II OF THE NATURAL HISTORY SCIENCES 51 



Eosaceas, for instance, or tlie class of Fishes, is not 

 accurately and absolutely definable, inasmuch as 

 its members will present exceptions to every pos- 

 sible definition and that the members of the 

 class are united together only by the circumstance 

 that they are all more like some imaginary aver- 

 age rose or average fish, than they resemble any- 

 thing else. 



But here, as before, I think the distinction has 

 arisen entirely from confusing a transitory imper- 

 fection with an essential character. So long as 

 our information concerning them is imperfect, we 

 class all objects together according to resemblances 

 which we feel, but cannot define; we group them 

 round types, in short. Thus if you ask an ordi- 

 nary person what kinds of animals there are, he 

 will probably say, beasts, birds, reptiles, fishes, in- 

 sects, &c. Ask him to define a beast from a rep- 

 tile, and he cannot do it; but he sa3^s, things like 

 a cow or a horse are beasts, and things like a frog 

 or a lizard are reptiles. You see he does class by 

 type, and not by definition. But how does this 

 classification differ from that of a scientific Zoolo- 

 gist? How does the meaning of the scientific class- 

 name of " Mammalia " differ from the unscientific 

 of "Beasts"? 



a genus, which is considered as eminently possessing the 

 characters of the class. All the species which have a greater 

 affinity with this type-species than with any others, form 

 the genus, and are ranged about it, deviating from it in va- 

 « rious directions and different degrees." — Whewell, The 

 Philosopluj of the Indudice Sciences, vol. i. pp. 476, 477. 



