OUTSTANDING BIOLOGICAL ADVANCES 23 



Species. The French zoologist, Lamarck (1744- 

 1829) was the first to announce, in 1801, a compre- 

 hensive theory of evolution that has lasted to the 

 present, while Darwin's especial contribution was 

 the designation of natural selection as the chief 

 agency in bringing about the evolution of animals and 

 plants. Besides these two, the theories of Weismann 

 and De Vries have attracted the most attention. 



This doctrine is so important and so intricate that 

 in a later chapter it will be returned to for fuller ex- 

 position of the different theories. 





