Henry Oldenburg wrote to Leeuwenhoek requesting that he examine saliva, chyle, sweat, and sperm

April 24, 1674

Leeuwenhoek mentioned it in his Letter 4 of 1674-06-01. In Letter 5 of 1674-07-06, he examined saliva, chyle, sweat, etc., as Oldenburg had requested.

Leeuwenhoek again mentioned it in his Letter 22 of 1677-11-01 to William Brouncker. We have only the Latin translation of that letter, in which Leeuwenhoek reports his observations of human sperm, as Oldenburg had requested.


The manuscript is missing; this letter was never printed.