The Discovery of Natural Selection 



From the date of the above letter (1847) on to the early 

 part of 1855 — nearly eight years later — no reference is found 

 either in his Life or correspondence to the one absorbing 

 idea towards which all his reflective powers were being 

 directed. Then, during a quiet time at Sarawak, the 

 accumulation of thought and observation found expres- 

 sion in an essay entitled ^' The Law which has regulated 

 the Introduction of Species,'' which appeared in the 

 Annals and Magazine of Natural History in the following 

 September (1855). 



From November, 1854, the year of his arrival in the East, 

 until January or February, 1856, Sarawalv was the centre 

 from which Wallace made his explorations inland, includ- 

 ing some adventurous excursions on the Sadong River. 

 During the wet season — or spring — of 1855, while living 

 in a small house at the foot of the Santubong Mountains 

 (with one Malay boy who acted as cook and general com- 

 panion), he tells us how he occupied his time in looking 

 over his books and pondering " over the problem which 

 was rarely absent from [his] thoughts." In addition to 

 the knowledge he had acquired from reading such books 

 as those by Swainson and Humboldt, also Lucien Bona- 

 parte's '' Conspectus," and several catalogues of insects 

 and reptiles in the British Museum '' giving a mass of 

 facts " as to the distribution of animals over tlie whole 

 world, and having by his own efforts accumulated a vast 

 store of information and facts direct from nature while in 

 South America and since coming out East, he arrived at 

 the conclusion that this ^^ mass of facts " had never been 

 properly utilised as an indication of the way in which 

 species had come into existence. Having no fellow-traveller 

 to whom he could confide these conclusions, he was almost 

 driven to put his thoughts and ideas on paper — weighing 

 each argument with studious care and open-eyed considera- 



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