Here I am, one month into a visiting fellowship at the Max Planck Institute for the History of Science in Berlin – a wonderful institution full of scholars from all around the world working on a wide variety of topics. As you can imagine, a lot of tea and coffee is consumed here to keep everyone going. With all those different backgrounds, that leads to heated discussions about where the best coffee in the neighbourhood is sold, and what the right way is to make tea. That, combined with a remark about tea not spoiling in green glass in a text I was researching, reminded me of Cornelis Bontekoe (1647 – 1685), alias the tea doctor, who was born in Alkmaar (the Netherlands) and died here in Berlin.

Cornelis Bontekoe.
Copperplate by Adriaen Haelweg.

Bontekoe was born Cornelis Dekker, but took the surname Bontekoe (literally ‘spotted cow’ in Dutch) after the spotted cow on the shield of his father’s grocery shop. After obtaining his M.D. at Leiden University in 1667, he established a practice as a physician in Alkmaar. Bontekoe strongly advocated the use of fashionable products such as tea, coffee, cacao and tobacco to improve one’s health, which led to suspicions that he had a deal with the Dutch East Indian Company, the big importer of these products at the time. Deal or not, Bontekoe, who was known in intellectual circles as a passionate Cartesian and who went on to have a career as a university professor and court physician in Hamburg, Frankfurt, and Berlin, would go down in history as ‘the tea doctor.’

This was mainly due to his Tractaat van het excellenste kruyd Thee, or tractate on the most excellent herbal tea, subtitle ‘which shows the right use, and the great powers of it in health, and sickness, printed in The Hague in 1678 and reprinted repeatedly. The first part of the tractate is rather curious, an anti-Aristotelian rant that criticizes the wide-spread beliefs that drinking water is bad for you, beer, wine, and butter milk preferable, and the apparent dominant ideal of beauty:

People hate and despise the small and delicate, the skinny and emaciated Bodies, which resemble a ghost or a skeleton rather than a man. People want to be fat, big, and coarse, stout and well-build, full of power and vigor; one should be able to hold down one’s liquor, that is health!

Title page to Cornelis Bontekoe’s Tractate on Tea

In over 300 pages, Bontekoe refutes common misunderstandings about tea, such as that it would dry out the body, weaken the stomach, stimulate the production of bile, cause shaky limbs, epilepsy, and even infertility. He argues that although drinking cold water is unhealthy, boiled water with the added benefit of the ‘herb of tea’ has a beneficent effect on the mouth, digestive system, blood, and mind, hydrating the body without intoxicating it, stimulating digestion and reducing flatulence.

Tea according to Bontekoe stimulates the mind, improves ones mood, prevents kidney and bladder stones, can help cure gout and he common cold, and warms the blood, but mixed with milk and sugar tempers excessive heat in the body. My favourite argument however is that of the huge size and population of countries like China and Japan, where people drink tea all their lives.

Ladies drinking tea, Pieter van den Berge, ca. 1694 – 1737. The verse at the bottom of the page satirizes the fashion of drinking tea. Courtesy of the Rijksmuseum. http://hdl.handle.net/10934/RM0001.collect.78565

The tractate closes with a chapter on what good tea is: as fresh and white as possible, not too bitter, made with fresh, clean rain water that has not been boiled too long, and it should be drunk from earthenware or tin cups instead of copper ones. Tea should be not too strong, and no sugar should be added. Although there is no limit to the amount that can be had, yet those who want to sleep well at night should not drink it after midday.

As for Boerhaave’s remark that tea spoils in clear glass but remains uncorrupted in green glass; this appears to have had something to do with the fact that “by using a great deal of salt to a small quantity of flints, the glass becomes very clear; but is weak and frail, apt to crack by fire and water, and by age grows dull; and even infects liquors put in it, and sometimes destroys them utterly.” Green glass was generally stronger than clear glass, although the green colour came from copper oxides – the one substance Bontekoe warned not to drink one’s tea from….

Cup of tea, anyone?

Sources:

Bontekoe, Cornelis, Tractaat van het excellenste kruyd thee: ‘t Welk vertoond het regte gebruyk, en de grote kragten van ‘t selve in gesondheid, en siekten: benevens een kort discours op het leven, de siekte, en de dood: mitsgaders op de medicijne, en de medicijns van dese tijd, en speciaal van ons land. Ten dienste van die gene, die lust hebben, om langer, gesonder, en wijser te leven, als de meeste menschen nu in ‘t gemeen doen. (The Hague: Pieter Hagen, 1678).