CHAP. III.
Of the TRUNK.
AVING thus declar’d the degrees of Vegetation in the Root; the continuance hereof in the Trunk shall next be shew’d: in order to which, the Parts whereof this likewise is compounded, we shall first observe.
1. §. That which without dissection shews it self, is the Coarcture: I cannot say of the Root, nor of the Trunk; but what I choose here to mention, as standing betwixt them, and so being common to them both; all their Parts being here bound in closer together, as in the tops of the grown Roots of very many Plants, is apparent.
2. §. Of the Parts of the Trunk, the first occurring is its Skin: The Formation whereof, is not from the Air, but in the Seed, from whence it is originated; being the production of the Cuticle, there investing the two Lobes and Plume.
3. §. The next Part is the Cortical Body; which here in the Trunk is no new substantial Formation; but, as is that of the Root, originated from the Parenchyma of the Plume in the Seed; and is only the increase and augmentation thereof. Tab. 3. f. 1, & 4. The Skin, this Cortical Body or Parenchyma, and (for the most part) some Fibers of the Lignous mixed herewith, altogether make the Barque.
4. §. Next, the Lignous Body, which, whether it be visibly divided into many softer Fibers or small Threads, as in the Bean, Fennel, and most Herbs; Tab. 3. f. 1. or that its Parts stand more compact and close, shewing one hard, firm and solid piece, as in Trees; it is, in all, one and the same Body; and that not formed originally in the Trunk, but in the Seed; being nothing else but the prolongation of the Seminal Root distributed in the Lobes and Plume thereof.
5. §. Lastly, The Insertions and Pith are here originated likewise from the Plume, as the same in the Root, from the Radicle: So that as to their Substantial Parts, the Lobes of the Seed, the Radicle and Plume, the Root and Trunk are all one.
6. §. Yet some things are more fairly observable in the Trunk. First, the Latitudinal shootings of the Lignous Body, which in Trunks of several years growth, are apparent in so many Rings, as is commonly known. For several young Fibers of the Lignous Body, Tab. 3. f. 5, & 8. as in the Root, so here, shooting in the Cortical one year, and the spaces betwixt them being after fill’d up with more (I think not till) the next, at length they become altogether a firm compact Ring; the Perfection of one Ring, and the Ground-work of another, being thus made concomitantly.
7. §. From these Annual younger Fibers it is, that although the Cortical Body and Pith are both of the same substantial nature, and their Pores little different; yet whereas the Pith, which the first year is green, and of all the Parts the fullest of Sap, becomes afterwards white and dry: The Cortical Body, on the contrary, so long as the Tree grows, ever keepeth green and moist, sc. because the said Sap-Fibers, annually grow therein, and so communicate with it.
8. §. The Pores likewise of the Lignous Body, many of them, in well-grown Timber, as in Oaken boards, are very conspicuous, in cutting both lengthwise and traverse. They very seldom, if ever, run one into another, but keep, like so many several Vessels, all along distinct; Tab. 3. f. 2. & 3. as by cutting, and so following any one of them as far as you please, for a Foot or half a Yard, or more together, may be observ’d. And so, the like, in any Cane.
9. §. Besides these, there are a lesser sort; which, by the help only of a good Spectacle Glass may be observ’d.
10. §. And these are all the Pores visible without a Microscope. The use of which, excepting in some few particulars, I have purposely omitted in this first Book. Micrography. Mr. Hook sheweth us, besides these, a third, and yet smaller Sort; and (as a confirmation of what, in the Second Chapter, C. 2. §. 8. I have said of the Pores of the Lignous Body in general) that they are all continuous and prolonged by the length of the Trunk, as are the greater ones: whereof he maketh Experiment, by filling up, in a piece of Char-coal, all the said Pores with Mercury; which appears to pass quite through them, in that by a very good Glass it is visible in their Orifices at both ends; and without a Glass, by the weight of the Coal alone, is also manifest. All these I have seen, with the help of a good Microscope, in several sorts of Woods.Tab. 3. f. 7. As they all appeare in a piece of Oak, cut transversely, See Tab. 3.
