PART II.

HAVING before given the Anatomy of Trunks; I shall next proceed to see, what Use may be made thereof; and principally, to explicate the manner of their Vegetation. In doing which, that former Method, which I used in shewing the manner of the Growth of Roots, I shall not exactly follow. For so, in regard the Organical Parts of the Root and Trunk are the same, and consequently their Nutrition and Conformation are effected in the same way; I should hereby be obliged to a nauseous and unprofitable repetition of many things already said. The Explication therefore of all those Particulars, which more especially belong to the Trunk, or are more Apparent therein, and not spoken of, or not so fully, in the former Books, will be my present Task. The chief Heads whereof, shall be these Seven following, viz.

FIRST, the Motion and Course of the Sap.

SECONDLY, The Motion and Course of the Aer.

THIRDLY, The Structure of the Parts.

FOURTHLY, The Generation of Liquors.

FIFTHLY, The Figuration of Trunks.

SIXTHLY, The Motion of Trunks.

SEVENTHLY, And lastly the Nature of Trunks as variously fitted for Mechanical Use.

CHAP. I.

Of the Motion and Course of the Sap.

FIRST, as to the Course of the Sap, there are Three Parts in which it moveth; sc. the Pith, the Wood and the Barque. First the Pith; in which the Sap moveth the First year, and only the First year. Or, it is Proprium quarto modo, to the Pith of every Annual Growth, and to the Pith of such a Growth only, To be succulent. That is, whether of a Sprout from a Seed, or of a Sucker from a Root, or of a Cyon from a Branch; The Pith is always found the First year full of Sap. But the Second year, the same individual Pith, always becomes dry, and so it continues ever after.

2. §. One cause whereof is, that the Lymphæducts in the Barque, being the first year adjacent to the Pith; they do all that time, transfuse part of their Sap into it, and so keep it always Succulent. But the same Lymphæducts, the year following, are turned into Wood; and the Vessels which are then generated, and carry the Sap, stand beyond them, in the Barque. So that the Sap being now more remote from the Pith, and intercepted by the new Wood, it cannot be transfused, with that sufficient force and plenty as before, into the Pith; which therefore, from the first year, always continues dry.

3. §. THE SECOND Part in which the Sap moves, sub forma liquoris, is the Wood. Which yet, it doth not in all Plants, but only in some; and visibly, in very few; as in the Vine: In a Vine, I say, the Sap doth visibly ascend by the Wood. And this it doth, not only the first year, but every year, so long as the Vine continues to grow. But although this ascent, in or through the Wood, be every year; yet it is only in the Spring, for about the space of a Month; sc. in March and April.

4. §. There are many other Trees, besides the Vine, wherein, about the same time of the year, the Sap ascendeth, though not so copiously, yet chiefly, in the Wood. For if we take a Branch of two or three years growth, suppose of Sallow, and having first cut the same transversely; if the Barque be then also transversely, and with some force, pressed with the back of the knife, near the newly cut end; the Sap will very plainly rise up out of the utmost Ring of Wood. And if it be pressed in the same manner, or a little more strongly, about an Inch lower, the Sap will ascend out of every Ring of Wood to the Center. Yet at the same time, which is to be noted, there ariseth no Sap at all out of the Barque.

5. §. Whence appears the Error of that so Common Opinion, That the Sap always riseth betwixt the Wood and the Barque. The contrary whereunto is most true, That it never doth. For the greater part of the year, it riseth in the Barque, sc. in the inner Margin adjacent to the Wood, and in Spring, in or through the Wood it self, and there only.

6. §. THE THIRD Part in which the Sap ascends, is the Barque, as was above hinted, and may be observ’d in almost any Branch, if cut cross, in the late Spring and in Summer; either as the Sap issueth spontaneously, or upon pressing, as aforesaid. So that when the Sap ceaseth to ascend, sub forma liquoris, by the Wood, then it begins to ascend by the Barque.

7. §. Besides the difference of Time, the Organical Parts likewise, in which these two Saps ascend, are divers. For in the Barque, it ascendeth visibly, only in the Succiferous, whereas in the Wood, it ascendeth only by the Aer-Vessels.

8. §. FROM what hath been said, we may understand, what is meant by the Bleeding of Plants. If we take it generally, it properly enough expresses, The eruption of the Sap out of any Vessels. And so, almost all Plants, in Summer time, do Bleed, that is, from Sap-Vessels, either in the Barque, or in the Margin of the Pith: the Saps they Bleed, having either a Sower, Sweet, Hot, Bitter, or other Tast. At which time, the Vessels also, in the Barque of a Vine-Branch, do Bleed a Sower Sap.

9. §. But that which is vulgarly called Bleeding, as in a Vine, is quite another thing; both as to the Liquor which issueth, and the Place where it issues: that is to say, it is neither a Sweet, nor Sower, but Tasteless Sap; issuing, not from any Vessels in the Barque, but from the Aer-Vessels in the Wood. So that there is as much difference betwixt Bleeding in a Vine, or the Rising of the Sap in any other Tree, in March, and in July; as there is betwixt Salivation and an Hæmorrhage; or betwixt the Course of the Chyle in the Lactiferous Vessels, and the Circulation of the Blood in the Arteries and Veins.

10. §. NOW the Cause from whence it comes to pass, that the early Spring-Sap of a Vine, and other Trees, ascendeth by the Wood, is, In that the Generation of the young Sap-Vessels in the Barque, by which the Sap ascendeth all the Summer; is, in the beginning of Spring, but newly attempted. So that the Sap having not yet these Vessels to receive it, it therefore (pro hac vice) runs up the Aer-Vessels in the Wood. But so soon as the said Vessels in the Barque begin to be considerably encreased, the Sap, declining the Aer-Vessels, betakes it self to These, as its most proper Receptacles.

11. §. THE CAUSE also, why the Vessels of almost all Plants, upon cutting, do yield Sap, or Bleed; is the Pressure which the Parenchyma makes upon them. For the Pith and other Parenchymous Parts of a Plant, upon the reception of Liquor, have always a Conatus to dilate themselves. As is manifest from Sponges, which are a Substance of the same Nature, and have a somewhat like structure. As also from Cork, which is but the Parenchyma or Barque of a Tree. I say therefore, that the Parenchyma being fill’d and swell’d with Sap, hath thereby a continual Conatus to dilate it self; and in the same degree, to press together or contract the Vessels which it surroundeth. And the said Vessels being cut, their actual Contraction and the Eruption of the Sap, do both immediately follow.

