CHAPTER XLVII. 

 THE MENINGOCOCCUS. 



Introduction. 



Section I. Experimental inoculation, p. 645. 



Section II. Morphology, p. 645. 



1. Microscopical appearance and staining reactions, p. 645. 2. Cultural charac- 

 teristics, p. 647. 

 Section III. Biological properties, p. 647. 



1. Bio-chemical reactions, p. 647. 2. Vitality and virulence, p. 648. 3. Toxins, 

 p. 648. 4. Immunization and serum therapy, p. 648. 5. Agglutination, p. 649. 

 Section IV. The isolation and identification of the meningococcus, p. 650. 



1. The diagnosis of meningococcal meningitis, p. 650. 2. The isolation of the 

 organism, p. 650. 



Micrococcus catarrhalis, p. 651. 



EPIDEMIC cerebro-spinal meningitis x is generally caused by the Diplococcus 

 intra-cellularis meningitidis discovered by Weichselbaum and now generally 

 known as the Meningococcus. 



Though the Meningococcus is the most frequent cause of the disease (especially 

 in recent epidemics) it is of course not the only cause of epidemic meningitis. 



In some cases of epidemic meningitis a typical pneumococcus has been 

 recovered from the cerebro-spinal fluid (Won , Netter and others), and Marchoux 

 described an epidemic of cerebro-spinal meningitis in Senegal which was due to the 

 pneumococcus. 



In another epidemic of cerebro-spinal meningitis Jaeger and Heubner found an 

 organism quite distinct from the Meningococcus (p. 626). Bonome, again, described 

 an encapsulated gram-positive streptococcus as the cause of an epidemic of cerebro- 

 spinal meningitis : this organism has also been demonstrated in a large number 

 of cases of meningitis, particularly by Netter : it is commonly found in association 

 with the Meningococcus. 



The Meningococcus is present in the cerebro-spinal fluid and in the fluid 

 exudate on the meninges in cases of meningitis : it occasionally enters the 

 blood stream (Salomon, Elser, Sacquepee, etc.). It has been shown that 

 meningococcal cerebro-spinal meningitis is always preceded by a more or less 

 well marked naso-pharyngitis, with symptoms of sore throat and coryza, due 

 to infection with the meningococcus (Strumpell, Weigert, Albrecht and Ghon, 

 Kiefer, Jundell, etc.). According to Ostermann it is this naso-pharyngitis which 

 is contagious and disseminates the meningococcus. Some individuals affected 

 with pharyngitis escape an attack of meningitis, which only supervenes when 

 the organism under conditions still little understoodpasses from the naso- 



[*The expression "epidemic meningitis" is very commonly used to connote meningo- 

 coccai meningitis. Such a limitation of the meaning is, of course, very misleading.] 



