EVOLUTION AND CLASSIFICATION OF BACTERIA 455 



third, into which apparently are to be dumped all peritrichic 

 or non-motile, non-spore-forming saprophytes, is stated in the 

 report to consist primarily of the colon-typhoid-dysentery group. 

 It is particularly unfortunate that B. coli has been proposed as 

 the type of this genus, since the group which centers around this 

 organism is quite distinct from the majority of saprophytes 

 belonging in this family. In this matter they claim to be accepting 

 Jensen's emendation of the genus Bacterium; but they expand his 

 emendation to include his Denitrobacterium and also the Proteus 

 group, which Jensen named Liquidobacterium, and have actually, 

 therefore, proposed a new emendation. If B. coli is accepted as 

 the type of Bacteriurn it would be natural to use the generic name 

 only for the colon-typhoid group, leaving no place for the large 

 number of indefinite forms that the committee intends it to 

 include. 



Still more questionable is the genus Erwinia. This has been 

 named as a new genus by the committee without a type species 

 and therefore does not have a good standing. It is very doubt- 

 ful, indeed, whether peritrichic plant parasites are sufficiently 

 distinct from saprophytes to be put in a genus by themselves. 



It seems strange that the committee has not recognized the 

 genus Proteus Hauser, which is as distinct as several that they 

 have recognized. Although this genus is primarily saprophytic, 

 it has a fairly well defined type species, and is apparently distinct 

 from the colon-typhoid group. 



Family 7. Lactobacillaceae. There is very little reason for 

 putting the Bulgaricus type of organisms in a family by them- 

 selves. They do differ in many respects from the Gram-negative 

 rods — enough to justify the recognition of the genus Lactobacillus, 

 but hardly enough to furnish a basis for the establishment of a 

 new family. The very points of greatest distinction, granular 

 structure, occurrence of bud-like branches, and failure to de- 

 colorize by the Gram method, are points which suggest a relation- 

 ship to the diphtheria and tubercle organisms. So little is known 

 about the Lactobacillus group, however, that there is scant 

 justification for placing it in the Mycobacteriaceae, and the 



