"The twelfth finger of the left hand but one" is a "Dead-Sea Phantasm and gibbering Spectre of Unveracity," an "extravagant and hyperbolical declamation" that is deliberately enigmatical so as to "stimulate curiousity, quicken the reflective faculties, and provide the studious public with fresh materials for innocent conjecture." A spoof of a poem by Swinburne is offered as explanation:
Before the beginning of years,
There came to the making of Fun,
Jest, with its jocund jeers,
Pleasure and pointed Pun;
Quip and Conundrum quaint;
Cheerful and jubilant Chaff;
Humour, to tickle a saint
With her lisping lyrical laugh;
And they worked at the woof and the weft,
And they pointed, when all was done,
With a Finger—the Twelfth—of the Left,
Of the Left, Left Hand—but One!
(From an 1865 issue of Fun magazine.)