Green’s Dictionary of Slang

1. (US) electro-shock therapy, esp. when used in prison.

1975		S.J. Sansweet Punishment Cure 155: I have seen shock treatment — called ‘Edison Medicine’ by prisoners — used as punishment .
1979		A.S. Blumberg Criminal Justice 328: More likely, treatment will consist of [...] such tortures as electroshock treatments (‘Edison Medicine’).
1980		J.B. Robitscher Powers of Psychiatry 301: Electroconvulsive shock therapy in prison hospital wards and in hospitals for the criminally insane has been used as a punishment; prisoners call the electroshock machine ‘Edison medicine’.
1990		S. Morgan Homeboy 43: By now Rooski loved Edison medicine better than LSD.
1997		T. Powers Faultlines 503: That was ECT [...] electroconvulsive therapy—shock treatment, Edison Medicine.

2. judicial execution via the electric chair.

1997		S.J. Cannell Final Victim 59: California stopped dispensing lethal doses of Edison-Medicine and began killing its condemned with the far more humane lethal injection.
2006		Angolite (Lousiana State Pen.) 31 37: Using the AC dynamo, the strange looking chair — later called in some states ‘Edison’s Medicine’ — was installed in New York's death chamber in 1889.