Having learned all the facts bearing upon the case known by my visitors, I informed them of my terms for conducting an investigation of this character, and sketched a hasty outline of my plan of operation. As they had already hinted their suspicions to a member of the city detective force, who was inclined to make light of them, I suggested that they inform him that they had changed their minds in the matter, having learned from the Cleveland physicians that death was surely caused by congestion of the lungs. They then took their departure, saying that they would lay my plan before Mr. Richard S. Trafton, and he would telegraph to me whether I should proceed with the operation. On Christmas day, I received a telegram from Mr. Trafton, briefly instructing me to proceed, and my plan was put in operation at once. Before proceeding further with the history of my connection with this case, it will be necessary to remind the reader of the anomalous condition of social and business affairs in Chicago at the time of which I write; for, without any explanation, he might have difficulty in understanding many things in connection with the story. It will be remembered that the Great Fire of Chicago occurred October 8 and 9, 1871, and this case was placed in my hands only about nine weeks afterward. At the time of Mr. Trafton's death, a pall of smoke hung over the city, and, at night, the still-smouldering heaps of coal throughout the "burned district" glowed like volcanic fissures, casting a weird fantastic light about the ruins, and illumining the clouds of smoke overhead with a ruddy glow which was visible for miles away. The streets were filled with dust and ashes, while the fumes of carbonic acid gas were sometimes almost stifling. To venture, at any time, into the waste of ruins, which stretched more than three miles in one direction, through the formerly richest portion of the city, was not a pleasant undertaking; but to make such an excursion at night was attended with more hazard than most peaceably-disposed men would care to run. There were no gaslights, no sidewalks, no street indicators; in many places, piles of stone and brick were heaped in almost impassable barricades from one side of the street to the other; all landmarks were gone, and the old resident was as liable to lose his way as the stranger.