LET'S REMINISCE: The birth of epidemiology
Throughout most of the seventeenth century, residents of London could buy, from street hawkers, a peculiar sort of newspaper. It cost a penny, sold about five or six thousand copies a week, and consisted of a single page. On one side, readers would learn how many of their neighbors had died the previous week, in each parish. On the other, readers would learn what was believed to have killed them.
“Jaundice” was common, as was “Apoplex,” an old word for a stroke, and “Dropsie,” which meant swelling. Other entries seemed to answer the question “How did he die?” with descriptions—“Dead in the Streets” or “Stilborn” or “Suddenly”—instead of actual causes. The deaths were usually assessed and recorded by pairs of older women, who were employed by parishes to go to the local church whenever its bell tolled a death.
During one February week in 1664, these searchers, as they were known, recorded three hundred and ninety-three burials across the city. Death causes and counts ranged from “Aged” (thirty-two victims) and “Consumption” (sixty-five) to “Scalded in a Brewers Mash” (one).
For the same reasons that today’s newspapers report coronavirus case numbers on their front pages, these London papers, known as Bills of Mortality, became particularly popular when disease swept through the city. During the 1665 plague, Samuel Pepys wrote in his diary about feeling saddened or cheered by the latest numbers from the Bills, while a contemporary named John Bell noted that the Bills allowed people to know “the places which are therewith infected, so such places may be shunned and avoided.”
But most of the time, according to the London merchant John Graunt, the Bills were little more than matters of curiosity, especially if there were deaths that were “rare, and extraordinary in the week current.” He didn’t consider this to be odd or unseemly. Death, after all, was the most basic fact of life.
Eventually, though, Graunt began to wonder if the Bills could be put to “other, and greater uses.” He painstakingly collected and organized decades of the death records, creating long tables of numbers. These first known tabulations of population-level health data are now widely recognized as the birth of epidemiology.
Graunt pored over them. What types of death were most common? Which groups did they afflict? Why did some causes spike at certain times, while others stayed fairly constant? And, most of all, what could a lot of separate, individual deaths, taken together, tell him about the society in which they occurred? Although Graunt wanted, as he put it in a treatise, to understand “the fitness of the Country for long Life,” he believed that it was in its deaths that he would find answers.
In a new book, Steven Johnson credits John Graunt with creating history’s first “life table”—using death data to predict how many years of remaining life a given person could
expect. In fact, Graunt’s estimates were more of a guess than a calculation: when he wrote his treatise, in the 1660s, the Bills of Mortality didn’t record people’s age at death, and they wouldn’t for another half century. Yet his guesses about survival rates for different age groups turned out to be remarkably accurate. For most of our long history as a species, our average life expectancy was capped at about thirty-five years.
Johnson calls this phenomenon “the long ceiling.” Analysis of ancient burial sites, of modern people living in hunter-gatherer societies, and of pre-industrial city dwellers all tell a similar story, Johnson writes: “Human beings had spent ten thousand years inventing agriculture, gunpowder, double-entry accounting, perspective in painting, but these undeniable advances in collective human knowledge had failed to move the needle in one critical area.”
John Graunt is remembered today as the father of data-driven epidemiology, but you could argue that his greatest insight was simpler, and deeper: that you could tell a lot about how people lived within a society by the way they died. He also realized that seeing those patterns offered an opportunity to try to change them.
Jerry Lincecum is a retired Austin College professor who now teaches classes for older adults who want to write their life stories. He welcomes your reminiscences on any subject: firstname.lastname@example.org.