406 CLINICAL BACTERIOLOGY. 



(b) Nonchromogenic. 



27. Micrococcus Candicans. This is a round coccus of .mod- 

 erate size. Its most distinctive feature is its growth in gelatin 

 stab-cultures, in which a nail-shaped growth appears, with a 

 porcelain-white, glistening head. 



28. Micrococcus Concentricus. This is characterized by the 

 concentric extension of its colonies upon gelatin-plates and in 

 stab-culture. The colonies present from a whitish-gray to a 

 bluish-gray color, and are superficially serrated. The cocci 

 themselves are small and are arranged like grapes. 



29. -Micrococcus Rosettaceus. This is a coccus of moderate 

 size. Its growth is mainly superficial. Roset-like deposits 

 form, with irregular margins. The colonies are grayish-white 

 in color, but darker in the center, up to brown. 



jo. Micrococcus Aquatilis. The colonies are round, and 

 possess a mother-of-pearl luster. The margins appear serrated ; 

 the color is light gray. Viewed with low powers of the micro- 

 scope, the colony appears in the form of a berry. 



2. LIQUEFYING GELATIN. 



(a) Chromogenic. 



31. Micrococcus Cremoides. This is a small coccus, arranged 

 in groups, and giving rise to a cream- colored pigment. At first, 

 the colonies upon gelatin are from yellowish-white to brownish- 

 gray, granular, circular ; while later the discs appear eroded, 

 and they lie in a liquefied excavation. 



32. Sarcina Lutea (Yellow Sarcina). This coccus, strictly 

 aerobic, is arranged in so-called balls of twine. Upon gelatin- 



plates it forms rounded, slightly granular, 

 yellow colonies. In stab-cultures marked 

 superficial growth takes place. The cul- 

 tures generate a citron-yellow pigment. 

 Liquefaction occurs quite late ; then the 

 clear, liquefied gelatin overlies the citron- 

 yellow precipitate. In addition to the yel- 



Fig. 8 7 .-Sardn; X orange 



and red sarcinae, which are distinguished 

 from that described only by the difference in color. The 

 varieties of sarcinae are present in the air. 



33. Micrococcus Agilis (Ali Cohen). This actively motile 

 organism (flagella), cultivated from drinking-water, grows upon 

 all nutrient media, with the formation of a rose-red pigment. 

 It slowly liquefies gelatin. 



(b) Nonchromogenic. 



34. Micrococcus Radiatus. This is a small coccus, without 

 typical arrangement. Upon plates it forms colonies surrounded 



