Mark Twain said that there were only 100 jokes ever created, and that we were just changing the names and reusing them. I've heard the same Polock jokes redone as Sven and Olie, or Pat and Mike versions. Similar for whatever race is being demeaned by another. I'll lay odds that many of those old jokes were old long before Vaudeville. Years ago, when we'd get road shows or conferences in our theater, I'd get a dozen new jokes. The last 20 years, due to the PC culture, those jokes dried up. The humor that used to be passed around on copiers turned into memes and are now passed on digitally. I figured Xerox had a team of comics and artists creating those bad jokes---the art was always the same as was the humor, and half of the stuff printed on office copiers was comedy.