“The lecturer’s hawk eye fell on my blue bows in my hair and I hear the question.  Can my friend in blue ribbons remind me of what I talked about at the last lecture?”- recalled years later then student Bogusława Benendo-Kapuścińska her first contact with Professor Ludwik Hirszfeld after the Second World War (1884-1954). The fame of this researcher went far beyond the university, although it was his students’ attachment and admiration that saved his life during the Second World War.

Hirszfeld, as a world-renowned doctor, immunologist, bacteriologist, and the founder of a new science – seroanthropology – was considered to be one of the last great discoverers. He contributed to the division of blood into groups – 0, A, B and AB or the discovery of the cause of the serological conflict, for which he was nominated for the Nobel Prize in 1950.

Conducted his innovative research both before and after the Second World War, he had to go into hiding because of his Jewish origin during the German occupation. In his memoirs published in 1946 (The Story of One Life), he described in detail who helped him avoid the Holocaust. It is an exceptionally long list of workers, peasants, townspeople, intellectuals, landowners and priests. As Professor Hirszfeld, in hiding, with a passion worthy of a researcher, conducted sociological observations on the attitude of Poles towards Jews and on Polish-Jewish relations, the value of his testimony is even more enormous. He devoted many passages of his book to those issues, trying to present his analyzes and reflections very objectively, without aversion and hatred towards Poles. As he himself said, during the occupation “we were clearly lucky in our misfortune: we only met good people.”

It is significant, that he never gave the name of the key figure saving him from the ghetto, however mentioned him four times in his memoirs. Being aware of the criminal actions of the new communist authorities, probably from caution, Hirszfeld preferred not to reveal the personal details of this person, writing mainly about the Potocki family in general. Only in 2018, when the book by Urszula Glensk The Hirszfelds. Understanding the blood was published, this mystery was solved, although until now little is said about it.

The savior turned out to be a Warsaw pharmacist Konstanty Potocki (1886-1967). Before the war, he was a wholesaler, pharmaceutical industrialist and co-organizer of the pharmaceutical production plant “Dr farm K. Wende. Industrial and Commercial Plants Ltd”. His pharmacy was located at Krakowskie Przedmieście 45 Street, and from 1943 on Aleje Jerozolimskie Street in Warsaw. Potocki, with his own money, led Hirszfeld out of the Warsaw ghetto in July 1942, when the mass deportation of Jews to Treblinka was initialized. Personally, it was engineer D., a figure unknown today, who came to the ghetto for him and announced that there was a car waiting on the Aryan side. Grateful for the offer, Hirszfeld wrote in his memoirs: “My cordial love for young people evidently lived in the memory of this kind man. I accept the offer with the deepest emotion”. The Hirszfeld family left the ghetto disguised as workers.

Potocki was a Protestant, he rests in the Evangelical-Augsburg Cemetery. He did not receive the title of “Righteous Among the Nations”.