"drink laced with chloral hydrate," by 1918. Mickey Finn was used from the 1880s as the name of the main character in a series of popular humorous Irish-American stories published by New York Sun staff writer Ernest Jarrold (1848-1912), who sometimes also used it as his pen-name. Perhaps there is a connection.
Michelin
Michelson-Morley
Michigan
mick
mickey
Mickey Finn
Mickey Mouse
mickle
Micmac
micro-
microbe