( 6 7 )

lhar-p Pen-knife, this second Pair os Bellows was tfiov’d very quiclc, wbere-by the firstPair was always kept füll, and always blowing into the Lungs ;by which means the Lungs also were always kept very füll, and without anyMotion, there being a continuäl Blast of Air fordd into the Lungs by the firstpair of Bellow?, supplying it as fast, as it could find its way quite throughthe Coat of the Lungs by the small holes prick’d in it, as was läid before.

This being continu’d sor a pretty whiie, the Dog, as I expectcd, lay stili, asbefore, his Eyes being all i he time very quick, and his Heart beating very regu-larly : But upon Leasing this Blast, and lüffering the Lungs to fall and lye stili,the Dog would intimed ately fall into dyingConvulsive Fits; but be as soonreviv’dagain by the renewing the fulnttfs of his Lungs with the constant Blastof fresti Air. Towards th<.. ktter. end of this Experiment a piece of theLungs was cut quite off ; where’ttfas obscrvable, that the Blood did fredyCirculate, and pass thoroW the Lungs, not only when the Lurgs were keptthus constantly extended, but also when they were lüfkr’d to sublide andlye still. Which feem to be Argumen s, that as the bare Motion of theLungs without fresh Air tontributes nothing to the Life of the Animal, hebeing fouad to sorvive as well when they were not mov'd as when theywere; so it was not the subsiding or movtlessness of the Lungs that wasthe immediate causc of Death, or the stopping of the Gradation of theBlood' through the Lungs , but the want of a sofficient fupply of FrestiAir.

VI, Dr. Tbrufton asterts the chief use of Respiration to consist in main-taining a due Motion of the Blood; But the Arguments he produces to fc_y/>.wi!l.Mus-make out his Astertion fteming to me Infufficient, I pitch’t upon thefollowing Experiment, which I hope will beDecisive of that Matter.

I took a large, middle-aged, heakhy Dog; and, having freed the Tra-chea ffom the adjacent Parts, cut it off just bencath the Tonum Adami , andturned the loose end out ward. After some time allow’d him to recover theprescntConcern; with a Cork, got ready on purpole, I flopt up the Tra-chea, binding it dose to the Stopple. Some few but violent Struggles stic-ceeded; in. which the Sternum was railed, as in the deepest Inspiration ; andthus he dy’d< From thestoppage of his Breath, to the last motion I coulddilccrn in a hy part of his Body,, was, from a Watch, cbstrv’d to be thefpace oftwo Minutes.- I thenimmediately threw open the Thorax ; where Ifaw the Blood stagnating in the Lungs ; the Arteria Tulmonaris, the rightFentrtcle of the Heart. with its appending Aufide, and the two great Trunksof the Cax>a, distended with Blood, to a degree excellive : The Vena Ttd-mwalis, lest Auricle and Ventrtcle of the Heart , in a manner empty; notcontaining (as nearaslcanguefi) more than oneSpoonful of Blood.

This Experiment proves, That Rijpiration promotes the pallage ofthe Blood thro’ the Lungs ; and in Bodks füll of vigorous Blood, itis, on this Account, of pcrpetual necessity. This Acceleration of the

Blood in that pasiage, seems

to be the pfincipal use of Respira'ion\K x iso