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illustrated in every voluntary movement of the body. I will to raise the left foot instead of the right, or the arm instead of the foot, and instant action of the member takes place in obedience to the mandate. An obstruction is to be cleared from my path. I elect which shall do it, the hand or the foot, and the member receiving the command executes the commission. Some functions, it is true, can be executed only by the hand; others only by the foot; still others only by the teeth, and so on; but above we have reference to cases where the instruments are interchangeable.
Something akin to this is observed in sensation. In many cases the mind may select from among the organs of sense which it will employ to test the external objects. Some things, like the colors, can be tested only by sight; others, like sound, only by the ear, and so on. But there are objects, like a piece of butcher's meat, or a fish, or a quantity of sugar, or a hogshead of tobacco, in the testing of which more than one of the senses may be employed. In such a case the mind elects which sense, whether the sight, the taste, the touch, or the smell; and, indeed, it may employ the whole of them. Here is a distinct election, made by the soul, among the senses, showing them to be merely the instruments used by the mind for the accomplishment of its purposes. In all this the mind handles the organ of sense just as the optician handles his optical instrument, or as the experimenter in acoustics handles his acoustic tubes.
II. That the organs of sense mere instruments is further proved from the fact that attention to the impression made ироп
necessary to sensation. Sensation is something more than an impression made upon the bodily organ; it implies also a change in the state of that which is conscious in the body—the soul. Without
this there is really no sensation. “We are accustomed to say the eye sees, the ear hears, the finger feels, and so forth; but such language is used only in accommodation to our ignorance, or from the force of habit. It is incorrect. The eye itself no more sees than the telescope which we hold before it to assist our vision; the ear hears not any more than the trumpet of tin which the deaf man directs toward the speaker to convey the sound of his voice; and so with regard to all the organs of sense. They are but instruments which become the media of intelligence to the absolute mind, which uses them whenever it is inclined or obliged to do so.''*
The eye is a most perfect optical instrument, combining, by a most exquisite apparatus, those distinct qualities of the camera-obscura and the telescope.
The ear is a most perfect acoustic instrument. Human skill has never been able to equal the divine model. So each organ of sense is an instrument, special in its structure and in its purpose—the whole together bearing glorious attestation to the wonderful skill and wisdom of the Creator.
The working of this machinery is so complete, noiseless, and yet with such inconceivable velocity, that we hardly wonder it seems self-moved. The organs of sense and of action are so instantaneously respondent to the slightest intimation of the will that the very consciousness of willing is almost lost sight of.
And yet the simple fact is apparent that the soul may become so profoundly absorbed in some mighty thought, or in the solution of some intellectual problem, that, though the chords of every sense should be swept by the corresponding elements in nature from without, no sensation would occur within. The mind is dead to any impression upon the organ. What higher demonstration can be
*Soul and Body, by Dr. Moore, p. 25.
demanded, that the bodily senses are mere organic instruments of the soul?
III. The mind not only interprets the impression made upon
the organs of sense, but has the power of comparing sen. sations and thus perfecting its knowledge of external things.
The nerves are the media of communication between the organs of sense and the brain. The impressions made upon the former by an external object, they take up
convey to the latter. Here, so far as science has explored, the physical process ends. The instrument has performed its appointed function. How the mind takes up the process so as to carry the impression forward into the intelligence, is an unsolved mystery. Human reason may never, in this state, be able to solve it. But this fact we do know, that where the physical process ceases, the intellectual begins. The connection is complete. Though the links that bind it are unseen, the physical and the intellectual stand before us in manifest union.
Now, it is evident that these four things are necessary in order to sensation, namely—the presence of an external object having a position and nature adapted to affect the sense, an impression upon the organ, the conveyance of that impression to the brain by the nerves, and the apprehension of that impression by the soul.
This process may be interrupted in any of its successive stages, and thus fail to produce the sensation. First, through some obstruction or defect, the sensorial organ may fail to receive its appropriate impression. If the retina of the eye, for instance, is inflamed, the picture, as in a poor looking-glass, will be defective. This defective impression will be conveyed to the brain, and the corresponding sensation will also partake of the defect. Again, if the optic nerve is diseased, it will, like a defective telegraph wire, fail to transmit its message.
In the electrical tele.
graph, the battery may be good, the appropriate shock may be made, and the careful observer at the other end may watch and wait; but all in vain. The message is lost on the way. It is diverted because the wire is not properly insulated; or it is obstructed in consequence of the wire being broken or an imperfect conductor. In like manner in the use of the senses. Unless the nerve is in a healthy condition it fails to transmit the impression to the brain. Though the impression, clear and distinct, is made upon the receiving organ of sense, and though the soul watches and waits at the other end of this wonderful magnetic line, yet no message comes to it.
Then, finally, the organ of sense may receive its appropriate impression, the connecting nerve may take it up and carry it to the brain. But unless the mind gives attention to it there, no sensation results. This is evident from the instances every day occurring, in which, though the senses are known to be unimpaired, the nervous system soundall its functions complete—and also all the external causes of sensation existing; and yet no sensation occurs, for the reason that the mind is abstracted in some deep and absorbing reverie, or by some difficult and perplexing question.
As a familiar example, an individual absorbed in some difficult mathematical problem or in an interesting book, may be spoken to two or three times before his attention is arrested. The vibrations of air struck upon the tympanum as usual, and the acoustic nerve bore the impression to the brain; but the operator there was inattentive, and the mes
sage was lost.
The relation of the senses to the mind as instruments for the conveyance of impressions, and the relation of the mind to the senses as the interpreter of those impressions, becomes still further apparent when we observe the mind
comparing the impressions received from the different senses, in order to the perfecting of the knowledge acquired through those sensations.
A vase stands upon the mantle, containing what appears to be an exquisite bouquet of flowers. That is the intimation of the sense of sight. But I approach, subject them to the test of the sense of smell, and find they have no flavor. I try the sense of touch upon them, and find they are stiff and the surface hard and cold. The mind sits in judgment upon these three classes of sensation, and thus ascertains that this is not a bouquet of real flowers, but a delicate representation of them. Along side of this is what appears to the eye a basket of fruit. Such is the sensation produced by sight. But when I subject it to the touch, it is cold and hard; when I take it into the mouth, it is without taste. Then I discover it is not fruit, but a wax representation, yet so delicate as to deceive the eye.
It will be perceived that, in both these cases, the mind made a comparison between the sensations produced by the different senses, and that its knowledge of the external object was the result of that comparison. Without this internal interpreter of our sensations—this arbiter among them--the senses would be constantly leading us astray. We should be their perpetual dupes. But wisely has the . Creator of all ordained the function of this central life of our being. "Try the spirits," is an aphorism of Revelation; "try the sensations,” is a correspondent aphorism of science.
This idea of the mind's arbitration among the sensations produced within is more difficult of comprehension, from a common error in regard to the process of perception. Perception constantly carries us without ourselves, and we constantly recognize the objects as being without. And thus we form an idea of the mind—not as inclosed within its