will allow to other countries the most splendid efforts of genius directed to this object; but they have passed away, and are now no more than beautiful and stupendous errors. We will give up to them the mastery in all that class of men who can diffuse over bad and unsocial principles, the charms of eloquence and wit; but the great teachers of mankind, big with better hopes than their own days could supply,-who have looked backward to the errors, and forward to the progress of mankind,-who have searched for knowledge only from experience, and applied it only to the promotion of human happiness, who have disdained paradox and impiety, and coveted no other fame than that which was founded upon the modest investigation of truth,—such men have sprung from this country, and have shed upon it the everlasting luster of their names. Descartes has perished, Leibnitz is fading away; but Bacon, and Locke, and Newton remain, as the Danube and the Alps remain :-the learned examine them, and the ignorant, who forget lesser streams and humbler hills, remember them as the glories and prominences of the world. And let us never, in thinking of perpetuity and duration, confine that notion to the physical works of nature, and forget the eternity of fame! God has shown his power in the stars and the firmament, in the aged hills and in the perpetual streams; but he has shown it as much, in the minds of the greatest of human beings! Homer and Virgil and Milton, and Locke and Bacon and Newton, are as great as the hills and the streams; and will endure till heaven and earth shall pass away, and the whole fabric of nature is shaken into dissolution and eternal ashes.

LECTURE IV.

ON THE POWERS OF EXTERNAL PERCEPTION.

[IMPERFECT.]

I PROMISED, in the beginning of these lectures, to be very dull and unamusing; and I am of opinion that I have hitherto acted up to the spirit of my contract; but if there should perchance exist in any man's mind the slightest suspicion of my good faith, I think this day's lecture will entirely remove that suspicion, and that I shall turn out to be a man of unsullied veracity!

A list of great and splendid names, such as I gave in my last lecture, of itself was some obstacle to the completion of my promise. I have no doubt, however, but that I overcame that obstacle with sufficient success; and, of course, that aided as I am by the subject to-day, it will be still more perfect, and my fortune more complete. It is some encouragement to me, however, in the execution of my plan, to perceive the extreme patience with which subjects are listened to, upon other occasions, which in their nature are not capable of eloquence, and in which all ornament would be impertinent and misplaced. I think I have observed, that the ornaments called for here are established facts and fair reasonings; and that the object for which both sexes pass an hour in this place is, to hear the investigation of some important subject, made with some care, and conducted without any pretense. Without offering, therefore, any other apology in future, for the dryness and barrenness of the subject, but trusting to the candor and good sense of those who hear me, I shall at once proceed upon my subject.

Every one knows that the senses are five number, Smell, Taste, Hearing, Feeling, and Seeing. The nostril, the eye, and the ear, are affected by objects at a distance through the instrumentality of light, air, or the thin element which emanates from odorous bodies. The senses of taste and feeling are commonly, if not always, affected by actual contact with the bodies themselves.

In the dissection of the human body, there are found thin, white, minute filaments penetrating every part of it in every direction. Every one of these, let its ramifications be ever so extensive, can at last be distinctly traced either to the brain, or to the spinal marrow, which proceeds immediately from the brain, and is of course connected with it. The use of these nerves is, to convey notions or ideas from exterior objects to the brain; and if this communication between the various parts of the body and the brain be intercepted by any injury done to the nerve which keeps up the communication, no intelligence can reach the understanding from that part of the body. For instance, at present I feel perfectly well with my hand; but if the great nerve that runs down my arm were divided, I should have no sort of feeling in that part of my arm below which the separation took place. I might pierce my hand with a knife, or burn it with fire, without having the smallest sense of pain, or being in the least degree conscious that my hand was even touched. In the same manner, if the spinal marrow be injured, all the parts of the body whose nerves fall into that great channel of intelligence below the part injured become absolutely devoid of all feeling; and though in this case the lower extremities do not mortify, they are dead branches, without the privilege of sensibility, or the enjoyment of any of the functions of their healthy. condition; and as the extremities can not convey, in the case of an injured nerve, any intelligence to the understanding, it can not exercise any sort of power over the diseased limb. For when my arm (to put the case I before cited) is injured, and can not feel, it can not obey the will; for, however I may wish to move it, its motion is utterly impossible. Therefore a nerve not only conveys the knowledge of outward objects to the

mind, but it conveys the decisions of the will to the various parts of the body. In short, to use a very trite and obvious simile, the brain is the metropolis, the nerves are paths and roads to it from every part of the animal frame, the greatest of which is the spinal marrow, absorbing a vast number of lesser communications before it is terminated in the grand emporium of thought. To carry on this threadbare simile a little further, we may say, that the information thus brought to the brain, is rapid and telegraphic beyond all conception; the obedience rendered to its commands, dispersed over the body, instant and profound; and the effects of a very short interruption of correspondence so fatal, that the importance of the region thus separated is forever destroyed.

Now, then, this is a short history of the connection between mind and body. We know that the notion must enter by one of the senses, we know it must be conveyed by a nerve to the brain, and there our knowledge ends! All beyond this is mere fiction and hypothesis. Whether there be a fluid passing through the nerve, as was long supposed,-whether the nerve excite vibrations and vibratiuncles in the brain, as Newton queried, and Hartley thought,-whether the pineal gland be the seat of the soul, according to Descartes; or whether it lodge in the oval center of the brain, according to Vieussens; or whether, as Willis contends, common sense is lodged in the corpora striata, and imagination in the corpus callosum, all these are the opinions of rash or ingenious men, without any foundation. What additions may hereafter be made to these discoveries it is impossible to say, but at present our knowledge is stopped exactly where I have stated. We know the entrance, the path, and the place of destination; the mode of proceeding, and the effects after it has reached its goal, we do not know.

There are two common errors respecting our sensations which those who have been in any degree accustomed to these sorts of speculations will hardly remember, and those who have not, will find, perhaps, some trifling difficulty in correcting, I mean, the reference of our sensations to the objects which cause them, and

to the senses which convey them. I say that I feel with my hand, and that I see with my eye; but what are seeing and feeling? They are affections of the mind, not of the body. My eye conveys to me the notion that this paper is white, and my hand is an instrument to inform me this table is hard; but the notions themselves exist only in my mind, and can not exist in my eye or my hand, which are mere brute matter, and quite incapable of intelligence. There are many things which we can only see through a microscope, but it would be very absurd to suppose that the microscope sees;-put away the microscope, and it is just as absurd to suppose the eye sees. The eye is a mere machine, like the other, to convey knowledge to the mind; the only difference is, when we use a microscope we use two optical machines, when we use the eye alone we employ only one. If we suppose the thought itself to exist in the mere instrument of thinking, we must, in the case of feeling, suppose mind to be spread over all the body. There is a mind in each foot and in every finger, and we kneel upon mind and sit down upon it; and the old proverb, "many men, many minds," may with equal propriety be asserted of a single individual. The second popular mistake which I specified is, that of attributing our own sensations to the bodies which occasion them. If I speak of the smell of a rose, I mean that that flower affects my mind through the organs of smelling in that particular manner;-the smell is not in the rose, it is in my mind; there is an unknown cause in the rose which excites this feeling of the mind called smell. There is an organ through which that effect is produced; but the effect itself is in my mind. Just so, the color is not in the table, for the word color means nothing more than an affection of my mind; but there is an unknown cause in this wood which produces that effect upon my mind through the medium of my eye. And, in general, we must always carry it in our recollection, that in speaking of sensation, we are speaking of what exists in our minds; and that when we refer these to the objects by which, or the instruments through which, they are