‘In the right of man is the liver and its great heat, so that the right is swift to act and to work;[104] but towards the left are heart and lung, which fortify the body for its task and receive their heat from the liver as from a furnace. But the vessels of the liver, affected by the agitation of the humours, trouble the venules of the ear of man and sometimes confound the organ of hearing.... ‘I saw also that sometimes the humours seek the navel, which covers the viscera as a cap, and holds them in, lest they be dissipated, and maintains their course and preserves the heat both of them and of the veins.... But sometimes the humours seek the loins (_lumbos_),[105] which mock, deceive, and endanger the virile powers and which are held in place by nerves and other vessels; in which, nevertheless, reason nourishes so that man may know what to do and what to avoid.... ‘And the same humours go to the vessels of the reins and of other members, and pass in their turn to the vessels of the spleen, and then to the lungs and to the heart; and they meet the viscera on the left where they are warmed by the lungs, but the liver warms the right-hand side of the body. And the vessels of the brain, heart, lung, liver, and other parts carry strength to the reins, whose vessels descend to the legs, strengthening them; and returning along with the leg vessels, they unite with the virile organ or with the womb as the case may be. ‘And as the stomach absorbs food, or as iron is sharpened on a stone, so do they bring the reproductive power to those parts. [Illustration: From WIESBADEN CODEX B, fo. 123 r Plate XXI. THE FALL OF THE ANGELS] ‘Again, the muscles of the arms, legs, and thighs contain vessels full of humours; and just as the belly has within it viscera containing nourishment, so the muscles of arms, legs, and thighs have both vessels and the [contained] humours which preserve man’s strength.... But when a man runs or walks quickly, the nerves about the knees and the venules in the knees become distended. And since they are united with the vessels of the legs, which are numerous and intercommunicate in a net-like manner, they conduct the fatigue to the vessels of the liver, and thus they reach the vessels of the brain, and so send the fatigue throughout the body. But the vessels from the reins pass rather to the left leg than to the right, because the right leg gets its strength more from the heat of the liver. And the vessels of the right leg ascend as far as the renal and kindred vessels, and these latter vessels unite with those of the kidney. And the liver warms the reins which lie in the fatness derived from the humours....