General Surgery 31 



the sore from any kind of irritation, wiiether it be by the animal's 

 own teeth, or from accumulated discharges. Healthy ulcers require 

 soothing treatment by , means of dessicant antiseptic powders. On 

 external parts they should always be protected with gauze and band- 

 ages, though this is often a difficult matter to accomplish, owing to 

 the persistence with which any kind of application and even muzzles 

 are torn off. Indolent ulcers require gentle stimulation with weak 

 distilled aqueous solutions of nitrate of silver (4:100) before the 

 powder is used. Exuberant ulcers should be cauterized with the 

 solid nitrate of silver stick or the actual cautery. Drainage must be 

 provided for discharges where there is a tendency to accumulation. 

 The general health should be attended to, laxatives and tonics being 

 administered when the nutrition of the body is at fault. The ulcera- 

 tion of malignant tumors can only be treated by eradication of the 

 growth. 



FISTULA. SINUS. 



A fistula or sinus is any abnormal tract in the tissues forming a 

 communication between a septic focus or secreting gland and any 

 other part of the body, either the surface or a natural cavity or canal. 

 The term fistula is applied when the tract is open at both ends and 

 the term sinus when it is open only at one end. The great majority 

 of sinuses arise from abscesses which do not close up by granulation, 

 and their failure to close is usually due to the presence of a foreign 

 body or dead bone, but may also be due to protracted discharge 

 bringing about induration of the tissues in the line of evacuation, 

 and in rare cases to tubercular disease and actinomycosis. Occasion- 

 ally fistulae originate as congenital defects. Where the tract com- 

 municates with a secreting gland, the secretion itself independent of 

 any septic process may be sufficient to inhibit the healing process. 



Treatment. The first step is to seek the cause. If a foreign 

 body be present, steps must be taken to remove it. Dead bone must 

 also be displaced. Next, the wall should be curetted or stimulated 

 by injections of strong distilled aqueous solutions of nitrate of sil- 

 ver (5:100 — 10:100). Failing in this, the tract must be laid freely 

 open, the lining membrane cut away, and the wound packed with 

 antiseptic gauze so that healing may proceed from the bottom. 

 Where it is considered inadvisable to open up the tract by reason of 



