by John van Wyhe
William Carpenter, Principles of mental physiology, 1874, Appendix pp. 709-722.
- - - - - - - - - - - - - - -
THE whole of the foregoing Treatise was in type, when the Writer became acquainted with the remarkable results of the Experimental Researches which have been recently prosecuted by Dr. Ferrier into the Functions of different parts of the Brain.* Of these results, some afford full confirmation of certain general doctrines set forth in the preceding pages, giving to those doctrines an unexpected definiteness and extension ; others are clear additions to our previous knowledge, which are not only important in themselves, but valuable as affording a clue to further inquiry ; whilst of others, again, the precise meaning seems at present obscure. As none of them, however, appear to the Writer in any way opposed to his previous teachings, he has thought it preferable, in the present stage of the inquiry, to leave these as they stand ; and to give a separate account of Dr. Ferrier's results, so far as they have yet been made public, with the conclusions which they at present seem to himself to justify.
Dr. Ferrier's researches were made by the localized application of an Electric current to different parts of the Cortical substance of the Cerebrum, and, to other ganglionic centres forming part of the Brain-; the animal having been previously rendered insensible by Chloroform, so that the movements excited by this stimulation may be regarded as the direct products of the physical changes it induced.
The method of applying Electricity found most effective, was that which is known as faradization; namely, the use of the interrupted current of an induction-coil, which could be increased or diminished at pleasure to meet the requirements of the case. As a rule, the current was not stronger than could be borne without great discomfort on the
* Medical Reports of the West Riding Lunatic Asylum, vol. iii., 1873.
710 Appendix. Dr. Ferrier on the Brain.
tip of the tongue; but very considerable variations in its tension were found necessary, in order to produce the same effects in different animals, and at different times in the same animal. These variations ' -were obviously related in part to the condition of the Blood-circulation : the excitability of the Nerve-centres being levered alike by the effect of the " shock " of the severe operation necessary to expose the brain to the requisite extent, -which enfeebles the action of the heart (§ 41) ; by the inevitable loss of Blood, which both directly diminishes the supply, and reduces the heart's action ; and also by the depressing influence of the continued administration of chloroform upon the heart's action. It thus came about, that after great haemorrhage, and -when the brain no longer showed the pulsation which marks the influx of successive waves of blood, the strongest faradization failed to stimulate. But, again, the excitability of the nerve-centres was further depressed by the direct influence of the chloroform ; though this seems to be much less strongly exerted upon the Motor, than it is upon the Sensorial centres. And, lastly, the excitability was progressively reduced by repeated stimulation ; so that at last no movement could be called forth, though the current was much increased in strength. Yet even then, after an intermission of the experiments, during which the use of the chloroform was suspended, and the powers of the animal were refreshed by food and by the respiration of pure air, the excitability was found to have been restored. This is obviously in full accordance with the principle stated in (§§ 404-2) ; for while the nutritive components of the blood supply the materials whereby the nerve-substance generates and repairs itself, audits "potential energy" accumulates, it is by the combination of the oxygen of the blood with those materials, that the potential is converted into actual energy (§308).
The faradization of the cortical substance of the Cerebrum immediately produces an intense hyperaemia that is, a greatly-increased flow of blood through its closely-compacted plexus of minute vessels. This is made apparent in two ways ; first, in the increase in the size of the vessels, which is obvious to the eye; and second, in the profuse flow of venous blood that takes place from the great sinuses, which, in the quiescent state of the brain, had ceased to bleed. Several applications of the electrodes to the cortical substance of the Cerebrum in rabbits, convert it into the likeness of that morbid growth, mainly consisting of blood-vessels and connective tissue, which is known as "fungus haematodes.
The first set of Dr. Ferriers experiments had reference to the pathology of Epilepsy ; and were made by applying the two electrodes to
Relation of Nerve-Force to Blood-supply. 711
points of the Cerebral surface at some distance from each other. This application excited either partial or general convulsion; the most severe fits being induced when the electrodes were applied at the greatest distance.
