184 RELATIONSHIPS OF THE COCCACE^ 



Neumann, and the M. aureus of Migula. We have given 

 it the name Aurococcus aureus, and its characters may be 

 denned as follows: 



1. Aur. aureus (Rosenbach) Winslow. A parasitic 

 coccus, living normally on the surface of the human or animal 

 body, or in diseased tissues. Occurs singly \ or in pairs, or 

 irregular groups, rarely in short chains. Generally stains 

 by Gram. Good to abundant surface growth of orange color. 

 Moderate acid production in dextrose and lactose broth. 

 Nitrates not reduced. Growth good at both 20 degrees andtf 

 degrees, but pigment production much better at 20 degrees. 

 Gelatin liquefied rapidly. 



The following names of yellow cocci listed by Migula 

 and Chester are apparently synonyms of Aur. aureus: 

 M. subflavidus, Migula; M. Beri-Beri, Pekelharing; M. 

 Biskra, Heydenreich; M. lobatus, Migula; M. cremoides 

 aureus, Dyar; M. chryseus, Frankland; M. aqueus, Migula; 

 M. argenteus, Migula; and M. madidus, Migula. 



A second group of the Aurococcus cultures, studied by 

 us, was distinguished from the Aur. aureus type by failure 

 to liquefy gelatin, no peptonizing action being observed 

 after fourteen days. Comparison of other biochemical 

 characters showed further differences; and the frequency 

 curves plotted in Fig. Ill clearly indicate that liquefying 

 and non-liquefying types, in this and other genera, con- 

 stitute distinct and separate centers of variation. The 

 organisms of the genus Aurococcus, which failed to 

 liquefy gelatin, formed little acid in lactose media and 



