What is the theme in Cousin Bette: Part One of Poor Relations by Honore de Balzac?

Jealousy is at the heart of Lisbeth Fischer's struggle to bring low her cousin Adeline Hulot and her entire family. Bette begins the story as unrefined and eccentric in a rather coarse and unbecoming way. Adeline is beautiful and kind; she marries a successful man and lives in fine style in Paris. Bette's jealousy of Adeline's seeming overabundance of good fortune is what motivates her actions and drives her internal monologue. Even when Baron Hulot's affairs with various young women continue to severely erode the family's financial status, Bette proves that jealousy can eat a person alive if it is nurtured and cultivated over a number of years.