You will notice that he starts and stops on queue with every sentence. If they just gave the horse something sticky he would have continued to move his lips after the synced words. So what made him stop perfectly with the words? There is no way they created his speech with the amount of time he moved his lips.
I suppose you are talking about the column How did they get Mr. Ed to talk? The use of a string was covered there in an update.
I recently was reading an excerpt from Alan Young’s autobiography online. According to his autobiography, he always used to tell people that they used peanut butter to make Mr. Ed talk because no one on the show wanted to reveal how they did it. But they always used a string, never peanut butter. And Bamboo Harvester got so good at it that he’d start “talking” whenever Alan would stop talking.
Love watching Mr. Ed! It’s now on Antenna TV and I watch it often. Just love that horse! I’m amazed how he could pick up all those things in his mouth, like the phone.
Lassie’s Timmy, Jon Provost, was on Mr. Ed, and he states most emphatically that it was monofilament fishing line, not peanut butter, that moved Mr. Ed’s lips.