THE EVOLUTION OF LIVING BEINGS. 33 



Linneon e. g. a group of morphologically similar, but 

 constitutionally, different individuals. 



That this is really the case has been shown admirably 

 by Heribert Nilsson who proved among other things, 

 that individuals of the Linneon Oenethera Lamarckia- 

 na produce, after self fertilisation, different „mutants" 

 and in different proportions, from which he draws the 

 only warranted conclusion that different individuals of 

 O. Lamarckiana have different constitutions. 



The fact is not challenged by de Vries, but he takes 

 — indirectly — exception as to the conclusion. 



So he says on p. 340 of his Gruppenweise Artbildung : 



„Die Mutabihtat einer reinen Rasse ist keineswegs 

 stets dieselbe ; die Emte der einen Mutter ist oft viel 

 reicher an Mutanten als diejenige einer Nachbarin". 



Or in engUsh: 



„The mutabiUty of a pure Race is by no means al- 

 „ways the same : the crop of one mother is frequently 

 „much richer in mutants than the one of a neighbour." 



We naturally expect to find conclusive evidence for 

 the legitimacy of this startling assertion in the results 

 of new experiments with a race, the purity of which was 

 beyond all reasonable doubt. 



Unf ortimately this is not the case ; de Vries bases this 

 assertion solely upon a creed, and on nothing but a 

 creed: the supposed specific purity of O. Lamarckiana. 



It is useless to fight against dogmatic creeds; where 

 they lead to, the sentences^ following immediately upon 

 the one quoted above, show: 



„Von Oenothera scintiUans, welche gewohnlich aus 

 „ihren Samen van 15 — ^40% scintillans Pflanzen er- 



