George Garden wrote Letter L-227 to Leeuwenhoek about the role of egg and ovaries in reproduction
This letter is known only by its inclusion in Leeuwenhoek's Letter L-240 of 19 March 1694 to the members of the Royal Society. It is not numbered there as a separate letter. The date is New Style, which was ten days ahead of the Old Style date of 24 August 1693 used by Garden in London.
Text of the letter in Alle de Brieven / The Collected Letters at the DBNL - De Digitale Bibliotheek voor de Nederlandse Letteren. Leeuwenhoek included it so that he could argue against it.
George Garden (1649–1733) was a clergyman from Aberdeen, Scotland, and supporter of Antoinette Bourignon (1616-1680), the French-Flemish mystic who had also enthralled Johannes Swammerdam.
Garden argued that the egg and the ovaries play an important part in reproduction.
It was Leeuwenhoek's position that that the ovaries have no meaning because the uterus is the matrix of the male seed. Leeuwenhoek thinks that the ovaries correspond to the testicles in men, in whom, on the other hand, the nipples and breasts have no meaning.
Leeuwenhoek ended the March 1694 letter with a quotation from a February 1694 letter from "B.H." from Amsterdam. This was Leeuwenhoek's friend from Delft, Benedictus Haan, by then living in Amsterdam, who agreed with Leeuwenhoek's position.
Letter L-240 of 19 March 1694
If you combine all these considerations: that a little animal cannot be generated without a nest of its own or a cicatricula, that there have been various foetuses outside the Uterus and that there is no ascent to the Uterus for a considerable time after conception, these things appear to demonstrate clearly that animals cannot be formed from animalcules without Eggs from females.