Cerebrospinal meningitis prevailed as an epidemic in Greater New York City during the winter of 1904 and the spring of 1905. Since that time up to the present writing, sporadic cases of meningitis still arise. In the spring of 1905 the Health Department of New York City appointed a commission to co-operate with the department in investigating the epidemic. As a member of the commission I undertook an experimental investigation of meningitis out of which the preliminary report has grown. The full report of this investigation will appear in a forthcoming number of the Journal of Experimental Medicine.
The bacteriologic examination of the exudates from the meninges, obtained by lumbar puncture and at autopsy, showed the epidemic to be caused by Diplococcus intracellularis of Weichselbaum. My work was done almost entirely with this micro-organism. The sources of my cultures were the following: Dr. E. K. Dunham, Dr. Martha Wollstein and