The Ghost Map

by Steven Johnson

  [Any] Dwelling House or Building in any City, Town, Borough, Parish, or Place within or over which the Jurisdiction or Authority of the Town Council, Trustees, Commissioners, Guardians, Officers of Health, or other Body to whom such Notice is given, extends, is in such a filthy and unwholesome Condition as to be a Nuisance and injurious to the Health of any Person, or that upon any Premises within such Jurisdiction of Authority there is any foul or offensive Ditch, Gutter, Drain, Privy, Cesspool, or Ashpit, or any Ditch, Gutter, Drain, Privy, Cesspool, or Ashpit kept or constructed so as to be a Nuisance to or injurious to the Health of any Person, or that upon any such Premises Swine, or any Accumulation of Dung, Manure, Offal, Filth, Refuse, or other Matter or Thing, are or is kept so as to be a Nuisance to or injurious to the Health of any Person, or that upon such Premises…

  To abide by these new laws, though, you needed somewhere to put all that “manure, offal, and filth.” You needed working sewers. London actually had an ancient drainage system that had evolved around a dozen creeks and small rivers that continue to flow beneath the city to this day. (The largest waterway, the Fleet River, runs beneath Farringdon Road, emptying into the Thames under Blackfriars Bridge.) Parliamentary bills governing the construction of new sewers date back to the days of Henry VIII. Historically, however, London’s sewers had been designed to carry off the city’s surface water. Until 1815, it was illegal to discharge raw waste into the sewers. If your cesspool was overflowing, you called the night-soil men. This system resulted in some foul-smelling cellars, but it left the waters of the Thames remarkably pristine, with a bustling fisherman’s trade working the river between Greenwich and Putney Bridge. But as the city’s population exploded, and as more and more houses discharged their waste into the existing sewers, the quality of the Thames water declined at an alarming rate. What’s more, the sewers themselves began to clog, leading to the occasional underground explosion of methane gas.

  Chadwick’s work in the 1840s and early fifties had the perverse effect of exacerbating this problem, both through his position as head of the Board of Health and his seat on the newly formed Metropolitan Commission of Sewers. There was much squabbling and drafting of plans for expanding the city’s sewage system, but nothing practical was done for years, until a brilliant engineer named Joseph Bazalgette took charge of the project. In the meantime, the primary focus was on eliminating cesspools. As Bazalgette would later report: “Within a period of about six years, thirty thousand cesspools were abolished, and all house and street refuse was turned into the river.” Several times a year, the Commission’s engineers would offer enthusiastic reports documenting just how much waste had been extracted from the city’s houses and deposited in the river: 29,000 cubic yards in the spring of 1848, growing quickly to 80,000 cubic yards the following winter. In the space of about thirty-five years, the Thames had been transformed from a fishing ground teeming with salmon to one of the most polluted waterways in the world—all in the name of public health. As the builder Thomas Cubbitt observed wryly: “The Thames is now made a great cesspool instead of each person having one of his own.”

  Herein lies the dominant irony of the state of British public health in the late 1840s. Just as Snow was concocting his theory of cholera as a waterborne agent that had to be ingested to do harm, Chadwick was building an elaborate scheme that would deliver the cholera bacteria directly to the mouths of Londoners. (A modern bioterrorist couldn’t have come up with a more ingenious and far-reaching scheme.) Sure enough, the cholera returned with a vengeance in 1848–1849, the rising death toll neatly following the Sewer Commission’s cheerful data on the growing supply of waste deposited in the river. By the end of the outbreak, nearly 15,000 Londoners would be dead. The first defining act of a modern, centralized public-health authority was to poison an entire urban population. (There is some precedent to Chadwick’s folly, however. During the plague years of 1665–1666, popular lore had it that the disease was being spread by dogs and cats. The Lord Mayor promptly called for a mass extermination of the city’s entire population of pets and strays, which was dutifully carried out by his minions. Of course, the plague turned out to be transmitted via the rats, whose numbers grew exponentially after the sudden, state-sponsored demise of their only predators.)

