A 



The bark fervcs divers purpOr:'3, for it not only tranf- 

 mits the nutritious juices ot the plant, but alio con- 

 tains divers fat oily humours to defend the flelhy parts 

 fronn the injuries of the weather. 

 6. As aninn.als are furnifhcd with a panniculus adl- 

 pofus, ufually replete with fat, which inveft and covers 

 all the flelhy parts, and fcreens them from external 

 cold, fo are plants encompaffed with a bark replete 

 v/ith far juices, by the means v/hereof the cold is 

 kept out, and in winter time the fpiculae of ice pre- 

 vented froni fixing and freezing the juices in their 

 vcfTels ; whence it is, that fome forts of trees remiain 

 evergreen the year round, by reafon their barks have 

 more oil than can be fpent and exhaled by the fun, 

 . and their leaves are covered v^^ith a thick oily film 

 over their fjrface, which prevents their perfpiring fo 

 much <is other plants, and alfo defends them from the 



. cold, &c. 

 All the juices of barks are reducible to eight, viz. 



1. The crude, acid, watery juice, called the chyle of 

 , the plant. 



2. An oily juice, which, burfting the bark in the be- 

 ginning of tlie fummer, exfudes cut of feveral plants, 

 as Cyprcls, Pine, Fir, Savin, Juniper, and other ever- 



. greens, and fuch ^lone. This oil diffolves by the fmall- 

 eft degree, of v/armth, and is eaiily inflamed, and is 

 that v/hich defends the plant, which is the reafon why 

 moft of thefe plants will not thrive in very hot cli- 

 mates. 

 por balm, or fatty liquor, more glutinous than oil, is 



. nothing but the laft mentioned oily juice, which was 



more fluid during the fpring time, but which, by the 



greater heat of the fun, has evaporated all its moft: 



fubtile parts, and is converted into a denfer liquor. 



Thus the finer part of oil of Olives being exhaled by 



the fummer's warmth, there remains a thick balfam 



behind : thus alfo oil of turpentine, having loft its 



more liquid parts by heat, becomes of the thick con- 

 . fifl:enceof a balm. . '," ^^-. ri^r.-^-^r^vi^itii- 1?^ 



3. A pithy juice, which is the body of theVil itfelf, 

 - . infpiffates, and turns black, wheif put int6 a gr^at 



; warmth : this is the moft obferved in the Pine and Fir. 

 5. Refin, which is an oil fo far infpiffated, as to be- 



It io 



ob 



between the juices, which have not undergone the 

 action of thole parrs, and li;ch as have alreadV circu- 

 lated a numl>er of rimes. 



The feveral juices hitherto recounted are tlie firll or 

 nutritious juice, called alfo the chyle of the plant, un- 

 der fuch alterations, and new modificatioiis, as it un- 

 dergoes in being received, and kept fome time, m 

 parrs of a peculiar llruclure, as leaves, flower, feed 

 ike. This lafl: juice, called the blood, is the fame nu- 

 tritious juice farther altered, by being divers times 

 paflTed through each of thefe parts, and re-mixed, and 

 at length converted into a new juice, with properties 

 difltrrent from any of them all. 

 To prove the circulation of the Sap, inftances are 

 brought from experiments made by Mr. Fairchild,^as 

 his budding and inoculating of a Paflion-tree, whofe 

 leaves are fpotted with yellow, into one of that fort of - 

 Pafllon-tree whofe leaves are plain ; for thouc^h the 

 buds did not take, yet 'after it had been budded a 

 fortnight, the yellow fpots began to fhew themfelvcs 

 about three feet above the inoculation, and in a little 

 time after that, the yc-I-w ipots appeared on a fhoot, 

 which cam.e out of the ground from another part of 

 the plant, which has been accounted a plain proof of 

 the Sap's circulation. 



Another infl:ance is, another experiment of the fame 

 perfon, who grafted the evergreen Oak, or Ilex, up- 

 on the common Oak. The leaves of the common 

 Oak, which was the ftock, decayed, and fell off at 

 the ufual feafon of the year, but the evergreen Oak, 

 which was the cyon grafted upon it, held its leaves, 

 and continued fliooting in tlie winter ; from whence ic 



, is concluded, that when trees drop their leaves, the 



• fap keeps full in motion, and is not gone into the 



" root^ as fome perfons think. 

