CHAP. I. The motion of the Blood from the Heart by the Arteries to the Extremities of the Body, and from the Extremities by the Veins a­gain to the Heart, is asserted by Experiments.

THat I might try whether the Blood flowed by the Arte­ries, I tyed strait with a thread the Artery sometime of the fore-foot, sometime of the hind-foot, some­time the Carotidals, lest any thing should escape me, in a living Dog. [Page 47]The Artery in a short time beyond the Ligature, viz. towards the Ex­tremities of the Body, falling, and rising on this side; I mean betwixt it and the Heart, by reason of the obstructed stream, doth teach that the Blood is carried from the Heart by the Arteries unto the Extremities of the Body.

But lest (Reader) thou shouldst accuse my inference of Lightness, the Artery being cloven beyond the Ligature, yea to take away thy cavelling, being quite cut off, did scarcely stain the wound with Blood; when being opened on this side the Ligature, it burst forth in a spring of Blood.

Having examined the Arteries, I resolved to view the course of the Blood in the Vena cava: This be­ing freed from its Teguments, I bound it in the same place, still re­serving its Fellow-Artery free: But with a success directly con­trary to the other; for on this side the band towards the Heart it fell, and rose beyond the Ligature to­wards [Page 48]the Extremities of the Body: Then being wounded in that place that was flaccid, it emitted no Blood; but being opened where it was dilated, it threw forth more Blood than the whole capacity of the skin of the thigh and leg should contain: Therefore, say I, as the Blood from the Heart is spread a­broad by the Arteries, so being re­turned by the branches of the Veins into the Vena cava, 'tis again ga­thered into the Ventricles of the Heart it self.

But lest any should doubt that the Blood which springeth out of the Veins hath not flowed into them from their Fellow-Arteries, I opened the Crural vein where it most appeared; the Blood swiftly sprung from it: then I tyed it's Fellow-Artery, and which is won­derful! the force being abated, the Blood of the Vein distilled by drops first, and at last quire stopped: But the freedome of the loosed Ar­tery renewed its stream; and the Blood issuing out of the Vein with [Page 49]former vigour shew what commerce the Arteries have with the Veins.

Neither [Reader] let it trouble thee, that sometimes, though sel­dome, Blood springeth from the Vein on this side the bandage where the Veins are then most fallen. Believe me, not affirming but as one that hath tryed, that the dispersed twigs do disburthen themselves of this Blood so discharged into the Vena cava.

One day (as I have said) I was at work, and wounded on both sides the Ligature of the tyed Vein, behold not onely beyond, but on this side the Ligature I wondred to see unceasable springing of the Blood. I then did separate the Vena cava from her coverings upwards, even to the division of the Iliack Branches, and I bound all the Branches of the Veins I met with in my passage straitly, the Blood stopp'd: Then indeed on this side the Ligature the Blood evanish'd, and was exhaust from that place up to the Valve that lurketh in [Page 50]the Groin, its Clack stopping al­together the descent of the Blood which pressed it, shew clearly that the Blood had no power to descend by the Veins.

Then concluded I, If the Blood be onely spread by the Arteries, a member, the Artery being tyed, may be amputed without blood­shed. Sooner then I had said it I tyed the Crural Artery, leaving the Veins loose, and at the ham a little below the bandage I cut off his leg: some drops of Blood in­deed did flow from it, viz. such as the last Valves of the cut-asunder Veins did not contain, and with which the twigs of the Arteries dispersed up and down the skin for the nourishment thereof were fil­led. But when the Cut-veins are emptied of that Blood which is be­neath the Valves, and the small Branches of the Cutaneous Arteries are stopp'd, partly by the congeal­ing occurse of Cold repressing the Heat, partly by the contraction of the grieved parts through the [Page 51]wound, the flowing of the Blood did altogether cease; neither did any more Blood spring from any of the dispersed Vessels spread over the whole amputation, till way was made for the Arterial Blood by un­tying the Crural Artery.

I tried the same in the Axillar, in the Jugular: but because 'tis more troublesome in a Dog by rea­son of his short neck, in a Goose the Experiment did easily succed.

