It was on the 4th of March. I rose earlier than usual. I rang the bell and gave our landlady a signal that I was ready. Then I picked up a magazine from the table. One of the articles had a pencil mark, and I began to read it.

      Its ambitious title was “The Book of Life,” and it attempted to show how much an observant man might learn by an accurate and systematic examination of everything. For me, it was a remarkable mixture of shrewdness and of absurdity. The writer claimed by a momentary expression, a twitch of a muscle or a glance of an eye, to fathom a man’s inmost thoughts.

      Observation and analysis! That’s all.

      “From a drop of water,” said the writer, “a logician[10] can infer the possibility of an Atlantic or a Niagara. All life is a great chain. Like all other arts, the Science of Deduction and Analysis requires long and patient study to attain the highest possible perfection in it. By a man’s finger nails, by his coat-sleeve, by his boot, by his trouser knees, by the callosities of his forefinger and thumb, by his expression, by his shirt cuffs-by each of these things a man’s life is plainly revealed.”

      “What ineffable twaddle!” I cried and slapped the magazine down on the table, “I never read such rubbish in my life.”

      “What is it?” asked Sherlock Holmes.

      “This article,” I said. “It irritates me. It is not practical. Let’s bring that author to a carriage on the underground, and ask to give the trades of all the travellers. I will lay a thousand to one against him.”

      “And you will lose your money,” Sherlock Holmes remarked calmly. “As for the article[11] I wrote it myself.”

      “You!”

      “Yes. The theories which are chimerical to you, are really extremely practical-so practical that I depend upon them for my bread and cheese[12].”

      “And how?” I asked involuntarily.

      “Well, I’m a consulting detective, if you can understand what that is. Here in London we have lots of Government detectives and lots of private ones. When these fellows don’t know what to do, they come to me, and I help them. You saw Mr. Lestrade, he is a well-known detective. But sometimes even he doesn’t know what to do.”

      “And these other people?”

      “They are people who are in trouble about something. I listen to their story, they listen to my comments, and then I earn some money.”

      “But do you mean to say,” I said, “that you here can unravel some knot which other men can’t?”

      “Quite so. I have intuition. You see I have a lot of special knowledge which I apply to the problem, and which facilitates matters wonderfully. The rules of deduction in that article which aroused your scorn, are invaluable to me in practical work. You were surprised when I told you about Afghanistan.”

      “Someone told you about it, no doubt.”

      “Nothing of the sort. I knew you came from Afghanistan. What did I think? Here is a gentleman of a medical type, but with the air of a military man. Clearly an army doctor, then. He came from the tropics, for his face is dark, and that is not the natural tint of his skin, for his wrists are fair. He underwent hardship and sickness, as his haggard face says clearly. His left arm is injured. Where did an English army doctor meet all this? Clearly in Afghanistan. I then remarked that you came from Afghanistan, and you were astonished.”

      “It is simple enough as you explain it,” I said. “You remind me of Edgar Allen Poe’s Dupin[13].”

      Sherlock Holmes rose and lit his pipe.

      “You think that you are complimenting me,” he observed. “Now, in my opinion, Dupin was a very inferior fellow. He had some analytical genius, no doubt; but he was not a phenomenon as

      Poe imagined.”

      “And what about Gaboriau’s works[14]?” I asked. “What do you think of Lecoq? Is he a real detective?”

      Sherlock Holmes sniffed sardonically.

      “Lecoq was a miserable bungler,” he said, in an angry voice; “The question was how to identify an unknown prisoner. I can do it in twenty-four hours. Lecoq took six months or so. These books can teach the detectives what to avoid.”

      I walked over to the window, and looked out into the busy street.

      “This fellow may be very clever,” I said to myself, “but he is certainly very conceited.”

      “There are no crimes and no criminals in these days,” he said, querulously. “No use to have brains in our profession. I can make my name famous.”

      I was annoyed at his bumptious style of conversation. I decided to change the topic.

      “I wonder what that fellow is looking for?” I asked. A man was walking slowly down the other side of the street. He had a large blue envelope in his hand.

      “You mean the retired sergeant of Marines[15],” said Sherlock Holmes.

      “Oh!” thought I to myself. “He knows that I cannot verify his guess.”

      Suddenly the man saw the number on our door, and ran rapidly across the roadway. We heard a loud knock, a deep voice below, and heavy steps.

      “For Mr. Sherlock Holmes,” he said. He stepped into the room and handed my friend the letter.

      Here was an opportunity to check my companion’s words.

      “May I ask you,” I said, “what your trade may be?”

      “Commissionaire, sir,” he said, gruffly.

      “And you were?” I asked, with a malicious glance at my companion.

      “A sergeant, sir, Royal Marine Light Infantry[16], sir.”

      Chapter III

      The Lauriston Garden Mystery

      This was the fresh proof of the practical nature of my companion’s theories. My respect for his powers of analysis increased wondrously. When I looked at him he was reading the note.

      “How did you deduce that?” I asked.

      “Deduce what?” said he, petulantly.

      “That he was a retired sergeant of Marines.”

      “I have no time for trifles,” he answered, brusquely; then with a smile, “Excuse my rudeness. So you actually were not able to see that that