TYPES OF MENINGOCOCCUS 293 



with the second serum, were tound to absorb agglutinin. 

 These eight cocci formed, therefore, type II. By the same 

 procedure two more types were differentiated among the 

 remaining strains, viz., types III and IV. The final result 

 was that of the thirty-two strains nineteen formed type 

 I, eight formed type II, four formed type III, and one 

 formed type IV. One specimen was amphoteric, quali- 

 fying for both types I and III. It is noteworthy that 

 no less than twenty-seven of the thirty-two meningococci 

 (84 per cent. ) were included in the first two types. Further 

 work has confirmed these results with the addition of a 

 few strains with anomalous reactions, and these have 

 been termed para-meningococci. 



Similar types of meningococci are also present in the 

 nasopharynx ; moreover, it a case of cerebro -spinal fever 

 has meningococci in the nasopharynx, the cocci in this 

 situation are of the same type as in the cerebro-spinal 

 fluid. Further, only one type is present in the cerebro- 

 spinal fluid of a case. The different types breed true, 

 maintaining their original serological characters. 



Pathogenesis . Monkeys may be infected by intra- 

 cerebral or intrathecal injection with the production 

 of a typical cerebro-spinal meningitis. Injected into the 

 peritoneal cavity of mice and guinea-pigs, or intra- 

 venously in rabbits, the meningococcus produces a fatal 

 septicaemia. 



Carriers. As already mentioned, the meningococcus 

 is present in the nasopharynx of a certain number of con- 

 tacts and others. The greater the closeness of contact, 

 the larger the proportion of infected contacts. Of 4,667 

 healthy non-contacts Bassett-Smith found the meningo- 

 coccus in fifty-three 1-124 per cent. ; of fifty-two 

 healthy contacts it was present in three = 5-77 per cent. 

 These figures have been much exceeded in other investi- 

 gations ; 10-13 per cent, of non-contacts have sometimes 



