The anatomy of plants

HE next general Inquiry, proposed to be made, was this, After what manner the Colours of Plants shew themselves, upon their infusion into Liquors. The Liquors I made use of for this purpose, were three, sc. Oyl of Olives, Water, and Spirit of Wine. The Water I used was from the Thames, because I could not procure any clear Rain Water, and had not leasure at present to distill any. But next to this, that yields as little Salt, as any.

2. §. As for Oyl, it is known, that most Plants either by Coction or long Infusion, will give it their Green Colour. I have likewise tryed some Yellows, and find they will do indifferently well; as Saffron, which, by Infusion in Oyl, gives it a light golden Tincture.

3. §. Divers Aromatick Plants, as Mint, Majorane, &c. being dryed and infused in Oyl give it a double Tincture, both green and yellow; one drop of the Oyl shewing green; but a good quantity of it held up against a candle looketh redish or of a deep yellow.

4. §. But there is no Vegetable yet known which gives a true Red to Oyl, except Alkanet Root: with which, some colouring either common or other Oyl, vend it under the name of the Red Oyl of Scorpions.

5. §. These things confirm what we have said concerning the Causes of Colours in the Leavs and Flowers of Plants, upon this twofold Consideration. Discourse of Mixture Ch. 5. Inst. 2. §. 3. & Inst. 5. First, that Oyl is the most proper Menstruum of Sulphur. Secondly, that Oyls have a greater congruity with Acids than with Alkalies; as I have formerly shewed.

6. §. I say therefore, that in Blews, Purples and especially Reds, the predominant Principles being Sulphur and Acid, the Oyl either abstracts the Sulphur of it self, or at least, unlocks it from the Acid Parts; whereby both of them are bestowed seperately to their like parts in the Oyl; upon which their disunion the Colour vanishes: that depending, not upon either of them alone, which of themselves are Colourless, but upon both united together.

7. §. On the contrary, a Green Colour not depending on a predominant Acid, but an Alkaly, or some Saline Principle different from an Acid; this will not so easiely be imbibed separately, into the Pores of the Oyl, but only by mediation of their Sulphur. So that being both imbibed without any disunion, they still retein the same green Colour they had before in the Plant.

8. §. Hence also it is, that red Roses being dryed and infused some time in Oyl of Anise Seeds, a more potent Menstruum than Common Oyl; they wholly lose their own Colour, and turn white; the Oyl remaining Limpid, as at the first. That is the Sulphur or that part of it on which cheifly the Red depended, is absorbed separately by the Oyl, and so the Colour vanishes.

9. §. A SECOND Menstruum I made use of, was Water. And First, Alkanet Root, which immediately tinctures Oyl with a deeper Red, will not colour Water in the least.

10. §. Next it is observable, That Water will take all the Colours of Plants in Infusion except a Green. So that as no Plant will by Infusion give a perfect Blew to Oyl; so their is none, that I know of, which, by Infusion will give a perfect Green to Water.

11. §. But although the Green Leavs will not give their visible Colour, by Infusion in Water; yet they will give most other Colours, as well as the Flowers themselves. So the Green Leavs of Cinquefoyl, give a Tincture no higher than to resemble Rhenish Wine; those of Hyssop, Canary; of Strawberrey, Malaga; of Mint, Muscadine; of Wood-Sorrel, Water and some drops of Claret; of Blood-wort, Water and a dash of Claret; and those of Bawm make a Tincture near as red as ordinary Claret alone. All Aromatick hot Plants, give a yellow-red Tincture, or colorem ex luteo rubrum. All Plants with a yellow Flower give either a pale citrine or yellowish Tincture; and the like. Yet all give not their Tincture in the same space of time; some requiring a fortnight, others a week, others five, three or two days, and some but one, or half a day. From hence it appears, that the Colours of most Flowers are begun in the Leavs; only Green being therein the predominant Colour, as a veil spred over them, conceils all the rest. But passing on into the Flower, where the Aer-Vessels, as is aforesaid, are under the dominion of the Lymphæducts; they show themselves distinctly.

12. §. A THIRD and the last Menstruum I made use of, was Spirit of Wine. And here it is to be remarqued; That as Oyl rarely takes a Red, there being but one known Instance of it; nor Water, a Green: So neither Spirit of Wine, a Blew. I have tryed with several blew Flowers, as of Lark-heel, Violet, Mallows, Burrage, and others, whereof it will not take the least Tincture.

13. §. Again though no Blew Flowers, that I know of, will give a Blew Tincture to Spirit of Wine: yet having been for some days infused in the said Spirit, and the Spirit still remaining in a manner Limpid, and void of the least Ray of Blew; if you drop into it a little Spirit of Sulphur, it is somewhat surprizing to see, that it immediately strikes it into a full Red, as if it had been Blew before: and so, if you drop Spirit of Sal Armoniac or other Alkaly upon it, it presently strikes it Green. Which further confirms what have been before said of the Causes of Vegetable Colours.

14. §. It is also observable, That the Green Leaves of Bawm, which give a Muscadine Red, with some Rays of Claret, to Water, gives a pure and perfect Green to Spirit of Wine: and is the only Plant of all that I have yet tryed, which doth the like.

15. §. It is likewise to be noted, That both Yellow and Red Flowers give a stronger and fuller Tincture to Water, than to Spirit of Wine; as in the Tinctures of Cowslip, Poppys, Clove-July-Flowers and Roses, made both in Water and Spirit of Wine, and compared together, is easily seen. So that for Tinctures made with Flowers, whether for Medicines, or other purposes, Water, with respect to the Colour, is the better Menstruum. I say for Tinctures made with Flowers; for there are some other Parts, especially Gumms, as Gamboja, Myrrh and Aloes, which give their Tinctures full and clear, only to Spirit of Wine. Some of which are used by Leather-Gilders, and others, for the washing over of Silver, so as to give it the Colour of Gold. Thus far of the Colours of Plants as they appear upon Infusion.