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The following Obfervations and Deductions, induce me to believe, that those two Agents are of that Force, which is ne-ceffary to circulate the Blood, and that thofe Agents employ their Force to perform that Operation.

T

pable of

them; and

HE Force of Steam, every one The two knows, is in Proportion to its Ra-Agents carefaction or Expanfion, and if it were the Powers proved how far each fpoonful of Liquor afcribed to with a little Air, may be expanded by that they that Degree of Fermentation and Heat, are the real which is in an healthful Body, it would ones. feem prodigious, and the Agent, not infufficient for the Task affigned. The Force of the Preffure of the Atmosphere is fufficiently proved, and its Strength is certainly known, and I hope it will be allowed fufficient for the Tafk I affign it, if it appear, it employs its Force there

in.

'Tis evident, that such a Mixture of Solids and Fluids, as is conftantly fupplied into our Stomachs, kept warm, and defended from the Air, as that in our sto

machs

1

machs and Guts is, and kept in Agita tion, as that is by the Motion of the Lungs, Body, &c. would ferment and raife an hot Steam, extend the Veffel that contained it, or if there were long fmall Paffages, iffue out along them, till condenfed by the Cold. Even the Excrements after they are difcharged, ferment in the Dunghill, grow hot, and fend out a ftrong Steam vifible to the Eye in cool Weather. That the Steam raifed in the. Stomach and Guts has no other Way to pafs, except when it breaks upward or downward, but through the lacteal Veffels, and along with the Blood, by the Vent at the Lungs, out at the Pores, or, that which condenfes, at the Ureters, is alfo evident.

That the Matter, which paffes from the Guts into the Blood, paffes in Hali tus or Steam, is vifible by the Straightnefs of the Paffages through which it goes. That it paffes with the Force affigned, is alfo demonftrable: For, it could neither pass through ftraight Paffages, nor enter into the Blood, if its Force were not greater than that which drives the Blood thro' the Veins, towards the Heart; Otherwise that Force would drive the Blood and the Steam back through the

lacteal

lacteal Veffels into the Guts. If the

outward, the prefs upon it Force which

Heart pumped the Blood
Air muft bring it back, or
in returning. Hence the
makes the Chyle or Steam enter into the
Blood, muft be greater than the Preffure
of the Air. If the Matter which paffes
the lacteal Veffels were more crude, or in
larger Particles, it could not pafs the ca-
pillary Veffels, nor circulate in the Blood,
but would cause Stoppages and Swellings
there. If they were much smaller, they
would all go out at the Pores,

Steam defended from the Cold, confined, and fucceffively impelled and augmented with new Supplies, will rife to a prodigious Force. But where that which confines it will be opened with a certain Force, and give it Vent, it can never rise to be much stronger than that Force. I mean the Steam which iffues with the Chyle, through the lacteal Veffels, in a fecond of Time, is fufficient to open the Valves of the Heart, push about the Blood, and fhift a certain Proportion in→ to the Veffels compreffed by the Atmofphere. And a Stop in the lacteal Veffels for a fecond of Time, would expand the Stomach and Guts, notwithstanding the Resistance

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Resistance of the Air, Mufcles of the
Belly, &c.
i

Steam that both expands the Parts, drives the Blood, and iffues out at the Pores, must be ftronger than the Air, though the expanfive or fide-ways Motion, feems not to be much stronger, yet if a Pipe with a Fluid in the Middle, and each End empty, and the fides too strong to be compreffed by the outward Air, were to have an Aperture of equal Dimension at each End, and one End fixed in a Veffel which would emit Steam in the fame Quantity, and with the fame Force as the Guts, and the Air were let in at the oppofite Aperture both at the fame Time, the Air would push in with great Force, and 'tis likely prevail against the Steam, and push the Fluid forward: But the Steam ftopped, and not condenfed, would augment its Force as more Supply iffued, and prevail. And as the Preflure of the Air would not encrease, the Steam would drive it and the Fluid, out at the Aperture where the Air came The Air in. The Air is not any way fit for Cirnot a fit culation, because it would not wafte, nor Agent to circulate condenfe, nor iffue at the Pores, against the Blood. its own Preffure; fo after the Fluid were once pushed, the Pipe would be filled

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with

1

could not

with Fluid and Air, and would stand still, the outward and inward Force being equal. Nor would the Air mix with the Fluid, and go along with it as Steam does, but the fore-end would be full of the Fluid, and the hinder-end full of Air. If the Agents that move the Blood, The Blood did not go along with the Blood, and were not extended all over the Body, there must be one Part, fuppofe the Agents Heart, of fufficient Strength to move all the Blood in the Body, and the Heart it. must move of itself, or be moved by fome ftronger Agent. If feveral Parts acted jointly, the Cafe would be the fame.

move with

out the

going a

long with

Preffure of

the At

I think the expanfive Force of the The Steam Steam within a Man in perfect Health, in a healis nearly equal to, but fomething stronger thy Man stronger than the Preffure of the Atmosphere in than the fair, clear Weather; because he is not the fenfible in any Part of the Preffure of the mosphere. Atmosphere. I know the Reafon commonly affigned is, because it preffes equally on all the outward Parts; but that will appear not fufficient; for if there were not a Refiftance within, it would comprefs our Bellies clofe up to our Backs, till the Strength of the Mufcles could stop it, or till no Space remained, but what were filled with Fluids or Solids, and it

would

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