250 RELATIONSHIPS OF THE COCCACE^E 



very abundant surface growths. Planes of fission often 

 parallel, producing pairs, or short or long chains, never 

 packets. Generally stain by Gram. Produce acid in dex- 

 trose and lactose broth. Pigment, if any, white or orange. 



Genus I. Diplococcus (Weichselbaum) Winslow and 

 Rogers. 



Strict parasites, not growing, or growing very poorly, on 

 artificial media. Cells normally in pairs, surrounded by a 

 capsule. Fermentative powers high, most strains form- 

 ing acid in dextrose, lactose, saccharose, and inulin. 

 Hemolytic power generally lacking. Characteristic group 

 serum reactions. 



Species i. D. pneumonice Weichselbaum. 



A coccus occurring commonly in the body, in pairs 

 of elongated lanceolate cells, surrounded by a capsule. 

 Stains by Gram. On media often in short chains. 

 Growth on media faint, producing small translucent disk- 

 like surface colonies. Ferments monosaccharides, disac- 

 charides, and inulin. Lacks hemolytic power. Virulence 

 very variable. Shows characteristic group serum reactions. 

 Occurs in normal or pneumonic sputum and in infected 

 tissues in pneumonia. 



Species 2. D. gonorrhoece (Neisser) Flugge. 



A coccus occurring commonly in pairs of flattened coffee- 

 bean shaped cells. Decolorizes by Gram. Fails to 



