The economy of the animal kingdom, considered anatomically, physically, and philosophically

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rises through the Vena cava, after passing the heari, is ali con- veved toWard the besorementioned arteriai sinus of the head, Whicli is theu in a state of expansion. But When this sinus is constricted, and the blood is sent Dom it tuto the umbilicat ves- seis, it then propeis the blood it has received through the superior cava, into the heari, at Whicli timo the blood Whicli has passed through the heari, cannot be driveti toWard the sinus, inasmuch as the latier is constricted or closed, but the blood is ali sent toWard the descending storta, and so On. Thus Whilethis sinus protrudes the blood Once, the heari performs the Same operation tWice, Whicli produces tWO successive motions in theauricles and tWo in the ventricies. Lancisi seems to confirm thesaci of this mode os circulation, When he describes it in these WOrds: ΜOreover, it is Worthy Of remarii, that as SOOn as themotion Of the corculum begius, certain fine purpurascent lines Whicli prove to be the umbilicat vesseis) are traced Dom theborder, Or Dom the circumseretice of the colliquamentum in this siluation, as We said above,) to the centre of the cicatricula, Where they terminate, and becoming enlarged forna those ve8icles, Whicli are alternately fillud, elevatod and reddened by the influent blood ; in other Words, undergo diastole,V kc. n. 245 .Τhe reality of this first circulation is thus confirmed, RS Wellas of that Whicli comes to bo describod in the conified heari, besere the lungs respiro. On this subject We shali not d eli

RHd the pulmonary artery communicates through the ductus

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arteriosus With the norta : Which Would by no means have beenthe case, hau not sueti a circulation proexistud. I Would noWmerely add the proposition Whicli follows in the series of the induction, nam ely, that the circle which the blood thus describes, is as it were Guble, and resem, but yet continuous. So Dny usthis circulation continues, two motions must emist successively in the auricles, and two in the ventricies.

334. The mode and determination of the circulation in theunited or conical heari, binore the lunos bellin to respire, is similario the above. The heari does not assume the conicia form besore the severith or eighth day, Or before the lungs mine their nppearance. On the 5th day of incubation, V says Lancisi, onemay Without dissiculty seu that the right ventricle of the hearthas approachen to the lest, and is lying upon it, so that the twono longer appear separated, but conjoined aud solded; and muchmore evidently so on the solio Wing days, When est the segments of the corculum are paclied into One mass, and tWisted together in their respective places so as to form a single coneV n. 245).

lungs Was discernit,te, the littio ribs Wore solidissed, and thomuSeles spread Over them externaltyV u. 242). As I have al- ready remarhed, Malpighi states that at this period similarmotions are observabie in the heari, numely, tWo in the auricles and tWo in the ventricles n. 242).335. Thus the blaod carried down froni the brains throqvh the Superior vena cava into the right ventricte, is propelled therefromthrouoh the ductus arteriosus into the descending aorta, and 8o into ali the provinces of the inferior reston. Then it ascenda throush the inferior vena cava, and is driven through the foramenovale into the lest ventriole, and from then e torvards the brains: and so on continuat . Or that ali the blood of the inferior cava, Or rather of the body, after passing the heari, is carried up-Wards to tho bratus; and that nil thu blood of the superior cava, Or rather of the brains and spiunt marroW, is carried doWΠWardsto the body. Tho blood also of the subclavians runs doWn into the Superior cava, Which seems to bo tho reason Why the germos the Wings, as Μalpighi relates, begius to appear in general

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ubout tho timo of the sirst circulation.) So that thoro is not adros of blood but returus besore this circuit is performed. Munniciis is of the Same opinion Where he says: Thus thoblood that comes through the ascending vena cava Dom tholoWer paris, passes through the foramen Ovale into the pulmonary vein, and ait enters the lest cavlty of the lidari. But thoblood that comes through the descending vena cava Dom theupper paris, is ali sent into the right ventriciuV n. 320). Vor-lieyen evidently thiniis that a certain portion os tho blood of tho inferior cava passes into the right ventricle; for he says: What the actuat quantity is that passes through the foramen Ovale into tho lust ventricle , I bellevo it to be impossibie to determinuV n. 316). Is merely for the salie Of the argument We

