1000000030

vcins anJ uteries;

the eontm')ile force of thefe

allrirl,'S, the blood \ViII be vigorouny exprctred and

dri"cn into the right ,'cntricle, whieh, upon Ihis eon–

IraEl,on, is rendered flaeeid, empty, and difpoCed tO

adnllt it,

NOlV,

if the right ventricle, thus full of blood, by

the.eontraaion of its fibres, rrefs the blond tDwuds the

apeno,e ag,lin, the VCllOUS blood at the Carne timepour–

ing in; will Jrive ,t back agai n into the ca,'ity, and mil{

it more ,nlimately, till, riling up againll the parietes, it

raife lhc valvulx trieuCpides, whieh are

eonneEled

lOlh' lIelhyeolumns extended on the oppofite fide, as

Ih.t. \Vhen

I.id

quite down, they eannot clofe the pa–

Iietes of

th~

right vennicle; thefe it thruOs towards

Ihe nght .uride, till being there joioed, they 1I0p.lhe

patrage "ery cloCely, and preveot any relurn.

.Ih~

Carne means, lhe Carne blood rifes inlo the

three f<milunar valves, plaeed in the cxtrcmi lY of tne

other mollth, and Iying open tOlhe pulmonary arter)' ;

thefe ii fllUIS clofe againO the fides of the artery, and

leaves a p.lTage into the artery alone: the blood ear·

rie,1 by this a,tery into the lungs, and dillributed by

its branel:es throu¡;h the whole fubflanee thereof, is

firn adm,tted into th extremities of the pul:nonary

vein, ealled arteria venO/Ca; whenee paffing in10 four

large V!trels, wllleh unite together, it is brought to the

left finus venofus, or trunk of the pulmonary vein, by

the force of whoCe mufcu lou! flruaure it is d,iven

inlo tite left venlricle, whieh, on this oeeafion, is

rf–

laxed, and by that m';ans prepared to reeeive il.

Henee, as befare, ir is driven inlo the lefr ventricle,

whieh is relaxeJ by the fame means; anrl by the val–

vulre mitrales opening, ad,nil ir ioto the lefr ventricle,

and hinder ils flux into rhe pulmonary vein : from

henee it is foreed into the aorta, at whoCe orifiee there

are three femilunar valve!, whieh alCo prevent a reflux,

by clofing Ihe fame.

The morion of rhe blood in living animals is attend–

ed \Vith rhe following phenomena:

l .

80rh the venous

finufes are filien, and grow rurgid al Ihe fame rime,

80lh auricles grow flaecid al Ihe fame time, and

bOlh are fi lled al Ihe fame lime wilh blood, impelled

by the eontraElile force of ils

eorrefponde~I

mufeular

venous finus,

Eaell ventricle COntraaS and empties

itfelf ofblond allhe fame lime; and Ihe IWO greal arte–

ries are fillcd and dilaled allhefame lime.

As foon

as the blood, by Ihis conlraélion, is expelled, both ven–

lricles being emply, the heart gro\Vs larger and b,oad–

Up01 which Ihe mufeular fibres of bOlh venous

finufes eonlraa, and expreCs Ihe blood eontained in

Ihem inlo lhe ventride of Ihe heart,

In Ihe

mean time Ihe venOlls finufts

art

again filled as be–

fore, and

Ih~

auricles,

&c,

return inlo Iheir former

hab;lude,

T his altcralion eonlinne! lill the animal

begins 10 languilh u",ler Ihe approaeh of dealh,

which lime Ihe auriel"s ann venons finufes make feve–

ral palp'lations, for onc eonlraaion of Ihe ventricle.

In a fcctus, Ihe appa"lus for the eireulalion of Ihe

hl~od

is fome whal dlll'erent from Ihal in anults, The

feplum, whieh reparates the IWO , uricles of rhe hean,

piereed Ihrough \Vilh

apen ule, ealled the fora,

VOL . ll. No. 38.

men o\', le, an'! lhe Ii'lInk of the pullllonary artcr)', a

little afler il ha. lefl the heart, kilOS Ollt

tube into

the defeending aorta, e,tlleo the cOllllllunll;,,,;ng canal.

