Chapter II: Part 2

The Pores of the _Pith_, as those of the _Cortical Body_, are extended both by the breadth and length of the _Root_, much alike; yet are they more or less of a greater size than those of the _Cortical Body_.

The Proportions of the _Pith_, are various; in Trees, but small; in Plants generally, very fair; in some making by far the greatest part of the _Root_; as in a _Turnep_: By reason of the wide circumference whereof, and so the finer Concoction and Assimilation of its Sap; that part which in most old Trunks is a dry and harsh _Pith_, here proves a tender pleasant meat. The parts of a _Turnep_ in the travers cut see in _Fig. 8_.

In the Roots of very many Plants, as _Turneps_, _Carrots_, &c. the _Lignous Body_, besides its main utmost Ring, hath divers of its osculated Fibres dispersed throughout the Body of the _Pith_; sometimes all alike, and sometimes more especially in, or near, its Center; which Fibres, as they run towards the top of the _Root_, still declining the Center, at last collaterally strike into its Circumference; either all of them, or some few, keeping the Center still; of these principally the _Lignous Body_ of the Trunk is often originated.

These Fibres, although they are so exceeding slender, yet in some _Roots_, as in that of _Flower-de-liz_, they are visibly concave, each of them, in their several Cavities also embosoming a very small _Pith_; the sight whereof, the Root being cut traverse, and laid in a Window for a day or two to dry, may without Glasses be obtained. And this is the general account of the _Root_; the declaration of the manner of its growth, with the use and service of its several parts, we shall next endeavour.

We say then, that the _Radicle_ being impregnate, and shot into the Moulds, the contiguous moisture, by the _Cortical Body_, being a Body laxe and Spongy, is easily admitted: Yet not all indiscriminately, but that which is more adapt to pass through the surrounding Cuticle. Which transient Sap, though it thus becomes fine, yet is not simple; but a mixture of Particles, both in respect of those originally in the Root, and amongst themselves, somewhat heterogeneous. And being lodg’d in the _Cortical Body_ moderately laxe, and of a Circular form; the effect will be an easie Fermentation. The _Sap_ fermenting, a separation of Parts will follow; some whereof will be impacted to the Circumference of the _Cortical Body_, whence the Cuticle becomes a Skin; as we see in the growing of the Coats of Cheeses, of the Skin over divers Liquors, and the like. Whereupon the _Sap_ passing into the _Cortical Body_, through this, as through a _Manica Hippocratis_, is still more finely filtred. With which _Sap_, the _Cortical Body_ being dilated as far as its _Tone_, without a solution of Continuity will bear; and the supply of the _Sap_ still renew’d; and the purest part, as most apt and ready, recedes, with its due Tinctures, from the said _Cortical Body_, to the _Lignous_. Which _Lignous Body_ likewise super-inducing its own proper Tinctures into the said _Sap_; ’tis now to its highest preparation wrought up, and becomes (as they speak of that of an Animal) the Vegetative _Ros_ or _Cambium_: the noblest part whereof is at last coagulated in, and assimilated to the like substance with the said _Lignous Body_. The remainder, though not united to it, yet tinctur’d therein, thus retreats, that is, by the continual appulse of the _Sap_, is in part carried off into the _Cortical Body_ back again, the _Sap_ whereof it now tinctures into good Aliment: So that whereas before the _Cortical Body_ was only relaxed in its Parts, and so dilated; ’tis now increas’d in real quantity or number of parts, and so is truly nourish’d. And the _Cortical Body_ being saturate with so much of this Vital _Sap_ as serves it self; and the second Remainders discharged thence to the Skin; this also is nourish’d and augmented therewith. So that as in an _Animal Body_ there is no instauration or growth of Parts made by the Bloud only, but the _Nervous Liquor_ is also thereunto assistant; so is it here: the _Sap_ prepared in the _Cortical Body_, is as the Arterious; and that part thereof prepared by the _Lignous_, is as the _Nervous Liquor_; which partly becoming Nutriment to it self, and partly being discharged back into the _Cortical Body_, and diffusing its Tincture through the _Sap_ there, that to the said _Cortical Body_ and _Skin_, becomes also true Nutriment, and so they all now grow.

