37. §. The said Ætherial parts of the Aer, have a Power over the Aer-Vessels not only thus to Dispose them; but also to Sollicite and spread them abroad from the Center towards the Circumference of the Root. By which means, those Roots which have no Pith in their lower parts, obtain one in their upper.⁠[30] And the same Pith, which in the lower part, is ratably, small, in the upper, is more or less enlarged.⁠[31]

38. §. The Spreading of these Vessels is varied, not only according to the Force the Aer hath upon them, but also their own greater or less Aptitude to yield thereto. As often therefore, as they are Slenderer, they will also be more Pliable and recessive from the Centre, towards the Circumference. Hence, in such Roots where they are small, they stand more distant; Tab. 2, & 6. as in Turnep, Jerusalem Artichoke, Potato’s, and others; and so their Braces are fewer: and in the same Root, where they are smaller, their distance is greater. Besides, in these smaller Aer-Vessels, the Rings being less, and the Spiral Fibres whereof they are made, continuing to shoot; the said Rings therefore, must needs be so many more, as they are smaller; and so take up more space by the length of the Root; and so, not being capable of being crowded in a right line, every Vessel will be forced to recede to a crooked or bowed one.

39. §. The Sap Vessels, being by the Parenchymous Fibres knit to these, will likewise comply with Their motion, and spread abroad with them. Yet being still smaller⁠[32] and more pliable than the Aer-Vessels, and so more yielding to the intercurrent Fibres of the Parenchyma, their braced Threds will, sometimes, be much more divaricated, than those of the Aer-Vessels; Tab. 6. as in Jerusalem Artichoke. And because the Succiferous Vessels, although they are joyned to the Aerial by the Parenchymous Fibres,⁠[33] yet are not continuous with them; neither fall under the like Attractive Power of the Aer, as the Aerial do; the Aerial therefore, upon their spreading, do not always carry all the Succiferous along with them; but often, if not always, leave many of them behind them sprinkled up and down the Pith; Tab. 6. as in Parsley, Carrot, Jerusalem Artichoke, Turnep, &c. may be seen.

40. §. The spreading of the Aer-Vessels still continued, several of them, at length, break forth beyond the circumference of the Root; and so are distributed, either in the lower parts, into Branches and Strings; or at the top, into Leaves. And lest they should all spread themselves into Leaves, and none be left for the Caulis; as where they are very small, or the Sap-Vessels to bound them, are but few, they might; therefore divers of them are, oftentimes, more frequently braced in the Centre; Tab. 6. for which reason, they cannot so easily separate and spread themselves from thence, but run more inwardly up into the Caulis, as in Borage.

How the whole Root is differently sized and shaped. 41. §. FROM THE various Sizes, Proportions, and Dispositions of the Parts, Roots are variously sized, shaped, moved and aged. Those which, by their Annual Growth, are large; have fewer, both Aerial, and Sap-Vessels, and a more copious Parenchyma. So that the Aer-Vessels, or rather, the Aery Ferment contained in them, volatilizing only a smaller portion of the Sap; the said Sap is less capable of advancement into the Trunk; and so must needs remain and fix more copiously in the Root, which is thereby more augmented. And where the Sap-Vessels alone, are but few, the Root is yet, ratably, somewhat large: but where they are numerous, it is never so, as to its Annual Growth, in any proportion to their Number: Because their Tincture, which is Alkaline, will go farther in setting the Parenchymous Parts: than the Tincture of These, which is Acidulate, will go, in setting Them.⁠[34]

42. §. When the Aer-Vessels are more pliable and sequent to the Attraction of the Aer, and so spread themselves, and the Succiferous together with them, more abroad; in the manner as hath been said; the Root also will grow more in Breadth; Tab. 2, & 7. the nutrition of the Parenchymous Parts, to which the Vessels are adjacent, being thus, by the same dimension, more augmented; as in Turnep, Jerusalem Artichoke, &c. Tab. 7, & 8. But where these are not spread abroad, the Root is but slender; as in Asparagus, Dandelion, &c.

