Mind, Brain and Adaptation in the Nineteenth Century: Cerebral Localization and Its Biological Context from Gall to Ferrier
by
Robert M. Young
[ Contents | Preface | Introduction | Chapter: | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | Bibliography ]
4
PIERRE PAUL BROCA AND THE SEAT OF
THE FACULTY OF ARTICULATE LANGUAGE
Problems as presented and explanations as offered in scientific documents of the past are more often than not made intelligible to us only by asking what their author thought he was doing: what he saw as a problem, how he conceived the method of finding a solution, what modes of explanation he regarded as satisfactory.
A. C. Crombie, 1963.
It is ironic that the experimental psychophysiology which stood diametrically opposed to Gall's conception of the functions of the brain and which reverted to the psychological tradition which he opposed, should have derived its belief in cerebral localization from phrenology. To assert baldly that the view of cerebral localization which Jackson and Ferrier used was derived from phrenology is to speak very loosely and to convey a false impression. Such an assertion is not a simple truth, but a complex one. Ferrier used three sources of the concept of cerebral localization: Broca, Fritsch and Hitzig, and Hughlings Jackson. Ferrier was not faithful to the precise conceptions of any of them. The views of localization employed by two of them grew historically out of phrenology-those of Broca and Jackson.
Broca's localization of a centre for 'the faculty of articulate language' was the first localization of a function in the hemisphere which met with general acceptance from orthodox scientists. Consequently, Broca is usually credited with priority in initiating the modern doctrine of cerebral localization.[1] This citation has appeared with such regularity that this fact alone gains for it a species of historical truth. However, if one begins to examine his claim to priority, it is difficult to establish with any degree of certainty. His work is part of a continuous consideration of aphasia and cerebral localization that stems directly from Gall and was a live issue throughout the intervening decades. Neither the conception of a faculty of articulate language nor its localization in the frontal lobes was novel. It might be argued that Broca was the first to confirm this localization and to clarify it with clear-cut pathological evidence, but the fact is that the quality of the evidence of his original case was very dubious indeed. What Broca seems to have contributed
1 E.g., Herrick, 2nd ed., 1925, p. 19; Walker, 1957, p. 104; Boring, 1950, p. 70.
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was a demonstration of this localization at a time when the scientific community was prepared to take the issue seriously. Those who had advocated cerebral localization of speech functions prior to Broca were so tainted by their connections with phrenology that the debate on the issue had the character of a local (and partly political)[1] squabble in Parisian medical circles. It is not clear how this occurred, but somehow Broca's confirmation of a finding that had been made and contested repeatedly for thirty-five years elevated it from the local level to that of an important finding which was considered seriously on an international scale. Broca was certainly no more eminent than Bouillaud, who had been advocating the view since 1825. Without further investigation, it is not possible to explain the significance attributed to Broca's advocacy of cerebral localization. In any case, his main contribution seems to have been a propaganda victory rather than an original discovery.
A brief discussion of the background of his 'discovery' and of his first case should show the relation of his method and conceptions to those of phrenology, the difficulties involved in the clinico-pathological method, and the relations between these and the work of the experimental psychophysiologists which constitutes the main line of investigation under review.
Observations on diseases affecting speech were made as early as the Hippocratic corpus (c. 400 BC.), and more or less identifiable descriptions of speech pathology are scattered through the history of medicine since then.[2] Accurate descriptions of motor aphasia were made at least as early as 1673 (Johann Schmidt) and again in 1683 (Peter Rommel).[3] However, no important ideas about localization of the lesion had been advanced prior to 1800,[4] and Gall is usually credited with 'the first complete description of aphasia due to a wound of the brain'.[5] The case on which this claim rests was that of a young man brought to Gall by Baron Larrey (another physician) who had been wounded by the point of a foil which entered at 'the middle part of the left canine region, near the nostril' and penetrated 'in a vertical direction and a little oblique from before backward, to the depth of five or six lines in the internal posterior part of the anterior left lobe of the brain, in such
1 See Temkin, 1947, p. 306, and below pp. 145-6.
2 Benton and Joynt, 1960.
3 Ibid., pp. 209-10.
4 Ibid., p. 220.
5 Head, 1926, 1, 9. The case Riese reports from Goëthe (Riese, 1947, pp. 322-3) neither was the first (see Benton and Joynt, 1960, p. 205), nor was the lesion traumatic. Both it and that reported by Pinel were due to apoplexy. Riese's revelation (1947, p. 323) that Pinel described a (non-traumatic) case prior to Gall would not have surprised Gall, since he quoted it. (1835, V, 22-3.)
