284 BLACK LEG 



fortifying 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 tlie 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 immunity which was reinforced after eight or 

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

 heated from go 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 onlv local swellings would occur. This process 

 is known as " the French method," Arloing" s or the " Lyons 

 method." 



In 1888, Kitt of the 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 tempera- 

 ture of from 85 to 90° C. for six hours. A single injection of 

 this vaccine would usually confer immunity. He further 

 modified Arloing's method by making the injections in the 

 shoulder regions 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 looking to the 

 preparation of a black quarter vaccine were begun in the 

 Bureau of Animal Industry at Washington by Dr. Norgaard 

 under the direction of Dr. Salmon. The various European 

 methods were tried. The one finally adopted consists of a 

 single vaccine, the Arloing principal 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 linen cloth. The juice is spread in layers on plates 



