SURGICAL OPERATIONS. 267 



separate from its cellular connections a circle of two or three mche9 

 in diameter, into which introduce something to prevent the reunioi? 

 of the skin. A piece of circular leather, tolerably stiff, with a cen- 

 tral hole, is a very common substance used, but is objected to by 

 some on account of the difficulty of changing it without injuring 

 the skin. Tow, as more pliant, is frequently introduced into this 

 cavity. If the rowel runs freely, it should be dressed every day, 

 by changing the plug, if of tow, and by cleansing it, if of leather. 

 No rowel should go undressed beyond the second day, for the com- 

 fort of the horse. They are very favorite applications with far- 

 riers, and frequently abused by being employed indiscriminately, 

 but are falling into disuse, setons having almost superseded them. 

 Setons, in their action, resemble a very mild form of rowel, but 

 are more convenient in their application. There is hardly a part 

 of the body where a seton may not be conveniently placed. They 

 have been put around the eye ; they have also been entered at the 

 withers, and brought out between the humerus and the sternum, 

 so extensive or so diminutive can they be made. In sinuous ulcers 

 of the withers and of the neck they may be placed ; through the 

 heels, in foot diseases, they have been inserted. In cavernous 

 sores, they are entered at the superior part, and are brought out at 

 an inferior, so as to form a depending orifice. The formation of a 

 seton is very simple. A skein of thread, or a piece of tape, of a 

 convenient size, may be used. At the one end place a large knot ; 

 arm the eye of a corresponding-sized seton-needle with the free end 

 of the tape ; introduce this into any proposed part, and, bringing 

 it out at some other, either make a second knot, or tie the two ends 

 of the tape together ; which last method of fastening is, however, 

 often objected to, from the danger of its catching in something and 

 being torn out, to the disfigurement of the horse. AVhen a seton 

 is placed in a sinuous track, for the purpose of inflaming, it is 

 moved twice a day, frequently, and moistened each time with 

 some stimulant, as oil of turpentine, tincture of aloes and of ben- 

 jamin. All setons require daily cleaning and moving. When 

 ihey are required to act more quickly, the tape is infused in tere- 

 binthinate of cantharides, or small pieces of black hellebore are 

 sewn within it. An old material, composed of woollen, flax, o^ 

 cotton and hair, is also used instead of tape. Setons, however, 

 are of small service in acute cases. They are chiefly in use for 

 disturbance of a chronic description. 



