Repoi^t on the Bacteriology of Water. 



289 



If we now attempt to discover this form among the species recorded 

 in Eisenberg, Mace, and Roux, there appear to be only the following 

 to choose from as the known liqnefying forms which produce the 

 characteristic green fluorescence in gelatine, or which possess any 

 green pigment at all:* — Bacillus fluorescens liquefaciens (Fliigge), 

 B. fluorescens liquefaciens minutissimus (Unna), B. fluorescens nivalis 

 (Schmolck), B. viscosus (Frankland), and B. termo (Duj. and Mace). 

 We will also notice B. aerojoliilus (Libor.) and B. chlorinus (Engelm.) 

 as being accompanied by a green colour in the cultures. We may at 

 once eliminate B. chlorinus, however, because, according to Engel- 

 mann's description (he called it Bacterium chlorinum), the green 

 colouring matter is in the cells, and these are much too large for our 

 form. The same applies to Van Tieghem's Bacillus viridis and B. 

 virens, and we are not concerned here with the discussion as to the 

 chlorophyll nature of the colour or the claims of these forms to be 

 regarded as Schizomycetes at all. 



B. aerophilus may also be readily eliminated, for, apart from the 

 large size of its filaments, it grows very slowly, and does not colour 

 the gelatine ; its green colour is confined to the colonies. 



B. fluorescens liquefaciens (Fliigge) presents startling points of 

 similarity with our form. 



It agrees in habitat, water and air, &c, as well as in the mean size 

 and union of the rodlets, and is motile. 



The colonies on gelatine plates are, like our form, round and de- 

 pressed in funnel form, and the very regular clear zone of liquefaction 

 is characteristic, as also the mode of liquefaction and fluorescence. 



On agar, too, according to Mace, the growths are quite similar, 

 while the very marked aerobian character and rapid growth are also 

 alike. 



In short, we find no important differences between the descrip- 

 tions, and therefore regard this form as identical with Flugge's B. 

 fluorescens liquefaciens. 



B. fluorescens liquefaciens minutissimus (Unna), whether a good 

 species or not, presents sufficient differences to separate it from ours. 

 Apart from its habitat, the feeble fluorescence and capacity for grow- 

 ing anaerobically would seem to separate it. 



B. fluorescens nivalis (Schmolck) is a form found in the glacier 

 waters of Norway, and reminds one forcibly of B. fluorescens lique- 

 faciens. The information to hand is too meagre to enable us to 

 decide. 



B. viscosus (Frankland) is possibly eliminated by the characters of 

 the colonies, if the author's description of the radiating hair-like 

 marginal growths is characteristic. Nor does the size quite agree, 

 though the discrepancies could hardly be insisted upon. In other 

 * See our First Eeport, Appendix B, for literature concerning these forms. 