12. §. IT may be also noted, That the Trunk or Branch of any Plant being cut, it always bleeds at both ends, or upwards and downwards, alike freely. Which, as well as divers other Experiments plainly shews, That in the Sap-Vessels of a Plant, there are no Valves.

13. §. FROM what we have now above, and elsewhere formerly said, we may also understand the manner of the Ascent of the Sap. As to which, I say, First, That considering to what height and plenty, the Sap sometimes ascends; it is not intelligible, how it should thus ascend, by virtue of any one Part of a Plant, alone; that is neither by virtue of the Parenchyma, nor by virtue of the Vessels, alone. Not by the Parenchyma alone. For this, as it hath the Nature of a Sponge or Filtre, to suck up the Sap; so likewise, to suck it up but to a certain height, as perhaps, about an Inch, or two, and no more.

14. §. Nor by the Vessels alone, for the same reason. For although we see, that small Glass-Pipes immersed in Water, will give it an ascent for some Inches; yet there is a certain period, according to the bore of the Pipe, beyond which it will not rise. We must therefore joyn the Vessels and the Parenchyma both together in this Service; which we may conceive performed by them in the manner following.

15. §. Let A B be the Vessel of a Plant. Let C E D F be the Bladders of the Parenchyma, wherewith, as with so many little Cisterns, it is surrounded. ♦ Tab. 39. ♦ I say then, that the Sap, in the Pipe B A, would, of it self, rise but a few Inches; as suppose, from D to L. But the Bladders D P, which surround it, being swelled up and turgid with Sap, do hereby press upon it; and so not only a little contract its bore, but also transfuse or strain some Portion of their Sap thereinto: by both which means, the Sap will be forced to rise higher therein. And the said Pipe or Vessel being all along surrounded by the like Bladders; the Sap therein, is still forced higher and higher: the Bladders of the Parenchyma being, as is said, so many Cisterns of Liquor, which transfuse their repeated Supplies throughout the length of the Pipe. So that by the supply and pressure of the Cisterns or Bladders F D, the Sap riseth to L; by the Bladders Q L, it rises to M; by the Bladders N M, it rises to I; by the Bladders O I, it rises to K; by the Bladders P K, it rises to E; and so to the top of the Tree. And thus far of the Motion of the Sap.

CHAP. II.

Of the Motion and Course of the Aer.

THE NEXT enquiry to be made, is, into the Motion and Course of the Aer. Where this question will first of all be asked; sc. Which way the Aer first enters the Plant; whether at the Trunk, Leaves, and other Parts above ground; or at the Root? I answer, That it enters in part, at them all. For the Reception, as well as Extramission whereof, the Pores are so very large, in the Trunks of some Plants, as in the better sort of thick walking Canes, that they are visible, to a good Eye, without a Glass; ♦ Tab. 19. ♦ but with a Glass, the Cane seems, as if it were stuck top full of holes with great Pins: being so large, as very well to resemble the Pores of the Skin in the end of the Fingers and Ball of the Hand.

2. §. In the Leaves of Pine, they are likewise through a Glass, a very Elegant Show; standing all most exactly, in rank and file, throughout the length of the Leaves. The Figure whereof shall be given hereafter, when we come to the Anatomy of the Leaf.

3. §. But although the Aer enters, in part, at the Trunk and other Parts, especially in some Plants; yet its chief entrance, is at the Root. Even as some Parts of Aer, may continually pass into the Body and Blood, by the Habit, or Pores of the Skin; but the chief entrance hereof, is at the Mouth. And what the Mouth is, to an Animal; that the Root is to a Plant.

4. §. Again, if the chief entrance of the Aer, were at the Trunk; then, before it could be mixed with the Sap in the Root, it must descend; and so move not only contrary to its own Nature, but likewise in a contrary Course to the Sap, throughout the Plant. Whereas, by its Reception at the Root, and so its Transition from thence; it hath a more natural and easie motion of Ascent. For while the Sap ascends, that the Aer, in the same Plant, should continually descend, cannot reasonably be supposed.

5. §. The same is further argued, From the fewness and smallness of the Diametral Portions in the Trunk in comparison with those in the Root. In which Nature hath plainly designed the same, for the Separation of the Aer from the Sap, after they are both together received thereinto. So that the Reception and Course of the Aer, is made on this manner following.

6. §. THE Aer being a Springy Body, it insinuates into all the Holes and Cranies of the Earth; and so is plentifully mixed therewith. Whereupon, as the Sap enters the Root, more or less Aer still intrudes it self together with it. The Liquid Portion of the Sap, swells and fills up the Succulent Parts of the Barque. The Aery Part, is, as was said, separated from the Liquid, into the Diametral Portions. Which running from the Barque towards the Centre of the Root, and so passing along betwixt the Aer-Vessels; do hereby convey the Aery Part of the Sap from the Barque, into the same.

7. §. Being thus received into the Aer-Vessels, and the Reception thereof, by the same means continued; it is by them advanced into the Trunk. In which advance, it is again, more or less, disbursed into all the Parts of the Trunk, as it goes. Partly, inwards to the Pith. From whence, the Pith is always, at length, filled with Aer. Partly, into the Insertions; by which it is conveyed outward into the Barque. Wherein, it is in some part, transfused through the Sap: and so the rest, with part of the Sap, remitted, in perspirations, back again into the Aer.

8. §. So that, whereas the Diametral Portions in the Root, do serve to convey the Aer from the Sap in the Barque, into the Aer-Vessels, in the Wood: on the contrary, the Insertions here in the Trunk, serve to convey the Aer from the Aer-Vessels in the Wood, into the Sap, in the Barque. Wherefore, as the Aer-Vessels advance the Aer, or the Aery Part of the Sap, and so convey it by the length of the Trunk; so the Insertions filter it, and convey it by the breadth.

