Columbus frequently made experiments upon living animals. He was the first to use dogs for such purposes, preferring them to swine. Book XIIII. of the work of Columbus is upon the subject of vivisection, _De viva sectione_. In this he tells us how to employ living dogs in demonstrating the movements of the heart and brain, the action of the lungs, etc. Columbus was the first anatomist who demonstrated experimentally that the blood passes from the lungs into the pulmonary veins. “When the heart dilates”, says Columbus, “it draws natural blood from the vena cava into the right ventricle, and prepared blood from the pulmonary vein into the left; the valves being so disposed that they collapse and permit its ingress; but when the heart contracts, they become tense, and close the apertures, so that nothing can return by the way it came. The valves of the aorta and pulmonary artery opening, on the contrary, at the same moment, give passage to the spirituous blood for distribution to the body at large, and to the natural blood for transference to the lungs”. Like Servetus, Columbus held to the idea of “spiritus”. Harvey was the first physiologist who recognized the circulation as purely a movement of blood. All before him assumed the existence of a mixture of air and blood. Columbus, pupil and prosector of Vesalius, like his great master, denied the existence of foramina in the cardiac septum. Gabriel Fallopius [Illustration: GABRIEL FALLOPIUS] Gabriel Fallopius (1523-1562), of Modena, was a noted Italian anatomist. In his twenty-fifth year he was made professor of anatomy at Pisa. Although the span of his life was short, he will be remembered always as the discoverer of the tubes which bear his name. According to Fisher, Fallopius “described the ear more minutely than had ever before been done. He discovered the little canal along which the facial nerve passes after leaving the auditory; it is still called the _aquaeductus Fallopii_. He demonstrated the fact of the communication of the mastoid cells with the cavity of the tympanum; and also described the fenestrae rotunda and ovalis. In the treatment of diseases of the ear, he used an aural speculum, and employed sulphuric acid for the removal of polypi from the meatus. In some of his supposed discoveries he had long been anticipated; for example, the tubes which bear his name were known and accurately described by Herophilus, over three hundred years before the Christian era, and also by Rufus of Ephesus, of whom Galen speaks as the best anatomist of the second century. Rufus refers to two varicose and tortuous vessels passing from the testes (as the ovaries were called) to the cavity of the uterus. Fallopius, however, gave a full account of their course, position, size and structure. He cut into them and found them hollow, gave them the name of tubae seminales, and posterity attached his name to them, and in time came to a better comprehension of their true function.