Weismanris theory of Heredity (1891). 63 



other words, by supposing that stirp was exactly 

 the same as what was afterwards called germ-plasm, 

 in that it always occupied a separate "sphere" of 

 its own, where its continuity has been uninterrupted 

 " since the first origin of life." But Galton was not 

 seduced by the temptation to construct an ideally 

 logical system ; and he had what I regard as the 

 sound judgement to abstain from carrying his theory 

 of stirp into any such transcendental "sphere" as that 

 which is occupied by Weismann's theory of germ- 

 plasm, in relation to the general doctrine of descent. 



There is, then, a vast distinction between any 

 theory of heredity which postulates the material of 

 heredity as highly stable and largely continuous, and 

 Weismann's theory, which postulates this material as 

 absolutely stable and perpetually continuous. But 

 we must next take notice that Weismann himself has 

 not kept this distinction in view with the constancy 

 which we should have expected from so forcible 

 a thinker. On the contrary, although in the con- 

 struction of his theory of evolution he never fails 

 to press the postulates of absolute stability and per- 

 petual continuity to their logical- conclusions in the 

 various doctrines above enumerated (pp. 57-58), when 

 engaged on his more special theory of heredity he 

 every now and then appears to lose sight of the 

 distinction. Indeed, he occasionally makes such large 

 concessions with regard to both these postulates, 

 that, were they to be entertained, the occupation of 

 his critics would be gone : his theory of heredity 

 would become converted into Galton's, while his 

 theory of evolution would vanish altogether. It is 