9. §. AND that the Insertions have this Office or Subservience unto both Kinds of Vessels; doth yet further appear, if we consider, That the Aer-Vessels are always so postured, as to touch upon the said Insertions, or at least to stand very near them. For either they are large, and so do frequently touch upon them on both sides; as in Elm, Ash, Wallnut, &c. ♦ Tab. 28. 29. 22. ♦ Or if they are small; then they either run along in even lines collateral and oftentimes contiguous with the said Insertions, as in Holly: or at least, are reciprocally, some on one side, and some on another, inclined to them; as in Apple. ♦ 25. ♦ By all which means, the Aer is more readily conveyed from the Vessels into the Insertions.

10. §. A further evidence hereof is this, That generally, the bigger and the more numerous the Aer-Vessels be; the bigger, or at least, the more numerous also are the Insertions: Especially, if the comparison be made (as in all other cases it ought to be, as well as here) betwixt the several Species of the same Kind. So Corin, which hath small Aer-Vessels, ♦ Tab. 17. ♦ hath also very small Insertions. But the Vine, hath both very large: and so for others.

11. §. Wherefore, the Insertions minister betwixt the Aer-Vessels, and the Succiferous; in the same manner, as the Vesiculæ of the Lungs, do betwixt the Bronchiæ and the Arteries. That is to say, as in an Animal, the Bronchiæ deposite the Aer into the Vesiculæ of the Lungs; which administer it to the Arteries: so in a Plant, the Aer-Vessels deposit the Aer into the Insertions, that is into the Vesiculæ of the Insertions; by which it is gradually filtred off into the Barque and the Sap-Vessels therein.

CHAP. III.

Of the Structure of the Parts.

A THIRD enquiry, is into the Generation and Structure of Parts. The manner whereof I have already endeavoured to explicate from the Anatomy of the Root, throughout all particulars. Some whereof I shall yet further clear.

Lib. 2. P. 2.

1. §. As First, the Union of the Barque to the Body of the Tree, Contrary to the common Opinion, That they are not continuous; but that the Barque only surrounds the Body, as a Scabbard does a Sword, or a Glove the Hand. As also seemeth to be proved, by the easy Slipping of the Barque of Willow, and most other Trees, when full of Sap, from the Wood.

2. §. But, notwithstanding this, they are as truly continuous, as the Skin of the Body is with the Flesh: sc. by means of the Parenchyma; which is one entire Body, running from the Barque into the Wood, and so uniting both together; ♦ Tab. 19. ♦ as in a Branch of Vine or Corin-Tree, when the Barque is stripped off, is apparent; the Spaces between the several Parts of the Wood, being filled up with the Parenchymous, inserted from the Barque.

3. §. Now the reason why the Barque nevertheless slips so easily from the Wood, is plain, viz. Because most of the young Vessels and Parenchymous Parts, are there every year successively formed; that is, betwixt the Wood and Barque: where the said Parts newly formed, are as tender, as the tenderest Vessels in Animals. And we may imagine, how easie it were at once to tear or break a thousand Vessels or Fibres of an Embrio, of a Womb or Egg.

4. §. THE same Vessels of the Barque being always braced, and gradually falling off, together with the Parenchyma, into the utmost Rind: Hence it is, that the Barques of many Trees, are as it were, ♦ Tab. 19. ♦ latticed with several Cracks of divers Sizes, and sometimes in the Figure of Rombs: the said Fissures representing the Position and Tract of the Vessels in their Braces. Hence also it is, that the Barque of some Trees, as of Corin, Cherry, &c. falleth off in Rings, sc. because the Sap-Vessels are posited in the same manner in the Barque.

5. §. The Sap-Vessels, as they are generated at the inner Verge of the Barque: so likewise, in a small quantity, at the utmost Verge of the Pith. These being not only fed with a more vigorous Sap, but with great caution, secured within the Wood, for the propagation of the succeeding Buds.

6. §. Hence also it is, that is, by the annual accretion of these Vessels, that the Pith is sometimes less in the Trunk, than in the Branches; ♦ Tab. 18. ♦ and less in the elder Branches, than in the younger; and sometimes ’tis almost wholly filled up. By which means, as the Branches carry every year a greater burthen; so they become still more sturdy the better to support it.

7. §. SOMETIMES also the Pith breaks and shrinks up, thus making the Trunk a Pipe. The cause whereof, is either the Largeness of its Pores, or the Thinness of the Sides of the said Pores; upon both which accounts, the Pith doth more easily tear, and upon tearing shrink up, and so become hollow: as in Cichory, Lampsana, Sonchus, Teasel, Brownwort, and others; wherein the Pores of the Pith are Large, and the Sides of the Pores, Thin. Whereas, upon contrary accounts, the Piths of most Trees, remain perpetually entire.

8. §. THE Reason why Plants are made thus to become hollow, is partly, for the ripening of the Fruit or Seed; which is the better effected by a more plentiful supply of Aer continually received into their hollow Trunks. For by means of that Aer, part of the Sap, is dryed up, and the remaining part of it made warmer, and so sooner matured.

9. §. Partly, for the better determining the due Age of the Plant. Hence it is, that the greater part of Annual Trunks, are hollow: the Aer contained in that hollow, drying up the Sap, and shrinking up the Sap-Vessels so far, as to hinder the free motion of the Sap therein; from whence the Plant must needs perish. So that as the Content of the Aer-Vessels, is a kind of Vegetable Aer, whose Office is to Attenuate, and Ferment the Juyces of Plants: so the Content of these Cavities, cometh nearer to a more common Aer, designed chiefly, so soon as it is convenient, to dry them up.

10. §. AGAIN, as to the Aer-Vessels, divers questions may be asked. As how it comes to pass, that they are generally less in the Trunk of the same Plant, than in the Root? The Cause whereof is, that here in the Trunk they are more under the power of the Aer; both that which entreth in at the Trunk, and that which of its own Nature ascendeth up into it from the Root. For the Aer, as we have elsewhere said, is the Mould of the Aer-Vessels; to whose crooked or at least, Acid Parts, the Saline, and other Principles concurring to their generation, do conform. To which they do best, the smaller they are: the Fibres of the larger Aer-Vessels making greater Circles, and so coming nearer to a right Line, answerable to the Figure of the Particles, not of the Aerial, but of the Saline Principle.

11. §. Wherefore as the Aer-Vessels may be observed still to be dilated or widened towards the lower parts of the Root, the Aerial Principle being there less predominant, and the Saline more: So towards the upper part of the Trunk, to be contracted or grow smaller; the Aerial Principle being here more predominant, and the Saline less.

