Clinical and Physiological Research on the Nervous System
150 Art. XII.
Science, as well as History, has a tendency to repeat itself.. What was attempted in the eighteenth is now reproduced, with slight modification, in the nineteenth century. Hartley, a disciple of Newton, modestly essayed to demonstrate that all impressions from the external world were conveyed along the nerves to the brain, and thus entered consciousness, by a suc- cession of vibrations and vibratiuncles, either disturbing an imaginary ether universally diffused and locally surrounding the nerves, or by equally imaginary tremors and agitations in the nerves themselves, or in the fibres and fibrillse of which they consist; while Dr Hughlings Jackson lias, for several years past, argued that certain motions, mollar or molecular, it is not clear which, are propagated or ” discharged” along the course of the nerves to specific muscles or sets of muscles, and, indeed, to all parts of the system, and there energise or destroy the functions of these parts in proportion to the nature or force of the discharge, whatever that may be. It must be confessed that these discharges, and the thing, the energy, the aura, the ” destroying or discharging lesions,” are, as yet, as little sus- ceptible of proof as the vibrations or vibratiuncles of Hartley. The main object of this publication appears to be to show that, contemporaneously with the mental, there take place motor actions in the convolutions of the cerebrum, which pass along, or are connected with, remote organs through the medium of efferent nerves, effecting corresponding changes in the motor or physical functions of these organs. As this epitome has been divested of the transcendental language which that school, of which the ardour and originality of Dr Hughlings Jackson legi- timately constitute him the leader, has, we think, unfortunately adopted ; and, as it is possible that the accuracy of our con- densation may be questioned, it may be prudent to quote the words of the formula now given forth.
Dr Hughlings Jackson says, page 7, Preface : ” It is assumed that the cerebral hemisphere is made up of pothing else than nervous arrangements for the co-ordination of impressions and movements; that, in other words, the unit of composition of * On the Localisation of Movements in the Brain, by Dr Hughlings Jackson. this, as of every other nervous centre (the ” organ of mind ” as well as the ciliary ganglion, spinal cord, &c.) is sensori-mofor “an epileptic discharge of a convolution caused ‘convulsion of the arm”’ (p. 6); “The spasmodic deviation of the eyes, spasm of the hand and arm, drawing of the face, and torsion of the tongue, represent in a brutal way a development in vast numbers of the motor elements of the anatomical substrata of visual, tactual, and verbal ideas ; and this amounts to saying that convulsion is as much a symptom of disease of the ‘ or?-an of mind’ as delirium is ” (p. 39) ; and ” I have long believed that not only the movements ordinarily so called, but the movements of arteries and the viscera, are represented in the cerebrum ” (p. 18).
Subordinate to the maintenance of these propositions we’ find in this paper collateral issues and objects, such as a flattering tribute to Hitzig and Ferrier, in friendly forgetfulness that their experiments are still, in the opinion of many mem- bers of our profession, sub judice, and are openly questioned by Burdon Sanderson, Putnam, and others; secondly, a vin- dication of the author’s priority of claim to the discovery of the supposed dual function of the cerebrum; thirdly, that the left brain is the leading or driving side, the side or seat of will, while the influence of the right is automatic?a conclu- sion suggested, perhaps, by Brocas’ “Localisation of Language fourthly, that both hemispheres are educated in expression, and, although the left be the leading side, the right is the seat of perception, educated sensations; and, fifthly, that the anterior part of the cerebrum is chiefly motor, the posterior chiefly sensory, etc., the latter being claimed by the author as an observation of his own. Around all these subjects are grouped illustrations, analogies, parallelisms, guesses at truth, which have occurred to many inquirers, but are still undemonstrated problems. These remarks, however, shall be confined almost exclusively to what the author conceives the central and most important position in his brochure, and which he has elaborated with great solicitude and detail, and to the mode in which that elaboration lias been conveyed ; the position, viz. that co-ordina- tion of impressions and movements affected in the very highest centres the substrata of consciousness ; which may be the streak of light before the dawn, the penumbra of a discovery, but assuredly it is neither the dawn nor a discovery. Had Dr. Hughlings Jackson condescended to employ terms in common use, his postulate might have amounted to this, that certain areas of the brain, the convolutions, for example, subserve to, or are the organs of, movement and sensibility, which come under the cognisance of consciousness through such parts or organs, and miglit have been fairly accepted, or, at all events, dis- cussed ; but, in its present form, it appears to be contradicted at once by Physiology and Pathology?by Dr Hughlings Jack- son’s own pathology, or what he calls ” experiments instituted by disease,” by his doctrine of compensation, remote influence, and so on.
