No. 3443.

AUGUST 24, 1889.

ABSTRACT OF THE

Address in Medicine,Delivered at the meeting of the British Medical

Association, Leeds,

BY J. HUGHLINGS JACKSON, M.D., F.R.S.

ON THE COMPARATIVE STUDY OF DISEASES OF THENERVOUS SYSTEM.

AFTER thanking the President and Council of theAssociation for the honour conferred upon him by theirrequest to deliver this address, the lecturer dwelt upon thenecessity of having generalisations and working hypothesesfor the classification and organisation into higher knowledgeof the multitudes of accumulated facts, and continued asfollows.We have, ready made for us, so to speak, the hypothesis

of evolution-one verified in numerous different cases.

Huxley writes: "The peculiar merit of our epoch is thatit has shown how these hypotheses [one of which is thedoctrine of evolution] connect a vast number of seeminglyindependent partial generalisations ; that it has given themthat precision of expression which is necessary for theirexact verification ; and that it has practically proved theirvalue as guides to the discovery of new truth." Theindirect value of the doctrine of evolution to clinicalmedicine is very great indeed, and before long it will bewithout doubt directly helpful. We should also attempt aparallel study of diseases, as they are dissolutions-that is,reversals of evolution. Precise generalisations of greatvalue would result from this method. The greatest meritof Gaskell’s work consists in his having set many thingslong ill-assorted in realistic order. By so doing he willhave put a stop to certain loose explanations in which thesympathetic figures. Generalisation, as here applied, is theclassification of things which are for the most part verydifferent by some fundamental peculiarity each of them has.I will give a series of illustrations of the method spoken of,Because it is one I follow largely in this address.

1. A patient of mine had lost one hand, but, as is mostoften the case, he had representing it a phantom hand ;this was always in such position as if encircling a vessel ;the member had been blown off when he was holding acylinder to be charged with an explosive.

2. An aphasic patient of mine frequently uttered, onbeing questioned, but with no relevance to anything goingon, "Come on," or come on to me."

" He was a signal-man, and had been taken aphasic and hemiplegic on therailway in front of his box ; the presumption is thathe was saying, or was about to say, those words whentaken ill.

3. An epileptic patient told me that his first fit occurredwhen he was a soldier, and at the very time he was

"numbering off"; after every subsequent fit, and beforeregaining consciousness, he used to count; this we observedwhen he was in hospital.

4. A woman I was asked to see in a surgical ward in theLondon Hospital, who had fractured her skull by a fallwhen laying down oil-cloth on a staircase, kept, duringpartial unconsciousness a few hours before death, manipu-lating the counterpane of her bed. We supposed this to bea sort of continuance of the action of laying down the oil-cloth ; the patient desisted, for a time at least, when thenurse assured her that "it was properly laid."The consideration of these illustrations, which appear in-

coherently grouped, is to make a basis for the discovery ofthe reason why there is a fixation of states, normallytemporary, upon the sudden occurrence of lesions of thenervous system; very different cases are chosen in order tomake the basis a broad one. The comparative study ofnervous diseases--the study of them as dissolutions-is aprocess of generalisation. The symptomatology of eachmust be regarded as the result of a flaw in an evolutionarywhole, and should take into account the evolution goingon in the undamaged remainder of the nervous system. Agreat part of the symptomatology of ocular paralysis is i

owing to over-activity of perfectly healthy nervous arrange- i

ments, and the same is true in a case of insanity, theerroneous projection and diplopia in the first, and theiilusions, delusions, and all other positive mental symptomsin the second, resulting from the activity of undamagedparts. (1) Evolution is a passage from the most to the leastorganised, high organisation meaning perfection of unionand certainty of action of nervous elements with oneanother. In this sense the highest cerebral centres are theleast organised (the "most lielpless centres"), althoughthey are the most complex ; whereas the lowest centres arethe most organised, although the least complex. In otherwords, (2) the evolutionary ascent is from the least to themost modifiable. If the highest entres were not modifiable,we should be very simple machines; we should make nonew acquirements. If the lowest (" vital ") centres were tobecome as modifiable as the highest are, life would cease.It is only another aspect of this to say (3) that the passageis from the most automatic to the most voluntary; equi-valently it is (4) from structures inherited most nearly per-fected, such as the cardiac centies in the medulla, to thoseof the highest nervous arrangements of the highest centres,which are only incipient nervous structures, and which areevolving during the latest new mental states. (5) The processof evolution is from the simple to the complex; (6) from thegeneral to the special. Reversals of evolution are effectedby pathological processes, and are called dissolutions.They are reductions from the least organised &c. towardsthe most organised &c. In regard to the periphery,in most cases of progressive muscular atrophy, themuscles first morbidly affected are the small musclesof the hand, and in most cases of Duchenne’s bulbarparalysis the tongue is first invaded. In both cases

