_Of the Root._
Having examin’d and pursu’d the Degrees of _Vegetation_ in the _Seed_,
we find its two Lobes have here their utmost period; and, that having
conveyed their Seminalities into the _Radicle_ and into the _Plume_;
these therefore as the Root and Trunk of the Plant still survive; Of
these in their order we next proceed to speak; and first, of the _Root_:
whereof, as well as of the _Seed_, we must by Dissection inform our
selves.
In Dissection of a _Root_ then, we shall find it with the _Radicle_, as
the Parts of an old man with those of a _Fœtus_, substantially one. The
first Part occurring is its skin, the Original whereof is from the Seed:
For that extream thin Cuticle which is spred over the Lobes of the Seed,
and from thence over the _Radicle_, upon the shooting of the _Radicle_
into a Root, is co-extended, and becomes its Skin.
The next Part is the _Cortical Body_; the Original whereof likewise is
from the Seed; or the _Parenchyma_, which is there common both to the
Lobes and _Radicle_, being by Vegetation augmented and prolonged into the
_Root_, is here the _Cortical Body_, or that which is sometimes called
the _Barque_.
The Contexture of this _Cortical Body_ may be well illustrated by
that of a _Sponge_, being a Body Porous, Dilative, and Pliable. Its
Pores, as they are innumerable, so extream small. These Pores are not
only susceptive of so much Moisture as to fill, but also to enlarge
themselves, and so to dilate the _Cortical Body_ wherein they are; which
by the shriv’ling in thereof, by being expos’d to the Air, is also seen.
In which dilatation many of its Parts becoming more lax and distant, and
none of them suffering a solution of their continuity; ’tis a Body also
sufficiently pliable; or, a most exquisitely fine-wrought Sponge.
The Extention of these Pores is much alike both by their length and
breadth of the Root; which from the shrinking up of the _Cortical Body_,
in a piece of a cut Root, by the same dimensions, is argu’d.
The proportions of this _Cortical Body_ are various: If thin, ’tis
called a _Barque_; & thought to serve to no other end, than what is
usually ascrib’d to it as a _Barque_; which is a narrow conceit: If a
Bulky Body in comparison with that within it, as in the young Roots of
_Cychory_, _Asparagus_, &c. ’tis here, because the fairest, therefore
taken for the prime Part; which, though, as to Medicinal use, it is;
yet, as to the private use of the Plant, not so. The Colour hereof,
though it be originally white, yet in the continued growth of the Root,
divers Tinctures, as yellow in _Dock_, red in _Bistort_, are thereinto
introduced.
Next within this Part stands the _Lignous Body_; the Original whereof,
as of the two former, is from the Seed; or, the _Seminal Roots_ of both
the Lobes, being united in the _Radicle_, and with its _Parenchyma_
co-extended, is here in the Root the _Lignous Body_.
The Contexture hereof is, in many of its parts, much more close than that
of the _Cortical_; and their Pores very different: For whereas those of
the _Cortical_ are infinitely numerous, these of the _Lignous_ are in
comparison, nothing so. But these, although fewer, yet are they many of
them more open, fair, and visible: as in a very thin Slice cut athwart
the young Root of a Tree, and held up against the Light, is apparent: Yet
not in all equally, in _Coran_-Tree, in _Goosberry_-Tree, _&c._ less; in
_Oak_, _Plums_, and especially _Damascens_, more; in _Elder_, _Vines_,
&c. more conspicuous. And as they are different in number and size,
so also (whereon the numerousness of the Pores of the _Cortical Body_
principally depends) in their shape. For whereas those of the _Cortical
Body_ are extended much alike both by the length and breadth of the
_Root_; these of the _Lignous_ are only by the length; which, especially
in _Vines_ and some other _Roots_, is evident. Of these Pores, ’tis also
observable, that although in all places of the _Root_ they are visible,
yet most fair and open about the _Fibrous Extremities_ of some _Roots_
(and in many _Roots_ higher) where there is no Pith. These Pores, as they
shew in young _Roots_ of Trees, see in _Fig. 6_, & _7_.
This _Lignous Body_ lieth with all its Parts, so far as they are visible,
in a Circle or Ring; yet are there divers extream small Fibres thence
shooting, usually mixed with the _Cortical Body_; and by the somewhat
different colour of the said _Cortical Body_ where they stand, may be
noted these Fibres; the _Cortical Body_ and _Skin_ all together, properly
make the _Barque_.
The proportion betwixt this _Lignous Body_ and the _Cortical_, is
various, as was said; yet in this, constant, _sc._ that in the fibrous,
and smaller Parts of the _Root_, the _Lignous Body_ is not only in
compass, but in quantity the less; running like a slender Wyer or Nerve
through the other surrounding it. They stand both together pyramidally,
which is most common to _Infant-Roots_, but also to many other.
The next Part observable in the _Root_, is the _Insertment_. The
existence hereof, so far as we can yet observe, is sometimes in
the _Radicle_ of the Seed it self; I cannot say alwayes. As to its
substantial nature, we are more certain; that it is the same with that
of the _Parenchyma_ of the _Radicle_; being alwayes at least augmented,
and so, in part, originated from the _Cortical Body_, and so, at second
hand, from the said _Parenchyma_: For in dissecting a _Root_, we find,
that the _Cortical Body_ doth not only environ the _Lignous_, but is also
wedg’d, and in many pieces inserted into it; and that the said inserted
pieces, make not a meer Indenture, but transmit and shoot themselves
quite through as far as the Pith; which in a thin Slice cut athwart the
_Root_ as so many lines drawn from the Circumference towards the Center,
shew themselves. See _Fig. 6_, & _7_.
