Mental Phenomena.

MIND AND BODY.

Ir has been observed that the mental powers, unlike the bodily, do not suffer from the effects of time, but continue, as life advances, to enlarge and exalt themselves. Lord Brougham says:

It is an undoubted fact, and almost universally true, that the Mind, before extreme old age, becomes more sound, and is capable of greater things, during nearly thirty years of diminished bodily powers; that in most cases, it suffers no abatement of strength during ten years more of bodily decline; that in many cases, a few years more of bodily decrepitude produce no effect upon the mind; and that in some Jistances its faculties remain bright to the last, surviving almost totally the total extinction of the corporeal endowments. It is certain that the strength of the Body, its agility, its patience of fatigue, indeed, all its qualities, decline from thirty at the latest; and yet the mind is improving rapidly from thirty to fifty; suffers little or no decline before sixty; and therefore, is better, when the body is enfeebled, at the age of fifty-eight or fifty-nine, than it was in the acme of the corporeal faculties thirty years before. It is equally certain that, while the body is rapidly decaying, between sixty or sixty-three and seventy, the mind suffers hardly any loss of strength in the generality of men; that men continue to seventy-five or seventy-six in the possession of all their mental powers, while few can then boast of more than the remains of physical strength; and instances are not wanting of persons, who, between eighty or ninety, or even older, when the body can hardly be said to live, possess every faculty of the mind unimpaired.

We are authorised to conclude from these facts, that unless some unusual and violent accident interferes, such as a serious illness or a violent contusion, the ordinary course of life presents the mind and the body running courses widely different, and in great part of the time in opposite directions: and this affords strong proof, both that the mind is independent of the body, and that its destruction in the period of its entire vigour is contrary to the analogy of nature.--Discourse of Natural Theology, pp. 119–121.

Dr. Cromwell gives as the leading doctrine of his work, that Mind is no independent immaterial essence, but the most excellent and exalted among the numerous and varied phenomena of life. "Though," says Mr. Spencer, "we commonly regard mental and bodily life as distinct, it needs only to ascend somewhat above the ordinary point of view, to see that they are but subdivisions of life in general; and that a line of demarcation can be drawn between them otherwise than arbitrarily." (Elements of Psychology,

Mental Processes of which we are Unconscious. 65

p. 349.) And if the oft-put question again follow, "What is life?" we repeat that it cannot be more closely defined than as the expression by operation of the laws of the states, functions, and actions, by which an organism manifests itself to be alive."

MENTAL PROCESSES OF WHICH WE ARE UNCONSCIOUS.

It has long been our practice, in order to master a subject of difficulty, to assemble the facts and reasonings, to weigh and consider them thoroughly, and having done so, to take leave of the matter until the next day, or for a short interval; when, on returning to it, we have, invariably, been the better able to master the inquiry. This result may, perhaps, be attributed to returning to the subject with a fresh eye and recruited brain; but this is not precisely the explanation. In Sir Benjamin Brodie's Psychological Inquiries, we find it stated that a remarkable process takes place in the mind, which is independent of any direct act of volition; as if there were in the mind a principle of order which operates without our being at the time conscious of it." The explanation is thus given in the First Dialogue:

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Crites. It has often happened to me to have been occupied by a particular subject of inquiry; to have accumulated a store of facts connected with it; but to have been able to proceed no further. Then, after an interval of time, without any addition to my stock of knowledge, I have found the obscurity and confusion in which the subject was originally enveloped, to have cleared away; the facts have seemed all to have settled themselves in their right places, and their mutual relations to have become apparent, although I have not been sensible of having made any distinct effort for that purpose.

Eubulus. What you have now described has occurred repeatedly to myself. It is certainly not very easy to comprehend the nature of this mental operation. Is it that the subject every now and then comes before us, and is considered without our recollecting it afterwards?-or is it, as a philosophical friend as suggested, that in the first instance we are perplexed by the multiplicity of facts presented to us, and that after an interval of time, those of less importance fade away, while the memory retains those which are essential, in the subsequent arrangement or classification of which, being thus rendered more conspicuous, there is no difficulty?

Crites. The latter seems to be the more probable explanation of the two. At the same time, it must be admitted that they are not incompatible with each other.

Accordingly, as men possess this faculty of keeping the attention fixed on a particular object until we have, as it were, looked all around it, will be the success of taking cognizance of relations of which another mind has no perception. It is this, much more than any difference in the abstract power of reasoning, which constitutes the vast difference which exists between the minds of different individuals. "I keep the subject," said Sir Isaac

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Newton, "constantly before me, and wait until the first dawnings open by little and little into a full light." It was thus that, after long meditation, he was led to the invention of fluxions, and to the anticipation of the modern discovery of the combustibility of the diamond.

THE VOLTAIC BATTERY, THE ELECTRIC EEL, AND THE BRAIN OF MAN.

We boast of our Voltaic Battery; but when we compare it with the battery which Nature has given to the electrical eel and torpedo, how insignificant are human operations compared with those of the Architect of living beings! The stupendous electrical eel exhibited some years since at the Polytechnic Institution, when he sought to kill his prey, inclosed him in a circle; then by volition caused the voltaic force to be produced, and the hapless creature was instantly killed. It would probably require ten thousand artificial batteries to effect the same object, as the creature was killed instanter on receiving the shock. As much, however, as Smee's battery is inferior to that of the electric fish, so is man superior to the same animal. Man is endowed with a power of mind competent to appreciate the force of matter, and is thus enabled to make the battery. The eel can but use the specific apparatus which nature has bestowed upon it.

