English: Treatment of diabetes mellitus in 1922 by electrotherapy using a vacuum electrode. In electrotherapy, a quack medical field that fluorished from the 1890s to the 1930s, high voltage alternating current of high frequency from a Tesla coil was applied to the patient's body to treat a variety of ailments. Here the voltage is applied to the patient's stomach with a vacuum (autocondensation) electrode consisting of a metal electrode sealed inside a partially evacuated glass bulb. The electrode is attached by wire to the high voltage terminal of the Tesla coil (left). The high voltage caused the gas in the tube to glow with a dramatic violet color (not visible here), while the glass wall of the tube formed a capacitor with the skin, limiting the current. The voltage was 50,000 to several hundred thousand volts at a frequency of 100 kHz to 2 MHz. This treatment was not painful for the patient because high frequency currents over 10 kHz do not cause the sensation of electric shock. The text says the electrode should be applied to the abdomen and the current turned up as high as the patient can tolerate for 10 minutes, then the electrode should be moved to another spot, until the whole abdomen has been treated. The treatment should be repeated every other day. It claims treatment never fails to lower the blood sugar level o

Caption: Local auto-condensation in Diabetes