202 SYMPTOMATIC ANTHRAX 



§ 159. Preventive inoculation. Several methods of 

 fortif^-ing exposed animals against the infection of sympto- 

 matic anthrax virus have been proposed. In 1880, Arloing, 

 Cornevin and Thomas demonstrated at Chaumont that animals 

 injected with the filtrate of cultures of this virus into the jugu- 

 lar vein were protected against inoculation with the strong 

 virus. It was found, however, that this method was difficult 

 as the vein had to be exposed and the greatest care was neces- 

 sary to prevent infection of extra vascular tissue in introduc- 

 ing and withdrawing the syringe. Later these investigators 

 attenuated the virus by heating it to a temperature of 100 to 

 104° C. and injecting it into the subcutis of the shoulder. This 

 gave a partial immunit}' which was reinforced after eight or 

 ten days by a second inoculation of a virus that had been 

 heated from 90 to 94° C. for six hours. They injected the 

 virus where the subcutis is quite dense, such as at the end of 

 the tail where only local swellings would occur. This process 

 is known as "the French method " Arloing's method or the 

 " Lyons method. ' ' 



In 1888, Kitt, of tlie Veterinary College in Munich, after 

 a careful investigation of the subject proposed a single injec- 

 tion method using a virus attenuated by heating at a 

 temperature of from 85 to go° C. for six hours. A single in- 

 jection of this vaccine would usually confer immunity. He 

 further modified Arloing's method by making the injections in 

 the shoulder region where the skin is looser and the operation 

 easier. Later, Kitt made further important investigations 

 concerning preventive vaccines for this disease. 



In the fall of 1896, investigations preparatory to the prepa- 

 ration of a black quarter vaccine were begun in the Bureau of 

 Animal Industry at Washington by Dr. Norgaard under the 

 direction of Dr. D. E. Salmon. The various European 

 methods were tried. The one finally adopted consists of a 

 single vaccine, the Arloing principle, with Kitt's modification. 



The material used for the vaccine is obtained from a fresh, 

 blackleg tumor, by pounding the muscle tissue in a mortar 

 with the addition of a little water and .squeezing the pulp 

 through a piece of linen cloth. The juice is spread in layers 



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