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

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quently tho circulation of the blood, is regulated, and in conformity with tho state of the circulation, the animal economy in general n. 178 181).450. Wo besore observed n. 294), that the stightest stimulus Leeps the primitive corculum, With iis early simplicity of structure, ambiguous With regard to the flux and reflux of the blood, or disposed to go Osr in Whatever direction the force of the brain, as being the strongest, compeis it, und that it thus commenees and constitutes iis oWn equilibrium, and that of iis pulses and arteries. The equilibrium thus commenced in the primitive corculum, is retained in the adult state, but through the medium of the coronisy vesseis; for by these modes Os transferetice of the blood proper to the heari, it is provided that the superfluousquantity of Venous or arterial blood may nOt injure or destroythe natural state of the Lingdom n. 445-447). Thus it is that in the heari me sun a representation of the body and animal

45 I. Is tho sold of least vessuis be that Where nature mOSteSpecialty plays, and celebrates nil her animal sporis, and those vesseis depend on the governance of the braitis more immediately than the largor; and is in the sold of thoso vesseis changes Oecur according to nil the actions and affections of the brains, and whicli through the intermediate arteries affect the pulse of the hoari; and is the least vesseis be considerod as placedin One extreme Of the Sanguineous system, and the heari aspiaced in the Other, maintaining a mutuat relation to each other through the medium of the larger arteries; and finalty, is thelieari itself be encompassed With a similar field os least vesseis, according to our propositions sit. 234, Ι.-V.) ; it follows, that there is no change arising either Dom the bratus or the body

sented in the heart. When the transferent vesseis n. 437, 438)are multiplied beyond their due Ilumber, or Open too Widely, they represent a Weah, timid, un8teady State of miud, and a corresponding state of bOdy. With these transferent vesseis theretorquent Vesseis of the lest ventricle concur n. 435), and the

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Strengili Os the nervous, arterial nud venous systems; and WiththeSe the retorquent vesseis of the right ventricle conciar. Butthe refundent vesseis both of tho right anu test auricie, When theyare PreSent, and When multiplied aud expandod beyond their jUSt proportion, are significative os frequent changes of the bodyand animal miud; os irregular beats of the pulse, frequent inundations and palpitations. This is particularly the case WheΠ-eVer, instead of Only a single largo orifice of the right auricie, Wesnd Severat in number, reciprocatly communicating With cachother by very conspicuous tWigs n. 428-430 ; to say nothingos Other varieties Whicli ure res numerous as individunis them-Selves. The appenrance of the beari depentis principally uponthese Vesseis; thus they alWays pursue in one heari a disserent course Dom What they do in another, and opon With disserent orifices. Helice u e may See hoW rude irregular motions and impulses occurring Dom day to day, deprive the machine of thelieari, and the entire Sanguineous system, of their integrity of state, forcing open passages Whicli ought to be closed, constrict-ing those Which ought to be opened, and thus inverting the proper ordor: hoW by these means a nature is at longili superinducod whioli rusties With blind instinet in to the lusis that necessarily result Dom an nitered fabric Of the heari, in accordance With What we have observed on the subject of the heart of the

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453. By Way of appendix We shali here subjOin a feW remariis upon the composition of the blood in the heart. The right ventricle is as it mere the great vat or casti of the system, in Whichali those fluids and essetices are mixed together that form theingredients of the red blood. In this receptacle one element iScommingled With another, and in this state os commiXtion, Orrather convolution, they are nil transmitted into the Iungs, inorder that the purely aeriat elemenis, in the neW chyle particu- Iarly, may be ejected through their secretory and excreto ducis into the ΠOW contiguous atmosphere, and that nothing but WhatiS of R Sanguineous nature, and Lindly to the blood, may botransmitted through the vetus to the lest ventricie. But the heartis not only itself a generat mixing vesset and vortex, but is also the srst Orgati that operates to compound the blood. It is WolllinoWn, that nil the Desii chyle passes through the thoracio ductitito the sub clavian vel , and that When there is none ser the me- Seutery to imbibe, the lacteal vesseis convey lymph. It is likeWiso known that ali the old, and also the recompotanded blood in the

and that the whole of the spirit Whicli has Once been excluded, gyrates through the medullary fibros of the brain, and ali thenow blood Whicli is there eliminaled by iis chemicat laboratory n. 360 , is carried doWnWard into the jugular and subclavianveius. Ali these essences and menstrua, diversified as they are,are frst conjoined With each other When collected in the right sinus of the heari; and in order to compose genuine bl OOd, Undergo continuat changes, as explained in Chapter I. But besoruthey experience their severat vicissitudes, they undergo a state Ospreparation in the heari, Whicli is not ouly a vortex for the reception Os these elemenis, but a vesset preparino und disposino liquids

