70 BACTERIOLOGY. 



C 5 H 15 N0 2 + 2 C 5 H 13 N0 3 + H 2 0. 



Cholin, Betain. 



C 5 H 15 N0 2 + O C 5 H 13 N0 3 



Cholin. Muscarin. 



The ptomai'n tyrotoxiu, obtained from cheese by 

 Vaughan, is apparently derived from butyric acid. 



Pyocyanin (C 14 H 14 N 2 O), which produces the color of 

 blue or blue-green pus, and has been regarded by Led- 

 derhose as related to the coal-tar products, is a ptomainic 

 pigment. Similar bodies of a basic nature may be found 

 in the intestinal contents as the products of bacterial 

 decomposition. Some of these are poisons and can be 

 absorbed into the body, where they play the role of 

 self-poisons, or leucomai'ns. Some believe the symp- 

 toms designated as coma and tetany may be ascribed to 

 the absorption of substances of this nature. Since the 

 name ptomai'n was given to the poisonous products of 

 bacterial growth before these products were chemically 

 understood, and even now, when the name is restricted 

 to crystalline bodies, it is by many frequently applied 

 to all bacterial poisons, as in cases of poisoning due to 

 decomposing meat or sausage or to cheese or milk. 

 Instead of ptomai'ns these may be due to the poisonous 

 proteids or toxins. Such poisonous proteid bodies are 

 always formed in the beginning of decomposition pro- 

 cesses. Some of the ptomai'ns obtained by chemists 

 are due not to putrefactive changes but to the chemi- 

 cal methods used to obtain them. 



The isolation of these substances can here be only 

 briefly referred to. According to Brieger's method, 

 which is the one now generally employed, the cultures 

 having a slight acid reaction (HC1) are boiled down, 

 filtered, and the filtrate concentrated to a syrupy con- 



