a professional case of great gravity was engaging my own attention at the time, and the whole of next day i was busy at the bedside of the sufferer. it was not until close upon six o’clock that i found myself free and was able to spring into a hansom and drive to baker street, half afraid that i might be too late to assist at the dénouement of the little mystery. i found sherlock holmes alone, however, half asleep, with his long, thin form curled up in the recesses of his armchair. a formidable array of bottles and test-tubes, with the pungent cleanly smell of hydrochloric acid, told me that he had spent his day in the chemical work which was so dear to him.