656 Symptomatic Anthrax 



When the guinea-pig is inoculated with the bacillus of 

 symptomatic anthrax, it dies in from twenty-four to thirty- 

 six hours. The post-mortem examination shows bloody 

 serum at the point of inoculation, and dark red or black 

 muscular tissue like that of the "black-leg" of cattle. No 

 changes are apparent in the internal organs. The bacilli 

 are at first found near the point of inoculation in the inflam- 

 matory exudations only, but soon after death, being motile, 

 they spread to all parts of the body. 



Virulence. The virulence of the organism is soon lost in 

 all culture media, but it is said that lost virulence can be 

 brought back and existing virulence much increased by the 

 addition of 20 per cent, of lactic acid to the culture. 



Vaccination. The virulence of the bacillus can easily be 

 attenuated by exposure to heat, by exposure of its spores 

 to heat, or by drying combined with exposure to heat. In- 

 oculation of animals with attenuated bacilli causes a mild 

 local affection, followed by complete immunity against the 

 virulent organisms. Upon this principle the prophylactic 

 vaccination is based. Kitt* has shown that dried muscle 

 from an infected animal is more efficacious for the purpose 

 of immunizing than cultures of the bacilli. 



The method of preparing the so-called "vaccines" is very simple. 

 A calf is inoculated in the muscular tissue with a virulent culture. As 

 soon as it dies, the black, spongy muscular tissue is dissected out, cut 

 into small pieces, and dried in an oven at about the body temperature. 

 When dry, the muscle is ground to a coarse powder, then heated for 

 the purpose of attenuating the virulence of the contained bacilli. Two 

 inoculations, one of pulverized muscle heated for six or seven hours 

 to 100-104 C., and a week later one heated to 85-90 C., were 

 originally used, but most observers are now agreed that a single in- 

 jection of muscle attenuated by six or seven hours' exposure to 85 C. 

 will suffice for immunization. The muscle-powder is simply crushed 

 in a mortar, in a convenient quantity of sterile water, and injected 

 hypodermically. 



The statistics of Guillod and Simon, based upon 3500 protective 

 inoculations, show a death-rate from 5-20 per cent, in unprotected 

 animals and 0.5-2 per cent, in protected animals. 



Immunity against symptomatic anthrax seems, however, 

 to be one of degree, for Arloing, Cornevin, and Thomas found 

 that when the bacillus is introduced simultaneously with a 

 20 per cent, solution of lactic acid, either the virulence of 



* "Centralbl. f. Bakt., Parasitenk., u. d. Infektionskrankh.," Bd. in, 

 Nos. 18 and 19. 



