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Show 128‘TheVegeraion | —BookIIL. BookIII. running from the Bargue tow ards the Centre of the Root, and ‘fo paf= fing along betwixt the Aer-Veffels ; do hereby convey the Acry Part ofthe Sup from the Barque, ito the fame. Cana? te Le Of the Structure ofthe Parts, 7. §. Being thus received into the Aer-} effels, and the Receptior thereof, by the fame means continued5 it is by them advanced into the Truzk, In which advance, it Is again, more or lefs, disburfedinto all the Parts of the Trunk, as it goes. Partly, inwards to the Pith, From whence, the P7th is always, at length, filled with Aer, Partly, into the Ixfertions 5 by whichit is conveyed outward into the Bargue. Pe THIRD enquiry, is into the Geverat ion and Strudure of Parts. The manner whereof I have already endeavoured to explicate (4) fromthe 4- (4) Lib. 2, natomyOf the Root, throughout all particulars, : 2. Wherein, it is in fome part, transfufed through the Sap : and fo the reft, with part of the Sap, remitted, in per/pirations, back again into the Aer. ENS 8. §. So that, whereas the Diametral Portions in the Root, do ferve toconvey the Aer from the Sp in the Barque, into the AerVefels, in the Wood: on the contrary, the Infertions here in the Trunk , ferve to conveythe Aer from the Aer-Vefels in the Wood, into the Sap, inthe Bargue. Wherefore, as the Aer-Vefféls advance the Aer, or the Aery Part ofthe Sap, and fo conveyit by the /ength of the Trunks fo the Infertions filter it, and conveyit by the breadth. 9. §. AND that the Infertions have this Office or Subfervience unto both Kinds of Vefels5 doth yet further appear, if we confider, That the Aer-Vefels are always fo poftured, asto touch upon the {aid Infertions, or at \eaft to ftand very near them. For either theyare large, and fo do frequently touch upon them onbothfides; as in Ela, Afh,, Wallaut, &c. Or if theyare {mall 5 then they either run along in evenlines collateral and oftentimes contiguous with the faid Infertions, asin Holly: or at leaft, are reciprocally, fome on one fide, and fome on another, inclined to them; as in Apple. By all which means, the Aer is more readily conveyed from the Vefels into the Iv- Jertions. to. g. A further evidence hereofis this, That generally, the bigger and the more numerous the Aer-Vefels be; the bigger, or at leaft, the more numerousalfo are the Infertions : Efpecially, if the comparifon bemade (asin all other cafes it ought to be, as well as here ) betwixt the feveral Species of the fame Kind. So Corin, which hath {mall Aer-Vefféls, hath alfo veryfmall Ixfertions. But the Vine, hath both verylarge: and fo for others. 11. Wherefore, the Ivfértions minifter betwixt the Aer-Veffels, and the Succiferovs 5 inthe fame manner, as the Veficule of the Lungs, do betwixt the Bronchie and the Arteries. That is to fay, asin an Avimal, the Bronchie depofite the Aer into the Veficule of the Lungs; which adminifter it to the Arteries: fo ina Plant, the Aer-Veffels depofit the Aer intothe Infértions, that’ isinto the Veficule ofthe Infertions 5 by which it is gradually jiltred off into the Bargue and the Sap-Veffels therein. Some whereof I fhall yet furtherclear, 1. §. As Firft, the Union of the Barque to the eés Body of the Tree, Contrary to the common OpiThat they are not continuous; but that the Barque only faurroun ds the Body, asa Scabbard does a Sword, or aGlove the Hand. As alfo feemeth to be proved, by the ealy Slipping of the Barque of Willow, and moft other Trees, whenfall of Sap, from the Wood, 2. §. But, notwithftanding this, theyare as truly continuous, as the Skin ofthe Body is with the Fle(h: fc. by meansofthe Parenchyma whichis one entire Body, running from the Bargue into the Wood, and fo uniting both together; as ina Branch of Vine or Corin-Tree, when the Barque is {tripped off, is apparent ; the Spaces between the feveral Parts of the Wood, beingfilled up with the Parenchymous, inferted from the Bargue. 3. §. Nowthe reafon why the Barque neverthelef flips fo eafily from the Wood, is plain, viz. Becaufe moft ofthe young Veffels and Pa- renchjmous Parts, are there every year fucceffively formed ; that is, be- twixt the Wood and Barque: where the {aid Parts newlyformed, are as tender, as the tendereft Veféls in Animals. And we may imagine, howeafie it were at once to tear or break a thoufand Yefels or Fibres of an Ezbrio, of a Womb orEge. 4. §. THE fameVefels of the Barque being always braced, and graduallyfalling off, together with the Parexchyma, into the utmoft re _ ale Rind : Henceit is, that the Barques of many Trees, are as ait were, lat- 7 Tab. 19: ticed with feveral Cracks of divers Sizes,and fometimes in the Figure of Rombs: the faid Fiffures reprefenting the Poftion and Traé of the Veffels in their Braces. Hence alfo it is, that the Barque of fome Trees, as of Corin, Cherry, &c. falleth off in Rings, fc. becaufe the Sap-Veffels are pofited in the fame mannerin the Barque. 5. §. The Sap-Veffels, as they are generated at the inner Verge of the Bargue. fo likewife, in a fmall quantity, at the utmoft Verge of the Pith. Thefe being not only fed with a more vigorous Sap, but with great caution, fecured within the Wood, for the propagation of the fucceeding Buds. 6. §. Hence alfo it is, that is, by the annual accretion of thefe Veffels,chat the Pithis fometimes lef in the Truwk, than in the Branches ; Tab, and lefs in the elder Branches, than in the youuger; and fometimes ‘tis allmoft wholly filled up. By which means, as the Branches carry every year a greater burthen; fothey become {till more fturdy the better to fupport it. 7. § SOMETIMES alfothePith breaks and fhrinks up, thus making the Trunk a Pipe. The caufe whereof, is either the Largenefs of its Pores, or the Thinne/s of the Sides of the faid Pores 5 uponboth Z which wale atJ i |