Hog Cholera and Its Prbvextion. 137 



tical experiment to determine its potency before being sent 

 out and is then ready for use. If properly prepared, the 

 serum is undoubtedly effective in immunizing against chol- 

 era when used in doses of twenty to twenty-five CO for hogs 

 weighing one hundred pounds, with doses of fifteen CC 

 extra for each successive one hundred pounds of live weight 

 of hog. 



In warding off or preventing cholera by use of serum one 

 of two methods may be employed. First, by the injection 

 of serum alone under the skin or into the muscles of the 

 animal. This is known as the simple serum method and 

 gives only temporary immunity, say for about thirty days. 

 The second method, known as the simultaneous method, 

 consists in the injection of the same amount of serum, but 

 at the same time a small amount of cholera virus, from one 

 lo two CC, according to the age and size of the animal, is 

 also injected into the animal being treated. The second 

 method produces what is known as active immunity, and 

 is permanent in its charstcter, lasting during the period of 

 the animal's life. 



Which ever method is employed certain essentials must 

 be absolutely insistjed upon if any degree of success is to 

 follow the work; and particularly in the simultaneous 

 method must this be so if disastrous results are to be 

 avoided. 



These essentials are: First, the serum and virus used 

 must he pure and potent; and second, the person treating 

 the hogs must know his business thoroughly — that is, he 

 tnust he able to know hog cholera when he sees it, he must 

 know which method to employ under the given or existing 

 conditions, and he must understand how to do the work. 

 Failure in the observation of these requirements will ex- 

 plain why there are still so many breeders and farmers 

 who doubt or question the efficacy of the serum treatment 

 and hesitate in its use. 



To secure the proper kind of serum and virus it is nec- 

 essary that all serum and virus should be tested to deter- 

 mine their potency before they are sent out for use, and 

 this by expert supervision, under state or federal control. 

 Ample means and equipment for their manufacture should 

 be provided so that when emergencies arise and the de- 



