414 BIOLOGY AND ITS MAKERS 



to speak, was Darwin's personal representative, regards 

 isolation as an indispensable factor to the strengthening of 

 variations and thus bringing about the changes that lead to 

 the evolution of species. 



The intensive scrutiny to which the different theories of 

 organic evolution have been subjected, has served to focalize 

 attention on various aspects of species forming. Natural 

 selection stands forth as the agency to direct the general 

 course of evolution after it is started, while as regards the be- 

 ginnings, there are other important questions as the causes 

 of variability, that await further investigation. 



The cause for the general confusion in the popular mind 

 regarding any distinction between organic evolution and 

 Darwinism is not far to seek. As has been shown, Lamarck 

 launched the doctrine of organic evolution, but his views did 

 not even get a public hearing. Then, after a period of tem- 

 porary disappearance, the doctrine of evolution emerged 

 again in 1859. And this time the discussion of the general 

 theory centered around Darwin's hypothesis of natural selec- 

 tion. It is quite natural, therefore, that people should think 

 that Darwinism and organic evolution are synonymous terms. 

 The distinction between the general theory and any particular 

 explanation of it has, I trust, been made sufficiently clear in 

 the preceding pages. 



