Catalog, illustrated wraps, 6 x 9, 52 pp. Vi Rex Electric Company, Chicago, 1921.
Wonderfully illustrated catalog with various violet rays machines, along with testimonials, illnesses cured, etc.
In the early 20th century, the "violet ray" was a popular electrotherapy device promoted as a cure-all for various ailments, though now considered a form of medical quackery.  Manufacturers boasted that these machines could treat a vast array of conditions, from baldness and acne to more serious issues.  In the late 1940s and 1950s, lawsuits against manufacturers for making false claims and even for hazardous use due to inadequate instructions, lead to the destruction of many machines. Violet ray devices utilized Nikola Tesla's invention of the Tesla coil and the growing knowledge of alternating electrical currents to produce a high voltage, high frequency, and low current electrical discharge. This discharge, passing through a glass electrode containing a gas like argon, created the characteristic violet glow. The electrical discharge, heat, and ozone generated were then applied to various parts of the body using different shaped electrodes.  Though the violet ray device was a fascinating piece of early electrical technology, its widespread marketing as a cure-all for almost every ailment placed it firmly in the category of quack medicine.
Front cover mostly detached;  some light expected edge wear. Front cover retains vibrant colors, internally sound with no torn or missing pages.