A Cool Oven: Boerhaave’s Little Furnace, part II

By Ruben Verwaal and Marieke Hendriksen

Ruben Verwaal is curator of the historical collections at Erasmus Medical Centre, Rotterdam, and at the Museum for Communication in The Hague. He obtained his PhD in June 2018 with a thesis on the role of bodily fluids in eighteenth-century chemistry. Marieke Hendriksen is a researcher on the Artechne Project and PI at the Art DATIS Project at Utrecht University and a long-time contributor to The Recipes Project. She specializes in the material culture of science and art in the long eighteenth century. Ruben and Marieke share an obsession with an eighteenth-century object that has since disappeared: a small chemical furnace. In a previous post, they wrote about reconstructing Boerhaave’s little furnace. Now they have two…

The newly build oven, August 2018

In August of this year, we wrote about our first attempt to recreate Boerhaave’s little furnace from old coal stoves. Meanwhile, Marieke’s dad, André, who is a skilled carpenter, was building a furnace from scratch, using Boerhaave’s description and a nineteenth-century example of a Boerhaave furnace in the collection of Museum Gouda as his guidelines. This resulted in a sturdy furnace of solid dried oak, much larger than the furnace we created from coal stoves.

The interesting thing about Boerhaave’s furnace is that many of the experiments that he described in his chemistry book, the Elementa Chemiae, for which the furnace can be used, required a very moderate degree of heat – one could say a cool rather than a hot oven. Two examples we mentioned previously were the distillation of rosemary, and the hatching of eggs, which Boerhaave said he believed his furnace could be used for too. The kind of egg is not specified, but for chicken eggs, the ideal temperature for hatching is 37,6 Celsius. Could we attain that temperature with our furnaces? 

Boerhaave advised to use glowing coals or Dutch turf as fuel, with which a constant and moderate heat should be achieved that could be kept up to 24 hours. As turf is no longer won in the Netherlands, we started with some ordinary barbeque coals – and indeed managed to establish a fairly constant heat of around 30 Celsius in the large oven for an hour or so. But coals did not hatch any chicks.

Coals: a stable 30 Celsius

Suspecting that turf may give better results, we set out to buy turf, which is still won in regions in Germany and Ireland. It turned out to be surprisingly difficult to buy in the Netherlands though. Eventually we managed to purchase a box of Irish turf through the American website of the online retailer we love to hate – but it took eight weeks (!) to arrive.  Though our cool oven still hasn’t incubated a chicken, the first results look promising.

Irish peat via the US
Irish peat via the US

Meanwhile, we started thinking about the experiments we’d like to recreate once we had all necessary materials. Since Ruben wrote his PhD thesis about bodily fluids, he is keen on reconstructing an experiment with milk from different mammals. Preferably, we’d compare the effects of prolonged mild heat on cow’s milk and human breast milk. Raw cow’s milk can be purchased at some farms, so Ruben cycled out to get some, while Marieke hesitantly contacted a friend who was pumping to feed her infant daughter to ask if she was willing to donate some of her leftovers to science. Note for future generations: Marieke has the coolest friends – she instantly said yes! For weeks, she gathered the left overs that her daughter did not drink in freezer bags.

Suddenly, it is December, and we have two furnaces, a box of Irish peat, and milk in two freezers. Now we ‘only’ have to make time for this reconstruction experiment… We live an hour apart and this is our pet project, so we’re desperately searching for a couple of days when we can take time of work. It turns out that the most difficult aspect of this reconstruction project is not the building of the furnaces or the sourcing of the necessary materials, but the absence of what Boerhaave obviously did have: cheap labour in the form of young assistants, who could take turns keeping the furnaces going day and night. We can only hope that once we do manage to take those days off, the Dutch winter is still as mild as it has been up till now! 

“Bonny-Clabber Physicians”: Eating Clean in the Seventeenth Century

Michael Walkden

NPG D31284; Thomas Tryon by Robert White, after Unknown artist, line engraving, 1703. Credit: WikiCommons.
NPG D31284; Thomas Tryon by Robert White, after Unknown artist, line engraving, 1703. Credit: WikiCommons.

