In a strange, roundabout way, it is getting bitten by a dog that makes Catherine Earnshaw more concerned with acting like a lady.
In their typical mischievous fashion, Catherine and Heathcliff have been peeking through the windows of Thrushcross Grange to poke fun at the Linton children, Edgar and Isabella. In their usual rough-and-tumble style, the two have been very unkind to the meeker children inside, making “frightful noises” and doing their best to be unpleasant.
However, their fun turns to fear when the Linton’s bulldog, Skulker, chases them and winds up biting Catherine on the ankle. With an injured ankle, Catherine is taken into Thrushcross Grange and cared for, while Heathcliff is referred to as a “gypsy” and turned away.
During the five weeks Catherine spends with the Linton family while recuperating, Catherine becomes something of a pet project for Mrs. Linton, and she is transformed from the wild young girl who used to play with Heathcliff into a polite and well-mannered young lady. She is exposed to a new way of life involving “fine clothes and flattery” and is transformed into “a very dignified person.”
Despite this change, though Catherine is reserved in the way she greets the dogs upon her return home, her eyes “[sparkle] joyfully,” implying that the old Catherine is still there under her new layers of finery.