202 SWINE DISEASES 



The exact method of administering serum has been 

 freely discussed at various associations, and numerous 

 articles have appeared in various publications. The 

 operator must always provide clean and sterile instru- 

 ments. It is true that the instruments become con- 

 taminated as soon as used, but at least two needles should 

 be provided in order that one may be placed in a disin- 

 fecting solution while the other is in use. The syringe 

 should be sterilized by boiling after being used for a few 

 hours or after a herd has been immunized, before using 

 it on another herd. The serum and virus should be in- | 

 h'ected deeply into the muscle in order to insure rapid ' 

 'absorption. Bad results frequently are the result of 1 

 / failure of absorption of the serum or virus that has been / 

 I injected just beneath the skin in the subcutaneous fat. ' 

 ' Swine that' are in filthy, muddy pens should not be in- 

 jected because of the probability of infection in the needle 

 wounds, and swine that have quantities of mud or filth 

 upon their bodies should not be injected. All swine that 

 are injected should be reasonably clean, the point of 

 injection should be painted with tincture of iodine, and 

 the skin should be pinched after withdrawing the needle 

 to prevent leakage. 



The serum-alone method produces an immunity for a 

 period of from one week to three months, but it does not 

 entail any danger of infecting and producing cholera in 

 a cholera-free herd and establishing new centers of cholera 

 in a community free of the disease. By the proper use 

 of serum alone in communities where there are only a 

 few centers, cholera could be efficiently controlled. In 

 such cases the infected herd and all surrounding herds 

 should be immunized and if necessary the process could 

 be repeated six weeks later. This method of control is 

 not as applicable when several counties of a state, or the 

 entire state, is infected. Serum alone, when given in 

 large doses, is of considerable value in the incubation 

 period of the disease before the animals show visible 

 symptoms but after the temperature has risen. The 

 judicious use of serum in such cases has saved as high as 



