| OCR Text |
Show 0f the Motion of the 73100:]. Book ll. impulfe imparted to them from the Syllole of the Heart; and alfo beciufe the extremity of the capillary Arteries are very narrow, and do not eahly admit the cxpulfion ofBlood into the fubfiarrce of various parts, relntrng to the Body; Therefore Nature hath molt wrfely COflfl'lVCtlh fomc other Machines of Motion (feared in the Blood-Vellels) as ltuxuiaries to the Fibres of the Heart, to allilt the impulfe of the Blood, derived from the Syfiole of the Heart. It is molt evident, that the Arteries being foft membranous Tubes,are apt to be exPanded, as acquiring greater Dimeufionsin breadth, canfed by the immillion of fome Ounces of Blood into their bofom ( in every Syllole of Henry Fibres are (rated in the Serigui- dufls. the Heart) which cannor be difchargcd by the innate motive power of the Blood: Therefore the All-Wife Protoplafl: hath made External Agents to give an impulfe to the Blood, fir-ll communicated by the Fibres of the Heart, and afterward aided by little fine Organs of Motion ( feared in the Coats of the Sanguiduéts) which are long and circular {iel'hy Fibres, con- tracting and narrowing the Cavities of the Arteries, by bringing their infides Clofer to each other; Whereby the current of Blood is quicltned by the Comprcflion of the Velléls, by caufing one part of the fluid Compage of Blood to ptefs another forward, and fo make good its Flux and Reflux , from and to the great Blood-work of the Heart, by various pipes of Arteries and Veins. l humbly conceive the contraétion of the Blood-veflels, in order to pro- II the Motmn riftlic At re. "(5. The ininixer how thC Blowl is inr piled turnugh the Arteries. The Heart ic- femblctha Pump, in rimming Blool Into the atlzscent Sauguniuélsr mote the Flux and Reflux of Blood, is celebrated after this manner, The Arteries being dilated by the tranfmiflion of Blood into their Cavities, their diftended Coats made up of nervous and flefhy Fibres, are irritated, as having their tender Compage enlarged by a quantity of Blood, fo that the flelhy Fibres finding themfelves aggrieved, do contract and leffen the bore of the Arterial Cylinders, and by comprefiion do haften the current of Blood, by making one part of this fluid Body crowde another forward. The Heart after the manner of aPump, throweth out of the Left Cif'cern, a quantity of Blood, every pulfation,into the Cavity of the Arteries, whence they grow dilated, and thereupon the Motion of the Blood would be interccpted, or much retarded at leaf}, did not the Heart and Arteries by a joynt confiriftive power of their Fibres, countermand the refillance ofthe Blood, made in the expanded Arteries, efpecially in the afcendent Trunk of the Aorta, and Carotide Arteries, Where the weight of the incumbent Blood maketh a high oppofition to the impulfe of the Blood, immitted every Syllolc, firlt into the common Trunk, and afterward into the altendent Trunk of the great Artery; Whereupon it is very requilitc that the Arteries {hould have their Coats furniflred with circular Fibres, that by their Contraétions they might aflill: the Conflriélive power made in the 16ft Ventricle of the Heart, whereby a quantity of Blood is firl't thrown into the common Trunk,and aftei'Ward carried upward, and contrary to the inclination of the Blood, ( as a heavy Body ) by the contraéted circular Fibres of the alcendent Trunk ofthe Aorta, and Carotide Arteries, into the membranes and fubltance of the Brain. Furthermore it is very needful that the Blood tranlinitted into the common Trunk of the Aorta, by the power of the Heart, {hould be feconded 13021; ll. 0f the [Motion of the Blood. 