Steve's suggestion that the American practice of tipping bartenders
probably dates from urban saloons of the late nineteenth-century makes
sense.  These saloons did promote & elect local politicians (with the
"saloon vote") and these politicians might be inclined to do favors for
the preferred customers w/ the good sense to keep the bartenders happy,
so we can see the incentive to tip there.
 
(It also offers a potential explanation of the popular observation, common
in Iowa City foodservice circles, that rural Midwesterners tip awkwardly
and insufficiently.)
 
Steve's theory also fits well with my failure to find any references to
tips in the antebellum temperance literature I've been working with
lately.  Even in the coldest of money-saving arguments, temperance
advocates fail to score points by provoking outrage over the "hidden"
expense of the tip.  Any bartender today would tell you such arguments are
clearly perceived by the many who can afford six pints of Leinie's, or
four glasses of Bombay Sapphire Gin & tonic, but can't afford to tip.
Most taverns in temperance novels are Pop & Mom operations which overlook
the financial needs of their degenerate offspring who fetch the grog.
 
On the other hand this explanation does not consider the relationship
between tipping bartenders and tipping bellhops, waitresses, cabbies,
hairdressers, pizza boys and even the guy who tattoos you.  These
practices are popularly considered as of a piece, too.  Any history of the
service industry would have to look to the village tavern as the precursor
of the hotel, the restaurant, the (stage)  dispatcher, etc., so we'd have
to wonder if waitresses get tipped today because bartenders got tipped in
late C19 Chicago, or if bartenders get tipped today because somewhere
along the line the position was granted the "dignity" (?) of other service
occupations.  Was tipping ever invented?
 
Also, the London bartenders I knew while living there were working for
room and board, and gave me the impression that most bartenders have
such an arrangement and consider it sufficient compensation.
 
Jon
Iowa City