43. §. If the Aer-Vessels be contracted into, or near the Centre, and are somewhat Large or Numerous; and the Succiferous, also more copiously mixed with, or surrounding them; the Root grows very Long; as do those of Fenil, Vine, Liquirish, &c. Tab. 2, & 17. For the Aer-Vessels containing a more copious Ferment, it will well digest and mature the Sap: Yet the Succiferous being over proportioned to them; the Sap will not therefore, be so far volatilized, as to ascend chiefly into the Trunk; but only to subserve a fuller Growth of their Vessels: which being more numerous, and so more sturdy, and less sequent to the expansive motion of the Aerial; this their own Growth, and consequently, that of all the other Parts, cannot be so much in Breadth, as Length.

44. §. Where the same Aerial Vessels are Fewer, or more Contracted, or sheathed in a Thicker and Closer Barque; Tab. 7, 8. the Root is smooth, and less Ramified, as in Asparagus, Peony, Dandelion. But where more Numerous, sheathed in a Thinner Barque, Smaller, or more Dilated; the Root is more Ramified, or more Stringy, Tab. 2, & 7. as in Columbine, Clary, Beet, Nicotian. For being, as is said, by these means, more sequent to the Attraction of the Aer; approaching still nearer the circumference of the Barque, they at last strike through it, into the Earth. And the Parenchymous Fibres being wrapped about them, and the Succiferous Vessels knit to them by those Fibres;⁠[35] therefore they never break forth naked, but always invested with some quantity of these Parts as their Barque: where by, whatever Constitutive Part is in the main Body of the Root, the same is also in every Branch or String.

45. §. From the same Expansion and Pliability of the Aer-Vessels, the Root oftentimes putteth forth Root-Buds; which gradually shoot up and become so many Trunks. In the Formation of which Buds, they are pliable and recessive all kinds of ways; being not only invited Outward, toward the Circumference of the Root, as in Root-strings, but also spread more Abroad every way, so as to make a Root-Bud: Where as in the said Root-strings, they are always more Contracted. Tab. 6. Which, in respect of the Disposition of the Parts, is the principal difference betwixt the Root and the Trunk, as hath been said.⁠[36] Hence, those Roots, chiefly, have Root-Buds,Tab. 11. which have the smallest Aer-Vessels;⁠[37] these, as is said, being the most pliable and Expansive.

46. §. But because the expansiveness of the Vessels, dependeth also, in part, upon the Fewness of their Braces; therefore the said Buds shoot forth differently, in divers Roots. Where the Braces are fewer, the Buds shoot forth beyond the Circumference of the Root, as in Jerusalem Artichoke; Tab. 6. where more close, as in Potato’s, the Buds lie a little absconded beneath it; the Aer-Vessels being here, by their Braces, somewhat checked and curbed in, while the Barque continueth to swell into a fuller Growth.

47. §. If the Aer-Vessels are all along more equally sized, the Root is so also, or Cylindrical; as are those of Eryngo, Horse-Radish, Marshmallow, Liquirish, &c. But if unequal, growing still wider towards the bottom of the Root; then the Root is unequal also: But groweth, as is observable, quite contrarily to the Aer-Vessels; not Greater, as They do; but still smaller, or pyramidally; as in Fenil, Borage, Nettle, Patience, Thorn-Apple, &c. is apparent. For the Aer-Vessels being considerably wider about the bottome of these Roots; they there contein a more Copious Ferment: Whereby the Sap is there also more volatilized, and plentifully advanced to the Upper Parts. Withal, thus receiving into themselves, and so transmitting to the upper Parts, a more plentiful Vapour, they hereby rob the Parenchymous Parts of their Aliment, and so stint them in their Growth.

How Roots are differently Mov’d. 48. §. FROM THE different Proportions and Situation of the Parts, the Motions of Roots are also various. For where the Aer-Vessels are spread abroad and invested with a thinner Barque; Tab. 8. the Root runs or lies Level, as in the level-Roots of Primrose, Bishops-weed, Anemone, &c. may be seen. So that these Roots, as by the Perpendicular Strings, which shoot from them into the Earth, and wherein the Aer-Vessels are contracted into their Center, they are Plucked down⁠[38]: So by the Aer-Vessels, which stand nearer the Aer, and more under its Attractive Power⁠[39] they are invited upwards; whereby they have neither ascent nor descent, but keep level, betwixt both.

