The Case of Lady Sannox
The story features an arrogant surgeon, Douglas Stone, who is in love with the married Lady Sannox, one of the most beautiful women in London. On his way to a rendezvous with her, the surgeon is asked by a Turkish man to operate on the latter's wife, who has cut her lip with a poison envenomed scimitar. The doctor is informed the woman will die if the poison is not cut out.
Because of his desire to meet his lover, his need for money, his professional arrogance, and the opinion of the Turk that any delay would kill his wife, the surgeon goes ahead with the operation on the heavily drugged wife, whose face is obscured by a veil. After he has performed the operation, Dr. Stone realizes his patient is Lady Sannox, and the Turk her husband, who believes the disfigurement will be morally good for his wife. The surgeon suffers a breakdown.
Charles Prepolec, in bakerstreetdozen.com, calls it "Doyle’s strongest horror story" and says that "Doyle’s ability to involve the reader is masterfully demonstrated in the wonderfully intriguing hook in the opening paragraph."