the special parts fail first. Going higher, it is plain thathemiplegia from disease in the mid-cerebral region is afailure in the order from "most voluntary" towards mostautomatic. Chorea and paralysis agitans illustrate dissolu-tion in the same manner as hemiplegia, and the variousphenomena of aphasia illustrate this still better. Dr.Donald MacAlister, in his admirable Croonian Lectures,pointed out that the febrile process exemplifies dissolution."In the ascending scale of evolution we seem to rise fromthe thermolytic to the thermogenic, and thence to thethermotaxic nervous system." Fever is a process of dis-solution, and recovering from it one of re-evolution.Probably all cases of insanity illustrate dissolution. "Thatgeneral paralysis," Dr. Savage writes, "affects first thehighest intellectual and !uotor acquirements is undoubted.Both Dr. Maudsley and I have independently taughtthat in this progressive degeneration the last andhighest acquirements’ fail first."’ An entirely parallelstate is seen in the symptomatology of drunkenness:the muscles of the tongue, the eyes, the face, and the limbsbecome successivelv unmanageable; and under the samecircumstances muscles which have a double office, such asthose of the chest, lose their voluntary and retain theirinvoluntary motions; the force of the arms is gone longbefore the action of breathing is affected. We see, notdissolution, but evolution, illustrated by certain surgicalcases, by the order of persistence of spectral representationsof parts lost by amputation. Weir Mitchell writes: "Thelimb is rarely felt as a whole; nearly always the foot or thehand is the part more distinctly recognised, and on carefulquestioning we learn that the fingers and toes are readilyperceived; next to these the thumb; then more rarely theankle or wrist; and still less frequently the elbow andknee. Very often some fingers are best felt, especially theforefinger." This, the order in which the lost parts remainmost vividly represented in consciousness, is almost exactlythe order in which the parts physical do fail in dissolutionof the nervous system. Speaking generally, the hemiplegicman is reduced to a more automatic condition of move-ment, the aphasic to a more automatic condition oflanguage, and the insane man to a more automatic con-dition of mind.

Dissolution is exemplified in each of the following verydifferent symptoms. 1. Most epileptiform seizures commencein the thumb or index finger, or in both; thee digits arethe most special parts of the body. 2. The words most oftenleft to an aphasic, who is for the rest entirely speechless, areCc yes’ or "no," or both ; these " words," as I called them,are the most general of all propositions. 3. The aphasicmay be unable to put out his tongue when told, although hemoves it well in other ways : loss of the "most voluntary"

tr

356

movement, with persistence of the more automatic move-ments of that organ. 4. In what is called word-blindnessthere is inability to recognise the latest learned, and veryarbitrary " objects," letters, and words, whilst the reco-

gnition of objects, properly so-called, is unimpaired or com-paratively so. 5. In early stages of atrophy of the brain-say in that occurring so often in hemiplegia in men pastmiddle age-there is defect of memory for recent events,with seemingly good remembrance of long past circumstances,and there is at the same time loss or defect of the " finest " iand latest acquired emotions, with obtrusion of the coarserand earlier acquired.As to the evolutionist’s measure of mind, a scientific

standard ignores superior and inferior, as these terms areordinarily used with regard to men’s minds. Higher racesof men and adults have the latest acquired faculties, andthese, according to Spencer, are, intellectually, the powerof abstract reasoning, and, emotionally, the sentiment ofjustice. In the cases of atrophy of the brain recentlyinstanced, there first occurs defect of the two "latest"faculties I mentioned; the patient easily becomes confusedby consideration of things of a little complexity, and ofwhich the elements are not before him, and is often peevishand selfish. It may be said that the symptoms from morbidchanges in the cerebellum do not accord with statementsmade as to the process of dissolution. I believe that all theskeletal muscles are represented in the cerebrum in one setof movements, and that all of them are represented inthe cerebellum in another set of movements. In rough andonly partial statement, the order of representation in thecerebrum is of movements of the arm, leg, and spine. Thisagrees with a popular doctrine, for the order is that of thedegree in which the three parts of the body are " under thecommand of the will." The order of representation in thecerebellum is of movements of the spine, leg, and arm.This accords with the current doctrine that the cerebellumcoordinates movements of locomotion. The arm then isthe most special part in the cerebral series, and fails first indisease of the brain proper; and the back is the mostspecial part in the cerebellar series, and fails first in dis-ease of the cerebellum.By the aid of the doctrine of evolution we shall discover

a harmony or rational parallelism between (1) psychology,(2) the anatomy and physiology of the nervous system, and(3) that important part of clinical medicine which dealswith diseases of this system. It will help us towards acomparative study of all diseases of the nervous system, andparticularly of insanity. The doctrine of evolution impliesthat the whole nervous system has a sensori-motor constitu-tion. I extend this to the highest cerebral centres, which