12. §. FOR the same cause it may be observed, That the Aer-Vessels of the Second years Growth, and the several years succeeding, are usually nearer of one Size, than those of the Second and First; all being under a less power of the Aer, than the First. For the first year the Pith being full of Liquor, the Aer-Vessels themselves, are the only Repositories of the Aer. Whereas after the first year, the Pith becoming dry, or another great Repository for the Aer; the Aer-Vessels are henceforth filled with a moister or more Vaporous and Saline Aer, and so made to grow wider.

13. §. Hence the very Size of the Pith, hath much influence upon the Aer-Vessels, and the manner of Nutrition, and the Generation of Liquors in Plants.

14. §. BUT for the most part, the Aer-Vessels are somewhat, more or less, amplified in every new Annual Ring; or at least to a certain number of years. Probably, because in the elder Branches, the Spiral Fibres, of which the Vessels consist, are more bulky; and so make a Vessel of a wider, as a more agreeable bore. Nature obtaining hereby, that the Quantity of Aer, shall always be answerable to the Growth of the Plant, or at least, be sufficient to maintain its Vegetable Life and Vigour.

15. §. And therefore, as is above hinted, it seems likely, That after a certain number of years, the Aer-Vessels are no longer amplified, but stand at a stay, and perhaps may grow smaller, according as the Tree is less or more Longæve; and that after this period, it is some way or other in its Declining State.

16. §. LASTLY, from the Content and Governing Principle of the Aer-Vessels, the Time, when they begin every year to be formed, or to appear, is always later; at least with respect to the season of the Tree. So that whereas the Sap-Vessels begin to be formed in Spring: these, not till the latter end of Summer, or there about; at least not till about that time to appear. That is, when the Sap begins to decrease, and to grow more Aery; and so more fit matter for the Generation of the said Aer-Vessels.

CHAP. IV.

Of the Generation of Liquors.

UPON the Structure and Formation of the Parts, dependeth the Generation of Liquors, as was lately intimated. The manner whereof I have formerly shewed, in discoursing of the Root. Yet some things I shall here further explicate. And First, what we have formerly asserted, sc. That the concurrence of two specifically distinct Fluids, is as necessary to Nutrition in Plants, as in Animals. Which appears, as from divers other considerations, so from the very Structure of a Plant: where in all the Organical Parts, or the Parenchyma and the Vessels, are every where mixed together per minima, that is, per minimas partes organicas, or Fiber with Fiber of several Kinds. Every small part of a Tree, or of the Barque of a Tree, being as I may say, a sort of Linsy-Woolsey. So that there is not the least part of the Sap, which is not impregnate with divers Essential Tinctures, as it is continually filtred from the Fibres of one Kind, to those of another; standing every where woun’d and stitch’d up together for the same purpose.

2. §. FROM the special Nature and Structure of the Parts, the Liquors of Plants are likewise specified. The Vessels being the chief Viscera of a Plant. For all Liquors in a Plant, are certainly made by that Plant. And since the Plant hath no Viscera (so called) I would then know, what its several Liquors are made by? If in the Parenchyma, surely by that Parenchyma. If in the Vessels, by the Vessels. And if of divers Kinds by divers Kinds of Vessels. So that what the Viscera are in Animals, the Vessels themselves are in Plants. That is to say, as the Viscera of an Animal, are but Vessels conglomerated: so the Vessels of a Plant, are Viscera drawn out at length.

3. §. AGAIN, as the specifying of the Sap dependeth chiefly on the special Nature of the Parts: so partly, upon the Structure of the Whole. Whereby every Part is still better accomodated with its own Juyce. Thus the Aer-Vessels are necessary, not only and barely for a supply of Aer; but also by their Number, Size, and Position to adjust the quantity of that Aer, to the government of Nutrition, and the Generation of the Specifick Liquors of every Plant. Which is evident from hence, in that they do not follow the Size of the Plant; but are great and many, in some small Plants; and small and few, in some others that are large. So Vines, and Corn, as we have formerly observed, have proportionably a great number of Aer-Vessels, and those very large. By which means the Sap is attenuated and less Oyly, and more copiously impregnated with a Subtle, Volatile and Winy Spirit.

4. §. For the same reason, the Stalk of Maze or of Indian Wheat, which when it is Green yieldeth a very sweet Juyce; and the Canes, whereof Sugar (which aboundeth with a volatile and inflammable Spirit) is made; these, I say, obtain the like over proportion of Aer-Vessels, to what we see in most other Plants. Hence also it is, that none of the said Plants have any considerable Barque; that so the attenuating and subtilizing Aer, may have a more easie and plentiful admission at the Trunk also. For which reason likewise the Pores of the Skin of some Canes are, as hath been said, remarkably wide.

5. §. Hence also it is observable, that of the same Species or Kindred, those Plants which have the most, and especially the largest Aer-Vessels; have also the greatest abundance either of a sweet, or of a winy Liquor. So in Apple; they are larger than in Crab; In Warden, larger than in Quince; and in Pear-Tree, larger than in Warden. So also in Corin, larger than in Gooseberry; and in Vine, larger than in Corin: and so in others.

6. §. AND as the Aer-Vessels, by their Multitude and Largeness, are accommodated to the better making of a Winy Sap: so by their fewness and smallness, of an Oylie. As is remarkably seen in Fir, and other Resiniferous Trees: these having, if not the smallest, yet the fewest Aer-Vessels of all other Trees.

7. §. IF it be asked, how a Plant comes to have any Oyl at all in any Part? Since we see, that the Sap by which the Root is fed, seemeth to be nothing else but Water: and that many Plants which yield a great deal of stillatitious Oyl, as Mint, Rue, and others, will yet grow in Water: I say, if it be enquired how this Water, is made Wine or Oyl? I answer, that there is no such matter. But that the Oyl, and all other Vegetable Principles are actually existent in, and mixed per minima, though in an extraordinary small proportion, with the Water. Even as we see the distilled Waters of Anise Seeds, Penyroyal, and the like to be impregnated with their own Oyls, which give the Taste and Smell to such Waters.

