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Show __.__.___‘..~._.__._‘._~~ Ofthc Alt/[ion of the Heart. Bool' ll. the interpolition of {bong ligaments , and by the entercomfe of Fibres, which mutually unite their feveral ranks; So that when the Fibres grow tenle and rigidby the free reception of drops of Blood through their fruit-~ iiil Pores into their inward Compage, theintermcdial fpaces oi the Fibres are lellened 3 and feeing the bodies of the Fibres being enlarged in dimenfions, cannot have tecourfe outward, as being confined by the ambient parts of of the eighth pair of Nerves, Fibres mul't of ueceflitv be more and more drawn inward, as they approach the Center of the Heart, till the Concave Perimeter is {hit leliened and then taken away to dii‘charge the Blood into the Orifices of the adjoyning Arteries, for the fupport oil the whole Body. Farthermore, the Scpmm or Partition-Wall of the Heart, being thick, is not ealily Contracted as made up of many Spiral Fibres, which hinder the motion of its Extremities toward the Middle; 80 that it is more ealie, according to the Mechanifm of the Heart, for the Walls by approaching each fideof the Seplum to lcllen the Cavities of the Ventricles, than for the Extremitics of the Srptum to be drawn toward the Middle. Farthermorc, to illultrate this difcourlE of the Motion of the Heart, I will add, that the outward Perimeter of the Heart being not alternble, as guarded with a multitude of Spiral Fibres and the more inward ranks :10 ‘l 3mg greater dimenfions, by having their lpongy iiibltancc diltended with tliereception of a quantity of Blood, mull be drawn inward by making more Corrugations, as they approach the Center ; whereupon the fphaare relating to the Ventricles of the Heart, mull be lcllened, as being filled up by the enlarged Fibres of the Heart, which being inwardly imitated by a large proportion of Blood imbibedinto their inward Receffes, and outwardly by a comptellion made by a current of Blood bearing upon the Walls of the Heart; do often Contract inward appearing in repeated Vibrations to cafe their Intrals and outward Surface from a load opprelling them, by difcharging it into the neighbouring Vellels. And it is Very con'ipienous that the Motion of the Heart is exerted by Helhv Fibres moving in {err-ml ranks toward the Center (by various Corrugations firaightning the inward Perimeter of the Ventricles,) by making an Incilion into the Ventricles, whereby a Finger being immittecl into either of them, is highly pinched by the firong Contractions of the flelhy Fibres, M .c Heart. 0f the [Motion of the Heart, highly aflii‘a‘ed with great Palpitations, faint Fullhtions, and dillicult Breao thing, canted by the current of Nervous Liquor ( infpired with Animal Spi- the Heart not capable to have their Convex Surface dilated 3 the dil'tended ‘ Book ll. more and more approaching the Center; And it is alfo agreeable to Ocular demonl‘tration, that at the finite time when the divers ranks of Helhy Fibres are carried more and more inward in various Flexures toward the Center, to leil'en the Cavities of the Ventricles, that the outward Perimeter of the Heart is neither Dil‘tended nor Contracted, which I plainly {aw in a Dog Dilleéted alive in the Theatre of the Colledge of Phyficians in London. And the Heart is a Machine of Motion, not as afled alone by flelhy Fi~ res (quid pure (7 prxcife Idler) but as accompanied with Nervous and Ten~ dinous Fibres, which are inferred into, and mixed with Carnous, and are " great Auxiliaries, if not principal Actors in the repeated Syltoles of the it?" 1 This may be Clearly proved by a Ligature made upon the eighth lair or Nerves 1n the Necks of Animals; whereupon the Heart will be i highly 73"- tits) much intercepted in its progtefs toward the Heart by a fitong comprefs The Nervous liquor is enobled with Animal Spirits feared in the Brain,be- ing a fyl‘tem of numerous Fibres, as in a Fountain, from which many conllant fircams of Animal juice are gently tranlinitted through feveral divariv cations of Nerves (relating to the eighth pair and Intercollal Nerves ) into the flelhy Fibres and Tendons of the Heart, which are rendred Tenfe with their Nervous Liquor, expanded and invigorated with the Subtle and Elallick Particles of Animal Spirits, as well as the Carnous Fibres are fwelled with innumerable drops of Vital Liquor, received through many Pores into their l'pongzy fubl'cance, whereby the many Lairs of Helhy Fibres, fal'rned to each other by fl'rong Ligaments, and the mutual union of flelh‘y Fibres ( interceding them) do more and more Contract toward the Center, and caufe the Walls of the Ventricles to make brisk Appulfes upon the Eldod, and by a violent Comprellion force it out of the Cil'terns of the Heart intd the adjoyning Sanguiduéts. The Carnou: Fibres are acted by NCI‘" vous, as cn-r ducdwith PM mmalLiqucr and Spirits, «hence they are remixed tents. |