SUBGROUPS AND GENERA OF THE BACTERIACEAE 35 



S. Bacillus. Rods motile by means of peritrichous flagella, 

 spores may or may not be produced. The following authors 

 have recognized this definition; Migula (1894, 1895, 1897, 1900, 

 1904), Chester (1901), Kendall (1901), A. J. Smith (1902), E. F. 

 Smith (1905), Ellis (1909), Frost (1911), and Schneider (1912). 



4. Bacillus. Rods, non-motile, producing endospores. Fischer 

 (1895), Lotsy (1907). 



5. Bacillus. Any rod-shaped organism. Baumgarten (1890), 

 Sternberg (1892), Mace (1897), Hewlett (1898), and Matzuschita 

 (1902). 



6. Bacillus. Any motile rod. Conn (1909). 



Vuillemin (1913) has claimed that the name Bacillus has been 

 so vulgarized by the bacteriologist because of the number of 

 definitions that it should be abandoned as a generic designation. 

 It is, of course, true that bacillus is used as a common designa- 

 tion of all rod-shaped bacteria, but this should not invalidate 

 the use of this term as a generic name any more than the use 

 of Chrysanthemu7n or Aster as genera by botanists is interfered 

 with by the common names chrysanthemum and aster. 



In some form or with some definition the genus Bacillus should 

 be retained. The type practically always accepted is B. suh- 

 tilis. The definition of Fischer should therefore be abandoned 

 as including only non-motile forms. He would exclude from 

 the genus its first described species. The original description 

 of Cohn is scarcely sufficient, for much stress was laid upon cell 

 grouping and length of cell and not upon other characters. The 

 use of Migula's diagnosis, including in the genus all rods with 

 peritrichous flagella, is the cause of great confusion. It brings 

 into the genus such discordant types as the hay bacillus and 

 the typhoid bacillus while it excludes the anthrax bacillus so 

 closely related to the hay bacillus. Migula's definition should 

 be abandoned as not based upon natural affinities. The defini- 

 tions which would include all rods in the genus Bacillus have 

 the merit of simplicity. When, however, organisms so diverse in 

 characteristics as the tubercle bacillus, the typhoid bacillus, the 

 tetanus bacillus, and the anthrax bacillus are all included in one 

 genus the simplicity is more apparent than real. The existence 



