126 HEALTH AND DISEASE 



ULCERS 



There are two varieties of ulcers as properly understood, viz. the 

 simple or common ulcer and the specific or infective. The former is due 

 to some local derangement of nutrition, the consequence of impaired 

 circulation or innervation of the parts. The latter results from the 

 action of specific organisms which have gained access to the body. The 

 non-infective ulcer assumes a variety of forms, of which the following are 

 of special interest to the veterinarian and the horse-owner. 



The Simple Ulcer is a sore in which the process of healing has 

 been arrested and followed by a more or less rapid extension of the 

 wound. A number of causes may be individually or collectively concerned 

 in bringing about this retrograde action. Among them the chief are 

 mechanical irritation, as the chafing of a collar or a saddle, or any other 

 part of the harness; undue movement of the injured part, such as 

 occurs when the wound is situated on the aspect of flexion or extension 

 of a joint, or over the seat of much-used muscles. It may also be induced 

 by pressure. 



Ulcers of this kind are covered with yellowish-red granulations, which 

 are usually flush with the margin of the skin, and the edges are but 

 slightly if at all thickened. 



When severely irritated, acute inflammation is excited in these ulcers,, 

 and the surrounding skin becomes thickened by serous infiltration; there 

 is also great soreness, and a free discharge of pus from the surface. 

 The edges of the wound now present a somewhat irregular and sloughy 

 appearance. 



The Indolent or Callous Ulcer. — The callous ulcer is most fre- 

 quently found on the shoulders and backs of old horses as the result of 

 ill-fitting collars and saddles, or on the withers, or in the heels. It is 

 usually preceded by a succession of abrasions, during which the skin and 

 subcutaneous tissues become infiltrated and thickened, and the vessels 

 surrounded and compressed by a contracting undergrowth. As a conse- 

 quence the blood-supply to the part is diminished, its vitality is weakened, 

 and the skin is predisposed to ulcei'ate. 



The callous ulcer is more or less hollowed and like a saucer. The 

 edges are thickened, and raised above the general surface, which is usually 

 smooth, and of a pale-yellowish colour. It discharges a small quantity of 

 thin, sero-purulent fluid, and shows little or no disposition to throw up 

 granulations. The skin round and about the wound, and the tissue beneath 

 it, are hard and thickened, and firmly adherent to the underlying parts. 



