TUBERCULOSIS 



525 



TUBERCULOSIS 



This is a disease which has for years been on the increase 

 in both man and the lower animals. So widespread has the dis- 

 ease become that it is commonly referred to as the "great white 

 plague." The widespread distribution of this disease in our hogs 

 was never fully realized until the present thorough system of meat 

 inspection was put in force a few years ago. Over 25,000 head of 

 hogs are now condemned every year on account of this condition. 

 In addition to this, nearly 500,000 other carcasses are found 

 slightly affected, but not sufficiently so as to warrant condemning 

 the entire carcass. 



Fig. 79. — Hogs eating droppings from tuberculous dairy cattle; a common 

 cause of tuberculosis in hogs (B. A. I. Circular No. 201). 



Causes. — The active cause of tuberculosis is a specific germ, 

 known as the tubercle bacillus. This little germ is a very small, 

 microscopic body, which enters with the food and drink of the hog 

 or through the inspired air, and, locating in some favorable spot, 

 sets up a diseased condition, which may remain local at that point 

 or may spread throughout the entire body. 



This germ reaches the body of the hog almost always through 

 the food. The most common foods with which the germ enters 

 being feces from tuberculous cattle and milk from cows that are 

 suffering from the disease. In cattle with tuberculosis of the lungs, 

 when they cough and raise the tuberculous sputum from the lungs, 



