Origin of "Slipped him a mickie"?!

Origin of "Slipped him a mickie"?

The Mickey Finn is reputedly named for the owner and bartender of a Chicago establishment, the Lone Star Saloon and Palm Garden Restaurant, which operated from 1896 to 1903 in the city's South Loop neighborhood on the west side of South State Street north of Harrison Street. This part of State Street was then known as "Whiskey Row". Before his days as a saloon proprietor, Mickey Finn was known as a pickpocket and thief who often preyed on drunken bar patrons.