Notwithstanding the care taken to shore them up, the roofs of the abandoned quarries still give way occasionally under the superincumbent weight. In May, 1879, a house in the Passage Gourdon, Boulevard Saint-Jacques, sank through the earth; in the following year, a tree in the Luxembourg garden, near the Médicis fountain, did the same thing, and in July of this year, 1880, the lightning fell in this garden, and at almost the same moment two houses in the Boulevard Saint-Michel began to sink, as well as a large section of the sidewalk. These events naturally produced a great excitement in the quarter, and measures were taken to prevent a possible recurrence of such happenings. Proprietors proposing to build in these suspected districts are now required to conform to certain regulations of the inspector-general of quarries, who examines the subsoil under their properties. [Illustration: PARTY OF STUDENTS LUNCHING DURING A VISIT TO THE CATACOMBS. Engraved from a flash-light photograph.] The Cimetière des Saints Innocents,--said to have dated from the time of Philippe-Auguste,--which thus contributed to the first furnishing of the catacombs, was one of the institutions of mediæval Paris. Surrounded by its arcades of _charniers_, it had long been one of the most popular resorts of the city, and the Danse Macabre, earlier than the famous one at Bâle, painted along fifteen of these arcades, with inscriptions "to incite the people to devotion," only incited them to dance themselves. It was believed that the Duc de Berry had caused these paintings to be executed after the assassination of the Duc d'Orléans, the king's brother, in 1407, and the verses written under each personage were attributed to Jean Gerson, who was "inspired by serious contemplation to appeal, by the presentation of death, to his contemporaries of this fifteenth century--so abounding in calamities of every nature." The contemplation of death ceased to appal them,--for the space of six months, from August, 1424, to Lent, 1425, the people were in the habit of assembling in the cemetery on Sundays and fête-days, grotesquely attired to represent various classes of society, and, led by a mask disguised as Death, dancing frantically over the graves and along the charniers heaped with skeletons. In this _ronde infernale_ might be recognized some obnoxious abbot, or procureur, or bourgeois, or serjent, travestied and caricatured; the people, "seeking for the moment to forget their cares and sorrows, mocked at that death which they no longer scarcely feared, for it was, at this disastrous epoch, very often for them a deliverance." Too close familiarity with the _Camard_--"the flat-nosed," the death's-head--had bred the proverbial lack of respect.