FAKMEK's' INSrn I'TKS. Si'J 



tired Ml- nunc tiiiU's yroatcr lliiiii witiild liiivc htcii lolcialcil :it tlic lirsl 

 iiiociilatidii. Till' lilood of sudi an animal will possess enormous im- 

 munizinj; power. \\'hen iised iipou the piitieiit, however, it simply adds 

 iliai property to the blood and does not cause its developmentin the hody. 

 The immunity eonferred, lasts for oidy a short time, from four to eii^ht 

 weeks, oi- long eiioush to pass over a'i>eriod of infection. A similar line 

 of work has been done in connection witli Ikjj^ cholera and swine plaurue. 

 The results have been interesting from a scientific standpoint rather than 

 the practical. The cost in developing the serum, the care needed in its 

 application and the short p«'riod of immunity eonferred have all been 

 against it. It Avas used in the government experiments, l)Ut only a few. 

 tirnis ventured into the production upon a commercial scab' and none are 

 in ojieration as far as Ivuown to the writer. 



Toxin Method.— In this method the germs of the disease are grown in 

 a suitable media like beef bouillon and when they liave produced about 

 all tlie poison they will, they are then filtered off and the poison is injected, 

 tirst in a small and then in a large dose thus stimulating the l)ody to pro- 

 diice its own antitoxin. This is the method used in developing a 

 strong antitoxin in the horse's blood against dii)htlieria but it is not prac- 

 tical in its aijjriieation to the treatment of millions of liogs on the farm. 



