THE HORSE AS A MILLER. 



73 



In spite of all these changes, it is a rare thing to see 

 a missing incisor or grinder ; but the canines,, owing 

 perhaps to their sharp points, not only wear out, but 

 now and then, in extreme old age, fall out. 



The permanent teeth agree with 

 the temporary in but few respects, 

 though the general appearance of 

 the respective teeth is nearly the 

 same. They differ in many respects. 

 Their bodies are larger and denser, 

 and their roots longer and stronger. 

 The grooving of the incisors is the 

 reverse ; the outer surface is usually 

 double grooved, the inner smooth, 

 both being slightly rounded. They 

 are less upright in position, and less 

 sharp, but are more discolored, and 

 the marks are wider and deeper and 

 wear out more slowly. They attain 

 their growth more slowly, and a 

 healthy tooth continues to grow 

 throughout life. This latter quality 

 is a wise provision of Nature, as but 

 for it a horse's teeth, particularly its 

 grinders, would be worn to stubs in 

 two or three years after full growth. 

 The annexed cut shows how a mo- 

 lar, owing to the loss of the opposite 

 tooth, grew till it killed the horse. 



Growth, say Bouley and Ferguson, 

 compensates for the enormous wear 

 of the teeth, the horse having to 

 perform for himself that which the 

 miller performs for man, thus pre- 

 serving for a long time, if not their 

 form, at least their length. 



Chauveau, referring to the horse, says : " The 

 permanent teeth present in their development a 

 common but very remarkable characteristic, rarely 



Back lower molar ; extra 

 growth begins at dotted line. 