Declining, at present, to enter upon the rather dark and devious path of which the substrata of consciousness, memory of words, ideation, are the goal, it is incumbent to ascertain the author’s precise meaning when using such terms as ” co- ordination of impressions and movements in the convolutions,” and whether he desires to express merely that volitions or con- ditions eventuating in movements, voluntary or involuntary, in remote organs have their origin in the convolutions, or that molecular movements themselves occur in the structure of the convolutions, and are consentaneous with the motive which prompts a motion, and the remote motion itself. Dr Hughlings Jackson might have been misled by what he would call the ” coarse and brutal,” and what we, more mildly, would style the unphilosophical view that a certain incentive or feeling is con- temporaneous with external acts, that something?a ” discharge” ??proceeds from the central brain to the circumferential muscles, &c.,?to adopt the former and perhaps popular theory; but we apprehend that his speculations have compelled him to embrace the latter, as we find: ” For mental states arise during molecular movements in nerve cells and fibres, and there is no more difficulty in believing that theyarise during molecular movements, in nerve cells and fibres representing muscular movements, than during molecular movements in those repre- senting peripheral impressions” (p. 34). Now it is almost needless to affirm that of such molecular movements in cells, &c., even our most sanguine microscopists have afforded no proof nor probability. But supposing that such a “pons asinorum” had been crossed?supposing that the convolutions had been proved to be sensory motor, and that they were centres of co- ordination, we find it impossible to reconcile such a doctrine with Dr Hughlings Jackson’s admissions: 1. “That part of the body is not necessarily paralysed when corresponding part of brain is destroyed, as neighbouring parts act for it;” for example, when the corpus striatum is injured, the adjoining convolutions exercise their conservative influence over the said muscles. 2. It is true that there is a sort of reservation in the affirmation that ” discharges are not more isolated than the action of single muscles thus, hemiplegia is referred to a destroying lesion in the corpus striatum, and convulsion to a discharging lesion of the adjoining convolutions, which, when both nervous diseases occur unilaterally or alternately, may be regarded as another example of this convenient compensatory law. Again, com- pensation is declared not to be absolute ; when parts of the brain are destroyed, and are not followed by any obvious symptoms, it is conjectured that the loss of the muscular sense may have taken place! These difficulties are enhanced by the following considerations :?
I. These statements point rather to the diffusion of the relation, whatever that may consist in, subsisting between the convolutions and distant parts, than to its localisation. II. In discussing the effects of a tumour, situated in the white matter about the middle of the lateral ventricle, it is .admitted that these must have been remote?in other words, that they were transmitted through healthy portions of the brain to that apparently involved by the structural disturb- ance.
III. And in this section we detect a ” destroying lesion” to the whole of our author’s argument, as he confesses that although the lesion in unilateral convulsions may be found in the region of the corpus striatum, yet, ” occasionally no local morbid change can be found in any part of the brain “?a con- fession common to every one who has spent much time in the dead-house. In connection with this part of the inquiry, the Appendix may be adduced as militating against many of Dr. Hughlings Jackson’s favourite views.
Dr Hughlings Jackson has written much in the present as well as in former communications of aphasia as indicating a lesion both of the faculty and expression of the internal and external organ of language. Many of his opinions are ingenious, and all curious: but it is conceived that he has altogether over- looked the consideration that the recognition of the laws and the practical use of language are purely mental acts; that they do not necessarily involve the use of articulate words; that in the uneducated deaf and dumb no articulate sounds are known, although the cerebral area and the organs of articulation are both present and healthy, so that it must be the nexus, what- ever that may be, which is at fault; that there must be many cerebral organs, if any, and only some of these injured in certain aphasics, who lose not their whole language, or difficult and polysyllabic words, but whole and distinct classes of words only, such as verbs, nouns, &c., or only one or more of several known languages; that in employing mentally the signs of any, even emotive mental states, there is no corresponding action of the muscles or other vocal organs, and it is matter for regret that he had had recourse to the solutions afforded by Fournie, who speaks of a nascent but unobvious movement of the organs of speech, and by Bain’s absurd and untenable proposition, tliat ” When we recall the impression of a word or a sentence, if we do not speak it out, we feel the twitter of the organs just about to come to that point.”
