During the period Sept. 23, 1917, to July 15, 1918, there were admitted to the Medical Service of the U. S. Army Base Hospital, Fort Riley, 191 patients with meningococcic meningitis and twenty-four patients with meningitis due to other organisms. It is the purpose of this article to review the important diagnostic features presented by this series and to draw certain conclusions from the methods of treatment employed. INCIDENCE During the period, Sept. 23, 1917, to June 3, 1918, the date of admission of the last meningococcic meningitis patient, there were admitted to this hospital 24,406 patients. The incidence of meningococcic meningitis to all hospital admissions was, therefore, 0.77 per cent. These admissions were secured from Camp Funston, which housed the 89th and 92nd Divisions of the Army; the Medical Officers' Training Camp, and the Fort Riley Post. The largest number of patients with meningitis was from the recruits at