“Yes, that is as scientific as possible. I have placed there only the members of the family, and I had to give an equal part to the partners, to the fathers and mothers come from outside, whose blood has mingled with ours, and therefore modified it. I had indeed made a mathematically exact tree, the father and the mother bequeathing themselves, by halves, to the child, from generation to generation, so that in Charles, for example, Aunt Dide’s part would have been only a twelfth—which would be absurd, since the physical resemblance is there complete. I have therefore thought it sufficient to indicate the elements come from elsewhere, taking into account marriages and the new factor which each introduced. Ah! these sciences that are yet in their infancy, in which hypothesis speaks stammeringly, and imagination rules, these are the domain of the poet as much as of the scientist. Poets go as pioneers in the advance guard, and they often discover new countries, suggesting solutions. There is there a borderland which belongs to them, between the conquered, the definitive truth, and the unknown, whence the truth of to-morrow will be torn. What an immense fresco there is to be painted, what a stupendous human tragedy, what a comedy there is to be written with heredity, which is the very genesis of families, of societies, and of the world!” His eyes fixed on vacancy, he remained for a time lost in thought. Then, with an abrupt movement, he came back to the envelopes and, pushing the tree aside, said: “We will take it up again presently; for, in order that you may understand now, it is necessary that events should pass in review before you, and that you should see in action all these actors ticketed here, each one summed up in a brief note. I will call for the envelopes, you will hand them to me one by one, and I will show you the papers in each, and tell you their contents, before putting it away again up there on the shelf. I will not follow the alphabetical order, but the order of events themselves. I have long wished to make this classification. Come, look for the names on the envelopes; Aunt Dide first.” At this moment the edge of the storm which lighted up the sky caught La Souleiade slantingly, and burst over the house in a deluge of rain. But they did not even close the window. They heard neither the peals of thunder nor the ceaseless beating of the rain upon the roof. She handed him the envelope bearing the name of Aunt Dide in large characters; and he took from it papers of all sorts, notes taken by him long ago, which he proceeded to read. “Hand me Pierre Rougon. Hand me Ursule Macquart. Hand me Antoine Macquart.” Silently she obeyed him, her heart oppressed by a dreadful anguish at all she was hearing. And the envelopes were passed on, displayed their contents, and were piled up again in the press.