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for composition into blood. Τhis ossico the hoart could not por-Drm excepi by the translation and circulation of the blood through iis proper arteries and veitis; for the heari is encOm- passed with a fiuid os least vesseis, in Whicli sold ali naturalchemistry is carried On, according to the structure there preSent

impressed, travel only With a velocity eques to the disserenoebetWeen the force impressed, and the force lost by resistance; or according to a rule Os physios, in elastic hodies the larce resulting Dom collision is equat to the antecedent collisive forcestaken collectively, yc. In non-elastic hodies the rule is disserent). The case is the fame With respect to tho liquids in thehoart. Os ali the animal fluids tho spirit or spirituous suid istho most volatile and highly elastic, nexi to Whicli in volatililyand elasticity is the puror blood, and nexi to this the red blood, n. 100-102). Is noW there bo any chyle, or any Sexum, Whicli, si om being associaled With various Linds of essentiat Salis,

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possesses biit a smali degree of elasticity, it Will solioW, sincothese constituents have not yet undergone their conjugal unition, that at the moment of systole, Whicli is a Strongly impul- Sive force, the most elastic among them, according to the laWAwe have cited, Will move the sirsi and laremost, and the rest in Succession, accOrding to their degree of elastici ty and gravity. Henco that ali tho Deo spirit Wili travol firsi even through theminutest pores in to the motive fibres, and animate iis muscle. Now tho heari is the sirst of thu bodily organs to partake of thenectarean fluid conveyed froin the brains, bocause the lise of this organ is of the sirst importance, and there re it should bethe sirst to lasse of the cup, besore passing it to the others. Τhesibres of the heari are therelare providen With the sirsi and purest essence Os all. The other parts of the blood, Whicli are inert, and are nevertheless enclosed in the ventricles Or lacunae proper to the heari, either enter no sarther femoubunt , or is urged into the seshy ducis, are at the moment of diastole sentinio the coronary veitis, or bach again into the lacunae; sorduring diastole, the commissaries of the heart lie Open, RS be re

455. But let iis pursuo stili furthor the subject of this spirituous blood, and seu hoW it circulates through theSe veSSel S, RS SO many Serpentine Chauneis, in Order to intermix again Withtho blood. Tho blood that passes through the refundent Ve8Seis, and that Whicli passes through the retorquents of the right auricle and ventricle n. 433, 434), immediately returiis into the generat sanguineous stream, With Whicli it associates after hav-ing completed iis circuit. It does not join the former Sangui-ΠCOUS current, Whicli is atready expelled tuto the lungs, butit joins the neW current as it floWs in Dom each cava, and in Whicli it is bottor prepared to take iis place. Ι hoWever, it does,not yet combine With this stream, but flows Dee, it is again propelled, as besore, by the force of the heari into iis motivo fibres and flamenis, and returus into aDother SanguineOUS CHrrent. Τhis it can do tWo, three, or Dur times over, be re italloWs itself to bo conveyed into the lungs, in consociation Withthe other currenis. The most puris est blood moreOVer comes Dom tho lust ventricte, through the retroserent vesseis n. 439), that is to say, the bl00d that has been once carried through the

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IungS, and then returus into the right auriclo. The purest bloodis thus transmitted through tho retorquent vesseis; that is tosay, the bl ood that has not yet reached the lungs, is mingled, in the proper vesseis of the heari, With the blood that has once, Ox perhaps tWice, passed through the lungs, and come in contactWith the atmosphore. It is in the performance of theSe Operations that the chemistry of the heari, or iis preparation of thebl OOd, appears to consist,-Operations Whicli talie place in orderthat the blood may be duly constructed, by acts of discrimination, SequeStration, division, and reabsorption n. I99).

expelled through the muscular layers principalty toWard thebase of the heari, and it is for this reason that there is here Such a collection of lat; they are uiso expelled toWard the division of the ventricles, Dom Whicli the foregoing muscular layers begin, Whicli is also the most tranquil region of thelieari, Where the muscular planes are more relaxed, und the

Coronary VeSSel S are largest. It is only in this diroction that the common action Of the heari can send those particles that, astor the division of the globules, floW in a Dee state, and be- come us it Were the elements of an extremoly sne sui. But thelympii that is separated, is sent by the proper vesseis Of the heartio iis sursaee, Whicli for this reason is seen to be irrigated MihSO great a number Os lymphatius. 458. There is a great similitudo betWeon the vesseis of the hestri and those of the brain, so great indesed, that With no otherscan the latior be compared bellor than With the former. FOr, I. The vesseis of the brain depend on iis generat action, and Commence and complete their systole and diastole, as tho braindoes iis animation. So the vesseis of the heari are actualed

sol ely by iis generat motion sit. 420). 2. All the large aud

' An error Occurs here in the numbering of the paragraphs in the original.- Tro

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are the vesseis of the heart n. 349 . 4. The vesseis of thobruin porsorm their diastole When the bratu compresses itfel and vice versa; the fame is the case With the vesseis of the hoart n. 423 427). 5. In the Vesseis of the brain there is a species

of physical attraction, or of pumping, as in Syringes u. 349) ;tho fame thing is found in the vesseis of the hestri; for Whenthey are stretched lateralty, and ut the fame time shortened, theblood necessarily soWs into the space thus created. 6. During the constriction and extension Os the vesseis and sinuses, thereis no passage DOm the arteries of the brain tuto the vetus, Orfrom the vetiis into the sinuses; but only during the period of the dilatation or implotion n. 349). The inverse of this is thecase With the vesseis of the heart. During constriction, their communication is Open by means of the commissaries betWeenthe arteries stud vetus of the heari, or belWeen the lacunae and

