Perkins's patent metallic "Tractors": Development, adoption, and early dissemination of an eighteenth-century therapeutic fad.

The metallick Tractors were patented by Elisha Perkins, a Connecticut physician, in 1796, for the treatment of various ailments, particularly those associated with pain. They were subsequently rapidly and widely disseminated on the basis of testimonials and aggressive marketing tactics. Dissemination was facilitated by endorsements from prominent physicians, politicians, and clergy, by quasi-theoretical explanations of efficacy based on then-current experiments of Galvani and others, and by the apparent simplicity and safety of the procedure. Abandonment of this ineffective therapy was later prompted by the application of blinded placebo-controlled trials using sham devices.