The concept of ‘clean eating’ is nothing new, but ideas about what constitutes ‘clean’ or ‘dirty’ food have varied within and across cultures. In the later seventeenth century, the popular health writer Thomas Tryon promoted a “radically clean” vegetarian diet as a route to longevity and clarity of mind. However, Tryon’s meat-free menu was rather different from the quinoa bowls and kale smoothies of modern-day clean-eaters. His 1694 Pocket-companion contains the following recipe (easy to follow, but emphatically not to be tried at home):

Boniclabber is made by letting your Milk stand till it sowers, which will be in Twenty-fours hours, if the weather be very hot. [1]

Tryon’s ‘bonny clabber’ – an Irish country dish that was later enjoyed by immigrants to the USA – would have great difficulty in meeting twenty-first century Western standards of food hygiene. Writing well before the advent of pasteurization, Tryon would likely have used raw milk straight from the cow, which would have been rich in bacteria that could be both beneficial and harmful to the human body. If it was left at just the right temperature and for the appropriate length of time, the finished product would be a thick, fermented milk, similar to yoghurt or kefir.

Perhaps unsurprisingly, not all of Tryon’s contemporaries shared his enthusiasm. Gideon Harvey wrote that “Bonny-Clabber Physicians” routinely endangered their patients by their over-use of milk products, which he viewed as highly corruptible and prone to curdling in the belly. [2] Harvey had the weight of medical tradition on his side. Humoural physicians since Hippocrates frequently expressed mistrust or even fear over the coagulability of milk, with Galen writing that it “turns to wind in the stomachs of most people, and there are very few who avoid this.” [3]

Clabbered milk. Credit: WikiCommons.
Clabbered milk. Credit: WikiCommons.

Tryon attempted to forestall this sort of criticism in his own writing. Since he believed that digestion operated by a process of fermentation, it logically followed that fermented foods should be easier on the stomach, having already undergone the initial stages of this process. While he was prepared to admit that it “may not be so agreeable to the Pallat at first”, Tryon assured his readers that “a little Custom will make it familiar and pleasant.” [4]

Attitudes towards the healthiness of clabber were also closely tied up with racial stereotypes about the Irish, whose perceived gluttony and barbarism were ridiculed by many English Protestants. In 1652 the parliamentarian Samuel Sheppard wrote of an anonymous royalist that “his Intellect is as foule, as an Irish Firkin of Bonny Clabber”, suggesting that many viewed it as a disgusting or dangerous substance. [5] By contrast, in a 1635 letter from Dublin, the English royalist and Lord Deputy of Ireland Thomas Wentworth described clabber as “the bravest freshest Drink you ever tasted.” [6]

The example of bonny clabber raises some interesting questions about the relationship between ideology and diet. As Carla Cevasco has flagged up elsewhere on this blog, the categories that shape affective responses to food can be highly variable, ranging from the genetic makeup of a population to its social norms. Disgust that feels instinctive or biologically hard-wired might just as easily be the product of a specific cultural moment. As the debate over clean eating continues to rage, we need to pay closer attention to the ideological fault-lines upon which we construct our ideas about food and hygiene.

[1] Thomas Tryon, A pocket-companion, containing things necessary to be known by all that values their health and happiness (London: Printed for George Conyers, 1693), 6.

[2] Gideon Harvey, The art of curing diseases by expectation (London: Printed for James Partridge, 1689), 38.

[3] Galen, Galen on Food and Diet, ed. Mark Grant (London and New York: Routledge, 2000), 165. See also Ken Albala, “Milk: Nutritious and Dangerous,” in Milk: Beyond the Dairy: Proceedings of the Oxford Symposium on Food and Cookery, 1999, (Devon, UK: Prospect Books, 2000), 19-30.

[4] Tryon, Pocket-companion, 7.

[5] Samuel Sheppard, The vveepers: or, the bed of snakes broken (London: Printed for Thomas Bucknell, 1652), 6.

[6] Thomas Wentworth, The Earl of Strafforde’s Letters and Dispatches, Volume 1, ed. William Knowler (London: Printed for the editor, by William Bowyer, 1739), 441.

Michael Walkden is currently completing his doctoral thesis in History at the University of York, UK. His research explores understandings of the relationship between emotions and digestion in early modern English medicine. He is particularly interested in the intersection of diet, health and spirituality in the seventeenth century.

Human Milk as Medicine in Imperial China: Practice or Fantasy?

