In "To Kill a Mockingbird" what disaster happens at Christmas between Scout and Francis?

In Chapter 9 of "To Kill a Mockingbird," the Finch family gets together with Atticus's brother Jack for Christmas dinner.  Scout's cousin Francis tells her that his grandmother is going to teach him to cook; Scout scoffs at this statement, saying that "boys don't cook."  Then, when Scout mentions that she does not want Dill to wait on her after they are married, Francis ridicules Dill, calling him a "runt."  They argue, and Francis tells Scout,

You're mighty dumb sometimes, Jean Louise.  Guess you don't know any better, though.

When Scout asks him what he means, Francis replies,

If Uncle Atticus lets you run around with stray dogs, that's his own business, like Grandma says, so it ain't your fault.  I guess it ain't your fault if Uncle Atticus is a nigger-lover besides, but I'm here to tell you it certainly does mortify the rest of the family--

Francis goes on to say that Grandma says that Atticus is letting the family down.  Rising and sprinting far enough away, he yells, "He's nothin' but a nigger-lover!"  To this Scout runs and "collars" him, but Francis yells the insult again, running into the kitchen.  So, Scout waits for the opportunity for him to come back out, but Francis calls to his grandmother that Scout is keeping him from coming out.  With confidence after Scout is scolded, Francis emerges and go outside.  Softly he hurls the invective again.  But, this time Scout punches him in the teeth, skinning her hand. Uncle Jack pins her arms while Grandma wipes away Francis's tears while Scout gets a spanking from Uncle Jack.

This chapter marks a difficult time for Scout as she has had to answer to insults about her father both at school and in her home environment. And, she is beginning to learn how easily people are influenced by others when they do not think for themselves.