Dr. Willis's practice of physick being the whole works of that renowned and famous physician wherein most of the diseases belonging to the body of man are treated of, with excellent methods and receipts for the cure of the same : fitted to the meanest capacity by an index for the explaining of all the hard and unusual words and terms of art derived from the Greek, Latine, or other languages for the benefit of the English reader : with forty copper plates.

CHAP. III. What Fermentation is: Its Division as to the Subjects; and first of Mi∣nerals.

FErmentation is an intestine motion of Particles, or the Principles of every Body, either tending to the Perfection of the same Body, or because of its change into another. For the Elementary Particles being stirred up into motion, either of their own ac∣cord or Nature, or occasionally, do wonderfully move themselves, and are moved; do lay hold of, and obvolve one another: the subtil and more active, unfold themselves on every side, and endeavour to fly away; which notwithstanding being intangled, by others more thick, are de∣tained in their flying away. Again, the more thick themselves, are very much brought under by the endeavour and Expansion of the more Subtil, and are attenuated, until each of them be∣ing brought to their height and exaltations, they either frame the due perfection in the subject, or compleat the Alterations and Mutations designed by Nature.

Fermentation is an action or motion meerly Natural, and what doth perform it, are only Particles Naturally implanted in the Concrete; yet as to the subjects in which they are found, it is wont to be variously distinguished. And either things of Nature are said to Ferment in a threefold Family, of Minerals, Vegetables and Animals; or the Works of Art, to wit, when Actives are applyed to Passives by an outward Agent. Though the Term and Consideration of Fermentation, are chiefly due to Artificial things, and things made by Hand; yet it will not be from the purpose, to speak first something of Natural Things, that a Comparison be∣ing made of either, the Truth of our Hypothesis, and the certainty of the Principles may be confirmed. But this only lightly by the way, in this place I shall pass over, because their more full handling belongs to Physiology, or the Discourse of Natural or Physical Things.

In the first place, as to Minerals, altho in the bowels of the Earth, the Fermentation is less conspicuous than in the Superficies, yet it easily appears that the Elementary Particles, or the Fer∣mentative Principles, are included in the depth of the Earth, as in a certain pregnant Womb: which there constitute Concretes, and things gathered together, by strict Embraces, the Pro∣ductions of Minerals; but being loosned, and moved in the Bosom of the Earth, or exhaled up∣wards, cause the appearances of Meteors.

First, The Generation of the more hard Minerals, induces rather Congelation than Fermenta∣tion; because indeed these Principles, growing together in every Subject, are so fixed, and as it were bound together inBonds, that they are not able any wayes to move themselves, or to de∣part one from another. This kind of fixation chiefly depends on the plenty and greater pro∣portion of Salt and Earth (sometimes with an addition of sulphur) than there is of spirit or water, to wit, salt and earth, being most smally broken, and resolved even into a Vapour, lay hold of one another, and stiffen into a hard matter, and at last not to be loosned; almost after the same manner as making of Glass, and the burning of Bricks and Earthen Ware, are per∣formed. For Glass consists of Salt and Earth, which when broken into most small bits, by a very intense Fire, they suffer a flux, they mutually lay hold of one another, and so strictly and intimately come together, that they are never to be parted. Glass is more fragil, or easy to be broken, then Earthen Pots, or Minerals, because it has a greater plenty of Salt, than of Earth, which is more plentiful in Earthen Ware, and in Minerals: To some of which, also happens a modicum of Sulphur, and for that reason they are more tenacious and ductil; as is to be observed in Metals, when in the mean time stones, and what contain little of Sulphur, are fragil, and apt by every stroke to fly to peices. In Vitrification there is need of a violent Fire, for the fusion of the Salt and the Earth (whose Particles, as is commonly said, are the Pestles of the Chymists) but within the Bowels of the Earth, there is not required such a fufion of Fire for the Con cretion of Minerals, because Salt and Sulphur exist, being naturally resolved into most simple Particles; which, when they lay hold on the Earth, easily stiffen into Metal, or into a stony hardness. There are some Fountains found out, which, for that they flow with a primitive Salt, and resolved into small Particles, whatever Bodies are immersed therein, they cause them presently to be∣come stony. We have read also, of Men changed into Stones, yea a whole City to have been stiffenedinto a stony substance, by the Air, or by some Vapour, brought forth of the Earth: The Faith of which thing is left to the Authors.

Meteors are made out of the same Principles by which Minerals are made, and conceived almost in the same Womb: but loosned from Concretion wandring here and there, and diversly fluctua∣ting: or which being included in Subterraneous Vaults, and there moved, produce divers Spring∣ings up of Fountains, or ebullitions ofhot Vapours; or exhaling from the Dens of the Earth, and being mixt with Airy little Bodies, they cause within the Region of the Atmo-Sphear, as it were a diverse fashioned Landskip, of Clouds, Winds, and the appearances of other things, in the Superficies of the Earth, or on high: in either there are highly active Principles chiefly Salt and Sulphur. Spirits are either deficient in Meteors, even as in Minerals, or are found only in a very small quantity or proportion: to wit, they are almost wholly excluded from these, by reason of the strict frame of the subject, which doth not easily yeild space and passage for their motion; also they abstain from those (viz. Meteors) by reason of the lax, and wholly loose structure of Matter, from whence they, who are mighty in swiftness, easily break forth, and de∣sire to fly away.

Within the Bosom of the Earth, the Saline Particles being loosned, even into a Vapour, and then kneaded with an Earthy Matter or the moistening of Waters, they cause Eruptions of Foun∣tains, and Acidulous or Spaw Waters, which resemble the disposition of Vitriol, Alum, Nitre, sometimes of Iron or Copper. Also the Sulphureous little Bodies being loosned, and gathered together, enkindle an Heat, and sometimes Subterraneous Fires; by whose Breaths the Dens and Caverns being made Hot, like an Hot-House, whilst the Watery humours pass through them, they from thence conceive their Heat, and supply the Springs of Hot Fountains for Bathes.

In like manner, in this visible and Ethereal World, Vapors both sulphureous and saline, and of a diverse Kind and Nature, perpetually breath forth, and are diffused through the whole Region of Air. From hence the diversity of Winds, the vicissitudes of Cold and Heat, Rain, Snow, Hail, Dew, and hoar Frost, and what are of this Nature, have their Origine. Con∣cerning the particular Instances of these, the famous Gassendus may be consulted; who, in his Epicurean Philosophy, most aptly deduces the Phaenomena, almost of all Meteors, and the Rea∣sons of them, from the Exhalations of Sulphur and Salts, either Nitrous, Vitriolick, Alumi∣nous or Almoniack.