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) Flugge 



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



Zoogalactina immetropa Sette : Mem. Venezia, 1824, 51. 



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



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



B. prodigiosus Flugge : 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. 

 1 Agar slant. Growth whitish, becoming reddish. 



Gelatin stab. Liquefaction saccate ; sediment reddish. 

 v Milk. Coagulated, acid, jteptonized, 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 //,. Facultative anaerobic, btft 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. 