The fertus being bnrn, the 1"ramcll (J\'alr. clofes by

degrees , and Ihe canal 01' eommunication nrles ur, and

beeom-!s a Gmple ligamenl.

As 10 Ihe veloeil)' of thc eirculaling hloo'l, ami th..

lime IVherein the eireulalion is eompleted, fc\'rral eom–

pUlalions have been made, By Dr ICeil 's aceounr, tI,e

blood is dri,'en Ollt of theheart into Ihe aorta Wllh avrlo–

eily whieh would carry it twenty·five feer in a mioute:

bUI Ihi, vdoeity is eoolinnally ahated in Ihe progrd;,

of Ihe blood, in Ihe nl1meruus feaions

01'

branehes

Ihe

artrri~s,

fa Ih,t beforc it arrive al the extrtlllll'CS

of Ihe body, its mOl ion is greatly dillliniflled, The

fpaee of time ",herein thc whule mars of blooJ ordina–

rily eirenlms, is v"ioufly determined,

SO'Tl~ II'I~

Ihus: SUjlpofing Ihe hean to make tl\'Odiol1 lancl pnlfe '

in an hour, ann Ihat al en ry pulfe Iherc " exl'cl kc\

an ounee of blood; as Ihe whole mafs of bluod IS not

ordinarily eomputed 10 exeerd I\\ enty.fou r pUI,nds, it

mufl be eirculaled feven or cight times over in

th~

fpaee of an hour.

T he eireulalíon of the blood was lirn difeo\'cred in

England, in Ihe year

1728,

hy Dr Harvey.

CtR CU LATlON

o/Ih, /np o[

vrg(lnb/a,

See Vol.

45 ·

CIRC ULA TION, in eheminr)', is an operariol1 "'herehy

Ihe fame vapour, r.ired by lire, f,dls

b.rk

, tO be re–

tarned and dillilled feveral limes.

C'RCU LATION

o/ilion')'.

See COMMHCE, and Mo–

ClRCULUS, in ehemiflry, an iron innrumeO! in f01'l11

of a ring, whieh bcing hemd red hot, and applied lO

Ihe neeks of relons and olher glafs v¡trels, lill Ihey

grow hOI, a few drops of eold water Ihro\Vn "l,on

Ihem, or a eold blalt, will make the neeks fly regu–

lady and evenly olf.

Another method of doing this, is to lie a threan,

firn dipl in oil of IItrpenline, rOllnd Ihe rlaee where

you would have il break: and Ihen fe!ting fire tO thc

Ihread, and .fterwa,ds rprinkling the place ",ith eold

waler, Ihe glafs will crack exaltly where Ihe rhread

IVas lied.

CIRCUMAJENTES MUSClILI, or OSLqy l 1I1 us.

CUL I, in analomy. See Vol.

29P.

CI1( CUMAMl3lENT, an 'ppellaliol1 giv"n 10 .

Iltin~

thal furrounds anolher on all rldes; ehielly ufed in

fpeaking of the air,

ClRCUMCISlON, Ihe ..a of eUll ing

cIIl'

:ile

pr~pucc;

a eeremony ,n Ihe ,lewlOI and M,lltom",etan Idig;oo"

wherein Ihey

cut

01T Ihe foreÓlin of d,eir m. les,

are 10 profefs Ihe one or the olher la",.

Among Ihe Jews, thetimefor performiog Ihis riteWJS

Ihe eighth day, Iha! is,

fix

full

aftcr th: ehild

\Vos

barn: Ihe law of Mofes onlained ootlting with rdpl el

to thc perfon by whom, the inllrllmll1t wlrh \\ Itirh, or

I',e m.l1ner how, the ceremony was to

O"rOI

Oled ,

Ihe innrumenl \Vas generally

knifeofnone: T he child

is ufua l1yeireuOleifed at home, whelc ,he f. ther.

nI'

gonfadlcr, holJs Itim in his arms, \l1"le the v:'er"'r

1.,1,.',