And lest you should deny that in a man which is demonstrable in a brute, pray you look upon your Arm, if leanness perchance suffer the full Veins to appear; there if you rub downward with your fin­ger, it then swelleth most, you will wonder to see the knotting of the Shut-Valves, and from them down­ward to the pressure of the finger the Canal of the Vein empty. Look to a Chirurgion ebrathing a Vein, he binding straitly a Ligature about the brawn of the Arm, stop­peth the flowing of the Blood from the hand to the heart: He looseth [Page 52]a little the Blood-band, being to hard tyed, that the Artery being freed from the straitness of the com­pressed Muscle of the Arm may re­fresh the choked Veins with a fresh stream of Blood.

Neither imagine thou that I have but once made Trial of the Cir­culation of the Blood in the greater Vessels of the Veins and Arteries. Indeed having tried this every where, yea in the smallest Branches of both, as my sight would serve, I found it every where the same. This was shewn by Ligatures in the hands and feet: This both the breathing and Valves of each Vein, yea those in the finger, did demon­strate.

CHAP. II. The Vena porta doth discharge it self by the Liver into the Vena cava of the Blood it receives from the Coeliack Artery; and hence the Gallant Harvey's Opinion is confirm'd.

HAving manifested the Cir­culation of the Blood from the Heart by the Arteries unto the Extremities of the body, and from thence by the Veins hi­ther again, I resolved to know how this holds in the Vena prrta.

Having tyed the Branches of the Coeliack Arteries, where the Blood enters the Mesentery, they fell and rose after no different manner from the rest, viz. swelling from the Trunk to the bandage, and be­coming flaccid betwixt the Liga­ture and Intestines.

I oft-times tyed the Meseraick-port-veins, yet nevertheless they filled betwixt the Intestines and Ligatures, and did altogether fall [Page 54]betwixt the Ligature and Liver; yea being opened on both sides the Ligature, the Blood issued out. I tried the Veins of the Spleen with the same success; also that Vein which is called Vas breve, betwixt the Stomack and Ligature in the middle thereof full; but betwixt it and the Spleen it seemed to wain, notwithstanding being opened on both sides, the Blood followed.

From these I inferr [except you please to admit frequent Synana­stomosies betwixt the Branches of the Port-vein and their Fellow-Arteries] that the Blood is either stopp'd by none, or at least very small Valves within the Branches of that Vein.

The opinion of Riolan presently came into my mind, viz. That the Blood of the Vein-port doth not at all pass into the Vena cava. And the Authority of so famous a man had altogether stopp'd my fur­ther search, if my eyes, which I appointed strict Judges of the game, had not withstood it, reproaching [Page 55]my laziness that fail'd in the midst of the course.

Therefore being more troubled, I had my recourse to the Trunk of the Vena porta, and I bound with a Ligature the Mesenterick branch three fingers broad from the Liver: At the same distance I bound the Splenetick; the knot indeed was strait, but easy to be loosed. Scarce had I left off binding, when behold the Pipe betwixt the Ligature and Liver which before rose Turgid, was now a bloodless Chanel, and became flaccid, on the other side the Pipes of both the Branches were filled with an indifferent stream of Blood flowing from the Intestins and Mesentery, yea from the Sto­mack and Spleen also.

I fill'd again the emptied trunk of the Vena porta, by untying one of the Ligatures; which being pre­sently again tyed, next the Liver, it was emptied. The Experiment be­ing frequently reiterated, it was evident that the Blood flow'd abun­dantly and swiftly out of the Vena [Page 56]porta into the Windings of the Li­ver. And perceiving that through the Concavity of the Liver the Vena porta did divide it self in many Branchings for the conveyance of Blood after the manner of Arteries: Whether [say I] doth not the Vena porta it self, instead of an Artery, thrust out into the Liver, an abun­dance of fervid Blood for the che­rishing of the stomack and con­cocting faculty? The smalness of the Coeliack Branches being alto­gether, as I thought, unable for so great an effect.

And rightly I thought it; for the Vena porta within the Liver is altogether an Artery: For as the Arteries issue their Blood from out their Trunk into their Branches, but the Veins return it from their Branches into the Trunk: So the Vena porta from its Trunk distri­buteth Blood to its furthest Branches that are within the Liver, which Blood it hath gathered into its Trunk from the Branches it hath without the Concavity of the same. [Page 57]And as the Coats of the Arteries are thicker than those of the Veins, so the Vena porta hath a thicker skin within the Liver than it hath in its Vessels without the same.

