382 APPLICATION OF METHODS OF BACTERIOLOGY 



The greatest variations are seen among cultures obtained 

 from healthy persons who have been associated with cases 

 of meningitis, i. e., "the carriers/' while the least degree 

 of variation is noted in cultures direct from the diseased 

 tissues. This is of special importance in indicating the 

 sources from which cultures should be derived that are to 

 be used in the immunization of animal whose serum is to be 

 employed for the treatment of the disease in man. 



Thus far two main groups or types of meningococci have 

 been established, and there is a possibility of further sub- 

 division of these types. 



Experience in this field shows the line of demarcation 

 between the two main types to be distinct, but for the pro- 

 posed subtypes it is less sharp than that for the other organ- 

 isms in which typing has succeeded, that is to say, in each 

 of the subgroups certain individual cultures may tend to 

 react in a manner suggesting characters common to members 

 of the other groups. 



In establishing the groups of this organism the method 

 used is that generally employed, i. e., the agglutinating 

 reaction with homologous immune serum. (See paragraph 

 on "varieties" in articles on Pneumococci and Strepto- 

 cocci.) 



ANTIMENINGITIS SERUM. 1 Flexner has demonstrated 

 that the blood serum of horses and of goats that have 

 received repeated subcutaneous injections of cultures of 

 diplococcus meningitidis possesses a marked restraining 

 action upon the course of meningitis. This is true not only 

 for the experimental manifestations of the disease, but for 

 those occurring in man as well. The analysis of about 400 



1 Flexner and Jobling, Arch, of Pediatrics, 1908, p. 747. 



