Étienne Geoffroy Saint-Hilaire was a French naturalist. He was a professor of zoology at the University of Paris.
Background
Étienne Geoffroy was born on April 15, 1772, in Etampes, France. He was the son of Jean Gerard Geoffroy, procurator and magistrate of Etampes. Etienne received as a child the surname Saint-Hilaire, which he later joined to his family name.
Education
Étienne studied natural philosophy under Mathurin Jacques Brisson at the Collège de Navarre (Its buildings were assigned to the École Polytechnique by Napoleon in 1805) in Paris. Having taken the degree of bachelor in law, he became a student of medicine and attended the lectures of Antoine François de Fourcroy at the Jardin des Plantes, and of Louis-Jean-Marie Daubenton at the College de France.
Career
In June 1793 the Jardin des Plantes became the Museum d’Histoire Naturelle. And it was then, owing to his patrons, that Geoffroy, barely twenty-one years old, was named professor of quadrupeds, cetaceans, birds, reptiles, and fish. He became an intimate friend of Lamarck - his elder by almost thirty years - a botanist promoted to the study of insects, worms, and crustaceans. Each of them eagerly explored his new field.
In 1794, Geoffroy entered into correspondence with Georges Cuvier. Shortly after the appointment of Cuvier as an assistant at the Museum d'Histoire Naturelle, Geoffroy received him into his house. The two friends wrote together five memoirs on natural history, one of which, on the classification of mammals, puts forward the idea of the subordination of characters. It was in a paper entitled Histoire des Makis, ou singes de Madagascar, written in 1795, that Geoffroy first gave expression to his views on the unity of organic composition.
When Bonaparte organized the famous Egyptian campaign, he requested the assistance of numerous scientists. Cuvier avoided leaving, but Geoffroy accepted enthusiastically, and from 1798 to 1801, in the midst of adventures in which he often risked his life, he made many scientific observations. Returning to Paris, Geoffroy devoted himself from 1802 to 1806 to descriptive zoology and classification, despite his predilection for great theoretical views. He pursued the research on the marsupials that he had begun in 1796. He also composed a large catalog of the mammal collections of the Muséum, the printing of which he stopped suddenly at page 212 in 1803, perhaps as a result of differences with Cuvier.
After his appointment as professor of zoology at the University of Paris in 1809, Geoffroy began the anatomical studies that he would later summarize in Philosophie anatomique, published for the first time in 1818. The second volume came out in 1820. From 1802 to 1840 he devoted more than fifty reports, to descriptive teratology. Moreover, his Essai de classification des monsters marks the debut of scientific teratology. He resigned his chair at the museum in 1841 and was succeeded by his son, Isidore Geoffroy Saint-Hilaire.
Religion
Geoffroy was a deist, which is to say that he believed in a God, but also in a law-like universe, with no supernatural interference in the details of existence. This kind of opinion was common in the Enlightenment, and goes with a rejection of revelation and miracles, and does not interpret the Bible as the literal word of God. These views did not conflict with his naturalistic ideas about organic change.
Views
Geoffroy's theory was not a theory of common descent, but a working-out of existing potential in a given type. For him, the environment causes a direct induction of organic change. This opinion Ernst Mayr labels as 'Geoffroyism'.
Geoffroy endorsed a theory of saltational evolution that monstrosities could become the founding fathers of new species by an instantaneous transition from one form to the next. He speculated that birds could have arisen from reptiles by epigenetic saltation. Geoffroy wrote that environmental pressures could produce sudden transformations to establish new species instantaneously. It was later called heterogenesis.
Geoffroy also noted that the organization of dorsal and ventral structures in arthropods is opposite that of mammals. The inversion hypothesis was met with criticism and was rejected, however, some modern molecular embryologists have since resurrected this idea.
Membership
In 1807 Geoffroy entered the Académie des Sciences.
Personality
Physical Characteristics:
In July 1840, Geoffroy became blind, and some months later he had a paralytic attack. From that time his strength gradually failed him.