ORIGIN OF SPECIES. 



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 bear- 

 ing 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 s^w 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 worlc 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 



