PRACTICAL APPLICATIONS 405 



recommended by Calmette, by Besredka, and by Shiga ; the last- 

 named obtained very good results by its use in an epidemic in 

 Kobe. 



Anthrax. 



The nature of the toxin of anthrax is quite unknown, although 

 it has been the subject of much experimental investigation. No 

 exotoxin is formed in ordinary media. If coagulable or coagulated 

 proteids are present in the medium, they will be broken down into 

 peptones, etc., which have some toxic action, but no true toxin is 

 produced. Some observers have found that the filtrate from broth 

 cultures of anthrax, though devoid of toxicity, may have some 

 immunizing powers, a result which we should now attribute to 

 the presence of free receptors. The only importance attaching to 

 these facts is that they may explain the results obtained by some 

 investigators, who obtained albumoses and other bodies of very 

 feeble toxicity from various culture media, and considered them 

 to be the true toxin because they served to immunize animals. 

 And, according to Conradi, there is no evidence in favour of the 

 existence of an endotoxin. Bacilli killed by various methods and 

 disintegrated by Buchner's process yielded a non-toxic fluid. 

 The clinical nature of the disease in some of its manifestations 

 (especially pulmonary anthrax) would rather lead us to believe 

 that a powerful toxin is produced, but of this there is not the 

 slightest shred of experimental verification. 



The process of recovery and the subsequent immunity are also 

 very difficult to understand. Local immunity is very marked, 

 the skin being highly resistant in comparison with the lungs, an 

 infection of which region forms one of the most rapid and intract- 

 able diseases known in man. There are very marked differences 

 with regard to the immunity of different animals. The fowl is 

 highly immune, as are cold-blooded animals. The rat and dog 

 are partially immune, whereas sheep, cattle, and the small animals 

 of the laboratory are very susceptible. 



It is especially noteworthy in the case of anthrax that the 

 presence of bactericidal substances in the blood is no indication 

 whatever as to the degree of immunity* The serum of the rabbit, 

 a highly susceptible animal, has an extremely powerful bactericidal 

 effect, whereas that of the dog and rat have but little. The 

 classical Pfeiffer's phenomenon is not seen in the case of this 

 bacillus, but the altered bacteria may be readily recognized from 



