PROSPECTS FOR A NATURAL SYSTEM OF CLASSIFICATION OF BACTERIA 



shows a distinct tendency to differentiation as manifested by the 

 occurrence of spore formation, branching, etc. 



Now the foundation of a classification chiefly on ecologic principles 

 is undoubtedly very dangerous, as is clearly demonstrated by the ob- 

 vious impossibility to apply such a scheme to the classification of 

 higher organisms, where a more scientific taxonomy can be achieved 

 on the basis of characters which have an undisputably phylogenetic 

 value. It is therefore not surprising that a closer inspection of Pribram's 

 system reveals its inadequacy. Thus, in order to defend the motility 

 of a bacterium as a typical feature of an aquatic habitat Pribram has 

 to resort to the enormity that the occurrence of peritrichous flagella 

 amongst the representatives of the third group does not conflict with 

 their supposed 'sessile' character, since here the flagella do not serve 

 the purpose of locomotion but just act as organs to replenish the food 

 supply.* 



Moreover we find amongst the Algobacteria numerous species which 

 are immotile, as well as organisms like various Micrococcus and Sarcina 

 species which according to their habitat belong to the second subclass. 

 And how can the author justify the inclusion of the peritrichous genera 

 Serratia (and Hillhousia?) in the first subclass? The same holds, al- 

 though for different reasons, for the genera Myxococcus, Chondromyces 

 and Polyangium. The dissemination of a natural group like the 

 Thiorhodaceae over three orders should not remain without protest 

 and no investigator of this group of organisms will tolerate the plac- 

 ing of Rhabdomonas (N.B. as type genus) between the genera Beggiatoa 

 and Thioploca and this merely on the basis of an alleged contractility 

 of the cells. 



Our criticisms of the second subclass are based for the greater part 

 on the extreme heterogeneity of its constituent units. As for the second 

 family our objections are substantially the same as those which have 

 been brought forward in connexion with our review of Enderlein's 

 subfamily of the Eisenbergiinae. We might remark in this connexion 

 that all motile acetic acid bacteria (Ulvina spec.) which have been 

 studied with respect to the mode of insertion of flagella have proved 

 to be polar. In consequence their inclusion in the subclass Eubacteria 

 conflicts with the first mentioned character in the diagnosis of this 



* We have found the same critical remark in the attractive review of Pribram's 

 monograph by C. Stapp. Zentralbl. Bakt. Parasitenk. Abt. II, 89, 514, 1934. 



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