Henry de Varigny

“ By HENRY DE VARIGNY.
"WHEN the one who listens does not comprehend, and the one who speaks understands as little, you have metaphysics," says Voltaire. Taking this as a true definition, we may say that there has been, and yet remains, much metaphysics in the treatment of the functions of the brain. But the difficulties in cerebral physiology are great. There is divergence of hypotheses, the facts themselves are not settled, and contradictions abound. ”

“ Experiments that produce prompt paralyzing effects are more numerous than those which excite the functions of the convolutions. But the most preferable one, and that adopted by Ferrier, is the method of limited ablation. By it lesions can be more circumscribed, it affords a sure means of control, and hence it has come largely into use. Electricity is the only process for exciting the functions to greater activity; and since it has been much opposed, and is the sole support of the theory of cerebral localization, we must defend its legitimacy. ”

“ Neither medicine nor physiology opposes the use of the clinical method in cerebral localization. But only circumscribed lesions that have little or no tendency to become general, or to act at a distance by compressing the brain, or otherwise, can come to the aid of our theory. When there is a lesion of the cortical region of the brain which fulfills these conditions, the resulting symptoms may be of two orders—either stimulative or paralytic of the true function. ”

“ The middle region of the superior face of the brain appears to be the motor region. In fact, limited lesions of this region bring on marked troubles in the motor innervation of the body, such as monoplegia, or limited paralysis, or equally limited spasms. Putting aside those cases where the lesions cause general trouble, and regarding those where the symptoms are limited, we come at a constant relation between certain lesions and certain troubles. In ocular monoplegia, the eye can not be controlled by the will. ”

“ Again, it is the arm, forearm, or hand that moves in various ways, and to different ends; sometimes there is a combination of movements, like those required for swimming or prehension; the fingers may lock together with force, as if to retain an object, or extend themselves with a lively movement, as if to scatter something. It is probable that, if our instruments were more perfect, we should find in each center a number of subordinate centers for the execution of single movements, or the moving of a single muscle. ”

“ But, since, as the galvanometer shows, the electricity is diffused over neighboring centers, what right have we, it may be asked, to assert that the movement observed, when a certain center is excited, is due to that excitation, when neighboring centers are also excited? We reply that to these facts we can oppose other facts. On removing the electrical conductors scarcely a centimetre, we excite perfectly definite unlike movements, although the current is diffused as before. ”

“ As the terminations of the nerves of sensation are specialized, in exciting the centers we produce, subjective sensations, like those caused by cerebral maladies, in which the intellect refers to the outward world the origin of sensations, of which the cause is in the brain; and, whether voluntarily or by reflex action, the animal operated on by electricity shows by evident signs the nature of the sensations he experiences. By means of counter-verification we determine the existence and topography of a certain number of centers which Ferrier has studied with great care. ”

“ Compress the eyeball, you excite the optic nerve and get the sensation of light; auditive nerves give sensations of sound, and so for all the nerves of special or general sensibility. If, then, in the brain we excite the motor region, the origin of the motor nerves is irritated, and we get movements; excite the sensitive region, and in place of movement we have sensation owing to the connection of these nerves with sensitive cells. ”

“ These are the two opposed symptoms that we produce experimentally by electrization and ablation of the substance of the convolutions. It goes without saying that the symptoms vary with the locality of the lesion: the intellectual region gives delirium; the motor region, spasms; the sensitive region, subjective sensations. The symptoms of functional paralysis are also diversely represented by mental feebleness, motor paralysis, and anæsthesia limited to one sense. A lesion frequently presents both orders of symptoms, which succeed each other, or alternate, according to its nature. ”

“ Disease of the cerebral centers may give no further symptom than enfeebled sensibility, which might pass unperceived. Lesions of the motor region often result not in total paralysis but in slight paralysis—a feebleness and not an abolition of the functions. But there are cases where lesions of the sensitive region are accompanied by less equivocal symptoms, and it is from these that we affirm localization. ”

“ The general idea of the relations of the brain and spinal cord is that the brain commands and the cord obeys. The brain requires such or such a movement, and the cord, working unconsciously, coördinates the elementary and individual movements required to produce the desired effect. ”

