Continuity mistake: Mary gets out of her car at the gas station wearing white shoes, but when she is being shown her room at the boarding house by Mrs Thomas she is wearing black shoes. This also happens at other times during the film, where Mary's shoes change from white to black and vice-versa.
Continuity mistake: During the scene in Dr Samuels' office, when Mary says "I don't see what this has to do with it" he has both hands on the desk, but when he replies "the point is this" he only has his right hand on the desk. On the next shot when asks Mary "do you agree?" he has both hands back on the desk.