§ 159. The retention of bodies in leaden coffins in vaults is objected to, as increasing the noxiousness of the gases, which sooner or later escape, and when in vaults beneath churches, create a miasma which is apt to escape through the floor, whenever the church is warmed.[31] In Austria, and in other states, interment in lead is prohibited. In the majority of cases in England, burial in lead, as well as in other expensive coffins, appears to be generally promoted by the undertakers, to whom they are the most profitable. The Emperor Joseph, of Austria, on the knowledge of the more deleterious character of concentrated emanations from the dead, forbade the use even of coffins, and directed that all people should be buried in sacks; but this excited discontent amongst his subjects, who agreed in the sanitary principle of the measure, but complained that, putting them in sacks, was treating them as the Turks would do, and the regulation was altered for burial in coffins made of pine, which decays rapidly. § 160. It is to be observed as an improved direction of the public mind in the British metropolis, that on the part of persons who have the means of defraying the expenses of vaults, an increasing preference of inhumation is manifested, and that it is found by cemetery companies that catacombs prepared for sale are not so much in demand as was anticipated from the proportion in which they were in demand in the parochial burial grounds. The state of some of the places of common burial has evidently been such as to lead to the practice of entombment in preference to inhumation. The associations commonly expressed with inhumation (_redditur enim terræ corpus, et ita locatum ac situm, quasi operimento matris obducitur_, Cic. de legibus) were with a purer earth. In the most carefully regulated cemeteries in Germany the sale of any portions in perpetuity is entirely prohibited. The recent investigation of the disorders which have arisen in the management of the Parisian cemeteries, has led to a conclusion for the adoption of the same regulation, it having been found that, in time, families become extinct, or fall into decay; that a proportion of the tombs and vaults are neglected and fall into ruins, and detract from the general good keeping of the rest. Under such circumstances the private tombs too frequently raise associations of a character the very opposite of those intended by the purchasers. Their numbers at the same time increase and continually encroach on the spaces for general burial, and would ultimately occupy the whole of the cemeteries; and in the progress of population would absorb and hold large tracts of most important land near towns, in what would literally be one of the worst species of mortmain.[32] It has, therefore, been found necessary to restrict the sale of perpetuities in vaults or graves, and to give only what may be called leases for years, renewable on conditions, for the public protection.