ON THE 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 

 inhabitants of South America, and in the geological rela- 

 tions of the present to the past inhabitants of that con- 

 tinent. 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 Dearly 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 



B 



