CLASSIFICATION. 437 



surprise the reader. They are so contrary to many of the received 

 opinions respecting the use of" definitions, and the nature of scicntitic 

 propositions, that they will probably appear to many persons highly 

 illogical and unphilosophical. But a disposition to such a judgment 

 arises in a great measure from this, tliat the mathematical and 

 mathematico-physical sciences have, in a great degree, determined 

 men's views of the general nature and fonii of scientific truth ; while 

 Natural Histoiy has not yet had time or opportunity to exert its due 

 influence upon the current habits of philosophizing. The ajiparent 

 indefiniteness and inconsistency of the classifications and definitions of 

 Natural History belongs, in a far higher degree, to all other except 

 mathematical speculations ; and the modes in which approximations 

 to exact distinctions and general truths have been made in Natural 

 History, may be worthy our attention, even for the light they throw 

 upon the best modes of pursuing ti-uth of all kinds." 



" Though in a Natural group of objects a definition can no longer 

 be of any use as a regulative principle, classes are not therefore left 

 quite loose, without any certain standard or guide. The class is 

 steadily fixed, though not precisely limited ; it is given, though not 

 circumscribed; it is determined, not by a boundary line without, but 

 by a central pointwit hin; not by what it strictly excludes, but by what it 

 eminently includes ; by an example, not by a precept ; in short, instead 

 of Definition we have a Type for our director. 



" A Type is an example of any class, for instahee a species of a' 

 genus, which is considered as eminently possessing the character of 

 the class. All the species which have a greater afHnity with this tyye- 

 species than with any others, form the genus, and are ranged about 

 it, deviating froni it in various directions and different degrees. Thus 

 a genus may consist of several species which approach very near tlie 

 type, and of which the claim to a place with it is obvious; while there 

 may be other species which straggle further from this central knot, and 

 which yet are clearly more connected with it than with any other. 

 And even if there should be some species of which the place is dubi- 

 ous, and which appear to be equally bound to two generic types, it is 

 easily seen that this would not destroy the reality of the generic 

 groups, any more than the scattered trees of the intervening plain 

 prevent our speaking intelligibly of the distinct forests of two sep- 

 arate hills. 



" The type-species of every genus, the type-genus of every family, 

 is, then, one which possesses all the characters and properties of the 

 genus in a marked and prominent manner. The type of the Rose 

 family has alternate stipulate leaves, wants tlie albumen, has the ovules 

 not erect, has the stigmata simple, and besides these features, which 

 distinguish it from the exceptions or varieties of its class, it has the 

 features which make it prominent in its class. It is one of those which 

 possess clearly several leading attributes ; and thus, though wo cannot 

 say of any one genus that it 7nu.'st be the type of the family, or of any 

 one species that it must be tlie type of the genus, we are still not 

 wholly to seek ; the type must be connected by many affinities with 

 most of the others of its group ; it must be near the centi'e of the 

 crowd and not one of the stragglers." 



In this passage (the latter part of which especially I cannot help no- 

 ticing as an admirable example of philosophic style,) Mr, WlieweU 



