But not until two pairs of strong arms had flung him away did Dunbar forsake the door. And not until two strong pairs of shoulders had pressed themselves against the partition did the lock show signs of yielding. It was just when it began to crack that Dunbar made his dash toward the front entrance--to be thwarted by the lucky chance that Knapp blocked his way, giving Frye time to lay hands upon him, while O'Madden finished the little business of breaking down the door. As the barrier gave way, an unpleasant odor, a little like ether, penetrated to the men's nostrils. "Jumping crickets!" cried O'Madden. "What in tarnation is this!" Stretched full-length on the floor in the electric light, with pale bloodless face and inert, apparently unbreathing form, was a dishevelled young woman, her unbared left arm displaying a long bloody streak. * * * * * In the first amazed instant of the discovery, Officer Frye almost lost his grip on Dunbar. "The saints preserve us! Is she dead?" he gasped. "Looks like it," concluded O'Madden. "First let's attend to this devil, then we'll investigate." Out rattled a pair of handcuffs, which clapped themselves about Dunbar's wrists. Bending down to the girl, Frye felt her forehead. "Why, she's still warm," he discovered. "Couldn't be dead very long." "You blinking idiots!" raged the captive, struggling in O'Madden's bear-like grip. "What makes you think she's dead? Why, she'll recover soon enough. If you'll give me a chance, I'll bring her back right now. We were just performing a little experiment--" "Experiment! Like hell!" It was only then that Frye observed the hypodermic needle on the floor a few feet from the unconscious girl. "Guess you can tell them all about that down at the station house," he observed, caustically. "Meanwhile we'd better bring the lady down to the doc's office on the first floor. You just keep your grip on that thug, O'Madden!" Six-foot giant that he was, Frye had gathered the girl into his arms as easily as if she had been a sofa pillow. "By God, if you don't let me go," threatened Dunbar, his black eyes glittering like a crowd of devils dancing, "I swear you'll rue the day!" Frye's answer was a hoarse burst of laughter. But cutting through his laughter with the sharpness of an earthquake, there came a rattling and banging at the laboratory window. And while the two officers and Knapp stood as if transfixed, the window shade flew up and the window burst open, though there was nothing visible to account for the commotion, O'Madden afterwards asserted that a cold breeze blew by him, though the thermometer stood around 100; and Frye, whose courage no one had ever doubted, did not deny that the hair on his head prickled and a chill swept down his spine.