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pafs the lacteals and other finer veffels, nor yet, perhaps, readily impart thofe virtues to a menftruum, that may with fafety and speed convey them throughout the human body. Upon all which accounts, I believe tar-water will be found to have fingular advantages. It is obferved that acid fpirits prove the stronger, by how much the greater degree of heat is required to raife them. And indeed, there feemeth to be no acid more gentle than this, obtained by the fimple affufion of cold water; which carries off from the fubject the moft light and fubtile parts, and, if one may fo fpeak, the very flower of it's fpecific qualities. And here it is to be noted, that the volatile falt and spirit of vegetables do, by gently stimulating the folids, attenuate the fluids contained in them, and promote fecretions, and that they are penetrating and active, contrary to the general natureof other acids.

51. It is a great maxim for health, that the juices of the body be kept fluid in a due proportion. Therefore, the acid volatile fpirit in tarwater, at once attenuating and cooling in a moderate degree, muft greatly conduce to health, as a mild falutary deobftruent, quickening the circulation of the fluids without wounding the folids, thereby gently removing or preventing those obftructions, which are the great and general cause of moft chronical difeafes; in this manner answering to the antihyfterics, affa foetida, galbanum, myrrh, amber, and, in general, to all the refins and gums of trees or fhrubs ufeful in nervous cafes.

52. Warm water is it felf a deobftruent. Therefore the infufion of tar drunk warm, is easier infinuated into all the nice capillary veffels, and acts, not only by virtue of the balfam, but alfa by that

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of the vhicle. 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 quickens the fluggish blood of the hysterical, it's balfamic oily nature abates the too rapid motion of the sharp thin blood in thofe who are hectic. There is a Jentour and fmoothnefs in the blood of healthy trong 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 emolFient, foftening and enriching the sharp 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 fpirit of wine, which, however mixed and difguifed, may yet be well accounted a poifon in fome degree.

54. Such medicines are fuppofed to be diapho retic, which being of an active and fubtile nature, pafs 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 thoufand.

55. Another way wherein tar-water operates, is by urine, than which perhaps none is more fafe and effectual, for cleaning 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 veffels, which are not obftructed. Hence manifold diforders. A liquor that dilutes and attenuates refolves the concretions which obftruct. Tar-water is fuch a li-' quor. It may be faid, indeed, of common water, that it attenuates, alfo of mercurial preparations that they attenuate. But it fhould 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 easily overact their parts, and (by deffening the force of the elaftic veffels) remotely produce thofe concretions they are intended to

remove.

57. Weak and rigid fibres are looked on by the most able physicians, 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 unAtuous bland fluid it moiftens and foftens the dry and stiff 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 fubftance they infinuate themselves into the fmall ducts with lefs difficulty and danger. The combination of these different fubftances makes up a very fubtile and active medicine, fitted for mixing with all humours, and refolving

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all obftructions. Soap therefore is justly esteemed a most efficacious medicine in many diftempers. Alcaline foap is allowed to be cleansing, 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 oyl and acid falts combined together exist 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, absterfive 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, inafimuch as it is found to contain an oyl as well as an acid fpirit. Hence it is both unctuous and penetrating, a powerful antiphlogistic, and prefervative against 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 oyl, not to diffolve in water (a), yet the falts attract fome fine particles of effential oyl: which fine oyl ferves as a vehicle for the acid falts, and fhews itself in the colour of the tar-water; for all pure falts are colourlefs. And though the refin will not diffolve in water, yet the fubtile oyl, in which the vegetable falts are lodged, may as well mix with water as vinegar doth, which contains both oyl and falt. And as the oyl in tar-water difcovers felf to the eye, fo the acid falts do manifeft

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themselves 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 oyl, and thereby approaching the nature of neutral faits, are more benign and friendly to the animal fyftem: and more effectually, as by the help of a volatile smooth infinuating oyl, thofe fame falts are more eafily introduced into the capillary ducts. Therefore in fevers and epidemical diflempers it is (and I have found it fo) as well as in chroni cal diseases, a moft fafe 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 obstructions, it should feem an acid foap was much the fafer deobftruent.

61. Even the best turpentines, however famous for their vulnerary and detergent qualities, have yet been obferved by their warmth to difpofe 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 oyl of turpentine, though an admirable dryer, healer, and anodyne, when outwardly applyed to wounds and ulcers, and not lefs ufeful in cleansing the urinary paffages and healing their ulcerations, yet is known to be of a nature fo very relaxing as fometimes to do much mischief. Tar-water is not attended with the fame ill effects, which I believe are owing in a great measure to the ætherial oyls being deprived

(a) Sect. 7, 8.

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