Weismannism tip to date (1893). 137 



geny is a theory of struggle ; and this constitutes 

 a point of difference on which Weismann lays much 

 stress in his latest work. For, as we know, Weismann 

 regards the mechanism of ontogeny as characterized 

 by a peaceful succession of " stages," which are " pre- 

 determined from the germ onwards "; and in his latest 

 work this idea of orderly sequence has been further 

 elaborated in his doctrine of ''determinants." In 

 short, to adopt their own metaphors, while Galton 

 tells us that the mechanism of ontogeny is like that 

 of a political election, where rival candidates compete 

 to " represent " the nation (stirp) in Parliament (indi- 

 vidual organism) ; Weismann likens it to the mechan- 

 ism of a well-drilled army, where ultimate carriers 

 of heredity (privates) are banded together in com- 

 panies, regiments, battalions, &c, under the command 

 of corresponding officers (determinants). 



Lastly, there is yet one further point of difference 

 between stirp and germ-plasm, which is thus stated 

 by Weismann : — 



Galton's idea is only conceivable on the presupposition of the 

 occurrence of sexual reproduction, while the theory of the 

 continuity of the germ-plasm is entirely independent of any 

 assumption as to whether each primary constituent is present in 

 the germ singly or in numbers. According to my idea, the 

 active and the reserve germ-plasm contain precisely similar 

 primary constituents, gemmules, or determinants ; and on this 

 the resemblance of a child to its parent depends. The theory 

 of the continuity of the germ-plasm, as I understand it, is not 

 based on the fact that each "gemmule" necessary for the con- 

 struction of the soma is present many times only, so that a residue 

 remains from which the germ-cells of the next generation maybe 

 formed : it is founded on the view of the existence of a special 

 adaptation, which is inevitable in the case of multicellular organ- 

 isms, and which consists in the germ-plasm of the fertilized 



