SUGAR IK THE NUTRIENT MEDIUM. 133 



So far as they have been closely examined, the 

 majority belong to the following groups : 



1. Amins. Methylamin, dimethylamiu, and tri- 



/CH 3 /CH 3 



N-H N CH 3 



\H \H 



methylamin, similar to ethylamin, diethylamin, and 



/CH 3 



N-CH 3 



\CH S 



r /NH 2 

 \ IT 



triethylamin. Ethylendiamin || /H and its homo- 



logues, dimethylethylendiamin-putrescin, with which 



sepsin is isomeric; pentamethylendiamin is called 



cadaverin. The most virulent one is ethylendiamin. 



2. Ammonium Bases. The best known is cholin- 



/CH 3 



/>CH 3 

 bilineurin = N- CH 3 



Muscarin (C 6 H 15 NO 3 ) is closely allied, and likewise 

 vinylcholin (C 5 H 13 NO) and neuridin (C 5 H 14 N 2 ). 



3. Pyridin derivatives. Derived from pyridin 

 C 6 H 5 N; the principal ones that have been found are 

 collidin C 8 H U N and parvolin C 9 H 13 N. 



4. Indol (C 8 H 7 N) and skatol (C 9 H U N), vide page 142. 

 In addition, amido acids (leucin, tyrosin, etc.), sub- 



stances allied to guanidin (C(NH)(NH 2 ) 2 ) and numer- 

 ous other imperfectly characterized bodies have been 

 discovered. It would be useless to mention them 

 here as the poisonous ones are no longer regarded as 

 the true viruses of the disease (vide page 135). 



