GENERAL SYSTEMATIC BACTERIOLOGY 219 



transferred to this genus from other genera, for it is quite conceivable, 

 that inasmuch as Vibrio syncyaneus Ehrenberg was probably the first 

 species of Vibrio sufficient^ described so that it can be certainty recog- 

 nized and identified today, it might be designated as the type of Vibrio. 

 In other words, if it is to be accepted as a type, it should be for Vibrio and 

 not for Bacterium. The form from yellow milk quite certainly should be 

 placed in the genus Bacillus. Bacterium aeruginosum is so closely rela- 

 ted to Bact. syncyanewn that they probably should be placed in the 

 same genus. It would certainly be unwise to choose the former as the 

 type, as there might well be question as to whether it did not belong 

 likewise in the genus Vibrio. It would seem that stability of nomen- 

 clature would not be conserved by the choice of any one of these as a 

 type species. 



If Bacterium is to be retained as a bacterial genus, it seems necessary 

 to pick the type species from those described subsequently to 1872. 



Lister (1873, p. 408) gave the name Bacteriuin lactis to an organism 

 responsible for lactic acid fermentation. "While his description may not 

 be sufficiently accurate to enable us to determine with certainty whether 

 he described the lactic streptococcus or one of the aerogenic lactic 

 bacilli, (such as Bacterium aerogenes) now generally regarded as 

 belonging to the colon-typhoid group, it is probable that the former 

 should be the interpretation. Bacterium lactis became Streptococcus 

 lactis and is not available as a type. 



Lankester (1873, p. 13) described a "peach coloured Bacterium" 

 from water under the name Bacterium rubescens. The description makes 

 it evident that he was working with organisms belonging to the group 

 of forms containing bacteriopurpurin, that is, to the group of sulfur 

 bacteria. The description further makes it evident that he was not 

 dealing with a pure culture. He dilates upon its variability, the appear- 

 ance of rods and spirals, and motile and non-motile cells, etc. Certain 

 of the forms were quite certainly previously described under other 

 names. Cohn wrote Lankester (1874, p. 399) that his organism was 

 the Monas Okeni Ehrenberg, the Clathrocystis roseopersicina of Cohn. 

 While Lankester combated Cohn's statements, modern knowledge 

 of the group would seem to justify them. Certainty the recog- 

 nition of Bacterium rubescens as a type species would be unwise. 



Warming (1875) described several species of Bacterium from the 

 water on the coast of Denmark. These were Bacterium griseum, Bact. 

 litoreum, and Bact. fusiforme. They were not grown in pure cultures 

 and apparently are not identifiable with certainty. 