"In all cases, " says Dr. Ferrier, ' ' whether the fits were partial or more general, the immediate antecedent was an excited hyperaemic condition of the cortical matter of the hemispheres. The irritation was entirely confined to the surface of the hemispheres ; the electrodes being simply applied, without causing mechanical or deep-seated lesion." And not only was there in every case a distinct interval between the application of the electrodes and the first convulsive movement; but. there was occasionally "a distinct interval of time after the withdrawal of the stimulation, before the condition of the grey matter had reached the pitch of tension requisite for an explosive discharge. This, of itself is sufficient to show that the effects were. not due to conducted currents or direct stimulation of the motor nerves of the muscles, but to an abnormal excitability or irritability of parts, whose function, it might be inferred, was to initiate those changes which would result in normal contraction of the muscles affected."(Op. cit., p. 39.)
Nothing, it must be obvious, could more strikingly illustrate the . principle, that while the ordinary Circulation suffices to keep up the nervous tension of the ganglionic centres to the point required for motorial discharge by automatic or volitional " closure of the circuit," the higher state of tension induced by hypermia is itself sufficient to produce spontaneous motorial discharges (§§ 308-311).
It seems to the Writer that the above principles may be fairly extended, to all the cases in which local faradization produced special motor results ; for although the immediateness of these results in the state of normal excitability might seem to indicate they proceeded from direct stimulation of the ganglionic nerve-substance itself, yet when the excitability is [depressed yby exhaustion, a distinct interval is perceptible. And that the "expressive" movements excited by the localized faradization really depend (like the epileptic convulsion) upon the hypermic state which it induces, seems to be further indicated by their frequent persistence after the discontinuance of the stimulation ;a dog, for example, continuing to hold up his head and wag his tail, or to utter cries as of pain (though completely stupefied by chloroform), after the withdrawal of tie electrodes from the respective centres of these actions. For this could scarcely be the case, if the stimulus acted directly on the nerve-substance ; whilst it is quite consistent with the fact that the hypermio state does not immediately subside. And further, it? is a consideration of no small importance, that no motor effect is produced by the faradization of the fibres which make-up the medullary substance, of the Cerebrum, which might be expected to respond to the stimulus if
712 Appendix.Dr. Ferrier on the Brain.
it acted directly upon the elements of the nerve-tissue, as in the galvanization of an ordinary nerve.
The general characteristic of the Movements called forth by the local stimulation of the cortical substance of the Cerebrum, is that they are such as involve the co-ordination of several distinct muscular actions ; and resemble those which, in an animal in possession of its senses, we should regard as expressive of Ideas and Emotions.
Thus, in a Cat, the application of the electrodes at point 2 (Fig. 14) caused "elevation of the shoulder and adduction of the limb, exactly as when a cat strikes a ball with its paw ; " at point 4, " immediate corrugation of the left eyebrow, and drawing downwards and inwards of the left ear;" at point 5, "the
animal exhibits signs of pain, screams and kicks with both hind legs, especially the left, at the same time turning its head round and looking behind in an astonished manner ; " at point 6, " clutching movement of the left paw, with protrusion of the claws;" at point 13, "twitching backwards of the left ear, and rotation of the head to the left and slightly upwards, as if the animal were listening ;" at point 17, "restlessness, opening of the mouth, and long-continued cries as if of rage or pain ;" at point 18 (on the under side of the hemisphere, not shown in the figure), "the animal-suddenly starts up, throws back its head, opens its eyes widely, lashes its tail, pants, screams and spits as if in furious . rage ; " and at point 20, " sudden contraction of the muscles of the front of the chest and neck, and of the depressors of the lower jaw, with panting movement. " Similar results were so constantly obtained, with variations obviously depending upon the degree of excitability and the strength of the stimulus, that the localization of the centres of these and other actions was placed beyond doubt ; the movements of the paws being centralized in the region between points 1, 2, and 6 ; those of the eyelids and face between 7 and 8 ; the lateral movements of the head and ear in the region of points 9 to 14 ; and the movements of the mouth, tongue, and jaws, with certain associated movements of the neck, being localized in the convolutions bordering on the fissure of Sylvius (b), winch marks the division between the anterior and middle lobes of the Cerebrum,the centre for
Localized Functions of Cerebral Convolutions. 713
_ opening the month being in front of the under part of the fissure, while that which acts in closure of the jaws is more in the fissure.
