350 MICROBIOLOGY 



tion. It may be obtained from dust in the air, from water and 

 from the soil. Klein 4 describes contamination of meat and 

 fish with B. prodigiosus, which gave rise to "pink" beef and 

 fish. A thorough cleaning and disinfection of the place elimi- 

 nated the trouble. 



Morphology. B. prodigiosus appears sometimes perfectly 

 spherical, sometimes oval or elliptical, and sometimes as short 

 rods. They measure from 0.5 /x to 1.0 n or more in diameter. 

 It does not produce spores. There have been observed between 

 the living cells masses of granules of different shapes, some 

 much smaller, others much larger than the coccus, round or 

 irregular in shape, and colored a very bright red. 5 



Cultivation. It grows especially well as an aerobe, but 

 also, although more slowly, as an anaerobe. T-he most favor- 

 able temperature for its development seems to be from 23 

 to 25 C. At 35 and above, the production of pigment de- 

 creases and soon ceases. 



Agar. On slant agar the growth appears as thick bands 

 of reddish color which become blood-red as they grow older 

 and often show a metallic-like surface. The upper part of the 

 thick shiny layer, directly in contact with the air, is alone 

 highly colored. 



Gelatin. On gelatin plates it forms in 24 hours, at 20 C., 

 small rounded colonies of a grayish color. The deep colonies 

 come to the surface and have a bright color in the center. 

 Liquefaction takes place rapidly. In twelve hours, the whole 

 plate is liquefied. The liquid gelatin has a reddish color. 



Potato. Growth is abundant on this medium. There ap- 

 pears after 24 hours a whitish layer which gradually spreads 

 and forms a thick growth of a red color. The surface of the 

 growth exhibits in some places a metallic green resembling 

 that of fuchsin. 



Serum. Serum is gradually liquefied. .The growth re- 

 sembles that on agar. 



Bouillon. This medium quickly becomes turbid and takes 



4 Klein. The Jour, of Path, and Bact, Vol. II (1894) p. 214. 



5 Mace. Traite de Bacteriologie. 



