Visited by Govert Bidloo
In the Letter L-447 of 20 April 1706, Leeuwenhoek wrote to the members of the Royal Society about Govert Bidloo (detail on right from portrait at age 35 by Gerard de Lairesse), a fellow member of the Royal Society as well as a colleague in Delft.
Professor Bidloo came to my house on the 7th of March, with the request that we should view a piece of an intestine (with the addition that it was an intestine of a woman) through my magnifying glass, and while a small piece of an intestine was separated by me from a larger piece, we saw in one of the thin membranes of which the intestine partly consisted a great many little fibres and small vessels, a large number of which lay through and over each other, and some fat particles, which lay on each other in some places in the form of grapes.
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.
That evening, Leeuwenhoek responded to Bidloo, noting the woman's blood outside the intestine's blood vessels. That observation led Leeuwenhoek to conclude that she had died by hanging, which turned out to be correct.
