2l6 THE METHOD OF DARWIN. 



in the " Origin of Species " : first, that species 

 are derived by modification from other species, 

 and, secondly, that Natural Selection is the 

 chief cause of this modification. He did not 

 originate the former; the logical relation of his 

 work to it is deductive, and largely took the 

 form of an answer to the question, Do the facts 

 of Nature harmonize with the hypothesis? 



The cause of the modification of species could 

 not even be raised as a question until the fact 

 of modification had been accepted, at least ten- 

 tatively. He recognized the cause of specific 

 modification as a problem to be solved, a prin- 

 ciple to be discovered by induction from the 

 effects it produced in the form of adaptations. 

 To quote his own words: "My first note-book 

 was opened in July, 1837. I worked on true 

 Baconian principles, and without any theory 

 collected facts on a wholesale scale, more 

 especially with respect to domesticated pro- 

 ductions," etc. 1 He had rejected Lamarck's 

 suggestions, and it would seem impossible to 

 imagine a more interesting or more purely 

 inductive problem than that which presented 

 itself to him. There was for him no clew to 

 the cause which he wished to discover except 

 in the vast wealth of material which he regarded 



i Life*nd Letters, Vol. I. p. 68. 



