Book Description

Excerpt from The Man Who Discovered the Circulation of the Blood The oldest idea of all was that only the veins contain blood, the arteries air. Galen had corrected this latter mistake by tying a cord above and one below a length of nrterv and cutting out the piece nimve and below the ligatures: blood, of course, and not air was found inside. It was thought that blood went up and down the veins like the ebb and flow of a tide, that crude blood was made in the liver and taken to the heart to be purified. The heat supposed to be produced in this process was. Believed to make it necessary to cool the heart by drawing in air in the act of breathing, and this was regarded as the function of respiration even as late as the time of Heller, that is, the middle of the eighteenth century. The pulse or opening up of the arteries was te garded as an active thing on their part, blood not being forced into them by the heart but drawn into them hiv their own suction like o bellows draw in air. But Harvey said the heart is the pump, and the arteries are filled by its forcing its blood into them. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.