The mechanism consists of a pear-shaped metal body divided into spoon-like segments that can be spread apart with a spring or by turning a key.
At least one of the older devices is held closed with a cap at the end, suggesting it could not have been opened after inserting it into an orifice without actively holding it shut.
There is no contemporary evidence of such a torture device existing in the medieval era, and ultimately the utility of any genuine pears of anguish remains unknown.
However, through the design of the devices, such as metal consistency and style, a select few are thought to have been made in the early modern period (circa 1600).
"[6] Another mention is found in Brewer's Dictionary of Phrase and Fable (1898), which claims that "robbers in Holland at one time made use of a piece of iron in the shape of a pear, which they forced into the mouth of their victim.
That connection having been made, all subsequent sources agreed, and before long a sham industry was established which simultaneously fed off and reinforced the hypothesis by fabricating and retailing new "artifacts".
One could imagine them as surgical instruments - some sort of speculum perhaps, or a device for levering open the mouth in order that a dentist might operate.
A footnote in the book says: “This poire d’angoisse was a famous gag, in the form of a pear, which, being thrust into the mouth, by the aid of a spring, dilated, so as to distend the jaws to their greatest width.” Though there is little or no evidence of its use, there are a number of extant examples of variously crude, ornate, and elaborate, pear-shaped devices with three or four leaves or lobes, driven by turning a key that rotates the central screw thread, which spreads or closes the leaves.