Anachronism Stew: This episode is set in approximately 1877, yet the first appendectomy wasn't performed until nearly a decade later, in 1885.
Creepy Crows: Or in this case, a singular crow... that can talk. It's ominous to hear it talk, but the crow is completely harmless.
Foreshadowing: Although one of O'Hara's "miracle cures" offers Mr. Hanson much-needed relief from his unbearable headaches, Dr. Baker points out that the underlying cause hasn't been found or treated; early in season 5, Hanson suffers a debilitating stroke that ultimately takes his life.
O'Hara's attraction includes a primate beast which an illustration in his wagon antecipates as a Killer Gorilla, only to be revealed as a harmless-looking chimpanzee. In real life, chimpanzees are more dangerous than gorillas.
Mrs. Oleson nearly dies from appendicitis after refusing treatment when she believes O'Hara's miracle powder cured her. Comes Season 6, and she will be responsible for bringing in another phony healer, a minister who claims to perform miracles, and one man whose son was suffering appendicitis will believe the same thing, with tragic consequences.
Karma Houdini: Despite being called out on his cons and forced ro expose the truth about his miracles to Laura and Mary, O'Hara faces no other consequences for almost causing Mrs. Oleson's death and continues to go on pulling his schemes, with the implication that there might be other victims of his fake cure in the future, maliciously or not.
Snake Oil Salesman: O'Hara's advertising of his miracle powder raises red flags when it captures the charm of the town to where everyone believes it works. It got to the point where its pitch almost cost Harriet her life.
Special Guest: Red Buttons as Willie O'Hara, the titular "circus man".
Throw the Dog a Bone: Depicted throughout most of the first season as haughty, dark and rude, this is truly the first episode to treat Mrs. Oleson as a sympathetic character, one where the viewers hope that, despite her faults, she will pull through her life-threatening illness.
