138 PHILOSOPHY OF ZOOLOGY. 



In order to exhibit the mutual relations of animals, by 

 distributing them into groups, the naturalist may employ 

 two different methods, which will not, however, furnish the 

 same results, or lead to the same combinations. 



If we attend to any system of organs, we speedily dis- 

 cover that it exhibits in the different species a variety of mo- 

 difications. In some, it exists in its simplest, in others, in 

 its most complex form ; and between these extremes, there 

 are many conditions distinguished by the presence or ab- 

 sence of particular parts, or by equally obvious variations 

 of form or structure. In reference to the cutaneous system, 

 we have already seen that it possesses hair in some, feathers 

 in others, or scales, shells, or crusts, while in many, it is 

 destitute of these appendices. We have here both positive 



any thing ; hence the law by which all hoofed animals are herbivorous, 

 and also those still more detailed laws which are but corollaries of the first, 

 that hoofs indicate dentes molares with flat crowns, a very long alimentary 

 canal, a capacious or multiplied stomach, and several other relations of the 

 same kind." P. 55. This specious reasoning, would certainly lead to the 

 admission of these necessary laws of co-existence, were the statements advan- 

 ced correct in all their bearings. But the operations of Nature are not re- 

 strained by such trammels. Quadrupeds possessing the common quality of 

 being carnivorous, have not all the same number of teeth, nor of the same 

 shape, neither the same kind of stomach or intestines. Again, all herbivo- 

 rous animals are not hoofed, for many of them are digitated as the hare. All 

 hoofed animals have not flat crowned teeth, like the bull, nor pointed teeth 

 like the boar, nor a simple stomach like the horse, nor deciduous horns like 

 the stag, nor a reservoir for drink like the camel, nor digestive organs that 

 do not require any like the sheep. Indeed, the number of varieties included 

 under one species, the number of species belonging to a genus, and the num- 

 ber of genera in an order, intimate the variableness of the conditions of co- 

 existence, and the absence of those supposed laws of relation, the belief in the 

 mathematical necessity of which, has contributed to augment the clumsy fabric 

 of modern Materialism." 



