Wrote Letter L-444 of 1706-03-07 to Govert Bidloo to follow up on his visit earlier that day about what Leeuwenhoek discovered in the intestines they had viewed
Listing of the letter in Alle de Brieven. The Collected Letters at the DBNL - De Digitale Bibliotheek voor de Nederlandse Letteren
This letter is known only by reference in Letter L-447 of 20 April 1706 to the Royal Society
When the said Mr. Bidloo left, I was requested to let him know soon if I should discover some other things in the piece of intestine we were viewing.
Hereupon I wrote on the evening of the said day that I had considered whether the fat particles we saw are not taken by many people to be small glands, and that this also takes place in the skin, because in the skin and the intestines of animals I have not seen small glands, which many people speak of, but large numbers of fat particles.
Leeuwenhoek quoted and summarized his letter to Bidloo about the structure of the intestinal wall of a little piece of the colon deriving from a woman who had been hanged.