There's more than one person quoted--did you have something specific in mind? For instance, Marshal Neil's last words are quoted, but Twain also makes reference to Daniel Webster, Napoleon, John Quincy Adams, and a number of others.
If you read the piece at a site called online-literature dot com , one thing you will notice is that every single name quoted is highlighted, which makes it very easy to figure out who is being referred to. Good luck!