OPERATIONS ON THE SKULL, FACE, LIPS, ETC. 



99 



during the next few days, and to keep the wound open, but 

 as a general rule this is not necessary. 



The illustration (Fig. 70) here shown represents the left 

 upper fourth premolar extracted from a small Welsh terrier, 

 the subject of pus in the antrum, for the sketch and technical 

 description of which I am indebted to Mr. Charles Tomes, 

 F.R.C.S. (author of ' Dental Anatom\- ). 



' The crown of the tooth presents nothing unusual, and has been 

 exposed to little wear. All three roots show sig-ns of inflammation of 

 some standing-, and are reduced by absorption 

 consequent upon the inflammation. The outer 

 external root, seen to the left of the figure, is 

 not much shortened, but its apical portion is 

 thinned down so that it terminates in a sharp 

 point. The antero-internal root, imperfectly seen 

 behind the other in the figure, is more shortened, /" "' «^'" 

 and terminates in a sharp-edged crater, very 

 characteristic of absorption. The posterior root -'Sa ., V) 



at the right of the figure is more interesting ; it ' 



is thinned, shortened and roughened by absorp- 

 tion, and two cracks run across it — the upper one Fig. 70. — Left Upper 

 widely open, and the lower one with its edges in Fourth Premolar, 

 apposition. These edges have been attacked by showing Result of 

 absorption, and to some extent excavated and Fracture and In- 

 rounded. There is not the least doubt that the flaramation of the 

 incomplete fracture of the root took place weeks. Fangs, 

 and probably a good many months, before it 



was e.xtracted. The probable history is that the dog broke the root partly 

 through in biting a bone, and that the irritation caused by the fracture 

 set up absorption, not only in the damaged root, but also, to a less 

 extent, in the other two undamaged roots, the periosteum of which may 

 well have suffered minor injury by the wrench. Probably the tooth pulp 

 was killed by, or died subsequently to, the accident, though this cannot 

 be ascertained from the specimen. Its death and decomposition would 

 account for the suppuration above its root.'^ 



Tumours. 



Tumours of the brain of the dog are rare, and their 

 satisfactory removal whilst the patient is alive is usually a 

 1 \'eterinary Jniirnal, vol. Ix., p. 137. 



7—2 