panSion, ali communication belWeen the arteries and vetus is tali en aWay, nor is there any passage DOm the arteries exceptin to the motive fibres n. 414 . The reason os their disseringsrom each Other in this respect, is, that nearly ali the superficialvesseis of the brain ure arteries, the vetus being rejected to the extremities of the hemispheres, or to the large sinuses,) Whilenti the supersciat vesseis of the heuri are vellis n. 421, 422 . 459. Wo have suid that nearly nil the superficiat vesseis Ofthe brain are arteries, the object of Whicli is, that the brain maybe alWays in possession Os strength and lise; for the strengthaud liso of the body lio in the arteries n. 23 I); and internalty

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Ona the bratus is internat, and every cause proceeding Domthe hestri or blood is comparatively externat. Uenee it is manifest, that ench particular viscus of the animal body has iis oWn Science of angiOlOgy, or iis OWn particular doctrine Os arteries and voltis. It is evident also that this doctrine, although thesirst that is propounded, must nevertheless be the last that canbo brought to persection u. I).

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460. BoΕΠΗΑΑvΕ. The heari and iis auricles are real muscieS, and aut Mith a muscular force; they aci, that is to say, When ali iis fibres, Simultaneousty shortened, diministi the tength of the heari, increase iis breadth, accurately contraci the cavities of both ventricles, dilate thetendinous lips at the mouilis of the arteries, shut down the lid-like Valves of the venous orifices, and express the contained liquids With great force, through the dilated molitiis, into the arteries. This is the systole, or Violent contraction of the heari, in udiose structure there Seems to be a Wondersul and occuli propensity to perserin reciprocat acts

of systole and diastole, and this, not onj during lisse, but even after death ; ΠV, after the heari has been separated froin the body, and evenwhen it is cui in pieces. And that the blood is then forced olit, and propelled by this muscular contraction, is proved by iis jetting sortii When the pulmonary artery, Or the storta, is opened near the heari in aliving animal; by iis expulsion froin the heari, when the cone of thel alter is raised upWards, and a Stice or section taken from iis apex; by the pressure upon the finger When inserted into the Wound thus made; by the SWelling, tension, hardness, and paleness of the fibres; by their contraction Succeeding and not preceding the act os impletion; and by the depletion being concomitant upon the shortening of the heart. Is the eighth pair of nerves be tied, or divided, in the nech, the motionos the heari languishes, palpitation ensues, With great distress to the

animal, and in a stiori time the motion Wholly ceases ; Which shews that the origin and continuation of the systole of the heari is attributa-ble to these nerves . . .. Observe, this is according to Lower; butas to whether it be true or nos, See Morgagni, Advera. Anat. V., Anim.

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froin the compression of their nerves by the dilatation of the large arteries ; and the corona arteries being empty, the fibres are narrOWedand elongated, and the distance belween the base and the apex of thelieari is increased; the pressure of the walis on the cavities is talien oss; the valves of the venous inleis Osrom the auricles to the ventrietes aredrawn togard the apex of the heart by the fleshy columns to Whichthey are attached; the auricles and venous sinuses contraci, and fili thecavities of the ventricies. This is the diastole, or the natural State of the heart. For that at the time of diastole tho ventricies of the heartare siled With blood, may be demonstrated by opening one of the large arteries near the heari; by turning the heart of a living animal upWard, and culting it transversely, When it Will be seen to receive the blood during diastole, and not to discharge it; by the inspection os animais opened a litile besere death; by the absence in diastole os pressure

The bl od conveyed to the venous sinus, may be driven by iis hollow muscle into the right auricie, When relaxed, for there is thennothing to oppose it, but iis progress is assisted by the motion of the Subsequent venous blood pressed in the fame direction. But since theright auricle, like the lest, is a large, hollow muscle, furnished with innumerable arteries and Veius, and composed of tWO rows Os strongfibres, running in contrary directions to Opposite tendolis, and leaning by one tendon On the venous mouth of the right ventricle, while it is attached by the other and harder tendon, Whicli is nearly circular, tothe vena cava; it is evident, that by the contractile force of this last, the bl00d may be expelled with a pomeri ut impetus into the right ventricie, When relaxed. For the heari being then empty and elongated, and the three tricuspid valves drawn bach lowards iis fides and apex,

by the tapering and oblong feshy papillae arising Dom the fides of the

right ventricte, and whicli are themselves also draWn bach; and liencethe passage being susticiently open, there is nothing at ali to obstruct the enti ance of the blood. The structure of the pari, the phenomena presented by vivisection, inflation and injection, ali prove the samething. Ibid., n. 147-150.) The venous blood, there re, that is, of the whole body,) is carried with a perpetuat, sWist, and violent motion, from the VenOUS SinUS, through the right auricle, and through the right ventricte, into the pulmonary artery alone. The lest venous sinus receives ali the pulmO- nary blood from the four great concurrent pulmonary Velias, and by iis