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roady passed through a state of reformation. In tho volns thoblood is everyWhere disrused, and one part is held in separation om another; in the arteries the blood is dri ven to tho axillaryline, so as to sorm as it Were One fluent 1ibre n. 199, IV.). In the vetiis the spirit and the serum aro reunt ted to the blood; in the arteries they are disjoinod, and tho blood iiscis is dividod. Helice arise iis color, brighiness, red ness, coagulabili ty, &c. The fame is observabie in the chicli during iis formation in tho
the arteries Was Os a deep red color; but that whicli returned through the volns had n yelloWish hue n. 242). The more common or generat there re be the artery, the more does iis biood abound in laut heterogeneous elemenis, from Whicli it is clarified in proportion as it is elevated into purer regionS, Ortransferrest beyond the branches leading into the kidneys, liver, and other viscera n. 203).239. Finalty, there is nothino in the whole mundane system more perfeci than man, and vel nothino more imperfect is he abus the faculties designed to be emplayed in mastins him perfeci. In
generat We may Observe that man is an animal machine possess-ing a structure Worthy of Our highest admiration; he is a most
vellous, indeed, that ali nature appears to have unsoldest horsolsin him. In Order the more to see hoW astonishing are his persections, let me recati the attention of the reader to aDW only of Our preceding remartis. I. HoW ingeniousty intho human body is one thing subordinated to another; hosis an imperfeci pari placed under the rule of a more perfeci; sortho vesseis are subordinaten to the fibres, the blood to tho spiri- tuous fluid, tho body to the bratus; While Mon the bratus arebestomen science and efficient poWer. 2. In man, nil thosethings are multiplied Which are more perfeci, and Whicli pertainto causes Or sirst principies. For he has a largor brain, iis divisions are more Ordinate, and the fibres thetice educed correspond in quantity and purity to the superior organigation of thebrain: by these fibres the contained fluid is so dispensed, that ovorything in the body is in subservience to them. 3. There is bustoWed upon the brain a stili more universat sirst principiu
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Linds of insecis, including the silk-worm, that are not furnished witha single heari, but With a number of hearis longitudinalty disposed through the body, and whicli are of the figure of Olives, and Open One into the Other. He Observes, moreOver, that these hearis do not pul-Sate simultaneously, but successively one aster another in their places ;the motion os the first being followed by that of the second, and SO Onin conSecutive Order. Furthermore, that creatures of this kiud do notPOSSeSS compound or collective lungs, situ aled in a gi ven part of thebody, as is the case With the human subjeci, and with numberlessanimais,) but that they have air canals distributed through the wholeb0dy and ali itS paris; . . . a most astonishing device, and at the sirstblusi, weli Digh incredibie. . . . These litile creatures, With their many hearis and weli aerated frames, are everyWhere provided With eXceed ingly viscid liquids, whicli in faci adhere most tenaciousty both to theirparticular organs and structures, and to their hodies generally, at thesursace of Which lalter they either remain at rest or are carried Osr. Hence it is that these liquids can be thrown to onlyJ a stiori distance by any instrument of propulsion, more particularly is impediments Occur in the course of the passage ; for they are separated With thegreatest difficulty froin the sursace of such instrument, and adhere Miththe greatest readiness to the sursaces of ali Objecis in their Way. . . . But since it is requisito that these litile creatures should be recruitedand nourished by liquids thus constituted and distributed, alid sincethese liquids are fitted for their ossices by admixtion With air, henee, precisely in the Same manner as in consequence of their SluggiSh nature, they cannot be derived tuto a single heari, so sor the Same reaS0n they
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structure and motion of the heari and auricles differ at the commencement of generation, and sor Some days asterWards in the Womb, froin the structure and motion of the fame heari and auricles aster generation and out of the womb. But I Will endeavor to explain this incredibie subject in a sew words, in Order that the reaster may under- stand the whole matter With less trouble than he must bestos in consult-ing the treatise of that author. Ρicture then to y urseis a canal With a continuous cavlty, but Os uneques calibre or diameter in disserent paris; and suppose the wide paris Or dilatations to be three in number, and the narroW to be four; then the Whole tength of the canat will be dividod into seven paris, three of Whicli are dilatations, and the other four contractions. The three dilatations, then, are elegantly arranged in the folio ing manner : they do not Succeed each other in direct Sequence, but are eaeli placeu belWeen