Columbus, therefore, set forth the true course, and in no small degree the true nature and meaning, of the movement whereby blood passes from the right auriculo-ventricular ring to the aorta, and in so doing he expelled important errors from the Galenic system. But, strange to say, by thus purging it he greatly strengthened it, as was mentioned earlier in this paper, for he harmonized the fundamental doctrine of the Galenic system with the true mechanism and working of the cardiac valves, and with a rational theory of respiration.[147] This fundamental Galenic doctrine was the direct distribution of blood to the tissues through the veins from the liver as a center; no more than a fraction of the blood ever passing the tricuspid valve to reach the lungs or to enter the arteries as spirituous blood. Of this doctrine Columbus was not only an adherent, but a warm partisan against the Aristotelians; and, like Galen more than thirteen centuries before, Columbus points with emphasis to the tricuspid valve as evidence of the falsity of the Aristotelian doctrine that crude blood enters the heart to be perfected and returned thence to the vena cava for distribution.[148] The Galenic view that the liver is the origin of the veins and the source of the blood, by which word, unqualified, was meant the venous blood, was known even down to Harvey's day as the view of "the physicians," as opposed to that of "the philosophers," who contended in ingenious ways for the view of the great philosopher Aristotle that the heart is the origin of the veins and the source of the blood. Harvey in this contest repeatedly ranges himself in his writings with the Aristotelians and against the Galenists;[149] we shall see him bring the circulation into play to give very effective aid to the former against Galen himself. Bearing in mind the Galenic meaning of the word "blood," and remembering that, in spite of the weak points in Galen's own armor, he possessed in the tricuspid valve a formidable weapon against the followers of Aristotle, listen to the following passage from Harvey's treatise of 1628. He says:-- "Whether or no the heart imparts anything more to the blood than transposition, locomotion, and distribution, whether it imparts heat also, or spirits, or perfection, must be looked into later and gathered from other observations. For the present be it enough to have shown sufficiently that during the beat of the heart the blood is transfused and withdrawn from the veins into the arteries through the ventricles of the heart, and is distributed to the body at large.