CHANGES PRODUCED BY A SAPROPHYTIC ANAEROBE 375 



The organism would be considered to be proteolytic in its 

 action upon protein-containing media. Gelatin is liquefied rapid- 

 ly and completely. Inspissated serum is rapidly cleared, fol- 

 lowed by nearly complete digestion. In alkaline meat media 

 there is a rapid growth with the development of much ga.s and a 

 distinct!}^ unpleasant but not putrefactive odor. There is slight 

 digestion of the meat at the surface. This, however, was not 

 marked in any of the cultures. The surface layers of the meat 

 are darkened, while the lower layers retain their original color. 

 There is a heavy, whitish growth of bacteria on the surface of 

 the meat in very old cultures. About 1 or 2 mm. below the sur- 

 face is a blackened zone. Traces of hydrogen sulphide are found 

 in meat cultures. The liquid remains neutral or slightly acid 

 and the particles of fat on the surface appear to be partially dis- 

 integrated. Growth in Von. Hibler's brain media is very similar. 



Growth in milk is rapid. There is very little or no gas formed. 

 The casein is thrown down in a soft clot which is usually com- 

 pletely digested within four days. With some of the cultures, 

 however, digestion is never complete. The whey separates and 

 in a short time becomes of a clear light amber color, or yellowish 

 and turbid, according to the culture. The reaction is neutral or 

 sUghtly acid on standing, and the fat layer becomes disintegrated, 

 probably due to saponification. The cultures have a strong 

 cheesy to butyric acid odor. Some of the cultures are somewhat 

 more putrid and upon long standing, especially if enclosed in a 

 jar, there is a sUght odor of ethyl-but\Tic or of valerianic acid. 

 Cultures seem to differ considerably in this respect with age. 



In the egg medium, made according to the formula given by 

 Robertson (1916), the organism grows slowly. The first indica- 

 tion of growth is the appearance of blackening on the bottom of 

 the tube. This is followed in some cases by the formation of a 

 soft, yellowish clot which becomes fissured and may settle out, 

 leaving a clear, yellowish, transparent fluid. Some of the cultures 

 do not cause coagulation even on long standing, and those cul- 

 tures which form a clot, fail to produce further change, except in 

 a few cases, in which there is a marked shrinking of the clot. If 

 the medium was made sUghtly acid nearly all the cultures caused 



