152 GEOLOGICAL BIOLOGY. 



ishment, etc., might produce new species, and the term evo- 

 lution, in its general sense, appears to have been first proposed 

 by him. 



Lamarck (i 744-1 829) definitely adopted this view, and 

 under the name of Mutability of Species. The term Develop- 

 ment was also used by him to express the formation of new 

 species from pre-existing species by gradual modification, and 

 the theory was elaborately expounded by him.* 



The restricted use of the word Evolution (as adopted in 

 this treatise) meaning the gradual and progressive change in 

 the form of species, as distinct from the development of the 

 individual organism from the embryo upward, to which 

 Lamarck also likened it, was first adopted, it is believed, by 

 Etienne Geofp^ROY St. Hilaire in 1825, in a report of his 

 travels in Egypt ; and the idea was finally elaborated in a book 

 published in 1831, entitled " Memoire sur le degre d'influence 

 du monde ambient pour 'modifier les formes animales." He 

 maintained the principles of mutability of species, common 

 descent of individual species from common primary forms, and 

 the unity of their organization, or unity of plan of structure. 



Lamarck was prominent for the promulgation of the 

 theory of the mutability of species, and there was warm dis- 

 cussion between the Lamarckian and Cuvierian schools long 

 before Darwin produced the " Origin of Species." But before 

 either of these great naturalists the philosophical notion of 

 mutation of organic forms had been definitely announced. 

 In the Ionian school Anaximander (61 1-547 B.C.) expressed 

 the view as a philosophical conception. In describing the 

 origin of things he gave utterance to the theory that out of 

 the vague indeterminate first principle by successive trans- 

 mutation man and animals have sprung. 



Philosophical Importance of the Transmutation Theory of the 

 lonians. — Thus it is seen that as early as the beginning of 

 Greek philosophy the Ionian school of physicists (Thales and 

 Anaximander) recognized the principle of change in nature. 

 Without the idea of change cause has little meaning, and 

 from a philosophical point of view modern science traces back 



* Introduction to " Histoire des animaux sans Vertebres," etc., published in 

 1815-1820. 



