In twenty-five consecutive cases in which nasopharyngeal cultures have been made from patients suffering from bacteriologically proved cerebro-spinal meningitis, meningococci have been obtained.

A striking similarity between the organisms from the two sites has been shown to exist for not only are they of the same agglutinable type but in the majority of instances individual peculiarities of agglutination have corresponded. The closeness of relation has been further demonstrated by the carbohydrate reaction in one case in which the unusual property of bleaching glucose litmus broth to a yellow colour was possessed by both organisms. Nevertheless, in a certain number of instances, though organisms of a different agglutinable type have not been isolated, as by other workers, there have been found certain minor variations of agglutination. That most if not all of these variations are due to alteration of the agglutinable capacity of one of the organisms seems probable, as in the six cases where most marked difference existed (Nos. 1, 3 and 24 of Type I and Nos. 15, 16 and 18 of Type II) the chances of the other alternative, namely that a second infection had happened in each case to be of the same agglutinable type, are remote.

In the twenty-five cases the proportion of the types present has been shown to agree with that found by other workers during the same period. Seven of the infections (28 per cent.) have been due to Type I and eighteen (72 per cent.) to Type II.

Ten of the cases have occurred in children under the age of two years, and the proportion of the two types among them has been approximately the same as among older patients.

The writer is indebted to the members of the staff of St Bartholomew's Hospital for permission to publish their cases, and gratefully acknowledges the encouragement and assistance of Professor Andrewes at whose instigation these investigations were conducted.