Your Etiquette Advice from Some Old Books I Found

Today's etiquette advice comes from American Etiquette and Rules of Politeness 1884 (Rand, McNally & Co.):

DO NOT CONTRADICT It is extremely impolite to directly contradict any one. If the matter is of no importance, let it pass; otherwise, say, "I beg your pardon, but I think you are mistaken or misinformed," or any other similar phrase, which will break the weight of direct contradiction.

This has been your etiquette advice from some old books I found.