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'It would be to misunderstand me,' says Mr. Lewes, 'if it were supposed that I do not consider the brain as the principal and dominating organ of all psychical life.

'I have said before that it has the noblest functions, but it does not exclude the other ganglia from their share in the general consciousness. In it all the sensations derived through the senses and viscera are summed up, combined, modified, and in some profoundly mysterious manner elaborated into ideas. It is generalissimo of the whole army, controlling, directing, and inspiring the actions of all subordinate officers. But to suppose that the subordinates have not also their independent functions is a mistake. The generals, colonels, captains, sergeants, corporals, and common soldiers, are individual men, like their commander-inchief, with inferior power and with different functions, according to their respective positions. But if the commander-in-chief be killed, the army has still its generals. If the generals be killed, the regiments have still their colonels. Nay, even a corporal's company may be kept together by an energetic corporal. And this we shall see to be the case with animals when their brain has been removed; each separate part of the organism has its general, colonel, or corporal.'1

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Every nervous centre having, then, a sensibility belonging to itself, a fundamental point,' says Mr. Lewes, 'which appears to me totally inadmissible, is the hypothesis that reflex mechanism is independent of sensibility, and that reflex actions take place without sensation.' 2

He cannot 'refrain from expressing his surprise at the weakness of the evidence which serves as a basis for the celebrated theory of reflex actions.' In order to prove that reflex actions are independent of sensation, it is necessary to prove in the first place that the actions of the spinal cord are independent of sensation; this has never been proved, and has even been placed beyond all evidence.1

It would be beside our subject, and out of our power, to follow Mr. Lewes in his long essay upon reflex actions; we can

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only summarize its principal points, and briefly state the reasons upon which he founds his belief that the spinal cord is a centre of sensation.

1. The opinions of previous physiologists.-The doctrine which recognises sensitive functions in the spinal cord is not new. Robert Whytt held it. Prochaska considered the spinal cord as forming a considerable portion of the common sensorium, and he advanced in proof of it the well-known facts of sensibility manifested by headless animals. J. J. Sue, father of the celebrated novelist, saw that the spinal marrow could, to a certain extent, replace the functions of the brain. Legallois, Wilson, Philipi, Lallemand, and Calmeil arrived at analogous conclusions, under different forms. Thus several facts establishing the sensitive functions of the spinal cord were known, and even a vague conception of their real sense was generally spread abroad, up to the time when the reflex theory arose to explain these facts as the result of a mechanical adjustment. But this doctrine has found its opponents. J. W. Arnold has refuted it. Carus said ironically that the word reflex was a key to open every lock. Schiff maintains that all the cerebral actions, as well as the spinal, are reflex, and depend upon a mechanical arrangement.1

If we pass from historical considerations to the facts themselves, we may consider the evidence which they furnish under two aspects, deductively and inductively.

2. Deductive evidence.-A resemblance of structure implies a resemblance of property, and the ganglionic structure of the spinal cord being of a nature similar to the ganglionic substance of the brain, there must necessarily be a community of property between the two.

"The only ground for denying that the actions of decapitated animals are determined by sensation, is because the brain, or encephalon, is believed to be the sole seat of sensation. To explain the resemblance between the actions of animals with and without their brains, a theory is invented, which says, These actions are reflex. But in the uninjured animal there is reflex action plus the transmission of an impression to the brain, and

1 Physiology of Common Life, vol. ii. p. 231.

it is this which produces sensation; in the headless animal we see reflex action, minus the transmission to the brain.' 1

A gentleman once maintained that there were no gold mines except in Mexico and Peru. His assertions were met by showing him an ingot just come from California. Without being in the least disconcerted, he replied: "This metal, I acknowledge, resembles gold closely; you tell me that it passes for such among the essayers and on the market. I do not dispute that; nevertheless this metal is not gold, but auruminium; it cannot be gold, because gold only comes from Mexico and Peru.'

The decapitated animal defends itself instinctively from the suffering that it is caused, disentangles itself, accomplishes several of its ordinary actions; but they say that it does all this without that sensibility which would guide it if it were not decapitated. This is a case of gold being not gold but auruminium.

