b ERYTHEA. 



In order to get clear ideas on the matter let tis look at the 

 logical principles on which such names are based. It is for- 

 tunate for us that these are stated by Mill, who, besides 

 being an authority on logic, was also an accomplished 

 botanist. He tells us:^'' 'A naturalist, for purposes con- 

 nected with his particular science, sees reason to distribute 

 the animal or vegetable creation into certain groups rather 

 than into any others, and he requires a name to bind, as it 

 were, each of his groups together.' He further explains 

 that such names, whether of species, genera or orders, are 

 what logicians call connotative: they denote the members of 

 each group, and connote the distinctive characters by which 

 it is defined. A species, then, connotes the common charac- 

 ters of the individuals belonging to it; a genus, those of the 

 species; an order, those of the genera. 



But these are the logical principles which are applicable 

 to names generally. A name such as Ranunculus repens 

 does not differ in any particular from a name such as John 

 Smith, except that one denotes a species, the other an 

 individual. 



This being the case, and technical names being a necessity, 

 they continually pass into general use in connection with 

 horticulture, commerce, medicine and the arts. It seems 

 obvious, that if science is to keep in touch with human 

 affairs, stability in nomenclature is a thing not merely to aim 

 at but to respect. Changes become necessary, but should 

 never be insisted on without grave and solid reason. In 

 some cases they are inevitable unless the taxonomic side of 

 botany is to remain at a standstill. From time to time the 

 revision of a large group has to be undertaken from a 

 uniform and comparative point of vieAv. It then often occurs 

 that new genera are seen to have been too hastily founded 

 on insufficient grounds, and must therefore be merged in 

 others. This may involve the creation of a large number of 

 new names, the old ones becoming henceforth a burden to 

 literature as synonyms. It is usual in such cases to retain 



^TSystem of Logic, i. 132. 



