The recipe for animal sacrifice in ancient Greece

By Flint Dibble

We’re so used to modern, twenty-first century recipes. Everything is spelled out to a tee: ingredients, amounts, instructions. But, even if you look at earlier 20th century recipes, the detail is sparser. Techniques and amounts could be optional or elided over since certain knowledge was assumed. Ancient recipes, like those by the Roman chef Apicius, are even worse. There’s so much assumed knowledge, and we’re at such a cultural distance that it’s difficult to know exactly how a meal was prepared (though that doesn’t stop us from trying).

The recent online trend in recipes is recipe-blogging. For these, the detail can be excruciating. You need to read (or scroll) through a personal story about the recipe to get to the ingredients, amounts, and process. Understanding ancient Greek food from literary sources is like having access to the story part of a recipe-blog, without the recipe itself.

The recipe for animal sacrifice in ancient Greece is deceivingly simple: wrap a few bones in fat and burn them to a crisp. But, like many ancient recipes, the closer you examine it, the more questions you have. When you put together all our sources of evidence for ancient sacrifice – literary texts, artistic depictions, and ancient animal bones – the variability in ancient practice refreshes old research angles.

The epic poet Hesiod first described the reasons behind ancient animal sacrifice in a story about Prometheus tricking Zeus. Having chopped up an ox, he arranged two portions: 1) for mortals, Prometheus assigned the meat stuffed in the unappetizing stomach, and 2) while Zeus chose the white bones hidden beneath delicious, glistening fat. Hesiod ends this tale of deception with the offhand comment that ever since then, people have burned white bones for the gods (Hesiod Theogony 557).

But animal sacrifice was everywhere in ancient Greece. At every twist and turn of the story, Homeric heroes sacrificed mythical herds of big, beautiful bulls. In Book 3 of the Odyssey, the sacrificial recipe for a cow at the Palace of Nestor at Pylos is described in epic detail. After it was struck with an ax, and its blood collected in a bowl:

They butchered her, cut out the thighs, all in the proper place, and covered them with double fat and placed raw flesh upon them. The old king burned the pieces on the logs, and poured the bright red wine. The young men came to stand beside him holding five-pronged forks. They burned the thigh-bones thoroughly and tasted the entrails, then carved up the rest and skewered the meat on pointed spits, and roasted it (translation from Wilson 2017).

This scene is an exception. Most of the time, the gory details of sacrifice were assumed knowledge. That said, when mentioned, most often, the thigh-bones were mentioned as burned for the gods.

There are only a few exceptions to this pattern of thigh-bone burning in ancient Greek literature. In Aristophanes’ comedic play Peace (1055), the protagonist notes, after burning the thigh-bones of a sacrificed sheep, that the tail is curling. Scholars have connected this line with the many scenes of sacrificial curling tails painted on Athenian pots. Without this iconographic evidence, we wouldn’t have a clear context for this enigmatic mention in literature.

Pottery: red-figured stamnos depicting a an altar on a double plinth, on which two rows of sticks set crosswise, are burning, with a large hook or the horn of an ox and a square object in the midst of the flames; beside it stands a bearded, wreathed man, in a mantle, inscribed.
Athenian red-figure stamnos depicting a tail curling on a flaming altar (British Museum 1839,0214.68 CC BY-NC-SA 4.0).

A second exception is in the epic myth, the Homeric Hymn to Hermes (115-137). Hermes steals a herd of cattle from Apollo, and – to avoid being tracked – he marches them backwards to a cave. Wanting to make it up to the other gods, Hermes slaughters two of the cattle and distributes the meat into 12 portions. Cleaning up the mess, he burns the feet and heads of the cattle in the fire.

This scene is troublesome. There are no parallels in the artistic or literary record. To some scholars of ancient Greek religion, this is an inversion of a typical sacrifice. A literary construct of sorts. After all, the gods here were assigned the meaty human portion. Everything’s mixed up.

