386 JAMES M. SHERMAN 



an extended period the growth is seen to become very heavy, bare- 

 ly below the surface of the agar. In a suitable nutrient broth a 

 heavy shmy growth occurs at the bottom and the whole broth be- 

 comes turbid, with the usual exception of a narrow clear zone at 

 the surface. Milk is rendered slowly acid and is usually curdled 

 in from one to two weeks at 30°C. Growth in pepton milk is much 

 better, curdling taking place in from four days to one week at 

 30°C. Small bubbles of gas may sometimes be seen in the curd. 

 Gelatin is not liquefied. Glucose, lactose, maltose, sucrose, gly- 

 cerol and salicin are fermented; raffinose, inulin, and mannitol 

 are not. 



One of the outstanding characteristics of this organism is the 

 production of a large amount of catalase. Attention has pre- 

 viously been called to the relatively large amount of catalase which 

 is found in Swiss cheese (Sherman 1919). The group of organ- 

 isms herein described is the one which was shown to give this char- 

 teristic to cheese of the Emmental type. 



Reference to the products produced by this bacterium indi- 

 cates that it belongs to the group of proprionic acid bacteria 

 which was described by Von Freudenrich and Orla- Jensen. Lac- 

 tates are fermented with the production of volatile acids, including 

 propionic and acetic, and carbon dioxide. Also in the fermenta- 

 tion of lactose, volatile acids and carbon dioxide are produced. 



Relation to previously described types 



Whether this organism is identical with any of the types iso- 

 lated by Von Freudenrich and Orla-Jensen cannot be definitely 

 stated at this time. In general it appears to agree quite closely 

 with their description of Bact. acidi-propionici (a) which they con- 

 sidered to be the true cause of the development of eyes in cheese. 

 A few points, however, in their description do not agree with the 

 characteristics which we have observed in our organism; they 

 state that it causes no visible change in milk, whereas our organ- 

 ism in litmus milk develops an acid reaction after several days and 

 causes coagulation on longer incubation. Further, from their re- 

 sults on the production of volatile acids it was noted that only a 

 small amount of these substances was produced from glycerol. 



