The specific relation of the diplococcus of Weichselbaum to epidemic cerebrospinal meningitis is established beyond question. Investigations of the last few years have aimed to solve the mystery as to the sources of infection and the route taken by the invading organism in reaching its objective point in the meninges of the brain and cord. The first light on these questions came from the discovery of Albrecht and Ghon¹ that organisms morphologically identical with the Diplococcus intracellularis could be found in the nasal secretions of some of the patients. This observation was quickly followed by the proof that, while some of these organisms resembling the diplococcus of Weichselbaum belonged to other species, there was no doubt that the specific excitant of meningitis could be found in the nasal fossæ of some of the patients and also of others who have not had the disease but had come