A similar series of experiments on Dogs gave results that closely accorded with the foregoing ; allowance being made for the somewhat different disposition of the convolutions, in accordance with the different habits of the animals, showing itself in the higher development of the centres for the paw in cats, and for the tail in dogs.
Thus when the electrodes were applied at point 9 (Fig. 15), " the tail was moved
wing remarkable series of actions :"It began wagging of the tail and spasmodic twitching of the left ear. After the cessation
of the more violent spasms, the animal held up its head, opened its eyes wide with the most animated expression, and wagged its tail in a fawning manner. The change was so striking, that I and those about me at first thought that the anima] had completely recovered from its stupor. But notwithstanding all attempts to call its attention by patting it and addressing it in soothing terms, it looked steadfastly in the distance with the same expression, and continued to wag its tail for a minute «r two, after which it suddenly relapse . into its previous state of narcotic stupor." The application of the electrodes to point 21 produced "drawing back of the head and opening of the mouth, with a feeble attempt at a cry or growl (the animal very much exhausted). Repeated applications of the electrodes to this point and its neighbourhood caused whining and growling noises," like those which a dog makes in its sleep, and which are supposed to indicate that it is dreaming.
Similar experiments having been made upon Rabbits, the results were again as accordant as it would be fair to expect ; especially con-
714 Appendix.Dr. Ferrier on the Brain.
considering the difficulty in exactly localizing the different centres, which arises from the absence of the landmarks afforded by the convolutions. It is curious that in this animal the centres of the mouth-movements seem to be the most highly developed; when- these (2, 7, Fig. 16) are faradized. " there are munching movements of the upper lip, and grinding of the jaws, as if the animal were eating vigorously."
Dr. Ferrier has since made a series of experiments on the Monkey;, of which the details are as yet unpublished, but which seem to be yet more> remarkable than the preceding, in the far greater variety of the movements called forth from different centres, and their more distinctly expressive character. These results will also be of peculiar interest, on account of the close conformity which the simple arrangement of the convolutions in the Monkey bears to their more complex disposition in the Human Cerebrum (§ 106). They correspond with those of the previous experiments in this important particular that those centres of movement which may be regarded as giving expression to attributes that Man shares with the higher Mammalia, are all located in the anterior lobes and the anterior portion of the middle lobes, the part of Man's Cerebrum which corresponds with the entire Cerebrum of the lower Mammalia (§ 106). In the Cat and the Dog, which have the middle lobes fully developed', stimulation of their posterior portion produces no respondent movement. And not only is this the case in the Monkey also ; but the whole of the posterior, lobe is similarly irresponsive, as is also that front portion of the anterior lobes, which, in all the higher Mammalia, as in Man, is produced by that forward as well as lateral development, which markedly distinguishes it from the corresponding part of the Cerebrum of the Rabbit. What may be the special functions of these parts, we can scarcely do more than guess at ; but the negative fact just stated may be considered as a decided confirmation of the conclusion arrived at by the Writer twenty-seven years ago, on the basis of Comparative Anatomy and Embryology*,that the posterior lobes of the Cerebrum are the
* See his Review of " Noble on the Brain and its Physiology," in the "British and Foreign Medical Review," for October, 1846.
Functions of Lower Ganglionic Centres. 715
instruments, not (as maintained by Phrenologists) of those passions and propensities which Man shares with the lower Animals, but of attributes peculiar to Man, which we fairly may suppose to consist in such Mental operations of a purely Intellectual character as do not express themselves in bodily action.
