Twain does by way of insinuation and implication discuss and define being sold down the river in PUDD'NHEAD WILSON. The character Roxana does react to the threat of being sold down the river by Percy Driscoll. He says: "I will sell you DOWN THE RIVER!" The narrative continues, "It was equivalent to condemning them to hell! No Missouri negro doubted this. Roxy reeled in her tracks and the color vanished out of her face; the others dropped to their knees as if they had been shot; tears gushed from their eyes, their supplicating hands went up, and the three answers came in the one instant . . . " (12) In the following chapter (Chapter 3), Roxy agonizes over the terror of the threat of being sold down the river. And she subsequently makes the switch of the babies . Also, later in the book in Chapter 16, her son "Tom" does "forge a bill of sale and [sells] his mother to an Arkansas cotton planter for a trifle over six hundred dollars. He did not want to commit this treachery, but luck threw the man his way and this saved him the necessity of going up country to hunt up a purchaser" (81). In the same paragraph Twain goes on to discuss some of the implications of being sold down the river. He equates it with such "treachery as . . . treason to a mother" (81). I'm sure it's also discussed in the same indirect way in HUCK FINN as well, possibly even in TOM SAWYER--but never directly. Of course, that wasn't Twain's way. He was most effective because of the implications and irony of the situations in which he placed his characters. You may also want to look in some of the Slave Narratives, such as by Harriet Jacobs or Frederick Douglass. I know when I have taught PUDD'NHEAD and the slave narratives, there are many parallels. Hope this helps, Carolyn Richey SDSU PS: The quotes are from the Norton Critical Edition