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a manner to approach the anterior part of the mesolobe'.[l] The clinical description of his symptoms is excellent. The patient's 'memory of names' was wholly extinguished. For example, though he recognized Baron Larrey, he 'could not recall his name, and always designated him as Mr Such-a-one'.[2]
Although this claim for Gall is legitimate, it is less interesting than its context. It should be recalled that the 'Faculty of attending to and distinguishing Words; Recollection of Words, or Verbal Memory', was the first of Gall's discoveries. It was this ability which he correlated with 'large, flaring eyes' in those of his classmates who were better than he at learning by heart.[3] He had made this correlation long before he thought of relating external signs to the underlying brain. 'It was this which gave the first impulse to my researches, and which was the occasion of all my discoveries.'[4] Other external signs were sought by analogy from this one. Later, after he based his formerly physiognomical doctrine on the brain, he inferred that large, prominent eyes were the result of the size of the 'organ of verbal memory, that cerebral part which rests on the posterior half of the roof of the orbit'.[5] The form of the orbit was changed 'according as all the cerebral parts placed on the roof. . . .' When they are highly developed, 'the eyeballs are pushed forward, whence result large prominent eyes'.[6]
A false impression is conveyed by taking Gall's case of a localized lesion out of context. His method of discovering it, and his reasoning about the seat of the faculty give some indication of the subordinate role of cases of localized lesions in his investigations. In describing his methods, he explicitly said that inspection of brains and 'accidental mutilations' (pathological lesions) played a subordinate role in confirming localizations which he had discovered by his cranioscopic methods.[7] Correlation of cerebral injuries with disturbance of a given function consituted 'a new proof' only 'after the seat of an organ has been discovered by other means, and this discovery has been sufficiently proved. . . .'[8] In writing about loss of speech, Gall gave no more weight to the account of the sword injury than he did to the following 'evidence' from another patient: 'In his embarrassment, he points with his finger to the lower part of his forehead; he manifests impatience, and indicates by his gestures, that it is from that point, that his inability to speak comes'.[9]
1 Gall, 1835, V, 16.
2 Ibid., V, 18.
3 Ibid., V, 7-8; Gall, 1835, I, 58-9.
4 Call, 1835, V, 8.
5 Ibid., V, 11.
6 Ibid., V, 4.
7 Gall, 1835, III, 120, 128.
8 Ibid., III, 128-9.
9 Gall, 1835, V, 23.
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Gall's evidence for localization of the seat of the faculty of verbal memory was no less confused than his conception of the faculty itself. While acknowledging that he did provide early descriptions of the symptoms of motor aphasia, one should realize that his conception of the faculty was a hodgepodge when considered from a modern point of view. He did separate the patient's apparent ability to understand questions from his ability to speak voluntarily. He also noted that ability to speak could be impaired when the ability to move the tongue and pronounce isolated words was intact. Finally, he observed that the ability to express ideas by gestures and to identify objects could remain intact while various modes of formal expression, speaking, and writing are impaired.[l] However, his first descriptions involved ability to learn school lessons easily and recite them well. Thus the functions involved were not solely those of forming propositions and articulating them. The responsible faculty also accounted for the desire to make collections, study meticulously, read, and for various aspects of learning ability or intelligence. The phenomena of verbal expression were, therefore, not clearly separated from those of learning, retention, and recall. It was from a mixture of accurate description, confused methods, and rank nonsense that the idea took root that the memory for words was situated in the frontal lobes.[2]
The link between Gall and Broca is through Jean Baptiste Bouillaud (1796-1881).[3] Bouillaud received part of his clinical training from Gall, and he was a founding member of the Société Phrénologique which was organized in Paris three years after Gall died.[4] In 1825, he published a paper in which he argued on the basis of clinical evidence that loss of speech corresponds to a lesion of the anterior lobes of the brain, and that his findings confirmed Gall's opinion on the seat of the organ of articulate language. He opposed Flourens' view that the brain exerted no immediate and direct influence on the phenomena of speech and argued on the basis of cases of his own and from the literature that the brain plays an essential role in many movements, and that there were special organs in the brain for definite movements. 'In particular, the movements of the organs of speech are regulated by a special cerebral centre, distinct and independent. This is situated in the anterior
1 Gall, 1835, V, 22-4.
2 Head, 1926, I, 9.
3 I have not read Bouillaud's papers, since his role in the history of cerebral localization is that of a link, not a direct contributor to the development of concepts or new findings. The comments on his work in the text are drawn from the following sources: Head, 1926, 1; Wilks, 1879; Bastian, 1880; Ferrier, 1890; Walker, 1957; Joynt, 1961; Jefferson, 1960; Ackerknecht and Vallois, 1956; Ombredane, 1951. Most of the discussion follows Head closely (1926, I, 13-20).
