THE STORY OF NINETEENTH-CENTURY SCIENCE 



mind was open and receptive; he was eager only for 

 facts which might lead him to an understanding of a 



CHARLES ROBERT DARWIN 



problem which seemed utterly obscure. It was some- 

 thing to feel sure that species have varied ; but how 

 have such variations been brought about? 



It was not long before Darwin found a clew which he 

 thought might lead to the answer he sought. In cast- 

 ing about for facts he had soon discovered that the 



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