Critical Considerations 67 



Hanstein, with good reason, first rejects the name 

 gemmule, and calls the Darwinian units mikroplasts, or 

 archiplasts. And since he denies the transmission hy- 

 pothesis, he concludes from pangenesis :^^ ''One ought even 

 to make the hypothesis, that every cell of the entire plant- 

 body, at its very origin, is endowed by its mother-cells 

 with every kind of archiplast."*^ The correctness of this 

 conclusion will probably now be admitted by all readers as 

 a necessary consequence of the assumption of archiplasts, 

 as these are indeed transmitted from one generation to the 

 other in the egg- and sperm-cells.'*^ 



Hanstein's objections I may here pass over. They 

 are based chiefly on his conviction that it is unavoidable 

 to assume a special power of nature for organisms.*^ 



Weismann, in his work on heredity (1883. p. 16), 

 has expressed himself against the assumption of different 

 bearers of the individual hereditary characters. Accord- 

 ing to him, this conception does not show how these 

 ''molecules" are to stay together in exactly those combi- 

 nations in which they exist in the germ-plasm of the 

 respective species. Without doubt this is the main diffi- 

 culty, and the fact that it has been the most important 

 cause of the establishment of the theories discussed in 

 the preceding chapter, shows what weight it carries. 



But this difficulty is no objection. It is true that it 

 cannot be explained how the individual pangens may be 

 held together. But the more recent investigations on nu- 

 clear division have given us an insight into extremely 

 complicated processes, the object of which is evidently an 



^^Loc. cit. p. 219. 

 ^^Loc. cit. p. 223. 

 *iLoc. cit. p. 219. 

 ^^Loc. cit. p. 225. 



