12 HILDA HEMPL HELLER 



and had little fermentative power. He (1913) identified as 

 B. amylobader strains which ferment cellulose. 



Pringsheim described C. americanum, which fixes nitrogen 

 less energetically than C. Pastorianum and ferments the same 

 sugars as that organism, besides mannitol, glycerol and lactose. 

 It will grow in open flasks; Bredemann terms it an anaerobe. 



Douglas, Fleming and Colebrook have described under the 

 name B. butyricus a medium sized bacillus that should be 

 assigned to this genus or to MuUifermentans. Mcintosh de- 

 scribes what may be the same strain. 



Prazmowski described under the name Clostridium polymyxa 

 an aerobic organism. The generic name has since been used 

 occasionally for aerobes. It must in future be restricted to the 

 group of anaerobic organisms which most strongly resemble the 

 first type described by Prazmowski, C. butyricum. 



There apparently remains abundant critical chemical and 

 systematic work to be done in the study of this important genus, 

 and such work should be performed with improved technique 

 and with cultures whose purity will stand criticism. 



Genus 2. Omelianskillus nov. gen. 



Clostridioideae that do not grow well in media containing much 

 protein, and may derive all their nitrogen from mineral salts. 

 Split cellulose or hemicellulose. Do not contain starch. Long 

 slender bacilU with spherical spores. Colonies may be produced 

 on potato slants; they are minute, yellowish and transparent. 

 Agents of plant putrefaction, found everywhere. 



Type species 0. hydrogenicus (the ferment of cellulose which 

 produces hydrogen, of Omeliansky) as described by OmeUansky 

 (1895 and 1904 b). Characters of genus. Probably several 

 species were studied by Omeliansky. In his later work he ad- 

 mits that the cultures studied by him were not pure. Another 

 type, 0. mcthanicus, similar to the above, is said to be the agent 

 of methane formation in cellulose fermentation. This species 

 may be assigned to the same genus. 



These organisms were isolated by growing them in a medium 

 free of organic nitrogen. There may be other genera of anaerobic 



