Графични страници
PDF файл
[blocks in formation]

The question whether we ever sleep without dreaming—as old as the days of Aristotle-is equally curious and difficult of solution. In support of the theory that no moment of sleep is void of dreaming thoughts or sensations, we have such names as Hippocrates, Leibnitz, Descartes, Cabanis. The most formidable authority on the opposite side is Locke. But that eminent man evidently had not before him all the phenomena necessary to afford a proper understanding of this subject. His definition of dreaming is faulty,* and the argument with which he supports his views, namely, that “man cannot think at any time, waking or sleeping, without being sensible of it," + evidently does not reach the case.

Of more modern writers, Macnish and Carpenter conclude that perfectly sound sleep is dreamless; while Holland, Macario, and (as far as they express themselves) Abercrombie and Brodie, assume the opposite ground. Plausible reasons may be adduced for either opinion.

Whatever be the conditions of that mysterious mechanism which connects the immaterial principle in man with the brain, this we know: that throughout waking life cerebral action of some kind is the necessary antecedent, or concomitant, of thought. This action, in some modified form, appears to continue at least during those periods of sleep when there occur dreams of such a character that they are remembered, or that their presence is testified by outward signs of emotion in the sleeper.

Dr. Perquin, a French physician, has reported the

* His definition is, “ Dreaming is the having of ideas, whilst the outward senses are stopped, not suggested by any external object or known occasion, por under the rule and conduct of the understanding."

But, wbile dreaming, the outward senses are, in general, only partially stopped ; ideas are often suggested by external objects and by physical sen. sations; and sometimes the understanding, instead of being dethroned, acquires a power and vivacity beyond what it possesses in the waking state.

† “An Essay concerning Human Understanding" Book II. chap. i. p. 10.



case of a female, twenty-six years of age, who had lost by disease a large portion of her skull-bone and dura mater, so that a corresponding portion of the brain was bare and open to inspection. He says, “When she was in a dreamless sleep her 'brain was motionless, and lay within the cranium. When her sleep was imperfect, and she was agitated by dreams, her brain moved, and protruded without the cranium, forming cerebral hernia. In vivid dreams, reported as such by herself, the protrusion was considerable; and when she was perfectly awake-especially if engaged in lively conversation-it was still greater. Nor did the protrusion occur in jerks alternating with recessions, as if caused by the impulse of the arterial blood. It remained steady while conversation lasted."*

Here we have three separate mental states, with the corresponding cerebral action intimated, so far as external indications are a clew to it: the waking state, in which the brain gives sign of full activity; a state known to be dreaming, during which there is still cerebral action, but in a diminished degree; and a third state, exhibiting no outward proof of dreaming, nor leaving behind any remembrance of dreams, and during which cerebral action is no longer perceptible to the spectator.

But we stretch inference too far if we assert, as some physiologists dont that in this third state there is no cerebral action and there are no dreams.

All that we are justified in concluding is, that, during this period of apparent repose, cerebral action, if such

* This case was observed in one of the hospitals of Montpellier, in the year 1821. It is by no means an isolated one. Macnish quotes it in his Philosophy of Sleep."

† Carpenter (“ Principles of Human Physiology," p. 634) is of opinion that during profound sleep the cerebrum and sensory ganglia are "in a state of complete functional inactivity."



continue, is much diminished,* and dreams, if dreams there be, are disconnected, by memory or otherwise, from our waking life.

If we push our researches further, and inquire what is the state of the soul, and what the conditions of its connection with the cerebrum, during the quiescent state, we are entering a field where we shall meet a thousand speculations, and perhaps not one reliable truth beyond the simple fact that, while life lasts, some connection between mind and matter must be maintained. We may imagine that connection to be intermediate only,-kept up, it may be, directly with what Bichât calls the system of organic life, and only through the medium of that system, by anastomosis, or otherwise, with the system of animal life and its center, the cerebral lobes; or we may suppose the connection still to continue direct with the brain. All we know is that, at any moment, in healthy sleep, a sound more or less loud, a touch more or less rude, suffices to restore the brain to complete activity, and to re-establish, if it ever was interrupted, its direct communication with the mind.

