164 An Examination of Weismannism. 



have done well had he taken a further step and 

 surrendered the theory in toto. 



Similarly, he has withdrawn his previous distinctions 

 between the unicellular and multicellular organisms. 

 The Protozoa and Protophyta are now included by 

 him in the same category as the Metazoa and Meta- 

 phyta. as regards all matters of individual variation, 

 reproduction, subjection to the law of natural selection, 

 and so forth. The only difference which he continues 

 to allege is the somewhat metaphysical one touching 

 mortality and immortality. But I have given what 

 appears to me sufficiently good reasons for ignoring 

 this distinction ; and therefore, as it seems to me, 

 every one of Weismann's previous doctrines respecting 

 unicellular organisms have vanished — very much to 

 the benefit of his system as a whole. 



By far the greatest change, however, which he has 

 made in this general system is that which he has 

 effected by surrendering the postulate of the absolute 

 stability of germ-plasm. The rift in his lute which 

 has been noticed with regard to this matter has 

 now been widened to an extent which docs prevent 

 any further harping on the theme of evolution. It 

 is true that Weismann endeavours to retain as far as 

 possible the general character of his former postulate 

 of the universal stability of germ-plasm, with the 

 consequent " significance of sexual reproduction " as 

 the sole cause of congenital variation. For although 

 he now reverses both these doctrines by saying that 

 germ-plasm is universally unstable, and that sexual 

 reproduction is in no case the sole cause of congenital 

 variation, he seeks at the same time to minimize the 

 logical consequences of such reversal by making ar 



