150 BOVINE PATHOLOGY. 



tlie tongue. The altered epithelium, when thrown off or 

 removed, passes out of the system with the profuse dis- 

 charge of saliva. After the mucous membrane of the 

 vulva becomes of a very dark purple colour, the epithelium 

 undergoes changes similar to that of the mouth, and there 

 is an albuminous discharge, which hangs from the lower 

 commissure. The Schneiderian membrane, after exhibiting 

 the early congested condition, becomes pale, petechiated, 

 and its blood-vessels are very evident ; then its epithelium 

 becomes altered. There is a discharge which hangs about 

 the nostrils and dries there. The skin is involved in 

 diseased action ; the parts covering the udder, teats, 

 inside of the thighs, and those neighbouring the mucous 

 membranes are especially affected, though we often see 

 the general surface implicated. In the male the praeputial 

 membrane and the scrotum are very liable to become 

 affected. The lesion may range from a scurfy condition, 

 through a papular stage to the pustular, exudations taking 

 place which mat the hairs together, or the pustules become 

 confluent, and form brown patches of a considerable size. 



Prognosis. — Williams says : — '' Some cases of cattle 

 plague recover, and in these cases it is observed that 

 the skin over the neck, withers, &c., becomes covered 

 with a yellowish sebaceous secretion, but there are no 

 vesicles or pustules.'^ It is found that recovery from one 

 attack secures future immunity. It must be remembered, 

 however, that an animal himself exempt may convey the 

 contagium. The complications of this disorder, altera- 

 tions of the intestinal mucous membrane, persistent diar- 

 rhoea, and excessive debility, are such as prevent frequent 

 recovery ; but in its enzootic abode many mild cases are 

 seen. No known race of cattle is exempt, but it is said 

 that animals native to the districts whence it comes can 

 resist its influence much more frequently than others. 

 Some few animals enjoy immunity during an attack even 

 in Western Europe. 



Causes. — The climatic and hygienic conditions of 

 animals in the enzootic abode of this disorder are pecu- 

 liarly trying to the constitution. Drought, starvation 



