True to the history of pandemics of influenza of the nineteenth century prepared by Leichtenstern,1 the great outbreak of last year has been followed by epidemic outbreaks chiefly in the larger cities. So far as conditions at Cook County Hospital obtain, Chicago was invaded early in January, 1920, and during the five weeks ending February 15, 1,128 patients were admitted to this institution. There were 264 deaths among this number, a mortality of 23.4 per cent., as compared to the rate of 31 per cent. at this hospital in the recent pandemic.
The crest of the epidemic (Chart 1) as indicated by admission to this hospital was reached on January 20, after a duration of about ten days. The secondary rise both in admissions and deaths occurred about January 30. This corresponds to the marked increase in the number of patients admitted with pneumonia.
Because of the rather limited