8. §. Wherefore, as a certain quantity of any Salt may be dissolved in Water; beyond which, it will not mix therewith, but remains under its own Form: So is there a certain proportion of Oyl, though far less, which may also be perfectly mixed with Water; and is certainly so, more or less, with all the Water in the world. But if that proportion, or degree of impregnation be once exceeded; the particles of Oyl do then, and not till then, gather into a body, and appear under their own Form.

9. §. I say therefore, that all kinds of Vegetable Principles, are either in or together with the Water, with less difference first received into a Plant. But when they are once therein; they are then separated, that is to say, filtred, some from others, in very different Proportions and Conjunctions by the several Parts; the Watery by one Part, the Aery by another, the Oyly by another, and so the rest: and so every Part is the Receptacle of a Liquor, become peculiar, not by any Transformation, but only the Percolation of Parts out of the common Mass or Stock of Sap. And so all those parts of the Sap, which are superflous to any kind of Plant, are at the same time, discharged back by Perspirations, into the Aer.

10. §. AND, that Nature, in the various Percolations and Sepations of the Sap, may still the better answer her end; hence, it is, that she carefully seeth, not only to the special Nature and Proportion of the Organs, by which she doth her work; but likewise to their very Position. Thus it is observable, That whereas the Lymphæducts, which carry a more Watery Liquor, are still placed on the inner Verge of the Barque, next to the Aer-Vessels: the Lactiferous and Resiniferous Vessels of Plants, to whose Oylie Liquor a mixture of much Aer is incongruous; do usually stand, neither on the inner, nor the outer verge of the Barque; but in the midle. By which means, they are at the greatest distance, and so most secure, from the Aer; either that which enters the Barque at the Circumference, or from the Wood and Pith.

11. §. AND because the Resinous Liquors of Plants are more Oily, than their Milky; their security therefore, from the approach of the Aer, is yet further contrived. In that in Pine, and other Resinous Trees, the Diametral Insertions are never found; or at least, not visible: which yet in other Trees, are conspicuous; being those Parts, whose office it is, to introduce the Aer from the Aer-Vessels into the Barque.

12. §. AGAIN, the Milky Liquors of Plants being thinner than the Resinous, and having a considerable quantity of Water mixed with their Oyl; hence it is, that in Milky Plants, as in Rhus, there are a greater number of Lymphæducts; and those standing nearer to the Milky Vessels, than they do in Pine and the like, to the Resinous. By which means they are better fitted to affuse their Aqueous Parts more plentifully to the said Milky Liquor.

13. §. FROM the Mixture of Watery Parts with the Oylie, it comes to pass, that whereas all Lympha’s, Mucilages, and Rosins are transparent; the Aquæ-oleous Liquors of Plants are Milky or white, or otherwise Opacous. For the same thing is the cause of the whiteness of Vegetable, as of Animal-Milk: that is to say, a more copious mixture of Watery and Oily Parts per minima, or into one Body. For even the Serous and Oylie Parts of Animal Milk, when throughly separated one from the other, they become very transparent. So the Stillatitious Oyl of Anise Seeds, is most transparent and limpid, even as Water it self: yet there is a known sort of White Anise-Seed Water, as it is commonly called: that it is to say, wherein the Oyl, in distillation, ariseth and is mixed more plentifully with the Water. And the Water, wherein the stillatitious Oyl of any Vegetable is dissolved, becomes a perfect white Milk; as in this Honourable and Learned Presence, I have formerly had occasion to shew the Experiment.

See the Discourse of Mixture

14. §. AND that the Milky Liquors of all Vegetables whatsoever, are more Oylie than their Lympha’s, is most certain. For all those Gums, which dissolve either in Oyl or in Water, as Galbanum, and the like, are originally the Milky Juyces of Plants. And if you take the Milk of any Plant, as for instance, the Milk of common Sumach, or of any Taste, Bitter, Astringent, Hot, Cold, or any other whatsoever; and having well dryed it, and then fired it at a candle; it will thereupon burn with a very bright and durable flame, even like that of Tar or Turpentine it self.

15. §. FROM what hath been said, we may likewise gather the most genuine import of the word Gum, and the distinction thereof both from a Rosin and a Mucilage. First, a Rosin, is originally a Turpentine, or Acidoleous Liquor, having an exceeding small quantity of Watery Parts mixed therewith; and which, for that reason, will not be dissolved in Water, but only in Oyl. Of this kind are Mastick, Benzoine, Taccamahacca, and divers others, commonly, in our Bils to Apothecaries, called Gums. Yet in strict speaking they are all so many Rosins.

16. §. Secondly, a Gum, and every Oylie Gum, is originally a Milky Liquor, having a greater quantity of Water mixed with its Oyly Parts; and which for that reason, will be made to dissolve either in Water or Oyl. Of this kind are Sagapen, Opopanax, Ammoniac, and others.

17. §. The third sort of Gum, is that which is Unoylie, and which therefore dissolveth only in Water, as Gum-arabick, the Gum of Cherry-Tree, and others such like. This Gum, though commonly so called, yet is properly but a dryed Mucilage: being originally nothing else but the Mucilaginous Lympha issuing from the Vessels of the Tree. In like manner, as it doth from Cumfry, Mallow, and divers other Plants: and even from the Cucumer. The Vessels whereof, upon cutting cross, yield a Lympha, which is plainly Mucilaginous, and which being well dryed, at length becomes a kind of Gum, or rather a hardened Mucilage. In like manner, the Gums of Plum-tree, Cherry-tree and the like, are nothing else but dryed Mucilages. Or, if we will take the word in its widest sense, then all Gums are originally, either a Terebinth, or a Milk, or a Mucilage.

18. §. I have likewise made divers Observations of the Tasts, Smells, and Colours of Plants, and of their Contents, since those I last published: and that both for the finding out the true Causes of their Generation, and also the applying of them unto Medical and other Uses. Of which hereafter.

CHAP. V.

Of the Figuration of Trunks.

THE Fifth Head, shall be, of the Figuration of Trunks. Which also, as well as the making of Liquors, dependeth upon the Structure of the Parts. As First, almost all Shrubs (cæteris paribus) have a greater number of Aer-Vessels; and those of a smaller Size; and consequently much spread abroad, as most easily yielding to the magnetick Power of the Aer, according as we have more fully demonstrated, in speaking of the Vegetation of Roots: as in Elder, Hazel, Fig, Sumach, and the like. By which spreading, the said Aer-Vessels do sooner, and more easily strike into the Barque, and so produce collateral Buds and Branches, and that upon the first rising of the Body from the Root: that is, the Plant becomes a Shrub.

