GRAM-NEGATIVE COCCI 295 



Taylor * has shown that the use of a meningococcal 

 vaccine produces a high antibody content (agglutinins) in 

 the blood, but that none of these substances passes over 

 into the cerebro-spinal fluid. 



The Gram -negative Cocci of the Upper Respiratory 



Tract 



It may be of service here to describe certain Gram- 

 negative cocci which are met with in the nasopharynx 

 and to contrast them with the meningococcus. 



Micrococcus pharyngis siccus. Common. Grows freely, forming 

 white and adherent colonies. Develops at 23 C. and rapidly 

 ferments glucose and saccharose. 



Micrococcus flavus I. Common. The colonies, first whitish, 

 soon become yellow, and on touching them they tend to slide 

 about and may be picked up whole. Develops at 23 C. and 

 ferments glucose and saccharose in three to four days. 



Micrococcus flavus II. Rare. More delicate in growth than 

 the preceding. Colonies become yellow and are sticky and 

 stringy. Easier to subculture than the preceding. Ferments 

 glucose and saccharose slowly, and the change is often earlier in 

 saccharose. 



Micrococcus flavus III. -Not common. Colonies of a canary- 

 yellow and of the consistency of paint. Two forms are described, 

 one growing strongly at 23 C. in twenty-four hours, the other 

 failing to grow at this temperature. Ferments glucose in four 

 days, but fails to ferment saccharose. 



Micrococcus catarrhalis. Not uncommon. Colonies whitish 

 and like paint, easily emulsified. Growth at 23 C. is feeble. No 

 sugars are fermented (see also p. 303). 



Meningococcus. Colonies whitish, or with the faintest yellowish 

 tinge, of consistency like paint and easily emulsified. Rarely 

 grows at 23 C. Ferments glucose, but not saccharose. Mannose 

 first becomes acid and then alkaline. The Diplococcus crassus, 

 which is Gram -positive, and the D. mucosus, which is Gram- 



1 Lancet, 1918. 



