SURGICAL OPERATIONS. 287 
separate from its cellular connections a circle of two or three inches 
in diameter, into which introduce something to prevent the reunion 
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 
3ome 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 dey, for the com- 
fort of the horse. They are very favorite applications with far- 
riers, and freqvently abused by being employed indiscriminately, 
but are falling inte disuse, setons having almost superseded them. 
Sedons, 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 arouna 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 
au 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. When a seten 
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 
they 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, or 
cotton and hair, is also used instead of tape. Setons, however, 
are of small service in acute cases. They are chiefly in use for 
disturbances of a chronic description. 
