Definition of "good form"

When any of his descendants chose to take him to task for the crudeness of his manners he was accustomed to look them coldly over and retort that things had come to a pretty pass when comparatively new people ventured to instruct the oldest of the old settlers as to what was or was not good form.

1909, John Kendrick Bangs, chapter 3, in The Autobiography of Methuselah