Geoff Stevenson who's featured in this episode as Mr. Singer the patient, had been a regular background doctor prior to this episode. He'll later get the name of Seymour Beardfacé and become an even more frequent background character with a number of speaking roles through the series.
In the DVD extras, the Dick Van Dyke character is fonted "Dr. Townsend". But in the episode in which Van Dyke appears, and is removed from medical rotation, the name "Dr. Townshend" is wiped from the assignment board.