If you don't want to know the circumstances surrounding Saturday's entry in this slideshow, then don't read any further...
[spoiler]Saturday's quote:
Ep #513 (1968) - Prof. Stokes - 'In the meantime, we MUSTN'T let this little setback defeat us. We MUST think of a new plan to destroy the witch.'
From "Robservations 6/10/02 - Liz and Stokes vs. Cassangelique - #513/514"
Tony discusses with Stokes the events that transpired in the basement of the Old House; they also talk over their strategy for destroying Cassandra (Angelique), which Tony believes impossible.
Another Robservations with very little detail. However, the quote comes up just before Tony says he beginning the believe that that's impossible. But Stokes follows up by reassuring him that being an old hand at this, it is possible, if not easy...