SAPROPHYTIC MICKOCOCCI. 223 



form white points on gelatine plates after 24 hours; 

 after two clays, yellow colonies, spherical when lying 

 deeply, up to 1 mm. in size, circular under a low power, 

 with sharp contours of yellowish green colour, opaque, 

 finely granular. The colonies which lie superficially 

 form flat deposits 2 6 mm. in size, increasing even to 

 10 mm. after four or five days, of irregular form, often 

 almost quadrilateral, as a rule approaching this form 

 very closely, and with an irregular outline. The deposit 

 is gelatinous, glistening at the surface, and yellowish 

 green, but according to the illumination there is a 

 greenish arid bluish shimmer like mother of pearl. In 

 the middle of the deposit there is often a somewhat 

 projecting knob, the remains of the deeper part of the 

 colony. Along an inoculation puncture small spherical 

 colonies of a yellow colour are formed ; on the surface 

 a deposit with irregular margins as if eaten out and 

 changing colour like mother of pearl. Common. 



Micrococcus viticulosus.* 



Micrococci with a very peculiar mode of growth Micrococcus 

 observed by Katz in the Hygienic Laboratory at Gottin- 

 gen. They are somewhat oval, and measure about 1*2 p. 

 in the largest and 1 /*. in the smallest diameters ; they 

 always form thick zooglsea masses, but without parti- 

 cularly marked development of gelatinous material. On 

 gelatine plates their growth is quite different according as 

 the colonies develop in the substance of the material or 

 on the surface. In the first case fine hair-like tendrils 

 develop from a centre, which soon however becomes 

 scarcely noticeable, and these- form an extremely fine 

 and delicate meshwork and extend widely. Under the 

 microscope we see that these processes do not have 

 smooth contours, but are markedly bulged out ; they 

 consist of numerous spherical large or small zooglsea 

 masses arranged in rows like a string of beads. If the 

 threads reach the surface, or if from the first the colonies 

 lie near the surface, a thin deposit is formed of a muddy 

 white appearance and gelatinous consistence, and spreads 



