This thrust, which I gave involuntarily--for I had no desire to hurt the poor woman's feelings--drove the color from her face. She retreated a step, and stumbled over a child that was playing on the floor. The slight accident seemed to infuriate her; she angrily pushed the child away with her foot, and turned upon me like a tigress. "What are you hunting us down for?" she cried. "Do you think I have not had trouble enough in my life? Driven here and there, with a pack of hungry children in rags, and tied to a man who expects me to keep a home and a family upon ten shillings a week! But he's my husband for all that, and I'm not going to help you bring a deeper disgrace upon us. You came here yesterday to set a trap for him, with a lying story that you owed him a few pence which you were anxious to pay. God knows what you wormed out of him, for, clever as he is, he's a fool when he pours the drink down his throat. I've warned him over and over again to be careful what he says; but I might as well have talked to a stone. He's out of your reach now, at all events, and you'll have a job to find him. I wish you joy of your task, you cowardly sneak!" The passion of her defiance of me was wonderful to witness; but underlying this defiance was a terror which did not escape my observation. "I came here," I said gently, for her despair and her poverty inspired me with genuine pity, "in the hope that he would assist me in the discovery of a crime which has not been brought to light. If he is not implicated in it he would have earned a few pounds; if in any way he is involved in it, all I can say is, Heaven pity him--and you!" My time was too precious to waste further words upon her, and I left the shop, and entered the cab which was waiting for me. Before I could close the door a man accosted me. "I heard what passed inside the shop," he said. "Make it worth my while, and I'll tell you something about Dr. Cooper." "Jump in," I answered; "I have no time to stop talking here." I gave the driver Ronald Elsdale's address, and we sped thitherward. "Now, what have you to say?" "You want to know where the doctor is?" he commenced. "I do." "Well, I can't tell you that exactly, but I can put you on his track. It's worth, I should say,"--he deliberated, and looked at me covertly to decide what he would be likely to screw out of me--"not less than half a crown." "I will give you that if you keep nothing back." "All right. Where's the coin?" "No, my friend," I said, "I'll have the goods before I pay for them."