404 Weismanns Theories — 



According to him the germ-plasm has but one power and 

 function, the exact reproduction of the form from whence it 

 came. The germ-plasms of the parents can then produce 

 nothing whatever which is new, and yet new forms have (as 

 the Professor would be the first to assert) constantly and 

 repeatedly arisen. He will no doubt explain these novelties 

 as results of conflicting tendencies, producing in each case a 

 tertium quid. But this is a mere verbal explanation which 

 is equivalent to the abandonment of his whole theory. If 

 the germ-plasms of each or either parent is thus modifiable, 

 it is not, as he affirms, rigidly confined to a mere exact 

 repetition of what it has been. It must possess some peculiar 

 plastic power and a capacity for reciprocal influence which, 

 when deeply considered, will be seen to be fully as mysterious 

 as any of the phenomena the Professor set out to explain. 



But the extreme complexity of his theory seems to us to 

 be also fatal to it. He admits that the complexity of Pan- 

 genesis is too great for belief, but that of his own hypothesis 

 is at least as great. He tells us (p. 191) that ' every detail of 

 the whole organism must be represented in the germ-plasm 

 by its own special and peculiar arrangement of molecules,' 

 and (p. 146) that ' the number of generations of somatic cells 

 which can succeed one another in the course of a single life 

 is predetermined in the germ.' 



Moreover, none of these circumstances can be explained 

 by any difference of quality (since at p. 101 he has denied 

 the existence of such a thing as quality), and must therefore 

 be supposed to be due to differences in the size, number, and 

 arrangement of the component parts, and to nothing else. 



If we only consider what must be the complexity of the 

 arrangement of minute structures in order that that arrange- 

 ment alone may efficiently determine once for all in the 

 germ, the precise number of all the epithelial scales of the 

 skin which have to be cast off during the whole of sub- 



