Z INTRODUCTION. 



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 to me 

 a memoir on this subject, with a request that I would 

 forward it to Sir Charles Lyell, who sent it to the Lin- 

 nean 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 work — the latter having 

 read my sketch of 1844 — honoured me by thinking it 

 advisable to publish, with Mr. Wallace's excellent me- 

 moir, some brief extracts from my manuscripts. 



This Abstract, which I now publish, must necessarily 

 be imperfect. I cannot here give references and autho- 

 rities for my several statements ; and I must trust to 

 the reader reposing some confidence in my accuracy. 

 No doubt errors will have crept in, though I hope I have 

 always been cautious in trusting to good authorities 

 alone. I can here give only the general conclusions at 

 which I have arrived, with a few facts in illustration, 

 but which, I hope, in most cases will suffice. No one 

 can feel more sensible than I do of the necessity of here- 

 after publishing in detail all the facts, with references, 

 on which my conclusions have been grounded ; and I 

 hope in a future work to do this. For I am well aware 

 that scarcely a single point is discussed in this volume 

 on which facts cannot be adduced, often apparently 

 leading to conclusions directly opposite to those at which 

 I have arrived. A fair result can be obtained only by 

 fully stating and balancing the facts and arguments on 

 both sides of each question ; and this cannot possibly be 

 here done. 



I much regret that want of space prevents my having 

 the satisfaction of acknowledging the generous assistance 

 which I have received from very many naturalists, some 

 of them personally unknown to me. I cannot, however, 



