In the first decades of the twentieth century, many colonial administrators, doctors and other agents in tropical Africa were haunted by the spectre of population decline. The idea that the African populations under their rule were declining, or at its best, stagnating, was at odds with core aspects of colonial ideology. A healthy and growing ‘native’ population was deemed indispensable to implementing the economic mise en valeur of the colonies and to attesting the very legitimacy of colonial agents as bearers of progress and civilization. Observers mentioned a wide variety of causes for depopulation, notably epidemic and endemic diseases, alcoholism, ‘native’ customs, labour conditions, outbound migration, low birth and high infant mortality rates. Accurate demographic data, however, were scarce.

In this presentation, I will focus on the role of medical doctors in producing and using demographic data in the Portuguese colony of Angola, during the Interwar Period. I will show that, in the second half of the 1920s, medical doctors began to collect demographic data on the Angolan population in a far more systematic way than before. This rise of medical demography was closely linked with new health programmes, which aimed at extending biomedical care to rural African populations. In the concept of social medicine that underpinned these programmes, demographic data were considered a fundamental tool. Acting as ‘field demographers’, doctors had recourse to new methods such as individual registration cards, sample techniques and oral interviews. Nevertheless, the collection of demographic data continued to depend on the collaboration of the African population, an issue which doctors’ reports assess in varied ways.

I will also argue that, while doctors collected information on all types of population ‘movements’ (natality, mortality and migration), they showed particular interest in natality related issues. This can be observed in other colonies too. It both reflected and reinforced a shift in colonial discourse on depopulation. In the Interwar Period, epidemic and endemic diseases were gradually being replaced by low fertility and high infant mortality as the most important factors of population decline/stagnation. Here, I will demonstrate that doctors used their demographic studies to dismiss the idea of low birth rates in Angola and to emphasize high infant mortality as the major problem to tackle.