Regarding the extent to which the soil is affected in consequence of burials, we are in possession of exact and well-established facts. The time required for the earth fully to transform organic matter that may be buried in it varies according to the physical and chemical nature of the soil: in some grounds bodies are, we might say, devoured in a few days; more commonly the time required to transform a corpse is estimated at from five years, as in Paris, to twenty years, as at Geneva, and even more in some places. Authors also differ respecting the time needed for the operation: Gmelin and Wildberg believed that it takes thirty years, while Maret thought that three years are enough.
Legislation based on this point has designated a variety of periods after which burial-grounds may be used over again. At Frankfort, thirty years is the standard; at Leipsic, fifteen years; at Milan and Stuttgart, ten years; at Munich, nine years. Generally, the time necessary for a complete destruction of the body is estimated in France at five years, but this limitation is not at all absolute, and in many cases burial-grounds may be used anew before that time. In the majority of the experiments made by them, Orfila and Lesueur found that bodies were reduced to skeletons at the end of fourteen, fifteen, or eighteen months. After that time, the soil under the vivifying influence of oxygen resumed its original qualities.
On this point, we may assert, contrary to certain affirmations, but in accordance with experiments the importance and value of which are guaranteed by the name of the author, M. Schützenberger, that, so far as the cemeteries of Paris are concerned, no saturation of the soil, either with gases or with solids, exists. The recent experiments of this chemist have resulted, in effect, in showing that the soil in the Parisian cemeteries is still in a sufficiently favorable condition as to its composition to effect the absorption of the gases and the complete transformation of the solid and liquid matters resulting from the putrefaction of the bodies that may be buried in them. The analysis, so far as it refers to gases at least, has given identical results with the analyses of good arable lands. Moreover, there is nothing to prevent the modification of the soil of cemeteries by means of suitable applications for augmenting the intensity and rapidity of its combustible force. Such applications are certainly not beyond the means of modern agricultural chemistry.
No important instance of the contamination of waters has been established against the cemeteries. Cases of an exceptionally unfavorable influence of a mass of decomposing matter on certain waters may occasionally occur, but none such have been established in the soils of Paris, and those which have been described in other places are not conclusive. What, on the contrary, most evidently comes out after a study of the facts is the remarkable purifying power that the earth possesses. It would take too long to give here the proof that water is not infected by cemeteries; we mention only the case of the well in