90 



DISEASES OF THE TEETH. 



occurred, signs of difficult mastication are perceptible, and 

 soon a swelling of the face and imperfect passage of air 

 through the nose are observed. 



Pig. 46. 



CAEIES is unquestionably the malady most frequently 

 affecting the teeth of man and animals. It consists in struc- 

 tural degeneration of the enamel and dentine, though even 

 the cement around the fang may become the seat of disease. 

 Mayhew gives a drawing of a molar tooth in which the crusta 

 petrosa appears to have been partly thickened and partly 

 ulcerated. In considering the diseases of the teeth in the 

 lower animals, we must not forget that the molars are cer- 



