342 PATHOGENIC BACTERIA. 



the culture-medium ; Chauveau used atmospheric pressure 

 to the extent of six to eight atmospheres and found the 

 virulence diminished ; Arloing found that direct sunlight 

 operated similarly ; Lubarsch found that the inoculation 

 of the bacilli into immune animals, such as the frog, and 

 their subsequent recovery from its blood, diminishes the 

 virulence markedly. 



Protection, can be afforded in still other ways. The 

 simultaneous inoculation of bacteria not at all related to 

 anthrax will sometimes recover the animal, as Hiippe 

 found. Hankin found in the cultures chemical sub- 

 stances, especially an albuminose, which exerted a pro- 

 tective influence. Chamberland has shown that pro- 

 tective inoculation by Pasteur's method has diminished 

 the death-rate from 10 per cent, for sheep and 5 per 

 cent, for cattle to about 0.94 per cent, for sheep and 0.34 

 per cent, for cattle, so that the utility of the method is 

 scarcely questionable. In 1890, Agata and Jasuhara 

 showed that in the convalescents from anthrax among 

 their experimental animals an antitoxic substance was 

 present in the blood in such quantities that i : 800 parts 

 per body-weight of dog's serum containing the antitoxin 

 would protect a mouse. Similar results have been at- 

 tained by Marchoux. 



Experiments of interest have been performed to show 

 that the natural immunity enjoyed by many animals can 

 be destroyed. Behring found that if the alkalinity of the 

 blood of rats was diminished, they could become affected 

 with anthrax, and numerous observers have shown that 

 when anthrax bacilli and unrelated organisms, such as 

 the erysipelas cocci, Bacillus prodigiosus, and Bacillus 

 pyocyaneus, are simultaneously introduced into immune 

 animals, the immunity is destroyed and the animals 

 succumb to the disease. Frogs have been made to suc- 

 cumb to the disease by exposure to a temperature of 37 

 C. after inoculation. Pasteur destroyed the immunity of 

 fowls by a cold bath after inoculation. 



In the natural order of events anthrax in cattle is 



