82 



RELATIONSHIPS OF THE COCCACEjE 



The study of other characters correlated with pigment 

 production strengthened the conclusion that the color 

 types of the cocci correspond to four natural groups. In 

 cell grouping, the property of packet formation occurred 

 in about half the yellow and red chromogens studied; it 

 was observed only rarely and doubtfully among the white 

 and orange forms. The reaction to the Gram stain, as 

 shown in the table below, exhibits a similar sharply 

 marked difference. 



CORRELATION BETWEEN CHROMOGENESIS AND GRAM STAIN. 

 Number of cultures in each class. 



Among the whites and oranges (the parasitic forms) 

 positive Gram reactions predominate, and negative ones 

 are rare. Among the saprophytic yellows and reds, 

 conditions are symmetrically reversed. 



CORRELATION BETWEEN CHROMOGENESIS 

 GROWTH. 

 Number of cultures in each class. 



AND SURFACE 



Surface Growth. 



Very faint . . 

 Meager. . . . 



Good 



Abundant . . 

 Very heavy . 



White. 



14 

 3 

 7 



13 

 3 



Yellow. 



100 

 95 



5° 



Orange. 



2 



12 



107 



58 



Red. 



o 

 o 

 1 

 24 

 o 



