558 INFECTION AND IMMUNITY. 



only for a few days at room temperature. When 

 dried on paper and exposed to the sunlight it lives 

 no longer than twenty-four hours, in a dark room 

 seventy-two hours (Councilman, Mallory and 

 Wright). It is killed by a temperature of 65 C. 

 for thirty minutes (Albrecht and Ghon). 

 virulence; The meningococcus has little virulence for ani- 

 mals. When injected in sufficient quantity into 

 the peritoneal or pleural cavity of white mice 

 death results in from twenty-four to forty-eight 

 hours, but not when given subcutaneously. Men- 

 ingitis may be produced by subdural injections, 

 but the disease does not resemble the epidemic 

 meningitis of man. So far as is known at present 

 the organism does not produce a soluble toxin, but 



possesses rather an endotoxin. Although the dis- 

 infection . ,, , ,, . ... 

 Atria, ease is usually spoken of as a primary meningitis, 



there is reason to believe that it is secondary to an 

 acute rhinitis or acute inflammation of the acces- 

 sory sinuses or middle ear, in many instances. 

 From these places the coccus may readily reach the 

 meninges by way of the lymphatic channels, or 

 blood. The latter, according to Elser and Hun- 

 toon, is probably the usual route. It has been 

 found repeatedly in the noses of those associated 

 with patients with the disease; in such cases an 

 acute rhinitis may be present without the subse- 

 quent development of meningitis. The clinical his- 

 tory shows that the infection commonly is preceded 

 by acute rhinitis. The inflammation in the menin- 

 ges is always cerebrospinal in its distribution and 

 is characterized by a purulent or fibrino-purulent 

 exudate in which the diplococci are present in 

 varying quantities. Diagnosis may often be estab- 

 lished clinically by the microscopic or cultural 



