(1824–80). French surgeon and anthropologist, professor of surgery and anthropology in Paris. Broca was the only son of a doctor at Sainte-Foy-la-Grande, a small town in the Gascogne, on the river Dordogne, east of Bordeaux. He is remembered chiefly for establishing in 1861 that destruction of an area of grey matter not much larger than 4 square centimetres — 'Broca's area' — makes a person unable to speak — Broca's (expressive or motor)
aphasia, by him first called 'aphemia'. In practically all right-handed people this area, he also found, lies in the left hemisphere; hence it is called the 'dominant' hemisphere of the brain. His test case was a patient nicknamed 'Tan', because 'tan-tan' were the only syllables he could produce for an answer. By contrast, Tan's understanding of the spoken word was considered to be intact. For years Tan had also been paralysed on the right side — presumably through a succession of strokes — and had become Broca's surgical patient because of an infected bedsore. He soon died. At autopsy his brain showed the essential lesion situated at the hind end of the third, or inferior, of the three frontal lobe convolutions (or gyri). Here, for the first time, it was demonstrated with fair precision that a small set of muscles as well as a mental function — the expression of ideas through words — could be localized in a fairly circumscribed portion of brain tissue. The observation has been confirmed innumerable times since. (In 1870 Gustav Fritsch and J. L. Hitzig localized motor function,
Carl Wernicke three years later a receptive speech area.) Before Broca established this localization, only a few diehards had been upholding
Franz Joseph Gall's vague contention of half a century earlier that the frontal lobes generally 'preside over the faculty' of speech.
Broca's other major contribution to understanding the relationship between the structure of the brain and mental function concerns what in the 1950s was revived under the designation of the '
limbic system'. This comprises the convolutions of the inner wall of the cerebral hemispheres and part of the inferior aspect of the frontal lobes. Broca based his concept of the 'great limbic lobe' on the fact that it is relatively underdeveloped in aquatic mammals and primates, including the human, as compared with lower mammals, which rely to a much greater extent on the sense of smell, and have otherwise less developed hemispheres. On this basis Broca contrasted a 'brute' part with an 'intelligent' part of the brain. Today the limbic (threshold) system is recognized for being concerned with emotion, instinct, and visceral control.
When in 1859 — also the year of
Darwin's publication of
The Origin of Species — Broca was prevented in the Société de Biologie from reading a series of his papers (considered too revolutionary as they negated the permanence of species), he founded the Société d'Anthropologie (the first under this name), and later a laboratory, museum, and institute. One of the papers was based on a study of fertile 'leporids', so called in France because they were a cross between a hare and a female rabbit.
Broca also first described Cro-Magnon and Aurignacian, or palaeolithic, man, developed a large number of instruments for measuring skulls (craniometry), employed the novelty of statistical standardization, and lent the budding science of anthropology his eminently critical spirit. He inaugurated the study of prehistoric trephining of the skull, and exploded the 'Celtic myth' (that the Celts constitute a racial group with inherited characteristics) and other racial prejudices: 'Spread education, and you improve the race,' were his words. In his early years he belonged to a small group who used the microscope to detect cancer cells, and he discovered their spread via the venous system. He published some 500 papers but his only major book was a standard monograph on aneurysms.
He was also active in political life, holding radical views. He was elected to the French Senate in 1879, but died one year later having delivered only one memorandum, which pleaded to grant public high-school education to females. He was sceptical about the prevalent view of equating female inferiority with the female's relatively smaller brain: 'An enlightened person cannot think of measuring intelligence by measuring the brain,' he wrote.
(Published 1987)— Francis Schiller
