The employment of chemotherapy in cerebrospinal fever has resulted in a very large decline in the fatality rate. The fatality rate was halved in 1939, and in 1940 and 1941 it was < 1/3 of the average value. On the basis of the average fatality rate of 66.6% during 1934-7, the expected number of deaths in the 3 yrs. 1939-41 would have been 16,876. The number actually registered was 5,264, or 11,612 fewer than expected. Many factors influence the trend of the mortality from pneumonia, and consequently large fluctuations occur in the annual rates. These variations prevent a straight comparison being made between the number of deaths occurring in each yr. Although there has been an undoubted decrease in the mortality rate from pneumonia, an estimation of its extent is rather speculative. It seems probable that the deaths would have been 10% higher, and if the author can accept this as a not too optimistic approximation then 7,500 lives were saved during 1939-41. Puerperal sepsis forms numerically the most important component of maternal mortality. In the 10 yrs. preceding the war 40% of the total maternal deaths were attributed to this cause. Mortality from puerperal sepsis had declined considerably and the rate during 1940-1 had decreased to < 1/2 the value of a few yrs. earlier. A considerable decrease in mortality from measles has occurred during the past 20 yrs. Serum prophylactics have been employed during the past decade, and special therapeutic measures[long dash]e.g., oxygen therapy[long dash]have probably influenced the trend of mortality.