70 BACTERIOLOGY. 
C;5H,NO, + O, = CsHyNO; + H,0. 
Cholin, Betain. 
C,H,,NO, + O = C,Hy;NO, 
Cholin. Muscarin. 
The ptomain tyrotoxin, obtained from cheese by 
Vaughan, is apparently derived from butyric acid. 
Pyocyanin (C,,H,,N,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 rdle of 
self-poisons, or leucomains. Some believe the symp- 
toms designated as coma and tetany may be ascribed to 
the absorption of substances of this nature. Since the 
name ptomain 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 ptomains 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 ptomains 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 (HCl) are boiled down, 
filtered, and the filtrate concentrated to a syrupy con- 
