Transnational parallel biographies: the lives of Ludwik Hirszfeld and Jan Czochralski and their contribution to modern European science

The article focuses on the transnational lives of the bacteriologist Ludwik Hirszfeld (1884–1954), who came from a Warsaw Jewish family and converted to Catholicism in 1919, and the metallurgist Jan Czochralski (1885–1953), who was born into a small-town Polish Catholic milieu. Both contributed significantly to their research fields – while Ludwik Hirszfeld discovered the inheritance of blood groups, Jan Czochralski developed a method for obtaining single silicone crystals for microelectronics. They had received their education in German-speaking milieus in Würzburg, Berlin, Heidelberg, and Zurich before World War I, continuing their research during the war, and transferring their knowledge into the newly established Polish state where they both settled after 1918. The parallel biographical approach adopted in this article reveals that the two scientists represent a specific experience of space and time, namely the imperial and the post-imperial space of transition, of mobility and migration, border crossing, and of a circulation of knowledge that can be interpreted as being quite typical for the region of East-Central Europe in the first half of the twentieth century. Their expertise crossed borders and challenged the principle of territoriality, since the personal and cognitive legacy of the empires overlapped with the process of nation-building. In this constellation, the circulation of ideas and models had a potential not only for innovation, but also for conflict.