GENERAL SYSTEMATIC BACTERIOLOGY 223 



as a generic character, and states that the vegetative cells are short 

 rods, little longer than broad, in the rounded form either solitary or 

 embedded in slime (Zoogloea), from which a motile form emerges. 

 Three species only are listed: Bad. termo Ehr., Bact. septichaemiae 

 and Bact. ckolerae gallinarum. The chromogenic species previously 

 listed here by Cohn and Schroter are transferred to the genus Bacillus. 

 Hansgirg (1888, p. 265) Hsted Bacterium as the second genus of the sub- 

 family Microbacteria, but with no diagnosis. De Toni and Trevisan 

 (1889, p. 1020) give the following generic diagnosis: 



Bacterium Ehrenb. (1830) emend. Trev. Bacterii et Bacilli species Auctorum. 

 Baculi vulgo brevis, interdum brevissimi, ut plurimum ellipsoidei, raro cylin- 

 dracei, apicibus obtusis, recti. Sporae (arthrosporae) globosae, e coccorum 

 metamorphosi ortae. 



The genus is included in the subfamily Baculogenae and the tribe 

 Bacilleae. In all, thirty-four species are described. Of these Bact. 

 aceti (Kuetz) Lanzi, Bact. Pasteurianum (Hanson) Zopf, Bact. allan- 

 toides Trev. and Bact. Balhianii Billet are noted as particularly typical. 

 The genus is divided into two primary groups, Bacteria achroa (22 

 species) and Bacteria chromogena (12 species). The first group is again 

 sub-divided into Species Zymogena (8 species, mostly acetic acid bac- 

 teria), Species saprophyticae (13 species) and Species anthrophobiae (1 

 species). The second group is divided into Species granula sulphuris 

 nulla secernentes (7 species) and Species granula sulphuris secernentes 

 (5 species). Baumgarten (1890) abandoned the genus, including all rod 

 forms in Bacillus. Billet (1890), p. 23) s^ys "Formes rectilignes Bac- 

 terium, element 1 a 5 fois plus long que large." Sternberg (1892, p. 18) 

 states: "This genus, established by Dujardin, is now generally aban- 

 doned, the species formerly included in it being transferred to the genus 

 Bacillus." Ludwig (1892) included in Bacterium rod-shaped elliptical 

 organisms, not in long filaments, not embedded in slime, and differen- 

 tiated from Bacillus by lack of endogenous spores. Freudenreich (1894) 

 defines a Bacterium as a rod without endospores or with arthrospores. 



Migula (1894, p. 236) radically emended the genus to include only the 

 non-motile rods, i.e., those forms with shorter or longer cylindric cells, 

 sometimes forming filaments, without flagella, endospore formation ob- 

 served in many species, in others apparently completely lacking. He 

 states: *' Bacterium Cohn.ZeUen ohne Bewegungsorgane oft mit Endo- 

 sporenbildung. (Z. B. Bacterium Anthracis)." He notes that about 

 200 species are known. 