If the brain, (says Sir John Herschel,) be an electric pile constantly in action, it may be conceived to discharge itself at regular intervals, when the tension of the electricity reaches a certain point, along the nerves which communicate with the heart, and thus excite the pulsation of that organ.

A GALVANISED HUMAN BODY.

The appearances produced by the agency of galvanism on the human body are of the most frightful nature, and awaken horrible fancies in the mind of the spectator: the eyes roll wildly, and the countenance is distorted with ghastly grins, whilst the limbs move in forcible and convulsive actions. The most successful effort to resuscitate by galvanism was that made on the body of John White, who was executed for a murder at Louisville. The body, after hanging twenty-five minutes, was cut down, and whilst yet warm, and even trembling, was subjected to the stimulus of galvanism. The man suddenly rose from the bench to a sitting posture, afterwards stood on his feet, opened his eyes, and gave a terrific screech. His chest worked as if in respiration. One of the surgeons present exclaimed that he was alive. On another shock being given, he jumped up with a sudden bound, disengaged himself from the wires, and ran into a corner of the room.

He

Changes in the Nervous System.

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He

frequently opened his eyes, and the breathing became so regular, that many addressed him, but he made no sign of understanding. Nevertheless, by the assistance of a medical student, he took a few steps on the floor, and seated himself in an arm-chair. seemed like a man intoxicated, and overcome with the exertion he had made. Every effort was put in practice to equalise the circulation; but congestion of the brain eventually came on, and terminated his existence. A man named Clydesdale, who was executed for murder at Glasgow, was also made the subject of a similar experiment.—Harrison on the Medical Aspects of Death.

CHANGES IN THE NERVOUS SYSTEM.

Sir Benjamin Brodie considers it (1) very probable that the Nervous Force is some modification of the force which produces the phenomena of electricity and magnetism; and he compares the generation of it by the oxygenated blood on the grey substance of the brain and spinal chord, to the production of the electric force by the action of the acid solution on the metallic plates in the cells of a voltaic battery.

2. We know that the solid parts of the body are in a state of perpetual change. There is a constant influx of new materials supplied by the digestive organs, and in other ways; and a corresponding efflux of the old materials by means of the various excretions, especially by that of the kidneys. The brain itself forms no exception to the general rule. We cannot otherwise account for its growth in the early part of life, nor for the alterations in its structure which arise as the consequence of disease, nor for those other changes which occur in extreme old age. The mind preserves its identity, but there is no corresponding identity of the corporeal organ with which it is associated; and we may even venture to assert that the brain of to-day is not precisely and in all respects the same with the brain of yesterday, and that it will not be the brain of to-morrow.

3. We cannot suppose that such deposition of new materials and abstraction of old ones can be effected by mere mechanical means, as you would take one brick from a building and substitute another in its place. The elements of which the nervous system is composed exist in the blood, but they must undergo a new chemical combination before they can be incorporated with it; and in like manner they must undergo a chemical change of an opposite kind before they can re-enter the current of the circulation. The precise character of these chemical changes we have no means of ascertaining; but whatever it may, there is reason to believe that it must be in proportion as the nervous system is more or less exercised.

The nervous substance is distinguished from all the other tissues

(with the exception of the bones) by the very large proportion of phosphorus which enters into its composition, amounting to 1.5 parts in 100, and to as much as one-thirteenth of the solid matter which remains after the evaporation of the water; and that one result of over exercise of the nervous system is the elimination of an unusual quantity of salts containing phosphorus, by means of the secretions of the kidneys. This fact was first observed by Dr. Prout, who has given it as his opinion "that the phosphorus in organized beings is in some measure connected with the nervous tissues and nervous action."

Lastly, Sir Benjamin Brodie considers that even if we had more perfect organs of sense, or more perfect microscopes, we could trace exactly the changes which took place in the brain, we should be just as far from identifying physical and mental phenomena with each other as we are at present. The link between them would still be wanting, and it would be as idle to speculate on the nature of the relation between mind and matter, as on the proximate cause of gravitation, or of magnetic attraction and repulsion.-Selected and Abridged from Psychological Inquiries.

Dr. Forbes Winslow has thus sketched what may be termed the ubiquitous existences of the Nervous System:

From the maggot that leaps from a nut as we crack it in our plate after dinner, and the caterpillar that eats up the leaves of our favourite convolvulus in the garden-from the fish that cleaves the green, translucent wave, and the bird that wings the breeze of incense-breathing morn-from the lion that roams the desert wild, and the horse that tramps the battle field, or prances before the lady's equipage-up to Man, the master of them all, there is one all-pervading Nervous System, progressively diminishing in a downward scale of analytic exhaustion, till it ends in a mere microscopic globule of a brain, by which they all communicate and hold their relative and inter-dependent existences, according to their various forms and needs, and types of organization, function, growth, location, and pursuits.

WORKING OF THE BRAIN.

From several causes within medical experience, it would seem that Motion of the Brain is, at least, coincident with every mental operation. Thus, "in a case reported by Dr. Pierquin, observed by him in one of the hospitals of Montpellier in 1821, he saw, in a female patient, part of whose skull had been removed, the brain motionless, and lying within the cranium, when she was in a dreamless sleep; in motion, and protruding without the skull, when she was agitated by dreams; more protruded in dreams reported by herself to be vivid; and still more so, when perfectly