  Why would the authorities go to such lengths to destroy the Thames? All the members of these various commissions were fully aware that the waste being flushed into the river was having disastrous effects on the quality of the water. And they were equally aware that a significant percentage of the population was drinking that water. Even without a waterborne theory of cholera’s origin, it seems like madness to celebrate the ever-increasing tonnage of human excrement being flushed into the water supply. And, indeed, it was a kind of madness, the madness that comes from being under the spell of a Theory. If all smell was disease, if London’s health crisis was entirely attributable to contaminated air, then any effort to rid the houses and streets of miasmatic vapors was worth the cost, even if it meant turning the Thames into a river of sewage.

  CHADWICK MAY HAVE BEEN THE MOST INFLUENTIAL MIASmatist of his age, but he had plenty of illustrious company. The other great social crusaders of the age were equally convinced of the connection between foul air and disease. In 1849, the Morning Chronicle sent Henry Mayhew to the heart of the cholera epidemic, in the Bermondsey neighborhood south of the river. The account eventually published deserves its own distinct journalistic genre—olfactory reporting:

  On entering the precincts of the pest island, the air has literally the smell of a graveyard, and a feeling of nausea and heaviness comes over any one unaccustomed to imbibe the musty atmosphere. It is not only the nose, but the stomach, that tells how heavily the air is loaded with sulphuretted hydrogen; and as soon as you cross one of the crazy and rotting bridges over the reeking ditch, you know, as surely as if you had chemically tested it, by the black colour of what was once the white-lead paint upon the door-posts and window-sills, that the air is thickly charged with this deadly gas. The heavy bubbles which now and then rise up in the water show you whence at least a portion of the mephitic compound comes, while the open doorless privies that hang over the water side on one of the banks, and the dark streaks of filth down the walls where the drains from each house discharge themselves into the ditch on the opposite side, tell you how the pollution of the ditch is supplied.

  The scientific establishment was equally anchored in the miasma theory. In September 1849, the Times ran a series of articles that surveyed the existing theories about cholera: “How is the cholera generated?—how spread? what is its modus operandi on the human frame? These questions are in every mouth,” the paper observed, before taking a decidedly pessimistic stance on the question of whether they would ever be answered:

  These problems are, and will probably ever remain, among the inscrutable secrets of nature. They belong to a class of questions radically inaccessible to the human intelligence. What the forces are which generate phenomena we cannot tell. We know as little of the vital force itself as of the poison-forces which have the power to disturb or suppress it.

  Despite this bleak forecast, the Times went on to survey the prevailing theories: a “telluric theory that supposes the poison to be an emanation from the earth”; an “electric theory” based on atmopheric conditions; the ozonic theory that attributed outbreaks to a deficiency of ozone in the air; a theory that blamed cholera on “putrescent yeast, emanations of sewers, graveyards, etc.” The paper also mentioned a theory that maintained that the disease was spread by microscopic animalcules or fungi, though it downplayed its viability, claiming that the theory “failed to include all the observed phenomena.”

  The diversity of views is striking here—ozone, sewer emanations, electricity—but just as striking is the underlying commonality: all but one of the theories assume that the cholera is somehow being transmitted through the atmosphere. (Snow’s waterborne theory, already a matter of public record, goes completely unmentioned.) The a
ir was the key to the riddle of cholera, and indeed to most known diseases. Nowhere is the philosophy more pronounced than in the writings of the Victorian age’s most beloved and influential medical figure, Florence Nightingale. Consider this passage from the beginning of her groundbreaking 1857 work Notes on Nursing:

  The very first canon of nursing, the first and the last thing upon which a nurse’s attention must be fixed, the first essential to a patient, without which all the rest you can do for him is as nothing, with which I had almost said you may leave all the rest alone, is this: TO KEEP THE AIR HE BREATHES AS PURE AS THE EXTERNAL AIR, WITHOUT CHILLING HIM. Yet what is so little attended to? Even where it is thought of at all, the most extraordinary misconceptions reign about it. Even in admitting air into the patient’s room or ward, few people ever think, where that air comes from. It may come from a corridor into which other wards are ventilated, from a hall, always unaired, always full of the fumes of gas, dinner, of various kinds of mustiness; from an underground kitchen, sink, washhouse, water-closet, or even, as I myself have had sorrowful experience, from open sewers loaded with filth; and with this the patient’s room or ward is aired, as it is called—poisoned, it should rather be said.