74-3 the fmall and faint vital f'treams cannot pafs through the lnterftiees of the Vellels, unlefs their palfages, much comprefled in the Mufcles, and Farmchyma of the Vifcem, be dilated by a. new impulfe of Blood, imparted to thy the contraction of the circular Fibres, relating to the Arteries. And the narrownefs of the bore of- the capillary Arteries, and of the Llor (1 north grow full" m At- terrc ditlaut From the Heart, were it not h:lp,d by t c con~ their Terminations, and the firaitnefs of the palfages between the lnterl‘ti- "no . ces ofthe Velfels, do makea great refillance to the impulfe of Blood, open- 0 ing the Paifages and Pores of the folid part, which are not only fmall, but have divers Figures like a Sive, through which every particle of Blood infinuating it felf, receiveth alike Configuration, as Honmgenwm , nt [male :1 zmili nurriamr ; f0 that the Pores being prepoffelfed by the impelled nutricious parts of the Blood, do exclude the Exerementitious Atomes, from being admitted into the Pores of the folid parts. And farthemore , the impulfe of the Blood coming originally from the Syflole, is promoted by the contraéted circular Fibres, feared all along in the Coats of the Arteries, that the Motion ofthe Blood may be continued through the finall capillary Arteries, and their terminations inferted into the cutaneous Glands, wherein a fecretion is made of the Recrements (from the pure parts) which are carried off through the Excretory Dué‘ts of the Skin by Sweat, and infenfible tranfpiration. And I mol't humbly conceive, that there is not only a conltriétive Power feared in the Arteries, but in Veins too, which are accommodated with circular Fibres (plainly difcernable in the Trunk of the Vemz C4716! ) by whofe Contractions the Blood received into the extremities of the Veins ( of the lower Limbs and Mufcles, and Vifcera of the lowelt Apartiment) and afterward tranfmitted by their greater and greater Branches, and the Trunk of the Vemt Cow, into the Right Ventricle of the Heart; fo that the new current of Blood paffing out of the Terminations of the Arteries, Firll, into the Interltices of the Velfels, and afterwards received into the Veins, could not over-power the refiftance of the weight of the incumbent Blood, (feared in the afcending Veins) by virtue of a. former Impulfe given to the Blood by the Syfiole of the Heart, and Arteries, unlefs it were aéted with a new impulfe, made by the confiriétive power of the circular Fibres, forcing the Blood upward (contrary to its innate difpofition to move dovvnward, as t The Veins have a tor.- lhiftlvc pow er a: well as themmrzsv The Motion ofthe Blood upward, tovsard, and inn to the Herd, isaflifletl by the torllriéL ivc power of the Veins. a weighty Body) through the Veins of the lower Limbs, and Mufcles, and _Vifccra of the lowef't Venter, and through the afcendent Trunk of the Cow, Into the larger Cillern of the Right Ventricle of the Heart. Perhaps fome may objeé't againfl: this Hypothefis, by reafon the Valves are feared in the infide of the Veins, to aid the progrefs of the Blood, tend- ing ‘0 the Heart, left it {hould make a‘ retrograde Motion toward the Origens of the Veins; To which I take the freedom to make this Reply, that the Valves are not quicient to make good the Afcent of the Blood, throngh the afcending Branches and Trunk of the Caz/a, and through the Branches of the Juggulars, and defcendent Trunk of the Calm, when the Impulfe of the Blood, caufed by the Syftole of the Heart, and Arteries, groweth faint in the Termination of the Carotide Arteries, and Interltities of the Vefiels of the Membranes, and fubfiance of the Brain; fo that when the Blood is received into the Veins at a great diltance from the Heart, it is neceffary that that the flow Motion of the Blood toward with another new force, carrying the Blood through greater and lcfs the Heart, {hould be hightened by the Gantraé‘tions of the circular Fibres, branches, and capillaries of the Arteries, (wherein the impulfe of the Blood given by the Heart groweth Languid ) through whofe minute terminations, mmmpafling the Veins, iceing the Valves of the Veins do only hinder the the The Morita", E9 Mariam TheVah'e: ofthc Vein are not Huh. cicncro malt! good (he Aftent of the Blood rnistrd (L: Heart. |
