DISEASE OF ALVEOLAR PROCESSES. 167 



it, there can be no doubt. For example, the teeth be- 

 ing placed at a distance from each other, thereby allow- 

 ing the food to lodge between them, must be looked 

 upon as a predisposing cause. A strumous diathesis, 

 which I believe to be more common in the horse than 

 is usually supposed, must also be regarded as a predis- 

 posing cause. The particles of food which become 

 impacted in these unusually wide interdental spaces, 

 after a time decompose and give rise to fetid com- 

 pounds, which act prejudicially on the parts they are in 

 contact with. The membrane which covers the gums, 

 and also that which lines the alveoli and is reflected 

 on the roots of the teeth, becomes inflamed. The 

 inflammation will extend to the bone, the blood-vessels 

 of which will become enlarged, as will also the Haver- 

 sian canals in which they ramify. The osseous laminae 

 surrounding these canals will be partially absorbed, 

 and to some extent separated from each other, and the 

 enlarged spaces thus produced will be filled with in- 

 flammatory exudation. Hence the soft, spongy state 

 of the gums and their tendency to bleed from slight 

 causes ; hence also the looseness of the teeth in the 

 alveoli." 



Of the deformity called Parrot-Mouth, and irregular- 

 ities of the incisor teeth, Prof. Varnell says: 



" This deformity consists in the upper incisor teeth 

 projecting in front of and overhanging the lower ones 

 to the extent in some instances of an inch and a half. 

 The deformity resembles the upper bill of the parrot, 

 which projects over the lower ; hence the name. The 

 lower incisors, from not being worn off by attrition, 

 may become so long that the roof of the mouth is seri- 

 ously injured. The deformity is generally associated 



