82 BACTERIOLOGY 



23. M. Rheni 



Rhine Water Micrococcus Burn : Archiv f. Hygiene, XIX, 1893, 1. 



Morphology. Cocci variable 0.5-1.25 p ; scarcely ever quite round, mostly flat- 

 tened ; in tetrads. 



Gelatin Colonies. Deep colonies: Lenticular, granular near the periphery. 

 Surface colonies : In 2-3 days, white; microscopically round; border 

 slightly irregular, granular ; after 7 days still small, when they begin to 

 sink in the softened gelatin. 



Gelatin stab. In 2 days a slight depression, which later resembles an air 

 bubble, becoming in 7 days a narrow funnel, with a white granular sedi- 

 ment, and a surface scum. Liquefaction takes place slowly. 



Glycerin agar colonies. Deep colonies : Like gelatin colonies. Surface 

 colonies: In 2 days, white, glistening, slightly convex; microscopically 

 granular. Growth viscid. 



Bouillon. Turbid, not clearing ; finally a granular white sediment. 



Milk. No appreciable growth, and no coagulation. 



Glucose bouillon. No gas. 



Pathogenesis. Guinea pigs, negative. 



Habitat. Rhine water. 



Class IV. Without Pigment. Grow on Ordinary Culture Media 

 and at Room Temperatures 20 C. Gelatin not Liquefied. 



I. Gelatin colonies distinctly filamentous or arborescent. 



24. M. viticulosus Fliigge. 



25. M. stellatus Maschek. 



II. Gelatin colonies compact. 



A. Cocci in tetrads, surrounded by a capsule. 



26. M. tetragenus Koch-Gaffky. 



27. M. Mendoza (Trevisan) Mendoza. 

 D. Cocci morphologically identical with gonococcus. 



28. M. tardissimus (Trev.) Bumm. 



29. M. magnus (Rosenthal). 

 C. Cocci united in zobgloea masses. 



30. M. candidus Cohn. 



D. Cocci not as before specified, staphlococci. 

 1. Colonies concentrically zoned. 



a. Growth on gelatin dirty white, yellowish white. 



31. M. eczema. 



32. M. Sornthalii Adametz. 



