ITS MEANING AND DIVISIONS. 193 



universal genetic principle, which is the fore- 

 going total Earth-life. 



It may be added that the present field, the 

 Particularized Biocosmos, furnishes the su- 

 preme opportunity for the comparison of 

 these Life-forms and their manifold evolu- 

 tionary phenomena. There is a Plant-norm 

 with a double line of shapes reaching from 

 the lowest to the highest and from the remote 

 geologic past to the present ; all these vegetal 

 shapes are to be compared and ordered in- 

 ternally and externally in what may be called 

 a comparative Botany. In like manner, there 

 is an Animal-norm, with its double line of 

 shapes reaching from the lowest to the high- 

 est and from the far-off past to the present ; 

 here is the domain of a comparative Zoology. 

 And the science of Earth-life, Geology, is also 

 largely comparative, embracing the Inorganic 

 as well as the Organic. Thus we discern in 

 the present subject as a whole the Compara- 

 tive Biocosmos which seeks to order and 

 hence to unify all this diversity of particular- 

 ized Life according to its essential relation- 

 ships. 



Science has by no means attained any such 

 general principle of biological' comparison, 

 though searching for it ardently, as we see 

 by the many shiftings of the standard of clas- 

 sification for both plants and animals in re- 



