498 ANAEROBIC BACTERIA 



Toxin. According to Leclainche and Vallee, 1 and Grassberger and 

 Schattenfroh, 2 the filtrates of broth cultures of the bacillus are slightly 

 toxic to guinea-pigs in large doses. 



Pathogenesis. The organism is not, so far as is known, pathogenic 

 for man. At the site of inoculation in animals there is a rapidly 

 spreading edema which appears to be very painful. Usually the 

 most prominent naturally occurring lesion is a swelling of the front 

 or hind quarters; the lesion practically never extends below the knee. 

 The edematous area is almost black, due apparently, in part at least, 

 to changed blood pigment, and the area is surrounded by a zone of 

 hyperemia. The hair over the edematous area falls out easily. There 

 is considerable degeneration of the muscular tissue in the edematous 

 zone, and there is in it a sanguineous exudate which contains relatively 

 few leukocytes. The edematous area is crepitant, due to accumulated 

 gas bubbles, and there is a rather strong odor of butyric acid. The 

 incubation period is from one to three days. 



Sporulation does not take place in the tissues of the living animal, 

 but it is said to take place in from twenty-four to forty-eight hours 

 after death. If the spores are washed free from toxin and other bac- 

 teria they are said not to be infective for experimental animals, 

 according to Leclainche and Vallee. 3 



Vaccine. One attack of symptomatic anthrax appears to confer 

 immunity to subsequent attacks. Young cattle are usually infected; 

 older ones appear to be more resistant to infection. A vaccine has 

 been prepared which protects the animal from infection. The general 

 process of manufacture is to remove the infected tissues of animals 

 dead of symptomatic anthrax and dry them under aseptic conditions 

 at 37 C. 4 From this dried tissue two vaccines are made up, the first 

 being prepared by mixing the dried powder with sterile water 5 to form 

 a paste, which is heated to 100 C. for six hours. This is the first 

 vaccine, which will not kill experimental animals. It is injected at 

 the tip of the tail. In seven days a second vaccine (prepared from 

 the same powder and heated to 94 C. for four hours) is injected in 

 the same manner. This vaccine will ordinarily kill small experimental 

 animals. These two vaccines or modifications of them are widely 

 used for protecting cattle against blackleg. 



1 Ann. Inst. Past., 1900, 202. 



2 liber das Rauschbrandgift, 1904. 3 Loc. cit. 



4 This temperature does not diminish the virulence of the bacteria ; the potency of 

 the dried virus remains unimpaired for eighteen to twenty-four months. 

 6 Two parts sterile water to one part of dried powder. 



