GERMINAL SELECTION. 57 



or species, must be contained in the germ, the obli- 

 gation rests on these similar units, or rather the ca- 

 pacity is required of them, to produce in themselves 

 a truly enormous number of differences. But this is 

 possible only provided their composition is an exceed- 

 ingly complex one, or only on the condition that in 

 every one of them are contained as many alterable par- 

 ticles as according to my view there are contained 

 determinants in the whole germ. The diiferences that 

 I put into the whole germ, Spencer and his followers 

 are obliged to put into every single unit of the germ- 

 inal substance. My position on this point appears to 

 me incontrovertible so long as it is certain that the 

 single characters can vary hereditarily ; for, if a thing 

 can vary independently, that is, of its own accord, and 

 from the germ, then that thing must be represented in 

 the germ by some particle of the substance, and be 

 represented there in such wise that a change of the 

 representative particle produces no other change in 

 the organism developing from the germ than such as 

 are connected with the part which depends on it. I 

 conceive that even on the assumption of my constitu- 

 tional elements (Anlagen) the germ-plasm is complex 

 enough, and that there is no need of increasing its 

 complexity to a fabulous extent. Be that as it may, 

 the person who fancies he can produce a complex 

 organism from a really simple germinal substance is 

 mistaken: he has not yet thoroughly pondered the 

 problem. The so-called "epigenetic" theory with its 

 similar germinal units is therefore naught else than 

 an evolution-theory where the primary constitutional 

 elements are reduced to the molecules and atoms— 

 a view which in my judgment is inadmissible. A real 



