At the start of Our Mutual Friend, Charles Dickens has Eugene Wrayburn refer to "our friend who long lived on rice-pudding and isinglass", the implication being that this was a poor diet. We are left in some doubt, however, for Dickens never mentions either rice puddings or isinglass again, and the only other people mentioning it are either quoting it or explaining what it meant.
In Oklahoma!, isinglass is the stuff of which curtains are made, so it must surely be bad for the digestion.
This raises the question, though, when Rodgers and Hammerstein have Curly, their hero sing in Oklahoma! of "isinglass curtains you can roll right down — in case there's a change in the weather", what sort of isinglass does he mean — the mica mineral type, or the gelatin fishguts type?
Does this wine taste fishy to you?