NATURAL HISTORY. 35 



; But of this frame the bearing and the ties, 

 The strong connexions, nice dependencies, 

 Gradations just, has thy pervading soul looked through?" POPE. 



94. Why are the gums admirably fitted to receive tJie teeth f 



Because they not only serve as firm elastic cushions whereby 

 they rapidly diffuse the force, and powerfully support the teeth 

 when forcibly employed, but by the vascular connection between 

 them, in part supply them with nourishment 



95. By the manner in which teeth are implanted in the sockets, they are afforded 

 an extensive surface of support. The force is not concentrated at the point, as lu 

 the case of a nail thrust into a board ; but is uniformly diffused over the whole 



L surface of the fang, as may be seen in the 



annexed engraving, where the fangs of 

 the middle toota P ress on a surfa ce, a a , 

 equal to four times that of the crown, 

 6 ; so that supposing the pressure on the 

 crown to be equai to four pounds, being 

 extended over the surface of the fangs, 

 it is reduced to one pound on any given 

 point of the root, and with a similar force 

 upon the sockets. 



96. Why are ike teeth of infants hidden within the gums! 



Because the presence of teeth would not only be useless, but 

 would interrupt the process of sucking, by which means the infant 

 is for some time nourished, and which act can be performed more 

 efficiently, and with greater ease and comfort to the nurse, whilst 

 the inside of the mouth and edges of the gums are smooth and soft. 



97. What renders it more probable that this is the effect of design is, that tho 

 teeth are imperfect while all the other parts of the mouth are perfect. The lips are 

 perfect ; the tongue is perfect; the cheeks, the jaws, the palate, the pharynx, tho 

 larynx, are all perfect; the teeth alone are not so. All these parts are called into 

 use from the beginning. 



98. Why do new teeth sometimes make their appearance at an 

 advanced age ? 



In such cases the jaw was too small to contain the full 

 number of the second set of teeth at the ordinary period of their 

 renewal ; some of the teeth, therefore, remain in the jaw, which 

 when others drop out make their appearance. 



