13& THE PATHOLOGY OF* THE TEETH. 



" Odontonecrosis " is defined by him as " dental gan- 

 grene/' and "Odontrypy" as "the operation of perfo- 

 rating a tooth to evacuate the purulent matter con- 

 fined in the cavity of the pulp" (pulpal cavity). 



Prof. William Percivall, referring to two diseased 

 grinder teeth (horses'), says: 



" They seemed to have been cases which had origi- 

 nated in internal injury." 



Surgeons Bouley and Ferguson say: 



"In explaining caries of the teeth, we cannot invoke 

 the aid of inflammation and the modifications which 

 it induces in the tissues it attacks; nor can we say 

 that inflammation implies an active circulatory move- 

 ment, an afflux of liquid, an alteration, nervous de- 

 rangement, &c." 



Possibly the gentlemen were not aware of the in- 

 flammation that Prof. Owen says may exist "in the 

 original formative pulp," and of that of "the pulpal 

 cavity" the pulp in the cavity of a full-grown tooth 

 mentioned by Drs. Hayes and Dunglison. Are not 

 such inflammations liable to be produced by colds or 

 violent shocks? 



Prof. George Varnell, who believes caries of the roots 

 of horses' teeth is usually caused by external violence, 



"Inflammation of the alveolo-dental periosteum 

 would tend to this result (caries of the roots). When 

 the nutrition of any part of a tooth becomes arrested, 

 decay is likely to follow. When caries begins from 

 within, it is due to arrestation of nutrition, arising 

 perhaps from disease of only a part of the central pulp 



