EDITOR'S PREFACE 



THE publication of Darwin's Origin of Species 

 worked one of those revolutions in popular thought 

 which occur only at very rare intervals. Up to 1859 

 both the naturalist to use a word more common 

 then than now and the generally well-informed 

 man were usually content to accept the fact that 

 different species of animals and plants existed, 

 without troubling themselves as to how these 

 different species came to be. After that date, and 

 so soon as Darwin's ideas triumphed, as they 

 speedily did, over all opposition, the doctrine of 

 evolution was accepted by every one, and, on 

 its elaboration by Herbert Spencer, came to be 

 recognized as one of the most widely spread of all 

 the laws of nature. Yet the very completeness of 

 the revolution blinded us to many of the points of 

 this doctrine. There were evolutionists before 

 Darwin, and some of these Lamarck, for instance 

 had gone even further than he in their researches 

 into the modification of animal forms by their en- 



