ON THE OEIGIN OF SPECIES 



INTRODUCTION 



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

 much struck with certain facts in the distribution of 

 the inhabitants of South America, and in the geological 

 relations of the present to the past inhabitants of that 

 continent. These facts seemed to me 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 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 nearly finished ; but as it will take 

 me two or three 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. Last year he sent me a 



B 



