136 MR. BLYTH ON THE BRITISH WARBLERS. 



particular habit or peculiarity common to the whole group ; or 

 which would at any rate more especially apply to that particular 

 group, than to any other. 



To a person conversant with natural history a generic name, to be 

 appropriate, ought to convey at once to the mind a distinct and 

 definite notion of the kind of animal to which it is affixed. Thus, 

 speaking of a bird, if we call it according to the old system of 

 nomenclature, a finch, ( Fringilla,) we convey at best but a very 

 vague and indefinite idea of it : it may be a siskin, or a sparrow, or 

 it may be of the chaffinch kind, or of some other of those distinct 

 and very natural groups into which the small granivorous birds, 

 called finches, are now usually divided ; groups distinguished even 

 in common language, but confused together by the old writers under 

 that one name, Fringilla. But if, however, according to more mo- 

 dern arrangement, we style the bird a Carduelis, (siskin and goldfinch 

 genus,) a Linaria (linnet,) or a Coccothraustes, (grosbeak or hawfinch 

 genus,) and call it also one of the Fringillina, not only do we convey 

 the idea that it is a finch, but we express also that particular family 

 of finches to which it belongs. 



By this method of arrangement, we certainly avoid the incongruity 

 of classing animals of different natures and habits in one genus j 

 while, by uniting under one general appellation the various modifica- 

 tions of the different leading forms, thus comprising, for example, 

 the several genera of finches under the term Fringillina, or the vari- 

 ous warblers under Sylviana, we possess, also, in addition, every pos- 

 sible advantage that could be derived from the former system of 

 classification. 



But while we thus confine a generic, appellation within smaller 

 and more natural limits, we must at the same time be cautious not 

 to run into the opposite extreme ; and we must also be continually 

 on our guard against that strange but decided tendency in the 

 human mind, to imagine a greater uniformity in nature than actually 

 exists : an illusion which in all ages has manifested itself more or 

 less in every branch of science, and which has given rise to more 

 theoretical absurdity than the aggregate of all the other sources of 

 error, so acutely descanted upon by Lord Bacon. There is, there- 

 fore, no necessity for stiffening our arrangements into exact quinary, 

 or trinary sections, with which it is now so much the fashion to 

 cramp our ideas of nature : all such frivolities having an obvious 

 and manifest tendency to contract our ideas, to shut from our per- 

 ception whatever militates against a favourite theory, to superinduce 



