Geoffroy Saint-Hilaire

Geoffroy Saint-Hilaire, Etienne (1772-1844), famous French naturalist whose views on the unity of animal organization in large measure prepared the acceptance of evolutionary theory. During the Great French Revolution the Convention established at the Jardin des Plantes 12 chairs, one of which (zoology of vertebrates) was occupied by the then young mineralogist G. S.-H. He became the founder of the zoological museum and zoological garden. In 1798 he took part in Bonaparte's expedition to Egypt, organizing there extensive research and collection of zoological and archaeological collections. In 1808 he was sent to Portugal with a mission to use for France the collections of museums and institutions of Lisbon and organized a voluntary exchange of duplicates and scientific services between countries. In 1809 G. S.-H. received the chair of zoology and comparative anatomy at the Faculté des Sciences. The scientific works of G. S.-H. are numerous and multifaceted. He wrote many monographs on fish, reptiles and especially mammals. Engaging primarily in vertebrates, G. S.-H. was struck by the unity of their plan. He pointed out already in early works that in different organisms there is always a tendency for the appearance of the same elements, including in the same connection with each other (the law of connections). This "unity of plan" allowed him to draw analogies between different parts of the skeleton and other organs of vertebrates, however much they might differ in size, form and function from each other (the theory of analogies). If at the same time one organ or part of it increases, then another, neighboring one decreases at the same time. By this "law of balance of organs" G. S.-H. explained the existence of "rudimentary" organs. An important contribution of G. S.-H. was that he took for comparison also the embryos of vertebrates. This led him to some discoveries (rudiments of teeth in toothless whales). The main theoretical work of G. S.-H. is the "Philosophie anatomique", in which the goal of science is set as the synthesis of phenomena by means of the method of analogies. Using it, G. S.-H. sought elements of the vocal apparatus in fish, elements of gill covers in terrestrial animals, rudiments of teeth in birds. The law of unity of plan G. S.-H. also applied to invertebrates. Thus, he equated the general arrangement of viscera, present in vertebrates, to the arrangement in invertebrates, but in reverse order. The abdomen of insects with the nerve cord running along it, in his opinion, is analogous to the back of vertebrates with the spinal cord, just as the ventral side of vertebrates with the heart is analogous to the back of insects, where their heart is located. A contribution of G. S.-H. are the systematic studies of monstrosities (he was one of the founders of "teratology"), which he did not consider as a "game of nature" but as phenomena subject to the same laws as normal organisms. The cause of them he considered as a delay or disturbance in the development of certain organs or parts of the body. G. S.-H., considering all organisms as variations of the same plan and function as a consequence of organization, and not as a cause, naturally reacted negatively to the doctrine of the immutability of species, thinking that the "environment" greatly changes the organization. However, the limits of these changes were unclear to him. It occurred to him that modern forms could have originated in the course of centuries from fossil forms; his later works are devoted to fossil reptiles, to which he applied this idea. However, G. S.-H. did not give a general theory of evolution, and the famous dispute of his in the Academy of Sciences with Cuvier in 1830 was not, as is often represented, a dispute between an evolutionist and an opponent of evolution. The dispute was conducted in an entirely different plane—whether animals are constructed according to one plan and on the relative significance of synthesis and analysis in science. And if Cuvier was right in this dispute, rejecting the single plan of structure of all animals and pointing to "certain erroneous generalizations of G. S.-H., then the latter was undoubtedly right in refuting the doctrine of the immutability of species, rejecting the teleological views of Cuvier on the organism and advancing the significance of generalizations in biology and that comparative-anatomical method which played such a role later in the construction of evolutionary comparative anatomy. Some of the views of G. S.-H. in more recent times have been incorrectly attributed to Lamarck. Under the name of Lamarckism is often meant the doctrine of the change of species under the influence of external conditions. Kholodkovsky convincingly showed that this doctrine would more correctly be called " Geoffroyism", since according to Lamarck at least animals do not change as a result of the direct influence of the environment, but under the influence of psychological moments, aspirations, etc. Main works of Geoffroy Saint-Hilaire: "Philosophie anatomique" (v. I-II, Paris, 1818-22); "Principes de philosophie zoologique" (Paris, 1830).