390 J. RUSSELL ESTY 



a 1 per cent casein solution, and egg-meat mixture incubated 

 for one week at 37.5. In the case of peptone egg-white 100 per 

 cent of gas forms after a week's incubation. After two weeks' 

 growth spores are observed in all the media except casein. 



While there appeared to be a slight decrease in the bulk of 

 the proteins in some instances, as well as disagreeable odors, the 

 transformation never assumed the character of real putrefaction. 

 The unpleasant odor is presumably due to the presence of butyric 

 and closely allied acids and not to any product of decomposition 

 of proteins. 



By putrefaction is meant the ability to decompose native 

 proteins with the formation or liberation of foul-smelling products, 

 mercaptan, aromatic oxy-acids, etc. Rettger, 1908, in his 

 "Studies on Putrefaction" claims that not all obligate anaerobes 

 have the property of producing putrefaction and has divided the 

 strict anaerobes into four classes, in so far as their bio-chemical 

 characters are concerned, as follows. 



First, those that produce very little or no putrefactive changes 

 or fermentation with evolution of gas; second, those that have a 

 strong putrefactive action on native proteins but fail in fermen- 

 tative properties; third, those which are primarily fermentative 

 organisms and whose putrefactive functions are very slight or 

 perhaps absent; and fourth, those which have very marked 

 putrefactive and fermentative properties. Herter, 1907, ascribes 

 marked putrefactive properties to Clostridium Welchii and regards 

 it as being largely responsible for certain intestinal disturbances 

 although he uses the term putrefaction in a much broader sense. 

 Passini, 1905, also asserts that the bacillus of gaseous phlegmon 

 produces an abundance of indol when grown in pure culture on 

 blood serum. This is contrary to my observations on indol 

 production. Tissier and Martelly, 1902, claimed that C. per- 

 fringens isolated from putrefying meat and resembling Clostridium 

 Welchii had a decided putrefying action on blood fibrin although 

 the action was slow. Notwithstanding these views, using the 

 foregoing classification of Rettger's (1908), Clostridium Welchii 

 from my observations on the action of sugar-free native proteins 

 would fall in his third class of anaerobes, namely "primary 