49. §. But if these Vessels are Contracted, standing either in, or near the Centre, and are invested with a Barque proportionably Thick; the Root striketh down perpendicularly, as doth that of Dandelion, Bugloss, Parsnep, &c. Tab. 7, 8. And therefore the said Vessels, although they are spread abroad in the level Roots, yet in the perpendicular ones of the same Plant, they are always contracted; as by comparing the Level and Down-right Roots of Ammi, Primrose, Jerusalem Artichoke, Cowslip, and others, is manifest.

50. §. If the Aer-Vessels are Contracted, and Environed with a greater number of Succiferous, the Root grows deep; that is, perpendicular and long.⁠[40] Perpendicular, from the Contraction of the Aer-Vessels;⁠[41] and long, from the Predominion of the Succiferous, which in their growth, are extended only by that Dimension, as in Liquirish, Eryngo, &c.

51. §. If the Succiferous are over proportioned to the Parenchymous Parts, but under to the Aer-Vessels; the Root is perpendicular still, but groweth shallow: The Succiferous being sturdy enough to keep it perpendicular; Tab. 7. But the Aer-Vessels having a predominion to keep it from growing deep; as in Stramonium, Nicotian, Beet, &c.

52. §. If, on the contrary, the Parenchymous Parts are predominant to the Aer Vessels; and that, both in the Root and Trunk; then the whole Root changeth place, or descends.⁠[42] For the said Aer-Vessels, having neither in the Trunck, nor in the Root, a sufficient Power to Draw it upwards; it therefore gradually yields to the Motion of its String-Roots; which, as they strike into the Soil, Pluck it down after them. And because the old Strings annually rot off, and new ones successively shoot down into the Ground, it therefore annually still descendeth lower; as in Tulip, Lily, &c. may be observed.

53. §. Where the Aer-Vessels are much spread abroad, and also numerous, the Root oftentimes, as to its several parts, descends and ascends both at once. So Radishes and Turneps, at the same time, in which their nether parts descend; their upper, (where the said Vessels are more loosely braced, and spread more abroad than in the lower parts) Tab. 2. do ascend, or make their Growth upward. Hence also, the upper part of most young Roots from Seed, ascends: Because the first Leaves, being proportionably large, and standing in a free Aer, the Aer-Vessels therein, have a dominion over the young Root; and so themselves yielding to the solicitation of the Aer, upwards; they draw the Root, in part, after them.

How Roots are differently Aged. 54. §. BY THE Situation and Proportions of the Parts, the Age of the Root is also varied. For if the Sap-Vessels have the greatest Proportion, the Root, is Perennial, and that to the farthest extent, as in Trees and Shrubs. Because these Vessels containing a more copious Oyl;⁠[43] and their several Principles being more closely Concentred, they are less subject to a Resolution, that is, a Corruption or Mortification by the Aer.

55. §. If the Parenchymous Parts have much the greatest, the Root seldom liveth beyond Two Years; but afterwards perisheth either in whole, or in part; as do divers bulbous, tuberous, and other Roots; whether they are more Porous and Succulent, or more Close and Dry. If Porous, all the Liquid Principles standing herein more abundant, either by a stronger Fermentation, or otherwise, Resolve the fixed ones of the Organical Parts; whence the whole Root, rots; as in Potato’s. So also Parsneps, and some other Roots, which, in a hard and barren Soil, will live several years, in another more rank, will quickly rot. If the Parenchyma be Close, then the Aer, chiefly, entring in and filling it up, thus mortifies the Root; not by Rotting the Parts, but over Drying them; as in Satyrion, Rape-Crowfoot, Monkshood, &c.⁠[44]

