In the summer of 1796 Edward Jenner worked a small quantity of pus extracted from the sores of a cowpox-infected dairymaid into a pair of incisions on the arm of James Phipps, aged eight. As Jenner tells it in his 1798 treatise, An Inquiry into the Causes and Effects of the Variolae Vaccinae, this crude injection soon ran its course: on the seventh day the boy suffered a slight headache and a loss of appetite but on the following day was in good health. More surprising was that the boy was found to be immune to smallpox after the procedure: two months later, when Jenner introduced the far deadlier variola virus under the boy’s skin, “no sensible effect was produced.” The local inflammation and fevered delirium that normally followed inoculation were absent, a sign of Phipps’s enduring immunity.

Jenner wasn’t aware of the pathogenic cause of the new inoculant’s success — the cowpox (variola vaccinia) and smallpox (variola major) viruses are genetic kin, distinct but similar enough to ensure that exposure to the former induces immunity to the latter — but he was familiar with its effect: “Morbid matter of various kinds, when absorbed into the system, may produce effects in some degree similar,” he wrote,“but what renders the Cow-pox virus so extremely singular, is, that the person who has been thus affected is for ever after secure from the infection of the Small Pox […].”

True to its name, Jenner’s Inquiry forms a catalogue of notes that sets out Jenner’s findings in sequentially numbered cases. “In support of so extraordinary a fact,” Jenner explains in the work’s preface, after laying out his hypothesis, “I shall lay before my Reader a great number of instances.” Of course, Jenner’s “instances” are human beings, and the Inquiry is populated by a faceless cross section of Jenner’s rural society, from an aging under gardener to a “respectable Gentlewoman” identified only as Mrs. H——, disguised by an elongated dash in deference to her station.

Insofar as the Inquiry’s experiments emerged organically from Jenner’s provincial setting, he owed much to the homespun learning of his neighbors. As Eula Biss remarks in her 2014 book On Immunity, Jenner’s coinage of a new Latinate disease (varoliae vaccinae, literally ‘smallpox of the cow’) belies the humble origins of vaccination: “Its roots are in folk medicine,” she writes, “and its first practitioners were farmers.” This folk knowledge is still with us, distilled into aphorism: Something is said to be “as smooth as a milk maid’s skin.” More than mere hyperbole, this phrase encodes centuries of unlettered medical learning and observation. When the early modern world suffered under smallpox and its 30% mortality rate, the dairymaid was held to be a preternatural creature unmarred by the virus’s disfiguring traces. What Jenner’s Inquiry showed is that the fabled immunity (if not the complexion) of milkmaids could be artificially imparted.

Many of Jenner’s case notes are paired with disquietingly beautiful illustrations that depict pox sores and pustules in various states of suppuration. One such image shows the lithe hand of Sarah Nelmes, a milkmaid who had contracted cowpox through a small scratch on her right hand while tending her bovine charges. Jenner’s written observations on Nelmes’s hand couch anatomy in the winsome language of fairy tale, hinting at a poetics of vaccination: “She received the infection on a part of the hand which had been previously in a slight degree injured by a scratch from a thorn.” From a cow’s infected dug through an accidental cut on an unprotected finger, Jenner traces the disease’s progress through brambles, fields, and barnyards. To speak of herd immunity, then, is to use a dead metaphor with roots in 18th-century pastoral. Vaccination (vacca, Latin for ‘cow’) and the almost magical prophylaxis it accords originated in, strange to say, a herd of cattle.

Bucolic imagery imbues the lexicon of western medicine,and Jenner’s cow-cure is no exception. The phrase “herd immunity” itself, though of a later date than Jenner’s vaccine, also relies on agrarian metaphors: Herd immunity works by a kind of collective insulation, where the weaker few are protected by the vaccinated or antibody-bearing many — much like, for instance, a herd of ruminants shielding its youngest and weakest from predators and privation. But if vaccine is the product of the pastoral, inoculation stems from the georgic, borrowed from the routine labors of arborists in orchards. “To inoculate” means to graft, an image that recalls both the insertion of foreign matter into an unwilling (or at least indifferent) host and the botanical suture and symbiosis that follow. Not by chance, perhaps, Jenner ran a vaccination clinic from a thatch-roof folly built among the plantings and paths of his suburban garden in Berkeley, Gloucestershire. He named this structure the Temple of Vaccinia and offered from its single room his new vaccine pro bono to the poor of the district. Vaccination has its own strange mythos, then, with Jenner as a kind of benevolent Lancer of the Glen. 

