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incontrovertible evidence in the very structure of the instrument that it was made to be operated upon from without. If it is to give forth melody, it must be moved by something not itself. It is composed of wood and metal and ivory, all of which, with all their complicated mechanical arrangements, are inert, and, if taken alone, are wholly valueless in the production of music.

In one portion of the organ we have a keyboard; and, in the case supposed, we look on the very intricate combinations and motions in the keys, and see no cause for the movements. But we know, if we are sane, that every change must have an adequate cause. We find a perfect correspondence between the motions of the keys and the pulsations of the melody rising and falling in this temple. But this parallelism is not identity. The keys in motion are not the music. Motions and forces are not the same.

Let, now, some inquirer of narrow mental horizon, and confusing -as so much current discussion does―motions with forces, assert that these intelligent movements of the keys-which, of course, must have behind them forces containing intelligence-are the sole cause of the anthem. Let him insist on a new definition of ivory. Let him affirm that the matter composing these keys has in it the power and potency of all music, from the simplest air up to Beethoven's Fifth Symphony. Let him go behind the organ, and elaborately study the very powerful and purely physical forces at work in the interior of the instrument. Let him show, learnedly and laboriously, that currents of air thrown into the pipes produce, according to merely mechanical principles, the wholly physical concussions in the molecular particles of the atmosphere which are concerned in the music. As no merely physical science, by any test known to man, can detect the presence of the musician, let this observer assert that there is no musician independent of the instrument, and that the anthem proceeds wholly from the mechanism of the organ, acted upon by exclusively physical stimulation from without. Let him assert that the hypothesis of an invisible musician is as absurd as the attribution of aquosity to water, or of horologity to a clock. According to this supposed materialistic observer of the organ, there is nothing in the anthem which is not wholly the result of the mechanism of the organ on the one hand, and of the merely physical forces supplied to it by the organ-bellows on the other. Let this naturalistic observer have a great name-among men of his own opinions.

Should we be puzzled by these confident assertions? Not if we held fast to the Ariadne clew of the self-evident, axiomatic truth, that every change must have an adequate cause. We should say that this instrument, being made wholly of matter, is inert. We should assert, in the name of established science, the incontrovertible inertness of all parts of the organ taken alone. We should say that the motion of rough currents of air through it does not and cannot account for the intricate and ravishing melody which captivates our souls by its intelligence, and must have behind it a soul. Mere wood, metal, and ivory cannot utter Beethoven's spirit. Perhaps the air, by the slight pressure of intelligence on the keys, can be ruled into

melody, and made to give all its majestic force to the intelligent weaving of the anthem. But in your organ, as elsewhere, involution and evolution are a fixed equation. You bring out of it only what you put in. Your musical instruments will throw no Beethoven into the air, unless there is a Beethoven at the keys.

Such, my friends, is the stern outline of the ineffaceable contrast between the body and the soul. The distinction between matter and mind is a gulf as vast and impassable in physics as in metaphysics. The soul wears Gyges' ring. It is, indeed, invisible to the microscope, and intangible to the scalpel. But there are mysterious molecular motions in the nervous substance of the brain. Neural tremors fill the keyboard of the body. Undoubtedly there is a perfect correspondence between these tremors and the anthems of thought and emotion, in your Homer, your Demosthenes, your Cæsar, your Milton, your Shakspeare. But the parallelism is not identity. Motions and forces are not the same. The keys in motion are not the music. Physical forces play through the brain; but they do not sing, unless modulated by the ineffable touches of the keys. Just as surely as you, from the structure of an organ, may infer the necessity of a wholly exterior agent to move it, so, from the structure of the nervous system, we must infer the necessity of a wholly external agent to set it in action.

In what I am about to put before you I have the authority of Frey, of Stricker, of Ranke, of Kölliker, of Carpenter, of Beale, of Dalton, and of Draper.

1. In the nervous mechanism there are two kinds of fibres, called by physiologists the automatic arcs, and the influential arcs.

