Jack Klugman refused to appear in this episode because he disliked the script, so the episode was written around him. It was his first step in pushing producer Glen A. Larson and his company (including writer Michael Kozoll, later co-creator of Hill Street Blues (1981)) out the door and repeatedly holding out on new seasons until he got a production team to his liking (even then he frequently rewrote the scripts).
A total of 148 episodes were made. Jack Klugman appeared in 147. In the episode Has Anybody Here Seen Quincy? (1977) (season 2, episode 7), Dr. Asten (John S. Ragin) talks to Quincy twice on the phone, but Quincy's voice is not heard and he is not seen on screen. The reason Klugman did not take part in the episode is because he disliked the script written by Michael Sloan and Glen A. Larson for the episode; a body brought into the morgue turns out to still be alive. Klugman thought it laughable that a medical examiner of Quincy's fastidiousness would fail to notice it.
Fun fact: Almost every actor who guest starred on the original 'Star Trek', also appears on 'Quincy'. In this episode, the actress is Louise Sorel. She played Rayna in the 'Star Trek' episode, "Requiem for Methuselah."