The Setup: Mr. Burns is suffering from a disease that requires a blood transfusion, and Bart has the same rare blood type.
A Work in Progress: Two Homerisms debut in this episode: Homer's back-and-forth conversations with his brain, and his use of a mocking, high-pitched voice.
The massive stone head of Olmec Indian Xtapolapocetl appears for the first time. It can occasionally be seen in the background of shots that take place in the Simpson's basement.
This episode premiered on July 11th, 1991, an attempt by Fox to extend the established 30 week TV season. Although it aired after "Three Men and a Comic Book", the official season two finale, this episode is included in the second season DVD set.
Homer: Don't you know the story of Hercules and the lion?
Bart: Is it a Bible story?
Homer: Yeah, probably. Anyway, once upon a time, there was a big mean lion who got a thorn in his paw. All the village people tried to pull it out, but nobody was strong enough! So, they got Hercules. And Hercules used his mighty strength, and Bingo! Anyway, the moral is, the lion was so happy, he gave Hercules this big... thing... of riches.
Bart: How did a lion get rich?
Homer: It was the olden days!
Marge: Homer, you don't do things like that to be rewarded. You do them because a fellow human being needs a helping hand.
Homer: Marge, you're my wife, I love you very much, but you're living in a world of make-believe! With flowers and bells and leprechauns and magic frogs with funny little hats.
Bart: Yeah, Mom, we got hosed.
Homer: Hello, my name is Mr. Burns. I believe you have a letter for me.
Postal Clerk: Okay, Mr. Burns, uh, what's your first name?
Homer: ... I don't know.
Teebore's Take: As the second season draws to a close, it's clear that Mr. Burns is already the favored supporting cast member, having been featured heavily in four episodes throughout the season. Though his run of episodes in the fifth season remain my favorites, this is still a fun and memorable Mr. Burns ep, with great characterization for Homer and Bart (in particular, Homer's cooling off after writing an insulting letter to Mr. Burns, which Bart then mails because he knows Homer would inevitably cool off) and some good moments for Marge and Lisa (this is the episode in which Lisa is using flashcards to teach Maggie that nature doesn't stop at the barnyard so she'll have all the advantages Lisa never had).
The ending, in which the family debates the moral of the story (Bart insisting the head is a great reward while Homer points out they wouldn't have gotten anything if he hadn't written the insulting letter in the first place) is classic "Simpsons": taking on an established sitcom trope (the moral of the story) and giving it their own satirical, tongue-in-cheek spin, ultimately determining that while the story had no moral (it was "just a bunch of stuff that happened!"), it "certainly was a memorable few days."
A great outing for Mr. Burns, the debut of several Homerisms, and Homer's attempts to outsmart the postal service make this a definite classic, one of those episode people often talk about when talking about "The Simpsons."