Sherlock Holmes, a famous private detective, is sitting in his Baker Street apartment with Dr. John Watson. They are looking at a walking stick that has been left behind by an unknown visitor the night before. Holmes hopes that he can determine something about the visitor based on the scant evidence provided by the walking stick.
The stick has a small dedicatory plaque on it that reads, “To James Mortimer, M.R.C.S., from his friends of the C.C.H.” alongside a date. Holmes asks Watson to “reconstruct” the visitor they’ve missed. From the amount of wear and tear on the stick, Watson believes that Mortimer is an elderly country doctor who does most of his travelling by foot.
M.R.C.S. means “Membership of the Royal College of Surgeons.” It’s a degree that certifies Mortimer in a specific type of surgery, but not for general practice. Though he’s often referred to as “Doctor,” Mortimer is careful to mention that he’s “only” an M.R.C.S.
Watson also notes that Mortimer must be esteemed by his colleagues, because the walking stick is well-made and expensive-looking, and the plaque is made of silver. He believes that “C.C.H.” probably refers to a local hunting club (the “H” being “Hunt”) that Mortimer assisted at some point.
Watson’s deduction that the “H” in “C.C.H.” stands for hunt doesn’t make much sense—there’s no evidence to back it up. The flimsy deduction is based entirely on Watson’s belief that Mortimer is a country doctor.
Holmes congratulates Watson on his deductions, telling him that he has constantly underrated himself. Holmes says that he is very much in Watson’s debt. Watson, who narrates the encounter, remarks at the pleasure that this rare praise from Holmes causes him.
The moment is short-lived, however, as Holmes quickly points out that Watson was wrong about most of his deductions. Holmes was in Watson’s debt not because of Watson’s great skill but because, in thinking about how fallacious Watson’s thinking was, Holmes was able to properly guide his own thinking.
Holmes is unspeakably cruel to his devoted friend in this moment. It serves as one of many instances where Holmes’ hyper-rationality makes him act insensitively in situations that require empathy and care.
Watson was correct, Holmes says, that Mortimer is a practitioner who walks a great deal. However, Holmes thinks it’s far more likely that the “H” in “C.C.H.” stands for “Hospital.” If that’s true, then he believes the hospital to be Charing Cross Hospital—an urban institution. Holmes thinks that Mortimer’s coworkers gave him the walking stick when he decided to leave the hospital and start up his own practice in the country.
Holmes’ belief that “H” stands for “Hospital” is based on the fact of Mortimer’s advanced medical degree rather than conjecture (as Watson’s was). This kind of deduction is Holmes’ hallmark. It is always grounded purely in the material facts of a case with no room for imagination, which can quickly lead one astray.
Holmes goes on to suggest that Mortimer could not have been a part of the regular staff of the hospital, since it would be unlikely that someone in such a prestigious position would start up a lowly country practice. Instead, he must have been a house-surgeon or physician—a “senior student.” If that’s true, then the date on the stick, only five years prior, makes Watson’s assertion that the doctor was an old man impossible.
In the Victorian era, surgeons were seen as a lower class of medical practitioner because they actually touched the body. Physicians, who simply prescribed medicine, were considered the highest evolution of the career.
Holmes thus posits Mortimer as a “young fellow, under thirty, amiable, unambitious, absent-minded” and, he goes on to add, the owner of a dog—one larger than a terrier but smaller than a mastiff. Holmes gleans this last deduction from the chew marks found here and there on the stick. He feels that Mortimer is unambitious because he would not have left the hospital otherwise.
Though it’s early on in the book, Mortimer owning a larger dog begins to establish him as a red herring. The book, after all, is called The Hound of the Baskervilles, and this is the first mention of a hound. What’s more, the mention comes as part of a small mystery.
Watson points out how impossible it is to confirm most of Holmes’ suspicions without meeting Mortimer. The professional aspects, though, he can easily check using his medical directory. Sure enough, when Watson consults the book, he finds that Mortimer was indeed a house-surgeon at Charing Cross Hospital some years before.
Indeed, many of the features that Holmes attributes to Mortimer never come to light, as he is—despite this long meditation on him—a quite minor character. Mostly, this moment serves to display Holmes’ deductive prowess to the reader.
Holmes looks out the window and gently mocks Watson for his failure to come to the correct conclusions. Holmes goes on to explain in greater depth how he arrived so easily at them. As he’s discussing how he deduced that the dog must be between a terrier and a mastiff, Holmes exclaims decidedly that the dog is a curly-haired spaniel. Watson, in exasperation, demands to know how Holmes could possibly know the exact breed of dog. Holmes says that it’s simple: he’s just seen Mortimer and his dog walk up to the apartment.
It’s interesting that Holmes has such an impressive amount of knowledge about dog breeds. This isn’t because he’s a dog enthusiast, however. Instead, he knows that understanding the bite radius of different dogs might help him solve a case. This is part of what would today be called forensic science, a branch of criminology that was only beginning to gain traction at the time.
Mortimer is relieved to find his walking stick, saying that he wouldn’t lose it for the world. Holmes questions him to see if his earlier deductions were correct. They were mostly correct, except that Mortimer left Charing Cross Hospital because he got married, not because of a lack of ambition.
Holmes is far more concerned with knowing that he was right about Mortimer than he is about knowing the reason for Mortimer’s visit. Coupled with his earlier treatment of Watson, it’s easy to see that Holmes is arrogant about his skillful deductive reasoning.
Mortimer says that he knows Holmes and Watson by reputation. He goes on to talk at length about Holmes skull. As a phrenologist, Mortimer is convinced that Holmes’ skull must be as unique as the man himself. He even goes so far as to ask Holmes if he can feel his head and possibly even make a cast of it—until the “original is available.”
Mortimer’s discussion with Holmes is strange and off-putting. While he talks about Holmes with reverence, he also treats him as a kind of object to be studied. This clinical detachment lends to Mortimer’s early status as a red herring.
Holmes ignores this banter and asks Mortimer pointedly why he’s come. Mortimer responds that it is because, when it comes to being a detective, Holmes has the second greatest scientific mind in the world and the first when it comes to practical matters. Annoyed, Holmes asks who the greatest scientific mind in the world is, to which Mortimer responds Monsieur Bertillon. Holmes crossly suggests that Mortimer get on with his story.
The Bertillon Mortimer refers to is Alphonse Bertillon, a famous French police officer who invented a system of identifying criminals by measuring parts of their body. This system is still partly in use today. Comparing Holmes to a real-world detective makes the story more realistic, just as it is about to take a supernatural turn.