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chased for a penny a pound, whereas the balsam of Judæa, when most plenty, was sold on the very spot that produced it, for double it's weight in silver, if we may credit Pliny; who also informs us that the best balfam of Judæa Aowed only from the bark, and that it was adulterated with resin and oil of turpentine. Now comparing the virtues I have experienced in car, with those I find ascribed to the precious balm of Judæa, of Gilead, or of Mecha (as it is diversly called) I am of opinion, that the latter is not a medicine of more value or efficacy than the former,
23. Pliny supposed amber to be a refin, and to diftil from some species of pine, which he gathered from it's smell, Nevertheless it's being dug out of the earth shews it to be a foffil, though of a very different kind from other fossils. But thus much is certain, that the medicinal virtues of amber are to be found in the balsamic juices of pines and firs, Particularly the virtues of the most valuable preparation, I mean falt of amber, are in a great degree answered by, tar-water, as a detergent, diaphoretic, and diuretic,
24. There is, as hath been already observed, more or less oil and balsam in all evergreen trees, which retains the acid fpirit, that principle of life and verdure ; the not retaining whereof in sufficient quantity, caufeth other plants to droop and wither, Of these evergreen trees productive of resin, pitch, and tar, Pliny enumerates fix kinds in Europe ; Jonstonus reckons thrice chat number of the pine and fir family. And indeed, their number, their variety, and their likeness makes it difficult to be exact.
25. It is remarked both by Theophrastus and Jonstonus, that trees growing in low and shady places do not yield so good tar, as those which
grow in higher and more exposed situations. And
26. The pines which differ from the firs in the
fir, or picea of the Latins, to be the male fir of Theophrastus. This was probably the spruce fir; for the picea, according to Pliny, yields much resin, loves a cold and mountainous situation, and is diftinguished, tonsili facilitate, by it's fitness to be fhorn, which agrees with the spruce fir, whereof I have seen close shorn hedges.
27. There seems to have been some confusion in the naming of these trees, as well among the ancients as the moderns. The ancient Greek and Latin names are by later authors applied very differently. Pliny himself acknowledgeth, it is not eafy even for the skilful to distinguish the trees by their leaves, and know their sexes and kinds; and that difficulty is since much encreased, by the difcovery of many new species of that evergreen tribe, growing in various parts of the globe. But defa criptions are not so easily misapplied as names. Theophrastus tells us, that witus differeth from arn, among other things, in that it is neither fo tall nor so streight, nor hath so large a leaf. The fir he distinguisheth into male and female: the latter is softer cimber than the male, it is also a taller and fairer tree, and this is probably the silver fir.
28. To say no more on this obscure business which I leave to the critics, I shall observe that according to Theophraftus not only the turpentine trees, the pines, and the firs yield resin or tar, but also the cedars and palm trees; and the words pix and resina are taken by Pliny in so large a sense as to include the weepings of the lentiscus and cypress, and the balms of Arabia and Judæa; all which perhaps are near of kin, and in their most useful qualities concur with common tar, especially the Norvegian, which is the most liquid and best for medicinal uses of any that I have experienced. Those trees that grow on mountains, exposed to
the fun or the north wind, are reckoned by Theophrastus to produce the best and purest tar: And the Idæan pines were distinguished from those growing on the plain, as yielding a thinner, sweeter, and better scented tar, all which differences I think I have observed, between the tar that comes from Norway, and that which comes froin low and swampy countries.
29. Agreeably to the old obfervation of the Peripatetics, that heat gathereth homogeneous things and disperfeth such as are heterogeneous, we find chemistry is fitted for the analysis of bodies. But, the chemistry of nature is much more perfect than that of human art, inasmuch as it joineth to the power of heat that of the most exquisite mechanism. Those who have examined the structure of trees and plants by microscopes, have discovered an admirable variety of fine capillary tubes and vessels, fitted for several purposes, as the imbibing or attracting of proper nourishment, the distributing thereof through all parts of the vegetable, the discharge of superfluities, the secretion of particular juices. They are found to have ducts answering to the tracheæ in animals, for the conveying of air; they have others answering to lacteals, arteries, and veins. They feed, digest, respire, perspire and generate their kind, and are provided with organs nicely fitted for all those uses.
30. The fap vessels are observed to be fine tubes running up through the trunk from the root. Secretory vessels are found in the bark, buds, leaves, and flowers. Exhaling vessels for carrying off excrementitious parts, are discovered throughout the whole surface of the vegetable. And (though this point be not so well agreed) doctor Grew in his Anatomy of plants, thinks there appears
circulation of the fap, moving downwards in the root, and feeding the trunk upwards.
3r. Some difference indeed there is between learned men, concerning the proper use of certain parts of vegetables. But whether the discovererg have rightly guessed at all their uses or no, thus much is certain, that there are innumerable fine and curious parts in a vegetable body, and a wonderful similitude or analogy between the mechanism of plants and animals. And perhaps some will think it not unreasonable to suppose the mechanism of plants more curious than even that of animals, if we consider not only the several juices secreted by different parts of the same plant, but also, the endless variety of juices drawn and formed out of the same foil, by various fpecies of vegetables ; which must therefore differ in an endless variety, as to the texture of their absorbent vefsels and fe.
32. A body, therefore, either animal or vegetable, may be considered as an organised fystem of tubes and vessels, containing several sorts of
Auids. !! And as fluids are moved through the vessels of !, animal bodies, by the fyftole and diastole of the heart, the alternate expansion and condensation of the air, and the oscillations in the membranes and tunicks of the vessels; even so by means of air expanded and contracted in the tracheæ or vessels made up of elastic fibres, the fap is propelled through the arterial tubes of a plant, and the vegetable juices, as they are rarefied by heat or condensed by, cold, will either ascend and evaporate into air, or descend in the form of a gross liquor.
33. Juices therefore, first purified by straining through the fine pores of the root, are afterwards exalted by the action of the air and the vessels of the plant, but, above all, by the action of the sun's