56. §. But if the Aer-Vessels have the greatest Proportion, and especially if they are more large, and withall, are spread more abroad: the Root is Annual, as in Thorn-Apple, Nicotian, Carduus Ben, &c. Tab. 9. And of the same Kindred, if any, those are Annual, which have the most Aer-Vessels. So Endive and Sonchus, which have store of Aer-Vessels, are both Annual: whereas Cichory, in which they are fewer, is a Perennial Root. For hereby a more copious Aer being Transfused into all the other Parts;⁠[45] they are thus, by degrees, hardened, and become sticky; and so impervious to the Sap, which ought to have a free and universal Transition from Part to Part. As Bones, by Precipitations from the Blood, at length, cease to grow. Or the same more abundant Aer, so far volatilizeth the Liquors in the Root, that they are wholly advanced into the Trunk, and so the Root is starved. Whence also the Aer-Vessels of the Trunk; where they are numerous, and over proportioned to the Bulk of the Root, as in Corn; they so far promote the advance of the Sap, as to exhaust the Root, sucking it into a Consumption and Death.

How the Contents of the several Parts are made. 57. §. FROM THE Principles of the Parts, their Contents and the several Qualities hereof are also various;⁠[46] the Fluid of each Organical Part, being made, chiefly, by Filtration through the sides thereof; such of the Principles in the Sap, being admitted into, and transmitted through them, as are aptest thereunto. In the like manner, as when Oyl and Water, being poured upon a Paper, the Water passeth through, the Oyl sticks: or as the Chyle is strained through the Coats of the Guts, into the Lacteal Vessels: or as Water in Purgations, is strained through the Glands of the same Guts, from the Mesenterical.

58. §. The Principles therefore of the Parenchymous Fibres being spirituous, acid, and aerial, they will also admit the like into them; excluding those chiefly which are Alkaline and Oleous.⁠[47] And as by the Conjugation of such Principles in the Fibres, the like are capable of admittance into their Body: so the Proportion and Union of the same Principles, regulates the transmission hereof into their Concave. Wherefore, the predominant Principles of the Fibres being chiefly acid, next spirituous, and aery, the more aery ones will be transmitted. For if more of them should fix they must do so by similitude and adhesion: But where there are fewer similary parts to adhere to, fewer must adhere. The Fibres therefore contain so many parts of Aer, as to admit many more into their Body; but not to fix them; which therefore must needs, upon admission, pass through into their Concave; where, together with some other more spirituous parts, they make an Ætherial Fluid. And because some aqueous or vaporous parts will also strain through with them; hence it is, that as more and more of these enter, they by degrees still thrust out the aery ones; which quitting the more succulent Fibres of the Parenchyma, are forced to betake themselves to the dryer ones, scil. all those, whereof the Diametral Portions do consist. For the same reason the Aery parts being gradually excluded the succulent Fibres of the Barque; they are forced to recede and transmigrate into those of the Pith. And the Fibres of the Pith themselves being filled, and the Aery parts still forced into them; they at length also strain through the Fibres into the Bladders: whence it comes to pass, that while the Barque is succulent, the Pith is often times filled with Aer.

59. §. The Lymphæducts being more earthy, Salinous; oleous, and P. 2. §. 21. aqueous, will both admit and copiously fix the like Principles, as their proper Aliment. The Water being more perfluent than the rest, will therefore strain, with a lighter Tincture of them, into their Concave. Especially the Oleous parts of these being rampant, and less apt to fix and seize the aqueous, upon their entrance, than the saline.

60. §. The Lactiferous, appearing to be made, chiefly, by the Constipation of the Parenchymous Parts all round about their Sides; the Liquor conteined in those Parts, although it may easily enough be transfused into the Hollow of these Vessels; yet seems it not, with equal facility, to be refunded thence: So that the thinner and more aqueous Portion only, passing off; the remainder, is, as it were, an Oleous Elixyr, or extract, in the form of a Milk.

61. §. The Fluid Ferment contained in the Aer-Vessels, is also in part, dependent on the Principles of those Vessels, being in their percolation tinctured therewith. But because the percolation is not made through the Body of the Fibres whereof the Vessels are composed, but only betwixt them; therefore the transient Principles more promiscuosly, yet with an over porportion of dryer Particles, pass into the Concaves of these Vessels, and so are herein all immersed in a Body of Aer.⁠[48] The Fibres themselves, in the mean time, as those of the Parenchyma, admitting and containing a more Aery and Ætherial Fluid.