The Cartesian doctrine that the soul never sleeps is incapable alike of refutation and of practical applica

* Cases of catalepsy, or trance, in which for days no action of the heart or lungs is cognizable by the senses of the most experienced physician, so that actual death has been supposed, are of common occurrence; yet no one concludes that, however deep the trance, the heart has ceased to beat, or the lungs to play. Their action is so much enfeebled as to have become imperceptible: that is all.

+ See Récherches physiologiques sur la Vie et la Mort,” par X. Bichất, 3d ed., Paris, 1805, p. 3.

His division of the animal functions is into two classes: those of organic life and those of animal life; the first including the functions of respiration, circulation, nutrition, secretion, absorption, the instinctive or automatio functions common to animal and vegetable life; the second restricted to animal life alone, and including the functions which connect man and animals with the external world, -as of sensation, volition, vocal expression, and locomotion.

[ocr errors]



tion. If we imagine that the soul has need of rest, we must admit, as a corollary, that sleep is a phenomenon that will be met with in the next world as it is in this. If, on the other hand, we assert that there can be no moment in which an immortal spirit has not thoughts and sensations, it may be replied that the words thought and sensation, when used by human beings in regard to their present phase of life, properly apply only to mental conditions which presuppose the action of the human brain; and that, as to the action of the soul without the action of the brain, if such a state can be while the soul is connected with the body, it evinces lack of wisdom to occupy ourselves about it. We can predicate nothing in regard to it; not having in our human vocabulary even the words necessary to embody any conceptions of its phenomena.

Thus, even when we admit that it is the bodily organs only, not the spiritual principle, that experience a sense of fatigue and the necessity for intermittence of action, we do not concede, by the admission, that dreams, in the proper acceptation of the term, pervade all sleep

We approach a solution more closely when we inquire whether, as a general rule, persons who are suddenly awakened from a profound sleep are, at the moment of awaking, conscious of having dreamed. But here physiologists are not agreed as to the facts. Locke appears to have assumed the negative. Macnish declares, as the result of certain experiments made on purpose, that in the majority of cases the sleeper retained at the moment of waking no such consciousness.* This I much doubt. It is certain that, unless such experiments are conducted with scrupulous care, the true results may readily escape us. If, two years ago, I had myself been


* Hazlitt, in his "Round Table," alleges the contrary.



asked whether I was in the habit of dreaming, I should have replied that I very rarely dreamed at all; the fact being then, as it still is, that I scarcely ever have a dream which I remember, or could repeat, even at breakfast the next morning. But my attention having been recently attracted to the subject, so that I acquired the habit of taking special note of my sensations at the moment of awaking, I became aware, after repeated observations, that in every instance I was conscious of having dreamed. Yet, with very few exceptions, the memory of my sleeping thought was so vague and fugitive, that even after ten, or perhaps five, seconds, it had faded away, and that so completely that I found it quite impossible to recall or repeat my dream. After that period I remembered nothing, except that I had been conscious of having dreamed; and, to obtain in every case the certainty even of this, I had to awake with the intention of making the observation. So exceedingly brief and shadowy and fleeting were these perceptions, that in the great majority of cases no effort I could make sufficed to arrest them. They escaped even at the moment I was endeavoring to stamp them on my memory.

It is true that these observations were usually made at the moment of awaking, naturally, from a night's sleep, and that the strongest advocates of the theory of dreamless sleep (as Lord Brougham, in his Discourse on Natural Theology'') admit that the imperfect sleep bordering on the waking state is full of dreams. But yet the reality in connection with sleeping thoughts of a memory so feeble and evanescent that it requires an intentional effort to detect its existence, should induce us to receive with many scruples the assertions of those who declare that they have no dreams.*

* As of a young man, mentioned by Locke, (Essay on "Human Under. standing,Book II. chap 1. & 14,) a scholar with no bad memory, who de

« ПредишнаНапред »