This is a strange little story. It's clever and well told, but it is odd that Mark Twain holds up the abolitionists as a violent, secretive group -- terrorists, really. John Brown, alone among abolitionists, attacked slavery with a violence equal to that of slavery, itself. The rest of the abolitionists, almost universally, used non-violent means to undermine slavery. Yet, here in this story they are painted with the trappings and methods of the Klan. Mark Twain came a long way in his understanding of race, from a family that participated in the institution of slavery to a brilliant critic of it; it's possible this story simply reflects the overwhelming bias against the abolitionists from the time of his youth. I just produced an audio version of the story at http://stuffyoushouldread.com/a-scrap-of-curious-history-an-audio-extra/ if you'd like to take a listen. Either way, I consider this a near miss for Twain.