THE ANTHRAX PROTEIN 201 



kill a guinea-pig after intra-abdominal injection. Smaller 

 doses make the animals sick, but do not kill, and confer 

 no marked immunity to inoculation with living cultures. 



The cell substance has been split up by our method into 

 poisonous and non-poisonous portions. The former differs 

 in no recognizable way from the poisonous group obtained 

 from other proteins, and treatment of animals with the 

 latter fails to establish any noticeable immunity to inocula- 

 tion with the bacillus. 



It has been shown that the poisonous group in the cellular 

 protein of a non-pathogenic bacillus may be more effective 

 than that in the anthrax bacillus. The minimum lethal 

 dose of the air-dried cell of the prodigiosus for a guinea-pig 

 of from 200 to 300 grams body weight, when injected intra- 

 abdominally, is less than 3 mg., while that of the anthrax 

 bacillus for the same animal is about 200 mg. Even the 

 lemon sarcine, the least toxic of the non-pathogenic organ- 

 isms examined, surpasses the anthrax bacillus in toxic 

 action. These facts convince us that the pathogenicity of 

 a bacterium is not measured by its capability of furnishing 

 a poisonous group, but by its ability to grow and multiply 

 in the animal body. The high degree of infectivity shown 

 by the anthrax bacillus in some animals is due to the fact 

 that it grows without hindrance on the part of the secre- 

 tions of those animals. On the other hand, its failure to 

 infect other species is due to the inhibiting action of certain 

 secretions of these animals. 



Like other proteins, that of the anthrax bacillus contains 

 a poisonous group. The chief constituent of the anthrax 

 bacillus is a glyconucleoprotein, and by this we do not 

 mean a physical mixture of carbohydrate, nuclein, and 

 protein, but a molecule containing these constituents as 

 atomic groups. The intracellular poisons contained in 

 bacterial cells are not preformed toxins, as supposed by 

 Pfeiffer, but are atomic groups in a complex molecule. 

 The poison can be obtained from the protein only by 

 processes which disrupt the molecule. Mere solvents, 

 such as water, alcohol, ether, saline solution, and glycerin, 



