The question was, what became of it all?
For it should be remembered that the return of the blood by the veins was unknown, and nothing like a "circulation" more than vaguely conceived even by Harvey himself.

Once it could be shown that the veins were constantly returning blood to the heart, the discovery that the blood in some way passes from the arteries to the veins was only a short step.

Harvey, by resorting to vivisections of lower animals and reptiles, soon demonstrated beyond question the fact that the veins do carry the return blood.

"But this, in particular, can be shown clearer than daylight," says Harvey.

"The vena cava enters the heart at an inferior portion, while the artery passes out above.