The adventure of the blue carbuncle 1892: Sherlock Holmes in

Watson visits his friend Holmes at Christmas time and finds him contemplating a battered old hat, brought to him by the commissionaire Peterson after the hat and a Christmas goose had been dropped by a man in a scuffle with some street ruffians. Peterson takes the goose home to eat, but later returns to Holmes with a blue carbuncle his wife had found in the bird's crop (throat). Holmes makes some interesting deductions concerning the owner of the hat from simple observations of its conditio...