About Dr. Watson

John Watson is intelligent, if lacking in Holmes's insight, and serves as a perfect foil for Holmes: the archetypal late Victorian / Edwardian gentleman against the brilliant, emotionally detached analytical machine. Furthermore, he is considered an excellent doctor and surgeon, especially by Holmes. For instance, in "The Adventure of the Dying Detective," Holmes creates a ruse that he is deathly ill to lure a suspect to his presence, which must fool Watson as well during its enactment. To that effect in addition to elaborate makeup and starving himself for a few days for the necessary appearance, Holmes firmly claims to Watson that he is highly contagious to the touch, knowing full well that the doctor would immediately deduce his true medical condition upon examination.

Watson is well aware of both the limits of his abilities and Holmes's reliance on him:

"Holmes was a man of habits... and I had become one of them... a comrade... upon whose nerve he could place some reliance... a whetstone for his mind. I stimulated him... If I irritated him by a certain methodical slowness in my mentality, that irritation served only to make his own flame-like intuitions and impressions flash up the more vividly and swiftly. Such was my humble role in our alliance." – "The Adventure of the Creeping Man"
Watson sometimes attempts to solve crimes on his own, using Holmes's methods. For example, in The Hound of the Baskervilles, Watson efficiently clears up several of the many mysteries confronting the pair, and Holmes praises him for his zeal and intelligence. However, because he is not endowed with Holmes's almost-superhuman ability to focus on the essential details of the case and Holmes's extraordinary range of recondite, specialised knowledge, Watson meets with limited success in other cases. Holmes summed up the problem that Watson confronted in one memorable rebuke from "A Scandal in Bohemia": "Quite so... you see, but you do not observe." In "The Adventure of the Solitary Cyclist," Watson's attempts to assist Holmes's investigation prove unsuccessful because of his unimaginative approach, for example, asking a London estate agent who lives in a particular country residence. (According to Holmes, what he should have done was "gone to the nearest public house" and listened to the gossip.) Watson is too guileless to be a proper detective. And yet, as Holmes acknowledges, Watson has unexpected depths about him; for example, he has a definite strain of "pawky humour", as Holmes observes in The Valley of Fear.