552 PRINCIPLES OF VETERINARY SURGERY 



infiltration of the tracliea, bronchial tubes and lungs is so 

 intense that the jugular, glossofacial and other superficial 

 veins are extremely distended. The pneumogastric the re- 

 current laryngeal and the phrenic nerves may be com- 

 pressed by melanotic masses. The trachea may be flat- 

 tened and almost obliterated and thus cause roaring that is 

 audible even in sleep, and even death from asphyxia. 



PROGRESS, DURATION, TERMINATION.— Mel- 

 anosis is compatible with health as long as it does not ob- 

 struct or suppress the functions. It is a benign affection 

 with a slow and chronic course and without any reverbera- 

 tion on the health. 



The acute forms [rare — L. A. M.J causing emaciation 

 and cachexia, with generalization of the. tumors, have an 

 undeniable cancerous character and do not belong to the 

 same category as simple melanosis. 



DIAGNOSIS. — The advanced age of the animal and 

 the coat [white — L. A. M.] facilitate the diagnosis. It does 

 not generally appear before the age of eight or ten years, 

 and simple melanosis is scarcely ever observed except in 

 white horses. Most of the melanoses observed in animals 

 of dark coats are fibromata, myxomata, carcinomata, or 

 sarcomata that are incidentally infiltrated with pigment. 



The absence of any inflammatory tumefaction and the 

 slowness of the development signalizes the nature of most 

 of the subcutaneous or intermuscular melanotic masses. 

 Besides, recourse may be had to puncture or incision of the 

 tumor to unmask its nature. The internal forms are re- 

 vealed by the functional disturbances accompanying them, 

 by the absence of fever, and by the presence of melanotic 

 nodules in the tail. 



PROGNOSIS. — The prognosis is comparatively grave, 

 by reason of the heredity of the disease, of the fact that 

 generalization is always possible, and of the numerous and 



