594 NON-PATHOGENIC MICROCOCCI. 



160. MICROCOCCUS FLAVUS DESIDENS (Fltigge). 



Found in air and water. 



Morphology. Small micrococci, usually in pairs, but sometimes seen in 

 groups of three or in short chains. 



Biological Characters. An aerobic, liquefying, chromogenic micro- 

 coccus. Grows slowly in the usual culture media at the room temperature. 

 Upon gelatin plates the deep colonies appear as white or yellow points; 

 under a low power they are seen as oval, yellowish-brown, finely granular 

 discs. The superficial colonies are circular, with irregular margins, and are 

 not elevated above the level of the gelatin ; by the fourth day they may 

 attain a diameter of five to ten millimetres ; they have a brownish-yellow 

 color ; the gelatin is gradually liquefied, and the colony which sinks below 

 the surface is surrounded by a ring of liquefied gelatin from one to four 

 millimetres broad. In gelatin stick cultures a slimy, yellowish- brown layer 

 of limited extent is formed upon the surface, and a confluent, porcelain- 

 white mass along the line of puncture ; at the end of eight days liquefac- 

 tion has occurred under the superficial layer to a depth of three to four mil- 

 limetres, forming a cylinder filled with a thick fluid, to the bottom of which 

 the surface growth gradually sinks. Upon potato a slimy, yellowish-brown 

 layer with irregular outlines is slowly developed. 



161. MICROCOCCUS AGILIS (Ali-Cohen). 



Found in water. 



Morphology. Micrococci, one n in diameter, usually in pairs, oc- 

 casionally in tetrads or in chains ; have extremely slender flagella, which 

 are four to five IJL in length. 



Biological Characters. An aerobic, liquefying (very slowly), motile, 

 chromogenic micrococcus. Grows at the room temperature in the usual cul- 

 ture media not in the incubator at 37 C. This micrococcus is distinguished 

 by its active movements and by the presence of a longflagellum. which may 

 be demonstrated by Loffler's method of staining. In gelatin stick cultures 

 growth occurs along the line of inoculation, and liquefaction commences at 

 the end of three to four weeks ; sometimes only a dry, funnel-shaped cavity 

 is formed. Upon agar and upon potato a pink layer is slowly developed. 



162. MICROCOCCUS FUSCUS (Maschek). 



Found in water. 



Morphology. Micrococci, which are often elliptical, or even in the form 

 of short rods (bacilli ?). 



Biological Characters. An aerobic, liquefying, chromogenic micrococ- 

 cus. Grows in the usual culture media at the room temperature. Upon 

 gelatin plates forms spherical colonies which under a low power present the 

 appearance of being finely cleft and vary in color from pale-brown to black; 

 liquefaction quickly occurs. In gelatin stick cultures but scanty growth 

 occurs along the line of puncture ; upon the surface a sepia-brown layer is 

 formed and the gelatin is quickly liquefied. Gelatin cultures have a strong 

 putrefactive odor. Upon potato a slimy, brown layer is formed, which be- 

 comes almost black. 



163. DIPLOCOCCUS CITREUS CONGLOMERATUS (Bumm). 



Obtained from gonorrhceal pus and from the air in dust. 



Morphology. Diplococci, consisting of two hemispherical elements sepa- 

 rated by a narrow cleft, and closely resembling the Micrococcus gonorrhoeas ; 

 about 1.5 jj. in diameter; frequently in tetrads, usually united in conglomerate 

 masses. 



Biological Characters. An aerobic and facultative anaerobic, liquefy- 



