In the late 1800s, we still didn't know a great deal about electricity. One scientist was still attempting to figure out how electric shocks kill things in 1895, and found that when he delivered a 240-milliamp shock to dogs, their hearts were very damaged (for comparison, a taser puts out about 3 milliamps). In 1903, Thomas Edison was trying to prove alternating current was dangerous by electrocuting animals. But before these instances of using electricity for death, one inventor thought people would be interested in using quick jolts to improve health, like the green juice of his day. "When electricity was in its infancy, the power was believed to have a beneficial effect on health. Why not vend a small measure of electricity by coin operation?" wrote Paul Braithwaite in his book, Arcades and Slot Machines. Braithwaite was describing an existing patented design: a coin-operated vending machine that would deliver an electrical shock to the customer in exchange for money. The patent for a "coin operated electrical apparatus" was originally filed by Norman W. Russ and granted in England in 1886. Russ followed up with patents for his invention in France, Belgium, Canada, and the United States, which granted it on May 15, 1888. via Ars Technica.