268 SWINE 



point in the body, it develops into what is called a tuber- 

 cle. That is, the germ multiplies very rapidly, which 

 causes an irritation at the point and produces a swelling. 

 As this swelling continues to grow and the germs con- 

 tinue to multiply, it becomes hard, and still later the in- 

 terior of it will become mortified, decompose and form an 

 abscess. The contents of this abscess may be either in 

 the form of pus or may be dry and gritty. 



The tubercle bacilli gain entrance to the bodies of dif- 

 ferent species of animals in different ways. In the case 

 of man and also cattle the germ may be either inhaled or 

 taken in with the food. 



With swine the disease germs usually gain entrance by 

 being taken in with the feed, hence by ingestion. It is 

 only seldom that the disease starts in a hog by the germs 

 being inhaled. This being true, the disease is very easily 

 controlled with swine. The parts affected first in the hog 

 are usually the glands of the lymphatic system which are 

 located in the neck immediately back of the jaw bone. 

 Thus if the head of a hog is cut off at this point, it can 

 very easily be determined whether the hog has tuber- 

 culosis or not by first examining these glands in a healthy 

 hog, and then those of the hog killed. When these glands 

 are affected with the disease they take on the nature of a 

 tubercle ; that is, at first they may be simply enlarged and 

 congested, and later they may have small pus particles 

 scattered throughout which in the final stages may be- 

 come one large abscess. As these parts swell when the 

 tubercle develops they cause irritation in the throat and 

 may be responsible for the coughing that results from this 

 disease. When the lungs of a hog are affected, he will of 

 course always cough. As the disease develops the lym-" 

 phatic glands throughout the body are usually affected 



