TERMINOLOGY AND NOMENCLATURE. 493 



§ 5. A word which carries on its face that it belongs to a nomenclature, 

 seems at first sight to differ from other concrete general names in this — 

 that its meaning does not reside in its connotation, in the attributes im- 

 plied in it, but in its denotation, that is, in the particular group of things 

 which it is appointed to designate; and can not, therefore, be unfolded by 

 means of a definition, but must be made known in another way. This 

 opinion, however, appears to me erroneous. Words belonging to a no- 

 menclature differ, I conceive, from other words mainly in this, that besides 

 the ordinary connotation, they have a peculiar one of their own : besides 

 connoting certain attributes, they also connote that those attributes are 

 distinctive of a Kind. The term " peroxide of iron," for example, belong- 

 ing by its form to the systematic nomenclature of chenjistry, bears on its 

 face that it is the name of a peculiar Kind of substance. It moreover con- 

 notes, like the name of any other class, some portion of the properties 

 common to the class ; in this instance the property of being a compound 

 of iron and the largest dose of oxygen with which iron Avill combine. 

 These two things, the fact of being such a compound, and the fact of being 

 a Kind, constitute the connotation of the name peroxide of iron. When 

 we say of the substance before us, that it is the peroxide of iron, we there- 

 by assert, first, that it is a compound of iron and a maximum of oxygen, 

 and next, that the substance so composed is a peculiar Kind of substance. 



Now, this second part of the connotation of any word belonging to a 

 nomenclature is as essential a portion of its meaning" as the first part, while 

 the definition only declares the first ; and hence the appearance that the 

 signification of such terms can not be conveyed by a definition : which ap- 

 pearance, however^ is fallacious. The name Viola odorata denotes a Kind, 

 of which a certain number of characters, sufficient to distinguish it, are 

 enunciated in botanical works. This enumeration of characters is surely, 

 as in other cases, a definition of the name. No, say some, it is not a defi- 

 nition, for the name Viola odorata does not mean those characters; it means 

 that particular group of plants, and the characters are selected from among 

 a much greater number, merely as marks by which to recognize the group. 

 But to this I reply, that the name does not mean that group, for it would 

 be applied to that group no longer than while the group is believed to be 

 an injima species ; if it were to be discovered that several distinct Kinds 

 have been confounded under this one name, no one would any longer ap- 

 ply the name Viola odorata to the Avhole of the group, but would apply it, 

 if retained at all, to one only of the Kinds retained therein. What is im- 

 perative, therefore, is not that the name sliall denote one particular collec- 

 tion of objects, but that it shall denote a Kind, and a lowest Kind. The 

 form of the name declares that, happen what will, it is to denote an injima 

 species y' and that, therefore, the properties which it connotes, and which 

 are expressed in the definition, are to be connoted by it no longer than 

 while we continue to believe that those properties, when found together, 

 indicate a Kind, and that the whole of them are found in no more than one 

 Kind. 



With the addition of this peculiar connotation, implied in the form of 

 every word which belongs to a systematic nomenclature ; the set of char- 

 acters which is employed to discriminate each Kind from all other Kinds 

 (and which is a real definition) constitutes as completely as in any oth- 

 er case the whole meaning of the term. It is no objection to say that 

 (as is often the case in natural history) the set of characters may be 

 changed, and another substituted as being better suited for the purpose 



