476 DISEASES OF THE HORSE. 
The sitfast is a piece of dead tissue which would be thrown off but 
that it has formed firm connections with the fibrous skin beneath, or 
even deeper with the fibrous layers (fascia) of the muscles, or with 
the bones, and is thus bound in its place as a persistent source of irri- 
tation. The hornlike slough may thus involve the superficial part of 
the skin only, or the whole thickness of the skin, and even of scme of 
the structures beneath. The first object is to remove the dead irri- 
tant by dissecting it off with a sharp knife, after which the sore may 
be treated with simple wet clcths or a weak carbolic-acid lotion, like a 
common wound. If the outline of the dead mass is too indefinite, a 
linseed-meal poultice will make its outline more evident to the opera- 
tor. If the fascia or bone has become gangrenous, the dead portion 
must be removed with the hornlike skin. During and after treat- 
ment the horse must be kept at rest or the harness must be so adjusted 
that no pressure can come near the affected parts. (See also page 
496.) 
WARTS. 
These are essentially a morbid overgrowth of the superficial papil- 
lary layer of the skin and of the investing cuticular layer. They are 
mostly seen in young horses, about the lips, eyelids, cheeks, ears, 
beneath the belly, and on the sheath, but may develop anywhere. 
The smaller ones may be clipped off with scissors and the raw surface 
cauterized with bluestone. The larger may be sliced off with a sharp 
Imife, or if with a narrow neck they may be twisted off and then cau- 
terized. If very vascular they may be strangled by a wax thread or 
cord tied around their necks, at least three turns being made around 
and the ends being fixed by passing them beneath the last preceding 
turn of the cord, so that they can be tightened day by day as they 
slacken by shrinkage of the tissues. If the neck is too broad it may 
be transfixed several times with 4 double-threaded needle and then be 
tied in sections. Very broad warts that can not be treated in this 
way may be burned down with a soldering bolt at a red heat to 
beneath the surface of the skin, and any subsequent tendency to over- 
growth kept down bv bluestone. 
BLACK PIGMENT TUMORS, OR MELANOSIS. 
These are common in gray and in white horses on the naturally 
black parts of the skin at the roots of the'tail, around the anus, vulva, 
udder, sheath, eyelids, and lips. They are readily recognized by their 
inky-black color, which extends throughout the whole mass. They 
may appear as simple, pealike masses, or as multiple tumors aggre- 
gating many pounds, especially around the tail. In the horse these 
are usually simple tumors, and may be removed with the knife. In 
exceptional cases they prove cancerous, as they usually are in man. 
