Tag Archives: students

The “Gentle Heat” of Boerhaave’s Little Furnace

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 postdoctoral researcher on the Artechne 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.

With the introduction of chemistry into the university curriculum in the late seventeenth century, new practical needs arose for students  such as being able to perform experiments. Would it be possible to build a chemical furnace that provides a gentle heat, yields no smoke, and is safe for students to use? Herman Boerhaave (1668–1738) believed he found the perfect solution in, what came to be called, Boerhaave’s little furnace.

Portrait of Herman Boerhaave by Cornelis Troost, c. 1730.

Boerhaave was professor of medicine, botany and chemistry at Leiden University in the early 18th century.[1] Instead of starting with the most difficult experiments with metals and minerals, he was convinced that students were better off when they learned the techniques of through simpler processes, such as distilling leaves and flowers, and fermenting bodily fluids. But most chemical laboratories were equipped with elaborate devices too complicated for freshmen students, who in the eighteenth century could be as young as fourteen. Moreover, the brick-build furnaces were designed to create high temperatures, in which small and delicate materials like rosemary leaves would burn instantly.[2] Boerhaave hence needed a device that was low-cost, user-friendly, and would provide a gentle heat.

The plan for the oven, • H. Boerhaave, Elementa Chemiae, Quae Anniversario Labore Docuit in Publicis, Privatisque Scholis, (Leiden 1732).

A small wooden oven was the answer. Boerhaave claimed he had designed this type of furnace when he himself was studying chemistry in the 1690s. He opened the chapter on instruments in his chemistry textbook with the words: “I shall begin with my simplest furnace; which I invented forty years ago, when I practiced chemistry in no large study, where there was only one little chimney, and where I required several furnaces at once.”[3]

Woman at the Virginal and stove under her feet, by Jan Miense Molenaer, 1630-1640. Rijksmuseum, Amsterdam.

This kind of device was probably inspired by ordinary foot stoves. These little stoves, also known as foot warmers, were very popular in the Dutch Republic. Coming in a wide variety of shapes (square, octagonal, cylinder), these stoves often feature in books and paintings. Filled with glowing coals or peat, women placed the little stoves under their robes or blankets to keep warm.[4] Many foot stoves were equipped with a wire bail handle for lifting and easy transportation. Such stoves were used in carriages, sleighs, at home and in church to keep one’s feet warm. This ordinary foot warmer got new applications too, namely as tea and coffee stove,   and we suspect it was the model for the ‘simplest furnace’ in the Leiden chemical laboratory.

Woman carrying a little stove, Harmen ter Borch, 1648–1677. Rijksmuseum, Amsterdam.

The gentle heat produced by Boerhaave’s small oven proved very useful in performing all kinds of chemical experiments. Take rosemary, for example, the evergreen aromatic shrub. Distilled atop a “violent fire”, it would have been turned to flame, smoke, and ashes. But when rosemary instead was distilled at “summer-heat” (approx. 85º F), the mild operation would instead reveal the most volatile, fragrant and aromatic part of the plant ordinarily exhaled in summer. The same process could be applied to Angelica, basil, and all other aromatic plants.

Students in the Leiden laboratory, in Herman Boerhaave, Institutiones et experimenta chemiae (‘Paris’, 1724). Ghent University Library.

Boerhaave, in other words, attributed the success of his device to one’s control over gentle heat. Whenever the wooden oven was filled with hot pieces of coal or Dutch turf that was no longer smoking, it established a constant and moderate heat that could be kept up to 24 hours. As such, the instrument was perfect for students to perform all kinds of heating processes and distillations. In fact, he was so excited about this apparatus, that he claimed that “I believe eggs may be hatched by it”.[5]

Was Boerhaave’s little furnace really that user-friendly and effective as he claimed it was? We checked it out by recreating Boerhaave’s stove and performing experiments with it. Check out our next blog to entry to find out whether we succeeded!

Creating an oven from two old stoves… to be continued!

References:

[1] More on Boerhaave, see Marieke Hendriksen, “Boerhaave’s Mineral Chemistry and Its Influence on Eighteenth-Century Pharmacy in the Netherlands and England”, Ambix(2018) and Ruben Verwaal, “The Nature of Blood: Debating Haematology and Blood Chemistry in the Eighteenth-Century Dutch Republic”, Early Science and Medicine(2017).

[2] Boerhaave, Elementa Chemiae (Leiden:  Isaac Severinus, 1732), vol 2, experiment 1.

[3] Ibid., vol 1.

[4] Le Francq van Berkhey,Natuurlyke historie van Holland (Amsterdam: Yntema and Tieboel, 1769–1778), vol. 3, 706-707, 1200.

[5] Boerhaave, Elementa Chemiae, vol 1.

Gluttony and “Surfeit” in Early Modern Europe

By Carla Cevasco

From buttery stuffing to champagne, the holidays give us plenty of opportunities to indulge…and plenty of nutritional advice on how to avoid holiday decadence. Early modern Europeans likewise feared gluttony and offered remedies for overeating, but I can’t say that I’ll be too tempted to try any of them myself this holiday season.

