Arriving at my house my sister took an early opportunity to urge upon Gwen a glass of wine, in which I had placed a generous sedative.  The terrible tension soon began to relax, and in less than half an hour she was sleeping quietly.  I dreaded the moment when she should awake and the memory of all that had happened should descend like an avalanche upon her.  I told my sister that this would be a critical moment, cautioning her to stay by Gwen and to give her, immediately upon her arising, a draught I had prepared for the purpose of somewhat deadening her sensibilities.  I arose early, and went to Maitland’s laboratory to collect the things he desired.  When I returned Gwen was awake, and to my intense gratification in even a better condition than I had dared to hope.

It was quite late when we reached her house, and Maitland had evidently been at work several hours.  He looked sharply at Gwen when she entered, and seemed much pleased at her condition.  “You have obeyed my instructions, I see, and slept,” he said, as he gave her his hand.  “Yes,” she replied, “I was very tired, and the doctor’s cordial quite overcame me;” and she cast an inquiring glance at the network of white string which Maitland had stretched across the carpet, dividing it into squares like an immense checker-board.  In reply to her questioning look, he said:  “French detectives are the most thorough in the world, and I am about to make use of their method of instituting an exhaustive search.  Each one of the squares formed by these intersecting strings is numbered, and represents one square foot of carpet, the numbers running from one to two hundred and eighty-eight.  Every inch of every one of these squares I shall examine under a microscope, and anything found which can be of any possible interest will be carefully preserved, and its exact location accurately marked upon this chart I have prepared, which, as you will see, has the same number of squares as the room, the area of each square being reduced from one square foot to one square inch.  You will note that I have already marked the location of all doors, windows, and furniture.  The weapon, if there be one, may be very minute, but if it be on the floor we may be assured the microscope will find it.  The walls of the room, especially any shelving projections, and the furniture, I shall examine with equal thoroughness, though I have now some additional reasons for believing the weapon is not here.”

“Have you discovered anything new?” Gwen exclaimed, unable to control the excitement caused by this last remark.  “You must pardon me,” Maitland rejoined, “if I ask you and the Doctor a question before replying.”  She nodded assent, and he continued:  “I wish to know if you agree with me that we shall be more likely to arrive at a solution of the problem before us if we keep our own counsel than if we take the officers of the law, or, for that matter, anyone else, into our confidence.  You undoubtedly noticed how carefully