Back on 7 May I noted the auction of artist Robert Lenkiewicz's library, which included several books found to contain dried, flattened amphibians or reptiles. Emily asked in comments "Does the presence of a dried animal increase the value of the book in which it was found?" ... so I emailed the auction house, Lyon & Trumbull, to try and get an answer. Alex Dove, from the books department (and the discoverer of at least one of the dried frogs) responds:
"We only sold one lot with a frog, Lot 539. I don't believe if had any bearing on the final hammer price of the item. The other frogs/toads were given away to interested clients."
Lot 539, according to the catalogue, is a collection of bound tracts from the 1850s pertaining to fairies and folklore in Durham and the northern counties of England. The description notes "Loosely inserted is a dried and flattened frog." It sold for £300, the upper end of the presale estimate.
And yes, there's a picture.