Neither believe that I depart from ocular inspection when I say that the Coat of the Vena porta is thicker within the Liver; for I broke in pieces at leisure all the substance of the Liver of the Beast which I anatomiz'd, and laid open the form of the uncloath'd Vena porta: The Tunicle whereof with­out the Liver retain'd the thinness of a Vein, but within the Liver did altogether appear to be an Artery: So that it did undoubtedly appear which before I did suspect, That some of the Vessels of the Blood, as the Aorta, deserve onely the name of Arteries; Others admit onely the name of Veins, as the Vena cava; And to conclude, some are appointed by Nature for both du­ties, such as we have found the Vena porta to be.

But when I doubted whither so [Page 58]great a current of Blood flowed, and believing it had its course unto the Vena cava, I tyed [I will not say with the Antients the Trunk, but] the branch thereof where it entreth the gibbosity of the Liver, as far from the Liver as I could; and then the Blood rushing to the bandage [the branch greatly rising betwixt the Ligature and Liver] shewed the manifest commerce be­twixt the Vena porta and the Vena cava; and how appositly the Learn­edst English Physician, Will: Har­vey, held the motion of the whole Blood to be Circular.

CHAP. III. That the Blood floweth out of the Right Ventricle of the Heart through the Lungs into the Left Ventricle.

THis one thing did remain to perfect so great a Circulation, to know fully the Passage of the Blood from the Veins through the Heart into the Arteries. The evi­dent diversity of Cavities and Turn­ings for the carrying of the Blood both in Children in the womb, and more adult persons, did vex my troubled mind.

Indeed in persons of firm age that oval perforation, or rather communication [which is sprinkled with Botalus the Inventor's name] or, if you will, that Synanastomosis useth not to remain. It is that by which, in the Child in the womb, the Blood directly from the Vena cava filleth the right Ventricle of the Heart; also by the Venal Ar­tery entreth immediately the left Ventricle.

Neither doth that little Ductus remain Pervious, but degenerateth into a Ligament, by which the Aorta of the Child in the womb receiveth the Blood through the Ar­terial vein, the shortest way from the right Ventricle, without any turning into the left.

Then at last, that the commerce of the Heart, with the Entrances of the Vena cava, might be dis­covered, with the famousest Anato­mists I considered the structure of the substance of this Noble-intrail; and in the first place, the three doors of the three-corner'd Valves, situ­ate betwixt the joyning of the Vena cava to the right Ventricle of the Heart, offered themselves to view: I was willing to take notice of their office, which was, to give easy en­trance to the Blood into the Heart, but stopt its return into the Vena cava.

The impervious solidity of the Septi, or Partition of the Heart which lyeth betwixt the Ventricles, denied it altogether a passage. [Page 61]Therefore I inferr'd, the Blood is­sueth out of the right Ventricle into the Arterial vein: And indeed in that place the three Sigmatoidal or S-like Valves give place to it rush­ing forwards, but withstand its re­turn.

Nevertheless having burst asun­der the partition, I viewed the left Ventricle: It differed from the right in that it was of a more ob­long and narrower hollowness: Into two Entrances of it two Ca­nales were inserted, on this side that which they name the Arteria Venosa, on the other side the Aorta was placed, at the boundings of both were placed Valves: This [the Aorta or great Artery] had, as in the Arteria Venosa, three sigma­toidal Valves, to give way to the Blood thrust out, and to stop its return: That [the Arteria Ve­nosa] had two Miter-like Valves, that kept Centry, to give Entrance to the Blood into the Heart, and to stop its flight from thence.

By reason of this fabrick and fa­shion [Page 62]of the Heart, and the offices of its Instruments, I could not any more approve their denying the flowing of the Blood from the Heart into the Lungs by the Arterial Vein, and again its return from the Lungs into the Heart by the Venal Artery.

And lest some perverse people should charge me onely with sup­positions, behold I produce an Ex­periment. I bound with a Liga­ture both the Vessels as near the Lungs as was possible, and then the Arterial Vein in its body was di­lated betwixt the Heart and Liga­ture, beyond the same Ligature to­wards its furthest Branches in the Lungs it became flaccid: But the Ductresses of the Venal Artery al­together in a contrary effect did swell and fall.

