go ELEMENTARY PHYSIOLOGY 



and we may now observe how this variety of action is still further 

 increased by the complex movement of the lower jaw. When we 



Fig. 88. Vertical Section of Premolar 

 of Cat. 



c, pulp-cavity ; i, enamel ; 2, dentine : 3, cement ; 

 4, periosteum ; 5, bone of the lower jaw. 



Fig. 89. Section of the Fang 

 of a Human Tooth. Magni- 

 fied 300 diameters. 



i, cement, with lacunae ; 2. tubes of 

 the dentine. 



bite our food we move the jaw perpendicularly, and make use 

 of the front or incisor teeth. After this, it is passed over, to the 



