Severe losses are caused in some types of cheese by the growth of spore-forming anaerobes. The species most commonly involved is Clostridium butyricum and its variants, but other clostridia such as Cl. sporogenes (Bacillus putrificus of Dorner (1)) may also be concerned. Existing methods for the study of the properties of these organisms are inadequate, a fact on which Rosenberger(2) has commented. This work has been particularly concerned with devising a medium suitable for all clostridia, which is clear, simple to prepare, and which requires no special anaerobic precautions in its use.