INTRODUCTION 



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

 with certain facts in the distribution of the organic beings in- 

 habiting South America, and in the 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 accumulating 

 and reflecting on all sorts of facts which could possibly have any 

 bearing on it. After five years' work I allowed myself to specu- 

 late 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 Abstract. 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 C. Lyell and Dr. 

 Hooker, who both knew of my work— the latter having read my 

 sketch of 1844 — honoured me by thinking it advisable to publish, 

 with Mr. Wallace's excellent memoir, some brief extracts from 

 my manuscripts. 



This Abstract, which I now publish, must necessarily be im- 

 perfect. I cannot here give references and authorities for my 

 several statements ; and I must trust to the reader reposing some 

 confidence in my accuracy. No doubt errors will have crept in. 

 though I hope I have always been cautious in trusting to good 



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