Some of

In the Fiji Islands, when a man is about to die, some hours before his death his body is taken out of his house. these persons during that time can eat and speak. But they are reported dead. To eat, to drink, to speak, are involuntary acts of the body, of the empty shell, as the inhabitants of these islands say, but according to them the soul has left it; the theory of reflex action recalls this eccentric belief to Mr. Lewes's memory.2

3. Inductive evidence.-Spontaneity and choice are two palpable signs by which we recognise the presence of sensation and of will. Let us then see if decapitated animals manifest these palpable signs. In the first place, let us look for spontaneity. We should remark, says Mr. Lewes, that a decapitated animal is deprived of the various stimuli which he may receive through the eyes, the ears, and the smell, which determine his movements; he therefore necessarily remains in repose if he be not excited by visceral sensations. He affirms that an attentive and repeated examination of decapitated animals furnishes an abundant evidence of spontaneous actions.3 Let us give an example. Mr. Lewes subjects a strong and healthy triton to various experiments. He touches it, pricks it, burns it with acetic acid, etc. He

1 Ibid. p. 234.

2 P. 236.
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carefully notes the movements of the animal. Next, having decapitated it, he afresh subjects it to the same experiments; the reactions of the animal are precisely similar; it tries to free itself from the pain, to rub off the acid which is burning it. These experiments, to which Mr. Lewes adds a good number of others, lead him to conclude that the evidence of spontaneity and of choice, of sensibility and of volition, does not admit of mistake, and that, consequently, the Spinal Cord is a sentient centre.'1

4. Examination of objections.-After having examined the reasons and the facts in favour of the sensibility of the spinal marrow, we must see what is the value of the evidence set against it. Let us lay aside the first argument, drawn from the universal prejudice that the brain is the only sensorium, because that is simply begging the question. Let us lay aside a second argument, that several actions take place without awaking a consciousness or a distinct attention, such as breathing, digesting, etc. This argument either proves nothing, or it proves too much. An action may be sensational without producing this secondary feeling, generally called consciousness, and in this sense we might even say that thought is unconscious, much more truly than sensations are so. There remains the striking case of maladies or injuries of the spinal marrow, as a result of which nothing is felt below the wounded part. This is the cheval de bataille of the reflex theory.

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But,' says Mr. Lewes, 'when a man has a diseased spinal cord, the seat of injury causes for the time at least a division of the cerebro-spinal axis into two independent centres. For all purposes of sensation and volition it is the same as if he were cut in half; his nervous mechanism is cut in half. How then can any cerebral volition be obeyed by his legs? how can any impression on his legs be felt by his cerebrum? As well might we expect the man whose arm has been amputated to feel the incisions of the scalpel when that limb is conveyed to the dissecting-table, as to feel in his brain impressions made upon parts wholly divorced from organic connexion with the brain.

1

Lewes, Physiology of Common Life, vol. ii. pp. 245-258.

'But, it may be objected, this is the very point urged. The man himself does not feel the impressions on his limbs when his spine has been injured; he is as insensible to them as to the dissection of his amputated arm. Very true. He does not feel it. But if the amputated arm were to strike the anatomist who began its dissection, if its fingers were to grasp the scalpel and push it away, or with the thumb to rub off the acid irritating one of the fingers, I do not see how we could refuse to admit that the arm felt, although the man did not. And this is the case with the extremities of a man whose spine is injured. . . .'1

'It is true that the man himself, when interrogated, declares that he feels nothing; the cerebral segment has attached to it organs of speech and expressive features, by which its sensations can be communicated to others; whereas the spinal segment has no such means of communicating its sensations, but those which it has it employs.

Perhaps

We here terminate this brief explanation of the opinions of our author upon the current doctrine of reflex actions. it seems slightly external to our subject. But the new psychology, which we are endeavouring to exhibit here according to its most eminent representatives, embraces a much wider domain in the reign of facts than the ordinary psychology. It believes that these obscure phenomena into which psychical life has hardly begun to penetrate are in many respects the most curious and the most profitable to study. We have already seen that Mr. Herbert Spencer assigns a place to reflex action in the ascendant evolution of mental life, and the identity of the doctrines of Mr. Bain and Mr. Lewes upon the nature and the seat of the common sensorium must also have been remarked by the reader.

V.

The remainder of the work is devoted to the senses and sensations, to sleep and to the phenomena of heredity.

""How many senses have you?" inquired the traveller from

1 Ibid. pp. 263-264.

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