Gerhard Volkheimer

Over a period of almost twenty years (1948–1967), Gerhard Volkheimer rendered outstanding service to gastroenterological research at Berlin’s Humboldt University. Gerhard Volkheimer’s scientific work focused on the small intestine – together with his team, he conducted extensive research on persorption [LINK] at the Faculty of Medicine of the Charité.

In conjunction with his work as a scientist, Volkheimer also practiced as a clinical gastroenterologist at his own practice at Berlin’s Bayerischer Platz. His situation was extremely unusual: Volkheimer conducted his research in East Berlin but yet lived and ran his practice in the West of the city. After he was forced to leave the Charité in 1967 ^{[1]1Volkheimer, Gerhard: Ich war der letzte oder vorletzte West-Berliner an der Charité. In: Stein, Rosemarie: Die Charité: 1945 - 1992; ein Mythos von innen, S. 43 ff. Argon-Verlag, Berlin 1992.}, he transferred to the Freie Universität Berlin (FU) to which his habilitation was transferred in 1969. However, he was unable to continue his research on the topic of persorption because at the FU he no longer had access to the infrastructure of the Charité in terms of laboratories, equipment, teams of staff and doctoral students.

In addition to his experimental research, Gerhard Volkheimer was consistently active in communicating knowledge and methodology. To serve this end, he not only supervised numerous PhD students at the Charité, but also attracted affection and respect for both his teaching and organizational skills.

In addition to all this work, he was responsible for many developments in functional gastroenterological diagnostics, in rigid and flexible endoscopy and in X-ray diagnostics of the digestive tract. Among his achievements was to acquire an orbiscope for his practice – the most modern X-ray machine available at the time. ^{[2]2Volkheimer, Gerhard: Gastroenterologie für die Praxis. Lehmann, München 1975. (siehe http://d-nb.info/750265477} Gerhard Volkheimer retired from his activities as a gastroenterologist in 1993.

Born on July 11 in Kempten, Allgäu
† 6. Januar 2021

The process of persorption was demonstrated by Gerhard Volkheimer and his team of employees using experiments on animals and human subjects.^{[4]4Volkheimer, Gerhard: Durchlässigkeit der Darmschleimhaut für großkorpuskuläre Elemente. Berlin, Humboldt University Medical Faculty, habilitation paper, Jan. 31, 1962. (see http://d-nb.info/481107614/}

He became aware of early work by Herbst (1844) and Rahel Hirsch (1905), ^{[5]5Documentation „Ärztinnen im Kaiserreich“: Entry „Rahel Hirsch“. Institute for the History of Medicine and Ethics in Medicine, Charité – Universitätsmedizin Berlin. https://geschichte.charite.de/aeik/biografie.php?ID=AEIK00127, July 2, 2018.[6]6Ben Zev, Hedvah: Preußens erste Medizinprofessorin. In: Jüdische Miniaturen, Band 24, S. 56/57.. Stiftung Neue Synagoge Berlin – Centrum Judaicum. Berlin 2005.}, who had found undissolved particles at a scale measured in micrometers in the blood of starch-fed animals that could not be explained by the absorption mechanisms known at the time^[7]7 , including diffusion, enzymatic degradation and micropinocytosis.

Through experimentation on animals and on his own body, Volkheimer discovered a mechanism of encapsulation of larger particles, a process he called “persorption“.

Gerhard Volkheimer’s discovery of the persorption process “moved the wheel of medical progress that little bit further forward.”

The phenomenon of persorption is also relevant to contemporary studies in marine biology and environmental science, including questions related to industrial dusts, plastic waste in the oceans, their retention in human and animal bodies, and the associated effects. Volkheimer’s work is important in the formation of health policy and has probably also made a contribution to safety in industrial workplaces.