The Adventures of Sherlock HolmesChapter 10
Speckled Band Viper Thwarted
Helen Stoner fears stepfather Dr. Roylott repeating sister Julia's mysterious death via whistle and 'speckled band.' At Stoke Moran, Holmes deduces a swamp adder trained to enter via ventilator and bell-rope.
Outcome
Snake recoils fatally on Roylott during vigil; Helen saved, inheriting safely.