Pneumonic fever "is one of the severest, most common, and in cold and temperate climates, is productive of more deaths than any other acute disease," and "is, next to phthisis, the greatest enemy of mankind."
The prevalence of a disease may be studied in various ways,e. g., by considering; α. the annual mortality in relation (1) to the population, (2) to the deaths from all causes and (3) to the deaths from certain specified causes, and β. by comparing the annual mortality to (1) the population, (2) to that from all causes and (3) to that from specified causes.
Pneumonic fever is responsible for an annual mortality of 1.27 per 1000 of population. This estimate differs somewhat from those arrived at by Sanders,31.38; Hirsch, 1.49; Ziemssen, 1.53, and Osterlen, 1.85. Inasmuch, however, as the magnitude of the figures with which I deal is much greater than that of either of