“I have been talking by telephone to-day with a Philadelphia physician and chemist, an intimate personal friend, whom I know to be an expert in the use of all kinds of drugs, and thoroughly informed as to the peculiar qualities and effects of scopolamine. If there is any man who can determine positively whether it figures in this case, that man is Doctor Grost. I have described Madame Clayton’s condition to him and he is inclined to my opinion. He has consented to come to New York and see her, and he will be here to-morrow morning. I will call here with him, Clayton, at precisely ten o’clock.” “By Jove, I am glad to know this,” Clayton earnestly declared. “It gives me a ray of hope, at least.” “You must be careful not to betray it, nevertheless,” Nick again cautioned him. “Conduct yourself precisely as if we had not discussed this matter, and as if my visit with Doctor Grost was not anticipated.” “I will do so, Carter, take my word for it,” Clayton again assured him. “I will be constantly on my guard.” “Very good,” Nick replied, rising to go. “That is all I can say to you this evening. Expect me at ten o’clock to-morrow morning in company with the Philadelphia physician. We can bank positively on one fact, Clayton, that he will speedily determine whether or not I am right.” Clayton arose, looking vastly relieved, and accompanied the detective to the door. CHAPTER IV. THE RESULT OF A RUSE. It was eight o’clock when Nick Carter left the Clayton residence. He departed without so much as a backward glance, as if he had no further interest in the house and its surroundings. He walked briskly out to his touring car, in which Danny Maloney had been waiting, and was driven rapidly away. One would have supposed that his visit was all aboveboard, that he was actuated with no covert designs, that he entertained no secret suspicions, aside from those he had expressed during his interview with Mr. Chester Clayton. Earlier that evening, nevertheless, while discussing the case with his junior partner, Patsy Garvan, it was very obvious that Nick Carter had from the first been working under the surface. Their interview occurred immediately after dinner, while Nick was making ready for his call upon Clayton. “Nothing is more effective, Patsy, than a shot from behind a masked battery,” he remarked, while knotting his cravat. “When fired at a concealed adversary, even, whose position and designs are only suspected, it is almost sure to drive him from cover.” “There is something in that, chief, for fair,” Patsy agreed. “But why do you feel so sure you are right in suspecting Clayton’s private secretary?” “For several reasons,” said Nick. “First, Patsy, because we can find no one else to distrust. I have spent three days in a vain search for another suspect and a reasonable motive for this murder.” “That’s true, chief. It sure has been a vain hunt.”