Fabricius, Hieronymus

Italian anatomist and embryologist. From 1574 he made detailed studies of the veins and blood flow and discovered the existence of one-way valves that direct the blood 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).