56 MANUAL OF EQUINE MEDICINE. 



appetite is impaired, and there is marked debility and 

 emaciation. Tlie Schneiderian membrane varies in colour 

 from a light to a dark brown, and the other visible mucous 

 membranes are highly congested. 



In a few days (three to six) the febrile symptoms abate, 

 returning again after a variable period of remission, during 

 which the characteristic local lesions are developed. The 

 pituitary membrane, especially that of the nasal septum 

 and of the alse, becomes studded with small tubercular 

 nodules arranged in groups, or more generally diffused over 

 the surface of the mucous membrane. When, as sometimes 

 occurs, the subjacent tissue of the latter is much infiltrated, 

 the patches become more prominent. 



The nodules vary in size from a small seed to a pea, and 

 appear as projections on an elevated base of congested 

 mucous membrane. They have a yellowish white centre, 

 surrounded by a greyish zone, round which is again a 

 reddish one. 



In a few days the diffuse patches and nodules gradually 

 soften, and ulceration commences in the central portions of 

 the latter. Thus, as the epithelium is removed, there is 

 produced a characteristic ulcer with irregularly excavated 

 borders. The floor and edges of the ulcer may become 

 studded with small nodules, and covered with prominent 

 vascular granulations. 



The ulcers gradually extend and coalesce with one another, 

 forming larger ones, which eat their way into the underlying 

 tissue, and even at times lead to necrosis of the nasal 

 septum. 



The above pathological changes also involve the larynx 

 and the mucous membrane of the sinuses of the head. The 

 discharge from the nose, which during the onset of the 

 febrile symptoms was yellowish and somewhat viscid, 

 becomes, as the nodules ulcerate, thick, gluey, and purulent. 



