240 OVINE CASEOUS LYMPH-ADENITIS 



extensive adhesions and also effusions into the pleural cavities. 



In the liver the lesions consist largely of nodules com- 

 posed like those in the lymphatic glands, of a firm white 

 fibrous sac containing a greenish-yellow, cheesy mass of vary- 

 ing consistency. Cases have been reported, however, where 

 the entire organ was filled with miliary nodules. 



The kidneys are rarely affected, but when they are the 

 lesions assume the same characteristic appearance of a firm 

 walled abscess protruding on the surface of the organ. As a 

 rule, ouly one or two such foci are observed in each case. 



A histological examination of tissues containing miliary or 

 sub-miliary nodules, shows them to be composed chiefly of 

 leucocytes and nucleated round cells, the greater part of which 

 are irregular in shape, especially toward the center where 

 many of them are transformed into a granular detritus. 

 Among the cells arranged singly or in clumps, are seen the 

 short bacteria which stain irregularly. The shape varies con- 

 siderably from oval or oblong to a dumb-bell shape. 



The bacteria are frequently seen within the degenerated 

 leucocytes, the destruction of which is due, according to 

 Preisz, to the specific chemical products elaborated by these 

 microorganisms. 



The microscopic appearance is somewhat similar in all the 

 lesions whether located in the lymph glands, lungs, liver, kid- 

 neys or spleen. In the lungs the histological picture resem- 

 bles that of broncho-pneumonia. In the liver the lesions 

 originate in the portal capillaries, where the bacteria cause a 

 proliferation of the endothelial cells, which, together with the 

 accumulation of leucocytes and red corpuscles, cause the obli- 

 teration of the vessels. In no case have giant cells been ob- 

 served. The surrounding hepatic cells become swollen, then 

 granular, and finally they undergo atrophy, leaving open 

 spaces between them. Numerous round cells appear in the 

 periphery of the nodules, which gradually undergo a connec- 

 tive tissue metamorphosis and become organized into an en- 

 capsulating membrane. 



When a miliary nodule from the liver of an experimental 



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