QUALITATIVE BACTERIOLOGICAL ANALYSIS. 75 



Micrococcus Aquatilis. 



This organism consists of very small cocci, often arranged in 

 irregular heaps. In gelatine plates the surface colonies are 

 circular, with a narrow homogeneous marginal zone and a 

 darker centre, which strongly resembles a section of a Liver 

 acinus ; the colonies in the depth, under a low power, have a 

 yellow colour and resemble a mulberry in appearance. In 

 gelatine-stab and on agar there is a white growth, which is not 

 characteristic. 



Micrococcus Luteus. 



This organism forms large elliptical cocci. In gelatine plates 

 the surface colonies are raised, sulphur-yellow in colour, and 

 have an irregular margin ; the gelatine is not liquefied. In 

 gelatine-stab and on agar and potato the same sulphur-yellow 

 growth appears. 



The Micrococcus aurantiacus closely resembles the M. luteus, 

 but the colour produced is orange-yellow instead of sulphur- 

 yellow. 



Micrococcus Fervidosus. 



Found by Adametz in water. It is a small round coccus, 

 which occurs as diplococci and also in small groups. In gelatine 

 plates the colonies in the depth appear after four or five days 

 as small white dots. Under a low power they are faint yellow 

 in colour and smooth rimmed. The surface colonies are trans- 

 parent and yellow, with a serrated edge and numerous lobular 

 projections; the gelatine is not liquefied. In gelatine-stab it 

 forms a thin finely-serrated surface expansion ; along the stab 

 there is a granular growth. In cane-grape and milk-sugar it 

 develops slowly. On agar it forms a milk-white slimy expansion. 

 On potato it forms a dirty white growth. 



Micrococcus Flavus Tardigradus. 



Described by Flugge. It forms large round cocci, which at 

 times exhibit characteristic dark poles ; usually arranged in 

 heaps. It grows extremely slowly ; after six days the deep 

 colonies are still very small, round or oval in shape and dark 

 chrome-yellow in colour. The surface colonies have a smooth 



