Kirlian or corona discharge photography is a photographic process for the visualization of glowing or corona discharges. The process was developed by the Soviet couple Semjon Kirlian and Valentina Kirliana in 1937.
This type of photography is also used in alternative medicine, because conclusions can be drawn on the electrical conductivity of the body surface. It could be assessed whether energy channels, the meridians, are blocked in the sense of this doctrine.
Hands are mainly photographed (fingertips) and feet (toes), because after the presentation of Traditional Chinese Medicine (TCM) the meridians begin and end according to the acupuncture doctrine on fingertips and toes.
By comparing the photographs of the hands of persons with certain known diseases and the photographs of persons who were not aware of any disease, it is possible to identify alleged disease-typical deviations and thus to use the images diagnostically. Therefore, some naturopaths with the Kirlianfotografie work as a basis for their medical history.
Source: Wikipedia