The anatomy of plants with an idea of a philosophical history of plants, and several other lectures, read before the royal society / by Nehemjah Grew ...

CHAP. IV. Of the Generation of Liquors.

UPON the Structure and Formation of the Parts, de∣pendeth the Generation of Liquors, as was lately in∣timated. 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 organi∣cas, 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 Paren∣chyma, 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 Ge∣neration 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 ob∣served, 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 Spi∣rit) 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 at∣tenuating and subtilizing Aer, may have a more easie and plentiful ad∣mission 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 Kin∣dred, those Plants which have the most, and especially the largest Aer-Vessels; have also the greatest abundance either of a sweet, or of a wi∣ny Liquor. So in Apple; they are larger than in Crab; In Warden, larger than in Qnince; and in Pear-Tree, larger than in Warden. So also in Corin, larger than in Gooseberrey; 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 few∣ness 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, seem∣eth 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 un∣der 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 propor∣tion, 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 separa∣ted, that is to say, filtred, some from others, in very different Propor∣tions 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 Trans∣formation, 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 super∣flous 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 Sepa∣tions 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 Lymphaeducts, 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 incongru∣ous; 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 Re∣sinous 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 Lymphaeducts; 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 Aquae-oleous Liquors of Plants are Milky or white▪ or otherwise Opacous. For the same thing is the cause of the white∣ness 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 Stil∣latitious Oyl of Anise Seeds, is most transparent and limpid, even as Wa∣ter 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 Wa∣ter, 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.a 1.1

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 there∣upon 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 there∣of 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, Ta••camahacca, and divers others, commonly, in our Bils to A∣pothecaries, 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 ei∣ther 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 cut∣ting 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.

Notes

• a 1.1

  See the Discourse of Mixture