6 



Dentition as indicative of the Age 



crown of the tooth which projects above the gum ; the neck, 

 which is encircled by the gum ; and the fang, which is lodged 

 in its appropriate socket in the jaw. 



It will be observed that the temporary tooth is much smaller 

 than the permanent organ, which is placed on the left hand, 

 and also that the distinction between the upper part of the 

 tooth, or crown, and the fang is much more marked in the milk- 

 tooth. In fact, the permanent incisor does not indicate any 

 actual line of sej^aration between the upper and lower portions. 



For all practical purposes a knowledge of the form of the 



rig. 1. — Permanent and Temporary Incisors of Horse. 



B. Temporar}'. 



A Permanent. 



teeth, and especially the signs which distinguish the temporary 

 from the permanent organs, is quite sufficient. To the scientist, 

 the study of the minute structure and development of the teeth, 

 in their connection with the habits of the different classes of 

 animals, is very interesting, but it does not assist the practical 

 observer in judging the age. 



The next illustration (Fig. 2) shows a joerfectly formed 

 central permanent incisor. All the parts of the tooth which the 

 expert is required to note carefully are clearly defined in this 

 figure. 



