Public health authorities campaigning against infant mortality and tuberculosis in the early twentieth century faced a problem very much analogous to that confronting the present-day cancer agencies. They knew a lot about the causes of infant mortality and tuberculosis, but were not always able or willing to use the knowledge they had. An important reason why many scientific findings were ignored or rejected was that the practical policies to which these findings seemed to lead were incompatible with the broader political and social goals of health campaigns. For example, studies linking infant mortality with poverty suggested that the well-being of infants could not be secured without a redistribution of economic resources between the well-todo and the poor, between the childless and those with children, or between men and women. Most policy makers influential in the formulation of health policies were against profound structural changes or considered them to be beyond the scope of their rightful duties. Thus evidence of the link between economic deprivation and infant mortality was not taken to be knowledge, but was treated as a controversial research finding.