Content Warning: This section depicts recreational drug use and contains outdated and offensive language and racist stereotypes.

Narrator Dr. John Watson observes his colleague and flat-mate Sherlock Holmes as he prepares a syringe of a “seven-per-cent solution” of cocaine and injects himself. Watson objects to the physical and mental effects of the drug; however, Holmes finds the “artificial stimulants” necessary due to his current lack of work. He states that his mind “rebels at stagnation” and he “abhor[s] the dull routine of existence” (2-3). He needs a constant flow of work, puzzles, and intricate analysis, which is why he created his own profession as the “only unofficial consulting detective” (3).

Briefly, Holmes shares with Watson his correspondence with a Frenchman who considers Holmes his mentor in investigative work and speaks of his recent studies in various “minutiae” such as the differences in ash between different kinds of cigar, cigarettes, and pipe tobacco, and his study of the impressions left by footprints. Watson then asks Holmes to demonstrate his prowess in examining evidence and deductive reasoning by giving him a watch and asking him to determine who owns it.

Quickly, Holmes determines that the watch belonged to Watson’s older brother, who had financial and drinking problems before his death.