300 BUILDINGS, SANITATION, AND DISEASES 



(1) "The first method is to use the serum alone. In this 

 method there is simply injected into the tissues of the hog a 

 dose of the anti-hog-cholera serum, which makes the hog 

 immune against cholera for a time varying from a few weeks 

 to several months." 



(2) " In this method there is injected at the same time with 

 the serum, but in a different place, a small amount of virulent 

 blood, or blood taken from a hog very sick with cholera/' This 

 method is known as the simultaneous method, and renders a hog 

 immune for life. It is counted a satisfactory method to use in 

 a herd before it has become infected, but great care must be 

 exercised not to use too much of the virulent blood, lest the 

 hog be given a severe form of the disease. 



(3) " This method is known as the combination method. 

 The hog is first vaccinated with the serum alone, and ten days 

 later vaccinated with the simultaneous method." This method 

 was originated by the author of the bulletin, Dr. Schoenleber, 

 and is claimed by him to be the safest and most satisfactory 

 method to employ in an exposed herd. 



The bulletin referred to above gives full directions for 

 vaccinating and handling the herd, but recommends that none 

 but skilled veterinarians perform the operation. 



From very extensive tests, Dr. Schoenleber draws the fol- 

 lowing conclusions : " Vaccination should be done while the 

 animals are still healthy, but if cholera is present, a large 

 per cent is saved through the use of the serum, and the earlier' 

 it is used in an outbreak the greater the per cent saved." 



SWINE PLAGUE. 



Swine plague is sometimes mistaken for hog cholera, and 

 often accompanies the latter disease. It is an infectious disease 

 caused by a germ, and the symptoms are similar to those of 



