His literary creed at the time he began the Rougon-Macquart series may be conveniently summed up in a few words from an article which he had only a month before written in the Gaulois:  “If I kept a school of morals,” he says, “I would hasten to place in the hands of my pupils Madame Bovary or Germinie Lacerteux, persuaded that truth alone can instruct and fortify generous souls.”

In La Fortune des Rougon, then, Zola set out to plant the roots of the great family tree which was to occupy his attention during the next twenty years of his life.  His object was to describe the origin of the family which he had selected for dissection in his series, and to outline the various principal characters, members of that family.  Mr. Andrew Lang, writing on this subject in the Fortnightly Review, points out that certain Arab tribes trace their descent from a female Dog, and suggests that the Rougon-Macquart family might have claimed the same ancestry.  Adelaide Fouque came of a race of peasants who had long lived at Plassans, a name invented by Zola to conceal the identity of Aix, the town in Provence where his youth had been spent.  She was highly neurotic, with a tendency to epilepsy, but from the point of view of the naturalistic novelist she offered many advantages.  When a mere girl she married a man named Rougon, who died soon afterwards, leaving her with a son named Pierre, from whom descended the legitimate branch of the family.  Then followed a liaison with a drunken smuggler named Macquart, as a result of which two children were born, the Macquarts.  Adelaide’s original neurosis had by this time become more pronounced, and she ultimately became insane.  Pierre married and had five children, but his financial affairs had not prospered, though by underhand methods he had contrived to get possession of his mother’s property, to the exclusion of her other children.  Then came the Coup d’Etat of 1851, and Pierre, quick to seize his opportunity, rendered such services to the Bonapartist party as to lay the foundation of the family fortune, a foundation which was, however, cemented with treachery and blood.  It was with these two families, then, both descended from a common ancestress, and sometimes subsequently united by intermarriage, that the whole series of novels was to deal.  They do not form an edifying group, these Rougon-Macquarts, but Zola, who had based his whole theory of the experimental novel upon the analogy of medical research, was not on the outlook for healthy subjects; he wanted social sores to probe.  This is a fact much too often overlooked by readers of detached parts of the series, for it should always be kept in mind that the whole was written with the express purpose of laying bare all the social evils of one of the most corrupt periods in recent history, in the belief that through publicity might come regeneration.  Zola was all along a reformer as well as a novelist, and his zeal was shown in many a bitter newspaper controversy.  It has been urged against him that there were plenty of virtuous people about whom he could have written, but these critics appear to forget that he was in a sense a propagandist, and that it was not his metier to convert persons already in the odour of sanctity.