The Discovery of Natural Selection 



of the other islands and of South America, the nearest con- 

 tinent. These facts suggested evolution, and without evolu- 

 tion appeared to be meaningless. 



Evolution and its motive cause were the problems 

 which ** haunted '' him for the next twenty years. The 

 first step towards a possible solution was the ^^ opening of 

 a notebook for facts in relation to the origin of species " 

 in 1837, two years before the publication of his Journal. 

 From the very commencement of his literary and scientific 

 work, a rule rigidly adhered to was that of interspersing 

 his main line of thought and research by reading books 

 touching on widely diverging subjects ; and it was thus, 

 no doubt, that during October, 1838, he read *^ for amuse- 

 ment " Malthus's *^ Essay on Population '' ; not, as he 

 himself af&rms, with any definite idea as to its intimate 

 bearing on the subject so near his heart. But the imme- 

 diate result was that the idea of Natural Selection at once 

 arose in his mind, and, in his own words, he '^ had a theory 

 by which to work.^' 



In May and June, 1842, during a visit to Maer and 

 Shrewsbury, he wrote his first ^^ pencil sketch of Species 

 theory,'' but not until two years later (1844) did he ven- 

 ture to enlarge this to one of 230 folio pages, ^* a wonder- 

 fully complete presentation of the arguments familiar to 

 us in the ' Origin.' "^ 



Already, in addition to the mass of facts collected, Darwin 

 was busy with some of the experiments which he described in 

 a letter to Sir Joseph Hooker (in 1855) as affording the latter 

 a ^* good right to sneer, for they are so absurd^ even in my 

 opinion, that I dare not tell you." While a sentence in 

 another letter (dated 1849) throws a sidelight on all this 

 preparatory work : *^ In your letter you wonder what 

 ^ ornamental poultry ' has to do with barnacles ; but do 



1 " Life of Charles Darwin" (one-vol. Edit.), p. 171. 

 103 



