She was on the show from 1950 until 1975.

One of the original panelists

All of the syndicated episodes of the show were taped months in advance, to be aired on unknown future dates in each TV market. When watching such shows, the viewer has to pay close attention to the conversations to help determine a rough idea of when the show was actually taped.

@@LaptopLarry330 And the conversations don't give you a rough idea of the date of videotaping, even if you pay close attention to this episode. In October 1971, Hugh Downs retired from NBC's Today Show, and Wally Bruner mentions that fact, but you don't know much more than that. [new paragraph] On November 24, 1971, a Wednesday during business hours, (the day before Thanksgiving), five What's My Line episodes were videotaped in New York. The panelists for all of them were Soupy Sales, Melba Tolliver, Jack Cassidy and Arlene Francis. Wally Bruner was the moderator of all five episodes. [new paragraph] How do I know all of the above? During the late 1990s, the era when Pearson Television owned the Mark Goodson archive, an employee told me that one of the November 24, 1971 episodes included a contestant who made a living disguised as Ronald McDonald. The employee said further that it seemed to be missing from the archive, but another of the five episodes, with mystery guest Monty Hall, was available. In the 1990s, I was interested only in Ronald McDonald, so I told the Pearson employee I was not going to purchase anything. During the KZfaq era, the Monty Hall episode surfaced, and you can watch it. The participants are exactly the same as the Ronald McDonald episode -- Soupy Sales, Melba Tolliver, Jack Cassidy, Arlene Francis, Wally Bruner. Here is a link. kzfaq.info/get/bejne/mdqhds6W2rHOkXU.html [new paragraph] Did anyone ever ask an archivist in charge of the Mark Goodson vault for the date when the Hugh Downs episode was videotaped? I didn't. Possibly someone else did. Someone could have asked the Mark Goodson Productions archivist in 1994, the Pearson archivist in 1999, etcetera.

Why?

I'd like to know why too