The Theronoid, a curative electromagnetic solenoid, is a clone of Gaylord Wilshire’s equally famous “I-on-a-co” body coil. In 1928, the year following Wilshire’s death, Philip Ilsey, manager of the Cleveland office of I-on-a-co, started his own company to produce the Theronoid. It consists of an 18 inch coil of several hundred feet of insulated wire covered with simulated leather, which gave rise to its nickname, the “magic horse collar”. A nickel plated control box mounted on the belt has an on/off and a high/low toggle switch. In use, the coil was placed around the body and plugged into the house current for 3 to 5 ten minute treatments each day. It was claimed that all diseases could be cured by the Theronoid, and many testimonials were printed in the Theronoid Health News, covering virtually all maladies from constipation to paralysis.
An important accessory to the theronoid was a smaller coil wired to a flashlight bulb. When this coil was held near the theronoid, and parallel to the larger coil, the bulb would light. This simple demonstration of induction must have impressed those unfamiliar with the rudiments of electricity. That the Theronoid could cause a light bulb to glow that was not connected to anything was, for many, sufficient proof of its curative power, and made up for its shortcoming of having no moving parts, no tubes, and emitting no light or heat, or shocks.