But this whole picture is turned on its head when you look at ancient trash: the food remains found in archaeological sites. For a long time, bits of animal bone were ignored in favor of the study of monumental temples or beautiful art. As a zooarchaeologist, I can tell you that when you start looking at ancient trash, the whole picture of ancient Greek animal sacrifice gets messy.

On the one hand, animal bone evidence does somewhat match patterns from literature and art. Most of our burned bones at sanctuaries and temples were thigh-bones. At a few temples, we even have examples of burned tails. More surprisingly, recent evidence shows several sites where the feet (and sometimes heads) of animals were burned. Maybe that scene in the Hymn to Hermes reveals actual ritual practice and not a literary inversion. 

Burned ankle joint
Burned ankle joint from Azoria, Crete. Photography by Jonida Martini.
Feet bones of sheep and goat.
Feet bones of sheep and goats from Azoria, Crete. Photograph by Jonida Martini.

On the other hand, the evidence is also more complicated. Most of the animal bones from ancient Greek sites aren’t burned, including many unburned thigh-bones found in many settlements. Whether this means most animals weren’t sacrificed or that some sacrifices didn’t involve bone burning is unclear.

Plus, even among a pit of burned bones, most of which match one of the patterns above, there are large numbers of exceptions: other anatomical parts that were burned. For example, bones in archaeological deposits from the Palace of Nestor at Pylos do provide evidence for the burning of cattle thigh-bones in feasting contexts, but burned in equal numbers were the jaws and upper-forelimbs (humerus).

The variability presented by this new source of evidence alongside the ambiguities of assumed knowledge means that we need to re-evaluate our evidence. While the burgeoning study of food trash won’t let us recreate all the details of a recipe, it’s an opportunity for us to look upon recipes in old texts with fresh eyes.


Flint Dibble is a Marie Skłodowska-Curie Research Fellow in the School of History, Archaeology, and Religion at Cardiff University. His project ZOOCRETE will be examining the role of animals and foodways in ancient Greece, with a specific focus on Crete. His research touches on topics of urbanism, climate change, religious ritual, and everyday life. Flint is also a public scholar with a strong commitment to sharing knowledge widely. He is active on Twitter (@FlintDibble) where he regularly writes Twitter threads with footnotes that present archaeology to the broader public.  

Conference Report: Traditions of Materia Medica: 300BCE–1300CE

By Sean Coughlin

On 16–18 June 2021, members of the research group A03 at the DFG-funded SFB 980 ‘Episteme in Motion’ and the Institute of Classical Philology, Humboldt-Universität in Berlin (Sean Coughlin, Christine Salazar, Lisa Sherbakova, Kristiane Hasselmann, Philip van der Eijk) held a conference called Traditions of Materia Medica: 300 BCE–1300CE. Over the three days, 25 speakers and over 50 guests from around the world met remotely to share research on the history of theoretical pharmacology in the immediate vicinity of Galen of Pergamum.

One goal for the conference was practical: to bring each other up to speed on what we’ve been doing since the start of the pandemic. Another was programmatic: to test the hypothesis that Galen’s writings on pharmacology constitute a key moment in the history of theoretical pharmacology, one that brought about an acceleration of pharmacological research and reflection. Speakers explored the hypothesis from the perspective of history of medicine, philosophy and science, Egyptology, philology, botany, chemistry and lexicography, focusing on Galen’s sources, his own work, and the work of those who followed him.

Image courtesy of Sean Coughlin

Galen’s Immediate Predecessors (3rd c. BCE – 2nd c. CE)

Among studies of Galen’s immediate predecessors, we heard from edition and translation projects that are bringing Galen’s pharmacological antecedents more clearly into view. David Leith (Exeter), working on the fragments of Asclepiades of Bithynia, presented part of his work into the pharmacology of Asclepiades and his school, many of whom, like Julius Bassus and Niger, were authorities for Dioscorides and Galen. Irene Calà (LMU Munich), critically editing books 10 and 14 of Aetius of Amida’s Medical Books, presented recently identified fragments of recipes from the Herophileans, Andreas of Carystus and Apollonius Mys. Costanza de Martino (Humboldt) discussed the structure and sources of Philumenus’ On Poisonous Animals and Their Remedies, part of her project producing a new edition, translation and study of this work. And Amber Jacob (NYU) presented her project editing 1st–2nd c. CE demotic medical papyri from the Tebtunis temple library, which represent some of the few surviving sources for Egyptian medicine of the period and the intercultural exchange of Greek and Egyptian pharmacology.

