144 



ALIMENTARY ORGANS. 



that wonderful design we discover in the animal 

 system. If the nature of the stomach be such as is 

 the case in cats, tigers, lions, &c. that it will only 

 digest animal food the teeth are particularly fitted 

 for tearing and separating flesh. On the contrary, if 

 the nature of the digestive organs be such as to re- 

 quire vegetable food, as in the horse, ox, and many 

 others, the teeth are flat, rough and of large surface 

 resembling a millstone, and fitted only for grinding. 

 The grinder of a horse or an ox, is a mechanical curi- 

 osity. There are ridges of the hardest enamel which 

 rise up above the surface and run down to a consid- 

 erable depth. These ridges are filled in between with 

 a somewhat softer substance resembling marble ; the 

 consequence of which is, that the spaces wear away 

 easier than the ridges, and thus the tooth is kept 

 always rough and fit for the operation of breaking and 

 grinding the vegetable substances upon which the an- 

 imal lives. 



Fig. 28. 



A Grinder, or one of the Molares of a horse, (from a Latin word 

 signifying a mill stone) ; a. the enamel forming a raised 

 edge around the tooth : the white lines in the middle repre- 

 senting the plates of enamel in the interior of the tooth, 

 b. the earthy part interposed, which, by wearing away more 

 easily, leaves the ridges of enamel projecting above. 



