A Study in Scarlet · Chapter
II: The Science of Deduction explained
Watson and Holmes move into 221B Baker Street and settle into their new lodgings.
What happens
Watson and Holmes move into 221B Baker Street and settle into their new lodgings. As Watson observes Holmes's peculiar habits and vast but eccentric knowledge, Holmes reveals that he is a consulting detective and explains his methods of observation and deduction. He demonstrates his skill by deducing that Watson served in Afghanistan, and later correctly identifies a visitor as a retired sergeant of Marines.
Themes in this chapter
Rationality and Deduction
Holmes explains his method of observation and deduction, demonstrating how rational analysis can reveal a person's history and profession.
Friendship and Partnership
Watson and Holmes begin their cohabitation at 221B Baker Street, laying the foundation for their future partnership.
Characters to notice
- Dr. Watson
Narrates the chapter, moves into Baker Street, and becomes increasingly curious about Holmes's abilities.
- Sherlock Holmes
Described as a consulting detective with extraordinary powers of observation and deduction; reveals his methods and his disdain for fictional detectives like Dupin and Lecoq.
- Stamford
Mentioned as having confirmed that Holmes is not studying medicine.
- Mr. Lestrade
Mentioned as a well-known detective who consulted Holmes on a forgery case.
- Dupin
Referenced by Watson in comparison to Holmes; Holmes dismisses him as inferior.
- Lecoq
Referenced by Watson; Holmes criticizes him as a miserable bungler.
Key passages
“By a man’s finger nails, by his coat-sleeve, by his boot, by his trouser knees, by the callosities of his forefinger and thumb, by his expression, by his shirt cuffs—by each of these things a man’s calling is plainly revealed.”
A person's profession can be deduced from small details like their fingernails, clothing, and physical marks.
Holmes explains the basis of his deductive method to Watson.
“I have a trade of my own. I suppose I am the only one in the world. I’m a consulting detective, if you can understand what that is.”
Holmes describes himself as a unique professional—a consulting detective who helps other detectives solve cases.
Holmes reveals his profession to Watson for the first time.
“You appeared to be surprised when I told you, on our first meeting, that you had come from Afghanistan.”
Watson was astonished when Holmes correctly deduced that he had served in Afghanistan.
Holmes demonstrates his deductive reasoning by recounting how he knew Watson's background.