"I am trying to remember a Hawaii Five 0 episode. It was about a toxin in a vial which was left in a shallow stream. Jack Lord and company were trying to find it. Regularly, as time ran out, the camera would cut to a shot of the vial in the water.
"It is not 'Three Dead Cows at Makapuu' or 'Nine Dragons,' both of which have a toxin theme. I am almost sure it was a Five-0 episode but it was the late sixties or early seventies. If you know I would appreciate it."
All I could think of was "Deadly Persuasion" (Season 8). If anyone has any idea which episode John is trying to find, please let me know. Mahalo!