62. §. The Contents are varied, not only by the Nature, but also the Proportion and Situation of the Parts, whereby the said Contents are with different Facility and Quantity, communicated one to another. Hence it is, partly, that a Vine, or that Corn, hath so little Oyl: sc. Because their Aer-Vessels, in proportion with the other Parts, are so Great and Numerous: in Corn, the Stalk being also very hollow, and so becoming as it were, one Great Aer-Vessel. For the Oily parts of the Sap, are so exceedingly attenuated⁠[49] by the Aery Ferment contained in these Vessels; that they are, for the most part, so far immersed in the Spirit, or mixed therewith, as not, by being collected in any considerable Body, to be distinguishable from it. And the affinity that is betwixt Spirits and Oils, especially Essential, is manifest: Both are very inflammable; Both will burn all away; The Oders, which we call the Spirits of Plants, are lodged in their essential Oyl; Both, being duly Rectified, will mix as easily together, as Water and Wine. So that, although Oyl, by the separation of its earthy and Saline parts, which give it its sensibly oleous Body, may not be so far attenuated, as to produce a Spirit; yet that it may so far be attenuated, and so be mixed therewith, as not to be discerned from it, as in the forementioned Plants, will be granted.

63. §. Hence it is, that the Lactiferous standing more remote from the Aer-Vessels, and the Succiferous interposing;⁠[50] the Liquor, therefore, contained in them, is not so much under the government of the Aerial Ferment, and is thence, partly, more Oily. For the same reason, all Roots which are Milky, so far as I have observed, have an under-proportion of Aer-Vessels, these being either Fewer or Smaller.

How the Odours of Plants are made. 64. §. FROM what hath been said, we may receive some information, likewise, of the Odours, Colours, and Tastes of Plants. And for Odours, I suppose, That the chief Matter of them, is the Aerial Ferment contained in the Aer-Vessels. Not but that the other Parts do also yield their smell; but that these yield the strongest and the best, and immediately perceptible in fresh, undryed and unbruised Plants. For the Aer entring into, and passing through the Root, and carrying a Tincture, from the several Organical and Contained Parts, along with it, and at last entring also the Concaves of the Aer-Vessels; it there exists the most Compounded and Volatile Fluid, of all others in the Plant, and so the fittest matter of Odour: and such an Odour, as answers to that of all the Odorous parts of the Plant.⁠[51] Wherefore the Organical Parts, being well clensed of their Contents, smell not at all; Because the Principles hereof are, as hath been said, so far fixed and concentred together. Hence also the Contained Parts themselves, or any other Bodies, as their Principles are any way more fixed, they are less Odorous: So is Rosin, less than Turpentine, and Pitch, than Tar; and many the self same Bodies, when they are coagulated, less than when they are melted. So also Musk, which is not so liquid as Civet, is not so strong; nor Ambergreece, as Musk: For although it hath a more excellent smell, than Musk hath, yet yieldeth it not so easily; since it is a more fixed Body, and requireth some Art to be opened. Hence also the Leaves of many Plants lose their Odour upon rubbing: Because the Aer-Vessels being thereby broken, all their contained odorous Fluid vanisheth at once: which before, was only strained gradually through the Skin. Yet the fixed Parts themselves, upon drying, are so far altered by the Sun and Aer, as to become resoluble, and volatile, and thence odorous.

How their Colours. 65. §. SO ALSO of their Colours. As whence the Colours of the Skins are varied. For divers of the Sap-Vessels, together with the Parenchymous Parts successively falling off from the Barque into the Skin⁠[52] by their proximity to the Earth and Aer, their Sulphureous or Oleous Principle is more or less resolved, and so produceth divers Colours. So those Roots which turn purple any where within, have usually a blacker Skin; the one of those two Colours being, by a resolution and corruption of parts, easily convertible into the other, as in Cumfry, Thistle, &c. So the Milk of Scorzonera, contained in the Vessels of the Barque, upon drying, turneth into a brown Colour: Wherefore the Skin, in which there are divers of those Vessels, is of the same. So both the Milk and Skin of Lovage is of a brownish yellow. But Parsnep hath a clearer Sap in all its Vessels, and a whiter Skin. So Potato’s, being cut traverse, after some time out of ground, have divers red specks up and down where the Vessels stand, and their Skin is accordingly red.

