 In 1937 he was relieved of his professorial duties at Frankfurt (his wife was deemed to be half-Jewish by the Nazis), only to have them reinstated following the end of wartime hostilities in Europe.He is well known for his studies involving the nervous system of invertebrates.He believed in the "plasticity" of the nervous system, asserting that if one part of the brain is damaged, another part could learn the functions of the damaged portion.