But seeing indeed our speech is fallen on the two Veins of the Lungs, the Anatomists have with unfit tearms [in my judgement] na­med them: For what mattereth it, if with the subtil des Cartes, I call [Page 63]that onely an Artery through which the right Ventricle disburthens it self into the Lungs; seeing both the thickness of its Coat, the figure of its Valves, and the office of its Pipe receiving Blood from the Heart, do altogether assimulate it to the rest of the bodies of Arteries? And why, I pray you, entitle they that an Arterial Vein through which the Lungs disgorge their pur­ple streams into the Heart, seeing the testimony of its Coats, Valves and Office, assert it a Vein? Not­withstanding name them as they will, 'tis all one to me, so they be known: But a demonstrative truth in this matter should not have sa­crificed it self to Hippocrates his opinion.

CHAP. IV. The Circulation of the Blood in the Child in the Womb.

THat which we have already shewn concerning the Cir­culation of the Blood, I would have thee [Reader] to understand it chiefly of grown persons: Not to deny its Circulation in Children in the womb, but that in them the Circular motion differeth a little in its passages.

By the Hypogastrick Arteries the Blood is carried into the womb of the Woman with Child; the Um­bilical Vein carrieth that part of it which is best concoct into the Liver of the Embryon: but that which is more serous and unconcoct return­eth by the Maternal Veins unto the Heart as its Pot, whilst the thicker groweth together into the Placenta or Lump, as into the wombs Liver.

The Vena cava thrusteth the Blood, receiv'd into the Embryons [Page 65]Liver, from thence into the right Ventricle of the Heart, where it joyns with it, and so into the left Ventricle thereof, by the then open Oval-passages. The Blood going out of the right Ventricle into the Arterial Vein, partly by an inter­jected little Pipe, as it were by a sloping Canale, it floweth freely into the Aorta; Partly a good quan­tity possessing the Lungs, oppresseth them with so great weight, in respect of want of breathing for the hard passage from the furthest branches of the Arterial Vein into the Venal Artery, that the Lungs of the Child in the womb [if it did not breath sometimes] representing both the colour and density of the Liver, would never swim above water.

Certes, Respiration stirreth up the Blood in the Venal Artery. The Bronchia [Canales of the Wind­pipe] by their breathing dilatation pressing together their fellows, on the one part the Arterial Vein, and on the other part the Venal Ar­tery, to press out the contained [Page 66]Blood so far as the Valves will suffer.

The Blood of the left Ventricle immediately penetrateth into the Aorta, and from thence rushing to the furthest parts of the body, re­turneth by the Veins to the Heart, as hath been shewn in Adult per­sons.

And because the Umbilick Vein emitteth more Blood than the nou­rishment of the Child requireth, the Providence of Nature hath branch­ed out a pair of Branches, the Con­sorts of the Umbilick Vein, either of them from the Iliack, or [which I have most frequently observ'd] from the Hypogastriack Arteries even unto the Placenta. They re­found the Blood that is more than nourisheth the Child into the Liver of the womb, whether this be re­quir'd by the celerity of the mo­tion, or whether the impure mass of the Mothers blood requires a better digestion by the mixture of a warmer.

But lest I should seem to have [Page 67]found out this reflux by vain Ar­guments, put I pray thee a straw into the Umbilick Vessels that be­long to the Placenta or Lump; then blow thou, and the Vein alone will carry the wind into the Child: But on the contrary, if thou blow by the Reed into the Child, the Arteries will carry the wind into the Lump, the Veins remaining al­together flaccid.

At last the Umbilical Vein by de­grees becoming unprofitable, dege­nerateth into a Ligament: by the same chance the Canale of the Ar­terial Vein, going into the Aorta, evanisheth, and the Botalian per­foration is filled: but the Umbilick Arteries nevertheless remain. I have many times observ'd it in cutting up of Adult persons, viz. the wind blown into the Hypograstriack and Iliack Arteries, did not onely shew the Umbilicals near the Navil by the small tumor it did raise, but en­tring their infinite Branches on e­very side, by them its empty tumor [Page 68]declar'd the many branchings of the Artery in that place.

CHAP. V. That the Arterious Blood is partly by Synanastomosies poured out of the Arteries into the Veins; partly being extravasated by the Anastomosies of the Arteries, returneth again into the Veins.

HAving demonstrated the Cir­culation of the Blood to and out of the Heart, 'tis fitting that according to the example of those that are well deservers of the Ana­tomick Commonwealth, we search out, with an inquest resembling the former, its passages from the Ar­teries into the Veins.

Many are of opinion that the furthest points of the Arteries are inserted into as small parts of the Veins; but the smalness of the points of the minute Vessels not to be discerned by any eyes, though [Page 75] [...] [Page 68] [...] [Page 69]arm'd with Spectacles doth not confirm, doth not confute this opi­nion.

