8, 



SYMPTOMS. 



It is suprising how few physical signs are present in Tuber- 

 culosis of cattle. This undoubtedly is due to the fact that the 

 animal has strong resisting powers, and does not give signs of 

 having the disease until the invasion of the system is complete. 



If the lungs are affected, then there will be a cough, rapid 

 breathing, pulse rapid, rise in temperature, nose dry, "off their 

 feed." Auscultation will generally reveal the condition of the 

 lungs. 



When the disease is located in the digestive or alimentary 

 tract, there is more or less disturbance of the digestion, and 

 generally there is a persistant diarrhoea. 



When the udder becomes the seat of the disease, there will 

 be found more or less inflammation, with hardness or tumor, 

 and often blood is found in the milk. This hardness may grow 

 until the quarter is useless and the entire gland becomes in- 

 volved in this manner and cannot secrete milk. 



How can we tell positively that the animal has Tubercul- 

 osis, or, in other words, diagnose the case? 



There are two methods that can be employed, namely ; by 

 the microscope and by the injection of tuberculine. 



By the use of the microscope in the examination of the cul- 

 tivations of the germs which have been cultivated upon steril- 

 ized mediums, which have been inoculated by specimens from 

 the suspected animal, if possible in collecting some of the dis- 

 charge coughed up from the lungs or air passages, or taken 

 from the food or from the dung, if the disease is situated in the 

 bowels, from the milk, if the udder be infected. 



These germs, if properly stained, will be shown under the 

 microscope. They are almost always found, if present, at an 

 early stage of the disease, in the dung, as cows generally swal- 

 low what they dislodge from the air passages and lungs, though 

 in some cases these germs have been found on the food by some 

 observers. 



THE TUBERCUWN TEST. 

 Tuberculin was discovered by Dr. Robert Koch of Berlin, 

 in 1890, and was first used experimentally in treating Tuber- 

 culosis in man. In these cases it was found that its injection 

 was followed by a rise of the body temperature, which led 



