606 NON-PATHOGENIC MICROCOCCI. 



gray, rosette-like layer of irregularly circular contour develops upon the 

 surface; very scanty growth along the line of puncture. Upon aoar a 

 smooth, shining, gray layer with finely toothed margins. Upon potato a 

 yellowish-gray layer is quickly formed. 



202. MICROCOCCUS URE.E (Pasteur). 



Found in the air and in ammoniacal urine. 



Morphology. Micrococci, from 0.8 to 1 /f in diameter, solitary, in pairs, 

 in tetrads, or in short chains ; also in zoogloea masses. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying micrococcus. Grows in the usual culture media at the room tem- 

 peraturebetter at 30 to 35 C. Upon gelatin plates forms, at the end of 

 twenty-four hours, small, white, pearly, shining colonies of smooth surface 

 and sharply defined outline ; at the end of ten days these are large, flat colo- 

 nies resembling a drop of stearin. In gelatin stick cultures development oc- 

 curs along the line of puncture in form of a thin, tenacious thread. Old cul- 

 tures have a paste- like odor. 



According to Von Jaksch, a very favorable medium for the growth of this 

 micrococcus is made by adding to one litre of water, magnesia sulphate 

 one-sixteenth gramme, potassium hypophosphite one-eighth gramme, potas- 

 sium sodium tartrate five grammes, urea five grammes. In urine and solu- 

 tions containing urea carbonate of ammonia is formed during the develop- 

 ment of this micrococcus ammoniacal fermentation. 



203. MICROCOCCUS URE.E LIQUEFACIENS (Flugge). 



Found in ammoniacal urine. 



Morphology. Spherical cocci, from 1.25 to 2 n in diameter, solitary, in 

 chains of three to ten elements, or in irregular groups. 



Biological Characters. An aerobic and facultative anaerobic, liquefying 

 micrococcus. Grows in the usual culture media at the room temperature. 

 Upon gelatin plates forms, at the end of twenty-four hours, small, white, 

 punctiform colonies, which under a low power appear as well-defined, dark- 

 gray spheres; after they reach the surface of the gelatin the colonies become 

 considerably larger, have a yellowish-brown color and a central nucleus 

 consisting of the original deep colony ; the surface of the superficial colo- 

 nies is granular, the outline becomes gradually wavy ; liquefaction of the 

 gelatin around the colonies occurs gradually. In gelatin stick cultures a 

 confluent, white growth develops along the line of puncture, and liquefac- 

 tion quickly occurs and extends to the walls of the tube; finally one-half 

 or more of the gelatin is liquefied and has a whitish, clouded appearance^ 

 while a thick, yellowish- white deposit is seen at the bottom. 



204. MICROCOCCUS VITICULOSUS (Katz). 



Found in the air and in water. 



Morphology. Oval micrococci, from 1 to 1.2 n in diameter; forms thick 

 zoogloea masses. 



Biological Characters. An aerobic and facultative anaerobic, non- 

 liquefying micrococcus. Grows rapidly in the usual culture media at the 

 room temperature. Upon gelatin plates the deep colonies are seen to con- 

 sist of hair-like branches given off from a centre, and which for some dis- 

 tance form a delicate network ; under a low power these branches are seen 

 to be made up of zoogloea masses of various dimensions united in chaplets. 

 The superficial colonies extend rapidly as a thin, jelly-like, clouded white 

 layer, from which fine threads are given off into the deeper layers of the 

 gelatin. In gelatin stick cultures growth occurs along the line of puncture 

 as a delicate network of threads ; upon the surface a feathery growth occurs 

 along the line of inoculation. Upon potato a dry, dirty-white layer is. 

 quickly developed. 