They aver also, that wind blown into the roots of the Vena porta within the Liver, doth enter the conjoyn'd Branches of the Vena cava; and that it doth insinuate it self from the Trunk of the Ar­terial Vein into the Lungs, and fur­thest Branches of the Venal Ar­tery.

I have many times tryed it in the Liver, but the Experiment ever failed; I doubt whether more by defect of breath in me, or errour in them. In the Lungs indeed I have found that the common passage of the Synanastomosies of the same Pipes were open.

One day it was my business to view the Arterial Vein, being made bare of all its Cloathing. I did observe it, not with a few knots of Embracements to stick fast to the Venal Artery. Putting a Reed into it in that place where 'tis in­sert into the Heart, I blew; pre­sently [Page 70]the spreading breath did raise the bloodless Canals, and being roll'd to the ends of the Capillar Veins, was received into the hol­lowness of the Venal Artery, which is indeed an evident token of their Synanastomosie. But though it held in the Lungs, yet nevertheless I will not conclude it holds so in the Liver or Muscles.

Indeed I will confess, that by the intermediate openings of the Synanastomosies, that the Blood may be turned out of one Vessel into another, seeing the individible coherence of the Veins with the Arteries in some places, proves this, and their not easy separation with­out tearing of both. But I believe he admitteth absurdly this Synana­stomosis where the Veins have no coherence with the Arteries; yea rather I would believe, that a part of the Blood by the Anastomosies with­out the inclosures of the Arteries, doth abound to be strain'd in the flesh, that that of it which is more exactly concoct may turn to nou­rishment [Page 71]in the simular parts, But that which is not well digested, may return into the Veins, which perchance in all places without have entrances to their most inward places.

For if the perpetual Flux of the Blood within the Vessels casteth forth no Blood without the Vessels, whence proceeds the increase of the bodies bulk? And if the substance of the parts of the body be in per­petual motion, from whence, I pray you, will proceed the restorement of the tabid leanness of withered bodies?

There is indeed some seedy sub­stance in the Blood fit for the re­storing of the decayings of the parts, viz. That which being more concoct useth to unite it self into a fibrous thickness: And indeed, the Blood drawn from the Limbs into hot water, doth spread its se­rosity and colour in the water, when in the bottome of the bason there remaineth a fleshy thickness of membranous dregs compos'd of [Page 72]white fibers, and therefore more fit for the solidity of the body; to wit, that which either remained af­ter the satisfying of the parts, or was melted by the washing vigour, may be, of the following Blood, or was transvasated by the short pas­sages of the Synanastomosies, and did hasten to be recocted in the Pot of the Heart.

And lest any should confound the Offices of Synanastomosies and Anastomosies by reason of the likeness of the words, I call Syna­nastomosies the intermediate open­nesses of the Arteries cohering to Veins for the carrying of the Blood out of one Vessel into another; I call Anastomosies the furthest points of the Arteries whereby the Blood is extravasated and received by the tunnels of the Veins for the gathering together of the same.

CHAP. VI. The beginning of the Blood's mo­tion is inquir'd after; the innate weight of the Blood, though the Arteries should pay the part of a Syphon with the Veins, is shewn not to be enough for its Circula­tion.

THE undiscovered cause of the discovered matter rather ag­gravated than abated my grief: The motion of the Blood is dis­covered, but its beginning being yet conceal'd, challengeth me to [...] new labour, the difficulties of which, (Reader) I will essay to make plain by these admonitions.

The Blood rusheth forward ei­ther by its own proper incitement, or 'tis thrust forward by anothers; we acknowledge it hath no proper one, except its heaviness, whose vertue I will prove vanishing by these following reasons.

The Blood indeed, whom the in­nate weight may carry downward [Page 78]by the descendent Arteries, and the Trunk ascendent of the Vena cava, cannot by the self-same endeavour flow to the upper parts of the as­cendent Arteries, neither by the de­scendent stem of the Vena cava; except, with some famous Philoso­phers, you ascribe the reason of this effect to the disposition of the Ves­sels: For (say they) the Arteries so cohere with the Veins, that you may say not undeservedly their fa­blick imitateth a Syphon.

They call a Syphon a reflex'd Pipe, either whose declining Legs uphold a high Angle, or whose elevat Legs lean on a depressed Angle.

