370 



VETERINARY PATHOLOGY. 



may involve all those parts. The inflammatory disturbance stim- 

 ulates or is accompanied by a proliferation of epithelial cells in 

 the eye, nose, mouth or even on the wattles and comb. These 

 epithelial new growths are at first grayish, have a smooth, glis- 

 tening appearance and are surrounded by a hyperaemic zone. 

 Later the growths, which become nodular, undergo degenera- 

 tion, especiallv upon the surface. The necrotic tissue may re- 

 main and form a scab or it may slough leaving a ragged, brown- 





Fig, 203. 

 T.eft side of liead, showing vyv with extensive accumulation of cas<.'Ous necrotic 



material. 



i.-^h or grayisli indurated surface. These nodules may become 

 as large as a pigeon's eg^. Thev frequently entirely obstruct 

 vision and in some cases destroy the eye ; those appearing in 

 the nostril may seriously interfere with respiration or even 

 obstruct tlie air passages ; and nodules in the buccal cavity may 

 prevent eating or the prehension of food ; while those that occur 

 in or upon the wattles and comb may be so extensive that 

 these structures are practically destroyed. These nodules may 

 entirely luidergo necrosis, the necrotic tissue becoming dry 

 and scaly or necrosis may begin in the center of the 

 nodule and be of a liquefying character and when the entire 

 nodule has undergone necrosis the mass is discharged as a 

 thick, watery fluid containing flakes of coagulated necrotic tis- 

 sue. Again the discharge may be thick and creamy or it may even 

 be of a caseous nature. 