Before considering the further conclusions to be drawn from the results of Dr. Perrier's experiments on the Cerebrum, it will be well to take into account those which he obtained from the application of the like stimulation to other ganglionic centres forming part of the Brain. When either of the Corpora Striata (§ 89) was thus excited to activity, an immediate and rigid pleurosthotonos, or bending of the body to one side, was excited in the opposite half of the body ; 'the head being made to approximate the tail, the muscles of the face and neck being thrown into rigid tonic spasm, and the fore and hind limbs fixed and rigidly flexed. Apparently every muscle or group of muscles represented in the convolutions, along with, the lateral muscles of the body, were stimulated to contraction from the corpus striatum ; the predominance of the flexors over the extensors, however, being very marked. Similar excitation of the Tlialami Oplici, on the other hand, gave no motor result whatever ; from which it may be concluded that they have no direct connection with movement. That the irritation did not call forth cries or other signs of pain, might be supposed equally conclusive against the idea that these ganglionic centres are instrumentally connected with sensation ; but when it is borne in mind, not only that the animal was under the influence of chloroform, but that the connection of the irritated Thalamus with the Cerebral centres of the movements which express pain had been destroyed in order to expose this ganglion, the absence of any such, expression seems adequately accounted for.Experiments on the Corpora Quadrigemina (or Optic Ganglia) were chiefly made on Rabbits, in which these centres are relatively very large and are easily exposed (§ 85). The application of the electrodes to the anterior tubercles immediately calls forth a violent opisthotonos, or backward flexure of the body ; so that, if the animal be not tied down, it executes a backward summersault which throws it off the table. The jaws are always violently clenched, and the pupils are dilated. These results do not militate against the idea of the connection of these ganglionic centres with the sense of Vision, which seems to be well established by other evidences ; but they show that they are also motor centres, especially for the extensor muscles. Stimulation of the posterior tubercles occasioned noises of various kinds.
Dr. Ferrier's experiments on the Cerebellum have led him to the
716 Appendix.Dr. Ferrier on the Brain.
unexpected conclusion that it is the ganglionic centre of the motor nerves of the Eye ; every kind of movement of the eye-balls,even rotation on their antero-posterior axes,being capable of excitation by stimulating some particular portion of the organ. The localization of the centres of combined movements of the two eyeballs in particular lobules of the Cerebellum in the Rabbit was extremely curious.
Thus, when the electrodes were applied to the median lobe at point 1 (Fig. 17), "the right eye moved outwards, and the left inwards, in a horizontal plane;" at points 2 and 3, the "right eye moved inwards, and the left outwards, on the same horizontal plane. " Thus it appears that the middle lobe regulates those horizontal movements of the eyes which are harmonious but not symmetrical ; and that the upper part of the median lobe, and its middle and lower parts, are in functional antagonism. When the electrodes were applied to point 4 on the left lateral lobe, "the right eye moved downwards and outwards, the left eye upwards and inwards ; " and when the corresponding point of the right lateral lobe was stimulated, "the right eye moved upwards and inwards, and the left eye 'downwards and outwards ; " while conjoint irritation of both lateral points neutralizes both effects. When the middle division of the left lateral lobe was irritated at point 5, a downward movement of the right eye, and an upward movement of the left eye, were combined with a rotation of each globe on its antero-posterior axis, the left in the direction of the hands of a clock, the right in the contrary direction. But when the irritation was applied at point 6 to the lowest division of the left lateral lobe, the two eyes rotated on their antero-posterior axes in the same direction, contrary .to that of the hands of the clock, so that their vertical meridians retained their parallelism.This last action is what takes place automatically when we fix our gaze at any object, and- incline our head to the right side ; the rotation of the eyeballs in the opposite direction serving to keep the image of the object on the same spot of the retina, just as do the automatic movements of the eyeballs in the vertical or horizontal plane, when the head is moved upwards and downwards, or from side to side (§21).
