104 RELATIONSHIPS OF THE COCCACE^E 



GENUS V. ALBOCOCCUS (Winslow and Rogers). Par- 

 asites. Cells in groups and short chains (never in packet's}. 

 Generally stain by Gram. Growth on agar streak abundant, 

 and porcelain-white in color. Sugars fermented with pro- 

 duction of a moderate amount of acid. Gelatin liquefaction 

 and nitrate reduction may or may not occur. 



This genus closes the series of the Paracoccaceae. The 

 saprophytic forms, the Metacoccaceae, are distinguished 

 from all the types so far defined by their generally negative 

 Gram reaction and their low fermentative power. They 

 are grouped about two color-types, the red and the yellow, 

 which are characteristically saprophytic rather than para- 

 sitic in habit; and one of these, the red type, has special 

 peculiarities of its own. 



The first group of the Metacoccaceae includes the 

 yellow cocci. These organisms frequently show the 

 packet grouping. Two hundred and fifty-one, or over 

 half of our 500 cocci, fell in this group and packet for- 

 mation was observed in 137 cultures out of the 251. 

 The yellow type includes a large number of the forms 

 described as species in the genera Micrococcus and Sar- 

 cina. In our series the properties of the packet-formers 

 and the non-packet-formers ran almost exactly parallel; 

 and it is doubtful whether the single property of the 

 sarcina grouping is of sufficient importance to warrant 

 generic rank. The names Micrococcus and Sarcina are, 

 however, so firmly established in the literature of bacteri- 

 ology that we have hesitated to disturb them. 



