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A Most Insidious Poison Taking Advantage of Our Necessities: A Brief Historical Introduction to Lead and Lead Poisoning
Christian Warren
The Useful Metal
In the twentieth century, lead manufacturers occasionally promoted their product as âthe useful metal.â Orlando Harn, head of advertising for the National Lead Company, took that one step further. In 1924 Harn, who had created the Dutch Boy trademark for NLCâs famous white lead paint, published a book entitled Lead: The Precious Metal, a breezy compendium of the thousands of uses the modern world found for the element.1 No one should be surprised that Harnâs book barely acknowledged the toxicity of the lead in the Dutch Boyâs paint bucket. This book certainly does acknowledge that as long as we have exploited lead for its many applications in engineering, industry, and the arts, we have done so with some knowledge of its potential to poison us. This chapter provides a brief overview of both the promise and peril of Harnâs precious metal, and describes the gradual progress since the late eighteenth century toward fully recognizing its hazards, by means of several brisk but detailed vignettesââminiatures,â if you will (from âminiumââlead tetroxide, a favorite red pigment for centuries).
Leadâs physical characteristics go a long way toward explaining its indispensability. In its metallic form it is easily worked: its low melting temperature makes it easy to cast or use as a durable solder. Lead sheets are easy to bend, hammer, and joinâthe perfect material for conveying clean water into homes, and waste water away. The very word âplumbingâ derives from the Latin word for lead, plumbum. Leadâs weightâthe second densest elementâis an integral part of its identity and its utility. Its heft made it ideal for weapons, ballast, and standard measures. And for millennia, its many âusefulâ features made it an ideal lining for coffins.2
The Romans associated lead with Saturn, the slowest (heaviest) of the visible planets. Saturn was the father of the gods, and the Romans, like the Greeks and the ancient Chinese, believed from their experience with metallurgy that lead was the father of other metals. The identification continued in alchemy and astrology, and into modern era: well into the twentieth-century scientists and physicians referred to lead and its compounds as Saturn, or extracts of Saturn; âsaturnismâ or variants remain a term for lead poisoning in many languages.
As versatile as metallic lead is, the elementâs chemical properties make it even more so when compounded with other elements. Leadâs oxides come in a range of bright colors, with their own attractive set of attributes as pigments, coatings, and chemicals. Some of the most ancient ceramic glazes contain lead compounds, and most ceramics and porcelain contained a high percentage of lead carbonate or other oxides. Lead carbonate, or ceruse, has historically been the most commonly used. It is bright white, easy to manufacture, readily mixed in oil and applied on surfaces from canvas, metal, wood, and human skin. Ceruse was a popular face makeup from ancient Greece to Victorian England, for those who wanted to simulate the palest white complexion, though users risked serious toxic exposure. Ceruse was not the first leaden cosmetic, though. Decorating the eyes with kohl, essentially finely ground galena ore, predates the technology to smelt metallic lead. Kohl has been a popular eye makeup since Ancient Egypt and is still widely used in the Middle East and South Asia. Lead compounds colored all manner of cosmetics, from hair dyes to lipstick.3
The most ironic uses for lead and lead compounds have been its many applications in health and medicine. Bernardino Ramazzini, a seventeenth-century pioneer in occupational medicine, called lead âthe surgeonâs mainstay.â Saturnine compounds filled medicine chests from ancient times to the twentieth century. Spanish explorers to the Americas brought lead plasters and ointments to treat any number of conditions. Those sailors and soldiers who went home from the New World afflicted with syphilis might have had their ânewâ disease treated with leaded ointments. Lead compounds have been used since antiquity to control fertility. Aristotle recommended applying white lead ointment to the cervix to prevent pregnancy. Plentiful examples of nineteenth-century newspaper advertisements for lead-containing abortifacients attest to widespread belief in leadâs effectiveness when contraception failed. Basic awareness of leadâs toxic effects is also ancient: in the second century BCE, the Greek poet and physician Nicander described most of the classic symptoms of saturnismâincluding hallucinations and paralysis. Physicians have long noted the contradiction of leadâs toxicity and their reliance upon leaden compounds. Ramazzini thought it strange that lead, the âsurgeonâs mainstay,â was âso deadly that potters who need its aid are thus stricken.â4
If we always knew of leadâs toxicity, our understanding of just how it affects the body has evolved over the centuries. Lead begins attacking the body when it is absorbed into the bloodstream, most often from the intestines or lungs. Most of this blood-borne lead is distributed to the bones, which absorb the lead ions as if they were useful minerals. Bound up in the matrix of the bones, for a time it poses little direct threat. However, months or years after exposure, this sequestered lead can leach back into the blood stream to resume its attack on soft tissues: kidneys, reproductive organs, andâmost criticallyâthe nervous system.
