Dried swim bladders of fish? Gag me with a spoon!
Found the old measurements:
1 wine glass = ¼ cup/2 ounces
1 jigger = 1.5 fluid ounces
1 gill = ½ cup/4 ounces (or 5 in the UK, generally)
1 teacup = a scant ¾ cup/almost 6 ounces
1 coffee cup = a scant cup/almost 8 ounces
1 tumbler = 1 cup/8 ounces
1 pint = 2 cups/16 ounces
1 quart = 4 cups/32 ounces
Oh, isinglass isn’t all that bad. It was the first material used as roll-up “windows” in open carriages and buggies.