UNIVERSAL CHARACTERS OBJECTIONABLE. 239 



characters from the same organs, or from the same 

 premises. And, indeed, if we consider the subject 

 for a moment, it is impossible they should ; because 

 such divisions rest only upon individual opinion, 

 without reference to any common standard by 

 which such opinions can be judged. It is clear, 

 also, that the same organs will have different degrees 

 of consequence in different classes. By taking the 

 form, number, and disposition of the teeth into 

 consideration, we bring the quadrupeds into large 

 but very natural divisions ; but to carry on the same 

 set of characters to fish, and make their dentation 

 the chief guide in their arrangement, would be 

 manifestly absurd, if not impossible. Hence it 

 follows, that not only in a natural, but also in an 

 artificial system, there are no organs in animals 

 which can be universally employed to furnish 

 generic characters, and to which we must exclu- 

 sively direct our attention. The question, then, 

 arises, by what rules are we to be guided in defining 

 such divisions, and in giving them a stability which 

 artificial groups have not ? 



(165.) When, therefore, the naturalist, following 

 the principles already detailed, has before him a 

 generic group, whose affinities, more or less, appear 

 to be circular, he is next to seek for those charac- 

 ters which are most prevalent in all the forms or 

 species which compose it. It is a matter of perfect 

 indifference, what organ, or what set of organs, fur- 

 nish these characters, provided they are more com- 

 prehensive than others, and are of such a nature as 

 to be readily detected. His great object, in fact, 

 is to point out, with clearness and precision, how 



