"Ah, it's you, Plantat," said the doctor in a suppressed tone; "where is Monsieur Domini?" "Gone." The doctor did not take the trouble to repress a vexed motion. "I must speak with him, though," said he, "it's absolutely necessary--and the sooner the better; for perhaps I am wrong--I may be mistaken--" M. Lecoq and M. Plantat approached him, having carefully closed the door. The doctor was paler than the corpse which lay under the sheet. His usually calm features betrayed great distress. This change could not have been caused by the task in which he had been engaged. Of course it was a painful one; but M. Gendron was one of those experienced practitioners who have felt the pulse of every human misery, and whose disgust had become torpid by the most hideous spectacles. He must have discovered something extraordinary. "I am going to ask you what you asked me a while ago," said M. Plantat. "Are you ill or suffering?" M. Gendron shook his head sorrowfully, and answered, slowly and emphatically: "I will answer you, as you did me; 'tis nothing, I am already better." Then these two, equally profound, turned away their heads, as if fearing to exchange their ideas; they doubted lest their looks should betray them. M. Lecoq advanced and spoke. "I believe I know the cause of the doctor's emotion. He has just discovered that Madame de Tremorel was killed by a single blow, and that the assassins afterward set themselves to disfiguring the body, when it was nearly cold." The doctor's eyes fastened on the detective, with a stupefied expression. "How could you divine that?" he asked. "Oh, I didn't guess it alone; I ought to share the honor of the theory which has enabled us to foresee this fact, with Monsieur Plantat." "Oh," cried the doctor, striking his forehead, "now, I recollect your advice; in my worry, I must say, I had quite forgotten it. "Well," he added, "your foresight is confirmed. Perhaps not so much time as you suppose elapsed between the first blow and the rest; but I am convinced that the countess had ceased to live nearly three hours, when the last blows were struck." M. Gendron went to the billiard-table, and slowly raised the sheet, discovering the head and part of the bust. "Let us inform ourselves, Plantat," he said. The old justice of the peace took the lamp, and passed to the other side of the table. His hand trembled so that the globe tingled. The vacillating light cast gloomy shadows upon the walls. The countess's face had been carefully bathed, the blood and mud effaced. The marks of the blows were thus more visible, but they still found upon that livid countenance, the traces of its beauty. M. Lecoq stood at the head of the table, leaning over to see more clearly.