The author, although propounding dogmata many of which may be regarded as heretical, is no dogmatist. He introduces his opinions, even when he regards them as especially novel and important, sometimes with hesitation, sometimes as if they were provisional and temporary, always with modesty and for- bearance towards actual or supposed antagonists; and is worthy of all praise in urging the necessity for marking and measuring the precise situation of lesions in the attempt to localise mental or motor influences; while his instructions as to the course of observation (p. 22) to be pursued in reference to palsy and other nervous disorders, indeed the whole of the latter pages of the pamphlet, are worthy of consideration. But there are two grand, we would say vital, objections to the mode in which he lias developed his various convictions and hypotheses. First, wTe do not speak merely of the vice of style, of the lack of logical lucidity, involved parenthetical paragraphs, many of which are incomprehensible to minds of moderate capacity; but of the technical and still unrecognised terms employed, which at once obscure his meaning and the force of his argument. It may be that this metonomy may, in part, depend upon the poverty or inflexibility of our mother-tongue; but it is more palpably chargeable against obscurity of thought, crude notions, doubtful premises, disputable conclusions, and against that tendency which all innovators, perhaps all dis- coverers, have yielded to, of devising new words, or misapplying- old ones, in order to expiscate their own conceptions, rather than the qualities or entirety of the thing conceived. Has Science secured any gain by the introduction of ” discharging lesion or has she lost by associating a simple alteration of structure with an explosive shell, and the expulsion of an imaginary shot or shell from the brain ; or are our ideas enlarged when we are told that ” chorea and convulsions are discharges of cerebral cortex,” and that the ” causes of epilepsy are discharges from different brain-centres,” and that the havoc inflicted by palsy issues from a ” destroying lesion ?” That the illustration is not overdrawn, may be seen in the application of the specific terms ” abnormal” and ” morbid” to such discharges. Can we appreciate the distinction between a ” healthy and nervous discharge in con- vulsions, by the latter being more sudden, excessive, and brief; ” or can we fully realise that the ” spreading of spasm is due to different lesions in the grey matter exploded;” or that there was any justification for describing the progress of nervous diseases from the more simple to the complex, from the voluntary to the automatic functions, by the new term ” dissolu- tion,” in contradistinction to the now hackneyed ” evolution ?” Expressions such as the ” coarse, brutal development of func- tions of brain,” and a “coarse lesion as not being a neat experi- ment,” we attribute to the idiosyncrasy of the author ; while the inability to comprehend such profound truths as, ” Deeper in brain, further in mind, more complex arrangements of motor processes, reaching interrelation with complex motives,” and the ” substrata of consciousness, memory, &c.,” to our own. Secondly, the author, though manifesting considerable anxiety, knowing that he is dealing with sharp and dangerous instru- ments, to avoid the infliction of wounds upon the principles or even the prejudices of moderate men, and to repel charges of scepticism and materialism, appears on the threshold of what he believes to be a new revelation in somewhat suspicious company. Herbert Spencer, Tyndall, Eain, Lewis, represent a certain school of thought; and if Dr Hughlings Jackson does not doubt and disbelieve, he assuredly thinks, on many points, as tlie}r think. Although he distinctly disclaims all disposition to penetrate into the mode of connection between mind and matter, admitting only their parallelism, and although he quotes Tyndall’s platitude that we cannot reason out the simultaneous appearance of motor and mental acts ; yet he concurs with Lewis, that neural process and feeling are the same thing under different aspects, and many of his own propositions are susceptible of an interpreta- tion which may imply that these conditions differ not in nature, but as they are viewed from different standpoints in philosophy. Such are the following : ” Motion enters as an element, not into ideas, but into the anatomical substrata of ideas ” Sensations, as mental states, arise during energising of motor as well as sensory nerve processes,” thus concluding that when we see a rose as well as when we will to pluck it, or extend our hand to pluck it, there is movement in convolutions.
It is superfluous to carry this analysis further, and we are disposed to accept the explicit denial that his views of the consti- tution of mind are, as of the cerebrum cerebral, neutralising- the inferences which might be drawn from vague and circumlo- cutive expressions.
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