1 82 An Examination of Weismannism. 



Similarly, it seems to me. whatever cogency there may be 

 in Weismann's objection to Darwin's theory on the score 

 that it must assume " an unknown controlling force in order 

 to marshal the molecules." is equally great as regards his 

 own. True, Weismann has a lot to say about the control 

 which nucleoplasm can exercise on cell-formation, and 

 germ-plasm on marshalling successive stages of ontogeny ; 

 but all that this amounts to is a re-statement of the facts. 

 Such a controlling force must be equally assumed by both 

 theories ; but in each alike there is an absence of any ghost 

 of an explanation. 



Again, whatever difficulty there may be in conceiving 

 the transition of somatic substance, mutatis mutandis there 

 must be an equal difficulty in conceiving the transition of 

 germinal substance into somatic substance. Indeed, as far 

 as I can see, the difficulty is even greater in the latter case 

 than it is in the former. For the very essence of Weismann's 

 view is that germ-plasm differs from all or any other 

 " plasm " in origin or kind : germ-plasm, and germ-plasm 

 alone, has been immortal, perpetually continuous, capable 

 of indefinite self-multiplication, and so of differentiating 

 itself into an endless number and variety of somatic tissues. 

 But, according to Darwin's view, there is not, and never 

 has been, any such fundamental difference between the 

 essential nature of somatic elements, and the essential 

 nature of sexual elements. On the contrary, it is supposed 

 that both formative and formed material are one in kind 



the distinction by alluding to the controversy between the preformation- 

 ists and epigenesists. But the theory of pangenesis does not suppose the 

 future organism to exist in the egg-cell as a miniature : it supposes 

 merely that every part of the future organism is represented in the egg- 

 cell by corresponding material particles. And this, as far as I can 

 understand, is exactly what the theory of germ-plasm supposes ; only 

 it calls the particles "molecules," and seemingly attaches more im- 

 portance to the matter of variations in their arrangement or " constitution," 

 whatever these vague expressions may be intended to signify. 



