Suppression and Prevention of Anthrax in Herds. 215 



others having a very little effect. The object in immunizing is to 

 stimulate to the increase of these defensive products in quantity 

 or power until an ordinary dose of the bacillus will fail to colo- 

 nize the tissues or the blood. In considering this subject a clear 

 distinction must be made between the simple bactericidal and the 

 antidotal or antitoxic products found in the serum of immune 

 animals and the toxins which are produced by the bacilli. The 

 soluble antitoxic and bactericidal agents found in the serum of 

 the immune, ma} 7 be employed for therapeutic purposes to pre- 

 serve life in an animal which has received a lethal dose of the 

 bacillus anthracis, but as these are rapidly eliminated from the 

 system, their protective power is very short lived, and if some 

 bacilli survive the period of their presence and potency, or if they 

 are introduced into the system later, the animal may fall a victim 

 to anthrax as if no such protective agent had been used. Behring 

 showed that the blood serum of the white rat proves fatal to the 

 bacillus anthracis, but Metschinkoff pointed out later that it must 

 be brought in contact with the bacillus in order to prove effective, 

 whereas if the serum and bacillus were injected at different parts of 

 the body no protection was obtained. The antidotal or bactericidal 

 action of the serum of an immunized animal acts at once, whereas 

 a permanent immunity cannot be established before about fifteen 

 days. The serum of the immune animal contains the following 

 elements antagonistic to anthrax : Antitoxi?i or leucomain which 

 may be poisonous to the bacilli, or chemical antidotes to their 

 products : globulicidal principles which distort or disintegrate the 

 blood globules and release their contents including the bactericidal 

 nuclein, and probably others. All such agents when injected 

 into the system are present only for a limited time and while 

 they may be made subservient to a temporary immunity, they can 

 give no permanent protection and must be considered mainly as 

 therapeutic agents. 



A permanent immunity must depend on a stimulation or educa- 

 tion of the system to the production of these protective agents 

 de novo or in increased quantity. This must be done by exposure 

 of the tissues to the toxins of the bacillus anthracis, and is ac- 

 complished slowly. Precisely what tissues are stimulated to the 

 production of the defensive agents is not fully known, though cer- 

 tain indications may be drawn from observant facts. The eosino- 



