In Part 2, Chapter 5, Lee uses a simile to capture a quality of Hank and Jean Louise's relationship:
"This is insane, Jean Louise," he said, pulling out money, keys, billfold, cigarettes. He stepped out of his loafers.
They eyed one another like game roosters. Henry got the jump on her, but when she was falling she snatched at his shirt and took him with her. They swam swiftly in silence to the middle of the river, turned, and swam slowly to the landing.
Jean Louise and Hank's relationship has evolved significantly. He is courting her for marriage and attempting to be more gentlemanly or chivalrous with her. However, neither of them have forgotten that they were once best friends (along with Jem). At that time, Jean Louise was less feminine and more boyish (going not by Jean Louise but Scout), and their gender difference was less important.
By using this simile, Lee indicates the way in which the old relationship resurfaces in certain moments. There is a playful banter beneath more "adult" feelings and desires. Indeed, Jean Louise in part encourages Hank to go swimming because she is trying to process her complicated feelings toward him and wants to delay making a decision.
In Part 3, Chapter 8, Jean Louise finds a pamphlet on Atticus's desk called The Black Plague, which prompts a visceral reaction that Lee captures well in a simile:
She opened the pamphlet, sat down in her father's chair, and began reading. When she had finished, she took the pamphlet by one of its corners, held it like she would hold a dead rat by the tail, and walked into the kitchen. She held the pamphlet in front of her aunt.
"What is this thing?" she said.
Alexandra looked over her glasses at it. "Something of your father's."
Jean Louise stepped on the garbage can trigger and threw the pamphlet in.
As the novel progresses, Jean's disdain for her community's racism becomes more and more pronounced. Here, Lee turns around the animalizing logics of scientific racism back onto its authors by comparing the pamphlet to a dead rat. Instead of buying into its message, Jean Louise is conceptually (and even physically) disgusted by the pamphlet. It almost seems to carry the "black plague" that it attributes to another population. To try to protect herself from its contagion, Jean Louise holds it by the corner and quickly deposits it into the trash can.