GENERAL SYSTEMATIC BACTERIOLOGY 47 



B. Rod shaped or filamentous, not spiral, no differentiation between the extremi- 



ties of the rods. 

 I. With or without spores, if the former not fusiform when sporulating. 



Bacillus 

 II. With spores, fusiform Clostridium 



C. Curved rods or spiral filaments. 



I. Not pleomorphic. 



a. Cells not sinuous. 



1. Cells rigid, not flexuous Spirillum 



2. Cells flexible Vibrio 



b. Cells with sinuous motion Spirochaete 



D. Cells filamentous, with differentiated base and apex. 



I. Without pseudo-branches. 



Genera. Leptothrix, Beggiatoa, Crenothrix and Phragmidiothrix. 

 II. With pseudo-branches Cladothrix 



Attention should be called to the merging of all rod-genera (except 

 Clostridium) into the genus Bacillus. This came in time to be the most 

 commonly accepted of the medical definitions of the term. 



Thaxter (1892) called attention to the existence of a new family 

 of bacteria which he named the Myxobacteriaceae. The organisms 

 belonging to this family show a more complex life history than the forms 

 more commonly studied. The rod shaped cells are associated in a 

 pseudo-plasmodium which in possession of motility resembles the Plas- 

 modium of a slime mold. The genera Myxohacter and Alyxococcus 

 were described. 



During the same year the work of Winogradsky (1892) called to at- 

 tention the important group of soil bacteria which oxidize ammonia 

 to nitrites and nitrites to nitrates. To his work we owe the generic 

 names Nitrobader, Nitrosococcus and Nitrosomonas. The genus Nevskia 

 was also described in the same year by Famintzin (1892) to include 

 certain rod shaped bacteria which developed peculiar branched or lobed 

 capsules due to the asymmetric deposition of the gummy material. 



During the year 1893 the only generic name proposed was Achroma- 

 tium by Schewiakoff for an organism of relatively monstrous propor- 

 tions, which in its content of oxalates (?) simulated in appearance 

 some of the sulphur bacteria. 



Freudenreich (1894) recognized three genera of Coccaceae, Micro- 

 coccus, Sarcina and Streptococcus with their usual definitions, and in 

 the Bacteriaceae the genera Bacterium and Bacillus, the latter with en- 

 dospores, the former without. 



