13 



TUBERCULOSIS. 



Definition. — A contagious disease caused by a microbe — 

 tl)e bacillus tuberculosis. 



Animals affected. — Human beings and most species of mam- 

 mals and birds are liable to tuberculosis. Among-st the domesti- 

 cated animals cattle, i)articularly dairy cows, and swine are most 

 frequently iititH-ted; siieei) very rarely. 



Symptovis. — Sometimes not cliaracteristic, the disease being- 

 often of a mild chronic nature. In advanced cases there is usually 

 emaciation, when the lungs are affected there may be a chronic 

 cough with disturbance of the respiratory function. In cows 

 lesions in connection with the udder are sometimes present. Tlie 

 udder, usually in one of the posterior cjuarters, becomes the seat 

 of a hard swelling- of slow but steadily progressive growth — th*» 

 swelling is usually almost painless. 



The milk from the affected quarter at first appears normal, 

 then becomes thin and watery, and later becomes flaked. Micro- 

 scopic examination of milk from the diseased quarter shows the 

 presence of tubercle bacilli. 



During life the existence of the disease may be detected by 

 means of the tuberculin test. 



Post-morfeni . — The characteristic lesion caused by the tuberch. 

 bacillus is a particular form of degeneration called caseation. 

 The tissue affected becomes converted into a cheesy mass. 

 Nodules of varying size may be present in the lungs, liver, 

 kidneys, in lymphatic glands in various parts of the body, in the 

 uterus, udder, pleura, peritoneum, membranes of the brain, etc. 



Board of Agriculture and Fisheries, 

 4, Whitehall Place, 

 London, S.W. 



August, una. 



(.^1296—9.-) Wt. 17865— 35. 37r.. 8M3. DAS. 



