Broca's Brain - Carl Sagan [6]
Paul Broca died in 1880, perhaps of the very sort of aneurism that he had studied so brilliantly. At the moment of his death he was working on a comprehensive study of brain anatomy. He had established the first professional societies, schools of research, and scientific journals of modern anthropology in France. His laboratory specimens became incorporated into what for many years was called the Musée Broca. Later it merged to become a part of the Musée de l’Homme.
It was Broca himself, whose brain I was cradling, who had established the macabre collection I had been contemplating. He had studied embryos and apes, and people of all races, measuring like mad in an effort to understand the nature of a human being. And despite the present appearance of the collection and my suspicions, he was not, at least by the standards of his time, more of a jingoist or a racist than most, and certainly not that standby of fiction and, more rarely, of fact: the cold, uncaring, dispassionate scientist, heedless of the human consequences of what he does. Broca very much cared.
In the Revue d’Anthropologie of 1880 there is a complete bibliography of Broca’s writings. From the titles I could later glimpse something of the origins of the collection I had viewed: “On the Cranium and Brain of the Assassin Lemaire,” “Presentation of the Brain of a Male Adult Gorilla,” “On the Brain of the Assassin Prévost,” “On the Supposed Heredity of Accidental Characteristics,” “The Intelligence of Animals and the Rule of Humans,” “The Order of the Primates: Anatomical Parallels between Men and Apes,” “The Origin of the Art of Making Fire,” “On Double Monsters,” “Discussion on Microcephalics,” “Prehistoric Trepanning,” “On Two Cases of a Supernumerary Digit Developing at an Adult Age,” “The Heads of Two New Caledonians” and “On the Skull of Dante Alighieri.” I did not know the present resting place of the cranium of the author of The Divine Comedy, but the collection of brains and skulls and heads that surrounded me clearly began in the work of Paul Broca.
BROCA WAS a superb brain anatomist and made important investigations of the limbic region, earlier called the rhinencephalon (the “smell brain”), which we now know to be profoundly involved in human emotion. But Broca is today perhaps best known for his discovery of a small region in the third convolution of the left frontal lobe of the cerebral cortex, a region now known as Broca’s area. Articulate speech, it turns out, as Broca inferred on only fragmentary evidence, is to an important extent localized in and controlled by Broca’s area. It was one of the first discoveries of a separation of function between the left and right hemispheres of the brain. But most important, it was one of the first indications that specific brain functions exist in particular locales in the brain, that there is a connection between the anatomy of the brain and what the brain does, an activity sometimes described as “mind.”
Ralph Holloway is a physical anthropologist at Columbia University whose laboratory I imagine must bear some resemblance to Broca’s. Holloway makes rubber-latex casts of the insides of skulls of human and related beings, past and present, to attempt a reconstruction, from slight impressions on the interior of the cranium, of what the brain must have been like. Holloway believes that he can tell from a creature’s cranium whether Broca’s area is present, and he has found evidence of an emerging Broca’s area in the brain of Homo habilis some two million years ago—just the time of the first constructions and the first tools. To this limited extent there is something to the phrenological vision. It is very plausible that human thought and industry went hand in hand with the development of articulate speech, and Broca’s area may in a very real sense be one of the seats of our humanity, as well as a means for tracing our relationships with our ancestors on their way toward humanity.
And here was Broca’s brain floating, in formalin and in fragments, before me. I could make out the limbic region