548 PRINCIPLES OF VETERINARY SURGERY 



tumor retains the hair, and is only destitute ,of it in the 

 perineum, inferior surface of the tail, etc. — L. A. M.J They 

 may become soft, fluctuating or ulcerated, in which case 

 they discharge a thick, dirty liquid, of the color of blacking. 



SYMPTOMS. — There is no symptomatic tableau more 

 varied than that of melanosis. Every structure, every or- 

 gan in the system, may be invaded with melanotic infiltra- 

 tion. Every function may be disturbed, mechanically im- 

 peded, or suppressed by deposits of pigmentary tumors. 

 Only the principal localizations can, therefore, be re- 

 viewed (B^ig. 68). The skin and the subcutaneous connec- 

 tive tissue are sometimes the seat of semi-lunar or ovoid 

 tumors of variable sizes on the lateral surfaces of the neck 

 and shoulders, at the collar, seat, in the costal region, etc. 

 Generally they accumulate in the region of the tail, the rec- 

 tum, vulva, or prepuce. Isolated in groups, they have their 

 limits well defined. They are hard, elastic, sluggish and 

 without any peripheric inflammatory infiltration, character- 

 istic of phlegmons in the course of development. 



When numerous around the anus, they first present 

 rounded outlines, but sooner or later fuse together, acqviire 

 considerable dimensions, and become the seat of inflarAma- 

 tions occasioned by the crupper (Fig. 68a). When thus in- 

 jured, they may soften, fluctuate and even ulcerate, but the 

 discharge of black substance, the existence of other tumors 

 and the pigmentary infiltration of the surrounding parts 

 disclose the origin of these pseudo-purulent foci. Cica- 

 trization is slow; the anatomical elements, incumbered with 

 pigment, find difficulty in regenerating. The external 

 melanotic infiltrations are accompanied, also, by numerous 

 functional disturbances. Melanosis of the rectum and 

 vagina, although compatible with health for a long time, 

 generally ends by deforming these orifices and impedes the 

 exit of excrements. The walls of the vagina and rectum 



