294 INFECTIONS OF THE DIGESTIVE TRACT 



form of putrefaction is pronounced is often intense and 

 characteristic, suggesting butyric or caproic acid. When 

 proteids are attacked by B. aerogenes capsulatus there is 

 not only a production of butyric acid, but also a libera- 

 tion of gas, although there is less gas liberated than when 

 the organisms attack carbohydrates. The gas liberated 

 consists in part of hydrogen and in part of carbon 

 dioxide. Perhaps some methane is also formed. As a 

 result of the excessive production of gas the faeces have 

 a low specific gravity and float on the surface of water. 

 Frequently small bubbles of gas may be seen to be 

 liberated. The presence of considerable quantities of 

 gas in the form of small bubbles in the intestinal contents 

 contributes to give them a light color. Another factor 

 which enters into the light color often observed in the 

 faeces in cases of saccharo-butyric putrefaction is a re- 

 duction of bilirubin and other coloring matters by the 

 anaerobic bacteria. Reducing processes normally go 

 on in the intestinal tract but they are usually of moder- 

 ate intensity in conditions of health. In excessive sac- 

 charo-butyric putrefaction, on the contrary, the processes 

 of reduction are extremely active, owing doubtless largely 

 to the liberation of free hydrogen. The faeces of cases 

 of saccharo-butyric putrefaction when subjected to an 

 appropriate oxidizing agent, such as mercuric chloride 

 in concentrated solution, usually give a strong pink or 

 red color which is rendered more striking when the 

 material which has already been reddened in this way is 

 thrown into water, which then dissolves out the newly 

 formed coloring matter and reveals its intensity. This 



