48 AGRICULTURE. 



nodules, and is due to a specific micro-organism, the bacillus 

 tuberculosis. 



Tuberculosis in animals is identical wit-h tuberculosis 

 (consumption) in the human family, the ravages of which 

 are far greater than those of any other disease. 



The death rate from consumption, which is but one of its 

 many forms, is about one in seven. 



All domestic animals are more or. less subject to the dis- 

 ease. Dairy cattle, however, in consequence of their mode 

 of life and the heavy drain on their system from excessive 

 breeding and milking, are more predisposed to the disease 

 than any other of the domestic animals. 



Cause. — The essential cause is the specific germ, the 

 tubercle bacillus, without which the disease could not exist. 

 Since the disease is found in the lungs in a large proportion 

 of cases, it is evident that tuberculosis is usually contracted 

 by inhaling the germs with the air. It may also be caused 

 by the ingestion of infected meat and milk and by direct 

 inoculation. 



The development of the disease is favored by anything 

 that tends to impair the general health of the animal, as 

 overcrowding in poorly ventilated stables, hereditary pre- 

 disposition, in-and-in breeding, lack of exercise, errors in 

 diet, etc. 



Symptoms. — The symptoms are very obscure, and in some 

 cases where the disease is well advanced there is seemingly 

 little alteration in the health of the animal. The most 

 prominent symptoms are a short, husky cough, enlargement 

 of the lymph glands around the throat, dulness, capricious 

 appetite, staring coat, and emaciation. 



Persistent oestrum or heat, with barrenness, especially 

 when there is a harsh, staring coat and general unthrifty 

 condition, is suspicious. 



The Tuberculin Test. — Tuberculin is a glycerin ex- 

 tract of the soluble products produced by the growth of the 

 tubercle bacillus, concentrated, filtered, and sterilized. 

 When properly prepared it contains no living germs and 

 cannot produce tuberculosis. It was introduced to the 

 medical profession by Dr. Koch as a cure for tuberculosis. 