11. §. Upon further Enquiry, I likewise find, That the Pores of the Lignous Body in the Trunks of Herbs, which at first I only supposed, by the help of good Glasses, are very fairly visible: each Fibre being sometimes perforated by 30, 50, 100, or hundreds of Pores. Or what I think is the truest notion of them, That each Fibre, though it seem to the bare eye to be but one, yet is, indeed, a great number of Fibres together; and every Pore, being not meerly a space betwixt the several parts of the Wood, but the Concave of a Fiber. So that if it be asked, what all that Part of a Plant, either Herb or Tree, which is properly called the Woody-Part; what all that is, I suppose, That it is nothing else but a Cluster of innumerable and most extraordinary small Vessels or Concave Fibers: Tab. 3. f. 6. as in a Slice of the Trunk of Burdock is apparent.
12. §. Next the Insertions of the Cortical Body, which in the Trunk of a Tree saw’d athwart, are plainly discerned as they run from the Circumference toward the Center; the whole Body of the Tree being visibly compounded of two distinct Substances, that of the several Rings, and that of the Insertions, running cross; shewing that in some resemblance in a Plain, Tab. 3. f. 5. & 8. which the Lines of Latitude and of the Meridian do in a Globe. The entrance of the Insertions into the Wood, is also, upon striping off the Barque, very apparent; as in the same Fig. 8.
13. §. These Insertions are likewise very conspicuous in Sawing of Trees length-ways into Boards, and those plain’d, and wrought into Leaves for Tables, Wainscot, Trenchers, and the like. In all which, as in course Trenchers made of Beech, and Tables of Oak, there are many parts which have a greater smoothness than the rest; Tab. 3. f. 2. & Tab. 4. f. 1. and are so many inserted Pieces of the Cortical Body; which being by those of the Lignous, frequently intercepted, seem to be discontinuous, although in the Trunk they are really extended, in continued Plates, throughout its Breadth.
14. §. These Insertions, although as is said, of a quite distinct substance from the Lignous Body, and so no where truly incorporated with it, yet being they are in all parts, the one as the Warp, the other as the Woof, mutually braced and interwoven together, they thus constitute one strong and firmly coherent Body; Tab. 4. f. 1. as the Timber of any Tree.
15. §. As the Pores or Vessels are greater or less, so are the Insertions also: To the bare eye usually the greater only are discernable: But through an indifferent Microscope there are others also, much more both numerous and small, distinctly apparent, Tab. 3. f. 7. as in a transverse piece of Oak.
16. §. In none of all the Pores can we observe any thing which may have the true nature and use of Valves, which is, Easily to admit that, to which they will by no means allow a regress. And their nonexistence is enough evident, from what in the first Chapter C. 1. §. 42. we have said of the Lobes of the Seed: in whose Seminal Root, were there any Valves, it could not be, that by a contrary Course of the Sap, they should ever grow; which yet, where-ever they turn into Dissimilar Leaves, they do. Or if we consider the growth of the Root, which oftentimes is upward and downward both at once. And being cut transversely, will bleed, both the same ways, with equal freedom.
17. §. The Insertions here in the Trunk give us likewise a sight of the position of their Pores. For in a plained piece of Oak, as in Wainscot, Tables, &c. besides the larger Pores of the Lignous Body, which run by the length of the Trunk; Tab. 3. f. 2. the Tract likewise of those of the Insertions may be observed to be made by the breadth, and so directly cross. Nor are they continuous as those of the Lignous Body, but very short, as those both of the Cortical Body and Pith, with which the Insertions, as to their substance, are congenerous. Yet they all stand so together, as to be plainly ranked in even Lines or Rows throughout the breadth of the Trunk: As the Tract of those Pores appears to the naked Eye, see in Tab. 3. Fig. 9. The Pores themselves may be seen in the Root of a Vine described and figured in the Second Book, as it appears through a good Microscope. Tab. 17.
