Kirlian photography refers to a form of photogram made with a high voltage. It is named after Semyon Kirlian, who in 1939 accidentally discovered that if an object on a photographic plate is connected to a source of high voltage, small corona discharges (created by the strong electric field at the edges of the object) create an image on the photographic plate. See wiki for detail.
Robert Buelteman the author of the photos presented in this blog. Use his elaborate extension of Kirlian photography – works indoors in total darkness, forsaking cameras, lenses, and computers for jumper cables, fiber optics, and 80,000 volts of electricity. The whole process is so tricky that each image can take up to 150 attempts. (@_@ is there any easy and safe way to do that? Can we achieve that by Photoshop special effect?) Anyway, those pictures are really amazing. And if you want to see more, click here to visit his website.