476 DISEASES OF THE HOESE. 



The sitfast is a piece of dead tissue Avliicli would be thrown oft 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 thiclmess of the skin, and even of some 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 cloths 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 sldn. 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 overgroAvth of the superficial papil- 

 lary^ layer of the skin and of the investing cuticular laj^er. 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 

 knife, or if with a narrow neck they ma}^ be twisted off and then cau- 

 terized. If very vascular they may be strangled by a wax thread or 

 coi'd 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 b^' day as they 

 slacken by shrinkage of the tissues. If the neck is too broad it may 

 be transfixed several times with a 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 tlie skin, and any subsequent tendency to over- 

 growtli kept down by bluestone. 



BLACK PIGMENT TUMORS, OR MELANOSIS. 



These arc common in gray and in white horse- on the na,turally 

 black parts of the skin at the roots of the tail, around the anus, vulva, 

 udder, sheath, eyelids, and lips. They are readily i-ecognized by their 

 inky-black color, which extends throughout the Avhole 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 Avith the knife. In 

 exceptional cases they prove cancerous, as they usually are in man. 



