A Monograph on Sleep and Dream: Their Physiology and Psychology

CHAPTER I.. What Sleep Is.

WHAT SLEEP IS.

Sleep is necessary to the health of the human organism. The Mechanism of Man depends for its sustainment and reparation upon recurring seasons of rest.

The condition of sleep is probably a requirement of organic structure. So far as we can trace it, all animal life sleeps. There is almost conclusive evidence that vegetable life sleeps also.

In this respect organic structure differs from inorganic structure. Minerals do not sleep. Only things that have life sleep. Wheresoever life is there is probably (it is not proved) a conscious individuality that “goes to sleep.” As sleep seems, so far as we can trace it, to be an attendant upon consciousness, a requirement, in fact, of nerve structure, the sleep of vegetable life would appear to indicate the presence of consciousness.

But sleep is not a suspension of vital action. The processes conducted by the vital force continue their work in sleep often more vigorously. The intelligence, also, is not wholly suspended in sleep. The functions of nutrition are performed even more perfectly than in the waking state. Rest appears to be required mainly for the muscular structure and for the nerve system that moves the muscles. The senses are often wholly, always partially, sealed in sleep. But it is doubtful if this be the result of a requirement for rest by the senses. The more probable inference is that the suspension of the senses is necessary to the suspension of muscular action.

Sleep, therefore, may be defined in general terms as the suspension, more or less perfect, of the action of the external senses, so that they cease to convey vividly to the mind the impressions made upon them. The action of the Will is likewise suspended, so that it ceases to convey the commands of the mind to the body. Thus is the rest procured that is required for the body.

The entire mechanism of the body and mind does not sleep, but only a part of it. In sleep the body performs all functions necessary for its continued healthy being. The mind dreams. The consciousness of the Individual Self is awake, for we note our dreams as they occur, believe that we are acting them and remember them afterwards.

CHAPTER II.. The Physiology of Sleep.

THE PHYSIOLOGY OF SLEEP.

Various conjectures have been advanced as to the precise physiological change that attends the condition of sleep. Some have located the source of sleep in the heart and others in the head. It was formerly a favourite theory that the action of the heart slackened and then the blood, flowing slowly through the brain, caused a kind of congestion there. This was, in fact, to look upon sleep as a species of coma that produced unconsciousness by pressure upon the fibres of the brain.

The later and better opinion is, that sleep is produced by the reverse of this process; that it is not a state of congestion but of collapse; that the blood flows from the part of the brain that sleeps, which is thus left in a state of depletion, with a consequent collapse of the brain fibres.

Observation of the actual brain of a man who had been trepanned and over a part of whose brain a movable silver plate was placed entirely confirmed this conjecture. In sleep, the convolutions of his brain were depressed; when awake, they resumed their normal form; when his mind was exerted, they swelled visibly.

Any reader who has been suddenly wakened may recal a sensation as of swelling of the brain by the blood rushing into it. This sensation was probably the result of the rapid erection of the flaccid brain fibres.

Other facts strongly support this theory. When the action of the heart is stimulated by any excitement, mental or bodily, sleep will not come. So long as the brain is busy we court sleep in vain. To induce sleep we apply remedies that tend to draw the blood from the brain to the extremities. A full meal engenders sleep; but not, as formerly supposed, by congesting the brain, but by attracting the blood to the stomach and so depleting the brain. Rapid motion in a cold wind causes drowsiness when warmth is restored. Why? The blood is borne swiftly back to the surface of the body and quits the brain. Many other instances will readily occur to the reader.

Note in another the process of “falling sleep.” The eyes move more and more slowly, the eyelids descend, the head nods and droops, the limbs relax, the book falls from the hand. Usually, before positive sleep occurs, involuntary endeavours at resistance are made. The eyes open with a stare. Consciousness is regained with an effort and a start. The thread of waking thought is resumed. But it is for a moment only. Again the head nods, the eyes blink and close, the limbs relax. He is asleep.

What are our own sensations when we go to sleep? Thought wanders. Ideas come straying into the mind unbidden and with no apparent association. External objects grow dim to the eye and sounds fall faint upon the ear. The communications of the senses to the brain are dull and uncertain. We are conscious that the power of the Will is relaxed. We strive to retain it. We recover it by an effort. We resume the work on which we were engaged. Vain the struggle. The thoughts wander still. The unbidden pictures flit again before the mind’s eye. We are conscious of the relaxation of the limbs and the closing of the eyelids. Then we cease to be conscious of external existence. We sleep.

But we are not conscious of the act of falling asleep—for itself is a suspension of consciousness. With some sleepers sleep is, as they affirm, a condition of entire unconsciousness. These tell us they have no sense of existence until the moment of waking and that, however protracted their slumber, the moment of waking is to them as the moment after having fallen asleep. It is impossible to contradict those who thus affirm, for their mental condition in sleep cannot be read. But if a judgment may be formed from their actions in sleep, as talking and motions of the limbs, the probable explanation will be that they dream but do not remember their dreams. All dreams vanish from their memories as some dreams vanish from the memories of those who habitually dream.

If we observe the aspect of a sleeper, we note the features placid, the breathing regular, the pulse soft and even, the limbs relaxed, the skin moist. Occasionally there are quiverings of the limbs and expressions of the face which betray the presence of mental emotions.

This is the physiological condition of Sleep.

We turn now to its mental condition.

CHAPTER III.. The Mental Condition of Sleep.

THE MENTAL CONDITION OF SLEEP.

Of all the phenomena exhibited in Psychology and Mental Physiology there is none more marvellous than that which is presented to every one of us every night. It only does not astonish us because it is so familiar. Perhaps the reason why so few have given a moment of reflection to its marvels is because they are seen so often. When the attention of the reader is more closely invited to these phenomena he will doubtless be surprised to find what a world of wonder is opened to him.

The passage from waking to sleeping is momentary. The closest observer of his own mental action fails to note it. But what a change is made in that moment! A complete mental revolution has been effected. The man himself has changed entirely. He has ceased to be a rational being! He is almost wholly severed from the external world, which exists for him no longer! His Will (which is the name we give to the expression of the Conscious Self) is paralysed. He has ceased to command his thoughts and his emotions. He has no control over his limbs. With the sole exception that he dreams, he is but a breathing clod. Of the forces that move his Mechanism, Life alone is active, working steadily and harmoniously as before. As we shall presently see, the other forces that move and direct the mechanism—the forces of Mind and Soul—are not inactive. But they have withdrawn from their waking work. They exist and their existence is manifest. But they have ceased to control and the mechanism has ceased to obey.

Some proof this—is it not?—that these Psychic Forces are distinct from the vital force and from the physical forces and have another origin. These phenomena of sleep supply further and most cogent evidence of the fallacy of the contention of the Materialists, that the vital force alone governs the mechanism of Man, and that all the forces that direct the mechanism are generated within the machine.

In sleep the vital force continues to do its normal work. At the same moment some other force or forces are engaged in doing abnormal work, thus establishing the fact that some force or forces, other than the vital force or the physical forces, are employed in moving the mechanism of Man.

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