The incident Mark Coburn mentions is in chapter 8 of the _Autobiography_:

We had been in a drenching perspiration and Tom's bath was a disaster for
him.  He took to his bed, sick, and had a procession of diseases.  The
closing one was scarlet fever and he came out of it stone deaf.  Within a
year or two speech departed, of course. But some years later he was taught
to talk, after a fashion--one couldn't always make out what he was trying
to say.  Of course he could not modulate his voice, since he couldn't hear
himself talk.   When he supposed he was talking low and confidentially,
you could hear him in Illinois.

Four years ago I was invited by the University of Missouri to come out
there and receive the honorary degree of L.L. D. I took that opportunity
to spend a week in Hannibal--a city now, a village in my day.  It had been
fifty-five years since Tom Nash and I had had that adventure.  When I was
at the railway station ready to leave Hannibal, there was a great crowd
of citizens there.  I saw Tom Nash approaching me across a vacant space
and I walked toward him, for I recognized him at once.  He was old and
whiteheaded, but the boy of fifteen was still visible in him.  He came up
to me, made a trumpet of his hands at my ear, nodded his head toward the
citizens and said confidentially--in a yell like a fog horn--"Same damned
fools, Sam."

Donna Campbell
Gonzaga University