OTHER NATURAL SYSTEMS. 221 



thought to be effected by BarUcornes (an Erycinian 

 butterfly) and Lasiocampa. 



(271.) Without entering more into the details of 

 the various hypotheses last mentioned, it appears ex- 

 pedient, in this place, to recall the mind of the naturalist 

 to the essence of those remarks which have been given 

 more fully in another place*, and which are applicable 

 alike to all theories which set out with the admission of 

 the first law of natural classification the circularity of 

 groups. It is evidently easy, for it requires no great 

 ingenuity, to divide a group into three, four, five, seven, 

 or any other given number j but before such a division 

 can be called " natural," there are certain peremptory 

 conditions, which, in the present state of science, must 

 be complied with. The first of these is a demonstra- 

 tion of the theoretic principle upon which the author 

 builds his system. He is not merely to assert, but he is 

 to prove, that his fc natural" orders, or whatever other 

 denomination he affixes to his groups, are each of 

 them circles of affinity. To profess a belief in the cir- 

 cular system, and yet set at nought its practical exem- 

 plification, is childish; and, but for its inconstancy, 

 would injure science, by despising inductive reasoning. 

 An author who fixes upon any definite number, for the 

 division of an entomological group, should first prove 

 that the same number also exists in the ornithological 

 and all other zoological circles t, otherwise he tacitly 

 admits the monstrous and exploded supposition that 

 there is no uniformity of plan in the creation beyond 

 circles. If, therefore, the annulose kingdom, in its 

 primary divisions, is resolvable into seven circles, so 

 also must be the vertebrated kingdom : otherwise we 

 exhibit insects as created upon one plan, birds upon a 

 second, and quadrupeds (probably) upon a third. It 

 is really most disheartening to find naturalists (especially 



* Preliminary Discourse on Nat. Hist. p. 225. 



f The ingenious author of Sphinx Vespiformis, however, promises to do 

 this in a separate essay, already (1832) in a state of forwardness. .We 

 hope this will soon appear. If he is successful in establishing a more har- 

 monious theory than that which is already known, we shall be the first to 

 proclaim the fact. 