By He Bian

What does milk have in common with blood? According to Kou Zongshi (fl. 1110-1117), author of Bencao yanyi (Extended Interpretations on Materia Medica), they are basically the same vital fluid produced by the female body at two critical moments in a woman’s life. While the first menstrual period signifies the maturation of reproductive power, motherhood is the consummation of that power–miraculously causing the vital fluid to flow upward as milk. After nursing ends, the flow of milk again reverses back to blood, as evident from the return of the menses.

“Human milk.” Anon. Buyi Leigong paozhi bianlan (n.p, 1591), Book 8.
“Human milk.” Anon. Buyi Leigong paozhi bianlan (n.p, 1591), Book 8.

For centuries, Kou’s comment was repeatedly quoted as the dominant theory over lactation in the realm of learned medicine. It also coincides with parallel attempts to speculate on the metaphysical foundation of sex differences in women, and the consolidation of women’s medicine (fuke) and pediatrics (erke) as medical specialties.[1]

However, Kou’s original aim was to make sense of medical recipes. In particular, he was trying to figure out why do so many recipes for eye medicine use human milk to mix up powdered mineral drugs: a practice that has parallels in different cultural contexts. Since blood is essential for the five senses to function and human milk is essentially blood, Kou reasoned, this makes it an excellent medicine for eye diseases. Another recipe that may have been on his mind is the recommendation to drink “three portions of human milk” to help with obstructed menses. It makes sense if they were considered of the same origin. Like cures like.

Let’s pause here to consider what this means. Working with Chinese materia medica texts often means untangling different strands of thought, modes of compilation and miscellaneous quotations. The entry on each substance (e.g. human milk, renru or ruzhi) often begins with a learned survey of previous literature, including passages from classical literature and histories, and ends with a large (and often unwieldy) body of recipes. The problem is that the prescribed uses of the substances in the first part do not always sit well with the recipes, which are messy, opaque, and often outright strange.

In fact, Kou Zongshi’s work could be understood as a scholar-physician’s attempt to impose order and coherence on the unruly recipes, which were becoming increasingly available in print. [2] The incongruities and tension between theory and recipes, however, allows us to follow the intricate dance between empiricism and rationalism in such texts: when did authors equate recipes with real-life experiences, and when did they treat them as exemplars of theory and formulaic principles? When did book culture begin to shape the ways in which medicines were prepared, consumed, and invented?

Back to Kou Zongshi’s ingenious, if somewhat contrived, speculation over the nature of lactation. It did not seem to have caught much attention immediately. The twelfth and thirteenth centuries witnessed a growing suspicion among medical experts to discipline and curb wet nurses’ sway over childcare, and pediatric treatises abound with warnings against drunken, naughty wet nurses whose milk turns unwholesome to the infant.[3] Again, the female body’s power to nourish but also intoxicate with her transformed milk resonates with similar discourses discussed elsewhere on this blog; notably, alcoholic drinks were seen to be a bad thing that excites her passions, in contrast to ancient Roman recommendations.

In addition, the conquest of Mongols brought about increased consumption of cow and goat’s milk.[4] A leading physician active in the fourteenth century advised consuming those over human milk, which is easily “tainted with poisonous passions.” It looks like the arrival of more abundant dairy products would transform the existing pharmacopeia once and for all.

But not so simple. By the sixteenth century in China, human milk had become a “super food” of sorts, especially among elite families. Kou Zongshi’s dusty theory became a dominant trope, fanning the imagination of the female body as a machine of alchemical wonders, and her milk a sort of elixir that revitalizes the frail and depleted bodies. In the sixteenth-century encyclopedia Systematic Materia Medica (Bencao gangmu), Li Shizhen, the erudite naturalist and capable physician, criticized the excessive fetishizing of human milk. The prudent Li nevertheless included twelve “new recipes” that involve human milk as medicine. Li’s encyclopedia was first printed in 1596; soon after the turn of the century, dietary manuals began to teach people how to prepare dried milk powder at home, after collecting fresh milk from “strong women who just gave birth to boys”. Presumably, women sold their milk not as wet nurses, but directly to pharmacists (as depicted in the picture above).

So did people in imperial China consume human milk as medicine? Quite likely. But was it ubiquitous? Probably not. Recipes can be practical and fantastic, and theorists can explain and inspire. What matters is that human milk as medicine gradually came to be taken out of the context of nursing and acquired a more abstract quality as commodity.

