of the vehicle. It's tafte, it's diuretic quality, it's being fo great a cordial, fhew the activity of this medicine. And at the fame time that it quickensthe fluggish blood of the hysterical, it's balfamic oily nature abates the too rapid motion of the sharp thin blood in those who are hectic. There is a lentour and fmoothnefs in the blood of healthy ftrong people; on the contrary, there is often an acrimony and folution in that of weakly morbid perfons. The fine particles of tar are not only warm and active, they are alfo balfamic and emollient, foftening and enriching the fharp and vapid blood, and healing the erofions occafioned thereby in the blood-veffels and glands. 53. Tar-water poffeffeth the ftomachic and cardiac qualities of Elixir proprietatis, Stoughton's drops, and many fuch tinctures and extracts, with this difference, that it worketh it's effect more fafely, as it hath nothing of that spirit of wine, which, however mixed and difguifed, may yet be well accounted a poifon in fome degree. 54. Such medicines are fuppofed to be diaphoretic, which, being of an active and fubtile nature, pass through the whole fyftem, and work their effect in the fineft capillaries and perfpiratory ducts, which they gently cleanfe and open. Tarwater is extremely well fitted to work by fuch an infenfible diaphorefis, by the fineness and activity of it's acid volatile fpirit. And furely thofe parts ought to be very fine, which can fcour the perfpiratory ducts, under the fcarf fkin or cuticle, if it be true that one grain of fand would cover the mouths of more than a hundred thou-' fand. 55. Another way wherein tar-water operates, is by urine, than which perhaps none is more fafe and effectual, for cleanfing the blood and carrying off off it's falts. But it feems to produce it's principal effect as an alterative, fure and eafy, much fafer than thofe vehement purgative, emetic, and falivating medicines, which do violence to nature. 56. An obftruction of fome veffels caufeth the blood to move more fwiftly in other veffe is, which are not obftructed. Hence manifold diforders. A liquor that dilutes and attenuates, refolves the concretions which obftruct. Tar-water is fuch a liquor. It may be faid, indeed, of common water, that it attenuates, alfo of mercurial preparations that they attenuate. But it should be confidered that mere water only diftends the veffels and thereby weakens their tone; and that mercury, by it's great momentum, may juftly be fufpected of hurting the fine capillaries, which two deobftruents therefore might eafily over-act their parts, and (by leffening the force of the elaftic veffels) remotely produce thofe concretions they are intended to re move. 57. Weak and rigid fibres are looked on by the most able phyficians, as fources of two different claffes of diftempers: a fluggish motion of the liquids occafions weak fibres: therefore tar-water is good to ftrengthen them as it gently accelerates their contents. On the other hand, being an unEtuous bland fluid, it moiftens and foftens the dry and ftiff fibres; and fo proves a remedy for both extremes. 58. Common foaps are compofitions of lixivial falt and oil. The corrofive acrimony of the faline particles being foftened by the mixture of an unctuous substance they infinuate themfelves into the fmall ducts with lefs difficulty and danger. The combination of thefe different fubftances makes up a very fubtile and active medicine, fitted for mixing with all humours, and refolving 1 1 all obftructions. Soap therefore is justly esteemed a moft efficacious medicine in many diftempers. Alcaline foap is allowed to be cleanfing, attenuating, opening, refolving, fweetening; it is pectoral, vulnerary, diuretic, and hath other good qualities, which are alfo to be found in tar-water, It is granted, that oil and acid falts combined together exift in vegetables, and that confequently there are acid foaps as well as alcaline. And the faponaceous nature of the acid vegetable fpirits, is what renders them fo' diuretic, fudorific, penetrating, abfterfive and refolving. Such, for inftance, is the acid fpirit of Guaiacum. And all these fame virtues feem to be in tar-water in a mild and falutary degree. 