The Hound of the Baskerville is the novel where we really get to know Watson well.  He steps out from behind Holmes’s shadow.  For a large portion of the book, Watson is on his own.  He believes thatHolmes is in London, and he is the legman finding clues for him.  He is proud of his role.  Yet Watson feels frustrated by never really being able to be inside the case, fully informed.

Over the course of the Holmes series, Watson goes from roommate and friend to protégé.  He is a doctor and an intelligent man in his own right, but simply cannot reach the heights of Holmes’s intellect.  As the novel opens, Holmes quizzes Watson about the walking stick and Watson has some success.

He had never said as much before, and I must admit that his words gave me keen pleasure, for I had often been piqued by his indifference to my admiration and to the attempts which I had made to give publicity to his methods. I was proud too to think that I had so far mastered his system as to apply it in a way which earned his approval. (enotes pdf p. 5)

Holmes praises him on one hand for recognizing details yet degrades his observations as “elementary” on the other hand.  Watson realizes that though he thought he had been doing well, his intellect and observational skills simply cannot compare to Holmes.

Watson is clearly trying.  He is not a trained detective, but he has spent enough time with Holmes that he thinks he has picked up some formidable skills.  Watson sends Holmes detailed reports.  He sees his solo trip to the moor as an opportunity to demonstrate to Holmes that he really does have talent, and even possibly show him up.

[If] I should find the hut and its tenant should not be within it I must remain there, however long the vigil, until he returned. Holmes had missed him in London. It would indeed be a triumph for me if I could run him to earth, where my master had failed. (p. 80)

Unfortunately, Watson is once again several steps behind Holmes.  When he realizes that Holmes has been hiding on the moor nearby all along, he is horrified and hurt.  He feels used and misled, and a little foolish.

“Then you use me, and yet do not trust me!” I cried, with some bitterness. “I think that I have deserved better at your hands, Holmes.” (p. 86)

Watson is aware that Holmes does not regard people with the same sensitivity that most human beings do, but he always expects Holmes to warm up to him and treat him as an equal.  Watson is so taken aback by Holmes’s appearance because he finally thought he was making his own mark as a detective, or at lease becoming useful and indispensable, only to discover that Holmes was making his own avenues of investigation and keeping them from Watson.

Watson grows to recognize that he will always be a dog lapping at his master’s heels. 

My friend was in excellent spirits over the success which had attended a succession of difficult and important cases, so that I was able to induce him to discuss the details of the Baskerville mystery. I had waited patiently for the opportunity, for I was aware that he would never permit cases to overlap. (p. 110)

Holmes did not bother to inform Watson of the details before, even as the case was wrapping up.  To Holmes, there was no need.  He does not recognize that he should reward Watson’s hard work and friendship by indulging his curiosity.  Yet Watson accepts his role patiently, and is content to bask in the sight of greatness.