We have here a representation of the simplest kind of nervous fibre [illustrating by a figure upon the blackboard],-the pendent curve of a nervous thread, one end in contact with the external surface of the body, and the other connected with this muscular tissue. If you please, the bioplasts weave all that. Perfectly simple as the structure looks, it is a miracle. Can you make anything like it? Here is your muscular fibre, which has the peculiar quality of contracting under nervous stimulus. Here is your nervous cord, which transmits strange influences that cause contraction when they are received upon this muscular tissue. One test by which true is to be distinguished from false science is, that the former does, and that the latter does not, concern itself carefully with beginnings. Remember, that, even in this automatic nerve, motions and forces are not the same. Muscular contraction is an effect of physical forces only as these act on mechanism arranged before the forces themselves came into play. Your miraculous brain is first woven by your bioplasts. You say mind is the result of the mechanism of the brain; but the mechanism of the brain is the direct product of bioplasmic action.

Of course, I am ready to admit, that, if you touch a portion of this automatic nervous arc with a galvanic current, you will produce contraction there in the attached muscle. Electrical stimulation of such a nerve may produce a contraction of the muscle even after the man

is dead. But what wove that nerve? What wove that contractile tissue?

Beyond this simplest structure, the next higher in the development of the nervous system is what is called the cellated nervous arc. We see it here, a pendent curve as before; but now with a very large bead, or mass of nervous matter with bioplasts in the middle of it, is hanging at this point. It is yet true that irritation here produces contraction there. What influence, then, has this nervous centre upon the transmission of this nervous force? The books say that there is no proof that the nervous influence is changed in quality by its passage through one of these simplest ganglia. You may single out a nerve arc of that primitive style, and irritate it by an electric current on one side of this large bead or ganglion, and you will produce contraction in the muscle just as before. You irritate this side beyond the great bead, and you produce contraction.

But a third step in the development of the nervous system does introduce a change. Many of these nerve-centres are tied up to other nerve-centres [illustrating by a figure in which the ganglion of the nerve-arc was connected with another ganglion]; and in a nerve with its ganglion connected in that style with another ganglion, a portion of the influence transmitted through this complex nervous inass is thrown off into this other complex nervous mass. Your physiological authorities call the latter a registering ganglion. This transmission of nervous influence into the registering complex of nervous matter may be very inadequately illustrated, Professor Draper says, by a faucet with three stops, or by a mirror with a portion of the isinglass taken off the back. The light is in part reflected and in part transmitted. Thus this registering mass of nervous matter retains a portion of the force sent through this nervous arc; and, in an animal possessing this nervous mechanism, there will be memory, or something equivalent to it.

Thus far we have seen only what is called the automatic nervous mechanism. Please fix in your minds, gentlemen, the simplicity of this structure, and, when a more complicated mechanism is outlined in connection with this, keep vividly before your minds the contrast between the two.

All established science is agreed that there are automatic and also influential arcs in the nervous system, and that the contrast between the two things is as marked as that between their accepted scientific

names.

In the higher animals there is added to the simpler automatic part of the nervous system a far more intricate structure, called the influential nervous mechanism. Professor Draper represents the contrast between the automatic and the influential part of the nervous system by this ideal figure,2 which I here reproduce line for line. It is substantially a lower curve and an upper curve--the one automatic, the other influential, and the two bound together by nervous threads. In all physiology, outside the supreme topic of

1 Professor J. W. Draper, Human Physiology, p. 380.

2 Ibid., p. 282.

bioplasm, I know nothing which is so suggestive as this contrast between the automatic and the influential nerve-arcs. Here, assuredly, is a majestic mount of vision upon which the philosophy of the relations between body and soul, matter and mind, must often pace to and fro.

2. Plants and many animals possess only the automatic arcs.

3. Such organisations as possess only the automatic arcs are automata; and, although they have life, they cannot, in the strict sense of the word, be said to possess souls including free-will and conscience.

The contrast between the influential and the automatic is that between freedom and necessity. It is that between man, with the power of choice, and your poor honey-bee, who is supposed to work as an automaton. The bee has not the influential arc: it has only the automatic nerves. Accordingly, by instinct it has built its cell in the same way age after age. Two bees under precisely the same circumstances will do precisely the same things.

