DARWINISM ATTACKED. 87 



races are unstable; they revert ties) are stable; they do not 



easily to the ancestral type if revert if the outer conditions 



allowed to run wild; this is so (environment) remain constant; 



probably because of their recent this is so probably because they 



origin. are more firmly established by 



reason of greater age. 



(7) The artificially-produced (7) Natural varieties do not 



races of the same species are cross in nature, either with 



in most cases fertile among each other or with the ancestral 



themselves. type. 



The most important contrast between the two kinds of 

 selection lies, in my eyes at least, in the results obtained in 

 the character of the new forms. As Morgan 21 well says, 

 "we should not lose sight of the fact that even after the most 

 rigorous selective process has been brought to bear on 

 organisms, namely, by isolation under domestication, we do 

 not apparently find ourselves gradually approaching nearer 

 and nearer to the formation of new species, but we find, on 

 the contrary, that we have produced something quite differ- 

 ent. In the light of this truth, the relation between the two 

 selective theories may appear quite different from the inter- 

 pretation that Darwin gives of it. We may well doubt 

 whether nature does select so much better than does man, 

 and whether she has ever made new species in this way." 



De Vries expresses very positively his belief that no artifi- 

 cial races are fixed and constant forms, in the sense that 

 natural varieties are. And this difference he believes to rest 

 on the radically different method 23 of origin of the two 

 kinds of forms; the domestic ones through carefully main- 

 tained selection; the natural ones through definitive imme- 

 diately fixed and enduring mutations. 



If one stops to recall his own familiar knowledge of the 

 cultivated plants 23 and will roughly classify the cultivated 

 fruits and vegetables and ornamental plants with which he is 

 acquainted into two categories depending upon the mode of 

 reproduction, that is whether by division or by seeds, one 

 will be struck by the great preponderance of the first of the 



