"Spock's Brain" is probably the most MST3K worthy episode in TOS. So nit-picking it is gratuitous. However, I ran across a passage in THE STARFLIGHT HANDBOOK (Eugene Mallove & Gregory Matloff, John Wiley & Sons, Inc. 1989) that seemed relevant. During the opening tease, Scotty is gushing over an ion-propelled ship. "They could teach us a thing or two!" Meanwhile the Enterprise flashes between the stars at multiples of the speed of light. I guess "ion" sounded technical to the writer. Later in the episode, Scotty again remarks on "ion power"— Ooh! Do it again! In a similar vein, in the BUCK ROGERS episode "Buck's Duel to the Death," our hero must confront a gangster called the Traybor who uses electricity as a secret weapon—casting bolts like Zeus. Apparently, no one in the 25th century uses olde fashioned electricity anymore, so it's up to Buck to deal with this problem... Again, we have a writer who is unfamiliar with any physics. Electrical charge is one of the most fundamental aspects of all matter. So even if New Chicago is powered by an antimatter plant, electricity (and ions!) still comes into the picture somewhere.