Galen of Pergamum (mid-2nd – early 3rd c. CE)

We also had presentations from edition and translation projects of Galen’s pharmacological works. Caroline Petit (Warwick) introduced methodological questions raised by her work on “Rethinking Ancient Pharmacology” and her edition of Galen’s treatise On Simple Drugs (Simples), which draws on Greek, Syriac, Arabic and Latin traditions. Caterina Manco (Paul Valéry – Montpellier) presented a study of Galen as reader of Dioscorides based on her forthcoming edition, translation and study of the botanical books of Galen’s Simples, books 6–8. And John Wilkins (Exeter) presented a comparative study of the ‘theoretical books’ (books 1–5) of Galen’s Simples, which he is translating for the Cambridge Galen Series, and their implementation in the ‘catalogue books’ (books 6–11).

Work on the history and philosophy of pharmacology was presented by P. N. Singer (Einstein Centre Chronoi), who discussed his work on epistemological and metaphysical issues raised by Galen’s notions of ‘changes through the whole substance’ and ‘tests’ of drugs. Simone Mucci (Warwick) presented on the relationship between imperial head-physicians (ἀρχιατροί) and antidotes in the Hellenistic and Imperial periods via Galen’s On Antidotes. And Krzysztof Jagusiak and Konrad Tadajczyk (Łódź) compared sitz-baths (ἐγκάθισμα) remedies in Galen’s work on Compound Drugs According to Kinds and in the pseudo-Galenica.

There were also two fascinating diachronic studies. Laurence Totelin (Cardiff) explored the nature, subject and variety of works called Euporista (“easily procured substances”) from their origins in Apollonius Mys via Galen to Theodorus Priscianus (4th c. CE). And Alessia Guardasole (CNRS – Sorbonne Université), who is working on an edition of Galen’s Compound Drugs According to Places, demonstrated how recipes change over time using the example of the diacodyon (διὰ κωδυῶν, “prepared with poppies”), from Galen to Theophanes Chrysobalantes (10th c. CE)

Galen’s Descendants (3rd – 13th c. CE)

Among scholars working on pharmacology after Galen, Petros Bouras-Vallianatos (Edinburgh) presented his work contextualizing ingredients from Asia in Galen, Late Antique and Byzantine medical works, exploring the reception of Arabic pharmacological lore into Greek and Latin sources. Anne Grons (Philipps-Universität Marburg) presented work on the systematization of ingredients in medical recipes preserved in Coptic pharmacological texts from the 4th–11th c. CE.

Matteo Martelli (Bologna) explored dry medicines, dyes, and alchemical xeria via the etymology of the term elixir, beginning with Arabic and Latin traditions and taking us back to their antecedents in Greco-Egyptian alchemy. Maciej Kokoszko (Łódź) looked at recipes for sweet sauces from Anthimus’ On the Observance of Foods and their pharmacological roots. Zofia Rzeźnicka(Łódź) proposed a theoretical basis for the ingredients of several recipes for peelings and scrubs in Aetius of Amida. And Lucia Raggetti (Bologna) discussed the creative weaving of ancient pharmacological, medical, and philosophical works (Hermes, Galen, Dioscorides, Aristotle) with technical and artisanal knowledge in Malmuk, Cairo of the 7th H/13th CE in the work of Kaylak Qabǧāqī.

