Wrote Letter 60 of 1687-11-28 (AB 105) to Members of the Royal Society about his discovery that cochineal was an insect and his experiments with cinchona bark

November 28, 1687
Standard reference information
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Text of the letter in the original Dutch and in English translation from Alle de Brieven / The Collected Letters at the DBNL - De Digitale Bibliotheek voor de Nederlandse Letteren.

The original manuscript, written and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 1926, EL.L2.17).


Plate from
Continuatio Epistolarum

Figures 1 - 5

The original drawings are lost. The Dutch and Latin editions that Leeuwenhoek published used the same plate with all five figures. The one below (click to enlarge) came from the 1730 fourth edition of Continuatio Epistolarum, as did the images on the sidebar. In the text, Leeuwenhoek noted that someone else drew the figures.

Other publications

While the Royal Society did not publish this letter in Philosophical Transactions, it was extracted twice in foreign journals, as were all the letters in Vervolg der Brieven, Letters 53 through 60. In the year after it was written, Jean Le Clerk published a short excerpt, including none of the figures, in Bibliothèque universelle et historique, vol. 9, p. 163-164.

In 1689, Otto Mencke pubished a short excerpt, including none of the figures, in Acta eruditorum, vol. 8, p. 174.