GENERIC CHARACTERS IN THE COCCACEAE 



193 



gens show maxima under the "good" growth, almost all the "very 

 abundant" growths belonging to the former class. The red forms 

 are almost all of one type the "abundant." 



TABLE 36. 

 CORRELATION BETWEEN CHROMOGENESIS AND DEXTROSE FERMENTATION. 



TABLE 37. 

 CORRELATION BETWEEN CHROMOGENESIS AND LACTOSE FERMENTATION. 



The correlations between chromogenesis and the fermentation 

 of the sugars are singularly perfect. The white forms in each case 

 show two maxima, one corresponding to the true white chromo- 

 gens, the second, at a higher acidity, to the colorless streptococci. 

 The latter include a majority of the strongest acid-producers in 

 each case. The other types show for each sugar a regular and char- 

 acteristic curve, the elements from which the complex curve in 

 Fig. 2 is made. The yellow forms show for each sugar a mode at 

 the neutral point. The orange chromogens, on the other hand, 

 are most abundant at an intermediate grade of acidity, most of 

 them producing 0.3-0.6 per cent acidity in dextrose broth, and 

 0.1-0.4 per cent in lactose broth. The red forms show the same 

 relation as the orange forms toward dextrose, while in lactose broth 

 they resemble the yellow chromogens, producing in most cases no 

 change of reaction. 



TABLE 38. 

 CORRELATION BETWEEN CHROMOGENESIS AND NITRATE REDUCTION. 



