48 R. E. BUCHANAN 



b. Cells typically Gram-positive. All non-motile. 



(1) Usually microaerophilic. Not typically growing well 



on the surface of laboratory media. Without meta- 

 chromatic granules. 



(a) Non-pathogenic lactic acid bacilli. 



Genus 8. Lactohacillus 



(b) Pathogenic, slender, small rods, not lactic acid 



formers Genus 9. Erysipelothrix 



(2) Aerobic rods, frequently showing metachromatic gran- 



ules or irregular staining. ..Genus 10. Corynebacterium 



Genus 1. Pseudomonas Migula, 1894, p. 237, emended 



Synonyms : 



Bacterium Ehrenberg emended Cohn, 1872, p. 167 

 Bactrillum Fischer, 1895, p. 139 

 Arthrohactrinium Fischer, 1895, p. 139 

 Arthrobactrillum Fischer, 1895, p. 139 

 Bactrinius Kendall, 1902, p. 484 

 Bactrillius Kendall, 1902, p. 484 

 Denitromonas Jensen, 1909, p. 314 

 Liquidomonas Jensen, 1909, p. 332 



Rod-shaped bacteria, never spiral, usually motile by means of 

 polar flagella or rarely non-motile. Aerobic and facultative. Fre- 

 quently liquefying gelatin. Without spores. Gram stain variable. 

 Usually producing a water-soluble pigment which diffuses through 

 the medium as a green, blue, purple, or brown or in some cases a 

 yellow pigment. Fermentation of carbohydrates usually not active. 



The type species is Pseudomonas aeruginosa (Schroeter) Frost? 



It is difficult to determine whether the generic names Pseudo- 

 monas or Bacterium should be used here. There is evidence 

 that the latter is historically valid for this genus, but it has 

 not generally been so accepted. The generic name Bacterium 

 has been used in some seven different senses. 



1. Bacterium. The conception held before the work of Cohn, 

 1872. Relatively rigid cells or chains of cells, not flexible, 

 motile, motion usually oscillatory. The name was used in this 

 sense by Ehrenberg (1828), Dujardin (1841), Perty (1852) and 

 Davaine (1868). 



