The doctor signs his name "Dr. T.V. Reynolds" in a telegram, but it is printed as "Dr. J.C. Reynolds" in a newspaper.
When McBride and Gahagan enter O'Brien's apartment, the light coming in through the window is off a beat or two before the lights come on inside when McBride throws the switch. A similar goof occurs during the fight in the lab. The oil lamp on the table is knocked over and goes out, but there is a delay in the light in the room going out - and then another delay before the light coming in through the window comes on.