252 EPIDEMIC CEREBROSPINAL MENINGITIS 



meningococcus, and possessing a greatly increased bactericidal action as 

 compared with normal serum. Though the number of cases treated by 

 this method was not large, a distinctly favourable result was obtained. 



Allied Diplococci. — In the nasopharynx there occur other 

 Gram-negative diplococci which morphologically have a close re- 

 semblance to the meningococcus. Many of these are chromogenic, 

 e.g., m. catarrhalis flavus, and can thus be readily distinguished ; 

 others differ in their fermentative actions. Of these latter the 

 diplococcus or micrococcus catarrhalis has the closest resemblance 

 to the diplococcus intracellularis. In addition to occurring in 

 health this organism has also been found in large numbers in 

 catarrhal conditions of the pharynx and respiratory passages. 

 Its microscopic appearances are practically similar to those de- 

 scribed above, and it also occurs within leucocytes. Its colonies 

 on serum agar, though on the whole they tend to be rather 

 more opaque, closely resemble those of the meningococcus. 

 The organism usually grows on gelatin at 20° C. without lique- 

 fying the medium, and it has none of the fermentative properties 

 described above as belonging to the diplococcus intracellularis. 

 The diplococcus pharynr/is siccus (v. Lingelsheim) grows at room 

 temperature, and its colonies are very tough and adhere to the 

 surface of the medium ; it can thus readily be distinguished 

 from the meningococcus. It has marked fermentative properties, 

 acting on glucose, maltose, saccharose, and lsevulose. The 

 diplococcus mueosus has colonies of slimy consistence ; it grows 

 at room temperature, and it forms capsules, which can be 

 demonstrated by the method of Hiss. The points of difference 

 between the meningococcus and the gonococcus are given on 

 p. 258. There are various other Gram-negative species of diplo- 

 cocci, which can be readily distinguished, and which have no 

 pathogenic importance so far as is known. A Gram-positive 

 diplococcus called the diplococcus crassus is also of common 

 occurrence ; it is rather larger than the diplococcus intra- 

 cellularis, and especially in sub-cultures may tend to assume 

 staphylococcal forms. 



Meningitis due to other Organisms. — Meningitis may also 

 be produced by almost any of the organisms described in the 

 previous chapter, as associated with inflammatory conditions. 

 A considerable number of cases, especially in children, are due to 

 the pneumococcus. In many instances where no other lesions are 

 present the extension is by the Eustachian tube to the middle 

 ear. In other cases the path of infection is from some other 

 lesion by means of the blood stream. This organism also infects 

 the meninges not infrequently in lobar pneumonia, and in some 



