DESCRIPTIONS OF PATHOGENIC BACTERIA. l8l 



instance is on record where two typhoid fever 

 patients, who were infected with this organism 

 in the course of a musk injection, perished 

 from oedema. The bacteria of oedema are 

 frequently found in the earth and in marshy 

 soil. 



The disease of cattle known as " quarter- 

 evil/' " black-leg " or symptomatic anthrax, 

 the bacillus of which develops subcutantously 

 with production of gas, is caused by bacteria 

 which resemble those of malignant oedema in 

 almost all points. Infection of animals is 

 favored by the simultaneous introduction of lac- 

 tic acid, probably because this substance brings 

 about a necrosis of the cells. It is fora like rea- 

 son, probably,that according to Roger, the nat- 

 ural immunity of rabbits to this disease can be 

 overcome if the metabolic products of B. prodi- 

 giosus or of Staphylococcus be injected simultane- 

 ously with the bacillus of symptomatic anthrax. 

 Cattle, sheep, goats and guinea-pigs are espe- 

 cially susceptible, horses, asses and white rats 

 less so, while swine, dogs, rabbits, gray rats, 

 ducks, pigeons, and fowls appear to be immune. 

 Sometimes, for example in reciprocal protec- 

 tive inoculation, there appears to exist nothing 

 but a difference in virulence between the bac- 

 teria of malignant oedema and those of symp- 

 tomatic anthrax, but the question of actual 