Experimental, Lexicographical and Botanical Approaches

We also heard from several groups taking broadly empirical approaches to the history of pharmacology. On the chemical and biochemical side, Manuela Marai (Warwick) presented her work comparing the activity of drug combinations found in Galenic recipes to that of the individual components. Effie Photos-Jones (Glasgow) presented surprising results from the experimental work of her Wellcome Trust-funded group, “Greco-Roman Antimicrobial Minerals,” on the chemical and biological activity of Greco-Roman mineral preparations (lithargyros, psimythion, molybdos). Members of the ERC-project Alchemeast at Bologna, Matteo Martelli and Lucia Raggetti, included their work on replications of ancient alchemical recipes. And Sean Coughlin(Humboldt, Czech Academy of Sciences) introduced a new interdisciplinary research group funded by the Czech Science Foundation, “Alchemies of Scent,” that will replicate the methods of Greco-Egyptian perfumery using analytical chemistry and Greco-Egyptian literary and archaeological sources.

On the botanical and lexicographical side, Maximilian Haars (Philipps-Universität Marburg) gave an overview of his new DFG-funded project producing an encyclopedia of all medicinal plants and herbal drugs in the Galenic corpus—approximately 1,500 entries. And Barbara Zipser (Royal Holloway University London) and Andreas Lardos (Zurich) presented a new interdisciplinary methodology from their project “Plants and minerals in Byzantine popular pharmacy: a new multidisciplinary approach” for the identification of medicinal plants that can provide a more solid and replicable starting point for pharmacological screening.

Hopefully, this brief overview conveys some sense of the variety of research projects exploring Galenic pharmacology and its immediate predecessors and descendants. For those interested, abstracts for the talks are available here.

Interview with the Editors: The Cultural History of Medicine

By Elaine Leong, Lisa Smith and Laurence Totelin

The Cultural History of Medicine, a six-volume collection under the direction of Roger Cooter, was published in April 2021 by Bloomsbury. The editors of three of its volumes happen to be past or present editors of The Recipes Project: Laurence Totelin edited volume 1 (A Cultural History of Medicine in Antiquity, 500 BCE–800 CE); Elaine Leong co-edited volume 3 with Claudia Stein (A Cultural History of Medicine in the Renaissance, 1450–1650); and Lisa Smith edited volume 4 (A Cultural History of Medicine in the Age of Enlightenment, 1650–1800). Each volume follows the same structure: an introduction, followed by chapters on Environment; Food; Disease; Animals; Objects; Experiences; the Mind/Brain; and Authority. In this post, Elaine, Laurence and Lisa share their experience of participating in the project, and discuss what the reader of The Recipes Project will find of interest in the volumes.

Photo of six books standing up. The books are the six volumes of the Bloomsbury Cultural History of Medicine series.
The Cultural History of Medicine. Reproduced with the permission of Bloomsbury.

What attracted you to this project?

Laurence: I had already contributed to one of the other Cultural Histories, the Cultural History of Women with a chapter co-authored with Steven Muir on ‘Medicine and Disease’. I enjoyed the format and the potential that the volumes have for teaching. So when Roger Cooter contacted me and told me about his list of chosen topics for A Cultural History of Medicine, I could not refuse. I was delighted when I heard that Elaine and Lisa would also be editors.

Lisa: Like Laurence, I loved the idea of a series on the cultural history of medicine; it seemed the right moment for delving into the topic, as the field had slowly become more cultural – taking into consideration emotions, materiality, and more. The list of topics that Roger had chosen reflected these wider concerns, including – for example – environment. It struck me that there was a lot of scope for authors to play with these themes in interesting ways, which would appeal to students and colleagues alike.

Elaine: Like Laurence and Lisa, I felt like it was the right historiographical moment to bring together such a series. I also really welcomed the opportunity to work with my co-editor Claudia Stein and the series editor Roger Cooter. As I was working in a research institute at the time, I jumped at the chance to reflect upon pedagogy with an amazing group of scholars. The authors for the ‘Renaissance’ volume met up in 2016 and it was just wonderful to spend two days discussing the various strategies we use to teach histories of early modern medicine and health, and to collaboratively create teaching materials designed for the modern classroom.

Was your experience as an editor of The Recipes Project helpful in any way when editing your volume of A Cultural History of Medicine?

