Hcemajlatks. 7 3 
teries of living Animals, becaufe the Animal 
mufl: needs dye while it is doing. 
2. The Area of the tranfverfe Sedion of 
the pulmonary Artery, being in one part, be- 
fore it divaricates into Branches, of the fame 
Dimenfion with the Orifice of the Aorta^ 
the Velocity of the Blood in that part, may be 
accounted the fame as in the Orifice of the 
Aorta. But tho* the Qiiantities and Velocities 
of the Blood in pafling out of both Ventricles, 
be the fame, yet it does not thence follow^ 
that their expulfive Forces mufl: be both the 
fame: For if the Blood in pafling into the 
pulmonary Artery, finds lefs Refiftance from 
the preceding Blood, than the Blood does in 
entering into the Aorta^ then a lefs Force 
will expell it out of the right Ventricle with 
equal Velocity 5 and accordingly, as there is 
not fo much Force required to drive the Blood 
thro’ the Lungs, as thro* the reft of the whole 
Body, fo we may obferve, that the Subftance 
of theMufcIeof the right Ventricle, has not 
near the Thicknefs of that of the left. The 
following Experiments and Obfervations may 
give us fome Light into this Matter, ^iz. 
5. I fixed a glafs Tube to the pulmonary 
Artery of a Calf’s Lungs^ and then thro* a 
Tunnel 
