There you have the whole truth of it. You can hang me, or do what you like with me, but you cannot punish me as I have been punished already. I cannot shut my eyes but I see those two faces staring at me — staring at me as they stared when my boat broke through the haze. I killed them quick, but they are killing me slow; and if I have another night of it I shall be either mad or dead before morning. You won’t put me alone into a cell, sir? For pity’s sake don’t, and may you be treated in your day of agony as you treat me now.

“What is the meaning of it, Watson?” said Holmes solemnly as he laid down the paper. “What object is served by this circle of misery and violence and fear? It must tend to some end, or else our universe is ruled by chance, which is unthinkable. But what end? There is the great standing perennial problem to which human reason is as far from an answer as ever.”

In the third week of November, in the year 1895, a dense yellow fog settled down upon London. From the Monday to the Thursday I doubt whether it was ever possible from our windows in Baker Street to see the loom of the opposite houses. The first day Holmes had spent in cross-indexing his huge book of references. The second and third had been patiently occupied upon a subject which he had recently made his hobby — the music of the Middle Ages. But when, for the fourth time, after pushing back our chairs from breakfast we saw the greasy, heavy brown swirl still drifting past us and condensing in oily drops upon the windowpanes, my comrade’s impatient and active nature could endure this drab existence no longer. He paced restlessly about our sitting-room in a fever of suppressed energy, biting his nails, tapping the furniture, and chafing against inaction.

“Nothing of interest in the paper, Watson?” he said.

I was aware that by anything of interest, Holmes meant anything of criminal interest. There was the news of a revolution, of a possible war, and of an impending change of government; but these did not come within the horizon of my companion. I could see nothing recorded in the shape of crime which was not commonplace and futile. Holmes groaned and resumed his restless meanderings.

“The London criminal is certainly a dull fellow,” said he in the querulous voice of the sportsman whose game has failed him. “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,” said I, “been numerous petty thefts.”

Holmes snorted his contempt.

“This great and sombre stage is set for something more worthy than that,” said he. “It is fortunate for this community that I am not a criminal.”

“It is, indeed!” said I heartily.

“Suppose that I were Brooks or Woodhouse, or any of the fifty men who have good reason for taking my life, how long could I survive against my own pursuit? A summons, a bogus appointment, and all would be over. It is well they don’t have days of fog in the Latin countries — the countries of assassination. By Jove! here comes something at last to break our dead monotony.”