Louis Émile Javal of text, but make short rapid movements (saccades) intermingled with short stops (fixations). Javal's observations were characterised by a reliance on naked-eye observation of eye movement in the absence of technology. Javal's interest in strabismus was due to the disorder affecting his father and sister. Javal himself had heterochromia. At middle-age Javal developed glaucoma, and by 1900 was totally blind. He was a friend of Ludwik Łazarz Zamenhof (1859-1917), the inventor of Esperanto, and he stressed the importance of learning this language by the blind. In addition, he was involved in social reform issues that included education and circumstances surrounding
Ludwik Krzywicki in the organization and management of scientific bodies. He served as vice-director of the Central Statistical Office, taught at the University of Warsaw (1919–36) and other institutions of higher education, and directed the Socio-Economic Institute. During World War II he was injured during the defence of Warsaw in September 1939, and the bomb that destroyed his apartment also caused the loss of most of his papers and manuscripts. His working conditions worsened and he died of heart disease in 1941. Ludwik Krzywicki Ludwik Krzywicki (21 August 1859 – 10 June 1941) was a Polish anthropologist, economist and sociologist. One of