English: Collection of electrodes used in high frequency electrotherapy, a Victorian era medical therapy in which high voltage radio frequency electricity from a Tesla coil or Oudin coil was applied to the body to treat various ailments. The electrodes plugged into the end of an insulated handle (45) connecting them to a wire from the high voltage terminal of the coil. The electrodes were of two types. The upper instruments consist of a metal point that produced a corona discharge (this was called "effluve") that was played over the patient's body without getting close enough for a spark to jump. The lower electrodes consist of a metal terminal sealed inside a partially evacuated glass tube of various shapes. These were used for contact therapy and within the patient's body through the mouth, vagina or anus. The high voltage ionized the gas in the tube, allowing the RF current to flow through the gas and through the glass wall of the tube into the patient's body. The patient usually held a metal electrode attached to ground to provide a return path for the currents.