  With Nightingale, the problem is one of emphasis; there’s obviously nothing wrong with ensuring that hospital rooms have fresh air in them. The problem arises when supplying clean air becomes the single most important task for the doctor or nurse, when the air is assumed to be a “poison” that has caused the patient’s illness in the first place. Nightingale believed that cholera, smallpox, measles, and scarlet fever were all miasmatic in nature, and she recommended that schools, homes, and hospitals use a certain “air test,” devised by the chemist Angus Smith, that detected organic materials in the air:

  If the tell-tale air test were to exhibit in the morning, both to nurses and patients, and to the superior officer going round, what the atmosphere has been during the night, I question if any greater security could be afforded against a recurrence of the misdemeanor.

  And oh, the crowded national school! where so many children’s epidemics have their origin, what a tale its air-test would tell! We should have parents saying, and saying rightly, “I will not send my child to that school, the air-test stands at ‘Horrid.’” And the dormitories of our great boarding schools! Scarlet fever would be no more ascribed to contagion, but to its right cause, the air-test standing at “Foul.”

  We should hear no longer of “Mysterious Dispensations,” and of “Plague and Pestilence,” being “in God’s hands,” when, so far as we know, He has put them into our own. The little air-test would both betray the cause of these “mysterious pestilences,” and call upon us to remedy it.

  So often what is lacking in many of these explanations and prescriptions is some measure of humility, some sense that the theory being put forward is still unproven. It’s not just that the authorities of the day were wrong about miasma; it’s the tenacious, unquestioning way they went about being wrong. An investigator looking for holes in the theory could find them everywhere, even in the writings of the miasmatists themselves. The canary in the miasma coal mine should have been the sewer-hunters, who spent their waking hours exposed to the most noxious—sometimes even explosive—air imaginable. And yet, bizarrely, the canary seemed to be doing just fine, and Mayhew admits as much in one slightly puzzled passage in London Labour and the London Poor:

  It might be supposed that the sewer-hunters (passing much of their time in the midst of the noisome vapours generated by the sewers, the odour of which, escaping upwards from the gratings in the streets, is dreaded and shunned by all as something pestilential) would exhibit in their pallid faces the unmistakable evidence of their unhealthy employment. But this is far from the fact. Strange to say, the sewer-hunters are strong, robust, and healthy men, generally florid in their complexion, while many of them know illness only by name. Some of the elder men, who head the gangs when exploring the sewers, are between 60 and 80 years of age, and have followed the employment during their whole lives.

  As Snow observed many times in his writings during the period, there were countless cases of groups sharing the exact same living environment, breathing the exact same air, who seemed to have entirely opposing responses to the allegedly poisonous vapors. If the miasma was truly killing off Londoners, it seemed to choose its victims in an entirely arbitrary fashion. And despite the fact that Chadwick and his commissions had made immense progress in eliminating the city’s population of cesspools, the cholera had nonetheless come roaring back to devastate the city in 1853.

