He had allotted to himself a superhuman task--that of saving and rehabilitating his brother. He had sworn to him at their last interview that he would dedicate his life to the work of penetrating the frightful mystery, of discovering the real murderer, and of dragging the truth into the broad light of day. Thus he had definitively placed the working of his sand and gravel pits in the hands of a reliable manager, knowing that if he should lack money he would from the outset find his efforts crippled. Personally, he devoted himself entirely to his search for the truth, ever following up the slightest clues, ever deep in the quest for new facts. If it had been possible for his zeal to weaken, the letters from Cayenne, which his sister-in-law at long intervals received from his brother, would have sufficed to inflame his courage. Simon's departure, his embarkation with other unhappy beings, the awful voyage, the arrival yonder amid all the horrors of the penal settlement--those were scorching memories which threw David into indescribable agitation, which returned amid dreadful shudders at each and every hour. And now came letters, doctored and amputated by the officials, yet allowing one to detect beneath each phrase the cry of one who was enduring intolerable torture, the revolt of an innocent man for ever brooding over his pretended crime, and at a loss to understand why it was that he should expiate another's deed. Was not madness at the end of that devouring anguish? Simon alluded gently to the thieves and assassins, his companions; and one could divine that his hatred was directed against the keepers, the torturers, who, uncontrolled, far removed from the civilised world, became like the wild men of primeval caverns, gloating over the sufferings they inflicted upon other men. It was a sphere of mire and blood; and one evening a pardoned convict recounted such horrible particulars to David, in Marc's presence, that the two friends, their bleeding hearts wrung by terror and compassion, were stirred to furious protest and cried their pain aloud. Unfortunately the ceaseless inquiries, which both David and Marc prosecuted with discreet stubbornness, yielded no great result. They had resolved to keep a watch on the Brothers' school at Maillebois, and particularly on Brother Gorgias, whom they still suspected. But a month after the trial all three of the assistant Brothers, Isidore, Lazarus, and Gorgias, disappeared together, being sent to some other community at the other end of France. Brother Fulgence, the director, alone remained at Maillebois, where three new Ignorantines joined him. David and Marc could draw no positive conclusions from this incident, for the Brothers often went from one establishment to another. Besides, as all three assistants had been removed, it was impossible to tell to which one of them that removal was really due.