2. §. BUT if the said Aer-Vessels are very large, they will not yield so easily to shoot out collaterally; and so the Trunk grows up taller and more entire: as in Oak, Wallnut, Elm, &c. wherein they are exceeding large, is seen. Hence also the Vine, if supported, will grow to a prodigious length. And Hops and Bryony, are some of the tallest, amongst all Annual Growths: the Aer-Vessels of all which, are very large. Whereas Borage, and many other like Plants, although the Pores of their Parenchyma, are vastly wide, and filled with Sap; yet because their Aer-Vessels are small, they are therefore but Dwarf-Plants. Wherefore the tallness or advancement of a Plant or Tree, dependeth not upon the Plenty of Sap, how great soever, but on the Largeness of the Aer-Vessels.

3. §. AGAIN, as a Plant or Tree grows either Shrubby, or Tall and Entire, according to the Size of the said Vessels: so from their Position, doth it grow Slender or Thick. So, where they keep more within the compass of a Ring, as in Elm, and Ash, the Tree, in proportion, usually grows taller, and less thick. But where the said Vessels are spread more abroad, and especially are postured in Rays, as they are in Oak, the Tree grows very thick. Because the said Vessels thus standing all along nearer to the Insertions, there is a more ready and copious passage of the Aer out of the one into the other; and so the Diametral growth of the Wood is more promoted.

4. §. LASTLY, from the same general cause it is, That the Trunks of Vegetables are either Round or Angular. Those of all Trees are Round. Because the Barque, being here thicker, and the Aer-Vessels bound up with a greater quantity of Wood; the Aer hath not sufficient power to move them, and the Barque with them, into those various Positions or Figurations, as the Trunks of Herbs do yield to.

5. §. Yet the cause of the various shapes of the Trunk, is not the Aer alone; but partly, the Principles of the Plants themselves, in conjunction therewith; according to the predominion whereof, and chiefly of some certain kind of Salt or Salts, as I shall hereafter more particularly explicate, the Trunk is Square, Triangular, Pentangular, or otherwise Figured. And thus much in general of the Figuration of Trunks.

B. 4. P. 1. Ch. 6.

CHAP. VI.

Of the Motions of Trunks.

THE Motions also of Trunks are various. Principally Four; sc. Ascending, Descending, Horizontal, and Spiral. The cause of the Ascent of a Plant, is a certain Magnetick Correspendence betwixt the Aer and the Aer-Vessels of a Plant; the Motion and Tendency whereof, the whole Plant follows. This I have asserted, and I think, clearly demonstrated in my First and Second =Books= of the Anatomy of Plants. I will here add this plain Experiment.

2. §. Take a Box of Moulds, with a hole bored in the bottom, wide enough to admit the Stalk of a Plant, and set it upon stilts half a yard or more above ground. Then lodg in the Mould some Plant, for Example a Bean, in such sort, that the Root of the Bean standing in the Moulds may poynt upwards, the Stalk towards the ground. As the Plant grows, it will follow, that at length the Stalk will rise upward, and the Root, on the contrary, arch it self downward. Which evidently shews, That it is not sufficient, that the Root hath Earth to shoot into, or that its Motion is only an Appetite of being therein lodged, which way soever that be: but that its nature is, though within the Earth already, yet to change its Position, and to move Downwards. And so likewise of the Trunk, that it rises, when a Seed sprouts, out of the Ground, not meerly because it hath an Appetite of being in the open Aer; for in this Experiment it is so already; yet now makes a new Motion upwards.

3. §. BUT although the Natural Motion of the Trunk be to Ascend; yet is it forced oftentimes to Descend. For the Trunk-Roots growing out of some Plants near the ground, and shrinking thereinto, like so many Ropes, do pluck the Trunk annually lower and lower into the ground together with them; as may be seen in Scrophularia, Jacobæa, and many other Plants.

4. §. IF these Trunk-Roots break out only about the bottom of the Trunk, as in the aforesaid Plants, then the Trunk gradually Descends into the Earth, and is turned into a Root. But if it be very slender, and the Trunk-Roots break forth all along it, then it Creeps horizontally; the said Roots tethering it, as it trails along, to the ground; as Strawberry, Cinquefoyl, Mint, Scordium, &c.

5. §. AS to their Spiral Motion, it is to be noted; That the Wood of all Convolvulus or Winders, stands more close and round together in or near the Center, thereby making a round, and slender Trunk. To the end, it may be more tractable, to the power of the external Motor, what ever that be: and also more secure from breaking by its winding Motion.

6. §. Wherefore, Convolvulus do not wind by any peculiar Nature or Genius, which other Trunks have not; but because their Parts are disposed so, as to render them more sequaceous to the external Motor. Even as the Claspers of a Vine, having the like Structure, have also a Motion of Convolution: whereas the Branches themselves upon a contrary account, move in a straight Line.

7. §. The Convolution of Plants, hath been observed only in those that Climb. But it seems probable, that many others do also wind; in which, the main Stalk, is as the Axis to the Branches round about. ♦ B. 2. P. 1. Ch. 1. ♦ Of which number, I conceive, are all those whose Roots are twisted; a Motion we observed in speaking of the Root. Whether it be so, or not the Experiment may easily be made by tying a Thred upon any of the Branches; setting down the respect it then hath to any Quarter in the Heavens: for, if it shall appear in two or three Months, to have changed its Situation towards some other Quarter; it is a certain proof hereof. And that hereby the Roots of many Plants become twisted; the Motion beginning in the Stalk, and ending at the bottom of the Root, which stands always fixed in the same place.

8. §. The Convolution of Trunks, is made not one, but divers ways; some moving by South from East to West; and others from West to East. Wherefore it seemeth, that as the Efficient Cause of Convolution, is not within the Plant, but external: so also, that it is not One, but that there are Two Great Efficients of this Motion; sc. the Sun and the Moon. Some winding together with the Sun, in its Diurnal Motion, (or, if the Earth moves, then, Inclining to the Sun) by South from East to West. And others winding with the Moon, in its Monthly Motion, from West to East.

