Stories / His Last Bow · 1910
The Adventure of the Devil's Foot
Two brothers mad and a sister dead around an untouched card table; Holmes tests the lamp-burned powder on himself and Watson — and nearly joins the victims.
✅ Public domain — read, share, and adapt freely.
⚠️ Spoilers below. The analysis discusses the solution, including who did it and how it's found out.
Summary & analysis
Holmes, ordered to rest in Cornwall, cannot escape a horror: a brother and two sisters found around their card table, the sisters' brother raving, one sister dead, all with faces of extreme terror and no intruder, no wound, no poison the doctors can name.
A second death — the family's other brother, an African explorer — and a residue of powder on a lamp shade give Holmes his theory. He tests it with reckless courage: burning the powder in a closed room on himself and Watson, and nearly dying to prove the mechanism.
The 'devil's-foot root', a West African toxin, was burned in the lamp to drive its inhalers mad or dead; the explorer brother killed the family for their treatment of a woman, and was in turn killed by her avenger. Holmes hears the confession and, judging the law inadequate, lets the avenger go.
Deeper reading
Horror in Cornwall
The Devil\'s Foot, set during a Cornish rest-cure, is among the canon\'s most frightening stories — two people driven mad and one killed around an untouched card table, by a poison burned into the air. Doyle wrings genuine gothic terror from the invisible agent, and the desolate coast supplies a fittingly bleak stage.
The experiment that nearly kills them
The story\'s centrepiece is Holmes testing the powder on himself and Watson, and the two barely escaping the hallucinatory horror they induce — a reckless self-experiment that dramatises the detective\'s obsessive need to know. Holmes then judges the avenging killer and lets him go, another quiet assumption of the law\'s authority.
Techniques on display
Elimination
Striking out the impossible until the truth remains.
In this story: No wound, no ingestion, no intruder: Holmes eliminates every ordinary vector until only an airborne agent remains, then hunts the residue that an inhaled poison would leave.
Observation
Reading occupation, history, and character from visible detail.
In this story: The powder on the lamp's shield and the scorch pattern point to something burned to be breathed — a clue read from soot, then confirmed at nearly fatal cost.
Practise what this story preaches: every technique above links to a tool or game built on the same method. The best way to learn the canon is to reason along with it.