Let the reader imagine Paris lifted off like a cover, the subterranean network of sewers, from a bird’s-eye view, will outline on the banks a species of large branch grafted on the river. On the right bank, the belt sewer will form the trunk of this branch, the secondary ducts will form the branches, and those without exit the twigs.

This figure is but a summary one and half exact, the right angle, which is the customary angle of this species of subterranean ramifications, being very rare in vegetation.

A more accurate image of this strange geometrical plan can be formed by supposing that one is viewing some eccentric oriental alphabet, as intricate as a thicket, against a background of shadows, and the misshapen letters should be welded one to another in apparent confusion, and as at haphazard, now by their angles, again by their extremities.

Sinks and sewers played a great part in the Middle Ages, in the Lower Empire and in the Orient of old. The masses regarded these beds of decomposition, these monstrous cradles of death, with a fear that was almost religious. The vermin ditch of Benares is no less conducive to giddiness than the lions’ ditch of Babylon. Teglath-Phalasar, according to the rabbinical books, swore by the sink of Nineveh. It was from the sewer of Münster that John of Leyden produced his false moon, and it was from the cesspool of Kekscheb that oriental menalchme, Mokanna, the veiled prophet of Khorassan, caused his false sun to emerge.

The history of men is reflected in the history of sewers. The Germoniæ narrated Rome. The sewer of Paris has been an ancient and formidable thing. It has been a sepulchre, it has served as an asylum. Crime, intelligence, social protest, liberty of conscience, thought, theft, all that human laws persecute or have persecuted, is hidden in that hole; the maillotins in the fourteenth century, the tire-laine of the fifteenth, the Huguenots in the sixteenth, Morin’s illuminated in the seventeenth, the chauffeurs[brigands] in the eighteenth. A hundred years ago, the nocturnal blow of the dagger emerged thence, the pickpocket in danger slipped thither; the forest had its cave, Paris had its sewer. Vagrancy, that Gallic picareria, accepted the sewer as the adjunct of the Cour des Miracles, and at evening, it returned thither, fierce and sly, through the Maubuée outlet, as into a bed-chamber.

It was quite natural, that those who had the blind-alley Vide-Gousset, [Empty-Pocket] or the Rue Coupe-Gorge [Cut-Throat], for the scene of their daily labor, should have for their domicile by night the culvert of the Chemin-Vert, or the catch basin of Hurepoix. Hence a throng of souvenirs. All sorts of phantoms haunt these long, solitary corridors; everywhere is putrescence and miasma; here and there are breathing-holes, where Villon within converses with Rabelais without.

The sewer in ancient Paris is the rendezvous of all exhaustions and of all attempts. Political economy therein spies a detritus, social philosophy there beholds a residuum.

The sewer is the conscience of the city. Everything there converges and confronts everything else. In that livid spot there are shades, but there are no longer any secrets. Each thing bears its true form, or at least, its definitive form. The mass of filth has this in its favor, that it is not a liar. Ingenuousness has taken refuge there. The mask of Basil is to be found there, but one beholds its cardboard and its strings and the inside as well as the outside, and it is accentuated by honest mud. Scapin’s false nose is its next-door neighbor. All the uncleannesses of civilization, once past their use, fall into this trench of truth, where the immense social sliding ends. They are there engulfed, but they display themselves there. This mixture is a confession. There, no more false appearances, no plastering over is possible, filth removes its shirt, absolute denudation puts to the rout all illusions and mirages, there is nothing more except what really exists, presenting the sinister form of that which is coming to an end. There, the bottom of a bottle indicates drunkenness, a basket-handle tells a tale of domesticity; there the core of an apple which has entertained literary opinions becomes an apple-core once more; the effigy on the big sou becomes frankly covered with verdigris, Caiphas’ spittle meets Falstaff’s puking, the louis-d’or which comes from the gaming-house jostles the nail whence hangs the rope’s end of the suicide. A livid fœtus rolls along, enveloped in the spangles which danced at the Opera last Shrove-Tuesday, a cap which has pronounced judgment on men wallows beside a mass of rottenness which was formerly Margoton’s petticoat; it is more than fraternization, it is equivalent to addressing each other as thou. All which was formerly rouged, is washed free. The last veil is torn away. A sewer is a cynic. It tells everything.

The sincerity of foulness pleases us, and rests the soul. When one has passed one’s time in enduring upon earth the spectacle of the great airs which reasons of state, the oath, political sagacity, human justice, professional probity, the austerities of situation, incorruptible robes all assume, it solaces one to enter a sewer and to behold the mire which befits it.

This is instructive at the same time. We have just said that history passes through the sewer. The Saint-Barthélemys filter through there, drop by drop, between the paving-stones. Great public assassinations, political and religious butcheries, traverse this underground passage of civilization, and thrust their corpses there. For the eye of the thinker, all historic murderers are to be found there, in that hideous penumbra, on their knees, with a scrap of their winding-sheet for an apron, dismally sponging out their work. Louis XI. is there with Tristan, François I. with Duprat, Charles IX. is there with his mother, Richelieu is there with Louis XIII., Louvois is there, Letellier is there, Hébert and Maillard are there, scratching the stones, and trying to make the traces of their actions disappear. Beneath these vaults one hears the brooms of spectres. One there breathes the enormous fetidness of social catastrophes. One beholds reddish reflections in the corners. There flows a terrible stream, in which bloody hands have been washed.

The social observer should enter these shadows. They form a part of his laboratory. Philosophy is the microscope of the thought. Everything desires to flee from it, but nothing escapes it. Tergiversation is useless. What side of oneself does one display in evasions? the shameful side. Philosophy pursues with its glance, probes the evil, and does not permit it to escape into nothingness. In the obliteration of things which disappear, in the watching of things which vanish, it recognizes all. It reconstructs the purple from the rag, and the woman from the scrap of her dress. From the cesspool, it reconstitutes the city; from mud, it reconstructs manners; from the potsherd it infers the amphora or the jug. By the imprint of a finger-nail on a piece of parchment, it recognizes the difference which separates the Jewry of the Judengasse from the Jewry of the Ghetto. It re-discovers in what remains that which has been, good, evil, the true, the blood-stain of the palace, the ink-blot of the cavern, the drop of sweat from the brothel, trials undergone, temptations welcomed, orgies cast forth, the turn which characters have taken as they became abased, the trace of prostitution in souls of which their grossness rendered them capable, and on the vesture of the porters of Rome the mark of Messalina’s elbowing.