ULCERS AED FISTUL.E. 301 



bth. The ^phagedenic, gangrenous, or sloughing ulcer, which may 

 arise from constitutional debility or from local causes, as frost-bites, is 

 that in which the edges are very irregular, and of a dark purple appearance, 

 extending a considerable way into the surrounding parts; they are often 

 inverted, and exceedingly painful. The surface of the ulcer is uneven, 

 of a dark, livid color, presenting a very irritable appearance and much 

 surrounding swelling. The discharge is thin, ichorous, and mixed with 

 blood. The ulcer enlarges with great rapidity, the destructive process 

 being carried on both by ulceration and sloughing. In some cases many 

 points of ulceration form in the neighborhood of each other, the ulcera- 

 tion taking place around several central sloughs; these by enlargement 

 coalesce, and ultimately form one large ulcer, embracing, as in some 

 cases of " carbuncle of the coronary band," a space of several inches. 

 The treatment of this variety is a matter of great urgency and import- 

 ance, but not always satisfactory. 



Treatment. — Free scarifications of the part, to relieve congestion; 

 the removal of all sources of irritation, and the application of emollient 

 and antiseptic poultices or fomentations, constitute the best local treat- 

 ment. If the ulceration continues to spread, the gentle application of 

 nitrate of silver to the edges may benefit. The constitutional derange- 

 ment must be treated by purgatives, anodynes, or sedatives, succeeded 

 by tonics; and the diet regulated according to the stage and variety of 

 the accompanying symptoms. 



POLL-EVIL. 



Definition. — This is a fistulous ulcer situated on the supero-posterior 

 portion of the cranium immediately behind the ears of the horse, and is 

 caused by accidental violence, or by the habitual use of a tight bearing- 

 rein. 



At the first stage it may be recognized as a soft fluctuating tumor sur- 

 rounded by inflammatory swelling, enlargement of the superior cervical 

 lymphatics, and stiffness of the neck; or the inflammation of the sur- 

 rounding tissue may have subsided, leaving a prominent swelling — a se- 

 rous abscess. 



From the peculiar position of the injury, the matter has no depending 