Tepresent parts of the body as certainly as the lumbarenlargement does; they are evolved out of lower centres,which everybody admits do represent parts of the body.No one denies that the highest centres contain sensoryelements; no one denies that very many, if not all, parts ofthe body are represented sensorily in the " organ of mind."But there seems to be great objection to their representa-tion motorily in that organ. The praefrontal lobes are saidto be the " mental centres." That they are a great divisionof these I admit, but that they are motor also is shown bythe appearance of descending degeneration as far as themedulla after their ablation in monkeys.

I will here state in outline what I believe to be thehierarchy of the motor centres. 1. The anterior spinal hornsand their homologues higher up (nuclei of motor cranialnerves) are the lowest motor centres (both of the cerebraland cerebellar systems). These lowest motor centres, withthe corresponding sensory centres, make up the lowest levelof evolution of the central nervous system. 2. The convo-lutions of the Rolandic region are the middle motor centresof the cerebral system. With the corresponding sensorycentres, they make up the second or middle level of thecentral nervous system. 3. The prsefrontal lobes are thehighest motor centres of the cerebral system. With the cor-responding sensory centres, they make up the third or

highest level of the central nervous system-that is, the" organ of mind." Movements rather than muscles are re-

presented in the central nervous system. The movementseffected by, say, thirty muscles of the hand are representedin the nervous centres in thousands of different combina-tions ; just as so many chords, musical expressions, and tunescan be made out of a few notes.

I now speak of the representation of the muscles of thehand in the three orders of motor centres just spoken of:

1. In some lowest motor centres (anterior horns), which areevolved out of the muscles of the hand, the muscles are re-presented in numerous different combinations, as simple andvery general movements. 2. In the middle motor centres(Rolandic region) which are evolved out of the lowest motorcentres, the same muscles are represented (re-represented) instill more numerous different combinations, as complex andspecial movements. 3. In the highest motor centres (pne-frontal lobes), which are evolved out of the middle motorcentres, the same muscles are represented (re-re-represented)in innumerable different combinations, as most complex andspecial movements-the last representative of the "finest"movements of the hands in the anatomical substrata oftactual ideas and of other mental states.The highest centres ("organ of mind ") have no other

function than that of representing parts of the body.Bearing in mind the subordinate centres, they may be saidto represent parts of the body triply indirectly. Functionis a physiological term, and not applicable to states ofconsciousness, such as attend functioning of the highestcerebral centres. We can only affirm concomitance, andthe association is as yet inexplicable. According to thelate Professor Clifford, between the physical facts and themental facts there is a parallelism, but no interference ofone with the other. It is not the mind, but the physicalbasis of mind, which is a product of evolution, and thesensori-motor hypothesis is not put forward to attempt toexplain psychical by anatomico - physiological states. Icontend that the highest centres represent all parts of thebody supplied by nerves ; not only sensory parts, but limbsand internal viscera. The highest centres are centres of uni-versal representation or coordination. Dr. Mercier, dealingwith coma, writes : " Thus we arrive at this most importantconclusion-that the highest nervous processes, which formthe substrata of the most elaborate mental operations, repre-sent at the same time, not only the most elaborate forms ofconduct and muscular movements, but also every part of theorganisrn" (italics in original) in some degree. Ribot,writingon Personality, says: "Nous pourrons dire que le couchecorticale represente toutes les formes de 1’activite nerveuse-viscerale, musculaire, tactile, visuelle, significatrice." Thelowest level (pons, medulla, and cord) represents all partsof the body; certainly motor effects in nearly all parts ofthe body are produced by discharges of the " motor region."I am only going a step further when I suggest that thehighest level is also universally representing. A higherlevel of evolution is, so to put it, the lower 11 raised to ahigher power." The phenomena of an ordinary epilepticfit seem to me to accord with the hypothesis of sensori-motor constitution and universality of representation.Cessation of consciousness results from a discharge begin-ning in some part of the physical basis of consciousness.Effects which are motor, or their equivalent, are seen in allparts of the body. In slight fits the effects are widely dis-tributed, including pallor of face, increase of saliva, arrestof respiration, and emission of urine. The epileptic dischargediffers from an ordinary one in being sudden, excessive, andrapid, and also in starting in some small part of the highestcentres (a discharging lesion "or "physiological fulminate").Artificially induced discharges in the Rolandic region pro-duce effects in all parts of the body, including the viscera;for if curara be given to a dog, and the sigmoid oyrusfaradised, the fit is limited to the organic parts, and includesincreased flow of bile, paling of the kidneys, and contractionof the spleen. That universal effects are so produced givessome countenance to the supposition that the anterior

