CLASSIFICATION BY SERIES. 289 



bution ; each of them corresponding to a definite portion of 

 the scale. In like manner each family should, if possible, be 

 so subdivided, that one portion of it shall stand higher and the 

 other lower, though of course contiguous, in the general scale ; 

 and only when this is impossible is it allowable to ground the 

 remaining subdivisions on characters having no determinable 

 connexion with the main phenomenon. 



Where the principal phenomenon so far transcends in 

 importance all other properties on which a classification could 

 be grounded, as it does in the case of animated existence, any 

 considerable deviation from the rule last laid down is in general 

 sufficiently guarded against by the first principle of a natural 

 arrangement, that of forming the groups according to the most 

 important characters. All attempts at a scientific classification 

 of animals, since first their anatomy and physiology were 

 successfully studied, have been framed with a certain degree of 

 instinctive reference to a natural series, and have accorded in 

 many more points than they have differed, with the classifi- 

 cation which would most naturally have been grounded on 

 such a series. But the accordance has not always been com- 

 plete ; and it still is often a matter of discussion, which of 

 several classifications best accords with the true scale of 

 intensity of the main phenomenon. Cuvier, for example, has 

 been justly criticized for having formed his natural groups 

 with an undue degree of reference to the mode of alimentation, 

 a circumstance directly connected only with organic life, and 

 not leading to the arrangement most appropriate for the 

 purposes of an investigation of the laws of animal life, since 

 both carnivorous and herbivorous or frugivorous animals are 

 found at almost every degree in the scale of animal perfection. 

 Blainville's classification has been considered by high authori- 

 ties to be free from this defect ; as representing correctly, by 

 the mere order of the principal groups, the successive 

 degeneracy of animal nature from its highest to its most 

 imperfect exemplification. 



5. A classification of any large portion of the field of 

 nature in conformity to the foregoing principles, has hitherto 

 VOL. n. 19 