Lisa: My experience on the blog gave me a lot of experience in working with authors to make their work really readable to non-academics, which I hope will appeal (especially) to students. It also made me realise just how much I enjoy writing with others. Historians still typically work alone, but over the past decade, I’ve been increasingly involved in collaborative projects of which the Cultural History of Medicine is one. In fact, collaborative work is something that helped me through the pandemic! Co-writing with others and editing (the Recipes Project and the Enlightenment volume) encouraged me to find time to write or to talk about ideas amidst the deluge of teaching and home-schooling. There is a particular joy in writing with others to create something different than what you would do on your own. Editing, too, is deeply satisfying; I enjoy helping writers to sharpen their ideas and to pull out their voices.

Laurence: I started work on this project at the same time as on another edited collection. These were my first two larger-scale editorial projects. I am really glad I had gained experience from the Recipes Project as otherwise I would have been entirely overwhelmed. I knew how to write to authors to commission work and how to edit in – hopefully – supportive manner.

Elaine: Yes, absolutely – I echo all the points raised by Laurence and Lisa above!

Had any of your authors contributed to The Recipes Project?

Elaine: Yes, a number of authors in our volume are Recipes Project contributors. Alisha Rankin, who has written about testing and trying medicines, poison trials and panaceas for the Recipes Project wrote a wonderful chapter on ‘Experiences’, skillfully covering the experience of illness, religious experience, experience and medical practice, experience and empire and experience and commerce in a mere 8000 words. I think that it would be rather hard to find a better introduction to the topic! Secondly, Olivia Weisser, who blogged about searching for syphilis in recipe books, penned a fascinating chapter on ‘Disease’ which masterfully offers a overview of various approaches to study the history of disease; detailed case studies of how early modern men and women such as Samuel Pepys (1613–1703) viewed their sickness experiences and an introduction on analysing patient’s narratives to learn more about attitudes to sickness and disease in the past. Offering both a broad historiographical overview and rich case studies, Olivia’s chapter works particularly well for seminar discussions.

Lisa: Marieke Hendriksen wrote a wonderful chapter on objects, focusing on bone as a material. She did talk a bit about recipes, such as how to clean bones and bones in remedies, though this wasn’t her focus. Erin Spinney wrote a great chapter on environment, looking at the built environment of naval and military hospitals in the Caribbean, including the defined roles of particular bodies (according to race and gender) within them. Erin was not a Recipes Project contributor, but she did work as an administrative assistant for us for a summer!

Laurence: David Leith, who wrote the ‘Brain’ chapter had contributed a post on ‘Painting Plants in Roman Egypt‘ for the Recipes Project.

Are recipes discussed in your volume?

Laurence: Recipes are mentioned here and there in various chapters: John Wilkins’ chapter on ‘Food’; Chiara Thumiger’s chapter on ‘Animals’; Rebecca Flemming’s chapter on ‘Experiences’; and my own chapter on ‘Authority’. In addition, Ido Israelowich’s chapter on the ‘Environment’; Patty Baker’s chapter on ‘Objects; and Julie Laskaris’ chapter on ‘Disease’ discuss various ingredients and treatments. Even though recipes were already well covered, I decided that they needed to be given more prominence. So I chose to centre my introduction, which was meant to be a piece of scholarship in and of itself, on a recipe which I keep returning to in my work: Mithradates’ antidote, allegedly created by the King of Pontus in the first century BCE. I found this a very useful device to introduce all the themes in the volume. In a way, that has always been what attracts me to recipes: their structuring power.

Lisa: Beyond Marieke’s chapter, no…. But E.C. Spary’s exciting chapter on food starts with the question ‘what is a food’, as she considers how its definitions are constantly contested and shaped by structures of power. This is very much the sort of thing we’re interested in at the Recipes Project! Despite the lack of recipes, I was pleased with the focus on the dark side of the Enlightenment that emerged in my volume: the tensions between imagination – or the supernatural – and reason (Roger Cooter and Claudia Stein on mind and Angela Haas on authority), the interest in human curiosities as animal-like (Monica Mattfield), and the multiple ways in which race, class and gender were inscribed on the body. It also highlights the continued, but changing, relationship between mind and body, despite the modern tendency to assume a Cartesian split in this period (Micheline Louis-Courvoisier on experiences and Lina Minou on disease).

