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.