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system of fibres, which, as Dr. Marshall Hall has so ably taught us, is truly of a double character, carrying to the centre, within, every variety of sensation from without, and transmitting to every muscle, by a reflex action, the consequence of any stimulus so applied to the circumference; or, without such stimulus, transmitting to the muscles the dictates of the will. All muscular movements then, except those on which the processes of organic life depend—as those of the heart, the chest, the intestines, the uterus, &c.—are either the consequences of the application of some stimulus to the extremities of the afferent nerves, or are actions dictated by the mind, whose will is conveyed by the nerves to such muscles as it desires to set in action.

The brain must be regarded as the organ of the mind, just as much as the legs are the organs of locomotion, or the hands the organs of prehension. It is the medium through which that spiritual essence we call mind receives impressions, and the means by which it directs the actions of the organs of the body: thus displaying its will, and communicating with the world around. A healthy state of the brain, then, is as essential to the action of the mind, as a sound state of the leg to motion, or of the eye to vision.

The manner in which the mind is bound up with the body defies all investigation. Although it is impossible to regard the mental powers as qualities of matter, yet it is almost as difficult to contemplate them apart from that material organ which gives evidence of their existence, and the means of their activity. Sight is no part of the eye, hearing of the ear, or reason of the brain ; yet without these organs neither sight, hearing, nor reason, can be made manifest. An injury done to the retina or to the auditory nerve, destroys at once vision or hearing; yet if the mind be in a sound state, the accident cannot have affected those faculties of the mind. The mind's eye, the mind's ear, so to speak, are still perfect, the injury has merely destroyed the means by which the mind (as far as those faculties are concerned,) is linked with the external world. All the impressions received by the mind from without, are received through the organs of sensation. All external manifestations of the mind are made by the organs of speech or action. What the mind is, or how it is connected with organisation, we shall probably never know; neither is it important to our present purpose, nor indeed to the study of its action. It is clear that only through the bodily organs can it make itself manifest. It is true that sight is not in

the eye, nor hearing in the ear, nor judgment in the cerebrum; yet, independently of those organs, these faculties are absolutely useless. I believe it would much facilitate our inquiries, if we were to regard the human mind as at all times an immaterial entity, superadded to organisation, but not in any way dependent on it, nor necessarily connected with it. We may, then, regard the mind as equally perfect during the whole period of life; the same at the first as at the last day of existence; varying at various times not in its own innate powers, but in the stores of knowledge it may have acquired by communication with the world around it, and in the organised means by which it can manifest its operations.

When we speak, then, of the growth of the mind, we do not mean the growth of the actual mental powers, but the augmentation of the stores of knowledge which are gradually acquired by the mind, and which are essential to its daily action. Now these stores of knowledge are gained only through the organs of sensation, and it is therefore evident that the perfection of these organs is necessary for supplying the mind with wholesome food; to promote, not the growth of its abstract power, (which, being incorporeal, may be always equal,) but the accumulation of those clear impressions from with

out, which enable it so to exert itself as to act in that manner which we call wisely. The organs of infancy cannot convey correct impressions to the mind, nor is the brain perhaps sufficiently consolidated to receive them properly; it is necessary that a certain maturity of organization should exist, in order that the impression conveyed to the mind be clear and definite, that many various and repeated impressions should have been made before it can have gained an adequate store of knowledge, an adequate mass of materials whereon to exert its powers. Perception, memory, imagination, and judgment, are usually regarded as the four great powers of the mind. Of

' If this view be correct, there are no such things as mental diseases. The mind may vary in its original power ; but the changes which seem to occur in it, are really the results of changes in that organization through which it receives its impressions, or by which it manifests its existence. Recoveries from the various states called diseases of mind appear to me strongly to confirm this view of the subject; for it is difficult to imagine how an incorporeal essence can become the subject of disease, or can recover ; but easy to understand that if its material agents are injured its actions must be suspended or changed, and may be again restored in the same way; as, if the hand be injured by a bruise or wound, it will be unable to grasp anything, notwithstanding that the mind might will that it should do so; and the nervous fibres bear to the disabled muscles the mandates of the will, but if the bruise or wound be healed the muscles of the hand will then become again obedient to the dictates of the mind.

? It is, perhaps, only the fourth which we can truly regard as the reasoning faculty, and the source of the will.

these, perception is the great supplying power on which the others depend. The eye perceives all that passes around it; and by the use of letters it is enabled to peruse the records of past events, and thus, as it were, to see all that has ever been, and all that now is, throughout the world. Nay, more, to commune with the bygone races of mankind, and learn all that they saw, heard, read, or thought. In the same way the ear, the touch, the taste, the smell, minister to the mental storehouse, carrying valuable impressions of all around. Memory is but the power of calling up, from the well-arranged stores of knowledge, past impressions and the effects produced by them.

Imagination is but the faculty of comparing old impressions and arranging them in new forms, or under new circumstances. It is erroneous to regard imagination as a creative power. We cannot imagine anything but as resembling something we know. The ancients clothed their deities with human powers and faculties in an exaggerated degree, or they united, as is shown in the sculptures from Nineveh, the attributes and powers of various kinds of beings. Whenever we attempt to go beyond this, we deceive ourselves by mere words; thus, the terms space, eternity, are not and never can be definite ideas, but

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