 There are alfo other experiments of the fame perfon, 



-whicli were ftiewn before the Royal Society, as the 



■^t 



J 



■ -the Virginian, and what is taken to prove the circu- 

 lation in it, is, the branch which was grafted was left 

 feveral inches below the grafting, which continued 

 growing as well 4§ the upper part abdVe the grafting. 

 \ come friable in the cold, may be procured from any \. -And alio another, which is the Viburnum, with the 



_ . , - - .. ^'top planted in the ground, which was become roots, 



- . tine be fet over a' gentle fire, Ml firft diffolves, and" be- " and the roots turned up, which were become branches ; 



;'-Avhich plant was in as good a ftate of growing, as it 

 was in its natural ftate. ■ * - 



oil by boiling it much and long. ' Thus, if turpen- 

 tine be fet over a' gentle fire, Ml firft diffolves, and be- 

 . corhes ari^oil, then a balfann, then pitch, and then a 

 : refin, in which ftate it is friable in the cold, fufible 

 : by fire, withal inflammable and combuftible, diflblu- 

 ble in fpirit of wine, but not in water, which makes 

 ■ the charafter of refin. 

 Hence the oil is muft abundant in the barks in the 

 winter time, the balfams in fummer, and the refin in 

 - autumn. ' 



A third experiment of his was on a Pear-tree, which 

 he inarched upon two Pear ftocks in March 1721-2, 

 having the roots out of the ground, and was in a 

 good flourilhing ftate, with a branch in bloflbm, 

 that receives no other nourifliment but by the juices 

 that return down the other two branches, whiph, 



6. Colophony, which is a refin ftill farther exhaufted I though it had been done above two years, continued 

 of its volatile part, being pellucid/ friable, and ap- [ fhooting fuckers out of the root; which is cftechied 



as a proof, that the branches are as ufeful to fuppbrt 

 the roots, as the roots the branches, and tlierice he 



\ proaching to the nature of glafs, '^^^^ 



7. Gum, which is an humour exfuding but of the 



bark, and, by the warmth of the fun, concofted, in- I infers, that it is not ftrange that fo many trees mif- 



fpifl^ated, ^nd rendered tenacious, but ftill diflToluble carry in planting, when there are no branches left to 



in water, and at the fame time inflammable, and 

 I fcarce capable of being pulverized. This oily muci- 

 lage ferves as a pigment to cover over, and defend 



btjd 



and 



.: tun from them, when tfie gentle warmth of the fpring 

 V approaches, nor is ever fo far hardened into a cruft, as 



to do any injury to theinclofed fhoot. This oilyfub- 

 ^ ftance always contains in it an acid fpirit, which is a 

 vprefcrvative again ft putrefaction.- -■■■ - '^ 



8. A gummous refin, which is an humour fecreted in 

 <the bark, and dried by the heat of the fun, and thus 

 . ^ conftituting a body that is partly gummous, and, as 



• luch, tenacious, foluble in water, partly refinous, and 

 therefore friable, and foluble in oil, or fpirit of wine, 



* but not in water. 



f Botanifts are now generally agreed, that all plants 

 , are fumifheH with organs and parts necefl^ary both 

 for chyhfication^and fanguification, that they have 



adipofe cellules, &c. 



vems, arteries, heart, lungs, 



- ^' 



1 



I ' 



\ 



the head to maintain the circulation to the roots. 

 ;A fourth experiment he made on the Cedar of Leba- 

 nusj^ grafted on the Larix, which drops its leaves in 

 the winter, yet maintained the Cedar in a flourifhing 

 -condition, as if it had been oh a tree which held its 

 leaves all the winter, and the circulation of juices fup- 

 ported the graft below the grafting, and kept it in as 

 good health as above the grafting. ':' ' 

 In oppofition to the notion of the circulation of 

 the Sap in trees like that in animal bodies, the Re- 

 . verend Dr. Hales, in his excellent Treatife on Vege- 

 table Statics, prefents us with various experiments, 

 and fays. 



When the Sap has firft pafl^ed through that thick and 

 fine ftrainer, the bark of the root, we then find it 

 reateft quantities in the moft lax part between the 

 and wood, and that the fame through the whole 



tree^ • 



And if in the early fpring, the Oak; and feveral other 



trees, were to be examined near the top and bottom, 



. >- when 



^ r 



. 3. 



