viii Introduction. 



that no one can read one of Darwin's elaborate 

 works on this subject, without admiring the 

 great amount of learning and industry displayed 

 in the marvellous array of facts collected from 

 every conceivable source, which are brought 

 forward to illustrate even the most trifling 

 point under discussion. 



The literature of the subject has now become 

 very extensive, and Darwin's views are accepted, 

 with more or less reservation, by nearly all 

 scientific men, as a key to the mysteries of 

 Nature. Among the supporters of Evolution 

 may be found men of every shade of opinion, 

 from Herbert Spencer, who asserts that Atheism, 

 Pantheism and Theism are all equally unten- 

 able, to St. George Mivart, who attempts to 

 show that the teachings of the Fathers of the 

 Church are in accordance with Evolution. 



But although the main principle of Evolution 

 is now conceded by most naturalists, there is a 

 great difference of opinion on matters of detail, 

 and the subject is evidently still in its infancy. 

 It must not be supposed that Darwin's views, 

 comprehensive and valuable as they are, are by 

 any means final ; and every general work on 

 Evolution attempts to develop the subject more 

 extensively, or to throw light on certain ques- 

 tions which still remain obscure. It is often as 



