"Why," said Jen, with a nod, "if a post-mortem examination had been made, traces of poison would have been discovered. The poison would have been proved as identical with that of the devil-stick. Thus, beyond all doubt, we should have learned that Maurice had been killed by the devil-stick." "Well?" "Well!" repeated Jen, in an irritated tone, "can you not rouse that dull brain of yours to some understanding? To avert the discovery, and to prevent the analysis of the poison in the body. Dido, under the direction of Dr. Etwald, committed the third crime." "But why should Dido act so under Etwald?" "Because the man has some power over her. What that power may be, I know no more than you do. Although," added Jen, with an afterthought, "you may be able to explain." "No. I have no idea why Dido should serve Etwald." Evidently it was impossible to extract information from so impenetrable a man. Jen was thoroughly enraged by this display of obstinacy in a quarter where he least expected to find it. Usually sweet-tempered--especially toward his boys--the major quite lost control of his passion at the moment. "Take care, David," he said, in an angry manner. "You are forcing me to believe that you are acting in this way from an unworthy motive. It is your duty to aid me in discovering and punishing the murderer of Maurice. Yet you leave me to do all the work and refuse your assistance in any way. Unless you alter your manner, and take me into your confidence regarding the reason of this strange behavior, a breach not easily mended may occur between us." He paused, waiting for his ward to make some reply in defense of his conduct. The young man neither moved nor spoke, but, paler than usual, he stood before the major with his eyes on the ground. More in sorrow than in anger, Jen looked at him, then turned on his heel with a shrug, and walked into the house. David looked after him with quivering lips. "If he only knew the truth," said he, wiping the perspiration from his face, "what would he say? What would he do? He blames me now; would he blame me then?" In the meantime, while Sarby was indulging in this enigmatical soliloquy. Major Jen was pursuing his way toward the room of Jaggard. Despairing of obtaining information from David he thought it possible to learn the truth--at all events of that fatal night--from Jaggard. Honestly speaking the major was puzzled by the conduct of his ward. Hitherto, he had always considered David to be an honest man, but at the present time his conduct savored of duplicity. Did he know of anything relative to the triple crime which had been committed? If so, why did he not speak? Finally, was David also under the fatal influence of Dr. Etwald--the man who, Jen verily believed, was the source of all these woes?