Etienne Geoffroy Saint-Hilaire, 1772-1844: A Visionary Naturalist (review)

The names of certain scientists are forever linked. Some, like Watson and Crick, are linked because of their joint contributions. Others, like Georges Frédéric Cuvier (1769-1832) and Étienne Geoffroy Saint-Hilaire (1772-1844), are linked because of their opposition to each other. Cuvier and Geoffroy started their careers as friends; they ended up as bitter enemies. The two could not have been more different and yet more similar. Cuvier was an arch career scientist. He held powerful positions in just about every scientific society. Geoffroy was more other- worldly.Yet they both worked in comparative anatomy and natural history.Their chief difference was that Cuvier thought that all animals could be subdivided into four and only four embranchments—Vertebrata, Articulate, Mollusca, and Radiata—while Geoffroy thought that these four embranchments could be combined to form a single plan.

This difference in opinion is likely to strike most present-day readers as trivial. "One, two, three or four embranchments? What difference does it make?" But it did make a difference to anatomists at the time. They viewed the discovery of these plans as akin to Newton discovering his law of universal gravitation. A variety of formerly distinct phenomena were joined together under this one great law—the moon circling the earth, lead balls rolling down inclined planes, and the proverbial apple falling on Newton's head. Geoffroy saw himself as doing much the same thing. He was simply reducing Cuvier's four embranchments to a single law, Geoffroy's law of universal forms or unity of plan. Cuvier had a hard enough time showing that all Radiata—the echinoderms, coelenterates, and some simple invertebrates—exhibited a single fundamental plan without trying to include all animals in a single form. Codfish, shrimp, clams, and a sea cucumbers all exhibit the same plan?

This disagreement was carried on for years in the academic world of Paris. It peaked initially in 1830, then subsided, only to come to a head again. Cuvier died while writing one more response to Geoffroy. Most present-day readers are not likely to be all that fascinated by forms and how they are related to each other: this just does not sound like science as we know it. But the debate soon evolved into a disagreement over transmutation. Cuvier was a "fixist." He rejected any transformation (what we would call evolution) within a particular embranchment, and he certainly rejected any transformation between embranchments. Since Geoffroy thought that all animals exhibit the same fundamental plan, he saw no reason why all organisms could not have evolved from a single progenitor.Thirty years later Darwin concluded his Origin of Species with the observation that there is a "grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one." Later Darwin dropped his sacerdotal reference and opted for a single progenitor.

In his study of Geoffroy, Hervé Le Guyader intersperses his views on the Cuvier-Geoffroy controversy with publications by these two adversaries. Most of the papers reprinted in this volume are by Geoffroy and were presented during the height of the 1830 debate, but some were published earlier and two present Cuvier's views. The anthology concludes with three funeral orations and Guyader's evaluation of the debate a century and a half later. Guyader's final comments are a bit Whiggish, as he strives to salvage Geoffroy's reputation by showing how similar some of his ideas are to those that we hold today, but in general these papers, translated for the first time by Marjorie Grene, present a well-rounded idea of one of the major debates in the history of science.