In which growth, a proportion in length and breadth is requisite: which being rated by the benefit of the Plant, both for firm standing and sufficient Sap, must therefore principally be in length. And because it is thus requisite, therefore by the constitution of one of its Parts, _sc._ the _Lignous Body_, it is also made necessary. For the Pores hereof, in that they are all extended by its length, the _Sap_ also according to the frame and site of the said Pores will principally move; and that way as its _Sap_ moves, the same way will the generation of its Parts also proceed; _sc._ by its length. And the _Lignous Body_ first (that is, by a priority causal) moving in length it self; the _Cortical_ also moves therewith. For that which is nourish’d, is extended; but whatever is extended, is mov’d; that therefore which is nourish’d, is mov’d: The _Lignous Body_ then being first nourish’d, ’tis likewise first mov’d, and so becomes and carries in it the Principle of all Vegetative motion in the _Cortical_; and so they both move in length.

Yet as the _Lignous Body_ is the Principle of Motion in the _Cortical_; so the _Cortical_ is the Moderator of that in the _Lignous_: As in Animal Motions, the Principle is from the Nerves; yet being once given to the Muscle or Limb, and that moving proportionably to its structure, the Nerves also are carried in the same motion with it. We suppose therefore, that as the principal motion of the _Lignous Body_ is in length, so is its proper tendency also to ascend: But being much exceeded both in Compass and Quantity by the _Cortical_ as in the smaller parts of the _Root_ it is; it must needs therefore be over-born and governed by it; and so, though not lose its motion, yet make it that way wherein the _Cortical Body_ may be more obedient to it; which will be by descent: Yet both of them being sufficiently pliable, they are thus capable, where the Soyl I may oppose a direct descent, there to divert any way where it is more penetrable, and so to descend obliquely. For the same reason it may also be, that though you set a _Bean_ with the _Radicle_ upward; yet the _Radicle_, as it shoots, declining also gradually, is thus arch’d in form of an Hook, and so at last descends. For every declination from a perpendicular Line, is a mixed motion betwixt Ascent and Descent; as that of the _Radicle_ also is, and so seeming to be dependent upon the two contrary Tendencies of the _Lignous_ and _Cortical Bodies_. What may be the cause of those Tendencies (being most probably external, and perhaps something of a _Magnetisme_) is besides my Task here to enquire.

Now although the _Lignous Body_, by the position and shape of its Pores, principally groweth in length; yet will it in some degree likewise in breadth: For it cannot be supposed that the purest _Sap_ is all received into the said Pores; but that part thereof likewise, staying about its _Superficial parts_, is there tinctur’d and agglutinated to them. And because these Pores are prolonged by its length; therefore is it much more laxe and easily divisible that way; as in slitting a Stick, or cleaving of Timber, and in cutting and hewing them athwart is also seen. Whence it comes to pass, that in shooting from the Center towards the Circumference, and there finding more room, its said original Laxity doth easily in divers places now become greater, and at length in open Partments plainly visible. Betwixt which Partments, the _cortical Body_, being bound in on the one hand, by the surrounding Skin and Moulds, and pressed upon by the _Lignous_ on the other, must needs insert it self, and so move contrary to it, from the Circumference towards the Center: where the said contrary motions continued as begun, they at last meet, unite, and either make or augment the _Pith_. And thus the _Root_ is fram’d, and the Skin, the _cortical_ and _Lignous Bodies_, so as is said, hereunto concurrent. We shall next shew the use of the two other Parts, _sc_. the _Insertment_ and _Pith_; and first of the _Pith_.

One true use of the _Pith_ is for the better Advancement of the _Sap_, whereof we shall speak in the next Chapter. The use we here observe is for the quicker and higher Fermentation of the _Sap_: For although the Fermentation made in the _Cortical Body_ was well subservient to the first Vegetations, yet those more perfect ones in the _Trunk_ which after follow, require a Body more adapted to it, and that is the _Pith_; which is so necessary, as not to be only common to, but considerably large in the _Roots_ of most Plants; if not in their inferiour parts, yet at their tops. Where though either deriv’d or amplify’d from the _Cortical Body_, yet being by its Insertions only, we may therefore suppose, as those, so this, to be more finely constituted. And being also from its co-arctation, while inserted, now free; all its Pores, upon the supply of the _Sap_, will more or less be amplified: Upon which accounts, the _Sap_ thereinto received, will be more pure, and its fermentation therein more active. And as the _Pith_ is superiour to the _Cortical Body_ by its Constitution, so by its Place. For as it thus stands central, it hath the _Lignous Body_ surrounding it. Now as the Skin is the Fence of the _Cortical Body_, and that of the _Lignous_; so is the _Lignous_ again a far more preheminent one unto the _Pith_; the _Sap_ being here a brisk Liquor, tunn’d up as in a wooden Cask.

