Chapter IThe Science of DeductionSherlock Holmes took his bottle from the corner of the mantel-piece andhis hypodermic syringe from its neat morocco case. With his long, white, nervous fingers he adjusted the delicate needle, and rolled backhis left shirt-cuff. For some little time his eyes rested thoughtfullyupon the sinewy forearm and wrist all dotted and scarred withinnumerable puncture-marks. Finally he thrust the sharp point home, pressed down the tiny piston, and sank back into the velvet-linedarm-chair with a long sigh of satisfaction.Three times a day for many months I had witnessed this performance, butcustom had not reconciled my mind to it. On the contrary, from day today I had become more irritable at the sight, and my conscience swellednightly within me at the thought that I had lacked the courage toprotest. Again and again I had registered a vow that I should delivermy soul upon the subject, but there was that in the cool, nonchalantair of my companion which made him the last man with whom one wouldcare to take anything approaching to a liberty. His great powers, hismasterly manner, and the experience which I had had of his manyextraordinary qualities, all made me diffident and backward in crossinghim.Yet upon that afternoon, whether it was the Beaune which I had takenwith my lunch, or the additional exasperation produced by the extremedeliberation of his manner, I suddenly felt that I could hold out nolonger."Which is it to-day?" I asked, --"morphine or cocaine?"He raised his eyes languidly from the old black-letter volume which hehad opened. "It is cocaine," he said, --"a seven-per-cent. solution.Would you care to try it?""No, indeed," I answered, brusquely. "My constitution has not got overthe Afghan campaign yet. I cannot afford to throw any extra strainupon it."He smiled at my vehemence. "Perhaps you are right, Watson," he said."I suppose that its influence is physically a bad one. I find it, however, so transcendently stimulating and clarifying to the mind thatits secondary action is a matter of small moment.""But consider!" I said, earnestly. "Count the cost! Your brain may, as you say, be roused and excited, but it is a pathological and morbidprocess, which involves increased tissue-change and may at last leave apermanent weakness. You know, too, what a black reaction comes uponyou. Surely the game is hardly worth the candle. Why should you, fora mere passing pleasure, risk the loss of those great powers with whichyou have been endowed? Remember that I speak not only as one comrade toanother, but as a medical man to one for whose constitution he is tosome extent answerable."He did not seem offended. On the contrary, he put his finger-tipstogether and leaned his elbows on the arms of his chair, like one whohas a relish for conversation."My mind," he said, "rebels at stagnation. Give me problems, give mework, give me the most abstruse cryptogram or the most intricateanalysis, and I am in my own proper atmosphere. I can dispense thenwith artificial stimulants. But I abhor the dull routine of existence.I crave for mental exaltation. That is why I have chosen my ownparticular profession, --or rather created it, for I am the only one inthe world."