42 PROTEIN POISONS 



One hundred milligrams of the cellular substance was 

 boiled in an open test-tube with 10 c.c. of a 0.2 per cent, 

 dilution of hydrochloric acid. This induced no visible 

 alteration in the bacterial cells, as seen under the micro- 

 scope, and the injection of this material into animals caused 

 death in the usual time and with the usual findings. 



6. Heating the cellular substance for an hour in an 

 open dish on the water-bath (about 80) , with from 1 to 5 

 per cent, solutions of hydrochloric acid, breaks up the cells 

 but does not wholly destroy the toxicity of the cell content; 

 however, prolonged boiling with 1 per cent, or stronger 

 dilutions of hydrochloric acid does destroy the poison. 



Five hundred milligrams of the colon cellular substance 

 was heated on the water-bath for one hour with 500 c.c. 

 of a 5 per cent, solution of hydrochloric acid and then 

 decanted through a hard filter. The filtrate was clear 

 and colorless and gave no appreciable precipitate when 

 dropped into absolute alcohol, but that the acid had dis- 

 solved some part of the cellular substance was shown by 

 the response of the filtrate to the biuret test. 



The undissolved material was suspended in a dilute 

 solution of sodium bicarbonate, sufficient to neutralize the 

 acid, and injected into guinea-pigs which died in the charac- 

 teristic way, and showed the usual lesions. 



7. The bacterial cellular proteins are, so far as their 

 toxicity is concerned, quite resistant to the action of pepsin 

 and trypsin. 



A given sample of the cellular substance of the colon 

 bacillus was tested upon a large number of guinea-pigs, in 

 order to determine the minimum lethal dose, which was 

 found to be for half-grown animals 0.5 mg. given intra- 

 abdominally, and 1 mg. subcutaneously. This material 

 was then subjected for three days to an artificial gastric 

 juice, the efficiency of which was demonstrated simul- 

 taneously by its action on coagulated egg-white. The 

 soluble and insoluble parts were separated and their toxicity 

 tested. One-half milligram of the undigested part given 

 intra-abdominally did not kill but 1 mg. did; while 1 mg. 



