Abbildungen der Seite
PDF
EPUB

CHAPTER IX.

SLEEPLESSNESS.

SLEEP takes place as soon as the sensorial power that keeps the brain awake is expended, which, under common circumstances, occurs at our ordinary hour of going to rest, or even sooner, if any soporific cause sufficiently strong should chance to operate. But the above power may be increased by various means, as in cases of physical suffering, or excited imagination, and, consequently, is not expended at the usual time. In this case, the person remains awake, and continues so till the period of its expenditure, which may not happen for several hours after he lies down, or even not at all, during the whole of that night. Now, whatever increases the sensorial power, whether it be balls, concerts, grief, joy, or bodily pain, is prejudicial to repose. By them the mind is exalted to a pitch of unnatural action, from which it is necessary it should descend before it can roll into the calm channel of sleep.

Whatever stimulates the external senses, however slightly, may prevent sleep. Thus, the tick

ing of a clock has this effect with very sensitive people; and a candle burning in the chamber is attended with the same result. Even when the eyes are shut this may take place, for the eye-lids are sufficiently transparent to transmit a sense of light to the retina. For the same reason, the light of day peering in at the window may awake us from or prevent slumber. It is said that Napoleon could never sleep if exposed to the influence of light, although, in other circumstances, slumber appeared at his bidding with surprising readiness.

A constitutional restlessness is sometimes brought on by habitually neglecting to solicit sleep when we lie down, by which means the brain is brought into such a state of irritability, that we can hardly sleep at all. Chronic wakefulness, originating from any mental or bodily affection, sometimes degenerates into a habit, in which the sufferer will remain for weeks, months, or even years, if authors are to be believed, awake. In the disease called delirium tremens, wakefulness is a constant symptom, and frequently continues for many successive days and nights. It is also an attendant upon all disorders accompanied by acute suffering, especially when the brain is affected, as in phrenitis, or fever. Maniacs, from the excited state of their sensorium, are remarkably subject to want of sleep; and this symptom is often so obstinate as to resist the most powerful remedies we can venture to prescribe.

Certain stimulating agents, such as tea or coffee,

taken shortly before going to bed, have often the effect of preventing sleep. I would impute this to their irritative properties, which, by supplying the brain with fresh sensorial power, enable it to carry on uninterruptedly all its functions longer than it would otherwise do, and consequently prevent it from relapsing into slumber at the usual period.

Any uneasy bodily feeling has the same effectboth preventing the accession of sleep, and arousing us from it when it has fairly taken place. Thus, while moderate fatigue provokes slumber, excessive fatigue, owing to the pain and irritation it necessarily occasions, drives it away. Sickness, cold, heat, pregnancy, the ordinary calls of nature, a disagreeable bed, the want of an accustomed supper, too heavy a supper, or uneasiness of any kind, have the same result. Cold is most apt to induce sleeplessness, when partial, especially if it be confined to the feet; for when general and sufficiently intense, it has the opposite effect, and gives rise to drowsiness. Certain diseases, such as hemicrania, tic doloureux, &c., have actually kept the person awake for three successive months; and all painful affections prevent sleep more or less. But the most violent tortures cannot altogether banish, however much they may retard it. Sooner or later the fatigue, which a want of it occasions, prevails, and slumber ultimately ensues.

Sleeplessness is sometimes produced by a sense of burning heat in the soles of the feet and palms of the hands, to which certain individuals are sub

ject some time after lying down. This seems to proceed from a want of perspiration in these parts; owing generally to impaired digestion.

Mental emotions, of every description, are unfavorable to repose. If a man, as soon as he lays his head upon the pillow, can banish thinking, he is morally certain to fall asleep. There are many individuals so constituted, that they can do this without effort, and the consequence is, they are excellent sleepers. It is very different with those whose minds are oppressed by care, or over-stimulated by excessive study. The sorrowful man, above all others, has the most need of sleep; but, far from shedding its benignant influence over him, it flies away, and leaves him to the communionship of his own sad thoughts:

"His slumbers-if he slumber-are not sleep,

But a continuance of enduring thought."

It is the same with the man of vivid imagination. His fancy, instead of being subdued by the spell of sleep, becomes more active than ever. Thoughts in a thousand fantastic forms—myriads of waking dreams-pass through his mind, whose excessive activity spurns at repose, and mocks all his endeavors to reduce it to quiescence. Great joy will often scare away sleep for many nights; but, in this respect, it is far inferior to grief, a fixed attack of which has been known to keep the sufferer awake for several months. Those who meditate much, seldom sleep well in the early part

of the night: they lie awake, for perhaps two or three hours, after going to bed, and do not fall into slumber till towards morning. Persons of this description often lie long, and are reputed lazy by early risers, although, it is probable, they actually sleep less than these early risers themselves. Long continued study is highly prejudicial to repose. Boerhaave mentions that, on one occasion, owing to this circumstance, he did not close his eyes for six weeks.

Nothing is so hurtful both to the mind and body as want of sleep. Deprived of the necessary portion, the person gets wan, emaciated and listless, and very soon falls into bad health; the spirit becomes entirely broken, and the fire of even the most ardent dispositions is quenched. Nor is this law peculiar to the human race, for it operates with similar power upon the lower animals, and deprives them of much of their natural ferocity. An illustration of this fact is afforded in the taming of wild elephants. These animals, when first caught, are studiously prevented from sleeping; in consequence of which, they become, in a few days, comparatively mild and harmless. Restlessness, when long protracted, may terminate in delirium, or confirmed insanity; and, in many diseases, it is the most obstinate symptom we have to struggle against. By it alone, all the existing bad symptoms are aggravated; and as soon as we can succeed in overcoming it, every thing disagreeable and dangerous frequently wears away, and the person is restored to health.

« ZurückWeiter »