CHAPTER XXII. 



CLASSIFICATION. 



Classifica- rpHE subject of classification is mucli more familiar than 

 depends ^^^^ °^ embryology, and, apparently, has to do with 



on Embry- much more obvious facts. Nevertheless, classification as 

 ° °^^' now understood depends on embryology ; for which reason 



I have treated of embryology first. 

 "What is At the end of the last chapter I used an expression 

 ^g'^^g^/gf which to many may appear strange. I spoke of the 

 classifica- fads of classification. It may be asked : " What does 

 this expression mean ? What is classification but an 

 affair of words and names? What other merit can the 

 best classification have, than that of being the most 

 convenient 1 " 

 Questions I have in a former chapter^ stated my conviction, which 

 catira are ^^ ^^^^ °^ most if not all men who have given any attention 

 real. and thought to the classificatory sciences, that there is not 



only a distinction in classification of convenient or incon- 

 venient, but also a distinction of true or false. It is 

 perhaps difficult to prove this to the satisfaction of any 

 one who has not a general familiarity with the outlines of 

 those sciences ; for such a conclusion is not like a mathe- 

 matically demonstrated proposition, which is necessarily 

 assented to as soon as the reasoning is understood on 

 which it rests ; on the contrary, the general conclusions of 

 biological science mostly depend on cumulative evidence 

 derived from a variety of facts of various kinds, and of 

 very different degrees of importance. 



1 See p. 117. 



