HEART. 
aancalid is more capacious than the left; but, thi point ee 
been controverted. Anatomilts have endeavou 
the ors w ‘dl be oe largeft, if the animal & fo illed as to 
roduce aco ngeilion on spat fide, and liberate the right. 
The flethy fibres of the ventricles are very elofely arranged, 
_ ¥fo thatthe heart contains a patie quantity of fibres, under 
.a given bulk, than any other muicular organ in the body. 
-Thefe fibres are connected by.a very fhort and.denfe cellular 
fubltance ; are not ealerias into diftin® fafciculi furrounded 
by 2 tooiie an edium, as.in other mufcles-; and are inter- 
ywoven with werk other in fe inextricable a manner, that the 
feription of pared civetion and arrangement becomes very 
difficult. re. all more or lefs oblique, but in. fuch a 
manner. that Sra: approach more-nearly to the tranfverfe 
‘than.to the Jongitudinal dire€ticn ; and none extend  direcily 
_ from the baiis to the apex of the heart. . Their origin cannot 
be fettled :- 
-bafs to set apex of the heart : and their.infertion is equally 
uncertain... They arife from all points of the furface of the 
veatricloes and they feem to terminate as generally. Thofe 
of the two fides decuffate. at acute angles in the - feptum. 
‘Towards the 
y ‘golumas. already _ deferibed. The fibres of the 
a are every where.to clofely connected, that the va- 
which they form cannot, be feparated and unco- 
eae ah lens lacerati ting them con fiderably. 
The fi f th 
brane, which. is m in a very 
thin flate, much thinner indeed than uponthe auricles. Its 
external {urface is fmooth, conflantly moiftened by a ferous 
th 
ernaerecd§ 
a delicate mem- 
ya 
“de wxfaition ‘of the pericardiu 
r 
auricles-than on the ventricles. It hardly. ane in, te heart 
of the foctus; and fometimes is not obferved at all.on the 
ventricles of, fubjedts three or four Years ok oat becomes 
depofited more es in life ; 
“-and is abwaye: feen in cotdeble mene nolan SOON It 
- varies coniiderably- in younger individuals, 
ree from fat soe the fubject has ban 
aoe or. anafarcous, a as ices jon 
. cavities of the sventricles are lined. by continua- 
inner furface. 
<i _arile. 
they are not.continuous ‘in their courfe from the 
on the’ 
in the 
all the proje&ting columns, and Po ae into the excavations 
tween. thele. 
The arteries of the heart are two in number, and named 
the coronary: they are the two firft branches of thea 
‘ing about pprandne to the loofe edges of the 
The exa¢t fituation of their origin has been much difputed ;.- 
ther rai the heart than t the finufes of the anterior ad ‘ 
terior valves, in which cavities fome 
In the dead fubjec it is not, eafy to extend the valves 
fufficiently to cover the openings of thefe veflels. The cal- 
lous white line, which bounds the upper edge of the val- 
_vular finufes, and correfponds to the loofe edges of the 
valves,.is place under the orifices. of the cor onary: arteries, 
If the aortic valves covered thefe openings, the coronary arte- 
ries would receive their blood at.a different time from the 
other branches of the aorta; the blood paffing through the 
- aorta wouid prefs the soir again{t the fide of the cane and” 
clofe the coronary. arteries, which mutt therefore he filled 
by the retrograde blood, aid confequenily have se ftream 
of blood accelerated, when the heart-i is dilated. »Now this 
is not the cafe: we can eah ly fee in hivi ing animals, « that the 
veflels of the heart pulfate-with the onlen:-aat 3 and. if 
eries 
one of them be opened, se jet of blood is increafed when 
the heart contraéts, and: fa : is dila’ 
(Element. Phytfiol. lib. 4, fe€t.. 3, §.30.) The diftribution of 
thefe ares is defcribed in the article ArTERyY. veins 
of the heart, of which nearly the whole unite into:the great 
coronary vein,-which opens into the right auricle, are de- 
{cribed under -Veu. It has been afferted, both of the CO" 
ronary arteries and veins, that many of their minute brane! 
and particularly thofeef the-latter, open on the funkacetl 
the various cavities, efpecially of the auricles. This was 
firtt ftated by Vieuffe tery oF 
Thebefius wrote a particular work on the fubje, “and the 
openings in queftion have nneines been named after hi 
foramina Thebefii. Senac, Duverney, and others affert 
on injethed fluids will not take this pwd Haller 
ternal furface of - ate 
ferences concerning the fate of 
of which, howev ver, we have no dire& ie 
‘he heart and pericardium have numerous abicsbing 
fels,. he take up the fluid Fdepabtes py the- paar > 
hat. mem o not know whether — abforb any 
son the internal Facace of the caviti 
ing 
: The nerves of the heart are derived from the par mg 
parts 
fait are diftribut ted upon the aorta and the coronary arteries. 
Hons of the membranes whi h cores Seopa te 3 £ See Nerve, 
—— icles, and sind eribed-in . Fetal Heart This-or -of the fr vifcera Seen 
pgaparsies caeas —_ gan is one.-o: - 
—— . “ see — -o - — two. eating ff in the embryo, as we find in it ee caufe wb be ise = te 
Tt is moft clofely . oe to the furface- of. 
nice fibres, both in the. ventricles and auricles, , by. ra 
fine and fhort cellular fubftance, in. whicha no; fat: is ever ob- 
ferved, The extent of the “membrane is. le.-as. 
itis folded to form the dif covers 
figned to give a fmooth furface: for the paflage of 
circulation, and confequently. the The mao 
formation growt ms nsrhnen t ot parts 
i Haller, ceived at the end of the decond: day’ 
pap tans Bo Fuck, on pa time white ak colourlelty i 
difcovered by the alternate rifing and falling, to be de ee 
hibits. itszconical figure, firmnefs of ftruGture and irritable 
lity,-. and. ean shiento: to ‘il tbe thee: whe ee 
have itated that they - 
Bs Se wiaeee® 
dita 
vis = 
nad PRM Ciba 
TE PDs ae eRe ns ee 
pe Leet Sey eee tan 
