The Man Who Changed His Mind (1936)

Starring Boris Karloff, John Loder, Anna Lee, Frank Cellier, Donald Calthrop
Directed by Robert Stevenson

(actor & director credits courtesy IMDB.com)

A scientist mocked for his theories, takes in a young female assistant, who helps him prove that he can switch the brain of one creature to another, but she fears he's too eager to experiment on man. 

This is one of Karloff's first "mad doctor" films, predating the series he made in America for Columbia, and it may well be the best of them, with good performances and fine photography by Jack Cox.  Karloff made this for Gaumont-British and Gainsborough, and their production values are excellent, with cleverly designed machines for Karloff to operate.  Calthrop was a favorite performer for me, a wheelchairbound patient who delivers many witty and denigrating asides, and also Cellier whose performance as a stuffed shirt gives way to another different role to play.  Karloff himself gives a worthy portrayal, riveting to watch, as his frustration gives way to surrendering to evil in tightly-framed closeups.  We have here a very good horror film, among the top entries of the era.      

Bedlam (1946)

Starring Boris Karloff, Anna Lee, Billy House, Richard Fraser, Glen Vernon
Directed by Mark Robson
(actor & director credits courtesy IMDB.com)

In 18th century England, a cruel and vindictive man runs an asylum for the insane, and maneuvers an intelligent and sharp-tongued lady who scorns him into being committed there. 

Karloff stars as Master Sims, the operator of the asylum known as "Bedlam" in this fine period drama from producer Val Lewton.  He and co-star Lee, who both give excellent performances, are gifted with a fine script from Robson & Lewton, giving them poetic dialogue befitting the lords and ladies of the period.  Lee's character of Nell Bowen, the protege of a powerful lord, who loses her position and her freedom, is very unlike most leading ladies of cinema in her frankness and her independence, and is a favorite of my friend Dominique Lammsies, who calls her a memorable anti-heroine of cinema.  The scenes within the asylum, in which Bowen encounters the poorly cared for inmates are well done, with many of the patients clearly misunderstood by the standards of the time, and well-acted by the likes of Ian Wolfe, Jason Robards, Joan Newton, and Robert Clarke.  The art direction, costuming, and set design are equally fine at capturing the period and its excesses and cruelties.