Clinicians describe a given case of lead poisoning along two axes: one ranging from âchronicâ to âacute,â depending on the abruptness with which symptoms appear and their duration; the other along the axis between âclinicalâ and âsubclinical,â referring to the severity of the poisoning, with âsubclinical,â or âasymptomaticâ describing cases where measurable damage from lead evokes no outward symptoms, while âclinicalâ refers to symptoms that a trained clinician could observe directly. These symptoms range from mild fatigue and sleeplessness to weakness, abdominal pain, constipation, persistent vomiting, and to clumsiness, extreme dizziness, and other signs of nerve damage, including paralysis of limbs to convulsions and swelling of the brain (lead encephalopathy) that was almost always fatal in the years before the development of effective de-leading treatments.
The era of effective treatments for lead poisoning came with improved diagnostic tools. In turn, this new set of tools shifted the focus of both medical and regulatory action on lead. Prior to the 1950s, clinicians and regulators concentrated on acute, severe lead poisoning: workers hospitalized with acute abdominal complaints (often called by trade-related names: âpainterâs colicâ or âpotterâs colicâ) or peripheral paralysis (âwrist dropâ commonly in painters, âankle dropâ in potters); children brought to emergency rooms with crippling colic, or in the throes of lead encephalopathy. With the advent of powerful chelating drugs and more accurate screening and diagnostic tools, and with the easing of lead poisoningâs relentless mortality, the focus has shifted to prevention of what was once called âlow-levelâ lead exposure.
This pattern of discovery, response, and rediscovery (or re-definition) charts a halting trajectory. It is a narrative of discovery and progress and fallbackânot exactly Sisyphean, but often perceived as such by contemporary observers. Benjamin Franklin famously lamented, âhow long a useful truth may be known and exist, before it is generally received and practiced on.â5 Our knowledge is always imperfect, and our willingness to âpractice onâ that knowledge more so.
Lead in the Enlightenment
Franklin made that oft-quoted observation in a letter to his friend Benjamin Vaughan, a young British physician and politician. Vaughan had asked Franklin, eighty, to jot down all he âcould recollect on the subject.â After a long life as an inventor and correspondent with scientists and medical men on both sides of the Atlantic, Franklin had a lot to recollectâabout leadâs indispensability in technology and the arts, and about its deadliness. Franklin recalled a story from his teenage years when he worked as a typesetter. Bent over their printing forms, often in poorly ventilated shops, typesetters could hardly help breathing and swallowing particles of lead from the type, and many became seriously lead poisoned after years of exposure, suffering painful stomach aches, or, worse, âthe danglesââparalysis of their hands. The young Franklin developed symptoms suggestive of a dangerous chronic exposure, symptoms he described as âa kind of obscure Pain that I had sometimes felt as it were in the Bones of my Hand.â6
As bad as lead exposure was in typical print shops, other lead-using trades were far worse. Medical studies from the late seventeenth century on found that industrial work in lead smelters, paint factories, and potteries was deadly.7 Similar dangers lurked in the studios of glass blowers, stained glass artists, potters, and painters, who relied heavily on lead carbonate (with innocuous names like âflake white,â âBerlin white,â and âsilver whiteâ) and colorful lead pigments, from chrome yellow to bright red minium. Franklin had the opportunity in 1767, when visiting Paris with John Pringle (soon to be appointed as personal physician to King George III), to read a report from HĂŽpital de la CharitĂ©, which Franklin noted was âparticularly famousâ for its cure for lead poisoning. Almost all of the hospitalâs lead patients had worked as plumbers, glaziers, painters, or paint grinders in factories. Decades later, Parisian physician Tanquerel des Planches studied La CharitĂ©âs enormous population of lead-poisoned workers for his groundbreaking 1839 study, TraitĂ© des Maladies de Plomb ou Saturnines.8