These results throw great light upon the obscurity -which previously enveloped the precise function of the Cerebellum. That it was in some way concerned in the regulation and co-ordination of the Muscular movements, especially those concerned in the maintenance of the equilibrium of the body, has long been a general opinion among Physiologists, based in part on the results of experiments, and in part
Functions of Cerebellum.General Results. 717
upon Pathological observation ; the doctrine of the Phrenologists, who regarded it as the organ of the generative instinct, having been long abandoned as untenable. But of the manner in which this power was exerted, nothing could be said to be precisely known. Now there can be no question as to the intimate relation between the guiding sensations we derive from Vision, and the co-ordination of oui1 ordinary movements of Locomotion (§ 192). In the affection termed "nystagmus," which consists in a restless motion of the eye-balls from side to side, there is a difficulty in maintaining the equilibrium ; and in the state called "locomotor ataxy," in which disease of the posterior columns cuts off the Cerebellum from its normal relation with the Spinal cord, it is impossible for the patient to maintain his equilibrium with his eyes shut (§ 80). So in the giddiness which most persons experience when they have rapidly turned round-and-round several times, it can scarcely be doubted that part at least of the result is occasioned by confusion of those visible perceptions, which would come through the oculo-motorial centres.That this regulation of the movements of the Eyes, and the harmonization with them of the general movements of the body, constitute the entire function of the Cerebellum, it would be premature yet to assert; but Dr. Ferrier's experiments seem clearly to establish the first of these, and strongly to indicate the second, as essential parts of its action.
"We now return to the inquiry as to the import of the experimental results previously detailed, in regard to the localization of Cerebral action in the production of Movement, and its relation to Mental" states.
In the first place, they unmistakably prove the correctness of the doctrine, that the Cerebrum, like the nerve-centres on which it is superposed, has a reflex action of its own ; which manifests itself in the production of co-ordinated movements, such as, in the normal condition of the animal, would be the expressions of Ideas and Emotions called forth by Sensations. The Cortical ganglion is ordinarily excited to activity by the nerve-force transmitted upwards along the ascending fibres from the Sensorium ;, this calls forth respondent physical changes in its substance, which changes excite the states of consciousness that we designate as Ideas and Emotions ; and respondent Movements are involuntarily called forth, which we regard as expressions of those states. The same movements are called forth (as in other instances) by stimulation applied to their motor centres ; which axe now proved to be definitely localized in the Cerebral convolutions.
718 Appendix.Dr. Ferrier on the Brain.
But, secondly, it seems equally clear that these movements are called forth, not by the Mental states themselves, but by the Cerebral changes which are their physical antecedents. For we can scarcely believe that Ideas and Emotions can be- called up by faradization of the cortical substance, in animals completely stupefied by chloroform. And if -we attribute any of those "expressive" actions which are called forth by such localized stimulation, to the states of consciousness they would ordinarily represent,* we cannot refuse the like character to the Epileptic convulsion called forth by the more general stimulation ; a supposition at once disproved by the fact, that in the typical forms of Epilepsy, convulsive movements, such as have now been traced to "discharging lesions" of the Cerebrum.t take place without any] consciousness whatever. Viewed in this aspect, Dr. Ferrier's results obviously afford additional support to the doctrine of "Unconscious Cerebration;" by showing that important Cerebral modifications of which only the results make themselves known, may take place outside the " sphere of consciousness" (§§ 416-418).
In the third place, we seem able to draw from these experimental results a more definite rationale than we previously possessed, as to the automatic performance in Man, of movements which, originally proceeded from intentional direction. For it is clear that in Dogs, Cats, Rabbits, &c., the co-ordinated actions which result from localized stimulation of the Cerebral convolutions,expressing, by the Nervous mechanism proper to each species, the Mental states naturally called up by their sensational experiences,are as truly the " reflex actions of the Cerebrum," as the simpler forms of movement are of the Axial Cord. Now the Nervous mechanism of Man, as has been pointed out over and over again in the preceding pages, forme itself in accordance with the modes in which it is habitually called into action ; - and thus, it may well be believed, any special modes of co-ordinated movement to which an individual has been trained, or has trained himself, come to be so completely the reflex actions of particular
* Dr. Ferrier was himself so much impressed in one case by the intelligent character of the succession of actions thus called-forth, as to speak of it as "evidently an acted dream." But if this was, then every other must be regarded in the same light ; and the Writer fails to see in what the evidence of consciousness consists. It seems to him that it might just as well be said that the headless body of a Frog is animated by a directing Will, when one leg wipes off an irritant applied to the other (§ 67).
