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pafles continually from the Heart into the Trunk, not 
being capable to return back, becaufe of its Valves, 
muff out of neceffity dilate this Trunk more than the 
other Arteries, in which the Blood paffes in an equal 
Paflage; 
And that which perfwades me that there doth not 
go into the Lungs of this Animal, more Blood than 
that quantity which the Pulmonary Branches can admit 
by theii fmall Diameter, and not the quantity which the 
Diameter of their Trunk could furniQi, is, that the Pul- 
monary Veins, which bring back all the Blood of the 
Lungs into the Left Auricle of the Heart, have not ei- 
ther of them entirely two Lines Diameter, which is 
very proportionable to the bignefs of the two Pulmo- 
nary Branches of the Arteries. 
The fecond Artery which goes out from the Baps of 
the Heart, is that which I call Aorta, pniftra : It afcends, 
as it comes out of the Heart, together with, the Left 
Pulmonary, till they have pierced the Pericardium 5 af- 
ter which it makes a large turning, without any fupport, 
towards the Left Side, which gives it the liberty to 
extend itfelf when the Animal ftretches out of its 
Shell, and to refold itfelf when it retires into it; after 
thar, this Artery detcends againft the Back, where it gives 
fome fmall Branches to the Medulla Spinalis ^ after that, 
it returns through the Lungs into tne Abdomen , and it is 
here that it produceth a confiderable Branch, which di* 
vides into two, of which one diftribuced to the Li- 
ver, the Stomach, and the Inteftines, and the other 
turning towards the Right in the middle of the Abdo - 
men, unites to the Aorta dextra $ fo that thefe t wo Ar- 
teries are but one and the fame Branch divided into 
two. This fame Aorta pniflra continues afterwards 
to the lower Belly, to be diLtributed to the Kidneys, 
Thighs, and f he Parts that are below. This Left Aorta 
is much longer than the Right, becaufe of the great 
Circle 
