No. 507] DARWIN'S " ORIGIN OF SPECIES " 



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once see why their crossed offspring should follow the same complex 

 laws in their degrees and kinds of resemblance to their parents, . . . 

 as do the crossed offspring of acknowledged varieties. This similarity 

 would be a strange fact if species had been independently created and 

 varieties had been produced through secondary laws (p. 417). 



On the following pages, 418-419, he summarizes facts 

 such as the close resemblance between existing and ex- 

 tinct forms on the several continents, the inhabitants of 

 oceanic islands, on islands near continents, and closes 

 with this sentence: 



Such cases as the presence of peculiar species of bats on oceanic 

 islands and the absence of all other terrestrial mammals, are facts 

 utterly inexplicable on the theory of independent acts of creation. 



I make but one more quotation in this connection. 

 Near the end of the book, in a sentence which the careless 

 reader might understand to refer to something like the 

 modern mutation theory, he says : 



Under a scientific point of view, and as leading to further investiga- 

 tion, but little advantage is gained by believing that new forms are 

 suddenly developed in an inexplicable manner from old and widely 

 diff 'event forms, over the old belief in the creation of species from the 

 dust of the earth (p. 424). 



Such quotations could be multiplied many times, for 

 over and over again throughout the book he speaks of 

 his theory as standing for the mutability of species as 

 against the independent creation of species. Indeed, so 

 convincing to the world was Darwin's argument in sup- 

 port of his main thesis that the word Darwinism to the 

 popular mind stands for the theory of descent, as it is 

 perfectly right that it should do. 



II. A secondary thesis is an attempt to account for the 

 origin of species by the theory of descent with modifica- 

 tion through variation and natural selection. 



I shall now attempt to show by quotations : 



1. Darwin's view of the part played by fluctuating 

 variations. 



— The role of sudden variations. 



3. The part taken by natural selection. 



1- The following quotations would prove a narrow and 



