How we cite our quotes: (Chapter. Paragraph)
Quote #1
"Really, Watson, you excel yourself," said Holmes, pushing back his chair and lighting a cigarette. "I am bound to say that in all the accounts which you have been so good as to give of my own small achievements you have habitually underrated your own abilities. It may be that you are not yourself luminous, but you are a conductor of light. Some people without possessing genius have a remarkable power of stimulating it. I confess, my dear fellow, that I am very much in your debt."
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. (1.13-4)
Poor Watson. He's happy for even that grudging respect from Holmes. He's happy when his friend gives him any kind of compliment at all—even a backhanded one. This scene immediately sets up the dynamic between Watson (the faithful and admiring writer who "[gives] publicity" to Holmes' cases) and Holmes (the rude genius who enjoys Watson's attention).
Quote #2
"Glad to meet you, sir. I have heard your name mentioned in connection with that of your friend. You interest me very much, Mr. Holmes. I had hardly expected so dolichocephalic a skull or such well-marked supra-orbital development. Would you have any objection to my running my finger along your parietal fissure? A cast of your skull, sir, until the original is available, would be an ornament to any anthropological museum. It is not my intention to be fulsome, but I confess that I covet your skull."
Sherlock Holmes waved our strange visitor into a chair. "You are an enthusiast in your line of thought, I perceive, sir, as I am in mine," said he. "I observe from your forefinger that you make your own cigarettes. Have no hesitation in lighting one." (1.56-7)
Dr. Mortimer is interested in the "science" of phrenology (which was popular in Victorian times but which was pretty much debunked). Phrenologists thought you could tell a lot about a person's character by looking at the bulges and bumps on their skulls, since skull shape would indicate which parts of their brains were most developed. The author is making a point that these two recognize each other as men of science. And as a man of science, he's worthy of Holmes' respect.
Quote #3
"It was all very confused. Sir Charles had evidently stood there for five or ten minutes."
"How do you know that?"
"Because the ash had twice dropped from his cigar."
"Excellent! This is a colleague, Watson, after our own heart. But the marks?"
"He had left his own marks all over that small patch of gravel. I could discern no others." (3.43-7)
This bit of sleuthing by Dr. Mortimer's really catches Holmes' attention. Watson probably wishes he could get that kind of unqualified admiration from Holmes. Once again, it's the scientific deductions that get respect. Watson's lifetime of loyalty and affection—well, that's just not as exciting.