428 Cerebrospinal Meningitis 



dead. This is confirmed by the microscopic appearance of 

 the cultures. Those sixteen to twenty-four hours old stain 

 sharply and uniformly; on the second day many of the cocci 

 show irregularities of size and staining, and after several 

 days no normal-looking cocci can be found. It was found, 

 however, that in carefully preserved cultures of certain 

 strains a few cocci might survive for many months. Vitality 

 is preserved longest when the cultures are kept in the 

 thermostat and not taken out when grown, and kept at 

 room temperature or in a refrigerator. The addition of a 

 small quantity of a calcium salt favors prolonged vitality 

 and will sometimes maintain it for four or five weeks in cul- 

 tures that would otherwise die in a few days. Sodium 

 chlorid is injurious to the cocci. Flexner attributed the 

 autolysis of the cultures to an enzyme. 



The organism is soon killed by drying, by exposure to the 

 sun, and by quite moderate variations of temperature. It 

 succumbs to very high dilutions of most germicides in a very 

 short time. 



Agglutination. When animals are immunized by repeated 

 injections of the Diplococcus intracellularis, their blood- 

 serum and body- juices become agglutinative. Such serums 

 kept in the laboratory can be used for the identification of 

 the coccus in fresh culture, though the reaction is not exact, 

 since the agglutinability of different strains of cocci is differ- 

 ent. The serums have an agglutinating power that varies 

 from i : 500 to i : 3000 in the hands of different observers. 



Metabolic Products. The meningococcus produces an 

 endotoxin. Albrech and Ghon* were able to kill white mice 

 with dead cultures. Lepierre | obtained a toxin from bouillon 

 cultures by precipitating them with alcohol. 



Pathogenesis. The results of animal inoculations made 

 with Diplococcus intracellularis meningitidis are disappoint- 

 ing. Subcutaneous inoculations into the lower animals are 

 continually without effect. Intrapleural and intraperito- 

 neal injections of cultures of the organism into mice and 

 guinea-pigs are sometimes fatal, the dead animals showing 

 a serofibrinous inflammation with the presence of the cocci. 

 The intravenous injection of the coccus into rabbits is 

 followed by death without important or conclusive symp- 

 toms, and usually without the presence of cocci in the blood. 



* "Wiener klin. Wochenschrift," 1901. 



t " Jour, de phys. et de path, gen.," v, No. 3. 



