GERMINAL SELECTION. 59 



dered conceivable how these diverse and extremely 

 minute adaptations could have developed side by side 

 in the same germ-plasm, under the guidance of selec- 

 tion; how sterile forms could be hereditarily estab- 

 lished and transformed in just that manner which 

 best suits with their special duties; and how they 

 themselves under the right circumstances could sub- 

 sequently split up into two or even into three new 

 forms. Surely at least the unclear conception of an 

 adaptively transformative influence of food must be 

 discarded. It is true, we cannot penetrate by this 

 hypothesis to the last root of the phenomena. The 

 hotspurs of biology, who clamor to know forthwith 

 how the molecules behave, will scarcely repress their 

 dissatisfaction 1 with such provisional knowledge for- 

 getful that all our knowledge is and remains through- 

 out provisional. 



But I shall not enter more minutely into the ques- 

 tion whether epigenesis or evolution is the right foun- 

 dation of the theory of development, but shall content 

 myself with having shown, first, that it is illusory to 

 imagine that epigenesis admits of a simpler structure 

 of the germ, (the precise opposite is true,) and sec- 

 ondly, that there are phenomena that can be understood 

 only by an evolution-theory. Such a phenomenon is 



1 Nor will those, who demand a demonstration of "how the 

 biophores and determinants are constituted in every case, 

 and must be arranged in the architecture of the germ-plasm." 

 (O. Hertwig, loc. cit., p. 137). As if any living being could 

 have the temerity even so much as to guess at the 

 actual ultimate phenomena in evolution and heredity! The 

 whole question is a matter of symbols only, just as it is in the 

 matter of "forces," "atoms," "ether undulations," etc., the 

 only difference being that in biology we stumble much earlier 

 upon the unknown than in physics. 



