Wrote Letter L-126 of 1683-05-20 to Anthonie Heinsius about generation and about the circulation of the blood, which he intends to communicate in a letter to the Royal Society

May 20, 1683
Standard reference information
Collected Letters number: 
Collected Letters volume: 

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 on two octavo pages, written and signed by Leeuwenhoek, is preserved at the Rijksarchief (National Archive) in Den Haag (Inv. No. 13). The letter gives the impression of being part of an ongoing correspondence but it was the first of the twenty surviving letters that he wrote to Heinsius. It was not published during their lifetimes.

Leeuwenhoek wrote this letter to his old friend to recount his recent observations and give a preview of an upcoming letter to the Royal Society. He promised to send Heinsius a copy of the letter, which became Letter L-128 of July 16, 1683 to Christopher Wren.