On the action of various absorbents as promoting or retarding putrefaction.
The whimsical and ill-grounded hypotheses which were framed by the chymists of the sixteenth century, had, unhappily, too much influence, on the medical practice of that and the succeeding age. Among other false theories which the physicians had adopted from them, was that of attributing the origin of most diseases either to an acid or alkaline cause: but the former, being more obvious to the senses, was supposed to be the most frequent parent of diseases. Among others, fevers, even of the putrid kind, were imagined to be occasioned by an acid, and from hence the testaceous medicines acquired so high a degree of reputation, as to be deemed the grand correctors of acrimony, and were almost universally prescribed as alexipharmics; and the most celebrated compositions which are ranged under that head, contain a large proportion of these powders.
But a very learned physician, by a series of accurate and ingenious experiments on septics and antiseptics, has proved that chalk and all the testaceous powders accelerate the corruption of animal flesh, and from the result of one he made on bile with crab's eyes, he naturally concluded that all these substances would produce the same effect on that humour, as they had all uniformly proved septic to flesh. Yet, even upon this supposition, he candidly allows, that in some fevers, they may have their uses, even where no offending acid exists; as in order to cure some diseases, it may be requisite to attenuate the humours, and relax the fibres by a degree of putrefaction, and that possibly the crisis of fevers of this kind, may be hastened or perfected by the testaceous powders. In diseases, however, where the disposition to putrescency is already too strong, all medicines, which in the smallest degree increase such tendency should be studiously avoided; and, on this account, the administration of the testacea in putrid, malignant fevers has of late been condemned by some ingenious writers. I was myself fully convinced of the rectitude of this opinion, and, in drawing up an account of the medicinal uses of Magnesia, had therefore suggested the impropriety of prescribing them where a bilious acrimony prevails. But not being able to recollect, that the septic powers of Magnesia had ever been experimentally proved,[r] I thought it would be most satisfactory to determine them by that method; little doubting but that the event would justify my doctrine. My inquiries evince the accuracy with which Sir John Pringle has made his experiments, but as I was induced to carry the investigation of this subject further than he has proceeded, very different practical inferences, from those I at first expected, may, perhaps, be deduced therefrom.
EXPERIMENT II.
Two drachms of fresh beef, two scruples of Magnesia, and two ounces of distilled water were mixed in one bottle; and in another the same quantity of beef with two ounces of distilled water only: the meat was cut small, and the bottles were placed uncorked in a heat rather inferior to that of the human blood. In twenty four hours the beef in the mixture with Magnesia was become quite putrid. The standard was perfectly sweet, and remained for some days, before it acquired the true putrid fœtor.
Being thus convinced that Magnesia is possessed of the property of hastening the putrefaction of animal flesh, in common with the rest of the absorbent tribe, it was imagined, that it might be of some consequence to practice, to determine how far it exceeded or was inferiour to the calcareous and testaceous earths as a septic; and also whether calcination produced any difference in it, in this respect. In reciting the experiments, where I only mention Magnesia, I always would be understood to mean that powder in its uncalcined state, the calcined shall constantly be distinguished by that epithet. It also appeared to be a convenient opportunity of repeating the inquiry, how far the addition of the testacea might take effect in diminishing the antiseptic qualities of the contrayerva root.
EXPERIMENT III.
Into one phial were put two scruples of Magnesia, into a second the same weight of calcined Magnesia, and into three others the same quantity of chalk, pulv. e chel. cancr. comp. and pulv. contrayerv. comp. To each of these, two drachms of fresh beef, and two ounces of distilled water were added. A sixth phial was kept as a standard, and contained only the same proportions of beef and water. The bottles, distinguished in the order they are mentioned by the numbers 1, 2, 3, 4, 5, and 6, were placed in the same heat as that to which the Magnesia was exposed in the former experiment, and were frequently shaken up and examined.
In twelve hours, number 1 began to smell; an intestine motion was perceptible in numbers 3, 4, 5, and 6, but especially in the chalk. In twenty-four hours, number 1 was become highly putrid, number 3 smelled offensively, number 4 had acquired a very slight fœtor, as had number 5 which fermented briskly. The standard had acquired a vinous smell, but number 2 remained unchanged.
In thirty six hours, number 3 was very putrid, numbers 4 and 5 had made little progress since the last examination, though number 5 was rather more putrid than the other, allowance being made for the peculiar odour of the contrayerva; but in four hours more they both stunk intolerably. The standard continued two or three days longer before it became absolutely putrid, and the calcined Magnesia preserved the beef untainted for several days longer, when it was removed to make room for other phials. The water which was mixed with the calcined Magnesia differed from all the others in not becoming bloody, nor did the beef in it seem so tender as when infused in lime water.