In response to Camy's question:

In his AROUND THE WORLD WITH MARK TWAIN, Robert Cooper
reports (pp. 226-227) that on February 7, 1896, Twain
arrived in Calcutta and, despite having a cold and
despite suffering from carbuncles, he received two
reporters. After discussing racial matters in England
& the colonies, as well as comparing Canadian &
American treatment of "Red men," Cooper says Twain
talked about Negroes, comparing them to Indians,
asserting that American Negroes, "are merely freed
slaves, and you can't get rid of the effects of
slavery in one or even two generations.  But things
will right themselves.  We have given the negro the
vote, and he must keep it."

Then Cooper says of Twain:
"There was not, he said in response to a question, the
slightest likelihood of intermarriage. 'The white and
the black populations, however, will in time learn to
tolerate each other and work harmoniously for the
common good.  They will co-exist very much as the
different races in India have done for centuries.'"

There's more on Twain and race on Cooper's pages
226-227, but the paragraph above comes as closely to
addressing Camy's question as anything I've found.

Cheers, Cal