But he had not been influenced solely by that consideration. The original germ of his idea lay far back, in that projected poetic trilogy, "Genèse," which was to have recounted the advent, development, and destiny of mankind. That vague scheme, suggested by the pages of Lucretius, had been resuscitated, transformed, modernised, so to say, by the repeated perusal of Balzac's "Comédie Humaine"; and there is little doubt that, from the practical standpoint of personal advantage, Zola was also influenced by the success of many connected series of books. It is a question whether Balzac's novels were widely read at that moment. Cheap, badly printed on the vilest paper, they were to be seen in almost every bookseller's shop, but their covers, soiled and fading, often spoke of long continuance in the dealers' custody, whereas there could be no doubt of the ready sale, the immense vogue, of Erckmann-Chatrian's numerous productions. Those so-called "Romans Nationaux" hung well together, thanks to a variety of connecting links, and in their prodigious circulation Zola constantly had before his eyes an example of the great success which might attend a series of novels leading skilfully one from the other. But he did not propose to write about the past, even the near past, such as the First Republic and the First Empire, which had supplied Erckmann-Chatrian with their themes; his aim was to describe contemporary manners, those of the then-existing Second Empire. That _régime_ had begun in blood, and had passed through some remarkable phases, which would provide him with suitable backgrounds for several stories. And it followed--purely and simply as a matter of course--that the series he contemplated must be largely a record of social and natural degeneration. The degeneracy of the times was a stock subject, a commonplace of contemporary literature. The playwrights--Ponsard, Augier, Feuillet, Barrière, Sardou, Dumas _fils_, and others, had harped upon it for years. It had figured in numerous novels; it had formed the subject of many volumes of so-called "serious" literature; it had appeared in the pages of Tocqueville, it had found an echo amid even the hopefulness of Prévost-Paradol's "France Nouvelle"; it was a theme repeatedly selected by those newspapers which did not pander to the supporters of the _demi-monde_. No doubt, there has never been a time, since men began to write, when some of them have not pictured the world and the human species as degenerate. The cry, _O! tempora, O! mores_, has re-echoed through all the centuries indiscriminately. But under a _régime_ so base and corrupt as the Second French Empire it was justifiable. There could then be no doubt that degeneracy was indeed attacking the nation.