Page:The Harveian oration, 1875 (IA b22314611).pdf/32

and the removal of tumours. When a butcher, again, cuts the throat of an ox, the whole mass of blood will escape in less than a quarter of an hour and when an artery only is divided, the same thing happens, the blood spurting forth abundantly, impetuously, as if propelled by a syringe. But if the butcher did not cut the ox's throat, after he had stunned it, till the heart had ceased to beat, he could not bleed the carcass effectually.

That the arteries receive blood from the veins no otherwise than by transmission through the heart is proved by the simple experiment of tying the aorta at the base of the heart, when, if the carotid, or any other artery, be opened, it will be found empty, while the veins are full. And now we see why, after death, the veins contain so much, and the arteries so little, blood; the right ventricle so much, the left so little; facts which probably led the ancients to believe that the arteries (as their name implies) contained, during life, nothing but spirits. Harvey surmises that this is due to the fact that the action of the heart outlives the movements of respiration, so that blood is sent to the body, while none is received from the lungs.

At this point Harvey makes a direct appeal to