Differentiation of Certain Genera of Gram Negative Bacteria 517 



attempts, was never al^le to demonstrate convincingly tliat Group 

 I possessed, at any time, flexing cells, and further work will be 

 required to settle this problem. Hayes's three motile (peri- 

 trichous) rods show very little similarity to either of the other 

 two groups and probably belong to another genus. 



The abo\'e determinative scheme has now been in use at 

 Terry for a number of years and has been used during this time 

 by several workers, e.g. (40, 20, 47), in their examination of 

 thousands of isolates from marine sources. By its use they have 

 usually been able to classify their cidtures, at least to the generic 

 level, quite quickly. In addition, we have examined over 200 

 named strains from Type Culture Collections and individual 

 workers, which have included Fseudomonas, Achromobacter, 

 Vibrio, Aeromonas, Xanthomonas and Flavobacterium sp. In most 

 instances we have been able to identify them unequivocally by 

 our scheme although in some cases this classification has dif- 

 fered from that originally given. Our scheme has also been in use 

 for some time in other laboratories and other workers, to whom 

 the scheme has been demonstrated at Torry, have published data 

 showing its general usefulness ( 9, 57 ) . It is of course a determina- 

 tive scheme and does not claim to express any phylogenetic re- 

 lationships between the groups. 



ACKNOWLEDGMENT 



The author wishes to thank Mr. Hodgkiss for the electron 

 microscope preparations and Dr. Floodgate for his analysis, using 

 the Sneath's formula of Hayes data on the pigmented rods from 

 marine sources. 



REFERENCES 



1. Adams, J. N., Williams, J. and Payne, W. J.: Agarbacterium algini- 



cum; the appropriate taxonomic designation for Alignomonas alginica. 

 /. Bad., 8i: 162-163, 1961. 



2. AsAi, T., Okumura, S. and Tsunoda, T.: On the classification of the 



a-ketoglutaric acid accumulating bacteria in aerobic fermentation. 

 /. Gen. Appl. Microbiol., 3:13-33, 1957. 



3. Bagge, J. and Bagge, O.: Virhrio anfiuillarum som arsag til ulcussygdom 



hos torsk (Gadus callarias, Linne). Nord. Vet. Med., 8:481-492, 

 1956. 



