The Diplocuccus intracellularis was identified as the specific excitant of epidemic cerebrospinal meningitis by Weichselbaum in 1887. The procedure of lumbar puncture as a means of obtaining cerebrospinal fluid and attaining an etiologic diagnosis in cases of meningitis was introduced by Quineke in 1891.
The studies of meningitis made possible by this means have established beyond question the relationship of the meningococcus to the epidemic type of meningitis which has presented itself in various parts of the world during the last decade. As this relationship has been made clear, the problem of the control of this dreaded disease has focused itself about the life of the specific organism, its distribution in the body of those affected by the disease, its paths of exit from the body, its viability, and the mode by which the infection might be conveyed to others. Most of the points of interest and importance in these