4 Ackerknecht and Vallois, 1956, p. 34.
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lobes of the brain. Loss of speech depends sometimes on lack of memory for words, sometimes on want of the muscular movements of which speech is composed.[l]
His investigations involved an important change of methodological emphasis from the work of Gall. The correlations which he made were between clinical symptoms and brain lesions. The method of clinicopathological correlation replaced that of correlating striking behaviours with cranial prominences and occasionally checking these against the brain. Bouillaud insisted that observation of the brain was essential in all cases. He arrived at his support of Gall by comparing the results of pathological studies with the opinions of phrenologists on the general issue of localization and the particular issue of a cerebral organ for articulate language. He believed that Gall ' "had announced rather than demonstrated" the fact'.[2] He was at once more precise and more vague than Gall. He was concerned with speech itself and not with the other aspects of Gall's faculty of verbal memory. However, his localization was less clearly defined than Gall's, and he claimed only that its seat lay in the frontal lobes.
He continued to present pathological cases in support of cerebral localization involving paralyses, loss of sensation and especially speech. He published a treatise in the same year as his original paper which contained 114 observations of disease of the frontal lobes accompanied by loss or defect of speech.[3] His views on aphasia were applications of a general principle of cerebral localization of muscular movements.
It is evident that the movements of the organs of speech must have a special centre in the brain, because speech can be completely lost in individuals who present no other signs of paralysis, whilst on the contrary other patients have the free use of speech coincident with paralysis of the limbs. But it is not sufficient to know that there exists in the brain a particular centre destined to produce and to co-ordinate the marvellous movements by which man communicates his thoughts and feelings, but it is above all important to determine the exact situation of this co-ordinating centre. From the observations (cases) I have collected, and from the large number I have read in the literature, I believe I am justified in advancing the view that the principal lawgiver of speech is to be found in the anterior lobes of the brain.[4]
He distinguishes clearly between the two classes of loss of speech which Gall had noted but had not emphasized. 'It is important to distinguish
1 Quoted in Head, 1926, I, 13-14.
2 Quoted in Jefferson, 1960, p. 117.
3 Bastian, 1880, p. 674.
4 Quoted in Head, 1926, 1, p. 15.
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the two causes which may be followed by loss of speech, each one in its own manner; one by destroying the organ for the memory of words, the other by alteration of the nervous principle which presides over the movements of speech.'[l]
Bouillaud kept cerebral localization a live issue in the ensuing years. His views were vigorously opposed, but his work gained him the place of a popular professor of medicine at La Charité, Paris. He defended his position in 1839, in a lecture to the Académie de Médicine, in which he defined the relation of his views to those of Gall. Gall had considered the 'sense of words' from an intellectual aspect, while Bouillaud was more concerned with its mechanism. 'I wish to apply to the brain, considered as agent or principle of coordinated movements, that system of plurality which Gall invented for the same organ in as far as it is the instrument of intellectual and moral phenomena.'[2] He proposed a view of the mechanism of speech production and reaffirmed his belief in its localization in the frontal lobes. His paper led to a lengthy discussion of confirmatory and contradictory cases. His opponents 'were obsessed by the bogey of phrenology, whilst Bouillaud failed to explain why speech was sometimes gravely affected although the lesion was not situated in the frontal lobes'.[3] A paper read to the Académie de Médicine on localization in 1848 led Bouillaud to open another fulldress debate on the subject, which covered the old ground yet again. In the heat of the discussion he offered a prize of 500 francs to anyone who could produce a case of severe lesion of the frontal lobes without speech disturbance.
