Zamenhof Day Zamenhof Day Zamenhof Day (), also called Esperanto Book Day, is celebrated on 15 December, the birthday of Esperanto creator L. L. Zamenhof. It is the most widely celebrated day in Esperanto culture. On this day, Esperantists hold information sessions and cultural gatherings to promote literature in Esperanto. The history of celebrating Esperanto on Zamenhof's birthday can be traced back to 17 December 1878, when at a birthday party for his 19th birthday he presented to his friends his "Lingwe uniwersala", the first version of his international language. By 1887, this language had evolved into what is now recognized as
Ludwik Hirszfeld Ludwik Hirszfeld Ludwik Hirszfeld (5 August 1884 in Warsaw – 7 March 1954 in Wrocław) was a Polish microbiologist and serologist. He is considered a co-discoverer of the inheritance of ABO blood types. He was a cousin of Aleksander Rajchman, a Polish mathematician, and of Ludwik Rajchman, a Polish bacteriologist. After attending the Gymnasium in Łódź, Hirszfeld, born into a Jewish family and later a convert to Catholicism, decided to study medicine in Germany. In 1902 he entered the University of Würzburg and transferred in 1904 to Berlin, where he attended lectures in medicine and philosophy. Hirszfeld completed his doctoral