ves, or Puth of the Steam through the Heart, makes a fort of Vacuum; and the Veins are wideft that Way, and there is lefs Preffure upon the Veins in the Trunk, and perhaps there may remain some small Force of the Motion, by Pushes outward from the Heart beyond the ReSee p. 51. turns, to further it that WayThe Veffels in the higheft Part or Head, whither the finest of the Steam, and the pureft of the Blood, most naturally tend, and where it would in any violent Emiffion, be in most Danger of bursting the capillary Veffels, and where Nature employs the Steam the most, all the Senfes being feated there, are environed with a Cafe of Bone, to keep off the Preffure of the Atmosphere, and prevent thofe Veffels burfting outward, to prevent the Steam from perfpiring, and fecrete it for its proper Ufes into the Nerves; and thofe Nerves are continued along the inward Parts, and branched out as the Arteries are, where -the Preffure of the Air cannot hinder the Steam from paffing the Nerves, whether they be Tubes, or porous by compreffing them, or condenfing the Steam till it has extended the Muscles, or be perspired at the Organs of Senfe, or Pores of the Nerves. When the Steam arifes in too

great

great Quantity thither, or perhaps when 'tis too fubtile, fo that too much of it fecretes there, all our Senfes are at a Stop, or disordered. * The two great Difcharges are downward, and within the Body, fo that the Air by its Preffure or Coolness can condenfe the Steam, but not hinder its Operation. The Sides of the Trunk of the Body, are compreffed, or fqueezed by the Air without, and the Steam in the Stomach, Guts, &c. within. And as the Air prevails, the Steam is preffed into lefs space, the Parts contracted, and the Juices are preffed inward as the Steam prevails, it expands, the Vieffels are extended, and the Juices are preffed outward. Every Part or Member of the Body, confifting of Bone environed with Flesh, and Skin, compofed of Arteries, Veins, hollow Tubes, is preffed by the Air without against the Bone, and by the Steam in the Arteries, Veins and Tubes, as it circulates the Blood and Juices, by its expanfive Force, or fideways Motion against the Bone inward, and against the Air outward. The Infides

of

*Perfpiration which is generally looked upon as the moft confiderable Difcharge, is by our Author all along understood by the Evacuation of the overplus Steam, and then there are only the two great Difcharges remaining.

of the Trunk, and Outfides of the Sto mach, Guts, Liver, Milt, Kidneys, Midriff, Caul, Mefentery, and Bladder, &c. are compreffed one againft another, by the Steam within and Air without; and their Out-Coats are fo clofe, that in healthy Perfons they either emit nothing, or what one emits, others admit. When the Steam extends the Stomach and Guts in all Parts, little is returned into any of them. But when the Steam in any Part between ftop and ftop, or Valve and Valve is wafted, the Valves fhut, the Part contracts, and the Steam iffues from the other Parts; Juices are preffed by the Air and Steam, into the Glands in that Part, to be ready to iffue into it to begin a new Ferment, or, &c. That the inward Parts always fill the Cavities of the upper and lower Divifion in the Trunk, and prefs against one another, with as great, or a greater Preffure, than that of the Air, is evident; for confidering how pliable or flexible the Guts full of Fluids and Steam are, when there is a fmall Aperture made in the Cafe or Rind of the lower Belly, they could not push out, if there were any Space void within, and if that which expands them were not

1

stronger

.

fronger than the Preffure of the Air: And when the Lungs expand, prefs the This is Guts, and by them extend the Rind of evident in all Rupthe Belly, if there were any void Space they would prefs into it, before they could ftretch the lower Belly against the Strength of its Mufcles, and the Preffure of the Air. Nor could the Preffure of the Air upon the lower Belly, prefs back the Lungs into their firft Space, fo long as there were any fpace empty in the lower Divifion, and the Steam has the like expanfive Force in Proportion to its Quantity, in every Artery or Tube in the Body; fo that every one, ftrong or weak, is fupported by the others next adjoining, from extending out of Course, or burfting. If more Ribs, or a Cafe or Frame of Bones, had included or environ ed the lower Belly, the Circulation of the Blood, and the Vibration of the Lungs, could neither of them have been performed, for the Steam must continually have been fo strong, as to have kept the Place allowed it, in the Cafe full, and preffed the rest with Force equal to the Preffure of the Air, and its own expanfive Force, that is, fo much above the common Pref fure or Refiftance of the Air upon the Blood-Veffels, as fhould have been fuffi

cient

cient to have overcome that Force, and have circulated the Blood, which would have prevented any Blood from entering into the Intestines, and then the Stomach and Guts could not have been moved by the Lungs, nor have emptied and dif charged the Excrements, nor could the Lungs have had Liberty to vibrate in. But by the Pliablenefs of the lower Belly, the Lungs play, and the Stomach and Guts are moved, and kept compreffed clofe, according to the different Extents of the Steam. And the Preffure, the Air has at each Time, lies equally upon the Stomach and Guts, to affift in driving the Steam, as lies upon the Blood Veffels to obftruct its Circulation, and the expanfive Force of the Steam cafts the balance, and moves the Blood fafter or flower, in Proportion to the Difference of its Strength, &c.

There is a twofold Force, or two Forces joined, which act in driving and preffing the Steam out of the Stomach and Guts, and but one of those Forces in obftructing it, and the Blood, which it drives; and that much leffened by the expansive Power of the Steam in the Arteries and Veins, whereby the Blood is not only thinned, but thofe Veffels or

Pipes