THE EVOLUTION OF LIVING BEINGS. 35 



sisting of Lamarckianas and nanellas in different nu- 

 mericalproportions,dependingonthe,,individuelleKraft 

 derSamentrager" (euphemism for : different genotypical 

 constitution), de Vries any uneasiness as to the justifia- 

 bility of considering his Lamarckiana as pure ; far from 

 doubting the purity of his strain, he concludes unblus- 

 hingly from some rather rough experiments, that ,,die 

 Kreuzung van O. Lamarckiana mit O. Lam. mut. na- 

 nella (sic) liefert, je nach den Kulturbedingungen, 

 o 90% Zwerge ! 



The question of the specific purity of O. Lamarckia- 

 na, the basis of de Vries' assertions, is not, as it ought to 

 be to him, an object worthy of the most scrupulous 

 investigation, but a dogmatic creed. 



This involves of course the belief in the existence of 

 mutations thrown by O. Lamarckiana ; we can not de- 

 ny the possiblity that mutations may exist, but as 

 scientists, we cannot be satisfied with a mere belief ; we 

 want proof, especially where it concerns such an entire- 

 ly novel thing, as the real existence of the, so far only 

 surmised, existence of mutations would be. 



The behaviour of O. Lamarckiana gives us not the 

 slightest cause to suppose that the aberrant forms, 

 thrown by it, owe their origin to a process of mutation; 

 they can perfectly well be explained, without ressor- 

 ting to an explanation", lying outside of the pale of 

 experience, by the simple fact which the experiments 

 which have been published all tend to show, viz. thatO. 

 Lamarckiana is a mixture of heterozygotes of different 

 constitutions throwing rogues (the pretended mutants) 

 by a process of mendelian segregation, in proportions, 



