Journal of the Plague Year

by Daniel Defoe

The bubonic plague first hit London in 1349, killing between one-third and one-half of the population. After that it hung around sullenly, flaring up occasionally but mostly satisfying itself with a handful of victims. Typically a decade or two would pass between visitations. A few of the outbreaks were serious, killing tens of thousands. The last big outbreak was in the year 1665, and it was a lunker: more than 100,000 people died in London alone.

Daniel Defoe was four years old at the time and had no idea what was going on. But more than 50 years later he wrote this book about the Plague. His basic source material was a lengthy journal kept by his uncle, one Henry Foe. (The author had been born Daniel Foe, but around 1695 he changed his name to Daniel Defoe because he thought it flashier, possibly in the belief that a vaguely French-sounding name would have greater cachet.) Defoe then researched his topic thoroughly, gathering together all the first-person reports he could find, along with the official Weekly Bills, which summarized total deaths throughout London each week.

Next, Defoe assembled a fictitious story “based on actual events”. The version he presented teemed with fictitious embellishments that served to dramatize the events. Most of the literature published about the Plague had taken a high-level view, addressing the progress of the Plague, the number of deaths, where the deaths were concentrated each week, how officials dealt with it, and so forth. Defoe’s stroke of genius was to make it a personal experience. It was the first “You are there!” historical narrative, and it was a massive hit.

Defoe was masterful in his weaving of fact and fiction; even today, it’s impossible for scholars to figure out which parts were fictitious and which parts were true. The most likely fiction is the long tale of the group of people who fled London and tried to find a haven outside of the city. They were repulsed at the gates of every town they approached, but in one case the town agreed to provide food to the travelers if they would agree to remain in a nearby forest.

The people had little idea how to resist the Plague; their only solid preventative was to avoid contact with infected persons. Inasmuch as the disease had a long incubation period in which no symptoms were observable, even this precaution had limited value. They killed every other animal they could: dogs, cats, mice, and rats, not realizing that the rats were the greatest threat and the cats and dogs were valuable means of holding down the rat population. They also believed that burning coal was of some value, so they kept up coal fires in their fireplaces and even in public intersections. If anything, it made matters worse by compromising their lungs.

The most striking realization for me concerned Defoe’s declaration that, while mortality fell in late September even though morbidity remained constant. In other words, people were still getting sick, but fewer were dying. Defoe presents a goodly amount of evidence to support his claim, and it strongly suggests that people were building up immunity to the disease. This may explain why the disease flared up at intervals of a decade or two: during the intervening time, a new generation of immunologically virgin people took their places in the population until there was a critical mass of potential victims, at which point the plague burst out of the nooks and crannies where the rats hid.

There may also be something about the rat population that influenced plague outbreaks. It seems likely that the plague was even more devastating to the rat population than to the human population; if so, then it might have taken some time for the rats to repopulate the city. This would suggest a double whammy: in the immediate aftermath of the plague, there were too many immune persons and too few infected rats. For years, the populations of both species grew, and the overall vulnerability to the plague would increase as the product of the two population sizes. Thus, when the plague did hit, it hit hard.

After the Great Plague of 1665, there were no more serious epidemics of plague in England. Why? Perhaps enough immunity-conferring genes worked their way into the population to give it some innate resistance. Perhaps their countermeasures, primarily in keeping down the rat population, were the trick. The plague continued to strike on the continent for another hundred years. Whatever happened in England after 1665 also happened in Europe during the 18th century.