And as the _Pith_ subserves the higher Fermentation of the _Sap_; so do the Insertions its purer Distribution; that separation which the parts of the _Sap_, by being fermented in the _Pith_, were dispos’d for; being, upon its entrance into the Insertions, now made: So that as the Skin is a Filtre to the _Cortical Body_, so are the Insertions a more preheminent one to the _Lignous_; and as they subserve the purer, so the freer and sufficient distribution of the _Sap_: For the _Root_ enlarging, and so the _Lignous Body_ growing thicker, although the _Cortical_ and the _Pith_ might supply _Sap_ sufficient to the nutrition of its Parts next adjacent to them; yet those more inward, must needs be scanted of their _Aliment_; and so, if not quite starv’d, yet be uncapable of equal growth: Whereas the _Lignous Body_ being through its whole breadth frequently disparted, and the _Cortical Body_ inserted through it; the _Sap_ by those Insertions, as the Blood by the disseminations of the _Arteries_, is freely and sufficiently convey’d to its intimate Parts, even those which from either the _cortical Body_ or the _Pith_ are most remote. Lastly, as the consequent hereof, they are thus assistant to the Latitudinal growth of the _Root_; as the _Lignous Body_ to its growth in length; so these Insertions of the _Cortical_, to its better growth in breadth.

Having thus seen the solitary uses of the Several Parts of the _Root_, we shall lastly propound our Conjectures of that Design whereto they are all together concurrent, and that is the Circulation of the _Sap_: For the _Sap_ moving through the _cortical Body_, towards the _Pith_, through the Insertions thereinto, obtains a pass: Which passage, the superiour Insertions will not favour; because the _Pith_ standing in the same height with them, is there large, the fermenting and course of the _Sap_ quick, and so its opposition strong. But through the inferiour it will much more easily enter; because there, through the smalness of the _Pith_, the opposition is little, and through the shortness of the Insertions, the way more open. So that though the _Sap_ may meet with some opposition even here, yet here meeting with the least, here it will bestow it self (feeding the _Lignous Body_ in its passage) into the _Pith_. Into which fresh _Sap_ still entring, this, yet but crude, will subside: that first received and so become a Liquor higher wrought, will more easily mount upwards; and moving in the _Pith_, as in the _Arteria magna_, in equal altitude with the more superiour Insertions; the most volatile parts of all will still continue their direct ascent towards the _Trunk_. But those of a middle nature, and, as not apt to ascend, so being lighter than those beneath them, not to descend neither; they will tend from the _Pith_ towards the Insertions in a motion betwixt both; through which Insertions (feeding the _Lignous Body_ in its passage) it is, by the next subsequent _Sap_, discharged off into the _cortical Body_, as into the _Vena cava_, back again. Wherein, being still pursu’d by fresh _Sap_ from the Center, and more occurring from the Circumference, towards the inferiour Insertions it thus descends; through which, together with part of the _Sap_ afresh imbib’d from the Mould, it re-enters the _Pith_. From whence, into the _Cortical Body_, and from thence into the _Pith_, the cruder part thereof reciprocally is disburs’d; while the most Volatile, not needing the help of a Circulation, more directly ascendeth towards the _Trunk_.

CHAP. III.

_Of the Trunk._

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.

CHAP. IV.

_Of the Germen, Branch, and Leaf._

The Parts of the _Germen_ and _Branch_, are the same with those of the _Trunk_; the same _Skin_, _Cortical_ and _Lignous Bodies_, _Insertment_ and _Pith_, hereinto propagated, and distinctly observable herein.

For upon Enquiry into the Original of a _Branch_ or _Germen_, it appears, That it is not from the _Superficies_ of the _Trunk_, but so deep, as to take with the _Cortical_, the _Lignous Body_ into it self; and that not only from its Circumference, but (so as to take the _Pith_ in also) from its _Inner_ or _Central parts_. Divers whereof may commonly be seen to shoot out into the _Pith_; from which _Shoots_ the surrounding and more superiour _Germens_ are originated; in like manner as the _Lignous Body_ of the _Trunk_ is sometimes principally from those Fibrous _Shoots_ which run along the _Pith_ in the _Root_.

