To Kill A Mockingbird Summary of Chapter 10
Atticus sets some rules with Jem about the use of his new gun. He doesn't wanting him shooting at birds, but he is sure that Jem will. He explicitly tells him never to shoot a mockingbird, since they are the most innocent of the birds.
That afternoon a mad dog wanders down the street. Calpurnia rushes the children inside and calls Atticus to tell him. Atticus arrives with the town sheriff, Heck Tate. Heck aims for the dog, but realizes that he might miss. He tells Atticus that he should take the shot, to the surprise of the children. Atticus kills the dog instantly. The event greatly affects Jem and he warns Scout not to mention this at school. Scout is confused but Jem tells her that if Atticus wanted them to know what a good shot he was, he would have told them.