THE METHOD 89 



proved by Haeckle, Spencer, Gegenbauer, or Kolliker, 

 all, very able naturalists. 



THE WORK OP HUGO DE VRIES. Hugo De Vries, of 

 Amsterdam, contends that species are formed by varia- 

 tion and heredity, but that the process is not a slow 

 adaption of minute variations. He contends that the 

 species is constituted by the required variation from the 

 parent stock at once. This, Darwin recognized as a 

 "sport." Whether this is true or not, in all instances, 

 it does not invalidate the principle of evolution, by the 

 survival of the fittest, in the struggle for existence. The 

 theory of De Vries simply shortens the process of the 

 same essential facts of Darwin's theory in certain 

 domestic classes of primroses. Some writers have as- 

 serted that De Vries undermined Darwin's theory. The 

 following extracts will disprove those assertions. 



De Vries says: "Those individuals survive that 

 find their life conditions most favorable, and they are 

 therefore the most vigorous. Natural selection, in the 

 struggle for existence, between the newly originated 

 elementary species is quite different. These originate 

 suddenly, unmediated, and multiply themselves, if 

 nothing stands in the way, because they are, for the 

 most part completely, or in a high degree heritable. 

 If then the increase leads to a struggle for sustenance, 

 the weaker succumb and are rooted out." 



"I do not pretend that the production of horticul- 

 ture novelties is the prototype of the origin of new 

 species in nature. I assume that they are, as a rule, 

 derived from the parent species, by the loss of some 

 organ or quality, whereas the main lines of the evolu- 

 tion of the animal and vegetable kingdom are, of 

 course, determined by progressive changes." This is a 

 very significant admission of De Vries. It means that 



