Gregg,

The full quote reads as follows:

    ``You perceive I generalize with intrepidity from single
    instances. It is the tourists' custom. When I see a man jump
    from the Vendome Column I say, 'They like to do that in
    Paris.'''

It appears in _Mark Twain's Notebooks & Journals, Vol. II._ page 318. Also
in Paine, Chapter 121 (Vol. II), page 644.

Kevin B.