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 America, and in the geological rela- 

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

 nent. 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 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 (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. Wal- 

 lace, 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, 



I 



