PREFACE 



As its sub-title announces, the present volume is 

 mainly devoted to a consideration of those Post- 

 Darwinian Theories which involve fundamental 

 questions of Heredity and Utility. 



As regards Heredity, I have restricted the discussion 

 almost exclusively to Professor Weismanns views, 

 partly because he is at present by far the most im- 

 portant writer upon this subject, and partly because 

 his views with regard to it raise with most distinctness 

 the issue which lies at the base of all Post-Darwinian 

 speculation touching this subject -the issue as to the 

 inheritance or non-inheritance of acquired characters. 



My examination of the Utility question may well 

 seem to the general reader needlessly elaborate ; for 

 to such a reader it can scarcely fail to appear that 

 the doctrine which I am assailing has been broken 

 to fragments long before the criticism has drawn to 

 a close. But from my previous experience of the 

 hardness with which this fallacious doctrine dies, 

 I do not deem it safe to allow even one fragment of 

 it to remain, lest, hydra-like, it should re-develop into 



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