PREPARATION OF ANTI-HOG-CHOLERA SERUM 97 



it is of no particular consequence. Great prostra- 

 tion and severe dyspnea are the symptoms which 

 suggest impending death, especially when foam 

 colored with blood exudes from the mouth or nos- 

 trils. Hogs suffering thus should be kept cool, 

 their heads should be elevated, and they should 

 not be subjected to unnecessary handling. Some 

 will recover spontaneously. In fatal cases coma 

 and shallow breathing precede death. We have 

 tried hypodermic doses of strychnin under such 

 conditions, but while temporary relief is afforded 

 the treatment seems merely to delay death rather 

 than to prevent it. 



Fatalities sometimes occur when air is pumped 

 into the vein. These may be avoided by forcing 

 the outlet tube completely to the bottom of the 

 bottle, and by allowing, previous to each opera- 

 tion, a quantity of virus to pass through the out- 

 let sufficient to carry away bubbles that may be 

 accumulated in the rubber tube. Air in the vein 

 does not always cause death, but the risk is great, 

 and avoidable. 



Deaths from hog cholera as a result of hypering 

 are practically unknown, except in hogs that have 

 been purchased without a clear history of having 

 been properly immunized. 



During the interval between the date of hyper- 

 ing and that of the first bleeding for serum, about 

 ten days, careful observations of the hyper are 



