ORIGIN OF SPECIES. 



IKTEODUOTION. 



When on board H. M. S. Beagle, as naturalist, I was 

 much struck with certain facts in the distribution of 

 the organic beings inhabiting South America, and in tlie 

 geological relations of the present to the past inhabitants 

 of that continent. These facts, as will be seen in the latter 

 chapters of this volume, seemed to throw some light on the 

 origin of species— that mystery of mysteries, as it has been 

 called by one of our greatest philosophers. On my return 

 home, it occurred to me, in 1837, that something might 

 perhaps be made out on this question by patiently accumu- 

 lating and reflecting on all sorts of facts which could possi- 

 bly have any bearing on it. After five years' work I 

 allowed myself to speculate on the subject, and drew up 

 some short notes; these I enlarged in 1844 into a sketch of 

 the conclusions, which then seemed to me probable: from 

 that period to the present day I have steadily pursued the 

 same object. I hope that I may be excused for entering 

 on these personal details, as I give them to show that I 

 have not been hasty in coming to a decision. 



My work is now (1859) nearly finished; but as it will 

 take me many more years to complete it, and as my health 

 is far from strong, I have been urged to publish this ab- 

 stract. I have more especially been induced to do this, as 

 Mr. Wallace, who is now studying the natural history of 

 the Malay Archipelago, has arrived at almost exactly the 

 same general conclusions that I have on the origin of 

 species. In 1858 he sent me a memoir on this subject, 

 with a request that I would forward it to Sir Charles Lyell, 

 who sent it to the Linnean Society, and it is published in the 

 third volume of the Journal of that Society. Sir 0. Lyell 