9. §. This possibly, may also be one sensible way of distinguishing betwixt Solar, and Lunar Plants. Thus far, in general, of the Motions of Trunks.

CHAP. VII.

Of the Nature of Timber or Trunks, as they serve for Mechanick Use.

THE last thing I purposed to speak of, is, Those several Qualities of Timber or of Trunks, by which they are fitted for Mechanical Use. As Hardness, Softness, Fastness, Clevesomeness, Toughness, Brittleness, Durableness, or any of the same Qualities compounded. The Visible Causes whereof are observable, Partly, in the Structure of the several Parts; sc. the Insertions, Sap-Vessels and Aer-Vessels; as to the Number, Size, or Position of any of them. And partly, in the Nature of the Parts; I mean such as is manifest to sense. According to our clear and distinct observing of all which Causes, we may understand, Wherefore any Wood is made use of for any certain purpose. And also, wherein fitly to apply it to further Use. In order to which, a compleat History of the Mechanical Uses of Vegetables would very much conduce. I shall for the present give some Instances.

2. §. AS First, some Woods are soft, as Deal, and Sallow. Yet from different Causes. Deal, from the great Porosity of the Wood it self, or the large Pores amongst the Sap-Vessels. But Sallow, from the great number of Aer-Vessels spread all over it. And therefore, though they are both soft, yet will not serve for the same purposes; Sallow being well wrought upon, which way soever you cut it: but Deal, especially the white Deal, if it be cut cross, it tears, and will never polish or work smooth.

3. §. Again, in Sallow, by the equal spreading of the Aer-Vessels, the Softness is equal or alike in all Parts. For which cause it maketh an excellent Coal for Painters Scribets. Because it doth not only make a light Stroak, but every where certain; and so doth not disturb the even Motion of the Hand. For the same cause, Shoemakers also make use of it for their Carving-boards. Because being every where equally soft, it turns not the edge of their Knives, Which Deal would presently do; because though very soft in some places, yet in others ’tis hard; that is to say, on the inner Verge of every annual Ring of Wood, where the old Sap-Vessels grow much more compact and close together.

4. §. AGAIN, some Woods are soft, but not fast; others are both, as Linn: its Softness, depending on the numerousness and equal spreading of the Aer-Vessels; its Fastness, on the closeness of the true Wood, and the shortness, and smallness of the Insertions. For which cause, it is of excellent use for many purposes; and particularly, for small Sculpture: such as may sometimes be seen for the Frames of Looking-Glasses, or of smaller Pictures in Water-Colours.

5. §. SOME Woods, again, are fast, and hard, as Elm. Its hardness depending upon the closeness of the Wood. Its fastness, Partly, upon the same cause; and partly, on the smalness of the Insertions; as also on the fewness of the Aer-Vessels in proportion with the Wood; and on the thwart and cross Position of many of them. Hence it is, that Elm, of all others, is the most Cross-grain’d Timber; that is, cleaveth so unevenly, to and fro, according to the cross Position of the said Vessels.

6. §. Hence also it cleaveth the most Difficultly. Even then, when it is without any Knots. For which reason it is always used, as best for the Hub of a great Wheel. As also for Water-Pipes, and for Pumps. Not because it is the most durable Wood; but because it will not split or crack, either in the working, or afterwards. For the very same reason, it is used for Coffins; that is, because, it will not split in working: not because it will endure longest under ground; for Pales are always made of Oak. So also the Ladles and Soles of a Mill-wheel are always made of Elm; as also the Keel of a Boat, sc. lest they should split: but the other Parts are made of Oak.

7. §. It may here also be noted, That the Planks commonly called Groaning-Boards, lately exposed, as a kind of Prodigy, to the view and hearing of many People, were of Elm. The Aer-Vessels of this Wood, being, though not more numerous, yet more ample, than in any other Timber. So that upon the application of the Red-hot-Iron, as was usual, and thereby the Rarifaction of the Aer and Watery Parts in the Timber; every Vessel became, as it were a little Wind-Pipe for their Expiration. And as a great many Drops falling together in a showr of Rain; so a great many of these Pipes playing together, might make a kind of big or groaning noyse.

8. §. AS Elm, of all Woods, is one of the fastest; So, on the contrary, of all hard Woods, Oak is the most Cleavesome, or splitteth the most easily. The cause whereof is, partly, the Largeness of the Insertions; and partly, the Diametral or Radiated Position of most of the Aer-Vessels: upon both which accounts, wherever a crack is once begun, ’tis easily continued throughout the Diameter of the Trunk.

9. §. AGAIN, some Woods are hard, fast, and tough. So is Ash, and especially Beech. Hard and fast, from some of the same Causes, as Elm. Tough not from the Structure, but from the Nature of the Parts; whose Principles are united in a more exact proportion. Wherefore London-Cars have the Rings of their Wheels of Beech; because it tears more difficulty than even Ash it self. Whence also for large Screws, there is no Wood like it. But for Small Screws, of about an Inch Diameter, Birch is the best; as being, though not so hard, yet more tough.

10. §. THE more Brittle a Wood is, ’tis likewise usually the more durable. So Oak, which, with respect to its hardness, is not a tough, but very brittle Wood, is almost as durable as any. Whereas Beech, Birch, and the like, although very tough; yet for Duration, are of no service; for there are no Woods will rot sooner: and therefore, though strong enough, yet unfit to make any Standing Parts of Building, or of Furniture; especially in wet and moist places. Because, these Woods, having a less proportion of Oyl, than there is in Oak; they are apter to imbibe the moisture even of a dank Aer; by which moisture, they either Rot, or breed Worms, which destroy them.

11. §. HENCE it is, that what we call the Heart of Timber, as it is more brittle, so also more durable; sc. Because more Oylie. So that which is called the Sap of Oak, is much more tough than the Heart, although the Heart be more durable. That is to say, the older the Wood is, the Watery Parts are the more evapourated, whilst the Oylie still remaine, as a kind of Tincture or Extract in the Wood. Even as we see, that the older Seeds of any one Kind, are more Oylie than those that are green and young. So that the Oylie or Rosinous Parts of the Sap, are a kind of Embalming to the Heart, or older Part of a Tree, securing it from the destructive impressions of the Aer. For which Cause it is, that Oak, Yew, Cocus, Guajacum, &c. which are Oylie Woods, have always much Heart, whereas Birch, Alder, Beech, Maple, which are very Unoylie, have never any Heart.