In famine-wracked early modern Europe, gluttony was the deadliest of the seven deadly sins, and as The Divine Physician warned in 1676, “Diseases are the Interests of Sin.”[1]  Medical professionals instructed their readers to restrain their appetites in the interest of physical and spiritual health. “Take heed of surcharging thy stomach,” Raymundus Mindererus cautioned in 1674, noting that there was “nothing more hurtful to health” than an “extravagant” appetite. Thomas Tryon’s 1698 The Way to Health recommended a kind of fasting cleanse, claiming that “a little gentle Hunger” cleared “superfluous Matter” from the digestive system (43). An 1816 print (shown below) by Thomas Rowlandson depicted an obese man dining with Death.

Thomas Rowlandson, The Dance of Death: The Glutton, aquatint, 1816. Image Credit: Wellcome Library, London.
Thomas Rowlandson, The Dance of Death: The Glutton, aquatint, 1816.
Image Credit: Wellcome Library, London.

Warnings against gluttony did not always sit well with readers. Louis-François Charon’s print “Le Médicin et la Malade” (shown below),  in which a gluttonous doctor instructed his patient to go on a diet, mocked medical professionals’ emphasis on moderation and suggested that they failed to practice what they preached.

V0011678 A doctor instructs his English patient not to eat as he does Credit: Wellcome Library, London. Wellcome Images images@wellcome.ac.uk http://wellcomeimages.org A doctor instructs his English patient not to eat as he does. Coloured engraving by Louis-François Charon. after: Louis-François CharonPublished: - Copyrighted work available under Creative Commons Attribution only licence CC BY 4.0 http://creativecommons.org/licenses/by/4.0/
Louis-François Charon, “Le Medicin et le Malade,” colored engraving (undated).   Image Credit: Wellcome Library, London.

Medical practitioners even recognized specific, pathological forms of overeating. Phillip Barrough‘s 1601 The Practice of Physick described the “Doglike appetite,” which caused sufferers to “devoure in meate without measure” before “vomiting like dogges” (110-11). For a curative diet, Barrough prescribed stale bread, herbs, “fat & oily” meat, mallows, and most of all, wine, to “heate the stomacke, and destroy the sharpnesse of humours” that provoked patients to a canine hunger.

For those unable to heed injunctions against overeating, many recipe books offered remedies for “surfeit.” A recipe “To Make Poppies Water which is Good for a Surfeit,” in Wellcome MS 4054, called for soaking “Corn poppys,” marigolds, gillyflowers, sweet marjoram, angelico root, raisins, licorice, aniseeds, white sugar, and rosasolis in aquavitae, then straining and bottling the resulting cordial. John Gerard’s Herball or Generall Historie of Plants noted that “black Poppy drunketh in wine” stopped diarrhea; in addition, the opioid content of distilled poppy flowers or leaves would have eased the pain associated with indigestion (400-401). I would be interested in hearing from other scholars here about how the other ingredients of poppy waters might have affected their consumers.

Sala (Angelus), Method of Extracting the Juice from the Poppy, Woodcut, from  Opiologia, or a Treatise...of Opium (1618).  Image Credit: Wellcome Library, London. Credit: Wellcome Library, London. Wellcome Images images@wellcome.ac.uk http://wellcomeimages.org Method of extracting the juice from the poppy. Woodcut Opiologia, or a Treatise....of Opium Sala (Angelus) Published: 1618 Copyrighted work available under Creative Commons Attribution only licence CC BY 4.0 http://creativecommons.org/licenses/by/4.0/
Sala (Angelus), Method of Extracting the Juice from the Poppy, Woodcut, from 
Opiologia, or a Treatise…of Opium (1618). 
Image Credit: Wellcome Library, London.

In a world where people constantly risked lapsing into gluttony, and suffering ill health as a result, lack of appetite was also cause for particular concern. Medical writers identified several types and causes of loss of appetite. Barrough claimed that physiological defects, humoral imbalances, and/or sickness could result in a loss of appetite. In A New Practice of Physick, volume 1, Peter Shaw wrote that a patient might experience “anorexia,” or a long-term distaste for food, “from hard drinking, great heat, a fever,” or “consumptions” (170-71). Medical writers agreed that lack of appetite did not spontaneously occur in a healthy person, but rather could be linked to a hangover, hot weather, sickness, or bodily dysfunction.

To “provoke appetite againe,” Barrough suggested exposing the patient to pleasant odors, such as “wine infused, or decoction of quinces, or peares,” and anointing the patient with fragrant oils “of roses, masticke, and such like.” After aromatherapy, Barrough prescribed a diet of “diverse” foods “after the daintiest fashion,” including corn, eggs, “birds of the mountaines,” dates, and prunes. While medical writers blamed “variety of meats” and “curiously and daintily dressed” foods for gluttonous excesses, Barrough harnessed the appetite-stimulating powers of delicious smells and tantalizing nibbles to encourage those who had lost their hunger to find it again.[2]

Today we might reach for pink bismuth subsalicylate instead of a poppy cordial after a big meal, but early modern Europeans had many of the same questions that we do about how much to eat.

Pepto Bismol. Image Credit: Flickr user Herr Hans Gruber. Via Flickr.
Pepto Bismol. Image Credit: Flickr user Herr Hans Gruber. Via Flickr.

[1] Robert Appelbaum, Aguecheek’s Beef, Belch’s Hiccup, and Other Gastronomic Interjections: Literature, Culture, and Food among the Early Moderns (Chicago: University of Chicago Press, 2006), 114, 243-245.

[2] Nicholas Culpeper, Medicaments for the Poor; Or, Physick for the Common People (Edinburgh, n.p., 1664), 10.