tWo of the narrow paris, So that one endos the canat is constituted of one of the four narroW paris; thiS partis succeeded by the first of the dilatations ; this, by the second of thenarroW paris ; this, by the second of the dilatations ; this, by thethird of the narrow paris; this again, by the third of the dilatations ;thu series being concluded by the fourth of the narrow paris, Whicli constitutes the other end of the canat. ΝοW What do you thinh theseparis respectively represent i The sirst of the narrow paris is the trunk of the vena cava; the sirst of the dilatations is the right auricle. The Second narrow portion, placed belWeen the right auricle and the secondos the dilatations, is a passage or meatus that conveys the blood fromthe right auricle into the second of the dilatations ; and this second of the dilatations is the right ventricie. The third of the narroW paris, coming after the right ventricte, is a passage or canal that conducis theblood froni the second of the dilatations into the third ; and this third dilatation is the lest ventricie. Finalty, the fourth of the narroW portions, Whicli concludes the series, is the trunk of the great artery. Isthere anything in such a constitution of paris at ali like the heartaster generation and out of the womi, i Here the trunk of the vena cava and the trunk of the great artery are in the fame canal; the lest ventricte, the right ventricte, and the right auricle, are in the fame canal; and as sor the lest auricle, it is Wanting altogether. MOreover this canat is Stightly curved in one portion. The blood is driveu froin theauricle tuto the right ventricte, and froin the right ventricte immediatolyinto the lest, through the narrowed iube sit ualed bet estu the tW0. Sue
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h0W disserent the appearance of the lidari and the motion of the bl00dat the time of their generation, and sor some days asterWardS in the WOmb, Doui the form of the fame heari, and the motion of the blood, after generation, and out of the wombi But diversities and prodigies do not end here. Besore many hours have elapsed, the whole canal, RS far as the litile iube that constitutes the third of the narrow paris, becomeS more bent, and is turned upon itself, so that the right and test Ventricies mutuatly approximate, and in a Shori time come in contact, and the intermediate canat is closed by turning upon itself: and at the Same time the right auricle approaches nearer to the top of the right ventricle untii it comes in contact with it; and the litile iube that constituted the second of the narros paris, is obliterated. Aster this, the pulmonary artery and the pulmonary Vein issue from their respective Ventricles, and the pulmonary vein has iis auricle aflixed to it above thotest ventricie. What an incomprehensibie series of things is heret Vliat incomparabie industry l ΙΙow truly divine a process os fabrication lV Ibid., prop. X., P. 65, 66.)242. ΜΑLPIGIII thus writes On the formation of the chich in theogg. Ier I 2 houra os incubation the . . . partS became more distinctly observabie in the enlarged cicatricula, Whicli rising up ardswas almost horigontal. Thus the follicle or sacculus enclusing the
chichJ having been ruptured, the lalter came in sight With a large headand tWO rows of vertebrae, forming the rudiments of the carina: thatis to say, a series of White orbicular Saeculi representing theSe paris, oros vesicles contiguous to each other, extended downWards, and beset the stamina Of the spinal marrow ; and the sirst rudiments of the brain Were likeWise obscurely visibi e . . . Ainter I 8 hourε of incubation the cicatricula presented no great alteration in structure, but occupied horigon-talty the apex of the ogg. The chich, With a large head and oblongspine, the lalter covered by the ruptured sollicie, Was immersed as heret fore in the colliquamentum, of Whicli the quantity Was noW increaSed . . . . At the end of 24 hourε, ... I thought I could deieci the motion os the heari, although on this potnt I Will not be certain. . . . When 36hOur8 had elaFδed, . . . the head Was plainly seen, turgid With the usual vesicles, and also the rudiments of the Wings, and the Spinal marrOW. . . . Ier 38 hour8 the chicli, increasing in Sige, possessed a large head With three vesicles siluated in it; . . . and was surrounded by certain
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coverings encompassing the Whole tract of the spine, Whicli latior vias composed, as heretos ore, Os the round sacculi of the vertebrae. Abovo the origin of the wings, Ι now for the srst time plainly saw the strueturo of the heari, whicli I had indeod somelimes thought Ι could deieci previolasty ; sor the chich noW being alive, a pulse Was ObserV- le, and When this pulse censed, a Lind of darii line was at last traeed . . . . The umbilicat Vesseis Were seen ramisying about in thecircumference With varicose and reticulated tWigs ; but their productionas sar as the heari Was Dot yet visibie ; for they Were obscured by the
