THE GENUS AUROCOCCUS 179 



these genera are not comparable to those of the higher 

 plants. Intermediate forms exist which connect the two 

 types. As actually found in nature, however, the para- 

 sitic cocci group themselves about these two main centers, 

 and as a matter of practical expedience it is convenient 

 to give them names. 



These various considerations have led us to the follow- 

 ing definition of the genus Aurococcus: 



Genus Aurococcus (Winslow and Rogers). Para- 

 sites. Cells in groups and short chains, very rarely in 

 packets. Generally stain by Gram. On agar streak good 

 growth, of orange color. Sugars fermented with formation 

 of moderate amount of acid. Gelatin often liquefied very 

 actively. May or may not reduce nitrates. 



The members of the genus Aurococcus, as thus defined, 

 are normal inhabitants of the human epithelia and fre- 

 quent invaders of actively diseased tissues. In virulence, 

 various strains vary widely. Passage through animals 

 generally increases virulence, and the increase is more or 

 less specific for the species of animal used (Neisser and 

 Lipstein, 1903). A highly virulent culture will kill a 

 guinea pig of medium size in four to eight days if .1 cc. 

 be injected intravenously. Fever and wasting are ob- 

 served and autopsy shows the presence of numerous 

 local abscesses. 



It is from the standpoint of the pathologist that most 

 of the investigations upon these forms have been carried 

 out. These studies have concerned themselves mainly 



