CHAP. I.
Of Waters drawn by the cold Still.
The cold Still is much best adapted to draw off the Virtues of Simples, which are valued for their fine Flavour when green, which is subject to be lost in drying. For when we want to extract from Plants a Spirit so light and volatile, as not to subsist in open Air any longer than while the Plant continues in its Growth, it is certainly the best Method to remove the Plant from its native Soil, into some proper Instrument, where, as it dries, these volatile Parts can be collected and preserved. And such an Instrument is what we call the cold Still, where the drying of the Plant or Flower, is only forwarded by a moderate Warmth, and all that rises is collected and preserved.
As the Method of performing the Operation by the cold Still, is the very same, whatever Plant or Flower is used, the following Instance of procuring a Water from Rosemary, will be abundantly sufficient to instruct the young Practitioner in the manner of conducting the Process in all Cases whatever.
Take Rosemary, fresh gathered, in its Perfection, with the Morning Dew upon it, and lay it lightly and unbruised upon the Plate, or Bottom of the Still. Cover the Plate with its conical Head, and apply a Glass Receiver to the Nose of it. Make a small Fire of Charcoal under the Plate, continuing it as long as any Liquor comes over into the Receiver. When nothing more comes over, take off the Still Head, and remove the Plant, putting fresh in its stead, and proceed as before; continue to repeat the Operation successively, till a sufficient Quantity of Water is procured. Let this distilled Water be kept at Rest, in clean Bottles close stopped, for some Days in a cold Place; by this Means it will become limpid, and powerfully impregnated with the Taste and Smell of the Plant.
In this Water are contained the Liquor of Dew, consisting of its own proper Parts, which are not without Difficulty separated from the Plant, and cleave to it even in the drying. This Dew, also, by sticking to the Outside, receives the liquid Parts of the Plant, which being elaborated the Day before, and exhaling in the Night, are hereby detained; so that they concrete together into one external Liquid, which is often viscid, as appears in Manna, Honey, &c. This Water also contains the Fluid, which exhales from the Vessels of the Rosemary, and which principally consists of simple Water, as appears upon long standing in an open Vessel, when the Taste and Odour vanishing, leave an insipid Water behind. Another Part of this Water is that subtile, volatile Substance, which give the Plant its peculiar Taste and Odour; for this the Senses discover in it; but what remains after the Process is finished, scarce afford any thing thereof. The same Water seems also to contain Seeds, or other little Bodies; which in a certain Time usually grows into a kind of thin, whitish Weed, suspended in the middle of the Water; and daily increasing or spreading itself, becomes a Mucilage, which did not appear at first.
I have kept these Waters undisturbed in separate well closed Vessels, and observed that in a Year’s Time, they began to appear thick, which Thickness gradually increased every Year, till at length the Liquor grew ropy and mucilaginous. Hence we see, that this Water contains the elementary Water, and presiding Spirit of the Plant; a Spirit small in Bulk, but rich in Virtues, and exhibiting the specific Smell and Taste of the Subject. This Water, therefore, in exhaling, proves a Vehicle to that Spirit, which contains in a small, subtile, extremely volatile, and thence easily separable Substance, the particular Virtue of the Plant, leaving the Remainder exhausted in this Respect: and hence proceeds the medicinal Virtues of these Waters, which principally depend upon their native Spirit. For this Spirit, in most Plants, having a brisk Mobility, affects the Nerves, and raises the Spirits in case of their Depression.
If the Vessel be close stopped, and set in a cool Place, the Waters drawn by the cold still will retain their Virtues for a Year; but if negligently kept, or any Crack should happen in the Glass, their extremely volatile Spirit secretly flies off, and leaves the Water vapid.
Hence we learn what it is that Plants lose by being dried in the Summer-time; namely, the Water and Spirit we have been describing. Hence we also know the Nature of that Fluid, which first rises from Plants in Distillation, and what that Matter properly is in Plants, that gives their peculiar Odour; that is, their presiding Spirit. Lastly, we hence learn, in some measure at least, what those Effluvia are, which principally in the Summer-Season, and in the open Air, exhale from Vegetables; for it is highly probable, that these constant Exhalations of Plants, especially in the Day-time, have a near Agreement in their peculiar Nature, with the Liquor extracted by the cold Still, though differing in this, that the Exhalation made from the Parts is continually recruited by the Root; whilst by our Operation, those Parts alone are collected, which are driven off from the Plant, after being gathered, and no longer supplied with fresh Nourishment.