vl Preface. 



its former proportions. And 1 can scarcely think 

 that naturalists who know the growing prevalence 

 of the doctrine, and who may have followed the issues 

 of previous discussions with regard to it, will accuse 

 me of being more over-zealous in my attempt to make 

 a full end thereof. 



One more remark. It is a misfortune attending 

 the aim and scope of Part II that they bring me 

 into frequent discord with one or other of the most 

 eminent of Post-Darwinian writers — especially with 

 Mr. Wallace. But such is the case only because 

 the subject-matter of this volume is avowedly re- 

 stricted to debateable topics, and because I choose 

 those naturalists who are deservedly held in most 

 esteem to act spokesmen on behalf of such Post- 

 Darwinian views as appear to me doubtful or erro- 

 neous. Obviously, however, differences of opinion 

 on particular points ought not to be taken as imply- 

 ing any failure on my part to recognize the general 

 scientific authority of these men, or any inability 

 to appreciate their labours in the varied fields of 

 Biology. 



G. J. R. 



Christ Church, Oxford. 