supernatant colliquamentum Or thich Ribumen. . . . Ainter 40 houra . . . the head Was curved; the vesicles of the brain Were not so evident; the rudiments of the eyes appeared ; the heari pulsated, receiving frumthe vetus a rust-colored humor, and somelimes a humor of the color of Sere vine-leaves.' For the externat border of the umbilices ves-Seis Was surrounded by a thich venous circle, Whicli at iis extremiti S . . . Opened into the heart. . . . At first the motion os constrictionobservabie by means of the humor driven through the vetus, Was eVidently into the auricle; hom this the expressed juice Was propelled through a narroWed tubeJ into the ample right ventricte, by the constriction of Whicli it was again protruded into a continuOUS appendage, rom whicli there Was a direct passage into the aorta. The aorta SentupWards certain considerable branches to the head, and was continueddownwards in the forin os a triank, Whicli aster dividing extended as saras the extremity of the carina. Toward the middie region it gave ossilie umbilicat branches, whicli spent themselves by ramisying tWigs in the circumferetice, forming a reticular pleXus, Sueli as Me alWVS See atthe extremities of the rest of the blood-vesseis. A very similar implication or plexus Was observed about the venous VeSSel for circle ; sothat I stili doubt Whether it be a broad vesset, or a conglomerated reticular VenouS pleXUS . . . . I thinh, theres Ore, that these vesicles pulsat-ing in succeSSion, constitute a true lieari, Surrounded as they are forΙ have more than once indistinctly seen it) With muscular fleshy portioris that have not yet taken On Opacity Or redneSS. . . . It iS Very difficult to determine by actuat observation, Whether the exiStence Ofthe blood precedes that os the bes re-mentioned heari, Or vice verSa. For although a dark rust-colored humor is frequently seen in the outer extremities of the umbilicat vesseis previolasty to the heari beoomingobvious to the senses, and it may seem probable that the heari is formed out of a curved and expanded vesset, to whicli fleshy portionS,as it Were hands, are stted externalty ; yet nevertheless, Since at that
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time ali the paris are so mucous, White and pellucid, that use What glaSSeS We may We cannot See clearly into their structure ; and Since, aS may be remari ed in infecis, the structures of the most advancedperiods Os existence have their rudiments in the primordial state ; so I
lidari. But this much certainly is visibie, that the blood or sanguineous matter does not possess froin the commenoement ali those things thatare asterwariis found in it. For at sirst we see in the vesseis a species of colliquamentum conveyed by litile charineis towards the foetus ; after-Wariis, by means of fermentation, a yelloWish εub-vitellinuri and rust- colored humor is produced, Whicli ultimately beeomes red, and in thistast state is put in circulation by the heart. Helice inasmuch as sue-ceSSive changes in the Sanguineous matter are evidenced by the additionos color to the blood, so it may reasonably be doubted whether, in like manner, the eXistence of the heari is not rendered evident by motionalone, and whether the heari, although quieScent, nevertheless maynot have preexisted, but in a motionieSS State, in consequence of iis fleshy fibres not being yet formed. But it Aeetias clear that the ichor, or matter above alluded to, Whicli asterWards becomes red, existes antecedently to the motion of the heari; but that the heari, as weli as iis motion, are antecedent to the rubefaction Of the blood. . . . Affer theta pSe of 2 Jay' . . . the litile fac of the colliquamentum, or theamnion, Whiel, was fuit of a copiolis dark ichor, contained the chich, the vesicles Whereos filled the curving head ; the sacculi of the vertebrae were stili more apparent, forming longitudinat lines ; and the beari, pendulous ori the oulside of the thorax, beat With a triple pulse ; one partos it pulsating aster another in succession : sor the humor it received, and which was in Some cases Os a deeper rust-color, Was Sent by the vein through the auricle into the ventricles, and Dorn the ventricles
into the arteries, and lastly into the umbilicat vesseis. I osten Lepithe chich, and dried the yolk underneath it, and the pulsation of tho
emplied themselves by their last branches into the auricle of the heart. I Was very solicitous to discover What was the first perceptibio forin os the heari; and so sar as the bl od that it containod onabled me tomahe it out, I have represented it in the accompanying figures fig. J5, I 5, i5, 15) : hom Whicli it appears, that the blood is con- Stantly carried into the auricle by the vetiis running froni the border of the umbilicat vesseis , and is expressed by the auricle through a SOme- times stiori intermediate canal into the right ventricle; thurice into thelest Ventricte, and therice again into tho arteries, by Whieli it is transmitted to the head on the one hand, and to the umbilicat vesseis On the
