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cipitate of their own accord, but oftener by the Asistance of some other Liquor added to the Menstruum. As Bodies can't be sustain'd, till they are render'd specifically lighter than tbe Menstruum in which they are diffolv’d, so, on the

contrary, if any Menstruum be made lighter than the said dissolv'd Particles, 'ris plain they can't be sustain'd or suspended any longer, but must fall to the Bottom. This is the Reason of Precipitation, and is effected two ways, viz. by dropping into the Menstruum a Liquor specifically lighter or beavier ; the first renders the Menstruum lighter than before, and therefore unable any longer to suspend the diffolvid Body, and the heavier Liquor, what with the Weight of its Particles, and the Impetus they acquire in their De. scent, carry down and sink all the solid Particles they meet with in their way. In the first Cafe, the Spirit of Sal Ammoniac will plentifully precipitate the Filings of Mecals dissolv'd in acid MenPruums; and in the latter, Water alone will precipitate Tinctures of Vegetables extracted by

Spirit of Wine. Cokobation. COHOBATION is a Sort of repeated

Distillation, or such wherein the Liquor fint drawn off, is (instead of fresh Water, &c.) again return'd upon the Subject to be drawn of a second Time, which is again cohobated, or pour’d on the Subject in the Still, and so is con. tinued or repeated several Times ; the Intention of which is to open and separate mix'd Bodies, to extract their Virtues more essentially, to voPowder, by evaporating the Mercury. No Iron or Copper can by any means be amalgamated.

latilize Spirits, &c. Amalgama- AMALGAMATION is a Process emtion.

ploy'd about Mecals, and consists in mixing Mercury with them when fused or melted, in or der to fit them to be extended on some Works, as Gold ; or else to reduce it to a very subcil

Powder,

THE INSTRUMENTS used in Chemistry are Of Chemical of three several Kinds, viz.

Instruments. First, the ELEMENTS; as (1.) Fire, on Elements. whose Agency all the Art depends, for 'tis by Fire the Particles of Bodies are forced apart, and put into Motion ; as in Distillation, Sublimation, Fusion of Metals, &c. (2.) Water, whose Use is general and well known in Chemical Operations. (3.) Air ; this is consider'd by Chemists as an almost universal Diffolvent, and as such properly belongs to the next Head. (4.) Earth, which is of various and frequent Use in this Art; as in Lutings, Sand- Heats, &c.

SECONDLY, MENSTRUUMS ; which are any Menftruums. Kind of Dissolvents, or Liquids, which by steeping or digesting Bodies in them, do by Degrees diffolve or disunite the Particles of those Bodies, and so change them from a solid to a fluid State. And of this Sort of Instruments are Air, Water, Spirit, Mercury, and various others both Natural and Chemical Preparations, especially of the Acid Tribe.

THIRDLY, VESSELS or Utensils of divers Utensils. Sorts; as Furnaces of several Forms and Kinds, Alembics and Stills, Retorts, Receivers, Cucurbits, Matrasses, Crucibles, Lingots, Coppels, Aludels, Cranes, &c. all which to describe here would answer but little Purpose ; since a just Idea of their Forms and Uses is only to be obtain'd either by large Prints, or an actual View of them in the Laboratories of the Chemists.

of

523

OF PHYSIC; or the Theory of

MEDICINE and DISEASE S.

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EDICINE, or, as it is com- MEDICINE
monly callid, PHYSIC, con- or Physic
lists in the Knowledge of those defined.
Things, by the Application of
which the Health of Bodies is

preserved or restored, by removing Diseases. The Object therefore of Medicine Its Object. is the Life, Health, Disease, and Death of Mankind ; the Causes whence they arise, and the Means by which they are governed.

THIS Art is divided into five great Parts, Medicine viz. (1.) Physiology, in a strict Sense so calld, divided into which respects the Nature of the Human Body: five Parts ; (2.) Pathology, or the Doctrine of Diseases. Pathology, (3.) Semeiotics, which relates to the Signs and In- Semeiotics, dications of Diseases. (4.) Hygieina, or that which Hygieina, prescribes Rules for the Conseryation of Life and Health. (5.) Therapeutics, which treats of the

Therapeutics. Materia Medica, and Cure of Diseases.

PHYSIOLOGY, the first and most philo- of Physiology, sophical Part of Medicine, explicates (1.) The and that it Nature, Structure, and Parts of the Human

teacbes. Body, with their Use in the whole Animal Oeconomy. (2.) What Life is, and wherein it doth consist. (3.) What the true Notion of Sanity or Health is : And, (4.) The various Effects of Life and Health, or a good State of the Animal Conftitution : All which Particulars are call'd the Res Naturales, or Things according to Nature,

THE

The Animal The StruElure or Constitution of the Human Structure and Body, and the Use of the Parts in its Oeconomy, Oeconomy.

hath been already explain'd in the Chapter of

Anatomy, and is thence to be learn'd. Life, what.

LIFE is said to be that Condition of an Arimal Body, which, both with respect to the schod and fluid Parts, is absolutely requisite, that there might subsist a mutual Union and Commerce between the Body and Mind, in some certain Manner; or which, when impair'd, may be fonje how restor'd without necessarily destroying the

same. Health, HEALTH or Sanity is that Affection of

Life which arises from that due Structure, Conformation, Temperament, and Oeconomy of an Animal Body, whereby all the Parts thereof are in a proper Condition to exert all their Natural Actions and Fun£tions of Life, with a requisite Degree of Facility, Delight, and Constancy.' Or, Health is a right Exercise of the Actions of the Solids and Fluids according to the Laws of Nature, whereby the Circulation of the Blood is

maintained thro' the minutest Arteries without Whence it Obstruction. And this Disposition of the Paris, proceeds. and the Justness of their Actions, which is the

Foundation of Health, proceeds from, or is the Effeet of what is callid the Equilibrium Naturæ, or Balance of Nature; which is defined to be that equal Temperature of the Solids and Fluids wherein the Blood is capable of circulating freely; the feveral Secretions are made therefrom in the exacteft Proportions, and the Excrements excern'd, by all the different Emunétories, without the least Ob

struction. The Balance

THIS BALANCE of NATURE itself of Nature,

arises from that proper Tone, Tensity, Springines, or Contractile Power of the Fibres of the Solids, as effects a due Circulation, Liquidity, and requisite

Secretiones

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