The constant change in the frequency of disorders of the human body is well illustrated by the decreasing incidence of infectious diseases in civilized countries. Probably the most striking example, especially for those whose medical memories extend thirty years or more, is typhoid. At present the trends of other infectious diseases, such as diphtheria,1 are of particular interest.
Useful recording and statistical interpretations of disease trends are those appearing in the Epidemiological Reports of the Health Section of the Secretariat of the League of Nations. In a recent issue2 it was proposed to show that a decline has occurred in the deaths caused by whooping cough and measles similar if not equivalent to that in diphtheria and scarlet fever. Attention was also drawn to the relative social importance of these four infectious diseases of childhood, since "the traditional fear inspired by scarlet fever and diphtheria is no more