234 DARWIN. 



geological sense. It was evident that such facts as these, as well 

 as many others, could only be explained on the supposition that 

 species gradually became modified ; and the subject haunted me. 

 But it was equally evident that neither the action of the surround- 

 ing conditions,' nor the will of the organisms - (especially in the 

 case of plants), could account for the innumerable cases in which 

 organisms of every kind are beautifully adapted to their habits of 

 life ; for instance, the woodpecker or the tree frog to climb trees, 

 or a seed for dispersal, by hooks or plumes. I had alwavs been 

 much struck by such adaptations ; and until these could be ex- 

 plained, it seemed to me almost useless to endeavour to prove by 

 indirect evidence that species have been modified." 



It was after his return in 1837 that Darwin 

 opened his first note-book for the collection of facts 

 which bore in any way on variation in animals and 

 plants under domestication and in Nature. He 

 says : " I worked on true Baconian principles, and 

 without any theory collected facts on a wholesale 

 scale, more especially with respect to domesticated 

 products, by printed inquiries, by conversation with 

 skilful breeders and gardeners, and by extensive 

 reading." This is the most deliberate and rigid 

 -\ instance of the application of the inductive method 

 ' '^.' which we have met with in our whole study of the 

 -v.. ' ^ contributors to the Evolution theory. Darwin soon 

 saw the force of Selection as the secret of man's 

 success in forming useful races of animals and 

 plants; and in October, 1838, while reading Mal- 

 thus on population, the idea of Selection in a state 

 of Nature first occurred to him as the result of the 



1 He here refers to Buffon's factor. 



2 He here refers to and misconceives Lamarck's factor. 



A- 



