GENERAL SYSTEMATIC BACTERIOLOGY 65 



b. Cells straight rods, non-motile. 



Genus Rhodobacterium 



c. Cells motile rods Genus Rhodobacillus 



d. Cells short, bean or comma shaped, monotrichous, actively motile. 



Genus Rhodovihrio 



e. Cells spiral, actively motile by means of a cluster of polar flagella 



Genus Rhodospirillum 



This work of Molisch is practically the only work of importance on 

 these bacteria since the first formulation of description and the group- 

 ing together of these organisms by Winogradsky. 



Other genera of bacteria described in 1907 include Pedioplana, a 

 motile organism occurring in tetrads, named by Wolff; Thioploca a fila- 

 mentous sulphur organism related to Beggiatoa, named by Lauterborn; 

 Myxohacillus, Myxokokkus and Pleimohacterium, OTganisuis producing 

 gums and slimes in sugar vats, named by Gonnermann ; and Borrelia 

 for the spirochetes of relapsing fever named by Swellengrebel. The 

 last named classifies the spiral organisms as follows : 



Swellengrebel's Classification of the Spirillaceae (1907) 



Cells with rounded tips, constituting any part of a spiral. 

 I. Subfamily. Spirillaceae. (nov. fam.) Cells are not jflexible. Genera, 

 Spirillum and Vibrio with diagnoses of Migula. 

 II. Subfamily. Spirochaetaceae (nov. fam.) Cells are flexible. 



a. Cells without cilia, with periplastic appendage well developed and often 



with an alveolar structure. Sometimes there is a band of myonemes 



in the appendage Spirochaeta Ehrenberg 



Type Spirochaeta plicatilis Ehrenb. S. balbianii placed here provision- 

 ally. 



b. Cells with one cilium at one end, sometimes at both extremities, which 



is a prolongation of the "calotte," the appendage has been demon- 

 strated sometimes Treponema Schaudinn 



Types (iS. buccalis, Tr. pallidum). 



c. Cells with peritrichous cilia Borrelia n. gen. 



Type, Sp. gallinarum. 



Ellis in 1907 as a result of studies on the iron bacteria came to the 

 conclusion that they should be separated into two principal groups 

 in accordance with the following scheme : 



Ellis' Grouping of the Iron Bacteria (1907) 



I. Reproduction by external abstriction of conidia : 

 Lepiothrix ochracea 

 Gallionella ferruginea 

 Spirophyllum ferrugineum 



