The operator of an establishment (such as a saloon or bar) would charge customers to see an attraction (such as an animal) and then serve a “complimentary” alcoholic beverage, thus circumventing the law. “In desperate cases it has to betake itself to the exhibition of Greenland pigs and other curious animals, charging 25 cents for a sight of the pig and throwing in a gin cocktail gratuitously.”
The difference between a speakeasy and a blind pig was that a speakeasy was usually a higher-class establishment that offered food, music, or entertainment, or even all three. In large cities, some speakeasies even required a coat and tie for men, and evening dress for women. But a blind pig was usually a low-class dive where only beer and liquor were offered.