The Lost World Season 3 Episode 18 The Elixir

Challenger takes on the problem of food shortages by inventing a nutritional elixir that would eliminate world hunger. He decides to test the concoction himself, but an unintended side effect causes him to experience vivid hallucinations. An apparition of his younger self appears in his lab, urging the older professor to shun his comrades and pursue glory at any cost.