The wave of poliomyelitis which swept over the United States last summer helped to clear up some obscure and disputed points in its epidemiology. From the standpoint of preventive medicine, a knowledge of the mode of contact, transmission and communicability is essential in order to control the spread of disease. The material on which this paper is based was obtained from a study of 4,186 cases reported to the New York State Department of Health from June to December, 1916. This does not include the cases occurring in the city of New York.
The age incidence in the state differed somewhat from that in the city, as 55 per cent. of the cases occurred in children under 5 years of age, as compared with 90 per cent. in New York City. Poliomyelitis was almost entirely a disease of childhood in the city of New York, where there were only 1.7