According to the story, one Saturday Jem and Scout are out exploring and hunting for squirrels with their air rifles. Scout notices that Jem is looking at something and when she asks him what he has seen he replies that he has seen a dog. The name of the dog is “old Tim Johnson” which both Jem and Scout know.

“Whatcha looking at?”

“That old dog down yonder,” he said.

“That’s old Tim Johnson, ain’t it?”

“Yeah.”

The dog’s owner is Mr. Harry Johnson who lived in the southern edge of the town and was a bus driver. The dog was liver-colored. After seeing the dog they both ran back home to tell Calpurnia that the dog was not well and was behaving strangely. Finally Calpurnia sees the dog and notices it has developed rabies. She calls Atticus who kills the dog with a single shot much to the shock of his children.

I love the section where Atticus takes out the old dog, it is amazing to see the way that Scout thinks so little of him at the beginning of the chapter.  He doesn't "drive a dump truck," he isn't "the sherriff," he just works in an office and goes about his business.  He isn't tough or dangerous or really much of anything that Scout could brag about.

Then old Tim Johnson (yeah that was the name of the dog) gets rabies and decides to put Atticus' children in danger.  Atticus raises a rifle and puts a round through the dog's head from quite a distance and without any hesitation.

Suddenly Scout learns that her father is a "dead shot" and perhaps he isn't quite such a weenie after all.