But I am not to insist on this Head; and the learned Author of the New Theory of Fevers [(120)], has already most ingeniously explain’d the Mechanism by which such Effects as these are produced in the humane Body. It suffices to my present purpose, to have proved that pure Mercury is not Poisonous or Corrosive; and therefore not only have I seen Two Ounces of It given every Day for One and Twenty Days together, without any Inconvenience at all; but found once some quantity of It in the Perinæum of a Subject I took from the Gallows for a Dissection (whose rotten Bones quickly discovered what Disease it was had required the Use of it, and that I suppose chiefly in External Application by Unction) without any Marks of Corrosion of the Part where it was lodged.
Tho’ withal we may upon this Occasion remark, that the extreme Gravity of this Mineral alone, however serviceable it may be in other Respects; yet when it happens in so great a Quantity to Obstruct the Capillary Ducts, as that the Force of the Circling Fluid is not sufficient to Wash it away, must necessarily induce Symptoms troublesome and bad enough, as Spasms, Contractions, Palsies, &c. which They do commonly Experience, who have either been too often dawbed with Mercurial Ointments, or for a long time imploy’d in rubbing the Quicksilver upon Looking-Glasses; for the Internal Use of It will never produce any such Mischiefs.
As for Sublimate then, most certain it is, that the Saline Particles do impart to the Mercury this Malignant Quality; or to speak more properly, That the Salt receives from the Mercurial Corpuscles such an Increase of its Gravity and Momentum, as renders its Cutting Corrosion more Effectual and Penetrating; for the manner after which this Matter is done, is plainly this.
The Globules of the Mercury, tho’ so minutely divided by the Action of the Fire, as to rise in the form of a Fume, yet are still Solid and Ponderous Bodies; ’tis all one to the present purpose, whether We suppose ’em perfectly Sphærical, or with the Learned Gulielmini [(121)] Sphæroidical, for in both Cases, by reason of their extreme Parvity, being perhaps Simple and Elementary Bodies, they will easily be lodg’d in the Pores and Interstices of the Saline Crystals; which being compos’d of the Atoms of Salt, variously by Sublimation combin’d and united, are a kind of Cutting Lamellæ or Blades; the force of which could never have been very penetrating, upon the account of their Lightness and easie Dissolution, if the Mercury, without blunting their Edge, or breaking their Figure, did not lend ’em an Additional Weight, and thus at the same time strengthen their Action, and prevent their quick Solution by the Juices of the Stomach; which cannot now disjoin their Compounding Parts, because the Vacuities into which they should, in order to do this, insinuate themselves, are already possess’d, and taken up by the Mercurial Globules.
In short, These Crystals, which are to be considered as so many sharp Knives or Daggers, Wounding and Stabbing the tender Coats of the Stomach, and thus causing excessive Pains, with an Abrasion of their Natural Mucus, and (upon the constant Sense of Irritation) continual Vomitings, &c. must of necessity, sticking here and there in the capillary Vessels, stop the Passage of the Blood in several Places, whereupon it Stagnates, and there follow little Inflammations, which growing higher and higher, terminate quickly in perfect Ulcers and Gangrenes; and these though singly very small, yet many in number, do all together make up one continued and incurable Mortification.
This being the Nature of Sublim’d Mercury, it may not be amiss to enquire, how it comes to pass, That This same Compound resublim’d with live Mercury in the Proportion of Four Parts to Three, (for the Sublimate will not take up an equal quantity) especially if the work be repeated Three or Four times, looses its Corrosiveness to that Degree as to become not only a Safe, but in many Cases, a Noble Medicine. For I do not see that any of the Chymical Writers have hit upon the true Solution of this Phænomenon.
Here then it is to be considered, That the Action of the Saline Crystals depending upon their Solidity and Largeness, these must necessarily, by every subsequent Sublimation, be broken into smaller and smaller Parts; the Mercurial Globules (for the Reasons given by the Author [(122)] of the forementioned Theory of Fevers) arising more quickly and easily than the Salts, quit the Interstices in which they were lodged, and the Crystalline Blades are divided every time more and more by the force of the Fire; whereupon a new Combination of Parts succeeds; and although there be a greater Proportion of the Mineral to the Salts than before, which makes Dulcify’d Mercury Specifically heavier than the Corrosive; yet the broken pieces of the Crystals uniting into little Masses of differing Figures from their former Make, those Cutting Points which were before so sharp, are now either quite lost, or at least, by reason of their Bluntness, cannot make Wounds deep enough to be equally mischievous and deadly; and therefore do only Vellicate and Twitch the sensible Membranes of the Stomach to that Degree, as excites them to an Excretion of their Contents and Glandular Juices, upwards or downwards, according as the force of Irritation is greater or less.
Thus a violent Poison is mitigated into a Vomit or Purge; nay, it may easily happen (especially in Robust Constitutions, and if the Bowels be at the same time by any means defended against the Stimulating Power of the Medicine) that this Twitching may be so slight, as to be almost insensible, and hardly troublesome; and then the Mercurial Globules being freed indeed from most of the Saline Parts in their Passage thro’ the Primæ Viæ, but still having a mixture of some few of them, are quickly conveyed into the Blood, where by their Motion and Weight they must necessarily dissolve the Preternatural Cohæsions of all the Liquors, particularly of Those which Circulate in the smallest Canals, and are most Viscid and Tenacious, making ’em more Fluxile and Thin, or of more easie Secretion; whereupon all the Glands of the Body are, as it were, set to Work, and Scoured of their Contents; but the Salival Ones especially, being many in Number, very large and wide, and the Juice they separate of a Tough and Ropy Substance, so that a considerable quantity of It is accumulated before it is forced out at the Orifices of the Ducts. These Effects will be most remarkable in Them, and a Salivation or Spitting must continue so long, till the Active Mineral Particles are thro’ these and the other Passages discharged out of the Body.
As the Difference between Mercury Corrosive and Dulcified lies in a greater and lesser Degree of Operation and Force, so this same Consideration distinguishes the several Preparations of this Mineral from each other; which tho’ very many, yet do all vary their Effects in the Body, only according as the Mercurial Globules are differently combined with Salts, and the Points of These more or less broken by the Action of the Fire, in the Burning of Spirits upon Them, and such like Managements: And therefore however dignified with the great Names of Arcana, Panacææ, Princes Powders, &c. They do not afford Us any thing Singular and Extraordinary, beyond what we may with equal Advantage promise our selves from some or other of the most common and usual Processes.
We may also fairly conclude from this Reasoning, that the safest way of raising a Salivation is by Internal Medicines; since whatever Mischiefs can be apprehended from These, may in a greater degree follow from the External Use of Mercury; not only because, as We have already hinted, the Mineral Globules being intimately combined with Salts in the several Preparations given inwardly, will by the Irritation of These, be easily and fully thrown out at the Organs of Secretions, till the Blood is quite discharged of its Load; whereas, in all the Dawbings with Mercurial Ointments, We can never be certain that none of the heavy Particles are left lodg’d in the Interstices of the Fibres or Cells of the Bones; But also, in as much as by computing the Portion of Mercury in all the Doses necessarily to promote a Spitting, and the Weight of the same Mineral usually apply’d when this is done by Unction, it will appear, that the quantity in the latter Case vastly exceeds that in the former, and consequently that the Inconveniencies to be feared will be in the same proportion.