The earlier clinical and pathologic studies of certain infectious diseases, among others, pneumonia, typhoid fever, gonorrhea and epidemic meningitis, indicated a marked predilection of the specific excitant to localize in certain definite tissues. The introduction of more accurate methods for clinical investigation, and of additional refinements in bacteriologic technic have afforded substantial evidence that the distribution of the causal agent in such disorders is not so limited as was formerly presumed.
Following the identification in 1887 of the Meningococcus intra-cellularis by Weichselbaum1 as a separate species, and the establishment of its specific relation to epidemic meningitis, investigations were conducted to determine the presence of this microorganism in the blood and in the lesions complicating this disease.
The biologic characteristics of the meningococcus rendered such investigations particularly difficult. The susceptibility of the organism to outside influences and its intracellular position made it difficult to cultivate under the