18. §. The Pores of the Pith likewise being larger here in the Trunk, are better observable than in the Root: the width whereof, in comparison with their Sides so exquisitely thin, may by an Hony-Comb be grosly exemplified; and is that also which the vast disproportion betwixt the Bulk and Weight of a dry Pith doth enough declare. In the Trunks of some Plants, they are so ample and transparent, that in cutting both by the length and breadth of the Pith, some of them through the transparency of the Skins by which they are bounded, or of which they consist, would seem to be considerably extended by the length of the Pith; but are really discontinuous and short, and as ’tis said, somewhat answerable to the Cells of an Hony-Comb. This is the nearest we can come to them, by the bare Eye without the assistance of a good Microscope. Mr. Hook sheweth in his Micrography, That the Pores of the Pith, particularly of Elder-Pith, so far as they are visible, are all alike discontinuous; and that the Pith is nothing else but (as he calls them) an heap of Bubbles. Although, in regard they are not fluid, but fixed Parts, I shall choose rather to call them, Bladders. As they appear through a good Glass, in a piece of Burdock, See in Tab. 3. Tab. 3. f. 6. But a more particular Description of the Sizes, Figures, and admirable Textures hereof, I have given in several places in the following Books.
19. §. Besides what this Observation informs us of here, it farther confirms what in the Second Chapter C. 2. §. 3, 16, 17. we have said of the Original of the Pith and Cortical Body, and of the sameness of both their natures with the Parenchyma of the Seed: which is nothing else but a Mass of Bladders; C. 1. §. 18. & Tab. 1. f. 9. as in the First Chapter hath been said.
20. §. In the Piths of many Plants, the greater Pores or Bladders have some of them lesser ones within them, and some of them are divided with cross Membranes: And betwixt their several sides, have, I think, other smaller Bladders visibly interjected. However, that they are all permeable, is most certain. They stand together not confusedly, but in even Ranks or Trains; as those of the Insertions by the breadth, so these by the length of the Trunk. And thus far there is a general corresponding betwixt the parts of the Root and Trunk. Yet are there some considerable Disparities betwixt them; wherein, and how they come to pass, and to what especial Use and End, shall next be said.
An Account of the Growth of the Trunk. 21. §. WE SAY then, that the Sap being in the Root by Filtrations, Fermentations (and in what Roots needful, perhaps by Circulation also) duly prepar’d; the prime part thereof passing through the intermediate Coarcture, in due moderation and purity is entertain’d at last into the Trunk. And the Sap of the Trunk being purer and more volatile, and so it self apt to ascend; the motion of the Trunk likewise will be more noble, receiving a disposition and tendency to ascend therewith. And what by the Sap the Trunk is in part dipos’d to, by the respective position and quantity of its Parts it is effectually enabled. For whereas in the Root the Lignous Body being in proportion with the Cortical, but little, and all lying close within its Center; it must therefore needs be under its controul: on the contrary, being here comparatively of greater quantity, and also more dilated, and having divers of its Branches standing more abroad towards the Circumference, as both in the Leaves and Body of the young Trunk and Plume, is seen; it will in its own magnetical tendency to ascend, reduce the Cortical Body to a compliance with it.
22. §. And the Trunk thus standing from under the restraint of the Ground in the open Air, the disposition of its Parts, originally different from that of the Parts in the Root, will not only be continued, but improved. For by the force and pressure of the Sap in its collateral Motion, the Lignous Body will now more freely and farther be dilated. And this being dilated, the Cortical Body also, must needs be inserted; and is therefore in proportion always, more or less, smaller here in the Trunk, than in the Root. And as the Cortical Body lessens, so the Pith will be enlarged, and by the same proportion is here greater. And the Pith being enlarged it self, its Pores (the Lignous Body, upon its dilatation, as it were tentering and stretching out all their sides) must needs likewise be enlarged with it; and accordingly, are ever greater in the Pith of the Trunk, than of the Root. And the dilatation of the Lignous Body still continued, it follows, that whereas the Pith descendent in the Root, is not only in proportion less and less, but also in the smaller extremities thereof, and sometimes higher, altogether absent: Contrariwise, in the Trunk, it is not only continued to its top and smallest Twigs, but also there, in proportion, equally ample with what it is in any other inferiour part.
