Virtue, my pet, is an abstract idea, varying in its manifestations with the surroundings. Virtue in Provence, in Constantinople, in London, and in Paris bears very different fruit, but is none the less virtue.
La vertu, mignonne, est un principe dont les manifestations diffèrent selon les milieux : la vertu de Provence, celle de Constantinople, celle de Londres et celle de Paris ont des effets parfaitement dissemblables sans cesser d’être la vertu.
Original text (French)
Notes from Wikiquote
Part I, ch. XVIII