600 NON-PATHOGENIC MICROCOCCI. 



coccus. Grows in the usual culture media at the room temperature better 

 at 37 C. Upon gelatin plates forms upon the surface dirty pale-yellow or 

 cream-colored colonies, which after several days have a diameter of 0.5 to 

 0.8 centimetre and are about 0.5 millimetre thick; these have usually irre- 

 gular outlines and a moist, shining appearance. In gelatin stick cultures 

 very scanty growth occurs along the line of puncture. Upon agar a pale- 

 yellow layer is formed. Upon potato, at 37 C., an abundant growth occurs, 

 forming a yellow layer. 



180. MICROCOCCUS FERVIDOSUS (Adametz). 



Found in water. 



Morphology, Small, round cocci, 0.6 n in diameter, in pairs or in ir- 

 regular groups. 



Biological Characters. An aerobic, non-liquefying micrococcus. Grows 

 in the usual media at the room temperature. Upon gelatin plates, at the end 

 of four to five days, the deep colonies appear as white points, which under a 

 low power have a pale-yellow color and resemble dewdrops; upon the sur- 

 face transparent, yellow colonies with irregular, jagged edges are devel- 

 oped ; later these are granular in the centre and have a brownish color, 

 while the marginal zone is yellowish and slightly wrinkled. In gelatin 

 stick cultures a thin, circular layer with finely toothed margins forms upon 

 the surface, and a granular growth along the line of puncture. In glycerin- 

 gelatin numerous gas bubbles of various sizes are developed in the medium. 

 Upon agar a circular, milk-white, slimy layer is formed, which later has a 

 pearly lustre. Upon potato a dirty- white layer with irregular margins. 



181. MICROCOCCUS FLAVUS TARDIGRADUS (Fliigge). 



'Found in the air and in water. 



Morphology. Large, spherical cocci, usually associated in irregular 

 groups ; sometimes have peculiar dark poles. 



Biological Characters. An aerobic, non-liquefying, chromogenic mi- 

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

 Upon gelatin plates the deep colonies are spherical or oval, dark chrome- 

 yellow, and from 0.4 to 0.6 millimetre in diameter; under a low power 

 they appear to have a dark olive-green color. The superficial colonies are 

 from 0.5 to 1 millimetre in diameter, have a smooth, varnished-looking sur- 

 face, and are slightly elevated above the surface of the gelatin at the mid- 

 dle ; under a low power the centre is grayish-yellow and the margin paler. 

 In gelatin stick cultures, at the end of eight days, a row of small, spherical, 

 isolated yellow colonies is developed along the line of puncture. 



182. MICROCOCCUS LUTEUS (Cohn). 



Found in water. 



Morphology. Oval cocci, from 1 to 1.2 /* in diameter, associated in zo- 

 oglcea masses ; the intercellular substance is easily soluble in water. 



Biological Characters. An aerobic, non-liquefying, chromogenic mi- 

 crococcus. The yellow pigment produced is not soluble in water, ether, or 

 alcohol, and is not changed by acids or alkalies. Grows in the usual cul- 

 ture media at the room temperature. Upon gelatin plates sulphur-yellow, 

 superficial colonies are developed, which have irregular outlines and may 

 attain a diameter of 4 millimetres and a thickness of 0. 5 millimetre ; under 

 a low power they are seen to be granular. In gelatin stick cultures a yel- 

 low layer forms about the point of puncture and a granular growth along 

 the line of inoculation. Upon agar a yellow, slimy layer. Upon potato an 

 intensely yellow layer with irregular margins, which after a time has a 

 wrinkled surface. 