But this upper arc, which is possessed by man, is called influential, and not automatic, because it is the seat of activities of a free sort. This is the keyboard of your invisible musician: this is the white ivory shaped by no mortal fingers, and on which life plays.

Gentlemen, I have been accused of being rhetorical; but a man who wishes to dazzle by rhetoric does not talk in twenty-eighthlies and forty-ninthlies, as I have sometimes done. Any one, however, who wishes to convince by cool precision, very naturally employs numerals. You will allow me, therefore, to number the points of a discussion, which must be crowded, and which would nevertheless be clear.

Just here expose themselves in more than glimpses the fascinating questions as to the difference between instinct and reason, and as to the immortality of instinct. Animals that possess only the automatic nerve-arcs have only instinct for their guidance: they have life, but not free wills and consciences. Later in this course of lectures, I shall discuss the question, whether, after death, there is a survival of the immaterial principle in animals that are mere automata. Here and now I emphasise only this broad distinction between the influential and automatic nerve-arcs, a physical fact, without any haze either in its margin or its contents. God materialises. In the universe of forms, as well as in that of forces, the Divine language has no empty syllable. Perhaps this invisible musician, with Gyges' ring on his finger, has not been left without a witness of himself in the whitish-gray keyboard of the human organ. Perhaps the contrast between the automatic and influential nervearcs is just as important a fact in the instrument God has made as the distinction between your musician and the man who moves the bellows behind the organ is in the instrument man has made. Among the automatic and influential nerve-arcs, all philosophy ought to stand listening with hushed breath.

4. Man possesses in abundance both the automatic and influential

arcs.

5. Whatever animal possesses the influential arcs has a depository, magazine, or reservoir of force not dependent on external impressions.

Aristotle noticed with great keenness of interest the fact that men awake before they open their eyes. Professor Bain regards that circumstance, with which we are all familiar, as one out of thousands of proofs that external irritation is not necessary always to internal activity.

By the way, Aristotle was accustomed to assert that the most interesting portion of human knowledge is that which refers to what he called the animating principle of physical organisms. We are beginning to think, I hope, that what is called bioplasm is the most interesting by far of all the objects known to physical science. That, in substance, is an opinion two thousand years old. Aristotle defined the animating principle as the cause of form in organisms. This to him was the most alluring of all the topics open to Greek philosophy. He said often, that, if we ought to be interested in a theme in proportion to its dignity, certainly nothing could be more entrancing than the study of the animating principle.

6. In man the influential arc is the seat of intellect, free-will, and conscience.

7. But, as man possesses the automatic arc also, many of his actions are automatic.

over;

We must expect to find in some animals which have a much more perfect automatic nervous mechanism than man, instincts, and, apparently, spontaneous movements, of the most marvellous kinds. I am not asserting that man is not in some respects an automaton; but he is by no means as good a one as might be chosen if the power of automatic nervous action is to be shown. Professor Huxley went before a great audience at the Belfast meeting of the British Association for the Advancement of Science, and took a headless frog, and put it on the back of his hand, and then turned his hand slowly and the frog kept his place till the hand had been reversed, and the frog stood in the palm.2 Now, said Professor Huxley, is there any will concerned in that? Is not this the result of purely physical stimulation of the frog's nerves? Have we not here an automaton? He meant to puzzle the world about the freedom of the human soul. But the bioplasts wove that frog too. After the automatic mechanism is woven, such results are very well known to follow the action of the merely automatic part of the nervous system. A frog with its head cut off you may put on the back of your hand, and you may turn the hand over, and the frog will keep its place meanwhile without assistance, and stand on your palm. Of course, there is no action of the cerebral hemispheres there. The irritation of the feet has such an effect as to cause the muscles to enable them to cling to their support; just as, while the perching bird sleeps, the perch itself stimulates to action the muscles that cause it to be clasped by the

1 Aristotle de Anima, passim.

2 Huxley's Address on the Question, Are Animals Automata?

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