34 THE EVOLUTION OF LIVING BEINGS. 



„zeugt, habe ich einmal eine Rasse gehabt, welche 

 „deren 66 — 93%, im mittel 84%, hervorbrachtte". 



Andthis,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 mutabiUty ? 

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

 once a grou/p of races (O. scintillans) in which indivi- 

 duals belonging to different races, ^) 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 oimypure strain ^)", cultivated as biennials, and 

 „fertihsed them 1912 by their own pollen in bags". 



The result was an offspring.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 »), that the cross O. Lamarckia- 

 na X O. nanella gives a heterogenous Fi generation, con- 



^) Von O. scintillans, welche gewdhnlich von 15 — 40% scintillans 



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



im mittel 84% hervorbrachtte. 



*) The italics are mine. 



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

 botanische GeseUschaft November 1915. 



