502 MICROORGANISMS IN WATER 



MICROCOCCUS FLAVUS DESIDENS 



| LIQUEFIES GELATINE j 



Authority. Fliigge, Die Mikroorganismcn, 1886, p. 177. 



Where Found. In air and water. 



Microscopic Appearance. Small cocci arranged chiefly as diplococci, but 

 also in a triangular form, and in short chains. Not motile. 



Cultures. 



GELATINE PLATES. In two days the colonies are visible as small white 

 yellowish dots. Under a low power they are oval and often have a lobular 

 projection on one side, yellowish brown in colour, and finely granular. The 

 surface colonies have a lighter zone near the periphery. After four days the 

 depth colonies have hardly changed, but those on the surface are from 5 to 10 mm. 

 large, and are circular and lobular, and of a pale yellow or brownish colour. 

 They form a smooth slimy expansion, but neither rise above the surface nor 

 sink much below it ; later, however, the colony slowly sinks, and becomes sur- 

 rounded by a very flat circular depression. 



GELATINE TUBES. Produces a confluent porcelain-white growth in the depth, 

 and a yellowish brown slimy expansion on the surface, which, however, does 

 not reach the walls of the tube. After eight days the gelatine below is so 

 softened that it liquefies, forming a thick fluid, the surface gradually sinking to 

 the bottom. 



POTATOES. Forms a yellowish brown, thick and slimy expansion, with an 

 irregular periphery. 



MICROCOCCUS FLAVUS TARDIGRADUS 



Authority. Fliigge, Die Mikroorganismen, 1886, p. 175. 



Where Found. In air and water. 



Microscopic Appearance. Large round cocci, exhibiting sometimes charac- 

 teristic dark poles. It is arranged chiefly in groups. 



Cultures. 



GELATINE PLATES. It grows extremely slowly. The depth colonies are 

 dark chrome yellow, and either round or oval in shape. The surface colonies 

 have a smooth sealing-wax-like surface, and project slightly above the level of 

 the gelatine. Under a low power the depth colonies are circular and smooth- 

 rimmed, and of a uniform dark olive-green colour ; the surface colonies towards 

 the periphery are lighter in colour, being more of a greyish yellow tone. No 

 liquefaction takes place. 



GELATINE TUBES. In six to eight days a number of isolated round yellow 

 colonies become visible along the path of the needle in the depth. 



