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(Archives S. Nicolas)

Paul Broca (1824–1880) has long been credited with localizing language in the inferior gyrus of the left frontal lobe.

Today, damage to this region is often called Broca’s aphasia.

During the December 20, 1860, session at the Anthropological Society of Paris, the physiologist Louis Pierre Gratiolet (1815–1865) presented the skull of a Totonac Indian from the Gulf of Mexico. The parietal lumps of this skull were very prominent, and the forehead was very narrow and low, which resulted in the anterior parts of the cerebral lobes not being particularly developed (Gratiolet, 1860, p. 562). Still, this individual’s cranial capacity was similar to that of a white person, and the rather complex structure of the skull revealed slow ossification, as occurred in the white races. In a later session (February 21, 1861), Gratiolet (1861) mentioned the study of the Totonac skull again and concluded by saying that there is no relationship between the development of intelligence and the encephalic mass. Taking Descartes’s small cranial capacity as an example, he claimed that it is “the form and not the volume that determines the brain’s dignity” (p. 71). Broca (1861a) attacked two suggestions made by Gratiolet during the preceding sessions: (1) brain volume considered either in individuals or in races has almost no meaning; it is the shape and not the cerebral mass that is related to intelligence; (2) as the organ of thought, the brain is a single element, just like thought itself; the different parts making up the brain do not have different functions corresponding to various faculties of the mind. Broca went on to present his ideas on cerebral localization. Even though he denied any direct and intellectual relationship with phrenology, he acknowledged that Gall had shown the way.

Broca did not think that the collapse of Gall’s cranioscopic system or phrenology had destroyed the principle of cerebral localization. He then wondered how research on this principle should proceed; he thought that only pathological observations, complemented with autopsy studies, could lead to the discovery of particular localizations, provided that future observers described the diseased convolution using regular anatomical names, rather than the vague indications used to describe lesions in this or that area of the brain in the past. In his view, the highest faculties of intelligence were located in the anterior lobes. And of all faculties, it was for speech was the one where it was easiest to recognize a loss.

Aphasia: The Leborgne (Tan) and Lelong (1861) Cases

A few days later, on April 11, 1861, a 51-year-old man named Leborgne who was incapable of speaking was brought into the surgery department where Broca worked. The autopsy of this patient was to provide crucial evidence on the localization question that was being discussed at the time. Leborgne died a few days later, and Broca (1861b) marked an epoch in the history of cerebral localization when he presented a communication to the Anthropological Society entitled “Loss of speech, chronic softening, and partial destruction of the left anterior lobe of the brain” on April 18, 1861. On this occasion, he presented the brain of Leborgne, who had lost the ability to speak 21 years earlier. He could no longer pronounce more than a single syllable, which he usually repeated twice in a row. No matter what question he was asked, he always answered tan, tan, accompanied by various expressive gestures. Because of this, he was known as Tan throughout the hospice. It should be added that anger increased his vocabulary, adding the curse “God’s holy name.” At autopsy, it was found that the speech loss was caused by a lesion in the frontal lobe.

The complete publication of the observation, accompanied by new ideas and the appearance of the word aphemia, only occurred later at the Anatomical Society. In the article entitled “Comments on the site of the faculty for speech, followed by an observation of aphemia” published in August 1861 in the Bulletin de la Société anatomique, Broca (1861c) did indeed use the name aphemia for this particular kind of loss of speech which represented neither a destruction of intelligence nor a paralysis of the articulatory muscles. The postmortem examination of the aphemic Tan’s brain allowed Broca to support conclusions regarding the role of frontal lesions; in addition, thanks to his anatomical knowledge, he attempted to determine the specific area of this lobe which was the putative site of the faculty of speech. He first stressed that it was the posterior part of the frontal lobe that was mainly altered, whereas the orbital part was intact.

