Dr. Heidegger welcomes his guests into his study and asks for help in an "experiment."
He demonstrates the effect of the water in the vase on an old withered rose. He then reminds his guests of the myth of the fountain of youth, and explains that his friend has sent him this elixir from its waters.
The Doctor explains that he doesn't want to grow young again, but that he'll observe his guests if they drink.
Heidegger sits back and watches as his guests drink the water, become young again (or at least believe that they become young again), and romp about his apartment.
He asks them to calm down after they shatter the vase full of water.
Heidegger picks up his rose as it withers back to its original state. He declares that he loves it as much this way as when it was young and beautiful.
The Doctor explains that he has learned a lesson from his experiment; he wouldn't drink from the fountain for anything.