Not really a horror movie, but rather a mobster movie with a mad scientist component added to it. It doesn't really work, and only Karloff's performance keeps it from complete mediocrity. Lugosi is also good, but he isn't in the movie nearly as much as he ought to be.

Tough to classify thriller combines Film Noir themes with mild SF as a gangster's brain is transplanted into the body of a mild-mannered college professor. Stanley Ridges delivers a memorable performance, but Karloff steals the movie as the mad scientist who starts out with noble motives. Lugosi is played up in promotional material, but the part is exceedingly small and not at all a noteworthy addition to his credits.

They don't make 'em like this anymore... which in this case is kind of a good thing

a movie like this couldn't pass for horror anymore, but it did have some interesting ideas, and it was entertaining enough.