DE VRIES ON 'FLUCTUATIONS' 263 



speaking of * individual variability *, he says on 

 pages 36 and 37 :' This [form of] variability has 

 been termed, fluctuating, gradual, continued, rever- 

 sible, limited, statistical, and individual. The latter 

 designation appears to be most widely spread in 

 the domain of zoology and anthropology, whilst 

 the term fluctuating or flowing which was 

 frequently used by Darwin, ought certainly to be 

 the best.' That regression, only evident through 

 heredity, is characteristic of fluctuations, is stated 

 on p. 38: 'Individual variability is, by propaga- 

 tion [literally by sowing], revertent into itself.' 

 Again, on pages 38 and 39 : 



' Auf dem Gebiete der individuellen Variabilitat fiihrt die 

 Selection zu der Entstehung der Rassen. Dabei ist aber, wie 

 wir bereits gesehen haben, dieses letztere Wort in einem 

 anderen Sinne gebrauchlich, als in der Anthropologie. 1 

 Die principielle Differenz dieser sogenannten veredelten 

 Rasse einerseits mit Varietaten, Unterarten, elementaren 



letter, criticizing the hypothesis of the direct influence ot environ- 

 ment as a motive cause of evolution : 



' In ' regard to thorns and spines I suppose that stunted and 

 [illegible] hardened processes were primarily left by the abortion 

 of various appendages, but I must believe that their extreme 

 sharpness and hardness is the result of fluctuating variability and 

 the " survival of the fittest ".' In a letter to G. H. Lewes, Aug. 7, 

 1868. More Letters, i. 308. 



1 De Vries is here referring to p. 29, where he distinguishes the 

 two kinds of races as follows. It will be seen that the hereditary 

 transmission of fluctuations selected by the breeder is even more 

 clearly expressed than in the passage quoted in the text: 



' Aber das Wort Rassen hat bekanntlich eine doppelte Bedeutung. 

 Es bedeutet sowohl die durch Selection veredelten Rassen unserer 

 Ziichter, als auch die vorhandenen, constanten Unterarten unbe- 

 kannter Abstammung.' 



1 [' But the word races has, as we all know, a double meaning. It 

 signifies races improved by the selection of our breeders as well as 

 existing, constant sub-species of unknown origin.'] 



