598 NON-PATHOGENIC MICROCOCCI. 



172. MICROCOCCUS CERASINUS SICCUS (List). 



Found in water. 



Morphology. Micrococci, from 0.25 to 0.32 /* in diameter, solitary or in 

 pairs. 



Biological Characters. An aerobic, non-liquefying, chromogenic mi- 

 crococcus. Grows best at 37 C. Does not grow well in nutrient gelatin. 

 Upon the surface of agar a dry, cherry-red layer is quickly developed. 

 Upon potato the surface is quickly covered with a cherry-red layer. The 

 pigment is not soluble in water, alcohol, or ether, and is not changed by 

 acids or alkalies. 



173. MICROCOCCUS VERSICOLOR (Fliigge). 



Found in water. 



Morphology. Micrococci, in pairs or in irregular groups. 



Biological Characters. Anaerobic, non-liquefying, chromogenic micro- 

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

 gelatin plates the deep colonies are at first white points; later yellow, 

 opaque, finely granular spheres. The superficial colonies are irregular in 

 outline, slimy, and have a pear]y lustre; they may attain a diameter of two 

 to ten millimetres. In gelatin stick cultures small, spherical, yellow colonies 

 develop along the line of puncture, and a layer with irregular, "gnawed " 

 margins and a pearly lustre upon the surface. Upon agar a slimy, opaque 

 layer of a yellowish-brown color. Upon potato a slimy layer is quickly de- 

 veloped. 



174. MICROCOCCUS OF DANTEC. 



Obtained by Dantec (1891) from salted codfish which had undei'gone 

 changes characterized by a red color and an offensive odor. 



Morphology. Micrococci, from three to five n in diameter, often marked 

 by a line of commencing binary division. 



Biological Characters. An aerobic, non-liquefying, chromogenic micro- 

 coccus. Forms a red pigment. In gelatin plates small, disc-shaped colo- 

 nies of a red color are slowly developed ; these rarely measure more than a 

 millimetre in diameter. In gelatin stick cultures development is slow ; 

 along the line of puncture the growth has a yellowish color ; on the surface 

 it is of a pale-red, and later of deeper-red color. Upon agar the development 

 is more rapid than upon gelatin. It grows upon dried codfish without pro- 

 duction of pigment, except when it is associated with other microorganisms 

 especially a liquefying coccus which is often found with it. 



Not pathogenic. 



175. MICROCOCCUS CARNEUS (Zimmermann). 



Found in water. 



Morphology. Micrococci, having a diameter of about 0.8 y, united in 

 irregular, grape-like masses. 



Biological Characters. An aerobic, non-liquefying, chromogenic mi- 

 crococcus. Grows best at the room temperature ; very scanty develop- 

 ment at 30 to 33 C. Upon gelatin plates the deep colonies are small, 

 spherical, and grayish-white in color. Superficial colonies are but slightly 

 elevated, circular in outline, and of a grayish-red to pale-red color ; under 

 the microscope they are seen as circular discs with a more opaque, reddish- 

 gray centre surrounded by a somewhat more transparent zone, and this by 

 a second, still paler zone ; in older cultures the distinct zones are no longer 

 to be distinguished, but the reddish-brown color fades out from the centre 

 towards the margin of the colonies. In gelatin stick cultures, at the end of 

 five days, a thin, circular, pale-pink layer, with irregular outlines and about 