“ Running is a reflex act, that does not require the intervention of the centers. But, while the learned dog could use his legs, and go and come, he could not give his paw. This was a superior, voluntary act, which could not be performed in the absence of the corresponding center. It is in this differentiation of the organs of voluntary activity from those of automatic activity that we find the explanation of so many singular facts which at first sight seem to contradict the theory of localization. ”

“ It produces paralysis, and monkeys rarely or imperfectly recover from these lesions, while inferior animals, as the rabbit and Indian pig, recover; thus showing that the voluntary centers are more important in monkeys than in lower animals.
Such are the facts on which we base the existence of a motor region in the brain. Putting aside all questions of interpretation, it is undeniable that there is a region in the brain where stimulation produces movements varying with the zone or center excited. ”

“ Irritating lesions provoke spasms when applied to the motor region, subjective sensations when applied to the sensitive region, and delirium when they affect the intellectual region. Paralyzing lesions in the motor region paralyze the normal action, and in the sensitive and intellectual regions bring on anæsthesia and mental depression. But this division applies only to immediate results, for it is not rare to see a lesion, whether experimental or in clinic, provoke symptoms of irritation in the beginning, followed by paralytic symptoms, and reciprocally. ”

“ In the order of time, the first and the most practicable is the experimental method, which consists in observing the brain through openings in the skull and exciting the convolutions or removing them according to the end proposed. ”

“ The central mass, partially separated from its outer covering by the lateral ventricles, is composed of two round bodies, formed of gray nerve-cells—the active part of the nervous system. The office of these rounded ganglia seems to be to strengthen the impressions that come from without, or from stimulated parts of the brain itself, and they may take part in automatic actions. ”

“ The presence of a third, or intellectual region, is proved, as far as it can be, by experiments on the lower animals. It is difficult to understand the mental action of a dog, Indian pig, or even of a monkey. Ferrier observed numerous facts tending to establish the intellectual function of the anterior region of the brain. Electricity could hardly be employed in these researches ”

“ Next to this zone, we can in the same way find the limits of others presiding over other movements. The influence appears greatest at the center of the zone: exciting the periphery sometimes produces a light supplementary movement belonging to a neighboring zone. The special centers or zones being very near together, our means of electrizing them are not perfect enough to prevent a slight diffusion of the current into neighboring centers and faintly exciting them. To get precise separate effects we must excite the center of the special zone. ”

“ They are intermingled like the gustative and olfactive sensations. Electricity causes movements indicating unpleasant tastes and odors, and extirpation of the parts ends these sensations. The animal will respire odors, or taste savors that in the normal state would make him fly about the laboratory, and it all passes unperceived. Still more hypothetical are the centers of the organic needs of hunger and thirst, and more yet those of sex, but Ferrier's arguments are strong in favor of their existence. ”

“ The frontal region is greatest in man along with the predominance of reason and logic, while in women, who are dominated by their sensibilities, the occipital region prevails. We may cite to the same point the researches of Bordier on the skulls of assassins, of Luys on the brains of fools and idiots, of Bénédikt on the brains of criminals, of Lombroso on the characters of habitual criminals. ”

“ It is true that in cerebral pathology there is great difficulty in separating the essential from the accidental, and distinguishing cause and effect among a plurality of causes. Besides, it frequently happens in cases of cerebral disease that at the autopsy no appreciable lesions can be found. ”

“ The excitation of the convolutions nearest to this ganglion gives the least results; sometimes no movement at all. Unless we admit that the effects are directly as the resistance, which is absurd, downward conduction can not be affirmed. 2. Braun has demonstrated that a section of the white fibers below the excited points, interrupting the physiological continuity, does not arrest electrical conduction sufficiently to prevent movements. ”

“ Happily there are others more scientific and more conclusive. Take the celebrated crowbar case, where a young man, who was blasting, had a pointed bar of iron about three quarters of an inch in diameter and weighing three pounds, driven, by a sudden explosion, upward through his head. ”