NON-PATHOGENIC MICROCOCCI. 601 



183. MICROCOCCTJS VIOLACEUS (Cohn). 



Found in water. 



Morphology. Elliptical cocci, frequently united in chains. 



Biological Characters. An aerobic, non -liquefy ing, chromogenic mi- 

 crococcus. Grows in the usual culture media at the room temperature. 

 Upon gelatin plates forms superficial colonies of hemispherical form and 

 violet color. In gelatin stick cultures scanty growth along the line of 

 puncture, and upon the surface a hemispherical mass of violet-blue color. 

 Upon agar a violet -blue layer. Upon potato a violet-colored streak is 

 formed along the impfstrich. 



184. STAPHYLOCOCCUS VIRIDIS FLAVESCENS (Guttmann). 



Found in the vesicles of varicella. 



Morphology. Micrococci of irregular dimensions, solitary, in pairs, or 

 in irregular groups; does not differ in morphology from Staphylococcus 

 pyogenes aureus. 



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

 crococcus. Grows in the usual culture media at the room temperature. 

 Upon gelatin plates, at the end of two days, small, greenish-yellow colo- 

 nies become visible ; under a low power these are seen to be spherical and 

 slightly granular upon the surface less so at a later date. In gelatin stick 

 cultures growth occurs both upon the surface and along the line of punc- 

 ture, of a grayish-yellow color. Upon agar, at the end of twenty- four 

 hours at 37 C., a greenish-yellow growth occurs along the line of puncture. 

 An abundant development occurs upon potato in twenty-four hours at 

 37 C. 



185. MICROCOCCUS OCHROLEUCUS (Prove). 



Found in urine of man. 



Morphology. Micrococci, from 0.5 to 0.8 /* in diameter, solitary, in 

 pairs, or in short chains. 



Biological Characters. An aerobic, non- liquefy ing, chromogenic micro- 

 coccus. The pigment is soluble in alcohol, insoluble in water, and is decol- 

 orized by acids. Grows in the usual culture media at the room temperature. 

 Upon gelatin plates, at the end of twenty-four hours, small, colorless colo- 

 nies are developed, surrounded by a somewhat elevated and wavy border ; 

 later branching offshoots are given off from the margin and the centre ac- 

 quires a sulphur-yellow color. In gelatin stick cultures a thin, colorless, 

 superficial layer is quickly developed ; this in three or four days acquires a 

 sulphur-yellow color. The growth upon potato is scanty and is scarcely 

 visible before the fifth day. Old gelatin cultures give off a peculiar odor. 



186. MICROCOCCUS ACIDI LACTICI LIQUEFACIENS (Kreuger). 



Found in " cheesy butter." 



Morphology. Oval cocci, from 1 to 1.5 ft in diameter, frequently associ- 

 ated in pairs or in tetrads. 



Biological Characters. An aerobic smd facultative anaerobic, liquefy- 

 ing micrococcus. Grows best at the room temperature. Upon gelatin 

 plates small, white colonies are developed at the end of three days, which 

 under the microscope are seen to have deeply cleft margins ; the gelatin 

 about the colonies is gradually liquefied. In gelatin stick cultures a white, 

 granular growth occurs along the line of puncture, and a funnel-shaped 

 liquefaction of the gelatin occurs by the third day ; liquefaction progresses 

 rapidly, and a dirty-white, slightly wrinkled layer forms upon the surface, 

 while the gelatin below is clouded. In milk coagulation occurs in three 

 days at 20 to 25 C., and lactic acid is formed; a clear layer of serum is 

 seen above the homogeneous coagulated mass of casein, which is not subse- 

 quently peptonized. 



