58 An Examination of Weismannism. 



also, the multicellular organisms are ultimately depen- 

 dent upon this absolute stability of their germ-plasm 

 for all the progress which they have made in the 

 past, as well as for any progress which they may be 

 destined to make in the future. 



Thus we see that the two points of difference 

 between germ-plasm and gemmules are not merely 

 of great importance as regards the particular problem 

 which is presented by the phenomena of heredity : 

 they are of still greater importance as regards 

 the general theory of evolution. For if these two 

 qualities of perpetual continuity and absolute sta- 

 bility can be proved to belong to the material basis 

 of heredity, the entire theory of evolution will have 

 to be reconstructed from its very foundation — and 

 this quite apart from the more special question as 

 to the transmission of acquired characters. There- 

 fore we shall presently have to consider these two 

 alleged qualities with the care that they demand, as 

 having been seriously suggested by so eminent a 

 naturalist as Professor Weismann. But. before pro- 

 ceeding to do so, I must briefly compare his theory 

 with that of Mr. Galton. 



"Stirp" resembles both "germ-plasm" and "gem- 

 mules " in all the respects which have above been 

 named as common to the two latter. But it differs 

 from gemmules and further resembles germ-plasm 

 in all the following particulars. It is derived from 

 the stirp of proceeding generations, and constitutes 

 the sole basis of heredity. Only a part of it. however, 

 is consumed in each ontogeny — the residue being 

 handed over to "contribute to form the stirps of 

 the offspring." where it undergoes self-multiplication 