66. §. The reason, I say of these Colours, is the resolution or reseration of the Principles of the several Parts, chiefly, by the Aer, and a lighter mixture of them consequent thereupon: whereby the Sulphureous or Oyly Parts, which were before concentred, are now more or less rampant, discovering themselves in divers Colours, according as they are diversly mixed with the other Principles. Hence these Colours are observable, according to the nature of the Parts wherein they are, or whereunto they are adjacent: So where the Lympheducts doe run, there is a Red, or some other Sulphureous Colour; the Oleous Principles being, as is said,⁠[53] more copious in these Vessels; as in the Bark of Peony, the inward parts of Potato’s, &c. may be seen. But the Parenchymous Parts, where more remote from the said Vessels, they are usually White, or but Yellow: the Sulphureous Principle of these Parts, being, as hath been said, but sparing.⁠[54] The same is seen in those Roots which shew both Red and Yellow: those Parts, principally, where the Succiferous Vessels run, being Red; but those Parts, where only the Aer-Vessels are mixed with the Parenchymous, being Yellow; as in Patience. So likewise the pithy part of a Carrot, where the Aer-Vessels have very few Succiferous mixed with them, is Yellow; but the Barque, where the Succiferous are very numerous, is Red. For the same reason, many Roots, which are Whiter in their upper parts, are Purple or Reddish in their inferiour, as Avens, Strawberry, &c. Because those lower parts, having lain longer⁠[55] under ground (these being descending Roots) their Principles are, thereby, somewhat more resolved, and so the Oleous, ramp and spread all over the rest in that Colour.

67. §. And that the Resolution of the Sulphureous and other Principles is partly effected by the Aer, appears, In that, where the Aer hath a free access to the Succiferous Vessels, the Colours are there, chiefly produced, or are more conspicuous. So in Potato’s, where the Succiferous Vessels are either next to the external Aer, as in the Skin; or contiguous with the Aer-Vessels, as in the Ring within the Barque; there, they produce a Red: but where more remote from both, as in the middle of the Barque, and Centre of the Root, there they produce none. Hence also it is, that the Leaves and Flowers of some Plants, as Bloodwort, Wood-Sorrel, Radish, Jacea, &c. although Green or White in the greatest portion of their Parenchymous Part; yet where the Succiferous and Aer-Vessels run together, they are of Red, Blue, and other Colours; the Oleous parts of the one, being unlocked and opened, by the aery of the other.

How their Tastes. 68. §. AND LASTLY, of their Tasts. Most Roots which are acres or bitting, have a very copious Parenchyma in proportion with the Succiferous Vessels, as of Arum, Dragon, and others: Because the Saline and other Principles are not so much hot, by any sufficient quantity of Sulphureous, from those Vessels, in which the Sulphur, as is said, is more abundant;⁠[56] but rendred rather pungent, from some Spirit and Aer. But divers Umbelliferous Roots, especially which abound with Lactiferous Vessels, are hot; as Fenil, Lovage, Angelica, &c. Yet is it not their Oyl alone that makes them hot, but the combination thereof with the Saline Parts: as is manifest, from the nature of the Seed of these Plants; wherein, as the Oyl is most copious; So being held to a Candle till they burn, constantly spit; which cometh to pass, by the eruption of the Saline Parts: and is the very same effect, with that which followeth upon burning of Serum or Blood. And therefore, as these Seeds are more hot, they also spit the more; So those of Cumine, which, though fulsom, yet are not so hot, spit less; Fenil and Dill, which are hotter, more; there being a greater quantity of volatile Salt contained herein. Hence all Essential Oyls are hot, the Spirit and volatile Salt, being incorporated herewith. And some of them will shoot, and crystallize as Salts do, as that of Anise; which argues a mixture of a considerable quantity of volatile Salt. As also doth the Nature of these Oyls, in being amicable to the Stomach, Carminative, and sometimes Anodyne; scil. as they kill some fetid, or corrosive Acid: for volatile Salts themselves will have the like operation in some cases as these Oyls.