The drainage of air from drains is, indeed, desirable under any circumstances; but when the usual contaminations of the drain are increased by the emanations from a loaded churchyard, it becomes doubly imperative to introduce such measures; and if any one should desire to trace the progress of reaction by which the grave-yards are continually tending to free themselves of their contents, a very brief inquiry will give him abundant evidence on this point. My attention was first directed to this matter in London ten years ago, when a glass of water handed to me at an hotel, in another district, presented a peculiar film on its surface, which led me to set it aside; and after numerous inquiries, I was fully satisfied that the appearance which had attracted my attention arose from the coffins in a churchyard immediately adjoining the well where the water had been drawn. Defective as our information is as to the precise qualities of the various products from drains, church-yards, and other similar places, I think I have seen enough to satisfy me that in all such situations the fluids of the living system imbibe materials which, though they do not always produce great severity of disease, speedily induce a morbid condition, which, while it renders the body more prone to attacks of fever, is more especially indicated by the facility with which all the fluids pass to a state of putrefaction, and the rapidity with which the slightest wound or cut is apt to pass into a sore.
Mr. Leigh, surgeon and lecturer of chemistry at Manchester, confirms the researches made by Dr. Reid in that town, and observes on this subject—
But the decomposition of animal bodies is remarkably modified by external circumstances where the bodies are immersed in or surrounded by water, and particularly, if the water undergo frequent change, the solid tissues become converted into adipocire, a fatty spermaceti-like substance, not very prone to decomposition, and this change is effected without much gaseous exhalation. Under such circumstances nothing injurious could arise, but under ordinary conditions slow decomposition would take place, with the usual products of the decomposition of animal matters, and here the nature of the soil becomes of much interest. If the burial-ground be in damp dense compact clay, with much water, the water will collect round the body, and there will be a disposition to the formation of adipocire, whilst the clay will effectually prevent the escape of gaseous matter. If on the other hand the bodies be laid in sand or gravel, decomposition will readily take place, the gases will easily permeate the superjacent soil and escape into the atmosphere, and this with a facility which may be judged of when the fact is stated, that under a pressure of only three-fourths of an inch of water, coal gas will escape by any leakage in the conduit pipes through a stratum of sand or gravel of three feet in thickness in an exceedingly short space of time. The three feet of soil seems to oppose scarcely any resistance to its passage to the surface; but if the joints of the pipes be enveloped by a thin layer of clay, the escape is effectually prevented.
If bodies were interred eight or ten feet deep in sandy or gravelly soils, I am convinced little would be gained by it; the gases would find a ready exit from almost any practicable depth.
§ 22. He also expresses an opinion concurrent with that of other physiologists, that the effects of these escapes in an otherwise salubrious locality, soon attract notice, but their influence in obedience to the laws of gaseous diffusion, developed by Dalton and Graham, is not the less when scattered over a town, because in a multitude of scents they escape observation. In open rural districts these gases soon intermix with the circumambient air, and become so vastly diluted that their injurious tendency is less potent.
Other physical facts which it is necessary to develope in respect to the practice of interment may be the most conveniently considered in a subsequent portion of this report, where it is necessary to adduce the information possessed, as to the sites of places of burial, and the sanitary precautions necessary in respect to them.
§ 23. From what has already been adduced, it may here be stated as a conclusion,
That inasmuch as there appear to be no cases in which the emanations from human remains in an advanced stage of decomposition are not of a deleterious nature, so there is no case in which the liability to danger should be incurred either by interment (or by entombment in vaults, which is the most dangerous) amidst the dwellings of the living, it being established as a general conclusion in respect to the physical circumstances of interment, from which no adequate grounds of exception have been established;—
That all interments in towns, where bodies decompose, contribute to the mass of atmospheric impurity which is injurious to the public health.