suppose the existetice of such a circulation, it is clear that we

tion, or that the blood flows Dom the superior cava into theright ventricio bufore it soWs Doni the inferior cava through the foramen ovale into the lest ventricle; so that the circulation maybe compared With the figure 8; the superior circumflexion Osthis figure representing the superior circle of the blood, or that Whicli passes through tho braius and the two medullae; While the inferior circumflexion represenis the circuit that passes throughthe b0dy : tho conified heari being the concurrenoe Or internode of the two circles. The circle is uot hoWever so uniform as is represented in the figure 8, because thu blood describus iis

figure in accordance With the members placen in the circle. Nevertheless the comparison may serve to illustrate the COΠ-tinuitu of iis fluxion. Moreover since the current that describes

aud continues this doubie circle goes On perpetually, it sol-I0Ws, that it is present in the superior cava, Or enters into theright ventriclo, besore it is present in the inferior cava, or floWSinto the lest ventricio; consequently that there are tWO motionSin the auricles and two in tho ventricles, as Alalpighi has Stated. I 0ught to add, that ii dosis not solios Dom this, that one Ventricle expels iis biood bosoro tho other, although the blood soWs into them alternatoly; for as soon as one is filled so is the other, at least but very littio astor; thus Oach concurs in Simultane-0HSty expelling the blood. For tho muscular series in tho heari dre ADt 0uly particular aud propor to each ventriclo, but are alSO

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common to both; for Whicli reason the blood cannot be expelle lexcepi by the nid und cooperation Of the common mUSClOS. This, I suppose, is What Lancisi means Where he sayS: The motions of the auricles, whicli as I before suid aro observed to bealternate With those of tho ventricles oti the sirst days of incubation, appear to be successive rather than alternate after thelieari has attained iis conical formV n. 245). Τhat there is Such a motion and pulse of the heari, and such a circulation Osthe blood, in the unborti foetus, no One can doubt; nevertheleSSit is tho businoss of tho intellect to ascertain Whether this circulation coincido with the figure of the primitive conical heari, and whether it bo the o ly mode os circulation that can be conveniently performed, and lienee is neceSSarily performed, Solong as a passage is hept open through the foramen Ovale and duetus arteriosus. We are to bear in mind be re haud, that such a circulation of the blood, and such a pulse of the conicatheari, exactly coincide With the circulation and pulse of the vesicular heari besore it is rolied into a cono n. 330-333). Thatit coincides also with the sirsi and most simple circulation sit. 327-329), Whicli cannot produce any other than this continuous and composite circulation. That also Dom no Other cana third circulation be formed, combining a simultaneous influxionos blood Dom both the superior aud inferior cava n. 345).336. That ali tho blood of the superior vena cava floWs into the right ventricte, is in some mensure manifest DOm the continuity of that vein With the ventricle; for the ventricle is soimmediately subjacent to the vein as obviousty to receive thestream that comes Dom it; shewing that there is a continuationos the fame stream into it. as it Were into iis large recipient bed. From this ventricle there is no ouilet but what leads into the pulmonary Rrtery, and Dom the pulmonary artery, When the Iungs ure Ahut Or constricted, into the ductus arteriosus, Whichaccording to the descriptions is of sufficient magnitude to receive and transmit the entire stream. The Whole of the blood, then, that is transmittest through this iube, cannot possibly be con-Veyed to the carotids, and through them to the bratus; for the

authors, and among the rest, by Morgagni, Who Saγs that this

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arteriat iube is carried tuto the beginning of the descondilignoria aster that vesset has given Oir ali iis branches to the supurior regions' n. 322). No one therofore cun doubi that ali the blood of tho right ventricle is conveyed to the inferior regions of thobody through the medium of this iube, by Whicli as by a bridgo

the pulmonary artery is connected With the descending uorta. 337. Anatomy further shews, that ali tho blood of tho inferior cava soWs through the foramen Ovale into the lest ventricie ; for this foramen opens just ut the entrance of that veluinto the right auricle and ventricle so as directly to intercepi iis

stream; the aperture is also of sufficient diameter to absorb and transmit the Whole current. The foramen,'' Says Verheyen, se is siluated belWeen the inferior vena cava and the pulmonaryvetii; opening into the former immediately below a tubercle that lies adjacent to the first division of the vena cava; and into

the pulmonary vein near the lest ventriete. . . . It is SO large ut first toWardes the vena cava as to exceed the norin iiseis in sige,

