Fabricius, Geronimo. Latinized name of Girolamo Fabrizio (1537-1619)

Italian anatomist and embryologist. He made a detailed study of the veins and discovered the valves that direct the blood flow towards the heart. He also studied the development of chick embryos. Fabricius also investigated the mechanics of respiration, the action of muscles, the anatomy of the larynx (about which he was the first to give a full description) and the eye (he was the first to correctly describe the location of the lens and the first to demonstrate that the pupil changes size). Fabricius was born in Aquapendente, near Orvieto, and studied at Padua, where he was taught by anatomist Gabriel Fallopius. In 1565 he succeeded Fallopius as professor and remained at Padua for the rest of his career. Fabricius built up an international reputation that attracted students from many countries, including William Harvey. Fabricius publicly demonstrated the valves in the veins of the limbs 1579, and in 1603 published the first accurate description, with detailed illustrations, of these valves in De Venarum Ostiolis/On the Valves of the Veins. He mistakenly believed, however, that the valves' function was to retard the flow of blood to enable the tissues to absorb nutriment. In his treatise De formato foetu/On the Formation of the Fetus 1600 - the first work of its kind - he compared the late fetal stages of different animals and gave the first detailed description of the placenta. In De formatione ovi et pulli/On the Development of the Egg and the Chick 1612, he made some erroneous assumptions; for example, that the sperm did not enter the ovum, but stimulated the generative process from a distance.