CHAPTER IV. GEORGE H. LEWES' THEORY OF MIND AND THE HE advocates of this school-with George most cogent arguments and experiments against the two former ones. This third school has evidence-vast evidence to support their position, that the brain is not the only organ of mind. They assert that the spinal cord is as much an organ of thought as the brain-it being composed of a like material, showing similar pathological symptoms and subject to the same diseases, both being alike fatal. They hold that there is no good reason for believing that the one is an organ of thought without ascribing a like function to the other; for all arguments in favour of the brain being an organ of mind are as applicable to the spinal cord being also its organ. They produce cases where animals have lived and manifested sensibility after their brains were removed, с but defy any one to produce a case where they had the same power when the spinal cord was removed.. Let us state a case or two in favour of Mr Lewes position. I quote from " Physiology of Common. Life," by G. H. Lewes :-"Some time ago I removed the brain from a frog, and left it on a plate to recover from the effects of ether. The next morning the servant came to me with suppressed alarm, assuring me my frog would escape. 'No, there's no danger; it can't escape-its head is off." But I assure you, sir, it's quite lively; I thought it would jump off the table.' On going up stairs I found the animal in the middle of the room." We read also of a "tortoise which, after the whole cranial cavity had been completely emptied, walked about as usual, and lived for five months." Dr Inman, of Liverpool, "completely emptied the cranial cavity of a frog, yet found the animal quite vivacious; there was no lack of spontaneous movement, and the reflex actions were distinct enough in the eye, eyelid, and other places." Mr Lewes continues:-"I decapitated a frog. and a triton, and merely divided the spinal cord of another triton and frog. The four were placed in the same pan. At first the spontaneous movements of the decapitated pair were insignificant; but on the second day the headless toad was quite as lively and restless as the frog with a head, and the headless triton little less so than his companion with a head." Mr Lewes decapitated another triton, and its movements were precisely similar to those made before decapitation. He says "that the evidence of spontaneity and choice, of sensibility and volition, is unmistakeable, and that he has verified this many times. "A frog is decapitated, or, better still, its brain is removed. When it has recovered from the effects of the ether, we place it on its back, and touch with acetic acid the skin of its thigh. No sooner does the acid begin to burn than the frog stretches out the other leg, so that its body is somewhat drawn towards it. The leg that has been burned is now bent, and the back of the foot is applied to the spot rubbing the acid away, just as your thumb might rub your shoulder. This is very like the action of the tickled child, who always uses the right hand to rub the right cheek, unless it be held; but when the child's right hand is prevented from rubbing, the left will be employed; and precisely this do we observe with the brainless frog-prevent it from using its right leg and it will use its left. To show this we decapitate another frog, and cut off the foot of the leg we are to irritate. No sooner is the acid applied than the leg is bent as before, and the stump is moved to and fro, as if to rub away the acid. But the acid is not rubbed away, and the animal becomes restless, as if trying to hit upon some other plan for freeing itself from the irritation; and it is worthy of remark that it often hits upon plans very similar to those which an intelligent human being adopts under similar circumstances. Thus, the irritation continuing, it will sometimes cease the vain efforts with its stump, and, stretching that leg straight out, bends the other leg over towards the irritated spot. The brainless frog often chooses a new plan when the old one fails; and an illustration of how sensations guide and determine its movements may be seen in another observation of the brainless frog, when, as often happens, it does not hit upon either of the plans just mentioned, but remains apparently restless and helpless-if, under these circumstances, we perform a part of the action for it, it will complete what we have begun." The animal performs movements, and manifests as much action and volition when its brain is removed as it did previously to that operation. Decapitated frogs also swim vigorously on being thrown into water. "Young rabbits and puppies, when taken from their mothers, manifest their discomfort by restless movements. No one doubts that sensation is present in such cases. Now, if the brain be removed from rabbits and puppies, precisely similar phenomena are observed when these young animals are taken from their mothers." Children are sometimes born without brains. Lallemand exhibited several infants born without brains. "These infants breathed, swallowed, suckled, squalled, and gave very unequivocal signs of sensibility." We read also of "a new-born infant whose brains during the birth had been completely extirpated (to save the mother's life), and was wrapped in a towel and placed in a corner of the room as a lifeless mass. While the surgeon was giving all his care to the mother, he heard, with horror, a kind of murmur proceeding from the spot where the body had been placed, and in three minutes a distinct cry was heard. The towel was removed, and, to the surprise of all, this brainless infant was seen struggling with rapid movement of its arms and legs; it cried, and gave other signs of sensibility for several minutes.". I quite believe if children could survive the shock of craniotomy we would have thousands of cases of brainless infants; but this operation is so violent that very few exist after it. Mr Lewes and this third school, having proved that brain is not the only centre of volition and sensibility, proceed to show that the spinal cord is a centre at least of sensibility. This they prove by an elaborate series of experiments-first, in the lower animals, and then from their observations of human beings with diseased spines. Let us look at their evidence on this point. They divide the spinal cord of a triton, then irritate the head segment-the former part of the animal crawls, dragging the hinder part with it, plainly showing that sensibility extended no further than the cut in the spinal cord. Materialists may assert, "Ha! that is easily explained: the former half contains the brain, and, of course, must have sensibility; whereas the latter half has got its connection with the brain cut off, therefore its sensibility is gone, and the animal must drag it." But (alas! for this argument) |