194 



VETERINARY STUDIES 



in a small lymph gland to a general invasion of lungs, liver, 

 kidneys, mesenteric glands, peritoneum, and pleura. 



Sjmiptoms. — These vary according to extent and location of 

 the disease and are in general unreliable and indefinite. A 

 few cases become thin and rough in appearance, have a chronic 

 cough or chronic diarrhea, and show general debility. The great 

 majority show no symptoms, and may appear to be in the 

 finest possible physical condition. There are a great many 



Fig. 67. — Bovine Tuberculosis. (M. H. E.) 



A great variety of tubercles on the chest lining (costal pleura). Sternum 

 below, broken ribs above. 



mild or latent cases, having but a small amount of diseased 

 tissue, and the animals may live for many years in apparently 

 good condition. On the other hand, they may succumb to a 

 sudden development of the disease following any condition 

 which produces debility. 



When the lu7igs are involved, there may be a loersistent 

 cough, shortness of breath, pallor of visible mucous membranes, 

 loss of flesh, and unusual sounds in the lungs. 



When intestines and mesenteric glands are affected, there 

 may be chronic diarrhea with slow and persistent loss of con- 

 dition. All these diagnostic symptoms may vary greatly and 

 are often unreliable; e.g., a cow may be in good flesh, her hair 