The manner wherein usually the _Germen_ and _Branch_ are fram’d, is briefly thus: The _Sap_ (as is said, _Chap. 3._) mounting in the _Trunk_, will not only by its length, but by its breadth also, through the _Insertions_ partly move. Yet, its Particles being not all alike qualified, in different degrees: Some are more gross and sluggish; of which we have the formation of a Circle of Wood only; or of an Annual Ring: Others are more brisk; and by these we have the _Germen_ propagated. For by the vigour of their own motion from the Center, they impress an equal tendency on some of the inner parts of the _Lignous Body_ next adjacent to the _Pith_, to move with them. And since the _Lignous Body_ is not entire, but frequently disparted; through these dispartments, the said interiour Parts, upon their Nutrition, actually shoot; not only towards the Circumference, so as to make part of a Ring, but even beyond it, in order to the production of a _Germen_. And the _Lignous Body_ thus moving, and carrying the _Cortical_ along with it; they both make a force upon the _Skin_: Yet their motion being most even and gradual, that force is such likewise; not to cause the least breach of its parts, but gently to carry it on with themselves; and so partly by the extension of its already existent parts, as of those of Gold in drawing of Guilded Wyer; and partly by the accretion of new ones, as in the enlarging of a Bubble above the Surface of the Water, it is extended with them to their utmost growth. In which growth, the _Germen_ being prolonged, and so displaying its several parts, as when a _Prospective_ or _Telescope_ is drawn out, thus becomes a _Branch_.

The same way as the propagation of the Parts of a _Germen_ is contriv’d is its due nutrition also: For being originated from the inner part of the _Lignous Body_, ’tis nourished with the best fermented _Sap_ in the _Trunk_, _sc._ that next adjacent to it in the _Pith_. Besides, since all its Parts, upon their shooting forth, divaricate from their perpendicular, to a cross Line, as these and the other grow and thrive together, bind and throng each other into a Knot; through which Knot the _Sap_ being strain’d, ’tis thus in due moderation & purity delivered up into the Branch.

And for Knots, they are so necessary, as to be seen not only where collateral Branches put forth; but in such Plants also as shoot up in one single _Trunk_; as in _Corn_; wherein, as they make for the strength of the _Trunk_; so by so many percolations as they are Knots, for the transmission of the _Sap_ more and more refined towards the Ear. So that the two general uses of Knots are for firmer standing, and finer growth.

Lastly, as the due Formation and Nutrition of the _Germen_ are provided for, so is its security also; which both in its position upon the _Trunk_, and that of its Parts among themselves may be observed. The position of its Parts shall be considered in speaking of the Leaf. As to its standing in the _trunk_, ’tis alwayes betwixt the _trunk_ or _Elder Branch_, and the _Basis_ of the Stalk of the _Leaf_; whereby it is not only guarded from the Injuries of any contingent Violence, but also from the more piercing assaults of the Cold, so long till in time ’tis grown, as larger, so more hardy. The manner and uses of the position of every _Germen_, considered as after it becomes a _Branch_, hath already been by the Ingenious Mr. _Sharrock_ very well observed; to whom I refer.

Upon the prolongation of the _Germen_ into a _Branch_, its _Leaves_ are thus display’d. The Parts whereof are substantially the same with those of a _Branch_: For the Skin of the Leaf is only the ampliation of that of the _Branch_; being partly by the accretion of new, & partly the extention of its already existent parts (dilated as in making of _Leaf-Gold_) into its present breadth. The Fibres or Nerves dispersed through the Leaf, are only the Ramifications of the _Branch_’s Wood, or _Lignous Body_. The _Parenchyma_ of the Leaf which lies betwixt the Nerves, and as in Gentlewomens Needle-works, fills all up, is nothing else but the continuations of the _Cortical Body_, or inner part of the _Barque_ from the _Branch_ into it self, as in most Plants with a fat Leaf, may easily be seen.

The Fibres of the _Leaf_ neither shoot out of the _Branch_ nor _Trunk_, nor stand in the _Stalk_, in an even Line; but alwayes in either an Angular or Circular posture, and usually making either a Triangle, or a Semi-Circle, or Cord of a Circle; as in _Cycory_, _Endive_, _Cabbage_, &c. may be observed: And if the Leaf have but one main Nerve, that also is postur’d in a Circular or Lunar Figure; as in _Mint_ and others. The usual number of these Nerves or Fibres is 3, 5, or 7. See the _Figures_ from 20, to 29.

The reason of the said Positions of the Fibres in the _Stalk_ of the _Leaf_, is for its more erect growth, and greater strength; which, were the position of the said Fibres in an even Line, and so the Stalk it self, as well as the Leaf flat, must needs have been defective; as from what we have said of the Circumferential posture of the _Lignous Body_ in the _Trunk_, we may better conceive.

As likewise for the security of its _Sap_: For by this means it is, that the several Fibres, and especially the main or middle Fibre of the Leaf, together with a considerable part of the _Cortical Body_, are so disposed of, as to jut out, not from its upper, but its back, or nether plain. Whence the whole Leaf, reclining backward, becomes a Canopy to them, defending them from those Injuries which from colder Blasts, or an hotter Sun, they might otherwise sustain. So that by a mutual benefit, as these give suck to all the Leaf, so that again protection to these.