In an apparent unsuccessful murder attempt, one character shoots at another, firing six shots from a five-chambered revolver without reloading. Later, Perry comments that only five shots were fired.
The mail boxes in the magazine office are mixed up rather than being arranged in any logical order.
It's highly unlikely that any one medical examiner, no matter what the size of the city, would know of dozens of cyanide poisonings. By the middle of the twentieth century, cyanide was a controlled substance and was not being used in dozens of murders in one city.
Richard Crane, who plays Mr. George Moore, is clearly not comfortable with the glasses he's wearing in this portrayal. Someone who's worn glasses for any time at all doesn't fiddle with them as much as the Moore character does. Especially in the first half of story, he nervously touches the frames without taking them off.