Hey Physiobob that is one hell of a site! The illustrations are great!
Graham R, the Faradic machine was in use in the profession even during the the 1980's. I was trained to use it - the unit was a bit more automated than the coke bottle plunger variety but it basically did the same thing. the plunger was of course the induction coil and why the machine was named after one of the greatest physisicists and chemists, Michael Faraday.
It was actually a very useful piece of equipment for eliciting a muscle contraction although it hurt like hell. I still have a scar on my thigh from where a fellow student gave me an electrical burn while we were practising on each other.
Eventually the new battery-powered neuromuscular stimulators replaced the Faradic unit as the current was safer and more comfortable and you could do more fancy things with these little units like sequence a number of muscles to contract.