When the taxi leaves the bus station, the Logan City Taxi sign is in large white letters and close to the rear of the driver's side door. When it pulls up to the motel, the sign is much smaller and centered on the door. When the driver pulls to a halt, the sign is back in its original position and size.
While a barn correctly reads "Waters Dairy Farm," the roadside sign is mislabeled "Water's Dairy Farm" (with an inappropriate apostrophe).
When Marv picks up the duck, there's a cap on the bottle. In the next shot, the cap instantly disappears.
When Della and Paul drive up to the home where Mrs. Adams is hiding, in the long shot as the car approaches the house, the driver has black hair and clearly isn't Paul. In the next shot as the car arrives, Paul is in the driver's seat.
Trivia: We get a rare glimpse of Gertie, Perry Mason's receptionist, when Fran Celane storms into Perry's office to see him.
Trivia: This episode features one of the few instances where Perry Mason solves the murder without entering a courtroom.
Trivia: Della Street's phone number is Hollywood 2-1799.
After Perry and Paul discover the body, Mason says "That's not the same man that came to see me at the office." But Dawson met Perry at his apartment not his office.
We see the inside of Perry's law library.
We see more of Perry's apartment when Robert Dawson comes to meet him at home and when Della gives Perry medicine for his cold.
Trivia: We see more of Perry's apartment when Perry and Della are preparing for a party on the kitchen counter which opens towards the living room.
This is the only episode where we see Della give Perry a kiss... on the cheek.
Perry solves the case while testifying on the witness stand
We don't see Sheila step down from the stand after her second testimony. We do see two spectators sitting next to each other behind Burger while the judge tells Burger to examine her testimony for perjury and the next witness, the sheriff, being called to the stand. We next see Sheila when Perry looks at her while the sheriff is testifying. She is seen behind Burger sitting between the two spectators who were previously sitting next to each other. So how did she get there without being seen on camera?
We learn that Perry Mason's office phone number is MA5-1190 (Madison) when Doris Stephanak tells the operator what number to call.
Perry Mason's office telephone number is Madison 51190.
After the fire trucks arrive we see Perry talking with the neighbors, followed immediately by a close-up of him watching the fire and then segues back to him talking with the neighbors as Paul returns.
Paul Picerni's character states that he's suffering from tuberculosis yet he smokes like a chimney throughout the entire episode.
Paul Picerni's character is an escapee from a correctional institution who doesn't want his true identity to be discovered. So what's he doing sitting in the courtroom during the trial?
Dr. Maitland, supposedly a renown psychiatrist, says that Helen Reed is schizophrenic, when she is actually suffering from multiple personality disorder (now known as dissociative identity disorder).