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Enslaved people and the birth of epidemiology

Illustration of a ship used to carry enslaved people

An eighteenth-century engraving shows how a ship carried more than 600 enslaved people.Credit: Private Collection/AF Fotografie/Alamy

Maladies of Empire: How Colonialism, Slavery, and War Transformed Medicine Jim Downs Belknap (2021)

“History performs a social task,” wrote George Rosen in his classic 1958 book A History of Public Health. “It may be regarded as the collective memory of the human group and for good or evil helps to mold its collective consciousness.” Rosen’s book grounded modern US public health in the experiences of European immigrants in urban areas. It scarcely mentioned ill health among enslaved or formerly enslaved people — but his words were prescient.

Historian Jim Downs has now given global context to nineteenth-century advances in medicine and public health, beyond the dominant histories rooted in Western Europe and the ancient world. In Maladies of Empire, he centres slave ships, people living in colonized countries, prisoners and wars in the narrative of medical discovery, at the foundation of epidemiology. He barely mentions what is often cited as the field’s origin story, when British doctor John Snow removed the handle from a London water pump and ended a cholera outbreak in 1854.

Downs’s first goal is to “make visible” how epidemiological thinking emerged from imperial conquest and the exploitation of enslaved people. He delves into archival records to recount how Western medical men — they were nearly always men — drew on the transatlantic slave trade. These researchers studied the health consequences of enslavement and thence began to understand disease transmission. For example, the study of ventilation emerged from the holds of slave ships and crowded prison cells. British and other European doctors observed and discussed cholera outbreaks in the Caribbean and elsewhere before Snow stopped one in London.

The grisly record-keeping of the trade in enslaved people and colonial governments provided the infrastructure for epidemiological data collection. Downs shows how logs of sickness and death on slave ships, in prisons and at quarantine stations — unmentioned in standard histories — were central to the emergence of public health. A bureaucracy “established in the service of war, colonialism, and imperialism emerged as the foundation for the development of epidemiology”. Downs provides history as truth-telling.

His second goal — to put marginalized people into the historical record as active creators of knowledge — is more vexed. He frequently notes how enslaved and other oppressed people “made visible” patterns of disease. For example, when ventilators pumped in fresh air, the cries from captured Africans packed below deck declined. Downs makes an argument that their moans served to create knowledge and ensured that they “were not simply passive objects”. Perhaps he seeks to honour these enslaved individuals who advanced medical knowledge with their bodies but without their consent. But I struggle to see how deeming their experiences ‘knowledge generation’ restores dignity to people subjected to barbaric treatment.

Agency returned

Finally, Downs takes issue with how epidemiology strips data of human agency. This is a valuable point. He argues that knowledge should arise from the perspective of those most affected. How to achieve this in the field of epidemiology is less clear. For example, Downs notes how a nineteenth-century observation that washerwomen in Malta did not contract the plague, despite their presumed exposure, left the women unnamed. This omission would probably still happen today. Epidemiology concerns itself with gleaning population-health patterns expressed as numbers, not personal stories. The COVID-19 pandemic has shown how the public becomes inured to numbers. In the United States, people who were over 65 account for three-quarters of COVID-19 deaths. But this does not tell the full cost — for example, to Indigenous peoples who have lost precious native speakers of their languages. Storytelling must exist alongside, not within, epidemiological methods.

To bring a human dimension absent from the historical record, Downs offers fictionalized accounts. The book begins by recounting details of an enslaved man on board a ship. Originally from “Ghana”, he was sold in “revenge” when accused of “witchcraft” after quarrelling with a “chief”. In my view, these clichés detract from the purpose of imagining the real people who were subjected to brutality.

Erased histories

Maladies of Empire also adds to better-known histories. It reminds us that Florence Nightingale, the pioneering nineteenth-century British nurse, was an accomplished statistician. Her graphical representations of data on mortality presaged sociologist W. E. B. Du Bois’s equally striking visualizations of demographic characteristics of the newly freed Black population at the end of the nineteenth century. Downs also examines evidence that during the US Civil War, which ended legal slavery in the country, Southern physicians intentionally infected enslaved children to produce material for smallpox vaccinations.

A chilling chapter tracks how the US Sanitary Commission (USSC), a private relief agency that supported Union soldiers — including Black soldiers — during the Civil War helped to solidify the idea that races were biologically distinct. For example, USSC physicians made “scientific” studies of alleged differences, dispatching doctors to monitor Black soldiers as they bathed, and score various physical characteristics. As a result, race, rather than the terrible living conditions of the newly freed Black population, was thought to explain poor health. The legacy of this history lives on in present-day public health and medicine — for example, in algorithms that propagate race-based decisions in the clinic.

As many institutions and disciplines attempt to resituate imperialism, slavery and colonization as central elements, not aberrations, of the modern era, Downs contributes to the studies showing that medicine and public health share these erased histories. He recovers lost and untold stories and makes visible things that need to be seen.

Nature 604, 617-618 (2022)


Competing Interests

The author declares no competing interests.


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