THE CLEAVAGE OF PROTEINS WITH ALKALI 99 



of Kiel, b. proteus, b. subtilis, b. megaterium, b. pyo- 

 cyaneus, b. pneumonise, and b. diphtheriae. Gelatin con- 

 tains no poison, but gelatin is an albuminoid and gives the 

 Millon test imperfectly, if at all. Nicolle and Abt 1 found 

 that Defresne's peptone does not yield a poison when 

 treated by our method, and we have confirmed this finding. 

 It would be interesting to know whether this peptone is 

 made from gelatin or from a true protein. The probabilities 

 are that in peptic digestion a point is reached when the 

 poisonous group in proteins is disrupted. In fact, as has 

 been stated (page 42), we have shown that the poison in 

 the cellular substance of the colon bacillus is slowly digested 

 and destroyed by digestion with pepsin-hydrochloric acid. 

 Therefore, it is not strange that certain peptones fail to 

 yield a poisonous body when disrupted with dilute alkali 

 in absolute alcohol. ' Witte's peptone, so-called, as is well 

 known, is not a peptone, but an albumose. 



This poison, like the whole protein of which it is a part, 

 is formed synthetically by the living cell. In case of the 

 colon poison we demonstrated this by growing the bacillus 

 in Fraenkel's modification of Uschinsky's medium, which 

 has the following composition: 



Water 10,000 parts 



Sodium chloride 50 parts 



Asparagin 34 parts 



Ammonium lactate 63 parts 



Di-sodium hydrogen phosphate 20 parts 



After a week's development the contents of these flasks 

 were poured into from two to three volumes of 95 per cent, 

 alcohol. The precipitate was filtered out and put into 

 absolute alcohol; next it was extracted in Soxhlets with 

 ether, dried, and powdered. This powdered cellular sub- 

 stance, when split up with 2 per cent, sodium hydroxide 

 in absolute alcohol, furnished the poison, the action of 

 which was demonstrated on guinea-pigs. Moreover, the 

 poison obtained in this way gave all the protein reactions 



1 Annales de 1'Institut Pasteur, February, 1908. 



