LECTURE BY PROFESSOR HUXLEY ON THE BRUTE CREATION.

Globe, Volume II, Issue 141, 14 November 1874, Page 4

LECTURE BY PROFESSOR HUXLEY ON THE BRUTE CREATION.

On August 24th there was a great assemblage of ladies aud gentlemen in Ulster Hall to hear a lecture delivered by Professor Huxley. Professor Tyndall, President of the British Association, introduced the lecturer as a lover of truth, perfectly fearless in utterance. Although he was a hard hitter, he always struck honorably above the belt, and never condescended to strike a foul blow.

Professor Huxley, who was received with loud cheers, said—The origination of the attempt to explain vital phenomena by purely physical reasonings was due to two persons; the first, William Harvey, who, by discovering the mechanism of the circulation of the blood, and by his no less important labors upon development, laid the foundation of all those purely physical explanations of the functions of sustentation and reproduction to which modern physiologistswerestriving. Theliving body, however, was not only sustained and reproduced, but moved and felt, and the attempt to reduce the complexities of animal motion and sensation to law and order was reserved for a contemporary of Harvey’s, who was, undoubtedly, greatly stimulated by Harvey’s work. This was Rene Descartes, a man who, in his short life, did enough to entitle him to take rank among the chiefs of philosophy, and who was not only one of the greatest and most original mathematicians but also, in the conviction of the lecturer, one of the greatest of physiologists, doing for the physiology of motion and sensation exactly what Harvey did for the circulation. In fact, although Descartes’work had been frequently forgotten, those who had studded the history of science knew that his physiological views were the subject of continual discussion for more than a century after his death. Haller, the greatest physiologist of the 18th century, did little more than reproduce them. David Hartley, in his remarkable essay on man, expressly acknowledged the value of Descartes’ work and its relation to his own. Proceeding to make quotations from Descartes, Professor Huxley showed chat the following prepositions were over and over again enunciated and insisted upon by him : First, that the brain was the organ of sensation, thought, and motion—that was to say, some change in the condition of the brain was the invariable antecedent of the states of consciousness to which these terms were applied. It should be borne in mind that while distinctly stating this view, Descartes had always been regarded as the great champion of the distinctness of the soul from the body, and as the founder of an idealistic scuool of philosophy. Secondly, all the movements of animals was due to the changes of form of a particular kind of matter, to which Descartes gave the general name of muscle. Thirdly, this change of the form cr, as it was now called, contraction of a muscle, caused the motion of the substance contained in certain cords termed nerves, which were connected with the muscle at one end and with the central nervous system at the other. Fourthly, the motion of the matter contained in a motor nerve took place from the central nervous apparatus towards the muscle, and under ordinary circumstances was due to the motion of the motor of the central nervous system with which it was

connected. Fifthly, as the muscles were connected with the central nervous apparatus by motor nerves, so were the organs of sense connected with that apparatus by sensory nerves, and impressions made by outward objects on the sensory organs gave rise to a motion of thesubstaneeof these nerves, which motion took place in a direction from the sensory organ to the central apparatus. Sixthly, the motion of the matter of a sensory nerve transmitted to the brain gave rise to a motion of the matter of the brain itself, and this motion might be transmitted to the motor nerves which took their origin in the brain, and so gave rise to contraction of the muscles to whichthosc motor nerves were distributed. This process of reflexion of nerve motion from a sensory into a motor nerve through the central nervous apparatus might occur without consciousness and without volition, or even contrary to the latter. Seventhly, the motion of the matter of the central nervous organ, excited by the motion of the matter, might give rise to muscular motion only; but it might, and commonly did, give rise to a sensation or state of consciousness. This sensation, however, had no resemblance to the motion of matter, so that we could have no knowledge that our sensations were anything but the symbols of that which excited them. Eighthly, that motion of any given portion of the matter of the brain excited by a sensory impression left behind it a readiness to be moved in the same way in that portion of the matter of the brain ; anything which set this movement going thus gave rise to a reproduction of appropriate sensation. These was the physical mechanism of memory. These eight propositions, which were stated over and over again by Descartes, and most fully and happily illustrated by him, constituted the foundation of all that was at present known of the physiology of the nervous system, and of the relation between physical and mental phenomena. The lecturer then proceeded tc show’ in what manner the advance of knowledge had strengthened and completed the evidence in support of these propositions, and remarked that in estimating the value of Descartes’ work it must be recollected that he was not a mere speculator, but a zealous practical anatomist and physiologist. In one direction, however, Descartes went a step further than most of his contemporaries and successors had cared to do, since it was clear that many and complicated actions of the animal frame might be effected without the intervention of consciousness. What right had we to draw any limit to the capacity of the animal machine to act in a purely reflex manner 1 Since the organism could undoubtedly adjust itself to varying external conditions to a certain extent, was it not possible that this mechanical selfadjustment might account for all the actions of brutes? Why might they not be merely automata—wholly devoid of consciousness ? Descartes saw no reason for limiting the application of his mechanical theory to animal action, and therefore put forward his famous hypothesis of the automatism of brutes. If we attempted to criticise this doctrine by the light afforded by modern investigation, it was surprising to find how far the results of the experimental physiologists went towards justifying the bold and apparently paradoxical hypothesis of Descartes. The results of experiments upon the frog were then detailed by Professor Huxley. * * * If the section was made at a high part, so as to leave the middle portion of the brain in continuity with the spinal cord, while all the rest was destroyed, the frog became capable of executing complicated movements, and particularly a movement of balancing itself which required the most complicated adjustment of all the movements of its limbs. Under these circumstances the frog might be kept alive for months. It remained absolutely passive, apparently insensible; took no food, did not stir from the spot in which it was placed, but all its bodily functions were perfectly normal, If fed artificially,' it swallowed and digested its food; if pushed, it walked or jumped; if thrown into the water it swam; and although it took no note of external objects, yet if an obstacle were placed in its way, and if it was thus stimulated to jump, it directed its course to the right or the left, as the case might be, of the obstacle. The animal, in fact, was precisely in the condition supposed by Descartes of a living machine which was capable of performing all the ordinary actions of life, but which yet lacked a certain portion of its powers, and which from the analogy of what happened in man must be believed to be altogether devoid of consciousness. Moreover, recent observations of the effects of wounds and diseases (a very remarkable French case being particularly referred to by the lecturer) showed that in consequence of certain lesions of the interior of the brain, a man might be reduced to a condition precisely analagous to that of the frog partially or completely deprived of its cerebral hemispheres—that was to say, he might retain his powers of walking, of using his hands, of speaking, of sight to a certain extent, and yet might be absolutely devoid of consciousness—a mere machine capable of being acted upon by appropriate external stimuli, and thereby made to do everything in a purely mechanical manner.