We are all aware of the striking changes in the character of hospital populations, with reference to both the nature and the prognosis of the diseases for which patients are hospitalized. This is most apparent in the infectious diseases. Whereas in some diseases—typhoid and diphtheria—this is manifestly the result of improved hygiene and prophylactic public health measures, in others we have comfortably assumed that it is due to the prompt exhibition of antibacterial agents.
In the 24-year study from the Harriet Lane Home of The Johns Hopkins Hospital, reported in this issue, p. 1039, the earliest years showed the greatest proportion of empyemas accounted for by the pneumococcus, while the staphylococcus, the streptococcus, and Hemophilus influenzae accounted for a substantially smaller proportion. The incidence of pneumococcal empyema has decreased almost to the vanishing point, and deaths from pneumococcal empyema have ceased to occur. This is even more sweepingly true of