What we are here chiefly to examine is, how from Ingredients singly Innocent and Harmless, so Mischievous a Compound can result; for as the Case is very plain with respect to _Salt_, so is it likewise now Notorious enough, that _Quick-silver_ it self, which the Ancients, _Dioscorides_, _Galen_, _Pliny_, &c. have unjustly rank’d among Poisons, is in many Diseases inwardly taken of very safe and beneficial Use; and that not only when disguised with _Sulphur_, _Sugar_, &c. but _Crude_, without any Correction, or vainly pretended Mortification. This the _Arabian_ Physicians first gave the hint of; _Avicen_, (117) having observ’d, that _They who drink It in a large quantity receive no hurt, its weight making a free Passage thro’ the Body_. This was Incouragement enough for the Practice of giving whole Pounds of It in the _Iliac Passion_; which is oftentimes done with good Success, without any frightful Symptom accompanying the Advantage receiv’d from its Ponderosity. Afterwards it plainly appear’d that this Mineral, tho’ not taken in so great a Dose as could immediately force its way thro’ the Intestins, even when it was lodged for some time in this or that Part, was not at all hurtful by any Corrosive or Malignant Quality. And _Fallopius_ (118), _Brasavolus_ (119), with others of great Note, confirmed its harmless Efficacy in the Cure of the _Worms_, not only in adult Persons, but even in the more tender Constitutions of Children. Nor are these the only Cases in which good Service may be had from this Weighty Fluid; he that rightly considers the State of the Animal _Oeconomy_, the various Alterations it suffers from the Stagnation of its more Viscid Juices in the smallest Canals, and how much the Impulse and Force of the Circling Blood, by which Obstructions are to be removed, must be increased by its carrying along with it such Particles as the _Mercurial Globuli_, will perhaps see good Reason to allow, that the prudent and cautious Management of _Quicksilver_ may do that in some obstinate and dangerous Diseases, which we cannot promise our selves from any other of our known Medicines whatsoever. 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.