FAMILY MICKOCOCCACEAE 



237 



II. Pink or red pigment on agar media. 



A. Gelatin liquefied, slowly. Produces rose-colored pigment. 



13. Micrococcus roseus. 



B. Gelatin not liquefied. 



1. Non-motile. 



a. Produces cinnabar-colored pigment on gelatin. 



14. Micrococcus cinnabareus. 



aa. Produces light, flesh-colored pigment on agar slant. Ferments 

 glycerol and mannitol. 



15. Micrococcus rubens. 



aaa. Produces brick-colored pigment on agar slant. Does not ferment 

 glycerol and mannitol. 



16. Micrococcus rhodochrous. 



2. Motile. Produces red pigment. 



17. Micrococcus agilis. 

 2. Anaerobic species. 



I. Forms gas from nitrogenous media. 



A. Acid from glucose. 



18. Micrococcus aerogenes. 



B. No acid from glucose. 



1. No blackening of colonies in deep agar. 



19. Micrococcus asaccharolyiicus. 



2. Hj'drogen sulfide formed. Deep agar colonies become black. 



20. Micrococcus niger. 

 II. No gas formed from nitrogenous media. 



A. Acid from glucose. 



1. Acid from lactose. 



21. Micrococcus grigoroffi. 



2. No acid from lactose. 



22. Micrococcus anaerobius. 



1. Micrococcus luteus (Schroeter) 

 Cohu. {Bactcridium lutcum Schroeter, 

 Beitr. z. Biol. d. Pflan., /, Heft 2, 1872, 

 119; Cohn, ibid., 153.) From Latin, 

 luicus golden-yellow. 



Spheres: 1.0 to 1.2 microns, occurring 

 in pairs and fours. Non-motile. Gram- 

 positive. 



Gelatin colonies: Yellowish-white to 

 yellow, raised, with undulate margin. 



Gelatin stab: No liquefaction. 



Agar colonies : Small, yellowish, glisten- 

 ing, raised. 



Agar slant: Citron-yellow, smooth. 



Broth : Clear, with yellowish sediment. 



Litmus milk: Usually slighth- acid, 

 not coagulated. 



Potato: Thin, glistening, citron-yellow 

 growth. 



Indole not formed. 



Nitrites not produced from nitrates. 



Acid from glucose, sucrose and man- 

 nitol. No acid from lactose. 



Starch not hydrolyzed. 



Ammonia produced from peptone. 



Utilizes NH4H2 PO4 as a source of 

 nitrogen. 



Saprophytic. 



Aerobic. 



Optimum temperature 25°C. 



Source : Isolated by Schroeter from 

 dust contaminations on cooked potato. 



Habitat : Found in skim milk and dair}^ 

 products, and on dust particles. 



2. Micrococcus ureae Cohn. (Cohn, 

 Beitr. z. Biol. d. Pflanzen, 1, Heft 2, 

 1872, 158; not Micrococcus ureae Fliigge, 

 Die Mikroorganismen, 2 Aufl., 1886, 

 169; Merisla ureae Prazmowski, Biol. 

 Cent., 8, 1888, 301; Streptococcus ureae 

 Trevisan, I generi e le specie delle Bat- 