The Pores of the _Insertment_ are sometimes, at least, extended somewhat
more by the breadth of the _Root_, as about the top of the _Root_ of
_Borage_ may be seen; and are thus different from those of the _Cortical
Body_, which are extended by the length and breadth much alike; and from
those of the _Lignous_, being only by its length.
The number and size of these Insertions are various. In _Hawthorn_, and
some others, and especially _Willows_, they are most extream small; in
_Cherries_ and _Plums_ they are large; and in _Damascens_ especially,
very fairly apparent. In the _Roots_ of small _Plants_ they are generally
more easily discoverable; which may lead to the observation of them in
all.
These Insertions, although they are continuous through both the length
and breadth of the _Root_; yet not so in all Parts, but by the several
shootings of the _Lignous Body_ are frequently intercepted. For of the
_Lignous Body_ it is (here best) observable, That its several shootings,
betwixt which the _Cortical_ is inserted, are not throughout the _Root_
wholly distinct; but that all along being enarch’d, the _Lignous Body_,
both in length and breadth, is thus disposed into Braces or Osculations.
Betwixt these several shootings of the _Lignous Body_ thus osculated,
the _Cortical_ shooting, and being also osculated answerably Brace for
Brace, that which I call the _Insertment_ is fram’d thereof.
These Osculations are so made, that the Pores of the _Lignous Body_, I
think, notwithstanding, seldom run one into another; but, for the most
part, still keep distinct; in the same manner as some of the Nerves,
though they meet, and for some space are associated together, yet ’tis
most probable that none of their Fibres are truly inosculated here, but
only in the Plexures.
These Osculations of the _Lignous Body_, and so the interception of the
Insertions of the _Cortical_, are not to be observ’d by the traverse
cut of the _Root_, but by taking off the _Barque_, or the _Cortical
Body_. In the Roots of Trees, they are generally obscure; but in Plants,
often more distinctly apparent; and especially in a _Turnep_: the
appearance whereof, the _Cortical Body_ being stripp’d off, is as a piece
of close-wrought Network, fill’d up with the Insertions of the said
_Cortical Body_. See _Fig. 8_.
The next and last distinct Part of the _Root_ is the _Pith_. The
substantial nature thereof, is, as was said of the _Insertment_, the
same likewise with that of the _Parenchyma_ of the Seed. And according
to the best observation we have yet made, ’tis sometimes existent in its
_Radicle_; in which, the two main Branches of the Lobes both meeting, and
being osculated together, are thus dispos’d into one round Trunk, and so
environing part of the _Parenchyma_, make thereof a _Pith_; as in either
the _Radicle_, or the young _Root_ of the great _Bean_ or _Lupine_, may,
I think, be well seen.
But many times the Original hereof is immediately from the _Cortical
Body_. For in dissection of divers _Roots_ both of Trees and Plants, as
of _Barberry_ or _Mallows_, it is observable, that the _Cortical Body_
and _Pith_ are both of them participant of the same Colour; in the
_Barberry_ both of them tinged yellow, and in _Mallows_ green. In cutting
the smaller Parts of the Roots of many Plants, as of _Borage_, _Mallows_,
_Parsley_, _Columbine_, &c. ’tis also evident, that the _Lignous Body_ is
not there in the least Concave, but standeth perfectly in the Center; and
that the Insertions being gradually multiplied afterwards, the _Pith_ at
length, towards the thicker parts of the _Root_, shews and enlarges it
self. Whence it appears, that in all such _Roots_, the _Pith_ is not only
of the same substantial nature, and by the Insertions doth communicate
with the _Cortical Body_; and that it is also more or less augmented
by it; which is true of the _Pith_ of all _Roots_; but is moreover, by
mediation of the said Insertions, wholly originated from it. The various
appearances of the _Insertions_ and _Pith_ from the Fibrous Parts to the
top of the _Root_, see in _Fig. 9_, _10_, _11_, _12_, _13_, _14_. The
Pores of the _Lignous Body_, entire in the said Fibrous Parts, are best
seen when they have lain by a night dry, after cutting.
A farther evidence hereof are the Proportions betwixt the _Cortical
Body_ and _Pith_. For as about the inferiour Parts of the _Root_, where
the _Pith_ is small, the _Cortical Body_ is proportionably great; so
about the top, where the _Pith_ is enlarged, the _Cortical Body_ groweth
proportionably less, _sc._ because by its Insertions, ’tis gradually
bestowed into the _Pith_. Likewise the peculiar frame of some _Roots_,
wherein besides the _Pith_, the _Lignous Body_ being divided into a
double Ring, there is also a thick Ring, of a white and soft substance,
stands betwixt them; and is nothing else but the Insertions of the
_Cortical Body_ collected into the said Ring; but, towards the top of the
Root, being inserted again, thus maketh a large and ample _Pith_; as in
_Fennel_-Roots is seen.
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_.