258 NATURAL THEOLOGY. 



To commence with the manner in which the 

 teeth resist pressure into the jaw. If we look to 

 the teeth of the Hon, we find their roots conical 

 and socketed, as if a nail were driven in ; and so 

 it is in the remarkably strong teeth of the hyaena. 



The figure represents the back tooth of the Tiger's jaw, which 

 closes Hke the blade of scissors. 



Now these animals have powerful muscles, 

 closing the jaws with a force to break the strongest 

 bone. How is it then that the teeth are never 

 pressed deeper into the jaw? For undoubtedly 

 this would be the effect in an engine so constructed 

 by man's ingenuity. The reason is, that there is 

 a living property in the teeth and jaw, by which 

 the former are made to protrude from their sock- 

 ets, in proportion to the pressure to which their 

 crowns, that is, their exposed parts, are subject- 

 ed. It is very remarkable that the teeth, during 

 their period of growth, notwithstanding they are 

 exposed to the pressure of mastication, will 

 ascend or protrude more and more out of the 