Elaine: Yes, of course recipes are featured and in so very many of the chapters!  In Olivia Weisser’s chapter on ‘Disease’, for example, recipe titles are used to explore how early modern men and women tended to define diseases as clusters of symptoms. Karin Eckholm’s illuminating chapter on ‘Animals’ explores the use of animal products in early modern medicines, outlining both the use of kitchen staples such as eggs, animal fats and honey and more costly animal ingredients such as spermaceti, ambergris and bezoar stones. Sandra Cavallo discusses recipe collections alongside notebooks and other medical texts in her chapter on ‘Objects’ and, somewhat predictably, recipes and recipe books are dotted throughout Alisha Rankin’s thoughtful chapter on ‘Experience’. Furthermore, centred on Felix Platter, Sachiko Kusuksawa’s chapter on ‘Authority’, discusses Platter’s endeavors in medicinal recipe collection and exchange whilst a student at Montpellier, and places of this kind of informal learning and networking with fellow students and professors within Platters general pursuit of medical knowledge and construction of medical authority. Finally, while recipes are not explicitly featured in Rebecca Earle’s chapter on food, diet and health or Natalie Kauokji’s chapter on environment, diet and natural conditions, these chapters would certainly be of interest to The Recipes Project readers!


Eggs and Invisible Ink: George and Giovanni

By Sean Coughlin

In a 2015 episode of Turn, a US Revolutionary War TV drama on AMC, George Washington’s spy Abraham Woodhull uses a special ink made with alum to write secret messages under the shells of hard-boiled eggs. The technique was also advertised on the show’s Twitter in 2014, a year before the episode aired (Figure 1).

Figure 1: Teaser tweet before the airing of the episode. Image via AMC Twitter.

Turn is based on a 2006 book by Alexander Rose called Washington’s Spies: The Story of America’s First Spy Ring, but there is no mention in the book of any such technique. Instead, it seems to come from a 2009 book by John A. Nagy, Invisible Ink: Spycraft of the American Revolution. That book describes an ink that is able to permeate the shell of a hard-boiled egg, leaving the message hidden inside and no trace of writing on the shell. It is not attributed to George Washington and his spies, however, but to Giambattista della Porta. Nagy writes:

“In the fifteenth century Italian scientist Giovanni Porta described how to conceal a message in a hard-boiled egg. An ink is made with an ounce of alum and a pint of vinegar. This special penetrating ink is then used to write on the hard-boiled egg shell. The solution penetrates the shell leaving no visible trace and is deposited on the surfaced of the hardened egg. When the shell is removed, the message can be read.” (John A. Nagy, Invisible Ink: Spycraft of the American Revolution, 2009: 7)

Nagy’s account of della Porta’s recipe seems in turn to have come from 1999 book by Simon Singh called The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography. Singh, however, leaves it unclear whether the egg is to be hard-boiled or raw when one writes on it:

“In the fifteenth century, the Italian scientist Giovanni Porta described how to conceal a message within a hard-boiled egg by making an ink from a mixture of one ounce of alum and a pint of vinegar, and then using it to write on the shell. The solution penetrates the porous shell, and leaves a message on the surface of the hardened egg albumen, which can be read only when the shell is removed.” (Simon Singh, The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography, 1999: 10)

Singh’s description of della Porta’s recipe only appears in the first edition of The Code Book. In later editions it is missing without comment. The reason might be found by reading della Porta himself, who in Book 16 chapter 4 of his Natural Magic mentions the technique, but neither claims to have invented it nor to have gotten it to work:

“Africanus teaches thus: ‘grind [oak] galls and alum with vinegar, until they have the viscosity of ink. With it, inscribe whatever you want on the egg and once the writing has been dried by the sun, place the egg in sharp brine, and having dried it, cook it, peel, and you will find the inscription.’ I put it in vinegar and nothing happened, unless by ‘brine’, he meant sharp lye, what’s normally called capitellum” (della Porta, Magia Naturalis 16.4: Latin 1590, English 1658)

Della Porta attributes the recipe to Africanus, probably Sextus Julius Africanus, a 2nd–3rd century CE traveler, writer and chronicler, whose recipe for an egg-permeating ink is preserved in the 10th century Greek compilation known as the Geoponica, of which della Porta’s recipe is a literal Latin translation. Unlike Singh’s or Nagy’s recipe, della Porta’s includes oak gall (an ingredient often found in inks as a pigment) and lacks precise measurements.

