222 CLASSIFICATION OF THE MICRO-ORGANISMS. 



extend in a horizontal direction, so that the line has a 

 pinniform appearance. At the same time a funnel- 

 shaped area of liquefaction forms at the upper part, but 

 this is very pointed and spreads relatively slowly. 



Micrococcus flavus desidens. 



Yellow Small cocci for the most part arranged as diplococci, 



BUCTOOOOCTLB, hut also in triangles and short chains. After two days 

 the colonies on nutrient jelly present the appearance of 

 whitish yellow points, which, under a low power, appear 

 as oval plates often projecting on one side, yellowish 

 brown, finely granular ; those which lie superficially have 

 a lighter zone towards the margin. After four days the 

 deeply lying colonies have undergone but little alteration, 

 they have only become more distinct. The superficial 

 ones are now 5 10 mm. in size, but present a round 

 form with various projections and a dull yellow colour 

 passing into brown; they form a smooth mucous 

 layer on the gelatine, and they neither project above it 

 nor lie markedly below the surface. It is only on 

 touching it that it becomes evident that the gelatine is 

 softened and has become pulpy in the neighbourhood of 

 the colony; after two days more this also becomes evident 

 by a moderate sinking in of the colony, which is then 

 surrounded by a very flat depressed ring 2 4 mm. in 

 breadth (hence the name desidens = slowly sinking in). 

 In tubes a confluent mass of porcellanous white appear- 

 ance is formed in the depth of the puncture canal ; on 

 the surface a yellowish brown slimy deposit, which does 

 not however reach to the walls of the glass. After eight 

 days the gelatine below the deposit is so far softened 

 that a cylinder filled with thick fluid has been formed 

 3 4 mm. in height, and of the diameter of the super- 

 ficial deposit, to the bottom of which the latter then 

 gradually sinks down. Repeatedly observed as an 

 accidental contamination on plates. 



Micrococcus versicolor. 

 Versicoloured Small cocci arranged in pairs or in masses. They 



micrococcus. 



