SUBFAMILIES AND GENERA OF COCCACEvE 99 



while only 10, or 6 per cent, were Gram-negative on both 

 trials. In both sugar broths the activity of these forms 

 was considerable, tho less than that of the strepto- 

 cocci. In dextrose the average acidity was .007 normal; 

 in lactose .004 normal. The actual distribution of the 

 cultures in regard to dextrose fermentation is indicated 

 in Figure II. The mode is there seen to come between 

 .005 and .009 normal; and it is interesting to note the 

 same tendency to fall off very gradually toward the higher 

 acidities, which was noticed among the streptococci. 

 Forty strains, or 22 per cent, of the orange cocci grew 

 distinctly better at 37 degrees than at 20 degrees, a higher 

 figure than appeared in other genera. In regard to 

 chromogenic power, however, a very characteristic rela- 

 tion was apparent. One hundred and twenty-six cultures, 

 or 70 per cent, showed better color production at 20 

 degrees than at 37 degrees. In regard to gelatin lique- 

 faction, it appeared that 54 cultures, or 30 per cent, failed 

 to exert any action in the 30 days' time for which 

 this property was observed. The extent of the effect 

 produced by the cultures which did liquefy was very 

 notable. 



On the average the depth of liquefaction produced 

 after 30 days was 2.2 centimeters, nearly double the value 

 observed for any other genus; and the curve of distribu- 

 tion for this character in Figure III makes it clear that the 

 aurococci which do liquefy exert a much more vigorous 

 action than is characteristic of any of the other genera. 



