CHAPTER IV. 



FUNCTION OF THE TEETH. 



The teeth have but a passive function to perform as ac- 

 cessory organs of prehension, mastication and insaliva- 

 tion, and as organs of defense. Their uses are similar in all 

 species, varying but slightly in detail. 



The incisors serve the general purpose of holding food, 

 after the lips or tongue have gathered it between them, and 

 as a jerk of the head detaches it. In the ingestion of de- 

 tached food they serve no useful purpose in any of the do- 

 mestic animals. In all the domestic mammals except rumi- 

 nants they are important organs of defense, and as such they 

 are most useful in the soliped. The incisors of carnivora are 

 so much shorter than the canines that the latter inflict the 

 greatest harm to an enemy. 



The canines of solipeds are common only to males, in 

 which animals they have no special function to perform. In 

 the carnivora and omnivora they serve the useful purpose 

 of tearing attached food preparatory to mastication, besides 

 constituting the principal organs of defense. In these ani- 

 mals they are common to both sexes and they lock over each 

 other in a manner to hold fast to any object into which they 

 are imbedded. 



The molars of herbivora are the mill-stones of the 

 mechanism of mastication. The wide, roughened tables of 

 the superior molars, and the series of strong muscles which 

 move the inferior ones upon them, constitutes the principal 

 features of a perfect grinding apparatus necessary to the 

 welfare of animals ingesting coarse, fibrous food. In these 

 animals the molars grind the food perfectly, carefully and 



127 



