Sherlock Holmes took his bottle from the corner of the mantel-piece and his hypodermic syringe from its neat morocco case. With his long, white, nervous fingers he adjusted the delicate needle, and rolled back his left shirt-cuff. For some little time his eyes rested thoughtfully upon the sinewy forearm and wrist all dotted and scarred with innumerable puncture-marks. Finally he thrust the sharp point home, pressed down the tiny piston, and sank back into the velvet-lined arm-chair with a long sigh of satisfaction.

Three times a day for many months I had witnessed this performance, but custom had not reconciled my mind to it. On the contrary, from day to day I had become more irritable at the sight, and my conscience swelled nightly within me at the thought that I had lacked the courage to protest. Again and again I had registered a vow that I should deliver my soul upon the subject, but there was that in the cool, nonchalant air of my companion which made him the last man with whom one would care to take anything approaching to a liberty. His great powers, his masterly manner, and the experience which I had had of his many extraordinary qualities, all made me diffident and backward in crossing him.

When no interesting cases are brought before Europe's premier consulting detective, Sherlock Holmes' mind rebels at stagnation and he resorts to cocaine to stimulate his thoughts. Fortunately, this does not happen a lot, as there are a great many mysteries for him to solve, the reports of which make up four novels and five collections of short stories, all written in the form of first-person recollections by his friend, assistant, and occasional room mate John Holmes, a military surgeon forced to retire early after being seriously injured in Afghanistan.

With their copyright expired, all of Conan Doyle's writings are available for free, and I am about half-way through now.