GENERAL SYSTEMATIC BACTERIOLOGY 201 



A large number (228) of species are described. Billet (1890, p. 23) 

 described Bacillus as "Formes rectilignes, element 5 a 10 fois plus long 

 que large." 



Bamngarten (1890) was apparently the first to use the generic name 

 Bacillus to include all rod-shaped, "monomorphic" bacteria, prac- 

 tically merging with it the genus Bacterium. This conception was 

 adopted by Sternberg (1892, p. 18) who defined the genus as follows: 



Rod-shaped and filamentous (not spiral) bacteria in which there is no differen- 

 tiation between the extremities of the rods; reproduction by binary division in 

 a direction transverse to the long axis of the rods, or by binary division and the 

 formation of endogenous spores; rigid or flexible, motile or non-motile. 



This use has led to the rapid "vulgarization" of the term Bacillus 

 until it is frequently now noted as being used in two senses, a general 

 sense with reference to shape, and as a genus name. This has con- 

 tributed to much confusion in the literature. 



Ludwig (1892) defines the genus as containing small rods which pro- 

 duce endogenous spores. 



Clements (1894, p. 27) fists four species, with the following generic 

 description : 



Cells cylindrical, straight or curved, motile, filaments present at time of spore 

 formation, falling into small cells as soon as the endogenous spore is formed. 



ISIigula (1894, p. 237) emended the genus Bacillus Cohn, the diagnosis 

 reading "ZeUen mit liber den ganzen Korper angehefteten Bewegungs- 

 organen, oft mit Endosporenbildung. (Z. B. Bacillus subtilis Cohn.)" 

 Migula (1895, p. 25) later elaborated this conception. He based his 

 principal generic designations upon differences in flagellation. Accept- 

 ing B. subtilis as the generic type, he characterized the genus as made 

 up of straight rods with flagella scattered over the entire cell body. 

 Sporulation and filament formation he considered secondary to 

 flagellation. 



The second emendation in 1895 of Bacillus was that of Fischer (1895, 

 p. 140). This author rejects Migula's use and states: 



Unbeweglich, ohne Geisseln, mit Endosporen in unveranderten, nicht spindeli- 

 gen Oder kopfigen Stabchen; eine schwache allseitige Vergrdsserung derStabchen; 

 bei der Sporenbildung kommt zuweilen vor. Sporen in der Mitte oder am Ende 

 der Stabchen, Bacillus anthracis Cohn Bacillus Carotarwn A. Koch. 



