There's a scene in the finale of The Knick, the Cinemax show about an early-1900s New York hospital, where one of the doctors, Everett Gallinger, enters a room in a mental asylum to which his wife, Eleanor, had recently been committed. He sees something that's possibly even worse than whatever imagery might be conjured by the phrase "early 20th-century insane asylum."
Earlier in the season, the couple's baby daughter died. After Gallinger hastily brought home an abandoned orphan girl to replace her, Eleanor, depressed and seemingly dissociated, drowned the child in an ice bath.
As Gallinger enters the room, Eleanor turns to her husband. Her face is swollen. Her hair is matted. Her mouth is open, black, and vacuous. Her teeth have been pulled by her doctor, Henry Cotton, in order to cure her of "madness." Cotton believes “all mental disorders stem from disease and infection polluting the brain." If the teeth don't fix it, he tells Gallinger, he's next going to remove her tonsils, then her adenoids, and possibly her colon.
It's even creepier that Cotton, played by John "I'm a PC" Hodgman, was a real person, as Wired points out. As medical director of the New Jersey State Lunatic Asylum in Trenton between 1907 and 1930, he routinely practiced what he called "surgical bacteriology," the extracting of potentially diseased parts of the head and body, based on the observation that people who run high fevers sometimes suffer hallucinations.