THEORY OF THE KAKTH. 89 



If we proceed to consider the orders or subdi- 

 visions of the class of hoofed animals, and examine 

 what modifications the general conditions under- 

 go, or rather what particular conditions are con- 

 joined with them, according to the respective cha- 

 racters of these orders, the reasons of these subor- 

 dinate conditions begin to appear less obvious. 

 We can still easily conceive, in general, the ne- 

 cessity of a more complicated system of digestive 

 organs in those species which have a more im- ^ 

 perfect masticatory system ; and hence we may 

 presume, that these latter must be rather rumi- 

 nating animals, in which there is wanting such 

 or such an order of teeth ; and may also deduce 

 from the same consideration, the necessity of a 

 certain form of the oesophagus, and of correspond- 

 ing forms in the vertebrae of the neck, &c. But 

 I doubt whether it would have been discovered, 

 independently of actual observation, that the ru- 

 minating animals should all have cloven hoofs, 

 and that they should be the only animals having 

 them ; that there should be horns on the fore- 

 head in this class alone ; or that such of them as 

 have sharp canine teeth, should, in general, have 

 no horns. 



However, since these relations are constant, we 

 may be assured that they have a sufficient cause ; 

 but as we are not acquainted with that cause, we 

 must supply the defect of theory by means of ob- 

 servation, and in this way establish empirical laws 



