In 1895, through the genius of Nikola Tesla, the Niagara Falls Power Company began sending alternating current (AC) to Buffalo, New York, twenty-five miles away. Cities throughout the world followed suit and made commercial AC power available to the general public, even miles from the power generating station. As a result, Tesla’s high voltage loop devices, which were powered by AC, started to become widely known and applied.
In 1898, Tesla published a paper that he read at the eighth annual meeting of the American Electro-Therapeutic Association in Buffalo, New York. He states that one of the early observed and remarkable features of pulsed magnetism was its apparent harmlessness, which made it possible to pass relatively great amounts of electrical energy through the body of a person. Loops up to three feet in diameter were used for magnetically treating the body without contact, though ten to a hundred thousand volts were present "between the first and last turn.” Tesla concludes that bodily "tissues are condensers" in the 1898 paper, which is the basic component (dielectric) for an equivalent circuit only recently developed for the human body. In fact, the relative permittivity for tissue at any frequency from ELF (10 Hz-100 Hz) through RF (10 kHz-100 MHz) exceeds most commercially available dielectrics on the market.
This unique property of the human body indicates an inherent adaptation and perhaps innate compatibility toward the presence of high voltage electric fields, probably due to the high transmembrane potential already present in cellular tissue. Tesla also indicates that the after effect from his loop treatment was certainly beneficial.