTASMS. In the opinion of this philosopher, dreams consist alone of these phantasms, or mere creatures of the imagination, first excited by some previous motion or sensation in the brain, and afterward continued in a more or less perfect series, according to the power of the imagination itself. The only difference I am able to trace between this theory, as started by Aristotle, and as restarted by Wolff, is in the greater regularity that the latter assigns to the phenomena of dreaming, than the former does: M. Wolff believing them to be, in their commencement, excited by a sensation, and in their succession and series of representations to be as much controlled by a peculiar system of laws, as the motions of the heavenly bodies. Formey appears to carry this point a little farther: his language is, if the dream be natural, it must necessarily originate agreeably to the law of sensation, and be continued by the law of imagination; and hence he concludes those dreams to be supernatural, which either do not begin by sensa tion or are not continued by the law of imagination.

It may be sufficient to remark upon this theory, first that the phantasms of Aristotle have as little claim to entity as the species of Epicurus; next, that the assumption of a code of laws, or rather of two distinct codes of laws, to regulate the fleeting train of our ideas in dreaming, is in itself altogether visionary and gratuitous; and that if the term chance or fortuitousness, a very useful term and full of meaning in all languages, can with propriety be applied to any thing, there is no subject to which it can be better applied than to that of dreaming; in which the will, the only legislator and controller of our ideas, has withdrawn its authority, and left the brain to a temporary lawlessness and misrule; and, lastly, that the distinction which is thus attempted to be drawn between natural and supernatural dreams is not only altogether fanciful, but could never be of any possible avail, even if well founded; for, in order to distinguish between the two, it would be necessary to be intiniately acquainted with those laws of sensation and imagination which are here stated to regulate our natural dreams, and the suspension of which produce dreams of a superior character.

We are touching upon a delicate, and, perhaps, a dangerous inquiry; but as it has been boldly handled in modern times, and made the foundation of a more daring speculation upon the subject, it must not be flinched from in our present discussion. That total absence of all natural law, which M. Formey

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supposes occasionally to take place in the act of dreaming, and to distinguish the supernatural from the natural vision, Mr. Andrew Baxter, and, since his time, Bishop Newton, conceive to take place in every instance of dreaming; and hence, that dreaming is at all times, and on all occasions, a supernatural operation. These excellent men divide dreams into two kinds, good and evil; and conceive two kinds of agents, good and evil spirits, employed in their production; and, consequently, account for the one or the other sort of dreams, in proportion as the one or other kind of agents obtains a predominancy.

Now it must be obvious that this conjecture is just as destitute of all tangible basis as either of the preceding; that it can make no appeal to facts submitted to the senses. But, beyond this, its very foundation-stone consists of a principle that no man can readily grant who maturely weighs its full import; namely, that dreaming is altogether an unnatural operation; that nearly onehalf of our lives is spent in a direct intercourse with invisible beings; and that during this moiety of his existence man is no longer a free agent; his whole train of thoughts and ideas being not loose and dismantled, but run away with by foreign compulsion, and the work of a demoniacal possession. The difficulties into which such an explanation throws its adherents are incalculable. Let us confine ourselves to one more example. There can be no doubt that other animals have their dreams as well as man, and that they have them as vigorous and as lively. Every one has beheld his favourite dog, while asleep by the fireside in the winter season, violently stretching out his limbs, howling aloud, and at times starting abruptly, beneath the train of images of which his dream is composed. In what manner will such philosophers account for these various phenomena? Is dreaming a natural operation? or are good and evil spirits the natural attendants upon dogs and cats, as well as upon mankind? The one or the other of these conclusions must follow; and there can be no difficulty in determining which of them will possess the general suffrage.

That dreams, like every other occurrence in nature, may occasionally become the medium of some providential suggestion, or supernatural communication, I am by no means disposed to deny. That they have been so employed in former times is unquestionable; and that they have been so employed occasionally among all nations in former times is highly probable; and the peculiar liveliness with which the trains of our dreaming ideas are usually excited, and from a cause which I shall presently endeavour to explain, seems to point out such a mode of communication as peculiarly eligible. But I am at present attending to the natural phenomena alone, and can by no means enter into a consideration of such foreign interference, which, as it certainly has been, may still therefore be, for all we can prove to the contrary, occasionally introduced into them.

In what may be called our own times, there are many valuable writers who have turned their attention to this curious subject, and who concur in the two following important positions: first, that the faculty, or at least the action, of the will is suspended during the influence of sleep: and, secondly, that in consequence of this suspension or discontinuance, the trains of ideas which persevere in rushing over the mind, are produced and catenated by that general habit of association which catenates them while we are awake. The power of the will, it is contended, is not necessary to the existence of ideas, which, therefore, may continue while such power is in a state of abeyance; but which, if they continue at all, must take the general order and succession imprinted upon them by the law of association, excepting in cases in which such law is broken in upon a variety of incidental circumstances, as uneasiness arising from a surcharged stomach, or other bodily sensations.

Such are the two fundamental principles upon which the theories of Hartey, Darwin, and Dugald Stewart, are respectively built; and which, in various ways, and with almost equal ingenuity, they seem very satisfactorily to

An Inquiry into the Nature of the Human Soul, wherein the Immortality of the Soul is evinced from the Principles of Reason and Philosophy, 4to 1730

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