The Adventures of Sherlock Holmes - The Adventure of the Engineer's Thumb

"The Adventure of the Engineer's Thumb" is one of 56 Sherlock Holmes short stories by Arthur Conan Doyle. In this story, Dr. Watson stumbles across a peculiar case, described to him by a patient who had his thumb severed by a cleaver the night before. Watson brings the story to the attention of Holmes, who agrees to get to the bottom of it.