By 1861, Bouillaud was Doyen of the Faculty, Membre de I'Institut, and head of La Charité. Once again the issue of cerebral localization was being hotly debated, but the conduct of the debate had passed into the hands of the next generation. Broca was the secretary of the Société d'Anthropologie, which he had founded only months before. In February, 1861, a primitive human skull was presented, and debate followed on the significance of the volume of the brain. The issue was immediately expanded from the value of volume or form in determining the cultural level of a brain, to include the related issue of whether the brain functions as a whole or is composed of more or less independent organs or centres. Gratiolet, who presented the original skull, said, 'In a general manner I agree with M. Flourens that the intelligence is one, that the brain is one, that it acts above all as a whole; but this does not exclude the idea that certain faculties of the mind stand in special
1 Quoted in Head, 1926, I, 16.
2 Ibid, I, 16-17.
3 Ibid., I, 17.
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relation, although not exclusively, with certain cerebral regions'.[l] Ernst Auburtin, Bouillaud's pupil and son-in-law, rejected global measurements and unequivocally argued the case for cerebral localization. Broca, who had not discussed localization in the first debate, reopened the issue in March. He had high praise for Gall's anatomical work and for the principle of cerebral localization 'which has been, one may say, the point of departure for all the discoveries of our century on the physiology of the brain'. His advocacy of Gall's principles was carefully distinguished from their phrenological applications. 'I, for my part, believe in the principle of localization,' he said, and supported his belief with facts from embryology and anatomy.[2] Auburtin opened the sitting of 4 April, with case reports drawn in part from Bouillaud's writings, and upheld the value of pathological observations against those of physiological experiment. The clinicians were not only following Gall's principles in opposition to those of Flourens, but also upheld the value of a modified form of his naturalistic approach and correlative method. Since the first empirical demonstration of the principle of cerebral localization followed from these discussions, it should be noted that it came from the examination of an 'experiment of nature'. It was not until nine years later that cortical localization was demonstrated by the experimental method, by direct intervention into nature and the production of effects.
More particularly, Auburtin followed Bouillaud in upholding the association of speech with the frontal lobes. In a grand gesture reminiscent of his father-in-law's prize offer, he promised to abandon his belief in cerebral localization if anyone could produce a case of loss of speech without a lesion in the anterior lobes of the brain. Conversely, Auburtin argued that the localization of a single faculty would suffice to establish the truth of the principle of cerebral localization.[3] It was in this highly charged atmosphere that the patient 'Tan' (whose real name, Leborgne, has been almost forgotten because of the characteristic and symptomatic utterance that became his nickname) was proposed by Broca as a test case and accepted by Auburtin.[4] The patient died within a week of admission to Broca's surgical service with diffused gangrenous cellulitis of the left leg. He had lost his speech 21 years before and had been a patient at the Bicêtre since then. When Broca demonstrated the brain to the Société d'Anthropologic the next day he offered
1 Quoted in Head, 1926, I, 18.
2 Ibid. Cf. Broca, 1861, pp. 56-7.
3 Broca, 1861, p. 55.
4 Ibid., p. 56.
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his observations in support of the views of Bouillaud and Auburtin. However, the opponents localization were not immediately aroused, and Broca himself was agnostic about particular localizations in his closing remarks. It was Broca's complete account of this case to the Société Anatomique de Paris four months later that brought the debate to a climax.[1]
There are two important aspects of Broca's presentation in addition to the evidence he gives: his conception of method and his view of the functions which are to be localized.
His methodological observations involve the final and complete rejection of cranioscopy in localizing research. He notes that 'the phrenological school placed the seat of the faculty of language in the anterior part of the brain. in one of the convolutions which rest on the orbital roof'.[2] Bouillard's change in method was a fundamental advance. The phrenological localization of language,
would doubtless have disappeared with the rest of the system if M. Bouillaud had not saved it from shipwreck by making important modifications and by surrounding it by a series of proofs, mostly taken from pathology. Without considering the language as a simple faculty depending on only one cerebral organ and without trying to circumscribe within a few millimetres the place of this organ, as did the school of Gall, the professor has been led by the analysis of a large number of clinical facts, followed by autopsies, to state that certain lesions of the hemispheres abolish speech without destroying intelligence and that these lesions are always in the anterior lobes of the brain.[3]
Previous observations using the pathological method had not been incompatible with those reached by cranioscopy, but
it is enough to compare out observation with the preceding ones, to dismiss the idea that the faculty of articulate language resides in a circumscribed fixed point situated under a certain elevation of the skull. The lesions of aphemia have been found mist often in the most anterior part of the frontal lobe, not far from the eyebrow and above the orbital roof, whereas in my patient they were much further back, much nearer to the coronal suture than the superciliary arch. This difference in the localization is incompatible with the system of bumps.[4]
Broca recalled that the phrenologists had neglected the study of the cerebral convolutions 'far too much'. 'One allowed oneself to be
1 The original publication was 'Remarques sur le siège de la faculté du language articulé; suivies d'une observation d'aphémie, and it appeared in Bull. Soc. Anat., Paris. 6, 330-57, 1861. All quotations are taken from the translation in von Bonin, 1960, and page references are to it.
