MANUFACTURE OF HOG-CHOLERA SERUM 349 



between the thumb and forefinger of the right hand, and, by a 

 quick movement, sharply plunged through the skin and under- 

 lying tissues into the lumen of the vein. It can be easily told when 

 the needle is in the vein, as blood will flow out through the opening 

 in the needle. The hose is now quickly attached, and the pressure 

 of the air in the bottle raised by gently compressing the rubber 

 bulb a few times. By repeating this pressure at regular intervals 

 a constant flow of blood can be kept up through the needle and 

 into the vein. This flow should be continuous, but not too rapid, 

 the usual time taken to inject a 200-pound hog being about twenty 

 minutes to a half-hour. 



When the desired amount of virus has been injected the needle 

 is removed, and the opening in the skin of the ear washed off with 

 alcohol or touched with tincture of iodin. It is a good plan to also 

 apply a small amount of styptic collodion or tar to keep flies from 

 collecting upon the puncture wound and forming a sore. The 

 animal is then loosened and turned out of the crate into a lot. 



Before finally releasing the animal a tag bearing an identifica- 

 tion number should be attached to the opposite ear by means of 

 a hog ring. This number should be copied on the record card of 

 the animal and serves as a means of future identification. 



, This record card should show the number of the animal, color, 

 sex, weight, date of injection, temperature, and amount of virus 

 given. One week later this card is sent to the bleeding room with 

 the hog, and serves as a comparative record for determining the 

 condition of the animal as a result of the injection of the virus. 



For the first twelve hours after hyperimmunization the ani- 

 mals should be given but little feed, and should preferably be kept 

 in a shaded feed lot, with plenty of water to drink. In hot weather 

 they may show some signs of heat exhaustion or collapse as a re- 

 sult of the exertion, and also partly as an effect of the introduction 

 of such a large amount of foreign material into the body. In these 

 cases many lives can be saved by promptly injecting i to ^ gr. 

 of strychnin in 1 ounce of whisky or aromatic spirits of ammonia. 

 At the first signs of collapse the virus injection should, of course, 

 be stopped and the animal released. Cold water may be applied 

 over the head, but should not be applied over the balance of the 

 body. 



