258 BACTERIOLOGY 



Gelatin stab. Liquefaction infundibuliform. No pigment in depth or at 37 . 

 Agar slant and potato. Growth raspberry red. 

 Habitat. Water. 



142. B. prodigiosus (Ehrenberg) Flligge 



Serratia marcrescens Bizio : Folent porporp. in Bilb. Ital., XXX, 1823, 288. 



Zaogalactina immetropa Setter Mem. Venezia, 1824, 51. 



Monas prodigiosa Ehrenberg: Monatsber. K. Akad., Berlin, 1848. 



M. prodigiosus Conn : Beitrage Biol., I, 1872, 153. 



B. prodigiosus Fliigge: Die Mikroorganismen, 1886. 



Morphology. Bacilli 0.5 : 0.5-1.0; coccoid forms; filaments in acid bouillon. 

 Optimum temperature 22-25. No pigment at 38-39. Flagella peri- 

 trichic, 6-8. 



Gelatin colonies. Deep colonies round oval, entire, reddish-brownish ; trans- 

 lucent borders. Deep colonies irregular, with rough contours ; granular, 

 gray-brown, liquefied, when the red color of the colony appears. 



Agar slant. Growth whitish, becoming reddish. 



Gelatin stab. Liquefaction saccate ; sediment reddish. 



Milk. Coagulated, acid, peptonized, yellowish-reddish. 



Potato. Growth rose-red, moist, becoming dark red to purple-red ; odor of 

 trimethylamine. 



Bouillon. Turbid, reddish, with a slight pellicle. Pigment soluble in alcohol 

 and ether. The solution becomes orange-yellow on the addition of 

 alkalies and violet-red with acids. 



Glucose bouillon. Gas production variable ; no acid. H 2 S negative. Indol 

 slight. 



Pathogenesis. Scarcely pathogenic, toxic in very large doses. 



Habitat. Commonly present on articles of food, particularly starchy materials ; 

 also meat, water, etc. 



143. B. fuchsinus B6khout-de Vries 



Centralblatt f. Bakteriol., 2te Abt., IV, 1898, 497. 

 Morphology. Bacilli 0.5-0.7: 1 1 .5 ft. Facultative anaerobic, but oxygen 



necessary for the formation of pigment. Optimum temperature 22-25. 



No pigment at 36 . 

 Agar colonies. White, becoming reddish, thin, metallic, sharp. 

 Gelatin stab. In depth, growth, but no pigment ; on the surface, growth 



bright red. 

 Agar slant. Growth carmine-red, with a metallic shimmer. Grow best on 



slightly alkaline or neutral media. 