2 Broca, 1861, p. 49
3 Ibid., pp. 49-50
8 Ibid., p. 72.
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dominated by the old prejudice that the cerebral convolutions are in no way fixed, that they are simply pleats made by chance, comparable to the disorderly flexions of the intestinal loops'.[l] Broca pointed out that the fundamental convolutions were constant and that it would not be possible to attain an understanding of the limits within which the principle of cerebral localization could be applied until studies were made much more precise. Bouillaud had advanced methodology by insisting on pathological observations. Many more of these were needed to finally establish the principle of localization. But more was required than pathological observation and specification of only the area of the lesion or its distance from familiar landmarks on the brain's surface. 'We have to investigate not only in what parts of the brain are situated the regions of aphemia, but we also have to designate by their name and by their rank the diseased convolutions and the degree of alterations of each of them. So far one has not proceeded in that way.'[2] Broca followed his own advice and the further injunction that 'if the lesion is very large, to try to determine as much as possible by anatomical methods the point or rather the convolution where the disease seems to have started'.[3] It will become clear when the work of Fritsch and Hitzig and Ferrier is discussed that standard cerebral nomenclature became an increasingly important aspect of cerebral research.
Although Broca's observations were made in favour of a more precise version of Bouillaud's view of the seat of the faculty of language,[4] he differed radically from Bouillaud's conception of that faculty. (Bouillaud was apparently not troubled by this difference and accepted Broca's work as confirming his own.)[5] Broca's discussion reflects the prevailing confusion about the role of the hemispheres in muscular motion. When he describes the impairment of speech involved in the aphemia,[6] he is sympathetic to Bouillaud's view.
What they lost is therefore not the faculty of language, is not the memory of the words nor is it the action of nerves and of muscles of phonation and articulation, but something else. It is a particular faculty considered by
1 Broca, 1861, p. 59.
2 Ibid., p. 58
3 Ibid., p. 72.
4 Ibid., p. 49.
5 Head, 1926, I, p. 28.
6 The nomenclature of speech pathology is of no importance for present purposes, Broca called loss of speech 'aphemia'. In 1864 Trousseau proposed the term 'aphasia', and it became generally accepted. See Head, 1926, 1, 27-8. For Broca's protest and his own classification, see Broca, 1869 and below p. 206n. It is also irrelevant for this study that the lesion of aphasia which Broca localized was characteristically found in the left hemisphere. Marc Dax had pointed this out in 1836, although this remained unknown until his son pressed a claim for priority after Broca's findings, in 1864. See Head, 1926, I, 16, 28. The issue of cerebral dominance is extremely complex; however, its significance was not generally appreciated in the period under review. See Zangwill, 1960, for a recent exposition.
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M. Bouillaud to be the faculty to co-ordinate the movements which belong to the articulate language, or simpler, it is the faculty of articulate language; for without it no articulation is possible.[l]
His conception of the function also included motion.
The nature of that faculty and the place to which it should be assigned in the cerebral hierarchy could give rise to some hesitation. Is it only a kind of memory and have the individuals who have lost it, lost only, not the memory of the words but the memory of the procedure which one has to follow in order to articulate the words?[2]
These gradual perfections of the articulated language in children are due to the development of a particular kind of memory, which is not the memory of words but those of movements, necessary to articulate words. And this particular memory is not in relation with any other memory of the rest of the intelligences[3]
It might be argued, then, that speech was a motor function. Indeed this is the ground on which Jackson and Ferrier opposed Broca.
Broca discusses in detail whether speech is an intellectual or a motor function. He recognized two hypotheses for the nature of the special faculty of articulate language. 'In the first hypothesis this would be a superior faculty, and aphemia would be an intellectual disturbance. In the second hypothesis, this would be a faculty of much less elevated order and the aphemia would be only a disturbance of locomotion.' He correspondingly distinguishes 'the thinking part of the brain' from 'the motor centers of the central nervous system'.[4]
Although Broca accepted that it was an open question whether speech and aphemia involved intellectual or motor functions, he inclined to the former view. His argument reveals the prevailing assumptions. He believed that the pathological anatomy of aphemia strongly supported the view that speech is an intellectual function.
