Having 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.
That which without dissection shews it self, is the Coarcture: I cannot say of the Root, nor of the Trunk; but what I chuse 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.
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.
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 Seed; and is only the increase and augmentation thereof. The Skin, this Cortical Body properly so call’d, and (for the most part) some Fibers of the Lignous mixed herewith, all together make the Barque.
Next, the Lignous Body, which, whether it be visibly divided into many softer Fibres, as in Fennel, and most Plants; 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 Inner Body distributed in the Lobes and Plume thereof.
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.
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 visible in so many Rings, as is commonly known: For several young Fibres of the Lignous Body, as in the Root, so here, shooting into 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.
From these Annual younger Fibres 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 Fibers annually shoot into, and so communicate with it.
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 run one into another, but keep, like so many several Vessels, all along distinct; 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.
These greater Pores, though in Wainscot, Tables, and the like, where they have lain long open, they are but meer Vacuities, and so would be thought to contain only Sap in the Tree, and afterwards only Air; yet upon a fresh cut, each of them may be seen fill’d up with a light and spongie Body, which by Glasses, and even by the bare eye, appears to be a perfect Pith; sometimes entire, and sometimes more or less broken.
Besides these, there are a lesser sort; which, by the help of a Microscope, also appear, if not to be fill’d up with a Pith, yet to contain certain light and filmy parts, more or fewer, of a Pithy nature within them.
And these are all the Pores the best Glasses, which, (when upon these Enquiries) we had at hand, would shew us. But the Learned and most Ingenious Naturalist Mr. Hook sheweth us moreover, besides these, a third, and yet smaller sort; the description whereof I find he hath given us amongst his Microscopical Observations. Of these Pores (as a confirmation of what, in the Second Chapter, I have said of the Pores of the Lignous Body in general) he also demonstrates; that they are all continuous and prolonged by the length of the Trunk; as are the greater ones; the Experiment whereof he imparteth to be, by filling up, suppose 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.
Upon farther Enquiry, I likewise find, that the Pores of the Lignous Body in the Trunk of Plants, which at first only supposed, by the help of good Glasses are very fairly visible; each Fibre being 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; every Pore being not meerly a space betwixt the several pores of the Wood, but the Concave of a Fiber: So that if it be asked, what all that part of a Vegetable, either Plant or Tree, which is properly call’d the woody part; what all that is, I suppose, that is nothing else but a Cluster of innumerable and most extraordinary small Vessels or concave Fibres. See Fig. 15.
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, which the Lines of Latitude and of the Meridian do in a Globe. See Fig. 16.
These Insertions are likewise very conspicuous in Sawing of Trees length-wayes 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; and are so many inserted pieces of the Cortical Body; which by reason of those of the Lignous, seem to be discontinuous; although in the Trunk they are extended throughout its Breadth.
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 inter-woven together, they thus constitute one strong and firmly coherent Body.
As the Pores 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. So that, I think, we may observe, that as the grand Pith of the Trunk communicates with, and is augmented by the greater Insertions; so is the Pith of each greater Pore originated from the less; and those (at least) pithy parts in the Midling Pores, from others still less; and suppose, that the least of all are so far intruded into the smallest Pores, as only just to cause a kind of roughness on their concave sides, and no more; to what end shall be said. See Fig. 17.
In none of all these 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 non-existence is enough evident, from what in the first Chapter 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.
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; 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 these Pores appear to the naked Eye, see in Fig. 18. By the best Microscope I have at hand, I can only observe the Ranks of the Pores; not the Pores themselves, saving here and there one; wherefore I have not describ’d them.
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 Honey-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, even to the bare eye would seem to be considerably extended by the length of the said Pith; which once I also thought they were, and that only the rest of them were but short and discontinuous, and as ’tis said, somewhat answerable to the Cells of an Honey-Comb. This was the nearest we could come to them, by conjecture, and the assistance of the best Glasses we then had by us, when upon enquiry into the nature of the Pith: But that Worthy Person newly mentioned Mr. Hooke sheweth us, 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 (to use his own words) but an heap of Bubbles.
Besides what this Observation informs us of here, it farther confirms what in the second Chapter 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. For, upon farther enquiry with better Glasses, I find, that the Parenchyma of the Plume and Radicle, and even of the Lobes themselves, though not so apparently, is nothing else but a Mass of Bubbles.
In the Piths of many Plants, the greater Pores 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 Pores visibly interjected. However, that they are all permeable, is most certain. They stand together not indeterminately, 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 part 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.
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 dispos’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 tendency to ascend, reduce the Cortical Body to a compliance with it.
And the Trunk thus standing from under the restraint of the Mould 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 alwayes 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, but also there in proportion equally ample with what it is in any other inferiour part.
But although the openness of the Ayr permitting be alwayes 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 is this; as in Plants 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 voyded. 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.
