The Head and Neck 



89 



bilateral through sympathy and may give rise to a symptomatic ca- 

 tarrhal inflammation of the nasal passages through contiguity of 

 tissue. The sympathetic 

 hypothesis is very doubt- 

 ful.. 



Symptoms and Diag- 

 nosis. A fistula existing 

 in the position mentioned, 

 should be probed. The 

 affected tooth can gener- 

 ally be determined in this 

 manner. The tooth may 

 or may not be painful to 

 percussion. Maxillary fis- 

 tula must be carefully differentiated from Lachrymal fistula. An 

 animal suffering from the former disease masticates with difficulty 

 and prefers a semi-solid or liquid diet. In some cases the progress 

 of the disease is accompanied with much emaciation. 



Treatment. The tooth belonging to the affected alveolus must 

 be removed, and the fistulous tract irrigated. Recovery is usually 

 quick to ensue. 



No. 30. MaxlUarr fistula. 



CARIES. 



True decay of the teeth with molecular disintegration of the 

 constituent dental tissues, from which mankind so conspicuously suf- 

 fers, is exceedingly rare in the dog. It has been observed by Baume 

 Moeller, and Hoffman. The disintegration always commences on 

 the surface of the tooth, generally in some pit or crevice in the 

 enamel or at the neck, where protection from the movements of the 

 tongue as well as from the friction produced by the gnawing of hard 

 foodstuffs, bones, etc., favors the lodgment of alimentary particles 

 The degenerative process having commenced (the spot may or may 

 not be marked by a dark color) it spreads towards the interior of the 

 tooth, and the dentine being more susceptible to its action than the 

 enamel, a cavity is formed whose interior is larger than its orifice, 

 This disease must not be confounded with pericementitis which is 

 very common. 



The observations of Miller have established the fact that the 

 degenerative process is due to a direct chemical cause, food par- 