  All of which begs the central question: Why was the miasma theory so persuasive? Why did so many brilliant minds cling to it, despite the mounting evidence that suggested it was false? This kind of question leads one to a kind of mirror-image version of intellectual history: not the history of breakthroughs and eureka moments, but instead the history of canards and false leads, the history of being wrong. Whenever smart people cling to an outlandishly incorrect idea despite substantial evidence to the contrary, something interesting is at work. In the case of miasma, that something involves a convergence of multiple forces, all coming together to prop up a theory that should have died out decades before. Some of those forces were ideological in nature, matters of social prejudice and convention. Some revolved around conceptual limitations, failures of imagination and analysis. Some involve the basic wiring of the human brain itself. Each on its own might not have been strong enough to persuade an entire public-health system to empty raw sewage into the Thames. But together they created a kind of perfect storm of error.

  MIASMA CERTAINLY HAD THE FORCE OF TRADITION ON ITS side. The word itself is a derivation from the Greek term for pollution; the notion of disease being transmitted by poisoned air dates back to Greek medicine of the third century B.C. Hippocrates was so obsessed with air-quality issues that his medical tracts sometimes sound like instructions for a novice meteorologist. His treatise On Air, Water, and Places begins: “Whoever wishes to investigate medicine properly, should proceed thus: in the first place to consider the seasons of the year, and what effects each of them produces for they are not at all alike, but differ much from themselves in regard to their changes. Then the winds, the hot and the cold, especially such as are common to all countries, and then such as are peculiar to each locality.” (Farr would echo this philosophy centuries later: his Weekly Returns would invariably include a brief weather report, before getting to the body count.) Just about every epidemic disease on record has been, at one point or another, attributed to poisoned miasma. The word “malaria” itself derives from the Italian mal aria, or “bad air.”

  Miasma theories were eminently compatible with religious tradition as well. As one might expect from a man of the cloth, Henry Whitehead believed that the Golden Square outbreak was God’s will, but he supplemented his theological explanation with a miasmatic one; he believed that “the atmosphere, all over the world, is at this time favourable to the production of a most formidable plague.” To reconcile this hideous reality with the idea of a beneficent Creator, Whitehead had settled on what might later have been termed an ingeniously Darwinian explanation: that plagues were God’s way of adapting the human body to global changes in the atmosphere, killing off thousands or millions, but in the process creating generations that could thrive in the new environment.

  But tradition alone can’t account for the predominance of the miasma theory. The Victorians who clung to it were in almost every other respect true revolutionaries, living in revolutionary times: Chadwick was inventing a whole new model for shaping public health; Farr transforming the use of statistics; Nightingale challenging countless received ideas about the role of women in professional life, as well as the practice of nursing. Dickens, Engels, Mayhew—these were not people naturally inclined to accept the status quo. In fact, they were all, in their separate ways, spoiling for a fight. So it’s not sufficient to blame their adherence to the miasma theory purely on its long
pedigree.

  The perseverance of miasma theory into the nineteenth century was as much a matter of instinct as it was intellectual tradition. Again and again in the literature of miasma, the argument is inextricably linked to the author’s visceral disgust at the smells of the city. The sense of smell is often described as the most primitive of the senses, provoking powerful feelings of lust or repulsion, triggering mémoires involontaires. (Proust’s original madeleine-inspired reverie was triggered largely by taste, but the power of smell alone is a recurring theme of In Search of Lost Time, and of course smell is an essential component of taste.) Modern brain-imaging technology has revealed the intimate physiological connection between the olfactory system and the brain’s emotional centers. In fact, the seat of many of those emotional centers—the limbic system—was once called the “rhinen-cephalon,” literally “nose-brain” or “smell-brain.” A 2003 study found that strong smells triggered activity in both the amygdala and the ventral insula. The amygdala is an evolutionarily ancient part of the brain, much older than the mammalian higher functions of the neo-cortex; raw instinctual responses to threats and emotionally charged stimuli emanate from the amygdala. The ventral insula appears to play an important role in biological urges, like hunger, thirst, and nausea, as well as in certain phobias. Both regions can be thought of as alarm centers of the brain; in humans, they possess the capacity to override the neocortical systems where language-based reasoning occurs. The brain scans in the 2003 study found that sharply unpleasant smells triggered disproportionately strong responses in both the amygdala and the ventral insula.