Anachronism Stew: Nellie is shown eating an ice cream cone, which wasn't invented until 1896.
Bait-and-Switch: When Adam finally gets to take his law exam, he reveals that he wasn't in the top 3% needed to enter law school. When Mary says that he'll just have to take the exam again next year, he says that won't happen...as he finished in the top 1%!
In-Joke: The crate of explosives is supplied by "McCray and Co."; Kent McCray was the series producer and best friend/business partner of Michael Landon.
Innocently Insensitive: Adam is ecstatic about regaining his sight, loudly proclaiming how wonderful it is and how beautiful the world looks... right in front of his permanently blind wife. He even gushes how lucky he is that Mary is so beautiful, making her wonder if he would have stopped loving her if she wasn't, despite him assuring her he'd love her regardless.
Non Fatal Explosion: While retrieving a crate of Braille books for the Blind School, Adam loses his balance and stumbles into a crate of blasting oil; though Adam survives the subsequent explosion, he suffers a concussion that ultimately restores his vision.
Series Continuity Error: Nels claims that being fat comes from Harriet's side of the family, forgetting that he has a sister, Anabelle, whom he alienated for being ashamed of her obesity and with whom he seeked to make amends in the eponymous episode.
"Shaggy Dog" Story: Mrs. Oleson spends several days worried about her silhouette as she waits for the arrival of her far leaner cousin, even taking diets and wearing a painful tight corset. Then when her cousin arrives, it turns out that she gained a lot of weight and is much fatter than Harriet ever was.
Tap on the Head: Averted when Adam is mugged and gets a blow to the head, shortly after suffering a concussion which restored his sight. It gets him back to the hospital and he almost loses his sight again.
Temporary Blindness: What Adam's blindness turned out to be — one caused by injury, and by sheer fate, a concussion resulting from an explosion in a warehouse restores his sight.
Wham Line: "Jonathan! Jonathan! I can see! I CAN SEE!!", after Adam regains consciousness in his hospital bed, realizes he's regained his sight and begins joyfully running down the hall until he sees his friend for the first time.
