228 GENERAL SYSTEMATIC BACTERIOLOGY 



The generic diagnosis used by Zopf and by Hueppe, and more com- 

 monly used than any other includes in the genus the rod-shaped organ- 

 isms which do not produce endospores. This was a natural emenda- 

 tion of Cohn's definition, as the Bacilli described by him were 

 endosporous. 



The definition of Migula excludes from the genus all motile rods. Cer- 

 tainly most of the organisms previously termed Bacterium by Cohn and 

 his predecessors were motile forms. Furthermore, motility is one of the 

 most variable of bacterial characteristics. This definition associates 

 in the same genus forms so distantly related as the tubercle and the 

 anthrax bacilli, and places in separate genera closely related organisms 

 of the intestinal group such as the colon bacillus and the organisms of 

 gassy milk. 



It might seem best to select some organism early named Bacterium 

 as the type and so word the generic diagnosis as to include this form 

 and the related species. But it should be described by the inclusion of 

 more than a single character, such as motility. E. F. Smith has 

 attempted to identify the Bacterium termo of Cohn, evidently intended 

 by this author to constitute the type of the genus. Smith states: 



Much discredit has been throwii on Bacterium termo in modern times, and it 

 has been left out of many classifications. However, if one examines into the 

 matter, there is no reasonable doubt as to what Cohn had in mind. His Bacter- 

 ium termo was a small schizomycetous organism capable of growing freely in 

 Cohn's nutrient solution, containing acid potassium phosphate and ammonium 

 tartrate. It produced therein short rods (single, in pairs or fours, joined end to 

 end) and roundish lobed white zoogloeae, together with a greenish fluorescence. 

 This is Cohn's statement and De Bary's. 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. (Schroter). In other words, it was a non-sporiferous green- 

 fluorescent organism possessed of a single polar flagellum, or, in some cases per- 

 haps, provided with paired or triple polar flagella. If we start with Cohn's 

 classification in the year 1872 we may keep the name Bacterium for schizomycetous 

 organisms of this type, and at the same time we shall not be doing any violence to 

 the older use of the word of Ehrenberg, who figures and describes this kind of an 

 organism. This the writer proposes to do, substituting Bacterium (Cohn emend.) 

 for Pseudomonas Migula and for more recent names proposed by others. 



Smith has attempted to follow Cohn's procedure in getting cultures 

 of Bact. termo and succeeded by inoculating Cohn's solution with water 

 into which beans had been thrown. A green fluorescent organism with a 

 polar flagellum and incapable of gelatin liquefaction was secured. 



It is interesting to note that by an entirely distinct line of reasoning 

 Vuillemin came to a similar conclusion. He notes that Ehrenberg 



