As he spoke, he turned to the window and started for it. It was not the sound of his approaching footsteps that warned the listener, however. Nick had already stiffened and drawn back as soon as his ears caught the difference in Follansbee’s tones, caused by the fact that the latter had faced about toward the window while in the act of making his last remark. The thin, stunted shadow of the head physician of St. Swithin’s was already on the shade, and quick work was necessary on Nick’s part. CHAPTER XXI. IN NEED OF EVIDENCE. Nick Carter moved with the quickness of a cat. In a twinkling he had jerked the ear piece away and slipped it into his pocket. While doing so, he had straightened up noiselessly and started along the platform of the fire escape in the direction of his own window. It was a close shave. Follansbee had started to raise the shade before Nick even reached the railing over which he had to climb, and while he was crawling over the barrier the sash of Stone’s window was being lifted. Fortunately for him, however, Follansbee tried to make as little noise as possible, consequently his movements were slower than they otherwise would have been. For all that, though, the detective was not out of sight by the time Follansbee stuck his head and shoulders through the opening. It was a tense moment, and Nick’s heart skipped a beat or two. Should Follansbee happen to glance that way the first thing and catch a glimpse of his feet disappearing through the window the consequences would be disastrous. Despite the temptation to do so, he did not forget his caution for a moment, or allow his extreme haste to betray him into a clumsy move. He slipped from view almost noiselessly, and tiptoed away from his window into the shadows of his room. All the time he was listening intently for some evidence that Follansbee had seen him, but none came. Seemingly the physician continued to climb through Stone’s window, and, having done so, proceeded on his stealthy way down the fire escape. The detective heard a slight sound, followed by the grating of the sash. Evidently the ex-miner had again closed the window. As soon as Nick dared, he ventured back and stealthily peered over his own sill. Follansbee was then descending the painter’s ladder. And when the bottom was reached, he lifted the ladder carefully away from the lower platform of the fire escape and carried it, with considerable difficulty, back to the place from which it had been taken. Subsequently his figure vanished, going in the direction of the open end of the court. “The end of the first act,” thought Nick, “and the play promises to be a hair-raiser.”