BOVINE TUBERCULOSIS. 



1SI 



disposing conditions undoubtedly have much to do with the de- 

 velopment of this disease; for instance, close confinement, lack 

 of ventilation and sunshine, injudicious inbreeding and inherited 

 susceptibility. 



Modes of entrance. — (i ) Lungs, with inhaled air; (2) 

 stomach and intestines, with food and drink; (3) by inoculation 

 through broken skin or mucous membrane ; (4) by infection in 

 utcro, i. e., before birth. This (4) is very rare and probably of 

 small importance compared with the others. 



FIG. 57. BOVINE TUBERCULOSIS. CI/. 11. Ii.) 

 A case showing plain symptoms of disease. Rare type. 



Structures affected. — Tuberculosis may affect any tissue or 

 organ of the body. Milk from tuberculous cows may be tubercu- 

 lous, but the danger is especially great when the udders are af- 

 fected. 



Extent of tissue diseased may vary from a few small lym- 

 phatic glands to a general invasion of lungs, liver, kidneys, mesen- 

 teric glands, peritoneum and pleura. 



Symptoms. — These vary according to extent and location of 

 the disease. A few cases become thin and rough in appearance, 

 and have chronic cough or chronic diarrhoea and show that they 



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