in the " Dictionnaire des Sciences NaturellesJ''' 97 



before us should be called sections, while equivalent subdivisions 

 in equivalent groups are called genera, I can see no reason ; and 

 against the arbitrary mandate that issues such a law I must 

 decidedly enter my protest. I proceed to support this protest by 

 insisting upon the two following points : first, that these subdivi- 

 sions of the Psitlacidce, whatever may be the name by which we 

 think fit to call them, are bona fide genera, according both to the 

 philosophical signification of the terra genus, and the particular 

 adaptation of it to Natural History ; and secondly, that the same 

 groups are marked by equally distinctive characters, and are kept 

 apart by equal differences in the modes of life of the birds which 

 compose them, as are found in any other of the admitted genera 

 in Ornithology. 



What, in short, is a genus ? Are we to conclude from the ob- 

 servations of M. Desmarest, that there is something sacred in the 

 word, when once it has been attached to a group, that prevents 

 any future interference with it : — that it represents, in short, the 

 real essence of the subjects for which it stands, and will conse- 

 quently admit of neither change nor modification ? Or rather, 

 in accordance with the opinion of one of our first philosophers, 

 should we not consider a genus to " belong not to the real existence 

 of things," but to be " the creature and invention of the under- 

 standing ;" and to represent an assemblage which has been brought 

 together in our ideas by the usual process of generalization, and 

 invested with a name, for the more convenient communication of 

 knowledge ? 



Such at least is the usual acceptation of the term. — " A general 

 idea^" says Dr. Watts, " is called a genus ^ and it is one common 

 nature agreeing to several other common natures."* — "All the 

 great business of genera and species," observes Mr. Locke, 

 " amounts to no more but this, That men making abstract ideas, 

 and settling them in their juinds with names annexed to them, do 

 thereby enable themselves to consider things, and discourse of 

 them as it were in bundles, for the easier and readier improvement 

 and communication of their knowledge ; which would advance 

 but slowly were their words and thoughts confined only to partfcu- 

 * Logic. Part I. chapt. III. sect. III. p. 34. 



Vol. III. , a 



