Jack Sainsbury unloosed the black satin cravat, tore off his collar, and opened his friend's shirt at the throat. But it was all of no avail. There was no movement--no sign of life. A few moments later Thomasson came back in breathless haste. "I've spoken to Sir Houston, sir," he said. "He's on his way round in a taxi." Then both men gazed on the prostrate form which Sainsbury supported, and as they did so there slowly came a faint flush into the doctor's face. He drew a long breath, gasped for a second, and his eyes relaxed as he turned his gaze upon his friend. His right arm moved, and his hand gripped Sainsbury's arm convulsively. For a few moments he looked straight into his friend's face inquiringly, gazing intently, first as though he realised nothing, and then in slow recognition. "Why, it's Jack!" he gasped, recognising his friend. "You--I--I felt a sudden pain--so strange, and in an instant I--ah! I--I wonder--save me--I--I--ah! how far off you are! No--no! don't leave me--don't. I-- I've been shot--shot!--I know I have--ah! what pain--what agony! I--" And, drawing a long breath, he next second fell back into Sainsbury's arms like a stone. Ten minutes later a spruce, young-looking, clean-shaven man entered briskly with Thomasson, who introduced him as Sir Houston Bird. In a moment he was full of concern regarding his friend Jerrold, and, kneeling beside the couch whereon Sainsbury and Thomasson had placed him, quickly made an examination. "Gone! I'm afraid," he said at last, in a low voice full of emotion, as he critically examined the eyes. Jack Sainsbury then repeated his friend's strange words, whereupon the great pathologist--the expert whose evidence was sought by the Home Office in all mysteries of crime--exclaimed-- "The whole affair is certainly a mystery. Poor Jerrold is dead, without a doubt. But how did he die?" Thomasson explained in detail Mr Trustram's departure, and how, a quarter of an hour later, Sainsbury had arrived. "The doctor had never before, to my knowledge, locked this door," he went on. "I heard him cheerily wishing Mr Trustram good-night as he came down the stairs, and I heard him say that he was not to fail to call to-morrow night at nine, as they would then carry the inquiry further." "What inquiry?" asked Sir Houston quickly. "Ah! sir--that, of course, I don't know," was the servant's response. "My master seemed in the highest of spirits. I just caught sight of him at the head of the stairs, smoking his pipe as usual after his day's work." The great pathologist knit his brows and cast down his head thoughtfully. He was a man of great influence, the head of his profession--for, being the expert of the Home Office, his work, clever, ingenious, and yet cool and incisive, was to lay the accusing finger upon the criminal.