164 OVINE CASEOUS LYMPH-ADENITIS 



ma}' be given as follows ; prescapular, precrural, superficial 

 inguinal, bronchial, mediastinal, sub-lumbar, deep inguinal, 

 and scrotal. Rarely the suprasternal and mesenteric glands 

 are affected. Sivori mentions the mesenteric glands among 

 those frequently affected. He fails, however, to mention the 

 mesenteric glands as the seat of lesions in the detailed descrip- 

 tion of twelve typical cases of caseous broncho-pneumonia 

 caused by the bacillus of Preisz. 



When first invaded by the bacterium, the adenoid tissue 

 becomes h^'perplastic and the gland enlarges to several times 

 its original size. On section, the surface is found to be watery 

 but otherwise the tissue retains its normal appearance. This 

 is followed by the formation of various centers of degeneration 

 which show concentric layers and graduall}- become confluent. 

 Finally, the total volume of the gland is transformed into a 

 homogeneous caseous mass. At the same time the distended 

 capsule increases in thickness and forms a sac which confines 

 the semifluid, grumous mass. In rare instances the sac rup- 

 tures and when close to the surface the contents will be dis- 

 charged. Under ordinary circumstances, the caseous contents 

 become cohesive and sticky and of the consistenc}' of putty. 

 In very old cases the mass becomes dry and mealy with little 

 or no tendency to calcification. The greenish yellow color of 

 the caseous mass, which is stated to be most characteristic, 

 closely resembles the contents of the intestinal nodules pro- 

 duced bj' Ocsophagostonia Colunibiaiuivi. In very advanced 

 cases, as for instance those of old bleeding ewes, the internal 

 organs may contain lesions which microscopically resemble 

 those of tuberculosis. The lungs may be studded with small 

 nodules the size of a pea, the spleen, liver and in rare in- 

 stances the kidneys also may contain one or more foci of the 

 same character, namely, a mass of greenish j'ellow material, 

 surrounded \>y a firm, fibrous sac. There seems, however, to 

 be a distinct line of demarcation between the affected and the 

 healthy tissue. There is no indication of an inflammatory zone. 

 The bronchial and the mediastinal glands may be affected to a 

 considerable extent without any lesions being found in the 

 lungs. In some cases the lungs are extensively involved. 



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