ACTINOMYCOSIS— LUMP JAW 413 



large cheesy areas. There is frequently also present an 

 adhesive pleuritis. The corresponding lymph glands may 

 be intact. In many cases the lesions are confined to the 

 external lymph glands, which are enlarged, and when incised 

 show greenish-yellow, sticky, smeary, cheesy masses often 

 arranged in concentric layers and surrounded by a capsule 

 of connective tissue. Often the caseous mass undergoes 

 partial calcification, changing it to a grayish-white, gypsum- 

 like mass. In rarer instances the abdominal organs are 

 involved, especially the liver, spleen and kidneys and more 

 rarely the mesenteric lymph glands. 



Symptoms. — The symptoms are rather vague. Most 

 cases are discovered in the slaughter house. Where the 

 affection involves superficial lymph glands, tumors appear 

 on the surface of the body, most frequently in the prescapular 

 and precrural regions. They are about the size of an average 

 potato and are not sensitive on palpation. The condition 

 of the sheep otherwise may be normal except that the 

 enlarged lymph glands may interfere with locomotion. 



When the lungs are affected the patient shows cough, 

 dyspnea, anemia, emaciation, and ultimately cachexia and 

 death. 



Course and Prognosis. — The course is prolonged, the disease 

 lasting for weeks or months with a gradual wasting of the 

 patient. The mortality varies but may reach, especially 

 among lambs, as high as 70 per cent. 



Treatment. — Medicinal treatment is of no avail. The 

 disease may be prevented to a certain extent by a thorough 

 disinfection of the navel immediately after birth and of 

 wounds, surgical and accidental. Vaccination has been 

 successfully practised, using an attenuated strain of the 

 ,bacilhis. When feasible the infected droppings should be 

 rendered innoxious by disinfection or removal to fields not 

 used for sheep. 



ACTINOMYCOSIS. LUMP JAW. 



Definition. — Actinomycosis is an infectious disease due to 

 a specific fungus and characterized clinically by the appear- 



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