That reminds me of how, in A Christmas Carol, Dickens describes a ghost glowing like "a bad lobster in a dark cellar". Some modern people think Dickens was just

That reminds me of how, in A Christmas Carol, Dickens describes a ghost glowing like "a bad lobster in a dark cellar". Some modern people think Dickens was just being surreal, but there was a real meaning to this. Before refrigeration, people would keep meat and seafood in the cellar as was cooler than elsewhere. But not cool enough and things would rot after a couple of days. One of the bacteria that rots seafood is Vibrio, which often has genes for luminescence. So you could see if seafood had gone off if it glowed.