12. §. FROM hence likewise we may understand the Cause of the Toughness of Flax: what we call Flax, being only the Sap-Vessels, or Lignous Fibres of the Barque. And generally, the Barque of any Tree, as of Willow (whereof are usually made a sort of Ropes) is very tough. The Vessels being here younger, and less Oylie than in the Wood. So likewise Hemp, is nothing else but the Sap-Vessels of the Barque of the Plant so called. And Scotch-Cloath, is only the Housewifery of the same Parts of the Barque of Nettle.

13. §. WHENCE it is very probable, that there are many other Plants, as well as the above named, whereof might be made good Tow. And of some, especially in some respects, better than of Flax it self. Because that even Hemp, although it will not make so fine a Staple, as Flax (for all our fine Hollands are made of Flax) yet Flax, which is but of the same fineness as Hemp, will never, by all the Art yet known, be made so white as Hemp is made. The Qualities therefore of the best Tow, that can be in Nature, are that the Staple be long, small, tough, and white. So that if in the Barque of any Plant, we can find these Qualities, or any of them, to excell; we may be sure, it will be of better use, in some respects, for the making of Cloath, or other purpose, than Flax it self.

14. §. I WILL conclude with one Instance more, and that is as to Grafting. The good and happy success whereof, doth certainly depend upon the suitableness or respondence betwixt the several Parts of the Stock and Cyon; as the Barque, Wood, and Pith; and that both as to the Number, Size, and Position of the said Parts, and of their several Pores or Vessels: according to the degrees whereof, the Conjunction (cæteris paribus) will be more or less prosperous. So that of all such Conjunctions as are found to be apt and taking, and which some have learned not without long Practice and Experience; another, only by comparing the Branches of Trees together, may with little trouble, and in much less time, inform himself. By the same means, some Conjunctions which seem to be strange, as Quince and Pear, White Thorn and Medlar, &c. do yet, by the respondence of their Parts, as well as by Experience, appear to be good. And there is no doubt, but that many Conjunctions not yet tryed, or not known to have been so, may upon the same ground, be tryed with good success.

15. §. The chief Use of Grafting and Inoculation, is, That they Accelerate the growth of Good Fruit. The Cause whereof, is the Knot, which is always made in the Conjunction. By means of which, all the Sap is strained, and so ascendeth up into the Graff or Bud, both Purer and in less Quantity; and is therefore better and sooner concocted. Hence, the smaller the Fruit of any Tree, though it be not the best, yet the Sap being there, in less Quantity, is the sooner ripe. On the contrary, where the Sap ascendeth too freely, it doth not only retard the growth of the Fruit, but produceth Barrenness; as is seen in those luxuriant Branches, where it runs all up to Leaves. Hence also Vines, by Bleeding, become more Fruitful: that is, by the Effusion of Part of the Sap, there is a more easier melioration of that which remains. Even as Phlebotomy doth oftentimes produce a more healthful and better Habit of our own Bodies. To conclude, the lessening the Quantity, and thereby the melioriation of the ascending Sap, by Knots, is Natures own contrivance; as is seen in Sugar-Cane, Corn, and other Plants.

THE

ANATOMY

LEAVES, FLOWERS, FRUITS and SEEDS.

In Four Parts.

The FOURTH BOOK.

By NEHEMJAH GREW M.D. Fellow of the ROYAL SOCIETY, and of the COLLEGE of PHYSICIANS.

LONDON, Printed by W. Rawlins, 1682.

THE

CONTENTS

OF THE

First Part.

CHAP. I.

Of the Protections and Folds of Leaves.

CHAP. II.

Of those Things which appear upon the Surface of the Leaf.

CHAP. III.

Of the Figures of Leaves; and the Apparent Position of the Fibres.

CHAP. IV.

Of the Parts and Texture of the Leaf.

CHAP. V.

Of the Duration of Leaves, and the Time of their Generation.

CHAP. VI.

Of the Manner of the Generation of the Leaf. Where also, that of the Two General Parts of a Plant, sc. the Lignous and Parenchymous, is further explain’d.

To the Honourable

Robert Boyle Esq;

SIR,

AFTER I had finished the foregoing Books, In which, I conceive, as far as Glasses will yet lead us, I have clearly Describ’d and Delineated the Structure of a Plant; and have endeavour’d, in some part, to Unfold the Reason and Scope of Nature therein: I was willing to sit down, and leave what remained, to the Improvements of the Present and Succeeding Ages.

But in Discourse upon this Subject, You have been pleased frequently to insist, That I should by no means omit, to give likewise, some Examples of the Mechanisme of Nature in all the other Parts. The Performance whereof therefore, next to the Obedience I owe to the Royal Society, is to be looked upon, as a Due to the Authority which Your Judgment hath over me.

This I have said, that, if what is herein done, shall prove acceptable unto Learned Men; they may know, To whom they are once more to give their Thanks: After they have so often done it, upon (a better score) the Publishing of Your own Excellent Works. In which, there seems to be a Question, Whether Your Continual Endeavours, to enlarge the Bounds of Natural Knowledge, or Your Successes therein, have been the Greater. So that, whereas Nobility in some, doth only serve to lift them, like Jupiter’s Satellits, out of sight: You, by giving a greater Light, have drawn all Mens Eyes upon You. And whilest there are many, in all Ages, fond of Preheminency in the Conduct of Popular Affairs; who yet rarely hit the Mark they aim at; or aim at That they pretend: You have thought fit, rather to separate Your Self, to that more Innocent, and more Noble Sort of Wisdom, which lieth, not in the Arts of Conceiling, but in Discovering, the Truth of Things.

That we may have many to imitate You herein, cannot but be heartily wish’d by all, who regard the Honour of their own Country; as it is, with much Zeal, by

Sir,

Your most obedient

Servant

NEHEMJAH GREW.

THE

ANATOMY

LEAVES,

PROSECUTED

With the bare EYE,

And with the

MICROSCOPE.

Read before the Royal Society, Octob. 26. 1676.