In fact, in almost all cases in which an autopsy could be performed, it was found that the substance of the convolutions is profoundly altered to a notable extent. In some subjects the lesions were even confined to the convolutions; from this one can conclude that the faculty of articulate language is one of the functions of the convolutional mass. But it is generally admitted that all faculties, called intellectual, have their seat in this part of the brain, and it seems therefore very probable, that all faculties that reside in the cerebral convolutions are of the intellectual nature.[5]
The assumption implicit in taking this evidence as deciding the issue in favour of the intellectual view rather than the motor, is made
1 Broca, 1861, p. 52.
2 Ibid., pp. 52-3.
3 Ibid., p. 54.
4 Ibid.
5 Ibid., p. 57
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explicit in Broca's discussion of the other symptoms of the patient 'Tan'. 'Everybody knows that the cerebral convolutions are not motor organs.'[l] One sees that Flourens' separation of intellectual functions from motor functions and his exclusion of the latter from the cerebral lobes had gained general acceptance by 1860. Ten years after Tan had lost the faculty of speech, a progressive right-side paralysis set in, and Broca reflects the prevailing view in saying. 'The corpus striatum of the left hemisphere is of all the attacked organs the only one where one could look for the cause of the paralysis of the two right extremeties.'[2]
It is clear that two prevailing dogmas prevented Broca from seriously entertaining the alternative position that aphasia is a motor disturbance. He could support cerebral localization, but he could not believe that the cerebral convolutions were involved in motion. They were set aside for the intellectual functions. If speech was impaired by lesions in the convolutions, it could not be a motor function. It had to be a special faculty whose nature was unspecified. It was this special status for intellectual functions-somehow different from sensory and motor functions by virtue of being intellectual-that Jackson will be seen to oppose. Nine years later Fritsch and Hitzig demonstrated experimentally that the cerebral convolutions were, in fact, motor organs.
Broca had no doubt that speech was a separate faculty.
The existence of a special faculty of articulate language-as I have defined it-can no more be doubted, because a faculty which can perish isolated without those which are in its neighbourhood is evidently a faculty independent of all others, i.e., a special faculty.[3]
If all cerebral faculties were as distinct and as clearly circumscribed as this one, one would finally have a definite point from which to attack the controversial question of cerebral localization. Unfortunately, this is not the case, and the greatest obstacle in this part of physiology comes from the insufficiency and the uncertainty of the functional analysis which necessarily has to precede the search of the organs which are coordinated to each function.[4]
The apparent discreteness of this faculty made it an ideal case for testing the question of cerebral localization. The pathological anatomy of aphemia could be used to decide if there was any localization in the brain at all and if so how discrete it was, by lobes or convolutions. If the existence of this one localization could be proved, the principle and its limits would be established.[5]
1 Broca, 1861, p. 70.
2 Ibid.
3 Ibid., pp. 54-5.
4 Ibid.
5 Ibid., p. 58.
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The second half of Broca's report is devoted to the case of 'Tan': Aphemia for twenty-one years produced by the chronic and progressive softening of the second and third convolution of the superior part of the left frontal lobe'.[1] Broca's description provides excellent data for consideration of the problems of the clinico-pathological method.[2]
The patient's history of aphemia was complicated by epilepsy since youth, diminished sensitivity and progressive paralysis of the right arm and leg over eleven years, weakened vision in the left eye, partial pharyngeal paralysis, and left-sided weakness in the extremities and face. The progressive nature of the symptoms would disqualify the patient from modern clinico-pathological studies, but Broca was prepared to infer at autopsy that the lesion began at the third left frontal convolution, where damage was worst. However, there was extensive damage, no part of the hemisphere was absolutely intact,[3] and there was generalized atrophy. In fact, as Pierre Marie later pointed out from examining the patient's brain, the inference of the locus of the original lesion was highly speculative, the examination of the patient was inadequate, and the brain was not sectioned or carefully studied at all.[4]
Broca presented a second case of the same year,[5] from which he concluded that 'the aphemia was the result of a profound, but accurately circumscribed lesion of the posterior third of the second and third frontal convolutions'.[6] In this case the aphasia was not complicated by other symptoms, and the lesion was strictly limited. Therefore the evidence was more trustworthy. By 1863 Broca and his colleagues had collected twenty cases, all showing some pathological change in the left half of the brain, and in nineteen of them it was in the third frontal convolution. Nevertheless, the presentation of a serious exception led him to reserve his opinion on the exact location of the cortical centre for articulate speech.[7]
Head reports the sensational effect of Broca's findings.
