Dr. Lyon Playfair states as follows in his communication—
There are two kinds of changes which animal and vegetable matters undergo, when exposed to certain influences. These are known by the terms of “decay” and “putrefaction.” Decay, properly so called, is a union of the elements of organic matter with the oxygen of the air; while putrefaction, although generally commencing with decay, is a change or transformation of the elements of the organic body itself, without any necessary union with the oxygen of the air. When decay proceeds in a body without putrefaction, offensive smells are not generated; but if the air in contact with the decaying matter be in any way deficient, the decay passes into putrefaction, and putrid smells arise. Putrid smells are rarely if ever evolved from substances destitute of the element nitrogen.
Both decaying and putrefying matters are capable of communicating their own state of putrefaction or of decay to any organic matter with which they may come in contact. To take the simplest case, a piece of decayed wood, a decaying orange, or a piece of tainted flesh is capable of causing similar decay or putrefaction in another piece of wood, orange, or flesh. In a similar manner the decaying gases evolved from sewers occasion the putrescence of meat or of vegetables hung in the vicinity of the place from which they escape. But this communication of putrefaction is not confined to dead matter. When tainted meat or putrescent blood-puddings are taken as food, their state of putrefaction is frequently communicated to the bodies of the persons who have used them as food. A disease analogous to rot ensues, and generally terminates fatally. Happily this disease is little known among us, but it is of very frequent occurrence in Germany.
The decay or putrefaction communicated by putrid gases or by decaying matters does not always assume one form, but varies according to the organs to which their peculiar state is imparted. If communicated to the blood it might possibly happen that fever may arise; if to the intestines, dysentery or diarrhœa might result; and I think it might even be a question worthy of consideration, whether consumption may not arise from such exposure. Certainly it seems to do so among cattle. The men who are employed in cleaning out drains are very liable to the attacks of dysentery and of diarrhœa; and I recollect instances of similar diseases occurring among some fellow-students, when I attended the dissecting-rooms.
The effects produced by decaying emanations will vary according to the state of putrefaction or decay in which these emanations are, as well as according to their intensity and concentration. Thus it occurs frequently that persons susceptible to contagion may be in the vicinity of a fever patient without acquiring the disease. I know one celebrated medical man who attends his own patients in fever without danger, but who has never been able to take charge of the fever-wards in an infirmary, from the circumstance of his being unable to resist the influence of the contagion under such circumstances. This gentleman has had fever several times. This shows that the contagion of fever requires a certain degree of concentration before it is able to produce its immediate effects. A knowledge of this circumstance has induced several infirmaries (the Bristol infirmary, for example) to abolish altogether fever-wards and to scatter the fever cases indiscriminately through the medical wards. Owing to this distribution, cases in which fever is communicated to other patients or nurses in the infirmary are very unfrequent, although they are far from being so in those hospitals where the fever cases are grouped together.
I consider that the want of attention to the circumstance of the concentration of decaying emanations is a great reason that the effects of miasmata in producing fever is still a questio vexata. Thus there may be many church-yards and sewers evolving decaying matter, and yet no fever may occur in the locality. Some other more modified effect may be produced, according to the degree of concentration of the decaying matter, such as diarrhœa or even dysentery; or there may be no perceptible effects produced, although the blood may still be thrown into a diseased state which will render it susceptible to any specific contagion that approaches. It must be remembered that decaying exhalations will not always produce similar effects, but that these will vary not only according to the concentration, but also according to the state of decomposition in which the decaying matters are.
The rennet for making cheese is in a peculiar state of decay, or rather is capable of a series of states of decay, and the flavour of the cheese manufactured by means of it varies also according to the state of the rennet. Just so with the diseases produced by the peculiar state or concentration of decaying matters or of specific contagions. When the Asiatic cholera visited this country many of the towns were afflicted with dysentery before the cholera appeared in an unquestionable form. In like manner the miasmata evolved from church-yards may produce injurious effects which may not be sufficiently marked to call attention until they assume a more serious form by becoming more concentrated. But notwithstanding the absence of marked effects, it is extremely probable that constant exposure to miasmata may produce a diseased state of the blood. Thus I had occasion to visit and report upon, amongst other matters, the state of slaughter-houses in Bristol. These are generally situated in courts, very inefficiently ventilated, as all courts are. I remarked that the men employed in the slaughter-houses had a remarkably cadaverous hue, and this was participated in a greater or less degree by the inhabitants of the court. So much was this the case, that in a court where the smells from the slaughter-house were so offensive that my companion had immediately to retire from sickness, I immediately singled out one person as not belonging to the court from a number of people who ran out of their houses to inquire the object of my visit. The person who attracted my attention from her healthy appearance compared with the others, had entered this court to pay a visit to a neighbour.
§ 11. That conclusions respecting such immensely important effects can only be established by reasonings on facts frequently so scattered over distant times and places as to require much research to bring them together; that those conclusions are still open to controversy, and have hitherto been maintained only by references to statements of distant observations, whilst regularly sustained examinations of the events occurring daily in our large towns might have placed them beyond a doubt; may be submitted as showing the necessity of some public arrangements to ensure constant attention, and complete information on these subjects, as the basis of complete measures of prevention.
§ 12. The conclusions, however, which appear to be firmly established by the evidence, and the preponderant medical testimony, are on every point, as to the essential character of the physical evils connected with the practice of interment, so closely coincident with the conclusions deduced from observation on the continent, that from Dr. Riecke’s report (and to which a prize was awarded by an eminent medical association), in which the preponderant medical opinions are set forth, they may be stated in the following terms:—
“The general conclusions from the foregoing report may be given as follows: