The so-called “Tin Transplant” is the process by which Winkie tinsmiths transplant the heart of an elderly or infirm individual into the vessel of a tin-plated automaton.
The procedure, first completed on the beloved but cursed woodsman Nick Chopper, is most successful when the heart of the individual in question is pure and kind. But that hasn’t stopped death-fearing ne’er-do-wells throughout Eden from trying to steal the technology for themselves.
Though Winkie tinsmiths had been providing prostheses for amputees since time immemorial, it wasn’t until Nick Chopper was cursed by The Witch of the East that they conceived the idea of a full-body replacement.
Once poor old Nick had chopped off the last of his original limbs and there was naught left of his “meat body” but his gentle heart, Winkie smiths realized that the piecemeal work they’d been doing could be done all at once to save those whose bodies were failing them more rapidly.
However, the Winkies soon realized that only those possessed of the kindest souls were good candidates for the procedure. The transplant of impure hearts resulted, time after time, in the creation of beings who were twisted and evil.
To prevent such calamitous results in the future, a rigorous purity test was developed to screen candidates for the procedure—a development widely protested throughout Oz and the rest of Eden. After all, who were the Winkies to decide who deserved immortality and who did not?