St. Martin says he's tired of Beaumont treating him like an experiment. Beaumont nonchalantly says that St. Martin is an experiment. St.Martin loses his temper and yells that he's a human. Beaumont yells back that he's a freak. The carriage is silent and no one speaks the rest of the ride.
Beaumont publishes his book, "Experiments and Observations on the Gastric Juice, and the Physiology of Digestion", while at Plattsburgh. While he is celebrating with collegues and basking in their praise, St. Martin sneaks out in the night and leaves Beaumont forever.
Beaumont is writing a letter to St. Martin in Canada. His voice reads it while he writes. The letter talks about how Beaumont wants St. Martin to come back. He lists what he's discovered (more accurate and complete description of gastric juice, establishment that mental disturbance effects digestion, a table of digestibility of different foods and more).
Beaumont's letter even says he will pay St. Martin and they will both go down in history. St. Martin reads the letter and then writes back angrily. He says Beaumont is a greedy man and no amount of money would be enough for him to come back. He says Beaumont is only after fame and will die alone.
While St. Martin's letter is read aloud, there is a close up of Beaumont's grave. His grave reads "Beloved Son and Doctor" with his date of birth, November 21, 1785, and his date of death, April 20,1853.
St. Martin's letter is still being read as the scene changes to St. Martin laughing with his family. At the end of his letter, he says that he forgives Beaumont, but hopes they never see each other again. "I hope you enjoy your life, Beaumont, for I am surely enjoying mine." After that saying, the credits roll.