These communications produced the greatest excitement in the medical world of Paris. They were specially selected for comment by the Secretary of the Société anatomique, in his Annual Report for the year 1861. Bouillaud
1 Broca, 1861, p. 60.
2 For a presentation that concentrates more closely on the clinical description of the case and its place in the history of aphasia theory, see Head, 1926, I, 19-23, cf. Joynt, 1961.
3 Broca, 1861, p. 66.
4 Head, 1926, 1, Ch. 5; cf. Bateman, 1890, pp. 345-6.
5 Head, 1926, 1, 23-5; Bateman, 1890, pp. 22-56 Quoted in Head, 1926, I, 25.
7 Ibid., I, 26.
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and his son-in-law, Auburtin, greeted Broca as a convert to their doctrines. Localization of speech became a political question; the older Conservative school, haunted by the bogey of phrenology, clung to the conception that the brain 'acted as a whole'; whilst the younger Liberals and Republicans passionately favoured the view that different functions were exercised by the various portions of the cerebral hemispheres. During the next few years every medical authority took one side or other in the discussion.[1]
The impact of Broca's findings on the experimentalists was far less than might be supposed from the reviews of the history of cerebral localization which trace its development as a simple progression from the thesis and antithesis of Gall and Flourens to the findings of Broca and Fritsch and Hitzig which preceded Ferrier's detailed studies. Their effect on Fritsch and Hitzig and on Ferrier was confined to the suspicion it cast on Flourens' dogma of the functional equivalence of the cortex. Fritsch and Hitzig do not mention Broca by name, though his work is implied in their review of clinical studies which formed part of a slow process of doubt about the findings of Flourens and those who confirmed them. These conceptions
were modified only very gradually even by a number of well stated facts which presupposed other notions. It was known for a long time, by Bouillaud, that the complex of symptoms, now known as aphasia can be caused by destruction of a small eccentric part of the brain. Recently, several authors have contributed to define this more closely.[2]
Their only further mention of Broca's work is in acknowledging that it was the only other example of localization in the hemispheres known in 1870, and that it spoke in favour of their results.[3] However, they point out that such findings were suspicious in themselves, since they suffered from 'the faultiness and the difficult interpretations of post mortems' as compared with 'the simplicity and clearness of vivisections'.[4]
Ferrier's reaction was similar. In his first publication he does not
1 Quoted in Head, 1926, I, 25. The attention of the followers of Broca was concentrated on cases illustrating anatomical localization, rather than the phenomena of the function of speech and the changes it underwent. The concepts of aphasia and the schemes of localization that developed from them did not directly provide significant contributions to experimental localization research or to concepts of function until Head reinterpreted Jackson's work and began his own studies on the phenomena of speech function and dysfunction. It is for this reason, as much as because of my ignorance of the subtleties of clinical neurology, that I have felt able to ignore the history of aphasia in the present work. Also, the next significant step in aphasia research did not occur until 1874, when Wernicke presented his conception of sensory aphasia based on Meynert's research on the projection systems of the cortex. See Head, 1926, I, 61-3, and Freud, 1891.
2 Fritsch and Hitzig, translated von Bonin, 1870, p. 78.
3 Ibid., p. 91
4 Ibid., p. 78.
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include Broca's work as part of the inspiration of his own. He does mention Broca's finding, but only to quarrel with its interpretation. He opposes the conception that the lesion destroys a centre for 'memory of words' and suggests that only the motor channels for words are destroyed.[l] He raises the same point in the paper which he read to the Royal Society in 1874.[2] Although his original experiments were closely followed by the application of his findings to clinical cases, it is clear (as far as it can be from available manuscripts and published sources) that investigations by Broca or those inspired by his work played little part in the motivation of Ferrier's original experiments. Once he had made his initial findings he was prepared to draw on Broca for support, while mentioning their differences.
