During the past forty years there have been four outbreaks of epidemic cerebrospinal meningitis in New York City. The first and, up to that of 1904 and 1905, the most severe epidemic was in 1872, when there were 782 deaths—a death rate of 8.70 per 10,000. In 1881 and 1893 the outbreaks were not so severe; the number of deaths were, respectively, 461 and 469, and the death rates 3.70 and 2.67. The latest epidemic, the severest in the history of the city, began in the early months of 1904 and continued through 1905. During 1904 there were 1,083 deaths and a death rate of 4.6; during 1905, 1,511 deaths and a death rate of 6.3.
The winters of 1872, 1881, 1893 and 1904 were what are known as "hard winters;" being cold, with considerable snow. The disease has always been abnormally prevalent for a year or two after each