258 ESSAY ON CLASSIFICATION. 



are all organized upon a distinct plan, differing from the 

 plan of other types. 



Individuals, then, are the bearers, for the time being, 

 not only of specific characteristics, but of all the natural 

 features in which animal life is displayed in all its diversity. 



Viewing individuals in this light, they resume all their 

 dignity; and they are no longer so absorbed in species 

 as to be ever its representatives without being any- 

 thing for themselves. On the contrary, it becomes plain, 

 from this point of view, that the individual is the worthy 

 bearer, for the time being, of all the riches of nature's 

 wealth of life. This view further teaches us how we may 

 investigate not only the species in the individual, but also 

 the genus, the family, the order, the class, the branch, as 

 indeed naturalists have at all times done in practice, 

 whilst denying the possibility of it in theory. 



Having thus cleared the field of what does not belong 

 to it, it now remains for me to show what in reality 

 constitutes species, and how they may be distinguished 

 with precision within their natural limits. 



If we would not exclude from the characteristics of 

 species any feature which is essential to it, nor force into 

 it any one which is not so, we must first acknowledge 

 that it is one of the characters of species to belong to a 

 given period in the history of our globe, and to hold defi- 

 nite relations to the physical conditions then prevailing, 

 and to animals and plants then existing. These relations 

 are manifold, and are exhibited: 1st, in the geographical 

 range natural to any species, as well as in its capability 

 of being acclimatized in countries where it is not primi- 

 tively found; 2nd, in the connection in which they stand 

 to the elements around them, when they inhabit either 

 the water or the land, deep seas, brooks, rivers and lakes, 



