94 VETERINARY SURGICAL OPERATIONS 



before the dead and the healthy parts have separated from 

 each other, or before the dead can be recognized from the 

 living, in which event the surgical wound will heal over at 

 the surface before the hot-bed of the disease (the necrotic 

 center) itself is ready for cicatrization, with the effect that 

 another abscess will point elsewhere and thus perpetuate 

 the identical condition for which the operation was per- 

 formed. In short the well nourished tissues (skin, muscle, 

 etc.) heal faster than the poorly nourished ones (bone, carti- 

 lage, ligaments, etc.) and therefore require something in the 

 form of a seton to delay their healing until cicatrization is 

 complete in the latter. In this connection setons perform 

 about the same function as the caustic, which likewise retards 

 healing of the well nourished, soft tissues while the underly- 

 ing causative lesion goes through its slow process of cicatri- 

 zation. 



RESTRAINT. — Subcutaneous setons for the most part 

 can be inserted with the patient in the standing position with 

 the aid of the twitch and the side-line. In deep fistulse of the 

 withers or similar conditions, especially in restive animals, 

 the recumbent position may be found necessary in order to 

 more effectually trace out the depths of the tracts with the 

 long needle, but besides these circumstances the upright 

 posture of the animal rather favors their exact adjustment. 

 Furthermore, the subject that is too restive to. endure the 

 pain of insertion is no fit subject for the operation, because 

 of the difficulty of properly caring for the setons and the field 

 thereafter. A docile animal is sometimes transformed into 

 an intractable fiend by the pain inflicted in necessary turning 

 of the setons day after day, hence the advisability of avoiding 

 such treatment in other than perfectly tractable subjects. 



EQUIPMENT.— i. Seton needle. (Fig. 46.) 



2. Sterilized tape. 



3. Scalpel or roweling scissors. 



4. Clippers and razor. 



5. Soap, water and antiseptic solution. 

 The seton needle for the application of subcutaneous 



setons to meet every ordinary requirement should be eigh- 

 teen inches long, and bendable so that it can be shaped to 

 follow the curves of the body. Its point should be sharp 

 and slightly curved outward in order to facilitate its passage 

 through the skin at any desired point by slightly pressing the 

 threaded end toward the body. Blunt-pointed needles are 

 sometimes preferable to sharp ones in tracing fistulous tracts 

 to a dependent part, owing to the likelihood of the latter leav- 



