164 PHYSIOLOGICAL CHEMISTRY. 



EXPERIMENTS ON PUTREFACTION PRODUCTS. 



In many courses in physiological chemistry the instructors are so 

 limited for time that no extended study of the products of putre- 

 faction can very well be attempted. Under such conditions the 

 scheme here submitted may be used profitably in the way of a dem- 

 onstration. Where the number of students is not too great, a 

 single large putrefaction may be started, and, after the initial 

 distillation, both the resulting distillate and residue may be dis- 

 tributed to the members of the class for individual manipulation. 



Preparation of Putrefaction Mixture. Place a weighed mix- 

 ture of coagulated egg albumin and ground lean meat in a flask or 

 bottle and add approximately 2 liters of water for every kilogram 

 of protein used. Sterilize the vessel and contents, inoculate with 

 the colon bacillus and keep at 40 C. for two or three weeks. If 

 cultures of the colon bacillus are not available, add 60 c.c. of a cold 

 saturated solution of sodium carbonate for every liter of water pre- 

 viously added and inoculate with some putrescent material (pan- 

 creas or feces). 1 Mix the putrefaction mixture very thoroughly 

 by shaking and insert a cork furnished with a glass tube to which 

 is attached a wash bottle containing a 3 per cent solution of mer- 

 curic cyanide. 2 This device is for the purpose of collecting the 

 methyl mercaptan, a gas formed during the process of putrefac- 

 tion. It also serves to diminish the odor arising from the putre- 

 fying material. Place the putrefaction mixture at 40 C. for two 

 or three weeks and at the end of that time make a separation of 

 the products of putrefaction according to the following directions : 



Subject the mixture to distillation until the distillate and residue 

 are approximately equal in volume. 



1 Putrefying protein may be prepared by treating 10 grams of finely ground 

 lean meat with 100 c.c. of water and 2 c.c. of a saturated solution of sodium 

 carbonate and keeping the mixture at 40 C. for twenty-four hours. 



' Concentrated sulphuric acid containing a small amount of isatin may be 

 used as a substitute for mercuric cyanide. When this modification is employed 

 it is necessary to use calcium chloride tubes to exclude moisture from the 

 isatin solution. 



