270 S. ORLA-JENSEN 



Buchanan (1917) sets up six orders of bacteria. I shall not 

 undertake to discuss whether he is right or not, but only point 

 out that if we follow him consistently the order Eubacteriales 

 is necessarily to be divided into two orders, which we may call 

 Pseudomonadales and Peritrichinales, as these two groups are 

 by no means more closely related than Pseudomonadales and 

 Thiohacteriales (the sulphur bacteria), forming together the 

 cephalotrichic bacteria. Again to reduce the seven orders 

 thus estabhshed to the corresponding families would perhaps 

 not be a quite unsatisfactory solution of the family problem. 



If we class together the genera which I have set up — with the 

 amendments occasioned by my experience and that acquired by 

 other researchers — into the above-mentioned two orders, we 

 arrive at the following general synopsis: 



Order 1: Pseudomonadales Order 2: PeritricMn.alcs 



1 Methanomonas 1 Thermobacterium 



2 Carboxydomonas 2 Streptobacterium 



3 Hydrogenomonas 3 Streptococcus 



4 Nitrosomonas 4 Betabacterium 



5 Nitromonas 5 Betacoccus 



6 Azotomonas 6 Propionibacterium* 



7 Rhizomonas 7 Microbacterium* 



8 Acetimonas 8 Tetracoccus 



9 Fluormonas 9 Coccus 



10 Photomonas 10 Bacterium* 



11 Spiromonas 11 Bacillus* 



12 Clostridium* 



As for the position of Rhizomonas {Rhizohium) in the system, 

 I accept the proposal of the Committee, to place it next to 

 Azotomonas (Azotohacter) . I have myself really met with forked 

 cells in different genera of bacteria and thus cannot attach a 

 decisive, systematic importance to the furcation. After the 

 researches of Barthel (1917) and those of Burrill and Hansen 

 (1917) it must now be considered as certain that Rhizomonas 

 is lophotrichic, and as a Gram-negative, lophotrichic nitrogen 

 gatherer it ranks naturally with Azotomonas. 



On the other hand, I cannot accept the proposition of the 

 Committee to give the acetic acid bacteria the generic name 



