The Black Doctor

Sir Arthur Doyle was a Scottish physician and writer who is most noted for his fictional stories about the detective Sherlock Holmes, which are generally considered milestones in the field of crime fiction. He is also known for writing the fictional adventures of a second character he invented, Professor Challenger, and for popularising the mystery of the Mary Celeste. He was a prolific writer whose other works include fantasy and science fiction stories, plays, romances, poetry, non-fiction, and historical novels. 
This story «The Black Doctor» presents a puzzle of mistaken diagnosis (heart attack or murder) in the context of a mistaken identity. Doyle suggests a slippage between difference and identity, but the story eventually realigns itself under traditional, conservative mores.