180 FAMOUS GEOLOGISTS/Cuvier named him Pair de France in 1831 Cuvier was a member of three sections of the Institut de France: the Acade´ mie Franc¸ aise, the Acade´ mie des Sciences, and the Acade´ mie des Inspections et Belles-Lettres, as well as numerous foreign academies In 1803, Cuvier married the widow of the former fermier ge´ ne´ ral Duvaucel, who had been guillotined in 1793 None of their four children survived, and their deaths caused Cuvier great distress Cuvier died on 13 May 1832, at the height of his fame, after a short illness, the precise nature of which is unknown (although it may have been cholera or myelitis) Cuvier’s Work and Achievements The eighteenth and nineteenth centuries were dominated by a desire to emulate the astronomical achievements of Newton in other areas of science Cuvier aspired to be the Newton of natural history He wanted to introduce into this field the approach that henceforth would govern all physical sciences: analyse facts, isolate them, compare them, and then try to ascertain general causes to explain the facts thus ordered according to common laws or principles His best-known law – the one that made possible his fossil reconstructions – was the law of the correlation of organs or parts: all the parts of an organism must be suitably correlated so as to make a viable whole, capable of coping with the conditions of existence He adopted the ‘comparative’ approach in the late eighteenth century when endeavouring to restore the remains of mastodons that had been sent to France from America for examination The task was accomplished using anatomical analogies with modern elephants (for which he regarded the African and Indian types as being distinct, as were the remains of the Siberian mammoth) Applying this principle, Cuvier succeeded in reconstructing a large number of extinct forms A single tooth, so to speak, told him everything about an organism, he triumphantly proclaimed apropos his reconstruction of the Mosasaurus The immutable laws of zoology, with their wonderful constancy, which are not contradicted in any class or family, served Cuvier admirably in his arduous task of ‘resurrecting’ (his word) the past The notion of species obviously underpinned all attitudes towards, and classifications of, animated nature It was one of the most clearly defined concepts in Cuvier’s work The most important concepts in nature were those of the individual and the species, and they were connected through the process of generation Organized beings had two bases for natural classification: the individual, resulting from the common action of all the organs; and the species, resulting from the bonds created by the generation of individuals From his earliest publications, and particularly in his Tableau E`le´ mentaire de l’Histoire Naturelle des Animaux (published in 1797), Cuvier gave a definition to which he remained steadfast: The collection of all organized bodies born one from another, or having parents in common, and all those that resemble them in the same way as they resemble each other, is called a species [Cuvier G (1797) Tableau E`le´ mentaire de l’Histoire Naturelle des Animaux Paris: Baudouin p 11] But, in practice, in many cases – and whenever considering the past – one cannot use the descent of forms to define species So, they must be classified by their distinctive external, and more particularly their internal, parts Form becomes the prime consideration in the study of living bodies, and gives anatomy a role that is almost as important as that of chemistry Although Cuvier seems at times to have supposed that there was really nothing in nature other than the species and the individual, nevertheless the study of living forms led him to ascribe a concrete reality to another type of organization, namely that of embranchements An embranchement was an ensemble of animal forms that had a common structural plan, which served as the basis for all external modifications Cuvier’s four embranchements-vertebrates, molluscs, articulata (jointed or segmented animals), and zoophytes or radiata-are still well known If there was a ‘closed system’ in Cuvier’s mind it would seem to have been in systematics, at the level of the embranchements Each of these formed a separate whole; there was no transition or gradation from one embranchement to another Other organisms would not be viable because they would not meet the conditions of existence The ‘construction plans’ of the different embranchements were entirely different There is, for example, no passage from vertebrates to molluscs Whatever arrangement is given to animals with back bones and those without them, one can never place one of their large classes at the end of one group, and some what similar animals at the head of the other so that the two are linked together [Cuvier G (1800) Lec¸ ons d’Anatomie Compare´ e: Paris: Baudouin p 60] Similarly, There can be no intermediary between mollusca and articulata, nor between them and the radiata, for one cannot fail to recognise the profound interval or ‘salta tion’ there is when one passes from one construction plan to another It was in this spirit that Cuvier undertook the palaeontological investigations for which he became famous