In "Dr. Heidegger's Experiment," how does the doctor convince his old friends to participate in his experiment?
Dr. Heidegger has called together four of his old acquaintances, three men and one woman, all of whom are elderly, too, and of questionable reputation through misfortune and mistake. They were
...a little beside themselves,--as is not unfrequently (sic) the case with old people, when worried either by present troubles or woeful recollections.
Because these friends of the doctor are neither satisfied with the past, or content with the present, Heidegger believes they will be receptive to his experiment. In order to prove how his latest experiment works, he draws from an ancient book a dried rose of fifty years and places it in water sent to him from a friend in Florida where he discovered the Fountain of Youth near Lake Macaco. When Heidegger places the rose in this water placed in a vase, the rose is restored to its bloom with drops of dew upon its petals.
After seeing this miracle, the friends willingly quaff the bubbling liquor in their champagne glasses. Within minutes they feel the rush of youthful vigor fill them, imbuing them with urges long forgotten. And, because they were once competitors for the attentions of Widow Wicherly, the men again vie for her favors, even fighting one another while the solemn Dr. Heidegger sits and observes them. To his disappointment, under the "rejuvenescent power" of the liquid, the friends forget all that age and experience have taught them. Thus, the experiment demonstrates that people of the character of his friends--mendacious, cruel, and superficial--are incorrigible, and given another opportunity would yet pursue their prurient and illusory pleasures.