English: Time exposure photo of a student conducting a discharge through his body from a Tesla coil, of a type known at the time as an Oudin coil, at Los Angeles Polytechnic High School around 1909. The arcs are 16 inches (41 cm) long, corresponding to a voltage of around 200kV. The subject doesn't feel a shock and is apparently unharmed. It was believed until recently that this was due to skin effect: the high frequency current doesn't penetrate into the body but travels along the skin, so it cannot cause electrocution, only skin burns. The student uses a metal rod to avoid skin burns. However, it is now thought that Tesla coil discharges can travel through the interior of the body, causing damage, and the subject doesn't feel a shock because the nerve cells are not sensitive to these high frequency currents. Therefore THIS EXPERIMENT IS EXTREMELY DANGEROUS AND CAN RESULT IN ELECTROCUTION. DON'T TRY IT. Alterations to image: removed caption, which read: "Taking a 16 inch discharge into the body from the Oudin resonator. Exposed 10 seconds."