A Letter of Mr. Martyn Lister, Written to the Publisher from York, Januar. 10. 1671/2, Containing an Ingenious Account of Veins by Him Observ'd in Plants, Analogous to Human Veins

A Letter of Mr. Martyn Lister, written to the Publisher from York, Januar. 10. 1674, containing an Ingenious account of Veins by him observ'd in Plants, analogous to Human Veins. SIR, I am very much pleased, when you give me to understand, that something is published of the Anatomy of Vegetables, and that more is designed by that excellent person Signior Malpighi*. And since the receipt of your last, I have perused the very ingenious Book of Dr. Grew; and, as far as I have observed these matters, all things therein are faithfully delivered, and with great sagacity. In turning over my Notes, made some years agoe, I find, among other things of this nature, some few Observations concerning the Veins of Plants or such Ductus's, as seem to contain and carry in them the noblest juices of Plants. Of these there is little or no mention made in this curious Tractate, unless under the notion of Pores. And because I am of the opinion, that they will prove vessels Analogous to our Human Veins, and not meer Pores, they shall, if you please, be the Subject of your entertainment in this Letter; and the rather that, if they prove Veins (as I little doubt them) they are not to be passed over in silence, but are early to be accounted for in the Anatomy of Vegetables. To avoid ambiguity: Those parts of a Plant, which Pliny (lib. 16.cap.38.) calls by the names of Veneæ and Pulpaæ, are nothing else, in my opinion, but what our late late Author, Dr. Grew, calls Fibres and Infertments, or the Lignous body interwoven with that which he tooks to be the Cortical, that is, the several distinctions of the Grain. Now, that the vessels, we are about to discourse of, are not any of the Pores of the Lignous body (to use the Doctor's terms) is plain in a traverse Cut of Angelica Sylvestris magna vulgariter f.B., for example; the Veins there very very clearly shew themselves to an attentive view to be distinct from Fibres, observable in the Parenchyma of the same Cortical body together with themselves; the Milky juice still rising besides and not in any fibre. Also in the like cut of a Burdock in June, the like juice springs on this and on that side of the radii of the Woody circle, that is, in the Cortical body and pith only. Again, where there is no pith, there is none of this juice to be observed, and consequently none of these Veins as in the Roots of plants, and Trunks of trees; but ever in the Bark of either. I need not here enumerate the many Plants, wherein these particulars are most plainly observable, as in Sphondylium, Cicutaria, many of the Thistle kind, &c. Further, Neither are they probably of the number of the Pores, described by our Author in the Cortical body, or Pith. Not surely of those Pores extended by the breadth, because the course of the juice in these vessels is by the length of the plant; as I have sometimes very plainly traced in the pith of a dried Fennel-stalk, following them by dissection quite through the length of the pith. It remains, that, if Pores, they are of those pores of the Cortical body, that are supposed to be extended by the length thereof; which yet seems (to me at least) not enough, but we think them vessels invested with their own proper membranes, analogous to the Veins of our Humane body; for these reasons: 1. Because they are to be found in the Pith, and sometime in the Cortical body of a plant, not included within the common Tunicle of any Fibres, as is above noted: (that Fibres, or the Seminal root are cloathed, is most plain in some plants, as in Fern and Geranium Batrachoides, the Fibres of the former are coated, at least in some parts of the plant, with a black skin, in the latter likewise with a red one:) And in these cases, had they not, I say, their own proper membranes, we see no cause, why the very porous and spongy body of the Pith and Cortex, should not be in all places filled alike with the juice, and not rise (as most plainly it doth) in a few determinate and set places only, that is, according to the position and order of these vessels. 2. Again the Experiment I made, which you were pleased to publish*, concerning the effect p.2122, &c. of a ligature on *Cataputia minor Lobel.* viz. the sudden springing of the milky juice out of infinite pores besides the incision: (the cause of which phenomenon I take to be, the dissected veins impetuously discharging themselves of part of their juice within the porous *Parenchyma* of the bark;) whence it is probable, that, if there was no coated vessel to hold this milky juice, we might well expect its springing upon the bare ligature, as when we squeeze a wet sponge; the external cuticle of the plant, as this experiment shews, being actually perforated. In the next place it is very probable, that these vessels are in all plants whatsoever. For, as it is truth-like of all the other substantial parts of plants, that they are actually in, and common to all plants, though specified by divers accidents in figure and texture; so of these veins, which, though they be discernable mostly in those plants where they hold discoultoured juices, yet we may very probably think, that they are wanting, where the eye finds not that assistance in the challenging of them. As in these very plants, where they are least visible, there is yet a time when they are, if not in all, yet in some parts of these plants, plain enough to the naked eye: The tender shoots of the Greater and Lesser Maple, in May, are full of a milky juice; viz. the known liquor of these veins. Again to this purpose, If you apply a clean knife blade to a travers cut of the like shoots of Elder, the gummy liquor of these veins will be drawn forth into visible strings, as is the nature of bird-lime, of the bark of Holly, or the milk of *Cataputia minor Lobel.* Further, The leaf stalks of our garden Rubarb do sometimes shoot (by what accident, we enquire not here) a transparent and very pure Chrystallin Gumm, though the veins, that held this gummy juice, are by no ordinary means visible in them, and yet by comparing the nature and properties of this gum, with that of the gums of other vegetables, we cannot doubt but this gum-rubarb is the juice of these veins, as well as we are assured, the gum of other vegetables to be of theirs, by the same comparative anatomy. Lastly, we think, that even Mushromes (that seemingly inferior at imperfect order of vegetables) are not exempt and destitute. destitute of these Veins, some of them yielding a milky juice, hot and fiery, not unlike some of the Spurge kind, or Euphorbium. It might be expected, that I should add somethings at least, concerning the Original and Productions of these Veins, if not an exact description of them, the course of the juices in them, and their more immediate and primary uses in the matter of Vegetation: But I must acquaint you, that (besides the season is not now proper to improve and verify, if I had leisure, the Observations formerly noted, and that they were things thrown into my Adversaria without other order, than that nothing should slip from me in the quest of Medicaments, that might be of light) although I find indeed many scattered particulars (besides them already delivered) concerning the Position, Order, Number, Capacity, Distributions, Differences, Figure, &c. of these Veins; you will be pleased to take in good part, if I think fitting to reserve them until the opportunity of another Summer's review: It seeming to me no small matter, to have fairly hinted the existence of them to such curious persons as shall have the leisure, and find themselves in better circumstances, than I can pretend to, as to those great advantages of Glasses. Designing, &c. To conclude with the primary use of these Veins; which is, in my opinion, to carry the Succus nutritius of Plants, because, where they are not, there is no Vegetation; as it is seen, if an engrafted Branch or Arm be bared and stripped off the clay, &c. in June, all the course of Vegetation will appear to have been made only by the Bark, and not by the Wood, that is, in the place only, where these veins are. A secondary use is the rich furniture of our Shops; for, from these Veins only it is, that all our Vegetable Drugs are extracted, and an infinite more might be had by a diligent enquiry, and some easy means, which I have not unsuccessfully put in practice; witness the black Resin, I not long since sent you a specimen of.