220 GENERAL SYSTEMATIC BACTERIOLOGY 



Dallinger (1878, p. 159) studied Bacterium termo microscopically, 

 demonstrating motility to be due to a terminal flagellum. It is defined 

 in the sense of Cohn. 



In 1875 Cohn included the genus in the tribe Glaeogenae. It was 

 defined as having cylindrical cells, without phycochrome, very small, 

 cells united in glairy families, amorphous when in repose, or entirely 

 free, never disposed in filaments. In this revision he accredited the 

 genus to Dujardin rather than to Ehrenberg. Magnin (1878, p. 80) 

 follows Cohn exactly. The diagnosis reads : 



Bacterium, Duj. emend. Cells cylindrical or elliptical, free or united in pairs 

 during their division, rarely in fours, never in chains, sometimes in zoogloeae, 

 having spontaneous movements, oscillatory and very active, especially in media 

 rich in alimentary material and in presence of oxygen. 



The species are divided into three groups: 



1. The bacteria of putrefaction (Bad. termo Ehr. and Bad. lineola 

 Cohn). 



2. The bacteria of lactic and acetic fermentations, and 



3. The chromogenic bacteria (including Bad. xanthinum Schroter, 

 Bact. syncyaneum Schroter, Bad. aeruginosum Schroter, and Bad. 

 brunneum Schroter). 



Of the species, the chromogenic forms can for the most part still 

 be readily recognized. 



Lanzi (1876, p. 256) designated the organism responsible for acetic 

 fermentation Bacterium aceti. 



Trevisan (1879, p. 136) gives the following synonymy and description: 



Bacterium Ehrenb. (1830 non 1828) emend Cohn (Beitr. I Heft 2, p. 177); 

 (Chromatium Perty 1852; Zoogloea Cohn 1853; Rhabdomonas, Cohn 1875). Cel- 

 lulae breviter cylindricae, vel ellipsoideae, vel fusiformes. Multiplicatio divisione 

 cellularum vegetativa semper ad eandem directionem longitudialem. 



The species recognized are Bad. aceti Lanzi 1876, Bad. termo Ehrenb., 

 Bad. lineola Cohn, Bad. tremulans Trevisan, Bad. catenula Dujard., 

 Bad. pundum Ehrenb., Bact. synxanthum Schroeter, Bad. syncyaneum 

 Schroeter and Bact. aeruginosum Cohn. 



The generic description of Bacterium by Luerrsen (1879, p. 20) does 

 not assist in fixing a type species. 



Van Tieghem (1879) described a Bacterium lucens from the surface 

 of liquids. 



Sternberg (1880, p. 80) in his translation of Magnin's (1878) text on 

 the bacteria gives the following characterization of the genus Bacterium : 



