48 PROTEIN POISONS 



the cellular substance had been obtained, and 1 immunity 

 unit of antitoxin. These experiments show that while 

 diphtheria antitoxin protects against the extracellular 

 toxin it fails to protect against the intracellular poison. 



Suspensions of the diphtheria cellular substance when 

 exposed to a temperature of 50 or higher, for fifteen minutes 

 or longer, gradually decrease in toxicity, but this is not 

 wholly lost after exposure to 122 in the autoclave for 

 thirty minutes. The minimum lethal dose of our prepara- 

 tion having been found to be 1 to 33,000, it "was heated to 

 122 for 20 minutes, and then proved to be 1 to 6400. It 

 is worthy of note that the several strains of the diphtheria 

 bacillus employed yielded cellular substances that varied 

 widely in toxicity. As a rule, one that supplied a potent 

 extracellular poison yielded relatively an indifferent intra- 

 cellular poison. Possibly this is due to the greater lability 

 of the molecular structure of the former, which leads to 

 the partial breaking down of the protein molecule in the 

 heating resorted to in order to sterilize the growth. 



The cellular substance of the anthrax bacillus was pre- 

 pared and studied by J. Walter Vaughan. 1 This kills 

 guinea-pigs in only relatively large doses, and this fact 

 indicates that the intensity of the infectious properties 

 of a microorganism is not, always at least, measured by 

 the potency of its intracellular poison. The bacillus pro- 

 digiosus is non-pathogenic to the higher animals, not from 

 its inability to furnish a poison, but because it cannot 

 grow and multiply in the animal body; while, on the other 

 hand, the anthrax bacillus is highly infectious to some of 

 the higher animals, not from the intensity of the poison 

 which it elaborates, but rather from the fact that in these 

 animals this bacillus finds conditions favorable to its growth 

 and multiplication. 



Detweiler 2 prepared and demonstrated the poisonous 

 action of the cellular substances of b. prodigiosus, b. 

 violaceus, sarcina aurantiaca, and s. lutea. 



1 Trans. Assoc. Amer. Phys., 1902, xvii, 313. 



2 Ibid., 257. 



