“I will trouble you to step inside, sir,” he said, “queer things are happening here, your presence is required,” then added, pointing to the constable: “the other gentleman as well, perhaps; but no, he might prefer the duty of getting the ladies out of the way; it is no sight for women.” The calm, authoritative manner of the workman impressed the two officers, and the sergeant mechanically ordered his subordinate: “Make them move on, please!” Then the sergeant followed the man into the empty room with its four blank walls; the latter led the officer straight to the party-wall that had lately been reconstructed by the landlord’s orders. “What do you see there?” he demanded, pointing a finger at the white surface. The sergeant looked long and curiously at the spot indicated. “I see a stain,” he announced at last, “a brown, or is it a red stain. What does that mean?... Are you poking fun at me? might you be wishing to pull my leg, I wonder. Now, to start with, I call upon you to explain yourself, why did you refuse to open that door to the young lady when she asked you?” The workman shrugged his shoulders: “That’s not the question in hand,” he said quietly. “What do you think of that stain? I ought to tell you it made its appearance immediately after I had made a hole by driving in a nail.” “I think nothing,” retorted the sergeant, “except that all this is nonsensical and incomprehensible balderdash.... Yes, and that I am going to take you to the station for having put the authorities to unnecessary trouble!” The workman went on smiling: “_Unnecessary!_” he remarked; “do you think so?” To disabuse the sergeant of such an idea, the other picked up a hammer and started hammering the wall round the little brown patch; the plaster broke away in little flakes that crumbled and fell in dust on the floor, and presently, under the rain of blows, the wall itself showed a crack. Suddenly a brick tumbled out, and the officer, who was watching the operation with eyes of amazement, sprang back with a cry of horror, while even the paper-hanger himself gave a little start of surprise. Behind the plaster, in the inside of the wall, which was of considerable thickness, appeared an appalling sight! It was a human head, wan and livid, a man’s head with features streaked and spotted by the discolorations of death! The sergeant gazed at the workman in indescribable agitation. “What is it?” he asked, “what is it? I call upon you to tell me what it is?” “It is a dead man, no doubt of that—a dead man they’ve walled up in that wall, there can be no doubt of that either!” “But in that case,” exclaimed the sergeant, “it must be a question of crime, murder! It is a most grave and serious matter; the Commissary must be advised!” The mysterious workman bowed: “I am entirely of your opinion,” he said, “the presence of the Commissary appears to me to be indispensable.”