340 VETERINARY SURGICAL OPERATIONS 



to widen the tract and estimate its capacity by passing a 

 smooth, flexible sound to its remotest part, or as far as pos- 

 sible. A torturous tract may be difficult to follow, and to 

 facilitate matters it may be necessary to enlarge the orifice 

 and direct the sound by placing the hand in the rectum, 

 whereby a corrected impression of its course and progress 

 can be determined. 



Having thus explored the tract and having estimated its 

 capacity, a mixture of paraffin, 95% and subnitrate of bis- 

 muth 5% melted into a liquid is injected into it at 112 degrees 

 Fahr., until the capacity of the cavity is fully taxed. An all 

 metal syringe, of sufficient size to hold all of the liquid re- 

 quired, is employed for the purpose, in order that the opera- 

 tion may be completed in a single injection. The mixture 

 must be injected with considerable force so that it will flow 

 to the remotest part of the. tract before it hardens, and the 

 syringe must be heated to prevent the mixture from hard- 

 ening within it. 



No after-care is required, and unless the tract leads into 

 a large abscess cavity cicatrization will usually follow forth- 

 with. 



Operation for Cervical Fistula. 



I1\T DlCATIONS— By "cervical fistula" is meant a puru- 

 lent fistula located in the cervical region at some point be- 

 tween the withers and the poll. They are usually located in 

 the lower third of the neck and generally below the level of 

 the cordiform portion of the Hgamentum nuchas. The cen- 

 ter of the disease is between the two lateral groups of the 

 superior cervical muscles related to the lamellar portion of 

 the ligament and bodies of the vertebra. The perpetuat- 

 ing cause is the necrosis which the ligament has undergone. 

 The tracts may point on one or both sides, but in every case 

 the disease itself is central. 



TECHNIQUE.— The operation against this fistula is 

 best performed in the standing posture because the normal 

 relations of the anatomical structure are thus maintained. 

 Stocks are much the best. 



After cleansing the region on both sides in the usual 

 manner an oblique incision about four inches long, parallel- 

 ing the line of the vertebral column, is made on one side of 

 the neck slightly below the supposed location of .the necrotic 

 center, which is usually about two inches above the ver- 

 tebra. It is carried inward through the perfectly healthy 

 muscles to the lamellar portion of the ligament. Then, after 



