CHAPTER XII. 



AGE BT TBGE TEETH. 



By their growth, changes, form, and wear, the teeth of the horse 

 furnish a very rehable guide to determine the animal's age. In the 

 adult animal they number from 36 in the female to 40 in the male, 

 and are classed according to their location, form, and function, as 

 incisors, canines, and molars. 



The incisors, or cutters, occupy the front part of the mouth. They 

 are 12 in number, 6 in the upper jaw and 6 in the lower. In each 

 jaw there are 2 central, 2 lateral, and 2 comer incisors. 



The canines, or tushes, occupy the front part of the interdental 

 space. The tushes are usually absent in the mare, or, if present, 

 are very small. They are 4 in number, 2 in each jaw. 



The molars, or grinders, occupy the back part of the mouth. They 

 are 24 in number, 6 on each side of each jaw. Naming from front to 

 rear they are designated first, second, third, etc. Quite frequently 

 supplementary molars, called "wolf teeth," are present. If so, they 

 appear directly in front of the first molar, in the upper jaw, and very 

 rarely in the lower jaw. 



Like other animals, the horse is provided with two sets of teeth, 

 temporary and permanent. The temporary, or milk teeth, are those 

 of the first growth or dentition. They are 24 in number, 12 incisors 

 and the first, second, and third molars. They are all up and in wear 

 when the colt is about 11 months old. Each of them is ultimately 

 shed and replaced by a permanent tooth. The first shedding takes 

 place at 2^ and the last is completed at 4^ years of age. The first 

 permanent tooth to show itself, however, is the fourth molar, which 

 appears at about the age of 1 year. 



The permanent incisor differs in appearance from the temporary 

 one by being larger, longer, darker, or more yellowish in color, and 

 by having a well-marked groove down the anterior or front face of 

 the crown. It does not have the constricted neck which is charac- 

 teristic of the milk tooth. 



The thtee principal tooth substances are called dentine, enamel, 



and cement. The dentine" composes the main body of the tooth. It 



is protected by a covering of enamel, which is very white in color and 



is the hardest of all animal substances. The cement is a yellowish 



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