Broca remained cautious when he published the anatomo-clinical case of Lelong that same year in an article entitled: “New observation of aphemia caused by a lesion of the posterior half of the second and third left frontal convolutions,” published in the Bulletins de la Société d’Anatomie (Broca, 1861d). During the April 3 session at the Anthropological Society (Broca, 1863), Broca acknowledged that all eight of the aphasic patients he had observed had a lesion in the left cerebral hemisphere. At the end of the first half of 1863, Broca gathered 25 cases of aphemia coinciding with lesions in the left hemisphere, without finding a single case of aphemia coinciding with lesions in the right one. These new observations established Broca’s conviction for good, as he declared at the Surgical Society on February 24, 1864: “From the results of autopsies, I have been impelled to consider the posterior part of the frontal convolution to be the almost exclusive site of aphemic lesions.” (cited on March 5 in La Lancette Française. Gazette des Hôpitaux Civils et Militaires, 37, p. 107).

In 1865, Broca had solid grounds for affirming the role of the third frontal convolution and demonstrating the reality of the left hemisphere’s functional preeminence for language. This affirmation took place in the context of the Dax-Broca controversy concerning the localization of aphasia (aphemia). It was at this time that the term aphasia first appeared in the medical literature. It should be remembered that it was Trousseau (1864) who introduced the word aphasia in his classes on clinical medicine, at the suggestion of Dr. Chrysaphis and the eminent scholar Émile Littré (1801–1881), while he was developing his own theory of language disorders. On this naming issue, Broca (1864), who was attached to the term aphemia, defended it in vain in a letter to Trousseau; the letter contained theoretical questions in addition to philological arguments, concerning for example the true nature of the disorder. Trousseau’s successful attempt was most likely due to his hostility towards and jealousy of Broca.

References

Broca, P. (1861a). Sur le volume et la forme du cerveau, suivant les individus et suivant les races (séances du 21 mars et 02 mai).Bulletins de la Société d’Anthropologie de Paris, 2, 139–204; 308–321.

Broca, P. (1861b). Perte de la parole, ramollissement chronique et destruction partielle du lobe antérieur gauche du cerveau.Bulletin de la Société d’Anthropologie, 2, 235–238.

Broca, P. (1861c). Remarques sur le siège de la faculté du langage articulé; suivies d’une observation d’aphémie (perte de la parole). Bulletins de la Société Anatomique de Paris, 36, 330–357.

Broca, P. (1861d). Nouvelle observation d’aphémie produite par une lésion de la moitié postérieure des deuxième et troisième circonvolutions frontales. Bulletin de la Société Anatomique de Paris, 36, 398–407.

Broca, P. (1863). Localisation des fonctions cérébrales. Siège de la faculté du langage articulé (3 avril). Bulletin de la Société d’Anthropologie de Paris, 4, 200–202.

Broca, P. (1864). Lettre à M. le professeur Trousseau sur les mots aphémie, aphasie et aphrasie (23 janvier). La Lancette Française. Gazette des Hôpitaux Civils et Militaires, 37, 35–36.

Broca, P. (1865). Sur le siège de la faculté du langage articulé (15 juin). Bulletins de la Société d’Anthropologie de Paris, 6, 377–393.

Gratiolet, P. (1860). Sur le crâne d’un Totonaque (séance du 20 décembre). Bulletins de la Société d’Anthropologie de Paris,1, 562–565.

Gratiolet, P. (1861). Sur la forme et la cavité crânienne d’un Totonaque, avec réflexions sur la signification du volume de l’encéphale. Bulletins de la Société d’Anthropologie de Paris, 2, 66–71 (discussion pp. 71–81).

Schiller, F. (1993). Paul Broca: Founder of French anthropology, explorer of the brain (first published 1972). Oxford: Oxford University Press.

Trousseau, A. (1864). De l’aphasie. Maladie décrite récemment sous le nom impropre d’aphémie. La Lancette Française. Gazette des Hôpitaux Civils et Militaires, 37, no. 4, 12 janvier, 13–14; no. 7, 19 janvier, 24–26; no. 10, 26 janvier, 37–39; no. 13, 2 février, 49–50.