When the police car's siren comes on so Lt. Tragg can pull Perry over, the police car is seen in the curb lane, one lane to the right of Perry's car. The next shot, from the rearview mirror of Perry's car, shows the police car in the same lane as Perry's.
At the pool hall Perry calls his office from a pay phone, and the last two numbers he dials were 11. Earlier he put an ad in the newspaper to buy a similar trailer to the one that was stolen. His ad requested to contact him at MA-51190.
At the start, Perry and Della are talking in Perry's office and Perry is wearing a necktie which has leaping deer on it. Later, during the perjury hearing while Burger is questioning Perry, it can been seen that Burger is wearing the same necktie with the leaping deer on it.
When Perry and Della are sitting at a restaurant booth, Perry has his left arm on the top of the booth behind Della as he begins to ask the waitress (Amy) for the menu. As the view changes and Perry completes saying "Amy", his arm is on the table.
When Perry drives into the driveway of George Ballard's house, the trees are blowing in the wind. Cut to closeup of Perry getting out of car and walking to front door, and the trees are not moving.
Before his death George Ballard says several times the serial number on the bill that led him to a successful bet on a horse was '00581.' All US currency back then were silver certificates and had six-digit serial numbers with a single letter at each end. Perhaps he meant the number *ended* in 00581 but he never expressly says this.
According to George Ballard, the Mercantile Bank robbery occurred ten months before the events in this 1958 episode. Bill Emory said it was on Tuesday, May 3rd. But May 3, 1957 was a Friday. The closest previous Tuesday May 3rd was in 1955, nearly three years before the episode aired.
The color of the unmarked police car trailing Perry Mason's car does NOT change color from dark to light repeatedly. The dark unmarked car, containing LT. Tragg, is always in frame but on two occasions appears in a different lane than the car occupied by Perry Mason and Arlene Dowling as either Mason's or Tragg's car changes lanes.
As Perry and Arlene are driving, neither Perry's car nor the police car have a dashboard or rearview mirror. However, this is simply a common filming technique that is used to provide a clearer view of the car's occupants.
The currency shown in this episode is obvious stage money.
The detectives staking out Mr. Ballard's house never record the model and license number of the car parked in the driveway. This is a most implausible lapse, especially considering that a suspected criminal drives away in it.
While on the witness stand and testifying under oath, Perry names the murderer, a person who answers to the description of someone seen leaving the crime scene. Perry was speaking prematurely, as there was another strong suspect who answered to that description and had no alibi for the time the murder was committed.