148 ANTHRAX 



Station, has shown the possible efficiency of this method. Of 

 the 331 cows which they vaccinated against anthrax, two died 

 of the disease, giving a death rate of less than i per cent and 

 this in a territory so saturated with the virus that it was prac- 

 tically impossible to keep cattle at all before its use. 



A more critical study of the reports on the use of this 

 vaccine shows that while success can not be denied, failures 

 must be admitted. It is reported both in England and Ger- 

 many that the Pasteur vaccine has not been a marked success. 

 In England, Klein, who tested the vaccine used in that coun- 

 try, found that if the animals did not die from the effect of the 

 vaccine, they did when exposed to the disease. The German 

 veterinarians and agriculturalists agree that the first vaccine 

 is mild and harmless, but that the second vaccine, even in the 

 hands of experts, is dangerous and often fatal. In the state 

 of Illinois a number of cattle died of anthrax immediately 

 after receiving the second vaccine, and in Manitoba a large 

 number (about 500) of sheep died after the second vaccination 

 (Higgins). In these cases the vaccine u.sed was not suffi- 

 ciently attenuated. In a recent outbreak in the state of New 

 York the animals that were vaccinated, but not carefully 

 isolated from the infected pastures, continued to die of the 

 disease after the second vaccination. This was due to the 

 excessive attenuation of the vaccine. In the summer of 1907 

 a large number of cattle in an infected territory were vaccin- 

 ated with very good results. On a few farms, all of the unvac- 

 cinated cattle died of anthrax, while the vaccinated ones 

 remained well. It is reported to have been demonstrated by 

 experiment that the virulence of the attenuated virus can be 

 easily restored. Again, it has been shown by the investiga- 

 tions of Chester and Neal, of the Delaware College Agri- 

 cultural Experiment Station, that a vaccine which succeeded 

 at one time subsequently proved fatal. The vital objection to 

 this method is, that it requires the use of the living bacteria, 

 which later may become virulent and consequently cause a 

 subsequent outbreak. The scattering of pathogenic organisms, 

 even in an attenuated condition, should be avoided if possible. 