f This view of the origin of those forms of Epilepsy which commence with convulsive spasm of the muscles ordinarily put in action voluntarily, is distinguished from those which primarily affect the muscles of Respiration whose centre of action is the Medulla Oblongata, is due to the clinical sagacity of Dr. Hughlings Jackson.
General Results. 719
centres of his Cerebrum, that, if we could stimulate those centres by Electricity, respondent movements of the kind acquired by such special training would be the result. And since we now seem justified in asserting that such movements may be executed unconsciously, we may further regard it as at any rate conceivable that they may be excited unconsciously, even though such excitement comes through one of the organs of Special Sense.
The following statement recently made to the Writer by a gentleman of high intelligence, the Editor of a most important Provincial Newspaper, would be almost incredible, if cases somewhat similar were not already familiar to us : "I was formerly," he said, "a Exporter in the House of Commons ; and it several times happened to me, that having fallen asleep from sheer fatigue towards the end of a debate, I found, on awaking after a short interval of entire unconsciousness, that I had continued to note down correctly the speaker's words. I believe,'" he added, "that this is not an uncommon experience among Parliamentary Reporters." (Compare §§ 71, 194.)The reading aloud with correct emphasis and intonation,, or the performance of a piece of music, or (as in the case of Alberts-Smith) the recitation of a frequently-repeated composition, whilst the conscious mind is entirely engrossed in its own thoughts and feelings, may thus be accounted for without the supposition that the Mind is actively engaged in two different operations at the same moment ; which would seem tantamount to saying that there are two Egos in the same organism.
'But, fourthly, these results entirely harmonize with the view formerly expressed (§§23, 89), that the Cerebrum does not act immediately on the motor nerves, but that it plays downwards on the motor centres contained within the Axial Cord ; from which, and not from the Cerebral convolutions, the motor nerves take their real departure. For although either mechanical or electric stimulation of a motor nerve in any part of its course, of the motor columns of the Spinal Cord, or of the fibrous strands which constitute the upward prolongations of these into the corpora striata, calls forth muscular contractions, no such contractions were excited by the faradization of the fibres of which the medullary substance of the Cerebrum is composed, any more than by mechanical stimulation. And the fact that all the muscles concerned in the ordinary movements of the body can be thrown into contraction by stimulation of these lower centres,the extensors through the corpora quadrigemina, while the flexors predominated when the corpora striata were stimulated,seems to show that the office of the Cerebrum is not immediately to evoke, but to co-ordinate and direct the muscular contractions excited through these antagonistic primary centres ; just as it controls the Respiratory movements whose centre is in the medulla oblongata.
