FROM LAMARCK TO ST. HILAIRE 227 



Linmuus to the flora of France. He seems to have 

 been gifted with the power of exceptionally rapid 

 observation, with great facility in writing, and 

 with unusual powers of definition and descrip- 

 tion. 



At the age of forty-nine Lamarck was trans- 

 ferred, under the Directory, to a zoological chair 

 in the Jardins des Plantes, where he was espe- 

 cially placed in charge of the invertebrates ; at the 

 same time Geoffroy St. Hilaire was appointed to 

 the care of the vertebrates. Lamarck took up the 

 study of zoology with such zeal and success that 

 he almost immediately introduced striking re- 

 forms in classification. The early fruits of his 

 zoological studies were not only a series of very 

 valuable additions to the classification of animals, 

 such as the divisions, Vertebrata and Inverte- 

 brata, and the groups, Crustacea, Arachnida, and 

 Annelida, but the rapid development of a true 

 conception of the mutability of species, and of 

 the great law of the origin of species by descent. 



His devotion to the study of the small forms 

 of life, probably with inferior facilities for work, 

 gradually deprived him of the use of his eyes, 

 and in 1819 he became completely blind. The 

 last two volumes of the first edition of his His- 

 toire Naturellc des Animaux sans Vcrtchrcs, 

 which was begun in 1815 and completed in 1822, 

 were carried on by dictation to his daughter, who 



