This figure comprises two line graphs which show the effect of antibiotics on death rates from childbirth-related infection and from all infectious disease, in England and Wales between 1931 and 1957. On both graphs, the year of introduction of each antibiotic or antibiotic class is indicated by a downward arrow. The horizontal axes are labelled year and are marked from 1930 to 1955 at 5-year intervals. The vertical axis for graph (a) is labelled maternal deaths per 100 000 births and is marked from zero to 120 at intervals of 40. The vertical axis for graph (b) is labelled deaths per million of population and is marked from zero to 1600 at intervals of 400. As shown by graph (a), following the introduction of sulphonamides, in 1935, childbirth-related infections fell rapidly from over 120 per 100 000 births to around 30 by the early 1940s, when penicillin was introduced; and by the 1950s annual death rates were close to zero. Graph (b) also includes the dates of introduction of later antibiotics: streptomycin in 1945, followed by chloramphenicol and tetracyclines by 1950. Deaths from all infectious disease fell from more than 1600 per million in the early 1930s to levels fluctuating between 1000 and 1300 by the early 1940s, when penicillin followed by streptomycin were introduced. Death rates had fallen to 500 by the late 1940s, when chloramphenicol and tetracyclines came into use, and by 1957 were down to 200 per million.