Victorian musical slang for household creepy-crawlies – B Flats for bugs and F Sharps for fleas. Maybe they’re musical terms because you make a noise if you’re bitten? Or maybe it was just being funny. It does sound quite a music hall-y kind of thing.
I like that the word “Foxed” on the second page is included. It (still) means brown marks that develop on old books and the page itself is an illustration of it.
