Answer:
Mr. Medbourne had invested in a risky business which led to his loss, resulting in his health deteriorating.
Step-by-step explanation:
Nathaniel Hawthorne's "Dr. Heidegger's Experiment" revolves around the mythological "fountain of youth" that can bring back the years from a person's past. The tale follows four friends of the scientist and their experience being young again and their greed at trying to regain the lost years, despite the warnings from their scientist friend.
Mr. Medbourne is one of the four friends that were invited by Dr. Heidegger to be a part of his experiment with the water from "the Fountain of Youth". And like the narrator stated, Mr. Medbourne "had been a prosperous merchant, but had lost his all by a frantic speculation, and was now little better than a mendicant." His decision to invest in a risky business led to the detriment in his health.