HEAR A 
yet they are produced by the cellular sei 
ul 
aw 
The rocefs of nutrition fuppofes the exiftence of exha- 
lants in the arteries; but there is no reafon to believe that 
they open on the interior furface of thefe veffels. 
Bichat conceived that the empty ftate of the arteries after 
. death arofe from the abforben: s continuing to act longer than 
the other parts, and e experiments to elucidate the fub-. 
ject. He inclofed blood and other fluids between two liga- 
tures placed on the c carotid ; but ‘did not difcover 
The firft portion of the red-blooded circulating fyftem, 
(the pulmonary veins,) receives almoft exclufively cerebral 
n ived from centre of the 
and in more from the former 
than from the latter. The arterial fyftem is fupplied almoft 
exclufiyely from the ganglia, and the particular mode will be. 
rteries ; thofe of the veins and heart will be examined 
a persed Elatticity, which is obfcure in meft other 
tiffues, characterized generally by confiderable foft- 
a 
fubfe 
anim: 
nefs, Is_ very remarkable in the arteries ; and this p 
In confequence of this property, an artery,. 
when cut acrofs, in the dead fubje&t, prefents a circular area, 
nd this diftinguifhes it from a vein, des of which 
collapfe. The aorta indeed, and fome of its larger branches,, 
may occafionally prefent an ov. appearance, when thus 
cided, from “th preffure of the furrounding parts. 
Their elaiticity enables thefe veffels to reftore themfelves 
atter their fides have been prefled together; or when the 
whole tube has been bent. By enabling the veffel to give 
bin when the blood is thrown into it, this propert 
ne locomotion confec ; 
and provides for the rettoration of the tubes to its former 
. ced - 
af Toperties refilting from the Organization of the Part.—: 
uh. £ lt » Tete mutt be clas ae of 
view? ait, as it ats in the tranfverfe; and, 2dly, in the longi- 
tudinal diveAign Fay ed apt 
of thefe ways, 
matters 
eet 3 
.. Batural calibs the force ‘the two 
"BAST Coat burft, and the cellular covering forms a cyft; in 
or an artery, re 
ly ‘diffeéted 
“death depend on the quan 
y. con 
the contraction of the heart ;, fy 
fhort, the effect is reprefented by fome as exaétly analogous to. 
what occurs in aneurifms. When a lar is tied ina, 
living animal, the blood, ftrongly Si aeetied agent the liga- 
ture, muit exert a dilating force on the arterial parietes, yet 
there is hardly any fenfible dilatation. The arterial tiffue 
will yield, if the diftending power be applied more grz- 
dually ; 
the arterial tubes inthe tranfverfe dire@tion in the livin body, * 
fuby a 
. Hunter, “cut off a portion of about 
an inch in length, from the afcending aorta, at half an inch 
this effet.’ On the Blood, p. 112. 
_ Extenfion in the tranfverfe direGtion is refifted by the 
fibrous coat, and in the longitudinal by the internal and cel- 
lular covering. 
2dly. Contradility muft be confidered, like the preceding 
property, in two points of view. It is much more ftron ly 
marked in the tranfverfe dire&tion, than the extenfibility. 
en an artery is no longer diftended by blood, it contraéts. 
proportio i 
lowing phenomena by this general law. 1{t. The ‘du@us 
i umbili ies g ly contraé after 
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two animals of equal ftature deftroyed, the one! 
fame differ- 
veffels at the time of death. He 
them artificially, deftroys thefe differences, If the 
imeafurement 
He removed from the 
arteries, and meafured ¢ 
