CHAPTER XIV. 

 THE MENINGOCOCCUS GONOCOCCUS GROUP. 



THE MENINGOCOCCUS GROUP. I THE GONOCOCCUS GROUP. 



Micrococcus Meningitidis. Micrococcus Gonorrheas. 



Parameningococcus. Micrococcus Catarrhalis. 



THE MENINGOCOCCUS GROUP. 



Micrococcus Meningitidis. Synonyms. Diplococcus intracellularis 

 meningitidis ; Diplococcus weichselbaumii, Meningococcus. 



Historical. Micrococcus meningitidis was isolated in pure culture 

 by Weichselbaum 1 from purulent cerebrospinal fluids of several typical 

 cases of cerebrospinal meningitis. The injection of pure cultures of 

 the organisms directly into the meninges of dogs resulted in well- 

 marked meningeal inflammation and encephalitis. Other organisms, 

 pneumococci, streptococci, Bacillus influenzse, for example, may incite 

 inflammations of the cerebrospinal membranes, but these bacteria 

 do not ordinarily cause epidemics of the disease. The meningococcus 

 frequently causes wide-spread infection, and, unlike the organisms 

 just mentioned (except the pneumococcus occasionally) the typical 

 lesions are primarily of the cerebrospinal axis. 



Morphology. Meningococci obtained directly from the cerebrospinal 

 fluid or from meningeal exudates occur characteristically in pairs with 

 their apposed sides flattened and somewhat elongated. They measure 

 about one micron in diameter, although the size varies even in the 

 same culture. The individuals are fairly uniform in size and shape 

 in very young, fresh cultures, but in older cultures considerable 

 variations in size are met with. Examined directly in inflammatory 

 exudates from the spinal fluid or meninges during the acute stages of 

 the disease, the organisms occur typically and characteristically as 

 intra- and extracellular diplococci and tetrads. They are found in 

 polymorphonuclear leukocytes, but never in lymphocytes or other 

 body cells. 2 They are intracellular but never intranuclear, according 

 to Councilman, Mallory and Wright. 



1 Fortschr. d. Med., 1887, Nos. 18 and 19.- 



2 Councilman, Mallory and Wright, Epidemic Cerebrospinal Meningitis. A Report 

 to the Mass. St. Bd. of Health, 1898, p. 75. 