23. §. But although the openness of the Aer permitting, be always alike; yet the Energy of the Sap effecting, being different; as therefore that doth, the dilatation of the Trunk, will also vary. If that be less, so is this; as in the Trunks of most Trees: If that be greater, so this; as in Herbs is common; the Lignous Body being usually so far dilated, that the utmost Shootings thereof may easily be seen to jut out, and adjoyn to the Skin. And if the Sap be still of greater energy, it so far dilates the Lignous Body, as not only to amplifie the Pith and all its Pores; but also so far to stretch them out, as to make them tear. Whereupon either running again into the Cortical Body, or shrinking up towards it, the Trunk thus sometimes becomes an hollow Stalk, the Pith being wholly, or in part voided. But generally it keeps entire; and where it doth, the same proportion and respect to the Lignous and Cortical Bodies, as is said. The Consequences of all which will be, the Strength of the Trunk, the Security and Plenty of the Sap, its Fermentation will be quicker, its Distribution more effectual, and its Advancement more sufficient.
24. §. First, the Erect Growth and Strength of the Trunk; this being, by the position of its several Parts, effected: for besides the slendering of the Trunk still towards the top, the Circumferential position of the Lignous Body, likewise is, and that eminently, hereunto subservient. So that as the Lignous Body, in the smaller parts, of the Root standing Central, we may thence conceive and see their pliableness to any oblique motion; so here, on the contrary, the Lignous Body standing wide, it thus becomes the Strength of the Trunk, and most advantageous to its Perpendicular Growth. We see the same Design in Bones and Feathers: The strongest Bones, as those in the Legs, are hollow. Now should we suppose the same Bone, to be contracted into a Solid; although now it would be no heavier, and in that respect, as apt for motion; yet would it have far less strength, than as its Parts are dilated to a Circumferential posture. And so for Quills, which, for the same Reasons, in subserviency to flying, as they are exceeding light; So, in comparison with the thinness of their Sides, they are very strong, and much less apt to bend, than if contracted into a Solid Cylinder. We see it not only in Nature, but Art. For hence it is, that Joyners and Carpenters unite and set together their Timber-pieces and several Works oftentimes with double Joynts; which, although they are no thicker, than a single one might be made; yet standing at a distance, have a greater strength than That could have. And the same Architecture, will have the same use, in the Trunks of Plants; in most whereof ’tis very apparent; as for instance, in Corn. For Nature designing its Sap a great Ascent; for its higher maturity, hath given it a tall Trunk: But to prevent its ravenous despoiling either of the Ear, or Soyl; although it be tall, yet are its sides but thin: And because again, it should grow not only tall and thriftily, but for avoiding propping up, strongly too; therefore, the same proportion as its heigth bears, to the thinness of its sides, doth the greatness of its Circumference also; being so far dilated as to parallel a Quil it self.
25. §. Besides the position of the Lignous Body within the compass of a Ring, there are some Shootings thereof, often standing beyond the Circumference of the said Ring, making sometimes a triangular, oftner a quadrangular Body of the Trunk. To the end, that the Ring, being but thin, and not self-sufficient, these, like Splinters to Bones, might add strength and stability to it.
