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acid spirit in Tar-water possesseth the virtues, in an eminent degree, of that of guaiacum, and other medicinal woods.

48. Qualities in a degree too strong for human nature to subdue, and assimilate to itself, must hurt the constitution. All acids, therefore, may not be usesul or innocent. Bun this seemeth an acid so thoroughly concocted, so gentle, bland, and temperate, and withal a spirit so fine and volatile, as readily to enter the smallest vessels, and be assimilated with the utmost ease.

49. If any one were minded to dissolve some of the resin, together with the salt or spirit, he need only mix some spirit of wine with the water. But such an intire solution of resins and gums, as to qualify them for entering and pervading the animal system, like the sine acid spirit that first flies off from the subject, is perhaps impossible to obtain. It is an apophthegm of the chemists, derived from Helmont, that whoever can make myrrh soluble by the human body, has the secret of prolonging his days : and Boerhaave owns that there seems to be truth in this, from it's resisting putresaction. Now this quality is as remarkable in tar, with which the ancients embalmed and preserved dead bodies. And though Boerhaave himself, and other chemists before him, have given methods for making solutions of myrrh, yet it is by means of alcohol which extracts only the inflammable parts. And it doth not seem that any solution of myrrh is impregnated with it's salt or acid spirit. It may not, therefore, seem strange if this water should be found more beneficial for procuring health and long life, than any solution of myrrh whatsoever.

50. Certainly divers resins and gums may have virtues, and yet not be able for their grosihess to

1 pals pass the lacteals and other finer vessels, nor yet, perhaps, readily impart those virtues to a menstruum, that may with safety and speed convey them throughout the human body. Upon all which accounts, I believe tar- water will be found to have singular advantages. It is observed that acid spirits prove the stronger, by how much the greater degree of heat is required to raise them. And indeed, there seemeth to be no acid more gentle than this, obtained by the simple affusion of cold water; which carries off from the subject tha most light and subtile parts, and, if one may so speak, the very flower of it's specific qualities. And here it is to be noted, that the volatile salt and spirit of vegetables do, by. gently stimulating the solids, attenuate the fluids contained in them, and promote secretions, and that they are penetrating and active, contrary to the general nature of 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 spirit in tarwater, at once attenuating and cooling in a moderate degree, must greatly conduce to health, as a mild salutary deobstruent, quickening the circulation of the fluids without wounding the solids, thereby gently removbg or preventing those obstructions, which are the great and general cause of most chronical diseases ; in this manner answering to the antihysterics, assa feetida, galbanum, myrrh, amber, and, in general, to all the resins and gums of trees or shrubs usesul in nervous cases.

52. Warm water is it self a deobstruent. Therefore the insusion of tar drunk warm, is easier insinuated into all the nice capillary vessels, and acts, not only by virtue of the balsam, but also by thac

D or of the vehicle. It's taste, it's diuretic quality, it's being so great a cordial, shew the activity of this medicine. And at the fame time that it quickens the sluggish blood of the hysterical, it's balsamic oily nature abates the too rapid motion' of the sharp thin blood in those who are hectic. There is a lentour and smoothness in the blood of healthy strong people; on the contrary, there is often an acrimony and solution in that of weakly morbid persons. The fine particles of tar are not only warm and active, they are also balsamic and emollient, softening and enriching the sharp and vapid blood, and healing the erosions occasioned thereby in the blood-vessels and glands.

53. Tar-water possesseth the stomachic and cardiac qualities of Elixir proprietatis, Stoughton's drops, and many such tinctures and extracts, with this difference, that it worketh it's effect more safely, as it hath nothing of that spirit of wine, which, however mixed and disguised, may yet be well accounted a poison in some degree.

54. Such medicines are supposed to be diaphoretic, which, being of an active and subtile nature, pass through the whole system, and work their effect in the finest capillaries and perspiratory ducts which they gently cleanse and open. Tarwater is extremely well fitted to work by such an insensible diaphoresis, by the fineness and activity of it's acid volatile spirit. And surely those parts ought to be very fine, which can scour the perspiratory ducts, under the scarf skin or cuticle, if it be true that one grain of sand would cover the mouths of more than a hundred thousand.

55. Another way wherein tar-water operates, is by urine, than which perhaps none is more safe and effectual, for cleansing the blood and carrying

I of* off it's salts. But it seems to produce it's principal effect as an alterative, sure and easy, much safer than those vehement purgative, emetic, and salivating medicines, which do violence to nature.

56. An obstruction of some vessels caufeth the blood to move more swiftly in other vessels, which are not obstructed. Hence manifold disorders. A liquor that dilutes and attenuates resolves the concretions which obstruct. Tar-Water is such a liquor. It may be said, indeed, of common water, that it attenuates, also of mercurial preparations that they attenuate. But it should be considered that mere water only distends the vessels and thereby weakens their tone; and that Mercury by it's great momentum may justly be suspected of hurting the fine capillaries, which two deobstruents therefore might easily overact their parts, and (by lessening the force of the elastic vessels) remotely

. produce those concretions they are intended to remove.

57. Weak and rigid fibres are looked on by the most able physicians, as sources of two different classes of distempers: a sluggish motion of the liquids occasions weak fibres: therefore tar-water is good to strengthen them as it gently accelerates their contents. On the other hand, being an unctuous bland fluid it moistens and softens the dry and stiff fibres: and so proves a remedy for both extremes.

58. Common soaps are compositions of lixivia! salt and oil. The corrosive acrimony of the saline particles being softened by the mixture of an unctuous substance they insinuate themselves into the small ducts with less difficulty and danger. The combination of these different substances makes up a very fubtife and active medicine, fitted for rilixing with all humours, and resolving

D 2 < all aIl obstructions. Soap therefore is justly esteemed a most efficacious medicine in many distempers. Alcaline Soap is allowed to be cleansing, attenuating, opening, resolving, sweetening; it is pectoral, vulnerary, diuretic, and hath other good qualities -which are also to be found in tar-water. It is granted, that oil and acid salts combined together exist in vegetables, and that consequently there are acid soaps as well as alcaline. And the saponaceous nature of the acid vegetable spirits, is what renders them so diuretic, sudorific, penetrating, abstersive and resolving. Such, for instance, is the acid spirit of Guaiacum. And all these same virtues ieem to be in tar-water in a mild and salutary degree.

59. It is the general opinion that all acids coagulate the blood. Boerhaave excepts vinegar, which he holds to be a soap, inasmuch as it is found to contain an oil as well as an acid spirit. Hence it is both unctuous and penetrating, a powerful antiphlogistic, and preservative against corruption and infection. Now it seems evident that tar-water is a soap as well as vinegar. For though it be the character of refin, which is an inspissated gross oil, not to dissolve in water (a), yet the salts attract some fine particles of estential oil: which fine oil serves as a vehicle for the acid salts, and shews itself in the colour of the tar-water-, for all pure salts are colourless. And though the resin will not dissolve in water, yet the subtile oil, in which the vegetable salts are lodged, may as well mix -with water as vinegar doth, which contains both oil and salt. And as the oil in tar-water discovers itself to the eye, so the acid salts do manifest

(a) Sect. 47.

themselves

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