As one of them searched him Locke was still unconscious. They found nothing but a few bank-notes and the automatic revolver that Locke always carried.
Slowly Locke regained his senses. The agony of his strained thumbs was almost unbearable. But he was not the man to give up.
By this time two of the emissaries had gone, leaving one, who seated himself quite close to Locke, where he was examining the revolver. With the stoicism of an Indian, Locke manfully tried to evolve a plan by which he might escape. Like a flash it came to him, but it was a plan so fraught with the possibility of failure that he would not have decided on it except for the agony of the strain on his thumbs.
Directly opposite him and at a distance of four or five feet was a door leading to a back alley. This door the emissary now guarding him had locked as a precaution against surprise and had carefully placed the key in his vest pocket.
Locke weighed each detail of his plan and then, bracing his feet firmly against the wall, he suddenly shot his lower limbs forward and, like the closing of a pair of giant shears, he wrapped his legs about the neck of the emissary and immediately exerted enormous pressure with his knees.
The emissary, taken totally by surprise, struggled to break the hold, and Locke's thumbs were almost wrenched from their sockets. But he held on grimly. Soon the thug's struggles subsided, Locke released him, and he slipped to the floor.
Locke was wearing a low-cut shoe. Strange that a man's life may hinge on such a slight detail, but this fact enabled him to work off his right shoe and his sock. He extended his bare foot, and with his toes searched the pocket of the emissary for the key to the door. Finally he found it.
Locke held the key as firmly as he might between his toes and, projecting his body by a muscular effort far away from the wall, he managed to insert the key in the lock. He turned it. The door was unlocked now. A swift downward movement of his foot against the knob and the door swung open.
He braced himself against its edge and, with his back firmly pressed against the wall, relieved the strain on his thumbs. He rested a moment and then, as it were, walked up the edge of the door until his feet reached the top. Swinging one leg over the door, by patient effort he was enabled to release one swollen thumb, then the other. An instant later he dropped down and leaned exhaustedly against the wall.
While Locke was held in the room things had happened which would have set him nearly crazy with anxiety. Eva, having heard nothing from him, had become alarmed and had telephoned to the chemist. This was at quarter to five, and she had supposed that it was the chemist who answered her. In reality it had been an emissary, and he had told her that the final experiment to find an antidote for her father's malady had been really a failure and that Locke had left some time before.