but Where it terminates in the pulmonary vein it is someWhat narroWer. In the upper pari, toWards the right ventricte, it has a raised border to prevent the blood Dom eastly passing it by; but at tho lower part it is comparatively stat and even, to malle the entrance of the blood more easyV n. 3I6 . 338. The whole of the blood that is conveyed Dona the inferior cava through the foramen in to the lest ventricte, is carriedaWay Dom this ventricte toWarus the brains and Superior paris. It is at the fame time conveyed also Dom the bratiis to the Spinal marroW, and through the subclavian and axillary arteriesto the arms; although ali the blood retiarns froin the brain through the jugular vetiis, hom the spinal marroW through the

the inferior paris or to the body, as is obvious is We attendio the rule given in n. 228, namely, that an artery in PreSS-ing iis biood onWarus, strations itself and ulmost closes in relation to the antecedent paris of the vesset, in Order to puShthe Volume doWΠWards. Thus the stream expelled through the arteriat iube into the descending aorta, cannot be mixed With the Stream expelled ut the sume moment Dom the lest ventricle into the Superior part of the aorta; for as SOOn as the blOOd rusties

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cupied by the blood conveyed through the ductus artoriosus, itis evident that it cannot receive much blood froin the lest ventricte, und there re that nearly the Whole, or at least by farthe greater portion of the bl od of this ventricio, is distributod through tho superior paris of the bodyV n. 316 . 339. It Only remaius for iis to explain, hoW tho blood of tho inferior cava can be nil transmittest through the foramen Ovale, without mixing With the bl ood of the superior cava, yet SO as tonitoW a smali portion, according to Verheyen n. 316), to findiis Way into the right ventricle; Or hoW the superior cava candistinctly carry iis stream into the right ventricte, and the inferior cava distinctly carry iis stream through the foramen Ovale into the lest ventricio; for it might seem as is nothing could

With the stream of the other : as indoed is the case in the conical heari aster birth, and particularly When the foramen Ovale isolosed, and the blood flows Dom the right auricle into the right Ventricte, ut the fame moment that it soWs hom the lest auriclo into the lest ventriclo: a motion Whicli is compound and simultaneous, While the former, of Which We have been treatinia is respectively successive and Simple. Let 118 See therelare, I say, in What manner tho blood may be thus transmitted; nay, thalit cata be transmitted in no other mander than the One We have mentioned, is We graui the existence of a SuccessiVe motion. In the human subjeci, there is a septum siluated belWeen the O Venae cavae; and in brutes a tubercle likowise. 2 his divi-

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1lows in Dom the inferior cava, the Septum is produced ns sar astho bordor of the entrance to the right Ventriete, SO as ulto-gether to intercept the communication belWeen tho blood of tho superior and that of the inferior cava at the moment of tliotrinflux. For tho blood of the superior cava presses iapon this septum, but not that of the inferior cava, b ecause the latior dous nos aut then, but asterWards in Succession; so that iaponone giving Way, the Other acts upon the intermediate septum more effectually. Besides We Iearn DOm observation, that Whilo the auricle and ventricle are in the state Os diastole and impletion, they RSSume a comparatively oblong form. Thus Lancisis s : Every time the whole quadricave muscle of the heari is strat ned and constricted, the auricles are seen to be depressed to-Ward the base, and to descend; and the ventricles to be elevatentoWard the base and to ascend; so that the body of the beari, Which belare Was Oblong, beeomes nearly round nnd spherical.

intermediate septum is also elongated so as to take aWayali communion belWeen the two currenis, that no blood may atthat moment escape Dom the inferior cava into the right ventricie. Add to this, that tho foramen on the fide nexi to the Vena cava, When the blood yields, is not opened, and at the Sidenext to the right and lust auricle, is so draW11 and contracted ast0 lose iis ovat figure, and assumo that os a chinii or line. Thatthe bl00d of tho inferior cava then yiolds, is proved by the reticulated valve os Eustachius; of Which Heister Says: Eusta-

ing froin the livor, just Whero it bogius to merge in the right Uriele, occupying iis autorior half, and forming a Lind of roti

