Weismannism up to date (1893). 163 



possible range, the instability of a universally unstable 

 germ-plasm — distributed, as this most complex of 

 known substances is, throughout all species of plants 

 and animals, and exposed to inconceivably varied 

 conditions of life in all quarters of the globe. And 

 these considerations are surely of themselves enough 

 to dispose of the assumption as absurd, without again 

 rehearsing the facts of congenital variation which 

 definitely prove it to be false. 



Cone hi si on. 



For reasons stated at the commencement of this 

 chapter, I have restricted its subject-matter almost 

 exclusively to a consideration of the more fundamental 

 changes which Professor Weismann has wrought in 

 his general system of theories by the publication of 

 his most recent works. In other words, I have pur- 

 posely avoided considering those immensely elaborate 

 additions to his theory of heredity which constitute 

 by far the largest portion of his essays on Amphimixis 

 and The Germ-plasm, and which have for their object 

 an ideal construction of " the architecture of germ- 

 plasm." 



The fundamental changes to which allusion has 

 just been made are as follows. 



Professor Weismann has to a large extent abandoned 

 his theory of polar bodies, and in my opinion would 



M 2 



