CHAPTER II. MINE AS AFFECTED BY CERTAIN STATES OF THE BRAIN AND NERVOUS SYSTEM. Statement. There are certain mental phenomena connected with the relation which the mind sustains to the nervous organism, and depending intimately on the state of that organism, which seem to require the notice of the psy. chologist, though often overlooked by him; I refer to the phenomena of sleep, dreams, somnambulism, and insanity. So far as the activity of the mind is involved in these states or phenomena, they become proper objects of psychological inquiry. They present many problems difficult of solution, yet not the less curious and interesting, as phases of mental activity hitherto little understood. View sometimes taken by Physiologists. It becomes the more important for the psychologist to investigate these phenomena, inasmuch as views and theories little accordant with the true philosophy of the mind have sometimes been put forth by physiologists, in attempting to explain the phenomena in question. They have viewed the cerebral apparatus as competent of itself to produce the phenomena of thought, as self-acting, in the absence of the higher principle of intelligence which usually governs its operations, carrying on by a sort of automatic action, the processes usually ascribed to the mind or spiritual principle, while consciousness and volition are entirely suspended. Consciousness, in fact, is nothing but sensation, and thought a mere function of the brain. This is downright materialism, a doctrine utterly subversive of the very existence of that which we call mind or soul in man. If the cerebral organization is competent of itself during sleep to carry ou those operations which in waking moments are ascribed to the spiritual ele ment of our being, if thought is a function of the brain, as digestion is of the stomach, what need and what evidence of any thing more than merely cerebral action at any time? What, in fact, is the mind itself but cerebral activity, and what is man, with all his higher powers, but a mere arimated organism? It becomes important, then, to account for the phenomena under consideration in some way more consistent with all just and true notions of the nature and philosophy of mind. Distinction of normal and abnormal States. — Of these phenomena, while all may be regarded as intimately connected with and dependent on the state of the brain and nervous system, some seem to proceed from a normal, others from an abnormal and disordered state of the nervous and particularly the cerebral organism. Of the former class, are sleep and dreams; of the latter, somnambulism, the mesmeric state, so called, and the various forms of disordered mental action, or insanity. § L-SLEEP. » Meaning of the Term. What is sleep? Will the name itself afford any solution of this problem? Like most names of familiar things, we find the word descriptive of some particular circumstance or phase, some one prominent sharacteristic of the thing in question, rather than a defi nition-much less an explanation of the thing itself. The word sleep, from schlafen, as the Latin somnus from supinus, refers to the supine condition and appearance of the body when in this state; the relaxing of the muscles, the falling back or sinking down of the frame, if unsup ported. This is the first and most obvious effect to the eye of an observer, of the condition of sleep as regards the body. Further than this the word gives us no light. 1. Sleep involves primarily Loss of Consciousness.- What then, further than this, is sleep? If we observe somewhat closely, and with a view to scientific arrangement, the different aspects or phenomena that present themselves as constituting that state of body and mind which we call sleep, the primary and most obvious fact, I apprehend, is loss of con sciousness, of the me. Not perhaps of all consciousness, for we seem still to exist, but of self-consciousness, of the me as related to time, and place, and external circumstance. We lose ourselves, as a common but most exact expression describes it. We are not at the Time aware of this Loss. — Of course, sleep consisting primarily in loss of consciousness, we are not conscious of the fact that we sleep, for this would be a consciousness that we were unconscious. Illustrations of this fact are of frequent occurrence. You are of an evening getting weary over your book. You are vaguely conscious of that weariness, amounting even to drowsiness; you find it difficult to follow the course of thought, or even to keep the line, but have no idea that you are at length actually asleep for the moment, till the sudden fall of the book awak. ens you. Nay, one who has been vigorously nodding for five minutes will, on recovering himself, stoutly deny that he has really been asleep at all; the truth is, he was not conscious of it; we never are, directly. This results from what? — This loss of consciousness results from the inactivity of the bodily senses. It is these that afford us the data for a knowledge of self in relation to external things. In sleep these avenues of communication with the external world are shut up, and we silently drop off, and, as it were, float away from all conscious connection with it. We no longer recognize our relations to time and space, nor even to our own bodies, which, as material, come under those relations; for it is by the senses alone that we get these ideas. So far as consciousness of these relations is concerned, we exist in sleep as in death. out of the laws and limits of time and space, and irrespective of the body and of all material existence. Mental action, however, doubtless goes on, and we are conscious of thought and of the feeling of the moment, but of nothing further. All self-consciousness is gone. An Affection primarily of the nervous System. - Sleep, then, would seem to be primarily an affection of the nervous system; not of the reproductive-that goes on as usual, and even with increased vigor; nor yet of the muscular — that is still capable of action; but only of the nervous. That gets weary; by continued use, its vital active force is exhausted, it needs rest, becomes inactive, gradually drops off, and so there results this loss of consciousness, of which I have spoken. It is strictly, then, the nervous system, and not the whole body that sleeps. Touch, and hearing, Hence, noises so easily Hence, too, we are most Different Senses fall Asleep successively. The different senses become inactive and fall asleep, not all at once, but successively. First, sight goes. The eye-lids droop, and close. Taste and smell probably next. are among the last to give way. disturb us, when falling asleep. easily awaked by some one repeating our name, or by some one touching us. These senses are also the first to waken. One sense may be asleep and another awake. You may still hear what one is saying that sits near you, when already the eye is asleep. So in death, one hears when no longer able to see or to speak. 2. Loss of personal Control.- Accompanying this loss of self-consciousness is the loss of personal control, i. e., the control of the will over the bodily organization. This follows from the inactivity of the senses and of the nervous system, for it is only through that, and not by direct agency of the will, that we, at any time, exert voluntary power over the body. When that system becomes exhausted, and its force is spent, so that it can no longer furnish the motive power, nor execute the commands of the higher intelligence the will no longer maintains its empire over the physical organization, its little realm of matter, its control is sus pended, its sceptre falls, and it realizes for the time the story of the enchanted palace on which a magic spell had fallen, suddenly arresting the busy tide of life, and sealing up, on the instant, the senses of king, courtiers, and attendants, in the unbroken sleep of ages. Indications of approaching Sleep. One of the first indications, accordingly, of the approach of sleep, is the relaxing of the muscles, the drooping of the eye-lid, the dropping of the head and of the arm, the sinking down of the body from an erect to a supine position. If in church, the head seeks the friendly support of the pew in front, fortunate if it can secure itself there from the still further demands of gravitation. Analogous Cases. In respect to the point now under consideration, the loss of control over the physical frame, the phenomena of sleep closely resemble those of intoxication, and of fainting; and for the same reason, in either case, i. e., the inactivity of the nervous system, which is the medium of voluntary power over the body. That inactivity of the nervous system is produced in the one case by natural, in the other by unnatural causes, but the direct effect is the same as regards the loss of voluntary power. The same effects are also produced in certain diseases, and eventually by death. 3. Loss of Control over the Mind. - Analogous to this is the loss of voluntary control over the mental operations, which is in fact, so far as the mind is concerned, the essential feature and characteristic of sleep. Mental action still goes on, there is reason to suppose; in many cases we know. that it does; but the thoughts come and go at their own pleasure, without regulation or control. It is not in our power to arrest a certain thought, and fix our minds upon it for the time, to the exclusion of others, as we can do in the waking moments, and which constitutes, in fact, the chief |