THE TEETH IN" GENERAL 29 



food with the saliva. This function is also per- 

 formed by the tongue and cheeks. 



Of the secondary functions of the teeth, war- 

 fare is the most important. The canines of the 

 carnivora are developed for prehensile purposes 

 but they are also used in combat and to destroy 

 animal life. The nature of an animal can be told 

 by the teeth. Associated with warfare for pro- 

 tection and securing of the food is sexual war- 

 fare. We find the teeth of some animals are bet- 

 ter developed in the males than in the females. 

 In some animals we have the function of sexual 

 attraction closely associated with sexual warfare. 

 The canines are well developed in some males, 

 e.g., the boar, but the growth of those teeth is 

 checked by castration and the teeth of the cas- 

 trated males become no larger than the teeth of 

 the females. Teeth are also used as tools, an 

 example of which is the beaver, which uses the 

 teeth to gnaw off trees which are used in the 

 making of their dams and houses. The lower 

 anterior teeth of the lemur are used to dress their 

 fur and have a modified cosmetic function. In 

 man we find the teeth have a function in speech; 

 they also have an esthetic function and through 

 the esthetic function also have a function of sex- 

 ual attraction. 



The food-reducing mechanism of animals pre- 

 sents great variety when viewed throughout the 



