Wrote Letter L-078 of 1679-02-21 to Nehemiah Grew about cod sperm and about not finding any little animals in blood or saliva

February 21, 1679
Standard reference information
Leeuwenhoek's number: 
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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

A photocopy of the original manuscript (to be found in The National Archives, Kew), on four folio pages, written and signed by Leeuwenhoek, is preserved at the Royal Society (Early Letters L1.39a).

This letter probably never reached the Royal Society. It was not published in Philosophical Transactions.

Leeuwenhoek wrote this letter to Nehemiah Grew (never received) about:

  • his examination of blood and saliva to discover whether they contain living organisms
  • his refutation of the opinion that living organisms occur in blood and saliva
  • an account of liver-flukes and the origins of the disease in sheep
  • the sperm of cod

This letter never reached the Royal Society. It was found by Petra Beydals of Delft.

This is one of the two (?) letters in which he mentions his wife Cornelia and daughter Maria.

Govert Bidloo referred to this letter in his Letter L-338 of 21 March 1698 about, among other things, the worms that he found in sheep livers. Because it was never published during Leeuwenhoek's lifetime, Bidloo must have seen a copy that Leeuwenhoek kept.