26. §. Next, the security and plenty of the Sap. For should the Lignous Body, as it doth in the smaller Parts of the Root, stand Central here also, and so the Cortical wholly surround it: the greater part of the Sap would thus be more immediately expos’d to the Sun and Aer; and being lodged in a laxe Body, by them continually be prey’d upon, and as fast as supplied to the Trunk, be exhausted. Whereas, the Pith standing in the Center, the Sap therein being not only most remote from the Aer and Sun, but by the Barque, and especially the Wood, being also surrounded and doubly immur’d, will very securely and copiously be convey’d to all the Collateral Parts, and (as shall be said how) the top of the Trunk.
27. §. And the Sap by the amplitude, and great porosity of the Pith, being herein more copious, its Fermentation also will be quicker; which we see in all Liquors, by standing in a greater quantity together, proceeds more kindly: And being tun’d up within the Wood, is at the same time not only secur’d from loss, but all extream mutations; the Day being thus, not too hot; nor the Night, too cold for it.
28. §. And the Fermentation hereof being quicker, its motion also will be stronger, and its Distribution more effectual, not only to the dilatation of the Trunk, but likewise the shooting out of the Branches. Whence it is, that in the Bodies of Trees, the Barque of it self, though it be Sappy, and many Fibres of the Lignous Body mixed with it, yet seldom sendeth forth any; and that in Herbs, those with the least Pith (other advantages not supplying this defect) have the fewest or smallest Branches, or other collateral Growths: and that Corn, which hath no Pith, hath neither any Branches.
29. §. Lastly, the Advancement of the Sap will hence also be more ready and sufficient. For the understanding where, and how, we suppose, That in all Trunks whatsoever there are two Parts joyntly hereunto subservient. In some, the Lignous Body and the Cortical, as in older Trunks; the Pith being either excluded, or dried: But in most, principally, the Lignous Body and Pith; as in most Annual Growths of Trees; but especially Herbs, where the Cortical Body is usually much and often wholly Inserted.
30. §. Of the Lignous Body it is so apparent by its Pores, or rather by its Vessels, that we need no farther Evidence. For to what end are Vessels, but for the conveyance of Liquor? And is that also, which upon cutting the young Branch of a Sappy Tree or Herb, by an accurate and steady view may be observed. But when I say the Vessels of the Lignous Body, I mean principally them of the younger shootings, both those which make the new Ring, and those which are mixed with the Cortical Body in the Barque: that which ascendeth by the Pores or Vessels of the Wood, being probably, because in less quantity, more in form of a Vapour, than a Liquor. Yet that which drenching into the sides of its Pores, is with all thereunto sufficient Aliment; as we see Orpine, Onions, &c. only standing in a moyster Aer will often grow. And being likewise in part supplied by the Insertions from the younger Shoots: But especially because as it is but little, so (considered as Aliment) it serveth only for the growth of the Wood, and no more; whereas, the more copious Aliment ascendent by the younger Shoots, subserves not only their own growth, but the generation of others; and is besides with that in the Cortical Body the Fountain of Perspirations, which we know even in Animals are much more abundant than the Nutritive Parts; and doubtless in a Vegetable are still much more.
