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become cohesive and sticky and of the consistency 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 by Oesophagostoma Columbianum . In very advanced 

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



Fig. 58. Lung of sheep studded with nodules ( Gilrwth) . 



organs may contain lesions which microscopically resemble 

 those of tuberculosis. The lungs may be studded with small 

 nodulesthesizeof a pea, the spleen, liver and in rare instances 

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

 character, namely, a mass of greenish yellow material, sur- 

 rounded by a firm, fibrous wall. There seems, however, to be 

 a distinct line of demarcation between the affected and the 

 healthy tissue. 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 ex- 

 tensively involved. The lesions consist of nodules varying in 

 size trom that of a millet seed to that of a walnut. This con- 

 dition is, as a rule, accompanied by a chronic pleurisy with 



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