33. iii) This intricate ganglionic mechanism

"No one now doubts that consciousness has an anatomical substratum, but the great problem of the relation between the two is as far from solution as in the days when little or nothing was known of the physiology of the nervous system. Consciousness has been driven step by step upwards until now it takes refuge in a few thousand nerve-cells in a portion of the grey matter of the brain. The ancients believed that the body participated in the feelings of the mind, and that, in a real sense, the heart might be torn by contending emotions. As science advanced, consciousness took refuge in the brain, first in the medulla and lastly in the cortex. But even supposing we are ultimately able to understand all the phenomena - chemical, physical, physiological - of this intricate ganglionic mechanism we shall be no nearer a solution of the problem of the connexion between the objective and subjective aspects of the phenomena. [...]"

At the regrettable expense of neglecting further colourful references to vivisection (including an intriguing method of removing monkey grey matter using pressurized jets of water), we close our all too brief examination of Prof. McKendrick's contribution to PHYSIOLOGY with the above.

For all the doubtless marvellous advances made by neuroscience in the years that have followed, I have the idea that the problem of consciousness would be couched in similar terms today, and remains unanswered. Similar terms, but I would not expect the same language. There is a certain poetry in the professor's writing, coloured by a certain hint of melancholy and the macabre, and this final section somehow reminds me of Hamlet's soliloquies. George Bernard Shaw, so the Wikipedia informs us, read the ninth edition of Encyclopaedia Britannica in its entirety - excepting the scientific articles. Mr Shaw missed out.

33. ii) More fun with pigeons

"Flourens and the older observers were aware of the fact that as successive slices of grey matter are removed from the cerebrum an animal becomes more dull and stupid, until at last all indications of perception and volition disappear. A pigeon in this condition (see fig. 29), if carefully fed, may live for many months ; to quote from Dalton -

"The effect of this mutilation is simply to plunge the animal into a state of profound stupor, in which it is almost entirely inattentive to surrounding objects. The bird remains sitting motionless upon his perch or standing upon the ground, with the eyes closed and the head sunk between the shoulders. The plumage is smooth and glossy, but is uniformly expanded by a kind of erection of the feathers, so that the body appears somewhat puffed out, and larger than natural. Occasionally the bird opens its eyes with a vacant stare, stretches its neck, perhaps shakes its bill once or twice, or smooths down the feathers upon its shoulders, and then relapses to its former apathetic condition."

Similar observations have also been made on reptiles and mammals, but the latter survive the operation for a comparatively short time. In watching such an animal it is difficult to divest one's mind of the belief that it still feels or hears. It may be observed that it rarely makes movements unless stimulated from without. Thus it may remain motionless for many hours ; but if pushed, or gently touched, it moves. As remarked by Prof. M. Foster -

"No image, either pleasant or terrible, whether of food or of an enemy, produces any effect on it, other than that of an object reflecting more or less light. And, though the plaintive character of the cry which it gives forth when pinched suggests to the observer the existence of passion, it is probable that it is a wrong interpretation of a vocal action ; the cry appears plaintive, simply because, in consequence of the completeness of the reflex nervous machinery and the absence of the usual restraints, it is prolonged. The animal is able to execute all of its ordinary bodily movements, but in its performance nothing is ever seen to indicate the retention of an educated intelligence.""

33. i) Fun with pigeons

"If the cerebellum be removed gradually by successive slices - an operation easily done in a pigeon - there is a progressive effect on locomotive actions. On taking away only the upper layer there is some weakness and a hesitation in gait. When the sections have reached the middle of the organ the animal staggers much, and assists itself by its wings in walking. The sections being continued further, it is no longer able to preserve its equilibrium without the assistance of its wings and tail ; its attempts to fly or walk resemble the fruitless attempts of a nestling, and the slightest touch knocks it over. At last, when the whole cerebellum is removed, it cannot support itself even with the aid of its wings and tail ; it makes violent efforts to rise, but only rolls up and down ; then, fatigued with struggling, it remains for a few seconds at rest on its back or abdomen, and then again commences its vain struggles to rise and walk. Yet all the while sight and hearing are perfect. See fig. 26. It attempts to escape, and appears to have all its sensations perfect. The results contrast very strongly with those of removing the cerebral lobes. "Take two pigeons," says Longet ; "from one remove completely the cerebral lobes, and from the other only half the cerebellum ; the next day the first will be firm on its feet, the second will exhibit the unsteady and uncertain gait of drunkenness.""

(from Professor J. G. M'Kendrick, M.D.'s fascinating contribution to the article PHYSIOLOGY, volume XIX of the 9th Edition of Encyclopaedia Britannica, 1885.)