Artist unknown, “The vaccinated arm of William Summers, eight years old” (1798), hand-colored engraving on paper, 244 x 207 mm 

Far though we’ve come from Jenner’s horticultural clinic, his experimental dermal lancings are relevant again — all the more so, given that one of the vaccines for the COVID-19 virus was developed at the Jenner Institute in Oxford, UK. Jenner’s name has become a word with cultural weight and authority, and we expect an institute bearing that name to provide therapeutic deliverance. Despite Jenner’s posthumous reputation among epidemiologists and medical historians, though, the history of vaccination resists being pigeonholed into categories that structure the history of science. Vaccines are not, as we might expect, a pure invention of western ingenuity, institutes, or formal experimentation. A form of immunization against smallpox known as variolation had been performed in China, Africa, and West Asia as early as the 16th century. This procedure involved inserting a sample of live smallpox (again in the form of carefully harvested pus) under a patient’s skin. This method of deliberate infection was hazardous, occasionally leading to the death of the inoculated or occasioning new epidemics. Insufflation, another method of immunization practiced in early modern China, involved forcefully blowing pulverized smallpox scabs into a patient’s nasal cavity — with searing results, no doubt. Jenner’s method was not new, then, but it was groundbreaking, both for its harmlessness and its quotidian source: a cow named Blossom.

Jenner’s illustrations were similarly groundbreaking. The sores that adorn Jenner’s renderings of afflicted arms and hands are colored in mucid tones of ecru and green, each pitted ulcer haloed by a daubed corona of faded pink. Jenner describes these dermic signs as “superficial suppurations” that “put on a circular form, with their edges more elevated than their centre.” Obscured by the immediacy of these illustrations is the fact that they are composites: “the pustule on the fore finger,” Jenner notes of the illustration of Nelmes’ hand, “shews the disease in an earlier stage. It did not actually appear on the hand of this young woman, but was taken from that of another, and is annexed for the purpose of representing the malady after it has newly appeared”.

Each of the illustrations that accompanies Jenner’s case studies was first engraved in copperplate and printed on an intaglio press in a sanguine shade of ink. But the sores themselves were finished by hand in watercolors after printing, making every copy of Jenner’s Inquiry a unique artifact and work of art. The effect of the engravings’ hybrid medium is startling, conveying a realism usually unobtainable in printed anatomical illustrations of the period and offering welcome clarity in the face of Jenner’s vacillating prose: the sores are sometimes “palish blue, or rather of a colour somewhat approaching to livid,” Jenner says. Ekphrasis fails where images enthrall.

Artist unknown, “The vaccinated arm of John Baker, five years old” (1798), hand-colored engraving on paper, 244 x 207 mm 

Jenner’s grisly illustrations of misbehaving skin are as much instruments of comfort, then, as they are graphic records of therapeutic intervention: The accurate portrayal of the disease’s defining attribute — the sores or “pocks” that give poxes their name — makes Jenner’s text useful for visual diagnosis and subsequent treatment. Georgian doctors and amateur vaccinators could consult Jenner’s Inquiry to guide the successful vaccination of their own patients, for instance. But Jenner’s images also encourage his readers to view the sores they depict as positive symptoms, as signs imputing budding immunity and recovery rather than impending crisis.

In other words, Jenner’s illustrations offered beauty and quietus of a clinical kind, anticipating a genre of image we now recognize as detached, austere, diagnostic — the pictorial stuff of WebMD and anatomy textbooks. We seek out depictions of disease not from morbid fascination with illness and disfigurement, but in an effort to humanize both. Harvard historian of art Sarah Lewis recently observed that the rapid spread of COVID-19 is uniquely disorienting because news reports lack images of the dead, diseased, and dying. What’s more, there is scant visual evidence of the virus’s horrific effects; it is a disease that injures from within, slowly draining its victims of breath. We have instead been fed data and models that predict the virus’s grim progress through a population of anonymous victims. When we did catch glimpses of the COVID-dead, they were shrouded in sealed body bags, stacked in makeshift morgues parked unceremoniously in the loading docks of hospitals.

