Wrote Letter L-565 of 1720-01-09 to the members of the Royal Society about muscle fibres and membranes of a cow, mites on the flesh of a whale, and the nerves around the muscle fibres and tendons of a cow

January 9, 1720
Standard reference information
Collected Letters volume: 

Text of the letter in the original Dutch and in English translation in Alle de Brieven / The Collected Letters is not yet available at the DBNL - De Digitale Bibliotheek voor de Nederlandse Letteren.

With this letter, the correspondence between Leeuwenhoek and the Royal Society was re-established now that James Jurin had replaced Edmond Halley as editor of Philosophical Transactions. In his previous letter to the Royal Society, Letter L-562 two years earlier,  declared that letter his final letter to the Royal Society, perhaps not expecting to live long enough to see Halley's replacement.

Signed autograph letter. The manuscript is to be found in London, Royal Society, MS 2109, Early Letters L4.60; 6 quarto pages; 1 engraving. There is also preserved a copy of the letter in Letter Book Original 15.79, p. 291, 6 pages, and a contemporary English translation of the letter by Dr Sprengell, MS 2110, Early Letters L4.61; 6 pages.

Conrad Joachim Sprengell, M.D. (d. 1740) was born in Leipzig and received his medical degree in Angiers in 1710. He was admitted to the Royal College of Physicians in 1719 and was made a fellow of the Royal Society in 1721. He was knighted in 1725 and published a translation of the Aphorisms of Hippocrates and Sentences of Celsus in 1735.

Sprengell's translation was not read until two years later, during a meeting of the Royal Society on 7 March 1722 O.S., after James Jurin was elected second secretary and editor of Philosophical Transactions on 30 November 1721.

Leeuwenhoek ended the letter with a personal postscript.

I made these discoveries towards the end of last year and put them down on paper in the beginning of January of this year. If there is something wanting there, you might kindly remember my very advanced years, which, if I come to celebrate my birthday this year, will be 88, and with health, I shall shortly send Your Honours some more of my discoveries.