114. After having faid fo much of the ufes of tar, I must farther add, that being rubb'd on them it is an excellent prefervative of the teeth and gums; that it sweetens the breath, and that it clears and trengthens the voice. And, as its effects are various and useful, fo there is nothing to be feared from the operation of an alterative fo mild and friendly to nature. It was a wife maxim of certain ancient philofophers, that difeafes ought not to be irritated by medicines. But no medicine difturbs the animal œconomy lefs than this (a), which, if I may trust my own experience, never produces any disorder in a patient when rightly taken. 115. I knew indeed a perfon who took a large glafs of tar-water juft before breakfaft, which gave him an invincible naufea and difguft, although he had before received the greateft benefit from it.' But if the tar-water be taken and made in the manner prefcribed at the beginning of this effay, it will, if I mistake not, have enough of the falt to be ufeful, and little enough of the oil to be inoffensive. I mean my own manner of making it, and not the American; that fometimes makes it too ftrong, and fometimes too weak; which tar-water, however it might ferve as there ufed, merely for a preparative against the fmall-pox, yet I queftion whether it may be fitly used in all thofe various cafes wherein I have found tar-water fo fuccessful. Perfons more delicate than ordinary may render it palatable, by mixing a drop of the chemical oil of nutmegs, or a fpoonful of mountain wine in each glafs. It may not be amifs to obferve, that I have known fome, whofe nice ftomachs could not bear it in the morning, take it at night going to bed without any inconvenience; and that with fome it agrees best warm, with others cold. It may be (a) 133. made made stronger for brute beafts, as horfès, in whose disorders I have found it very useful,. I believe more fo than that bituminous fubftance call'd Barbadoes tar. 116. In very dangerous and acute cafes much may be taken and often; as far as the ftomach can bear. But in chronical cafes, about half a pint, night and morning, may fuffice; or in cafe fo large a dofe fhould prove difagreeable, half the quantity may be taken at four times, to wit, in the morning, at night going to bed, and about two hours after dinner and breakfaft. A medicine of fo great virtue in fo many different diforders, and especially in that grand enemy, the fever, muft needs be a benefit to mankind in general. There are nevertheless three forts of people to whom I would peculiarly recommend it: Sea-faring perfons, ladies, and men of studious and fedentary lives. 117. To failors and all fea-faring perfons, who are fubject to fcorbutic diforders and putrid fevers, efpecially in long fouthern voyages, I am perfuaded this tar-water would be very beneficial. And this may deserve particular notice in the prefent courfe of marine expeditions, when fo many of our country-men have perifhed by fuch diftempers, contracted at fea and in foreign climates. Which, it is probable, might have been prevented, by the copious ufe of tar-water. 118. This fame water will alfo give charitable relief to the ladies (a), who often want it more than the parish poor; being many of them never able to make a good meal, and fitting pale, puny, and forbidden like ghofts, at their own table, victims of vapours and indigestion. 119. Studious perfons alfo pent up in narrow holes, breathing bad air, and ftooping over their (a) 103. I books, books, are much to be pitied. As they are debarred the free ufe of air and exercife, this I will venture to recommend as the beft fuccedaneum to both. Though it were to be wifhed, that modern fcholars would, like the ancients, meditate and converse more in walks and gardens and open air, which, upon the whole, would perhaps be no hindrance to their learning, and a great advantage to their health. My own fedentary courfe of life had long fince thrown me into an ill habit, attended with many ailments, particularly a nervous cholic, which rendered my life a burthen, and the more fo, becaufe my pains were exafperated by exercife. But fince the ufe of tar-water, I find, though not a perfect recovery from my old and rooted illness, yet fuch a gradual return of health and eafe, that I efteem my having taken this medicine the greatest of all temporal bleffings, and am convinced that, under providence, I owe my life to it. 120. In the diftilling of turpentine and other balfams by a gentle heat, it hath been obferved, that there rifeth firft an acid fpirit (n) that will mix with water; which fpirit, except the fire be very gentle, is loft. This grateful acid fpirit that firit comes over, is, as a learned chemist and phyfician informs us, highly refrigeratory, diuretic, fudorific, balfamic or prefervative from putrefaction, excellent in nephritic cafes, and for quenching thirst, all which virtues are contained in the cold infufion, which draws forth from tar only it's fine flower or quinteffence, if I may fo fay, or the native vegetable fpirit, together with a little volatile oil. 121. The diftinguishing principle of all vegetables, that whereon, their peculiar finell, tafte, and fpecific properties depend, feems to be fome extremely fine and fubtile fpirit, whofe immediate vehicle is an exceeding thin volatile oil, which is itfelf detained in a groffer and more vifcid refin or balfam, lodged in proper cells in the bark and feeds, and most abounding in autumn or winter, after the crude juices have been thoroughly 'concocted, ripened, and impregnated with folar light. The fpirit itself is by fome fuppofed to be an oil highly fubtilized, fo as to mix with water. But fuch volatile oil is not the fpirit, but only it's vehicle. Since aromatic oils, being long expofed to air, will lose their specific fmell and tafte, which fly off with the spirit or vegetable falt, without any fenfible diminution of the oil. pre 122. Those volatile falts, that are fet free and raised by a gentle heat, may juftly be supposed effential (a), and to have pre-exifted in the vegetable; whereas the lixivial fixed falts obtained by the incineration of the fubject, whofe natural conftituent parts have been altered or destroyed by the extreme force of fire, are by later chemifts, upon very good grounds, fuppofed not to have exifted therein; all fuch falts appearing, from the experiments of fignor Redi, not to preserve the virtues of the refpective vegetable fubjects; and to be alike purgative and in an equal degree, whatsoever may be the fhape of their points, whether sharp or obtufe. But although fixed or lixivious falts may not contain the original properties of the fubject; yet volatile falts raised by a flight heat from vegetables are allowed to preserve their native virtues: and fuch falts are readily imbibed by water. 123. The moft volatile of the falts, and the moft attenuated part of the oil, may be fuppofed (a) 8. the the first and readieft to impregnate a cold infufion (b). And this will affift us to account for the virtues of tar-water. That volatile acid in vegetables, which refifts putrefraction, and is their great prefervative, is detained in a fubtile oil mifcible with water, which oil is itself imprisoned in the refin or groffer part of the tar, from which it is eafily fet free and obtained pure by cold wa ter. 124. The mild native acids are obferved more kindly to work upon, and more thoroughly to diffolve, metallic bodies, than the ftrongest acid fpirits produced by a vehement fire; and it may be fufpected, they have the fame advantage as a medicine. And as no acid, by the obfervation of fome of the best chemifts, can be obtained from the fubftance of animals thoroughly affimilated, it fhould follow, that the acids received into a healthy body must be quite fubdued and changed by the vital powers: but it is easier to fubdue and affimilate (e) the gentler than the ftronger acids. 125. I am very fenfible, that on fuch fubjects arguments fall fhort of evidence: and that mine fall fhort even of what they might have been, if I enjoyed better health, or thofe opportunities of a learned commerce, from which I am cut off in this remote corner. I fhall nevertheless go on as I have begun, and proceed by reafon, by conjecture, and by authority, to caft the beft light I can on the obfcure paths that lie in my way. 126. Sir Ifaac Newton, Boerhaave, and Homberg are all agreed, that the acid is a fine fubtile fubftance, pervading the whole terraqucous globe; which produceth divers kinds of bodies, as it is united to different fubjects. This according to (b) 1, i 2 (e) 48 1, Homberg |