THE COW IN HEALTH AND DISEASE 93 



Nature of Tuberculosis. 



Tuberculosis is thought by many to be dis- 

 tinctly a condition affecting the lungs but 

 such is not the case. It may be found in any 

 part or any organ of the body. The condition 

 may be quite extensive or it may be so slight 

 as to be almost unnoticeable. 



It is frequently found in the membranes lin- 

 ing the abdominal cavity and the cavity sur- 

 rounding the lungs and when so it usually 

 has the appearance of very small rounded 

 nodules which may be very thickly studded 

 over the surface or may be very few in num- 

 bers. These small nodules have the appearance 

 of pearls hence this condition has often been 

 spoken of as "Pearly Disease." 



In other cows the lymph glands which are 

 situated throughout the body are affected and 

 the substance which they contain is cheesy like 

 in appearance and when cut into seems gritty. 

 The lymph glands are those little glands situ- 

 ated in the thin membranous curtain which 

 holds the intestines in position. They are also 

 found along the top-most portion of the lung 

 and many other parts of the body. They range 

 in size from a kernel of wheat to the size of a 

 small hickory nut. 



When the lungs are affected they become 

 heavy and solid and light in color and usually 

 contain large quantities of pus and also por- 

 tions of the lung will have become necrotic 



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