highest motor centres are also universally representing. Tostate this in another way : Whilst a man is having statesof consciousness (willing, remembering, reasoning, andfeeling), there occur correlatively slight discharges ofnervous arrangements of his highest centres repre-senting the whole of his body. Here is best seen theharmony of psychology with the anatomy and physio-logy of the nervous system, and here lies the basis ofa comparative study of insanity (diseases of the highestcentres) with diseases of the lower centres. When weexplore an object the skin of our fingers and the muscles ofour hands are engaged. During the actual explorationthere is a vivid mental state ; in thinking of it when absentthere is a faint mental state. In both cases there is sensori-motor action, in both the same nervous arrangements of thehighest centres. If the discharge were sudden, excessive,and rapid, there would be a miniature epileptic fit, withtingling referred to the fingers, and convulsion of the hand.

357

Accepting, provisionally, the conclusion that the ana-tomical substrata of will, memory, reason, and emotionrepresent together all parts of the body, sensorily andmotorily, how is it that such apparently different pheno-mena as convulsion, with cessation of consciousness and

insanity, result from morbid affection of the " organ ofmind "? Often enough there is the sequence of an epilepticconvulsion with loss of consciousness and then post-epilepticmania. Moreover, I believe that paralysis also results fromnegative states of these centres; it exists in temporarypost-epileptic insanities-indeed, in every case of insanity.According to the severity of the paroxysm, there is eithermania or coma, which is acute temporary dementia rapidlyproduced. The negative affection of consciousness in thecomatose patient implies a correlative negative state ofmore or less of his highest centres, which causes paralysis.That there is some universal paralysis after a severe epilepticfit accords with the hypothesis of universal representationby the highest centres, and is in harmony with the univer-sality of the convulsion in the prior paroxysm. That thereis paralysis is indicated by lateral deviation of the eyes andalteration of the deep reflexes observed after such seizures.The loss of power in post-epileptic coma is probably dis-trihuted over the highest, middle, and lowest centres.From the conclusion about post-epileptic coma, we make

the hypothesis that there is a widespread or universalparalysis in all cases of insanity, corresponding with theuniversality of representation by the highest centres, whichare here certainly diseased. In all cases of insanity boththe mental and physical conditions are duplex-positiveand negative. The defect of consciousness and the positivemental symptoms varv inversely, and either may attractexclusive attention. But surely these positive symptomsof themselves imply the coexisting negative states of somenon-recognition and some non-reasoning-that is, theyreally imply some coexisting defect of consciousness. Re-garding the physical condition of the highest centres, thenegative affection implies some temporary or actual loss offunction, implying paralysis ; the positive, some functionover-active from loss of control or counterpoise. Thedelusions of insanity signify evolution going on in theremains of a mutilated nervous system, as certainly as thebeliefs of sanity signify evolution going on in an entirenervous system. In post epileptic mania, the positivesymptoms are due to a great hyper-physiological activityof the healthy third layer, which are no longer controlled bythe highest two layers of the highest centres. When arabbit’scerebrum is cut out the animal is demented. But movementsof every part of its body can be evoked by appropriate incita-tions. Nevertheless, I declare that the animal is paralysed.It retains all simple movements represented on the lowestlevel of evolution, which is pretty much all that is left ofits cerebral series. But it has lost all the more complexmovements, those which we should distinguish as thephysical aspect of conduct, and is therefore universallyparalysed. So the incoordination which results from atumour of the middle lobe of the cerebellum is referable,not to the direct influence of the lesion, but to the over-activity of perfectly healthy nervous arrangements, whichare doing more than their normal share of work, owing toloss of some movements of the spinal muscles. In com-paring such a case with one of hemiplegia, the comparisonis not one of incoordination with hemiplegia, but of lossof movements of the spinal muscles with loss of movementsof the limbs. I submit that the formula describing allincoordinations with negative lesions of the nervous centresis that there is, negatively, loss of some movements,paralysis (this alone being the result of pathological change),with, positively, forcing of some other movements of thesame muscle. In saying this, the assertion that much of thesymptomatologies of nervous diseases is owing to activitiesor over-activities of healthy nervous elements is implicitlyreiterated. I believe that in what is commonly calledtremor in a case of disseminated sclerosis-say of an arm--there is paralysis in the sense of loss of some movementsof the limb; the tremor itself is owing to the fact that theexcursions of the limb have to be effected by fewer, andpresumably less fit, movements than normal. Observe,there is loss of some and retention of other movements ofthe same muscles. The movements by which the limbcarries, although erratically, a cup to the mouth are notblameworthy; they are the best in the evil circumstances-the next best to the normal; they are produced, I suggest,by discharge of healthy nervous arrangements. When a man

