Biological Therapy 



157 



used in the proper manner, active immunity is certain to 

 result from its use for simultaneous treatment. 



In addition to the above tests we conduct on every lot 

 of virus the same tests for purity which are described under 

 the production of anti-hog-cholera serum. 



Each serial lot of virus is given a dating of sixty days 

 from the time it is produced. Although virus retains its 

 virulency beyond this date the use of expired virus is not 

 advised whenever unexpired virus is available. 



PRODUCTION OF ANTI-HOG-CHOLERA SERUM 



This is sometimes referred to as a crude biological pro- 

 duct due to the fact that the red blood corpuscles remain in 

 the finished product. The presence of these corpuscles does 

 prevent the product from having the finished appearance 

 possessed by other immune sera. The presence of corpuscles 

 is in no way harmful, in fact recent researches indicate the 

 great value of the transfusion of red blood corpuscles, which 

 are decidedly beneficial to the recipient. In addition to 

 this we must realize that no biological product known has 

 given more uniformly satisfactory and dependable results 

 than high-quality whole blood anti-hog-cholera serum. 

 Neither has any other biological product accomplished a 

 greater saving by the prevention of disease. 



In the production of anti-hog-cholera serum, swine 

 which have been immunized by the simultaneous treatment 

 at least sixty days previously, are subjected to the process 

 of hyperimmunization. This is accomplished by injecting 

 intravenously through the marginal ear vein a quantity of 

 virus which represents five c.c. for every pound which the 

 animal weighs. Healthy animals, if properly immunized, 

 manifest little or no reaction to this process, whereas swine 

 not properly immunized develop acute hog cholera. 



The hyperimmunizing process is followed by an inter- 

 val of ten days during which time the cells of the body, again 

 stimulated by this enormous dose of antigen, are actively 

 engaged in the production of antibodies. These antibodies 

 formed by the cells are liberated and are present in enor- 

 mous quantities in the blood of the animal within ten days 

 days after hyperimmunization. After this interval the ani- 

 mal may have a portion of its blood extracted from the tail 

 by a special vacuum apparatus or may be bled to death. 



