“When a doctor does go wrong he is the first of criminals.”

“I said that he was my superior in observation and deduction. If the art of the detective began and ended in reasoning from an armchair, my brother would be the greatest criminal agent that ever lived. But he has no ambition and no energy. He will not even go out of his way to verify his own solutions, and would rather be considered wrong than take the trouble to prove himself right.”

“The London criminal is certainly a dull fellow. Look out of this window, Watson. See how the figures loom up, are dimly seen, and then blend once more into the cloudbank. The thief or the murderer could roam London on such a day as the tiger does the jungle, unseen until he pounces, and then evident only to his victim. There have been numerous petty thefts. This great and sombre stage is set for something more worthy than that. It is fortunate for this community that I am not a criminal.”

“When a man does a queer thing, or two queer things, there may be a meaning to it, but when everything he does is queer, then you begin to wonder”

“I think that I had better go, Holmes.""Not a bit, doctor. Stay where you are. I am lost without my Boswell.”

“It is fortunate for this community that I am not a criminal.”

“So swift, silent and furtive were his movements like those of a trained bloodhound picking out a scent, that I could not but think what a terrible criminal he would have made had he turned his energy and sagacity against the law instead of exerting them in its defense.”