No. 519] THE EFFECTIVENESS OF SELECTION 137 



Not the faintest tract* of effect is produced, even by long- 

 continued methodical selection for hundreds of genera- 

 tions. The race or line is absolutely permanent, so far 

 as the appearance of any hereditary differences are con- 

 cerned. The individuals of the line do indeed differ 

 greatly among themselves, but these differences are not 

 inherited; they furnish absolutely no foothold for selec- 

 tion. 



Examination showed that Paramecium consists of 

 many such races, differing among themselves slightly, 

 but each race as unyielding as iron. And the extreme 

 i;aces found in the wild culture are precisely the extremes 

 obtainable by long-continued selection. 



The effects of selection have then consisted simply and 

 solely in isolating races that already existed. It had 

 produced nothing new; there had been no progress that 

 would form a step, however slight, in the journey from 

 Amoeba to man. 



When [ had reached this point I looked about and 

 found that others had been having similar experiences. 

 The investigator who discovers these things for himself 

 finds perhaps that 



Dock bleibt sie immer neu. 



And the second line is as true as the first, for to one 

 who has put months and years on such attempts to accom- 

 plish results by methodical selection, its utter powerless- 

 ness comes with new and surprising force. Johannsen 

 in working with beans and barley, Hanel with Hydra, 

 had found many pure lines existing in nature, but as in 

 my own case, each pure line was absolutely unyielding. 



