Published in 1890, "The Sign of Four" was Doyle's second work, featuring the legendary detective Sherlock Holmes. The first chapter is appropriately titled "The Science of Deduction", and serves as a wonderful introduction to the enigmatic man and his methods. Holmes asserts that there are "three qualities necessary for the ideal detective", namely knowledge, the power of observation, and the power of deduction. Holmes' abilities at observation are superb, as evidenced by some of the books he's produced on obscure topics like the tracing of footsteps, the influence of a trade on the form of a hand, or the enumeration of 140 forms of cigar, cigarette and pipe tobacco ash. He is careful to distinguish mere observation from clear deductive reasoning, and it is the latter which really is the essence of Holmes. To him the only thing that is important is "the curious analytical reasoning from effects to causes" by which he unravels a case. Already in the opening, he demonstrates his powers of deduction by coming to stunning and perfectly logical conclusions about Watson's brother, merely by seeing his watch. What is obscure to everyone, is of course perfectly obvious to Holmes: "so absurdly simple that an explanation is superfluous." He is the epitomy of deduction and cold hard reason.
While Holmes is the embodiment of reason, Watson is the embodiment of emotion. Holmes is naturally critical of the emotional and romantic streak in Watson. "Detection is, or ought to be, an exact science and should be treated in the same cold and unemotional manner." When Watson comments on the attractiveness of Holmes' client, he replies "Is she? I did not observe." Completely deprived of emotion, he looks not at beauty, but at cold hard facts. "It is of the first importance not to allow your judgment to be biased by personal qualities ... The emotional qualities are antagonistic to clear reasoning." In this story Watson finds himself a wife, something Holmes would never consider: "...love is an emotional thing, and whatever is emotional is opposed to that true cold reason which I place above all things. I should never marry myself, lest I bias my judgment." Fortunately we need not share Holme's cold and emotionless tastes to love him, because we are involved in the story through the first person narrative of Watson, who has more than enough emotion and romance to make up for what Holmes lacks. Watson is a brilliant literary device for Doyle, because it enables us to portray Holmes with his cold logic without having to identify with him. Instead we identify with Watson as passive observers and view Holmes himself as a curious object to be marvelled at.
We need not identify with Holmes to appreciate his passion for deduction. In "The Sign of Four" Holmes applies his powers of deduction to a remarkable case involving Mary Morstan, whose father disappeared under mysterious circumstances some ten years earlier. Investigation uncovers the facts of his death, and the suprising discovery that he has bequeathed her a tremendous treasure. The plot thickens as the treasure disappears along with a classic locked-room murder mystery. Mysterious notes with "The Sign of Four" seem to be the only clue to the mystery. Of course only Holmes can and does unravel the mystery, even when all the other police detectives are desperately misled by both clues and lack of reason. As usual Holmes will cooperate with them, but only on his terms: "You are welcome to all the official credit, but you must act on the lines that I point out."
As with "A Study in Scarlet", we're again introduced to the elements that typify a Sherlock Holmes story. Holmes utilizes "the unofficial force - the Baker Street irregulars" to help him. They consist of a dozen dirty and ragged little street Arabs, whom Holmes pays in return for information gleaned from the streets. "They can go everywhere, see everything, overhear everyone." Holmes also utilizes the power of disguise, which he expertly uses to even pull the wool over the eyes of his companion Watson. But "The Sign of Four" also gives a glimpse of Holmes' weakness - an addiction to morphine and cocaine. The justification is that he only resorts to the use of drugs when he is not busy with a case. "My mind rebels at stagnatism." "Hence the cocaine. I cannot live without brainwork." He much prefers the mental challenge of a case "...it would prevent me from taking a second dose of cocaine." But just as Holme's intellectual brilliance stimulates himself, so it stimulates the reader. In the process of his deductions, he evidences an astute understanding of people, articulating gems like this: "The chief proof of man's real greatness lies in his perception of his own smallness." On carefully asking people the right questions: "The main thing with people of that sort is never to let them think that their information can be of the slightest importance to you. If you do they will instantly shut up like an oyster." On women: "Women are never to be entirely trusted - not the best of them." And as with most mysteries, as readers we are reminded of what lengths the passions of greed and revenge will go in corrupting human behaviour.
As in all the Sherlock Holmes stories, Holmes himself unquestionably emerges the hero. However, Doyle had not yet perfected the Sherlock Holmes formula, because in the lengthy extended flashback of the final chapter as the murderer describes his story Holmes himself falls to the background. The truth is, we want more of Holmes and his deduction, and that's what Doyle perfected in his later short stories. But if deduction is indeed a science as Holmes believes, then he himself is its greatest scientist, and there are few pleasures greater than seeing this enigmatic scientist at work in the laboratory of life. -GODLY GADFLY