tTIENNE GEOFFROY SAINT-HILAIRE. 407 



new." Sickness in 1812, and the disasters of the country in 1813-'14, 

 interrupted his scientific work. In 1815 he was chosen a representative 

 by the electors of Etampes, and performed the functions of his office 

 with credit, till the Restoration put an end to them. Restored to sci- 

 ence, he expounded his system in a work entitled " Philosophic Ana- 

 tomique " (" Anatomical Philosophy "), the first volume of which, treat- 

 ing of the respiratory organs and skeletons of vertebrates, appeared in 

 1818. The second volume, devoted to researches on human monstrosi- 

 ties, was published in 1822. The dominant feature of these two vol- 

 umes was the principle of unity of composition. This principle was 

 not entirely new to science. It had been glanced at by Aristotle, 

 Pierre Belon, Newton, Buffon, and Vicq-d'Azyr ; but it remained for 

 Geoff roy Saint-Hilaire to create a theory embodying the views which 

 they had only mentioned sporadically. 



Previous to him, naturalists, giving more particular attention to 

 human anatomy, recognizing only forms, and regarding each new form 

 as a new organ, had multiplied details infinitely without discovering 

 any general law. " The first step toward rising to the ideal type of 

 a vertebrate animal," says M. Flourens, in his eulogy before the Acad- 

 emy, " was to get free from every preconception in favor of human 

 anatomy, as the only means of being able to regard the organs under 

 their more general conditions, aside from the merely relative consider- 

 ations of form, volume, and use." Geoffroy was convinced that iden- 

 tities can bear only upon relations, and had in this rule, which he 

 called the principle of connections^ an infallible guide through all 

 metamorphoses, capable of unmasking the most strangely disguised 

 affinities. Thus, whenever two parts agreed in having similar relations 

 and dependencies, they were analogous. With this precept, Geoffroy 

 was able to declare that the materials found in one family exist in all 

 the others, and to proclaim his law of unity as a law of nature. In his 

 second volume he extended the application of his principle to the for- 

 mations called monstrosities, which he declared were not original 

 anomalies, but simply cases of abnormal or of incomplete development 

 of some particular part. 



As long as the principle of unity was applied simply to vertebrates 

 it was incontestable, and excited no contradiction ; but when Geoffroy 

 Saint-Hilaire began to extend it to invertebrates he encountered a vig- 

 orous adversary in Cuvier, whose work it had been to emphasize the dis- 

 tinctions between the groups which his former patron was trying to re- 

 duce to unity. When Geoffroy, in 1820, brought the articulates under 

 his general type, Cuvier uttered words of impatience and disapproval ; 

 but, when in 1830 he proposed to include the mollusks, the long latent 

 contention broke out. " Never," says M. Flourens, " did a more vital 

 controversy divide adversaries more resolute, more firm, or who had 

 by long preparation provided themselves with more resources for the 

 combat, and (if I may say it) more learnedly prepared not to agree." 



