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 organic 

 beings inhabiting South Amdrica, and in the geological rela- 

 tions 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 bcei\ called by one of our great- 

 est pliiloso^ihcrs. On my return home, it occurred to me, in 

 1837, that something might perhaps be made out on this ques- 

 tion 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 : 

 fiom that period to the present day I have steachly pursued 

 tlie same object. I hope that I may be excused from 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 archi- 

 pelago, has arrived at almost exactly the same general conclu- 

 sions 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 Lycll, who sent it to the Linnean Society, and 



