To anyone who loves cats, this is a diabolical idea - whether or not it was ever put into practice. The katzenklavier (cat piano) was a keyboard to which 7 to 9 cats, in order of the pitch of their voices, were fastened. Pressing a key caused a sharp nail to be driven into the corresponding animal's tail, causing it to cry out. The idea is ascribed to the fertile imagination of German Jesuit scholar Athanasius Kircher (1602-1680), who described it as cheering up a depressed Italian royal: "The result was a melody of meows that became more vigorous as the cats became more desperate. Who could not help but laugh at such music?—and so was the prince raised from his melancholy." According to German physician Johann Christian Reil (1759-1813), the device could cure mental patients who had lost the ability to focus: "A fugue played on this instrument - when the ill person is so placed that he cannot miss the expression on their faces and the play of these animals - must bring Lot's wife herself from her fixed state into conscious awareness."
There are apocryphal accounts of such a device - before and after its supposed design by Kircher - being used in 16th c. Brussels and 18th c. Prague. The katzenklavier has been brought into modern consciousness by an award-winning 2009 animated film called "The Cat Piano." The story is told in the form of a poem by director Eddie White, who calls the machine the "harpsichord of harm":
"Confined were the cats in a row of cages.You will not regret spending 8 minutes to watch the film here.
With each note struck upon its ivory tusks,
A sharpened nail would pierce each cat’s tail,
Forcing a note from each pitch on the scale. "