CLASSIFICATION. " 505 



ject in the class. There are always some properties common to all things 

 wlilch are included. Others there often are, to which some things, which 

 are nevertheless included, are exceptions. But the objects which are ex- 

 ceptions to one character are not exceptions to another; the resemblance 

 which fails in some particulars must be made up for in others. The class, 

 therefore, is constituted by the possession of ail the characters which are 

 universal, and most of those which admit of exceptions. If a plant had th6 

 ovules erect, the stigmata divided, possessed the albumen, and was without 

 stipules, it possibly would not be classed among the RosaceaB. But it may 

 want any one, or more than one of these characters, and not be excluded. 

 The ends of a scientific classification are better answered by including it. 

 Since it agrees so nearly, in its known properties, with the sum of the char- 

 acters of the class, it is likely to resemble that class more than any other in 

 those of its properties which are still undiscovered. 



Not only, thei'efore, are natural groups, no less than any artiiicial classes, 

 determined by characters ; they are constituted in contemplation of, and by 

 reason of, characters. But it is in contemplation not of those characters 

 only which are rigorously common to all the objects included in the group, 

 but of the entire body of characters, all of which are found in most of those 

 objects, and most of them in all. And hence our conception of the class, 

 the image in our minds which is representative of it, is that of a specimen 

 complete in all the characters ; most natnirally a specimen which, by pos- 

 sessing them all in the greatest degree in which they are ever found, is the 

 best fitted to exhibit clearly, and in a marked manner, what they are. It is 

 by a mental reference to this standard, not instead of, but in illustration of, 

 the definition of the class, that we usually and advantageously determine 

 whether any individual or species belongs to the class or not. And this, as 

 it seems to me, is the amount of truth contained in the doctrine of Types. 



We shall see presently that where the classification is made for the ex- 

 press purpose of a special inductive inquiry, it is not optional, but necessary 

 for fulfilling the conditions of a correct Inductive Method, that we should 

 establish a type-species or genus, namely, the one which exhibits in the most 

 eminent degree the particular phenomenon under investigation. But of this 

 hereafter. It remains, for completing the theory of natural groups, that a 

 few words should be said on the principles of the nomenclature adapted to 

 them. 



§ 5. A Nomenclature in science is, as we have said, a system of the 

 names of Kinds. These names, like other class-names, are defined by the 

 enumeration of the characters distinctive of the class. The only merit 

 which a set of names can have beyond this, is to convey, by the mode of 

 their construction, as much information as possible : so that a person who 

 knows the thing, may receive all the assistance which the name can give in 

 remembering what he knows; while he who knows it not, may receive as 

 much knowledge respecting it as the case admits of, by merely being told 

 its name. 



There are two modes of giving to the name of a Kind this sort of signifi- 

 cance. The best, but which unfortunately is seldom practicable, is when the 

 word can be made to indicate, by its formation, the very properties which 

 it is designed to connote. The name of a Kind does not, of course, connote 

 all the properties of the Kind, since these are inexhaustible, but such of 

 them as are sufficient to distinguish it ; such as are sure marks of all the 

 rest. Now, it is very rarely that one property, or even any two or three 



