1 86 THE MUTATION THEORY 



stand, appeals that we shall vigorously prosecute the experimental 

 method and abstain from controversy mean little more than that 

 we shall ignore all material gathered otherwise than by experiment, 

 and abstain from testing the correctness of guesses that we shall 

 permit biology to become a tumbling-ground for irresponsible 

 whimsies. Declarations that the time is not ripe for the discussion 

 of the origin of species, and that the manner and causation of 

 adapted differentiation are still wholly mysterious, imply nothing 

 more than that it has been found impossible to bring the Mendelian 

 and mutation hypotheses into accord with the fact that living beings 

 exist and are fitted to their surroundings. The denial (based on 

 the supposed inutility of structures, the uses of which have not 

 been ascertained) that living beings are, in a wonderfully complete 

 degree, adaptational forms, has precisely the same origin. 



