DESCRIPTION OF SPECIES 



441 



milk acid, but insufSciently to 

 curdle it unless heated. 



Aerobic. 



Non-pathogerdc. 



MICROCOCCUS ROSACBUS 

 liACTIS (Conn). 



Source and habitat — Originally ob- 

 tained from Uruguay, but also in 

 Connecticut milk. 

 MorpJwlogy — Micrococcus ; -8 a in 



diameter ; grouped in fours. 

 Staining reaction — Ordinary stains. 

 Biology: cultural characters {includ- 

 ing biochemical features). 



Bouillon — After a few days a 

 pink sediment appears. No scum. 

 Gelatine plates and tubes — Light 

 pink colonies showing nucleus, 

 pale zone around it ; centre raised, 

 edges thin. In stab-cultures slight 

 growth on surface, and along track 

 of needle, pink coloration. 



Agar plates and tubes j potato — 

 Moist, thick, pink growth. 



Milk — No curdling. Reaction 

 slightly alkaline. Slight pink tinge 

 appears after 2 weeks. Pink scum 

 and sliminess of milk occur event- 

 ually. 

 Aerobic. 

 Non-fathogenic. 



MICROCOCCUS RUBIOUS LACTIS 



(Conn). 



Source and habitat — Obtained only 

 once in milk. 



Morphology — Coccus ; I m in diameter. 



Staining reaction — Ordinary aniline 

 stains. 



Capsule J motility — Non-motile ; non- 

 staining capsule. 



Biology : cultural characters {includ- 

 ing biochemical features'). 



Gelatine plates and tubes — 

 Rapidly liquefying, with red pig- 

 ment. In tubes a narrow funnel 



is produced with red deposit. 

 Eventually whole gelatine liquefies 

 and becomes red. 



Agar plates and tubes; potato — 

 Blood-red, thick, luxuriant growth. 

 Pigment not produced at 35" C, 

 best at 23° C. 



Milk — Does not curdle milk or 

 turn it red. No change in reaction. 



A'irobic. 



Non-pathogenic. 



MICROCOCCUS VARIANS LACTIS 



(Conn). 



Source and habitat — Milk and cream ; 



found on plates exposed near cow. 



Morphology — Coccus, variable ; i /t in 



diameter. Never forms chains. 

 Staining reaction — Stains readily with 



ordinary stains. 

 Motility — Non-motile. 

 Biology : cultural characters {includ- 

 ing biochemical features). 



Bouillon — In 2 days slight 

 cloudiness, which in 6 days is very 

 marked. Yellow sediment in 4 

 weeks. 



Gelatine plates and tubes — 

 Whitish-yellow colonies pitting on 

 liquefaction, which is rapid. In 

 stab-cultures a broad shallow funnel 

 of liquefaction occurs. 



Agar plates and tubes — A dry, 

 rough, yellow growth. Colour 

 varies from white to orange. 



Potato — A dry, granular, orange- 

 yellow growth. 



Milk — Curdles at 36" in 3 days. 

 Reaction amphoteric at 20° C. ; 

 curdles in 10 days. 

 Aerobe — A facultative anaerobe. 

 Non-pathogenic. 



MICROCOCCUS VISCOSUS LACTIS 



(Conn). 



Source a/td habitat — Milk and cream. 

 Morphology — Coccus ; -9^1 in diameter; 

 in pairs or chains. 



