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languishes at his recess ; this terrestrial globe seeming only a matrix disposed and prepared to receive life from his light ; whence Homer in his hymns ftileth earth the wife of heaven, ănox' ovqævé csepbevlos.

44. The luminous fpirit which is the form or life of a plant, from whence it's differerces and properties fow, is somewhat extremely volatile. It is not the oil, but a thing more subtile, whereof oil is the vehicle, which retains it from flying off, and is lodged in several parts of the plant, particularly in the cells of the bark and in the feeds. This oil purified and exalted by the organical powers of the plant, and agitated by warmth, becomes a proper receptacle of the spirit ; part of which fpirit exhales through the leaves and flowers, and part is arrested by this unctuous humour that detains it in the plant. It is to be noted this effen. tial oil animated, as one may say, with the favour of the plant, is very different from any spirit, that can be procured from the same plant by fermentation.

45. Light impregnates air (a), air impregnates vapour ; and this becomes a watery juice by diftillation having risen first in the cold still with a kindly gentle heat. This fragrant vegetable water is poffeffed of the specific odour and taste of the plant. It is remarked that distilled oils added to water for counterfeiting the vegetable water can never equal it, artificial chemistry falling short of the natural.

46. The less violence is used to nature the better it's produce. The juice of olives or grapes ifsuing by the lightest preffure is best. Resins that drop from the branches spontaneously, or ooze upon the Nightest incision, are the finest and moft

(a) 37. 43.

fragrant.

fragrant. And infusions are observed to act more strongly than decoctions of plants, the more subtile and volatile salts and spirits, which might be Joft or corrupted by the latter, being obtained in their natural itate by the former. It is also observed that the finest, purest, and most volatile part is that which first ascends in distillation. And, indeed, it should seem the lightest and most active particles required least force to disengage them from the subject.

47. The falts, therefore, and more active spirits of the tar are got by infusion in cold water : but the resinous part is not to be dissolved thereby (a). Hence the prejudice which some perhaps may entertain against Tar-water, as a medicine, the vse whereof might infame the blood by it's sulphur and resin, appears to be not well grounded; it being indeed impregnated with a fine acid fpirit, ballamic, cooling, diuretic, and possessed of many other virtues (b). Spirits are lupposed to consist of salts and phlegm, probably too somewhat of a fine oily nature, differing from oil in that it mixeth with water, and agreeing with oil,

in that it runneth in rivulets by distillation. Thus - much is allowed, that the water, earth, and fixed falt are the same in all plants ; that, therefore, which differenceth a plant or makes it what it is, - the native spark or form, in the language of the chemists or schools, is none of those things, nor yet the finest oil, which seemeth only it's receptacle or vehicle. It is observed by chemists, that all sorts of balsamic wood afford an acid spirit, which is the volatile oily falt of the vegetable : Herein are chiefly contained their medicinal virtues, and by the trials I have made it appears, that the

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acid spirit in Tar-water poffefseth 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 useful or innocent. But 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 veffels, and be affimilated with the utmost ease.

49. If any one were minded to diffolve fome 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 fine acid fpirit 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 refifting putrefaction. 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 infiammable parts. And it doth not seem that any folution of myrrh is impregnated with it's falt or acid fpirit. It may not, therefore, seem ftrange if this water should be found more beneficial for procuring health and long life, than any folution of myrrh whatsoever.

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

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pals the lacteals and other finier vessels, hot gets perhaps, readily impart those virtues to a mena Itruum, that may with safety and fpeed 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 'ral e them. And indeed, there seeinech to be no acid more gentle than this, obtained by the fimple atfusion of cold water ; which carries off from the subject the most light and subtile parts, and, it 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 folids, 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 Auid 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 deobītruent, quickening the circula* tion of the Auids without wounding the folids, thereby gently removing or preventing those obstructions, which are the great and general caufe of most chronical diseases ; in this manner answers ing to the antihyfterics, asfa foetida, galbanum, myrrh, amber, and, in general, to all the tesins and gums of trees or ihrubs ufeful in nervous cases.

52. Warm water is it self a deobftruent. Therefore the infusion of tar drunk warm, is cafier iofi- :: nuaced into all the nice capillary vefsels, and acts, not only by virtue of the balfam, but also by chat

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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 same 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 poffeffech 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 nore safely, as it hath nothing of that spirit of wine, which, however mixed and disguised, may yet be well accounted a poison in fome 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 fpirit. And surely those parts ought to be very fine, which can fcour the perfpiratory 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 thoufand.

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

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