That therefore the ascending li­quor may come to the high Angle of the Syphon, 'tis needful that the Leg by which it should flow, be plac'd under a more depress out­sending Vessel, that from thence the greater weight of the liquid heap may make the weaker water mova­ble to follow it through the other door. So by the ascending stem of [Page 79]the Vena cava, which the provi­dence of Nature hath plac'd a little lower than the Entrances of the ascending Arteries, the Blood flow­eth down (say they) which for this ought altogether following to ascend.

And as the Liquor, rushing by its own weight into the depressed Angle of the other Syphon, is re­flected out of the bottome by its own instinct, till on both sides, by an equal Superficies it point forth the quietness of a just ballance; and if the Pipe of reflection being more short, doth hold abroad a more declin'd openness than the tunnel of the other Leg, it cometh to pass that for the same heaviness, that 'tis poured out by its own pro­per stream. So the Blood [say they] by the ear'd trunk of the descending Aorta throwing it self headlong to the lower parts, of its own ac­cord riseth up again from the bot­tome by the descendent Vena cava, and by the door of the same, which is a little low situate, by a sponta­neous [Page 80]flowing again is refunded into the pool of the Heart. Re­member, Reader, lest the doubtful­ness of the name should trouble thee, that that is call'd the Ascen­dent Vena cava which springeth upward from the Heart; but that which spreadeth Branches from this down to the extremities of the parts, is call'd the Descendent, ta­king the name from its Original, not from its office.

Truly you may say, that with the workmanship of Nature, Truth it self hath conspir'd to their opi­nion, and that injuriously I deny my assent to most evident rea­sons.

But if with me you take notice, that at the same time the liquor ascendeth to the high Angle of the Syphon, that it rusheth downward; and again, that it ascendeth in the same moment from the depress'd Angle of the overturned Syphon, by which it is poured into it: Then it will be clear, how incongruous the succession of continual flowing [Page 81]of the Syphon is with the motion of the Blood.

And indeed the Blood, while the Expression of the Systoles thrusteth it in the wide-open Arteries, at the same moment by their Extremities, penetrateth into the Veins: But then onely it breaketh out of the Veins into the Heart, when the Systole ceasing, leaveth to the Dia­stole its own part by intercourse to be acted. And even from this 'tis clear, that the Blood no waies imi­tateth the liquor in a Syphon.

But because we do hardly depart from those things that please us, I demand, that if the Chanels of Blood play the part of a Syphon, and for that the Law of Conter­posure requireth an equal fulness necessarily on both sides, how comes it to pass, that in a dead Body Death doth altogether empty the Arteries, whilst the Veins remain turgid?

Yea the Experiments of Circu­lation will voyce against the Sy­phon. The Jugular Vein represent­eth the emissary of a standing Sy­phon [Page 82]from its sublime Angle into the Heart: When I had tyed this Vein in the Neck, notwithstanding, by the Ascendent Arteries Blood was sent upwards, yea and above the Ligature it extended above mea­sure the Jugular Vein.

The straitned Pipe of the Crural Vein taught the same, viz. it be­coming flaccid from the Ligature towards the Heart, cleared that it issued the Blood thitherward: But shall I believe that any foolishly will attribute the ascent of this in­to the Heart unto the heaviness of the rushing heaps of Blood into the Aorta?

But neither that Artery it self which watereth the Leg when 'tis tyed [if it be to be attributed to the weight of the Blood, as the motion in an inverse Syphon] can be eva­cuate under the Ligature, against Experience; For the so little re­mains of Blood there, will not be able to thrust upwards the whole weight of Blood which weighteth in the Vena cava.

But when I said, the exhaust Arteries of dead Bodies, do not thou believe 'tis to be attributed unto the evanishing subtilty of Arterial Blood. For this also hath its own density, neither less perchance than that grossness which is included not onely in the Vena cava, but Porta also.

Easy experience will supply my admonition. The wounds of a Li­ving Beast at the same time empty­ing the Vena cava, together with the Aorta, and, if thou please, the Vena porta it self: Let the Blood drawn out of each place settle in its own platter; Let none of them be dissolv'd into a vapor, and except that which was drawn from the Branches of the Arteries blushed with a more clear purple, with a moyst vain trial shouldst thou search after a difference.

Thou mayst in a dying Creature stop the Arterial Blood, if thou tye the Artery in the Leg; and I my self many times having tried this, I beheld the Artery towards the Heart to be [Page 84]tumid, with Blood that did not at all evanish.

