222 RELATIONSHIPS OF THE COCCACEyE 



the other properties of the genus — saprophytic origin, 

 negative Gram reaction, low fermentative power, etc. — 

 formed an absolutely white growth. On the other hand, 

 there was a slight but distinctly marked type center of 

 paler yellow tint. Six of our twenty-five strains of M. 

 luteus formed a pigment which, when matched as de- 

 scribed in Chapter III, fell in the upper horizontal line 

 of the color chart (see Frontispiece). Only two fell in the 

 second line and five and seven in the third and fourth, 

 respectively. The numbers are of course too small to 

 draw conclusions from, but the contrast with the other two 

 species, each of which has a single well-marked type 

 center, is suggestive. The distribution of hues for the 

 three species of micrococci is tabulated below. 



DISTRIBUTION OF HUES AMONG THE SPECIES OF MICROCOCCI. 

 Number of Strains of Each Hue. 



* See Frontispiece. 



In view of the small number of strains observed we should 

 not have attached importance to the light center among the 

 non-liquefying forms, except for the evidence from other 

 observers as to the common occurrence of similar organisms 

 in nature. In the light, however, of Gordon's work, and 

 of the numerous descriptions of white non-liquefying sapro- 

 phytic species, whose names will be listed below, it seems 



