Deidre:

One note regarding Huck Finn that might ease some of your (and your
students' ) qualms regarding Twain's use of the "n-wprd" (n-word,
my terminal doesn't allow backspacing):

According to several sources in the _Mark Twain Journal_ issue
featuring African-American scholars' appraisal of _HF_ on its
centennial, the epithet "Nigger Jim" is an invention of Paine's,
appearing first in his _Biography_.

But as one scholar wrote, the n-word struck a chord with whites and
was retained.  Hemingway was the foremost example of this-he picked
up the epithet and never dropped it when referring to Jim.

If you wish, I'll get the exact references for yoyu.

Robert Dagnall