128 BACTERIOLOGY 



Gelatin stab. No growth in depth ; on the surface, growth flat, spreading 



irregular. 

 Glucose yeast water. Turbid ; on the surface a very thin pellicle, which is 



slimy and easily broken, with a tendency to rise up on the walls of the 



tube. In yeast water, with 5 per cent of alcohol, a strong acetic acid 



production. 

 Habitat. Isolated from sour dough. 



19. Bact. viscosum van Laer 



Bact. viscosum-cerevisa van Laer : Acad. royale de Belgique, 1889, 36. 



Morphology. Bacteria 0.8 : 1.6-2.4 /u,. 



Gelatin colonies. Entire erose, brownish. 



Potato. Growth of white, watery, doughy colonies, which smell like foul fish. 



Beer-wort. Rendered viscous ; CO 2 evolved. 



Milk and glucose bouillon. Rendered slimy, with gas production. 



Habitat. Isolated from beer, yeast, and bread ; causes a viscous fermentation. 



BACT. AEROGENES GROUP 



20. Bact. aerogenes Escherich 



~ Bact. lactis-aerogenes Escherich: Fortschritte Medizin, 1885, No. 16-17. 

 Bact. aceticum Babinsky: Zeitsch. f. phys. Chem., XII, 1888, 434. 

 Bacillus aerogenes Kruse : Fliigge, Die Mikroorganismen, 1896, 340. 



Morphology. Bacilli 0.5-1.0: 1.0-2.0 /n. 



Gelatin colonies. Deep: round, granular, grayish brown. Surface: porce- 

 lain-white, round, convex ; microscopically, yellowish, granular, darker in 

 the centre. 



Gelatin stab. In depth, a good growth ; on the surface, a round, convex 

 growth. 



Bouillon'. Turbid ; a slight membrane. 



Agar slant. Growth rather opaque, porcelain-white. 



Potato. Growth moist, yellowish white, with development of gas and a cheesy 

 odor. 



Milk. Coagulated ; strongly acid. Indol negative. 



Pathogenesis. Variable ; for the smaller animals, usually pathogenic only in 

 large doses (toxaemia). 



Habitat. Milk, faeces, air, water, etc. 



