“Yes,” replied Thorndyke, “there is an excellent clue, if it can only be followed up. We found a most unmistakable footprint; and what is more, we took a plaster cast of it. Would you like to see the cast?” Without waiting for a reply, he opened the research-case and took out the cast, which he placed in my hands. “Just take it round and show it to them,” he said. The superintendent had witnessed Thorndyke’s amazing proceedings with an astonishment that left him speechless. But now he sprang to his feet, and, as I walked round the table, he pressed beside me to guard the precious cast from possible injury. I laid it carefully down on the table, and as the light fell on it obliquely, it presented a most striking appearance--that of a snow-white boot-sole on which the unshapely patch, the circular heel, and the marks of wear were clearly visible. The three spectators gathered round, as near as the superintendent would let them approach, and I observed them closely, assuming that this incomprehensible move of Thorndyke’s was a device to catch one or more of them off their guard. Fred Barnett looked at the cast stolidly enough, though his face had gone several shades paler, but Mrs. Barnett stared at it with starting eye-balls and dropped jaw--the very picture of horror and dismay. As to James Barnett, whom I now saw clearly for the first time, he stood behind the woman with a singularly scared and haggard face, and his eyes riveted on the white boot-sole. And now I could see that he wore a suit of blue serge and that the front both of his coat and waistcoat were thickly covered with the shed hairs of his pets. There was something very uncanny about this group of persons gathered around that accusing footprint, all as still and rigid as statues and none uttering a sound. But something still more uncanny followed. Suddenly the deep silence of the room was shattered by the shrill notes of a clarinet, and a brassy voice burst forth: “_When the pigs their wings have folded_ _And the cows are in their nest----_” We all spun round in amazement, and at the first glance the mystery of the crime was solved. There stood Thorndyke with the red table-cover at his feet, and at his side, on the small table, a massively-constructed phonograph of the kind used in offices for dictating letters, but fitted with a convoluted metal horn in place of the rubber ear-tubes.