ORIGIN OF SPECIES 211 



when the question of descent takes the form of inquiry 

 into the causes and factors of heredity and variation, 

 those best informed — after a half -century of Darwin- 

 ism — profess only ignorance. 



The utter unsatisfactoriness of the general situa- 

 tion in evolutionary inquiry appears in especially 

 strong light when the indefiniteness and vagueness 

 of it all is compared with the definiteness and exact- 

 ness of the work done in chemistry and physics. That 

 life-processes are characterized by the same precision 

 of relations that always obtains in chemistry and 

 physics is clearly indicated by specific lines of experi- 

 mental research in botany and biology — cytology, 

 heredity-investigations of the kind inaugurated by 

 Mendel, and pursued by Raymond Pearl, Thomas 

 Hunt Morgan and others, and experiments on arti- 

 ficial parthenogenesis (J. Loeb's and others'). 

 To quote Bateson again: 



"As to almost all the essential features, 

 whether of cause or mode, by which specific 

 diversity has become what we perceive it to be, 

 we have to confess an ignorance nearly total. 

 .... When .... we contemplate the problem 

 of evolution at large, the hope at the present time 

 of constructing even a mental picture of that 

 process grows weak almost to the point of vanish- 

 ing. We are left wondering that so lately men 