In the fifth place, these experiments throw great light on the " crossed " action of the several ganglionic centres contained within '
720 Appendix.Dr. Ferrier on the Brain,
the skull, -which had previously been a matter of considerable obscurity; some phenomena of disease appearing to show that the motor centres of one side act on the nerves of the opposite side exclusively, whilst others seem to indicate that those of one side may affect the muscles on both sides. Anatomical investigation favoured the latter view, by showing that whilst some of the motorstrands (corpora, .pyramidalia) which connect the Brain with the Spinal Cord, decussate, or cross to the opposite side, others pass continuously downwards without decussation. Now Dr. Ferrier found that the motor action of the corpora striata is strictly limited to the muscles of the opposite side of the body ; being probably exerted solely through the decussating strands. On the other hand, the motor action of the corpora quadrigemina is not thus limited ; the extensors of both sides being called into contraction by the application of the stimulus to either lateral half of the anterior pair ; so that they would seem to act through both the decussating and the non-decussating strands. In his experiments on the Cerebral Hemispheres, again, Dr. Ferrier found the motor action to be generally limited to the opposite side of the body ; though in some movements, particularly those of the mouth, it was obvious that muscles of both sides were put in action. Now it is well known that extensive destruction of the substance of either hemisphere, if resulting from the gradual action of disease, may occur without any obvious loss of voluntary movement; though sudden injuries of a certain severity occasion paralysis of the opposite half of the body, which, however, is usually incomplete and of transitory duration. And Dr. F. inclines to accept the conclusion' drawn by Dr. Broadbent from clinical observation, that the movements which are most independent on the two sides, are those which are most completely paralyzed by injury to one side of the Cerebrum ; whilst those in which the cooperation of the muscles on both sides is required, may be sustained by the action of either hemisphere. Not improbably the great transverse commissure (corpus callosum} here comes into action, enabling either hemisphere singly to do the workto a certain extentof both ; while there seems some ground for the belief that the left hemisphere, which chiefly directs the movements of the right half of the body, is the " driving " side. For in all save "left-handed" persons, any movement which may be initiated by either limb, is almost sure to be initiated by the right : thus in beginning to walk, we almost invariably put the right foot foremost ; and a person desired to hold up his hand, will as probably hold up the right hand.*
* In the well-known case of the murder of Mr. Blight by Patch, in which the
General Results. 721
' But, sixthly, we have to inquire how far these experimental results justify the belief that there is any such localization of strictly mental states, as there is of the centres of the expression of those states in movement. And as to this it must be confessed that we are still very much in the dark,the only fact that seems to afford any clue to the solution of the mystery, being the apparent coincidence between the motor centre of the lips and tongue in the lower animals, and that region in the human Cerebrum of "which disease is so often found to be associated with Aphasia (§ 355). . This association, however, seems by no means so constant as to establish a causative relation between the Physical and the Psychical state ; and a careful examination of the phenomena of Aphasia would probably lead to the conclusion, that several distinct forms of disorder have been grouped under one designation. The typical Aphasia consists (as stated' in § 354), in the loss of the memory of words, or rather of the power of recalling them; 1 the patient understanding what is said to him, but not being able to reply verbally, because he is unable to call to mind the words which would express his thoughts. Such patients are exactly in the condition of the "Biologized" subject (§ 462), who, being assured that he cannot recollect his own name, finds himself absolutely unable to do so. But in other instances, it would seem as if the defect were not so much in the want of the memory of words, as in the want of power to express them. vocally ; and this, not from paralysis of the nerves of speech, but from an interruption to the action of the "Will on the motor centres (§ 312). And although there would seem strong ground for the belief that the memory of particular classes of ideas may be thus localized, yet it would be certainly premature to affirm that either the phenomena of disease, or the results of experiments, at present justify the belief that the region in question is the seat of the memory of words.The analogy afforded by the specialization 'of downward (motor) action, would lead us to anticipate that a like centralization may exist for upward (sensory) action ; and that particular parts of the convolutions may be the special centres of the classes of perceptional Ideas that are automatically called up by sense-impressions; and anatomical investigation, particularly in the lower animalsin which such ideas may be supposed to prevail almost to the exclusion of the intellectual ideas may not improbably throw light on this relation. But in regard to those Mental processes which mainly consist in the selection, classification, sagacity of Sir Astley Cooper enabled him to infer from an examination of the local circumstances, that the pistol must have been fired by a left-handed, man, the prisoner, -when called upon to plead and hold up his right hand, held up his left.
722 Appendix.Dr. Ferrier on the Brain.
and comparison of distinct Ideas (§ 227), whether these processes be carried on volitionally or automatically, it still seems to the Writer just as absurd as it formerly did to suppose that there can be special " organs " for their performance, such as those named Comparison and Causality in the Phrenological system.
* British and Foreign Medical Review, October, 1846.
Back to home page
© John van Wyhe 1999-2011. Materials on this website may not be reproduced without permission except for use in teaching or non-published presentations, papers/theses.