nerves.

Under this immediate head I shall only add, that though the sound condition of the whole nervous system is essential to the full health and efficiency of every portion of the body; it is the derangement of the nerves of imperceptible involuntary or organic motion, that produces the most serious and fatal complaints. They are the nerves, whose action is more literally indispensable to the existence of life; while the action of the other portions of the nervous system is immediately productive of little or nothing else than modifications of life or rather modifications of vital action. But before proceeding farther in this discussion, a few remarks of a more general and abstract character are requisite.

There are three great sets or groupes of organs which constitute the basis of the being and character of man-which form I mean the most substantial and fundamental part of him, and contribute most essentially to make him what he is. These are the contents of the three great cavities of the body, and their appendages-the cranium, the thorax, and the abdomen. In plainer terms, they are the brain, spinal marrow and nerves, the lungs, heart and blood-vessels, and the chylemaking viscera consisting of the stomach and intestines, the liver, pancreas, and lacteal apparatus.

These three groups of organs are intimately connnected with and dependent on each other, in a twofold way; through sympathy or consent of parts; and through function. On the former ground, the condition of either group, whether morbid or healthy, produces a like condition in one or both of the others; and, on the latter, a derangement or failure of function in one, occasions in the others a corresponding derangement. This connexion and dependence are only stated as facts, no effort being made or intended at present to adduce their causes.

Although these sets of organs are each equally essential to human existence, and equally dependent on one another for soundness and efficiency, they hold different ranks, as respects their functions. The abdominal organs, being fitted only for digestion and chylification, are of the lowest order, and belong in some shape to the lowliest beings of the animal and vegetable kingdoms. The organs of the thorax, being framed for the maturation and circulation of the blood, are of a higher rank, and belong to a higher description of animals. But the cerebral, spinal, and nervous organs, ranking in an order still superior, belong to beings of superior classes, and, in their highest perfection, bestow on man his noblest attributes, and place him at the head of the animal creation. It is plain therefore that the improvement of the nervous system, to the utmost pitch of which it is susceptible, should constitute the leading object of all sorts of education and training. And on the attainment of that object depend the future standing, achievements, and happiness of our race, and the peace, prosperity, and glory of the world.

Is any one inclined to regard this statement as exaggerated at least, if not actually erroneous; and to ask me, whether it is not from the cultivation and improvement of the mind that results so beneficial and resplendent are to issue? Were this question put to me, my reply to it would be affirmative; but I would add, that the improvement of the nervous system, especially of the brain, and the improvement of the mind,

are the same.

We have no ground to believe, much less are we authorized to assert, that the mind, as an independent and insulated being, is improved, or, in the slightest degree altered by education and training. Indeed the alteration, either for better or worse, of a spiritual substance, by any kind of action or influ

ence on it that can be practised by us, is an event of which no conception can be formed. The thought is too subtle and etherial for imagination to grasp. Far less do we know what means to employ for the production of the effect. Nor is such an effect necessary for the attainment of the object aimed at in mental education. The improvement of the brain, the organ or instrument with which the mind works in all its operations, is sufficient for the accomplishment of the end held in view. And that that can be effected, by the suitable employment of suitable means, is an issue as certain, as that any other portion of the body can be improved.

The brain is but a mass of living organized matter, and like muscles, membranes, and all other similar masses, can be ameliorated with ease in temperament and tone, activity and power. And when thus advanced in the excellence of its qualities as a mental instrument, it follows of necessity that the mind must employ it with superior effect. This is as much of an absolute truism, in its bearing on the relation between cause and effect, as that a harp of higher finish and tone, when swept with the same skill and power, discourses more "exquisite music," than an instrument of an inferior order when out of tune.

As respects the process best fitted to improve the brain in activity and power, it is too plain to be mistaken, and too perfectly in accordance with reason and experience, to be made a subject of doubt, much less of controversy. It consists in giving to the organ a due amount of suitable exercise, and supplying it sufficiently with wholesome and well arterialized blood. And to do this is not only practicable, but exceedingly easy. That the end, however, may be fully and certainly attained, it is necessary that the brain be properly exercised in all its organs-its affective as well as its intellectual.

Partial exercise, so far as it is partial, must be comparatively fruitless. On this topic I shall only farther observe, that it is not, in mathematics, a more incontestible truth, that parallel lines can never meet, than it is in physiology, that exercise, proalike in kind, quantity, and time of employment, increases the strength and activity of living organized matter of every description.

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The questions then that first present themselves are, what is meant by the exercise of the brain? and in what way may such exercise be given to it? Nor is there any difficulty in answering them. The exercise of the brain is the heightened organic action of it; and that is produced by every form of salutary excitement. To exercise the mind is to exercise the brain, whatever may be the kind of mental operation. Is the mind actively engaged in vision, hearing, perception, observation, remembering, imagining, reasoning, thought, calculation, or in any sort of moral or religious feeling? The brain is simultaneously exercised in the organs corresponding to the kind of mental action pursued. Does the mental action consist in the indulgence of any of the of the passions or emotions?-in love or friendship, resentment or desire of revenge, in ambition, covetiveness, hope, wonder, or the contemplation and enjoyment of the sublime or the beautiful? In each and all of such cases does the brain conform in exercise to that of the mind. And its organs thus excited to action are invigorated and improved in aptitude for the performance of their functions.

That the brain may be the more certainly and competently strengthened and improved, I have said that it must be liberally supplied with arterial blood. And this end is more or less accomplished by the excitement it undergoes. "Ubi irritatio, ibi affluxus "-in whatever part of the body irrita

tion or local excitement occurs, to that spot takes place a conflux of blood. And this is a maxim of as unquestionable truth, as is that which asserts, that things equal to one and the same thing, are equal to one other. Hence in cases of deep passion, such as anger and joy, (which are nothing but high cerebral excitement and action) the countenance is flushed and full, the eyes become fierce or sparkling and prominent, and at times the head turns painful and giddy, in consequence of the rush of blood to the parts. And in these instances the energy and power of action imparted to the brain, are strikingly manifested, by the unwonted force and rapidity of conception and thought, and the augmented fluency and eloquence of utterance, which mark the occasion.

Not only moreover does the blood flow to the brain in a larger volume; it is also more highly arterialized, than usual. Of this the reason is sufficiently obvious. The high and powerful action of the brain produces through sympathy a like condition in the lungs and heart; which latter organ, by its strengthened and accelerated pulsations, pours into the former an augmented stream of blood. Here again there is an increase of action. Respiration becoming more frequent and full, a larger amount of air is received into the lungs. The blood is hence more highly arterialized, and, passing in this condition to the left side of the heart, is thrown in greater force and quantity into the brain, the more thoroughly to vitalize, excite, and invigorate that viscus. Thus do the viscera of those two cavities, the skull and the thorax, operate on each other in a circle, or in a flux and reflux of influence, to the mutual increase of their power and action. Nor is this all.

The viscera of the third great cavity, the abdomen, which prepare the chyle, participate extensively in the general work.