appears to be wholly a matter of what we are pleased to 

 call chance. As has been said, De Vries obtained more 

 than a dozen different forms. Some of the mutants, we 

 may say, are probably destined to failure, others perhaps 

 are better placed, at least in new environment, than the 

 parental type and might conceivably stamp rt out in time. 

 What the criteria of success or non-success may be is a 

 matter upon which no one would care to give an opinion, 

 but I have in mind the fact that one of the mutants of 

 Lamarck's evening primrose has a tendency to germi- 

 nate somewhat more quickly than the parent form, and 

 the seedling grows a little more rapidly; it is conceivable 

 that some slight advantage of this sort might be the cru- 

 cial point. However that may be, it is here that we can 

 apply the Darwinian concept of the struggle for exist- 

 ence, a struggle however not between single individuals, 

 as the idea of continuous variation would imply, but the 

 struggle between great numbers of individuals, whole 

 groups of elementary species. The great contrast be- 

 tween Darwin and De Vries is the contrast between the 

 slow and continuous accretion of variations implied by the 

 former and the sudden jumping or saltatory variation in- 

 sisted on by the latter. By such means as De Vries main- 

 tains the process of evolution might take place with far 

 greater rapidity than by Darwin's method, for, generous 

 as the geologists are in their allowance of time for the 

 development of organic life on the world, it has always 

 been difficult of conception how even the countless ages 

 granted could compass the enormous development of the 

 highest organic types from simple forms. To maintain 

 that De Vries' theory is entirely complete, and must be 

 the only means of the origin of new forms, is unneces- 

 *sary. None but the extremist would go to such a 

 length; it is not at all necessary to assume that the 

 means to a similar end must necessarily be similar. 



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