414 



AGRICULTURE 



contracting cholera has, however, been discovered. This 

 is to give well hogs anti-cholera serum ; or, in effect, 

 vaccinate them, as is done with people for smallpox and 

 diphtheria. 



The hog cholera serum is secured by drawing blood from 

 a hog which has first been rendered immune to cholera, 

 either by having had the disease or being given a special 

 treatment for the purpose of immunizing, and then having 

 had cholera germs injected into his veins. Each animal of 



I had serum. 



I wish I had. 



the herd to be treated is given by hypodermic injection a 

 certain quantity of this serum in proportion to its size. 



If the treatment is successful, it will immunize the herd 

 against cholera for several weeks. When the serum is 

 given to well herds, a cholera hog is sometimes brought 

 among them, or its carcass even fed them, at the time the 

 treatment is given. This method is thought to make the 

 immunity more certain. 



Success of the serum treatment. The success of the 

 serum treatment is still questioned by many. It seems rea- 



