PREPARATION OF ANTI-HOG-CHOLERA SERUM 115 



the serum contained in it is not required for im- 

 mediate use. 



The scope and purpose of this book do not allow 

 further detail which might profitably be included 

 in a more inclusive text. In leaving the subject 

 of serum production, let us emphasize again a 

 few essentials which make for clean, potent serum. 

 These include strong vigorous hypers that have 

 been immune to hog cholera a long time before 

 being hypered; a highly virulent strain of virus 

 that will " ripen'* pigs to kill in seven days, or 

 less; scrupulous cleanliness and strict antisepsis 

 in all operations; rapid cooling of all blood im- 

 mediately after it is drawn ; no unnecessary han- 

 dling or exposure of serum during the process of 

 defibrinating and straining; and finally, careful 

 observation of tests, with positive exclusion of 

 doubtful serum. 



Hog Cholera Virus 



Hog cholera virus, called by the trade "simul- 

 taneous virus " because it is used in the field in 

 conjunction with protective serum, is produced 

 by giving shoats doses of virus (usually 2 mils 

 each), allowing them to sicken, and drawing their 

 blood while the disease is at its height. This blood 

 is handled in exactly the same manner as hyper- 

 ing virus, differing from this latter product only 

 in that there is added to it as a preservative, 5 



