Factual error: Dr Lamb is about to use the electrotherapy on Newgate. As he approaches Newgate, the electrodes spark as though the switch has been flipped to engage the electricity. Lamb then puts both electrodes into one hand, but there is no reaction as there should have been with the electrodes connecting.
Revealing mistake: When Millie is being carried away, her head remains completely upright as though under her own control. If she was dead her head would hang back.
Other mistake: During the dinner scene we see Finn pour Newgate a drink. Newgate then goes to drink from it when Eliza kicks him so he spills it. However due to the width of the table this should be impossible.
Audio problem: When we see a close up of the LP playing on the gramophone, you can occasionally see the needle is not actually touching the LP but sound is still heard.
Continuity mistake: Newgate arrives at the asylum and Dr. Lamb asks someone to help remove his coat. However the scarf around his neck vanishes between shots.
Continuity mistake: When Newgate is feeding the blind woman in the asylum, the position of her hands on him when he is pretending to be her son keep changing from the chest, to his neck, to his head.
Factual error: Newgate makes a reference to Mickey Finn's name being the same as that of a Chicago bartender who used to drug his patrons with knockout drops. However, the film is set in 1899, but the real Mickey Finn wasn't caught until 1903.