GLUCOSE BOUILLON CULTURE IN SMITH FERMENTATION TUBE AT FOUR DAYS. CULTURE GROWN AT ROOM TEMPERATURE (20° TO 25° C.). GROWTH CONFINED ENTIRELY TO CLOSED ARM, WITH GAS COLLECTING AT TOP.] A more extended study is now being carried on in the Biochemic Division of the chemical changes which take place in hams during the process of souring, together with a further study of the chemical changes which result from the growth of the bacillus in the egg-pork medium. The results of this investigation will be given in a later paper. The bacillus described in this paper belongs to the class of putrefactive anaerobes, which are widely distributed in nature in dust, soil, and excrementitious matters. This group of bacteria contains both pathogenic and nonpathogenic forms. The former have received considerable attention, but the latter have never been thoroughly cleared up. The bacillus isolated from sour hams belongs in the latter category, being possessed of no pathogenic or disease-producing properties. It occurs in the dust and dirt of the packing house and finds its way into the hams in the various manipulations to which the hams are subjected. The bacillus described in this paper does not seem to correspond with any forms heretofore described. It differs from Klei bacillus (_Bacillus fœdans_) in the following important particulars: (1) It forms large terminal spores, whereas Klein’s bacillus formed no spores; (2) it will grow at a temperature of 34° F., while Klei bacillus did not grow below 50° F.; (3) it produces an acid reaction in culture media, while Klei bacillus gave a distinctly alkaline reaction; (4) it will grow on the ordinary nutrient media—gelatin, agar, and broth—without the addition of glucose, while Klein’s bacillus did not; (5) it peptonizes the casein in milk, whereas Klein’s bacillus had no action on milk; (6) it liquefies gelatin more rapidly, causing complete liquefaction after three weeks at 8° to 10° C., whereas Klein’s bacillus caused only partial liquefaction after eight weeks at 20° C.; (7) it can be conveyed from turbid broth cultures to new culture material by means of the platinum loop, whereas Klein’s bacillus could not be thus conveyed. For the bacillus described in the present paper the following name is proposed: _Bacillus putrefaciens_. PREVENTION OF HAM SOURING. As it has been shown that souring in hams results from the growth of a bacterium which is introduced into the bodies of the hams in the various manipulations which the hams undergo, the only way to eliminate souring in hams, as they are cured in the larger packing establishments, would be to cure the hams under aseptic or sterile conditions, which would, of course, be a physical impossibility.