ing with the medium, spherical, terminal, swelling the cells. Young cells are motile, the motility disappearing with sporulation; flagella not demonstrable. Young vegetative cells are colored wine-red with iodine solu- tion. Gram-positive, becoming Gram-labile on sporulation. Gelatin (plus asparagine) : Liquefaction in 6 to 10 days. Medium remains perfectly clear. Asparagine agar deep colonies: Grayish white, delicate, cottony, with fine radial outgrowths. Asparagine agar surface colonies (ana- erobic): Poor, delicate, translucent, filmy, scarcely discernible growth. Cellulose-liver broth: Solution remains visibly clear and does not darken with age. Occasionally, large gas bubbles arise. Milk: Soft coagulation in 24 hours. Amor- phous clot shrinks and settles, forming a yellowish red to orange sediment with tur- bid supernatant whey. Indole not produced. Hydrogen sulfide produced in trace amounts in inorganic solutions. Maltose, mannitol, lactose, glucose, su- crose, galactose, fructose, starch, salicin, glycerol and inulin not attacked. Cellulose, apparently the primary carbon source, is only weakly attacked by pure cul- tures with the production of hydrogen and carbon dioxide. Yellow pigment not ob- served in the presence of cellulose (see Clos- tridium dissolvens) . Nitrites not produced from nitrates. Ammonia not produced. Brain medium: No digestion or blacken- ing. No visible evidence of growth. Non -pathogenic for mice; effect on other animals not recorded. Anaerobic. Grows at 25 to 30 mm mercury pressure. Optimum temperature, between 37° and 42° C. Optimum reaction, between pH 7.0 and 7.4. Grows between pH 6.0 and 8.4. Distinctive characters: Ability to liquefy gelatin (with asparagine added), to coagu- late milk, producing an orange sediment, and to grow in media containing asparagine without requiring the presence of cellulose. Spores resist heating at 100° C. for 90 min- utes. Comments: This species was apparently first isolated and studied in pure culture by Clausen {op. cit., 1931, 40 and 54). From his studies he concluded that Omeliansky's Wasserstoffbacillus and Methanbacillus are but a single species and that the gaseous fermentation products are H2 and CO2 , not methane; the production of methane ob- served by Omeliansky was effected by the symbiotic forms or other contaminants al- ways present in Omeliansky's cultures. Clausen's evidence is quite convincing, and the organism is presented here from his de- scription. Source: Isolated from human, cow and horse excreta, from the stomach contents of cows, from cheese and from soil. Habitat: Found in the intestinal canals of animals and presumably thence widely disseminated in soil. 86. Clostridium dissolvens Bergey et al., 1925. (Bacillus cellulosae dissolvens Khouvine, Ann. Inst. Past., 87, 1923, 711; Bergey et al.. Manual, 2nd ed., 1925, 344.) dis.sol'vens. L. part. adj. dissolvens dis- solving. Slender rods, ranging from 2.5 to 12.5 mi- crons in length, occurring singly and oc- casionally in pairs, but not in chains. Spores ovoid, terminal, swelling the cells. Non- motile. Gram-negative. Cellulose is digested by the formation of an endocellulase which acts only when the bacteria are attached to the cellulose. Sac- charides and CO2 , Ho , ethyl alcohol and acetic, lactic and butyric acids are pro- duced from cellulose. A yellow pigment is produced in the pres- ence of cellulose. Glucose and carbohydrates other than cellulose not fermented. Anaerobic. Grows between 35° and 51° C. without a definite optimum. For the thermophilic strain of Khouvine, see Clostridium thermo- cellum Viljoen et al. Not pathogenic for guinea pigs. Distinctive character: Grows only in me- dia containing cellulose, in the presence of which it produces a yellow pigment.
