From Observation to Experimentation 287 



all who were acquainted with the facts. The instant suc- 

 cess of Darwin's theory among scientists reopened the older 

 issues upon which Saint-Hilaire and Cuvier had debated, 

 namely, whether species were fixed from the time of crea- 

 tion or whether transmutation does in fact take place. In 

 the heat of controversy it naturally came about that the 

 general question was confused with the special theory, and 

 the disentanglement of the two is far from complete even 

 among scholars and educated laymen. 



FroTn Observation to Experivtentation 



The rise of Darwinism as a plausible explanation of 

 transformation stimulated research in every direction, much 

 of it deliberately designed to support or illustrate the doc- 

 trine of natural selection. An increased amount, however, 

 was deliberately planned to find more and more funda- 

 mental facts. 



As we all know, the physical sciences were making rapid 

 progress during this period through the elaboration of 

 experimental methods of research. Gradually the biolo- 

 gists took over more and more of the experimental method. 

 By the end of the Nineteenth Century it was possible 

 to attack by means of experiment the many special 

 questions raised by the discussion of evolution and natural 

 selection. 



This is not to say that experiments had not been con- 

 ducted before 1900, but only that at the present time ex- 

 perimentation is found to be feasible in the biological 

 sciences and is generally accepted as furnishing the ultimate 

 tests for any theory. As we have already seen, the Catholic 

 priest, Gregor Mendel, selected the problem of heredity as 

 the crucial one in the evolution of organic forms, which, 

 like his patron saint, he accepted as a matter of course; and 

 he devised experimental methods for clarifying this process. 

 This experimental attack did not influence the course of 

 study and discussion since the results were shelved in the 



