denied, that the Intercostal Muscles and Diaphragm are of great service to aid and facilitate this Contraction, by opening a Passage for the Blood through the Lungs, which denied would be an invincible Obstacle.
Neither do they promote it that way only. The manner how they farther assist the Heart in its Contraction, will appear manifestly, if we consider the different Posture, Situation, and Capacity of the Blood-Vessels of the Lungs in the several times of Elevation and Depression of the Costæ.
The Pulmonary Artery rises from the right Ventricle of the Heart, and runs in one Trunk, till it comes to the Aspera Arteria, where it is divided, and sends a Branch along with each Division of the Aspera Arteria, according to all the minutest Subdivisions, of which it is likewise subdivided, accompanying all the Bronchi, in their whole progress through the Lungs.
The Pulmonary Vein, which empties itself into the Left Ventricle of the Heart, spreads it self on the Aspera Arteria and