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 part 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 Body, although now it would be no heavier, and in that respect, as apt for motion; yet would it have far less strength, than as it is dilated to a Circumferential posture. And so for Quills, which, for the same Reasons, in subserviency to flight, we see how exceeding light they are, and yet, in comparison with the thinness of their Body, how very strong: 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, as its height is over-proportioned to the thinness of its sides, so is its Circumference also; being so far dilated as to parallel a Quill it self. Besides the position of the Lignous Body within the compass of a Ring, we see 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.
Next, the security and plenty of the Sap. For should the Lignous Body, as it doth in the Root, its smaller parts, 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 ayr; and being lodg’d 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 Ayr and Sun, but by the Barque, and especially the Wood, being also surrounded and doubly immur’d, will very securely and copiously be conveyed to all the Collateral parts, and (as shall be said how) the top of the Trunk.
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 tunn’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.
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 Plants, 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.
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 Plants, where the Cortical Body is usually much and often wholly inserted.
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 Plant, by an accurate and steady view may be observed. But when I say the Pores 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 of the older 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 Ayr 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 it serveth only for the growth of the said Older 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.
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 & 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 in the smaller parts of the Root, where the Pith is often wanting, are the Pores there greater? Why 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 Plants and Trees with great Piths, the quickest and the longest? But how are the Pores 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 Ayr, 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 observ, that they are visibly more open by the breadth, than by the length. And withal 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 Ayr. Whereas the Pith in a Vegetating Plant, as its Parts or Pores are still generated, they are at the same time also fill’d with Sap; which, as ’tis gradually spent, is still repair’d by more succeeding, and so the Ayr 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 Pores, 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 Pores of the Pith is discharged and repaired every moment, as by its shriv’ling up; upon cutting the Plant is evident.
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 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 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 betwixt the two halves of a Stick first slit, and then tied somewhat loosely together, may also any Liquor be observed to do. And the sides of the said Pores being not smooth, but by the intrusion of the smallest insertions made somewhat rough; by that means the higher and more facile ascent of the Sap therein will farther be promoted. By all which Advantages the facility and strength of that ascent will be continued higher in the said Pores 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 yet 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 Pores 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 repleat. 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 Pores 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 Trunk.
An Appendix.
Of Trunk-Roots and Claspers.
The distinct Parts whereof these are constituted, are the same with those of the Trunk, and but the continuation of them.
Trunk-Roots are of two kinds: Of the one, are those that vegetate by a direct descent: The place of their Eruption is sometimes all along the Trunk; as in Mint, &c. Sometimes only at its utmost point, as in the Bramble.
The other sort are such as neither ascend nor descend, but shoot forth at right Angles with the Trunk; which therefore, though as to their Office, they are true Roots, yet as to their Nature, they area Middle thing betwixt a Root and a Trunk.
Claspers, though they are but of one kind, yet their nature is double; not a mean betwixt that of the Root and that of the Trunk, but a compound of both; as in their Circumvolutions, wherein they often mutually ascend and descend, is seen.
The use of these Parts may be observed as the Trunk mounts, or as it trails. In the mounting of the Trunk, they are for support and supply: For support, we see the Claspers of Vines; the Branches whereof being very long, fragile and slender, unless by their Claspers they were mutually contain’d together, they must needs by their own weight, and that of their Fruit, undecently fall, and be also liable to frequent breaking. So that the whole care is divided betwixt the Gardener and Nature; the Gardener with his Ligaments of Leather secures the main Branches; and Nature with these of her own finding, secures the less. Their Conveniency to which end, is seen in their Circumvolutions, a motion not proper to any other Part: As also in their toughness or strength, though much more slender than the Branches whereon they are appendent.
For Supply, we see the Trunk-Roots of Ivy: For mounting very high, and being of a closer Constitution than that of a Vine, the Sap could not be sufficiently supplied to the upper Sprouts, unless these to the Mother-Root were joyntly assistant. Yet serve they for support likewise; whence they shoot out, not as in Cresses, Brook-lime, &c. reciprocally on each side, but commonly all in one; that so they may be fastened at the nearest hand.
In the Trailing of the Trunk, they serve for stabiliment, propagation and shade. For stabiliment, we see the Claspers of Cucumbers: For the Trunk and Branches being long and fragile, the Brushes of the Winds would injuriously hoise them to and fro, to the dammage both of themselves and their tender Fruit, were they not by these Ligaments brought to good Association and Settlement.
As for this end, so for Propagation, we see the Trunk-Roots of Camomile. Whence we have the reason of the common observation, that it grows better by being trod upon: the Mould, where too laxe, being thus made to lie more conveniently about the said Trunk-Roots newly bedded therein; and is that which we see also effected in Rowling of Corn.
For both these ends, we see the Trunk-Roots of Strawberries; as also for shade; for in that we see all Strawberries delight; and by the trailing of the Plant is well obtain’d: So that as we are wont to tangle the Twigs of Trees together to make an Arbour Artificial; the same is here done to make a Natural one; as likewise by the Claspers of Cucumbers: For the Branches of the one by the Linking of their Claspers, and of the other by the Tethering of their Trunk-Roots, being couched together; their tender fruits thus lie under the Umbrage of a Bower made of their own Leaves.
