Jerce, even though presumably alone, did not allow all his feelings to be seen on his face. But he felt that the room was stifling in spite of its being a cold winter's evening, and opened the window to gain a breath of sharp air. As he stepped out, he was suddenly grasped from behind, and the skilful exercise of a Ju-Jitsu motion placed him prostrate at the mercy of his assailant. In the light of the drawing-room lamps streaming through the open window, Jerce could see that the man wore grey clothes. He would have spoken, or would have called for assistance, but the grey man placed his hand on what is called Adam's apple, and paralyzed by pressure the vocal chords. Jerce lay voiceless and motionless, as though in a state of catalepsy, while the man went systematically through his pockets with the dexterity of a thief. In less time than it takes to tell, the assailant had failed to find what he sought, and, rising quickly, disappeared like a shadow, or a ghost. All the time he had spoken no word, and had not allowed his face to be seen. As his retreating feet scrunched the snow, Jerce, too shaken to rise immediately, lay where he was, wondering what had taken place, and wondering, most of all, why this very dexterous thief had gone through his pockets so thoroughly. Then he rose to his feet and found that his gold watch, his not inconsiderable sum of money, his rings and his silver match-box were all safe. Evidently, the assailant was no common thief. He had desired to find something, and had failed to find it, but what that something might be, Jerce could not think. When he came quite to himself--for the shock of the assault had somewhat stunned him--he rushed along the terrace, and into the garden, which was parted by a single iron railing from the lane. But there was no one to be seen. The man in grey had vanished swiftly into the night, and Jerce could no more guess in which direction he had gone, than he could surmise why the man had assaulted him. He stared from the elevation upon which he stood, over the spectral wastes of snow, and then turned to re-enter. For the moment it was in his mind to send for the police; but he could give so scanty a description of his daring opponent, that it hardly seemed worth while. Not even the cleverest detective could recognise the man, from the mere fact that he wore grey clothes. However, just as Jerce turned the corner of the terrace to re-enter by the still open French window, he heard the click of the iron gate as it swung to. A tall figure walked briskly up the snowy path, and, seeing him at the corner of the terrace, advanced towards him with an ejaculation of astonishment. "Doctor," exclaimed the new-comer, bending forward to examine the features of the outraged man in the uncertain light. "I knew you were coming down, but I did not expect to find you out of doors on this freezing night."