has paralysis of the extensors of the forearm his grasp isweak and the hand moves clumsily in all its uses. But noone thinks of blaming the flexors for the weak grasp and forthe clumsy operations of the limb ; the flexors are actingfaithfully; what they do is badly done because the ex-tensors will not co-operate. So I suggest that, in the kindof tremor spoken of, the fault is that, certain movementsbeing lost, they no longer co-operate with others which,being unaided, move the limb erratically ; the real fault,what the pathological change causes, is paralysis. That apatch of sclerosis, if it be an absence of proper nervouselements, can cause any movements, good or bad, is animpossible thing ; the tremor has, however, been ascribedto imperfect function of intact axis cylinders in the partssclerosed.

I have long held that the lesion in cases of aphasia pro-duces paralysis in the sense of loss of complex &c. movementsof the articulatory muscles. It may, however, be urged thatthe articulatory muscles move well ; so they do in simpleoperations, but they never move so as to make articulations(syllables). The experiments of Semon and Horsley demon-strate, in one case at least, that there may be loss of somemovements of a muscular region, with persistence of somany other movements of that region, that no disability inthe working of the muscles is discoverable. (These experi-ments are a strong confirmation of Broadbent’s well-knownhypothesis, for one case at least.) In cases of perniciousdiabetes the lesion is supposed to be of a certain part of thegreat vaso-motor centre, the disease producing nothing butparalysis of the hepatic arterioles. As a result of localparalysis from lesion of part of the spinal system, it is com-parable to ordinary progressive muscular atrophy or anteriorpolio-myelitis. I suggest that the xerostomia described byHutchinsonand Haddenisalsoaparalysis, owing to anegativelesion of the centres for the motor nerves of the salivary andother oralglands. The essential thing, that which disease, inthe strict sense of pathological change, produces in cases ofinsanity, "disorders of co6rdinttion," with negative lesions,tremor, aphasia, pernicious diabetes, and xerostomia, is

paralysis. I submit the hypothesis that (1) progressivemuscular atrophy, (2) paralysis agitans, and (3) generalparalysis are homologous diseases. The comparison andcontrast is not of wasting of muscles, tremor, and a

negative psychical defect; but there is loss respectivelyof (1) simplest, (2) more complex, and (3) most complexmovements of the hands. The comparison is of threecases of paralysis. The lesion is supposed to be wastingof cells, in the order from smallest towards largest,of lowest, middle, and highest motor centres respectively.1. In progressive muscular atrophy there is loss of simplestmovements of hands, of those represented in the lowestmotor centres. The muscles are cut off from the influenceof the central nervous system and waste. Were there not,however, retention of more complex middle and highestcentres, the patient could neither think nor dream of movingthe part, and would have no physical basis for tactual ideas.2. In paralysis agitans there is, negatively, loss of complex(middle) movements of the hand, and at the same time,super-positively, over-development of simplest movements.3. In general paralysis there is loss of some of the most com-plex (" finest ") movements of the hands, those representedin the highest motor centres, of those entering intothe physical bases of tactual ideas, and of other mentalstates. Here there is retention of less complex (middle),and of simplest (lowest) movements. The negativepsychical defect in general paralysis is wider than thatanswering to loss of motor elements in the highest centresrepresenting the hand. Yet, if Spencer be right in sayingthat all other ideas have to be translated into tactual ideas,to lose these is to become imbecile. I ask you to bear inmind the suggestion that the positive mental symptomscorrespond to activities of healthy nervous arrangements.If so, we have nothing to do with them at the time we aredealing with the effects of pathological processes. Mostmentation is carried on in visual and tactual ideas, and byaid of words. To have negative affection of consciousnessis, therefore, to have especially loss of these three ; andthus it implies that there is correlatively a negative stateof their sensori-motor bases. In general paralysis, the lesion,if of the highest motor centres, is of the motor elements inthose sensori-motor nervous arrangements-is loss of more orfewer of the most complex ocular, manual, and articulatorymovements ; the lesion, therefore, produces paralysis in theense of loss of the "finest" movements of the three parts.