The measurements and techniques described by Singh seem similar to a recipe printed on page 143 of the 1973 New Earth Catalogue (Figures 2 and 3):

Figure 2: The New Earth Catalogue: Living Here and Now, ed. Scott French and Gnu Publishing, New York: Putnam Berkley Press, 1973. Image via MareMagnum.

Writing Under Shell of an Egg. Dissolve one ounce of alum in a half pint of vinegar and use a small brush to paint whatever you wish to appear on the shell of an egg. After he egg has dried completely, boil it for 15 minutes [...].
Figure 3: P. 143 (detail, via Google Books Snippet View) of The New Earth Catalog: Living Here and Now.
This recipe uses half the amount of vinegar. It also mentions that a small brush is to be used and says to boil the egg for 15 minutes. None of these details are in Singh’s or in della Porta’s version.

This recipe shares a strong family resemblance to a one published by the USDA in 1965, whose purpose was to get children to eat more eggs. We know this because the USDA’s suggestion was picked up by the New York Times and published on page 14 of the 29 May 1965 issue (Figure 4):

Mess on an Egg is Tempting to Child. To increase a child's consumption of eggs, us "invisible writing," the United States Department of Agriculture suggests. Secret messages can be painted on the outer shell of eggs before they are hard-cooked, and nothing will be visible until the egg is cooked and the shell removed. The message will be on the hard-cooked egg white. To make the "magic ink," dissolve one ounce of alum (available in drugstores) in one cup of vinegar. Use a small pointed brush to write on the shell. Let it dry thoroughly and then cook the eggs in simmering water for about 15 minutes. Cool quickly.
Figure 4: P. 14 (detail) of 29 May 1965 New York Times with an invisible ink recipe attributed to the USDA.

Sometime between 10 and 20 years earlier, either in 1946 or 1959, a similar version similarly targeted to children was published in volume 14 of Richards Topical Encyclopedia, an encyclopedia ordered by theme that was sold door to door in the US (Figure 5).

The Warning Beneath the Egg Shell. Mix an ounce of alum with a half pint of vinegar. Then with a fine brush, using the mixture as an ink, write a message--a joke, a prophecy, anything you like--on the shell of an egg. After the egg is boiled in water for about fifteen minutes, the writing will disappear, but your unsuspecting friend who removes the shell will find the message on the hard-boiled egg inside.
Figure 5: P. 136 (detail) of volume 14 of Richards Topical Encyclopedia, published either in 1946 or 1959.

Another 10 (or 20) years before that, we find the recipe on page 58 and 132 of the February 1936 issue of American Druggist. A reader from Oregon asks for the recipe of a solution used to mark eggs. The editor replies that the “trick” is described ‘in Henley’s “Book of Recipes”.’ (Figure 6)

Egg Shell Marking. "Oregon" used to mark eggs with a mixture of brown sugar syrup and some acid. He has forgotten the formula. The trick, as described in Henley's "Book of Recipes" is as follows: (Continued on page 132) Notes and Queries...continued from page 58. Dissolve an ounce of alum in 8 ounces of vinegar and use the solution to "write" upon the egg, using a small pointed camel's hair brush. Dry the egg and boil it for about 15 minutes. By that time the markings on the shell will have disappeared but when the shell is removed the writing will appear on the hardboiled white of the egg.
Figure 6: P. 58 and 132 (detail) of February 1936 issue of American Druggist.

The editor’s recipe is not obviously the one “Oregon” was after (it includes neither sugar nor acid) but the details are familiar: 1 oz alum, 8 oz (= 1 cup = 1/2 pint) vinegar, a small, pointed brush, 15 minutes boiling. Some details are new: we’re told the brush should be camel’s hair (I will come back to this in the sequel).