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blood descending 1 rom ille jugulars through the Superior CRUR, DOm encountering too violently the blood ascending throughthe inferior cava. But Winslow . . . shews that it not only has the use that Lancisi assigiis to is, but Ospecialty in the laetus atbirth, . . . SerVeS to prevent the bl od Dom flowing bacti Domthe right auricle or superior vena cava into the inferior Venncava' n. 120 . Thus every arrangement conspires to the production of this effeci, numely, that the bl ood of the inserior caVa may eaSily give place to that of the superior, and that theblood of One cava may not be mixed With that of the other, and that asterWards, When the inserior cava acis, iis biood may notrusii into the right ventricie, When atready fuli and whon the Vnives are Closed; nor agnin into the superior cava, there beinga lance interposed, Which seems to be pushed aside in consequence of the stream Of the inferior cava giving place to that of the superior. But the case is otherWise When the superior cavabegitis to aut simultaneousty With the inferior, as it does asterbirili, for then the intermediate lance is raised up On both sides, and thus the one Stream is no longer intercepted and Separated from the Other. Theresore during the period of this second circulation, thelieari stili acts under the auspices of the brains, so that as SOonas the bruitis send doWn their blood through the jugular vetiis, the heurt is bound to aut, and to receive the adVancing Stream, although not at the fame moment in Whicli it receives that whicli comes Dom the body, and whicli as yet no muscies expelinto the inferior cava: c. But these ObservationS are induc

tensive and weli ascertained series of facts besore We can decidetapon a subject of suta vast importance. Thus then the two Circulations are Concordant, namely, the firsi and the last Withthe intermediate, and thus We have explained the propositionthat solioWs nexi in the series of Our induction,-the heartiiset distinct0 determining the stream in both cases. This is the purp08e of the foramen ovale and ductus arteriosus, without whichsuch a circulation could not be carried on. 340. Thus besere the blood is allowed to travel throuctu theiunos from the right ventricle to the lol, it is ali sent to the brainsprevi0u30 to beino conveyed to the bo and iis viscera. So that

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it may ulmost be said, that the bratiis then porsorm the office of the lungs, sor as is generalty known, ait the blood afterWardspasses through the lung8. The reasons appear to be, I. That nothing may be formed in the body excepi under the auspices of tho braitis; so that the fibre situli not be able to aut against the bl od, nor the blood against the fibre; nor consequently the b0dy, in any respect, against the determination os the formative force: these being the only conditions On whicli the Whole and the paris ean groW in mutuat concord. 2. That thebratus may instat and ns it were initiate their primitive corculum into ali iis functions, test asterWards, When it is test toitsolf and tho blood, discord should prevail betWeen the vesseis and the fibres. 3. That the braitis may require and derive to

the egg, ali things that can possibiy conduce to the work of formation and groWth; sor the bratiis have the prerogative os draWing up and demanding the proper quantity and quality of bl00d n. 348, 349 . The potnt of srst importance is, that thesibres bu providod with spiritu iis fluid; for tho fibres do ali thepublic and private business of the body, and there is reatly nothing alive in the body but the spirituous fluid in iis ownsbre and in the blood. 341. And lest the brains should be contaminaled by foul blood,

it is Frst passed through the liver, to underyo puriscation. Num berless facts tend to fhew that the liver is the laboratory forthe purification os the blood, facts observed both in insanis and adulis, to say nothing of embryos. In adulis, ali the hard, old and obsoleto blood, and the correSponding Serum, appearto be sent aWay to the liver n. 99 . For the vesseis that runto the liver arise in the region Where the blood must purisy itselffrom mixed heterogeneous and impure substanees; lar eXample,

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uni ted With fixed salis and earthy matter, and a substanee Whichis eastly converten into calculus and grit. Henco the quantityof this excrementiti Ous substanee increases Whenever the bloodis clogged With numerous olly and Sulphurous particles n. 98, 99). Iis quality is also impure in proportion us the bloodi Ors under any serious diSense. Reverhorst,' Dus. de Motu

Lilis Circulari, &c., k 49.) It is also deposited in the duodenum

and intestines, in order that such excrementitiOus substance m nybe voided by this passage, just as the urine is voided by anotherand proximate passage. For this renSOn the nivine excretions aretingod With a bilious and hepatio color in proportion to the quantity of the impurities supplied. But this does not prevent both Linds of bile, particularly the bile of the liver, si om being os very considerable use besore their ejection; lar a bitter, pungent, irritating, purging, Styptic, emetic Substance of this nature, is required by the intestines in order to goad them to motion, unditi ordor that the Dod that has passed through the pylorus Domthe Stomach, and been maceraten, eXtracted, and iuSpiSSaled, viay be dialy operated upon by the requisite menstrua taliensrom the blood. For the chylopoletic menstrua solioW each Other in an Orderly Succession, ne Ording as the laod is deprived of iis beller juices; as for instance, the saliva, the liquor of the cesOphagus, the gastrie juice, the pancreatic juice, the bile of the liver, Whicli is potared forti, continuulj, and the juice of the gall-bladder, Whicli is potared forti, Only as occasion requireS, and whicli is supplied at ollier times, Or in a larger quantity,