Perkins Metallic Tractors

device · 1796–1810

category:device

delivery:Two short metal rods, each three to four inches in length, of a claimed special alloy (one of a yellow metal, one of a white metal). The operator drew the points of the rods lightly across the surface of the patient's body over the affected area for approximately twenty minutes per session, with the claim that the metallic action drew out a noxious electrical fluid responsible for pain, paralysis, inflammation, rheumatism, gout, and a range of other conditions. Sessions were performed by the patient or by a domestic attendant after instruction; the device was a self-administered or family-administered article rather than a practitioner-administered one. The pair retailed for five guineas (approximately the equivalent of two months' wages for a skilled artisan), several times the cost of materials.

price tier:elite

era:1796–1810

current status:historical

regulatory:withdrawn

SHORT PITCH (AS SOLD)

A pair of patented metal tractors, of a special alloy, that draw out the noxious electrical fluid at the root of pain, paralysis, rheumatism, gout, and inflammation when applied lightly to the affected body part.

THE ACTUAL EVIDENCE

No controlled outcome data were ever published in support of the tractors. The published testimonial literature (most prominently Benjamin Douglas Perkins's *Influence of Metallic Tractors on the Human Body*, London, 1798) consisted of unblinded patient self-reports collected by the practitioner and the practitioner's family. In January 1799, John Haygarth at Bath General Hospital and Richard Smith at Bristol Royal Infirmary independently tested 'fictitious' wooden tractors carved to resemble the patented Perkins device on five chronic patients, and reported that the wooden imitations produced the same reported relief at no cost. Haygarth published the result in 1800 (*Of the Imagination as a Cause and as a Cure of Disorders of the Body*). The fictitious-tractor experiment is the founding placebo-controlled trial in the modern Anglophone medical literature; the tractors are its founding disconfirmation. The metallic-alloy mechanism is empirically empty; the special alloy was not in fact special and could be reproduced in ordinary brass and iron with no change in reported clinical effect.

PRACTITIONERS

Elisha Perkins

INGREDIENTS

Perkins 'special metallic alloy' (claimed)

CASES

perkins-tractors-1796-1810

CLAIMS

The Perkins Metallic Tractors, drawn across the skin over an affected body part for approximately twenty minutes, relieve rheumatism, gout, paralysis, inflammation, and a range of other chronic conditions through the metallic drawing-out of a noxious electrical fluid responsible for the underlying disease. refuted
Fictitious tractors of wood, carved to resemble the patented Perkins metallic pair, produce the same patient-reported relief as the original metallic device when applied under matched conditions, demonstrating that the reported therapeutic effects of the Perkins Tractor are attributable to imagination, expectation, and the ceremonial structure of the application rather than to any property of the metal. replicated
Imagination and expectation can produce not only the relief of symptoms reported by satisfied patients but also the worsening of symptoms in a small number of patients to whom the same fictitious treatment is applied, demonstrating that the placebo phenomenon is bidirectional and that the same psychological mechanism that produces a reported cure can also produce a reported harm. replicated

SOURCES

NOTES

The Perkins Metallic Tractors (United States patent granted to Elisha Perkins in 1796) are a pair of pointed metal rods of a claimed special alloy, retailed at five guineas per pair, drawn over the skin to relieve pain, paralysis, and a range of chronic conditions through the operator’s redirection of a proposed noxious electrical fluid. The intervention is the structural prototype of patented-device elite quackery (the device is patented, the alloy is proprietary, the testimonials are practitioner-collected, the cost is several months’ wages for an artisan and trivial for an elite household) and was disconfirmed within three years of its patent by Haygarth’s January 1799 fictitious-tractor experiment at Bath General Hospital. The category device is used here rather than regimen because the patent itself was for the physical object, not for a practice or protocol; the practice of tractor-drawing followed from the device.