3 1 6 BACTERIOLOGY. 



thread-forms. Spore-formation present. In nutrient 

 gelatine they form dot-like colonies of greenish- 

 yellow colour, which liquefy the gelatine. In test- 

 tubes a somewhat funnel-shaped liquefaction results. 

 On potatoes they develop a yellowish layer. Power- 

 fully aerobic. Found as a contamination. 



Bacillus mesentericus fuscus, Fliigge. 

 Small, short, actively-motile bacilli, often linked in 

 twos and fours. Spore-formation present. They 

 form white colonies on plate-cultivation, which later 

 stream out in rays at the periphery, and liquefy the 

 gelatine. In test-tube cultivations a funnel-shaped 

 turbidity is produced, and then a stratum of 

 liquefied gelatine with subsiding flocculi. On 

 potatoes they develop a smooth yellowish layer, 

 which soon becomes folded and wrinkled, forming 

 a delicate veil over the nutrient surface. They 

 occur on unsterilised potatoes. 



Bacillus mesentericus vulgatus, Fliigge 

 (Potato bacillus). Rods, longer and thicker than the 

 above, and sometimes thread - form s ; spore-for- 

 mation present. The colonies, at first somewhat 

 transparent, have later an opaque centre, and 

 liquefy the gelatine. In test-tubes of nutrient 

 gelatine a funnel-shaped turbidity results, and 

 then an upper-stratum is completely liquefied, 

 while a skin floats on the surface, and flocculent 

 masses subside to the bottom of the liquid layer. 

 They occur on potatoes. 



