CHEMISTRY OF THE PTOMAINES. 277 



Various observers have shown that peptone possesses a 

 toxic action, and some have been led to regard this toxicity 

 as not due to the peptone itself, but rather to the presence 

 of this or some other ptomaine. At least Briegee found 

 one specimen of dry Witte's peptone to be perfectly harm- 

 less ; whereas, the fresh peptone formed by fibrin digestion 

 possessed strong toxic powers. Moreover, this non- 

 poisonous peptone wheu exposed to the action of gastric 

 juice was found to yield tlie poisonous substance. The 

 poisonous nature of proteids and the physiological action 

 of this base will be described later. 



Pyocyanine, Ci^Hj^NOj, is the coloring matter of blue 

 pus, and is produced byihe action of bacillus pyocyaneus. 

 It was isolated by Ledderhose (1887) and is said to be an 

 anthracene derivative. On contact with the air it is oxidized 

 to pyoxanthose, a yellow substance. According to Kunz 

 it contains nitrogen and sulphur. The picrate is of a dark 

 reddish-brown color ; the platinum salt is black and some- 

 times is obtained as glittering fine golden needles. 



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