BACTERIA CAUSING SPECIFIC CHANGES 223 



fermentation. When added afterwards no injurious actions were 

 observed. The ropiness in the beer is due to two mucilaginous 

 substances produced by this organism ; one contains nitrogen and is 

 insoluble, while the other contains no nitrogen and is soluble in water. 



BACILLUS VISCOSUS SACCHARI (KRAMER). 



Found in slimy solutions of sugar. 



Microscopical Appearances. Small, non-motile rods, forming 

 threads but no spores. 



Biological Characters. Optimum temperature, 22 C. 



Stab Cultures in cane sugar gelatine liquefy quickly, an adherent 

 sediment being deposited. 



Sugar solutions containing besides the necessary nitrogenous sub- 

 stances for the growth of the bacteria, are changed into slime. 



BACILLUS VISCOSUS VINI (KRUMER). 



Found in slimy wine. 



Microscopical Appearances. Non-motile bacteria of various 

 lengths, forming threads. 



Biological Characters. Strongly anaerobic ; optimum tempera- 

 ture, 18 C. Develops only on wine and -glucose solutions. Wine is 

 fermented in one to two months, a thick slime being formed. 



' LEUCONOSTOC MESENTEROIDES (CIENKOWSKI). 



(Froschlaich pilz. Pilz der Dextrangarimg. Frog spawn fungus.) 



Found on beetroot juice and molasses of sugar factories, where it 

 develops in large gelatinous masses, resembling frog spawn. It is 

 also found on raw or cooked carrots and sugar beets. 



Microscopical Appearances. It forms chains of spherical or oval 

 cocci from 1*8 to 2 p in diameter, enclosed within a thick, tough, 

 membranous envelope. Finally, owing to the anastomoses of numerous 

 chains they appear as large, compact, gelatinous, zooglceic masses. 



Staining Reactions. The cover-glass specimen is first stained with 

 dahlia violet, which stains the cocci, and then immersed in an aqueous 

 solution of rosolic acid, which stains the gelatinous envelope a rose-red 

 colour. 



Biological Characters. It is a facultative anaerobe ; optimum 

 temperature, 30 to 37 C. It is very difficult to obtain in pure cultures, 



