It was the next-to-last episode [the 27th] of West’s first season and the fourth to feature Michael Dunn as Dr. [Miguelito] Loveless.Read more here.
The episode, written by John Kneubuhl (creator of Dr. Loveless) and directed by Richard Donner, removed all of the limits from the villain’s initial encounters with U.S. Secret Service agents James West (Robert Conrad) and Artemus Gordon (Ross Martin).
Loveless is determined to kill humanity to restore Earth’s ecological balance. The villain has come up with a chemical, when mixed with water, will spur men to hallucinate and go into a murderous rage.
For a while, that whole installment was available on YouTube. But as so often happens, someone complained about a copyright infraction, so the video is now down. Too bad. “The Night of the Murderous Spring” is a weird episode (as was often true of that CBS-TV series combining the spy, Western, and fantasy genres), but it’s well worth watching if you can get your hands on a DVD collection of the first season.
* * *A bit of trivia, courtesy of The Wild Wild West Web site: “The lake assigned to the evil duty of releasing the ducks that would carry Loveless’ drug across the land is actually the man-made lake used as the lagoon in Gilligan’s Island, since demolished and turned into a studio parking lot.”