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if the stomach, or upper Part of the Guts were pricked, and so much of the Steam in them let out, that there fhould not go fufficient through the lacteal Veffets to force che Blood, or if the Ducts for the Steam of the lacteal Veffels, were stopped or cut, Circulation and Respiration would be that Moment at a stand, and the Air would press the greatest Part of the Blood into the Trunk. Perhaps if the Steam press too hard, the Blood will not fuam ceed in due Proportion. And if the Force of the Steam which drives what they call the Chyle, or indeed which drives itself, were not equals or rather superior, to that Force which drives the blood from the Veins, in the outward Parts to the Heart, the Chyle and Steam could not pass into the Blood. When I name equal Force, I fuppofe, to open the Valves out of the Chyle Duct into the Vena Carva; the Steam by being stopped there, and new Steam fucceeding, muft, though in a lon ger Time, be equal at certain Periods of Time, to the Force of the Blood which resists, and shuts the Valves when it opens them. And as the Steam governs the Motion of the Blood, Nature has contrived the Causes which raise that Ferment which produces it, in fach a man

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ner, that the more the Steam has to do, the more it encreases, and the stronger or Tharper it grows: For as Exercise wastes the Steam, and at the same time requires Supplies of it, and Nourishment in it, it encreases the Fermentation in the Stomach and Guts, which send off those Supplies. If Obstructions in the Vessels, or the Viscousness of the Blood hinder its going off, its Quantity and Heat being pent within, still raises the, Fermentation, and subtilizes or attenuates the Matter, and hinders the Excrements from going off by Stool, till the Steam remove those. Obstructions, * and make the Blood move, or till so much of the sharp Spirits or Salts are freed and raised, as to cụt the Viscousness of the Blood; and as foon as the Steam has free Paffage, the Fermentation by Degrees abates: If the Steam did not successively melt, expand or thin the Blood, by mixing with it in the Arteries, as it returns cooled and thick out of the Veins, no Force whatever could circulate it, nor any crass Matter could ever be secreted out of it.

How

. * And make a brik Circulation. This is the true DoEtrine of incicing and attenuating, for as soon as it has free Passage, &c.

How this Fermentation was at first set forward in created Man, whether this be that Breath of Life breathed into him; or whether those Words meant the Soul ; or what else, I undertake not to determine. But 'tis pot difficult to conceive, how by Degrees, this Fermentation may be set forward in the Stomach of an Infant in the Womb: For allow it be supplied at the Navel, by the Blood of the Mother, something must either pass in dat the Mouth, or be fecreted at the Glands into the Stomach, whereby the Stomach and Guts must be kept distended, or else they would be found lank, and the Case of the Belly straitened or contracted. And if there be 'any Thing issued into the Stomach, that raised into Steam can push the Blood outward, the Compressure of the Womb, will supply the Use of that of the Atmosphere, to return the Blood inward. If Nature has contrived Apertures out of the Blood-Vefsels into the Stomach, 'tis likely they make Secretions into the Stomach, when the Force of the Steam grows weaker there, than the Force of the Pressure of the Atmosphere, whether those Apertures are designed to secrete Matter thither to keep in the Fire, and preserve Life when the Steam is most

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dy fpent, or the Fluids moftly driven out, or to liquate the Meat, and digeft it in Defect of Drink, as the Crops of Birds do to the Corn there, or to secrete Mata ter fo crass or fo fibrous, that cannot be discharged outward, or any other way, or to raise a Fermentation, or to atsist in the Dillolution of the Aliment, or to refund Matter to be farther prepared by leveral Operations in the stomach, till it be fit for nourishing the Parts, supplying the neceffary Juices, or to what other Uses, there and the Secretions made into the several Parts of the Guts are designed, will hereafter be considered.

CHA P. VIII. The Contrivance of the Frame, and Dif

position of the Parts of our Bodies, fita ted for such Motion by those Agents. THE Lungs and Heart, are cased

1 round with an Arch of Bones, on the upper Side, and outwardly; with the Midriff on the lower Side, inwardly; to keep off Cold, or the Preffure of the Atmosphere, which would stop all; if they could either cool or compress then too

much.

much. The stomach and Guts are preffed by the Atmosphere without, and by the Extension of the Lungs, and Depref fion of the Midriff or Diaphragm within, which assists the Force of the Steam, which iffues out of them into the Trunk. And the Arteries which bring the Blood outward, are all defended from the Preffure or Coolnefs of the Air, the great ones within the Trunk, the lefser with Flesh. The Blood mixed with Steam, rúns very thin, and freely in them, because it is not liable to be condensed ; and as they advance to the outward Parts, they are divided and branched smaller and smaller, so that the Blood comes to the Surface through infinitely small, capillarý Vefsels, fo small, that the Strength of the Skin is fufficient to keep off the Pressure and Coolnefs of the Air, and its Pores stop the Blood, and only suffers the Steam to pervade it. When the Steam has done its Office, and the Blood is admitted at such like small Apertures into the Veins, which lie near the Surface of the Body; it will be compressed by the Atmosphere equally in all Parts, which will make the Blood flow that Way, where it meets with least Resistance, which is towards the Heart, because each Aperture of the Val• E4

ves,

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