50 R. E. BUCHANAN 



short rods (single, in pairs or fours, joined end to end) and roundish 

 lobed white zoogloeae, together with a greenish fluorescence. It did 

 not appear in boiled fluids, i.e. was destitute of endospores (Cohn) 

 and the motile rods were killed by short exposure to 58°C. (Schroeter). 

 In other words, it was a non-sporiferous green fluorescent organism 

 possessed of a single polar flagellum, or in some cases, perhaps, provided 

 with paired or triple polar flagella. 



Smith attempted to follow Cohn's procedure in getting cul- 

 tures of Bact. termo and succeeded, by inoculating Cohn's solu- 

 tion with water in which beans had been thrown, in securing a 

 green fluorescent organism with a polar flagellum. He con- 

 cludes that the morphologically similar non-fluorescent forms 

 and the yellow bacteria should be included in this genus. 



Vuillemin by an entirely distinct line of reasoning came to a 

 similar conclusion. He notes -that Ehrenberg based his generic 

 description in part upon the type of cell motility, oscillatory. 

 Today, he states, we know this characteristic type of motion to 

 be due to the presence of polar flagella on short rods. He con- 

 cludes that the Bact. termo is closely related to Bacillus pyo- 

 cyaneus and accepts this as the type of the genus. 



Still a third Hne of evidence will lead to a similar conclusion, 

 i.e., a study of the species of Bacterium other than Bact. termo 

 recognized by Cohn and his coworkers. Three species pre- 

 viously described were placed in the genus Bacterium by Schroeter. 

 One of these was the Vibrio syncyaneus of Ehrenberg, the organ- 

 ism repeatedly described in literature as the cause of blue colora- 

 tion in milk. It is a polar flagellate rod. The name Bact. 

 aeruginosum is the earlier name applied by Schr5ter to the blue 

 pus organism, chosen by Vuillemin to constitute the generic 

 type. The organism termed Bact. xanthinum, however, belongs 

 to an entirely distinct group. 



It is evident therefore that there is historical justification for 

 E. F. Smith's emendation of the genus. The principal criticism 

 is the undue insistence upon motility. It would seem that an 

 organism morphologically similar but non-motile, showing the 

 same fluorescence and physiological characters should likewise 

 be included in the genus. 



