USE OF SERUM IN HOG-CHOLERA 367 



their advocates. As already mentioned in a previous section, 

 these are known as the single and double or simultaneous methods. 

 In the single method an injection is made with serum alone, 

 while in the simultaneous method a dose of virus blood sufficient 

 to produce death under usual conditions is given at the same time 

 as the serum. In this manner the hog receives an actual attack by 

 the virus of the disease, but is protected from ill effects by the 

 accompanying use of the serum. 



The single method will first be discussed, after which consider- 

 ation of the double method and its advantages will be given. In 

 the single method there is simply an injection of this protective 

 substance, known as "serum," into the body of the sick or exposed 

 animal, for the purpose of combating the disease if present or pre- 

 venting its occurrence if it has not yet made its start. 



The technic or method of administering serum is very simple, 

 and yet there are a number of very important points to be ob- 

 served if the best results are to be obtained. 



In the first place, it is necessary to get the animals into some 

 enclosed space where they can be caught conveniently and held 

 while the serum is being injected. The best time of day for doing 

 this work is early in the morning or late in the afternoon. In 

 the hot weather of summer if heavy hogs are handled in the heat 

 of the day they are hable to become overheated and die from heat 

 exhaustion. Many such deaths are blamed on the serum, when, in 

 reality, they are due simply to overheating by attempting to handle 

 the hogs in the heat of the day. 



With the hogs corralled in a suitable shed or small feeding pen, 

 the next step is to get the serum and instruments in readiness. 

 Some spot should be selected, if possible, where the work can be 

 done away from the sun. Get on the shaded side of the barn or 

 under a shade tree if possible. This protects the serum from ex- 

 posure to the rays of the sun, and is also conducive of comfort to 

 the operator and his assistants. 



The serum should be brought to the farm in the glass-corked, 

 paraffin-sealed bottles, and the seal should not be taken off the 

 bottle until ready to begin work. A table should first be improvised 

 by taking a clean box and turning it bottom side up, or the top 

 of a barrel may be used for this purpose. Over this should be laid 



