142 THE PATHOLOGY OF THE TEETH. 



" There is in the museum of the College at Alfort a 

 horse's head in which this deformity may be seen in 

 its greatest degree. The tables of the teeth at the right 

 side form planes so much inclined that they close 

 together like the blades of sh.ears. As there was no 

 friction to wear the teeth down, they grew to the hight 

 of three inches. The fourth and fifth teeth of the 

 right side of this rare anatomical specimen are absent. 

 Perhaps they were carious. The rarefied and spongy 

 tissue of the socket-bones indicate the seat of an alter- 

 ation — probably caries — which was the point of depar- 

 ture of the general tumefaction. The last tooth, by 

 its oblique direction toward the empty sockets, indi- 

 cates that the loss of the teeth occurred during the life 

 of the animal, some time perhaps prior to its death. 

 The defect of the right side doubtless forced the ani- 

 mal to use the left for the purposes of mastication. In 

 such cases the teeth that do not wear grow till they 

 reach their respective opposite jaws, even when those 

 at the opposite side of the mouth are in exact con- 

 tact, an anomaly never produced in the normal state. 

 The function of mastication operates according to the 

 obliquity of contact, and a parallelism is estabhshed 

 by friction between the tables which normally would 

 be superposed. 



" This appears to us to be the only interpretation of 

 the facts, and we have observed two analogous exam- 

 ples in hving horses, but we did not think to ascertain 

 whether the deformity of an entire arcade was owing 

 to defect of a grinder or to disease of the bone. The 

 solution of the question would be an important acqui- 

 sition to the science of dental pathology, 



" (B.) There is another kind of deformity of the 

 arcades not very uncommon. The lower teeth wear 