The researches of Broca and the numerous confirmations of his observations which have been put on record, taken with the results of my experiments on monkeys and lower animals, seem to me to establish the fact of a localization of the faculty of speech and to explain at least the broad features of the pathology of aphasia. I have shown that the region which governs the movements concerned in articulation is that which is the seat of lesion in aphasia.[3]
The question of the physiological interpretation of Broca's finding also enters into Ferrier's reference to it in his major work. He mentions a number of cases where considerable loss of brain substance had not involved 'apparent mental deficiency'.[4]
But the remarkable and frequent coincidence of aphasia, or loss of the faculty of speech, with softening of certain parts of the frontal region of the left hemisphere (vaguely indicated by Bouillaud and Dax, but definitely fixed by Broca in the posterior part of the third frontal convolution, and corroborated by multitudes of since recorded cases), served to render the theory of functional equivalence at least doubtful; though what aphasia really meant in physiological language, or why in symmetrically-formed hemispheres a faculty should be localized in one side to the exclusion of the other, remained a matter of mystery and dispute.[5]
This passage was expanded in the second edition to include findings of 'Bouillaud, Andral, and others' involving 'many unquestionable facts of clinical medicine, such as limited paralysis in connection with limited cerebral lesions, which appeared wholly inexplicable except
1 Ferrier, 1873, p. 74.
2 Ferrier, 1874, p. 129.
3 Ferrier, 1874b, pp. 54-5, -f. p. 56.
4 Ferrier, 1876, p. 126.
5 Ibid.
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on the hypothesis of a differentiation of function in the cerebral hemispheres'.[l] His description of these cases-even with the knowledge of hindsight-indicated that their significance was limited to the doubt they cast on the theory of functional equivalence.
These exponents of the new experimental physiology of sensation and motion were suspicious of both the correlative method and the unphysiological conceptions of clinical workers. The method of correlating clinical and pathological phenomena was uncomfortably reminiscent of the dangers of craniological correlations, even though they were based on direct observations of the brains. Experiment was the only trustworthy method. Ferrier's view of the dangers of clinical observations as compared with the trustworthiness of animal experiments has been mentioned.[2] He remained quite cautious about the 'facts furnished by the experiments of disease in man'.[3]
These, however, require to be handled with the utmost caution, otherwise they may be made to support almost any doctrine however absurd. Almost every form of disturbance of the cerebral functions has been manifested in conjunction with anatomical lesions of the utmost diversity as to character, size, and position; and likewise without any visible or demonstrable lesion whatever. In the absence of any exact means of discrimination between the direct and indirect effects of pathological lesions, or of the relation between functional disturbance and structural alteration, little reliance can be placed on localisation of function founded on the positive facts of cerebral disease alone. Clinical cases are mainly valuable as confirmatory of physiological experiments, and more especially as supplying negative instances.[4]
A case of total destruction of an area without loss of function is significant, since it conclusively refutes a relationship between the area and its supposed function, but otherwise, clinical cases offer little help to the physiologist. Gall had seen cases of 'accidental mutilation' as useful only in confirming his cranioscopic findings. Bouillaud and Broca made clinico-pathological correlations their basic approach, and Auburtin voiced their faith in this approach in favour of the experimental one of producing effects by controlled stimulation or ablation. Fritsch and Hitzig and Ferrier complete the change in methodological faith by subordinating clinical cases to a confirmatory role.
Looking backward from the vantage point of Ferrier's work it is clear that the view of localization that was most closely akin to Gall's in conception, though not in method of localization, was least influential
1 Ferrier, 2nd ed., 1886, p. 222.
2 Above, pp. 52-3; cf. below, pp. 236-8.
3 Ferrier, 1886, p. 270.
4 Ibid., cf. Ferrier, 1890, pp. 15-17.
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on the experimental work of the sensory-motor psychophysiologists. The terms in which Ferrier thought of localization were also derived in a circuitous route from phrenology by way of Spencer and Hughlings Jackson. It will become clear in reviewing the development of this work that Broca's role was that of a foil for the precise statement of Jackson's sensory-motor view. The other source of Ferrier's concept of localization was the finding of Fritsch and Hitzig, who were also indirectly indebted to Broca. However, their contribution involved use of the experimental method to disprove exclusion of the cortex from motor functions: the proposition that had been central to Broca's view of both aphasia and the functions of the hemispheres. In conclusion, Broca can be credited with having provided important pathological support for belief in some form of localization, in opposition to one of the prevailing doctrines of Flourens in cerebral physiology, while his conception of the 'faculty' perpetuated another. Any statement beyond this involves conceptions that can be related to Broca's views only by contrast.