SUBFAMILIES AND GENERA OF COCCACE^E 77 



earth, and air. On the whole, however, the average 

 characters of the two groups are quite distinct. 



In almost every point tested the group of 229 cocci 

 from the body differed in its average characters from the 

 group of 271 cocci isolated from other sources. In the 

 first group 11 per cent were uniformly Gram-negative, 

 29 per cent variable, and 60 per cent uniformly Gram- 

 positive; in the second group 44 per cent were uni- 

 formly Gram-negative, 29 per cent variable, and 27 

 per cent uniformly Gram-positive. Of the parasitic 

 cultures, 14 per cent formed a faint or meager growth 

 on agar, 53 per cent a good growth, and 33 per cent 

 an abundant or very heavy growth; of the saprophytic 

 forms only 3 per cent formed a faint or meager growth, 

 35 per cent a good growth, and 64 per cent an abundant 

 or very heavy growth. Of the parasitic cultures, only 

 28 per cent produced an alkalin or faintly acid reaction 

 (.003 normal) in dextrose broth, 44 per cent produced 

 an acidity between .003 and .007 normal, and 28 per cent 

 an acidity of .007 normal or over; among the saprophytes 

 58 per cent produced a reaction, alkalin or less than 

 .003 normal, and 20 per cent an acidity between .003 and 

 .007 normal. For lactose broth the corresponding figures 

 were 34 per cent, 34 per cent, and 32 per cent for the 

 parasites, against 65, 22, and 13 per cent for the sapro- 

 phytes. In nitrate reduction there was no well-marked 

 difference between the cocci from the body and from 

 other sources. Certain generic differences existed in 