Lead-tainted alcohol was the second most-studied vector for lead poisoning before the twentieth centuryâand with good reason: it is likely that up to that time, lead-adulterated beverages poisoned more people than any other non-occupational source. The first wine adulteration was probably inadvertent, through contamination during storage, or as a result of boiling sweeteners and flavorants in leaden vessels, but experience and experimentation led distillers and vintners to use lead to control fermentation or alter the taste of their products. These toxic shortcuts did not go unnoticed, though efforts to regulate them seem to have had little effect. Charlemagne is reputed to have banned leaded wines in 802 CE. By the eighteenth century wine-related lead poisoning prompted harsh countermeasures: harsh fines, imprisonment, or even death awaited convicted wine adulterers.9 Regardless, sporadic epidemics of lead poisoning from adulterated alcohol continued, often taking the name of the town or region where they originated: the Colic of Poitou, named for a 1639 epidemic of severe colic in the French town of Poitiers, in the district of Poitou, became a generic term (often Latinized as colica pictonum) for lead poisoning. A doctor described the victims in Poitou as appearing âjust like ghosts or statues ⊠walking artificially, pallid, squalid, lean, with their hands crooked and hanging under their own weight.â10 Other notable examples include the Madrid Colic, the Colic of Normandy, andâmost famouslyâthe Devonshire Colic.
Apple cider production was a big business in the shire of Devon in the 1700s, with nearly every farm producing hard cider for the market. Devonians themselves drank tremendous quantities, and for most of the century, their drink of choice made many of them sick. Devonshire physician George Baker compared stricken Devonians to those zombie-like sufferers from Poitou.11 In 1767, Baker tested Devonshire cider, using some of the techniques developed by alchemists centuries before, and found it was heavily leaded. Bakerâs investigations showed that lead entered Devonshire cider accidentally at many stages of production. On top of that, many farmers and merchants added white lead directly to the cider to correct acidity or to check fermentation. The regionâs cider producers dismissed all this, insisting that the only lead to be found in Devonshire cider came from the lead-shot farmers used to shoot birds dining from apple piles!
Baker initially relied on the published study on the Colic of Poitou, but he also consulted with Benjamin Franklin, like Baker a Fellow of the Royal Society, and visiting London when Baker was undertaking his study. Franklin noted that the symptoms in Devonshire were identical to those in an epidemic in the American colonies forty years earlier, caused by the use of lead pipes in some Massachusetts rum distilleries. In 1723, the colony outlawed lead in rum stills, and the disease all but disappeared. In the decades after Bakerâs research, the annual visitations of Devonshire colic gradually abated, although it is an open question how much credit is due Baker, who was elevated in medical history myth as singlehandedly ending the scourge, but whose reputation in Devonshire would seem to undercut his influence on cider producers.12
Given Franklinâs lifelong interest in lead poisoning, it is highly ironic that he likely suffered in old age from one of its most insidious forms, as a lifetimeâs burden of lead absorbed through his work, research, and leisurely drinking poisoned his soft tissues. From his late middle age, Franklin suffered from gout, a painful swelling of the joints, especially in the lower legs and feet. Franklinâs gout caused him considerable pain, but he bore it with his usual good humor, even publishin...