[1] Charlotte Furth, A Flourishing Yin: Gender in China’s Medical History: 960–1665 (Berkeley, CA: University of California Press, 1999).

[2] Asaf Goldschmidt, The Evolution of Chinese Medicine: Song Dynasty, 960-1200 (London ; New York: Routledge, 2009).

[3] Ping-Chen Hsiung, “To Nurse the Young: Breastfeeding and Infant Feeding in Late Imperial China,” Journal of Family History, 20, 3 (1995), pp. 217-38.

[4] Paul D. Buell, E.N. Anderson, and Charles Perry, A Soup for the Qan : Chinese Dietary Medicine of the Mongol Era as Seen in Hu Sihui’s Yinshan Zhengyao, 2nd Rev. and Expanded ed. (Leiden, The Netherlands: Brill, 2010).

Say – horse – cheese

By Laurence Totelin

Last time I blogged for the Recipes Project, I talked about mares. I’d like today to return to mares, their milk and the cheese made with it.

Gold Scythian belt buckle with horse. Seventh century BCE. Source: Wikipedia
Gold Scythian belt buckle. Seventh century BCE. Source: Wikipedia.

These were not delicacies that the Greeks and Romans themselves enjoyed. Instead, they had observed their consumption among the Scythians, a series of tribes, often nomadic, inhabiting large expanses of Eurasian steppes in antiquity. The Scythians, and their taste for mare’s milk and cheese, were a topic of fascination among the classical Greek authors. The historian Herodotus devotes a long passage to the way in which the Scythians milked their mares: they used slaves they had blinded for that purpose. One slave blew into the mare’s vulva with a bone tube, while another milked the mare (Histories 4.2). This is a well-known and much discussed passage among ancient historians. Enough to state here that much appears to have been lost in translation between the Scythians and Herodotus’ source! The Greeks did not drink milk themselves on a regular basis (although they used it in medical context), and established a linked between ‘otherness’ or ‘barbarism’ and milk drinking.

What will retain me today is the use of the mare’s cheese recipe in a physiological analogy. The author of the Hippocratic treatise On Generation, On the Nature of the Child and Diseases IV (which dates to the end of the fifth century BCE or the beginning of the fourth) was very fond of analogies, some of which are rather wacky. In the passage that concerns me, he compares the physiological process whereby a bad humour is heated and agitated in the human body to the making of mare’s cheese:

If the man is not purged, as the humour is stirred, there is produced an amount that is excessive. This is similar to what the Scythians make with mare’s milk. For they pour the milk into wooden bowls and shake it. As it is stirred, it foams up and separates. The fatty part, which they call butter, as it is light rises to the surface; the heavy and thick portion sinks to the bottom; they separate it and dry it. When it has become firm and dry, they call it ‘hippakē’. The whey of the milk is in the middle. Similarly in the case of man: when all the humour in his body is stirred, all the humours are separated by the principles I have mentioned: the bile rises to the top, as it is lightest; then comes the blood; third the phlegm; and the water, as it is the heaviest of the humours. (Diseases 4.51, 7.584 Littré)

Milk curdling: butter at the top, whey, solids at the bottom. Source: MARTYN F. CHILLMAID/SCIENCE PHOTO LIBRARY
Milk curdling: butter at the top, whey, solids at the bottom. Image Credit: MARTYN F. CHILLMAID/SCIENCE PHOTO LIBRARY

This is a rich and surprising passage. It mentions four humours, but those are not the four humours we all know (bile, phlegm, blood and black bile). Instead, we find bile, blood, phlegm and water. It is relatively little known that there is only one text in the Hippocratic Corpus that mentions the four humours that would become, under the influence of Galen, canonical: Nature of Man. The number and name of humours varies from one Hippocratic treatise to the next. Our author has a predilection for his ‘water’, the heaviest of all his humours, which he compares to the heavy portion to the Scythian milk. One wonders why this Greek author has chosen a Scythian process as a comparing point. The Greeks did make cheese, but their cheese was of the soft type, kept in brine. They did not make butter and hard cheeses. They did not churn (shake) their milk. The recipe the author provide is reasonably clear, although I would personally find it difficult to make cheese by following it. Looking forward to my feta-based dinner now!