408 FOUNDATIONS OF BIOLOGY 



tion of the factors of geographical isolation, struggle for 

 existence, artificial and natural selection in the origin of 

 species, but also the propounding of a theory of the origin 

 of variations that the direct action of the environment 

 brings about alterations in the structure of animals and 

 plants and these are transmitted to the offspring. 



When Buffon's influence had passed its zenith, ERASMUS 

 DARWIN (1731-1802) expressed consistent views on the 



FIG. 210. Erasmus Darwin. 



evolution of organisms, in several volumes of prose and poetry, 

 which lead biologists to-day to recognize him as the antici- 

 pator of the Lamarckian doctrine that somatic variations 

 arise through the reaction of the organism to environmental 

 conditions. " All animals undergo transformations which are 

 in part by their own exertions, in response to pleasures, and 

 pain, and many of these acquired forms or propensities are 

 transmitted to their posterity." 



