384 DISEASES OF SWINE 



not get sick. If this same animal were given this same dose of 

 virus without the serum he would die within ten days. Giving 

 the serum with the virus enables the animal to escape the disease. 



The virus germs that are introduced into the body in the giving 

 of this so-called double or serum-virus simultaneous method make 

 an attempt to cause an attack of cholera, but the germ-destroying 

 bodies in the serum are too active, and the hog-cholera virus is 

 destroyed before it is able to get in its work. 



While the battle is being fought between the virus and the 

 germ destroyers contained in the serum the cells of the body learn 

 their lesson, and they become educated in the matter of producing 

 these germ fighters. Just as a nation which begins a war with- 

 out a navy has to call on some other nation to loan them war 

 vessels. This nation learns the need of a good navy, and at once 

 sets about to build ships of its own. So the cells of the hog's 

 body, learning the need and usefulness of these germ-fighting 

 ships, begins to produce them on its own account, and once it has 

 developed the knowledge of how to produce these germ destroyers 

 it keeps a supply of them always on hand. 



The result of the knowledge gained is that the body of this 

 hog is always in a position to keep up a strong fight against hog- 

 cholera, and the germs of this disease will never again be able to 

 gain entrance and set up an attack. 



This is, in brief, just what takes place when we give the double 

 treatment. We not only protect the animal against the disease, 

 but we also send into the body teachers which show the cells of 

 the animal how to produce germ fighters of their own which will 

 enable them to always be prepared for another war against these 

 same germs. In other words, the immunity or protection gained 

 is permanent and lasts as long as the animal lives. 



Numerous experiments have been made by Drs. Dorset, 

 Niles, Fitzgerald, and many other investigators in this field, 

 which all go to show that the protection derived from the double 

 treatment is lifelong. This is a great advantage over the results 

 which follow the use of the single or serum-alone method of treat- 

 ment. We found that the protection given by this method was 

 only temporary in nature, and that it disappeared at the end of 

 thirty days, or six weeks at most. Here we have a method which 



