Anne certainly thinks that the incident on Wednesday, 10 May, 1944 is "a scream" (231). While studying French, Anne hears some dripping sounds behind her and she asks Peter what they might be. Peter doesn't even answer her because he runs up the stairs too quickly. Apparently, Mouschi has chosen to relieve himself in some wood shavings rather than in his litter box. The urine splashes on potatoes, books, and socks while also leaving behind a notable stench. Peter acts very responsibly by cleaning up after his cat, but it does cause some running around in the process. Anne notices that Mouschi must have known that he had done something wrong because he hides under a chair while Peter cleans up after him. It's hard to tell which part of the scene Anne laughs at most: Peter running around so quickly to clean up after his cat, or the cat's funny behavior.

On Wednesday, 10 May 1944, Anne describes an incident where Mouschi the cat missed his "litter box" in the loft above the attic.  The puddle he made dripped through the holes in the attic ceiling, landing just next to and in a barrel of potatoes, and also through the attic floor "into the dining room between a pile of stockings and some books, which were lying on the table".  Peter tried valiantly to clean the mess "with water, bleaching powder, and floor cloth while Van Daan diplomatically sought to "soothe everyone".  Everything was soon set to rights, although, as Anne puts it, "it's a well-known fact that cats' puddles positively stink (and) the potatoes proved that only too clearly".