Therefore, seeing neither the course of a Syphon agreeth to the Circular motion of the Blood, neither the weight thereof seems to serve for that purpose, yea many times 'tis impediment thereto, as 'tis clear in Limbs hanging more negligently, Laziness making the vigour of the Blood more stupid; we are to have our recourse to the vertue of an ex­ternal incitement, the innate one failing.

CHAP. VII. The impulse of the Systole alone is not enough for the Circular mo­tion of the Blood. In a Diastole there is no Attraction.

THE impulsion of a Systole, Attraction of a Diastole, the rough contraction of the Vessels, and endeavour of the adjacent parts upon every occasion, seem all ex­trinsecally to affect the Blood. Let us discover by an exact Examina­tion which of these, and how much each of them conferreth to the mo­tion of the Blood.

CHAP. VIII. 'Tis shewn by Experiments, that there is not onely a Weight in the Air, but likewise a rarefactive Elatery.

I would treat of the Air's pon­derosity, yea in its proper (as they say) place, except it were an Argument known to all. For who doth not see the Air of its own ac­cord to descend into the Chinks and Ditches, yea even into the low­est Center of the Earth, if you delve so deep? Who doth not know that a little Bladder, the more tur­gid it is, is so much more heavy than it self being flaccid? Who, if he weigh a Gun burthened with con­densed Air [they call it a Wind­gun] will not observe that its weight then is heavier than 'tis when it is discharged? To conclude, to whom is it unknown that the lightness of an Aeolipila, the Air of which is rarified exactly by the force of heat, is not at all to be compared with [Page 90]the heaviness of it being cold?

Neither indeed believe thou that I am affrighted with the opinion of that kind of airy weight in refund­ing the vapours of the Athmosphere. For by the Air I understand the Athmosphere, neither for the present doth my Philosophy ascend higher.

Feign to thy self this, as a heap of spongious, or rather woolly mat­ter encompassing the Earth-watrish Globe, whose superiour parts there­fore are susteined by the inferiour, compressing it by degrees, so that the nearer they come to the Earth, so much the more they are com­pressed compactly by the weight of the parts incumbent; And for that cause by its Spontaneous dilatation [which I call Elater] howsoever the heap'd on burthen do press them down, yet the under parts, if they have liberty, will en­deavour to rarifie themselves.

Hence I inferr, that the lowest of those parts, as being plac'd un­der the whole burthen, so to be most condensed of them all; And [Page 91]for this reason the superfice of the Earth-watrish Orb is pressed of the same, not by its weight alone, but also by the vertue of his Elatery, whose endeavour to rarifie is most valid.

But because they are words, and I have given you leave to proceed from the Ears to the Eyes, I will prevent thy desire, and I will view the misty secrets of the Air by the search of Experience, which I at all times follow as my Leader.

I will produce in the first place some Experiments concerning Va­cuum, or Emptiness, which I be­lieve as yet have not been commit­ted to the Press; no Monuments of my own deep cunning, far be it from me to arrogate to my self the glory of those detected Miracles which were not first discovered to me: For whatsoever I did exqui­sitly elaborate with an exact en­deavour more frequently about so weighty a matter for fear of errour [Page 92]which troubled me, it was imitati­on, and not invention.

I will produce Authors, not of Books, which as yet I have not so much as heard to be extant; but of those Experiments at least which follow, and whose Authority is great, and Name venerable.

CHAP. IX. The Engins drawn to the assistance of Attraction, are demolished.

HAving demonstrated by Ex­periments conquering all stifness, and subduing all belief, That, more than in a wool heap, the heaping up of the intricate parts in the Air, and the Elater innate therein for rarefaction doth beat the Globe of Water and Earth; I pro­ceed to examine their Engins who advance Attraction.

CHAP. X. The true Causes of the Blood's Mo­tion are discovered.

HAving demonstrated what a light incitement the weight of innate gravity is to the Motion of the Blood, and having observ'd by evident Experiments that the Hearts Systole sufficeth not alone for this effect, and having altogether cut off the helps of the Diastolick At­traction, it remaineth that we con­sider the Construction of the Ves­sels, and that we ponder their Com­pression from the Agitation of the neighbouring parts.

'Tis certain that the Vessels are straitned by Spontaneous Contra­ction, or by Violent.

