INFECTIOUS DISEASES 



299 



The exact method of administering serum has been freely discussed 

 at various associations, and numerous articles have appeared in vari- 

 ous publications. The operator must always provide clean and sterile 

 instruments. It is true that the instruments become contaminated as 

 soon as used, but at least two needles should be provided in order that 

 one may be placed in a disinfecting 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 injected deeply into 

 the muscle or preferably into the axillary space, in order to insure 



Fig. 83. STEEiLiziNG KOOM. 1, electilc sterilizer; 2, autoclave; 

 utensil used for collecting blood. 



3, type of 



rapid absorption. Bad results are frequently due to failure of absorp- 

 tion of the serum or virus that has been injected just beneath the skin 

 in the subcutaneous fat. Swine that are in filthy, muddy pens should 

 not be injected, 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 iodin, 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 



