MICROCOCCUS INTRACELLULARIS MENINGITIDIS 377 



often preceded by nasal catarrh, may take place along the paths of the 

 lymphatics, passing out of the nose and its accessory cavities toward the 

 base of the skull. These facts, together with the low resistance shown 

 by the meningococcus against drying, and the general failure so far to 

 demonstrate it in air, dust, or fomites, would seem to indicate that trans- 

 mission usually occurs directly from one human being to another. 



The disease produced in man consists anatomically in a suppxirative 

 lesion of the meninges, involving the base and cortex of the brain and the 

 surface of the spinal cord. The nature of the exudate may vary from a 

 slightly turbid serous fluid to that of a thick fibrinous exudate. In 

 chronic cases encephalitis and dilatation of the ventricles may take 

 place. Apart from their presence in the meninges and in the naso- 

 pharynx, meningococci have not been satisfactorily demonstrated in 

 any of the complicating lesions of the disease. Reports of their presence 

 in the conjunctivae, in the bronchial secretions from broncho- or lobar 

 pneumonia, and in otitis media, have usually been based upon insuf- 

 ficient bacteriological evidence. 



The occurrence of this microorganism in the circulating blood of men- 

 ingitis cases has been definitely proved by Elser,^ who found it in ten 

 cases. 



Animals are not very susceptible to infection with Diplococcus 

 meningitidis. Subcutaneous inoculation is rarely followed by more 

 than a local reaction unless large quantities are used. White mice are 

 rather more susceptible than other species. Intraperitoneal and intra- 

 venous inoculation of sufficient quantities usually results in the death 

 of mice, rabbits, guinea-pigs, and dogs. Occasional strains have been 

 found to possess a not inconsiderable degree of toxicity for rabbits, 

 grave symptoms or even death following intravenous injection of but 

 moderate quantities without any traceable development of the micro- 

 organisms in the organs of the animals. 



Similar observations have been made by Albrecht and Ghon,^ who 

 succeeded in killing white mice with dead cultures. It would seem 

 therefore that the effect of this coccus upon animals depends chiefly 

 upon the poisonous substances contained in the bacterial bodies (endo- 

 toxins) . Lepierre ' has obtained the meningococcus toxin by alcohol 

 precipitation of broth cultures. 



Weichselbaum himself succeeded in producing meningeal suppura- 



1 Elser, Jour. Med. Res., xiv, 1906. 



2 Albrecht iind Ghon., loc. cit. 



^Lepierre, Jour, de phys. et de path, gfe., v, No. 3. 



