prefent the Skin and its external Membrane; SECT. XVII. The Structure of the Trunk in an THE Trunks of Trees and Plants do confift of much the fame Parts as the Roots, namely, of veffical Globules, and various Tubes for conveying Sap and Air. Thus it has been obferved by Malpighi and Grew; but however in a different Difpofition and Proportion in respect to each other, than in the Roots, and in feveral Plants with a very great Diversity, as to Size, Number, Place, &c. as may be feen in the faid Grew's Comparative Anatomy of the Trunks, in many Instances, but not without Aftonishment. One Example we have produced from him here in Tab. XIX. Fig. 2. in an Afb-Tree, the fourth Part of the Trunk whereof is reprefented as cut across : ABCD is the Bark; of which A B is the outmost Skin, and AHB the Sap or ligneous Tubes ranged by one another in circular Difpofitions next to the extreamest Skin; II is the veffical Matter of the Bark, which below at D and C, has another kind of Sap-veffels, difpofed in an arched or curved Order; DCFE is the Wood; DQLK, KL KL MN, and MNFE, are the fourth part of three circular Superficies, each compofing a great Tube from Top to Bottom, in fuch manner, that one of 'em grows every Year about the Tree; the real Wood is SSS; between S and T are the round Orifices of the Air-veffels, which are difperfed thro' the whole Wood, being larger in the inmost Part of the Circles KL, MN, E F, and leffer in the outmoft; E F G is the Pith; ee the Bladders thereof; and Oo Oo are the Infertions, in which the veffical Textures of the Pith and Bark have a Communication with each other. Hitherto these abovemention'd Naturalifts have only discover'd a veffical Structure, and afcending Sap and Air Tubes; but Leuwenhoek has likewife difcover'd Veffels therein that run horizontally; and whereas the Figures of Malpighi and Grew do reprefent in general the Trunk and Root, and the Parts and Veffels of which, according to their Remarks, the fame are compofed; we may yet farther understand the Kinds of thofe Veffels as they have been obferved with great Accuracy by the faid Leuwenhoek, and drawn by him from the Life. SECT. XVIII. The Trunks grow upwards, and the Roots downwards. Now if ever there occur'd in Nature a surprising Phænomenon capable of obliging the moft obdurate Atheist to acknowledge, that in the growth of Plants, a wonderful Wifdom, Power and Goodnefs, has had its own Ends in view, and has carried 'em on even contrary to the Imagination and Opinion of Men, 'tis certain the fame is here difplayed moft evidently, and after fuch a manner as has hitherto been infcrutable even to the greateft Philofophers: The Wonder which we are ufhering in with fo much Pomp, and upon which fuch fuch famous Naturalifts as the Gentlemen of the Royal Academy of France, do likewife beftow the name of Wonder, in their Hiftories for the Years 1700, and 1702, is that Law to which we fee fo many Trees and Plants inceffantly fubfervient: According to which the Roots of all Seeds are for ever found to grow downwards, and the Trunks thereof to grow upwards. SEC T. XIX, XX, XXI. Three Experiments made upon Beans, Acorns, and other Trees. To give an Idea of what we have just now faid very briefly; It is known, that in all Seeds there is not only a little beginning of a future Plant and Root, as may appear from the Beans, &c. but we likewife find, that the Pluma and Rootfprout of which we have treated above, have a determinate Place in all Seeds, out of which they fhoot at first according to a determinate Course; but when they proceed, we always fee that the Trunk afcends, and the Root defcends into the Earth. They that defire to make a Tryal of it, may imitate that of Mr. Dodart, a Member of the French Academy, with very little Pains and Trouble; I my felf have done it with feveral Beans, and to my great furprize, found it not to fail in any: 'Tis thus, if you fplit a Bean (Tab. XVIII. Fig. 9.) and feparate two Lobes or Pieces of which it is compofed, from each other, having firft fteep'd the faid Bean 24 Hours in Water, and then dryed it as long after, till it begins to fhoot out as at 2, which will be the Root, you will fee at the Pluma, which is to be the Trunk lying in a hollow Place on one fide; and in the other at 3, another little Cavity, in which the Pluma is likewife preferved: If then you take another of these Sprouting Beans, and Plant it as at A, fo that the Root 2 extends extends itself downwards, it won't seem strange to any one that the Root-Stalk 2 (vide B) fhoots downwards, and the little Trunk i upwards, forafmuch as the Situation of both of 'em do naturally tend thereto. But it will be very surprising, when one takes the Bean C, and lays it upon its fide flat in the Earth, that the Root 2, and the Trunk 1, do not grow horizontally, which muft have come to pafs, if they had continued the pre ceeding Course, as the Bean feemed to determine it; inftead of which we discover, that both the Root 2, and the Trunk 1, make a Bow or a crookee Line, in order to proceed downwards and upwards: But to come to the utmost ; can a Man fee without Aftonishment, that when he plants the Bean inverted, that is to fay, with the Root upwards, and the Trunk downwards, yet the Trunk I winds itself about the Root upwards; and in like manner the Root 2 making a Semicircle about the Trunk or Plume, takes its Course downwards. Now that these Figures may not appear fomewhat improper, it is to be obferved, that the little Trunks I, I, I, at B, C, D, are drawn here before they were fo old, that they could properly make their Appearance in the Air. See the Memoirs of the French Academy 1700. p. 18. Now that this does not only happen in Beans, is fhewn by the faid Mr. Dodart, in the Hiftory of the French Academy, 1702. p. 62. That Gentleman found in the Month of December, fome Acorns lying in a heap upon a moist Place where the Ground was firm and compact, as in a beaten Path: Many of thefe Acorns had fhot out their Root in the Air without being in the Earth, and their little Roots came all of 'em out of the Point or Top of each Acorn, having the length of from 4 to 18 Lines, or 12 Parts of an Inch; and that which was wonderful was, that every one of thefe Roots bent them felves the fhorteft way towards the Earth, as if they all fought for it. This was therefore the more ftrange, because he did not obferve any of the Acorns, whofe Points tended downwards, fo as that if they had grown ftreight out, they could have reach'd the Earth; but on the contrary, he found one Acorn among 'em, the Point of which grew upwards, and in that he faw that the Root fhot ftreight up about an Inch in length, but that it afterwards changed its Courfe, and as it grew, turned downwards to the Earth. This then gave him a handle to make the following Experiment: He took fix of those Acorns, and fet 'em in a Flower-pot, after the manner as you may fee in Tab. XVIII. Fig. 10. at A, that is with the Point ftreight upwards, fo that the Roots that were to fpring from 'em, feemed not capable of growing any other way than upwards; he cover'd them with Earth of about two Fingers thick, and let 'em remain in the Pot the fpace of two Months, in which time they had fhot out; and the Root having now acquired fome length, made clofe to the Acorn an Inflection and Turn; and fo in the reft of the Acorns, they grew down again, feeking as 'twere a depth of Earth, juft in the fame manner as at B: And now the Confequence certainly feems to be, that all these Roots having once taken this Courfe of growing backwards from the Point to the Tail, they would perfift in it, and purfue their Course again right forwards; for which reafon he took thefe Acorns and inverted 'em again, preffing the Earth down quite round 'em, to the end that it might touch every Part; fo that they ftood as at C, with their Root now turned upwards, which before at B tended downwards. In this Condition he left 'em two Months more, and the Event was, that having uncover'd them, he found that there was nothing VOL. II. X x lefs |