The late Joseph Jefferson gave the following account of the origin of the term, and this explanation may be relied upon, for the famous actor was an excellent authority on subjects on which he spoke and wrote:
In an old melodrama by William Dillon, called “The Broken Sword,” are two parts—Count Xavier and his servant Pablo. The Count is a sort of Münchausen, fond of telling stories of his exploits. He tells one:
“Once I entered the forests of Colloway, when suddenly, from the boughs of a cork-tree——’
“Chestnut, count,” interrupted Pablo.
“Cork-tree,” said the count.
“A chestnut,” reiterated Pablo. “I should know as well as you, for I have heard you tell the story twenty-seven times.”
William Warren, who had played Pablo often, was at a men’s dinner once when a gentleman told a story whose age and originality were far beyond any doubt.
“Chestnut,” murmured Warren. “I should know as well as you, for I have heard you tell it twenty-seven times.”
The guests took up the expression, and from that I believe comes the origin of the term.