512 Tuberculosis. 



following the administration- of large masses of virus is 

 ascribed to the same cause since no tubercles develop in the 

 body. The same is true of the excessive irritation, fever, 

 suppuration at the point of injection and the temporary swell- 

 ing of the regional lymph glands which are observed after the 

 subcutaneous administration of avian tubercle bacilli in cattle 

 (Kossel, Weber & Heuss). 



Anatomical Changes. On post-mortem examination the 

 liver and spleen are most frequently found affected and this 

 is not rarely the case when the intestine and peritoneum are 

 entirely free from changes. As a rule there are nodules rang- 

 ing in size from that, of a lentil to that of a pea, and some- 

 times approaching that of a hazelnut, with colorless, gelatinous 

 or yellowish, friable, cheesy and occasionally calcified contents 

 and surrounded or enclosed by a connective tissue capsule. In 

 rare cases minute gray or pale yellow points, here and there 

 collected into groups under the serosa, are scattered through 

 the tissue of the liver. The diseased liver, especially in chronic 

 cases, is considerably enlarged and may be rather friable on 

 account of fatty, degeneration. Now and then hemorrhagic 

 areas occur near the surface of the organ. 



Affection of the intestine, especially near the cecums, is 

 comparatively common. The mucous membrane is covered 

 with small yellowish nodules among which funnel-shaped ulcers 

 with finely nodulated or raised borders may be present. On 

 the serous ^surface there may be firmly attached coarsely 

 nodulated roundish tumors that may approach the size of a 

 hazelnut. These may also occur in the mesentery (Fig. 96). 

 These tumors or nodes may have a wide or narrow base or 

 they may be pedunculated, but they are always clearly differen- 

 tiated from the surrounding tissue and covered by peritoneum. 

 The interior of the small nodules consists of a homogeneous 

 grayish-yellow, tough, almost hornlike or cartilaginous tissue, 

 while in the larger nodules, which are otherwise of similar 

 structure, there are also cheesy foci, or the nodules may con- 

 sist throughout of a yellowish, crumbly substance^ The interior 

 of these nodules may communicate, at the apex, with the lumen 

 of the intestine by means of a fistulous canal ( Volkmann found, 

 at the end of the left cecum, a cheesy tumor of the size of 

 a hen's egg; the remaining portion of the cecum was thickened 

 and covered with nodules). The abdominal lymphatic glands 

 are much enlarged and caseated. In a few cases the visceral 

 layer of the peritoneum is covered with nodules. 



In tuberculosis of the bones and joiiits, which is rather 

 common, the articular cavities are filled with cheesy masses; 

 the cartilaginous covering of the enlarged epiphyses shows 

 erosions while the bone substance and, occasionally the peri- 

 articular connective tissue contains cheesy foci. 



Tuberculosis of the lungs is much less frequent. Tlieso 

 may present the picture of a miliary tuberculosis or their 



