396 CHRONIC INFECTIOUS DISEASES 



nective tissue and new-formed bloodvessels, where they case- 

 ate and calcify. By confluence great polypoid masses several 

 centimeters thick occur, appearing not unlike a bunch of 

 grapes, hence the old name "grape disease." Not infre- 

 quently these nodular protuberances will involve the peri- 

 cardium and epicardium, leading to adhesion between them. 

 The endocardium and valves of the heart are rarely involved. 



Lymph Glands. — The lymph glands corresponding to the 

 affected organ are almost always tuberculous. Not infre- 

 quently only the lymph glands are diseased. This is espe- 

 cially true in young animals in the earlier stages of the disease, 

 and in older individuals condemned by the tuberculin test. 

 In some cases the lymph glands on the surface of the body, 

 particularly the submaxillary, subauricular, prescapular, and 

 precrural are involved. In other infections the- supramam- 

 mary glands are elected. The tuberculous lymph gland is 

 often enlarged to many times its normal size and presents a 

 nodular surface. On section it will be found to contain 

 tubercles which appear either as round or irregular-shaped 

 radiating areas of caseation, sometimes surrounded by a 

 capsule of connective tissue, and often calcified. In pul- 

 monary tuberculosis especially the mediastinal and peribron- 

 chial lymph glands are diseased. In the digestive tract the 

 suprapharyngeal, mesenteric, and portal lymph glands are 

 elected. The glands may attain the size of a double clenched 

 fist, and in some instances interfere with the functions of 

 organs with which they come in contact. Partial occlusion 

 of the esophagus when mediastinal lymph glands are involved 

 is often observed. The mucous membrane of the digestive 

 tract may show nodules or ulcers. As a rule the borders of 

 the tubercular ulcer are thickened and the base caseous. 

 They extend into the submucosa or muscularis. Usually the 

 environing mucous membrane is thickened and catarrhally 

 inflamed. 



Liver. — Besides tuberculosis of the peritoneum covering the 

 liver, in the parenchyma of the organ small tubercles or 

 larger, dry, caseous or softer, puriform areas are noted. As 

 a rule the nodes and abscesses are surrounded by connective- 

 tissue capsules. In some instances from connective-tissue 



Digitized by Microsoft® 



