"Things happen like that," said Superintendent Hanslet. "There are times at the Yard when things are as dull as ditchwater. For weeks on end we may spend our days, and our nights, too, for that matter, over the most trivial matters. And then suddenly, as happened the other day, two really important cases are thrust upon us at once."
It was ten o'clock on the evening of Saturday, August 22nd. The Superintendent had been invited to dine with his friend Dr. Priestley, that uncompromising scientist, who combined an interest in criminology with an unsparing devotion to pure mathematics, at the latter's house in Westbourne Terrace. Dinner being over, the party had adjourned to Dr. Priestley's study. There were present Dr. Priestley himself, his secretary, Harold Merefield, his friend, Dr. Oldland, a general practitioner with an extensive practice in Kensington, and the Superintendent.
