Perkins 'special metallic alloy' (claimed)
mineral
MECHANISM CLAIMED
A proprietary alloy of yellow and white metals, when drawn across the skin, produces a tractive electrical action that draws out the noxious fluid at the root of pain, paralysis, rheumatism, gout, inflammation, and a range of other chronic conditions. The therapeutic action is proposed to depend on the specific alloy composition; ordinary metals would not produce the effect.
MECHANISM ACTUAL
The published 1799 disconfirmation experiments (Haygarth at Bath; Smith at Bristol) demonstrated that fictitious wooden tractors carved to resemble the patented metallic pair produced the same patient-reported relief. The mechanism is empirically empty. The patient response is a placebo effect attributable to imagination, expectation, and the ceremonial structure of the application. Subsequent independent inspections of original Perkins tractors that survive in research collections (notably at the Wellcome Collection, London, and the Yale Medical Historical Library) confirm that the actual alloys are ordinary brass and steel.
INTERVENTIONS USING IT
NOTES
The ‘special metallic alloy’ of the Perkins Tractors is the founding type-specimen of the proprietary-mechanism cover that recurs across the archive: a commercial intervention is sold on the proposition that its therapeutic action depends on a proprietary substance, the substance is not in fact what it is claimed to be, and the practitioner-vendor’s revenue stream depends on the customer’s inability to verify the underlying material. Provenance is encoded as mineral because both component rods are ordinary metals; no electrical, biological, or radiative property attaches to the materials beyond what any small brass or steel rod would display.