Watson begins The Adventure of the Veiled Lodger not with a client at the door but with a shelf. He has yearbooks, dispatch-cases and seventeen years of notes on his friend's cases, and he states the difficulty plainly: "The problem has always been not to find but to choose." Then he tells us how he chose this one, and his reason is an odd one for a detective story.
That sentence lowers our expectations of Holmes before he has even appeared. Watson is warning us that the curious gifts of instinct and observation he usually sets out to show may not be on show here. This story is to be weighed in suffering, not in cleverness.
The visitor in Holmes's smoke-laden room is not even the woman with the trouble. It is her landlady, Mrs. Merrilow, who has seen her lodger's face once in seven years. Doyle lets the horror of that face arrive through a milkman, who caught a glimpse of it at an upper window and "dropped his tin and the milk all over the front garden." The detail is almost comic, and it does more work than a description of the wound would. We learn what the face does to people before we learn what happened to it.