59. It is the general opinion that all acids coagulate the blood. Boerhaave excepts vinegar, which he holds to be a foap, inafmuch as it is found to contain an oil as well as an acid fpirit. Hence it is both unctuous and penetrating, a powerful antiphlogistic, and prefervative againft corruption and infection. Now it feems evident that tar-water is a foap as well as vinegar. For though it be the character of refin, which is an infpiffated grofs oil, not to diffolve in water (a), yet the falts at tract some fine particles of effential oil; which fine cil ferves as a vehicle for the acid falts, and fhews itfelf in the colour of the tar-water; for all purè falts are colourlefs. And though the refin will not diffolve in water, yet the fubtile oil, in which the vegetable falts are lodged, may as well mix with water as vinegar doth, which contains both oil and falt. And as the oil in tar-water difcovers itself to the eye, fo the acid falts do manifeft (a) Sect. 47. themselves themfelves to the tafte. Tar-water therefore is a foap, and as fuch hath the medicinal qualities of foaps. 60. It operates more gently as the acid falts lofe their acrimony being fheathed in oil, and thereby approaching the nature of neutral falts, are more benign and friendly to the animal fyftem and more effectually, as, by the help of a volatile smooth infinuating oil, thofe fame falts are more eafily introduced into the capillary ducts. Therefore in fevers and epidemical distempers it is (and I have found it fo) as well as in chronical diseases, a most safe and efficacious medicine, being good against too great fluidity as a balfamic, and good against vifcidity as a foap. There is fomething in the fiery corrofive nature of lixivial falts, which makes alcaline foap a dangerous remedy in all cafes where an inflammation is apprehended. And as inflammations are often occafioned by obftructions, it fhould feem an acid foap was much the fafer deobftruent. 61. Even the beft turpentines, however famous for their vulnerary and detergent qualities, have yet been obferved by their warmth to dispose to inflammatory tumours. But the acid fpirit (a) being in fo great proportion in tar-water renders it a cooler and fafer medicine. And the ætherial oil of turpentine, though an admirable drier, healer, and anodyne, when outwardly applied to wounds and ulcers, and not lefs ufeful in cleanfing the urinary paffages and healing their ulcerations, yet is known to be of a nature fo very relaxing as fometimes to do much mischief, when taken inwardly. Tar-water is not attended with the fame ill effects, which I believe are owing in a great measure to the ætherial oil's being deprived of the acid fpirit in diftillation, which vellicating and contracting as a ftimulus might have proved a counterpoife to the exceffive lubricating and relaxing qualities of the oil 62. Woods in decoction do not feem to yield fo ripe and elaborate a juice, as that which is depofited in the cells or loculi terebinthiaci, and fpontaneously oozes from them. And indeed though the balfam of Peru, obtained by boiling wood and fcumming the decoction, be a very valuable medicine and of great account in divers cafes, particularly afthmas, nephritic pains, nervous colies, and obftructions, yet I do verily think (and I do not fay this without experience) that tar-water is a more efficacious remedy in all those cafes than even. that coftly drug. 63. It hath been already obferved, that the reftorative pectoral antihyfterical virtues of the moft precious balfams and gums are poffeffed in a high degree by tar-water (a). And I do not know any purpose answered by the wood drinks, for which tar-water may not be ufed with at least equal fuccefs. It contains the virtues even of Guaiacum which feems the moft efficacious of all the woods, warming and fweetening the humours, diaphoretic and ufeful in gouts, dropfies and rheums, as well as in the foul difeafe. Nor fhould it feem ftrange, if the virtues obtained by boiling an old dry wood prove inferior to thofe extracted from a balfam. 64. There is a fine volatile fpirit in the waters of Geronfter, the most esteemed of all the fountains about Spa, but whofe waters do not bear transporting. The ftomachic, cardiac, and diuretic qualities of this fountain fomewhat refemble thofe of tarwater, which, if I am not greatly mistaken, con (a) Sect. 9, 21, 22, 23. tains |