Physician and histologist, born in Petilla de Aragon, Spain. He studied at Saragossa University, and became professor at Valencia (1881-6), Barcelona (1886-92), and Madrid (1892-1922). He was specially noted for his work on the brain and nerves, isolating the neuron and discovering how nerve impulses are transmitted to brain cells. In 1906 he shared the Nobel Prize for Physiology or Medicine.