31. §. But these Pores, although they are a free and open way to the ascending Sap; yet that meer Pores or Vessels should be able of themselves to advance the Sap with that speed, strength and plenty, and to that height, as is necessary, cannot probably be supposed. It follows then, that herein we must grant the Pith a joynt service. And why else is the Pith in all Primitive Growths the most Sappy part, why hath it so great a stock of Sap, if not, after due maturation within it self, still to be disbursed into the Fibres of the Lignous Body? Why are the Annual Growths of all both Herbs and Trees, with great Piths, the quickest and the longest? But how are the Pores or Bladders of the Pith permeable? That they are so, both from their being capable of a repletion with Sap, and of being again wholly emptied of it, and again, instead thereof fill’d with Aer, is as certain as that they are Pores. That they are permeable, by the breadth, appears from the dilatation of the Lignous Body, and from the production of Branches, as hath been, and shall hereafter be said. And how else is there a Communion betwixt This and the Cortical Body? That they are so also, by the length, is probable, because by the best Microscope we cannot yet observe, that they are visibly more open by the breadth, than by the length. And withall are ranked by the length, as those of the Insertions by the breadth of the Trunk. But if you set a piece of dry Elder-Pith in some tinged Liquor, why then doth it not penetrate the Pores, so as to ascend through the Body of the Pith? The plain reason is, because they are all fill’d with Aer. Whereas the Pith in a Vegetating Plant, as its Parts or Bladders are still generated, they are at the same time also fill’d with Sap; which, as ’tis gradually spent, is still repaired by more succeeding, and so the Aer still kept out; as in all Primitive Growths, and the Pith of Elder it self: Yet the same Pith, by reason of the following Winter, wanting a more copious and quick supply of Sap, thus once become, ever after keeps dry. And since in the aforesaid Trial the Liquor only ascends by the sides of the Pith, that is of its broken Bladder, we should thence by the same reason conclude that they are not penetrable by the breadth neither, and so no way; and then it need not be ask’d what would follow. But certainly the Sap in the Bladders of the Pith is discharged and repaired every moment, as by its shriv’ling up, upon cutting the Plant, is evident.
32. §. We suppose then, that as the Sap ascendeth into the Trunk by the Lignous Body, so partly also by the Pith. For a piece of Cotton with one end immers’d in some tinged Liquor, and with the other erect above, though it will not imbibe the Liquor so far as to over-run at the top, yet so as to advance towards it, it will. So here, the Pith, being a porous and spongy Body, and in its Vegetating state, its Pores or Bladders being also permeable, as a curious Filtre of Natures own contrivance, it thus advanceth, or as people use to say, sucks up the Sap. Yet as it is seen of the Liquor in the Cotton; so likewise are we to suppose it of the Sap in the Pith; that though it riseth up for some way, yet is their some term, beyond which it riseth not, and towards which the motion of the ascending Sap is more and more broken, weak and slow, and so the quantity thereof less and less. But because the Sap moveth not only by the length, but breadth of the Pith; at the same time therefore as it partly ascendeth by the Pith, it is likewise in part pressed into the Lignous Body or into its Pores. And since the motion of the Sap by the breadth of the Pith not being far continued, and but collateral, is more prone and easie, than the perpendicular, or by its length; it therefore follows, that the collateral motion of the Sap, at such a height or part of the Pith, will be equally strong with the perpendicular at another part, though somewhat beneath it; and that where the perpendicular is more broken and weak, the collateral will be less; and consequently where the perpendicular tendency of the Sap hath its term, the collateral tendency thereof, and so its pressure into the Pores or Vessels of the Lignous Body, will still continue. Through which, in that they are small, and so their sides almost contiguous, the Sap as fast as pressed into them will easily run up; as in very small Glasse Pipes, or betwixt the two halves of a Stick first slit, and then tyed somewhat loosely together, may also any Liquor be observed to do. By which Advantage the facility and strength of that ascent will be continued higher in the said Vessels, than in the Pith. Yet since this also, as well as that in the Pith will have its term; the Sap, although got thus far, would at last be stagnant, or at least its ascent be very sparing, slow and feeble, if not some way or other re-inforced. Wherefore, as the Sap moving by the breadth of the Pith, presseth thence into the Vessels of the Lignous Body; so having well fill’d these, is in part by the same Collateral motion disbursed back, into a yet higher Region of the Pith. By which partly, and partly, by that portion of the Sap, which in its perpendicular ascent was before lodged therein; ’tis thus here, as in any inferiour place equally replenished. Whereupon the force and vigour of the perpendicular motion of the Sap herein, will likewise be renew’d; and so its Collateral motion also, and so its pressure into the Vessels of the Lignous Body, and consequently its ascent therein: and so by a pressure, from these into the Pith, and from the Pith into these, reciprocally carried on; a most ready and copious ascent of the Sap will be continued, from the bottom to the top, though of the highest Tree.