At one part in this episode, Brain hits Pinky with a pencil.
Peter Hastings wrote this cartoon, and in a 1999 conversation
he told me that he never had Brain hit Pinky, in any episode.
He said he thought it was much funnier to have Brain get to
the brink of hitting Pinky, but then stop, say something funny,
and walk away. Some examples of this do exist in a few episodes.
Because of what Hastings said, it seems plausible to suspect that
the original script did not have Brain hit Pinky with the pencil.