DETERMINATION OF AGE BY THE TEETH. 207 



cutting edge or grinding surface, covered, as is the entire 

 crown, with enamel; B, the cementum covering the roots ; C, 

 the dentine; D, the pulp-cavity. Fig. 189 shows a transverse 

 section of a molar, of natural size, in which 1 is the dentine ; 2, 

 the enamel ; 3, the pulp-cavity. 



The pulp is not replaced by dentine as the animal becomes 

 adult, but remains vascular and with a nerve-supply, and when 

 exposed by disease of the tooth causes the toothache, which is 

 not possible in the adult herbivora. 



DETERMINxVTION OF AGE BY THE TEETH. 

 TEMPORARY DENTITION. 



The baby is born without teeth and depends entirely upon 

 the mother's milk or artificially prepared food which does not 

 require mastication until the fifth month, when the eruption, 

 called cutting teeth', so well known in every household, com- 

 mences with the central incisors. The lower teeth of each set 

 usually precede the upper by several weeks to two or three 

 months. 



The teeth usually appear in pairs, but often that of one side 

 precedes the other by some weeks, and in rare cases several 

 pairs may appear at once. The eruption of the teeth in the 

 baby is frequently attended with much pain, and sometimes by 

 srave and serious disturbance of the dioestive and nervous 

 systems, terminating even in death. These complications are 

 rare in other animals, but occasionally occur in young dogs, 

 which may have gastro-enteritis or convulsions during the erup- 

 tion of the permanent teeth, and we have already noted a case 

 of convulsions in a two-year-old colt. An intercurrent disease 

 during dentition may delay or alter its processes. 



An increased flow of saliva, hot and dry skin, constipation 

 and diarrhoea, eruptions of the skin and ulcers in the mouth 

 are frequent attendant symptoms of the appearance of the teeth. 

 Difficult dentition is accompanied by itching of the nose, twitch- 



