The original manuscript on eight quarto pages, written and signed by Leeuwenhoek, is preserved at the Royal Society (MS. 2093. L 4. 42).
Leeuwenhoek's self-publications are the source for the summaries of his 165 letters self-published and thus self-numbered letters. This letter was not among them.
Of the letters from April 4, 1702 (AB 237) through June 10, 1712 (AB 294), those letters with scientific observations, including this one, were all addressed to members of the Royal Society and almost all of them were excerpted in Philosophical Transactions.
The letter was read during the meeting of the Royal Society on April 3, 1712 0.S. (Royal Society, Journal Book Original, vol. II, p. 281).
English translation of the letter by John Chamberlayne was published in no. 334 of Philosophical Transactions for April, May and June 1712, pp. 438-446.
The manuscript of the translation on ten folio pages is preserved in London Royal Society (MS 2094, L.4.43).
Observations on the seminal vessels, the muscle fibres, and the epidermis of a whale.
