CLASSIFICATION OF BACTERIA 25 



which possess flagella distributed all over the cell-wall 

 and are motile, the genus Bacterium consisting of those 

 rod-like forms which are devoid of motile organs. The 

 presence or absence of cilia is found, however, to be a 

 variable character, even in the same species, an organism 

 at one time appearing to be without them, while, when 

 grown on another medium and at a different temperature, 

 it may become motile and possess cilia. The scheme, 

 if rigidly carried out, would necessitate much alteration 

 of existing names, and would be likely to lead to con- 

 fusion. It is perhaps best at present to include the 

 non-sporing, rod-shaped organisms in the genus Bac- 

 terium, those with genuine endospores being placed in 

 the genus Bacillus. The genus Pseudomonas includes rod- 

 like forms with flagella attached only to the ends or 

 poles of the cell. Planococcus embraces motile micro- 

 cocci ; Planosarcina, motile sarcinae. 



The Naming of Species. Botanists use two Latin 

 words when speaking of a plant, the first of which 

 denotes the genus and the second the species to which it 

 belongs : thus the botanical name of red clover is 

 Trifolium pratense ; of white clover, Trifolium repens, 

 both species being different, yet belonging to the same 

 genus. The same obtains when speaking of bacteria : 

 thus we have Bacillus subtilis for the hay bacillus, 

 Bacillus anthracis for the organism causing anthrax. 

 Unfortunately, this scheme of nomenclature has not been 

 strictly adhered to by many irresponsible workers at 

 bacteriology, but it is hoped that some day the chaos 

 existing in the naming of these organisms will disappear 

 and order take its place. Hundreds of species have 

 been described, and named by various writers in different 

 parts of the world, but much comparative work must be 



