2 DARWINISM TO-DAY. 



of biological investigation. Conspicuous among these new 

 kinds of work are the statistical or quantitative study of 

 variations and that most alluring work variously called 

 developmental mechanics, experimental morphology, ex- 

 perimental physiology of development, or, most suitably of 

 all because most comprehensively, experimental biology. 2 

 This work includes the controlled modification of conditions 

 attending development and behaviour, and the pedigreed 

 breeding of pure and hybrid generations. Now this combina- 

 tion of destructive critical activity and active constructive ex- 

 perimental investigation has plainly resulted, or is resulting, 

 in the distinct weakening or modifying of certain familiar 

 and long-entrenched theories concerning the causative factors 

 and the mechanism of organic evolution. Most conspicuous 

 among these theories now in the white light of scientific 

 scrutiny are those established by Darwin, and known, col- 

 lectively, to biologists, as Darwinism. 



To too many general readers Darwinism is synonymous 

 with organic evolution or the theory of descent. The word 



is not to be so used or considered. Darwinism, 

 wiStfis! 8 *" primarily, is a most ingenious, most plausible, 



and, according to one's belief, most effective or 

 most inadequate, causo-mechanical explanation of adaptation 

 and species-transforming. It is that factor which, ever since 

 its proposal by Darwin in 1859, has been held by a majority 

 of biologists to be the chief working agent in the descent, 

 that is, the origin, of species. However worthy Darwin is of 

 having his name applied directly to the great theory of 

 descent for it was only by Darwin's aid that this theory, 

 conceived and more or less clearly announced by numerous 

 pre-Darwinian naturalists and philosophers, came to general 

 and nearly immediate acceptance the fact is that the name 

 Darwinism has been pretty consistently applied by biologists 

 only to those theories practically original with Darwin which 

 offer a mechanical explanation of the accepted fact of 



