Page:The Harveian oration, 1875 (IA b22314611).pdf/26

 And here, again, Harvey has to correct the errors of others—of those who alleged that the large foetal vessels which are closed after birth, when the lungs take on their proper function, exist only for the nutrition of the lung; and of others who asserted that the heart of the embryo does not pulsate. This last assertion is plainly false; for he, and Aristotle before him, saw the reverse in the incubated egg, and in embryos just removed from the womb.

In most animals then, and in all up to the period of their birth, the blood passes from veins to arteries by the action of the heart, and it is obvious that, in creatures which have no lungs, one ventricle (the left) would suffice to distribute the blood over the body; but (and here Harvey, as is his wont, personifies Nature), when she ordained that the same blood should percolate the lungs, she saw herself compelled to add another ventricle (the right), which should force the blood from the vena cava through the lungs into the left ventricle. The right ventricle, therefore, may be said to be made for the sake of the lungs, and for the transmission of the blood through them, not for their nutrition: for it was unreasonable to suppose that the lungs