Watson goes to Smith's address. Although Smith refuses to see anyone, Watson forces his way in. Once Watson explains his errand on behalf of Sherlock Holmes, Smith's attitude changes drastically. Smith agrees to come to Baker Street within a half hour. Watson excuses himself, saying that he has another appointment, and returns to Baker Street before Smith's arrival.
Believing that they are alone, Smith is frank with Holmes. It soon emerges, to the hiding Watson’s horror, that Holmes has been sickened by the same illness that killed Smith’s nephew Victor. Smith then sees the little ivory box, which he had sent to Holmes by post, and which contains a sharp spring infected with the illness. Smith pockets it, removing the evidence of his crime. He then resolves to stay there and watch Holmes die.