"My dear sir, do you not realize that I could knock you down or shoot you dead for what you have done, and be perfectly justified in doing so?" "If you either knock or shoot," replied the other, "you will have to do it very quickly, for, in the language of the wild and woolly West, I've got the drop on you. In my coat pocket is a cocked revolver with my forefinger on the trigger. If you make a hostile move I can let daylight through you so quickly that you won't know what has struck you." "Electric light, I think you mean," answered the doctor, quietly. "Even a Chicago man might find it difficult to let daylight through a person at this time in the evening. Now, this sort of thing may be Chicago manners, but I assure you it will not go down here in Cincinnati. You have rendered yourself liable to the law if I cared to make a point of it, but I do not. Come back with me to my study. I would like to talk with you." Stratton began to feel vaguely that he had made a fool of himself. His scheme had utterly failed. The doctor was a great deal cooler and more collected than he was. Nevertheless, he had a deep distrust of the gentleman, and he kept his revolver handy for fear the other would make a dash to escape him. They walked back without saying a word to each other until they came to the doctor's office. Into the house they entered, and the doctor bolted the door behind them. Stratton suspected that very likely he was walking into a trap, but he thought he would be equal to any emergency that might arise. The doctor walked into the study, and again locked the door of that. Pulling down the blinds, he turned up the gas to its full force and sat down by a table, motioning the newspaper man to a seat on the other side. "Now," he said calmly to Stratton, "the reason I did not resent your unwarrantable insult is this: You are conscientiously trying to get at the root of this mystery. So am I. Your reason is that you wish to score a victory for your paper. My motive is entirely different, but our object is exactly the same. Now, by some strange combination of circumstances you have come to the conclusion that I committed the crime. Am I right?" "You are perfectly correct, doctor," replied Stratton. "Very well, then. Now, I assure you that I am entirely innocent. Of course, I appreciate the fact that this assurance will not in the slightest degree affect your opinion, but I am interested in knowing why you came to your conclusion, and perhaps by putting our heads together, even if I dislike you and you hate me, we may see some light on this matter that has hitherto been hidden. I presume you have no objection at all to co-operate with me?" "None in the least," was the reply. "Very well, then. Now, don't mind my feelings at all, but tell me exactly why you have suspected me of being a murderer." "Well," answered Stratton, "in the first place we must look for a motive. It seems to me that you have a motive for the crime."