534 HILDA HEMPL HELLER 



to live in the absence of free oxygen has been developed by too 

 many types to make it a character of value. But fewer types 

 have developed a susceptibility to free oxygen. The classifi- 

 cation proposed by the Committee (1920) places certain anaerobic 

 forms such as the anaerobic leptotrichia with aerobic forms that 

 are patently their relatives. The Committee justly assigns 

 generic rank to the obhgately parasitic, non-sporulating, shyly 

 growing, fusiform anaerobes. They do not mention the anaero- 

 bic cocci, which should probably be included with the Coccaceae. 

 The Committee does not mention any anaerobic non-sporulating, 

 non-fusiform rods. In my collection there are two such strains 

 (B. egens and one of my own isolation) which do not readily 

 attack milk, and these organisms do not fall into any of the 

 groups designated in the key, which follows the Committee's 

 classification. B. necrophorus, again, of whose phylogenetic 

 position I am in doubt, does not sporulate. 



Fusiform bacilli have probably recently acquired an anaerobic 

 habit through parasitism. Thus Larson and Barron describe a 

 strain of these organisms which became adapted to growth under 

 aerobic conditions. Analogous is the behavior of B. ahortus- 

 bovis, which frequently refuses to grow aerobic ally when first 

 isolated but later accustoms itself to living in the presence of 

 oxygen. The anaerobic habit may, in some cases, be due to a 

 sensitiveness to carbon dioxide instead of oxygen. Curtis has 

 described a motile curved anaerobic rod which he isolated from 

 uterine discharges. The phylogenetic position of this organism 

 is in doubt. So also is the position of the branching anaerobes 

 B. ramosus and B. furcosus of Veillon and Zuber, and the influ- 

 enza-bacillus-like rod isolated from an abscess by Russ. Tunni- 

 cliff reports anaerobic rods from rhinitis and from bronchitis 

 patients; and TunnicUff, Plotz and his co-workers, and Dick 

 and Henry, report anaerobic organisms in the blood of fever 

 patients. But these organisms grow slowly and do not resemble 

 the chemically active anaerobic rods. We are justified in con- 

 cluding that an organism which has lived as a saprophyte or 

 parasite in the tissues or in the uterus may owe its anaerobic 

 habit to such residence. There are several reasons why we should 