I call that Spontaneous whereby of themselves they leave their swel­ling fulness.

I call that Violent which an Ex­ternal Cause produceth.

I demonstrate the Spontaneous after this manner.

CHAP. XI. It is demonstrated, that the Chyle is also thrust into the Lacteal Veins, and is driven towards the Heart, and that it is not sucked.

THE Motion of the Blood being perfected, it may easily also be shewn whither the Chyle is roled.

All know that the Chyle is ex­press'd from the Aliments that fall into the Intestines from the Sto­mack which concocteth them, and [Page 142]that they go through the Tunicles of the Intestins by the little Pores opened by Nature into the Pipes of the Lacteal Veins, But whether the Pervious Intestins imitate a Sive or a Sponge, their double Coat (which is proper to them) doth not denote any one of them, but them both. Nature hath wo­ven their outmost coat with the threds of most small Fibers artifi­cially, like a st [...]aining Sieve, unto which by her providence with a wonderful anointing she hath glewed on the inside a wrinkling or spongeous, if you will, lining, of a most soft substance; that both the sharpness of the Aliments may pass unhurting them; and that that juice which is most subtil may be strain'd out of the Excrements into the La­cteal Veins.

The former Experiments clearly shewed the passage of the Chyle; now we are to search whether the Chyle is thrust or drawn.

CHAP. XII. Of the Transcolatory use of the Liver.

AFter I have taken from the Li­ver that usurped Glory of Blood-making which undeservedly it retain'd for so many ages; 'tis just I should assign to it that duty for which it was made, and plac'd in the Forge, as they call it, of the first Region, and that I should dis­close the true office thereof.

Besides that office which it dis­chargeth, as is said before, instead of a Pistill beating the parts plac'd under it in the Lower Belly by the motion of Respiration; The Liver also doth, by that great stream of Blood it receives from the Vena porta, administer Heat to the Sto­mack to help the Concoction of the Meat; And moreover, doth strain the Blood through his most fit Pa­renchyma [Substance.] And as the Reins purgeth the Blood of its Se­rum, [Page 166]and the Melt of its Acidity, so the Liver doth deliver it of the fellowship of the Bile that is mixt therewith.

For if no sourse of Chylous mat­ter doth come unto it, neither there­fore doth the Liver impurplush any Aliment into Blood; And onely the Trunk of the Vena porta [which likewise doth not from any place receive Chyle, as hath been shewn] doth fill it with the Blood where­with it swelleth; Neither doth any man wisely [if I be any whit wise] repute Bile the Excrement of the second Concoction, neither should he esteem it separable by any other Instrument.

And indeed you shall not find any where, in any kind of Living Creatures, the Blood without the mixture of Bile; The yellowish and salt Serum will testifie so much: Except perchance in some Crea­tures, to whom meek Mistris Na­ture hath concocted a sweeter Blood; As in others, in which she [Page 167]hath infus'd Blood without Acidity, whom she hath endued either with no Melt at all, or at least with a very little one.

The continual Heat, which che­risheth the Heart, and warmeth the mass of Blood, dissolves all the subtilest parts of the Serosity into Vapours, and again Concocting the rest [which by its frequent frying, and pressing of the sweet from the salt, I call the remaining Progeny] it would altogether turn it to Bile; Except the providence of Nature for the purging of the bitter Excre­ment, or rather of Salt thickned by too much Concoction, had en­dued the Body with a fit Emun­ctory.

And as Fullers use to colour their hands with those Liquors they die with, so that Bilous Intral, the Li­ver, according to the divers tinctures of Bile, either is yellowish red, or of a languishing ash-colour, some­times blackish green, or brown, though the Blood be exactly red.

Hence in the Child in the Womb, in which there is never any Chyle bred, about the beginning of its forming, the Liver hath its Saffron-colour'd Cystis full of Bile, though other waies the Blood be of a purple die: Which is an evident Argument, that the Bile is not the Excrement of the Second, as they call it, Concoction; but an Ex­crement of the Blood, which (Blood) is onely transmitted into the Liver of the Child in the Wombe.

Neither may be the fervid Blood in the Mother, and strain'd by the Uterin Liver [the Lump] in the Ma­trix, should in such purity erre in the Veins of the Embryon, except it should leave the greatest part of it in the Liver, into the which it first floweth by the Coeunt Pipes of the Umbilick Veins.

And this, as I believe, is the Chief Office of the Liver in Living Creatures.