34 THE EVOLUTION OF LIVING BEINGS. 



,,zeugt, habe ich einmal eine Rasse gehabt, welche 

 ,,deren 66 93%, im mitt el 84%, hervorbrachtte". 



And this, to support the assertion that the mutability 

 of different individuals of a pure race can be different ! 



On the question : how do you prove that different in- 

 dividuals of a pure race can be of different mutability ? 

 one thus obtains the answer : well do'nt you see ? I had 

 once a group of races (O. scintillans) in which indivi- 

 duals belonging to different races, l ) behaved diffe- 

 rently ! 



And this is not a slip of the pen on de Vries part! 



In a very recent article (Bot. Gazette Nov. 1915) he 

 says on p. 341: 



,,In order to obtain species of O. gigas yielding a high 

 ,,percentage of dwarfs from their seeds, I sowed in 1911 

 ,,seeds of my pure strain 2 )", cultivated as biennials, and 

 ,,fertilised them 1912 by their own pollen in bags". 



The result was an of fspring,consisting of plants which 

 threw no dwarfs, others which threw 0,6% of dwarfs, 

 others which threw 1.5% of dwarfs, others again which 

 threw 2.3% of dwarfs, yes even plants which threw 

 17.8% of dwarfs! Yet de Vries refuses to entertain the 

 idea that his O. gigas might have been impure! 



Nor causes the fact 3 ), that the cross O. Lamarckia- 

 na x O. nanella gives a heterogenous F a generation, con- 



J ) Von O. scintillans, welche gewohnlich von 15 40% scintillans 

 erzeugt, habe ich friiher einmal eine Rasse gehabt, welche deren .... 

 im mittel 84% hervorbrachtte. 



2 ) The italics are mine. 



3 ) Hugo de Vries: Ueber amphikline Bastarde. Berichte Deutsch 

 botanische Gesellschaft November 1915. 



