BIOLOGY OF CLOSTRIDIUM WELCHII 389 



using phenolphthalein as indicator. The most abundant acids 

 are lactic, acetic and butyric. The acidity in all cases attains 

 its maximum between thirty-six and forty-eight hours incubation 

 at 37°, after which there is a slight drop to a value which remains 

 constant indefinitely, regardless of the longevity of the organism. 

 2. Action on proteins. Clostridium Welchii is characteristically 

 a fermentative organism and attacks proteins very slightly, and 

 then only in the absence of fermentable carbohydrates. If sugar 

 is present in a medium containing protein, the organism acts 

 upon it readily, leaving the protein unattacked. Egg-meat mix- 

 ture is not attacked appreciably, but produces a disagreeable 

 odor upon standing. The egg-meat mixture used is prepared 

 as follows : 



A. One-half pound of lean chopped beef is placed in 250 cc. 

 of water, neutralized with sodium carbonate and heated for 

 thirty minutes in the Arnold sterilizer with occasional stirrings. 

 This is then set away in a cold place for several hours after which 

 the fatty scum is removed. 



B. The whites of three eggs are placed in 250 cc. of water, 

 neutralized and heated with occasional stirring in the Arnold 

 sterilizer for thirty minutes to coagulate the albumen. 



A and B are mixed and 2.5 grams of 0.5 per cent calcium 

 carbonate (powdered) are added. The flask is plugged and 

 sterilized for thirty minutes at 112°. 



When this mixture is inoculated with Clostridium Welchii there 

 appears just the slightest fermentation due to the small amount 

 of sugar present in the meat and egg. 



Growth occurs in a 1 per cent casein solution, but the casein 

 is unattacked by the different strains isolated from milk and 

 feces. Peptone water alone and peptone in physiological salt 

 solution remain unattacked. In liver broth, the glycogen is 

 acted upon very readily with vigorous gas fermentation, whereas 

 the protein is slightly, if at all affected. On albuminous matter 

 alone, however, there appears some proteolytic activity which, 

 when a little sugar is present, is increased enormously. 



No evidence of fermentation occurred in cultures of Clostridium 

 Welchii grown in peptone water, egg-white and egg-yolk solutions, 



