declared the writer of a celebrated article in the North 

 British Review, is as follows: "AH these things may have 

 been, therefore my theory is possible; and since my theory 

 is a possible one, all those hypotheses which it requires are 

 rendered probable." 



3. We pass now to the question of the possibility of 

 building up a new species by the accumulation of chance 

 individual variations. That species ever originate in this 

 way is denied by the advocates of the evolutionary theory 

 which is now superseding Darwinism. Typical of the new 

 school is the botanist Hugo De Vries of Amsterdam. 

 The "first-steps" in the origin of new species according to 

 De Vries are not fluctuating individual variations, but mu- 

 tations, i. e., definite and permanent modifications. Ac- 

 cording to the mutation theory a new species arises from 

 the parent species, not gradually but suddenly. It appears 

 suddenly "without visible preparation and without transi- 

 tional steps." The wide acceptance with which this theory 

 is meeting must be attributed to the fact that men of science 

 no longer believe in the origin of species by the accumu- 

 lation of slight fluctuating modifications. To quote the 

 words of De Vries, "Fluctuating variation cannot overstep 

 the limits of the species, even after the most prolonged 

 selection — still less can it lead to the production of new, 

 permanent characters." It has been the wont of Darwin- 

 ians to base their speculations on the assumption that "an 

 inconceivably long time" could effect almost anything in 

 the matter of specific transformations. But the evidence 

 which has been amassed during the past forty yeas leaves 



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