Disease maps operate at a still further remove. Broadcast with the evening news, these maps depict regional micro-epidemics, like clouds passing over the contours of familiar geographies. An animated graphic released on social media by the British Consulate in the US showed earth from space, our pale blue dot grotesquely transformed into the COVID-19 virus, its corona of monstrous spikes extruding through erstwhile atmosphere. While these infographics and diagrams imply death, they mask its realities — that the virus’s victims are known to many of us, for instance. By contrast, forthright images of disease, Sarah Lewis writes, “can help us more deeply understand the severity of the situation as we work to curb the virus. […] They help us humanize clinical statistics, to make them comprehensible. They step unto the breach.” With the terror of smallpox faded from our collective memory, it is easy to forget that Jenner’s illustrations would have served this function for an audience trained to view pox sores as signatures of death or disfigurement. This explains their strange and unsettling beauty. They are pockmarked harbingers of hope.

Artist unknown, “The vaccinated arm of Hannah Excell, seven years old” (1798), hand-colored engraving on paper, 244 x 207 mm 

Anxious to see these reassuring signs,some of Jenner’s patients worried about the new vaccine’s potency. The earlier form of inoculation, variolation, was often the cause of handwringing when it failed to incite an attenuated form of smallpox: “There are many, who from some peculiarity in the habit resist the common effects of variolous matter inserted into the skin, and who are in consequence haunted through life with the distressing idea of being insecure from subsequent infection.” Jenner proposes his new method as a reassuring alternative: “A ready mode of dissipating anxiety originating from such a cause must now appear obvious.” Jenner’s cowpox vaccine, unlike other forms of inoculation, never failed to give coincident rise to oracular pustules and a fevered crisis. Its potency was authenticated and effected by physical trial. Modern vaccines are instead expected to work their wizardry surreptitiously: They bestow immunity (or ought to) without dermic eruptions or foreboding symptoms. Perhaps this expectation accounts, in part, for the obduracy of antivax sentiment. There is something innate in us that distrusts treatments that lack noxious stimulus or disfiguring effect. The idea of drinking bleach as a curative, for instance, holds our fascination for its unsophisticated violence. Cytotoxicity is the therapeutic preserve of the desperate: We poison ourselves, hoping that the disease falters and abates before we do.

Jenner viewed vaccination as a way to restore balance to humankind’s native immunity. In his preface to the Inquiry, he ascribes the 18th century’s proliferation of diseases to “[t]he deviation of Man from the state in which he was originally placed by Nature.” The precarity of our health, Jenner’s words suggest, is a product of our withdrawal from the natural world and its perceived benefits, benefits which vaccination might re-inject through fragile skin. This is an odd doctrine to modern ears accustomed to dubious litanies of pharmaceutical ingredients whose botanical origins are obscured behind chemical nomenclature. Of course, Jenner’s position was colored by a bucolic idyll in which he imagined milkmaids and cattle took willing part — Blossom, the brown dairy cow said to harbor the first case of cowpox used in Jenner’s experiments, was later flayed, her hide mounted and displayed in the halls of St. George’s Hospital, London. Still, his attitude is remarkably modern. Notwithstanding recent and persistent disinformation that seeks to portray vaccines as unnatural and transgressive, the optimism of vaccination’s earliest proponent comes as some surprise: “I shall myself continue to prosecute this inquiry,” Jenner writes on the Inquiry’s final page, “encouraged by the hope of its becoming essentially beneficial to mankind.” Encountering these words and revisiting Jenner’s book 223 years after their publication remind us of the tenuous nature of wellness and the fraught course by which progress in medicine is won: The last recorded case of smallpox was diagnosed in 1977, and it wasn’t until 1980 that the World Health Organization announced the disease’s final, fateful eradication. As vaccination rates lag globally, let us hope that COVID-19 proves to be of shorter duration.

Sam Lemley is the Curator of Special Collections at Carnegie Mellon University Libraries.