PREFACE 



As already stated in the Preface to the second 

 edition of Darwin and after Darwin, Part I, severe 

 and protracted illness has hitherto prevented me from 

 proceeding to the publication of Part II. It is now 

 more than a year since I had to suspend work of 

 every kind, and therefore, although at that time 

 Part II was almost ready for press, I have not yet been 

 able to write its concluding chapters. Shortly before 

 and during this interval Professor Weismann has 

 produced his essays on Amphimixis and The Germ- 

 plasm. These works present extensive additions to, 

 and considerable modifications of, his previous theories 

 as collected together in the English translation, under 

 the title Essays on Heredity, Vol. I. Consequently, 

 it has become necessary for me either to re-write the 

 examination of his system which I had prepared for 

 Part II of my own treatise, or else to leave that 

 examination as it stood, and to add a further chapter 

 dealing with those later developments of his system 

 to which I have just alluded. After due reflection 



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