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other. . . . At the end of 2 Jays and id hourδ, the chicli, increasing insige in proportion to the time, Was lying prone, Willi curved head, in the colli iumentum. The Vesicles of the brain Were Observed, supplied with blood-vesseis, together With the rudiments of the eyes ; also thespinal marro running in a longitudinat line, and contained villiin the
tomariis the naiddie of the abdomen, produced the umbilicat arteries and Veliis . . . . The blOOd Was discliarged into the auricle partly froni the extremo border, and froin the ascending and descending vein ; theniaricle then, by iis pulse, protruded it into the rightJ Ventricte, . . . and this, into the nexi ventricte, by Whicli it was sent at last into then orta, to be by it distributed to the head, to the sursace of the body, and to the umbilicus. At the end of 3 Jays, Ι found the chich lying Withiis body curved and turned upside doWn. In iis head, beyond the eyes,
there gere sive vesicles turgid with fluid, Whicli represented the brain. . . . The position and form Os these vesicles Was as sollows : at the topos the head there Was one os considerable sige, furnished With vesseis, and in stippe like a hemisphere, and Whicli, On the Subsequent dayS, Was in a manner divided into tWo; for Whieli reason I am stili in doubtWhether it is to be rogarded as one vesicle at sirst, Or as tWO. In theoccipiat there Was a Lind of triangular vesicle, but the deep region profundum partem of the sinciput Was occupied by an Oval vesicle, close to Whicli vere placed the other tWo, completing the fiVe. . . . The construction of the heari Was as I have here given it; for the mystery of nature, ou Whicli I be re touched, Was clearly resolved in the course of
this day : the auricle receiving the blood froni the Veliis, pulsated Mitha Lind of double motion, as though distinguished into tWo chambers, and thus the blood vas propelled into the heari in a peculiar Way, Whieli requires further investigation. . . . At the end of the 4 fh Jay, theobiek had bdcome more distinctly visible : the brain Was proportionably
very large, and the sve vesicles constituting it Were Stili more conspicuous, and had come nostrer together, and when lacerate J, let out an ichor orfluid . . . . The round bOdies Or saeculi representing the vertebrae Were increaSingly protuberant . . . The cOurse of the Vena cava and aorta Mithinthe body Was concealed, and the litile cord of the umbilicat vesselsissued froni the abdomen ; the blood propelled through the arteries Wasof a deep red color, but that whicli returned through the vetiis had ayellowish liuo. Insido the bodyJ the rudiment of the liVer . . . Wasapparent. In Some instances the heari Was pendulous oti the oulside of the thorax, and iis auricles, brought nearer to it, received the blood frum the vetiis, and supplied it to the ventricles ; for the right ventricle had noW attained iis usual figure, and Was connected immediately to the
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lacerated no fluid now esca ped. The two anterior vesicles of thebrain, less protuberant than be re, Were Somewhat obscured by the incipient gro th of flesti, and the rudiment of the beati Was appendedio them ; the vesicle above and between them in the dees region of the Sinciput , Was almost lost to vi0W, as Was the case also With the fifth vesicle placed in the occipiat. The spinal marro , dividen into tWo paris, and consolidaled, extended longitudinalty through the carina. . . . The umbilicat vesSeis issuing froin the closed abdomenJ wore partly sent to the thin albumen surround ing the yoth and amnion, parilyinto the yolli itself; and the arteries, now diminished in calibre, Were much smaller than the vetiis. In the abdomen the structure of the liver began more olearly to fhew itself. . . . The heari, hidden within the b0dyJ, although in a mucous state, had tWo pulSating Ventricles, from Whicli depended the sineWy auricles, of enlarged dimensiOns and exerting a double motion, and also the coloriesS VeSSelS. . . . At the endos the 7 fh Jay, . . . the head was large and considerabie, and the brainhail become more protuberant, and was contained in the usual coverings,on lacerating whicli, the ichor so lately fluid was found to have concreteilinio solid filamenis, thereby forming the walis and cavities of the ventricies. Between the large eyes the beati gradually manifested itfel . . . The umbilicat VeSSeis, coming OutWariis, Were elongated throughthe yoth and album en . The heari, shut Up Within the thoraX, . . . Was composed Of tWo ventricles, as it gere contiguous sacculi, united together at their upper pari, and with the body of the auricles placedupon the top of them; and there were two successive motioris in the Ventricles, and the fame number in the auricies. The tubular portion, Which by iis pulsations propelled the bl od received from the right ventricle Onwariis into the arteries, was drawn doWnWards, and nOW in- creased the capacity of the lest ventricie ; and both the ventricies Were SuccesSively ensWathed by spirat muscular fibres, connecting Biad encompassing them, and whicli constituted the seshy portion Os the heart. The auricles them selves were uneven and corrugated in conSequence Ofthe interlacing of their sineWy fibres, and constituted as it Were a ne