MANUFACTURE OF HOG-CHOLERA SERUM 331 



the same species that does not possess an immunity to the disease 

 against which they are protective agents. 



(5) On the other hand, these antibodies, when injected into the 

 body of an exposed animal, act as protecting agents, and prevent 

 an attack of the disease in the animal into which they have been 

 injected. 



(6) In an immune animal future attacks by the germs of this 

 particular disease produce no symptoms. They do, however, 

 stimulate the further production of germ fighters or antibodies. 



(7) If enormous doses of the disease virus are introduced, marked 

 stimulation of the cells takes place, and there is an enormous in- 

 crease in the number of antibodies to be found in the blood-stream. 



(8) Injection of large amounts of virus for purpose of stimulating 

 antibody formation is known as hyperimmunization. The ani- 

 mal so treated is classed as hyperimmune. 



(9) The blood from one of these hyperimmune animals possesses 

 unusual protective power when injected into the body of another 

 susceptible animal which may have been exposed to the same 

 disease. 



(10) By use of a hyperimmune blood we are able to give much 

 smaller doses and get the same amount of protection as from enor- 

 mous doses of blood from an animal that has only a simple im- 

 munity. This materially lowers the cost of production of the serum 

 and the expense of treatment. 



MANUFACTURE OF HOG-CHOLERA SERUM 



For a number of years hog-cholera serum has only been manu- 

 factured by the United States Government, the various state ex- 

 periment stations, numerous large pharmaceutic houses, and sev- 

 eral private or commercial firms that sprung up here and there 

 over the country. In the past year the demand for serum has 

 become so much greater than the available supply that a number 

 of prominent veterinarians over the country have completed ar- 

 rangements to enter into the manufacture of serum on a small 

 scale for their own private use. 



The manufacture of this product is very simple, but, at the 

 same time, requires a very thorough knowledge of the elementary 

 principles underlying its production, and, above all, a most careful 