The editor of American Druggist also gives a source: Henley’s “Book of Recipes”. The Norman W. Henley Publishing company was active in the United States in the early 20th century and beginning in 1907 published almost yearly editions of an extremely popular book of household recipes: Henley’s Twentieth Century Book of Recipes, Formulas and Processes: Containing Nearly Ten Thousand Selected Scientific, Chemical, Technical and Household Recipes, Formulas and Processes for Use in the Laboratory, the Office, the Workshop and in the Home By Gardner D. Hiscox.

I checked the 1907 edition of Henley’s, but found nothing. I continued looking for references to the recipe closer in time to the American Druggist issue to refine the search. I found two earlier instances: page 97 of the January 1930 issue of Popular Science, and (slightly earlier) page 110 of the September 1929 issue of Field and Stream, where it is referred to as ‘an old hex trick’ (Figures 7 and 8):

Making Writing Appear on Whites of Boiled Eggs. An easy and effective trick is to letter a prophecy on the shell of an egg, using a mixture of an ounce of alum in a half pint of vinegar as the medium and applying it with a fine brush. Place the egg in water and boil for about fifteen minutes. The lettering on the shell will disappear, but on removing the shell, the prophecy will be seen on the hard-boiled white of the egg.
Figure 7: P. 97 (detail) of January 1930 issue of Popular Science.

1001 Outdoor Questions. By Iroquois Dahl. Ques. Not long ago I saw the egg of a domestic hen boiled, and when cracked and opened, the following words and figures appeared, perfectly printed on the white of the egg: “Ware will come in 1932.” As I am a disbeliever in hokum and bunk, I would appreciate information on how this was done? Ans. This sounds like an old hex trick. You can write on the inside of an egg by dissolving 1 ounce of alum in ½ pint of vinegar. With a small pointed brush, outline whatever you writing you desire on the shell of the egg with this solution. After the writing has dried thoroughly, boil the egg for 15 minutes. All trace of writing should disappear from the shell, and when the egg is cracked and shelled, the writing will appear on the hard-boiled white.
Figure 8: 1985 reprint of p. 110 of September 1929 issue of Field and Stream.

If Henley’s was the ultimate source, the recipe had to have appeared sometime before 1929. I checked the 1925 edition, but it was nowhere to be found. The next edition was published in 1929, the same years as the Field and Stream recipe. There it was on page 786 (Figures 9 and 10):

Wood Polishes; Wood Renovators; Wood, Securing Metals To; Wood, Waterproofing; Wood’s Metal; Wool Fat; Worm Powder for Stock; Writing, Restoring Faded […].
Figure 9: P. 786 (detail) of Henley’s, the 1925 edition. No recipe.

Wood Polishes; Writing Under the Shell of An Egg: Dissolve one ounce of alum in a half pint of vinegar with a small pointed brush outline whatever writing you desire on the shell of the egg with the above solution. After the solution has dried thoroughly on the egg, boil it for about 15 minutes. If these directions are carried out all tracings of the writing will have disappeared from the outside of the shell--but when the shell is cracked open the writing will plainly show on the white of the egg.
Figure 10: P. 786 (detail) of Henley’s, the 1929 edition, with the earliest version the author could find of this recipe.

The recipe contains many of the characteristics of the one that has been passed down in American lore and attributed in one form or another to George Washington’s spies or Giambattista della Porta: 1 oz. alum, ½ pint vinegar, a small brush, 15 minutes of boiling.

Given the reach of Henley’s “Book of Recipes” in the US, this is not surprising. But Henley’s recipe also lacks a key ingredient from the recipe that della Porta attributed to Africanus: oak gall. How and when this ingredient dropped out from a recipe reliably passed down for over a thousand years is another story.

This post continues a study of how a 3rd century recipe for a magic ink, despite the fact that it probably never worked, still managed to work its way into American popular culture in the 20th and 21st centuries. An earlier part of the study is posted here.